Vikram C. Prabhu

The pathogenesis of craniopharyngiomas

ObjectiveThe objective of the study is to review the pathogenesis of craniopharyngiomas.MethodsA literature review of articles relating to the embryogenesis of the pituitary gland and sella and the pathogenesis of craniopharyngiomas was performed.ConclusionsCraniopharyngiomas are benign, epithelial neoplasms of the sella and parasellar region seen in children and adults that may arise from neoplastic transformation of ectoderm-derived epithelial cell remnants of Rathke’s pouch and the craniopharyngeal duct.

Diagnosis and management of a metastatic tumor in the atlantoaxial spine.

Study Design. A retrospective review of a prospectively maintained spine database was conducted. Objectives. To review the experience of a large multidisciplinary tertiary referral oncology center in diagnosing and managing metastatic disease of the atlantoaxial spine in the era of magnetic resonance imaging, and to establish treatment parameters. Summary of Background Data. Published literature on the topic is limited, with conflicting opinions. Although external beam radiation therapy has proven value, some clinicians support aggressive surgical management. Methods. This study included all the patients who presented over a 6-year period to Memorial Sloan-Kettering Cancer Center with metastatic disease to the atlantoaxial spine. Demographics and diagnoses were obtained. Magnetic resonance images, computed tomography scans, and plain radiographs were reviewed. At presentation, patients with normal alignment or minimal subluxation were considered for nonoperative therapy, either external beam radiation therapy or chemotherapy. Surgery was reserved for patients with significant fracture subluxations, including atlantoaxial displacement more than 5 mm or angulation exceeding 11° with displacement more than 3.5 mm. Additional operative indications were prior external beam radiation therapy administered to overlapping spinal ports, unknown primary pain, and persistent pain after nonoperative therapy. Patient outcome was evaluated for pain relief, neurologic outcomes, degree of spine involvement, and survival. Results. Symptomatic metastatic tumor involving the atlantoaxial spine was diagnosed in 33 patients. The mean age at presentation was 57 years. Histologic diagnoses varied widely. All the patients presented with severe mechanical neck pain, but no patient had myelopathy related to epidural tumor or fracture subluxation. Of these 33 patients, 25 patients initially were treated nonoperatively with either external beam radiation therapy (n = 23) or chemotherapy (n = 2), and 8 patients underwent initial operation. In this nonoperatively treated group, 23 of the 25 patients had significant pain resolution until death or last follow-up assessment. Five patients required subsequent operation: three for significant fracture subluxations and two after neoadjuvant chemotherapy. Of the fracture subluxations, two were present before external beam radiation therapy, and one was delayed from rapid tumor progression. Posterior instrumentation was performed in the 13 patients who underwent surgery. No patient required anterior decompression and stabilization. Significant pain resolution was achieved in all the surgically treated patients. Conclusions. External beam radiation therapy was used successfully to treat patients with normal alignment or minimal subluxation. Selected patients warrant immediate stabilization. Patients with persistent pain and inability to wean from a hard collar after nonoperative therapy also should be considered for surgery. Posterior stabilization provides pain relief and neurologic preservation or recovery without the need for anterior decompression.

Prophylactic antibiotics with intracranial pressure monitors and external ventricular drains: a review of the evidence

BACKGROUND The role of prophylactic antibiotics (PABs) in preventing infections associated with intracranial pressure (ICP) monitors and external ventricular drains (EVD) is not well defined. METHODS This study includes an analysis of published reports and a survey of current practices regarding the use of PABs with ICP monitors and EVDs. A computerized data search and a review of the abstracts from two major national neurosurgical meetings over the past decade yielded 85 related articles. Three independent investigators, blinded to the title, author(s), institution(s), results, and conclusions of the articles used predetermined inclusion criteria to select studies for meta-analysis. Thirty-six responses were returned from 98 questionnaires (37%) mailed to university neurosurgical programs. RESULTS Among the articles reviewed, only two studies met the predetermined inclusion criteria for the meta-analysis, and they were of insufficient size to produce statistically significant results. Among the 36 programs that responded to the survey, 26 (72%) used PABs, mainly cephalosporins (46%) and semisynthetic penicillins (38%), with ICP monitors and EVDs. Twenty-two (85%) used one drug, and 4 (15%) used two drugs. Twenty-two (61%) of the total group reported intra-institutional variation in practices among individual staff neurosurgeons. Nineteen (53%) expressed interest in a retrospective study, and 27 (75%) expressed interest in a prospective study on the role of PABs in minor neurosurgical procedures. CONCLUSION No consensus regarding the use of PABs with ICP monitors and EVDs is noted. Randomized controlled trials of sufficiently large size with appropriate blinding are needed to address this issue.

