Is anterior cervical discectomy and fusion sufficient for single-level cervical myelopathy: surgical considerations for combined anterior and posterior cervical cord compression—experience from a case series

Introduction

The surgical strategy for cervical myelopathy depends on multiple factors, including whether the compression is multilevel, the sagittal alignment, and flexibility of cervical segmental motion. One useful concept is the K-line, defined as a line connecting the midpoints of the spinal canal at C2 and C7 on a lateral radiograph. When the compressive lesion lies entirely anterior to this line, the case is considered K-line positive; if the lesion crosses the line, it is K-line negative (1). Considering these factors, surgeons generally choose an appropriate surgical approach; however, some degree of variation in decision-making inevitably exists among individual surgeons (2).

For single-disc-level cervical myelopathy, anterior cervical discectomy and fusion (ACDF) is the standard surgical treatment option in most cases (3). Nevertheless, single-level myelopathy does not represent a homogeneous entity (4,5). In addition to anterior disc herniation or ossification of posterior longitudinal ligament (OPLL), patients may involve combined posterior cord compression from ligamentum flavum (LF) hypertrophy, or may be at risk of postoperative LF buckling following segmental lordosis correction after ACDF. These situations may lead to insufficient decompression or, in some cases, the iatrogenic neurological deficits (6,7).

Posterior approaches, such as laminoplasty or laminectomy, are generally indicated in multilevel compression or K-line negative patients (8-10). In selected single-level cases with significant posterior pathology, these posterior approaches may also be required. However, in single-level myelopathy, posterior surgery usually involves a wider surgical exposure than necessary, and therefore it is generally not preferred by most surgeons.

The purpose of this case series is to present patients with single-level cervical myelopathy involving both anterior and posterior cord compression and to discuss surgical considerations and technical options that may optimize outcomes in these challenging scenarios. We present this article in accordance with the AME Case Series reporting checklist (available at https://jss.amegroups.com/article/view/10.21037/jss-25-181/rc).

Case presentation

All procedures performed in this study were in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Institutional Review Board of Kangwon National University Hospital (No. 2023-12-009). Written informed consent for publication of this case series and accompanying images was not obtained from the patients or the relatives after all possible attempts were made.

Study design

This study was conducted to evaluate the surgical outcomes of ACDF using a modified plate fixation technique for various types of single-level cervical myelopathy. Between August 2023 and January 2024, four consecutive patients underwent surgery at our institution, and all procedures were performed by a single surgeon (C.G.H.).

Case 1

A 68-year-old man presented with a 3–4-month history of progressive fine motor dysfunction and hand clumsiness. He reported difficulty grasping and lifting objects with his left hand, frequently dropping items, and subjective weakness in the left upper extremity. Neurological examination confirmed motor weakness in the left upper limb.

Plain radiographs revealed disc space narrowing and spondylotic changes at the C3/4 level, with associated shortening of the interspinous distance at the same segment (Figure 1). Magnetic resonance imaging (MRI) demonstrated C3/4 disc herniation accompanied by hypertrophy of the LF, resulting in combined anterior and posterior spinal cord compression. Signal changes within the spinal cord at the involved level were also noted (Figure 1). Given the coexistence of radicular symptoms and weakness in the left upper extremity, the patient was diagnosed with cervical myeloradiculopathy.

Figure 1 Pre- and postoperative imaging of Case 1. (A) Preoperative lateral radiograph demonstrating spondylosis with disc space narrowing at C3/4. (B,C) Preoperative sagittal MRI showing disc herniation and ligamentum flavum thickening at C3/4, resulting in combined anterior and posterior cord compression with intramedullary signal change. (D) Postoperative lateral radiograph confirming anterior cervical discectomy and fusion with fixation using a short plate and high-angle screws. MRI, magnetic resonance imaging.

Although ACDF was considered the standard approach for decompression of the spinal cord and left neural foramen, the presence of significant posterior cord compression due to LF hypertrophy raised concern that ACDF alone might not provide sufficient decompression. To address this, the “Indirect Posterior Decompression via ACDF” technique was planned (10). This strategy relies on anterior compression during plating to induce posterior LF stretching, thereby achieving both anterior and posterior decompression without an additional posterior surgery.

At the 6-month postoperative follow-up, the patient’s Japanese Orthopaedic Association (JOA) score improved from 14 to 17. Left upper extremity motor weakness and fine motor dysfunction demonstrated marked clinical improvement.

Surgical techniques

The procedure was performed using a standard anterior cervical approach (Figure 2A). After adequate discectomy and foraminotomy were carried out at the C3/4 level, a laminar spreader was inserted to gently widen the disc space and confirm segmental mobility. However, if the disc space cannot be sufficiently widened, it could lead to insufficient indirect decompression for posterior cord compression. A cage was then placed into the intervertebral space, which restored segmental lordosis. However, such lordotic correction typically reduces the posterior interspinous distance, potentially increasing the risk of LF buckling (Figure 2B).

