Gap analysis
| Domain | Outcome | Interpretable measurement instrument(s) identified |
| Adverse events | Death | |
| Surgical adverse events | 0 (N=55) | |
| Economic impact | Cost of care | |
| Employment status | 0 (N=5) | |
| Life impact | Dependence | |
| Falls | 0 (N=173) | |
| Fatigue | 1 (N=207) | |
| Mental health | ||
| Mobility | ||
| Neuromuscular function | Arm strength | |
| Balance | ||
| Bladder function | ||
| Faecal incontinence | 0 (N=308) | |
| Finger/hand dexterity | ||
| Finger strength | ||
| Grip strength | ||
| Leg strength | ||
| Muscle tone and spasticity | 0 (N=39) | |
| Neck mobility | ||
| Sensation | ||
| Pain | Location | |
| Intensity | ||
| Pain control | ||
| Perception | ||
| Radiology | Adjacent segment degeneration | 0 (N=69) |
| Cervical spine alignment | 0 (N=24) | |
| Cord compression | 0 (N=69) | |
| Cord signal change | 0 (N=24) |
Elements with at least one interpretable instrument (see phase 2.1) are shaded green and will be published separately. Targeted searches of MEDLINE were performed for the remaining elements (ie, ‘gaps’, unshaded, see phase 2.2). For gaps within the domain of pain (shaded blue), the resources aggregated by Initiative on Methods, Measurement and Pain Assessment in Clinical Trials were deemed sufficient.79 The number of articles (N) screened is indicated for each gap. Notably, only one suitable resource was identified for ‘fatigue’.55