Complications and Risk Factors Using Structural Allograft Versus Synthetic Cage: Analysis 17 783 Anterior Cervical Discectomy and Fusions Using a National Registry

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine the rates of perioperative complications in patients undergoing anterior cervical discectomy and fusion (ACDF) with allograft versus synthetic cage.

METHODS

A large national administrative health care database was queried for ACDF procedures performed between 2007 and 2014 using ICD-9 (International Statistical Classification of Diseases, 9th revision) and CPT (Current Procedural Terminology) codes. Cases that utilized structural allograft and synthetic cages were identified via CPT codes. Gender, age, frequency of obesity, cigarette use, diabetes, and number of levels fused were compared between the 2 cohorts using χ² test. Complications within 90 days were identified via ICD-9 codes and compared between the 2 cohorts. Revision rates within 2 years were noted.

RESULTS

A total of 10 648 ACDF cases using synthetic cages and 7135 ACDFs using structural allograft were identified. The demographics between the 2 cohorts were similar. Overall complication rate was 8.71% in the synthetic cage group compared with 7.76% in the structural allograft group (P < .01). Use of synthetic cage was associated with higher rate of respiratory complications, 0.57% compared with 0.31% in the structural allograft cohort (P = .03), while use of structural allograft was associated with a higher rate of dysphagia, 0.64% compared with 0.33% (P < .01). Revision rate at 2 years was 0.50% and 0.56% in the synthetic cage and allograft groups, respectively (P = .03).

CONCLUSIONS

This data suggests that synthetic cages are associated with a marginally higher overall rate of complications with similar revision rates.

A Multicenter Radiographic Evaluation of the Rates of Preoperative and Postoperative Malalignment in Degenerative Spinal Fusions

STUDY DESIGN

Multicenter, retrospective, institutional-review-board -approved study at 18 institutions in the United States with 24 treating investigators.

OBJECTIVE

This study was designed to retrospectively assess the prevalence of spinopelvic malalignment in patients who underwent one- or two-level lumbar fusions for degenerative (nondeformity) indications and to assess the incidence of malalignment after fusion surgery as well as the rate of alignment preservation and/or correction in this population.

SUMMARY OF BACKGROUND DATA

Spinopelvic malalignment after lumbar fusion has been associated with lower postoperative health-related quality of life and elevated risk of adjacent segment failure. The prevalence of spinopelvic malalignment in short-segment degenerative lumbar fusion procedures from a large sample of patients is heretofore unreported and may lead to an under-appreciation of these factors in surgical planning and ultimate preservation or correction of alignment.

METHODS

Lateral preoperative and postoperative lumbar radiographs were retrospectively acquired from 578 one- or two-level lumbar fusion patients and newly measured for lumbar lordosis (LL), pelvic incidence (PI), and pelvic tilt. Patients were categorized at preop and postop time points as aligned if PI-LL < 10° or malaligned if PI-LL≥10°. Patients were grouped into categories based on their alignment progression from pre- to postoperative, with preserved (aligned to aligned), restored (malaligned to aligned), not corrected (malaligned to malaligned), and worsened (aligned to malaligned) designations.

RESULTS

Preoperatively, 173 (30%) patients exhibited malalignment. Postoperatively, 161 (28%) of patients were malaligned. Alignment was preserved in 63%, restored in 9%, not corrected in 21%, and worsened in 7% of patients.

CONCLUSION

This is the first multicenter study to evaluate the preoperative prevalence and postoperative incidence of spinopelvic malalignment in a large series of short-segment degenerative lumbar fusions, finding over 25% of patients out of alignment at both time points, suggesting that alignment preservation/restoration considerations should be incorporated into the decision-making of even degenerative lumbar spinal fusions.

LEVEL OF EVIDENCE

3.

Allograft Versus Demineralized Bone Matrix in Instrumented and Noninstrumented Lumbar Fusion: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

The aim was to determine the fusion efficacy of allograft and demineralized bone matrix (DBM) in lumbar instrumented and noninstrumented fusion procedures for degenerative lumbar disorders.

METHODS

A literature search was conducted using the PubMed and Cochrane databases. To be considered, publications had to meet 4 criteria: patients were treated for a degenerative lumbar disorder, a minimum group size of 10 patients, use of allograft or DBM, and at least a 2-year follow-up. Data on the study population, follow-up time, surgery type, grafting material, fusion rates, and its definition were collected.

RESULTS

The search yielded 692 citations with 17 studies meeting the criteria including 4 retrospective and 13 prospective studies. Six studies used DBM and 11 employed allograft alone or in the combination with autograft. For the allograft, fusion rates ranged from 58% to 68% for noninstrumented and from 68% to 98% for instrumented procedures. For DBM, fusion rates were 83% for noninstrumented and between 60% and 100% for instrumented lumbar fusion procedures.

CONCLUSIONS

Both allograft and DBM appeared to provide similar fusion rates in instrumented fusions. On the other hand, in noninstrumented procedures DBM was superior. However, a large variation in the type of surgery, outcomes collection, lack of control groups, and follow-up time prevented any significant conclusions. Thus, studies comparing the performance of allograft and DBM to adequate controls in large, well-defined patient populations and with a sufficient follow-up time are needed to establish the efficacy of these materials as adjuncts to fusion.

Postoperative Complications Associated With rhBMP2 Use in Posterior/Posterolateral Lumbar Fusion

STUDY DESIGN

Retrospective database review.

OBJECTIVE

Posterior/posterolateral lumbar fusion (PLF) is an effective treatment for a variety of spinal disorders; however, variations in surgical technique have different complication profiles. The aim of our study was to quantify the frequency of various complications in patients undergoing PLF with and without human recombinant bone morphogenetic protein 2 (rhBMP2).

