scholarly journals Interbody Spacer Material Properties and Design Conformity for Reducing Subsidence During Lumbar Interbody Fusion

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Lillian S. Chatham ◽  
Vikas V. Patel ◽  
Christopher M. Yakacki ◽  
R. Dana Carpenter
Keyword(s):  
Lumbar Spine ◽  
Interbody Fusion ◽  
Experimental Testing ◽  
Posterior Instrumentation ◽  
Pedicle Screws ◽  
Stress And Strain ◽  
Fe Model ◽  
Lumbar Interbody Fusion ◽  
Cadaveric Specimen ◽  
Vertebral Endplates

There is a need to better understand the effects of intervertebral spacer material and design on the stress distribution in vertebral bodies and endplates to help reduce complications such as subsidence and improve outcomes following lumbar interbody fusion. The main objective of this study was to investigate the effects of spacer material on the stress and strain in the lumbar spine after interbody fusion with posterior instrumentation. A standard spacer was also compared with a custom-fit spacer, which conformed to the vertebral endplates, to determine if a custom fit would reduce stress on the endplates. A finite element (FE) model of the L4–L5 motion segment was developed from computed tomography (CT) images of a cadaveric lumbar spine. An interbody spacer, pedicle screws, and posterior rods were incorporated into the image-based model. The model was loaded in axial compression, and strain and stress were determined in the vertebra, spacer, and rods. Polyetheretherketone (PEEK), titanium, poly(para-phenylene) (PPP), and porous PPP (70% by volume) were used as the spacer material to quantify the effects on stress and strain in the system. Experimental testing of a cadaveric specimen was used to validate the model's results. There were no large differences in stress levels (<3%) at the bone–spacer interfaces and the rods when PEEK was used instead of titanium. Use of the porous PPP spacer produced an 8–15% decrease of stress at the bone–spacer interfaces and posterior rods. The custom-shaped spacer significantly decreased (>37%) the stress at the bone–spacer interfaces for all materials tested. A 28% decrease in stress was found in the posterior rods with the custom spacer. Of all the spacer materials tested with the custom spacer design, 70% porous PPP resulted in the lowest stress at the bone–spacer interfaces. The results show the potential for more compliant materials to reduce stress on the vertebral endplates postsurgery. The custom spacer provided a greater contact area between the spacer and bone, which distributed the stress more evenly, highlighting a possible strategy to decrease the risk of subsidence.

scholarly journals Lateral Lumbar Interbody Fusion for Ossification of the Yellow Ligament in the Lumbar Spine: First Reported Case

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Kengo Fujii ◽  
Tetsuya Abe ◽  
Toru Funayama ◽  
Hiroshi Noguchi ◽  
Keita Nakayama ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Interbody Fusion ◽  
Pedicle Screws ◽  
Lateral Wall ◽  
Posterior Longitudinal Ligament ◽  
Posterior Fixation ◽  
Lumbar Interbody Fusion ◽  
Venous Plexus ◽  
Lateral Lumbar Interbody Fusion ◽  
Initial Surgery

When ossification of the yellow ligament (OYL) occurs in the lumbar spine and extends to the lateral wall of the spinal canal, facetectomy is required to remove all of the ossified lesion and achieve decompression. Subsequent posterior fixation with interbody fusion will then be necessary to prevent postoperative progression of the ossification and intervertebral instability. The technique of lateral lumbar interbody fusion (LLIF) has recently been introduced. Using this procedure, surgeons can avoid excess blood loss from the extradural venous plexus and detachment of the ossified lesion and the ventral dura mater is avoidable. We present a 55-year-old male patient with OYL at L3/4 and anterior spondylolisthesis of L4 vertebra, with concomitant ossification of the posterior longitudinal ligament, who presented with a severe gait disturbance. He underwent a 2-stage operation without complications: LLIF for L3/4 and L4/5 was performed at the initial surgery, and posterior decompression fixation using pedicle screws from L3 to L5 was performed at the second surgery. His postoperative progress was favorable, and his interbody fusion was deemed successful. Here, we present the first reported case of LLIF for OYL of the lumbar spine. This procedure can be a good option for OYL of the lumbar spine.

