PATIENTS' EXPERIENCES WITH SPINAL CORD STIMULATION FOR LUMBAR SPONDYLOTIC PAIN: COMFORT AT THE IMPLANTABLE PROGRAMMABLE GENERATOR SITE

Objective Spinal cord stimulation (SCS) is an effective treatment for chronic lumbar and radicular pain resulting from lumbar spondylosis. However, a proportion of patients experience discomfort and complications related to the subcutaneous site of the implantable programmable generator (IPG) used to generate the stimulation for the spinal cord electrodes. A questionnaire was produced to explore patients' experiences with such issues. Methods 70 patients of mean age 63 attending the Department of Neurostimulation, Royal London Hospital, for management of their SCS for spondolytic pain were surveyed using a questionnaire. 21 responses were received. The questionnaire recorded the benefit of stimulation and addressed satisfaction with the site of the IPG device by investigating issues such as ease of use and associated complications. Where applicable, this was compared to patients' experiences with previous IPG sites. Results The mean patient–reported benefit from stimulation was 52% (SD 27%). On a five point scale (1 worst, 5 best), the median overall IPG site satisfaction level was 4 (satisfactory), while the median difficulty of programmer use with respect to the IPG site was 5 (none at all) and the median difficulty in using the recharger in ten patients with rechargeable IPGs was 4 (slight). However, seven revisions of IPG site in six patients had to be performed to achieve this level of satisfaction. IPG sites overlying rectus abdominus and external oblique were preferred to those over the anterior intercostal muscles (Kruskal–Wallis group comparison, p=0.04), and patients were less likely to be very satisfied if their IPG underlay their belt line (Pearson Chi–squared, p=0.027). None of the three dissatisfied patients recalled having a pre–operative discussion with the surgeon about IPG location, compared to thirteen of the other eighteen patients (Pearson Chi–squared, p=0.017). Conclusion This study indicates that there are significant issues with IPG satisfaction site, often requiring site revision. Patients are less likely to be satisfied with sites underlying (deep to) the belt line or overlying the anterior intercostal muscles. The questionnaire responses have provided useful information on particular issues with IPG sites that should inform a vital pre–operative discussion between the surgeon and patient on the ideal IPG site for each individual.