Townsend Courtney M.Jr., Evers B. Mark. Atlas of General Surgical Techniques: Expert Consult

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CHAPTER 1 • Thyroidectomy (Lobectomy, Subtotal Resection, Total Thyroidectomy) 15

FIGURE 1 –21

Right thyroid remnant

Left thyroid remnant

Inferior thyroid

artery

Parathyroid gland

Thyroid gland

16 Section I • Head and Neck and Endocrine Procedures

3. CLOSING

◆ Once resection is completed and hemostasis is ensured, closure is performed by ﬁ rst

reapproximating the strap muscles at the midline using interrupted 3-0 Vicryl sutures

(Figure 1-22).

◆ The platysma muscle is likewise reapproximated using interrupted 3-0 Vicryl sutures

(Figure 1-23).

◆ Finally, the skin is reapproximated with a subcuticular stitch of 4-0 Monocryl suture

(Figure 1-24).

STEP 4: POSTOPERATIVE CARE

◆ Although once routinely placed after thyroid resection, drains are seldom indicated.

◆ One of the most immediate postoperative complications can be wound hematoma, which

occurs in a small percentage of patients. It is more common in those patients who are

taking anticoagulant medications or nonsteroidal anti-inﬂ ammatory drugs (NSAIDs) or

who have had total thyroidectomy.

◆ A small hematoma in this location can severely compromise respirations and should be

immediately evacuated either in the operating room or, if this is not possible, at the

bedside.

◆ Injury of a recurrent laryngeal nerve can lead to hoarseness; bilateral injury of the recurrent

laryngeal nerves may result in paralysis of both vocal cords, which would require reintuba-

tion and possibly tracheostomy.

◆ Postoperative hypoparathyroidism is usually a transient phenomenon that is relatively rare

but occurs more often after total thyroidectomy. Calcium replacement and possibly vitamin

D may be required to maintain adequate serum calcium levels.

◆ In an uncomplicated thyroid lobectomy, patients may be discharged on the same day as

surgery.

CHAPTER 1 • Thyroidectomy (Lobectomy, Subtotal Resection, Total Thyroidectomy) 17

Sternohyoid muscle

Sternocleidomastoid

muscle

Thyroid cartilage

Anterior jugular vein

FIGURE 1 –22

Platysma muscle

FIGURE 1 –23

FIGURE 1 –24

18 Section I • Head and Neck and Endocrine Procedures

STEP 5: PEARLS AND PITFALLS

◆ The most dreaded complication of thyroid resection is damage to the recurrent laryngeal

nerve. It is imperative to identify the nerve throughout its course in the neck to avoid

injury.

◆ During thyroidectomy, the recurrent laryngeal nerve is at greatest risk of injury at the

ligament of Berry, during ligation of branches of the inferior thyroid artery, or at the

thoracic inlet.

◆ In most patients, the dissection can be carried out entirely through the cervical incision. In

the rare patient, a partial median sternotomy may be required for anterior mediastinal

lesions that cannot be safely mobilized through the cervical incision. This possibility should

be anticipated by preoperative physical examination.

SELECTED REFERENCES

1. Hanks JB: Thyroid. In Townsend CM Jr (ed): Sabiston Textbook of Surgery: The Biological Basis of

Modern Surgical Practice, 17th ed. Philadelphia, Saunders, 2004, pp 947-983.

2. Wong CKM, Wheeler MH: Thyroid nodules: Rational management. World J Surg 2000;24:934-941.

3. Schlumberger MJ: Papillary and follicular thyroid carcinoma. N Engl J Med 1998;338:297-306.

4. Clark OH: Surgical anatomy. In Braverman LE, Utiger RE (eds): Werner and Ingbar’s The Thyroid, 7th ed.

Philadelphia, Lippincott-Raven, 1996, pp 462-468.

STEP 1: SURGICAL ANATOMY

◆ Modiﬁ ed radical neck dissection (MRND) is a modiﬁ cation of the radical neck dissection de-

scribed by Crile in 1906. It includes the en bloc removal of all node-bearing tissues in the ante-

rior and posterior cervical triangles, the tail of the parotid gland, the submandibular gland, and

cervical sensory nerves with sparing of one of all of the following structures: the sternocleido-

mastoid (SCM) muscle, the internal jugular vein (IJV), and the spinal accessory nerve (SAN).

◆ A comprehensive understanding of all neck anatomy is critical and cannot be overestimated

(Figure 2-1). The SCM muscle was removed to show underlying structures (see Figure 2-1, B).

