facial nerve decompression

The main purpose of facial nerve decompression is to expose the facial nerve and relieve its pressure, improve blood supply, and promote the recovery of facial nerve function. The surgical approach should be determined according to the location of the facial nerve injury. When the hearing and vestibular function exist, the facial nerve can reach the tympanic section through the ear canal and tympanic approach; from the posterior incision, the tympanic cavity and the mastoidal facial nerve are exposed through the mastoid; cranial The middle fossa approach can expose the inner ear canal segment and the labyrinth segment; the posterior labyrinth can reach the facial nerve of the posterior cranial fossa; through the combined approach of the mastoid and cranial fossa, the whole facial nerve decompression can be performed to preserve the hearing and balance function; Patients who have lost their vestibular function can expose the facial nerve through the labyrinth. Treatment of diseases: facial nerve injury Indication Facial nerve decompression is suitable for Bell's palsy, herpes zoster, tibiofibular fractures, and as a step in other neurological procedures. Decompression is only suitable for cases where the likelihood of natural recovery is small and most of the aneurysms remain intact. Contraindications 1. The muscle has no tension and has no response to direct current. The electromyogram has neither random electrical activity nor fibrillation potential, which is a contraindication for all facial nerve trunk surgery. 2. Patients with acute otitis media within 2 weeks can be treated conservatively. If the facial paralysis is started 10 days later, it may be facial nerve edema, inflammation of the bone tube, and no surgery. However, if the electroencephalogram CAP is >90%, decompression should be considered. 3. Tibial fracture, if the condition is critical after injury, it should be based on life-saving, and the facial nerve repair operation should be performed after the patient's general condition is stable. 4. Patients with severe heart and lung disease, diabetic patients or elderly and infirm, progressive muscular atrophy and blood diseases. Preoperative preparation 1. Do a good job of preoperative interpretation of the patient. 2. Shave the hair in the range of about 6 to 9 cm before and after the ear, and the female patient is licking the knot. Transcranial approach, shave all hair. If the nerve is to be transplanted, the skin is prepared at the nerve site, and the ipsilateral ear nerve or the contralateral medial cutaneous nerve or the ipsilateral sural nerve is generally taken. 3. Clean the auricle and external auditory canal. 4. According to the site of facial nerve injury, the surgical method is selected. The surgical approach is selected. If the injury is in the cerebellopontine triangle, the inner ear canal, the facial nerve labyrinth, and the geniculate ganglion, depending on the situation, the labyrinth, posterior fossa or cranial The fossa approach; 2 facial nerve tympanic section, mastoid section, can be accessed through the external auditory canal or mastoid; 3 parotid gland area, direct access outside the humerus. According to the facial neuropathy, facial nerve decompression, facial nerve anastomosis, facial nerve transplantation and facial nerve-sublingual nerve anastomosis can be performed. 5. Before the operation, 1 day before going to bed and before entering the operating room, each serving phenobarbital 0.09g, allergic to phenobarbital, can take Xixi (Dingding) 5mg (children discretion or not). 6. General anesthesia, soapy water enema before surgery, fasting in the morning, no water. One hour before surgery, 0.5 mg of atropine sulfate was injected subcutaneously (children according to doctor's advice). 7. Apply antibiotics before surgery. Surgical procedure 1. External auditory canal nerve decompression is suitable for the horizontal segment of the sclerosing facial nerve, such as surgical injury and fracture. In this way, the bone fragments and decompression were removed. The sheath damage should be removed and covered with periosteum or fascia. (1) Incision: Make an incision in the ear canal or an incision in the ear. (2) Separate the skin of the ear canal, flip the ear canal flap and tympanic membrane, and expose the middle ear cavity. (3) Use the osteotome or electric drill to enlarge the edge of the external auditory canal upwards and backwards, and remove the outer side wall of the upper drum. The anvil hammer joint, the long anvil bone, the bean-like process and the anvil joint, the hammer stem and the short protrusion, the tibia and the vestibule are visible. The window and the round window and the facial nerve tympanic segment of the bone tube, and then expand the visible facial nerve mastoid segment of the bone tube. Pay attention to avoid excessive communication with the mastoid air chamber, so as not to form a large cavity, and it is easy to be infected in the future. (4) Facial nerve surgery of the external auditory canal approach, if the hearing bone has been damaged by inflammation or surgery, the operation is easier; if the hearing bone is intact, in order to fully expose the facial nerve tympanic segment, the separator is used to separate