METHODS

We queried the orthopedic subset of the Medicare database (PearlDiver) between 2005 and 2011 for patients undergoing PLF procedures with and without rhBMP2. Complication and reoperation rates were analyzed within 1 year of the index procedure. Complications assessed include: acute renal failure, deep vein thrombosis, dural tear, hematoma, heterotopic ossification, incision and drainage, cardiac complications, nervous system complications, osteolysis, pneumonia, pseudarthrosis, pulmonary embolism, radiculopathy, respiratory complications, sepsis, urinary retention, urinary tract infection, mechanical, and wound complications. Chi-square analysis was used to calculate the complication differences between the groups.

RESULTS

Our data revealed higher overall complication rates in patients undergoing PLF with rhBMP2 versus no_rhBMP2 (76.9% vs 68.8%, P < .05). Stratified by gender, rhBMP2 males had higher rates of mechanical complications, pseudarthrosis, and reoperations compared with no_rhBMP2 males (P < .05), whereas rhBMP2 females had higher rates of pseudarthrosis, urinary tract infection, and urinary retention compared with no_rhBMP2 females (P < .05).

CONCLUSION

Our data revealed higher overall complication rates in PLF patients given rhBMP2 compared with no_rhBMP2. Furthermore, our data suggests that rhBMP2-associated complications may be gender specific.

Trends Analysis of rhBMP2 Utilization in Single-Level Anterior Lumbar Interbody Fusion in the United States

STUDY DESIGN

Retrospective case study.

OBJECTIVE

To evaluate the trends and demographics of recombinant human bone morphogenetic protein 2 (rhBMP2) utilization in single-level anterior lumbar interbody fusion (ALIF) in the United States.

METHODS

Patients who underwent single-level ALIF from 2005 to 2011 were identified by searching ICD-9 diagnosis and procedure codes in the PearlDiver Patient Records Database (PearlDiver Technologies, Fort Wayne, IN), a national database of orthopedic insurance records. The year of procedure, age, gender, and region of the United States were analyzed for each patient.

RESULTS

A total of 921 patients were identified who underwent a single-level ALIF in this study. The average rate of single-level ALIF with rhBMP2 utilization increased (35%-48%) from 2005 to 2009, but sharply decreased to 16.7% in 2010 and 15.0% in 2011. The overall incidence of single-level ALIF without rhBMP2 (0.20 cases per 100 000 patients) was more than twice of the incidence of single-level ALIF with rhBMP2 (0.09 cases per 100 000 patients). The average rate of single-level ALIF with rhBMP2 utilization is highest in West (41.4%), followed by Midwest (33.3%), South (26.5%) and Northeast (22.2%). The highest incidence of single-level ALIF with rhBMP2 was observed in the group aged less than 65 years (compared with any other age groups, P < .001), with an incidence of 0.21 per 100 000 patients.

CONCLUSIONS

The incidence of rhBMP2 utilization in single-level ALIF increased from 2006 to 2009, but decreased in 2010 and 2011. The Northeast region had the lowest incidence of rhBMP2 utilization. The group aged less than 65 years trended to have the higher incidence of single-level ALIF with rhBMP2 utilization.

Trends and Costs of Anterior Cervical Discectomy and Fusion: a Comparison of Inpatient And Outpatient Procedures

STUDY DESIGN

Epidemiologic Study.

OBJECTIVES

To identify the trends in utilization of outpatient discharge for single level anterior cervical discectomy and fusion (ACDF), between 2007 and 2014, and to compare the costs and incidence of complications against a cohort of inpatients.

METHODS

We retrospectively reviewed 18,386 patients from the PearlDiver database from between 2007 and 2014. Discharge status was determined from billing codes. The total cost of all procedures and diagnostic tests, was determined for the global period from the time of diagnosis up until 90-days post-operatively, and the incidence of complications was recorded for 30-days.

RESULTS

The proportion of outpatient discharges was stable around 20% from 2007 to 2014 (range17-23%). The mean 90-day cost was lower for outpatients ($39,528 v. $47,330) but reimbursement fell nearly 1/3 from 2007-2014 for both groups, and the difference between the two narrowed over time ($13,745 difference in 2008, to $3,834 in 2014). Outpatients had a lower incidence of overall 30-day complications (9.5% v. 18.6%, p<0.0001), but were also significantly less comorbid (mean Charlson comorbidity index 2.32 v. 3.85, p<0.001). Older patient age, obesity, cardiac, renal, and pulmonary comorbidity were each more common in the inpatients (p<0.05 for each).

CONCLUSIONS

Outpatient discharge after ACDF is a viable treatment option with a reasonable safety profile and decreased costs relative to inpatient admission. Appropriate patient selection is key, and the standard of care nationally for the comorbid patient remains inpatient admission. The economic trends and epidemiologic data presented here should be useful for health policy decisions.

Complication Rates in Posterior Lumbar Interbody Fusion (PLIF) Surgery With Human Bone Morphogenetic Protein 2: Medicare Population

STUDY DESIGN

Retrospective cohort study among Medicare beneficiaries who underwent posterior lumbar interbody fusion (PLIF) surgery.

OBJECTIVE

To identify the complication rates associated with the use of bone morphogenetic protein 2 (BMP2) in PLIF. Human BMP2 is commonly used in the "off-label" manner for various types of spine fusion procedures, including PLIF. However, recent studies have reported potential complications associated with the recombinant human BMP2 (rhBMP2) use in the posterior approach.

METHODS

Medicare records within the PearlDiver database were queried for patients undergoing PLIF procedure with and without rhBMP2 between 2005 and 2010. We evaluated complications within 1 year postoperatively. Chi-square was used to compare the complication rates between the 2 groups.