◆ Key structures include the platysma muscle, SCM muscle, anterior and posterior bellies of

the digastric muscle, posterior belly of the omohyoid muscle, trapezius muscle, marginal

mandibular branch of the facial nerve, brachial plexus, phrenic nerve, hypoglossal nerve,

SAN, thoracic duct, and contents of the carotid sheath.

◆ The SAN lies lateral to the IJV in 70% of patients, lies medial to the IJV in 27%, and passes

through the IJV in 3% of cases.

◆ The platysma is dehiscent in the lower anterior midline of the neck and posteriorly in the

area of the external jugular vein and the greater auricular nerve.

◆ The levels of the neck must be understood before the start of the operation. Lymph nodes

are contained in seven levels of the neck, which are deﬁ ned by certain anatomic boundaries:

◆ Level IA: The submental (triangle) is formed by the anterior bellies of the digastric mus-

cle and the hyoid bone.

◆ Level IB: The submandibular (triangle) is formed by the anterior and posterior bellies of

the digastric muscle and the body of the mandible superiorly.

◆ Level II: The upper jugular extends from the level of the skull base superiorly to the level

of the hyoid bone inferiorly and to the posterior border of the SCM muscle. It is divided

into Levels IIA and IIB by the SAN. Level IIA is located anterior to the SAN and Level IIB

is located posterior to the SAN.

CHAPTER

Modiﬁ ed Radical Neck

Dissection Preserving Spinal

Accessory Nerve

Anna M. Pou

◆ Level III: The mid-jugular extends from the hyoid bone superiorly to the level of the

cricoid cartilage inferiorly and to the posterior border of the SCM muscle.

◆ Level IV: The lower jugular extends from the level of the cricoid superiorly to the clavicle

inferiorly and to the posterior border of the SCM muscle.

◆ Level V: The posterior triangle (spinal accessory and transverse cervical) is bounded by

the anterior border of the trapezius muscle posteriorly, the posterior border of the SCM

muscle anteriorly, and the clavicle inferiorly. Sublevel VA (spinal accessory nodes) is

separated from VB (nodes following the transverse vessels) by a horizontal plane mark-

ing the inferior border of the anterior cricoid arch.

◆ Level VI: Contains the prelaryngeal (Delphian), pretracheal, and paratracheal (anterior

central compartment) nodes and extends from the hyoid bone superiorly to the supra-

sternal notch inferiorly and laterally to the medial border of the carotid sheath bilaterally.

◆ Level VII: The upper mediastinal is inferior to the suprasternal notch in the superior

mediastinum.

STEP 2: PREOPERATIVE CONSIDERATIONS

◆ Neck dissections are often done in conjunction with resection of the primary tumor. In this

case, the neck incision may be modiﬁ ed to include resection of both nodal disease and the

primary tumor. A tracheotomy may also be necessary.

◆ Indications for MRND with preservation of the SAN include the following:

◆ The presence of a clearly deﬁ ned plane between the SAN and tumor

◆ Bulky nodal disease (stage N2, N3)

◆ Persistent or recurrent nodal disease following radiation/chemoradiation therapy

◆ Preoperative counseling must include the possibility of sacriﬁ ce of cranial nerves if involved

with tumor, as well as the resulting deﬁ cits.

◆ Two units of packed red blood cells are typed, screened, and held for transfusion if

necessary.

◆ Perioperative antibiotics are given if the upper aerodigestive tract is to be entered to resect

the primary tumor.

◆ The patient’s airway should be discussed with the anesthesiologist before surgery. The

presence of a primary tumor, laryngeal edema, or effects of previous radiation therapy may

dictate ﬁ ber-optic intubation or awake, local tracheotomy.

◆ The proximity of nodal disease to the carotid sheath must be assessed for resectability.

Carotid artery balloon test occlusion is performed if there is suspicion of carotid artery

invasion. This will determine risk of cerebrovascular accident (CVA) if the carotid artery

is resected. Carotid artery resection with or without reconstruction using saphenous vein

graft is typically not considered except in radiation failures and recurrent disease.

◆ The surgeon must be able and prepared to modify the surgical plan and the order in which

various steps are performed if the tumor dictates such.

