Iatrogenic muscle damage in transforaminal lumbar interbody fusion and adjacent segment degeneration: a comparative finite element analysis of open and minimally invasive surgeries.

PURPOSE: Lumbar procedures for Transforaminal Lumbar Interbody Fusion (TLIF) range from open (OS) to minimally invasive surgeries (MIS) to preserve paraspinal musculature. We quantify the biomechanics of cross-sectional area (CSA) reduction of paraspinal muscles following TLIF on the adjacent segments. METHODS: ROM was acquired from a thoracolumbar ribcage finite element (FE) model across each FSU for flexion-extension. A L4-L5 TLIF model was created. The ROM in the TLIF model was used to predict muscle forces via OpenSim. Muscle fiber CSA at L4 and L5 were reduced from 4.8%, 20.7%, and 90% to simulate muscle damage. The predicted muscle forces and ROM were applied to the TLIF model for flexion-extension. Stresses were recorded for each model. RESULTS: Increased ROM was present at the cephalad (L3-L4) and L2-L3 level in the TLIF model compared to the intact model. Graded changes in paraspinal muscles were seen, the largest being in the quadratus lumborum and multifidus. Likewise, intradiscal pressures and annulus stresses at the cephalad level increased with increasing CSA reduction. CONCLUSIONS: CSA reduction during the TLIF procedure can lead to adjacent segment alterations in the spinal element stresses and potential for continued back pain, postoperatively. Therefore, minimally invasive techniques may benefit the patient.

Comparison of the safety outcomes between two surgical approaches for anterior lumbar fusion surgery: anterior lumbar interbody fusion (ALIF) and extreme lateral interbody fusion (ELIF).

PURPOSE: To review the evidence on safety of anterior lumbar interbody fusion (ALIF) and extreme lateral transpsoas interbody fusion (ELIF) in the treatment of degenerative spinal disorders with an emphasis on the association between neuromonitoring and complications. METHODS: We performed a systematic literature search in the Cochrane (CENTRAL), MEDLINE, EMBASE and the FDA Medical Devices databases. We abstracted information on study design, sample size, population, procedure, number and location of involved levels, follow-up time and complications, as well as information on conflict of interest and source of funding. In addition, for ELIF we collected information on the use of neuromonitoring during the procedure. RESULTS: 34 publications were included in the review: 24 ELIF (all case series), 9 ALIF (8 randomized controlled trials and 1 case series) and one retrospective cohort that directly compared ELIF with ALIF. 18 out of 24 ELIF studies reported using neuromonitoring. The overall complication rate for ELIF was lower compared to ALIF without FDA reports (16.61 vs. 26.47 %, respectively). However, the rate of neurologic complications in ELIF was almost twice as high compared to ALIF without FDA reports (8.92 and 4.96 %, respectively). The rate of overall complications in ELIF studies that were reported using neuromonitoring was lower compared to the studies that did not report using neuromonitoring (16.34 vs. 21.74 %, respectively). CONCLUSION: Although the overall complications rate for ELIF was lower compared to ALIF, ELIF is associated with a greater risk of neurological complications compared to ALIF even when used with neuromonitoring.

Treating the Aging Spine.

Demographic trends make it incumbent on orthopaedic spine surgeons to recognize the special challenges involved in caring for older patients with spine pathology. Unique pathologies, such as osteoporosis and degenerative deformities, must be recognized and treated. Recent treatment options and recommendations for the medical optimization of bone health include vitamin D and calcium supplementation, diphosphonates, and teriparatide. Optimizing spinal fixation in elderly patients who have osteoporosis is critical; cement augmentation of pedicle screws is promising. In the management of geriatric odontoid fractures, nonsurgical support with a collar may be considered for low-demand patients, whereas surgical fixation is favored for high-demand patients. Management of degenerative deformity must address sagittal plane balance, which includes consideration of pelvic incidence. Various osteotomies may prove helpful in this setting.

