Adult spinal deformity (ASD) alters sagittal alignment and trunk centre of mass location, increasing spinal loading. Current clinical assessment of ASD primarily focuses on alignment parameters disregarding patient’s body shape variability. This study aimed to evaluate the relative effects of spinal sagittal alignment and body mass distribution (i.e., body shape) on spinal loads and trunk centre of mass location in upright-posture and forward flexion. Sagittal alignments of 754 patients with ASD were obtained from clinical data. Trunk mass distributions were assessed in adult male volunteers (10 healthy weight, 9 obese). Using an established musculoskeletal model of the spine, inverse dynamics simulations were performed for each combination of sagittal alignment and trunk mass distribution profile. A factorial analysis using generalised linear models elucidated the relative effects of alignment vs. body shape. Sagittal alignment primarily determined the antero-posterior positioning of trunk centre of mass; body shape, its cranio-caudal location. In the healthy weight cohort, the relative effect of mass distribution on compressive loads was 14–98

Instability of the craniocervical junction is a potentially life-threatening condition requiring surgical stabilization. Traditional occipital plate fixation carries risks of construct loosening and intracranial complications due to variable skull thickness, particularly after posterior fossa decompression where plate fixation is challenging. Occipital condyle screws (OCS) provide direct fixation into the occipital condyles (OCs). However, comprehensive outcome data remains sparse. This systematic review and meta-analysis evaluated anatomical parameters, technical aspects, and surgical outcomes of OCS fixation in craniocervical stabilization. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, PubMed/MEDLINE, Embase, and Scopus were searched for studies reporting techniques and outcomes of occipitocervical fixation using OCS. Two reviewers independently extracted data, and study quality was assessed using the Newcastle-Ottawa Scale, when possible. Random-effects meta-analysis was performed. The primary endpoint was to characterize the technical aspects of craniocervical fixation using OCS and to ascertain its overall feasibility, defined by morphometric suitability, technical success rates, and complication rates. Thirty studies met inclusion: 12 cadaveric (618 specimens), 10 imaging (1,604 participants), and 8 surgical (284 patients). Morphometry consistently showed larger OC in male populations. Bicortical screw placement achieved 100% technical success. Standard 3.5-mm screws (18–24 mm) were commonly used. Recommended trajectories varied (sagittal with 18°–28° angulation; axial with 22°–37° angulation). No major symptomatic vascular or permanent neurological complications occurred. Meta-analytic data revealed significant differences in morphometric measurements of the OC and differences in the OCS length and angulation parameters. OCS fixation appears to be an anatomically feasible and technically promising fixation strategy in selected patients when anatomy and technique are carefully evaluated. Population-specific morphometric variability mandates individualized preoperative assessment. Future comparative studies should define long-term outcomes, fusion rates, and optimize region-specific surgical parameters.

While cervical arthroplasty using Total Disc Replacement (TDR) implants is an established treatment for persistent neck and arm pain, revision rates limit it from reaching its full potential. To address the underlying complications, we developed finite element simulation-driven design optimizations for a TDR’s bone-implant interface and motion-preservation features. These automated processes explored high-dimensional design spaces iteratively through analysis of design variations interplay with spinal structures. The optimizations were metamodel-based using artificial neural networks and a hybrid optimizer. They optimized the motion-preservation zone towards replicating the asymptomatic spinal segment’s ligaments strain profiles and its facet joint force profiles during main motions. This design process aims to minimize the risk for postoperative pain, avoidable degeneration and to restore segmental biomechanics, to prevent adjacent segment effects. Designs with single articulation and with dual articulation (with a mobile insert) were optimized. The bone-implant interface was optimized with the aim to minimize the risk for subsidence and implant migration. The optimizations improved the multi-objective value of the bone-implant interface by 14.6% and that of the motion-preservation zone by 36.1%. Implant migration, the leading cause of revisions, was reduced by 24.8%. With this, we show the potential of simulation-driven implant design optimization for addressing complex clinical challenges.

