Abstract
Purpose
This study aimed to establish a novel classification system for lumbar intervertebral spaces based on anatomical morphology, to investigate the relationship between intervertebral space types and cage migration risk after transforaminal lumbar interbody fusion (TLIF), and to optimize fusion strategies tailored to different anatomical types.
Methods
A retrospective cohort study was conducted on 103 patients who underwent TLIF between February 2022 and June 2023. Lumbar intervertebral spaces were classified into 3 fundamental types: lordotic, neutral and kyphotic and 2 modified types: normal and degenerative. Clinical outcomes (Visual Analogue Scale [VAS], Oswestry Disability Index [ODI]), and radiographic parameters (Intervertebral Space Angle [ISA], Intervertebral Space Height [ISH], Intervertebral Foramen Height [IFH]) were evaluated. Statistical analyses included t tests, ANOVA, chi-square tests, and logistic regression.
Results
VAS and ODI scores significantly improved postoperatively (P < 0.05). ISA, ISH, and IFH showed significant postoperative increases across all fundamental types. Cage migration occurred in 8 segments, predominantly in degenerative-type intervertebral spaces. Logistic regression revealed that the degenerative type was associated with a 17-fold increased risk of cage migration (OR = 17.02). No significant association was found between fundamental type and migration. Fusion rates exceeded 98% across all groups.
Conclusion
The novel classification of lumbar intervertebral spaces effectively predicts cage migration risk. The degenerative modified type is a strong risk factor for migration. Tailoring surgical strategies to intervertebral space morphology may improve stability and outcomes in lumbar interbody fusion procedures.
Keywords: Lumbar interbody fusion, Cage migration, Intervertebral space classification, Degenerative endplate, Transforaminal lumbar interbody fusion (TLIF)
Introduction
Lumbar Interbody Fusion (LIF) is a common spinal surgery performed to treat various lumbar disorders such as intervertebral disc herniation, degenerative disc disease, spinal instability, lumbar spondylolisthesis, and scoliosis [1, 2]. The interbody cage plays a critical role in maintaining disc height, promoting fusion, and restoring stability during LIF [1, 3]. However, cage migration can compromise spinal biomechanical stability and interbody fusion, leading to complications such as nerve compression, adjacent endplate damage, or infection in the fusion area [4–6].
Previous studies have demonstrated that cage migration is associated with factors such as cage design, material, implantation orientation, and endplate damage [1, 7]. However, there is a lack of research on the influence of intervertebral disc anatomy on cage migration. In this study, a novel clinical classification of lumbar intervertebral spaces based on their anatomical morphology was proposed, and its relationship with cage migration was investigated. Furthermore, modifications to interbody fusion techniques were suggested to minimize the occurrence of cage migration postoperatively.
Methods
This retrospective study was conducted with approval from our hospital’s institutional review board. Preoperative informed consent was obtained from all eligible patients. The study included patients diagnosed with multilevel lumbar degenerative diseases who underwent TLIF in our department between February 2022 and June 2023. Inclusion criteria for the study were as follows: (1) presence of neurogenic claudication symptoms, such as pain, tingling, or cramping in the lower back and/or legs, hips, and buttocks, potentially accompanied by leg weakness or heaviness; (2) persistence of symptoms without improvement following at least three months of conservative treatment; (3) no more than four levels involved based on imaging studies; (4) age between 18 and 80 years and (5) a minimum follow-up period of one year for all participants.
Exclusion criteria were defined as follows: (1) prior history of spinal fractures or surgical procedures; (2) congenital spinal abnormalities, tumors, tuberculosis, or metabolic bone conditions; (3) coexisting neurological disorders, including Parkinson’s disease or Alzheimer’s dementia; (4) severe diabetes or other untreated metabolic conditions; (5) a history of psychiatric illness; (6) past alcoholism or substance abuse; and (7) any severe systemic illness, such as heart failure or HIV infection.
Lumbar intervertebral space classification (LISC)
Intervertebral space angle (ISA) is defined as the angle measured between the upper and lower endplates of the intervertebral space. The specific measurement method is as follows: on a lateral X-ray view, lines are drawn along the lower endplate of the upper vertebra and the upper endplate of the lower vertebra. The angle between these two lines is measured as the ISA. If the lines intersect posterior to the intervertebral space, the ISA is positive. If they intersect anterior to the intervertebral space, the ISA is negative. If the lines are parallel or nearly so, the ISA approaches zero.
