BACKGROUND CONTEXT:Lumbar spine fusion is frequently performed to eliminate motion between vertebrae and thereby relieve symptoms. However, there is currently no clinically validated, biomechanically rational standard for diagnosing failure to achieve this surgical goal. A strain-based method has recently shown promise in assessing fusion status after cervical spine surgery. Its applicability to the lumbar spine remains unknown. PURPOSE:To evaluate the feasibility and performance of a strain-based approach for assessing lumbar spine fusion status. STUDY DESIGN:Retrospective analysis of lumbar flexion-extension radiographs obtained following fusion surgery. METHODS:Using FDA-cleared automated software, intervertebral strain was calculated from anatomic landmarks on flexion-extension radiographs obtained at multiple time points (3-60 months) following posterior-lateral (PL) or PL plus interbody (PL+IB) fusion. Strain values were categorized as: Motion Compatible with Bridging (MCB), Uncertain, or Motion Incompatible with Bridging. The percentage of levels in each category was determined over time and compared between fusion types. Adjacent-level strain was also evaluated. A proof-of-concept convolutional neural network was trained on motion-stabilized image pairs to classify uncertain levels. RESULTS:Strain data were analyzed for 1,958 PL and 2,079 PL+IB fusion levels. PL+IB fusions demonstrated a faster reduction in intervertebral strain. By 60 months, average strain was <5% for both fusion types, with 86% of PL and 90% of PL+IB levels classified as MCB. Adjacent-level strain increased slightly after fusion surgery. The convolutional neural network correctly classified 96% of levels as MCB or Motion Incompatible with Bridging and reduced the proportion of uncertain cases from 21% to 5%. CONCLUSIONS:A strain-based method provides an objective, biomechanically grounded, and automated approach for monitoring fusion progression after lumbar spine surgery. A neural network can enhance this method by reducing the need for subjective review of borderline cases. CLINICAL SIGNIFICANCE:Strain-based fusion assessment enables standardized, reproducible, and scalable evaluation of postsurgical spinal motion. With further validation, it may improve clinical decision-making and facilitate more consistent outcomes reporting in spine surgery research.

Background Manual line drawings in spinal assessments are associated with poor accuracy and reproducibility, while many AI models lack validation. A semi-automated image analysis technology, Quantitative Motion Analysis (QMA), has been used to produce radiographic measures in over 300 clinical trials of spinal treatment and shown to have sub-degree and sub-millimeter accuracy (0.47° and 0.54 mm on average). Recently, a fully automated analysis pipeline of AI models has been developed to provide equivalent accuracy and reliability of QMA in clinical workflow. The objective of this study is to present a direct comparison between motion measurements obtained by a fully automated image analysis tool, SpineCAMP, to those obtained by experienced operators using a legacy semi-automated method, QMA. Methods 120 lateral radiographs, evenly distributed across the cervical and lumbar spine regions with 30 flexion-extension exams per anatomical region, were collected from 49 different clinical sites and include preoperative and postoperative imaging. After excluding images with discrepant labeling (4/120, 3.3%), 66 cervical and 59 lumbar levels were analyzed. Each exam had segmental rotation and translation measured by five trained QMA analysts and SpineCAMP’s fully automated AI pipeline. Results SpineCAMP had consistent anatomy and image view with QMA in 96.7% of images. QMA and SpineCAMP demonstrated excellent agreement with vertebral landmark placement, (r2=0.9999, 0.9999 for cervical landmarks X and Y positions; r2=0.9996, 0.9997 for lumbar landmarks X and Y positions). Mean absolute errors between QMA and SpineCAMP for segmental rotation and translation were 0.16° and 0.09 mm in the cervical spine and 0.18° and 0.14 mm in the lumbar spine. Conclusion Spinal motion measures are commonly utilized to support clinical decisions. A fully automated, AI-driven technology can deliver strong agreement to validated analyst-driven technology, thereby offering clinicians a convenient solution for measuring spinal motion.

