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J Kenneth Burkus

Publications and source records attributed to J Kenneth Burkus.

At least 19 recordsLinked to original sources
PubMed2005

Surgical treatment of the painful motion segment: matching technology with indications.

STUDY DESIGN: Literature review of current bone graft technology and bone graft substitutes used in spinal fusion applications. OBJECTIVE: We reviewed current bone graft technologies and identified the range of bioactive properties that each possesses, such as osteoconductivity, osteoinductivity, and structural, load-bearing capabilities that can be used to either augment or replace autogenous bone graft in spinal fusions. SUMMARY OF BACKGROUND DATA: Bioactive materials are used in spinal fusion applications to encourage bone formation across an intervertebral motion segment. To be an effective replacement for autogenous bone grafts, a bioactive material must possess the properties of osteoinduction and osteoconduction. METHODS: Literature review. RESULTS: Platelet gel concentrates deliver nonspecific cytokines that influence local cells at the implantation site. Demineralized bone matrix acts as a bone graft enhancer that excludes fibrous tissue of muscle interposition in a fusion mass and is a mildly osteoinductive material. Bone morphogenetic proteins are an integral part of natural bone formation response. They function as differentiation factors that act on mesenchymal stem cells to induce bone formation. CONCLUSIONS: Patient-derived therapies such as platelet gel concentrates contain cytokines that play a role in bone formation; however, none of them is capable of inducing the entire bone formation cascade. Clinical use of these concentrates could possibly interfere with new bone formation. The use of bone marrow aspiration and concentration techniques has not been convincingly studied in spinal fusions in lower order animal or human clinical studies. Demineralized bone matrix contains small and variable amounts of naturally occurring bone morphogenetic proteins. These products can only function as bone graft extenders. Recombinant bone morphogenetic protein products contain much more highly concentrated and focused amounts of bone morphogenetic proteins, and some have been shown to be clinically effective bone graft replacements.

Back Pain↗
PubMed2005

The correlation between preoperative disc space height and clinical outcomes after anterior lumbar interbody fusion.

OBJECTIVE: To determine whether preoperative disc space height (DSH) influences the clinical outcomes of patients diagnosed with single-level symptomatic discogenic disease and treated with a stand-alone anterior lumbar interbody fusion with two tapered threaded fusion cages, we performed a retrospective analysis of 392 patients. METHODS: Preoperative radiographs were used to establish four study groups based on the patients' DSH: the tall disc group: DSH >15 mm; the intermediate tall group: DSH ranging from 10 to 15 mm; the intermediate collapsed group: DSH ranging from 5 to 10 mm; and the collapsed disc group: DSH <5 mm. RESULTS: All of the patient groups exhibited improvement in their clinical outcomes. However, patients in the collapsed disc group (DSH of <5 mm) tended to have earlier and greater improvement in Oswestry Disability Index scores, Physical Component Summary scores of the Short Form-36, and Visual Analog Scale scores for low back pain. CONCLUSION: Symptomatic disc degeneration can be readily identified with plain radiographic findings, and patients' symptoms can often be relieved predictably with a stand-alone interbody fusion procedure.

Adult↗
PubMed2005

Use of rhBMP-2 in combination with structural cortical allografts: clinical and radiographic outcomes in anterior lumbar spinal surgery.

