The vascular plug: a new device for parent artery occlusion.

Parent artery occlusion (PAO) is still indicated at times for the treatment of craniocervical vascular disease. Because of the unavailability of silicone and latex balloons in the United States, costly combinations of detachable and pushable coils have been required to achieve PAO. We describe our experience with a simple and less expensive alternative for PAO in 4 carotid arteries and 1 vertebral artery. This device is limited to occlusions below the base of the skull.

A cohort study of the safety and feasibility of intraventricular urokinase for nonaneurysmal spontaneous intraventricular hemorrhage.

BACKGROUND AND PURPOSE: Small case series have reported potential benefit from thrombolysis after spontaneous intraventricular hemorrhage (IVH). Our objective was to review our experience using intraventricular urokinase (UK) in treating selected patients with IVH. METHODS: Using medical records, we identified all patients who received ventriculostomies for CT-confirmed nonaneurysmal nontraumatic spontaneous IVH from December 1992 through November 1996. We reviewed charts and CT images and examined the data for associations with specific outcomes. RESULTS: We identified 40 patients, 18 treated with ventriculostomy alone and 22 receiving adjunctive intraventricular UK. The initial Glasgow Coma Scale (GCS) scores of the two groups were similar (P = 0.5). While there was a trend for patients with any intraparenchymal hemorrhage (IPH) to receive UK (P = 0.07), the mean size of IPH in those who received ventriculostomy alone was larger than in those who received adjunctive UK (P = 0.002). There was lower mortality in the group treated with UK (31.8 versus 66.7%; P = 0.03), but there was only a trend toward an increase in favorable outcome (22.2% versus 36.4%; P = 0.3). Overall, the most significant association with outcome was neurological condition at presentation (GCS >5 versus < or = 5; P = 0.003). Receiving UK did not increase the occurrence of complications or hospital length of stay for survivors (P = 0.5). CONCLUSIONS: Intraventricular UK remains a safe and potentially beneficial intervention. While it appeared to lower mortality, a randomized, placebo-controlled trial is needed to explore whether the therapy can increase the incidence of favorable outcomes.

Use of an open stereotactic ring for neurosurgical procedures.

We describe an open ring as a new design to the Zamorano-Dujovny (Z-D) stereotactic unit. The titanium base ring has an opening of 45 degrees that can be located in any chosen position. Imaging studies such as computed tomography, X-ray, positron emission tomography, digital angiography, and digital substraction angiography can be performed with the open stereotactic ring for multimodality image localization. Preoperatively and intraoperatively, this open design provides the anesthesiologist with an unobstructed pathway for airway management. During the surgical procedure, it facilitates approach to any intracranial lesion, including orbitozygomatic, combined supra-infratentorial, and others. During awake craniotomies it not only allows for easy airway management, but also provides good access to the patient's face for intraoperative evaluation of speech and visual functions. Accuracy and reliability of this unit were similar to results obtained with the original circular ring. This system can be used in conventional stereotaxis with the Z-D arc, as well as a reference for intraoperative registration with any digitizer system. The open stereotactic unit is a relatively inexpensive, reliable, and easy-to-use solution for resections using conventional stereotaxis or interactive image guidance in any intracranial site.

Application accuracy study of a semipermanent fiducial system for frameless stereotaxis.

The accuracy of a semipermanent fiducial marker system developed at Wayne State University in collaboration with Fisher-Leibinger (Freiburg, Germany) was compared with reference to a standard stereotactic frame (Zamorano-Dujovny Localizing Unit; Fisher-Leibinger). For each patient in our study, 10 semipermanent markers were placed on the skull through a small incision and a pilot hole drilled for the marker; five markers were used for registration, and five were used for comparison. Gadolinium-enhanced magnetic resonance imaging was performed, and, upon registration using both ring and fiducial markers, 184 random points were collected by infrared digitization. All three-dimensional measurements (x, y, z) were converted into distance values correlating each value to the origin by the formula dij = SQRT (xij2 + yij2 + zij2). The mean difference of fiducial coordinates vs. absolute image coordinates was 1.72 +/- 0.42 mm (P = .0001), implying no significant difference. The mean difference in dij of the stereotactic ring coordinates vs. the absolute image coordinates was 3.35 +/- 0.59 mm (P = .00011). The mean difference in the fiducial markers vs. the stereotactic ring coordinates was 2.95 +/- 0.45 mm (P = .0001). All tests were declared significant at alpha = .016. The combination of interactive guidance with semipermanent fiducial markers allows for accurate localization of intracranial targets (as accurate or even more accurate than the stereotactic frame). Semipermanent fiducial markers facilitate the procedure logistically, allow for staged procedures (i.e., at the skull base or in epilepsy), and provide access for combined supra- and infratentorial approaches. We believe that the semipermanent fiducial markers system might represent an important development leading toward widespread use of interactive image guidance in conventional neurosurgery.

