Surgical treatment of spontaneous posterior interosseous nerve palsy with hourglass-like constriction

Spontaneous Radial Nerve Palsy due to an Unrecognized Myofibroma: A Case Report

CASE

A 33-year-old woman presented with a six-month history of spontaneous radial nerve palsy and no identified lesion on imaging. She underwent operative exploration where an hourglass deformity was seen and resected. Pathology returned as a rare tumor, a myofibroma. The patient regained full radial nerve function.

CONCLUSIONS

A trial of observation is often indicated in the cases of isolated nerve palsy where anatomic lesions have been eliminated. This case highlights that imaging studies can miss a tumor involving nerve and that painless, spontaneous nerve palsy may be a time where early surgical intervention offers a better chance of recovery.

Isolated spontaneous posterior interosseous nerve palsy: a review of aetiology and management

Isolated posterior interosseous nerve palsy is an uncommon condition and its management is controversial. Existing literature is sparse and a treatment algorithm based on existing best evidence is absent. A comprehensive review was undertaken to elucidate the causes of spontaneous posterior interosseous nerve palsy and suggest a management strategy based on the current evidence. Posterior interosseous nerve palsy can be broadly categorized as compressive and non-compressive, and the existing evidence supports surgical intervention for compressive palsy. For posterior interosseous nerve pathology with no compressive lesion on imaging, conservative management should be tried first. Surgery is therefore reserved for compressive lesions and for failure of conservative management. The commonly performed operative procedures include decompression and neurolysis, neurorrhaphy and nerve grafting, and tendon transfers with or without nerve grafting performed as a salvage procedure. The prognosis is poorer in patients aged > 50 years, those with a delay to surgery, and those who have had long-standing compression with severe fascicular thinning.

Posterior interosseous nerve entrapments: review of the literature. Is the entrapment distal to the arcade of Frohse a really rare condition?

INTRODUCTION

Spontaneous posterior interosseous nerve palsy is a rare condition. Entrapment is mostly at level of the arcade of Frohse, and a few cases of distal entrapment have been described.

METHODS

A case of entrapment distal to the arcade of Frohse is described here. Cases of distal entrapment have been reviewed from the published literature in order to evaluate the frequency of atraumatic mechanical palsy.

RESULTS

Seven cases of distal entrapment have been identified. Lesion is the cause of palsy in 58.7% of the cases and entrapment in 20.65%. The pathology is at the elbow in 33.7% of the cases, at the arcade of Frohse in 28.26%, and at the supinator canal in 10.33%. Entrapment is at the arcade of Frohse in 64.45%, proximal in 20%, and distal in 15.55%.

CONCLUSION

Posterior interosseous nerve distal entrapment is a rare condition; therefore, further investigation is needed when radiological images at the arcade of Frohse do not show any entrapment.

Management of Atraumatic Posterior Interosseous Nerve Palsy

The posterior interosseous nerve (PIN) is susceptible to a number of traumatic and atraumatic pathologies. In this article, we aim to review our current understanding of the etiology, pathology, diagnosis, treatment options, and published outcomes of atraumatic PIN palsy. In general, the etiology of atraumatic PIN palsy can be divided into mechanical, which is caused by an extrinsic compressive force on the nerve, and nonmechanical, which is caused by an intrinsic inflammatory reaction within the nerve. As per this discussion, there are 3 causes for atraumatic PIN palsy. These are entrapment neuropathy, Parsonage-Turner syndrome, and spontaneous "hourglass" constriction. The typical presentation of atraumatic PIN palsy is a patient with spontaneous onset of weakness of fingers/thumb metacarpophalangeal joints extension. However, the wrist extension is preserved with radial deviation due to preservation of extensor carpi radialis longus/brevis function. Magnetic resonance imaging is the imaging of choice and neurophysiology is indicated in all patients. If there is an obvious structural cause of the nerve palsy, prompt decompression and removal of the causative lesion are recommended to avoid irreversible damage to the nerve/muscles. Otherwise, in general, we would recommend consideration for exploration should there be no sign of recovery after 6 weeks of observation.