9.3. Surgical Approach
@ProfFishchenkoIn my practice, I position the patient prone on a Wilson frame to provide lumbar flexion. This enlarges the interspinous space and facilitates access through an interlaminar window narrowed by degenerative facet joint changes. We coordinate head and trunk positioning with the anesthesiologist to maintain ventilation and venous outflow. We keep the head neutral and avoid pressure on the eyes and abdomen.
The anesthesiologist determines the target blood pressure individually, considering baseline pressure, comorbidities, and organ perfusion. In my practice, a systolic pressure of approximately 100 mmHg may serve as a reference when clinically appropriate. We place soft pads beneath the knees and lower legs.
Before making the incision, we confirm the operative level using the C-arm and correlate vertebral numbering with the preoperative images. We obtain an anteroposterior image. We use a lateral view whenever there is doubt about the level or instrument depth, particularly in lumbarization, sacralization, or hyperlordosis. If necessary, we repeat the lateral check while placing the trocar and dilators.
Left-Sided Approach
The radiographic landmark is the interlaminar space at the appropriate level. We mark the projection of the intervertebral disc on the skin. We plan the proximal endoscopic portal 1–2 cm lateral to the midline, at the level of the midpoint of the cranial vertebra's spinous process. We position the distal working portal 2–3 cm caudally.
Endoscopic Portal
Using a pointed scalpel, we incise the skin, subcutaneous fat, and the outer fascial layer of the longissimus muscle. We insert the first and second dilators until they contact the vertebral lamina. Using the dilators or dedicated muscle dissectors, we separate the muscles from the lamina. By palpation, we identify the lamina, inferior articular process, and the slope toward the interlaminar space. We check the bony landmarks without entering the interlaminar window. We remove the dilators and introduce a trocar into the created portal tract. We again confirm contact with bone and the direction of the slope toward the interlaminar space.
Working Portal
Using a pointed scalpel, we incise the skin, subcutaneous fat, and the outer layer of the thoracolumbar fascia (fascia thoracolumbalis). We rotate the scalpel 90° and make an additional transverse fascial incision. We incise the fascia in a cruciate pattern to improve fluid outflow. We sequentially insert three dilators, palpate the bone, and bring the dilators together with the trocar in the endoscopic portal. We confirm metal-to-metal contact.
We replace the trocar stylet with the scope and camera. We replace the dilators with an RF electrode with a 5 mm working tip and confirm its position under endoscopic video guidance. The meeting point is the lamina of the cranial vertebra.
Using the RF electrode in ablation mode, we expose the laminae of the cranial and caudal vertebrae and the inferior articular process. After identifying the bony landmarks, we remove excess soft tissue over the ligamentum flavum with a 5 mm shaver (Tomcat, Aggressive Plus) or continue ablation with the RF electrode.
At the end of this stage, we clearly visualize:
• the base of the spinous process and lamina of the cranial vertebra;
• the inferior articular process;
• the lamina and base of the spinous process of the caudal vertebra.
References
1. Akbary K, Kim JS, Park CW, Jun SG, Hwang JH. Biportal endoscopic decompression of exiting and traversing nerve roots through a single interlaminar window using a contralateral approach: technical feasibilities and morphometric changes of the lumbar canal and foramen. World Neurosurg. 2018;117:153-161. doi:10.1016/j.wneu.2018.05.111.
2. Tian D, Zhu B, Liu J, Chen L, Sun Y, Zhong H, et al. Contralateral inclinatory approach for decompression of the lateral recess and same-level foraminal lesions using unilateral biportal endoscopy: a technical report. Front Surg. 2022;9:959390. doi:10.3389/fsurg.2022.959390.
3. 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.
4. American Society of Anesthesiologists Task Force on Perioperative Visual Loss, North American Neuro-Ophthalmology Society, Society for Neuroscience in Anesthesiology and Critical Care. Practice advisory for perioperative visual loss associated with spine surgery 2019. Anesthesiology. 2019;130(1):12-30. doi:10.1097/ALN.0000000000002503.
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