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Abstract Introduction The surgical management that achieves minimal morbidity and mortality for patients with glomus and non-glomus tumors involving the jugular foramen (JF) region requires a comprehensive understanding of the complex anatomy, anatomic variability, and pathological anatomy of this region. Objective The aim of this study is to propose a rational guideline to expose and preserve the lower cranial nerves (CNs) in the lateral approach of the JF. Methods The technique utilized is the gross and microdissection of 4 fixed cadaveric heads to revise the JF's surgical anatomy and high part of the carotid sheath compared with surgical cases to understand and preserve the integrity of lower CNs. The method involves radical mastoidectomy, microdissection of the JF, facial nerve, and high neck just below the carotid canal and the JF. The CNs IX, X, XI, and XII are microscopically dissected and kept in sight up to the JF. Results This study realized well the surgical and applied anatomy of the lower CNs with relation to the facial nerve and JF. Conclusions The JF anatomy is complicated, and the key to safely operate on it and preserving the lower CNs is to find the posterior belly of the digastric muscle, to skeletonize the facial nerve, to remove the mastoid tip preserving the stylomastoid foramen, to skeletonize the sigmoid sinus and posterior fossa dura not only anterior but also posteroinferior to reach and drill the jugular tubercle.
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Objective To investigate the difference in normal tissue complication probability (NTCP) of lower cranial nerves (LCNs) between target volumes recommended by Radiation Therapy Oncology Group (RTOG) and China in intensity-modulated radiotherapy (IMRT) for T1-2 nasopharyngeal carcinoma (NPC),and to provide the evidence of dose-volume effect for the protection of LCNs in IMRT for NPC.Methods A total of 20 patients with T1-2 NPC who were treated from 2013 to 2015 were enrolled,and LCNs were delineated on CT images.Target volume delineation and treatment plan designing were performed according to the method recommended by RTOG0225 (RTOG target volume delineation method) or the Chinese Working Committee for Clinical Staging of NPC in 2010 (Chinese target volume delineation method),and the differences in the dose to LCNs and NTCP were calculated.Results In the RTOG and Chinese methods for target volume delineation,Dmax to the left and right LCNs was 7 450±273 cGy/7294±309 cGy and 7 361± 160 cGy/7 190±395 cGy,respectively (P=0.018 and 0.042),Dmean was 6735±285 cGy/6 660±333 cGy and 6 446±429 cGy/6 299±467 cGy,respectively (both P=0.000),and the NTCP was 60％±10％/57％±13％ and 51％±15％/45％±17％,respectively (both P=0.000).Conclusions It is feasible to precisely delineate target volume with the LCNs as a routine OAR and predict NTCP in IMRT for T1-2 NPC.The NTCP of the LCNs is closely associated with target volume dose and irradiated volume.The dose to the LCNs and NTCP determined by the Chinese target volume delineation method are significantly lower than those determined by the RTOG method.
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Objective:To compare 3D TOF-SPGR with 3D FIESTA in the display of lower cranial nerves.Methods:3D FIESTA and 3D TOF-SPGR were applied to 5 volunteers and 8 patients whose chief complaints were vertigo and tinnitus.Results:The rate of visualization of these lower cranial nerves with 3D TOF-SPGR and 3D FIESTA sequences,respectively,were as follows:nerve Ⅸ～Ⅺ complex(65% and 100%);nerve Ⅶ(12% and 81%).Statistical significant differences existed between 3D TOF-SPGR and 3D FIESTA sequences(P