Objective: To investigate the incidence of postoperative neurological complications among patients who underwent spinal deformity surgery and to determine the significant risk factors for postoperative neurological complications. Methods: Six databases PubMed, Web of Science, Scopus, MEDLINE, Embase, and Cochrane Library have been searched to identify observational studies from inception until January 2025. Inclusion criteria were patients aged ≥10 years with postoperative neurological complications after spinal deformity surgery. Stata/MP18.0 was used to conduct the meta-analysis in this review. The summary incidence estimates, proportion with 95% confidence intervals (CIs) and weights were pooled by the random-effects restricted maximum likelihood model. Results: The search strategy identified 53 articles with 40,958 patients for final review. Overall incidence of postoperative neurological complications was 7% (95% CI, 5.0%–9.0%; p < 0.001; I2 = 98.34%) in which incidence estimates for patients with adult spinal deformity and underwent 3-column spinal osteotomies were 12% (95% CI, 9%–16%; p < 0.001; I2 = 93.17%) and 18% (95% CI, 8%–31%; p < 0.001; I2 = 94.68%) respectively. Preoperative neurological deficit was the risk factor with highest overall odds ratio (OR, 2.86; 95% CI, 1.85–4.41; p = 0.01; I2 = 76.20%), followed by the presence of kyphosis (OR, 1.13; 95% CI, 0.75–1.70; p = 0.02; I2 = 81.80%) and age at surgery (OR, 1.04; 95% CI, 1.01–1.08; p = 0.04; I2 = 68.80%). Conclusion Preoperative neurological deficit, the presence of kyphosis and age at surgery were significant risk factors for postoperative neurological complications. Therefore, comprehensive preoperative assessment and surgical planning are crucial to minimize the risk of developing postoperative neurological complications or the deterioration of pre-existing neurologic deficits.

Objective: This study aims to investigate the anatomical relationship among the nerve roots, intervertebral space, pedicles, and intradural rootlets of the cervical spine for improving operative outcomes and exploring neuroventral decompression approach in posterior endoscopic cervical discectomy (PECD). Methods: Cervical computed tomography myelography imaging data from January 2021 to May 2023 were collected, and the RadiAnt DICOM Viewer Software was employed to conduct multiplane reconstruction. The following parameters were recorded: width of nerve root (WN), nerve root-superior pedicle distance (NSPD), nerve root-inferior pedicle distance (NIPD), and the relationship between the intervertebral space and the nerve root (shoulder, anterior, and axillary). Additionally, the descending angles between the spinal cord and the ventral (VRA) and dorsal (DRA) rootlets were measured. Results: The WN showed a gradual increase from C4 to C7, with measurements notably larger in men compared to women. The NSPD decreased gradually from the C2–3 to the C5–6 levels. However, the NIPD showed an opposite level-related change, notably larger than the NSPD at the C4–5, C5–6, and C7–T1 levels. Furthermore, significant differences in NIPD were observed between different age groups and genders. The incidence of the anterior type exhibited a gradual decrease from the C2–3 to the C5–6 levels. Conversely, the axillary type exhibited an opposite level-related change. Additionally, the VRA and DRA decreased as the level descended, with measurements significantly larger in females. Conclusion A prediction of the positional relationship between the intervertebral space and the nerve root is essential for the direct neuroventral decompression in PECD to avoid damaging the neural structures. The axillary route of the nerve root offers a safer and more effective pathway for performing direct neuroventral decompression compared to the shoulder approach.

Objective: This study aimed to compare the clinical and comprehensive radiological outcomes of 3 types of endoscopic decompression surgery: unilateral biportal endoscopic lumbar decompression (UBELD), microendoscopic laminotomy (MEL), and percutaneous endoscopic lumbar decompression (PELD). Methods: Patients with single-level lumbar spinal stenosis without instability were included in this multicenter retrospective study. Visual analogue scale (VAS) scores for each extremity, VAS back pain, and Japanese Orthopaedic Association (JOA) scores at preoperative and postoperative 1st, 6th, and 12th months were used as clinical outcome measures. In order to compare the radiological results of the patients, bilateral superior articular distance (SAD), bilateral lateral recess height (LR height), bilateral lateral recess angle (LR angle), and cross-sectional spinal canal area values were measured. Results: Eighty patients in the UBELD group, 73 patients in the MEL group, and 62 patients in the PELD group were included in the study. There was a statistically significant improvement in VAS scores and JOA scores in all groups compared to the preoperative period. At the 12th month postoperatively, the highest lateral decompression values on the approach side were determined as MEL (SAD: 4.1 mm, LR angle: 38.8°, LR height: 4.0 mm), followed by UBELD (SAD: 3.6 mm, LR angle: 36.2°, LR height: 3.3 mm) and PELD (SAD: 3.0 mm, LR angle: 21.7°, LR height: 2.3 mm), respectively. For the contralateral side, the highest lateral recess decompression values were listed as UBELD > MEL > PELD. Conclusion Effective decompression can be performed using all endoscopic techniques in lumbar spinal stenosis. However lateral recess decompression values were found to be better in UBELD and MEL techniques, compared to PELD.