Extending public health: the Rockefeller Sanitary Commission and hookworm in the American South.

The Rockefeller Sanitary Commission for the Eradication of Hookworm Disease (1909-1914) fielded a philanthropic public health project that had three goals: to estimate hookworm prevalence in the American South, provide treatment, and eradicate the disease. Activities covered 11 Southern states, and Rockefeller teams found that about 40% of the population surveyed was infected. However, the commission met strong resistance and lacked the time and resources to achieve universal county coverage and meet project goals. We explore how these constraints triggered project changes that systematically reshaped project operations and the characteristics of the counties surveyed and treated. We show that county selectivity reduced the project's initial potential to affect hookworm prevalence estimates, treatment, and eradication in the American South.

Evaluating the biomechanical effects of pedicle subtraction osteotomy at different lumbar levels: a finite element investigation.

BACKGROUND: Pedicle subtraction osteotomy (PSO) is effective for correcting spinal malalignment but is associated with high complication rates. The biomechanical effect of different PSO levels remains unclear, and no finite element (FE) analysis has compared L2-, L3-, L4-, and L5-PSOs. PURPOSE: To assess the effects of PSO level on the spine's global range of motion, stresses on posterior instrumentation, load sharing with the anterior column, and proximal junctional stresses. STUDY DESIGN: A computational biomechanical analysis. METHODS: A validated 3D spinopelvic FE model (T10-Pelvis) was used to perform PSOs at L2, L3, L4 and L5. Each model was instrumented with a 4-rod configuration (primary rods + in-line satellite rods) from T11-Pelvis. Simulation included a 2-step analysis; (1) applying 300 N to thoracic, 400 N to lumbar, and 400 N to sacrum, and (2) applying a 7.5 Nm moment to the top endplate of the T10 vertebral body. Acetabulum surfaces were fixed in all degrees of freedom. The range of motion, spinopelvic parameters (lumbar lordosis [LL], sacral slope [SS], pelvic incidence [PI], and pelvic tilt [PT]), PSO force, and von Mises stresses were measured. All models were compared with the L3-PSO model and percentage differences were captured. RESULTS: Compared to the intact alignment: LL increased by 48%, 45%, 59%, and 56% in the L2-, L3-, L4-, and L5-PSO models; SS increased by 25%, 15%, and 11% while PT decreased by 76%, 53%, and 45% in L2-, L3-, and L4-PSOs (SS and PT approximated intact model in L5-PSO); Lumbar osteotomy did not affect the PI. Compared to L3-PSO: L2-, L4-, and L5-PSOs showed up to 32%, 34%, and 34% lower global ROM. The least T10-T11 ROM was observed in L5-PSO. The left and right SIJ ROM were approximately similar in each model. Amongst all, the L5-PSO model showed the least ROM at the SIJ. Compared to L3-PSO, the L2-, L4-, and L5-PSO models showed up to 67%, 61%, and 78% reduced stresses at the UIV, respectively. Minimum stress at UIV+ was observed in the L3-PSO model. The L2-and L3-PSOs showed the maximum PSO force. The L5-PSO model showed the lowest stresses on the primary rods in all motions. CONCLUSION: Our FE investigation indicates that L5-PSO results in the greatest lumbar lordosis and lowest global, SIJ, and T10-T11 ROMs and stresses on the primary rods, suggesting potential mechanical benefits in reducing the risk of rod breakage. However, L4- and L5-PSOs led to the least force across the osteotomy site, which may increase the risk of pseudarthrosis. These findings provide biomechanical insights that may inform surgical planning, though further clinical investigation is essential to determine the optimal PSO level and validate these results. CLINICAL SIGNIFICANCE: Understanding the biomechanical impact of PSO level is crucial for optimizing surgical outcomes and minimizing the risks of postoperative complications.

Vascularized fibular grafts in patients with avascular necrosis of femoral head: a systematic review and meta-analysis.

