- Email: [email protected]
Extended neck dissection
Operative Techniques in Otolaryngology (2004) 15, 184-189
Extended neck dissection Ashok R. Shaha, MD, FACS From the Memorial Sloan-Kettering Cancer Center, New York, New York. KEYWORDS Neck dissection; Carotid resection; Metastatic neck tumor; Head and neck cancer; Advanced head and neck tumor
The most important prognostic factor in the management of head and neck cancer is the presence of nodal metastasis. Nodal metastasis generally decreases survival by almost 50%. The classical surgical procedure for cervical metastasis has been radical neck dissection for almost 75 years. There has been a paradigm shift towards modified neck dissections and preserving vital structures, especially the accessory nerve. Occasionally, patients may present with advanced metastatic disease in the neck requiring extended neck dissection—removal of additional structures such as skin, platysma, hypoglossal nerve, posterior belly of the digastric muscle, vagus nerve, and occasionally carotid artery. There are select indications for extended neck dissection and with postoperative radiation therapy satisfactory local control can be achieved. Every surgeon involved in head and neck surgery should be familiar with the procedure of extended neck dissection, its operative technique and prognostic implications. © 2004 Elsevier Inc. All rights reserved.
The most important prognostic factor in patients with head and neck cancer is the presence of lymph node metastasis. Once the patient develops lymph node metastasis in the neck, the survival rate drops by approximately 50% and patients are grouped into stage III and IV (ie, advanced head and neck cancer).1-3 The classical management of patients with cervical node metastasis is neck dissection along with postoperative radiation therapy. There is a high incidence of nodal metastasis depending on the location of the primary tumor and the size of the primary. As the location of the tumor extends in the posterior oral cavity or oropharynx, the incidence of nodal metastasis is as high as 50% to 60%, whereas in patients with tumors of the hypopharynx, the incidence of nodal metastasis is approximately 75% to 80%. The classical surgical approach for these patients used to be standard radical neck dissection, which included removal of all lymph node basins in the neck (comprehensive) along with three important structures—sternomastoid muscle, internal jugular vein, and the accessory nerve. The classical radical neck dissection was described by George Crile Sr in his landmark article published in 1906 in JAMA.4 Several other leaders such as Oliver Bears and Hayes Martin also popularized radical neck dissection. Hayes Martin, in his landmark article in 1951, described in
Address reprint requests and correspondence: Ashok R. Shaha, MD, FACS, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021. E-mail address: [email protected].
1043-1810/$ -see front matter © 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2004.09.003
detail the technique of radical neck dissection.5 Radical neck dissection was a standard surgical procedure for almost three quarters of a century. Oswaldo Suarez6 of Argentina initially popularized functional neck dissection, wherein a select group of lymph nodes were removed, preserving the important structures in the neck. This operation became popular initially in Europe with the writings of Ettore Bocca of Italy. Modified neck dissection was popularized in the United States initially by Jesse, Ballentyne, and Byers from MD Anderson Cancer Institute in Houston, Texas.7,8 Since 1980, modified neck dissection has become very popular because of better understanding of the biology of metastatic disease in the neck and of the patterns of nodal metastasis from various primary sites in the head and neck region, as well as an increasing use of postoperative radiation therapy in patients with positive cervical nodes.9 There was increasing interest in the elective treatment of cervical nodes in patients with head and neck cancer. A variety of modified neck dissections were described initially. To standardize the nomenclature, the American Academy of Otolaryngology Head and Surgery reported neck dissections to be “comprehensive” when all lymph node basins in the neck are removed and “selective” when selected lymph node groups are removed.10,11 Comprehensive neck dissection was further classified into radical neck dissection, extended neck dissection, modified neck dissection; selective neck dissection was subdivided into supraomohyoid neck dissection, anterolateral neck dissection, posterolateral neck dissection, and central compartment node dissection. This article will discuss issues related to extended neck dissection,
Shaha
Extended Neck Dissection
185
Table 1 Staging of the regional lymph nodes (N stage) for SCC of the upper aerodigestive tract NX N0 N1 N2a
N2b N2c
N3
Regional lymph nodes cannot be assessed No regional lymph node metastasis Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension Metastasis in a lymph node more than 6 cm in greatest dimension
the structures commonly removed, and the procedure’s implications in overall prognosis. It will also discuss in detail the current role of carotid resection in patients with metastatic disease to the neck.
Indications and structures removed The American Joint Committee on Cancer Staging divided neck metastasis12 into N1, N2, and N3 (Table 1) N1 is described as lymph node metastasis 0 to 3 cm, N2 as 3 to 6 cm, and N3 as more than 6 cm. In the previous staging systems, N3 was described as a fixed nodal metastasis. However, the fixity of the neck nodes was dependent on the clinician’s physical findings; as a result, it was changed to the size more than 6 cm. Extended neck dissection implies removal of structures other than those commonly removed in radical neck dissection. It is generally used in patients who present with bulky nodal metastasis, soft tissue extension, or gross extranodal disease. It is also indicated in patients who present with involvement of the skin or platysma. Extension of the disease into the dermis is considered to be an ominous prognostic factor, especially if there is a major subdermal lymphatic invasion. Such patients will require wide excision of the skin, subcutaneous tissue, and platysma, along with appropriate reconstruction of the skin defect, generally with a pectoralis myocutaneous flap and postoperative radiation therapy. A select group of patients with advanced neck disease for whom operability is questionable may benefit from preoperative radiation therapy and planned neck dissection at the conclusion of 5,000 cGy or more. Occasionally, in patients with inoperable disease, one may consider chemoradiation therapy to the full course; then, if there is a residual palpable disease, an extended neck dissection may be considered. However, the overall salvage rate in this group of patients is generally quite small. The structures commonly removed in extended neck dissection include skin, platysma, posterior belly of the digastric, the styloid group of muscles, hypoglossal nerve, external carotid artery, and periosteum of the mandible; rarely, the vagus, phrenic, or sympathetic trunk may need to be removed. If the tumor is adherent to the deeper structures
Figure 1 Patient with bulky nodal metastasis in the posterior neck, requiring sacrifice of portion of the splenius capitis, accessory nerve, posterior belly of the digastric, and stylohyoid muscles. (Color version of figure is available online.)
of the neck, the levator scapulae muscle or splenius capitis muscle may need to be removed (Figures 1 and 2). However, overall local control with extension of the disease in the prevertebral and paravertebral muscles is very limited. Resection of the internal or common carotid artery is rarely undertaken and will be described as a separate entity.
