, Sung Tan Cho2
, Ayush Sharma3
, Watcharaporn Cholamjiak4
, Meng-Huang Wu5,6,7
, Lo Cho Yau8
, Hyun-Jin Park9
, Ho-Jin Lee10
1Department of Orthopaedics, School of Medicine, University of Phayao, Phayao, Thailand
2Department of Orthopedic Surgery, Seoul Seonam Hospital, Seoul, Korea
3Department of Orthopaedic, Dr B R Ambedkar Memorial Hospital, Mumbai, India
4Department of Mathematics, School of Science, University of Phayao, Phayao, Thailand
5Department of Orthopedics, Taipei Medical University Hospital, Taipei, Taiwan
6Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
7Prospective Innovation Center, Taipei Medical University Hospital, Taipei, Taiwan
8Department of Orthopaedics and Traumatology, North District Hospital, University of Hong Kong, Sheung Shui, Hong Kong
9Department of Orthopedic Surgery, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
10Department of Orthopaedic Surgery, Chungnam National University College of Medicine, Daejeon, Korea
Copyright © 2025 by the Korean Spinal Neurosurgery Society
This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Conflict of Interest
The authors have nothing to disclose.
Funding/Support
The Thailand Science Research and Innovation Fund (Fundamental Fund 2025, Grant No. 5025/2567) and School of Medicine, University of Phayao, Thailand.
Acknowledgments
All authors would like to thank the Thailand Science Research and Innovation Fund (Fundamental Fund 2025, Grant No. 5025/2567) and the School of Medicine, University of Phayao.
Author Contribution
Conceptualization: WL, STC, AS, WC, MHW, LCY, HJP, HJL; Data curation: WL, STC, AS, WC, MHW, LCY, HJP, HJL; Formal analysis: WL, WC; Methodology: WL, WC, MHW, LCY, HJP, HJL; Project administration: WL; Visualization: WL, STC, AS, WC, MHW, LCY, HJP, HJL; Writing – original draft: WL; Writing – review & editing: WL.
| No. | Study | Published year | Nationality | Type of study | Sample size (n) | Age (yr) | Female (%) | Male (%) | Symptom duration (wk) | Level of disc herniation | Previous conservative treatment (%) | Conservative treatment duration (wk) | Physical occupation (%) | Neurological deficits |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Ruetten et al. [5] | 2008 | Germany | Prospective, randomized, controlled | 175 | 27–62 (mean, 43) | 66 | 34 | 5 Days to 8 months (mean, 94 days) | C2–C3–C7–T1 | 85 | 10 | NM | Intolerable radicular pain or neurologic deficits |
| 2 | Kim et al. [6] | 2009 | South Korea | Prospective | 3 | 42, 46, 50 | 0 | 100 | 2 to 2 yr | C6–7 | NM | NM | 100 (all soldiers) | Triceps weakness, radicular pain, neck pain |
| 3 | Yang et al. [10] | 2014 | China | Retrospective comparative cohort | 84 | AFECD: 41.3 (28–57), PFECD: 40.5 (32–68) | AFECD: 38, PFECD: 33 | Not provided | AFECD: 6–46, PFECD: 2–48 | C3–4, C4–5, C5–6, C6–7 | Not explicitly mentioned | Minimum 4 | NM | Radiculopathy and/or myelopathy |
| 4 | Ye et al. [11] | 2017 | China | Clinical observation | 9 | 39–56 (mean, 46) | 33 | 66 | 2–26 (mean, 16) | C4–7 | 77 | 12 | NM | Intolerable radicular pain or neurologic deficits |
| 5 | Zheng et al. [12] | 2018 | China | Retrospective review of PECD cases | 252 | NM | 129/252 (51) | 120/252 (48) | NM | C3–4, C4–5, C5–6, C6–7 | 100 | 12 | NM | Radicular pain, single-level foraminal soft disc herniation or foraminal stenosis |
| 6 | Wan et al. [13] | 2018 | China | Prospective, clinical study | 25 | 27–57 (mean, 38) | 44 | 56 | 2 to 10 Mo (mean, 5.5) | C4–5, C5–6, C6–7, C7–T1 | NM | > 6 | NM | Arm/shoulder radicular pain, upper-extremity numbness, muscle weakness, weakened tendon reflex |
| 7 | Lee et al. [14] | 2018 | South Korea | Retrospective review | 106 | Mean: 49.2 (SD, 10.8) | 35.9 | 64.1 | Median: 2.3 mo | C5–6 | NM | NM | NM | Motor weakness in 72% of patients |
| 8 | Yu et al. [15] | 2019 | China | Retrospective observational study | 30 | 47.7 ± 12.5 (26–79) | 43.8 | 56.2 | Mean 19.5 mo | C3–4, C4–5, C5–6, C6–7 | NM | At least 4 | NM | Radiculopathy, myelopathy (Nurick grade ≤ 3) |
| 9 | Xiao et al. [16] | 2019 | China | Retrospective comparative study | 84 | 52.9 ± 14.3 (group A), 55.4 ± 12.3 (group B) | Group A (22) | Group A (18) | 11.2±5.6 mo (group A), 10.8 ± 5.8 mo (group B) | C4–5, C5–6, C6–7 | NM | NM | NM | Unilateral cervical radiculopathy with arm pain or loss of sensory/motor function |
| Group A: posterior percutaneous endoscopic cervical discectomy (P–PECD) | Group B (24) | Group B (20) | ||||||||||||
| Group B: P–PECD combined with partial pediculectomy | ||||||||||||||
| 10 | Shu et al. [17] | 2019 | China | Retrospective study | 32 | Mean: 63.0 ± 10.5 | 56.25 | 43.75 | At least 12 | C4–5, C5–6, C6–7 | All patients | Not specified | NM | Radicular pain with foraminal stenosis |
| 11 | Tong et al. [18] | 2020 | China | Retrospective cohort study | 46 | 54.22 ± 10.52 (VBD)/57.48 ± 7.80 (SDD) | 47.8 (VBD) | 52.2 (VBD) | 3 Mo (minimum) | C5–6, C6–7 | 100 (ineffective conservative treatment for 3 months) | NM | NM | Unilateral root symptoms (pain, numbness, weakness) |
| 12 | Yuan et al. [19] | 2020 | China | Comparative study (prospective) | 46 | 42.41 ± 7.06 (spinal endoscopy group), 46.04 ± 8.85 (ACDF group) | 36.4 (spinal endoscopy), 25 (ACDF) | 63.6 (spinal endoscopy), 75 (ACDF) | Not explicitly mentioned | Single or 2-level compressive lesions | NM | NM | NM | Upper and lower limb motor dysfunction, sensory dysfunction |
