Study Design Retrospective Cohort Study. Objective To propose a new technique named “lateral mass gutter” and investigate its role in augmenting spinal canal cross-sectional area (SCA) during laminoplasty. Methods This study included 105 patients who received cervical laminoplasty from February 2021 to February 2024. Patients were allocated to the conventional (CON) group or the lateral mass (LM) group according to the guttering technique used intraoperatively. Propensity score matching with a caliper of 0.2 was utilized to reduce selection bias. Intergroup comparisons encompassed clinical outcomes (Visual Analog Scale (VAS) of neck pain, Japanese Orthopaedic Association (JOA) score), radiographic measurements (SCA, laminoplasty opening angle (LOA), hinge fractures, hinge fusion, C2-7 Cobb angle) and postoperative complications (cerebrospinal fluid leakage, incisional fat liquefaction, C5 nerve root palsy, axial neck pain, cervical spine instability). Results Following propensity score matching, baseline parameters were comparable between the CON and LM groups (37 patients per group, P > 0.05). Compared to the CON group, the LM group exhibited a significantly smaller LOA, a lower incidence of hinge fractures, a higher rate of hinge fusion, greater improvement in JOA and a larger expansion in the SCA (P < 0.05). No statistically significant differences were observed between the two groups regarding VAS of neck pain or postoperative complications (P > 0.05). Conclusion Compared to conventional guttering technique, lateral mass gutter significantly reduces hinge fracture, promotes hinge fusion, enhances spinal canal expansion and optimizes postoperative neurological recovery in posterior cervical laminoplasty.
ObjectiveTo evaluate whether preoperative testosterone replacement therapy (TRT) use is associated with increased risks of pseudarthrosis and reoperation following single-level anterior cervical discectomy and fusion (ACDF).MethodsThe TriNetX Research Network was queried to identify adult males aged 18 to 89 years who underwent single-level ACDF. Patients were separated into a TRT exposure group within 1 year before initial ACDF procedure as well as comparator cohort without TRT exposure that was matched 1:1 using propensity score matching based on age, race, and relevant medical comorbidities. Patients were followed longitudinally for 2 years from the index procedure to assess postoperative outcomes. The primary outcomes were pseudarthrosis and reoperation. Risk ratios and time-to-event hazard ratios were calculated along with 95% confidence intervals.ResultsAfter propensity score matching, 494 matched pairs reached balance across all baseline characteristics. Patients receiving TRT demonstrated a 70% increased risk of pseudarthrosis (RR 1.70, CI 1.20-2.39; HR 1.71 CI 1.19 - 2.46) compared to the non-TRT cohort. TRT use was not associated with an increased risk of reoperation (RR 0.92 CI 0.59-1.43; HR 0.87, CI 0.55-1.38) following ACDF.ConclusionsPreoperative testosterone replacement therapy was associated with increased risk of pseudarthrosis, but not reoperation following ACDF. These findings suggest that TRT may represent an important patient-specific risk marker in patients undergoing ACDF. Given the observational design and potential for residual confounding, these findings should not be interpreted as evidence of a causal effect.
Study DesignRetrospective study.ObjectivesTo develop and validate a computer-assisted model for planning screw trajectories to support modified cortical bone trajectory (MCBT), cortical bone trajectory (CBT), and pedicle screw (PS) techniques, based on iterative closest point (ICP) registration and weighted k-nearest neighbors (kNN) algorithms.MethodsCT data from 110 patients undergoing lumbar surgery were analyzed, comprising an internal set of 50 younger patients with normal bone density and an external set of 60 patients including younger and older individuals with or without bone loss. L4-L5 segments were reconstructed using Mimics 21.0. Two surgeons manually planned MCBT, CBT, and PS trajectories bilaterally in the internal set to serve as reference standards. A personalized computer-assisted screw planning model was developed using ICP registration and weighted kNN, where the template library consisted of manually generated screw plans. Accuracy was evaluated by comparing algorithm-generated screw trajectories against expert manually planned trajectories to calculate deviations in sagittal inclination (α), axial inclination (β), screw head, pedicle entry point, pedicle crossing point, and screw tip. Hounsfield unit (HU) values along screw trajectories were also measured.ResultsIn the external set (total of 720 screws: 240 PS, 240 CBT, 240 MCBT), deviations for CBT weresagittal inclination (α) 4.117 (2.028, 7.251)°, axial inclination (β) 3.714 (1.901, 6.316)°, screw head 3.382 (2.514, 4.803) mm, pedicle entry point 3.0 (1.999, 4.149) mm, pedicle crossing point 1.511 (1.008, 2.443) mm, screw tip 3.586 (2.465, 4.542) mm. Those for MCBT were 4.865 (2.126, 7.547)°, 3.801 (1.658, 6.147)°, 4.153 (3.14, 5.658) mm, 3.818 (2.43, 6.209) mm, 1.545 (1.061, 2.222) mm, 3.777 (2.768, 5.241) mm, respectively. Computational acceptance rates for PS were 97.06% (HU: 238.4±67.71) in younger normal bone group, 92.71% (173.6±53.83) in older normal bone group, and 97.37% (113.3±58.68) in older bone loss group. For CBT, rates were 100% (477.2±168.6 HU), 100% (338.5±125.8 HU), and 100% (178.1±99.75 HU), respectively. For MCBT, rates were 100% (475.8±131 HU), 98.96% (376.8±104.9 HU), and 97.37% (213.4±106 HU), respectively. MCBT and CBT achieved significantly higher HU values than PS (P < 0.05).ConclusionThe ICP registration and weighted kNN-based planning model demonstrates high computational acceptance rates and excels in planning cortical bone screw trajectories with low breach rates and high HU values.
