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BackgroundAs of May 4, 2020, the coronavirus disease 2019 (COVID-19) pandemic has affected >3.5 million people and touched every inhabited continent. Accordingly, it has stressed health systems worldwide, leading to the cancellation of elective surgical cases and discussions regarding health care resource rationing. It is expected that rationing of surgical resources will continue even after the pandemic peak and may recur with future pandemics, creating a need for a means of triaging patients for emergent and elective spine surgery.MethodsUsing a modified Delphi technique, a cohort of 16 fellowship-trained spine surgeons from 10 academic medical centers constructed a scoring system for the triage and prioritization of emergent and elective spine surgeries. Three separate rounds of videoconferencing and written correspondence were used to reach a final scoring system. Sixteen test cases were used to optimize the scoring system so that it could categorize cases as requiring emergent, urgent, high-priority elective, or low-priority elective scheduling.ResultsThe devised scoring system included 8 independent components: neurologic status, underlying spine stability, presentation of a high-risk postoperative complication, patient medical comorbidities, expected hospital course, expected discharge disposition, facility resource limitations, and local disease burden. The resultant calculator was deployed as a freely available Web-based calculator (https://jhuspine3.shinyapps.io/SpineUrgencyCalculator/).ConclusionsWe present the first quantitative urgency scoring system for the triage and prioritizing of spine surgery cases in resource-limited settings. We believe that our scoring system, although not all encompassing, has potential value as a guide for triaging spine surgical cases during the COVID pandemic and post-COVID period.

Purpose: To characterize the 3D imaging performance and radiation dose for a prototype slot‐beam configuration on an intraoperative O‐arm™ Surgical Imaging System (Medtronic Inc., Littleton, MA) and identify potential improvements in soft‐tissue image quality for surgical interventions. Methods: A slot collimator was integrated with the O‐arm™ system for slot‐beam axial CT. The collimator can be automatically actuated to provide 1.2° slot‐beam longitudinal collimation. Cone‐beam and slot‐beam configurations were investigated with and without an antiscatter grid (12:1 grid ratio, 60 lines/cm). Dose, scatter, image noise, and soft‐tissue contrast resolution were evaluated in quantitative phantoms for head and body configurations over a range of exposure levels (beam energy and mAs), with reconstruction performed via filtered‐backprojection. Qualitative imaging performance across various anatomical sites and imaging tasks was assessed with anthropomorphic head, abdomen, and pelvis phantoms. Results: The dose for a slot‐beam scan varied from 0.02–0.06 mGy/mAs for head protocols to 0.01–0.03 mGy/mAs for body protocols, yielding dose reduction by ∼1/5 to 1/3 compared to cone‐beam, owing to beam collimation and reduced x‐ray scatter. The slot‐beam provided an ∼6–7× reduction in scatter‐to‐primary ratio (SPR) compared to the cone‐beam, yielding SPR ∼20–80% for head and body without the grid and ∼7–30% with the grid. Compared to cone‐beam scans at equivalent dose, slot‐beam images exhibited an ∼2.5× increase in soft‐tissue contrast‐to‐noise ratio (CNR) for both grid and gridless configurations. For slot‐beam scans, a further ∼10–30% improvement in CNR was achieved when the grid was removed. Slot‐beam imaging could benefit certain interventional scenarios in which improved visualization of soft tissues is required within a fairly narrow longitudinal region of interest (±7 mm in z)––for example, checking the completeness of tumor resection, preservation of adjacent anatomy, or detection of complications (e.g., hemorrhage). While preserving existing capabilities for fluoroscopy and cone‐beam CT, slot‐beam scanning could enhance the utility of intraoperative imaging and provide a useful mode for safety and validation checks in image‐guided surgery. Conclusions: The 3D imaging performance and dose of a prototype slot‐beam CT configuration on the O‐arm™ system was investigated. Substantial improvements in soft‐tissue image quality and reduction in radiation dose are evident with the slot‐beam configuration due to reduced x‐ray scatter. [ABSTRACT FROM AUTHOR]

