Cystic Lesions as a Rare Complication of Deep Brain Stimulation

Development of Unilateral Peri-Lead Edema Into Large Cystic Cavitation After Deep Brain Stimulation: A Case Report

Background and Importance

Deep brain stimulation (DBS) has been approved to treat a variety of movement disorders, including Parkinson's disease (PD), essential tremor, and dystonia. Following the DBS surgery, some perioperative and even delayed complications due to intracranial and hardware-related events could occur, which may be life-threatening and require immediate remedial measures.

Clinical Presentation

We report a case of an older woman with advanced PD who developed the unique complication of unilateral cyst formation at the tip of the DBS electrode after undergoing bilateral placement of subthalamic nucleus DBS. After a period of controlled motor symptoms, the patient showed new neurological deficits related to right peri-lead edema. However, the new neurological symptoms regressed quickly over several days with stereotactic implantation of a puncture needle to drain the cyst fluid without removing the affected lead.

Conclusion

The occurrence of an intraparenchymal cyst following DBS surgery is a rare but life-threatening complication that could relate to edema around the electrodes or cerebrospinal fluid tracking. Stereotactic aspiration makes the intracranial cyst regress safely and effectively and ensures that the electrode is in the optimal position of the target nucleus to achieve an effective DBS surgery.

Intraparenchymal Symptomatic Cyst Formation Around the Deep Cerebellar Stimulation Electrode

Intraparenchymal cyst formation around a deep brain stimulation electrode is a rare complication. This is the first report of intraparenchymal cyst formation along a deep cerebellar stimulation electrode in the posterior cranial fossa. The patient was a 27-year-old man with DYT-1 early-onset isolated dystonia who received bilateral deep cerebellar stimulation. He developed dizziness, nausea, and dysarthria 1 month following the deep cerebellar stimulation surgery. Head computed tomography revealed multiple cysts along the left electrode. The contrast medium of computed tomography did not enhance the appearance of the cystic lesions. We confirmed the absence of fever and sterile cerebrospinal fluid. Steroid therapy for 3 weeks was not radiologically and symptomatically useful. He underwent aspiration surgery. The cyst fluid was light yellow, sterile, and rich in protein. Despite substantial improvement in nausea and dysarthria within 1 week postoperatively, dizziness required 1 month to recover. Cystic formations gradually decreased with time.

Surgical Treatment of Parkinson's Disease: Devices and Lesion Approaches

Surgical treatments have transformed the management of Parkinson's disease (PD). Therapeutic options available for the management of PD motor complications include deep brain stimulation (DBS), ablative or lesioning procedures (pallidotomy, thalamotomy, subthalamotomy), and dopaminergic medication infusion devices. The decision to pursue these advanced treatment options is typically done by a multidisciplinary team by considering factors such as the patient's clinical characteristics, efficacy, ease of use, and risks of therapy with a goal to improve PD symptoms and quality of life. DBS has become the most widely used surgical therapy, although there is a re-emergence of interest in ablative procedures with the introduction of MR-guided focused ultrasound. In this article, we review DBS and lesioning procedures for PD, including indications, selection process, and management strategies.

Does post-operative symptomatic lead edema associated with subthalamic DBS implantation impact long-term clinical outcomes?

INTRODUCTION

Post-operative, non-hemorrhagic, non-infectious symptomatic delayed edema around the DBS lead is an uncommon complication of DBS surgery. We investigated whether this complication impacts clinical outcomes or has long-term sequelae.

METHODS

All Parkinson's disease (PD) patients with subthalamic nucleus (STN) DBS implantation who developed delayed symptomatic lead edema were identified. UPDRS part III motor, Parkinson's Disease Questionnaire (PDQ-39) total and MoCA scores were analyzed to assess motor outcome, quality of life and cognitive status at 1 year.

RESULTS

A total of 260 patients underwent 482 STN lead placements. Of these, 16 patients (20 leads, 4.1% of total 482 leads) developed this delayed complication. None of the patients had edema on immediate post-operative scan. Patients presented with varied symptoms including speech difficulty (n = 8), mild confusion (n = 6), headaches (n = 4), gait difficulty (n = 4) and seizures (n = 3). The mean duration for the diagnosis was 5.8 days after lead implantation and the mean duration for which follow-up CT scans reported complete/near complete resolution or improvement of edema was 4.7 weeks (range 2-10 weeks). At 1-year post-DBS, UPDRS motor scores improved significantly (42.5%, p < .001); quality of life improved, but the change was not statistically significant (21.3%, p = .197). There was no decline in cognitive function at 1 year (26.6 vs 26.4, p = .567). No long-term complication related to lead edema occurred in these patients.

CONCLUSION

Symptomatic lead edema after DBS surgery is an uncommon complication which typically resolves over time. In our series, there were no long-term sequelae of this complication and clinical outcomes were comparable to that reported in the literature.

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.