Applied Anatomical Study Of Sternocleidomastoid-mastoid Bone Flap In Jugular Foramen Tumor Surgery

Background and Objective:the local anatomical structure of jugular foramen region is complex.The contradiction between the complete resection of tumor and the protection of adjacent important structures is prominent,and the operation risk is very high.At present,the commonly used surgical methods for jugular foramen tumors often lead to tissue defects in the mastoid region and superior cervical region due to partial resection of sternocleidomastoid muscle and mastoid,which leads to complications such as effusion,collapse,deformation,cerebrospinal fluid leakage,infection and so on.Therefore,in-depth study of the anatomy of jugular foramen area,looking for a better new surgical approach and method,in order to improve the total tumor resection rate and reduce the surgical complications is an urgent task.To solve this problem in clinic,we plan to use sternocleidomastoid muscle-mastoid muscle bone flap molding method,without affecting the tumor exposure,resection on the basis of maximum preservation of its complete structure and achieve anatomical reduction.The research includes two parts:anatomy and clinic.This study intends to demonstrate the feasibility and safety of this hypothesis through autopsy.In the process of dissection,we should observe and measure the sternocleidomastoid muscle-mastoid muscle bone flap and its relationship with adjacent important anatomical structures,so as to provide reliable data support for the safe operation range of sternocleidomastoid muscle-mastoid muscle bone flap,Through repeated autopsy,we evaluated the exposure of the jugular foramen area and the important adjacent structures involved in the expansion of the surgical area,so as to further clarify the feasibility of the improved approach,and provide anatomical research basis for the second phase clinical application study.Materials and methods:Six(12 sides)adult cadaveric head specimens with neck were dissected and pretreated.Five of them were prepared according to the procedures of formalin antiseptic fixation,alcohol immersion,vascular anatomy,irrigation and pigment perfusion.One of them was washed and cryopreserved after vascular perfusion.1.Incision design:C-shaped incision behind ear,up to the highest point of auricle and down to the midpoint of anterior edge of sternocleidomastoid muscle;2.The sternocleidomastoid muscle-mastoid muscle bone flap was designed and manufactured.The nerve and distance from the mastoid tip were observed,and the risk of atrophy of the sternocleidomastoid muscle was evaluated;3.Observe the relationship between sternocleidomastoid muscle-mastoid muscle bone flap and surrounding important adjacent structures,including the position relationship between petrous segment of facial nerve,stylomastoid foramen,facial nerve trunk,vertebral artery,cervical sheath,measure the correlation distance,and evaluate the safety of sternocleidomastoid muscle-mastoid muscle bone flap manufacturing process;4.Simulate the modified approach of retaining the muscle bone flap,expose the intracranial and external orifice of jugular foramen,and observe the exposure degree of the modified approach to jugular foramen;5.The sternocleidomastoid muscle-mastoid muscle bone flap was reset to observe the degree of local tissue anatomical recovery.6.Statistical analysis of the measurement data,the measurement results of this study are based on the mean ± Standard deviation(x ± s)Cm.Results:1.The design and manufacture of sternocleidomastoid muscle-mastoid muscle bone flap:the upper line of mastoid is the upper boundary,the base of mastoid is the lower boundary,the border of sigmoid sinus is the inner boundary,and 1cm away from the posterior wall of external auditory canal.The sternocleidomastoid muscle is not broken,and it always adheres to the surface of the mastoid part of the sternocleidomastoid muscle bone flap.The sternocleidomastoid muscle-mastoid muscle bone flap was formed by milling the upper,inner,outer and part of the lower boundary with a milling cutter,and breaking and dissociating the mastoid base of the muscle bone flap from top to bottom.2.Innervation of sternocleidomastoid muscle-mastoid muscle bone flap:the motor nerve of sternocleidomastoid muscle comes from the accessory nerve,enters the carotid triangle on the deep surface behind the digastric muscle after it comes out of the jugular foramen,penetrates into the upper part of sternocleidomastoid muscle backward and outwards between the internal carotid artery and vein,and accompanies the sternocleidomastoid muscle branch of occipital artery on the deep surface of the muscle,Through the deep surface of sternocleidomastoid muscle,it continued to move outward and downward into the deep surface of trapezius muscle and dominated the two muscles.3.The modified approach with sternocleidomastoid muscle-mastoid muscle bone flap was used to fully expose the internal and external openings of jugular foramen during the simulated operation.4.The sternocleidomastoid muscle-mastoid muscle bone flap kept a stable and sufficient distance from the adjacent structures such as the vertical segment of facial nerve,extracranial segment,stylomastoid foramen,vertebral artery,cervical sheath,etc.5.The mastoid bone and sternocleidomastoid muscle were not damaged,and the local structure was completely restored after reduction.Conclusion:sternocleidomastoid muscle-mastoid muscle bone flap is feasible and safe in the operation of jugular foramen tumor1.In the process of making sternocleidomastoid muscle-mastoid muscle bone flap and exposing jugular foramen anatomically,the adjacent important structures were not damaged,so this method has high safety;2.The modified approach of sternocleidomastoid muscle-mastoid muscle bone flap can fully expose the intracranial and external orifice of jugular foramen during the operation of jugular foramen tumor;3.By making sternocleidomastoid muscle-mastoid muscle bone flap,the original anatomical structure and appearance of sternocleidomastoid muscle and mastoid can be preserved,which can effectively avoid complications such as collapse of mastoid region and upper neck,subcutaneous effusion and secondary infection caused by local tissue defect after operation.