Revision Surgery for Symptomatic Adjacent Segment Disc Degeneration after Initial Anterior Cervical Fusion: Is ROI-C Better than Plate-Cage Construct?

The optimal revision surgical strategy for patients who develop symptomatic adjacent segment disc degeneration (ASD) is controversial. The risks of intraoperative complications, especially the incidence of dysphagia, were relatively high for revision surgeries. This study was aimed at comparing the efficacy of revision surgery using a traditional plate-cage construct and zero-profile anchored spacer (ROI-C) device in treating symptomatic ASD after initial anterior cervical discectomy and fusion (ACDF) surgery. Forty-two patients who developed symptomatic ASD were retrospectively analyzed and classified into two groups (plate-cage group and ROI-C group). The clinical and radiological results were compared. We further evaluated the complication of dysphagia and dysphagia-related risk factors in these patients. The JOA and NDI scores, C2-7 lordotic angle, and intervertebral space height were significantly improved after revision surgery in both groups. The operative time and intraoperative blood loss both significantly decreased in the ROI-C group. The incidence of postoperative dysphagia was much lower in the ROI-C group than in the plate-cage group (18.75% vs. 57.69%; P = 0.01 ). The presence of dysphagia after initial surgery ( P = 0.003 ) and revision surgery type ( P = 0.01 ) was significantly related to the presence of dysphagia after revision surgery. These results indicated that both the plate-cage construct and ROI-C are effective in treating symptomatic ASD. However, compared with the traditional plate-cage construct, ROI-C with less operative time, less blood loss, and lower incidence of dysphagia is more suitable. Furthermore, ROI-C should preferably be used for patients who present with dysphagia after initial cervical surgery. This study will provide clinical guidance for spinal surgeons to choose the zero-profile device in treating specific and complicated cases, which will significantly improve the therapeutic efficacy of symptomatic adjacent segment degeneration.

Lysosome-targeted lipid probes reveal sterol transporters NPC1 and LIMP2 as sphingosine transporters

Lysosomes are central catabolic organelles involved in lipid homeostasis and their dysfunction is associated with pathologies ranging from lysosomal storage disorders to common neurodegenerative diseases. The mechanism of lipid efflux from lysosomes is well understood for cholesterol, while the export of other lipids, particularly sphingosine, is less well studied. To overcome this knowledge gap, we have developed functionalized sphingosine and cholesterol probes that allow us to follow their metabolism, protein interactions as well as their subcellular localization. These probes feature a modified cage group for lysosomal targeting and controlled release of the active lipids with high temporal precision. An additional photo-crosslinkable group allowed for the discovery of lysosomal interactors for both sphingosine and cholesterol. In this way, we found that two lysosomal cholesterol transporters, NPC1 and LIMP-2/SCARB2, also directly bind to sphingosine. In addition, we showed that absence of either protein leads to lysosomal sphingosine accumulation which suggests a sphingosine transport role of both proteins. Furthermore, artificial elevation of lysosomal sphingosine levels impaired cholesterol efflux, consistent with sphingosine and cholesterol sharing a common export mechanism.

Evaluation of the feasibility of acetabular cup pre-determination in revision total hip arthroplasty via X-ray of the bone stock of the anterosuperior acetabulum

Purpose This study was aimed to explore (1) location on AP pelvic X-ray that displayed bone stock in anterosuperior acetabulum; (2) whether X-ray could provide enough evidence to evaluate whether bone stock could provide support for acetabular cup; (3) criteria to determine whether anterosuperior bone stock could provide sufficient support for cup on X-ray. Methods Our study retrospectively collected 43 patients who underwent revision THA for cup loosening from 2014 to 2019. The position of anterosuperior acetabular bone stock was compared between X-ray and CT-based 3-D reconstruction. Seventy-millimeter acetabular cup was implanted simulatively to obtain the contact line between acetabular cup and superolateral remaining bone stock. The contact line length and the angle were measured. Patients were divided into cup group and cage group, and ROC curves of both contact line length and angle were drawn. Results The superolateral part of acetabulum on X-ray could reflect the anterosuperior host bone stock of acetabulum according to the comparison of anteroposterior pelvic X-ray and 3-D reconstruction. Critical point was chosen when we got the highest sensitivity with a 100% specificity in ROC curves. The critical values of contact length and angle were 15.58 mm and 25.5°. Conclusions Surgeons could assess the anterosuperior bone stock of acetabulum by AP pelvic X-ray to decide whether revision could be done merely using cup or need customized cage. Clinically, when contact line length was larger than 16 mm or contact angle was larger than 25.5°, adoption of cup could obtain primary stability in the revision surgery in most cases.

