Usage of recombinant human bone morphogenetic protein in cervical spine procedures: analysis of the MarketScan longitudinal database

Usage Trends and Safety Profile of Recombinant Human Bone Morphogenetic Protein-2 for Spinal Column Tumor Surgery: A National Matched Cohort Analysis

STUDY DESIGN

Retrospective Cohort Analysis.

OBJECTIVE

The purpose of this study is to investigate national rates of rhBMP-2 utilization in spinal tumor surgery and examine its association with postoperative complications, revisions, and carcinogenicity.

METHODS

All patients diagnosed with primary or metastatic spinal tumors with subsequent surgical intervention involving a spinal fusion procedure were identified in PearlDiver. Patients were 1:1 matched into 2 cohorts according to rhBMP-2 usage. Postoperative complications and revisions were examined at 1 month, 3 months, 6 months, and 1 year after fusion. New cancer incidence following spinal tumor surgery was assessed until 5 years postoperatively.

RESULTS

A total of 11,198 patients underwent fusion surgery after resection of spinal tumors between 2005 and 2020, with 909 cases reporting the use of rhBMP-2 (8.1%). An annualized analysis revealed that the proportion of spine tumor fusion procedures utilizing rhBMP-2 has been significantly decreasing (R2 = .859, P < .001), with the most recent annual utilization rate at 1.1%. At least 3 months after surgery, significantly increased incidences of surgical site (11.4% vs 3.3%, P = .03) and systemic infections (8.1% vs 1.6%, P = .02) were observed in patients who underwent fusion with rhBMP-2. Across all time points, no significant differences were observed in survival, implant removal, revision rates, or new cancer diagnoses.

CONCLUSION

This analysis demonstrated significantly declining national utilization rates. Spinal tumor cases utilizing rhBMP-2 sustained greater rates of surgical site and systemic infections. rhBMP-2 usage did not significantly reduce the risk of mortality, implant failure, or reoperation.

The Evolution of Risk Assessment in Spine Surgery: A Narrative Review

BACKGROUND

Risk assessment is critically important in elective and high-risk interventions, particularly spine surgery. This narrative review describes the evolution of risk assessment from the earliest instruments focused on general surgical risk stratification, to more accurate and spine-specific risk calculators that quantified risk, to the current era of big data.

METHODS

The PubMed and SCOPUS databases were queried on October 11, 2023 using search terms to identify risk assessment tools (RATs) in spine surgery. A total of 108 manuscripts were included after screening with full-text review using the following inclusion criteria: 1) study population of adult spine surgical patients, 2) studies describing validation and subsequent performance of preoperative RATs, and 3) studies published in English.

RESULTS

Early RATs provided stratified patients into broad categories and allowed for improved communication between physicians. Subsequent risk calculators attempted to quantify risk by estimating general outcomes such as mortality, but then evolved to estimate spine-specific surgical complications. The integration of novel concepts such as invasiveness, frailty, genetic biomarkers, and sarcopenia led to the development of more sophisticated predictive models that estimate the risk of spine-specific complications and long-term outcomes.

CONCLUSIONS

RATs have undergone a transformative shift from generalized risk stratification to quantitative predictive models. The next generation of tools will likely involve integration of radiographic and genetic biomarkers, machine learning, and artificial intelligence to improve the accuracy of these models and better inform patients, surgeons, and payers.

Association Between Age-stratified Cohorts and Perioperative Complications and 30-day and 90-day Readmission in Patients Undergoing Single-level Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To assess perioperative complication rates and readmission rates after ACDF in a patient population of advanced age.

SUMMARY OF BACKGROUND DATA

Readmission rates after ACDF are important markers of surgical quality and, with recent shifts in reimbursement schedules, they are rapidly gaining weight in the determination of surgeon and hospital reimbursement.

METHODS

Patients 18 years of age and older who underwent elective single-level ACDF were identified in the National Readmissions Database (NRD) and stratified into 4 cohorts: 18-39 ("young"), 40-64 ("middle"), 65-74 ("senior"), and 75+ ("elderly") years of age. For each cohort, the perioperative complications, frequency of those complications, and number of patients with at least 1 readmission within 30 and 90 days of discharge were analyzed. χ 2 tests were used to calculate likelihood of complications and readmissions.

RESULTS

There were 1174 "elderly" patients in 2016, 1072 in 2017, and 1010 in 2018 who underwent ACDF. Their rate of any complication was 8.95%, 11.00%, and 13.47%, respectively ( P <0.0001), with dysphagia and acute posthemorrhagic anemia being the most common across all 3 years. They experienced complications at a greater frequency than their younger counterparts (15.80%, P <0.0001; 16.98%, P <0.0001; 21.68%, P <0.0001). They also required 30-day and 90-day readmission more frequently ( P <0.0001).

CONCLUSION

It has been well-established that advanced patient age brings greater risk of perioperative complications in ACDF surgery. What remains unsettled is the characterization of this age-complication relationship within specific age cohorts and how these complications inform patient hospital course. Our study provides an updated analysis of age-specific complications and readmission rates in ACDF patients. Orthopedic surgeons may account for the rise in complication and readmission rates in this population with the corresponding reduction in length and stay and consider this relationship before discharging elderly ACDF patients.

A BMP/Activin A Chimera Induces Posterolateral Spine Fusion in Nonhuman Primates at Lower Concentrations Than BMP-2

BACKGROUND

Supraphysiologic bone morphogenetic protein (BMP)-2 concentrations are required to induce spinal fusion. In this study, a BMP-2/BMP-6/activin A chimera (BV-265), optimized for BMP receptor binding, delivered in a recombinant human collagen:CDHA [calcium-deficient hydroxyapatite] porous composite matrix (CM) or bovine collagen:CDHA granule porous composite matrix (PCM), engineered for optimal BV-265 retention and guided tissue repair, was compared with BMP-2 delivered in a bovine absorbable collagen sponge (ACS) wrapped around a MASTERGRAFT Matrix (MM) ceramic-collagen rod (ACS:MM) in a nonhuman primate noninstrumented posterolateral fusion (PLF) model.

