Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis

The effects of back extensor strength in different body positions on health-related quality of life in patients with degenerative spinal deformity

BACKGROUND

Degenerative spinal deformity (DSD) is believed to originate from degeneration of the discs and facet joints and vertebral wedging. Currently, the nosogeny of DSD is not yet fully clarified and there has been no systematic study on the impact of their lower back muscle strength on quality of life.

OBJECTIVE

To determine the characteristics of back extensor strength (BES) in different body positions and examine their correlations with health-related quality of life (HQOL) in degenerative spinal deformity (DSD) patients.

METHODS

Participants comprised 60 DSD patients and 40 healthy volunteers. Maximal isometric BES was evaluated by dynamometers with the subject in three different positions (standing, prone, sitting). The visual analogue scale (VAS) score, Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMQ), and 36-item Short Form Health Survey (SF-36) score were used to evaluate patient HQOL. Correlations between the BES in different body positions and HQOL were analysed.

RESULTS

The BES values in three body positions were significantly smaller in DSD patients than healthy subjects (P< 0.05). The standing BES was found to be negatively associated with ODI and RMQ (R= 0.313, p< 0.05 and R= 0.422, p< 0.01, respectively). A negative relationship between sitting BES and RMQ was also seen (R= 0.271, p< 0.05). In addition, the standing and prone BES were positively correlated with the physical functioning score of the SF-36 (R= 0.471, p< 0.01 and R= 0.289, p< 0.05, respectively), and the sitting BES was positively correlated with the role-physical score of the SF-36 (R= 0.436, p< 0.01).

CONCLUSION

The results indicate that the back extensor muscle is compromised in DSD patients and there are differences in predicting the severity of disability and physical HQOL scores with BES in different positions. Standing BES was the most reliable contributor to HQOL among three body positions.

[Sagittal Profi le of the Spine in Patients after Lumbar Stabilisation Surgeries]

PURPOSE OF THE STUDY

Spine stabilization surgery is nowadays one of the most common spinal surgical procedures. Spinopelvic alignment is considered to be an important factor impacting the patients' preoperative diffi culties as well as the outcome of surgery. In our study, the outcomes of stabilization surgeries in patients with lumbar spine disorders were evaluated - especially in those with stenosis and spondylolisthesis, in whom the importance of sagittal parameters were assessed with respect to the patients' clinical outcomes and diffi culties.

MATERIAL AND METHODS

The study included 50 patients with lumbar spine disorders who had undergone a spine stabilization surgery for a degenerative disease - lumbar spinal stenosis, spondylolisthesis between 2015 and 2017. Spino-pelvic radiological parameters and clinical parameters were evaluated using the nonparametric Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests.

RESULTS

In 38 of 50 patients, who at the end of the follow-up period did not have the PI-LL (pelvic incidence-lumbar lordosis) mismatch, i.e. PI-LL was ≤10°, a statistically signifi cant difference in pelvic tilt (p=0.049) and sagittal vertical axis (p<0.001) was reported, which was not the case in the remaining patients of the study population. Claudication and OSWESTRY (ODI) showed no statistically signifi cant difference. We have also compared the differences in the number of fused vertebrae and type of stabilization. A signifi cant change was seen in the claudication parameter at 12 and 24 months after surgery (p=0.007, p=0.005), with better outcomes achieved by 360° lumbar fusion compared to posterior lumbar fusion. The improvement of VAS and ODI scores in both the groups over time (from 6.1 to 3.6 or from 6.3 to 3.5 in VAS and from 62 to 32, or from 62 to 30 in ODI) was also statistically signifi cant (p<0.001 in both groups), while when comparing the groups against each other it was statistically insignifi cant.

DISCUSSION

The authors confi rmed signifi cant improvement in the studied clinical parameters in all groups of patients (VAS, ODI, claudication), which is consistent with the results of recently published papers. The authors also established the correlation between different radiological parameters in the studied groups. The results do not confi rm the importance of the length or type of instrumentation for the clinical outcomes. This is consistent with the fi ndings of other published manuscripts. The authors failed to confi rm a signifi cant change in clinical parameters in dependence on the matching relationship between the pelvic incidence and lumbar lordosis.

CONCLUSIONS

Proper spinopelvic balance in patients after spinal surgery is a very important indicator of postoperative development and condition, but our cohort showed no statistically signifi cant difference in the clinical outcomes of patients whose postoperative sagittal parameters were unsatisfactory.

KEY WORDS

sagittal profi le, spine stabilization, pelvic tilt, pelvic incidence, sagittal vertical axis, SVA.

Sedentary lifestyle of university students is detrimental to the thoracic spine in men and to the lumbar spine in women

BACKGROUND

Sitting for long periods of time and lack of physical activity in young adults can cause postural deterioration leading to rapid onset of fatigue and increase the risk of back pain. We were interested in whether there are gender differences in spinal curvature among university students with a predominantly sedentary lifestyle.

METHODS

20 sedentary female (age 20 ± 0.73 years) and 39 sedentary male university students (age 20 ± 1.08 years) participated in this study. Their thoracic and lumbar curvatures were assessed while standing and sitting using a Spinal Mouse.

RESULTS

In standing, 80.0% of the females and 69.2% of the males had a neutral position of the thoracic spine (33.25° and 35.33°, respectively). However, more males, 30.8%, than females, 10.0%, had hyperkyphosis (54.27° and 47.0°, respectively). Hypokyphosis was found in 10.0% of the females (18.50°) and none in the males. Similarly, 90.0% of the females and 97.4% of the males had neutral position of the lumbar spine (-33.11° and -29.76°, respectively). Increased hyperlordosis was found in 10.0% of the females and 2.6% of the males (-41.0° and -50.0°, respectively). Hypolordosis was not detected in either females or males. In sitting, on the other hand, 70.0% of the females and only 33.3% of the males had a neutral position of the thoracic spine (30.20° and 30.62°, respectively). Increased hyperkyphosis was found in 46.2% of the males (59.76°) and none of the females. 30.0% of the females and 23.1% of the males had light hypokyphosis (47.50° and 46.67°, respectively). Similarly, 70.0% of the females and only 38.5% of the males had a neutral position of the lumbar spine (7.0° and 6.6°, respectively). 35.9% of the males and only 5.0% of the females had a light hypokyphosis (16.14° and 16.0°, respectively). Slightly increased hyperkyphosis was identified in 25.6% of the males and 25.0% of the females (23.9° and 22.5°, respectively).

CONCLUSION

There are significant gender differences in spinal curvature. While in the thoracic spine it was to the detriment of the males when both standing and sitting, in the lumbar spine it is related to the females only when standing. It is therefore necessary to eliminate these spinal deviations in young adults induced by prolonged sitting during university courses by appropriate recovery modalities.

The Relationship Between Low Back Pain and Sagittal Spinal Alignment and Back Muscle Mass in Korean Fishery Workers

OBJECTIVE

To investigate the relationship between low back pain (LBP) and sagittal spino-pelvic parameters along with the relationship between LBP and back muscle mass in Korean male and female fishery workers.

METHODS

This retrospective study included a total of 146 subjects who underwent Fishermen's health survey conducted between June 2018 and August 2020. LBP was evaluated through visual analogue scale (VAS) and Oswestry Disability Index (ODI). Sagittal spino-pelvic parameters were measured from whole spine standing X-rays. Back muscle cross-sectional areas were identified through lumbar spine magnetic resonance imaging and body composition was analyzed through bioelectrical impedance analysis.

RESULTS

The study included 75 males and 71 females, with an average age of 58.33 years for males and 56.45 years for females. Female subjects exhibited higher VAS and ODI scores, larger pelvic tilt (PT) and trunk fat mass and smaller trunk muscle mass compared to males. In female, ODI positively correlated with sagittal vertical axis (SVA) and PT. No significant correlations were found between ODI scores and body composition in either sex. The high ODI group showed greater SVA, PT, and pelvic incidence-lumbar lordosis and higher trunk fat/muscle ratio. Psoas muscle mass, total and skeletal muscle mass and trunk muscle mass of that group were smaller than those of low ODI group.

CONCLUSION

Spino-pelvic parameters and back muscle mass were associated with ODI and there were differences between Korean male and female fishery workers.

Risk Factors for Distal Junctional Problems Following Long Instrumented Fusion for Degenerative Lumbar Scoliosis: Are they Related to the Paraspinal Muscles

PURPOSE

Although the incidence of distal junctional problems (DJPs) following long construct-based treatment for degenerative lumbar scoliosis (DLS) is lower, affected patients are more likely to require revision surgery when they occur. So the aim of this study is to identify risk factors associated with DJPs to avoid its occurrence by at least 1-year follow-up.

METHODS

A total of 182 DLS patients undergoing long instrumented fusion surgery (≥4 levels) between February 2011 and March 2022 were retrospectively analyzed. Patients were placed into the DJP group if a DJP occurred at the final follow-up; patients without mechanical complications were matched 1:2 according to age, sex and BMI as the control group. Patient characteristics, surgical variables, radiographic parameters, lumbar muscularity and fatty degeneration were analyzed statistically. The statistical differences in the results between the two groups (p values <0.05) and other variables selected by experts were entered into a multivariate logistic regression model, and the forwards likelihood ratio method was used to analyze the independent risk factors for DJPs.

RESULTS

Twenty-four (13.2%) patients suffered a DJP in the postoperative period and the reoperation rate was 8.8%. On univariate analysis, the lowest instrumented vertebra (LIV) CT value (p = 0.042); instrumented levels (p = 0.030); preoperative coronal vertical axis (CVA) (p = 0.046), thoracolumbar kyphosis (TLK) (p = 0.006), L4-S1 lordosis (p = 0.013), sacral slop (SS) (p = 0.030), pelvic tilt (PT) classification (p = 0.004), and sagittal vertical axis (SVA) (p = 0.021); TLK correction (p = 0.049); post-operative CVA (p = 0.029); Overall, There was no significant difference in the paraspinal muscle parameters between the two groups. On multivariate analysis, instrumented levels (OR = 1.595; p = 0.035), preoperative SVA (OR = 1.016; p = 0.022) and preoperative PT (OR = 0.873; p = 0.001) were identified as significant independent risk factors for DJP.

CONCLUSION

Longer instrumented levels, a greater preoperative SVA and a smaller PT were found to be strongly associated with the presence of DJPs in patients treated for DLS. The degeneration of the paraspinal muscles may not be related to the occurrence of DJPs. For DLS patients, the occurrence of DJP can be reduced by selecting reasonable fusion segments and evaluating the patient's sagittal balance and spino-pelvic parameters before operation.

Transforaminal lumbar interbody fusion with an expandable interbody device: Two-year clinical and radiographic outcomes

Background

The use of interbody cages as an adjunct to lumbar spinal fusion remains an important technique to enhance segmental stability, promote solid arthrodesis, maintain neuroforaminal decompression, and preserve/improve segmental lordosis. Appropriate segmental lumbar lordosis and sagittal balance is well-known to be critical for long-term patient outcomes. This study sought to evaluate the radiographic and clinical results of TLIF in patients using an articulating, expandable cage. Primary endpoint was clinical and radiographic outcomes, including complications, at 12 and 24 months.

