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Musacchio MJ, Lauryssen C, Davis RJ, Bae HW, Peloza JH, Guyer RD, Zigler JE, Ohnmeiss DD, Leary S. Evaluation of Decompression and Interlaminar Stabilization Compared with Decompression and Fusion for the Treatment of Lumbar Spinal Stenosis: 5-year Follow-up of a Prospective, Randomized, Controlled Trial. Int J Spine Surg 2016; 10:6. [PMID: 26913226 DOI: 10.14444/3006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION If nonoperative treatment for lumbar stenosis fails, surgery may be considered. This traditionally includes decompression often combined with fusion. Desire for less extensive surgery led to developing new techniques and implants, including an interlaminar device designed with the goal of providing segmental stability without fusion, following decompression. The purpose of this study was to investigate 5-year outcomes associated with an interlaminar device. METHODS This prospective, randomized, controlled trial was conducted at 21 centers. Patients with moderate to severe lumbar stenosis at one or two contiguous levels and up to Grade I spondylolisthesis were randomized (2:1 ratio) to decompression and interlaminar stabilization (D+ILS; n=215) using the coflex(®) Interlaminar Stabilization(®) device (Paradigm Spine, LLC) or decompression and fusion with pedicle screws (D+PS; n=107). Clinical evaluations were made preoperatively and at 6 weeks and 3, 6, 12, 18, 24, 36, 48, and 60 months postoperatively. Overall Food and Drug Administration success criteria required that a patient meet 4 criteria: 1) >15 point improvement in Oswestry Disability Index (ODI) score; 2) no reoperation, revision, removal, or supplemental fixation; 3) no major device-related complication; and 4) no epidural steroid injection after surgery. RESULTS At 5 years, 50.3% of D+ILS vs. 44% of D+PS patients (p>0.35) met the composite success criteria. Reoperation/revision rates were similar in the two groups (16.3% vs. 17.8%; p >0.90). Both groups had statistically significant improvement through 60 months in ODI scores with 80.6% of D+ILS patients and 73.2% of D+PS patients demonstrating >15 point improvement (p>0.30). VAS, SF-12, and ZCQ scores followed a similar pattern of maintained significant improvement throughout follow-up. On the SF-12 and ZCQ, D+ILS group scores were statistically significantly better during early follow-up compared to D+PS. In the D+ILS group, foraminal height, disc space height, and range of motion at the index level were maintained through 5 years. CONCLUSION Both treatment groups achieved and maintained statistically significant improvements on multiple outcome assessments throughout 5-year follow-up. On some clinical measures, there were statistically significant differences during early follow-up favoring D+ILS. At no point were there significant differences favoring D+PS. Results of this 5-year follow-up study demonstrate that decompression and interlaminar stabilization with coflex is a viable alternative to traditional decompression and fusion in the treatment of patients with moderate to severe stenosis at one or two lumbar levels. LEVEL OF EVIDENCE AND ETHICAL STATEMENTS This is a Level I study. Institutional approval was received at each of the sites participating in the trial. Each patient gave informed consent to participate in the trial.
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Jackson RJ, Davis RJ, Hoffman GA, Bae HW, Hisey MS, Kim KD, Gaede SE, Nunley PD. Subsequent surgery rates after cervical total disc replacement using a Mobi-C Cervical Disc Prosthesis versus anterior cervical discectomy and fusion: a prospective randomized clinical trial with 5-year follow-up. J Neurosurg Spine 2016; 24:734-45. [PMID: 26799118 DOI: 10.3171/2015.8.spine15219] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Cervical total disc replacement (TDR) has been shown in a number of prospective clinical studies to be a viable treatment alternative to anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic degenerative disc disease. In addition to preserving motion, evidence suggests that cervical TDR may result in a lower incidence of subsequent surgical intervention than treatment with fusion. The goal of this study was to evaluate subsequent surgery rates up to 5 years in patients treated with TDR or ACDF at 1 or 2 contiguous levels between C-3 and C-7. METHODS This was a prospective, multicenter, randomized, unblinded clinical trial. Patients with symptomatic degenerative disc disease were enrolled to receive 1- or 2-level treatment with either TDR as the investigational device or ACDF as the control treatment. There were 260 patients in the 1-level study (179 TDR and 81 ACDF patients) and 339 patients in the 2-level study (234 TDR and 105 ACDF patients). RESULTS At 5 years, the occurrence of subsequent surgical intervention was significantly higher among ACDF patients for 1-level (TDR, 4.5% [8/179]; ACDF, 17.3% [14/81]; p = 0.0012) and 2-level (TDR, 7.3% [17/234]; ACDF, 21.0% [22/105], p = 0.0007) treatment. The TDR group demonstrated significantly fewer index- and adjacent-level subsequent surgeries in both the 1- and 2-level cohorts. CONCLUSIONS Five-year results showed treatment with cervical TDR to result in a significantly lower rate of subsequent surgical intervention than treatment with ACDF for both 1 and 2 levels of treatment. Clinical trial registration no.: NCT00389597 ( clinicaltrials.gov ).