BACKGROUND: Vascularized fibular grafting (VFG) has been initiated to treat avascular necrosis of the femoral head (ANFH) since the late 1970s. There are a number of review articles updating the use of VFG to treat the ANFH. None of them applied statistical analysis for combining results from different studies to obtain a quantitative estimate of the overall effect and potential harm of VFG in comparison to other treatment. METHODS: Several electronic databases were searched to find studies using VFG to treat ANFH. The outcomes sought included Harris Score, failure rate (conversion to total hip arthroplasty (THA) and/or femoral head collapse), and complications rate. Included studies were assessed for methodological bias and estimates of effect were calculated. Potential reasons for heterogeneity were explored. RESULTS: The clinical results of 69.0 % of VFG-treated patients and 25.0 % of non-VFG-treated patients were good to excellent (OR 0.13; p < 0.01). The conversion rate to THA of VFG-treated and that of other methods treated hips was 16.5 % and 42.6 % (OR 0.19; p < 0.001). Collapse rate of VFG-treated and that of non-VFG-treated hips was 16.7 % and 63.6 % (OR 0.09; p < 0.05). The complication rate of VFG-treated and that of other methods treated patients was 23.8 % and 8.9 % (OR 3.44; p = 0.09). For Steinberg stage I, II ANFH, failure rate of VFG-treated and that of non-VFG-treated hips was 9.8 % and 40.2 % (OR 0.17; p < 0.001). For Steinberg stage II, III ANFH, failure rate of VFG-treated and that of non-VFG-treated hips was 16.5 % and 42.8 %, respectively (OR 0.17; p < 0.001). CONCLUSIONS: VFG is a justified method that can prevent the ANFH from progressing to collapse, and that can retard or avoid hip replacement, especially in the hips of Steinberg stage I, II, and III.

Electocatalytic water oxidation by cobalt(III) hangman ß-octafluoro corroles.

Cobalt hangman corrole, bearing ß-octafluoro and meso-pentafluorophenyl substituents, is an active water splitting catalyst. When immobilized in Nafion films, the turnover frequencies for the 4e(-)/4H(+) process at the single cobalt center of the hangman platform approach 1 s(-1). The pH dependence of the water splitting reaction suggests a proton-coupled electron transfer (PCET) catalytic mechanism.

Hangman corroles: efficient synthesis and oxygen reaction chemistry.

The construction of a new class of compounds--the hangman corroles--is provided efficiently by the modification of macrocyclic forming reactions from bilanes. Hangman cobalt corroles are furnished in good yields from a one-pot condensation of dipyrromethane with the aldehyde of a xanthene spacer followed by metal insertion using microwave irradiation. In high oxidation states, X-band EPR spectra and DFT calculations of cobalt corrole axially ligated by chloride are consistent with the description of a Co(III) center residing in the one-electron oxidized corrole macrocycle. These high oxidation states are likely accessed in the activation of O-O bonds. Along these lines, we show that the proton-donating group of the hangman platform works in concert with the redox properties of the corrole to enhance the catalytic activity of O-O bond activation. The hangman corroles show enhanced activity for the selective reduction of oxygen to water as compared to their unmodified counterparts. The oxygen adduct, prior to oxygen reduction, is characterized by EPR and absorption spectroscopy.

Regiospecific quenching of a photoexcited platinum(II) complex at acidic and basic sites.

