Therapeutic Intervention for Osteoporosis of Surgical Cases With Non-Vertebral Fractures for Three Years in a Newly Established Rural Hospital in Japan.

Objectives Our hospital was newly opened in the spring of 2020 in a rural area of Japan, with a remarkably developing aging society and population decline. This study aimed to clarify and evaluate the practice of osteoporosis care in our hospital for three years since its establishment. We report a retrospective review of therapeutic interventions for osteoporosis for patients who underwent surgical treatment for non-vertebral fragility fractures in our hospital. Methods We evaluated the practice of osteoporosis intervention in patients who underwent surgery for proximal humerus fractures (PHFs), distal radius fractures (DRFs), or proximal femoral fractures (PFFs) from April 2020 to the end of March 2023. Results There were 115 surgical cases with non-vertebral fractures (10 patients with PHF, 41 patients with DRF, and 64 with PFF). Among the patients who had received osteoporosis treatment at other hospitals before the injury, only 15 (13.0%) patients had been administered therapeutic intervention for osteoporosis by other clinics or hospitals. Also, 82 (71.3%) patients were newly diagnosed with osteoporosis in our hospital after surgery according to the Japanese osteoporosis guideline. New postoperative osteoporosis interventions were administered to 39 (47.0%) patients, of which the rate was higher than the previous reports in Japan. While there was no significant difference between upper limb fracture and PFF in the percentage per young adult mean of spine areal bone marrow density (aBMD), the femoral neck aBMDs in the upper limb fracture group were significantly higher than in the PFF group. The serum total P1NP levels were significantly lower and the 25(OH)D levels were also greater in the upper limb fracture group than in the PFF group, whereas the serum TRACP-5b levels were not significantly different between the two groups. Two (1.7%) patients were affected with secondary fractures during the study period. Conclusions The rates of therapeutic intervention for osteoporosis of patients with non-vertebral fractures, especially in those with upper limb fractures, in our hospital were considered to be greater than those in the previous reports. However, the intervention rate for patients with PFFs was not much, and there was still room for improvement in our hospital concerning osteoporosis diagnosis and treatment.

Pelvic Incidence As a Predictor of Proximal Junctional Kyphosis in Patients with Lenke type 5 Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective comparative study. OBJECTIVE: To evaluate the relationship between pelvic incidence (PI) and proximal junctional kyphosis (PJK) in patients with Lenke type 5 adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Although PJK is a common complication of sagittal malalignment after posterior correction and fusion surgery (PSF), few studies have assessed its risk factors. The significance of pelvic morphology in relation to PJK has been suggested but remains unclear in Lenke type 5 AIS patients. METHODS: A total of 92 patients with Lenke type 5 AIS who underwent selective thoracolumbar PSF with a minimum follow-up of two years were included. Patients were divided into PJK and non-PJK groups based on postoperative radiographs. The influence of PI on PJK occurrence was evaluated through binary logistic analysis. Subgroup analysis was performed based on the PI value (low PI,<45°; high PI, ≥ 45°) to identify factors affecting PJK occurrence. RESULTS: PJK was observed in 17.4% of the whole cohort. Binary logistic regression analysis identified low PI and large TL/L curve as a risk factor for PJK (PI, odds ratio, 0.933; TL/L curve, odds ratio, 1.080). Subgroup analysis showed that the postoperative increase in the upper instrumented vertebra slope in PJK cases was comparable in both the low and high PI groups. Meanwhile, lordotic changes in the fused area in the PJK cases were observed only in the low PI group. No difference in the Scoliosis Research Society 22 scores were observed between the two groups. CONCLUSION: From this study a low PI was identified as a risk factor for the occurrence of PJK in Lenke type 5 AIS patients. The occurrence of PJK is influenced by lordotic changes in the fused area and the limited compensatory capacity of the pelvis in patients with a low PI.

Influence of slippage reduction and correction of lumbosacral kyphosis by single-level posterior lumbar interbody fusion on spinal alignment in patients with dysplastic spondylolisthesis.

