Expandable Interbody Device Research Articles

Transforaminal lumbar interbody fusion with an expandable interbody device: Two-year clinical and radiographic outcomes

BackgroundThe use of interbody cages as an adjunct to lumbar spinal fusion remains an important technique to enhance segmental stability, promote solid arthrodesis, maintain neuroforaminal decompression, and preserve/improve segmental lordosis. Appropriate segmental lumbar lordosis and sagittal balance is well-known to be critical for long-term patient outcomes. This study sought to evaluate the radiographic and clinical results of TLIF in patients using an articulating, expandable cage. Primary endpoint was clinical and radiographic outcomes, including complications, at 12 and 24 months. MethodsA total of 37 patients underwent open single-level or 2-level TLIF by a single surgeon using an expandable cage with concomitant bilateral pedicle screws and posterolateral arthrodesis. Clinical outcomes included ODI and VAS for back and legs. Radiographic outcomes included pelvic incidence and tilt, lumbar and segmental lordoses, and disc height at the operative level(s). All outcomes were collected at baseline, 2-weeks, 6-weeks, 3-months, 6-months, 12-months, and 24-months postop. ResultsA total of 28 patients were available for analysis. Nine patients failed to follow-up at 24 months. Mean ODI scores showed significant improvement, from pre-to-postoperative at 24 months (55%; p<.0001). VAS for back and legs was significantly lower at 24 months on average by 72 and 79%, respectively (p<.0001 for both). Both segmental and lumbar lordoses significantly improved by 5.3° and 4.2° (p<.0001 and p=.049), respectively. Average disc height improved by 49% or 6.1 mm (p<.001). No device-related complications nor instances of measured subsidence. One patient had a superficial infection, and another had an intraoperatively repaired incidental durotomy. ConclusionsThe use of an expandable cage contributed to improvement in both segmental and lumbar lordosis with no reported complications at 24-month follow-up. All clinical measures significantly improved as well. The expandable cage design represents an effective and safe option to increase cage size and allow significant segmental lordosis correction.

Device profile of the FlareHawk interbody fusion system, an endplate-conforming multi-planar expandable lumbar interbody fusion cage

ABSTRACT Introduction The FlareHawk Interbody Fusion System is a family of lumbar interbody fusion devices (IBFDs) that include FlareHawk7, FlareHawk9, FlareHawk11, TiHawk7, TiHawk9, and TiHawk11. These IBFDs offer a new line of multi-planar expandable interbody devices designed to provide mechanical stability, promote arthrodesis, and allow for restoration of disc height and lordosis through a minimal insertion profile during standard open and minimally invasive posterior lumbar fusion procedures. The two-piece interbody cage design consists of a PEEK outer shell that expands in width, height, and lordosis with the insertion of a titanium shim. Once expanded, the open architecture design allows for ample graft delivery into the disc space. Areas covered The design and unique features of the FlareHawk family of expandable fusion cages are described. The indications for their use are discussed. Early clinical and radiographic outcome studies using the FlareHawk Interbody Fusion System are reviewed, and properties of competitor products are outlined. Expert opinion The FlareHawk multi-planar expandable interbody fusion cage is unique amongst the many lumbar fusion cages currently on the market. The multi-planar expansion, open architecture, and adaptive geometry set it apart from its competitors.

Expandable vs Static Interbody Devices for Lateral Lumbar Interbody Fusion.

Lateral lumbar interbody fusion (LLIF) has paved a way for minimally invasive surgical treatment of a wide variety of spine pathologies. Interbody devices are used to stabilize painful disc levels, provide indirect decompression of neural elements, correct deformity, restore lordosis, and provide a sound durable fusion. Through the years, new static and expandable interbody devices have been developed in an attempt to improve radiographic and clinical outcomes in lumbar spine surgery. The purpose of this article is to explore the advantages and disadvantages between static and expandable interbody devices when used in LLIF. Specifically, this article addresses the differences in subsidence, indirect decompression, restoration of lumbar lordosis, complications, patient-reported outcomes, and cost between static and expandable interbody devices.

Decompression of Lumbar Central Spinal Canal Stenosis Following Minimally Invasive Transforaminal Lumbar Interbody Fusion.