BACKGROUND: Recombinant human bone morphogenetic protein-2 soaked into an absorbable collagen sponge (rhBMP-2/ACS) has been shown in a nonhuman primate study and in a pilot study in humans to promote new bone formation and incorporation of an allograft device when implanted in patients undergoing anterior lumbar interbody arthrodesis. However, a larger series with longer follow-up is needed to demonstrate its superiority to autogenous iliac crest bone graft. METHODS: Between 1998 and 2001, a two-part, prospective, randomized, multicenter study of 131 patients was conducted to determine the safety and efficacy of the use of rhBMP-2/ACS as a replacement for autogenous iliac crest bone graft in anterior lumbar spinal arthrodesis with threaded cortical allograft dowels. Patients were randomly assigned to a study group that received rhBMP-2/ACS or to a control group that received autograft. The clinical and radiographic outcomes were determined with use of well-established instruments and radiographic assessments. RESULTS: The patients in the study group had significantly better outcomes than the control group with regard to the average length of surgery (p < 0.001), blood loss (p < 0.001), and hospital stay (p = 0.020). Fusion rates were significantly better in the study group (p < 0.001). The average Oswestry Disability Index scores, Short-Form-36 physical component summary scores, and low-back and leg-pain scores were significantly better in the study group (p < 0.05). CONCLUSIONS: In patients undergoing anterior lumbar interbody arthrodesis with threaded allograft cortical bone dowels, rhBMP-2/ACS was an effective replacement for autogenous bone graft and eliminated the morbidity associated with graft harvesting.

Absorbable Implants↗
PubMed2005

Artificial disc.

Explore the source record for details and available documents.

Biomechanical Phenomena↗
PubMed2004

Anterior lumbar interbody fusion for the management of chronic lower back pain: current strategies and concepts.

In a retrospective analysis of two large multicenter clinical studies, 321 patients with degenerative lumbar disc disease were divided into two groups who underwent anterior lumbar interbody fusion using two threaded titanium fusion cages. To determine whether differences in surgical procedures and cage design affect anterior and posterior annular distraction and clinical outcomes, the authors evaluated the clinical and radiographic outcomes of patients treated with a stand-alone ALIF procedure. End-plate preservation techniques were associated with improved anterior and posterior disc space distraction compared with standard end-plate preparation techniques. Similarly, the use of the LT-CAGE device led to greater improvements in restoration of segmental lordosis than did the use of standard cylindric cages. Furthermore, these surgical benefits resulted in improved clinical outcomes as early as 3 months and were maintained over a 2-year follow-up period in patients with improved postoperative disc space distraction and lordosis. Placing cylindric cages in a lordotic or trapezoidal disc space can be accomplished only through asymmetric reaming of the vertebral end plates. In a lordotic disc space, the posterior portion of the disc must be reamed more than the anterior portion. This over-reaming inhibits distraction of the posterior disc space and limits restoration of neuroforaminal height. Reduced reaming and symmetric reaming of the vertebral end plates enable the surgeon to restore anatomic segmental lordosis across the disc space. The tapered cage configuration aids in maintaining segmental lordosis. Anatomic restoration of disc space contours has an impact on a patient's outcome after stand-alone anterior interbody fusion surgery.

Adult↗
PubMed2004

Segmental lumbar lordosis: manual versus computer-assisted measurement using seven different techniques.

OBJECTIVES: Obliteration of end-plate landmarks by interbody fusion has made the traditional measurement of segmental lumbar lordosis nearly impossible. Because the L4-L5 and L5-S1 levels are most likely to be subjected to fusion procedures or arthroplasty and contribute to more than half of normal lumbar lordosis, it is crucial to identify a reproducible and accurate means of measuring segmental lordosis at these levels. METHODS: Twelve spinal surgeons measured lordosis at L4-L5 and L5-S1 on 10 separate radiographs using three techniques for L4-L5 and four techniques for L5-S1. With use of identical radiographs, measurements first were made using a manual method and then were repeated with a computer-assisted method. Measurements were analyzed for both intraobserver and interobserver error. RESULTS: The individual data demonstrated an intraobserver variance of 9.56 and a standard deviation of 3.092 for computerized measurements compared with 7.742 and 2.782 for manual measurements. The interobserver variance was 4.107 with a standard deviation of 2.027 for the computerized group compared with 4.221 and 2.055 for manual measurements. When analyzed as a group to evaluate interobserver error, the pooled data yielded variance of 19.235 for the computerized group and 19.117 for the manual measurements. CONCLUSIONS: Variance calculations identified the Cobb technique and the posterior vertebral body technique as the least variable measurement techniques for the L4-L5 and L5-S1 levels, respectively; however, there was no statistical significance. In direct comparison, the manual and computer-assisted techniques were found to be statistically equivalent with similar degrees of variance. We believe that the anterior vertebral technique, which did not demonstrate a significant difference from other techniques, will prove to be the most reliable method of assessing segmental lumbar lordosis in patients before surgery, after interbody fusion, and after motion-sparing disc arthroplasty.

