To determine the incidence of spreading depolarizations (SD) detected using clinical depth electrocorticography (dECOG) in severe traumatic brain injury (sTBI).

SD are a signature pathomechanism of secondary brain injury and occur commonly after sTBI. The gold standard for recording SD involves operative placement of a strip electrode. Bedside multimodality neuromonitoring (MNM) strategies include dECOG in patients who do not undergo craniectomy. The incidence of SD detected by dECOG has not been reported.

A retrospective review of patients with sTBI undergoing MNM, including dECOG, over a 6-year period. Patients with or without contralateral hemicraniectomy and/or strip ECOG were included. The incidence of SD was quantified along with relationships to 3-6 month functional outcome.

There were n=160 patients monitored with dECOG; 5 had uninterpretable recordings. Patients were 41+/-18 years of age and 124 (80%) were male. Hemicraniectomy was performed in 70 patients (45%); a strip electrode was placed in 23/74 (35%).  Patients were monitored a median of 82 hours (interquartile range 58-124 hours). SD were detected by dECOG in 21/155 (14%) and Sz in 10/155 (6.5%). Of those with strip ECOG, SD were recorded in 16/23 (70%) and Sz in 5/23 (22%). Of patients with dECOG SD, 14/21 (67%) died or remained in a state of unresponsive wakefulness vs 53/134 patients without SD (40%; p=0.04). While numbers were limited, those with strip SD similarly exhibited worse outcome (10/16 [63%] of those with strip SD vs 2/7 [29%] without strip SD).

SD were detected using dECOG in 14% of patients undergoing multimodality neuromonitoring. Relative to strip ECOG monitoring, the lower incidence of SD using dECOG may reflect smaller spatial sampling and the lack of targeted peri-injury placement. However, the prognostic significance of SD detection remains similar, with worse functional outcome when SD are detected in either dECOG or strip ECOG.