Comparative study of lumbopelvic sagittal alignment between patients with and without sacroiliac joint pain after lumbar interbody fusion

The Effect of Changes in Segmental Lordosis on Global Lumbar and Adjacent Segment Lordosis After L5-S1 Anterior Lumbar Interbody Fusion

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

Restoration of lordosis in lumbar fusion reduces low back pain, decreases adjacent segment degeneration, and improves postoperative outcomes. However, the potential effects of changes in segmental lordosis on adjacent-level and global lordosis remain less understood. This study aims to examine the relationships between segmental (SL), adjacent-level, and global lumbar lordosis following L5-S1 Anterior Lumbar Interbody Fusion (ALIF).

METHODS

80 consecutive patients who underwent single-level L5-S1 ALIF were divided into 3 groups based on the degree of change (∆) in index-level segmental lordosis: <5° (n = 23), 5°-10° (n = 29), >10° (n = 28). Radiographic parameters measured included global lumbar, segmental, and adjacent level lordosis, sacral slope, pelvic tilt, pelvic incidence, and PI-LL mismatch.

RESULTS

Patients with ∆SL 5°-10° or ∆SL >10° both showed significant increases in global lumbar lordosis from preoperative to final follow-up. However, patients with ∆SL >10° showed statistically significant losses in adjacent level lordosis at both immediate postoperative and final follow-up compared to preoperative. When comparing patients with ∆SL >10° to those with ∆SL 5-10°, there were no significant differences in global lumbar lordosis at final follow-up, due to significantly greater losses of adjacent level lordosis in these patients.

CONCLUSION

The degree of compensatory loss of lordosis at the adjacent level L4-L5 correlated with the extent of segmental lordosis creation at the index L5-S1 level. This may suggest that the L4 to S1 segment acts as a "harmonious unit," able to accommodate only a certain amount of lordosis and further increases in segmental lordosis may be mitigated by loss of adjacent-level lordosis.

Sacroiliac Joint Degeneration After Lumbar or Lumbosacral Fusion Surgery-A Comparative Study of the Number of Fused Segments and Sacral Fusion

OBJECTIVE

In this study, we aimed to investigate whether multi-segment fusion or fusion-to-sacrum increases sacroiliac joint (SIJ) pathology compared with single-segment fusion or a non-fused sacrum.

METHODS

This study included 116 patients who underwent lumbar or lumbosacral fusion and were followed up for 2 years. The patients were classified into single-segment fusion (n = 46) and multi-segment fusion (more than two levels, n = 70) groups and then reclassified into the non-fused sacrum (n = 68) and fusion-to-sacrum groups (n = 48). Preoperative and postoperative radiographs were used to evaluate radiographic parameters, and computed tomography (CT) was used to evaluate SIJ degeneration. Low back pain (LBP) was assessed using a visual analog scale (VAS, 0-10). Baseline and postoperative values were compared using a paired sample t-test.

RESULTS

LBP VAS scores significantly differed at 6 months (single-segment fusion, 3.04±1.88; multi-segment fusion, 4.83±2.33; P < 0.001) and 2 years postoperatively (single-segment fusion, 3.3±2.2; multi-segment fusion, 4.78±2.59; P = 0.094). There was no significant difference in SIJ degeneration, as assessed by CT scan, between the 2 surgical groups: 14 (30%) and 19 (27%) patients in the single-segment and multi-segment (P = 0.701) fusion groups, respectively. The LBP VAS scale showed comparable differences at 1 (non-fused sacrum, 3±2.18; fusion-to-sacrum, 3.74±2.28; P = 0.090) and 2 years postoperatively (non-fused sacrum, 3.29±2.01; fusion-to-sacrum, 4.66±2.71; P = 0.095). CT scan revealed that 18 (26%) and 15 (31%) patients in the non-fused sacrum and fusion-to-sacrum groups, respectively, developed SIJ arthritis; however, there was no significant intergroup difference (P = 0.574).

CONCLUSIONS

SIJ degeneration occurs independent of the number of fused segments or sacrum involvement.

Incidence and risk factors of new-onset sacroiliac joint pain after spinal surgery: a systematic review and meta-analysis

Purpose

A systematic review and meta-analysis for incidence and risk factors of new-onset sacroiliac joint pain (SIJP) after spinal surgery aimed to provide evidence-based medical references for its early prevention, timely intervention, and appropriate treatment.

Methodology

The protocol of the systematic review and meta-analysis was registered in the International Prospective Register of Systematic Review (PROSPERO) with the PROSPERO ID (CRD42023463177). Relevant studies were searched to January 2024 from the databases of PubMed, Embase, Cochrane Library, and Web of Science, and the types of studies were cohort studies, case-control studies, and cross-sectional studies. Study quality was assessed using the Newcastle-Ottawa Scale (NOS) and the Cross-Sectional/Prevalence Study Quality recommended by the Agency for Healthcare Research and Quality (AHRQ). Two authors conducted studies search, data extraction, and quality assessment independently. Meta-analyses were done using Stata 14.0 software.

