Prevalence, complications, and hospital charges associated with use of bone-morphogenetic proteins in spinal fusion procedures

Runx2 overexpression in bone marrow stromal cells accelerates bone formation in critical-sized femoral defects

The repair of large nonunions in long bones remains a significant clinical problem due to high failure rates and limited tissue availability for auto- and allografts. Many cell-based strategies for healing bone defects deliver bone marrow stromal cells (BMSCs) to the defect site to take advantage of the inherent osteogenic capacity of this cell type. However, many factors, including donor age and ex vivo expansion of the cells, cause BMSCs to lose their differentiation ability. To overcome these limitations, we have genetically engineered BMSCs to constitutively overexpress the osteoblast-specific transcription factor Runx2. In the present study, we examined Runx2-modified BMSCs, delivered via polycaprolactone scaffolds loaded with type I collagen meshes, in critical-sized segmental defects in rats compared to unmodified cells, cell-free scaffolds, and empty defects. Runx2 expression in BMSCs accelerated healing of critical-sized defects compared to unmodified BMSCs and defects receiving cell-free treatments. These findings provide an accelerated method for healing large bone defects, which may reduce recovery time and the need for external fixation of critical-sized defects.

Recombinant human bone morphogenetic protein-2 and pancreatic cancer: a retrospective cohort study

PURPOSE

To assess whether use of recombinant human bone morphogenetic protein-2 (rhBMP-2) during lumbar spinal fusion surgery affects subsequent risk of pancreatic cancer.

METHODS

Using US Medicare claims data, we performed a retrospective cohort study of patients who underwent lumbar spinal fusion surgery between October 2003 and December 2005. The study population, all >66 years, was identified from procedure codes for lumbar fusion. Claims for a bone morphogenetic protein (BMP) served as a proxy for rhBMP-2 exposure (another BMP product shared the same code). Pancreatic cancer was identified from claims indicating this diagnosis and cancer-specific therapy. We used Cox proportional hazard regression to estimate hazard ratios (HRs) and 95%CIs.

RESULTS

Of the 93,654 patients in the study, the mean age was 75 years, and 16.5% had claims for BMP. During a mean 1.4 years of follow-up, 91 patients were diagnosed with pancreatic cancer (eight in the BMP- and 83 in the non-BMP cohort). Consistent with previous research, pancreatic cancer was associated with older age, male gender, black race, and diabetes mellitus. Compared to those who did not receive BMP, patients exposed to BMP were not at increased risk of pancreatic cancer (adjusted HR=0.70, 95%CI: 0.34-1.45). A chart review substudy validated the exposure measure; 52/55 patients with claims for BMP received rhBMP-2.

CONCLUSIONS

In this large study of elderly patients who underwent lumbar fusion surgery, exposure to BMP was not associated with an increased risk of pancreatic cancer.

The evolution of rhPDGF-BB in musculoskeletal repair and its role in foot and ankle fusion surgery

Platelet-derived growth factor (PDGF) is one of the most thoroughly studied proteins in the body. Research has progressively highlighted the role of PDGF during wound healing and in the bone repair cascade. This research has resulted in FDA approval of 2 products containing a recombinant version of the protein, rhPDGF-BB, for treating chronic diabetic foot ulcers and periodontal bone defects. This article reviews the applicable basic science and mechanisms of action of PDGF, with attention to the increasingly defined role of rhPDGF-BB in initiating bone regeneration. The most recent data from prospective clinical trials evaluating the use of rhPDGF-BB in combination with beta tricalcium phosphate as a substitute for autogenous bone graft in hindfoot and ankle arthrodesis are also summarized.

Hydrogel microsphere encapsulation of a cell-based gene therapy system increases cell survival of injected cells, transgene expression, and bone volume in a model of heterotopic ossification

Bone morphogenetic proteins (BMPs) are well known for their osteoinductive activity, yet harnessing this capacity remains a high-priority research focus. We present a novel technology that delivers high BMP-2 levels at targeted locations for rapid endochondral bone formation, enhancing our preexisting cell-based gene therapy system by microencapsulating adenovirus-transduced cells in nondegradable poly(ethylene glycol) diacrylate (PEGDA) hydrogels before intramuscular delivery. This study evaluates the in vitro and in vivo viability, gene expression, and bone formation from transgenic fibroblasts encapsulated in PEGDA microspheres. Fluorescent viability and cytotoxicity assays demonstrated >95% viability in microencapsulated cells. ELISA and alkaline phosphatase assays established that BMP-2 secretion and specific activity from microencapsulated AdBMP2-transduced fibroblasts were not statistically different from monolayer. Longitudinal transgene expression studies of AdDsRed-transduced fibroblasts, followed through live animal optical fluorescent imaging, showed that microencapsulated cells expressed longer than unencapsulated cells. When comparable numbers of microencapsulated AdBMP2-transduced cells were intramuscularly injected into mice, microcomputed tomography evaluation demonstrated that the resultant heterotopic bone formation was approximately twice the volume of unencapsulated cells. The data suggest that microencapsulation protects cells and prolongs and spatially distributes transgene expression. Thus, incorporation of PEGDA hydrogels significantly advances current gene therapy bone repair approaches.

