Daniel Greenwald

Free tissue transfer to extend the limits of limb salvage for lower extremity tissue loss

BACKGROUND The extent of tissue loss amenable to primary healing after revascularization is unknown. Salvage of limbs with large soft-tissue defects with exposed tendon, joint, or bone lies beyond the limits of conventional techniques. We report our results using free tissue transfer as an adjunct to lower extremity vascular reconstruction in patients with complex ischemic or infected wounds. METHODS Retrospective chart review of patient and wound characteristics. RESULTS From January 1992 to June 1996, 585 procedures were performed in 544 patients, including 27 free flaps in 26 patients: 17 free flaps combined with distal bypass (7 staged, 10 simultaneous) and 10 isolated free flaps. Flap donor sites included radial forearm (8), latissimus dorsi (7), rectus abdominus (9), and scapula (3). Surgical indications included extensive ischemic/neurotrophic ulcers, and nonhealing vein graft harvest incision or transmetatarsal amputation site. Mean area of tissue loss was 70 cm2, mean ulcer duration was 5 months, and 92% of patients had exposed tendon, joint, or bone. During a mean follow-up of 14 months, 2 patients died of cardiopulmonary disease and 3 flaps failed, resulting in below-knee amputation. Six flaps were revised for graft stenosis (1), venous thrombosis (1), or flap edge necrosis (4). Limb salvage rate was 70% at 24 months by life-table analysis. Functional ambulation was achieved in 21 of 24 (88%) patients, including 7 of 8 with diabetes, end-stage renal disease, and heel ulcers. CONCLUSION In select ambulatory patients with large soft-tissue defects and exposed deep structures, functional limb salvage is obtainable in more than 80% of patients. For lesions not amenable to vascular reconstruction with conventional methods of wound coverage, free tissue transfer extends the limits of limb salvage and is a viable alternative to amputation.

Metacarpal fracture angulation decreases flexor mechanical efficiency in human hands.

&NA; The most common fracture of the hand occurs at the neck of the metacarpal. Despite clinical studies, controversy remains as to how much fracture angulation should be tolerated before more aggressive reduction is required. A controlled biomechanical model was used to simulate fifth metacarpal head fractures in fresh human cadaveric hands. Fracture angulation was varied from 0 to 90 degrees at 10‐degree intervals. We measured tendon excursion, tendon load, and work required to flex the small finger from full extension to full flexion with 10‐degree incremental increases in vertex‐dorsal angulation. Repeated measures analysis of variance revealed a significant decay in the efficiency of the flexor system when fracture angulation exceeded 30 degrees. Tendon excursion, load, and work requirements were all increased, confirming the detrimental effect of excessive fracture angulation on hand mechanics and function.

Dynamic analysis of profundus tendon function

A method for analysis of hand function is reported through evaluation and characterization of flexor digitorum profundus (FDP) tendon mechanics. A testing platform is used that allows for the dynamic evaluation of intact cadaver hand mechanics under normal and pathologic conditions using simultaneous measurements of tendon load, tendon excursion, grip strength, pinch strength, and joint angle. This study of FDP tendons in normal fresh cadaver hands demonstrates that FDP tendon excursion increases as the number and size of joints flexed increases. Extensor counterweighting 500 g, increases FDP tendon load and work but not excursion requirements, and FDP loads of up to 75 N are required for single finger grip strengths of 4 kg force. These loads do not result in permanent (plastic) deformation of either the tendon or the restraining soft tissues. Detailed descriptions of the platform and the mechanical tests performed are provided.

Mechanical analysis of tendon suture techniques

The relative strengths of seven methods of tendon repair were measured by mechanical disruption in an effort to determine the quality of a technique using loaded criss-crossing sutures and a running epitenon stitch. Fifty-seven calcaneus tendons were harvested from adult New Zealand white rabbits and randomized for transection. Standardized oblique transections were repaired with nylon using modified Halsted peripheral suture; modified Kessler technique; Kessler core stitch alone; running peripheral epitenon stitch; modified Becker technique #1; modified Becker technique #2; and a new augmented Becker repair. Sixteen additional rabbits each had bilateral tendon repairs in situ, one leg by Kessler and the other by the new augmented Becker repair technique. Half were lethally injected after 2 weeks and half after 4 weeks. Tenorrhaphies were pulled apart at constant speed until a gap of 1 mm was observed. Strength (maximum stress) and toughness (energy absorption to gap formation) were calculated. At time 0 the new augmented Becker repairs were the strongest, followed by the Kessler and Becker #2 tenorrhaphies. Kessler repairs were weaker at 2 weeks and then gained in strength; new augmented Becker repairs did not weaken at the 2-week point and demonstrated significant gains in strength after 4 weeks in vivo. The new augmented Becker repair was the strongest by a significant margin at all time points.

Debilitating silicone granuloma of the penis and scrotum.

The restoration and improvement of body contour have intrigued surgeons for over 100 years, generating much interest in the subcutaneous/intradermal injection of highly viscous fluids. The local complications of liquid silicone injection have been well documented over the past 30 years. Although Dow-Corning has not made medical-grade liquid silicone available for use in humans without an approved research application since 1966, practitioners, both licensed and unlicensed, have administered these injections worldwide for a variety of indications throughout the body. There is little or no information concerning the adulteration of these injectates. To date, there have been four case reports of penile injections--the indications being evenly split between the treatment of impotence/sexual inadequacy and augmentation. The most recent description was published in 1982. We present a case of debilitating silicone granuloma of the penis and scrotum secondary to large-volume injections into the corpora cavernosae and penile soft tissues administered in Belgium 14 years prior to presentation. The development of a silicone foreign body reaction, massive edema, and subsequent impotence lends itself to a clinical diagnosis and aggressive treatment with wide local excision and appropriate soft-tissue coverage. The metabolic fate of silicone in vivo remains inadequately characterized and a fertile area for research as new methods involving nuclear magnetic resonance spectroscopy have been devised to identify silicone and highly coordinated silicone complexes.