Methods

A total of 37 patients underwent open single-level or 2-level TLIF by a single surgeon using an expandable cage with concomitant bilateral pedicle screws and posterolateral arthrodesis. Clinical outcomes included ODI and VAS for back and legs. Radiographic outcomes included pelvic incidence and tilt, lumbar and segmental lordoses, and disc height at the operative level(s). All outcomes were collected at baseline, 2-weeks, 6-weeks, 3-months, 6-months, 12-months, and 24-months postop.

Results

A total of 28 patients were available for analysis. Nine patients failed to follow-up at 24 months. Mean ODI scores showed significant improvement, from pre-to-postoperative at 24 months (55%; p<.0001). VAS for back and legs was significantly lower at 24 months on average by 72 and 79%, respectively (p<.0001 for both). Both segmental and lumbar lordoses significantly improved by 5.3° and 4.2° (p<.0001 and p=.049), respectively. Average disc height improved by 49% or 6.1 mm (p<.001). No device-related complications nor instances of measured subsidence. One patient had a superficial infection, and another had an intraoperatively repaired incidental durotomy.

Conclusions

The use of an expandable cage contributed to improvement in both segmental and lumbar lordosis with no reported complications at 24-month follow-up. All clinical measures significantly improved as well. The expandable cage design represents an effective and safe option to increase cage size and allow significant segmental lordosis correction.

Outcomes of Ponte osteotomy combined with posterior lumbar interbody fusion for reconstruction of coronal and sagittal balance in degenerative scoliosis

PURPOSE

The purpose of the study was to evaluate the clinical efficacy and safety of using Ponte osteotomy combined with posterior lumbar interbody fusion in the treatment of patients with degenerative scoliosis.

METHOD

The medical records and imaging data of degenerative scoliosis patients in our department from 2013 to 2022 were retrospectively collected. A total of 47 patients were included, including 16 male patients and 31 female patients. The mean follow-up was 47.8 months. Whole spine X-rays in the standing position were performed on all patients preoperatively, postoperatively, and at the latest follow-up. The length of hospital stay, complications, operative duration, estimated blood loss, instrumented segment, fused segment, clinical scores, and various radiological indicators were recorded.

RESULTS

The coronal vertical axis improved from 3.1 ± 1.9 cm preoperatively to 1.2 ± 1.0 cm postoperatively with an average reduction of 1.9 ± 1.7 cm. The preoperative coronal Cobb angle was 18.1 ± 10.6°, the immediate postoperative Cobb angle was 6.6 ± 3.9°, and the Cobb angle at the last follow-up was 5.8 ± 3.7°. The sagittal vertical axis decreased from 5.6 ± 3.7 cm preoperatively to 2.7 ± 1.9 cm immediately after the operation and was well maintained at the last follow-up (3.1 ± 2.5 cm). Lumbar lordosis increased from 22.2 ± 10.2° preoperatively to 40.4 ± 8.3° postoperatively and 36.0 ± 8.8° at the last follow-up. The ODI score, VAS low back pain score, and VAS leg pain score were also improved to varying degrees.

CONCLUSION

Ponte osteotomy combined with posterior lumbar interbody fusion can significantly improve coronal and sagittal plane deformities and postoperative functional scores in patients with adult degenerative scoliosis.

Lasso Analysis of Gait Characteristics and Correlation with Spinopelvic Parameters in Patients with Degenerative Lumbar Scoliosis

PURPOSE

This study quantifies the gait characteristics of patients with degenerative lumbar scoliosis (DLS) and patients with simple lumbar spinal stenosis (LSS) by means of a three-dimensional gait analysis system, aiming to determine the image of spinal deformity on gait and the correlation between spinal-pelvic parameters and gait characteristics in patients with DLS to assist clinical work.

METHODS

From June 2020 to December 2021, a total of 50 subjects were enrolled in this study, of whom 20 patients with DLS served as the case group and 30 middle-aged and elderly patients with LSS were selected as the control group according to the general conditions (sex, age, and BMI) of the case group. Spinal-pelvic parameters were measured by full-length frontal and lateral spine films one week before surgery, and kinematics were recorded on the same day using a gait analysis system.

RESULTS

Compared to the control group, DLS patients exhibited significantly reduced velocity and cadence; gait variability and symmetry of both lower limbs were notably better in the LSS group than in the DLS group; joint ROM (range of motion) across multiple dimensions was also lower in the DLS group; and correlation analysis revealed that patients with a larger Cobb angle, T1PA, and higher CSVA tended to walk more slowly, and those with a larger PI, PT, and LL usually had smaller stride lengths. The greater the PI-SS mismatch, the longer the patient stayed in the support phase. Furthermore, a larger Cobb angle correlated with worse coronal hip mobility.

CONCLUSIONS

DLS patients demonstrate distinctive gait abnormalities and reduced hip mobility compared to LSS patients. Significant correlations between crucial spinopelvic parameters and these gait changes underline their potential influence on gait disturbances in DLS. Our study identifies a Cobb angle cut-off of 16.1 as a key predictor for gait abnormalities. These insights can guide personalized treatment and intervention strategies, ultimately improving the quality of life for DLS patients.

Effect of spinal-pelvic sagittal balance on the clinical outcomes after lumbar fusion surgery

BACKGROUND

Spinal-pelvic sagittal balance is important for maintaining energy-efficient posture in normal and diseased states.Few reports to date have evaluated the effect of spinal-pelvic sagittal balance on clinical outcomes after lumbar interbody fusion in patients with lumbar degenerative diseases (LDD).

METHODS

A total of 303 patients treated with posterior lumbar interbody fusion surgery for lumbar degenerative disease from January 2012 to December 2019 were enrolled in this retrospective study according to the inclusion criteria. Preoperative and postoperative spinal-pelvic sagittal parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL) of the patients were evaluated and compared. 163 patients whose postoperative PI-LL ≤ 10° were divided into the spinal-pelvic match group (Group M), while 140 patients were divided into the spinal-pelvic mismatch group (Group MM). Preoperative and postoperative Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back pain of both groups were compared.

RESULTS

There was no significant difference between the two groups in demographic and surgical data, except for blood loss in surgery. LL, PI, PT and SS of the patients at final follow-up were all statistically different from the preoperative values in the two groups(P < 0.05). There was no significant difference in LL, PI, PT and SS between the two groups before surgery. At the final follow-up, LL, PI and PT differed significantly between the two groups(P < 0.05). Compared with the preoperative results, ODI and VAS of low back in both groups decreased significantly at the final follow-up (P < 0.05). Significant differences in VAS and ODI were found between the two groups at the final follow-up (P < 0.05). The improvement rates of VAS and ODI of Group M are both significantly higher than Group MM. Regression analysis showed that age and spinal-pelvic match had significant effects on the improvement of patients' low back pain at the final follow-up.

CONCLUSIONS

lumbar interbody fusion can significantly improve the prognosis of patients with LDD. In terms of outcomes with an average follow-up time of more than 2 years, the spinal-pelvic match has a positive effect on patients' quality of life and the release of low back pain.

Is the pelvic incidence a determinant factor for kyphosis curve patterns of ankylosing spondylitis patients?

To investigate the influence of pelvic incidence (PI) on the kyphosis curve patterns and clinical outcomes in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis and to construct a classification of AS according to the PI value for surgical decision-making. 107 AS patients underwent single-level lumbar pedicle subtraction osteotomy (PSO) and finished a minimal of 2-year follow-up. All patients were divided into three groups: low PI (PI ≤ 40°), moderate PI (40° < PI ≤ 60°), and high PI (PI > 60°). Standing lateral radiographs were taken to evaluate the location of kyphotic apex, thoracic kyphosis (TK), lumbar lordosis (LL), C7 sagittal vertical axis (SVA), spino-sacral angle (SSA), global kyphosis (GK), PI, sacral slope (SS), and pelvic tilt (PT). Visual Analogue Scale (VAS) score, Oswestry Disability Index (ODI) and Bath Ankylosing Spondylitis Functional Index (BASFI) were used to evaluate quality of life. Before surgery, a significant difference was shown in the average LL and the mean GK in high PI group was the largest among the three groups. Correction of SVA, GK and LL in high PI group was the smallest among the three group. No significant difference in clinical outcomes was found among the three groups before surgery and at the final follow-up. Regarding the preoperative sagittal profile, the kyphosis curve pattern of moderate PI group is similar to that of low PI group. For AS patients in these two groups, harmonious sagittal alignment can be restored by a single-level PSO. However, the sagittal imbalance is insufficiently realigned by a single-level PSO in a patient with high PI.

Morphological description of sagittal lumbar spinal alignment using curve magnitude, span, and apex-the multiethnic alignment normative study (MEANS)

BACKGROUND CONTEXT

Current definition of lumbar lordosis uses the L1-S1 angle. Prevailing classification of sagittal spinal morphology, derived from a young adult population, classifies the spine into four subtypes defined by their sacral slope (SS) and curve morphology.

PURPOSE

To describe physiological sagittal alignment of the lumbar spine across age groups using three main parameters that dictate the lumbar curve: angular magnitude, span, and apex.

STUDY DESIGN

A large, multicenter, cross-sectional radiographic comparison study.

PATIENT SAMPLE

Four hundred sixty-eight healthy, asymptomatic subjects aged 18 to 80 years from five countries (184 males, 284 females; 98 France, 119 Japan, 79 Singapore, 80 Tunisia, 92 USA, mean age 40.61±14.99 years).

OUTCOME MEASURES

Sagittal lumbar profile subtypes clustered based on lumbar curve angular magnitude (ie, Cobb angle of the lumbar lordosis), span, and apex, and described by sagittal radiographic parameters.

METHODS

Subjects underwent whole-body low-dose EOS stereoradiographs. Comparisons between conventional L1-S1 lumbar lordosis (cLL) and true lumbar lordosis (tLL, defined by the inflection-S1 angle) were conducted. Using the K-means clustering algorithm, lumbar curve angular magnitude, span and apex were used to classify sagittal spinal morphology into subtypes, stratified across age groups. Further univariate and multivariate analyses were conducted to compare radiographic parameters across subtypes, and identify predictors for the lumbar curve's angular magnitude, span and apex.

RESULTS

Mean cLL was -57.27±11.37°, and tLL was -62.62±10.76°. Using tLL, instead of cLL, to describe sagittal spinal morphology, we found significant differences in terms of angular magnitude of the lumbar curve, the median thoracolumbar inflection vertebral level and pelvic incidence-lumbar lordosis mismatch Multivariate analysis found a larger SS, more positive T9 tilt, and more kyphotic T4-T12 predictive for a more lordotic tLL, while a larger overhang distance predicted for a less lordotic tLL (p-values<.001). In addition, a larger T9 tilt, less lordotic L1-L5 and smaller PT were predictors of a more caudal thoracolumbar inflection and lumbar apical vertebral levels (p-values<.001). Sagittal lumbar profiles of subjects age<30 years, 30≤age<60 years and age≥60 years, could be classified into 4, 6, and 3 subtypes, respectively.

CONCLUSIONS

Sagittal lumbar profile subtypes vary across age groups, with more homogenous morphologies at the extremes of ages. Improved understanding of the morphological evolution of sagittal spinal profiles with age in asymptomatic individuals will help guide future individualized surgical treatment.

