SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Forearm

169

To evaluate T2-signal of high-resolution MRI in distal ulnar nerve branches at the wrist as diagnostic sign of guyon’s-canal-syndrome (GCS).

Concepts: Forearm, Ulnar nerve, Carpal tunnel, Ulnar artery, Ulnar nerve entrapment, Ulnar canal, Guyon's canal syndrome

168

BACKGROUND: Variations in the major arteries of the upper limb are estimated to be present in up to one fifth of people, and may have significant clinical implications. CASE PRESENTATION: During routine cadaveric dissection of a 69-year-old fresh female cadaver, a superficial brachioulnar artery with an aberrant path was found bilaterally. The superficial brachioulnar artery originated at midarm level from the brachial artery, pierced the brachial fascia immediately proximal to the elbow, crossed superficial to the muscles that originated from the medial epicondyle, and ran over the pronator teres muscle in a doubling of the antebrachial fascia. It then dipped into the forearm fascia, in the gap between the flexor carpi radialis and the palmaris longus. Subsequently, it ran deep to the palmaris longus muscle belly, and superficially to the flexor digitorum superficialis muscle, reaching the gap between the latter and the flexor carpi ulnaris muscle, where it assumed is usual position lateral to the ulnar nerve. CONCLUSION: As far as the authors could determine, this variant of the superficial brachioulnar artery has only been described twice before in the literature. The existence of such a variant is of particular clinical significance, as these arteries are more susceptible to trauma, and can be easily confused with superficial veins during medical and surgical procedures, potentially leading to iatrogenic distal limb ischemia.

Concepts: Blood pressure, Muscle, Ulna, Forearm, Median nerve, Brachial artery, Muscles of the upper limb, Ulnar artery

103

Radial artery access is commonly performed for coronary angiography and invasive hemodynamic monitoring. Despite limitations in diagnostic accuracy, the modified Allen test (manual occlusion of radial and ulnar arteries followed by release of the latter and assessment of palmar blush) is used routinely to evaluate the collateral circulation to the hand and, therefore, to determine patient eligibility for radial artery access. We sought to evaluate whether a smartphone application may provide a superior alternative to the modified Allen test.

Concepts: Atherosclerosis, Heart, Atheroma, Cardiovascular system, Forearm, Brachial artery, Radial artery, Ulnar artery

54

Cross education (CE) occurs after unilateral training whereby performance of the untrained contralateral limb is enhanced. A few studies have shown that CE can preserve or “spare” strength and size of an opposite immobilized limb, but the specificity (i.e., trained homologous muscle and contraction type) of these effects is unknown. The purpose was to investigate specificity of CE “sparing” effects with immobilization. The nondominant forearm of 16 participants was immobilized with a cast, and participants were randomly assigned to a resistance training (eccentric wrist flexion, 3 times/week) or control group for 4 weeks. Pre- and posttesting involved wrist flexors and extensors eccentric, concentric and isometric maximal voluntary contractions (via dynamometer), muscle thickness (via ultrasound), and forearm muscle cross-sectional area (MCSA; via peripheral quantitative computed tomography). Only the training group showed strength preservation across all contractions in the wrist flexors of the immobilized limb (training: -2.4% vs. control: -21.6%; P = 0.04), and increased wrist flexors strength of the nonimmobilized limb (training: 30.8% vs. control: -7.4%; P = 0.04). Immobilized arm MCSA was preserved for the training group only (training: 1.3% vs. control: -2.3%; P = 0.01). Muscle thickness differed between groups for the immobilized (training: 2.8% vs. control: -3.2%; P = 0.01) and nonimmobilized wrist flexors (training: 7.1% vs. control: -3.7%; P = 0.02). Strength preservation was nonspecific to contraction type ( P = 0.69, [Formula: see text] = 0.03) yet specific to the trained flexors muscle. These findings suggest that eccentric training of the nonimmobilized limb can preserve size of the immobilized contralateral homologous muscle and strength across multiple contraction types. NEW & NOTEWORTHY Unilateral strength training preserves strength, muscle thickness, and muscle cross-sectional area in an opposite immobilized limb. The preservation of size and strength was confined to the trained homologous muscle group. However, strength was preserved across multiple contraction types.

