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Abstract Details

Carpal and Cubital Tunnel Surgical Release in HNPP and CMT1A: Success Predictors and Outcomes
Neuromuscular and Clinical Neurophysiology (EMG)
P9 - Poster Session 9 (5:30 PM-6:30 PM)
11-004
Carpal (CTS) and cubital (CuTS) tunnel syndrome frequently occur in HNPP and CMT1A patients, but data on value of surgical nerve decompressions are limited.

To evaluate outcomes of carpal and cubital tunnel release in patients with hereditary neuropathy with pressure palsies (HNPP) and Charcot-Marie-Tooth-1A (CMT1A).

HNPP and CMT1A genetically diagnosed between 2017 and 2020 with electrophysiologic, ultrasonographic evaluations and longitudinal follow up for CTS and CuTS surgical decompression were reviewed.

Clinical CTS occurred in 57.9%(11/19) of HNPP and 14.3%(6/42) of CMT1A while CuTS occurred in 42.1%(8/19) of HNPP and 7.1%(3/42) of CMT1A. Twelve CTS (7 HNPP and 5 CMT1A) and 5 CuTS (1 CMT1A and 4 HNPP) underwent surgical decompression with an average follow up 62 months (4-180 months). Preoperatively, median and ulnar sensory amplitudes were absent in all CMT1A but variably reduced in HNPP (median=16±8.2 μV, ulnar=15.3±5.3 μV). In HNPP, median and ulnar nerve ultrasound showed focal enlargements at the carpal tunnel [mean cross-sectional area (CSA)=14.3±3.5 mm2 at wrist, 6±1 mm2 at forearm] and the cubital tunnel (CSA=17±7 mm2). In CMT1A, diffuse median nerve enlargements occurred (mean CSA=16 mm2 at wrist, 22.5±0.5 mm2 at forearm) without focal enlargements at the carpal or cubital tunnel. Sustained postsurgical improvements at last visit determined by pain reduction and improved hand function (sensation, strength) occurred in 80% of CMT1A and 43% of HNPP. In HNPP, CTS symptom improvement was seen only in patients with activity-provoking symptoms. Only the CMT1A case improved with CuTS surgery while 50%(2/4) of HNPP patients immediately worsened clinically and electrophysiologically.

CMT1A patients are more likely than HNPP patients to see benefits from upper extremity nerve decompression. Nerve conduction abnormalities and sonographic nerve enlargements aid the diagnosis but do not inform on surgical outcomes. Recognizing activity induced symptoms in HNPP patients best informs who will benefit from decompressive surgery.

Authors/Disclosures
Pitcha Chompoopong, MD (University of Minnesota)
PRESENTER
Dr. Chompoopong has nothing to disclose.
Zhiyv Niu, PhD, FACMG (Mayo Clinic) Zhiyv Niu has nothing to disclose.
Kamal Shouman, MD (Mayo Clinic) The institution of Dr. Shouman has received research support from dysautonomia international.
Nicolas N. Madigan, MD Dr. Madigan has nothing to disclose.
Paola Sandroni, MD, PhD, FAAN (Mayo Clinic) Dr. Sandroni has nothing to disclose.
Sarah E. Berini, MD (Mayo Clinic) Dr. Berini has nothing to disclose.
Alexander Y. Shin, MD (Mayo Clinic) The institution of Dr. Shin has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for TriMed Orthopedics/Mayo Medical Ventures. Dr. Shin has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Aptis Medical. Dr. Shin has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Techniques in Hand and Upper Extremity Surgery. Dr. Shin has received publishing royalties from a publication relating to health care.
Jeffrey Brault No disclosure on file
Andrea Boon, MD (Mayo Clinic) Dr. Boon has received personal compensation in the range of $500-$4,999 for serving as a Consultant for HPE cosmetics .
Ruple S. Laughlin, MD, FAAN (Mayo Clinic Rochester) Dr. Laughlin has nothing to disclose.
Thorland Erik The institution of Thorland Erik has received research support from NIH. The institution of Thorland Erik has received research support from NIH.
Jayawant Narayan Mandrekar, PhD Dr. Mandrekar has nothing to disclose.
Christopher J. Klein, MD, FAAN (Mayo Clinic) Dr. Klein has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Takeda. Dr. Klein has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sangamo Therapeutics . Dr. Klein has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Faze Medicine .