Assessing Alignment Using GAP Score and Complications for Pedicle Subtraction Osteotomy Revision Surgeries for Sagittal Deformity in Previously Fused Spines Using a Satellite Rod Technique

OBJECTIVE

Pedicle subtraction osteotomy (PSO) is a surgical technique to restore lumbar lordosis in patients with rigid sagittal deformity. Herein, we report on outcomes of a surgical technique utilizing a 4-rod PSO with satellite rods.

METHODS

A retrospective study was performed for a cohort of patients who underwent 4-rod PSO revision surgery for sagittal deformity. Procedures were performed by one surgeon at 2 different academic centers between 2004-2018. Alignment outcomes and complications specifically for revision surgeries in previously fused spines were assessed.

RESULTS

40 patients underwent PSO with the satellite rod technique (n = 29 at L3, 72.5%; n = 7 at L4, 17.5%). Mean PSO angle was 28.7 ± 7.6°. Two patients (5%) had rod fracture necessitating revision surgery at 32 and 34 months. Three patients (7.5%) developed proximal junctional kyphosis (PJK), but none required revision. No patients developed pseudoarthrosis. Mean preoperative sagittal vertical axis (SVA) was 13.5 ± 7.3 cm, which decreased to 4.8 ± 7.3 cm (P = 0.002) postoperatively. Mean preoperative pelvic incidence-lumbar lordosis (PI-LL) mismatch improved from 35.9 ± 16.6° preoperatively to 11.8 ± 14.6° postoperatively (P < 0.001). Mean preoperative pelvic tilt (PT) improved from 34.7 ± 9.8° preoperatively to 30.1 ± 9.0° (P = 0.026) postoperatively. Mean global alignment and proportion (GAP) score improved from 10 ± 2 preoperatively to 8 ± 2 postoperatively (P < 0.001), which was still considered severely disproportioned.

CONCLUSIONS

Rod failure rate after PSO with the 4-rod satellite configuration was low. SVA, PI-LL mismatch, and PT significantly improved for these previously-fused patients. Mean GAP score also improved, but was still considered severely disproportioned, likely due to the inability of PSO to correct low LL or PT in previously-fused spines.

Do Age-Related Variations Of Sagittal Alignment Rely On SpinoPelvic Organization? An Observational Study Of 1540 Subjects

STUDY DESIGN

Descriptive radiographic analysis of a prospective multi-center database.

OBJECTIVE

This study aims to provide normative values of spinopelvic parameters and their correlations according to age and pelvic incidence (PI) of subjects without spinal deformity.

METHODS

After Institutional Review Board (IRB) approval, 1540 full spine radiographs were analyzed. Subjects were divided into 3 groups of PI: low PI < 45°, intermediate PI 45-60°, high PI > 60°, and then stratified by age (20-34, 35-49, 50-64, > 65 Y.O). Pelvic and spinal parameters were measured. Statistical analysis between parameters was performed using Bayesian inference and correlation.

RESULTS

Mean age was 53.5 years (845 females, 695 males, range 20-93 years).In low PI group, lumbar lordosis (LL) decrease was mainly observed in the 2 younger age groups.In medium and high PI groups, loss of lordosis was linear during aging and occurred mainly on the distal arch of lordosis. Moderate PI group had a stable lordosis apex and thoracolumbar inflection point. High PI group had a stable thoracolumbar inflection point and a more distal lordosis apex in elderly subjects.For all subjects, kyphosis and pelvic tilt (PT) increased with age.There was a constant chain of correlation between PI and age groups. Proximal lumbar lordosis (PLL) was correlated with kyphosis and sagittal vertical axis (SVA C7), while the distal lumbar lordosis (DLL) was correlated with PI and PT.

CONCLUSION

This study provides a detailed repository of sagittal spinopelvic parameters normative values with detailed analysis of segmental kyphosis and lordosis distribution according to gender, age, and PI.

Measuring Outcomes in Spinal Deformity Surgery

Outcome assessment in adult spinal deformity has evolved from radiographic analysis of curve correction to patient-centered perception of health-related quality-of-life. Oswestry Disability Index and the Scoliosis Research Society-22 Patient Questionnaire are the predominantly used patient-reported outcome (PRO) measurements for deformity surgery. Correction of sagittal alignment correlates with improved PRO. Functional outcomes and accelerometer measurements represent newer methods of measuring outcomes but have not yet been widely adopted or validated. Further adoption of a minimum set of core outcome domains will help facilitate international comparisons and benchmarking, and ultimately enhance value-based healthcare.

Spinopelvic Alignment: Importance in Spinal Pathologies and Realignment Strategies

Sagittal spinal malalignment can lead to pain, decreased function, dynamic imbalance, and compromise of patient-reported health status. The goal of reconstructive spine surgery is to restore spinal alignment parameters, and an understanding of appropriate patient-specific alignment is important for surgical planning and approaches. Radiographic spinopelvic parameters are strongly correlated with pain and function. The relationship between spinopelvic parameters and disability in adult spinal deformity patients is well-established, and optimal correction of sagittal alignment results in improved outcomes regarding patient health status and mechanical complications of surgery.

The Lumbosacral Fractional Curve in Adult Degenerative Scoliosis

Spine surgeons are often faced with a profoundly difficult challenge in surgically treating adult degenerative scoliosis. Deformity correction surgery is complicated by the difficulty in offering extensive surgical corrections to the elderly, complication-prone population it commonly affects. As spine surgeons attempt to offer minimally invasive solutions to this disease process, the need for fusion of the fractional curve at L4, L5, and S1 may be discounted. A treatment strategy to identify, address, and treat the fractional curve with either open or minimally invasive techniques can lead to improved patient outcomes and decrease revision rates in this complicated pathologic process.

The Correlation of Global Spinal Realignment With the Quality of Life After Corrective Surgery for Delayed Thoracolumbar Osteoporotic Fracture-Related Kyphosis

BACKGROUND AND OBJECTIVES

Few studies have been conducted to evaluate the precise impact of corrective surgery on sagittal spinal realignment and clinical outcomes in cases of delayed thoracolumbar osteoporotic fracture-related kyphosis. To assess the efficacy of corrective surgery on sagittal spinal alignment and investigate the relationship between spinal alignment and health-related quality of life (HRQoL) in patients with delayed thoracolumbar osteoporotic fracture-related kyphosis.

METHODS

A total of 78 patients were enrolled. The characteristics and surgical variables were meticulously documented. The sagittal spinal parameters were measured, and the HRQoL was evaluated using Oswestry Disability Index (ODI), SF-12 Physical Component Score (SF-12 PCS), and Scoliosis Research Society-22 Patient Questionnaire (SRS-22) before and after surgery. The changes in spinal parameters and HRQoL were analyzed through the paired t -test. The Pearson correlation analysis was performed to analyze the correlation of parameters with HRQoL. Then, a multiple stepwise regression analysis was performed with HRQoL scores as the dependent variable and spinal parameters as the independent variable.

RESULTS

The operative time was 185.9 ± 33.2 min, and the estimated blood loss was 782.8 ± 145.2 mL. The results of the paired t -test revealed a significant difference preoperatively and at the final follow-up in the thoracic kyphosis, thoracolumbar kyphosis (TLK), lumbar lordosis, T9 tilt, pelvic tilt, sacral slope, sagittal vertical axis, and spinosacral angle as well as the ODI, SF-12 PCS, and SRS-22 ( P < .05). Multiple stepwise regression analysis revealed that TLK and pelvic tilt, TLK and sagittal vertical axis, and TLK were the primary parameters affecting the ODI, SF-12 PCS, and SRS-22, respectively.

CONCLUSION

Corrective surgery can effectively realign the global spine and improve HRQoL in patients with delayed thoracolumbar osteoporotic fracture-related kyphosis. The change of TLK is a driving factor to realign the global spine.

Posterior-based Osteotomies for Deformity Correction

Posterior-based osteotomies are crucial to the restoration of lordosis in adult spinal deformity. Posterior-column osteotomies are suited for patients with an unfused anterior column and non-focal sagittal deformity requiring modest correction in lordosis. When performed on multiple levels, posterior-column osteotomy may provide significant harmonious correction in patients who require more extensive correction. Pedicle subtraction osteotomy and vertebral column resection are appropriate for patients with a fused anterior column and more severe deformity, particularly focal and/or multiplanar deformity. The power of pedicle subtraction osteotomy and vertebral column resection to provide greater correction and to address multiplanar deformity comes at the cost of higher complication rates than posterior-column osteotomy.

Proximal and distal mechanical repercussions of instrumentation by double rods and interbody grafts in adult scoliosis

INTRODUCTION

Correction of adult scoliosis by instrumentation with double rods and interbody grafts aims to reduce the risk of pseudarthrosis with rod fracture. An increase in instrumentation rigidity can lead to an increase in stresses at the proximal and distal ends of the construct. The aim of this study was to analyze the incidence and clinical repercussions of proximal junctional kyphosis (PJK), proximal junctional failure (PJF) and iliac screw loosening.

MATERIEL AND METHODS

An analysis of patients operated on for adult scoliosis with instrumentation to the pelvis using 4 rods and interbody cages was carried out from a prospective register. The Visual Analog Scale (VAS), Oswestry Disability Index (ODI), Scoliosis Research Society 22 (SRS-22) clinical scores and radiological parameters were collected preoperatively, postoperatively at 3 months, 1 year and 2 years. The appearance of PJK, PJF or distal screw loosening was sought; the clinical impact and the risk factors were analyzed by Bayesian inference.

RESULTS

Fifty-one patients with a mean age of 64.5 years were included. The clinical scores improved significantly (Pr>0.95) at 2 years: VAS back 6.9 versus 2.6, VAS leg 4.9 versus 2.5, ODI 48.2 versus 25.4, SRS-22 2.4 versus 3.5. The radiological parameters were corrected (Pr>0.95): Cobb angle 63.9° versus 22.8°, spinosacral angle (SSA) 112.4° versus 118.8°, T1-pelvic angle (TPA) 24, 8° versus 20.8°, lumbar lordosis 43.8° versus 51.0°, thoracic kyphosis 45.2° versus 53.6°. Thirteen patients (25.5%) presented with PJK and 11 (21.6%) with PJF. Seven patients (13.7%) presented with iliac screw loosening. None of these complications was associated with a significant deterioration in clinical scores. Cranial migration of the lumbar apex increased the risk of distal screw loosening: Odds-Ratio 10.31 (Pr>0.999). Two patients were re-operated on for PJF and one patient for iliac screw loosening (5.9%). No rod fracture with pseudarthrosis was found.

CONCLUSION

Instrumentation with double rods and interbody grafts was associated with a rate of 47.1% of mechanical repercussions at the extremity of the construct. However, these complications were not associated with a significant deterioration in clinical scores.

LEVEL OF EVIDENCE

III.