Study Design: Retrospective analyses of the center of rotation (COR) in asymptomatic volunteers and symptomatic patients. Objective: Document (i) level-specific COR position at radiographically normal levels in asymptomatic volunteers, (ii) preoperative COR abnormalities in symptomatic patients, and (iii) correlations between COR and other intervertebral motion metrics. Summary of Background Data: The COR has been discussed in many prior publications; however, our understanding of the normal position of the COR, the types and prevalence of COR abnormalities in patients, and the association between COR and other more common measures of intervertebral motion remains limited. Methods: Using automated, FDA-cleared software, we quantified COR and standard motion/alignment metrics from cervical flexion-extension radiographs of 341 asymptomatic volunteers and 1263 symptomatic preoperative patients. Level-specific 95% reference ellipses were derived from volunteers. Abnormality was defined as COR outside the level-matched ellipse. Associations between COR (cranial-caudal and anteroposterior) and rotation, translation, sagittal plane offset, disc height change, and standardized instability indices were evaluated. Results: In volunteers, COR was level-dependent and well summarized by 95% reference ellipses. The cranial-caudal position of COR was chiefly determined by rotation and translation, whereas the anteroposterior position related to sagittal plane offset and disc height change. COR also correlated with translational (TI-Index) and vertical (AVI/PVI) instability metrics. In symptomatic patients, most levels fell within reference ellipses; when deviations occurred, they were infrequent and multidirectional. Conclusions: COR can be automatically derived from flexion-extension radiographs. Deviations from level-specific reference ellipses provide an intuitive visualization of abnormal kinematics, complementing established motion metrics and linking cranial-caudal and anteroposterior shifts to specific patterns of translation, alignment, and instability.

Background:The concept of spinal instability has been the subject of research since the 1940s and is commonly used in clinical practice to decide on patient treatment. This is despite the lack of an adequately validated diagnostic test for instability. Our goal is to describe automated tests to detect segmental translational and vertical instabilities that can be obtained from lumbar flexion-extension radiographs. We also assess the prevalence of these instabilities in different patient populations. Methods:Using fully automated methods: (I) flexion-extension studies of asymptomatic volunteers were analyzed to understand the performance of instability metrics in that population; (II) 7,621 lumbar spine flexion-extension from multiple clinical studies were analyzed to document the prevalence of sagittal plane translational and vertical instabilities, corrected for the amount of intervertebral rotation, across different patient populations. Results:Translational or vertical motion abnormalities were rare (<4% of levels) in the asymptomatic population, and the magnitude of translational motion was associated with radiographic disc degeneration (P<0.0001). Sagittal plane translational instabilities were uncommon (<4% of treatment levels) in lumbar disc arthroplasty and biologic disc treatment patients. They were more common (11% to 16% of treatment levels) in lumbar stenosis, lumbar fusion, and dynamic stabilization patients. A higher prevalence of vertical instabilities (27% to 48% of treatment levels) was seen in patients treated for lumbar stenosis and those selected for fusion or dynamic stabilization than those enrolled in disc arthroplasty studies or studies investigating biologics for disc disease treatment (6% to 11% of treatment levels). Conclusions:New and fully automated approaches to detecting abnormal sagittal plane intervertebral motion may lead to enhanced and standardized diagnosis of lumbar spine instability. Further clinical research is imperative to verify prevalences and validate the efficacy of these metrics in diagnosis and treatment algorithms. If supported by additional research, these metrics may help determine, for example, which lumbar spinal stenosis patients require fusion in addition to decompression surgery.