Skeletal stem cells and bone regeneration: translational strategies from bench to clinic

Clinical imperatives for new bone to replace or restore the function of traumatized or bone lost as a consequence of age or disease has led to the need for therapies or procedures to generate bone for skeletal applications. Tissue regeneration promises to deliver specifiable replacement tissues and the prospect of efficacious alternative therapies for orthopaedic applications such as non-union fractures, healing of critical sized segmental defects and regeneration of articular cartilage in degenerative joint diseases. In this paper we review the current understanding of the continuum of cell development from skeletal stem cells, osteoprogenitors through to mature osteoblasts and the role of the matrix microenvironment, vasculature and factors that control their fate and plasticity in skeletal regeneration. Critically, this review addresses in vitro and in vivo models to investigate laboratory and clinical based strategies for the development of new technologies for skeletal repair and the key translational points to clinical success. The application of developmental paradigms of musculoskeletal tissue formation specifically, understanding developmental biology of bone formation particularly in the adult context of injury and disease will, we propose, offer new insights into skeletal cell biology and tissue regeneration allowing for the critical integration of stem cell science, tissue engineering and clinical applications. Such interdisciplinary, iterative approaches will be critical in taking patient aspirations to clinical reality.

Challenges to bone formation in spinal fusion

Spinal arthrodesis continues to expand in clinical indications and surgical practice. Despite a century of study, failure of bone formation or pseudarthrosis can occur in individual patients with debilitating clinical symptoms. Here we review biological and technical aspects of spinal fusion under active investigation, describe relevant biomechanics in health and disease, and identify the possibilities and limitations of translational animal models. The purpose of this article is to foster collaborative efforts with researchers who model bone hierarchy. The induction of heterotopic osteosynthesis requires a complex balance of biologic factors and operative technique to achieve successful fusion. Anatomical considerations of each spinal region including blood supply, osteology, and biomechanics predispose a fusion site to robust or insufficient bone formation. Careful preparation of the fusion site and appropriate selection of graft materials remains critical but is sometimes guided by conflicting evidence from the long-bone literature. Modern techniques of graft site preparation and instrumentation have evolved for every segment of the vertebral column. Despite validated biomechanical studies of modern instrumentation, a correlation with superior clinical outcomes is difficult to demonstrate. In many cases, adjuvant biologic therapies with allograft and synthetic cages have been used successfully to reproduce the enhancement of fusion rates observed with cancellous and tricortical autograft. Current areas of investigation comprise materials science, stem cell therapies, recombinant growth factors, scaffolds and biologic delivery systems, and minimally invasive surgical techniques to optimize the biologic response to intervention. Diverse animal models are required to approach the breadth of spinal pathology and novel therapeutics.

Bone grafting options for lumbar spine surgery: a review examining clinical efficacy and complications

Background

Iliac crest harvest has been considered the “gold standard” at producing successful arthrodesis of the lumbar spine but is also associated with many donor-site morbidities. Many alternatives have been used to avoid iliac crest harvest, including autologous bone from other donor sites, allogeneic bone, ceramics, and recombinant human bone morphogenetic proteins (rhBMPs). This review will highlight the properties and preparations of these graft types and their potential complications and reported clinical efficacy.

Methods

A Medline search was conducted via PubMed by use of the following terms in various combinations: lumbar fusion, freeze-dried allograft, fresh-frozen allograft, autograft, iliac crest, demineralized bone matrix, rhBMP-2, rhBMP-7, scoliosis, bone marrow aspirate, HEALOS, coralline hydroxyapatite, beta tricalcium phosphate, synthetic, ceramics, spinal fusion, PLF, PLIF, ALIF, and TLIF. Only articles written in English were assessed for appropriate material. Related articles were also assessed depending on the content of articles found in the original literature search.