Background:Surgical strategies for recurrent lumbar disc herniation (ReLDH) range from repeat microdiscectomy (MD) to instrumented fusion (IF). Identifying predictive factors for surgical treatment could improve patient selection and outcomes. The primary objective of this study was to investigate the impact of Modic changes (MC) on clinical outcomes, radiological progression, and re-operation rates in ReLDH. The secondary objective was to compare outcomes between MD and IF stratified by MC patterns to determine whether MC assessment can guide surgical decision-making. Methods:This is a pre-planned subgroup analysis from a single-center retrospective cohort study of prospectively collected registry data. We analyzed 450 consecutive patients who underwent surgery for ReLDH (MD: n = 316, IF: n = 134) from 2004 to 2024. Radiological assessment included T1-and T2-weighted magnetic resonance imaging (MRI) sequences analyzing presence and type of MC, disc height, and Pfirrmann grade of the affected segment, and spinopelvic parameters on standing radiographs. Persistent MC were defined as maintaining the same Modic type at both index and revision surgery (e.g., Type 1→Type 1). Patient-reported outcome was assessed using the Core Outcome Measures Index (COMI) and achievement of Minimal Clinical Important Change (MCIC ≥2.2 points) up to 5 years postoperatively. Re-operation rates, time to re-operation, and rates of subsequent re-revision surgery were analyzed for both surgical groups, with at least 5 years of follow-up. Results:Patients with persistent MC Type 1 (n = 64; MD: 41, IF:23) demonstrated the shortest median time to revision (0.58 years) compared to no MC (1.03 years, p = 0.012). Persistent MC Type 1 demonstrated the highest re-revision rate among all MC patterns following MD (48.8%), which was dramatically reduced with IF (13.0%, p < 0.05), representing a 3.7-fold risk reduction. Overall re-revision rates were 36.7% for MD versus 15.7% for IF (p < 0.001). Persistent MC Type 1 pattern showed accelerated disc degeneration with progression to Pfirrmann grade 5 in 29.7% (vs 5.8% in no MC, p < 0.001) and severe disc height loss (>30% height loss) in 20.3%. While COMI outcomes showed no significant differences between surgical approaches at any timepoint, IF demonstrated numerically greater improvement at 2 years (5.3 vs 3.5 points, p = 0.692; derived ODI: 33.1 vs. 25.9). MCIC achievement in persistent MC Type 1 patients showed no significant differences at any time point: 3 months (65.0% IF vs 47.8% MD), 1 year (63.2% IF vs 64.7% MD), 2 years (76.9% IF vs 70.6% MD), and 5 years (66.7% IF vs 66.7% MD). Conclusion:Persistent Type 1 MC represent a distinct high-risk phenotype in ReLDH characterized by early recurrence, elevated re-revision rates, and accelerated segmental degeneration, compared to other MC types. The 3.7-fold reduction in re-revision rates and superior functional outcomes with IF provide compelling evidence, that warrant consideration in surgical decision-making.

Introduction:Spinal cord damage in Degenerative Cervical Myelopathy (DCM) makes it a distinct subgroup of degenerative cervical spine disorders, as the central nervous system is affected. Research question:Are the pattern and extent of change in patient-reported outcomes over time comparable between patients with DCM and those with other degenerative cervical spine disorders? Material and methods:Pre-operatively and at 3, 12, 24 and 60 months' follow-up (Time factor), patients undergoing cervical spine surgery for degenerative disorders completed a questionnaire comprising the Core Outcome Measures Index (COMI, 0-10), Patient-Acceptable Symptom State (PASS, dichotomised as yes/no), and Global Treatment Outcome (GTO, dichotomised as good/poor). Patients with DCM and controls (Group factor) were propensity-score matched based on baseline and surgical variables. Data were analysed using General Estimating Equations. Results:708 patients (354 DCM, 354 controls; 61.7 ± 10.7 years; 43% female) could be matched and analysed. Time was statistically significant for all outcomes (p < 0.01), but Group only for GTO (p = 0.001). The Time × Group interaction was not significant (COMI p = 0.101; PASS p = 0.062; GTO p = 0.152), indicating similar changes over time for both groups. PASS improved significantly from baseline up to 12 months and COMI up to 24 months. Overall, 7.5% fewer DCM patients than controls reported a good GTO (p = 0.002). Discussion and conclusion:Recovery patterns over time were similar in DCM and control patients. Differences were observed only for GTO, with fewer DCM patients rating their surgical outcome as good, although COMI and PASS were comparable between the groups.

