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NATIONAL INSTITUTE FOR CLINICAL EXCELLENCE

Interventional Procedure Consultation Document

Direct C1 lateral mass screw for cervical spine stabilisation

The National Institute for Health and Clinical Excellence is examining direct C1 lateral mass screw for cervical spine stabilisation 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 direct C1 lateral mass screw for cervical spine stabilisation.

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  • The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.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: 26 July 2005
Target date for publication of guidance: November 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 on the safety and efficacy of direct C1 lateral mass screw for cervical spine stabilisation appears adequate to support the use of this procedure, provided that the normal arrangements are in place for consent, audit and clinical governance.

1.2

This procedure should only be performed in specialist units where surgery of the cervical spine is regularly undertaken.

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2 The procedure
2.1 Indications
2.1.1 Atlantoaxial instability (excessive movement between the first and second cervical vertebrae) can be caused by trauma, malignancy and by inflammatory or congenital defects. It can present with local pain, but if the spinal cord is compressed symptoms such as clumsiness, lack of coordination, difficulty walking and rarely paralysis or death may occur. Treatment is by stabilisation of the C1 on to the C2 vertebra.
2.1.2

Traditional methods of atlantoaxial fusion involve the use of wires and bone grafts, but these require external support in the post-operative period, including the use of halo devices. Methods of rigid fixation by transarticular screws between C1 and C2 have been described which do not require external fixation, but these procedures are not appropriate for every patient.

2.2 Outline of the procedure
2.2.1

Under general anaesthesia, the patient is placed in the prone position and standard posterior exposure of the cervical spine is performed. Screws are inserted into the lateral masses of C1 and fixed by rods corresponding to screws in the lateral masses or pedicles of C2. The posterior arch of bone compressing the spinal cord may be removed. An onlay graft of bone permits a permanent fusion between C1 and C2.

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2.3 Efficacy
2.3.1 The primary endpoint in the literature was successful fusion. In two case series of 37 and 160 patients and one case report, immobilisation of C1 upon C2 was achieved in all patients.
2.3.2 In a case series of 157 patients, clinical and neurological recovery was documented in 100%, but assessment measures were not described.
2.3.3

A case series investigating a lateral mass and plate system reported that 6% (9/157) of procedures could not be completed due to inadequate exposure of the atlantoaxial region. For more details refer to the sources of evidence (see Appendix).

2.3.4

Specialist Advisors considered this to be a variation on existing fusion techniques.

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2.4 Safety
2.4.1

In two case series of 157 and 37 patients, there were no reports of implant failure. No vertebral artery injuries occurred in case series or case reports where safety outcomes were reported.

2.4.2 In a case series, sensory loss in the distribution of the C2 nerve root was reported by 11% (18/157) of patients undergoing screw and plate fixation. In another case series, deep wound infection was reported in 3% (1/37) of patients. In a further case series, six screws were found to be penetrating more than 4 mm from the anterior cortex of C1 but with no clinical complications. One screw was found to be broken at 18 months' follow-up. For more details refer to the sources of evidence (see Appendix).
2.4.3 Specialist Advisors stated that potential adverse events include haemorrhage from the vertebral venous plexus and screw failure or loosening. Less common but more serious complications may include injury to the vertebral artery and spinal cord injury caused by screw misplacement.
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2.5 Other comments
2.5.1 The Committee recognised that the evidence on this procedure was limited, but it was considered sufficient in the context of conditions requiring treatment.
2.5.2 These recommendations are based on evidence from studies using two different techniques - the plate system and the more recent polyaxial screw and rod systems.
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Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
July 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 direct C1 lateral screw procedure for cervical spine stabilisation, February 2005

Available from: www.nice.org.uk/ip293overview