Fogelson, Jeremy L.

OBJECTIVEThe authors sought to assess whether Hounsfield units (HU) increase following teriparatide treatment and to compare HU increases with changes in bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry (DEXA).METHODSA retrospective chart review was performed from 1997 to 2018 across all campuses at our institution. The authors identified patients who had been treated with at least 6 months of teriparatide and compared HU and BMD as measured on DEXA scans before and after treatment.RESULTSFifty-two patients were identified for analysis (46 women and 6 men, average age 67 years) who underwent an average of 20.9 ± 6.5 months of teriparatide therapy. The mean ± standard deviation HU increase throughout the lumbar spine (L1–4) was from 109.8 ± 53 to 133.9 ± 61 HU (+22%, 95% CI 1.2–46, p value = 0.039). Based on DEXA results, lumbar spine BMD increased from 0.85 to 0.93 g/cm2 (+9%, p value = 0.044). Lumbar spine T-scores improved from −2.4 ± 1.5 to −1.7 ± 1.5 (p value = 0.03). Average femoral neck T-scores improved from −2.5 ± 1.1 to −2.3 ± 1.0 (p value = 0.31).CONCLUSIONSTeriparatide treatment increased both HU and BMD on DEXA in the lumbar spine, without a change in femoral BMD. The 22% improvement in HU surpassed the 9% improvement determined with DEXA. These results support some surgeons’ subjective sense that intraoperative bone quality following teriparatide treatment is better than indicated by DEXA results. To the authors’ knowledge, this is the first study demonstrating an increase in HU with teriparatide treatment.

Abstract BACKGROUND Surgical site infections (SSIs) after spine and brain surgery present a major burden to patients and hospitals by increasing morbidity, mortality, and healthcare costs. OBJECTIVE To review available literature investigating the role of intrawound powdered vancomycin against SSIs after neurosurgical operations. METHODS All randomized and observational English language studies of intrawound powdered vancomycin use in spinal and cranial surgery were included and analyzed using random-effects modeling. RESULTS In spine surgery (25 studies with 16 369 patients), patients in the vancomycin group had a significantly lower risk for any SSI (odds ratio [OR]: 0.41; 95% confidence interval [CI]: 0.30-0.57; P < .001; I 2 = 47%). However, when separate analyses were conducted for superficial and deep SSIs, a significant difference was found only for deep (OR: 0.31; 95% CI: 0.22-0.45; P < .001; I 2 = 29%). Subgroup analyses for different vancomycin powder dosages (1 g vs 2 g vs composite dose) did not point to any dose-related effect of vancomycin. In cranial surgery (6 studies with 1777 patients), use of vancomycin was associated with a significantly lower risk for SSIs (OR: 0.33; 95% CI: 0.18-0.60; P = .0003; I 2 = 45%). In meta-regression analysis, trial-level variability of diabetes had no influence on the association of vancomycin powder use with SSIs. CONCLUSION Use of vancomycin powder in spinal and cranial surgery might be protective against SSIs, especially against deep SSIs. No dose-related effect of vancomycin powder was identified. However, caution is needed in the clinical interpretation of these results, owing to the observational design of the included studies in this meta-analysis.

Study Design: Retrospective review. Objectives: This study investigates the prevalence of adverse postsurgical events, or osteoporosis-related complications (ORCs), following spinal fusion. Methods: Patients undergoing primary posterior thoracolumbar or lumbar fusion by 1 of 2 surgeons practicing at a single institution were analyzed from 2007 to 2014. ORCs were defined in one of the following categories: revision surgery, compression fracture, proximal junctional kyphosis, pseudarthrosis, or failure of instrumentation. Patients with a bone mineral density of the hips and/or spine performed within 1 year of the index procedure were included. Patients were stratified into normal bone density, osteopenia, and osteoporosis using WHO guidelines. Patients were excluded if they were younger than 18 years at the time of surgery, with infection, malignancy, skeletal dysplasia, neuromuscular disorders, concomitant or staged anterior-posterior procedure, or fusion performed because of trauma. Results: Out of 140 patients included, the prevalence of normal bone density was 31.4% (44/140), osteopenia 58.6% (82/140), and osteoporosis 10.0% (14/140). There were no differences between groups for gender, age, body mass index, and interbody device rate. The overall prevalence of ORCs was 32.1% (45/140). By group, there was a prevalence of 22.7% (10/44), 32.9% (27/82), and 50.0% (7/14) for normal bone density, osteopenia, and osteoporosis, respectively. These differences were significantly higher for both the osteopenia and osteoporosis groups. Conclusions: Patients with T scores below −1.0 undergoing posterior lumbar fusion have an increased prevalence of ORCs. Consideration of bone density plays a crucial role in patient selection, medical management, and counseling patient expectations.

