PERCUTANEOUS NEUROLYSIS OF THE SPLANCHNIC NERVES



 

Mechanism
Technique
Complications		 Indications
Contra-indications

MEDLINE 

 
 
 

MECHANISM

Percutaneous neurolysis represents an alternative to surgical neurolysis in the symptomatic treatment of pain, in particular in the case of cancer patients. 
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.

TECHNIQUE

SCAN provides the ideal imagery technique for the guidance of splanchnic neurolysis.
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.


Bilateral splanchnic Neurolysis

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. 
If cross-duct spreading occurs, the needle will be repositioned.
For the splanchnic neurolysis, 10 ml of ethanol at 96 % is sufficient on each side.

COMPLICATIONS

The intravascular injection of xylocaïne must be avoided by repeated aspiration before the anaesthetic injection. On this subject, the side effects of the passage of the xylocaïne into the  blood circulation can be pointed out at this 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.
Complications such as paraplegia, either by the intrathecal spread of alcohol along the lumbar plexus, or by the lesion of a lumbar artery carrying an Adamkiewicz artery are reported but primarily under scopic control. In the case of cachectic subjects, a transitory ebrious state can be observed.
The abdominal and dorsal pains disappear within a few hours after the treatment.The intestinal motricity  problems disappear quickly in general. Rarer complications, like  chemical peritonitis due to the diffusion of alcohol in the peritoneum, haematuria due to renal puncture, and pneumothorax, are rarer and occur in general with  X-ray guidance.
Scanographic control reduces the number of complications.
 
 

INDICATIONS


The most frequent application remains in abdominal and epigastric pains of neoplasic origin with infiltration and retroperitoneal invasion on the level of the higher mesenteric artery or the coelic trunk and chronic pancreatitis.
In general it is a matter of non redivisible tumours or secondary tumours.
The origin of the neo-formation is often pancreatic, hepato-vesicular or gastroduodenal.
 
 

Bilateral splanchnic Neurolysis (2)

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. 
They are often large tumours which are primarily pancreatic, more rarely gastroduodenal, hepato-vesicular, mesenteric or ganglionic.
 
 

CONTRA-INDICATIONS

They are those common to all punctures : problems of coagulation, infection at the site of puncture, allergy to a drug used (iodine, xylocaïne).
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.
 
 

RESULTS
The success of the treatment is judged by the regression of the pain and the reduction in or the stopping of the antalgic treatment.
This effect is obtained in between 84 and 100 % of the patients affected by a cancer of the pancreas.
The failure of  percutaneous neurolysis is due either to too great an infiltration of the retroperitoneal or parietal tumour activating other nerve systems.
Short-term regression can be explained especially by the progression of the mass of the tumour.
Long-term regression is due to the regeneration of the nerve nets.
The simplicity and security of percutaneous neurolysis guided by SCAN make its repetition possible in the case of failure or regression.