Purpose: Intraoperative imaging plays an increased role in support of surgical guidance and quality assurance for interventional approaches. However, image quality sufficient to detect complications and provide quantitative assessment of the surgical product is often confounded by image noise and artifacts. In this work, we translated a three‐dimensional model‐based image reconstruction (referred to as "Known‐Component Reconstruction," KC‐Recon) for the first time to clinical studies with the aim of resolving both limitations. Methods: KC‐Recon builds upon a penalized weighted least‐squares (PWLS) method by incorporating models of surgical instrumentation ("known components") within a joint image registration–reconstruction process to improve image quality. Under IRB approval, a clinical pilot study was conducted with 17 spine surgery patients imaged under informed consent using the O‐arm cone‐beam CT system (Medtronic, Littleton MA) before and after spinal instrumentation. Volumetric images were generated for each patient using KC‐Recon in comparison to conventional filtered backprojection (FBP). Imaging performance prior to instrumentation ("preinstrumentation") was evaluated in terms of soft‐tissue contrast‐to‐noise ratio (CNR) and spatial resolution. The quality of images obtained after the instrumentation ("postinstrumentation") was assessed by quantifying the magnitude of metal artifacts (blooming and streaks) arising from pedicle screws. The potential low‐dose advantages of the algorithm were tested by simulating low‐dose data (down to one‐tenth of the dose of standard protocols) from images acquired at normal dose. Results: Preinstrumentation images (at normal clinical dose and matched resolution) exhibited an average 24.0% increase in soft‐tissue CNR with KC‐Recon compared to FBP (N = 16, P = 0.02), improving visualization of paraspinal muscles, major vessels, and other soft‐tissues about the spine and abdomen. For a total of 72 screws in postinstrumentation images, KC‐Recon yielded a significant reduction in metal artifacts: 66.3% reduction in overestimation of screw shaft width due to blooming (P < 0.0001) and reduction in streaks at the screw tip (65.8% increase in attenuation accuracy, P < 0.0001), enabling clearer depiction of the screw within the pedicle and vertebral body for an assessment of breach. Depending on the imaging task, dose reduction up to an order of magnitude appeared feasible while maintaining soft‐tissue visibility and metal artifact reduction. Conclusions: KC‐Recon offers a promising means to improve visualization in the presence of surgical instrumentation and reduce patient dose in image‐guided procedures. The improved soft‐tissue visibility could facilitate the use of cone‐beam CT to soft‐tissue surgeries, and the ability to precisely quantify and visualize instrument placement could provide a valuable check against complications in the operating room (cf., postoperative CT). [ABSTRACT FROM AUTHOR]

Objectives: Multiple methods of selective brain cooling have been used to prevent cerebral ischemia secondary to trauma and pathological or iatrogenic cerebral blood flow restriction. In this study, we tested the efficacy of hypothermic retrograde jugular vein flush (HRJVF) in eliciting selective brain hypothermia in a porcine model. Methods: Twelve swine were divided into two groups: retrograde jugular vein infusion (RJVI) with cold saline (4°C RJVI, n = 6) and with room temperature saline (24°C RJVI, n = 6). For 90 minutes, the following parameters were measured: brain parenchymal temperature, rectal temperature, intracranial pressure (ICP), mean arterial pressure, and heart rate (HR). Results: Swine receiving 4°C RJVI experienced a drop in mean brain parenchymal temperature of 1.1 ± 0.1°C, compared to 0.1 ± 0.1°C in swine receiving 24°C RJVI. At 90 minutes, mean brain parenchymal temperature in the 4°C RJVI treatment group was 35.5 ± 0.2°C, as compared to 37.1± 0.2°C in the 24°C RJVI treatment group (P< 0.001). In the 4°C RJVI group, the brain-systemic temperature gradient peaked 10 minutes after initiation of cooling and remained significantly different when comparing the two experimental groups (P < 0.001) throughout the duration of the 90 minutes experiment. Of note, ICP, mean arterial pressure, and HR remained constant without any significant changes or differences between treatment groups. Discussion: These results suggest that HRJVF is an effective method for selective brain hypothermia in a large animal model. Clinical application may prove effective in delaying neural ischemia. [ABSTRACT FROM AUTHOR]

