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.
OBJECTIVE: The objective of this study was to assess the precision and safety of AR-assisted pedicle screw placement in the cervical spine.
METHODS: In this experimental study, 5 cadaveric cervical spine models were instrumented from C3 to C7 by 5 different spine surgeons. The navigation accuracy and clinical screw accuracy were evaluated.
METHODS: Postprocedural CT scans were evaluated for clinical accuracy by 2 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 postprocedural imaging.
RESULTS: A total of forty-one pedicle screws were placed in 5 cervical cadavers, with each of the 5 surgeons navigating at least 7 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<.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.
CONCLUSIONS: This study provides technical and clinical accuracy data that supports clinical trialing of AR-assisted subaxial cervical pedicle screw placement.

Background: Anterior lumbar interbody fusion (ALIF) and posterior spinal fusion (PSF) play pivotal roles in restoring lumbar lordosis in spinal surgery. There is an ongoing debate between combined single-position surgery and traditional prone-position PSF for optimizing segmental lumbar lordosis. Methods: This retrospective study analyzed 59 patients who underwent ALIF in the supine position followed by PSF in the prone position at a single institution. Cobb angles were measured preoperatively, post-ALIF, and post-PSF using X-ray imaging. One-way repeated measures ANOVA and post-hoc analyses with Bonferroni adjustment were employed to compare mean Cobb angles at different time points. Cohen\'s d effect sizes were calculated to assess the magnitude of changes. Sample size calculations were performed to ensure statistical power. Results: The mean segmental Cobb angle significantly increased from preoperative (32.2 ± 13.8 degrees) to post-ALIF (42.2 ± 14.3 degrees, Cohen\'s d: -0.71, p < 0.0001) and post-PSF (43.6 ± 14.6 degrees, Cohen\'s d: -0.80, p < 0.0001). There was no significant difference between Cobb angles after ALIF and after PSF (Cohen\'s d: -0.10, p = 0.14). The findings remained consistent when Cobb angles were analyzed separately for single-screw and double-screw ALIF constructs. Conclusions: Both supine ALIF and prone PSF significantly increased segmental lumbar lordosis compared to preoperative measurements. The negligible difference between post-ALIF and post-PSF lordosis suggests that supine ALIF followed by prone PSF can be an effective approach, providing flexibility in surgical positioning without compromising lordosis improvement.

UNASSIGNED: Previous research has demonstrated that mid- to long-term health-related quality of life following corrective fusion surgery for adult spinal deformity (ASD) can be improved by appropriate revision surgery. In this study, we aim to compare the cost-effectiveness of corrective fusion surgery for ASD with and without unexpected revision surgery 5 years postoperatively.
UNASSIGNED: In total, 79 patients with ASD (mean age, 68.7 years) who underwent corrective fusion surgery between 2013 and 2015 were included in this study. Cost-effectiveness was evaluated based on the cost of obtaining 1 quality-adjusted life year (QALY). Patients were divided into two groups according to the presence or absence of unexpected revision surgery following corrective fusion and were subjected for comparison.
UNASSIGNED: As per our study findings, 26 (33%) of the 79 ASD patients underwent unexpected revision surgery during the first 5 years following surgery. Although there was no significant difference in terms of inpatient medical costs at the time of initial surgery for 5 years after surgery between the two groups (no-revision group, revision group; inpatient medical costs at the time of initial surgery: USD 69,854 vs. USD 72,685, P=0.344), the total medical expenses up to 5 years after surgery were found to be higher in the revision group (USD 72,704 vs. USD 104,287, P<0.001). The medical expenses required to improve 1 QALY 5 years after surgery were USD 178,476 in the no-revision group, whereas it was USD 222,081 in the revision group.
UNASSIGNED: Although the total medical expenses were higher in the revision group, no significant difference was observed in the cumulative QALY improvement between the revision and no-revision groups. Moreover, the medical expenses required to improve 1 QALY were higher in the revision group, with a difference of approximately 20%.