Surgical technique In a primary-tumor situation when the patient has not been treated previously, a thorough clinical evaluation of the extent of the disease and the structures involved is essential. A complete examination of the head and neck, including fiberoptic laryngoscopy, is necessary to evaluate vocal cord function and status of the vagus nerve. The fixity of the disease to deeper structures needs to be evaluated, and clinical evaluation of surrounding structures’ involvement is very important. Appropriate imaging studies include a computed tomography scan or magnetic resonance imaging. Rarely, carotid angiogram may be necessary to evaluate the extent of the disease. However, generally magnetic reso-
Figure 2 Patient with very advanced metastatic tumor in the neck with tumor fungating through the skin, requiring extended radical neck dissection, wide excision of the skin and platysma, and reconstruction with pectoralis myocutaneous flap. (Color version of figure is available online.)
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nance imaging and magnetic resonance angiography are quite sufficient to evaluate the extent of the disease. The proximity of the tumor to the base of the skull and mandible are also important considerations. If there is disease at level IV, it is very important to evaluate the mediastinum to see if there is any direct extension of the disease in the tracheoesophageal groove or along the trachea. The primary surgical procedure will include extended neck dissection with sacrifice of the involved structures along with removal of the primary tumor, whether in the oral cavity by composite resection or in the laryngopharyngeal area by appropriate laryngopharyngectomy. Before surgical intervention, it is vitally important to plan appropriate reconstruction, whether pectoralis myocutaneous flap, latissimus flap, or a free flap such as radial forearm or rectus abdominus flap. It is also important to evaluate the general condition of the patient, comorbid states, and comorbidity evaluation. Sacrifice of the vagus and hypoglossal nerve may lead to considerable problems related to aspiration and swallowing. In elderly patients with a fragile general condition, aspiration may be quite detrimental and the patient may need long-term tube feedings or percutaneous endoscopic gastrostomy. The need for extended neck dissection can generally be determined preoperatively based on the clinical evaluation, appropriate imaging studies, and the proximity of the metastatic disease to the vital structures. The head and neck surgeon may need to make a decision regarding operability and inoperability of the disease in the neck. Occasionally, the case may need to be discussed by the Tumor Board. There is also a high incidence of pulmonary metastasis in patients who present with advanced neck disease and, before any major surgical undertaking, it would be important to rule out pulmonary metastasis either with a routine chest radiograph or with a computed tomography scan of the chest. Positron emission tomography is also very helpful to evaluate distant metastasis.
Operative technique If the skin is not involved by the tumor, the operation essentially begins as a standard radical neck dissection with a modified Schobinger incision. If the tumor involves the skin, appropriate wide excision of the skin should be performed with planned soft tissue reconstruction. Posterior dissection of the neck includes sacrifice of the accessory nerve, dissection up to the trapezius muscle, and removal of the sternomastoid muscle from its origin near the mastoid process. As the dissection continues, the deeper extent of the disease can be evaluated, and the operating surgeon should make a decision based on the clinical findings and preoperative imaging studies about the nature of extended neck dissection. The posterior belly of the digastric and the stylohyoid muscles are commonly removed. At this time, a decision needs to be made regarding the sacrifice of the hypoglossal nerve and mylohyoid muscle. The jugular vein is routinely transected near the clavicle and high near the skull base. The occipital artery is ligated. If the disease extends and is adherent to the mandible, the periosteum can be peeled off along with the main bulk of the disease.
Occasionally, a reverse marginal mandibulectomy may be necessary for en bloc removal of the neck disease adherent to the mandible. If there is extensive disease in the tail of the parotid, the incision needs to be extended in modified Blair fashion to the pretragal area and superficial parotidectomy performed with identification and preservation of the facial nerve and its branches. Occasionally, one may need dissection of the facial group of lymph nodes, in which case there is a high probability of injury to the ramus mandibularis and resultant lip weakness. As the dissection is continued medially, a decision needs to be made regarding sacrifice of the external carotid artery. Most of the time, the common carotid and internal carotid artery can be easily preserved in primary surgical procedures because the disease can be peeled off the adventitia or may necessitate, rarely, subadventitial dissection. However, this may be more difficult in patients who have received previous radiation therapy. Medially, it is important to evaluate strap muscles, superior belly of the omohyoid, and parapharyngeal musculature. Occasionally, if the disease extends medially, a portion of the constrictor muscles may need to be removed, which may result in difficulty in swallowing. After ligating the lower portion of the jugular vein, the dissection is continued superiorly between the jugular vein and the common carotid artery. If the tumor is invading the carotid sheath, the surgeon has to make a decision regarding sacrifice of the vagus and sympathetic trunk. The scaleni muscles and phrenic nerve rarely need to be resected, and the brachial plexus branches are rarely resected. After resection of the primary tumor, a decision needs to be made as to whether there is any role for intraoperative radiation therapy or brachytherapy. Obviously, this needs to be planned well in advance so that appropriate assistance is rendered from radiation therapists for either intraoperative radiation therapy or planned brachytherapy with iodine seeds or insertion of after-loading catheters. This is more crucial in patients who have previously received radiation therapy, and a salvage neck dissection is performed. In patients undergoing salvage neck surgery, it is vitally important to discuss with the radiation therapist the feasibility of additional radiation dosage. If brachytherapy is to be undertaken, especially with after-loading catheters, the carotid artery needs to be protected with soft tissue coverage such as pectoralis myocutaneous flap. The muscle flap will also help protect the carotid artery and the carotid bulb. The dermis grafts that were used in the 1970s and 1980s are rarely used today in lieu of either myocutaneous flap or free flap reconstruction of the neck. Meticulous dissection is undertaken in the supraclavicular fossa, especially behind the jugular vein, to avoid injury to the lymphatics and thoracic duct. The lymphatic injury may lead to postoperative chyle leak, which can be a very difficult situation to treat and may lead to considerable induration and edema of the skin with persistent chyle leak and an extended hospitalization.
