Abstract
OBJECTIVE Functional neck dissection was first described by Bocca and Pignataro in 1967. It has been used in clinical practice for years, but remains controversial among neck-surgery experts. This study was designed to evaluate indications and curative effects of functional-neck dissection (FND).
METHODS One hundred and fifty–two cases which underwent FND were reviewed with an analysis of pathological specimens and follow-up datas.
RESULTS The series of FND included 20 cases of tongue carcinoma, 23 cases of larynx carcinoma, 96 cases of thyroid papillary adenocarcinoma, 9 cases of follicular adenocarcinoma and 4 cases of medullary adenocarcinoma; the five-year recurrence rate for tongue carcinoma was 12.5%, 14.3%, 40.0% and for a larynx carcinoma was 20.0%, 16.7%, 50.0% in N0 stage, N1, stage, N2a stage, respectively. The 5-year recurrence rate of thyroid papillary adenocarcinoma was 6.5%, 7.1% in N1a, N1b, respectively.
CONCLUSION Functional neck dissection is indicated in early and low malignant head and neck neoplasms and results in satisfactory curative effects.
keywords
Functional neck dissection (FND) has been used widely in head and neck surgery since proposed in 1967 by Bocca and Pignataro [1]. There is still controversy regarding the indications and clinical effects of modified neck dissection(MND) in this country and abroad [2,3]. As a result, the usage of this procedure is limited in some degree. One hundred and fifth-two MNDs had been performed in this center from August 1983 to August 1996, and were reviewed and analyzed to investigate the indication and clinical effects of modified neck dissection.
MATERIALS AND METHODS
Clinical Population
The 135 patients reviewed were 51 men and 84 women. Ages ranged from 12 to 62 with a median age of 37. Primary cancer locations were as follows: 20 patients with tongue squamous cell carcinoma(TSCC), 23 patients with laryngeal squamous cell carcinoma (LSCC), 82 patients with thyroid papillary carcinoma (TPC), 7 patients of thyroid follicular carcinoma (TFC), and 3 patients with thyroid medullary carcinoma(TMC). Modified-neck dissections were performed 152 times. There were 17 patients who underwent bilateral modified neck dissection including 14 patients with thyroid papillary carcinoma, 2 patients with thyroid follicular carcinoma and 1 patient with thyroid mendullary carcinoma. Combined modified–neck dissections(Combined Type) in 93 patients were performed with radical resection of the primary site. Fifty–nine patients received a singular modified neck dissection (Singular Type). The distribution of the patients is shown in Table 1. According to UICC TNM 1997, there were 3 cases of T, TSCC, 12 cases of T2 TSCC, 5 cases of T3 TSCC; 8 patients with N0, 7 patients with N1, and 5 patients with N2a. Three patients presented with a tumor at the anterior 1/3 of lateral side of the tongue, 12 patients presented with a tumor at the middle 1/3, 2 patients presented with a tumor at the posterior 1/3 of the tongue, 3 patients presented with a tumor at the belly of the tongue. For LSCC, there were 6 cases of T2, 15 cases of T3, 2 cases of T4; 5 patients with N0, 12 patients with N1, 6 patients with N2a. There were 12 patients with glottic cancer, and 11 patients with supraglottic cancer. For TPC, there were 6 cases of Nx, 62 patients with Nla, 28 patients with Nlb (Nx suggests that the patients received irregular treatment for the neck including lumpectomy and biopsy). For TFC, there were 5 patients with N1a, 4 patients with N1b. For TMC, there were 3 patients with Nla and 1 patient with N1b.
Distribution of every kind functional neck dissection (cases)
Modified neck dissection was performed under general anesthesia. If general anesthesia wascontraindicated, local anesthesia strengthened by basic anesthesia was used.
