The pedicled venous flap. Clinical applications

Systematic Review and Meta-Analysis of Unconventional Perfusion Flaps in Clinical Practice

BACKGROUND

Although unconventional perfusion flaps have been in clinical use since 1975, many surgeons are still deterred from using them, because of some reports of high necrosis rates.

METHODS

The authors performed a systematic review and meta-analysis of all articles written in English, French, German, Spanish, and Portuguese on the clinical use of unconventional perfusion flaps and indexed to PubMed from 1975 until July 15, 2015.

RESULTS

A total of 134 studies and 1445 patients were analyzed. The estimated survival rate of unconventional perfusion flaps was 89.5 percent (95 percent CI, 87.3 to 91.3 percent; p < 0.001). Ninety-two percent of unconventional perfusion flaps (95 percent CI, 89.9 to 93.7 percent; p < 0.001) presented complete or nearly complete survival. Most defects mandating unconventional perfusion flap reconstruction were caused by trauma (63.6 percent), especially of the hand and fingers (75.1 percent). The main complication of all types of flaps was a variable degree of necrosis (7.5 percent of all unconventional perfusion flaps presented marginal necrosis; 9.2 percent and 5.5 percent had significant and complete necrosis, respectively). There was a positive correlation between the rate of postoperative infection and the need for a new flap (Pearson coefficient, 0.405; p = 0.001). Flaps used to reconstruct the upper limb showed better survival than those transferred to the head and neck or to the lower limb (p < 0.001).

CONCLUSION

Unconventional perfusion flaps show high survival rates and should probably be used more liberally, particularly in the realm of upper limb reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Influence of the pedicle orientation and length on viability of unipedicled venous island flaps

The use of unipedicled venous flaps has been limited due to their unconventional perfusion patterns and inconsistent survival. Further information regarding the optimal conditions required for unipedicled venous flap coverage is needed to increase flap survival. The purpose of this study was to investigate the effect of the pedicle orientation and length on the viability of unipedicled venous flaps based on a review of our clinical experience. Thirty-one skin and soft tissue hand defects of 29 patients were treated with unipedicled venous flaps. Sixteen defects were treated with proximally pedicled flaps and 15 were treated with distally pedicled flaps. Five of the 16 proximally pedicled flaps and eight of the 15 distally pedicled flaps had pedicle lengths ≥ 5 cm. All proximally pedicled flaps survived, and distally pedicled flaps with pedicle lengths <5 cm (n = 7) also survived. Distally pedicled flaps with pedicle lengths ≥5 cm (n = 8) developed congestion within 1-2 days after surgery, and external bleeding was applied. Four of the eight flaps survived completely, and partial necrosis developed in the other four. The results demonstrate that proximally pedicled venous flaps of the hand can survive regardless of pedicle length. Distally pedicled venous flaps can also survive completely when pedicle length is <5 cm. Distally pedicled venous flaps with pedicle lengths ≥5 cm should be used with caution.

Versatility of venous flap for coverage of proximal and middle phalanges of fingers

Owing to paucity of soft tissue in the fingers, the trauma to fingers can cause exposure of tendons, joints, and bone. Several flaps have been used to cover soft tissue defects of the fingers. From 2007 to 2010, we have operated on 18 male patients with skin defects of dorsal phalanges of fingers. We used reverse distally based venous flap with perivenous tissue to cover the defects. Their mean age was 30.6±8.6 (15 to 40). The etiology in all cases was severe trauma. Ten had defect in dorsal aspect of proximal phalanges and in 8 the defect was in the middle phalanges. One of our patients experienced superficial necrosis at the distal margin of the flap that was successfully treated with local wound care and dressing changes. There was 1 case of venous congestion that resolved itself. There were no postoperative wound infections. There were no serious complications. The venous flap with preservation of perivenous areolar network is a good option for coverage of soft tissue defects of proximal and middle phalanges of fingers.

Clinical applications of venous flaps in the reconstruction of hands and fingers

In recent years, the venous flap has been highly regarded in microsurgical and reconstructive surgeries, especially in the reconstruction of hand and digit injuries. It is easily designed and harvested with good quality. It is thin and pliable, without the need of sacrificing a major artery at the donor site, and has no limitation on the donor site. It can be transferred not only as a pure skin flap, but also as a composite flap including tendons and nerves as well as vein grafts. All these advantages make it an optimal candidate for hand and digit reconstruction when conventional flaps are limited or unavailable. In this article, we review its classifications and the selection of donor sites, update its clinical applications, and summarize its indications for all types of venous flaps in hand and digit reconstruction.