The LISC is divided into two levels: fundamental type and modified type (Fig. 1, 2). The fundamental type is quantified based on the intersegmental angle (ISA), while the modified type is categorized according to the anatomical morphology of the intervertebral space.
Fig. 1.
Illustration of the fundamental type of intervertebral spaces classification. Lordotic type: ISA > 5°, wider anteriorly, reflecting normal lordosis (a). Neutral type: 5° ≤ ISA ≤ 5°, flat intervertebral space (b). Kyphotic type: ISA < − 5°, wider posteriorly, typical of kyphotic deformities (c). ISH: Mean height of anterior and posterior disc spaces. IFH: Vertical distance between pedicle margins. ISA: Angle between upper and lower endplates, classifying fundamental types
Fig. 2.
Illustration of the modified type of intervertebral spaces classification. Normal type: both endplates are smooth, regular, and maintain uniform disc height, reflecting healthy intervertebral space morphology (a). Degenerative type: includes two scenarios–one where one endplate is degenerated and the other is normal, and another where both endplates are degenerated. Both participants exhibit varying degrees of endplate irregularities and disc height reduction, indicative of intervertebral space degeneration (b/c)
The fundamental types include the following three subtypes: (1) lordotic type (ISA > 5°): indicates a wider anterior and narrower posterior intervertebral space, typically reflecting the physiological lordosis of the disc space. (2) neutral type (− 5° ≤ ISA ≤ 5°): suggests a flattened curvature of the intervertebral space. (3) kyphotic type (ISA < − 5°): indicates a wider posterior and narrower anterior intervertebral space, commonly seen in patients with kyphotic deformities of the lumbar spine.
The modified type includes two subtypes: (1) normal: a normal endplate appears as a smooth, continuous, and thin line on radiographic imaging, reflecting the structural integrity of the vertebral endplate and adjacent cartilage. Its contour is regular, with a gentle curve or slight flatness, and it maintains clear boundaries with the vertebral body. The bone density is uniform without any evidence of sclerosis, lucent areas, or irregularities. The intervertebral disc space remains at a normal height, symmetrical, and free of collapse or narrowing, indicating the absence of degenerative changes. A normal endplate signifies healthy load distribution and structural stability within the lumbar spine. (2) degenerative: a degenerative endplate exhibits irregularities in shape, contour, and density, often caused by intervertebral disc degeneration and mechanical stress over time. On radiographic imaging, it may appear wavy, undulating, or thickened, with areas of sclerosis showing increased bone density or lucent zones indicating subchondral bone weakening or cystic changes. The intervertebral disc space is often reduced in height, asymmetric, or collapsed, reflecting significant degeneration. Marginal changes such as osteophyte formation and irregular bone edges may also be present. These findings indicate compromised endplate integrity and are frequently associated with lumbar degenerative diseases, such as disc herniation or spinal stenosis.
Surgical technique
The surgical procedures of TLIF have been well described by previous literatures [8–10]. The patient was placed in a prone position after general anesthesia. A posterior midline incision is made over the lumbar spine and the paraspinal muscles are detached from the spinous process, lamina, facet capsules and the transverse processes. A uni- or bilateral inferior facetectomy is performed followed by superior facet resection, discectomy, interbody cage (Double Medical Technology Inc, China) implantation, and pedicle screw placement. For lordotic intervertebral spaces, posterior compression is not required after the insertion of the fusion cage. For neutral and kyphotic intervertebral spaces, posterior compression is routinely performed. After the operation, hemostasis, irrigation, placement of negative pressure drainage tube and suture were performed. All patients received prophylactic intravenous antibiotics (cefazolin 1.0 g every 12 h for 24–48 h), were mobilized with a waist support brace from the second postoperative day and wore the brace for 8–12 weeks. Nutritional support was provided as needed. Rehabilitation training was started under physiotherapist supervision, beginning with isometric limb/core exercises in the first week and progressing to walking and lumbar stabilization after 4–6 weeks.
