Posterior Spinal Fusion Procedures Research Articles

Clinical characteristics and risk factors of intracranial hemorrhage after spinal surgery.

Intracranial hemorrhage after spinal surgery is a rare and devastating complication. To investigate the economic burden, clinical characteristics, risk factors, and mechanisms of intracranial hemorrhage after spinal surgery. A retrospective cohort study was conducted from January 1, 2015, to December 31, 2022. Patients aged ≥ 18 years, who had undergone spinal surgery were included. Intracranial hemorrhage patients were selected after spinal surgery during hospitalization. Based on the type of spinal surgery, patients with intracranial hemorrhage were randomly matched in a 1:5 ratio with control patients without intracranial hemorrhage. The patients' pre-, intra-, and post-operative data and clinical manifestations were recorded. A total of 24472 patients underwent spinal surgery. Six patients (3 males and 3 females, average age 71.3 years) developed intracranial hemorrhage after posterior spinal fusion procedures, with an incidence of 0.025% (6/24472). The prevailing type of intracranial hemorrhage was cerebellar hemorrhage. Two patients had a poor clinical outcome. Based on the type of surgery, 30 control patients were randomly matched in 1:5 ratio. The intracranial hemorrhage group showed significant differences compared with the control group with regard to age (71.33 ± 7.45 years vs 58.39 ± 8.07 years, P = 0.001), previous history of cerebrovascular disease (50% vs 6.7%, P = 0.024), spinal dura mater injury (50% vs 3.3%, P = 0.010), hospital expenses (RMB 242119.1 ± 87610.0 vs RMB 96290.7 ± 32029.9, P = 0.009), and discharge activity daily living score (40.00 ± 25.88 vs 75.40 ± 18.29, P = 0.019). The incidence of intracranial hemorrhage after spinal surgery was extremely low, with poor clinical outcomes. Patient age, previous stroke history, and dura mater damage were possible risk factors. It is suggested that spinal dura mater injury should be avoided during surgery in high-risk patients.

Examining impact forces during posterior spinal fusion to implement in a novel physics-driven virtual reality surgical simulator.

This study aims to understand the impact forces that surgeons apply to the human spine during a posterior spinal fusion procedure towards the development of a novel spine surgical simulator for training medical residents. The foci of this study are impact forces during graft placement and spinal interbody cage insertion. This study examined the lumbar intervertebral discs of two male cadaveric specimens. Impact forces were collected during graft and spinal cage insertion over multiple levels. An impulse hammer and a camera were used to collect impact forces and displacements, respectively. The results demonstrated a logarithmic relationship between impact forces and cumulative displacement during graft placement. This was also observed between cumulative displacement and number of impacts during spinal cage insertion. A linear relationship was observed for the impact forces and number of impacts during graft placement. Results suggest that surgeons rely on the feedback experienced from impact forces during graft insertion to gauge the amount of graft that was placed in a specific area of the disc. Impact forces during cage insertion provide information about any encountered obstacles. When developing surgical simulators, designing the force feedback system should require modelling these behaviors to effectively impart corresponding skills on a trainee.

Projections From Surgical Use Models in Germany Suggest a Rising Number of Spinal Fusions in Patients 75 Years and Older Will Challenge Healthcare Systems Worldwide.

Spinal fusion is a well-established procedure in the treatment of degenerative spinal diseases. Previous research shows that the use of this operative treatment has been growing in recent decades in industrialized countries and has become one of the most cost-intensive surgical procedures. It seems that in some countries such as Germany-with its large, industrialized, European population-this increase is mainly driven by demographic changes with low fertility rates, increasing life expectancy, and an aging population. Based on current projections, however, Germany faces a population trend that many other countries are likely to follow within a few decades. An increasingly shrinking and aging working population may eventually put the healthcare system under enormous pressure, with greater demands for spinal fusions and associated higher costs. Thus, we aimed to provide reliable projections regarding the future demand for posterior spinal fusion procedures including age- and gender-related trends up to 2060, which will be necessary for future resource planning and possible improvements in actual treatment strategies. (1) How is the use of posterior spinal fusions in Germany expected to change from 2019 through 2060, if currents trends continue? (2) How is the use of posterior spinal fusions in Germany expected to change depending on patients' age and gender during this time period? Comprehensive nationwide data provided by the Federal Statistical Office, the official institution for documenting all data on operations and procedures performed in Germany, were used to quantify posterior spinal fusion rates as a function of calendar year, age, and gender. Because there is a lack of evidence regarding future trends in the use of posterior spinal fusions, an autoregressive integrated moving average model on historical procedure rates from 2005 to 2019 in relation to official population projections from 2020 to 2060 was chosen to forecast future absolute numbers and incidence rates of this procedure in Germany. Long-term forecasting is more prone to unexpected disruptions than forecasting over short-term periods; however, longer spans facilitate estimates of how trends may challenge future healthcare systems if those trends continue, and thus are useful for research and planning. The incidence rate of posterior spinal fusion was projected to increase by approximately 83% (95% CI 28% to 139%) to 102% per 100,000 inhabitants (95% CI 71% to 133%) in 2060, with a 1.3-fold higher rate of women undergoing surgery in terms of absolute numbers. The highest increase identified by the model occurred in patients 75 years and older with 38,974 (95% CI 27,294 to 50,653) posterior spinal fusions in 2060, compared with 14,657 in 2019. This trend applied for both women and men, with a 246% (95% CI 138% to 355%) increase in the total number of posterior spinal fusions for women 75 years and older and a 296% (95% CI 222% to 370%) increase for men 75 years and older. At the same time, posterior spinal fusions in all age groups younger than 55 years were projected to follow a constant or even negative trend up to 2060. Our findings suggest that increasing use of posterior spinal fusion, particularly in patients 75 years and older, will challenge healthcare systems worldwide if current trends persist. This study may serve as a model for many other industrialized countries facing similar demographic and procedure-specific developments in the future. This emphasizes the need to focus on frailty research as well as appropriate financial and human resource management. Effective perioperative medical management, multidisciplinary treatment, and interinstitutional protocols are warranted, especially in older patients as we attempt to manage these trends in the future. Level III, economic and decision analysis.

