Lena S. Masri

Temporary occlusion of the middle cerebral artery in intracranial aneurysm surgery: time limitation and advantage of brain protection

The risk of focal infarction secondary to the induced reversible arrest of local arterial flow during microsurgical dissection of middle cerebral artery (MCA) aneurysms was evaluated further to define the optimal approach to temporary arterial occlusion. To compare the effectiveness of brain-protection anesthetics, a group of patients treated with the intravenous agents, propofol, etomidate, and pentobarbital, administered individually or in combination, was compared to a group treated with the inhalational agent isoflurane. Forty-nine consecutive MCA aneurysm surgeries involving the temporary clipping of the parent vessel were retrospectively reviewed. Thirty-eight patients received intravenous brain-protection (IVBP) anesthesia. Groups of patients with and without infarctions, and receiving and not receiving IVBP, were compared based on the duration and nature of temporary arterial occlusion. Postoperative radiographic evidence of new infarction was used as the threshold for failure of occlusion tolerance. The overall infarction rate was 22.4% (11 of 49 patients), including 15.8% (six of 38 patients) in the IVBP group versus 45.5% (five of 11 patients) in the isoflurane (ISO) group. In the ISO group, the mean duration of temporary occlusion was 3.9 +/- 2.2 minutes for patients without infarction versus 12.2 +/- 4.3 minutes for patients with focal infarction (p < 0.01). In contrast, the mean duration was 13.6 +/- 10.6 minutes for patients without infarction and 18.5 +/- 9.9 minutes for patients with infarction in the IVBP group. All patients in the ISO group who underwent occlusion lasting 10 minutes or longer suffered an infarction versus five of 23 patients in the IVBP group. Patients with multiple aneurysms were found to be at increased risk of developing focal infarction, whereas those treated with intermittent temporary clip application were at a decreased risk. It is concluded that patients in whom focal iatrogenic ischemia is induced during MCA aneurysm clip ligation have a significant advantage compared with those receiving ISO when they are given pentobarbital as the primary neuroprotective agent or when they receive propofol or etomidate titrated to achieve electroencephalographic burst suppression, particularly if more than 10 minutes of occlusion time is required. It is also concluded that 10 minutes is a general guideline for safe, temporary occlusion of the MCA. The use of intermittent temporary arterial occlusion and patients with multiple aneurysms need further evaluation before specific recommendations can be made.

Gamma Knife Radiosurgery for Metastatic Melanoma: An Analysis of Survival, Outcome, and Complications

OBJECTIVE Although the mainstays for treatment of metastatic brain disease have been surgery and/or external beam radiation therapy, an increasing number of patients are being referred for stereotactic radiosurgery as the primary intervention for their intracranial pathological abnormalities. The lack of efficacy and cognitive and behavioral consequences of whole brain irradiation have prompted clinicians to select patients for alternative therapies. This study analyzes the effectiveness of Leksell gamma unit therapy for metastatic melanoma to the brain. METHODS We present our experience with 59 Leksell gamma unit treatment sessions in 45 consecutive patients who presented with metastatic melanoma to the brain. Five of these procedures were performed as salvage therapy for patients who needed second radiosurgical treatment for new lesions that were remote from the previous targets and were not included in the overall analyses. RESULTS The population included 78% male patients. The mean patient age was 53 years (age range, 24-80 yr). The mean time from diagnosis of primary melanoma to discovery of brain metastasis was 43 months (median, 27.5 mo; range, 1-180 mo). At the time of diagnosis of brain disease, 35.5% of the patients (16 of 45 patients) had neurological symptoms, 77.7% (35 of 45 patients) had known visceral metastases, and 11.1% (5 of 45 patients) had seizure disorders. Eighty-six percent of the lesions (80 of 93 lesions) were cortical, 12% (11 of 93 lesions) were cerebellar, 1% (1 of 93 lesions) were pontine, and 1% (1 of 93 lesions) were thalamic. Fifty-seven percent of the sessions (31 of 54 sessions) were performed for a single lesion, 24.1% (13 of 54 sessions) for two lesions, 9.2% (5 of 54 sessions) for three lesions, 7.4% (4 of 54 sessions) for four lesions, and 1.8% (1 of 54 sessions) for five lesions. The mean treatment volume was 5.6 cc, with a mean prescription of 21.6 Gy to the 56.0% mean isodose line. The median survival time of the patients in our population, using Kaplan-Meier curves, was 43 months from the time of diagnosis of primary melanoma (range, 3-180 mo) and 8 months (range, 1-20 mo) from the time of gamma knife treatment. Complications included seizures within 24 hours of the procedure in four patients, with transient nausea and vomiting in three patients, transient worsening of preprocedure paresis responsive to steroids in three patients, and increased confusion in one patient. All 45 patients were located for follow-up (mean follow-up duration, 1 yr). After gamma knife treatment, 78% of the patients (35 of 45 patients) experienced either improved or stable neurological symptomatology before death or at the time of the latest follow-up examination. There were 26 deaths (58%). The cause of death was determined to be neurological in only 2 of 45 patients (7.7%). Follow-up magnetic resonance images revealed a 97% local tumor control rate of gamma knife-treated lesions, with 28% radiographic disappearance (9 of 32 cases). Six patients developed new lesions remote from radiosurgical targets and underwent second procedures. CONCLUSION Although metastatic melanoma to the brain continues to have a foreboding prognosis for long-term survival, gamma knife radiosurgery seems to be a relatively safe, noninvasive, palliative therapy, halting or reversing neurological progression in 77.8% of treated patients (35 of 45 patients). The survival rate matches or exceeds those previously reported for surgery and other forms of radiotherapy. Only 7.7% of the patients in our study population who died as a result of metastatic melanoma (2 of 26 patients) died as a result of neurological disease. The routine use of therapeutic level antiseizure medication is emphasized, considering the findings of our review.

