Biomedical subjects

Alan Hilibrand

Publications and source records attributed to Alan Hilibrand.

11 recordsLinked to original sources

PubMed2005

Comparison of OP-1 Putty (rhBMP-7) to iliac crest autograft for posterolateral lumbar arthrodesis: a minimum 2-year follow-up pilot study.

STUDY DESIGN: A prospective, randomized, controlled, multicenter clinical study. OBJECTIVE: To compare the safety and clinical and radiographic outcomes of OP-1 (BMP-7) Putty to autogenous iliac crest bone graft in a population of patients undergoing laminectomy and posterolateral fusion for symptomatic lumbar stenosis associated with degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Although the existing preclinical and clinical data suggest that OP-1 is able to achieve osteoinduction and clinical fusion in a variety of situations, the efficacy of this recombinant protein in a clinical spine fusion population has not been fully elucidated. This study directly compares the efficacy and safety of OP-1 putty to autograft bone for arthrodesis in patients with symptomatic stenosis in association with degenerative spondylolisthesis. METHODS: Thirty-six patients with degenerative lumbar spondylolisthesis and symptoms of neurogenic claudication underwent laminectomy, bilateral medial facetectomy, and posterolateral fusion using either iliac crest autograft or OP-1 Putty. Oswestry scores and SF-36 questionnaires were used to determine the clinical response to treatment. Independent, blinded neuroradiologists reviewed both static and dynamic radiographs to determine the fusion status. Successful fusion was declared whenthe presence of continuous bridging bone between the transverse processes was observed and less than 5 degrees of angular motion and 2 mm of translational movement was measured using digital calipers. RESULTS: Efficacy data were tabulated for 27 patients at the 24-month time point and an additional 4 patients (without evaluable 24-month results) at the 36-month time point. One patient was not evaluable for radiology, so the data reflect clinical information for 31 patients and radiology for 30 patients. Clinical success, defined as a 20% improvement in the preoperative Oswestry score, was achieved by 17 of 20 (85%) OP-1 Putty patients and 7 of 11 (64%) autograft patients. A successful posterolateral fusion was achieved in 11 of 20 (55%) OP-1 Putty patients and 4 of 10 (40%) autograft patients. SF-36 scores showed similar clinical improvement in both groups. No systemic toxicity, ectopic bone formation, recurrent stenosis, or other adverse events specifically related to the use of the OP-1 Putty implant were observed. CONCLUSION: This study represents the first clinical trial to demonstrate the safety and similarity of OP-1 Putty as a replacement for autogenous bone graft in the posterolateral fusion environment with a minimum of 2-year follow-up. OP-1 Putty was able to achieve osteoinduction leading to a radiographically solid fusion in the absence of autogenous iliac crest bone graft in 55% of the patients at 24 and 36 months. These results compare favorably to the historical fusion rates reported for uninstrumented arthrodesis in this challenging clinical scenario.

Adult↗

PubMed2005

Variation in surgical decision making for degenerative spinal disorders. Part II: cervical spine.

STUDY DESIGN: Survey-based descriptive study. OBJECTIVE: To study relationships between surgeon-specific factors and surgical approach to degenerative diseases of the cervical spine. SUMMARY OF BACKGROUND DATA: Geographic variations in the rates of cervical spine surgery are significant within the United States. Although surgeon density correlates with the rates of spinal surgery, other reasons for variation such as surgeon-specific factors are poorly understood. METHODS: A total of 22 orthopedic surgeons and 8 neurosurgeons of varied ages and geographic regions answered questions regarding the need for surgery, surgical approach, and use of fusion and instrumentation for 5 simulated cases. Cases included: (1) single-level disc herniation with osteophyte and radiculopathy, (2) single-level pseudarthrosis with axial neck pain, (3) multilevel stenosis with radiculopathy and neutral lordosis, (4) multilevel stenosis with myelopathy and neutral lordosis, and (5) multilevel stenosis with myelopathy and marked kyphosis. The effects of surgeon age and training background on surgical decision making were analyzed using an independent samples t test and Fisher exact test, respectively. RESULTS: The greatest agreement occurred for the single-level disc herniation, with all surgeons choosing an anterior discectomy, and 28 of the 29 respondents recommending fusion. Younger surgeons recommended instrumentation more often for all cases, reaching significance for the case of multilevel stenosis with myelopathy and neutral lordosis (Fisher exact test P = 0.02). Differences in recommendation for fusion, instrumentation, and the use of a posterior approach between orthopedic and neurosurgeons were limited. CONCLUSIONS: Variations in surgical procedures for cervical degenerative disease may depend on the clinical condition. Although this study found strong agreement in treatment approach to single-level disc herniation, significant variation was seen for the other degenerative conditions of the cervical spine. While differences in recommendation for fusion were not clearly associated with surgeon age, there was a trend toward the higher use of instrumentation by younger surgeons. Previously documented geographic variation may result in part from a lack of consensus regarding appropriate treatment techniques for certain degenerative conditions of the cervical spine, as well as surgeon-specific factors.

