Extensor digitorum brevis free flap: anatomic study and further clinical applications

The extensor digitorum brevis muscle flap is reliable, safe, and can be used either as a pedicle or as a free flap with minimal donor site morbidity. To increase the existing knowledge of this flap and to establish further anatomic basis for the design and elevation of the extensor digitorum brevis flap, 26 specimens from 13 fresh cadavers were dissected under 3.5x loupes. The lateral tarsal artery was found to be the main blood supply to the muscle. It has an average diameter of 1.83+/-0.35 mm and a length of 1.89+/-0.69 cm. The dorsalis pedis artery has, at the level of the lateral tarsal artery takeoff, a diameter of 3.25+/-0.62 mm. From this point to the origin of the deep plantar branch, the dorsalis pedis artery has minimal branching, and the surgeon has available an artery homogeneous in diameter that is 6.77+/-0.99 cm in length. Related neurovascular structures (anterior tibial artery and the venae comitantes, dorsalis pedis and first dorsal metatarsal artery, and deep peroneal nerve) were also studied. A safe and reliable harvesting technique and the "T interposed extensor digitorum brevis" technique for sparing the anterior tibial artery are presented, as are clinical case examples on the use of this flap as a flow-through, extensor digitorum brevis-vascularized nerve graft, a combined extensor digitorum brevis-deep peroneal nerve graft, and a bilobed extensor digitorum brevis-dorsalis pedis fasciosubcutaneous free flap.     

The dorsalis pedis myofascial flap

A modification of the dorsalis pedis artery island flap is presented. In this modification, the deep fascia of the dorsum of the foot with part or the whole of the extensor digitorum brevis muscle is used as a fascial or myofascial flap supplied by the dorsalis pedis artery and covered by a split-thickness skin graft. The purpose is to decrease the morbidity of the donor site, which is closed by direct sutures without skin grafting. Four cases are reported with minimal donor-site morbidity and full survival of the flaps. The mean follow-up period is 17 months.     

Transfer of vascularized extensor tendons from the foot to the hand with a dorsalis pedis flap

The use of the dorsalis pedis flap with vascularized extensor tendons was presented. An anatomic study has been carried out that has shown that the vascularization of the foot extensor tendons can be exclusively dependent on the blood contribution coming from the dorsalis pedis artery. In two cases that are presented and followed up for over a year after the surgery, the functional results obtained are good in the hand and aesthetically acceptable in the foot.     

The extensor digitorum brevis as a muscle island flap

The use of the extensor digitorum brevis muscle as a local muscle island flap for the coverage of the soft-tissue defects in the region of the lateral malleolus is presented. The anatomy of the muscle, the donor dissection, and the utilization of the extensor digitorum brevis muscle as a local muscle flap in the lower extremity are discussed. This flap was used successfully in a patient with a wound over the lateral malleolus and ankle.     

Comparative anatomy of the arterial system of the foot in primates. 1. Macaque

Using stereoscopic angiography, the entire arterial system of the foot of the macaque was analyzed. The arteria saphena, instead of the a. tibialis anterior, reaches the dorsum of the foot, and its branches supply most of the foot. The dorsal arteries are dominant as far as the metatarsal spaces of the lateral four toes. The a. metatarsea dorsalis II showed a tendency to be the single dominant artery and to give rise to even the a. digitalis communis plantaris IV through the catella plantaris distalis. This tendency was observed more clearly in other macaques species than the Japanese monkey. The perforating branch at the second proximal metatarsal space forms the arcus plantaris profundus, which is accompanied by the deep branch of the nervus plantaris lateralis. Beneath the arch, the catella plantaris proximalis is formed on the metatarsal bones among the perforating branches of the aa. metatarseae dorsales. The a. tibialis posterior forms the arcus plantaris superficialis, whose thin branches commonly enter the aa. digitales communes plantares.     