| 13 | Carr et al. [20] | 2020 | USA | Prospective study of cervical stenosis | 10 | 70.2 ± 5.0 | 60 | 40 | NM | C3–4 | NM | NM | NM | Severe cervical myelopathy (CSM) |
| 14 | Ji-jun et al. [21] | 2020 | China | Prospective cohort study | 81 | ACDF: 51.4 ± 8.2, PECD: 46.6 ± 8.8 | 28 (PECD), 11 (ACDF) | 27 (PECD), 15 (ACDF) | NM | C3–4, C4–5, C5–6, C6–7 | Failed conservative treatment > 3 mo | NM | NM | Radicular pain, sensory/motor loss |
| 15 | Haijun et al. [22] | 2020 | China | Retrospective | 106 | Mean ~61 (± 2.35–2.56) | ~50 | ~50 | ~9 Mo | C4–C5, C5–C6, C6–C7 | Not explicitly mentioned | NM | NM | Arm pain, sensory impairment, or motor function loss |
| 16 | Wang et al. [23] | 2021 | China | Retrospective cohort control study | 74 | 44.23 ± 8.02 (T-EMG), 46.92 ± 9.72 (IOM) | ~33 (T-EMG), ~41 (IOM) | ~67 (T-EMG), ~59 (IOM) | Not explicitly mentioned | C4–5, C5–6, C6–7 | NM | NM | NM | CSR, radiculopathy with arm pain and numbness |
| 17 | Tacconi et al. [24] | 2021 | Italy | Randomized study | 37 | 30–80 (median, 50) | 51 | 49 | > 6 | C4–C5, C5–C6, C6–C7 | NM | > 6 | NM | Unilateral radiculopathy due to foraminal stenosis |
| 18 | Yu et al. [25] | 2021 | China | Retrospective comparative cohort | 28 | 24–81 (mean, 40) | 33 (3.7 mm) 50 (6.9 mm) | Not specified | 7–48 (mean 14 for 3.7 mm, 16 for 6.9 mm) | C4–C5, C5–C6, C6–C7, C7–T1 | Not explicitly mentioned | Not explicitly mentioned | NM | Unilateral cervical spondylotic radiculopathy with radiating pain |
| 19 | Ran et al. [26] | 2021 | China | Prospective cohort study | 21 | 37–66 (mean, 49.9) | ~57 | ~43 | 0.3–60 Mo (mean, 10.4 mo) | Single-level CSM | NM | NM | NM | Intolerable pain, CSM confirmed by MRI and CT |
| 20 | Liu et al. [27] | 2021 | China | Retrospective, single-center study | 87 | Mean: 52.1 | 49 | 38 | NM | C4–5, C5–6, C6–7, C7–T1 | NM | > 12 | NM | Numbness, radicular pain, some motor dysfunction |
| 21 | Wu et al. [28] | 2021 | South Korea | Prospective, retrospective analysis | 25 | Mean 51.8 ± 8.9 | 36 | 64 | NM | C5–6, C6–7 | NM | > 6 | NM | NM |
| 22 | Ma et al. [29] | 2022 | China | Retrospective study | 127 | 44.5 ± 11.2 (ACDF), 46.5 ± 11.3 (PECF) | ~31 (ACDF), ~32 (PECF) | ~69 (ACDF), ~68 (PECF) | 25.3 ± 8.9 (PECF), 27.3 ± 9.2 (ACDF) | C3–4, C4–5, C5–6, C6–7 | Failed conservative treatment | At least 12 | NM | Radiculopathy with single-level cervical herniation |
| 23 | Gatam et al. [30] | 2022 | Indonesia | Prospective, single-arm study | 65 | 33–78 (mean, 45.6) | ~48 | ~52 | > 12 | C4–5, C5–6, C6–7 | 100 | > 12 | NM | Radicular arm pain |
| 24 | Zhong et al. [31] | 2022 | China | Retrospective | 34 | 54.75 ± 9.74 | ~56 | ~44 | 6.12 ± 2.36 Mo | C4–5, C5–6, C6–7 | NM | NM | NM | Severe unilateral upper limb pain |
| 25 | Kang et al. [32] | 2022 | Korea | Retrospective review | 65 | 53.74 ± 8.50 (PE), 52.68 ± 9.56 (BE) | Not specified | Not specified | > 6 conservative treatment | Single-level, unilateral foraminal disc disease | 100 | > 6 | NM | Cervical radiculopathy |
| 26 | Dalgic et al. [33] | 2022 | Turkey | Retrospective case series | 83 | 30–70 (MD group: 51.1, EAD group: 38.7) | 52.3 (MD), 63.4 (EAD) | 47.7 (MD), 37.6 (EAD) | NM | C3–C4, C4–C5, C5–C6, C6–C7, C7–T1 | NM | Minimum of 4 | NM | 61.9 (MD), 48.8 (EAD) |
| 27 | Shi et al. [34] | 2023 | China | Retrospective study | 22 | 49.6 ± 9.2 (range 36–78) | 7 (32) | 15 (68) | Not specified | C3–4, C4–5, C5–6, C6–7 | Failed conservative treatment | 6 | NM | Radicular symptoms due to foraminal bony stenosis |
| 28 | Kotheeranurak et al. [35] | 2024 | Thailand | Retrospective matched-pair comparison study | 60 | 38 ± 6.43 (CDR), 38 ± 3.23 (PECD) | 63 (CDR), 57 (PECD) | 37 (CDR), 43 (PECD) | NM | Unilateral cervical disc herniation | NM | NM | NM | Radicular pain, motor or sensory deficits |
| 29 | Li et al. [36] | 2024 | China | Retrospective, propensity score-matched | 138 (62 Endoscopic, 76 ACDF) | 63.44 ± 8.38 (endoscopic), 66.47 ± 8.59 (ACDF) | 45.2 (endoscopic), 44.7 (ACDF) | 54.8 (endoscopic), 55.3 (ACDF) | Disease duration: 20.98 ± 8.27 mo (endoscopic), 24.51 ± 7.72 mo (ACDF) | C3–7 | Not explicitly mentioned | Not provided | NM | Myelopathy, myeloradiculopathy, Radiculopathy |
| 30 | Lee et al. [37] | 2024 | Japan | Retrospective case series | 25 | Mean 57 (21–76) | 8 | 92 | Mean 10 mo (1–119 mo) | C4–5, C5–6 | Conservative treatment for ≥1 mo | 1 to 6 mo | NM | Cervical spondylotic amyotrophy (CSA), muscle atrophy |
NM, not mentioned; AFECD, anterior full endoscopic cervical discectomy; PFECD, Posterior Full Endoscopic Cervical Discectomy; FPCF, full percutaneous cervical foraminotomy; ACDF, anterior cervical discectomy and fusion; PECD, posterior endoscopic cervical discectomy; T-EMG, triggered electromyography; CSM, cervical spondylotic myelopathy; CSA, cervical spondylotic amyotrophy; IOM, intraoperative monitoring; PE, percutaneous endoscopic; BE, biportal endoscopic; VBD, ventral bony decompression; SDD, simple dorsal decompression; CSR, cervical spondylotic radiculopathy; MD, microdiscectomy, EAD, endoscope-assisted discectomy.
