Trans-Tubular Translaminar Microscopic-Assisted Nucleotomy for Lumbar Disc Herniations in the Hidden Zone

Abstract

Study design: A prospective cohort study in a high-flow spine center in Germany.

Objectives: This study aimed to evaluate clinical outcomes and complications of the trans-tubular translaminar microscopic-assisted percutaneous nucleotomy in cases of cranially migrated lumbar disc herniations (LDH).

Methods: Between January 2013 and January 2018, 66 consecutive patients with cranio-laterally migrated LDH were operated upon. The following outcome measures were evaluated: (1) Visual Analog Scale (VAS) for leg and back pain; (2) Oswestry Disability Index (ODI) and Macnab´s criteria. All patients were operated upon with trans-tubular Translaminar Microscopic-assisted Percutaneous Nucleotomy (TL-MAPN). Perioperative radiographic and clinical evaluations were reported. The mean follow-up period was 32 months.

Results: The mean age was 59 years. L4/L5 was the commonest affected level (27 patients). The mean preoperative VAS for leg pain was 6.44 (±2.06), improved to 0,35 (±0.59) postoperatively. Dural injury occurred in 1 patient, treated with dural patch. Improved neurological function was reported in 41/44 Patients (neurological improvement rate of 93%) at the final follow up. There was a significant improvement in the mean ODI values, from 50.19 ± 4.92 preoperatively to 10.14 ± 2.22 postoperatively (P < 0.001). Sixty four out of 66 patients (96%) showed an excellent or good functional outcome according to Macnab´s criteria. No recurrent herniations were observed.

Conclusion: The translaminar approach is a viable minimal invasive technique for cranially migrated LDH. The preservation of the flavum ligament is one of the main advantages of this technique. It is an effective, safe and reproducible minimally invasive surgical alternative in treatment of cranially migrated LDHs.

Keywords: cranially migrated disc; discectomy; lumbar disc herniation; minimal invasive; trans-laminar trans-tubular.

Figure 1.

Preoperative MRI of a 45 year-old man, showing cranially migrated sequestration L4/5 on the left side.

Figure 2.

Intraoperative images on the image intensifier showing localization of the level in antero-posterior and lateral view using a 1.5 mm high speed burr just penetrating the outer cortex of the lamina and then the 90-degree hook introduced through the fully prepared laminotomy hole. The hook is placed lateral to the dural sac and behind the vertebral body cranial to the disc space.

Figure 3.

Intraoperative images showing the tube system used fixed to the operative table. The incision after closure and the fragment removed are also shown.

Figure 4.

A) The operative field under microscope with the yellow circle encircles the laminotomy hole, while the ligamentum flavum is still in place. B) The dural sac is seen after removal of the ligamentum flavum. C) Part of the sequestrated fragment can be seen after medial retraction of the dural sac and hemostasis using a cottonoid patty laterally. D) The removed sequestrated fragments.

Figure 5.

A) Postoperative CT sagittal and axial reconstructions showing the drilled hole in the laminaof L4. B) The pre- and postoperative plain x-ray showing the hole in the lamina on the left image. C) The 3D and coronal reconstruction of the postoperative CT showing clearly the perserved upper and lower border of the lamina and the intact pars interarticularis. D) Postoperative MRI shows the complete removal of the sequestrated disc and the minimal muscle trauma.