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  • Author or Editor: David F. Kallmes x
  • Journal of Neurosurgery: Spine x
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Boby V. Maramattom, Aaron A. Cohen-Gadol, Eelco F. M. Wijdicks and David Kallmes

✓ The discovery of either a dermatomal cutaneous nevus or a spinal arteriovenous malformation (AVM) should raise the suspicion of Cobb syndrome. The Cobb syndrome is a neurocutaneous syndrome in which there are metameric cutaneous and spinal AVMs. The authors present the case of a patient with acute cervical myelopathy and subtle cutaneous hemangiomas in whom a cervical perimedullary fistula was discovered. They also acknowledge Harvey Cushing's contribution to the recognition of this syndrome.

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Jennifer S. McDonald, Michelle J. Clarke, Gregory A. Helm and David F. Kallmes

Object

The presence of a “July effect,” where the influx of new residents and fellows at teaching hospitals every July may negatively affect patient care and outcomes, is widely debated. The authors used the Nationwide Inpatient Sample (NIS) to identify all cases of spinal surgery and examine outcomes among patients who underwent surgery in July compared with those who underwent surgery in other months.

Methods

Spinal surgery hospitalizations from 2001 to 2008 were identified in the NIS by extracting relevant ICD-9 codes. Rates of in-hospital mortality, discharge to a long-term care facility, and postoperative complications were compared between admission months and between teaching and nonteaching hospitals using the Wilcoxon rank-sum test, Fisher exact test, and multivariate regression analysis.

Results

Compared with patients admitted in other months, patients who were admitted to teaching hospitals in July for spinal surgery showed a similar likelihood of in-hospital mortality (OR 0.94 [95% CI 0.78–1.11], p = 0.46), reaction to implanted device/instrumentation (OR 0.88 [95% CI 0.77–1.02], p = 0.09), and postoperative wound dehiscence (OR 1.12 [95% CI 0.94–1.33], p = 0.25). A significantly higher likelihood of discharge to a long-term care facility (OR 1.03 [95% CI 1.00–1.07], p = 0.0467) and postoperative infection (OR 1.11 [95% CI 1.05–1.17], p = 0.0341) was observed in teaching hospitals in July compared with other months; however, incidence rates were similar regardless of admission month. Higher-risk patients (Charlson score ≥ 2) admitted to teaching hospitals in July had a similar likelihood of all outcomes regardless of admission month.

Conclusions

This study of nationwide hospitalizations demonstrates that the influx of new residents and fellows in July has a negligible effect on periprocedural outcomes following spinal surgery.

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Gregory A. Helm, Tord D. Alden, Elisa J. Beres, Sarah B. Hudson, Subinoy Das, Jonathan A. Engh, Debra D. Pittman, Kelvin M. Kerns and David F. Kallmes

Object. Bone morphogenetic proteins (BMPs) have been shown to have significant osteoinductive activity in numerous in vitro and in vivo assay systems, and BMP-2 and BMP-7 are currently being evaluated in human clinical studies. In the spinal region, BMPs have been shown to promote spinal arthrodesis at a higher rate than autologous bone alone. The delivery of BMPs via direct or ex vivo gene therapy techniques is also currently being evaluated and has shown promise in several mammalian models. The present study was designed to evaluate the efficacy of the use of direct, percutaneous BMP-9 adenoviral gene therapy to promote spinal fusion in the rodent.

Methods. Each animal was injected with 7.5 × 108 pfu of a BMP-9 adenoviral vector in the lumbar paraspinal musculature and allowed to survive 16 weeks. Computerized tomography studies and histological analysis demonstrated massive bone induction at the injection sites, clearly leading to solid spinal arthrodesis, without evidence of pseudarthroses, nerve root compression, or systemic side effects.

Conclusions. The results of this study strongly support the advancement of BMP gene therapy techniques toward clinical use.

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Tord D. Alden, Debra D. Pittman, Elisa J. Beres, Gerald R. Hankins, David F. Kallmes, Benjamin M. Wisotsky, Kelvin M. Kerns and Gregory A. Helm

Object. Gene therapy has many potential applications in neurosurgery. One application involves bone morphogenetic protein-2 (BMP-2), a low-molecular-weight glycoprotein that induces bone formation in vivo. Numerous studies have demonstrated that the BMP-2 protein can enhance spinal fusion. This study was undertaken to determine whether direct injection of an adenoviral construct containing the BMP-2 gene can be used for spinal fusion.

Methods. Twelve athymic nude rats were used in this study. Recombinant, replication-defective type 5 adenovirus with the cytomegalovirus (CMV) promoter and BMP-2 gene (Ad-BMP-2) was used. A second adenovirus constructed with the CMV promoter and β-galactosidase (β-gal) gene (Ad-β-gal) was used as a control. In three groups (four rats each) 7.5 µl of virus (5 × 108 particles/µl) was injected percutaneously and paraspinally at the lumbosacral junction: Group 1 received Ad-BMP-2 bilaterally; Group 2 received Ad-BMP-2 on the right, Ad-β-gal on the left; and Group 3 received Ad-β-gal bilaterally. Computerized tomography (CT) scans of the lumbosacral spine were obtained at 3, 5, 8, and 12 weeks. At 12 weeks, the animals were killed and underwent histological inspection. Ectopic bone formation was observed both on three-dimensionally reconstructed CT scans and histological examination in all rats at sites treated with Ad-BMP-2. Histological analysis demonstrated bone at different stages of maturity adjacent to the spinous processes, laminae, and transverse processes.

Conclusions. Results of this study clearly demonstrated that it is possible to produce in vivo endochondral bone formation by using direct adenoviral construct injection into the paraspinal musculature, which suggests that gene therapy may be useful for spinal fusion in the future.