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James D Kang

Publications and source records attributed to James D Kang.

At least 19 recordsLinked to original sources
PubMed2006

Intraoperative somatosensory evoked potential monitoring during anterior cervical discectomy and fusion in nonmyelopathic patients--a review of 1,039 cases.

BACKGROUND CONTEXT: Intraoperative somatosensory evoked potential (SSEP) monitoring has been shown to reduce the incidence of new postoperative neurological deficits in scoliosis surgery. However, its usefulness during cervical spine surgery remains a subject of debate. PURPOSE: To determine the utility of intraoperative SSEP monitoring in a specific patient population (those with cervical radiculopathy in the absence of myelopathy) who underwent anterior cervical discectomy and fusion (ACDF) surgery. STUDY DESIGN: Retrospective review. PATIENT SAMPLE: A total of 1,039 nonmyelopathic patients who underwent single or multilevel ACDF surgery. The control group (462 patients) did not have intraoperative SSEP monitoring, whereas the monitored group (577 patients) had continuous intraoperative SSEP monitoring performed. OUTCOME MEASURE: A new postoperative neurological deficit. METHODS: SSEP tracings were reviewed for all 577 patients in the monitored group and all significant signal changes were noted. Medical records were reviewed for all 1,039 patients to determine if any new neurological deficits developed in the immediate postoperative period. RESULTS: None of the patients in the control group had any new postoperative neurological deficits. In the monitored group there were six instances of transient SSEP changes (1 due to suspected carotid artery compression; 5 thought to be due to transient hypotension) which resolved with the appropriate intraoperative intervention (repositioning of retractors; raising the arterial blood pressure). Upon waking up from anesthesia, one patient in the monitored group had a new neurological deficit (partial central cord syndrome) despite normal intraoperative SSEP signals. CONCLUSIONS: ACDF appears to be a safe surgical procedure with a low incidence of iatrogenic neurological injury. Transient SSEP signal changes, which improved with intraoperative interventions, were not associated with new postoperative neurological deficits. An intraoperative neurological deficit is possible despite normal SSEP signals.

Adult↗
PubMed2006

Postoperative management protocol for incidental dural tears during degenerative lumbar spine surgery: a review of 3,183 consecutive degenerative lumbar cases.

STUDY DESIGN: Retrospective review. OBJECTIVES: To review the experience of a single institution with degenerative lumbar surgery and to identify cases of incidental dural tears (DTs); and to report on the efficacy of our postoperative management protocol for DT, which relies on early mobilization. SUMMARY OF BACKGROUND DATA: DTs are a common complication of degenerative lumbar spine surgery. However, the management strategies for this complication vary from one surgeon to another. METHODS: A total of 3,183 degenerative lumbar spine cases (decompression and/or fusion) were reviewed. Cases complicated by an incidental DT were identified. Patients who required a return to the operating room for a second procedure were identified and the operative findings were reviewed. RESULTS: The incidence of DT during primary lumbar surgeries was 7.6% (153 of 2,024 cases), which compares to an incidence of 15.9% for revision cases (185 of 1,159 cases). If recognized during the index procedure, all DTs were repaired using a 4-0 silk suture. Six patients (4 primary, 2 revisions) who did not improve despite our postoperative management protocol were taken to the operating room for irrigation and debridement, repair of the defect, and placement of a subfascial drain to closed suction. All 6 patients went on to do well and did not have any further complications. CONCLUSIONS: DTs are common during degenerative lumbar spine surgery. Revision surgery is twice as likely as primary surgery to result in this complication. Our postoperative early mobilization protocol appears to be an effective and safe management strategy for treating this complication (98.2% success rate). Very few patients (6 of 338, or 1.8%) needed a reoperation.

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PubMed2006

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Aging↗
PubMed2006

Prevalence of symptoms of cervical and lumbar stenosis among participants in the Osteoporotic Fractures in Men Study.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To determine the prevalence of symptoms typical of cervical and lumbar stenosis, evaluate the relationship between lumbar and cervical symptoms, and assess the impact of these symptoms on health status. SUMMARY OF BACKGROUND DATA: Degenerative changes of the spine frequently associated with aging, may result in stenosis, a narrowing of the spinal canal. Little is known about the prevalence or health impact of symptoms associated with stenosis in older individuals. METHODS: Between March 2000 and April 2002, 5995 men aged > or = 65 years participating in the Osteoporotic Fractures in Men Study completed a self-administered questionnaire and clinical examination. Information was collected on demographics, spinal/joint health, and general health status. RESULTS: Overall, 14.4% of men had had clinically relevant neck pain during the previous year, and almost half this group (6.5%) had numbness/tingling/weakness (NTW) extending into the arm; 26.2% reported clinically relevant lower back pain, which in 12.2%, was accompanied by NTW extending into the leg. Men with spinal pain (neck or lower back) accompanied by NTW radiating into a limb had poorer health status than those with milder pain. CONCLUSIONS: Symptoms suggestive of cervical and lumbar stenosis are relatively common among this cohort of older men, and generalized spinal stenosis may occur in as many as 4%.

