facial nerve transplantation

Nerve transplantation mainly grasps 3 points: 1 nerve defect exceeds 5mm; 2 requires extensive transfer of nerve to perform end-to-end anastomosis, which may seriously damage nerve or blood vessel; 3 nerve anastomosis has tension. Treatment of diseases: facial nerve injury Indication Facial nerve transplantation is suitable for cases with large facial nerve defects (4~5mm), which can not be anastomosed. It is also suitable for nerve cutting, fracture and trauma caused by trauma or surgery. Surgical procedure 1. Incision and surgical cavity treatment Incision and surgical cavity treatment are the same as "face nerve decompression". 2. Transplantation nerve resection method Ear nerves, medial cutaneous nerves or sural nerves can be used, but the ear nerves are most commonly used. Large ear nerve cutting method: In the middle of the ipsilateral sternocleidomastoid muscle, the skin and subcutaneous tissue are cut transversely, and the nerve can be found on the surface of the sternocleidomastoid muscle. When the auricular nerve is accompanied by the external jugular vein, when the external jugular vein is exposed, the auricular nerve can be found by separating it by about 1 cm. After separation to the required length, the ends are cut with a sharp knife, and the cut nerve segments need to be about 0.5 cm longer than the deficient nerves. Immediately after removal, the implanted bed was implanted to coincide with the two ends of the facial nerve. Advantages of taking the large ear nerve: 1 anatomy of the large auricle is easy to grasp, after the ear nerve is removed, the effect on the sensory is small; 2 the nerve thickness of the ear is the same as that of the facial nerve, and its length is sufficient for facial nerve transplantation; The nerves are exposed in the same surgical field. The medial cutaneous nerve cutting method: a 6~8cm transverse incision is made from 10cm below the groin or a palm of the hand. Cut the skin, superficial fascia and subcutaneous fat to the fascia, you can see the great saphenous vein. Separation of the fascia lata, 2 to 4 cm outside the great saphenous vein, can be seen that the anterior branch of the medial cutaneous nerve descends from the shallow surface of the sartorius muscle. When separating the nerve, pay attention to the same as taking the ear. The nerve should be removed immediately and the incision should be sutured layer by layer. The method of cutting the sural nerve; after the external hemorrhoids, make a 3cm incision to separate the skin and subcutaneous tissue. After a small vein, the sural nerve can be seen, and the longitudinal stripping can be done. The second or third can be made above it. The stepped incision is then released, and the nerve is removed by cutting the upper and lower ends. 3. Probe of nerve breaks The anatomical relationship between the facial nerve stroke and the vulnerable structure must be mastered. The location of the nerve graft depends on the extent of the lesion and the injury. The more common sites are the horizontal segment and the vertical segment. The proximal end is above the vestibular window and behind the spatula. The position is fixed and easy to find. The facial nerve horizontal segment is slightly backward from the front. Go down. The second half of the horizontal section is located above the vestibular window and is shallow and low in location, subject to damage. The distal end varies depending on the degree of injury. It can be in the cone section or near the stem of the stem. When searching, the bone wall behind the external auditory canal should be ground. The vertical section is inclined from the front to the back, and the upper part is close to the vestibular window and the lower part is posterior. It is not difficult to find the mastoid segment by grasping the distance between the facial nerve and the drum ring. The mastoid segment can be found by exposing 1 cm to the deep part of the bulge. If a suspicious break is found and cannot be determined, an electrical stimulation test can be used. If the nerve is broken, some muscles on the patient's face will be twitched after the stimulation. 4. Transplantation Before implanting the nerve, the nerve used for transplantation must be removed under the microscope to remove the connective tissue around it, leaving only the nerve sheath, and the two ends of the nerve are cut with a sharp knife to avoid extrusion. It is necessary to remove the local granulation, fibrous tissue, and bone and blood clots of the facial nerve itself. If the transplanted bone tube has a large defect and no groove, it must be reground into a bone groove. Both ends of the bone groove must form a slope with the remaining bone tube, which can promote the tight joint of the broken end and the transplanted nerve. Use a sharp knife to remove the neuroma to the normal end and trim the two ends. Place the transplanted nerve in the grooved bone tube without suturing. The section can be adhered to each other by exuding plasma. In patients with facial nerve defects, the graft nerve and the facial nerve are sutured with a 9-0 non-invasive nylon thread. The tissue glue can also be used to bond the surrounding area with the venous catheter of the mantle. The nerve tissue is attached to the surface of the mastoid cavity without tension, covering the fascia or gelatin sponge, and then covering the mastoid cavity or the middle ear cavity with a thick blade of skin, and stuffing with iodoform gauze, not too tight, to avoid the compression of the transplant nerve. complication 1. The reasons for the pronunciation are: (1) Perforation of the tympanic membrane, accidental injury when separating the posterior wall of the external auditory canal or the tympanic cavity, if there is perforation repaired with fascia. (2) The dura mater is sagged through the defect of the tympanic cap, which hinders the function of the ossicular chain. The tympanic cap is reconstructed with bone fragments and fascia after closing the inner ear canal and covering the facial nerve after intra-canal or incisional facial nerve surgery. 2. Sensorineural hearing loss caused by intraoperative injury, vestibular or cochlea, or vibration transmitted to the inner ear due to the removal of bone around the incus. 