Nomogram for predicting the distal adding-on phenomenon in severe and rigid scoliosis.

The distal adding-on phenomenon has attracted extensive discussion in the field of spine surgery due to the continual occurrence after scoliosis correction. Previous work has mainly focused on adolescent idiopathic scoliosis (AIS), and a relatively high number of theories for the mechanism of the distal adding-on phenomenon has been proposed for these kinds of patients. Severe and rigid scoliosis, as a special disease form, has a unique etiology, clinical manifestations and internal mechanisms distinct from those of AIS. Given the uniqueness of this disease, the mechanism and causes of the distal adding-on phenomenon have been infrequently studied in depth. To define clinical and radiological factors associated with distal adding-on in patients with severe and rigid scoliosis. Radiographic parameters and demographic data of patients with severe and rigid scoliosis were evaluated preoperatively, after posterior instrumentation and fusion surgery, and at the final follow-up via radiographs. According to the appearance of distal adding-on at the final follow-up, the patients were grouped into the Adding-on and the Non-adding-on groups. Various radiological parameters were analyzed in stepwise multivariate logistic regression to identify the variables associated with distal adding-on, which were then incorporated into a nomogram. The predictive performance and calibration of the nomograms for distal adding-on were assessed using C statistics and calibration plots. 93 patients (21 in the Adding-on and 72 in the Non-adding-on group) were included. The incidence of distal adding-on was 22.6%. The variables associated with distal adding-on were the anterior release, posterior internal distraction, and later posterior spinal fusion (IP) procedure, the posterior vertebral column resection and posterior spinal fusion (PVCR) procedure, postoperative apical vertebral translation (Post-AVT) and preoperative slope of the line linking the pedicles on the concave side of the upper- and lower-end vertebrae (Tan α). Combining these factors, the nomogram achieved a concordance index of 0.92 in predicting distal adding-on and had well-fitted calibration curves. For patient with a negative Tanα in severe and rigid scoliosis, the risk of distal adding-on tended to increase, and it is recommended to give priority to IP or PVCR. In the final correction, a smaller Post-AVT should not be pursued excessively.

Intraoperative Hypotension Is Not Correlated With Acute Kidney Injury During Spinal Fusion Surgery

Intraoperative hypotension (IOH) has been found to be associated with organ damage, including cardiac injury and acute kidney injury (AKI). However, to our knowledge, this relationship has not been studied in a neurosurgery-specific patient population. In this report, we review our institutional experience to understand the magnitude of association between IOH in spinal fusion operations and incidence of postoperative AKI. This retrospective cohort study included 910 patients who underwent posterior spinal fusion procedures performed in the prone position. Intraoperative variables collected and analyzed include minute-by-minute mean arterial pressure (MAP) from an arterial catheter, intermittent blood pressure cuff readings, volume of administered intravenous fluids, urine output, and all relevant vitals and administered medications. The electronic medical record was queried for additional patient data. IOH was defined as MAP <65 mm Hg for greater than 10 minutes. The primary endpoints of the study were presence and staging of AKI ( [Kidney Disease: Improving Global Outcomes] consensus classification), postoperative ileus, and postoperative troponin leak. Using a partial correlation analysis, no association was found between IOH metrics (IOH occurrence, IOH duration >10 minutes, and total IOH time) and any outcome metrics, including AKI, except for vasopressor usage and estimated blood loss. Patient age at surgery was not associated with any outcome variables. The lack of association between IOH and AKI contrasts with existing literature; this could be due to underlying differences in our patient population or could highlight a more complex relationship between IOH and AKI than previously understood. Occurrence and duration of IOH were not associated with AKI, postoperative ileus, troponin leak, length of stay, or any other major outcome variables in spinal fusion patients. These findings depart from previous literature showing a correlation between IOH and AKI and provide level 3 evidence clinically relevant to spinal surgery. Further research is needed to better understand the exact nature of this relationship.

