Month: December 2010

Posted on

Tractography of the amygdala and hippocampus: anatomical study and application to selective amygdalohippocampectomy

J Neurosurg 113:1135–1143, 2010.(DOI: 10.3171/2010.3.JNS091832)

The aim of this study was to evaluate, using diffusion tensor tractography, the white matter fibers crossing the hippocampus and the amygdala, and to perform a volumetric analysis and an anatomical study of the connections of these 2 structures. As a second step, the authors studied the white matter tracts crossing a virtual volume of resection corresponding to a selective amygdalo-hippocampectomy.

Methods. Twenty healthy right-handed individuals underwent 3-T MR imaging. Volumetric regions of interest were manually created to delineate the amygdala, the hippocampus, and the volume of resection. White matter fiber tracts were parcellated using the fiber assignment for continuous tracking tractography algorithm. All fibers were registered with the anatomical volumes.

Results. In all participants, the authors identified fibers following the hippocampus toward the fornix, the splenium of the corpus callosum, and the dorsal hippocampal commissure. With respect to the fibers crossing the amygdala, the authors identified the stria terminalis and the uncinate fasciculus. The virtual resection disrupted part of the fornix, fibers connecting the 2 hippocampi, and fibers joining the orbitofrontal cortex. The approach created a theoretical frontotemporal disconnection and also interrupted fibers joining the temporal pole and the occipital area.

Conclusions. This diffusion tensor tractography study allowed for good visualization of some of the connections of the amygdala and hippocampus. The authors observed that the virtual selective amygdalohippocampectomy disconnected a large number of fibers connecting frontal, temporal, and occipital areas

Posted on

Can systematic analysis of morbidity and mortality reduce complication rates in neurosurgery?

Acta Neurochir (2010) 152:2013–2019. DOI 10.1007/s00701-010-0822-3

Morbidity and mortality conferences (M&MC) are a traditional part of residency programs in a large number of countries to increase the training quality. The purpose of the present publication is to report our experience with a monthly M&MC over a 5-year period and, in particular, to describe the methods to identify critical cases, the system of analysis, classification of morbidity and mortality, and the resulted impact.

Method Monthly identification of M&M was done through a system of electronically coding hospital course at the time of discharge. Morbidity was classified as moderate if sequels resolved within 3 months or otherwise as severe. Morbidity included management complications not directly related the neurosurgical procedure, such as pneumonia or thromboembolism. Mortality was classified as related to surgery or unrelated, e.g., after severe trauma. Mortality in relation to surgery was subclassified in terms of causal relation or not. Statistical comparison of incidence rates was calculated statistically.

Results Overall management morbidity rate was 7.1%, and mortality with causal relation to surgery was 0.38%. The leading cause of morbidity was additional neurological deficit (25%) followed by postoperative hemorrhage (23%) and second unplanned surgery due to incomplete result of the primary procedure (14%). Overall, the monthly incidence varied without a discernable annual pattern. Over the years, there were only a handful of guideline updates triggered by incidents.

Conclusion Our system to identify complication proved to be reliable. During the study period, the M&MC developed into a well-accepted instrument of quality control and problem-oriented teaching, but the impact on quality improvement remained questionable.

Posted on

Morbidity of Transcallosal and Transcortical Approaches to Lesions in and Around the Lateral and Third Ventricles: A Single-Institution Experience

Neurosurgery 67:1483–1496, 2010 DOI: 10.1227/NEU.0b013e3181f7eb68

Resection of an intraventricular mass can result in life-altering complications. Many advocate transcallosal rather than transcortical approaches to these lesions, citing differential postoperative seizure risk.

OBJECTIVE: To test the hypothesis that the complication rates and patient outcomes are no different between these ventricular approaches.

METHODS: The medical records of 127 patients (93 adults and 34 children) operated on for intraventricular lesions between 1996 and 2007 were retrospectively analyzed. Risk factors for specific postoperative complications and outcome were assessed by multivariate analysis.

RESULTS: The transcallosal (59%) or transcortical (41%) approach was used. Gross or nearly total resection was achieved in 87% of cases. The permanent neurological complication rate determined by a staff neurologist was 23.6%. Seizure attributable to surgery occurred after 8% of transcortical and 25% of transcallosal operations (P = .01). After controlling for a variety of factors, the transcallosal approach carried a 4.4-fold increased risk of seizure (95% confidence interval, 1.3-18.9). The operative approach was not a risk factor for any other postoperative complication. One year after surgery, 72% of patients had excellent functional outcome (Karnofsky Performance Score $ 70 and Glasgow Outcome Score = 5). High tumor grade and impaired preoperative Karnofsky Performance Score predicted poor outcome. More than 90% of patients operated on for symptomatic colloid cysts (n = 34) had an excellent outcome.

CONCLUSION: Although the 2 traditional approaches to the ventricular system had similar major complication rates, the transcallosal approach was associated with significantly increased seizure risk. Accordingly, the chosen operative corridor should optimize tumor access and the protection of vulnerable neurovascular structures.

Proudly powered by WordPress