Figure 2 Intraoperative fluoroscopy demonstrating indirect posterior decompression technique. (A) Level confirmation with guide pin at C3/4 disc space. (B) Following discectomy and cage insertion, segmental lordosis restoration decreased interspinous distance from 9.6 to 7.4 mm, indicating ligamentum flavum buckling risk. (C) Short anterior plate with high-angle screw fixation achieved anterior compression with posterior distraction, increasing interspinous distance from 7.4 to 11.3 mm and demonstrating effective indirect ligamentum flavum relaxation.

To prevent this, a short anterior cervical plate with high angle screw was selected. Screws were inserted at a relatively high angle near the endplates, initially left loosely fixed to allow adjustment. Once the appropriate plate and screws position was confirmed, the plate was manually pressed downward while the screws were tightened. This maneuver created a “lag screw effect”, compressing the anterior cage while inducing relaxation posterior structures (Figure 2C). As a result, the posterior LF was stretched, achieving indirect decompression of the dorsal cord without the need for posterior surgery. This effect cannot be reliably obtained when a long plate is used or when screws are placed in a parallel orientation.

Case 2

An 80-year-old female presented with progressive gait difficulty over the past 6 months. She also reported bilateral hand numbness that had persisted for several years. On neurological examination, knee jerk hyperreflexia was noted, and tandem gait was positive. Plain radiographs revealed retrolisthesis at C3/4 (Figure 3). MRI demonstrated disc herniation and LF thickening at the C3/4 level, resulting in combined anterior and posterior cord compression with intramedullary signal change.

Figure 3 Case 2: an 80-year-old female with cervical myelopathy at C3/4. (A) Preoperative lateral radiograph demonstrates C3/4 disc space narrowing with retrolisthesis. (B) Preoperative sagittal T2-weighted MRI shows anterior and posterior cord compression at C3/4 with intramedullary T2 hyperintensity, consistent with cervical myelopathy. (C) Postoperative lateral radiograph following ACDF with short plate and high-angle screw fixation demonstrates restored disc height and appropriate interspinous distance widening. (D) Postoperative sagittal T2-weighted MRI confirms adequate cord decompression at C3/4 with resolution of compression. ACDF, anterior cervical discectomy and fusion; MRI, magnetic resonance imaging.

The patient was diagnosed with cervical myelopathy at C3/4 and underwent ACDF. Postoperatively, the numbness in both hands resolved, and her gait improved significantly. At 6-month follow-up, her JOA score improved from 12 to 17. Postoperative MRI confirmed that adequate decompression of the spinal cord was achieved from both anterior and posterior aspects.

Case 3

A 58-year-old female presented with progressive axial neck pain and hand clumsiness of 1-year duration. She reported impaired fine motor function including difficulty with chopsticks use and writing. While maintaining normal baseline gait, she experienced intermittent unsteadiness during rapid ambulation. Plain radiographs and CT demonstrated mixed-type OPLL extending from C2–C6. MRI revealed focal cord compression with intramedullary signal changes at C3/4, consistent with cervical myelopathy at this level (Figure 4).

Figure 4 Case 3: a 58-year-old female with cervical myelopathy secondary to mixed-type OPLL. (A) Preoperative lateral radiograph and (B) sagittal CT demonstrate mixed-type OPLL extending from C2–C6. (C) Preoperative sagittal T2-weighted MRI shows focal cord compression with intramedullary T2 hyperintensity at C3/4. (D,E) Axial CT and T2-weighted MRI at C3/4 level reveal spinal canal stenosis from OPLL. (F) Postoperative lateral radiograph following ACDF with standard anterior plate and low-angle screw fixation. (G) Postoperative sagittal T2-weighted MRI demonstrates ligamentum flavum buckling secondary to segmental lordosis restoration, causing mild residual posterior cord compression. ACDF, anterior cervical discectomy and fusion; CT, computed tomography; MRI, magnetic resonance imaging; OPLL, ossification of the posterior longitudinal ligament.

Given the absence of significant posterior cord compression, ACDF at C3/4 was performed using a standard anterior plate with low-angle screw fixation. At 2 weeks postoperatively, the patient demonstrated improvement in hand clumsiness. However, postoperative MRI revealed LF buckling secondary to surgical lordosis restoration, resulting in mild residual posterior cord compression. Despite this finding, satisfactory neurological improvement was achieved (JOA score: 14→16), prompting conservative management with serial clinical and radiographic monitoring rather than additional posterior decompression.

