Circular stereotactic callosotomy: a preliminary report. Technical note

The Evolution of Corpus Callosotomy for Epilepsy Management

Corpus callosotomy, first used in the management of epilepsy by William P. van Wagenen in 1940, was for years a contentious procedure. Two decades later, Nobel Laureate Roger W. Sperry's split-brain studies inspired surgeons to reexamine the role of corpus callosotomy in the control of epileptic seizures. In 1962, Joseph Bogen and Philip Vogel performed complete corpus callosotomies in patients with a history of generalized seizures. The identification of a set of postsurgical disconnection symptoms and other neurologic deficits begged the improvement of the surgical technique. Modifications to the operation, including anterior callosotomy, posterior callosotomy, partial callosotomy, staged callosotomy, microsurgical techniques, and radiosurgical techniques, continue to refine the procedure.

Morphometric Analysis of the Corpus Callosum Using Cadaveric Brain: An Anatomical Study

Purpose:

The present study was conducted to measure the longitudinal and vertical lengths of the brain hemisphere, longitudinal length of the corpus callosum (CC), and distances of CC from the frontal and occipital poles, in order to define its topographic location within the brain hemispheres.

Materials and Methods:

Fifty formalin-fixed human brains were dissected in the midsagittal plane. The parameters measured were as follows: (i) straight distance between frontal and occipital pole (AB); (ii) vertical distance (height) between the upper and lower surface of the brain hemisphere (CD); (iii) frontal pole to anterior-most point of CC (EG); (iv) occipital pole to posterior-most point of CC (ZO); (v) anterior-most point to posterior-most point of CC (EZ); and (v) anterior edge of genu to the upper end of lamina terminalis (EF).

Results:

The mean value of AB, CD, EG, ZO, EZ, and EF was 15.47 ± 0.94 cm, 9.48 ± 0.83 cm, 3.31 ± 0.29 cm, 5.65 ± 0.54 cm, 6.96 ± 0.55 cm, and 2.1 ± 0.39 cm, respectively. AB had the strongest positive correlation with ZO (0.79), whereas CD (height) had it with EZ (0.59). Both AB and CD had a strong positive correlation with EZ. The ratios EZ/AB = 0.45 (P = 0.001) and EZ/CD = 0.73 (P = 0.003) illustrated a steady and significant proportions, present in all the brains studied. Although the mean values of all the parameters were greater in males than in females, only two parameters (ZO and EZ) showed statistically significant (P < 0.05) gender differences.

Conclusion:

The precise anatomical knowledge regarding the morphometry of CC will provide baseline data for the diagnosis and progression of disease affecting it.

Efficacy and safety of corpus callosotomy after vagal nerve stimulation in patients with drug-resistant epilepsy

OBJECTIVE Vagal nerve stimulation (VNS) and corpus callosotomy (CC) have both been shown to be of benefit in the treatment of medically refractory epilepsy. Recent case series have reviewed the efficacy of VNS in patients who have undergone CC, with encouraging results. There are few data, however, on the use of CC following VNS therapy. METHODS The records of all patients at the authors' center who underwent CC following VNS between 1998 and 2015 were reviewed. Patient baseline characteristics, operative details, and postoperative outcomes were analyzed. RESULTS Ten patients met inclusion criteria. The median follow-up was 72 months, with a minimum follow-up of 12 months (range 12-109 months). The mean time between VNS and CC was 53.7 months. The most common reason for CC was progression of seizures after VNS. Seven patients had anterior CC, and 3 patients returned to the operating room for a completion of the procedure. All patients had a decrease in the rate of falls and drop seizures; 7 patients experienced elimination of drop seizures. Nine patients had an Engel Class III outcome, and 1 patient had a Class IV outcome. There were 3 immediate postoperative complications and 1 delayed complication. One patient developed pneumonia, 1 developed transient mutism, and 1 had persistent weakness in the nondominant foot. One patient presented with a wound infection. CONCLUSIONS The authors demonstrate that CC can help reduce seizures in patients with medically refractory epilepsy following VNS, particularly with respect to drop attacks.

Corpus callosotomy in children

INTRODUCTION

For children of medical resistant epilepsy without resectable epileptogenic zone, corpus callosotomy and vagus nerve stimulation (VNS) therapy are the two commonly used palliative epilepsy surgeries that can be considered. Although their routes and mechanisms to control epilepsy are different, both surgeries have shown their efficacy in selected candidates. The most common candidates for palliative surgery are in infants and children with organic encephalopathic types of epilepsy including infantile spasms/West syndrome, Lennox-Gastaut syndrome (LGS), severe epilepsy with multiple independent spike foci (SE-MISF) and selected symptomatic partial epilepsy to relief seizures and to stabilize co morbidities (Hirsch and Arzimanoglou, Revue Neurologique [Hirsch E and Arzimanoglou A, Rev Neurol (Paris). 160 Spec No 1:5S210-S219, (2004); Ohtahara S and Yamatogi Y, J Clin Neurophysiol 20(6):398-407, (2003); Wheless JW and Epilepsia 45(Suppl 5):17-22, (2004); Trevathan E, J Child Neurol 17 Suppl 2:2S9-2S22, (2002)].

DISCUSSION

Callosotomy is a major and destructive but affordable surgical procedure as compare to the relative simple but costly extracranial procedure of VNS therapy. However, callosotomy is a safe and effective palliative operation in neurosurgeons familiar with the surgical procedure. Equipments for callosotomy can be as simple as headlight and binocular loupes, self-retention brain retractor, bipolar cauterization, and simple microinstruments.