Surgical procedure: (1) The incision of modified–neck dissection was as reported by Li, et al [4]. A skin flap was developed first. The great auricular nerve and external jurgular vein were preserved during the process. (2) The accessory nerve was detected and preserved before the anterior border of the trapezius muscle. The Level V lymph nodes were dissected. The onohyoid muscle and transverse cervical artery were preserved. The dissection of Level V lymph nodes were conducted to the posterior border of the sternocleidomastoid muscle (SCM) (Fig. 1). (3) The anterior and posterior borders of the SCM were dissected and dragged outward to expose the internal jugular vein. The Level IV and III lymph nodes were dissected and reflected from the surface of the carotid artery (Fig.2). (4) In the dissection of lymph nodes in the carotid artery triangle, the SCM muscle should be dissected adequately to expose this area. Following the exposed part of the accessory nerve in the posterior cervical triangle, the accessory nerve was freed to the deep part of the superior SCM muscle. The tissue block including Level V, IV, and III was dragged and reflected inward and upward to dissect the posterior group of lymph nodes. After the tissue block was reflected and crossed over the internal jugular vein, the anterior group of lymph node was dissected (Fig.3). The tissue sample was resected totally en–bloc.
Lymph nodes in V level of neck dissection
A: External jugular vein B: Great auricle nerve C: Accessory nerve D: Sternocleidomastoid muscle E: Internal jugular vein F: Dissected lymph nodes and fatty tissue
Lymph nodes in III, IV level of neck dissection
G: Common carotid artery H: Vagus nerve
Lymph nodes in II level of neck dissection
I: Phrenic nerve J: Post belly digastric muscle K: Lower polar of parotid gland
RESULTS
All of the patients were followed-up for 5 years after surgery. The neck recurrence rates in TSCC and LSCC after modified neck dissection are shown in Table 2. There were 6 patients with clinical N0 neck before MND and found to be pathologically positive (pN,) after surgery, including 3 patients with TSCC and 3 patients with LSCC. The occult cervical lymph node metastasis was 46.2%. Ten patients with neck recurrences received neck node biopsy which were confirmed pathologically. There were 6 patients who presented with a neck node recurrence in Level IIb (60%). Two patients presented with a neck recurrence in Level III and another two in Level IV. Ten patients with neck recurrence could not be salvaged radically because the recurrent nodes were hard, without a clear margin and fixed to the surrounding tissue, especially the carotid artery. The 5-year survival rate is listed in Table 3.
Five–year recurrence rate of tongue and larynx carcinoma affer FND(percent)
Five-year survival rate of tongue and larynx carcinoma affer FND(percent)
The neck node recurrence over 5 years after surgery for thyroid cancer is shown in Table 4. There were 9 patients with a neck–node recurrence: 6 presented in Level IIb(66.7%), 2 presented in Level IV and the paratracheal area, 1 patient presented in Level IV. All of the recurrent nodes had a clear margin, hard and movable. Of these, 8 received regional total resection, preserving in all the internal jurgular vein, SCM and accessary nerve. Another patient with thyroid medullary cancer presented with a neck recurrence and was not salvaged by surgery because of double-lung metastasis. The 5–year survival rate in thyroid cancer was 100%. The 5-year recurrence rate and 5–year survival rate after all kinds of surgery in Table 2, 3 and 4 showed no significant differences analyzed by Chi-square test (P>0.05), probably due to a too small population in these groups.
Five-year recurrence rate of thyroid carcinoma affer FND(percent)
DISCUSSION
The advantages of MND
In 1967 Bocca and Pignataro proposed MND according to the anatomical characteristics of neck and surgical oncologic principles. Based on the classical radical neck dissection, it is necessary to preserve the internal jurgular vein, SCM muscle, and accessory nerve in MND. It is called Functional Neck Dissection or Modified Neck Dissection. This procedure evaded the disadvantages of severe cervical disformation and functional failure in classical radical neck dissection. Moreover, in patients with both lateral neck lymphadenopathy MND can be performed on both sides, especially in young female patients [3]. In this group of 152 MND cases, there were only 5 patients presenting with fibrotic formation of the SCM muscle after MND, two patients manifested ipsilateral lop–shoulder and another 2 patients showed facial edema and headache, etc.
