This procedure involves using imaging to guide the drainage of spinal cord cysts, which occur rarely and may cause symptoms such as pain or loss of movement or sensation.

The National Institute for Health and Clinical Excellence is examining therapeutic percutaneous image-guided aspiration of spinal cord cysts and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about therapeutic percutaneous image-guided aspiration of spinal cord cysts.

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• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

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: 27 March 2007
Target date for publication of guidance: June 2007

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

Clinicians wishing to undertake percutaneous image-guided aspiration of spinal cord cysts should ensure that patients understand the uncertainty about the procedure’s benefits and that subsequent interventions may be necessary, and provide them with clear written information. In addition, use of the Institute’s information for patients (‘Understanding NICE guidance’) is recommended (available from www.nice.org.uk/IPGXXXpublic info). [[details to be completed at publication]]

There are several types of spinal cord cyst, all of which are rare. Tarlov or perineural cysts affect nerve roots, most commonly in the sacral region of the spine. The majority are asymptomatic, but they may occasionally cause symptoms such as radicular pain or urinary dysfunction. Arachnoid cysts develop as a result of defects of the dura, usually in the thoracic region of the spine. They can cause radicular pain or loss of sensory or motor function. Spinal echinococcal cysts are a rare feature of hydatid disease, and may also cause radicular pain or loss of neurological function.

Painful spinal cysts are often managed conservatively with analgesics. Open surgery to drain or remove cysts may be indicated if pain is refractory to medical therapy, or if there is a threat of permanent neurological impairment.

The evidence available is from small case series. In a case series of three patients with sacral perineural cysts, two experienced pain relief for up to 3 weeks and one for several weeks (number not stated). Case reports of two patients, one with an arachnoid cyst and one with spinal hydatid cysts, reported that image-guided aspiration rendered each patient asymptomatic during follow-up of 1 year. A case report of a patient with a Tarlov cyst reported that aspiration produced immediate pain relief; however, pain recurred after five days and the patient underwent open decompression.

The Specialist Advisers did not raise concerns about the efficacy of this rare procedure.

Only one case report, of a patient whose spinal hydatid cysts were aspirated under CT guidance, reported on safety outcomes. The patient tolerated the procedure well, with no allergy or anaphylaxis. For more details, refer to the sources of evidence (see appendix).

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

• 'Interventional procedure overview of therapeutic percutaneous image-guided aspiration of spinal cord cysts', January 2007.