Patients then underwent selective parathyroidectomy using a minimally invasive approach. The average incision for minimally invasive surgery is about 4 cm, compared with an 8 cm average in the standard open approach. More important, far less deep dissection is required to find and excise the abnormal gland.
Explore This IssueFebruary 2007
To ensure that the diseased gland was successfully excised, levels of parathyroid hormone (PTH) were assayed preoperatively and intraoperatively. With this measure, elevated PTH levels reflective of hyperparathyroidism would be expected to fall precipitously once the diseased gland is removed; if PTH levels remain high following excision of one abnormally enlarged gland, it suggests that another gland is affected (see graph), or more likely the patient has parathyroid hyperplasia. In this study, postoperative serum calcium levels with a mean follow-up of 11 months and minimum of 6 months were normalized in more than 97% of the patients, confirming the efficacy of the approach. Indeed, 100% of the patients who were managed with single-gland excision with unilateral directed exploration became normocalcemic and remained so.
Dr. Sadeghi reported that 90% of the patients who were diagnosed with single-gland adenoma required only minimally invasive, single-gland exploration. Ten percent of patients having eventually confirmed diagnosis of single-gland disease needed bilateral exploration for nonlocalizing adenoma or false negative imaging.
Minimally invasive parathyroidectomy has made a big difference, said Dr. Sadeghi. It has been shown by numerous studies, including our own, that it has a 97% or more success rate and that we are not compromising success rates as compared to traditional surgery. He said that recurrence rates for both approaches hover around 2 to 3%.
The overall risk of minimally invasive parathyroidectomy is below 1%, compared with 2% or less for standard surgery, said Dr. Sadeghi. Smaller incisions with less dissection mean that patients recover faster, return to work faster, and have better cosmetic outcome. The surgery is performed on an outpatient basis. It reduces the risk of postoperative hypocalcemia, except in few cases of very large adenomas where the other three normal glands are functionally suppressed and the patient may suffer transient hypocalcemia. Calcium supplementation similar to a post-thyroidectomy strategy eliminates this risk. This approach leads to fewer major complications, such as bleeding and hematoma formation.
Minimally invasive surgery also reduces the risk of residual injury to the recurrent laryngeal nerve-a danger of any thyroid or parathyroid surgery. None of the patients in this study suffered any of these complications. Because there is less disturbance of the remainder of the neck and the thyroid bed, and the contralateral side is not dissected at all, it also allows for easier and safer re-exploration in the few cases with persistent or recurrent disease.