Anterior Callosotomy Research Articles

The surgical effect of callosotomy in the treatment of intractable seizure.

We evaluated the surgical effects of the callosotomy, particularly with respect to the effect of callosotomy in some seizure types and the extent of surgery. Twenty-one patients with a minimum follow-up of two year were enrolled. The most significant effect of callosotomy was the complete suppression of the generalized seizures associated with drop attack in 12 of 21 patients and seizure reduction of more than 75% in 6 of 21 patients. The surgical effect on the partial seizures was very variable. Transient disconnection syndrome appeared in 4 patients after anterior callosotomy. Total callosotomy by staged operation significantly suppressed generalized seizures associated with drop attack without any disconnection syndrome. Our data show that callosotomy is quite a good approach to the surgical treatment of drop attacks accompanied by disabling generalized seizures.

Surgical strategy for distal anterior cerebral artery aneurysms: microsurgical anatomy.

Most distal anterior cerebral artery (ACA) aneurysms arise at the pericallosal-callosomarginal artery (PerA-CMA) junction, which is usually located in the A3 segment of the ACA around the genu of the corpus callosum. Aneurysms in the PerA-CMA junction are divided into two types according to their location: supracallosal and infracallosal. Infracallosal distal ACA aneurysms are defined as those located in the lower half of the A3 segment, which makes it more difficult to gain proximal control. In this study, the authors examined the microsurgical anatomy of the distal ACA region, focusing especially on the relationship between the PerA and CMA located in the lower half of the A3 (infracallosal) segment, and present a surgical strategy for dealing with distal ACA aneurysms. The microsurgical anatomy of the distal ACA region was examined in 22 adult cadaveric cerebral hemispheres after perfusion of the arteries and veins with colored silicone. The relationships of the infracallosal segment of the PerA to the CMA and the A2 segment of the PerA to the frontopolar artery were examined. The distance between the nasion and the site at which a parallel line directed along the long axis of the infracallosal PerA just proximal to the origin of the CMA artery crosses the forehead (which we have named the PC point) was also measured. Surgical approaches to distal ACA aneurysms were examined in stepwise dissections. The PerA-CMA junctions were located in the supracallosal and infracallosal segments of A3 in 36 and 55% of cases, respectively. In the infracallosal region, it was difficult to identify the proximal PerA and to establish proximal control of the vessel. The infracallosal part of the proximal PerA coursed almost parallel to the frontal cranial base, and the PC point was 42.2 +/- 15.9 mm (mean +/- standard deviation) from the nasion. These findings indicate that there is only a limited space in which to access an infracallosal distal ACA aneurysm below the PC point and establish proximal control by the anterior interhemispheric approach. When the approach is made above the PC point, an anterior callosotomy may be necessary to establish proximal control before final aneurysm dissection and clip placement are completed. The PC point is an important surgical landmark in planning the surgical strategy for infracallosal distal ACA aneurysms.

Callosal role in generation of epileptiform discharges: quantitative analysis of EEGs recorded in patients undergoing corpus callosotomy.

Corpus callosotomy tends to decrease seizure frequency and severity rather than transforming the seizure pattern from a generalized form into a lateralized or a partial one. The finding implies that bisection of the corpus callosum (CC) disrupts the epileptogenicity itself. In order to gain further insight into the possible role played by the CC in intractable generalized epilepsy, quantitative analyses of long-term EEGs were performed. Analyses were made of epileptiform discharges contained in the pre- and postoperative long-term EEGs in 7 patients who had an anterior callosotomy for intractable epilepsy. The duration, number, and amplitude of all epileptiform burst activities were measured and statistically analyzed. After callosotomy, the total number of epileptiform burst activities, mean duration, and the total number of spike discharges decreased significantly. The two hemispheres could be divided into dominant and non-dominant ones as to the quantity of the residual epileptiform discharges. Corpus callosotomy unevenly reduced preoperative epileptiform discharges in both hemispheres, suggesting a facilitatory role played by the callosal neurons that enables the asymmetrical epileptogenic susceptible state of the two hemispheres to develop bisynchronous and bisymmetrical epileptiform discharges. Corpus callosotomy decreased the quantity of the epileptiform discharges, suggesting the transhemispheric facilitation of seizure mechanisms.

Medically intractable, localization-related epilepsy with normal MRI: presurgical evaluation and surgical outcome in 43 patients.