RESULTS

A total of 8609 patients underwent PLIF procedure with or without rhBMP2. Individual complication rates in the rhBMP2 group ranged from 0.45% to 7.68% compared with 0.65% to 10.99 in the non-rhBMP2 group. Complication rates for cardiac, pulmonary, lumbosacral neuritis, infection, wound, and urinary tract (include acute kidney failure and post-operative complications) were significantly lower in the rhBMP2 group (P < .05). There was no difference in the rates of central nervous system complications or radiculitis between the 2 groups.

CONCLUSION

Our data showed that the patients who received rhBMP2 had lower complication rates compared to the non-rhBMP2 group. However, use of rhBMP2 was associated with a higher rate of pseudarthrosis. We did not observe any difference in radiculitis and central nervous system complications between the groups.

Trends, Costs, and Complications of Anterior Cervical Discectomy and Fusion With and Without Bone Morphogenetic Protein in the United States Medicare Population

STUDY DESIGN

Retrospective database review.

OBJECTIVES

After the Food and Drug Administration approved bone morphogenetic protein-2 (BMP) in 2002, BMP was used off-label in the cervical spine to increase bone growth and bony fusion. Since then, concerns have been raised regarding complication rates and safety. This study was conducted to examine the use of BMP in anterior cervical discectomy and fusion (ACDF) in the Medicare population and to determine risk of complications and associated costs within 90 days of surgery.

METHODS

Patients who underwent ACDF were identified using Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision Procedure codes (ICD9-P). Complications were identified using ICD9 diagnostic codes. Charges were calculated as amount billed, and reimbursements were calculated as amounts paid by Medicare. Data for these analyses came from a nationwide claims database.

RESULTS

A total of 215 047 patients were identified who had ACDF from 2005 to 2011. For the majority of the procedures (89.0%), BMP was not used. BMP use rose from 11.84% in 2005 to a peak of 16.73% in 2007 before decreasing to 12.01% in 2011. BMP was used 16% more in women than men. BMP use was the highest in the West (13.6%) followed by Midwest (11.8%), South (10.6%), and Northeast (7.5%). There was a higher overall complication rate in the BMP group (2.1%) compared with the non-BMP group (1.9%) (odds ratio [OR] = 1.11, 95% CI = 1.01-1.22). The BMP group also had a higher rate of wound complications (0.98% vs 0.76%, OR = 1.29, 95% CI = 1.12-1.48). In this study population, there was no difference in dysphagia/hoarseness, neurologic, medical, or other complications. During the 90-day perioperative period, BMP surgeries were charged at 17.6% higher than non-BMP surgeries.

CONCLUSIONS

The use of BMP in ACDF in the Medicare population has decreased since a peak in 2007. The rate of wound and overall complications for BMP use with ACDF was higher than without. Our results regarding dysphagia/hoarseness did not show a statistically meaningful difference, which is in contrast with many other studies. Charges associated with BMP use were higher during the 90-day perioperative period.

Trends Analysis of rhBMP Utilization in Single-Level Posterior Lumbar Interbody Fusion in the United States

STUDY DESIGN

Retrospective study.

OBJECTIVES

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been widely used in spinal fusion surgery, but there is little information on rhBMP-2 utilization in single-level posterior lumbar interbody fusion (PLIF). The purpose of our study was to evaluate the trends and demographics of rhBMP-2 utilization in single-level PLIF.

METHODS

Patients who underwent single-level PLIF from 2005 to 2011 were identified by searching ICD-9 diagnosis and procedure codes in the PearlDiver Patient Records Database, a national database of orthopedic insurance records. The year of procedure, age, gender, and region of the United States were recorded for each patient. Results were reported for each variable as the incidence of procedures identified per 100 000 patients searched in the database.

RESULTS

A total of 2735 patients had single-level PLIF. The average rate of single-level PLIF with rhBMP-2 maintained at a relatively stable level (28% to 31%) from 2005 to 2009, but decreased in 2010 (9.9%) and 2011 (11.8%). The overall incidence of single-level PLIF without rhBMP-2 (0.68 cases per 100 000 patients) was statistically higher (P < .01) compared to single-level PLIF with rhBMP-2 (0.21 cases per 100 000 patients). The average rate of single-level PLIF with rhBMP-2 utilization was the highest in West (30.1%), followed by Midwest (26.9%), South (20.5%), and Northeast (17.8%). The highest incidence of single-level PLIF with rhBMP-2 was observed in the age group <65 years (0.3 per 100 000 patients).

CONCLUSIONS

To our knowledge, this is the first study to report on the demographics associated with rhBMP-2 use in single-level PLIF. There was a 3-fold increase in the rate of PLIF without rhBMP-2 compared to PLIF with rhBMP-2, with both procedures being mainly done in patients less than 65 years of age.

ACDF Graft Selection by Surgeons: Survey of AOSpine Members

STUDY DESIGN

Cross-sectional survey study.

OBJECTIVE

To determine what are the most commonly used graft materials in anterior cervical discectomy and fusion and whether the choice of graft is affected by surgeon's training, years in practice, geographic location, practice setting, or surgeon's perceived difficulty in achieving fusion.

METHODS

A 23-question survey was sent out to 5334 surgeons using the Global AO Spine database. Response data was then stratified into surgeon training, years of practice, practice type, and global region.

RESULTS

Overall, surgeons believe that graft selection affects fusion rates (89.3% of surgeons) and affects time to fusion (86.0% of surgeons). The use of a cage is currently the most common structural graft component used worldwide at 64.1%. Of surgeons that use cages, the PEEK Cage makes up 84%. North American surgeons differ from this global trend and use composite allograft more commonly. The choice to add a nonstructural graft component was reported at 74%. This result was similar for performing multilevel fusions at 72.8%. The selection of nonstructural graft material depends on whether the type of surgery is considered simple or complex. Most surgeons are not satisfied with available literature comparing effectiveness of grafts but believed that there was sufficient evidence to support the use of their chosen graft.

