Pedicle screw placement in the cervical vertebrae using augmented reality-head mounted displays: a cadaveric proof-of-concept study.

BACKGROUND: The accurate and safe positioning of cervical pedicle screws is crucial. While augmented reality (AR) use in spine surgery has previously demonstrated clinical utility in the thoracolumbar spine, its technical feasibility in the cervical spine remains less explored. PURPOSE: The objective of this study was to assess the precision and safety of AR-assisted pedicle screw placement in the cervical spine. STUDY DESIGN: In this experimental study, five cadaveric cervical spine models were instrumented from C3 to C7 by five different spine surgeons. The navigation accuracy and clinical screw accuracy were evaluated. METHODS: Post-procedural CT scans were evaluated for clinical accuracy by two independent neuroradiologists using the Gertzbein-Robbins scale. Technical precision was assessed by calculating the angular trajectory (°) and linear screw tip (mm) deviations in the axial and sagittal planes from the virtual pedicle screw position as recorded by the AR-guided platform during the procedure compared to the actual pedicle screw position derived from post-procedural imaging. RESULTS: A total of forty-one pedicle screws were placed in five cervical cadavers, with each of the five surgeons navigating at least seven screws. Gertzbein-Robbins grade of A or B was achieved in 100% of cases. The mean values for tip and trajectory errors in the axial and sagittal planes between the virtual versus actual position of the screws was less than 3 mm and 30°, respectively (p<0.05). None of the cervical screws violated the cortex by more than 2 mm or displaced neurovascular structures. CONCLUSIONS: AR-assisted cervical pedicle screw placement in cadavers demonstrated clinical accuracy comparable to existing literature values for image-guided navigation methods for the cervical spine. CLINICAL SIGNIFICANCE: This study provides technical and clinical accuracy data that supports clinical trialing of AR-assisted subaxial cervical pedicle screw placement.

A Meta-Analysis of Surgical Outcomes in 25727 Patients Undergoing Anterior Cervical Discectomy and Fusion or Anterior Cervical Corpectomy and Fusion for Cervical Deformity.

STUDY DESIGN: Systematic Review. OBJECTIVES: To evaluate which cervical deformity correction technique between anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) produces better clinical, radiographic, and operative outcomes. METHODS: We conducted a meta-analysis comparing studies involving ACDF and ACCF. Adult patients with either original or previously treated cervical spine deformities were included. Two independent reviewers categorized extracted data into clinical, radiographic, and operative outcomes, including complications. Clinical assessments included patient-reported outcomes; radiographic evaluations examined C2-C7 Cobb angle, T1 slope, T1-CL, C2-7 SVA, and graft stability. Surgical measures included surgery duration, blood loss, hospital stay, and complications. RESULTS: 26 studies (25727 patients) met inclusion criteria and were extracted. Of these, 14 studies (19077 patients) with low risk of bias were included in meta-analysis. ACDF and ACCF similarly improve clinical outcomes in terms of JOA and NDI, but ACDF is significantly better at achieving lower VAS neck scores. ACDF is also more advantageous for improving cervical lordosis and minimizing the incidence of graft complications. While there is no significant difference between approaches for most surgical complications, ACDF is favorable for reducing operative time, intraoperative blood loss, and length of hospital stay. CONCLUSIONS: While both techniques benefit cervical deformity patients, when both techniques are feasible, ACDF may be superior with respect to VAS neck scores, cervical lordosis, graft complications and certain perioperative outcomes. Further studies are recommended to address outcome variability and refine surgical approach selection.

Pelvic Incidence-Lumbar Lordosis Mismatch is Not Associated with Early Reoperation for Adjacent Segment Disease after Lumbar Fusion.