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Nunley PD, Stone MB, Hisey MS, Kim KD, Jackson RJ, Bae HW, Hoffman GA, Gaede SE, Danielson GO, Gordon C, Davis RJ, Rami B. Letter to the Editor: Response to letters regarding Mobi-C cervical artificial disc. J Neurosurg Spine 2015; 24:516-8. [PMID: 26565766 DOI: 10.3171/2015.6.spine15707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bae HW, Musacchio MJ, Lauryssen C, Maislin G, Leary S. Therapeutic Sustainability and Durability of Coflex® Interlaminar Stabilization after Decompression for Lumbar Spinal Stenosis: A Four-Year Assessment. Spine J 2015. [DOI: 10.1016/j.spinee.2015.07.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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Bae HW, Lauryssen C, Maislin G, Leary S, Musacchio MJ. Therapeutic sustainability and durability of coflex interlaminar stabilization after decompression for lumbar spinal stenosis: a four year assessment. Int J Spine Surg 2015; 9:15. [PMID: 26056630 DOI: 10.14444/2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Approved treatment modalities for the surgical management of lumbar spinal stenosis encompass a variety of direct and indirect methods of decompression, though all have varying degrees of limitations and morbidity which potentially limit the efficacy and durability of the treatment. The coflex(®) interlaminar stabilization implant (Paradigm Spine, New York, NY), examined under a United States Food and Drug Administration (US FDA) Investigational Device Exemption (IDE) clinical trial, is shown to have durable outcomes when compared to posterolateral fusion in the setting of post-decompression stabilization for stenotic patients. Other clinical and radiographic parameters, more indicative of durability, were also evaluated. The data collected from these parameters were used to expand the FDA composite clinical success (CCS) endpoint; thus, creating a more stringent Therapeutic Sustainability Endpoint (TSE). The TSE allows more precise calculation of the durability of interlaminar stabilization (ILS) when compared to the fusion control group. METHODS A retrospective analysis of data generated from a prospective, randomized, level-1 trial that was conducted at 21 US sites was carried out. Three hundred forty-four per-protocol subjects were enrolled and randomized to ILS or fusion after decompression for lumbar stenosis with up to grade 1 degenerative spondylolisthesis. Clinical, safety, and radiographic data were collected and analyzed in both groups. Four-year outcomes were assessed, and the TSE was calculated for both cohorts. The clinical and radiographic factors thought to be associated with therapeutic sustainability were added to the CCS endpoints which were used for premarket approval (PMA). RESULTS Success rate, comprised of no second intervention and an ODI improvement of ≥ 15 points, was 57.6% of ILS and 46.7% of fusion patients (p = 0.095). Adding lack of fusion in the ILS cohort and successful fusion in the fusion cohort showed a CCS of 42.7% and 33.3%, respectively. Finally, adding adjacent level success to both cohorts and maintenance of foraminal height in the coflex cohort showed a CCS of 36.6% and 25.6%, respectively. With additional follow-up to five years in the U.S. PMA study, these trends are expected to continue to show the superior therapeutic sustainability of ILS compared to posterolateral fusion after decompression for spinal stenosis. CONCLUSION There are clear differences in both therapeutic sustainability and intended clinical effect of ILS compared to posterolateral fusion with pedicle screw fixation after decompression for spinal stenosis. There are CCS differences between coflex and fusion cohorts noted at four years post-op similar to the trends revealed in the two year data used for PMA approval. When therapeutic sustainability outcomes are added to the CCS, ILS is proven to be a sustainable treatment for stabilization of the vertebral motion segment after decompression for lumbar spinal stenosis.
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Davis RJ, Nunley PD, Kim KD, Hisey MS, Jackson RJ, Bae HW, Hoffman GA, Gaede SE, Danielson GO, Gordon C, Stone MB. Two-level total disc replacement with Mobi-C cervical artificial disc versus anterior discectomy and fusion: a prospective, randomized, controlled multicenter clinical trial with 4-year follow-up results. J Neurosurg Spine 2015; 22:15-25. [PMID: 25380538 DOI: 10.3171/2014.7.spine13953] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
The purpose of this study was to evaluate the safety and effectiveness of 2-level total disc replacement (TDR) using a Mobi-C cervical artificial disc at 48 months' follow-up.
METHODS
A prospective randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc was conducted at 24 centers in the US. Three hundred thirty patients with degenerative disc disease were randomized and treated with cervical total disc replacement (225 patients) or the control treatment, anterior cervical discectomy and fusion (ACDF) (105 patients). Patients were followed up at regular intervals for 4 years after surgery.
RESULTS
At 48 months, both groups demonstrated improvement in clinical outcome measures and a comparable safety profile. Data were available for 202 TDR patients and 89 ACDF patients in calculation of the primary endpoint. TDR patients had statistically significantly greater improvement than ACDF patients for the following outcome measures compared with baseline: Neck Disability Index scores, 12-Item Short Form Health Survey Physical Component Summary scores, patient satisfaction, and overall success. ACDF patients experienced higher subsequent surgery rates and displayed a higher rate of adjacent-segment degeneration as seen on radiographs. Overall, TDR patients maintained segmental range of motion through 48 months with no device failure.
CONCLUSIONS
Four-year results from this study continue to support TDR as a safe, effective, and statistically superior alternative to ACDF for the treatment of degenerative disc disease at 2 contiguous cervical levels.
Clinical trial registration no.: NCT00389597 (clinicaltrials.gov)
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Hisey MS, Bae HW, Davis R, Gaede S, Hoffman G, Kim K, Nunley PD, Peterson D, Rashbaum R, Stokes J. Multi-center, prospective, randomized, controlled investigational device exemption clinical trial comparing Mobi-C Cervical Artificial Disc to anterior discectomy and fusion in the treatment of symptomatic degenerative disc disease in the cervical spine. Int J Spine Surg 2014; 8:14444-1007. [PMID: 25694918 PMCID: PMC4325486 DOI: 10.14444/1007] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Anterior cervical discectomy and fusion (ACDF) is the gold standard for treating symptomatic cervical disc degeneration. Cervical total disc replacements (TDRs) have emerged as an alternative for some patients. The purpose of this study was to evaluate the safety and effectiveness of a new TDR device compared with ACDF for treating single-level cervical disc degeneration. METHODS This was a prospective, randomized, controlled, multicenter Food and Drug Administration (FDA) regulated Investigational Device Exemption (IDE) study. A total of 245 patients were treated (164 TDR: 81 ACDF). The primary outcome measure was overall success based on improvement in Neck Disability Index (NDI), no subsequent surgical interventions, and no adverse events (AEs) classified as major complications. Secondary outcome measures included SF-12, visual analog scale (VAS) assessing neck and arm pain, patient satisfaction, radiographic range of motion, and adjacent level degeneration. Patients were evaluated preoperatively and postoperatively at 6 weeks, 3, 6, 12, 18, and 24 months. The hypothesis was that the TDR success rate was non-inferior to ACDF at 24 months. RESULTS Overall success rates were 73.6% for TDR and 65.3% for ACDF, confirming non-inferiority (p < 0.0025). TDR demonstrated earlier improvements with significant differences in NDI scores at 6 weeks and 3 months, and VAS neck pain and SF-12 PCS scores at 6 weeks (p<0.05). Operative level range of motion in the TDR group was maintained throughout follow-up. Radiographic evidence of inferior adjacent segment degeneration was significantly greater with ACDF at 12 and 24 months (p < 0.05). AE rates were similar. CONCLUSIONS Mobi-C TDR is a safe and effective treatment for single-level disc degeneration, producing outcomes similar to ACDF with less adjacent segment degeneration. LEVEL OF EVIDENCE Level I. CLINICAL RELEVANCE This study adds to the literature supporting cervical TDR as a viable option to ACDF in appropriately selected patients with disc degeneration.