Conclusions

Although iliac crest remains the gold standard, reported success with alternative approaches, especially in combination, has shown promise. Stronger evidence with limited sources of potential bias is necessary to provide a clear picture of their clinical efficacy.

The enhancement of bone allograft incorporation by the local delivery of the sphingosine 1-phosphate receptor targeted drug FTY720

Poor vascularization coupled with mechanical instability is the leading cause of post-operative complications and poor functional prognosis of massive bone allografts. To address this limitation, we designed a novel continuous polymer coating system to provide sustained localized delivery of pharmacological agent, FTY720, a selective agonist for sphingosine 1-phosphate receptors, within massive tibial defects. In vitro drug release studies validated 64% loading efficiency with complete release of compound following 14 days. Mechanical evaluation following six weeks of healing suggested significant enhancement of mechanical stability in FTY720 treatment groups compared with unloaded controls. Furthermore, superior osseous integration across the host-graft interface, significant enhancement in smooth muscle cell investment, and reduction in leukocyte recruitment was evident in FTY720 treated groups compared with untreated groups. Using this approach, we can capitalize on the existing mechanical and biomaterial properties of devitalized bone, add a controllable delivery system while maintaining overall porous structure, and deliver a small molecule compound to constitutively target vascular remodeling, osseous remodeling, and minimize fibrous encapsulation within the allograft-host bone interface. Such results support continued evaluation of drug-eluting allografts as a viable strategy to improve functional outcome and long-term success of massive cortical allograft implants.

Off-label use of bone morphogenetic proteins in the United States using administrative data

STUDY DESIGN

Epidemiological study using national administrative data.

OBJECTIVE

To evaluate the temporal trends in on-label and off-label bone morphogenetic protein (BMP) usage in primary and revision spine fusion by spine region and surgical approach, and nonspine applications in the United States from 2002 to 2007.

SUMMARY OF BACKGROUND DATA

The prevalence of BMP usage for spine fusion has been on the rise, but its use has not been stratified by surgical approach, particularly for lumbar fusion where it has only been Food And Drug Administration-approved for anterior lumbar interbody fusion (ALIF).

METHODS

The prevalence of BMP usage in the United States was evaluated using the Nationwide Inpatient Sample between October 1, 2002 and December 31, 2007. The Nationwide Inpatient Sample is the single largest all-payer inpatient care database in the United States. The principal procedure associated with BMP use was determined, and the prevalence of BMP use was calculated for various population subgroups.

RESULTS

A total of 340,251 inpatient procedures with BMP usage were identified. Between 2003 and 2007, the annual number of procedures involving BMP increased by 4.3-fold from 23,900 to 103,194. Spine fusion accounted for the vast majority (92.8%) of principal procedures with BMP. The predominant use of BMP was in primary posterior lumbar interbody fusion or transforaminal lumbar interbody fusion (PLIF/TLIF) (30.0%), followed by primary posterolateral spine fusion (20.4%), primary ALIF (16.6%), primary cervical fusions (13.6%), and primary thoracolumbar fusions (3.9%). Of primary ALIF with BMP, 19.3% did not involve the implantation of an interbody device.

CONCLUSION

At least 85% of principal procedures using BMP were for off-label applications. With uncertainty regarding the risks of using BMP in certain off-label applications, further research will be needed to better define the appropriate indications. Our study also demonstrates that disparities in the differential rates of BMP use exist in the spine fusion population.

Can bone morphogenetic protein binding peptide increase efficiency of bone formation?

STUDY DESIGN

The role of bone morphogenetic protein binding peptide (BBP) in bone formation is reviewed from basic science studies and potential clinical application.

OBJECTIVE

We review the discovery and early scientific studies of BBP with emphasis on potential future clinical applications.

SUMMARY OF BACKGROUND DATA

Biologics delivered locally to enhance bone formation are of increasing importance, particularly in spinal fusion. The most useful agents currently available are bone morphogenetic proteins (BMPs). The indications for recombinant human BMP are expanding; however, certain disadvantages including high costs, unwanted ectopic bone formation, and local inflammatory reaction are becoming more prevalent. As a result, alternate strategies are being developed to provide safer, less expensive, and more efficacious adjuvant agents.

METHODS

This study reviews the existing published data and early experimental results, and explores potential clinical applications of BBP.

RESULTS

BBP is a specific binding protein for BMP with an intermediate affinity, which makes it an ideal "slow release" agent.

CONCLUSION

BBP may reduce the time to fusion and more thoroughly control the distribution of bone healing in spinal fusion. Further study is ongoing to explore clinical applications.

