Reference Data for Diagnosis of Spondylolisthesis and Disc Space Narrowing Based on NHANES-II X-rays

Robust reference data, representing a large and diverse population, are needed to objectively classify measurements of spondylolisthesis and disc space narrowing as normal or abnormal. The reference data should be open access to drive standardization across technology developers. The large collection of radiographs from the 2nd National Health and Nutrition Examination Survey was used to establish reference data. A pipeline of neural networks and coded logic was used to place landmarks on the corners of all vertebrae, and these landmarks were used to calculate multiple disc space metrics. Descriptive statistics for nine SPO and disc metrics were tabulated and used to identify normal discs, and data for only the normal discs were used to arrive at reference data. A spondylolisthesis index was developed that accounts for important variables. These reference data facilitate simplified and standardized reporting of multiple intervertebral disc metrics.

Management of Low and High Grades Spondylolisthesis

Spondylolisthesis is defined as the displacement or misalignment of the vertebral bodies one on top of the other. It comes from the Greek spondlylos, which means vertebra, and olisthesis, which means sliding on a slope. The nomenclature used to refer to spondylolisthesis consists of the following elements: vertebral segment (vertebrae involved), degree of sliding of one vertebral body over the other, the position of the upper vertebral body with respect to the lower one (anterolisthesis/retrolisthesis), and finally the etiology [1].

Surgical treatment of spondylolisthesis by oblique lumbar interbody fusion and transpedicular screw fixation: Comparison between conventional double position versus navigation-assisted single lateral position

BACKGROUND AND OBJECTIVES

Oblique lumbar interbody fusion (OLIF) procedures involve anterior insertion of interbody cage in lateral position. Following OLIF, insertion of pedicle screws and rod system is performed in a prone position (OLIF-con). The location of the cage is important for restoration of lumbar lordosis and indirect decompression. However, inserting the cage at the desired location is difficult without reduction of spondylolisthesis, and reduction after insertion of interbody cage may limit the amount of reduction. Recent introduction of spinal navigation enabled both surgical procedures in one lateral position (OLIF-one). Therefore, reduction of spondylolisthesis can be performed prior to insertion of interbody cage. The objective of this study was to compare the reduction of spondylolisthesis and the placement of cage between OLIF-one and OLIF-con.

METHODS

We retrospectively reviewed 72 consecutive patients with spondylolisthesis for this study; 30 patients underwent OLIF-one and 42 underwent OLIF-con. Spinal navigation system was used for OLIF-one. In OLIF-one, the interbody cage was inserted after reducing spondylolisthesis, whereas in OLIF-con, the cage was inserted before reduction. The following parameters were measured on X-rays: pre- and postoperative spondylolisthesis slippage, reduction degree, and the location of the cage in the disc space.

RESULTS

Both groups showed significant improvement in back and leg pains (p < .05). Transient motor or sensory changes occurred in three patients after OLIF-con and in two patients after OLIF-one. Pre- and postoperative slips were 26.3±7.7% and 6.6±6.2% in OLIF-one, and 23.1±7.0% and 7.4±5.8% in OLIF-con. The reduction of slippage was 74.4±6.3% after OLIF-one and 65.4±5.7% after OLIF-con, with a significant difference between the two groups (p = .04). The cage was located at 34.2±8.9% after OLIF-one and at 42.8±10.3% after OLIF-con, with a significant difference between the two groups (p = .004).

CONCLUSION

Switching the sequence of surgical procedures with OLIF-one facilitated both the reduction of spondylolisthesis and the placement of the cage at the desired location.

Diagnosis and Management of Spondylolysis and Spondylolisthesis in Children

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Spondylolysis is defined as a defect of the pars interarticularis, and spondylolisthesis is defined as a slippage of a vertebra relative to the immediately caudal vertebra.

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Most cases of spondylolysis and low-grade spondylolisthesis can be treated nonoperatively. Depending on a patient's age, nonoperative treatment may include a thoracolumbosacral orthosis (TLSO), physical therapy, and activity modification. Bracing and physical therapy have been found to be more effective than activity modification alone.

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Patients with dysplastic spondylolisthesis are at higher risk for progression and should be monitored with serial radiographs every 6 to 9 months.

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Operative management is recommended for symptomatic patients with failure of at least 6 months of nonoperative management or patients with high-grade spondylolisthesis.

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Surgical techniques include pars defect repair, reduction, and fusion, which may include posterior-only, anterior-only, or circumferential fusion.

Understanding the Pathophysiology of L5-S1 Loss of Lordosis and Retrolisthesis: An EOS Study of Lumbopelvic Movement Between Standing and Slump Sitting Postures

OBJECTIVE

To understand the pathophysiology of L5-S1 loss of lordosis and retrolisthesis by comparing 2 commonly assumed physiological weight-bearing postures.

METHODS

This was a prospective comparative study of whole-body standing and slump sitting EOS radiographs in clinic patients presenting with back pain or lower limb radicular pain. Patients with prior spinal intervention, malignancy, trauma, inflammatory diseases, transitional lumbosacral vertebra, pregnancy, and L5-S1 retrolisthesis or spondylolisthesis from nondegenerative causes were excluded. C7 sagittal vertical axis, global cervical angle, global thoracic angle, global lumbar angle, thoracolumbar angle, T1-slope, pelvic incidence, pelvic tilt, sacral slope, L5-S1 angle, L5-S1 vertebral translation, L5-S1 disc height, and presence of L4-5 vertebral translation were measured. Univariate and multivariate analyses were performed to identify predictors of L5-S1 lordosis loss and retrolisthesis.

RESULTS

L5-S1 loss of lumbar lordosis (7.02 ± 9.90°, P < 0.001), retrolisthesis (0.07 ± 0.411 cm, P < 0.001), and loss of disc height (0.10 ± 0.23 cm, P < 0.001) occurred when changing from standing to slump sitting along with other sagittal profile changes (P < 0.001). Taller L5-S1 disc height (odds ratio [OR] 2.57, P = 0.04), larger lumbar range-of-motion change (OR 3.82, P = 0.012), lower sacral slope on sitting (OR 2.50, P = 0.043), and presence of L4-5 spondylolisthesis (OR 2.75, P = 0.032) were predictive of larger L5-S1 lordosis loss (>7°) on multivariate analysis, while larger lumbar range-of-motion change (OR 2.21, P = 0.050) and presence of L4-5 spondylolisthesis (OR 3.08, P = 0.023) were predictive of greater L5-S1 retrolisthesis (>0.07 cm).