Results

Twelve observational studies with 3,570 spinal surgery patients were included. Ten were case-control studies, one was a cross-sectional study, and another was a cohort study, all of which were of moderate quality and above. The results of the meta-analysis showed that the incidence of new-onset SIJP after spinal surgery was 9.40%; females, no. of surgical segments, fusion to the sacrum, and postoperative pelvic tilt (PT) were significantly associated with the new-onset SIJP after spinal surgery. Meta-analyses for preoperative and postoperative controls of spondylopelvic parameters showed that postoperative lumbar lordosis (LL) in the SIJP group and postoperative LL and sacral slope (SS) of patients in the NoSIJP group had significant differences from preoperative.

Conclusion

Available evidence suggests that an increased risk of new-onset SIJP after spinal surgery is associated with sex, multi-segmental surgery, fusion to the sacrum, and greater postoperative PT.

Biomechanical Predictors of Sacroiliac Joint Uptake on Single-Photon Emission Computed Tomography/Computed Tomography

OBJECTIVE

Single-photon emission computed tomography/computed tomography (SPECT/CT) is an emerging imaging modality that identifies sites of heightened bone metabolism in response to increased stresses. The relationship between sacroiliac (SI) joint radiotracer uptake and anatomic biomechanical parameters is poorly understood.

METHODS

Adult patients with SPECT/CT scans performed at our institution between 2021 and 2023 for the workup of low back pain were included. Patient charts were reviewed for demographic factors including age, gender, and prior thoracolumbar fusion history. Biomechanical spinopelvic parameters were measured from standing scoliosis radiographs. SPECT/CT scans were reviewed for uptake at the SI joint. Patients were stratified into 2 cohorts; patients with SI uptake greater than iliac crest uptake were designated "hot," whereas those with less or equal uptake were labeled "cold."

RESULTS

One-hundred and sixty patients met inclusion criteria. Patients were slightly more male (55%) with average age 55 ± 14.9 years. Sixty-eight patients (43%) had evidence of increased SI activity. Interrater reliability showed substantial agreement (kappa = 0.62). The hot cohort demonstrated greater pelvic incidence (54.8 ± 14.0 degrees vs. 51.0 ± 11.0 degrees, P = 0.031) and pelvic tilt (20.8 ± 9.5 degrees vs. 18.4 ± 8.6 degrees, P =0.047) compared with the cold cohort. Patients were otherwise similar between cohorts (P > 0.05).

CONCLUSIONS

Increased pelvic incidence and pelvic tilt angles are associated with SPECT/CT uptake at the SI joint, which may reflect altered biomechanics at the spinopelvic junction. SPECT/CT may be a valuable tool to assess SI degeneration. Future studies are warranted to better characterize the clinical applications of these findings.

Assessing the Impact of Radiographic Realignment on Adult Spinal Deformity Patients with Sacroiliac Joint Pain at Presentation

Background: Adult spinal deformity (ASD) patients with concurrent sacroiliac joint (SIJ) pain are susceptible to worse postoperative outcomes. There is scarce literature on the impact of ASD realignment surgery on SIJ pain. Methods: Patients undergoing ASD realignment surgery were included and stratified by the presence of SIJ pain at the baseline (SIJP+) or SIJ pain absence (SIJP-). Mean comparison tests via ANOVA were used to assess baseline differences between both cohorts. Multivariable regression analyses analyzed factors associated with SIJ pain resolution/persistence, factoring in BMI, frailty, disability, and deformity. Results: A total of 464 patients were included, with 30.8% forming the SIJP+ cohort. At the baseline (BL), SIJP+ had worse disability scores, more severe deformity, higher BMI, higher frailty scores, and an increased magnitude of lower limb compensation. SIJP+ patients had higher mechanical complication (14.7 vs. 8.2%, p = 0.024) and reoperation rates (32.4 vs. 20.2%, p = 0.011) at 2 years. SIJP+ patients who subsequently underwent SI fusion achieved disability score outcomes similar to those of their SIJ- counterparts. Multivariable regression analysis revealed that SIJP+ patients who were aligned in the GAP lordosis distribution index were more likely to report symptom resolution at six weeks (OR 1.56, 95% CI: 1.02-2.37, p = 0.039), 1 year (OR 3.21, 2.49-5.33), and 2 years (OR 3.43, 2.41-7.12). SIJP- patients who did not report symptom resolution by 1 year and 2 years were more likely to demonstrate PI-LL > 5° (OR 1.36, 1.07-2.39, p = 0.045) and SVA > 20 mm (OR 1.62, 1.24-1.71 p = 0.017). Conclusions: SIJ pain in ASD patients may result in worsened pain and disability at presentation. Symptom resolution may be achieved in affected patients by adequate postoperative lumbar lordosis restoration.

[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.

Minimally invasive fusion surgery for patients with degenerative spondylolisthesis and severe lumbar spinal stenosis: a comparative study between MIDLIF and TLIF

PURPOSE

This study aims to compare midline lumbar interbody fusion (MIDLIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for treatment of patients with severe stenosis and lumbar degenerative spondylolisthesis (DS), focusing on dural tears rates, other complications, clinical and radiological outcomes.

METHODS

This cohort study included patients with severe lumbar spinal stenosis (Shizas C or D) and lumbar DS who underwent MIDLIF or MIS-TLIF. Propensity score matching was done and the groups were compared regarding surgery time, length of stay, perioperative complications, clinical results and radiological outcomes, at 1 year of follow-up.