Concepts: Muscle, Muscle contraction, Strength training, Forearm, Upper limb, Wrist, Isometric exercise, Preservation

28

This case report describes a 41-year-old female who presented with complaints of pain in the lower lateral one-third of the right radius extending into the first web space. Tinel’s sign reproducing the patient’s symptoms was elicited 8.2 cm above the radial styloid process. Physical diagnosis for superficial radial nerve entrapment was made based on a positive upper limb neural tension test 2a along with symptom reproduction during resisted isometrics to brachioradialis and wrist extensors. A potential first time successful conservative Kinesio tape (KT) management for entrapment of the superficial radial nerve is described in this report. An immediate improvement in grip strength and functional activities along with a reduction in pain and swelling was noted in this patient after the first treatment session, which was maintained at a 6 month follow-up. A model is proposed describing the mechanism by which KT application could be used to intervene for nerve entrapment interfaces.

Concepts: Upper limb anatomy, Forearm, Upper limb, Distal radius fracture, Brachioradialis, Radial nerve, Chauffeur's fracture, Radial collateral ligament

28

Complete circumferential degloving injury of the digits usually results in a large cutaneous defect with tendinous structure and bone and joint exposure. When revascularization is not possible, a thin and adequately sized flap is required to resurface the defect, restore finger function, and prevent amputation. In this report, we present our experience with reconstruction of the entire circumferential degloving injury of the digits using free fasciocutaneous flaps. Between February 2006 and January 2011, 9 male patients with circumferential degloving injury of 9 digits underwent reconstruction using free fasciocutaneous flap transfer with the posterior interosseous artery flap, medial sural artery flap, anteromedial thigh flap, or radial forearm flap. The average flap size was 14.2 × 6.9 cm. Donor sites were closed primarily or covered with split-thickness skin graft. All flaps survived completely and the donor sites healed without complications. The mean follow-up period was 34.8 months. A maximum Kapandji score (10/10) was seen in 2 cases with crushed thumbs. All patients could achieve good key pinch and grasping functions. All skin flaps showed acceptable static 2-point discrimination and adequate protective sensation. Patient satisfaction for resurfaced digits averaged 9 on a 10-points visual analogic scale. In conclusion, the free fasciocutaneous flaps used were thin and did not interfere with finger movements. The patient’s finger formed a smooth contour and acceptable functional results were obtained after reconstruction. This method may be a valuable alternative for reconstruction of entire circumferential avulsion injury of the digits. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.

Concepts: Patient, Skin, Injuries, Forearm, Finger, Arteries of the upper limb, Avulsion injury, Flap

28

The aim of our study was to describe a dorsal distal radius vascularized bone graft pedicled on the posterior interosseous artery (PIA), and its clinical application in 2 cases of ulnar nonunion. We studied the surgical technique in 5 freshly injected cadavers. The 4th extensor compartment artery originates from the anastomotic arch between the posterior division of the anterior interosseous artery and the PIA and provides periosteal branches to supply the dorsal distal radius metaphysis. A 2-cm vascularized bone graft can be harvested from the radius, and dissection of the PIA enables a long pedicle with a wide arc of rotation able to reach the ulnar diaphysis. The approach is limited to the forearm and distal radius and has minimal donor morbidity.

Concepts: Surgery, Forearm, Median nerve, Pronator quadratus, Arteries of the upper limb, Common interosseous artery, Anterior interosseous artery, Posterior interosseous artery

28

PURPOSE: The purpose of this study was to determine functional and subjective results of patients who received arthroscopic debridement for their TFCC Palmer 1B lesions and to compare their results with those of arthroscopic suture repair. METHODS: Between March 2007 and August 2011, 36 patients were diagnosed with Palmer type 1B tears and underwent arthroscopic debridement. 31 patients (15 males and 16 females) were followed up for an average of 26.7 months (±17.4 months) postoperatively. Their average age was 36.7 years (±12.7 years). Follow-up included the determination of range of motion (ROM), grip strength, pain, and wrist scores (modified Mayo wrist score (MMWS), Disabilities of the Arm, Shoulder and Hand questionnaire (DASH score)). RESULTS: Postoperative ROM averaged 99.2 % for the extension/flexion arc, 95.5 % for the radial/ulnar deviation arc, and 99.4 % for the pronation/supination arc of motion when compared with the contralateral wrist. The MMWS was rated excellent in 48 % of patients, good in 39 %, fair in 13 %, and poor in 0 %. The average DASH score was 17.02 (±14.92). There was a significant reduction in pain. The grip strength was 96.7 % (±15.8), pulp-to-pulp pinch 101.9 % (±17.4), and the ulnar variance -0.12 ± 1.69 mm. CONCLUSIONS: Arthroscopic debridement of Palmer type 1B lesions in stable DRUJ yields satisfactory to excellent results. Our study showed similar results compared with the studies of arthroscopic suture repair with shorter postoperative care and fewer complications.

