Abstract

Background: The first 3 cases of transpedicular, transdiscal lumbosacral screw fixation in combination with a pedicle screw construct for isthmic spondylolisthesis were published by Abdu in 1994 [1]. Several small case series with similar constructs, some of them with additional transvertebral cages followed between 2001 and 2006 [2-7]. Grob (1996) was the first to present a series of 16 cases, in which direct transpedicular, transdiscal screw fixation of isthmic or degenerative spondylolisthesis without the use of an additional pedicle screw construct was successfully performed at the L4/5 and L5/S1 levels [8]. Zagra (2009) reported on a series of 62 patients operated on with the Grob technique for isthmic spondylolisthesis at the L3 through S1 levels [9]. Grob and Zagra both used additional posterolateral fusion and both had either 1 or 2 screw breakages in their series, but neither author observed pseudarthroses. The screw-related complications in these 2 series included inadvertent anterior cortical penetration, nerve root compression in the foramen and iliac artery compression, all requiring screw removal and repositioning. These complications already hint at the difficulty of safely drilling the transpedicular, transdiscal trajectories under fluoroscopy guidance with optimum screw purchase, but without compromising neural or vascular structures. The newly developed Guided Oblique Lumbar Interbody Fusion (GOLIF) procedure overcomes these problems by means of robotic-assisted navigation [10, 11]. It also expands on the original Grob procedure in 3 important ways: First, it makes minimally invasive, percutaneous screw placement possible. Second, it allows for the combination with intervertebral cage fusion techniques. And third, it doesnt require the presence of spondylolisthesis. These 3 factors greatly enlarge the range of possible indications. A multicenter study was designed to evaluate the safety and the efficacy of the GOLIF construct in clinical application. Method: Multicentric, non-randomized, prospective trial with 40 subjects. Patients between 18 and 80 years of age and an indication for the operative arthrodesis of a single lumbar or lumbosacral motion segment are eligible for inclusion. Exclusion criteria are true spinal deformities, lumbar hyperlordosis > 70 degrees, spondylolisthesis > 2nd degree (Meyerding), fractures, osteopenia or osteoporosis, inflammatory or malignant systemic diseases, status post irradiation, diabetes mellitus. Primary target criteria regarding safety are intra- and perioperative complications as well as the precision of implant positioning. Primary target criterion regarding efficacy is the execution of the procedure as planned preoperatively. A secondary target criterion regarding stability is the stability of the construct or the fusion, respectively, as evaluated on functional side-view plain X-rays at 12 months. Secondary target criteria regarding clinical improvement are the visual analog scale (VAS) for back and leg pain, the Oswestry Disability Index (ODI), the Short Form (SF) - 12 questionnaire and, depending on the indication, the Swiss Spinal Stenosis Questionnaire (SSSQ). This study protocol has been approved by the institutional ethics review board of the Ludwig-Maximilian-University, Munich. Results: Patient recruitment was begun in November 2009 and at the time of abstract submission, 2 patients have been included. We expect that first results regarding safety will be available at the time of presentation. Discussion: This trial will for the first time assess the safety and efficacy of the GOLIF procedure in a prospective fashion in Europe. The results will be an indicator, whether this minimally invasive technique of spinal fixation may become an alternative for pedicle screw-based fixation in the future. References: 1. Abdu WA, Wilber RG, Emery SE (1994) Pedicular transvertebral screw fixation of the lumbosacral spine in spondylolisthesis. A new technique for stabilization. Spine 19:710-715. 2. Chell J, Quinnell RC (2001) Transvertebral pedicle fixation in severe grade spondylolisthesis. Report of three cases. J Neurosurg 95:105-107. 3. Smith JA, Deviren V, Berven S, Kleinstueck F, Bradford DS (2001) Clinical outcome of trans-sacral interbody fusion after partial reduction for high-grade L5-S1 spondylolisthesis. Spine 26:2227-2234. 4. Boachie-Adjei O, Do T, Rawlins BA (2002) Partial lumbosacral kyphosis reduction, decompression, and posterior lumbosacral transfixation in high-grade isthmic spondylolisthesis: clinical and radiographic results in six patients. Spine 27:E161-168. 5. Francois J, Lauweryns P, Fabry G (2005) Treatment of high-grade spondylolisthesis by posterior lumbosacral transfixation with transdiscal screws: surgical technique and preliminary results in four cases. Acta Orthop Belg 71:334-341. 6. Beringer WF, Mobasser JP, Karahalios D, Potts EA (2006) Anterior transvertebral interbody cage with posterior transdiscal pedicle screw instrumentation for high-grade spondylolisthesis. Technical note. Neurosurg Focus 20:E7. 7. Kotil K, Tunckaya T, Bilge T (2006) Reduction of High-grade Spondylolisthesis Using a Transvertebral Surgical Approach in a Child. A Case Report and Review of the Literature. Turkish Neurosurgery 16:197-201. 8. Grob D, Humke T, Dvorak J (1996) Direct pediculo-body fixation in cases of spondylolisthesis with advanced intervertebral disc degeneration. Eur Spine J 5:281-285. 9. Zagra A, Giudici F, Minoia L, Corriero AS, Zagra L (2009) Long-term results of pediculo-body fixation and posterolateral fusion for lumbar spondylolisthesis. Eur Spine J 18 Suppl 1:151-155. 10. Lieberman IH, Togawa D, Kayanja MM, Reinhardt MK, Friedlander A, Knoller N, Benzel EC (2006) Bone-mounted miniature robotic guidance for pedicle screw and translaminar facet screw placement: Part I--Technical development and a test case result. Neurosurgery 59:641-650; discussion 641-650. 11. Sukovich W, Brink-Danan S, Hardenbrook M (2006) Miniature robotic guidance for pedicle screw placement in posterior spinal fusion: early clinical experience with the SpineAssist. Int J Med Robot 2:114-122.