Novel probabilistic model of core vitreous traction using microsurgical vitrectomy tools.

PURPOSE: Traction exerted on the vitreous base during vitrectomy poses a risk for retinal tears. We aimed to quantify core vitreous traction during vitrectomy using spring return and pneumatic cutters.

METHODS

Juvenile porcine vitreous was vacuum held in a vitreous bath while traction was measured using precision force gauge during vitrectomy. The parameters included were aspiration rate, cut-rate, cutter size, and machine types.

RESULTS

An empirical probabilistic model was developed. The traction was proportional to the aspiration rate but insignificantly dependent on the cut-rate. The traction probability was inversely proportional to the exponential function of the traction (p < 0.05). The traction was < 0.003 N for 99% of the time using either 23- or 25-gauge cutters.

CONCLUSION

The tractions measured were considered similar to the causative forces of an iatrogenic retinal tear during a pars plana vitrectomy. The results provide a safety reference matrix of instrumental parameters during vitrectomy.