Gamma Knife Radiosurgery, central lateral thalamotomy and chronic neuropathic pain. A prospective single center study with long term follow-up

Abstract

ObjectiveNeuropathic pain affects approximately 7-10% of the general population. Its risk tends to rise with age and can impact individuals of any gender. Managing neuropathic pain often requires a combination of strategies. Surgical treatment is considered for patients who fail medical therapy and develop chronic symptoms. The posterior part of the central lateral nucleus (CLp) represents a promising target for the treatment of these cases.We present our experience in using Gamma Knife Surgery (GKS) on the posterior part of the central lateral nucleus (CLp) for refractory neuropathic pain, examining its long-term efficacy and safety in patients with one of the longest pre-treatment pain duration in the literature. Furthermore, we examined certain factors that might influence the outcome of this technique. MethodsWe conducted a prospective study involving 9 patients who underwent GKS between 2020 and 2023.We employed Icon model Gamma Knife and Vantage model stereotactic frame. The planning process encompassed a dual localization system. The assessments involved the use of both the Visual Analogue Scale (VAS) and Barrow Neurological Institute (BNI) scales (6,12-month and then, annually). Data analysis was carried out using SPSS25. ResultsOur series consisted of 6 women and 3 men with an average age of 52.3±17.4 years.A maximum dose of 130 Gy was administered (eight bilateral, one unilateral).The mid-term postoperative period (1 year) showed that eight patients (88.9%)experienced significant pain relief (VAS p=0.011;BNI I-IIIa).The median follow-up time was 24.8±8.2 (12-37 months). At the last assessment, all patients maintained their improvement (VAS p=0.018;BNI I-II-IIIa/b).We found no association between patient age (p=0.329),duration of pre-treatment pain (p=0.469),multiple previous surgical treatments (p=0.750),or the pain's etiology (p=0.25),and poorer outcomes post CLp thalamotomy.None of the cases has experienced a recurrence so far.Both permanent morbidity and mortality were 0%. ConclusionsOur findings suggest that bilateral ablation of the CLp using GKS is both effective and safe for treating drug-resistant neuropathic pain.This simple,accurate and non-invasive surgical technique effectively achieves pain control across various localized areas and sustains a lasting clinical response,even in patients with multiple previous surgical interventions or prolonged pain duration. These findings encourage us to consider this technique as a highly beneficial strategy for these patients.