Morbidity and mortality from thyroidectomy occur rarely; however, possible serious postoperative complications could cause a devastating life-long handicap. Currently, the main postoperative complications of thyroidectomy are hypoparathyroidism and recurrent laryngeal nerve injury. The extent of resection, reoperation for completion, patient volume per surgeon and the surgeon’s inexperience are risk factors for morbidity of thyroid surgery. Meticulous dissection is a key factor in minimizing the development of complications
Postoperative hypoparathyroidism is a major concern may lead to prolonged hospitalization and increased cost. In several studies, the incidence of transient hypoparathyroidism varied from 6.9% to 46% while a rate of 0.4% to 3.3% has been reported for permanent hypoparathyroidism. Falk et al. reported that transient hypoparathyroidism occurred in 27.8% of their cases manifested mostly as transient hypocalcemia, easily managed with oral supplementation of vitamin D and Ca3
In the literature, all research related to thyroid surgery and staining of parathyroid glands was performed through intravenous and/or intra-arterial methylene blue injections. Dudley et al. used an intravenous infusion technique on 17 patients. In all cases, one or more of the parathyroids have been demonstrated with histological confirmation. Elias et al. used the same technique on 59 consecutive patients undergoing thyroid gland surgery (including 23 with carcinoma). Precise localization of the glands was possible in 87%. The intravascular (intravenous and/or intra-arterial) techniques described above ensure only parathyroid gland visualization and, accordingly, contributes to the prevention of hypoparathyroidism
The other major complication in thyroid surgery
] is recurrent laryngeal nerve palsy. This results in significant impairment of the quality of life
] and negatively impacts on job performance
]. Erbil et al. reported that recurrent laryngeal nerve palsy occurred in 1.8% of their cases
To help identify the RLN and measure its function immediately before thyroid resection, various medical devices have been developed over the past two decades for intraoperative use. Several methods have been described for RLN monitoring including finger palpation of the cricoarytenoid muscle during nerve stimulation, vocal cord observation by direct or fiberotic laryngoscopy and the use of intramuscular vocal cord electrodes
In a recent multicenter trial of 16,448 thyroidectomies, Dralle H. et al. concluded that visual nerve identification, in respect to RLN treatment, emerged as the “gold standard” of care
Methylene blue is a hetero-cyclic aromatic chemical compound
] which in recent years has been widely used in sentinel lymph node biopsies
]. For prevention of hypoparathyroidism, staining of the parathyroid glands is not a new technique but was first described by Klopper et al. in 1966
]. Dyes first used by authors were toluidine blue and trypan blue
], a derivative isomer of toluidine. After their potential teratogenic effects were discovered, they began to be replaced by methylene blue
Studies in the literature show no significant differences between complication rates in their study cohorts and in patients undergoing total or subtotal thyroidectomy without the methylene blue spraying technique. Our research, on the other hand, shows major differences.
We did not use an expensive device for identifying the important structures. The dye is inexpensive, it can be easily and safely applied, unless by an inexperienced surgeon. We sprayed the dye onto the perithyroidal area, which is not normally used via the intravascular approach. Also, we aimed to identify not only parathyroid glands but also recurrent laryngeal nerve and inferior thyroid artery.
We observed that the wash-out time of parathyroid glands was less than three minutes but for thyroid glands was more than 15 minutes. We hypothesize that, the differences in time are due to the lympho-vascular pattern of the tissues. Histologically, the lympho-vascular structure of parathyroid glands is extremely dense. This peculiarity of the tissue is vital for immediate wash out of methylene blue staining. Unstaining of the recurrent laryngeal nerve during the procedure is not surprising because, like other peripheral nerves, it is covered by a schwann sheath and also has an avascular structure. Arterial non staining is due to its thick wall structure as well as reverse blood flow (not from tissue to heart but from heart to tissue) and. Because veins transport methylene dye from tissues, they immediately turn into blue in color.
Conventionally, surgeons identify the RLN by using judging its relationships with the inferior thyroid artery, tracheoesophageal groove, and ligament of Berry as anatomical landmarks. However, because of the numerous variations of this neurovascular relationship altered also by pathologic conditions of the gland, identification of the artery does not assure accurate identification and preservation of the recurrent laryngeal nerve. After spraying the dye onto the perithyroidal area, however, a surgeon can easily identify the recurrent laryngeal nerve, parathyroid glands and inferior thyroid artery. Once found, the nerve with all the identified branches can be quickly and safely followed through its entire course until it enters the larynx. When all the parathyroid glands have been identified, special care then can be easily taken to preserve their vascular pedicles.
Intraoperative stres can be increased by various intraoperative stressors, e.g., rising intolerance of physician error, potential legal issues, and medical insurers can increase. Kern et al. pointed out that surgical injuries accounted for the greatest number of lawsuits and the highest cost of litigation