PURPOSE: To investigate the influence of slippage reduction and correction of lumbosacral kyphosis by L5-S1 single-level posterior lumbar interbody fusion (PLIF) on spinal alignment and clinical outcomes including postoperative complications in patients with dysplastic spondylolisthesis (DS). METHODS: Twenty consecutive patients with symptomatic and severe DS who underwent L5-S1 single-level PLIF with a minimum of 2 years of follow-up after surgery were included. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores for low back and leg pain obtained on preoperative and postoperative examinations. Postoperative instrumentation failure and L5 radiculopathy were also evaluated. The preoperative and postoperative spinopelvic parameters were measured. RESULTS: The JOA score significantly improved from 21.5 ± 4.8 (preoperative) to 27.0 ± 2.5 (postoperative), with a mean recovery rate of 75.0% ± 30.4%. The VAS score for low back pain significantly improved from 44.5 ± 30.1 (preoperative) to 11.5 ± 15.9 (postoperative), and that for leg pain significantly improved from 31.0 ± 33.2 (preoperative) to 5.0 ± 10.2 (postoperative). The slip percentage (% slip) significantly improved from 59.6% ± 13.5% (preoperative) to 25.2% ± 15.0% (postoperative). The lumbosacral angle (LSA) significantly improved from 12.3° ± 9.5° (preoperative) to 1.0° ± 4.9° (postoperative). L5-S1 PLIF led to significant improvement of lumbar lordosis (from 52.0° ± 15.9° to 59.7° ± 8.0°) and pelvic incidence - lumbar lordosis mismatch (from 23.9° ± 20.6° to 13.3° ± 10.0°). Correction of lumbosacral kyphosis had a significant positive correlation with postoperative pelvic tilt (PT) (r = 0.50, P = 0.02), while postoperative % slip did not have a significant correlation with postoperative PT. CONCLUSIONS: L5-S1 PLIF for DS provided good clinical outcomes. Correction of lumbosacral kyphosis had a positive impact on regaining ideal spinopelvic balance and may be beneficial in the setting of treating DS.

Development and Validation of Machine Learning-Based Predictive Model for Prolonged Hospital Stay after Decompression Surgery for Lumbar Spinal Canal Stenosis.

Introduction: Precise prediction of hospital stay duration is essential for maximizing resource utilization during surgery. Existing lumbar spinal stenosis (LSS) surgery prediction models lack accuracy and generalizability. Machine learning can improve accuracy by considering preoperative factors. This study aimed to develop and validate a machine learning-based model for estimating hospital stay duration following decompression surgery for LSS. Methods: Data from 848 patients who underwent decompression surgery for LSS at three hospitals were examined. Twelve prediction models, using 79 preoperative variables, were developed for postoperative hospital stay estimation. The top five models were chosen. Fourteen models predicted prolonged hospital stay (≥14 days), and the most accurate model was chosen. Models were validated using a randomly divided training sample (70%) and testing cohort (30%). Results: The top five models showed moderate linear correlations (0.576-0.624) between predicted and measured values in the testing sample. The ensemble of these models had moderate prediction accuracy for final length of stay (linear correlation 0.626, absolute mean error 2.26 days, standard deviation 3.45 days). The c5.0 decision tree model was the top predictor for prolonged hospital stay, with accuracies of 89.63% (training) and 87.2% (testing). Key predictors for longer stay included JOABPEQ social life domain, facility, history of vertebral fracture, diagnosis, and Visual Analogue Scale (VAS) of low back pain. Conclusions: A machine learning-based model was developed to predict postoperative hospital stay after LSS decompression surgery, using data from multiple hospital settings. Numerical prediction of length of stay was not very accurate, although favorable prediction of prolonged stay was accomplished using preoperative factors. The JOABPEQ social life domain score was the most important predictor.

Safety and Efficacy of Tranexamic Acid in Spinal Surgery: A Systematic Review and Meta-Analysis.

Background: Tranexamic acid (TXA) has gained popularity in spinal surgery because of its potential to reduce blood loss. However, concerns regarding its safety and efficacy remain. This systematic review and meta-analysis aimed to evaluate the efficacy of TXA in reducing blood loss and its safety profile in spinal surgeries. Methods: A comprehensive search was conducted in electronic databases for randomized controlled trials and prospective studies evaluating the use of TXA in spinal surgery. The primary outcomes were intraoperative and total estimated blood loss (EBL), and the secondary outcomes included the incidence and types of complications associated with TXA use. Meta-analyses were performed using random-effects models. Results: Thirteen studies involving 1,213 participants were included in the meta-analysis. The use of TXA was associated with significant reductions in both intraoperative (mean difference: -46.56 mL [-73.85, -19.26], p<0.01]) and total EBL (mean difference: -210.17 mL [-284.93, -135.40], p<0.01) while also decreasing the need for blood transfusions (risk ratio: 0.68 [0.51, 0.90], p<0.01). No significant difference was found in the incidence and types of thrombotic complications when TXA was used in spinal surgery. Subgroup analysis showed consistent results in instrumentation and fusion surgery and different doses of TXA. Conclusions: TXA is effective in reducing intraoperative and overall blood loss in spinal surgery without increasing the risk of complications. These findings support the use of TXA to improve patient outcomes. However, caution should be exercised because of the heterogeneity among the included studies. Further research is needed to confirm these findings and explore potential long-term complications.