Adult↗

PubMed2005

Variation in surgical decision making for degenerative spinal disorders. Part I: lumbar spine.

STUDY DESIGN: Survey-based descriptive study. OBJECTIVE: To study relationships between surgeon-specific factors and surgical approach to degenerative diseases of the lumbar spine. SUMMARY OF BACKGROUND DATA: Geographic variations in the rates of lumbar spine surgery are significant within the United States. Although surgeon density correlates with the rates of spine surgery, other reasons for variation such as surgeon age and training background are poorly understood. METHODS: A total of 22 orthopedic surgeons and 8 neurosurgeons of varied ages and geographic regions answered questions regarding the need for surgery, surgical approach, and use of fusion and instrumentation for 5 simulated cases. Cases included: (1) multilevel stenosis without deformity or instability, (2) degenerative spondylolisthesis with stenosis, (3) isthmic (spondylolytic) spondylolisthesis with foraminal stenosis, (4) degenerative scoliosis with stenosis, and (5) recurrent stenosis following prior laminectomy without deformity or instability. The effects of surgeon age and training background on surgical decision making were analyzed using an independent samples t test and Fisher exact test, respectively. RESULTS: Significant variation in treatment approach among surgeons was noted for all cases except the patient with lytic spondylolisthesis, for whom all surgeons recommended fusion. Orthopedists recommended fusion and instrumentation more often than neurosurgeons for all cases, reaching significance for degenerative scoliosis with stenosis (P = 0.02 for both fusion and instrumentation). Younger surgeons were generally more likely to recommend instrumentation than their older peers, reaching significance for multilevel stenosis without deformity or instability and recurrent stenosis following prior laminectomy without deformity or instability (P = 0.05 and 0.01, respectively). CONCLUSIONS: Variations in surgical approach to lumbar degenerative diseases may depend on a patient's clinical condition. This study found strong agreement in the approach to lytic spondylolisthesis but significant variation for other degenerative conditions of the lumbar spine. In addition, recommendation for fusion and instrumentation varied with surgeon age and training background. Previously documented geographic variations may result in part from a lack of consensus on appropriate treatment techniques for specific lumbar degenerative conditions, as well as surgeon-specific factors.

Adult↗

PubMed2005

A 2-year follow-up pilot study evaluating the safety and efficacy of op-1 putty (rhbmp-7) as an adjunct to iliac crest autograft in posterolateral lumbar fusions.

The ability of bone morphogenetic proteins (BMPs) to induce bone formation has led to a multitude of investigations into their use as bone graft substitutes in spinal surgery. The purpose of this multi-center clinical pilot study was to evaluate the safety and efficacy of BMP-7 (osteogenic protein 1, OP-1), in the form of a putty, combined with autograft for intertransverse process fusion of the lumbar spine in patients with symptomatic spinal stenosis and degenerative spondylolisthesis following spinal decompression. Twelve patients with spinal stenosis and degenerative lumbar spondylolisthesis underwent a laminectomy and partial or complete medial facetectomy as required for decompression of the neural elements, followed by an intertransverse process fusion by placing iliac crest autograft and OP-1 putty between the decorticated transverse processes. No instrumentation was used. Patients were followed clinically using the Oswestry scale and SF-36 outcome forms, and radiographically using static and dynamic radiographs to assess their fusion status over a 2-year period. Independent and blinded radiologists assessed the films for the presence of bridging bone between the transverse processes and measured translation and angulation on dynamic films using digital calipers. Radiographic outcome was compared to a historical control (autograft alone fusion without instrumentation for the treatment of degenerative spondylolisthesis). All adverse events were recorded prospectively. The results showed eight of the nine evaluable patients (89%) obtained at least a 20% improvement in their preoperative Oswestry score, while five of ten patients (50%) with radiographic follow-up achieved a solid fusion by the criteria used in this study. Bridging bone on the anteroposterior film was observed in seven of the ten patients (70%). No systemic toxicity, ectopic bone formation, recurrent stenosis or other adverse events related to the OP-1 putty implant were observed. A successful fusion was observed in slightly over half the patients in this study, using stringent criteria without adjunctive spinal instrumentation. This study did not demonstrate the statistical superiority of OP-1 combined with autograft over an autograft alone historical control, in which the fusion rate was 45%. There were no adverse events related to the OP-1 putty implant in this study, which supports findings in other studies suggesting the safety of bone morphogenetic proteins in spinal surgery.

