Laser Fibers for Urological Surgery Don’t Conform to Standard Measurements

In lasers used for urological surgery, the total and core diameters of laser fibers do not correspond to the advertised laser fiber diameter, according to the results of a new study that aimed to objectively confirm the diameter between laser fibers of supposed equal thickness by different brands.

The results of the study were presented earlier this month at the 2nd Meeting of the European Association of Urology’s Section of Urolithiasis in Copenhagen, Denmark. An additional study finding was that there are serious differences between manufacturers of fibers with a supposedly equal diameter.

This is an important finding, because larger-than-advertised laser fibers can influence irrigation flow, visibility, scope deflection, and stone retropulsion, the researchers explained. Urologists need to know the exact technical specifications of the material they use.

“If the information conveyed to them, whether written on a product label or transmitted by an industry representative, is incorrect, their judgments and the decisions they make based on this knowledge may have surgical repercussions,” said study researcher Dr Peter Kronenberg of Hospital Fernando Fonseca in Amadora, Portugal.

Fourteen different brand-new laser fibers, both single- and multi-use, representing 6 leading brands were examined with light microscopy. The advertised diameters of the the laser fibers were 200, 270, 272, 273, 365, and 400 micrometers. Multiple measurements of the total diameter, which included the fiber coating, and of the fiber core diameter were performed. These measurements were compared with the respective advertised diameter. A 10% deviation from the manufacturer’s advertised measurements was considered acceptable.

Both the total and core diameters of all 14 laser fibers were significantly different from the advertised diameters (P<0.00001). If the advertised diameter is considered the total diameter, than none of the fiber lasers were within the 10% tolerance range. If the advertised diameter is considered the fiber core diameter, then only 1 fiber laser was within the 10% margin of tolerance.

The median increase between total diameter and advertised diameter was 85.3%, and 4 of the fiber lasers were more than double as thick as indicated. For the fiber core diameter, the median increase from the advertised diameter was 30.9%. When comparing core diameters of fibers advertised to be of equal size, the researchers detected differences of up to 100 micrometers.

These findings implicate that a review of the technical specifications of other devices may be warranted, said Kronenberg.

Pertinent Points:
- The total and core measurements of 14 laser fibers used for urological surgery do not correspond to the advertised diameters or to standard measurements.
- The median increase between total diameter and advertised diameter was 85.3%.
- For the fiber core, the median increase between the core diameter and the advertised diameter was 30.9%.

References:

Kronenberg P, Traxer O. The truth about laser fiber diameters. Abstract E60. 2nd Meeting of the EAU Section of Urolithiasis (EULIS). September 5-7, 2013. Copenhagen, Denmark.