Dysregulation of Inflammatory Pathways in Adult Spinal Deformity Patients with Frailty.

Background/Objectives: An important aspect of the pathophysiology of frailty seems to be the dysregulation of inflammatory pathways and the coagulation system. However, an objective assessment of the impact of frailty on the recovery from surgery is not fully studied. This study sought to assess how frailty affects the recovery of adult spinal deformity (ASD) surgery using blood biomarkers. Methods: 153 consecutive ASD patients (age 64 ± 10 yr, 93% female) who had corrective spine surgery in a single institution and reached 2y f/u were included. The subjects were stratified by frailty using the modified frailty index-11 (robust [R] group or prefrail and frail [F] group). Results of commonly employed laboratory tests at baseline, 1, 3, 7, and 14 post-operative days (POD) were compared. Further comparison was performed in propensity-score matched-39 paired patients between the groups by age, curve type, and baseline alignment. A correlation between HRQOLs, major complications, and biomarkers was performed. Results: Among the propensity-score matched groups, CRP was significantly elevated in the F group at POD1,3(POD1; 5.3 ± 3.1 vs. 7.9 ± 4.7 p = 0.02, POD3; 6.6 ± 4.6 vs. 8.9 ± 5.2 p = 0.02). Transaminase was also elevated in the F group at POD3(ASD: 36 ± 15 vs. 51 ± 58 U/L, p = 0.03, ALT: 32 ± 16 vs. 47 ± 55 U/L, p = 0.04). Interestingly, moderate correlation was observed between transaminase at POD1 and 2 y SRS22 (AST; function r = -0.37, mental health r = -0.39, satisfaction -0.28, total r = -0.40, ALT; function r = -0.37, satisfaction -0.34, total r = -0.39). Conclusions: Frailty affected the serum CRP and transaminase differently following ASD surgery. Transaminase at early POD was correlated with 2 y HRQOLs. These findings support the hypothesis that there is a specific physiological basis to the frailty that is characterized in part by increased inflammation and that these physiological differences persist.

Satisfaction following correction of spinal deformity: Cultural and regional effects on outcome.

Corrective spine surgery for spinal deformities, such as adolescent idiopathic scoliosis (AIS) and adult spinal deformity (ASD), aims to enhance the quality of life by addressing physical impairments. However, the extent of patient satisfaction after surgery, which includes pain management, functional recovery, and psychological contentment, exhibits considerable variation across different cultural and geographical landscapes. This review describes the influence of cultural and regional disparities on postoperative satisfaction in AIS and ASD surgery with a particular emphasis on the disparities between the US and Japan. This review underscores the intricate relationship between surgical outcomes and patient-reported satisfaction metrics. The investigation reveals significant contrasts in patient satisfaction and clinical results between these 2 countries, attributed to divergent cultural expectations, lifestyle adaptations, and perceptions of bodily image. These distinctions are crucial for healthcare professionals to recognize, as they necessitate a culturally nuanced approach to patient care. This comparative review not only enhances the understanding of patient experiences across cultures but also provides valuable guidance for physicians in customizing their strategies to align with the varied expectations of their patients, thereby improving postoperative satisfaction and overall quality of life. This review emphasizes the necessity of a tailored and culturally sensitive approach to managing spinal deformities, underscoring the need to factor in cultural and regional elements to enhance patient satisfaction and surgical outcomes.

Factors Associated with the Maintenance of Cost-Effectiveness at 5 Years in Adult Spinal Deformity Corrective Surgery.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To evaluate factors associated with the long-term durability of cost-effectiveness (CE) in ASD patients. BACKGROUND: A substantial increase in costs associated with the surgical treatment for adult spinal deformity (ASD) has given precedence to scrutinize the value and utility it provides. METHODS: We included 327 operative ASD patients with 5-year (5 Y) follow-up. Published methods were used to determine costs based on CMS.gov definitions and were based on the average DRG reimbursement rates. Utility was calculated using quality-adjusted life-years (QALY) utilizing the Oswestry Disability Index (ODI) converted to Short-Form Six-Dimension (SF-6D), with a 3% discount applied for its decline with life expectancy. The CE threshold of $150,000 was used for primary analysis. RESULTS: Major and minor complication rates were 11% and 47% respectively, with 26% undergoing reoperation by 5 Y. The mean cost associated with surgery was $91,095±$47,003, with a utility gain of 0.091±0.086 at 1Y, QALY gained at 2 Y of 0.171±0.183, and at 5 Y of 0.42±0.43. The cost per QALY at 2 Y was $414,885, which decreased to $142,058 at 5 Y.With the threshold of $150,000 for CE, 19% met CE at 2 Y and 56% at 5 Y. In those in which revision was avoided, 87% met cumulative CE till life expectancy. Controlling analysis depicted higher baseline CCI and pelvic tilt (PT) to be the strongest predictors for not maintaining durable CE to 5 Y (CCI OR: 1.821 [1.159-2.862], P=0.009) (PT OR: 1.079 [1.007-1.155], P=0.030). CONCLUSIONS: Most patients achieved cost-effectiveness after four years postoperatively, with 56% meeting at five years postoperatively. When revision was avoided, 87% of patients met cumulative cost-effectiveness till life expectancy. Mechanical complications were predictive of failure to achieve cost-effectiveness at 2 Y, while comorbidity burden and medical complications were at 5 Y.