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Schrot RJ, Mathew JS, Li Y, Beckett L, Bae HW, Kim KD. Headache relief after anterior cervical discectomy: post hoc analysis of a randomized investigational device exemption trial: clinical article. J Neurosurg Spine 2014; 21:217-22. [PMID: 24836655 DOI: 10.3171/2014.4.spine13669] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECT The authors analyzed headache relief after anterior cervical discectomy. Headache may be relieved after anterior cervical discectomy, but the mechanism is unknown. If headaches were directly referred from upper cervical pathology, more headache relief would be expected from surgery performed at higher cervical levels. If spinal kinesthetics were the mechanism, then headache relief may differ between arthroplasty and fusion. Headache relief after anterior cervical discectomy was quantified by the operated disc level and by the method of operation (arthroplasty vs arthrodesis). METHODS The authors performed a post hoc analysis of an artificial disc trial. Data on headache pain were extracted from the Neck Disability Index (NDI) questionnaire. RESULTS A total of 260 patients underwent single-level arthroplasty or arthodesis. Preoperatively, 52% reported NDI headache scores of 3 or greater, compared with only 13%-17% postoperatively. The model-based mean NDI headache score at baseline was 2.5 (95% CI 2.3-2.7) and was reduced by 1.3 points after surgery (95% CI 1.2-1.4, p < 0.001). Higher cervical levels were associated with a greater degree of preoperative headache, but there was no association with headache relief. There was no significant difference in headache relief between arthroplasty and arthrodesis. CONCLUSIONS Most patients with symptomatic cervical spondylosis have headache as a preoperative symptom (88%). Anterior cervical discectomy with both arthroplasty and arthrodesis is associated with a durable decrease in headache. Headache relief is not related to the level of operation. The mechanism for headache reduction remains unclear.
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Davis RJ, Kim KD, Hisey MS, Hoffman GA, Bae HW, Gaede SE, Rashbaum RF, Nunley PD, Peterson DL, Stokes JK. Cervical total disc replacement with the Mobi-C cervical artificial disc compared with anterior discectomy and fusion for treatment of 2-level symptomatic degenerative disc disease: a prospective, randomized, controlled multicenter clinical trial: clinical article. J Neurosurg Spine 2013; 19:532-45. [PMID: 24010901 DOI: 10.3171/2013.6.spine12527] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECT Cervical total disc replacement (TDR) is intended to treat neurological symptoms and neck pain associated with degeneration of intervertebral discs in the cervical spine. Anterior cervical discectomy and fusion (ACDF) has been the standard treatment for these indications since the procedure was first developed in the 1950s. While TDR has been shown to be a safe and effective alternative to ACDF for treatment of patients with degenerative disc disease (DDD) at a single level of the cervical spine, few studies have focused on the safety and efficacy of TDR for treatment of 2 levels of the cervical spine. The primary objective of this study was to rigorously compare the Mobi-C cervical artificial disc to ACDF for treatment of cervical DDD at 2 contiguous levels of the cervical spine. METHODS This study was a prospective, randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc conducted at 24 centers in the US. The primary clinical outcome was a composite measure of study success at 24 months. The comparative control treatment was ACDF using allograft bone and an anterior plate. A total of 330 patients were enrolled, randomized, and received study surgery. All patients were diagnosed with intractable symptomatic cervical DDD at 2 contiguous levels of the cervical spine between C-3 and C-7. Patients were randomized in a 2:1 ratio (TDR patients to ACDF patients). RESULTS A total of 225 patients received the Mobi-C TDR device and 105 patients received ACDF. At 24 months only 3.0% of patients were lost to follow-up. On average, patients in both groups showed significant improvements in Neck Disability Index (NDI) score, visual analog scale (VAS) neck pain score, and VAS arm pain score from preoperative baseline to each time point. However, the TDR patients experienced significantly greater improvement than ACDF patients in NDI score at all time points and significantly greater improvement in VAS neck pain score at 6 weeks, and at 3, 6, and 12 months postoperatively. On average, patients in the TDR group also maintained preoperative segmental range of motion at both treated segments immediately postoperatively and throughout the study period of 24 months. The reoperation rate was significantly higher in the ACDF group at 11.4% compared with 3.1% for the TDR group. Furthermore, at 24 months TDR demonstrated statistical superiority over ACDF based on overall study success rates. CONCLUSIONS The results of this study represent the first available Level I clinical evidence in support of cervical arthroplasty at 2 contiguous levels of the cervical spine using the Mobi-C cervical artificial disc. These results continue to support the use of cervical arthroplasty in general, but specifically demonstrate the advantages of 2-level arthroplasty over 2-level ACDF. Clinical trial registration no.: NCT00389597 (ClinicalTrials.gov).
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Bae HW, Zhao L, Kanim LEA, Wong P, Marshall D, Delamarter RB. Bone marrow enhances the performance of rhBMP-2 in spinal fusion: a rodent model. J Bone Joint Surg Am 2013; 95:338-47. [PMID: 23426768 DOI: 10.2106/jbjs.k.01118] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Reliable and rapid bone formation is the goal of biologics and cell-based spinal fusion technologies. While no cell-based therapy alone has been successful, recombinant human bone morphogenetic protein-2 (rhBMP-2) has been successfully used in a wide spectrum of patients undergoing a variety of spinal fusion procedures since its approval by the United States Food and Drug Administration (FDA) in 2002. However, the question remains how to improve the biologic efficiency, or osteoinductivity, of rhBMP-2 for successful application in the most challenging patients undergoing spinal fusion or to reduce the doses currently required. The present study investigated how varying the cellular environments through the addition of freshly harvested bone marrow aspirate (BMA) modulates rhBMP-2 efficiency. METHODS An L4-L5 posterolateral intertransverse process spinal fusion procedure was performed in Lewis rats. The implants were a subeffective concentration of 0.006 mg/mL of rhBMP-2/two absorbable collagen sponges (ACS) plus directly applied fresh syngeneic BMA transplants (n = 18), 0.006-mg/mL rhBMP-2/two ACS/side (n = 12), 0.006-mg/mL rhBMP-2/one ACS/side (n = 12), or BMA/one ACS/side (n = 6). Rats were killed at eight weeks and were evaluated with use of manual palpation, radiographs, and biomechanical testing. RESULTS BMA plus 0.006-mg/mL rhBMP-2/ACS significantly increased the L4-L5 fusion rate to 89% (sixteen of eighteen) compared with a base fusion rate of 33% (four of twelve) to 50% (six of twelve) for rats implanted with rhBMP-2/ACS (p < 0.05), with no difference in strength or stiffness between conditions. No fusion or bone formation was observed in the six rats that received BMA/ACS alone. CONCLUSIONS Less rhBMP-2 was needed for effect when mixed with BMA. A nearly twofold increase in the fusion rate was found when BMA was mixed with a deliberate subeffective concentration of rhBMP-2. There was no improvement in terms of fusion strength or stiffness.
