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PubMed1999

Osteoinductive bone graft substitutes for spinal fusion: a basic science summary.

An understanding of precise biologic mechanisms at work during spinal fusion healing is just beginning to evolve. Current molecular biology research has shown this process to be multifactorial and extremely complex. With the advent of improved animal models to study the biology of spinal fusion, essential information regarding the basic science behind arthrodesis has advanced knowledge of this process. Moreover, with advances in local gene therapy as well as osteoinductive proteins and osteoinductive carrier matrices, the orthopedic surgeon will soon enter into a new era of biologic manipulation for fusion.

Animals↗

PubMed1998

Spinal fusion and pedicle screw instrumentation in the treatment of spondylolisthesis over the age of 60.

BACKGROUND: Spinal fusion or instrumentation for the treatment of spondylolisthesis in elderly people is still an issue of controversy. The purpose of this study was to assess the clinical results of laminectomy, posterolateral fusion, and pedicle screw instrumentation in patients over age 60. MATERIALS AND METHODS: From 1993 through 1994, 94 spondylolisthesis patients over age 60 underwent laminectomy, posterolateral fusion and pedicle screw instrumentation. All the patients had follow-up examinations 3 months, 6 months, 1 year and then annually after the operation. At each follow-up visit, the clinical results and complications were evaluated and a radiographic assessment was performed. The follow-up period ranged from 2 to 4 years. At the final follow-up visit, we administered a questionnaire designed for clinical evaluation. RESULTS: Seventy-five patients (80%) obtained improvement in back pain, 75 patients (80%) got improvement in leg pain, and 65 patients (69%) needed no medications. The average distance the patients were able to walk, at one time was 2.2 km. Sixty-seven patients (71%) could walk more than 500 m at a time. Seventy-four patients (79%) showed solid fusion, 20 patients inadequate fusion, and no psuedoarthrosis was found. Complications were rare. CONCLUSION: Laminectomy with spinal fusion and instrumentation is a good method for the treatment of spondylolisthesis in elderly people, and it can achieve a satisfactory clinical outcome.

Age Factors↗

PubMed2004

Implant removal for late-developing infection after instrumented posterior spinal fusion for scoliosis: reinstrumentation reduces loss of correction. A retrospective analysis of 45 cases.

A retrospective follow-up study of patients who, having undergone instrumented posterior spinal fusion for scoliosis, experienced late infection and then underwent either implant removal alone or implant removal and instrumented refusion. We conducted this study to determine whether it is possible to avoid loss of correction by a single-stage implant removal and reinstrumentation procedure. There have been a few reports of late-appearing infections after spinal instrumentation. Implant bulk, metallurgic reactions, and contamination with low-virulence microorganisms have been suggested as possible etiologic factors. The clinical symptoms include pain, swelling, redness, and spontaneous drainage of fluid. Complete instrumentation removal and systemic antibiotics is usually curative. We retrospectively reviewed 45 patients who underwent instrumented posterior spinal fusion for scoliosis and experienced development of late infections and, after a mean of 3 years after the initial procedure, either underwent implant removal alone [ n=35, instrumentation removal (HR) group] or additionally underwent reinstrumentation and fusion [ n=10, reinstrumentation and fusion (RI&F) group]. Three patients were reinstrumented 1.5 years after instrumentation removal, and seven underwent a one-stage rod removal and reinstrumentation/refusion procedure. Allergic predisposition, protracted postoperative fever, and pseudarthrosis appear to increase the risk of late-developing infection after posterior spinal fusion. All wounds in both groups healed uneventfully. Preoperative radiographic Cobb measurements showed no statistically significant between-group differences. At follow-up, however, outcome was clearly better in the RI&F group: Loss of correction was significantly smaller in reinstrumented patients. Thus, the thoracic Cobb angle was 28+/-16 degrees (range 0-55 degrees ) in the RI&F group versus 42+/-15 degrees (21-80 degrees ) in the HR group, and the lumbar Cobb angle was 22+/-11 degrees (10-36 degrees ) in the RI&F group versus 29+/-12 degrees (13-54 degrees ) in the HR group. The results of our study demonstrate that wound healing is usually uneventful after instrumentation removal for late infection, also when patients undergo instrumented refusion in a one-stage procedure. Reinstrumentation appears to achieve permanent correction of scoliosis.

