Needle Aponeurotomy of Dupuytren’s Contracture Causing 4th Digital Neuropathy
Stephen Jaworski1, Connie Tang1, Todd Garber1
1Neurology, Lehigh Valley Health Network
Objective:
NA 
Background:
Dupuytren’s contracture has previously been reported to cause a 4th digital neuropathy, but there are no previously reported cases of 4th digital neuropathy caused by surgical correction of Dupuytren’s contracture. In this report, we describe a case of needle aponeurotomy leading to development of a digital neuropathy, and we detail a novel method for identifying a 4th digital neuropathy. 
Design/Methods:
A 70-year-old woman presented with a 5-month history of persistent numbness and discomfort affecting the median nerve territory of the 4th digit of her right hand which had started immediately following needle aponeurotomy for Dupuytren’s contracture of the right 3rd digit. Electromyography and nerve conduction studies were performed. Comparison study of the ulnar and median innervation of the right 4th digit did not show differences in latencies. The same comparison study of the ulnar and median nerve was performed on the left hand and yielded normal results. Comparison of the amplitude of the right and left ulnar nerve responses from these studies showed similar results (25.0 µV on the right and 23.1 µV on the left), while median nerve responses showed much lower amplitude of the right median nerve (4.6 µV) compared to the left median nerve (30.5 µV). 
Results:

Comparison studies of the innervation of the 4th digit are often used to provide evidence of a median neuropathy at the carpal tunnel by demonstrating different latencies from the same stimulus site. The amplitudes that are measured during these studies are usually disregarded; however, they appear to have usefulness for demonstrating the presence of a digital neuropathy.

Conclusions:
This case describes 4th digital neuropathy as a consequence of needle aponeurotomy for Dupuytren’s contracture and details a methodology to generate electrographic support for a presumed digital neuropathy by comparing analogous nerve studies from contralateral limbs.
10.1212/WNL.0000000000208895
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