The concept of fillet flaps: classification, indications, and analysis of their clinical value

Tissue of amputated or nonsalvageable limbs may be used for reconstruction of complex defects resulting from tumor and trauma. This is the "spare parts" concept.By definition, fillet flaps are axial-pattern flaps that can function as composite-tissue transfers. They can be used as pedicled or free flaps and are a beneficial reconstruction strategy for major defects, provided there is tissue available adjacent to these defects.From 1988 to 1999, 104 fillet flap procedures were performed on 94 patients (50 pedicled finger and toe fillets, 36 pedicled limb fillets, and 18 free microsurgical fillet flaps).Nineteen pedicled finger fillets were used for defects of the dorsum or volar aspect of the hand, and 14 digital defects and 11 defects of the forefoot were covered with pedicled fillets from adjacent toes and fingers. The average size of the defects was 23 cm2. Fourteen fingers were salvaged. Eleven ray amputations, two extended procedures for coverage of the hand, and nine forefoot amputations were prevented. In four cases, a partial or total necrosis of a fillet flap occurred (one patient with diabetic vascular disease, one with Dupuytren's contracture, and two with high-voltage electrical injuries).Thirty-six pedicled limb fillet flaps were used in 35 cases. In 12 cases, salvage of above-knee or below-knee amputated stumps was achieved with a plantar neurovascular island pedicled flap. In seven other cases, sacral, pelvic, groin, hip, abdominal wall, or lumbar defects were reconstructed with fillet-of-thigh or entire-limb fillet flaps. In five cases, defects of shoulder, head, neck, and thoracic wall were covered with upper-arm fillet flaps. In nine cases, defects of the forefoot were covered by adjacent dorsal or plantar fillet flaps. In two other cases, defects of the upper arm or the proximal forearm were reconstructed with a forearm fillet. The average size of these defects was 512 cm2. Thirteen major joints were salvaged, three stumps were lengthened, and nine foot or forefoot amputations were prevented. One partial flap necrosis occurred in a patient with a fillet-of-sole flap. In another case, wound infection required revision and above-knee amputation with removal of the flap.Nine free plantar fillet flaps were performed-five for coverage of amputation stumps and four for sacral pressure sores. Seven free forearm fillet flaps, one free flap of forearm and hand, and one forearm and distal upper-arm fillet flap were performed for defect coverage of the shoulder and neck area. The average size of these defects was 432 cm2. Four knee joints were salvaged and one above-knee stump was lengthened. No flap necrosis was observed. One patient died of acute respiratory distress syndrome 6 days after surgery.Major complications were predominantly encountered in small finger and toe fillet flaps. Overall complication rate, including wound dehiscence and secondary grafting, was 18 percent. This complication rate seems acceptable. Major complications such as flap loss, flap revision, or severe infection occurred in only 7.5 percent of cases. The majority of our cases resulted from severe trauma with infected and necrotic soft tissues, disseminated tumor disease, or ulcers in elderly, multimorbid patients.On the basis of these data, a classification was developed that facilitates multicenter comparison of procedures and their clinical success. Fillet flaps facilitate reconstruction in difficult and complex cases. The spare part concept should be integrated into each trauma algorithm to avoid additional donor-site morbidity and facilitate stump-length preservation or limb salvage.     

The lateral forearm flap as a modification of the lateral arm flap: vascular anatomy and clinical implications

The forearm extension of the lateral arm flap was introduced on the basis of the vascular territory of the posterior radial collateral artery extending beyond the elbow into the forearm. However, there is controversy as to whether the posterior radial collateral artery extends as a single trunk below the elbow or if it terminates more proximally with only a rich vascular plexus extending beyond the elbow. The purpose of this study was to revisit the artery's anatomy in the region of the elbow and to study its distribution in the forearm. Using latex and barium-gelatin injections of the posterior radial collateral artery in ten cadaveric upper limbs, it was observed that terminal branching of the artery occurred 4.5 cm proximal to the lateral epicondyle of the humerus. Distal to the epicondyle, the terminal branches of the posterior radial collateral artery were seen to fan out as finely arborized branches supplying the lateral forearm skin. No single, constant vascular trunk to the forearm skin could be identified. Furthermore, in its distribution toward the periphery, the terminal branches of the posterior radial collateral artery took an increasingly superficial course. Proximal to the epicondyle, the vessels lay deep within the subcutaneous fat, whereas distal to the epicondyle, they were very close to skin. These findings suggest that lateral forearm skin cannot be islanded without risk of vascular disruption and that the distally sited flap should include skin proximal to the epicondyle for safety.     

