Importance of physiological age in determining indications for adult spinal deformity surgery in patients over 75 years of age: a propensity score matching analysis.

PURPOSE: Physiologically, people age at different rates, which leads to a discrepancy between physiological and chronological age. Physiological age should be a priority when considering the indications for adult spinal deformity (ASD) surgery. The primary objective of this study was to determine the characteristics of the postoperative course, surgical outcomes, and complication rates to extend the healthy life expectancy of older ASD patients (≥ 75 years). The secondary objective was to clarify the importance of physiological age in the surgical treatment of older ASD patients, considering frailty. METHODS: A retrospective review of 109 consecutive patients aged ≥ 65 years with symptomatic ASD who underwent a corrective long fusion with lateral interbody fusion from the lower thoracic spine to the pelvis from 2015 to 2019 was conducted. Patients were classified into two groups according to age (group Y [65-74 years], group O [≥ 75 years]) and further divided into four groups according to the ASD-frailty index score (Y-F, Y-NF, O-F, and O-NF groups). To account for potential risk factors for perioperative course characteristics, complication rates, and surgical outcomes, patients from the database were subjected to propensity score matching based on sex, BMI, and preoperative sagittal spinal alignment (C7 sagittal vertical axis, pelvic incidence-lumbar lordosis, and pelvic tilt). Clinical outcomes were evaluated 2 years postoperatively, using three patient-reported outcome measures of health-related quality of life: the Oswestry Disability Index, Scoliosis Research Society questionnaire (SRS-22), and Short Form 36 (SF-36). Additionally, the postoperative time-to-first ambulation, as well as minor, major, and mechanical complications, were evaluated. RESULTS: In the comparison between Y and O groups, patients in group O were at a higher risk of minor complications (delirium and urinary tract infection). In contrast, other surgical outcomes of group O were comparable to those of group Y, except for SRS-22 (satisfaction) and time to ambulation after surgery, with better outcomes in Group O. Patients in the O-NF group had better postoperative outcomes (time to ambulation after surgery, SRS-22 (function, self-image, satisfaction), SF-36 [PCS]) than those in the Y-F group. CONCLUSIONS: Older age warrants monitoring of minor complications in the postoperative management of patients. However, the outcomes of ASD surgery depended more on frailty than on chronological age. Older ASD patients without frailty might tolerate corrective surgery and have satisfactory outcomes when minimally invasive techniques are used. Physiological age is more important than chronological age when determining the indications for surgery in older patients with ASD.

Inhibition of KDM2/7 Promotes Notochordal Differentiation of hiPSCs.

Intervertebral disc disease (IDD) is a debilitating spine condition that can be caused by intervertebral disc (IVD) damage which progresses towards IVD degeneration and dysfunction. Recently, human pluripotent stem cells (hPSCs) were recognized as a valuable resource for cell-based regenerative medicine in skeletal diseases. Therefore, adult somatic cells reprogrammed into human induced pluripotent stem cells (hiPSCs) represent an attractive cell source for the derivation of notochordal-like cells (NCs) as a first step towards the development of a regenerative therapy for IDD. Utilizing a differentiation method involving treatment with a four-factor cocktail targeting the BMP, FGF, retinoic acid, and Wnt signaling pathways, we differentiate CRISPR/Cas9-generated mCherry-reporter knock-in hiPSCs into notochordal-like cells. Comprehensive analysis of transcriptomic changes throughout the differentiation process identified regulation of histone methylation as a pivotal driver facilitating the differentiation of hiPSCs into notochordal-like cells. We further provide evidence that specific inhibition of histone demethylases KDM2A and KDM7A/B enhanced the lineage commitment of hiPSCs towards notochordal-like cells. Our results suggest that inhibition of KDMs could be leveraged to alter the epigenetic landscape of hiPSCs to control notochord-specific gene expression. Thus, our study highlights the importance of epigenetic regulators in stem cell-based regenerative approaches for the treatment of disc degeneration.

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.

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.

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.

Clinical risk factors associated with the development of adjacent segment disease in patients undergoing ACDF: A systematic review.

