Automated percutaneous mechanical lumbar discectomy

Lumbar radicular pain, also known as sciatica, refers to pain that begins in the lower back and radiates down the leg. It is commonly caused by a herniated (or prolapsed) lumbar intervertebral disc. The herniation is a result of a protrusion of the nucleus pulposus through a tear in the surrounding annulus fibrosus. The annulus fibrosus may rupture completely, resulting in an extruded disc, or may remain intact but stretched, resulting in a contained disc prolapse. This may then compress one or more nerve roots, causing pain, numbness or weakness in the leg.

Conservative treatments include the use of analgesics, non-steroidal anti-inflammatory medicines, physical therapy and hot or cold compresses. Epidural injections of corticosteroid may also be used. Surgery to remove disc material may be considered if there is nerve compression or persistent symptoms that are unresponsive to conservative treatment.

Alternative surgical treatments include open discectomy and minimally invasive microdiscectomy.

Automated percutaneous mechanical lumbar discectomy is performed using local anaesthetic with or without conscious sedation. Under fluoroscopic guidance, a cannula is placed centrally within the disc using a posterolateral approach on the symptomatic side. A probe connected to an automated cutting and aspiration device is then introduced through the cannula. The disc is aspirated until no more nuclear material can be obtained.

In a randomised controlled trial (RCT) of 71 patients, 29% (9 out of 31) had a successful outcome after automated percutaneous lumbar discectomy, compared with 80% (32 out of 40) of patients after microdiscectomy (p<0.001). In a second RCT, 41% (7 out of 17) of patients had an 'excellent' or 'good' outcome after automated percutaneous lumbar discectomy, compared with 40% (4 out of 10) of patients after conventional discectomy. A third RCT compared automated percutaneous lumbar discectomy with chemonucleolysis and found that significantly more patients had a successful result after chemonucleolysis (61% [44 out of 72] versus 43% [30 out of 69], p<0.05).

Two large case series reported that 68% (707 out of 1,047) and 82% (1,216 out of 1,474) of patients had an 'excellent' or 'good' result at 6 months and 1 year, respectively. A third case series reported an overall success rate of 45% (52 out of 115) after a mean follow-up of 55 months. In two further case series reports, 94% (47 out of 50) and 52% (95 out of 182) of patients were satisfied after mean follow-ups of 6 months and 2.5 years, respectively. For more details, refer to the overview.

The Specialist Advisors stated that there was some uncertainty about the efficacy of the procedure.

Few complications were reported. Three studies reported discitis in between 0.2% (2 out of 1,146) and 1% (2 out of 182) of patients. Two studies reported haematoma in 0.1% (1 out of 1,146) and 1.4% (1 out of 69) of patients. Other complications included back muscle spasms, minor bleeding, minor radicular injury and vasovagal syncope. For more details, refer to the overview.

The Specialist Advisors stated that vascular and nerve damage, discitis and infection were potential adverse effects of the procedure.