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Joe Sam Robinson and Robert A. Moody

✓ The effects of acute hypertension and respiratory stress induced by Aramine (metaraminol bitartrate) upon blood-brain barrier (BBB) permeability to horseradish peroxidase (HRP) were studied in adult inbred white rats. The BBB permeability was quantitated by slicing the brain of each animal into 500-µ thick sections, incubating the sections using the Reese-Karnovsky method, and counting all observed HRP perivascular exudates. No evidence of BBB compromise or significant elevation of blood pressure (BP) was observed in the following experimental groups: 1) control group of five animals; 2) hyperventilated group of five animals (final mean arterial blood gases: pO2, 104.2 mm Hg; pCO2, 24.8 mm Hg; pH, 7.53); 3) anoxicstress group of five animals (final mean arterial blood gases: pCO2, 31.4 mm Hg; pCO2, 58.2 mm Hg; pH, 7.21). However, in a group of 15 animals subjected to anoxic stress followed by hyperventilation, in addition to extreme changes in the levels of arterial blood gases, a significant BP increase occurred (mean BP increase per second, 3.43 ± 0.25 mm Hg; final mean BP, 163.3 ± 3.18 mm Hg); as well as significant BBB opening (mean number of HRP exudates per animal, 12.2 ± 0.85). Likewise, a final group of 10 animals given intravenous Aramine displayed a significant systemic BP elevation (mean BP increase per second, 6.9 ± 0.38 mm Hg; final mean BP, 165.8 ± 3.16 mm Hg), accompanied by BBB opening (mean number of exudates per animal, 51.5 ± 5.95). The variable most strongly associated with the degree of barrier opening was the rate of BP rise (correlation coefficient = + 0.84).

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M. Sami Walid and Joe Sam Robinson Jr.

Object

Comorbidities in patients undergoing spine surgery may reasonably be factors that increase health care costs. To verify this hypothesis, the authors conducted the following study.

Methods

Major comorbidities and age-adjusted Charlson Comorbidity Index scores were retrospectively analyzed for 816 patients who underwent spine surgery at the authors' institutions between 2005 and 2008, and treatment costs (hospital charges) were assessed with the help of statistical software. The sample was collected by a nonmedical staff (hired at the beginning of 2006). Patients underwent one of the three most common types of spine surgery: lumbar microdiscectomy (20.5%), anterior cervical decompression and fusion (ACDF; 60.3%), or lumbar decompression and fusion (LDF; 19.2%). Patients were nearly equally divided by sex (53% were female and 47% male), and 78% were Caucasian versus 21% who were African American; the rest were of mixed or unidentified race. The average age was 54 years, with an SD of ± 14 years.

Results

There were significant differences in the prevalence of major comorbidities between male and female and between severely obese and nonseverely obese patients. The impact of comorbidities on the cost of spine surgery was more prominent in older patients, and an additive effect from some comorbidities was recorded in various types of spine surgery. For instance, in the ACDF group, female patients with both severe obesity and diabetes mellitus (DM) had significantly higher hospital charges than those with only one or neither of these conditions ($34,943 for both severe obesity and DM vs $25,633 for severe obesity only; $25,826 for DM only; and $25,153 for those with neither condition [p < 0.05]). In the LDF group, female patients with both DM and a history of depression had significantly higher hospital charges than those with only one or neither of these conditions ($65,782 for both DM and depression vs $53,504 for DM only; $55,990 for depression only; and $52,249 for those with neither condition [p < 0.05]). A significant difference was also found in hospital cost ($16,472 [p < 0.01]; 32% increase over baseline) in the LDF group between patients with the lowest and highest scores on the Charlson Index.

Conclusions

Comorbidities additively increase hospital costs for patients who undergo spine surgery, and should be considered in payment arrangements.

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Cervical epidural hematoma in children: a rare clinical entity

Case report and review of the literature

Kostas N. Fountas, Eftychia Z. Kapsalaki, and Joe Sam Robinson

✓ Pediatric spinal epidural hematoma is a very rare clinicopathological entity. In the vast majority of cases, spinal epidural hematomas have a nonspecific clinical presentation; this, along with their rapid progression, makes their early diagnosis and prompt surgical evacuation critical. Magnetic resonance imaging is the neuroimaging modality of choice, whereas hemilaminectomy or laminectomy is the indicated surgical intervention. The outcome is good when hematoma evacuation is performed before the onset of complete sensorimotor paralysis.

In this communication, the authors describe a 12-year-old girl with a traumatic acute cervical epidural hematoma. This lesion was successfully evacuated through a hemilaminectomy, and the patient had an excellent outcome. The pertinent literature is reviewed in terms of the incidence, origin, management, and prognosis of this rare and potentially disastrous clinical entity.

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Familial intracranial ependymomas

Report of three cases in a family and review of the literature

Vassilios G. Dimopoulos, Kostas N. Fountas, and Joe Sam Robinson

Familial cases of intracranial ependymomas have been well documented in the literature. The authors present two cases from a family in which three members harbored intracranial ependymomas. A 54-year-old man with fourth ventricular ependymoma underwent resection of the tumor followed by radiation therapy. His son presented at age 36 years with a fourth ventricular tanycytic ependymoma and underwent total resection of the ependymoma with postoperative radiation therapy. The father's sister had been treated at another institution for a posterior fossa ependymoma. The association of ependymomas with molecular genetic alterations in chromosome 22 has been previously described. Further investigation of the genetic influences may lead to better therapeutic approaches for this relatively rare clinicopathological entity.