METHODS

In vivo retention of 125I-labeled-BV-265/CM or PCM was compared with 125I-labeled-BMP-2/ACS or BMP-2/buffer in a rat muscle pouch model using scintigraphy. Noninstrumented PLF was performed by implanting CM, BV-265/CM, BV-265/PCM, or BMP-2/ACS:MM across L3-L4 and L5-L6 or L3-L4-L5 decorticated transverse processes in 26 monkeys. Computed tomography (CT) images were acquired at 0, 4, 8, 12, and 24 weeks after surgery, where applicable. Manual palpation, μCT (microcomputed tomography) or nCT (nanocomputed tomography), and histological analysis were performed following euthanasia.

RESULTS

Retention of 125I-labeled-BV-265/CM was greater than BV-265/PCM, followed by BMP-2/ACS and BMP-2/buffer. The CM, 0.43 mg/cm3 BMP-2/ACS:MM, and 0.05 mg/cm3 BV-265/CM failed to generate PLFs. The 0.15-mg/cm3 BV-265/CM or 0.075-mg/cm3 BV-265/PCM combinations were partially effective. The 0.25-mg/cm3 BV-265/CM and 0.15 and 0.3-mg/cm3 BV-265/PCM combinations generated successful 2-level PLFs at 12 and 24 weeks.

CONCLUSIONS

BV-265/CM or PCM can induce fusion in a challenging nonhuman primate noninstrumented PLF model at substantially lower concentrations than BMP-2/ACS:MM.

CLINICAL RELEVANCE

BV-265/CM and PCM represent potential alternatives to induce PLF in humans at substantially lower concentrations than BMP-2/ACS:MM.

Safety and efficacy of low-dose rhBMP-2 use for anterior cervical fusion

OBJECTIVE

The use of recombinant human bone morphogenetic protein 2 (rhBMP-2) in routine anterior cervical fusion (ACF) is controversial. Early reports described high complication rates. A variety of dosing regimens ranging from 0.6 to 2.1 mg per level fused have been reported. The authors hypothesized that the high amounts of rhBMP-2 used in these studies led to the high complication rates observed; therefore, they set out to evaluate the safety and efficacy of low-dose rhBMP-2 for use in ACFs.

METHODS

Patient inclusion criteria were 1) age 18 to 70 years; 2) initial stand-alone ACF construct; 3) fusion augmentation with rhBMP-2; and 4) at least 1 year of radiographic follow-up. A successful fusion was defined by either 1) lateral flexion-extension radiographs with less than 1 mm of movement across the fused spinous processes, or 2) bone bridging at least half of the fusion area originally achieved by surgery on fine-cut CT. Patient demographics, perioperative data, and postoperative complications were recorded.

RESULTS

A total of 198 patients met the inclusion criteria and were included for analysis. Sixty-two patients (31%) were smokers. The median number of levels fused was 2 (IQR 1.25). The mean dose of rhBMP-2 was 0.50 ± 0.09 mg per level. Twenty-two (11%) patients experienced dysphagia. Eleven (6%) patients experienced cervical swelling. Two (1%) patients returned to the operating room (OR) for postoperative hematoma. One (0.5%) patient returned to the OR for seroma. Two (1%) patients experienced pseudarthrosis requiring a posterior fusion. Three (2%) patients experienced a new postoperative neurological deficit that had recovered by last the follow-up. Overall, 190 (96%) patients experienced solid arthrodesis over an average of 15 months of follow-up. There was no difference in fusion rates between patients who were either smokers or nonsmokers (p = 0.7073).

CONCLUSIONS

The use of low-dose rhBMP-2 safely and effectively augmented anterior cervical arthrodesis. The low-dose protocol assessed in this study appeared to significantly reduce complications associated with rhBMP-2 use in ACF compared with the literature. The authors have determined that using low-dose rhBMP-2 in patients who are smokers, those with multilevel ACFs, or others at high risk of developing pseudarthrosis is recommended.

Spine Surgery in the Octogenarian Population: A Comparison of Demographics, Surgical Approach, and Healthcare Utilization With the PearlDiver Database

Background

With the recent advances in technology and healthcare, increasing numbers of individuals over the age of 80 will require surgical intervention for spinal pathology. Given the risk of increased complications in the elderly, a limited number of spinal surgeries are performed on octogenarians every year. This makes it difficult to generalize the trends and outcomes of these surgeries to a greater population. This study attempts to understand the trends in the safety profile and healthcare utilization across the United States for octogenarians undergoing spinal fusion and/or decompression surgery for spinal stenosis and/or degenerative disease using the PearlDiver database.

Methodology

Patients who underwent fusion and/or decompression for stenosis and/or degenerative diseases were extracted using International Classification of Disease ninth and tenth revisions (ICD-9 prior to October 2015, ICD-10 after) from 2007 to 2016 in the PearlDiver database. Three comparative groups were considered: (1) primary fusion without concurrent decompression, (2) primary decompression with concurrent fusion, and (3) fusion with concurrent decompression. Outcomes of interest were patient characteristics, demographics, length of stay, surgery hospitalization payments, and discharge disposition. These outcomes were compared to patients over the age of 20 who also underwent spinal surgery.