Prospective, multicenter, single-blind, randomized, and controlled pivotal study. Compare time-to-fusion in patients treated with P-15L (PearlMatrix TM P-15 peptide enhanced bone graft) versus local autograft over 24 months and evaluate changes in pain and quality of life at 24 months relative to baseline. P-15L, an FDA-designated breakthrough device, is a composite bone graft with P-15, a 15-amino acid polypeptide that promotes cellular adhesion, proliferation, and differentiation to support bone formation. Patients (22–80 y) with degenerative disc disease were randomized to the investigational (P-15L) or control (local autograft) group during single-level transforaminal lumbar interbody fusion (TLIF) with a PEEK cage and supplemental pedicle screw fixation. Fusion assessments occurred at 6, 12, and 24 months. Time-to-fusion was tested for superiority as compared with the control using Kaplan-Meier survival analysis. Back and leg pain were measured using the Visual Analog Scale (VAS) and quality of life was assessed using the Short Form Survey (SF-12). The analysis included 290 patients from 33 sites; 141 (48.6%) received P-15L and 149 (51.3%) received local autograft. At randomization, at least one risk factor for pseudoarthrosis (obesity, nicotine use, or diabetes) was reported in 58.9% (83/141) of the investigational group and 60.4% (90/149) of the control group. More patients in the investigational group than the control group achieved fusion at 6 months (Kaplan-Meier fusion rates 57.6% vs. 26.9%, respectively), 12 months (68.8% vs. 41.5%, respectively), and 24 months (81.1% vs. 54.9%, respectively). P-15L was statistically superior to autograft for time-to-fusion (hazard ratio=1.87, 95% CI: 1.47–2.38; P < 0.0001). There was marked improvement in VAS and SF-12 relative to baseline in both groups at 24 months. P-15L promotes statistically superior earlier time-to-fusion than local autograft in instrumented TLIF. Both treatments resulted in clinically meaningful improvements in pain and quality of life at 24 months. Level I.

STUDY DESIGN:Prospective, multicenter, single-blind, randomized, controlled pivotal study. OBJECTIVE:To evaluate whether P-15L (PearlMatrix P-15 Peptide Enhanced Bone Graft) is noninferior in effectiveness to local autograft when applied in single-level instrumented transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA:P-15L, an FDA-designated Breakthrough Drug-Device, is a composite drug-device combination bone graft containing P-15, a 15-amino acid polypeptide, which enhances cell binding, proliferation, and differentiation, resulting in bone formation. MATERIALS AND METHODS:Skeletally mature patients, aged 22 to 80 years, with degenerative disc disease (DDD) were randomized 1:1 to P-15L (investigational) or to the local autograft (control) during single-level TLIF with a polyetheretherketone (PEEK) cage and supplemental pedicle screw fixation. The primary outcome was composite clinical success (CCS) at 24 months, defined as: no index level secondary surgical procedures; achievement of fusion; ≥15-point improvement in Oswestry low back pain disability questionnaire (ODI) from baseline; no new or worsening persistent neurological deficit relative to baseline; and no device-related serious adverse events (SAEs). RESULTS:A total of 290 patients were enrolled at 33 sites: 141 (48.6%) received P-15L, and 149 (51.3%) received local autograft. P-15L was noninferior ( P <0.0001) and superior ( P =0.002) to autograft with respect to CCS, with 55.5% of the investigational group achieving composite clinical success compared with 37.5% of the control group. P-15L had a 25.8% higher fusion rate as compared with autograft for the CCS at 24 months (84.3% vs. 58.5%, respectively). Device-related SAE rates were similar in both groups. CONCLUSION:P-15L was superior to local autograft in achieving clinical success at 24 months. Furthermore, P-15L produced a significantly higher fusion rate as compared with autograft. No meaningful clinical differences were found in the incidence of device-related SAEs. P-15L appears to be a safe and effective option for TLIF. LEVEL OF EVIDENCE:Level I.

