Outcomes after Anterior Interosseous Nerve to Ulnar Motor Nerve Transfer.

Background Ulnar nerve lesions proximal to the elbow can result in loss of intrinsic muscle function of the hand. The anterior interosseous nerve (AIN) to deep motor branch of the ulnar nerve (DBUN) transfer has been demonstrated to provide intrinsic muscle reinnervation, thereby preventing clawing and improving pinch and grip strength. The purpose of this study was to evaluate the efficacy of the AIN to DBUN transfer in restoring intrinsic muscle function for patients with traumatic ulnar nerve lesions. Methods We performed a prospective, multi-institutional study of outcomes following AIN to DBUN transfer for high ulnar nerve injuries. Twelve patients were identified, nine of which were enrolled in the study. The mean time from injury to surgery was 15 weeks. Results At final follow-up (mean postoperative follow-up 18 months + 15.5), clawing was observed in all nine patients with metacarpophalangeal joint hyperextension of the ring finger averaging 8.9 degrees (+ 10.8) and small finger averaging 14.6 degrees (+ 12.5). Grip strength of the affected hand was 27% of the unaffected extremity. Pinch strength of the affected hand was 29% of the unaffected extremity. None of our patients experienced claw prevention after either end-to-end ( n = 4) or end-to-side ( n = 5) AIN to DBUN transfer. Conclusion We conclude that, in traumatic high ulnar nerve injuries, the AIN to DBUN transfer does not provide adequate intrinsic muscle reinnervation to prevent clawing and normalize grip and pinch strength.

The Notch pathway regulates the bone gain induced by PTH anabolic signaling.

Parathyroid hormone (PTH) signaling downstream of the PTH 1 receptor (Pth1r) results in both bone anabolic and catabolic actions by mechanisms not yet fully understood. In this study, we show that Pth1r signaling upregulates the expression of several components of the Notch pathway and that Notch signals contribute to the catabolic actions of PTH in bone. We found that constitutive genetic activation of PTH receptor signaling in osteocytes (caPth1rOt ) or treatment with PTH daily increased the expression of several Notch ligands/receptors in bone. In contrast, sustained elevation of endogenous PTH did not change Notch components expression. Deletion of the PTH receptor or sclerostin overexpression in osteocytes abolished Notch increases by PTH. Further, deleting the canonical Notch transcription factor Rbpjk in osteocytes decreased bone mass and increased resorption and Rankl expression in caPth1rOt mice. Moreover, pharmacological bone-targeted Notch inhibition potentiated the bone mass gain induced by intermittent PTH by reducing bone resorption and preserving bone formation. Thus, Notch activation lies downstream of anabolic signaling driven by PTH actions in osteocytes, and Notch pharmacological inhibition maximizes the bone anabolic effects of PTH.

Side-to-Side Metacarpal Fusion for Reconstruction of Bone Loss in the Radial Carpometacarpal Joints.

We present a unique case of side-to-side metacarpal fusion for reconstruction after an isolated gunshot wound to the right hand of a 19-year-old woman. There was a traumatic segmental loss of the proximal right second metacarpal base with considerable comminution of the trapezium and trapezoid. Reconstructive options were limited because of the destruction of the distal carpus and carpometacarpal (CMC) joint. Digital ray amputation was offered but deferred because of patient preference. The reconstruction was performed via metacarpal fusion of the second metacarpal remnant to the third metacarpal base, bypassing the previously destroyed second CMC joint. The fusion of the second and third metacarpals offers acceptable results when the radial CMC joints are traumatized with extensive bone loss.

Unique Complications of Venous Anastomotic Couplers: A Systematic Review of the Literature.

BACKGROUND: Anastomotic couplers expedite venous microvascular anastomoses and have been established as an equivalent alternative to hand-sewn anastomoses. However, complications unique to the coupler such as palpability and extrusion can occur. The purpose of this study was to perform a systematic review of the literature to assess complications distinct to the venous anastomotic coupler. METHODS: A Medline, PubMed, EBSCO host search of articles involving anastomotic venous couplers was performed. Studies involving arterial anastomotic couplers, end-to-side anastomoses, and reviews were excluded. Data points of interest were flap failure, venous thrombosis, hematoma, partial flap necrosis, infection, coupler extrusion, and coupler palpability. RESULTS: The search identified 165 articles; 41 of these met inclusion criteria. A total of 8,246 patients underwent 8,955 venous-coupled anastomoses. Combined reoperation rate was 3.3% and all-cause unsalvageable flap failure was 1.0%. Complications requiring reoperation included venous thrombosis (2.0%), hematoma (0.4%), partial flap necrosis (0.4%), and infection (0.3%). Eight patients had palpable couplers and 11 patients had extrusion of couplers (head/neck, hand, and feet) and required operative management. CONCLUSION: Venous couplers remain an equivalent alternative to conventional hand-sewn anastomosis. However, venous coupler extrusion and palpability in the late postoperative period is a complication unique to anastomotic couplers, particularly in radiated head and neck, feet and hand free flaps. Removing extruded venous couplers is safe after tissue integration 3 weeks postoperatively. Coupler palpability and extrusion should be integrated into preoperative patient counseling and assessed in follow-up examinations.