Vertebral artery pseudoaneurysm complicating posterior C1-2 transarticular screw fixation: case report

BACKGROUND Vertebral artery injury during posterior C1-2 transarticular screw fixation occurs in approximately 3% of patients and may remain asymptomatic or result in arteriovenous fistulae, occlusion, narrowing, or dissection of the vertebral artery, and lead to transient ischemic attacks, stroke, or death. CASE DESCRIPTION This is the first report of a pseudoaneurysm resulting from damage to the vertebral artery during the procedure. This 31-year-old male underwent posterior C1-2 transarticular screw fixation for unstable os odontoideum. Injury to the left vertebral artery occurred while the hole for the left screw was being drilled. Temporary control of bleeding with local pressure was followed by immediate postoperative angiography that revealed a left vertebral artery pseudoaneurysm. Although the patient remained asymptomatic, therapeutic anticoagulation was instituted 6 hours postoperatively. Increasing size of the pseudoaneurysm was noted on routine follow-up angiography 4 weeks later. Endovascular occlusion of the pseudoaneurysm and left vertebral artery, with preservation of vertebrobasilar flow through the right vertebral artery, was accomplished without neurological consequence. CONCLUSIONS Vertebral artery pseudoaneurysm complicating posterior C1-2 transarticular screw fixation may be effectively treated with endovascular approaches.

Chronic subdural hematoma complicating arachnoid cyst secondary to soccer-related head injury: case report.

OBJECTIVE AND IMPORTANCE Soccer has become a popular sport, with more than 200 million Federation International Football Association-registered soccer players worldwide and 16 million participants in the United States. The risk of sustaining a significant head injury from a strike to a soccer ball with the head is unknown, but it may be increased with the presence of an underlying congenital arachnoid cyst. CLINICAL PRESENTATION We describe the case of a 16-year-old female patient who sustained a large chronic and subacute subdural hematoma without a loss of consciousness from being struck on the head by a soccer ball. Because of the large size of the hematoma and her contralateral symptoms, surgery was performed. INTERVENTION A temporal craniotomy for evacuation of a large chronic and subacute subdural hematoma with removal and fenestration of the arachnoid cyst resulted in resolution of her symptoms. Rigid craniotomy fixation of this small operative flap should allow the patient to return to soccer participation in the future. CONCLUSION Although many may not consider soccer a contact sport, recent epidemiological data suggest that it is a common cause of sports-related concussion. In addition, as our case report demonstrates, there is a risk of significant intracranial injury and hematoma formation subsequent to a strike on the head by a soccer ball, and arachnoid cysts may contribute an additional risk of head injury.

Laparoscopic-assisted distal ventriculoperitoneal shunt placement

BACKGROUND Intraperitoneal adhesions, obesity, and distorted abdominal anatomy in shunt-dependent hydrocephalic patients are patient characteristics that increase distal ventriculoperitoneal (VP) shunt failure rates. The use of laparoscopic-aided placement of the distal VP catheter as a technique to decrease the failure rate is evaluated in these patients. METHOD Thirteen hydrocephalus patients considered to either have intra-abdominal adhesions, be obese, or have distorted abdominal anatomy underwent laparoscopic-aided distal VP catheter placement or revision. Two had shunts placed for the first time and eleven had revisions. Eight patients had revisions performed by both the standard minilaparotomy and laparoscopic methods, but at different times. The average surgical times for both techniques were looked at for these eight patients. Case illustrations are presented. RESULTS In patients who had both types of abdominal approaches, the average surgical time was 81 min for the laparoscopic-aided technique versus 116 min for the minilaparotomy procedure. The only complication related directly to the laparoscopic procedure was one wound infection. CONCLUSION In patients with intra-abdominal adhesions, obesity, or distorted abdominal anatomy, laparoscopic-aided distal shunt insertion increases the success rate by its direct visual capability and the ability to lyse abdominal adhesions and position the distal end of the catheter in a desired place.