Adolescent↗

PubMed2004

Spinal fusion surgery: animal models for tissue-engineered bone constructs.

Animal models have been used extensively to investigate the biology of fracture healing and spinal fusion. The goal of each spinal fusion model is to try and reproduce the correct sequence of events during osseous healing in humans. Animal models allow us the capability of dialing in fusion rates and fusion parameters depending upon the study conditions. These models have become invaluable in assessing the clinical potential of emerging technologies such as recombinant growth factors and gene therapy.

Animals↗

PubMed2026

Comparison of posterior cellular bonegraft options for single-level lumbar spinal fusion: a randomized trial.

BACKGROUND: Iliac bone autograft (IBG) is osteoinductive/osteogenic/osteoconductive but requires an additional harvesting procedure with known morbidities. Bone morphogenic protein (BMP) is osteoinductive and effective in obtaining fusion but is used off label for posterior fusion, has multiple side effects, and is expensive. Stem cell bone products, both auto- and allograft are attractive osteoinductive alternatives that avoid morbidity related to the graft donor site and may have a better safety profile than BMP. Morcelized allograft bone is osteoconductive but not osteoinductive or osteogenic. PURPOSE: Evaluate and compare the effectiveness of 6 types of viable or osteoinductive bone graft material in obtaining a solid posterior spinal fusion (PSF) for single level anterior/posterior lumbar spinal fusion. The bone grafts were IBG, BMP, autogenous stem cells (MSC) from concentrated bone marrow aspirate (BMA), allograft MSC from bone marrow, adipose tissue, or amniotic fluid, combined with inert cancellous allograft (Allo). STUDY DESIGN/SETTING: Prospective, single-blinded randomized study of 6 cohorts and inert historical control. PATIENT SAMPLE: Elective anterior-posterior lumbar spinal fusion of 175 patients. OUTCOME MEASURES: Assessments included pre and postoperative back and leg pain (VAS) scores, pain drawing, disability (ODI) scores, pain medication usage, and 1-year postoperative thin-cut CT scans (read by blinded radiologists). METHODS: Patients who were surgical candidates for a 1-level anterior/posterior lumbar fusion were randomized to 1 of 6 types of posterior bone graft alternatives: IBG, BMP, BMA, allograft MSC derived from bone marrow combined with morcelized Allo (cAlloBone), adipose derived MSC combined with morcelized Allo (cAlloFat), or amnion derived MSC combined with morcelized Allo (cAlloAm). Historical Allo patients served as a negative control group. Each group (n 27) had prospective outcomes and were followed for a minimum of 2 years. Fusion rate and outcomes were compared and referenced to Allo group. RESULTS: All but 5 patients had a solid ASF. The posterior fusion rates were 98% for IBG, 94% for BMP, 85% for BMA, 67% for cAlloBone, 64% for cAlloFat, 62% for cAlloAm, and 50% for Allo. Outcomes were significantly improved for all measures for all groups and there was no difference between groups except cAlloFat had slightly greater improvement in back pain in the 7-12 month follow-up period. BMP was the most expensive graft material; cellular allografts had a high-cost relative to fusion rate. CONCLUSIONS: For single level ASF/PSF, the PSF fusion rate was significantly greater for IBG and BMP followed by BMA. Various allograft MSC bone graft options resulted in lower fusion rates but may be greater than Allo. Outcomes were uniformly improved regardless of the type of graft used or the fusion status of the posterior fusion as long as the interbody fusion was solid. If bone graft cost savings is a consideration for PSF, then IBG has the greatest radiographic value, and Allo the greatest clinical value as long as the anterior interbody fusion is solid.

