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Modified radical neck dissection
HOW I DO IT
Modified Radical Neck Dissection Terminology, Technique, and Indications
Christopher J. O’Brien, MS, FRACS, Marshall M. Urlst, MD, FACS, and William A. Maddox, MD, FACS, Birmingham, Alabama
Classical radical neck dissection is usually regarded as the operation of choice when cervical lymph nodes are clinically involved by metastatic squamous carcinoma of the upper aerodigestive tract. This procedure is oncologically effective but is also disfiguring and disabling because it entails removal of the sternocleidomastoid muscle and sacrifice of the spinal accessory nerve. Removal of the ipsilateral internal jugular vein during radical neck dissection causes little morbidity, but bilateral excision of the internal jugular vein is associated with marked facial and cerebral swelling. Modifications to the classic operation were described by Bocca and Pignataro [1,2] in the mid 1960s. Around that time, Ballantyne, of the M.D. Anderson Hospital in Houston, also proposed a less radical form of neck dissection, although he did not publish his technique. All of these procedures were aimed at effectively removing the lymphatic glands of the neck, while reducing morbidity by preserving the sternocleidomastoid muscle, the spinal accessory nerve, and the internal jugular vein. Terminology
In the last two decades, less than radical neck dissections have been widely performed; however, the terminology applied to these operations has been loose and confusing. This reflects the large number of operations that are classified as modified radical neck procedures. Bocca’s [I] initial report From the Section of Surgical Oncology, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama. Requests for reprints should be addressed to William A. Maddox, MD, Section of Surgical Oncology. Department of Surgery, University of Alabama at Birmingham, University Station, Birmingham, Alabama 35294.
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described the use of a “functional” neck dissection in combination with supraglottic laryngectomy. However, in subsequent descriptions of their operative technique, Bocca et al [2,4] have used the terms “conservative” neck dissection and “functional” neck dissection. In this procedure, all node-bearing areas, including the posterior triangle, are removed, although dissection of the submandibular triangle is not routinely carried out. The contents of the posterior triangle are dissected directly and passed anteriorly under the retracted sternocleidomastoid muscle, which is preserved. The spinal accessory nerve, internal jugular vein, cervical plexus, greater auricular nerve, and tail of the parotid gland are all preserved also. In a report from the M.D. Anderson Hospital, Jesse et al [3] described three procedures that they used since 1970. They were all called “functional” neck dissections. The functional dissection for oral cavity and oropharyngeal primary tumors removed submaxillary, jugulodigastric, and upper and midjugular groups of nodes, whereas the functional operation for patients with cancer of the supraglottic larynx included bilateral removal of jugulodigastric and upper, middle, and lower jugular nodes. The third procedure was actually a radical neck dissection in which only the spinal accessory nerve was spared. A more recent report from M.D. Anderson Hospital described a series of 1,372 modified neck dissections, which included “anterior” or “modified,” “ posterior,” “lower,” “functional,” “suprahyoid,” and “supraomohyoid” neck dissections [5]. In 1983, Suen and Wetmore [6] described an operation that they called a “modified neck dissection (conservation or functional).” This procedure was
The American Journal of Surgery
Modified Radical Neck Dissection
Figure 1. The five major lymph node levels are shown In addition to the important anatomic landmarks of the neck.