Osteoradionecrosis of the olecranon: treatment by radial forearm flap

Osteoradionecrosis of the olecranon is an unusual pathologic entity, treated best by debridement and wound closure using vascularized tissue. Local skin is often unavailable for flap design and transposition. The radial forearm flap can be isolated on a proximal vascular pedicle and transposed to cover the wound. In the case presented, healing was brisk and complete, allowing early elbow mobilization. Although the donor site is not easily concealed, no functional impairment results from flap elevation and all full-thickness wounds are confined to the involved extremity.     

Traction avulsion amputation of the major upper limb: a proposed new classification, guidelines for acute management, and strategies for secondary reconstruction.

Major replantation of a traction avulsion amputation is undertaken with the goal of not only the reestablishment of circulation, but also functional outcome. This type of amputation is characterized by different levels of soft-tissue divisions involving crushing, traction, and avulsion injuries to various structures. Between 1985 and 1998, 27 cases were referred for secondary reconstruction following amputation of the upper extremity involving both arm and forearm. Replantation was performed by at least 12 qualified plastic surgeons using different approaches and management, resulting in different outcomes. Initial replantation management significantly affects the later reconstruction. For comparing studies and prognostic implications, the authors propose a new classification according to the level of injury to muscles and innervated nerves: type I, amputation at or close to the musculotendinous aponeurosis with muscles remaining essentially intact; type II, amputation within the muscle bellies but with the proximal muscles still innervated; type III, amputation involving the motor nerve or neuromuscular junction, thereby causing total loss of muscle function; and type IV, amputation through the joint; i.e., disarticulation of the elbow or shoulder joint. Some patients required further reconstruction for functional restoration after replantation, but some did not. Through this retrospective study based on the proposed classification system, prospective guidelines for the management of different types of traction avulsion amputation are provided, including the value of replantation, length of bone shortening, primary or delayed muscle or nerve repair, necessity of fasciotomy, timing for using free tissue transfer for wound coverage, and the role of functioning free muscle transplantation for late reconstruction. The final functional outcome can also be anticipated prospectively through this classification system.     

Use of an adipofascial flap based on the proximal perforators of the ulnar artery to correct contracture of elbow burn scars: an anatomic and clinical approach.

Different techniques can be used to repair contracture of burn scars on the elbow, including local or distant pedicle flaps, muscle or myocutaneous flaps, free flaps, and tissue expanders. Among these, a pedicled adipofascial flap based on the most proximal two to four perforators of the ulnar artery (located 1 to 5 cm from the origin of the artery) can be anastomosed to form a sort of axially patterned blood supply within the fascia and subcutaneous fat. Therefore, no major vessel in the forearm need ever be severed. In addition, use of this type of flap preserves muscle function. The pedicled adipofascial flap described in this article allows for early rehabilitation because the flap is thin and pliable. Additional advantages are the easy and quick dissection and completion of the procedure in one stage. A detailed anatomic dissection of the flap was performed on 16 upper extremities from fresh cadavers; an injection study was also performed to determine the location and dimensions of the pedicle flap and its area of reach around the elbow. In the past 3 years, 14 flaps were used in 13 patients to repair elbow defects after release of burn scar contractures. Flap dimensions ranged from 4 x 7 cm to 6 x 14 cm (mean flap size, 74 cm). The results were very satisfactory.     

Primary closure of radial forearm flap donor defects with a bilobed flap based on the fasciocutaneous perforator of the ulnar artery

To primarily repair a series of radial forearm flap donor defects, a total of 10 bilobed flaps based on the fasciocutaneous perforator of the ulnar artery were designed at the Chang Gung Memorial Hospital in Kaohsiung in the period from January of 2002 to January of 2003. All patients were male, with ages ranging from 36 to 67 years. The forearm donor defects ranged in size from 5 x 6 cm to 8 x 8 cm, with the average defect being 47 cm. One to three sizable perforators from the ulnar artery were consistently observed in the distal forearm and were most frequently located 8 cm proximal to the pisiform, which could be used as a pivot point for the bilobed flap. The bilobed flap consisted of two lobes, one large lobe and one small lobe. With elevation and rotation of the bilobed flap, the large lobe of the flap was used to repair the radial forearm donor defect and the small lobe was used to close the resultant defect from the large lobe. All bilobed flaps survived completely, without major complications, and no skin grafting was necessary. Compared with conventional methods for reconstruction of radial forearm donor defects, such as split-thickness skin grafting, the major advantage of this technique is its ability to reconstruct the donor defect with adjacent tissue in a one-stage operation. Forearm donor-site morbidity can be minimized with earlier hand motion, and better cosmetic results can be obtained. Furthermore, because a skin graft is not used, no additional donor area is necessary. However, this flap is suitable for closure of only small or medium-size donor defects. A lengthy postoperative scar is its major disadvantage.     

