Spinopelvic Parameters in the Elderly: Does Inadequate Correction Portend Worse Outcomes?

Introduction: This study aimed to compare the outcomes of corrective fusion for adult spinal deformity (ASD) in older people using two different sagittal correction goals: the conventional formula of "pelvic incidence (PI)-lumbar lordosis (LL) mismatch <10°" and an undercorrection strategy based on the range of 10°≤PI-LL≤20°. Methods: A total of 102 consecutive patients (11 male and 91 female patients; mean age, 72.0 years) aged above 65 years with scoliosis >20° or LL<20° who had undergone long-segment fusion from the lower thoracic spine to the pelvis for ASD and had been followed-up for a minimum of two years at our institution since March 2013 were included in this retrospective study. After excluding patients with PI-LL≤-10° on postoperative standing radiographs, the remaining patients were divided into two groups: 31 patients with 10°≤PI-LL≤20° (U group) and 63 patients with -10°

Comparative Evaluation of Postoperative Epidural Hematoma after Lumbar Microendoscopic Laminotomy: The Utility of Ultrasonography versus Magnetic Resonance Imaging.

Introduction: Postoperative spinal epidural hematoma (PSEH) is a severe complication of spinal surgery that necessitates accurate and timely diagnosis. This study aimed to assess the accuracy of ultrasonography as an alternative diagnostic tool for PSEH after microendoscopic laminotomy (MEL) for lumbar spinal stenosis, comparing it with magnetic resonance imaging (MRI). Methods: A total of 65 patients who underwent MEL were evaluated using both ultrasound- and MRI-based classifications for PSEH. Intra- and interrater reliabilities were analyzed. Furthermore, ethical standards were strictly followed, with spine surgeons certified by the Japanese Orthopaedic Association performing evaluations. Results: Among the 65 patients, 91 vertebral segments were assessed. The intra- and interrater agreements for PSEH classification were almost perfect for both ultrasound (κ=0.824 [95% confidence interval (CI) 0.729-0.918] and κ=0.810 [95% CI 0.712-0.909], respectively) and MRI (κ=0.839 [95% CI 0.748-0.931] and κ=0.853 [95% CI 0.764-0.942], respectively). The results showed high concordance between ultrasound- and MRI-based classifications, validating the reliability of ultrasound in postoperative PSEH evaluation. Conclusions: This study presents a significant advancement by introducing ultrasound as a precise and practical alternative to MRI for PSEH evaluation. The comparable accuracy of ultrasound to MRI, rapid bedside assessments, and radiation-free nature make it valuable for routine postoperative evaluations. Despite the limitations related to specific surgical contexts and clinical outcome assessment, the clinical potential of ultrasound is evident. It offers clinicians a faster, cost-effective, and repeatable diagnostic option, potentially enhancing patient care. This study establishes the utility of ultrasound in evaluating postoperative spinal epidural hematomas after MEL. With high concordance to MRI, ultrasound emerges as a reliable, practical, and innovative tool, promising improved diagnostic efficiency and patient outcomes. Further studies should explore its clinical impact across diverse surgical scenarios.

Long-term efficacy of microendoscopic laminotomy for lumbar spinal stenosis in advanced degenerative spondylolisthesis with or without dynamic spinal instability: a propensity score-matching analysis.