Free flap to the arteria peronea magna for lower limb salvage

A 36-year-old woman sustained an amputation of her right leg at the thigh level and a degloving injury of her left foot and ankle region in an accident during a suicide attempt. Primarily, her left foot was covered with a split skin graft, resulting in a soft-tissue defect at the medial malleolus and at the calcaneus bone. Reconstruction was planned with a free latissimus dorsi muscle flap. Preoperative examinations revealed an arteria peronea magna with a hyperplastic peroneal artery solely providing arterial blood supply to the foot. The arteria peronea magna divided into two branches proximal to the upper ankle joint, replacing the dorsal pedis artery and the medial plantar artery. Tibial posterior and tibial anterior arteries were hypoplastic-aplastic. Microvascular end-to-end anastomoses of the flap vessels to the medial branch ("medial plantar artery") of the arteria peronea magna and its concomitant vein at the medial malleolar bone level were successfully performed. The postoperative course was uneventful. Four weeks postoperatively, the patient started walking assisted by a prosthesis on her right thigh stump. This experience demonstrates that even in a case of arteria peronea magna, free flap surgery for lower limb salvage is a reliable and worthwhile method.     

Studies on the tendinous compartments of the extensor muscles on the back of the human hand and their tendon sheaths. I

In 47 dissected right and left hands of adults of both sexes, kept in a moist condition, significant practical-clinical investigations of the transitional zone between forearm and hand were undertaken. In particular it was sought to determine the characteristic sizes of the extensor retinaculum, the osteofibrous tunnels, the insertion tendons of the hand and finger extensor muscles, and their tendon sheaths. Together with the palmar carpal ligament, the 2 to 3 cm wide extensor retinaculum annularly surrounds the whole circumference of the carpus. It extends obliquely from radial-proximal to ulnar-distal and conducts the extensor tendons over the carpal articulations. According to recent studies, it is divided into a superficial and a deep fibrous layer. From the undermost surface, vertical and oblique septa run to the plane of the forearm and carpal bones. They separate the fibrous portion of the 6 tendinous compartments of the dorsum manus. In 8.5% of cases, an accessory and completely independent tunnel of the extensor pollicis brevis muscle exists in the material investigated, and in 2.2% of cases, there is an additional tunnel for the extensor carpi radialis muscle. Hence, one occasionally finds 8 separate osteofibrous gliding compartments for the extensor muscles in the dorsal hand region. The longest tunnel belongs, as a rule, to the extensor digiti minimi muscle, whilst the widest pertains to the extensor digitorum muscle. Within the tunnel and also proximal and distal to it, the extensor tendons are surrounded by synovial sheaths. Because of its wide encroachment on the dorsum of the hand, the insertion tendon of the extensor digiti minimi muscle possesses the longest tendon sheath, measuring 68.8 mm. The next longest sheath, that of the extensor pollicis longus muscle, which measures 56.2 mm, begins further proximal to the gap of the radiocarpal articulation. In 12.8% of cases, there are divided sheaths of the abductor pollicis longus and of the extensor pollicis brevis muscle. The tendon sheath of both extensor carpi radiales muscles is frequently divided into 2 compartments which, in 2/3 of cases, communicate. The compartment of the extensor carpi radialis brevis muscle, in 91.5% of cases, shares a window-like opening with the roof of the synovial vagina of the extensor pollicis longus muscle. The tendon sheath of the long extensor muscles of the fingers originates 5 mm proximal to the forearm border of the extensor retinaculum and has a communal recess. The IVth tendon sheath opens distally and splays out in a glove-like manner to some distal recesses.(ABSTRACT TRUNCATED AT 400 WORDS)     

Estimation of instantaneous moment arms of lower-leg muscles

Muscle moment arms at the human knee and ankle were estimated from muscle length changes measured as a function of joint flexion angle in cadaver specimens. Nearly all lower-leg muscles were studied: extensor digitorum longus, extensor hallucis longus, flexor digitorum longus, flexor hallucis longus, gastrocnemius lateralis, gastrocnemius medialis, peroneus brevis, peroneus longus, peroneus tertius, plantaris, soleus, tibialis anterior, and tibialis posterior. Noise in measured muscle length was filtered by means of quintic splines. Moment arms of the mm. gastrocnemii appear to be much more dependent on joint flexion angles than was generally assumed by other investigators. Some consequences for earlier analyses are mentioned.     

