Epileptic Disorders - Editor's Choice
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Peng-Fan Yang, Zhen Mei, Qiao Lin, Jia-Sheng Pei, Hui-Jian Zhang, Zhong-Hui Zhong, Jun Tian, Yan-Zeng Jia, Zi-Qian Chen, Zhi-Yong Zheng
Commentary by Pr. Douglas Nordli Jr, Associate Editor
From my perspective as a pediatric epileptologist involved in single-stage ECoG-guided resections for the past 25 years one of the most challenging aspects of pediatric temporal lobe surgery for intractable epilepsy due to cortical dysplasia is making sure all of the posterior extent of the lesion has been identified so that the surgeon can achieve a complete resection.
This is complicated because the lesion may sometime extend posteriorly and inferiorly a considerable distance beyond the usual margins of a typical temporal lobe resection necessitating a multilobar resection with encroachment into the parietal and occipital lobes. In the past, with the limited surgical exposures for a standard temporal lobectomy and no navigational guidance systems this was very challenging. Nowadays, in centers all around the world we have learned to expect this extent of the lesion and to anticipate the need for more extensive surgery in these cases.
A residual challenge is the best approach for children who have total or near-total involvement of the temporal parietal and occipital lobes with lesions which by themselves, do not need to be resected. Here, multilobar resections will result in a removal of a large amount of substrate and leave large defects, each with their attendant complications. A functional disconnection of these areas may be an elegant alternative approach, particularly if the patient already has a contralateral visual field defect.
P-F Yang and colleagues describe their experience with 12 children who underwent disconnection of the posterior quadrant for intractable epilepsy and highlight the feasibility of this approach. For the most part, these children had concordant clinical neurophysiological, MR and PET pre-operative results implicating the posterior quadrant. None had markedly discordant findings and none had lesions that would require resection for proper management, such as tumors or vascular malformations. Their surgical approach allowed for small incisions with minimal blood loss. Once they mastered the technique of sparing bridging vessels there were no significant unanticipated complications. All children had expected contralateral field defects, as expected. The outcomes at an average of 34 months were favorable with 75% of patients being seizure-free. Comparison of pre- and post-operative neuropsychological testing showed significant improvement (Global IQ mean of 58 versus 47, p < 0.04).;This very useful contribution to the surgical literature supports the use of a disconnection strategy for patients with extensive involvement of the posterior quadrant with lesions that by themselves do not require resection.