Routine removal of the carotid sheath as part of neck dissection is unnecessary if grossly uninvolved as seen intra-operatively

Carotid Sheath Dissection and Histopathology During Neck Dissection in Head and Neck Carcinomas

To investigate the carotid sheath in neck dissection (ND) specimens histopathologically in patients with head and neck carcinomas who had no evidence of previous neck surgery or direct involvement of the carotid sheath in their pre- or intra-operative evaluations. In this study, carotid sheath (CS) specimens of 40 patients with head and neck carcinomas (HNCA) who, depending on the condition of the primary tumor, required unilateral or bilateral elective or therapeutic selective neck dissection were histopathologically investigated by an expert head and neck pathologist to find any lymphoid or thyroid like tissue or tumor cells infiltration. A total of 50 carotid sheath (CS) specimens were investigated. None of the samples showed any evidence of tumor infiltration or accumulation of lymphatic tissue. We conclude that in patients with no histopathologic involvement of the carotid sheath in pre-operative or intra-operative tumor invasion, it is not necessary to remove CS in routine neck dissection.

The carotid sheath: Anatomy and clinical considerations

Objectives

The distinctive bilateral carotid sheaths (CS) reside in the neck region and form part of the deep cervical fasciae. Aspects of the CS anatomy are controversial, most notably its specific attachment sites and fascial makeup, which are key determinants for the spread of tumours and infections and surgical planning. This review aimed to organise the pertinent aspects relating to CS anatomy and pathology, explore their clinical relevance and highlight areas of disagreement in the literature.

Methods

A narrative review identified key papers relating to CS anatomy, histology, embryology, pathology and clinical and surgical significance using PubMed and Google Scholar. This was supported by a systematic review focused on the fascia forming the CS which was conducted using PubMed, Web of Science and Core Collection which yielded 22 papers.

Results

and Discussion: The CS surrounds the internal carotid artery, internal jugular vein, cranial nerves IX - XII, lymph nodes and nervous plexuses as they course from the jugular foramen superiorly down along into the mediastinum inferiorly. There are contradicting descriptions regarding the CS attachments at the extracranial skull base and within the mediastinum. Author descriptions of the CS fasciae are complex, varied and incongruent. Pathologies affecting the CS include malignancies of the nerves, vascular lesions and utilisation of the CS space as a corridor for the spread of deep neck infections.

Conclusion

This paper collates and presents pertinent anatomical and clinical aspects regarding the CS. A proper knowledge of the CS anatomy and structural relationships will optimise surgical approaches and orientation when operating within the region.

Histological Assessment of the Carotid Sheath in Patients With Oral Squamous Cell Carcinoma

PURPOSE

During surgical management of the neck using various types of neck dissection, the carotid sheath is removed, in particular, the part adjacent to the jugular lymph node chain, with the intention of preventing recurrence from the lymphatics present within it. The role of the carotid sheath as a potential origin for nodal recurrence has not been proved thus far. Working in a tissue plane between the carotid sheath and the neurovascular structures of the neck can lead to a greater chance of damage to these structures. Also, the carotid sheath is a strong fibroelastic tissue barrier that shields the internal jugular vein and carotid artery from saliva and local infection during the postoperative period. Thus, this study investigated the histopathology of the carotid sheath in patients with oral squamous cell carcinoma (OSCC) and assessed the pathologic infiltration of the carotid sheath when grossly uninvolved.

PATIENTS AND METHODS

Pathologic infiltration and histopathologic characteristics of the entire length of the carotid sheath were assessed in 30 biopsy-proved cases of OSCC; these patients underwent surgical excision of the lesion in addition to neck dissection from 2013 to 2015 in the craniofacial unit of the authors' institution.

RESULTS

The carotid sheath consisted of fibrofatty tissue and interspersed nerve bundles. Neutrophilic infiltration and dilated lymphatic channels were seen in all 30 cases. Miniature lymph nodes adherent to the carotid sheath were seen in 5 cases and some lymphoid aggregates were seen in 15 cases. The carotid sheath in all 30 cases (metastatic and nonmetastatic) was free from tumor deposit and lymphatic tumor emboli, which are indicators of tumor cell infiltration.

CONCLUSION

Indicators of tumor cell infiltration were not found in any of the 30 cases. The result did not vary with the age or gender of the patient, tumor size, location, staging or grading of the tumor, or even when there were metastatic lymph nodes in the gross specimen. Hence, the role of the carotid sheath as a potential origin for nodal recurrence is questionable and its removal needs reconsideration.