Wednesday January 11 2012
Middle-aged surgeons were best performers in this small study
“Middle-aged surgeons ‘are safest’”, BBC News has reported, while The Independent said: “If the surgeons [sic] young or old, put the operation on hold.”
Patients are not advised to delay any operation based on this study.
These headlines refer to a French study of patients who had all or part of their thyroid gland surgically removed. More than 3,500 operations, performed by 28 different surgeons, were analysed to look at differences in two major and permanent complications that can arise from this surgery (hypoparathyroidism and laryngeal nerve palsy).
Complications occurred in around 2–3% of operations. Overall, researchers found complication rates for hypoparathyroidism (poor function of the neighbouring parathyroid gland) were lowest in surgeons aged 35–50 years old compared with their younger and older colleagues. However, age was not related to complication rates of laryngeal nerve palsy (dysfunction of the nerves supplying the larynx).
The study looked at just one surgical procedure performed by only 28 surgeons in France. It did not provide any information on the many thousands of other surgical procedures carried out daily, or the performance of surgeons in the UK. The effect of age may vary in different settings and further research is needed to establish the facts.
The advice given by The Independent is not justified based on this study. Given that the study compared just 28 surgeons performing thyroidectomies in France, to imply that the results affect all surgeons performing all operations in the UK is unwise and potentially irresponsible.
Where did the story come from?
The study was carried out by a collaboration of investigators led by researchers at the University of Lyon, France, and was funded by the French Ministry of Health. The study was published in the peer-reviewed British Medical Journal.
The media coverage of this research was mixed. The BBC made the important point that “experts stress the studies [sic] findings are not conclusive and more investigations are needed”. However, The Independent’s apparent instruction that “if the surgeons [sic] too old, put the operation on hold” is not justified by this research and may be irresponsible. This study only looked at a single surgical technique, thyroidectomy. Delaying a thyroidectomy, or any other operation, is not justified or advisable based on this study.
What kind of research was this?
This cross-sectional analysis aimed to determine the association between surgeons’ experience and patient complications after having surgery to remove all or part of the thyroid gland (thyroidectomy).
Researchers looked at thyroidectomy because they believed the procedure is usually carried out in the same way by all surgeons and has not changed over the past decade. This meant that any differences in complications were less likely to be due to different surgical techniques being used.
What did the research involve?
Researchers looked at 28 different surgeons who performed 3,574 thyroidectomy operations between April 2008 and December 2009 in five teaching hospitals in France.
Two major and permanent complications were looked at: recurrent laryngeal nerve palsy and hypoparathyroidism. Laryngeal nerve palsy (dysfunction of the nerve supply to the larynx) can cause changes in a person’s voice. Hypoparathyroidism is a hormone disorder caused when the parathyroid glands (which lie in close proximity to the thyroid gland) don’t produce enough parathyroid hormone, which affects how calcium is used and removed by the body. Complications were assessed 24 hours after surgery and again after 6 months to establish if they were short term or more permanent.
The researchers compared thyroid procedures with and without complications to establish a list of factors that were significantly associated with higher complication rates. Factors considered were grouped into patient- and surgeon-related variables. Patient variables included:
- body mass index (BMI)
- weight of thyroid specimen removed
- complexity of the surgical case
Surgeon variables included length of experience and number of surgical procedures performed by the surgeon on the same day. Length of surgeon experience was divided into four groups for analysis:
- less than 2 years
- 2-4 years
- 5-19 years
- greater than or equal to 20 years
The average length of surgeon experience was 10 years, so the researchers compared all other groups against the 5-19 year group in the analysis.
Since patients with a high risk of complications might be cared for by more experienced surgeons, the study analysis was adjusted to take into account the complexity of each surgical case.
What were the basic results?
Laryngeal nerve palsy occurred in 2.08% of operations, whereas hypoparathyroidism occurred in 2.69% of procedures.
After adjustments were made to account for variations in complexity of the surgical case, surgeon experience of 20 years or more was the only factor significantly associated with a higher rate of complication.
