The National Institute for Health and Clinical Excellence is examining interspinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine and will publish guidance on their 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 procedures. The Advisory Committee has made provisional recommendations about interspinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine.
This document summarises the procedures 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 these procedures. 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• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedures in the NHS in England, Wales and Scotland.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: 20 December 2005
Target date for publication of guidance: March 2006

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

Current evidence suggests there are no major safety concerns associated with interspinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine, but evidence of efficacy is limited and is confined to the medium and short term. These procedures should only be used in the context of special arrangements for consent, audit and research.

Clinicians wishing to undertake interspinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine should take the following actions.

• Inform the clinical governance leads in their Trusts.
  
• Ensure that patients understand that the procedure is not curative, and that further surgery may be needed. Patients should be provided with clear written information. In addition, use of the Institute's Information for the public is recommended (available from www.nice.org.uk/IPGXXXpublicinfo [details to be available at publication]).
  
• Audit and review clinical outcomes of all patients having interspinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine.
  

Publication of long-term efficacy data will be useful. The Institute may review the procedures upon publication of further evidence.

Lumbar spinal stenosis is a narrowing of the spinal canal in the lower part of the back. Unlike disc rupture, lumbar spinal canal stenosis does not normally cause pain in the legs at rest. Characteristically, discomfort in the form of nerve pain, tingling, numbness, or sometimes weakness, occurs when standing or walking any distance (extension), and is relieved by sitting or leaning forwards (flexion). Because this is a degenerative condition, spontaneous resolution is uncommon, and persistence of symptoms, or progressive reduction of standing time and walking distance is common.

The patient is positioned with the spine flexed, and the operative level (or levels) is confirmed by X-rays. A midline incision is made over the appropriate spinal level and deepened to display the spinous processes and their intact joining (interspinous) ligament. The blocking device is sized and positioned in the space between the flexed spinous processes.

A multicentre randomised controlled trial (RCT) compared interspinous implants with non-surgical care in patients with or without back pain, but with leg pain relieved by flexion and CT- or MRI-confirmed spinal stenosis. At 2 year' follow-up there was a 45% improvement in symptom severity from baseline in patients who had the implants, compared with a 7% improvement in the control group (p < 0.001). Physical function scores improved by 44% in patients treated with an implant whereas the scores for those treated medically deteriorated by 0.4% (p < 0.001).

The Specialist Advisors noted that, given the fluctuating symptoms associated with this condition, the assessment of outcomes in clinical studies may be unreliable. Some Advisors questioned the long-term efficacy of the procedure.

In an RCT, 6% (5/88) of patients treated needed re-operation during the first year after implantation. At 2 years' follow-up, there had been one case in 100 patients who had undergone interspinous implantation of each of the following: respiratory distress, ischaemic episode, pulmonary oedema, wound dehiscence, wound swelling, haematoma, and incision pain. There was one incident each of implant misplacement, implant migration, spinous fracture, and increased pain at the implant level. For more details, refer to the sources of evidence (see Appendix).

The Institute is developing guidance on non-rigid stabilisation techniques for the treatment of low back pain (www.nice.org.uk/ip_306).

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

• Interventional procedure overview of interspinous distraction procedures for spinal stenosis causing neurogenic claudication in the lumbar spine, July 2005.

Available from: www.nice.org.uk/ip191overview