OBJECTIVE: In this study, the authors aimed to determine the mid- to long-term outcomes of microendoscopic laminotomy (MEL) for lumbar spinal stenosis (LSS) with degenerative spondylolisthesis (DS) and identify preoperative predictors of poor mid- to long-term outcomes. METHODS: The authors retrospectively reviewed the medical records of 274 patients who underwent spinal MEL for symptomatic LSS. The minimum postoperative follow-up duration was 5 years. Patients were classified into two groups according to DS: those with DS (the DS+ group) and those without DS (the DS- group). The patients were subjected to propensity score matching based on sex, age, BMI, surgical segments, and preoperative leg pain visual analog scale scores. Clinical outcomes were evaluated 1 year and > 5 years after surgery. RESULTS: Surgical outcomes of MEL for LSS were not significantly different between the DS+ and DS- groups at the final follow-up (mean 7.8 years) in terms of Oswestry Disability Index (p = 0.498), satisfaction (p = 0.913), and reoperation rate (p = 0.154). In the multivariate analysis, female sex (standard ß -0.260), patients with slip angle > 5° in the forward bending position (standard ß -0.313), and those with dynamic progression of Meyerding grade (standard ß -0.325) were at a high risk of poor long-term outcomes. CONCLUSIONS: MEL may have good long-term results in patients with DS without dynamic instability. Women with dynamic instability may require additional fusion surgery in approximately 25% of cases for a period of ≥ 5 years.

Outcomes and Vertebral Osteophytes and Bulging Intervertebral Discs Occupancy as a Decision-Making Tool for Surgical Success in Patients Undergoing Microendoscopic Foraminotomy for Lumbar Foraminal Stenosis.

OBJECTIVE: The objective of this study was to determine the long-term outcomes of microendoscopic foraminotomy in treating lumbar foraminal stenosis and identify the optimal extent of decompression that yields improved results and fewer complications. METHODS: A retrospective cohort study reviewed the medical records of 95 consecutive patients who underwent microendoscopic foraminotomy for lumbar foraminal stenosis. Clinical outcomes were assessed using the Japanese Orthopaedic Association scoring system and visual analog scale for low back and leg pain. Surgical success was determined by meeting significant improvement thresholds for back and leg pain at 2 years postoperatively. Multiple regression analysis identified factors associated with improved pain scores. Receiver operating characteristic curve analysis determined the cut-off values for successful surgeries. RESULTS: Significant improvements were observed in Japanese Orthopaedic Association and visual analog scale scores for back and leg pain 2 years postoperatively compared with preoperative scores (P < 0.0001) and sustained over a ≥5-year follow-up period. Reoperation rates were low and did not significantly increase over time. Multiple regression analysis identified occupancy of the vertebral osteophytes and bulging intervertebral discs (O/D complex) as surgical success predictors. A 45.0% O/D complex occupancy cutoff value was determined, displaying high sensitivity and specificity for predicting surgical success. CONCLUSIONS: This study provides evidence supporting the long-term efficacy of microendoscopic foraminotomy for lumbar foraminal stenosis and predicting surgical success. The 45.0% O/D complex occupancy cut-off value can guide patient selection and outcome prediction. These insights contribute to informed surgical decision-making and underscore the importance of evaluating the O/D complex in preoperative planning and predicting outcomes.

Unique Characteristics of New Bone Formation Induced by Lateral Lumbar Interbody Fusion Procedure.

Introduction: Despite the absence of bone grafting in the area outside the cage, lateral bridging callus outside cages (LBC) formation is often observed here following extreme lateral interbody fusion (XLIF) conversely to conventional methods of transforaminal lumbar interbody fusion and posterior lumbar interbody fusion. The LBC, which may increase stabilization and decrease nonunion rate in treated segments, has rarely been described. This study aimed to identify the incidence and associated factors of LBC following XLIF. Methods: We enrolled 136 consecutive patients [56 males, 80 females; mean age 69.6 (42-85) years] who underwent lumbar fusion surgery using XLIF, including L4/5 level with posterior fixation at a single institution between February 2013 and February 2018. One year postoperatively, the treated L4/5 segments were divided into the LBC formation and non-formation groups. Potential influential factors, such as age, sex, body mass index, bone density, height of cages, cage material (titanium or polyetheretherketone [PEEK]), presence or absence of diffuse idiopathic skeletal hyperostosis (DISH), and radiological parameters, were evaluated. Multivariate logistic regression analysis was performed for factors significantly different from the univariate analysis. Results: The incidence of LBC formation was 58.8%. Multivariate logistic regression analysis showed that the length of osteophytes [+1 mm; odds ratio, 1.29; 95% confidence interval, 1.17-1.45; p<0.0001] was significant LBC formation predictive factors. Receiver operating characteristic curve analysis demonstrated that the cut-off value for osteophyte length was 14 mm, the sensitivity was 58.8%, the specificity was 84.4%, and the area under the ROC curve for this model was 0.79. Conclusions: The incidence of LBC formation was 58.8% in L4/5 levels one year after the XLIF procedure. We demonstrated that the length of the osteophyte was significantly associated with LBC formation.

