Total 3D Airo® Navigation for Minimally Invasive Transforaminal Lumbar Interbody Fusion

Abstract

Introduction. A new generation of iCT scanner, Airo®, has been introduced. The purpose of this study is to describe how Airo facilitates minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Method. We used the latest generation of portable iCT in all cases without the assistance of K-wires. We recorded the operation time, number of scans, and pedicle screw accuracy. Results. From January 2015 to December 2015, 33 consecutive patients consisting of 17 men and 16 women underwent single-level or two-level MIS-TLIF operations in our institution. The ages ranged from 23 years to 86 years (mean, 66.6 years). We treated all the cases in MIS fashion. In four cases, a tubular laminectomy at L1/2 was performed at the same time. The average operation time was 192.8 minutes and average time of placement per screw was 2.6 minutes. No additional fluoroscopy was used. Our screw accuracy rate was 98.6%. No complications were encountered. Conclusions. Airo iCT MIS-TLIF can be used for initial planning of the skin incision, precise screw, and cage placement, without the need for fluoroscopy. "Total navigation" (complete intraoperative 3D navigation without fluoroscopy) can be achieved by combining Airo navigation with navigated guide tubes for screw placement.

Figure 1

(a) iCT position during the procedure. (b) iCT position during active scan. (c) Skin incision planning. (d) The navigated guide tube allows dilating, drilling, tapping, and screw placement all through one navigated instrument. (e) Placement of pedicle screw. (f) Placement of tubular retractor with the insistence of navigation. (g) Determining extent of decompression by navigation. (h) Bone harvesting from iliac crest under guidance of navigation. (i) Cage planning. (j) Rod measurement from the screen of navigation station.

Figure 2

A 63-year-old female with two-level stenosis and instability. Pre-op MRI showed foraminal stenosis of left side in L4/5 (a) and right side in L3/4 (b). From navigation screen, foraminal heights were measured preoperatively and postoperatively. L3/4 and L4/5 of left side increased from 19.6 mm and 11.7 mm to 21.3 mm and 17.4 mm, respectively (c). L3/4 of right side increased from 17.7 mm to 20.1 mm (d). L4/5 of right side increased from 18.5 mm to 20.8 mm (e). The disc height of L3/4 and L4/5 increased postoperatively (f). The local lordosis improved postoperatively (g).