The Use of Bone Morphogenetic Protein 2 (BMP-2) in Spine Surgery Is It Valuable?

BACKGROUND: Bone morphogenetic protein 2 (BMP-2) is one of the most widely used biologics in spine surgery. Its osteoinductive properties have been shown since its inception to improve fusion rates. Despite the positive effects on promoting fusion, there remains concerns regarding the significant costs associated with its use. The goal of this review was to investigate the value of BMP-2 in spine surgery. METHODS: A literature search was performed on various studies that report on the cost effectiveness and the value of BMP-2 in spine surgery. The value of BMP-2 was analyzed in two distinct settings: comparison to the gold standard iliac crest autograft and demineralized bone matrix. The value of BMP-2 was further analyzed in the setting of spinal deformity surgery. RESULTS: The findings of our review determined that BMP-2 offers significant improvement in outcomes related to improvement of fusion rates and minimization of pseudoarthrosis and reoperations related to pseudoarthrosis and donor site morbidity from harvesting iliac crest bone graft. However, BMP-2 has been found to be significantly more expensive in comparison to iliac crest bone graft and other bone graft substitutes, which detracts from its positive value. In deformity surgery, BMP-2 is associated with improvement in fusion rates as well as reducing the rate of reoperations and pseudoarthrosis. These positive outcomes, however, are associated with an expensive upfront cost for BMP-2. CONCLUSIONS: In terms of value, BMP-2 is associated with improvement in quality outcomes related to a reduction in pseudoarthrosis and reoperations. It also leads to improved outcomes with a reduction in donor site morbidity associated with iliac crest bone graft harvest. However, the value of BMP-2 is negatively affected because of its significant costs. As a result, higher expense thresholds are needed to increase quality adjusted life years in patients who receive BMP-2. Further research investigating ways to minimize the costs associated with BMP-2 use can further improve its value in spine surgery.

Impact of presenting patient characteristics on surgical complications and morbidity in early onset scoliosis.

This study sought to assess comorbidity profiles unique to early-onset-scoliosis (EOS) patients by employing cluster analytics and to determine the influence of isolated comorbidity clusters on perioperative complications, morbidity and mortality using a high powered administrative database. The KID database was queried for ICD-9 codes pertaining to congenital and idiopathic scoliosis from 2003, 2006, 2009, 2012. Patients <10 y/o (EOS group) were included. Demographics, incidence and comorbidity profiles were assessed. Comorbidity profiles were stratified by body systems (neurological, musculoskeletal, pulmonary, cardiovascular, renal). K-means cluster and descriptive analyses elucidated incidence and comorbidity relationships between frequently co-occurring comorbidities. Binary logistic regression models determined predictors of perioperative complication development, mortality, and extended length-of-stay (≥75th percentile). 25,747 patients were included (Age: 4.34, Female: 52.1%, CCI: 0.64). Incidence was 8.9 per 100,000 annual discharges. 55.2% presented with pulmonary comorbidities, 48.7% musculoskeletal, 43.8% neurological, 18.6% cardiovascular, and 11.9% renal; 38% had concurrent neurological and pulmonary. Top inter-bodysystem clusters: Pulmonary disease (17.2%) with epilepsy (17.8%), pulmonary failure (12.2%), restrictive lung disease (10.5%), or microcephaly and quadriplegia (2.1%). Musculoskeletal comorbidities (48.7%) with renal and cardiovascular comorbidities (8.2%, OR: 7.9 [6.6-9.4], p < 0.001). Top intra-bodysystem clusters: Epilepsy (11.7%) with quadriplegia (25.8%) or microcephaly (20.5%). Regression analysis determined neurological and pulmonary clusters to have a higher odds of perioperative complication development (OR: 1.28 [1.19-1.37], p < 0.001) and mortality (OR: 2.05 [1.65-2.54], p < 0.001). Musculoskeletal with cardiovascular and renal anomalies had higher odds of mortality (OR: 1.72 [1.28-2.29], p < 0.001) and extLOS (OR: 2.83 [2.48-3.22], p < 0.001). EOS patients with musculoskeletal conditions were 7.9x more likely to have concurrent cardiovascular and renal anomalies. Clustered neurologic and pulmonary anomalies increased mortality risk by as much as 105%. These relationships may benefit pre-operative risk assessment for concurrent anomalies and adverse outcomes. Level of Evidence: III - Retrospective Prognostic Study.

Comparative Analysis of Two Transforaminal Lumbar Interbody Fusion Techniques: Open TLIF Versus Wiltse MIS TLIF.

