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Spinopelvic parameters and functional outcomes following posterior lumbar interbody fusion with polyetheretherketone cage implantation for adult lumbar spondylolisthesis
*Corresponding author: Moaaz A. Hamoud, Department of Orthopaedics and Traumatology, Kafrelsheikh University Hospitals, Kafrelsheikh, Egypt. moaaz.aly.4.4@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Basiony M, Hamoud MA, Ramadan MO, Elgohary H, Hamed H, Gad H. Spinopelvic parameters and functional outcomes following posterior lumbar interbody fusion with polyetheretherketone cage implantation for adult lumbar spondylolisthesis. J Musculoskelet Surg Res. 2026;10:531-7. doi: 10.25259/JMSR_162_2026
Abstract
Objectives:
In the surgical treatment of lumbar spondylolisthesis (LS) with posterior lumbar interbody fusion (PLIF), interbody fusion cages play a vital role in supporting the vertebral body, restoring disc height, facilitating fusion, and correcting sagittal alignment. The objective of this study was to detect the effect of cage implantation on sagittal parameters and functional outcomes in patients undergoing PLIF surgery for LS.
Methods:
This retrospective cohort study included 120 patients who had undergone open PLIF surgery. Radiological outcome was evaluated using plain radiographs postoperatively and at 6 weeks, 3 months, 6 months, and 2 years. Functional outcome was assessed using the Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI) pre- and postoperatively.
Results:
This study included 120 patients (mean age 49.9 ± 7.0 years; 60.8% female; all single-level procedures: L4–L5 in 45.8%, L3–L4 in 27.5%, L5–S1 in 21.7%, and L2–L3 in 5.0%). Degenerative LS accounted for 63.3% of cases and isthmic LS for 36.7%. Mean operative time was 100.1 ± 18.0 min and mean blood loss was 493.5 ± 72.0 mL. The overall complication rate was 6.7% (8/120), with a reoperation rate of 1.7% (2/120). Satisfactory fusion (Bridwell grades I–II) was achieved in 86.7% of cases. The mean pre-operative ODI was 69.9 ± 6.2% and decreased significantly to 22.7 ± 4.5% at 2 years (p < 0.001; minimal clinically important difference met in 100%). The mean pre-operative VAS was 7.9 ± 0.6 and decreased significantly to 3.9 ± 0.5 (p < 0.001). Lumbar lordosis (LL) improved from 37.7 ± 5.0° to 54.2 ± 4.2° and pelvic incidence–LL mismatch decreased from 21.1 ± 5.3° to 4.8 ± 2.6° (both p < 0.001). The mean pre-operative sacral slope was 24.73, which increased significantly to 35.9 postoperatively. The mean pre-operative pelvic tilt was 34.73, which significantly decreased postoperatively to 22.77. The mean pre-operative pelvic incidence was 59.1, which did not significantly decrease to 59.07 postoperatively. The mean pre-operative LL was 37.7°, which increased significantly postoperatively to 54.17.
Conclusion:
The use of a cage in PLIF significantly enhances mechanical stability, fusion success, and functional recovery in adult LS.
Keywords
Intervertebral cage
Lumbar vertebrae
Posterior lumbar interbody fusion
Sagittal alignment
Spinal fusion
Spondylolisthesis
INTRODUCTION
Lumbar spondylolisthesis (LS) is often characterized by symptoms including persistent low back pain (LBP), radiating leg pain, and neurogenic intermittent claudication. While many patients react well to conservative therapy, a significant percentage require surgical intervention, with posterior lumbar interbody fusion (PLIF) becoming the most often utilized method in recent years.[1] Pedicle screw fixation provides immediate mechanical stability; however, long-term stability largely depends on the success of intervertebral fusion. The interbody cage is integral to achieving this goal. Technical mistakes in cage selection or positioning can ultimately disrupt fusion, thus leading to pedicle screw loosening, cage subsidence, and symptom recurrence, including back pain.[2] Moreover, cage implantation can affect post-operative sagittal alignment parameters that are hugely correlated with long-term functional results.[3]
In PLIF procedures for LS, the degenerated disc is removed as completely as possible, after which the interbody fusion cage is inserted into the disc space. Combined with a screw–rod construct, this configuration aims to restore spinal stability and normal physiological alignment. Wang et al. demonstrated that segmental instability together with suboptimal coronal alignment is closely linked to the clinical symptoms and functional decline observed in LS patients.[4] There is concern about examining the spine’s sagittal orientation. We now know that sagittal alignment directly affects a person’s energy expenditure.[5] The plumb line of the C7-sacrum lumbar lordosis (LL) and thoracic kyphosis is used to estimate sagittal alignment. Every person’s LL is influenced by their sacral slope (SS) and pelvic shape, two indicators of pelvic alignment. Thus, obtaining and maintaining adequate spinal stability and sagittal alignment during and after surgery is critical. Previous research suggests that interbody cage implantation increases the likelihood of firm fusion and aids in restoring LL.[6] Our work aimed at assessing how interbody cage implantation affects the sagittal alignment and functional results of adult LS patients undergoing PLIF.
