Disc Space Preparation in Transforaminal Lumbar Interbody Fusion: A Comparison of Minimally Invasive and Open Approaches

Abstract

Background Minimally invasive surgical (MIS) approaches to transforaminal lumbar interbody fusion (TLIF) have been developed as an alternative to the open approach. However, concerns remain regarding the adequacy of disc space preparation that can be achieved through a minimally invasive approach to TLIF.Questions/purposes The purpose of this cadaver study is to compare the adequacy of disc space preparation through MIS and open approaches to TLIF. Specifically we sought to compare the two approaches with respect to (1) the time required to perform a discectomy and the number of endplate violations; (2) the percentage of disc removed; and (3) the anatomic location where residual disc would remain after discectomy. Methods Forty lumbar levels (ie, L1-2 to L5-S1 in eight fresh cadaver specimens) were randomly assigned to open and MIS groups. Both surgeons were fellowship-trained spine surgeons proficient in the assigned approach used. Time required for discectomy, endplate violations, and percentage of disc removed by volume and mass were recorded for each level. A digital imaging software program (ImageJ; US National Institutes of Health, Bethesda, MD, USA) was used to measure the percent disc removed by area for the total disc and for each quadrant of the endplate. Results The open approach was associated with a shorter discectomy time (9 versus 12 minutes, p = 0.01) and fewer endplate violations (one versus three, p = 0.04) when compared with an MIS approach, percent disc removed by volume (80% versus 77%, p = 0.41), percent disc removed by mass (77% versus 75%, p = 0.55), and percent total disc removed by area (73% versus 71%, p = 0.63) between the open and MIS approaches, respectively. The posterior contralateral quadrant was associated with the lowest percent of disc removed compared with the other three quadrants in both open and MIS groups (50% and 60%, respectively). Conclusions When performed by a surgeon experienced with MIS TLIF, MIS and open approaches are similar in regard to the adequacy of disc space preparation. The least amount of disc by percentage is removed from the posterior

An in vitro study examining a novel suction curette device for lumbar discectomy compared with standard manual discectomy

“…7,8 The study by Rihn et al had a substantially better endplate preparation rate than the current study, reporting an overall endplate preparation rate of 73% by surface area. 9 Our results were more consistent with those reported by Tatsumi et al, 10 who found a much lower preparation rate of 39.2% that was more consistent with our study. In our study, surgeons were asked to perform what they considered to be a typical discectomy in preparation for a TLIF.…”

“…The current study also confirmed, quantitatively, the difficulty of removal of material from the posterior-contralateral region for a TLIF procedure. This has also been confirmed by Rihn et al, 9 who found that the posterior-contralateral quadrant was the most difficult quadrant of the disc to remove in a unilateral TLIF in both minimally invasive and open approaches. Pumberger et al, in 2 separate cadaveric studies, also found that the posterior-contralateral quadrant was the most difficult disc quadrant to prepare in a unilateral TLIF.…”

In vitro comparison of endplate preparation between four mini-open interbody fusion approaches

“…This ability to insert an adequately large cage or graft and have a large potential fusion mass area is highly dependent upon the amount and quality of discectomy and endplate preparation that is performed [3]. Thus, proper endplate preparation for interbody fusion typically entails thoroughly removing the disc and endplate cartilage, exposing the underlying bleeding cortical bone, while avoiding gross violation of the endplate and surrounding ligamentous structures [4].…”

“…A recent study by Rihn et al [4] found that a minimally invasive approach for transforaminal interbody fusion (TLIF) was similar to an open approach with regards to the adequacy of disc space preparation. However, with endplate preparation (both area and quality of preparation) being such an important factor to successful healing, concerns remain about the adequacy of disc space and endplate preparation possible in a variety of modern minimally invasive approaches.…”

Letter to the Editor: Disc Space Preparation in Transforaminal Lumbar Interbody Fusion: A Comparison of Minimally Invasive and Open Approaches

“…e read the article by Rihn and colleagues [2] with great interest. In the study, the authors randomly assigned 40 lumbar levels (L1-2 to L5-S1) from eight fresh cadaver specimens to open and minimally invasive surgery (MIS) groups using a random number generator.…”