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Slimack NP, Bae HW. Commentary: Therapies for osteoporosis: are they good for spinal fusion? Spine J 2013; 13:200-1. [PMID: 23452569 DOI: 10.1016/j.spinee.2012.11.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 11/20/2012] [Indexed: 02/03/2023]
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Bae HW, Strenge KB, Ashraf N, Badura JM, Peckham SM, McKay WF. Transient soft-tissue edema associated with implantation of increasing doses of rhBMP-2 on an absorbable collagen sponge in an ectopic rat model. J Bone Joint Surg Am 2012; 94:1845-52. [PMID: 23079876 DOI: 10.2106/jbjs.k.00469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Recombinant human bone morphogenetic protein-2 (rhBMP-2) is an osteoinductive protein. However, soft-tissue edema adjacent to the site of rhBMP-2 implantation has been reported. This animal study was designed to examine soft-tissue edema associated with increasing rhBMP-2 doses with implantation on an absorbable collagen sponge (ACS) and with injection directly into muscle. METHODS Thirty-six Lewis rats received intramuscular implantation of rhBMP-2 on an ACS (Part I) or intramuscular injection of rhBMP-2 solution (Part II). Part-I sites received rhBMP-2/ACS at doses of 0 μg, 30 μg (normal), 129 μg (mid), or 450 μg (high). Part-II sites received rhBMP-2/ACS or rhBMP-2 intramuscular injection at doses of 10 μg (normal) or 150 μg (mid). A previous rat model showed 10 μg to be 100% effective at inducing osseous spinal fusion. In our study, T2-weighted magnetic resonance imaging (MRI) was performed at two and seven days to assess edema volume, and statistical comparisons were carried out with analysis of variance (ANOVA). Cellular response, vascularity, and ossification were examined histologically. RESULTS Quantitative MRI demonstrated similar peri-implant edema volumes in the control (buffer on an ACS) and normal-dose rhBMP-2 groups. Higher doses resulted in increased edema volume. Edema decreased significantly from two to seven days. Similar capillary densities were observed in all rhBMP-2 groups at two days, and there was dose-dependent increased ossification at seven days. Compared with the rhBMP-2 injection, implantation of the rhBMP-2/ACS resulted in increased edema. This edematous response was transient in all groups. Minimal or no ossification occurred after the rhBMP-2 injections. CONCLUSIONS Transient peri-implant soft-tissue edema occurred in a dose-dependent manner following implantation of rhBMP-2/ACS in this rat model. The normal dose of rhBMP-2/ACS produced edema similar to that in the controls. Finally, rhBMP-2 solutions injected directly into muscle resulted in minimal soft-tissue edema.
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Pradhan BB, Turner AWL, Zatushevsky MA, Cornwall GB, Rajaee SS, Bae HW. Biomechanical analysis in a human cadaveric model of spinous process fixation with an interlaminar allograft spacer for lumbar spinal stenosis: Laboratory investigation. J Neurosurg Spine 2012; 16:585-93. [PMID: 22519928 DOI: 10.3171/2012.3.spine11631] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECT Traditional posterior pedicle screw fixation is well established as the standard for spinal stabilization following posterior or posterolateral lumbar fusion. In patients with lumbar spinal stenosis requiring segmental posterior instrumented fusion and decompression, interlaminar lumbar instrumented fusion (ILIF) is a potentially less invasive alternative with reduced morbidity and includes direct decompression assisted by an interlaminar allograft spacer stabilized by a spinous process plate. To date, there has been no biomechanical study on this technique. In the present study the biomechanical properties of the ILIF construct were evaluated using an in vitro cadaveric biomechanical analysis, and the results are presented in comparison with other posterior fixation techniques. METHODS Eight L1-5 cadaveric specimens were subjected to nondestructive multidirectional testing. After testing the intact spine, the following conditions were evaluated at L3-4: bilateral pedicle screws, bilateral laminotomy, ILIF, partial laminectomy, partial laminectomy plus unilateral pedicle screws, and partial laminectomy plus bilateral screws. Intervertebral motions were measured at the index and adjacent levels. RESULTS Bilateral pedicle screws without any destabilization provided the most rigid construct. In flexion and extension, ILIF resulted in significantly less motion than the intact spine (p < 0.05) and no significant difference from the laminectomy with bilateral pedicle screws (p = 0.76). In lateral bending, there was no statistical difference between ILIF and laminectomy with unilateral pedicle screws (p = 0.11); however, the bilateral screw constructs were more rigid (p < 0.05). Under axial rotation, ILIF was not statistically different from laminectomy with unilateral or bilateral pedicle screws or from the intact spine (p > 0.05). Intervertebral motions adjacent to ILIF were typically lower than those adjacent to laminectomy with bilateral pedicle screws. CONCLUSIONS Stability of the ILIF construct was not statistically different from bilateral pedicle screw fixation following laminectomy in the flexion and extension and axial rotation directions, while adjacent segment motions were decreased. The ILIF construct may allow surgeons to perform a minimally invasive, single-approach posterior decompression and instrumented fusion without the added morbidity of traditional pedicle screw fixation and posterolateral fusion.
