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Venkatesh S. Madhugiri, Mario K. C. Teo, Joli Vavao, Teresa Bell-Stephens and Gary K. Steinberg

OBJECTIVE

Brainstem arteriovenous malformations (AVMs) are rare lesions that are difficult to diagnose and treat. They are often more aggressive in their behavior when compared with their supratentorial counterparts. The consequence of a brainstem hemorrhage is often devastating, and many patients are in poor neurological status at presentation. The authors examine the factors associated with angiographically confirmed cure and those affecting management outcomes for these complex lesions.

METHODS

This was a retrospective analysis of data gathered from the prospectively maintained Stanford AVM database. Lesions were grouped based on their location in the brainstem (medulla, pons, or midbrain) and the quadrant they occupied. Angiographic cure was dichotomized as completely obliterated or not, and functional outcome was dichotomized as either independent or not independent at last follow-up.

RESULTS

Over a 23-year period, 39 lesions were treated. Of these, 3 were located in the medulla, 14 in the pons, and 22 in the midbrain. At presentation, 92% of the patients had hemorrhage, and only 43.6% were functionally independent. Surgery resulted in the best radiographic cure rates, with a morbidity rate of 12.5%. In all, 53% of patients either improved or remained stable after surgery. Absence of residual nidus and female sex correlated with better outcomes.

CONCLUSIONS

Brainstem AVMs usually present with hemorrhage. Surgery offers the best chance of cure, either in isolation or in combination with other modalities as appropriate.

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Cary D. Alberstone, Edward C. Benzel and Deborah Garcia

Although trends in the marketplace demand for neurosurgeons should be of interest to neurosurgeons and prospective neurosurgeons, little data are available that accurately document these trends. A recent report published in the general medical journal Journal of the American Medical Association (JAMA) used the Conference Board help-wanted index to evaluate trends in physician marketplace demand. The authors of the JAMA study concluded that over the past 5 years there has been a significant fall in demand for specialist physicians. Because the discipline of neurosurgery was not included in the JAMA study, the authors of the present report attempt to evaluate the trend in the marketplace demand for neurosurgeons, using the same methodology of the JAMA study. The authors' data suggest that the conclusion of the JAMA study of steep declines in the demand for specialist physicians does not accurately reflect the job market for neurosurgeons, which in fact appears to be relatively stable. The present study attempts to document the stability of the neurosurgery market and outline the steps necessary to protect this market from existing threats.

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Thomas J. Leipzig, Kathleen Redelman and Terry G. Horner

✓ Previous studies on the initial nonoperative management of aneurysmal subarachnoid hemorrhage (SAH) demonstrated that antifibrinolytic therapy reduced the risk of rebleeding by approximately 50%; however, prolonged antifibrinolytic treatment was associated with an increase in the incidence of hydrocephalus and delayed ischemic deficit. When early surgical intervention became routine for ruptured aneurysms, the use of antifibrinolytic therapy diminished. However, early surgery is generally performed in the first several days after SAH and the risk of rebleeding remains until the aneurysm is obliterated. Based on a review of the literature, the authors formed two hypotheses: 1) the high-dose intravenous administration of epsilon-aminocaproic acid (EACA), an antifibrinolytic agent, might reduce the risk of recurrent hemorrhage in the interval between SAH and early surgical intervention, and 2) a short course of EACA might not produce the increase in complications previously associated with its prolonged administration.

The use of preoperative high-dose EACA therapy was evaluated in 307 patients to determine its safety and efficacy in reducing the incidence of rebleeding before early aneurysm surgery. All patients were admitted within 3 days of their SAH and were classified as Hunt and Hess Grades I to III. Only four patients (1.3%) suffered a recurrent hemorrhage. This compares favorably to the rebleeding rate of 5.7% reported for the early surgery group in the International Cooperative Study on the Timing of Aneurysm Surgery.

The incidence of hydrocephalus or symptomatic vasospasm was not unduly elevated in patients receiving preoperative EACA. Thirty-five patients (11.4%) needed temporary cerebrospinal fluid drainage during their hospitalization and, overall, 8.8% required a ventriculoperitoneal shunt. The mean age of the patients who required a shunt was nearly 10 years older than the general study population. Seventy-one patients (23%) developed symptomatic vasospasm and 8.1% suffered a stroke.

This study indicates that a brief course of high-dose EACA is safe and may be beneficial in diminishing the risk of rebleeding in good-grade patients prior to early surgical intervention. Further investigation is planned based on these promising results.

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Huan Wang, William Olivero, Giuseppe Lanzino, William Elkins, Jean Rose, Debra Honings, Mary Rodde, Jan Burnham and David Wang

Object

Hypothermia is by far the most potent neuroprotectant. Nevertheless, timely and safe delivery of hypothermia remains a clinical challenge. To maximize neuroprotection yet minimize systemic complications, ultra-early delivery of selective cerebral hypothermia by Emergency Medical Service (EMS) personnel in the field would be advantageous. The authors (W.E. and H.W.) have developed a cooling helmet by using National Aeronautics and Space Administration spinoff technology. In this study its effectiveness in lowering brain temperature in patients with severe stroke or head injury is examined.