Artifacts↗
PubMed2004

Bone morphogenetic proteins in anterior lumbar interbody fusion: old techniques and new technologies. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004.

OBJECT: The author reports the clinical and radiographic outcomes obtained in three prospective multicenter clinical trials in which recombinant human bone morphogenetic protein-2 (rhBMP-2) was used in anterior lumbar interbody fusion (ALIF). METHODS: Stand-alone interbody fusion cages were used, and supplemental fixation was not performed as part of the study protocol. Patients were randomly assigned to one of two ALIF groups: one in which autologous iliac crest bone graft was used (control) and one in which an rhBMP-2-coated absorbable collagen sponge was placed (investigational group). In all patients who underwent rhBMP-2-augmented fusion, imaging demonstrated evidence of bone induction and early incorporation of the cortical allografts. Overall, more expedient clinical improvements and higher success rates were observed in the rhBMP-2 group. CONCLUSIONS: In these studies it was shown that rhBMP-2 is a safe and effective material for facilitating ALIF and for decreasing pain and improving clinical outcomes.

Bone Morphogenetic Proteins↗
PubMed2003

Retrograde ejaculation after anterior lumbar interbody fusion: transperitoneal versus retroperitoneal exposure.

STUDY DESIGN: In this multicenter, prospective, 2-year study, 146 male patients underwent a single-level anterior lumbar interbody fusion with a tapered threaded titanium fusion device. All the patients were advised before surgery of the risk for retrograde ejaculation. After surgery, any case of retrograde ejaculation was recorded as an adverse event, and the patient was observed up for the remainder of the study. OBJECTIVE: To determine the incidence of retrograde ejaculation in male patients treated for single-level degenerative lumbar disc disease at L4-L5 or L5-S1 with a stand-alone anterior interbody fusion using tapered, threaded titanium fusion cages. SUMMARY OF BACKGROUND DATA: The incidence of retrograde ejaculation in men after anterior lumbosacral spinal surgery has been reported to range from 0.42% to 5.9%. Various risk factors that increase the chance of retrograde ejaculation have been proposed. METHODS: In this prospective study, 146 male patients underwent an open surgical exposure of the lumbosacral junction and a single-level interbody fusion at either L4-L5 or L5-S1. Assessment of a patient's clinical outcome was based on written questionnaires at 6 weeks and then 3, 6, 12, and 24 months after surgery. Patients were questioned about adverse events at each of these assessments, and any case of retrograde ejaculation was recorded and followed. RESULTS: Retrograde ejaculation developed in 6 of the 146 men after open anterior lumbar interbody fusion surgery. Two cases (1.7%; 2/116) involved patients who underwent a retroperitoneal surgical exposure. Four cases (13.3%; 4/30) involved patients who had a transperitoneal surgical exposure. This difference is statistically significant according to Fisher's exact test (P = 0.017). At 12 months after surgery, 2 patients had resolution of their symptoms: 1 in the retroperitoneal approach group and 1 in the transperitoneal group. At the final 2-year follow-up, no changes in symptoms were reported. One patient in the retroperitoneal approach group (0.86%) and three patients in the transperitoneal group (10%) reported permanent retrograde ejaculation (P = 0.027). CONCLUSIONS: A transperitoneal approach to the lumbar spine at L4-L5 and L5-S1 has a 10 times greater chance of causing retrograde ejaculation in men than a retroperitoneal approach.

Ejaculation↗
PubMed2003

Radiographic assessment of interbody fusion using recombinant human bone morphogenetic protein type 2.