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Davis TT, Bae HW, Mok JM, Rasouli A, Delamarter RB. Lumbar plexus anatomy within the psoas muscle: implications for the transpsoas lateral approach to the L4-L5 disc. J Bone Joint Surg Am 2011; 93:1482-7. [PMID: 22204003 DOI: 10.2106/jbjs.j.00962] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND The transpsoas lateral surgical approach has been advocated as an alternative to direct anterior approaches for less invasive or minimally invasive access to the spine. Postoperative thigh pain, paresthesia, and/or weakness have been described after the use of this surgical approach. The purpose of this cadaveric anatomic study is to provide a description of the lumbar plexus as it relates to the transpsoas lateral surgical approach. METHODS Dissection of the lumbar plexus was performed in eighteen cadaveric specimens. Needle markers were placed in the L2-L3, L3-L4, and L4-L5 discs in the midcoronal plane. The anatomic structures were surveyed, and the proximity of the needle to the neural structures was observed. RESULTS In thirteen of the eighteen specimens, the femoral nerve received its contributions from the L2 to L4 nerve roots and was formed at the L4-L5 disc space. In all specimens, the femoral nerve passed dorsal to or directly at the midpoint of the disc. In three specimens, the needle displaced or was immediately adjacent to the femoral nerve. The femoral nerve was found between the needle and the posterior aspect of the L4-L5 disc space in thirteen of the eighteen specimens. CONCLUSIONS Because of the proximity of the neural elements, in particular the femoral nerve, to the center of the disc space, the transpsoas lateral surgical approach to the L4-L5 disc space will likely cause intraoperative displacement of neural structures from their anatomic course during retractor dilation. Careful attention should be paid to retractor placement and dilation time during transpsoas lateral access surgery, particularly at the L4-L5 disc.
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Dawson E, Bae HW, Burkus JK, Stambough JL, Glassman SD. Recombinant human bone morphogenetic protein-2 on an absorbable collagen sponge with an osteoconductive bulking agent in posterolateral arthrodesis with instrumentation. A prospective randomized trial. J Bone Joint Surg Am 2009; 91:1604-13. [PMID: 19571082 DOI: 10.2106/jbjs.g.01157] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge has been shown to be a safe and effective replacement for iliac crest bone graft when used with a threaded fusion device in anterior lumbar interbody arthrodesis. Use of rhBMP-2 on an absorbable collagen sponge in posterolateral lumbar arthrodesis requires the addition of a bulking agent to provide resistance against compression and to serve as an osteoconductive scaffold for new bone formation. METHODS We performed a prospective, randomized, multicenter pilot study to investigate the use of rhBMP-2 on an absorbable collagen sponge combined with a ceramic-granule bulking agent as a replacement for autogenous iliac crest bone graft in single-level posterolateral lumbar arthrodesis with instrumentation. The investigational group (twenty-five patients) was treated with a 1.5 mg/mL solution of rhBMP-2 on two strips of absorbable collagen sponge (total dose of rhBMP-2, 12 mg) combined with 10 cm(3) of ceramic granules. The control group (twenty-one patients) received iliac crest bone graft. Clinical outcomes were assessed with use of well-established instruments. Radiographs were reviewed to assess consolidation of fusion. RESULTS Eighty-eight percent (twenty-two) of the twenty-five patients in the investigational group and 86% (eighteen) of the twenty-one patients in the control group were considered to have completed the twenty-four-month follow-up. At all follow-up intervals, there were significant improvements in the clinical outcome measures, including the Oswestry Disability Index (ODI) scores, Short Form-36 scores, and back and leg pain scores, in both groups. At twenty-four months, the improvement in the mean ODI score, as compared with the preoperative score, was 28.2 points in the investigational group and 23.0 points in the control group. By twenty-four months, 95% (eighteen) of nineteen patients in the investigational group compared with 70% (fourteen) of twenty in the control group had a radiographically documented fusion. The overall success rate was 81% (seventeen of twenty-one) in the investigational group and 55% (eleven of twenty) in the control group (p = 0.345). CONCLUSIONS Compared with an iliac crest bone graft, the combination of an absorbable collagen sponge soaked with rhBMP-2 and ceramic granules resulted in trends toward improvements in clinical outcomes and toward a higher rate of radiographic fusion. This combination of an osteoinductive agent with an osteoconductive matrix may be an effective replacement for autograft in single-level posterolateral lumbar arthrodeses with instrumentation.
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Brau SA, Delamarter RB, Kropf MA, Watkins RG, Williams LA, Schiffman ML, Bae HW. Access strategies for revision in anterior lumbar surgery. Spine (Phila Pa 1976) 2008; 33:1662-7. [PMID: 18594459 DOI: 10.1097/brs.0b013e31817bb970] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Sixty-two consecutive patients undergoing anterior lumbar revision surgery from February 2000 to September 2007 were evaluated for approach strategies and complications. OBJECTIVE To determine the incidence of complications in these patients and to make recommendations on future revisions based on the results obtained. SUMMARY OF BACKGROUND DATA Only 2 articles exist in the literature that address this situation and they have widely varying results in a small number of patients. This larger series may help give more certainty to the expectations for complications in patients undergoing revision anterior lumbar surgery. METHODS A concurrent database was maintained on these 62 consecutive patients. Preoperative strategies were evaluated and complications were tabulated as they occurred and later analyzed to arrive at recommendations for future similar cases. RESULTS Twenty-three patients had the same level revised and 39 patients had adjacent levels operated on. There were 3 venous injuries (4.8%), 3 arterial injuries (4.8%), and 1 ureteral injury (1.6%). All 3 arterial injuries occurred while approaching L3-L4 after L4 to S1 prior fusion or disc replacement. All 3 venous injuries and the ureteral injury occurred while approaching a previously operated level or levels. Six of these patients had the injuries repaired and the procedures completed with full recovery. One L5-S1 revision had the procedure aborted after a venous injury. There were no deaths. CONCLUSION Although the incidence of complications in revisions is much greater than for index cases, the actual percentage of venous, arterial, and ureteral complications is certainly acceptable for patients who must have this type of surgery. Only very experienced access surgeons should attempt revision surgery.
