1. Incidence of marginal mandibular nerve palsy in neck dissection N Amin, H Dixon, N Gibbins, S Lew-Gor Brighton and Sussex University Hospitals United Kingdom

2. Marginal Mandibular Nerve

3. Our Project Limited data Informed consent important part of pre- assessment Communication errors heart of many complaints

4. Our Project Rate of MMN palsy (temporary/permanent) vs. Type of ND

5. Method Retrospective 2 year review 88 neck dissections (ND) reviewed 4 excluded 84 total – Pre- and post-operative MMN function including whether the MMN was sacrificed intra-operatively. – Time until palsy resolution – Type of neck dissection – The grade of the operating surgeon Statistical analysis

6. AAO-HNS classification of neck dissections Radical neck dissection (RND) – removal of ipsilateral cervical lymph nodes in levels 1-5 as well as the sternocleidomastoid muscle (SCM), internal jugular vein (IJV) and the spinal accessory nerve (SAN). Modified radical neck dissection (MRND) – removal of ipsilateral cervical lymph nodes in levels 1-5 with preservation of one or more of the SCM, IJV and SAN. Selective neck dissection (SND) – there is preservation of one or more groups of lymph nodes as well as the SCM, IJV and SAN. Extended neck dissection (END) – involves a RND with removal of another group of lymph nodes or another non-lymphatic structure.

7. Results 75 patients 84 neck dissections Mean age 66.1 (32 – 89 years) M 4.55:1 F

8. Results 20 RND 20 MRND 28 SND 16 END 8 patients had pre- operative radiotherapy

9. Results 10/84 (11.9%) – MMN palsy 8/84 (9.5%) – permanent 2/84 (2.4%) – temporary

10. Results 57 neck dissections involved level I Total palsy rate was 10/57 (18.5%) 14.0% (8/57) – permanent 3.5% (2/57) – temporary p-value = 0.046

11. Results In RND there was a higher risk of a permanent MMN palsy (20%) compared to MRND (10%), SND (3.6%) or END (6.2%) 10% risk of a temporary MMN palsy in patients undergoing MRND Statistically insignificant 10% 3.6% 20% 6.2%

12. Results Parotid gland – 2 Oral cavity – 5 Larynx – 1

13. Discussion Informed consent is a vital part of pre- operative assessment. Incidence of MMN palsy post level I ND is not widely quoted. Important patients are aware of potential morbidity and potential treatment options.

14. Conclusion If level I dissection is performed, a permanent MMN palsy rate of 14% or 1 in 7 may be quoted to the patient. Adequate resection of disease in level I and the parotid region may require sacrifice of the MMN.

15. References 1.Robbins KT, Clayman G, Levine PA, Medina J, Sessions R, Shaha A, 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;128:751-8. 2.Hazani R, Chowdhry S, Mowlavi A, Wilhelmi BJ. Bony anatomic landmarks to avoid injury to the marginal mandibular nerve. Aesthet Surg J. 2011 Mar;31(3):286-9. 3.Batra AP, Mahajan A, Gupta K. Marginal mandibular branch of the facial nerve: An anatomical study. Indian J Plast Surg. 2010 Jan;43(1):60-4. 4.Dingman RO, Grabb WC. Surgical anatomy of the mandibular ramus of the facial nerve based on the dissection of 100 facial halves. Plast Reconstr Surg 1962; 29:266–272 5.House JW, Brackman DE. Facial nerve grading system. Otolaryngol Head Neck Surg. 1985; 93:146–147 6.Bron LP, O'Brien CJ. Facial nerve function after parotidectomy. Arch Otolaryngol Head Neck Surg. 1997 Oct;123(10):1091-6. 7.Møller MN, Sørensen CH. Risk of marginal mandibular nerve injury in neck dissection. Eur Arch Otorhinolaryngol. 2012 Feb;269(2):601-5. 8.Batstone MD, Scott B, Lowe D, Rogers SN. Marginal mandibular nerve injury during neck dissection and its impact on patient perception of appearance. Head Neck. 2009 May; 31(5):673-8 9.Gosain AK. Surgical anatomy of the facial nerve. Clin Plast Surg. 1995 Apr;22(2):241-51. 10.Baker BC, Conley J. Avoiding facial nerve injuries in rhytidectomy. Anatomical variations and pitfalls. Plast Reconstr Surg 1979; 64:781–795 11.Ducic Y, Young L, McIntyre J. Neck dissection: past and present. Minerva Chir. 2010 Feb;65(1):45-58. 12.Seddon HJ. Three types of nerve injury. Brain 1943; 66(4): 237-288 13.Meier JD, Wenig BL, Manders EC, Nenonene Continuous intraoperative facial nerve monitoring in predicting postoperative injury during parotidectomy, Laryngoscope. 2006 Sep;116(9):1569-72

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