Influence of Spinopelvic Alignment on the Clinical Outcomes Following Decompression Surgery for Lumbar Stenosis

Introduction The role of sagittal spinopelvic alignment in lumbar spinal stenosis (LSS) patients and its potential influence on post-decompression surgery outcomes is a topic of growing interest. Lumbar spinal stenosis is a prevalent degenerative condition, and with an aging population, the frequency of surgical interventions for LSS has risen. While decompression surgery aims to relieve symptoms, the potential impact of preoperative spinopelvic alignment on postoperative results remains controversial. This study examined the correlation between sagittal spinopelvic parameters and clinical outcomes in LSS patients undergoing decompression surgery. Methods This study included 100 patients with LSS who underwent decompression surgery between 2021 and 2023 and 100 healthy individuals as a control group. The LSS group comprised 50 men and 50 women, with a mean age of 55.8±12.41 years, while the control group consisted of 50 men and 50 women, with a mean age of 55.17±13.39 years. Sagittal spinopelvic alignment parameters, including pelvic tilt (PT), pelvic incidence-lumbar lordosis mismatch, and sagittal vertical axis, were assessed preoperatively. Postoperative clinical outcomes were evaluated using the visual analog scale (VAS) and Oswestry disability index (ODI) scores. Results In the cohort of 200 participants, 100 were diagnosed with lumbar spinal stenosis (LSS), and 100 were healthy controls. Both groups had an equal gender distribution (50 males and 50 females). The mean age was 55.8 (±12.4) years for the LSS group and 55.2 (±13.4) years for the control group. Among the analyzed radiographic parameters, only lumbar lordosis (LL) levels showed a significant difference between groups, notably lower in the LSS group (p=0.020). Preoperative VAS scores in LSS patients averaged 7.58±1.32, which postoperatively dropped to 2.22±1.95 (p<0.001). Similarly, ODI (%) declined from a preoperative average of 55.76±11.65 to 18.62±18.17 postoperatively (p<0.001). Patients with postoperative ODI levels exceeding 20% had higher preoperative scores and significantly altered radiographic measurements. The receiver operating characteristic (ROC) analysis indicated PT as the most predictive radiographic parameter, with an area under the curve (AUC) of 0.945. Multivariate logistic regression pinpointed PT and LL as key predictors associated with increased risks for postoperative Oswestry disability levels exceeding 20%. Conclusion Our study suggests that sagittal spinopelvic alignment plays an important role in the development and progression of LSS. Addressing sagittal alignment may be crucial for achieving optimal clinical outcomes after decompression surgery. Further research is needed to elucidate the mechanisms underlying the relationship between sagittal alignment and LSS.

Internal Chain of Correlation of Sagittal Cervical Alignment in Asymptomatic Subjects

STUDY DESIGN

Cross-sectional observational study in a prospective cohort.

OBJECTIVE

To analyze the cervical alignment characteristics and their chain of correlation in a sample of asymptomatic individuals.

METHODS

Asymptomatic adults who had full spinal radiographs performed. Cervical radiographic parameters were measured, including upper cervical curvature (McGregor line-C2), lower cervical curvature (C2-C7), McGregor slope, and sagittal vertical axis from C2-C7 (CSVA) and T1-slope (T1S). Subjects were stratified by age into 3 groups (18-39 years, 40-59 years, and >60 years), and radiographic parameters were compared across age groups and based on sex.

RESULTS

102 asymptomatic subjects (mean age, 50 years) were included. The T1S significantly increased with age, accompanied by an increase in C2-C7 lordosis. The cervical sagittal alignment, represented by CSVA, did not significantly differ based on age. There was a close correlation among the cervical sagittal parameters, such that the CSVA may be predicted based on the T1S and C2-C7 lordosis. Comparisons of the normative values identified in the present study with those reported in previous studies demonstrate variability in what constitutes normal in different populations.

CONCLUSION

This analysis of cervical alignment in a sample of asymptomatic volunteers revealed that with increasing age there is an observed increase in the sagittal inclination of the base of the cervical spine (T1S) that is accompanied by an increase in cervical lordosis as a means of maintaining cervical sagittal alignment (CSVA). The variability in what constitutes normal values for cervical parameters suggests that further study is warranted using standardized methodologies across diverse populations.

Evaluation of intraoperative coronal alignment using a computer-assisted rod bending system (CARBS) without intraoperative radiation exposure in adult spinal deformity surgery: a technical note and preliminary results

PURPOSE

Intraoperative radiographs and fluoroscopy are used in adult spinal deformity (ASD) surgery to prevent postoperative coronal malalignment but with limited accuracy. Therefore, we applied a computer-assisted rod bending system (CARBS: Bendini®) for an intraoperative coronal alignment evaluation. The purpose of this study is to introduce this novel technique and validate its accuracy.

METHODS

Fifteen ASD patients were included in the study. The heads of the bilateral S1 pedicle screws (S1), the S1 spinous process, and the bilateral greater trochanter (GT) and the C7 spinous process were recorded with CARBS for an intraoperative coronal alignment evaluation. The lines which connect the bilateral S1 and GT were used as references. The C7-center sacral vertical line (C7-CSVL) on the CARBS monitor was checked, and the C7-CSVL from the intraoperative CARBS recording and postoperative standing whole spine radiograph were compared.

RESULTS

Intraoperative C7-CSVL with CARBS was 35.1 ± 31.6 mm when the S1 pedicle screws were used as the reference line and was 16.6 ± 17.8 mm when the GTs were used. Postoperative C7-CSVL by radiograph was 15.1 ± 16.5 mm. In addition, the intraoperative C7-CSVL with CARBS and the postoperative C7-CSVL showed a strong positive correlation in both GT (R = 0.86, p < 0.01) and in S1(R = 0.79, p < 0.01), with a better correlation found in GT than in S1.

CONCLUSION

Intraoperative C7-CSVL with CARBS was found to be highly accurate in ASD surgery. Our results suggest that this novel technique can be useful as an alternative to intraoperative radiography and fluoroscopy and may reduce radiation exposure.

External Validation of the Global Alignment and Proportion Score as Prognostic Tool for Corrective Surgery in Adult Spinal Deformity: A Systematic Review and Meta-Analysis

BACKGROUND

Since its proposal, the Global Alignment and Proportion (GAP) score has been the topic of several external validation studies, which have yielded conflicting results. Given the lack of consensus regarding this prognostic tool, the authors aim to assess the accuracy of GAP scores for predicting mechanical complications following adult spinal deformity correction surgery.

METHODS

A systematic search was performed using PubMed, Embase, and Cochrane Library for the purpose of identifying all studies evaluating the GAP score as a predictive tool for mechanical complications. GAP scores were pooled using a random-effects model to compare patients reporting mechanical complications after surgery versus those reporting no complications. Where receiver operator curves were provided, the area under the curve (AUC) was pooled.

RESULTS

A total of 15 studies featuring 2092 patients were selected for inclusion. Qualitative analysis using Newcastle-Ottawa criteria revealed moderate quality among all included studies (5.99/9). With respect to sex, the cohort was predominantly female (82%). The pooled mean age among all patients in the cohort was 58.55 years, with a mean follow-up of 33.86 months after surgery. Upon pooled analysis, we found that mechanical complications were associated with higher mean GAP scores, albeit minimal (mean difference = 0.571 [ 95% confidence interval: 0.163-0.979]; P = 0.006, n = 864). Additionally, age (P = 0.136, n = 202), fusion levels (P = 0.207, n = 358), and body mass index (P = 0.616, n = 350) were unassociated with mechanical complications. Pooled AUC revealed poor discrimination overall (AUC = 0.69; n = 1206).

CONCLUSIONS

GAP scores may have a minimal-to-moderate predictive capability for mechanical complications associated with adult spinal deformity correction.

Impact of Navigation on 30-Day Outcomes for Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective database study.

OBJECTIVE

Navigation has been increasingly used to treat degenerative disease, with positive radiographic and clinical outcomes and fewer adverse events and reoperations, despite increased operative time. However, short-term analysis on treating adult spinal deformity (ASD) surgery with navigation is limited, particularly using large nationally represented cohorts. This is the first large-scale database study to compare 30-day readmission, reoperation, morbidity, and value-per-operative time for navigated and conventional ASD surgery.

METHODS

Adults were identified in the National Surgical Quality Improvement Program (NSQIP) database. Multivariate regression was used to compare outcomes between navigated and conventional surgery and to control for predictors and baseline differences.

RESULTS

3190 ASD patients were included. Navigated and conventional patients were similar. Navigated cases had greater operative time (405 vs 320 min) and mean RVUs per case (81.3 vs 69.7), and had more supplementary pelvic fixations (26.1 vs 13.4%) and osteotomies (50.3 vs 27.7%) (P <.001).In univariate analysis, navigation had greater reoperation (9.9 vs 5.2%, P = .011), morbidity (57.8 vs 46.8%, P = .007), and transfusion (52.2 vs 41.8%, P = .010) rates. Readmission was similar (11.9 vs 8.4%). In multivariate analysis, navigation predicted reoperation (OR = 1.792, P = .048), but no longer predicted morbidity or transfusion. Most reoperations were infectious and hardware-related.

CONCLUSIONS

Despite controlling for patient-related and procedural factors, navigation independently predicted a 79% increased odds of reoperation but did not predict morbidity or transfusion. Readmission was similar between groups. This is explained, in part, by greater operative time and transfusion, which are risk factors for infection. Reoperation most frequently occurred for wound- and hardware-related reasons, suggesting navigation carries an increased risk of infectious-related events beyond increased operative time.

Reciprocal Change of Cervical Spine after Posterior Spinal Fusion for Lenke Type 1 and 2 Adolescent Idiopathic Scoliosis

Reciprocal sagittal alignment changes after adolescent idiopathic scoliosis (AIS) posterior corrective surgery have been reported in the cervical spine, but the evidence is not yet sufficient. Furthermore, much remains unknown about the effects of cervical kyphosis on clinical outcomes in AIS. Forty-five consecutive patients (4 males and 41 females) with AIS and Lenke type 1 or 2 curves underwent a posterior spinal fusion, and a minimum of 24-month follow-up was collected from our prospective database. We investigated radiographic parameters and SRS-22r. Before surgery, cervical kyphosis (cervical lordosis < 0°) was present in 89% and cervical hyperkyphosis (cervical lordosis < -10°) in 60%. There were no significant differences in age, sex, or Lenke type between the hyperkyphosis and the non-hyperkyphosis groups. Although cervical lordosis increased significantly after surgery, cervical kyphosis was observed in 73% of patients 2 years after surgery. We found a significant correlation between Δthoracic kyphosis (TK) and Δcervical lordosis. Preoperative cervical kyphosis, ΔT1 slope, and ΔTK were independently associated factors for postoperative cervical hyperkyphosis. The cervical hyperkyphosis group had significantly lower SRS-22r domains. In AIS corrective surgery, restoring TK leading to a gain of T1 slope may lead to an improvement of cervical sagittal alignment. Remaining cervical hyperkyphosis after AIS surgery may affect clinical outcomes.

Does locomotive syndrome severity predict future fragility fractures in community-dwelling women with osteoporosis?

OBJECTIVES

We investigated whether the locomotive syndrome (LS) severity affects future fragility fractures in osteoporosis patients.

METHODS

In this retrospective cohort study, 315 women with osteoporosis (mean follow-up period, 2.8 years) were reviewed, of whom 244 were included in the analysis. At baseline, we obtained medical information, bone mineral density of the lumbar spine and femoral neck, and sagittal vertical axis. Additionally, LS risk was assessed using the two-step test, stand-up test, and 25-question geriatric locomotive function scale scores. The LS risk test results were used to classify LS severity, which was rated on a 4-point scale from stage 0 (robust) to 3 (worsening). Cox proportional hazards regression analysis was used to determine the association of the severity with future fragility fracture.