Humans↗

PubMed1985

Hyponatremia after spinal fusion caused by inappropriate secretion of antidiuretic hormone (SIADH).

The Syndrome of Inappropriate Secretion of Antidiuretic Hormone (SIADH) was found to occur in at least 5% of patients recovering from a spinal fusion operation. A retrospective review was undertaken for all patients who had had a spinal fusion in 1981. The author applied strict criteria for the diagnosis of SIADH and found that at least eight of 161 patients suffered this complication. A factor analysis revealed that SIADH was most likely to develop in patients with large spinal deformities and greater than usual intraoperative blood loss. There was no correlation with age, sex, type of fusion, or cause of spinal deformity. The diagnosis, treatment, and pathogenesis of SIADH suggest that an extensive spinal fusion operation is a previously unrecognized predisposing condition.

Adolescent↗

PubMedDate not supplied

Adult idiopathic scoliosis treated by posterior spinal fusion and Harrington instrumentation.

Ninety-one patients with idiopathic scoliosis, who underwent posterior spinal fusion and instrumentation from January 1977 to December 1982, were reviewed. All patients were 20 years or older at the time of surgery and none had undergone a prior surgical procedure. Indications for surgery included pain, progressive deformity, and pulmonary symptoms. All patients had a posterior spinal fusion with Harrington instrumentation and autogenous iliac bone graft, with the addition of segmental wiring in only eight. No patient had an anterior fusion or fusion to the sacrum. Follow-up averaged 3.5 years (range: 2-7 years). The average correction at the time of surgery was 38%, and 32% at the time of last follow-up. Seventy-nine percent of the patients reported complete relief of the symptom(s) for which they had surgery. There were 34 complications in 30 (33%) patients. Pseudarthrosis occurred in 14 (15%), requiring 15 additional procedures to achieve a solid arthrodesis. Urinary tract infection occurred in 8 (9%) patients and Harrington hook dislodgement in 5 (5%). One patient sustained a partial paraparesis with recovery to a minimal deficit. No deaths occurred. Although largely successful, posterior fusion with Harrington instrumentation for adult scoliosis has a significant incidence of pseudarthrosis and instrumentation problems.

Adult↗

PubMed2000

Unilateral versus bilateral pedicle screw fixation in lumbar spinal fusion.

STUDY DESIGN: A prospective study of 87 patients who underwent unilateral or bilateral pedicle screw fixation. OBJECTIVES: To determine whether unilateral pedicle screw fixation is comparable with bilateral fixation in one- or two-segment lumbar spinal fusion. SUMMARY OF BACKGROUND DATA: Clinical results for unilateral variable screw placement instrumentation in isolated L4-L5 fusion have been reported to be as good as those for bilateral instrumentation. However, unilateral instrumentation may not be recommended for multilevel fusion. METHODS: Eighty-seven patients were assigned to either unilateral (n = 47) or bilateral (n = 40) pedicle screw instrumentation groups. Two kinds of pedicle screw system (Moss Miami, DePuy, Warsaw, IN, and Steffee VSP, AcroMed, Cleveland, OH) were used. Operating time, blood loss, duration of hospital stay, clinical outcomes, fusion rates, complication rates, and medical expenses were studied and tested with independent sample t test and chi2 test. RESULTS: There were no significant differences between the two groups in blood loss, clinically satisfactory results, fusion rate, and complication rate. There were significant differences in duration of operating time, duration of hospital stay, and medical expenses. The number of fusion segments or kinds of instrumentation did not affect the fusion rate or clinical outcomes. CONCLUSIONS: Unilateral pedicle screw fixation was as effective as bilateral pedicle screw fixation in lumbar spinal fusion independent of the number of fusion segments (one or two segments) or pedicle screw systems. Based on the results of this study, unilateral fixation could be used in two-segment lumbar spinal fusion.

