Dyskinetic Storm Induced by Intra-Operative Deep Brain Stimulator Placement

Abstract

Transient dyskinesia induced by deep brain stimulation (DBS) for Parkinson's disease (PD) has previously been reported as an intra-operative side effect usually indicating excellent lead placement and a positive outcome. Gener- ally, stimulation-induced dyskinesia occurs contralateral to the side of stimulation. We report a case in which a patient de- veloped a severe bilateral storm upon placement of the cannula and prior to macrostimulation during DBS surgery of the left subthalamic nucleus. This case illustrates that rarely dyskinetic storms may occur intra-operatively and become generalized. was off medication for 20 hours at the start of the case, and 22.5 hours following lead placement at the end of the case. After recording and identification of the STN target, a modi- fied UPDRS was performed and then a DBS electrode was inserted through a guide cannula (which was advanced to the target and then retracted) into the physiologically refined target. Prior to lead placement, no dyskinesia was observed. A slight dyskinesia was seen almost immediately in the right upper extremity. While performing a modified UPDRS, the dyskinesia worsened in the right upper extremity, spread to the right lower extremity, and then was observed in all ex- tremities (see video). The patient's mental status was tested, and he was completely alert and oriented and indicated that this was a typical bout of severe dyskinesia. He then quickly progressed into a storm, requiring multiple staff to hold him in position and to protect the integrity of the head ring. Propofol at a dose of 180 mg (in four boluses of 40mg, 60mg, 40mg, and 40mg) was required to sedate him and control the dyskinesia. Each DBS contact 0-3 was tested at 135 Hz and a pulse width of 90 ms; however, it was diffi- cult to discern any worsening of symptoms or to segregate side effects because of the severity of the dyskinesia. Dyski- nesia was not worsened by DBS; however, because of its severity, the examination was difficult. In recovery, no fur- ther dyskinesia was noted. He stayed in the hospital over- night. The patient's levodopa was held overnight and he re- turned to his normal dose of medication the next morning and was discharged without incident. During the first 30 days post-operatively, the patient reported dyskinesia at a similar level to his dyskinesia prior to surgery. The patient had a second DBS surgery to implant the opposite STN six months after his first implantation without incident. Follow- ing the first DBS surgery, he had stimulation induced dyski- nesias during programming and then chronically, but they mostly abated with slight medication and programming ad- justments (he complained of mild dyskinesias mainly late in the day). Following his second DBS (right STN) he reduced his carbidopa/levodopa further to 1 tablet at each dose and spread the interval to every four hours. Six months following his second DBS he reported only very rare non-daily dyski-