This study aimed at comparing the costs of spinal fusion surgery between patients with and without diabetes. Following PRISMA guidelines, a systematic search of four databases was conducted. A meta-analysis was performed on comparative studies examining diabetic versus non-diabetic adults undergoing cervical/lumbar fusion in terms of cost. Heterogeneity was assessed using the I2 test. Standardized mean differences (SMD) and odds ratios (OR) with 95

Prospective, multicenter, single-blind, randomized, controlled pivotal study. To evaluate whether P-15L (PearlMatrix P-15 Peptide Enhanced Bone Graft) is noninferior in effectiveness to local autograft when applied in single-level instrumented transforaminal lumbar interbody fusion (TLIF). P-15L, an FDA-designated Breakthrough Drug-Device, is a composite drug-device combination bone graft containing P-15, a 15-amino acid polypeptide, which enhances cell binding, proliferation, and differentiation, resulting in bone formation. Skeletally mature patients, aged 22 to 80 years, with degenerative disc disease (DDD) were randomized 1:1 to P-15L (investigational) or to the local autograft (control) during single-level TLIF with a polyetheretherketone (PEEK) cage and supplemental pedicle screw fixation. The primary outcome was composite clinical success (CCS) at 24 months, defined as: no index level secondary surgical procedures; achievement of fusion; ≥15-point improvement in Oswestry low back pain disability questionnaire (ODI) from baseline; no new or worsening persistent neurological deficit relative to baseline; and no device-related serious adverse events (SAEs). A total of 290 patients were enrolled at 33 sites: 141 (48.6%) received P-15L, and 149 (51.3%) received local autograft. P-15L was noninferior ( P <0.0001) and superior ( P =0.002) to autograft with respect to CCS, with 55.5% of the investigational group achieving composite clinical success compared with 37.5% of the control group. P-15L had a 25.8% higher fusion rate as compared with autograft for the CCS at 24 months (84.3% vs. 58.5%, respectively). Device-related SAE rates were similar in both groups. P-15L was superior to local autograft in achieving clinical success at 24 months. Furthermore, P-15L produced a significantly higher fusion rate as compared with autograft. No meaningful clinical differences were found in the incidence of device-related SAEs. P-15L appears to be a safe and effective option for TLIF. Level I.

Study DesignSystematic review and meta-analysis.ObjectiveA systematic review and meta-analysis of comparative studies was performed to compare the fusion rates, functional outcomes, and complications between Titanium-Coated Polyetheretherketone (TiPEEK) and polyetheretherketone (PEEK) cages.MethodsFour databases were systematically searched according to PRISMA. Adult patients who underwent one- or two-level lumbar fusion with TiPEEK or PEEK cages were included in the study. Studies that reported radiographic fusion and functional or complication outcomes were also included. Study quality was assessed using the Cochrane Risk of Bias tool and MINORS criteria. The meta-analysis was performed using Review Manager 5.4. Heterogeneity was assessed using I2, and random effects were used to analyze the heterogeneity.Results8 studies (n = 670) were analyzed. TiPEEK showed a significantly higher overall fusion rate (OR 1.83, 95% CI: 1.18-2.83). TiPEEK cages presented significantly higher fusion rates at 6 months (OR 2.52, 95% CI: 1.11 to 5.72), but there were no significant differences at 12 months (OR 1.33, 95% CI: 0.65 to 2.73). No differences were observed in the global ODI (SMD -0.04, 95% CI: -0.15-0.06). There were no significant differences regarding overall subsidence (OR 0.72, 95% CI: 0.48 to 1.07), screw complications (OR 1.25, 95% CI: 0.30-5.27) or reoperations (OR 0.61, 95% CI: 0.11-3.37).ConclusionsThe results from this study suggest that TiPEEK cages may demonstrate earlier fusion as compared to PEEK cages, particularly at 6 months. However, the functional outcomes and safety profiles were comparable.