The free vastus lateralis flap: an anatomic study with case reports.

The suitability of the thigh as a donor site for a new free flap was examined in 100 cadavers. It was found that the vastus lateralis muscle can be used to form a myocutaneous or fasciomuscular flap, the raising of which causes no technical problems and leads to no functional and only minor aesthetic impairments. Depending on the muscle segment from which the flap is raised, a neurovascular pedicle measuring between 8 and 20 cm with a diameter of 2 to 2.5 mm (artery) or 2.5 to 4 mm (vein) can be formed. The skin island in the myocutaneous flap measures on average 8 x 16 cm and is located above the middle portion of the muscle. The diameter of the supplying perforator vessel is between 0.7 and 1.2 mm. The flap can be raised parallel to head and neck surgery and applied as a myocutaneous flap for coverage of extensive or perforating defects or intraorally as a fasciomuscular flap.     

Vascular anatomy of the forearm muscles: a study of 50 dissections

This anatomic study is based on 50 adult cadaver upper extremities. The general disposition of the forearm arteries and muscles and the main anatomic variations encountered are specified. Constant existence of an "anterior oblique artery" satellite of the pronator teres was established. The median nerve artery was principally dedicated to the flexor digitorum superficialis and participated appreciably in the constitution of palmar arches in only one case. A supernumerary intermedial radial muscle was found only in two cases. The abductor pollicis longus and extensor pollicis brevis appeared as a single muscular and vascular unit in 84 percent of cases. All the arteries destined for muscles were reckoned whatever their caliber might be. Despite its limitations, this study confirms the very great number of the forearm muscular pedicles. Each forearm contained an average of 264 muscular vascular pedicles. The systematization of the origins and destinations of the 13,158 muscular pedicles is described in a numbered manner for each of the 20 normal forearm muscles and for each of the 12 studied arterial segments. The pronator teres was likely to be supplied by all the anterior arteries of the upper limb. The flexor carpi radialis had one or two dominant pedicles originated from the recurrens ulnaris anterior, recurrens ulnaris, or ulnaris-interossea communis arteries, and many transversal branches originated from the radial artery. The flexor carpi ulnaris was supplied in its proximal third by the recurrens ulnaris posterior artery and in its distal two-thirds by many branches of ulnar artery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of the free dorsalis pedis flap in head and neck repairs.

Many defects of the head and neck can be readily repaired with a free dorsalis pedis flap, and we report success with these flaps in 9 of 12 cases. A precise knowledge of the anatomy of the arterial supply of the flap is necessary. Preoperative arteriography is recommended if the dorsalis pedis artery is not easily palpable, or if an anomalous distribution of the artery along the dorsum of the foot is sus pected. However, the transfer of the flap should be delayed for two weeks after preoperative arteriography is performed. The one-stage soft tissue reconstruction with a free dorsalis pedis flap has been associated with minimal morbidity and good acceptance by patients. A delay procedure for the flap seems to enhance the chances of complete survival which is so necessary in the repair of intraoral and pharyngeal defects. Careful attention to details and close monitoring of the flap will minimize morbidity. In case of an early failure of a flap, a secondary reconstruction by a different flap can be done in the first 48 to 72 hours. Early postoperative radiotherapy has been well tolerated over these free flaps.     

Upright posture of the human and the morphologic evolution of the musculi extensores digitorum pedis with reference to evolutionary myology

A brief literature review is made of the morphological changes in the bones of the lower limbs of man, which are the result of his upright walk. The author's task has been to study the morphological changes of Mm. extensores digitorum pedis from the viewpoint of evolutionary myology. The following material has been studied: Lower limbs of adults, 151 less than or equal to N less than or equal to 358. Pelvic limbs of Marsupialia, Insectivora, and non-hominide primates; N = 122. Lower limbs of human embryos and fetuses; N = 71. The following acknowledgements are the author's own studies. They begin with an evolutionary-myological study of m. extensor hallucis longus and of m. extensor digitorum longus, together with m. peroneus tertius.     

