Anatomical and prospective clinical study of variant distribution of the glossopharyngeal nerve | ||||
| The Egyptian Journal of Anatomy | ||||
| Article 10, Volume 40, Issue 1, January 2017, Page 142-154 PDF (6.14 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejana.2017.5719 | ||||
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| Authors | ||||
| Madiha Awad1; Abeer Ahmed2; Hisham el badan3 | ||||
| 1Department of Anatomy and Embryology, Faculty of Medicine, Alexandria University, Alexandria, Egypt | ||||
| 2Department of Anatomy and Embryology, Faculty of Medicine, Alexandria University, Alexandria, Egypt | ||||
| 3Department of otorhinolaryngology, Faculty of Medicine, Alexandria University, Alexandria, Egypt | ||||
| Abstract | ||||
| Background: Removal of lesions involving the jugular foramen region requires detailed knowledge of the anatomy and anatomical landmarks of the related area, especially the lower cranial nerves. The glossopharyngeal nerve (GPhN) courses along the uppermost part of the jugular foramen and is well hidden in the deep layers of the neck, making this nerve is the most difficult one to identify during surgery. The glossopharyngeal nerve can be compromised iatrogenically during the surgical procedures. Aim of the work: Is to investigate the topography and branching pattern of the GPhN and to define the important landmarks that can help to identify this nerve during surgery. It also designed to evaluate the post-tonsillectomy pain and the role of the different patterns of distribution of the glossopharyngeal nerve branches within the tonsillar fossa in the perception of pain in the postoperative period. Materials and Methods: Thirty glossopharyngeal nerves in fifteen cadaveric necks were dissected. The anatomic relation between the GPhN and the nearby structures, distribution and branching pattern of the GPhN were studied. Regarding the GPhN in the tonsilar fossa two anatomic distances were measured: A) distance from the posterosuperior tonsillar fossa to the main trunk of the GPhN and B) distance from the posteroinferior tonsillar fossa to the closest lingual branch of the glossopharyngeal nerve (LBG). The level of the post-operative pain was estimated in 70 patients at one and three hours, and one week aftertonsillectomy by numeric pain intensity scale Technique of anesthesia was similar for all patients. At the end of the procedure, a 1 ml mixture of Xylocain- Marcaine solution was infiltrated in the lower tonsillar pole on both sides. Results: The GPhN can be divided into three portions: cisternal, jugular foramen and extracranial part. Tough dural septum separates the jugular part of the GPhN from both vagus and accessory nerves in 20% of the cadaveric specimens. The GPhN was anastomosed with the hypoglossal nerve in 40% and with the lingual nerve in 50%. The lingual branch of the glossopharygeal nerve (LBG) entered the tongue obliquely bifurcated into medial and lateral primary branches, with the former innervating most of the circumvallate papillae. In 30% the medial branches of LBG extended anteriorly beyond the sulcus terminalis and the circumvallate papillae. Tonsillar branches were originating from the GPhN in 60% and from the LBG in 40%. The mean distance from the posterosuperior tonsillar fossa and the main trunk of the glossopharyngeal nerve was 9.3 mm, and the mean distance from the posteroinferior tonsillar fossa and the closest lingual branch of the glossopharyngeal nerve was6.7 mm. Results of the clinical study showed statistically significant lower pain scores (according to VAS score) in the recovery room, 1and 3hours after surgery in the group that received local anesthetic infiltration compared with the other group that didn’t receive any local anesthetic infiltration. Also 1 week postoperatively there was again a statistically significant lower pain scores in the group that received local anesthetic infiltration. Conclusions: Accurate identification and exposure of the GPhN allow for its preservation during surgical resection of any pathological entities along its course. The results of the anatomical dissection study done points to the crucial role the glossopharyngeal nerve branching patterns in determining the level of the postoperative pain perception after tonsillectomy operation. | ||||
| Keywords | ||||
| Glossopharyngeal nerve; Distribution; Anatomical; Prospective | ||||
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