CONCLUSION

Almost all surgeons believe that fusion is important to anterior cervical discectomy and fusion surgery outcomes and that most surgeons believe graft choice affects fusion. However, this survey indicates that there is great variability in the type of graft material used by spine surgeons across the world.

Trends and Cost of Posterior Cervical Fusions With and Without Recombinant Human Bone Morphogenetic Protein-2 in the US Medicare Population

STUDY DESIGN

Retrospective database review.

OBJECTIVE

To analyze and report the trends and cost of posterior cervical fusions (PCFs) with and without off-label recombinant human bone morphogenetic protein-2 (rhBMP-2) in the Medicare population.

METHODS

Patient records from the PearlDiver database were retrospectively reviewed from January 1, 2005, to December 31, 2012, to distinguish individuals who underwent a PCF with or without rhBMP-2. Total numbers, incidence, age, gender, geographic region, reimbursement, and length of stay were analyzed and summarized.

RESULTS

The combined total of non-rhBMP-2 (n = 39 479; 85.51%) and rhBMP-2 PCF (n = 6692; 14.49%) procedures performed between 2005 and 2012 was 46 171. In general, the number of PCFs without rhBMP-2 consistently increased over time, while the number of PCFs with rhBMP-2 had only a slight increase from 2005 to 2012. On average, PCFs without rhBMP-2 were associated with $1197 higher cost than those with rhBMP-2, but the average length of stay was similar (6 days). From 2005 to 2012, the average cost for procedures with and without rhBMP-2 increased by $12 605 and $7291, respectively. The percentage of rhBMP-2 use peaked in 2007 and dwindled until 2010, and declined an additional 2.84% from 2011 to 2012. Multiple age, region, and gender tendencies were observed.

CONCLUSIONS

To our knowledge, this was the first study to use the PearlDiver database to report incidence and cost trends of PCF procedures. This article provides meaningful trend data on PCFs to surgeons and clinicians, researchers, and patients, as well as functions as a beacon for future research questions.

A Retrospective Analysis of Complications Associated With Bone Morphogenetic Protein 2 in Anterior Lumbar Interbody Fusion

STUDY DESIGN

Retrospective review.

OBJECTIVE

The aim of our study was to quantify the frequency of complications associated with recombinant human bone morphogenetic protein 2 (rhBMP-2) use in anterior lumbar interbody fusion (ALIF).

METHODS

The orthopedic subset of the Medicare database (PearlDiver) was queried for this retrospective cohort study using International Statistical Classification of Diseases 9 (ICD-9) and Current Procedure Terminology (CPT) codes for ALIF procedures with and without rhBMP-2 between 2005 and 2010. Frequencies of complications and reoperations were then identified within 1 year from the index procedure. Complications included reoperations, pulmonary embolus, deep vein thrombosis, myocardial infarction, nerve-related complications, incision and drainage procedures, wound, sepsis, pneumonia, urinary tract infections, respiratory, heterotopic ossification, retrograde ejaculation, radiculopathy, and other medical complications. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the statistical significance.

RESULTS

We identified a total of 41 865 patients who had an ALIF procedure. A total of 14 384 patients received rhBMP-2 while 27 481 did not. Overall, 6016 (41.8%) complications within 1 year from surgery were noted within the group who received rhBMP-2 and 12 950 (47.1%) complications within 1 year from surgery were recorded in those who did not receive rhBMP-2 (OR = 0.81, CI = 0.77-0.84). Overall, exposure to rhBMP-2 was associated with significantly decreased odds of complications with exception to reoperation rates (0.9% rhBMP-2 vs 1.0% no rhBMP-2; OR = 0.88, CI = 0.71-1.09) and radiculopathy (4.4% rhBMP-2 vs 4.3% no rhBMP-2; OR = 1.02, CI = 0.93-1.13).

CONCLUSIONS

The use of rhBMP-2 in patients undergoing ALIF procedure was associated with a significantly decreased rate of complications. Further studies are needed to elucidate a true incidence of complication.

Autograft versus Allograft for Cervical Spinal Fusion: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To compare the effectiveness and safety between iliac crest bone graft (ICBG), non-ICBG autologous bone, and allograft in cervical spine fusion. To avoid problems at the donor site, various allograft materials have been used as a substitute for autograft. However, there are still questions as to the comparative effectiveness and safety of cadaver allograft compared with autologous ICBG.

METHODS

A systematic search of multiple major medical reference databases was conducted to identify studies evaluating spinal fusion in patients with cervical degenerative disk disease using ICBG compared with non-ICBG autograft or allograft or non-ICBG autograft compared with allograft in the cervical spine. Radiographic fusion, patient-reported outcomes, and functional outcomes were the primary outcomes of interest. Adverse events were evaluated for safety.

RESULTS

The search identified 13 comparative studies that met our inclusion criteria: 2 prospective cohort studies and 11 retrospective cohort studies. Twelve cohort studies compared allograft with ICBG autograft during anterior cervical fusion and demonstrated with a low evidence level of support that there are no differences in fusion percentages, pain scores, or functional results. There was insufficient evidence comparing patients receiving allograft with non-ICBG autograft for fusion, pain, revision, and functional and safety outcomes. No publications directly comparing non-ICBG autograft with ICBG were found.

CONCLUSION

Although the available literature suggests ICBG and allograft may have similar effectiveness in terms of fusion rates, pain scores, and functional outcomes following anterior cervical fusion, there are too many limitations in the available literature to draw any significant conclusions. No individual study provided greater than class III evidence, and when evaluating the overall body of literature, no conclusion had better than low evidence support. A prospective randomized trial with adequate sample size to compare fusion rates, efficacy measures, costs, and safety is warranted.

