Faculty Bibliography

Patients with temporal lobe epilepsy (TLE) often show increased cardiovascular sympathetic modulation during the interictal period, that decreases after epilepsy surgery. In this study, we evaluated whether temporal lobectomy changes autonomic modulation of cerebral blood flow velocity (CBFV) and cerebral autoregulation. We studied 16 TLE patients 3-4 months before and after surgery. We monitored heart rate (HR), blood pressure (BP), respiration, transcutaneous oxygen saturation (sat-O(2)), end-expiratory carbon dioxide partial pressure (pCO(2)) and middle cerebral artery CBFV. Spectral analysis was used to determine sympathetic and parasympathetic modulation of HR, BP and CBFV as powers of signal oscillations in the low frequency (LF) ranges from 0.04-0.15Hz (LF-power) and in the high frequency ranges from (HF) 0.15-0.5Hz (HF-power). LF-transfer function gain and phase shift between BP and CBFV were calculated as parameters of cerebral autoregulation. After surgery, HR, BP(mean), CBFV(mean), respiration, sat-O(2), pCO(2) and HF powers remained unchanged. LF-powers of HR, BP, CBFV and LF-transfer function gain had decreased while the phase angle had increased (p<0.05). The reduction of LF powers and LF-gain and the higher phase angle showed reduced sympathetic modulation and improved cerebral autoregulation. The enhanced cerebrovascular stability after surgery may improve autonomic balance in epilepsy patients

We present our experience with the use of dexmedetomidine, an alpha2 agonist, in two children undergoing awake craniotomy. General anesthesia with the laryngeal mask airway was used for parts of the procedure not requiring patient cooperation to reduce the duration of wakefulness and abolish the discomfort of surgical stimulation. Dexmedetomidine was used as a primary anesthetic for brain mapping of the cortical speech area. The asleep-awake-sleep technique provided adequate sedation and analgesia throughout the surgery and allowed the patient to complete the necessary neuropsychological tests. To our knowledge, ours is the first description of the use of dexmedetomidine in pediatric neurosurgery

In patients with mesiotemporal sclerosis, posterior hippocampal involvement at the ictal onset is not associated with an excellent outcome. A study confirmed that ictal onset in the posterior parahippocampal gyrus is associated with a less favorable outcome compared with ictal onset in the anterior parahippocampal gyrus in patients with mesiobasal temporal lobe epilepsy who are undergoing foramen ovale recording. The authors hypothesized that involvement of the two medial contact points of posterior basal temporal subdural (SD) strip at the ictal onset, representing ictal onset in the posterior parahippocampal gyrus, may also adversely influence the surgical outcome. With this objective, the authors assessed the incidence of posterior basal temporal SD strip (the two medial contact points) involvement at the ictal onset in patients with mesiotemporal sclerosis and determined whether presence of this finding influenced surgical outcome. Thirty-six patients with mesiotemporal sclerosis underwent a single SD grid (lateral frontotemporal) and strips (three basal temporal and one orbitosubfrontal) monitoring. Based on the earliest involvement of basal temporal strips (the two medial contact points) during the seizure, patients were classified into (1) anterior and/or middle basal temporal, or (2) posterior basal temporal (with or without involvement of anterior and/or middle basal temporal) ictal onset groups. A temporal lobectomy with adequate resection of the ictal onset zone was performed in all patients. Surgical outcome was based on Engel's classification. Six of 36 (17%) patients were classified into the posterior basal temporal ictal onset group. Only two patients from the posterior basal temporal ictal onset group experienced a good outcome compared with 26 of 30 patients from anterior and/or middle basal temporal ictal onset group (P = 0.01). In patients with mesiotemporal sclerosis who were monitored with SD electrodes, involvement of the two medial contact points of posterior basal temporal strip at the ictal onset (representing ictal onset in the posterior parahippocampal gyrus) occurred in 17% of the patients. These patients might not experience an excellent surgical outcome despite including the ictal onset zone in resection. These findings may be useful in presurgical counseling of patients with mesiotemporal sclerosis who undergo intracranial SD monitoring

PURPOSE: This report describes our long-term follow-up for combined resective surgery and multiple subpial transections (MSTs) in patients with refractory epilepsy involving eloquent and noneloquent cortex in multiple lobes. Multiple independent seizure foci made these patients poor candidates for conventional surgery. METHODS: MST and resective surgery were used in 13 patients to treat localization-related refractory epilepsy involving eloquent and noneloquent cortex of two or more lobes. Preoperative investigation was followed by invasive monitoring. RESULTS: Eleven patients had MST plus resection involving two different lobes, and two patients had MST plus resection involving three different lobes. MSTs were performed on the primary sensorimotor cortex (eight patients), temporal language area (two patients), Broca's area (one patient), and on both frontal motor and temporal language areas (two patients). Nine patients had a two-stage procedure, and four patients had a three-stage procedure (two consecutive subdural grid studies followed by resections). Average follow-up was 59.2 months (range, 42-98 months). With a modified Engel Outcome Scale, four patients (31%) had a class I outcome; three (23%), class II; three (23%), class III; and three (23%), class IV. Ten (77%) patients had a >50% reduction of seizure burden. CONCLUSIONS: Combined MST and resection can meaningfully improve seizure control in patients with multifocal epilepsy involving eloquent cortex. Prospective randomized studies are needed