Bupivacaine myotoxicity is mediated by mitochondria.

We have investigated the effects of the myotoxic local anesthetic bupivacaine on rat skeletal muscle mitochondria and isolated myofibers from flexor digitorum brevis, extensor digitorum longus, soleus, and from the proximal, striated portion of the esophagus. In isolated mitochondria, bupivacaine caused a concentration-dependent mitochondrial depolarization and pyridine nucleotide oxidation, which were matched by an increased oxygen consumption at bupivacaine concentrations of 1.5 mm or less at pH 7.4, whereas respiration was inhibited at higher concentrations. As a consequence of depolarization, bupivacaine caused the opening of the permeability transition pore (PTP), a cyclosporin A-sensitive inner membrane channel that plays a key role in many forms of cell death. In intact flexor digitorum brevis fibers bupivacaine caused mitochondrial depolarization and pyridine nucleotides oxidation that were matched by increased concentrations of cytosolic free Ca(2+), release of cytochrome c, and eventually, hypercontracture. Both mitochondrial depolarization and cytochrome c release were inhibited by cyclosporin A, indicating that PTP opening rather than bupivacaine as such was responsible for these events. Similar responses to bupivacaine were observed in the soleus, which is highly oxidative. In contrast, fibers from the esophagus (which we show to be more fatigable than flexor digitorum brevis fibers) and from the highly glycolytic extensor digitorum longus didn't undergo pyridine nucleotide oxidation upon the addition of bupivacaine and were resistant to bupivacaine toxicity. These results suggest that active oxidative metabolism is a key determinant in bupivacaine toxicity, that bupivacaine myotoxicity is a relevant model of mitochondrial dysfunction involving the PTP and Ca(2+) dysregulation, and that it represents a promising system to test new PTP inhibitors that may prove relevant in spontaneous myopathies where mitochondria have long been suspected to play a role.     

Forearm compartment syndrome: anatomical analysis of surgical approaches to the deep space

Forearm compartment syndrome is a surgical emergency that usually requires release of the superficial muscle compartments. In some clinical situations it is imperative to also explore the deep muscle compartments. There are no anatomical guides for surgical exploration of the deep compartments that would minimize collateral damage to surrounding vessels, nerves, and muscles. Surgical injury in the setting of ischemia, especially vascular injury, compounds the tissue damage that has already occurred. The authors evaluated four surgical approaches (three volar and one dorsal) to the deep forearm by performing detailed anatomical dissections on 10 embalmed and plastinated cadavers. They used a scoring system to rate the approaches for their ability to visualize the deep space without causing iatrogenic injury to superficial muscles, arteries, and nerves. In the volar forearm, an ulnar approach to the deep space is simple, causes the least iatrogenic surgical injury, and provides access to the deep volar forearm structures. The plane of dissection is between the flexor carpi ulnaris and the flexor digitorum superficialis. Dividing one or two distal segmental branches of the ulnar artery to the distal flexor digitorum superficialis exposes the pronator quadratus. Lifting the ulnar neurovascular bundle with the flexor digitorum superficialis in the middle third of the forearm exposes the flexor digitorum profundus and the flexor pollicis longus. This approach to the deep space requires no sharp dissection. In the dorsal forearm, a midline approach between the extensor digitorum communis and the extensor carpi radialis brevis is simple and safe.     

The anatomic basis for the platysma skin flap

Meticulous anatomic dissection of the vasculature of the superficial anterolateral neck indicates that the platysma and overlying skin are supplied by direct cutaneous arteries measuring 0.5 mm in diameter. The small arteries are branches of the postauricular and occipital arteries in the upper lateral neck, the facial and submental arteries in the upper medial neck, the superior thyroid artery in the middle of the neck, the subclavian artery in the lower medial neck, and the transverse or superficial cervical arteries in the lateral aspect of the neck. These vessels traverse the undersurface of the platysma muscle to provide blood flow to the overlying skin. As opposed to this direct cutaneous system, the myocutaneous blood supply perforating through the sternocleidomastoid is scant. The platysma skin flap will survive if the blood supply from at least one region is preserved. In addition, it may be beneficial to include the external jugular and/or the communicating veins in the flap. By following these guidelines, the platysma flap has been successfully used for facial reconstruction in 7 of 8 consecutive patients.     