The carbometalated complex Pt(dppzφ*)Cl, where dppzφ* denotes the 6-(4-tert-butylphenyl)-dipyrido[3,2-a:2',3'-c]phenazine ligand, exhibits emission in a dichloromethane solution at room temperature with a concentration-dependent excited-state lifetime. Extrapolation to zero Pt(dppzφ*)Cl concentration yields a limiting lifetime of 11.0 µs in the absence of dioxygen along with an impressive emission quantum yield of 0.17. The visible absorption of Pt(dppzφ*)Cl has intraligand charge-transfer as well as metal-to-ligand charge-transfer character, but the oscillator strength may derive, in part, from π-π* excitation within the phenazine moiety. An intriguing aspect of the Pt(dppzφ*)Cl system is that its reactive excited state is subject to regiospecific quenching by Lewis bases and hydrogen-bonding Lewis acids. Base-induced quenching involves an attack at the platinum center. The rate constant increases with the donor strength of the quencher and reaches the order of 10(8) M(-1) s(-1) with a relatively strong base like dimethyl sulfoxide. The orbital parentage of the excited state probably influences the quenching rates by affecting the charge density at platinum, as well as at the phenazine nitrogen atoms, where attack by Lewis acids occurs. With mildly acidic alcohols like 1,1,1,3,3,3-hexafluoropropan-2-ol and 2,2,2-trifluoroethanol, high concentrations of the quencher are necessary to suppress the emission. Carboxylic acids are stronger quenchers, and the quenching constant increases with the acid strength according to tabulated pK(a) values. Cyanoacetic acid exhibits the highest measured quenching rate constant (2.6 × 10(9) M(-1) s(-1)), which only decreases 30% when the acid is in the (NC)CH(2)CO(2)D form. A weaker acid, CH(3)CO(2)H, exhibits an even smaller kinetic isotope effect. Literature comparisons suggest that acid-induced quenching probably involves hydrogen-bond formation as opposed to net proton transfer.

The treatment of symptomatic osteoporotic spinal compression fractures.

This clinical practice guideline is based on a series of systematic reviews of published studies on the treatment of symptomatic osteoporotic spinal compression fractures. Of 11 recommendations, one is strong; one, moderate; three, weak; and six, inconclusive. The strong recommendation is against the use of vertebroplasty to treat the fractures; the moderate recommendation is for the use of calcitonin for 4 weeks following the onset of fracture. The weak recommendations address the use of ibandronate and strontium ranelate to prevent additional symptomatic fractures, the use of L2 nerve root blocks to treat the pain associated with L3 or L4 fractures, and the use of kyphoplasty to treat symptomatic fractures in patients who are neurologically intact.

The Effects of NPY1 Receptor Antagonism on Intervertebral Disc and Bone Changes in Ovariectomized Rats.

STUDY DESIGN: Basic science. OBJECTIVE: To compare the effects of a neuropeptide Y1 receptor antagonist (NPY-1RA) to estrogen on maintaining vertebral bone microarchitecture and disc height in a rat model of menopause. METHODS: This study was an institutional animal care approved randomized control study with 104 ovariectomized rats and 32 intact control animals. Comparison of disc height, trabecular bone, body weights, circulating levels of NPY and estrogen, and distribution of Y1 receptors in the intervertebral disc in an established rodent osteoporotic model were made at baseline and after 2, 4, and 8 weeks after receiving either an implant containing estrogen or an antagonist to the neuropeptide Y1 receptor. Data was compared statistically using One-way analysis of variance. RESULTS: Circulating levels of estrogen increased and NPY decreased following estrogen replacement, with values comparable to ovary-intact animals. NPY-1RA-treated animals had low estrogen and high NPY circulating levels and were similar to ovariectomized control rats. Both NPY-1RA and estrogen administration were able reduce, menopause associated weight gain. NPY-1RA appeared to restore bone formation and maintain disc height, while estrogen replacement prevented further bone loss. CONCLUSION: NPY-1RA in osteoporotic rats activates osteoblast production of bone and decreased marrow and body fat more effectively than estrogen replacement when delivered in similar concentrations. Annulus cells had NPY receptors, which may play a role in disc nutrition, extracellular matrix production, and pain signaling cascades.

Cervical Spine Fusion: Biomechanics of a Three-Level Cadaver Model Comparing Anterior Plate versus Stand-Alone Cage.

