Pennington, Zach

OBJECTIVE The purpose of this study was to determine the effect of osteoporosis medications on opportunistic CT-based Hounsfield units (HU). METHODS Spine and nonspine surgery patients were retrospectively identified who had been treated with romosozumab for 3 to 12 months, teriparatide for 3 to 12 months, teriparatide for > 12 months, denosumab for > 12 months, or alendronate for > 12 months. HU were measured in the L1–4 vertebral bodies. One-way ANOVA was used to compare the mean change in HU among the five treatment regimens. RESULTS In total, 318 patients (70% women) were included, with a mean age of 69 years and mean BMI of 27 kg/m 2 . There was a significant difference in mean HU improvement (p < 0.001) following treatment with romosozumab for 3 to 12 months (n = 32), teriparatide for 3 to 12 months (n = 30), teriparatide for > 12 months (n = 44), denosumab for > 12 months (n = 123), and alendronate for > 12 months (n = 100). Treatment with romosozumab for a mean of 10.5 months significantly increased the mean HU by 26%, from a baseline of 85 to 107 (p = 0.012). Patients treated with teriparatide for > 12 months (mean 23 months) experienced a mean HU improvement of 25%, from 106 to 132 (p = 0.039). Compared with the mean baseline HU, there was no significant difference after treatment with teriparatide for 3 to 12 months (110 to 119, p = 0.48), denosumab for > 12 months (105 to 107, p = 0.68), or alendronate for > 12 months (111 to 113, p = 0.80). CONCLUSIONS Patients treated with romosozumab for a mean of 10.5 months and teriparatide for a mean of 23 months experienced improved spinal bone mineral density as estimated by CT-based opportunistic HU. Given the shorter duration of effective treatment, romosozumab may be the preferred medication for optimization of osteoporotic patients in preparation for elective spine fusion surgery.

OBJECTIVE Tranexamic acid (TXA) is an FDA-approved antifibrinolytic that is seeing increased popularity in spine surgery owing to its ability to reduce intraoperative blood loss (IOBL) and allogeneic transfusion requirements. The present study aimed to summarize the current literature on these formulations in the context of short-segment instrumented lumbar fusion including ≥ 1-level posterior lumbar interbody fusion (PLIF). METHODS The PubMed, Cochrane, and Web of Science databases were queried for all full-text English studies evaluating the use of topical TXA (tTXA), systemic TXA (sTXA), or combined tTXA+sTXA in patients undergoing PLIF. The primary endpoints of interest were operative time, IOBL, and total blood loss (TBL); secondary endpoints included venous thromboembolic complication occurrence, and allogeneic and autologous transfusion requirements. Outcomes were compared using random effects. Comparisons were made between the following treatment groups: sTXA, tTXA, and sTXA+tTXA. Given that sTXA is arguably the standard of care in the literature (i.e., the most common route of administration that to this point has been studied the most), the authors compared sTXA versus tTXA and sTXA versus sTXA+tTXA. Study heterogeneity was assessed with the I2 test, and grouped analysis using the Hedge’s g test was performed for measurement of effect size. RESULTS Forty-five articles were identified, of which 17 met the criteria for inclusion with an aggregate of 1008 patients. TXA regimens included sTXA only, tTXA only, and various combinations of sTXA and tTXA. There were no significant differences in operative time, TBL, or postoperative drainage between the sTXA and tTXA groups or between the sTXA and sTXA+tTXA groups. CONCLUSIONS The present meta-analysis suggested clinical equipoise between isolated sTXA, isolated tTXA, and combinatorial tTXA+sTXA formulations as hemostatic adjuvants/neoadjuvants in short-segment fusion including ≥ 1-level PLIF. Given the theoretically lower venous thromboembolism risk associated with tTXA, additional investigations using large cohorts comparing these two formulations within the posterior fusion population are merited. Although TXA has been shown to be effective, there are insufficient data to support topical or systemic administration as superior within the open PLIF population.

Abstract Introduction Here we systematically review the extant literature to highlight the advantages of bilateral versus unilateral approaches and endoscopic endonasal (midline) approaches versus transcranial approaches for olfactory groove meningiomas, focusing on complications, extent of resection, and local recurrence rates. Methods Three databases were queried to identify all primary prospective trials and retrospective series comparing outcomes following endoscopic endonasal versus transcranial approaches and unilateral versus bilateral craniotomy for surgical resection of olfactory groove meningiomas. All articles were screened by two independent authors and selected for formal analysis according to predefined inclusion/exclusion criteria. Results Seven studies comprising 288 total patients (mean age 55.0 ± 24.6 years) met criteria for inclusion. In the three comparing the endoscopic endonasal (n = 21) versus transcranial (n = 32) approaches, there was no significant difference between the two with respect to gross total resection (p = 0.34) or rates of Simpson Grade 1 resection (p = 0.69). EEA demonstrated higher rates of overall complications (p < 0.01) including postoperative infection (p = 0.03). In the four studies comparing bilateral (n = 117) versus unilateral approaches (n = 118), overall complication rates (p < 0.01) and disease recurrence (p = 0.01) were higher with bilateral approaches. All surgery-related mortalities also occurred in the bilateral cohort (n = 7, 7.14%). Gross total resection (p = 0.63) and Simpson grade (p = 0.48) were comparable between approaches. Olfaction preservation was superior for unilateral approaches (p < 0.01). Conclusion Though the literature is limited, current evidence suggests that the endoscopic endonasal approach may be favorable over conventional craniotomy for select olfactory groove meningioma patients. Where craniotomy is used, unilateral approaches appear to reduce complications and the risk of olfaction loss.