STUDY DESIGN:Systematic review and meta-analysis. PURPOSE:This meta-analysis aimed to provide a comprehensive evaluation of the impact of diabetes on spinal surgery outcomes. BACKGROUND:Diabetes mellitus is believed to be associated with an increased risk of adverse events during spinal surgery. With the increasing prevalence of diabetes and the increasing number of degenerative spinal procedures, understanding postsurgical expectations and optimal care is essential. MATERIALS AND METHODS:Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic search was conducted across PubMed, EMBASE, Scopus, and the Cochrane Library, selecting studies comparing diabetes and those without diabetes who underwent spine fusion surgeries. Eighteen studies with 118,617 patients were included. The outcomes of interest were the risk of the incidence of spinal pseudoarthrosis and PROMs, including Visual Analog Scale (VAS), Oswestry Disability Index (ODI), EQ-5D, and SF-12/36 score. Odds ratios (OR) were calculated for dichotomous variables, mean differences (MD) for continuous variables, and standard mean differences (SMD) for continuous variables not sharing the same scale or units. Random effects were used if there was evidence of statistical heterogeneity. RESULTS:Eighteen studies, comprising 118,617 patients, were included in the final analysis. Diabetes patients had a higher incidence of pseudoarthrosis at the lumbar spine (OR: 1.13, 95% CI: 1.02 to 1.25, P < 0.05). Patients with diabetes also reported increased VAS back/neck pain scores (SMD: 0.21, 95% CI: 0.14 to 0.28, P < 0.001) and worse ODI outcomes (MD: 3.96, 95% CI: 3.10 to 4.82, P < 0.001), EQ-5D (MD: -0.06, 95% CI: -0.08 to -0.03, P < 0.001) and SF-12/36 scores (SMD: -2.70, 95% CI: -4.99 to -0.41, P < 0.05). CONCLUSION:Patients with diabetes who underwent spinal surgery had a higher incidence of pseudoarthrosis and worse functional outcomes compared with nondiabetic patients. These findings underscore the need for targeted clinical management and preventive strategies for patients with diabetes undergoing these procedures. LEVEL OF EVIDENCE:Level III.

STUDY DESIGN:Systematic review and meta-analysis. PURPOSE:The objective of this study is to determine the impact of obesity on three key lumbar spinal surgery outcomes: the incidence of spinal nonunion, patient-reported outcome measures (PROMs), and the associated health care costs. SUMMARY OF BACKGROUND DATA:Obesity is a well-recognized risk factor in various medical fields, notably impacting outcomes in orthopedics and traumatology. While there is substantial documentation of the complications associated with obesity in general surgical procedures, the relationship between obesity and spinal surgery outcomes remains less clear. The inconsistency in the evidence presents a significant gap in our understanding of how obesity influences the results of spinal surgeries, particularly in terms of nonunion rates, patient-reported outcomes, and the associated health care costs. METHODS:A systematic search was conducted in PubMed, EMBASE, Scopus, and the Cochrane Library following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Studies comparing patients with or without obesity with lumbar spinal fusion were included. Comparative studies (cohort and case-control) were included. For dichotomous variables such as spinal nonunion, analysis was conducted using odds ratios (OR); for continuous variables such as PROMs [Oswestry Disability Index (ODI), Visual Analogue Scale (VAS), and 12/36-Item Short Form Survey (SF-12/36), and costs, analyses were performed using mean differences (MD) or standardized mean differences (SMD)]. RESULTS:Fifteen studies with a pool of 61341 patients were included. Obesity (BMI≥30) was significantly associated with a higher nonunion frequency (OR 2.10, 95% CI: 1.23-3.60, P <0.01). The ODI was significantly worse in the obesity group (MD 6.29, 95% CI: 4.71-7.88, P <0.001). Greater pain was measured by the VAS back pain (MD 0.95, 95% CI: 0.17-1.73, P <0.05) and VAS leg pain (MD 0.94, 95% CI: 0.68-1.20, P <0.001) scales for lumbar surgery patients with obesity. The SF-12/36 showed significantly worse outcomes in patients with obesity (SMD -0.46, 95% CI: -0.82 to -0.09, P =0.01). Hospitalization costs were significantly higher in patients with obesity (SMD 0.09, 95% CI: 0.05-0.12, P <0.001). CONCLUSIONS:This meta-analysis suggests that obesity is significantly associated with higher nonunion rates, poorer patient-reported outcome measures, including Oswestry Disability Index, Visual Analogue Scale, and 36-Item Short Form Survey, and higher hospitalization costs following lumbar spinal fusion. LEVEL OF EVIDENCE:Level III.