| No. | Study | Sample size (n) | Arm pain relief (%) | Occasional pain (%) | Neck pain reduction (VAS) | Mean operating time (min) | Intraoperative blood loss (mL) | Mean hospital stay (day) | Postoperative work disability (day) | Complication rate (%) | Revision rate (%) | Patient satisfaction (%) | Recurrence rate (%) | Neurologic deficit improvement (%) | Postoperative dysphagia (%) | Overall clinical success (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Ruetten et al. [5] | 175 | 87.4 | 9.2 | Significant reduction | 68 (ACDF), 28 (FPCF) | < 10 (ACDF), none (FPCF) | NM | 19 (FPCF), 34 (ACDF) | 3 (FPCF) | 4.7 (ACDF), 6.7 (FPCF) | 91 (ACDF), 96 (FPCF) | 6.7 (FPCF) | Significant reduction | Transient in 3 (ACDF) | Significant improvement |
| 2 | Kim et al. [6] | 3 | 90 improvement in 2 patients | NM | 3-4/10 to minimal | NM | NM | NM | 10 to 2 mo | None | None | Not explicitly mentioned | None | Triceps weakness improved to motor grade V/V | NM | Excellent (MacNab criteria) |
| 3 | Yang et al. [10] | 84 | Not provided | Not provided | Significant improvement | AFECD: 63.5, PFECD: 78.5 | Negligible | AFECD: 4.9, PFECD: 4.5 | NM | 4.8 overall | AFECD: 1, PFECD: 1 | Not provided | 3.6 | Not explicitly provided | NM | Favorable in both groups |
| 4 | Ye et al. [11] | 9 | Not provided | Not provided | 7.89 preop to 1.11 postop | 80 (mean) | None observed | 2.7 (mean) | NM | None | None | 7 Excellent, 2 good | NM | 100 (all patients) | Transient in 1 patient | 100 (all patients showed improvement) |
| 5 | Zheng et al. [12] | 252 | 86.7 | 13.3 | Significant reduction | 89.4 (range: 60–180) | 20.3 (range: 10–800) | 1 | NM | 1 | NM | 86.7 | 1 (epidural hematoma) | Transient in 2 patients | NM | 86.7 (MacNab criteria) |
| 6 | Wan et al. [13] | 25 | Significant | NM | Significant reduction | 90 (75–120) | None measurable | 3 | NM | None | 4 | 96 | NM | NM | None | 96 (22 excellent, 2 good) |
| 7 | Lee et al. [14] | 106 | NM | NM | 5.3 to 1.4 (24 months) | NM | NM | NM | NM | 2.8 | 1 | NM | NM | Improvement in 95 patients | Transient in 2.8 patients | Not explicitly mentioned |
| 8 | Yu et al. [15] | 30 | NM | NM | Significant improvement | 63.6 ± 13.5 (39–100) | NM | 3.8 ± 1.5 (1–7) | NM | 3 (1 patient) | None | 29 out of 30 patients satisfied | None | Significant improvement | NM | 29 out of 30 patients had a favorable outcome |
| 9 | Xiao et al. [16] | 84 | NM | NM | Reduction greater in group B at 1-, 3-, 7-day postsurgery | Group A: 74.48 ± 7.08, Group B: 66.00 ± 9.62 | NM | Group A: 3.86 ± 0.85, Group B: 3.24 ± 0.83 | NM | Group A: 10.0, Group B: 4.55 | NM | NM | NM | NM | NM | No significant difference (MacNab grading) |
| 10 | Shu et al. [17] | 32 | NM | NM | Reduced from 5.8 ± 1.7 to 1.1 ± 0.8 at 12 months | 56 ± 41.6 | < 10 | 3.2 ± 1.3 | NM | 3.12 (1 patient, transient thumb weakness) | None | 84.4 (excellent/good outcome) | NM | NM | None | 84.4 (Odom’s criteria: excellent/good) |
| 11 | Tong et al. [18] | 46 | VBD: 91.29 | SDD: 60.87 | Significant reduction | 129.39 ± 9.96 (VBD)/97.65 ± 7.54 (SDD) | NM | NM | NM | 4.3 (SDD) | NM | NM | 4.3 (SDD) | NM | NM | VBD: 91.29, SDD: 60.87 |
| 12 | Yuan et al. [19] | 46 | NM | NM | NM | 70.23 ± 10.91 (spinal endoscopy), 92.29 ± 13.13 (ACDF) | 30.00 ± 7.30 (spinal endoscopy), 132.38 ± 14.33 (ACDF) | 4.23 ± 1.11 (spinal endoscopy), 8.21 ± 1.50 (ACDF) | NM | NM | 4.5 (spinal endoscopy), 0 (ACDF) | 81.8 (spinal endoscopy), 83.3 (ACDF) | NM | JOA improvement: 67.59 (spinal endoscopy), 69.37 (ACDF) | NM | 81.8 (spinal endoscopy), 83.3 (ACDF) |
| 13 | Carr et al. [20] | 10 | NM | NM | 5.8 ± 0.9 (preop), 2.9 ± 0.6 (postop) | 128 ± 18.4 | < 10 | 1.2 ± 0.2 | NM | Transient neurological deficit in 1 patient (10) | None | NM | NM | Improved mJOA scores from 11.4 ± 0.9 to 14.6 ± 1.0 | None | Significant improvement |
| 14 | Ji-jun et al. [21] | 81 | Not specifically mentioned | NM | Significant reduction | ACDF: 59.2 ± 10.2, PECD: 95.3 ± 13.1 | ACDF: 71.4 ± 14.2, PECD: none | ACDF: 5.5 ± 1.1, PECD: 3.8 ± 0.9 | NM | 9.3 | None | NM | NM | Significant improvement (PECD) | 10.5 (ACDF) | NM |
| 15 | Haijun et al. [22] | 106 | Not provided | Not provided | Significant improvement | 60.47 (delta), 75.46 (key-hole) | 20.47 (delta), 20.33 (key-hole) | 4.45–4.66 | NM | 5.35 (delta), 10 (key-hole) | NM | 96.4 (delta), 94.0 (key-hole) | 1 Recurrence (delta) | Improved | NM | Not provided |
| 16 | Wang et al. [23] | 74 | Not explicitly mentioned | NM | Reduced significantly in both groups (p < 0.05) | 108.29 ± 11.44 (T-EMG), 110.13 ± 12.70 (IOM) | NM | 5.66 ± 0.99 (T-EMG), 7.10 ± 1.43 (IOM) | NM | 1/35 (T-EMG), 7/39 (IOM) | NM | 91.43 (T-EMG), 89.7 (IOM) | NM | Significant improvement | NM | NM |
