All-solid-state Li-rechargeable batteries using a 500 nm-thick LiCoO2 (LCO) film deposited on two NASICON-type solid electrolyte substrates, LICGC (OHARA Inc.) and Li1.3Al0.3Ti1.7(PO4)3 (LATP), are ...constructed. The postdeposition annealing temperature prior to the cell assembly is critical to produce a stable sharp LCO/electrolyte interface and to develop a strong crystallographic texture in the LCO film, conducive to migration of Li ions. Although the cells deliver a limited discharge capacity, the cells cycled stably for 50 cycles. The analysis of the LCO/electrolyte interfaces after cycling demonstrates that the sharp interface, once formed by proper thermal annealing, will remain stable without any evidence for contamination and with minimal intermixing of the constituent elements during cycling. Hence, although ionic conductivity of the NASICON-type solid electrolyte is lower than that of the sulfide electrolytes, the NACSICON-type electrolytes will maintain a stable interface in contact with a LCO cathode, which should be beneficial to improving the capacity retention as well as the rate capability of the all-solid state cell.
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Single-position lateral interbody fusion surgery has gained traction over the years because of reduced surgical time and improved operating theater workflow. With the introduction of robotics in ...spine surgery, surgeons can place pedicle screws with a high degree of accuracy and efficiency; moreover, the robot allows us to localize the disk space and perform endplate preparation accurately with minimal radiation. In this study, we discuss the potential synergistic benefits of integrating robotic-assisted spine surgery and singleposition prone lateral surgery. We share our technique and provide the operative nuances of using the Mazor X Stealth Edition system (Medtronic, Minneapolis, MN, USA). We highlighted the potential synergistic benefits of integrating both the prone lateral and robotic-assisted surgical techniques, including the challenges encountered. This approach is not meant to replace other techniques or be used in all patients. Instead, it adds to our arsenal for managing spine fusion.
Lumbar interbody fusion procedures have seen a significant evolution over the years, with various approaches being developed to address spinal pathologies and instability, including posterior lumbar ...interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion (ALIF), and lateral lumbar interbody fusion (LLIF). LLIF, a pivotal technique in the field, initially emerged as extreme/direct lateral interbody fusion (XLIF/DLIF) before the development of oblique lumbar interbody fusion (OLIF). To ensure comprehensive circumferential stability, LLIF procedures are often combined with posterior stabilization (PS) using pedicle screws. However, achieving this required repositioning of the patient during the surgical procedure. The advent of single-position surgery (SPS) has revolutionized the procedure by eliminating the need for patient repositioning. With SPS, LLIF along with PS can be performed either in the lateral or prone position, resulting in significantly reduced operative time. Ongoing research endeavors are dedicated to further enhancing LLIF procedures making them even safer and easier. Notably, the integration of robotic technology into SPS has emerged as a game-changer, simplifying surgical processes and positioning itself as a vital asset for the future of spinal fusion surgery. This literature review aims to provide a succinct summary of the evolutionary trajectory of lumbar interbody fusion techniques, with a specific emphasis on its recent advancements.
Retrospective comparative radiological study.
To analyze the difference in early disc height loss following transforaminal and lateral lumbar interbody fusion (TLIF and LLIF).
Minimal disc height ...loss facilitated by the polyaxial screw heads can occur naturally due to mechanical loading following lumbar fusion procedures. This loss does not usually cause any significant foraminal narrowing. However, when there is concomitant cage subsidence, symptomatic foraminal compromise could occur, especially when posterior decompression is not performed. It is not known whether the type of procedure, TLIF or LLIF, could influence this phenomenon.
Retrospectively, patients who underwent TLIF and LLIF for various degenerative conditions were shortlisted. Each of their fused levels with the cage in situ was analyzed independently, and the preoperative, postoperative, and follow-up disc height measurements were compared between the groups. In addition, the total disc height loss since surgery was calculated at final follow-up and was compared between the groups.
Forty-six patients (age, 64.1±8.9 years) with 70 cage levels, 35 in each group, were selected. Age, sex, construct length, preoperative disc height, cage height, and immediate postoperative disc height were similar between the groups. By 3 months, disc height of the TLIF group was significantly less and continued to decrease over time, unlike in the LLIF group. By 1 year, the TLIF group demonstrated greater disc height loss (2.30±1.3 mm) than the LLIF group (0.89±1.1 mm). However, none of the patients in either group had any symptomatic complications throughout follow-up.
Although our study highlights the biomechanical advantage of LLIF over TLIF in maintaining disc height, none of the patients in our cohort had symptomatic complications or implant-related failures. Hence, TLIF, as it incorporates posterior decompression, remains a safe and reliable technique despite the potential for greater disc height loss.