RESULTS

The study included initially 80 patients, and 72 patients after matching, 36 in each group. Six patients had dural tears, four in the MIDLIF group and two in the MIS-TLIF group (p = 0.67). General complication rates and reoperations were not significantly different between the groups. Good or excellent clinical was achieved in 75% of the MIDLIF patients and 72% of the MIS-TLIF patients (p = 0.91). Radiological parameters showed small but statistically significant (p < 0.01) improvements after surgery, particularly in segmental lordosis and lumbar lordosis (2.0° and 1.7°), while pelvic tilt and global tilt decreased (1.6° and 2.6°). These findings were similar for both groups.

CONCLUSION

Our study confirms that MIDLIF is a safe and reliable minimally invasive alternative for lumbar interbody fusion in DS, even in patients with severe stenosis and previous spine surgery. It seems to offer similar results to MIS-TLIF regarding clinical results, radiological outcomes and complications.

The Effect of Posterior Lumbar Interbody Fusion in Lumbar Spine Stenosis with Diffuse Idiopathic Skeletal Hyperostosis: A Finite Element Analysis

OBJECTIVE

Lumbar spinal canal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH) can require revision surgery because of the intervertebral instability after decompression. However, there is a lack of mechanical analyses for decompression procedures for LSS with DISH.

METHODS

This study used a validated, three-dimensional finite element model of an L1-L5 lumbar spine, L1-L4 DISH, pelvis, and femurs to compare the biomechanical parameters (range of motion [ROM], intervertebral disc, hip joint, and instrumentation stresses) with an L5-sacrum (L5-S) and L4-S posterior lumbar interbody fusion (PLIF). A pure moment with a compressive follower load was applied to these models.

RESULTS

ROM of L5-S and L4-S PLIF models decreased by more than 50% at L4-L5, respectively, and decreased by more than 15% at L1-S compared with the DISH model in all motions. The L4-L5 nucleus stress of the L5-S PLIF increased by more than 14% compared with the DISH model. In all motions, the hip stress of DISH, L5-S, and L4-S PLIF had very small differences. The sacroiliac joint stress of L5-S and L4-S PLIF models decreased by more than 15% compared with the DISH model. The stress values of the screws and rods in the L4-S PLIF model was higher than in the L5-S PLIF model.

CONCLUSIONS

The concentration of stress because of DISH may influence adjacent segment disease on the nonunited segment of PLIF. A shorter-level lumbar interbody fixation is recommended to preserve ROM; however, it should be used with caution because it could provoke adjacent segment disease.

Sacroiliac Joint Degeneration and Pain After Spinal Arthrodesis: A Systematic Review

STUDY DESIGN

This was a systematic review.

OBJECTIVE

The present study aims to review the available literature concerning sacroiliac joint (SIJ) pain and degeneration after lumbosacral fixation to identify the prevalence and potential risk factors.

SUMMARY OF BACKGROUND DATA

Although numerous factors can predispose patients to SIJ degeneration and pain various clinical studies indicate lumbosacral arthrodesis as a major cause.

MATERIALS AND METHODS

The PubMed-MEDLINE, Cochrane Central Registry of Controlled Trials, and Embase Biomedical database were searched. Peer-reviewed comparative studies, cohort studies, case series studies and case control studies, conducted either in a retrospective or prospective design, that registered data about SIJ pain and degeneration after lumbosacral fixation were included.

RESULTS

Twenty-one studies including 2678 patients met the inclusion criteria. The percentage of SIJ pain after lumbosacral fixation diagnosed with injections and physical examination varied widely, from 3% to 90%. Among patients who underwent spinal fusion, SIJ pain prevalence was higher when arthrodesis was fixed compared with floating fusions (59% vs. 10%, P -value >0.05). The prevalence of SIJ degenerative changes at computed tomography scan was more frequent in patients who underwent spinal arthrodesis than in those who did not (75% vs. 38.2%, P -value ≤0.05).

CONCLUSION

According to current evidence, patients who received lumbosacral fixation are at risk of SIJ pain. Number of fused levels, involvement of pelvis or sacrum in the arthrodesis area, inadequate lumbosacral sagittal alignment, and site of bone graft harvesting could be possible risk factor leading to sacroiliac degeneration and pain after lumbar spine fixation that should be investigated by physicians. However, there is a lack of homogeneity of the studies that address the problem, therefore, further prospective comparative studies, with a homogeneous architecture and cohorts are needed.

LEVEL OF EVIDENCE

Level III.

New Onset Sacroiliac Joint Pain After Transforaminal Interbody Fusion: What Are the Culprits?

STUDY DESIGN

A retrospective case-control study.

OBJECTIVE

Only a few studies have studied the incidence of new-onset SI joint pain following lumbar spine fusion surgery. We aimed to explore the association between new-onset SI joint pain following Transforaminal Lumbar Interbody Fusion (TLIF) for degenerative spine disorders and changes in spinopelvic parameters.

METHODS

A retrospective review of hospital records and imaging database of a tertiary care institute was done for patients who underwent TLIF from October 2018 to October 2019. The 354 patients who satisfied the eligibility criteria were divided into 2 groups(Group A, new-onset SI joint pain group, n = 34 and Group B, normal controls, n = 320). Symptomatic relief (>70% reduction in the VAS [Visual Analogue Scale] score) after 15 minutes of SI joint injection was considered diagnostic of SI joint pain. Clinical and radiological spinopelvic parameters were compared between the 2 groups.

