PERCUTANEOUS NEUROLYSIS OF THE SPLANCHNIC NERVES
Percutaneous chemical neurolysis releases patients from the restraints and the adverse effects of opiates whilst avoiding a surgical neurolysis.
The solar plexus and the splanchnic nerves convey, in parallel to the vegetative nerve fibres of the sympathetic nerve system, sensitive fibres of gastric, pancreatic, hepatic and mesenteric origin.
Percutaneous neurolysis can treat pain resulting from the activation of these nerve structures. The splanchnic nerves are located on the same level as the coeliaque plexus but circulate behind the pillars of the diaphragm, in front of the vertebrae.
The equipment used is simple : a fine standard Chiba or spinal type needle from 21,5 to 22 G (reduction of the risk of retroperitoneal haematoma), xylocaïne 0,5%, alcohol at 96 % and diluted iodized contrast products.
The thinness of the needle and its flexibility are responsible for deviations which can sometimes be large, especially in the parietal muscular compartment.To limit these deviations, the coaxial technique is very useful. Indeed, an 18 G needle 4 cm long placed in the muscular wall in the correct direction, makes the approach easier.
The percutaneous approach is posterieur-lateral. The interest of this technique lies in the direct access to the retroperitonal region, avoiding the abdominal organs (as opposed to coelic neurolysis).
This technique was especially used under X-ray guidance with T11 anatomical location. Today it is no longer lawful to carry out this treatment without SCAN location in order to reduce possible complications to a minimum. A separate percutaneous access is necessary to treat the elements of the controlateral splanchnic nerve.
The patient is in procubitus,
many control cuts are necessary. Once the needle is in place behind the
pillar of the diaphragm and retroaortic, 1 to 2 ml of contrast product
is injected, as for the fore tract, confirming the good position of the
point of the needle point.
minor effects : giddiness, cephalgia, tachycardy, transitory hypoTA, a metallic taste.
major effects : convulsion, coma, circulatory collapse.
After the ethanol injection, the temperature increases in the higher part of the abdomen.This is a side effect which is also an indicator of the success of the treatment primarily for coelic neurolysis. Blood pressure can fall, but in most cases, the drop is moderate.
Scanographic control makes it possible
to avoid intravascular injections and lesions of neighbouring bodies.
But any lump syndrome at this level
can be at the origin of the pain (coelio-mesenteric metastatic adenopathies).
Among cancer patients, the pains are caused by the compression of or the
invasion of the nerve structures by the tumour.
Thanks to the use of thin needles, the contra-indications are very rare.
The neurolysis must be practised with prudence among hypotensive patients and is contra-indicated for subjects in hypovolemy.