Outcome and prognostic factors Shaha described his experience at the SUNY Health Science Center in Brooklyn, NY, of extended neck dissections per-
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Figure 3 Extensive tumor involving the upper neck and the parotid area, requiring sacrifice of the lower division of the facial nerve and resection of the parotid gland. (Color version of figure is available online.)
formed on 40 patients.13 All the patients had N2 and N3 disease. Nine were unknown primaries. Thirteen patients had their primary in the oral cavity, and eleven had it in the laryngopharyngeal area. Five patients had primary tumor in the salivary glands, and two patients had metastatic melanoma. Patients undergoing extensive skin excision were reconstructed with pectoralis myocutaneous flap. All patients received postoperative radiation therapy. Local control was reported in 70% of patients. The author reported the most difficult region for local control was the disease behind the mastoid process, and the most difficult problems were patients with subdermal lymphatics. However, the author reported definite indications of extended neck dissection with satisfactory local control in the neck. The author also noted the most difficult area for local control was extension of the disease in the levator scapulae and scaleni muscles. Shaha also noted that the morbidity of extended neck dissection was not excessive compared with standard radical neck dissection. Residual disability after sacrificing structures such as hypoglossal nerve, the vagus, and the sympathetic trunk was minimal. The author concluded that although there is a definite trend toward minimizing disability from radical neck dissection by operative modifications, in certain select circumstances there is a definite role for extended neck dissection, which can be used for the control of malignant disease in the neck with minimally added complications, morbidity, or mortality (Figures 3-5). Recently, Carew and Spiro14 of the Memorial Sloan-Kettering Cancer Center reported their experience with 106 patients (5% of all neck dissections) who had undergone extended neck dissection. Most (76 patients) had metastatic squamous cell carcinoma that had extended to extranodal structures and to external structures in the upper neck. The authors reported 5-year disease-free survival to be 39%, and the disease was controlled in the neck in 72 patients (68%), with a median follow-up of 5.5 years. The authors noted a trend toward better survival in patients with squamous cell carcinoma (47% at 5 years) compared with those with other histologies (24% at 5 years). Patients with levels I, II, and III involved nodal metastasis had better survival (46% at 5 years) than those with level IV and V or multiple levels involved (14% at 5 years). In patients who had received previous radiation therapy and underwent extended neck dissection, the survival was only 22% at 5 years compared with 47% for those
Figure 4 Patient with metastatic tumor at level IV. The tumor required extensive dissection in the tracheoesophageal area with postoperative radiation therapy extending to the mediastinum. (Color version of figure is available online.)
who received postoperative radiation therapy. The authors concluded that although advanced neck disease invading adjacent structures remains an ominous sign, neck control and 5-year survival were achieved in nearly half the patients with multi-modality therapy.
Retropharyngeal nodal metastasis The incidence and management of retropharyngeal nodal metastasis remains to some extent unclear in the head and neck literature. However, retropharyngeal, parapharyngeal, paratracheal, and mediastinal nodes may occasionally be involved, especially when primary tumors are originating in
Figure 5 Patient with metastatic tumor adherent to the constrictor muscles, requiring sacrifice of portion of the constrictor muscles, vagus nerve, sympathetic trunk, and phrenic nerve. (Color version of figure is available online.)
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Operative Techniques in Otolaryngology, Vol 15, No 3, September 2004 In patients with hypopharyngeal tumor with retropharyngeal lymph node metastasis, consideration may be given to circumferential pharyngectomy and appropriate reconstruction for clearance of the prevertebral tissue.
Carotid artery and neck dissection The following issues are related to management of carotid artery in neck dissection:16 1. Management of carotid artery in primary surgery 2. Elective resection of the carotid artery 3. Inadvertent ligation of the carotid artery during neck dissection 4. Carotid blow out Figure 6 Computed tomography scan of the patient with bulky metastatic disease; however, the carotid artery is displaced on one side. A neck dissection could be performed by subadventitial dissection on the surface of the carotid artery.
the nasopharynx, hypopharynx, or oropharynx.15 These nodal groups are not removed by conventional neck dissection and, in certain circumstances, they may be at high risk for developing metastasis. The retropharyngeal nodes are noted in the retropharyngeal space, which is situated posterior to the pharyngeal structures and is bound anteriorly by the pharyngeal constrictor muscles and posteriorly by the prevertebral fascia and carotid sheath on either side. Superiorly, the space extends up to the skull base, whereas inferiorly it continues into the retroesophageal space and superior mediastinum. The retropharyngeal nodes are commonly divided into lateral and medial group of nodes. Retropharyngeal nodes are the first echelon from nasopharynx, whereas the posterior pharyngeal wall has first echelon drainage to both retropharyngeal and jugulodigastric nodes. The clinical evaluation of these nodes may be quite difficult, and appropriate imaging studies such as computed tomography scan or magnetic resonance imaging may be helpful. The incidence of metastatic disease to these lymph nodes varies between 5% and 80%, depending on the site of the primary tumor. The highest incidence is noted in tumors of the nasopharynx, posterior pharyngeal wall, and cervical esophagus. Treatment of the retropharyngeal node metastasis depends on the site of the primary tumor and the treatment approaches undertaken. Radiation therapy with chemotherapy is the standard treatment for both primary tumor and nodal metastasis from nasopharyngeal tumors. Surgical dissection of the retropharyngeal nodes during initial surgery should be performed in advanced tumors of the oropharynx and hypopharynx. Although retropharyngeal node dissection is technically difficult, it should be considered during the standard neck dissection by retracting the carotid artery laterally and dissecting medial to the carotid artery in the retropharyngeal area. Intensity modulated radiation therapy appears to be much more effective at rendering the appropriate dosage to this area without damaging the spinal cord. Conventional radiation therapy may underdose the retropharyngeal nodes to avoid spinal cord complications.