Interactive image-guided resection of cerebral cavernous malformations.

Between July 1992, and February 1997, 15 patients with cavernous malformations underwent interactive image-guided resection of their lesions. There were eight women and seven men in the group, ranging in age from 6 years to 62 years (mean 34 years). Clinical presentations included seizures (n = 7), headache (n = 4), and hemorrhage (n = 4). Prior conventional subtotal resection had been performed in one patient, and a history of prior hemorrhage was found for two patients. Diagnosis was made using magnetic resonance imaging and digital substraction angiography. Locations of the lesions were temporal (n = 9), frontal (n = 3), thalamus (n = 1), basal ganglia (n = 1), and pons (n = 1). Size ranged from 9 to 20 mm (mean 12 mm). For those lesions located near or within eloquent areas (n = 7), an awake craniotomy with functional cortical and subcortical mapping was performed. An infrared system was used intraoperatively to confirm the location and the extent of the resection of these lesions in real time. In 1996 we started using a robotic microscope to aid in localization and resection. Clinical follow-up ranged from 2 to 54 months (mean 27 months). In all 15 patients, complete surgical resection was achieved as demonstrated by postoperative magnetic resonance imaging studies. Two patients had postoperative transient neurological deficits (13.3%) that cleared over a 6-month period. One of them had a lesion in the pons, with multiple cranial nerve deficits postoperatively that gradually improved. There was no associated mortality. Histological diagnosis was consistent with cavernous angioma in all cases. Clinical follow-up revealed that 13 patients experienced complete recovery from preoperative symptoms and two patients with seizures showed marked improvement. We conclude that interactive image-guided surgery for deep-seated cavernous malformations represents a very accurate and safe approach.

Radiosurgical treatment of meningiomas.

From January 1992 to November 1996, 17 patients with the diagnosis of intracranial meningioma underwent radiosurgical treatment. Of these, 7 patients were treated using a Linac-based system (group 1), and 10 using the Leksell Gamma Knife unit (group 2). The follow-up ranged between 12 and 48 (median 33) months for group 1 and between 1 and 11 (median 5) months for group 2, consisting of clinical and MRI assessments every 3 months during the first year, and every 6 months thereafter. There were 14 women and 3 men. The mean age was 42 years. Prior to radiosurgery, 15 patients underwent surgical procedures. Histological diagnosis was consistent with benign meningioma, except in 2 patients (malignant meningioma). In 15 patients with benign meningiomas there was no evidence of tumor growth as demonstrated by clinical and radiological evaluation, in 2 patients with a malignant histological type there was tumor progression.

Interactive intraoperative localization during the resection of intraventricular lesions.

Mass lesions located in the ventricular system can be surgically challenging. These tumors are often slow growing and reach considerable size before they are diagnosed. These lesions commonly cause multiple obstructions to the circulation of cerebrospinal fluid with subsequent hydrocephalus. They are deeply located in the brain, surrounded by vital neurological and vascular structures, and often have irregular configurations. All these characteristics may pose real problems during surgery in terms of orientation and a optimal resection. For the surgical approach to such intraventricular lesions we are currently using an infrared-based system implemented at Wayne State University that allows intraoperative real-time localization. Three infrared cameras continuously track the position of multiple light-emitting diodes in relation to a predetermined "rigid body". This system can be used with different surgical instruments, and does not interfere with standard neurosurgical techniques. We present our preliminary experience in 18 patients with intraventricular tumors that were operated on between December 1992 and March 1995. Their lesions were located in the lateral ventricles, third ventricle, and pineal region with extension into the posterior aspect of the third ventricle. The use of the interactive infrared-based localizing unit allowed a total resection in 15 cases and a subtotal resection in 3 cases. We report 3 complications, but only one of them was related to the surgical procedure. The postoperative follow-up period ranged from 2 to 24 months. All patients were followed clinically and with postoperative magnetic resonance imaging scans. This interactive infrared system has proven to be a very useful tool, flexible, safe and reliable, increasing surgical efficiency, without a significant increase in the length of resection.