CONCLUSIONS

Degenerative L5-S1 loss of lordosis and retrolisthesis likely result from long-standing lower lumbar spine bending forces against the posterior ligamentous complex with slump sitting, predisposed by a negatively sloped sacrum and increased lumbar flexibility.

Clinical appearance and reliability in visual assessment after in situ fusion for high-grade isthmic spondylolisthesis

PURPOSE

The current literature on clinical appearance after surgery for high-grade spondylolisthesis is inconclusive. The few long-term comparative studies on surgical reduction versus in situ fusion report contradictory findings concerning appearance-related issues. The purpose of the current study was to evaluate and quantify clinical appearance three decades after in situ fusion for high-grade isthmic spondylolisthesis.

METHODS

The Scoliosis Research Society (SRS)-22r questionnaire, digital photographs and standing lateral radiographs were used to evaluate clinical appearance for 22 patients three decades after in situ fusion for high-grade spondylolisthesis. The appearance was assessed by two spine surgeons, by the patient themselves, and by quantification of cosmesis relevant radiographic variables including pelvic parameters and sagittal balance.

RESULTS

The surgeon inter- and intraobserver reliability of the photographic evaluation of the trunk deformity was at most moderate (Cohen's kappa 0.5). Correlation analysis revealed at most medium correlation between radiographic outcome and self-rated (SRS-22r) self-image (Spearman's rank correlation coefficient 0.3). The agreement between patient and surgeon-rated trunk appearance was poor (Cohen's kappa 0.2).

CONCLUSIONS

Photographic evaluation of the trunk deformity in high-grade spondylolisthesis is unreliable. There were only weak correlations between patient self-assessed trunk appearance and radiographic parameters. The results reflect the pronounced subjectivity of cosmesis, and that the trunk deformity in high-grade spondylolisthesis is not easily observed.

LEVEL OF EVIDENCE

IV.

Iliocava junction to L4-L5 disc anatomical relationship in L5-S1 isthmic spondylolisthesis

BACKGROUND

Anterior lumbar interbody fusion finds a place in L5-S1 isthmic spondylolisthesis (ISPL) treatment. Extension of this arthrodesis at L4-L5 level is sometimes required. Anterior approach of the L4L5 disc is considered difficult due to the anatomical relationship between the iliocava junction (ICJ) and the spine.

HYPOTHESIS

Does the lumbosacral deformation induced by ISPL allows anterior approach of L4-L5 disc between the iliac?

STUDY DESIGN

Retrospective radiographic analysis of consecutive patients.

METHODS

This retrospective imaging study of a continuous series of 97 patients treated for an L5-S1 ISPL involved radiological parameters specific to ISPL and pelvic-sagittal balance. The distance between the ICJ and the L4 lower endplate was measured in millimeters. The factors influencing this distance were sought in order to identify a predictive model of high ICJ.

RESULTS

The ICJ took a cranial position with respect to the L4-L5 disc with an average distance of 1.8mm±16.4. This distance was statistically higher in the case of high-grade ISPL (p<0.01). The high ICJ position was correlated with a high Taillard index (r=0.39; CI_95% [0.13; 0.61]; p<.001) and a low lumbar-sacral angle (LSA) (r=-0.33; CI_95% [-0.56; -0.06]; p<0.01). Among the parameters specific to spino-pelvic statics, pelvic incidence, pelvic tilt and lumbar lordosis had similar correlations (r>0.30).

CONCLUSION

ISPL induces a geometric deformation of the lumbosacral hinge which modifies its anatomical relations with the ICJ. The anterior approach technique of L4-L5 disc in the presence of an L5-S1 ISPL is possible between the iliac veins for the large displacement and low LSA forms.

LEVEL OF EVIDENCE

IV, retrospective analysis.

Comparison of lumbar segmental stabilization and general exercises on clinical and radiologic criteria in grade-I spondylolisthesis patients: A double-blind randomized controlled trial

OBJECTIVES

The effects of different physiotherapy protocols on patients suffering from grade-I spondylolisthesis have been thus far examined in a limited number of clinical trials. Therefore, the main purpose of this study was to compare the effects of lumbar segmental stabilization and general exercises on clinical and radiologic criteria in grade-I spondylolisthesis patients.

METHODS

This study was a double-blind randomized controlled trial (RCT) with a test-retest design and parallel groups. A total of 26 patients with grade-I spondylolisthesis were thus randomly assigned to experimental group (13 patients, lumbar segmental stabilization exercises) and control group (13 patients, general exercises). Subsequently, pain, functional disability, kinesiophobia, translational motion, angular motion and slip percentage of the vertebra were investigated.

RESULTS

Of the 120 people recruited in this study, only 26 patients were eligible. According to pre/post-intervention comparison, a statistically significant decrease was observed in the experimental group in terms of pain (p = 0.000), functional disability (p = 0.004), kinesiophobia (p = 0.002), translational motion (p = 0.043) and angular motion (p = 0.011), but not for slip percentage (p = 0.122). Considering the control group, a statistically significant decline was reported for pain (p = 0.043) and functional disability (p = 0.002). However, no significant differences were found for other variables in the control group. With regard to inter-group comparison, there was no statistically significant difference between the two groups regarding the given variables except for kinesiophobia (p = 0.040).

CONCLUSION

Both lumbar segmental stabilization and general exercises led to reduction in pain and functional disability of patients with grade-I spondylolisthesis. Therefore, lumbar segmental stabilization exercises seemed to be better than general ones with reference to improving kinesiophobia and intervertebral movements.

Sagittal Balance and Health-Related Quality of Life Three Decades After in Situ Arthrodesis for High-Grade Isthmic Spondylolisthesis

BACKGROUND

This case series of consecutive patients evaluated sagittal balance and health-related quality of life (HRQoL) 3 decades after in situ arthrodesis for high-grade isthmic spondylolisthesis.