Predictors of pelvic tilt normalization: a multicenter study on the impact of regional and lower-extremity compensation on pelvic alignment after complex adult spinal deformity surgery.

OBJECTIVE: The objective was to determine the degree of regional decompensation to pelvic tilt (PT) normalization after complex adult spinal deformity (ASD) surgery. METHODS: Operative ASD patients with 1 year of PT measurements were included. Patients with normalized PT at baseline were excluded. Predicted PT was compared to actual PT, tested for change from baseline, and then compared against age-adjusted, Scoliosis Research Society-Schwab, and global alignment and proportion (GAP) scores. Lower-extremity (LE) parameters included the cranial-hip-sacrum angle, cranial-knee-sacrum angle, and cranial-ankle-sacrum angle. LE compensation was set as the 1-year upper tertile compared with intraoperative baseline. Univariate analyses were used to compare normalized and nonnormalized data against alignment outcomes. Multivariable logistic regression analyses were used to develop a model consisting of significant predictors for normalization related to regional compensation. RESULTS: In total, 156 patients met the inclusion criteria (mean ± SD age 64.6 ± 9.1 years, BMI 27.9 ± 5.6 kg/m2, Charlson Comorbidity Index 1.9 ± 1.6). Patients with normalized PT were more likely to have overcorrected pelvic incidence minus lumbar lordosis and sagittal vertical axis at 6 weeks (p < 0.05). GAP score at 6 weeks was greater for patients with nonnormalized PT (0.6 vs 1.3, p = 0.08). At baseline, 58.5% of patients had compensation in the thoracic and cervical regions. Postoperatively, compensation was maintained by 42% with no change after matching in age-adjusted or GAP score. The patients with nonnormalized PT had increased rates of thoracic and cervical compensation (p < 0.05). Compensation in thoracic kyphosis differed between patients with normalized PT at 6 weeks and those with normalized PT at 1 year (69% vs 35%, p < 0.05). Those who compensated had increased rates of implant complications by 1 year (OR [95% CI] 2.08 [1.32-6.56], p < 0.05). Cervical compensation was maintained at 6 weeks and 1 year (56% vs 43%, p = 0.12), with no difference in implant complications (OR 1.31 [95% CI -2.34 to 1.03], p = 0.09). For the lower extremities at baseline, 61% were compensating. Matching age-adjusted alignment did not eliminate compensation at any joint (all p > 0.05). Patients with nonnormalized PT had higher rates of LE compensation across joints (all p < 0.01). Overall, patients with normalized PT at 1 year had the greatest odds of resolving LE compensation (OR 9.6, p < 0.001). Patients with normalized PT at 1 year had lower rates of implant failure (8.9% vs 19.5%, p < 0.05), rod breakage (1.3% vs 13.8%, p < 0.05), and pseudarthrosis (0% vs 4.6%, p < 0.05) compared with patients with nonnormalized PT. The complication rate was significantly lower for patients with normalized PT at 1 year (56.7% vs 66.1%, p = 0.02), despite comparable health-related quality of life scores. CONCLUSIONS: Patients with PT normalization had greater rates of resolution in thoracic and LE compensation, leading to lower rates of complications by 1 year. Thus, consideration of both the lower extremities and thoracic regions in surgical planning is vital to preventing adverse outcomes and maintaining pelvic alignment.

How coronal malalignment affects the surgical outcome in corrective spine surgery for adult symptomatic lumbar deformity.