BACKGROUND CONTEXT: Cervical fusion for degenerative disorders carries a known risk of adjacent segment disease (ASD), a complication that often requires surgical intervention to relieve symptoms. Proposed risk factors for development of ASD include both clinical and radiographic patient characteristics. However, the true impact of these risk factors is less understood due to limitations in sample sizes and loss to follow-up in individual studies. PURPOSE: To review and critically examine current literature on the clinical risk factors associated with development of ASD in the cervical spine following ACDF. STUDY DESIGN: Systematic Review and Meta-Analysis. METHODS: We systematically reviewed the literature in December 2019 according to the PRISMA guidelines. Methodological quality of included papers and quality of evidence were evaluated according to MINORS and GRADE framework. Meta-analysis was performed to compute the odds ratio(OR)with corresponding 95% confidence interval(CI)for dichotomous data, and mean difference(MD) with 95% CI for continuous variables. RESULTS: 6,850 records were obtained using database query. Title/abstract screening resulted in 19 articles for full review, from which 10 papers met the criteria for analysis. There were no significant differences in gender (OR 0.99, 95% CI 0.75-1.30), BMI (MD -0.09, 95% CI -0.46 to 0.29), smoking (OR 1.13, 95% CI 0.80-1.59), alcohol (OR 1.07, 95% CI 0.70-1.64), diabetes (OR 0.85, 95% CI 0.56-1.31), number of segments fused (OR 0.86, 95% CI 0.64-1.16), and preoperative JOA (MD -0.50, 95% CI -1.04 to 0.04). Age (MD 3.21, 95% CI 2.00-4.42), congenital/developmental stenosis (OR 1.94, 95% CI 1.06-3.56), preoperative NDI (MD 4.18, 95% CI 2.11 to 6.26), preoperative VAS (neck) (MD 0.54 95% CI 0.09-0.99), and preoperative VAS (arm) (MD 0.98, 95% CI 0.43-1.34) were found to be statistically significant risk factors. CONCLUSION: Patients with congenital stenosis, advanced age, and high preoperative NDI are at increased risk of developing ASD.

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.

Long-term Clinical Outcomes of Microendoscopic Laminotomy for Cervical Spondylotic Myelopathy: A 5-Year Follow-up Study Compared With Conventional Laminoplasty.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The objective of this study was to characterize the long-term clinical and radiographic results of articular segmental decompression surgery using endoscopy [cervical microendoscopic laminotomy (CMEL)] for cervical spondylotic myelopathy (CSM) and to compare outcomes to conventional expansive laminoplasty (ELAP). SUMMARY OF BACKGROUND DATA: The spinal cord compression in CSM consists of a pincer mechanism due to bulging disk and a hypertrophied ligamentum flavum. The long-term clinical benefits of segmental decompression surgery, which removes the dorsal compressive elements of articular segment in CSM patients, have not yet been elucidated. MATERIALS AND METHODS: Consecutive patients with CSM who required surgical treatment were enrolled. All enrolled patients (n=81) underwent CMEL or ELAP. All patients were followed postoperatively for >5 years. The preoperative and 5-year follow-up evaluation included neurological assessment [Japanese Orthopaedic Association (JOA) score], JOA recovery rates, axial neck pain (visual analog scale), and cervical sagittal alignment (C2-C7 subaxial cervical angle). RESULTS: Sixty-four patients (CMEL group: 33, ELAP group: 31) were included for analysis. The preoperative JOA score was 10.1 points in the CMEL group and 11.1 points in the ELAP group (P=0.15). The JOA recovery rates were similar, 58.6% in the CMEL group and 55.2% in the ELAP group (P=0.55). The axial neck pain in the CMEL group was significantly lower than that in the ELAP group (P<0.01). At 5-year follow-up, cervical alignment was more favorable in the CMEL group, with an average 2.9 degrees gain in lordosis [vs. 2.3 degrees loss of lordosis in the ELAP group (P<0.05)] and lower incidence of postoperative kyphosis. CONCLUSIONS: CMEL is a novel, less invasive, technique that allows for multilevel posterior cervical decompression for treatment of CSM. Our 5-year follow-up data demonstrates that patients after CMEL have similar neurological outcomes to conventional laminoplasty, with significantly less postoperative axial pain and improved subaxial cervical lordosis when compared with their traditional laminoplasty counterparts.

A bicortical pedicle screw in the caudad trajectory is the best option for the fixation of an osteoporotic vertebra: An in-vitro experimental study using synthetic lumbar osteoporotic bone models.