METHODS

Global sagittal balance, pelvic parameters, and compensatory mechanisms were evaluated on standing lateral radiographs of the spine and pelvis for 28 of 39 consecutive patients, 28 to 41 years after in situ arthrodesis for high-grade L5 to S1 spondylolisthesis. The mean age at surgery was 14 years (range, 9 to 24 years), and the mean age at the time of follow-up was 48 years (range, 39 to 59 years). A subset of the radiographic parameters was compared with the corresponding data from an 8-year follow-up examination of the same patients. HRQoL was evaluated with the Scoliosis Research Society (SRS)-22r questionnaire.

RESULTS

We found that 3 of the 28 patients had a global sagittal imbalance (T1 spinopelvic inclination of >0°). Signs of compensatory mechanisms, such as reduced thoracic kyphosis and pelvic retroversion, were frequent. There was a significant decrease in sacral slope compared with 8-year follow-up data (p = 0.01). The median SRS-22r subscore was on the same level as Swedish normative data. We found no association between radiographic parameters and SRS-22r outcome.

CONCLUSIONS

Three decades after in situ arthrodesis for high-grade spondylolisthesis, radiographic signs of noncompensated sagittal imbalance were observed in only a few individuals. The patients had normal SRS-22r scores. There was no association between any radiographic parameter and SRS-22r outcome. The findings are relevant in the controversial discussion on whether to perform a reduction procedure to treat high-grade spondylolisthesis.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Degenerative Spondylolisthesis in the Fifth Lumbar Vertebra and Radiographic Parameters: A Correlation Analysis

STUDY DESIGN

A retrospective study.

OBJECTIVE

This study aimed to analyze the relationships between degenerative spondylolisthesis in the fifth lumbar vertebra (L5-DS) and radiographic parameters and to further determine the radiographic predictors of the development of L5-DS.

SUMMARY OF BACKGROUND DATA

Degenerative lumbar spondylolisthesis (DLS) is a common degenerative disease of the spine; however, the correlations between L5-DS and radiographic parameters remain controversial.

PATIENTS AND METHODS

This retrospective case-control study was conducted in our hospital. Between 2011 and 2014, a total of 84 subjects with L5-DS were enrolled in the DLS group, and 56 healthy volunteers were recruited to the control group. A series of radiographic parameters, including the bone mineral density, disk degenerative index, disk height, L5 vertebral size (L5-VS), lumbar lordosis angle (LL), sacral slope angle (SS), pelvic incidence (PI), facet joint angulations (FJA) of the cephalad and caudad portions, and asymmetry of the FJA, were measured in both groups by 3 examiners.

RESULTS

The bone mineral density, disk degenerative index, disk height, L5-VS, LL, SS, PI, and FJA exhibited significant differences (P=0.014-0.045) between the DLS and control groups. Significant changes in the FJA of the cephalad and caudad portions in the L4-L5 and L5-S1 segments were observed between the 2 groups (P=0.00, 0.00), whereas no significant differences in the asymmetries of FJA were observed in the L4-L5 or L5-S1 segments (P=0.605-0.972). Among all of the parameters, the L5-VS (P=0.025), SS (P=0.020), LL (P=0.031), PI (P=0.014), and FJA (P=0.022) were identified as being associated with the DLS group by multiple logistic regression analysis.

CONCLUSIONS

In this study, SS, LL, PI, and a more sagittal FJA were proven to be risk factors for L5-DS, whereas L5-VS was found to be a likely protective factor against L5-DS. These parameters should be considered predictors of L5-DS.

Lumbar degenerative spondylolisthesis epidemiology: A systematic review with a focus on gender-specific and age-specific prevalence

The epidemiology of lumbar degenerative spondylolisthesis (DS) remains controversial. We performed a systematic review with the aim of gaining a better understanding of the prevalence of DS in the general population. The results showed that the prevalence of DS is very gender- and age-specific. Few women and men develop DS before they are 50 years old. After 50 years of age, both women and men begin to develop DS, with women having a faster rate of development than men. For elderly Chinese (≥ 65 years, mean age: 72.5 years), large population-based studies MsOS (Hong Kong, females: n = 2000) and MrOS (Hong Kong, males: n = 2000) showed DS prevalence was 25.0% in women and 19.1% in men. The female:male (F:M) prevalence ratio was 1.3:1. The published data for MsOS (USA) and MrOS (USA) studies seem to show that elderly Caucasian Americans have a higher DS prevalence, being approximately 60-70% higher than elderly Chinese; however, the F:M prevalence ratio was similar to the elderly Chinese population. Patient data showed that female patients more often received surgical treatment than male and preliminary data showed the ratio of female to male patients receiving surgical treatment did not differ between Northeast Asians (Chinese, Japanese, and Korean), Europeans, and American Caucasians, being around 2:1 in the elderly population. The existing data also suggest that menopause may be a contributing factor for the accelerated development of DS in postmenopausal women. The translational potential of this article: A better understanding of epidemiology of lumbar degenerative spondylolisthesis can support patient consultation and treatment planning.

Roentgenologic Assessment of Spondylolisthesis

Different degrees of artificial L5-SI spondylolisthesis were created using a lumbar specimen. Lateral radiographs were obtained of each, with the specimen tilted and/or rotated. The true spondylolisthesis was determined stereophotogrammetrically. The slip, measured on the radiographs, was calculated according to two methods modified from Boxall et coll. (2). No significant difference in accuracy was found between these two methods. The difference in calculated slip between examinations needs to be at least 20 per cent of the sagittal length of L5 to be regarded as a true progression. A true progress of slip of less than 20 per cent is difficult to detect with statistical certainty.

Routine Upright Imaging for Evaluating Degenerative Lumbar Stenosis: Incidence of Degenerative Spondylolisthesis Missed on Supine MRI

STUDY DESIGN

A retrospective cohort.

BACKGROUND

Degenerative spondylolisthesis (DS) with lumbar stenosis is a well-studied pathology and diagnosis is most commonly determined by a combination of magnetic resonance imaging (MRI) and standing radiographs. However, routine upright imaging is not universally accepted as standard in all practices. To the best of our knowledge, there has been no study investigating the incidence of missed diagnosis of DS evident only on standing lateral or dynamic radiographs when compared with sagittal alignment on MRI.