Section I • Head and Neck and Endocrine Procedures20

CHAPTER 2 • Modiﬁ ed Radical Neck Dissection Preserving Spinal Accessory Nerve 21

External jugular vein

Sternocleidomastoid muscle

SCM clavicle head

Superior thyroid

artery and vein

Anterior jugular vein

Facial artery and vein

Thyroid gland

SCM sternal head

Posterior auricular vein

Levator scapulae muscle

Scalene muscles

(anterior, middle, posterior)

Transverse cervical

artery and vein

Thoracic duct

Suprascapular artery

Subclavian artery

External jugular vein

Phrenic nerve, Brachial plexus

Lesser occipital nerve

C3 spinal nerve

Splenius muscle,

Trapezius muscle

C4 spinal nerve

Accessory nerve,

C2 spinal nerve

Facial artery and vein

Marginal mandibular

nerve

Superior thyroid artery and vein

Ansa cervicalis nerve

Internal jugular vein

Common carotid artery

Omohyoid muscle (posterior belly)

Omohyoid muscle

FIGURE 2 –1

22 Section I • Head and Neck and Endocrine Procedures

STEP 3: OPERATIVE STEPS

1. INCISION

◆ Following oral endotracheal intubation or tracheostomy, the patient is placed supine. The

neck is extended using a shoulder roll, and the head is stabilized using a doughnut

cushion. The ipsilateral arm is tucked and the bed is turned with the operative ﬁ eld facing

out (away from the anesthesiologist).

◆ Following induction of general anesthesia, muscle relaxants are not used. This allows

testing of cranial nerves with a nerve stimulator. This must be communicated to the

anesthesiologist.

◆ The surgical site is sterilely prepped with betadine from the level of the lower lip to right

above the nipples, including the lower face, earlobe, and posterior neck. The prep is ex-

tended across the midline of the neck. If the primary tumor is to be resected, this area is

also sterilely prepped in continuity with the neck and chest.

◆ The sterile drapes surrounding the head and neck ﬁ eld are stapled or sutured to the patient.

◆ There are many options for skin incisions, with the most commonly used ones seen here

(Figure 2-1, C [half H], Figure 2-1, D [modiﬁ ed Schobinger], Figure 2-1, E [hockey stick]).

The incision chosen depends on tumor location, including the primary tumor, and surgeon

preference. I prefer the hockey stick incision that slightly crosses midline (See Figure 2-1, E)

to avoid dropping a limb. If a limb is dropped, the trifurcation should be placed posterior to

the carotid artery. In the event of skin necrosis, the carotid artery would not be exposed with

this design.

◆ The incision is outlined on the neck using a sterile marking pen. The mastoid tip and

suprasternal notch are used as a reference.

◆ The skin and subcutaneous tissue are injected with 1% lidocaine with 1:100,000 epineph-

rine to obtain hemostasis.

◆ The superior and inferior skin ﬂ aps are raised in a subplatysmal plane to the level of the

mandibular body and the clavicle, respectively. The posterior aspect of the superior ﬂ ap

is raised in a plane lateral to the external jugular vein, great auricular nerve, and tail of

the parotid (Figure 2-2). Medially, the skin ﬂ ap is elevated slightly past the midline.

◆ If a tracheotomy is present, care must be taken not to violate the tracheotomy incision. If

this does occur, the tracheotomy incision must be separated from the remainder of the neck

incision to prevent contamination with air and mucus. This is done by sewing the subcuta-

neous tissue surrounding the tracheotomy site to the strap muscles.

CHAPTER 2 • Modiﬁ ed Radical Neck Dissection Preserving Spinal Accessory Nerve 23

C D E

FIGURE 2 –1, cont’d

External jugular vein

Greater auricular nerve

Lesser occipital nerve

FIGURE 2 –2

24 Section I • Head and Neck and Endocrine Procedures

◆ The superior and inferior skin ﬂ aps are secured to the drapes using 2-0 silk stick ties and

hemostats. During the dissection, retraction of the skin ﬂ aps should occasionally be

released to prevent venous congestion of the ﬂ aps.

◆ The posterior skin ﬂ ap can be elevated at this time or after the level I nodal dissection is

complete. I prefer the latter.

2. DISSECTION

◆ The superﬁ cial layer of the deep cervical fascia overlying the submandibular gland is

incised 1 cm anterior and 1 cm inferior to the angle of the mandible. The marginal

mandibular nerve will be found in this location. It lies lateral to the facial vessels. The

nerve is sharply dissected from the underlying tissue and elevated superiorly together with

the fascia (Figure 2-3). This is necessary in order to dissect the prevascular facial nodes.

◆ An Allis clamp is placed on the ﬁ bro-fatty tissue in the midline submental area lying between

the anterior bellies of the digastric muscle. This tissue is dissected in an inferior and posterior

direction, exposing both anterior muscle bellies and the central portion of the mylohyoid

muscle. The nerve and vessels to the mylohyoid are ligated. This tissue is left attached to the

hyoid bone (Figure 2-4).