Introduction Severe proximal median nerve palsies often result in irreversible thenar atrophy and thumb abduction function loss. Tendon transfer involves substantial limitations and challenges; but, distal nerve transfer may provide an alternative treatment. Our goal was to validate the anatomical suitability of two distal ulnar nerve branches for thenar muscle reanimation. Materials and Methods We assessed nerve transfer to the recurrent branch of median nerve (RMN) in 16 embalmed cadaveric hands. The ulnar motor branch to the flexor digiti minimi brevis (FDMBn) and the ulnar motor branch to the third lumbrical (3rdLn) were assessed for transfer. Coaptation success was measured by the overlap of the nerve donor with the RMN and correspondence of nerve diameters. Results The mean transferable length and width of the RMN were 20.7 ± 4.5 and 1.0 ± 0.3 mm, respectively. We identified an average of three branches in the branching anatomy from the ulnar nerve to the hypothenar muscles. The maximal transferable lengths and widths of the FDMBn and the 3rdLn were 13.8 ± 4.4 and 0.5 ± 0.1 mm and 24.1 ± 6.4 and 0.4 ± 0.1 mm, respectively. The overlap with the RMN of the FDMBn and 3rdLn was 9.0 ± 3.6 (2.0–15.3) and 17.8 ± 6.0 (4.7–27.5) mm, respectively. Conclusions This anatomical study demonstrates the feasibility of distal nerve transfers between the ulnar and median nerves in the hand for reanimation of thenar muscles. Ulnar motor donors of the BrFDMBn and 3rdLn likely represent the least morbid donors with short distances for regeneration and a single coaptation repair.

The recurrent branch of the median nerve innervates the thenar muscles. Therefore, injury to the median nerve as it courses from the axilla to the hand has profound negative effects on the functional use of the thumb. The surgical procedure of peripheral nerve transplants in order to regain function in denervated muscle is well documented. Using the lumbrical branch of the ulnar nerve to the 4th digit as a nerve transplant with the recurrent branch of the median nerve in order to regain function is not well documented. As such, the capacity of grafting these ulnar nerve branches from their anatomical position including neuron count of each nerve and their ability to be spliced together was investigated. Cadaveric dissections were performed to document the distribution of the deep branch of the ulnar nerve as it enters the lumbrical musculature and the recurrent branch of the median nerve as it courses through the carpal tunnel. After the dissection was completed, the ulnar branch to the lumbrical muscle was drawn towards the recurrent branch of the median nerve. Using a digital camera, and electronic calipers the nerves were photographed for visual confirmation of the ability to transfer and measured to compare the size of the nerves. Sections of each branch were then studied for a comparison of neuron counts. Data suggests the nerve transfer to be a viable option, and could assist neurosurgeons in performing surgeries to help patients regain functionality in their thenar muscles. A continuation of data collection will allow greater insight into the number of neurons that can potentially re‐innervate the thenar muscles as well as assist in desired surgical outcomes.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cadaver dissections are an essential anatomical teaching tool in health sciences. However, these dissection courses increase staff and students to formaldehyde exposure. The Occupational Safety and Health Administration (OSHA) previously set standards designed to protect individuals from excess formaldehyde and individuals working in the laboratories were protected through ventilation. However, older buildings that host cadaveric dissections may not provide the ventilation necessary to adequately keep formaldehyde levels below a safe threshold. Constructing or renovating a building's ventilation system is expensive. The estimated cost to retrofit the ventilation system in the University of Utah's anatomy lab was three million dollars. This study sought to determine a cost‐effective solution to reduce formaldehyde exposure; thereby creating a safe environment for laboratory occupants. Using formaldehyde‐monitoring badges strategically placed above each cadaver and on each dissector, dissections were conducted for 200‐230‐minute intervals. The badges were analyzed and showed formaldehyde Permissible Exposure Levels (PELs) were above OSHA limits (0.34‐1.91ppm). Dissection gurneys were then fitted with paired side vents measuring 64 x 4 x 4 inches. These vents were attached to the Python Portable Floor Sentry‐Fume Extractor (Model #SS‐450‐PYT; Sentry Air Systems) measuring 19.5 x 22.5 x 20 inches, which directed air surrounding the embalmed body through the formaldehyde filtration system. Following the installation of down‐draft tables, and using the same experimental method, data from eight new badges were analyzed. These samples resulted in PEL levels between 0.06‐0.13 ppm, well below the OSHA limit. With the use of down‐draft tables, formaldehyde PEL levels were reduced by an average of 0.63ppm; a statistically significant decrease (T‐test of 0.036). The cost to retrofit 10 gurneys into down‐draft tables was approximately 55,000 dollars, saving the University more than 2.9 million. This study suggests the use of modified down‐draft tables provide an affordable and safe environment for anatomy dissection personnel, as well as a cost‐ and time‐effective alternative to retrofitting ventilation in facilities not specifically designed for dissection.