STUDY DESIGN: A retrospective cohort study at a single institution. OBJECTIVE: The aim of this study was to analyze the perioperative and postoperative outcomes of patients who underwent open transforaminal lumbar interbody fusion (O-TLIF) and bilateral minimally invasive surgery (MIS) Wiltse approach TLIF (Wil-TLIF). SUMMARY OF BACKGROUND DATA: Several studies have compared open TLIF to MIS TLIF; however, comparing the techniques using a large cohort of one-level TLIFs has not been fully explored. METHODS: We reviewed the charts of patients undergoing a single-level primary posterior lumbar interbody fusion between 2012 and 2017. The cases were categorized as Open TLIF (traditional midline exposure including lateral exposure of transverse processes) or bilateral paramedian Wiltse TLIF approach. Differences between groups were assessed by t tests. RESULTS: Two hundred twenty-seven patients underwent one-level primary TLIF (116 O-TLIF, 111 Wil-TLIF). There was no difference in age, gender, American Society of Anesthesiologists (ASA), or body mass index (BMI) between groups. Wil-TLIF had the lowest estimated blood loss (EBL; 197 vs. 499 mL O-TLIF, P ≤ 0.001), length of stay (LOS; 2.7 vs. 3.6 days O-TLIF, P ≤ 0.001), overall complication rate (12% vs. 24% O-TLIF, P = 0.015), minor complication rate (7% vs. 16% O-TLIF, P = 0.049), and 90-day readmission rate (1% vs. 8% O-TLIF, P = 0.012). Wil-TLIF was associated with the higher fluoroscopy time (83 vs. 24 seconds O-TLIF, P ≤ 0.001). There was not a significant difference in operative time, intraoperative or neurological complications, extubation time, reoperation rate, or infection rate. CONCLUSION: In comparing Wiltse MIS TLIF to Open TLIF, the minimally invasive paramedian Wiltse approach demonstrated the lowest EBL, LOS, readmission rates, and complications, but longer fluoroscopy times when compared with the traditional open approach. LEVEL OF EVIDENCE: 3.

Incidence, trends, and associated risks of developmental hip dysplasia in patients with Early Onset and Adolescent Idiopathic Scoliosis.

INTRODUCTION: Early Onset and Adolescent Idiopathic Scoliosis, relatively common diagnoses (∼3% general population), have been associated with developmental dysplasia of the hip (DDH); a more rare spectrum of anomalies related to the abnormal development of acetabulum, proximal femur, and hip joint. To the best of our knowledge, no high powered investigations have been performed in an attempt to assess incidence and associated risks of DDH in scoliosis patients. METHODS: The KID database was queried for ICD-9 codes from 2003 to 2012 pertaining to EOS (Congenital and Idiopathic <10y/o) and AIS patients. Descriptive analysis assessed patient demographics and yearly trends in hip dysplasia rates. EOS and AIS patients with hip dysplasia were isolated, and incidence of hospital admissions for associated anomalies (osteonecrosis, osteoarthritis, recurrent hip dislocation, hip ankylosis) and hip arthroplasty (total + partial) were investigated. Univariate analysis of hip pathology determined significant predictors of hip arthroplasty. Binary logistic regression analysis was used to determine the relationship between these predictors. RESULTS: 111,827 scoliosis patients (EOS: 25,747; AIS: 77,183) were included. AIS patients were older (15.2 vs 4.3), more female (64.2% vs 52.1%), had a higher CCI (0.84 vs 0.64), and less racially diverse (all p < 0.001). The incidence of hip dysplasia was 1.4% for AIS patients and 3.9% for EOS patients (p < 0.001). Of the AIS (n = 1073) and EOS (n = 1005) patients with hip dysplasia, 0.3% (p > 0.05 between groups) developed hip osteonecrosis, 0% of patients were coded as having a hip labral tear, hip ankylosis, and 0.6% (EOS: 0.2%; AIS: 0.9%, p = 0.025) developed hip osteoarthritis. AIS patients were more likely to have recurrent hip dislocations (35.4% vs 17.0%, p < 0.001), and both groups had similar primary hip arthroplasty rates (6.7% vs 5.4%, p = 0.118) and revision hip arthroplasty rates (0% vs 0.4%, p = 0.053). Hip osteoarthritis (OR: 13.43[5.21-34.66], p=<0.001) and older age (OR: 1.039[1.007-1.073], p = 0.017) were the only significant predictors of hip arthroplasty (p=<.001). CONCLUSIONS: The incidence of hip dysplasia in EOS and AIS populations is higher than that of the general population. The rate of DDH was 3.9% and 1.8% for EOS and AIS, respectively. While the incidence of DDH is higher, associated anomalies of osteoarthritis, osteonecrosis, labral tears, and ankylosis appear to be a minimal risk for AIS and EOS patients with Hip Dysplasia.

Does aspirin administration increase perioperative morbidity in patients with cardiac stents undergoing spinal surgery?