Analysis of Recombinant Human Bone Morphogenetic Protein-2 Use in the Treatment of Lumbar Degenerative Spondylolisthesis

Study Design Retrospective database review. Objective To identify trends of the recombinant human bone morphogenetic protein-2 (rhBMP-2) use in the treatment of lumbar degenerative spondylolisthesis (LDS). Methods PearlDiver Patient Record Database was used to identify patients who underwent lumbar fusion for LDS between 2005 and 2011. The distribution of bone morphogenetic protein use rate (BR) in various surgical procedures was recorded. Patient numbers, reoperation numbers, BR, and per year BR (PYBR) were stratified by geographic region, gender, and age. Results There were 11,335 fusion surgeries, with 3,461 cases using rhBMP-2. Even though PYRB increased between 2005 and 2008, there was a significant decrease in 2010 for each procedure: 404 (34.5%) for posterior interbody fusion, 1,282 (34.3%) for posterolateral plus posterior interbody fusion (PLPIF), 1,477 (29.2%) for posterolateral fusion, and 335 (22.4%) for anterior lumbar interbody fusion. In patients using rhBMP-2, the reoperation rate was significantly lower than in patients not using rhBMP-2 (0.69% versus 1.07%, p < 0.0001). Male patients had higher PYBR compared with female patients in 2008 and 2009 (p < 0.05). The West region and PLPIF had the highest BR and PYBR. Conclusions Our data shows that the revision rates were significantly lower in patients treated with rhBMP-2 compared with patients not treated with rhBMP-2. Furthermore, rhBMP-2 use in LDS varied by year, region, gender, and type of fusion technique. In the West region, the posterior approach and patients 65 to 69 years of age had the highest rate of rhBMP-2 use.

Iliac Crest Bone Graft versus Local Autograft or Allograft for Lumbar Spinal Fusion: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To compare the effectiveness and safety between iliac crest bone graft (ICBG) and local autologous bone and allograft in the lumbar spine.

METHODS

A systematic search of multiple major medical reference databases identified studies evaluating spinal fusion in patients with degenerative joint disease using ICBG, local autograft, or allograft in the thoracolumbar spine.

RESULTS

Six comparative studies met our inclusion criteria. A "low" strength of the overall body of evidence suggested no difference in fusion percentages in the lumbar spine between local autograft and ICBG. We found no difference in fusion percentages based on low evidence comparing allograft with ICBG autograft. There were no differences in pain or functional results comparing local autograft or allograft with ICBG autograft. Donor site pain and hematoma/seroma occurred more frequently in ICBG autograft group for lumbar fusion procedures. There was low evidence around the estimate of patients with donor site pain following ICBG harvesting, ranging from 16.7 to 20%. With respect to revision, low evidence demonstrated no difference between allograft and ICBG autograft. There was no evidence comparing patients receiving allograft with local autograft for fusion, pain, functional, and safety outcomes.

CONCLUSION

In the lumbar spine, ICBG, local autograft, and allograft have similar effectiveness in terms of fusion rates, pain scores, and functional outcomes. However, ICBG is associated with an increased risk for donor site-related complications. Significant limitations exist in the available literature when comparing ICBG, local autograft, and allograft for lumbar fusion, and thus ICBG versus other fusion methods necessitates further investigation.

Trends of Posterior Long Segment Fusion with and without Recombinant Human Bone Morphogenetic Protein 2 in Patients with Scoliosis

STUDY DESIGN

Retrospective study.

OBJECTIVE

Symptomatic scoliosis can be a source of severe pain and disability. When nonoperative treatments fail, spine fusion is considered as an effective procedure in scoliosis management. The purpose of this study was to evaluate the trends of patients with scoliosis undergoing posterior long segment fusion (PLSF) with and without recombinant human bone morphogenetic protein 2 (rhBMP-2).

METHODS

Patients within the orthopedic subset of Medicare database undergoing PLSF from 2005 to 2011 were identified using the PearlDiver Patient Records Database. Both diagnosis and procedural International Classification of Diseases, ninth edition and Current Procedural Terminology codes were used. The year of procedure, age, sex, region, and rhBMP-2 use were recorded.

RESULTS

In total, 1,265,591 patients with scoliosis were identified with 29,787 PLSF surgeries between 2005 and 2011. The incidence of PLSF procedures increased gradually from 2005 to 2009, decreased in 2010 (p < 0 0.01), and grew again in 2011. Patients over age 84 years had the highest incidence of PLSF. The lowest incidence of the procedures was in the Northeast, 5.96 per 100,000 patients. Sex differences were observed with a male-to-female ratio of 0.40 (p < 0.01). The use of rhBMP-2 for PLSF increased steadily from 2005 to 2009; the numbers dropped dramatically in 2010 and returned by 2011.

CONCLUSIONS

According to our study, patients with scoliosis demonstrated a 0.6575 average incidence increase of PLSF treatments annually. There were significant differences in incidence of PLSF procedure and patient demographics. Additionally, rhBMP-2 consumption significantly changed when we stratified it by sex, age, and region respectively.

