Mclaughlin et al. reported the surgical results of 3196 trigeminal nerve root microvascular decompressions, and the complication rate of severe brain injury was 0.87% before the 1990s and still 0.45% after the 1990s. Hanakita et al. reported 9 serious surgical complications in 278 cases of neurogenic microvascular decompression, 7 of which were due to trigeminal root microvascular decompression, and 2 of which died.
Schmidek
et al. surveyed 49 hospitals performing trigeminal root microvascular decompression and found that 14 hospitals had experienced surgical deaths, with a maximum mortality rate of 7%, not least of which were performed by outstanding neurosurgeons. Among the causes of death, the most common cause was cerebellar and brainstem necrosis after severing the rock vein, followed by intracerebellar hemorrhage or subdural hematoma in the posterior cranial fossa. Our experience with more than 5,000 apparent microvascular decompression cases has resulted in a mortality rate of 0.2%. The incidence of short-term complications is about 3%, mainly cerebrospinal fluid leakage, hearing loss, diplopia, brainstem and intracranial infections, etc. 1, postoperative intracranial infection The operation is aseptic surgery, and strict aseptic operation is the most effective measure to prevent postoperative infection. Patients with clear infectious lesions in the body before surgery should postpone the operation and clear the existing infection first. Once it is clear that there is bacterial infection in the cerebrospinal fluid by lumbar puncture, effective antimicrobial agents should be selected according to clinical judgment and bacteriological examination, and effective doses of treatment should be used. 2, cerebrospinal fluid leakage Cerebrospinal fluid leakage is caused by improper closure of the incision. The dura mater of this surgical approach is not easily sutured tightly, and if the mastoid airspace is open, the airspace must be completely closed with bone wax. Cerebrospinal fluid leakage from the incision is usually due to poor subcutaneous suturing, which can be stopped by adding 1-2 stitches. If there is cerebrospinal fluid leakage through the mastoid trachea-eustachian tube, it can lead to severe hypocranial pressure and headache, and the incision needs to be reopened, the dural breach repaired, and the mastoid trachea closed. 3. Postoperative intracranial hematoma Postoperative subdural or intracerebellar hematoma is a serious complication, although the incidence is less than 0.5%.
Although the incidence is less than 0.5%, it can often be fatal. Improper intraoperative treatment of the rock vein is the main cause of hematoma. The rock vein is an important drainage vein for the cerebellum and lateral brainstem, and in most patients it can be compensated by other drainage veins after dissection; however, in some patients with particularly large rock veins, dissection may lead to cerebellar bruising infarction and intracerebellar hematoma. Failure to properly treat the severed end of the rock vein and rupture and bleed when the venous sinus pressure is elevated by actions such as extubation, coughing, and breath-holding is a common cause of subdural hematomas. Patients with impaired coagulation mechanisms can also lead to postoperative intracranial hematomas, and preoperative examination must exclude such patients. Management of the rock vein is the most important measure to prevent intracranial hematoma. If the rock vein is long enough to be free without obstructing the exposure of the trigeminal nerve, it should not be cut off easily. If one can be cut to meet the requirement of exposure, do not cut it all together. The patient’s consciousness, blood pressure, pulse and other signs should be closely monitored in the first 24 hours after surgery. If the patient should be awake after stopping anesthesia but is not awake, or if he/she becomes unconscious again after being awake from anesthesia and has unstable blood pressure, a CT scan of the posterior cranial recess should be performed immediately to detect the intracranial hematoma in time. Patients with confirmed posterior cranial sulcus hematoma should be operated again immediately to remove the hematoma and stop the bleeding completely, without any luck. 4.Brain stem and cranial nerve injury Cranial nerve injury is mainly related to inexperienced surgery and operation error. The most frequent injury is the pulvinar nerve, when dissecting the free trigeminal nerve root, we should pay attention to identify and protect the pulvinar nerve located under the cerebellar curtain margin. Brainstem injury is mostly caused by injury to the blood vessels supplying the brainstem, therefore, when freeing the blood vessels around the nerve roots, gentle movements should be made and the tiny branches entering the brainstem should not be stretched. Skilled microneurosurgical techniques and proficiency in the necessary anatomical knowledge can reduce the risk of microvascular decompression.