OBJECTIVE

The authors hypothesize that supine MRI evaluation alone in lumbar degenerative disease will significantly underestimate the incidence of DS. Secondary hypothesis is that there will be no significant difference in detecting spondylolisthesis when comparing dynamic flexion-extension radiographs to standing lateral radiographs.

METHODS

We retrospectively evaluated all patients presenting to spine clinic for degenerative lumbar conditions from July 2004 to July 2006 who had an MRI, upright lateral, and flexion-extension radiographs at our institution. The incidence of DS found on dynamic flexion-extension radiographs but not on MRI was determined. We then reviewed each and compared flexion-extension versus standing lateral views to determine whether there was any significant difference in detecting anterolisthesis.

RESULTS

Of 416 patients with eligible studies, 109 were found to have DS at levels L4-L5, L5-S1, or L3-L4 based on flexion-extension radiographs. Of these, only 78 were found to have a corresponding spondylolisthesis on MRI, leaving 31/109 (28%) of DS levels undiagnosed on MRI. No additional anterolisthesis cases were detected on standing flexion-extension verses standing lateral radiographs.

CONCLUSIONS

Routine standing lateral radiographs should be standard practice to identify DS, as nearly 1/3 of cases will be missed on supine MRI. This may have implications on whether or not an arthrodesis is performed on those patients requiring lumbar decompression. Flexion-extension radiographs demonstrated no added value compared with standing lateral x-rays for the purposes of diagnosing DS.

Functional radiography in examination of spondylolisthesis

OBJECTIVE

Despite the predominant use of standing flexion-extension radiography for quantifying instability in isthmic and degenerative spondylolisthesis, other functional radio-graphic techniques have been presented in the literature.

CONCLUSION

The current evidence reported in the literature is insufficient to influence how the results of these other functional radiographic techniques should affect clinical management; however, it does raise doubts regarding the accuracy and reliability of standing flexion-extension radiography in this setting. Based on the currently available evidence and until randomized studies are performed to assess the efficacy of functional radiographic techniques in directing clinical decision making, positioning schemes other than traditional standing flexion-extension may be considered as options in the evaluation of patients with symptomatic isthmic and degenerative spondylolisthesis in which standard flexion-extension radiographs fail to show pathologic instability.

Retrolisthesis and lumbar disc herniation: a postoperative assessment of patient function

BACKGROUND CONTEXT

The presence of retrolisthesis has been associated with the degenerative changes of the lumbar spine. However, retrolisthesis in patients with L5-S1 disc herniation has not been shown to have a significant relationship with worse baseline pain or function. Whether it can affect the outcomes after discectomy, is yet to be established.

PURPOSE

The purpose of this study was to determine the relationship between retrolisthesis (alone or in combination with other degenerative conditions) and postoperative low back pain, physical function, and quality of life. This study was intended to be a follow-up to a previous investigation that looked at the preoperative assessment of patient function in those with retrolisthesis and lumbar disc herniation.

STUDY DESIGN

Cross-sectional study.

PATIENT SAMPLE

Patients enrolled in SPORT (Spine Patient Outcomes Research Trial) who had undergone L5-S1 discectomy and had a complete magnetic resonance imaging scan available for review (n=125). Individuals with anterolisthesis were excluded.

OUTCOME MEASURES

Time-weighted averages over 4 years for the Short Form (SF)-36 bodily pain scale, SF-36 physical function scale, Oswestry Disability Index (ODI), and Sciatica Bothersomeness Index (SBI).

METHODS

Retrolisthesis was defined as a posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 to 3 and collectively classified as vertebral end plate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy was classified jointly as posterior degenerative changes. Longitudinal regression models were used to compare the time-weighted outcomes over 4 years.

RESULTS

Patients with retrolisthesis did significantly worse with regard to bodily pain and physical function over 4 years. However, there were no significant differences in terms of ODI or SBI. Similarly, retrolisthesis was not a significant factor in the operative time, blood loss, lengths of stay, complications, rate of additional spine surgeries, or recurrent disc herniations. Disc degeneration, modic changes, and posterior degenerative changes did not affect the outcomes.

CONCLUSIONS

Although retrolisthesis in patients with L5-S1 disc herniation did not affect the baseline pain or function, postoperative outcomes appeared to be somewhat worse. It is possible that the contribution of pain or dysfunction related to retrolisthesis became more evident after removal of the disc herniation.

Biomechanics of intervertebral disk degeneration

Degenerative changes in the material properties of nucleus pulposus and anulus fibrosus promote changes in viscoelastic properties of the whole disc. Volume, pressure and hydration loss in the nucleus pulposus, disk height decreases and fissures in the anulus fibrosus, are some of the signs of the degenerative cascade that advances with age and affect, among others, spinal function and its stability. Much remains to be learned about how these changes affect the function of the motion segment and relate to symptoms such as low back pain and altered spinal biomechanics.

Clinical tests to diagnose lumbar segmental instability: a systematic review

STUDY DESIGN

Systematic literature review.

OBJECTIVES

To evaluate the diagnostic accuracy of clinical tests used to diagnose patients with structural lumbar segmental instability (LSI).

BACKGROUND

Patients with structural LSI represent an important, identifiable subgrouping of individuals with low back pain. Numerous clinical tests have been proposed to diagnose structural LSI; however, data on the diagnostic accuracy of these tests have not yet been evaluated through a systematic review of the literature.

METHODS

A systematic review was conducted in 6 electronic databases for diagnostic accuracy studies, published between January 1950 and March 2010, that evaluated clinical tests against radiological diagnosis of structural LSI. The diagnostic accuracy of the clinical tests from the retrieved articles was independently evaluated, reviewed, and quality scored using the QUADAS tool.

RESULTS

Four articles and a total of 11 clinical tests used in the diagnosis of structural LSI met the study inclusion criteria. The majority of tests had high specificity but low sensitivity, with positive likelihood ratios ranging from very small to moderate. QUADAS scores ranged from 16 to 25 out of a possible 26. The passive lumbar extension test was the most accurate clinical test, with high sensitivity (84%), specificity (90%), and a positive likelihood ratio of 8.8 (95% CI: 4.5, 17.3), indicating that this clinical test may be useful in the differential diagnosis of structural LSI.