STUDY DESIGN: A prospective randomized study investigated the radiographic progress of fusion at 6, 12, and 24 months in 42 patients who underwent a single-level anterior lumbar interbody fusion using cylindrical interbody fusion cages. OBJECTIVE: To determine the patterns and rates of osteoinduction associated with the use of recombinant human bone morphogenetic protein type 2 (rhBMP-2) and an absorbable collagen sponge carrier in anterior lumbar interbody fusion with a tapered cylindrical fusion device. SUMMARY OF BACKGROUND DATA: Studies have shown that rhBMP-2 used with allograft dowels increases the rate of interbody fusion by promoting osteoinduction and enhancing incorporation of the allograft. In a small series of human patients undergoing anterior lumbar interbody fusion with a tapered cylindrical fusion cage, rhBMP-2 has been shown to promote osteoinduction and fusion. METHODS: In this prospective nonblinded study, 42 patients were randomly divided into two groups. The investigational group underwent interbody fusion using two tapered cylindrical fusion cages (LT-CAGE) and rhBMP-2 on an absorbable collagen sponge, and a control group underwent the procedure, receiving the devices and autogenous iliac crest bone graft. Plain radiographs and computed tomographic scans were used to evaluate the pattern of osteoinduction in the interbody space and the progression of fusion 6, 12, and 24 months after surgery. RESULTS: All the patients who received rhBMP-2 showed radiographic evidence of osteoinduction in the interbody cages 6 months after surgery. The density in the cages had increased an average of 142 Hounsfield units by 6 months. At 12 months, the increase had reached 228.7 Hounsfield units New bone formation occurred in the disc space outside the cages by 6 months in 18 of the patients in the investigational group (18/22; 82%). By 24 months, all the investigational patients showed new formation outside the cages. In the autograft control group, the density in the cages increased an average of 42 Hounsfield units, and 10 patients (10/20; 50%) showed evidence of bone formation outside the cages. CONCLUSIONS: The use of rhBMP-2 is a promising method for facilitating anterior intervertebral spinal fusion in patients who have undergone anterior lumbar fusion surgery.

Adolescent↗
PubMed2003

Is INFUSE bone graft superior to autograft bone? An integrated analysis of clinical trials using the LT-CAGE lumbar tapered fusion device.

Multicenter human clinical studies of patients undergoing anterior lumbar fusion have been conducted using recombinant bone morphogenetic protein or rhBMP-2 on an absorbable collagen sponge, marketed as INFUSE Bone Graft, or autograft implanted in the LT-CAGE Lumbar Tapered Fusion device. An integrated analysis of multiple clinical studies was performed using an analysis of covariance to adjust for preoperative variables in a total of 679 patients. Of these patients, 277 had their cages implanted with rhBMP-2 on an absorbable collagen sponge and 402 received autograft transferred from the iliac crest. The patients treated with rhBMP-2 had statistically superior outcomes with regard to length of surgery, blood loss, hospital stay, reoperation rate, median time to return to work, and fusion rates at 6, 12, and 24 months. Oswestry Disability Index scores and the Physical Component Scores and Pain Index of the SF-36 scale at 3, 6, 12, and 24 months showed statistically superior outcomes in the rhBMP-2 group.

Analysis of Variance↗
PubMed2002

Clinical and radiographic outcomes of anterior lumbar interbody fusion using recombinant human bone morphogenetic protein-2.