Adolescent↗
PubMed2006

Intraoperative somatosensory evoked potential monitoring during cervical spine corpectomy surgery: experience with 508 cases.

STUDY DESIGN: Retrospective review. OBJECTIVES: To review consecutive cases of cervical spine corpectomy surgery performed with intraoperative somatosensory-evoked potential (SSEP) monitoring. SUMMARY OF BACKGROUND DATA: There is controversy about the utility of SSEP monitoring during anterior cervical spine surgery. There is no study in the literature that has specifically evaluated the utility of SSEP monitoring for cervical spine corpectomy surgery. METHODS: Intraoperative SSEP tracings for 508 patients (average age, 55.7 years; 268 male, 240 female) who underwent anterior cervical fusion with single-level or multilevel corpectomies were reviewed. Intraoperative and postoperative records were analyzed to determine if any new neurologic deficits developed when the patients woke up from anesthesia. RESULTS: The overall incidence of a new postoperative neurologic deficit in this series of patients was 2.4% (11 with nerve root injury, 1 with quadriplegia). The incidence of significant SSEP changes was 5.3% (27 of 508 patients). The most common identifiable cause of SSEP changes was hypotension, and the most common neurologic deficit was deltoid (C5) weakness. One patient had irreversible SSEP changes, and he woke up with new-onset quadriplegia. The calculated sensitivity and specificity of intraoperative SSEP monitoring for detecting impending or resultant intraoperative iatrogenic neurologic injury were 77.1% and 100%, respectively. However, if the isolated nerve root injuries are removed from the analysis, then both the calculated sensitivity and the negative predictive values were 100%. CONCLUSIONS: Intraoperative SSEP monitoring can alert the surgeon to adverse iatrogenic intraoperative events with potential for neurologic injury. Most SSEP signal changes are reversible and do not result in a clinical deficit. Isolated nerve root injury appears to be the most common iatrogenic intraoperative injury during cervical spine corpectomy surgery.

Adult↗
PubMed2006

Biologic modification of animal models of intervertebral disc degeneration.

Intervertebral disc degeneration is a chronic process that can become manifest in clinical disorders such as idiopathic low back pain, sciatica, disc herniation, spinal stenosis, and myelopathy. The limited available treatment options (including discectomy and spinal fusion) for these and other disabling conditions that arise from intervertebral disc degeneration are highly invasive, achieve limited success, and only address acute symptoms while doing nothing to halt the process of degeneration. Although the precise pathophysiology of intervertebral disc degeneration has yet to be clearly delineated, the progressive decline in aggrecan, the primary proteoglycan of the nucleus pulposus, appears to be a final common pathway. Animal models as well as in vitro studies of the process of disc degeneration have yielded many potentially useful targets for the reversal of disc degeneration. One current research trend is the use of established animal models of disc degeneration to study the role of therapeutic modalities in reversing the process of degeneration, often with use of the delivery of genes or gene products that influence the anabolic and catabolic pathways of the disc. This article reviews the ability of gene-product delivery systems and gene therapy to alter biologic processes in animal models of disc degeneration and examines future trends in this field.

Animals↗
PubMed2005

Sacral insufficiency fractures following multilevel instrumented spinal fusion: case report.

STUDY DESIGN: Case series. OBJECTIVE: To report a series of patients in whom sacral insufficiency fractures developed following multilevel spinal fusion with instrumentation. SUMMARY OF BACKGROUND DATA: Rigid spinal fusion with instrumentation results in abnormal distribution of forces in the spine. These forces have the potential to cause failure of adjacent segments, especially in older, osteopenic individuals. Sacral insufficiency fractures following lumbar-sacral fusion may be the result of these abnormal forces. However, this complication is not well described in the literature. METHODS: Three patients who sustained sacral fractures after instrumented lumbar-sacral fusion performed for degenerative disease of the spine are discussed. History, physical examination findings, and radiographic features are presented, along with a brief review of the pertinent literature. RESULTS: All 3 patients in our series started complaining of new-onset buttock pain a few weeks after their operative procedure. Radiographic examination revealed that they had transverse sacral fractures just below the fusion instrumentation. Nonoperative, conservative treatment was performed. At final follow-up, the fractures had healed completely and the patients' complaints had resolved. CONCLUSION: Patients who complain of new-onset buttock pain following multilevel lumbar-sacral fusion with instrumentation should be evaluated for sacral insufficiency fractures, especially if they have been sitting for prolonged periods. Conservative treatment seems to be sufficient.