RESULTS

Patients with postoperative SI joint pain (Group A) had significantly less preoperative and postoperative lumbar lordosis (p < 0.001) compared to the other group. Most of the patients in Group A had a cephalad migration of the apex postoperatively (30/34 patients) whereas majority of patients in group B had either predominant caudal migration (44/320 patients) or no migration of the lumbar apex (272/320 patients).

CONCLUSIONS

The preoperative and postoperative lumbar lordosis are significantly less and the postoperative pelvic tilt is significantly high in patients with new-onset SI joint pain compared to the control group. The cephalad migration of the lumbar apex is significantly associated with new-onset SI joint pain.

Incidence of sacroiliac joint pain after lumbosacral spine fusion: A systematic review

OBJECTIVES

To determine the incidence of sacroiliac joint (SIJ) pain after lumbosacral spinal fusion.

BACKGROUND

Persistent low back pain is a potential source of disability and poor outcomes following lumbar spine fusion. The SIJ has been described as a potential source. However, there is a paucity of data concerning its importance.

METHODS

This is a PROSPERO registered systematic review. A systematic search of the English literature was performed in Medline, Embase and Cochrane Library databases. MeSH terms such as Lumbar vertebrae, Sacrum, Spinal Fusion, Pain, Sacrum, Ligaments, Sacroiliac Joint were utilized for the search. Key words such as "sacroiliac dysfunction.mp." and "sacroiliac complex.mp." were utilized for the search. Two independent reviewers reviewed articles to determine eligibility for final review and analysis. The Newcastle-Ottawa Scale was used to appraise the quality of all nonrandomized observational studies. Inverse variance weighting with random effects was used to pool data. The GRADE approach, PRISMA workflow and checklists was performed.

RESULTS

Twelve studies were included. All studies were observational and of moderate to low quality. The pooled incidence of sacroiliac joint pain was 15.8%. The pooled incidence of SIJ pain for patients without fusion extending to the sacrum was 15.8%. The pooled incidence of SIJ pain for patients with fusion extending to the sacrum was 32.9%. There was high heterogeneity.

CONCLUSION

SIJ pain is a potential cause of persistent pain after lumbar spine surgery. The current literature of poor quality. Patients presenting with pain after lumbosacral spine fusion should be evaluated for SIJ related pain.

Radiological and clinical outcomes of midline lumbar fusion on sagittal lumbar-pelvic parameters for degenerative lumbar diseases

BACKGROUND

Improving the sagittal lumbar-pelvic parameters after fusion surgery is important for improving clinical outcomes. The impact of midline lumbar fusion (MIDLF) on sagittal lumbar-pelvic alignment for the management of degenerative lumbar diseases is still unknown.

AIM

To analyze the effects of short-segment MIDLF and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) on sagittal lumbar-pelvic parameters.

METHODS

We retrospectively analyzed 63 patients with degenerative lumbar diseases who underwent single-segment MIDLF or MIS-TLIF. The imaging data of patients were collected before surgery and at the final follow-up. The radiological sagittal parameters included the lumbar lordosis (LL), lower LL, L4 slope (L4S), L5 slope (L5S), L5 incidence (L5I), L1 axis and S1 distance (LASD), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and PI-LL mismatch (PI-LL). Additionally, the clinical outcomes, including lower back and leg pain visual analog scale (VAS) and Oswestry disability index (ODI) scores, were also analyzed.

RESULTS

In both groups, LL and Lower LL significantly increased, while L5I and LASD significantly decreased at the final follow-up compared to that recorded prior to operation (P < 0.05). In the MIDLF group, L4S significantly decreased compared to that recorded prior to operation (P < 0.05), while the mean SS significantly increased and the PT significantly decreased compared to that recorded prior to operation (P < 0.05). In the MIS-TLIF group, SS slightly increased and the mean PT value decreased compared to that recorded prior to operation, but without a statistically significant difference (P > 0.05). However, the PI-LL in both groups was significantly reduced compared to that recorded prior to operation (P < 0.05). There was no significant difference in the sagittal lumbar-pelvic parameters between the two groups prior to operation and at the final follow-up (P > 0.05). In addition, the change in sagittal lumbar-pelvic parameters did not differ significantly, except for ΔLASD within the two groups (P > 0.05). The mean lower back and leg pain VAS and ODI scores in both groups were significantly improved three months after surgery and at the final follow-up. Though the mean ODI score in the MIDLF group three months after surgery was slightly higher than that in the MIS-TLIF group, there was no significant difference between the two groups at the final follow-up.

CONCLUSION

Short-segment MIDLF and MIS-TLIF can equally improve sagittal lumbar parameters such as LL, Lower LL, L5I, and LASD in the treatment of lumbar degenerative diseases. However, MIDLF had a larger impact on pelvic parameters than MIS-TLIF.

Does Interbody Cage Lordosis and Position Affect Radiographic Outcomes After Single-level Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The objective of this study was to determine if the degree of interbody cage lordosis and cage positioning are associated with changes in postoperative sagittal alignment after single-level transforaminal lumbar interbody fusion (TLIF).

