The larynx is a highly vascularized organ supplied by the superior and inferior laryngeal arteries. Both microphonosurgery and external laryngeal surgery require excellent hemostasis. Topical agents including adrenalin and fibrin-based products as well as surgical instrumentation, such as coagulation devices or in some cases embolization, are in the surgeon’s armamentarium and facilitate efficient and successful surgery.
Key learning points
At the end of this article, the reader will:
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Have a good understanding of the major vessels supplying the larynx.
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Appreciate why hemostasis is critical in laryngeal surgery.
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Be able to describe methods of applying topical agents to the larynx.
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Be able to discuss the properties and appropriate use of various surgical tools used in hemostasis.
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Understand the indications for preoperative embolization.
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Review the general guidelines on perioperative management of anticoagulant medication.
Introduction
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Types of laryngeal surgery
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Endoscopic, external, and combined approach
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Endoscopic approach
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Hemostasis critical to microsurgery of superficial lamina propria and postoperative voice outcomes
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External approach
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May require control of the following vessels
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Internal carotid artery
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External carotid artery (ECA)
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Common carotid artery
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Internal jugular vein (IJV)
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Laryngeal surgery has continued to evolve over the last century with a multitude of endoscopic and external procedures commonly performed. In recent times technology has allowed an increasing number of procedures to be performed under local anesthesia. An improved understanding of the phonatory mechanism and microstructure of the vocal fold has also led to an increased awareness of the important role the superficial lamina propria plays in phonation. Consequently, protection of this layer is paramount in laryngeal microsurgery; hemostasis is essential for visualization and ensuring protection of the delicate microstructure.
External laryngeal procedures, such as total laryngectomy, often in combination with neck dissection may result in exposure, resection, or injury to major vessels. When possible this should be planned before surgery with the availability of blood products anticipated in some situations.
Introduction
- •
Types of laryngeal surgery
- ○
Endoscopic, external, and combined approach
- ○
- •
Endoscopic approach
- ○
Hemostasis critical to microsurgery of superficial lamina propria and postoperative voice outcomes
- ○
- •
External approach
- ○
May require control of the following vessels
- ▪
Internal carotid artery
- ▪
External carotid artery (ECA)
- ▪
Common carotid artery
- ▪
Internal jugular vein (IJV)
- ▪
- ○
Laryngeal surgery has continued to evolve over the last century with a multitude of endoscopic and external procedures commonly performed. In recent times technology has allowed an increasing number of procedures to be performed under local anesthesia. An improved understanding of the phonatory mechanism and microstructure of the vocal fold has also led to an increased awareness of the important role the superficial lamina propria plays in phonation. Consequently, protection of this layer is paramount in laryngeal microsurgery; hemostasis is essential for visualization and ensuring protection of the delicate microstructure.
External laryngeal procedures, such as total laryngectomy, often in combination with neck dissection may result in exposure, resection, or injury to major vessels. When possible this should be planned before surgery with the availability of blood products anticipated in some situations.
Vascular supply of larynx
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Superior and inferior laryngeal arteries supply most of the larynx.
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Superior laryngeal artery (SLA): branch of the superior thyroid artery from the ECA
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Inferior laryngeal artery (ILA): branch of the inferior thyroid artery arising from the thyrocervical trunk of the subclavian artery
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SLA supplies most of tissues of larynx from epiglottis down to the vocal folds.
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ILA supplies the region around the cricothyroid and posterior cricoarytenoid.
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There are multiple anastomoses between the ipsilateral and contralateral laryngeal arteries.
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Superior and inferior laryngeal veins run parallel to the arteries and drain into the superior and inferior thyroid veins.
The blood supply of the larynx is derived mainly from the SLA and ILA. The SLA branches off the superior thyroid artery as the latter passes down towards the upper pole of the thyroid gland. Rarely SLA may arise directly from the ECA. The SLA courses towards the larynx, with the internal branch of the superior laryngeal nerve lying above it. It enters the larynx by penetrating the thyrohyoid membrane and divides into several branches that supply the larynx from the tip of the epiglottis down to the inferior margin of thyroarytenoid. It anastomoses with the contralateral SLA as well as the ILA.
The ILA is smaller than the SLA, supplies the area around the cricothyroid, and has a small branch travelling back to the region of the posterior cricoarytenoid muscle. It is a branch of the inferior thyroid artery that arises from the thyrocervical trunk of the subclavian artery. It ascends on the trachea with the recurrent laryngeal nerve entering the larynx at the lower border of the inferior constrictor, just behind the cricothyroid joint. It also anastomoses with the contralateral ILA as well as the SLA.