Female Tilapia Strategising Energy Mobilisation Differently For Growth Or Reproduction Depend On Living Environments

This study was conducted to investigate the energy mobilization and ionoregulation pattern of tilapia living recirculating aquaculture system (RAS) and cage culture environments. Three different groups of tilapia were compared as tilapia cultured in RAS (Group I - RAS), tilapia cultured in open water cage (Group II - Cage) and tilapia transferred from cage to RAS (Group III - Compensation) as physiology compromising model. Results revealed that Group II tilapia mobilized glycogen as primarily energy for daily exercise activity and promoted growth, whilst tilapia from Group I and III mobilised lipid to support gonadogenesis and protein reserved for somatogensis. The gills and kidney NKA activities remained relative stable to maintain balance homeostasis with a electrolytes level. As a remark, this study revealed that tilapia re-strategized their energy mobilization pattern in accessing glycogen as easy energy to support exercise metabolism and mobilized lipid and protein for growth and gonadal development.

Preparation of Nano Hydroxyapatite/Polyamide Composite and Its Application in Lumbar Disc Herniation Operation

Carbon fiber (CFR) was used to strengthen the mechanical properties of hydroxyapatite/polyamide (ha/pa) to synthesize ternary composites with different mass fraction. At the same time, its mechanical and material characterization were compared with that of ha/pa without CFR. CFR-ha/pa was used as the substrate for the culture of mouse bone marrow mesenchymal stem cells (C3H10T1/2). The cell morphology and adhesion properties of materials were analyzed by immuno light staining of cytoskeleton and adhesion protein, and FESEM. The interbody fusion cage based on the material was used in the treatment of lumbar disc herniation. According to the X-ray film and the corresponding scoring standards (JOA, ODI and VAS), the therapeutic effect of the interbody fusion cage was evaluated. The results showed that there were cavities on the surface of CFR-ha/pa composites. With the increase of the mass fraction of CFR in CFR-ha/pa composites, the compressive strength (from 115 MPa to 218 Mpa), the bending strength (from 85 MPa to 140 MPa) and other mechanical indexes of the composite increased obviously. After 24 h of cell inoculation, the substrate of CFR-ha/pa group was covered by layered, well spread and fused cells, and there was dense cell adhesion around it, that was to say, the material and cells showed good adhesion performance. At the same time, the levels of Integrin α1 and Integrin β1 significantly increased in CFR-ha/pa group (P < 0.05). The VAS and ODI scores of polyether ether ketone (Peek) interbody fusion cage group and CFR-ha/pa interbody fusion cage group were lower than those before operation (P < 0.05). The therapeutic effect of CFR-ha/pa interbody fusion cage is better than Peek interbody fusion cage.

Comparison of Short-Term Radiographical and Clinical Outcomes After Posterior Lumbar Interbody Fusion With a 3D Porous Titanium Alloy Cage and a Titanium-Coated PEEK Cage

Study Design: Clinical case series. Objectives: To compare the short-term (≤1 year) radiographical and clinical outcomes between posterior lumbar interbody fusion (PLIF) with a titanium-coated poly-ether-ether-ketone (TCP) cage and PLIF with a three-dimensional porous titanium alloy (PTA) cage. Methods: Overall, 63 patients who had undergone 1- or 2-level PLIF since March 2015 were enrolled (median age, 71 years). The first 34 patients underwent PLIF with TCP cages (until June 2017) and the next 29 patients with PTA cages. Fusion status, vertebral endplate cyst formation (cyst sign: grade 0, none; grade 1, focal; and grade 2, diffuse), cage subsidence (grade 0, <1 mm; grade 1, 1–3 mm; and grade 2, >3 mm), and patient-reported quality of life (QOL) outcomes based on the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) were compared at 6 months and 1 year postoperatively between the 2 cage groups. Results: Cyst sign and cage subsidence grades were significantly lower in the PTA cage group than in the TCP cage group at 6 months postoperatively (cyst sign, p = 0.044; cage subsidence, p = 0.043). In contrast, the fusion rate and surgery effectiveness based on JOABPEQ at both 6 months and 1 year postoperatively were not different between the 2 groups. Conclusions: Patient-reported QOL outcomes were similar between the TCP and PTA cage groups until 1 year postoperatively. However, a higher incidence and severity of postoperative vertebral endplate cyst formation in patients with the TCP cage was a noteworthy radiographical finding.