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Theofilos G. Machinis, Kostas N. Fountas, Vassilios Dimopoulos, and Joe Sam Robinson

The purpose of this article is to provide insight into the development of surgery for acoustic neurinomas throughout the years. The significant contribution of surgical authorities such as Cushing, Dandy, and House are discussed. The advances in surgical techniques from the very first operations for acoustic tumors at the end of the 19th century until today are described, with special emphasis on the technological and diagnostic milestones that preceded each step of this development.

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Carlos Feltes, Kostas Fountas, Rostislav Davydov, Vassilios Dimopoulos, and Joe Sam Robinson Jr.

The authors studied whether the amount of retraction pressure applied to a compromised nerve root during lumbar discectomy has an impact on intra- or postoperative outcome.

Methods

The authors conducted a prospective analysis of 20 patients. There were 12 men and 12 women whose mean age (± standard deviation [SD]) was 42.25 years ± 15 years (range 21–65 years). During intraoperative electromyography (EMG) monitoring, measurements were obtained during routine retraction of the affected nerve root by using a specially designed and constructed nerve root retractor connected to a reconfigured personal computer for this specific purpose. Follow-up results were assessed in the immediate postoperative period and at up to 1 year. The maximum measured force applied during random periods of time was 9.85 N/second (mean 6.95 ± N/second [± SD]). The mean retraction time was 39.5 ± 21 (SD). No intraoperative EMG-detected irritation was noted during or after routine retraction. In four of 20 patients, sensory changes occurred at the ipsilateral nerve root level, which resolved at the time of discharge.

Conclusions

The authors found that routine nerve root retraction does not cause nerve root irritation, as demonstrated by EMG monitoring, nor was patient outcome affected in this series.

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Ioannis Karampelas, Angel N. Boev III, Kostas N. Fountas, and Joe Sam Robinson Jr.

The authors offer a brief overview of early theories and treatments of sciatica. Tracing medical traditions through early Greek, Roman, and Eastern epochs, the authors demonstrate the slow sequential steps that were required to delineate this disease as a uniquely human affliction.

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Theofilos G. Machinis, Kostas N. Fountas, John Hudson, Joe Sam Robinson, and E. Christopher Troup

Objective

Ventriculoatrial (VA) shunts remain a valid option for the treatment of hydrocephalus, especially in patients in whom ventriculoperitoneal (VP) shunts fail. Correct positioning of the distal end of the catheter in the right atrium is of paramount importance for maintaining shunt patency and reducing the incidence of VA shunt-associated morbidity. The authors present their experience with real-time transesophageal echocardiography (TEE) monitoring for the accurate placement of the distal catheter of a VA shunt.

Methods

Four patients underwent conversion of a VP shunt to a VA shunt under the guidance of intraoperative fluoroscopy and TEE between May 2003 and December 2004. After induction of general anesthesia, the TEE transducer was advanced into the esophagus. A cervical incision was made and the external jugular vein was visualized. An introducer was passed through an opening in the jugular vein and a guidewire was placed through the introducer. Under continuous TEE guidance, the guidewire was carefully advanced into the superior vena cava. A distal shunt catheter overlying a J-wire was then passed to the superior vena cava, again under TEE guidance. The catheter was advanced to the right atrium after removing the guidewire.

Final visualization with TEE and fluoroscopy revealed a good position of the catheter in the right atrium in all four cases. The mean duration of the operation was 91 minutes (range 65–120 minutes) and the mean operative blood loss was 23 ml (range 10–50 ml). No procedure-related complication was noted.

Conclusions

Real-time TEE is a safe and simple technique for the accurate placement of the distal catheter of a VA shunt.

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Vassilios Dimopoulos, Kostas N. Fountas, Theofilos G. Machinis, Carlos Feltes, Induk Chung, Kim Johnston, Joe Sam Robinson, and Arthur Grigorian

Cauda equina syndrome is a well-documented complication of uneventful lumbar microdiscectomy. In the vast majority of cases, no radiological explanation can be obtained. In this paper, the authors report two cases of postoperative cauda equina syndrome in patients undergoing single-level de novo lumbar microdiscectomy in which intraoperative electrophysiological monitoring was used. In both patients, the amplitudes of cortical and subcortical intraoperative somatosensory evoked potentials (SSEPs) abruptly decreased during discectomy and foraminotomy. In the first patient, a slow, partial improvement of SSEPs was observed before the end of the operation, whereas no improvement was observed in the second patient. In the first case, clinical findings consistent with cauda equina syndrome were seen immediately postoperatively, whereas in the second one the symptoms developed within 1.5 hours after the procedure. Postoperative magnetic resonance images obtained in both patients, and a lumbar myelogram obtained in the second one revealed no signs of conus medullaris or nerve root compression. Both patients showed marked improvement after an intense course of rehabilitation. The authors' findings support the proposition that intraoperative SSEP monitoring may be useful in predicting the development of cauda equina syndrome in patients undergoing lumbar microdiscectomy. Nevertheless, further prospective clinical studies are necessary for validation of these findings.

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Kostas N. Fountas, Robert S. Donner, Leonidas G. Nikolakakos, Carlos H. Feltes, Ioannis Karampelas, and Joe Sam Robinson Jr.

✓ The authors report a unique case of diffuse spinal metastatic disease due to a pleomorphic rhabdomyosarcoma (RMS) in an adult. In additon to its overall rarity, peculiar characteristics of the particular tumor included its site of origin, demonstrated radiologically as the lumbar paravertebral musculature (psoas muscle) and the transcanalicular spread into the vertebral canal, resulting in thecal compression at multiple levels. The salient clinicopathological characteristics of RMS, as they related particularly to the spine, are subsequently discussed and a short review of the major therapeutic modalities for these tumors is offered.