CONCLUSION

This systematic review found that the majority of clinical tests routinely employed to diagnose structural LSI demonstrated only limited ability to do so. The results do, however, indicate that the passive lumbar extension test may be useful in orthopaedic clinical practice to diagnose structural LSI. Additional research is required to further validate its use for diagnosing structural LSI in all populations of those with low back pain.

LEVEL OF EVIDENCE

Diagnosis, level 2a.

Redefining the technique for the radiologic measurement of slip in spondylolisthesis

STUDY DESIGN

Comparison of 2 radiographic measurement techniques of slip severity in spondylolisthesis.

OBJECTIVE

To analyze the differences between 2 radiologic measurement techniques of slip severity in L5-S1 developmental spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Different techniques for the assessment of slip in spondylolisthesis have been described in the literature, resulting in 2 different methods to report the position of the L5 vertebra on the S1 superior endplate. The clinical impact of these differences in slip measurement is unknown.

METHODS

Radiographs of 130 subjects with developmental spondylolisthesis were reviewed. Two different techniques were used to assess the grade and percentage of slip. The technique 1 uses a line drawn from the L5 vertebra postero-inferior corner that is perpendicular to the S1 vertebra endplate. The technique 2 uses a line tangential to the L5 vertebra posterior wall that intersects the S1 vertebra endplate. The lumbosacral angle (LSA) was also measured to assess the orientation of L5 over S1. The slip percentage and grade obtained from the 2 techniques were compared. The influence of the LSA on the measurement of slip severity was also assessed.

RESULTS

A significant difference (P < 10(-5)) was found between technique 1 (mean = 34.2% +/- 32.6%) and technique 2 (mean = 42.5% +/- 25.8%) with respect to the slip percentage. Eight subjects were found to switch classification from a low to a high-grade slip (or inversely) depending on the technique used. There was a significant relationship between the LSA and the difference in the measurement of slip percentage using either technique 1 or technique 2.

CONCLUSION

The 2 measurement techniques can have a significant impact on the interpretation of slip severity in spondylolisthesis. The differences between the measurement techniques are influenced by the orientation of L5 over S1 and could potentially affect the clinical decision making. It is important to standardize and specify the technique used to plan and assess interventions in L5-S1 developmental spondylolisthesis.

Spondylolisthesis: intraobserver and interobserver reliability with regard to the measurement of slip percentage

BACKGROUND

Spondylolisthesis is often diagnosed and treated on the basis of measurements obtained from radiographs. Many physicians will perform surgery regardless of the patient's symptoms above a specific slip percentage. However, current methods used to assess slip percentage are vague and lack appropriate standardization, leaving physicians to devise personal evaluation techniques. This study presents a defined method to calculate slip percentage that takes advantage of modern technology, is fast and simple to perform, and shows excellent intraobserver/interobserver reliability.

METHODS

Four pediatric orthopaedic attendings each reviewed 30 radiographic cases of spondylolisthesis (grades 1 to 4) at the L5 to S1 level. The radiographs were measured twice through computer using PACS information management software with an interval of 2 days to 2 weeks between sessions. Using the PACS line tool, observers superimposed 6 lines onto each radiograph from which measurements were derived. The numerator in slip percentage (anterior displacement) was determined by 2 methods: the distance between a line outlining the posterior border of the sacrum and A: a line outlining the posterior border of L5 or B: a line parallel starting at the inferior, posterior corner of L5. The denominator in slip percent was determined by 2 methods. C: length of the inferior border L5 or D: length of the superior border of L5. This resulted in 4 different equations of slip percentage: A/C, A/D, B/C, and B/D. Analysis was performed using intraclass correlation coefficient.

RESULTS

Slip percentage=A/D resulted in the highest intraclass correlation coefficient for both intraobserver and interobserver reliability (0.87 and 0.85, respectively). Slip percentage=B/C showed the poorest intraobserver reliability (0.69). Slip percentage=B/C and B/D had equally poor interobserver reliability (0.59).

CONCLUSIONS

Defining the numerator in slip percentage as the distance between a line outlining the posterior border of the sacrum and a line outlining the posterior border of L5 (A) results in the highest intraobserver/interobserver reliability. Defining the denominator in slip percentage as the length of the superior border of L5 (D) results in the highest intra/inter observer reliability.

LEVEL OF EVIDENCE

Diagnostic level III.

Kinematic analysis of dynamic lumbar motion in patients with lumbar segmental instability using digital videofluoroscopy

The study design is a prospective, case-control. The aim of this study was to develop a reliable measurement technique for the assessment of lumbar spine kinematics using digital video fluoroscopy in a group of patients with low back pain (LBP) and a control group. Lumbar segmental instability (LSI) is one subgroup of nonspecific LBP the diagnosis of which has not been clarified. The diagnosis of LSI has traditionally relied on the use of lateral functional (flexion-extension) radiographs but use of this method has proven unsatisfactory.Fifteen patients with chronic low back pain suspected to have LSI and 15 matched healthy subjects were recruited. Pulsed digital videofluoroscopy was used to investigate kinematics of lumbar motion segments during flexion and extension movements in vivo. Intersegmental linear translation and angular displacement, and pathway of instantaneous center of rotation (PICR) were calculated for each lumbar motion segment. Movement pattern of lumbar spine between two groups and during the full sagittal plane range of motion were analyzed using ANOVA with repeated measures design. Intersegmental linear translation was significantly higher in patients during both flexion and extension movements at L5-S1 segment (p < 0.05). Arc length of PICR was significantly higher in patients for L1-L2 and L5-S1 motion segments during extension movement (p < 0.05). This study determined some kinematic differences between two groups during the full range of lumbar spine. Devices, such as digital videofluoroscopy can assist in identifying better criteria for diagnosis of LSI in otherwise nonspecific low back pain patients in hope of providing more specific treatment.