Adult↗

PubMed2005

Lumbar spinal fusion patients' demands to the primary health sector: evaluation of three rehabilitation protocols. A prospective randomized study.

Very few studies have investigated the effects or costs of rehabilitation regimens following lumbar spinal fusion. The effectiveness of in-hospital rehabilitation regimens has substantial impact on patients' demands in the primary health care sector. The aim of this study was to investigate patient-articulated demands to the primary health care sector following lumbar spinal fusion and three different in-hospital rehabilitation regimens in a prospective, randomized study with a 2-year follow-up. Ninety patients were randomized 3 months post lumbar spinal fusion to either a 'video' group (one-time oral instruction by a physiotherapist and patients were then issued a video for home exercise), or a 'café' group (video regimen with the addition of three café meetings with other fusion-operated patients) or a 'training' group (exercise therapy; physiotherapist-guided; two times a week for 8 weeks). Register data of service utilization in the primary health care sector were collected from the time of randomization through 24 months postsurgery. Costs of in-hospital protocols were estimated and the service utilization in the primary health care sector and its cost were analyzed. A significant difference (P=0.023) in number of contacts was found among groups at 2-year follow-up. Within the periods of 3-6 months and 7-12 months postoperatively, the experimental groups required less than half the amount of care within the primary health care sector as compared to the video group (P=0.001 and P=0.008). The incremental costs of the café regimen respectively, the training regimen were compensated by cost savings in the primary health care sector, at ratios of 4.70 (95% CI 4.64; 4.77) and 1.70 (95% CI 1.68; 1.72). This study concludes that a low-cost biopsychosocial rehabilitation regimen significantly reduces service utilization in the primary health care sector as compared to the usual regimen and a training exercise regimen. The results stress the importance of a cognitive element of coping in a rehabilitation program.

Activities of Daily Living↗

PubMed2004

Bone tissue engineering and spinal fusion: the potential of hybrid constructs by combining osteoprogenitor cells and scaffolds.

In this paper, we discuss the current knowledge and achievements on bone tissue engineering with regard to spinal fusion and highlight the technique that employs hybrid constructs of porous scaffolds with bone marrow stromal cells. These hybrid constructs potentially function in a way comparable to the present golden standard, the autologous bone graft, which comprises besides many other factors, a construct of an optimal biological scaffold with osteoprogenitor cells. However, little is known about the role of the cells in autologous grafts, and especially survival of these cells is questionable. Therefore, more research will be needed to establish a level of functioning of hybrid constructs to equal the autologous bone graft. Spinal fusion models are relevant because of the increasing demand for graft material related to this procedure. Furthermore, they offer a very challenging environment to further investigate the technique. Anterior and posterolateral animal models of spinal fusion are discussed together with recommendations on design and assessment of outcome parameters.

Animals↗

PubMed2006

A comparison of autologous and homologous transfusions in spinal fusion.

Autologous transfusion has been used to overcome adverse effects of homologous transfusion. Clinical studies evaluating general orthopaedic postoperative results have been designed to compare these transfusion methods. However, few studies have evaluated postoperative results in spinal fusion surgeries, which have larger blood loss volumes. The purpose of this study is to determine if there are differences in postoperative infection and clinical results of spinal fusion with autologous, as compared to homologous, blood transfusion. A total of 62 patients who underwent instrumented spinal fusion and received autologous (n = 30) or homologous (n = 32) transfusions were reviewed. Information on gender, age, preoperative and 3-day postoperative hematologic features, total transfused units, segmental estimated blood loss, transfused units, and surgery time were collected. In addition, postoperative infection data on wound infection, pneumonia, urinary tract infection, cellulitis, and viral disease, incidence and duration of fever, as well as clinical results, fusion rates, and patient feedback were collected. No differences in postoperative infection and clinical results were found between the two types of transfusions; however, homologous transfusion was associated with an increased number of total units transfused, longer duration of fever, and decreased patient satisfaction regarding the transfusion.