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PubMed2005

The adeno associated viral vector as a strategy for intradiscal gene transfer in immune competent and pre-exposed rabbits.

STUDY DESIGN: Experimental animal study. OBJECTIVES: This study evaluates the in vitro and in vivo transduction efficacy and transgene expression in immune competent and pre-exposed rabbits. SUMMARY OF BACKGROUND DATA: Degenerative disc disease (DDD) continues to pose a substantial clinical problem. Therapeutic options such as an interbody fusion are highly invasive and result in the loss of the intervertebral disc. In addition, interbody fusion puts the adjacent discs at an even higher risk for disc degeneration. A novel approach to slow DDD is to introduce high levels of growth factors into the degenerating disc by delivering the gene coding for the appropriate growth factor. The most efficient technique to do so to date uses viral vectors. However, viral vectors may be problematic because of their immunogenicity. The adeno-associated virus (AAV) viral vector is known to be less immunogenic than commonly used adenoviral vectors. METHODS: Human nucleus pulposus cells were transduced in vitro. Twenty-four Rabbits were injected with AAV viral vectors carrying different marker genes. Transgene expression and the humoral/cellular immune response to the vector was evaluated. RESULTS: We could show that the AAV viral vector transduces human as well as rabbit nucleus pulposus cells in vitro and in vivo. There is a significant humoral immune response against the AAV vector that decreases transgene expression over 10-fold in preimmunized animals. CONCLUSIONS: AAV is a valuable new vector to achieve transgene expression in the intervertebral disc. In preimmunized animals, its use needs to be further evaluated because of the significant reduction in transgene expression.

Animals↗
PubMed2005

A slowly progressive and reproducible animal model of intervertebral disc degeneration characterized by MRI, X-ray, and histology.

STUDY DESIGN: The progression of intervertebral disc degeneration following anterolateral "stab" of adult rabbit lumbar discs by 16-gauge hypodermic needle to a limited (5-mm) depth was studied for up to 24 weeks using magnetic resonance imaging, radiograph, and histologic outcome measures. OBJECTIVES: To develop a slowly progressive, reproducible rabbit model of intervertebral disc degeneration suitable for studying pathogenesis and pathophysiology of intervertebral disc degeneration and testing safety and efficacy of novel approaches to the treatment of intervertebral disc degeneration (e.g., growth factors, gene therapy, cell therapy, and tissue engineering). SUMMARY OF BACKGROUND DATA: Numerous animal models of intervertebral disc degeneration have been proposed in the literature, each with attendant advantages and disadvantages. The classic "stab model," involving full-thickness stab of anterior anulus fibrosus of adult rabbit lumbar discs by a number 11 scalpel blade, appears to produce changes in certain biochemical and histologic outcome measures that are similar to changes seen in human intervertebral disc degeneration. However, the immediate herniation of nucleus pulposus on full-thickness stab renders this model less suitable for 1) studying effects of less precipitous changes in nucleus pulposus and anulus fibrosus that may be important in the onset and progression of intervertebral disc degeneration and 2) testing novel therapeutic approaches that target the processes of early intervertebral disc degeneration. METHODS: The L2-L3, L3-L4, and L4-L5 lumbar intervertebral discs of 18 skeletally mature female New Zealand White rabbits were stabbed by 16-gauge hypodermic needle to a depth of 5 mm in the left anterolateral anulus fibrosus. Serial magnetic resonance imaging scans of the stabbed discs and intact L1-L2 and L5-L6 control discs were performed at 3, 6, 12, and 24 weeks post surgery and compared with preoperative magnetic resonance images. Supplemental radiograph and histologic analyses were performed. RESULTS: The stabbed discs exhibited a progressive decrease in "magnetic resonance imaging index" (the product of nucleus pulposus area and signal intensity from T2-weighted midsagittal plane images) starting at 3 weeks post stab and continuing through 24 weeks, with no evidence of spontaneous recovery or reversal of magnetic resonance imaging changes. Radiograph findings included early osteophyte formation by 6 weeks post stab and extensive, bridging osteophytes by 24 weeks. Histologic analysis revealed progressive loss of notochordal cells from the nucleus pulposus, filling of the nucleus pulposus space with fibrocartilage, and derangement of anulus fibrosus. CONCLUSIONS: Stabbing the anterolateral anulus fibrosus of adult rabbit lumbar discs with a 16-gauge hypodermic needle to a limited (5-mm) depth results in a number of slowly progressive and reproducible magnetic resonance imaging, radiograph, and histologic changes over 24 weeks that show a similarity to changes seen in human intervertebral disc degeneration. This model would appear suitable for studying pathogenesis and pathophysiology of intervertebral disc degeneration and testing safety and efficacy of novel treatments of intervertebral disc degeneration.