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PubMed2004

A pilot study evaluating the safety and efficacy of OP-1 Putty (rhBMP-7) as a replacement for iliac crest autograft in posterolateral lumbar arthrodesis for degenerative spondylolisthesis.

STUDY DESIGN: A prospective, randomized, controlled, multicenter clinical study was conducted. OBJECTIVE: To compare the clinical and radiographic outcomes of patients treated with OP-1 (BMP-7) Putty to autogenous iliac crest bone graft for one-level uninstrumented posterolateral fusion of the lumbar spine following decompressive laminectomy for the treatment of symptomatic degenerative spondylolisthesis with spinal stenosis. BACKGROUND: Preclinical studies have demonstrated that osteoinductive recombinant human osteogenic protein 1 in the form of OP-1 Putty is successful at achieving a posterolateral fusion in rabbits and dogs without any significant safety concerns. METHODS: Thirty-six patients with degenerative lumbar spondylolisthesis and symptoms of neurogenic claudication were randomized (2:1) to either OP-1 Putty (3.5 mg of OP-1 per side) or autogenous iliac crest bone graft for one-level uninstrumented posterolateral fusion following a decompressive laminectomy. Enrollment in the study was complete when 24 OP-1 Putty patients and 12 autograft patients had been randomized and treated. A patient administered Oswestry scale and SF-36 scale were used to determine clinical outcomes. Independent, blinded neuroradiologists reviewed both static and dynamic radiographs to determine fusion status. RESULTS: At the 1-year follow-up, 32 patients were available for clinical analysis and 29 patients were available for radiographic review. Clinical success as measured on the Oswestry scale was achieved by 18 of 21 (86%) OP-1 Putty patients and 8 of 11 (73%) autograft patients. SF-36 pain index scores showed similar results. Fourteen of 19 (74%) OP-1 Putty patients and 6 of 10 (60%) autograft patients achieved a successful posterolateral fusion fulfilling all fusion criteria. Of the 29 evaluable patients, 15 were both clinical and radiographic successes, 5 were radiographic successes but were clinical failures, 1 patient was both a radiographic and clinical failure, and 8 patients were radiographic failures but were clinical successes. No systemic toxicity, ectopic bone formation, recurrent stenosis, or other adverse events related to the OP-1 Putty implant were observed. CONCLUSION: Although the posterolateral spine is a challenging fusion environment in patients with degenerative spondylolisthesis, successful radiographic fusion was obtained using OP-1 Putty at a rate that was similar to autograft given the number of patients in this study. Importantly, there were no apparent adverse consequences related to the use of the OP-1 Putty implant in this patient population.

Adult↗

PubMed2003

A pilot safety and efficacy study of OP-1 putty (rhBMP-7) as an adjunct to iliac crest autograft in posterolateral lumbar fusions.

