Comment with regard to: Outcomes of a prospective cohort study on peri-radicular infiltration for radicular pain in patients with lumbar disc herniation and spinal stenosis (L. Ng et al.)

Excerpt

In a patient presenting with clear-cut radicular pain, it is tempting to pursue non-surgical therapies directed towards the affected nerve. This would seem to be logical, especially in view of the increasing evidence that the genesis of such pain is not just nerve compression [1]. Amongst the techniques favoured in radicular pain syndromes is the injection of local anaesthetic and steroid around the nerve root, variously called peri-radicular infiltration, paravertebral block or nerve root block, a technique performed by anaesthetists as well as spinal surgeons. Whilst many practitioners can provide anecdotal evidence of efficacy, the literature is of little help: there are no controlled studies of reasonable quality. The study of Ng et al. in this issue is of interest because it does include carefully collected outcome data not only of pain and general function (Oswestry and Low Back Outcome Score), but also of the Dram score (Zung Depression Inventory and Modified Somatic Perceptions Questionnaire), in two cohorts of patients undergoing peri-radicular infiltrations for nerve root pain due either to lumbar disc herniation or spinal stenosis. The data provide details of the outcome that can be expected from the performance of a nerve root injection using a small volume of bupivacaine with 40 mg methyl prednisolone, on pain, distress and general function. Both groups get better, but this is much more marked in the disc herniation group. The improvement seen in the spinal stenosis group is minimal, with only a two-point reduction in ODI and 7 mm on VAS at 6 weeks with some further improvement (to 6 and 12, respectively), on the VAS at 12 weeks. Given that the patients started off with VAS scores of 77 a reduction to 70 after 7 weeks is not satisfactory pain management. It has been estimated that one needs a 13-point change to detect clinically relevant pain relief [3]. …