RESULTS

Fragility fractures occurred in 37 of 315 participants (11.8%). This study showed that sagittal vertical axis (hazard ratio = 1.014; 95% confidence interval, 1.005-1.023; p value = 0.003) and LS severity (hazard ratio =1.748; 95% confidence interval, 1.133-2.699; p = 0.012) were independent risk factors for incidence of fragility fracture.

CONCLUSIONS

This study revealed the LS severity to predicted fragility fractures. We suggested that the progression of LS associated with osteoporosis increases the fracture risk.

Automatic Spine Segmentation and Parameter Measurement for Radiological Analysis of Whole-Spine Lateral Radiographs Using Deep Learning and Computer Vision

Radiographic examination is essential for diagnosing spinal disorders, and the measurement of spino-pelvic parameters provides important information for the diagnosis and treatment planning of spinal sagittal deformities. While manual measurement methods are the golden standard for measuring parameters, they can be time consuming, inefficient, and rater dependent. Previous studies that have used automatic measurement methods to alleviate the downsides of manual measurements showed low accuracy or could not be applied to general films. We propose a pipeline for automated measurement of spinal parameters by combining a Mask R-CNN model for spine segmentation with computer vision algorithms. This pipeline can be incorporated into clinical workflows to provide clinical utility in diagnosis and treatment planning. A total of 1807 lateral radiographs were used for the training (n = 1607) and validation (n = 200) of the spine segmentation model. An additional 200 radiographs, which were also used for validation, were examined by three surgeons to evaluate the performance of the pipeline. Parameters automatically measured by the algorithm in the test set were statistically compared to parameters measured manually by the three surgeons. The Mask R-CNN model achieved an average precision at 50% intersection over union (AP50) of 96.2% and a Dice score of 92.6% for the spine segmentation task in the test set. The mean absolute error values of the spino-pelvic parameters measurement results were within the range of 0.4° (pelvic tilt) to 3.0° (lumbar lordosis, pelvic incidence), and the standard error of estimate was within the range of 0.5° (pelvic tilt) to 4.0° (pelvic incidence). The intraclass correlation coefficient values ranged from 0.86 (sacral slope) to 0.99 (pelvic tilt, sagittal vertical axis).

Impact of spinal sagittal malalignment on locomotive syndrome and physical function in community-dwelling middle aged and older women

BACKGROUND

Adult spinal deformity has a substantially debilitating effect on older people's physical and mental health. However, the impact of sagittal malalignment on locomotive syndrome (LS), sarcopenia, and physical function in community-dwelling older women has not yet been clarified. This study aimed to investigate the association between these factors in community-dwelling middle aged and older women.

METHODS

A total of 361 women were recruited from participants performing aquatic exercises in a rural area of Japan. The body mass index, skeletal muscle mass index, trunk muscle mass, spinal inclination angle (SIA), grip strength, timed up-and-go test (TUG), maximum stride of the participants, and one-leg standing time were measured. Low back pain (LBP)- and health-related quality of life (HRQOL) were evaluated using the Oswestry Disability Index (ODI) and the Short-Form 8 questionnaire. Associations between the global sagittal alignment using SIA and investigating parameters were analyzed.

RESULTS

The prevalence of sarcopenia was 3.6%. The prevalence of LS (stages 1, 2, and 3) was 43.8% (158 of 361), and the number of participants in each LS stage was 203 (stage 0), 95 (stage 1), 28 (stage 2), and 35 (stage 3). The SIA was significantly correlated with the 25-question geriatric locomotive function scale (r' = 0.292, p < 0.001), ODI (r' = 0.267, p < 0.001), and TUG (r' = 0.453, p < 0.001) after adjusting for age. In the receiver-operating characteristic curve analysis, the cutoff values of SIA for LS ≥ stage 2 and ODI ≥ 20% were 5°.

CONCLUSIONS

LBP-related QOL and physical performance were significantly associated with global sagittal alignment. Global sagittal alignment was correlated with the three-stage category of LS. The spinal inclination of 5° was a cutoff value to predict exacerbation of mobility function and HRQOL status.

The Analysis of Preoperative Roussouly Classification on Pain Scores and Radiological Data in Lateral Lumbar Interbody Fusion for Patients with Lumbar Degenerative Disease

STUDY DESIGN

A retrospective observational study.

OBJECTIVE

The type of sagittal profile defined by Roussouly has affected spinal degeneration and surgical outcome. This study aimed to investigate the effect of preoperative Roussouly classification on pain intensity and radiological data of patients with lumbar degenerative disease who underwent indirect decompression with lateral lumbar interbody fusion (LLIF).

METHODS

We retrospectively investigated 102 patients who underwent LLIF without direct decompression. Patients were subdivided into 4 groups according to the Roussouly classification determined from preoperative full-length and lateral spine X-rays, and classified according to Roussouly types I, II, and IV in the nonstandard group and Roussouly type III in the standard group.

RESULTS

The nonstandard group showed improved sagittal vertical axis and lumbar lordosis after LLIF surgery, but the midsagittal canal diameter and axial central canal area of the thecal sac using T2-weighted sagittal and axial magnetic resonance imaging were smaller than those in the standard group. On the other hand, each numeric rating scale score 1 year after surgery improved in all patients. Changes in numeric rating scale scores in low back pain, leg pain, and numbness were not statistically significant between Roussouly classification types.

CONCLUSIONS

These results suggest that the nonstandard group may have less indirect decompression effect from LLIF than the standard group. In the short term, we show for the first time after LLIF surgery that preoperative sagittal spinal alignment and the pelvic position may not significantly impact pain improvement.

What is the fate of the adjacent segmental angles 6 months after single-level L3-4 or L4-5 lateral lumbar interbody fusion?

BACKGROUND CONTEXT

Lateral lumbar interbody fusion (LLIF) is an effective technique for fusion and sagittal alignment correction/maintenance. Studies have investigated the impact on the segmental angle and lumbar lordosis (and pelvic incidence-lumbar lordosis mismatch), however not much is documented regarding the immediate compensation of the adjacent angles.

PURPOSE

To evaluate acute adjacent and segmental angle as well as lumbar lordosis changes in patients undergoing a L3-4 or L4-5 LLIF for degenerative pathology.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Patients included in this study were analyzed pre- and post-LLIF performed by one of three fellowship-trained spine surgeons, 6 months following surgery.

OUTCOME MEASURES

Patient demographics (including body mass index, diabetes diagnosis, age, and sex) as well as VAS and ODI scores were measured. Lateral lumbar radiograph parameters: lumbar lordosis (LL), segmental lordosis (SL), infra and supra-adjacent segmental angle, and pelvic incidence (PI).

METHODS

Multiple regressions were applied for the main hypothesis tests. We examined any interactive effects at each operative level and used the 95% confidence intervals to determine significance: a confidence interval excluding zero indicates a significant effect.

RESULTS

We identified 84 patients who underwent a single level LLIF (61 at L4-5, 23 at L3-4). For both the overall sample and at each operative level, the operative segmental angle was significantly more lordotic postop compared to preop (all ps≤.01). Adjacent segmental angles were significantly less lordotic postop compared to pre-op overall (p=.001). For the overall sample, greater lordotic change at the operative segment led to more compensatory reduction of lordosis at the supra-adjacent segment. At L4-5, more lordotic change at the operative segment led to more compensatory lordosis reduction at the infra-adjacent segment.

CONCLUSION

The present study demonstrated that LLIF resulted in significant increase in operative level lordosis and a compensatory decrease in supra- and infra-adjacent level lordosis, and subsequently no significant impact on spinopelvic mismatch.

Focusing on the amount of immediate changes in spinopelvic radiographic parameters to predict the amount of mid-term improvement of quality of life in adult degenerative scoliosis patients with surgery

INTRODUCTION

Surgery is still an effective treatment option for adult degenerative scoliosis (ADS), but how to predict patients' significant amount of the improvement in quality of life remains unclear. The previous studies included an inhomogeneous population. This study aimed to report the results about concentrating on the amount of immediate changes in spinopelvic radiographic parameters to predict the amount of mid-term improvement in quality of life in ADS patients.

MATERIALS AND METHODS

Pre-operative and immediately post-operative radiographic parameters included Cobb angle, coronal vertical axis (CVA), sagittal vertical axis (SVA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI) and LL/PI matching (PI-LL). Quality of life scores were evaluated pre-operatively and at the final follow-up using Oswestry Disability Index (ODI) and visual analogue scale (VAS). The amount of immediate changes in spinopelvic radiographic parameters (Δ) and the amount of mid-term improvement in quality of life (Δ) were defined, respectively.

RESULTS

Patients showed significant change in radiographic parameters, ODI and VAS pre- and post-surgery, except CVA and PI. Univariate analysis showed a significant correlation between ΔTK, ΔLL, ΔCVA and the amount of mid-term improvement in quality of life, but multivariate analysis did not get a significant result. Univariate and multivariate analyses showed that ΔSVA was still a significant predictor of ΔVAS and ΔODI. The changes in the other radiographic parameters were not significant. The equations were developed by linear regression: ΔODI = 0.162 × ΔSVA - 21.592, ΔVAS = 0.034 × ΔSVA - 2.828. In the ROC curve for ΔSVA in the detection of a strong ΔODI or ΔVAS, the cut-off value of ΔSVA was - 19.855 mm and - 15.405 mm, respectively.

CONCLUSIONS

This study shows that ΔSVA can predict the amount of mid-term improvement in quality of life in ADS patients. The changes in the other radiographic parameters were not significant. Two equations were yielded to estimate ΔODI and ΔVAS. ΔSVA has respective cut-off value to predict ΔODI and ΔVAS.

Clinical Results of 10-mm Endoscopic Minimally Invasive Interlaminar Decompression in the Treatment of Lumbar Spinal Stenosis with Degenerative Lumbar Scoliosis and Simple Lumbar Spinal Stenosis

Purpose

The number of patients with lumbar spinal stenosis (LSS) with degenerative lumbar scoliosis (DLS) is gradually increasing as the population ages. The purpose of this study was to evaluate the clinical outcomes of 10-mm endoscopic minimally invasive interlaminar decompression for LSS with DLS and simple LSS.

Material and Methods

The clinical data of 175 consecutive elderly patients with LSS were retrospectively analyzed. They were divided into LSS group and LSS with DLS group based on whether they were accompanied by DLS. Patient demographics, perioperative indicators, and clinical outcomes were recorded. Lumbar spine stability was assessed by imaging data. Meanwhile, visual analog scale (VAS) scores, Oswestry Disability Index (ODI) scores, and the modified Macnab criteria were used to assess clinical outcomes.

Results

There were 129 patients in the LSS group and 46 patients in the LSS with DLS group. Both groups had similar VAS and ODI scores preoperatively, and both were significantly lower postoperatively (P < 0.05). However, patients combined with DLS showed higher VAS scores for low back pain at 3 months and 1 year postoperatively (P < 0.05). In addition, postoperative LL and PI-LL were significantly improved in both groups (P < 0.05). However, patients in LSS with DLS group showed higher PT, PI and PI-LL before and after surgery. According to the modified Macnab criteria, the excellent and good rates were 92.25% and 89.13% in the LSS group and LSS with DLS group at the last follow-up, respectively.

