Читать книгу Pearls and Pitfalls in Head and Neck Surgery - Группа авторов - Страница 19
ОглавлениеThyroid and Parathyroid Glands
Cernea CR, Dias FL, Fliss D, Lima RA, Myers EN, Wei WI (eds): Pearls and Pitfalls in Head and Neck Surgery. Basel, Karger, 2012, pp 26–27
DOI: 10.1159/000338004
1.13 Central Compartment Neck Dissection: Surgical Tips
Dan M. Flissa Ralph P. Tufanob
aDepartment of Otolaryngology- Head and Neck Surgery and Maxillofacial Surgery, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; bDepartment of Otolaryngology- Head and Neck Surgery, Johns Hopkins University, Baltimore, Md., USA
P E A R L S
• An informed discussion with the patient on recurrent laryngeal nerve (RLN) paralysis and hypoparathyroidism is essential.
• Always perform a preoperative laryngoscopy and document vocal fold mobility.
• Identify the RLN and trace out its full course in the central neck.
• The right RLN runs obliquely and more anterior than the left RLN, making it necessary to transpose it to allow for removal of lymph nodes posterior and lateral to it.
• The use of intraoperative RLN monitoring may help in the identification and preservation of all motor nerve branches, especially in revision cases.
• Care should be taken to preserve the parathyroid glands on a vascularized pedicle if possible, especially the superior ones.
• Any suspicion of a devascularized parathyroid gland should be sampled to confirm parathyroid tissue by frozen section and autotransplanted into the adjacent sternocleidomastoid or sternohyoid muscle.
P I T F A L L S
• Failure to dissect all lymph node-bearing tissue in the paratracheal compartment including the lymph nodes posterior to the common carotid and the area deep to the RLN, especially on the right.
• Failure to resect the Delphian/prelaryngeal lymph nodes.
• Tracheal, esophageal, or vascular injury.
Introduction
The central compartment of the neck is defined by the hyoid bone superiorly, innominate artery inferiorly, common carotid arteries laterally, trachea medially, strap muscles anteriorly, and prevertebral fascia posteriorly. The central compartment of the neck includes the prelaryngeal, pretracheal, and paratracheal lymph nodes (level VI), as well as the superior mediastinal lymph nodes above the innominate artery (level VII). A central compartment neck dissection (CCND) for thyroid cancer must include the prelaryngeal, pretracheal, and at least one paratracheal lymph node basin [1].
Practical Tips
Management of the RLN. The RLN needs to be clearly identified in all cases. The anatomical landmarks for doing so are the inferior thyroid artery, ligament of Berry, and tracheoesophageal groove. Skeletonization of the RLN in its entirety is important since transferring the specimen from a lateral to a medial position might necessitate elevation of the nerve. The best way to protect the nerve is to dissect it inferiorly and underneath the common carotid artery following the thyroidectomy. The right RLN must be circumferentially dissected to allow removal of lymph nodes deep to it [2]. This is best accomplished with a fine tip dissector and scalpel, and by avoiding the use of a nerve hook in order to minimize trauma.
Management of the Parathyroid Glands. The preservation of the parathyroid glands together with their blood supply is ideal, but not always possible. The inferior parathyroid glands are the ones most at risk during a CCND and they may have to be autotransplanted because it is often difficult to preserve their blood supply and effectively remove all the paratracheal nodes. Great care should be taken to preserve the superior parathyroid glands at the time of a thyroidectomy. There should be a high priority for autotransplantation of parathyroid glands that have questionable viability. A frozen section evaluation of approximately 10% of the 'parathyroid gland' to be autotransplanted should be performed in order to confirm that the specimen is parathyroid tissue. Once confirmed, the remainder of the parathyroid gland should be minced into 1-mm pieces and placed in a dry muscle pocket created within the sternohyoid or sternocleidomastoid muscle [3]. This site should be marked with nonabsorbable sutures or vascular clips.
Modifications for Reoperations. A preoperative laryngoscopy should be routinely performed in order to assess the function of both vocal cords. The original incision for a thyroidectomy may be used for a CCND. The sternothyroid muscle can be divided in order to achieve better exposure. A posterolateral approach may be used if the surgical field is adhesive and fibrotic. The RLN should be visualized in an area that has not been dissected in the previous operation, and then followed along its entire course. The risk of hypocalcemia is high, especially in reoperations [4, 5]. Identification of the parathyroid glands might be difficult in a densely fibrotic area, but every effort should nevertheless be made to preserve them. The use of a nerve monitoring system during reoperations may be helpful. While it is unlikely to occur during primary surgery, any tracheal or esophageal injury during a CCND must be promptly detected intraoperatively. This type of injury requires an attempt at primary closure. A sternothyroid muscle rotation flap can be used to carefully patch the tracheotomy, or, alternatively, it can be used to reinforce the tracheal or esophageal closure. Tumor recurrence after a previous CCND is most often the result of incomplete initial resection of gross nodal disease [6]. It is important to bear in mind that there are lymph nodes posterior to the RLN and the common carotid artery that need to be addressed during the dissection.
Conclusion
Detailed anatomical knoWIedge of the central compartment of the neck is extremely important in order to perform an effective and safe CCND when indicated.
References
1 American Thyroid Association Surgery Working Group, American Association of Endocrine Surgeons, American Academy of Otolaryngology-Head and Neck Surgery, American Head and Neck Society, Carty SE, Cooper DS, Doherty GM, Duh QY, Kloos RT, Mandel SJ, Randolph GW, Stack BC Jr, Steward DL, Terris DJ, Thompson GB, Tufano RP, Tuttle RM, Udelsman R: Consensus statement on the terminology and classification of central neck dissection for thyroid cancer. Thyroid 2009;19:1153–1158.
2 Pai SI, Tufano RP: Central compartment neck dissection for thyroid cancer. Technical considerations. ORL J Otorhinolaryngol Relat Spec 2008;70:292–297.
3 Randolph GW: Surgery of the Thyroid and Parathyroid Glands. Philadelphia, Saunders, 2003.
4 Khafif A, Ben-Yosef R, Abergel A, Kesler A, Landsberg R, Fliss DM: Elective paratracheal neck dissection for lateral metastases from papillary carcinoma of the thyroid: is it indicated? Head Neck 2008;30:306–310.
5 Kim MK, Mandel SH, Baloch Z, Livolsi VA, Langer JE, Didonato L, Fish S, Weber RS: Morbidity following central compartment reoperation for recurrent of persistent thyroid cancer. Arch Otolaryngol Head Neck Surg 2004;130:1214–1216.
6 Bardet S, Malville E, Rame JP, Babin E, Samama G, De Raucourt D, Michels JJ, Reznik Y, Henry-Amar M: Macroscopic lymphnode involvement and neck dissection predict lymph-node recurrence in papillary thyroid carcinoma. Eur J Endocrinol 2008;158:551–560.
Dan M. Fliss, MD
Professor and Chairman
Department Otolaryngology,
Head and Neck Surgery and
Maxillofacial Surgery
Tel Aviv Sourasky Medical Center
6 Weizmann St.
Tel Aviv 64239 (Israel)
E-Mail fliss@tasmc.health.gov.il