STUDY DESIGN: Retrospective Cohort Study OBJECTIVES: To compare the 2-year reoperation rates for adjacent segment disease between patients with pelvic incidence-lumbar lordosis (PI-LL) mismatch postoperatively and patients with normal PI-LL measurements. METHODS: Patients undergoing elective 1-to-2 level lumbar fusion for degenerative conditions between 2016-2018 were retrospectively reviewed. Spinopelvic radiographic parameters immediately post-operation were measured and PI-LL mismatch was determined using the age-adjusted thresholds defined in Lafage et al. Following propensity score matching, early reoperation rates were compared between the PI-LL mismatch and normal PI-LL cohorts. Early reoperation was defined as symptomatic adjacent segment disease (ASD) requiring reoperation within 2 years of the index surgery. RESULTS: A total of 219 patients were identified. The average age was 59 years old with 59.8% female. The PI-LL mismatch cohort (N=148) were younger (57.5 vs. 63.5, p<0.001) and had a higher proportion of black patients (31.8% vs. 11.3%, p=0.001) compared to the normal PI-LL cohort. A total of 100 patients in the PI-LL mismatch cohort were propensity score matched to 66 patients in the normal PI-LL cohort, resulting in no difference in age (p=0.177), sex (p=0.302), race (p=0.727), or BMI (p=0.892). Using these matched cohorts, the rate of early reoperation for ASD was 8.0 % in the PI-LL mismatch cohort and 9.1% in the normal PI-LL cohort (p=0.805) with a mean time to reoperation of 1.28 and 1.33 years, respectively. CONCLUSIONS: After propensity score matching, PI-LL mismatch was not associated with early reoperation for ASD in patients undergoing 1-to-2 level lumbar fusions for degenerative conditions.

The changing epidemiology of traumatic spine injuries: a trends analysis of 26 years of patients at a major level 1 trauma center in the United States.

BACKGROUND CONTEXT: Traumatic spinal injuries (TSI) are associated with high morbidity, mortality, and resource utilization. The epidemiology of TSI varies greatly across different countries and regions and is impacted by national income levels, infrastructure, and cultural factors. Further, there may be changes over time. It is essential to investigate TSI to gain useful epidemiologic information. However, there have been no recent studies on trends for TSI in the US, despite the changing population demographics, healthcare policy, and technology. As a result, reexamination is warranted to reflect how the modern era has affected the epidemiology of US spine trauma patients and their management. PURPOSE: To determine epidemiologic trends in traumatic spine injuries over time. STUDY DESIGN/SETTING: Retrospective analysis; level 1 trauma center in the United States. PATIENT SAMPLE: A total of 21,811 patients, between the years of 1996 and 2022, who presented with traumatic spine injury. OUTCOME MEASURES: Age, sex, race, Injury Severity Score, mechanism of injury, injury diagnosis, injury level, rate of operative intervention, hospital length of stay, intensive care unit length of stay, discharge disposition, in-hospital mortality. METHODS: Data was collected from our institutional trauma registry over a 26-year period. Inclusion criteria involved at least one diagnosis of vertebral fracture, spinal cord injury, spinal subluxation, or intervertebral disc injury. Exclusion criteria consisted of patients with no diagnosed spine injury or a diagnosis of strain only. A total of 21,811 patients were included in the analysis. Descriptive statistics were tabulated and ordinary least squares linear regression was conducted for trends analysis. RESULTS: Regression analysis showed a significant upward trend in patient age (+13.83 years, ß=+0.65/year, p<.001), female sex (+2.7%, ß=+0.18%/year, p=.004), falls (+10.5%, ß=+0.82%/year, p<.001), subluxations (+12.8%, ß=+0.35%/year, p<.001), thoracic injuries (+1.5%, ß=+0.28%/year, p<.001), and discharges to subacute rehab (+15.9%, ß=+0.68%/year, p<.001). There was a significant downward trend in motor vehicle crashes (-7.8%, ß=-0.47%/year, p=.016), firearms injuries (-3.4%, ß=-0.19%/year, p<.001), sports/recreation injuries (-2.9%, ß=-0.18%/year, p<.001), spinal cord injuries (-11.25%, ß=-0.37%, p<.001), complete spinal cord injuries (-7.6%, ß=-0.24%/year, p<.001), and discharges to home (+4.5%, ß=-0.27%/year, p=.011). CONCLUSIONS: At our institution, the average spine trauma patient has trended toward older females. Falls represent an increasing proportion of the mechanism of injury, on a trajectory to become the most common cause. With time, there have been fewer spinal cord injuries and a lower proportion of complete injuries. At discharge, there has been a surge in the utilization of subacute rehabilitation facilities. Overall, there has been no significant change in injury severity, rate of operative intervention, length of stay, or mortality.