During primary surgery, the carotid artery is rarely an issue. Even in large tumors, most of the time the disease can be easily peeled off the carotid artery, especially with subadventitial dissection. If the soft tissues around the skin are normal, the carotid artery does not require any specific protection. It may be necessary to protect the carotid artery if there is going to be a pharyngeal suture line or pharyngeal resection. Pharyngeal fistula and salivary leak can be very detrimental to the carotid artery. The carotid adventitia may become weak and blow out. Most of the time, the issue of carotid artery resection comes in patients who are undergoing salvage surgery or who have extensive metastatic disease in the neck encircling more than 180° of the carotid. Initial clinical evaluation and imaging studies will indicate that carotid resection may be necessary for satisfactory and complete resection of the metastatic tumor in the neck. There is a very high incidence of neuromorbidity and post-
Figure 7 Patient with extensive metastatic disease; however, the tumor does not encircle the carotid artery and extends only on a 180° angle sideways. The neck dissection could be performed with sacrifice of the vagus nerve and the sympathetic trunk.
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Extended Neck Dissection
operative mortality in patients undergoing carotid resection. The most common complication is related to neurological events such as stroke, hemiplegia, and loss of speech. Rarely, it may lead to blindness. The issue of carotid resection needs to be evaluated in the proper perspective with sound oncologic principles. If the tumor appears to be adherent to the carotid artery and resecting the carotid artery will mean a potential cure, one may consider resection and reconstruction of the carotid artery; however, this is a rare situation (Figures 6 and 7). The majority of the time when the tumor is adherent to the carotid artery, it invades the surrounding structures such as the carotid sheath, vagus nerve, phrenic, sympathetic trunk, and scaleni muscles. Unless the surgeon strongly feels that all gross tumor cannot be removed along with carotid resection, it should not be undertaken because of the very high incidence of local recurrence, overall poor prognosis, and potential complications, as well as a high incidence of neuromorbidity and mortality. Palliative carotid resection should not be considered. If there is any consideration of resecting the carotid artery, it is important to have a vascular surgeon available for reconstructing the carotid artery. The most common technique employed is the use of Gortex graft as an interposition graft. However, Gortex graft is not most suitable in patients undergoing pharyngeal resection or if there is a potential of pharyngocutaneous fistula. Under these circumstances, the saphenous vein is the best alternative.
Carotid blow Carotid rupture and carotid blow out was a common complication of head and neck surgical procedures in the 1970s and 1980s. Fortunately, this complication is currently a rare event as a result of better surgical techniques, improved radiation techniques, and the use of carotid protection with pectoralis myocutaneous flap or free flaps. Both the pectoralis myocutaneous flap and free flap protect the carotid artery with extensive soft tissue coverage. Carotid rupture is commonly noted in patients who have undergone previous radiation therapy and who have a pharyngeal leak with carotid artery bathing in the saliva. The radiation therapy leads to weakening of the carotid sheath. The carotid blow out used to be a catastrophic complication with a dire emergency. Most of the time, the bleeding can be controlled with pressure; however, the patient needs to be brought to
189 the operating room and the carotid artery ligated. This procedure has a very high complication rate related to neurological complications such as stroke and hemiplegia; there is also a high incidence of postoperative mortality. Rarely, multiply recurrent tumor may invade the carotid artery directly with necrosis of the medial border of the carotid artery, leading to extensive bleeding in the oropharyngeal area and subsequent exsanguination. However, this complication is seen very rarely today.
References 1. Shah JP: Patterns of cervical lymph node metastasis from squamous cell carcinomas of the upper aerodigestive tract. Am J Surg 160:405409, 1990 2. Shah JP, Medina J, Shaha AR, et al: Cervical lymph node metastasis. Curr Prob Surg 30:1-335, 1993 3. Kowalski LP, Medina JP: Nodal metastases: Predictive factors. Otolaryngol Clin North Am 31:621-637, 1998 4. Crile GW: Excision of cancer of the head and neck with special reference to the plan of dissection based on one hundred and thirty-two operations. JAMA 47:1780-1786, 1906 5. Martin H, DelValle B, Ehrlich H, et al: Neck dissection. Cancer 4:441-499, 1951 6. Suarez O: El problema se las metastasis linfticas y alejadas del cancer de laringe e hypopharinge. Rev Otorhinolaryngol 23:83-89, 1963 7. Byers RM, Wolf PF, Ballantyne AJ: Rationale for elective modified neck dissection. Head Neck 10:160-167, 1988 8. Byers RM: Modified neck dissection. A study of 967 cases from 1970 to 1980. Am J Surg 150:414-421, 1985 9. Shah JP: Cervical lymph node metastases: Diagnostic, therapeutic and prognostic implications. Oncology (Huntingt) 4:61-69, 1990 10. Medina JE: A rational classification of neck dissections. Otolaryngol Head Neck Surg 100:169-176, 1989 11. Robbins KT, Clayman G, Levine PA, et al: Neck dissection classification update: Revisions proposed by the American Head and Neck Society and the American Academy of Otolaryngology-Head and Neck Surgery. Arch Otolaryngol Head Neck Surg 2002;128:751-758 12. American Joint Committee on Cancer: AJCC Cancer Staging Handbook, 6th ed. New York, NY, Springer Verlag, 2002 13. Shaha AR: Extended neck dissection. J Surg Oncol 45:229-233, 1990 14. Carew JF, Spiro RH: Extended neck dissection. Am J Surg 174:485489, 1997 15. Ferlito A, Shaha AR, Rinaldo A: Retropharyngeal lymph node metastasis from cancer of the head and neck Acta Otolaryngol (Stockholm) 122:556-560, 2002 16. Gavilan J, Ferlito A, Silver CE, et al: The status of carotid resection in head and neck cancer. Acta Otolaryngol (Stockholm) 122:453-455, 2002
Extended neck dissection Ashok R. Shaha, MD, FACS From the Memorial Sloan-Kettering Cancer Center, New York, New York. KEYWORDS Neck dissection; Carotid resection; Metastatic neck tumor; Head and neck cancer; Advanced head and neck tumor
The most important prognostic factor in the management of head and neck cancer is the presence of nodal metastasis. Nodal metastasis generally decreases survival by almost 50%. The classical surgical procedure for cervical metastasis has been radical neck dissection for almost 75 years. There has been a paradigm shift towards modified neck dissections and preserving vital structures, especially the accessory nerve. Occasionally, patients may present with advanced metastatic disease in the neck requiring extended neck dissection—removal of additional structures such as skin, platysma, hypoglossal nerve, posterior belly of the digastric muscle, vagus nerve, and occasionally carotid artery. There are select indications for extended neck dissection and with postoperative radiation therapy satisfactory local control can be achieved. Every surgeon involved in head and neck surgery should be familiar with the procedure of extended neck dissection, its operative technique and prognostic implications. © 2004 Elsevier Inc. All rights reserved.