MATERIALS AND METHODS
This retrospective cohort study reviewed 120 consecutive patients with LS treated at a tertiary university hospital between January 2022 and January 2024.
Selection criteria
Patients were identified from institutional records, and the study was conducted after ethical approval with written informed consent obtained from all patients and their families. The inclusion criteria were (1) confirmed indication for surgery (persistent symptoms after failed conservative treatment or pain interfering with daily activities, and significant or progressive neurological deficits). (2) Radiographic and magnetic resonance imaging-based diagnosis of LS, either Degenerative or isthmic. (3) All patients received PLIF with a polyetheretherketone (PEEK) cage. (4) The follow-up time was no <2 years, and all the relevant information was available. (5) All patients and their families signed informed consent forms and approved them by the medical ethics committee.
Exclusion criteria
(1) Vertebral fracture. (2) A history of previous spinal surgery or fractures. (3) Associated with spinal tumors or space-occupying lesions. (4) Pediatric and adolescent patients (age <18 years). (5) Adult degenerative spinal deformity or scoliosis (Cobb angle >20°).
Methods of assessment
Clinical
Disability using the Oswestry Disability Index (ODI)
LBP using the Visual Analog Scale (VAS).
Radiological
Plain radiograph: Anteroposterior, lateral standing position lumbosacral spine with dynamics (flexion and extension) showing both femurs superimposed on each other, measuring the following parameters:
Sacral slope (SS)
Pelvic incidence (PI)
Pelvic tilt (PT)
Lumbar lordosis (LL)
Pelvic incidence–LL (PI-LL)
Follow-up periods
Post-operative, 6 weeks, 3 months, 6 months, and 2 years.
Surgical technique
All procedures were performed through a standard open posterior midline approach under general anesthesia. No minimally invasive or tubular retractor techniques were employed in this cohort. Patients were placed prone on a radiolucent table; the operative field was disinfected and draped with waterproof towels. Through a posterior midline incision, bilateral paravertebral muscle dissection was performed to expose the lamina and facet joints at the index level. Sequential steps included laminectomy and foraminotomy for neural decompression, diskectomy with complete removal of the degenerated disc, thorough endplate preparation to expose cancellous bone, cage insertion (one or two PEEK cages filled with autograft), and bilateral pedicle screw-rod fixation to enhance stability and fusion.
Statistical analysis was performed using the software Statistical Package for the Social Sciences version 27. Categorical variables were described using their absolute frequencies and percentages. The Shapiro–Wilk test was used to assess the assumptions for parametric tests. To compare changes in a single variable between 2 time points within the same group, the paired sample t-test (for normally distributed data) was used. For variables that did not meet the normality assumption, the Wilcoxon signed-rank test was applied as a non-parametric alternative. The minimal clinically important difference (MCID) threshold was defined as ≥15 points for ODI and ≥1.5 points for VAS. Percentage change in outcome parameters was calculated as ([post-therapy value − baseline value] / baseline value × 100). The level of statistical significance was set at p < 0.05. A highly significant difference was present if p ≤ 0.001.