Outcome For Preterm Infants with Germinal Matrix Hemorrhage and Progressive Hydrocephalus

OBJECTIVE An analysis of 76 preterm infants with Grade III or IV intracranial hemorrhage and surgically treated progressive hydrocephalus was undertaken to determine mortality, intellectual impairment, and motor deficit. METHODS The variables examined were degree of prematurity, birth weight, sex, Apgar scores, extent of intracranial hemorrhage, seizures, age at time of initial placement of a ventricular catheter reservoir to control hydrocephalus, need to convert the reservoir to a ventriculoperitoneal shunt, timing of the conversion of the reservoir to a ventriculoperitoneal shunt, and number of shunt revisions. Outcome was assessed for statistical significance using hierarchical linear regression and logistic regression analyses. RESULTS Linear regression analysis determined that mortality was best predicted, in order of importance, by extent of intracranial hemorrhage, number of shunt revisions, and birth weight (P < 0.0001, R = 0.79). Grade of hemorrhage, weight at birth, and presence of seizure activity were the most important determinants of motor outcome (P < 0.001, R = -0.78). CONCLUSIONS Logistic regression analysis of the 41 long-term survivors determined that grade of hemorrhage was the most important variable in determining cognitive outcome (P < 0.0001), motor function (P < 0.0001), and presence of seizure activity (P < 0.001). A logistic model of survival determined that grade of hemorrhage and multiple shunt revisions (more than five) were the most important determinants (P < 0.0001) of survival. In conclusion, the overwhelming factor in determining outcome in this patient group was the extent of intracranial hemorrhage.

Outcome Prediction after Penetrating Craniocerebral Injury in a Civilian Population

In an attempt to evaluate the response of patients who have low admission Glasgow Coma Scale scores (GCS) after a penetrating craniocerebral injury to aggressive management, we evaluated a series of 190 patients with penetrating injuries who presented with a GCS score of 3, 4, or 5 during a 6-year period. Entrance criteria required replicable neurological examinations that were not altered by the presence of hypotension, drugs/toxins, or systemic injury. The surgical patients included 21 patients with an admission GCS score of 3, 24 with an admission GCS score of 4, and 15 with an admission GCS score of 5. All patients underwent surgical intervention and aggressive perioperative management in the neurosurgical intensive care, including resuscitative protocols. Five of the patients with a GCS score of 3 survived, all with poor outcomes. Seven of the patients with a GCS score of 4 survived, although only one had a good outcome. Eleven of the patients with a GCS score of 5 survived. Five had a Glasgow Outcome Score of 2, five had a Glasgow Outcome Score of 3, and one had a Glasgow Outcome Score of 4. We have devised a prospective model of outcome based on our series in an attempt to predict nonsurvivors at admission (while overpredicting for survivors). The variables most predictive of mortality include admission GCS score and subarachnoid hemorrhage in one model and admission GCS score and pupillary changes in a second, when pupillary response was definitive at admission (P < or = 0.00005).(ABSTRACT TRUNCATED AT 250 WORDS)