PURPOSE: The importance of coronal alignment is unclear, while the importance of sagittal alignment in the treatment of adult patients with spinal deformities is well described. This study sought to elucidate the impact of global coronal malalignment (GCMA) in surgically treated adult symptomatic lumbar deformity (ASLD) patients. METHODS: A multicentre retrospective analysis of a prospective ASD database. GCMA was defined as GCA (C7PL-CSVL) ≥ 3 cm. GCMA is categorized based on the Obeid-Coronal Malalignment Classification (O-CM). Demographic, surgical, radiographic, HRQOL, and complication data were analysed. The risk for postoperative GCMA was analysed by univariate and multivariate analyses. RESULTS: Of 230 surgically treated ASLD patients, 96 patients showed GCMA preoperatively and baseline GCA was correlated with the baseline SRS-22 pain domain score (r = - 30). Postoperatively, 62 patients (27%, O-CM type 1: 41[18%], type 2: 21[9%]) developed GCMA. The multivariate risk analysis indicated dementia (OR 20.1[1.2-304.4]), diabetes (OR 5.9[1.3-27.3]), and baseline O-CM type 2 (OR 2.1[1.3-3.4]) as independent risk factors for postoperative GCMA. The 2-year SRS-22 score was not different between the 2 groups, while 4 GCMA patients required revision surgery within 1 year after surgery due to coronal decompensation (GCMA+ vs. GCMA- function: 3.6 ± 0.6 vs. 3.7 ± 0.7, pain: 3.7 ± 0.8 vs. 3.8 ± 0.8, self-image: 3.6 ± 0.8 vs. 3.6 ± 0.8, mental health: 3.7 ± 0.8 vs. 3.8 ± 0.9, satisfaction: 3.9 ± 0.9 vs. 3.9 ± 0.8, total: 3.7 ± 0.7 vs. 3.7 ± 0.7). Additionally, the comparisons of 2-yr SRS-22 between GCMA ± showed no difference in any UIV and LIV level or O-CM type. CONCLUSIONS: In ASLD patients with corrective spine surgery, GCMA at 2 years did not affect HRQOL or major complications at any spinal fusion extent or O-CM type of malalignment, whereas GCA correlated with pain intensity before surgery. These findings may warrant further study of the impact of GCMA on HRQOL in the surgical treatment of ASLD patients.

Adolescent Idiopathic Scoliosis: Is the Feasible Option of Minimally Invasive Surgery using Posterior Approach?

The purpose of this systematic review and meta-analysis is to perform a systematic review and meta-analysis of previous studies on minimally invasive scoliosis surgery (MISS) in adolescents with idiopathic scoliosis (AIS). Some data on MISS in AIS compared with conventional open scoliosis surgery (COSS) are conflicting. A systematic literature search was conducted in Medline, Embase, and Cochrane Library, including studies reporting outcomes for MISS in AIS. The meta-analysis compared the operative, radiological, and clinical outcomes and complications between MISS and COSS in patients with AIS. Of the 208 records identified, 15 nonrandomized studies with 1,369 patients (reviews and case reports are excluded) were included in this systematic review and meta-analysis. The mean scale was 6.1, and eight of the 15 included studies showed satisfactory quality using the Newcastle-Ottawa scale. For operative outcomes, MISS had significant benefits in terms of estimated blood loss (standard mean difference [SMD], -1.87; 95% confidence interval [CI], -2.94 to -0.91) and hospitalization days (SMD, -2.99; 95% CI, -4.45 to -1.53) compared with COSS. However, COSS showed significantly favorable outcomes for operative times (SMD, 1.71; 95% CI, 0.92-2.51). No significant differences were observed in radiological outcomes, including Cobb's angle of the main curve and thoracic kyphosis. For clinical outcomes, MISS showed significant benefits on the visual analog scale score (SMD, -0.91; 95% CI, -1.36 to -0.47). The overall complication rates of MISS were similar to those of COSS (SMD, 0.96; 95% CI, 0.61-1.52). MISS using the posterior approach provides equivalent radiological and clinical outcomes and complication rates compared with COSS. Considering the lower estimated blood loss, shorter hospitalization days, and longer operative times in MISS, COSS is still the mainstay of surgical treatment in AIS; however, MISS using the posterior approach is also one of the surgical options of choice in the case of moderate AIS.

Proximal Junctional Failure in Adult Spinal Deformity Surgery: An In-depth Review.

