The Effects of Invasive Motor Cortex Stimulation for Neuropathic Pain: Do We See the Full Picture?

Invasive motor cortex stimulation (iMCS) can be a last-resort treatment of chronic neuropathic pain syndromes. There is evidence that iMCS was found to influence pain intensity, quality of life scores, and pain medication intake in clinical practice. Albeit, qualitative studies published over the last years showed that the expectations and experiences of patients have a significant impact on treatment outcomes. This paper focus on these experiences of chronic neuropathic pain patients treated with iMCS.

The aim of this interview study was to map the experiences of patients treated with iMCS in order to evaluate the multidimensional effects of iMCS.

Twenty-eight patients with chronic neuropathic pain treated with iMCS between 2005 and 2018 were interviewed individually. All interviews were semi-structured using a predefined topic list. An inductive iterative process was performed during the interviews using the constant comparative method. All interviews were audio-recorded and transcribed verbatim afterwards. Transcripts were coded using direct content analysis. The derived codes were structured into categories and themes. Basic quantitative demographic data were collected, and the decrease in pain intensity after 2 years iMCS was calculated.

Content analysis of the interviews revealed ten relevant categories, which could be structured into three themes: 1. Influence of the iMCS procedure on patients' live; 2. Effects of iMCS on quality of life and participation and 3. Acceptance and satisfaction. In total, 32% (8/25) were identified as responders, and 68% (17/25) as non-responders. Most patients (71%, 20/28) indicated they would undergo iMCS again. Three patients deceased before the end of the study.

This study suggests that the effects of iMCS should be assessed in a more multidimensional way compared to only the effect on pain as patients confided that the true treatment effect and patient satisfaction were based more on improvements of their quality of life, enabling patients to participate again in society in a meaningful way. In clinical practice, this study emphasizes the need for thorough patient education and realistic expectation management prior to implantation, highlighting both potential benefits and limitations to support informed decision-making.