Animals↗
PubMed2005

Ossification of the posterior longitudinal ligament. Results of anterior cervical decompression and arthrodesis in sixty-one North American patients.

BACKGROUND: Ossification of the posterior longitudinal ligament is commonly associated with cervical myelopathy. Surgical treatment is a matter of controversy. We report on a series of patients who were managed with anterior cervical decompression and arthrodesis for the treatment of cervical myelopathy associated with ossification of the posterior longitudinal ligament. METHODS: We retrospectively reviewed the records for all sixty-five patients who had been managed with anterior decompression and arthrodesis for the treatment of cervical ossification of the posterior longitudinal ligament and associated neurologic compression from 1982 to 2001. Sixty-one patients (thirty-nine men and twenty-two women) were followed for at least two years (or until the time of death). The average number of vertebrae resected was 2.2. The average duration of follow-up for the sixty surviving patients was four years (range, two years to fifteen years and four months). The preoperative, six-week postoperative, and final follow-up clinical status (including neurological function as assessed with the Nurick grading system) was recorded for each patient. RESULTS: Fifty-six of the sixty-one patients had neurological improvement, with an average improvement of 1.5 Nurick grades at the time of the final follow-up. Eight patients had absent dura at the time of surgery and, of these, five had development of a cerebrospinal fluid fistula. Eight patients had development of new neurological signs and/or symptoms in the upper extremity postoperatively. Eight patients required reoperation because of a painful pseudarthrosis (one patient), strut-graft dislodgment (three), cerebrospinal fluid leakage (three), or compression of a nerve root caudad to the area of the original procedure (one). One patient died as the result of cardiac arrest on the third postoperative day. Fifty-eight patients had an osseous fusion, one had an asymptomatic nonunion, and one had a symptomatic pseudarthrosis that was treated with revision surgery. CONCLUSIONS: Anterior decompression and arthrodesis is an effective way to achieve pain relief and neurological improvement in North American patients of non-Asian descent who have cervical myelopathy associated with ossification of the posterior longitudinal ligament. The risk of durocutaneous fistula, graft dislodgment, and postoperative neurological symptoms appears to be high in patients with cervical myelopathy associated with this condition.

Arthrodesis↗
PubMed2004

Gene therapy approaches for intervertebral disc degeneration.

STUDY DESIGN: Review of the literature concerning the development of gene therapy approaches for the treatment of intervertebral disc degeneration. OBJECTIVES: To provide an overview of gene therapy principles, summarize the results of completed gene therapy studies, and discuss considerations for the direction of future research. SUMMARY OF BACKGROUND DATA: Intervertebral disc degeneration is characterized by progressive loss of the proteoglycan matrix in the nucleus pulposus. Exogenous growth factors have been shown to transiently increase matrix synthesis. Gene therapy offers exciting potential to induce and sustain endogenous production of growth factors within the intervertebral disc and thus possibly alter the degenerative course. METHODS: Published and presented scientific literature was examined. RESULTS/CONCLUSIONS: Several in vitro and in vivo studies have documented the capacity of gene therapy to favorably modify the biologic functions of intervertebral disc cells with the delivery of the cDNA for various growth factors. Currently, investigators are exploring the efficacy and safety of gene therapy in animal models of degeneration. With promising initial results and an immense potential clinical impact, gene therapy approaches for treatment of intervertebral disc degeneration will continue to receive dedicated research efforts.

Animals↗
PubMed2004

Late stress fracture of a well-incorporated autologous fibula strut graft in the cervical spine: a case report.

Four-level corpectomy for cervical spondylotic myelopathy presents special challenges to successful outcomes. At our institution, where the senior author has performed over 300 multilevel corpectomies with autologous fibula reconstruction, only 11 four-level procedures have been performed. It is important to consider the length of time required for complete revascularization of these long strut grafts as well as unusual postural or gait biomechanics the patient may have. Patients with altered gait or trunk stability who require anterior surgery for cervical spondylotic myelopathy may be best served by concurrent posterior fusion. We report a case in which a patient with cervical spondylotic myelopathy and diplegic cerebral palsy developed a stress fracture in the midportion of his well-incorporated autologous fibula strut graft 1 year after it was placed following four-level corpectomy.

