Minimally Invasive Surgical Techniques for Lumbar Decompression

For the PTED group, the surgical procedure (based on the L4–L5 segment of DLS) was performed following methods reported in the literature [18 (link)]. The following steps were performed: (1) part of the superior articular process (SAP) of L5 was removed. A soft pillow was placed under the patients' waist, while the patient was in the lateral decubitus position with their knee and hip flexed. The incision was located 8–12 cm from the midline horizontally and 1–3 cm above the iliac on the side with leg pain. The mixed local anesthetic, which consisted of 30 mL 1:200,000 epinephrine and 20 mL 2% lidocaine, was only used in PTED group. After 5 mL of the mixed anesthetic was inserted into the skin at the entry point, 20 mL was inserted into the trajectory, 15 mL was inserted into the articular process, and 10 mL was inserted into the foramen. Then, 0.8–1.0 cm of skin and the subcutaneous fascia were incised. Drills were used to resect the ventral osteophytes on the SAP. The PTED system (Hoogland Spine Products, Germany) was inserted (Fig. 1). (2) Parts of the ipsilateral ligamentum flavum, perineural scar, and extruded lumbar disc material were completely resected with endoscopic forceps (Fig. 2). (3) The superior endplate of the L5 vertebral body was removed by endoscopic micro punches and a bone knife. Therefore, 270-degree decompression of the traversing nerve root was achieved (Fig. 3). The drainage tube was placed after hemostasis was reached.Fig. 1

Fluoroscopic views. A, B The drill was inserted to resect the LF and the ventral osteophytes on the SAP. C, D The working cannula was placed

Fig. 2

Endoscopic views. A Endoscopic view of the hypertrophic posterior longitudinal ligament, extruded disc material, and perineural scar. B–G After the endoscopic instruments were used to carefully remove the vertebral body, ventral decompression of the traversing nerve root (L5) was completed. H The dura mater was torn

Fig. 3

Illustrations of the 270-degree PTED. A, B Specific pathologic features of LRS-DLS. C, D Final view of the nerve 270-degree decompression status and the restoration of the lateral recess

For the MIS-TLIF group, the surgical procedure was performed in accordance with methods reported in the literature [19 (link)]. After successful general anesthesia with tracheal intubation, the patient was placed in a prone position with chest and hip pads, and the L4–L5 intervertebral space was marked with X-ray fluoroscopy. The skin and subcutaneous fascia were cut; a trans-muscular surgical corridor was created with two micro-laminectomy retractors docking on the facet joint complex. After exposing the bony structure, part of the lamina and inferior articular process of L4 and the upper L5 articular process were removed with the rongeur on the ipsilateral side, and the hypertrophic ligamentum flavum was peeled backward. If MRI showed contralateral lateral recess stenosis, then predecompression was performed on the contralateral side. After decompression on the dorsal side, the nucleus pulposus and endplate cartilage were removed with forceps. An appropriate cage (Medtronic) filled with autograft from laminectomy was placed in the center of the intervertebral space via the Kambin’s triangle area. After adequate hemostasis was achieved, two drainage tubes were placed and removed when the drainage volume was < 50 mL/d.
Postoperatively, patients was treated with oral nonsteroidal anti-inflammatory drugs and antibiotics for 3 days. All patients were encouraged to perform straight leg raising 1 day postoperatively, and moderate off-bed activity with a brace 2–3 days postoperatively. On the third postoperative day, patients were allowed to go home if their lower extremity pain symptoms were effectively relieved with no evidence of infection. The patient demographics and perioperative outcomes were compared. The VAS score, ODI, and modified Macnab criteria were used to evaluate the clinical outcomes [20 (link)].