Jamal M. Taha

Outcome of unilateral and bilateral pallidotomy for Parkinson's disease: Patient assessment

OBJECTIVEnPallidotomy has recently regained acceptance as a safe and effective treatment for Parkinsons disease symptoms. The goal of this study was to obtain the patients perspective on their results after undergoing this procedure. Special attention was focused on the potential complications and the respective advantages and risks of unilateral versus bilateral pallidotomy.nnnMETHODSnFifty-six patients were studied during a 2-year period; 44 completed the evaluation, with a median follow-up of 7 months. Of these patients, 22 underwent unilateral pallidotomy, and 17 had bilateral simultaneous pallidotomy. Five patients who underwent staged bilateral pallidotomy were excluded from the statistical analysis, because the number of patients was considered too small for analysis. The procedures were performed with magnetic resonance imaging determination of the target, combined with physiological confirmation, including microelectrode recording.nnnRESULTSnAccording to Visual Analog Scale scores, unilateral pallidotomy significantly improved dyskinesias (P < 0.05) but no other symptoms. Simultaneous bilateral pallidotomy improved slowness, rigidity, tremor, and dyskinesias (P < 0.05) but worsened speech function (P < 0.05). According to the patients most frequently chosen answers to multiple-choice questions, unilateral pallidotomy improved night sleep, muscle pain, freezing, overall on, overall off, and the duration of off periods, but it worsened the volume of the voice and articulation, increased drooling, and reduced concentration. Bilateral pallidotomy improved night sleep, muscle pain, freezing, overall on, overall off, duration of off periods, and the amount of medication taken, but it increased drooling and worsened the volume of the voice, articulation, and writing. Subjective visual disturbance was noted in 36 and 41% of patients who underwent unilateral and simultaneous bilateral pallidotomy, respectively. Globally, the result of the procedure was rated good or excellent by 64% of the patients who underwent unilateral pallidotomy and by 76% of the patients who underwent bilateral pallidotomy. An age less than 70 years was a positive prognostic factor for the global outcome (P < 0.05), as were severe preoperative dyskinesias (P < 0.05).nnnCONCLUSIONnThis study confirms that, from a patient standpoint, unilateral and simultaneous bilateral pallidotomy can reduce all the key symptoms of Parkinsons disease (i.e., akinesia, tremor, and rigidity) and the side effects of L-dopa treatment (i.e., dyskinesias). Preoperative severe dyskinesias and younger age are positive prognostic factors for a successful outcome. Simultaneous bilateral pallidotomy was more effective than unilateral pallidotomy regarding tremor, rigidity, and dyskinesias, but it conferred a higher risk of postoperative speech deterioration.

Intracranial infection after missile injuries to the brain: report of 30 cases from the Lebanese conflict.

This study reviews the features of 30 intracranial infections complicating 600 penetrating head injuries from missiles in patients treated at the American University of Beirut Medical Center between 1981 and 1988. The follow-up period ranged from 1 month to 7 years (mean, 2.5 years). Sixteen patients had a brain abscess, 9 had cerebritis, 2 had an infected intracerebral hematoma, and 5 had meningitis. Infection developed 4 days to 7 years after the initial debridement. The infecting organisms were Gram positive in 11 patients (36%), Gram negative in 12 (40%), and a combination of Gram positive and Gram negative in 2 (7%). Twenty-four patients (80%) had wound dehiscence or cerebrospinal fluid leakage at the time the infection appeared. There was a 76% correlation between the organisms cultured from the dehiscent scalp wound and the brain. Twenty-three patients had intracranial retention of bone. Infection developed in 16 of the 30 patients (70%) around bone fragments, in 4 around a metallic fragment, in 2 around absorbable gelatin sponge, and in 3 along the missile tract; 2 had an infected intracerebral hematoma, and 3 had meningitis. At least one of the following risk factors was present in each patient: extensive brain injury, coma, trajectory through an air sinus, cerebrospinal fluid fistula, inadequate initial debridement, or incomplete dural closure. The incidence of intracranial infection in patients with postoperative retention of bone was 4% in the absence of scalp wound dehiscence, compared with 84.6% when wound dehiscence was present. Ten patients (43%) still retained a bone fragment measuring less than 1 cm after excision of a brain abscess or treatment of cerebritis or meningitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Missile Injuries to the Brain Treated by Simple Wound Closure: Results of a Protocol during the Lebanese Conflict

This is a prospective study of the treatment of penetrating missile injuries to the brain without intracranial surgery carried out at the American University of Beirut Medical Center between 1981 and 1988. Of 600 patients treated for missile injuries to the head, 32 satisfied the study criteria. There were 27 shrapnel and 5 bullet injuries. The mean patient age was 23 years (range, 3-51 years). Twenty patients had intracranial indriven bone fragments. Six patients had exposed brain tissue. The mean follow-up was 3.5 years (range, 1-7.5 years). The superficial entry wound was debrided and closed without drainage in the Emergency Room within a mean of 3 hours (range, 0.5-6 hours), and the patient received methicillin for 14 days. All patients survived and had no or improved neurological deficits. No leakage of the cerebrospinal fluid, infection, or seizures occurred in 31 patients. One patient with indriven bone fragments had leakage of the cerebrospinal fluid and developed seizures and a brain abscess 20 days after the injury. The management of penetrating missile injuries to the brain without intracranial surgery in a select patient population is a reasonable option. This treatment becomes important for a surgeon facing large numbers of casualties, or when operative personnel or resources are limited or unavailable.