Study Design-Biomechanical cadaveric study. Objective-Long anterior cervical plate and cage (APC) constructs have a risk of pseudarthrosis with minor bone resorption. Stand-alone cages (SACs) allow settling. The biomechanics of SAC have been investigated, but not multilevel, compression screw SAC. The purpose of this study is to evaluate the biomechanical safety of three-level SAC versus APC. Methods-Discectomies at three levels of five human cadaver spines (T1-C3) were fixed with SAC. A 0.18 mm thick shim was interposed between the cage and the superior endplate, and a pressure transducer map was placed between the cage and the inferior endplate. Tests were performed in flexion-extension and then repeated after removing the shims to simulate minor bone resorption. Subsequently, APC was applied and experiments were repeated. The pressure between each cage and endplate and motion of the implants were measured. Results-The range of motion (ROM) of SAC and APC constructs were comparable. The contact area and pressure between cage and endplate did not significantly change during motion with SAC. Shim removal did not significantly affect ROM, contact area, or average pressure measures. For APC, both contact area and pressure decreased from extension to flexion. Shim removal caused a significant loss of contact area and pressure. Conclusions-SAC provided comparable rigidity to the conventional APC construct while maintaining compression at the endplate-cage interface throughout flexion-extension and after minor bone resorption.

Longer follow-up continues to reveal no increased risk of cancer with the use of recombinant human bone morphogenetic protein in spine fusion.

BACKGROUND CONTEXT: Large observational studies on potential oncogenic effects of recombinant human bone morphogenetic protein (rhBMP) in spine fusion surgery are limited by relatively short follow-up times. PURPOSE: To study the possible association between rhBMP and cancer risk in a long-term follow-up study. STUDY DESIGN: A retrospective cohort study using a combination of the Washington State Comprehensive Hospital Abstract Reporting System, the Washington State Cancer Registry, State of Washington death certificates, and the Washington State Department of Licensing. PATIENT SAMPLE: Participants were adults age ≥21 years who underwent spine fusion surgery enhanced by rhBMP for degenerative spine disease between January 1, 2002 and December 31, 2010. A comparison group matching each patient receiving rhBMP with three patients not receiving rhBMP was created using the indicators of age, sex, and year of treatment. We excluded patients receiving spine fusion for vertebral fractures or infection, and those with a diagnosis of cancer before or at the index procedure. OUTCOME MEASURES: The primary outcome was the first diagnosis of any cancer as identified in the records of the state cancer registry or death certificate through the end of 2015. METHODS: We compared cancer risk between those receiving spine fusion with and without rhBMP using survival analysis. We calculated incidence rates (hazards) by computing the ratio of the number of events and total time at risk. Unadjusted hazard ratios (HR) and adjusted HR (aHR) and their respective 95% confidence intervals (CI) were calculated assuming a Cox proportional hazard regression model. We adjusted the model to include the site of surgery (lumbar vs. cervical) as a covariate as this differed in frequency between the two treatment groups. To assess whether rhBMP adversely affects the progression of cancer, we compared mortality between rhBMP users and nonusers in those who developed cancer. Research support toward this study was received from Medtronic Sofamor Danek USA. The investigators alone, and not Medtronic, were solely responsible for the design, conduct, analysis, and reporting of this study. RESULTS: We included 16,914 patients who had spine fusion, of whom 4,246 received rhBMP. During the study period, 1,342 patients were diagnosed with some form of cancer. The incidence rate was similar between the two groups: 11.2 per 1,000 person years in the rhBMP group and 10.4 per 1,000 person years in the non-rhBMP group, with an aHR of 0.96; 95% CI, 0.85 to 1.10. Similarly, rhBMP use was not associated with an increased risk of commonly occurring individual cancer types, nor with cancer specific mortality after a cancer diagnosis, aHR, 0.92; 95% CI, 0.69 to 1.22. CONCLUSIONS: Long-term follow-up confirms previous findings that rhBMP application treated with elective spinal fusion did not result in an increased cancer risk in a large population of US adults.

