A. De Salles

The Side-Effects and Complications of Posteroventral Pallidotomy

The side-effects and complications of posteroventral pallidotomy are analysed in 138 consecutive patients who underwent 152 pallidotomies. Transient side-effects, lasting less than three months, appeared in 18% of the patients, that is, 16.5% of the surgical procedures. Long term complications, lasting more than 6 months, were noted in 10% of the patients, that is, 9.2% of the surgical procedures. Sixteen complications occurred alone or in various combinations in 14 patients and included fatigue and sleepiness (2), worsening of memory (4), depression (1), aphonia (1), dysarthria (3), scotoma (1), slight facial and leg paresis (2) and delayed stroke (2). Complications such as dysarthria and paresis could be attributed to MR- or CT-verified pallidal lesions lying too medially and encroaching on the internal capsule. Two of the patients with deterioration in memory had some memory impairment before surgery, and the aphonic patient had dysphonia preoperatively. The study suggests that stereotactic MRI and careful impedance monitoring and macro-stimulation of the posteroventral pallidum area should be sufficient for minimizing the risk of complications; the stereotactic lesion should be centered within the posterior ventral pallidum without involvement of internal capsule. It is concluded that pallidotomy is a safe procedure if performed on cognitively alert patients, and it seems that both the incidence and especially the severity of complications are lower for posteroventral pallidotomy than for thalamotomy.

Noninvasive linear accelerator radiosurgery as the primary treatment for trigeminal neuralgia

The application of a dedicated linear accelerator (DLINAC) as a noninvasive surgical treatment for trigeminal neuralgia has not yet been demonstrated. This work evaluates the outcome and indications of 22 patients submitted to DLINAC radiosurgery as a primary treatment for essential trigeminal neuralgia. At last follow-up evaluation, 21 patients (95.5%) had sustained significant pain relief. DLINAC radiosurgery is safe and effective as a primary noninvasive surgical treatment for selected patients with essential trigeminal neuralgia.

A Universal, Multi-Modality Localization System for Animal Radiosurgery

We have developed a stereotactic localization system allowing a radiosurgical approach in a number of animal models. The system utilizes fixation adapters specially designed for a particular animal, which in turn are attached to a common Brown-Roberts-Wells (BRW) compatible Delrin head ring. Each fixation adapter is constructed using materials compatible with CT, MRI, PET, and angiographic imaging studies. With such a system, radiographic localization, computerized treatment planning, and stereotactic radiation delivery can subsequently be performed in a manner identical to the procedures used for humans.

Radiofrequency ablation of brain tumours using MR guidance

SummaryMR-guided stereotactic thermal ablation was developed as a minimally invasive brain tumour treatment. Eighteen primary or metastatic brain tumours were treated in 15 patients. The entire procedure was performed under local anaesthesia in an MR suite. The outcome was analysed with 13-30 months of clinical follow-up. Local control was achieved in nine tumours in eight patients. Among them four patients with five tumours were disease-free for more than 22 months after the treatment. Four patients died from systemic disease or primary cancer while metastatic brain tumours were locally controlled. Local recurrence was seen in hypervascular metastatic tumours and a glioblastoma multiforme. For metastatic and primary brain tumours, MR provides not only accurate localization of brain tumour but also near real time thermal monitoring of acute tissue changes. This immediate imaging feedback facilitates safe and complete coagulation of the brain tumour. Based on our limited sample experiences, it is hoped tha...

Preliminary Novalis Experience in the Treatment of Skull Base Chordomas with StereotacticRadiosurgery and Stereotactic Radiotherapy

Purpose: The treatment of chordomas is challenging. The role of radiation therapy in addition to surgery is well established. Different techniques have been applied aiming to improve tumor local contr

Long-Term Follow-Up Using Linac Radiosurgery and Stereotactic Radiotherapy as a Minimally Invasive Treatment for Intracranial Meningiomas

Purpose: Report of technical aspects, results and strategies of stereotactic radiosurgery (SRS) and stereotactic radiation therapy (SRT) for treatment of intracranial meningiomas. Methods: A retrospective review of intracranial meningiomas treated at UCLA from May 1991 to July 2003 was performed with emphasis on technical aspects, radiological and clinical results. 161 patients with intracranial meningiomas treated by linear accelerator (Linac) stereotactic radiation were identified. There were 33 meningiomas in 32 patients with follow-up more than 48 months. Mean patient age was 57.2 years (range 19–87). There were 25 females and 7 males. 21 patients had surgical resection prior to radiosurgery. Stereotactic radiation was the primary treatment in 12 patients. Single dose radiation to 26 lesions and 7 were treated with fractionated technique. SRS dose prescribed to the periphery of the tumor ranged from 12 to 22 Gy (mean 15 Gy), SRT dose ranged from 23 to 54 Gy (mean 48 Gy). The prescription isodose ranged from 50 to 90% for the single dose group and from 85 to 90% for the fractionated treatments. Results: Follow-up was available for 32 patients treated between 48 and 125 months (mean 72.5). Tumor growth control was achieved in 30 benign meningiomas treated with SRS (92.3%) and in 7 benign meningiomas treated with SRT (100%). Worsening of previous neurological deficit was identified in 2 patients (7.9%) treated with SRS. No complications were found in SRT patients. Conclusion: Radiosurgery has been an alternative to surgical resection of selected intracranial meningiomas. Patients with tumors not amenable to either surgery or radiosurgery are now candidates for a less invasive technique than conventional radiotherapy. The need for total/subtotal surgical resection of these tumors is being challenged by superior imaging capabilities that allow for precise and effective stereotactic radiotherapy.