Adult↗
PubMed2003

Gene transfer of the catabolic inhibitor TIMP-1 increases measured proteoglycans in cells from degenerated human intervertebral discs.

STUDY DESIGN: Cells from degenerated intervertebral discs were transduced with an adenoviral vector delivering cDNA of the catabolic inhibitor, TIMP-1, and alterations in the measured proteoglycan were assessed. OBJECTIVES: To assess the potential of TIMP-1 to favorably modify the proteoglycan content of degenerated intervertebral disc cells. SUMMARY OF BACKGROUND DATA: Gene therapy with anabolic factors has resulted in increased proteoglycan synthesis in intervertebral disc cells. Biochemical analysis of degenerated discs has revealed elevated levels of the catabolic enzymes, matrix metalloproteinase, suggesting an intimate role of these factors in the degenerative process. The use of TIMP-1, an endogenous inhibitor of matrix metalloproteinase, via gene therapy may provide an additional method to alter the degenerative processes occurring in the intervertebral disc. MATERIALS AND METHODS: Degenerated intervertebral disc were isolated from eight patients undergoing elective surgical procedures. Cells were cultured in monolayer and transduced with different concentrations of either an adenoviral-tissue inhibitor of metalloproteinase-1 (Ad-TIMP-1) or adenoviral-bone morphogenic protein-2 (Ad-BMP-2) construct. Cells were cultured in a three-dimensional pellet and proteoglycan synthesis was assessed via 35S-sulfur incorporation. RESULTS: Gene delivery of TIMP-1 and BMP-2 increased measured proteoglycan synthesis at each concentration assessed. IVD cells treated with Ad-TIMP-1 demonstrated an optimal response at a multiplicity of infection (MOI) of 100. Cells treated with Ad-BMP-2 demonstrated a progressive increase in proteoglycan synthesis with increasing viral concentrations. CONCLUSIONS: Successful delivery of the anticatabolic gene, TIMP-1, results in increased measured proteoglycan in cultured degenerated disc cells. This finding supports catabolic inhibition as a promising avenue of research for the treatment of degenerative disc disease via gene therapy.

Adenoviridae↗
PubMed2003

Cement augmentation of osteoporotic compression fractures and intraoperative navigation: summary statement.

Emerging techniques and technologies in treating spinal disorders appear to be very promising. Vertebroplasty and kyphoplasty are new techniques that have been developed for treating osteoporotic vertebral compression fractures with early promising clinical results. More sophisticated and technically advanced methods of surgical navigation are also being developed as spinal surgery moves toward less invasive or minimally invasive procedures. Cost effectiveness, complication rates, and clinical efficacy need to be better defined to determine the exact role of these emerging techniques and technologies.

Bone Cements↗
PubMed2003

Gene therapy applications for intervertebral disc degeneration.

STUDY DESIGN: Review of current approaches to gene therapy as a potential treatment modality for regeneration of the degenerating intervertebral disc. OBJECTIVES: Describe recent advances in the field of gene therapy pertaining to treatment of the degenerating intervertebral disc. SUMMARY OF BACKGROUND DATA: The potential application of gene therapy to the treatment of degenerative disc disease has been an area of exciting and active research. Several in vitro studies have documented the capacity of gene therapy to favorably modify the biologic functions of the intervertebral disc cells with the delivery of the cDNA for various growth factors, whereas in vivo studies have reinforced this potential in animal models. Currently, investigators are exploring the therapeutic potential of gene delivery of the cDNA for several promising factors. METHODS: Literature review. RESULTS/CONCLUSIONS: The application of gene therapy to the treatment of the degenerating intervertebral disc holds much clinical promise and continues to expand as an area of active research. The therapeutic potential of multiple agents, as well as possible vectors, are currently being investigated with encouraging results.

Animals↗
PubMed2003

Biologic treatment for intervertebral disc degeneration: summary statement.

In past decades, the biomechanics of intervertebral disc degeneration have received much attention. More recent research efforts have focused on understanding the biology of the disc degenerative process. The ability to manipulate disc architecture and biology by direct application of growth factors or by gene therapy techniques may present an opportunity to halt or slow disc degeneration. Preliminary studies using these strategies have confirmed their ability to replenish essential disc matrix components that are known to decrease with disc degeneration.

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