Otolaryngology Head and Neck Surgery

Transcription

1 Otolaryngology MARCH 1989 VOlUME 100 NUMBER 3 EDITORIAL A rational classification of neck dissections JESUS E. MEDINA. MD. Oklahoma City. Oklahoma In the past few decades, the radical neck dissection, originally described by Crile' and later popularized by Martin et al.,? has been modified in various ways, giving rise to several types of cervical lymph node dissections 3 that are currently used for the surgical treatment of the neck in patients with cancer of the head and neck region. Because ofthe number and variety of these operations, the tenn "modified neck dissection" is no longer adequate, since it is not descriptive of any one of the multiple modifications of the radical neck dissection. Other terms such asjunctional,4 conservative,s and limited 6 neck dissection are similarly nondescriptive. Their use, however, has created a state of confusion and a problem of nomenclature that can only be resolved by the development of a proper classification of neck dissection. A rational classification of neck dissections must take into account important anatomic structures that may be removed or preserved, such as the spinal accessory nerve and the internal jugular vein. However, it should primarily delineate the lymph node groups of the neck that are removed, which vary with the different neck dissections. The location and the extent of lymph node metastases in patients with squamous cell carcinoma of the upper aerodigestive tract appear to have important implications for treatment and prognosis. Furthermore, a better understanding of the distribution of lymph node From the Department of Otolaryngology. The University of Oklahoma Health Sciences Center. SUbmitted for publication Aug ; accepted Aug ! Reprint requests: Jesus E. Medina. MD. University of Oklahoma Health Sciences Center. P.O. Box Oklahoma City. OK metastases in these patients. and the combined use of surgery and radiation therapy, have led some centers to use neck dissections that selectively remove only the lymph node groups that are considered to be at high risk of containing metastases. The purpose of this article is not to debate the riskbenefit aspects of dissecting selected lymph node regions in selected patients. Some clinicians hold that such practices are not rewarded by a decrease in morbidity, and that there may be an increased risk of oncologie failure whenever the block they consider basic (i.e., the radical neck dissection) is amended. Nevertheless, few would deny that there are many variations of cervical lymphadenectomy being practiced worldwide today, and to talk about them, we need to clarify our terms. To discuss the extent of the various operations being performed and to classify them. it is essential to adopt a common nomenclature for the lymph node groups of the neck. Suen and Goepfert' and O'Brien et aj.8 em. phasized this point in their recent publications and they recommend adoption of the diagrammatic division of the lymph nodes of the neck in regions; this has been used at Memorial Sloan-Kettering Cancer Center for many years. 9 This method of grouping the lymph nodes of the neck is not only simple and refined by longstanding use, but is ideally suited as the basis for a classification of the various neck dissections that are currently being used. A diagrammatic representation of the lymph node regions is shown in Fig. I. Region I includes the contents of the submental and submandibular triangles. Regions Il, III. and IV include the lymph nodes adjacent to the internal jugular vein and the lymph nodes contained '69