Comparison of 5766 vertebral compression fractures treated with or without kyphoplasty

BACKGROUND

The majority of the 700,000 osteoporotic vertebral compression fractures (VCFs) that occur annually in the United States affect women. The total treatment costs exceed $17 billion and approximate the total costs of breast cancer ($13 billion) and heart disease ($19 billion). Balloon-assisted percutaneous vertebral augmentation with bone cement (kyphoplasty) reportedly reduces VCF-related pain and accelerates return of independent functional mobility. Kyphoplasty may decrease overall cost of VCF treatment costs by reducing use of posttreatment medical resources.

QUESTIONS/PURPOSES

We evaluated complications, mortality, posthospital disposition, and treatment costs of kyphoplasty compared with nonoperative treatment using the Nationwide Inpatient Sample database.

METHODS

We identified 5766 VCFs (71% female) in patients 65 years of age or older with nonneoplastic VCF as the primary diagnosis in nonroutine hospital admissions; 15.3% underwent kyphoplasty. Demographic data, medical comorbidities, and fracture treatment type were recorded. Outcomes, including complications, mortality, posthospital disposition, and treatment costs, were compared for each treatment type.

RESULTS

Women were more likely to be treated with kyphoplasty than were men. Patients undergoing kyphoplasty had comorbidity indices equivalent to those treated nonoperatively. Kyphoplasty was associated with a greater likelihood of routine discharge to home (38.4% versus 21.0% for nonoperative treatment), a lower rate of discharge to skilled nursing (26.1% versus 34.8%) or other facilities (35.7% versus 47.1%), a complication rate equivalent to nonoperative treatment (1.7% versus 1.0%), and a lower rate of in-hospital mortality (0.3% versus 1.6%). Kyphoplasty was associated with higher cost of hospitalization (mean $37,231 versus $20,112).

CONCLUSIONS

Kyphoplasty for treatment of VCF in well-selected patients may accelerate the return of independent patient function as indicated by improved measures of hospital discharge. The initially higher cost of treatment may be offset by the reduced use of posthospital medical resources.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Perioperative complications with rhBMP-2 in transforaminal lumbar interbody fusion

Bone morphogenetic protein (BMP) is commonly used as an ICBG substitute for transforaminal lumbar interbody spine fusion (TLIF). However, multiple recent reports have raised concerns regarding a substantial incidence of perioperative radiculopathy. Also, given the serious complications reported with anterior cervical BMP use, risks related to swelling and edema with TLIF need to be clarified. As TLIF related complications with rhBMP-2 have generally been reported in small series or isolated cases, without a clear denominator, actual complication rates are largely unknown. The purpose this study is to characterize perioperative complications and complication rates in a large consecutive series of TLIF procedures with rhBMP-2. We reviewed inpatient and outpatient medical records for a consecutive series of 204 patients [113 females, 91 males, mean age 49.3 (22-79) years] who underwent TLIF using rhBMP-2 between 2003 and 2007. Complications observed within a 3-month perioperative interval were categorized as to etiology and severity. Wound problems were delineated as wound infection, hematoma/seroma or persistent drainage/superficial dehiscence. Neurologic deficits and radiculopathies were analyzed to determine the presence of a clear etiology (screw misplacement) and identify any potential relationship to rhBMP-2 usage. Complications were observed in 47 of 204 patients (21.6%) during the 3-month perioperative period. Major complications occurred in 13 patients (6.4%) and minor complications in 34 patients (16.7%). New or more severe postoperative neurologic complaints were noted in 13 patients (6.4%), 6 of whom required additional surgery. These cases included one malpositioned pedicle screw and one epidural hematoma. In four patients (2.0%), localized seroma/hematoma in the area of the foramen caused neural compression, and required revision. In one additional patient, vertebral osteolysis caused foraminal narrowing and radiculopathy, but resolved without further surgery. Persistent radiculopathy without clear etiology on imaging studies was seen in six patients. Wound related problems were seen in six patients (2.9%), distributed as wound infection (3), hematoma/seroma (1) and persistent drainage/dehiscence (2). Overall, this study demonstrates a modest complication rate for TLIF using rhBMP-2. While perioperative complications which appeared specific to BMP usage were noted, they occurred infrequently. It will be necessary to weigh this incidence of complications against the complication rate associated with ICBG harvest and any differential benefit in obtaining a solid arthrodesis.

