Influence Of Proximal Tip Location On Partial Necrosis In Distally Based Sural Neurofasciocutaneous Flap: An Analysis Of 157 Flaps

Objective To explore the influence of proximal tip (upper border) location on partial necrosis in distally based sural neurofasciocutaneous flap.Methods The Clinical data and operative pictures of 157 distally based sural neurofasciocutaneous flap were retrospectively reviewed and analysed.From the tip of lateral malleolus to the popliteal crease,posterior aspect of the lower leg was equally divided into 9 regions that were 1st to 9th region from inferiorly to superiorly,respectively.Based on the location of the flaps'proxiamal tip,the flaps were stratified into 4 groups: flaps not beyond the 6th region(group A), flaps located in the 7th region(group B),the 8th region(group C)and the 9th region(group D).The flaps were divided into 2 groups:survival group,including uneventfully survival flaps,the flaps with epidermical necrosis and flaps with wound dehiscence,and partial necrosis group.Harvesting the flaps started from exploring the perforator of personal vessel in the adiofascial pedicle,then elevated the flap retrogradely.Results Of the 157 flaps,125 survived uneventfully,8 showed distal epidermical necrosis,wound dehiscence occurred in 6 flaps,18 flaps (11.5%) showed distal partial necrosis.The differrences between survival group and partial necrosis group in sex,age,site of defects,location of pivot point,total length of falp and adipofascial pedical were not statistically different (P>0.05).Partial necrosis occurred in zero of 19 flaps in group A(0%),1 of 44 flaps in group B(2.3%),7 of 62 flaps in group C(11.3%) and 10 of 32 flaps in group D(31.3%).There were no significant differences in partial necrsis ratio between group B,group B+ group C+ group D and group C,and between group B,group A+ group B and group C(P>0.05), Partial necrosis ratio was higher in group D(31.3%)than in group C(11.3%),in group B+group C(7.4%),in group A+ group B+ group C(6.4%)(P<0.05),it was lower in group A+ group B(1.6%) than in group C+group D(18.1%) (P<0.01).Conclusions Distally based sural neurofasci-ocutaneous flap can survive reliably when the falp's proxiamal tip locate in the regions in lower 7/9 of leg,whereas probability of partial necrosis occuring in the flap increase significantly when the falp's proximal tip locate in the region in upper 1/9 of the leg.