Adult↗

PubMed2004

Absorbable self-reinforced polylactide (SR-PLLA) rods vs rigid rods (K-wire) in spinal fusion: an experimental study in rabbits.

Several clinical and experimental reports have evaluated the spinal application of bioabsorbable material for plating the anterior lumbar and cervical spine, and in anterior and posterior lumbar interbody spinal fusion. Nevertheless, the use of these materials in posterolateral interlaminar fusion has yet to be elucidated in the literature. The effects of bioabsorbable self-reinforced polylactide rod (SR-PLLA) implantation, rigid fixation (K-wire) and non-implantation with posterior interlaminar fusion were compared using a rabbit model. Twenty-four mature domestic rabbits were divided into three groups. Eight received implantation with SR-PLLA, eight with K-wire, and eight were fused without instrumentation. The animals were killed at 12 weeks and evaluated by posteroanterior radiography, manual palpation and histological examination for the presence of fusion. Successful fusion was achieved in all of the animals in both implanted groups (SR-PLLA and K-wire), whereas solid fusion was not detected in any of the specimens in the non-implanted group. Computed tomography (CT) scans were used to detect fusion mass volume. The fusion mass in the SR-PLLA implanted group had a mean volume of 1,196 mm3 +/- 167 mm3 vs 1,061 mm3 +/- 181 mm3 for the K-wire implanted group (not significant) and 711 mm3 +/- 407 mm3 (p<0.05) for the non-implanted group. The results of this study suggest that the stabilization properties of both SR-PLLA rods and K-wire seem to be sufficient for spinal fusion, but using SR-PLLA is especially advantageous, since they do not require a removal operation and do not interfere with magnetic resonance imaging (MRI).

Absorbable Implants↗

PubMed2002

Bioactive glass as bone-graft substitute for posterior spinal fusion in rabbit.

Bioactive glass S53P4 and autogenous bone were studied as bone graft materials for spinal fusion in a rabbit model. Sixteen rabbits underwent surgery by a dorsal approach. A bioactive glass, a combination of bioactive glass and autogenous bone (70/30 vol%), and autogenous bone were implanted at two thoracolumbar vertebraes for 4 and 12 weeks. The volume, consolidation to vertebrae, and fusion of the graft material were evaluated with plain-film radiology, computed tomography (CT) and bone-mineral density measurements, and compared with histomorphometrical measurements. Radiological consolidation by CT of bone graft to underlying vertebrae at 12 weeks was observable in all groups. This was histologically confirmed as bone was growing from the vertebrae into the graft material. Radiologic fusion of vertebraes was, at 12 weeks, observable in all groups in 50--75% of the cases. The radiologic fusion seen at the CT scans could, however, not be confirmed by histology in any of the three groups. Significant differences for graft material and observation period with the use of bone-mineral density measurements (Hounsfield units) were also observable, with the highest measured values for the bioactive glass group and the lowest for the autogenous bone group. The results indicate that bioactive glass have potential as bone-graft material in spinal fusion. The reliability of radiologic evaluation methods in spinal surgery using bone substitutes is also questioned and discussed.

Animals↗

PubMed2005

Structures at risk following anterior instrumented spinal fusion for thoracic adolescent idiopathic scoliosis.