SUMMARY OF BACKGROUND DATA

Ideal sagittal alignment and lumbopelvic alignment have been shown to correlate with postoperative clinical outcomes. TLIF is one technique that may improve these parameters, but whether the amount of cage lordosis improves either segmental or lumbar lordosis (LL) is unknown.

METHODS

A retrospective review was performed on patients who underwent single-level TLIF with either a 5-degree or a 12-degree lordotic cage. LL, segmental lordosis (SL), disk height, center point ratio, cage position, and cage subsidence were evaluated. Correlation between center point ratio and change in lordosis was assessed using the Spearman correlation coefficient. Secondary analysis included multiple linear regression to determine independent predictors of change in SL.

RESULTS

A total of 126 patients were included in the final analysis, with 51 patients receiving a 5-degree cage and 75 patients receiving a 12-degree cage. There were no differences in the postoperative minus preoperative LL (∆LL) (12-degree cage: -1.66 degrees vs. 5-degree cage: -2.88 degrees, P =0.528) or ∆SL (12-degree cage: -0.79 degrees vs. 5-degree cage: -1.68 degrees, P =0.513) at 1-month follow-up. Furthermore, no differences were found in ∆LL (12-degree cage: 2.40 degrees vs. 5-degree cage: 1.00 degrees, P =0.497) or ∆SL (12-degree cage: 1.24 degrees vs. 5-degree cage: 0.35 degrees, P =0.541) at final follow-up. Regression analysis failed to show demographic factors, cage positioning, or cage lordosis to be independent predictors of change in SL. No difference in subsidence was found between groups (12-degree cage: 25.5% vs. 5-degree cage: 32%, P =0.431).

CONCLUSION

Lordotic cage angle and cage positioning were not associated with perioperative changes in LL, SL, or cage subsidence after single-level TLIF.

LEVEL OF EVIDENCE

Level III.

The degenerative changes of the sacroiliac joint after S2 alar-iliac screw placement

OBJECTIVE

The goal of this study was to investigate clinical outcomes and risk factors for the progression of sacroiliac joint (SIJ) degeneration and bone formation after S2 alar-iliac screw (S2AIS) insertion.

METHODS

Using preoperative and follow-up CT scan findings (median follow-up 26 months, range 16-43 months), the authors retrospectively studied 100 SIJs in 50 patients who underwent S2AIS placement. The authors measured the progression of SIJ degeneration and bone formation after S2AIS insertion, postoperative new-onset SIJ pain, S2AIS-related reoperation, and instrumentation failures. Stepwise multivariate logistic regression modeling was performed to clarify the risk factors associated with the progression of SIJ degeneration.

RESULTS

Significant progression of SIJ degeneration was observed in 10% of the group with preoperative SIJ degeneration (p = 0.01). Bone formation was observed in 6.9% of joints. None of the patients with these radiographic changes had new-onset SIJ pain or underwent reoperation related to instrumentation failures. Multivariate logistic regression analysis revealed that preoperative SIJ degeneration (p < 0.01) and a young age at surgery (p = 0.03) significantly affected the progression of SIJ degeneration.

CONCLUSIONS

The progression of SIJ degeneration and bone formation neither led to major screw-related complications nor affected the postoperative clinical course during the median follow-up period of 26 months. Although S2AIS insertion is a safe procedure for most patients, the results of this study suggested that preoperative degeneration and younger age at surgery affected SIJ degeneration after S2AIS insertion. Further long-term observation may reveal other effects of S2AIS insertion on SIJ degeneration.

Endoscopic Lumbar Interbody Fusion and Minimally Invasive Transforaminal Lumbar Interbody Fusion for the Treatment of Lumbar Degenerative Diseases: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare clinical efficacy and safety of endoscopic lumbar interbody fusion (Endo-LIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in treatment of lumbar degenerative diseases.

METHODS

A literature search was performed using PubMed, Embase, Web of Science, and Cochrane Library databases. Studies published up to November 15, 2020, that compared Endo-LIF with MIS-TLIF for treating lumbar degenerative diseases were retrieved. Data were extracted according to predefined clinical outcome measures. Primary outcomes were preoperative and postoperative visual analog scale for leg and back pain and Oswestry Disability Index scores. Secondary outcomes were operative time and intraoperative blood loss; length of hospitalization; and complication, reoperation, and fusion rates. Data analysis was conducted with statistical software.

RESULTS

The meta-analysis included 6 studies comprising 480 patients. Results of the merged analysis revealed similar complication, reoperation, and fusion rates and preoperative and postoperative visual analog scale for leg and back pain and Oswestry Disability Index scores (P > 0.05) for Endo-LIF and MIS-TLIF. Nevertheless, with the exception of longer operative time (P < 0.05), Endo-LIF compared favorably with MIS-TLIF, with less intraoperative blood loss, shorter hospital stay (P < 0.05), and better long-term functional outcome.

CONCLUSIONS

Based on the evidence provided by this study, there is no significant difference in clinical efficacy and safety between Endo-LIF and MIS-TLIF in the treatment of lumbar degenerative diseases. Although Endo-LIF has a longer operative time, it has the advantages of less tissue trauma and rapid recovery after operation.