Abstract: Pseudomeningoceles are extradural cerebrospinal fluid collections categorized into three groups: traumatic, congenital, and iatrogenic. Iatrogenic pseudomeningoceles occur after durotomy, usually after cervical or lumbar spine surgery. Although many remain asymptomatic, pseudomeningoceles can compress or herniate the spinal cord and nerve roots. We present a 57-year-old woman who had a thoracic laminectomy and discectomy. Two weeks after surgery, she presented with lower extremity weakness and gait difficulty. Physical examination revealed hyperreflexia and a T11 sensory level. MRI revealed a pseudomeningocele compressing the thoracic spinal cord. The patient underwent surgical drainage of the cyst. On follow-up, she had complete resolution of her symptoms, and MRI did not show a residual lesion. To our knowledge, this is the second documented post-operative pseudomeningocele causing symptomatic spinal cord compression of the thoracic spine. In this article, a review of the literature is presented, including four reported patients with post-traumatic pseudomeningocele causing myelopathic symptoms and 20 patients with iatrogenic pseudomeningocele that resulted in neurological decline due to herniation or compression of neural tissue. Treatment options for these lesions include conservative management, epidural blood patch, lumbar subarachnoid drainage, and lumbo-peritoneal shunt placement. Surgical repair, usually by primary dural closure, remains the definitive treatment modality for iatrogenic symptomatic pseudomeningoceles. [Copyright &y& Elsevier]

Comparative effectiveness research has a vital role in health reform and policies. Specialty training is one of these provider-side variables, and surgeons performing the same procedure who were trained in different specialties may have different outcomes. The objective of this study was to investigate the impact of spine surgeon specialty (neurosurgery vs. orthopedic surgery) on early perioperative outcome measures of elective anterior/lateral lumbar interbody fusion (ALIF/LLIF) for degenerative disc diseases. In a retrospective, 1:1 propensity score–matched cohort study, 9070 patients were reviewed from the American College of Surgeons National Surgical Quality Improvement Program database. Propensity score matching and subgroup analysis were used. In both groups (single-level and multilevel ALIF/LLIF), patients operated on by neurosurgeons had longer operative time (188 minutes vs. 172 minutes/239 minutes vs. 221 minutes); shorter total hospital stay (71 hours vs. 90 hours/89 hours vs. 96 hours); and lower rates of return to the operating room (2.1% vs. 4.1%/2.4% vs. 4.2%), nonhome discharge (8.7% vs. 11.1%/10.1% vs. 14.9%), discharge after postoperative day 3 (22.0% vs. 30.0%/38.0% vs. 43.9%), and perioperative blood transfusion (2.1% vs. 5.1%/5.0% vs. 9.9%) (P < 0.05). In multilevel ALIF/LLIF, patients operated on by neurosurgeons had lower readmission rates (3.9% vs. 6.9%) (P < 0.05). Other outcome measures and mortality rates were similar between the single-level and multilevel ALIF/LLIF cohorts regardless of surgeon specialty. Our analysis found significant differences in early perioperative outcomes of patients undergoing ALIF/LLIF by neurosurgeons and orthopedic surgeons. These differences have significant clinical and cost implications for patients, physicians, program directors, payers, and health systems. [ABSTRACT FROM AUTHOR]

Background Context: Recently, preclinical and clinical studies suggest an association between renin-angiotensin system (RAS) blockers and bone healing, particularly in the context of osteoporotic bone fractures.Purpose: To determine the correlation between the use of RAS inhibitors and fusion outcomes and neurologic status in anterior cervical discectomy and fusion (ACDF) surgery.Study Design: Retrospective observational study.Patient Sample: Patients who underwent ACDF for degenerative disorders.Outcome Measures: Spinal fusion status and neurologic function (modified Japanese Orthopedic Association [mJOA] and Nurick grading scales).Methods: A retrospective chart review was performed, including 200 patients who underwent ACDF for degenerative disorders with 1-year minimum follow-up. Demographic data, comorbidities, antihypertensive medication, neurologic examination, and fusion status were collected. Spinal fusion was assessed via plain cervical x-ray, resorting to dynamic