There is also a cricothyroid artery that arises from the superior thyroid artery and follows a variable course either superficial or deep to the sternothyroid muscle anastomosing with the ILA.
Venous return from the larynx occurs via the superior and inferior laryngeal veins, which run parallel to the SLA and ILA. They drain into the superior and inferior thyroid veins, respectively. The superior thyroid vein then drains into the IJV and the inferior thyroid vein into the left brachiocephalic vein.
Laryngeal procedures
In general, hemostasis in laryngeal surgery can be achieved is straightforward to control, particularly when it is anticipated by the Surgeon with good anatomical knowledge and correct instrumentation available ( Fig. 1 ). It is preferable to avoid blood in the airway as it may lead to airway compromise, distal migration for example, clot, alveolar irritation and coughing and laryngospasm during emergence from anesthesia. The risk of hemorrhage may be predicted by assessing the pathology being treated, the method of surgery, medication use and level of anesthesia.
Endoscopic approach
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Benign lesions (excision or ablation)
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Cysts, polyps, nodules, papillomas, fibrous masses, polypoid corditis (Reinke edema), vocal fold granuloma, sulcus vocalis
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Injection laryngoplasty
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Premalignant or malignant lesions (excision? biopsy?)
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Leukoplakia
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Partial laryngectomy
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Airway stenosis: supraglottic, glottic, subglottic, tracheal (airway reconstruction?)
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External approach
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Laryngeal framework surgery, thyroid surgery, laryngocele, laryngeal fracture, partial and total laryngectomy
Laryngeal surgery may be performed endoscopically, externally, or combined external and endoscopic approaches. The advent of robotic surgery with microinstrumentation and laser surgery may well alter the breadth of procedures conducted endoscopically in the future. Increasingly many procedures are now being performed under local anaesthesia, which presents new challenges to the surgeon and can make bleeding more intrusive in awake patients and challenging to control because of limited access, patient discomfort or intolerance, and labile blood pressures.
Microlaryngeal surgery uses a magnified view via an operating microscope to optimize preservation of delicate vocal fold microstructure. Because the field of view is narrow, just a few milliliters of blood will obscure anatomic detail and limit safe surgery. Particularly when resecting or dissecting the epithelium or superficial lamina propria zones, visualization is critical. Even minute amounts of blood can impair visualization and adversely affect surgical outcomes. If bleeding occurs, then dissection should be temporarily ceased and the bleeding controlled before proceeding. Not only does this improve visualization but it also prevents dispersion of blood (and its subsequent inflammatory hemolytic cascade) within the pliable vibratory tissues, which translates to better functional preservation and improved vocal outcomes. Vocal fold hemorrhage results in a stiff, bulky vocal fold that does not vibrate because of excess fluid within the superficial compartment and, if a large volume is present, even a convexity to the vocal fold that may result in early contact and glottal gapping. Marked dysphonia to complete aphonia may ensue, and recovery of normal mucosal wave and contact can take weeks as proteolysis occurs and vocal fold mass returns to normal.
During external procedures on the larynx there is often retraction or disruption of multiple tissue layers, including the muscles and vessels of the neck as well as reconstruction of these structures. Large vessels, such as the common carotid, internal or external carotid, the IJV, and their tributaries, may be encountered. If traumatized or resected, then large-volume blood loss may occur. The surgeon will need to be prepared to establish vascular control, which may require appropriate vascular instrumentation, surgical ties, titanium clips, or electrocautery. Blood loss is managed by consultation with the anesthetic staff and includes fluid replacement (colloid and/or crystalloid) and in some cases blood transfusion. In addition there is the possibility of air embolus when the IJV is transected. The surgeon and anesthetist should be alert to this possibility and use surgical vessel control and patient positioning to minimize this risk. Effective communication between the surgeon and anesthetist is vital. Large-vessel trauma requires appropriate exposure, control with pressure, vascular clips and ties, and consideration of reanastomosis in specific cases.
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Topical or subepithelial infusion
Epinephrine
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α1 receptor vasoconstrictor
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1:1000 to 1:10,000
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Thrombin-based products
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Floseal (Baxter, Deerfield, Illinois)
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TachoSil (Baxter, Deerfield, Illinois)
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