Assessment of L5–S1 anterior lumbar interbody fusion stability in the setting of lengthening posterior instrumentation constructs: a cadaveric biomechanical study

2021 ◽  
pp. 1-9
Keyword(s):  
Interbody Fusion ◽  
Posterior Instrumentation ◽  
Pedicle Screws ◽  
Axial Rotation ◽  
Anterior Lumbar Interbody Fusion ◽  
Posterior Fusion ◽  
Lumbar Interbody Fusion ◽  
Lateral Bending ◽  
Fusion Construct ◽  
Flexion Extension

OBJECTIVE Excessive stress and motion at the L5–S1 level can lead to degenerative changes, especially in patients with posterior instrumentation suprajacent to L5. Attention has turned to utilization of L5–S1 anterior lumbar interbody fusion (ALIF) to stabilize the lumbosacral junction. However, questions remain regarding the effectiveness of stand-alone ALIF in the setting of prior posterior instrumented fusions terminating at L5. The purpose of this study was to assess the biomechanical stability of an L5–S1 ALIF with increasing lengths of posterior thoracolumbar constructs. METHODS Seven human cadaveric spines (T9–sacrum) were instrumented with pedicle screws from T10 to L5 and mounted to a 6 degrees-of-freedom robot. Posterior fusion construct lengths (T10–L5, T12–L5, L2–5, and L4–5) were instrumented to each specimen, and torque-fusion level relationships were determined for each construct in flexion-extension, axial rotation, and lateral bending. A stand-alone L5–S1 ALIF was then instrumented, and L5–S1 motion was measured as increasing pure moments (2 to 12 Nm) were applied. Motion reduction was calculated by comparing L5–S1 motion across the ALIF and non-ALIF states. RESULTS The average motion at L5–S1 in axial rotation, flexion-extension, and lateral bending was assessed for each fusion construct with and without ALIF. After adding ALIF to a posterior fusion, L5–S1 motion was significantly reduced relative to the non-ALIF state in all but one fused surgical condition (p < 0.05). Longer fusions with ALIF produced larger L5–S1 motions, and in some cases resulted in motions higher than native state motion. CONCLUSIONS Posterior fusion constructs up to L4–5 could be appropriately stabilized by a stand-alone L5–S1 ALIF when using a nominal threshold of 80% reduction in native motion as a potential positive indicator of fusion. The results of this study allow conclusions to be drawn from a biomechanical standpoint; however, the clinical implications of these data are not well defined. These findings, when taken in appropriate clinical context, can be used to better guide clinicians seeking to treat L5–S1 pathology in patients with prior posterior thoracolumbar constructs.

scholarly journals Single Position Lateral Lumbar Fusion Utilizing Robot Guided Screw Placement

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
George V Huffmon
Keyword(s):  
Pedicle Screw ◽  
Interbody Fusion ◽  
Structural Integrity ◽  
Lumbar Fusion ◽  
Posterior Instrumentation ◽  
Pedicle Screws ◽  
Lateral Position ◽  
Screw Placement ◽  
Lumbar Interbody Fusion ◽  
Pedicle Screw Placement

Abstract INTRODUCTION Lateral position interbody lumbar fusion surgery has become popular as an excellent modality for obtaining lumbar fusion and achieving sagital balance. Posterior instrumentation with pedicle screw fixation adds structural integrity to the construct. Maintaining the patient in the lateral position for pedicle screw placement decreases the time that the patient is under general anesthesia. Since August 2017 we have successfully performed 32 single position pedicle screw fixations utilizing robotic guidance. METHODS The lateral position was utilized for interbody fusion using a variety of techniques; oblique lumbar interbody fusion, extreme lateral lumbar interbody fusion, and lateral anterior lumbar interbody fusion. The Mazor X robot (Medtronic) was utilized for guidewire placement maintaining the patient in the lateral position. Pedicle screws of various manufacturers were placed over the guide wires and connecting rods were placed in the lateral position. RESULTS Since August 2017 we have successfully placed pedicle screws in 1 and 2 level single position lateral lumbar fusions in 32 of 39 cases attempted. There were no nerve root injuries nor any complications related to pedicle screw placement. CONCLUSION Single position lateral lumbar fusion cases utilizing robotic guidance for pedicle screw placement is a viable surgical procedure. Placement of the pedicle screws in the lateral position can reduce intraoperative anesthetic time by eliminating the placement of the patient into the prone position. Utilization of robotic guidance can decrease intraoperative fluoroscopy exposure.

scholarly journals Biomechanical analysis of an expandable lateral cage and a static transforaminal lumbar interbody fusion cage with posterior instrumentation in an in vitro spondylolisthesis model