METHODS: Prospective multicenter database post-hoc analysis.
OBJECTIVE: Opioids are frequently prescribed for painful spinal conditions to provide pain relief and to allow for functional improvement, both before and after spine surgery. Amidst a current opioid epidemic, it is important for providers to understand the impact of opioid use and its relationship with patient-reported outcomes. The purpose of this study was to evaluate pre-/postoperative opioid consumption surrounding ASD and assess patient-reported pain outcomes in older patients undergoing surgery for spinal deformity.
METHODS: Patients ≥60 years of age from 12 international centers undergoing spinal fusion of at least 5 levels and a minimum 2-year follow-up were included. Patient-reported outcome scores were collected using the Numeric Rating Scale for back and leg pain (NRS-B; NRS-L) at baseline and at 2 years following surgery. Opioid use, defined based on a specific question on case report forms and question 11 from the SRS-22r questionnaire, was assessed at baseline and at 2-year follow-up.
RESULTS: Of the 219 patients who met inclusion criteria, 179 (81.7%) had 2-year data on opioid use. The percentages of patients reporting opioid use at baseline (n = 75, 34.2%) and 2 years after surgery (n = 55, 30.7%) were similar (P = .23). However, at last follow-up 39% of baseline opioid users (Opi) were no longer taking opioids, while 14% of initial non-users (No-Opi) reported opioid use. Regional pre- and postoperative opioid use was 5.8% and 7.7% in the Asian population, 58.3% and 53.1% in the European, and 50.5% and 40.2% in North American patients, respectively. Baseline opioid users reported more preoperative back pain than the No-Opi group (7.0 vs 5.7, P = .001), while NRS-Leg pain scores were comparable (4.8 vs 4, P = .159). Similarly, at last follow-up, patients in the Opi group had greater NRS-B scores than Non-Opi patients (3.2 vs 2.3, P = .012), but no differences in NRS-Leg pain scores (2.2 vs 2.4, P = .632) were observed.
CONCLUSIONS: In this study, almost one-third of surgical ASD patients were consuming opioids both pre- and postoperatively world-wide. There were marked international variations, with patients from Asia having a much lower usage rate, suggesting a cultural influence. Despite both opioid users and nonusers benefitting from surgery, preoperative opioid use was strongly associated with significantly more back pain at baseline that persisted at 2-year follow up, as well as persistent postoperative opioid needs.

UNASSIGNED: Spinal fusion surgery with instrumentation is a treatment of choice for many spinal disorders; however, there is little data related to factors associated with early and late outcomes, especially among patients with poor bone quality (e.g., osteoporosis). We conducted this study to characterize the epidemiology and outcomes of patients undergoing spinal fusion surgery with instrumentation in Japan, especially in patients with poor bone quality and those needing additional fixation methods.
UNASSIGNED: This retrospective observational study used real-world health insurance claims data from the Japanese Medical Data Vision. Adult patients undergoing an index spinal fusion procedure from April 1, 2010, to September 30, 2017, with procedural details, length of stay (LOS), total in-hospital costs, spine-related reoperation, all-cause readmission, and postoperative complications recorded. Data were summarized descriptively overall, by osteoporosis status, and additional fixation method used, and were analyzed in bivariate analyses. Multivariate logistic and linear regressions were used to explore associations between covariates and variables of interest.
UNASSIGNED: A total of 22,932 patients (mean age, 67.3 years; 51.2% male) met the study criteria and were included. A total of 5,288 (23.0%) patients had osteoporosis, and 2,507 (10.9%) needed additional fixation methods; these patients were older, more frequently female, and had higher Elixhauser comorbidity index scores. Osteoporosis and additional fixation use were also associated with longer LOS, higher hospital costs, and higher rates of complications.
UNASSIGNED: Patients with osteoporosis and those needing additional fixation methods have a higher risk for procedural and postoperative complications, reoperation, longer LOS, and higher total hospital costs.

Background Many studies have been conducted on the biomechanics of the spine to elucidate the fixation properties of spinal fusion surgery and the causes of instrumentation failure. Among these studies, there are some studies on load sharing in the spine and measurement using strain gauges and pressure gauges, but there is a lack of research on axial compressive loads. Methods Axial compressive load tests were performed on human cadaveric injured lumbar vertebrae fixed with pedicle screws (PS). Both the strain generated in the PS rod and the intradiscal pressure were measured. Subsequently, the stress generated in the PS rod and the load sharing of the spine and instrumentation were calculated. Results Even when only compressive load is applied, bending stress of more than 10 times the compression stress was generated in the rod, and the stress tended to concentrate on one rod. Rod deformation becomes kyphotic, in contrast to the lordotic deformation behavior of the lumbar spine. The stress shielding rate was approximately 40%, less than half. Conclusions This study obtained basic data useful for constructing and verifying numerical simulations that are effective for predicting and elucidating the causes of dislodgement and failure of spinal implants.

