gms | German Medical Science

Objective: Chronic neuropathic pain of the peripheral nerves of the upper extremities is a common problem following trauma, injury or surgery, but may also occur spontaneously. Treatment of choice is conservative, pharmacological and multimodal. In cases of refractory pain invasive treatment options of neuromodulation may be considered. Stimulation of the dorsal root ganglion (DRG) is a novel therapeutic option using specific designed and developed stimulation leads. The initial clinical experience of a single centre with 5 patients is presented.

Method: Refractory chronic neuropathic pain of the upper extremity was diagnosed in 5 patients (3 female, 2 male; age: 29-51 years). Chronic pain developed after unilateral ulnar nerve (n=2), median nerve (n=2) or radial nerve surgery (n=1). A computed tomography guided sequential infiltration of the DRG's of C6 to Th2 was performed preoperatively with local anaesthesia to identify the targets for lead implantation. The quadripolar leads (total n=12 leads) were implanted at the spinal ganglion of C6 (n=4), C7 (n=4), C8 (n=2), Th1 (n=1) and Th2 (n=1). A test trial with an external stimulation device was conducted. In case of pain reduction of > 30 and concomitant withdrawal of analgesics the indication for implantation of the permanent stimulation device was given.

Results: In all patients the leads were positioned at the targeted DRG and consecutive intraoperative test stimulation was performed. In 4/5 cases two leads were implanted at the DRG of C6 and C7 and complete coverage of the pain area with pleasant paraesthesias was achieved. In one patient with neuropathic pain after ulnar nerve injury the leads were implanted at the DRG´s of C8, Th1 and Th2. Significant pain reduction was achieved in all patients. In contrast to spinal cord stimulation (SCS) the stimulation intensity is lower and position-dependant unpleasant stimulation effects are remarkable reduced. In the follow-up course in one case each lead dislocation and breakage of the extension was seen.

Conclusions: Neurostimulation of the DRG is a safe and effective novel procedure to treat neuropathic pain syndromes after nerve lesion of the upper extremity. In comparison to SCS certain advantages like lower amplitudes, less motion dependant effects and a more consistent stimulation were observed. This specific procedure should be performed in experienced centres for functional neurostimulation and invasive neurosurgical pain therapies.