Dynamic cord compression induced by proximal junctional failure and loose pedicle screws after thoracolumbar fusion surgery: a case report.

BACKGROUND: One of the common mechanical complications following spinal fusion surgery is proximal junctional failure (PJF). The incidence of neurological deficit associated with PJF has been poorly described in the literature. Here, we report a case in which numbness in the lower extremities was recognized as the first symptom, but the discrepancy in the imaging findings made PJF difficult to diagnose. METHODS: A 71-year-old female underwent corrective fusion surgery. Three weeks later, she complained of persistent right leg numbness. Standing X-ray showed the back-out of the pedicle screws (PSs) in the upper instrumented vertebra (UIV), but there was no obvious evidence of cord compression on computed tomography (CT), which caused the delay of diagnosis. Five weeks later, magnetic resonance image (MRI) did not show cord compression on an axial view, but there were signal changes in the spinal cord. RESULTS: The first reason for the delayed diagnosis was the lack of awareness that leg numbness could occur as the first symptom of PJF. The second problem was the lack of evidence for spinal cord compression in various imaging tests. Loosened PSs were dislocated on standing, but were back to their original position on supine position. In our case, these contradictory images led to a delay in diagnosis. CONCLUSION: Loosened PSs caused dynamic cord compression due to repeated deviation and reduction. Supine and standing radiographs may be an important tool in the diagnosis of PJF induced by dynamic cord compression.

Effect of Lumbar Fusion and Pelvic Fixation Rigidity on Hip Joint Stress: A Finite Element Analysis.

STUDY DESIGN: This study compared hip stress among different types of lumbopelvic fusion based on finite element (FE) analysis. OBJECTIVE: We believe that the number and placement of S2 alar iliac (AI) screws and whether the screws loosen likely influence hip joint stress in the FE model. SUMMARY OF BACKGROUND DATA: Spinopelvic fixation has been shown to increase the risk of progression for hip joint osteoarthritis. The biomechanical mechanism is not well understood. We hypothesize that the rigid pelvic fixation may induce stress at adjacent joints. MATERIALS AND METHODS: A three-dimensional nonlinear FE model was constructed from the L4 vertebra to the femoral bone. From the intact model, we made four fusion models, each with different lower vertebrae instrumentation: (1) intact, (2) L4-S1 fusion, (3) L4-S2 AI screw fixation, (4) L4-S2 AI screw fixation with S2 AI screw loosening, and (5) L4-S1 and dual sacral AI screw fixation. A compressive load of 400 N was applied vertically to the L4 vertebra, followed by an additional 10 Nm bending moment about different axes to simulate either flexion, extension, left lateral bending, or right axial rotation. The distal femoral bone was completely restrained. The von Mises stress and angular motion were analyzed across the hip joints within each fusion construct model. RESULTS: Hip joint cartilage stress and range of motion increased for all postures as pelvic fixation became more rigid. The dual sacral AI screw fixation model increased stress and angular motion at the hip joint more than intact model. Our results suggest that more rigid fixation of the pelvis induces additional stress on the hip joint, which may precipitate or accelerate adjacent joint disease. CONCLUSIONS: Dual sacral AI fixation led to the highest stress while loosening of S2 AI decreased stress on the hip joint. This study illustrates that more rigid fixation among lumbosacral fusion constructs increases biomechanical stress on the hip joints.

Quantitative Biomechanical Evaluation for Optimal Spinal Instrumentation to Prevent Mechanical Complications in Spinal Fusion from the Lower Thoracic Spine to the Pelvis for Adult Spinal Deformity: A Finite Element Analysis.