essentially the same as that proposed by Ballantyne and differed from the Bocca operation only insofar as the posterior triangle dissection was carried out from an anterior approach under the retracted sternocleidomastoid muscle. They also described “regional” neck dissection, which was also termed “selective” and “partial.” This operation referred to removal of a group or groups of nodes, for example, submandibular triangle and jugulodigastric node dissection, or interjugular node dissection. Also in 1983, Calearo and Teatini [7] described a procedure that was similar to that of Bocca and was also called a “functional” neck dissection. It differed from Bocca’s operation only in that the lower pole of the parotid gland was removed and cervical roots 3 and 4 were divided. These reports show that the terms applied to the various modifications of neck dissection are too numerous and vague. No term is specific enough to reliably designate a particular procedure without further definition. Simply calling a neck dissection “functional” or “conservative” is inadequate because these terms may mean different things to different people. More anatomically specific terms like “supraomohyoid” and “suprahyoid” remain in usage, but these are also open to abuse and are sometimes used interchangeably [8]. All of these terms do not need to be redefined; instead, they should be replaced with a simple descriptive system that avoids ambiguity and allows clear definition of
Volume 153, March 1987
which node groups are dissected and which structures are preserved. The system of nomenclature for the major lymph node groups used at Memorial Hospital, New York for many years is a sound basis for such a descriptive system [9]. The node groups are depicted in Figure 1. Level I contains nodes of the submandibular and submental triangles. Levels II, III, and IV contain nodes of the upper, middle, and lower jugular chain that lie deep to the sternocleidomastoid muscle which is divided into thirds. Level II also contains the jugulodigastric node and the upper spinal accessory or upper posterior cervical nodes. The point at which the omohyoid muscle crosses deep to the sternocleidomastoid muscle is a landmark that could be used to separate levels III and IV. The juguloomohyoid nodes, therefore, lie at the lower end of level III. Level IV contains mainly lower jugular nodes, but supraclavicular nodes are also present in this region deep to the sternocleidomastoid muscle and medial to the brachial plexus. Level V refers to the contents of the posterior triangle which include mid and lower spinal accessory nodes and transverse cervical nodes. The Memorial Hospital system of nomenclature includes a level VI, comprising nodes around the thyroid gland, and a level VII, comprising nodes of the tracheoesophageal groove and superior mediastinum. There are practical advantages to considering lymph node groups according to the regions in
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TABLE I
Classification of Varlous Modified Neck Dissections According to the Levels Dissected and Structures Preserved Reference
Type of Neck Dissection
1
Bocca & Pignataro [2]
Conservation
Bocca et al [ 41 Jesse et al [ 3]
Functional Functional
Byers [5]
Suprahyoid Supraomohyoid Anterior or modified Posterior Lower Functional Modified (conservative or functional) Regional (selective or partial)
Suen & Wetmore
161
Brown & McDowell [ 81 Calearo 8. Teatini [ 71
Supraomohyoid Functional
Structures Preserved
Levels Dissected
II-V (&I) I-III II-IV I-V
II
11-111 II-IV II B v IV a v I-V II-V (fl)
Variable, for example I & II, bilateral VII I-III II-V
SCM, IJV, SAN, CP, omohyoid tail of parotid, submaxillary gland SCM, SAN, 8, IJV SCM, SAN, & IJV SAN unless invaded Not specified but principally SCM, SAN, & IJV
SCM, IJV, SAN & CP, 8 omohyoid Not specified
SCM, IJV, SAN SCM, IJV, SAN
CP = cervical plexus; IJV = internal jugular vein; SAN = spinal accessory nerve; SCM = sternocleidomastoid
which they are found. Although anatomists give names to certain groups of nodes (for example, jugulodigastric, juguloomohyoid, and spinal accessory nodes), these nodes are removed by dissection of anatomic zones and are not readily identifiable as discrete structures, especially when a large metastatic mass is present. This is especially true of level II, which contains several named lymph nodes or node groups and is the region most frequently involved by oral and oropharyngeal cancers. Using this system of nomenclature, Bocca’s operation is a modified neck dissection encompassing levels II through V and preserving the sternocleidomastoid muscle, internal jugular vein, spinal accessory nerve, cervical plexus, and tail of the parotid gland. Sometimes level I is also included, in which case the submandibular salivary gland is spared. Similarly, the operations of Suen and Wetmore [6], Calearo and Teatini [ 71, and those used at the M.D. Anderson Hospital [3,5] could be concisely described according to the node levels dissected and which structures are preserved. Table I summarizes some of these procedures giving the name of the operation used by each author and the translation into the suggested system. We do not suggest that the term “radical neck dissection” be replaced if it specifically refers to the classic procedure described by Crile [IO] and subsequently advanced by Martin et al [11] and Beahrs [12]. Radical neck dissection in which only the spinal accessory nerve is preserved [13] is quite unambiguous but, for consistency, could be designated a modified dissection of levels I through V sparing the spinal accessory nerve.
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muscle.