Clinical and Radiographic Results of Indirect Decompression and Posterior Cervical Fusion for Single-Level Cervical Radiculopathy Using an Expandable Implant with 2-Year Follow-Up

Background Indirect posterior cervical nerve root decompression and fusion performed by placing bilateral posterior cervical cages in the facet joints from a posterior approach has been proposed as an option to treat select patients with cervical radiculopathy. The purpose of this study was to report 2-year clinical and radiologic results of this treatment method. Methods Patients who failed nonsurgical management for single-level cervical radiculopathy were recruited. Surgical treatment involved a posterior approach with decortication of the lateral mass and facet joint at the treated level followed by placement of the DTRAX Expandable Cage (Providence Medical Technology, Lafayette, California, United States) into both facet joints. Iliac crest bone autograft was mixed with demineralized bone matrix and used in all cases. The Neck Disability Index (NDI), visual analog scale (VAS) for neck and arm pain, and SF-12 v.2 questionnaire were evaluated preoperatively and 2 years postoperatively. Segmental (treated level) and overall C2-C7 cervical lordosis, disk height, adjacent segment degeneration, and fusion were assessed on computed tomography scans and radiographs acquired preoperatively and 2 years postoperatively. Results Overall, 53 of 60 enrolled patients were available at 2-year follow-up. There were 35 females and 18 males with a mean age of 53 years (range: 40-75 years). The operated level was C3-C4 (N = 3), C4-C5 (N = 6), C5-C6 (N = 36), and C6-C7 (N = 8). The mean preoperative and 2-year scores were NDI: 32.3 versus 9.1 (p < 0.0001); VAS Neck Pain: 7.4 versus 2.6 (p < 0.0001); VAS Arm Pain: 7.4 versus 2.6 (p < 0.0001); SF-12 Physical Component Summary: 34.6 versus 43.6 (p < 0.0001), and SF-12 Mental Component Summary: 40.8 versus 51.4 (p < 0.0001). No significant changes in overall or segmental lordosis were noted after surgery. Radiographic fusion rate was 98.1%. There was no device failure, implant lucency, or surgical reinterventions. Conclusions Indirect decompression and posterior cervical fusion using an expandable intervertebral cage may be an effective tissue-sparing option in select patients with single-level cervical radiculopathy.

Synthetic bone graft versus autograft or allograft for spinal fusion: a systematic review

The purpose of this review was to compare the efficacy and safety of synthetic bone graft substitutes versus autograft or allograft for the treatment of lumbar and cervical spinal degenerative diseases. Multiple major medical reference databases were searched for studies that evaluated spinal fusion using synthetic bone graft substitutes (either alone or with an autograft or allograft) compared with autograft and allograft. Randomized controlled trials (RCT) and cohort studies with more than 10 patients were included. Radiographic fusion, patient-reported outcomes, and functional outcomes were the primary outcomes of interest. The search yielded 214 citations with 27 studies that met the inclusion criteria. For the patients with lumbar spinal degenerative disease, data from 19 comparative studies were included: 3 RCTs, 12 prospective, and 4 retrospective studies. Hydroxyapatite (HA), HA+collagen, β-tricalcium phosphate (β-TCP), calcium sulfate, or polymethylmethacrylate (PMMA) were used. Overall, there were no differences between the treatment groups in terms of fusion, functional outcomes, or complications, except in 1 study that found higher rates of HA graft absorption. For the patients with cervical degenerative conditions, data from 8 comparative studies were included: 4 RCTs and 4 cohort studies (1 prospective and 3 retrospective studies). Synthetic grafts included HA, β-TCP/HA, PMMA, and biocompatible osteoconductive polymer (BOP). The PMMA and BOP grafts led to lower fusion rates, and PMMA, HA, and BOP had greater risks of graft fragmentation, settling, and instrumentation problems compared with iliac crest bone graft. The overall quality of evidence evaluating the potential use and superiority of the synthetic biological materials for lumbar and cervical fusion in this systematic review was low or insufficient, largely due to the high potential for bias and small sample sizes. Thus, definitive conclusions or recommendations regarding the use of these synthetic materials should be made cautiously and within the context of the limitations of the evidence.

Sterile Seroma Resulting from Multilevel XLIF Procedure as Possible Adverse Effect of Prophylactic Vancomycin Powder: A Case Report

Study Design Case report.

Objective The objective of this study was to present the unusual case of a 59-year-old woman with a reoccurring sterile postoperative seroma.

Methods A patient was observed postoperatively for any complications or adverse side effects resulting from an initial multilevel anterior/posterior lumbar fusion surgery where 2 g (1 g combined with the bone graft used for posterolateral fusion and 1 g placed in the soft tissues) of prophylactic vancomycin powder was placed within the soft tissues posteriorly before wound closure. The patient's progress was monitored through 6 months following the initial procedure. Six weeks postoperatively, the patient sustained a fall and had increased pain. Magnetic resonance imaging, computed tomography, and X-rays demonstrated a displaced sacral fracture, a large epidural fluid collection, and severe compression of the thecal sac at the lumbar operative sites (L3–5).

Results On the basis of the aforementioned imaging studies and the patient's progressive neurologic deficit, it was apparent at the 6-week follow-up that emergent surgical intervention was necessary. Drainage and examination of an epidural fluid collection along with treatment of a displaced sacral fracture (S1–S2) were performed. The patient had an uneventful postoperative course with resolution of her back pain and neurologic deficit; however, recurrence of the epidural fluid collection requiring serial aspirations confounded the patients' clinical presentation.

Conclusions With the recurrent nature of the seroma being unusual, the cause of the fluid collection and formation is undetermined. With lack of bone morphogenetic protein usage, and few confounding variables accountable, an acute allergic response to topical vancomycin powder is a possible etiology. Analysis with larger patient populations comparing postoperative adverse effects of prophylactic vancomycin powder is recommended.

Neurologic deficit following percutaneous vertebral stabilization

STUDY DESIGN

A retrospective review.

OBJECTIVE

The purpose of this study is to document a series of cases of neurologic deficit following percutaneous vertebral stabilization, to identify patterns of neurologic injury, and to describe potential methods for avoiding these injuries.

SUMMARY OF BACKGROUND DATA

Percutaneous vertebral stabilization procedures, including vertebroplasty and kyphoplasty, have become a widely used for the treatment of osteoporotic vertebral compression fractures, primary and metastatic vertebral tumors, and traumatic burst fractures. Despite an increasing array of indications, there have been few reports of adverse events. Neurologic complications associated with vertebroplasty and kyphoplasty have been described previously as case reports and have generally been considered as infrequent and minor in severity.