Application of the ‘Surgical GPS’ to posterior spinal fusion procedures for scoliosis correction

ABSTRACT Scoliotic deformity correction is usually addressed with a posterior spinal fusion (PSF) approach. PSF operations are significantly invasive but can become safer and more efficient by reducing the number of ligament releases performed. However, PSF pre-operative planning to lessen ligament releases is constrained by current diagnostic imaging, which struggles with soft tissue localization, causing ligament release minimisation to be indeterminable. Patient-specific meshes that encompass vertebrae, intervertebral disks, ligaments, and other soft tissue may more accurately guide these pre-operative planning studies as well as intra-operative, computer-assisted surgery (CAS) systems supporting deformity correction. Further, merging physician-designated anatomical landmarks and pre-existing surgical ontologies into a resource description framework (RDF) format permits real-time, CAS guidance accommodating countless surgical workflows. By combining RDF-driven CAS guidance and patient-specific meshes, preoperative and intraoperative support of PSF procedures can be achieved at an individualised level. This study presents an early implementation of this combination, as the ‘Surgical GPS’.

Anaphylaxis after injecting a hemostatic agent containing gelatin into vertebral bone under pressure-a warning.

Case series. The use of topical hemostatic agents is common in spinal deformity surgery. While beneficial, emerging case data shows gelatin-containing agents causing intra-operative complications. We present two patients who developed anaphylaxis after injection of these gelatin-containing hemostatic agents into the vertebral body using manual pressure. In the literature, while anaphylactic reactions associated with the use of animal-derived gelatin has been implicated; the risk of injecting these products into the closed vascular cavity of the vertebral body with subsequent embolization into systemic circulation bears emphasis. This report is to meant to make the surgical team aware of the risks of injecting hemostatic agents using manual pressure into the vertebral body and to highlight a plausible mechanism for the phenomenon. Two children with spinal deformity undergoing posterior spinal fusion procedures with the use of gelatin-containing hemostatic agents injected into the vertebral body through the pedicle are described. Both patients had gelatin-containing hemostatic agent solution injected under manual pressure through the vertebral pedicle to prevent excessive bleeding. Anaphylaxis occurred soon thereafter, resulting in emergent cessation of the surgery and initiation of medical resuscitation. In both cases, tryptase levels obtained just after the event were elevated. Patients with an allergy to or prior history of exposure to zoologic products undergoing spine surgery may be at risk of anaphylaxis if the gelatin-containing hemostatic agent is injected under manual pressure into the closed space of the vertebral body. This allows rapid entry into the venous circulation. We recommend that the surgeon perform a thorough history of a patient's allergies and use extreme caution when injecting these topical hemostatic products into the vertebral body. IV.

Complications, Reoperations, and Mid-Term Outcomes Following Anterior Vertebral Body Tethering Versus Posterior Spinal Fusion

Background:Anterior vertebral body tethering (AVBT) is a growth-modulation technique theorized to correct adolescent idiopathic scoliosis (AIS) without the postoperative stiffness imposed by posterior spinal fusion. However, data are limited to small series examining short-term outcomes. To assess AVBT’s potential as a viable alternative to posterior spinal fusion (PSF), a comprehensive comparison is warranted. The purpose of this meta-analysis was to compare postoperative outcomes between patients with AIS undergoing PSF and AVBT. Our primary objective was to compare complication and reoperation rates at available follow-up times. Secondary objectives included comparing mid-term Scoliosis Research Society (SRS)-22 scores, and coronal and sagittal-plane Cobb angle corrections.Methods:We performed a systematic review of outcome studies following AVBT and/or PSF procedures. The inclusion criteria included the following: AVBT and/or PSF procedures; Lenke 1 or 2 curves; an age of 10 to 18 years for >90% of the patient population; <10% non-AIS scoliosis etiology; and follow-up of ≥1 year. A single-arm, random-effects meta-analysis was performed. Deformity corrections, complication and reoperation rates, and postoperative SRS-22 scores were recorded.Results:Ten AVBT studies (211 patients) and 14 PSF studies (1,069 patients) were included. The mean follow-up durations were similar for both groups. Pooled complication rates were 26% for AVBT versus 2% for PSF, and reoperation rates were 14.1% for AVBT versus 0.6% for PSF with nonoverlapping confidence intervals (CIs). The pooled reoperation rate among studies with follow-up times of ≥36 months was 24.7% in AVBT versus 1.8% in PSF. Deformity correction, clinical outcomes, and mid-term SRS-22 scores were similar.Conclusions:Our study showed greater rates of complications and reoperations with AVBT compared with PSF. Reoperation rates were significantly greater in AVBT studies with longer follow-up (≥36 months). Deformity correction, clinical outcomes, and mid-term SRS-22 scores were similar. While a potential fusionless treatment for AIS merits excitement, clinicians should consider AVBT with caution. Future long-term randomized prospective studies are needed.Level of Evidence:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