The most important prognostic factor in patients with head and neck cancer is the presence of lymph node metastasis. Once the patient develops lymph node metastasis in the neck, the survival rate drops by approximately 50% and patients are grouped into stage III and IV (ie, advanced head and neck cancer).1-3 The classical management of patients with cervical node metastasis is neck dissection along with postoperative radiation therapy. There is a high incidence of nodal metastasis depending on the location of the primary tumor and the size of the primary. As the location of the tumor extends in the posterior oral cavity or oropharynx, the incidence of nodal metastasis is as high as 50% to 60%, whereas in patients with tumors of the hypopharynx, the incidence of nodal metastasis is approximately 75% to 80%. The classical surgical approach for these patients used to be standard radical neck dissection, which included removal of all lymph node basins in the neck (comprehensive) along with three important structures—sternomastoid muscle, internal jugular vein, and the accessory nerve. The classical radical neck dissection was described by George Crile Sr in his landmark article published in 1906 in JAMA.4 Several other leaders such as Oliver Bears and Hayes Martin also popularized radical neck dissection. Hayes Martin, in his landmark article in 1951, described in
Address reprint requests and correspondence: Ashok R. Shaha, MD, FACS, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021. E-mail address: [email protected].
1043-1810/$ -see front matter © 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2004.09.003
detail the technique of radical neck dissection.5 Radical neck dissection was a standard surgical procedure for almost three quarters of a century. Oswaldo Suarez6 of Argentina initially popularized functional neck dissection, wherein a select group of lymph nodes were removed, preserving the important structures in the neck. This operation became popular initially in Europe with the writings of Ettore Bocca of Italy. Modified neck dissection was popularized in the United States initially by Jesse, Ballentyne, and Byers from MD Anderson Cancer Institute in Houston, Texas.7,8 Since 1980, modified neck dissection has become very popular because of better understanding of the biology of metastatic disease in the neck and of the patterns of nodal metastasis from various primary sites in the head and neck region, as well as an increasing use of postoperative radiation therapy in patients with positive cervical nodes.9 There was increasing interest in the elective treatment of cervical nodes in patients with head and neck cancer. A variety of modified neck dissections were described initially. To standardize the nomenclature, the American Academy of Otolaryngology Head and Surgery reported neck dissections to be “comprehensive” when all lymph node basins in the neck are removed and “selective” when selected lymph node groups are removed.10,11 Comprehensive neck dissection was further classified into radical neck dissection, extended neck dissection, modified neck dissection; selective neck dissection was subdivided into supraomohyoid neck dissection, anterolateral neck dissection, posterolateral neck dissection, and central compartment node dissection. This article will discuss issues related to extended neck dissection,
Shaha
Extended Neck Dissection
185
Table 1 Staging of the regional lymph nodes (N stage) for SCC of the upper aerodigestive tract NX N0 N1 N2a
N2b N2c
N3
Regional lymph nodes cannot be assessed No regional lymph node metastasis Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension Metastasis in a lymph node more than 6 cm in greatest dimension
the structures commonly removed, and the procedure’s implications in overall prognosis. It will also discuss in detail the current role of carotid resection in patients with metastatic disease to the neck.
Indications and structures removed The American Joint Committee on Cancer Staging divided neck metastasis12 into N1, N2, and N3 (Table 1) N1 is described as lymph node metastasis 0 to 3 cm, N2 as 3 to 6 cm, and N3 as more than 6 cm. In the previous staging systems, N3 was described as a fixed nodal metastasis. However, the fixity of the neck nodes was dependent on the clinician’s physical findings; as a result, it was changed to the size more than 6 cm. Extended neck dissection implies removal of structures other than those commonly removed in radical neck dissection. It is generally used in patients who present with bulky nodal metastasis, soft tissue extension, or gross extranodal disease. It is also indicated in patients who present with involvement of the skin or platysma. Extension of the disease into the dermis is considered to be an ominous prognostic factor, especially if there is a major subdermal lymphatic invasion. Such patients will require wide excision of the skin, subcutaneous tissue, and platysma, along with appropriate reconstruction of the skin defect, generally with a pectoralis myocutaneous flap and postoperative radiation therapy. A select group of patients with advanced neck disease for whom operability is questionable may benefit from preoperative radiation therapy and planned neck dissection at the conclusion of 5,000 cGy or more. Occasionally, in patients with inoperable disease, one may consider chemoradiation therapy to the full course; then, if there is a residual palpable disease, an extended neck dissection may be considered. However, the overall salvage rate in this group of patients is generally quite small. The structures commonly removed in extended neck dissection include skin, platysma, posterior belly of the digastric, the styloid group of muscles, hypoglossal nerve, external carotid artery, and periosteum of the mandible; rarely, the vagus, phrenic, or sympathetic trunk may need to be removed. If the tumor is adherent to the deeper structures
Figure 1 Patient with bulky nodal metastasis in the posterior neck, requiring sacrifice of portion of the splenius capitis, accessory nerve, posterior belly of the digastric, and stylohyoid muscles. (Color version of figure is available online.)
of the neck, the levator scapulae muscle or splenius capitis muscle may need to be removed (Figures 1 and 2). However, overall local control with extension of the disease in the prevertebral and paravertebral muscles is very limited. Resection of the internal or common carotid artery is rarely undertaken and will be described as a separate entity.