Extensor digitorum brevis as an island flap in the reconstruction of soft-tissue defects in the lower limb

The extensor digitorum brevis island flap is a versatile and robust flap able to provide adequate bulk and coverage in soft-tissue defects of the lower limb. The donor-site deformity is limited to the necessary scar needed to approach and rotate the muscle. An anatomic study was performed in 10 fresh cadavers and consisted of two parts: study of the muscle flap itself, and examination of skin vascularization. Methylene blue and Salmon's mass (radiopaque) were injected through the three main arteries of the leg. Muscle and cutaneous staining were noted. Clinical applications of this flap are reported. These resulted in successful healing of the defect with good aesthetic and functional results on both recipient and donor sites. Long-term follow-up was maintained for up to 21 months.     

The extensor digitorum brevis muscle island flap for soft-tissue loss around the ankle

The extensor digitorum brevis muscle flap, which has already been suggested as a local flap for the foot, has been applied by us in 2 cases with excellent results. This flap, as with other muscle flaps, provides an excellent bed for the skin graft. Furthermore, because of its width, it allows for covering an area of skin loss 5 X 7 cm in size in areas that are difficult to cover by other reconstructive means. The arch of rotation of this flap allows for coverage of the lateromedial and posterior surfaces of the ankle with no functional loss at the donor site. The relative ease of elevating this flap presents a reasonable justification for its wider application as a single local procedure for skin problems around the ankle.     

Management of secondary soft-tissue deficits following microsurgical head and neck reconstruction by means of another free flap

Secondary soft-tissue deficits may develop following a microsurgical reconstruction in the head and neck region because of inadequate planning or chronic effects of radiotherapy. Although most cases could be managed with alternative methods, free flaps might be necessary in difficult cases. Herein are described 11 cases of microsurgical head and neck reconstruction in which secondary soft-tissue deficits required transfer of another soft-tissue free flap. All patients had malignant tumors treated with surgical resection, and their defects were reconstructed with free flaps. Seven patients received either preoperative or postoperative adjunctive radiotherapy. These patients gradually developed signs and symptoms of soft-tissue deficiency in the reconstructed area, and a soft-tissue free flap transfer was required for treatment within an average of 21.5 months of their initial reconstruction. Five rectus abdominis, one rectus femoris, one latissimus dorsi, one tensor fasciae latae myocutaneous, one radial forearm, one medial arm, and one dorsalis pedis flap were used for this purpose. All flaps survived completely. The average follow-up time was 32 months. Significant improvement was achieved in all cases, and no further major surgical procedures were required. Secondary soft-tissue deficits that could not be predicted or prevented during the initial microsurgical reconstruction may be treated successfully by a subsequent free soft-tissue transfer in selected cases.     

Anatomic basis of plantar flap design

Safe planes exist for plantar incisions that minimize the possibility of subcutaneous nerve injury and are therefore useful in flap design. Nerve branch orientation in the plantar subcutaneous tissue is specific and guides dissection so as to avoid producing anesthesia in weight-bearing areas. An extensive proximal plantar subcutaneous plexus exists that permits elevation of plantar flaps in a superficial plane. This is due to the major contribution that the dorsal circulation makes to the skin of the plantar surface. The blood supply to the non-weight-bearing midsole area is not from the medial plantar artery exclusively. This is a watershed area with important lateral plantar artery and dorsalis pedis artery contributions as well. It is not necessary or desirable to base plantar flaps on a myocutaneous or fasciocutaneous supply with its required deep dissection. Local plantar flaps can be designed to include sensation and abundant blood supply without the need for "subfascial" dissection. Subcutaneous sensory plantar flaps designed in accordance with these principles promise a more ideal solution for the treatment of plantar defects.