Methods

Patients were randomly assigned to groups receiving either the cooling helmet or no cooling, and brain temperatures (0.8 cm below the cortical surface) were continuously monitored for a mean of 48 to 72 hours with a Neurotrend sensor and then compared with the patients' core temperatures. There were eight patients in the study group and six in the control group. The mean change in temperature (brain — body temperature) calculated from 277 data hours in the study group was − 1.6°C compared with a mean change in temperature of + 0.22°C calculated from 309 data hours in the control group. This was statistically significant (p < 0.0001). On average, 1.84°C of brain temperature reduction (range 0.9–2.4°C) was observed within 1 hour of helmet application. It took a mean of 3.4 hours (range 2–6 hours) to achieve a brain temperature lower than 34°C and 6.67 hours (range 1–12 hours) before systemic hypothermia (< 36°C) occurred. Use of the helmet resulted in no significant complications. There was, however, one episode of asymptomatic bradycardia (heart rate < 40) that responded to a 0.5°C body temperature increase.

Conclusions

This helmet delivers initial rapid and selective brain cooling and maintains a significant temperature gradient between the core and brain temperatures throughout the hypothermic period to provide sufficient regional hypothermia yet minimize systemic complications. It results in delayed systemic hypothermia, creating a safe window for possible ultra-early delivery of regional hypothermia by EMS personnel in the field.

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A 10-year experience in the treatment of trigeminal neuralgia

Comparison of percutaneous stereotaxic rhizotomy and posterior fossa exploration

Harry van Loveren, John M. Tew Jr., Jeffrey T. Keller and Mary A. Nurre

✓ Of 1000 patients with classic trigeminal neuralgia who were treated during the last 10 years, 90% had an initial favorable response to medical therapy, but 75% (750 patients) failed to achieve satisfactory long-term relief. Of these, 700 patients were treated by percutaneous stereotaxic rhizotomy (PSR) and 50 were selected for posterior fossa exploration (PFE).

Of the 50 patients undergoing PFE, 82% had neurovascular contact at the trigeminal root entry zone, but only 46% were judged to have had significant neurovascular compression. Exploration was negative in 16% of patients and revealed neural compression by bone in 2%. Patients with neurovascular compression were treated by microvascular decompression (MVD); all other patients with exploratory surgery underwent partial sensory rhizotomy. At 3 years after PFE, 84% of patients are pain-free. Results are excellent in 68%, good in 12%, fair in 4%; 12% had a recurrence of their neuralgia. The 700 patients treated by PSR have been followed for 6 years. Results are excellent in 61%, good in 13%, fair in 5%, and poor in 1%; 20% had a recurrence.

This study indicates that there is no significant difference in results between PSR and PFE in the treatment of trigeminal neuralgia. The concept that neurovascular compression is a mechanical factor in the etiology of trigeminal neuralgia was supported, but neurovascular compression was less common than previously reported. Percutaneous stereotaxic rhizotomy is a less formidable procedure than PFE, and is easily repeated. Recent technical advances have improved the results obtained with PSR. Therefore, PSR remains the procedure of choice for the majority of patients with trigeminal neuralgia.

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Edward C. Benzel, Charles D. Gross, Theresa A. Hadden, Lee Kesterson and Michael D. Landreneau

✓ By conventional criteria, an apneic patient's PaCO2 must be greater than 60 mm Hg before apnea can be attributed to brain death. The rate of a PaCO2 increase in the apneic patient traditionally has been thought to be in the range of 3 mm Hg/min. In order to assess the validity of these data and the validity of the “apnea test” for determination of brain death, the results of this test were reviewed in 20 patients. In all patients, arterial blood samples were drawn for blood gas measurements every 2 minutes following the cessation of volume ventilation (with an oxygen cannula at 6 liters O2/min passed into the tracheobronchial tree).

The rate of PaCO2 increase was noted to be very erratic. The average rate of rise was 3.7 ± 2.3 mm Hg/min (± standard deviation). This, however, varied from 0.5 to 10.5 mm Hg/min and was not predictable from the variables evaluated. The rate of PaCO2 increase was noted to decline throughout the duration of the test. This ranged from 3.9 ± 1.2 mm Hg/min (for patients with baseline PaCO2 ≤ 30 mm Hg) and 4.5 ± 1.9 mm Hg/min (for patients with baseline PaCO2 ≥ 30 mm Hg) in the first 4 minutes of the test to an average of 0.92 mm Hg/min for patients with test lasted longer than 12 minutes. These unpredictable results might be related to CO2 washout, atelectasis, cardiac ventilations, or other yet-undefined parameters.

The nonlinear relationship between rate of PaCO2 increase and time following onset of apnea resulted in the test being prolonged in several patients. In these patients, the PaCO2 approached 60 mm Hg in an asymptotic fashion. These lengthy tests could have been avoided by utilizing a standardized apnea test with a baseline PaCO2 of 40 mm Hg or greater.