International Society for the Advancement of Spine Surgery Policy 2020 Update-Minimally Invasive Surgical Sacroiliac Joint Fusion (for Chronic Sacroiliac Joint Pain): Coverage Indications, Limitations, and Medical Necessity

The index 2014 International Society for the Advancement of Spine Surgery Policy Statement-Minimally Invasive Surgical Sacroiliac Joint Fusion-was generated out of necessity to provide an International Classification of Diseases, Ninth Revision (ICD-9)-based background and emphasize tools to ensure correct diagnosis. A timely ICD-10-based 2016 update provided a granular threshold selection with improved level of evidence and a more robust and relevant database (Appendix Table A1). As procedures and treatment options have evolved, this 2020 update reviews and analyzes the expanding evidence base and provides guidance relating to differences between the lateral and dorsal surgical procedures for minimally invasive surgical sacroiliac joint fusion.

Sacropelvic Fixation With S2 Alar Iliac Screws May Prevent Sacroiliac Joint Pain After Multisegment Spinal Fusion

STUDY DESIGN

A retrospective study.

OBJECTIVE

To examine the postoperative incidence of sacroiliac joint pain (SIJP) at the lower fusion level following multisegment fusion.

SUMMARY OF BACKGROUND DATA

Recently, multisegment fusion is being increasingly performed. While proximal junctional kyphosis (PJK) commonly develops following multisegment fusion, SIJP also commonly occurs following this surgery. In surgery for adult spinal deformity, fixation is often extended to the pelvis to include the sacroiliac joint. Therefore, the question of whether SIJP occurs in such cases is interesting. Here, we examined postoperative incidence of SIJP at the lower fusion level, including the incidence of PJK, and postoperative lumbopelvic alignment.

METHODS

Participants included 77 patients who underwent corrective fusion (≥3 segments). Patients were divided into three groups based on the lower fixation end: L5 (L5), S (sacrum), and P (pelvis). In the P group, an S2 alar iliac screw was used. Postoperative incidence of SIJP and PJK in each group was examined along with lumbopelvic parameters.

RESULTS

SIJP incidence was 16.7%, 26.1%, and 4.2% in the L5, S, and P groups, respectively, indicating the highest value in the S group and a significantly lower value in the P group. PJK incidence was 23.3%, 30.4%, and 29.2% in the L5, P, and S groups, respectively, with no significant differences. Regarding postoperative lumbopelvic parameters, there was no significant difference between the groups; however, lumbar lordosis tended to be better in the P group.

CONCLUSION

SIJP incidence was extremely high with fixation to the sacrum, and in the group with fixation to the pelvis, there was hardly any SIJP. Sacropelvic fixation using S2 alar iliac screws could prevent SIJP onset following multisegment fusion.

LEVEL OF EVIDENCE

3.

Incidence, diagnosis and management of sacroiliitis after spinal surgery: a systematic review of the literature

The sacroiliac joint (SIJ) is a possible source of persistent or new onset pain after lumbar or lumbosacral fusion. The aim of this paper is to systematically review and analyze the available literature related to the incidence, diagnosis and management of sacroiliitis after spinal arthrodesis. The authors independently screened the titles and abstracts of all articles identified concerning sacroiliac joint pain after lumbar or lumbosacral fusion, to assess their suitability to the research focus. The average incidence of sacroiliitis after lumbar or lumbosacral arthrodesis was found to be 37 ± 28.48 (range 6-75), increasing directly to the number of fused segments involved, especially when the sacrum is included. The most accurate evaluation is the image-guided injection of anesthetic solutions in the joint. Surgery treatment may be considered when conservative therapy fails, with open surgery or with minimally invasive SIJ fusion. Although the risk of developing SIJ degeneration is unclear, the results indicate that pain and degeneration of SIJ develop more often in patients undergoing lumbosacral fusion regardless of the number of melting segments. The treatment of sacroiliitis appears to be independent of his etiology, with or without previous instrumentation on several levels.

Spinal Balance/Alignment - Clinical Relevance and Biomechanics

In the normal spine due to its curvature in various regions, C7 plumb line (C7PL) passes through the sacrum so that the head is centered over the pelvis-ball and socket hip joints and ankle joints. This configuration leads to the least muscular activities to maintain the spinal balance. For any reason like deformity, scoliosis, kyphosis, trauma, and/or surgery this optimal configuration gets disturbed requiring higher muscular activity to maintain the posture and balance. Several parameters like the thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), Hip- and leg position influence the sagittal balance and thus the optimal configuration of spinal alignment. Global sagittal imbalance is energy consuming and often painful compensatory mechanisms are developed, that in turn negatively influence the quality of life. This review looks at the clinical aspects of spinal imbalance, and the biomechanics of spinal balance as dictated by the deformities- ankylosing spondylitis, scoliosis and kyphosis; surgical corrections- pedicle subtraction osteotomies and long segment stabilizations and consequent postural complications like the proximal and distal junctional kyphosis. This review suggests several potential research topics as well.

Sagittal Balance Correction Following Lumbar Interbody Fusion: A Comparison of the Three Approaches

STUDY DESIGN

Retrospective cohort study.

PURPOSE

The objective of this study was to compare three widely used interbody fusion approaches in regard to their ability to correct sagittal balance, including pelvic parameters.