| 17 | Tacconi et al. [24] | 37 | NM | NM | FEPCF: 3.6 (mean); OPCF: 6.1 | 62 (FEPCF), 67.5 (OPCF) | < 50 cc (FEPCF), 50–120 cc (OPCF) | NM | NM | FEPCF: 24 (transient dysesthesia) | 1 case (FEPCF, ACDF revision) | Not explicitly mentioned | Not explicitly mentioned | NM | NM | Decrease in arm pain score by 3 points |
| 18 | Yu et al. [25] | 28 | Not explicitly mentioned | NM | Significant reduction in both groups | 76.5 (3.7)/61.5 (6.9) | Negligible for both groups | 5.1(3.7mm)/4.8 (6.9 mm) | NM | 3.7 | 0 | Excellent/good recovery for both groups | 0 | Not explicitly mentioned | NM | No significant difference in outcomes |
| 19 | Ran et al. [26] | 21 | Significant reduction (VAS decrease from 5.5 to 0.4) | NM | Significant reduction | 169.3 ± 49.8 | Minimal, controlled | NM | NM | 9.5 (2 patients had fair outcomes) | None | 90.5 | None | Significant improvement | None | 90.5 (good or excellent) |
| 20 | Liu et al. [27] | 87 | Significant | NM | From 7 to 3 (1 yr) | 74.3 | 30.1 | 4.7 | NM | None reported | NM | NM | None reported | NM | None reported | Significant improvement |
| 21 | Wu et al. [28] | 25 | NM | NM | Mean improvement of 5.08 ± 1.75 | 52.6 | NM | NM | NM | 12 | 0 | 92 (MacNab criteria: good and excellent results) | 4 (one case) | 2 cases of motor deficits recovered within 1 year | NM | NM |
| 22 | Ma et al. [29] | 127 | Not explicitly mentioned | NM | Significant reduction | 66.8 ± 6.8 (PECF), 59.4 ± 9.1 (ACDF) | NM | 3.7 ± 1.3 (PECF), 6.8 ± 1.5 (ACDF) | NM | 17.2 (ACDF), 3.4 (PECF) | NM | NM | NM | Significant improvement | 3.4 (ACDF) | NM |
| 23 | Gatam et al. [30] | 65 | Significant VAS reduction | NM | No neck pain | 47.8 | ~23.6 | 1.5 | NM | 6.15 hypesthesia | NM | Good to excellent results (MacNab) | NM | Fair in 5 patients (hypesthesia) | NM | Good to excellent (MacNab criteria) |
| 24 | Zhong et al. [31] | 34 | NM | NM | 7.25→0.25 (2 years) | 81.18 ± 10.87 | None | 4.52 ± 1.22 | NM | 0 | 0 | 91.17 (excellent+good) | 0 | NM | 0 | 91.17 (excellent+good) |
| 25 | Kang et al. [32] | 65 | Significant improvement | NM | VAS-arm and VAS-neck both improved | 78.61 ± 14.47 (PE), 70.97 ± 12.00 (BE) | NM | 2.16 ± 1.44 (PE), 2.48 ± 1.23 (BE) | NM | 3 (PE), 3 (BE) | 3.1 (PE), 3 (BE) | 91.7 (PE), 87.9 (BE) | NM | Significant improvement | NM | Excellent or good (PE: 91.7, BE: 87.9) |
| 26 | Dalgic et al. [33] | 83 | NM | NM | Preop Neck: 7.74 | 74.39 (MD), 81.4 (EAD) | 88.29 (MD), 81.5 (EAD) | NM | NM | 7.1 (MD), 7.3 (EAD) | 0 (MD), 1 (EAD) | Not explicitly mentioned | 2.4 (EAD) | Not explicitly mentioned | NM | 90.3 |
| Postop Neck: 2.23 | ||||||||||||||||
| 27 | Shi et al. [34] | 22 | Not specified | Not specified | Preop 8.09 ± 1.24; 1 wk: 2.14 ± 1.83 | 141.6 ± 13.7 | NM | 6.0 ± 2.5 | NM | 1 case (4.5 hematoma) | NM | NM | NM | Significant improvement | NM | NM |
| 28 | Kotheeranurak et al. [35] | 60 | Not specifically mentioned | NM | Improved in both groups (p < 0.05) | 42.3 ± 13.1 (CDR), 48.3 ± 20.1 (PECD) | 20.1 ± 10.6 (CDR), 5.4 ± 15.2 (PECD) | 3.2 ± 2.6 (CDR), 1.2 ± 1.5 (PECD) | 12.7 ± 10.4 (CDR), 5.2 ± 8.5 (PECD) | 5 (both groups) | None | 86 rated “good” or “excellent” | NM | Significant improvement in both groups | 10 (CDR), 0 (PECD) | 87 (excellent or good) |
| 29 | Li et al. [36] | 138 (62 Endoscopic, 76 ACDF) | Not explicitly mentioned | NM | Significant reduction in both groups | 85.43 ± 5.16 (endoscopic), 98.48 ± 7.84 (ACDF) | 8.29 ± 2.68 (endoscopic), 50.40 ± 4.46 (ACDF) | 6.14 ± 0.87 (endoscopic), 8.07 ± 0.84 (ACDF) | NM | Neurological dysfunction: 1 (Endoscopic), 2 (ACDF); CSF leakage: 2 (endoscopic, 2 ACDF) | Revision: 0 (endoscopic), 1 (ACDF) | 90.48 (endoscopic), 88.10 (ACDF) | NM | Not explicitly mentioned | Dysphagia: 1 (ACDF) | 90.48 (endoscopic), 88.10 (ACDF) |
| 30 | Lee et al. [37] | 25 | NM | NM | NM | 86 (C4/5), 72 (C5/6) | NM | 2–25 (mean 4.2) | NM | Tiny epineural injury in 1 case | NM | NM | NM | Significant improvement (84) | NM | Improvement in 84 of cases |
NM, not mentioned; AFECD, anterior full endoscopic cervical discectomy; PFECD, Posterior Full Endoscopic Cervical Discectomy; FPCF, full percutaneous cervical foraminotomy; ACDF, anterior cervical discectomy and fusion; PECD, posterior endoscopic cervical discectomy; T-EMG, triggered electromyography; IOM, intraoperative monitoring; PE, percutaneous endoscopic; BE, biportal endoscopic; VBD, ventral bony decompression; SDD, simple dorsal decompression; VAS, visual analogue scale; JOA, Japanese Orthopaedic Association; mJOA, modified JOA; FEPCF, Full-endoscopic posterior cervical foraminotomy; MD, microdiscectomy, EAD, endoscope-assisted discectomy; OPCF, open posterior cervical foraminotomy; PECF, percutaneous endoscopic cervical foraminotomy; CDR, cervical disc replacement.