Surgical technique In a primary-tumor situation when the patient has not been treated previously, a thorough clinical evaluation of the extent of the disease and the structures involved is essential. A complete examination of the head and neck, including fiberoptic laryngoscopy, is necessary to evaluate vocal cord function and status of the vagus nerve. The fixity of the disease to deeper structures needs to be evaluated, and clinical evaluation of surrounding structures’ involvement is very important. Appropriate imaging studies include a computed tomography scan or magnetic resonance imaging. Rarely, carotid angiogram may be necessary to evaluate the extent of the disease. However, generally magnetic reso-
Figure 2 Patient with very advanced metastatic tumor in the neck with tumor fungating through the skin, requiring extended radical neck dissection, wide excision of the skin and platysma, and reconstruction with pectoralis myocutaneous flap. (Color version of figure is available online.)
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nance imaging and magnetic resonance angiography are quite sufficient to evaluate the extent of the disease. The proximity of the tumor to the base of the skull and mandible are also important considerations. If there is disease at level IV, it is very important to evaluate the mediastinum to see if there is any direct extension of the disease in the tracheoesophageal groove or along the trachea. The primary surgical procedure will include extended neck dissection with sacrifice of the involved structures along with removal of the primary tumor, whether in the oral cavity by composite resection or in the laryngopharyngeal area by appropriate laryngopharyngectomy. Before surgical intervention, it is vitally important to plan appropriate reconstruction, whether pectoralis myocutaneous flap, latissimus flap, or a free flap such as radial forearm or rectus abdominus flap. It is also important to evaluate the general condition of the patient, comorbid states, and comorbidity evaluation. Sacrifice of the vagus and hypoglossal nerve may lead to considerable problems related to aspiration and swallowing. In elderly patients with a fragile general condition, aspiration may be quite detrimental and the patient may need long-term tube feedings or percutaneous endoscopic gastrostomy. The need for extended neck dissection can generally be determined preoperatively based on the clinical evaluation, appropriate imaging studies, and the proximity of the metastatic disease to the vital structures. The head and neck surgeon may need to make a decision regarding operability and inoperability of the disease in the neck. Occasionally, the case may need to be discussed by the Tumor Board. There is also a high incidence of pulmonary metastasis in patients who present with advanced neck disease and, before any major surgical undertaking, it would be important to rule out pulmonary metastasis either with a routine chest radiograph or with a computed tomography scan of the chest. Positron emission tomography is also very helpful to evaluate distant metastasis.
Operative technique If the skin is not involved by the tumor, the operation essentially begins as a standard radical neck dissection with a modified Schobinger incision. If the tumor involves the skin, appropriate wide excision of the skin should be performed with planned soft tissue reconstruction. Posterior dissection of the neck includes sacrifice of the accessory nerve, dissection up to the trapezius muscle, and removal of the sternomastoid muscle from its origin near the mastoid process. As the dissection continues, the deeper extent of the disease can be evaluated, and the operating surgeon should make a decision based on the clinical findings and preoperative imaging studies about the nature of extended neck dissection. The posterior belly of the digastric and the stylohyoid muscles are commonly removed. At this time, a decision needs to be made regarding the sacrifice of the hypoglossal nerve and mylohyoid muscle. The jugular vein is routinely transected near the clavicle and high near the skull base. The occipital artery is ligated. If the disease extends and is adherent to the mandible, the periosteum can be peeled off along with the main bulk of the disease.
Occasionally, a reverse marginal mandibulectomy may be necessary for en bloc removal of the neck disease adherent to the mandible. If there is extensive disease in the tail of the parotid, the incision needs to be extended in modified Blair fashion to the pretragal area and superficial parotidectomy performed with identification and preservation of the facial nerve and its branches. Occasionally, one may need dissection of the facial group of lymph nodes, in which case there is a high probability of injury to the ramus mandibularis and resultant lip weakness. As the dissection is continued medially, a decision needs to be made regarding sacrifice of the external carotid artery. Most of the time, the common carotid and internal carotid artery can be easily preserved in primary surgical procedures because the disease can be peeled off the adventitia or may necessitate, rarely, subadventitial dissection. However, this may be more difficult in patients who have received previous radiation therapy. Medially, it is important to evaluate strap muscles, superior belly of the omohyoid, and parapharyngeal musculature. Occasionally, if the disease extends medially, a portion of the constrictor muscles may need to be removed, which may result in difficulty in swallowing. After ligating the lower portion of the jugular vein, the dissection is continued superiorly between the jugular vein and the common carotid artery. If the tumor is invading the carotid sheath, the surgeon has to make a decision regarding sacrifice of the vagus and sympathetic trunk. The scaleni muscles and phrenic nerve rarely need to be resected, and the brachial plexus branches are rarely resected. After resection of the primary tumor, a decision needs to be made as to whether there is any role for intraoperative radiation therapy or brachytherapy. Obviously, this needs to be planned well in advance so that appropriate assistance is rendered from radiation therapists for either intraoperative radiation therapy or planned brachytherapy with iodine seeds or insertion of after-loading catheters. This is more crucial in patients who have previously received radiation therapy, and a salvage neck dissection is performed. In patients undergoing salvage neck surgery, it is vitally important to discuss with the radiation therapist the feasibility of additional radiation dosage. If brachytherapy is to be undertaken, especially with after-loading catheters, the carotid artery needs to be protected with soft tissue coverage such as pectoralis myocutaneous flap. The muscle flap will also help protect the carotid artery and the carotid bulb. The dermis grafts that were used in the 1970s and 1980s are rarely used today in lieu of either myocutaneous flap or free flap reconstruction of the neck. Meticulous dissection is undertaken in the supraclavicular fossa, especially behind the jugular vein, to avoid injury to the lymphatics and thoracic duct. The lymphatic injury may lead to postoperative chyle leak, which can be a very difficult situation to treat and may lead to considerable induration and edema of the skin with persistent chyle leak and an extended hospitalization.