Technique Modified radical neck dissections have been carried out at the University of Alabama Hospitals since 1979. The technique described was developed by the senior author (WAM) and encompasses levels I through IV sparing the sternocleidomastoid muscle, the spinal accessory nerve, and the cervical plexus. The submental triangle is not dissected unless indicated. The internal jugular vein is usually removed in this technique unless a bilateral procedure is carried out, in which case the vein on the side opposite the tumor is spared. Level V is not dissected. The ,posterior limit of the dissection is approximately the posterior border of the sternocleidomastoid muscle. Dissection of the contents of the posterior triangle is not included in this procedure, since lymph nodes in this region are rarely involved by metastatic disease arising from a primary site in the oral cavity, oropharynx, larynx, or hypopharynx (5,141. Furthermore, metastases to the posterior triangle in the absence of involvement of the jugular chain nodes are uncommon [15]. However, if the posterior triangle is to be dissected, we believe the cervical plexus should be sacrificed to facilitate better clearance of this region. The technique is illustrated in Figures 2 through 7.
Comments
Our clinical experience with the modified radical neck dissection described is reported elsewhere [26]. On the basis of this experience and that of other investigators, we believe this operation is appropriate as an elective procedure among patients with epidermoid carcinoma of the upper aerodigestive tract under the following circumstances: (1) When
The American Journal of Surgery
Modified Radical Neck Dissection
Ftgure 2. Inset: The incision preferred by the senior author is shown by the solid line. A useful alternattve is shown by the broken line. Main figure: The flaps have been elevated deep to the p/atysma, preserving the great aurlcular and marginal mandibular nerves. The broken line shows the line along which the fascia investing the sternocleidomastotd muscle will be incised.
Figure 3. The fascia investing the sternocleidomastoid muscle has been incised and elevated from this muscle by sharp dissection. The greater auricular nerve is mobilized, retracted posteriorly, and preserved. The la// of the parotid gland is also preserved but should be removed if the primary tumor involves the skin of the face or lip.
Volume 153, March 1997
Figure 4. The investing layer of fascia has been dissected from the lateral, anterior, and deep aspects of the sternocleldo mastoid muscle. Posteriorly, this dissection is tlmtted by the branches of the cervical plexus crossing from the floor of the posterior triangle to the posterior border of the retracted sternocletdomastold muscle. The anterior be//y of the omohyold muscle is identified and divided, a/towing the posterior belly to retract deep to the sternocleldomastoid muscle. The sptnal accessory nerve, with its branch to the sternocteldomastold muscle, is located on the deep surface of the upper end of the sternocleidomastoid muscle.
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Figure 5. The main dissection is commenced at the lower end of the retracted sternocieidomastoid muscle and carried superiorly with scalpel or scissors. The lower end of the internal jugular vein is doubly ligated, and the usual care to Identify the thoracic duct is taken. This part of the procedure differs from standard radical neck dissection only in that the cervical plexus is preserved. The internal jugular vein may be preserved on one side in synchronous bilateral procedures.
Figure 6. As the dissection is carried superiorly, the attachment of the omohyoid muscle to the hyoid bone is divided, and the carotid bifurcation and hypogiosseal nerve are identified. The posterior belly of the d/gastric muscle is defined and retracted superiorly, whereas the upper end of the sternocleidomastold muscle, along with the spinal accessory nerve and the greater auricular nerve, is retracted posterloriy. This allows clean dissection of level II commencing posteriorly and moving anteriorly. The proximal end of the internal jugular vein is identified, ligated, and divided as close to the jugular foramen as possible.
local disease is advanced and there is a high probability of clinically uninvolved nodes containing occult metastatic disease-that is, in patients with TS or T4 cancers of the oral cavity, oropharynx, supraglottic larynx, and hypopharynx. (2) When resection of the primary tumor is carried out through a neck incision and the possibility of nodal metastases is high. This includes patients with earlyoropharyn-
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geal, supraglottic laryngeal, and hypopharyngeal tumors but not patients with glottic primary tumors, since they rarely metastasize to the neck unless advanced. If postoperative radiotherapy is planned for the primary site and the neck is clinically uninvolved and does not need to be entered to carry out the resection, for example, in the case of a large oral
The American Journal of Surgery
Modified Radical Neck Dissection
I
Cemtkl A.