OVERVIEW OF LITERATURE

Restoration of sagittal balance in lumbar spine surgery is associated with better postoperative outcomes. Various interbody fusion techniques can help to correct sagittal balance, with no clear consensus on which technique offers the best correction.

METHODS

The charts and imaging of patients who have undergone surgery through either open transforaminal lumbar interbody fusion (TLIF), minimally invasive TLIF (MIS TLIF), or oblique lumbar interbody fusion (OLIF) were retrospectively reviewed. The following sagittal balance parameters were measured pre- and postoperatively: segmental lordosis, lumbar lordosis, disk height, pelvic tilt, and pelvic incidence. Data on postoperative complications were gathered.

RESULTS

Only OLIF managed to significantly improve segmental lordosis (4.4°, p <0.001) and lumbar lordosis (4.8°, p =0.049). All approaches significantly augmented disk height, with OLIF having the greatest effect (3.7°, p <0.001). No approaches were shown to significantly correct pelvic tilt. Pelvic incidence remained unchanged in all approaches. Open TLIF was the only approach with a higher rate of postoperative complications (33%, p =0.009).

CONCLUSIONS

The OLIF approach might offer greater correction of sagittal balance over open and MIS TLIF, mainly in regard to segmental lordosis, lumbar lordosis, and disk height. MIS TLIF, although offering more limited access than open TLIF, was not inferior to open TLIF in regard to sagittal balance correction. A higher rate of complications was shown for open TLIF than the other approaches, possibly due to its more invasive nature.

The association between sacroiliac joint-related pain following lumbar spine surgery and spinopelvic parameters: a prospective multicenter study

PURPOSE

To prospectively calculate the incidence of postoperative sacroiliac joint-related pain (SIJP) and investigate the association between spinopelvic parameters and postoperative SIJP after lumbar spine surgery.

METHODS

We prospectively enrolled consecutive patients who underwent lumbar spine surgery. We defined postoperative SIJP as unilateral buttock pain according to fulfillment of the following criteria within 3 months of the surgery: a sacroiliac joint (SIJ) score higher than 4/9 postoperatively; positive response to analgesic periarticular SIJ injection with fluoroscopy; no other complications related to the surgery. The patients were divided into the SIJP group and non-SIJP group. We compared the background information and analyzed the differences in spinopelvic parameters in both groups. Additionally, receiver-operating characteristic curve analyses were performed to evaluate the cutoff values of spinopelvic parameters.

RESULTS

Of the 281 patients enrolled, 265 were included and eight developed postoperative SIJP (3.0%). There were no significant differences in the background information between groups. Preoperative and postoperative radiological evaluations revealed that the pelvic incidence (PI) in the SIJP group was significantly higher than that in the non-SIJP group, and there were no significant differences in lumbar lordosis (LL), pelvic tilt, sacral slope, and PI minus LL. For preoperative PI, the area under the curve, cutoff value, sensitivity, and specificity were 0.73739, 59, 62.5%, and 81.9%, respectively.

CONCLUSIONS

The incidence of postoperative SIJP after lumbar spine surgery was 3.0%. Higher PI values were associated with a higher risk of postoperative SIJP. These slides can be retrieved under Electronic Supplementary Material.

Retrospective Assessment of Early Changes in the Sacroiliac Joint After Posterior Lumbar Fusion Surgery via Magnetic Resonance Imaging and Computed Tomography

OBJECTIVES

The need for lumbar-lumbosacral fusion surgery has increased in the recent decade. Although this type of surgical approach has been reported to provide better improvement in low back pain compared with conventional conservative treatments, the ratio of failure varies between 5% and 30% in different studies.

METHODS

This retrospective study was conducted through screening patient files between January 2013 and January 2016. Preoperative and postoperative neurologic examination, Visual Analogue Scale, Oswestry Disability Index, and medical and surgical treatments of 66 patients were evaluated.

RESULTS

The data from these 66 patients was included in this study. Of the patients, 28 were male and 38 were female. Mean age was 58.3 years for male and 60.1 years for female subjects. Mean duration of follow-up was 15 months.

CONCLUSIONS

Our study has revealed that lumbosacral fusion surgery increases sacroiliac joint degeneration. We consider that magnetic resonance imaging is superior to computed tomography for detection of early stage sacroiliac joint degeneration.

Motion preservation following total lumbar disc replacement at the lumbosacral junction: a prospective long-term clinical and radiographic investigation

BACKGROUND CONTEXT

Total lumbar disc replacement (TDR) intends to avoid fusion-related negative side effects by means of motion preservation. Despite their widespread use, the adequate quality and quantity of motion, as well as the correlation between radiographic data with the patient's clinical symptomatology, remains to be established. Long-term data are lacking in particular.

PURPOSE

This study aimed to perform a clinical and radiographic long-term investigation following TDR with special emphasis on motion preservation assessment and to establish any potential correlation with patient-reported outcome parameters.

STUDY DESIGN/SETTING

A prospective, single-center, clinical, and radiological investigation following TDR with ProDisc II (Synthes, Paoli, PA, USA) was carried out.

PATIENT SAMPLE

Patients with a minimum 5-year follow-up (FU) after TDR performed for the treatment of intractable and predominant (≥80%) axial low back pain resulting from single-level degenerative disc disease without instabilities or deformities at the lumbosacral junction (L5-S1) comprised the sample.

