Epiduroscopy was developed in the 1990’s. A fibre optic camera is inserted through the sacral hiatus into the lower epidural space, and is then guided upwards towards the lower lumbar discs and nerve roots.
Epiduroscopy has two main uses:
1) Releasing epidural adhesions where they are causing chronic sciatica. Adhesions can form around the lower lumbar nerve roots after decompressive surgery for disc disease, or after a bad bout of inflammatory sciatica in the absence of surgery. Epidural adhesions can usually be identified on an enhanced MRI scan using intravenous gadolinium. They also cause uneven spread of X ray contrast when performing an epidurogram.
2) Injecting mixtures of local anaesthetic and depot steroid around inflamed nerve roots when epidural injections / nerve root blocks have been unsuccessful. The presence of adhesions can prevent epidurally injected drugs from reaching the inflamed nerve roots.
Epiduroscopy is not advised in the presence of altered coagulation (warfarin, liver or haematological disease). The elderly do not tolerate the procedure well due to the rise in intra-cerebral pressure caused by the saline flushing system.
The procedure is performed in the face-down position, under intravenous sedation and local anaesthesia, whilst using X-ray screening in an operating theatre to minimise infection.Local anaesthetic is injected in and around the sacral hiatus to numb the area. A small needle is inserted through the sacral (caudal) hiatus into the epidural space. Through this needle is then passed a fine metal guide wire. The small needle is then removed leaving the guide wire in place in the epidural space. A series of dilators are then passed over the guide wire until the sacral membrane will accept a sheath cannula (see diagram above). Once the sheath is in place, the guide wire is removed. A steerable catheter attached to a fibreoptic epiduroscope is then inserted through the centre of the sheath until it enters the epidural space. Passage of the steerable catheter is enhanced by using a saline flush system attached to a side port on the sheath. The fibreoptic epiduroscope is then advanced upwards using X-ray guidance, until it reaches the area where epidural adhesions have been found on an MRI scan. Once in the correct area, epidural adhesions can be gently broken down using the epiduroscope tip. Afterwards, local anaesthetic and depot steroid can be injected around any inflamed nerve roots in the area.
1) Direct Nerve Root Injury is possible during epiduroscopy, but is minimised by having the patient awake and able to verbally communicate with the operator.
2) Dural Tears can sometimes occur caused by the epiduroscope making a small hole in the dural membrane. This causes a Post Dural Puncture (Spinal) Headache, which usually settles in a few days, but may continue to be problematic for several weeks in a minority of cases. In the UK, spinal headaches are treated by performing an epidural blood patch to seal the hole.
3) Macular Haemorrhages or bleeding in the internal layers of the eye, can occur when excessive volumes of saline flush are used during the procedure. Excessive saline causes an acute rapid rise in intra-cerebral pressure, leading to haemorrhage in the eyes. These can be avoided by limiting the volume of flush used during the procedure.