radiographs and/or computer tomography (CT) in cases of uncertainty. Preoperative mJOA and Nurick scores and recovery rates were calculated to determine neurologic status.Results: Of the 200 patients (42.5% females, 57.5% males, median age of 53.7 years), 82 hypertensive patients were identified. Seventy-seven (93.9%) were taking antihypertensive medication as follows: 36.4% angiotensin-II receptor blockers (ARBs), 35.1% angiotensin-converting enzyme inhibitors (ACEIs), and the remaining patients were taking other medication. In the analysis of fusion rates, patients treated with ARBs exhibited a higher fusion rate, while those treated with ACEIs displayed a lower fusion rate compared to untreated nonhypertensive patients (p = .04 and .02, respectively). The difference in fusion rates between ARBs and ACEIs was also significant, with the former displaying higher rates (p < .001). Smoking exhibited a negative correlation with spinal fusion (p < .001). In the multivariate analysis, ARBs remained an independent factor for successful fusion (p = .02), while smoking remained a risk factor for failed fusion (p = .002). In the neurologic examination, ACEIs, hypertension status, and older age correlated with lower modified Japanese Orthopedic Association (mJOA) recovery rates (p = .001, <.001, and <.001, respectively) in the univariate analysis.Conclusions: In ACDF patients, we observed that ARBs were associated with higher fusion rates. Conversely, ACEIs and smoking were related to failed fusion. Prospective case-control studies are needed to confirm these RAS inhibitors effects on spinal fusion. [ABSTRACT FROM AUTHOR]

Background Posterior atlantoaxial fusion is an important armamentarium for neurosurgeons to treat several pathologies involving the craniovertebral junction. Although the potential advantages of recombinant human bone morphogenetic protein-2 (rhBMP-2) are well documented in the lumbar spine, its indication for C1-C2 fusion has not been well characterized. In our institution, we apply rhBMP-2 to the C1-C2 joint either alone or with hydroxyapatite, locally harvested autograft chips, and/or morselized allogenic bone graft for selected cases—without conventional posterior structural bone graft. We report the clinical outcomes of the surgical technique to elucidate its feasibility. Methods We performed a single-center, retrospective review of data from 2008 to 2016 and identified 69 patients who had undergone posterior atlantoaxial fusion with rhBMP-2. The clinical records of these patients were reviewed, and the baseline characteristics, operative data, and postoperative complications were collected and statistically analyzed. Results The average age of the 69 patients was 60.8 ± 4.5 years, and 55.1% were women. With an average follow-up period of 21.1 ± 4.2 months, the C1-C2 fusion rate was 94.3% (65 of 69), and the average time to fusion was 11.4 ± 2.6 months (range, 5–23). The overall reoperation rate was 10.1% (7 of 69), with instrumentation failure in 7 patients (10.1%), adjacent segment disease in 2 (2.9%), and postoperative dysphagia and dyspnea in 2 patients (2.9%). No ectopic bone formation or soft tissue edema developed. Conclusions Although retrospective and from a single center, our study has shown that rhBMP-2 usage at the C1-C2 joint without posterior structural bone grafting is a safe and reasonable surgical option. [ABSTRACT FROM AUTHOR]

Background The pathogenesis of synovial cysts is largely unknown; however, they have been increasingly thought of as markers of spinal facet instability and typically associated with degenerative spondylosis. We specifically investigated the incidence of concomitant synovial cysts with underlying degenerative spondylolisthesis. Methods A literature search was performed using 4 online databases to assess the association between lumbar synovial cysts and degenerative spinal pathological features. Meta-analyses were performed on the prevalence rates of coexisting degenerative spinal pathological entities and treatment modalities. A random effects model was used to calculate the mean and 95% confidence intervals. Results A total of 17 studies encompassing 824 cases met the inclusion criteria. The pooled prevalence rates of concurrent spondylolisthesis, facet arthropathy, and degenerative disc disease at the same level of the synovial cysts were 42.5% (range, 39.0%–46.1%), 89.3% (range, 79.0%–94.8%), and 48.8% (range, 43.8%–53.9%), respectively. Among these, patients with coexisting