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Career Choice↗
Biomedical subjects
B C Walters
Publications and source records attributed to B C Walters.
A randomized controlled trial of perioperative rifampin/trimethoprim in cerebrospinal fluid shunt surgery.
A randomized, double-blind, placebo-controlled trial of perioperative rifampin-trimethoprim was undertaken at the Hospital for Sick Children from March 1984 to October 1987, in which 243 patients undergoing 300 cerebrospinal fluid (CSF) shunting procedures were randomized into groups including treatment with rifampin/trimethoprim and placebo, and then followed for a minimum of 2 years. Patients were stratified prior to randomization into those with and those without meningo-myeloceles having first insertions of their shunts, and those having revisions. Patients could be entered into the study more than once, but always received the same treatment regimen once allocation had taken place. Among the patients receiving antibiotics there was an infection rate of 12%, versus 19% among patients receiving placebo. Among the surgical procedures, the rates were 9% and 15%, respectively. Because these rates of infection were a substantial increase over the rate of 7.5% overall for the few years prior to implementation of the study, and well over any acceptable rate of infection, the study was stopped before statistical significance was reached. However, had the study continued, and the proportions of patients becoming infected remained constant, we would have been able to achieve a statistically significant difference in rates of infection, and therefore demonstrate a benefit of rifampin/trimethoprim as prophylaxis against shunt infection. Methodological problems encountered in this and other studies of prevention of CSF shunt infection will be discussed.
Adolescent↗
Cerebrospinal fluid shunt infection.
There are distinct clinical situations in which the various methods of treatment are generally used: 1. Medical therapy may be used in the circumstance of an infected, but functioning shunt. However, once a shunt is shown to be malfunctioning, it must be treated surgically to correct both the malfunction and the infection. 2. The one combination therapy that continues to treat the hydrocephalus while obeying surgical principles to remove an infected prosthesis is that of immediate shunt replacement. However, this mode of therapy has worked infrequently. 3. The form of combined surgical and medical therapy that allows time to sterilize the CSF in the absence of a foreign body in situ is that of delayed replacement following removal of the infected shunt. However, this method temporarily discontinues the treatment of hydrocephalus. 4. External ventricular drainage removes the foreign body and continues to treat the hydrocephalus; however, this therapy places the patient at increased risk for more virulent infection. With these points in mind, an algorithm for the treatment of shunt infection can be developed as depicted in Figure 8. Using this common sense approach, most circumstances commonly encountered in the practice of pediatric neurosurgery are dealt with, and the best hope of cure is obtained.
Anti-Bacterial Agents↗
Venous thromboembolism after brain tumor surgery: a retrospective review.
We retrospectively reviewed the incidence rate of clinical postoperative deep vein thrombosis and/or pulmonary embolism in 1703 patients undergoing initial craniotomy for meningioma, glioma, or cerebral metastasis. The incidence rate of clinical thromboembolic complications was 1.59% for all tumor groups within the first 4 weeks of surgery. Patients undergoing surgery for meningiomas had a statistically significant increased risk of thromboembolism despite fewer overall perioperative risk factors, when compared with the other tumor groups. The tumor-specific incidence rates of deep vein thrombosis and/or pulmonary embolism for meningioma, glioma, and metastasis were 3.09%, 0.97%, and 1.03%, respectively. Whether this difference was a result of increased surgical time or an inherent property of meningiomas could not be ascertained.
Adult↗
Unilateral megalencephaly associated with neonatal high output cardiac failure.
High-flow cerebral arteriovenous fistulae are well known to present in the neonatal period with macrocephaly, cranial bruits and high-output cardiac failure. This report describes a newborn infant with such a clinical presentation, who had unilateral megalencephaly without macroscopic arteriovenous shunts. Ultrasound Doppler examination of the carotid and cerebral vessels showed diastolic flow, or a decreased pulsatility index, consistent with decreased intracranial vascular resistance. The ipsilateral cerebral arteries and veins were markedly enlarged at angiography and at post-mortem examination, but there was no arteriovenous malformation. The infant expired from high-output cardiac failure and hypoglycemia. It is postulated that the high-output cardiac failure was due to increased blood flow through the enlarged, dysplastic cerebral hemisphere.