Free-flap salvage of a traumatic below-knee amputation

A traumatic below-knee amputation with extensive soft-tissue loss and tibial bone exposure was salvaged by employing microsurgical free-tissue transfer to obtain stable soft-tissue coverage. The free flap covering the bony stump and knee function have done well with over 1 year follow-up.     

The radial forearm skin graft-fascial flap

The radial forearm flap has become a versatile flap for upper extremity reconstruction. The use of the forearm flap for hand reconstruction in the patient with previously burned forearms has not been widely appreciated. In those patients whose forearms have been previously split-thickness skin-grafted on fascia, we have employed the reverse radial forearm flap as a skin graft-fascial flap for hand reconstruction and have obtained excellent functional results. Three patients at various intervals postburn are presented to demonstrate use of this flap for wrist contracture release, coverage of arthroplasties, first web space contracture release, and acute salvage of phalanges and tendons. Assessment of the hand's vascular anatomy and careful treatment of the donor area have contributed to no added morbidity and an excellent aesthetic result at the donor site.     

Kinetic chain of overarm throwing in terms of joint rotations revealed by induced acceleration analysis

This study investigated how baseball players generate large angular velocity at each joint by coordinating the joint torque and velocity-dependent torque during overarm throwing. Using a four-segment model (i.e., trunk, upper arm, forearm, and hand) that has 13 degrees of freedom, we conducted the induced acceleration analysis to determine the accelerations induced by these torques by multiplying the inverse of the system inertia matrix to the torque vectors. We found that the proximal joint motions (i.e., trunk forward motion, trunk leftward rotation, and shoulder internal rotation) were mainly accelerated by the joint torques at their own joints, whereas the distal joint motions (i.e., elbow extension and wrist flexion) were mainly accelerated by the velocity-dependent torques. We further examined which segment motion is the source of the velocity-dependent torque acting on the elbow and wrist accelerations. The results showed that the angular velocities of the trunk and upper arm produced the velocity-dependent torque for initial elbow extension acceleration. As a result, the elbow joint angular velocity increased, and concurrently, the forearm angular velocity relative to the ground also increased. The forearm angular velocity subsequently accelerated the elbow extension and wrist flexion. It also accelerated the shoulder internal rotation during the short period around the ball-release time. These results indicate that baseball players accelerate the distal elbow and wrist joint rotations by utilizing the velocity-dependent torque that is originally produced by the proximal trunk and shoulder joint torques in the early phase.     

Reconstruction of short lower leg stumps with the osteomusculocutaneous latissimus dorsi-rib flap

To avoid a more proximal amputation at the distal part of the thigh, and when the knee joint is preserved, it is possible to lengthen short lower leg stumps. The authors report five cases in which the latissimus dorsi-rib flap was used to achieve a satisfactory functional prosthetic result. The bone segment is long enough to both lengthen the stump and allow its extremities to be firmly fixed to the tibia. Depending on the remaining tibia length, one or two ribs were included in the flap. The procedure allowed achievement of a 5-cm to 9-cm lengthening of the tibia. Bone healing time was 5 to 6 months and allowed prosthetic rehabilitation and ambulating 5 to 7 months after surgery. Final range of motion of the knee joint is compatible with normal ambulating, and the prosthesis is well tolerated. This procedure, which provides a large amount of skin, muscle, and bone, is very effective for reconstruction of short lower leg stumps.     

Directional sensitivity along the upper limb in humans

The capacity of four neurologically healthy young adults to distinguish opposing directions of cutaneous motion was determined at five different sites along the proximal-distal axis of the upper limb. Constant-velocity brushing stimuli (ranging from 0.5 to 32.0 cm/sec) were delivered through an aperture in a Teflon plate that was securely positioned in light contact with the skin. In one series of experiments, directional sensitivity in d' units was assessed at each site, using an aperture length of 0.75 cm. In a second series of experiments, the aperture length required to obtain the same criterion level of directional sensitivity at each site was determined. To attain the sensitivity reached at distal sites, a proximal stimulus had to traverse a longer chord of skin. Specifically, chords 5.9 times longer on average (range = 5.4-6.2) were required on the proximal forearm than on the index finger pad. This finding suggests that relative directional sensitivity increases sixfold from the proximal forearm to the finger pad. Moreover, relative directional sensitivity on the shoulder was comparable to that observed on the proximal forearm for two of the subjects, and approximately one-half that observed on the proximal forearm for the other two subjects. In addition to such a prominent spatial gradient in relative directional sensitivity, the velocity of stimulus motion at which directional sensitivity was highest increased systematically as the test site was shifted from the finger pad to the proximal forearm. Specifically, the optimal velocity on the finger pad varied among subjects from 1.5 to 9.4 cm/sec (mean = 5.4 cm/sec), and on the proximal forearm from 11.5 to 31.2 cm/sec (mean = 18.6 cm/sec). The optimal velocity on the shoulder was not significantly different from that observed on the proximal forearm. The results suggest that effective and informed clinical testing of patients' capacity to distinguish opposing directions of motion on cutaneous regions that differ in peripheral innervation density requires appreciation of the sensitivities of different skin regions, as well as the unique velocity dependency of direction discrimination at each skin site.     

