L4-5 Interbody Fusion Research Articles

Analyzing the L4-5 Segmental Alignment Change of Two Minimally Invasive Prone-Based Interbody Fusions.

Retrospective Cohort Study. Restoration of lumbar lordosis (LL) is a principal objective during spinal fusion procedures, traditionally focusing on achieving an LL within 10° of the pelvic incidence (PI). Recent studies have demonstrated a relatively constant L4-S1 alignment of 35-40° at L4-S1 and at least 15° at L4-5, regardless of PI. Based on these results, this study was created to examine the success rate of achieving a minimum of 15° at L4-5 through two differing prone-based techniques: Prone Lateral (pLLIF) and Trans Foraminal Interbody Fusion (TLIF). One hundred patients with a primary single-level L4-5 interbody fusion (50 pLLIF and 50 TLIF) were retrospectively analyzed. Pre and post-operative radiographs were measured to examine the segmental change at each level in the lumbar spine and calculate the success rate for achieving a minimum L4-5 segmental lordosis of 15° at the final follow-up. The overall success rate of achieving an L4-5 segmental alignment >15° at the final follow-up was 70%. Prone LLIF was significantly more likely than TLIF to achieve this goal, achieving L4-5 > 15° 84% of the time vs TLIFs 56% (P = 0.002). Prone LLIF demonstrated an average L4-5 increase of 5.6 ± 5.9° which was larger than the mean increase for TLIF 0.4 ± 3.8° (P < 0.001). In both techniques, there was an inverse correlation between pre-operative L4-5 angle and L4-5 angle change. Prone lateral lumbar interbody fusion demonstrates a high success rate for achieving a post-operative L4-5 angle >15° and achieves this at a higher rate than TLIF.

Prone Transpsoas Technique for Simultaneous Single-Position Access to the Anterior and Posterior Lumbar Spine.

Effective decompression, arthrodesis, and correction of spinal conditions frequently utilize operative approaches that expose both the anterior and posterior spinal column. Until now, circumferential spinal column access often requires the surgeon to reposition and drape the patient multiple times or utilize a posterior only approach that has limited anterior correction capability or to utilize a lateral-only approach that complicates otherwise traditional posterior surgical maneuvers. To describe a technique utilizing a single surgical position that enables minimally disruptive anterior column correction with simultaneous access to the posterior spinal column. The operative technique for accessing the lateral lumbar interbody space from a prone transpsoas (PTP) approach is described. The rationale for this approach and a representative case example are reviewed. The PTP approach was used to perform an L3-4 and L4-5 interbody fusion in a 71-yr-old female with spondylolisthesis, severe stenosis, and locked facets. The PTP approach enabled efficient completion of an anterior column correction, direct posterior decompression, multi-segment pedicle fixation, and maintenance of alignment, all while in a single prone position. There were no intraoperative or postoperative complications. The authors' early experience with the described PTP technique suggests it is not only feasible but offers some advantages, as it allows for single-position surgery maximizing both anterior and posterior column access and corrective techniques. Further follow-up studies of this technique are ongoing.

Resolution of screw radiolucency following instrumentation with a hybrid rigid to dynamic stabilization system

Abstract Introduction Screw loosening, a common complication of patients undergoing a semi-rigid fixation, is associated with the radiological finding of lucency within bone surrounding the implanted screw. Case report A clinical and radiologic review is presented of a patient who underwent rigid fixation with L4-5 interbody fusion and L3-4 posterolateral dynamic stabilization with Zimmer Dynamic-to-Optima (DTO) hybrid fusion to non-fusion system (Zimmer Spine, Minneapolis, MN) with hydroxyapatite coated pedicle screws that exhibited lucency on radiographic studies which subsequently disappeared. An L4-5 interbody fusion and L3-4 posterolateral dynamic stabilization was performed. The patient did well clinically postoperatively. At 4 months postoperatively, X-rays of the lumbar spine demonstrated the appearance of lucency around the left L3 pedicle screw, which began to resolve at 10 months, and continued to resolve on subsequent CT scan 1 year postoperatively. The patient's clinical status continued to improve, with no complications. Conclusions The development of radiolucent lines around pedicle screws several months postoperatively may be due to loosening of the screws or due to a stress response at the bone-screw interface. The subsequent disappearance of this finding would suggest the ongrowth of bone at the osteoconductive hydroxyapatite coating or the protection of the bone-screw interface afforded by dynamic stabilization.

An Innovative Use of Cortoss Bone Cement to Stabilize a Nonunion after Interbody Fusion.

A 65-year-old male originally had surgery for spondylolisthesis at L5-S1 in 2008 and then went on to have an L4-5 transforaminal lumbar interbody fusion (TLIF) with pedicle screw fixation from L4 to S1 and interbody graft in 2010. Despite having two surgical procedures, he continued with intractable back pain and was told he had a failed lumbar fusion. When he was evaluated with a computerized tomography (CT) scan from April 2015, it demonstrated an erosive nonunion of the L4-5 interbody fusion without incorporation of the polyetheretherketone (PEEK) cage. In an attempt to perform a minimally invasive stabilization of the L4-5 nonunion, he underwent a percutaneous lateral foraminal approach with an injection of Cortoss® cement (Stryker®, Malvern, PA) into the L4-5 interspace and around the graft. The objective was to stabilize the nonunion, resulting in intermediate relief of pain.

Experimental study of laparoscopical lumbar interbody fusion with polyporus composite phosphate calcium and rhBMP-2 compounds in sheep

To study the efficacy of polyporus composite phosphate calcium and rhBMP-2 compounds with laparoscopical lumbar interbody fusion in sheep. Fourteen uniform-weight adult sheep were randomly divided into three groups for LA-5 interbody fusion with titanium mesh. Autogenous bone and titanium mesh was applied with open anterior technique in group 1 (n=4). In group 2, 4 sheep were operated with laparoscope technique for LA-5 interbody fusion with composite phosphate calcium (CPC) and titanium mesh. In group 3, 6 sheep underwent laparoscopical L4-5 interbody fusion with titanium mesh as well as polyporus composite phosphate calcium and rhBMP-2 compounds. At Weeks 6 and 12 post-operation, the sheep were sacrificed for imaging, biomechanic and morphological examinations. Although there was no statistical difference between open and laparoscopical interbody fusion group when comparing the remaining disc and endplate decorticated, bone fusion occurred in 3 groups after 3 months. A much larger amount of bony callus was observed earlier in laparoscopical L4-5 interbody fusion group with titanium mesh as well as polyporus composite phosphate calcium and rhBMP-2 compounds than two other groups. Polyporus composite phosphate calcium and rhBMP-2 compounds are suitable prosthetic materials for clinical trials. When these materials are utilized with a laparoscopical technique, satisfactory interbody fusion may be achieved.