High-resolution magnetic resonance imaging (MRI) plays a crucial role in the presurgical evaluation of patients with medically refractory partial epilepsy. Although MRI detects a morphologic abnormality as the cause of the epilepsy in the majority of patients, some patients have a normal MRI. This study was undertaken to explore the hypothesis that in patients with normal MRI, invasive monitoring can lead to localization of the seizure-onset zone and successful epilepsy surgery. A series of 115 patients with partial epilepsy who had undergone intracranial electrode evaluation (subdural strip, subdural grid, and/or depth electrodes) between February 1992 and February 1999 was analyzed retrospectively. Of these, 43 patients (37%) had a normal MRI. Invasive monitoring detected a focal seizure onset in 25 (58%) patients, multifocal seizure origin in 12 (28%) patients, and in six patients, no focal seizure origin was found. Of the 25 patients with a focal seizure origin, cortical resection was performed in 24, of whom 20 (83%) had a good surgical outcome with respect to seizure control. Six of the 12 patients with multifocal seizure origin underwent other forms of epilepsy surgery (palliative cortical resection in two, anterior callosotomy in two, and vagal nerve stimulator placement in two). Successful epilepsy surgery is possible in patients with normal MRIs, but appropriate presurgical evaluations are necessary. In patients with evidence of multifocal seizure origin during noninvasive evaluation, invasive monitoring should generally be avoided.

Seizure outcomes after anterior callosotomy in patients with posterior-dominant and with anterior-dominant epileptiform discharges.

We wished to find whether there was any difference in the postoperative seizure outcome between patients with bisynchronous anterior-dominant and those with posterior-dominant EDs after anterior callosotomy. Seizure outcomes after anterior callosotomy in 7 patients with bisynchronous posterior-dominant epileptiform discharges and in 54 patients with anterior-dominant seizures were compared. All 61 cases had been followed up for more than 2 years after operation. One patient (14.3%) had become seizure free. Two patients (28.6%) had more than 50% reduction in seizure frequency, but 4 patients (57.2%) showed no improvement at all. The percentage of cases with significant improvement (more than 50% reduction of seizure frequency) was 43% (3 in 7), which is lower than in the patients with bisynchronous anterior-dominant EDs (64.8%). Our preliminary results suggest that anterior partial callosotomy could still be helpful in cases with bisynchronous posterior-dominant epileptiform discharges but the prognosis may be less optimistic than for those with anteriorly located discharges.

Anterior Corpus Callosotomy in the Treatment of Medically Intractable Epilepsy: Multicenter Study in Japan

Purpose: Corpus callosotomy has been extensively used in the past 25 ycars Tor the treatment of patients with medically intractable epilepsy who do not qualify for resective surgery. However, several issues remain controversial; i.e., the criteria for patient selection, the timing of the operation, the extent of the callosal division, and the significance of postoperativc EEG changes. We report on the results of anterior corpus callosotomy (ACC) in 53 intractable seizure patients undertaken in a multiccnter analysis in Japan to define predictive outcome factors. Methods: 53 patients with more than I year postoperative follow‐up (mean 43.2 months) were included. Age at the time of operation ranged from 5 to 44 years (mean 19.9), and age at the onset of epilepsy ranged from 0.3 to 23 years (mean 6.3). Preoperative diagnoses were cryptogenic or symptomatic generalized epilepsy (SGE) (34 patients), frontal lobe epilepsy (FLE) (17 patients), and severe myoclonic epilepsy in infancy (2 patients). Seizure outcome at the time of the most recent follow‐up was classified into 5 classes: Free, with complete elimination of seizure; Excellent, with >SO% reduction in seizure frequency; Good, with >50% reduction in seizure frequency;: Poor, with no significant change; Worse, with worsening of seizures and / or unacceptable neurological deficit. The relationships between outcome and clinical factors such as epileptic syndrome, seizure type, age at surgery, age of onset, duration of epilepsy, preoperative IQ, extent of callosol division, and postoperative EEG changes were analyzed. Results: 36 of 53 patients (67.9%) showed significant improvement after the surgery. The outcome was seizure free in 4 (7.576), excellent in 18 (34.0%), good in 14 (26.4%), and poor in 17 patienfs (32.1%). There was no worse case, Four seizure‐free patients were included in pediatric group (under 15 years). 70.6% of the patients with SGE and 64.7% of those with FLE showed a significant improvement. In addition, 1 each of the 2 patients with SME showed a good and poor outcome, respectively. Significant improvement occurred in 70%‐80% of all the seizure types except for simple partial seizure (40.0%) andcomplex partial seizure (46.7%). Complete elimination of seizure was obtained in 38.1 % of drop attack, 33.3% of generalized tonic‐clonic seizure, 33.3% of myoclonic seizure. 30.0% of partial seizure with secondary generalization, and 27.8% of atypical absence. None of the clinical factors correlated significantly with the outcome cxcept for a shorter duration of epilepsy in the seizure free patients. A tzndency of a better outcome was observed in the pediatric group (p =0.093), when seizure onset was after age 1 (p=0.339), in those with a higher IQ (p = 0. I38), and when there was a disappearance or lateralizetion of thc slow spike and wave to the unilateral hemisphere on postoperative EEG (p = 0.159). There was no clear relationships between the extent of the callosal division and the outcome. Conclusion: The results suggest that ACC is most profitably performed during the early stage of illness, except in those patients with seizure onset before age 1 associated with severe brain dysfunction. Availability of a chronological developmental IQ during infancy and computer analysis of generalized epileptiform activity prior to surgery will likely improve the quality of case selection and therefore, the surgical outcome.

