Interfascicular Anatomy of the Motor Branch of the Ulnar Nerve: A Cadaveric Study.

PURPOSE: The motor branch of the ulnar nerve contains fascicles that innervate the intrinsic musculature of the hand. This cadaveric study aimed to describe the organization and consistency of the internal topography of the motor branch of the ulnar nerve. METHODS: Five fresh-frozen cadaveric specimens with an average age of 74 years (range, 65-88 years) were dissected. The ulnar nerve was exposed and transfixed to the underlying tissues to maintain its orientation throughout the dissection. The dorsal cutaneous branch (DCB) and the volar sensory branch were identified and reflected to expose the motor branch. The fascicles to the first dorsal interosseus (FDI), flexor pollicis brevis, and abductor digiti minimi (ADM) were identified. Internal neurolysis was performed distal to proximal to identify the interfascicular arrangement of these fascicles within the motor branch. The organization of these fascicles was noted, and the branch points of the DCB, FDI, and ADM were measured relative to the pisiform using a handheld electronic caliper. RESULTS: The internal topography of the motor branch was consistent among all specimens. Proximal to the pisiform, the arrangement from radial to ulnar was as follows: volar sensory branch, flexor pollicis brevis, FDI/intrinsic muscles, ADM, and DCB. The position of these branches remained consistent as the deep motor branch curved radially within the palm and traveled to the terminal musculature. The locations of the average branch points of the FDI, ADM, and DCB with respect to the pisiform were as follows: FDI, 4.6 cm distal (range, 4.1-4.9 cm), 4.5 cm radial (range, 4.1-4.9 cm); ADM, 0.65 cm distal (range, 0.3-1.1 cm), 0.7 cm radial (range, 0.3-1.1 cm), DCB, 7.7 cm proximal (range, 4.2-10.1 cm), and 0.4 cm ulnar (range, 0.3-0.8 cm). CONCLUSIONS: The internal topography of the ulnar nerve motor branch was consistent among the specimens studied. The topography of the motor branches was maintained as the motor branch turns radially within the palm. CLINICAL RELEVANCE: This study provides further understanding of the internal topography of the ulnar nerve motor branch at the wrist level.

Secondary Procedures following Flexor Tendon Reconstruction.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the indications and management options for secondary flexor tendon reconstruction, including tenolysis, tendon grafting, and tendon transfers. 2. Understand the reconstructive options for pulley reconstruction. 3. Understand the options for management of isolated flexor digitorum profundus injuries. SUMMARY: Despite current advances in flexor tendon repair, complications can still occur following surgery. This article presents the spectrum of treatment options for secondary flexor tendon reconstruction ranging from tenolysis to one- and two-stage tendon grafting, and tendon transfers. In addition, an overview of pulley reconstruction and the treatment of isolated flexor digitorum profundus injuries are discussed. A management algorithm for secondary flexor tendon reconstruction is provided.

Function-Blocking RHAMM Peptides Attenuate Fibrosis and Promote Antifibrotic Adipokines in a Bleomycin-Induced Murine Model of Systemic Sclerosis.

Systemic sclerosis a chronic, fibrotic disorder associated with high disease-specific mortality and morbidity. Cutaneous manifestations include dermal thickening and obliteration of dermal adipose tissue. Accumulation of low-molecular-weight hyaluronan, which signals through the receptor for hyaluronan-mediated motility, RHAMM, leads to progressive fibrosis and is correlated with increased severity of systemic sclerosis. The purpose of this study is to test the efficacy of two function-blocking RHAMM peptides, NPI-110 and NPI-106, in reducing skin fibrosis in a bleomycin-induced mouse model of systemic sclerosis. NPI-110 reduced visible measures of fibrosis (dermal thickness and collagen production, deposition, and organization) and profibrotic gene expression (Tgfb1, c-Myc, Col1a1, Col3a1). NPI-110 treatment also increased the expression of the antifibrotic adipokines perilipin and adiponectin. Both RHAMM peptides strongly reduced dermal RHAMM expression, predicting that dermal fibroblasts are peptide targets. Transcriptome and cell culture analyses using Rhamm-/- and Rhamm-rescued dermal fibroblasts reveal a TGFß1/RHAMM/MYC signaling axis that promotes fibrogenic gene expression and myofibroblast differentiation. RHAMM function‒blocking peptides suppress this signaling and prevent TGFß1-induced myofibroblast differentiation. These results suggest that inhibiting RHAMM signaling will offer a treatment method for cutaneous fibrosis in systemic sclerosis.