A comparison of arterial and venous flaps

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.

Venous flaps for coverage of traumatic soft tissue defects of the hand: a systematic review

A PRISMA-guided systematic review was performed of all published cases that detail the use of venous flaps for soft tissue reconstruction of the hand following trauma. Outcome measures examined included flap survival rates, venous congestion, and return to theatre. Database searches were performed on Medline, Embase, AHMED, CINAHL. A total of 381 articles were identified. Data were extracted from 45 articles that met inclusion criteria. A total of 756 flaps were described and their data analysed. A total of 75% of flaps were arterialized and 25% were pure venous flaps. There was no difference in survival rate for arterialized or pure venous flaps. Unplanned return to theatre occurred in 5.3% due to flap compromise or necrosis. Early venous congestion was present in 60% of cases. Total early failure requiring re-operation occurred in 19 flaps (2.5%) of cases. Venous flaps offer a versatile and well-tolerated reconstructive option. Early venous congestion is common, but can be managed non-operatively.

LEVEL OF EVIDENCE

II.

Optimization of an Arterialized Venous Fasciocutaneous Flap in the Abdomen of the Rat

BACKGROUND

Although numerous experimental models of arterialized venous flaps (AVFs) have been proposed, no single model has gained widespread acceptance. The main aim of this work was to evaluate the survival area of AVFs produced with different vascular constructs in the abdomen of the rat.

METHODS

Fifty-three male rats were divided into 4 groups. In group I (n = 12), a 5-cm-long and 3-cm-wide conventional epigastric flap was raised on the left side of the abdomen. This flap was pedicled on the superficial caudal epigastric vessels caudally and on the lateral thoracic vein cranially. In groups II, III, and IV, a similar flap was raised, but the superficial epigastric artery was ligated. In these groups, AVFs were created using the following arterial venous anastomosis at the caudal end of the flap: group II (n = 13) a 1-mm-long side-to-side anastomosis was performed between the femoral artery and vein laterally to the ending of the superficial caudal epigastric vein. In group III (n = 14), in addition to the procedure described for group II, the femoral vein was ligated medially. Finally, in group IV (n = 14), the superficial caudal epigastric vein was cut from the femoral vein with a 1-mm-long ellipse of adjacent tissue, and an end-to-side arterial venous anastomosis was established between it and the femoral artery.

RESULTS

Seven days postoperatively, the percentage of flap survival was 98.89 ± 1.69, 68.84 ± 7.36, 63.84 ± 10.38, 76.86 ± 13.67 in groups I-IV, respectively.

CONCLUSION

An optimized AVF can be produced using the vascular architecture described for group IV.

Flap survival after previous vascular pedicle division and preexisting scar formation at the pedicle site: an experimental study

BACKGROUND

We conducted an experimental study to investigate if it would be possible to re-elevate a flap at a standard flap site if its vascular pedicle was mutilated previously and there was a preexisting scar formation at the pedicle site.

MATERIALS AND METHODS

Thirty-five male Sprague-Dawley rats were divided into 3 groups. In the control group (n = 5), animals received a procedure in which unilateral axial pattern abdominal flap was elevated, and then sutured to its original place. The remaining 2 groups underwent 2-stage procedures. In the first stage, scar tissue was created with either a skin incision (group 2, n = 15) or excision (group 3, n = 15) at the prospective pedicle site of the abdominal flap. In the second stage, abdominal flap was raised in 5 rats as a scar-pedicled flap at day 7, day 21, and day 42. Flaps were sutured in their places. Seven days later, flap survival was evaluated.

RESULTS

Control flaps had complete survival (day 7, 95.5%; day 21, 94.8%; and day 42, 94.5%). Group 2 and group 3 flaps raised on day 7 (group 2, 65.4%; group 3, 63.9%) and on day 21 (group 2, 65.7%; group 3, 66.7%) showed decreased survival compared to control group flaps (P < 0.05). On day 42, group 1 flaps had better survival when compared to group 2 flaps (82.6% vs 70.0%, P < 0.05). Group 1 flaps showed progressive vascular network formation as evidenced by contrast medium first in the proximal two thirds of the flaps on day 7, and later via visualization of the axial pattern vascular tree on day 42. In group 3, approximately half of the flap was filled with barium contrast and no single pedicle was identified on day 42.

