The Classification,surgical Approach And Therapeutic Effect Of Trigeminal Schwannoma

Objective Trigeminal schwannoma is the second most common intracranial schwannoma,the complete resection of it and the control of surgical prognosis are still difficult problems in treatment.The purpose of this study is to have a better understanding of trigeminal schwannoma in terms of tumor classification,surgical approach and prognosis.Methods In this study,the clinical manifestations,tumor characteristics,surgical methods and prognosis of 18 patients with trigeminal schwannoma diagnosed in the General Hospital and affiliated Cardiovascular and Cerebrovascular Hospital of Ningxia Medical University from 2010 to 2020 were retrospectively analyzed.According to the origin of the tumor,the tumor is divided into three types: ganglion type(type M),peripheral type(type V)and nerve root type(type P).Results The patients were ten women and eight men of mean age 43 years(range,17–64 years).There were 10(56%)and 8(44%)cases of type M and P tumor,respectively.There were 6 cases of solid tumor(33%),mostly cystic in 2 cases(11%),and cystic and solid mixed in 10 cases(56%).A total of 20 operations were performed on these 18 cases,which including 2 cases of recurrence,and 19 operations(95%)of total resection and near-total resection.Among them,subtemporal subdural transtentorial approach was used in 12 cases,of which total resection was achieved in 8 cases(67%),anterior transpetrosal-transtentorial approach was used in 4 cases,near-total resection was achieved in 3 cases(75%),retrosigmoid approach was used in 2 cases,and total resection was achieved in 1 case(50%).In this study,the subtemporal subdural transtentorial and anterior transpetrosal-transtentorial showed no significant statistical differences in tumor resection rate,postoperative symptom relief,recurrence rate and complications.In this study,2 cases of cystic tumors were not completely resected,which was more difficult to remove completely than other kinds of tumors(p=0.038<0.05).The most common symptom was facial hypesthesia in 12 cases(67%).After the operation,this symptom was improved in 6 cases(50%),and new facial hypoesthesia occurred in 4 cases.Among other nerve injuries,abducent nerve injury occurred in 7 cases,of which 2 cases were complicated with diplopia.During the average follow-up period of 38 months,recurrence occurred in 6 cases,of which 4 cases were incomplete resection,and tumor recurrence was more likely to occur after incomplete resection(p=0.037< 0.05).Most of the postoperative KPS scores of all patients were between 80 and 90,and resumed independent and social reintegration after discharge.Conclusion The main clinical manifestation of trigeminal schwannoma is facial hypoesthesia,but the relief of this clinical symptom is not obvious after operation.Preoperative classification of trigeminal schwannoma according to the origin of the tumor,which is conducive to the total resection of the tumor.For cystic trigeminal schwannoma,it is more difficult to remove completely than other tumors,and the tumor with incomplete resection is easy to recur after operation.Based on comprehensive considerations,it is recommended to use the subtemporal subdural transtentorial approach for resection of type M and some type P trigeminal schwannomas,however,due to the diversity of tumor location,specific analysis should be made for different types of tumors.