Background: Optimal surgical treatment for recurrence of lumbar disc herniation (LDH) remains controversial, with options ranging from repeat microdiscectomy (MD) to instrumented fusion (IF). This study aimed to guide surgical decision-making by analyzing reoperation rates, clinical and radiographic risk factors for treatment failure, and functional outcomes following MD versus IF. Methods: Prospectively collected data from 450 patients in our outcomes database who underwent surgery for recurrent LDH from 2004 through 2023 were retrospectively analyzed. Clinical assessment included predominant symptoms, neurological deficits, and American Society of Anesthesiologists (ASA) grade. Radiographic assessment included disc height, Pfirrmann grade, facet angle, and Modic changes on magnetic resonance imaging, as well as spinopelvic parameters on standing radiographs. Patient-reported outcomes were assessed using the Core Outcome Measures Index (COMI) and achievement of the minimal clinically important change (MCIC) of ≥2.2 points. Propensity-score matching (PSM) was performed to control for confounding factors. Reoperation rates were analyzed with a minimum 5-year follow-up. Results: Of 450 patients with recurrent LDH, 316 (70.2%) underwent MD and 134 (29.8%) underwent IF. In 192 patients after PSM, IF showed nonsignificantly higher MCIC achievement (odds ratio [OR] = 1.20, 95% confidence interval [CI]: 0.66 to 2.17, p = 0.65) and lower COMI scores compared with the MD group (3.34 ± 2.89 versus 4.01 ± 2.95, p = 0.059; derived Oswestry Disability Index [ODI]: 23.8 versus 28.1). IF demonstrated significantly lower reoperation risk compared with MD (15.7% [116/316] versus 36.7% [21/34], p < 0.001). The reoperations following MD were predominantly subsequent IF (73.3%) and repeat MD (23.3%), while the reoperations after IF were predominantly adjacent segment surgery (57.1%) and hardware revision (33.3%). BMI of ≥35 kg/m 2 was a significant predictor of reoperation after MD (univariate OR = 3.63, p = 0.039), while disc height of <6 mm (OR = 1.97) and Modic type-1 changes (OR = 1.78) showed trends toward increased reoperation risk (both p < 0.10). Conclusions: Although both procedures achieved clinical improvement, IF demonstrated superior long-term durability as shown by significantly lower reoperation rates over extended follow-up. Our findings support a risk-stratified surgical selection: IF should be strongly considered in patients with BMI of ≥35 kg/m 2 and those with progressive disc degeneration, whereas MD remains appropriate for patients without these risk factors. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT In lumbar degenerative spondylolisthesis, the optimal initial surgical approach remains debated. While fusion provides immediate stabilization, decompression alone may be sufficient in selected patients, potentially avoiding the morbidity and cost of fusion. However, some patients subsequently require fusion after initial decompression. Whether this staged approach affects long-term outcomes compared with primary fusion remains unclear. PURPOSE To compare clinical outcomes of patients undergoing fusion after prior decompression versus those undergoing primary fusion for lumbar degenerative spondylolisthesis. STUDY DESIGN/SETTING Retrospective cohort study using registry data. PATIENT SAMPLE Patients with lumbar degenerative spondylolisthesis who underwent (1) fusion following prior decompression (n=63) or (2) primary fusion (n=943). OUTCOME MEASURES Core Outcome Measures Index (COMI), Global Treatment Outcome (GTO), and Patient Acceptable Symptom State (PASS) at 12 months postfusion. METHODS Propensity score matching (1:1, nearest neighbor, caliper 0.1) was performed to control for baseline differences prior to fusion. Matching variables included age, sex, BMI, smoking status, baseline COMI score, and Graphic Rating Scale (GRS) scores for low back and leg pain. Outcomes were assessed at 12 months postoperatively. Independent t-tests were used for comparisons, with effect sizes reported as Cohen’s d. RESULTS A total of 63 matched pairs were identified. The median time between decompression and subsequent fusion in the prior decompression group was 29.6 months (range: 2.5–421.7 months). At 12 months postfusion, no significant differences were observed between groups. Outcomes for the prior decompression versus primary fusion groups were: COMI 3.3±2.6 vs 2.8±2.7 (p=0.28; Cohen’s d=0.19), GTO 1.8±1.1 vs 1.5±0.7 (p=0.06; Cohen’s d=0.35), and PASS 2.5±1.5 vs 2.2±1.4 (p=0.21; Cohen’s d=0.21). CONCLUSIONS Patients undergoing decompression followed by subsequent fusion demonstrate comparable 12-month outcomes to those undergoing primary fusion, with no statistically or clinically meaningful differences. These findings suggest that secondary fusion after initial decompression does not compromise patient-reported outcomes. Limitations include the observational design and lack of radiographic data. Prospective studies are needed to identify patients who may avoid fusion after decompression and to evaluate longer-term outcomes. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

