NATIONAL INSTITUTE FOR CLINICAL EXCELLENCE

Interventional Procedure Consultation Document

Prosthetic intervertebral disc replacement in the cervical spine

The National Institute for Health and Clinical Excellence is examining prosthetic intervertebral disc replacement in the cervical spine and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about prosthetic intervertebral disc replacement in the cervical spine.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

  • comments on the preliminary recommendations
  • the identification of factual inaccuracies
  • additional relevant evidence.

Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute will follow after the consultation period ends is as follows.

  • The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
  • The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.

For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual).

Closing date for comments: 21 June 2005
Target date for publication of guidance: September 2005
 

 
Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

 
1 Provisional recommendations
 
1.1 Current evidence suggests that there are no major safety concerns about prosthetic intervertebral disc replacement in the cervical spine, and there is limited evidence of short-term efficacy. Clinicians wishing to undertake this procedure should take the following actions.
  • Ensure that patients understand the long-term uncertainties about the procedure and the alternative treatment options. In addition, use of the Institute's Information for the public is recommended.
  • Audit and review clinical outcomes of all patients having prosthetic intervertebral disc replacement in the cervical spine.
     
 
1.2 This procedure should only be performed in specialist units where surgery of the cervical spine is regularly undertaken.
 

 
2 The procedure
 
2.1 Indications
 
2.1.1 This procedure can be used for patients with acute disc herniation or cervical spondylosis. In these conditions, nerve root or spinal cord compression may cause symptomatic radiculopathy or myelopathy.
 
2.1.2 Conservative treatment options for acute radicular pain include analgesic medication, rest, supervised physical therapy and local injections.
2.1.3 Surgical intervention is reserved for patients with neurological threat, or for patients whose symptoms fail to settle with conservative care. The standard treatment is surgical decompression of the nerve root or spinal cord by cervical discectomy, with or without fusion (using an iliac crest autograft or a variety of pre-formed spacers or cages). Following cervical discectomy, a proportion of patients re-present with progressive spondylosis requiring surgical treatment at adjacent cervical segments.
 
2.2 Outline of the procedure
 
2.2.1 Artificial intervertebral discs have been developed to act as functional prosthetic replacements for intervertebral units. A number of devices have been developed for the cervical spine. Under general anaesthetic, the patient is placed in the supine position. The anterior cervical spine is exposed, and after standard decompression of the neural elements, an artificial disc prosthesis is placed between the vertebrae.
 
2.3 Efficacy
 
2.3.1 Many studies relied on patients' self-reported outcomes to determine the clinical efficacy of prosthetic disc implants.
 
2.3.2 In two randomised controlled trials with follow-up of 6 months and 24 months (n = 13 and n = 9 respectively), neck and arm pain scores and quality of life indices all improved, with no statistically significant difference in outcomes between patients treated with artificial disc implants and those treated by fusion surgery. One case series of 7 patients found significant improvements in arm and neck symptom scores and neck disability index assessment at 6 months, compared with preoperative values.
 
2.3.3 The largest case series available reported an improvement in clinical evaluation of motor strength and sensory signs, and reported patient self-evaluation of symptoms as 'excellent' in 65% (32/49) of patients having single-level disc replacement, and 77% (20/26) of patients having surgery at two levels.
2.3.4 The range of motion in the treated spinal segment was reported to be well preserved in those studies which included this outcome measure. One case series reported motion of more than 2 degrees in 93% (43/46) of patients treated. Maintenance of a 5.9 degree range of motion at 12-month follow-up was confirmed by radiographic assessment in the prosthetic disc arm of a randomised controlled trial (n = 27). For more details, refer to the sources of evidence (see Appendix).
2.3.5 The Specialist Advisors commented that longer-term data were required to compare the results with those of spinal fusion.
2.4 Safety
 
2.4.1 There were no reported incidents of device failure in 100% (27/27) of patients in the prosthetic disc arm of a randomised control trial, or among 13 patients in a case series. Device migration was noted in 2% (2/103) of patients undergoing prosthetic cervical disc implant in a case series, although no migration was greater than 3.5 mm from the initial implant site and none was associated with neurological symptoms.
 
2.4.2 In a large case series of patients undergoing prosthesic implant, reintervention was required in 3% (3/103) of patients (two patients required treatment for residual symptoms, and one patient required evacuation of a haematoma).
2.4.3 Other adverse events reported included transient hoarseness in 13% (2/15) of patients, moderate dysphagia in 4% (1/27) and recurrent laryngeal nerve palsy in 4% (1/27). For more details, refer to the sources of evidence (see Appendix).
2.4.4 The Specialist Advisors noted that theoretical adverse events included nerve root compression with device migration and airway obstruction with anterior displacement. They also noted that device failure may cause spinal cord damage.
 

 

Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
June 2005

Appendix: Sources of evidence
 
The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

Interventional procedure overview of prosthetic intervertebral disc replacement of the cervical spine, February 2005
 

Available from: www.nice.org.uk/ip265overview