OBJECTIVES: With the increasing popularity of anterior instrumented spinal fusion for adolescent idiopathic scoliosis, there has also been a rising concern over the proximity of the descending aorta to the screw tips and the possibility of vessel wall erosion over time. This computed tomography (CT) study attempts to define the relative position of the thoracic aorta and other vital structures to the spine (preoperatively) and to the projected instrumentation (postoperatively) by level and curve magnitude in deformity patients. METHODS: Twenty consecutive patients (17 female, 3 male) with an average age of 14.5 years (range 12.4-18.5 years) and a right main thoracic/Lenke 1 curve (average 55.2 degrees , range 50-66 degrees ) underwent preoperative and postoperative CT scanning as part of their planned open anterior spinal fusion with instrumentation. All images were analyzed for proximity (distance from the midvertebral body) and position to (as defined relative to the center of the vertebral body in the axial plane) the spine preoperatively and the projecting screw tip postoperatively. As a control, 10 age-matched nondeformity thoracic CT scans were analyzed to assess the relative position of the thoracic aorta to the vertebral bodies by level. Preoperative and postoperative plain radiographs were also analyzed for curve magnitude, correction, and fusion levels to assess the possible effect of these variables on the various thoracic structures. RESULTS: The postoperative curve magnitude averaged 26.9 degrees (range 17-40 degrees ; 51% correction) using 151 screws (7.5 screws/patient) and an average follow-up of 4.1 years (range 3.2-7.0 years). Screw-to-spinal-canal distance averaged 5.3 mm (range 3.5-8.2 mm) at an average of +4.5 degrees (range -11 degrees to +15 degrees ) from the coronal axis. Screw tip extrusion (distance beyond the far cortex) averaged 2.8 mm (0-5 mm). The trachea, azygous vein, esophagus, and lungs/pleura were not found to be at risk from screw penetration. The postoperative screw-tip-to-descending-aorta distance varied by vertebra level, with the periapical and distal screws being positioned closer to the aorta (1.6-2.4 mm) (P < 0.05). Additionally, 23 of 151(15%) screws were thought to be adjacent (</=2 mm) to the aorta. This includes 4 of 60 (7%) of the proximal screws but 6 of 40 (15%) of the periapical screws and 13 of 51 (26%) of the distal screws (P < 0.05). There were no screws compressing the aorta and no perioperative or postoperative complications. CONCLUSIONS: The course of the thoracic aorta may vary in individuals; however, in deformity patients, it generally moves from a relatively anterolateral position proximally to a posteromedial position at the apex. Distally, it moves more anteriorly. Consequently, the aorta moves closer to the screw tips both at the apex and distally, whereas the distal screws are more frequently juxtaposed to the descending aorta (P < 0.05).

Adolescent↗

PubMed2007

A comparison of commercially available demineralized bone matrix for spinal fusion.

In an effort to augment the available grafting material as well as to increase spinal fusion rates, the utilization of a demineralized bone matrix (DBM) as a graft extender or replacement is common. There are several commercially available DBM substances available for use in spinal surgery, each with different amounts of DBM containing osteoinductive proteins. Each product may have different osteoinductivity potential due to different methods of preparation, storage, and donor specifications. The purpose of this study is to prospectively compare the osteoinductive potential of three different commercially available DBM substances in an athymic rodent spinal fusion model and to discuss the reasons of the variability in osteoinductivity. A posterolateral fusion was performed in 72 mature athymic nude female rats. Three groups of 18 rats were implanted with 1 of 3 DBMs (Osteofil, Grafton, and Dynagraft). A fourth group was implanted with rodent autogenous iliac crest bone graft. The rats were sacrificed at 2, 4, 6, and 8 weeks. A dose of 0.3 cm(3) per side (0.6 cm(3)per animal) was used for each substance. Radiographs were taken at 2 weeks intervals until sacrifice. Fusion was determined by radiographs, manual palpation, and histological analysis. The Osteofil substance had the highest overall fusion rate (14/18), and the highest early 4 weeks fusion rate of (4/5). Grafton produced slightly lower fusion rates of (11/17) overall, and lower early 4 weeks fusion rate of (2/5). There was no statistically significant difference between the rate of fusion after implantation of Osteofil and Grafton. None of the sites implanted with Dynagraft fused at any time point (0/17), and there was a significantly lower fusion rate between the Dynagraft and the other two substances at the six-week-time point and for final fusion rate (P = 0.0001, Fischer's exact test). None of the autogenous iliac crest animals fused at any time point. Non-decalcified histology confirmed the presence of a pseudarthrosis or the presence of a solid fusion, and the results were highly correlated with the manual testing. Although all products claim to have significant osteoinductive capabilities, this study demonstrates that there are significant differences between some of the tested products.