Results

A total of 9,715 patients who underwent spinal surgery were identified in the search. Of the 9,139 patients, 503 were octogenarians and 73 were nonagenarians. Octogenarians and nonagenarians diagnosed with spinal stenosis were more likely to undergo decompression alone rather than fusion or both fusion and decompression (21 for both fusion and decompression; p < 0.0001). Patients diagnosed with both spinal stenosis and degeneration were more likely to undergo both fusion and decompression than fusion or decompression alone (239 for both, 208 for decompression alone, and 23 for fusion alone; p < 0.0001). No statistically significant difference was found in the percentage of patients discharged home following either fusion or decompression or both surgeries (p = 0.0737). The mean length of stay for patients in the 20-79-year age group was 2.79 days, whereas for the octogenarian and nonagenarian cohort it was 3.85 days. The index hospitalization pay for patients in the 20-79-year age group was $19,220, whereas for the octogenarians and nonagenarians cohort it was $15,091.

Conclusions

Patients over the age of 80 were more likely to undergo either a fusion procedure or a decompression procedure alone rather than both unless they were diagnosed with spinal degeneration. The PearlDiver database analysis indicates that the length of stay for octogenarians and nonagenarians is longer than that for patients in the 20-79-year age group, and that younger patients are more likely to be discharged earlier than patients over the age of 80. Moreover, we observed that the index hospitalization pay was higher for patients over the age of 20 than for octogenarians and nonagenarians in all cases except for a fusion procedure.

Complications of anterior cervical spine surgery: a systematic review of the literature

The anterior approach to the cervical spine is commonly utilized for a variety of degenerative, traumatic, neoplastic, and infectious indications. While many potential complications overlap with those of the posterior approach, the distinct anatomy of the anterior neck also presents a unique set of hazards. We performed a systematic review of the literature to assess the etiology, presentation, natural history, and management of these complications. Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a PubMed search was conducted to evaluate clinical studies and case reports of patients who suffered a complication of anterior cervical spine surgery. The search specifically included articles concerning adult human subjects, written in the English language, and published from 1989 to 2019. The PubMed search yielded 240 articles meeting our criteria. The overall rates of complications were as follows: dysphagia 5.3%, esophageal perforation 0.2%, recurrent laryngeal nerve palsy 1.3%, infection 1.2%, adjacent segment disease 8.1%, pseudarthrosis 2.0%, graft or hardware failure 2.1%, cerebrospinal fluid leak 0.5%, hematoma 1.0%, Horner syndrome 0.4%, C5 palsy 3.0%, vertebral artery injury 0.4%, and new or worsening neurological deficit 0.5%. Morbidity rates in anterior cervical spine surgery are low. Nevertheless, the unique anatomy of the anterior neck presents a wide variety of potential complications involving vascular, aerodigestive, neural, and osseous structures.

Exploratory meta-analysis on dose-related efficacy and complications of rhBMP-2 in anterior cervical discectomy and fusion: 1,539,021 cases from 2003 to 2017 studies

Background/Objective

Anterior cervical discectomy and fusion (ACDF), commonly using autogenous iliac bone graft may be limited by donor site availability, donor-site morbidity, lower fusion rate among specific patients and longer surgical time. Surgeons used rhBMP-2 as an alternative in order to fill these clinical needs. However, studies comparing with and without rhBMP-2 in ACDF have reported conflicting results on efficacy and complications. Therefore, the purpose of this article was to evaluate efficacy and complications through dose-related rhBMP-2 and surgical level-dependence in ACDF.

Methods

We comprehensively searched PubMed and the Cochrane Library and performed a systematic review and cumulative meta-analysis of all randomized controlled trials (RCTs), prospective and retrospective comparative studies assessing with and without rhBMP-2 treatments.

Results

1 RCTs, 4 prospective studies and 24 retrospective studies including a total of 1,539,021 cases were identified. Patients in ACDF with rhBMP-2 might benefit from significantly higher fusion rates than that in non-rhBMP-2, not only total value but also in 3 tiers of rhBMP-2 doses. It is worth noting that the low dose of rhBMP-2 (<0.7 mg/level) showed highest fusion rate among all rhBMP-2 doses. Patients in rhBMP-2 also experienced higher complication rate, dysphagia and wound infections than that in non-rhBMP-2. In 2-level ACDF, the fusion rate was significantly better in rhBMP-2 than non-rhBMP-2 but not for complication rate. Surgery operative time, lengths of hospital stay and neurologic symptoms did not differ significantly between two treatments.

Conclusions

rhBMP-2 chosen in ACDF offered higher fusion, but also higher complication rate with more dysphagia and wound infections than non-rhBMP-2. To gain the efficacy and safety, rhBMP-2 dosing recommendations for ACDF would be better < 0.7 mg/level. Moreover, rhBMP-2 may be an option to improve nonunion in high risk of multi-level ACDF.

The translational potential of this article

This article indicated that the product development of facilities used in ACDF, the dose of rhBMP-2 may be lower than 0.7 mg/level was enough to gain the good fusion rates. However, the complications were higher in patients used rhBMP-2, therefore the manufacturers should pay attention to mitigate such side effects.

An Absorbable Collagen Biomembrane Help Improve Swallowing Function After Anterior Cervical Spine Surgery

The objective of this study is to investigate the changes in swallowing function after using an absorbable collagen biomembrane during anterior cervical spine surgery (ACSS). A prospective controlled study of patients who underwent two-level anterior cervical decompression and fusion (ACDF) with a zero-profile implant or single-level anterior cervical corpectomy and fusion (ACCF) with cage and plate fixation was performed in our hospital from January 2016. An absorbable collagen biomembrane was used after suturing the prevertebral fascia in the experimental groups. The thickness of prevertebral soft tissue (PST) was measured on lateral X-rays to determine the extent of swelling. In addition, the Bazaz grading system and the Swallowing-Quality of Life (SWAL-QOL) survey were used to assess the swallowing function. A total of 100 patients were included with a follow-up of 12 months. Significant differences in PST swelling were found between the experimental groups and control groups at 3 months, 6 months, and 12 months postoperatively (P < 0.05). Patients in the experimental groups had significantly increased SWAL-QOL scores compared with patients in the control groups at 3 months and 6 months after surgery (P < 0.05). A significant difference in the total incidence of dysphagia was observed at 3 months postoperatively between the experimental groups and control groups (P < 0.05). The application of absorbable collagen biomembrane in ACSS can reduce the total incidence of dysphagia and improve swallowing function early after surgery.

