J Korean Neurosurg Soc.  2014 Mar;55(3):148-151. 10.3340/jkns.2014.55.3.148.

Clinical Features of Wrist Drop Caused by Compressive Radial Neuropathy and Its Anatomical Considerations

• Han BR
• Cho YJ
• Yang JS
• Kang SH
• Choi HJ

• KMID: 2191080
• DOI: http://doi.org/10.3340/jkns.2014.55.3.148

Abstract

OBJECTIVE
Posture-induced radial neuropathy, known as Saturday night palsy, occurs because of compression of the radial nerve. The clinical symptoms of radial neuropathy are similar to stroke or a herniated cervical disk, which makes it difficult to diagnose and sometimes leads to inappropriate evaluations. The purpose of our study was to establish the clinical characteristics and diagnostic assessment of compressive radial neuropathy.
METHODS
Retrospectively, we reviewed neurophysiologic studies on 25 patients diagnosed with radial nerve palsy, who experienced wrist drop after maintaining a certain posture for an extended period. The neurologic presentations, clinical prognosis, and electrophysiology of the patients were obtained from medical records.
RESULTS
Subjects were 19 males and 6 females. The median age at diagnosis was 46 years. The right arm was affected in 13 patients and the left arm in 12 patients. The condition was induced by sleeping with the arms hanging over the armrest of a chair because of drunkenness, sleeping while bending the arm under the pillow, during drinking, and unknown. The most common clinical presentation was a wrist drop and paresthesia on the dorsum of the 1st to 3rd fingers. Improvement began after a mean of 2.4 weeks. Electrophysiologic evaluation was performed after 2 weeks that revealed delayed nerve conduction velocity in all patients.
CONCLUSION
Wrist drop is an entrapment syndrome that has a good prognosis within several weeks. Awareness of its clinical characteristics and diagnostic assessment methods may help clinicians make diagnosis of radial neuropathy and exclude irrelevant evaluations.

Keyword

Radial nerve; Entrapment syndrome; Posterior interosseous nerve; Superficial radial nerve; Arcade of Frohse

MeSH Terms

Arm
Diagnosis
Drinking
Electrophysiology
Female
Fingers
Humans
Male
Medical Records
Neural Conduction
Paralysis
Parasomnias
Paresthesia
Posture
Prognosis
Radial Nerve
Radial Neuropathy*
Retrospective Studies
Stroke
Wrist*

Figure

• 

  Fig. 1 Clinical characteristics of patients with compressive radial neuropathy and its prognosis. A : Radial neuropathy was caused by sleeping after getting drunk in 68% of patients, and in another 20% of patients it was associated with sleep posture such as bending the arm under the pillow. Overall, 88% of cases were related to sleep postures. B : Most (88%) of the patients were exposed to compression for 2-4 h, and the average time to develop neuropathy was 178.8 minutes. C : Subjective clinical improvements (decreased paresthesia, recovery of wrist or finger extensor) began after a mean of 2.4 weeks. Most (82%) of the patients felt sensory improvement within 2 weeks.

• 

  Fig. 2 Schematic illustration of the distribution and functions of the radial nerve and its branches. At the level of the "arcade of Frohse," the radial nerve bifurcates into the posterior interosseous nerve (PIN) and the superficial radial nerve (SRN). A radial nerve injury above the elbow may present with weakness of elbow extension and wrist extension with decreased sensation in the distributions of both the PIN and SRN. This bifurcated location is important in localizing the origins of the pathologic lesion during diagnostic examinations.

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