A 13-Year Experience with Epilepsy Surgery

Between 1985 and 1997, 563 therapeutic craniotomies were performed: 311 anterior temporal (ATL) and 158 extramesial temporal (XMT) resections, 67 callosotomies, 20 hemispherectomies and 7 multiple subpial transections. Sixty-seven percent of nonlesional ATL cases were seizure free (SF), and 76% of nonlesional ATL cases ≤18 years old were SF. Seventy-eight percent of lesional ATL cases with complete resection were SF. Seventy-three percent of lesional cases ≤18 were SF. Thirty-seven percent of nonlesional XMT cases were SF. Seventy percent of XMT lesional cases with complete resection were SF, and 82% of lesional XMT cases ≤18 were SF. Of the anterior callosotomy cases, there was a ≥90% decrease in generalized tonic-clonic seizures in 50% of patients, and in tonic seizures, drop attacks, absence and myoclonic seizures in approximately 60–70% of patients. Of 20 hemispherectomies, 65% were SF. Of 7 multiple subpial transections, 29% were SF.

Seizure outcome after corpus callosotomy: the Taiwan experience.

From September 1989 to August 1996, we performed anterior corpus callosotomy in 83 patients. Unfortunately, 9 patients were lost to follow-up. Among the remaining 74 patients, 59 had Lennox-Gastaut syndrome (evolved from infantile spasms in 22), 9 had complex partial seizures with or without secondary generalized seizures, 1 had multifocal independent epileptogenic foci (MISF) syndrome, 3 had hemiconvulsion-hemiplegia-epilepsy (HHE), and 2 had infantile spasms. All cases were followed up for at least 2 years after surgery. The highest rate of significant improvement (more than 50% reduction in seizure frequency) was noted in the patients with generalized tonic-clonic seizures, 82.1% of whom experienced significant improvement, followed by those with generalized tonic seizures (76. 7%), atonic seizures (72.7%), myoclonic seizures (64.9%), atypical absences (58.6%), and complex partial seizure with or without secondary generalization (61.5%). Complete freedom from seizures was noted in 14 cases (18.9%). One patient had the anterior half of his right palm amputated following radial artery thrombosis complicated by insertion of an arterial line during anesthesia. Otherwise, there were no major postoperative complications except for brief mutism and multifocal jerks in some patients during the 1st postoperative week. Thus, we conclude that corpus callosotomy is a safe alternative treatment for all kinds of medically intractable seizures, especially generalized epilepsy.

Divided visuo-spatial attention systems with total and anterior callosotomy

The role of the corpus callosum in the inter-hemispheric integration of the visuo-spatial attention system, was investigated in patients with a total callosotomy or with an anterior callosal section. Subjects produced simple reaction times (RTs) to visual targets shown to the left or right visual hemifield. Preceding the target by an interval of 500 ms, arrow cues predicting the target location were shown left and right of the point of ocular fixation. For a majority of total and anterior callosotomy patients, results with valid focused cues (both arrows pointing to the target location) and with divided-attention cues (arrows pointing away from fixation) did not differ and both conditions produced shorter RTs than with neutral cues (equal signs). In contrast, neurologically intact subjects showed equal RTs with divided-attention and neutral cues, whereas valid focused cues produced reduced RTs relative to neutral cues. These results indicate that most split-brains, in contrast to normal observers, are capable of directing their attention to left and right visual field locations simultaneously, and therefore that each cerebral hemisphere controls its own visuo-spatial attention mechanism.

