Endoscopic MIS-TLIF with Destandau’s system: leveraging endoscopy with conventional instruments

This presentation showcases an endoscopic minimally invasive spine surgery (MISS) technique for lumbar interbody fusion. Significantly expanding the scope of Destandau’s system within MISS, it serves as a pivotal link to unilateral biportal endoscopy (UBE) for endofusion. The method involves minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) using a 4-mm rigid endoscope through Destandau’s system. With the widespread familiarity with Destandau’s system and the absence of specialized instrument requirements, this approach is easily adoptable, particularly in resource-limited centers. The favorable clinical and radiological outcomes underscore the effectiveness of this technique, propelling the role of endoscopy in MISS, particularly in endofusion. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23216

2:39 Three-Point Drilling.The rest of the lower lamina is drilled at three strategic points using a 3-mm diamond burr.Firstly at the lower margin.Secondly at the junction of the pars interarticularis and the inferior facet by working laterally from the first point.This would help resection of the L5 inferior facet.And lastly at the root of the spinous process to allow over-the-top decompression of the spinal canal and the contralateral nerve root.The remaining bone is removed with a Kerrison punch.
3:08 Inferior Facet Resection As the pars interarticularis and the inferior facet junction was removed with the Kerrison's punch, the whole of the inferior facet could be disconnected.The disconnection of the L5 inferior facet entails a careful separation from its ligamentous attachment.Utilizing biopsy forceps, it was divided into two halves so as to deliver it through the outer sheath.These bone pieces can be used to pack the polyetheretherketone (PEEK) cage to improve fusion rates.
3:34 Removal of the S1 Superior Facet.Now the facetal surface of the S1 facet is seen.This facet is removed using No. 3 Kerrison punch, working medial to lateral until we reach the S1 pedicle.The surface is smoothened using a burr while avoiding any injury to the pedicle.4:45 Discectomy.The lower part of the Kambin's triangle was thus exposed.Using a 15 No. blade, the annulus is cut.The nucleus pulposus and part of the annulus fibrosus are removed using biopsy forceps.Care is taken to remove all the herniated disc, including the migrated portion.
5:07 Insertion of the Second Port.A 1.5-cm horizontal incision was made at the marked level for inserting the L5 percutaneous pedicle screw (PPS).This incision is deepened till the fascia.The first of the dilators for PPS is inserted, and sounding is done with the Destandau's outer sheath to confirm alignment.The dilator is further navigated into the disc space under endoscopic vision.Triangulation of the instruments is thus achieved.
Successively, the second dilator is then inserted, followed by the third dilator sheath, which is used for screw insertion.It is inserted until its lower margin is just visible by the endoscope and left in situ to act as a new port.
The endoscope is then inserted in this new port.The inner sheath of the Destandau's system is removed, allowing the outer sheath to serve as an access port for the larger instruments to be introduced into the disc space.
6:07 Endplate Preparation.Larger shavers can now be inserted through the Destandau's outer sheath to prepare the disc space like in tubular discectomy.The endoscope can be freely advanced into the disc space to inspect the status of the endplate preparation.
6:26 Sizer Followed by Cage Insertion.The sizer for the cage was inserted under endoscopic vision, thus preventing nerve injury.Due to the transforaminal corridor, only a slight retraction of the traversing nerve root is required when using a large cage.
A 14 × 28-mm PEEK cage was inserted and its position was confirmed on the C-arm.For adequate visualization of the nerve root on the medial aspect of the cage, a 30° endoscope is required at times.The dislodged bone chips from the cage and remaining disc fragments were removed.At the end of the procedure, the L5-S1 left lateral recess and foramina were completely free.
7:10 Over-the-Top Decompression.The spinal canal and the contralateral nerve root were decompressed by the over-the-top technique.The thecal sac and the traversing nerve root (S1) can be seen to be well pulsatile and supple, confirming no compression.Afterward, L5-S1 PPSF was done.
7:29 Postoperative Status.The patient was ambulated 12 hours after the surgery.She was now able to walk without pain.There was a complete improvement in the left EHL power by the 3rd week of follow-up.Postoperative CT affirmed correction of the listhesis with optimal implant position.The total operative time was 4.5 hours, with an estimated blood loss of 300 ml.The patient was discharged in 5 days with significant improvement in the VAS scores.
The technique has its own benefits, nuances, and limitations.It expands the spectrum of Destandau's system and is a bridge to unilateral biportal endoscopy, thus increasing the role of endoscopy in minimally invasive spine surgeries.

3 :
49 Resection of Ligamentum Flavum.The ligamentum flavum is then removed in piecemeal.It will expose the underlying epidural fat.It should be retained till all the bony work is completed to avoid a dural tear.4:00 Dural Exposure.Removal of the epidural fat exposes the thecal sac.4:07 Exposure of the Traversing Nerve Root.Working laterally to the thecal sac in a craniocaudal direction, the fat and soft tissue are dissected to expose the traversing nerve root.4:25 Exposure of the Disc.The traversing nerve root is gently retracted medially at its shoulder to expose the disc space.The Destandau's retractor is used to keep the nerve root retracted.The engorged epidural veins are coagulated and cut.4:40 Confirmation of Disc Level.Using a marking needle, the disc level is confirmed under the C-arm.