Contained-Delivery Route and the Administration of Postoperative Steroids Following Anterior Cervical Spinal Fusion With Low-dose rhBMP-2 Reduces the Magnitude of Respiratory Compromise

STUDY DESIGN

Retrospective chart review of patients who underwent anterior cervical discectomy and fusion (ACDF) using low-dose recombinant human bone morphogenic protein (rhBMP)-2.

OBJECTIVE

Determine whether severity and incidence of respiratory complications after ACDF surgery are decreased when using a low-dose BMP-infused sponge within a constrained carrier and postoperative IV and oral steroids.

SUMMARY OF BACKGROUND DATA

Many physicians avoid using BMP in anterior cervical spine fusions because of concern for an increased incidence of dysphagia, significant prevertebral swelling, and airway edema compromise. Pilot studies have shown that the local application of steroids may decrease the incidence of postoperative airway edema and dysphagia. We performed a retrospective study to evaluate the safety of immediate postoperative tapered steroid use following low-dose rhBMP-2 completely contained inside either an allograft or PEEK cage in reducing the severity and incidence of respiratory complications following ACDF.

MATERIALS AND METHODS

Forty-seven patients between 33 and 74 years of age, undergoing 1-, 2-, 3-, or 4-level ACDFs augmented with a fraction of a small sponge of rhBMP-2 (0.525 mg/level) within an allograft or PEEK cage and prescribed IV and oral postoperative steroids between January 1, 2008 and November 1, 2016. The incidence of complications such as dyspnea, dysphagia, airway issues, edema ectopic bone osteolysis, radiculitis, and nonunion were collected using medical charts. Additional data regarding length of hospital stay and readmissions were also recorded.

RESULTS

No life-threatening respiratory events, such as prolonged intubation, re-intubation, or readmission for labored breathing, were observed. No complications referable to steroids such as delayed healing, uncontrollable blood sugar, or diabetes were encountered in this series.

CONCLUSIONS

This study provides evidence that a tapered dose of steroids and a contained delivery route significantly decreases postoperative respiratory compromise incidence and magnitude following anterior cervical spine fusion using low-dose rhBMP-2.

A Heparan Sulfate Device for the Regeneration of Osteochondral Defects

IMPACT STATEMENT

Repairing damaged joint cartilage remains a significant challenge. Treatment involving microfracture, tissue grafting, or cell therapy provides some benefit, but seldom regenerates lost articular cartilage. Providing a point-of-care solution that is cell and tissue free has the potential to transform orthopedic treatment for such cases. Glycosaminoglycans such as heparan sulfate (HS) are well suited for this purpose because they provide a matrix that enhances the prochondrogenic activities of growth factors normally found at sites of articular damage. In this study, we show the potential of a novel HS device, which is free of exogenous cells or growth factors, in regenerating osteochondral defects.

Insights Into Oropharyngeal Dysphagia From Administrative Data and Clinical Registries: A Literature Review

Purpose

The call for data-driven health care has been bolstered by the digitization of medical records, quality initiatives, and payment reform. Administrative databases and clinical registries are increasingly being used to study oropharyngeal dysphagia and to facilitate data-driven decision making. The objective of this work was to summarize key findings, etiologies studied, data sources used, study objectives, and quality of evidence of all original research articles that have investigated oropharyngeal dysphagia or aspiration pneumonia using administrative or clinical registry data to date.

Method

A literature search was completed in MEDLINE, Scopus, and Google Scholar (January 1, 1990, to February 1, 2017). Each study that met inclusion criteria was rated for quality of evidence on a 5-point scale.

Results

Eighty-four research articles were included in the final analysis (n = 221-1,649,871). Over the past 20 years, the number of new publications in this area has quintupled. Most of the administrative database and clinical registry studies of dysphagia have been retrospective cohort studies and cross-sectional studies and limited to quality of evidence levels of 3-4. In these studies, much has been learned about risk factors for dysphagia and pneumonia in defined populations and health care costs and usage. Little has been gleaned from these studies regarding swallowing physiology or dysphagia management.

Conclusions

Investigators are just beginning to develop the methods to study oropharyngeal dysphagia using administrative data and clinical registries. Future research is needed in all areas, from the fundamental issue of how to identify individuals with dysphagia with high sensitivity in these data sets to evaluating treatment effectiveness.

Supplemental Material

https://doi.org/10.23641/asha.6066515.

Trend of Spine Surgeries in the Outpatient Hospital Setting Versus Ambulatory Surgical Center

STUDY DESIGN

Retrospective database review.

OBJECTIVE

The aim of the present study was to examine how often spine surgery is being performed in an outpatient hospital setting versus a more "true" ambulatory setting, specifically ambulatory surgery centers (ASCs) in which admission and discharge are required on the same calendar day.

SUMMARY OF BACKGROUND DATA

Recent studies have assessed the safety, satisfactory clinical outcomes, and increasing utilization of both cervical and lumbar spinal surgeries performed in the outpatient setting. No studies have delineated between true ambulatory settings and outpatient hospitals when assessing the rates of these procedures.

