Combination Surgical Approach May Limit Hypoparathyroidism After Thyroid Surgery, Study Says

Joana Carvalho, PhD avatar

by Joana Carvalho, PhD |

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Researchers may have found a way to decrease the risks of temporary or permanent hypoparathyroidism following thyroid surgery. It consists of a surgical technique to preserve blood supply to the parathyroid glands and an injection of small carbon particles that allow surgeons to spot the parathyroid glands easily during surgery.

The method is described in the study, “Reduction in postoperative hypoparathyroidism following carbon nanoparticle suspension injection combined with parathyroid gland vasculature preservation,” published in the Journal of International Medical Research.

Hypoparathyroidism is a rare disorder caused by low levels of the parathyroid hormone (PTH) in the body. Normally, PTH is produced when blood levels of calcium fall and trigger its increase. One of the consequences of low PTH levels is a marked decrease of calcium in the blood.

In many cases, hypoparathyroidism occurs in people who undergo thyroid surgery that causes permanent damage to the neighboring parathyroid glands, the structures responsible for producing PTH. This is called post-surgical hypoparathyroidism.

“Post-operative hypocalcemia [low levels of calcium in the blood] causes patient discomfort, with effects such as perioral [around the mouth] numbness/tingling, seizures, laryngeal spasm, and long-term hospitalization. Minimizing surgical complications is thus important to preserve the quality of life of patients, and careful identification and preservation of PGs [parathyroid glands] with the blood supply in situ is accepted as necessary to protect PG function,” the researchers wrote.

Previous studies have reported that small particles (nanoparticles) made of carbon may be injected directly into the parathyroid glands to make them easier to visualize during surgery.

However, no study has yet explored whether combining this method with the parathyroid vasculature preservation technique (PVPT, a surgical technique that aims to preserve blood supply to the parathyroid glands) reduces the risk of hypoparathyroidism in patients undergoing thyroid surgery.

Investigators with Renmin Hospital of Wuhan University in China and their collaborators set out to answer this question by reviewing the medical records of 100 patients who underwent thyroid surgery between January 2016 and April 2018 at the First Affiliated Hospital Yangtze University.

Half of the patients had been injected with carbon nanoparticles directly into their parathyroid glands in combination with PVPT during surgery (group A), while the remaining 50 patients underwent standard thyroid surgery (group B, control). The levels of calcium and PTH in the serum were recorded in all participants and compared between the two groups.

Results showed that the day after surgery, patients in group A had statistically significantly higher levels of calcium (2.20 mmol/L versus 2.11 mmol/L) and PTH (33.5 pg/mL versus 25.31 pg/mL) in blood serum compared to those from group B.

Likewise, the number of patients who developed hypoparathyroidism the day after the procedure was much higher in the control group than in the experimental group (19 vs. 7 patients).

“In the present study, the incidence of transient hypoparathyroidism [14% versus 38%] and permanent hypoparathyroidism [0% versus 4%] tended to be lower in patients in group A who underwent CNs [carbon nanoparticles] injection combined with PVPT compared with patients in group B who underwent standard thyroidectomy,” the researchers wrote.

Moreover, 30 days after surgery, investigators found the levels of calcium in the serum of group A patients remained significantly higher compared to those in group B (2.27 mmol/L versus 2.21 mmol/L).

However, no statistical significant differences were found in the levels of calcium or PTH between the two groups 180 days after surgery.

“CNs injection to identify [parathyroid glands] in combination with PVPT to preserve [parathyroid glands] with blood supply in situ may decrease the incidence of post-operative hypoparathyroidism after thyroid surgery. This combined approach represents an effective method by which less experienced surgeons in particular can identify and preserve [parathyroid gland] function. However, further research of the use of CNs injection with PVPT in more thyroidectomies is required to confirm its effectiveness,”the team concluded.