Asian Spine J Search

CLOSE


Asian Spine J > Volume 18(3); 2024 > Article
Chang, Kang, and Cho: Innovative Developments in Lumbar Interbody Cage Materials and Design: A Comprehensive Narrative Review

Abstract

This review comprehensively examines the evolution and current state of interbody cage technology for lumbar interbody fusion (LIF). This review highlights the biomechanical and clinical implications of the transition from traditional static cage designs to advanced expandable variants for spinal surgery. The review begins by exploring the early developments in cage materials, highlighting the roles of titanium and polyetheretherketone in the advancement of LIF techniques. This review also discusses the strengths and limitations of these materials, leading to innovations in surface modifications and the introduction of novel materials, such as tantalum, as alternative materials. Advancements in three-dimensional printing and surface modification technologies form a significant part of this review, emphasizing the role of these technologies in enhancing the biomechanical compatibility and osseointegration of interbody cages. In addition, this review explores the increase in biodegradable and composite materials such as polylactic acid and polycaprolactone, addressing their potential to mitigate long-term implant-related complications. A critical evaluation of static and expandable cages is presented, including their respective clinical and radiological outcomes. While static cages have been a mainstay of LIF, expandable cages are noted for their adaptability to the patient’s anatomy, reducing complications such as cage subsidence. However, this review highlights the ongoing debate and the lack of conclusive evidence regarding the superiority of either cage type in terms of clinical outcomes. Finally, this review proposes future directions for cage technology, focusing on the integration of bioactive substances and multifunctional coatings and the development of patient-specific implants. These advancements aim to further enhance the efficacy, safety, and personalized approach of spinal fusion surgeries. Moreover, this review offers a nuanced understanding of the evolving landscape of cage technology in LIF and provides insights into current practices and future possibilities in spinal surgery.

Introduction

Lumbar interbody fusion (LIF) has emerged as a pivotal technique for managing various spinal pathologies, from degenerative disk disease to spondylolisthesis and spinal instabilities [1]. The clinical relevance of LIF lies in its ability to restore spinal alignment, relieve neurological symptoms, and provide long-term stability, representing a significant advancement in spinal surgery. The evolution of this procedure reflects the persistent search for optimal patient outcomes by balancing surgical invasiveness with efficacy [2].
The choice of interbody cages, which have evolved based on the advancement of biomaterial science, has significantly influenced the efficacy of LIF. Various biomaterials are used in interbody cage development, from traditional materials such as titanium (Ti) and polyetheretherketone (PEEK) to newer materials such as tantalum. Three-dimensional (3D) printing technologies and surface modifications using plasma-spraying technology have taken interbody cage development to the next level [3]. These developments highlight the synergistic relationship between surgical techniques and biomaterials science, which is crucial for improving LIF outcomes. More recently, the introduction of biodegradable materials and the development of the expandable cage technique have further expanded the world of interbody cages.
Despite extensive research and clinical applications of various cages in LIF, gaps remain in understanding the comprehensive effect of cage design and material on patient outcomes. Previous studies have often focused on isolated aspects of cage performance, such as subsidence rates or fusion efficacy, without a holistic view of how these factors interact with overall spinal biomechanics and long-term outcomes [4]. In addition, no consensus has been reached regarding the optimal cage type for specific clinical scenarios, highlighting the need for a more nuanced understanding. This review aimed to bridge these gaps by providing a comprehensive overview of the evolution of cage designs and materials in LIF, critically evaluating their clinical implications, and identifying areas for future research and innovation.

Evolution of Cage Materials in Lumbar Interbody Fusion

1. Early developments and traditional materials

1) Titanium

The evolution of LIF cages began with the development of simple materials and techniques. Earlier cages, primarily composed of stainless steel and Ti, were designed to provide mechanical stability and facilitate bone grafting procedures [5]. Despite challenges such as stress shielding and radiopacity, these materials were chosen for their strength and biocompatibility. The use of cages in spinal procedures was pioneered in the early 1980s, marking a significant shift from traditional bone grafting methods [6,7].
Then, Ti and its alloys became the primary choice for cage fabrication because of their favorable properties, including biocompatibility and ability to promote bone ingrowth. Ti6Al4V is typically chosen for interbody cage production because of its strength, corrosion resistance, low density, biocompatibility, cost-effectiveness, and compatibility with magnetic resonance imaging [810]. To improve fusion rates and reduce complications, such as cage migration or subsidence, advancements in the design and application of Ti cages in the 1990s and early 2000s led to various configurations, such as cylindrical and box-shaped designs [7,11].
Despite its widespread use, Ti presents certain challenges. For example, the mismatch in the elastic modulus between Ti cages and native bone leads to concerns about stress shielding, potentially affecting long-term implant stability and integration. Seaman et al. [12] highlighted that the high elastic modulus of Ti6Al4V can lead to cage subsidence and loss of disk height restoration. In addition, the radiopaque nature of Ti hinders the precise assessment of fusion progression using imaging techniques, prompting the exploration of alternative materials [13]. Recent advancements in 3D printing and surface treatment technologies have enabled the creation of 3D-printed Ti interbody devices with elastic moduli comparable with those of the native bone [1416].

2) Polyetheretherketone

The introduction of PEEK has significantly altered the use of cage materials for lumbar fusion surgery. PEEK is known for its biomechanical compatibility with bone, characterized by an elastic modulus that closely mirrors that of cortical bone and radiolucency, which facilitates postoperative imaging [1719]. Clinical comparisons between PEEK and Ti cages have yielded inconclusive results regarding superiority, with each material exhibiting distinct advantages and disadvantages [12,20]. Compared with Ti alloys, PEEK reduces stress shielding and bone resorption, mitigating implant loosening risks [21,22]. In a meta-analysis, Seaman et al. [12] in 2017 revealed comparable fusion rates between Ti and PEEK interbody cages but highlighted a 3.59-fold higher subsidence likelihood with Ti. Consequently, from the perspective of subsidence and stress shielding, PEEK has advantages over Ti.
However, the hydrophobic characteristics and bioinertness of PEEK may impede its osteointegration [23]. Furthermore, biofilm formation on PEEK cage surfaces impedes binding to the host bone, thereby hindering solid fusion [24]. PEEK cages have also been associated with local inflammation, leading to complications such as bone nonunion and osteolysis [20,25,26]. Efforts to address these shortcomings have led to surface modification of PEEK cages to enhance bioactivity [2729].

3) Tantalum

Tantalum is increasingly used in orthopedics because of its excellent histocompatibility and corrosion resistance and shows promise as an interbody fusion cage biomaterial [3032]. Tantalum and its derivatives are superior to Ti and its alloys in terms of mechanical strength, corrosion resistance, and biocompatibility [3337]. Tantalum exhibits superior osseointegration and antibacterial properties. Among its derivatives, porous tantalum has garnered considerable interest because of its elastic modulus and porous architecture, which closely resembles cancellous bone [38]. Currently, tantalum and its derivatives are effectively employed in artificial joint replacements [39], treatment of femoral head necrosis [40], and dental material applications [41], benefiting various patients. In spinal surgery, the application of tantalum extends to the treatment of infectious bone defects and anterior cervical discectomy and fusion (Fig. 1) [4246].
Results from various clinical studies have demonstrated that porous tantalum cages (PTCs) are effective and safe for spinal surgery, offering several advantages. In anterior LIF (ALIF), PTCs significantly improve lumbar lordosis (LL), reduce back pain, and enhance patients’ quality of life without major complications [47]. Thoracolumbar burst fractures provide superior sagittal profile restoration compared with iliac crest bone grafts, with a lower tendency for correction loss over time [48]. Thus, PTCs could be a viable alternative to autologous bone grafting, potentially avoiding donor-site morbidity. Furthermore, in posterior LIF (PLIF), PTCs show promising results in early bone integration and stability, as indicated by computed tomography (CT) findings of trabecular bone remodeling and lower incidences of vertebral endplate cyst formation compared with Ti-coated PEEK cages [49]. Collectively, these studies have suggested that PTCs can achieve immediate stabilization, facilitate bone fusion, and improve long-term outcomes in spinal surgery.