STUDY DESIGN: Cohort. OBJECTIVE: To compare the perioperative morbidity of patients with cardiac stents after spine surgery who continue to take aspirin before and after the operation with a similar group of patients who preoperatively discontinued aspirin. SUMMARY OF BACKGROUND DATA: The preoperative discontinuation of anticoagulant therapy has been the standard of care for orthopedic surgical procedures. However, recent literature has demonstrated significant cardiac risk associated with aspirin withdrawal in patients with cardiac stents. Although it has recently been demonstrated that performing orthopedic surgery while continuing low-dose aspirin therapy seems to be safe, studies focused on spinal surgery have not yet been performed. Because of the risk of intraspinal bleeding and the serious consequences of subsequent epidural hematoma with associated spinal cord compression, spinal surgeons have been reluctant to operate on patients taking aspirin. METHODS: This institutional review board-approved study included 200 patients. Preoperative parameters and postoperative outcome measures were analyzed for 100 patients who underwent spinal surgery after the discontinuation of anticoagulation therapy and 100 patients who continued to take daily aspirin through the perioperative period. The primary outcome measure was serious bleeding-related postoperative complications such as spinal epidural hematoma. The operative time, intraoperative estimated blood loss, hospital length of stay, transfusion of blood products, and 30-day hospital readmission rates were also recorded and compared. RESULTS: The patients who continued taking aspirin in the perioperative period had a shorter hospital length of stay on average (4.1 ± 2.7 vs. 6.2 ± 5.8; P < 0.005), as well as a reduced operative time (210 ± 136 vs. 266 ± 143; P < 0.01), whereas there was no significant difference in the estimated blood loss (642 ± 905 vs. 697 ± 1187), the amount of blood products transfused, overall intra- and postoperative complication rate (8% vs. 11%), or 30-day hospital readmission rate (5% vs. 5%). No clinically significant spinal epidural hematomas were observed in either of the study groups. CONCLUSION: The current study has observed no appreciable increase in bleeding-related complication rates in patients with cardiac stents undergoing spine surgery while continuing to take aspirin compared with patients who discontinued aspirin prior to surgery. Although very large studies will be needed to determine whether aspirin administration results in a small complication rate increase, the current study provides evidence that perioperative aspirin therapy is relatively safe in patients undergoing spinal surgery. LEVEL OF EVIDENCE: 2.

Feasibility of a cost-effective, video analysis software-based mobility protocol for objective spine kinematics and gait metrics: a proof of concept study.

The purpose of this study was to investigate the potential of a high-throughput, easily implemented, cost-effective, video analysis software-based mobility protocol to quantify spine kinematics. This prospective cohort study of clinical biomechanics implemented 2-dimensional (2D) image processing at a tertiary-care academic institution. Ten healthy, able-bodied volunteers were recruited for 2D videography of gait and functional motion. The reliability of a 2D video analysis software program for gait and range of motion metrics was evaluated over 2 independent experimental sessions, assessing for inter-trial, inter-session, and inter-rater reliability. Healthy volunteers were evaluated for simple forward and side bending, rotation, treadmill stride length, and more complex seated-to-standing tasks. Based on established intraclass correlation coefficients, results indicated that reliability was considered good to excellent for simple forward and side bending, rotation, stride length, and more complex sit-to-standing tasks. In conclusion, a cost-effective, 2D, video analysis software-based mobility protocol represents a feasible and clinically useful approach for objective spine kinematics and gait metrics. As the complication rate of operative management in the setting of spinal deformity is weighed against functional performance and quality of life measures, an objective analysis tool in combination with an appropriate protocol will aid in clinical assessments and lead to an increased evidence base for management options and decision algorithms.

Postoperative spinal fusion care in pediatric patients: Co-management decreases length of stay.

BACKGROUND: Standardized pediatric hospitalist and orthopaedic co-management of spinal fusion patients may improve quality processes and outcomes. This approach has not been studied in a general academic center. OBJECTIVE: Estimate relative effects and feasibility of the interventions on quality outcomes, length of stay (LOS), catheter-acquired urinary tract infections (CAUTI), medication errors, and pain scores. DESIGN AND SETTING: Retrospective cohort using interrupted time series, analyzing data from 83 patients aged 5 to 18 years admitted for posterior spinal fusion (PSF) in 2009 (N = 27), 2010 (N = 28), and 2011 (N = 28) on a children's service at a general academic tertiary care center. INTERVENTIONS: Multimodal approach to standardizing pediatric PSF postoperative care with interdepartmental development of order sets, clinical care guidelines, and routine pediatric hospitalist co-management of all pediatric PSF patients. MEASUREMENTS: Chi-square analysis of order set use, guideline use measured by proxy medication and documentation data. ANOVA for comparison of CAUTI and medication error rate and multivariate linear regression of LOS and pain scores. RESULTS: Pediatric hospitalist co-management documentation increased from 64% to 80%. Guideline use increased from 40% to 79%, and order set use was < 15%. CAUTI and medication error ratios remained low. Adjusted mean LOS decreased by 0.8 days (p = 0.039, 95% CI 0.7, 1.1). Pain scores did not differ. CONCLUSION: Interdisciplinary, clinical guideline development and postoperative co-management significantly decreased hospital LOS in pediatric PSF patients. In a general academic medical center, this change may be attributed to a pediatric hospitalist academic team, a universal co-management process with well-communicated roles, and a pediatric hospital-based physician development of and adherence to standardized practice.