Animals↗

PubMed2005

Junctional disc herniation syndrome in post spinal fusion treated with endoscopic spine surgery.

Fusions of the cervical and lumbar spine are often followed within months or several years by protrusion of discs at the adjacent level or levels. Biomechanical alterations and mobility lost at the fused levels are thought to be transferring the stress to the adjacent segments or discs, which results in accelerated degeneration of the discs and causes disc protrusion. This post-spinal fusion "junctional disc herniation syndrome" (JDHS), or the post-spinal fusion "adjacent segment disease (ASD)" can occur from 15% to 52% of post-spinal fusion, in both superior and/or inferior adjacent levels. The ways in which endoscopic minimally invasive spinal discectomy procedure can be used to treat this JDHS and preserve spinal segmental motion are discussed herein. Also, case illustrations are presented.

Adult↗

PubMed1984

Improved postoperative course following modified segmental instrumentation and posterior spinal fusion for idiopathic scoliosis.

Postoperative course following posterior spinal fusion was reviewed and compared for 31 patients who underwent Harrington distraction instrumentation and 30 patients who underwent modified segmental spinal instrumentation (SSI). The SSI patients, on average, received oral feedings 1 day earlier (p less than 0.046), walked 5 days earlier (p less than 0.001), and were discharged 5 days sooner (p less than 0.001) than patients undergoing Harrington distraction. Despite this more active postoperative course, the SSI patients did not require more analgesics or narcotics. When the hospital costs were compared, there was a savings of $2,825 for the average patient undergoing SSI.

Adolescent↗

PubMed2003

Lumbar spinal fusion with a mineralized collagen matrix and rhBMP-2 in a rabbit model.

STUDY DESIGN: A new mineralized collagen matrix combined with or without growth factor was used for the posterolateral spinal fusion in the rabbit lumbar spine. OBJECTIVES: The availability of a new osteoconductive matrix with or without recombinant osteoinductive growth factors offers a possible alternative to the use of autogenous bone for grafting indications. This study evaluated the bone-forming activity of the biomimetic matrix: nano-hydroxyapatite/collagen/polylactic acid (nHAC/PLA) combined without or with recombinant human bone morphogenetic protein-2 (rhBMP-2) in a rabbit posterolateral spinal fusion. SUMMARY OF BACKGROUND DATA: Many bone grafting materials such as titanium alloy, ceramics, and polymers were used to repair bony defects. However, each has specific disadvantaged. The permanent implantation still has possibility to be eroded in vivo, which is caused by late breakdown and abscess formation. The acidic outcome of polymer biodegradation was also negatively affected in the later-stage results of bone repair. It needed a promising material for an alternative to the use of autogenous bone for grafting indications. MATERIALS AND METHODS: Sixty-four rabbits were randomly divided into four groups: autologous iliac crest bone group (ACB), nHAC/PLA composite group (nHAC/PLA), autologous iliac crest bone mixed with nHAC/PLA composite group (ACB + nHAC/PLA), nHAC/PLA composite with recombinant human BMP-2 group (nHAC/PLA + rhBMP-2). The lumbar intertransverse process fusions were assessed by manual palpation, radiographic, histologic, and mechanical strength, and scanning electronic microscopy (SEM) in a 10-week observation. RESULTS: Optimal formulations of the ACB + nHAC/PLA and nHAC/PLA + rhBMP-2 groups were shown to perform similar to ACB in both the fusion ratio and mechanical strength in the 6 and 10 weeks after surgery. From the microstructure analysis of the samples, there was no negative effect when the compound implanted this composite with autogenous iliac crest, and there was also new bone-like tissue formation implanted this composite without combined rhBMP-2 early at the second week after surgery. CONCLUSIONS: This study shows the effective results of nHAC/PLA in rabbit posterolateral spinal fusion combined with rhBMP-2. It is an alternative method to autograft by compounding this osteoconductive matrix with growth factors.

Animals↗