Ghaus M. Malik

Temporary clipping in aneurysm surgery : technique and results

The use of temporary clipping has become an established tool in the armamentarium of the aneurysm surgeon. Our experience with 62 consecutive patients is presented, detailing operative protocols and results. Twenty-two had unruptured aneurysms (35%), 15 were grade I (24%), 16 grade II (25%), five grade III (8%), and four grade IV (7%). The aneurysms were mainly located in the middle cerebral artery (29 patients) and the anterior communicating artery (13 patients). Eleven of our 62 patients (17%) developed a new, persistent postoperative deficit. However, in only one case (2%) was temporary clipping felt to be implicated in the development of the deficit. In three other patients (5%), the effect of temporary clipping, although unlikely, could not be excluded. Overall, 92% of our patients with temporary clipping had good to excellent outcome, with 3% mortality and 5% morbidity. We believe that temporary clipping is a safe procedure that contributes significantly to a better outcome.

Stereotactic Endoscopic Interventions in Cystic and Intraventricular Brain Lesions

Image guided stereotaxis is an accurate and safe method of directing therapy to target volumes defined in two-dimensional (2D) multiplanes or three-dimensional (3D) perspectives using computer reconstruction of image data. The major limitations of stereotactic techniques are related to a lack of intraoperative visualization and direct monitoring of the procedures and to changes of intracranial coordinates after decompression of cystic lesions or aspiration of cerebrospinal fluid in the management of intraventricular lesions. Endoscopic laser stereotaxis (ELS) involves integration of rigid-flexible endoscopy and Nd-YAG laser to 3D-2D multiplanar image-guided stereotactic procedures. The major advantages of ELS include: direct intraoperative visualization, hemostasis, evacuation or resection assessment, and wide exploration of intracranial cavities or ventricles. The technique allows safe aspiration, biopsy, and resection or internal decompression of deep and subcortical intracranial lesions. ELS has proved to be safe and effective in the management of 76 clinical cases and appears to be a promising technique in the management of cystic and intraventricular lesions.

Hypothermic circulatory arrest and the management of giant and large cerebral aneurysms

The surgical adjuncts of hypothermic circulatory arrest, exsanguination, and barbiturate cerebral protection were evaluated in nine cases of cerebral aneurysms felt unapproachable by conventional surgery. These techniques were used in seven posterior circulation aneurysms, two of which were giant and two giant anterior circulation aneurysms originating at the middle cerebral artery bifurcation. Four patients had excellent outcomes, two had a fair result, one had a poor result, and two died. The outcome of surgery reflected that of the management of patients with unruptured or ruptured aneurysms. Three of the four patients who did well had unruptured aneurysms, and all three of the cases in which death or a poor outcome resulted occurred in patients presenting with subarachnoid hemorrhage. The rationale for the use of hypothermic circulatory arrest is discussed, and the surgical indications, techniques, and anesthetic considerations are also reviewed.

Image- Guided Stereotactic Centered Craniotomy and Laser Resection of Solid Intracranial Lesions

A technique in which solid intracranial lesions are removed using computerized image processing under stereotactic conditions is described. A specially developed carbon fiber ring holder compatible with most image studies is used as a reference system. Intraoperatively it affords freedom of patient positioning and unobstructed access to any site of the head. Four position alternatives of the aiming device allow the removal of lesions from any location. For superficial lesions located near eloquent areas, a centered craniotomy is performed, usually under local anesthesia, and removal is performed using loupe magnification, bipolar coagulation ultrasonic aspiration of the Nd:YAG laser fiber in the contact or noncontact technique. In deep-seated lesions, a surgical corridor is established and kept by means of retractors adapted for use with the stereotactic apparatus. Microsurgical techniques and the CO2 laser are used in solid lesions; in vascular lesions, bipolar coagulation or the ND:YAG laser can be used. Centered craniotomy allows the precise localization, enhancement, three-dimensional orientation and removal of lesions with minimal trauma to the surrounding brain. The technique has been applied in 78 cases where the extreme accuracy of the technique, benign postoperative course and short hospitalization have been impressive.

Tumour Recurrence vs Radionecrosis: an Indication for Multitrajectory Serial Stereotactic Biopsies

