Comparison of cage with plate versus tricortical iliac crest graft with plate fixation in anterior cervical discectomy and fusion: A retrospective study

INTRODUCTION

Cervical myelopathy is a disabling condition that commonly arises as a consequence of cervical spondylosis affecting vertebral structures. When cervical myelopathy develops secondary to degenerative spondylosis, it is known as cervical spondylotic myelopathy (CSM). Patients may present with impaired coordination, reduced manual dexterity, gait disturbance, urinary dysfunction, muscle weakness, sensory changes, and abnormal reflexes.^[1]

The pathophysiology of CSM involves both static and dynamic spinal cord compression. Static compression results from osteophyte formation, disc degeneration, and ligamentum flavum hypertrophy. Dynamic compression arises from cervical motion – flexion increases disc bulging, and extension causes ligamentum thickening – leading to a fluctuant narrowing of the spinal canal. Cadaveric studies confirm that canal dimensions vary with motion, with flexion expanding the space compared to extension.^[2,3] This cyclical compression contributes to ischemia and neuronal injury over time.

Age-related degeneration amplifies CSM pathogenesis; intervertebral disc dehydration, loss of height, and segmental instability diminish spinal canal capacity and impair cord perfusion.^[4,5] If unaddressed, these changes lead to progressive neurological deterioration.

Anterior cervical discectomy and fusion (ACDF) is a standard surgical intervention for degenerative cervical disc disease and CSM. Initially described by Robinson and Smith, ACDF achieves decompression, restores disc height, and maintains spinal alignment while promoting stabilization and fusion.^[6-9]

Fusion options after discectomy include tricortical iliac crest autografts, allografts, synthetic substitutes, and interbody cages, often supported with anterior plating.^[10-12] Each method presents advantages and pitfalls: autografts have osteogenic properties but donor-site morbidity; standalone grafts risk subsidence and non-union; plating improves stability but can cause hardware-related complications such as plate loosening, screw failure, longer operative time, and soft tissue irritation.^[10,11]

In this study, we evaluated two commonly employed strategies for ACDF:

1. Use of an autologous tricortical iliac crest bone graft combined with a locked anterior cervical plate, and

2. Use of a titanium interbody cage filled with cancellous bone cylinders obtained using a minimally invasive technique, also stabilized with a locked anterior cervical plate.^[12]

Over the past two decades, comparative studies have shown equivalent fusion rates and outcomes between cages and autografts, with cages offering reduced operative time and donor-site pain.^[13-17] Others support superior long-term biological integration using autografts, especially in multilevel fusions.^[18-21] A systematic review by Verhagen et al. highlights variable outcomes across studies.^[16]

Recent meta-analyses and systematic reviews maintain the controversy: while cages reduce donor-site morbidity, autografts still demonstrate strong fusion, particularly at longer follow-up.^[17,21] Multicenter data suggest that the choice of technique may largely depend on surgeon preference, patient anatomy, and comorbidities, with both approaches achieving acceptable outcomes in properly selected cases.^[22-26]

Technological advances have also introduced new implant designs. Stand-alone self-locking cages have demonstrated reductions in operative time, blood loss, dysphagia, and adjacent segment degeneration compared to cage-plus-plate constructs in single-level ACDF, while maintaining comparable fusion and subsidence rates.^[10,11] Similarly, recent innovations such as bioactive glass-ceramic cages and 3D-printed porous titanium cages have shown promising fusion rates and biocompatibility when compared with conventional polyetheretherketone (PEEK) constructs.^[18] These developments highlight an ongoing evolution in fusion technology, with efforts directed at improving implant integration and reducing morbidity.

Given this backdrop and persistent controversy, the present study was undertaken to compare two widely used ACDF techniques – cage with plate fixation versus tricortical iliac crest graft (ICG) with plate fixation – with respect to fusion success, functional outcomes, and post-operative complications, using long-term data from a single-center cohort.

MATERIAL AND METHODS

RESULTS

A total of 194 patients were included in the study: 100 underwent ACDF with cage and plate fixation, and 94 underwent ACDF with tricortical ICG and plate fixation.

Demographics

The mean age was 50.2 ± 10.1 years in the cage group and 53.4 ± 6.5 years in the graft group. In both groups, males were more common than females (65 vs. 35 in the cage; 64 vs. 30 in the graft). The mean follow-up duration was 16.4 ± 2.1 months in the cage group and 17.8 ± 1.5 months in the graft group. The most commonly involved level in both groups was C5–C6 (54 cases in cage, 50 in graft), followed by C6–C7. Complete demographic details are shown in [Table 1, Figures 1 and 2].

Table 1: Demographic data of patients.

Variable	Cage group	Tricortical graft with plate group
Number of patients	100	94
Mean age, (mean±SD)	50.2±10.1	53.4±6.5
Male	65	64
Female	35	30
Follow-up period (months), (mean±SD)	16.4±2.1	17.8±1.5
Involved level - C3-C4	5	8
C4-C5	11	10
C5-C6	54	50
C6-C7	30	26

SD: Standard deviation

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Figure 1: (a and b) Preoperative saggital T2-weghted magnetic resonance imaging of the cervical spine showing significant cord compression and hyperintense signal changes suggestive of myelopathy and a large C5-C6 disc prolapse with partial collapse of the C5 vertebral body, (a) red arrow, (b) green arrow.

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Figure 2: (a and b) Preoperative axial T2-weighted magnetic resonance imaging at the C5–C6 level (red and green arrow) showing a large central and paracentral disc prolapse with severe cord compression and surrounding hyperintense signal suggestive of myelopathy.