2 .70 MEDINA Otolaryngology Table 1. Classification of neck dissections I A. Comprehensive Radical Modified radical Type I Type II Type III B. Selective Lateral Anterolateral (supraomohyoid) Posterolateral C Extended Fig. 1. Lymph node regions of the neck. within the fibroadipose tissue located medial to the sternocleidomastoid muscle. These are arbitrarily divided into equal thirds. Region 1/ corresponds to the upper third and includes the upper jugularand jugulodigastric nodes and the upper posterior cervical nodes, which relate to the superior portion of the spinal accessory nerve. The point at which the omohyoid muscle crosses over the internal jugular vein grossly corresponds with the line dividing regions JIJand IV. Region IV includes the lower jugular lymph nodes, as well as the scalene and the supraclavicular nodes that are located deep to the lower third of the sternocleidomastoid muscle. Region V includes the contents of the posterior triangle of the neck, which is demarcated by the posterior border of the sternocleidomastoid muscle, the clavicle, and the anterior border of the trapezius muscle. In many publications, these regions have been referred to as "levels". Since this carries a connotation of depth, stratification, or distance from the site of origin that is not intended, regions is a preferable term. Analyzing the different neck dissections in terms of the groups of lymph nodes that are removed and the neurovascular and muscular structures that are preserved, it becomes apparent that there are essentially three anatomic types of neck dissections: comprehensive, selective, and extended (Table I). Interestingly, the rationale for the development and current use of these three types of neck dissections is also different. Comprehensive neck dissections. These consist of the removal of all the lymph node regions (I through V) of one side of the neck, from the inferior border of the mandible to the clavicle, and from the anterior midline to the anterior border of the trapezius muscle (Fig. 2). Included in this category are the radical neck dissection-the basic prototype in terms of nodal resection-and those modifications of the radical neck dissection that were developed with the intention of reducing the morbidity of this operation; i.e., the shoulder disability that results from resecting the spinal accessory nerve, the cosmetic deformity caused by the removal of the sternocleidomastoid muscle, and the venous obstruction implicit in the removal of the internal jugular vein, particularly when the operation is done on both sides of the neck. By preserving one or more of these structures, such modifications of theradical neck dissection can preserve shoulder function, cosmetic appearance, and normotensive venous outflow, while still removed, comprehensively, are all the lymph node regions (I through V) of one side of the neck. These operations are truly modifications of the original radical neck dissection. Thus, it is appropriate to refer to them as Modified Radical Neck Dissections. The three neck dissections that can be included in this category are outlined in Table 2. They differ from each other only in the number of neural, vascular, and muscular structures that are preserved (Fig. 3). Therefore, they can be subclassified into a Type I, in which only one structure, the spinal accessory nerve, is preserved; 10 Type 1/, in which two structures, the spinal accessory nerve and the internal jugular vein, are preserved;" and Type 1/1, in which all three structures, the spinal accessory nerve, the internal jugular vein, and the sternocleidomastoid muscle are preserved. This last neck dissection corresponds to the "functional neck dissection" popularized by Bocca et at. 4 and recently called "anterior and lateral modified neck dissection" by Lingeman and Shellhamer." In a technical variant of this operation described by Marchetta et ai. IJ the ster-

3 Volume 100 Number 3 March 1989 Rational classification of neck dlsecttons 171 Fig. 2. A, Comprehensive neck dissection; B. radical neck dissection. nocleidomastoid muscle is detached from the sternum and the clavicle, retracted superiorly, and replaced after the lymph node-bearing tissues have been removed. In yet another technical variant, the contents of the posterior triangle of the neck are removed from an anterior approach, retracting the sternocleidomastoid muscle and dividing the cutaneous branches of the cervical plexus. IS Bocca and Pignataro" and Joseph et a I.': di 10 reate that the nodes in the submandibular and submental triangles (Region l) need to be removed only when the primary tumor is located in the oral cavity. Interestingly, in clinical practice the other two types of modified radical neck dissection and even the radical neck dissection are often modified by leaving these node groups undisturbed. We must, therefore, recognize a subcategory of radical and modified radical neck dissections in which the Region I lymph nodes are not removed. These operations can be simply distinguished from their counterpart in which the Region I nodes are removed by designating them as subtype B and subtype A, respectively (Table 2). Selective neck dissections. These dissections, on the other hand, consist of the selective en bloc removal of only the lymph node groups that-depending upon the location of the primary tumor-are most likely to contain metastases. Although preservation of function Table 2. Comprehensive neck dissection Type of Lymph node Structure. dl..ectlon group. removed preserved Radical Subtype A I-V Subtype B II-V Modified radical Type I A I-V Type I B II-V SAN Type II A I-V Type II B II-V SAN,IJV Type III A I-V Type III B II-V SAN, IJV, SCMM SAN, Spinal accessory nerve; IJV, internal jugular vein; SCMM, sternocleidomastoid muscle and cosmesis were also primary goals in the development of these operations, their current use is based on the concept that removal of all the lymph groups of one or both sides of the neck is not always necessary, and that the en bloc removal of the nodal groups at highest risk for metastases has the same therapeutic value and provides the surgeon with the same information needed for individual treatment planning as the more extensive radical and modified radical neck dissections

4 172 MEDINA Otolaryngology Type I Type n Type m Fig. 3. Modified radical neck dissections.