Adult spinal deformity (ASD) surgery aims to correct abnormal spinal curvature in adults, leading to improved functionality and reduced pain. However, this surgery is associated with various complications, one of which is proximal junctional failure (PJF). PJF can have a significant impact on a patient's quality of life, necessitating a comprehensive understanding of its causes and the development of effective management strategies. This review aims to provide an in-depth understanding of PJF in ASD surgery. PJF is a complex complication resulting from a multitude of factors including patient characteristics, surgical techniques, and postoperative management. Age, osteoporosis, overcorrection of sagittal alignment, and poor bone quality are identified as significant risk factors. The clinical implications of PJF are substantial, often requiring revision surgery and causing a considerable decrease in patients' quality of life. Prevention strategies include careful preoperative planning, appropriate patient selection, and optimization of surgical techniques. Treatment often necessitates a multifaceted approach, including surgical intervention and the management of underlying risk factors. Predictive modeling is an emerging field that may offer a promising avenue for the risk stratification of patients and individualized preventive strategies. A thorough understanding of PJF's pathogenesis, risk factors, and clinical implications is essential for surgeons involved in ASD surgery. Current preventive measures and treatment strategies aim to mitigate the risk and manage the complications of PJF, but the complication cannot be entirely prevented. Future research should focus on the development of more effective preventive and treatment strategies, and predictive models could be valuable in this pursuit.

The Effect of Age-adjusted Sagittal Alignment on the Result of Posterior Decompression Surgery for Lumbar Spinal Canal Stenosis.

STUDY DESIGN: Retrospective case series. OBJECTIVE: The aim of this study was to compare the outcomes of posterior decompression surgery for lumbar spinal canal stenosis (LSS) in patients with preoperative sagittal malalignment to those without, after adjusting for age and sex. SUMMARY OF BACKGROUND DATA: Sagittal balance is an important factor in spine surgery and is thought to affect postoperative outcomes following LSS. However, the relationship between sagittal malalignment and postoperative outcomes has not been thoroughly examined. METHODS: We included 533 patients who underwent surgical treatment for LSS and also achieved two-year follow-up. Patients were categorized into either a malalignment (MA+) group (69 patients) or a matched-alignment (MA-) group (348 patients) based on age-adjusted preoperative sagittal alignment. We compared the baseline and two-year postoperative health-related quality of life (HRQOL) using the Visual Analog Scale and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) scores. We also calculated clinical efficacy using the minimal clinically important difference (MCID) based on JOABPEQ scores, and age- and sex-adjusted JOABPEQ scores two years after surgery. Differences between groups were examined using the Mann‒Whitney U test and χ 2 analysis, where applicable. RESULTS: Both groups showed an improved HRQOL after decompression surgery. Similar proportions of patients showed substantial improvement, as estimated by the MCID, in four out of five subdomains of the JOABPEQ. A significantly smaller proportion of patients in the MA+ group showed substantial improvement in lumbar function. The age- and sex-adjusted HRQOL scores two years after surgery were lower in the MA+ group, particularly in the lumbar function and social life function subdomains of the JOABPEQ. CONCLUSION: The effects of posterior decompression surgery alone can still be observed at least two years postoperatively for patients with LSS and concomitant sagittal malalignment. Patients with sagittal malalignment may experience lower HRQOL than those without this type of malalignment.

Analysis of the sacroiliac joint vacuum phenomenon in adolescent thoracic idiopathic scoliosis (Lenke types 1 and 2).

The sacroiliac joint (SIJ) is the largest axial joint in the human body, and the SIJ vacuum phenomenon (SIJ VP) is a common finding in computed tomography studies of the abdomen, pelvis, and lumbosacral spine in adults, with the incidence increasing with age. Adolescent idiopathic scoliosis (AIS) is an abnormal spinal curvature that appears during adolescence and places abnormal stress on the SIJs. This retrospective observational study aimed to investigate the incidence of the SIJ VP in thoracic AIS (Lenke types 1 and 2). Sixty-seven patients with AIS (age: 12-19 years) and 76 controls (age: 11-19 years) were retrospectively analyzed to investigate SIJ VP, subchondral bone cysts, and SIJ degeneration (Eno classification: type 0, no degenerative change; type 1, mild degenerative changes; type 2, substantial degenerative changes; and type 3, ankylosis). SIJ degeneration was defined as type ≥ 2. The association between SIJ VP, cysts, SIJ degeneration, and sagittal/coronal spinopelvic alignment was assessed. SIJ VP (59% vs. 35.5%, P < .01), cysts (32.8% vs. 1.3%, P < .01), and SIJ degeneration (3.2% vs. 2.6%, P = .823) differed significantly between the 2 groups. There were 0 cases of SIJ ankylosis (Eno classification type 3) in both groups. The VP was not correlated with lumbar lordosis, sacral slope, or Cobb angle. All lumbar modifier type C belonged to the VP present group, whereas none to VP absent group. Our results suggest an association between AIS and SIJ VP and SIJ cysts. SIJ VP and SIJ cysts in AIS may be caused and accelerated by abnormal mechanical stress on SIJ due to spinal deformity.