spondylolisthesis were more likely to undergo spinal fusion surgery (vs. laminectomy alone) and reoperation than were patients without spondylolisthesis with a pooled odds ratio of 11.5 (95% confidence interval, 4.5–29.1; P < 0.0001) and 2.0 (95% confidence interval, 0.9–4.2; P = 0.088), respectively. Conclusions Patients with a combination of synovial cysts and degenerative spondylolisthesis are more likely to undergo spinal fusion surgery than laminectomy alone compared with patients with synovial cysts and no preoperative spondylolisthesis. Furthermore, patients with synovial cysts and spondylolisthesis are more likely to require additional fusion surgery. The results from the present review lend credence to the argument that synovial cyst herniation might be a manifestation of an unstable spinal level. [ABSTRACT FROM AUTHOR]

Transplantation of adipose-derived mesenchymal stem cells (ADSCs) has become a promising approach for bone regeneration therapies, particularly in elderly patients. However, poor cell survival in vivo after implantation due to the ischemic tissue environment has been one of the major limitations of the effectiveness of this strategy. Hypoxia Inducible Factor-1α (HIF-1α) plays an important role in angiogenic-osteogenic coupling during bone regeneration, as it is a critical mediator of the adaptive cell response to hypoxia. DMOG treatment has been demonstrated to stabilize cellular expression of HIF-1α in cells, as well as enhance osteogenic and angiogenic capacity of MSCs. By therapeutically targeting both osteogenesis and vascularization via DMOG preconditioned MSCs, this tissue-engineering approach sought to yield superior bone quality and integration, thereby increasing rates of spinal fusion. We aimed to demonstrate that preconditioning adipose (ADSC)-derived (AD) MSCs with DMOG prior to implantation will prolong survival in vivo and improve spinal fusion outcomes in a rat model. In vivo study via a rat posterolateral spinal fusion model. Syngeneic 6-8 week old Lewis rats. Manual palpation scoring was performed by blinded researchers as follows: 0 = non-fused; 1 = partial fusion, some motion across operative joint; and, 2 = fused, no motion across the operated joint. MicroCT images were used to assess fusion mass volume (mm^3) via ImageJ software and determine CT fusion score (0 = non-fused; 1 = unilateral fusion; 2 = bilateral fusion). ADSCs were isolated from the inguinal fat pads of syngeneic 6-8 week old Lewis rats and cultured in vitro. When passage 1 (P1) ADSCs reached approximately 80% confluency they were pre-conditioned for 24 hours with 1 ng of DMOG (Fisher Scientific). After pre-conditioning, 2 × 10^6 ADSCs were seeded onto Vitoss (Stryker) bone graft substitute scaffolds for subsequent transplantation. Posterolateral spinal fusion surgery at L4-L5 was performed on 18 female Lewis rats divided into 2 experimental groups: [1] Vitoss+ADSCs pre-conditioned with DMOG; and, [2] Vitoss+non pre-conditioned ADSCs. Fusion was evaluated eight weeks post-surgery. Manual palpation scoring evaluated the motion across the operated joint, and MicroCT images were assessed for fusion mass volume and CT fusion. Preliminary microCT imaging data suggest that DMOG pre-conditioned ADSCs (n=12) yielded significantly higher fusion mass volumes than non-preconditioned ADSCs (n=6) (23.49 mm^3 vs. 15.39 mm^3, respectively, p=.001). DMOG pre-conditioned ADSCs showed a trend towards higher rates of fusion and manual palpation scores compared to non-conditioned ADSCs (1.16 vs. 0.50, respectively, p=.06; and 1.25 vs. 0.66, respectively, p>.05). In our rat posterolateral fusion model, DMOG pre-conditioned ADSCs displayed an increased fusion mass volume, CT fusion rates, and manual palpation score compared to non-conditioned ADSCs. Ongoing histological studies will evaluate whether there are any differences in the quality of bone formed within the fusion masses. Future studies will also compare whether these results are also similar in bone marrow-derived MSCs. Dimethyloxaloylglycine (Investigational/Not approved) [ABSTRACT FROM AUTHOR]