Clinical evaluation
Intra-operative blood loss as well as operative time was recorded. The Visual Analogue Scale (VAS) scores and Oswestry Disability Index (ODI) were recorded in the preoperative period and at every follow-up visit. Data on fusion rates and prosthesis-related complications, such as migration or subsidence at each fusion level, were also collected. Follow-ups were conducted on the first postoperative day, at 3 and 6 months, and then every 6 months thereafter. During each follow-up, patients underwent imaging evaluations and completed a standardized assessment questionnaire.
Imaging analysis
(1) Intervertebral space height (ISH): the mean of anterior and posterior ISH; (2) Intervertebral foramen height (IFH): the distance between the lower margin of the superior pedicle and vertebral body connection and the upper margin of the inferior pedicle and vertebral body connection; (3) Bone graft fusion was evaluated according to the criterion reported by Bridwell et al. [11]. To correct the intra-observer and inter-observer reliability of the radiological measurements, three experienced observers were assigned to independently evaluate the radiographs of the patients. Each of them took measurements three times, and the mean values were used for statistical analysis.
Cage-related complications
The cage migration and subsidence were evaluated in each fusion level according to the radiological examinations at each follow-up time point. Cage migration was defined as the posterior movement of the cage past the posterior wall of the vertebral body. Correct initial positioning of the cages immediately postoperatively was confirmed by plain X-ray, whereas postoperative cage migration was determined by CT scan as well as plain films [2, 12]. Cage subsidence was evaluated using lateral radiographs and was defined as more than 2-mm migration of the cage into the adjacent vertebral body [13, 14].
Statistical analysis
To determine whether there were significant differences in postoperative outcomes among the groups, an independent sample t test or Wilcoxon rank-sum test was utilized. Two-way analysis of variance (ANOVA) is used to evaluate the independent and interaction effects of two categorical factors on a continuous variable. When a significant main effect is identified in the two-way ANOVA, Tukey HSD test is employed for post hoc comparisons to further analyze differences between groups. The chi-square test was employed to compare complication rates between the groups. Logistic regression analysis is applied to assess the independent impact of categorical variables on the occurrence of cage migration. All statistical analyses were conducted using the Statistical Package for Social Sciences (SPSS) software, version 26.0 (SPSS Inc., Chicago, IL). A p value of less than 0.05 was considered indicative of statistical significance.
Results
Patient demographics and surgical outcomes
A total of 118 participants were initially reviewed during the study period based on departmental records. After excluding 9 participants that did not meet the inclusion criteria and 6 participants lost to follow-up, 103 patients (mean age 54.25 ± 14.47 years; 56 men and 47 women) were included. The average follow-up duration was 12.1 ± 2.9 months. Among the included patients, 51 had lumbar disc herniation, 27 had lumbar spinal stenosis, and 25 had lumbar spondylolisthesis. The surgical levels included 59 participants with one level, 38 participants with two levels, 1 case with three levels, and 5 participants with four levels (Fig. 3), resulting in a total of 158 interbody fusion segments. These segments were categorized by LISC into 101 segments in the lordotic group, 52 in neutral group, and 5 in kyphotic group.
Fig. 3.
a–f: Preoperative and postoperative imaging of a 78-year-old male patient diagnosed with lumbar spinal stenosis (a, b). Postoperative lateral X-rays following the initial L2-S1 posterior fixation and fusion surgery, showing proper placement of pedicle screws and rods (c, d). CT scans at 3 months post-surgery reveal right-sided L5-S1 cage displacement, correlating with the patient’s recurrence of right lower limb pain and numbness (e). Pre-revision MRI confirms cage migration and highlights lumbar spinal changes (f). Post-revision lateral X-ray after repositioning and securing the L5-S1 cage, demonstrating stable fixation. The patient fully recovered with complete resolution of symptoms following the revision surgery
At the L2/3 level, there were 1 case of the degenerative type and 4 participants of the normal type. At the L3/4 level, there were 4 participants of the degenerative type and 18 participants of the normal type. At the L4/5 level, there were 17 participants of the degenerative type and 61 participants of the normal type. At the L5/S1 level, there were 10 participants of the degenerative type and 43 participants of the normal type. Overall, there were 126 participants of the normal type and 32 participants of the degenerative type.
