2 The procedure
2.1.1 Symptomatic cervical disc prolapse occurs when part of the intervertebral disc protrudes into the spinal canal and impinges on a nerve root or the spinal cord. The protruding disc may compress one or more nerve roots, which may cause neck and shoulder pain, radicular arm pain, weakness and numbness. Many mild episodes settle spontaneously but, in severe cases, serious neurological sequelae may occur.
2.1.2 Conservative treatments include analgesics and non-steroidal anti-inflammatory medication and physical therapy. Epidural steroid injections can also be used. Surgery to remove disc material is considered if there is evidence of nerve or spinal cord compression causing neurological loss or persistent symptoms that are unresponsive to conservative treatment. Surgical treatment options include open surgical decompression by discectomy with or without grafting or disc replacement.
2.2.1 The procedure is carried out with the patient under general anaesthesia and with endoscopic guidance. A small retractor port is inserted into the anterior neck to expose the disc. All or part of the disc material is removed using a combination of laser to ablate disc material and to shrink and contract the disc further (laser thermodiskoplasty), and curettes, microforceps and a discotome to decompress the nerve root or spinal cord.
Sections 2.3 and 2.4 describe efficacy and safety outcomes which were available in the published literature and which the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview.
2.3.1 A case series of 111 patients treated by percutaneous endoscopic laser cervical discectomy reported that 47% (52/111) of patients were classified as having an 'excellent' outcome, 33% (37/111) had a 'good' outcome, 8% (9/111) had a 'fair' outcome and 12% (13/111) had a 'poor' outcome (measured by the McNab criteria four-point scale, which ranges from poor [no or insufficient improvement to enable an increase in activities] to excellent [no pain or restriction of activity]) (mean follow-up 49 months).
2.3.2 The Specialist Advisers listed the key efficacy outcomes as pain measured by visual analogue scores for arm and neck pain, disability as measured by the Neck Disability Index, or Oswestry Disability Index and health status as measured by the SF36.
2.4.1 The case series of 111 patients treated by percutaneous endoscopic laser cervical discectomy reported that 3% (3/111) of patients needed additional surgery because of incomplete decompression and 'symptom aggravation' (mean follow-up 49 months).
2.4.2 A case series of 41 patients treated by percutaneous endoscopic laser cervical discectomy reported that vessel compromise because of guide wire positioning occurred in 5% (2/41) of patients; this was related to a jugular vein and a carotid artery (follow-up not stated). Discitis developed in 2% (1/41) of patients, leading to disc space collapse, and was treated by vertebral bone fusion (follow-up not stated).
2.4.3 The Specialist Advisers considered the most important theoretical risk to be heat damage to nerve roots or to the spinal cord, potentially leading to quadriplegia. One Specialist Adviser stated that neurological damage had occurred in a patient as a result of using laser in the lumbar region of the spine.