the anvil joint and free the anvil joint. The anvil is removed with a crochet, and the anvil is repositioned after surgery. There is also the removal of the anvil bone, cutting the hammer bone, this method exposes the tympanic segment, postoperative hearing loss, tympanic membrane osseointegration or the use of autologous or allogeneic bone column to connect the hammer stem and the humeral head to perform ossicular chain reconstruction. (5) Exposing the facial tympanic cavity segment: The anvil is removed, and the facial tube of the facial nerve tympanic cavity is exposed clearly, and different treatments are performed according to the condition of the lesion. If there is a sag or a broken bone to compress the facial nerve, carefully remove the broken bone with a small peel. The pelvic segmental facial nerve tube is thin, and the bone wall is peeled off from the cone section to the outer semicircular canal with a small curette or a distractor to expose the facial nerve. The nerve sheath should be examined for rupture and whether there is bone compression or stab wound in the vicinity. The facial nerve sheath can be edematous or thickened or protruded from the bone. If the facial paralysis has been long, the nerve is edema, but it becomes thinner, the surface is rough, or there is nodular tissue fibrosis, and there is a sign of atrophic degeneration, such as granulation tissue around, it should be completely removed first. (6) Incision of the nerve sheath: from the geniculate ganglion, the facial nerve sheath is cut to the cone section. (7) Closed surgery cavity: If the ossicular chain needs to be reconstructed, the ossicular chain should be reconstructed first. The ear canal flap and tympanic membrane were repositioned. If there was a tympanic membrane tear, the connective tissue was immediately taken for tympanic membrane repair. A gelatin sponge is placed on the surface of the tympanic membrane, the iodoform gauze is stuffed into the external auditory canal, 2. Nerve decompression into the pavement nerve decompression Most patients underwent a mastoid approach for facial nerve decompression. This approach has a wide field of nerve tympanic and mastoid segments. The closure procedure is performed first, and the integrity of the external auditory canal and tympanic membrane is preserved. The facial nerve crypt can enter the posterior tympanic cavity, and the facial nerve tympanic segment and the mastoid segment can be seen. In addition to the use of external auditory canal approach for the sclerosing mastoid, the mastoid approach should generally be used. This approach maintains the normal anatomical location and physiological function of the middle ear and is suitable for patients with good hearing and balance functions. (1) Incision: The incision behind the ear is 0.5-1.0 cm from the posterior edge of the auricle. An arc-shaped incision is made from the upper end of the auricle attachment to the tip of the mastoid to reach the bone surface. (2) simple mastoidectomy: according to the mastoid surgery procedure with a drill or bone to remove the mastoid bone wall, open the sinus sinus, grinding the posterior wall of the external auditory canal, and expand to the entrance of the sinus, expose the horizontal semicircular canal and the anvil Short protrusion, sigmoid sinus second abdominal muscle spasm, middle cranial fossa and posterior fossa brain plate, during surgery, do not damage the anvil bone short process, so as not to affect hearing. (3) exposed facial nerve tympanic segment: can be accessed through the facial nerve crypt, this crypt is a triangular area, the outside is the tympanic nerve, the medial part of the facial nerve is the medial part of the mastoid, and the anvil is the upper part. After the crypt is fully exposed, the cone bulge and the anvil joint, the vestibular window, the round window, the spatula, and the facial tympanic umbilical canal can be seen. The facial nerve approach between the spatula and the geniculate ganglion can be accessed from between the anvil, the outer semicircular canal, and the cranial fossa. Here, attention must be paid to the level of preservation and preservation of the ampulla of the anterior semicircular canal. Decompression of the facial nerve tympanic cavity, the thin part of the bone can be removed from the facial nerve turn to the spatula on the inside of the anvil bone arch (rear arch), and then drilled along the end of the exposed facial nerve tympanic section. After grinding the bones back and down, you can see the facial nerve cone, the tympanic nerve, the mastoid segment and the stem hole. Most authors believe that this path is better than the conventional trans-fascial approach (Kettel). The posterior tympanic approach does not open the external auditory canal, does not touch the tympanic membrane, does not affect the ossicular chain, does not leave the open mastoid cavity after surgery, postoperative Heal quickly. However, in patients with poor mastoid gasification, the field of view is small, the operation is difficult, and the facial nerve is easily damaged. (4) Exposure of the vertical segment of the facial nerve, in addition to the transversal nerve crypt pathway, the vertical section of the facial nerve can also be polished upward