Role of occipital attachment point of obliquus capitis superior/rectus capitis posterior major in microsurgery through retrosigmoid approach for patients with cerebellopontine angle lesons

ZUO Da-hui; JIANG Tai-peng; HE Jia-bin; LIN Heng-zhou; WANG Jian-zhong; JI Tao; GONG Wei-zhao

doi:10.13798/j.issn.1009-153X.2023.10.003

Abstract：Objective To investigate the clinical significance of the occipital attachment point of the obliquus capitis superior(OCS)/rectus capitis posterior major(RCPM)as a marker of the lower boundary of the bone window in micorsurgery through retrosigmoid approach for patients with cerebellopontine angle(CPA)lesions.Methods From January 2018 to November 2021,81 patients with CPA lesions were prospectively collected.The transverse sinus,the attachment point of OCS/RCPM at occipital bone,vertebral artery or peripheral venous plexus were located and the corresponding distances were measured according to preoperative MRI.The attachment point of OCS/RCPM at occipital bone was used as the reference for the lower boundary of bone window.During the surgery,the attachment point of the OCS/RCPM to the occipital bone as a reference for the lower boundary of the bone window.Results Preoperative MRI showed that the distance between the lower boundary of the transverse sinus and the attachment point of the OCS/RCPM at the occipital bone was 26.1～40.7 mm,with an average of(33.4±3.5)mm;the distance between the attachment point of the OCS/RCPM at the occipital bone and the vertebral artery or peripheral venous plexus was 11.3～27.2 mm,with an average of(18.6±3.6)mm.During the operation,the distance between the upper and lower boundaries of the bone window was(36.8±5.2)mm(the upper boundary was the lower margin of the transverse sinus),and the lesions were all exposed satisfactorily,and no vertebral artery/peripheral venous plexus was exposed or injured.Total tumor resection was achieved in 46 patients with acoustic neuromas,13 patients with meningiomas,and 7 patients with cavernous hemangiomas.Nearly total tumor resection was performed in 15 patients with acoustic neuromas due to the close relationship between the tumor and the facial nerve.CT/MRI reexamination 1 week to 1 year after surgery showed no skull defect and no subcutaneous fluid.Conclusions During the surgery through retrosigmoid approach for patients with CPA lesions,using the attachment point of the OCS/RCPM at the occipital bone as the marker of the lower boundary of the bone window is beneficial to the safe exposure of the operative field and has important guiding significance for the surgical process.