Study Design: Prospective clinical study.
Objectives: Although percutaneous pedicle screw fixation continues to be increasingly practiced, there remain few reports specifically addressing the accuracy and clinical safety of this technique. The goal of this study is to evaluate the accuracy of fluoroscopically guided pedicle screw placement in the lumbar spine.
Summary of Background Data: Pedicle breach rates vary substantially in the literature. Pedicle breach rates have been reported to be as high as 29% with the traditional, open technique. With the use of computer-assisted 2D fluoroscopy, breach rates have been reported between 5-23%. Furthermore, in a series of 225 pedicles instrumented with 3D fluoroscopy, the reported breach rate was 1.8%.
Methods: A total of 151 patients were evaluated following instrumented single-level or two-level minimally invasive TLIF with 601 screws placed for percutaneous fixation. The treated patients had an average age of 56.6 (20-85) and there were 129 single-level cases and 22 two-level. The levels of pedicle screw fixation included (Level, pt no.): L1/L2 (1), L2/L3 (2), L3/L4 (33), L4/L5 (101), L5/S1 (46). Radiographic results included post-operative CT scan. Patients were followed prospectively for potential clinical symptoms.
Results: In a total 601 instrumented pedicles, there were 37 pedicle breaches (6.2%). Of these, 22 (3.7%) were significant breaches (>= 3[medium shade]mm). The level of the breached pedicles were L3 (5/46, 10.2%), L4 (12/201, 7.0%), L5 (15/158, 9.5%), S1 (3/47, 3.4%). The side/location of breach was characterized as follows: Medial (22), lateral (12), superior (2), and inferior (1). There were two symptomatic breaches, both associated with a medial breach at the L5 pedicle. Symptoms from these events were transient and did not require hardware repositioning. There were no other complications.
Conclusions: Percutaneous pedicle screw fixation in the lumbar spine continues to be a technique embraced by modern spinal surgeons. The use of intra-operative fluoroscopic guidance is both a clinically safe and accurate method for instrumentation and is of comparable accuracy to other techniques. While trajectory errors may occur, they are of rare clinical significance.
(C) 2013 by Lippincott Williams & Wilkins, Inc.