This was a retrospective clinical series. The objective of this study was to evaluate radiologic changes in central spinal canal dimensions following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with placement of a static or an expandable interbody device. MIS-TLIF is used to treat lumbar degenerative diseases and low-grade spondylolisthesis. MIS-TLIF enables direct and indirect decompression of lumbar spinal stenosis, with patients experiencing relief from radiculopathy and neurogenic claudication. However, the effects of MIS-TLIF on the central spinal canal are not well-characterized. We identified patients who underwent MIS-TLIF for degenerative lumbar spondylolisthesis and concurrent moderate to severe spinal stenosis. We selected patients who had both preoperative and postoperative magnetic resonance imaging (MRI) and upright lateral radiographs of the lumbar spine. Measurements on axial T2-weighted MRI scans include anteroposterior and transverse dimensions of the dural sac and osseous spinal canal. Measurements on radiographs include disk height, neural foraminal height, segmental lordosis, and spondylolisthesis. We made pairwise comparisons between each of the central canal dimensions and lumbar sagittal segmental radiologic outcome measures relative to their corresponding preoperative values. Correlation coefficients were used to quantify the association between changes in lumbar sagittal segmental parameters relative to changes in radiologic outcomes of central canal dimensions. Statistical analysis was performed for "all patients" and further stratified by interbody device subgroups (static and expandable). Fifty-one patients (age 60.4 y, 68.6% female) who underwent MIS-TLIF at 55 levels (65.5% at L4-L5) were included in the analysis. Expandable interbody devices were used in 45/55 (81.8%) levels. Mean duration from surgery to postoperative MRI scan was 16.5 months (SD 11.9). MIS-TLIF was associated with significant improvements in dural sac dimensions (anteroposterior +0.31 cm, transverse +0.38 cm) and osseous spinal canal dimensions (anteroposterior +0.16 cm, transverse +0.32 cm). Sagittal lumbar segmental parameters of disk height (+0.56 cm), neural foraminal height (+0.35 cm), segmental lordosis (+4.26 degrees), and spondylolisthesis (-7.5%) were also improved following MIS-TLIF. We did not find meaningful associations between the changes in central canal dimensions relative to the corresponding changes in any of the sagittal lumbar segmental parameters. Stratified analysis by interbody device type (static and expandable) revealed similar within-group changes as in the overall cohort and minimal between-group differences. MIS-TLIF is associated with radiologic decompression of neural foraminal and central spinal canal stenosis. The mechanism for neural foraminal and central canal decompression is likely driven by a combination of direct and indirect corrective techniques.

Transfacet Minimally Invasive Transforaminal Lumbar Interbody Fusion With an Expandable Interbody Device-Part II: Consecutive Case Series.

Advances in operative techniques and instrumentation technology have evolved to maximize patient outcomes following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). The transfacet MIS-TLIF is a modified approach to the standard MIS-TLIF that leverages a bony working corridor to access the disc space for discectomy and interbody device placement. To evaluate clinical and radiographic results following transfacet MIS-TLIF using an expandable interbody device. We performed a retrospective review of consecutive patients who underwent transfacet MIS-TLIF for degenerative lumbar spondylolisthesis. Patient-reported outcome measures for pain and disability were assessed. Sagittal lumbar segmental parameters and regional lumbopelvic parameters were assessed on upright lateral radiographs obtained preoperatively and during follow-up. A total of 68 patients (61.8% male) underwent transfacet MIS-TLIF at 74 levels. The mean age was 63.4 yr and the mean follow-up 15.2 mo. Patients experienced significant short- and long-term postoperative improvements on the numeric rating scale for low back pain (-2.3/10) and Oswestry Disability Index (-12.0/50). Transfacet MIS-TLIF was associated with an immediate and sustained reduction of spondylolisthesis, and an increase in index-level disc height (+0.71 cm), foraminal height (+0.28 cm), and segmental lordosis (+6.83°). Patients with preoperative hypolordosis (<40°) experienced significant increases in segmental (+9.10°) and overall lumbar lordosis (+8.65°). Pelvic parameters were not significantly changed, regardless of preoperative alignment. Device subsidence was observed in 6/74 (8.1%) levels, and fusion in 50/53 (94.3%) levels after 12 mo. Transfacet MIS-TLIF was associated with clinical improvements and restoration of radiographic sagittal segmental parameters. Regional alignment correction was observed among patients with hypolordosis at baseline.