Gradient of pressure and time between proximal anal canal and high-pressure zone during internal anal sphincter relaxation: Its role in the fecal continence mechanism

PURPOSE: The normal response to rectal distention is a relaxation of the proximal anal canal (PAC). We hypothesized that this mechanism would require a gradient of pressure and time to preserve continence. METHODS: Sixteen volunteers (10 male), mean age, 41.5 (range, 24–60) years, were studied using an eight port axial catheter with a compliant balloon at its tip. Relaxation was induced by a small volume of rectal distention (15–30 ml of air) and was recorded until recovery of resting anal pressure (RAP). Duration of relaxation was measured until recovery of RAP. Amplitude of relaxation was determined between RAP before rectal distention (RAP-BR) and pressure at the point of maximum relaxation (RAP-PMR). Gradient of pressure was determined by comparing RAP-PMR in the high-pressure zone (HPZ) and PAC. Contraction in the distal anal canal was interpreted as external anal sphincter contraction (EASC) and was compared with RAP-PMR in the HPZ. RESULTS: Relaxation was significantly greater in PAC than in HPZ (50vs. 36 percent;P=0.001). RAP-PMR was significantly higher in HPZ than in PAC (30.7vs. 12.6 mmHg;P= 0.001). EASC was observed in six patients and did not show significant difference with RAP-PMR in HPZ (39.7vs. 36.3 mmHg; not significant). Relaxation began at the same time in all levels but lasted significantly longer in PAC compared with HPZ (13.5vs. 9.4 sec;P=0.003). CONCLUSION: Anal relaxation induced by small volume rectal distention involves a gradient in the pressure and time of relaxation between PAC and the HPZ.

Gunshot wounds to the head: gang- and non-gang-related injuries and outcomes

Primary objective: This study examined the differences between gang and non-gang-related incidents of penetrative missile injuries in terms of demographics, motivation, intra-cranial pathology, transit time, injury time and clinical outcome. Research design: Retrospective and prospective chart review. Methods and procedures: Between 1985–1992, 349 patients with penetrating missile injuries to the brain presenting to LAC-USC were studied. Experimental interventions: Inclusion criteria were implemented to keep the cohort as homogenous as possible. Patients excluded were those with multiple gunshot wounds, non-penetrating gunshot wounds to the head, systemic injuries and cases in which the motivation for the incident was unknown. Main outcomes and results: Gang-related shooting slightly out-numbered non-gang-related incidents. Demographic analysis showed both a male and Hispanic predominance for both gang- and non-gang-related victims and significant differences in gender, race and age. Occipital entrance sites were more common in the gang-related vs temporal entrance sites in the non-gang-related. Mean transit time to the emergency department for gang-related shootings was less than non-gang-related shootings (24.4 vs 27.8 minutes). Most shooting incidents took place between 6 pm and 3 am. No difference between survival and outcome was noted between gang and non-gang victims. Conclusions: Significant differences were found between gang- and non-gang-related shooting victims in terms of demographics, entrance site and transit time. No difference was found between injury time, survival and outcome between gang and non-gang populations.

Fecal diversion for penetrating colon injuries--still the established treatment.

PURPOSE: An analysis of the existing literature on primary repair of colon injuries was undertaken to determine if there is sufficient evidence that this approach is superior to fecal diversion. METHODS: After a thorough literature search, three prospectively randomized studies comparing primary repair with fecal diversion in the management of colon injuries were identified. A variety of factors were examined, including the number of patients in each study arm, morbidity rates, as well as exclusion criteria. An analysis was performed to determine the number of patients required to establish statistical superiority of one procedure over the other. RESULTS: Pooling of the data contained in the aforementioned reports does not provide sufficient statistical power to support the superiority of primary repair of colon injuries. To demonstrate a 5 percent difference between the two approaches, a prospective, randomized study consisting of 200 patients in each arm is necessary. CONCLUSION: The present literature does not support a statistically valid advantage of primary repair over fecal diversion in the management of traumatic colon injuries.