Clinical curative effect of MND
Suarez et al in 1963 confirmed in an anatomical study that cervical lymph nodes were located in the cervical fascia space. There were no lymph nodes crossing muscles, nerves or the external vascular membrane. Further studies insisted on the theory that the muscles, nerves and blood vessels which surrounded by deep cervical fasicia separated from the lymph nodes in neck[5]. All of these anatomical characteristics were the basic theory for MND treatment. Bocca et al (1984) published a report in which 843 patients with head and neck cancers were treated by MND [6]. The neck recurrence rate was not influenced by different surgical procedures as compared with radical-neck dissection in a similar period. They suggested that if lymph nodes did not invade the capsular membrane and did not spread to other tissues outside of the capsule, the lymph nodes could be dissected from the fascia space and resected en–bloc and totally. MND and RND can produce the same clinical curative effect. In this group, the 5–year survival rates of patients with TSCC, LSCC and TC were 80.0%, 78.3% and 100% respectively. Compared with Li Zheng-quan [7] who reported 53.8%, 41.7% and 89.4% 5-year survival rate after RND, there was a statistical difference analyzed by Chi-square test(P<0.05). The 5-year neck recurrence rate in our group (23.8%) was lower than the 37% as reported by Li Zheng-quan in similar patients. Moreover, the 5–year neck recurrence rate in TPC(7.3%) was also lower than the 14.2% reported by Zeng Zong–yuan in patients treated by RND [8] with a statistically significant difference (P <0.05). Although it is difficult to draw the conclusion that MND has a better clinical curative effect than RND, all of these data strongly support the view proposed by Bocca et al[6].
Clinical indications for MND
There is still a dispute regarding the indications for MND. In our study it was demonstrated that: (1)Neck metastatic lymphadenopathy in patients with TSCC and LSCC has a strong tendency to invade other tissues. Moreover, it resists radiotherapy and chemotherapy. As a result, MND should be carefully considered. According to our experience, the indications for MND should be as follows: ①A primary lesion has been radically removed or can he radically resected in combined radical surgery. ②Clinical N0 patients. ③Clinical N1 patients. ④No distant metastasis. The contraindications for MND include clinical N2a patients and/or if the diameter of the lymph nodes is more than 3cm and/or if the lymph nodes are fixed. This is the case because there is capsule infiltration or (fixation to other tissue) out of capsule when the diameter of the lymph nodes is more than 3cm or the lymph node is fixed[9]. The 5-year recurrence rate in N0, N1 patients with TSCC and LSCC in our group was lower than in N2a patients. However, the 5-year survival was higher than in N2a patients. (2) In TPC and TFC, because of high cell differentiation and lower invasion ability, cancer cells will be limited inside the capsule of lymph nodes for a long time. Therefore, it is suggested that the indications for MND should be: ①Clinical N1a patients. ②Clinical N1b patients. ③ Lymph nodes with a clear margin that are movable and by CT scan separatable from the internal jurgular vein, SCM muscle and carotid artery. Clinical experience shows that recurrent neck nodes after surgery can be salvaged by selective neck dissection and it can still gain a radical-treatment effect[10].
Surgical technique influences the clinical effect of MND
It is suggested that sharp dissection should be done to preserve the integrity of the cervical fascia during the process of MND. The complete removal of the surgical sample block should be insisted upon, and avoid entering the fascia space where there are lymph nodes. There are five points to which more attention should be paid: (1)The carotid sheath membrane should be peeled off. This sheath surrounds the carotid artery, internal jugular vein and vagus nerve. Jugular lymph tissue attaches to the surface of this carotid sheath and it should be removed totally during neck dissection. (2)The posterior group of Level II is located just behind the deep surface of the superior part of the SCM muscle. It is difficult to expose this in neck dissection. It also surrounds the accessory nerve. As a result, it is difficult to dissect this area and there is a tendency to leave some lymph nodes in this area. The result of this study showed that most of the neck–node recurrence was in this area. If thee are numerous swollen nodes or their location is a little bit higher in this area, and if the nodes are near to the inferior pole of the parotid gland making them difficult to expose, the lower part of the SCM muscle just near the clavicle bone can be cut. After the muscle is reflected upward, it is easy to see the lymph nodes directly and dissect them. The SCM muscle may present with fibrosis and it will influence some function of the muscle. (3) The epimysium should be preserved carefully when dissecting the SCM muscle in order to avoid fibrosis of the muscle and protect from functional interference. (4) The external jugular vein and gross facial vein should be preserved otherwise facial edema will result. (5) Dissection of the accessory nerve should not be excessive otherwise it will be surrounded by fibrotic tissue influencing its vascular support and function, finally leading to atrophy of the trapezius muscle resulting in lop–shoulder.
- Received January 18, 2004.
- Accepted March 12, 2004.
- Copyright © 2004 by Tianjin Medical University Cancer Institute & Hospital and Springer
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