Contact Sports as a Risk Factor for Amyotrophic Lateral Sclerosis: A Systematic Review.

STUDY DESIGN: Systematic review. INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease, ultimately resulting in paralysis and death. The condition is considered to be caused by a complex interaction between environmental and genetic factors. Although vast genetic research has deciphered many of the molecular factors in ALS pathogenesis, the environmental factors have remained largely unknown. Recent evidence suggests that participation in certain types of sporting activities are associated with increased risk for ALS. OBJECTIVE: To test the hypothesis that competitive sports at the highest level that involve repetitive concussive head and cervical spinal trauma result in an increased risk of ALS compared with the general population or nonsport controls. METHODS: Electronic databases from inception to November 22, 2017 and reference lists of key articles were searched to identify studies meeting inclusion criteria. RESULTS: Sixteen studies met the inclusion criteria. Sports assessed (professional or nonprofessional) included soccer (n = 5), American football (n = 2), basketball (n = 1), cycling (n = 1), marathon or triathlon (n = 1), skating (n = 1), and general sports not specified (n = 11). Soccer and American football were considered sports involving repetitive concussive head and cervical spinal trauma. Professional sports prone to repetitive concussive head and cervical spinal trauma were associated with substantially greater effects (pooled rate ratio [RR] 8.52, 95% CI 5.18-14.0) compared with (a) nonprofessional sports prone to repetitive concussive head and cervical spinal trauma (pooled RR 0.60, 95% CI 0.12-3.06); (b) professional sports not prone to repetitive head and neck trauma (pooled RR 1.35, 95% CI 0.67-2.71); or (c) nonprofessional sports not prone to repetitive concussive head and cervical spinal trauma (pooled RR 1.17, 95% CI 0.79-1.71). CONCLUSIONS: Our review suggests that increased susceptibility to ALS is significantly and independently associated with 2 factors: professional sports and sports prone to repetitive concussive head and cervical spinal trauma. Their combination resulted in an additive effect, further increasing this association to ALS.

Does Operative or Nonoperative Treatment Achieve Better Results in A3 and A4 Spinal Fractures Without Neurological Deficit?: Systematic Literature Review With Meta-Analysis.

STUDY DESIGN: Systematic literature review with meta-analysis. OBJECTIVE: Thoracolumbar (TL) fractures can be treated conservatively or surgically. Especially, the treatment strategy for incomplete and complete TL burst fractures (A3 and A4, AOSpine classification) in neurologically intact patients remains controversial. The aim of this work was to collate the clinical evidence on the respective treatment modalities. METHODS: Searches were performed in PubMed and the Web of Science. Clinical and radiological outcome data were collected. For studies comparing operative with nonoperative treatment, the standardized mean differences (SMD) for disability and pain were calculated and methodological quality and risk of bias were assessed. RESULTS: From 1929 initial matches, 12 were eligible. Four of these compared surgical with conservative treatment. A comparative analysis of radiological results was not possible due to a lack of uniform reporting. Differences in clinical outcomes at follow-up were small, both between studies and between treatment groups. The SMD was 0.00 (95% CI -0.072, 0.72) for disability and -0.05 (95% CI -0.91, 0.81) for pain. Methodological quality was high in most studies and no evidence of publication bias was revealed. CONCLUSIONS: We did not find differences in disability or pain outcomes between operative and nonoperative treatment of A3 and A4 TL fractures in neurologically intact patients. Notwithstanding, the available scores have been developed and validated for degenerative diseases; thus, their suitability in trauma may be questionable. Specific and uniform outcome parameters need to be defined and enforced for the evaluation of TL trauma.

Using a configurable EMR and decision support tools to promote process integration for routine HIV screening in the emergency department.