METHODS

The clinical course of 14 patients with documented loss of neurologic function following percutaneous vertebral cement augmentation was retrospectively reviewed.

RESULTS

The average patient age was 74.9 years (range, 46-88 years) with 3 male and 11 female patients. Four patients underwent a vertebroplasty procedure while 10 were treated with kyphoplasty. Six patients developed neurologic deficits acutely (<24 hours of procedure). The remaining 8 patients developed neurologic symptoms at an average of 37.1 days (range, 3-112 days) postprocedure. Neurologic deficits were recorded as ASIA A in 4 patients, ASIA B in 2 patients, ASIA C in 1 patient, and ASIA D in 7 patients. Twelve of 14 patients (85.7%) required revision open surgical intervention for treatment of their neurologic injury.

CONCLUSION

Percutaneous vertebroplasty and kyphoplasty have been reported to be safe options for the treatment of painful osteoporotic vertebral fractures. Although complications are infrequent, there remains the potential for catastrophic neurologic injury. Physicians performing these procedures need to be aware of these potential complications and be prepared to respond in an emergent manner (surgically) if a need arises.

Internet-based reference case managers for clinical practice and research collaboration

Historically in medicine, the internet has been used for unidirectional information extraction via search engines that provide database and literature output. Current Web-based case managers allow submission and reception of digital media and have been used to link specialists and provide forums for rapid, bidirectional information sharing.

Epidural injections for the treatment of symptomatic lumbar herniated discs

Epidural steroid injections are widely used as part of the conservative care for symptomatic herniated lumbar discs. There are studies showing their effectiveness, and some studies demonstrating no clinical benefits. The purpose of this study was to evaluate the effectiveness of epidural steroid injections for patients with symptomatic lumbar disc herniations who were surgical candidates. Sixty-nine patients were diagnosed with a herniated disc in the lumbar spine and remained symptomatic despite conservative care, and were treated with an epidural injection in an attempt to avoid surgical discectomy. Of the total group of 69 patients (average age = 44.8 years, range 19-77 years, average follow-up = 1.5 years), 53 (77%) had successful resolution or significant decrease of their symptoms and were able to avoid surgery. Only 16 (23%) patients failed to have significant relief of their symptoms and required surgical treatment of their herniated disc. Epidural steroid injections have a reasonable success rate for the alleviation of radicular symptoms from lumbar herniated discs for up to twelve to twenty-seven months. Patients treated with injections may be able to avoid surgical treatment up to this period and perhaps even longer.

[Bond strength to dentin of resin composites associated with filled and unfilled adhesive systems]

This study analyzed in vitro two brands of one-step adhesive systems of fourth generation (Optisolo--Kerr, filled; and Single Bond--3M, unfilled) and two composite resins (Prodigy--Kerr and Z100--3M), aiming at evaluating their bond strength to dentin. Eighty human extracted molars were embedded in acrylic resin and grounded until dentin was exposed in longitudinal direction. The specimens were divided in 4 groups. Composite resin cones were bonded to the specimens using the mentioned adhesive systems, following the instructions of the manufacturers. The test-specimens were submitted to tensile tests using a 4442 Universal Mini-Instron Machine with the speed of 0.5 mm/min. The results were converted into MPa, according to the area of adhesion, and submitted to statistical analysis with ANOVA. There was significant statistical difference (p < 0.01) between the adhesive systems (F = 7.24). Optisolo (m = 11.03 +/- 4.23) showed better bond strength than Single Bond (m = 8.37 +/- 4.54). There was no significant statistical difference (p > 0.05) between the composites (F = 0.43).

Characteristics of pedicle screw loading. Effect of sagittal insertion angle on intrapedicular bending moments

STUDY DESIGN

A bending analysis of pedicle screws inserted into vertebral body analogues. Intravertebral and intrapedicular pedicle screw bending moments were studied as a function of sagittal insertion angle.

OBJECTIVES

To determine how the pedicle screw bending moment is affected by changes in the insertion angle.

SUMMARY OF BACKGROUND DATA

There is a significant incidence of failure when pedicle screws are used to instrument unstable spinal segments. Extrinsic factors that affect screw bending failure have been poorly characterized. Previous work has demonstrated that intrapedicular pedicle screw bending moments are significantly affected by the sagittal location and depth of pedicle screw placement.

METHODS

Pedicle screw transducers were inserted in analogue vertebrae at one of three orientations: 7 degrees cephalad (toward the superior endplate), 7 degrees caudal (toward the inferior endplate), or parallel to the superior endplate (control). An axial load was applied to the superior endplate of the vertebra, and screw bending moments were recorded directly from the transducers.

RESULTS

Screws angled 7 degrees cephalad developed significantly greater mean intrapedicular bending moments compared with screws inserted caudal or control screws. There was no significant difference in bending moments realized within the vertebral body for the three screw positions.

CONCLUSIONS

Angulating pedicle screws toward the superior endplate increased bending moments within the pedicle. If attention to optimal screw insertion technique can reduce bending moments and potential for screw failure without increasing morbidity, surgical risk, or operative time, then proper insertion technique takes on new importance.

Influence of inhaled nitric oxide and hyperoxia on Na,K-ATPase expression and lung edema in newborn piglets

This study was undertaken to examine the combined effect of nitric oxide (NO) and hyperoxia on lung edema and Na,K-ATPase expression. Newborn piglets were exposed to room air (FiO2 = 0.21), room air plus 50 ppm NO, hyperoxia (FiO2 >/= 0.96) or to hyperoxia plus 50 ppm NO for 4-5 days. Animals exposed to NO in room air experienced only a slight decrease in Na,K-ATPase alpha subunit protein level. Hyperoxia, in the absence of NO, induced both the mRNA and the protein level of Na,K-ATP-ase alpha subunit and significantly increased wet lung weight, extravascular lung water, and alveolar permeability. NO in hyperoxia decreased the hyperoxic-mediated induction of Na,K-ATPase alpha subunit mRNA and protein while wet lung weight, extravascular lung water, and alveolar permeability remained elevated. These results suggest that 50 ppm of inhaled NO may not improve hyperoxic-induced lung injury and may interfere with the expression of Na,K-ATPase which constitutes a part of the cellular defense mechanism against oxygen toxicity.