The mean surgery duration was 143.1 ± 24.3 min, and the average blood loss was 339.81 ± 147.75 ml. Both VAS and ODI scores showed significant improvement at the final follow-up. VAS scores decreased from 6.22 ± 1.05 preoperatively to 1.32 ± 0.48 (P < 0.05), while ODI scores dropped from 46.83 ± 12.92 to 13.04 ± 1.75 (P < 0.05, Table 1).
Table 1.
Patient demographics and surgical characteristics
| Characteristic | Values |
|---|---|
| Number of patients | 103 |
| Age (years, mean ± SD) | 54.25 ± 14.47 |
| Gender (male/female) | 56/47 |
| Follow-up period (months, mean ± SD) | 12.1 ± 2.9 |
| Total number of segments | 158 |
| Surgical segments (L2/3) | 5 |
| Surgical segments (L3/4) | 22 |
| Surgical segments (L4/5) | 78 |
| Surgical segments (L5/S1) | 53 |
| Fundamental types (Lordotic/Neutral/Kyphotic) | 101/52/5 |
| Modified types (normal/degenerative) | 126/32 |
| Surgical time (min, mean ± SD) | 143.1 ± 24.3 |
| Intraoperative blood loss (mL, mean ± SD) | 339.81 ± 147.75 |
| VAS score (Preoperative, mean ± SD) | 6.22 ± 1.05 |
| VAS score (Final follow-up, mean ± SD) | 1.32 ± 0.48 |
| ODI score (Preoperative, mean ± SD) | 46.83 ± 12.92 |
| ODI score (Final follow-up, mean ± SD) | 13.04 ± 1.75 |
VAS = Visual Analogue Scale, ODI = Oswestry Disability Index, SD = Standard Deviation
Radiographic results
In lordotic group, the ISA improved significantly from 11.41 ± 3.81° to 11.43 ± 3.74° at the final follow-up (P > 0.05, Table 2). Similarly, neutral group showed a notable increase in ISA from 2.02 ± 2.38° to 8.35 ± 3.50° (P < 0.05). In kyphotic group, the ISA rose significantly from − 7.5 ± 2.12° to 8 ± 7.07° (P < 0.05). Similarly, the IFH values increased from 9.13 ± 1.04 mm to 16.12 ± 1.29 mm (P < 0.05) in lordotic group, from 12.13 ± 1.49 mm to 17.93 ± 1.32 mm (P < 0.05) in neutral group, and from 13.27 ± 1.58 mm to 15.34 ± 1.09 mm (P < 0.05) in kyphotic group. For ISH, lordotic group increased from 8.82 ± 2.22 mm to 11.13 ± 2.04 mm (P < 0.05), neutral group from 7.01 ± 2.04 mm to 10.31 ± 1.96 mm (P < 0.05), and kyphotic group from 5.8 ± 0.71 mm to 10.05 ± 3.89 mm (P < 0.05).
Table 2.
Radiographic evaluation by fundamental type
| Characteristic | Lordotic | Neutral | Kyphotic |
|---|---|---|---|
| Preoperative ISA (°) | 11.41 ± 3.81 | 2.02 ± 2.38 | −7.5 ± 2.12 |
| Final follow-up ISA (°) | 11.43 ± 3.74 | 8.35 ± 3.50 | 8 ± 7.07 |
| P-Value (within-group, ISA) | > 0.05 | < 0.05 | < 0.05 |
| P-value (comparison) | Lordotic vs neutral: < 0.05 | Neutral vs kyphotic: < 0.05 | Lordotic vs kyphotic: < 0.05 |
| Preoperative IFH (mm) | 9.13 ± 1.04 | 12.13 ± 1.49 | 13.27 ± 1.58 |
| Final follow-up IFH (mm) | 16.12 ± 1.29 | 17.93 ± 1.32 | 15.34 ± 1.09 |
| P-Value (within-group, IFH) | < 0.05 | < 0.05 | < 0.05 |
| P-value (comparison) | Lordotic vs neutral: < 0.05 | Neutral vs kyphotic: < 0.05 | Lordotic vs kyphotic: < 0.05 |
| Preoperative ISH (mm) | 8.82 ± 2.22 | 7.01 ± 2.04 | 5.8 ± 0.71 |
| Final follow-up ISH (mm) | 11.13 ± 2.04 | 10.31 ± 1.96 | 10.05 ± 3.89 |
| P-Value (within-group, ISH) | < 0.05 | < 0.05 | < 0.05 |
| P-value (comparison) | Lordotic vs neutral: > 0.05 | Neutral vs kyphotic: > 0.05 | Lordotic vs kyphotic: > 0.05 |
| Bone Fusion Rate (%) | 100% | 98.2% | 100% |
| P-value (comparison) | Lordotic vs neutral: > 0.05 | Neutral vs kyphotic: > 0.05 | Lordotic vs kyphotic: > 0.05 |
ISA = Intervertebral Space Angle, IFH = Intervertebral Foramen Height, ISH = Intervertebral Space Height