Brain↗
Improving the record of patient assessment in the trauma room.
To facilitate clinical research at the Regional Trauma Unit at Sunnybrook Medical Centre in Toronto, it was decided to attempt to improve the quality and quantity of clinical patient information obtained at initial assessment in the Trauma Room. Standardized patient forms were introduced to replace the narrative record, including forms for the Trauma Team Leader, Anesthesia, General Surgery, Neurosurgery, Orthopedic Surgery, and Plastic Surgery. These forms were evaluated in this study which compared 100 charts generated before introduction of the forms to 100 charts generated following the implementation of the forms, with respect to certain items of patient demography and clinical condition. There was a statistically significant improvement in amount of information collected and in a format which facilitates data storage and retrieval. This, in turn, establishes an excellent standardized database for clinical trials in trauma care.
Emergency Medical Service Communication Systems↗
The Sunnybrook Neurotrauma Assessment Record: improving trauma data collection.
A neurotrauma assessment record has been designed to aid in data collection and clinical documentation of patients with multiple injuries. The record collects data concerning patient demography, trauma and medical history, neurological and systemic examinations, investigations, and treatment planning. It consists of two pages and the clinician need only circle listed choices, write focused comments, or draw on provided diagrams. It obviates the narrative record of the history and physical examination. We reviewed the written records of 100 consecutive polytraumatized patients seen in the Trauma Room before institution of the form, transcribing their information onto the form. These were compared to a second series of 100 consecutive patients who were evaluated following the introduction of the neurotrauma form as the initial assessment record. Seventy-seven of these patients were evaluated by the Neurosurgical service. Overall, the quality and completeness of recording improved dramatically. The neurotrauma assessment record ensures more complete recording of information during initial patient assessment, allows easy transfer to computerized databases, and may assist academic centres in performing clinical research.
Humans↗
Decreased risk of infection in cerebrospinal fluid shunt surgery using prophylactic antibiotics: a case-control study.
Four randomised controlled trials have focussed on the use of prophylactic antibiotics in the prevention of cerebrospinal fluid (CSF) shunt infection. None of these studies has been able to demonstrate a statistically significant difference in rate of infection. This may be due to the inadequate power of the studies to detect a clinically significant difference, as a result of small sample size. This retrospective case control study was designed using the same basic principles of avoidance of bias which make randomised controlled trials the model studies for generation of scientific evidence. It has found a highly statistically significant difference in the use of antibiotics among infected compared to non-infected patients, suggesting a three times greater risk of infection among patients who did not receive antibiotics. This study provides the strongest evidence to date regarding the usefulness of perioperative antibiotics in CSF shunt surgery.
Adolescent↗
Cerebrospinal fluid shunt infection. Influences on initial management and subsequent outcome.
A retrospective study of the management of patients with infected cerebrospinal fluid (CSF) shunts was undertaken, covering the 20 years from 1960 to 1979, inclusive, and involving 222 patients with 267 infections. The data were analyzed with emphasis on influences surrounding treatment choice and subsequent outcome. Treatment was classified into three major categories: medical management (antibiotics alone), surgical management (antibiotics plus operative removal of the infected shunt), and no treatment (ranging from admission and observation only to shunt revision), the diagnosis of shunt infection having been missed. Results showed surgical treatment to be more efficacious than medical or no treatment, with a higher rate of initial cure, and lower morbidity and mortality rates. Also examined were the relationships among clinical presentation, infection rate, and results of specimens sent for culture, and initial treatment. The definitive nature of initial treatment was revealed to be directly proportional to the aggressiveness of microbiological investigation. This latter aspect was related to clinical presentation, with shunt malfunction being the least recognized symptom of shunt infection. Patients presenting with blocked shunts were less likely to receive therapy appropriate for infection than any other group, leading to the conclusion that shunt malfunction may be more specific to infection than heretofore believed.
Anti-Bacterial Agents↗