Prospective comparative study between straight and curved probe for pedicle screw insertion.

Abstract

To evaluate difference in accuracy of pedicle screw insertion in thoracic and lumbosacral spine using a straight pedicle probe vis-à-vis a curved one. Prospective, comparative, non-randomized, single-blind study. Straight and curved pedicle probes used on opposite sides of same vertebra in patients undergoing thoracolumbar pedicle screw fixation for various indications. Postoperative blinded evaluation for pedicle breaches done with a CT scan. Pedicle breaches graded as grade 0: no breach, grade 1: <2 mm, grade 2: 2-4 mm and grade 3: >4 mm breach. After appropriate statistical power analysis, 300 screws inserted in 59 patients from T4-L5 levels. No significant differences noted between the two probes in terms of screw length [two-tailed p = 0.16]; grade 0 screws [two-tailed p = 0.49] or screws with grade 2/3 breaches [two-tailed p = 0.68]. With the right-hand-dominant operating-surgeon standing to left of patient during surgery, no difference noted between the two probes for either the right or left-side pedicle screw insertion [two-tailed p = 1]. Repeating these tests in the subset of thoracic pedicle screws too, revealed no significant difference. No significant difference in outcome of pedicle screw insertion with either a straight or a curved pedicle probe.