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Patel VV, Zhao L, Wong P, Pradhan BB, Bae HW, Kanim L, Delamarter RB. An in vitro and in vivo analysis of fibrin glue use to control bone morphogenetic protein diffusion and bone morphogenetic protein-stimulated bone growth. Spine J 2006; 6:397-403; discussion 404. [PMID: 16825045 DOI: 10.1016/j.spinee.2005.11.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Revised: 11/22/2005] [Accepted: 01/14/2006] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Recombinant human bone morphogenetic protein-2 (rh-BMP2) has become popular for augmenting spine fusion in the lumbar and cervical spine. Concerns exist, however, over bone morphogenetic protein (BMP)-stimulated soft-tissue swelling and bone growth stimulation in areas where bone is not desired, especially as the material "leaks" into such spaces. The most detrimental effects of such leakage might be airway compromise, while heterotopic bone formation into the spinal canal has been reported in animal and human studies. Fibrin glue has been used as a carrier of many osteoinductive materials; however, its efficacy at modulating the clinical effects of BMP are not known. The amorphous nature of fibrin glue makes it a candidate to control diffusion of BMP and possibly limit bone formation by limiting BMP diffusion to areas where such bone is not desired. PURPOSE To evaluate the use of fibrin glue to limit BMP diffusion and BMP-stimulated bone growth. STUDY DESIGN/SETTING This is an in vitro basic science study and an in vivo prospective randomized animal study. STUDY SAMPLE Eighteen Lewis rats. OUTCOME MEASURES In vitro study: Enzyme-linked immunosorbent assay measurement of rh-BMP2 concentration in saline. In vivo study: At day 60, rats were evaluated for neurologic deficits before sacrifice. Spines were harvested, and the following studies were performed: 1) manual testing for fusion and bone growth; 2) X-ray evaluation; 3) Micro-computed tomography (micro-CT) scans. METHODS In vitro study: Collagen sponges soaked with BMP at two different concentrations were incubated in saline solution with and without encapsulation by fibrin glue. Saline BMP concentrations were measured at consecutive time points. In vivo study: A rat fusion model using rh-BMP2 for fusion has been developed and tested with resultant100% fusion in over 100 rats. Lewis rats were divided into two groups and treated as follows: I: Exposure of L4-L5 transverse processes, decortication, and placement of BMP sponge in the lateral intertransverse space. II: Exposure and decortication as above and placement of fibrin glue before BMP sponge placement. RESULTS In vitro study: Peak rh-BMP2 concentrations in saline were 20% and 45% of the maximum possible for fibrin glue encapsulated sponges and controls, respectively, with a more gradual increase to peak concentration in samples encapsulated in fibrin glue. In vivo study: No rats exhibited any neurologic deficits. X-rays revealed at least partial bone formation in all rats. Manual testing of intertransverse fusion spines revealed 100% fusion in rats treated with BMP only, whereas rats treated with fibrin glue before placement of BMP sponges revealed only one possible fusion. Posterior-lateral bone formation was present on X-ray in both groups, and micro-CT imaging revealed bridging bone from transverse processes to the BMP-stimulated bone in the control groups. In spines treated with fibrin glue before rh-BMP2 placement, bone formation could still be seen within the soft tissues; however, bridging bone connecting to the transverse processes was either significantly decreased or not present. CONCLUSIONS Fibrin glue can limit rh-BMP2 diffusion. Also, because it limited bone formation at the transverse processes, it can be inferred that fibrin glue can limit bone formation when used to separate areas of desired bone formation from areas where bone formation is not desired.
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Yee AJM, Bae HW, Friess D, Roth SM, Whyne C, Robbin M, Johnstone B, Yoo JU. The use of simvastatin in rabbit posterolateral lumbar intertransverse process spine fusion. Spine J 2006; 6:391-6. [PMID: 16825044 DOI: 10.1016/j.spinee.2005.10.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Accepted: 10/05/2005] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT There has been recent enthusiasm regarding the potential positive effects of statins on bone. Statins vary in their ability to influence bone activity. Simvastatin has been shown in experimental models to stimulate bone acting growth factors and enhance bone formation. PURPOSE The potential efficacy of Simvastatin in enhancing spinal fusion was evaluated in a rabbit posterolateral intertransverse process fusion model. STUDY DESIGN/SETTING Posterior lumbar intertransverse process spinal fusion performed on New Zealand White rabbits. PATIENT/STUDY SAMPLE: 44 New Zealand White rabbits. OUTCOME MEASURES Spinal fusion as determined by manual palpation testing and fine detail radiography. Bone fusion mass volume and density as determined by CT scan imaging. METHODS Forty-four New Zealand White rabbits underwent posterolateral intertransverse process spine fusion using autogenous iliac crest bone graft. Simvastatin was administered orally in 20 animals and the serum lipid profile quantified in test and control animals. The animals were euthanized 9 weeks following index surgery and the lumbar spine was harvested. Spinal fusion was determined by manual palpation testing and fine detail radiography. The volume and density of the bone fusion mass was quantified by computed tomography. RESULTS Drug treatment for 9 weeks caused a reduction in serum lipid biochemical markers when compared with controls. The spinal fusion rate, as judged by manual palpation testing (13.0% control group, 16.6% Simvastatin group) and fine detail radiography, was not significantly different comparing treatment with control animals. Accordant with the assessment of spinal fusion, there was no statistically significant effect on the volume of the fusion mass (1,224.7+/-98.7 mm(3) in the control group and 1,075.9+/-66.3 mm(3) in the Simvastatin group), the density of bone in the lumbar spine or that in the formed fusion mass. CONCLUSIONS Systemic use of Simvastatin caused a reduction in lipid biochemical parameters in treated animals. Successful spinal fusion as judged by manual palpation testing and fine detail radiography was not significantly different in treated versus untreated animals. The bone volume density of the formed fusion mass was not significantly different in treated versus untreated animals. There did not appear to be a significant advantage or disadvantage to the use of Simvastatin rabbit posterolateral spinal fusion. The potential positive effects of statins on bone require further study.
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Bae HW, Zhao L, Kanim LEA, Wong P, Delamarter RB, Dawson EG. Intervariability and intravariability of bone morphogenetic proteins in commercially available demineralized bone matrix products. Spine (Phila Pa 1976) 2006; 31:1299-306; discussion 1307-8. [PMID: 16721289 DOI: 10.1097/01.brs.0000218581.92992.b7] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Enzyme-linked immunosorbent assay was used to detect bone morphogenetic proteins (BMPs) 2, 4, and 7 in 9 commercially available ("off the shelf") demineralized bone matrix (DBM) product formulations using 3 different manufacturer's production lots of each DBM formulation. OBJECTIVES To evaluate and compare the quantity of BMPs among several different DBM formulations (inter-product variability), as well as examine the variability of these proteins in different production lots within the same DBM formulation (intra-product variability). SUMMARY OF BACKGROUND DATA DBMs are commonly used to augment available bone graft in spinal fusion procedures. Surgeons are presented with an ever-increasing variety of commercially available human DBMs from which to choose. Yet, there is limited information on a specific DBM product's osteoinductive efficacy, potency, and constancy. METHODS There were protein extracts from each DBM sample separately dialyzed 4 times against distilled water at 4 degrees C for 48 hours. The amount of BMP-2, BMP-4, and BMP-7 was determined using enzyme-linked immunosorbent assay. RESULTS.: The concentrations of detected BMP-2 and BMP-7 were low for all DBM formulations, only nanograms of BMP were extracted from each gram of DBM (20.2-120.6 ng BMP-2/g DBM product; 54.2-226.8 ng BMP-7/g DBM). The variability of BMP concentrations among different lots of the same DBM formulation, intra-product variability, was higher than the variability of concentrations among different DBM formulations, inter-product variability (coefficient of variation range BMP-2 [16.34% to 76.01%], P < 0.01; BMP-7 [3.71% to 82.08%], P < 0.001). BMP-4 was undetectable. CONCLUSIONS The relative quantities of BMPs in DBMs are low, in the order of 1 x 10(-9) g of BMP/g of DBM. There is higher variability in concentration of BMPs among 3 different lots of the same DBM formulation than among different DBM formulations. This variability questions DBM products' reliability and, possibly, efficacy in providing consistent osteoinduction.