Callosotomy for epilepsy after West syndrome.

To analyze the results of callosotomy in 17 children with symptomatic generalized epilepsy after West syndrome, according to the different seizure types and surgical procedures, to define selection criteria for candidates to callosotomy. Callosotomy was performed in two successive stages. Partial callosotomy, anterior in 13 and posterior in three, was followed by completion in 14 cases in all but four patients (complete callosotomy in one stage in one, no completion in three). All patients had clinical, video-EEG, and neuropsychological evaluation before and after each stage of callosotomy, with a mean final follow-up of 4 years. Seizure frequency improved in only two of 13 patients after anterior callosotomy, in none of three after posterior callosotomy, but in nine of 14 after complete callosotomy. After complete callosotomy, spasms disappeared in 80% of the cases, and drop attacks, the most severe ictal event, completely stopped or were dramatically reduced in 90% of the children. One patient no longer had episodes of status epilepticus, and another one acquired the ability to walk after complete callosotomy. From the cognitive viewpoint, nine patients with improved seizure frequency after complete callosotomy also had improved behavior and cognitive functions, but two others experienced speech deterioration after posterior callosotomy at age 11 years and completion of callosotomy at age 16 years. As in other severe generalized epilepsies in childhood, drop attacks provide the best indication for complete callosotomy in patients with previous West syndrome. Because drop attacks can be identifiable by falls only, the previous acquisition of walking should be considered as a key feature for any benefit to be obtained.

Direction information coordinated via the posterior third of the corpus callosum during bimanual movements.

We examined bimanual coordination in a patient before and after each stage of callosotomy surgery. We tested how well the patient coordinated movement direction between the hands. The patient drew symmetrical or asymmetrical figures simultaneously with both hands. Before surgery, symmetrical figures were drawn well and asymmetrical figures were drawn poorly. Following anterior callosotomy, the drawings improved slightly. Symmetrical figures were still drawn well, and asymmetrical ones were still drawn poorly. Thus, spatial integration remained intact despite the loss of interhemispheric communication between frontal cortical sites. After posterior callosotomy, spatial coordination deteriorated significantly. Mirror-image drawings became less symmetrical, while asymmetrical drawings improved. These data indicate that the posterior callosum mediates the coordination of direction information between the hands during bimanual movements. Given the topographical organization of the corpus callosum, this integration is likely carried out by parietal cortex.

MRI signal changes in the white matter after corpus callosotomy

Magnetic resonance imaging (MRI) changes reported after corpus callosotomy include hyperintensity in the corpus callosum, perifalcine hyperintensity caused by surgical retraction, and acute changes associated with surgical complications. The authors have observed MRI signal changes in the cerebral white matter of corpus callosotomy patients that are separate from the sectioned callosum and not clearly related to surgical manipulation or injury. Brain MRI scans were retrospectively reviewed in 25 of 38 patients who underwent anterior, posterior, or total callosotomy for refractory seizures between 1988 and 1995. Nine patients had signal changes in the cerebral white matter on postoperative MRI. Six of these patients had preoperative MRI studies available for comparison, and none of the white matter signal abnormalities were evident preoperatively. T 2 prolongation or hyperintensity on proton-density images was observed in areas including the centrum semiovale, forceps major, and forceps minor. Three patients had signal changes that had distinct borders extending only to the posterior limit of the callosotomy. MRI signal changes in the cerebral white matter after corpus callosotomy have not been previously reported and may represent distant effects of callosal section. Wallerian degeneration occurring in the neuronal processes cut during surgery could account for the signal changes.

Seizure control and mortality in epilepsy.