Introduction Surgical site infections (SSIs) are significant complications that can occur after spine surgery. Compared with systemic infections such as sepsis, or localised musculoskeletal infections such as periprosthetic joint infection, the immune responses in postoperative infection of the spine are poorly understood. A deeper understanding may provide clinically relevant diagnostic or therapeutic options.Methods This study examined changes in immune cell profiles in the blood of patients who developed infections after spinal surgery (Infection group, I, n = 17) compared to control patients without infections (Non-infection, NI, n = 20). The two groups were matched by age, body mass index (BMI), and the invasiveness of the surgical procedure. Peripheral blood mononuclear cells (PBMCs) were collected after surgery and subjected to high-dimensional mass cytometry.Results Cluster analysis identified 46 immune cell clusters, 30 of which exhibited significant differences between the I and NI patients. Natural killer cells as well as myeloid dendritic cells were decreased in I patients compared to NI patients (p=0.0269; and p=0.0267, respectively). Conversely, Th17, CD69+ and HLA-DR+ CD4+ T cells were significantly increased in I patients compared to NI patients (p=0.0422, p=0.0267; p=0.0267, respectively). ROC curve analysis of immune cell counts demonstrated potential for differentiating NI from I patients.Discussion This study reveals that patients with SSI exhibit a significantly altered immune cell profile, with greatest differences observed in increased HLA-DR+ CD4+ T cells and decreased numbers of several innate immune cells. The diagnostic potential of these markers may prove clinically relevant, and further research into the impact of activation and exhaustion may yield future therapeutic strategies.