Distally based venous flap: a new technique for the correction of syndactyly without skin graft in adult patients

Skin grafts and local flaps are conventional methods for repairing simple syndactyly. Skin grafts usually leave unsightly appearance and contracture formation. In this study, unipedicled distally based venous flap were raised from third or fourth metacarpal area of the hand for syndactyly treatment. The distally based venous flap was to provide skin coverage to one side of the finger, in order to avoid complications arising from using skin graft. Nine patients' syndactylies (5 simple incomplete and 4 simple complete syndactyly) were treated using this method. The mean follow-up period of the flaps was 14 months, ranging from 12 to 16 months. Mild edema and venous congestion occurred in all flaps. Superficial necrosis involving two flaps did not affect flap survival. All flaps survived completely. In this article, we have described a new surgical technique for the correction of syndactyly in a single surgical procedure that utilizes a distally based venous flap to provide skin coverage without skin graft.

Effects of surgical or chemical delaying procedures on the survival of proximal pedicled venous island flaps: Am experimental study in rats

To increase the survival of proximally pedicled venous island flaps, which are known to be safe only when small, we used surgical and chemical delaying procedures both individually and in combination for 7, 14, and 21 days. Survival was 1% in those flaps designated as controls, in which there was neither surgical nor chemical delay. However, it was 3%, 31%, and 68% at 7, 14, and 21 days, respectively, when surgical delay was used and 16%, 56%, and 86%, at 7, 14, and 21 days, respectively, when chemical delay was used. Survival was 32%, 84%, and 87%, at 7, 14, and 21 days when both chemical and surgical delays were used. We conclude that chemical delay is more effective than surgical delay in increasing survival of proximally pedicled venous island flaps, but the use of combined chemical and surgical delay may reduce the time required for delay.

Reactive oxygen species in experimental ischemic flow-through venous flaps and effects of antioxidants on reactive oxygen species and flap survival

We made an experimental study on rabbit ears using an ischemic flow-through venous flap model to determine the changes in levels of reactive oxygen species (ROS) in venous flaps and effects of exogenous antioxidants on endogenous antioxidant superoxide dismutase (SOD) and ROS indicator malonyldialdehyde (MDA) levels and on flap survival. Mean SOD level significantly decreased and the MDA level significantly increased after the flap elevation according to basal levels of untreated flaps. The mean flap survival rates in the exogenous SOD or glutathione (GSH)-treated groups were significantly increased with respect to the untreated group. The SOD level was increased significantly and the MDA level was decreased significantly in the SOD- or GSH-treated groups relative to the control group after the flap elevation. These results have suggested that ROS may have an important role in ischemic flow-through venous flap pathogenesis and additionally, antioxidants could enhance the rate of flap survival.

Composite Palmaris Longus-Venous Flap for Simultaneous Reconstruction of Extensor Tendon and Dorsal Surface Defects of the Hand???Long-Term Functional Result

Soft tissue loss in the dorsum of the hand resulting from trauma often involves the extensor mechanism due to its thin skin coverage. When such composite skin and extensor tendon defects occur, the wound could be reconstructed with an ipsilateral forearm venous flap with accompanying palmaris longus tendon. Eighteen dorsal finger defects in 12 patients underwent composite venous flap and tendon transfers in the acute stage. We used both Buck-Gram-cko and Tubiana's methods for objective functional assessments. With the former method, the average composite flexion, extension deficit, and total active motion were 207.2 degrees, 39.0 degrees, and 164.7 degrees, respectively. The average score was 12.1 points, which qualified for a "good" result. With Tubiana's method, the average active flexion was 4.9, and the average extension defect was 2.3. The average score was 7.2 point, which also qualified for a "good" result. Thus, a one-stage composite forearm venous flap could be used to reconstruct dorsal skin and tendon defects of the finger with a predictably good functional outcome.

