Septocutaneous Perforator Patterns Of The Medial Arm Flap And Its Clinical Applications

Objective:This study aimed to investigate the septocutaneous perforator patterns of the medial arm flap,the predominant source vessels and the vascular anastomosis among different perforasomes.Based on these perforators,the clinical applications of the medial arm flap were introduced and several novel designs were developed.The value of intraoperative indocyanine green SPY imaging was evaluated.Methods:?21 arms of 20 consecutive patients who underwent medial arm flap surgery were included in the study.A reference coordinate system was set up,in which the y-axis joined the medial epicondyle to the axillary apex.The total length of the arm was measured and designated as 1.The arm was divided into three parts and the perforators of the proximal,the middle and the distal part were designated as A,B and C,respectively.The first perforator of the proximal part and the last perforator of the distal part were designated as Pp and Pd.The number,presence rate,location and size of perforators were recorded and analyzed.?Four red-latex injected upper limbs were dissected.The septocutaneous perforators of the medial arm and the source vessels were identified.Twelve fresh cadavers were injected using the lead oxide-gelatin injection technique,then imaged using a spiral computed tomography scanner.Three-dimensional reconstructions of the septocutaneous perforator angiosomes in the medial arm were performed using Materialise's Interactive Medical Image Control System software.The anastomosis between adjacent peforasomes was analyzed.?Based on the septocutaneous perforators,the medial arm flap was used as proximally or distally based pedicle flap and perforator-based propeller flap.A novel approach of total cheek reconstruction was introduced with the pre-expanded medial arm flap,while the donor site was closed using a pedicle axial back flap.The flap survival and complications were reviewed and the postoperative symmetry of bilateral arms was analyzed.?Indocyanine green SPY imaging was used intraoperatively to evaluate the flap perfusion and predict necrosis.The sensitivity,specificity and accuracy were calculated respectively.Results:?A total of 95 perforators were identified in 21 arms,with an average of 4.5 perforators(range,3 to 8).Perforator A with a total number of 32 was present in 95.2 percent of cases and located 0.87 ± 0.09 from the medial epicondyle.The proportion of the medium-and large-sized(M and L)perforator was 78 percent.Perforator B with a total number of 33 was present in 100 percent and located 0.49± 0.09,with a proportion of 55 percent of M and L perforator.Perforator C with a total number of 30 was present in 85.7 percent and located 0.20±0.06,with a proportion of 47 percent of M and L perforator.Perforator Pp with a total number of 20 was present in 95.2 percent and located 0.92 ±0.06,with a proportion of 90 percent of M and L perforator.Perforator Pd with a total number of 18 was present in 85.7 percent and located 0.17±0.05,with a proportion of 56 percent of M and L perforator.? 17 perforators were identified in 4 specimens and 13(76.5 percent)originated from the brachial artery directly.The perforators of the brachial artery,superior ulnar collateral artery and inferior ulnar collateral artery were demonstrated clearly in three-dimensional view by using Mimics.True anastomosis was found linking adjacent perforasomes along the longitudinal axis of the arm in a curved shape.?42 medial arm flap surgery were performed in 36 patients,including 29 proximally or distally based pedicle flaps and 13 perforator-based propeller flaps.The locations of the defects included head and neck(n = 26),axilla(n = 7),elbow(n = 4),hand(n = 3),and chest(n = 2).3 patients had a total unilateral cheek defect.3 pre-expanded medial arm flaps were separately used for cheek defect reconstruction,with the donor sites in the medial arm closed using a pedicle parascapular flap and 2 pedicle thoracodorsal artery perforator flaps.The maximum dimension of the medial arm flap was 22×15cm and the minimum lO×4cm.7 flaps suffered superficial or full-thickness necrosis in the distal part of the flap and healed secondarily with conservative or surgical management.The remaining survived completely.The circumferences of bilateral arms were measured postoperatively and a good symmetry was preserved.The patients were followed up routinely and all were satisfactory with the final results.?Indocyanine green SPY imaging was used in 13 flaps of 12 patients with a sensitivity,specificity and accuracy of 66.7%,80.0%and 76.9%,respectively.Conclusions:The blood supply of the medial arm flap was predominantly based on the septocutaneous perforators of the brachial artery.The constant perforators could be found in the proximal,middle and distal part.True anastomosis linked theses perforasomes in a curved shape.Based on the septocutaneous perforators,the medial arm flap could be used as a proximally or distally based pedicle flap and a perforator-based propeller flap,with great versatility and reliability,to reconstruct the defects of head and neck,axilla,elbow,hand,chest and even the breast.Intraoperative indocyanine green SPY imaging was a valuable adjunct to evaluate the flap perfusion and prevent necrosis.