Direct Lateral Endoscopic Lumbar Interbody Fusion and Instrumentation

24 Direct Lateral Endoscopic Lumbar Interbody Fusion and Instrumentation

Jin-Sung Luke Kim and Choon Keun Park

24.1 Introduction

Lumbar interbody fusion (LIF) methods, such as posterior lumbar interbody fusion (PLIF),1,2,3 transforaminal lumbar interbody fusion (TLIF),^4,5,6 anterior lumbar interbody fusion (ALIF),^7,8 and axial lumbar interbody fusion (axial LIF),⁹ have been effective surgical treatment for degenerative lumbar spondylosis with instability and persistent chronic pain. Since Pimenta first introduced the retroperitoneal transpsoas minimally invasive lateral LIF in 2006,¹⁰ cases of lateral lumbar interbody fusion (LLIF) have been increasing for spine surgeons. LLIF has strong advantages, such as cortex-to-cortex wide interbody graft, less tissue damage, preservation of posterior ligaments and muscles, minimal blood loss, short operation time, and early return to work. For these reasons, many surgeons prefer LLIF, especially in elderly and debilitated patients.

24.2 Choice of Patient

Indications for the procedure are:

• Degenerative disk disease with instability

• Recurrent disk herniation

• Postlaminectomy syndrome

• Adjacent segment pathology requiring additional surgery (problems at a level adjacent to a previous fusion surgery)

• Degenerative/isthmic spondylolisthesis

• Degenerative scoliosis (right/left curvature of the spine)

• Posterior pseudarthrosis (previous fusion surgery that did not fuse)

Contraindications to LLIF are:

• Symptomatic level at L5–S1

• Symptomatic level at L4–L5 with high iliac crest

• Lumbar deformities with more than 30° of rotation

• Degenerative spondylolisthesis greater than Grade 2

• Retroperitoneal scarring on both left and right sides (e.g., due to abscess or prior surgery)

• Need for direct decompression through the same approach.

24.3 Surgical Technique

The procedure is performed with the patient under general anesthesia and in the lateral decubitus position (Fig. 24.1). The intervertebral disk and margins of vertebrae are marked under C-arm fluoroscopic guidance. The surgeon can be positioned in front or in back of the patient. A skin incision of about 2 to 2.5 cm is made, and serial dissection of the external oblique, internal oblique, and transversalis abdominis muscles is performed using the muscle-splitting technique (Video 24.1). Then, the retroperitoneal space is exposed. The surgeon identifies the psoas muscle using the index finger, and a guide pin is inserted at the disk space under fluoroscopic guidance with neuromonitoring. Serial dilators are sequentially applied and a 22-mm diameter tubular retractor is attached to the table using a flexible arm (Fig. 24.2).

Fig. 24.1 Position for direct lateral interbody fusion (DLIF).

Fig. 24.2 Tubular retractor and flexible arm mounted on operating table.

The intervertebral disk is removed and the end plate is prepared using curets, a shaver, and long pituitary forceps by the usual methods under C-arm fluoroscopic guidance. Finally, a large lordotic cage (6 or 12°) is carefully placed through the direct lateral interbody fusion (DLIF) corridor at the affected level as an interbody device containing allograft bone chips mixed with demineralized bone matrix (DBM; Video 24.2). In the case of moderate to severe osteoporosis, cancellous bone can be harvested from the iliac bone. The wound is closed layer by layer after removal of the retractor systems. After changing the patient to the prone position, additional posterior fixation is performed using percutaneous pedicle screws (Fig. 24.3).

The patient is allowed to recover from anesthesia and may be discharged in as little as two to three days. The patient is supplied with an opioid analgesic, nonsteroidal anti-inflammatory drug, and muscle relaxant.