Approximately 132,000 patients per year undergo anterior cervical discectomy and fusion (ACDF) in the United States. Although the utilization of instrumentation and bone graft alternatives has enhanced fusion rates, pseudarthrosis remains a problem, with incidence rates up to 56%. Renin-angiotensin system (RAS) modulators are typically used to treat arterial hypertension, which affects 50-80% of spinal fusion patients. Recent evidence suggests an association between RAS blockers and bone metabolism, particularly in the context of bone healing. In addition, preclinical and clinical studies have suggested a potential correlation between the use of RAS blockers and reduced osteoporotic fracture risk. We aimed to determine whether there was a correlation between the use of antihypertensive medication, particularly angiotensin-II type-1 receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs), and outcomes in anterior cervical discectomy and fusion (ACDF) surgery. Retrospective observational study. Degenerative disc disease patients who underwent ACDF. Spinal fusion status and neurological function (modified Japanese Orthopaedic Association [mJOA] and Nurick grading scales. A cohort of adult patients with symptomatic cervical degenerative disc disease who were operated upon using an allograft implant, and with a 1-year minimum follow-up was considered eligible. Information on demographic data, comorbidities (especially hypertension status), antihypertensive medication, neurological examination and fusion status were collected. Fusion criteria in static radiographs were increased opacification and bridging trabecular bone at the margins of the graft. In dynamic radiographs, fusion criteria were interspinous motion of < 1 mm and superjacent interspinous motion of < 4 mm. For CT scans, fusion was defined as solid bridging of bone across the disc space of the intended fusion. A total of 178 patients with cervical degenerative disc disease who underwent ACDF, with a median age of 53.7 (range 24-90) years, were included in the analysis. Median follow-up was 21.7 months. Out of the 82 hypertensive patients who were identified, 77 (93.9%) were taking antihypertensive drugs (28 [36.4%] received ARBs and 27 [35.1%] received ACEIs). The overall pooled fusion rate was 69.5%. Patients treated with ARBs exhibited a higher fusion rate compared to those who were untreated (88.9% vs 69.7%, respectively, p=.04). By contrast, patients treated with ACEIs displayed a lower fusion rate than untreated patients (45.8% vs 69.7%, respectively, p=.02). Comparisons between successful fusion and failed fusion groups identified treatment with ACEIs as risk factors for the development of pseudarthrosis. Treatment with ARBs displayed a trend towards being a favorable factor for fusion (RR=1.2, 95% CI 1.0, 1.5). In the multivariate nominal logistic analysis, ARB (p=.02) treatment remained an independent risk and beneficial factor, respectively, for fusion. In our retrospective study of a cohort of ACDF patients, treatment with ARBs was associated with an increased fusion rate, while treatment with ACEIs identified as risk factor for failed fusion. Further preclinical and clinical studies are needed to verify the beneficial effects of ARBs and deleterious influence of ACEIs on spinal fusion. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT With the overall advancement in management of patients with human immunodeficiency virus (HIV) infection/AIDS, especially antiretroviral therapy regimens, HIV infection is now considered as a chronic disease and the longevity of these patients has significantly improved for the last two decades. As such, an increasing number of patients with HIV-infection are now potential candidates for elective surgical procedures such as spine surgery. In 2015, an estimated 1.1million adults and adolescents were living with HIV and 39,782 patients were newly diagnosed with HIV infection annually in 2016 (CDC data). Despite this increasing prevalence and incidence of the disease, the literature regarding clinical outcomes of spine surgery in patients with HIV is surprisingly scarce. As is the same as patients with other concurrent immunocompromising co-morbidities such as steroid use, diabetes mellitus, organ recipients, and/or chemo or radiation therapy, postoperative infection is one of the most concerning complications. Furthermore, bone mineral densities of HIV-infected patients are reported to be lower than noninfected controls, which could have some potential indications for worse long-term outcomes such as pseudoarthrosis. Thus, we aimed to characterize clinical outcomes of spine surgery in patients with HIV infection in order to facilitate judicious patient selection and comprehensive informed consent, which are of paramount importance in surgical decision-making processes for this high-risk cohort. PURPOSE Summarize clinical outcomes of spine