The level of each pedicle is checked using a C-arm image intensifier, and a vertical incision of approximately 1.5 cm is made just lateral to the pedicle (Fig. 1). In this technique, total facetectomy, decompression, and cage insertion are performed through an incision into which a pedicle screw is inserted. To allow for ideal pedicle screw insertion, each pedicle must be tilted and marked in a true view on the C-arm image intensifier.

If partial laminectomy was performed previously, damage to the nerve tissue must be avoided because severe adherence of the scar tissue, bone, and dura exists. Initially, a blunt instrument is used to peel the soft tissue over the facet joint and lamina. Adherent scar tissue does not peel off easily. However, to prevent damaging the nerve tissue, the work must be done above the bone under the guidance of a C-arm image intensifier (Fig. 2A, B). Subsequently, a blunt instrument is used to palpate and confirm the safe area made of bone. Then, the scar tissue is cut using a surgical blade above the bone in the safe area (Figs. 2C, D, and 3A). Furthermore, the superficial scar tissue adhering to the dura is detached from bone, and the margin of the remaining bone is checked. The scar tissue is carefully peeled off from the bone margin to access the epidural space; however, if this is challenging, a little more bone is removed using a burr or Kerrison punch to secure a space (Fig. 3B). When the space leading to the epidural space is confirmed, adhesiolysis is performed to separate the scar tissue and bone carefully (Figs. 2E, 3C). Then, the scar tissue is removed up to the area where facetectomy will be performed to prevent the dura from being torn apart by the scar tissue when removing the inferior articular process (IAP) (Fig. 2F).

The IAP of the upper vertebra is excised using an osteotome to the area where scar tissue dissection was performed, starting from just above the tip of the superior articular process (SAP) of the lower vertebra (Fig. 2F). When the medial margin of SAP is exposed, the dura lateral margin and bone are carefully separated using a blunt-tipped probe. After palpating the lower pedicle using a probe bent at 90°, facetectomy is performed by removing the SAP using an osteotome in the cranial area of the upper margin of the pedicle.

If Kamabin’s triangle is found after facetectomy, a retractor is used to protect the traversing root without damaging the exiting root, and an annulotomy is performed using a blade. The retractor plays a role in securing visibility and protecting the root during disc preparation. After the disc has been sufficiently removed, an endoscope can be used to check whether the bony endplate has been sufficiently exposed. After disc space preparation, the cage is inserted by either inserting two cages or inserting one large cage. Then, the surgery is completed by inserting the pedicle screw and connecting the rod using the percutaneous technique.

If computed tomography (CT) confirms union of the lower segment, the existing screw can be removed. Initially, the C-arm image intensifier is used to check the location of the existing screw, and a 1.5-cm skin incision is made vertically. After checking the pedicle of the upper segment where the new pedicle screw is to be inserted, a 1.5-cm vertical incision is made on the lateral margin or 1 cm lateral to the lateral margin of the pedicle (Fig. 4).

If an endoscope is not utilized in implant removal, the process may be difficult owing to scar tissue formation and a narrow field of view. However, it can be removed relatively easily using an endoscope. The pedicle screw is checked under C-arm guidance, and a vertical incision of approximately 1.5 cm is made on the lateral margin of the screw head. Subsequently, a blunt instrument is used to push out the soft tissue, which is checked using an endoscope. At this time, a shaver is inserted through the same incision to clean up the soft tissue. Then, the scar tissue can be removed under direct observation using a blade or hook-type electrocautery, allowing for screw removal (Fig. 5A). Because the screw hole is directly visible, a bone chip and a new screw can be inserted easily (Fig. 5B). If screw reinsertion is unnecessary, a material such as bone wax is used to plug the screw hole.

BESS-TLIF is performed on the adjacent segment. Given that no scar tissue exists in this area, it is performed in the same manner as other BESS-TLIF. First, the facet joint and resection part of the IAP and lamina are checked using the osteotome based on the tip of the SAP. Then, the SAP is removed, allowing the assessment of the disc space. After disc preparation, the cage is inserted.

For the level where the screw was previously removed, the existing screw hole is checked using an endoscope, a bone chip is placed into the hole, and a screw that is one size larger is then inserted (Fig. 4C). Subsequently, a screw is inserted at the adjacent level using a percutaneous technique, and the rod is connected.

A 42-year-old female patient, who had undergone three surgeries for L4–5 herniated intervertebral disc, underwent surgery at another hospital for the fourth recurrence 6 months before the outpatient visit. The patient complained of pain in the right lower extremity and back that occurred 2 weeks ago. The herniated intervertebral disc at the L4–5 level and the left laminectomy state were confirmed on magnetic resonance imaging (MRI) (Fig. 6A–C). For this, BESS-TLIF was performed (Fig. 6D, E), and the pain on the lower extremity and back improved.

An 83-year-old male patient underwent L4–5 interbody fusion at a different hospital 2 decades ago and presented with pain radiating to the lower extremity and back pain that began 3 months before visiting Daechan Hospital. Lateral plain radiography confirmed L4–5 fusion and instrumentation, along with retrolisthesis of the L3–4 level (Fig. 7A). MRI confirmed retrolisthesis accompanied by central and both foraminal stenoses at the L3–4 level (Fig. 7B). Preoperative CT revealed bone union at the previous interbody fusion site (Fig. 7). Accordingly, the existing screw was removed, and BESS-TLIF was performed at the L3–4 level (Fig. 7D, E), resulting in relief from both axial pain and radiating pain.

The patient was a 73-year-old man who had undergone spine surgery 4 times before visiting Daechan Hospital. The last fusion surgery was performed 4 years ago. He complained of severe back pain and pain radiating to the lower extremities and had difficulty walking >100 m due to intermittent claudication. Preoperative X-ray imaging revealed interbody fusion of L3–4–5 and spondylolisthesis of L5–S1. At the L3–4 level, the pedicle screw was inserted only on one side (Fig. 8A). Preoperative MRI confirmed central and foraminal stenoses on L5–S1 (Fig. 8B). CT confirmed union at the L4–5 level but nonunion at the L2–3 level (Fig. 8C). Accordingly, BESS-TLIF was performed at the L5–S1 level, during which the existing implant was removed through BESS, and instrumentation was extended from L3 to S1 (Fig. 8D, E). Following surgery, the patient’s radiating pain and claudication, with back pain showing improvement 1 month further.