Transfer of a pedicled venous flap containing perivenous areolar tissue and nerve: an experimental study

Unconventional Perfusion Flaps in the Experimental Setting: A Systematic Review and Meta-Analysis

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Background:

Unconventional perfusion flaps offer multiple potential advantages compared with traditional flaps. Although there are numerous experimental articles on unconventional perfusion flaps, the multiple animal species involved, the myriad vascular constructions used, and the frequently conflicting data reported make synthesis of this information challenging. The main aim of this study was to perform a systematic review and meta-analysis of the literature on the experimental use of unconventional perfusion flaps, to identify the best experimental models proposed and to estimate their global survival rate.

Methods:

The authors performed a systematic review and meta-analysis of all articles written in English, French, Italian, Spanish, and Portuguese on the experimental use of unconventional perfusion flaps and indexed to PubMed from 1981 until February 1, 2017.

Results:

A total of 68 studies were found, corresponding to 86 optimized experimental models and 1073 unconventional perfusion flaps. The overall unconventional perfusion flap survival rate was 90.8 percent (95 percent CI, 86.9 to 93.6 percent; p < 0.001). The estimated proportion of experimental unconventional perfusion flaps presenting complete survival or nearly complete survival was 74.4 percent (95 percent CI, 62.1 to 83.7 percent; p < 0.001). The most commonly reported animal species in the literature were the rabbit (57.1 percent), the rat (26.4 percent), and the dog (14.3 percent). No significant differences were found in survival rates among these species, or among the diverse vascular patterns used.

Conclusion:

These data do not differ significantly from those reported regarding the use of unconventional perfusion flaps in human medicine, suggesting that rabbit, rat, and canine experimental unconventional perfusion flap models may adequately mimic the clinical application of unconventional perfusion flaps.

Delay of the reverse pedicled venous island flap: clinical applications

In patients with hand or foot injuries, the delay procedure of the reverse pedicled venous flap was applied, including the loose areolar tissue around the pedicle vein. As preliminary clinical observations, five patients were treated with delay and the results compared with those of four patients without delay. The delay procedures were two types: type 1 was circumferential incision with ligature of the proximal vein, and type 2 was a bipedicled flap without ligature of the pedicle vein. Two weeks later, the flap was transferred to the defect. In the patients treated without delay, the maximum limit of the perfectly survived flap sizes was 4.0 × 2.0 cm. However, in the patients treated with delay, the perfectly survived sizes were 5.0 × 3.0 cm and 10 × 4.0 cm in type 1 delay and 12 × 5.0 cm in type 2 delay. The delay procedure appeared to stabilise the reverse pedicled venous flap and to expand its clinical applications.

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.

Pre-arterialisation of the arterialised venous flap: an experimental study in the rat

Arteriovenous fistulae cause haemodynamic and morphological changes to the local venous channels. We have used the concept of preformed arteriovenous fistulae to study the viability improvement of arterialised venous flaps. Five groups of flaps were created using the abdominal skin of the Wistar rat (n= 10 in each group) with a silastic sheet implanted underneath. Group 1 (control) contained a flap without a vascular supply, group 2 (venous perfusion flap) contained a single pedicled skeletonised vein and a draining vein, and group 3 (arterialised venous flap) contained an arteriovenous shunt proximal to the single pedicled skeletonised vein and a draining vein; in group 4 (7 day pre-arterialised flap) the arteriovenous shunt was performed 7 days before the flap was raised in the same procedure as group 3, and in group 5 (14 day pre-arterialised flap) the arteriovenous shunt was performed 14 days before the flap was raised. The surviving surface areas of the flaps in each group, assessed 7 days after raising, were 0%, 22.21%, 54.32%, 62.21% and 97.47%, respectively. There was a statistically significant difference in survival between venous perfusion flaps and arterialised venous flaps (P= 0.05). Only the 14 day pre-arterialised flaps had a statistically significantly larger area of survival than arterialised venous flaps (P= 0.05). Microangioarchitecture of the pre-arterialised group, studied by the microvascular corrosion-cast technique combined with scanning electron microscopy and transmission electron microscopy, revealed dilatation of veins, numerous small neo-vessels and a decrease in or total absence of functioning valves. We conclude that 14-day pre-arterialisation in the rat model improved the survival of arterialised venous flaps by increasing collateral pathways for arterialised blood flow through the flap.

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.