Study DesignRetrospective analysis of a prospectively maintained multicenter cohort.ObjectivesTo identify clinical characteristics associated with clinically meaningful improvement in neuropathic pain and to evaluate its relationship with postoperative functional outcomes in patients with degenerative cervical myelopathy (DCM).MethodsAmong 816 patients with complete Neuropathic Pain Symptom Inventory (NPSI) data, 597 with baseline total NPSI scores ≥7 were included in the primary analysis because they were eligible to achieve the predefined minimal clinically important difference (MCID) of a 7-point reduction. Patients were classified as responders or non-responders according to MCID achievement at 2 years postoperatively. Clinical outcomes included the cervical Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS), Short Form-36 (SF-36), and JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ).ResultsOf the 597 patients, 323 (54.1%) achieved the NPSI MCID. Responders had significantly higher preoperative total NPSI scores than non-responders, whereas no significant differences were observed in baseline JOA, VAS, or SF-36 scores. Responders demonstrated greater improvement in upper-extremity pain and numbness and in the SF-36 mental component summary score. They also showed significantly higher effectiveness rates in the upper-extremity, lower-extremity, bladder, and quality-of-life domains of the JOACMEQ.ConclusionsClinically meaningful improvement in neuropathic pain after surgery for DCM was associated with broader postoperative recovery across pain-related, functional, mental health, and quality-of-life outcomes. Assessment of neuropathic pain may provide clinically relevant information complementary to conventional measures of neurological function.
Study DesignRetrospective Cohort.ObjectivesAccurate, midline artificial disc placement is crucial when performing cervical disc replacement (CDR). Although cervical spinous processes (SPs) are considered midline structures, clinical experience has often shown noticeable deviation at times. This study aims to quantitatively characterize this known observation to better understand the utility of SPs as midline indicators during CDR.MethodsPatients who underwent anterior cervical discectomy and fusion with preoperative cervical spine computerized tomography (CT) scans were retrospectively identified, excluding those with previously surgically altered spines. Angular and lateral SP deviations from C3-C7 were collected from these CTs. Statistical analysis was conducted using one-way ANOVA with post-hoc testing using Tukey's test.ResultsThe average angular SP deviations at C3-C7 were 2.94 ± 2.06 degrees, 3.52 ± 2.19 degrees, 3.50 ± 2.13 degrees, 4.31 ± 2.15 degrees, and 3.53 ± 2.86 degrees, respectively. The average lateral SP deviations at C3-C7 relative to vertebral body widths were 5.43%, 6.10%, 6.14%, 8.17%, and 7.52%, respectively. Angular deviation at C6 was greater than C3 (p = 0.009). Relative lateral deviation at C6 was greater than at C3 (p = 0.027). Neither angular nor lateral deviation differed by sex at any level (p > 0.05 for all).ConclusionsGiven significant variation in cervical SP deviation between patients and by level, surgeons should hesitate to solely rely on them for determining vertebral midline during CDR. The C6 and C7 SPs especially should be used cautiously as they show relatively higher magnitudes and variations of deviation. However, the C3-C5 SPs may be of use if viewed in conjunction with other radiographic landmarks, such as the uncinate processes or medial borders of the pedicles.