STUDY DESIGN:Prospective, multicenter, single-blind, randomized, and controlled pivotal study. OBJECTIVE:Compare time-to-fusion in patients treated with P-15L (PearlMatrix TM P-15 peptide enhanced bone graft) versus local autograft over 24 months and evaluate changes in pain and quality of life at 24 months relative to baseline. SUMMARY OF BACKGROUND DATA:P-15L, an FDA-designated breakthrough device, is a composite bone graft with P-15, a 15-amino acid polypeptide that promotes cellular adhesion, proliferation, and differentiation to support bone formation. METHODS:Patients (22-80 y) with degenerative disc disease were randomized to the investigational (P-15L) or control (local autograft) group during single-level transforaminal lumbar interbody fusion (TLIF) with a PEEK cage and supplemental pedicle screw fixation. Fusion assessments occurred at 6, 12, and 24 months. Time-to-fusion was tested for superiority as compared with the control using Kaplan-Meier survival analysis. Back and leg pain were measured using the Visual Analog Scale (VAS) and quality of life was assessed using the Short Form Survey (SF-12). RESULTS:The analysis included 290 patients from 33 sites; 141 (48.6%) received P-15L and 149 (51.3%) received local autograft. At randomization, at least one risk factor for pseudoarthrosis (obesity, nicotine use, or diabetes) was reported in 58.9% (83/141) of the investigational group and 60.4% (90/149) of the control group. More patients in the investigational group than the control group achieved fusion at 6 months (Kaplan-Meier fusion rates 57.6% vs. 26.9%, respectively), 12 months (68.8% vs. 41.5%, respectively), and 24 months (81.1% vs. 54.9%, respectively). P-15L was statistically superior to autograft for time-to-fusion (hazard ratio=1.87, 95% CI: 1.47-2.38; P  < 0.0001). There was marked improvement in VAS and SF-12 relative to baseline in both groups at 24 months. CONCLUSION:P-15L promotes statistically superior earlier time-to-fusion than local autograft in instrumented TLIF. Both treatments resulted in clinically meaningful improvements in pain and quality of life at 24 months. LEVEL OF EVIDENCE:Level I.

