Duroplasty for Injured cervical Spinal Cord with Uncontrolled Swelling (DISCUS): a randomised controlled trial

RESEARCH QUESTION: After severe traumatic spinal cord injury (TSCI), does the addition of dural decompression to bony decompression (includes laminectomy) improve muscle strength in the limbs at 6 months, compared with bony decompression alone?

BACKGROUND: TSCI is a devastating condition that affects about 1,000 people in the UK annually. Most remain disabled, tetraplegic or wheelchair bound and are dependent on carers with significant cost to patients, carers and the NHS. Surgery aims to reduce spinal deformity, stabilise the spine and achieve bony decompression of the cord. To date, no treatments have been shown to improve outcome.

AIMS / OBJECTIVES: The primary aim is to determine if, in patients with acute, severe TSCI, the addition of dural decompression to bony decompression improves muscle strength. We hypothesise that, after TSCI, the cord swells and is compressed against the dura. Secondary objectives are to assess patient impact i.e. functional outcomes, health related quality of life (HRQoL), complication rates and mortality.

Mechanistic sub-studies aim to determine if the addition of duroplasty improves cord perfusion, reduces cord ischaemia and cord inflammation.

METHODS: This is a prospective, phase III, multicentre randomised controlled trial (RCT). We aim to recruit 222 adults with acute, severe cervical TSCI (American spinal injuries association Impairment Scale (AIS) grade A, B or C) who will be randomised 1:1 to undergo bony decompression alone versus bony decompression with duroplasty. Patients and assessors will be blinded to study arm.

The primary outcome is change in AIS motor score (AMS) at 6 months compared with admission (Delta-AMS); secondary outcomes will assess function (grasp, walking, urinary + anal sphincters), HRQoL, complications, need for further surgery and mortality, assessed at baseline, 3 months, 6 months and 12 months from randomisation. A subgroup of 50 patients (25 per arm) will also have observational monitoring from the injury site using a pressure probe (intraspinal pressure ISP, spinal cord perfusion pressure SCPP) and microdialysis (MD) catheter (cord metabolism: tissue glucose, lactate, pyruvate, lactate-to-pyruvate ratio (LPR), glutamate, glycerol); cord inflammation: tissue chemokines/cytokines. Patients will be recruited from the 26 UK major trauma centres (MTCs).

TIMELINES FOR DELIVERY: The study duration is 72 months and includes 6 months set-up, 48 months recruitment, 12 months to complete follow-up and 6 months for data analysis and final reporting of results. There will be a formal stop/go review at month 15 (after 9 months of recruitment) to ensure a minimum of 4 sites have been opened and 8 patients randomised. If these targets are met, the trial will recruit for a further 36 months. Data from the pilot will be included in the final analysis.

ANTICIPATED IMPACT AND DISSEMINATION: It is anticipated that the addition of duroplasty to standard of care will improve muscle strength in patients; this has obvious benefits for patients and their carers as well as substantial gains for the NHS and society including economic implications. If this RCT shows that the addition of duroplasty to standard treatment is beneficial, it is anticipated that duroplasty will become standard NHS care in all 26 UK MTCs.

Participants will be informed of study findings via the Surgical Intervention Trials Unit (SITU) website and the Spinal Injuries Association (SIA).