Conclusion

10-mm endoscopic minimally invasive interlaminar decompression for LSS with or without DLS has shown satisfactory clinical outcomes. However, patients with DLS may have higher residual low back pain after surgery.

Association of Various Spinopelvic Parameters and the Quality of Life in Those With Degenerative Lumbar Scoliosis in the Indian Population

Purpose The current study aimed to find any association between various spinopelvic parameters and the quality of life in patients with degenerative lumbar scoliosis (DLS) measured as per the Oswestry disability index (ODI) and visual analog scale (VAS) in the Indian population. Methods We included 20 DLS patients of more than 40 years with a Cobb angle of more than 10° and without any trauma, tumour, infection, or congenital scoliosis presented in our tertiary care centre in the study. The VAS and ODI were calculated for each patient. Radiological parameters were recorded for every patient, including sagittal balance, coronal balance, Cobb angle, pelvic incidence, pelvic tilt, and lumbar lordotic angle. We evaluated the results and sought any association between clinical and radiological variables for DLS. Results Patients with positive sagittal balance had significantly higher disability than those with neutral sagittal balance (p-value 0.007). Furthermore, patients with coronal imbalance had more severe pain (p-value 0.013) and disability (p-value 0.038) than those with neutral coronal balance. We also found that the ODI and VAS were not associated with any other spinopelvic parameters. Conclusion From the present study, we can conclude that in the Indian population, both positive sagittal and coronal imbalances are associated with poor functional status in patients with DLS. Therefore, while planning surgical correction for these patients, both coronal and sagittal balance are important and need to be considered.

Utility of Expandable Interbody Cages in Open Transforaminal Interbody Fusions: A Comparison With Static Cages

Background Expandable interbody cages, while popular in minimally invasive fusions due to their slim profile and increased ease of insertion, have not been widely explored in open surgery. The benefits of expandable cages may also extend to open fusions through their potential to achieve a greater restoration of lumbar lordosis while minimizing intraoperative complications. To highlight these benefits, we present a case series of adult spinal deformity (ASD) patients treated with an open transforaminal lumbar interbody fusion (TLIF) using expandable cages and compare outcomes to those of patients treated with static cages from the literature. Methods A retrospective cohort study of patients who underwent a deformity correction procedure and TLIF with expandable interbody cages at Brigham and Women's Hospital between 2018 and 2022 was conducted. Patient demographics, complications, and pre- and postoperative radiographic parameters of spinopelvic alignment were collected. A literature search was completed to identify studies employing static cages. T-tests were performed to compare postoperative changes in radiographic parameters by cage type. Results Forty-five patients (mean age of 62.6 years) with an average of 2.1 cages placed met the inclusion criteria. Patients experienced five intraoperative complications and 23 neurologic deficits (from minor to major), while nine patients required a revision operation. Lumbar lordosis increased by 9.8° ± 14.5° (p < 0.0001), the sagittal vertical axis (SVA) decreased by 25.5 mm ± 56.7 mm (p = 0.0048), and pelvic incidence-lumbar lordosis mismatch decreased by 13.3° ± 17.5° (p < 0.0001) with the use of expandable cages. Expandable cages yielded similar changes in lumbar lordosis to 15° and 8° cages but improved the lumbar lordosis generated from rectangular and 4° cages. When compared to static cages, expandable cages mildly reduced intraoperative complications. Conclusions Expandable interbody cages are an effective means of restoring spinopelvic alignment in ASD that have the potential to improve patient outcomes in open fusions compared to standard static cages. Especially when compared to rectangular and 4° static cages, expandable cages provide a clear benefit in the correction of lumbar lordosis. The impact of open spinal fusions with expandable cages on outcomes should continue to be explored in other cohorts.

Bone microstructure and volumetric bone mineral density in patients with global sagittal malalignment

PURPOSE

Sagittal spinal malalignment often leads to surgical realignment, which is associated with major complications. Low bone mineral density (BMD) and impaired bone microstructure are risk factors for instrumentation failure. This study aims to demonstrate differences in volumetric BMD and bone microstructure between normal and pathological sagittal alignment and to determine the relationships among vBMD, microstructure, sagittal spinal and spinopelvic alignment.

METHODS

A retrospective, cross-sectional study of patients who underwent lumbar fusion for degeneration was conducted. The vBMD of the lumbar spine was assessed by quantitative computed tomography. Bone biopsies were evaluated using microcomputed tomography (μCT). C7-S1 sagittal vertical axis (SVA; ≥ 50 mm malalignment) and spinopelvic alignment were measured. Univariate and multivariable linear regression analysis evaluated associations among the alignment, vBMD and μCT parameters.

RESULTS

A total of 172 patients (55.8% female, 63.3 years, BMI 29.7 kg/m2, 43.0% with malalignment) including N = 106 bone biopsies were analyzed. The vBMD at levels L1, L2, L3 and L4 and the trabecular bone (BV) and total volume (TV) were significantly lower in the malalignment group. SVA was significantly correlated with vBMD at L1-L4 (ρ = -0.300, p < 0.001), BV (ρ = - 0.319, p = 0.006) and TV (ρ = - 0.276, p = 0.018). Significant associations were found between PT and L1-L4 vBMD (ρ = - 0.171, p = 0.029), PT and trabecular number (ρ = - 0.249, p = 0.032), PT and trabecular separation (ρ = 0.291, p = 0.012), and LL and trabecular thickness (ρ = 0.240, p = 0.017). In the multivariable analysis, a higher SVA was associated with lower vBMD (β = - 0.269; p = 0.002).

CONCLUSION

Sagittal malalignment is associated with lower lumbar vBMD and trabecular microstructure. Lumbar vBMD was significantly lower in patients with malalignment. These findings warrant attention, as malalignment patients may be at a higher risk of surgery-related complications due to impaired bone. Standardized preoperative assessment of vBMD may be advisable.

Is coronal imbalance in degenerative lumbar scoliosis patients associated with the number of degenerated discs? A retrospective imaging cross-sectional study

BACKGROUND

Degenerative lumbar scoliosis (DLS) is a common degenerative disease of the spine, that predominates in the elderly, and causes spinal deformities along with severe pain and reduced quality of life. The relationship between DLS and degenerated discs is now a new direction of research. Our study aimed to the relationship between the imaging parameters of coronal imbalance and the number of degenerated discs in patients with degenerative lumbar scoliosis and analyzed the segmental distribution of the degenerated discs in patients with DLS.

METHODS

We performed a retrospective analysis of the imaging of 40 patients who met the inclusion criteria who attended our outpatient clinic between April 2021 and July 2021, measuring the intervertebral space height of the AV (high side and low side), Cobb angle, and AVT (Apical vertebral translation) from coronal X-ray. Degenerated discs were evaluated by the Pfirrmann score based on T2-weighted magnetic resonance images. We record the number of degenerated discs (Graded as Grade III, Grade IV or Grade V by the Pfirrmann score) and the segments in which they are located. Finally, we explore the relationship between the imaging parameters of coronal imbalance and the number of degenerated discs in patients with DLS.

RESULT

Among the 40 patients with DLS in our study, all patients had degenerated discs in the lumbar spine, 95% of patients had degenerated discs(Pfirrmann score Grade III, Grade IV or Grade V) in 2 or more segments, with the L4-L5 segment being the most involved segment with the most degenerated discs, followed by the L3-L4 segment and the L5-S1 segment. There was no statistically significant relationship between the number of degenerated discs and the coronal imbalance in patients with DLS.

CONCLUSION

Our results showed an association between DLS and degenerated discs, but there was no statistically significant relationship between imbalance in the coronal plane of the lumbar spine and the number of degenerated discs in patients with DLS. The distribution of degenerated disc segments in patients with DLS showed a higher likelihood of disc degeneration in 2 or more segments, and a higher frequency of disc degeneration in the inferior disc and in the adjacent segments of the AV.

Isokinetic strength assessment of trunk muscle and its relationship with spinal-pelvic parameters in patients with degenerative spinal deformity

BACKGROUND

The incidence rate of degenerative spinal deformity (DSD) has gradually increased in the elderly. Currently, the relationship between the functional status of trunk muscle and the spinal-pelvic parameters of DSD patients remains unclear.

OBJECTIVE

This paper aims to explore the relationship between the two factors and provide new clues for exploring the mechanism of the occurrence and development of DSD.

METHODS

A total of 41 DSD patients treated in our hospital (DSD group) and 35 healthy volunteers (control group) were selected. Muscle strength was evaluated using an IsoMed-2000 isokinetic dynamometer, and the trunk flexor and extensor peak torque (PT) of subjects was measured at a low, medium, and high angular velocity of 30∘/s, 60∘/s, and 120∘/s, respectively. Hand grip strength (HGS) was assessed using an electronic grip dynamometer and Surgimap software was used to measure the spinal-pelvic parameters, including the sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence rate (PI), and PI-LL, and the relationship between trunk muscle function and various parameters was analyzed.

RESULTS

Under the three angular velocities, the flexor and extensor PT values in the DSD group were lower than those in the control group, and only the extensor PT showed a statistically significant difference (P< 0.05). There was no significant difference in HGS between the two groups (P> 0.05). In the DSD group, the extensor PT at 30∘/s was significantly negatively correlated with SVA (P< 0.05). At 60∘/s and 120∘/s, the extensor PT was significantly negatively correlated with SVA and PT (P< 0.05).

CONCLUSION

Trunk extensor strength is significantly lower in DSD patients than in normal controls. The decline in trunk extensor strength in DSD patients is a type of local muscle dysfunction more closely related to the deformity, which is likely involved in the compensatory mechanism of DSD and may reflect the overall imbalance of the trunk.

Association Between the Bone Density of Posterior Fusion Mass and Mechanical Complications After Thoracolumbar Three-Column Osteotomy for Adult Spinal Deformity

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

To assess the relationship of fusion mass bone density on computed tomography (CT) and the development of rod fractures (RFs) and proximal junctional kyphosis (PJK).

SUMMARY OF BACKGROUND DATA

Few studies have evaluated the relationship of fusion mass bone density to mechanical complications.

MATERIALS AND METHODS

A retrospective review of adult spinal deformity patients who underwent thoracolumbar three-column osteotomy from 2007 to 2017 was performed. All patients underwent routine 1-year CT imaging and had at least 24 months follow-up. Posterior fusion mass bone density was evaluated by measuring hounsfield unit (HU) on CT in three different regions [upper instrumented vertebra (UIV), lower instrumented vertebra, and osteotomy site], and were compared between patients with and without mechanical complications.

RESULTS

A total of 165 patients (63.2 years, 33.5% male) were included. Overall PJK rate was 18.8%, and 35.5% of these underwent PJK revision. There was significantly lower density of posterior fusion mass at the UIV in patients who experienced PJK compared with patients without PJK (431.5HU vs. 537.4HU, P =0.026). Overall RF rate was 34.5% and 61.4% of these underwent revision for RFs. Among 57 patients with RFs, 71.9% had pseudarthrosis. Fusion mass density did not differ between patients with or without RFs. However, in RF patients with pseudarthrosis, there was significantly higher bone mass density near the osteotomy compared with those without pseudarthrosis (515.7HU vs. 354.2HU, P =0.012). There were no differences in radiographic sagittal measures between the patients with and without RF or PJK.