METHODS

A retrospective review of the Truven Health Marketscan Research Databases was conducted for patients undergoing spine operations between 2003 and 2014. The frequency of each Common Procedural Terminology code was identified per year, and then categorized into each of "inpatient hospital," "outpatient hospital," or "ASC" in states that clearly define ASCs as facilities in which patients are discharged on the same calendar day of the operation, and do not stay overnight.

RESULTS

During the period between 2003 and 2014, the procedures that had the most dramatic increase as an outpatient hospital procedure included lumbar decompression laminotomy first level (18.7%-68.5%) and posterior cervical decompression laminectomy without facetectomy discectomy first level (0%-46.7%). ASC procedures had more modest increases during this time period with the most significant increases in lumbar decompression laminotomy first level (0.7%-10.6%) and posterior cervical decompression laminotomy first level (0%-23.4%).

CONCLUSION

"True" ambulatory surgeries are not increasing at the same rate as outpatient procedures with 23-hour observation capacity. Although prior studies have demonstrated the safety of outpatient spine surgery, one possible reason for this trend may be that surgeons feel that this safety may not be comparable to that of other outpatient procedures.

LEVEL OF EVIDENCE

3.

Clinical and Radiographic Outcomes in Patients Undergoing Single-level Anterior Cervical Arthrodesis: A Prospective Trial Comparing Allograft to a Reduced Dose of rhBMP-2

STUDY DESIGN

A prospective study with historical controls.

OBJECTIVES

To evaluate and compare the safety and effectiveness of recombinant human bone morphogenetic protein-2 (rhBMP-2) with allograft for anterior cervical discectomy and fusion (ACDF) in patients with symptomatic single-level cervical degenerative disk disease.

SUMMARY OF BACKGROUND DATA

rhBMP-2 is an osteoinductive protein that has been shown to induce fusion when used as an implant with a suitable carrier in spine surgery. However, some previous studies have shown rhBMP-2 use to be associated with a higher complication rate.

METHODS

Investigational patients (224) with single-level cervical degenerative disk disease underwent ACDF with rhBMP-2 at a dose of 0.6 or 1.05 mg and were compared with historical control patients (486) treated with allograft spacer and cervical plate.

RESULTS

At 24 months, improvement was significantly greater in the investigational group (37.1 points) than in the control group for Neck Disability Index (P=0.002) and arm pain (P=0.031). The overall neurological success rate was higher in the investigational group (P<0.001). Neck pain and general health status (SF-36 PCS and MCS) were similar. Fusion rate in the investigational group was higher than in the control group (99.4% vs. 87.2%, P=0.002).Cumulative adverse event rates at 24 months were similar; however, higher rates of dysphagia (P=0.001), local swelling (P=0.024), oropharyngeal pain (P=0.013), neck pain (P=0.019), and foraminal stenosis (P=0.002) were observed in the investigational group. Heterotopic ossification was also higher in the investigational group.

CONCLUSIONS

At doses of 0.6 or 1.05 mg in a PEEK interbody cage, rhBMP-2 was effective in inducing fusion and improving Neck Disability Index and arm pain in single-level ACDF patients; however, higher rates of certain adverse events were observed in the investigational group.

LEVEL OF EVIDENCE

Level 2.

Risk factors and preventative measures of early and persistent dysphagia after anterior cervical spine surgery: a systematic review

PURPOSE

To conduct a systematic review of literature to determine risk factors and preventative measures of early and persistent dysphagia after anterior cervical spine surgery (ACSS).

METHODS

On March 2017, we searched the database PubMed, Medline, EMBASE, the Cochrane library, Clinical key, Springer link and Wiley Online Library without time restriction using the term 'dysphagia', 'swallowing disorders', and 'anterior cervical spine surgery'. Selected papers were examined for the level of evidence by published guidelines as level I, level II, level III, level IV studies. We investigated risk factors and preventative measures of early or persistent dysphagia after ACSS from these papers.

RESULTS

The initial search yielded 515 citations. Fifty-nine of these studies met the inclusion and exclusion criteria. Three of them were level I evidence studies, 29 were level II evidence studies, 22 were level III evidence studies, and 3 were level IV evidence studies. Preventable risk factors included prolonged operative time, use of rhBMP, endotracheal tube cuff pressure, cervical plate type and position, dC2-C7 angle, psychiatric factors, tobacco usage, prevertebral soft tissue swelling, SLN or RLN palsy or injury of branches. Preventative measures included preoperative tracheal traction exercise, maintaining endotracheal tube cuff pressure at 20 mm Hg, avoiding routine use of rhBMP-2, use of zero-profile implant, use of Zephir plate, use of new cervical retractor, steroid application, avoiding prolonged operating time, avoiding overenlargement of cervical lordosis, decreasing surgical levels, ensuring knowledge of anatomy of superior laryngeal nerve and recurrent laryngeal nerve, to comfort always, patients quitting smoking and doctors ensuring improved skills. Unpreventable risk factors included age, gender, multilevel surgery, revision surgery, duration of preexisting pain, BMI, blood loss, upper levels, preoperative comorbidities and surgical type.

CONCLUSION

Adequate preoperative preparation of the patients including preoperative tracheal traction exercise and quitting smoking, proper preventative measures during surgery including maintaining endotracheal tube cuff pressure at 20 mm Hg, avoiding routine use of rhBMP-2, use of zero-profile implant, use of Zephir plate, use of new cervical retractor, steroid application, avoiding prolonged operating time, avoiding overenlargement of cervical lordosis and decreasing surgical levels, doctors ensuring knowledge of anatomy, improved surgical techniques and to comfort always are essential for preventing early and persistent dysphagia after ACSS.

