Lumbar spondylolisthesis is defined as a forward slippage of a lumbar vertebra relative to the next vertebral body and resulting in instability of the segment[1, 2]. The most common types include degenerative and isthmic lumbar spondylolisthesis. Degenerative spondylolisthesis is one of the most common degenerative spinal disorder in the aging population, and often associated with lumbar canal stenosis[3, 4]. And, it is also a frequent cause of low back pain, and it results from a narrowing of the disc space or nerve root canal[2]. Bhalla pointed out that the chief goals of surgical treatment include neurologic decompression and stabilization of the vertebral segments with instrumented fusion[5]. Posterior lumbar interbody fusion (PLIF) is regarded as most common surgery for degenerative lumbar disease such as degenerative spondylolisthesis and lumbar spinal stenosis[6]. Although open surgery can have good effects, it may damage the paraspinal muscles, result in postoperative pain, prolong hospital stays, protract rehabilitation programs and increase the financial burden to patients. Fan et al. reported extensive stripping of muscles, ligament resection, destroy the architecture of the spinal posterior column may result in spinal instability and failed back surgery syndrome (FBSS)[7]. These drawbacks of standard posterior lumbar interbody fusion have prompted the development of less-invasive techniques[8–11]. Furthermore, with the improvements in surgical instruments and the increase in patients’ demands for quality of life, minimally invasive surgery has been accepted by an increasing number of physicians and patients. Kai-Michael et al[12] pointed out that numerous minimally invasive techniques have been applied for spinal surgery since a novel tubular retractor system was introduced by Foley in 1997. In recent years, a variety of less-invasive procedures that can minimally disrupt normal structures without compromising effectiveness have been applied in the field of spinal surgery, such as minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), anterior lumbar interbody fusion (ALIF), extreme lateral lumbar interbody fusion (XLIF) and oblique lumbar interbody fusion (OLIF), each having its own benefits and drawbacks[13, 14].
Harms et al.[15] first reported transforaminal lumbar interbody fusion (TLIF) technique, which can effectively avoid muscle and nerve root traction injury, in 1982. In 2002, Foley[16] reported that the MIS-TLIF technique, which was derived from TLIF and is performed with a tubular retractor, could effectively preserve back muscles and reduce postoperative complications. In recent years, it has been widely used in the treatment of a variety of lumbar degenerative diseases, with satisfactory outcomes obtained[17]. Many studies have shown that advanced MIS-TLIF is associated with less blood loss and a shorter recovery time than conventional open surgery, but laminotomy, facetectomy and flavum dissection are necessary in order to achieve interbody fusion with the use of cages. Meanwhile, this technique still questioned by its limited workspace and the field of vision of this surgical procedure, steep learning curve, and may higher incidence of complications[18].
Recently, the percutaneous endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) technique was reported to address a variety of spinal disorders by using endoscopic and expandable cages through Kambin’s triangle[19, 20]. Endo-TLIF technique was derived from the percutaneous endoscopic lumbar discectomy (PELD) technique and combined endoscopic visualization, expandable cage technology, and interbody fusion technique[21]. As reported, the Endo-TLIF technique can achieve not only bilateral direct decompression, interbody cage insertion and pedicle implantation but also less dissection of normal structures. In other words, the muscle, soft tissue and nerve roots can be significantly protected because of the access to procedures and the direct visualization under endoscopy. In 2020, AO et al.[22] reported that their study showed that, compared with MIS-TLIF, their percutaneous endoscopic transforaminal lumbar interbody fusion technique has advantages of less surgical trauma, less hidden blood loss, less postoperative low-back pain, and faster recovery. Although both their and our techniques share the label of percutaneous endoscopic transforaminal lumbar interbody fusion technique, they differ in several aspects. The difference not only in the methods of screw implantation, working channel system, surgical procedures and details but also in interbody implant cage. In recent years, research on the Endo-TLIF technique has become a hot topic, and among them, a great many spine surgeons put more attention into the clinical application of the technology, which is an important field.
There are a limited number of studies that have evaluated the use of the Endo-TLIF technique for the treatment of lumbar spondylolisthesis and compared early clinical outcomes with those of other minimally invasive lumbar fusion surgeries. So that, surgeons lack references related to percutaneous endoscopic lumbar interbody fusion technique and clinical experience in evaluating preliminary clinical outcomes. Thus, the aims of this study were as follow: (i) demonstrate the surgical procedures, technique, advantages and drawbacks of Endo-TLIF and MIS-TLIF; (ii) evaluate and compare the early clinical efficacies of two minimally invasive techniques for single-segment lumbar spondylolisthesis; (iii) provide spine surgeons and patients with accurate early outcome of Endo-TLIF and MIS-TLIF and relevant theoretical basis for the choice of operation method.