Introduction: Mechanical complications, such as rod fracture (RF) and proximal junctional kyphosis (PJK), commonly occur after adult spinal deformity (ASD) surgery. A rigid construct is preferred to prevent RF, whereas it is a risk factor for PJK. This controversial issue urged us to conduct a biomechanical study for seeking the optimal construct to prevent mechanical complications. Methods: A three-dimensional nonlinear finite element model, which consisted of the lower thoracic and lumbar spine, pelvis, and femur, was created. The model was instrumented with pedicle screws (PSs), S2-alar-iliac screws, lumbar interbody fusion cages, and rods. Rod stress was measured when a forward-bending load was applied at the top of the construct to evaluate the risk of RF in constructs with or without accessory rods (ARs). In addition, fracture analysis around the uppermost instrumented vertebra (UIV) was performed to assess the risk of PJK. Results: Changing the rod material from titanium alloy (Ti) to cobalt chrome (CoCr) decreased shearing stress at L5-S1 by 11.5%, and adding ARs decreased it by up to 34.3% (for the shortest ARs). Although the trajectory (straightforward vs. anatomical) of PSs did not affect the fracture load for UIV+1, changing the anchor from PSs to hooks at the UIV reduced it by 14.8%. Changing the rod material from Ti to CoCr did not alter the load, whereas the load decreased by up to 25.1% as the AR became longer. Conclusions: The PSs at the UIV in the lower thoracic spine, CoCr rods as primary rods, and shorter ARs should be used in long fusion for ASD to prevent mechanical complications.

Erratum for Lumbar Fusion including Sacroiliac Joint Fixation Increases the Stress and Angular Motion at the Hip Joint: A Finite Element Study.

[This corrects the article DOI: 10.22603/ssrr.2021-0231.].

Ultrasonography is an effective tool for the evaluation of traumatic vertebral artery injuries distal to fourth cervical vertebra in the emergency room.

BACKGROUND: This study aimed to determine the feasibility of ultrasonography in the assessment of cervical vertebral artery (VA) injury as an alternative to computed tomography angiography (CTA) in the emergency room. METHODS: We analyzed 50 VAs from 25 consecutive patients with cervical spine injury that had been admitted to our emergency room. Ultrasonography and CTA were performed to assess the VA in patients with cervical spine injury. We examined the sensitivity and specificity of ultrasonography compared with CTA. RESULTS: Among these VAs, six were occluded on CTA. The agreement between ultrasonography and CTA was 98% (49/50) with 0.92 Cohen's Kappa index. The sensitivity, specificity, and positive and negative predictive values of ultrasonography were 100%, 97.7%, 85.7%, and 100%, respectively. In one case with hypoplastic VA, the detection of flow in the VA by ultrasonography differed from detection by CTA. Meanwhile, there were two cases in which VAs entered at C5 transverse foramen rather than at C6 level. However, ultrasonography could detect the blood flow in these VAs. CONCLUSIONS: Ultrasonography had a sensitivity of 100% compared with CTA in assessment of the VA. Ultrasonography can be used as an initial screening test for VA injury in the emergency room.

Obesity in children with low back pain: implications with imaging phenotypes and opioid use.