Background: In pediatric patients, pedicle screws are malpositioned 5% to 15% of the time. Complications associated with malpositioned screws are infrequently reported in the literature. We present a series of adolescent idiopathic scoliosis (AIS) patients who presented in a delayed manner with positional headache and chronic dural leak adjacent to the pedicle screw tract. Methods: Scoliosis databases at 2 centers were reviewed, and cases of delayed positional headaches following posterior spinal fusion for AIS were identified. Demographic and clinical data were collected. Results: Of 322 patients, 4 patients presented with positional headaches at a mean of 12.8 weeks following posterior spinal fusion surgery for AIS, with an interval time to diagnosis of 5 months. Computed tomographic myelogram demonstrated severe pedicle screw malposition in 1 patient, and minimal malposition in 3 patients (<2 mm violation). The patients had delayed presentation with positional headaches secondary to dural leak. All patients successfully underwent revision surgery with repair of the dural leak. At the time of latest follow-up, all patients are asymptomatic. Conclusions: Pedicle screw malposition can result in dural leaks. Patients may present in a delayed manner with positional headaches and an acquired Chiari malformation. Clinical suspicion should prompt imaging of the brain or cervical spine followed by computed tomographic myelogram to determine site of leak. This is a rare complication from pedicle screw malposition. Levels of Evidence: Level IV—case series.

Study Design: A multicenter, retrospective case series. Objective: In the past several years, screw fixation of the cervical spine has become commonplace. For the most part, this is a safe, low-risk procedure. While rare, screw backout or misplaced screws can lead to morbidity and increased costs. We report our experiences with this uncommon complication. Methods: A multicenter, retrospective case series was undertaken at 23 institutions in the United States. Patients were included who underwent cervical spine surgery from January 1, 2005, to December 31, 2011, and had misplacement of screws requiring reoperation. Institutional review board approval was obtained at all participating institutions, and detailed records were sent to a central data center. Results: A total of 12 903 patients met the inclusion criteria and were analyzed. There were 11 instances of screw backout requiring reoperation, for an incidence of 0.085%. There were 7 posterior procedures. Importantly, there were no changes in the health-related quality-of-life metrics due to this complication. There were no new neurologic deficits; a patient most often presented with pain, and misplacement was diagnosed on plain X-ray or computed tomography scan. The most common location for screw backout was C6 (36%). Conclusions: This study represents the largest series to tabulate the incidence of misplacement of screws following cervical spine surgery, which led to revision procedures. The data suggest this is a rare event, despite the widespread use of cervical fixation. Patients suffering this complication can require revision, but do not usually suffer neurologic sequelae. These patients have increased cost of care. Meticulous technique and thorough knowledge of the relevant anatomy are the best means of preventing this complication.

Study Design: Multi-institutional retrospective case series of 8887 patients who underwent anterior cervical spine surgery. Objective: Anterior decompression from discectomy or corpectomy is not without risk. Surgical morbidity ranges from 9% to 20% and is likely underreported. Little is known of the incidence and effects of rare complications on functional outcomes following anterior spinal surgery. In this retrospective review, we examined implant extrusions (IEs) following anterior cervical fusion. Methods: A retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were reviewed to identify occurrence of 21 predefined treatment complications. Results: Following anterior cervical fusion, the incidence of IE ranged from 0.0% to 0.8% across 21 institutions with 11 cases reported. All surgeries involved multiple levels, and 7/11 (64%) involved either multilevel corpectomies or hybrid constructs with at least one adjacent discectomy to a corpectomy. In 7/11 (64%) patients, constructs ended with reconstruction or stabilization at C7. Nine patients required surgery for repair and stabilization following IE. Average length of hospital stay after IE was 5.2 days. Only 2 (18%) had residual deficits after reoperation. Conclusions: IE is a very rare complication after anterior cervical spine surgery often requiring revision. Constructs requiring multilevel reconstruction, especially at the cervicothoracic junction, have a higher risk for failure, and surgeons should proceed with caution in using an anterior-only approach in these demanding cases. Surgeons can expect most patients to regain function after reoperation.