Outcomes and complications of the midline anterior approach 3 years after lumbar spine surgery.

Objective. The purpose of this study was to evaluate a new questionnaire to assess outcomes related to the midline anterior lumbar approach and to identify risk factors for negative patient responses. Methods. A retrospective review of 58 patients who underwent anterior lumbar surgery at a single institution for either degenerative disc disease or spondylolisthesis in 2009 was performed. The outcome measures included our newly developed Anterior Lumbar Surgery Questionnaire (ALSQ), ODI, and EQ-5D. Results. There were 58 patients available for followup, 27 women and 31 men. The average age at surgery was 50.8 years, with an average followup of 2.92 years. The average change in ODI was 34.94 (22.7) and EQ-5D was 0.28 (0.29). The rate of complications with the anterior approach was 10.3% and there was one male patient (3.2%) with retrograde ejaculation. Determination of the effectiveness of the new ALSQ revealed that it significantly correlated to the EQ-5D and ODI (P < 0.05). Smoking was associated with a negative response on thirteen questions. BMP use was not associated with a negative response on any sexual function questions. Conclusions. Our new Anterior Lumbar Surgery Questionnaire determines patient perceived complications related to the midline anterior lumbar surgical approach.

Revision of a lumbar disc arthroplasty following late infection.

Anterior removal of a lumbar total disc replacement implant is often a very technically demanding procedure. The anterior retroperitoneal anatomy is prone to scarring, limiting remobilization and making a direct anterior exposure above the L5-S1 level difficult if not impossible to achieve safely. Anterolateral approach strategies can be more safely achieved at L4-L5 and above, but may require vertebral osteotomy in order to remove a keeled prosthesis. Successful conversion to a fusion with implant removal can be achieved, even when osteotomy is needed for implant removal. This Grand Rounds case presentation involves an unusual late retroperitoneal abscess following two-level TDR with direct extension to one of the implants, and the subsequent nonoperative and operative management. Removal of a well-fixed keeled implant at the L4-L5 level following nonoperative treatment of a surrounding retroperitoneal abscess and conversion to fusion represents close to, if not a 'worst-case' scenario for revision TDR. However, with proper preoperative planning and surgical experience, a safe and successful procedure can be the end result.

Allograft versus no graft with a posterior multisegmented hook system for the treatment of idiopathic scoliosis.

STUDY DESIGN: A prospective, randomized study. OBJECTIVE: To compare the clinical results of posterior spinal fusion (PSF) with allograft augmentation versus no graft for patients with adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The use of allograft has become a standard means of augmenting a PSF. Many studies have shown equal rates of fusion when comparing allograft with autogenous iliac crest. There have been no studies to directly compare the results obtained with allograft with those achieved without the use of any bone graft at all. METHODS: Ninety-one patients with AIS were randomized into two treatment groups. Seventy-six patients had greater than 2-year follow-up and are included in this review. The Allograft Group consisted of 37 patients who underwent a standard PSF using a multisegmented hook-screw and rod system with the use of corticocancellous allograft for augmentation. The No Graft Group included 39 patients with AIS who underwent the same procedure without any bone graft. All autogenous bone resulting from a thoracoplasty and any local bone (for example, that removed from spinous processes) was discarded in both groups. Patients with at least 2 years of radiographic and clinical follow-up were evaluated using established criteria for possible or definite pseudarthrosis. Treatment groups were similar with respect to age, preoperative deformity, and correction obtained. RESULTS: The overall definitive pseudarthrosis rate for this study was 1.3% (1 of 76 patients). The 1 patient with pseudarthrosis was in the Allograft Group (1 of 37, or 2.7%, P = 0.98 as defined by our criteria), versus none of 39 in the No Graft Group. Two patients in each group (5.4% in the Allograft Group and 5.1% in the No Graft Group) met the radiographic criteria for possible pseudarthrosis. This establishes a P value of 0.65 comparing risk of possible pseudarthrosis in the two groups. CONCLUSION: Our results suggest that a PSF using newer-generation multisegmented hook-screw and rod systems can be successful with allograft and/or local bonegraft without the use of supplemental autogenous bone graft (from the iliac crest or ribs) in patients with AIS.