through the stem cavity. Use a chisel or electric drill to sharpen the mastoid tip, enter the second abdominal muscle groove from the posterior wall of the mastoid, and a funnel-shaped bone structure at the posterior wall of the proximal ear canal, which is the opening of the stem and the facial nerve from here. Leave the cheekbones. Along the stem of the stem, the diamond bit is used upwards, and the facial nerve tube is gradually thinned. The wall of the tube is eggshell to maximize the exposure of the nerve. The anterior and posterior bone walls of the facial nerve mastoid are first ground into a groove to expose the facial nerve. path. The facial nerve is deep in this section and should be ground under the operating microscope. If you see bleeding in the bone wall, you can use bone wax to fill the bleeding. When grinding to the outer semicircular canal, be careful not to damage the anvil. The facial nerve canal is thinner and the nerve position is shallower. Pay special attention to avoid damage to the nerve. If the bone wall is extremely thin and light blue or the wall is damaged, the lower nerve is visible. The electric drill should be deactivated. Use a small curette or a median splitter to gradually enlarge the wall of the tube until the entire nerve is exposed. Prevent the convex surface of the curette from pressing the facial nerve. (5) Incision of the nerve sheath: from the stem of the stem to the outer semicircular canal, the small cataract knife or a special McHugh knife to cut the nerve sheath, completely decompressed, do not damage the stem and vein arteries during the operation. Because of the simple opening of the facial nerve tube, the swollen nerve is still compressed by the inelastic sheath, so the incision of the nerve sheath is very important for the treatment of ischemic facial paralysis. In cases of suppurative otitis media, the infection is more serious. If there is no obvious edema in the nerve, some people do not advocate incision of the sheath to prevent fibrosis due to long-term infection. However, some people advocate that the sheath is also removed at the same time. The amount of antibiotics is considered to be directly inspected after incision of the sheath, and sufficient decompression is performed, and there is no obvious damage to the nerve fibers. If a small part of the nerve bundle is found to be broken, most of them are intact, and the broken nerve bundle can be trimmed so that the broken nerve bundles can be mutually aligned. If the nerve damage is serious, the facial nerve should be considered for resection and end-to-end. Anastomosis or nerve grafting. (6) Closed operation cavity: After the facial nerve is decompressed, thoroughly wash the bone and blood in the suction cavity with saline, and cover the exposed facial nerve with fascia or gelatin sponge. If it is an open surgery cavity, use the tympanic membrane of the eardrum. The flap covers the facial nerve, the entrance of the sinus sinus and the tympanic cavity. If necessary, the fissure layer is taken from the inner side of the thigh to cover the defect area of the mastoid cavity, and the iodoform gauze is used to fill the cavity. The soft tissue and skin of the incision are sutured in layers with gut or silk. 3. Intracranial fossa nerve decompression can preserve the function of cochlea and vestibular, for facial paralysis patients with good hearing and vestibular function, and gynecologic ganglia, labyrinth and medial auditory facial neuropathy. In the transcranial fossa approach, the auditory canal segment and the labyrinth segment facial nerve surgery can also be combined with the mastoid process to perform facial nerve decompression, or to repair the facial nerve trauma in the proximal segment of the genic ganglia. (1) Incision: Make an incision 2 cm in front of the tragus, vertically upward, to 4 cm on the ear wheel, the incision is 6 cm long. Brackmann changed the incision, not only the postoperative scar was small, but also the intraoperative incision was pulled without tension, and the flap was sutured to the front with a silk thread to enlarge the field. (2) Exposure of the skeletal skeletal bone-building window: the skin, diaphragm and periosteum are bluntly separated after incision, placed in an automatic retractor, in the direction of the muscle fiber, and the temporalis fascia is attached to the zygomatic arch and parallel to the zygomatic arch. Open, at right angles to the direction of the diaphragmatic fibers. Use a drill to open the rectangular plate, or drill a small hole at each of the four corners to form a 4cm × 4cm bone flap. The peripheral part can be sawed by a wire saw and cut into square bone flaps to create a bone window. The bone window is located in the frontal portion of the vertical axis of the external auditory canal, above the iliac crest, and the lower edge of the bone window is as close as possible to the zygomatic arch and its extension line. (3) Remove the bone flap: After separating the bone flap from the dura mater with a blunt dissection device, the bone flap can be gently picked up. The bone flap 2/3 is in front of the external auditory canal. The bone flap bleeding can be stopped by bone wax, and the meninges on the meninges surface. Arterial branch bleeding can be