surgery in patients with HIV, such as readmission rate, infectious complications, fusion rate, and mortality to address surgical indications for this specific cohort. STUDY DESIGN/SETTING Retrospective, single-center, propensity-matched cohort. PATIENT SAMPLE Patients who underwent spine surgery with HIV infection were included and compared with a matched-cohort without HIV infection OUTCOME MEASURES CD4 absolute count/uL, HIV-1 RNA copy numbers/mL, 30-day readmission rate, 90-day medical complication rate, one-year surgical site infectious complication rate, one-year fusion rate, and one-year mortality METHODS Single-center, retrospective data review from 2010 to 2016 yielded a total of 4,968 patients of spine surgery. Amongst those, 45 patients had HIV infection. Patients from the database were propensity-matched for age, sex, diagnoses, procedures, co-morbidities other than HIV at a 1:2 ratio, which yielded 90 matched-patients. Clinical outcomes of (A) 45 patients with HIV infection and (B) 90 matched-patients were compared and statistically analyzed. Intergroup comparison of binary variables was performed via Fisher's exact test. Intergroup comparison of continuous variables was achieved using unpaired t -tests. All reported p values are 2-sided and p values <.05 were regarded as statistically significant. RESULTS No statistically significant differences were noted for baseline characteristics including age, sex, diagnoses, procedures, and co-morbidities. There were no statistically significant intergroup differences in operative data such as operative time and operated levels. the HIV-infected patient group had higher rates of 30-day readmission (11.1% vs. 2.2%, P=.04), one-year surgical site infectious complication (13.3% vs. 3.3%, P=.06), and one-year pseudoarthrosis (17.8% vs. 4.4%, P=.02) as well as longer hospital stay (6.8days vs. 4.6days, p<.01) when compared with the control matched-cohort. Our post-hoc analysis only on 45 HIV-infected patients revealed that while HIV-1 RNA copy number with any cut-off values failed to predict 90-day medical complication rates, the cut-off value of CD4 absolute count <200/uL at the most recent preoperative encounter allowed us to stratify them into the two groups with regards to 90-day medical complication rates with statistical significance (44.4% (CD4<200) vs. 11.4% (CD4≥200), P=.04). CONCLUSIONS Spinal surgery in HIV-infected patients was associated with worse short- and long-term clinical outcomes, including higher rates of 30-day readmission, one-year infectious complication rate, and one-year pseudoarthrosis rate. Furthermore, CD4 absolute count may have some role in preoperative risk stratification. These results warrant further investigation of this cohort on multicenter, prospective basis, which should facilitate better patient selection for spine surgery and detailed informed consent, thereby potentially benefitting patients with HIV infection in the future. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Solid organ transplant is the mainstay of treatment for a wide variety of several end-stage organ diseases. The number of patients who will benefit from it is expected to increase due to improvement in distribution system for organs from donors, the discovery of novel immunosuppressive treatment/regimens, and better per- and post-operative management of these patients in general. Hence, an increasing number of these patients are becoming reasonable candidates for subsequent, elective surgeries such as spine surgery. Even though these patients are considered to be a high-risk group for surgery generally, clinical outcomes of spine surgery in patients with solid organ transplantation are not well-documented in the current literature partly due to its substantially rare incidence. Furthermore, prolonged use of steroids as well as immunosuppressant such as cyclosporine is associated with a decrease in bone mineral density. Thus, these outcome data might be of particular importance to consider surgical options for this high-risk cohort and inform them of specific risks and complications associated with spinal surgery after organ transplantation. PURPOSE Summarize clinical outcomes of spine surgery in solid organ recipients, such as readmission rate, infectious complications, and mortality, to facilitate clinical decision-making processes for this specific cohort. STUDY DESIGN/SETTING Retrospective, single-center, propensity-matched cohort. PATIENT SAMPLE Patients who underwent spine surgery