Figure 7. The dlssectlon continues in an anterior dtrectlon, removing the contents of the submandibular triangle, including the sallvary gland. By maintaining a plane supertlcial to the superior thyroid artery, damage to the superior laryngeal nerve Is avoided. The neck structures at the completion of dissection are seen.
primary tumor, it may be equally appropriate to electively irradiate the neck along with the primary site rather than perform a modified neck dissection. Because there is a high likelihood of recurrence in the neck when patients with clinically papable nodes are treated by this operation [16], we believe it should be a therapeutic procedure only when there is minimal nodal disease, that is, N1 according to the guidelines of the American Joint Committee on Cancer, 1983 (see Table II), or when the disease is staged NZ by virtue of bilaterality (N& or contralaterality (Ns,.). We believe these patients can be treated according to the assessment of each side of the neck. Patients with bilateral or contralateral N1 disease could therefore have the modified radical neck dissection just described. If more extensive disease is encountered during the procedure a radical neck dissection should be performed, although the spinal accessory nerve could still be preserved in some cases. It is our practice to treat patients with histologically involved lymph nodes with postoperative radiotherapy if there is more than one involved node or evidence of extracapsular spread of metastatic disease. We do not believe that the procedure is appropriate for patients with multiple clinically palpable nodes (Nsb), for those with a clinically palpable node larger than 3 cm in diameter (Nza or N&, for patients with clinical involvement of the posterior triangle, or for patients in whom radiotherapy to the neck has failed. Summary
The terminology relating to the various modifications of radical neck dissection is loose and confusing. A simple system of nomenclature has been sug-
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internalJu@utarK (ligatedlowfrrsnd)
TABLE II
Stage Nx No NI N2
NPZI Nzb N3 N3a
N3b
N3c
Cllnlcal Staging System for Cervical Nodes (American Joint Committee on Cancer, 1983) Description
Minimum requirements to assess the regional nodes cannot be met. No clinically involved node. Single clinically involved homolateral node 3 cm or less in diameter. Single clinically involved homolateral node more than 3 cm but not more than 6 cm in diameter, or multiple clinically involved homolateral nodes, none more than 6 cm in diameter. Single clinically positive homolateral node more than 3 cm but not more than 6 cm in diameter. Multiple clinically involved homolateral nodes, none more than 6 cm in diameter. Massive homolateral node(s), bilateral nodes, or contralateral node(s). Clinically involved homolateral node(s), one more than 6 cm in diameter. Bilateral clinically involved nodes (in this situation, each side of the neck should be staged separately; that is, NSb; right, NPa; left, NT). Contralateral clinically involved node(s) only.
gested which allows specification of the node levels dissected and the structures preserved. A technique of modified neck dissection, which excludes dissection of the posterior triangle and spares the sternocleidomastoid muscle and spinal accessory nerve, has been described. We believe this operation is appropriate when local disease is advanced and clinically uninvolved neck nodes are likely to harbor occult metastatic disease, when resection of the primary tumor is through the neck, or when clinical disease in the neck is minimal. Patients with multi-
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ple palpable nodes, patients with nodes larger than 3 cm in diameter, patients with disease in the posterior trialigle, and patients in whom radiotherapy to the neck has failed may be better served by radical neck dissection. Acknowledgment: We gratefully acknowledge the outstanding work of Samuel K. Collins, MS, AMI, medical illustrator, Birmingham, trations.
Veterans Alabama,
Administration Medical Center, for preparing the operative illus-
7.
8.
9.
10.
References
11.
1. Bocca E. Supraglottic laryngectomy and functional neck dis-
12.
2.
3.
4.
5. 6.
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section. J Laryngol 1966; 80: 831-8. Bocca E, Pignataro 0. A conservation technique in radical neck dissection. Ann Otol Rhino1 Laryngol 1967; 76: 97% 87. Jesse RH, Ballantyne AJ, Larson 0. Radical or modified neck dissection: a therapeutic dilemma. Am J Surg 1978; 136: 516-9. Bocca E, Pignataro 0, Sasaki CT. Functional neck dissection. A description of operative technique. Arch Otolaryngol 1980; 106: 526-7. Byers RM. Modified neck dissection. A study of 967 cases form 197.0 to 1980. Am J Surg 1985; 150: 414-21. Suen JY, Wetmore SJ. Cancer of the neck. In: Suen JY, Myers
13. 14.
15.
16.