Recurrent laryngeal nerve palsy was three times more likely to occur when surgeons had 20 or more years’ experience than when surgeons had 5-19 years’ experience (odds ratio [OR] 3.06, 95% confidence interval [CI] 1.07 to 8.80). The occurrence of hypoparathyroidism when the surgeon had 20 or more years’ experience was more than seven times greater than in the 5-19 year group (OR 7.56, 95% CI 1.79 to 31.99).
The researchers estimated that most of the difference between the complication rates was due to differences in patient factors (56% for laryngeal nerve palsy and 59% for hypoparathyroidism).
Approximately a tenth (10.3%) of the variation between the complication rates for laryngeal nerve palsy was due to the surgeon, whereas a third (31.5%) of the variation for hypoparathyroidism was attributable to the surgeon. Surgeon-attributable factors included length of surgeon experience and number of surgical procedures performed by the surgeon on the same day.
Overall, there was no association between laryngeal nerve palsy and a surgeon’s length of experience or age. However, age and length of surgeon experience were significantly associated with the occurrence of hypoparathyroidism. This showed that surgeons between 35 and 50 years old (with 5-20 years of practice since graduation) had better outcomes than their younger and older colleagues.
How did the researchers interpret the results?
The researchers concluded that “patients were at increased risk of permanent complications after a thyroidectomy when operated on by inexperienced surgeons or those who have spent the longest time in practice since graduation”.
They went on to say that “optimum individual performance in thyroid surgery cannot be passively achieved or maintained by accumulating experience. Factors contributing to poor performance in very experienced surgeons should be explored further”.
This research suggests that rates of hypoparathyroidism complications after thyroidectomy surgery are lowest when surgeons are aged 35–50 years old compared with younger and older colleagues. However, the surgeons’ age was not related to the complication of laryngeal nerve palsy.
This study raises the question of whether complication rates after thyroid surgery may be related to surgeon experience or age. However, significant limitations mean that these research findings may not be applicable to all surgeons or surgical procedures.
There are many issues to consider when interpreting the results. The study looked at just one surgical procedure – thyroidectomy. This study does not provide information on the many thousands of other surgical procedures carried out or those performed by surgeons from different surgical fields. The effect of age or experience in these situations may be different.
Only the two major complications of thyroid surgery were examined, and only one was found to be related to surgical experience or age (hypoparathyroidism). This suggests that not all complications will be related to surgeon experience and the association may be different in each.
The two complications examined occurred relatively infrequently, at a rate of around only 2 out of every 100 procedures for each. While the research looked at a large number of operations, this covered only a small number of complications. Analysis of such a small number of complications increases the probability that the observed associations were due to chance and decreases the accuracy of estimates. For example, though younger or older surgeons were calculated to have a seven-times higher risk of performing an operation complicated by hypoparathyroidism, the confidence interval surrounding the 7.56 odds ratio ranged from 1.79 to 31.99. This illustrates the inaccuracy of calculating results on such small numbers of complications .
The study was relatively small and assessed the performance of just 28 surgeons. Larger studies including more surgeons, which looked at other surgical specialities and different complications, would be needed to firmly establish whether surgeon age is related to complication rates.
The study did not include many middle-aged surgeons of intermediate experience. As a result, the findings may not be applicable to the more general population of surgeons whose age profile will include a large number in this group.
Surgical outcomes, including complication rates, are complex and are likely to depend on more than just the experience of the surgeon. Other factors, such as patient care after the operation, might also affect complication rates.
The study’s authors acknowledge that future studies should be conducted, with larger numbers of surgeons in different settings and examining other surgical specialities, to explore the potential link between experience and performance.
The advice given by The Independent’s headline, that “if the surgeons [sic] too old, put the operation on hold”, is not justified based on this study. The study compared just 28 surgeons performing thyroidectomies in France. To imply that the results apply to all surgeons performing all operations in the UK is unwise and potentially irresponsible.