Concepts: Forearm, Wrist, Arthroscopy, Objective pronoun, Grip strength, Distal radioulnar articulation, Triangular fibrocartilage

27

BACKGROUND: Historically, the anterolateral interscalene block-deposition of local anesthetic adjacent to the brachial plexus roots/trunks-has been used for surgical procedures involving the shoulder. The resulting block frequently failed to provide surgical anesthesia of the hand and forearm, even though the brachial plexus at this level included all of the axons of the upper-extremity terminal nerves. However, it remains unknown whether deposition of local anesthetic adjacent to the seventh cervical root or inferior trunk results in anesthesia of the hand and forearm. METHODS: Using ultrasound guidance and a needle-in-plane posterior approach, a Tuohy needle was positioned with the tip located between the deepest and next-deepest visualized brachial plexus root/trunk, followed by injection of mepivacaine (1.5%). Grip strength and the tolerance to cutaneous electrical current in 5 terminal nerve distributions were measured at baseline and then every 5 minutes following injection for a total of 30 minutes. The primary end point was the proportion of cases in which the interscalene nerve block resulted in a decrease in grip strength of at least 90% and hand and forearm anesthesia (tolerance to >50 mA of current in all 5 terminal nerve distributions) within 30 minutes. The primary hypothesis was that a single-injection interscalene brachial plexus block produces a similar rate of anesthesia of the hand and forearm to the published success rate of 95% for other brachial plexus block approaches. RESULTS: Of 55 subjects with blocks placed per protocol, all had a successful block of the shoulder as defined by inability to abduct at the shoulder joint. Thirty-three subjects had measurements at 30 minutes following local anesthetic deposition, and only 5 (15%) of these subjects had a surgical block of the hand and forearm (P < 0.0001; 95% confidence interval, 6%-33%). We therefore reject the hypothesis that the interscalene block as performed in this study provides equivalent anesthesia to the hand and forearm compared with other brachial plexus block techniques. Block failures of the hand and forearm were due to inadequate cutaneous anesthesia of the ulnar (n = 27; 82%), median (n = 26; 78%), or radial (n = 22; 67%) distributions; the medial forearm (n = 25; 76%); and/or the lateral forearm (n = 14; 42%). Failure to achieve at least a 90% reduction in grip strength occurred in 16 subjects (48%). CONCLUSIONS: This study did not find evidence to support the hypothesis that local anesthetic injected adjacent to the deepest brachial plexus roots/trunks reliably results in surgical anesthesia of the hand and forearm.

Concepts: Surgery, Anesthesia, Local anesthesia, Forearm, Ulnar nerve, Local anesthetic, Brachial plexus, Nerve block

27

PURPOSE: The posterior forearm is an excellent donor site for the vascular pedicled cutaneous flaps; yet, there is surprisingly little detailed anatomical information based on clinical decision making. This study was undertaken to evaluate the anatomical basis of the dorsal forearm perforator flaps and to provide anatomical landmarks to facilitate flap elevation. METHODS: Thirty cadavers were available to perform this anatomical study after arterial injection. Twenty fresh cadavers were injected with a modified lead oxide-gelatin mixture, selected for 3-dimensional reconstruction using special software (MIMICS) and the arterial territory measured with Scion Image. Other ten were injected with red latex preparation, and perforators were identified through dissection. RESULTS: (1) The average number of posterior interosseous artery cutaneous perforators in the dorsal forearm was 5 ± 2, the average diameter was (0.5 ± 0.1) mm, and the pedicle length was (2.5 ± 0.2) cm. The average cutaneous vascular territory was (22 ± 15) cm(2). Cutaneous perforators could be found along the line extending from the lateral epicondyle to the radial border of the head of ulna. (2) Dorsal branch of anterior interosseous artery supplied blood to distal third of dorsal forearm; its average diameter was 0.8 mm. CONCLUSION: The free transplantation of the posterior interosseous perforator artery flaps or rotary flap pedicled by dorsal branch of anterior interosseous artery for defect reconstruction is feasible.

Concepts: Blood, Forearm, Pronator quadratus, Arteries of the upper limb, Dissection, Common interosseous artery, Anterior interosseous artery, Posterior interosseous artery