The Duration of External Neck Stabilisation (DENS) study is a randomised controlled trial comparing early removal of a hard collar with treatment in a hard collar for 12 weeks in older or frail adults with odontoid (dens) fractures. The primary outcome measure is QoL assessed using the EQ-5D-5L at 12 weeks following injury. The aim of the study is to determine whether management without a collar improves outcome, compared to management with a collar. Cost efficiency will be assessed over the observed 6 months using standard NICE reference case methodology.

This is a non-blinded randomised controlled trial with nested qualitative research comparing early removal of a hard collar (intervention) with treatment in a hard collar for 12 weeks (standard care) in older or frail adults with odontoid peg fractures. The primary outcome measure is QoL assessed using the EQ-5D-5L at 12 weeks following randomisation.

Potentially eligible participants will be assessed in the ED, or on hospital admission. Assessment of eligibility, recruitment and randomisation should take place as soon as possible (target within 48 hours) after injury. Patients with incapacity who are unable to give informed consent may still be recruited.

Exceptionally, patients who have not been assessed for eligibility at the time of their acute admission, or who were assessed but in whom there was some other delay to study inclusion, may be recruited up to 3 weeks post-injury.

Those who take part will be randomised to continuing in a hard collar for 12 weeks or to early removal of the hard collar.

During the pilot phase, a subset of patients, caregivers and health professionals will be interviewed.

In current standard care, patients with suspected cervical spine injuries are usually (but not universally) immobilised with non-padded trauma collars or blocks, possibly on spinal boards, on admission to the ED. Early removal of this emergency immobilisation and replacement with a padded hard collar (e.g. Miami J, Aspen, Philadelphia) as per standard care is desirable for skin care and comfort. In this study this immobilisation replacement will take place as usual with guidance from ED and spinal service (orthopaedic/ neurosurgical), on-call staff, according to local protocols. This avoids any delay in removal of emergency immobilisation that might be caused by trial procedures to establish eligibility or consent that could lead to poorer quality of care for participants.

All participants will undergo standard care investigations for suspected cervical spine fracture. This includes CT of the cervical spine to identify fractures, and a full neurological examination and assessment. All participants will be discussed with the on-call spinal (neurosurgical/orthopaedic) service unit as per usual protocols. All participants will be given adequate analgesia for neck pain. Participants will only be enrolled following a consultant radiologist report of an odontoid fracture and confirmation from the local spinal consultant that randomisation to non-operative management with or without a hard collar is appropriate.

Inclusion Criteria:

• Rockwood clinical frailty scale (CFS) of 5 or more, or aged 65 years or over;
• A recent odontoid fracture (type I-III) (within 3 weeks) as assessed on CT, irrespective of degree of fracture angulation, displacement or canal narrowing;
• History of recent trauma (within 3 weeks)
• Determined by spinal consultant (or delegated registrar) as suitable for standard care 12-week treatment with hard collar and for randomisation to treatment without a collar
• Recruited within 3 weeks of injury

Exclusion Criteria:

• New neurological deficit (numbness / weakness) attributable to fracture;
• Assessed as unable to tolerate a hard collar e.g., dystonia, fixed deformity;
• Additional (non-odontoid) cervical spine fracture not suitable for management without a hard collar;
• Underlying condition potentially leading to spinal instability, e.g., ankylosing spondylitis, diffuse idiopathic skeletal hyperostosis (DISH);
• Fracture suspected to be older than three weeks at the time of assessment;
• Consultant spinal surgeon determines fracture requires surgical treatment or is otherwise unsuitable for non-surgical treatment with or without a hard collar;
• If not expected to survive to hospital discharge based on concomitant injuries or illnesses.

Anonymised patient-level data will be available on reasonable request to the Chief Investigator (paul.brennan@ed.ac.uk). The trial protocol and statistical analysis plans will be published and available prior to trial completion.

The Protocol (and consent form) has been submitted to the British Medical Journal - BMJ Open and will be available once their review is complete.

The SAP will be available prior to trial completion.

Available on reasonable request to the Chief Investigator (paul.brennan@ed.ac.uk) as assessed by the study management group