Phantom Pain and Stump Pain

Definition

Phantom pain and stump pain may appear after limb amputation. Phantom pain refers to pain felt in a limb even though it has been removed. It is a frequent occurrence, affecting 50 to 80% of all amputees. In some cases phantom pain eventually fades away. Phantom pain syndrome has multiple causes and no effective treatment is available to date. Pharmacological treatment is administered as a rule, even though no specific medication has been developed to treat phantom pain. Patients are prescribed analgesics, anticonvulsants (such as pregabalin (Lyrica) or gabapentin), and antidepressants. However, depending on the dosage, this type of medication may cause pronounced adverse side effects.

Treatment

The following methods are used: 1. Transcutaneous electrical nerve stimulation (TENS). 2. Electroconvulsive therapy (ECT).

Surgical treatment includes medullary stimulation, intrathecal systems placed under the meninges, and cerebral stimulation. None of these methods yields satisfactory results.

To overcome the shortcomings of these techniques, Prof. Possover implements the «LION» procedure, which employs laparoscopy to implant an electrode on the trunk of the sciatic nerve. This procedure makes it possible to stimulate the entire sciatic nerve, opening up unprecedented opportunities for treatment. Indeed, neuromodulation is only effective if the electrode is positioned upstream of the lesion (thus interfering with the transmission of pain signals in the direction of the brain) and if all the nerve fibres that are responsible for this signal transmission are stimulated by the electrode.

The sciatic nerve is formed by the fusion of several sacral nerve roots. As it exits the small pelvis, the sciatic nerve produces several nerve branches, such as the gluteal nerves and the pudendal nerve. Only a small segment of the sciatic nerve in the pelvic cavity can be targeted to reach all its nervous fibres simultaneously. This segment, measuring approximately 1 cm, is located deep inside the small pelvis. Laparoscopy is the only technique that allows us to implant an electrode at that position with relative ease. Thus, all nerve signals emanating from the lower limbs can be controlled at the level of the small pelvis, before they reach the spinal cord. This technique is suitable to treat both phantom pain and stump pain. Moreover, there are generally no adverse side effects and all other perceptions and motor functions remain intact.

Benefits and Risks

Laparoscopy carries fewer risks of complications than the other techniques. Abdominal or transgluteal incisions are more hazardous because the regions that are operated upon contain numerous large vessels. Finally, transgluteal surgery does not allow the stimulation of the gluteal nerves.