The two-way ANOVA results showed that the main effects of the fundamental types on ISA and IFH changes were statistically significant (P < 0.05), while the main effect of the modified types and the interaction between fundamental and modified types were not significant (P > 0.05). In addition, the main effects of both the fundamental type and the modified type on ISH changes showed no significant differences (P > 0.05). Post hoc multiple comparisons (Tukey HSD test) revealed that the ISA and IFH changes in the lordotic group showed statistically significant differences compared to the neutral and kyphotic groups (P < 0.05). In addition, there was also a significant difference of changes between the neutral and kyphotic groups (P < 0.05). The fusion rates for lordotic, neutral and kyphotic groups were 100%, 98.2%, and 100%, respectively, at the final follow-up (Table 3). Chi-square test results indicated that neither the modified type nor the fundamental type showed a significant association with the bone fusion rate (P > 0.05).
Table 3.
Cage migration by fundamental and modified types
| Characteristic | Lordotic | Neutral | Kyphotic | Normal | Degenerative |
|---|---|---|---|---|---|
| Total participants | 101 | 52 | 5 | 126 | 32 |
| Participants with migration | 6 | 2 | 0 | 1 | 7 |
| Migration rate (%) | 5.94 | 3.85 | 0 | 0.7 | 21.88 |
| P-value (Comparison) | Lordotic vs neutral: > 0.05 | Neutral vs kyphotic: > 0.05 | Lordotic vs kyphotic: > 0.05 | Normal vs degenerative: < 0.05 | N/A |
N/A = Not Applicable
Cage-related complications
The lordotic group had 6 participants (5.94%) of prosthesis migration, while neutral group had 2 participants (3.64%) of prosthesis migration. No instances of prosthesis migration were reported in the kyphotic group. Among all 8 participants of displacement, 1 case was classified as normal type, and 7 participants were classified as degenerative type. The Fisher’s exact test results indicated that fusion cage displacement was significantly associated with the modified types (P < 0.05), whereas no significant association was observed with the fundamental types (P > 0.05).
Using regularized logistic regression models (Lasso and Ridge), we evaluated the impact of modified type and fundamental type on the risk of cage migration. The intervertebral space of degenerative type significantly increased the risk of cage migration, with an odds ratio of approximately 17 compared to the ones of normal type (Lasso model, OR = 17.02). This result was confirmed in the Ridge model, showing consistent odds ratios (≈17). In the Lasso model, all fundamental type categories (lordotic, neutral, kyphotic) were excluded, indicating a minimal impact on cage migration risk. The Ridge model retained these variables, but their coefficients were small and statistically insignificant, further supporting the limited influence of fundamental type. All participants with cage migration underwent secondary surgical treatment and showed good recovery at the final follow-up. No case with prosthetic subsidence occurred in our series.
Discussion
In this study, we established a novel radiographic classification system of lumbar intervertebral spaces and evaluated its predictive value for cage-related complications after TLIF. The major finding was that the modified type, particularly the degenerative endplate morphology, was strongly associated with cage migration, showing an approximately 17-fold increased risk compared with the normal type. In contrast, the fundamental types (lordotic, neutral, kyphotic) primarily influenced radiographic restoration parameters such as ISA and IFH, but had no independent effect on migration risk.
Previous reports have shown that cage migration is influenced by cage design, implantation orientation, and endplate preparation [15–18]. Our results add to this body of evidence by demonstrating that endplate degeneration itself, reflected by our modified classification, is a key risk factor. This finding is in line with recent studies highlighting that irregular endplate morphology can compromise implant stability and lead to subsidence or migration. Unlike earlier classifications that only focused on angular measurements, our system integrates both segmental angle and endplate quality, thereby providing a more comprehensive evaluation of disc space morphology.