In temporal lobe epilepsy (TLE), there is evidence of ictal and interictal autonomic dysregulation, predominantly with sympathetic overactivity. The effects of TLE surgery on autonomic cardiovascular control and on baroreflex sensitivity (BRS) have not been studied. To evaluate such effects, we monitored heart rate (HR), systolic blood pressure (BP(sys)) and respiration in 18 TLE patients 3-4 months before and after TLE surgery. We used Blackman-Tukey spectral analysis to assess sympathetic and parasympathetic modulation as powers of HR and BP(sys) oscillations in the low frequency (LF, 0.04-0.15 Hz) and high frequency (HF, 0.15-0.5 Hz) bands. BRS was determined as the LF transfer function gain between BP and HR. After surgery, HR, BP(sys), respiration and HF powers remained unchanged, while LF powers of HR (1.57 +/- 1.54 bpm(2)) and BP(sys) (2.19 +/- 1.34 mmHg(2)) and BRS (0.68 +/- 0.31 bpm/mmHg) were smaller than pre-surgical LF powers of HR (3.87 +/- 3.26 bpm(2)) and BP(sys) (4.80 +/- 3.84 mmHg(2)) and BRS (1.12 +/- 0.39 bpm/mmHg; P < 0.05). After TLE surgery, there is a reduction of sympathetic cardiovascular modulation and BRS that might result from decreased influences of interictal epileptogenic discharges on brain areas involved in cardiovascular autonomic control. TLE surgery seems to stabilize the cardiovascular control in epilepsy patients by reducing the risk of sympathetically mediated tachyarrhythmias and excessive bradycardiac counter-regulation, both of which might be relevant for the pathophysiology of sudden unexpected death in epilepsy patients (SUDEP). Thus, TLE surgery might contribute to reducing the risk of SUDEP

We studied long-term outcome (range, 28-89 months; mean, 56 months) after multiple subpial transections (MSTs) for medically refractory epilepsy. Forty-three (79.6%) of 54 patients had a consistent significant reduction in seizure frequency, and 27 (50%) of the 54 were either entirely seizure free or virtually so. However, 10 (18.6%) patients sustained an increase in seizure frequency several years after surgery, after showing initial postoperative improvement. This suggests that late seizure recurrence is a more important problem in cases in which MST has been performed than for pure resections

We studied long-term outcome (range, 28-89 months; mean, 56 months) after multiple subpial transections (MST) for medically refractory epilepsy. Forty-three (79.6%) of 54 patients had a consistent significant reduction in seizure frequency, and 27 (50%) of the 54 were either entirely seizure free or virtually so. However, 10 (18.5%) patients sustained an increase in seizure frequency several years after surgery, after showing initial postoperative improvement. This suggests that late seizure recurrence is a more important problem in cases in which MST has been performed than for pure resections

OBJECTIVE: Indwelling intrathecal drug delivery systems are becoming increasingly important as a method of neuromodulation within the nervous system. In particular, intrathecal baclofen therapy has shown efficacy and safety in the management of spasticity and dystonia in children. The most common complications leading to explantation of the pumps are skin breakdown and infection at the pump implantation site. The pediatric population poses particular challenges with regard to these complications because appropriate candidates for intrathecal baclofen therapy are often undernourished and thus have a dearth of soft tissue mass to cover a subcutaneously implanted baclofen pump. We report a technique of subfascial implantation that provides greater soft tissue coverage of the pump, thereby reducing the potential for skin breakdown and improving the cosmetic appearance of the implantation site. METHODS: Eighteen consecutively treated children (average age, 8 yr, 7 mo) with spasticity and/or dystonia underwent subfascial implantation of a baclofen pump. These children's mean weight of 42.9 lb is less than the expected weight for a group of children in this age group, ranging from 4 years, 8 months, to 15 years, 7 months. In all patients, the pump was inserted into a pocket surgically constructed between the rectus abdominus and the external oblique muscles and the respective anterior fascial layers. RESULTS: At an average follow-up of 13.7 months, no infection or skin breakdown had occurred at the pump surgical site in any of the 18 patients. CONCLUSION: At this early follow-up, the subfascial implantation technique was associated with a reduced rate of local wound and pump infections and provided optimal cosmetic results as compared with that observed in retrospective cases