BACKGROUND:Optimal surgical treatment for recurrence of lumbar disc herniation (LDH) remains controversial, with options ranging from repeat microdiscectomy (MD) to instrumented fusion (IF). This study aimed to guide surgical decision-making by analyzing reoperation rates, clinical and radiographic risk factors for treatment failure, and functional outcomes following MD versus IF. METHODS:Prospectively collected data from 450 patients in our outcomes database who underwent surgery for recurrent LDH from 2004 through 2023 were retrospectively analyzed. Clinical assessment included predominant symptoms, neurological deficits, and American Society of Anesthesiologists (ASA) grade. Radiographic assessment included disc height, Pfirrmann grade, facet angle, and Modic changes on magnetic resonance imaging, as well as spinopelvic parameters on standing radiographs. Patient-reported outcomes were assessed using the Core Outcome Measures Index (COMI) and achievement of the minimal clinically important change (MCIC) of ≥2.2 points. Propensity-score matching (PSM) was performed to control for confounding factors. Reoperation rates were analyzed with a minimum 5-year follow-up. RESULTS:Of 450 patients with recurrent LDH, 316 (70.2%) underwent MD and 134 (29.8%) underwent IF. In 192 patients after PSM, IF showed nonsignificantly higher MCIC achievement (odds ratio [OR] = 1.20, 95% confidence interval [CI]: 0.66 to 2.17, p = 0.65) and lower COMI scores compared with the MD group (3.34 ± 2.89 versus 4.01 ± 2.95, p = 0.059; derived Oswestry Disability Index [ODI]: 23.8 versus 28.1). IF demonstrated significantly lower reoperation risk compared with MD (15.7% [116/316] versus 36.7% [21/34], p < 0.001). The reoperations following MD were predominantly subsequent IF (73.3%) and repeat MD (23.3%), while the reoperations after IF were predominantly adjacent segment surgery (57.1%) and hardware revision (33.3%). BMI of ≥35 kg/m 2 was a significant predictor of reoperation after MD (univariate OR = 3.63, p = 0.039), while disc height of <6 mm (OR = 1.97) and Modic type-1 changes (OR = 1.78) showed trends toward increased reoperation risk (both p < 0.10). CONCLUSIONS:Although both procedures achieved clinical improvement, IF demonstrated superior long-term durability as shown by significantly lower reoperation rates over extended follow-up. Our findings support a risk-stratified surgical selection: IF should be strongly considered in patients with BMI of ≥35 kg/m 2 and those with progressive disc degeneration, whereas MD remains appropriate for patients without these risk factors. LEVEL OF EVIDENCE:Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Intervertebral disc degeneration may require spinal fusion surgery using interbody cages. Implant subsidence remains a significant complication, largely attributed to the stiffness mismatch between interbody cages and vertebral endplates. While porous cage designs aim to reduce their stiffness, they do not account for patient-specific anatomical and mechanical variability. This study aims to evaluate whether patient-specific, topology optimized interbody cages improve load distribution and decrease subsidence risk compared with offthe-shelf cages in a human cadaveric mechanical model. Methods: Sixteen functional spinal units (FSUs) were allocated by bone quality to topology-optimized devices (TOD) or off-the-shelf (OTS) cage groups. Both cage types were designed for a TLIF approach (TOD by a previously developed topology optimization method) with the same footprint and additively manufactured from medical-grade titanium alloy. Endplate contact was assessed using pressure-sensitive film. FSUs underwent axial compression to failure at 1 mm/min with optical displacement tracking. Failure (subsidence) force is defined as the first local maximum of the force-displacement curve. Results: Pressure film analysis demonstrated broader and more uniform endplate contact for TOD cages, whereas OTS cages exhibited concentrated edge loading. Failure (subsidence) force and integral volumetric bone mineral density (vBMD) were positively correlated for both cage groups. Paired comparisons showed a significantly higher failure (subsidence) force (increase of median force by 97.6%) for TOD implants (median force: 876.5 N) compared to OTS implants (median force: 443.7 N; p = .03). Conclusions: Patient-specific topology optimized interbody cages improved endplate conformity and load distribution, resulting in higher resistance to subsidence compared to conventional off-the-shelf cages. These findings suggest that patient-specific topology optimized interbody cages may offer a biomechanically advantageous solution for spinal fusion, especially in patients with compromised bone quality, with the potential to reduce implant subsidence and improve clinical outcomes.