2. Advancements in 3D printing and surface modification

1) 3D-printing technology

The introduction of 3D-printing technology in spinal cage production marks a pivotal development, allowing the creation of patient-specific implants with intricate, customizable porous structures [50]. It has opened new avenues for designing cages that promote bone ingrowth and vascularization, potentially optimizing the fusion process [51,52]. By using materials such as Ti, 3D-printed structures offer a harmonious blend of mechanical resilience and biological functionality, demonstrating the potential to enhance osseointegration and reduce the risk of non-device-related reoperation [5355]. For example, 3D printing features an elastic modulus closely matching that of the native bone, whereas a conventional Ti alloy cage has an approximately 10-fold higher elastic modulus [1416].
The biomechanical superiority of these 3D-printed cages has led to favorable results in previous clinical studies. Adl Amini et al. [56] showed that 3D-printed Ti cages exhibited a significantly lower early subsidence rate than PEEK cages in patients with standalone lateral LIF (LLIF). Corso et al. [54] analyzed 186 patients (50.5% male; mean age, 59.2±12.5 years) with a minimum follow-up of 6 months. Of these, 96 were treated with 3D-printed Ti implants and 90 with PEEK across 186 implant levels, of which 51.6% used 3D-printed Ti implants [54]. They concluded that in terms of non-device-related reoperation events, 3D-printed Ti cages demonstrated a minimal risk profile compared with traditional non-3D-printed cages. Yang et al. [57] reviewed 150 patients who underwent 1- to 2-level PLIF with a minimum follow-up of 2 years. Compared with PEEK cages, 3D-printed Ti cages achieved significantly higher fusion rates at both postoperative 1 (3D-printed Ti, 86.9%; PEEK, 67.7%; p=0.002) and 2 (3D-printed Ti, 92.9%; PEEK, 82.3%; p=0.037) years [57]. No significant difference was found in the subsidence rates between the two materials. These results suggest that 3D-printed Ti cages are a viable and safe option for PLIF because they provide a stable construct.

2) Surface modifications

The surface properties of interbody cages significantly affect osteointegration. Enhanced surface porosity promotes osteointegration by increasing the surface area and incorporating osteogenic and angiogenic factors such as bone morphogenetic protein-2 (BMP-2) [58]. Previous studies have demonstrated the clinical and radiological advantages of these surface-modified interbody cages. Guyer et al. [59] found that porous Ti exhibited a stronger implant–bone interface than conventional PEEK and allografts, indicating its superior potential for osseointegration and faster achievement of spinal fusion stability.
For porous PEEK cages, Torstrick et al. [60] examined the effects of porosity and pore size on cellular responses to PEEK using micro-CT analysis. They discovered that porous PEEK exhibited increased cell proliferation and cell-mediated mineralization compared with smooth PEEK and Ti [60]. Furthermore, to address PEEK’s inherent hydrophobicity and bioinertness, surface modifications incorporating materials such as hydroxyapatite (HA), calcium silicate (CS), and Ti have been explored to augment PEEK’s bioactivity [2729,61]. Sun et al. [61] investigated the integration of soft tissues with HA/PEEK composite scaffolds. Although the overall bonding strength was influenced mainly by pore size rather than by HA content, HA helped enhance the firm adhesion of soft tissue to PEEK-based composites, a key factor in preventing postoperative effusion [61].
For CS/PEEK cages, Chu et al. [21] used in a goat cervical interbody fusion model and demonstrated that CS/PEEK cages outperformed pure PEEK cages in terms of fusion strength at 12 and 26 weeks in an X-ray analysis. Micro-CT revealed greater new bone ingrowth with CS/PEEK cages, achieving near-complete fusion at 26 weeks. Spine kinematics assays confirmed that these cages also exhibited superior mechanical stability and stiffness. Histological evaluations have highlighted rapid osseointegration and bone formation around CS/PEEK cages [21].
Zhu et al. [62] reported that PEEK cages with Ti and HA coatings, in contrast to uncoated PEEK cages, achieved a significantly higher fusion rates 3 months after single-level transforaminal LIF (TLIF). Two recent meta-analyses comparing Ti-coated PEEK cages with uncoated PEEK cages in lumbar fusion surgeries revealed comparable effects on bone fusion and cage subsidence across all follow-up periods, indicating no significant differences in patient-reported outcomes [27,28]. However, Ti-coated PEEK cages offer the combined benefits of Ti and PEEK: an elastic modulus akin to that of human cortical bone, enhanced osteoid cell growth, and increased cell adhesion space.
According to Torstrick et al. [63], the microstructure of surface-coated PEEK, including its pore morphology, can be precisely manipulated by varying the size of the sodium chloride crystals, with pores adopting the cubic shape of the porogen. Their findings suggested that introducing a porous surface layer to polymeric implants can enhance clinical outcomes while preserving a sufficient load-bearing capacity [63]. Concerns are raised regarding the durability and impaction resistance of the coatings mainly because of substantial impact forces encountered during cage insertion into the intervertebral space. Torstrick et al. [60] also showed that while porous PEEK devices sustained minimal damage during aggressive cervical impaction, Ti-coated PEEK devices experienced a significant loss in their initial Ti coverage [60].

3. Biodegradable and composite materials

Recent advancements have also led to the use of biodegradable materials, such as polylactic acid (PLA) and polycaprolactone (PCL), in the fabrication of spinal cages. These materials are designed to degrade over time and are ideally replaced by natural bone, thus mitigating long-term complications associated with permanent implants [64,65]. Although initial applications face challenges related to mechanical integrity and controlled degradation, recent iterations have shown promising results. This is evident when these materials are used in conjunction with osteoconductive or osteoinductive substances to enhance spinal fusion [66,67]. The evolution of biodegradable cages continues to be a central theme in spinal surgery research, with a focus on optimizing their composition and structure to improve clinical outcomes. Given their ability to reduce long-term complications associated with traditional implants, biodegradable materials such as PLA and PCL are at the forefront of this innovation [3,64,65,68].

1) Polylactic acid

FDA-approved polyesters PLA and PCL were used as primary polymers. The formation of block copolymers such as poly L-lactic acid (PLLA), poly-D, L-lactic acid, and poly(lactic-co-glycolic acid) (PLGA) is achieved through the covalent bonding of different polymer units. Among these, aliphatic polyesters, particularly PLAs, are the most promising [6971]. Previous studies have confirmed the biocompatibility of PLA with dural and neural tissues. More studies have indicated that PLA has no detrimental effects on neuronal cells or pH alterations during PLA implant degradation at the implantation site [7275].
Despite their theoretical advantages, a systematic review focused on biodegradable implants, predominantly polylactides, and their comparison with conventional implants showed that the routine clinical application of absorbable cages lacks sufficient support primarily because of unfavorable long-term fusion rates [76]. The inferior clinical outcomes of biodegradable cages are hypothesized to arise from early degradation and loss of strength, leading to osteolysis and accelerated cage subsidence [77,78].

