Post-sacral lateral branch radiofrequency ablation neuritis: The more we know, the less we understand

Dear Editor, We appreciate Dr Silva-Ortiz’s thoughtful comments regarding potential adverse consequences of radiofrequency ablation of the sacral lateral branches (SLBRFA) and agree with his recommendations.1 The targeted sacral lateral branches coalesce to form the middle cluneal nerves, and lesioning these branches—which also supply cutaneous tissues in the back and the posteriomedial buttock—can result in minor cutaneous sensory loss or dysesthesias, commonly termed “post-procedure neuritis.”2 Whereas the minor sensory loss is typically of little clinical significance, post-procedure neuritis can sometimes be quite unpleasant. Accordingly, both a pre-procedure discussion (ie, “informed consent”) and adequate post-procedure surveillance are recommended. The true incidence of neuritis after SLBRFA remains unclear but is likely comparable or even higher than that observed following lumbar medial branch radiofrequency ablation (RFA), considering that it is the lateral (not medial) branches that supply the densely innervated skin, and the greater number of targeted nerves relevant to SLBRFA.3,4 The reported rates depend on diagnostic criteria and surveillance methods; more frequent assessments tend to yield higher incidence estimates.5 Although there are no validated instruments for identifying “post-procedure neuritis,” one previous study used the Douleur Neuropathique 4 Questionnaire (DN4) and reported a 0% incidence after RFA for many conditions, including sacroiliac joint pain, regardless of post-lesion steroid administration, suggesting inadequate sensitivity compared with clinical studies that did not employ questionnaires validated for neuropathic pain.3,6 In our guidelines, we found mixed evidence for the use of post-lesion corticosteroids to prevent neuritis. We also found low-quality evidence to support the use of non-steroidal anti-inflammatory drugs, which must be weighed against an increased risk of bleeding, including into the sacral spinal canal when finder needles are placed within the dorsal aspect of the sacral foramina.