Outcomes of Expandable Interbody Devices in Lumbar Fusion

This was a systematic review. The objective of this study was to review radiographic, clinical, and surgical outcomes of expandable interbody device implantation following lumbar fusion. Few studies have evaluated postsurgical outcomes of expandable implants following lumbar interbody fusion. A systematic review was performed to identify studies investigating expandable intervertebral body devices in lumbar fusion. Radiographic parameters, fusion assessments, patient-reported outcomes (PROs), complications, and revision data were recorded. A comparison of expandable and static devices was performed using a meta-analysis. Eleven articles were included. Postoperative improvements for each radiographic parameters for expandable versus static device implantation ranged from: lumbar lordosis, +2.0 to +5.0 degrees (expandable) versus +1.0 to +4.4 degrees (static); segmental lordosis, +1.0 to +5.2 degrees (expandable) versus+1.1 to +2.3 degrees (static); disk height, +0.82 to +4.8 mm (expandable) versus +0.26 to +6.9 mm (static); foraminal height, +0.13 to +2.8 mm (expandable) versus and +0.05 to +3.0 mm (static). Fusion rates ranged from 72.1% at 6 months to 100% at terminal follow-up. Preoperative to final follow-up improvement for the various PROs assessed were: Oswestry Disability Index, -15.4 to -56.3 (expandable) versus -13.6 to -26.3 (static); Visual Analog Scale (VAS) Back, -3.2 to -6.0 (expandable) versus -3.1 to -4.1 (static); and VAS Leg, -2.9 to -7.1 (expandable) -3.0 versus -4.8 (static). Static cages had a reported complication rate ranging from 6.0% to 16.1% and a subsidence rate of 6.0%. Expandable cages had a reported complication rate that ranged from 0.0.% to 10.0% and a subsidence rate of 5.5%-10.0%. A meta-analysis demonstrated a statistically significant difference in the PRO Oswestry Disability Index, but not VAS Back, VAS Leg, or radiographic outcomes (disk height or foraminal height). There is no clear evidence for the use of expandable interbody devices over static devices.

Clinical and Short-Term Radiographic Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion With Expandable Lordotic Devices.

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a well-accepted procedure for the treatment of degenerative lumbar disease. However, its ability to restore lumbar lordosis has been limited. Development of expandable lordotic interbody devices has challenged this limitation, furthering the scope of minimally invasive surgery. To evaluate the radiographic and clinical effects of expandable lordotic interbody devices placed through an MIS-TLIF approach. We conducted a retrospective review of 32 1-level and 18 2-level MIS-TLIFs performed using lordotic expandable interbody devices. Lumbar radiographic measurements, Oswestry Disability Index scores (ODI), and Visual Analogue Scale scores (VAS) were obtained at preoperative, 6 wk follow up, and last follow up time points. Last follow up occurred at a mean of 11.5±7.6 mo (mean±SD). At 6-wk follow-up, segmental lordosis, disc height, and foraminal height increased by an average of 3.4°, 6.4 mm, and 4.4 mm, respectively. Only the 2-level group showed a significant increase in lumbar lordosis of 5.8°. No significant changes occurred in sacral slope, pelvic tilt, or pelvic incidence. Average ODI and VAS decreased by -12.0 and -4.5, respectively. Postoperative lumbar lordosis inversely correlated with preoperative lordosis in patients with an initial Pelvic Incidence to Lumbar Lordosis mismatch (PI-LL) of >10°, (r=-0.5, P=.009). When applied across 2-levels, MIS-TLIF using expandable lordotic interbody devices produced a significant increase in lumbar lordosis. Preoperative lumbar lordosis was found to be a predictor of postoperative lumbar lordotic change in patients with sagittal imbalance.

Endoscopic transforaminal lumbar interbody fusion without general anesthesia: technical innovations and outcomes.