2016 ◽  
Vol 24 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Matthew Mantell ◽  
Mathew Cyriac ◽  
Colin M. Haines ◽  
Manasa Gudipally ◽  
Joseph R. O’Brien
Keyword(s):  
Interbody Fusion ◽  
Facet Joint ◽  
Posterior Instrumentation ◽  
Degenerative Spondylolisthesis ◽  
Pedicle Screws ◽  
Transforaminal Lumbar Interbody Fusion ◽  
Biomechanical Analysis ◽  
Lumbar Interbody Fusion ◽  
Significant Difference ◽  
Flexion Extension

OBJECT Insufficient biomechanical data exist from comparisons of the stability of expandable lateral cages with that of static transforaminal lumbar interbody fusion (TLIF) cages. The purpose of this biomechanical study was to compare the relative rigidity of L4–5 expandable lateral interbody constructs with or without additive pedicle screw fixation with that of L4–5 static TLIF cages in a novel cadaveric spondylolisthesis model. METHODS Eight human cadaver spines were used in this study. A spondylolisthesis model was created at the L4–5 level by creating 2 injuries. First, in each cadaver, a nucleotomy from 2 channels through the anterior side was created. Second, the cartilage of the facet joint was burred down to create a gap of 4 mm. Light-emitting-diode tracking markers were placed at L-3, L-4, L-5, and S-1. Specimens were tested in the following scenarios: intact model, bilateral pedicle screws, expandable lateral 18-mm-wide cage (alone, with unilateral pedicle screws [UPSs], and with bilateral pedicle screws [BPSs]), expandable lateral 22-mm-wide cage (alone, with UPSs, and with BPSs), and TLIF (alone, with UPSs, and with BPSs). Four of the spines were tested with the expandable lateral cages (18-mm cage followed by the 22-mm cage), and 4 of the spines were tested with the TLIF construct. All these constructs were tested in flexion-extension, axial rotation, and lateral bending. RESULTS The TLIF-alone construct was significantly less stable than the 18- and 22-mm-wide lateral lumbar interbody fusion (LLIF) constructs and the TLIF constructs with either UPSs or BPSs. The LLIF constructs alone were significantly less stable than the TLIF construct with BPSs. However, there was no significant difference between the 18-mm LLIF construct with UPSs and the TLIF construct with BPSs in any of the loading modes. CONCLUSIONS Expandable lateral cages with UPSs provide stability equivalent to that of a TLIF construct with BPSs in a degenerative spondylolisthesis model.

scholarly journals A Technical Nuance to Avoid Lumbar Five Radiculopathy with Anterior Lumbar Fusion and Posterior Instrumentation

2021 ◽  
Vol 2021 ◽  
pp. 1-4
Author(s):  
Matthew T. Neal ◽  
Maziyar A. Kalani ◽  
Mark K. Lyons
Keyword(s):  
Spinal Canal ◽  
Interbody Fusion ◽  
Lumbar Fusion ◽  
Posterior Instrumentation ◽  
Pedicle Screws ◽  
Anterior Lumbar Interbody Fusion ◽  
Foraminal Stenosis ◽  
Lumbar Interbody Fusion ◽  
Exact Position ◽  
Foraminal Height

The anterior lumbar interbody fusion (ALIF) is a well-established procedure used to treat a multitude of spinal pathologies. When performed at the L5-S1 level, the ALIF is often supplemented with posterior pedicle screw and rod fixation. Because the interbody device can restore disk and foraminal height, one benefit of the ALIF procedure is indirect neural decompression in the spinal canal and neural foramina. If the contour of the posterior rod is not matched to the exact position of the tulip heads on the pedicle screws, spondylolisthesis can be introduced, leading to foraminal stenosis and nerve compression. This concern is particularly germane when the posterior instrumentation is placed percutaneously without any direct foraminal decompression. In this report, we describe a patient who had an L4-S1 ALIF, resulting in new L5-S1 retrolisthesis and worsening L5 radiculopathy. Technical nuances and avoidance strategies are discussed.

scholarly journals Expert Consensus on Clinical Application of Lateral Lumbar Interbody Fusion: Results From a Modified Delphi Study

2021 ◽  
pp. 219256822110126
Author(s):  
Yong Hai ◽  
Jingwei Liu ◽  
Yuzeng Liu ◽  
Tie Liu ◽  
Xinuo Zhang ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Delphi Method ◽  
Delphi Study ◽  
Interbody Fusion ◽  
Expert Consensus ◽  
Lumbar Spine Surgery ◽  
Study Group ◽  
Lumbar Interbody Fusion ◽  
Modified Delphi ◽  
Chinese Study

