Superior Cluneal Neuralgia from Iliocostal Impingement Treated with Phenol Neurolysis: A Case Report

Background: Superior cluneal neuralgia (SCN) is an increasingly recognized yet still frequently overlooked cause of chronic lumbosacral and buttock pain. While historically attributed generally to iatrogenic iliac crest injury (bone marrow biopsy or bone graft harvest), more recently it is recognized as occurring in the absence of any trauma, with idiopathic entrapment resulting in compression neuropathy. Iliocostal impingement syndrome (IIS) is an even less commonly considered condition whereby the lower costal margin repetitively contacts and irritates the iliac crest, primarily occurring unilaterally and owing to severe scoliosis, but also in the context of severe vertebral column height loss. Case Report: We report here a case of an elderly woman with a 3-inch reported height loss over the decades who had suffered with chronic and intractable right lumbosacral and gluteal pain, and whom, on the basis of physical examination, we diagnosed presumptively with both SCN and with IIS as the underlying pathophysiologic mechanism. After undergoing successful diagnostic fluoroscopically guided superior cluneal nerve block, she was offered phenol denervation and enjoyed 9 months of reported 90% improvement in her symptoms, with gradual return to baseline over the next couple months. She has subsequently undergone repeat phenol denervation twice, with similarly good results. We believe this to be the first documented application of phenol neurolytic technique to SCN, and in the case of iliocostal impingement we argue that surgical release/resection or even peripheral nerve stimulation may not be effective owing to underlying compression/irritation diathesis from the inevitable pressure of the costal margin upon the iliac crest. Conclusion: In this case report, we also briefly summarize the current literature on SCN and compare phenol neurolysis to other therapeutic modalities. Key words: Superior cluneal nerves, neuralgia, iliocostal impingement, phenol, denervation