CONCLUSIONS

Patients with PJK tend to have less dense posterior fusion mass at the UIV. Fusion mass density does not correlate with RF, but greater bone density near the osteotomy was correlated with accompanying pseudarthrosis in patients with RFs. Assessing density of posterior fusion mass on CT may be helpful in assessing risk for PJK and provide insight as to the causes of RFs.

Prediction formulae of sagittal alignment in thoracolumbar kyphosis secondary to ankylosing spondylitis after osteotomy

To construct and validate prediction formulae of sagittal alignment in thoracolumbar kyphosis secondary to ankylosing spondylitis (AS) after osteotomy. A total of 115 AS patients who suffered from thoracolumbar kyphosis and underwent osteotomy were enrolled, with 85 patients in derivation group and 30 patients in validation group. Radiographic parameters were measured on lateral radiographs, including thoracic kyphosis, lumbar lordosis (LL), T1 pelvic angel (TPA), sagittal vertical axis (SVA), osteotomized vertebral angle, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and PI and LL mismatch (PI-LL). Prediction formulae of SS, PT, TPA and SVA were established; and their effectiveness was evaluated. There was no significant difference in baseline characteristics between the two groups (p > 0.05). In derivation group, LL and PI-LL were correlated with SS, and were then used to establish the prediction formula of SS[SS = - 12.791-0.765 × (LL) + 0.357 × (PI-LL), R² = 68.3%]; PI and PI-LL were correlated with PT, and the prediction formula of PT were thus established[PT = 12.108 + 0.402 × (PI-LL) + 0.252 × (PI), R² = 56.8%]; PT, PI-LL and LL were correlated with TPA, and were used to establish the prediction formula of TPA[TPA = 0.225 + 0.597 × (PT) + 0.464 × (PI-LL)-0.161 × (LL), R² = 87.4%]; PT, PI-LL and age were correlated with SVA, and were used to establish the prediction formula of SVA[SVA = 36.157 + 2.790 × (PI-LL) + 1.657 × (Age)-1.813 × (PT), R² = 41.5%]. In validation group, the predictive SS, PT, TPA and SVA were basically consistent with corresponding real values; and the mean error between predictive values and real values was of 1.3° in SS, 1.2° in PT, 1.1° in TPA and 8.6 mm in SVA. Postoperative SS, PT, TPA and SVA could be predicted with PI and the planned LL and PI-LL using prediction formulae, providing a method for AS kyphosis to plan postoperative sagittal alignment. Change of pelvic posture after osteotomy was quantitatively evaluated using the formulae.

Spino-pelvic radiological parameters: Comparison of measurements obtained by radiologists using the traditional method versus spine surgeons using a semi-automated software (Surgimap)

Background

Spinopelvic balance measurement is a key point to get an appropriate diagnosis and treatment in a group of spine pathologies; thus, it seems necessary the evaluation of different methods for obtaining the most reliable values. For that reason, different automatic and semi-automatic computer-assisted tools have been developed, and one example of them is Surgimap.

Purpose

To demonstrate that the sagittal balance measurements with Surgimap are equal and more time-efficient than with Agfa-Enterprise.

Material and Methods

Retrospective-prospective study. Biased comparative analysis of radiographic measurements performed on two different occasions (96 h interval), between two spine surgeons using Surgimap and two radiologists using the traditional Cobb method (TCM) with the Agfa-Enterprise program in 36 full spine lateral X-ray, determining inter- and intra-observer reliability and the mean time required to obtain the measurements.

Results

Measurements with both methods demonstrated an excellent intra-observer correlation (Surgimap: PCC 0.95 [0.85-0.99]; TCM: PCC 0.90 [0.81-0.99]). Inter-observer correlation also demonstrated an excellent relationship (PCC >0.95). Thoracic kyphosis (TK) demonstrated the lowest levels of inter-observer correlation (PCC: 0.75). The average time in seconds with TCM was 154.6, while with the Surgimap it was 41.8 s.

Conclusion

Surgimap proved to be equally reliable and 3.5 times faster. Therefore, in consistency with the available literature, our results would allow us to promote the use of Surgimap as a clinical diagnostic tool considering precision and efficiency.

Lumbar Lordosis Distribution in Asymptomatic Adult Volunteers: A Systematic Review

Background

Restoring lumbar lordosis is important for adult spinal deformity surgery. Several reports have suggested that lumbar lordosis distribution has a significant impact on the outcome of surgery, including lumbar distribution index (LDI), proximal lumbar lordosis (PLL), and distal lumbar lordosis (DLL). The features of lumbar lordosis distribution are inconclusive in asymptomatic adults.

Questions/Purposes

We sought to evaluate the variation of lumbar lordosis distribution (LDI, PLL, and DLL) and to identify associated factors in asymptomatic adult volunteers.

Methods

We performed a systematic review of the Embase and Medline databases to identify studies in asymptomatic adult volunteers to evaluate lumbar lordosis distribution including LDI, PLL, and DLL.

Results

Twelve articles met eligibility criteria and were included in our review. The respective pooled estimates of mean and variance, respectively, were 65.10% (95% confidence interval [CI]: 62.61-67.58) and 13.70% in LDI, 16.51° (95% CI: 5.54-27.49) and 11.46° in PLL, and 35.47° (95% CI: 32.79-38.18) and 9.10° in DLL. Lumbar lordosis distribution was associated with race, age, sex, body mass index, pelvic incidence, and Roussouly classification.

Conclusions

This systematic review found that despite a wide variation in LDI and PLL, DLL is maintained in a narrower range in asymptomatic adult volunteers, especially in white populations. Distal lumbar lordosis may be a more reliable radiographic parameter to restore the lumbar lordosis distribution in preoperative planning.

The association of rod curvature with postoperative outcomes in patients undergoing posterior lumbar interbody fusion for spinal stenosis: a retrospective case-control study

BACKGROUND

Restoration of sagittal balance is a crucial consideration in posterior lumbar interbody fusion (PLIF) surgery and adverse postoperative outcomes are associated with inadequate restoration of sagittal alignment. However, there remains a shortage of substantial evidence regarding the effect of rod curvature on both sagittal spinopelvic radiographic parameters and clinical outcomes.

METHOD

A retrospective case-control study was conducted in this study. Patient demographics (age, gender, height, weight and BMI), surgical characteristics (number of fused levels, surgical time, blood loss and hospital stay) and radiographic parameters (lumbar lordosis [LL], sacral slope [SS], pelvic incidence [PI], pelvic tilt [PT], PI-LL, Cobb angle of fused segments [Cobb], rod curvature [RC], Posterior tangent angle of fused segments [PTA] and RC-PTA) were analyzed.

RESULTS

Patients in the abnormal group had older mean age and suffered more blood loss than those in the normal group. In addition, RC and RC-PTA were significantly lower in the abnormal group compared to the normal group. Multivariate regression analysis revealed that lower age (OR = 0.94; 95% CI: 0.89-0.99; P = 0.0187), lower PTA (OR = 0.91; 95% CI: 0.85-0.96; P = 0.0015) and higher RC (OR = 1.35; 95% CI: 1.20-1.51; P < 0.0001) were related to higher odds of better surgical outcomes. The receiver operating characteristic curve analysis showed that the ROC curve (AUC) for predicting outcomes of surgery by RC classifier was 0.851 (0.769-0.932).

CONCLUSIONS

In patients who underwent PLIF surgery for lumbar spinal stenosis, those who had a satisfactory postoperative outcome tended to be younger, had lower blood loss, and higher values of RC and RC-PTA compared to those who had poor recovery and required revision surgery. Additionally, RC was found to be a reliable predictor of postoperative outcomes.

Clinical Validation of a Novel Musculoskeletal Modeling Framework to Predict Postoperative Sagittal Alignment

STUDY DESIGN

A retrospective radiographic and biomechanical analysis of 108 thoracolumbar fusion patients from two clinical centers.

OBJECTIVE

This study aimed to determine the validity of a computational framework for predicting postoperative patient posture based on preoperative imaging and surgical data in a large clinical sample.

SUMMARY OF BACKGROUND DATA

Short-term and long-term studies on thoracolumbar fusion patients have discussed that a preoperative predictive model would benefit surgical planning and improve patient outcomes. Clinical studies have shown that postoperative alignment changes at the pelvis and intact spine levels may negatively affect postural balance and quality of life. However, it remains challenging to predict such changes preoperatively because of confounding surgical and patient factors.

MATERIALS AND METHODS

Patient-specific musculoskeletal models incorporated weight, height, body mass index, age, pathology-associated muscle strength, preoperative sagittal alignment, and surgical treatment details. The sagittal alignment parameters predicted by the simulations were compared with those observed radiographically at a minimum of three months after surgery.

RESULTS

Pearson correlation coefficients ranged from r=0.86 to 0.95, and mean errors ranged from 4.1° to 5.6°. The predictive accuracies for postoperative spinopelvic malalignment (pelvic incidence minus lumbar lordosis>10°) and sagittal imbalance parameters (TPA>14°, T9PA>7.4°, or LPA>7.2°) were between 81% and 94%. Patients treated with long fusion (greater than five segments) had relatively lower prediction errors for lumbar lordosis and spinopelvic mismatch than those in the local and short groups.

CONCLUSIONS

The overall model performance with long constructs was superior to those of the local (one to two segments) and short (three to four segments) fusion cases. The clinical framework is a promising tool in development to enhance clinical judgment and to help design treatment strategies for predictable surgical outcomes.

LEVEL OF EVIDENCE

3.

Total knee arthroplasty in patients with lumbar spinal fusion leads to significant changes in pelvic tilt and sacral slope

BACKGROUND

The knee-hip-spine syndrome has been well elucidated in the literature in recent years. The aim of this study was to evaluate the effect of total knee arthroplasty (TKA) on spinopelvic sagittal alignment in patients with and without pre-TKA lumber spinal fusion.

METHODS

This is a retrospective cohort study of 113 patients who underwent TKA for primary osteoarthritis. Patients were stratified into the following three groups: (1) patients who had pre-TKA spinal fusion (SF, n = 19), (2) patients who had no spinal fusion but experienced pre-TKA flexion contracture (FC, n = 20), and (3) patients without flexion contracture or spinal fusion before TKA (no SF/FC, n = 74). Spinopelvic sagittal alignment parameters, including pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), and plumb line-sacrum distance (SVA) were measured preoperatively and 3 months postoperatively on lateral standing full-body low-dose images.

RESULTS

TKA resulted in significant pre- to postoperative changes in pelvic tilt (average ∆ PT = - 8.6°, p = 0.018) and sacral slope (average ∆ SS = 8.6°, p = 0.037) in the spinal fusion (SF) group. Non-significant changes in spinopelvic sagittal alignment parameters (PT, SS, LL, TK, SVA) were noted postoperatively in all patients in the FC and the no SF/FC groups.