Diagnosis and conservative management of degenerative lumbar spondylolisthesis

Degenerative spondylolisthesis (DS) is a disorder that causes the slip of one vertebral body over the one below due to degenerative changes in the spine. Lumbar DS is a major cause of spinal canal stenosis and is often related to low back and leg pain. We reviewed the symptoms, prognosis and conservative treatments for symptoms associated with DS. PubMed and MEDLINE databases (1950-2007) were searched for the key words "spondylolisthesis", "pseudospondylolisthesis", "degenerative spondylolisthesis", "spinal stenosis", "lumbar spine", "antherolisthesis", "posterolisthesis", "low back pain", and "lumbar instability". All relevant articles in English were reviewed. Pertinent secondary references were also retrieved. The prognosis of patients with DS is favorable, however, those who suffer from neurological symptoms such as intermittent claudication or vesicorectal disorder, will most probably experience neurological deterioration if they are not operated upon. Nonoperative treatment should be the initial course of action in most cases of DS, with or without neurologic symptoms. Treatment options include use of analgesics and NSAIDs to control pain; epidural steroid injections, and physical methods such as bracing and flexion strengthening exercises. An up-to-date knowledge on diagnosis and prevention of lumbar DS can assist in determination of future research goals. Additional studies are required to establish treatment protocols for the conservative treatment of DS.

Lumbar intervertebral instability: a review

Intervertebral instability of the lumbar spine is thought to be a possible pathomechanical mechanism underlying low back pain and sciatica and is often an important factor in determining surgical indication for spinal fusion and decompression. Instability of the lumbar spine, however, remains a controversial and poorly understood topic. At present, much controversy exists regarding the proper definition of the condition, the best diagnostic methods, and the most efficacious treatment approaches. Clinical presentation is not specific, and the relationship between radiologic evidence of instability and its symptoms is controversial. Because of its simplicity, low expense, and pervasive availability, functional flexion-extension radiography is the most thoroughly studied and the most widely used method in the imaging diagnosis of lumbar intervertebral instability. In this article, we provide an overview of the current concepts of vertebral instability, focusing on degenerative lumbar intervertebral instability, and review the different imaging modalities most indicated in diagnosing vertebral instability.

Fluoroscopic video to identify aberrant lumbar motion

STUDY DESIGN

A prospective, case-control design.

OBJECTIVES

To develop a kinematic model that characterizes frequently observed movement patterns in patients with low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Understanding arthrokinematics of lumbar motion in those with LBP may provide further understanding of this condition.

METHODS

Digital fluoroscopic video (DFV) was used to quantify the magnitude and rate of attainment of sagittal plane intersegmental angular and linear displacement from 20 individuals with LBP and 20 healthy control subjects during lumbar flexion and extension. Three fellowship-trained spine surgeons subsequently qualitatively analyzed the DFVs to determine normality of movement. Final classification was based on agreement between their symptom and motion status (11 with LBP and aberrant motion and 14 healthy controls without aberrant motion). Independent t tests, receiver operator characteristic curves, and accuracy statistics were calculated to determine the most parsimonious set of kinematic variables able to distinguish patients with LBP.

RESULTS

Eight kinematic variables had a positive likelihood ratio > or = 2.5 and entered the model. Six of the variables described a disruption in the rate of attainment of angular or linear displacement during midrange postures. When 4 or more of these variables were present, the positive likelihood ratio was 14.0 (confidence interval 3.2-78.5), resulting in accurately identifying 96% of participants.

CONCLUSIONS

DFV was useful for discriminating between individuals with and without LBP based on kinematic parameters. Disruptions in how the motion occurred during midrange motions were more diagnostic for LBP than range of motion variables. Cross validation of the model is required.

Arthrokinematics in a subgroup of patients likely to benefit from a lumbar stabilization exercise program

BACKGROUND AND PURPOSE

A clinical prediction rule (CPR) has been reported to identify patients with low back pain who are likely to benefit from stabilization exercises. The aim of this study was to characterize the spinal motion, using digital fluoroscopic video, of a subgroup of subjects with low back pain.

SUBJECTS

Twenty subjects who were positive on the CPR were compared with 20 control subjects who were healthy.

METHODS

The magnitude and timing of lumbar sagittal-plane intersegmental angular and linear displacement were assessed. Receiver operating characteristic curves and accuracy statistics were used to develop a kinematic model.

RESULTS

A 10-variable model was developed that could distinguish group membership. Seven of these variables described a disruption in timing of angular or linear displacement during mid-range movements. None of the variables suggested hypermobility.

DISCUSSION AND CONCLUSION

The findings suggest that individuals with mid-range aberrant motion without signs of hypermobility are likely to benefit from these exercises. The developed model describes altered kinematics of this subgroup of subjects and helps to provide construct validity for the developed CPR.

A new technique for digital fluoroscopic video assessment of sagittal plane lumbar spine motion

STUDY DESIGN

Methodological reliability.

OBJECTIVE

Develop a measurement technique to assess dynamic motion of the lumbar spine using enhanced digital fluoroscopic video (DFV) and a distortion compensated roentgen analysis (DCRA).

SUMMARY OF BACKGROUND DATA

Controversy over both the definition and consequences of lumbar segmental instability persists. Information from static imaging has had limited success in providing an understanding of this disorder. DFV has the potential to provide further information about lumbar segmental instability; however, the image quality is poor and clinical application is limited.

METHODS

DFV from 20 male subjects (11 with and nine without low back pain) were obtained during eccentric lumbar flexion (30 Hz). Each DFVs was enhanced with a series of filters to accentuate the vertebral edges. An adapted DCRA algorithm was applied to determine segmental angular and linear displacement. Both intraimage and interimage reliability were assessed using intraclass correlation coefficients (ICC) and standard error of the measurement (SEM). RESULTS.: Intraimage reliability yielded an average ICC of 0.986, and the SEM ranged from 0.4-0.7 degrees and 0.2-0.3 mm. Interimage reliability yielded an average ICC of 0.878, and the SEM ranged from 0.7-1.4 degrees and 0.4-0.7 mm.

CONCLUSIONS

Enhanced DFV combined with a DCRA resulted in reliable assessment of lumbar spine kinematics. The error values associated with this technique were low and were comparable to published error measurements obtained when using a similar algorithm on hand-drawn outlines from static radiographs.