Free-flap free flap

We present a patient who sustained bilateral below-knee amputations that were treated with skin grafts as initial coverage. A latissimus dorsi free flap was later used as definitive coverage of one stump. Then at a subsequent operation a portion of the same latissimus dorsi free flap was reharvested, again as a free flap, and transplanted to cover the contralateral stump. Thus one latissimus dorsi free flap was used twice as a free flap (free-flap free flap) to cover bilateral amputation stumps in sequential operations.     

Distally based dorsal forearm fasciosubcutaneous flap

Use of a local flap is often required for the reconstruction of a skin defect on the dorsum of the hand. For this purpose, a distally based dorsal forearm fasciosubcutaneous flap based on the perforators of the posterior interosseous artery was developed. From 1997 until 2002, this flap was used to reconstruct skin defects on the dorsum of the hand in nine patients at Chonnam National University Medical School. The sizes of these flaps ranged from 10 to 14 cm in length and from 5 to 7 cm in width. The flaps survived in all patients. Marginal loss over the distal edge of the flap was noted in one patient. Three flaps that developed minimal skin-graft loss were treated successfully with a subsequent split-thickness skin graft. The long-term follow-up showed good flap durability and elasticity. The distally based dorsal forearm fasciosubcutaneous flap is a convenient and reliable alternative for reconstructing skin defects of the dorsum of the hand involving vital structure exposure. It obviates the need for more complicated and time-consuming procedures.     

A fasciocutaneous flap for vaginal and perineal reconstruction

A skin and fascia flap from the medial thigh is proposed for vaginal and perineal reconstruction. Dissection, vascular injection, and radiographs of 20 fresh cadaver limbs uniformly demonstrated the presence of a communicating suprafascial vascular plexus in the medial thigh. Three to four nonaxial vessels were consistently found to enter the proximal plexus from within 5 cm of the perineum. Preservation of these vessels permitted reliable elevation of a 9 X 20 cm fasciocutaneous flap without using the gracilis muscle as a vascular carrier. Fifteen flaps in 13 patients were used for vaginal replacement and coverage of vulvectomy, groin, and ischial defects. Depending on the magnitude of the defect, simultaneous and independent elevation of the gracilis muscle provided additional vascularized coverage as needed. Our experience indicates that the medial thigh fasciocutaneous flap is a durable, less bulky, and potentially sensate alternative to the gracilis musculocutaneous flap for vaginal and perineal reconstruction.     

四种灵长类肘关节的生物力学研究

对懒猴、猕猴、叶猴和长臂猿的肘关节形态与功能和前臂伸、屈肌肌肉电生理的研究结果表明,随着上肢运动功能的加强,肘关节的灵活性亦相应增大。猕猴各肌的肌电活动相对较弱,肘关节的结构明显不同于其它3个种,表现出对四足型运动和维持关节稳定性的适应特点。叶猴肘关节的形态结构和前臂各肌的肌电活动类似于长臂猿,表现出与臂摆荡有关的活动特点。对前臂伸、屈肌有关指数的判别分析表明,与骨骼相比,4个种的前臂各肌的形态差异明显较大。肱肌的近侧起点指数。肱桡肌的止点指数和肱三头肌内侧头的起点指数可作为4个种的鉴定特征。     

Correction of first web space deficiency in congenital deformities of the hand with the pseudokite flap

The authors describe a new flap to enlarge or create a first web in patients with congenital deficiencies of the hand. This lozenge-shaped flap is harvested from the dorsoradial aspect of the index finger based on a narrow proximal skin bridge protecting its axial vascularization. A dorsal skin graft of the donor site is avoided by closure using a rhomboid flap. Procedures in 16 patients were performed and reviewed; the only complication was insertion of a small split-thickness graft in five patients to avoid tension at the metacarpophalangeal joint level. The flap lengthened the web fold an average of 3.2 cm without "pseudolengthening" the thumb.     