BACKGROUND CONTEXT: Low back pain (LBP) is common in children and adolescents, carrying substantial risk for recurrence and continuation into adulthood. Studies have linked obesity to the development of pediatric LBP; however, its association with lumbar spine degeneration, alignment parameters, and opioid use remains debated. PURPOSE: Considering the increasing prevalence of pediatric obesity and LBP and the inherent issues with opioid use, this study aimed to assess the association of obesity with lumbar spine degeneration, spinopelvic alignment, and opioid therapy among pediatric patients. STUDY DESIGN/SETTING: A retrospective study of pediatric patients presenting to a single institute with LBP and no history of spine deformity, tumor, or infection was performed. PATIENT SAMPLE: A totasl of 194 patients (mean age: 16.7±2.3 years, 45.3% male) were included, of which 30 (15.5%) were obese. OUTCOME MEASURES: Prevalence of imaging phenotypes and opioid use among obese to nonobese pediatric LBP patients. Magnetic resonance and plain radiographic imaging were evaluated for degenerative phenotypes (disc bulging, disc herniation, disc degeneration [DD], high-intensity zones [HIZ], disc narrowing, Schmorl's nodes, endplate phenotypes, Modic changes, spondylolisthesis, and osteophytes). Lumbopelvic parameters including lumbar lordosis, pelvic tilt, sacral slope, pelvic incidence and pelvic incidence-lumbar lordosis (PI-LL) mismatch were also examined. METHODS: Demographic and clinical information was recorded, including use of opioids. The associations between obesity and lumbar phenotypes or opiod use were assessed by multiple regression models. RESULTS: Based on multivariate analysis, obesity was significantly associated with the presence of HIZ (adjusted OR: 5.36, 95% CI: 1.30 to 22.09). Further analysis demonstrated obesity (adjusted OR: 3.92, 95% CI: 1.49 to 10.34) and disc herniation (OR: 4.10, 95% CI: 1.50 to 11.26) were associated with opioid use, independent of duration of symptoms, other potential demographic determinants, and spinopelvic alignment. CONCLUSIONS: In pediatric patients, obesity was found to be significantly associated with HIZs of the lumbar spine, while disc herniation and obesity were associated with opioid use. Spinopelvic alignment parameters did not mitigate any outcome. This study underscores that pediatric obesity increases the risk of developing specific degenerative spine changes and pain severity that may necessitate opioid use, emphasizing the importance of maintaining healthy body weight in promoting lumbar spine health in the young.

Using Electrical Stimulation of the Ulnar Nerve Trunk to Predict Postoperative Improvement in Hand Clumsiness in Patients With Cervical Spondylotic Myelopathy.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: To investigate whether the immediate and short-term effects of preoperative electrical peripheral nerve stimulation (ePNS) on performance of the 10-second test could predict the early postoperative outcomes of patients with cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA: Previous studies have shown that early clinical improvement in CSM patients may be because of reversal of spinal cord ischemia after spinal cord compression. MATERIALS AND METHODS: We conducted a 10-second test before surgery, after ePNS, and at discharge (one week after surgery) in 44 patients with CSM who underwent C3-C7 laminoplasty and evaluated their correlations. The effects of the procedures (ePNS or operation) and sides (stimulated or nonstimulated side) for the 10-second test were analyzed using repeated measures analysis of variance. The Pearson correlation coefficient was used to measure the relationship between the 10-second test values according to the method (after ePNS vs. surgery). In addition, the Bland-Altman method was used to evaluate the degree of agreement between the 10-second test obtained after ePNS versus shortly after surgery. RESULTS: The preoperative 10-second test showed the most improvement immediately after the administration of ePNS, with a gradual decrease for the first 30 minutes after completion. After the initial 30 minutes, performance decreased rapidly, and by 60 minutes performance essentially returned to baseline. The 10-second post-ePNS had a strong positive correlation with the 10-second test in the early postoperative period (at discharge=one week after surgery). These phenomena were observed with the left hand, the side stimulated with ePNS, as well as the right hand, the side not stimulated. CONCLUSIONS: Early postoperative outcomes after CSM surgery may be predicted by the results of preoperative ePNS. LEVEL OF EVIDENCE: Level 3.

Spinopelvic fusion surgery from lower thoracic spine to pelvis increased hip joint moment-motion analysis.