METHODS: 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 (β = 2.46, P = .012), postoperative blood transfusion (β = 2.36, P = .015), any transfusion (β = 2.49, P < .001), total transfusion volume (β = 180.8, P = .020), and estimated blood loss (EBL) (β = 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.
CONCLUSIONS: 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.
METHODS: Level II.

BACKGROUND: Spinal instrumentation-related infections (SIRI) are one of the main causes of post-surgical complication and comorbidity. Our objective was to describe the clinical and microbiological characteristics, treatment and prognosis of these infections.
METHODS: We conducted a retrospective study in our institution (2011-2018) including adult patients undergoing spinal instrumentation who met the diagnostic criteria for confirmed infection. Superficial surgical wound and deep intraoperative samples were processed for microbiological culture. The medical and orthopaedic team was always the same.
RESULTS: Forty-one cases were diagnosed of which 39 patients (95.1%) presented early infection (<3 months after initial surgery) with symptoms in the first two weeks, mean CRP at diagnosis was 133mg/dl and 23% associated bacteremia. The remaining two patients (4.8%) were chronic infections (symptoms >3 months after surgery). The treatment of choice in early infections was the Debridement, Antibiotics and Implant Retention (DAIR) strategy without removal of the bone graft, which successfully resolved 84.2% of the infections. The main aetiology was gram-positive (Staphylococcus aureus: 31.7%), followed by gram-negative and polymicrobial flora. Antibiotics were optimised according to cultures with a mean duration of 12 weeks.
CONCLUSIONS: In early infections, early diagnosis and DAIR strategy (with bone graft retention) demonstrated a healing rate higher than 80%.

OBJECTIVE: Spondylodiscitis refers to infection of the intervertebral disk and neighboring structures. Outcomes based on instrumentation type are not well reported in the literature, but are important in establishing guidelines for surgical management of spondylodiscitis. This study aims to clarify the effect of instrumentation material selection on clinical and radiographic outcomes in patients with spondylodiscitis.
METHODS: Studies that evaluated the use of polyetheretherketone (PEEK), titanium, allograft, and/or autologous bone grafts for spondylodiscitis were identified in the literature. Radiographic and clinical data were analyzed using a meta-analysis of proportions, with estimated risk and confidence intervals reported for our primary study outcomes.
RESULTS: Thirty-two retrospective studies totaling 1088 patients undergoing surgical management of spondylodiscitis with PEEK, TTN, allograft, and autologous bone graft instrumentation were included. There were no differences in fusion rates (p-interaction = 0.55) with rates of fusion of 93.4% with TTN, 98.6% with allograft, 84.2% with autologous bone graft, and 93.9% with PEEK. There were no differences in screw loosening (p-interaction = 0.52) with rates of 0.33% with TTN, 0% with allograft, 1.3% with autologous bone graft, and 8.2% with PEEK. There were no differences in reoperation (p-interaction = 0.59) with rates of 2.64% with TTN, 0% with allograft, 1.69% with autologous bone graft, and 3.3% with PEEK.
CONCLUSIONS: This meta-analysis demonstrates that the choice of instrumentation type in the surgical management of spondylodiscitis resulted in no significant differences in rate of radiographic fusion, screw loosening, or reoperation. Future comparative studies to optimize guidelines for the management of spondylodiscitis are needed.

Patients with myelomeningocele associated with severe kyphoscoliosis usually presented with rigid and angulated gibbus at their back. The condition causes this group of patients to face difficulties in their daily activities, especially in sitting and lying in supine positions. They are also prone to have a pressure sore over the gibbus and encounter the risk of infection. Here the authors would present a case of a four-year-old girl with underlying myelomeningocele who was diagnosed with worsening kyphoscoliosis along her growth. Her whole spine x-ray radiograph revealed a kyphosis angle of 80° between the T11 and L4 levels. The patient underwent a deformity corrective surgery with total kyphectomy in a combination of anterior and posterior spinal instrumentation. In the present case, we were able to obtain sufficient correction of the spinal kyphotic deformity in that patient in a single-stage surgery with satisfactory surgical outcomes at a four years follow-up.