The long-term results of anterior surgical reconstruction in patients with postlaminectomy cervical kyphosis

BACKGROUND CONTEXT

Postlaminectomy kyphosis of the cervical spine is a challenging condition to treat because it has a combination of an exposed cord, progressive kyphosis, segmental instability, and anterior neural compression. The ideal mode of surgical correction remains controversial. In terms of surgical strategy, there are few large series that have reported the long-term results of anterior surgical treatment of this condition.

PURPOSE

This study was designed to determine the long-term results and outcomes of anterior surgical treatment alone for the patients of postlaminectomy cervical kyphosis.

STUDY DESIGN/SETTING

This is a retrospective review of prospectively collected data in an academic institution.

PATIENT SAMPLE

The sample comprises 23 patients who underwent anterior reconstruction surgery for the treatment of postlaminectomy kyphosis.

OUTCOME MEASURES

The outcome measures were neck disability index (NDI), visual analog scale (VAS) for neck and arm pain, Nurick grades, kyphosis angles, fusion status, and complications.

METHODS

Two independent spine surgeons reviewed the completed medical records and radiographs of 23 patients who had undergone multilevel anterior cervical hybrid decompression (corpectomy and discectomy) with instrumented fusions for postlaminectomy kyphosis by one surgeon at an academic institution. The clinical and radiographic outcomes were measured by NDI, VAS for neck and arm pain, Nurick grades, kyphosis angles, and fusion status at the time of preoperative, postoperative, and the last follow-up.

RESULTS

The mean follow-up was 44.5+/-31.0 months (range 24-120 months). The average preoperative kyphosis of 20.9 degrees was significantly improved to a lordosis of 14.0 degrees after surgery (p<.0001) and was maintained to a lordosis of 9.6 degrees at the final follow-up (p<.0001). The average correction angle of kyphosis was 30.5+/-11.7 degrees . The average preoperative, NDI, VAS, and Nurick grades were significantly improved at the last follow-up (all, p<.0001). The average levels of 0.9+/-0.7 corpectomy, 2.0+/-0.9 discectomy, and 3.8+/-1.4 anterior fusions were performed in each patient. Solid fusion was confirmed by computed tomography in all patients at a mean time of 3.8+/-1.2 months. There were six (26%) patients and seven (30.4%) complications: four (14.3%) graft-related complications (one implant displacement, one graft dislodgment, and one pseudarthrosis), one swallowing difficulty, one wound infection, one dura tear, and one pneumonia.

CONCLUSIONS

Our data suggest that multilevel anterior surgical treatment using hybrid decompression (corpectomy and discectomy) combined with instrumented fusion yields acceptable clinical and neurological improvement and effective correction of cervical kyphosis. The techniques used also appeared to decrease the incidence of graft-related complications compared with a previous report by the same author.

Complications related to osteobiologics use in spine surgery: a systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

The objectives of this systematic review were to identify the character and rates of complications in patients after the use of BMP in spine fusion surgery and to determine whether there is a dose-response relationship of BMP with complications.

SUMMARY OF BACKGROUND DATA

BMP is used on-label for ALIF with LT-CAGE and off-label for various spine fusion applications in the cervical, thoracic, and lumbar spines because of its effectiveness in promoting arthrodesis. Multiple studies published over the past several years have highlighted complications associated with BMP in a variety of clinical fusion scenarios. There are no systematic reviews on this topic, and thus, the complication profile of off-label use or physician directed use of BMP in spinal fusion surgery is not well characterized. Some of the reported complications are unique to BMP, which underscores the need for this thorough literature review.

METHODS

A systematic review of the English language literature was performed for articles published between 1990 and June 2009. Electronic databases and reference lists of key articles were searched to identify articles examining the use of BMP in spine surgery. Two independent reviewers assessed the level of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria and disagreements were resolved by consensus.

RESULTS

Two hundred forty-' articles that assessed outcomes after BMP use in spinal surgery were identified from the literature; of these, 31 articles were selected for inclusion. We determined that multiple complications are associated after the use of rhBMP-2 in both cervical and lumbar spine fusion surgery. There is a mean incidence of 44%, 25%, and 27% of resorption, subsidence, and interbody cage migration reported for lumbar spine interbody fusion surgery although reoperation or long-term detrimental effect was rare. Cervical studies report a mean 5.8% of postoperative soft tissue problems, including dysphagia, when rhBMP-2 is used for ventral cervical fusion. It was determined that the strength of evidence of the peer-reviewed literature that report on types of complications is high for the lumbar and low for the cervical spine, respectively, and that the current strength of evidence on rates of complications with BMP is moderate and low, respectively.