EN, eds. Cancer of the head and neck. New York: Churchill Livingstone, 198 1: 200-7. Calearo CV, Teatini G. Functional neck dissection. Anatomical grounds, surgical technique, clinical observations. Ann Otol Rhino1 Laryngol 1983; 92: 215-22. Brown JB, McDowell F. Operative technique of bilateral upper dissection (supra-omohyoid dissection). In: Neck dissections. Springfield, IL: Charles C Thomas, 1954: 74-80. Shah JP, Strong E, Spiro RH, Vikram B. Neqk dissection: current status and future possibilities. Clin Bull 1981; 11: 25-33. Crile G. Excision of cancer of the head and neck with special references to the plan of dissection based on one hundred and thirty-two operations. JAMA 1906; 47: 1780-6. Martin H, Del Valle B, Ehrlich H, Cahan WG. Neck dissection. Cancer 1951; 4: 441-99. Beahrs CH, Gossel JD, Hollinshead WH. Technique and surgical anatomy of radical neck dissection. Am J Surg 1955; 90: 490-516. Roy PH. Beahrs OH. Spinal accessory nerve in radical neck dissections. Am J Surg 1969; 118: 800-4. Lindberg R. Distribution of cervical lymph node metastases from squamous cell carcinoma of the upper respiratory and digestivws tracts. Cancer 1972; 29: 1446-g. Mantravadl R, Katz A, Haas R, et al. Radiation therapy for subclinical carcinoma in cervical lymph nodes. Arch Otolaryngol 1982; 108: 108-11. O’Brien CJ, Smith JW, Urfst MM.’ Maddox WA. Is modified radical neck dissection only a staging procedure? Cancer 1987 (in press).
The American Journal of Surgery
Modified Radical Neck Dissection Terminology, Technique, and Indications
Christopher J. O’Brien, MS, FRACS, Marshall M. Urlst, MD, FACS, and William A. Maddox, MD, FACS, Birmingham, Alabama
Classical radical neck dissection is usually regarded as the operation of choice when cervical lymph nodes are clinically involved by metastatic squamous carcinoma of the upper aerodigestive tract. This procedure is oncologically effective but is also disfiguring and disabling because it entails removal of the sternocleidomastoid muscle and sacrifice of the spinal accessory nerve. Removal of the ipsilateral internal jugular vein during radical neck dissection causes little morbidity, but bilateral excision of the internal jugular vein is associated with marked facial and cerebral swelling. Modifications to the classic operation were described by Bocca and Pignataro [1,2] in the mid 1960s. Around that time, Ballantyne, of the M.D. Anderson Hospital in Houston, also proposed a less radical form of neck dissection, although he did not publish his technique. All of these procedures were aimed at effectively removing the lymphatic glands of the neck, while reducing morbidity by preserving the sternocleidomastoid muscle, the spinal accessory nerve, and the internal jugular vein. Terminology
In the last two decades, less than radical neck dissections have been widely performed; however, the terminology applied to these operations has been loose and confusing. This reflects the large number of operations that are classified as modified radical neck procedures. Bocca’s [I] initial report From the Section of Surgical Oncology, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama. Requests for reprints should be addressed to William A. Maddox, MD, Section of Surgical Oncology. Department of Surgery, University of Alabama at Birmingham, University Station, Birmingham, Alabama 35294.
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described the use of a “functional” neck dissection in combination with supraglottic laryngectomy. However, in subsequent descriptions of their operative technique, Bocca et al [2,4] have used the terms “conservative” neck dissection and “functional” neck dissection. In this procedure, all node-bearing areas, including the posterior triangle, are removed, although dissection of the submandibular triangle is not routinely carried out. The contents of the posterior triangle are dissected directly and passed anteriorly under the retracted sternocleidomastoid muscle, which is preserved. The spinal accessory nerve, internal jugular vein, cervical plexus, greater auricular nerve, and tail of the parotid gland are all preserved also. In a report from the M.D. Anderson Hospital, Jesse et al [3] described three procedures that they used since 1970. They were all called “functional” neck dissections. The functional dissection for oral cavity and oropharyngeal primary tumors removed submaxillary, jugulodigastric, and upper and midjugular groups of nodes, whereas the functional operation for patients with cancer of the supraglottic larynx included bilateral removal of jugulodigastric and upper, middle, and lower jugular nodes. The third procedure was actually a radical neck dissection in which only the spinal accessory nerve was spared. A more recent report from M.D. Anderson Hospital described a series of 1,372 modified neck dissections, which included “anterior” or “modified,” “ posterior,” “lower,” “functional,” “suprahyoid,” and “supraomohyoid” neck dissections [5]. In 1983, Suen and Wetmore [6] described an operation that they called a “modified neck dissection (conservation or functional).” This procedure was
The American Journal of Surgery
Modified Radical Neck Dissection
Figure 1. The five major lymph node levels are shown In addition to the important anatomic landmarks of the neck.