PURPOSE: Spinal fusion surgery is often performed with pelvic fixation to prevent distal junctional kyphosis. The inclusion of spinopelvic fixation has been reported to induce progression of hip joint arthropathy in a radiographic follow-up study. However, its biomechanical mechanism has not yet been elucidated. This study aimed to compare the changes in hip joint moment before and after spinal fusion surgery. METHODS: This study was an observational study and included nine patients (eight women and one man) who were scheduled to undergo spinopelvic fusion surgery. We calculated the three-dimensional external joint moments of the hip during gait, standing, and climbing stairs before and 1 year after surgery. RESULTS: During gait, the maximum extension moment was 0.51 ± 0.29 and 0.63 ± 0.40 before and after spinopelvic fusion surgery (p = 0.011), and maximum abduction moment was 0.60 ± 0.33 and 0.83 ± 0.34 before and after surgery (p = 0.004), respectively. During standing, maximum extension moment was 0.76 ± 0.32 and 1.04 ± 0.21 before and after spinopelvic fusion surgery (p = 0.0026), and maximum abduction moment was 0.12 ± 0.20 and 0.36 ± 0.22 before and after surgery (p = 0.0005), respectively. During climbing stairs, maximum extension moment was - 0.31 ± 0.30 and - 0.48 ± 0.15 before and after spinopelvic fusion surgery (p = 0.040), and maximum abduction moment was 0.023 ± 0.18 and - 0.02 ± 0.13 before and after surgery (p = 0.038), respectively. CONCLUSION: This study revealed that hip joint flexion-extension and abduction-adduction moments increased after spinopelvic fixation surgery in the postures of standing, walking, and climbing stairs. The mechanism was considered to be adjacent joint disease after spinopelvic fusion surgery including sacroiliac joint fixation.

Clinical and radiographic characteristics of increased signal intensity of the spinal cord at the vertebral body level in patients with cervical myelopathy.

BACKGROUND: Increased signal intensity (ISI) is usually recognized at the disc level of the responsible lesion in the patients with cervical myelopathy. However, it is occasionally seen at the vertebral body level, below the level of compression. We aimed to investigate the clinical significance and the radiographic characteristics of ISI at the vertebral body level. METHODS: This retrospective study included 135 patients with cervical spondylotic myelopathy who underwent surgery and with local ISI. We measured the local and C2-7 angle at flexion, neutral, and extension. We also evaluated the local range of motion (ROM) and C2-7 ROM. The patients were classified into group D (ISI at disc level) and group B (ISI at vertebral body level). RESULTS: The prevalence was 80.7% (109/135) and 19.3% (26/135) for groups D and B, respectively. Local angle at flexion and neutral were more kyphotic in group B than in group D. The local ROM was larger in group B than in group D. Moreover, C2-7 angle at flexion, neutral and extension were more kyphotic in group B than in group D. Two years later, local angle at flexion, neutral, and extension were also kyphotic in group B than group D; however, local and C2-7 ROM was not significantly different between the two groups. There was no significant difference of clinical outcomes 2 years postoperatively between both groups. CONCLUSIONS: Group B was associated with the kyphotic alignment and local greater ROM, compared to group D. As the spinal cord is withdrawn in flexion, the ISI lesion at vertebral body might be displaced towards the disc level, which impacted by the anterior components of the vertebrae. ISI at the vertebral body level might be related to cord compression or stretching at flexion position. This should be different from the conventionally held pincer-mechanism concept.

Posterior Epidural Migrated Lumbar Disc Fragment at L2-3 Level Mimicking an Extradural Spinal Tumor: A Case Report.

Introduction: Disc sequestration is well known as a perforation of the fibrous ring and posterior longitudinal ligament, and migration of the fragment to the epidural space. Case Report: A 62-year-old man complained of increased pain and hypoesthesia and muscle weakness of the left lower limb that had started 1 month before. Magnetic resonance imaging revealed a tumor-like mass at the L2-3 level on the posterior side of the dura. The fragment was strongly adhered to the dural sac and was resected piece by piece. Disc herniation recognized at L2-3 compressed the left L3 nerve root and was removed. The histopathological diagnosis was consistent with a degenerated intervertebral disc. All symptoms improved after the surgery. Conclusion: There are few reports about the posterior migrated disc herniation at higher lumbar level. It may be associated with fused segments from L4 to the pelvis due to the previous surgery, which impacted the adjacent segment.