CONCLUSION

The complication profile of BMP-2 for ALIF with LT-CAGE is well characterized. Because of the lack of substantive data, the same is not true for other types of lumbar fusions, or for cervical or thoracic fusion applications. BMP has been associated with a variety of unique complications in the ventral cervical and lumbar spines. The published data on BMP fail to precisely profile this product's use in fusion surgery; hence, it should be used only after a careful consideration of the relevant data. Well-designed and executed studies are necessary to completely define the incidence of various complications relative to type of BMP, type and region of fusion, surgical technique, dose, and carrier, and importantly, to define the natural history and management of associated complications.

Fusion versus disk replacement for degenerative conditions of the lumbar and cervical spine: quid est testimonium?

This article compares the outcomes following spinal fusion and disk replacement for degenerative conditions of the lumbar and cervical spine. The short-term outcomes of lumbar and cervical total disk replacement are equivalent to that following spinal fusion. Long-term follow-up studies of total disk replacement are necessary to confirm its potential benefit in reducing or preventing adjacent level degeneration. Also discussed is the philosophy of the surgical management of degenerative conditions of the lumbar and cervical spine.

Outcome of lumbar arthrodesis in patients sixty-five years of age or older. Surgical technique

BACKGROUND

The value of lumbar spine arthrodesis in older patients is not well documented. As most of the literature regarding lumbar arthrodesis in older patients has focused on the prevalence of complications, the purpose of this study was to determine the clinical outcomes for older compared with younger patients undergoing lumbar arthrodesis.

METHODS

We studied 224 patients who underwent a single-level posterolateral lumbar arthrodesis with an iliac crest bone graft. Outcome measures included the Oswestry Disability Index, the Medical Outcomes Study Short Form-36 and numeric rating scales for back and leg pain, as well as a radiographic assessment of fusion. Outcome measures were evaluated on the basis of the mean change and the percentage of patients reaching a minimum clinically important difference threshold. For comparison, the patients were divided into two groups: 174 patients who were younger than sixty-five years and fifty patients who were sixty-five years of age or older.

RESULTS

Substantial improvements from baseline were noted in all of the clinical and health-related quality-of-life measures at the six-month, one-year, and two-year intervals. The mean improvements in the Oswestry Disability Index score at two years postoperatively were 28.5 points for the older patients and 24.5 points for the younger patients. For Short Form-36 physical component summary scores, the mean improvement from baseline was 14.2 points for the older group and 11.7 points for the younger group at two years. The older patients also demonstrated a similar or greater improvement in the numeric rating scale back and leg pain scores at all time intervals, with a significant difference in leg pain scores at two years postoperatively (10.4 points for the older patients and 6.4 points for the younger patients; p=0.002). Perioperative complications, although an obvious concern, did not appear to adversely affect clinical and health-related quality-of-life outcomes at two years postoperatively.

CONCLUSIONS

This study demonstrates a substantial benefit for patients sixty-five years of age or older with degenerative disc disease who are treated with a single-level lumbar decompression and instrumented arthrodesis, and we conclude that lumbar arthrodesis is a viable and reasonable treatment option for appropriately selected patients sixty-five years of age or older.

Spine care: evaluation of the efficacy and cost of emerging technology

Over the last decade a number of new technologies have been introduced to the area of spine care. Although this recent explosion of innovation has brought advances to patient care, it has also brought concerns regarding overuse, increasing costs, and safety. A value-based approach to assessing and purchasing new technology depends on a shift toward comparative effectiveness analysis, transparency in pricing and potential conflicts of interest, and an alignment of incentives and goals among purchasers, consumers, and payers. How to assess the effectiveness of new technology in patient care is an unresolved issue for any cost-effectiveness analysis, as models traditionally used to assess medical therapies (ie, quality-adjusted life years) may not be directly applicable to analysis of surgical intervention. Spine surgeons must be involved in multidisciplinary collaborative efforts to develop models of efficacy analysis and to direct outcomes-based research to appropriately evaluate the benefits of surgical interventions and new technologies.

Bone morphogenetic proteins in orthopaedic surgery

Bone healing is a predictable process that has a high rate of success. For some patients, and in certain clinical settings, this process can be delayed or completely inhibited. This leads to significant morbidity and may also result in time lost from work, costs related to prolonged medical treatment, and continued pain at the site of nonunion or failed spinal fusion. Several growth factors, specifically BMP-2 and BMP-7, have been approved in several countries for specific indications. The use of these products and potential complications of their use are reviewed.