OUTCOME MEASURES

Visual analogue scale (VAS), Oswestry Disability Index (ODI), and patient satisfaction rates (three-scale outcome rating), range of motion (ROM) at the index- and cranially adjacent level as well as segmental lumbar lordosis (SLL) and global lumbar lordosis (GLL) were the outcome measures.

METHODS

All data were acquired within the framework of an ongoing prospective clinical trial. Patients were examined preoperatively, 3, 6, and 12 months postoperatively, and annually thereafter. X-rays were performed in antero-posterior and lateral views as well as functional flexion/extension images. Radiological examinations included ROM at the index and cranially adjacent level as well as SLL and GLL. X-ray measurements were correlated with the clinical outcome parameters. A longitudinal analysis was performed between baseline data with those from the early (3-6 months), mid- (12-24 months), and late FU stages (≥5 years).

RESULTS

Results from 51 patients with a mean FU of 7.8 years (range 5.0-13.3 years) were available for the final analysis. X-ray measurements revealed a maintained mobility with a trend toward gradually declining ROM values. Although no statistically significant difference in ROM was detected between the preoperative and early FU (6.8° vs. 5.8°, p=.1), a further reduction in ROM became statistically significant at the mid- and final FU, with mean ROM of 5.2° and 4.4°, respectively (p<.001). Global lumbar lordosis increased from 48.8° to 54.4° (p<.0001) which was attributed to a lordotic shift from 18.2° to 28.0° at the index segment (p<.00001) and which was positively correlated with the applied implant lordosis (p<.05). A compensatory reduction of lordosis was observed at the cranially adjacent segment (p<.0001). The mobility of the cranially adjacent level remained unchanged (p>.05). The clinical outcome scores (VAS, ODI) revealed a significant improvement from baseline levels (p<.05). The reduction in ROM was not negatively correlated with the patient's clinical symptomatology (p>.05).

CONCLUSION

The present data reveal an increased GLL resulting from a lordotic shift of the index segment, which was strongly correlated with the applied implant lordosis. This lordotic shift was accompanied by a compensatory reduction of lordosis at the cranially adjacent segment. A gradual and statistically significant decline of the device mobility was noted over time which, however, did not negatively impact the patient's clinical symptomatology. Although the present long-term investigation provides additional insight into longitudinal radiographic changes and their influence on the patient's clinical symptomatology following TDR, the adequate quality and quantity of motion with artificial motion-preserving implants remains to be established, which will aid in defining more refined treatment concepts for both fusion and motion preserving techniques alike.

Sacroiliac joint syndrome 10 years after lumbar arthroplasty: the importance of spinopelvic alignment

INTRODUCTION

Sagittal balance is an independent predictor of outcomes in spinal care and several authors focused their attention on the lumbar lordosis restoration as the key point to prevent secondary sacroiliac joint dysfunction (SIJD) after fusion. On the other hand, lumbar disc arthroplasty allows preservation of motion avoiding increased stress on the spinopelvic junction and preventing iatrogenic sagittal imbalance.

METHODS

We analyze the incidence of a secondary SIJD and the spinopelvic alignment on a series of 31 consecutive lumbar disc prosthesis with a 10-year follow-up.

RESULTS

Sagittal balance assessment showed no significant variation of preoperative spinopelvic parameters. Four patients (12 %) presented a symptomatic SIJD. Only two of them required a percutaneous SIJ fixation. Both of them presented a fused L5-S1 prosthesis.

CONCLUSIONS

The low rate of SIJD 10 years after lumbar arthroplasty might be explained by the preservation of the spinopelvic balance.

Sagittal sacropelvic morphology and balance in patients with sacroiliac joint pain following lumbar fusion surgery

OBJECTIVE

To investigate the sagittal sacropelvic morphology and balance of the patients with SIJ pain following lumbar fusion.

METHODS

Among 452 patients who underwent posterior lumbar interbody fusion between June 2009 and January 2013, patients with postoperative SIJ pain, being responded to SIJ block were enrolled. For a control group, patients matched for sex, age group, the number of fused level and fusion to sacrum were randomly selected. Patients were assessed radiologic parameters including lumbar lordosis, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). To evaluate the sagittal sacropelvic morphology and balance, the ratio of PT/PI, SS/PI and PT/SS were analyzed.

RESULTS

A total of 28 patients with SIJ pain and 56 patients without SIJ pain were assessed. Postoperatively, SIJ pain group showed significantly greater PT (p=0.02) than non-SIJ pain group. Postoperatively, PT/PI and SS/PI in SIJ pain group was significantly greater and smaller than those in non-SIJ pain group respectively (p=0.03, 0.02, respectively) except for PT/SS (p=0.05). SIJ pain group did not show significant postoperative changes of PT/PI and SS/PI (p=0.09 and 0.08, respectively) while non-SIJ pain group showed significantly decrease of PT/PI (p=0.00) and increase of SS/PI (p=0.00).

CONCLUSION

This study presents different sagittal sacropelvic morphology and balance between the patients with/without SIJ pain following lumbar fusion surgery. The patients with SIJ pain showed retroversed pelvis and vertical sacrum while the patients without SIJ pain have similar morphologic features with asymptomatic populations in the literature.