DATA AND METHODS I. GENERAL DATA There were 182 cases in this group, 130 males and 52 females. The onset time was from 1 month to 18 years, with an average of 2.3 years. There were 106 cases on the right side and 72 cases on the left side (4 cases were bilateral). The grading of the cases was based on the standard of functional ulnar nerve evaluation of the upper limb of the Society for Surgery of the Hand of the Chinese Medical Association, and all cases showed persistent paresthesia, claw row closure deformity, and slowing of motor nerve conduction velocity at the elbow, which was considered to be of severe degree. The rate of lost visit in this group was 52.1%, and there were 89 cases with complete follow-up, including 8 cases of ulnar nerve in situ release, 42 cases of intrafascial flap anterior release, 35 cases of subcutaneous anterior release, and 4 cases of intramuscular anterior release. The follow-up period ranged from 3 months to 6 years, with an average of 2.5 years. Evaluation items The functional ulnar nerve evaluation standard of the upper limb of the Chinese Medical Association Society for Surgery of the Hand was used, and the functional evaluation standard of elbow-tube syndrome was used for the follow-up[1] . Surgical methods Among the patients who were followed up, the surgery was divided into in situ release and subcutaneous anterior, subfascial anterior, and intramuscular anterior. Brachial plexus anesthesia was used, and the ulnar nerve with a vascularized deep fascial flap was placed under the anterior position: centered on the supraspinatus humerus, an arcuate forward incision was made on the medial side of the elbow with a length of about 350px, and the anterior edge of the arcuate incision was 87.5px away from the supraspinatus humerus.The superficial subcutaneous fascia was separated from the elbow back to the supraspinatus humerus, and then a deep fascial flap with a size of 100pxxx100px and a tip of 100px was formed on the surfaces of the pronator teres and the flexor muscles, and the flaps were set aside. A deep fascial flap was formed on the surface of the pronator teres and flexor muscles from front to back. Under the microscope, the ulnar nerve was accompanied by the ulnar superior collateral artery, the posterior branch of the ulnar collateral artery and the ulnar inferior collateral artery together with the ulnar nerve were moved anteriorly; the ulnar nerve trunk was separated, and the elbow branch was excised, preserving the muscle branch. The ulnar nerve was freed proximally along the ulnar nerve to 200px above the medial epicondyle of the humerus, and the arch of the Struthers was cut off, and distally to about 150px from the medial epicondyle of the humerus, which was freed from the ulnar flexor carpi ulnaris muscle between the two heads. If the ulnar nerve is thickened and hardened, it is feasible to release the nerve epineurium or fasciculus. For those without inter-bundle fibrosis, the nerve epineurium was released, i.e., the external scar of the nerve trunk was loosened and the thickened nerve epineurium was excised to relieve the external compression of the nerve; and for those with inter-bundle fibrosis, fasciculotomy was performed to decompress the nerve under the microscope. Place the ulnar nerve anteriorly on the surface of the pronator teres muscle and flexor muscle, wrap the anterior ulnar nerve with a fascial flap, and make a transverse mattress suture between the end of the fascial flap and the anterior subcutaneous fascia of the elbow, and pay attention to avoiding that the ulnar nerve becomes an angle under the fascia, which will form a new compression. Move the elbow joint to check for excessive pulling and twisting of the ulnar nerve after anterior placement, and make sure that the inner diameter of the ulnar nerve channel is greater than 37.5px to prevent the formation of new entrapment. Subcutaneous anterior placement:A longitudinal incision of up to 175px was made centered on the posterior 37.5px of the medial-superior humerus bare to avoid injury to the medial cutaneous nerve of the forearm. After the ulnar nerve is freed from the elbow canal, it is placed anteriorly under the skin of the medial humeral condyle, and the subcutaneous tissue on the anterior side of the incision is sutured to the deep fascia underneath the incision several times to prevent the ulnar nerve from slipping back into the elbow canal. When incising the elbow canal, avoid damaging the muscle branch of the ulnar flexor carpi ulnaris, and separate the muscle branch from the nerve trunk appropriately. The length of the ulnar nerve should be appropriate, and sometimes the elbow joint branch can be cut off for complete anteriorization of the ulnar nerve. Intramuscular anterior approach: The incision is the same as the subcutaneous anterior approach, and after the ulnar nerve is freed from the elbow canal, it is placed anteriorly in the muscle groove of the pronator teres muscle and ulnar flexor carpi ulnaris muscle. The muscle membrane was closed with several sutures. Of the 89 patients in our group, 42 ulnar nerves were anteriorly placed under a deep fascial flap with vascular tibiae, and 35 ulnar nerves were anteriorly placed subcutaneously. Intramuscular anterior placement was performed in 4 cases, and in situ release was performed in 8 cases. All patients were fully hemostatic during surgery, drainage was placed in the incision, and trimethoprim was injected with 40 mg of trimethoprim next to the nerve periphery; after surgery, they were immobilized with plaster casts in the functional position of elbow flexion for 3 weeks, and neurotrophic medication and neuroelectrical stimulation were applied to promote the recovery of nerve function. Results 3~4 months after the operation, all the patients had a better recovery of symptoms, claw walking