Clinical application of the reversed pedicled venous flap containing perivenous areolar tissue and/or nerve in the hand

A reversed pedicled venous flap containing perivenous areolar tissue and/or nerve was used to cover traumatic skin defects of seven fingers in six patients. The series consisted of six men, ranging in age from 20 to 57 years (average: 39 years). The reconstructed sites were four dorsal skin defects and three volar skin defects of the finger. The flap was designed on the dorsum of the hand, in such a way as to place a vein at the centre of the flap and not to involve the dorsal metacarpal artery. The flap contained a dorsal vein, perivenous areolar tissue and fascia of the interosseous muscle. Cutaneous nerves were present in three of the seven flaps. The pedicle of the flap was dissected distally to the finger web space and the flap was transferred to the skin defect. The size of the flap ranged from 1.4x4.5 cm to 6.0x7.0 cm. The average length of the pedicle was 1.6 cm. Skin grafting was needed at the donor site in one case (flap size: 6.0x7.0 cm), but primary closure was possible in the remaining cases. Postoperatively, the largest flap showed superficial necrosis, although it survived. The remaining flaps survived completely. This suggests that in a large flap the skin should be attached to the pedicle to prevent congestion. The flap can be elevated without reference to the dorsal metacarpal artery at the ulnar side of the dorsum of the hand. The flap is an effective option to reconstruct skin defects of the finger, especially the little finger.

Expansion of venous flaps: an experimental study in rats

In this study, the effects of controlled tissue expansion on the survival of unipedicled venous flaps were investigated in rats. In three groups of Lewis rats, a 3 x 6 cm unipedicled Lateral thoracic venous flap was studied with group 1 as control group (n = 30) without any manipulation, group 2 (n = 30) where an expander was introduced under the flap area but was not expanded and group 3 (n = 30) in which a 40 ml expander was introduced under the flap area and was expanded over a period of 10 days. Observations included gross and histological examination, reverse microangiography, reverse flow resistance and percentage of survival of flaps. Group 3 (expanded) showed more angiogenesis, a better delineation on microangiography, lower reverse flow resistance and higher survival rates as compared to group 2 (non-expanded). In the control group the survival rate of flaps was the poorest and the flaps showed higher rates of reverse flow resistance. Microangiography was not successful in the control group. In a pilot project prior to this experiment microscopic examination of the Lateral thoracic vein in 10 Lewis rats had confirmed the presence of two or three valves in this vein.

Venous flap--its classification and clinical applications

We previously reported pedicled venous flap survival using the rat model, as well as venovenous, arteriovenous, and arterialized flow-through venous flap survival using the rabbit ear model. For this study, we utilized these flaps clinically. Five of seven pedicled venous flaps survived, displaying superficial necrosis. The others became partially necrotic; they were transferred after dissection of a long pedicle vein. Eight of nine venovenous flow-through venous flaps survived; six displayed superficial necrosis. The nonsurviving flap became completely necrotic, possibly because only one donor vein and one recipient vein were used. Six of 10 arteriovenous flow-through venous flaps survived. The remaining four became partially necrotic, possibly because only one vein was anastomosed for outflow. The arterialized flow-through venous flap survived. The pedicled venous and venovenous groups studied seem likely to survive despite superficial necrosis. However, the draining vein should not be dissected more than 5 cm, and many draining veins should be anastomosed with recipient vessels.

"Plasmatic imbibition" in the rat musculocutaneous pedicled venous flap: enzymatic proof using horseradish peroxidase

To determine the reason for survival of a pedicled venous flap in which only a draining vein is preserved, it is important to clarify what kind of blood flow is present in the preserved draining vein. Pedicled venous flaps were prepared on the dorsum of the rat and histologically evaluated using horseradish peroxidase (HRP). HRP was applied between the flap and recipient bed in one group. In the other group, HRP was injected into the femoral vein after the flap was turned over (to prevent contact with the recipient bed). The flaps in these HRP-treated groups were compared with untreated control groups. HRP applied between the flap and recipient bed was imbibed into the flap and subsequently transferred into the preserved draining vein. HRP that was injected into the femoral vein was also found in the draining vein of the flap. These results suggest that (1) plasmatic imbibition occurs in pedicled venous flaps; and (2) antegrade and retrograde blood flow are present in the draining vein.