Biomechanical analysis of four-strand extensor tendon repair techniques

Experience with flexor tendon repairs has suggested the superiority of the augmented Becker (MGH) technique for strength, toughness, and gap resistance. In an effort to apply these findings to the extensor tendons, 3 four-strand extensor tendon repair techniques were biomechanically tested in fresh human cadaver limbs: modified Bunnell, modified Krackow-Thomas, and MGH. Repairs were performed in Verdans zone VI. Repaired tendons were distracted at constant speed until rupture. Tendon load and tendon distraction were continuously monitored. Benchmark values for load were measured as fingers were pulled from full metacarpophalangeal (MP) joint flexion to full extension, to 1-mm gap formation at the tenorrhaphy, and to complete rupture of the repair. The MGH repair proved significantly more resistant to gap formation (stronger and tougher) than the Bunnell and Krackow-Thomas repairs (p < .02). No differences were seen between groups in repair performance at MP joint extension and at complete rupture. This study suggests that the MGH technique has superior gap resistance to the other four-strand methods tested for extensor tendon repair in Verdans zone VI. The MGH repair is recommended for extensor tendon repairs in zone VI when early postoperative motion regimens are considered.

Augmented becker versus modified kessler tenorrhaphy in monkeys: Dynamic mechanical analysis

The strength and gliding efficiency of an augmented Becker and Kessler tendon repair techniques were compared in fresh cadaver macaque monkey hands. Gliding efficiency was determined by comparing tendon work and load measurements made during tendon excursion to full fist with the same measurements made after tendon repair. Repair strength was then determined by tendon distraction to complete repair rupture. Data were gathered by computer controlled tensiometer and analyzed by factorial and repeated measures ANOVA. The augmented Becker repairs were significantly stronger than Kessler repairs. Repaired tendons required more load and work to bring the fingers into full fist; both repair types resulted in gliding efficiencies of 30% compared to intact controls. The augmented Becker repair is significantly stronger in situ than the modified Kessler and is recommended when early postoperative motion regimens are planned.

Anatomy, physiology, and functional restoration of the thumb.

The essential prehensile nature of the human hand rests on the presence of a mobile, sensate thumb with adequate stability and length. The true significance of the thumb-to-hand function is variable and dependent on a persons vocation, expectations, and needs. The frequently stated opinion that the thumb represents 40% of hand function is too exacting and does not allow for flexibility in evaluating a patients requirements after thumb injury or loss. It is our approach to consider each patients specific needs for individualized planning of thumb reconstruction. The patient can often offer useful information regarding need for strength vs. precision, width of hand vs. requirements for fine motor function, and concern for the aesthetic nature of an abnormal thumb vs. the variable deformities resultant from thumb reconstruction. We offer a review of the basic anatomy and physiology of the human thumb, with emphasis on hand-and-thumb function. We present the alternatives for thumb reconstruction, the advantages and disadvantages, and the relationships to a specific patients needs. Clinical examples of various methods of thumb reconstruction, including metacarpal lengthening, phalangization, osteoplastic reconstruction, pollicization, and toe-to-hand transfer are provided.

An algorithm for early aggressive treatment of frostbite with limb salvage directed by triple-phase scanning

&NA; Frostbite injuries have traditionally been treated with expectant observation. With the exception of early blister aspiration tissues are allowed to demarcate before definitive debridement is accomplished. Triple‐phase bone scanning has been used to define the extent of fatally damaged tissues in an attempt to allow for early debridement and wound closure. We suggest extending this technology to assess injury and direct debridement in patients for whom early aggressive salvage attempts are indicated. We present two cases in which triple‐phase scanning was used to direct early debridement for aggressive limb salvage with flap reconstruction. Bone, ligament, tendon, and nerve were preserved and covered with vascularized tissue before the onset of frank necrosis. Postoperative scans reveal revascularization of these tissues. An algorithm incorporating triple‐phase scanning for the evaluation and treatment of frostbite is presented. (Plast. Reconstr. Surg. 102: 1069, 1998.)

Efficiency of the flexor tendon pulley system in human cadaver hands

The efficiency of the flexor tendon system was examined in a human cadaver model. Pulleys were randomly sectioned, and the results were evaluated on the basis of the tendon excursion, force generated at the fingertip, and the work (force multiplied by distance) involved, as compared to the intact pulley system. When a single minor pulley (A1 or A5) was cut, there was no statistical difference in work efficiency or excursion efficiency from controls. Cutting all minor pulleys (A1, A3, A5) lead to a significant loss in excursion efficiency. The intact three pulley systems of A2, A3, and A4 were near normal and statistically better than A2 and A4 together for work efficiency. Cutting one of the major pulleys (A2, A4) resulted in significant changes in efficiency, but what was unexpected was to find an 85% loss of both work and excursion efficiency for the loss of A4 but only an excursion difference of 94% for the loss of A2. Our findings demonstrated that in this model, with the influence of the skin removed, A4 absence produced the largest biomechanically measured efficiency changes and that a combination of A2, A3, and A4 was necessary to preserve both work and excursion efficiency.