There are several biomechanical explanations for the higher migration risk in degenerative types: (1) reduced contact area between the cage and the endplate limits frictional stability; (2) excessive endplate preparation may be required to fit irregular spaces, predisposing to damage; (3) uneven stress distribution leads to localized overload and cage displacement. Clinically, these mechanisms suggest that careful preoperative assessment and intraoperative cage selection are critical in degenerative spaces. For example, larger or crescent-shaped cages may provide better adaptation and stability [19, 20]. Enhanced postoperative monitoring is also recommended for early detection of migration.
The strengths of our study include the introduction of a practical classification system with direct clinical applicability, and the use of logistic regression models (Lasso and Ridge) to confirm the independent effect of degenerative morphology. However, several limitations must be acknowledged. Cage-related complications remain relatively rare (3–4%), and only eight migration participants were observed. This small number of events reduces the statistical power of our conclusions, and larger multicenter cohorts with longer follow-up are needed. Additionally, posterior compression was not routinely applied in the lordotic group, which may have confounded migration risk. Although our regression analysis showed no independent association with fundamental type, future studies with standardized procedures are warranted. Finally, bone mineral density (BMD) was not quantitatively assessed in all patients. Although severe osteoporosis was excluded, the contribution of undiagnosed osteoporosis or osteopenia cannot be ruled out. Incorporating DXA or CT-based BMD measurements would strengthen future analyses.
Moreover, other surrounding spinal structures, particularly the paraspinal muscles, may also influence fusion stability. Recent evidence indicates that fatty infiltration of the multifidus muscle predicts screw loosening after short-segment fusion [21]. While our study was limited to intervertebral space morphology, integrating muscle quality and facet joint condition into future analyses may provide a more comprehensive assessment of fusion outcomes.
In summary, our findings indicate that degenerative endplate morphology is a major risk factor for cage migration, while fundamental disc space angles mainly affect radiographic correction. The proposed classification system may help surgeons stratify patients preoperatively and tailor surgical strategies accordingly. Future studies should validate this system in larger, multi-institutional cohorts, and explore advanced implant designs or augmented fixation techniques specifically suited for degenerative disc spaces.
Author contributions
Y.H. and L.L. conceived the study, designed the methodology, and wrote the main manuscript text. T.Z. collected and analyzed clinical and radiological data. J.G.S. supervised the project, critically revised the manuscript, and provided surgical guidance. Y.F.G. was responsible for coordinating the revision process, addressing reviewer comments, and making substantial contributions to the manuscript’s editing and refinement. All authors reviewed and approved the final manuscript.
Funding
This study was supported by the Shanghai municipal health commission, general program (grant no. 202340128).
Data availability
No datasets were generated or analysed during the current study.
Declarations
Ethics approval and consent to participate
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Yang Hou and Lei Liu have contributed equally to this study and should be considered as co-first authors.
Contributor Information
Yongfei Guo, Email: Junjiespine@sina.com.
Jiangang Shi, Email: Alexzandersuper@163.com.
References
- 1.Zhu K, Yan S, Guo S, Tong J, Li C, Tan J, et al. Morphological changes of contralateral intervertebral foramen induced by cage insertion orientation after unilateral transforaminal lumbar interbody fusion. J Orthop Surg Res. 2019;14(1):79. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Hou Y, Shi H, Zhao T, Shi H, Shi J, Shi G. A retrospective study on application of a classification criterion based on relative intervertebral tension in spinal fusion surgery for lumbar degenerative diseases. BMC Surg. 2023;23(1):77. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Williams AL, Gornet MF, Burkus JK. CT evaluation of lumbar interbody fusion: current concepts. AJNR Am J Neuroradiol. 2005;26(8):2057–66. [PMC free article] [PubMed] [Google Scholar]