| Study No. | Study | Confounding | Selection of participants | Classification of interventions | Deviations from intended interventions | Missing data | Measurement of outcomes | Selection of reported results | Overall |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Kim et al. [6] | Serious | Moderate | Low | Low | Low | Moderate | Low | Serious |
| 2 | Yang et al. [10] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 3 | Ye et al. [11] | Serious | Moderate | Low | Low | Low | Moderate | Low | Serious |
| 4 | Zheng et al. [12] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 5 | Wan et al. [13] | Serious | Moderate | Low | Low | Low | Moderate | Low | Serious |
| 6 | Lee et al. [14] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 7 | Yu et al. [15] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 8 | Xiao et al. [16] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 9 | Shu et al. [17] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 10 | Tong et al. [18] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 11 | Yuan et al. [19] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 12 | Carr et al. [20] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 13 | Ji-jun et al. [21] | Low | Low | Low | Low | Low | Low | Low | Low |
| 14 | Haijun et al. [22] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 15 | Wang et al. [23] | Low | Low | Low | Low | Low | Low | Low | Low |
| 16 | Yu et al. [25] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 17 | Ran et al. [26] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 18 | Liu et al. [27] | Moderate | Low | Low | Low | Moderate | Moderate | Low | Moderate |
| 19 | Wu et al. [28] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 20 | Ma et al. [29] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 21 | Gatam et al. [30] | Low | Low | Low | Low | Low | Low | Low | Low |
| 22 | Zhong et al. [31] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 23 | Kang et al. [32] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 24 | Dalgic et al. [33] | Low | Low | Low | Low | Low | Low | Low | Low |
| 25 | Shi et al. [34] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 26 | Kotheeranurak et al. [35] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 27 | Li et al. [36] | Low | Low | Low | Low | Low | Low | Low | Low |
| 28 | Lee et al. [37] | Low | Low | Low | Low | Low | Low | Low | Low |
| Study | Randomization | Deviation from the intended intervention | Missing outcome data | Measurement of the outcome | Selection of the report results | Overall |
|---|---|---|---|---|---|---|
| Ruetten et al. [5] | Low | Low | Low | Low | Low | Low |
| Tacconi et al. [24] | Low | Low | Low | Low | Low | Low |
| No. | Study | Published year | Nationality | Type of study | Sample size (n) | Age (yr) | Female (%) | Male (%) | Symptom duration (wk) | Level of disc herniation | Previous conservative treatment (%) | Conservative treatment duration (wk) | Physical occupation (%) | Neurological deficits |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Ruetten et al. [5] | 2008 | Germany | Prospective, randomized, controlled | 175 | 27–62 (mean, 43) | 66 | 34 | 5 Days to 8 months (mean, 94 days) | C2–C3–C7–T1 | 85 | 10 | NM | Intolerable radicular pain or neurologic deficits |
| 2 | Kim et al. [6] | 2009 | South Korea | Prospective | 3 | 42, 46, 50 | 0 | 100 | 2 to 2 yr | C6–7 | NM | NM | 100 (all soldiers) | Triceps weakness, radicular pain, neck pain |
| 3 | Yang et al. [10] | 2014 | China | Retrospective comparative cohort | 84 | AFECD: 41.3 (28–57), PFECD: 40.5 (32–68) | AFECD: 38, PFECD: 33 | Not provided | AFECD: 6–46, PFECD: 2–48 | C3–4, C4–5, C5–6, C6–7 | Not explicitly mentioned | Minimum 4 | NM | Radiculopathy and/or myelopathy |
| 4 | Ye et al. [11] | 2017 | China | Clinical observation | 9 | 39–56 (mean, 46) | 33 | 66 | 2–26 (mean, 16) | C4–7 | 77 | 12 | NM | Intolerable radicular pain or neurologic deficits |
| 5 | Zheng et al. [12] | 2018 | China | Retrospective review of PECD cases | 252 | NM | 129/252 (51) | 120/252 (48) | NM | C3–4, C4–5, C5–6, C6–7 | 100 | 12 | NM | Radicular pain, single-level foraminal soft disc herniation or foraminal stenosis |
| 6 | Wan et al. [13] | 2018 | China | Prospective, clinical study | 25 | 27–57 (mean, 38) | 44 | 56 | 2 to 10 Mo (mean, 5.5) | C4–5, C5–6, C6–7, C7–T1 | NM | > 6 | NM | Arm/shoulder radicular pain, upper-extremity numbness, muscle weakness, weakened tendon reflex |
| 7 | Lee et al. [14] | 2018 | South Korea | Retrospective review | 106 | Mean: 49.2 (SD, 10.8) | 35.9 | 64.1 | Median: 2.3 mo | C5–6 | NM | NM | NM | Motor weakness in 72% of patients |
| 8 | Yu et al. [15] | 2019 | China | Retrospective observational study | 30 | 47.7 ± 12.5 (26–79) | 43.8 | 56.2 | Mean 19.5 mo | C3–4, C4–5, C5–6, C6–7 | NM | At least 4 | NM | Radiculopathy, myelopathy (Nurick grade ≤ 3) |
| 9 | Xiao et al. [16] | 2019 | China | Retrospective comparative study | 84 | 52.9 ± 14.3 (group A), 55.4 ± 12.3 (group B) | Group A (22) | Group A (18) | 11.2±5.6 mo (group A), 10.8 ± 5.8 mo (group B) | C4–5, C5–6, C6–7 | NM | NM | NM | Unilateral cervical radiculopathy with arm pain or loss of sensory/motor function |
| Group A: posterior percutaneous endoscopic cervical discectomy (P–PECD) | Group B (24) | Group B (20) | ||||||||||||
| Group B: P–PECD combined with partial pediculectomy | ||||||||||||||
| 10 | Shu et al. [17] | 2019 | China | Retrospective study | 32 | Mean: 63.0 ± 10.5 | 56.25 | 43.75 | At least 12 | C4–5, C5–6, C6–7 | All patients | Not specified | NM | Radicular pain with foraminal stenosis |
| 11 | Tong et al. [18] | 2020 | China | Retrospective cohort study | 46 | 54.22 ± 10.52 (VBD)/57.48 ± 7.80 (SDD) | 47.8 (VBD) | 52.2 (VBD) | 3 Mo (minimum) | C5–6, C6–7 | 100 (ineffective conservative treatment for 3 months) | NM | NM | Unilateral root symptoms (pain, numbness, weakness) |