The impact of hepatitis C virus infection on 90-day outcomes following major orthopaedic surgery: a propensity-matched analysis

INTRODUCTION

The impact of hepatitis C virus (HCV) infection on outcomes following major orthopaedic interventions, such as joint arthroplasty or spine surgery, has not been effectively studied in the past. Most prior studies are impaired by small samples, limited surveillance for adverse events, or the potential for selection bias to confound results. In this context, we sought to evaluate the impact of HCV infection on 90-day outcomes following joint arthroplasty or spine surgery using propensity-matched techniques.

MATERIALS AND METHODS

This study utilized 2006-2014 claims from TRICARE insurance. Adults who received spine surgical procedures, total knee and hip arthroplasty were identified. Covariates included demographic factors, a diagnosis of HCV and medical co-morbidities defined by International Classification of Disease-9th revision (ICD-9) code. Outcomes consisted of 30- and 90-day mortality, complications and readmission. A propensity score was used to balance the cohorts with logistic regression techniques employed to determine the influence of HCV infection on post-operative outcomes.

RESULTS

The propensity-matched cohort consisted of 2262 patients (1131 with and without HCV). Following logistic regression, patients with HCV were found to have increased odds of 30-day complications (OR 1.87; 95% CI 1.33, 2.64; p < 0.001), 90-day complications (OR 1.55; 95% CI 1.16, 2.08; p = 0.003) and 30-day readmission (OR 1.46; 95% CI 1.04, 2.05; p = 0.03).

CONCLUSION

HCV infection was found to increase the risk of complication and readmission following spine surgery and total joint arthroplasty. Patients should be counseled on their increased risk prior to surgery. Health systems that treat a higher percentage of patients with HCV need to consider the increased risk of complications and readmission when negotiating with insurance carriers.

Predicting complication risk in spine surgery: a prospective analysis of a novel risk assessment tool

OBJECTIVE The ability to assess the risk of adverse events based on known patient factors and comorbidities would provide more effective preoperative risk stratification. Present risk assessment in spine surgery is limited. An adverse event prediction tool was developed to predict the risk of complications after spine surgery and tested on a prospective patient cohort. METHODS The spinal Risk Assessment Tool (RAT), a novel instrument for the assessment of risk for patients undergoing spine surgery that was developed based on an administrative claims database, was prospectively applied to 246 patients undergoing 257 spinal procedures over a 3-month period. Prospectively collected data were used to compare the RAT to the Charlson Comorbidity Index (CCI) and the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator. Study end point was occurrence and type of complication after spine surgery. RESULTS The authors identified 69 patients (73 procedures) who experienced a complication over the prospective study period. Cardiac complications were most common (10.2%). Receiver operating characteristic (ROC) curves were calculated to compare complication outcomes using the different assessment tools. Area under the curve (AUC) analysis showed comparable predictive accuracy between the RAT and the ACS NSQIP calculator (0.670 [95% CI 0.60-0.74] in RAT, 0.669 [95% CI 0.60-0.74] in NSQIP). The CCI was not accurate in predicting complication occurrence (0.55 [95% CI 0.48-0.62]). The RAT produced mean probabilities of 34.6% for patients who had a complication and 24% for patients who did not (p = 0.0003). The generated predicted values were stratified into low, medium, and high rates. For the RAT, the predicted complication rate was 10.1% in the low-risk group (observed rate 12.8%), 21.9% in the medium-risk group (observed 31.8%), and 49.7% in the high-risk group (observed 41.2%). The ACS NSQIP calculator consistently produced complication predictions that underestimated complication occurrence: 3.4% in the low-risk group (observed 12.6%), 5.9% in the medium-risk group (observed 34.5%), and 12.5% in the high-risk group (observed 38.8%). The RAT was more accurate than the ACS NSQIP calculator (p = 0.0018). CONCLUSIONS While the RAT and ACS NSQIP calculator were both able to identify patients more likely to experience complications following spine surgery, both have substantial room for improvement. Risk stratification is feasible in spine surgery procedures; currently used measures have low accuracy.

Clinical application of bone morphogenetic proteins for bone healing: a systematic review

PURPOSE

This paper documents the existing evidence on bone morphogenetic proteins (BMPs) use for the treatment of bone fractures, non-union, and osteonecrosis, through a review of the clinical literature, underlying potential and limitations in terms of cost effectiveness and risk of complications.

METHODS

A systematic review was performed on the PubMed database using the following string: (bone morphogenetic proteins OR BMPs) and (bone repair OR bone regeneration) including papers from 2000 to 2016. The search focused on clinical trials dealing with BMPs application to favor bone regeneration in bone fractures, non-union, and osteonecrosis, in English language, with level of evidence I, II, III, and IV. Relevant data (type of study, number of patients, BMPs delivery material, dose, site, follow-up, outcome, and adverse events) were extracted and analyzed.

RESULTS

Forty-four articles met the inclusion criteria: 10 randomized controlled trials (RCTs), 7 comparative studies, 18 case series, and 9 case reports. rhBMP-2 was documented mainly for the treatment of fractures, and rhBMP-7 mainly for non-unions and osteonecrosis. Mixed results were found among RCTs and comparative papers: 11 reported positive results for BMPs augmentation, 3 obtained no significant effects, and 2 showed negative results. The only study comparing the two BMPs showed a better outcome with rhBMP-2 for non-union treatment.

CONCLUSION

Clinical evidence on BMPs use for the treatment of fractures, non-union, and osteonecrosis is still controversial, with the few available reports being mainly of low quality. While positive findings have been described in many studies, mixed results are still present in the literature in terms of efficacy and adverse events. The difficulties in drawing clear conclusions are also due to the studies heterogeneity, mainly in terms of different BMPs applied, with different concomitant treatments for each bone pathology. Therefore, further research with well-designed studies is needed in order to understand the real potential of this biological approach to favour bone healing.

