Peripheral Nerve Stimulation of the Thoracic Paravertebral Plexus for Chronic Neuropathic Pain

Abstract

Persistent post surgical pain is reported in 70% of patients following thoracotomy and mastectomy. This pain is often neuropathic in nature and occasionally it is refractory to traditional medical and interventional management. Neurostimulation of peripheral nerves can be a highly effective clinical modality for the management of neuropathic pain. The placement of a percutaneously sited electrode in the thoracic paravertebral plexus offers a new and novel mode of managing refractory thoracic neuropathic pain. We present 2 cases that demonstrate the effectiveness of this intervention in the long-term management of this clinical dilemma. The first case presented is that of a 61-year-old female, with unilateral neuropathic pain for 6 years following mastectomy refractory to traditional interventions. Targeted field stimulation of the thoracic paravertebral plexus resulted in significant improvement for 12 years. The second case is that of a 65-year-old male, with Type II diabetes with neuropathic thoracic pain for 6 years following multiple rib fractures (T4-T7) who responded positively to neurostimulation of the thoracic paravertebral plexus. Both of these cases demonstrate a relative reduction in pain intensity (> 80%), the elimination of oral analgesics, and improved functionality directly related to the novel use of this intervention. Effective and reproducible pain relief is achieved by specifically using a low frequency (10 Hz) and low amplitude (2 mA) stimulation technique. Equally important is that these cases highlight the increased risk of inadvertent pleural puncture with the development of a pneumothorax that can be associated with this intervention. Possible clinical, investigative and equipment modifications that need to be considered are discussed. The limitations include only 2 case reports, considered as the lowest level of evidence available in the era of evidence-based medicine, and lack of utilization of multiple other modalities of treatments utilized in managing neuropathic pain. In conclusion, these cases demonstrate the effectiveness of peripheral nerve stimulation of the thoracic paravertebral plexus in the long-term management of refractory neuropathic pain. They also serve to underline the importance of clinical awareness in order to improve patient safety. Key words: Peripheral nerve stimulation, thoracic paravertebral plexus, persistent post surgical pain, neuropathic pain, pneumothorax