Case 4

A 77-year-old male presented with 1-month progressive gait impairment and lower extremity weakness. Additional symptoms included fine motor dysfunction and neurogenic bowel/bladder disturbance. Neurological examination revealed grade 3 motor strength in bilateral lower extremities with positive Hoffman reflex and abnormal tandem gait. The patient reported subjective worsening of ambulatory function. Plain radiographs demonstrated severe cervical spondylosis with rigid kyphotic deformity (Figure 5). MRI revealed cord compression at C5/6 secondary to disc herniation and LF hypertrophy, consistent with cervical myelopathy. ACDF at C5/6 was planned to achieve combined anterior and posterior decompression. Intraoperatively, following discectomy and lamina spreader application, locked facet joints prevented adequate disc space distraction, precluding effective indirect posterior decompression. A cage was inserted with short-plate fixation using high-angle screws. However, intraoperative fluoroscopy demonstrated insufficient interspinous distance widening. Postoperative MRI confirmed adequate anterior decompression but revealed persistent posterior compression by hypertrophied LF. Consequently, second-stage posterior laminectomy with flavectomy at C5 was performed. At 3-month follow-up, neurological improvement was demonstrated with JOA score increase from 12 to 15, and the patient continued structured gait rehabilitation.

Figure 5 Case 4: a 77-year-old male with cervical myelopathy and rigid kyphotic deformity. (A) Preoperative AP radiograph demonstrates diffuse cervical spondylosis with facet joint hypertrophy and osteophytic spurring. (B) Lateral radiograph shows spontaneous C4/5 fusion with rigid cervical kyphosis. (C,D) Preoperative sagittal T2-weighted MRI reveals cord compression with intramedullary T2 hyperintensity at C5/6. (E-G) Intraoperative fluoroscopy images: (E) operative level confirmation showing severe disc space narrowing, (F) following discectomy and cage insertion, and (G) after anterior plate fixation demonstrating persistent interspinous distance narrowing. (H) Postoperative lateral radiograph following ACDF. (I,J) Postoperative sagittal T2-weighted MRI shows persistent posterior cord compression at C5/6. (K) Lateral radiograph after staged C5 laminectomy (* indicates resected C5 lamina). ACDF, anterior cervical discectomy and fusion; AP, anteroposterior; MRI, magnetic resonance imaging.

Discussion

Surgical method of cervical myelopathy is selected by compression location (anterior and/or posterior), number of affected levels, sagittal alignment, and segmental mobility. While ACDF remains the gold standard for disc-level pathology with established efficacy in neurological recovery and fusion rates, its limitations become apparent in cases with concurrent posterior compression (3-5).

ACDF primarily addresses anterior pathology but may prove inadequate when significant posterior cord compression coexists, particularly from LF hypertrophy or buckling. Recent evidence demonstrates that higher-grade posterior LF compression correlates with suboptimal neurological outcomes following ACDF (7). Moreover, indirect posterior decompression through ACDF occurs unpredictably, with up to 40% of patients demonstrating persistent posterior compression (11-13).

Combined anterior-posterior approaches address this limitation but incur significant morbidity including increased operative duration, blood loss, and complication rates (8,14). To mitigate these risks, technical modifications to ACDF have emerged, specifically employing short anterior plates with high angle screw angulation to generate controlled anterior compression while inducing posterior distraction, theoretically stretching the LF and achieving indirect dorsal decompression (2,10,15). Radiological studies suggest disc height restoration influences LF morphology, though results remain inconsistent (9,12).

Our case series illustrates both the potential and limitations of this approach. Cases 1 and 2 demonstrated successful indirect posterior decompression with satisfactory clinical and radiological outcomes, obviating posterior surgery. Conversely, Case 3 revealed a potential complication: iatrogenic LF buckling following standard plating with lordotic correction, emphasizing the critical importance of implant selection and screw trajectory. Case 4 highlighted the inherent limitations in patients with rigid segmental motion and facet ankylosis, where indirect decompression proved insufficient, necessitating staged posterior intervention (6,7,10).

Short anterior plating with high-angle screw fixation may confer several biomechanical advantages: enhanced indirect posterior decompression through controlled segmental alignment, improved cage stability, reduced cage subsidence risk, and more physiological load distribution. However, success depends on meticulous patient selection, intraoperative mobility assessment, and precise technical execution (12,15,16).

Recent studies have shown that indirect posterior decompression after ACDF depends not only on the severity of LF compression but more importantly on the mobility of the involved segment. Our findings are consistent: indirect decompression succeeded only in segments with sufficient motion, whereas it failed in cases with facet locking or rigid deformity. Therefore, posterior compression should always be interpreted alongside segmental mobility, and rigid segments may require combined or staged posterior decompression (7,10).

