Microcirculatory response to cold stress test in the healthy hand.

OBJECTIVE: Cold sensitivity of the fingers is common in several conditions. It has been linked to digital vasospasm, microvascular dysfunction, and neural mechanisms. This study aimed to investigate the normal digital microvascular response to a cold stress test in healthy individuals using Laser Speckle Contrast Imaging (LSCI). METHODS: Twenty-six healthy individuals, mean age 31 (SD 9) years were included. Skin perfusion of digits II-V was measured using Laser Speckle Contrast Imaging before and after a standardized cold stress test. Changes in skin perfusion from baseline were analyzed between hands, digits, and sexes. RESULTS: Skin perfusion was significantly (p < 0.0001) affected by cold provocation in both the cold exposed and the contralateral hands in all participants of the study. This effect was significantly different between the radial (digit II and III) and the ulnar (digit V) side of the hands (p < 0.001). There was a trend towards a larger decrease in perfusion in men (ns), and a faster recovery to baseline values in women (ns). A larger inter subject variability was seen in perfusion values in women. CONCLUSIONS: The normal microvascular response to cold provocation may involve both centrally and regionally mediated processes. When exposing one hand to a cold stress test, the contralateral hand responds with simultaneous but smaller decreases in perfusion.

Neuroplasticity following Nerve Transfer of the Anterior Interosseous Nerve for Proximal Ulnar Nerve Injuries.

BACKGROUND: Injuries to the ulnar nerve at or above proximal forearm level result in poor recovery despite early microsurgical repair, especially concerning the intrinsic motor function of the hand. To augment the numbers of regenerating axons into the targeted muscles, a nerve transfer of the distal branch of the median nerve, the anterior interosseous nerve, to the ulnar motor branch has been described. METHODS: Two patients with severe atrophy of the intrinsic hand muscles following an initial proximal ulnar nerve repair had surgery with an end-to-side transfer of the anterior interosseous nerve to the ulnar motor branch at the wrist level. Outcome and neuroplasticity were prospectively studied using questionnaires, clinical examinations, electroneurography, electromyography, somatosensory evoked potentials at pre nerve transfer and 3-, 12-, and 24-months post nerve transfer as well as navigated transcranial magnetic stimulation at pre nerve transfer and 3- and 12-months post nerve transfer. RESULTS: Successively improved motor function was observed. Complete reinnervation of intrinsic hand muscles was demonstrated at 12- to 24-months follow-up by electroneurography and electromyography. At the cortical level, navigated transcranial magnetic stimulation detected a movement of the hot-spot for the abductor digiti mini muscle, originally innervated by the ulnar nerve and the size of the area from where responses could be elicited in this muscle changed over time, indicating central plastic processes. An almost complete reinnervation of the pronator quadratus muscle was also observed. CONCLUSION: Both central and peripheral plastic mechanisms are involved in muscle reinnervation after anterior interosseous nerve transfer for treatment of proximal ulnar nerve injuries.

Tensioning of the radioscaphocapitate and long radio-lunate ligaments for dynamic radiocarpal instability.

During 1994-2003, we treated 20 patients with post-traumatic radial-sided wrist pain and dynamic radiocarpal instability. After arthroscopy confirmed no disruption of the radioscaphocapitate ligament and an increased laxity of the ligament, we passed a strip of the radioscaphocapitate ligament through the long radio-lunate ligament. The rationale of this procedure was to increase tension of the two ligaments and to close the space of Poirier. Eighteen patients were assessed after 1-3.7 years (mean 2.5 years). Four patients were symptom-free and 11 patients were markedly improved. Fourteen patients were followed for 11-15 years; four patients were symptom-free and eight patients were markedly improved. Two reported unchanged symptoms and none was worse in the follow-up. Based on our findings, we suggest a cause of post-traumatic radial-sided wrist pain is laxity of the radiocarpal joint. We conclude that our surgical procedure increases tension in the radioscaphocapitate and long radio-lunate ligaments and decreases wrist pain at rest and during activity. LEVEL OF EVIDENCE: IV.

Flexor tendon repair after rupture caused by volar plate fixation of the distal radius.

Volar plate fixation of unstable fractures of the distal radius is preferred by a majority of surgeons today. One known complication is the rupture of flexor tendons. The aim of this paper is to present flexor tendon ruptures after volar plate fixation analysing the clinical outcome after tendon surgery, aetiology, and methods of prevention. Seventeen consecutive ruptures in 14 patients were included. The incidence was 1.4%. Three patients declined tendon surgery. Eleven patients were treated with a free tendon graft. Only two patients showed excellent results regarding mobility in the thumb and/or fingers. Analysis of radiographs demonstrated sub-optimal placement of plate or screws in all cases. Rupture of a flexor tendon is a serious complication where the functional outcome after surgical reconstruction is uncertain. Early removal of the plate when the placement is sub-optimal or when local volar tenderness appears would probably prevent many ruptures.