Position and anatomical landmarks
During the entire procedure, the patient must be able to communicate and be able to respond to questions appropriately. A sufficient number of supporting nursing staff should be present for placing and maintaining the patient in the correct position and for changing the patient's position during the procedure.
The procedure must be performed under full sterile operating theatre conditions. An intravenous line is necessary for administering medication. Precautionary measures for reanimation should be considered.
The patient lies in the prone position on the operating table with a pillow under the pelvis to flatten the lumbar lordosis.
Procedure
The area is extensively disinfected. The skin is anaesthetised with local anaesthetics. A spinal needle (22-G) is placed at a median level in the intervertebral space of L5/S1. The spinal needle is carefully advanced until fluid appears. A phenol solution (6% in glycerine) in an accurate calibrated 2 ml syringe is connected to the needle.
The nurses are asked to lean back at an angle of 45°, in such a way that the back makes an angle of 45° with the horizontal line. Thereafter, the phenol solution is injected into the intrathecal space at an amount of 1 ml per five minutes. If the patient experiences sensory changes in the legs or buttocks, the administration of the phenol solution should be stopped immediately. In some cases, it is necessary to administer the phenol solution up to a total volume of maximally 1.5 ml.
The spinal needle is removed and the patient remains sitting at a 45º backward angle for six hours. Regular monitoring of blood pressure is necessary. The course of the VAS pain is score recorded.
Only during the days following the procedure can an analgesic effect be expected, illustrated by the possibility to decrease the pain medication.
Complications
- Sensory loss with dysaesthesia in the legs or buttocks.
- Loss of bladder and/or anal sphincter function.
- Muscle weakness in the legs.