Diagnosis and Management of Thoracic Myelopathy.

Thoracic myelopathy can be a challenging condition to diagnose and treat. Successful outcomes depend on early recondition of the pathology and appropriate surgical referral in cases of progressive neurologic deterioration. The thoracic cord is tethered in kyphosis by the dentate ligaments and contains a tenuous blood supply. These conditions make the thoracic cord particularly susceptible to external compression and ischemic damage. Careful preoperative planning with specific attention to the location and source of thoracic stenosis is critical to successful decompression and complication avoidance. The purpose of this discussion is to outline the common sources of thoracic myelopathy and current recommendations regarding diagnosis and management. The review concludes with an overview of the most up-to-date literature regarding clinical outcomes.

Superinfections of the Spine: A Single-Institution Experience.

Background/Objectives: A superinfection occurs when a new, secondary organism colonizes an existing infection. Spine infections are associated with high patient morbidity and sometimes require multiple irrigations and debridements (I&Ds). When multiple I&Ds are required, the risk of complications increases. The purpose of this study was to report our experience with spine superinfections and determine which patients are typically affected. Methods: A retrospective case series of spine superinfections and a retrospective case-control analysis were conducted. Data were collected manually from electronic medical records. Spine I&Ds were identified. Groups were created for patients who had multiple I&Ds for (1) a recurrence of the same causative organism or (2) a superinfection with a novel organism. Preoperative demographic, clinical, and microbiologic data were compared between these two outcomes. A case series of superinfections with descriptive data was constructed. Lastly, two illustrative cases were provided in a narrative format. Results: A total of 92 patients were included in this analysis. Superinfections occurred after 6 out of the 92 (7%) initial I&Ds and were responsible for 6 out of the 24 (25%) repeat I&Ds. The preoperative erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) of the patients with a superinfection were significantly lower than those in the control group (p = 0.022 and p = 0.032). Otherwise, the observed differences in the preoperative variables were not statistically different. In the six cases of superinfection, the presence of high-risk comorbidities, a history of substance abuse, or a lack of social support were commonly observed. The superinfecting organisms included Candida, Pseudomonas, Serratia, Klebsiella, Enterobacter, and Staphylococcus species. Conclusions: Superinfections are a devastating complication requiring reoperation after initial spine I&D. Awareness of the possibility of superinfection and common patient archetypes can be helpful for clinicians and care teams. Future work is needed to examine how to identify, help predict, and prevent spine superinfections.

Posterior Transdural Approach for Thoracic Corpectomies in the Setting of Complex Spine Deformity Reconstruction.

BACKGROUND AND OBJECTIVE: There are many surgical approaches for execution of a thoracic corpectomy. In cases of challenging deformity, traditional posterior approaches might not be sufficient to complete the resection of the vertebral body. In this technical note, we describe indications and technique for a transdural multilevel high thoracic corpectomy. METHODS: A 25-year-old man with a history of neurofibromatosis type 1 presented with instrumentation failure after a previous T1-T12 posterior spinal fusion, extensive laminectomy, and tumor resection. The patient presented with progressive back pain, had broad dural ectasia, and a progressive kyphotic rotational and anteriorly translated spinal deformity. To resect the medial-most aspect of the vertebral body, a bilateral extracavitary approach was attempted, but was found insufficient. A transdural approach was subsequently performed. A left paramedian durotomy was made, followed by generous arachnoid dissection, bilateral dentate ligament division, and T4 rootlet sacrifice to mobilize the spinal cord. A ventral durotomy was then made and the ventral dura was reflected over the spinal cord to protect it while drilling. The corpectomy was then completed. The ventral and dorsal durotomies were closed primarily and reinforced with fibrin glue and fibrin sealant patch. The corpectomy defect was filled with nonstructural autograft. RESULTS: The focal kyphosis was corrected with a combination of rod contouring, compression, and in situ bending. During the surgery, the patient had stable neuromonitoring data, and postoperatively had no neurological deficits. On follow-up until 1 year, the patient presented with no signs of cerebrospinal spinal leaks, no motor or sensory deficits, minimal incisional pain, and significantly improved posture. CONCLUSION: Complex high thoracic (T3-5) ventral pathology inaccessible via a bilateral extracavitary approach may be accessed via a transdural approach as opposed to an anterior/lateral transthoracic approach that requires mobilization of cardiovascular structures or scapula.