2) Polycaprolactone

Compared with PLA, which is a bulk-degrading polymer [79], PCL is bioerodible and maintains its initial elastic modulus and 95% mass for up to 12 months [80]. Owing to its superior rheological and viscoelastic properties to other aliphatic polyesters such as PLLA, poly-L-lactide-co-d, and L-lactide acid [81], PCL is a promising candidate for designing slow-degrading implants mainly because of its favorable melt extrusion properties. PCL is distinguished by its superior physicochemical properties, such as structural stability [82], flexibility [83], biocompatibility [84], and biodegradability [85]. In vivo, PCL demonstrates slow degradation, with virtually no molecular-weight changes observed after 6 months [86]. It exhibits greater resistance to degradation in biofluids than other polymers, and its low cost and accessibility add to its advantages [87,88]. PCL enhances cell viability and migration more effectively than rapidly degradable PLGA-3D scaffolds, as demonstrated in in vitro and in vivo studies [89]. Coinciding with advancements in additive biomanufacturing, PCL has gained prominence and become increasingly preferred for fabricating biodegradable cages for spinal fusion.
In large preclinical animal studies, a composite of PCL with ceramics, specifically calcium phosphate (CaP), has emerged as the optimal biomaterial for osseous healing in critical-size tibial defects [90,91]. This combination results in composite biomaterials with improved mechanical properties, controlled degradation rates, and enhanced bioactivity, making them well suited for bone tissue engineering applications [92,93]. Bioactive and bioresorbable scaffolds, made from medical-grade PCL incorporated with 20% β-tricalcium phosphate (TCP) and bioresorbable PCL scaffolds coated with a biomimetic CaP layer plus recombinant human BMP-2 (rhBMP-2), have been effectively used to achieve interbody spinal fusion in both lumbar porcine and thoracic ovine models [66,94]. According to Li et al. [95], autograft-free biodegradable PCL–TCP composite scaffolds facilitated bone tissue ingrowth and maintained mechanical load-bearing capacity after implantation, achieving a spinal fusion efficacy comparable to that of Ti cages with autografts in sheep anterior cervical discectomy and fusion surgeries. Similar to PLA, PCL faces the challenge of inferior mechanical properties compared with permanent materials such as Ti and PEEK. This performance gap becomes more evident as degradation occurs, potentially resulting in reduced stability over time.

3) Future of biodegradable materials

The final goal is to develop cages that offer the best strength and durability with eventual resorption and replacement by natural bone. The key focus areas include addressing issues such as premature degradation and ensuring adequate mechanical support during the critical bone healing and fusion period. Research is geared toward developing materials with optimized degradation rates, improved mechanical strength, and enhanced bioactivity to support the spine until complete osseointegration is achieved. Mechanically, improving the stiffness of PCL scaffolds can be achieved by increasing their mineral content, particularly with HA. According to Shor et al. [96], adding 25% HA to a composite resulted in a 40% increase in the compressive modulus. Furthermore, the stiffness of the PCL/HA mixture increased proportionally with the HA content [97].
Unmodified PCL surfaces exhibited limited cell adhesion, attachment, proliferation, and bioactivity. The use of nano-HA coatings, a type of CaP with a composition and crystal structure akin to human bone, may enhance cytocompatibility [98]. Yong et al. [99] indicated that a CaP-coated PCL-based scaffold with 0.54 μg of rhBMP-2 is as effective as an autograft from the rib head. This generated a conducive environment for thoracic interbody spinal fusion in a sheep thoracic spine model [99]. Recently, Duarte et al. [100] showcased a novel biopolymer of PCL doped with polydopamine and polymethacrylic acid, which, when foamed directly into a bone defect through a specialized high-pressure portable device, achieved immediate stabilization of osseous components. This technique yielded a 3D structure with morphological properties similar to those of the trabecular bone, showing significant potential for instrumentation-free interbody fusion.

4. Static vs. expandable cages in LIF

1) Static cages

Static cages, which are predominantly used in LIF, are pivotal in addressing degenerative spinal disorders [101,102]. The evolution of interbody fusion cages from the earliest threaded BAK designs to the current Ti or PEEK cages has led to shapes that more closely resemble intervertebral space. This design shift offers larger cancellous bone-filling spaces, increased fusion area, enhanced load-bearing capacity, and improved stability. These cages, characterized by their fixed shape and size, are designed for strength and ease of insertion, which are crucial elements in lumbar surgery. Their simple and robust design provides reliable support to the spinal segment, ensuring a consistent approach for various lumbar pathologies [20,103105].
Recently, physicians and patients has placed a growing emphasis on minimally invasive surgical techniques for implanting the largest feasible intervertebral implant through the smallest possible incision with minimal surgical exposure. Compared with the posterior approach, the anterior approach facilitates the use of larger bone cages and grafts, demonstrating enhanced deformity correction capabilities and superior initial stability [106108]. Significant advancements in surgical methods and instrumentation for ALIF and LLIF have been observed in the last 50 years. Critical factors such as cage dimensions, including width, length, height, and contact surface area, are pivotal in maximizing surface contact and ensuring ALIF and LLIF stability [102]. Radiologically, static cages have been instrumental in achieving the desired outcomes in spinal surgeries. Studies have indicated their efficacy in restoring and maintaining segmental lordosis (SL) and disk height, which are critical for preserving the natural curvature and biomechanics of the spine [109111].
Recent developments in endoscopy-assisted spine fusion surgeries have demonstrated clinical and radiological outcomes comparable to those of conventional open surgery [112115], emphasizing the need for specialized cage designs suitable for minimal incision techniques. Recently, Kim et al. [116] demonstrated the feasibility of using a larger cage originally designed for LLIF in biportal endoscopic TLIF to achieve a favorable fusion rate (Fig. 2). With the increasing adoption of minimally invasive techniques, technological advancements have led to the development of interbody devices designed to expand after placement.

2) Expandable cages

Compared with static devices, expandable cages have a minimal profile and can be expanded in situ to reduce iatrogenic endplate damage during cage insertion [117]. The cages were designed to adjust their size and shape to conform to the unique anatomical needs of the patient’s intervertebral space. Their ability to expand after insertion allows for a customized fit and enhanced spinal stabilization, significantly evolving from traditional static cage designs.
Expandable cages can be used for TLIF, ALIF, and LLIF [118]. Although expandable cages are initially implemented in TLIF [119], this procedure can be limited to cases with extensive scarring and high-grade spondylolisthesis [4]. Meanwhile, ALIF and LLIF allow the insertion of wide and large interbody cages, resulting in a greater endplate contact surface than TLIF cages [111]. However, the implantation of such large cages often requires strong impaction when static cages are used. By contrast, expandable LLIF cages obviate the need for the forceful impaction associated with static spacers, thereby potentially reducing the risk of cage subsidence [118].
Radiologically, the use of expandable cages in lumbar fusion has yielded promising results. Expandable cages have been reported to yield superior disk height increments and SL restorations in patients who had undergone lumbar fusion compared with static cages [120124]. A study indicated that these cages effectively maintain or improve SL and disk height, which are critical factors in achieving optimal spinal alignment and biomechanics after surgery. Recent meta-analyses indicate that the design of expandable cages plays a key role in reducing the incidence of cage subsidence in lateral interbody fusion, a frequent complication in lateral lumbar surgeries, helping to maintain the structural integrity of the fused spinal segment (Fig. 3) [125].

3) Comparative studies and current evidence

Whether expandable cages are associated with improved clinical outcomes in patients with lumbar fusion compared with static cages remains unclear [125128]. Three recent meta-analyses assessing the clinical outcomes of expandable cages in TLIF revealed no significant differences in Visual Analog Scale scores for back and leg pain, Oswestry Disability Index (ODI), and fusion rates between static and expandable cages [126128]. Another meta-analysis evaluated the clinical outcomes of expandable cages in both TLIF and PLIF and found no significant differences in ODI, fusion rates, LL, blood loss, and operation time when comparing static with expandable cages [125]. However, the aforementioned meta-analysis documented the role of expandable cages in reducing operative time and intraoperative blood loss, thereby contributing to faster patient recovery and reduced hospital stays [126]. These findings reveal the potential of expandable cages to enhance patient comfort and accelerate postsurgical rehabilitation and recovery.
Regarding radiological outcomes, expandable cages can achieve superior disk height increments and SL restoration in patients who had undergone lumbar fusion compared with static cages [120124,126,127]. However, a meta-analysis on the radiological outcomes of TLIF revealed no statistically significant differences in spinal sagittal alignment (SL and LL) or pelvic parameters [127]. Concurrently, expandable cages have been linked to a reduced incidence of subsidence [121123,129,130]. This reduction may be attributed to their capacity to attain a tailored fit within the intervertebral space. However, two recent meta-analyses focusing on expandable TLIF cages did not demonstrate any significant difference in cage subsidence between static and expandable cages [126,127]. Frisch et al. [117] and Li et al. [131,132] reported that expandable LLIF cages resulted in an expandable group with a significantly lower subsidence rate. They also reported increased postoperative disk space measurements compared with preoperative levels, noting a statistically more significant change in static than in expandable cages [117,131,132]. This difference may be due to the overdistraction required for static cage insertion. Consequently, an expandable LLIF cage that avoids forceful insertion may help prevent subsidence. More studies are needed to determine whether expandable cages exhibit variability in their subsidence prevention efficacy based on the surgical technique employed and understand the underlying reasons for such differences.
The association between expandable cages and improved clinical outcomes compared with fixed cages in patients who had undergone lumbar fusion remains uncertain. Expandable cages have several advantages in certain aspects. Therefore, choosing between static and expandable cages should be based on patient-specific factors and surgical objectives. Surgeons must weigh these findings against individual patient needs, surgical goals, and specific pathology being addressed to choose the most appropriate interbody device.