Outcome and prognostic factors Shaha described his experience at the SUNY Health Science Center in Brooklyn, NY, of extended neck dissections per-
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Figure 3 Extensive tumor involving the upper neck and the parotid area, requiring sacrifice of the lower division of the facial nerve and resection of the parotid gland. (Color version of figure is available online.)
formed on 40 patients.13 All the patients had N2 and N3 disease. Nine were unknown primaries. Thirteen patients had their primary in the oral cavity, and eleven had it in the laryngopharyngeal area. Five patients had primary tumor in the salivary glands, and two patients had metastatic melanoma. Patients undergoing extensive skin excision were reconstructed with pectoralis myocutaneous flap. All patients received postoperative radiation therapy. Local control was reported in 70% of patients. The author reported the most difficult region for local control was the disease behind the mastoid process, and the most difficult problems were patients with subdermal lymphatics. However, the author reported definite indications of extended neck dissection with satisfactory local control in the neck. The author also noted the most difficult area for local control was extension of the disease in the levator scapulae and scaleni muscles. Shaha also noted that the morbidity of extended neck dissection was not excessive compared with standard radical neck dissection. Residual disability after sacrificing structures such as hypoglossal nerve, the vagus, and the sympathetic trunk was minimal. The author concluded that although there is a definite trend toward minimizing disability from radical neck dissection by operative modifications, in certain select circumstances there is a definite role for extended neck dissection, which can be used for the control of malignant disease in the neck with minimally added complications, morbidity, or mortality (Figures 3-5). Recently, Carew and Spiro14 of the Memorial Sloan-Kettering Cancer Center reported their experience with 106 patients (5% of all neck dissections) who had undergone extended neck dissection. Most (76 patients) had metastatic squamous cell carcinoma that had extended to extranodal structures and to external structures in the upper neck. The authors reported 5-year disease-free survival to be 39%, and the disease was controlled in the neck in 72 patients (68%), with a median follow-up of 5.5 years. The authors noted a trend toward better survival in patients with squamous cell carcinoma (47% at 5 years) compared with those with other histologies (24% at 5 years). Patients with levels I, II, and III involved nodal metastasis had better survival (46% at 5 years) than those with level IV and V or multiple levels involved (14% at 5 years). In patients who had received previous radiation therapy and underwent extended neck dissection, the survival was only 22% at 5 years compared with 47% for those
Figure 4 Patient with metastatic tumor at level IV. The tumor required extensive dissection in the tracheoesophageal area with postoperative radiation therapy extending to the mediastinum. (Color version of figure is available online.)
who received postoperative radiation therapy. The authors concluded that although advanced neck disease invading adjacent structures remains an ominous sign, neck control and 5-year survival were achieved in nearly half the patients with multi-modality therapy.
Retropharyngeal nodal metastasis The incidence and management of retropharyngeal nodal metastasis remains to some extent unclear in the head and neck literature. However, retropharyngeal, parapharyngeal, paratracheal, and mediastinal nodes may occasionally be involved, especially when primary tumors are originating in
Figure 5 Patient with metastatic tumor adherent to the constrictor muscles, requiring sacrifice of portion of the constrictor muscles, vagus nerve, sympathetic trunk, and phrenic nerve. (Color version of figure is available online.)
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Operative Techniques in Otolaryngology, Vol 15, No 3, September 2004 In patients with hypopharyngeal tumor with retropharyngeal lymph node metastasis, consideration may be given to circumferential pharyngectomy and appropriate reconstruction for clearance of the prevertebral tissue.
Carotid artery and neck dissection The following issues are related to management of carotid artery in neck dissection:16 1. Management of carotid artery in primary surgery 2. Elective resection of the carotid artery 3. Inadvertent ligation of the carotid artery during neck dissection 4. Carotid blow out Figure 6 Computed tomography scan of the patient with bulky metastatic disease; however, the carotid artery is displaced on one side. A neck dissection could be performed by subadventitial dissection on the surface of the carotid artery.
the nasopharynx, hypopharynx, or oropharynx.15 These nodal groups are not removed by conventional neck dissection and, in certain circumstances, they may be at high risk for developing metastasis. The retropharyngeal nodes are noted in the retropharyngeal space, which is situated posterior to the pharyngeal structures and is bound anteriorly by the pharyngeal constrictor muscles and posteriorly by the prevertebral fascia and carotid sheath on either side. Superiorly, the space extends up to the skull base, whereas inferiorly it continues into the retroesophageal space and superior mediastinum. The retropharyngeal nodes are commonly divided into lateral and medial group of nodes. Retropharyngeal nodes are the first echelon from nasopharynx, whereas the posterior pharyngeal wall has first echelon drainage to both retropharyngeal and jugulodigastric nodes. The clinical evaluation of these nodes may be quite difficult, and appropriate imaging studies such as computed tomography scan or magnetic resonance imaging may be helpful. The incidence of metastatic disease to these lymph nodes varies between 5% and 80%, depending on the site of the primary tumor. The highest incidence is noted in tumors of the nasopharynx, posterior pharyngeal wall, and cervical esophagus. Treatment of the retropharyngeal node metastasis depends on the site of the primary tumor and the treatment approaches undertaken. Radiation therapy with chemotherapy is the standard treatment for both primary tumor and nodal metastasis from nasopharyngeal tumors. Surgical dissection of the retropharyngeal nodes during initial surgery should be performed in advanced tumors of the oropharynx and hypopharynx. Although retropharyngeal node dissection is technically difficult, it should be considered during the standard neck dissection by retracting the carotid artery laterally and dissecting medial to the carotid artery in the retropharyngeal area. Intensity modulated radiation therapy appears to be much more effective at rendering the appropriate dosage to this area without damaging the spinal cord. Conventional radiation therapy may underdose the retropharyngeal nodes to avoid spinal cord complications.
