Overview — Spinal Investigations

No single test tells the whole story of a spinal problem. Each investigation looks at a different aspect — the shape and alignment of the bones, the state of the discs and nerves, the density and strength of bone, the activity of muscles and nerves, or the presence of inflammation, infection or tumour. This section explains the main spinal investigations in plain English: what each one is, how it works, what to expect, and why it is useful. The aim is to help you understand the tests you may be offered, not to replace advice about your own care.

The purpose of an investigation is to answer a specific question that will change what happens next — not simply to scan everything that can be scanned. Different tests suit different questions. X-rays and CT show bone and alignment; MRI shows the discs, nerves and spinal cord; DEXA measures bone density; nerve conduction studies and EMG assess how nerves and muscles are working; nuclear medicine scans such as SPECT-CT show where bone is active; and diagnostic injections test directly whether a specific structure is causing pain. The right test is the one that best answers the question at hand.

Timing matters as much as choice. For most people with new back pain, a scan in the first few weeks does not change the plan and can even be misleading, because harmless, age-related changes are extremely common in healthy spines and may be mistaken for the cause of pain. Investigations are therefore usually timed to clinical need — for example when there are specific warning signs, when symptoms persist despite initial treatment, or when a decision about a procedure has to be made. Each test page in this section describes what the experience is actually like.

The value of any investigation lies in interpreting it alongside your symptoms and examination, not in isolation. A finding on a scan only matters if it fits the clinical picture, and a normal test does not always mean nothing is wrong. Choosing the right test, at the right time, and reading it in context is what allows a clear diagnosis and a treatment plan tailored to the individual.

• —NICE — Low Back Pain and Sciatica in Over 16s (NG59)
• —Royal College of Radiologists — iRefer: Making the Best Use of Clinical Radiology
• —British Association of Spine Surgeons (BASS)

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.