STUDY DESIGN: A prospective, nonblinded, multicenter study of outcomes in patients undergoing single-level anterior lumbar discectomy and interbody fusion with InFUSE Bone Graft. OBJECTIVE: To determine the safety and effectiveness of InFUSE Bone Graft applied to an absorbable collagen sponge in anterior lumbar interbody fusion with threaded cortical allografts. SUMMARY OF BACKGROUND DATA: In primates, InFUSE Bone Graft used with allograft dowels was shown to increase rates of interbody fusion by promoting osteoinduction and enhancing incorporation of the allograft. Recently, in a small series of human patients undergoing anterior lumbar interbody fusion with a tapered cylindrical metal fusion cage, InFUSE Bone Graft has been shown to promote osteoinduction and fusion. METHODS: Forty-six patients underwent a single-level anterior lumbar discectomy and interbody fusion at five investigational sites. They were randomly assigned to one of two groups, and the results in the investigational patients who received threaded cortical allograft dowels with InFUSE Bone Graft were compared with those in the control patients who received threaded allograft dowels with autogenous iliac crest bone graft. Patients' clinical outcomes were assessed using neurologic status, work status, and Oswestry Low Back Pain Disability, Short Form-36, and back and leg pain questionnaires. Anteroposterior, lateral, flexion-extension radiographs, and computed tomography scans were used to evaluate the progression of fusion at 6, 12, and 24 months after surgery. RESULTS: All patients who received InFUSE Bone Graft showed radiographic evidence of bony induction and early incorporation of the cortical allografts. All patients in this group had fusions at 12 months that remained fused at 24 months. At 12 and 24 months, the investigational group showed higher rates of fusion and improved neurologic status and back and leg pain when compared with the control group. There were no unanticipated adverse events related to the use of InFUSE Bone Graft. CONCLUSION: The use of InFUSE Bone Graft is a promising method of facilitating anterior intervertebral spinal fusion, decreasing pain, and improving clinical outcomes in patients who have undergone anterior lumbar fusion surgery with structural threaded cortical allograft bone dowels.

Adult↗
PubMed2002

Intervertebral fixation: clinical results with anterior cages.

Anterior lumbar interbody fusion has several clinical advantages over posterior or posterolateral lumbar fusion. Interbody fusion procedures place bone grafts within the disc space at the center of rotation of the vertebral motion segment. The intervertebral area is highly vascular, and the grafts have a wide contact area in the weight-bearing axis of the spinal motion segment. The high rates of fusion associated with the use of the threaded intervertebral fusion cages may be attributed, in part, to the following: (1) removal of the cartilagenous end plates and exposure of bleeding cancellous bony surfaces, (2) reestablishment of anatomic intradiscal height and tensioning of the annulus and ligamentous structures around the disc space, (3) use of appropriately sized implants to engage the peripheral apophysis of the vertebral end plates, and (4) use of autogenous grafts. Threaded interbody constructs provide adequate strength to ensure that no plastic deformation occurs within the maximum physiologic range. Dynamic testing of these implants also has shown that these implants are able to resist cyclic fatigue within typical normal daily physiologic loading. Stability testing has shown that when inserted anteriorly, these devices reduce intervertebral motion and increase spinal stiffness.

Humans↗
PubMed2002

Anterior lumbar interbody fusion using rhBMP-2 with tapered interbody cages.

In a multicenter, prospective, randomized, nonblinded, 2-year study, 279 patients with degenerative lumbar disc disease were randomly divided into two groups that underwent interbody fusion using two tapered threaded fusion cages. The investigational group (143 patients) received rhBMP-2 on an absorbable collagen sponge, and a control group (136 patients) received autogenous iliac crest bone graft. Plain radiographs and computed tomographic scans were used to evaluate fusion at 6, 12, and 24 months after surgery. Mean operative time (1.6 hours) and blood loss (109.8 mL) were less in the investigational rhBMP-2 group than in the autograft control group (2.0 hours and 153.1 mL). At 24 months the investigational group's fusion rate (94.5%) remained higher than that of the control group (88.7%). New bone formation occurred in all investigational patients. At all intervals, mean postoperative Oswestry, back pain, and leg pain scores and neurologic status improved in both treatment groups with similar outcomes. In the control group, eight adverse events related to the iliac crest graft harvest occurred (5.9%), and at 24 months 32% of patients reported graft site discomfort and 16% were bothered by its appearance. Lumbar fusion using rhBMP-2 and a tapered titanium fusion cage can yield a solid union and eliminate the need for harvesting iliac crest bone graft.

Adult↗