5 Volume 100 Number 3 Motch1989 Raffonal classification of neck dlsecllons.71 Fig. 4. Lateral neck dissection. Since it appears that the addition of postoperative radiation therapy improves regional tumor control when multiple lymph node metastases or extracapsularspread of tumor are demonstrated histologically.3.9 a selective neck dissection can-in selected patients-provide this valuable staging information without compromising cancer control and with minimal morbidity The concept of selective node dissection is based on a number of anatomic and clinical observations that indicate that the lymphatic drainage of the skin and mucosal surfaces of the head and neck follows predictable routes and that the distribution of lymph node metastases is. likewise. predictable in the previously nondisturbed or untreated neck.":" For example. the submandibular and submental lymph nodes (Region l) are rarely, if ever, involved in patients with tumors of the larynx or hypopharynx. These node groups. on the other hand. constitute the primary echelon of lymphatic drainage and must be removed when the primary tumor is located in the oral cavity. In both instances. metastases are rarely present in the nodes of the posterior triangle of the neck (Region V), particularly in the absence of clinically obvious metastases in the jugular lymph node groups There are three different neck dissections that can be included in the category of Selective Neck Dissections (Table 3): Fig. 5. Antero-Iateral neck dissection. 1. Lateral neck dissection. This consists of the en bloc removal of the upper (Region II). middle (Region III). and lower (Region IV) jugular lymph node groups (Fig. 4). The posterior limit of the dissection is marked by the cutaneous branches of the cervical plexus as they cross over the posterior border of the sternocleidomastoid muscle. This type of neck dissection is advocated by some surgeons for the elective treatment of the neck in patients with tumors of the pharynx and larynx." Since these tumors rarely metastasize to the nodes of the submental, submandibular, and posterior triangles of the neck, these nodal groups are not removed. This type of dissection has previously been called "anterior neck dissection" by Jesse et al. 22 and Byers.' However. the term lateral is anatomically more appropriate since, in a cross-section of the neck, the lymph nodes and soft tissues removed by this operation are located in the lateral and not in the anterior aspect of the neck. 2. Antero-lateral neck dissections. This category comprises two neck dissections: the supraomohyoid neck dissection and the expanded supraomohyoid neck dissection or anterolateral neck dissection proper (Fig. 5). In both operations, the contents of the submental and submandibular tri-

6 174 MEDINA Otolaryngology Table 3. Selective neck dissection Type of dissection Lateral Antero-Iateral Supraomohyoid Postero-Iateral Radical Type I Type II Type III Lymph node groups removed II-Ill-IV I-IV I-III II-V Suboccipital and retroauricular StNctures preserved SAN, IJV, SCMM SAN. IJV, SCMM SAN. IJV. SCMM None SAN SAN.IJV SAN. IJV. SCMM SAN. Spinal accessory nerve; IJV. internal jugular vein; SCMM, sternocleidomastoid muscle Fig. 6. Postero-Iateral neck dissection. angles (Region I) and the upper (Region II) and midjugular (Region III) lymph node groups are removed en bloc.' The expanded supraomohyoid dissection includes, in addition. the lower jugular lymph nodes (Region IV).17 The posterior limit of both dissections is also marked by the cutaneous branches of the cervical plexus and the posterior border of the sternocleidomastoid muscle. The inferior limit of the supraomohyoid neck dissection is the omohyoid muscle as it crosses the internal jugular vein, whereas the inferior limit of the expanded supraomohyoid dissection is the clavicle (Figure 5). The latter neck dissection is the operation that Ballantyne!' has performed for many years, but has only recently described as "the modified neck dissection." This operation has also been called "anterior modified neck dissection. "12 An increasing number of head and neck surgeons are using these neck dissections for the elective treatment of the neck in patients with cancer of the oral cavity Postero-lateral neck dissection. This is the only dissection in which the suboccipital and retroauricular lymph node groups are removed. Also included in this dissection are the upper (Region 11), middle (Region III), and lower (Region IV) jugular lymph nodes, and the nodes in the posterior triangle of the neck (Region V) (Fig. 6). This operation is used for the surgical treatment of the regional lymph nodes in patients with primary cutaneous malignant melanoma. squamous cell carcinoma. and other neoplasias of the skin of the posterior aspect of the scalp and neck In the original technique, described by Rochlin" in the spinal accessory nerve, the internal jugular vein, and the sternocleidomastoid muscle are preserved. However, depending upon the clinical situation. removal of one or more of these structures may be indicated." Therefore. like the comprehensive neck dissections, the posterolateral neck dissection can be subclassified as Radical Postero-lateral Neck Dissection when the spinal accessory nerve. the internal jugular vein, and the sternocleidomastoid muscle are removed, Postero-lateral Type I when only the spinal accessory nerve is preserved, Postero-lateral Type /I when the spinal accessory nerve and the internal jugular vein are preserved. and Postero-lateral Type 1/1 when the spinal accessory nerve, the internal jugular vein, and the sternocleidomastoid muscle are preserved (Table 3). It must be emphasized that some boundaries of the selective neck dissections are not objectively delineated by anatomic landmarks. As a result, the extent of these operations may be subject to the judgement and experience of the surgeon and, thus, difficult to standardize. For example, considerable variations can occur in the posterior extent of the lateral and anterolateral neck dissections, since nodes from the posterior triangle level (Region V) may be variably removed through the spaces between the branches of the cervical plexus and in the lower neck, where the cutaneous branches of the plexus no longer cross forward over the posterior border of the sternocleidomastoid muscle. In contrast, the boundaries of the comprehensive neck dissections are anatomically well defined-i.e., the anterior border of the trapezius. the clavicle, and the inferior border of