An Investigation of the Locomotor Function of Therian Forearm Pronation Provides Renewed Support for an Arboreal,Chameleon-like Evolutionary Stage

Although investigations of forelimb characteristics are central to therian evolutionary studies, the functional origins of forearm pronation are neglected. However, recent research based on bipedal manipulations strongly suggests that proximal radioulnar joint mobility is highly conserved in tetrapods. This new information calls for a replication of previously published physical simulations of forearm bone movements, to investigate whether active therian pronation/supination evolved from the plesiomorphic mechanism via which locomotor-induced torsion is passively alleviated during forelimb retraction. Preliminary results using representative extant and extinct tetrapod forelimb elements are supportive, and also offer insight into why another overlooked forearm trait, osteological full pronation (mechanically aligned elbow and wrist/finger joints), evolved only in therians and chameleons. During forelimb retraction in tetrapods with unfused radii/ulnae, the radius unexpectedly remains fixed in place as a functional complex with the firmly planted manus/carpus, which the ulnar complex (ulna/humerus) displaces relative to. Therefore, the highly conserved functional morphology of the tetrapod forearm indicates that enhanced therian manual dexterity, which emphasizes isolated radial movements bipedally, was preceded by the locomotor evolution of ulnar supination relative to the radius quadrupedally. This counterintuitive information indicates that the traditional hypothesis, that therian pronation/supination evolved arboreally to amplify radial mobility, requires modification. The authors propose that proximal long-axis rotations of the therian ulnar complex co-evolved with osteological full pronation during a period of arboreal, chameleon-like locomotion, to continue allowing torsion at a reinforced proximal radioulnar joint. These adaptations were later or simultaneously co-opted for object manipulation using active radioulnar pronation/supination.     

The dorsal reverse adipofascial flap for fingertip reconstruction

Nine patients who presented with fingertip amputations were treated with the dorsal reverse adipofascial flap. The mean age of the patients was 41.3 years and the mean follow-up was 18 months. The flap described here was used only for amputations at the level of the nail fold, from approximately the lunula to the proximal nail matrix. This flap is based on the dorsal arterial branches that originate from the volar digital arteries just distal to the distal interphalangeal joint. The flap uses only the adipofascial tissue over the middle phalanx of the injured finger; it is turned over to cover the fingertip defect and then covered with a split-thickness skin graft. All flaps survived completely, and the patients continue to use their fingertips as before the amputation injury. This one-step operation is easily performed (even in the emergency department), makes no use of the adjacent digits, and provides a pleasing and stable cover for the fingertips.     

Salvage of functional elbow range of motion in complex open injuries using a sensate transposition lateral arm flap

Complex open posterior elbow injuries pose three principal challenges to the reconstructive surgeon. First, the surgeon must provide stable soft-tissue closure over the joint/skeletal reconstruction. Second, the coverage must be thin and supple and promote the free gliding of the underlying structures. Finally, secondary and tertiary procedures must be anticipated beneath the flap, because a stiff, scarred, and adherent flap will only compromise these procedures. The results of 10 consecutive fasciocutaneous transposition lateral arm flaps for coverage of posterior elbow wounds are reported. This flap provides coverage that is thin and supple and that allows subsequent elevation for secondary procedures. Functionally, these flaps allowed for the development of an average arc of motion of 20 to 114 degrees and an average pronation-supination motion of 119 degrees.     

Leg length preservation with pedicled fillet of foot flaps after traumatic amputations

Six patients with insufficient soft-tissue coverage after lower limb trauma were treated with pedicled fillet of foot flaps to achieve primary stump closure and to preserve leg length. The flaps used were all based on either the posterior tibial neurovascular pedicle, the anterior tibial neurovascular pedicle, or both. Five flaps survived; one patient required conversion of a through-knee to an above-knee amputation and debridement of the flap because of venous thrombosis of the pedicle. In three of the cases, a functional knee joint was preserved. The patients ranged in age from 21 to 54 years, the mean hospital stay was 55.5 days (range, 28 to 76 days), and the mean follow-up time was 14.5 months. Despite an average of 4.3 procedures from initial admission to first discharge and an average of 2.0 postamputation procedures to achieve primary stump healing, all patients have achieved independent mobility with their prosthesis. The advantages of preserving leg length and, where possible, preserving a functional knee joint compensate for repeated procedures on these patients. When planned well, a pedicled fillet of foot flap therefore achieves the aims of amputation, namely, providing primary healing of a sensate, durable, cylindrical stump that is pain-free and preserves maximal leg length. This is achieved with no donor-site morbidity and with no need for microvascular reconstruction.