Utilization of Augmented Reality Head-Mounted Display for the Surgical Management of Thoracolumbar Spinal Trauma.

Background and Objectives: Augmented reality head-mounted display (AR-HMD) is a novel technology that provides surgeons with a real-time CT-guided 3-dimensional recapitulation of a patient's spinal anatomy. In this case series, we explore the use of AR-HMD alongside more traditional robotic assistance in surgical spine trauma cases to determine their effect on operative costs and perioperative outcomes. Materials and Methods: We retrospectively reviewed trauma patients who underwent pedicle screw placement surgery guided by AR-HMD or robotic-assisted platforms at an academic tertiary care center between 1 January 2021 and 31 December 2022. Outcome distributions were compared using the Mann-Whitney U test. Results: The AR cohort (n = 9) had a mean age of 66 years, BMI of 29.4 kg/m2, Charlson Comorbidity Index (CCI) of 4.1, and Surgical Invasiveness Index (SII) of 8.8. In total, 77 pedicle screws were placed in this cohort. Intra-operatively, there was a mean blood loss of 378 mL, 0.78 units transfused, 398 min spent in the operating room, and a 20-day LOS. The robotic cohort (n = 13) had a mean age of 56 years, BMI of 27.1 kg/m2, CCI of 3.8, and SII of 14.2. In total, 128 pedicle screws were placed in this cohort. Intra-operatively, there was a mean blood loss of 432 mL, 0.46 units transfused units used, 331 min spent in the operating room, and a 10.4-day LOS. No significant difference was found between the two cohorts in any outcome metrics. Conclusions: Although the need to address urgent spinal conditions poses a significant challenge to the implementation of innovative technologies in spine surgery, this study represents an initial effort to show that AR-HMD can yield comparable outcomes to traditional robotic surgical techniques. Moreover, it highlights the potential for AR-HMD to be readily integrated into Level 1 trauma centers without requiring extensive modifications or adjustments.

The Utility of the Validated Intraoperative Bleeding Scale in Thoracolumbar Spine Surgery: A Single-Center Prospective Study.

STUDY DESIGN: Prospective, single-center study. OBJECTIVE: To evaluate the clinical relevance of the validated intraoperative bleeding severity scale (VIBe) in thoracolumbar spine surgery. METHODS: Adult patients aged 18 through 88 undergoing elective decompression, instrumentation, and fusion of the thoracolumbar spine were prospectively enrolled after informed consent was provided and written consent was obtained. Validated intraoperative bleeding severity scores were recorded intraoperatively. Univariate analysis consisted of Student T-tests, Pearson's χ2 Tests, Fisher's Exact Tests, linear regression, and binary logistic regression. Multivariable regression was conducted to adjust for baseline characteristics and potential confounding variables. RESULTS: A total of N = 121 patients were enrolled and included in the analysis. After adjusting for confounders, VIBe scores were correlated with an increased likelihood of intraoperative blood transfusion (ß = 2.46, P = .012), postoperative blood transfusion (ß = 2.36, P = .015), any transfusion (ß = 2.49, P < .001), total transfusion volume (ß = 180.8, P = .020), and estimated blood loss (EBL) (ß = 409, P < .001). Validated intraoperative bleeding severity scores had no significant association with length of hospital stay, 30-day readmission, 30-day reoperation, 30-day emergency department visit, change in pre- to post-op hemoglobin and hematocrit, total drain output, or length of surgery. CONCLUSION: The VIBe scale is associated with perioperative transfusion rates and EBL in patients undergoing thoracolumbar spine surgery. Overall, the VIBe scale has clinically relevant meaning in spine surgery, and shows potential utility in clinical research. LEVEL OF EVIDENCE: Level II.