Fenestration and Bifurcation of the Internal Jugular Vein; Surprises During Head and Neck Surgery

Case Report Iranian Journal of Otorhinolaryngology, Vol.37(2), Serial No.139, Mar-2025 Fenestration and Bifurcation of the Internal Jugular Vein; Surprises During Head and Neck Surgery Vibha Singh1, *Arijit Jotdar1, Annanya Soni1, Rudra Prakash1, Kushal Singh2 Abstract Introduction: The internal jugular vein (IJV) is one of the major vessels in the neck and serves as an important landmark for surgeons during head and neck surgery. Anomalies of the IJV are rare and seldom encountered by the surgeons. However, a comprehensive knowledge of these variations is essential for better surgical dissection and to prevent intra-operative mishaps. The variations can be in the forms of bifurcation, trifurcation, duplication, fenestration and posterior tributaries of the IJV. Here we describe three cases of bifurcation and fenestration of the IJV that we encountered in our surgical practice. Case Report: In the first patient, we found an empty fenestration of the right internal jugular vein during a selective neck dissection for tongue carcinoma. The spinal accessory nerve was passing lateral to the IJV above the level of the fenestration. The second patient was operated for a left vagal schwannoma in the neck. During the surgery, we found a bifurcation of the left IJV, and the two tributaries fused just above the left omohyoid muscle. The third patient, a sixty-year-old lady also had a bifurcation of the left IJV. It was found during a modified radical neck dissection for carcinoma ex pleomorphic adenoma of the left parotid gland. Conclusion: An in-depth knowledge of the anomalies of the internal jugular vein and meticulous evaluation of the pre-operative imaging may help the surgeons in preventing any intra-operative catastrophe during head and neck surgery. Keywords: Internal jugular vein, Fenestration, Bifurcation, Anatomical variation, Spinal accessory nerve Received date: 21 Oct 2024 Accepted date: 26 Jan 2025 *Please cite this article; Singh V, Jotdar A, Soni A, Prakash R, Singh K. Fenestration and Bifurcation of the Internal Jugular Vein; Surprises During Head and Neck Surgery. Iran J Otorhinolaryngol. 2025:37(2):99-103. Doi: 10.22038/ijorl.2025.83514.3810 1Department of Otorhinolaryngology All India Institute of Medical Sciences, Raebareli, Uttar Pradesh, India. Department of Radiodiagnosis All India Institute of Medical Sciences, Raebareli, Uttar Pradesh, India. *Corresponding author: Department of Otorhinolaryngology All India Institute of Medical Sciences, Raebareli, Uttar Pradesh, India. E-mail: 2 Copyright©2025 Mashhad University of Medical Sciences. This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 International License https://creativecommons.org/licenses/by-nc/4.0//deed.en 99 Singh V, et al Introduction The internal jugular vein (IJV) is one of the most significant vascular landmarks for surgeons during head and neck surgery. As a continuation of the sigmoid sinus, this major vessel enters the neck through the jugular foramen and drains into the Subclavian vein to form the Brachiocephalic vein (1). It is an important landmark for the Spinal accessory nerve (SAN), Vagus nerve, Carotid artery and cervical lymph nodes (2). This large calibre vessel also serves as the route for central venous access and is hence important for anaesthetists and intensivists. Anatomical variations of the IJV are uncommon and are mostly reported by anaesthetists during imaging for central venous access (1). The Internal jugular vein receives both major and minor tributaries in the neck. Any major surgery in the neck involves the handling of this vessel. Therefore, an in-depth knowledge of its normal anatomy and associated variations is essential to avoid any untoward incident during surgical dissection. Any such anatomical variation of the IJV and adjacent vital structures especially the spinal accessory nerve can be diagnosed preoperatively by meticulous examination of the imaging studies including CT scans and MRI scans, which are routinely performed for any head and neck surgery. However, due to its rarity, the variations of the IJV are sometimes overlooked and remain undetected preoperatively. Case Report Case 1: A 48-year-old lady presented in the department of Otorhinolaryngology with a nonhealing ulcer over the right lateral border of the tongue. Biopsy from the lesion yielded a welldifferentiated squamous cell carcinoma. The patient was staged as cT2N1M0 after all necessary investigations. She underwent Wide local excision with selective neck dissection (IIV) with primary repair. During neck dissection, we found that the right internal jugular vein split into two branches just below the level of the hyoid bone. Both the branches fused again to form a single trunk of the IJV at the level of the cricoid cartilage. No significant neurovascular structure was found passing between the branches making it an empty fenestration (Figure 1). The spinal accessory nerve was found separately above the level of fenestration. Fibrofatty tissue was gently dissected from both the branches and neck dissection was completed. The intraoperative period was uneventful with no injury to the internal jugular vein and spinal accessory nerve. Postoperatively virtual CT scan was reviewed which confirmed an empty fenestration of the right internal jugular vein. Fig 1: A. Empty fenestration of the right internal jugular vein (white arrow). The spinal accessory nerve is passing lateral to the IJV above the level of the fenestration (black arrow). The sternocleidomastoid (SCM) and digastric (D) muscles are also seen in the surgical field. B. Reconstructed virtual CT scan of the patient showing the empty fenestration of the right internal jugular vein (yellow arrow). Case 2: A 19-year-old gentleman presented with a gradually progressive swelling over the left side of the neck for the last one year. Fine needle aspiration cytology pointed towards a spindle cell neoplasm. MRI scan was suggestive of a vagal schwannoma. The patient was taken up for trans-cervical excision of vagal schwannoma under general anaesthesia. Intraoperatively, the left common carotid artery and the left internal jugular vein were found to be pushed medially by the tumour. Another major vessel was found to be running vertically over the tumour, which could be traced back up to the skull base. On incising the carotid sheath, we found a bifurcation of the left internal jugular vein just above the level of the cricoid cartilage (Figure 2). The tumour was carefully separated from the internal jugular vein, thereby preserving both of its branches. 100 Iranian Journal of Otorhinolaryngology, Vol.37(2), Serial No.139, Mar-2025 Fenestration and Bifurcation of the IJV (Figure 3). This was further established by a careful examination of the virtual CT scan. Fig 2: Bifurcation of the left internal jugular vein (white arrow). Both the tributaries fused above the level of the omohyoid forming the main trunk of (...truncated)