Satoshi Usami

Histological investigation of common insensate flaps obtained from the hand and forearm regions for use in fingertip reconstruction.

Abstract Objective: Many skin flaps have been described for fingertip reconstruction; however, they have not been compared histologically. The aim of this study is to compare the histological features of common insensate flaps that are used for fingertip reconstruction. Method: Skin from fingertips and common flap donor sites on the hand and forearm of cadavers were harvested. This study investigated four histological characteristics, namely thickness of the epidermis and dermis; the ratio of collagen to elastic fibres (C/E ratio) in subdermal tissues, and distribution densities of Merkel cells and Meissner’s corpuscles. It then compared the values obtained to determine which flap donor site best matched the fingertip. Results: Epidermal thickness of the reverse digital artery island flap, thenar flap, and hypothenar flap was similar to that of fingertip tissue; dermal thickness of the hypothenar flap was similar to that of fingertip tissue. The C/E ratio of the reverse digital artery island flap was similar to that of fingertip tissue. Merkel cells were abundant in the reverse digital artery island flap, but Meissner’s corpuscles were few in each of the flaps compared with fingertip tissue. Conclusion: The flap donor site with histological properties most similar to fingertip tissue was the palmar lateral aspect at the finger base, representative of the reverse digital artery island flap with respect to epidermal thickness, C/E ratio, and presence of Merkel cells. The thenar and hypothenar flaps also showed similar properties.

Coverage of the dorsal surface of a digit based on a pedicled free-style perforator flap concept

BACKGROUND Reconstruction of the finger and thumb dorsum has been considered difficult because of the need for a thin and flexible flap, and the surrounding tissue is sometimes insufficient for a local flap. The purpose of this report is to describe our concept for finger and thumb dorsum reconstruction with free-style perforator flaps and our clinical experience with transfer of various perforator flaps. METHODS Thirty-two finger dorsum defects in 32 patients were covered with pedicled free-style perforator flaps. The perforator origin was a digital artery perforator in 22 cases and a dorsal metacarpal artery perforator in 10 cases. The flap style was advancement type in 11 cases, rotation in 2, propeller in 14, and adipofascial in 5. RESULTS The mean size of the digital artery perforator flap was 3.4 cm2 and that of the dorsal metacarpal artery perforator flap was 7.9 cm2. All flaps, except for two propeller flaps with 180 degrees rotation, survived completely. These flaps were of elongated style, and the length-to-width ratios were approximately 3:1 and 3.5:1, respectively. CONCLUSIONS There are multiple perforators in the finger and thumb dorsum region from the proper digital artery, which are suitable for pedicled free-style perforator flaps. These perforators increase flap flexibility and reliability in clinical applications.

A retrospective study of closed extension block pinning for mallet fractures: Analysis of predictors of postoperative range of motion

BACKGROUND Extension block pinning is a simple and reliable technique for mallet fractures, but poor results are sometimes obtained. The predictors of postoperative range of motion after extension block pinning of mallet fingers were investigated. METHODS The outcomes for postoperative active motion of the distal interphalangeal (DIP) joint, such as flexion angle, extension loss, and total range of motion, were examined. Predictors such as age, gender, finger, fragment size, joint subluxation, the time from injury to operation, procedure, fixation angle, the time from operation to wire removal, and joint step-off were evaluated statistically. RESULTS With a mean 12.2-month follow-up, according to Crawfords criteria, 49 of 116 fingers (42%) had an excellent result, 37 (32%) had a good result, 29 (25%) had a fair result, and 1 (1%) had a poor result. The mean flexion angle was 62.9 ± 13.2°, extension loss was -6.6 ± 7.3°, and total range of motion was 55.8 ± 17.0° in the DIP joint. Pin tract infections were confirmed in 7 fingers with poor results. There were no complaints about nail deformity or skin abnormality. On multivariate analysis, significant predictors of poor postoperative motion were increased age chronic case, remained joint step-off, excess flexed fixation angle, and long-term wire placement. CONCLUSIONS Extremely flexed fixation and chronic case easily causes extension loss in the DIP joint. In closed extension block pinning, joint fixation with an extreme flexion angle should be avoided and the pinning wire should be removed as soon as possible after confirming bony union.

The possibility of free tissue transfer as a nutrient flap for critical ischemic foot: A case report

Microsurgical procedure of free tissue transfer in critical limb ischemia patients with large ulceration has already been established. The nutrient flap concept was that transferred tissue functioned not only to cover the skin defect but also as a supplementary blood supply to the ischemic lower leg. This report showed the justification for this concept, which was rarely discussed. A 58‐year‐old male patient with progressive forefoot gangrene caused by arteriosclerosis obliterans was presented. The distal bypass procedure was performed as revascularization surgery, and a latissimus dorsi (LD) myocutaneous flap was transplanted to cover ulceration. The arterial pedicle of the flap was anastomosed to the vein graft in an end‐to‐end manner, and the venous pedicle was anastomosed to the posterior tibialis vein in an end‐to‐end manner. Bypass graft blood flow went straight to the LD flap only. The postoperative course was uneventful. The free flap and right foot survived successfully and the patient was ambulatory with no recurrence of ulceration wearing order‐made shoes more than three years after transplantation. Vessel‐selective angiography was performed two months after surgery. An angiographic catheter was inserted into the bypass graft, which ran straight through the flap nutrient artery. The results obtained showed that not only the transferred flap area, but also the remaining original foot soft tissue (including the sole and heel) was clearly visualized radiologically only through the flap nutrient vessel. This findings of the angiography appear to provide direct evidence for the nutrient flap concept.