Innovations in surgical techniques and technologies have enabled spine surgeons to offer patients less morbid alternatives to traditional spine procedures. This review will explore the development of the endoscopic transforaminal lumbar interbody fusion (TLIF) without general endotracheal anesthesia (GETA) and discuss the technical refinements and innovations learned from experiences with this technique. The Awake TLIF employs several key technological innovations: (I) conscious sedation; (II) endoscopic visualization; (III) an expandable interbody device; (IV) recombinant human bone morphogenetic protein; (V) long-acting local analgesia; and (VI) percutaneous instrumentation. Technical refinements, including premedication for prophylaxis against nausea, vomiting, and epistaxis, were made as a result of early experiences with this technique. Results from the first 100 patients to undergo the Awake TLIF demonstrated durable clinical benefit beyond one year postoperatively. Operating time, blood loss, and hospital length of stay averages well below those generally seen with conventional MIS TLIF. Patients achieved a significant reduction in Oswestry Disability Index from baseline of -12.3 points (P<0.0001). In this initial 100 patient cohort, four conversions to GETA were required and four complications resulted, three of which occurred during the first 50 cases. To date, over 200 Awake TLIF cases and the first three-level procedure have been performed. Endoscopic TLIF without the use of general anesthesia is a novel but promising approach for short-segment lumbar fusion. Continued technical innovations will likely afford greater improvements in outcomes, both in the acute and long-term recovery periods.

Enhanced Recovery After Surgery™ Awake Minimally-Invasive Transforaminal Lumbar Interbody Fusion: 2-Dimensional Operative Video.

This video demonstrates the awake endoscopic minimally-invasive transforaminal lumbar interbody fusion (MIS-TLIF) used in our institution's developing Enhanced Recovery After Surgery program. This technique relies on 6 key components, including (1) conscious sedation, (2) endoscopic visualization, (3) long-acting local anesthesia, (4) an expandable interbody device, (5) osteobiologics, and (6) percutaneous instrumentation. In joining these technologies, this procedure embodies the principles of minimally invasive surgery while achieving excellent clinical outcomes. We have previously described this procedure in detail, as well as its impact at our institution, including significant reductions in operative time, blood loss, postoperative length of stay, and hospital costs. The procedure depicted in this video involves the off-label use of bone morphogenetic protein-2 and the Spineology Optimesh allograft containment device. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The patient gave direct consent for the use of the video footage and associated information from this surgery for the making and publication of this surgical video.

Static Versus Expandable Devices Provide Similar Clinical Outcomes Following Minimally Invasive Transforaminal Lumbar Interbody Fusion.

Few studies have analyzed differences in radiographic parameters and patient-reported outcomes (PROs) between expandable and static interbody devices in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). To evaluate differences in radiographic parameters and PROs following MIS TLIF between static and expandable interbody devices. Patients undergoing primary, single-level MIS TLIF between 2014 and 2017 were retrospectively identified. Radiographic measurements including lumbar lordosis (LL), segmental lordosis (SL), disc height (DH), and foraminal height (FH) were performed on lateral radiographs before and after MIS TLIF with a static or expandable articulating interbody device. Radiographic outcomes and PROs were compared using paired and unpaired Student's t test. Thirty patients received expandable interbody devices and 30 patients received static interbody devices. The expandable device cohort exhibited significantly greater improvement in DH and FH at final follow-up compared with those receiving a static device. Both device cohorts experienced significant improvements in PROs at 6 months post-operatively. MIS TLIF with an expandable interbody device led to a greater increase of DH and FH than with a static interbody device. Patients undergoing MIS TLIF can expect similar improvements in PROs whether receiving a static or an expandable interbody device. Further studies are required to better understand improvements in clinical outcomes afforded by expandable interbody devices.

