7.4. Bone Resection
@ProfFishchenkoDecompression for lateral recess stenosis includes resection of the medial portion of the superior articular process (SAP) and the adjacent portion of the ligamentum flavum. To access these structures, I first partially resect the cranial lamina and inferior articular process (IAP). I determine the extent according to the anatomy and adequacy of decompression, preserving supporting structures.
In my practice, I use a 5 mm cutting burr with the Stryker CORE 2 system. Bone resection may also be performed with an osteotome when the surgeon has appropriate experience. When learning BESS/UBE, I recommend starting with a burr. Regardless of the instrument selected, I ensure direct visualization and protection of neural structures.
Resection of the cranial lamina
I begin bone resection with a 5 mm burr at the lamina of the cranial vertebra, gradually moving toward its IAP. I do not resect the full width of the lamina at once: I thin it layer by layer, first the superficial layer by approximately 3–5 mm, then the middle layer. I determine the depth of each pass according to the actual bone thickness and visual control. I may remove the deep layer using 3 mm, 45° Kerrison punches or continue with the burr when visualization is sufficient. I introduce the lower jaw only in a clearly identified plane between the bone and the separated ligamentum flavum, without blind advancement or forceful displacement. The preserved ligament serves as an additional protective layer; I perform all maneuvers under direct visual control. The aim at this stage is to visualize the tip of the ipsilateral SAP; reaching the cranial attachment of the ligamentum flavum is unnecessary for this purpose.
After resecting the cranial lamina, I move laterally toward the IAP. I resect approximately 4–5 mm of its medial portion to visualize the medial edge of the SAP from tip to base. I determine the final extent according to the adequacy of decompression and preservation of the joint.
Using 3 mm, 45° Kerrison punches, I perform a small resection of the SAP base, approximately 3 mm. At this stage, I try to preserve the ligamentum flavum as an additional protective layer over neural structures.
Resection of the caudal lamina
Using the burr, I thin the superficial layer of the caudal lamina from the base of the caudal spinous process to the base of the SAP; the guide given in this technique is 4–5 mm, taking actual bone thickness into account. I remove the deep layer using reverse 45° or 90° Kerrison punches down to the ligamentum flavum attachment.
The caudal edge of the ligament usually attaches near the edge of the lamina. In the presence of marked degenerative changes, additional limited resection with the burr and punches may be needed. I proceed to the next step after visualizing and mobilizing the caudal edge of the ligament.
Medial resection of the SAP
I return to the SAP. The guide for partial resection of its medial portion is 3–5 mm from base to tip. I perform it with 3 mm Kerrison punches or an osteotome, limiting the extent to what is required for decompression. I remove loose bone fragments and the lateral portion of the ligamentum flavum under direct endoscopic visualization.
Hemostasis within the spinal canal
I control bleeding from epidural vessels by targeted coagulation with a 5 mm or 1.5 mm RF electrode under direct endoscopic visualization with continuous irrigation and free outflow. In my practice, near the dura mater or a nerve root, I use COAG 2 on the BONSS ARS600 generator; this is a scale level, not power in watts. I do not activate ABLATE mode near neural structures.
I orient the back of the electrode toward neural structures; its active surface must contact only the tissue to be coagulated. I use a separate inactive instrument to protect and gently retract neural structures. I do not coagulate toward the nerve because of the risk of thermal injury.
Mobilization of neural structures
In lateral recess stenosis, the nerve root may be adherent to ventral structures of the spinal canal. If needed after ligamentum flavum removal, I perform gentle mechanical adhesiolysis with an elevator only to the extent required for safe mobilization and decompression.
I perform adhesiolysis only when the lateral margin of the nerve root is clearly visible. I rest the elevator on the posterior surface of the vertebral body or disc and mobilize the nerve root medially with gentle gliding movements. I avoid forceful displacement and excessive traction.
If a disc component contributes to compression, I remove it using the technique described in the chapters on intracanal disc herniations.
Wound drainage
Before wound closure, I recheck hemostasis with the hydrostatic tamponade effect of irrigation reduced. A drain does not replace meticulous hemostasis.
In my practice, after lumbar BESS/UBE decompression, I place a No. 15 drain tube. I place it in the operative cavity created and bring it out through the working portal or a separate stab incision. I secure it to the skin with Vicryl 2-0 suture and connect it to a drainage system with a 300 or 500 mL reservoir.
I remove the drain the next day. If there are signs of drain-related irritation of neural structures, I remove it immediately. Irritation may result both from contact with the tube and from negative pressure generated by the drainage system.
If new or increasing pain develops, I assess neurological status. Increasing pain, weakness, or bladder or bowel dysfunction require urgent exclusion of a compressive hematoma. Removing the drain does not replace this assessment and the necessary treatment.
Sutures
I place an interrupted Vicryl 2-0 skin suture at each portal. I do not routinely place subcutaneous sutures.
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. Heo DH, Park DY, Hong YH, Kim D, Kim JS. Temperature change of epidural space by radiofrequency use in biportal endoscopic lumbar surgery: safety evaluation of radiofrequency. Eur Spine J. 2023;32(8):2769–2775. DOI: 10.1007/s00586-023-07719-z.
4. Ahn DK, Lee JS, Shin WS, Kim S, Jung J. Postoperative spinal epidural hematoma in a biportal endoscopic spine surgery. Medicine (Baltimore). 2021;100(6):e24685. DOI: 10.1097/MD.0000000000024685.
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