Selective peripheral denervation for refractory cervical dystonia: a single-center retrospective analysis of 160 cases.

[OBJECTIVE] Cervical dystonia (CD) is the most common focal dystonia, characterized by abnormal head postures and pain, often refractory to botulinum toxin therapy. Selective peripheral denervation (SPD) remains a key surgical option, but long-term outcomes in large cohorts are underreported. The purpose of this study was to evaluate the long-term outcomes of SPD in patients with botulinum toxin-refractory CD, focusing on symptom severity, pain, and head posture improvement.

[METHODS] This retrospective study included 160 adults (mean ± SD age 54 ± 12.0 years, 46% male) with refractory CD who underwent SPD at a single center by a single surgeon from January 2005 to July 2023. Outcomes were assessed using subjective clinical measures and the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), which was calculated retrospectively from clinical records. The modified Bertrand technique involved selective denervation and myotomies tailored to each patient's dystonic pattern. TWSTRS scores were analyzed at baseline, 3 months, 1 year, and final follow-up (mean ± SD 10.3 ± 9.0 months). Time to minimal clinically important difference (MCID) (≥ 12-point TWSTRS drop) was evaluated with covariate-adjusted Kaplan-Meier modeling (ever vs never revised, evaluated with the log-rank test) and a counting-process Cox model with revision as a time-dependent covariate.

[RESULTS] Among 160 patients (mean follow-up duration 21.6 ± 35.6 months), TWSTRS improved by 73.5% at 3 months and 61.3% at last follow-up (p < 0.001). Median time to MCID was 3.0 months for never revised patients versus 22.0 months for ever revised patients (log-rank chi-square statistic = 19.09, p < 0.0001). In a time-dependent Cox model, revision surgery was significantly associated with higher likelihood of achieving MCID (HR 2.31, p < 0.005). Pain relief and improved head posture were reported in over 50% of patients. Complications were minimal, and recurrence was observed in 4.2% of cases. Outcomes were consistent with or exceeded those reported in the literature with either SPD or deep brain stimulation (DBS).

[CONCLUSIONS] SPD is an effective and durable surgical option for refractory CD, significantly improving pain, posture, and quality of life. Although revision surgery delayed time to improvement, it significantly increased the likelihood of achieving meaningful clinical improvement. Overall efficacy aligns with the existing literature, reinforcing its role as a first-line surgical intervention. Further studies should explore strategies to enhance long-term outcomes and delineate the role of SPD relative to DBS.