4) Future directions in cage technology for LIF

As technology continues to evolve, future studies should explore the integration of bioactive substances into 3D-printed cages. Embedding growth factors or osteoinductive materials within the scaffold structure may further promote bone growth and fusion [133,134]. In addition, ongoing advancements in materials science may introduce new biocompatible materials that enhance the functionality of 3D-printed cages. The combination of a customizable design and improved material properties and integration of bioactive agents are poised to significantly advance the efficacy and safety of LIF procedures, paving the way for more personalized and effective spinal treatments.
Research has increasingly focused on multifunctional coatings that combine osteoinductive properties with antibacterial capabilities. The development of dual-function coatings could revolutionize LIF procedures by enhancing bone growth and reducing risks [135]. Future studies must explore the incorporation of novel materials and bioactive agents into these coatings, potentially leading to even greater improvements in clinical outcomes. As this field evolves, the focus will likely shift toward customizing coatings based on specific patient needs and surgical context, further personalizing LIF treatments and improving patient-specific outcomes.
Continuous innovations in material science and technology are likely to shape the future of LIF. A study focused on developing materials that directly deliver targeted therapeutic agents, such as growth factors or antibiotics, to the fusion site [20]. In addition, the exploration of personalized implants tailored to each patient’s specific anatomical and pathological conditions represents a significant advancement in patient-specific care. These emerging materials and technologies can significantly improve the efficacy, safety, and patient outcomes of spinal fusion surgeries, thus marking a new era for treating spinal disorders.

Conclusions

The dynamic evolution of cage technology in LIF represents a significant advancement in the management of spinal disorders, offering spine surgeons diverse tools tailored to optimize patient outcomes. The transition from the use of traditional materials to the utilization of innovative synthetic, biodegradable, and composite materials reflects a deeper understanding of biomechanics and materials science. Advancements in 3D printing and customizable solutions have ushered in an era of patient-specific implants, ensuring a closer match between anatomical and pathological conditions. Investigations on surface modifications, bioactive coatings, and emerging materials such as smart biomaterials signifies a paradigm shift toward implants that support structural integrity and actively participate in the biological healing process. Moreover, the development of static and expandable cages, each with distinct clinical and radiological outcomes, highlights the importance of personalized treatment strategies for spinal surgery. These technological advancements integrated with clinical expertise can significantly enhance the efficacy, safety, and overall success of spinal fusion procedures, marking a pivotal step forward in orthopedic surgery.

Notes

Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Author Contributions

Conceptualization: SYC, DHK; data curation: SYC, DHK; formal analysis: SYC, DHK; methodology: SYC, DHK; project administration: SYC, DHK; visualization: SYC, DHK; writing–original draft: SYC, SC, DHK; writing–review & editing: SYC, SC, DHK; and final approval of the manuscript: all authors.

Fig. 1
(A–D) Examples of tantalum cages. Representative cases illustrate the application of tantalum cages, such as in a 68-year-old male patient where a tantalum cage was placed in the L1–2 intervertebral space, resulting in artifact generation on postoperative computed tomography and magnetic resonance imaging.
asj-2023-0407f1.jpg
Fig. 2
The lumbar interbody cages vary in design and size. (A) A titanium cage suitable for transforaminal lumbar interbody fusion (LIF) and posterior LIF. (B) A larger polyetheretherketone cage designed for oblique LIF, lateral LIF, or anterior LIF. Views (C, D) present lateral and axial perspectives of two distinct cages. The larger cage measures 15 mm in width and 40 mm in length, making it suitable for endoscopic transforaminal lumbar interbody fusion, while the smaller cage’s dimensions are 10 mm by 32 mm. From Kim JE, et al. World Neurosurg 2023;178:e666–72 [116], with permission from the authors.
asj-2023-0407f2.jpg
Fig. 3
(A) A 71-year-old female patient underwent L4–5 oblique lumbar interbody fusion (OLIF) with a static polyetheretherketone cage and exhibited cage subsidence in the 3-month postoperative follow-up X-ray. (B) A 75-year-old female patient received L4–5 OLIF with an expandable cage and has sustained proper alignment without any signs of cage subsidence for 3 months.
asj-2023-0407f3.jpg