RESULTS
A total of 120 patients underwent single-level open PLIF with a PEEK cage during the study period. The cohort comprised 73 females (60.8%) and 47 males (39.2%), with a mean age of 49.9 ± 7.0 years (range, 32–62 years). Mean body mass index was 28.6 ± 3.9 kg/m2. Regarding comorbidities, hypertension was the most prevalent condition (46.7%), followed by diabetes mellitus (35.0%), smoking (27.5%), ischemic heart disease (15.0%), and osteoporosis (6.7%). With respect to pre-operative functional status, 56.7% of patients were classified as the American Society of Anesthesiologists (ASA) II, 28.3% as ASA I, and 15.0% as ASA III. Degenerative LS accounted for 76 cases (63.3%) and isthmic LS for 44 cases (36.7%). Meyerding grade I was the most common severity (50.8%), followed by grade II (40.0%) and grade III (9.2%). The most frequently operated level was L4–L5 (55 cases, 45.8%), followed by L3–L4 (33 cases, 27.5%), L5–S1 (26 cases, 21.7%), and L2–L3 (6 cases, 5.0%). A single cage was inserted in 104 patients (86.7%) and two cages in 16 patients (13.3%). All patients presented with LBP; sciatica was present in 80 patients (66.7%) and neurogenic claudication in 55 (45.8%) [Table 1].
| Variable | Category | n (%) or Mean±SD(%) | Range |
|---|---|---|---|
| Patient demographics | |||
| Age (years) | 49.9±7.0 | 32 – 62 | |
| Sex | Female | 73 (60.8) | |
| Male | 47 (39.2) | ||
| BMI (kg/m2) | 28.6±3.9 | 22.0 – 38.0 | |
| Comorbidities | |||
| Diabetes mellitus | 42 (35.0) | ||
| Hypertension | 56 (46.7) | ||
| Ischaemic heart disease | 18 (15.0) | ||
| Osteoporosis | 8 (6.7) | ||
| Smoking | 33 (27.5) | ||
| Activity Level | |||
| Level of activity | Sedentary | 53 (44.2) | |
| Moderate | 54 (45.0) | ||
| Active | 13 (10.8) | ||
| ASA physical status | |||
| ASA class | I | 34 (28.3) | |
| II | 68 (56.7) | ||
| III | 18 (15.0) | ||
| Spondylolisthesis classification | |||
| Meyerding grade | Grade I | 61 (50.8) | |
| Grade II | 48 (40.0) | ||
| Grade III | 11 (9.2) | ||
| Type | Degenerative | 76 (63.3) | |
| Isthmic | 44 (36.7) | ||
| Operative details and surgical level | |||
| Operative time (min) | 100.1±18.0 | 60 – 150 | |
| Blood loss (mL) | 493.5±72.0 | 350 – 700 | |
| Number of cages | 1 cage | 104 (86.7) | |
| 2 cages | 16 (13.3) | ||
| Spinal level | L4–L5 | 55 (45.8) | |
| L3–L4 | 33 (27.5) | ||
| L5–S1 | 26 (21.7) | ||
| L2–L3 | 6 (5.0) | ||
| Clinical presentation | |||
| Low back pain | 120 (100.0) | ||
| Sciatica | 80 (66.7) | ||
| Neurogenic claudication | 55 (45.8) | ||
Values are n (%) or mean±SD. ASA: American Society of Anesthesiologists, BMI: Body mass index, SD: Standard deviation
Perioperative data demonstrated a mean operative time of 100.1 ± 18.0 min (range, 60–150 min) and a mean estimated blood loss of 493.5 ± 72.0 mL (range, 350–700 mL). All 120 patients completed the full 2-year follow-up period; no cases were lost to follow-up. Regarding functional outcomes, the mean pre-operative ODI was 69.9 ± 6.2% (range 55–80%) and decreased significantly to 22.7 ± 4.5% (range 15–35%) at 2 years postoperatively, representing a mean reduction of 47.2% points (95% confidence interval [CI]: −48.1– −46.4; p < 0.001). The MCID for ODI was achieved in all 120 patients (100%). Similarly, the mean pre-operative VAS score was 7.9 ± 0.6 (range 7–9) and decreased significantly to 3.9 ± 0.5 (range 3–5) at 2 years (mean change −4.0, 95% CI: −4.2–−3.8; p < 0.001), with the MCID met in all patients (100%) [Table 2].