essentially the same as that proposed by Ballantyne and differed from the Bocca operation only insofar as the posterior triangle dissection was carried out from an anterior approach under the retracted sternocleidomastoid muscle. They also described “regional” neck dissection, which was also termed “selective” and “partial.” This operation referred to removal of a group or groups of nodes, for example, submandibular triangle and jugulodigastric node dissection, or interjugular node dissection. Also in 1983, Calearo and Teatini [7] described a procedure that was similar to that of Bocca and was also called a “functional” neck dissection. It differed from Bocca’s operation only in that the lower pole of the parotid gland was removed and cervical roots 3 and 4 were divided. These reports show that the terms applied to the various modifications of neck dissection are too numerous and vague. No term is specific enough to reliably designate a particular procedure without further definition. Simply calling a neck dissection “functional” or “conservative” is inadequate because these terms may mean different things to different people. More anatomically specific terms like “supraomohyoid” and “suprahyoid” remain in usage, but these are also open to abuse and are sometimes used interchangeably [8]. All of these terms do not need to be redefined; instead, they should be replaced with a simple descriptive system that avoids ambiguity and allows clear definition of
Volume 153, March 1987
which node groups are dissected and which structures are preserved. The system of nomenclature for the major lymph node groups used at Memorial Hospital, New York for many years is a sound basis for such a descriptive system [9]. The node groups are depicted in Figure 1. Level I contains nodes of the submandibular and submental triangles. Levels II, III, and IV contain nodes of the upper, middle, and lower jugular chain that lie deep to the sternocleidomastoid muscle which is divided into thirds. Level II also contains the jugulodigastric node and the upper spinal accessory or upper posterior cervical nodes. The point at which the omohyoid muscle crosses deep to the sternocleidomastoid muscle is a landmark that could be used to separate levels III and IV. The juguloomohyoid nodes, therefore, lie at the lower end of level III. Level IV contains mainly lower jugular nodes, but supraclavicular nodes are also present in this region deep to the sternocleidomastoid muscle and medial to the brachial plexus. Level V refers to the contents of the posterior triangle which include mid and lower spinal accessory nodes and transverse cervical nodes. The Memorial Hospital system of nomenclature includes a level VI, comprising nodes around the thyroid gland, and a level VII, comprising nodes of the tracheoesophageal groove and superior mediastinum. There are practical advantages to considering lymph node groups according to the regions in
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TABLE I
Classification of Varlous Modified Neck Dissections According to the Levels Dissected and Structures Preserved Reference
Type of Neck Dissection
1
Bocca & Pignataro [2]
Conservation
Bocca et al [ 41 Jesse et al [ 3]
Functional Functional
Byers [5]
Suprahyoid Supraomohyoid Anterior or modified Posterior Lower Functional Modified (conservative or functional) Regional (selective or partial)
Suen & Wetmore
161
Brown & McDowell [ 81 Calearo 8. Teatini [ 71
Supraomohyoid Functional
Structures Preserved
Levels Dissected
II-V (&I) I-III II-IV I-V
II
11-111 II-IV II B v IV a v I-V II-V (fl)
Variable, for example I & II, bilateral VII I-III II-V
SCM, IJV, SAN, CP, omohyoid tail of parotid, submaxillary gland SCM, SAN, 8, IJV SCM, SAN, & IJV SAN unless invaded Not specified but principally SCM, SAN, & IJV
SCM, IJV, SAN & CP, 8 omohyoid Not specified
SCM, IJV, SAN SCM, IJV, SAN
CP = cervical plexus; IJV = internal jugular vein; SAN = spinal accessory nerve; SCM = sternocleidomastoid
which they are found. Although anatomists give names to certain groups of nodes (for example, jugulodigastric, juguloomohyoid, and spinal accessory nodes), these nodes are removed by dissection of anatomic zones and are not readily identifiable as discrete structures, especially when a large metastatic mass is present. This is especially true of level II, which contains several named lymph nodes or node groups and is the region most frequently involved by oral and oropharyngeal cancers. Using this system of nomenclature, Bocca’s operation is a modified neck dissection encompassing levels II through V and preserving the sternocleidomastoid muscle, internal jugular vein, spinal accessory nerve, cervical plexus, and tail of the parotid gland. Sometimes level I is also included, in which case the submandibular salivary gland is spared. Similarly, the operations of Suen and Wetmore [6], Calearo and Teatini [ 71, and those used at the M.D. Anderson Hospital [3,5] could be concisely described according to the node levels dissected and which structures are preserved. Table I summarizes some of these procedures giving the name of the operation used by each author and the translation into the suggested system. We do not suggest that the term “radical neck dissection” be replaced if it specifically refers to the classic procedure described by Crile [IO] and subsequently advanced by Martin et al [11] and Beahrs [12]. Radical neck dissection in which only the spinal accessory nerve is preserved [13] is quite unambiguous but, for consistency, could be designated a modified dissection of levels I through V sparing the spinal accessory nerve.
