Collapse Following Subgaleal Negative Pressure Drain Application: Reverse Brain Herniation or Trigeminocardiac Reflex?

A negative-suction pressure subgaleal drain is most com-monly applied during the closure of the cranial defect to reduce the risk of postoperative hematoma formation. The literature revealed few cases of life-threatening subgaleal negative pressure drain (SNPD) associated complications. 1 We report a probable case of reverse brain herniation (RBH) or trigeminocardiac re fl ex (TCR) from application of SNDP following craniotomy. Both RBH and TCR are the least understood complications of SNDP. TCR is an autonomic brainstem re fl ex that manifests as sudden bradycardia, hypotension, and gastric hypermotility. This re fl ex occurs when there is a stimulation of the trigeminal nerve or any of its branches. Though, believed to be an inherent protective re fl ex, it can lead to adverse outcome if exaggerated. 2 Whereas RBH has been reported following cerebrospinal fl uid (CSF) diversion procedure or removal of CSF during posterior fossa surgery, 3 but has also been seen following SNDP in supratentorial surgery. 1 RBH is the least understood of brain herniation syndromes and is a rare complication of ventriculoperitoneal shunt 4 and also after SNDP placement. 5 The early identi fi cation of RBH and TCR during scalp closure is imperative to prevent a precipitous drop in heart rate, blood pressure, and further circulatory arrest. Knowledge of both these