Mortality rates are increased among people with epilepsy, and may be highest in those with uncontrolled seizures. Because epilepsy surgery eliminates seizures in some people, we used an epilepsy surgery population to examine how seizure control influences mortality. We tested the hypothesis that patients with complete seizure relief after surgery would have a lower mortality rate than those who had persistent seizures. Three hundred ninety-three patients who had epilepsy surgery between January 1986 and January 1996 were followed after surgery to assess long-term survival; 347 had focal resection or transection, and 46 had anterior or complete corpus callosotomy. A multivariate survival analysis was performed, contrasting survival in those who had seizure recurrence with survival of those who remained seizure free. Standardized mortality ratios and 95% confidence intervals were calculated. Overall, seizure-free patients had a lower mortality rate than those with persistent seizures. This was true for the subset of patients with localized resection or multiple subpial transection. No patients died among 199 with no seizure recurrence, whereas of 194 patients with seizure recurrence, 11 died. Six of the deaths were sudden and unexplained. Most patients who died had a substantial reduction in postoperative seizure frequency. The standardized mortality ratio for patients with recurrent seizures was 4.69, and the risk of death in these patients was 1.37 in 100 person-years, whereas among patients who became seizure free, there was no difference in mortality rate compared with the age- and sex-matched population of the United States. Elimination of seizures after surgery reduces mortality rates in people with epilepsy to a level indistinguishable from that of the general population, whereas patients with recurrent seizures continue to suffer from high mortality rates. This suggests that uncontrolled seizures are a major risk factor for excess mortality in epilepsy. Achieving complete seizure control with epilepsy surgery in refractory patients reduces the risk of death, so the long-term risk of continuing medical treatment appears to be higher than the risk of epilepsy surgery in suitable candidates.

Magnetoencephalographic evaluation of anterior corpus callosotomy for intractable epilepsy in a patient with lennox-gastaut syndrome

We analyzed the preoperative and postoperative interictal magnetoencephalographic (MEG) patterns in a 32-year-old woman with Lennox-Gastaut syndrome who underwent an anterior corpus callosotomy (CC). A 37-channel biomagnetometer was used for the simultaneous recording of electroencephalogram (EEG) and MEG. Preoperatively, interictal EEG demonstrated a bilaterally synchronous spike and slow wave bursts with a maximum amplitude on the bifrontal region. The waveforms of the MEG were similar but did not completely correspond to those of the EEG. The estimated equivalent current dipoles (ECDs) originating from bilaterally synchronous paroxysmal discharges formed a dense cluster on the bilateral frontal lobes, especially on the deep midfrontal region. After anterior CC, MEG disclosed a marked reduction of the number of ECDs. The preoperative MEG patterns were thought to be representative of interhemispheric synchrony as a large dipole orientation, and these MEG paterns were partly disrupted by anterior CC.

Callosotomy in Children: Experience in the Veterans General Hospital‐Taipei

Purpose: Surgery is becoming more important for the treatment of chronic seizures in the pediatric age group. Common surgical procedures in children include anterior callosotomy and resection of focal lesions and surrounding tissue. Methods: The underlying diseases or pathologies for the chronic seizures of children included cryptogenic epilepsy, tumors, vascular lesions, dysplasia, and posttraumatic or ischemic events. Anterior callosotomy was performed, mainly for Lennox‐Gastaut syndrome. Patients with intractable secondarily generalized or generalized seizures were referred to the Hospital and selected for presurgical evaluation. Until 1996, 82 callosotomies had been performed. The surgical technique consisted of dissecting and splitting the anterior two thirds to four fifths of the corpus callosum through a frontal interhemispheric approach. Intraoperative precallosotomy and postcallosotomy electrocorticography (ECoG) studies were performed. Results: The mean age at the time of the operation was 8 years. The mean duration of the seizures was 5.3 years. There was no operative mortality or significant neurologic complications. With a mean follow‐up period of 1.9 years, the outcome was that 20.7% of the children were seizure free, and 41.5% showed a significant improvement. Conclusions: Sixty‐three percent of the parents were satisfied with the results. Some children showed an improvement in their hyperactivity, attention span, and social skills. However, there was no help for their mental retardation.

Treatment of Lennox-Gastaut Syndrome

Lennox-Gastaut syndrome (LGS) is a complex epilepsy of childhood characterised by an EEG demonstrating slow spike and wave complexes, multiple seizure types and cognitive impairment. Control of seizures is difficult, and the effectiveness of established anticon-vulsants is often disappointing. In the past few years, many new medications have been introduced for the treatment of partial epilepsy in adults. Emerging evidence suggests that some of these agents are also useful in LGS. Felbamate has been shown to be effective in a large controlled clinical trial, although its use is limited by life-threatening idiosyncratic reactions. Lamotrigine and topiramate have recently been shown in prospective controlled trials to be beneficial and well tolerated in patients with LGS. Vigabatrin appears to be particularly useful in children with underlying tuberous sclerosis. Novel neuroprotective strategies may be tested in the near future. The ketogenic diet has empirical efficacy in some children with intractable seizures. Vagal nerve stimulation is currently being tested in LGS, and preliminary data are encouraging. Anterior callosotomy may provide an improved quality of life in children with frequent ‘drop attacks’. These pharmacological and nonpharmacological approaches to the treatment of LGS offer new hope to patients and their families.