7 Volume 100 Number 3 March 1989 Rational classification of neck dlsectlons 175 Fig. 7. Upper-lateral neck dissection. Fig. 8. Lower-lateral neck dissection. the mandible. This makes these operations easier to reproduce. Although it is tempting to include the so-called upper and lower neck dissections' in the category of selective neck dissections. it seems more appropriate to refer to these procedures as regional node dissections and not as neck dissections. for they. in fact, consist of the removal of the lymph nodes in one nodal region of the neck. However. in keeping with the nomenclature used for the classification of neck dissections, these procedures would be designated as upper lateral node dissection and lower lateral node dissection. The upper-lateral node dissection consists of the removal of the upper jugular nodes and the lymph nodebearing tissues located posterior to the internal jugular vein and medial to the upper third of the sternocleidomastoid muscle (Region II) (Fig. 7). This type of regional node dissection is advocated by some surgeons as a staging procedure in patients with tumors of the parotid gland The lower-lateral node dissection consists of the selective removal of the lower jugular lymph node group and the node-bearing tissues located posterior to the internal jugular vein and medial to the inferior one third of the sternocleidomastoid muscle; i.e. the scalene nodes and the most medial supraclavicular nodes (Region IV). Also included in the dissection may be the lymph node-bearing tissues of the lower third of the posterior triangle of the neck (Fig. 8). This type of node dissection is occasionally performed in patients with differentiated thyroid carcinoma who have nodal metastases in this region of the neck.':" Extended neck dissections. These dissections address the realization that several lymph node groups in the neck are not routinely removed when a radical or any other type of neck dissection is performed. These are the preauricular and intraparotid lymph nodes, the retropharyngeal, the paratracheal, and the pretracheal lymph nodes. Any of the neck dissections described here can be extended to include one or more of these lymph node groups. To develop a classification that is inclusive of all the possible resulting combinations may be impractical. But when a neck dissection is extended to include these lymph node groups, it would seem appropriate to designate the neck dissection as extended, according to the criteria proposed here, and to list the additional lymph node groups removed. For example. one may perform an extended right radical neck dissection with retropharyngeal and paratracheal node dissection. or extended right lateral neck dissections with paratracheal and pretracheal node dissection. Any individual technique of neck dissection should be designated with the generic term "neck dissection", rather than calling it a modified neck dissection or modified radical neck dissection. Such operations should be described by listing the lymph node levels that are removed and the relevant anatomic structures that are resected. as well as those that are preserved. For ex-