BACKGROUND: In pedicle screw fixation, the optimal depth and trajectory of insertion are controversial, and this might be because of the wide variations in specimens. The present study aimed to investigate the biomechanically optimal depth and trajectory of screw insertion using synthetic lumbar osteoporotic vertebrae. METHODS: A total of 27 synthetic osteoporotic lumbar vertebrae (L3) were used to ensure standard vertebral quality and shape. Pedicle screws having two different lengths (unicortical: to the center of the vertebra; bicortical: to the anterior cortex of the vertebra) were inserted in the following three different trajectories: 1) straight-forward (parallel to the superior endplate), 2) cephalad (toward the anterosuperior corner), and 3) caudad (toward the anteroinferior corner). Maximum insertional torque and pull-out strength were measured. FINDINGS: For the straight-forward, cephalad, and caudad trajectories, the maximum insertional torque (Ncm) values of unicortical screws were 144.4, 143.1, and 148.9, respectively, and those of bicortical screws were 205.5, 156.2, and 207.8, respectively. The maximum insertional torque values were significantly higher for bicortical screws than unicortical screws (p < 0.001). Additionally, regarding bicortical screws, the maximum insertional torque values were significantly lower for the cephalad trajectory than other trajectories (p = 0.002). The pull-out strength (N) values of bicortical screws for the straight-forward, cephalad, and caudad trajectories were 703.3, 783.9, and 981.3, respectively. The pull-out strength values were significantly lower for the straight-forward trajectory than other trajectories (p = 0.034). INTERPRETATION: A bicortical pedicle screw in the caudad trajectory might be the best option to improve fixation in an osteoporotic lumbar vertebra.

Prevalence of cervical anterior and posterior spondylolisthesis and its association with degenerative cervical myelopathy in a general population.

The purpose of this study was to examine the prevalence of cervical spondylolisthesis according to age and vertebral level and its association with degenerative cervical myelopathy (DCM). This study included 959 participants (319 men and 640 women; mean age, 66.4 years) in the Wakayama Spine Study from 2008 to 2010. The outcome measures were cervical spinal canal (CSC) diameter at C5 level on plain radiographs, the degree of cervical spondylosis using the Kellgren-Lawrence (KL) grade, cervical cord compression on sagittal T2-weighted magnetic resonance imaging, and physical signs related to DCM. The prevalence of cervical anterior and posterior spondylolisthesis was investigated in men and women by age. In addition, logistic regression analysis determined the association between CSC diameter, posterior spondylolisthesis, and clinical DCM after overall adjustment for age, sex, and body mass index. The prevalence of anterior spondylolisthesis was 6.0% in men and 6.3% in women, and that of posterior spondylolisthesis was 13.2% and 8.9%, respectively. In addition, posterior spondylolisthesis prevalence increased with age in both sexes. Logistic regression analysis revealed that developmental canal stenosis (≤13 mm) and cervical posterior spondylolisthesis are independent significant predictive factors for DCM. The prevalence of degenerative cervical posterior spondylolisthesis was increasing with age and more frequent in men than in women. Narrow canal and degenerative cervical posterior spondylolisthesis on X-ray may be useful in predicting or diagnosing DCM.

Early versus delayed kyphoplasty for thoracolumbar osteoporotic vertebral fractures: The effect of timing on clinical and radiographic outcomes and subsequent compression fractures.

OBJECTIVE: Osteoporotic vertebral body fractures (OVFs) represent a significant medical and socioeconomic burden. There is ongoing debate concerning the role of cement augmentation versus conservative management, but we are increasingly recognizing the longer-term effects of kyphotic vertebral alignment on functional outcomes, pain, and subsequent fracture rates. The purpose of this study was to determine the effect of timing of intervention with percutaneous balloon kyphoplasty (BKP) for OVF on clinical and radiographic outcomes. PATIENTS AND METHODS: 51 patients (mean age, 75.5 years) who underwent BKP for OVF were analyzed. Patients were divided into two groups based on timing of BKP: early (<4 weeks) or late (>4 weeks). Multiple factors were assessed preoperatively and throughout follow up and compared between groups using bivariate testing, including: focal kyphosis, subsequent vertebral fracture, and low back pain. RESULTS: This was a retrospective sub-group analysis. There were 32 patients in the early group and 19 patients in the late group. There was no significant difference in preoperative bone density between groups. Mean follow-up was 1.2 years. Local kyphosis at final follow-up was significantly greater in the late group (-28.4°) than in the early group (-9.5°; p < 0.001). There was no significant difference in local kyphosis between preoperative measurement and final follow-up in the early (p = 0.741) or late cohort (p = 0.794). Patients treated with early BKP demonstrated significantly better LBP scores (p < 0.05) and a lower rate of subsequent vertebral fracture (p < 0.05). CONCLUSION: BKP is able to prevent progressive collapse and kyphosis after OVF, but not effectively restore alignment, and as a result, patients who undergo early BKP (<4 weeks) demonstrate better alignment, better LBP scores, and reduced rates of subsequent fracture at an average of 1.2 years following treatment.