Radiographical Results of Adolescent Idiopathic Scoliosis with Major Curve at Proximal Thoracic Spine.

Introduction: Adolescent idiopathic scoliosis (AIS) with a major curve at the main thoracic (MT) area is classified as Lenke type 1, 2, or 3 depending on the flexibility of the proximal thoracic (PT) curve and lumbar curve. No definite classification has been established for a major curve at the PT spine. The purpose of this study is to investigate the radiographic characteristics before and after correction surgery for AIS with a major curve at the PT area. Methods: This is a retrospective cohort study at a single academic institution. Twelve patients with a major curve at the PT spine participated in our study and followed for at least two years after surgery. We evaluated the pre- and postoperative Cobb angles of the curve, curve range, location of the apex, sagittal parameters, and shoulder balance-related parameters. All patients were treated by posterior correction and fusion surgery using pedicle screw constructs. Results: The patients were classified as having a double-curve (DC) type, in which the MT curve was structural, or a single-curve (SC) type, in which the MT curve was corrected to less than 25° on supine side-bending films. The mean correction rates for the PT curve were favorable in both groups (DC, 65.7%±9.6%; SC, 39.2%±4.9%). The mean Cobb angle of the lumbar curve improved in the DC group (preoperative, 17.1°±4.0°; postoperative, 5.0°±4.2°) but deteriorated in the SC group (preoperative, 7.1°±1.2°; postoperative, 12.4°±4.4°) after surgery. Conclusions: We illustrated the postoperative radiographical changes of 12 consecutive patients with the major curve at the PT curve. Although posterior correction and fusion surgery corrected the PT curve satisfactorily in both DC and SC patients, the Cobb angle of the lumbar curve deteriorated after surgery in all SC patients. Surgeons need to pay attention to the fusion area, especially LIV, when operating the SC curve type.

Clinical Features of Recurrent Spinal Cord Tumors.

Introduction: Only a few reports have described the clinical features of recurrent spinal cord tumors. This study aimed to report the recurrence rates (RRs), radiographic imaging, and pathological features of various histopathological recurrent spinal cord tumors using a large sample size. Methods: This study adopted the retrospective observational study design using a single-center study setting. We retrospectively reviewed 818 consecutive individuals operated for spinal cord and cauda equina tumors between 2009 and 2018 in a university hospital. We first determined the number of surgeries and then the histopathology, duration to reoperation, number of surgeries, location, degree of tumor resection, and tumor configuration of the recurrent cases. Results: A total of 99 patients (46 men and 53 women) who underwent multiple surgeries were identified. The mean duration between the primary and second surgeries was 94.8 months. A total of 74 patients underwent surgery twice, 18 patients thrice, and 7 patients 4 or more times. The recurrence sites were broadly distributed over the spine, with mainly intramedullary (47.5%) and dumbbell-shaped (31.3%) tumors. The RRs for each histopathology were as follows: schwannoma, 6.8%; meningioma and ependymoma, 15.9%; hemangioblastoma, 15.8%; and astrocytoma, 38.9%. The RRs after total resection were significantly lower (4.4%) than that after partial resection. Neurofibromatosis-associated schwannomas had a higher RR than sporadic schwannomas (p<0.001, odds ratio [OR]=8.54, 95% confidence interval [95% CI]: 3.67-19.93). Among the meningiomas, the RR increased to 43.5% in ventral cases (p<0.001, OR=14.36, 95% CI: 3.66-55.29). Within the ependymomas, partial resection (p<0.001, OR=2.871, 95% CI: 1.37-6.03) was found to be significantly correlated with recurrence. Dumbbell-shaped schwannomas exhibited a higher RR than non-dumbbell-shaped ones. Furthermore, dumbbell-shaped tumors other than schwannoma had a higher RR than dumbbell-shaped schwannomas (p<0.001, OR=16.0, 95% CI: 5.518-46.191). Conclusions: Aiming for total resection is essential to prevent recurrence. Dumbbell-shaped schwannomas and ventral meningiomas exhibited higher RR requiring revision surgery. As for dumbbell-shaped tumors, spinal surgeons should pay attention to the possibilities of non-schwannoma histopathologies.

Nationwide Survey of the Surgical Complications Associated with Lateral Lumbar Interbody Fusion in 2015-2020.