Study DesignScoping review.ObjectiveTo systematically map and characterize the literature on the use of polymethyl methacrylate (PMMA) cement as an interbody spacer in the surgical management of pyogenic spondylodiscitis.MethodsA comprehensive search of MEDLINE, EMBASE, Web of Science, and Cochrane Library databases was conducted from their inception through February 2026. Studies reporting PMMA cement used as an interbody for pyogenic spondylodiscitis were included. Postoperative surgical site infections were excluded. Data were synthesized descriptively following scoping review framework (PRISMA-ScR).ResultsEight studies involving 203 patients (2013-2024) were identified. Common surgical indications included neurological deficit, instability, epidural abscess, and failure of medical management. Antibiotic-impregnated PMMA was used in seven studies (most commonly vancomycin + tobramycin or gentamicin). No major PMMA-related complications were reported, although one study mentioned a case of PMMA implant dislocation, requiring revision surgery during the same admission. Infection recurrence was low (1.4-1.6%). Fusion rates ranged from 95.9% to 100% when assessed (n=150). Fusion was commonly observed despite permanent PMMA implantation. Patient-reported outcomes were infrequently assessed but reported improvements in pain scores.ConclusionsLimited level IV evidence suggests that antibiotic-impregnated PMMA interbody placement is associated with high rates of infection control and fusion in pyogenic spondylodiscitis, particularly when significant endplate destruction is present and anterior column support is needed. No major PMMA-related complications were reported in the available literature. Well-designed comparative studies are warranted to clarify optimal patient selection, long-term durability, and the relative advantages of PMMA, if any, over contemporary reconstructive techniques.
Study DesignCross-sectional survey study.ObjectivesTo identify clinical knowledge gaps in spinal trauma and infection and assess use of AO Spine tools and recommendations.MethodsA 33-item online survey was distributed to AO Spine members by email and nonmembers through social media. Responses addressed demographics, case volume, knowledge gaps, and preferred educational formats. Descriptive statistics and regional comparisons using chi-squared or Fisher's exact tests were performed. Signficance was at the P < 0.05 level.ResultsOf 431 respondents, 412 completed at least one survey section and were included; the overall response rate could not be determined because the number of individuals who received or viewed the survey invitation was unavailable. Most respondents were orthopedic (61.2%) or neurosurgical (35.4%) surgeons. Leading priorities were osteoporotic spinal fractures (49.0%), spinal infection (48.3%), and fragility-associated low-energy sacropelvic fractures (40.3%). Regional variation was significant for sacropelvic fragility fractures (P = 0.038) and osteoporotic fractures (P = 0.028). Key gaps included bone quality optimization and surgical treatment for sacropelvic fragility fractures, comparison of techniques for osteoporotic fractures, and spinal infection algorithms. AO Spine Injury Classifications were routinely used by 89.5% of respondents. Use of the separate AO Spine-DGOU Osteoporotic Fracture Classification and AO Spine Primary Spine Infection Classification was reported by 35.7% and 18.7%, respectively, while PROST and CROST use was reported by 17.4% and 14.5%.ConclusionsSurgeons reported a need for standardized, evidence-based algorithms and accessible educational resources for osteoporotic fractures, spinal infection, and fragility-associated low-energy sacropelvic fractures.
Study DesignProspective multicenter observational cohort study.ObjectiveTo redefine mild degenerative cervical myelopathy (DCM) using a patient-reported severity framework derived from Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) and to compare surgical outcomes with the conventional clinician-reported definition.MethodsPatients with DCM undergoing surgery at 10 spine centers were enrolled. Mild DCM was defined using two criteria: a clinician-reported definition based on Japanese Orthopaedic Association (JOA) score (≧ 14.5) and a patient-reported definition derived from principal component analysis of JOACMEQ domains and Numerical Rating Scale (NRS) pain scores. Patients were categorized into four groups: Dual-Mild, Clinician-Mild, Patient-Mild, and Non-Mild. Postoperative outcomes were assessed using achievement of minimum clinically important difference (MCID) for JOA score, JOACMEQ, NRS, and Short Form-36 (SF-36). Multivariable logistic regression models were used to estimate adjusted probabilities of MCID achievement.ResultsAmong 930 eligible patients, 122 met criteria for mild DCM by each definition. Patients classified as Patient-Mild demonstrated higher baseline function and lower pain scores but showed significantly lower adjusted probabilities of achieving MCID in pain-related outcomes and SF-36 physical component summary (PCS) (odds ratio for PCS, 0.346 [0.196-0.589]; p < 0.001). In contrast, Clinician-Mild status was associated with sustained postoperative improvement.ConclusionDefinitions of mild DCM differ substantially between clinician- and patient-reported criteria. Patients who perceive their disease as mild exhibit limited postoperative improvement. Incorporating patient-reported severity into preoperative assessment may better inform expectations and shared decision-making regarding surgery in mild DCM.