Long-term radiographic outcomes of expandable versus static cages in transforaminal lumbar interbody fusion

OBJECTIVEPotential advantages of using expandable versus static cages during transforaminal lumbar interbody fusion (TLIF) are not fully established. The authors aimed to compare the long-term radiographic outcomes of expandable versus static TLIF cages.METHODSA retrospective review of 1- and 2-level TLIFs over a 10-year period with expandable and static cages was performed at the University of California, San Francisco. Patients with posterior column osteotomy (PCO) were subdivided. Fusion assessment, cage subsidence, anterior and posterior disc height, foraminal dimensions, pelvic incidence (PI), segmental lordosis (SL), lumbar lordosis (LL), pelvic incidence–lumbar lordosis mismatch (PI-LL), pelvic tilt (PT), sacral slope (SS), and sagittal vertical axis (SVA) were assessed.RESULTSA consecutive series of 178 patients (with a total of 210 levels) who underwent TLIF using either static (148 levels) or expandable cages (62 levels) was reviewed. The mean patient age was 60.3 ± 11.5 years and 62.8 ± 14.1 years for the static and expandable cage groups, respectively. The mean follow-up was 42.9 ± 29.4 months for the static cage group and 27.6 ± 14.1 months for the expandable cage group. Within the 1-level TLIF group, the SL and PI-LL improved with statistical significance regardless of whether PCO was performed; however, the static group with PCOs also had statistically significant improvement in LL and SVA. The expandable cage with PCO subgroup had significant improvement in SL only. All of the foraminal parameters improved with statistical significance, regardless of the type of cages used; however, the expandable cage group had greater improvement in disc height restoration. The incidence of cage subsidence was higher in the expandable group (19.7% vs 5.4%, p = 0.0017). Within the expandable group, the unilateral facetectomy-only subgroup had a 5.6 times higher subsidence rate than the PCO subgroup (26.8% vs 4.8%, p = 0.04). Four expandable cages collapsed over time.CONCLUSIONSExpandable TLIF cages may initially restore disc height better than static cages, but they also have higher rates of subsidence. Unilateral facetectomy alone may result in more subsidence with expandable cages than using bilateral PCO, potentially because of insufficient facet release. Although expandable cages may have more power to induce lordosis and restore disc height than static cages, subsidence and endplate violation may negate any significant gains compared to static cages.

Can posterior stand-alone expandable cages safely restore lumbar lordosis? A minimum 5-year follow-up study

Background Lumbar lordosis (LL) can be restored, and screw-related complications may be avoided with the stand-alone expandable cage method. However, the long-term spinopelvic changes and safety remain unknown. We aimed to elucidate the long-term radiologic outcomes and safety of this technique. Methods Data from patients who underwent multi-level stand-alone expandable cage fusion and 80 patients who underwent screw-assisted fusion between February 2007 and December 2012, with at least 5 years of follow-up, were retrospectively analyzed. Segmental angle and translation, short and whole LL, pelvic incidence, pelvic tilt, sacral slope (SS), sagittal vertical axis, thoracic kyphosis, and presence of subsidence, pseudoarthrosis, retropulsion, cage breakage, proximal junctional kyphosis (PJK), and screw malposition were assessed. The relationship between local, lumbar, and spinopelvic effects was investigated. The implant failure rate was considered a measure of procedure effectiveness and safety. Results In total, 69 cases were included in the stand-alone expandable cage group and 150 cases in the control group. The stand-alone group showed shorter operative time (58.48 ± 11.10 vs 81.43 ± 13.75, P = .00028), lower rate of PJK (10.1% vs 22.5%, P = .03), and restoration of local angle (4.66 ± 3.76 vs 2.03 ± 1.16, P = .000079) than the control group. However, sagittal balance (0.01 ± 2.57 vs 0.50 ± 2.10, P = .07) was not restored, and weakness showed higher rate of subsidence (16.31% vs 4.85%, P = .0018), pseudoarthrosis (9.92% vs 2.42%, P = .02), cage, and retropulsion (3.55% vs 0, P = .01) than the control group. Conclusions Stand-alone expandable cage fusion can restore local lordosis; however, global sagittal balance was not restored. Furthermore, implant safety has not yet been proven.