12. Health care costs and characteristics of spinal fusion patients receiving concentrated bone marrow aspirate (BMAC), iliac crest autograft or bone morphogenic protein (BMP) therapy: a retrospective cohort study utilizing administrative claims

BACKGROUND CONTEXT To aid in fusion, surgeons may choose to use a biologic or other grafting agent in posterior lumbar spinal fusion procedures. This study explored the differences in cost and a variety of outcomes of bone marrow aspirate concentrate (BMAC), iliac crest autogenous bone grafting (autograft) and recombinant human bone morphogenetic proteins (rhBMP) -2 and -7. Autograft complications include pain, risk of infection and donor morbidity. BMP drawbacks are high cost and at risk of stimulating too much bone growth. While BMAC has been shown to promote bone and soft tissue healing, possible risks include bleeding and infection or nerve damage. PURPOSE A market assessment was conducted to explore the clinical value of each product. The study also looked at patient demographics, outcomes, and cost across the grafting products. STUDY DESIGN/SETTING Retrospective administrative claims data from the Optum Commercial and Medicare Advantage affiliated claims dataset between January 1, 2016 and December 31, 2017. PATIENT SAMPLE The final study cohort consisted of 14,668 patients (BMAC: n=3,181; autograft: n=11,085; BMP: n=402) in the US. 84.5% (n=12,683) of patients had only 1 index procedure product and 97.2% (n=14,251) had a successful fusion. The majority of patients were aged 65+ (n=7,581 /52%), female (n=8,122 /55%), and received Medicare coverage (n=8,639 /59%). OUTCOME MEASURES Data on select patient demographic and clinical characteristic measures were collected, including Charlson Comorbidity Index (CCI) score and top AHRQ comorbidities. Inpatient and outpatient hospital costs, length of stay (LOS) and mean standardized cost per patient by procedure were among the data collected to drive the cost analysis. METHODS Patients with >= 1 a CPT code for a procedure of interest for autograft or BMAC or an ICD-10-PCS code for BMP of interest were identified during the study time period. Patients were indexed at admission date of MS-DRG involving first observed instance of a procedure of interest and required to have 6 months pre-and 12 months post-index continuous medical and pharmacy coverage. Data were analyzed using descriptive statistics. The mean differences in costs were assessed using Student's t-test for statistical significance. RESULTS The average length of stay (BMAC=3.6 days; autograft=3.8 days; BMP=4.3 days [p-value: BMAC vs autograft= CONCLUSIONS Data from this study showcases the cost savings and potential impact on health outcomes which can be incurred through the implementation of BMAC as a biologic in treating spine fusion patients. Given the rising cost of spinal fusion procedures performed annually in the US, further research should focus on evaluating the cost-effectiveness of the various procedures. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

The effects of varenicline on lumbar spinal fusion in a rat model

BACKGROUND CONTEXTSmoking is detrimental to obtaining a solid spinal fusion mass with previous studies demonstrating its association with pseudoarthrosis in patients undergoing spinal fusion. Varenicline is a pharmacologic adjunct used in smoking cessation which acts as a partial agonist of the same nicotinic receptors activated during tobacco use. However, no clinical or basic science studies to date have characterized if varenicline has negative effects on spinal fusion and bone healing by itself. PURPOSEOur study’s aim was to elucidate whether varenicline affects the frequency or quality of posterolateral spinal fusion in a rodent model at an endpoint of 12 weeks. STUDY DESIGNRandomized control trial. PATIENT SAMPLEFourteen male Lewis rats randomly separated into two experimental groups. OUTCOME MEASURESManual palpation of fusion segment, radiography, μCT imaging, and four-point bend. METHODSFourteen male Lewis rats were randomly separated into two experimental groups undergoing L4–L5 posterior spinal fusion procedure followed by daily subcutaneous injections of human dose varenicline or saline (control) for 12 weeks postsurgery. Spine samples were explanted, and fusion was determined via manual palpation of segments by two independent observers. High-resolution radiographs were obtained to evaluate bridging fusion mass. μCT imaging was performed to characterize fusion mass and consolidation. Lumbar spinal fusion units were tested in four-point bending to evaluate stiffness and peak load. Study funding sources include $5000 OREF Grant. There were no applicable financial relationships or conflicts of interest. RESULTSAt 3 months postsurgery, 12 out of 14 rats demonstrated lumbar spine fusion (86% fused) with no difference in fusion frequency between the varenicline and control groups as detected by manual palpation. High-resolution radiography revealed six out of seven rats (86%) having complete fusion in both groups. μCT showed no significant difference in bone mineral density or bone fraction volume between groups in the region of interest. Biomechanical testing demonstrated no significant different in the average stiffness or peak loads at the fusion site of the varenicline and control groups. CONCLUSIONBased on the results of our rat study, there is no indication that varenicline itself has a detrimental effect on the frequency and quality of spinal fusion.