Conclusions

ACDF remains highly effective for disc-level cervical myelopathy with predominant anterior compression. In carefully selected patients, technical modifications including short anterior plating with high-angle screw fixation may achieve adequate indirect posterior decompression while preventing LF buckling and avoiding staged posterior procedures. However, in patients with limited segmental mobility, surgeons should recognize the limitations of indirect decompression and consider primary combined anterior-posterior approaches to ensure adequate neural decompression (8,14).

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the AME Case Series reporting checklist. Available at https://jss.amegroups.com/article/view/10.21037/jss-25-181/rc

Peer Review File: Available at https://jss.amegroups.com/article/view/10.21037/jss-25-181/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-25-181/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Institutional Review Board of Kangwon National University Hospital (No. 2023-12-009). Written informed consent for publication of this case series and accompanying images was not obtained from the patients or the relatives after all possible attempts were made.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Ijima Y, Okada E, Matsumoto M, et al. K-line–related factors and surgical outcomes in cervical ossification of the posterior longitudinal ligament: a multicenter study. Spine (Phila Pa 1976) 2021;46:E525-33.
2. Taghvaei M, Meybodi KT, Zeinalizadeh M. Ligamentum Flavum Buckling Causing Immediate Post-Operative Neurological Deterioration After an Anterior Cervical Discectomy: Case Report. Turk Neurosurg 2018;28:678-81. [Crossref] [PubMed]
3. Lee DH, Lee SW, Kang SJ, et al. Surgical outcome of multilevel anterior cervical discectomy and fusion for degenerative cervical myelopathy. Sci Rep 2022;12:13025. [Crossref] [PubMed]
4. Bakr O, Salameh M, et al. Laminoplasty versus laminectomy with fusion for treating degenerative cervical myelopathy: a systematic review. Eur Spine J 2023;32:1492-503. [Crossref] [PubMed]
5. Zhao H, Wang C, Sun Y, et al. Comparison of laminoplasty versus laminectomy with fusion for cervical spondylotic myelopathy: a meta-analysis. World Neurosurg 2022;159:e471-82.
6. Taghvaei M, Meybodi KT, Zeinalizadeh M. Ligamentum Flavum Buckling Causing Immediate Post-Operative Neurological Deterioration After an Anterior Cervical Discectomy: Case Report. Turk Neurosurg 2018;28:678-81. [Crossref] [PubMed]
7. Park S, Lee DH, Lee CS, et al. Posterior cord compression from ligamentum flavum as a prognostic factor after ACDF. Spine (Phila Pa 1976) 2023;48:1526-34. [Crossref] [PubMed]
8. Fehlings MG, Tetreault LA, Riew KD, et al. A clinical practice guideline for the management of patients with degenerative cervical myelopathy. Global Spine J 2017;7:70S-83S. [Crossref] [PubMed]
9. Choi BW, Choi MS, Chang H. Radiological assessment of the effects of anterior cervical procedures on posterior ligamentum flavum geometry. Clin Orthop Surg 2021;13:499-506. [Crossref] [PubMed]
10. Lee GW, Seok SY, Yeom JS, et al. Indirect Posterior Decompression With a Plate Gliding Technique During an Anterior Cervical Discectomy and Fusion for Treatment of Cervical Myelopathy Accompanied by Ligamentum Flavum Pathologies: A Technical Note and Case Series. Clin Spine Surg 2025; Epub ahead of print. [Crossref]
11. Lee DH, Park S, Hwang CJ, et al. Could indirect decompression occur for cord compression by the ligamentum flavum with anterior cervical discectomy and fusion? J Neurosurg Spine 2024;42:100-109. [Crossref] [PubMed]
12. Choi BW, Choi MS, Chang H. Radiological Assessment of the Effects of Anterior Cervical Discectomy and Fusion on Distraction of the Posterior Ligamentum Flavum in Patients with Degenerative Cervical Spines. Clin Orthop Surg 2021;13:499-504. [Crossref] [PubMed]
13. Mazur-Hart DJ, Nguyen KT, Pettersson DR, et al. Early postoperative MRI findings following anterior cervical discectomy and fusion: What to expect when the unexpected happens. World Neurosurg X 2023;19:100188. [Crossref] [PubMed]
14. David Kaye I, Marascalchi BJ, Macagno AE, et al. Predictors of morbidity and mortality among patients with cervical spondylotic myelopathy treated surgically. Eur Spine J 2015;24:2910-7. [Crossref] [PubMed]
15. Huang W, Tian Y, Wang H, et al. Comparative analysis of the biomechanics of anterior cervical discectomy and fusion with multiple segmental plates fixation versus single multilevel plate fixation: a finite element study. BMC Musculoskelet Disord 2022;23:848. [Crossref] [PubMed]
16. Lee DH, Park S, Lee WS, et al. Vertebral Body Sliding Osteotomy for Cervical Myelopathy With Rigid Kyphosis. Neurospine 2020;17:640-7. [Crossref] [PubMed]