A comparative study between local bone graft with or without cages in unilateral posterior lumbar interbody fusion (PLIF): a retrospective study

Objective A retrospective study of the clinical and radiological results between local bone graft with a cage and without cage in patients treated with unilateral fixation and posterior lumbar interbody fusion surgery. Methods A total of 52 patients who underwent PLIF in our institution were evaluated from January 2015 to January 2018. 30 of these patients received PLIF with local bone graft combined with using one cage, and 22 patients received PLIF with local bone graft without using cage. The clinical data and perioperative complications of the two groups were recorded. X-ray were taken before, after operation and at the end of follow-up to calculate the height of intervertebral disc and the fusion rate. SUK's criteria were used to evaluate the quality of spinal fusion at the follow-up time. The results between the cage and non- cage group were compared. Results There was no statistical difference in baseline data between the two groups, and The mean follow-up time was 18.43 months in cage group and 17.50 months in non- cage group (P = 0.553). In additions, the significant difference was not found in the comparison of perioperative evaluation data between the two groups, such as operation time (P = 0.299), blood loss (P = 0.342) and incidence of complications (P = 1.000). Furthermore, the significant difference of VAS score cannot be found in preoperation (Pleg=0.731, Plowback=0.786), postoperation (Pleg=0.534, Plowback=0.725) and the final follow-up (Pleg=0.654, Plowback=0.362) between the two groups. The same results were also obtained in the comparison of ODI index (Ppre=0.682, Pfinal=0.712) and intervertebral height (Ppost=0.363, Pfinal=0.094). The final fusion rates were 96.7% (cage group) and 86.4% (non- cage group) respectively, and there was no statistical difference (P = 0.553). Conclusion Local bone graft has the same advantages as a cage in unilateral PLIF. Comparing with local bone graft using cage, we believe that the local bone graft is a more ideal way in unilateral PLIF, and decrease operation cost.

PEEK versus titanium cages in lateral lumbar interbody fusion: a comparative analysis of subsidence

OBJECTIVEThe authors have provided a review of radiographic subsidence after lateral lumbar interbody fusion (LLIF) as a comparative analysis between titanium and polyetheretherketone (PEEK) cages. Many authors describe a reluctance to use titanium cages in spinal fusion secondary to subsidence concerns due to the increased modulus of elasticity of metal cages. The authors intend for this report to provide observational data regarding the juxtaposition of these two materials in the LLIF domain.METHODSA retrospective review of a prospectively maintained database identified 113 consecutive patients undergoing lateral fusion for degenerative indications from January to December 2017. The surgeons performing the cage implantations were two orthopedic spine surgeons and two neurosurgeons. Plain standing radiographs were obtained at 1–2 weeks, 8–12 weeks, and 12 months postoperatively. Using a validated grading system, interbody subsidence into the endplates was graded at these time points on a scale of 0 to III. The primary outcome measure was subsidence between the two groups. Secondary outcomes were analyzed as well.RESULTSOf the 113 patients in the sample, groups receiving PEEK and titanium implants were closely matched at 57 and 56 patients, respectively. Cumulatively, 156 cages were inserted and recombinant human bone morphogenetic protein–2 (rhBMP-2) was used in 38.1%. The average patient age was 60.4 years and average follow-up was 75.1 weeks. Subsidence in the titanium group in this study was less common than in the PEEK cage group. At early follow-up, groups had similar subsidence outcomes. Statistical significance was reached at the 8- to 12-week and 52-week follow-ups, demonstrating more subsidence in the PEEK cage group than the titanium cage group. rhBMP-2 usage was also highly correlated with higher subsidence rates at all 3 follow-up time points. Age was correlated with higher subsidence rates in univariate and multivariate analysis.CONCLUSIONSTitanium cages were associated with lower subsidence rates than PEEK cages in this investigation. Usage of rhBMP-2 was also robustly associated with higher endplate subsidence. Each additional year of age correlated with an increased subsidence risk. Subsidence in LLIF is likely a response to a myriad of factors that include but are certainly not limited to cage material. Hence, the avoidance of titanium interbody implants secondary solely to concerns over a modulus of elasticity likely overlooks other variables of equal or greater importance.