To Establish a Predictive Model for Maximum Propeller Fasciocutaneous Flap Dimensions Based on Perforator Characteristics for Leg Defects.

Abstract

Background
Propeller flaps have gained more importance recently and these flaps are being increasingly used for reconstruction of soft tissue defects of different parts of the body, and surgical technique has been refined and well described by several authors. This study is an attempt to define a safe limit of perforator propeller flaps in lower limb reconstruction and feasibility as an alternative to more complex free flap procedures.
Objective
To establish dimensions of propeller fascio-cutaneous flap which can be safely harvested, according to the size and location of perforator in leg and according to dimensions and location of defects, in patients with leg defects.
Method
Patients presenting to Krishna institute of medical sciences between Jan 2022- June 2023, with lower leg defect from knee to heel, where a flap cover was necessary for wound healing were selected for this study. They underwent flap surgery with flap based either on posterior tibial or anterior tibial or peroneal artery perforators according to location of defect and preop marking of the selected perforator. All post operative patients were followed up for results and any complications were recorded and analysed.
Results
30 patients included in study as per inclusion criteria. Mean age was 44.6 yrs. 22 (73.33%) patients were males and remaining 8 (26.66%) patients were females. 16(53.33%) patients were done Posterior Tibial Artery (PTA) perforator flap; 4(13.33%) patients were done Peroneal Artery (PA) perforator flap and 10(33.33%) patients were done Anterior Tibial Artery (ATA) perforator flaps to cover the defects. Average area of flap raised from ATA based flaps was 71 cm2, from PA based perforators was 75.2 cm2 and from PTA based perforators was 60.1cm2. Average length of flap harvested - 13.2 cm and average length of leg was 37.7 cm. Overall mean operative time - 140 min. 15 (50%) patients had postoperative complications. 8 (26.7%) patients had Distal Necrosis (DN)/ Partial Necrosis (PN); out of these three patients had 2cm. distal necrosis, two had 1cm distal necrosis and three had 4cm distal necrosis. Nine (30%) patients had postoperative flap congestion (C). Four (13.33%) patients had Complete Necrosis (CN) of flap. the average length of flap which can safely be harvested on ATA based perforator was 10.25cm, on PTA based perforator was 10.6 cm and PA based perforator was 11.8 cm. It was found that in patients in whom the flap length divided by leg length was less than 33%, the chances of flap survival were more as compared to those in whom this percentage was above 33%. In other words there are 5.2 times more chances of flap failure if the flap length is more than 1/3rd of leg length.
Conclusions
This is a simple, versatile technique and is less time consuming with less donor site morbidity. Propeller perforator flaps are best suited in trauma patients with small and medium size leg defects. Peripheral vascular diseases are contraindication for local perforator flaps. The most common complication is venous congestion of the tip or of the entire flap. The average length of flap which can safely be harvested on ATA based perforator is 10.25cm, on PTA based perforator is 10.6 cm and PA based perforator is 11.8 cm. but since the sample size is small, the results need to be verified by a study with larger sample size. These flaps have a limited role in larger defects, degloving injuries especially where the prominent and most near perforator may be within the trauma zone. There are 5.2 times more chances of flap failure if the flap length is ›1/3rd of leg length. This study is an attempt to define safe extent of local perforator fascio-cutaneous flap for lower limb reconstruction based on the size and site of perforators in leg which needs to be substantiated with larger studies.