Applied Anatomic Study Of Di-pedicle Gastrocnemius Myocutaneous Flap In The Treatment Of Soft Tissue Defect Around Heel Combining Achilles Tendon Defect And Clinical Report

Objective: To provide anatomic basis for di-pedicle gastrocnemius myocutaneous flap in the treatment of soft tissue defect around heel combining Achilles tendon defect and confirm the results of the anatomic study in the clinical work. Methods: (1) On 30 adult cadaver specimens of lower limbs, operations were simulated to harvest the gastrocnemius myocutaneous flap. The structure and the relationship of the flap and the tissue around it were observed, while the distance that the flap can glide in different conditions were tested too; (2) Two clinical operations were performed. Results: (1) Both initial sections of media and lateral head of the gastrocnemius were divided into two parts: tendon and muscle. The tendon part of the media head was triangular and both tendon parts of the gastrocnemius were connected to the knee joint capsule partly. The nerve and blood vessel pedicle run the muscle in the muscle part. The distance between the initial point of the muscle part and the position of the nerve and vessel pedicle coming into muscle were (7.2±1.4)cm of the media head and (5.9±1.3)cm of the lateral head. (2) The arteries of the gastrocnemius myocutaneous flap can be divided into 4 types: A. Sural artery originated from popliteal artery singly; B. The medial and lateral sural artery originated from popliteal artery singly and either of the artery sent a branch to the contralateral head; C. Sural artery originated from the same branch of popliteal artery; D. Sural artery originated from popliteal artery singly and at least one head had two arteries. (3) According to its course, the nerve of the gastrocnemius myocutaneous flap that originated from tibial nerve can be divided into 6 types: A. The medial sural cutaneous nerve and the muscular branches innervating medial and lateral head of gastrocnemius and the soleus muscular originated from the tibial nerve singly; B. The medial sural cutaneous nerve and muscular branch innervating medial head of gastrocnemius originated from the same branch of the tibial nerve; C. The muscular branches innervating lateral head of gastrocnemius and the soleus originated from the same branch of the tibial nerve; D. The medial sural cutaneous nerve and muscular branch innervating medial head of gastrocnemius originated from the same branch of the tibial nerve, and the muscular branches innervating later head of gastrocnemius and the soleus muscular originated from the tibial nerve; E. The medial sural cutaneous nerve and the muscular branches innervating medial and lateral head of gastrocnemius and the soleus muscular originated from the tibial nerve; F. The medial sural cutaneous nerve and the muscular branch innervating medial and lateral head of gastrocnemius originated from the tibial nerve. (4) According to its course the nerve of the gastrocnemius myocutaneous flap originated from common peroneal nerve can be divided into 3 types: A. The lateral sural cutaneous nerve haven't any branch to the medial sural cutaneous nerve; B. Lateral sural cutaneous nerve sent a branch to medial sural cutaneous nerve; C. Common peroneal nerve sent a branch to the medial sural cutaneous nerve directly. (5) When the original part of gastrocnemius were not incised, the distances that the gastrocnemius myocutaneous flap can glide were (1.4±0.4)cm when the knee joint flex 0°and (3.3±0.4)cm when the knee joint flex 90°;when the original part of gastrocnemius were incised zigzag, the distances it can glide are (3.7±0.5)cm when the knee joint flex 0°and (4.9±0.7)cm when the knee joint flex 30°and (6.7±0.7)cm when the knee joint flex 60°and (9.2±0.9)cm when the knee joint flex 90°. (6) The correlation between the length of leg and the longest gliding distance of the flap were: 36-37cm with(8.0±0.5)cm,38-39cm with(9.2±0.7)cm,40-43cm with(9.6±0.9)cm; different types of the nerve that originate from tibial nerve and the longest average gliding distance: A with (9.0±0.8)cm,B with (9.0±1.2)cm,C with (9.2±0.5)cm,D with (8.9±0.9)cm,E with (10.3±1.1)cm, F with 9.5cm;different types of the arteries and the longest average gliding distance of the flap: A with(9.2±09)cm,B with (9.2±0.9)cm,C with(10.2±0.6)cm,D with (8.0±0.4)cm. (7) Both cases got a good results of the treatment. The defects were repaired completely and the function of the knee joint and ankle joint were regained.Conclusion: (1) When the original parts of gastrocnemius were incised zigzag, the incision should be located between the borderline of the tendon part and muscle part. And a thin rear layer of tendon part should be combined with the muscle section while the side of tendon part which adhere to the knee capsule should be kept integrity; The incision of original parts of gastrocnemius should be above the point that the main nerve and vessel pedicle come into muscle and the longest average length it can extend is (7.2±1.4)cm of media head and (5.9±1.3)cm of lateral head. (2) The nerve and blood vessel aren't all the same in different specimens and variance exist; According to its course the nerve of the gastrocnemius myocutaneous flap that originated from tibial nerve can be divided into 6 types; According to its course the nerve of the gastrocnemius myocutaneous flap that originated from common peroneal nerve can be divided into 3 types; The arteries of the gastrocnemius myocutaneous flap can be divided into 4 types. (3) The gliding distance of the di-pedicle gastrocnemius myocutaneous flap go up with the knee joint flexion and the distance become even more great after the original parts of gastrocnemius were dissected; When the knee joint flexed 90°and incised the original part of gastrocnemius was dissected, the distance that the flap can glide was the longest one; the longest distance that the flap can repair was (9.2±0.9) cm; Maybe there are mutuality between the length of the leg and the longest gliding distance, but there isn't proof significant difference of the longest average gliding distance among different types of nerve and blood vessels. (4) Di-pedicle gastrocnemius myocutaneous flap is suitable to repair Achilles tendon defect combining soft tissue defect around heel, but the defect should within the distance that flap can repair and more attention must be paid to the variation in harvesting.