To identify the risk factors leading to prolonged hospitalizations due to altered arousal and speech disturbances following bilateral deep brain stimulation (DBS) surgery of the ventral intermediate nucleus in the thalamus (VIM) for treatment of essential tremor (ET).

VIM-DBS is used to treat medically refractory ET. Surgical risks of the procedure are relatively low and patients are discharged on post-operative day 1. A subset of patients experience prolonged hospitalizations due to lethargy or obtundation and dysarthria or aphasia without other perioperative complications. The etiology of these events remains obscure. We undertook a retrospective case review to identify risk factors for these events.

Patients who experienced a prolonged hospitalization (n=10) were similar to patients who did not (n=91) in age and gender, but differed in the prevalence of untreated obstructive sleep apnea (OSN) and intraoperative electrode revision. Of the patients who experienced a prolonged hospitalization, 40% had untreated OSN compared to 7.6% among patients discharged on time, while another 40% were deemed high risk for OSN at the pre-operative medical clearance appointment, compared to 14.2% among patients discharged on time. The prevalence of intraoperative electrode revision was also higher in the patients with prolonged hospitalization at 70%  compared to 16% in the patients who were discharged on time.

Prolonged hospital stay due to altered arousal and speech disturbance after VIM-DBS is not uncommon. This retrospective review suggests that these events may be related to both treatable patient characteristics (ie, OSN) and to characteristics of the procedure (ie, electrode revision).