Introduction: Lateral lumbar interbody fusion (LLIF) has been introduced in Japan in 2013. Despite the effectiveness of this procedure, several considerable complications have been reported. This study reported the results of a nationwide survey performed by the Japanese Society for Spine Surgery and Related Research (JSSR) on the complications associated with LLIF performed in Japan. Methods: JSSR members conducted a web-based survey following LLIF between 2015 and 2020. Any complications meeting the following criteria were included: (1) major vessel, (2) urinary tract, (3) renal, (4) visceral organ, (5) lung, (6) vertebral, (7) nerve, and (8) anterior longitudinal ligament injury; (9) weakness of psoas; (10) motor and (11) sensory deficit; (12) surgical site infection; and (13) other complications. The complications were analyzed in all LLIF patients, and the differences in incidence and type of complications between the transpsoas (TP) and prepsoas (PP) approaches were compared. Results: Among the 13,245 LLIF patients (TP 6,198 patients [47%] and PP 7,047 patients [53%]), 389 complications occurred in 366 (2.76%) patients. The most common complication was sensory deficit (0.5%), followed by motor deficit (0.43%) and weakness of psoas muscle (0.22%). Among the patient cohort, 100 patients (0.74%) required revision surgery during the survey period. Almost half of the complications developed in patients with spinal deformity (183 patients [47.0%]). Four patients (0.03%) died from complications. Statistically more frequent complications occurred in the TP approach than in the PP approach (TP vs. PP, 220 patients [3.55%] vs. 169 patients [2.40%]; p<0.001). Conclusions: The overall complication rate was 2.76%, and 0.74% of the patients required revision surgery because of complications. Four patients died from complications. LLIF may be beneficial for degenerative lumbar conditions with acceptable complications; however, the indication for spinal deformity should be carefully determined by the experience of the surgeon and the extent of the deformity.

Natural history and surgical outcomes of idiopathic spinal cord herniation.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVES: Although surgery is frequently selected for the treatment of idiopathic spinal cord herniation (ISCH), its impact on functional outcomes has yet to be fully understood given the limited number of patients in previous studies. This study aims to evaluate the symptomatic history and surgical outcomes of ISCH. SETTING: Three institutions in Japan. METHODS: A total of 34 subjects with ISCH were retrospectively enrolled and followed up for at least 2 years. Demographic information, imaging findings, and clinical outcomes were collected. Functional status was assessed using the JOA score. RESULTS: The types of neurologic deficit were monoparesis, Brown-Sequard, and paraparesis in 5, 17, and 12 cases, with their mean disease duration being 1.2, 4.2, and 5.8 years, respectively. Significant differences in disease duration were observed between the monoparesis and Brown-Sequard groups (p < 0.01) and between the monoparesis and paraparesis groups (p = 0.04). Surgery promoted significantly better recovery rates from baseline. Correlations were observed between age at surgery and recovery rate (p < 0.01) and between disease duration and recovery rate (p = 0.04). The mean recovery rates were 82.6%, 51.6%, and 29.1% in the monoparesis, Brown-Sequard, and paraparesis groups, respectively. The monoparesis group had a significantly higher recovery rate than did the Brown-Sequard (p = 0.045) and paraparesis groups (p < 0.01). CONCLUSIONS: Longer disease duration was correlated with the progression of neurologic deficit. Older age, and worse preoperative neurologic status hindered postoperative functional recovery. These results highlight the need to consider surgical timing before neurologic symptoms deteriorate.

Resection of Cervical Dumbbell-Shaped Schwannoma Using Posterior Unilateral Approach: Impact on Postoperative Cervical Function and Clinical Outcomes.

STUDY DESIGN: A retrospective comparative study. OBJECTIVES: This study aimed to evaluate the radiographical changes in cervical sagittal alignment (CSA) and clinical outcomes after tumor resection using a posterior unilateral approach without spinal fixation for patients with cervical dumbbell-shaped schwannoma (DS). METHODS: Seventy-three patients with DS who were followed up for at least 2 years were included. The Eden classification was used to designate the types of DS. The CSA and range of motion (ROM) were analyzed using radiographs. The clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) score and JOA cervical myelopathy questionnaire. RESULTS: The CSA in the neutral, flexion, and extension position and cervical ROM were not significantly reduced in the follow-up period. The JOA scores showed significant improvement after surgery. The postoperative radiographic parameters and clinical outcomes of Eden type II or III DS, which needed facetectomy for the resection, did not show any statistically significant difference compared with those of Eden type I tumor, which was resected without facetectomy. Fifty-two cases (71.2%) achieved gross total resection, whereas 21 cases (28.8%) remained in partial resection (PR). One case underwent reoperation due to the regrowth of the remnant tumor whose margin was at the entrance of the intervertebral foramen. CONCLUSIONS: Tumor resection using the posterior unilateral approach preserved CSA and resulted in favorable clinical outcomes in patients with DS. When the resection ends in PR, the proximal margin of the remnant tumor should be located distally away from the entrance of the foramen to prevent regrowth.