| Outcome | Pre-operative | Post-operative (2 yr) | Change (95% CI) | p-value | MCID Met(%) |
|---|---|---|---|---|---|
| ODI (%) | 69.9±6.2 (55–80) | 22.7±4.5 (15–35) | −47.2 (−48.1 to−46.4) | < 0.001 | 120/120 (100) |
| VAS | 7.9±0.6 (7–9) | 3.9±0.5 (3–5) | −4.0 (−4.2 to−3.8) | < 0.001 | 120/120 (100) |
| Sacral slope (°) | 24.7±2.2 (20–28) | 35.9±3.5 (30–45) | +11.2 (+10.6 to+11.8) | < 0.001 | N/A |
| Pelvic tilt (°) | 34.7±3.2 (28–41) | 22.8±3.2 (15–30) | −11.9 (−12.5 to−11.4) | < 0.001 | N/A |
| Pelvic incidence (°) | 59.1±3.8 (50–66) | 59.1±3.8 (50–66) | 0 (unchanged) | NS | N/A |
| Lumbar lordosis (°) | 37.7±3.5 (30–45) | 54.2±4.2 (45–65) | +16.5 (+15.8 to+17.2) | < 0.001 | N/A |
| PI–LL mismatch (°) | 21.1±5.3 (10–35) | 4.8±2.6 (0–10) | −16.3 (−17.1 to−15.5) | < 0.001 | N/A |
CI: Confidence interval, LL: Lumbar lordosis, MCID: Minimal clinically important difference, NS: Not significant, ODI: Oswestry Disability Index, PI: Pelvic incidence, PT: Pelvic tilt, SS: Sacral slope, VAS: Visual Analog Scale. Statistically significant at p<0.05. Highly significant at p≤0.001. NS=not significant (p>0.05). All comparisons are pre-operative vs. 2-year postoperative values using the paired sample t-test (normally distributed variables) or Wilcoxon signed-rank test (non-normally distributed variables). N/A: Not applicable
Spinopelvic parameters improved significantly following surgery [Table 2]. SS increased from a mean of 24.7 ± 2.2° preoperatively to 35.9 ± 3.5° at 2 years (mean change +11.2°, 95% CI: +10.6–+11.8; p < 0.001), reflecting restoration of lumbopelvic lordosis. PT decreased from 34.7 ± 3.2° to 22.8 ± 3.2° (mean change −11.9°, 95% CI: −12.5–−11.4; p < 0.001), indicating reduced pelvic retroversion and improved sagittal compensation. PI, as expected, remained unchanged (59.1 ± 3.8° at both time points; p = not significant [NS]), confirming the morphological constancy of this parameter. LL improved substantially from 37.7 ± 3.5° preoperatively to 54.2 ± 4.2° postoperatively (mean change +16.5°, 95% CI: +15.8–+17.2; p < 0.001). Most importantly, the PI–LL mismatch decreased from 21.1 ± 5.3° preoperatively to 4.8 ± 2.6° at 2 years (mean change −16.3°, 95% CI: −17.1–−15.5; p < 0.001), with the majority of patients achieving a PI–LL mismatch within the accepted threshold of ±9° at final follow-up.
Fusion status was assessed radiographically at 2 years using the Bridwell grading system by two independent radiologists [Table 3]. Grade I fusion (remodeled graft with visible trabeculae) was achieved in 62 patients (51.7%) and grade II fusion (graft present but not fully remodeled, no lucent lines) in 42 patients (35.0%), yielding a satisfactory fusion rate (grades I and II combined) of 86.7% (104/120). Grade III fusion (lucent lines at the graft interface) was noted in 12 patients (10.0%) and grade IV (absent fusion with graft collapse or resorption) in 4 patients (3.3%). Inter-observer reliability was excellent (intraclass correlation coefficient [ICC] 0.89, 95% CI: 0.84–0.94) and intra-observer reliability was similarly high (ICC 0.91, 95% CI: 0.87–0.95), confirming the consistency of radiographic assessment.