hand deformity and small fissure, the first interosseous dorsal muscle atrophy was controlled and gradually recovered, the numbness and tingling sensation grasped and recovered, and it was found that more than half a year through follow-up, the degree of recovery didn’t increase with time again. Ulnar nerve with vascular tibia deep fascia flap under the anterior placement of 42 cases, the excellent rate of 97.6% (41/42) to perform subcutaneous anterior placement of the ulnar nerve in 35 cases, the excellent rate of 74.3% (24/35). Intramuscular anterior placement was performed in 4 cases, with 2 excellent cases and 2 good cases. In situ release surgery was performed in 8 cases, with 2 cases excellent, 4 cases good and 2 cases poor. There was no statistically significant difference between age and surgical efficacy (p=0.281), gender and surgical efficacy (p=0.654), left and right side and surgical efficacy (p=0.131), and the difference in scores between surgical methods and surgical efficacy was statistically significant for the 4 groups in general (p=0.002), but the difference in scores for two-by-two comparisons of the fascial flap method and the intramuscular anterior approach were not statistically significant (p=0.001), and the differences in scores between the other groups were statistically significant. DISCUSSION Surgery is an inevitable option when elbow-tube syndrome progresses to moderate-to-severe levels. The current debate is which neurosurgery to use. At our institution, we use in situ release and subcutaneous anterior, subfascial anterior, and intramuscular anterior. Our clinical observation shows that whether or not anterior placement is used is highly related to whether or not the ulnar nerve is released, the amount of tension on the ulnar nerve in the flexed and extended elbow joint, and whether or not the ulnar nerve slips anteriorly toward the medial epicondyle of the humerus. If the tension of the ulnar nerve at the flexion/extension elbow joint is high or the ulnar nerve tends to slip anteriorly toward the medial epicondyle of the humerus, then anterior nerve placement will be used, and we use the fascial flap anterior, subcutaneous anterior, and intramuscular anterior methods. Although the difference in scores between the fascial flap method and the intramuscular method was not statistically significant, this was related to the lower number of intramuscular laws. The intramuscular method is associated with more bleeding and heavy postoperative adhesions, and although it is used less clinically, some surgeons are still accustomed to this method. In this study, there was no statistically significant difference between age, sex, and left and right sides and prognosis, and the comparison of fascial flap method and subcutaneous method was emphasized, and the score of fascial flap method was 12.9 on average, and the score of subcutaneous method was 10.3 on average, and the rate of excellence of fascial flap method was high. Fascial flap method and fascial flap method The use of vascularized ulnar nerve fascial flap under the anterior position for the treatment of elbow tube syndrome: 1, after the elbow skin incision, the deep fascial flap of the free should pay attention to the protection of the skin’s blood flow, in order to ensure the thickness of the deep fascial flap at the same time to avoid injury to the skin’s subdermal vascular network. The length-to-width ratio of the fascial flap should reach l:1, and the fascial flap should be fixed with transverse mattress suture to prevent the formation of new pressure points on the ulnar nerve at the suture line. The potential sites of ulnar nerve impingement (Struthers’ tendon arch, medial interosseous interval, Osbome’s fascia, ulnar flexor carpi ulnaris tendon membrane, and flexor digitorum communis tendon) should be completely opened during the operation. In this group, an average of 2.2 entrapment points were found in each patient during the operation. Other causative factors included trauma, swelling and unknown causes, and all possible entrapment factors should be removed during the operation. 3. The joint and muscle branches of the ulnar nerve should be fully freed under microscopic vision, and the degree of freedom of the ulnar nerve should be observed when the elbow joint is flexed and extended, so as to avoid generating a large tension and forming a new entrapment after the anterior placement. 4. Under the microscope, the superior ulnar collateral artery, ulnar collateral artery, inferior ulnar collateral artery and ulnar nerve were freed anteriorly. Finding the muscle branch of the superior ulnar collateral artery and ligating it can increase the blood perfusion pressure of the superior ulnar collateral artery to the ulnar nerve. 5. If the ulnar nerve has thickening, degeneration, or adhesion to the surrounding tissues, release of the nerve epineurium or intertriginous bundles is performed. The ability to microscopically visualize the filling of the peripheral vessels and the intertubercular vessels after release is an indicator of complete nerve release. The advantages of this procedure compared with the traditional anterior ulnar nerve placement are that the anterior placement of the ulnar nerve can provide a soft nerve bed, avoiding re-entrapment of the nerve, and the use of microsurgical techniques to ensure the blood supply of the ulnar nerve after the anterior placement, which is easy to operate and easy to be popularized. The complete release of nerve entrapment factors after nerve transposition, the good quality of the nerve bed and the smoothness of the nerve channel, as long as these three requirements are met, both surgical methods can achieve satisfactory results. However, from our study, the fasciocutaneous flap method is better than the subcutaneous anterior method and is worth promoting.