Atlantoaxial Fusion: Sixteen Years of Epidemiology, Indications, and Complications in New York State

STUDY DESIGN

A retrospective state database analysis.

OBJECTIVE

The aim of this study was to describe the epidemiology and complications of as well as indications for primary isolated atlantoaxial fusion.

SUMMARY OF BACKGROUND DATA

Atlantoaxial fusion involves unique indications, techniques, and complications. There is limited epidemiologic literature focused specifically on this procedure.

METHODS

New York's Statewide Planning and Research Cooperative System database, an all-payer hospitalization reporting system, was queried to identify all patients undergoing primary isolated atlantoaxial fusion in the state from 1997 to 2012. Demographic and clinical data were extracted and analyzed. United States Census Bureau figures were used to calculate population-adjusted surgical rates.

RESULTS

One thousand five hundred fifty-nine patients underwent isolated primary atlantoaxial fusion during the study period. The overall population-adjusted annual surgical rate did not change significantly over time. By 2012, individuals aged ≥70 years had the highest incidence of surgery [2.37 per 100,000 population; 95% confidence interval (95% CI) 1.68-3.07]. Medicare was the most common payer (44.0% of claims). Approximately 85% of patients had a Charlson/Deyo Comorbidity Index of zero or one. Over time, a significantly lower proportion of atlantoaxial fusions were attributable to rheumatic disease, and a significantly higher proportion were due to fracture. By 2012, management of fractures was the most common indication for C1-C2 fusion (44.1% of cases). Dysphagia or dysphonia occurred after 0.8% of cases, dural tear after 0.3%, infection after 0.5%, and seroma, hematoma, or hemorrhage after 0.5%. In-hospital mortality was 2.7%, of which 76% had fracture as the surgical indication.

CONCLUSION

Isolated atlantoaxial fusions have been performed at a stable, low level over the past 16 years in New York. Although most of these patients are relatively healthy pre-operatively, approximately one in 10 experience an in-hospital complication and nearly 3% die in-hospital. Knowledge of these risks will hopefully spur further efforts to minimize them and allow for more accurate counseling of patients and their families.

LEVEL OF EVIDENCE

4.

Reoperation Rates After Surgery for Degenerative Cervical Spine Disease According to Different Surgical Procedures: National Population-based Cohort Study

STUDY DESIGN

National population-based cohort study.

OBJECTIVE

To evaluate reoperation rates of cervical spine surgery for cervical degenerative conditions utilizing a national population database.

SUMMARY OF BACKGROUND DATA

There is an inherently low incidence of reoperation after surgery for cervical degenerative disease. Therefore, it is difficult to sufficiently power studies to detect differences between reoperation rates of different cervical surgical procedures. National population-based databases provide large, longitudinally followed cohorts that may help overcome this challenge.

METHODS

We used the Korean Health Insurance Review and Assessment Service national database to select our study population. We included patients with diagnosis of cervical spondylotic radiculopathy or myelopathy who underwent cervical surgeries from January 2009 to June 2014. We separated patients into three groups based on surgical procedures: discectomy or corpectomy with anterior fusion, laminoplasty, or laminectomy with posterior fusion. Age, sex, presence of diabetes, osteoporosis, associated comorbidities, number of operated cervical disc levels, and hospital types were considered potential confounding factors. Reoperation rates were analyzed over early and late periods.

RESULTS

The reoperation rate over the entire follow-up period was 3.31%. Overall, the reoperation rate was significantly higher after laminectomy with posterior fusion or laminoplasty than after discectomy or corpectomy with anterior fusion. A similar pattern was seen during the late period. In the early period, rates were higher only after laminectomy with posterior fusion than after discectomy or corpectomy with anterior fusion. Sex, presence of diabetes, associated comorbidities, and hospital types were noted to be risk factors for reoperation.

CONCLUSION

The reoperation rate was higher after laminectomy with posterior fusion or laminoplasty. Given clinical scenarios in which either anterior or posterior approaches can be utilized, risk of reoperation can be another variable to consider in surgical planning and patient education.

LEVEL OF EVIDENCE

3.

Predicting Occurrence of Spine Surgery Complications Using "Big Data" Modeling of an Administrative Claims Database

BACKGROUND

Postoperative metrics are increasingly important in determining standards of quality for physicians and hospitals. Although complications following spinal surgery have been described, procedural and patient variables have yet to be incorporated into a predictive model of adverse-event occurrence. We sought to develop a predictive model of complication occurrence after spine surgery.

METHODS

We used longitudinal prospective data from a national claims database and developed a predictive model incorporating complication type and frequency of occurrence following spine surgery procedures. We structured our model to assess the impact of features such as preoperative diagnosis, patient comorbidities, location in the spine, anterior versus posterior approach, whether fusion had been performed, whether instrumentation had been used, number of levels, and use of bone morphogenetic protein (BMP). We assessed a variety of adverse events. Prediction models were built using logistic regression with additive main effects and logistic regression with main effects as well as all 2 and 3-factor interactions. Least absolute shrinkage and selection operator (LASSO) regularization was used to select features. Competing approaches included boosted additive trees and the classification and regression trees (CART) algorithm. The final prediction performance was evaluated by estimating the area under a receiver operating characteristic curve (AUC) as predictions were applied to independent validation data and compared with the Charlson comorbidity score.

RESULTS

The model was developed from 279,135 records of patients with a minimum duration of follow-up of 30 days. Preliminary assessment showed an adverse-event rate of 13.95%, well within norms reported in the literature. We used the first 80% of the records for training (to predict adverse events) and the remaining 20% of the records for validation. There was remarkable similarity among methods, with an AUC of 0.70 for predicting the occurrence of adverse events. The AUC using the Charlson comorbidity score was 0.61. The described model was more accurate than Charlson scoring (p < 0.01).