External RT has been proved to be an important adjuvant to surgery in the treatment of malignant glioma. It has also been demonstrated, that its effect on survival is dose-dependent, although accompanied by a higher morbidity. Intents to localize the field of high dose RT to the tumour area have been performed with the aim to spare damage of the normal brain tissue. Between August 1983 to December 1987, 40 patients with malignant astrocytoma (16 GM, 24 AA) underwent high dose localized hyperfractionated external RT after surgical resection. Patients received 57.6 Gy to the tumour and oedema area associated with a boost localized to the tumour of 7.4, 14.4 or 24 Gy. In the follow-up, 16 patients died with evidence of increase in size of lesion diagnosed by CT/MRI. Since July 1987, 12 patients with recurrence or increase on size of CT/MRI lesion have undergone multitrajectory serial stereotactic biopsies. From the biopsies 8 patients were histologically diagnosed was compatible with radionecrosis. From the 4 recurrences, 2 patients were treated with 125I implants and 1 with new resection. Patients with radionecrosis were treated with corticoides and diuretics, obtaining partial or complete remission of symptoms and decrease in size of CT lesion. Undoubtly, Multiplanar/3D multitrajectory serial stereotactic biopsies play a major role in the follow-up of these patients, and accurate diagnosis need to be established for further treatment therapy. The question remains if these localized boost should be replaced by 3D Multiplanar stereotactic interstitial radiotherapy boost after surgery and conventional radiotherapy.

Application of Multimodality Imaging Stereotactic Localization in the Surgical Management of Vascular Lesions

Multidimensional image preplanning and accurate pre and intraoperative localization for intracranial vascular lesions have been implemented. Methodology include carbon fiber base ring, localizer plates, any X-ray tubes, PC compatible software and intraoperative localizing unit. Surgical management of deep arteriovenous malformations is especially suitable for this technique, including the use of intraoperative digital angiography.

Multiplanar CT-Guided Stereotaxis and 125I Interstitial Radiotherapy

A method using Multiplanar CT-guided stereotactic biopsy and high-dose 125I interstitial radiotherapy in patients with malignant nonresectable or recurrent brain tumors is presented. Optimal interstitial radiotherapy requires careful preoperative planning, computer-assisted dosimetry, CT-guided stereotactic biopsy and implantation of catheters that will be loaded with 125I seeds. A method is presented by which the isodose curve distribution is adjusted to the tumor size, volume and axis, allowing treatment of the imaged and histologically determined border of the tumor with 60 Gy at a dose rate of 40 rad/h.

Three-dimensional image-guided stereotactic resection of intracranial lesions

Multidimensional tomographic image processing can be used to provide the surgeon useful information on volume, size, shape, location and anatomical relationships of intracranial lesions. Using a reference system this information can be used to simulate and interactively optimize surgical treatment. Finally, this computer generated data can be transposed accurately on the real physical world or can be used to drive instruments such as microscopes, lasers, etc., leading to automation of neurosurgical procedures. The final goal is the optimization of surgical resection of intracranial lesions.

Endoscopic laser stereotaxis: indication for cystic or intraventricular lesions

Image guided stereotaxis is an accurate and safe method of directing therapy to target volumes defined in two-dimensional (2D) multiplanes or three-dimensional (3D) perspectives using computer reconstruction of image data. The major limitations of stereotactic techniques are related to a lack of intraoperative visualization and direct monitoring of the procedures and to changes of intracranial coordinates after decompression of cystic lesions or aspiration of cerebrospinal fluid in the management of intraventricular lesions. Endoscopic laser stereotaxis (ELS) involves integration of rigid-flexible endoscopy and Nd-YAG laser to 3D-2D multiplanar image-guided stereotactic procedures (7). The major advantages of ELS include: direct intraoperative visualization, hemostasis, evacuation or resection assessment, and wide exploration of intracranial cavities or ventricles. The technique allows safe aspiration, biopsy, and resection or internal decompression of deep and subcortical intracranial lesions. ELS has proved to be safe and effective in the management of 72 clinical cases and appears to be a promising technique in the management of cystic and intraventricular lesions.

A Framework for Intracranial Saccular Aneurysm Detection and Quantification using Morphological Analysis of Cerebral Angiograms

Reliable early prediction of aneurysm rupture can greatly help neurosurgeons to treat aneurysms at the right time, thus saving lives as well as providing significant cost reduction. Most of the research efforts in this respect involve statistical analysis of collected data or simulation of hemodynamic factors to predict the risk of aneurysmal rupture. Whereas, morphological analysis of cerebral angiogram images for locating and estimating unruptured aneurysms is rarely considered. Since digital subtraction angiography (DSA) is regarded as a standard test by the American Stroke Association and American College of Radiology for identification of aneurysm, this paper aims to perform morphological analysis of DSA to accurately detect saccular aneurysms, precisely determine their sizes, and estimate the probability of their ruptures. The proposed diagnostic framework, intracranial saccular aneurysm detection and quantification, first extracts cerebrovascular structures by denoising angiogram images and delineates regions of interest (ROIs) by using watershed segmentation and distance transformation. Then, it identifies saccular aneurysms among segmented ROIs using multilayer perceptron neural network trained upon robust Haralick texture features, and finally quantifies aneurysm rupture by geometrical analysis of identified aneurysmic ROI. De-identified data set of 59 angiograms is used to evaluate the performance of algorithms for aneurysm detection and risk of rupture quantification. The proposed framework achieves high accuracy of 98% and 86% for aneurysm classification and quantification, respectively.