Vascularized Nerve Bypass Graft: A Case Report of an Additional Treatment for Poor Sensory Recovery

Summary: End-to-side neurorrhaphy has proven effective in basic research and in clinical application. One of the methods of end-to-side neurorrhaphy, nerve bypass technique, has been reported and axon regeneration has been proven. In clinical application, the utility of the nerve bypass technique has been revealed in some cases; however, these bypasses were performed using nonvascularized nerves. We initially used the vascularized nerve bypass graft technique with the sural nerve as a secondary clinical procedure after median nerve injury in a 61-year-old patient and achieved motor and sensory nerve regeneration, as supported by a nerve conduction study and clinical sensory test. This technique has the potential to become one of the choices for salvage procedure of severe nerve injury.

Extensor Digiti Minimi Transfer for the Treatment of an Unstable Metacarpophalangeal Joint in Thumb Polydactyly Without Thenar Atrophy

Dear Sir, As treatments for the laxity of metacarpophalangeal (MCP) joint in hypoplastic thumb, joint capsular plication, free tendon graft or MCP arthrodesis have been performed [1]. In addition, transfer of abductor digiti minimi [2] or ring finger flexor digitorum superficialis [3] have been used to provide thumb opposition and restore MCP joint stability. In the present case, we used extensor digiti minimi (EDM) transfer to treat MCP joint instability due to ulnar collateral ligament laxity in a patient with thumb polydactyly without thenar muscle atrophy. An 11-year-old girl who was naturally right thumb polydactyly with floating ulnar thumb had a thumb plasty at the age of five. But she was bothered by an unstable MCP joint due to ulnar collateral hypoplasia (Fig. 1a). Six years later from primary operation, she underwent a second surgery to improve joint instability and outer appearance of the thumb. The MCP joint instability was corrected by an EDM transfer, which involved fasting the end of the transferred tendon to the ulnar side of the MCP joint at the bottom of proximal phalanx and at the metacarpal head (Fig. 2). At 10 months postoperatively, the appearance of the thumb was improved and the MCP joint was stable (Fig. 1b). The EDM transfer procedure was initially reported for restoration of thumb adduction in ulnar nerve paralysis [4], but MCP joint stability could be achieved by changing the distal tendon insertion as this case. We consider there are some advantages to this procedure: 1) the MCP joint achieves maximum stability in the opposite position, because the tension of the transferred EDM tendon increases with the increase in the angle of opposition, 2) the mobility of the MCP joint is not impaired, 3) the strength of side pinch could be increased by increasing the thumb adduction force. On the other hand, the disadvantages of this procedure include that this transfer would position thumb in extension and adduction, and a decrease in the extension force of the little finger. The former demerit barely mattered in actuality, because we think the tension of transferred EDM is not strong in the rest position.

Intraoperative ultrasound-assisted repair of zone III flexor tendon rupture with a minimal incision.

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Primary On-top Plasty for Treatment of Short-type Postaxial Polydactyly of the Foot.

BackgroundPostaxial polydactyly of the foot is typically treated with medial or lateral toe ray resection. However, simple ray resection does not always give a natural postoperative appearance, especially for short-type polydactyly. The purpose of this article was to describe our primary operation with on-top plasty for lengthening of short-type postaxial polydactyly. MethodsFour patients (mean age, 11.3 months) underwent this procedure. Ray transfer was performed at the proximal phalangeal level. Lateral distal and middle phalanges were resected and the medial ray was transferred on top of the remaining lateral proximal phalanx. Preoperative and postoperative toe lengths and complications were evaluated by comparison with the contralateral side on x-ray. ResultsAll toes were lengthened by a mean of 115.1% from the tip of the distal phalanx to the bottom of the proximal phalanx relative to contralateral side. Appearances were very natural without valgus deformity and hypertrophic scar. And there was no remaining dysfunction in walking after a mean of 21.5 months follow-up. ConclusionsThis on-top procedure is useful for improving toe lengthening and bone alignment correction with minimal functional disturbance.

POSTOPERATIVE VOLUMINAL FLAP REDUCTION AFTER FINGERTIP RECONSTRUCTION USING THE REVERSE DIGITAL ARTERY ISLAND FLAP

A total of 16 fingers of 16 patients were subjected to fingertip reconstruction using the reverse digital artery island flap (RDAIF). We evaluated the influences of postoperative flap congestion, initial harvested flap size, patients age and smoking habit on postoperative final flap size and postoperative range of total active motion (TAM) in affected fingers at a mean interval of 11.4 months. In the results, final flap size and TAM showed a tendency to decrease with increase in the initial harvested flap size and age. Eventually, the final flap size moved towards the size of the fingertip defect. Factors of flap congestion and smoking habit had little influence on the change in flap size and TAM. In conclusion, wide harvested flaps showed significant postoperative reduction in size compared with the small flaps, and extensive skin defect after flap harvest caused a decrease in postoperative TAM. Thus, the size of the harvested RDAIF should be comparable to that of the fingertip defect to prevent postoperative decrease in range of motion in affected fingers, and indication of this flap to the elderly needs to be considered.