| Grade | Description | n (%) | Inter-observer ICC (95% CI) | Intra-observer ICC (95% CI) |
|---|---|---|---|---|
| I | Remodelled graft with trabeculae present | 62 (51.7) | 0.89 (0.84–0.94) | 0.91 (0.87–0.95) |
| II | Graft present, not fully remodelled, no lucent lines | 42 (35.0) | ||
| III | Graft present with lucent lines at top and/or bottom | 12 (10.0) | ||
| IV | Fusion absent, graft collapse or resorption | 4 (3.3) | ||
| Satisfactory fusion (Grades I+II) | 104 (86.7) | |||
ICC: Intraclass correlation coefficient, CI: Confidence interval
The overall complication rate was 6.7% (8/120 patients), with a reoperation rate of 1.7% (2/120), as detailed in Table 4. Dural tear occurred in 2 patients (1.7%) and was managed with primary intraoperative repair and 24-h bedrest (Clavien–Dindo grade IIIa). Surgical site infection was recorded in 2 patients (1.7%), requiring wound debridement and intravenous antibiotics (grade IIIb). Radiographic cage subsidence was observed in 3 patients (2.5%) and was managed conservatively without reoperation (grade I). Pedicle screw loosening occurred in 1 patient (0.8%) and necessitated one revision procedure (grade IIIb). Adjacent segment disease developed in 1 patient (0.8%) beyond 1 year postoperatively and required reoperation (grade IIIb). One patient (0.8%) developed a post-operative hematoma requiring surgical evacuation (grade IIIa). No permanent neurological deficits were recorded in any patient during the follow-up period.
| Sr. No. | Complication | n (%) | Management | Timing | Clavien–Dindo |
|---|---|---|---|---|---|
| 1 | Dural tear | 2 (1.7) | Primary intraoperative repair; 24-h bedrest | Intraoperative | Grade IIIa |
| 2 | Surgical site infection | 2 (1.7) | Wound debridement; intravenous antibiotics | Early postoperative | Grade IIIb |
| 3 | Radiographic cage subsidence | 3 (2.5) | Conservative observation; no reoperation | Late (> 3 months) | Grade I |
| 4 | Pedicle screw loosening | 1 (0.8) | Observation; one revision surgery | Late | Grade IIIb |
| 5 | Adjacent segment disease | 1 (0.8) | Conservative; one reoperation required | Late (> 1 year) | Grade IIIb |
| 6 | Postoperative haematoma | 1 (0.8) | Surgical evacuation | Early postoperative | Grade IIIa |
| Total patients with ≥ 1 complication | 8 (6.7) | Reoperation rate: 1.7% (2/120) | |||
| Total patients without any complication | 112 (93.3) | ||||
DISCUSSION
In this study of 120 adults undergoing single-level open PLIF with a PEEK cage for LS (63.3% degenerative, 36.7% isthmic; Meyerding grades I–III), we found that interbody cage implantation led to significantly better overall outcomes in sagittal alignment, with marked improvements in functional scores (ODI and VAS), a satisfactory Bridwell fusion rate of 86.7%, restoration of disc height and segmental lordosis, reduction in PI–LL mismatch, and improvement in all spinopelvic parameters (PT, SS, LL). The most common surgical levels were L4–L5 (45.8%) and L3–L4 (27.5%).
Our study’s results were in line with those of other research, including Chehrassan et al., Deng et al., and Diebo et al., demonstrating the reproducibility and dependability of these findings.[7-9]
Our results, in terms of restoration of Segmental Lordosis and greatly reducing PI-LL mismatch to within normal levels (ideally, LL should match PI within ±9° for sagittal balance), are similar to those of Deng et al. and Schwab et al.[8,10]
Furthermore, according to Park et al.,[11] SS, PT, LL, and sagittal balance all improved following surgical treatment of adult spondylolisthesis with PLIF and posterior instrumentation. Sagittal balance and pelvic characteristics changed as a result. There was a 4.4° rise in SS, a 4.4° decrease in PT, and a 5.6 mm posterior shift in sagittal balance.