BACKGROUND AND OBJECTIVES: Cervical disk arthroplasty (CDA) offers the advantage of motion preservation in the treatment of focal cervical pathology. At present, implant sizing is performed using subjective tactile feedback and imaging of trial cages. This study aims to construct interpretable machine learning (IML) models to accurately predict postoperative range of motion (ROM) and identify the optimal implant sizes that maximize ROM in patients undergoing CDA. METHODS: Adult patients who underwent CDA for single-level disease from 2012 to 2020 were identified. Patient demographics, comorbidities, and outcomes were collected, including symptoms, examination findings, subsidence, and reoperation. Affected disk height, healthy rostral disk height, and implant height were collected at sequential time points. Linear regression and IML models, including bagged regression tree, bagged multivariate adaptive regression spline, and k-nearest neighbors, were used to predict ROM change. Model performance was assessed by calculating the root mean square error (RMSE) between predicted and actual changes in ROM in the validation cohort. Variable importance was assessed using RMSE loss. Area under the curve analyses were performed to identify the ideal implant size cutoffs in predicting improved ROM. RESULTS: Forty-seven patients were included. The average RMSE between predicted and actual ROM was 7.6° (range: 5.8-10.1) in the k-nearest neighbors model, 7.8° (range: 6.5-10.0) in the bagged regression tree model, 7.8° (range: 6.2-10.0) in the bagged multivariate adaptive regression spline model, and 15.8° (range: 14.3-17.5°) in a linear regression model. In the highest-performing IML model, graft size was the most important predictor with RMSE loss of 6.2, followed by age (RMSE loss = 5.9) and preoperative caudal disk height (RMSE loss = 5.8). Implant size at 110% of the normal adjacent disk height was the optimal cutoff associated with improved ROM. CONCLUSION: IML models can reliably predict change in ROM after CDA within an average of 7.6 degrees of error. Implants sized comparably with the healthy adjacent disk may maximize ROM.

BACKGROUND Adult spinal deformity (ASD) occurs from progressive anterior column collapse due to disc space desiccation, compression fractures, and autofusion across disc spaces. Anterior column realignment (ACR) is increasingly recognized as a powerful tool to address ASD by progressively lengthening the anterior column through the release of the anterior longitudinal ligament during lateral interbody approaches. Here, we describe the application of minimally invasive ACR through an oblique antepsoas corridor for deformity correction in a patient with adult degenerative scoliosis and significant sagittal imbalance. OBSERVATIONS A 65-year-old female with a prior history of L4–5 transforaminal lumbar interbody fusion and morbid obesity presented with refractory, severe low-back and lower-extremity pain. Preoperative radiographs showed significant sagittal imbalance. Computed tomography showed a healed L4–5 fusion and a vacuum disc at L3–4 and L5–S1, whereas magnetic resonance imaging was notable for central canal stenosis at L3–4. The patient was treated with a first-stage L5–S1 lateral anterior lumbar interbody fusion with oblique L2–4 ACR. The second-stage posterior approach consisted of a robot-guided minimally invasive T10–ilium posterior instrumented fusion with a mini-open L2–4 posterior column osteotomy (PCO). Postoperative radiographs showed the restoration of her sagittal balance. There were no complications. LESSONS Oblique ACR is a powerful minimally invasive tool for sagittal plane correction. When combined with a mini-open PCO, substantial segmental lordosis can be achieved while eliminating the need for multilevel PCO or invasive three-column osteotomies.

Background: Multisegmental pathologic autofusion occurs in patients with ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH). It may lead to reduced vertebral bone density due to stress shielding. Methods: This study aimed to determine the effects of autofusion on bone density by measuring Hounsfield units (HU) in the mobile and immobile spinal segments of patients with AS and DISH treated at a tertiary care center. The mean HU was calculated for five distinct regions—cranial adjacent mobile segment, cranial fused segment, mid-construct fused segment, caudal fused segment, and caudal adjacent mobile segment. Means for each region were compared using paired-sample t-tests. Multivariable regression was used to determine independent predictors of mid-fused segment HUs. Results: One hundred patients were included (mean age 76 ± 11 years, 74% male). The mean HU for the mid-construct fused segment (100, 95% CI [86, 113]) was significantly lower than both cranial and caudal fused segments (174 and 108, respectively; both p < 0.001), and cranial and caudal adjacent mobile segments (195 and 115, respectively; both p < 0.001). Multivariable regression showed the mid-construct HUs were predicted by history of smoking (−30 HU, p = 0.009). Conclusions: HUs were significantly reduced in the middle of long-segment autofusion, which was consistent with stress shielding. Such shielding may contribute to the diminution of vertebral bone integrity in AS/DISH patients and potentially increased fracture risk.