312
muscle.
Technique Modified radical neck dissections have been carried out at the University of Alabama Hospitals since 1979. The technique described was developed by the senior author (WAM) and encompasses levels I through IV sparing the sternocleidomastoid muscle, the spinal accessory nerve, and the cervical plexus. The submental triangle is not dissected unless indicated. The internal jugular vein is usually removed in this technique unless a bilateral procedure is carried out, in which case the vein on the side opposite the tumor is spared. Level V is not dissected. The ,posterior limit of the dissection is approximately the posterior border of the sternocleidomastoid muscle. Dissection of the contents of the posterior triangle is not included in this procedure, since lymph nodes in this region are rarely involved by metastatic disease arising from a primary site in the oral cavity, oropharynx, larynx, or hypopharynx (5,141. Furthermore, metastases to the posterior triangle in the absence of involvement of the jugular chain nodes are uncommon [15]. However, if the posterior triangle is to be dissected, we believe the cervical plexus should be sacrificed to facilitate better clearance of this region. The technique is illustrated in Figures 2 through 7.
Comments
Our clinical experience with the modified radical neck dissection described is reported elsewhere [26]. On the basis of this experience and that of other investigators, we believe this operation is appropriate as an elective procedure among patients with epidermoid carcinoma of the upper aerodigestive tract under the following circumstances: (1) When
The American Journal of Surgery
Modified Radical Neck Dissection
Ftgure 2. Inset: The incision preferred by the senior author is shown by the solid line. A useful alternattve is shown by the broken line. Main figure: The flaps have been elevated deep to the p/atysma, preserving the great aurlcular and marginal mandibular nerves. The broken line shows the line along which the fascia investing the sternocleidomastotd muscle will be incised.
Figure 3. The fascia investing the sternocleidomastoid muscle has been incised and elevated from this muscle by sharp dissection. The greater auricular nerve is mobilized, retracted posteriorly, and preserved. The la// of the parotid gland is also preserved but should be removed if the primary tumor involves the skin of the face or lip.
Volume 153, March 1997
Figure 4. The investing layer of fascia has been dissected from the lateral, anterior, and deep aspects of the sternocleldo mastoid muscle. Posteriorly, this dissection is tlmtted by the branches of the cervical plexus crossing from the floor of the posterior triangle to the posterior border of the retracted sternocletdomastold muscle. The anterior be//y of the omohyold muscle is identified and divided, a/towing the posterior belly to retract deep to the sternocleldomastoid muscle. The sptnal accessory nerve, with its branch to the sternocteldomastold muscle, is located on the deep surface of the upper end of the sternocleidomastoid muscle.
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Figure 5. The main dissection is commenced at the lower end of the retracted sternocieidomastoid muscle and carried superiorly with scalpel or scissors. The lower end of the internal jugular vein is doubly ligated, and the usual care to Identify the thoracic duct is taken. This part of the procedure differs from standard radical neck dissection only in that the cervical plexus is preserved. The internal jugular vein may be preserved on one side in synchronous bilateral procedures.
