CT-Guided Cervical Nerve Root Block

A CT-guided cervical nerve root block is an injection of local anaesthetic (often with a steroid) placed precisely around a single nerve root in the neck, using a CT scanner to guide the needle. Its purpose is to test — and often to help relieve — pain that travels from the neck into the shoulder or arm along the path of one particular nerve. It is used especially when a scan shows more than one nerve that could be responsible, and it is important to know which one.

Each cervical nerve root supplies a fairly predictable area of the arm, so if numbing one specific root temporarily removes the arm pain, that nerve is strongly implicated. The neck is a delicate region, with important blood vessels and the spinal cord close by, which is exactly why CT guidance is valuable: the detailed, cross-sectional images let the specialist place the needle with pinpoint accuracy and avoid nearby structures. A small amount of contrast is usually used to confirm correct placement before the medicine is given, and the response is then observed.

The procedure takes place in a CT room. You lie on the scanner table, the skin is cleaned and numbed, and the specialist advances the needle in small steps, taking CT images to check its position. You may briefly feel a tingle or a reproduction of your familiar arm pain as the needle nears the nerve, which helps confirm the target. The injection itself is quick. Afterwards the arm may feel numb or heavy for a few hours, and you will usually be asked to note how your pain responds and to arrange to be taken home.

When neck imaging shows several possible sites of nerve compression, identifying the true source is critical, because treatment aimed at the wrong level is unlikely to help. A CT-guided approach brings a high level of precision and safety to testing a single cervical nerve in a crowded, delicate area. The result — read alongside symptoms, examination and scans — can clarify which nerve is responsible and guide what happens next.

• —NICE — Low Back Pain and Sciatica in Over 16s (NG59)
• —Royal College of Radiologists — iRefer: Making the Best Use of Clinical Radiology
• —Faculty of Pain Medicine, Royal College of Anaesthetists — Standards

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.