Acoustic neuroma resection via retrosigmoid approach

After the sigmoid sinus approach, the auditory neuroma resection has a wide field of view, and the cerebral cerebellar triangle pool is clearly visible. After the posterior cranial fossa, the posterior wall of the inner ear canal can be removed from the inside and the outside with a long drill bit, and the tumor tissue in the inner ear canal can be fully exposed and completely removed. It is also possible to remove the posterior wall of the inner ear canal and complete the tumor resection in the inner auditory canal by means of endoscopy. Treating diseases: acoustic neuroma Indication Transsphenoidal posterior approach for acoustic neuroma resection is applicable to a variety of cases in which the mass of the tumor is in the cerebral cerebellar triangle pool, including cases with better hearing function or facial nerve function. Because the surgical approach is far from the middle and inner ear structures, it is conducive to preservation of hearing. Preoperative preparation 1. Learn more about the medical history, review the hearing function, vestibular function, facial nerve function test data and image examination photos, and strive to make the qualitative and quantitative positioning diagnosis correct. 2. Prepare skin 1 day before surgery and use anti-infective antibiotics. 3. Preoperative night enema, taking sedatives before going to bed. 4. In the morning, the water is forbidden and fasted. 5. Half an hour before surgery, atropine sulfate 0.5mg was injected subcutaneously. 6. Pay special attention to cases with high intracranial pressure. Before use, use dehydrating agent or ventricle puncture, and indwell the decompression tube to ensure intraoperative safety. Surgical procedure Disinfection The scalp and the skin around the ears, cheeks, and neck pillows were routinely sterilized with 2.5% iodine and 75% ethanol. Assemble the sterile surgical table as required and fix it on the skin around the field. 2. Incision After the ear, the internal sacral incision is made, and the upper part of the auricle attachment line is upward, 4 to 5 cm backward, and extends downward to about 2 cm behind the mastoid tip, and stops at 1 to 2 cm below the tip of the mastoid. Deep to the bone surface, the skin and soft tissue are separated from the skull surface and turned forward. 3. Skull opening window Taking the extension line of the sacral line as the upper boundary, the line connecting the apex of the humerus and the tip of the mastoid is the front boundary, and the bone of about 3cm×4cm is cut off at the junction of the apex, the occipital and the ankle, and the side of the posterior cranial fossa is exposed. The dura mater has a transverse sinus in the upper part and a posterior edge of the sigmoid sinus in front. The anterior part of the bone is a tibia, thicker, can meet the mastoid blood vessels, and there may be a gas chamber communicating with the mastoid and the sinus. It must be tightly sealed to reduce bleeding and avoid cerebrospinal fluid. 4. Cut the dura mater to reveal the cerebral cerebellar triangle pool After half an hour of rapid input of 20% mannitol 250ml, the meninges can be cut with a curved incision or a radial incision, and should be kept at a distance of more than 2 mm from the transverse sinus and the sigmoid sinus to avoid bleeding. The dura mater is sutured and retracted, and the anterior lateral surface of the cerebellar hemisphere can be seen. The groove is clear, fine and yellowish, and the surface of the pia mater is rich in blood vessels, often expanding obviously. The brain plate is placed from the back to the front, and the cerebellar hemisphere is gently pushed to the inner side. Under the protection of the brain cotton, part of the cerebrospinal fluid is aspirated, and the cerebral cerebellar triangle pool can be revealed. The front is the back of the sacral rock, the upper part is the cerebellum, and the lower part is the posterior cranial fossa. The tumor is centered and close to the posterior surface of the rock. If the tumor is small, the vein and trigeminal nerve can be seen deep in the anterior and superior anterior and the IX, X, and XI cranial nerves are seen at the base of the skull. . 5. Isolation and removal of tumors There is a capsule on the surface of the tumor, which is distributed with blood vessels that travel forward and backward. The color is significantly different due to different tumor structure types. Atoni type I is often grayish white, slightly pink in the middle, and rich in blood vessels; Atoni II is often dark yellow, very similar to subcutaneous fat tissue, sometimes with different color interlacing. After gently pushing the cerebellar hemisphere with a brain pressure plate, put the brain cotton to separate the tumor to avoid damage. If the tumor is small, the pial membrane around it can be directly separated, and the blood vessel connected thereto can be cut by bipolar electrocoagulation, the central side of the artery can be seen and cut, and the pedicle in the inner ear canal can be exposed and excised forward. Most of the masses are grown by the inner ear canal. For complete resection, the posterior wall of the inner ear canal should be removed from the inside out. The method is to first cut the bone coat of the posterior wall of the inner ear canal, separate it upwards and downwards, expose the bone surface, and then use the long cutting bit to remove the bone until the pink color appears, and then use the diamond bit to continue to grind until the tumor is exposed. Until now. The tumor and surrounding tissues were alternately separated by small nerve hooks and strippers. At this time, it is necessary to pay special attention to the fact that the face god is often squeezed between the tumor and the bone wall in the front upper part, sometimes flat and slender, and is easily pulled and injured. When it is known that the abnormal reaction on the monitor, it should be suspended immediately. Adjust the operation method. By separating and cutting the connection between the tumor and the vestibular or cochlear nerve from the bottom of the inner ear canal, the mass can be gently lifted and removed. If the tumor is large in volume, it can be in contact with the cerebellum and extend to the cerebellar incision. The lower part is close to the cranial fossa, and the cranial nerves and blood vessels cannot be peeped. At this time, the blood vessels on the capsule should be electrocoagulated, the capsule should be cut, and the tumor capsule should be removed by suction cutting, ultrasonic aspirator or tissue forceps (with a tumor forceps) until the capsule is empty and the tumor tension is reduced. The tumor capsule is separated from the surrounding tissue (pial membrane, blood vessel, nerve tissue, cerebellum) from the top down or the bottom, and the nourishing blood vessels on the surface of the tumor are electrocoagulated. Finally, the brain stem side is separated, and the tumor can be completely removed. When separating larger tumors, besides paying attention to facial nerves and rock veins, attention should be paid to the protection of the lateral surface of the brainstem. The anterior inferior cerebellar artery is often smashed into sputum, attached to the posterior aspect of the tumor, and sometimes the branch of the small artery enters the tumor. It must be electrocoagulated to stop bleeding. After the tumor is completely resected, the following tissue structures can be clearly seen in the surgical cavity: the humerus, the skull base, the cerebellum, the V, VI, VII, IX, X, XI brain nerves, the anterior inferior cerebellar artery, the vein and The bridge on the midline side extends the side of the brain. 6. suture the skin, close the surgery cavity After thorough rinsing, confirm that there is no foreign body or active bleeding in the operating cavity, fill the surgical cavity with sterile saline or balance solution. The dura mater was sutured along the incision line, and the incision was covered with fascia tissue. Check the bones of the squamous squamous and mastoid sides for open air chambers, seal them, and then reset the bone plates. The posterior flap of the ear was repositioned and the incision line was sutured in opposite directions. Generally, drainage is not allowed, and the back of the ear is pressure-wrapped with a thick gauze pad.

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