Introduction Spine registries are important for advancing the field to provide evidence for clinical and health policy decision-making. Research question The objective is to introduce the Swiss Implant Registry "SIRIS Spine" as one of the world’s first mandatory nationwide spinal implant registries for selected spinal surgeries. Material and Methods SIRIS Spine is governed by the SIRIS Foundation, Switzerland. EUROSPINE is commissioned to operate the registry. Collected patient data includes demographic, clinical, and implant information and may additionally include electronic patient-reported outcome measures. Inclusion criteria are growing stepwise. Results Between the years 2021-2023, 12,815 surgeries for 11,789 patients from 91 hospitals were registered. This includes 75,522 implants from 40 manufactures. Reoperations and revisions were registered in 6.9%. The most frequent pathology was degenerative disease (61.6%), followed by osteoporotic fractures (12.4%), and non-degenerative spondylolisthesis (5.4%). The mean age was 66.8 (standard deviation (SD) 13.7) years. Women (58.7%) were slightly more frequently included than men. Almost half of the surgeries were preceded by one or several prior surgeries at the same or adjacent segment (49.6%), after excluding 1’367 patients with missing information. Discussion and Conclusion The SIRIS Spine registry has successfully captured initial data from the involved Swiss hospitals. Involvement of all key stakeholders including specialist societies has proven to be important and a clear success factor. The primary challenge identified was the complexity of inclusion criteria, which has impeded data validation. Future efforts will focus on simplifying criteria, rigorously validating data completeness and accuracy, and leveraging data for quality improvement and comparative analyses.

(1) Cage subsidence in spine surgery is a frequent clinical challenge. This study aimed to assess a novel screw augmentation technique for Transforaminal Lumbar Interbody Fusion in cadavers of reduced bone mineral density (BMD). (2) Forty human lumbar vertebrae (BMD 84.2 ± 24.4 mgHA/cm3, range 51–119 mgHA/cm3) were assigned to two groups: augmenting screw group and control group. The augmentation technique comprised placement of two additional subcortical screws. Ten constructs per group were loaded with a quasi-static load-to-failure protocol and other ten were cyclically loaded. Failure modes were documented. (3) During the quasi-static load-to-failure testing, the augmenting screw technique showed a significantly higher failure load (1426.0 ± 863.6 N) versus the conventional technique in the control group (682.2 ± 174.5 N, p = 0.032). Cyclic loading revealed higher number of cycles and corresponding load until reaching 5 mm subsidence and significantly higher number of cycles and corresponding load until reaching 10 mm subsidence for the augmenting screw technique (9645 ± 3050; 1164.5 ± 305.0 N) versus the conventional technique in the control group (5395 ± 2340; 739.5 ± 234.0 N, p < 0.05). Failure modes were different and showed bending of the augmenting screws, followed by cut-out. (4) The investigated augmenting screw technique demonstrated higher failure loads and cycles to failure against cage subsidence compared to conventional cage placement. Failure modes were different between the two techniques and may lead to a different kind of complications.

In 1998, an international and multidisciplinary group of experts (from the fields of spine surgery, physiotherapy, occupational therapy, rheumatology, primary care medicine, internal medicine, health economics and epidemiology) proposed a short multidimensional series of core outcome items for use in patients with low back disorders. In 2005 and 2006, two independent research groups published studies validating these items when combined to form an outcome instrument that was subsequently coined the Core Outcome Measures Index for the back (COMI-back). It now exists in at least 22 languages, is used as the primary outcome measure in numerous research studies, and has been adopted by International and National Surgical and Non-Surgical Spine Registries. Its Minimal Clinically Important Change score (MCIC) for both improvement and worsening have been calculated. It has been shown to be as responsive an outcome measure as many other, long-standing legacy outcome measures (e.g. Oswestry Disability Index, ODI) and various condition-specific instruments used in assessing patients with specific pathologies such as spinal stenosis, spinal deformity, or spinal tumour. A cross-walk to convert COMI scores to ODI scores has been developed. Other musculoskeletal specialties have taken the COMI-back and modified the wording to reflect the joint being enquired about to produce COMI-neck, COMI-knee and COMI-hip versions; these have been subsequently validated for use in patients with the corresponding musculoskeletal disorders. Predictor studies using machine-learning methods and sophisticated statistical analyses have been carried out to predict post-surgical COMI scores, based on a minimal set of baseline characteristics. Part 1 of this review gives an overview of the development of the COMI and its success as a brief but responsive multidimensional outcome instrument over the last 18 years, whilst Part 2 serves to describe its content, scoring, language versions and applications.

