Minimal access surgery — thyroid and parathyroid

Abstract

The concept of surgical invasiveness cannot be limited to the length or to the site of the skin incision. It must be extended to all structures dissected during the procedure. Therefore, MIT or MIP should properly be defined as operations through a short and discrete incision that permits direct access to the thyroid or parathyroid gland, resulting in a focused dissection.Parathyroid glands are particularly suitable for minimally invasive surgery as most parathyroid tumors are small and benign. MIP are performed through a limited or discrete incision when compared to classic open transverse cervical incision and are targeted on one specific parathyroid gland. The concept of these limited explorations is based on the fact that 85% of patients will have single-gland disease. MIP must be proposed only for patients with sporadic hyperparathyroidism in whom a single adenoma has been clearly localized by preoperative imaging studies.The minimal access approaches to the thyroid gland may be broadly classified into three groups: the mini-open lateral approach via a small incision, minimally invasive video-assisted thyroidectomy via the midline and various endoscopic techniques. Endoscopic extracervical approaches have the main advantage of leaving no scar in the neck but cannot reasonably be described as minimally invasive as they require more dissection than conventional open surgery.Initially the indications for MIT were a solitary thyroid nodule of less than 3 cm in diameter in an otherwise normal gland. Today, MIT are also proposed in patients with small nodular goiters, Graves's diseases and low risk papillary thyroid cancers. Some concern remains about the radicality of MIT in this latter group but preliminary results are comparable to those of conventional surgery both in terms of I-131 uptake and serum thyroglobuline levels.Demonstrating the advantages of MIT and MIP over conventional surgery is not easy. Main complications, such as nerve injury, hypoparathyroidism, or hemorrhage, are the same as in conventional surgery. Several studies comparing conventional surgery with minimally invasive techniques using a cervical access have shown a diminution of postoperative pain, and better cosmetic results with minimally invasive techniques. MIP and MIT seem overall to be an advance but only randomized studies will demonstrate the real benefit.