PMD28 MINIMALLY INVASIVE VS OPEN SPINAL FUSION SURGERY: CLINICAL AND ECONOMIC POSTOPERATIVE EVALUATION IN A HEALTHCARE CLAIMS DATABASE USING MATCHED COHORTS

Minimally invasive spine surgery is increasingly performed in the United States and has been associated with favorable clinical and economic outcomes. This study was therefore designed to evaluate matched cohorts treated either with minimally-invasive or open procedures for their postoperative outcomes. All patients with posterior lumbar spinal fusion procedures in IBM® MarketScan® Commercial and Medicare Supplemental databases based on ICD-10 codes, and DRG = 460 (spinal fusion, except cervical, without major complication or comorbidities) and no prior surgery within 12 months of index and at least 90 days of continuous enrollment post index were identified from 2015-Q1 2018 and categorized as “Open” vs “MIS” based on ICD-10 procedure code. Demographic and comorbidities were collected for all patients. Patients from the MIS cohort were matched to the Open cohort using propensity score methodology (caliper: 0.2, method: nearest neighbor without replacement, model: logit, ratio: 3:1) on demographic (age, gender), Elixhauser Comorbidity Index, Functional Comorbidity Index and obesity status. Post-operative complication rates and cost of care were compared between groups using T test for parametric and Wilcoxon rank sum tests for nonparametric outcomes. A total of 83 MIS and 415 matched Open cases were identified. Whereas the 30-day rate of bleeding was higher in the MIS cohort (19% vs 8% in the open cohort), the Open cohort had greater all-cause readmission rates (4% vs 1% in the MIS cohort). The 90-day total cost of care, excluding cost of index surgery, was estimated at an average US$ 4,677 (SD: 12,403) in the Open vs. US$ 3,807 (SD: 8,547) in the MIS cohort. Patients treated with MIS had significantly lower overall mean post-operative costs and all-case readmission rates despite greater rates of 30-day bleeding that did not require readmissions, compared to matched patients treated with open surgery.

Friday, September 28, 2018 4:05 PM–5:05 PM abstracts: basic science of spinal fusion: 238. The effects of varenicline (Chantix) on lumbar spinal fusion in a rat model

BACKGROUND CONTEXT Smoking is detrimental to obtaining a solid spinal fusion mass with previous studies demonstrating that tobacco use is associated with pseudoarthrosis in patients undergoing spinal fusions. Additionally, smoking is an important predictor of increased dissatisfaction, decreased walking ability, increased pain medication use, and poorer quality of life scores in patients after spine surgery when compared to nonsmokers. Accordingly, physicians make significant efforts toward helping patients discontinue their use of nicotine products. Varenicline is a nonscheduled prescription medication that works as a partial agonist of nicotinic acetylcholine receptors, the same receptors activated during smoking and tobacco use, and is used as a pharmacologic adjunct to aid patients in smoking cessation. However, no clinical or basic science studies to date have characterized if varenicline has the same negative effects as nicotine on spinal fusion, consolidation, and bone healing. PURPOSE As a partial agonist of nicotine receptors, our study aimed to elucidate whether varenicline affects the rate or quality of spinal fusion. STUDY DESIGN/SETTING Manual, radiographic, and biomechanical testing. PATIENT SAMPLE A total of 14 Lewis rats undergoing L4-5 lumbar spinal fusion. OUTCOME MEASURES Gross motion, radiographic density, peak load, and stiffness of fusion mass METHODS According to our IACUC approved protocol, fourteen male Lewis rats underwent tail amputation to create an autogenous bone graft from the tailbone followed by a lumbar L4-5 posterior spinal fusion procedure. Postsurgery, rats were randomly separated into two experimental groups receiving either daily subcutaneous injections of human dose (1mg/kg daily in saline) varenicline or saline (placebo) for 12 weeks postsurgery. Spine samples were then explanted and fusion was determined via manual palpation of segments by two independent blinded observers. Radiographic analysis of fusion was performed via high-resolution radiographs evaluating bridging fusion mass. Rat lumbar spinal fusion units were then tested in 4-point bending to evaluate stiffness and peak load before failure. Comparisons were made between groups (significance at p RESULTS At three months postsurgery, twelve out of fourteen rats demonstrated lumbar spine fusion (86% fused) with no difference in fusion rate between the varenicline and control groups (6/7, 86%). Fusion rate as detected by manual palpation indicated no motion in the desired fusion segment. Findings were further supported with faxitron radiography demonstrating six out of seven rats (86%) having complete fusion consisting of contiguous transverse processes bilaterally at a single level in each of the varenicline and placebo control groups. Of the six successfully fused specimens, five from each group underwent successful biomechanical testing. The average stiffness at the fusion site of the varenicline group and control group was 49.2±17.5N/mm and 69.1±32.6N/mm, respectively (p=.271). The average peak load at the fusion site of the varenicline group and control group was 51.9±25.2N and 60.5±20.4N, respectively (p=.574). CONCLUSIONS Varenicline has no significant effect on the rate and quality of spinal fusions and remains an appropriate pharmaceutical adjunct for tobacco cessation in individuals undergoing spinal fusion.