at a single institution with previous history of solid organ transplantation were included and compared with a matched-cohort without solid organ transplantation. OUTCOME MEASURES Thirty-day readmission rate, 90-day medical complication rate, one-year infectious complication rate, one-year mortality, and functional outcomes such as ambulatory status, which was rated on a four-point scale (4, independently ambulatory; 3, requiring a cane; 2, requiring a walker; and 1, wheelchair bound). METHODS Single-center, retrospective data review from 2010 to 2016 yielded a total of 4,968 patients who underwent spine surgery. Amongst those, 28 patients had a previous history of solid organ transplantation. Patients from the database were propensity-matched for age, sex, body mass index (BMI), smoking status, diagnoses, procedures, co-morbidities other than diseases which had prompted organ transplantation at 1:2 ratio, which yielded 56 matched-patients. Clinical outcomes of (A) 28 patients with organ transplantation and (B) 56 matched-patients were compared and statistically analyzed. Intergroup comparison of binary variables was performed via Fisher's exact test. Intergroup comparison of continuous variables was achieved using unpaired t -tests. All reported p values are 2-sided and p values <.05 were regarded as statistically significant. RESULTS Baseline characteristics including age, sex, BMI, smoking, diagnoses, procedures, and co-morbidities (ASA scale) were similar between the two groups with no statistically significant difference, which validated our matching methods. There were no statistically significant intergroup differences in operative data such as operative time, estimated blood loss, operated levels, and use of bone morphogenetic protein-2. In terms of functional outcomes, postoperative improvement in ambulatory status was comparable between the two groups (A) 16.7% vs. (B) 18.1%, p>.99). However, the organ-recipient group resulted in longer hospital stays (A) 7.2days vs. (B) 4.3days, p<.01), higher rates of 30-day readmission (A) 14.3% vs. (B) 7.1%, P=.04), 90-day medical complication (A) 42.8% vs. (B) 17.9%, P=.02), one-year infectious complication (A) 14.3% vs. (B) 3.6%, P=.09), one-year reoperation (A) 14.3% vs. (B) 3.6%, P=.09) as compared with the control matched-cohort. CONCLUSIONS Spinal surgery after solid organ transplantation resulted in substantially increased complication rates when compared with the matched-control group, while other variables such as baseline characteristics, operative data, and functional outcomes were similar between the two groups. Careful patient selection, meticulous perioperative care, and thorough informed consent of potential complications would be imperative when performing spine surgery on this cohort. [ABSTRACT FROM AUTHOR]

Pedicle screws (PSs) are routinely used for stabilization to enhance fusion in a variety of spinal diseases. Although the accuracy of different PS placement methods has been previously reported, most of these studies have been limited to 1 or 2 techniques. The purpose was to determine the current accuracy of PS placement among 4 modalities of PS insertion (freehand [FH], fluoroscopy-assisted [FA], computed tomography navigation–guided [CTNav], and robot-assisted [RA]) and analyze variables associated with screw misplacement. A systematic review was performed of peer-reviewed articles reporting PS accuracy of 1 technique from January 1990 to June 2018. Accuracy of PS placement, PS insertion technique, and pedicle breach (PB) data were collected. A meta-analysis was performed to estimate the overall pooled (OP) rates of PS accuracy as a primary outcome, stratified by screw insertion techniques. Potential determinants were analyzed via meta-regression analyses. Seventy-eight studies with 7858 patients, 51,161 PSs, and 3614 cortical PBs were included. CTNav showed the highest PS placement accuracy compared with other techniques: OP accuracy rates were 95.5%, 93.1%, 91.5%, and 90.5%, via CTNav, FH, FA, and RA techniques, respectively. RA and CTNav were associated with the highest PS accuracy in the thoracic spine, compared with FH. The OP data show that CTNav has the highest PS accuracy rates. Thoracic PSs were associated with lower accuracy rates; however, RA showed fewer breaches in the thoracic spine compared with FH and FA. Given the heterogeneity among studies, further standardized and comparative investigations are required to confirm our findings. [ABSTRACT FROM AUTHOR]