Retrospective radiological analysis.
To analyze the factors influencing early disc height loss following lateral lumbar interbody fusion (LLIF).
Postoperative disc height loss can occur naturally as ...a result of mechanical loading. This phenomenon is enabled by the yielding of the polyaxial screw heads and settling of the cage to the endplates. When coupled with cage subsidence, there can be significant reduction in the foraminal space which ultimately compromises the indirect decompression achieved by LLIF.
Seventy-two cage levels in 37 patients aged 62±10.2 years who underwent single or multilevel LLIF for degenerative spinal conditions were selected. Their preoperative and postoperative follow-up radiographs were used to measure the anterior disc height (ADH), posterior disc height (PDH), mean disc height (MDH), disc space angle (DSA), and segmental angle. Correlations between the loss of disc height and several factors, including age, construct length, preoperative lordosis, postoperative lordosis, disc height, cage dimensions, and cage position, were analyzed.
We found that the lateral interbody cages significantly increased ADH, PDH, MDH, and DSA after surgery (p <0.0001). However, there was a loss of disc height over time. All postoperative disc height parameters, especially the amount of increase in MDH (r =0.413, p <0.0001) after surgery, showed a significant positive association with early disc height loss. The levels demonstrating a significant (≥25%) height loss were those that exhibited a substantial height increase (128.3%, 4.6±3.0 to 10.5±5.6 mm) postoperatively. However, the levels that showed less than 25% height loss were those that exhibited, on average, only a 57.4% height increase post-operatively.
The greater the postoperative increase in disc height, the greater the disc height loss throughout early follow-up. Therefore, achieving an optimal disc height rather than overcorrection is an important surgical strategy to adopt when performing LLIF.
Study DesignRetrospective review.PurposeTo determine the accuracy of thoracolumbar pedicle screw insertion with the routine use of three-dimensional (3D) intraoperative imaging and navigation over a ...large series of screws in an Asian population.Overview of LiteratureThe use of 3D intraoperative imaging and navigation in spinal surgery is aimed at improving the accuracy of pedicle screw insertion. This study analyzed 2,240 pedicle screws inserted with the routine use of intraoperative navigation. It is one of very few studies done on an Asian population with a large series of screws.MethodsPatients who had undergone thoracolumbar pedicle screws insertion using intraoperative imaging and navigation between 2009 and 2017 were retrospectively analyzed. Computed tomography (CT) images acquired after the insertion of pedicle screws were analyzed for breach of the pedicle wall. The pedicle screw breaches were graded according to the Gertzbein classification. The breach rate and revision rate were subsequently calculated.ResultsA total of 2,240 thoracolumbar pedicle screws inserted under the guidance of intraoperative navigation were analyzed, and the accuracy of the insertion was 97.41%. The overall breach rate was 2.59%, the major breach rate was 0.94%, and the intraoperative screw revision rate was 0.7%. There was no incidence of return to the operating theater for revision of screws.ConclusionsThe routine use of 3D navigation and intraoperative CT imaging resulted in consistently accurate pedicle screw placement. This improved the safety of spinal instrumentation and helped in avoiding revision surgery for malpositioned screws.
The magnitude and potential duration of the current coronavirus disease 2019 (COVID-19) pandemic is something that most doctors currently in practice have yet to experience. While considerable ...information regarding COVID-19 is being published every day, it is challenging to filter out the most relevant or appropriate information for our individual practice. The Spine Society of Singapore convened via a teleconference on April 24, 2020 to collaborate on a national level and share collective wisdom in order to tackle the ongoing crisis. In the teleconference, 13 spine surgeons from across various hospitals in Singapore constituted the panel of experts. The following topics were discussed: repurposing of surgeons, continuity of spine services, introduction of telemedicine, triaging of spinal surgeries, preoperative testing, new challenges in performing spine surgery, and preparing for the post-pandemic era. While some issues required only the sharing of best practices, the Delphi panel method was adopted to form a consensus on others. Existing spine specific triage guidelines were debated and a locally accepted set of guidelines was established. Although preoperative testing is currently not performed routinely, the panel voted in favor of its implementation because they concluded that it is vital to protect themselves, their colleagues, and their patients. Solutions to operating room specific concerns were also discussed. This article reflects the opinions and insights shared during this meeting and reviews the evidence relevant to the issues that were raised. The rapid consensus reached during the teleconference has enabled us to be concerted, and thus stronger, in our national efforts to provide the best standard of care via our spine services in these challenging times. We believe that this article will provide some guidance for addressing COVID-19 in spine surgery and encourage other national/regional societies to conduct similar discussions that would help their navigation of this pandemic.
