Lead revision surgery for vagus nerve stimulation in epilepsy: outcomes and efficacy.

We present, to our knowledge, the first published analysis of vagus nerve stimulation (VNS) lead revisions to incorporate quality of life, clinical response, and antiepileptic drug (AED) burden in postrevision clinical outcomes. Ten patients were followed and had no postoperative complications. Seven patients had improvement in quality of life, and three experienced no change. Eight patients noted a restoration of clinical response comparable with initial VNS implantation. Seven patients reported 30-60% improvement in seizure reduction, two experienced >60%, and one noted <30%. Six patients had no change in AED burden. Vagus nerve stimulation lead revision should be considered a safe option for patients with VNS lead failure and medically intractable epilepsy.

Repair of isthmic pars interarticularis fractures: a literature review of conventional and minimally invasive techniques.

INTRODUCTION: The repair of symptomatic isthmic pars interarticularis fractures can result in excellent outcomes. A variety of operative interventions exist with conventional techniques requiring larger exposures. Recently described, less invasive techniques tend to minimize disruption of adjacent soft tissues, decrease postoperative pain, increase patient satisfaction, and improve return to work status and/or competitive sports. The present review details both conventional and minimally invasive techniques of pars interarticularis repairs. Also, the review uniquely describes the authors' technique of fluoroscopically guided direct pars screw placement with recombinant human morphogenic protein, with clinical and radiographic outcomes. EVIDENCE ACQUISITION: A PubMed database literature review and retrospective chart review were conducted, in search of patients with lumbar spondylosis treated surgically. Literature review focused on various surgical techniques in repairing pars interarticularis fractures. Retrospective chart review analyzed demographic, radiographic, as well as pre- and postoperative clinical outcomes data. EVIDENCE SYNTHESIS: Surgical technique was characterized as traditional or minimally invasive operative technique. Four major operative techniques are discussed: The Buck repair, the Scott repair, the Morscher repair, and other pedicle-screw based repairs. The Levi technique is also described, utilizing minimally invasive techniques, in full. CONCLUSIONS: Surgical treatment of isthmic pars interarticularis fractures is safe and effective. Many surgical techniques exist, however minimally invasive techniques tend to provide additional clinical benefit. Moreover, fluoroscopically guided direct pars screw placement with use of recombinant human morphogenic protein, may provide the most benefit, especially in adolescent patients with high levels of physical activity.

Use of a contoured bioresorbable plate with a hemostatic plug to control life-threatening bleeding from the superior sagittal sinus during hemispherotomy: technical note.

Profuse bleeding originating from an injured cerebral sinus can be a harrowing experience for any surgeon, particularly during an operation on a young child. Common surgical remedies include sinus ligation, primary repair, placement of a hemostatic plug, and patch or venous grafting that may require temporary stenting. In this paper the authors describe the use of a contoured bioresorbable plate to hold a hemostatic plug in place along a tear in the inferomedial portion of a relatively inaccessible part of the posterior segment of the superior sagittal sinus in an 11-kg infant undergoing hemispherotomy for epilepsy. This variation on previously described hemostatic techniques proved to be easy, effective, and ultimately lifesaving. Surgeons may find this technique useful in similar dire circumstances when previously described techniques are ineffective or impractical.

A calpain inhibitor enhances the survival of Schwann cells in vitro and after transplantation into the injured spinal cord.

Despite the diversity of cells available for transplantation into sites of spinal cord injury (SCI), and the known ability of transplanted cells to integrate into host tissue, functional improvement associated with cellular transplantation has been limited. One factor potentially limiting the efficacy of transplanted cells is poor cell survival. Recently we demonstrated rapid and early death of Schwann cells (SCs) within the first 24 h after transplantation, by both necrosis and apoptosis, which results in fewer than 20% of the cells surviving beyond 1 week. To enhance SC transplant survival, in vitro and in vivo models to rapidly screen compounds for their ability to promote SC survival are needed. The current study utilized in vitro models of apoptosis and necrosis, and based on withdrawal of serum and mitogens and the application of hydrogen peroxide, we screened several inhibitors of apoptosis and necrosis. Of the compounds tested, the calpain inhibitor MDL28170 enhanced SC survival both in vitro in response to oxidative stress induced by application of H2O2, and in vivo following delayed transplantation into the moderately contused spinal cord. The results support the use of calpain inhibitors as a promising new treatment for promoting the survival of transplanted cells. They also suggest that in vitro assays for cell survival may be useful for establishing new compounds that can then be tested in vivo for their ability to promote transplanted SC survival.

