Upsala J Med Sci 81: 93-95, 1976 Preoperative Recurrent Laryngeal Nerve Paralysis in Patients Subjected to Thyroid Surgery KARL ERIK AROSENIUS and SVEN GREVSTEN From the Department of Surgery, Central Hospital, Falun, Sweden ABSTRACT RESULTS (Table I and 11) All cases of preoperative recurrent nerve paralysis have been analysed in an unselected material of patients sub- jected to thyroid surgery at the Surgical Clinic in Falun during the period of 1969-74. The preoperative finding of recurrent nerve paralysis as a malignant sign is discussed. INTRODUCTION Hoarseness is a sign of malignancy, when found during the preoperative clinical examination of patients who present with a goitre (1). This is a classical statement. Hoarseness is due to loss of function in the re- current laryngeal nerve and/or the superior la- ryngeal nerve and is usually caused either by CNS damage or mechanically by section, pressure, or traction somewhere along the course of the nerve. This damage need not always be due to malignancy ( 2 ) . To illustrate this, we have studied the occurrence of pre-operative recurrent laryngeal nerve paralysis in a series of patients subjected to thyroid surgery during the 5-year period, 1969 to 1974. Among 445 patients without carcinoma 5 cases of recurrent laryngeal nerve paralysis-one was partial-were found preoperatively. In 4 of these the paralysis has persisted in one case the nerve function recovered completely. At operation, 3 patients had large adenomas, one patient a nodular goitre and in one patient a bulging carotid artery was found. In 3 cases the nerve was seen to be compressed by an adenoma; in one of these the adenoma was calcified. The pathological diagnosis in 4 cases was nodular colloid goitre. In one case no pathological findings were present. In 2 cases X-ray examination showed extreme tracheal compression. In 3 patients the history of hoarseness began less than 2 weeks before admission; in one of these the nerve function returned later. In another 2 patients hoarseness had been present for longer. The scinti- gram performed on the patient with a bulging carotid artery showed a small impression on the thyroid lobe on the side of the paralysis. Of the 31 patients with thyroid cancer, there were 5 cases of recurrent laryngeal nerve paralysis. MATERIAL AND METHOD This studv is based on the records of patients admitted DISCUSSION for thyroid surgery to the surgical clinic at Falun between The recurrent nerve innervates the intrinsic 1969 and 1974. During this period a total of 476 thyroid muscles of larynx and passes the inferior thyroid operations were performed. Thyroid cancer was present in 31 cases and benign goitre in 445. The vocal cord func- tion of all patients was checked preoperatively. Those patients with recurrent nerve paralysis have been artery in a variable fashion (3). When the nerve is injured, ordinary hoarseness Occurs and the iPsilatera1 vocal cord is Primarily followed up for 1 to 5 years and their vocal cord function immobilized in the paramedian or intermediate has been checked at intervals after the operation. nnsitinn 1 3 . 4. 5) was found, were recorded. muscle. It accompanies the superior thyroid artery Upsala J Med Sci 81 94 K . E . Arosenius and S . Grevsten Table I . Preoperative recurrent laryngeal nerve paralysis in benign goitre Preoperative Tracheal Patient’s Onset of paralysis paralysis (+). PAD from the compres- age, less than 14 days Postoperative operative sion on Operative findings, sex before admission recovery (R) spicement X-ray gross pathology 42 P + sin.+R Hoarseness and acute growth 54 0 79 0 67 0 60 0 - dx+ (partial) Tumor to the right in jugulum. Scintogram: small impression on the right thyroid lobe. + bilat. + dx t - Onset paralysis 30 years earlier at the end of a preg- nancy-“goitre already then” + sin. + Cystic thyroid Not per- tissue+ formed nodular colloid goitre with haemorrhage - Not per- formed Nodular colloid Extensive goitre compres- sion Nodular colloid Not per- Big adenoma on left side Bulging carotic artery on right side in jugulum. Otherwise nothing. Nodular goitre and “thin recurrent nerve” Right-sided thyroid goitre formed adenoma, “Big as a fist”. “The recurrent nerve firmly pressed by the adenoma where it is calcified.” Nodular colloid Extensive The goitre bigger goitre compres- on left side sion “the recurrent nerve pressed flat behind the biggest adenoma”. medially. It is usually covered by the fascia of the inferior constrictors, but in 15% it is found in the thyroid sheath and in another 6% the nerve courses among the branches of the superior thyroid artery (3, 6). The first effect of laryngeal nerve injury is a