The Role of Bone Scintigraphy in Determining Spinal Fusion after Spinal Stabilisation Surgery.

To evaluate the usefulness of bone scintigraphy in spinal fusion surgery. This retrospective study included 21 patients who had undergone previous anterior or posterior spinal fusion procedures, or both. Implant failure, fusion failure and adjacent segment disease were the evaluated pathological parameters. Scintigraphic data from all patients were evaluated with intraoperative observational data, radiological data and clinical data. Radiological evaluation revealed adjacent segment disease in 5 patients (23.8%), implant failure in 2 (9.5%), and fusion failure in 1 (4.8%). Scintigraphic evaluation of operating segments revealed pseudo-fusion in 3 patients (14.3%) and fusions in 18 (85.7%). Reoperations were performed in 9 patients (42.9%): in 5 (23.8%) because of adjacent segment disease, and in 4 (19.0%) because they requested removal of the implants. Two patients (9.5%) with implant failure did not undergo reoperation because their scintigraphic data were consistent with fusion and they were almost symptom free, with lower Visual Analogue Scale (VAS) scores. The VAS scores of the rest of the patients were significantly reduced after the reoperations (p < 0.001). Bone scintigraphy may be helpful for surgeons in planning appropriate surgical revision strategy by giving proper data about spinal fusion at least one year after the initial surgery.

Critical Airway Stenosis in an Adolescent Male With Pompe Disease and Thoracic Lordosis

An adolescent male with late-onset Pompe disease (glycogen storage disease type II) presented with a history of restrictive airway disease and a near-cardiorespiratory arrest during anesthesia for a liver biopsy initially thought to be due to bronchospasm. During a subsequent posterior spinal fusion procedure, he suffered cardiorespiratory arrest resulting in the procedure being aborted. Bronchoscopy performed shortly after resuscitation revealed an undiagnosed narrowing of the distal trachea and bronchi. This is the first description of a patient with late-onset Pompe disease with undiagnosed critical tracheal stenosis due to the progression of thoracic lordosis, which was ultimately relieved by posterior spinal fusion.

The Association Between Adjuvant Pain Medication Use and Outcomes Following Pediatric Spinal Fusion.

A comparative effectiveness database study. The aim of this study was to describe variation in use of adjuvant therapies for managing postoperative pain in in patients undergoing posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) and determine association between use of these therapies and patient outcomes. Variation in postoperative pain management for children undergoing PSF for AIS likely impacts outcomes. Minimal evidence exists to support strategies that most effectively minimize prolonged intravenous (IV) opioids and hospitalizations. We included patients aged 10 to 18 years discharged from one of 38 freestanding children's hospitals participating in a national database from December 1, 2012, to January 5, 2015, with ICD9 codes indicating scoliosis and PSF procedure. Use of ketorolac, gamma aminobutyric acid (GABA) analogues (GABAa), and benzodiazepines was compared across hospitals. Hierarchical logistic regression adjusting for confounders and accounting for clustering of patients within hospitals was used to estimate association between these therapies and odds of prolonged duration of IV opioids, prolonged length of stay (LOS), and early readmissions. Across hospitals, use of ketorolac and GABAa was highly variable and increased over time among 7349 subjects. Use of ketorolac was independently associated with significantly lower odds of prolonged LOS [odds ratio (OR) 0.75, 95% confidence interval (95% CI) 0.64-0.89] and prolonged duration of IV opioid (OR 0.84, 95% CI 0.73-0.98). GABAa use was significantly associated with decreased odds of prolonged IV opioid use (OR 0.63, 95% CI 0.53-0.75). Readmission rate at 30 days was 1.6% and most strongly associated with prolonged LOS. In this national cohort of children with AIS undergoing PSF, patients who received postoperative ketorolac or GABAa were less likely to have prolonged IV opioid exposure. Given the rapid increase in use of adjuvant therapies without strong evidence, resources should be devoted to multicenter trials in order to optimize effectiveness and outcomes. 3.