References

1. Ravindra VM, Senglaub SS, Rattani A, et al. Degenerative lumbar spine disease: estimating global incidence and worldwide volume. Global Spine J 2018;8:784–94.
crossref pmid pmc pdf
2. Hee HT, Castro FP Jr, Majd ME, Holt RT, Myers L. Anterior/posterior lumbar fusion versus transforaminal lumbar interbody fusion: analysis of complications and predictive factors. J Spinal Disord 2001;14:533–40.
crossref pmid
3. Laubach M, Kobbe P, Hutmacher DW. Biodegradable interbody cages for lumbar spine fusion: current concepts and future directions. Biomaterials 2022;288:121699.
crossref pmid
4. Mobbs RJ, Phan K, Malham G, Seex K, Rao PJ. Lumbar interbody fusion: techniques, indications and comparison of interbody fusion options including PLIF, TLIF, MI-TLIF, OLIF/ATP, LLIF and ALIF. J Spine Surg 2015;1:2–18.
pmid pmc
5. Dhall SS, Choudhri TF, Eck JC, et al. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 5: correlation between radiographic outcome and function. J Neurosurg Spine 2014;21:31–6.
crossref pmid
6. Bagby G. The Bagby and Kuslich (BAK) method of lumbar interbody fusion. Spine (Phila Pa 1976) 1999;24:1857.
pmid
7. Kuslich SD, Ulstrom CL, Griffith SL, Ahern JW, Dowdle JD. The Bagby and Kuslich method of lumbar interbody fusion: history, techniques, and 2-year follow-up results of a United States prospective, multicenter trial. Spine (Phila Pa 1976) 1998;23:1267–79.
pmid
8. Wang Q, Zhou P, Liu S, et al. Multi-scale surface treatments of titanium implants for rapid osseointegration: a review. Nanomaterials (Basel) 2020;10:1244.
crossref pmid pmc
9. Chong E, Pelletier MH, Mobbs RJ, Walsh WR. The design evolution of interbody cages in anterior cervical discectomy and fusion: a systematic review. BMC Musculoskelet Disord 2015;16:99.
crossref pmid pmc pdf
10. Alvarez K, Nakajima H. Metallic scaffolds for bone regeneration. Materials (Basel) 2009;2:790–832.
crossref pmc
11. Brantigan JW, Steffee AD, Geiger JM. A carbon fiber implant to aid interbody lumbar fusion: mechanical testing. Spine (Phila Pa 1976) 1991;16(6 Suppl): S277–82.
pmid
12. Seaman S, Kerezoudis P, Bydon M, Torner JC, Hitchon PW. Titanium vs. polyetheretherketone (PEEK) interbody fusion: meta-analysis and review of the literature. J Clin Neurosci 2017;44:23–9.
crossref pmid
13. Niu CC, Liao JC, Chen WJ, Chen LH. Outcomes of interbody fusion cages used in 1 and 2-levels anterior cervical discectomy and fusion: titanium cages versus polyetheretherketone (PEEK) cages. J Spinal Disord Tech 2010;23:310–6.
pmid
14. Wu SH, Li Y, Zhang YQ, et al. Porous titanium-6 aluminum-4 vanadium cage has better osseointegration and less micromotion than a poly-ether-ether-ketone cage in sheep vertebral fusion. Artif Organs 2013;37:E191–201.
crossref pmid
15. Carpenter RD, Klosterhoff BS, Torstrick FB, et al. Effect of porous orthopaedic implant material and structure on load sharing with simulated bone ingrowth: a finite element analysis comparing titanium and PEEK. J Mech Behav Biomed Mater 2018;80:68–76.
crossref pmid pmc
16. Warnke PH, Douglas T, Wollny P, et al. Rapid prototyping: porous titanium alloy scaffolds produced by selective laser melting for bone tissue engineering. Tissue Eng Part C Methods 2009;15:115–24.
crossref pmid
17. Ma R, Tang T. Current strategies to improve the bioactivity of PEEK. Int J Mol Sci 2014;15:5426–45.
crossref pmid pmc
18. Mobbs RJ, Phan K, Assem Y, Pelletier M, Walsh WR. Combination Ti/PEEK ALIF cage for anterior lumbar interbody fusion: early clinical and radiological results. J Clin Neurosci 2016;34:94–9.
crossref pmid
19. Olivares-Navarrete R, Hyzy SL, Slosar PJ, Schneider JM, Schwartz Z, Boyan BD. Implant materials generate different peri-implant inflammatory factors: poly-ether-ether-ketone promotes fibrosis and microtextured titanium promotes osteogenic factors. Spine (Phila Pa 1976) 2015;40:399–404.
pmid pmc
20. D’Antonio N, Lambrechts MJ, Heard J, et al. Effect of interbody composition on the development of pseudarthrosis following anterior cervical discectomy and fusion. Asian Spine J 2023;17:518–28.
crossref pmid pmc pdf
21. Chu L, Li R, Liao Z, et al. Highly effective bone fusion induced by the interbody cage made of calcium silicate/polyetheretherketone in a goat model. ACS Biomater Sci Eng 2019;5:2409–16.
crossref pmid
22. McGilvray KC, Easley J, Seim HB, et al. Bony ingrowth potential of 3D-printed porous titanium alloy: a direct comparison of interbody cage materials in an in vivo ovine lumbar fusion model. Spine J 2018;18:1250–60.
crossref pmid pmc
23. Nemoto O, Asazuma T, Yato Y, Imabayashi H, Yasuoka H, Fujikawa A. Comparison of fusion rates following transforaminal lumbar interbody fusion using polyetheretherketone cages or titanium cages with transpedicular instrumentation. Eur Spine J 2014;23:2150–5.
crossref pmid pdf
24. McGilvray KC, Waldorff EI, Easley J, et al. Evaluation of a polyetheretherketone (PEEK) titanium composite interbody spacer in an ovine lumbar interbody fusion model: biomechanical, microcomputed tomographic, and histologic analyses. Spine J 2017;17:1907–16.
crossref pmid
25. Mokawem M, Katzouraki G, Harman CL, Lee R. Lumbar interbody fusion rates with 3D-printed lamellar titanium cages using a silicate-substituted calcium phosphate bone graft. J Clin Neurosci 2019;68:134–9.
crossref pmid
26. Cheng BC, Jaffee S, Averick S, Swink I, Horvath S, Zhukauskas R. A comparative study of three biomaterials in an ovine bone defect model. Spine J 2020;20:457–64.
crossref pmid
27. Li S, Li X, Bai X, Wang Y, Han P, Li H. Titanium-coated polyetheretherketone cages vs. polyetheretherketone cages in lumbar interbody fusion: a systematic review and meta-analysis. Exp Ther Med 2023;25:305.
crossref pmid pmc
28. Lv ZT, Xu Y, Cao B, et al. Titanium-coated PEEK versus uncoated PEEK cages in lumbar interbody fusion: a systematic review and meta-analysis of randomized controlled trial. Clin Spine Surg 2023;36:198–209.
pmid
29. Muthiah N, Yolcu YU, Alan N, Agarwal N, Hamilton DK, Ozpinar A. Evolution of polyetheretherketone (PEEK) and titanium interbody devices for spinal procedures: a comprehensive review of the literature. Eur Spine J 2022;31:2547–56.
crossref pmid pdf
30. Zardiackas LD, Parsell DE, Dillon LD, Mitchell DW, Nunnery LA, Poggie R. Structure, metallurgy, and mechanical properties of a porous tantalum foam. J Biomed Mater Res 2001;58:180–7.
crossref pmid
31. Veillette CJ, Mehdian H, Schemitsch EH, McKee MD. Survivorship analysis and radiographic outcome following tantalum rod insertion for osteonecrosis of the femoral head. J Bone Joint Surg Am 2006;88(Suppl 3): 48–55.
crossref pmid
32. Wang X, Ning B, Pei X. Tantalum and its derivatives in orthopedic and dental implants: osteogenesis and antibacterial properties. Colloids Surf B Biointerfaces 2021;208:112055.
crossref pmid
33. Lu M, Xu S, Lei ZX, et al. Application of a novel porous tantalum implant in rabbit anterior lumbar spine fusion model: in vitro and in vivo experiments. Chin Med J (Engl) 2019;132:51–62.
pmid pmc
34. Piglionico S, Bousquet J, Fatima N, Renaud M, Collart-Dutilleul PY, Bousquet P. Porous tantalum vs. titanium implants: enhanced mineralized matrix formation after stem cells proliferation and differentiation. J Clin Med 2020;9:3657.
crossref pmid pmc
35. Bencharit S, Byrd WC, Altarawneh S, et al. Development and applications of porous tantalum trabecular metal-enhanced titanium dental implants. Clin Implant Dent Relat Res 2014;16:817–26.
