Biportal Endoscopic Technique for Transforaminal Lumbar Interbody Fusion: Review of Current Research

Abstract

Background: There are many types of minimally invasive lumbar interbody fusion procedures. Among them is the recently introduced biportal endoscopic lumbar interbody fusion surgery. Biportal endoscopic transforaminal lumbar interbody fusion (TLIF) might combine the advantages of minimally invasive TLIF and endoscopic spine approaches. However, clinical evidence in support of biportal endoscopic TLIF remains insufficient.

Methods: A comprehensive review of English-language literature on biportal endoscopic lumbar interbody fusion was performed. Articles on biportal endoscopic TLIF in PubMed, the Cochrane Library, and Web of Science were searched using the terms "unilateral biportal endoscopy," "biportal endoscopic spine surgery," "transforaminal," and "lumbar interbody fusion" as well as their combinations. The clinical and radiological outcomes of biportal endoscopic TLIF were analyzed and are summarized here. The biportal endoscopic lumbar interbody fusion surgical techniques are then described.

Results: There are 3 biportal endoscopic TLIF techniques. In the available literature, the postoperative 1-year outcomes of biportal endoscopic TLIF were comparable to those of posterior lumbar interbody fusion (PLIF) and minimally invasive (MIS)-TLIF. Clinical parameters were significantly improved after biportal endoscopic TLIF. Compared to PLIF or MIS-TLIF, biportal endoscopic-TLIF may have the advantage of a faster recovery. Biportal endoscopic TLIF showed no inferiority in fusion rates compared to PLIF or MIS-TLIF. The postoperative complications were usually minor.

Conclusions: The postoperative 1-year clinical and radiological outcomes of biportal endoscopic TLIF were favorable compared to those of PLIF and MIS-TLIF. However, long-term outcomes should be investigated through prospective, randomized controlled trials in the future.

Clinical relevance: This review article outlines the most current evidence-based medicine with regard to spinal surgery with an aim to introduce a new technique.

Keywords: biportal; endoscopy; fusion; lumbar; transforaminal lumbar interbody fusion.

Figure 1

Overview of the biportal endoscopic approach for lumbar interbody fusion.

Figure 2

Location of the surgical portals for biportal endoscopic transforaminal lumbar interbody fusion using (A) the modified posterolateral approach, (B) the posterolateral approach, and (C) the extraforaminal approach. P(L): The cranial endoscopic portal located above the pedicle in the posterolateral approach. P(R): The caudal working portal located above the pedicle in the posterolateral approach. C: Additional portal for large interbody cage insertion in the modified far-lateral transforaminal approach. D(L): The cranial endoscopic portal located above the intervertebral disc in the modified posterolateral approach. S: Window for pedicle screw insertion in the modified far-lateral transforaminal approach. P+2(L): The cranial endoscopic portal located 2 cm from the outer lateral interpedicular line in the extraforaminal approach. P+2(R): The caudal working portal located 2 cm from the outer lateral interpedicular line in the extraforaminal approach. Q: Assistance portal located at the cross-section of the medial interpedicular line and the intervertebral disc line.

Figure 3

Two surgical corridors for biportal endoscopic transforaminal lumbar interbody fusion: (A) the posterolateral approach and (B) the trans-Kambin approach.

Figure 4

Optimization of the surgical field of view in biportal endoscopic lumbar interbody fusion surgery. Based on this, (A) sufficient contralateral sublaminar decompression, (B) ipsilateral total facetectomy, and (C) endplate preparation are possible.

Figure 5

Biportal endoscopic transforaminal lumbar interbody fusion through a posterolateral approach (Video 1). A 62-year-old female patient complained of bilateral radicular leg pain with back pain. Preoperative x-ray (A) and magnetic resonance imaging (B, C) depicted grade 2 degenerative spondylolisthesis with central stenosis of L4-5. We performed biportal endoscopic transforaminal lumbar interbody fusion at the L4-5 area. Postoperatively, the patient’s radicular pain was significantly improved. Postoperative magnetic resonance imaging and x-ray (D, E, F, G) revealed good reduction of spondylolisthesis and complete decompression of the central canal at L4-5.

Figure 6

Case of modified far-lateral biportal endoscopic transforaminal lumbar interbody fusion. A 64-year-old male patient presented with bilateral leg pain and claudication. Preoperative x-ray showed isthmic spondylolisthesis of L4-5 (A). We performed modified far-lateral biportal endoscopic transforaminal lumbar interbody fusion at the L4-5 area. Two skin incisions over the pedicles were used for the endoscopic portal and the working portal (B, black lines). An additional lateral skin incision was used for cage insertion (B, white line). A large cage was inserted at L4-5 (C, D). After surgery, spondylolisthesis (E) was well resolved on the postoperative magnetic resonance imaging (F). A large cage was inserted at the L4-5 level (E, G). The intraoperative endoscopic image showed the transverse position of a large cage (H).