Interhemispheric EEG coherence after corpus callosotomy

Interhemispheric coherence analysis of scalp electroencephalograms (EEGs) in three intractable epileptic patients before and after surgical section of the anterior part of the corpus callosum was performed. Equidistant EEG periods recorded under resting conditions free of interictal epileptic activity and periods with generalized spike‐and‐wave discharges were investigated. Mean coherence values for five frequency EEG bands (delta, theta, alpha, beta 1 and beta 2) before and after corpus callosotomy were compared with each other and statistically evaluated. Anterior callosotomy led, in all cases, to a decrease of interhemispheric EEG coherence in most localizations, with the most profound decreases in the region corresponding to the section. These results support the hypothesis that the corpus callosum plays an important role in resting interhemispheric integration and EEG synchronization, similar to its central role in propagation of specific epileptic activity.

Surgical Treatment of Frontal Lobe Epilepsy

Summary: The surgical treatment of frontal lobe epilepsy (FIE) yields far less satisfactory results than that of temporal lobe epilepsy (TLE). To cope with this problem, we have introduced several new techniques, including intraoperative electrocorticography (ECoG) with sevoflurane anesthesia, corpus callostomy for diagnosis and treatment, and multiple subpial transection (MST) for eloquent cortices and extensively disseminated epileptic areas. General anesthesia was maintained by sevoflurane during surgery, and intraoperative ECoG was repeated after each procedure. When preoperative semiology suggested involvement of the bilateral frontal lobes or ECoG detected bilaterally synchronized epileptic discharges, anterior corpus callosotomy was performed before the main surgical procedure. MST was applied to unresectable motor or speech zones. This technique was also useful for treatment of widely disseminated epileptic zones. We obtained satisfactory results in surgical treatment of FLE. At >1 year of follow‐up, >70% of the patients operated on have become seizure‐free or almost seizure‐free. Relevant combined use of ECoG, callosotomy, andor MST has proved to be very effective in achieving satisfactory surgical results for treatment of FLE, especially when preoperative magnetic resonance imaging (MRI) does not detect any structural lesions.

Corpus callosotomy for medically intractable seizures.

To identify factors influencing outcome and morbidity in patients selected for corpus callosotomy, we retrospectively reviewed 23 patients with intractable generalized seizures who underwent corpus callosotomy between 1991 and 1994. Three patients had a complete corpus callosotomy, while 20 had an anterior callosotomy. Three of those patients subsequently had completion of the anterior callosotomy. Overall, 41% of patients were nearly or completely free of the seizure types targeted for surgical treatment, while another 45% had seizures less than half as frequently. Four patients developed simple partial motor seizures after callosotomy. A transient disconnection syndrome was observed in 57% of patients. The best predictor of good outcome was a normal preoperative MRI. Mentally retarded patients had poorer outcomes. Outcome was not predicted by extent of callosal section or lateralization on neurological examination, EEG, MRI, and SPECT. Completion of anterior callosotomy resulted in significant reductions in seizure frequency. Though most patients do not become seizure-free after corpus callosotomy, worthwhile palliation of an otherwise intractable illness can be achieved. An analysis of prognostic factors should lead to better selection of patients for surgery.

Parental assessment of functional outcome after corpus callosotomy.

We wished to evaluate functional outcome and parental satisfaction after corpus callosotomy. We studied a cohort of parents of 17 patients who had received an anterior corpus callosotomy > 7 months earlier (mean 26 months) for severe, intractable seizures. Parental satisfaction with the overall surgical results was the primary outcome measure. In addition, the parents assessed behavior changes that had been emphasized preoperatively as important aspects of their children's function, including alertness and responsiveness, falls and injuries, and special care needs. Degree of seizure reduction and extent of corpus callosum were also measured. The parents of 15 (88%) patients reported satisfaction with the surgical outcome. All parents who expressed satisfaction would recommend callosotomy to another family in a similar situation. The behavior change most closely associated with satisfaction was improved alertness and responsiveness (p < 0.03). Although 9 patients experienced > 80% reduction in targeted seizures, satisfaction was not reported at a greater rate as compared with the 6 patients with 50-80% reduction. Most parents report satisfaction with the outcome of their child's corpus callosotomy, but are influenced by improvement in aspects of function and behavior in addition to seizure reduction.