The impact of preoperative epidural injections on postoperative infection in lumbar fusion surgery.

OBJECTIVE Lumbar epidural steroid injections (LESIs) are performed for both diagnostic and therapeutic purposes for a variety of indications, including low-back pain, the leading cause of disability and expense due to work-related conditions in the US. The steroid agent used in epidural injections is reported to relieve nerve root inflammation, local ischemia, and resultant pain, but the injection may also have an adverse impact on spinal surgery performed thereafter. In particular, the possibility that preoperative epidural injections may increase the risk of surgical site infection after lumbar spinal fusion has been reported but has not been studied in detail. The goal of the present study was to use a large national insurance database to analyze the association of preoperative LESIs with surgical site infection after lumbar spinal fusion. METHODS A nationwide insurance database of patient records was used for this retrospective analysis. Current Procedural Terminology codes were used to query the database for patients who had undergone LESI and 1- or 2-level lumbar posterior spinal fusion procedures. The rate of postoperative infection after 1- or 2-level posterior spinal fusion was analyzed. These study patients were then divided into 3 separate cohorts: 1) lumbar spinal fusion performed within 1 month after LESI, 2) fusion performed between 1 and 3 months after LESI, and 3) fusion performed between 3 and 6 months after LESI. The study patients were compared with a control cohort of patients who underwent lumbar fusion without previous LESI. RESULTS The overall 3-month infection rate after lumbar spinal fusion procedure was 1.6% (1411 of 88,540 patients). The infection risk increased in patients who received LESI within 1 month (OR 2.6, p < 0.0001) or 1-3 months (OR 1.4, p = 0.0002) prior to surgery compared with controls. The infection risk was not significantly different from controls in patients who underwent lumbar fusion more than 3 months after LESI. CONCLUSIONS Lumbar spinal fusion performed within 3 months after LESI may be associated with an increased rate of postoperative infection. This association was not found when lumbar fusion was performed more than 3 months after LESI.

Association of low perioperative prealbumin level and surgical complications in long-segment spinal fusion patients: A retrospective cohort study

BackgroundSpinal surgery places significant physiological and nutritional burden on the patient. Complications are common and can impact long-term clinical outcomes. Therefore, it is important to identify factors associated with perioperative complications to potentially mitigate the lasting effects on patient outcomes. The significant impact of malnutrition on surgical outcomes has been well established; however, there is a paucity of data in the spine literature. Our objective was to evaluate perioperative prealbumin level in patients undergoing long-segment spinal fusion and its relationship to surgical outcomes and complication rates. Materials and methodsPatients who underwent long-segment (≥7) spinal fusions in whom a serum prealbumin level was obtained within 10 days of surgery were identified. Demographic, clinical, operative, and postoperative parameters were examined. Prealbumin levels were dichotomized using a threshold value of 11 mg/dL into low (<11 mg/dL) and high (≥11 mg/dL) groups. ResultsAmong the 47 patients identified, the mean prealbumin level was 12.2 mg/dL, with 20 patients (43%) in the low group and 27 (57%) in the high group. Patients with low prealbumin were more likely to undergo a longer fusion (11.6 vs. 9.1 levels, p = 0.003). They were also significantly more likely to develop an infectious complication than those in the high prealbumin group (50% vs. 15%, p = 0.012), most commonly urinary tract infection (9/14, 64%). There was no significant difference in rates of noninfectious complications between the two groups. Multiple binary logistic regression analysis revealed only low prealbumin was significantly associated with postoperative infection (OR 6.673, 95% CI 1.236–36.024). ConclusionsLow prealbumin levels were associated with higher rates of infections in patients undergoing long-segment posterior spinal fusion procedures. Further investigations are needed to better define this association and to determine whether effective interventions may be implemented in this subset of patients to attenuate this relationship.

Positioning Performance of Power and Manual Drivers in Posterior Spinal Fusion Procedures.

This work presents an analysis and comparison of the efficacy of two methods for pedicle screw placement during posterior spinal fusion surgery. A total of 100 screws (64 manual and 36 power driven), all placed utilizing a surgical navigation system, were analyzed and compared. Final screw placement was compared to initial surgical plans using the navigation system, and the final screw locations were analyzed on the basis of angular deviation from these planned trajectories as well as screw translation within a critical reference plane. The power driver was found to insignificantly decrease the resulting angular deviation of these pedicle screws with a mean deviation of 3.35 degrees compared to 3.44 degrees with the manual driver (p = 0.853). Conversely, the power driver was found to increase the translational distance in the critical region, with mean deviations of 2.45 mm for the power driver compared to 1.54 mm with the manual driver. The increase in translational deviation was significant (p = 0.002) indicating that there may be some loss in performance from the adoption of the power driver.

Malnutrition Predicts Infectious and Wound Complications Following Posterior Lumbar Spinal Fusion.

