Navigation-assisted extraforaminal lumbar disc microdiscectomy: Technical note

Abstract

Background: Extraforaminal lumbar disc herniation (ELDH) amounts of 7%-12% of all lumbar disc herniations. Although they have already been widely described, an optimal treatment is still under discussion in the literature.

Objective: We describe a novel application of navigation using 2D/3D imaging system to plan an adequate surgical trajectory and performing a neuronavigated microdiscectomy in ELDH that has not been previously described.

Methods: This is a retrospective study in a single institution. Between February 2017 and July 2020, a total of 12 patients (7 males and 5 females), with a mean age of 56 years (range 49-71 years), have been treated because of ELDH through a far lateral microdiscectomy using 2D/3D imaging system-assisted neuronavigation (O-arm).

Results: No intraoperative and/or postoperative complications were recorded. Patients presented a mean preoperative Visual Analog Scale (VAS) score of 7.83 ± 0.83 (range 7-9). At the day of discharge, leg pain VAS score effectively improved, decreasing to a mean value of 1.83 ± 0.83 (range 1-3). Further, low back and radicular pain improvement was recorded at 1-, 6-, and 12-month follow-up, respectively.

Conclusion: We described a novel use of 2D/3D imaging system navigation in the microsurgical treatment of ELDH that has not previously reported. This technique is safe and effective and provides more intraoperative details compared to fluoroscopy, which can be crucial for the success of the procedure and to reduce complications and particularly indicated in complex cases with altered anatomy.

Keywords: Extraforaminal; Navigation; O-arm; lumbar disc herniation; microdiscectomy.

Figure 1

Multiplanar reformation images showing the correct positioning of the pin to the right posterior superior iliac spine to place the reference frame

Figure 2

Antero-posterior projection showing the correct positioning spinal needle identify the correct left L3–L4 intertransverse space and neuroforamen (Left, yellow asterisk) Preoperative coronal and axial T2-weighted magnetic resonance imaging images showing pure left L3–L4 extraforaminal lumbar disc herniation (center and right, yellow asterisks)

Figure 3

Preoperative checking of navigation accuracy touching with the tip of the probe the pin surface of the reference frame

Figure 4

Intraoperative checking using the pointer and a virtual tip offset of variable length to choose the correct surgical trajectory and to identify the anatomic landmarks

Figure 5

Intraoperative images showing extraforaminal lumbar disc herniectomy. The disc fragment was mobilized with a hook and removed with pituitary pounches. The exploration along the nerve route showed no evidence of nerve impingement, with a pulsating and decompressed nerve root

Figure 6

Postoperative axial (up) and sagittal (down) T1-weighted magnetic resonance imaging images showing left L3–L4 extraforaminal lumbar herniectomy