2.3. Incision
@ProfFishchenkoPrevious section: 2.2. Planning
Incision direction and size
When planning the incisions, I assess the approach trajectory, soft tissue thickness, diameter of the endoscope and instruments, conditions for free irrigation fluid outflow, and the possibility of extending the approach.
In my practice, I usually make longitudinal skin incisions 7–10 mm in length; the working incision may be larger if needed. I adapt the dimensions to the specific system, instruments, and soft tissues.
I anticipate the possibility of conversion to microsurgical or open surgery before starting the procedure, particularly while learning the technique. I do not automatically join the two portal incisions: the direction and extent of exposure depend on the anatomy and the reason for conversion.
In some cases, a transverse incision along the natural skin tension lines may leave a less noticeable scar. However, cosmetic considerations must not take precedence over a safe trajectory, free instrument movement, fluid outflow, and the possibility of extending the approach.
Endoscopic portal
I create the endoscopic portal first. I incise the skin with a pointed No. 11 scalpel, then make a longitudinal fascial incision while controlling depth.
I then sequentially dilate the muscular tract bluntly with dilators down to the bony landmark, after which I place the trocar. I select the number and diameter of the dilators according to the specific set and the required size of the portal tract.
Working portal
I move approximately 2–3 cm from the endoscopic portal: caudally for a left-sided approach or cranially for a right-sided approach. I refine this distance according to soft tissue depth, the anatomical target, and the planned instrument trajectories.
After incising the skin, I always make a cruciate incision in the fascia of the working portal while controlling depth to ensure free outflow. I sequentially dilate the muscular tract bluntly with appropriately sized dilators down to the bony landmark.
I establish triangulation by directing the endoscope and working instrument through independent portals toward a common anatomical target. I check for free instrument movement and continuous fluid outflow. If outflow is impaired, I remove the mechanical obstruction in the portal tract rather than compensate by increasing pressure.
Video demonstration
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. Choi CM, Chung JT, Lee SJ, Choi DJ. How I do it? Biportal endoscopic spinal surgery (BESS) for treatment of lumbar spinal stenosis. Acta Neurochir (Wien). 2016;158(3):459–463. DOI: 10.1007/s00701-015-2670-7.
3. Zhang Q, Wei Y, Wen L, Tan C, Li X, Li B. An overview of lumbar anatomy with an emphasis on unilateral biportal endoscopic techniques: A review. Medicine (Baltimore). 2022;101(48):e31809. DOI: 10.1097/MD.0000000000031809.
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