| 12 | Yuan et al. [19] | 2020 | China | Comparative study (prospective) | 46 | 42.41 ± 7.06 (spinal endoscopy group), 46.04 ± 8.85 (ACDF group) | 36.4 (spinal endoscopy), 25 (ACDF) | 63.6 (spinal endoscopy), 75 (ACDF) | Not explicitly mentioned | Single or 2-level compressive lesions | NM | NM | NM | Upper and lower limb motor dysfunction, sensory dysfunction |
| 13 | Carr et al. [20] | 2020 | USA | Prospective study of cervical stenosis | 10 | 70.2 ± 5.0 | 60 | 40 | NM | C3–4 | NM | NM | NM | Severe cervical myelopathy (CSM) |
| 14 | Ji-jun et al. [21] | 2020 | China | Prospective cohort study | 81 | ACDF: 51.4 ± 8.2, PECD: 46.6 ± 8.8 | 28 (PECD), 11 (ACDF) | 27 (PECD), 15 (ACDF) | NM | C3–4, C4–5, C5–6, C6–7 | Failed conservative treatment > 3 mo | NM | NM | Radicular pain, sensory/motor loss |
| 15 | Haijun et al. [22] | 2020 | China | Retrospective | 106 | Mean ~61 (± 2.35–2.56) | ~50 | ~50 | ~9 Mo | C4–C5, C5–C6, C6–C7 | Not explicitly mentioned | NM | NM | Arm pain, sensory impairment, or motor function loss |
| 16 | Wang et al. [23] | 2021 | China | Retrospective cohort control study | 74 | 44.23 ± 8.02 (T-EMG), 46.92 ± 9.72 (IOM) | ~33 (T-EMG), ~41 (IOM) | ~67 (T-EMG), ~59 (IOM) | Not explicitly mentioned | C4–5, C5–6, C6–7 | NM | NM | NM | CSR, radiculopathy with arm pain and numbness |
| 17 | Tacconi et al. [24] | 2021 | Italy | Randomized study | 37 | 30–80 (median, 50) | 51 | 49 | > 6 | C4–C5, C5–C6, C6–C7 | NM | > 6 | NM | Unilateral radiculopathy due to foraminal stenosis |
| 18 | Yu et al. [25] | 2021 | China | Retrospective comparative cohort | 28 | 24–81 (mean, 40) | 33 (3.7 mm) 50 (6.9 mm) | Not specified | 7–48 (mean 14 for 3.7 mm, 16 for 6.9 mm) | C4–C5, C5–C6, C6–C7, C7–T1 | Not explicitly mentioned | Not explicitly mentioned | NM | Unilateral cervical spondylotic radiculopathy with radiating pain |
| 19 | Ran et al. [26] | 2021 | China | Prospective cohort study | 21 | 37–66 (mean, 49.9) | ~57 | ~43 | 0.3–60 Mo (mean, 10.4 mo) | Single-level CSM | NM | NM | NM | Intolerable pain, CSM confirmed by MRI and CT |
| 20 | Liu et al. [27] | 2021 | China | Retrospective, single-center study | 87 | Mean: 52.1 | 49 | 38 | NM | C4–5, C5–6, C6–7, C7–T1 | NM | > 12 | NM | Numbness, radicular pain, some motor dysfunction |
| 21 | Wu et al. [28] | 2021 | South Korea | Prospective, retrospective analysis | 25 | Mean 51.8 ± 8.9 | 36 | 64 | NM | C5–6, C6–7 | NM | > 6 | NM | NM |
| 22 | Ma et al. [29] | 2022 | China | Retrospective study | 127 | 44.5 ± 11.2 (ACDF), 46.5 ± 11.3 (PECF) | ~31 (ACDF), ~32 (PECF) | ~69 (ACDF), ~68 (PECF) | 25.3 ± 8.9 (PECF), 27.3 ± 9.2 (ACDF) | C3–4, C4–5, C5–6, C6–7 | Failed conservative treatment | At least 12 | NM | Radiculopathy with single-level cervical herniation |
| 23 | Gatam et al. [30] | 2022 | Indonesia | Prospective, single-arm study | 65 | 33–78 (mean, 45.6) | ~48 | ~52 | > 12 | C4–5, C5–6, C6–7 | 100 | > 12 | NM | Radicular arm pain |
| 24 | Zhong et al. [31] | 2022 | China | Retrospective | 34 | 54.75 ± 9.74 | ~56 | ~44 | 6.12 ± 2.36 Mo | C4–5, C5–6, C6–7 | NM | NM | NM | Severe unilateral upper limb pain |
| 25 | Kang et al. [32] | 2022 | Korea | Retrospective review | 65 | 53.74 ± 8.50 (PE), 52.68 ± 9.56 (BE) | Not specified | Not specified | > 6 conservative treatment | Single-level, unilateral foraminal disc disease | 100 | > 6 | NM | Cervical radiculopathy |
| 26 | Dalgic et al. [33] | 2022 | Turkey | Retrospective case series | 83 | 30–70 (MD group: 51.1, EAD group: 38.7) | 52.3 (MD), 63.4 (EAD) | 47.7 (MD), 37.6 (EAD) | NM | C3–C4, C4–C5, C5–C6, C6–C7, C7–T1 | NM | Minimum of 4 | NM | 61.9 (MD), 48.8 (EAD) |
| 27 | Shi et al. [34] | 2023 | China | Retrospective study | 22 | 49.6 ± 9.2 (range 36–78) | 7 (32) | 15 (68) | Not specified | C3–4, C4–5, C5–6, C6–7 | Failed conservative treatment | 6 | NM | Radicular symptoms due to foraminal bony stenosis |
| 28 | Kotheeranurak et al. [35] | 2024 | Thailand | Retrospective matched-pair comparison study | 60 | 38 ± 6.43 (CDR), 38 ± 3.23 (PECD) | 63 (CDR), 57 (PECD) | 37 (CDR), 43 (PECD) | NM | Unilateral cervical disc herniation | NM | NM | NM | Radicular pain, motor or sensory deficits |
| 29 | Li et al. [36] | 2024 | China | Retrospective, propensity score-matched | 138 (62 Endoscopic, 76 ACDF) | 63.44 ± 8.38 (endoscopic), 66.47 ± 8.59 (ACDF) | 45.2 (endoscopic), 44.7 (ACDF) | 54.8 (endoscopic), 55.3 (ACDF) | Disease duration: 20.98 ± 8.27 mo (endoscopic), 24.51 ± 7.72 mo (ACDF) | C3–7 | Not explicitly mentioned | Not provided | NM | Myelopathy, myeloradiculopathy, Radiculopathy |
| 30 | Lee et al. [37] | 2024 | Japan | Retrospective case series | 25 | Mean 57 (21–76) | 8 | 92 | Mean 10 mo (1–119 mo) | C4–5, C5–6 | Conservative treatment for ≥1 mo | 1 to 6 mo | NM | Cervical spondylotic amyotrophy (CSA), muscle atrophy |
| No. | Study | Sample size (n) | Arm pain relief (%) | Occasional pain (%) | Neck pain reduction (VAS) | Mean operating time (min) | Intraoperative blood loss (mL) | Mean hospital stay (day) | Postoperative work disability (day) | Complication rate (%) | Revision rate (%) | Patient satisfaction (%) | Recurrence rate (%) | Neurologic deficit improvement (%) | Postoperative dysphagia (%) | Overall clinical success (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Ruetten et al. [5] | 175 | 87.4 | 9.2 | Significant reduction | 68 (ACDF), 28 (FPCF) | < 10 (ACDF), none (FPCF) | NM | 19 (FPCF), 34 (ACDF) | 3 (FPCF) | 4.7 (ACDF), 6.7 (FPCF) | 91 (ACDF), 96 (FPCF) | 6.7 (FPCF) | Significant reduction | Transient in 3 (ACDF) | Significant improvement |