The superior aspect of the unilateral laminotomy for bilateral decompression (ULb) typically corresponds with the superior ligamentum flavum attachment. Unlike lateral expansion, cranial expansion is considered a viable option to ensure sufficient decompression. The aim of this study was to investigate how cranial expansion affects the biomechanical stability in the lumbar spine. Range of motion of eight fresh-frozen human cadaveric L1-L5 specimens was assessed in flexion-extension, lateral bending (LB), and axial rotation (AR). The workflow comprised testing in the intact state and after L3-4 ULb with sequential increase of the cephalad extent over 4 steps: (1)25

Biomechanical investigation is needed to determine whether stand-alone anterior lumbar interbody fusion with integrated screws (ALIF) is advisable for use in elderly patients. This study aimed to test three null hypotheses: (1) cyclic loading does not cause loosening of ALIF in degenerated lumbar specimens, (2) cyclic loading does not cause loosening in transforaminal lumbar interbody fusion (TLIF) in degenerated lumbar specimens, and (3) Neutral Zone (NZ) and Range of motion (ROM) of ALIF and TLIF do not differ after cyclic loading. Twelve fresh-frozen human cadaveric lumbar motion segments (L1-5, donors’ age 76.1 ± 6.7 years; trabecular BMD 97.1 ± 36.9 mgHA/cm3) were utilized. NZ and ROM were assessed after ALIF or TLIF and following cyclic loading for flexion-extension (Flex-Ext), lateral bending (LB), and axial rotation (AR). Axial compression of 0–1150 N was applied over 2000 cycles. Loosening was defined as significant increase in NZ. Cyclic loading significantly increased NZ of ALIF specimens in Flex-Ext (1.69 ± 1.81°, p =.048) and LB (1.84 ± 1.81°, p =.036), and showed a trend to significance in AR (0.46 ± 0.54°, p =.065). NZ of TLIF specimens did not increase significantly in any motion direction (p ≥.112). ROM and NZ did not differ significantly between ALIF and TLIF in post-cyclic states(p ≥.556). Axial compression loading caused significant loosening of ALIF in Flex-Ext and LB, but not of TLIF in degenerated lumbar human cadaveric specimens. Hence, standalone ALIF cannot be recommended without reservation for the use in elderly patients with degenerative lumbar spines. However, the absolute differences between pre- and post-cyclic states were small, and ROM and NZ of ALIF after cyclic loading were comparable to TLIF.

The Neck Disability Index (NDI) and the neck version of the Core Outcome Measures Index (COMI-neck) are two commonly used self-rating outcome instruments in patients with cervical spinal disorders. The present study aimed to create a crosswalk between them to allow the scores of one to be interpreted in terms of the other. We performed a secondary analysis of matched pairs of NDI and COMI-neck data collected in an international spine surgery registry from 624 patients (51 ± 10y; 57.2

In 1998, an international and multidisciplinary group of experts (from the fields of spine surgery, physiotherapy, occupational therapy, rheumatology, primary care medicine, internal medicine, health economics and epidemiology) proposed a short multidimensional series of core outcome items for use in patients with low back disorders. In 2005 and 2006, two independent research groups published studies validating these items when combined to form an outcome instrument that was subsequently coined the Core Outcome Measures Index for the back (COMI-back). It now exists in at least 22 languages, is used as the primary outcome measure in numerous research studies, and has been adopted by International and National Surgical and Non-Surgical Spine Registries. Its Minimal Clinically Important Change score for both improvement and worsening have been calculated. It has been shown to be as responsive an outcome measure as many other, long-standing legacy outcome measures (e.g. Oswestry Disability Index-ODI) and various condition-specific instruments used in assessing patients with specific pathologies such as spinal stenosis, spinal deformity, or spinal tumour. A cross-walk to convert COMI scores to ODI scores has been developed. Other musculoskeletal specialties have taken the COMI-back and modified the wording to reflect the joint being enquired about to produce COMI-neck, COMI-knee and COMI-hip versions; these have been subsequently validated for use in patients with the corresponding musculoskeletal disorders. Predictor studies using machine-learning methods and sophisticated statistical analyses have been carried out to predict post-surgical COMI scores, based on a minimal set of baseline characteristics. Part 1 of this review gives an overview of the development of the COMI and its success as a brief but responsive multidimensional outcome instrument over the last 18 years, whilst Part 2 serves to describe its content, scoring, language versions and applications.