“Supine-Prone” Dynamic X-Ray Examination

Lumbar instability often causes clinical symptoms, and spondylolisthesis is a main factor of the low back pain. Segmental lumbar instability generally is due to a degenerative or listhesic process of the lumbar spine and radiological imaging is essential to diagnose it. Lumbar spine segmental mobility has commonly been studied by dyanamic radiographic methods. Dynamic X-rays, with maximal extension and flexion of the lumbar tract, represents the most widely used technique and a valid method to estimate sagittal segmental lumbar motion. Between 1998 and 2002 we treated 75 patients for low-grade spondylolisthesis. All patients underwent a preoperative dynamic X-rays examinination, to evaluate the degree of the lumbar mobility. We report a supine-prone position as new method to clearly estimate the slipping of lumbar vertebrae. The patients had a standard lateral X-rays film in the supine position, and then in the "prone" position. We compared the two methods and we found a higher degree of listhesis in 19 cases (14 I grade, 5 I-II grade), while there was no difference in 56 cases. The higher degree of listhesis was in the prone position. We believe that the supine-prone position is an economic method and should be mandatory performing a dynamic X-rays examination.

Intervertebral mobility in the progressive degenerative process. A radiostereometric analysis

Three separate stages have previously been defined in the progressive degenerative process. The first stage, characterized as temporary dysfunction with early degenerative findings, transforms into a second period of segmental instability evidenced by a resulting deformity. With the deformity the process has reached a late stage of definitive stabilization induced by osteoligamentary repair mechanisms. To test the validity of this three-stage hypothesis, we assessed the intervertebral mobility for the two most-distal lumbar disc levels in 18 adult patients with low back pain, disc degenerative findings and no prior spinal surgery. Each spinal segment was categorized according to grade of disc degeneration: (IA) normal disc height without dehydration; (IB) normal disc height with dehydration; (II) disc height decreased by less than 50%; (III) disc height decreased by at least 50%; and (IV) disc height obliterated. The intervertebral mobility was measured by radiostereometric analysis (RSA) and compared between the categories. With the patient changing position from supine to sitting, the mean vertical translation across the 11 discs categorized as IA was 2.0 mm. A small increase in mean vertical mobility with progressive loss of disc height through the degenerative stages IB (2.2 mm, seven discs) and II (2.6 mm, ten discs) was not significant. Further degeneration to grade III meant a significant mean reduction in vertical mobility to 0.8 mm for the eight discs in that category. No discs were classified as obliterated, category IV. The corresponding values for sagittal translations were 3.0 mm, 3.1 mm, 3.6 mm and 1.7 mm for the four disc categories found. These alterations were not statistically significant. We conclude that intervertebral mobility changes throughout the degenerative process, and a stage of stabilization begins when disc height is reduced by 50%. The segmental mobility status cannot be deduced from the radiographic, degenerative disc stage, since the inter-individual differences in mobility are pronounced for the same disc status. A fully stable situation cannot be taken for granted, even when the disc is reduced by more than 50%, considering the fact that some persisting mobility was seen for most patients in category III. A preceding stage of instability, in the clinical situation proven by a resulting deformity, was not verified in this study.

Radiologic findings and curve progression 22 years after treatment for adolescent idiopathic scoliosis: comparison of brace and surgical treatment with matching control group of straight individuals

STUDY DESIGN

This study is a follow-up investigation for a consecutive series of patients with adolescent idiopathic scoliosis treated between 1968 and 1977. In this series, 156 patients underwent surgery with distraction and fusion using Harrington rods, and 127 were treated with brace.

OBJECTIVES

To determine the long-term outcome in terms of radiologic findings and curve progression at least 20 years after completion of the treatment.

SUMMARY OF BACKGROUND DATA

Radiologic appearance is important in comparing the outcome of different treatment options and in evaluating clinical results. Earlier studies have shown a slight increase of the Cobb angle in brace-treated patients with time, but not in fused patients.

METHODS

Of 283 patients, 252 attended a clinical and radiologic follow-up assessment by an unbiased observer (91% of the surgically treated and 87% of the brace-treated patients). This evaluation included chart reviews, validated questionnaires, clinical examination, and full-length standing frontal and lateral roentgenographs. Curve size was measured by the Cobb method on anteroposterior roentgenograms as well as by sagittal contour and balance on lateral films. The occurrence of any degenerative changes or other complications was noted. An age- and gender-matched control group of 100 individuals was randomly selected and subjected to the same examinations.

RESULTS

The mean follow-up times were 23 years for surgically treated group and 22 years for brace-treated group. The deterioration of the curves was 3.5 degrees for all the surgically treated curves and 7.9 degrees for all the brace-treated curves (P < 0.001). Five patients, all brace-treated, had a curve increase of 20 degrees or more. The overall complication rate after surgery was low: Pseudarthrosis occurred in three patients, and flat back syndrome developed in four patients. Eight of the patients treated with fusion (5.1%) had undergone some additional curve-related surgical procedure. The lumbar lordosis was less in the surgically treated than in the brace-treated patients or the control group (mean, 33 degrees vs 45 degrees and 44 degrees, respectively). Both surgically treated and brace-treated patients had more degenerative disc changes than the control participants (P < 0.001), but no significant differences were found between the scoliosis groups. No statistically significant difference in terms of radiographically detectable degenerative changes in the unfused lumbar discs was found between patients fused below L3 or those fused to L3 and above (P = 0.22). A study on intra- and interobserver measurements of kyphosis, lordosis, and sagittal vertical axis on two films for each patient demonstrated that the repeatability of measuring sagittal plumbline on two different lateral radiographs, with patients moving between radiograms, was unreliable for comparison.

CONCLUSIONS

Although more than 20 years had passed since completion of the treatment, most of the curves did not increase. The surgical complication rate was low. Degenerative disc changes were more common in both patient groups than in the control group.

Is there increased intervertebral mobility in isthmic adult spondylolisthesis? A matched comparative study using roentgen stereophotogrammetry

STUDY DESIGN

By roentgen stereophotogrammetric technique, the intervertebral mobility of the spondylolytic segment in eight patients was measured and compared with the mobility of eight nonspondylolytic patients matched according to sex, afflicted segment, and grade of disc degeneration.

OBJECTIVES

To compare the intervertebral mobility of a spondylolytic segment with the mobility of a segment without spondylolysis in adult patients with back pain.

SUMMARY OF BACKGROUND DATA

Evidenced by the resulting olisthetic deformity and supported by the outcome from prior investigations, spondylolysis is assumed to induce spinal segmental instability/hypermobility.