BACKGROUND CONTEXT:Failure to fuse following anterior cervical discectomy and fusion (ACDF) may result in symptomatic pseudoarthrosis. Traditional diagnosis involves computerized tomography to detect bridging bone and/or flexion-extension radiographs to assess whether segmental motion is above specific thresholds; however, there are currently no well-validated diagnostic tests. We propose a biomechanically rational approach to achieve a reliable diagnostic test for pseudoarthrosis. PURPOSE:Develop and test a biomechanically based approach to the diagnosis of pseudoarthrosis. STUDY DESIGN:Literature review, development of theory, reanalysis of a previously published study with surgical exploration as the gold-standard, and retrospective analysis of pooled studies to understand time to fusion. METHODS:Fully automated methods were used to measure disc space strains (change in disc space height divided by initial height). Measurement error combined with the reported failure strain of trabecular bone led to a proposed strain threshold for diagnosis of pseudoarthrosis following ACDF. We reanalyzed previously reported flexion-extension radiographs for asymptomatic volunteers to assess whether flexion-extension radiographs, in the absence of fusion surgery, can be expected to provide sufficient stress on motion segments to allow for reliable strain-based fusion assessment. The sensitivity and specificity of strain- and rotation-based pseudoarthrosis diagnosis were assessed by reanalysis of previously reported post-ACDF flexion-extension radiographs, where intraoperative fusion assessments were also available. Finally, we assessed changes in strain over time using 9,869 flexion-extension radiographs obtained 6 weeks to 84 months post-ACDF surgery from 1,369 patients. RESULTS:The estimated error in automated measurement of disc space strain from radiographs was approximately 3%, and the reported failure strain of bridging bone was less than 2.5%. On that basis, we propose a 5% strain threshold for pseudoarthrosis diagnosis. Reanalysis of a study in which intraoperative fusion assessments were available revealed 67% sensitivity and 82% specificity for strain-based diagnosis of pseudoarthrosis, which was comparable to rotation-based diagnosis. Analysis of post-ACDF flexion-extension radiographs revealed rapid strain reduction for up to 24 months, followed by a slower decrease for up to 84 months. When rotation is less than 2°, the strain-based diagnosis differed from the rotation-based diagnosis in approximately 14% of the cases. CONCLUSIONS:We propose steps for standardizing diagnosis of pseudoarthrosis based on the failure strain of bone, measurement error, and retrospective data. These steps include obtaining high-quality flexion-extension studies, the application of proposed diagnostic thresholds, and the use of image stabilization for conclusive diagnosis, when motion is near thresholds. The necessity for an accurate diagnosis with minimal radiation exposure underscores the need for further optimization and standardization in diagnosing pseudoarthrosis following ACDF surgery. CLINICAL SIGNIFICANCE:In a symptomatic postspine fusion patient, it is important to diagnose or rule-out pseudoarthrosis. There are currently no well-validated diagnostic tests for this condition. Incorporating strain-based intervertebral motion analysis into the diagnosis could lead to a standardized and validated test for detecting spine pseudoarthrosis.

IntroductionRetained shrapnel from gunshots is a common occurrence; however, retained shrapnel within the spinal canal is exceedingly uncommon. Guidelines for removal and treatment of these cases are a difficult topic, as surgical removal is not necessarily without consequence, and retention can lead to possible further injury or a secondary disease process of plumbism, which can be difficult to diagnose in this population.Case presentationThis case report provides a unique example of a young patient with retained shrapnel from a gunshot. This patient suffered an initial spinal cord injury due to a gunshot and secondarily presented with abdominal pain, fatigue, elevated blood lead levels, and was diagnosed with plumbism. This was addressed with operative removal of shrapnel and posterior instrumented spinal fusion, resulting in decreased lead levels and symptom resolution postoperatively.DiscussionLead toxicity risk in patients with retained shrapnel, particularly in the spine, warrants vigilant monitoring. While management guidelines lack consensus, symptomatic lead toxicity may necessitate intervention. Residual neurological deficits complicate evaluation, emphasizing individualized management decisions.

Study Design. Retrospective cohort. Objective. Examine the relationship between compensatory pelvic retroversion, positive sagittal imbalance (measured by C2 tilt), and the C2 pelvic angle (C2PA) in patients before long spinal fusions; and to determine the association between changes in C2PA and pelvic tilt (PT) following long spinal fusions. Background. Adult spinal deformity surgical goals often include a PT target, yet patients frequently demonstrate persistent compensatory pelvic retroversion following surgery. Methods. Adults above 18 years old undergoing long spinal fusions (>4 levels) with standing preoperative and postoperative radiographs were included. To examine drivers of preoperative sagittal balance, regression models were fit to estimate the association between preoperative C2PA and pelvic incidence with preoperative PT and C2 tilt. To predict postoperative change in PT, multivariable regression was used to estimate change in PT, adjusting for change in C2PA and preoperative C2 tilt. Results. Among the 80 patients identified, the median age was 61 (IQR: 45-72) and 46 (58%) were female. The median number of levels fused was 10 (IQR: 8-13) and 55 (69%) were instrumented to the sacrum/pelvis. Preoperative C2PA had a significant nonlinear association with preoperative PT (r(2)=0.81, P<0.001) and preoperative C2 tilt (r(2)=0.41, P=0.002). Postoperative change in PT was strongly associated with change in C2PA (beta=0.81; P<0.001) and preoperative C2 tilt (beta=0.55; P<0.001). Conclusions. Following long spinal fusions, change in PT (or lack thereof) can be reliably predicted based on change in C2PA and preoperative C2 tilt. In patients with normal preoperative C2 tilt, the change in C2PA is nearly equivalent to the change in PT, but in patients with more positive C2 tilt (sagittal imbalance), a greater change in C2PA will be required to achieve an equivalent change in PT. Level of Evidence.3.