The current study’s findings align with those of Kang et al., who showed that intervertebral cages in PLIF maintain intervertebral disc height better than autologous iliac bone dowels.[12]
The current study showed a clear and statistically significant improvement in all sagittal alignment parameters as well as functional scores (p < 0.001) following PLIF with cage use, in contrast to the results of a multicenter study, which reported no significant difference in radiological or clinical outcomes between PLIF performed with a cage and PLIF performed with local bone graft alone.[13]
The current study’s findings differ from those reported by Abdelbary and Arnaout who found no statistically significant difference between the groups and that both PLIF with bone graft alone and PLIF with cage plus graft produced similar clinical and radiological outcomes. On the other hand, after PLIF with cage insertion, our study showed a distinct and statistically significant improvement in all assessed sagittal parameters and functional outcomes (p < 0.001).[14]
LL restoration is essential for lumbar fusion because it improves long-term functional outcomes, restores sagittal balance, and lessens shear stress on adjacent segments.[15,16]
Li et al.’s study has shown that cage position, angle, size, material, and especially how far forward the cage sits in the disc space all affect the lordosis achieved and the risk of subsidence. While high-angle cages can correct alignment more powerfully, they also carry a higher chance of endplate violation if not used carefully.[17]
As sagittal balance has become the backbone of modern spine surgery, cages that help restore lordosis have become significant, and our study supports their role in improving not just alignment but actual patient-reported outcomes.[18]
In our study, pre-operative ODI ranged from 55 to 80% with a mean 69.93%. It significantly decreased postoperatively to a range from 15 to 35% and mean 22.67%, and pre-operative VAS ranged from 7 to 9, with a mean of 7.93. It significantly decreased postoperatively to a range from 3 to 5, with a mean of 3.9 (p < 0.001), and so our findings are consistent with those of Cheng et al.[19]
In the current study, the overall complication rate was 6.7% (8/120 patients), with a reoperation rate of 1.7% (2/120). Complications included dural tear in 2 patients (1.7%), managed with primary intraoperative repair and 24-h bedrest (Clavien–Dindo grade IIIa); surgical site infection in 2 patients (1.7%), managed with wound debridement and intravenous antibiotics (grade IIIb); radiographic cage subsidence in 3 patients (2.5%), managed conservatively without reoperation (grade I); pedicle screw loosening in 1 patient (0.8%), requiring one revision procedure (grade IIIb); adjacent segment disease in 1 patient (0.8%), requiring one reoperation (grade IIIb); and post-operative hematoma in 1 patient (0.8%), managed with surgical evacuation (grade IIIa). No neurological deficits were recorded in the post-operative period. All 120 patients completed the 2-year follow-up; no cases were lost to follow-up. These findings suggest that the complication profile of open PLIF with a PEEK cage is acceptable, particularly when strict patient selection criteria, meticulous surgical technique, and consistent perioperative management are applied; however, this should be interpreted with caution, given the sample size and study design. Complications still exist, such as subsidence, cage migration, and approach-specific risks, but many of these can be mitigated through careful endplate preparation, cage sizing, appropriate choice of approach, and use of minimally invasive surgery or navigated techniques, which, in many reports, reduce blood loss and shorten recovery.[20]
Cages tend to offer the greatest benefit in patients with low- to mid-grade slips, disc height loss, foraminal stenosis, or a PI– LL mismatch where restoring segmental lordosis directly influences symptoms and long-term mechanical balance.[21] There are limitations to our study: A small sample size, the absence of a control group, and the analysis performed at a single center. In addition, the retrospective design introduces inherent selection bias, and the absence of long-term follow-up beyond 2 years limits conclusions regarding implant longevity and adjacent segment degeneration. The lack of intraoperative navigation or post-operative CT-based cage position assessment is an acknowledged methodological constraint. Future prospective, multi-center, randomized controlled studies with longer follow-up periods are warranted to validate these findings further.
CONCLUSION
Cage use in PLIF resulted in statistically and clinically significant improvements in mechanical stability, fusion success, functional recovery, and spinopelvic sagittal alignment in LS. Our findings support the routine implantation of cages in surgical planning. Cages are a potent biomechanical tool and should be considered standard in contemporary spinal fusion operations since alignment correction is the primary objective in LS.
Authors’ contributions:
MAH: Conceived and designed the study, participated in data collection, performed the data analysis and interpretation, and wrote the original draft of the manuscript; MOR: Contributed to data collection, assisted in data analysis, and participated in manuscript drafting; MB: Contributed to study supervision, methodology refinement, and critically revised the manuscript for important intellectual content; HH: Data analysis and participated in manuscript drafting; HE: Data collection, manuscript editing; HG: contributed to study supervision, validation of the results, and manuscript review and editing. All authors have critically reviewed and approved the final draft and are responsible for the manuscript’s content and similarity index.
Ethical approval:
The research/study approved by the Institutional Review Board at Kafrelsheikh University Hospitals, number KFSIRB200-394, dated September 30, 2024.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given consent for clinical information to be reported in the journal. The patient understands that the patient’s names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of AI-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Conflicts of interest:
There are no conflicting relationships or activities.
Financial support and sponsorship: This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors
References
- Effects of different pedicle screw insertion depths on sagittal balance of lumbar degenerative spondylolisthesis, a retrospective comparative study. BMC Musculoskelet Disord. 2021;22:850.
