Advantages and disadvantages of posterolateral approach for percutaneous endoscopic lumbar discectomy

Abstract

Background: Percutaneous endoscopic lumbar discectomy (PELD) is one of the less invasive treatments for lumbar disc herniation (LDH), and has 3 different operative approaches. This study focused on the posterolateral approach (PLA) and investigated the appropriate operative indication.

Methods: PLA was performed in 29 patients with foraminal and extraforaminal LDH. The height and width of the foramen, LDH type, and positional relationship between LDH and the foramen were radiologically evaluated. Foraminoplasty was also performed in 12 cases including those combined with intra-canal LDH or osseous foraminal stenosis. Pre- and postoperative status was evaluated using Numerical Rating Scale (NRS) scores.

Results: Patient mean age was 56.8 years; there was single-level involvement at L3/4 (13 cases) and at L4/5 (13 cases). The mean pre- and postoperative NRS scores were 6.1 and 1.8, respectively. Early recurrence developed in a patient who was found to have local scoliosis at the corresponding vertebral level.

Conclusions: PLA can be safely used to treat foraminal and extraforaminal LDH with foraminal height ≥13 mm and foraminal width ≥7 mm. The procedure is effective for preserving the facet joint; however, we should carefully consider the indications when local scoliosis and/or instability are present.

Keywords: Percutaneous endoscopic lumbar discectomy (PELD); foraminoplasty; lumbar disc herniation (LDH); minimally invasive; posterolateral approach.

Figure 1

Preoperative radiographic findings regarding the location and type of LDH. LDH is classified into 3 types according to the location of herniation on axial MRI: foraminal (A), extraforaminal (B), and combined (C). White arrowheads indicate herniated nucleus. The foraminal height (dotted line) and width (solid line) were calculated on sagittal view of preoperative CT (D).

Figure 2

Fluoroscopic images during operative procedure (case 20). Fluoroscopic images of L3/4 disc level: (A) AP view, (B-F) lateral view. Discography with indigo carmine and a contrast medium was performed and herniated disc margin was clearly delineated (white arrowheads). Following insertion of an obturator (C), a working sheath and an endoscope were inserted (D). The herniated nucleus was removed using several types of forceps and dissectors. It is necessary to tilt the working sheath to several directions for the effective removal (E, F).

Figure 3

Preoperative radiographic findings in a patient with persistent leg pain (case 8). Plain lateral radiographs of lumbar spine: (A) flexion, (D) extension; plain CT scan: (B) axial view of L4/5 disc level, (C) sagittal view of corresponding right foramen; T2-weighted MRI: (E) axial view of L4/5 disc level, (F) sagittal view of corresponding right foramen. Black arrows indicate a “vacuum phenomenon” in the right facet joint. We can also observe a “facet fluid sign” in both joints (E). Additional findings of facet joint osteoarthritis are also observed (sclerosis, osteophytes, and joint-space narrowing). White arrowheads indicate herniated nucleus.

Figure 4

Preoperative radiographic findings in a patient with degenerative scoliosis (case 4): (A) Plain anteroposterior radiograph of lumbar spine; plain CT scan: (B) axial view of L3/4 disc level, (C) sagittal view of corresponding right foramen; T2-weighted MRI: (D) coronal view showing bilateral L4 and L5 nerve roots, (E) axial view of L3/4 disc level, (F) sagittal view of corresponding right foramen. White arrowheads indicate herniated nucleus.

Figure S1

Advantages and disadvantages of posterolateral approach for percutaneous endoscopic lumbar discectomy (26). Available online: http://www.asvide.com/articles/1158