Posterior two-thirds corpus callosotomy in the semisitting position: Technical advantages and outcomes in...

Posterior corpus callosotomy is an established palliative surgical option for patients with drug-resistant generalized epilepsy, especially with drop attacks. Although the posterior approach has been described, the semisitting position remains underutilized and rarely documented in literature. This technique enhances midline visualization, reduces retraction, and allows safer access to posterior interhemispheric structures. Our series illustrates the technical feasibility of this approach, accompanied by operative descriptions and video documentation.

We retrospectively reviewed 10 patients who underwent posterior two-thirds corpus callosotomy via a right occipital craniotomy in the semisitting position. The surgical corridor enabled direct access to the splenium, Galenic venous system, and pericallosal arteries with only transient use of a fixed retractor. The retractor can be subsequently removed after splenial exposure with sufficient brain relaxation. The clinical and operative outcomes seizure frequency, antiseizure medication changes, hospital disposition, and complications were collected.

Ten patients (mean age = 27 years, epilepsy duration = 22.6 years) underwent the procedure without complications. The median follow-up was 18 (interquartile range [IQR] = 12-28) months. Seven patients experienced drop attacks, and median monthly drop attacks decreased from 36 (IQR = 2.5-70) to 0 (IQR = 0-23) postoperatively. Of those who experienced drop attacks, five of seven achieved complete resolution, and the remaining two achieved a reduction of 66% and 68%. Additionally, nine of 10 patients experienced other seizures besides drop attacks, and these seizures were reduced from 84 (IQR = 72-112) to five (IQR = 1-16) per month. Two patients developed transient disconnection syndrome that resolved spontaneously. No cases of hemodynamic instability or venous air embolism occurred.

The semisitting posterior callosotomy technique appears to offer favorable anatomical access and gentle tissue handling, with no intraoperative complications in this limited series. Although these preliminary findings are encouraging, further studies should determine its broader applicability and long-term outcomes. This approach may warrant consideration as a surgical option in selected patients with drop attack-dominant epilepsies.