- 4.Ropper AE. Commentary on “Mini-Open intercostal retroperitoneal approach for upper lumbar spine lateral interbody fusion.” Neurospine. 2023;20(2):564–6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.He J, Luo F, Fang Q, Xu J, Zhang Z. Reverse lumbar pedicle screw in oblique lateral interbody fusion: a novel concept to restrict cage subsidence. Orthop Surg. 2023;15(12):3193–201. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Hacker RJ. The Ray threaded fusion cage for posterior lumbar interbody fusion. Neurosurgery. 1998. 10.1097/00006123-199810000-00163. [DOI] [PubMed] [Google Scholar]
- 7.Hou Y, Shi H, Shi H, Zhao T, Shi J, Shi G. A meta-analysis of risk factors for cage migration after lumbar fusion surgery. World Neurosurg: X. 2023;18:100152. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Kaiser MG, Eck JC, Groff MW, Watters WC 3rd, Dailey AT, Resnick DK, et al. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 1: introduction and methodology. J Neurosurg Spine. 2014;21(1):2–6. [DOI] [PubMed] [Google Scholar]
- 9.Hou Y, Zhao T, Liu X, Shi J, Shi G. A novel technology named as selective fenestration and axial decompression for the surgical management of lumbar degenerative diseases. Interdiscip Neurosurg. 2023. 10.1016/j.inat.2023.101798. [Google Scholar]
- 10.Hou Y, Shi H, Shi H, Zhao T, Shi J, Shi G. The clinical effectiveness and complications of lumbar selective fenestration and concave-side fusion (LSFCF) in degenerative lumbar scoliosis (DLS) combined with lumbar spinal stenosis (LSS). BMC Surg. 2022;22(1):405. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Bridwell KH, Lenke LG, McEnery KW, Baldus C, Blanke K. Anterior fresh frozen structural allografts in the thoracic and lumbar spine: do they work if combined with posterior fusion and instrumentation in adult patients with kyphosis or anterior column defects? Spine. 1995;20(12):1410–8. [PubMed] [Google Scholar]
- 12.Duncan JW, Bailey RA. An analysis of fusion cage migration in unilateral and bilateral fixation with transforaminal lumbar interbody fusion. Eur Spine J. 2013;22(2):439–45. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Kim M-c, Chung H-T, Cho JL, Kim D-j, Chung N-S. Subsidence of polyetheretherketone cage after minimally invasive transforaminal lumbar interbody fusion. J Spinal Disord Tech. 2013;26:87–92. [DOI] [PubMed] [Google Scholar]
- 14.Yao YC, Chou PH, Lin HH, Wang ST, Liu CL, Chang MC. Risk factors of cage subsidence in patients received minimally invasive transforaminal lumbar interbody fusion. Spine. 2020;45(19):E1279–85. [DOI] [PubMed] [Google Scholar]
- 15.Kimura H, Shikata J, Odate S, Soeda T, Yamamura S. Risk factors for cage retropulsion after posterior lumbar interbody fusion: analysis of 1070 cases. Spine. 2012;37(13):1164–9. [DOI] [PubMed] [Google Scholar]
- 16.Pan FM, Wang SJ, Yong ZY, Liu XM, Huang YF, Wu DS. Risk factors for cage retropulsion after lumbar interbody fusion surgery: series of cases and literature review. Int J Surg. 2016;30:56–62. [DOI] [PubMed] [Google Scholar]
- 17.Peng L, Guo J, Lu JP, Jin S, Wang P, Shen HY. Risk factors and scoring system of cage retropulsion after posterior lumbar interbody fusion: a retrospective observational study. Orthop Surg. 2021;13(3):855–62. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Stergar J, Gradisnik L, Velnar T, Maver U. Intervertebral disc tissue engineering: a brief review. Bosn J Basic Med Sci. 2019;19(2):130–7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Wanderman N, Sebastian A, Fredericks DR Jr., Slaven SE, Helgeson MD. Bullet cage versus crescent cage design in transforaminal lumbar interbody fusion. Clin Spine Surg. 2020;33(2):47–9. [DOI] [PubMed] [Google Scholar]
- 20.Comer GC, Behn A, Ravi S, Cheng I. A biomechanical comparison of shape design and positioning of transforaminal lumbar interbody fusion cages. Glob Spine J. 2015;6(5):432–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Ekşi M, Topçu A, Topaloğlu F, Tanriverdi N, Yeşilyurt SC, Duymaz UC, et al. Fatty infiltration in the multifidus predicts screw-loosening following short-segment decompression and fusion: proof of why we should protect and rehabilitate the paraspinal muscles. Eur Spine J. 2025;34(6):2427–37. [DOI] [PubMed] [Google Scholar]
Associated Data
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Data Availability Statement
No datasets were generated or analysed during the current study.