The observation that a high baseline PaCO2 greatly augments the efficiency and safety of the test allows criteria that have previously been based on conjecture to be documented and applied clinically. A standardized apnea test, utilizing these principles, may satisfy many of the criticisms regarding brain-death testing that have been raised by neurologists, neurosurgeons, and transplant surgeons.

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Jeffrey E. Florman, Deborah Cushing, Lynne A. Keller and Anand I. Rughani

OBJECTIVE

Selecting the appropriate patients undergoing craniotomy who can safely forgo postoperative intensive care unit (ICU) monitoring remains a source of debate. Through a multidisciplinary work group, the authors redefined their institutional care process for postoperative monitoring of patients undergoing elective craniotomy to include transfer from the postanesthesia care unit (PACU) to the neurosurgical floor. The hypothesis was that an appropriately selected group of patients undergoing craniotomy could be safely managed outside the ICU in the postoperative period.

METHODS

The work group developed and implemented a protocol for transfer of patients to the neurosurgical floor after 4-hour recovery in the PACU following elective craniotomy for supratentorial tumor. Criteria included hemodynamically stable adults without significant new postoperative neurological impairment. Data were prospectively collected including patient demographics, clinical characteristics, surgical details, postoperative complications, and events surrounding transfer to a higher level of care.

RESULTS

Of the first 200 consecutive patients admitted to the floor, 5 underwent escalation of care in the first 48 hours. Three of these escalations were for agitation, 1 for seizure, and 1 for neurological change. Ninety-eight percent of patients meeting criteria for transfer to the floor were managed without incident. No patient experienced a major complication or any permanent morbidity or mortality following this care pathway.

CONCLUSIONS

Care of patients undergoing uneventful elective supratentorial craniotomy for tumor on a neurosurgical floor after 4 hours of PACU monitoring appears to be a safe practice in this patient population. This tailored practice safely optimized hospital resources, is financially responsible, and is a strong tool for improving health care value.

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M. Harrison Snyder, Leonel Ampie, Vernon J. Forrester, JoAnne C. Wilson, James H. Nguyen, Christopher I. Shaffrey and Avery L. Buchholz

Pyoderma gangrenosum (PG) is a rare inflammatory dermatosis that is most often associated with inflammatory bowel disease, but which can occur as a pathergic reaction around surgical incisions. The authors report the case of a patient who developed postoperative PG over the course of several months after undergoing extensive spinal instrumentation between the T4 and iliac levels. This is only the second such case occurring after spine surgery to be reported. The authors additionally review the literature to characterize treatment approaches and outcomes for this condition. The case highlights a potentially severe adverse effect of surgery that can be difficult to recognize and causes delays in effective treatment. It also demonstrates the importance of multidisciplinary collaboration in the effective care of patients.

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Nancy McLaughlin, Amy A. Eisenberg, Pejman Cohan, Charlene B. Chaloner and Daniel F. Kelly

Object

Endoscopy as a visual aid (endoscope assisted) or as the sole visual method (fully endoscopic) is increasingly used in pituitary adenoma surgery. Authors of this study assessed the value of endoscopic visualization for finding and removing residual adenoma after initial microscopic removal.

Methods

Consecutive patients who underwent endoscope-assisted microsurgical removal of pituitary adenoma were included in this study. The utility of the endoscope in finding and removing residual adenoma not visualized by the microscope was noted intraoperatively. After maximal tumor removal under microscopic visualization, surgeries were categorized as to whether additional tumor was removed via endoscopy. Tumor removal and remission rates were also noted. Patients undergoing fully endoscopic tumor removal during this same period were excluded from the study.

Results

Over 3 years, 140 patients (41% women, mean age 50 years) underwent endoscope-assisted adenoma removal of 30 endocrine-active microadenomas and 110 macroadenomas (39 endocrine-active, 71 endocrine-inactive); 16% (23/140) of patients had prior surgery. After initial microscopic removal, endoscopy revealed residual tumor in 40% (56/140) of cases and the additional tumor was removed in 36% (50 cases) of these cases. Endoscopy facilitated additional tumor removal in 54% (36/67) of the adenomas measuring ≥ 2 cm in diameter and in 19% (14/73) of the adenomas smaller than 2 cm in diameter (p < 0.0001); additional tumor removal was achieved in 20% (6/30) of the microadenomas. Residual tumor was typically removed from the suprasellar extension and folds of the collapsed diaphragma sellae or along or within the medial cavernous sinus. Overall, 91% of endocrine-inactive tumors were gross-totally or near-totally removed, and 70% of endocrine-active adenomas had early remission.

Conclusions

After microscope-based tumor removal, endoscopic visualization led to additional adenoma removal in over one-third of patients. The panoramic visualization of the endoscope appears to facilitate more complete tumor removal than is possible with the microscope alone. These findings further emphasize the utility of endoscopic visualization in pituitary adenoma surgery. Longer follow-ups and additional case series are needed to determine if endoscopic adenomectomy translates into higher long-term remission rates.