re- duction in the vocal cord range, particularly in the higher register. The affected cord moves but lies at a lower level than normal (7). The vocal cord is also irregular or wavy in outline (8). This is easy t o foresee clinically. Simple hoarseness due to recur- rent laryngeal nerve damage is the commonest sign and can be explained anatomically. In about 40% (3, 9, 10) (some variation of the figures for different authors) the nerve divides into two or more branches, 5 cm or more below the level of the cricothyroid joint. On entering the larynx the branches may be as much as 6 cm apart (11). Furthermore, in 10% the nerve penetrates the thyroid gland before entering larynx (3, 12). The branches of the recurrent nerve thus form a delta before entering the larynx and this branch Table 11. Preoperative recurrent laryngeal nerve paralysis in patients subjected t o thyroid surgery in the y e a r s 1969-74 at the surgical clinic in Faiun Thyroid cancer Benign goitre Total - - n % n % n 9% N o recurrent nerve paralysis 26 83 440 99 466 98 31 100 445 100 476 100 Recurrent nerve paralysis 5 17 5 1 10 2 Upsala J M e d SciRl Preoperative recurrent laryngeal nerve paralysis 95 delta can b e partly or totally fixed in t h e thyroid tissue. Local swelling of the gland in the region of the delta can exert considerable traction on t h e diverging branches of t h e nerve and produce distor- tion particularly at the branching point, i.e. affect- ing the whole nerve. An unbranched nerve would of course move more easily and adapt itself to the change of form i n the surrounding tissue. General or specific local growth of the thyroid gland can thus damage the recurrent nerve. T h e lesion can b e caused by tense, diffusely growing processes like cancer or Riedel’s goitre but local changes such as local cancer, cystic adenoma, nodular goitre or acute subcapsular haemorrage can also cause similar damage. In our material of patients subjected t o thyroid surgery from 1969 to 1974 (Table 11) (cancer pa- tients included), we have found 10 cases with pre- operative paralysis of the recurrent nerve. 5 of those 10 had no cancer. Although 50% of the cases of paralysis belong to the cancer group, we think it is an exaggeration to describe the preoperative find- ing of recurrent nerve paralysis as a sign of malig- nancy. A statistical reservation must be made con- cerning the figures in this study. The figures are collected from a patient material in a goitre region. The local goitre frequency clearly affects the prob- able cause of preoperative recurrent nerve paraly- sis. Consequently in a region with less goitre a preoperative nerve paralysis may b e more relevant as a malignant sign. It is worth noting therefore that “locality” may influence the clinical significance of the presence of preoperative recurrent laryngeal nerve paralysis. R E F E R E N C E S I . Cole, W. H., Slaughter, D. P. & Majazakis, J. D.: Carcinoma of the thyroid gland. Surg Gynecol Obstet 89: 349, 1949. 2. Widstrorn, A , : Vocal cord palsies following surgery for benign non-toxic goitre. Acta Otolaryngol75: 370, 1975. 3. Kratz, R. C.: The identification and protection of the laryngeal motor nerves during thyroid surgery. A new microsurgical technique. Laryngoscope 83: 59, 1973. 4. Wagner, R.: Die Median Stellung der Stimrnband der bei der Recurrenslahmung. Arch Path01 Anat Physiol 124: 127, 1890. 5 . Dedo, H. H.: The paralyzed larynx: An electromyo- 6 . 7. 8. 9. 10. 11. 12. Mossman, D. A. & De Wesse, M. S . : The external laryngeal nerve as related to thyroidectorny. Surg Gynecol Obstet 127: 101 1, 1968. Nordland, M.: The larynx as related to surgery of the thyroid. Based on an anatomical study. Surg. Gyne- col Obstet 91: 449, 1950. Lawson, L. J . : The superior and recurrent laryngeal nerves. Quart bull Northwestern univ med sch 22: 356, 1948. Lawson, L. J . : Recurrent laryngeal nerve paralysis. A revised concept based on the dissections of 100 cadavers. Ann Otol Rhinol Laryngol61: 567, 1952. Rustad, W. H. Revised anatomy of recurrent laryngeal nerves. Surgical importance based on the dissection of 100 cadavers. J Clin Endocrinol Metab 14: 87, 1954. King, B . T. & Gregg, R . L.: An anatomical reason for the various behaviours of paralyzed vocal cords. Ann Otol Rhinol Laryngeol57: 925, 1948. Berlin, D. D.: The recurrent laryngeal nerves in total ablation of the normal thyroid gland. An ana- tomical and surgical study. Surg Gynecol Obstet 60: 19, 1935. Received January 19, 1976 Address for reprints: Sven Grevsten, M.D. Department of Surgery University Hospital S-750 14 Uppsala Sweden ~. graphic study in dog and humans. Laryngoscope 80: 1455, 1970. Upsala J Med Sci 81