Study Design Retrospective Cohort Study. Objective The aim of this study was to compare the efficacy of CT-based computer assisted navigation (CAN) to conventional pedicle screw placement for patients with Adolescent Idiopathic Scoliosis (AIS). Methods This retrospective cohort study drew data from the National Readmissions Database, years 2016-2019. Patients undergoing posterior fusion for AIS, either via CAN or fluoroscopic-guided procedures, were identified via ICD-10 codes. Multivariate regression was performed to compare outcomes between operative techniques. Negative binomial regression was used to asses discharge disposition, while Gamma regression was performed to assess length of stay (LOS) and total charges. Patient demographics and comorbidities, measured via the Elixhauser comorbidity index, were both controlled for in our regression analysis. Results 28,868 patients, 2095 (7.3%) undergoing a CAN procedure, were included in our analysis. Patients undergoing CAN procedures had increased surgical complications (Odds Ratio (OR) 2.23; P < 0.001), namely, blood transfusions (OR 2.47; P < 0.001). Discharge disposition and LOS were similar, as were reoperation and readmission rates; however, total charges were significantly greater in the CAN group (OR 1.37; P < 0.001). Mean charges were 191,489.42 (119,302.30) USD for conventional surgery vs 268 589.86 (105,636.78) USD for the CAN cohort. Conclusion CAN in posterior fusion for AIS does not appear to decrease postoperative complications and is associated with an increased need for blood transfusions. Given the much higher total cost of care that was also seen with CAN, this study calls into question whether the use of CAN is justified in this setting.

Background:Traditional pedicle screws (TPSs) and cortical based trajectory pedicle screws each apply stability with fusions of the lumbar spine and have shown good success. However, the technical considerations of each technique imply complications of loosening and failure that either technique is uniquely prone to having. The current study proposes a new pedicle screw technique through the articular surface of the vertebral superior facet. It is hypothesized that this path will allow utilization of a larger screw that rivals that of the TPS technique, while also maintaining the high-density bone encountered in the cortical based trajectory technique.Methods:Retrospective review of 50 consecutive trauma patients that underwent lumbar computed tomography (CT) scans at a Level 1 Trauma Center in the age range 18-45. These scans were uploaded to Brainlab software for ideal starting point and trajectory mapping of pedicle screws coursing through each superior facet and pedicle of vertebral levels L1-S1 without cortical breach. Satisfactory pedicle screw variables consisted of a medial angle <10 degrees, screw length at least 30 mm, screw width at least 5.0 mm, and starting point measurements such as distance to the inferior articular surface and distance to the lateral articular surface.Results:A total of 600 virtual pedicle screws were placed, in which 525 were satisfactory and measured with the above variables. The pedicle widths were shown to significantly widen with lower-level vertebra in the lumbar spine. Approximately 72% of unsuccessful pedicle screws were placed in levels L1 and L2 allowing wider pedicle screws to be placed more further down the vertebral column.Conclusions:The articular surface technique (AST) for pedicle screw placement is a viable alternative in lumbar spinal fusions that offers decreased soft tissue dissection. However, the technique is likely better suited for lower lumbar fusions in L3 to S1.