CONCLUSIONS

Preexisting scar tissue and pedicle division in the pedicle site of a standard flap diminished dimensions of surviving flap when compared to control flaps. Incision-scar-pedicled flaps achieved better survival compared to excision-group flaps, particularly in the late postoperative period. The study findings showed that it may be possible to raise a flap from previously mutilated site secondary to scar formation and pedicle injury.

Free vascularised iliac bone graft for recalcitrant avascular nonunion of the scaphoid

We report the use of a free vascularised iliac bone graft in the treatment of 21 patients (19 men and 2 women) with an avascular nonunion of the scaphoid in which conventional bone grafting had previously failed. The mean age of the patients was 32 years (23 to 46) and the dominant wrist was affected in 14. The mean interval from fracture to the vascularised bone grafting was 39 months (9 to 62). Pre-operative MRI showed no contrast enhancement in the proximal fragment in any patient. Fracture union was assessed radiologically or with CT scans if the radiological appearances were inconclusive.

At a mean follow-up of 5.6 years (2 to 11) union was obtained in 16 patients. The remaining five patients with a persistent nonunion continued to experience pain, reduced grip strength and limited range of wrist movement. In the successfully treated patients the grip strength and range of movement did not recover to match the uninjured side.

Prevention of progressive carpal collapse, the absence of donor site morbidity, good subjective results and pain relief, justifies this procedure in the treatment of recalcitrant nonunion of the scaphoid.

Free arterialised venous forearm flaps for intraoral reconstruction

In 29 patients, the intraoral defect after excision of an oral squamous cell carcinoma was repaired with an arterialised venous forearm flap. In all cases, a flap of skin and fat with a superficial vein passing through it was raised from the flexor surface of the right forearm. After the flap had been sutured into the intraoral defect, the original distal end of the vein was anastomosed to an artery and the original proximal end to a vein. Fifteen (52%) of the flaps survived completely, six (21%) had superficial epithelial loss or some marginal necrosis and eight (27%) became completely necrotic. Areas of partial loss developed slowly and formed stable granulation tissue. The flap donor sites were either closed primarily (n = 20) or were covered with a split thickness skin graft (n = 9). There were no functional problems of the donor forearms. These results contrast with the high success rates achieved with orthodox free radial forearm flaps. Further research into venous flaps is essential.

Arterialized tendocutaneous venous flap for dorsal finger reconstruction

We describe three cases of combined loss of skin and tendon on the dorsum of the finger that were reconstructed with venous flaps. The technique is feasible and offers a good treatment modality for the small but complex defect on the dorsum of the finger by a one-stage operation.

Observations on experimental flow-through venous flaps

The aim of this work was to compare the survival of an arteriovenous island flap with the survival of an island flap with a flow-through venous supply. Our experimental studies were performed on 95 Wistar rats randomised into six groups: Group 1: Indian ink injection of flow-through venous flaps with capillary network; Group 2: control group deprived of vascularisation; Group 3: control group with arteriovenous supply; Group 4: flow-through venous flaps of group 1; Group 5: epigastric flow-through venous flaps with a main venous trunk; Group 6: histological examination of flow-through venous flaps. The survival of flaps was monitored by direct examination, histological examination, capillaroscopy, and laser Doppler. Three out of 50 flow-through venous flaps survived. There was a statistically significant difference in the delay of clinical necrosis between the composite non vascularised free grafts (2.8 +/- 1.2 days) and the flow-through venous flaps (4.1 +/- 1.3 to 4.9 +/- 1.1 days depending on the type of flap). A 20% decreased venous blood flow was observed in the flow-through venous flaps.