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Background Stereoelectroencephalography (SEEG) is used to identify the epileptogenic zone (EZ) in patients with epilepsy for potential surgical intervention. Occasionally, the EZ is difficult to localize even after an SEEG implantation. Objective To demonstrate a safe technique for placing additional electrodes in ongoing SEEG evaluations. Describe efficacy, complications, and surgical outcomes. Methods An operative technique which involves maintaining previously placed electrodes and sterilely placing new electrodes was developed and implemented. All patients who underwent placement of additional SEEG electrodes during the same admission were retrospectively reviewed. Results A total of 14 patients met criteria and had undergone SEEG evaluation with 198 electrodes implanted. A total 93% of patients (13/14) had nonlesional epilepsy. After unsuccessful localization of the EZ after a mean of 9.6 d of monitoring, each patient underwent additional placement of electrodes (5.5 average electrodes per patient) to augment the original implantation. At no point did any patients develop new hemorrhage, infection, wound breakdown, or require any kind of additional antimicrobial treatment. A total 64% (9/14) of patients were able to undergo surgery aimed at removing the EZ guided by the additional SEEG electrodes. A total 44% (4/9) of surgical patients had Engel class I outcomes at an average follow-up time of 11 mo. Conclusion Placing additional SEEG electrodes, while maintaining the previously placed electrodes, appears to be safe, effective, and had no infectious complications. When confronted with difficult-to-localize epilepsy even after invasive monitoring, it appears to be safe and potentially clinically effective to place additional electrodes during the same admission.

Anterior column realignment (ACR) with anterior longitudinal ligament (ALL) release from a lateral transpsoas approach is increasingly being used as a minimally invasive technique to restore lordosis. Safe execution requires a plane between the ALL and the anterior vasculature. An unfavorable plane on preoperative imaging is a contraindication to using the technique. We describe a patient undergoing multistage minimally invasive correction of a flat-back deformity who had an unfavorable plane between the ALL and vasculature at L4-5. Patient consent was provided, and Institutional Review Board approval was not required. To safely complete the ALL release and ACR, we elected to sharply incise the lateral aspect of the ligament at L4-5 with direct control of the vessels during the anterior approach for an L5-S1 anterior lumbar interbody fusion. We then moved to the lateral transpsoas approach and used controlled distraction techniques to complete the ALL release and then to complete the ACR in a standard fashion. We ultimately achieved excellent realignment with correction of the patient's flat-back deformity using minimally invasive surgical techniques while minimizing vascular risk. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.