During primary surgery, the carotid artery is rarely an issue. Even in large tumors, most of the time the disease can be easily peeled off the carotid artery, especially with subadventitial dissection. If the soft tissues around the skin are normal, the carotid artery does not require any specific protection. It may be necessary to protect the carotid artery if there is going to be a pharyngeal suture line or pharyngeal resection. Pharyngeal fistula and salivary leak can be very detrimental to the carotid artery. The carotid adventitia may become weak and blow out. Most of the time, the issue of carotid artery resection comes in patients who are undergoing salvage surgery or who have extensive metastatic disease in the neck encircling more than 180° of the carotid. Initial clinical evaluation and imaging studies will indicate that carotid resection may be necessary for satisfactory and complete resection of the metastatic tumor in the neck. There is a very high incidence of neuromorbidity and post-
Figure 7 Patient with extensive metastatic disease; however, the tumor does not encircle the carotid artery and extends only on a 180° angle sideways. The neck dissection could be performed with sacrifice of the vagus nerve and the sympathetic trunk.
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operative mortality in patients undergoing carotid resection. The most common complication is related to neurological events such as stroke, hemiplegia, and loss of speech. Rarely, it may lead to blindness. The issue of carotid resection needs to be evaluated in the proper perspective with sound oncologic principles. If the tumor appears to be adherent to the carotid artery and resecting the carotid artery will mean a potential cure, one may consider resection and reconstruction of the carotid artery; however, this is a rare situation (Figures 6 and 7). The majority of the time when the tumor is adherent to the carotid artery, it invades the surrounding structures such as the carotid sheath, vagus nerve, phrenic, sympathetic trunk, and scaleni muscles. Unless the surgeon strongly feels that all gross tumor cannot be removed along with carotid resection, it should not be undertaken because of the very high incidence of local recurrence, overall poor prognosis, and potential complications, as well as a high incidence of neuromorbidity and mortality. Palliative carotid resection should not be considered. If there is any consideration of resecting the carotid artery, it is important to have a vascular surgeon available for reconstructing the carotid artery. The most common technique employed is the use of Gortex graft as an interposition graft. However, Gortex graft is not most suitable in patients undergoing pharyngeal resection or if there is a potential of pharyngocutaneous fistula. Under these circumstances, the saphenous vein is the best alternative.
Carotid blow Carotid rupture and carotid blow out was a common complication of head and neck surgical procedures in the 1970s and 1980s. Fortunately, this complication is currently a rare event as a result of better surgical techniques, improved radiation techniques, and the use of carotid protection with pectoralis myocutaneous flap or free flaps. Both the pectoralis myocutaneous flap and free flap protect the carotid artery with extensive soft tissue coverage. Carotid rupture is commonly noted in patients who have undergone previous radiation therapy and who have a pharyngeal leak with carotid artery bathing in the saliva. The radiation therapy leads to weakening of the carotid sheath. The carotid blow out used to be a catastrophic complication with a dire emergency. Most of the time, the bleeding can be controlled with pressure; however, the patient needs to be brought to
189 the operating room and the carotid artery ligated. This procedure has a very high complication rate related to neurological complications such as stroke and hemiplegia; there is also a high incidence of postoperative mortality. Rarely, multiply recurrent tumor may invade the carotid artery directly with necrosis of the medial border of the carotid artery, leading to extensive bleeding in the oropharyngeal area and subsequent exsanguination. However, this complication is seen very rarely today.
References 1. Shah JP: Patterns of cervical lymph node metastasis from squamous cell carcinomas of the upper aerodigestive tract. Am J Surg 160:405409, 1990 2. Shah JP, Medina J, Shaha AR, et al: Cervical lymph node metastasis. Curr Prob Surg 30:1-335, 1993 3. Kowalski LP, Medina JP: Nodal metastases: Predictive factors. Otolaryngol Clin North Am 31:621-637, 1998 4. Crile GW: Excision of cancer of the head and neck with special reference to the plan of dissection based on one hundred and thirty-two operations. JAMA 47:1780-1786, 1906 5. Martin H, DelValle B, Ehrlich H, et al: Neck dissection. Cancer 4:441-499, 1951 6. Suarez O: El problema se las metastasis linfticas y alejadas del cancer de laringe e hypopharinge. Rev Otorhinolaryngol 23:83-89, 1963 7. Byers RM, Wolf PF, Ballantyne AJ: Rationale for elective modified neck dissection. Head Neck 10:160-167, 1988 8. Byers RM: Modified neck dissection. A study of 967 cases from 1970 to 1980. Am J Surg 150:414-421, 1985 9. Shah JP: Cervical lymph node metastases: Diagnostic, therapeutic and prognostic implications. Oncology (Huntingt) 4:61-69, 1990 10. Medina JE: A rational classification of neck dissections. Otolaryngol Head Neck Surg 100:169-176, 1989 11. Robbins KT, Clayman G, Levine PA, et al: Neck dissection classification update: Revisions proposed by the American Head and Neck Society and the American Academy of Otolaryngology-Head and Neck Surgery. Arch Otolaryngol Head Neck Surg 2002;128:751-758 12. American Joint Committee on Cancer: AJCC Cancer Staging Handbook, 6th ed. New York, NY, Springer Verlag, 2002 13. Shaha AR: Extended neck dissection. J Surg Oncol 45:229-233, 1990 14. Carew JF, Spiro RH: Extended neck dissection. Am J Surg 174:485489, 1997 15. Ferlito A, Shaha AR, Rinaldo A: Retropharyngeal lymph node metastasis from cancer of the head and neck Acta Otolaryngol (Stockholm) 122:556-560, 2002 16. Gavilan J, Ferlito A, Silver CE, et al: The status of carotid resection in head and neck cancer. Acta Otolaryngol (Stockholm) 122:453-455, 2002