The clinical significance and optimal timing of postoperative computed tomography following cranial surgery

OBJECT This study was conducted to evaluate the value of postoperative CT scans in determining the probability of return to the operating room (OR) and the optimal time to obtain such scans to determine the effects of surgery. METHODS Between January and December 2006 (12 months), all postoperative head CT scans obtained for 3 individual surgeons were reviewed. Scans were divided into 3 groups, which were determined by the preference of each surgeon: Group A (early scans-scheduled between 0 and 7 hours); Group B (delayed scans-scheduled between 8 and 24 hours); and Group C (urgent scans-ordered because of a new neurological deficit). The initial scans were reviewed and analyzed in 2 different fashions. The first was to analyze the efficacy of the scans in predicting return to the OR. The second was to determine the optimal time for obtaining a scan. The second analysis was a review of serial postoperative scans for expected versus unexpected findings and changes in the acuity of these findings over time. RESULTS In 251 (74%) of 338 cases, the patients had postoperative head CT scans within 24 hours of surgery. Analysis 1 determined the percent of patients returning to the OR for emergency treatment based on postoperative scans: Group A (early)-133 patients, with 0% returning to the OR; Group B (delayed)-108 patients, with 0% returning to the OR; and Group C (urgent)-10 patients, with 30% returning to the OR (p < 0.05). Analysis 2 determined the optimal timing of postoperative scans and changes in scan acuity: Group A (early scan) had an 11% incidence of change in acuity on subsequent scans. Group B (delayed scan) had a 3% incidence of change in acuity on follow-up scans (p < 0.05). CONCLUSIONS Routine postoperative scans at 0-7 hours or at 8-24 hours are not predictive of return to the OR, whereas patients with a new neurological deficit in the postoperative period have a 30% chance of emergency reoperation based on CT scans. In addition, early postoperative scans (0-7 hours) fail to predict CT changes, which might evolve over time and may influence postoperative medical management.

A history of the treatment of craniopharyngiomas

RationaleNearly 100 years have passed since the first surgical attempt to remove a craniopharyngioma was undertaken, and the management of patients with these tumors continues to both challenge and frustrate those involved with their treatment.MethodsBy constructing a historical framework from past literature on the treatment of craniopharyngioma, the authors have attempted to document the early and important events in the treatment of these tumors in order to add a historical dimension to their current treatment and to engender a more comprehensive understanding of the modern treatment of craniopharyngioma.ConclusionThe application of radiotherapeutic techniques to the management of craniopharyngioma would begin to complement the role of surgery, but debate would soon emerge as to what constituted the most appropriate management for craniopharyngioma in children.

Avoidance and management of trigeminocardiac reflex complicating awake-craniotomy

The trigeminocardiac reflex occurs from manipulation or stimulation of peripheral branches or the central component of the trigeminal nerve and consists of bradycardia, hypotension, apnea, and increased gastric motility. The efferent limb of the response is mediated by the vagus nerve. This 65-year-old Caucasian male suffered an episode of bradycardia progressing to transient asystole during the course of an awake-craniotomy procedure for tumor resection. The cardiac rhythm changes resolved with administration of intravenous atropine, removal of the precipitating stimulus, and application of topical anesthetic on the dura of the middle cranial fossa. The trigeminocardiac response may complicate the course of a craniotomy and may place an awake, unintubated patient at increased risk for morbidity. The reflex may be prevented by anesthetizing the dura innervated by the trigeminal nerve via injection or topical application of local anesthetic. If encountered, removal of the stimulus, airway protection, and administration of vagolytic medications are measures that need to be considered.

An update on the PEG-SOD study involving incompetent subjects: FDA permits an exception to informed consent requirements.

project commonly referred to as the PEG-SOD study. This study raised the question of whether the FDA and HHS requirements for informed consent are unnecessarily restrictive when applied to ER research. In a recent article published in this journal, we reported on the review and approval of the PEG-SOD study by the institutional review board (IRB) of the University of Nebraska Medical Center (UNMC).1 The protocol as described in our article is a multi-