An article published in the Journal of Spinal Disorders & Techniques examines pedicle screw breaches for percutaneous screw placement.
The researchers examined 151 patients after instrumented single-level or two-level minimally invasive transforaminal lumbar interbody fusion. There were 601 screws placed for percutaneous fixation, and most were single-level procedures. The average patient age was 56.6 years old.
Previous articles in the literature have varying results for pedicle breachs; among open procedures, rates have been as high as 29 percent. The computer-assisted two-dimensional fluoroscopy-guided procedures have breach rates as high as 23 percent in the litareture, and a series of 225 pedicles instrumented with three-dimensional fluoroscopy reported a breach rate at 1.8 percent.
Findings for this study include:
1. There were 27 pedicle breaches, or 6.2 percent of the pedicles were breached. There were 22 that were significiant breaches.
2. The level of breached pedicles were:
L3: 10.2 percent
L4: 7 percent
L5: 9.5 percent
S1: 3.4 percent
3. The side locatin also made a difference. The breaches broken down by side were:
Medial: 22
Lateral: 12
Superior: two
Inferior: one
4. Of the two symptomatic breaches, both were assicated with the medial breach at the L5 pedicle.
5. The symptoms from the pedicle breaches were transient and didn't require hardware repositioning. There were no other complications.
"The use of intraoperative fluoroscopic guidance is both a clinically safe and accurate method for instrumentation and is of comparable accuracy to other techniques," concluded the study authors. "Although trajectory errors may occur, they are of rare clinical significance."