Spontaneous Regression of an Intraparenchymal Cyst Following Deep Brain Stimulator Electrode Implantation: Case Report and Literature Review.

BACKGROUND

The development of an intraparenchymal cyst following deep brain stimulation (DBS) surgery is an uncommon complication that lacks a clearly defined management strategy. The pathophysiology is not known and may be related to perielectrode edema or cerebrospinal fluid tracking. Previous case reports have described various therapies for symptomatic cysts, including hardware removal or conservative treatment with steroids.

CASE DESCRIPTION: We present a male patient with bilateral DBS of the ventral intermediate nucleus of the thalamus for management of essential tremor, who developed a cystic cavitation at the left electrode tip and was followed without treatment. This patient developed dysarthria, gait impairment, and unilateral motor deficits 3 months after surgery. Perielectrode edema was initially identified, eventually coalescing into a cystic cavitation at the electrode tip. Cystic regression and symptomatic improvement were observed without any surgical or medical intervention, with full cyst resolution by 17 months.

CONCLUSIONS

Only 15 additional cases have been reported in the literature, although the true incidence may be underreported because of varying practices in obtaining postoperative scans. Cysts were identified in symptomatic patients on average 6.2 months after surgery. All symptomatic cysts were treated with hardware removal or steroid therapy. Observation alone may be sufficient when a DBS-associated cyst is identified. More reports are needed to characterize this rare complication.