CONCLUSIONS

TKA can lead to meaningful changes in spinopelvic alignment in patients with prior lumbar fusion compared to those without spinal fusion. Patients with spinal fusion who are candidates for both hip and knee replacements should consider undergoing TKA first since changes in spinopelvic sagittal alignment can increase the risk of future complications.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Relationship between lumbar lordosis, pelvic parameters, PI-LL mismatch and outcome after short fusion surgery for lumbar degenerative disease. Literature review, rational and presentation of public study protocol: RELApSE study (registry for evaluation of lumbar artrodesis sagittal alignEment)

Background

Vertebral arthrodesis for degenerative pathology of the lumbar spine still remains burdened by clinical problems with significant negative results. The introduction of the sagittal balance assessment with the evaluation of the meaning of pelvic parameters and spinopelvic (PI-LL) mismatch offered new evaluation criteria for this widespread pathology, but there is a lack of consistent evidence on long-term outcome.

Methods

The authors performed an extensive systematic review of literature, with the aim to identify all potentially relevant studies about the role and usefulness of the restoration or the assessment of Sagittal balance in lumbar degenerative disease. They present the study protocol RELApSE (NCT05448092 ID) and discuss the rationale through a comprehensive literature review.

Results

From the 237 papers on this topic, a total of 176 articles were selected in this review. The analysis of these literature data shows sparse and variable evidence. There are no observations or guidelines about the value of lordosis restoration or PI-LL mismatch. Most of the works in the literature are retrospective, monocentric, based on small populations, and often address the topic evaluation partially.

Conclusions

The RELApSE study is based on the possibility of comparing a heterogeneous population by pathology and different surgical technical options on some homogeneous clinical and anatomic-radiological measures aiming to understanding the value that global lumbar and segmental lordosis, distribution of lordosis, pelvic tilt, and PI-LL mismatch may have on clinical outcome in lumbar degenerative pathology and on the occurrence of adjacent segment disease.

Sagittal alignment cut-off values for predicting future fall-related fractures in community-dwelling osteoporotic women

PURPOSE

Determining the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures is essential for understanding fracture risk and informing clinicians and physical therapists. We determined the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures in this study.

METHODS

In the retrospective cohort study, we enrolled a total of 255 women aged ≥ 65 years who visited an outpatient osteoporosis clinic. We measured participants' bone mineral density and sagittal alignment, including sagittal vertical axis (SVA), pelvic tilt, thoracic kyphosis, pelvic incidence, lumbar lordosis, global tilt, and gap score at the initial visit. The cut-off value for sagittal alignment that was significantly associated with fall-related fractures was calculated after using multivariate Cox proportional hazards regression analysis.

RESULTS

Ultimately, 192 patients were included in the analysis. After a mean follow-up of 3.0 years, 12.0% (n = 23) had fractures due to falls. Multivariate Cox regression analysis confirmed that SVA (hazard ratio [HR] = 1.022, 95% confidence interval [CI] = 1.005-1.039) was the only independent predictor of fall-related fracture occurrence. The predictive ability of SVA for the occurrence of fall-related fractures was moderate (area under the curve [AUC] = 0.728, 95% CI = 0.623-0.834), with a cut-off value of 100 mm for SVA. SVA classified by cut-off value was also associated with an increased risk of developing fall-related fractures (HR = 17.002, 95% CI = 4.102-70.475).

CONCLUSION

We found that assessing the cut-off value of sagittal alignment would be useful information in understanding fracture risk in postmenopausal older women.

Postoperative change in lumbopelvic alignment after short-segment transforaminal lumbar interbody fusion is related to preoperative postural difference in lumbar lordosis

BACKGROUND

Postoperative changes in lumbar lordosis (LL) after transforaminal lumbar interbody fusion (TLIF) and the related factors are not well-understood. Recently, the preoperative difference in LL between standing and supine positions (DiLL) was proposed as a factor for predicting postoperative radiologic outcomes after short-segment TLIF. This study investigated the influence of DiLL on mid-term radiological outcomes after short-segment TLIF.

METHODS

Sixty-six patients with lumbar degenerative disease treated with short-segment TLIF (1-2 levels) who underwent lumbar spine standing radiographs at 3 months, 6 months, 1 year, 2 years, 3 years, 4 years, and 5 years postoperatively were divided into DiLL (+) and DiLL (-) groups (preoperative DiLL ≥0° and <0°, respectively). Associations between the postoperative change in LL and DiLL and clinical outcomes (Oswestry disability index (ODI) and Nakai score) were evaluated.

RESULTS

Temporary restoration of LL (+4.5°) until 1 year postoperatively and a subsequent decrease in LL from 1 to 5 years postoperatively (-5.3°) was observed in the DiLL (+) group. No postoperative change in LL was observed in the DiLL (-) group. Postoperative changes in LL were mainly observed in non-fused segments. The postoperative change in LL (ΔLL) until 1 year postoperatively had a significant positive association with DiLL (p = 0.00028), whereas ΔLL from 1 to 5 years postoperatively showed a significant negative association with DiLL (p = 0.010) and a positive association with Nakai score (p = 0.028). ΔLL until 5 years postoperatively showed a significant positive association with postoperative ODI improvement (p = 0.011).

CONCLUSIONS

DiLL (+) patients showed a specific time course with temporary LL restoration until 1 year postoperatively and a subsequent decrease in LL from 1 to 5 years postoperatively. Patients with larger postoperative increase in LL until 5 years postoperatively and lesser decrease in LL from 1 to 5 years postoperatively tended to show better mid-term clinical outcomes.

The association of dynamic spinal alignment on gait endurance of patients with adult spinal deformity: a cross-sectional study

PURPOSE

The purpose of this study was to evaluate the gait posture of patients with adult spinal deformity (ASD) using a 3-dimensional motion analysis system (3DMAS) and to investigate whether it affects gait endurance.

METHODS

Fifty-one patients with ASD aged 50 years or older who were admitted to our hospital between March 2016 and March 2018 were included in the study. The subjects completed the 6-min walking test, which is an indicator of gait endurance. Static standing posture was assessed by whole-spine x-ray examination (coronal cobb angle, CCA; sagittal vertical axis, SVA; pelvic tilt, PT; and pelvic incidence minus lumbar lordosis, PI-LL). In addition, the gait posture was evaluated by a 3DMAS (dynamic trunk tilt angle, DTA; and dynamic pelvic tilt angle, DPA). The relationship between standing and gait postures and gait endurance was investigated by multivariable analysis.

RESULTS

In univariable analysis, SVA, PI-LL, and DTA were associated with gait endurance. Furthermore, in the multivariable analysis, DTA showed the strongest association among the static and dynamic parameters (R² = 0.61, β = - 0.35, P < 0.05).

CONCLUSIONS

An association was found between gait posture and gait endurance in patients with ASD. These findings can be useful to health care providers treating patients with ASD. It is advisable to assess the gait posture of patients with ASD because they present postural abnormalities during gait.

Use of the Global Alignment and Proportion score to predict postoperative health-related quality of life in adult spinal deformity surgery

OBJECTIVE

The purpose of this study was to validate the Global Alignment and Proportion (GAP) score as a predictor of health-related quality of life (HRQOL) outcomes for patients undergoing adult spinal deformity (ASD) surgery.

METHODS

This was a retrospective cohort study of patients with ASD undergoing long-segment spine fusions (≥ 5 vertebrae fused) at a single institution over a 2-year period (n = 85). Radiographic parameters were measured at preoperative, 6-week postoperative, 1-year postoperative, and 2-year postoperative visits. GAP scores were calculated using 4 sagittal parameters: relative pelvic version, relative lumbar lordosis, lordosis distribution index, and relative spinopelvic alignment. Patients were stratified into 3 GAP categories at each time point: proportioned (score 0-2), moderately disproportioned (score 3-6), and severely disproportioned (score ≥ 7). HRQOL outcomes were collected at preoperative, 1-year postoperative, and 2-year postoperative visits; these measures included patient self-reported outcome measures (i.e., PROMIS), Scoliosis Research Society-22 spinal deformity questionnaire (SRS-22), and Oswestry Disability Index (ODI) scores.

RESULTS

Overall, 42% of cases were revision surgeries and 96.5% of patients underwent fusion to the sacrum. The mean preoperative GAP score significantly improved from preoperative (7.84) to immediate postoperative (3.31) assessment (p < 0.001). Similarly, the percentage of patients categorized as proportioned improved from 9.4% at preoperative to 45.9% at immediate postoperative evaluation. The preoperative GAP score or category was not significantly associated with any preoperative HRQOL outcome metrics. The immediate postoperative GAP score was not correlated with any 1-year HRQOL outcomes. However, the immediate postoperative GAP score was significantly associated with 2-year SRS-22 outcomes, including SRS-22 function (r = -0.35, p < 0.01), self-image (r = -0.27, p = 0.044), and subtotal (r = -0.35, p < 0.01) scores. As compared to severely disproportioned patients, proportioned patients had better SRS-22 pain (4.08 vs 3.17, p = 0.04), satisfaction (4.40 vs 3.50, p = 0.02), and subtotal (4.01 vs 3.27, p = 0.036) scores. The immediate postoperative GAP score was also significantly associated with 2-year PROMIS outcomes, including PROMIS pain (r = 0.31, p = 0.023) and physical function (r = -0.35, p < 0.01) scores. As compared to severely disproportioned patients, proportioned patients had better PROMIS pain (53.18 vs 63.60, p = 0.025) and physical function (41.66 vs 34.18, p = 0.017) scores. Postoperative GAP score or category did not predict any ODI outcomes.

CONCLUSIONS

The postoperative GAP score is a predictor of long-term HRQOL outcomes following ASD surgery, and proportioned patients are more likely to have less pain and be satisfied with their surgery. However, the postoperative GAP score does not predict outcomes as measured by ODI.

Accuracy of Rod Contouring to Desired Angles With and Without a Template: Implications for Achieving Desired Spinal Alignment and Outcomes

STUDY DESIGN

Biomechanical Study.

OBJECTIVE

The search for optimal spinal alignment has led to the development of sophisticated formulas and software for preoperative planning. However, preoperative plans are not always appropriately executed since rod contouring during surgery is often subjective and estimated by the surgeon. We aimed to assess whether rods contoured to specific angles with a French rod bender using a template guide will be more accurate than rods contoured without a template.

METHODS

Ten experienced spine surgeons were requested to contour two 125 × 5.5 mm Ti64 rods to 40°, 60° and 80° without templates and then 2 more rods using 2D metallic templates with the same angles. Rod angles were then measured for accuracy and compared.

RESULTS

Average angles for rods bent without a template to 40°, 60° and 80° were 60.2°, 78.9° and 97.5°, respectively. Without a template, rods were overbent by a mean of 18.9°. When using templates of 40°, 60° and 80°, mean bend angles were 41.5°, 59.1° and 78.7°, respectively, with an average underbend of 0.2°. Differences between the template and non-template groups for each target angle were all significant (p < 0.001).

CONCLUSIONS

Without the template, surgeons tend to overbend rods compared to the desired angle, while surgeons improved markedly with a template guide. This tendency to overbend could have significant impact on patient outcomes and risk of proximal junctional failure and warrants further research to better enable surgeons to more accurately execute preoperative alignment plans.