Study Design: Modified Delphi study. Objective: The objective of this study was to establish expert consensus on the application of lateral lumbar interbody fusion (LLIF) by using the modified Delphi study. Methods: From June 2019 to March 2020, Members of the Chinese Study Group for Lateral Lumbar Spine Surgery were selected to collect expert feedback using the modified Delphi method where 65 spine surgeons from all over China agreed to participate. Four rounds were performed: 1 face-to-face meeting and 3 subsequent survey rounds. The consensus was achieved with ≥a 70.0% agreement for each question. The recommendation of grade A was defined as ≥90.0% of the agreement for each question. The recommendation of grade B was defined as 80.0-89.9% of the agreement for each question. The recommendation of grade C was defined as 70.0-79.9% of the agreement for each question. Results: A total of 65 experts formed a panelist group, and the number of questionnaires collected was 63, 59, and 62 in the 3 rounds. In total, 5 sections, 71 questions, and 382 items achieved consensus after the Delphi rounds including summary; preoperative evaluation; application at the lumbar spinal stenosis, lumbar disc herniation, lumbar spondylolisthesis, adult degenerative scoliosis, postoperative adjacent segmental degeneration, and revision surgery; complications; and postoperative follow-up evaluation of LLIF. Conclusion: The modified Delphi method was utilized to ascertain an expert consensus from the Chinese Study Group for Lateral Lumbar Spine Surgery to inform clinical decision-making in the application of LLIF. The salient grade A recommendations of the survey are enumerated.

Outcomes of 2-level posterior lumbar interbody fusion for 2-level degenerative lumbar spondylolisthesis

2013 ◽  
Vol 19 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Hironobu Sakaura ◽  
Tomoya Yamashita ◽  
Toshitada Miwa ◽  
Kenji Ohzono ◽  
Tetsuo Ohwada
Keyword(s):  
Lumbar Spine ◽  
Clinical Outcome ◽  
Interbody Fusion ◽  
Sagittal Alignment ◽  
Posterior Lumbar Interbody Fusion ◽  
Adjacent Segment ◽  
Lumbar Interbody Fusion ◽  
Single Level ◽  
The Mean

Object A systematic review concerning surgical management of lumbar degenerative spondylolisthesis (DS) showed that a satisfactory clinical outcome was significantly more likely with adjunctive spinal fusion than with decompression alone. However, the role of adjunctive fusion and the optimal type of fusion remain controversial. Therefore, operative management for multilevel DS raises more complicated issues. The purpose of this retrospective study was to elucidate clinical and radiological outcomes after 2-level PLIF for 2-level DS with the least bias in determination of operative procedure. Methods Since 2005, all patients surgically treated for lumbar DS at the authors' hospital have been treated using posterior lumbar interbody fusion (PLIF) with pedicle screws, irrespective of severity of slippage, patient age, or bone quality. The authors conducted a retrospective review of 20 consecutive cases involving patients who underwent 2-level PLIF for 2-level DS and had been followed up for 2 years or longer (2-level PLIF group). They also analyzed data from 92 consecutive cases involving patients who underwent single-level PLIF for single-level DS during the same time period and had been followed for at least 2 years (1-level PLIF group). This second group served as a control. Clinical status was assessed using the Japanese Orthopaedic Association (JOA) score. Fusion status and sagittal alignment of the lumbar spine were assessed by comparing serial plain radiographs. Surgery-related complications and the need for additional surgery were evaluated. Results The mean JOA score improved significantly from 12.8 points before surgery to 20.4 points at the latest follow-up in the 2-level PLIF group (mean recovery rate 51.8%), and from 14.2 points preoperatively to 22.5 points at the latest follow-up in the single-level PLIF group (mean recovery rate 55.3%). At the final follow-up, 95.0% of patients in the 2-level PLIF group and 96.7% of those in the 1-level PLIF group had achieved solid spinal fusion, and the mean sagittal alignment of the lumbar spine was more lordotic than before surgery in both groups. Early surgery-related complications, including transient neurological complications, occurred in 6 patients in the 2-level PLIF group (30.0%) and 11 patients in the 1-level PLIF group (12.0%). Symptomatic adjacent-segment disease was found in 4 patients in the 2-level PLIF group (20.0%) and 10 patients in the 1-level PLIF group (10.9%). Conclusions The clinical outcome of 2-level PLIF for 2-level lumbar DS was satisfactory, although surgery-related complications including symptomatic adjacent-segment disease were not negligible.

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