- [CrossRef] [PubMed] [Google Scholar]
- Comparison of posterior and transforaminal approaches to lumbar interbody fusion. Spine (Phila Pa 1976). 2001;26:567-71.
- [CrossRef] [PubMed] [Google Scholar]
- Evidence showing the relationship between sagittal balance and clinical outcomes in surgical treatment of degenerative spinal diseases: A literature review. Int Orthop. 2015;39:87-95.
- [CrossRef] [PubMed] [Google Scholar]
- The effect of sagittal alignment, coronal balance, and segmental stability on preoperative patient-reported outcomes in patients with degenerative lumbar spondylolisthesis. BMC Surg. 2023;23:48.
- [CrossRef] [PubMed] [Google Scholar]
- Evaluation of spino-pelvic parameters according to intraoperative position in lumbosacral spine arthrodesis. Coluna/Columna. 2013;12:228-31.
- [CrossRef] [Google Scholar]
- Effects of different orientations of cage implantation on lumbar interbody fusion. World Neurosurg. 2020;140:e97-104.
- [CrossRef] [PubMed] [Google Scholar]
- Comparative outcomes of polyetheretherketone cage versus autograft harvested from en bloc laminectomy in posterior lumbar interbody fusion for low-grade spondylolisthesis. J Craniovertebr Junction Spine. 2025;16:266-70.
- [CrossRef] [PubMed] [Google Scholar]
- Effects of cage implantation depth on sagittal parameters and functional outcomes in posterior lumbar interbody fusion for the treatment of L4-L5 lumbar degenerative spondylolisthesis. Orthop Surg. 2024;16:1327-35.
- [CrossRef] [PubMed] [Google Scholar]
- Sagittal alignment in the degenerative lumbar spine: Surgical planning. J Bone Joint Surg Am. 2024;106:445-57.
- [CrossRef] [PubMed] [Google Scholar]
- Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: A prospective multicenter analysis. Spine (Phila Pa 1976). 2013;38:E803-12.
- [CrossRef] [PubMed] [Google Scholar]
- Postoperative changes in pelvic parameters and sagittal balance in adult isthmic spondylolisthesis. Oper Neurosurg. 2011;68:355-63.
- [CrossRef] [PubMed] [Google Scholar]
- What are the differences in outcome among various fusion methods of the lumbar spine? J Korean Neurosurg Soc. 2005;37:39-43.
- [Google Scholar]
- A comparative study between local bone graft with a cage and with no cage in single posterior lumbar interbody fusion (PLIF): A multicenter study. Arch Orthop Trauma Surg. 2014;134:1051-7.
- [CrossRef] [PubMed] [Google Scholar]
- Bone graft alone versus cage with bone graft in lumbar spine interbody fusion. Zagazig Univ Med J. 2021;27:1494-502.
- [Google Scholar]
- Segmental lordosis restoration during lumbar degenerative spinal fusion: Surgical techniques and outcomes. JAAOS J Am Acad Orthop Surg. 2025;33:e1051-9.
- [CrossRef] [PubMed] [Google Scholar]
- Clinical significance of lordosis orientation on proximal junctional kyphosis development in long-segment fusion surgery for adult spinal deformity. World Neurosurg. 2024;183:e282-92.
- [CrossRef] [PubMed] [Google Scholar]
- An update of interbody cages for spine fusion surgeries: From shape design to materials. Expert Rev Med Devices. 2022;19:977-89.
- [CrossRef] [PubMed] [Google Scholar]
- Lumbar spine research society 17th annual scientific meeting. J Neurosurg Spine. 2024;40:1-112.
- [CrossRef] [PubMed] [Google Scholar]
- Posterior lumbar interbody fusion versus posterolateral fusion in spondylolisthesis: A prospective controlled study in the Han nationality. Int Orthop. 2009;33:1043-7.
- [CrossRef] [PubMed] [Google Scholar]
- 3D-printed titanium cages for anterior and lateral lumbar interbody fusion result in excellent fusion rates one year after surgery. Glob Spine J. 2026;16:341-8.
- [CrossRef] [PubMed] [Google Scholar]
- Functional outcome of surgical management of low mid-grade lumbar spondylolisthesis when considering the sagittal balance parameters preoperatively: A prospective study. Chinese Neurosurg J. 2022;8:35.
- [CrossRef] [PubMed] [Google Scholar]