Department of Neurosurgery, University of Wisconsin, Madison, WI, USA
17.1 Case Presentation
A 74-year-old male, with a 20-year-history of progressive sensorimotor polyneuropathy, has recent increase in weakness of the left hand with loss of dexterity as well as numbness of the medial one and a half fingers. He is taking gabapentin, which is controlling his pain very well. PMH: hypertension, migraine, kidney stones, peptic ulcer, and left hip replacement. He used to smoke cigarettes but quit 35 years ago; he takes 15 alcoholic drinks per week. His father died of metastatic cancer. Examination of the left hand reveals significant atrophy of the FDI , IO 3, FDP to 4th and 5th digits 4. The remaining muscle groups are 4+/5. Sensation to light touch and pinprick is diminished over the little finger and medial half of the ring finger on the left, extending to the medial aspect of the hand up to the wrist both palmar and dorsal aspects. DTRs are 1+ in the upper limbs and 0 in the lower limbs. Romberg’s test is positive.
What is the most likely diagnosis?
What studies do you need?
How would you treat this disease?
Are there other options? Why did you choose this treatment?
Describe the treatment you chose.
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This is likely a left ulnar neuropathy at the elbow. The sensory loss (hatch marks in Fig. 17.1A, B ) fits with the elbow location since it involves the dorsal aspect of the hand (the dorsal cutaneous branch of the ulnar n takes off above the wrist), and sparing of the forearm sensation (MABC ). The motor deficits also fit with the elbow since the FDP is involved. Figure 17.1A shows left FDI atrophy and Wartenberg’s sign. (B) shows hypothenar atrophy. Look for a Tinel’s sign, and test for subluxation.
Tinel’s sign was positive over the ulnar n at the left elbow. There was no subluxation.
EMG / NCS confirmed left ulnar neuropathy at the elbow (Appendix 6) in addition to distal sensorimotor polyneuropathy.
In the setting of significant amount of weakness and atrophy, left ulnar n decompression at the elbow should be recommended. Realistic expectations should be set forth, because of the underlying polyneuropathy and the presence of significant atrophy.
Other options include ulnar n transposition . Multiple randomized trials did not show any superiority of transposition over simple decompression; however, there were more complications with transposition . Transposition offers at least a theoretical benefit of decreased strain on the ulnar n in full elbow flexion . Transposition is still an option in this case; however, in the absence of significant subluxation or deformity, most surgeons prefer simple decompression.
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