gms | German Medical Science

Introduction: The number of lumbar spinal procedures is increasing significantly over the last 10 years. One can assume that the incidence of chronic pain following lumbar spinal operations, so called “failed back surgery syndrome (FBSS)” will increase and become a major problem also. Whereas the lumbar pain is mainly diagnosed as nociceptive or mixed pain, the radicular pain is often considered to be the neuropathic component. Initial treatment of FBSS is conservative including analgesics, physiotherapy and psychological treatment. Spinal cord stimulation (SCS) is an invasive neuromodulation procedure and performed for more than 30 years for various chronic pain syndromes. The clinical experiences of a single center including a prospective patient sample are presented.

Material and methods: SCS was performed in 100 patients with FBSS and chronic low-back and leg pain. In all cases a symptomatic cause like recurrent herniated disc or significant stenosis was excluded. Indication for SCS was favored in cases with predominant leg or radicular pain. The epidural implantation of quadri- or octopolar leads was performed in local anesthesia and guided by fluoroscopy. The definite position of the leads was tested by intraoperative stimulation. In all patients a test trial with an external stimulation device was performed for 3-14 days. Patients documented the pain intensity (visual analogue scale (VAS) or numeric rating scale (NRS)), daily medications and activities in a diary. Since 2013 MRI-conditional leads and stimulation devices are available and implanted.

Results: In all patients a sufficient lead placement between thoracic vertebra 8 and lumbar vertebra 1 was achieved. Intraoperative testing was conducted until more than 80% of the pain area was covered by stimulation evoked paraesthesias. During the test trial a significant pain reduction of more than 30% was documented in 88/100 patients. In these cases a reduction or withdrawal of analgesic medication was initiated and the permanent neurostimulator was implanted in general anaesthesia. In the remaining 12 patients the leads were explanted and in 10 of these patients the indication for intrathecal drug delivery was discussed. Main complications were lead dislocations, wound infections and technical failures including lead or extension fracture and deep battery discharge in cases of rechargeable stimulation devices. Noteworthy, during follow-up a high percentage of patients (>90%) reported a distinct satisfaction with the neuromodulation therapy and would undergo the procedure again. After a mean follow-up of 4 years (range: 2 months up to 9 years) a significant pain reduction and active SCS was evaluated in 50/77 patients (65%), 11 patients were lost for follow-up evaluation.

Conclusion: SCS is an effective and safe additional treatment option for patients with FBSS and predominating radicular neuropathic leg pain. SCS should be considered in selected cases of chronic pain and questionable indications like re-operations with adhaesiolysis, scar tissue revision and extension of spondylodesis. The risks and complications of the procedure are low and patient’s acceptance is high with significant improvement of quality of life. In cases of new implantations a MRI-conditional device should be preferred. An interdisciplinary german S3-guideline is published in 2013: http://www.awmf.org/leitlinien/detail/ll/041-002.html.