Wednesday, September 26, 2018 1:00 PM – 2:00 PM What's New in MIS: 36. Static versus expandable interbody devices in minimally invasive transforaminal lumbar interbody fusion: comparison of radiographic and functional outcomes

BACKGROUND CONTEXT Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) has been demonstrated to be effective in the surgical treatment of lumbar degenerative pathologies. Advances in instrumentation, such as the development of expandable interbody devices, have been made in order to improve surgical outcomes and patient satisfaction. Previous studies have investigated surgical outcomes of different interbody devices. However, few have analyzed differences in radiographic and patient reported outcomes (PROs) between expandable and static interbody devices. PURPOSE The purpose of this study is to evaluate differences in radiographic parameters and PROs following single-level MIS TLIF between static and expandable interbody devices. STUDY DESIGN/SETTING Retrospective analysis of a prospectively managed surgical database. PATIENT SAMPLE Sixty patients who underwent a primary, single level MIS TLIF between 2014 and 2017 that had completed at least six months of postoperative follow-up. OUTCOME MEASURES Improvements in lumbar lordosis (LL), segmental lordosis (SL), disc height (DH), and foraminal height (FH), and improvements in ODI, VAS back pain, and VAS leg pain. METHODS Patients who underwent primary, single-level MIS TLIF between 2014 and 2017 were retrospectively identified. Only patients that had completed at least six months of postoperative follow-up were included. Radiographic measurements including LL, SL, DH and FH were performed on lateral radiographs before and after MIS TLIF with a static or expandable articulating interbody device. Patient characteristics were compared using chi-squared analysis and independent t test for categorical and continuous variables, respectively. Radiographic outcomes and PROs were compared using paired and unpaired Student's t test. RESULTS Sixty patients undergoing MIS TLIF were included in this analysis. Thirty patients received expandable interbody devices and 30 patients received static interbody devices. There were no differences in demographics or perioperative characteristics between cohorts. Both static and expandable device cohorts demonstrated significant increases in DH, FH, and LL (p CONCLUSIONS Undergoing MIS TLIF with an expandable interbody device led to a greater increase of DH than with a static interbody device. Patients reported significant improvements in PROs following MIS TLIF in both expandable and static interbody device cohorts. However, no differences in improvement were demonstrated between surgical cohorts. Although use of expandable interbody device led to greater increases in DH, this may not correlate with superior patient outcomes. As such, patients undergoing MIS TLIF can expect similar improvements in PROs, whether receiving a static or expandable interbody device. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Patient Outcomes Following Posterior Lumbar Interbody Fusion for Adjacent Segment Disease Using VariLift® as a Standalone Expandable Interbody Device

Background: Adjacent Segment Disease (ASD) is a notable complication following lumbar fusion surgery. Clinicians use various surgical techniques to correct the progression of spine deterioration and reduce the risk of continued ASD. The aim of this retrospective case series is to describe patient outcomes following posterior lumbar interbody fusion (PLIF) using the VariLift® standalone interbody device (without supplemental fixation) for the treatment of ASD. Methods: Nine consecutive patients who underwent a single-level PLIF for the treatment of ASD were reviewed. Outcome measures included patient demographics, comorbidities, surgical complications, time to fusion, Visual Analog Scales for Pain (VAS), and overall patient reported recovery of symptoms. Nine patients (8 males, 1 female) with a mean age of 62.3 (42 to 72) years underwent a single-level procedure. The standalone VariLift interbody fusion system was used in all 9 sequential patients, regardless of the type of fusion/fixation instrumentation previously used. Surgical technique consisted of discectomy and generous bilateral laminotomies with medial facetectomies preserving midline ligamentous structures. Results: Radiographic ASD was confirmed in all cases. Each patient had a history of a lumbar fusion. Preoperatively, 89% of patients reported 9-10 VAS back pain levels. All patients experienced symptomatic improvement. By 12 months postoperatively, average VAS back pain score was 2, a significant improvement from baseline (p<0.05). Solid interbody fusion without implant failure was observed in all cases with averaged time to fusion at 346 days (min=181 days). Conclusion/level of evidence: Posterior lumbar interbody fusion using the VariLift device to treat symptomatic ASD offers significant clinical success and solid fusion rates without the need for supplemental fixation or extension of previous supplemental fixation. Level of evidence IV. Clinical relevance: This stand-alone fusion device produced high fusion rates and symptomatic improvement in a sample of patients with severe back pain and ASD.