Treatment of a persistent iatrogenic cerebrospinal fluid-pleural fistula with a cadaveric dural-pleural graft.

BACKGROUND CONTEXT: A cerebrospinal fluid (CSF)-pleural fistula is a unique condition with which all spine surgeons need to be familiar, particularly those who use anterolateral approaches to the thoracic region. When direct suturing of the dural defect is not possible, techniques for indirect repair must be considered. PURPOSE: To report a novel technique for repair of a thoracic CSF-pleural fistula with a cadaveric dural-pleural graft after failure of initial treatment with Duragen (Integra, Plainsboro, NJ) and fibrin glue. STUDY DESIGN/SETTING: Case report/University of Miami/Jackson Memorial Medical Center. METHODS: The case of a 65-year-old female is presented. RESULTS: The patient represented 5 weeks after the initial operation (left-sided thoracotomy, partial T10-T11 corpectomy and removal of an intradural calcified disc) with dyspnea and severe positional headaches. Imaging of the brain revealed a subdural hematoma and magnetic resonance imaging of the thoracic region demonstrated a pseudomeningocele surrounding the postsurgical bed. She underwent a revision thoracotomy and CSF-pleural fistula repair. We addressed the dural opening indirectly by suturing a piece of cadaveric dural allograft to the thickened pleura, after Duragen and fibrin glue were placed over the dural defect. A lumbar drain and a chest tube were also placed. At 12 weeks post-op, the subdural hematoma had completely resolved and her chest X-rays demonstrated a significant decrease in the CSF-pleural collection. CONCLUSION: Anterolateral thoracic disc surgery poses a great challenge to the spine surgeon but can provide the most direct way of decompressing the spinal cord as a result of ventral pathology. Some of the most difficult aspects of dealing with a CSF leak in this area relates to 1) the relative complexity of suturing the dura directly as it is at a considerable distance from the operating surgeon; 2) the manner in which the contralateral dura slopes away and is hidden from view; and 3) the relatively negative intrathoracic pressure, which encourages the persistent flow of CSF from the intradural to the pleural cavity. We speculate that with open thoracic surgery and the creation of a large potential space with an open dural defect, this technique provided an additional barrier against the formation of a CSF-pleural fistula. Using this technique, we intentionally create a pseudomeningocele into the corpectomy defect that is contained within the confines of our dural-pleural graft.

Validation of the radiosurgery-based arteriovenous malformation score in a large linear accelerator radiosurgery experience.

OBJECT: The radiosurgery-based arteriovenous malformation (AVM) score (RBAS) is a grading system designed to predict patient outcomes after Gamma Knife surgery for AVMs. This study seeks to validate independently the predictive nature of the RBAS, not only after single treatment but for retreatment, and to assess the overall outcome regardless of number of radiosurgeries. METHODS: The authors analyzed 403 patients treated with linear accelerator (LINAC) radiosurgery for AVMs between May 1988 and June 2008. The AVM scores were determined by the following equation: AVM score = (0.1 x volume in cm(3)) + (0.02 x age in years) + (0.3 x location). The location values are as follows: frontal/temporal = 0, parietal/occipital/corpus callosum/cerebellar = 1, and basal ganglia/thalamus/brainstem = 2. RESULTS: Testing demonstrated that the RBAS correlated with excellent outcomes after single or repeat radiosurgery (p < 0.001 for both variables). One hundred sixty-two (49%) of 330 patients had excellent outcomes (obliteration without deficit) after a single treatment. Excellent outcomes were achieved in 74, 64, 50, and 11% of patients with AVM scores of < 1.0 (Group 1), between 1.0 and < 1.8 (Group 2), between 1.8 and < 2.5 (Group 3), and >or= 2.5 (Group 4), respectively. Fifty-one patients (70%) obtained radiosurgical cure and 46 (63%) achieved excellent outcomes after repeat radiosurgery. Of these, 100% achieved excellent outcomes in Group 1, 70% did so in Group 2, 47% in Group 3, and 14% in Group 4. The RBAS correlated with excellent outcomes after overall treatment (p < 0.001). Two hundred seventy-seven patients (69%) obtained AVM obliteration, and 62% achieved excellent outcomes. In Group 1, 87% achieved excellent outcomes, 75% did so in Group 2, 61% in Group 3, and 24% in Group 4. CONCLUSIONS: The RBAS is a good predictor of patient outcomes after LINAC radiosurgery.