To begin, position the patient in a prone position on a radiolucent operating table and appropriately flex the patient. Identify the specific lumbar segment responsible for the clinical symptoms as the target for the surgical procedure. Determine the skin incision site and the point for docking the working channel on the anteroposterior view of fluoroscopy.
Select the lateral edge of the left lumbar four to five interlaminar window as the docking target and identify its vertical projection on the body surface as the entry point for the skin. Create a 10-millimeter stab incision through the skin, reaching deep to the fascia layer. Guided by fluoroscopy, introduce a pencil-like rod, with a two-millimeter diameter, till it touches the left L4 to 5 articular bone.
Using a soft tissue extender, gradually enlarge the opening through the vertebral muscle and fascia. Subsequently, insert a 10-millimeter triangular work sleeve with an oblique opening. Next, take the appropriate endoscopic surgical system and introduce the same through the opening to perform the subsequent steps under continuous irrigation and endoscopic visualization.
Under high-definition endoscopic visualization, dissect the soft tissue from the bone and achieve hemostasis, using the Radio Frequency Pro. Start the ipsilateral bony decompression, commencing at the L4 lamina, utilizing a 3.5 millimeter endoscopic diamond burr, five millimeter trephine, and Kerrison Rongeur, remove the lower section of the L4 lamina and the medial part of the L4 to 5 articular processes. With the trephine, effectively remove the L4 inferior articular process, enclosed by the joint capsule and ligament, remove the upper edge of the L5 lamina.
Using a Rongeur, separate and remove the superficial layer of the ligamentum flavum from the inner layer. Cut the medial edge of the L5 superior articular process to release the lateral border of the ligamentum flavum. Next, proceed with contralateral bony decompression, commencing at the base of the L4 spinous process.
Polish the contralateral lower portion of the L4 lamina from the inner surface, to expose the cephalad margin of the ligamentum flavum. Detach the contralateral lateral margin of the ligamentum flavum from the contralateral L5 superior articular process, using a diamond burr or Kerrison Rongeur or both, remove the medial section of the L5 superior articular process. Upon completing bony decompression and releasing ligamentum flavum attachments, remove the ligamentum flavum either in an En bloc manner or in a piecemeal manner.
Examine both lateral recesses to ensure thorough decompression of bilateral traversing nerves. Using endoscopic radiofrequency bipolar, achieve meticulous hemostasis. Close the skin incision with one or two stitches, each approximately one centimeter in length.
Patients exhibited satisfactory results at the end of the 24-month follow-up period after the lumbar endoscopic unilateral laminotomy for bilateral decompression. There was a significant improvement in the visual analog scores, Japanese Orthopedic Association scores, and Oswestry Disability Index, over time.