| 2 | Kim et al. [6] | 3 | 90 improvement in 2 patients | NM | 3-4/10 to minimal | NM | NM | NM | 10 to 2 mo | None | None | Not explicitly mentioned | None | Triceps weakness improved to motor grade V/V | NM | Excellent (MacNab criteria) |
| 3 | Yang et al. [10] | 84 | Not provided | Not provided | Significant improvement | AFECD: 63.5, PFECD: 78.5 | Negligible | AFECD: 4.9, PFECD: 4.5 | NM | 4.8 overall | AFECD: 1, PFECD: 1 | Not provided | 3.6 | Not explicitly provided | NM | Favorable in both groups |
| 4 | Ye et al. [11] | 9 | Not provided | Not provided | 7.89 preop to 1.11 postop | 80 (mean) | None observed | 2.7 (mean) | NM | None | None | 7 Excellent, 2 good | NM | 100 (all patients) | Transient in 1 patient | 100 (all patients showed improvement) |
| 5 | Zheng et al. [12] | 252 | 86.7 | 13.3 | Significant reduction | 89.4 (range: 60–180) | 20.3 (range: 10–800) | 1 | NM | 1 | NM | 86.7 | 1 (epidural hematoma) | Transient in 2 patients | NM | 86.7 (MacNab criteria) |
| 6 | Wan et al. [13] | 25 | Significant | NM | Significant reduction | 90 (75–120) | None measurable | 3 | NM | None | 4 | 96 | NM | NM | None | 96 (22 excellent, 2 good) |
| 7 | Lee et al. [14] | 106 | NM | NM | 5.3 to 1.4 (24 months) | NM | NM | NM | NM | 2.8 | 1 | NM | NM | Improvement in 95 patients | Transient in 2.8 patients | Not explicitly mentioned |
| 8 | Yu et al. [15] | 30 | NM | NM | Significant improvement | 63.6 ± 13.5 (39–100) | NM | 3.8 ± 1.5 (1–7) | NM | 3 (1 patient) | None | 29 out of 30 patients satisfied | None | Significant improvement | NM | 29 out of 30 patients had a favorable outcome |
| 9 | Xiao et al. [16] | 84 | NM | NM | Reduction greater in group B at 1-, 3-, 7-day postsurgery | Group A: 74.48 ± 7.08, Group B: 66.00 ± 9.62 | NM | Group A: 3.86 ± 0.85, Group B: 3.24 ± 0.83 | NM | Group A: 10.0, Group B: 4.55 | NM | NM | NM | NM | NM | No significant difference (MacNab grading) |
| 10 | Shu et al. [17] | 32 | NM | NM | Reduced from 5.8 ± 1.7 to 1.1 ± 0.8 at 12 months | 56 ± 41.6 | < 10 | 3.2 ± 1.3 | NM | 3.12 (1 patient, transient thumb weakness) | None | 84.4 (excellent/good outcome) | NM | NM | None | 84.4 (Odom’s criteria: excellent/good) |
| 11 | Tong et al. [18] | 46 | VBD: 91.29 | SDD: 60.87 | Significant reduction | 129.39 ± 9.96 (VBD)/97.65 ± 7.54 (SDD) | NM | NM | NM | 4.3 (SDD) | NM | NM | 4.3 (SDD) | NM | NM | VBD: 91.29, SDD: 60.87 |
| 12 | Yuan et al. [19] | 46 | NM | NM | NM | 70.23 ± 10.91 (spinal endoscopy), 92.29 ± 13.13 (ACDF) | 30.00 ± 7.30 (spinal endoscopy), 132.38 ± 14.33 (ACDF) | 4.23 ± 1.11 (spinal endoscopy), 8.21 ± 1.50 (ACDF) | NM | NM | 4.5 (spinal endoscopy), 0 (ACDF) | 81.8 (spinal endoscopy), 83.3 (ACDF) | NM | JOA improvement: 67.59 (spinal endoscopy), 69.37 (ACDF) | NM | 81.8 (spinal endoscopy), 83.3 (ACDF) |
| 13 | Carr et al. [20] | 10 | NM | NM | 5.8 ± 0.9 (preop), 2.9 ± 0.6 (postop) | 128 ± 18.4 | < 10 | 1.2 ± 0.2 | NM | Transient neurological deficit in 1 patient (10) | None | NM | NM | Improved mJOA scores from 11.4 ± 0.9 to 14.6 ± 1.0 | None | Significant improvement |
| 14 | Ji-jun et al. [21] | 81 | Not specifically mentioned | NM | Significant reduction | ACDF: 59.2 ± 10.2, PECD: 95.3 ± 13.1 | ACDF: 71.4 ± 14.2, PECD: none | ACDF: 5.5 ± 1.1, PECD: 3.8 ± 0.9 | NM | 9.3 | None | NM | NM | Significant improvement (PECD) | 10.5 (ACDF) | NM |
| 15 | Haijun et al. [22] | 106 | Not provided | Not provided | Significant improvement | 60.47 (delta), 75.46 (key-hole) | 20.47 (delta), 20.33 (key-hole) | 4.45–4.66 | NM | 5.35 (delta), 10 (key-hole) | NM | 96.4 (delta), 94.0 (key-hole) | 1 Recurrence (delta) | Improved | NM | Not provided |
| 16 | Wang et al. [23] | 74 | Not explicitly mentioned | NM | Reduced significantly in both groups (p < 0.05) | 108.29 ± 11.44 (T-EMG), 110.13 ± 12.70 (IOM) | NM | 5.66 ± 0.99 (T-EMG), 7.10 ± 1.43 (IOM) | NM | 1/35 (T-EMG), 7/39 (IOM) | NM | 91.43 (T-EMG), 89.7 (IOM) | NM | Significant improvement | NM | NM |
| 17 | Tacconi et al. [24] | 37 | NM | NM | FEPCF: 3.6 (mean); OPCF: 6.1 | 62 (FEPCF), 67.5 (OPCF) | < 50 cc (FEPCF), 50–120 cc (OPCF) | NM | NM | FEPCF: 24 (transient dysesthesia) | 1 case (FEPCF, ACDF revision) | Not explicitly mentioned | Not explicitly mentioned | NM | NM | Decrease in arm pain score by 3 points |
| 18 | Yu et al. [25] | 28 | Not explicitly mentioned | NM | Significant reduction in both groups | 76.5 (3.7)/61.5 (6.9) | Negligible for both groups | 5.1(3.7mm)/4.8 (6.9 mm) | NM | 3.7 | 0 | Excellent/good recovery for both groups | 0 | Not explicitly mentioned | NM | No significant difference in outcomes |
| 19 | Ran et al. [26] | 21 | Significant reduction (VAS decrease from 5.5 to 0.4) | NM | Significant reduction | 169.3 ± 49.8 | Minimal, controlled | NM | NM | 9.5 (2 patients had fair outcomes) | None | 90.5 | None | Significant improvement | None | 90.5 (good or excellent) |
| 20 | Liu et al. [27] | 87 | Significant | NM | From 7 to 3 (1 yr) | 74.3 | 30.1 | 4.7 | NM | None reported | NM | NM | None reported | NM | None reported | Significant improvement |
| 21 | Wu et al. [28] | 25 | NM | NM | Mean improvement of 5.08 ± 1.75 | 52.6 | NM | NM | NM | 12 | 0 | 92 (MacNab criteria: good and excellent results) | 4 (one case) | 2 cases of motor deficits recovered within 1 year | NM | NM |
| 22 | Ma et al. [29] | 127 | Not explicitly mentioned | NM | Significant reduction | 66.8 ± 6.8 (PECF), 59.4 ± 9.1 (ACDF) | NM | 3.7 ± 1.3 (PECF), 6.8 ± 1.5 (ACDF) | NM | 17.2 (ACDF), 3.4 (PECF) | NM | NM | NM | Significant improvement | 3.4 (ACDF) | NM |
| 23 | Gatam et al. [30] | 65 | Significant VAS reduction | NM | No neck pain | 47.8 | ~23.6 | 1.5 | NM | 6.15 hypesthesia | NM | Good to excellent results (MacNab) | NM | Fair in 5 patients (hypesthesia) | NM | Good to excellent (MacNab criteria) |