Study DesignRetrospective cohort study.ObjectiveThe incidence of cervical radiculopathy is expected to increase by over 30% by 2050. ACDF, CDA, and PCF are established surgical options, each with distinct risk-benefit profiles. The objective of the present investigation is to compare long-term outcomes and complications among anterior cervical discectomy and fusion (ACDF), cervical disc arthroplasty (CDA), and posterior cervical foraminotomy (PCF).MethodsA retrospective analysis was conducted using TriNetX. Adult patients undergoing single-level ACDF, CDA, or PCF for cervical radiculopathy were identified. 1:1 propensity matching was performed. Outcomes included perioperative complications, reoperation rates, and new cervical pathology at 30 days, 90 days, 6 months, 1 year, 2 years, and 5 years. Statistical significance was set at p<0.05.ResultsMatched cohorts included ACDF vs. PCF (N=2,659), ACDF vs. CDA (N=3,749), and CDA vs. PCF (N=2,143). PCF demonstrated significantly higher reoperation rates at all timepoints compared to both ACDF and CDA in pairwise comparisons, (5-year: PCF 9.5 vs. ACDF 4.4%; PCF 10.0% vs. CDA 2.8%, p<0.001). ACDF patients demonstrated increased reoperation rates at 5 years (CDA 3.2% vs. ACDF 4.5%, p=0.01). ACDF was associated with higher early emergency department visits and ICU admissions compared to CDA.ConclusionsPCF was associated with higher rates of subsequent cervical reoperation compared with ACDF and CDA in the matched cohorts. Differences in early postoperative complications and healthcare utilization were also observed between procedures. These findings should be interpreted in the context of differences in surgical indications and unmeasured clinical and radiographic factors that may influence procedure selection.
Study Design Systematic review with guidelines. Objective To develop evidence-based, globally applicable recommendations for diagnosis and management of Tubercular spondylodiscitis (TBSD) as a part of the International Consensus Meeting (ICM) 2025 on Spinal Infection. Methods This article represents a structured, multi-phase international consensus process conducted under the auspices of ICM 2025. Systematic literature reviews were performed using PubMed, Scopus, Web of Science, and ClinicalTrials.gov in accordance with Cochrane methodology. Evidence synthesis was integrated with structured expert deliberation. Consensus statements were developed across 7 domains: screening and initial evaluation, imaging, microbiological diagnosis, anti-tubercular therapy, response monitoring and conservative management, surgical indications, and surgical techniques. Recommendations were finalised through structured voting, with levels of evidence assigned to each statement. Results The consensus emphasises early recognition, routine HIV screening, lesion-specific tissue diagnosis with drug-susceptibility testing, and a multimodal diagnostic strategy. MRI remains the primary imaging modality but lacks specificity for etiological differentiation. Six months of rifampicin-based chemotherapy is sufficient in clinically responding patients, irrespective of surgery. Surgery is indicated for neurological deficit associated with instability or deformity, progressive deterioration, or failure of conservative management. Posterior-only approaches are appropriate in most thoracic and lumbar cases, with anterior surgery reserved for selected indications. Conclusion The ICM 2025 recommendations provide a comprehensive, evidence-informed framework for the diagnosis and management of TBSD and aim to standardise care while guiding future research priorities worldwide.
Study Design Multiphase methodological framework for international consensus development. Objective This study describes the structured methodology adopted by the International Consensus Meeting on Infection - ICM 2025 (Spine Section) to formulate globally endorsed recommendations in musculoskeletal infection. The initiative aimed to standardise best practices in prevention, diagnosis, and management through a collaborative, evidence-driven process. Methods The consensus was developed through an 11-phase process spanning over 2 years, involving more than 100 global experts in orthopaedic infection. Phases included expert selection, question generation and ranking, systematic evaluation, literature synthesis, inter-delegate discussions, and a final face-to-face meeting. Recommendation statements were refined via iterative feedback and consensus-building techniques, including asynchronous dialogue and voting thresholds. Delegates were selected based on academic merit and regional representation, ensuring a diverse and multidisciplinary panel. Structured timelines ensured transparency and accountability across all phases. Results The outcome was a series of actionable, context-sensitive recommendations, reflecting high-level agreement across diverse healthcare settings. The methodology facilitated consensus on complex infection scenarios where definitive evidence was lacking, incorporating expert judgment and current literature. Conclusion The ICM 2025 (Spine Section) framework demonstrates a robust model for consensus development in orthopaedic surgery. Its transparent and scalable design ensures reproducibility for future topics requiring global guidance. This methodology sets a precedent for collaborative guideline generation in musculoskeletal care.
