April 2019


Presentation spotlight
Correlation in capsule complications, operation volumes in Sweden

by Stefanie Petrou Binder, MD EyeWorld Contributing Writer

A Swedish study that analyzed changes in the incidence of capsule complications with high volume cataract surgeons during a 10-year time interval and the impact of operation volume per surgeon and clinical unit on the rate of capsule complications reported its outcomes during the 36th Congress of the European Society of Cataract and Refractive Surgeons. The study related capsule complications that occur during the course of cataract surgery directly to the individual surgeon’s surgical volume, not to the volume of surgeries performed at an individual surgical eye unit.
This Swedish National Cataract Register- based study incorporated data from all cataract operations performed between 2007 and 2016. The change in operation volume per surgeon was determined over time and the incidence of capsule complications was correlated to the operation volume of individual surgeons and clinical units.

Low to high volume surgeons

Data showed the majority of surgeons performed between 100 and 500 cataract procedures per year between 2007 and 2016. In 2007, roughly 150 surgeons performed 100 to 499 cataract procedures per year, which sunk to about 120 surgeons performing that volume in 2016.
There was a minor increase in the proportion of high volume and very high volume surgeries toward the end of the study period. While only about 20 surgeons performed between 500 and 999 cataracts in 2007, this rose to 60 in 2016.
The numbers of surgeons performing less than 100 or more than 1,000 surgeries per year remained steady within the 10-year time period.
“When looking at the high volume cataract surgeons in 2007, 15% of the surgeons performed 500 or more cataract procedures,” said Madeleine Zetterberg, MD. “In 2016, this proportion had increased to 34% of the surgeons performing in excess of 500 cataract procedures. Only 2.1% of Swedish surgeons performed more than 1,000 cataract procedures in 2007 compared to 10.9% in 2016.”
While the majority of cataract surgeons performed between 100 and 500 procedures a year, the proportion of the total surgical volume decreased significantly from 60% to 30%. High volume and very high volume surgeons performed a large proportion of the total surgical volume within this 10-year space.
In 2007, almost 37% of the total cataract volume was performed by high volume cataract surgeons. In 2016, they carried out 68%. Very high volume surgeons performed 8.7% of the total cataract volume in 2007, and in 2016 they were responsible for 33%.

Correlation between volume and incidence of capsule complications

Dr. Zetterberg found a 1% complication rate for posterior capsule rupture corresponded to 401 cataract procedures per surgeon. “There were more complications in surgeons doing fewer procedures. When looking at different category volumes, the low volume surgeons had a posterior capsule rupture rate of a little more than 2%, and the medium volumes surgeons had rates of a little more than 1%. Capsule rupture had about a 1.5% incidence for the high volume surgeons,” she said.
In 2007, a mean number of 300 procedures were performed per surgeon. This number rose to 450 procedures per surgeon per year, reflecting a drop in the mean rate of posterior capsule ruptures from 1.5% to 0.8% during the study period.
A previous report from the Swedish register noted that high volume surgical units had fewer complications than low volume units. In the current study, the investigators could not establish this correlation. There was no statistically significant difference in the complications seen with increasing operation volume per clinical unit.
Dr. Zetterberg said a slight bias existed pertaining to the types of cataracts performed at high and low volume units. “The parameters associated with capsule rupture were low preop visual acuity and pseudoexfoliation and ocular comorbidity. We had surrogate markers for loose lenses, small pupils, and dense cataracts. We created a composite risk score and looked at the case mix at the different volume categories, and we found that there seemed to be higher, more difficult cases for the medium and low volume cataract surgeons,” she said.

About the doctor
Madeleine Zetterberg, MD

Sahlgrenska University Hospital
Mölndal, Sweden

Financial interests
: None

Contact information
: madeleine.zetterberg@gu.se

Correlation in capsule complications, operation volumes in Sweden Correlation in capsule complications, operation volumes in Sweden
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