Surgeons’ Volume of Work Affects Rate of Hypoparathyroidism, Study Says

The annual rate of surgeries should increase to reduce patients’ risk of developing hypoparathyroidism after undergoing thyroid surgery, a study says.

The study, “Effect of surgeons’ annual operative volume on the risk of permanent Hypoparathyroidism, recurrent laryngeal nerve palsy and Haematoma following thyroidectomy: analysis of United Kingdom registry of endocrine and thyroid surgery (UKRETS),” was published in Langenbeck’s Archives of Surgery.

Previous studies have indicated that surgeons who perform a large number of surgeries in general have lower patient mortality rates. In addition, their patients usually stay in the hospital for shorter periods of time after the procedure, and experience fewer complications.

“Explanations for this effect include ‘practice makes perfect’ and ‘selective referral’ theories. This has influenced clinical practice, with more specialization and high-risk procedures being increasingly undertaken by high-volume surgeons,” the researchers stated.

In the case of thyroidectomies (a surgical procedure to remove the entire thyroid gland that can also damage the parathyroid glands), a surgeon must perform a minimum of 20 surgical procedures in the U.K. to remain competent. However, this specific number of procedures is not based on clear evidence.

Now, a group of physicians analyzed data stored at the United Kingdom Registry of Endocrine and Thyroid Surgeons (UKRETS) database — containing information about surgeries performed on the thyroid, parathyroid, adrenal, and endocrine pancreas glands — to look for evidence supporting the recommended number of 20 annual thyroidectomies.

The study’s primary endpoint was to determine the impact of surgery load on the number of patients who developed permanent hypoparathyroidism after undergoing a thyroidectomy.

Secondary endpoints included determining the impact of surgery load on the number of patients who developed recurrent laryngeal nerve palsy (RLN; nerve damage that affects the vocal cords and the ability to swallow) and experienced bleeding after surgery.

A total of 10,313 and 25,038 thyroidectomies were analyzed to assess the primary and secondary endpoints of the study, respectively. Results showed the annual rate of surgeries performed correlated with the number of patients developing permanent hypoparathyroidism.

Surgeons who performed fewer than 25 or between 25 and 50 thyroidectomies per year had the highest incidence rates of patients who developed permanent hypoparathyroidism (6% and 6.6%, respectively), while those who performed more than 100 surgeries per year had the lowest incidence rates (3%).

Likewise, the percentage of patients developing RLN also decreased with the annual rate of surgeries performed, from 4.4% in surgeons who performed fewer than 50 thyroidectomies per year to 2.6% among those who performed more than 100 procedures per year.

No significant correlations were found between the annual rate of surgeries and the percentage of patients who experienced bleeding episodes after surgery.

“Both [permanent hypoparathyroidism] and RLN palsy following thyroidectomy were associated with surgeon volume and declined in incidence in surgeons performing more than 50 cases/year. The results are limited by the high missing data rate in the database, but do tentatively suggest that the threshold for minimum number of thyroidectomies needed to maintain proficiency should be 50 cases/year,” the researchers stated.

“Results of this study have been presented and discussed at the BAETS annual meeting. Any recommendation for a minimum number of cases has to take into account the feasibility of delivering this service as the majority (73%) of BAETS members who contributed to this database in this study performed less than 50 cases/year and increasing specialization in thyroid surgery would inevitably result in patients traveling further distances to access surgical care,” they said.