Chilita, I hope this helps:
IV. CLASSIFICATION OF NECK DISSECTION
A. Comprehensive neck dissections - includes the radical neck dissection
and three modifications, but always refers to a procedure in which all of
groups I - V are removed
1. Radical neck dissection
a. Involves the removal of all lymphatics from the inferior border of the
mandible to the clavicle between the lateral border of the strap muscles
and the anterior border of the trapezius
b. The deep margin of resection is the fascial carpet of the scalene
muscles and the levator scapulae
c. The SCM, the internal jugular vein, and the spinal accessory nerve are
removed with the specimen
d. Traditionally, the only surgical method of treating the neck
i. But with the development of the more limited, less morbid modifications
this is no longer indicated in the N0 neck
ii. Many surgeons no longer advocate this approach in N+ necks unless the
metastatic nodes involve the muscle, vein, or nerve
2. Modified Radical Neck Dissection
a. Based on the work of Suarez as well as that of Bocca and Pignataro
i. Indicate that an en bloc removal of the cervical lymphatics can be
accomplished by stripping the fascia from the SCM and internal jugular
vein
ii. No lymphatic communication was ever noted between these structures and
the cervical lymphatics
iii. These studies point out that both the spinal accessory and the
hypoglossal nerve do not follow the aponeurotic compartments, but rather
run across them; however, their conclusion was that if the tumor did not
directly involve the nerves, they could be spared
b. From the above information and a desire to minimize the shoulder
dysfunction associated with spinal accessory nerve sacrifice came the
development of the modified radical neck dissection
3. Type I Modified Radical Neck Dissection
a. Accomplishes the removal of the same regions of lymphatics as in the
radical neck dissection, but the spinal accessory nerve is spared
b. Used less commonly in the N0 neck, but would be a reasonable choice
with neck disease that involved the SCM or jugular vein without involving
the spinal accessory nerve
c. In a recent study by Anderson, radical neck dissection was compared to
Type I modified radical neck dissection
i. neither survival nor tumor control in the neck was affected by
preservation of the spinal accessory nerve
ii. the pattern of failure was the same for the two different procedures;
the nerve preservation did not predispose to recurrence in that area
4. Type II Modified Radical Neck dissection
a. Involves the same dissection as in the radical neck, but the spinal
accessory nerve and internal jugular vein are spared
b. Similarly indicated in N+ necks with metastatic involvement of the SCM,
but without involvement of the nerve and vein
5. Type III Modified Radical Neck dissection - aka "functional neck
dissection"
a. Similar dissection to the radical neck with preservation of all three
structures
b. The indications for this procedure are controversial
i. In Europe, this operation is popular in the treatment of
hypopharyngeal and laryngeal tumors with N0 necks
ii. Molinari, Lingeman, and Gavilan propose this procedure for N1 necks
when the involved nodes are mobile and no greater than 2.5 to 3cm
ii. Bocca proposes this operation for any neck that has indications for a
radical neck dissection as long as the nodes are not fixed
c. The results from Byer's study demonstrate recurrence rates similar to
those associated with radical neck dissection
B. Selective Neck Dissections
1. This type of dissection arose from the work of Shah, Lindberg, and
Byers which identified the pathways of lymphatic spread in the head and
neck
a. Only those regions with high risk for metastasis are removed
b. A subject of great controversy, some surgeons feel that in necks with
limited disease, these procedures provide the same therapeutic value
i. Recent work by Byers indicates that patients undergoing selective neck
dissection with N1 disease and a mobile node less than 3cm in the first
echelon of lymphatic drainage have similar recurrence rates to those
having a radical neck dissection
ii. Another recent investigation by Kowalski recommends selective neck
dissection for oral cavity cancers with positive nodes at level 1
c. This type of dissection provides the same staging information that
radical neck dissection does, so that prognosis and the necessity of
radiation therapy can be assessed
d. Manipulation of the spinal accessory nerve is minimized in selective
neck dissections
i. Although there is short-term shoulder morbidity with selective neck
dissection, Sobol's prospective study indicates that by 16 weeks,
patients performed significantly better than those who had radical neck
dissection
ii. This same study compared supraomohyoid neck dissection to modified
radical and found that the limited dissection allowed a quicker return to
normal function, but at one year the difference became less
2. Types of selective neck dissection
a. Supraomohyoid (anterolateral) neck dissection
i. Levels I, II, and III are removed sparing the SCM, IJ, and CNIX
ii. Indicated in the treatment of oral cavity lesions
b. Lateral neck dissection
i. Levels II. III, and IV are removed sparing the SCM, IJ, and CNIX
ii. Indicated in tumors of the larynx, oropharynx, and hypopharynx when
the neck is N0, although some advocate this approach with the N1 neck
with nodes limited to level II
c. Posterolateral neck dissection
i. Levels II, III, IV, and V are removed sparing the SCM, IJ, and CNIX
ii. Useful in the treatment of skin tumors with metastatic potential
located in the posterior scalp or neck such as melanomas, squamous cell
carcinomas, and Merkel cell carcinomas
C. Extended neck dissections - describes any of the above dissections that
include the removal of additional structures or other groups of lymph
nodes
1. Retropharyngeal node involvement often occurs in tumors of the
pharyngeal walls, and would warrant an extended neck dissection
2. Thyroid, subglottic, tracheal and cervical esophageal carcinomas
require the extension of the neck dissection to include level VI
3. Tumor extension involving the carotid artery, the hypoglossal nerve,
the levator scapulae muscle may necessitate excision of these additional
structures
More here:
http://www.emedicine.com/ent/topic501.htm and even more here:
http://www.emedicine.com/ent/topic748.htm#target1 WARNING: there are pictures at the above site! they are graphic.