3. Permanent facial paralysis This is the result of the inability of the degenerated nerve to regenerate. It can be corrected by fascia sling or facelift. 4. Joint movement This is the sequelae of axonal division during the process of degenerative nerve regeneration or the loss of some axons to find a distal nerve sheath. However, this exercise is generally mild and does not cause facial deformities. There is currently no effective therapy. 5. Nerve regeneration of facial muscle contracture degeneration After re-domination of muscles, some facial muscles often have different degrees of contracture. Often expressed as nasolabial area. This contracture is only noticeable when the healthy side is free to move. The two sides of the face remain symmetrical at rest, so there is no need for treatment. 6. Facial twitching and sputum regaining innervation of the facial muscle can sometimes have permanent paralysis, the lighter manifests as eyelid twitching, and the severe manifestation of severe paroxysmal spasm of the entire affected side. The cause of the disease is unknown, and there is currently no specific treatment. Some people use botulinum toxin type A injection therapy is effective. 7. Crocodile tears are also known as Tear Syndrome or Bogorod syndrome. Because of skull base fracture, surgical injury, and Hunt syndrome, the geniculate ganglion is damaged. After the function is restored, the patient can shed tears every time they eat, which is permanent and limited to the temporal side. This is caused by the nerve impulses secreted by the parotid gland into the lacrimal gland. Impulsive conduction errors may be caused by the reentry of the parotid nerve fibers into the path, which constitutes the connection between the superficial nerve and the tympanic plexus. Bu Guoxian (1994) reported that conservative treatment of sphenopalatine nerve closure, 6 months without reduction can be surgically cut off the tympanic nerve and tympanic nerve, or cut off the ductal nerve. There is no such phenomenon after surgery to cut off the great superficial nerve. 8. Dynamite nerve damage Because the tympanic nerve enters the tympanic cavity, it walks between the hammer stem and the long foot of the anvil. It is easy to damage the nerve in the tympanic operation, and the tympanic nerve should not be excessively involved during the operation. If it interferes with the field, it would rather cut off. 9. Facial nerve re-injury mainly refers to aggravating nerve damage in facial nerve repair. Thus affecting the recovery of postoperative neurological function. Avoid burns when using an electric drill. When approaching the facial nerve, you should use a diamond drill bit to avoid bumping the facial nerve. Use a facial nerve stimulator for a period of no more than 1 s to avoid burning the nerves. 10. Jugular bulb injury Any sacral surgery should prevent the jugular vein from being damaged. Especially when entering the inner surface of the facial nerve mastoid, the jugular bulb can be raised to the inner surface of the facial nerve, sometimes as high as the posterior foot of the posterior semicircular canal. Injury causes severe bleeding. 11. Sigmoid sinus injury Note the abnormal position of the sigmoid sinus, sometimes under the mastoid cortex, sometimes with a gas chamber and the sigmoid sinus position. Sometimes moving forward, almost close to the posterior wall of the external auditory canal, should always pay attention, and often flush the surgical cavity to keep the surgical field clear. Traumatic facial paralysis, if the nerve is not broken, remove the hematoma or broken bone pieces and then decompression, most of them begin to recover from 10 to 90 days, and also recover completely in 4 to 6 months or 1 year. The effect of the end-to-end anastomosis is better, and the tiny function can be quickly restored. If the connective tissue grows from the anastomosis, the axonal regeneration is hindered and the anastomosis is failed. Anastomotic axonal regeneration dislocation can lead to poor recovery of facial muscle function. The recovery of nerve transplantation is slow, and the recovery time is closely related to the height of the nerve graft, and it varies depending on its location and length. The brain stems recover slowly, and the recovery of the humerus or the humerus is faster. Can cause poor recovery of function. Nerve transplantation is slower to recover, at least 4 to 6 months after surgery, and recovery begins after 2 years, most of which can only reach about 80%. There are generally different degrees of sequelae. Fisch (1976), Anderl (1973, 1976), Gurg-Bob (1980), Wang Dezhao (1985) Fan Zhong (2000) have reported on several cross-face nerve grafting, the main principles of which will be The nerve impulses of the main branch of the facial nerve (union, buccal branch, and mandibular branch) without lateral damage are cross-linked through 3 to 4 nerve segments or transmitted through the transplanted sural nerve to the corresponding facial nerve branch of the affected side, thereby making the face The expression muscle regains innervation. In order to achieve functional recovery, the muscles of the sputum must still have the ability to regenerate, and the time of sputum should preferably not exceed one year. If the facial muscles have shrunk and there is fibrosis and facial nerve graft failure, the use of chewing muscle or diaphragmatic pedicle transfer for cutaneous nerve regeneration or fascia levee suspension, as well as the application of palmar tendon dermis and Silica gel, PTFE and other materials are suspended and the effect is satisfactory. Transcutaneous nerve transplantation combined with free muscle transplantation and vascular neuromuscular valve transplantation have also been reported. For patients with advanced facial paralysis, patients with healthy body, age below 60 years old, and one side facial paralysis are recommended to use vascular neuromuscular flap transplantation. It was reported that the first-stage transplantation of the small musculocutaneous graft or the super-long pedicle segmental latissimus dorsi muscle flap was used to treat the late facial paralysis.

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