CONCLUSIONS

We present a modeling effort based on administrative claims data that predicts the occurrence of complications after spine surgery.

CLINICAL RELEVANCE

We believe that the development of a predictive modeling tool illustrating the risk of complication occurrence after spine surgery will aid in patient counseling and improve the accuracy of risk modeling strategies.

Can Dysphagia Following Anterior Cervical Fusions With rhBMP-2 Be Reduced With Local Depomedrol Application?: A Prospective, Randomized, Placebo-Controlled, Double-Blind Trial

STUDY DESIGN

A prospective, randomized, placebo-controlled, double-blind trial.

OBJECTIVE

The aim of this study was to investigate whether the local administration of depomedrol decreases the severity of dysphagia after anterior cervical discectomy and fusion (ACDF) surgery using bone morphogenetic protein (BMP).

SUMMARY OF BACKGROUND DATA

Although recombinant human BMP-2 is effective in promoting arthrodesis, many physicians avoid using it in anterior cervical spine fusions due to concern for increased incidence of dysphagia, significant pre-vertebral swelling, and airway compromise. Pilot studies have shown that the local application of depomedrol may decrease the incidence of postoperative dysphagia. We performed a prospective, randomized trial to evaluate the efficacy of local depomedrol application in reducing the severity of postoperative dysphagia following anterior cervical fusions using low-dose rhBMP-2. We hypothesized that locally administered depomedrol reduces dysphagia following such surgeries.

METHODS

Fifty patients between 18 and 70 years of age, undergoing 1, 2, and 3-level ACDFs, were randomized to 1 of 2 groups: BMP-2 with depomedrol or BMP-2 with saline. Patients were followed for 4 weeks postoperatively by the study administrator. Dysphagia was measured at 5 time intervals (postoperative days 1, 4, 7, 14, and 28) using a 4-point Modified Dysphagia Scoring System. Additional data regarding overall length of hospital stay and the administration of dysphagia-directed treatments were also recorded.

RESULTS

Twenty-seven patients were randomized to the treatment (depomedrol) group and 23 were randomized to the control (saline) group. The 2 groups were nearly identical in terms of their demographic and operative characteristics. Patients receiving depomedrol experienced decreased dysphagia incidence and magnitude at all time intervals, with differences reaching statistical significance on postoperative days 4, 7, 14, and 28 (P < 0.05).

CONCLUSION

This study provides Level 1 evidence that locally administered depomedrol on a collagen sponge significantly decreases postoperative dysphagia incidence and magnitude following anterior cervical spine fusion using low-dose rhBMP-2.

LEVEL OF EVIDENCE

1.

Improved capture of adverse events after spinal surgery procedures with a longitudinal administrative database

OBJECT

The significant medical and economic tolls of spinal disorders, increasing volume of spine surgeries, and focus on quality metrics have made it imperative to understand postoperative complications. This study demonstrates the utility of a longitudinal administrative database for capturing overall and procedure-specific complication rates after various spine surgery procedures.

METHODS

The Thomson Reuters MarketScan Commercial Claims and Encounters and the Medicare Supplemental and Coordination of Benefits database was used to conduct a retrospective analysis of longitudinal administrative data from a sample of approximately 189,000 patients. Overall and procedure-specific complication rates at 5 time points ranging from immediately postoperatively (index) to 30 days postoperatively were computed.

RESULTS

The results indicated that the frequency of individual complication types increased at different rates. The overall complication rate including all spine surgeries was 13.6% at the index time point and increased to 22.8% at 30 days postoperatively. The frequencies of wound dehiscence, infection, and other wound complications exhibited large increases between 10 and 20 days postoperatively, while complication rates for new chronic pain, delirium, and dysrhythmia increased more gradually over the 30-day period studied. When specific surgical procedures were considered, 30-day complication rates ranged from 8.6% in single-level anterior cervical fusions to 27.3% in multilevel combined anterior and posterior lumbar spine fusions.

CONCLUSIONS

This study demonstrates the usefulness of a longitudinal administrative database in assessing postoperative complication rates after spine surgery. Use of this database gave results that were comparable to those in prospective studies and superior to those obtained with nonlongitudinal administrative databases. Longitudinal administrative data may improve the understanding of overall and procedure-specific complication rates after spine surgery.

Three-Dimensional Changes of Maxilla after Secondary Alveolar Cleft Repair: Differences Between rhBMP-2 and Autologous Iliac Crest Bone Grafting

BACKGROUND

Recombinant human bone morphogenetic protein (rhBMP)-2 has been used as an alternative to autologous bone transferring, a standard method of treatment. However, its potential adverse effect on anterior maxillary arch is unknown. Thus, the purpose of this study was to quantify sagittal and transversal changes of anterior maxilla after secondary alveolar cleft repair using traditional iliac crest bone grafting versus rhBMP-2.

METHODS

Twelve unilateral complete cleft lip and palate patients were randomly divided into 2 groups. In group 1, patients underwent traditional iliac crest bone grafting transferring (n = 4), and in group 2, patients underwent alveolar cleft reconstruction using collagen matrix with lyophilized rhBMP-2 (n = 8). Computed tomography (CT) imaging was performed preoperatively and at 1 year postoperatively, using a previously standardized protocol. A three-dimensional (3D) CT cephalometric analysis of the linear and angular measurements of the sagittal and transverse maxilla planes was performed to assess intra- and intergroup maxillary changes.

RESULTS

Intra- and intergroup comparisons of the pre- and postoperative 3D CT cephalometric linear and angular measurements of the sagittal and transverse maxilla planes showed no significant (all P > 0.05) differences among all studied variables.

CONCLUSIONS

There were no significant anterior maxilla changes after maxillary cleft repair either using iliac crest bone grafting or rhBMP-2.