crossref pmid pmc
36. Li X, Wang L, Yu X, et al. Tantalum coating on porous Ti6Al4V scaffold using chemical vapor deposition and preliminary biological evaluation. Mater Sci Eng C Mater Biol Appl 2013;33:2987–94.
crossref pmid
37. Fan H, Deng S, Tang W, et al. Highly porous 3D printed tantalum scaffolds have better biomechanical and microstructural properties than titanium scaffolds. Biomed Res Int 2021;2021:2899043.
crossref pmid pmc pdf
38. Minagar S, Berndt CC, Wang J, Ivanova E, Wen C. A review of the application of anodization for the fabrication of nanotubes on metal implant surfaces. Acta Biomater 2012;8:2875–88.
crossref pmid
39. Hampton M, Mansoor J, Getty J, Sutton PM. Uncemented tantalum metal components versus cemented tibial components in total knee arthroplasty: 11- to 15-year outcomes of a single-blinded randomized controlled trial. Bone Joint J 2020;102-B:1025–32.
crossref pmid pdf
40. Hu R, Lei P, Li B, et al. Real-time computerised tomography assisted porous tantalum implant in ARCO stage I-II non-traumatic osteonecrosis of the femoral head: minimum five-year follow up. Int Orthop 2018;42:1535–44.
crossref pmid pdf
41. Zamparini F, Siboni F, Prati C, Taddei P, Gandolfi MG. Properties of calcium silicate-monobasic calcium phosphate materials for endodontics containing tantalum pentoxide and zirconium oxide. Clin Oral Investig 2019;23:445–57.
crossref pmid pdf
42. Hua L, Lei T, Qian H, Zhang Y, Hu Y, Lei P. 3D-printed porous tantalum: recent application in various drug delivery systems to repair hard tissue defects. Expert Opin Drug Deliv 2021;18:625–34.
crossref pmid
43. Wang Y, Wei R, Subedi D, Jiang H, Yan J, Li J. Tantalum fusion device in anterior cervical discectomy and fusion for treatment of cervical degeneration disease: a systematic review and meta-analysis. Clin Spine Surg 2020;33:111–9.
pmid
44. Tome-Bermejo F, Alvarez-Galovich L, Pinera-Parrilla AR, et al. Anterior 1–2 level cervical corpectomy and fusion for degenerative cervical disease: a retrospective study with lordotic porous tantalum cages. long-term changes in sagittal alignment and their clinical and radiological implications after cage subsidence. Int J Spine Surg 2022;16:222–32.
crossref pmid pmc
45. Mazzucchi E, La Rocca G, Perna A, et al. Single-level anterior cervical discectomy and interbody fusion: a comparison between porous tantalum and polyetheretherketone cages. J Pers Med 2022;12:986.
crossref pmid pmc
46. Fernandez-Fairen M, Alvarado E, Torres A. Eleven-year follow-up of two cohorts of patients comparing stand-alone porous tantalum cage versus autologous bone graft and plating in anterior cervical fusions. World Neurosurg 2019;122:e156–67.
crossref pmid
47. Butler JS, Lui DF, Malhotra K, et al. 360-Degree complex primary reconstruction using porous tantalum cages for adult degenerative spinal deformity. Global Spine J 2019;9:613–8.
crossref pmid pmc pdf
48. Jordan MC, Jansen H, Meffert RH, Heintel TM. Comparing porous tantalum fusion implants and iliac crest bone grafts for spondylodesis of thoracolumbar burst fractures: prospectice cohort study. Sci Rep 2021;11:17409.
crossref pmid pmc pdf
49. Segi N, Nakashima H, Shinjo R, et al. Trabecular bone remodeling after posterior lumbar interbody fusion: comparison of three-dimensional porous tantalum and titanium-coated polyetheretherketone interbody cages. Global Spine J 2023 Apr 15 [Epub]. https://doi.org/10.1177/21925682231170613
crossref
50. Li P, Jiang W, Yan J, et al. A novel 3D printed cage with microporous structure and in vivo fusion function. J Biomed Mater Res A 2019;107:1386–92.
crossref pmid pdf
51. Fogel G, Martin N, Lynch K, et al. Subsidence and fusion performance of a 3D-printed porous interbody cage with stress-optimized body lattice and microporous endplates: a comprehensive mechanical and biological analysis. Spine J 2022;22:1028–37.
crossref pmid
52. Xiao X, Wang W, Liu D, et al. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways. Sci Rep 2015;5:9409.
crossref pmid pmc pdf
53. Patel NA, O’Bryant S, Rogers CD, et al. Three-dimensional-printed titanium versus polyetheretherketone cages for lumbar interbody fusion: a systematic review of comparative in vitro, animal, and human studies. Neurospine 2023;20:451–63.
crossref pmid pmc pdf
54. Corso KA, Kothari P, Corrado K, Michielli A, Ruppenkamp J, Bowden D. Early revision events among patients with a three dimensional (3D) printed cellular titanium or PEEK (polyetheretherketone) spinal cage for single-level lumbar spinal fusion. Expert Rev Med Devices 2022;19:195–201.
crossref pmid
55. Tan KH, Chua CK, Leong KF, Naing MW, Cheah CM. Fabrication and characterization of three-dimensional poly(ether- ether-ketone)/-hydroxyapatite biocomposite scaffolds using laser sintering. Proc Inst Mech Eng H 2005;219:183–94.
crossref pmid pdf
56. Adl Amini D, Okano I, Oezel L, et al. Evaluation of cage subsidence in standalone lateral lumbar interbody fusion: novel 3D-printed titanium versus polyetheretherketone (PEEK) cage. Eur Spine J 2021;30:2377–84.
crossref pmid pdf
57. Yang JJ, Kim DM, Park S. Comparison of fusion, subsidence, and clinical results between 3D-printed porous titanium cage and polyetheretherketone cage in posterior lumbar interbody fusion: a minimum of 2 years follow-up. World Neurosurg 2023 Jul 5 [Epub]. https://doi.org/10.1016/j.wneu.2023.06.132
crossref
58. Olivares-Navarrete R, Gittens RA, Schneider JM, et al. Osteoblasts exhibit a more differentiated phenotype and increased bone morphogenetic protein production on titanium alloy substrates than on poly-ether-ether-ketone. Spine J 2012;12:265–72.
crossref pmid pmc
59. Guyer RD, Abitbol JJ, Ohnmeiss DD, Yao C. Evaluating osseointegration into a deeply porous titanium scaffold: a biomechanical comparison with PEEK and allograft. Spine (Phila Pa 1976) 2016;41:E1146–50.
pmid
60. Torstrick FB, Klosterhoff BS, Westerlund LE, et al. Impaction durability of porous polyether-ether-ketone (PEEK) and titanium-coated PEEK interbody fusion devices. Spine J 2018;18:857–65.
crossref pmid
61. Sun C, Zhao H, Wang L, et al. Additive manufactured polyether-ether-ketone composite scaffolds with hydroxyapatite filler and porous structure promoted the integration with soft tissue. Biomater Adv 2022;141:213119.
crossref pmid
62. Zhu C, He M, Mao L, et al. Titanium interlayer-mediated hydroxyapatite-coated polyetheretherketone cage in transforaminal lumbar interbody fusion surgery. BMC Musculoskelet Disord 2021;22:918.
crossref pmid pmc pdf
63. Torstrick FB, Evans NT, Stevens HY, Gall K, Guldberg RE. Do surface porosity and pore size influence mechanical properties and cellular response to PEEK? Clin Orthop Relat Res 2016;474:2373–83.
crossref pmid pmc pdf
64. Pina S, Ferreira JM. Bioresorbable plates and screws for clinical applications: a review. J Healthc Eng 2012;3:243–60.
crossref pdf
65. Dusselier M, Van Wouwe P, Dewaele A, Jacobs PA, Sels BF. Green chemistry: shape-selective zeolite catalysis for bioplastics production. Science 2015;349:78–80.
crossref pmid
66. Yong MR, Saifzadeh S, Askin GN, Labrom RD, Hutmacher DW, Adam CJ. Establishment and characterization of an open mini-thoracotomy surgical approach to an ovine thoracic spine fusion model. Tissue Eng Part C Methods 2014;20:19–27.
crossref pmid