A retrospective review of data collected prospectively by the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). The aim of this study was to investigate the association between preoperative hypoalbuminemia, a marker for malnutrition, and complications during the 30 days following posterior lumbar fusion surgery. Malnutrition is a potentially modifiable risk factor that may contribute to complications following spinal surgery. Although prior studies have identified associations between malnutrition, delayed wound healing, and surgical site infection (SSI), the evidence for such a relationship within spine surgery is mixed. Patients who underwent posterior lumbar spinal fusion of one to three levels as part of the ACS-NSQIP were identified. Patients without preoperative serum albumin concentration were excluded. Outcomes were compared between patients with and without hypoalbuminemia (defined as serum albumin concentration <3.5 g/dL). All comparisons were adjusted for baseline differences between populations. Four thousand three hundred ten patients were included. The prevalence of hypoalbuminemia was 4.8%. In comparison to patients with normal albumin concentration, patients with hypoalbuminemia had a higher risk for occurrence of wound dehiscence [1.5% vs. 0.2%, adjusted relative risk (RR) = 5.8, P = 0.006], SSI (5.4% vs. 1.7%, adjusted RR = 2.3, P = 0.010), and urinary tract infection (5.4% vs. 1.5%, adjusted RR = 2.5, P = 0.005). Similarly, patients with hypoalbuminemia had a higher risk for unplanned hospital readmission within 30 days of surgery (11.7% vs. 5.4%, RR = 1.8, P < 0.001). Finally, patients with hypoalbuminemia had a longer mean inpatient stay (5.2 vs. 3.7 days, RR = 1.2, P < 0.001). The present study suggests that malnutrition is an independent risk factor for infectious and wound complications following posterior lumbar fusion. Malnutrition was also associated with an increased length of stay and readmission. Future studies should evaluate methods of correcting malnutrition before lumbar spinal surgery. Such efforts have the potential to meaningfully decrease the rates of adverse events following this procedure. 3.

Postoperative Complications Associated with rhBMP2 use in Posterior Lumbar Fusion

IntroductionThe growing number of degenerative conditions in aging population has contributed to the increased rates of lumbar posterior spinal fusion (PLF). While PLF has been shown to be effective for the treatment of various different spinal disorders, variations in surgical technique (such as bone graft used) for PLF have potential for different complication profiles. Human recombinant bone morphogenetic protein 2 (rhBMP2) is a bone graft material commonly used in the US to enhance spinal fusion rates after PLF. There are some reports of complications related to the use of rhBMP-2 in PLF arising from relatively small case series. Aim of our study was to quantify the frequency of various complications in elderly patients undergoing PLF with and without rhBMP2. Material and MethodsWe queried the orthopaedic subset of the Medicare database (PearlDiver) between 2005 and 2011. Current Procedure Terminology (CPT) codes were used to identify patients undergoing PLF procedures with and without rhBMP2, and International Statistical Classifcation of Diseases 9 (ICD-9) codes were used for complications. Complication and re-operation rates were analyzed within 1 year after the index procedure. Complications included: Acute Renal Failure, Deep Vein Thrombosis, Dural Tear, Hematoma, Heterotopic Ossification, Incision and Drainage, Myocardial Infarction or other cardiac complication, Nerve, Osteolysis, PLF Reoperation, Pneumonia, Pseudoarthrosis, Pulmonary Embolism, Radiculopathy, Respiratory Complications, Sepsis, Urinary Retention, Urinary Tract Infection, Mechanical (failure of other internal orthopedic device, implant, and graft) and Wound Complications. Chi-square analysis was used to calculate the complication differences between the groups. ResultsThere were 20,143 patients who underwent a PLF from 2005–2011, and 27% (5421) of those cases received rhBMP2, while 73% (14722) had the PLF procedure without it. The majority of PLF cases were female (62%) and 65–69 years of age (27%) patients. The overall complication rate was similar between the rhBMP2 and no-rhBMP2 groups, 78.8% and 76.4%, respectively. However, most of the complications had a significantly lower rate in the rhBMP2 group compared with the no-rhBMP2 group (Dural tear 2.2% versus 3%; Incision and Drainage 6.9% vs 7.8%; Myocardial Infraction 3.8% vs 4.4%; Nerve 1.1% vs 2%; Pulmonary Embolism 2.2% vs 2.8%; Radiculopathy 9.4% vs 11.1%; Sepsis 3% vs 3.9%; Wound 8.2% vs 9.6%, respectively). Complications that were in the rhBMP2 group were Mechanical 8% vs 6.2%; Pseudoarthrosis 3% vs 1.8%; Urinary retention 9.9% vs 8.7% (p < 0.05) and Urinary Tract Infection 30.30% vs 29.60%. Interestingly, heterotopic ossification, demonstrated less than 11 patients in both groups.