Abstract:

Objective

To evaluate the therapeutic efficacy and safety of combined caudal part of the zona incerta (cZI)-deep brain stimulation (DBS) with ventral intermediate nucleus (Vim)-DBS for the treatment of essential tremor(ET).

Methods

A retrospective analysis of 11 patients with ET treated with dual-target DBS at Neurosurgery Department of Shengli Oilfield Central Hospital from January 2020 to June 2023 were conducted.Postoperatively, all patients underwent immediate cranial CT to confirm electrode placement and to rule out complications such as cerebral hemorrhage and infarction.The Fahn-Tolosa-Marin tremor rating scale(FTMTRS)was used to assess motor symptoms preoperatively,on the day of device activation, and at 1, 3, 6, and 12 months post-activation to calculate the rate of symptom improvement and to evaluate the effectiveness of the treatment.Additionally, adverse reactions related to stimulation to assess the safety of the treatment were recorded.

Results

All 11 patients (2 with unilateral and 9 with bilateral treatment) successfully completed the dual-target DBS procedure.Cranial CT scans showed that the electrode positions matched the preoperative planned targets, and all patients experienced a significant microlesion effect postoperatively.The median follow-up time was 26 months(ranging from 12 to 42 months), with no observed complications such as infarction, hemorrhage, infection,allergy, or rejection.At one month postoperatively, during the initial device activation, patients selected monopolar stimulation at contacts in the cZI nucleus, with 2 patients adjusting contacts to the Vim target during follow-up.Tremor symptoms in all patients showed significant improvement postoperatively, with improvement rates on the day of activation and at 1, 3, 6, and 12 months post-activation being 70.21%,61.34%, 67.28%, 72.04%, and 75.04%, respectively.Post - activation, adverse reactions included dysarthria in 1 case, ataxia in 2 cases, transient limb numbness in 3 cases, and lower limb weakness in 4 cases,all of which were resolved or tolerated after adjusting the contact points or parameters.

Conclusion

cZI-DBS can effectively improve the clinical symptoms of patients with ET.The combined use with Vim-DBS enhances the flexibility of programming and reduces the risk of a second surgery for electrode reimplantation.Moreover, the procedure has fewer surgical complications, demonstrating good safety and feasibility.

Key words: Essential tremor, Deep brain stimulation, Caudal part of the zona incerta, Posterior subthalamic area, Ventral intermediate nucleus, Dual-target