The ability of bone morphogenetic proteins (BMPs) to induce bone formation has led to an increasing interest in the potential for their use in fusion surgery. The purpose of this multi-center clinical pilot study was to evaluate the safety of one such BMP-osteogenic protein 1, in the form of OP-1 putty-combined with autograft for intertransverse process fusion of the lumbar spine in patients with symptomatic spinal stenosis and degenerative spondylolisthesis following spinal decompression. Twelve patients with spinal stenosis and degenerative lumbar spondylolisthesis underwent laminectomy and partial or complete medial facetectomy as required for decompression of the neural elements followed by intertransverse process fusion by placing iliac crest autograft and OP-1 putty between the decorticated transverse processes. No instrumentation was used. Patients were followed clinically using the Oswestry scale and radiographically using static and dynamic radiographs to assess their fusion status. Independent and blinded radiologists assessed the films for the presence of bridging bone between the transverse processes and measured translation and angulation on dynamic films using digital calipers. In addition to bridging bone, less than or equal to 5 degrees of angular motion and less than or equal to 2 mm of translation were required to classify the patients as successfully fused, as per the definition of successful fusion provided by the FDA for use in clinical trials involving investigational devices to attain spinal fusion. Radiographic outcome was compared to a historical control (autograft alone fusion without instrumentation for the treatment of degenerative spondylolisthesis). All adverse events were recorded prospectively. The results showed 9 of the 12 patients (75%) obtained at least a 20% improvement in their preoperative Oswestry score, while 6 of 11 patients (55%) with radiographic follow-up achieved a solid fusion by the criteria used in this study. Bridging bone on the anteroposterior film was observed in 10 of the 11 patients (91%). No systemic toxicity, ectopic bone formation, recurrent stenosis or other adverse events related to the OP-1 putty implant were observed. A successful fusion was observed in slightly over half the patients in this study, using stringent criteria without adjunctive spinal instrumentation. This study did not demonstrate the superiority of OP-1 combined with autograft over an autograft alone historical control, in which the fusion rate was approximately 45%. The lack of adverse events related to the OP-1 putty implant in this study is in agreement with other studies supporting the safety of bone morphogenetic proteins in spinal surgery.

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PubMed2003

Physical and monetary costs associated with autogenous bone graft harvesting.

Although autogenous iliac bone is frequently used for bone graft, many well-documented complications are associated with this procedure-including chronic pain; nerve, arterial, and ureteral injury; herniation of abdominal contents; sacroiliac joint instability; pelvic fractures; hematoma; and infection. An understanding of the morbidities associated with bone graft harvesting and of the strategies for avoiding them is imperative for surgeons using this grafting source. In addition, although synthetic grafting materials are considered relatively expensive compared with autogenous sources, the majority of physicians are unaware of the actual direct and indirect costs associated with autogenous bone graft harvesting. Contemporary allograft and synthetic grafting composites are being developed to optimize and surpass the native qualities of autogenous sources (ie, osteogenesis, osteoinductivity, osteoconductivity). Careful comparison of the cost of these alternative sources with the physical and monetary costs of autogenous bone graft will undoubtedly make allograft, recombinant, synthetic graft composites the logical choice in the very near future.

Anesthesia↗

PubMed2002

Comparative gene expression profiling of normal and degenerative discs: analysis of a rabbit annular laceration model.

STUDY DESIGN: A rabbit annular laceration model was used to investigate intervertebral disc gene expression in normal and lacerated discs. OBJECTIVES: To determine and compare the pattern of expression of potentially important genes in normal and lacerated discs and to determine if the changes in gene expression were similar to human degenerative discs. SUMMARY OF BACKGROUND DATA: Little is known regarding gene expression in normal or degenerating disc tissue. METHODS: Eighteen rabbits were subjected to annular laceration of the L1-L2 and L2-L3 discs while two rabbits served as sham controls. Control and lacerated discs were harvested 1 week, 3 weeks, and 6 weeks following surgery and subjected to histologic examination and gene expression analysis using the reverse transcription-polymerase chain reaction (RT-PCR). The genes studied included collagen Type I (Col I), collagen Type II (Col II), decorin, fibronectin (FN), interleukin-1a (IL-1alpha), bone morphogenetic protein 2 (BMP-2), Fas, matrix metalloproteinase 1 (MMP-1), matrix metalloproteinase 9 (MMP-9), matrix metalloproteinase 13 (MMP-13), and tumor necrosis factor (TNF). Expression levels of each gene were normalized to that of glyceraldehyde-3-phosphate dehydrogenase (GADPH), a constitutively expressed gene. RESULTS: Histology confirmed progressive degeneration of the discs over the 6-week study period. Different patterns of gene expression were observed in control and lesioned discs. Annular laceration caused a marked upregulation (two- to eightfold) of the expression of Col I, Col II, FN, MMP-1, MMP-9, MMP-13, and Fas genes, whereas that of BMP-2, IL-1alpha, and TNF genes was unaffected. Expression of the decorin gene was downregulated approximately sixfold after annular laceration. CONCLUSION: Annular laceration in this animal model resulted in marked changes in gene expression. Upregulation of gene expression was observed for some molecules found at high concentration in human degenerated discs, suggesting similarities to human disc degeneration at the molecular level. This supports the need for further study of the genes found to be activated by annular laceration.