67. Abbah SA, Lam CX, Hutmacher DW, Goh JC, Wong HK. Biological performance of a polycaprolactone-based scaffold used as fusion cage device in a large animal model of spinal reconstructive surgery. Biomaterials 2009;30:5086–93.
crossref pmid
68. Vert M. Polymeric biomaterials: strategies of the past vs. strategies of the future. Prog Polym Sci 2007;32:755–61.
crossref
69. Li LY, Cui LY, Zeng RC, et al. Advances in functionalized polymer coatings on biodegradable magnesium alloys: a review. Acta Biomater 2018;79:23–36.
crossref pmid
70. Zhou H, Lawrence JG, Bhaduri SB. Fabrication aspects of PLA-CaP/PLGA-CaP composites for orthopedic applications: a review. Acta Biomater 2012;8:1999–2016.
crossref pmid
71. Song Y, Li Y, Song W, Yee K, Lee KY, Tagarielli VL. Measurements of the mechanical response of unidirectional 3D-printed PLA. Mater Des 2017;123:154–64.
crossref
72. de Medinaceli L, al Khoury R, Merle M. Large amounts of polylactic acid in contact with divided nerve sheaths have no adverse effects on regeneration. J Reconstr Microsurg 1995;11:43–9.
crossref pmid
73. Gautier SE, Oudega M, Fragoso M, et al. Poly(alpha-hydroxyacids) for application in the spinal cord: resorbability and biocompatibility with adult rat Schwann cells and spinal cord. J Biomed Mater Res 1998;42:642–54.
crossref pmid
74. Lundgren D, Nyman S, Mathisen T, Isaksson S, Klinge B. Guided bone regeneration of cranial defects, using biodegradable barriers: an experimental pilot study in the rabbit. J Craniomaxillofac Surg 1992;20:257–60.
crossref pmid
75. van der Elst M, Dijkema AR, Klein CP, Patka P, Haarman HJ. Tissue reaction on PLLA versus stainless steel interlocking nails for fracture fixation: an animal study. Biomaterials 1995;16:103–6.
crossref pmid
76. Koutserimpas C, Alpantaki K, Chatzinikolaidou M, Chlouverakis G, Dohm M, Hadjipavlou AG. The effectiveness of biodegradable instrumentation in the treatment of spinal fractures. Injury 2018;49:2111–20.
crossref pmid
77. Epari DR, Kandziora F, Duda GN. Stress shielding in box and cylinder cervical interbody fusion cage designs. Spine (Phila Pa 1976) 2005;30:908–14.
crossref pmid
78. Jiya T, Smit T, Deddens J, Mullender M. Posterior lumbar interbody fusion using nonresorbable poly-ether-ether-ketone versus resorbable poly-L-lactide-co-D,L-lactide fusion devices: a prospective, randomized study to assess fusion and clinical outcome. Spine (Phila Pa 1976) 2009;34:233–7.
pmid
79. Karjalainen T, Hiljanen-Vainio M, Malin M, Seppala J. Biodegradable lactone copolymers: III. Mechanical properties of e-caprolactone and lactide copolymers after hydrolysis in vitro. J Appl Polym Sci 1996;59:1299–304.
crossref
80. Pitt CG, Chasalow FI, Hibionada YM, Klimas DM, Schindler A. Aliphatic polyesters: I. The degradation of poly (ε-caprolactone) in vivo. J Appl Polym Sci 1981;26:3779–87.
crossref
81. Woodruff MA, Hutmacher DW. The return of a forgotten polymer: polycaprolactone in the 21st century. Prog Polym Sci 2010;35:1217–56.
crossref
82. Domingos M, Intranuovo F, Gloria A, et al. Improved osteoblast cell affinity on plasma-modified 3-D extruded PCL scaffolds. Acta Biomater 2013;9:5997–6005.
crossref pmid
83. Dash TK, Konkimalla VB. Poly-є-caprolactone based formulations for drug delivery and tissue engineering: a review. J Control Release 2012;158:15–33.
crossref pmid
84. Wong HM, Zhao Y, Leung FK, et al. Functionalized polymeric membrane with enhanced mechanical and biological properties to control the degradation of magnesium alloy. Adv Healthc Mater 2017;6:1601269.
crossref pdf
85. Vandrovcova M, Douglas TE, Mroz W, et al. Pulsed laser deposition of magnesium-doped calcium phosphate coatings on porous polycaprolactone scaffolds produced by rapid prototyping. Mater Lett 2015;148:178–83.
crossref
86. Lam CX, Hutmacher DW, Schantz JT, Woodruff MA, Teoh SH. Evaluation of polycaprolactone scaffold degradation for 6 months in vitro and in vivo. J Biomed Mater Res A 2009;90:906–19.
crossref pmid
87. Yazdimamaghani M, Razavi M, Vashaee D, Pothineni VR, Rajadas J, Tayebi L. Significant degradability enhancement in multilayer coating of polycaprolactone-bioactive glass/gelatin-bioactive glass on magnesium scaffold for tissue engineering applications. Appl Surf Sci 2015;338:137–45.
crossref
88. Williams JM, Adewunmi A, Schek RM, et al. Bone tissue engineering using polycaprolactone scaffolds fabricated via selective laser sintering. Biomaterials 2005;26:4817–27.
crossref pmid
89. Sung HJ, Meredith C, Johnson C, Galis ZS. The effect of scaffold degradation rate on three-dimensional cell growth and angiogenesis. Biomaterials 2004;25:5735–42.
crossref pmid
90. Reichert JC, Wullschleger ME, Cipitria A, et al. Custom-made composite scaffolds for segmental defect repair in long bones. Int Orthop 2011;35:1229–36.
crossref pmid pmc pdf
91. Henkel J, Medeiros Savi F, Berner A, et al. Scaffold-guided bone regeneration in large volume tibial segmental defects. Bone 2021;153:116163.
crossref pmid
92. Hajiali F, Tajbakhsh S, Shojaei A. Fabrication and properties of polycaprolactone composites containing calcium phosphate-based ceramics and bioactive glasses in bone tissue engineering: a review. Polym Rev 2018;58:164–207.
crossref
93. Bartnikowski M, Dargaville TR, Ivanovski S, Hutmacher DW. Degradation mechanisms of polycaprolactone in the context of chemistry, geometry and environment. Prog Polym Sci 2019;96:1–20.
crossref
94. Abbah SA, Lam CX, Hutmacher DW, Goh JC, Wong HK. Biological performance of a polycaprolactone-based scaffold used as fusion cage device in a large animal model of spinal reconstructive surgery. Biomaterials 2009;30:5086–93.
crossref pmid
95. Li Y, Wu ZG, Li XK, et al. A polycaprolactone-tricalcium phosphate composite scaffold as an autograft-free spinal fusion cage in a sheep model. Biomaterials 2014;35:5647–59.
crossref pmid
96. Shor L, Guceri S, Wen X, Gandhi M, Sun W. Fabrication of three-dimensional polycaprolactone/hydroxyapatite tissue scaffolds and osteoblast-scaffold interactions in vitro. Biomaterials 2007;28:5291–7.
crossref pmid
97. Ang KC, Leong KF, Chua CK, Chandrasekaran M. Compressive properties and degradability of poly(epsilon-caprolatone)/hydroxyapatite composites under accelerated hydrolytic degradation. J Biomed Mater Res A 2007;80:655–60.
pmid
98. Abdal-hay A, Amna T, Lim JK. Biocorrosion and osteoconductivity of PCL/nHAp composite porous film-based coating of magnesium alloy. Solid State Sci 2013;18:131–40.
crossref
99. Yong MR, Saifzadeh S, Woodruff M, et al. Biological performance of a polycaprolactone-based scaffold plus recombinant human morphogenetic protein-2 (rhBMP-2) in an ovine thoracic interbody fusion model. Eur Spine J 2014;23:650–7.
crossref pmid pmc pdf
100. Duarte RM, Correia-Pinto J, Reis RL, Duarte AR. Advancing spinal fusion: interbody stabilization by in situ foaming of a chemically modified polycaprolactone. J Tissue Eng Regen Med 2020;14:1465–75.
crossref pmid pdf
101. Jain S, Eltorai AE, Ruttiman R, Daniels AH. Advances in spinal interbody cages. Orthop Surg 2016;8:278–84.
crossref pmid pmc pdf
102. Phan K, Mobbs RJ. Evolution of design of interbody cages for anterior lumbar interbody fusion. Orthop Surg 2016;8:270–7.
crossref pmid pmc pdf
103. McAfee PC, DeVine JG, Chaput CD, et al. The indications for interbody fusion cages in the treatment of spondylolisthesis: analysis of 120 cases. Spine (Phila Pa 1976) 2005;30(6 Suppl): S60–5.

