Feasibility Analysis Of Modified Distal Lateral Approach For Foramen Magnum Ventral And Jugular Foramen Tumors

Background:Tumors in the ventral region of the foramen magnum and the jugular foramen are located deep in the base of the skull,which has a narrow space and complex bony structure,making surgical resection difficult and leading to postoperative complications.The modified distal lateral suboccipital approach was used for microresection of the ventral foramen magnum and jugular foramen tumors.The differences in tumor resection degree,symptom improvement,complications and quality of life were analyzed preoperative,postoperative short-term and postoperative long-term.To investigate the feasibility of this surgical approach,and to provide clinical evidence for the treatment and prognosis of tumors in the ventral region of the foramen magnum and the jugular foramen.Methods: From August 2011 to October 2020,a total of 35 cases（single operation personner,continuous cases）of tumors in the ventral and jugular foramen of the greater occipital foramen were removed by the modified distal lateral suboccipital approach in The First Affiliated Hospital of University of Science and Technology of China.There were 14 cases of ventral tumor of the foramen magnum,including meningioma in 13 cases and schwannoma in 1 case.There were 21 cases of jugular foramen tumors,including 5 meningiomas,7 schwannomas,3 jugular bulboma,1 metastatic carcinoma,2 chondrosarcomas and 3 sublingual schwannomas.KPS（Karnofsky）score was used as the evaluation standard of preoperative,short-term and long-term postoperative quality of life.SPSS 22.0 statistical software was used to analyze the difference of symptoms and KPS score before and after surgery by Fisher’s accurate test.P<0.05 indicated that the difference was statistically significant.Results:Total resection was performed in 32 cases and subtotal resection was performed in 3 cases.A total of 31 cases were followed up,of which 4 cases were lost to follow-up.The median follow-up time was 19 months.Compared with the patients before operation,27 patients showed improvement in postoperative symptoms.A total of 26 patients still had symptoms after surgery,including 17 patients with temporary symptoms（short-term postoperative symptoms--symptoms after surgery,symptoms disappeared before discharge）,and 9 patients with persistent symptoms（long-term postoperative symptoms--symptoms to the end point of follow-up）.After surgery,symptoms such as headache,dizziness,abnormal gait and sensory impairment of limbs were relieved.In this group,a total of 14 patients（40.0%）developed temporary posterior cranial nerve disorder,among which 7 patients were new posterior cranial nerve disorder.Preoperative KPS（80 ～ 100）was 23（65.7%）,KPS（50 ～ 80）was 10（28.6%）,KPS（0 ～ 50）was 2（3.2%）.Before discharge,31 patients（88.6%）had KPS（80-100）,4 patients（11.1%）had KPS（50-80）,and 0 patients（0-50）had KPS.Among the 31 patients followed up,30 patients（96.8%）had KPS（80-100）and 1patient（3.2%）had KPS（50-80）.After a median follow-up of 1.6 years,a total of 31 patients were followed up,of which 30（96.8%）could live normally and 1（3.2%）had mild dysfunction,P < 0.05,which could be considered statistically different from that before surgery.Conclusions:The improved distal lateral approach can meet the surgical needs of the ventral foramen magnum and jugular foramen tumors.Postoperative complications were mainly cranial nerve symptoms in the posterior group.Compared with the traditional surgical method,the operation is relatively simple,the anatomical scope is smaller,and the posterior arch of atlas generally does not need to be removed,which is beneficial to avoid the occurrence of postoperative subcutaneous fluid accumulation,maintain the stability of the occipitocervical joint,and reduce neurovascular injury.