Posterior interosseous nerve syndrome due to intramuscular lipoma

Forearm Lipoma Causing PIN Compression: Literature Review and Meta-Analysis of Predictors for Motor Recovery

BACKGROUND

Lipomas are a rare cause of posterior interosseous nerve (PIN) compression. A systematic review of predictors for motor recovery has not been performed. This study sought to evaluate whether patient or lipoma characteristics are associated with motor recovery and could be used to determine when immediate tendon transfers at the time of excision should be performed.

METHODS

Articles describing patients with forearm lipomas resulting in PIN compression with motor weakness were included. Patient age, gender, symptom duration, laterality and largest dimension of lipoma, surgical intervention, and motor recovery were identified. Article quality was assessed via the Methodological Index for Non-Randomized Studies criteria.

RESULTS

Thirty articles reporting on 34 patients were identified. Average age was 58.2 years. Average largest lipoma dimension was 5.7 cm. All patients underwent lipoma removal, and 2 had concomitant tendon transfers. In all, 73.5% of patients had complete motor recovery at an average of 9.7 months. Patient age and largest dimension of lipoma, and duration of symptoms were not significant predictors of motor recovery. Symptom duration was a significant predictor of motor recovery in binary regression, particularly if < 18 months.

CONCLUSIONS

The majority of patients with PIN weakness secondary to lipoma are likely to have complete motor recovery after excision alone. Concomitant tendon transfers should be considered for patients symptomatic for greater than 18 months. Further, adequately powered, studies are required to stratify risk factors and evaluate other modalities to identify the minority of patients who would benefit from immediate tendon transfer.

Ulnar Nerve Compression at the Elbow Secondary to Intramuscular Lipoma of the Flexor Carpi Ulnaris: A Case Report

CASE

A 62-year-old right-hand-dominant woman presented with 1 year of persistent radiating pain, weakness, and paresthesias in her left forearm and hand. Electromyography findings were significant for ulnar neuropathy distal to the branch innervating the flexor carpi ulnaris (FCU), without superimposed cervical radiculopathy or other focal entrapment neuropathy. During open ulnar nerve neurolysis, an intramuscular lipoma was encountered within the FCU. Lipoma excision and cubital tunnel release with ulnar nerve transposition were performed with complete relief of neuropraxia.

CONCLUSION

We demonstrate full neurologic recovery after intramuscular lipoma excision and cubital tunnel release. Although rare, anomalous anatomy and tissue overgrowth should remain on the differential for patients presenting with atypical neuropraxia.

A Case Report on Parosteal Lipoma Stretching the Posterior Interosseous Nerve Without Causing Palsy

Lipomas are benign soft tissue tumors that can be either superficial or deep. Superficial lipomas are mostly asymptomatic whereas deep-seated lipomas can occasionally cause symptoms if they grow adjacent to neurovascular structures. In this report, we present a case of parosteal lipoma of the right proximal forearm in a 47-year-old male, which was initially diagnosed as intramuscular lipoma stretching posterior interosseous nerve (PIN), with no neurological complaints during both preoperative and postoperative periods.

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.

Intraneural Posterior Interosseous Nerve Lipoma with Complete Paralysis: Case Report and Review of the Literature

An intraneural posterior interosseous nerve (PIN) lipoma is a rare entity consisting of two types and only two previously reported cases. Treatment involves total excision for the well-encapsulated “true intraneural lipomas” type and subtotal resection for the other type, fibrolipomatous hamartomas of the nerve. We present the management and surgical treatment of a case that illustrates a variation of the traditional posterolateral surgical approach for the complete excision of an intraneural PIN lipoma—contrary to the more commonly used anterior approach in literature—along with a literature review of intraneural PIN lipomas.

Retrospective Analysis of 20 Patients With Schwannomas: Magnetic Resonance Imaging Characteristics, Pain, and Outcomes Following Excision

A Tinel's sign, a percussion-induced, painful sensation, has been reported as the most useful sign for diagnosing a schwannoma. On magnetic resonance imaging, schwannomas often exhibit a split fat sign and a target sign. The typical treatment for schwannomas is surgical excision; however, excision often results in high rates of neurological deficit. The authors retrospectively reviewed 20 patients who underwent excision of a schwannoma from 2007 to 2015. Twenty patients presented with a split fat sign and 12 patients presented with a Tinel's sign on magnetic resonance imaging. Only 3 patients presented with a target sign on magnetic resonance imaging. The operative approach involved removing the schwannoma, preserving the nearby nerve fascicles, and leaving the epineurium open. Follow-up ranged from 3 to 91 months (average, 29 months). At final follow-up, all patients were pain free. Nineteen patients had normal sensation and full function of their affected limb. One patient developed postoperative posterior interosseous nerve palsy. A Tinel's sign, preoperative pain, and a split fat sign on preoperative magnetic resonance imaging are the clinical symptoms most useful for diagnosing a schwannoma. Schwannomas can be safely removed via intracapsular surgical excision with minimal complications, yielding eradication of preoperative pain, normal sensation, and full function. [Orthopedics. 2017; 40(6):e1036-e1043.].