We aimed to determine the 2-year mortality and morbidity rates following spine surgery in elderly patients (age ≥80 years) and to study the associated risk factors.
The records of patients ≥80 years ...of age who underwent spine surgery during the years 2003-2015 at Tan Tock Seng Hospital, Singapore were retrospectively reviewed. Information was collected on their demographic characteristics, comorbidities, diagnosis, general and neurological status, type of surgery, and outcomes. The mortality and morbidity rates over a 2-year period were analyzed. Bivariate analyses were carried out to identify factors associated with mortality.
We selected 47 patients (mean age, 83.3 years; range, 80-91 years) who were followed up for a mean duration of 27.7 months. The mortality rates at 30 days, 6 months, 1 year, and 2 years following surgery were 2.1%, 8.5%, 10.6%, and 12.8%, respectively. The factors significantly associated with mortality included multiple comorbidities, nondegenerative aetiology, and vertebral fractures. The overall morbidity rate was 48.9%, and 17% of this cohort had major complications.
Surgeons should strategize management protocols with due consideration of the mortality and morbidity rates, and be wary of operating on patients with multiple comorbidities, nondegenerative conditions, and vertebral fractures.
STUDY DESIGN.An experimental laboratory-based biomechanical study.
OBJECTIVE.To investigate the correlation between cage size and subsidence and to quantify the resistance to subsidence that a larger ...cage can provide.
SUMMARY OF BACKGROUND DATA.The assumption that a bigger interbody cage confers less subsidence has not been proven. There was no previous study that has shown the superiority of lateral cages to bullet cages in terms of subsidence and none that has quantified the correlation between cage size and subsidence.
METHODS.A cage was compressed between two standardized polyurethane foam blocks at a constant speed. Four sizes of bullet cages used for transforaminal lumbar interbody fusion (TLIF) and six sizes of lateral cages used for lateral lumbar interbody fusion (LLIF) were tested. The force required for a 5 mm subsidence, axial area of cages, and stiffness were analyzed.
RESULTS.A larger cage required a significantly higher force for a 5 mm subsidence. Longer bullet cages required marginal force increments of only 6.2% to 14.6% compared to the smallest bullet cage. Lateral cages, however, required substantially higher increments of force, ranging from 136.4% to 235.7%. The average force of lateral cages was three times that of bullet cages (6426.5 vs. 2115.9 N), and the average stiffness of the LLIF constructs was 3.6 times that of the TLIF constructs (635.5 vs. 2284.2 N/mm). There was a strong correlation between the axial area of cages and the force for a 5 mm subsidence. Every 1 mm increment of axial area corresponded to approximately 8 N increment of force.
CONCLUSION.Cage size correlated strongly with the force required for a 5 mm subsidence. The LLIF constructs required higher force and were stiffer than the TLIF constructs. Among bullet cages, longer cages only required marginal increments of force. Lateral cages, however, required substantially higher force.Level of EvidenceN/A
The effect of Ar plasma pretreatment on the adhesion of the sputter-deposited Cu/Ti film, which was used as a seed layer for subsequent electrodeposition of thick Cu film, on an Ajinomoto build-up ...film (ABF) was evaluated as a function of the plasma power. The Ar plasma pretreatment of the ABF (above 1.2kW) surface resulted in three-fold increase of the peel-off strength (0.70kN/m) compared to the untreated sample (0.23kN/m). The Ar plasma treatment produced a nanoscale worm-like surface roughness on the ABF surface which was responsible for the improved adhesion of the Cu/Ti film. Examination of the fractured surfaces revealed that when the substrate was plasma-treated above 1.2kW, the fracture occurred in the substrate rather than by delamination of the Cu/Ti film. In fact, the fracture of the ABF substrate, which consists of the SiO2 filler embedded in a polymer resin matrix, proceeded mainly by decohesion of the SiO2 microspheres from the polymer matrix. Hence, to further improve the adhesion of the Cu/Ti film, it is advisable to consider strengthening the interface between the SiO2 filler and the resin matrix through surface modification of the SiO2 microspheres.
•ABF substrate was Ar-plasma-treated to improve the adhesion of Cu/Ti film.•Plasma treatment above 1.2kW significantly increased of the peel-off strength.•Nanoscale roughness was found on the Ar plasma-treated ABF surface.•In the untreated sample, the fracture proceeded through the Ti/ABF interface.•In the plasma-treated sample, the fracture occurred through the bulk of the ABF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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