Figure 6. As the dissection is carried superiorly, the attachment of the omohyoid muscle to the hyoid bone is divided, and the carotid bifurcation and hypogiosseal nerve are identified. The posterior belly of the d/gastric muscle is defined and retracted superiorly, whereas the upper end of the sternocleidomastold muscle, along with the spinal accessory nerve and the greater auricular nerve, is retracted posterloriy. This allows clean dissection of level II commencing posteriorly and moving anteriorly. The proximal end of the internal jugular vein is identified, ligated, and divided as close to the jugular foramen as possible.
local disease is advanced and there is a high probability of clinically uninvolved nodes containing occult metastatic disease-that is, in patients with TS or T4 cancers of the oral cavity, oropharynx, supraglottic larynx, and hypopharynx. (2) When resection of the primary tumor is carried out through a neck incision and the possibility of nodal metastases is high. This includes patients with earlyoropharyn-
314
geal, supraglottic laryngeal, and hypopharyngeal tumors but not patients with glottic primary tumors, since they rarely metastasize to the neck unless advanced. If postoperative radiotherapy is planned for the primary site and the neck is clinically uninvolved and does not need to be entered to carry out the resection, for example, in the case of a large oral
The American Journal of Surgery
Modified Radical Neck Dissection
I
Cemtkl A.
Figure 7. The dlssectlon continues in an anterior dtrectlon, removing the contents of the submandibular triangle, including the sallvary gland. By maintaining a plane supertlcial to the superior thyroid artery, damage to the superior laryngeal nerve Is avoided. The neck structures at the completion of dissection are seen.
primary tumor, it may be equally appropriate to electively irradiate the neck along with the primary site rather than perform a modified neck dissection. Because there is a high likelihood of recurrence in the neck when patients with clinically papable nodes are treated by this operation [16], we believe it should be a therapeutic procedure only when there is minimal nodal disease, that is, N1 according to the guidelines of the American Joint Committee on Cancer, 1983 (see Table II), or when the disease is staged NZ by virtue of bilaterality (N& or contralaterality (Ns,.). We believe these patients can be treated according to the assessment of each side of the neck. Patients with bilateral or contralateral N1 disease could therefore have the modified radical neck dissection just described. If more extensive disease is encountered during the procedure a radical neck dissection should be performed, although the spinal accessory nerve could still be preserved in some cases. It is our practice to treat patients with histologically involved lymph nodes with postoperative radiotherapy if there is more than one involved node or evidence of extracapsular spread of metastatic disease. We do not believe that the procedure is appropriate for patients with multiple clinically palpable nodes (Nsb), for those with a clinically palpable node larger than 3 cm in diameter (Nza or N&, for patients with clinical involvement of the posterior triangle, or for patients in whom radiotherapy to the neck has failed. Summary
The terminology relating to the various modifications of radical neck dissection is loose and confusing. A simple system of nomenclature has been sug-
Volume 153, March 1997
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TABLE II
Stage Nx No NI N2
NPZI Nzb N3 N3a
N3b
N3c
Cllnlcal Staging System for Cervical Nodes (American Joint Committee on Cancer, 1983) Description
Minimum requirements to assess the regional nodes cannot be met. No clinically involved node. Single clinically involved homolateral node 3 cm or less in diameter. Single clinically involved homolateral node more than 3 cm but not more than 6 cm in diameter, or multiple clinically involved homolateral nodes, none more than 6 cm in diameter. Single clinically positive homolateral node more than 3 cm but not more than 6 cm in diameter. Multiple clinically involved homolateral nodes, none more than 6 cm in diameter. Massive homolateral node(s), bilateral nodes, or contralateral node(s). Clinically involved homolateral node(s), one more than 6 cm in diameter. Bilateral clinically involved nodes (in this situation, each side of the neck should be staged separately; that is, NSb; right, NPa; left, NT). Contralateral clinically involved node(s) only.
gested which allows specification of the node levels dissected and the structures preserved. A technique of modified neck dissection, which excludes dissection of the posterior triangle and spares the sternocleidomastoid muscle and spinal accessory nerve, has been described. We believe this operation is appropriate when local disease is advanced and clinically uninvolved neck nodes are likely to harbor occult metastatic disease, when resection of the primary tumor is through the neck, or when clinical disease in the neck is minimal. Patients with multi-
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ple palpable nodes, patients with nodes larger than 3 cm in diameter, patients with disease in the posterior trialigle, and patients in whom radiotherapy to the neck has failed may be better served by radical neck dissection. Acknowledgment: We gratefully acknowledge the outstanding work of Samuel K. Collins, MS, AMI, medical illustrator, Birmingham, trations.
Veterans Alabama,
Administration Medical Center, for preparing the operative illus-
7.
8.
9.
10.
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