Animals↗

PubMed2002

Use of a bioabsorbable anterior cervical plate in the treatment of cervical degenerative and traumatic disc disruption.

OBJECT: Anterior cervical discectomy and fusion (ACDF) is a widely accepted treatment for anterior degenerative or traumatic instability of the cervical spine. To reduce or eliminate complications such as implant migration and failure, imaging degradation, and fusion stress shielding that are occasionally associated with spinal instrumentation, attention has been given to the use of bioresorbable anterior cervical plate (ACP) devices. This paper is a preliminary report of a retrospective series in which a resorbable mesh and screw system was used for graft containment in single-level ACDF. METHODS: A review of patient charts and imaging studies was conducted to determine functional outcome, fusion success, and potential soft-tissue reaction to implant resorption. Nine patients with a cervical degenerative disc disease or traumatic disc disruption were treated between October 2001 and March 2002. Follow up averaged 206 days. Eight patients were found to have an excellent result, one patient had a good result, and no patients had a satisfactory or poor result. At the time of follow-up examination, 77% of patients were found to have a radiographically solid fusion. The two patients without a solid fusion were examined only an average 8 months postoperatively and manifested no symptoms related to fusion nonhealing. No significant soft-tissue reaction was noted clinically or radiographically in any of the patients. CONCLUSIONS: The results of this preliminary study indicate that bioresorbable ACP systems for single-level ACDF are both safe and effective.

Absorbable Implants↗

PubMed2002

Use of a bioabsorbable anterior cervical plate in the treatment of cervical degenerative and traumatic disk disruption.

Anterior cervical diskectomy and fusion is a widely accepted treatment for anterior management of degenerative or traumatic instability of the cervical spine. To reduce or eliminate complications such as implant migration and failure, imaging degradation, and fusion stress shielding that are occasionally associated with spinal instrumentation, attention has been given to the use of bioresorbable anterior cervical plating devices. This paper is a preliminary report of a retrospective series in which a resorbable mesh and screw system (OS Reconstructive Mesh, MacroPore Biosurgery Inc, San Diego, Calif) was used for graft containment in single-level anterior cervical diskectomy and fusion. A review of patient charts and imaging studies was conducted to determine functional outcome, fusion success, and potential soft-tissue reaction to implant resorption. Nine patients with a diagnosis of cervical degenerative disk disease or traumatic disk disruption were treated between October 2001 and March 2002. Follow-up averaged 206 days. Eight patients were found to have an excellent result, one patient had a good result, and no patients had a satisfactory or poor result. At the time of follow-up, 77% of patients (7/9) were found to have a radiographically solid fusion. The two patients without a solid fusion were only on average 8 months out from their fusion procedure and manifested no symptoms related to fusion nonhealing. No significant soft-tissue reaction was noted clinically or radiographically in any of the patients. The results of this preliminary study indicate that bioresorbable anterior cervical plating for single-level anterior cervical diskectomy and fusion is both safe and effective.

Absorbable Implants↗

PubMedDate not supplied

Percutaneous vertebral augmentation.

BACKGROUND CONTEXT: With the aging of the population, painful osteoporotic compression fractures are becoming more common. PURPOSE: To review the physiologic implications of these injuries as well as treatment options and outcomes, especially with reference to newer, percutaneous "augmentation" procedures, that is, vertebroplasty and kyphoplasty. STUDY DESIGN/SETTING: A literature review. METHODS: No direct, randomized studies comparing vertebroplasty, kyphoplasty and standard, nonoperative care are available. RESULTS: The growing literature suggests a role for kyphoplasty and vertebroplasty in the management of patients with intractable pain or progressive vertebral collapse after vertebral compression fracture. Both procedures likely offer similar rates of pain relief. Kyphoplasty, although more expensive, may allow fracture reduction. The void created with the balloon tamp allows a more viscous cement to be applied, thereby decreasing the risk of extravasation. CONCLUSIONS: More study is required to understand the ideal role of these new techniques in the management of spinal osteoporosis and associated fractures. However, for carefully selected cases, current data suggest that the complication rates are low and pain relief can be profound.

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