Study DesignMulticenter prospective cohort study.ObjectivesThis study aimed to determine whether concomitant cervical anterolisthesis influences surgical outcomes in patients with cervical spondylotic myelopathy (CSM).MethodsA total of 691 CSM patients were enrolled and classified into those with anterolisthesis ≥ 2 mm (Slip group, n=95) and those without measurable slip (Non-slip group, n=596). Patients underwent surgical treatment as indicated and were followed for 2 years. Cervical alignment, C2-7 ROM, JOA scores, JOACMEQ domains, and SF-36 scores were assessed. Clinical outcomes were compared using multivariate analyses adjusted for baseline factors. A subgroup analysis evaluated high-grade slip (≥4 mm).ResultsThe Slip group was older and had more kyphosis and worse baseline lordosis and JOA score. Fusion was performed more frequently in the Slip group, which also showed a greater reduction in cervical ROM at 2 years. Adjusted postoperative JOA score, JOACMEQ, and SF-36 outcomes were comparable between groups postoperatively. Within the Slip group, high-grade slip (≥4 mm) was associated with less JOA improvement in an exploratory subgroup analysis, whereas JOACMEQ and SF-36 scores were not influenced by slip severity.ConclusionsNeutral-radiograph-defined cervical anterolisthesis ≥2 mm was not independently associated with worse adjusted 2-year neurological, functional, or quality-of-life outcomes. High-grade slip (≥4 mm), however, may limit neurological recovery, underscoring the importance of evaluating segmental stability when substantial slippage is present.
Study DesignCross-sectional survey.ObjectiveOutcomes research has significantly shaped patient management in spine deformity care, while the dissemination of research remains a challenge. To guide future research directions, this study surveyed AO Spine members to identify the research needs, dissemination methods, and existing knowledge gaps.MethodsAn anonymous, English-language survey containing 40 questions explored knowledge gaps, research priorities, and knowledge translation practices. Distributed via email to AO Spine members globally, the questionnaire collected responses from March 20 to April 14, 2025.Results399 responses were received from mostly orthopedic surgeons, 28% from Asia Pacific, 27% from Europe and South Africa, 18% from Latin America, 16% from North America, and 11% from the Middle East and North Africa. Of the 279 respondents focused on deformity surgery, most utilized classification tools, clinical guidelines, and multicenter study findings for decision-making. However, over half were unaware of past Knowledge Forum Deformity resources, indicating a dissemination gap. Key sources of information were publications, conferences, and AO Spine courses. Major barriers to implementing new tools included workflow integration and administrative challenges. Top research priorities were the development of diagnostic and treatment guidelines (71%) and prediction algorithms (69%). Prominent knowledge gaps included proximal junctional kyphosis (PJK) (69%), spinal alignment guidelines (54%), and osteoporosis management (52%).ConclusionThe survey highlights PJK, spinal alignment, and osteoporosis as the leading knowledge gaps. Priorities for future research include developing guidelines and prediction tools. Improved dissemination strategies are needed to enhance clinical adoption and inform ongoing research and education initiatives.
Study DesignRetrospective cohort study of prospectively enrolled patients.ObjectivesTo evaluate the association between postoperative slip reduction and improvement in disability and low back pain (LBP) after lumbar fusion for low-grade degenerative spondylolisthesis (DLS), and to determine whether outcomes are independently associated with slip reduction or with sagittal alignment changes.Methods160 patients undergoing lumbar fusion for low-grade DLS were analyzed. Slip reduction was quantified on lateral radiographs as absolute change in relative slippage normalized to vertebral body dimensions. Disability and LBP were assessed using the Oswestry Disability Index (ODI) and numeric rating scale (NRS) preoperatively and at two years. Associations between slip reduction and improvement in ODI and LBP were analyzed using multivariable linear regression adjusted for demographics, baseline symptoms, fusion length, and preoperative slippage.ResultsSlip reduction was independently associated with greater improvement in ODI and LBP (both p<0.001) at two years. Although slip reduction correlated with changes in segmental slip angle, lumbar lordosis, and PI-LL (all p≤0.001), these alignment parameters were not independently associated with clinical outcomes (all p>0.05).ConclusionsPostoperative slip reduction was independently associated with greater improvement in disability and LBP among patients undergoing lumbar fusion with attempted reduction for low-grade DLS, whereas associated changes in sagittal alignment were not. However, given the moderate explanatory power of the regression models, slip reduction should be interpreted as one of several factors associated with postoperative outcomes. As this was an observational analysis, residual confounding by indication cannot be excluded, and prospective validation is warranted to further define the role of slip reduction in surgical decision-making.