stopped by bipolar coagulation. Be careful not to tear the meninges. (4) Put the House-Urban meningeal retractor or straight retractor and brain plate to lift the meninges from the bottom of the cranial fossa. A traction plate or a brain pressure plate is placed between the meninges and the bone wall. (5) After the meningeal is lifted, there are three important signs in the middle of the cranial fossa, namely the middle meningeal artery, the superficial nerve and the arcuate protuberance. The most important is that the middle meningeal artery is exposed from the spine and runs on the surface of the meninges. It is the most basic sign of cranial fossa surgery. In the posterior aspect of the middle meningeal artery, the superficial nerve is a shallow nerve, which runs between the meninges and the bottom of the cranial fossa. The arcuate protuberance is separated backwards and is a sign of the anterior semicircular canal. The separation of the meninges should not be too deep to prevent damage to the upper sinus. After separation of the meninges between the arcuate protuberances and the middle meningeal artery, care should be taken not to damage the exposed ganglion ganglia, which is absent in 5% to 15% of cases. (6) From the front to the back along the shallow nerve of the rock, the bone is ground with a diamond drill to expose the geniculate ganglion. If the bone is defective, the bone is not needed, the nerve is exposed, and the nerve is not damaged. . The drill is also used to grind the top of the inner auditory canal and the bone inside it to expose the facial nerves of the labyrinth and the inner auditory canal. Care should be taken to avoid damage to the cochlea in front and the semicircular canal in the posterior wall. The tympanic cap must be carefully opened into the upper tympanic cavity to remove a few bones from the outside of the geniculate ganglion, and the facial tympanic cavity can be seen. Continue to use the diamond drill to the inner ear canal, showing that the lost section continues to grind out the inner ear canal. (7) After the facial nerves of the labyrinth segment and the internal auditory canal were exposed, the nerve sheath and the inner ear canal were cut with a small cataract knife or a sharp scalpel for decompression. (8) closed surgery cavity: the internal auditory canal has been opened, in order to avoid cerebrospinal fluid leakage, can be filled with diaphragm. If the tympanic lid is open, the tympanic lid can be closed with bone fragments and fascia. complication 1. Sounding Reasons 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) In the operation, the anvil or the hammer bone can be used to facilitate the decompression of the facial nerve tympanic cavity. After the decompression is completed, the ossicular chain reconstruction should be performed. (3) 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. In order to avoid damage to the inner ear, the facial nerve crypt is advancing, and if necessary, it can swim away from the anvil joint. 3. Cerebrospinal fluid leakage is mainly caused by cerebrospinal fluid leakage through the middle cranial fossa to the dural tear. The local cavity caused by abdominal wall fat, diaphragmatic fascia or fascia and thigh fat filling surgery can prevent this concurrence. disease. 4. 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. 5. Joint movement This is the sequelae of axonal division during the process of degenerative nerve regeneration or the finding of a distal axon tube by some axons. However, this exercise is generally mild and does not cause facial deformities. There is currently no effective therapy. 6. 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. 7. 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. 8. 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. 9. Dynamite nerve damage Because the tympanic nerve enters the tympanic cavity and 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. 10. Facial nerve re-injury mainly refers to aggravating nerve damage in facial nerve decompression. 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. In the operation should avoid the instrument contusion facial nerve or damage facial nerve sheath, especially in facial nerve edema, should pay more attention. 11. 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. 12. Sigmoid sinus injury Note the abnormal position of the sigmoid sinus, sometimes under the mastoid cortex, sometimes with a gas chamber and a deep 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. Prognosis: Patients with facial nerve decompression experience facial paralysis and beating soon after surgery, and can gradually resume spontaneous movement. The oral activity first appeared, and then the movements of the upper lip, the nose and the closed eye gradually recovered, and the wrinkle movement recovered the worst, and often was incomplete, and there was a joint movement. After the symptoms of the Bell facial paralysis, the decompression period should be selected according to the signs of recovery of various electrical reactions. The tympanic membrane remained intact, and the postoperative hearing loss was only 10-15 dB before surgery, which had no effect on daily life and work. 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.