Computer analysis of the tonic, phasic, and kinesthetic activity of pallidal discharges in parkinson patients

OBJECTIVEnIntraoperative analysis of microrecording data during pallidotomy often depends on subjective interpretation of the oscilloscope signal, especially during the analysis of phasic activity. The goals of this project were: 1) to develop an inexpensive system that allowed on-line, objective characterization of single-unit pallidal discharges, and 2) to have objective criteria to differentiate the internal part (GPi) from the external part (GPe) of the globus pallidus.nnnMETHODSnA computer program was developed that allowed the analysis of firing rates (mean, median, and quartiles), spike count per unit time, and interspike interval (ISI) histograms with Chi-square statistical evaluation. Indices were developed that measured phasic activity, including burst index (BI) for the measurement of bursts, pause index (PI) for the measurement of pauses, and pause ratio (PR) for analysis of time spent in pauses. Single-unit activity of 152 GPe and 203 GPi cells in 47 Parkinson patients were digitized using the computer soundcard during pallidotomy and analyzed using this software.nnnRESULTSnGPe discharges had a mean firing rate = 42 Hz, BI = 0.81, PI = 0.21, and PR = 1.41. GPi had a mean firing rate = 81, BI = 1.61, PI = 0.04, and PR = 0.21. The PR was the best index that differentiated GPe from GPi, followed by PI, BI, and firing rates, in that order. Kinesthetic cells were recorded equally in GPe from GPi, and their responses to generalized movements were not significantly different.nnnCONCLUSIONn(1) Signal analysis using the digitization process of a computer sound card and dedicated software is satisfactory for the objective on-line and off-line analysis of microrecordings (including phasic activity); (2) PI and PR are most helpful in differentiating neurons of GPi from those of GPe; (3) no single parameter can differentiate GPe from GPi activity in all cases; and (4) unlike the findings in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys, GPe and GPi of Parkinson patients have similar prevalence of kinesthetic cells and similar responses to generalized somatotopic effects.

A Method to Reduce Systematic Spatial Shift Associated with Magnetic Resonance Imaging

To reduce the chemical shifts during magnetic resonance (MR) imaging, the authors replaced the petroleum gel in the Brown-Roberts-Well (BRW) MR localizer with chromium chloride. Computed tomography and MR scans were obtained of a phantom skull containing objects with known spatial coordinates. A 2-to 3-mm systematic spatial shift in the frequency-encoded direction was observed with petroleum gel, but not with CrCl3. Results were verified by reconstructing the three-dimensional spatial location of each object using X-Knife computer software. The authors conclude that spatial localization is more accurate with a CrCl3-filled than a petroleum-filled BRW-MR localizer.

Infrequent Types of Pallidal Discharges during Pallidotomy

Pallidal discharges of patients with Parkinsons disease have been characterized as slow irregular or bursting discharges for the external pallidal segment (GPe) and fast discharges for the internal pallidal segment (GPi). Tremor-synchronous cells have also been described. Using microrecording techniques on 70 patients who underwent pallidotomy, we have recorded other types of pallidal discharges. In GPe, we recorded cells which fired fast, cells which were silent, and cells which fired tonically. In GPi, we recorded cells which burst following short segments of fast tonic discharges. We will demonstrate these cells and discuss their clinical significance.

Early detection of postoperative residual tumor using image subtraction

The detection after surgery of residual tumor from magnetic resonance (MR) images is difficult due to the low contrast level of the images. Gadolinium-enhanced MR imaging has been found valuable in detecting residual enhancing tumor when performed within 72 hours after surgery. The patient is scanned by the MR scanner with and without infusion of gadolinium, a contrast agent. Usually, the estimation of post-operative tumor volume is done by visual comparison of the T1 MR images obtained with and without gadolinium infusion. The T1 MR images, in most cases, without contrast demonstrates areas of hyper intensities (high brightness levels), consistent with hemorrhage. These hyper intense areas often make it difficult to detect residual tumor in post contrast images. This is due to the presence of both acute hemorrhage and gadolinium enhancement which have high brightness levels in T1 MR images. Even in MR images taken within 72 hours after surgery, detection of tumor enhancement in areas of increased T1 signal produced by blood products or by postoperative changes can be difficult when performed by the naked eye. Due to these problems, the quantification of residual tumor becomes a subjective issue among neuro-radiologists. Thus to reduce errors produced by the human factor, an automated procedure to detect residual tumor is required. We have developed a technique to differentiate tumor enhancement from postoperative changes and blood products on MR imaging. The technique involves fusion of pre- and post-gadolinium MR images performed in the immediate postoperative period. Computerized slice based substraction is then done on the corresponding fused images of the two sets. The subtraction process results in a composite slice, which is examined for differences between pre- and post-gadolinium studies. The presented technique was tested on 14 cases in which MR images were obtained from brain tumor patients within 72 hours after surgery. The subtraction technique easily distinguished residual enhancing tumor from postoperative surgical changes and was simple to perform. The technique proposed and developed has given good results and will be used in clinical trial and diagnosis. Future potentials of the technique are discussed and illustrative cases presented.