Objective: This study aimed to explore the correlation between balance function and core muscle activation in patients with adolescent idiopathic scoliosis (AIS), compared to healthy individuals. Methods: A total of 24 AIS patients and 25 healthy controls were recruited. The limits of stability (LOS) test were conducted to assess balance function, while surface electromyography was used to measure the activity of core muscles, including the internal oblique, external oblique, and multifidus. Diaphragm thickness was measured using ultrasound during different postural tasks. Center of pressure (COP) displacement and trunk inclination distance were also recorded during the LOS test. Results: AIS patients showed significantly greater activation of superficial core muscles, such as the internal and external oblique muscles, compared to the control group (p < 0.05). Diaphragm activation was lower in AIS patients during balance tasks (p < 0.01). Although no significant difference was observed in COP displacement between the groups, trunk inclination was significantly greater in the AIS group during certain tasks (p < 0.05). Conclusion These findings suggest distinct postural control patterns in AIS patients, highlighting the importance of targeted interventions to improve balance and core muscle function in this population.

Objective: Based on spinopelvic parameters and biomechanical principles, the pedicle-facet joint (PFJ) morphological characteristics of isthmic and degenerative spondylolisthesis were analyzed, and the mechanism of their onset and progression was discussed. Methods: This retrospective cross-sectional study included 194 patients with L5 spondylolysis or L5–S1 low-grade isthmic spondylolisthesis (IS group), 172 patients with L4–5 degenerative spondylolisthesis (DS group), and 366 patients with nonlumbar spondylolysis (NL group). The spinopelvic parameters and PFJ morphological parameters of the patients were measured, the differences in these parameters among and within the 3 groups were compared, and the correlations were analyzed. Results: Sacral slope (SS) and lumbar lordosis (LL) were the highest in the IS group, the second highest in the DS group, and the lowest in the NL group. Among the 3 groups, the L4 facet joint angle (FJA) was the largest in the IS group, the second largest in the NL group, and the smallest in the DS group. The L4 pedicle-facet joint angle (PFA) was the largest in the DS group, the second largest in the IS group, and the smallest in the NL group. Pearson correlation analysis showed that within each group, SS and LL were negatively correlated with FJA and positively correlated with PFA. Conclusion This study found a correlation between the PFJ morphological characteristics of patients with lumbar spondylolisthesis and spinopelvic parameters, suggesting that the morphological characteristics of PFJs may be caused by varying stresses under different spinopelvic morphologies.

Purpose: Postoperative ileus (POI) typically occurs after abdominal surgery but can also affect patients undergoing spinal surgery via the lateral retroperitoneal approach, such as oblique lumbar interbody fusion (OLIF). Therefore, this study aimed to investigate the incidence and risk factors associated with POI in OLIF. Methods: This retrospective study examined a cohort of 465 patients who underwent OLIF from 2015 to 2023. Patient demographics, comorbidities, pre- and postoperative laboratory test results, and perioperative status were assessed. General condition of patients was assessed using the modified frailty index-11 (mFI-11), prognostic nutrition index, and geriatric nutrition risk index. In OLIF, the size and location of the psoas muscle involved in retraction and its relationship with the vertebral body were also investigated. Results: POI occurred in 19 patients (4%). Lower mFI-11 was linked to a higher risk of POI. While psoas muscle size had no significant effect on the risk of POI, the anterior location of the psoas muscle relative to the vertebral body was associated with a higher occurrence of POI. Multivariate logistic regression analysis of POI identified mFI-11 as the most significant risk factor (p = 0.003). Conclusion This study demonstrated that frailty and nutritional status can influence the occurrence of POI after OLIF. Additionally, bowel manipulation associated with the location of psoas muscle and vertebral body was identified as a risk factor. Proper assessment and improvement in patient frailty and nutritional status before surgery can help predict and prevent the occurrence of postoperative POI.