104. Lambrechts MJ, Heard J, D’Antonio N, et al. A comparison of radiographic alignment between bilateral and unilateral interbody cages in patients undergoing transforaminal lumbar interbody fusion. Asian Spine J 2023;17:666–75.
crossref pmid pmc pdf
105. Mittal S, Sudhakar PV, Ahuja K, et al. Deformity correction with interbody fusion using lateral versus posterior approach in adult degenerative scoliosis: a systematic review and observational meta-analysis. Asian Spine J 2023;17:431–51.
crossref pmid pmc pdf
106. Lee CS, Hwang CJ, Lee DH, Kim YT, Lee HS. Fusion rates of instrumented lumbar spinal arthrodesis according to surgical approach: a systematic review of randomized trials. Clin Orthop Surg 2011;3:39–47.
crossref pmid pmc
107. Hueng DY, Chung TT, Chuang WH, Hsu CP, Chou KN, Lin SC. Biomechanical effects of cage positions and facet fixation on initial stability of the anterior lumbar interbody fusion motion segment. Spine (Phila Pa 1976) 2014;39:E770–6.
crossref pmid
108. Phan K, Thayaparan GK, Mobbs RJ. Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion: systematic review and meta-analysis. Br J Neurosurg 2015;29:705–11.
crossref pmid
109. Fujibayashi S, Hynes RA, Otsuki B, Kimura H, Takemoto M, Matsuda S. Effect of indirect neural decompression through oblique lateral interbody fusion for degenerative lumbar disease. Spine (Phila Pa 1976) 2015;40:E175–82.
crossref pmid
110. Seuk JW, Bae J, Shin SH, Lee SH. Long-term minimum clinically important difference in health-related quality of life scores after instrumented lumbar interbody fusion for low-grade isthmic spondylolisthesis. World Neurosurg 2018;117:e493–9.
crossref pmid
111. Kim H, Chang BS, Chang SY. Pearls and pitfalls of oblique lateral interbody fusion: a comprehensive narrative review. Neurospine 2022;19:163–76.
crossref pmid pmc pdf
112. Park MK, Park SA, Son SK, Park WW, Choi SH. Clinical and radiological outcomes of unilateral biportal endoscopic lumbar interbody fusion (ULIF) compared with conventional posterior lumbar interbody fusion (PLIF): 1-year follow-up. Neurosurg Rev 2019;42:753–61.
crossref pmid pdf
113. Li Y, Gao SJ, Hu X, Lin SS. Comparison of efficacy between unilateral biportal endoscopic lumbar fusion versus minimally invasive transforaminal lumbar fusion in the treatment of lumbar degenerative diseases: a systematic review and meta-analysis. Medicine (Baltimore) 2023;102:e34705.
crossref pmid pmc
114. Yu Q, Lu HG, Pan XK, Shen ZH, Ren P, Hu XQ. Unilateral biportal endoscopic transforaminal lumbar interbody fusion versus conventional interbody fusion for the treatment of degenerative lumbar spine disease: a systematic review and meta-analysis. BMC Musculoskelet Disord 2023;24:838.
crossref pmid pmc pdf
115. Wu PH, Kim HS, An JW, et al. Prospective cohort study with a 2-year follow-up of clinical results, fusion rate, and muscle bulk for uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion. Asian Spine J 2023;17:373–81.
crossref pmid pmc pdf
116. Kim JE, Son S, Park EJ. Technical feasibility and early clinical outcome of biportal endoscopic transforaminal lumbar interbody fusion using larger cage. World Neurosurg 2023;178:e666–72.
crossref pmid
117. Frisch RF, Luna IY, Brooks DM, Joshua G, O’Brien JR. Clinical and radiographic analysis of expandable versus static lateral lumbar interbody fusion devices with two-year follow-up. J Spine Surg 2018;4:62–71.
crossref pmid pmc
118. Macki M, Hamilton T, Haddad YW, Chang V. Expandable cage technology: transforaminal, anterior, and lateral lumbar interbody fusion. Oper Neurosurg (Hagerstown) 2021;21(Suppl 1): S69–80.
crossref pmid pdf
119. Kim CW, Doerr TM, Luna IY, et al. Minimally invasive transforaminal lumbar interbody fusion using expandable technology: a clinical and radiographic analysis of 50 patients. World Neurosurg 2016;90:228–35.
crossref pmid
120. Hawasli AH, Khalifeh JM, Chatrath A, Yarbrough CK, Ray WZ. Minimally invasive transforaminal lumbar interbody fusion with expandable versus static interbody devices: radiographic assessment of sagittal segmental and pelvic parameters. Neurosurg Focus 2017;43:E10.
crossref
121. Chang CC, Chou D, Pennicooke B, et al. Long-term radiographic outcomes of expandable versus static cages in transforaminal lumbar interbody fusion. J Neurosurg Spine 2020;34:471–80.
crossref pmid
122. Vaishnav AS, Saville P, McAnany S, et al. Retrospective review of immediate restoration of lordosis in single-level minimally invasive transforaminal lumbar interbody fusion: a comparison of static and expandable interbody cages. Oper Neurosurg (Hagerstown) 2020;18:518–23.
crossref pmid pdf
123. Woodward J, Koro L, Richards D, Keegan C, Fessler RD, Fessler RG. Expandable versus static transforaminal lumbar interbody fusion cages: 1-year radiographic parameters and patient-reported outcomes. World Neurosurg 2022;159:e1–7.
crossref pmid
124. Ledesma JA, Lambrechts MJ, Dees A, et al. Static versus expandable interbody fusion devices: a comparison of 1-year clinical and radiographic outcomes in minimally invasive transforaminal lumbar interbody fusion. Asian Spine J 2023;17:61–74.
crossref pmid pmc pdf
125. Calvachi-Prieto P, McAvoy MB, Cerecedo-Lopez CD, et al. Expandable versus static cages in minimally invasive lumbar interbody fusion: a systematic review and meta-analysis. World Neurosurg 2021;151:e607–14.
crossref pmid
126. Su YH, Wu PK, Wu MH, Wong KW, Li WW, Chou SH. Comparison of the radiographic and clinical outcomes between expandable cage and static cage for transforaminal lumbar interbody fusion: a systematic review and meta-analysis. World Neurosurg 2023;179:133–42.
crossref pmid
127. Lin GX, Kim JS, Kotheeranurak V, Chen CM, Hu BS, Rui G. Does the application of expandable cages in TLIF provide improved clinical and radiological results compared to static cages?: a meta-analysis. Front Surg 2022;9:949938.
crossref pmid pmc
128. Lee S, Kim JG, Kim HJ. Comparison of surgical outcomes between lumbar interbody fusions using expandable and static cages: a systematic review and meta-analysis. Spine J 2023;23:1593–601.
crossref pmid
129. Kwon BK, Berta S, Daffner SD, et al. Radiographic analysis of transforaminal lumbar interbody fusion for the treatment of adult isthmic spondylolisthesis. J Spinal Disord Tech 2003;16:469–76.
crossref pmid
130. Elias WJ, Simmons NE, Kaptain GJ, Chadduck JB, Whitehill R. Complications of posterior lumbar interbody fusion when using a titanium threaded cage device. J Neurosurg 2000;93(1 Suppl): 45–52.
crossref pmid
131. Li YM, Frisch RF, Huang Z, et al. Comparative effectiveness of laterally placed expandable versus static interbody spacers: a 1-year follow-up radiographic and clinical outcomes study. Asian Spine J 2021;15:89–96.
crossref pmid pmc pdf
132. Li YM, Frisch RF, Huang Z, et al. Comparative effectiveness of expandable versus static interbody spacers via MIS LLIF: a 2-year radiographic and clinical outcomes study. Global Spine J 2020;10:998–1005.
crossref pmid pmc pdf
133. Daculsi G, Fellah BH, Miramond T, Durand M. Osteoconduction, osteogenicity, osteoinduction, what are the fundamental properties for a smart bone substitutes. Ing Rech Biomed 2013;34:346–8.
crossref
134. Cha M, Jin YZ, Park JW, et al. Three-dimensional printed polylactic acid scaffold integrated with BMP-2 laden hydrogel for precise bone regeneration. Biomater Res 2021;25:35.
crossref pmid pmc pdf
135. Lu X, Wu Z, Xu K, et al. Multifunctional coatings of titanium implants toward promoting osseointegration and preventing infection: recent developments. Front Bioeng Biotechnol 2021;9:783816.
crossref pmid pmc
TOOLS
Share :
Facebook Twitter Linked In Google+ Line it
METRICS Graph View
  • 3 Web of Science
  • 3 Crossref
  •   Scopus
  • 2,284 View
  • 328 Download
Related articles in ASJ

Diagnosing Cervical Fusion: A Comprehensive Literature Review2008 December;2(2)



ABOUT
ARTICLE CATEGORY

Browse all articles >

BROWSE ARTICLES
EDITORIAL POLICY
FOR CONTRIBUTORS
Editorial Office
Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine
88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea
Tel: +82-2-3010-3530    Fax: +82-2-3010-8555    E-mail: asianspinejournal@gmail.com                
Korean Society of Spine Surgery
27, Dongguk-ro, Ilsandong-gu, Goyang-si 10326, Korea
Tel: +82-31-966-3413    Fax: +82-2-831-3414    E-mail: office@spine.or.kr                

Copyright © 2024 by Korean Society of Spine Surgery.

Developed in M2PI

Close layer
prev next