Given the clinical and public health benefits of routine Human Immunodeficiency Virus (HIV) testing in the emergency department (ED) and Centers for Disease Control and Prevention recommendations, Maricopa Medical Center, as part of Maricopa Integrated Health System, started Test, Educate, Support, and Treat Arizona (TESTAZ) and became the first and, to-date, only hospital in Arizona to implement routine, non-targeted, opt-out, rapid HIV screening in the ED. The authors describe the implementation of a universal, routine, opt-out HIV screening program in the adult ED of an urban safety-net hospital serving under-served populations, including the uninsured and under-insured. Through a controlled and collaborative process, the authors integrated custom documentation elements specific to HIV screening into the triage/intake process, implemented and utilized clinical decision support tools to guide clinicians in each step of the process, and used electronic data collection and reporting to drive new screening protocols that led to a significant increase in overall HIV testing rates.

The Risk of Cancer With the Use of Recombinant Human Bone Morphogenetic Protein in Spine Fusion.

STUDY DESIGN: Retrospective cohort study using the Washington State Comprehensive Hospital Abstract Reporting System, the Washington State Cancer Registry, and Washington State death certificates. OBJECTIVE: To study the possible association between recombinant human bone morphogenetic protein (rhBMP) and cancer risk. SUMMARY OF BACKGROUND DATA: The use of rhBMP in spine fusion surgery remains controversial with respect to its possible role in tumorigenesis. METHODS: We compared adults who underwent spine fusion for degenerative disease with and without rhBMP between 2002 and 2010. Patients were matched on the basis of age, sex, and year of treatment. We excluded patients with a diagnosis of cancer before or at the index procedure. The primary outcome was the first diagnosis of cancer as identified in the records of the cancer registry. RESULTS: We included 16,914 patients who had spine fusion, of whom 4246 received rhBMP. During the study period, 449 patients received a diagnosis of cancer: 117 (2.76% of 4246) in the rhBMP group and 332 (2.62% of 12 668) in the no rhBMP group. The incidence rate was similar between the rhBMP and no rhBMP 9.5 and 9.0 per 1000 person years, respectively (hazard ratio, 1.06; 95% confidence interval, 0.86-1.30). There were no differences in the rate of cancer between the two groups in subgroups defined on the basis of site of fusion or surgical method. CONCLUSION: There was no increase in overall cancer incidence among those receiving rhBMP. An important limitation of this and other studies of rhBMP and cancer that have been conducted to date is their relatively limited duration of follow-up. The examination of cancer incidence following rhBMP administration must continue beyond just the first several years to adequately assess the potential of rhBMP to influence the occurrence of one or more types of malignancy. LEVEL OF EVIDENCE: 3.

Catastrophic Cervical Spine Injuries in Contact Sports.

Study Design Systematic review. Objectives To determine the incidence of catastrophic cervical spine injuries (CCSIs) among elite athletes participating in contact team sports and whether the incidence varies depending on the use of protective gear or by player position. Methods Electronic databases and reference lists of key articles published from January 1, 2000, to January 29, 2016, were searched. Results Fourteen studies were included that reported CCSI in rugby (n = 10), American football (n = 3), and Irish hurling (n = 1). Among Rugby Union players, incidence of CCSI was 4.1 per 100,000 player-hours. Among National Football League players, the CCSI rate was 0.6 per 100,000 player-exposures. At the collegiate level, the CCSI rate ranged from 1.1 to 4.7 per 100,000 player-years. Mixed populations of elite and recreational rugby players in four studies report a CCSI rate of 1.4 to 7.2 per 100,000 player-years. In this same population, the scrum accounted for 30 to 51% of total reported CCSIs in Rugby Union versus 0 to 4% in Rugby League. The tackle accounted for 29 to 39% of injuries in Rugby Union and 78 to 100% of injuries in Rugby League. Making a tackle was responsible for 29 to 80% of injuries in American football. Conclusion CCSIs are infrequent among elite athletes. There is insufficient evidence to determine the effect of protective gear (e.g., helmets, padding) on CCSI incidence. Scrum and tackle in rugby and tackling in American football account for the majority of CCSIs in each respective sport.