Forceps that 'sense' may help assess surgeons' skills

Reuters Health Information: Forceps that 'sense' may help assess surgeons' skills

Forceps that 'sense' may help assess surgeons' skills

Last Updated: 2017-11-21

By Marilynn Larkin

NEW YORK (Reuters Health) - Forceps that sense tool-tissue interactions may help determine a surgeon's skill level, which could improve outcomes and enhance surgical education, researchers suggest.

"Traditionally, trainees have learned the nuances of surgical skill through case observation and have received largely qualitative feedback on performance from their mentors," note Dr. Garnette Sutherland of University of Calgary in Canada and colleagues.

"As the apprenticeship model of surgical education evolves toward a more competency-based paradigm, there is need to devise sensitive and reliable methods for objective assessment of surgical skill," they add.

To advance that effort, Dr. Sutherland developed force-sensing bipolar forceps by installing strain-gauge sensors in the tool.

He told Reuters Health that a driving force behind developing the device was his work years ago as a resident under pioneering Canadian neurosurgeon Charles Drake.

"I marveled at his ability to manipulate tissues seamlessly, not causing any injury to the surrounding eloquent structures," Dr. Sutherland said in an email.

"Fast-forwarding several decades, working with (an) image-guided robot, I was able to appreciate the forces of tool-tissue interaction as a digital record of surgery," he observed.

"I sat down with my engineering team and pondered the challenge of installing force sensors onto the prongs of conventional bipolar forceps, a tool most commonly used in neurosurgery," he continued.

"(We) . . . translated the technology into the neurosurgical operating room, (and) the first 26 cases form the foundation of the (current study)," he explained. "We discovered that expert surgeons use similar forces to accomplish surgical tasks, and based on this, force analysis was able to discriminate surgeons by skill level."

The current study included 26 patients (38% male; mean age, 43) undergoing neurosurgery by 16 surgeons, who were grouped by skill level: six in the novice group, five in the intermediate group, and five in the experienced group.

Normative baseline force ranges were obtained using the force profiles - mean and maximum forces and force variability - from the experienced surgeons.

Standardized force profiles and force errors - high force error, low force error, and force variability error - were analyzed and compared among surgeons with different skill levels. Each trial with the forceps was deemed successful or unsuccessful.

Data from 10 common surgical tasks were selected for comparison, and for each trial the surgeons stated the tasks being performed.

As reported in JAMA Surgery, online November 15, the finding that a trial was unsuccessful because it was incomplete significantly correlated with low force errors and force variability errors, whereas an unsuccessful trial because of bleeding correlated with high force errors and force variability errors.

The mean force strengths exerted by novice surgeons were significantly higher than those of experienced surgeons (0.74 Newtons vs. 0.00N), and mean force variability decreased from novice (0.43N) to intermediate (0.28N) to experienced (0.00N) surgeons; however, these differences varied among surgical tasks.

The rate of high force errors inversely correlated with surgeon level of experience: 0.27N for novice, 0.12N for intermediate, and 0.05N for experienced surgeons.

Similarly, force variability errors were 0.16N for novice, 0.10N for intermediate, and 0.05N for experienced surgeons.

The mean rate of low force errors was significantly higher in intermediate (0.12N) and novice (0.10N) surgeons, compared with experienced ones (0.04N). Low force errors did not differ between intermediate and novice surgeons.

"Stepwise discriminant analysis revealed that combined use of these error rates could accurately discriminate the groups" more than 87% of the time, the authors state.

Dr. Sutherland said, "The findings are important, as such tools provide a digital footprint of surgical procedures that we presently lack, and through a feedback mechanism, prevent untoward force error, advancing surgery towards standardized care and competency-based skill assessment."

Dr. Garni Barkhoudarian, a neurosurgeon at John Wayne Cancer Institute at Providence Saint John's Health Center in Santa Monica, California, commented, "Any additional method to objectively assess surgical skill is helpful to assess neurosurgical residents. The surgical forceps developed by the authors does accomplish this to a certain extent."

However, "the study is very small, only assessing a handful of surgeons in each arm," he told Reuters Health by email. "A much larger study is necessary to truly validate this technology."

"Additionally, the design of the forceps itself affects the measurements," he explained. "Forceps are deliberately designed to be stiff or loose based on the purpose of the surgery - e.g., a tumor-resection forceps needs much more opening force and will be quite stiff, but a vascular forceps needs to be gentler and has a lower opening force. These were not addressed with this single forceps system."

"Also, the wires on the back end of the device may cause additional force that needs to be counteracted by the surgeon's hands - i.e., the balance of the forceps is shifted compared to a typical microdissection forceps," he said. "Nevertheless, there are notable differences between the three groups, and hence there is some value generated by this comparison."

He concluded, "I commend the authors for embarking on this initiative and look forward to the further assessment of this device."

All of the study authors were involved in the development of force-sensing forceps and are now working toward its commercialization.


JAMA Surg 2017.

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