Objective: The precise mechanisms driving intervertebral disc degeneration (IVDD) development remain unclear, but evidence suggests a significant involvement of gut microbiota (GM) and blood metabolites. We aimed to investigate the causal relationships between GM, IVDD, and blood metabolites using Mendelian randomization (MR) analysis. Methods: We utilized the summary statistics of GM from the MiBioGen consortium, 1400 blood metabolites from the genome-wide association studies (GWAS) Catalog, and IVDD data from the FinnGen repository, which are sourced from the largest GWAS conducted to date. Employing bidirectional MR analyses, we investigated the causal relationships between GM and IVDD. Additionally, we conducted 2 mediation analyses, 2-step MR and multivariable MR (MVMR), to identify potential mediating metabolites. Results: Five bacterial genera were causally associated with IVDD, while IVDD did not show a significant causal effect on GM. In the 2-step MR analysis, Eubacteriumfissicatenagroup, RuminococcaceaeUCG003, Lachnoclostridium, and Marvinbryantia genera, along with metabolites X-24949, Pimeloylcarnitine/3-methyladipoylcarnitine (C7-DC), X-24456, histidine, 2-methylserine, Phosphocholine, and N-delta-acetylornithine, were all significantly associated with IVDD (all p < 0.05). MVMR analysis revealed that the associations between Eubacteriumfissicatenagroup genus and IVDD were mediated by X-24949 (8.1%, p = 0.024); Lachnoclostridium genus and IVDD were mediated by histidine (18.1%, p = 0.013); and RuminococcaceaeUCG003 genus and IVDD were mediated by C7-DC (-7.5%, p = 0.041). Conclusion The present MR study offers evidence supporting the causal relationships between several specific GM taxa and IVDD, as well as identifying potential mediating metabolites.

Purpose: To identify factors associated with adjacent-level ossification development (ALOD) after anterior cervical discectomy and fusion (ACDF) and associated clinical outcomes. Methods: We retrospectively reviewed records of 140 adults who underwent primary ACDF for degenerative disc disease. We compared patients with and without ALOD after ACDF. Radiographic measurements and factors associated with ALOD were assessed preoperatively and at minimum 24-month follow-up. Clinical outcomes were incidence of clinical adjacent-segment pathologies (CASP), revision surgery, and patient-reported outcomes. Results: Factors associated with both cranial and caudal ALOD were short plate-to-disc distance (PDD), adjacent-segment kyphosis, hyperlordotic ACDF causing junctional segment kyphosis, and preoperative ossification of the anterior longitudinal ligament (OALL). Mean final adjacent-segment range of motion (ROM) was less in those with cranial ALOD (6.9° ± 2.8°) than in those without cranial ALOD (12° ± 4.2°) (p < 0.01). Mean final adjacent-segment ROM was also less in those with caudal ALOD (5.5° ± 2.4º) than in those without caudal ALOD (8.2º ± 3.7º) (p < 0.01). The incidence of CASP-required surgery was higher in those with caudal ALOD (p = 0.02) but no different in those with cranial ALOD (p = 0.69) compared with those without ALOD. Conclusion Factors associated with ALOD were a kyphotic segment adjacent to ACDF, hyperlordotic fusion, preoperative OALL, and short PDD. ALOD was associated with less segmental ROM and, for those with caudal but not cranial ALOD, higher incidence of revision surgery for CASP.

Objective: Our study aimed to compare the posterior interposition technique against the posterolateral transosseous technique in the same cadaver specimens. Methods: Computer and cadaver models of 2 fixation techniques were developed. The computer model was constructed to analyze bone volume removed during implant placement and the bony surface area available for fusion. The cadaver model included quasi-static multidirectional bending flexibility and dynamic fatigue loading. Relative motions between the sacrum and ilium were measured intact, after joint destabilization, after fixation with direct-posterior and posterolateral techniques, and after 18,500 cycles of fatigue loading. Relative positions between each implant and the sacrum and ilium were measured after fixation and fatigue loading to ascertain the quality of the bone-implant interface. The 2 techniques were randomized to the left and right sacroiliac joints of the same cadavers. Results: The posterior interposition technique removed less bone volume and facilitated a larger surface area available for bony fusion. Posterior interposition significantly reduced the nutation/counternutation motion of the sacroiliac joint (42% ± 8%) and reduced it more than the posterolateral transosseous technique (14% ± 4%). Upon fatigue loading, the posterior interposition implant maintained the bone-implant interface across all specimens, while the posterolateral transosseous implant migrated or subsided in 20%–50% of specimens. Conclusion Posterior interposition fixation of the sacroiliac joint reduces joint motion. The amount of fixation from the posterior technique is superior and more durable than the amount of fixation achieved by the posterolateral technique.