Mitochondrial, but not peroxisomal, beta-oxidation of fatty acids is conserved in coenzyme A-deficient rat liver

Hepatic coenzyme A (CoA) plays an important role in cellular lipid metabolism. Because mitochondria and peroxisomes represent the two major subcellular sites of lipid metabolism, the present study was designed to investigate the specific impact of hepatic CoA deficiency on peroxisomal as well as mitochondrial beta-oxidation of fatty acids. CoA deficiency (47% decrease in free CoA and 23% decrease in total CoA) was produced by maintaining weanling male Sprague-Dawley rats on a semipurified diet deficient in pantothenic acid (the precursor of CoA) for 5 weeks. Hepatic mitochondrial fatty acid oxidation of short-chain and long-chain fatty acids were not significantly different between control and CoA-deficient rats. Conversely, peroxisomal beta-oxidation was significantly diminished (38% inhibition) in livers of CoA-deficient rats compared to control animals. Peroxisomal beta-oxidation was restored to normal levels when hepatic CoA was replenished. It is postulated that since the role of hepatic mitochondrial beta-oxidation is energy production while peroxisomal beta-oxidation acts mainly as a detoxification system, the mitochondrial pathway of beta-oxidation is spared at the expense of the peroxisomal pathway when liver CoA plummets. The present study may offer an animal model to investigate mechanisms involved in peroxisomal diseases.

Arthroscopic Bankart suture repair for recurrent traumatic unidirectional anterior shoulder dislocations

We report our experience with arthroscopic repair of the Bankart lesion following traumatic unidirectional anterior shoulder dislocation. Thirty consecutive patients (7 women, 23 men; average age, 26.5 years) were followed for an average of 38 months (minimum 2-year follow-up) after arthroscopic Bankart suture repair for recurrent shoulder dislocation. The study included patients who had pure shoulder dislocations (excluding those with instability secondary to subluxation, multidirectional instability, or an atraumatic origin), had experienced an initial frank shoulder dislocation (documented radiographically or requiring the assistance of medical personnel for reduction), and had a Bankart lesion, visualized arthroscopically. Clinical evaluation using the Rowe functional grading system showed 11 patients rated as excellent, 8 as good, 3 as fair, and 8 as poor. Six of 8 patients were rated as poor because they frankly redislocated following their arthroscopic shoulder stabilization. Our study shows a 27% failure rate in this group. Critical reevaluation of the transglenoid arthroscopic Bankart procedure is mandatory to identify the appropriate patient population for this procedure.

Seizure-induced lumbar burst fracture

STUDY DESIGN

This case report illustrates how muscle forces generated during generalized seizure activity can result in severe musculoskeletal trauma. A case is presented of a 35-year-old man who suffered seizure-induced contiguous L1 and L2 lumbar burst fractures.

SUMMARY OF BACKGROUND DATA

To the authors' knowledge, there have been no reports of seizure-associated lumbar burst fractures.

OBJECTIVE

The case is presented to demonstrate how seizure activity can lead to lumbar burst fractures.

METHODS

A 35-year-old man suffered a witnessed tonic-clonic seizure while lying on a couch. He had no other trauma and no history of previous seizure activity. As his mental status cleared in the post-ictal period, he complained of mild low back pain. Upon ambulation, he continued to complain of persistent low back pain. Plain radiographs obtained on hospital visit day 5 identified the L1 and L2 contiguous burst fractures. Initial treatment using a Risser cast was unsuccessful, and the patient subsequently underwent posterior spine fusion with Cotrel-Dubousset segmental instrumentation and an iliac crest bone graft.

RESULTS

At 1-year follow-up, the patient's spine was stable with no evidence of pseudoarthrosis or further kyphosis. He was maintained on anti-seizure medication.

CONCLUSIONS

Forces generated during a tonic-clonic seizure can result in axial skeletal trauma, including thoracic and lumbar burst fractures. Clinical signs of unstable fractures may be subtle. A high index of clinical suspicion is warranted for patients who experience tonic-clonic seizures and who have associated risk factors.

Disruption of mitochondrial energetics and DNA synthesis by the anti-AIDS drug dideoxyinosine

The purpose of this study was to clarify the role of the mitochondria as a site for the reported hepatotoxic effects of the anti-AIDS drug dideoxyinosine (ddI). Data show that ddI interfered with the mitochondrial redox state in perfused livers leading to more oxidized mitochondria. This effect was reflected by a significant decrease in the mitochondrial NADH/NAD+ ratios from basal values of 0.40 +/- 0.04 to 0.28 +/- 0.02 within 10 min following the infusion of ddI. In suspensions of isolated mitochondria utilizing succinate as a substrate, ddI diminished state 3 and stimulated state 4 respiration significantly, suggesting an uncoupling effect by ddI. Incubation of mitochondria with ddI resulted in a significant decrease in the mitochondrial respiratory control ratios (state 3/state 4 respiration) to 0.8 +/- 0.02 from corresponding control values of 6.0 +/- 0.40 Data also show that ddI inhibited mitochondrial DNA synthesis as evidenced by the decrease in [3H]thymidine incorporation into mitochondrial DNA. This study confirms the need for a close monitoring of patients receiving the dideoxyinosine anti-AIDS drugs and for prompt discontinuation of these drugs before potential irreversible liver damage occurs.