Spinal cord stimulation electrode design: A prospective randomized, controlled trial comparing percutaneous and laminectomy electrodes

Permanent Paddle-lead Trial for Spinal Cord Stimulation

Objectives

A significant number of chronic pain patients rely on spinal cord stimulation (SCS) for treatment of their intractable pain. A screening trial using percutaneous electrodes is an integral step for predicting a successful treatment course with a permanent SCS system. Most of these trials are performed in an outpatient ambulatory surgical center and some in the office setting. However, there are select patients who are considered poor candidates for percutaneous trials. We present the initial report of patients who have received surgical implantation of permanent paddle-leads for SCS trials at our institution and show that this was a safe and effective alternative for our patients who could not undergo percutaneous trials. 

Methods

We retrospectively reviewed the hospital charts of 12 patients who underwent permanent surgically-implanted paddle-lead trials from 2014 to 2017. Success was considered positive with a 50% reduction in pain rating. If positive, patients were brought back to the operating room to have the implanted leads connected to an internalized pulse generator.   

Results

All 12 patients met the criteria for a successful trial. Only one patient had his SCS system surgically removed after nine months. None of our patients reported or returned with paddle-lead migrations or infections. 

Conclusions

We report that surgically-implanted paddle-lead trials were a safe and effective alternative to percutaneous trials in our patients who were deemed poor candidates for percutaneous trials. No complications occurred and all of our patients received a second surgery for internalization of the SCS system. Patients who have previously failed percutaneous trials may be false-negatives to SCS. 

Efficacy of spinal cord stimulation for neuropathic pain: assessment by abstinence

Assessment of the efficacy of spinal cord stimulation (SCS) against neuropathic pain remains problematic. Some patients may underestimate this, as revealed by their reaction to stimulator malfunction. This study investigated whether abstinence from SCS would provide an indication of its effectiveness. Patients were invited to complete two brief questionnaires each day for 50 days including two periods of 14 days without stimulation. Pain level, sleep quality, activity level and drug intake were recorded. Of 75 patients thought to be using their stimulators, 12 did not respond to the invitation, eight had unresolved technical problems and one no longer needed SCS. Of the 54 remaining, 10 did not wish to be without SCS and 15 declined without giving a reason. Thus 29 agreed to take part but three then dropped out through illness and questionnaires were not received from 10. Ten returned completed questionnaires but failed to follow the protocol; five of these were unable to leave their stimulators off. Only six took part correctly. Twenty of the 29 had received a preliminary explanatory home visit and for nine this was done by telephone. The former produced a considerably higher yield. All six who completed the study correctly had statistically significantly lower pain scores during stimulation. Four had improved sleep but only one reduced his medication and none of the six increased their activity levels. Correlation with previous clinical assessments is discussed. It is concluded that the abstinence principle might provide a useful tool but its power is very methodology-dependent.

Failure modes of spinal cord stimulation hardware

Object

Epidural spinal cord stimulation (SCS) is effective at treating refractory pain. The failure modes of the implanted hardware, however, have not been well studied. A better understanding of this could aid in improving the current procedure or designing future devices.

Methods

The authors reviewed electronic charts and operative reports of 289 patients who had undergone SCS implantation between 1998 and 2002 at the Cleveland Clinic Foundation. Data were collected on demographics, type of hardware, date of implantation procedure, indication for treatment, time to failure, and failure mode. Data were then analyzed to identify significant differences.

A total of 577 procedures were performed, 43.5% of which involved revision or removal of SCS hardware. The most common indication was complex regional pain syndrome 1, and this was followed by failed–back surgery syndrome. The median number of procedures per patient was two. Approximately 80% of all leads were the percutaneous type. The majority (62%) of leads were placed in the thoracic region, and 33.5% of all leads required revision. Poor pain relief coverage was the most common indication for revision. Surgically implanted leads broke twice as often as percutaneous leads. In 46% of the patients, hardware revision was required, and multiple revisions were necessary in 22.5%. Three-way ANOVA revealed significant differences in failure mode rates according to location (cervical compared with thoracic, p = 0.037) and failure modes (p = 0.019). Laminotomy leads tended to break and migrate sooner than percutaneous leads. Thoracic leads became infected sooner than cervical leads.

Conclusions

The results of this analysis of SCS hardware failures may be used as a basis for refining surgical technique and designing the next generation of SCS hardware.

Electroanalgesia: its role in acute and chronic pain management

Interest in nonpharmacologic alternatives to conventional analgesic drugs for the management of acute and chronic pain has lead to an evaluation of the use of electroanalgesic therapies.