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Patel VV, Zhao L, Wong P, Kanim L, Bae HW, Pradhan BB, Delamarter RB. Controlling bone morphogenetic protein diffusion and bone morphogenetic protein-stimulated bone growth using fibrin glue. Spine (Phila Pa 1976) 2006; 31:1201-6. [PMID: 16688032 DOI: 10.1097/01.brs.0000217650.90861.99] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An in vitro and in vivo study. OBJECTIVE To evaluate the ability of fibrin glue to limit diffusion of recombinant human bone morphogenetic protein (rhBMP)-2 and its ability to protect spinal nerves from rhBMP-2 stimulated bone growth. SUMMARY OF BACKGROUND DATA Studies have shown bone morphogenetic protein (rhBMP-2) stimulated bone growth can encroach on the spinal canal and nerves, causing neural compression. More recently, rhBMP-2 use in the cervical spine has been associated with life-threatening swelling. Fibrin glue has been used as a biologic carrier but has not been evaluated for its ability to limit rhBMP-2. METHODS In phase 1 of the study, rhBMP-2 soaked absorbable collagen sponges (ACS) were encapsulated in fibrin glue and immediately incubated in physiologic lactated ringers solution at 38 degrees C. Samples of solution were tested for rhBMP-2 concentration. In phase 2 of the study, rats were surgically treated with laminectomy and placement of rhBMP-2/ACS versus laminectomy and placement of fibrin glue before placement of rhBMP-2/ACS. After 8 weeks, animals were euthanized and imaged using micro-computerized tomography. RESULTS The diffusion study showed a significant limitation in rhBMP-2 diffusion when encapsulated in fibrin glue. The laminectomy study revealed blockage of bone formation by fibrin glue and protection of the spinal canal. CONCLUSIONS Fibrin glue can limit the diffusion of rhBMP-2, and, thus, it can be used to help protect the spinal canal and nerve roots from rhBMP-2 stimulated bone growth.
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Pradhan BB, Bae HW, Dawson EG, Patel VV, Delamarter RB. Graft resorption with the use of bone morphogenetic protein: lessons from anterior lumbar interbody fusion using femoral ring allografts and recombinant human bone morphogenetic protein-2. Spine (Phila Pa 1976) 2006; 31:E277-84. [PMID: 16648733 DOI: 10.1097/01.brs.0000216442.12092.01] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN This is a prospective cohort study examining the results and radiographic characteristics of anterior lumbar interbody fusion (ALIF) using femoral ring allografts (FRAs) and recombinant human bone morphogenetic protein-2 (rhBMP-2). This was compared to a historical control ALIF using FRAs with autologous iliac crest bone graft (ICBG). OBJECTIVE To determine whether the use of rhBMP-2 can enhance fusion ALIF with stand-alone FRAs. SUMMARY OF BACKGROUND DATA ALIF is a well-accepted procedure in reconstructive spine surgery. Advances in spinal surgery have produced a multitude of anterior interbody implants. The rhBMP-2 has promoted fusion in patients undergoing ALIF with cages and threaded allograft dowels. The FRA still remains a traditional alternative for anterior support. However, as a stand-alone device, the FRA has fallen into disfavor because of high rates of pseudarthrosis. With the advent of rhBMP-2, the FRA may be more attractive because of its simplicity and remodeling potential. It is important to understand the implications when rhBMP-2 is used with such structural allografts. METHODS A total of 36 consecutive patients who underwent ALIF with stand-alone FRAs by a single surgeon (E.G.D.) at 1 institute were included. A cohort of 9 consecutive patients who received FRAs filled with rhBMP-2 was followed prospectively. After noticing suboptimal results, the senior author terminated this method of lumbar fusion. A total of 27 prior consecutive patients who received FRAs filled with autogenous ICBG were used for comparison. Analyzing sequential radiographs, flexion-extension radiographs, and computerized tomography with multiplanar reconstructions determined nonunions. Minimum follow-up was 24 months. RESULTS Pseudarthrosis was identified in 10 of 27 (36%) patients who underwent stand-alone ALIF with FRAs and ICBG. Nonunion rate was higher among patients who received FRAs with rhBMP-2 (i.e., 5 of 9 [56%]). Statistical significance was not established because of the early termination of the treatment group (P > 0.3). Of interest, radiographs and computerized tomography revealed early and aggressive resorption of the FRAs when used with rhBMP-2. This preceded graft fracture and even disintegration, resulting in instability and eventual nonunion. CONCLUSION The use of rhBMP-2 did not enhance the fusion rate in stand-alone ALIF with FRAs. In fact, the trend was toward a higher nonunion rate with rhBMP-2, although this was not significant with the numbers available. This result appears to be caused by the aggressive resorptive phase of allograft incorporation, which occurs before the osteoinduction phase.
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Patel VV, Andrews C, Pradhan BB, Bae HW, Kanim LEA, Kropf MA, Delamarter RB. Computed tomography assessment of the accuracy of in vivo placement of artificial discs in the lumbar spine including radiographic and clinical consequences. Spine (Phila Pa 1976) 2006; 31:948-53. [PMID: 16622387 DOI: 10.1097/01.brs.0000209252.21129.8d] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Prospective cohort study of 52 patients who had undergone artificial lumbar disc replacement. OBJECTIVES To evaluate the implantation accuracy of prosthesis positioning, subsequent facet joint changes and prosthesis migration, and the clinical consequences of implant position. SUMMARY OF BACKGROUND DATA Accuracy of spinal prosthesis implantation has not been evaluated rigorously, especially with a mini-incision approach. It is unknown if the inexact placement of a mobile device in the spine has any biomechanical, radiographic, or clinical repercussions. METHODS A total of 52 consecutive patients were treated using standard methods of disc implantation with an intervertebral prosthesis. Computed tomography scans were performed within 3 days and again at 6 to 24 months. An independent radiologist analyzed the images for prosthesis position, rotation, migration, and facet changes. Results were compared with clinical outcome, measured by the Visual Analog Scale and Oswestry Disability Index. RESULTS Deviation of the prosthesis from the center position was under 1.2 mm, and rotation off of midline was under 12 degrees. Follow-up CT scans showed no migration or facet changes. Regression analysis showed no correlation of prosthesis position with clinical outcome. CONCLUSIONS Current prosthetic disc implantation methods, with minimally invasive access techniques, are relatively accurate. Although there can be deviation of the prosthesis from ideal placement, no repercussions were attributable.