Cervical spondylosis can cause loss of lordosis or even kyphosis, altering sagittal alignment and triggering compensatory mechanisms to maintain horizontal gaze. Despite the widespread use of multilevel anterior cervical discectomy and fusion (ACDF), its impact on cervical sagittal alignment and compensatory mechanisms remains unclear. This study investigates degenerative changes in cervical sagittal alignment and compensatory mechanisms before and after multilevel ACDF. A retrospective analysis was conducted on 290 patients who underwent multilevel ACDF (2–3 levels) for cervical spondylosis. Preoperative and postoperative sagittal parameters including C0–C2 lordosis, C2–C7 lordosis, surgical (fused-level) lordosis, unfused-level lordosis, T1 slope (T1S), T1S minus cervical lordosis (T1S–CL), and cervical sagittal vertical axis (c–SVA) were measured using a previously described deep learning model. Demographic data were collected at the same time points. Changes from baseline to follow-up were calculated. Correlations between changes in surgical lordosis and sagittal parameters were assessed via linear regression, Pearson’s correlation, and multiple logistic regression analysis. Mean preoperative C2–C7 lordosis was 11.4° ± 13.7°, increasing by 6.5° in two-level, and 8.6° in three-level ACDF patients. Statistically significant improvements were observed in C2–C7 lordosis, C0–C2 lordosis, and T1S–CL mismatch (all p < 0.01). Changes in surgical lordosis correlated negatively with changes in unfused segment lordosis (R = − 0.26, p < 0.01). The strongest negative correlation was observed between changes in C2–C7 and changes in C0–C2 lordosis (R = − 0.60, p < 0.01), highlighting subaxial realignment’s impact on upper cervical compensation. A moderate positive correlation emerged between changes in surgical lordosis and changes in T1S (R = 0.29, p < 0.01). Subgroup analyses by fusion area confirmed the consistency of these relationships across different ACDF configurations. Multilevel ACDF leads to a gain of surgical lordosis and reduces compensatory mechanisms. By recognizing and accounting for preoperative compensatory mechanisms, surgeons can optimize surgical planning to achieve a more stable and biomechanically favorable alignment. We propose a three-step algorithm to analyze cervical sagittal alignment and take into consideration the presence of compensatory mechanisms of the upper cervical, the unfused subaxial and when available the global spine. IV.

Das Grisel-Syndrom ist eine seltene, aber potenziell schwerwiegende Komplikation nach Infektionen oder chirurgischen Eingriffen im HNO-Bereich. Es betrifft vorwiegend Kinder im Alter von 6 bis 12 Jahren. Erstmals 1930 von Pierre Grisel beschrieben, beruht seine Pathophysiologie auf dem Zusammenspiel einer infektionsbedingten Entzündung und einer erhöhten ligamentären Laxität der kindlichen Halswirbelsäule. Etwa 60% der Fälle treten nach Infektionen der oberen Atemwege auf, 40% nach HNO-Eingriffen – insbesondere nach Adenotonsillektomien. Klinisch zeigt sich das Syndrom typischerweise mit schmerzhaftem Torticollis und eingeschränkter Kopfbeweglichkeit, in fortgeschrittenen Fällen auch mit neurologischen Symptomen. Eine frühzeitige klinische und radiologische Diagnosestellung ist entscheidend, um eine adäquate Therapie einzuleiten. In der Regel erfolgt die Behandlung konservativ mit Schmerzmitteln, entzündungshemmender Medikation und ggf. Antibiotikagabe. Eine chirurgische Stabilisierung ist bei verzögerter Diagnose, Therapieversagen oder schwerer Subluxation erforderlich. Die Kenntnis der klinischen Symptomatik ist essenziell, um rechtzeitig intervenieren zu können und schwere neurologische Komplikationen oder Funktionseinschränkungen zu vermeiden.