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Fusion and functional outcomes

Solid radiological fusion was achieved in 100% of patients in both groups at final follow-up. According to Odom’s criteria, excellent-to-good outcomes were seen in 83 patients (83%) in the cage group and 82 patients (87%) in the graft group, while fair or poor results were observed in 7 and 12 patients, respectively (p = 0.001). Pain outcomes improved in both groups: mean post-operative VAS was 45.32 ± 10.2 in the cage group and 41.5 ± 11.1 in the graft group (p = 0.034). These findings are summarized in Table 2.

Table 2: Functional outcome in both groups.

Variable	Cage group (n=100)	Graft with plate (n=94)	p-value
Radiological fusion
Complete union	100	94
Non-union	-	-
Odom rating
Excellent	45	42	0.001*
Good	38	40
Fair	5	10
Poor	2	2
VAS (mean±SD)	45.32±10.2	41.5±11.1	0.034

Values are mean±SD or n (%). VAS: Visual analog scale (0=No pain, 100=Worst pain). p value <0.05 = Significant. *highly significant

Radiological fusion is defined as bridging trabeculae and ≤2 mm interspinous motion. Between-group comparisons used an independent samples t-test for VAS and Chi-square test for categorical variables [Figures 3 and 4].

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Figure 4: Postoperative cervical radiographs (a) anteroposterior view and (b) lateral view at six months following C5 corpectomy with bone grafting demonstrating stable instrumentation and complete fusion at the operative level, (a) red arrow, (b) green arrow.

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Figure 3: Postoperative radiographs of the cervical spine (a) anteroposterior view and (b) lateral view three months following C5 corpectomy with bone grafting showing anterior cervical plate fixation and evidence of progressing fusion (red arrows).

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DISCUSSION

ACDF is a well-established technique for the management of degenerative cervical spine disease associated with radiculopathy and myelopathy.^[11] Over the years, multiple modifications of this procedure have been introduced, including the use of different graft materials and fixation devices. Despite extensive clinical use, no universal consensus has been reached regarding the superiority of any single technique.^[15]

The fundamental objective of ACDF is to decompress the neural elements and achieve a stable fusion that maintains cervical alignment. Both tricortical ICGs with plate fixation and biomechanical interbody spacers, such as cages, effectively restore disc height, relieve compression, and increase foraminal dimensions through ligamentotaxis.^[16] By restricting abnormal motion, fusion reduces radicular pain and may contribute to partial resorption of osteophytes.

In our study, most patients were in the 50–60-year age group, with a male predominance in both treatment groups. These demographic findings are consistent with prior literature. Spallone and Marchione reported a mean age of 49.1 ± 12.1 years in their cohort.^[18] Sharma and Kishore, found a mean age of 51.07 ± 9.39 years in the autograft group and 47.3 ± 9.3 years in the PEEK cage group.^[19] Similarly, studies by Sharma and Kishore, Siddiqui and Jackowski, Lee and Jang, Adam et al.^{[19,20,22,23]} also reported a predominance of male patients.

In terms of functional outcome, excellent-to-good recovery was achieved in 83% of the cage group and 87% of the graft group (p = 0.001). These findings parallel those of Ayman and Galhom who reported 90% excellent-to-good outcomes in the cage group and 85% in the bone graft group.^[24] Islam et al. also observed comparable functional improvement, with 93.3% of cage patients and 86.6% of autograft patients achieving excellent or good outcomes.^[25] Pain relief was also significant in our series, with mean post-operative VAS scores of 45.32 ± 10.2 in the cage group and 41.5 ± 11.1 in the graft group (p = 0.034), consistent with Spallone and Marchione, who reported substantial improvement in both neck and arm pain after ACDF.^[18]

Complication rates in our study were low and comparable between groups. Dysphagia was transient and observed in 6 patients in the cage group and 5 in the graft group, resolving spontaneously within weeks, similar to the findings of Ayman and Galhom^[24] and Islam et al.^[25] Cage subsidence was seen only in 2 cage patients, while donor-site morbidity, including persistent iliac crest pain, was unique to the autograft group, affecting 20 patients, with 4 requiring additional analgesic therapy. These findings reaffirm the trade-off between the biological fusion advantages of autografts and donor-site morbidity risks.

Recent literature continues to highlight this controversy. Alhashash et al. reported comparable clinical outcomes and fusion rates between cage constructs and grafts at 5-year follow-up, but noted less donor-site morbidity with cages.^[27] Yang et al., in a meta-analysis, concluded that cage constructs significantly reduce perioperative complications, though long-term outcomes were similar to autografts.^[17] Xu et al. observed that tricortical autografts may still provide superior biological fusion in multilevel cases, whereas cages offer predictable results in single-level procedures.^[21] Contemporary reviews emphasize individualized decision-making, balancing the advantages of each technique against patient-specific factors.^[26,28]

Our study adds to this evidence by demonstrating equivalent fusion and functional outcomes between cage and autograft with plate fixation, while highlighting the donor-site morbidity uniquely associated with iliac crest harvest.

CONCLUSION

The ACDF procedure is considered an optimal approach for the treatment of degenerative cervical disc disease, as it consistently yields favorable functional results and successful fusion. This can be achieved using either a cage with plate fixation or a tricortical ICG with plate fixation.

In our study, there was no notable difference in post-operative monitoring, fusion rates, or clinical and functional outcomes between the cage and tricortical ICG groups. The use of a tricortical ICG combined with a plate remains a highly effective treatment, providing strong fusion and sufficient stability with the addition of anterior plating. Conversely, the use of a cage serves as an equally efficient alternative, offering reduced surgical duration, reliable fusion outcomes, and fewer donor-site complications.

Further prospective multicenter studies with longer follow-up are warranted to validate these findings, assess cost-effectiveness, and evaluate newer cage designs and biomaterials that may further improve fusion rates and reduce complication profiles.