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Pradhan BB, Bae HW, Kropf MA, Patel VV, Delamarter RB. Kyphoplasty reduction of osteoporotic vertebral compression fractures: correction of local kyphosis versus overall sagittal alignment. Spine (Phila Pa 1976) 2006; 31:435-41. [PMID: 16481954 DOI: 10.1097/01.brs.0000200036.08679.1e] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A retrospective study of patients who underwent 1-3-level kyphoplasty procedures at a single institute. OBJECTIVE To examine and compare the effects of single and multilevel kyphoplasty procedures on local versus overall sagittal alignment of the spine. SUMMARY OF BACKGROUND DATA Cement augmentation has been a safe and effective method in the treatment of symptomatic vertebral compression fractures (VCFs). In addition to providing rapid pain relief, balloon tamp kyphoplasty has reduced acute fractures, allowed controlled cement placement under lower pressure, and resulted in improvement of deformity. The restoration of normal overall spinal sagittal alignment in the elderly patient with a VCF and kyphotic deformity has obvious benefits. Although significant correction of local kyphosis (fractured vertebra) has been reported in the literature, to our knowledge, there have been no reports on whether this leads to an improved overall sagittal alignment. METHODS A total of 65 consecutive patients with symptomatic VCFs who underwent 1-3-level kyphoplasty procedures were included in the study. Preoperative and postoperative radiographs were analyzed to quantify local and overall spinal sagittal alignment correction. Preoperative and postoperative vertebral heights at the fractured levels were also measured and categorized into anterior, middle, or posterior vertebral heights. RESULTS Measurements revealed that kyphoplasty reduced local kyphotic deformity at the fractured vertebra by an average of 7.3 degrees (63% of preoperative kyphosis). This result did not translate to similar correction in overall sagittal alignment. In fact, angular correction decreased to 2.4 degrees (20% of preoperative kyphosis at fractured level) when measured 1 level above and below. The angular correction further decreased to 1.5 degrees and 1.0 degrees (13% and 8% of preoperative kyphosis at fractured level), respectively, at spans of 2 and 3 levels above and below. Average height gain was highest in the middle of the vertebral body (39% increase) compared to the anterior or posterior edges (19% and 3% increases, respectively). With multilevel kyphoplasty procedures, higher angular gains were seen over more vertebrae compared to the 7.3 degrees for a single-level kyphoplasty: 7.8 degrees over 2 levels and 7.7 degrees over 3 levels for 2 and 3-level kyphoplasty procedures, respectively. Kyphoplasty was able to achieve higher angular reduction in thoracic versus lumbar fractures (8.5 vs. 6.4 degrees, P < 0.01). The angular correction was also better maintained over adjacent segments in the thoracic spine. CONCLUSION The majority of kyphosis correction by kyphoplasty is limited to the vertebral body treated. The majority of height gained after kyphoplasty occurs in the midbody. Higher correction over longer spans of the spine can be achieved with multilevel kyphoplasty procedures, in proportion to the number of levels addressed. Notwithstanding its well-published clinical efficacy, it is unrealistic to expect a 1 or 2-level kyphoplasty to improve significantly the overall sagittal alignment after VCFs.
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Delamarter RB, Bae HW, Pradhan BB. Clinical results of ProDisc-II lumbar total disc replacement: report from the United States clinical trial. Orthop Clin North Am 2005; 36:301-13. [PMID: 15950690 DOI: 10.1016/j.ocl.2005.03.004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The much-awaited clinical use of lumbar artificial discs has begun in the United States. The United States Investigational Device Exemption (US IDE) clinical trial of the ProDisc-II prosthetic disc (Synthes, Paoli, PA) was recently completed, with all indications that it meets or surpasses the test of equivalence against fusion controls. This is a review of the clinical performance of the ProDisc-II artificial disc and includes an interim report from the US IDE trial at one site.
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Yee AJM, Bae HW, Friess D, Robbin M, Johnstone B, Yoo JU. Accuracy and interobserver agreement for determinations of rabbit posterolateral spinal fusion. Spine (Phila Pa 1976) 2004; 29:1308-13. [PMID: 15187630 DOI: 10.1097/01.brs.0000127184.43765.61] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN The accuracy and interobserver agreement of fine detail radiography and computed tomography (CT) determination of spinal fusion were evaluated in an established animal spine fusion model. OBJECTIVE To determine the accuracy and interobserver agreement of radiographic determinations of spinal fusion in rabbit posterolateral spine fusion. SUMMARY OF BACKGROUND DATA The rabbit posterolateral intertransverse process spine fusion model is an established animal model for evaluating bone graft alternatives for spinal fusion. However, little is known regarding the accuracy and interobserver agreement of radiographic determinations of spondylodesis in this model. METHODS Forty-two New Zealand White rabbits underwent posterolateral spinal fusion. The animals were killed at 9 weeks and the lumbar spine harvested. Manual manipulation, fine detail radiography, and CT images were used to assess spinal fusion. RESULTS Using manual palpation testing as the standard by which to assess fusion, there was high sensitivity and negative predictive value for both radiographic methods. Positive predictive value, however, was poor (26% fine detail radiography, 61% CT scan). CT correlated better with manual palpation testing when compared with fine detail radiographs. There was substantial interobserver agreement of successful fusion using CT scan imaging (kappa = 0.63) and moderate interobserver agreement radiographs (kappa = 0.52). CONCLUSIONS Both radiographic techniques used in the study recorded high sensitivity and negative predictive value. However, positive predictive value was poor, especially with fine detail radiographs. Nevertheless, CT with reformatted images did appear to be superior to fine detail radiographs in accurately identifying nonunions in this animal model.
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