Study Design Retrospective study. Objective This study reviews 1,768 consecutive cervical decompressions with or without instrumented fusion to identify patient-specific and procedural risk factors significantly correlated with the development of delayed cervical palsy (DCP). Methods Baseline demographic and procedural information was collected from the electronic medical record. Particular attention was devoted to reviewing each chart for recognized risk factors of postsurgical inflammatory neuropathy: autoimmune disease, blood transfusions, diabetes, and smoking. Results Of 1,669 patients, 56 (3.4%) developed a DCP. Although 71% of the palsies involved C5, 55% of palsies were multimyotomal and 18% were bilateral. Significant risk factors on univariate analysis included age ( p = 0.0061, odds ratio [OR] = 1.07, 95% confidence interval [CI] 1.008 to 1.050), posterior instrumented fusion ( p < 0.0001, OR = 3.30, 95% CI 1.920 to 5.653), prone versus semisitting/sitting position ( p = 0.0036, OR = 3.58, 95% CI 1.451 to 11.881), number of operative levels ( p < 0.0001, OR = 1.42, 95% CI 1.247 to 1.605), intraoperative transfusions ( p = 0.0231, OR = 2.57, 95% CI 1.152 to 5.132), and nonspecific autoimmune disease ( p = 0.0107, OR = 3.83, 95% CI 1.418 to 8.730). On multivariate analysis, number of operative levels ( p = 0.0053, OR = 1.27, 95% CI 1.075 to 1.496) and nonspecific autoimmune disease ( p = 0.0416, OR 2.95, 95% CI 1.047 to 7.092) remained significant. Conclusions Although this study partially supports a mechanical etiology in the pathogenesis of a DCP, we also describe a notable correlation with autoimmune risk factors. Bilateral and multimyotomal involvement provides additional support that some DCPs may result from an inflammatory response and thus an underlying multifactorial etiology for this complication.

OBJECT Endoscopic approaches to the anterior craniocervical junction are increasing in frequency. Choice of oral versus endoscopic endonasal approach to the odontoid often depends on the relationship of the C1–2 complex to the hard palate. However, it is not known how this relevant anatomy changes with age. We hypothesize that there is a dynamic relationship of C-2 and the hard palate, which changes with age, and potentially affects the choice of surgical approach. The aim of this study was to characterize the relationship of C-2 relative to the hard palate with respect to age and sex. METHODS Emergency department billing and trauma records from 2008 to 2014 were reviewed for patients of all ages who underwent cervical or maxillofacial CT as part of a trauma evaluation for closed head injury. Patients who had a CT scan that allowed adequate visualization of the hard palate, opisthion, and upper cervical spine (C-1 and C-2) were included. Patients who had cervical or displaced facial/skull base fractures, a history of rheumatoid arthritis, or craniofacial anomalies were excluded. The distance from McGregor's palatooccipital line to the midpoint of the inferior endplate of C-2 (McL–C2) was measured on midsagittal CT scans. Patients were grouped by decile of age and by sex. A 1-way ANOVA was performed with each respective grouping. RESULTS Ultimately, 483 patients (29% female) were included. The mean age was 46 ± 24 years. The majority of patients studied were in the 2nd through 8th decades of life (85%). Significant variation was found between McL–C2 and decile of age (p < 0.001) and sex (p < 0.001). The mean McL–C2 was 27 mm in the 1st decade of life compared with the population mean of 37 mm. The mean McL–C2 was also noted to be smaller in females (mean difference 4.8 mm, p < 0.0001). Both decile of age (p = 0.0009) and sex (p < 0.0001) were independently correlated with McL–C2 on multivariate analysis. CONCLUSIONS The relationship of C-2 and the hard palate significantly varies with respect to age and sex, descending relative to the hard palate a full centimeter on average in adulthood. These findings may have relevance in determining optimal surgical approaches for addressing pathology involving the anterior craniocervical junction.