METHODS

After percutaneous application of tantalum indicators for roentgen stereophotogrammetric technique, the intervertebral translations of the spondylolytic fifth lumbar vertebra were measured in eight adult patients with low back pain and low-grade olisthesis. Eight other patients without spondylolysis but with low back pain presumably on degenerative basis were chosen for comparison and had an identical measuring procedure using roentgen stereophotogrammetric technique. The two groups were matched in pairs according to sex, afflicted segment, and grade of disc degeneration.

RESULTS

No significant difference was registered considering the intervertebral mobility for matched pairs in the two groups neither along the sagittal nor the vertical axis. The transverse translations were mostly negligible in both groups.

CONCLUSION

The spondylolytic defect in pars interarticularis does not cause permanent instability/hypermobility detectable in the adult patient with low back pain and low-grade olisthesis.

Lumbar olisthesis and lower back symptoms in elderly white women. The Study of Osteoporotic Fractures

STUDY DESIGN

A Cross-sectional study.

OBJECTIVES

To determine the prevalence of lumbar olisthesis among white women aged 65 years and older and its relation to low back pain and back function.

BACKGROUND

Degenerative changes in the lumbar spine of elderly individuals may affect spinal stability, causing olisthesis (subluxation) of the lumbar spine. Neither the prevalence of this condition in the United States nor its relation to back symptoms has been studied previously.

METHODS

Lateral radiographs of the lumbar spine for 788 women aged 65 years and older who were enrolled in the Study of Osteoporotic Fractures were digitized. Olisthesis (antero- and retro-) was assessed at L3-L4, L4-L5, and L5-S1. Back pain and function also were assessed.

RESULTS

When olisthesis was defined as subluxation of 3 mm or more at any of the three levels studied, the overall prevalence of anterolisthesis was 29% and that of retrolisthesis was 14%. In 90% of women with anterolisthesis and 88% of women with retrolisthesis, subluxation occurred at a single vertebral level. The prevalence of anterolisthesis and retrolisthesis did not vary by smoking status, presence of diabetes, or history of oophorectomy. Anterolisthesis was not associated with the presence of back symptoms. Only retrolisthesis at L3-L4 was associated with a statistically significantly increased likelihood of lower back pain, greater severity of back pain, and impairment of back function.

CONCLUSIONS

Anterolisthesis of 3 mm or more in the lower lumbar spine is relatively common among elderly women but is not correlated with back problems. Retrolisthesis at L3-L4 is associated with increased back pain and impaired back function.

Assessment of sagittal plane segmental motion in the lumbar spine. A comparison between distortion-compensated and stereophotogrammetric roentgen analysis

STUDY DESIGN

Sagittal plane translatory and rotatory motion was measured in 15 lumbar motion segments of 8 patients by distortion-compensated and stereophotogrammetric Roentgen analysis.

OBJECTIVE

To compare measurement precision of the new distortion-compensated Roentgen analysis protocol with that of the established Roentgen stereophotogrammetric technique under realistic clinical conditions.

SUMMARY OF BACKGROUND DATA

Roentgen stereophotogrammetric analysis constitutes the most precise method available to assess segmental motion. Because of the invasive nature of the procedure, however, there is interest in alternative, noninvasive protocols suitable for studying larger patient cohorts.

METHODS

In 8 patients, segmental motion of 15 lumbar segments that had undergone previous spinal surgery was assessed from stereo views by using Roentgen stereophotogrammetric analysis. Sagittal plane segmental motion was assessed by distortion-compensated Roentgen analysis. Sagittal plane translatory and rotatory motion data obtained by both methods were compared.

RESULTS

With respect to Roentgen stereophotogrammetric analysis, sagittal plane rotation was determined by distortion-compensated Roentgen analysis with an error (standard deviation) of 1.4 degrees and a mean difference of less than 0.05 degree. Sagittal plane translation was determined by distortion-compensated Roentgen analysis, with an error of 1.25 mm and a mean difference 0.5 mm.

CONCLUSION

Measurement precision of distortion-compensated Roentgen analysis is slightly inferior to that of Roentgen stereophotogrammetric analysis but substantially higher than that of conventional protocols assessing lumbar segmental motion. If measurement precision is considered adequate and if a noninvasive technique is indicated, distortion-compensated Roentgen analysis can be used to provide reliable motion data required for epidemiologic and clinical studies.

Posterolateral lumbar fusion. Outcome of 71 consecutive operations after 4 (2-7) years

We report the outcome of 71 consecutive posterolateral lumbar fusions without spinal instrumentation. The indication for the operation was spondylolysis-olisthesis, degenerative disc disease/facet joint arthrosis, or pain after prior laminectomy. Concerning pain relief, 29/43 patients with spondylolysis-olisthesis were classified as good. The corresponding figures in the group with degenerative disc disease and/or facet joint arthrosis were 8/16 patients and in the group with pain post-laminectomy, 6/12 patients. No surgical complications were noted. In the total material 54 patients had a solid fusion, as defined by radiographic osseous trabecular bridging at all intended levels. One-level fusions tended to heal solidly in a higher frequency than two-level fusions. For the spondylolysis-olisthesis group, healed fusion correlated with a good clinical result. Such a correlation could not be verified for the other diagnostic groups. We conclude that non-instrumented posterolateral lumbar fusion is a valid method for treating low-grade spondylolysis-olisthesis, especially when the aim is to fuse a single level. Improved patient selection methods are required in fusion for degenerative disc disease and pain after laminectomy.

Specific pattern of ruptured annulus fibrosus in lumbar degenerative spondylolisthesis

In order to study the antepriori etiologic factors of degenerative spondylolisthesis, the discograms and CTD were analyzed and the rate of disc slipping and disc indices wer evaluated in 30 cases with degenerative spondylolisthesis. (1) The characteristic S-shaped image which extended from anteroinferior to posterosuperior up to the posterior margin of a vertebral body was observed in 89.7% of slipped discs in lateral discograms. CTD revealed that this image represented a circular splitting in the external and intermediate annulus fibrosus. (2) Discographic degeneration of the discs adjacent to a slipped disc was relatively mild, and their disc indices were not significantly different from those of controls. (3) A negative correlation with r = -0.434 was found between the slipping rate and the disc index. From these results, it was postulated that the site and direction of the circular splitting in laminae of the annulus fibrosus, and the direction of the load applied to an intervertebral disc are important etiologic factors of degenerative spondylolisthesis.