8 176 MEDINA Otolaryngologv ample. O'Brien et al. 8 recently described a neck dissection that is used at the University of Alabama Hospitals. It consistsof the removal of lymph node regions I through IV and the internal jugular vein. while the spinal accessory nerve and the sternocleidomastoid muscle are preserved. Any other individual technique of cervical lymphadenectomy should be described in this fashion. Standardization of nomenclature and a proper classification of neck dissections would, undoubtedly. facilitate interinstitutional communication, as well as the evaluation and reporting of treatment results. when a given type ofneck dissection is performed. Establishing clear criteria to define the validity of different types of neck dissection would also be useful in the planning of clinical trials, and in the evaluation of quality control of both clinical practices and clinical trials that involve surgical treatment of the neck in head and neck cancer patients. Obviously, givinga name to an operationdoes not obviate the need for proper documentation of a surgical procedure. The written report of an operation should indicate clearlythe lymph node regions that were removed. and the anatomic structures that were preserved. Furthermore. the written report of thepatholagist should reflect the surgeon's report in terms of the lymph node regions that were identified and examined histologically. This can only be accomplished through education of surgeons in training and communication with the pathologist. The pathologist must have a working knowledge of the classification of neck dissections surgeons perform and. more importantly. of the lymph node regions of the neck that are the basis for it. The surgeon, on the other hand. must consistently mark the surgical specimen. orient it for the pathologist, and identify the lymph node regions to be examined histologically. Only then may nomenclature and criteria bring forth the information about a neck dissection that is essential for individual patient treatment planning, the evaluation oftreatment results, and the overall quality control for patients afflicted with head and neck cancer. REFERENCES l. Crile G. Excision of cancer of the head and neck with special reference to the planof dissection baseduponone hundred thirtytwo operations. JAMA 1906;47: MartinHE, Del Valle B, EhrlichH. CahanWO. Neckdissection. Cancer 1951;4: Byers RM. Modified neckdissection: a study of 967 cases from 1970 to Am J Surg 1985;150: Bocca E, Pignataro0, Sasaki CT. Functional neck dissection: a description of operative technique. Arch Otolaryngol Head Neck Surg 1980;106: Skolnik EM, DeutschEC. Conservative neck dissection. J Laryngol 0101 (Suppl) 1983;8: Thrkula LD, Woods le. Limited or selective nodal dissection for malignant melanoma of the head and neck. Am J Surg 1984;148: Suen JY. Goepfert H. Editorial: standardization of neck dissection nomenclature. Head Neck Surg 1987;10: O'Brien CJ, Urist MM, Maddox WA. Modified radical neck dissection: terminology, technique, and indications. Am J Surg 1987;153: ShahJP, StrongE, SpiroRH. VikramB. Neckdissection: current status and future possibilities. Clin Bull 1981;11: Roy PH. Beahrs OH. Spinal accessory nerve in radical neck dissections. Am J Surg 1969;118: Sobol S. Jensen C, SawyerW. Costiloe P. Thong N. Objective comparison of physicaldysfunction after neck dissection. Am J Surg 1985;150: Lingeman RE, ShellhamerRH. Surgicalmanagement of tumors of the neck. In: Thawley SE, Panje WR. eds. Comprehensive management of head and neck tumors. Vol. 2. Philadelphia: W.B. Saunders Company, 1987: Marchetta FC, Sako K. Matsurra H. Modified neck dissection for carcinoma of the thyroid gland. Am J Surg 1970;120: BoccaE. PignataroO. A conservationtechnique in radicalneck dissection. Ann 0101 Rhinol Laryngol 1967;76: IS. JosephCA. Gregor RT.Davidge-Pitts KJ. The roleof functional neck dissection in the management of advanced tumors of the upper aerodigestive tract. S Afr J Surg 1985;23: ByersRM. WolfPF, Ballantyne AJ. Rationale for electivemodified neck dissection. Head Neck Surg 1988;10: Medina JE, Byers RM. Supraomohyoid neck dissection: rationale. indications, and surgical technique. Head Neck Surg 1989;11: Rouviere H. Anatomy of the human lymphatic system. Ann Arbor, Michigan: EdwardBrothers Inc., Fisch UP. Sigel ME. Cervical lymphatic system as visualized by lymphography. Ann 0101 Rhinol Laryngol 1964;73: LindbergR. Distribution of cervicallymphnodemetastases from squamous cell carcinomaof the upper respiratory and digestive tracts. Cancer 1972;29: SkolnikEM. The posteriortrianglein radicalnecksurgery. Arch Otolaryngol Head Neck Surg 1976;102: Jesse RH, Ballantyne AJ, Larson D. Radical or modified neck dissection: a therapeutic dilemma. Am J Surg 1978;136: Ballantyne AJ. Classical and functional neckdissection. In: Ariyan S. ed. Cancer of the head and neck. St. Louis: The C.V. Mosby Company, 1987: SpiroJD. Spiro RH, ShahJP, SessionsRB. StrongEW. Critical assessment of supraomohyoid neckdissection. Am J Surg 1988; 156: Goepfert H. Jesse RH. Ballantyne AJ. Posterolateral neck dissection. Arch Otolaryngol Head Neck Surg 1980;106: de LangenZl, Verrney A. Posterolateral neck dissection. Head Neck Surg 1988;10: Rochlin DB. Posterolateral neck dissection for malignant neoplasms. Surg Gynecol Obstet 1962;115: Ballantyne AJ. Modified neck dissection. In: Jackson I, Sommerlad B, eds. Recent advances in plastic surgery. New York: Churchill Livingstone Publishers, 1985: Byers RM. Treatment of malignant tumors of the parotid and submaxillary glands. Res Staff Physic 1982;28: Conley J. Tinsley PP. Treatment and prognosis of mucoepidermoid carcinoma in the pediatric age group. Arch Otolaryngol Head Neck 8urg 1985;111:322-4.