4.11. Features of herniation removal through a contralateral approach

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Most surgeons prefer to work from the patient’s left side. When decompression and discectomy need to be combined, I may therefore consider removing a right-sided disc herniation through a left-sided approach. The initial stages up to partial resection of the ligamentum flavum correspond to those described in the preceding sections.

To cross to the opposite side, I perform additional bone resection of the bases of the proximal and distal spinous processes, contralateral lamina, and contralateral superior articular process.

Step-by-step technique

First, I identify the base of the proximal spinous process. With a blunt dissector — an elevator — I carefully detach the ligamentum flavum. It protects intracanal neural structures, so I preserve it until the final stages of bone resection. I position the cutting burr beneath the spinous process and perform partial resection. After approximately 3–5 mm of bone has been removed, the contralateral lamina should become visible.

Alternating the elevator to detach the ligament with the burr, I expose and partially resect the bony lamina. After sufficient resection of the proximal contralateral lamina and contralateral inferior articular process, the contralateral superior articular process becomes visible. In the same way, I detach the ligament and undercut the base of the distal spinous process. I must clearly identify the transition from the distal lamina to the superior articular process on the contralateral side.

With 2–3 mm Kerrison punches, I create a small notch near the base of the contralateral superior articular process. It serves as a landmark for the safe zone. I then bluntly detach the contralateral ligamentum flavum from the lamina and superior articular process.

Hemostasis

Bleeding from bone may occur during bone resection. For hemostasis, I use a coagulation electrode in ablation mode or bone wax.

I gently warm the wax in my hands and apply a small amount to the elevator. I use the elevator to press the wax onto the bleeding bone surface.

Resection of the ligamentum flavum

The midline interval between the right and left portions of the ligamentum flavum should usually be visible. I carefully insert the elevator into this interval and, under direct visualization, slowly detach the ligament from the underlying dura mater. I then remove the ligamentum flavum in pieces with up-angled Kerrison punches or delicate rongeurs. I work slowly and check each time that the dura mater has not been grasped.

This stage requires particular attention because of the risk of injury to the nerve root sheaths or the nerve root itself.

After removing the contralateral portion of the ligamentum flavum, I visualize the dural sac and the traversing and exiting nerve roots. Under direct visualization, I place the elevator on a clearly identified bony surface or disc surface and carefully mobilize the dural sac and traversing nerve root medially. At this stage, I identify and expose the herniated fragment.

During herniation removal, I protect the nerve root with a nerve root retractor. I handle neural structures gently and pause retraction to reduce the risk of postoperative hypoesthesia.

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Epidural bleeding and its control

On entering the epidural space, bleeding may increase and impair visibility.

1. Systemic factors. If bleeding increases or outflow deteriorates, I pause and check irrigation, fluid outflow, and the patient’s hemodynamic status. The anesthesiologist determines whether adjustment of arterial pressure or anesthesia is appropriate; we do not automatically lower pressure or administer additional muscle relaxants.
2. Epidural bleeding. I perform targeted coagulation under direct visualization with continuous irrigation and unobstructed outflow. In my practice, near the dura mater or nerve roots, I use COAG 2 on the BONSS ARS600 scale; this is a console level, not power in watts. I protect neural structures with a separate instrument without applying energy and direct the active surface only toward the target bleeding tissue.
3. Detaching the ligamentum flavum. Under direct visualization, I use a dissector without energy delivery to identify a safe plane between the ligament and underlying dura mater. I do not use an activated RF electrode to separate adherent ligament from neural structures. If bleeding requires coagulation, I follow the precautions described above and restore clear visibility before continuing.

References

1. Park DK, Weng C, Zakko P, Choi DJ. Unilateral biportal endoscopy for lumbar spinal stenosis and lumbar disc herniation. JBJS Essent Surg Tech. 2023;13(2):e22.00020. doi:10.2106/JBJS.ST.22.00020.

2. Kim SK, Kang SS, Hong YH, Park SW, Lee SC. Clinical comparison of unilateral biportal endoscopic technique versus open microdiscectomy for single-level lumbar discectomy: a multicenter, retrospective analysis. J Orthop Surg Res. 2018;13(1):22. doi:10.1186/s13018-018-0725-1.

3. Choi CM. Biportal endoscopic spine surgery (BESS): considering merits and pitfalls. J Spine Surg. 2020;6(2):457–465. doi:10.21037/jss.2019.09.29.

4. Saugel B, Fletcher N, Gan TJ, et al; POQI XI Workgroup. PeriOperative Quality Initiative (POQI) international consensus statement on perioperative arterial pressure management. Br J Anaesth. 2024;133(2):264–276. doi:10.1016/j.bja.2024.04.046.

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