Lumbar Fusion including Sacroiliac Joint Fixation Increases the Stress and Angular Motion at the Hip Joint: A Finite Element Study.

Introduction: Adult spinal fusion surgery improves lumbar alignment and patient satisfaction. Adult spinal deformity surgery improves saggital balance not only lumbar lesion, but also at hip joint coverage. It was expected that hip joint coverage rate was improved and joint stress decreased. However, it was reported that adjacent joint disease at hip joint was induced by adult spinal fusion surgery including sacroiliac joint fixation on an X-ray study. The mechanism is still unclear. We aimed to investigate the association between lumbosacral fusion including sacroiliac joint fixation and contact stress of the hip joint. Methods: A 40-year-old woman with intact lumbar vertebrae underwent computed tomography. A three-dimensional nonlinear finite element model was constructed from the L4 vertebra to the femoral bone with triangular shell elements (thickness, 2 mm; size, 3 mm) for the cortical bone's outer surface and 2-mm (lumbar spine) or 3-mm (femoral bone) tetrahedral solid elements for the remaining bone. We constructed the following four models: a non-fusion model (NF), a L4-5 fusion model (L5F), a L4-S1 fusion model (S1F), and a L4-S2 alar iliac screw fixation model (S2F). A compressive load of 400 N was applied vertically to the L4 vertebra and a 10-Nm bending moment was additionally applied to the L4 vertebra to stimulate flexion, extension, left lateral bending, and axial rotation. Each model's hip joint's von Mises stress and angular motion were analyzed. Results: The hip joint's angular motion in NF, L5F, S1F, and S2F gradually increased; the S2F model presented the greatest angular motion. Conclusions: The average and maximum contact stress of the hip joint was the highest in the S2F model. Thus, lumbosacral fusion surgery with sacroiliac joint fixation placed added stress on the hip joint. We propose that this was a consequence of adjacent joint spinopelvic fixation. Lumbar-to-pelvic fixation increases the angular motion and stress at the hip joint.

Sacroiliac Joint Pain Should Be Suspected in Early Buttock and Groin Pain after Adult Spinal Deformity Surgery: An Observational Study.

Introduction: Sacroiliac joint pain (SIJP) is one of the pathological conditions of adjacent segment disorders occurring after adult spinal deformity (ASD) surgery. This study aimed to test the hypothesis that even in ASD surgery using S2 alar-iliac (S2AI) screws, SIJP can develop much earlier than reported previously and can be rescued by ultrasound-guided sacroiliac joint block. Methods: Overall, 94 patients with ASD treated with long spinal fusion using S2AI screws were prospectively investigated for SIJP postoperatively, and the effect of ultrasound-guided sacroiliac joint block was evaluated. Additionally, the relationship between the symptomatic side of the SIJP and the surgical procedure; the preoperative and postoperative whole-spine sagittal and coronal alignment, lumbar pelvis sagittal plane alignment, and pelvic incidence-lumbar lordosis were retrospectively compared between the groups with and without SIJP. Results: Eleven of 94 cases (11.7%) developed SIJP. The average onset was 12.0 (±6.2) days after surgery. The "one-finger test," "Gaenslen test," and "tenderness of the posterosuperior iliac spine" had high positivity rates for SIJP. Night pain occurred in 81.8% of patients and was one of the diagnostic features. There were no significant relationships between the symptomatic side of SIJP and the approach-side of lumbar interbody fusion, donor site of the iliac bone graft, or malposition of the S2AI screw. There were no significant differences in preoperative characteristics and radiological parameters between the SIJP-positive and -negative groups preoperatively, postoperatively, or in postoperative changes. Two of the 11 cases required the SIJ block four times, but all patients eventually achieved >70% pain relief with no recurrence. Conclusions: For good pain control and physical therapy, the fact that early buttock-groin pain after spinal fusion surgery has a 12% likelihood of being due to SIJP and can be relieved with the ultrasound-guided SIJ block is clinically important for diagnosis and pain management.