Cervical Radiculopathy: A Study With Selective Nerve Root Blocks

Cervical radiculopathy is diagnosed by history, clinical examination of the patient and magnetic resonance imaging (MRI) of the cervical spine. In many of the patients undergoing this diagnostic strategy, the nerve root/roots responsible for the radicular pain is difficult to define as clinical examination and MRI investigation does not provide information enough. The information from transforaminal selective diagnostic nerve root blocks with local anaesthetics (SNRB) when used in the cervical spine in patients with radiculopathy was evaluated in two prospective studies including 20 patients with mono segmental disc disease and 30 patients with two segmental disc disease. In another prospective study including nine patients, the contrast spread from three different volumes injected into the foraminal area was evaluated with multi-slice computed tomography. Furthermore, 40 patients were prospectively randomized for treatment with a transforaminal injection of saline and local anaesthetics or steroids and local anaesthetics in treatment of radicular pain. The patients were followed up after three weeks. In the mono-segmental study it was shown that positive response to a selective nerve root block predicted good/excellent surgical outcome in 100% of the patients. In the two segmental degenerated patients it was shown that diagnostic SNRB provided information not given by the MRI and/or clinical examination. The correlation between SNRB and MRI was 60 %, and between SNRB and clinical examination, 28 %. The positive response to the SNRB predicted good/excellent outcome in 82 % of the treated patients. Distribution from transforaminal SNRB was influenced by the injected volume and the foraminal area. Injection into a large foramen created a spread into the spinal canal distant from the injected site with possibility to reach nearby nerve roots. Injection into a narrow foramen created a spread along the vertebral artery with possible spread to other nerve roots. The nerve root above the injected level was more often at risk than the nerve root below and a volume of 0.5 of local anaesthetics is more reliable than 1.5 for diagnostic blocks. No difference was seen when comparing saline/local anaesthetics with steroids/local anaesthetics for the treatment of radiculopathy. Further studies have to be performed to evaluate the need for steroids in such treatment as the steroid component can produce serious complications when injected into spinal blood vessels.