| 24 | Zhong et al. [31] | 34 | NM | NM | 7.25→0.25 (2 years) | 81.18 ± 10.87 | None | 4.52 ± 1.22 | NM | 0 | 0 | 91.17 (excellent+good) | 0 | NM | 0 | 91.17 (excellent+good) |
| 25 | Kang et al. [32] | 65 | Significant improvement | NM | VAS-arm and VAS-neck both improved | 78.61 ± 14.47 (PE), 70.97 ± 12.00 (BE) | NM | 2.16 ± 1.44 (PE), 2.48 ± 1.23 (BE) | NM | 3 (PE), 3 (BE) | 3.1 (PE), 3 (BE) | 91.7 (PE), 87.9 (BE) | NM | Significant improvement | NM | Excellent or good (PE: 91.7, BE: 87.9) |
| 26 | Dalgic et al. [33] | 83 | NM | NM | Preop Neck: 7.74 | 74.39 (MD), 81.4 (EAD) | 88.29 (MD), 81.5 (EAD) | NM | NM | 7.1 (MD), 7.3 (EAD) | 0 (MD), 1 (EAD) | Not explicitly mentioned | 2.4 (EAD) | Not explicitly mentioned | NM | 90.3 |
| Postop Neck: 2.23 | ||||||||||||||||
| 27 | Shi et al. [34] | 22 | Not specified | Not specified | Preop 8.09 ± 1.24; 1 wk: 2.14 ± 1.83 | 141.6 ± 13.7 | NM | 6.0 ± 2.5 | NM | 1 case (4.5 hematoma) | NM | NM | NM | Significant improvement | NM | NM |
| 28 | Kotheeranurak et al. [35] | 60 | Not specifically mentioned | NM | Improved in both groups (p < 0.05) | 42.3 ± 13.1 (CDR), 48.3 ± 20.1 (PECD) | 20.1 ± 10.6 (CDR), 5.4 ± 15.2 (PECD) | 3.2 ± 2.6 (CDR), 1.2 ± 1.5 (PECD) | 12.7 ± 10.4 (CDR), 5.2 ± 8.5 (PECD) | 5 (both groups) | None | 86 rated “good” or “excellent” | NM | Significant improvement in both groups | 10 (CDR), 0 (PECD) | 87 (excellent or good) |
| 29 | Li et al. [36] | 138 (62 Endoscopic, 76 ACDF) | Not explicitly mentioned | NM | Significant reduction in both groups | 85.43 ± 5.16 (endoscopic), 98.48 ± 7.84 (ACDF) | 8.29 ± 2.68 (endoscopic), 50.40 ± 4.46 (ACDF) | 6.14 ± 0.87 (endoscopic), 8.07 ± 0.84 (ACDF) | NM | Neurological dysfunction: 1 (Endoscopic), 2 (ACDF); CSF leakage: 2 (endoscopic, 2 ACDF) | Revision: 0 (endoscopic), 1 (ACDF) | 90.48 (endoscopic), 88.10 (ACDF) | NM | Not explicitly mentioned | Dysphagia: 1 (ACDF) | 90.48 (endoscopic), 88.10 (ACDF) |
| 30 | Lee et al. [37] | 25 | NM | NM | NM | 86 (C4/5), 72 (C5/6) | NM | 2–25 (mean 4.2) | NM | Tiny epineural injury in 1 case | NM | NM | NM | Significant improvement (84) | NM | Improvement in 84 of cases |
| Study No. | Study | Confounding | Selection of participants | Classification of interventions | Deviations from intended interventions | Missing data | Measurement of outcomes | Selection of reported results | Overall |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Kim et al. [6] | Serious | Moderate | Low | Low | Low | Moderate | Low | Serious |
| 2 | Yang et al. [10] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 3 | Ye et al. [11] | Serious | Moderate | Low | Low | Low | Moderate | Low | Serious |
| 4 | Zheng et al. [12] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 5 | Wan et al. [13] | Serious | Moderate | Low | Low | Low | Moderate | Low | Serious |
| 6 | Lee et al. [14] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 7 | Yu et al. [15] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 8 | Xiao et al. [16] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 9 | Shu et al. [17] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 10 | Tong et al. [18] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 11 | Yuan et al. [19] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 12 | Carr et al. [20] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 13 | Ji-jun et al. [21] | Low | Low | Low | Low | Low | Low | Low | Low |
| 14 | Haijun et al. [22] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 15 | Wang et al. [23] | Low | Low | Low | Low | Low | Low | Low | Low |
| 16 | Yu et al. [25] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 17 | Ran et al. [26] | Moderate | Moderate | Low | Low | Low | Moderate | Low | Moderate |
| 18 | Liu et al. [27] | Moderate | Low | Low | Low | Moderate | Moderate | Low | Moderate |
| 19 | Wu et al. [28] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 20 | Ma et al. [29] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 21 | Gatam et al. [30] | Low | Low | Low | Low | Low | Low | Low | Low |
| 22 | Zhong et al. [31] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 23 | Kang et al. [32] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 24 | Dalgic et al. [33] | Low | Low | Low | Low | Low | Low | Low | Low |
| 25 | Shi et al. [34] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 26 | Kotheeranurak et al. [35] | Moderate | Low | Low | Low | Low | Low | Low | Moderate |
| 27 | Li et al. [36] | Low | Low | Low | Low | Low | Low | Low | Low |
| 28 | Lee et al. [37] | Low | Low | Low | Low | Low | Low | Low | Low |
| Study | Randomization | Deviation from the intended intervention | Missing outcome data | Measurement of the outcome | Selection of the report results | Overall |
|---|---|---|---|---|---|---|
| Ruetten et al. [5] | Low | Low | Low | Low | Low | Low |
| Tacconi et al. [24] | Low | Low | Low | Low | Low | Low |
| Metric | Original | Trimmed (excluding extreme values) | Detailed/complications |
|---|---|---|---|
| Pain relief (%) | 87.89 ± 17.30 | 90.84 ± 4.51 | - |
| Complication rate (%) | 4.19 ± 3.20 | 4.29 ± 3.12 | Neurological deficits, dysphagia, hematoma and infection |
| Patient satisfaction (%) | 92.06 ± 4.33 | 91.80 ± 4.35 | - |
| Revision rate (%) | 3.50 ± 5.03 | 4.02 ± 5.37 | Revision due to complications |
| Neurological deficits and hematoma |
| Metric | Anterior approach | Posterior approach |
|---|---|---|
| Primary Indications | Cervical disc herniation, ventral spinal cord compression; radiculopathy due to central pathology | Foraminal stenosis, dorsal nerve root compression; radiculopathy caused by lateral or foraminal stenosis |
| Techniques | Anterior cervical discectomy and fusion (ACDF), anterior cervical foraminotomy, cervical disc replacement | Posterior cervical foraminotomy, laminoplasty, posterior decompression and fusion |
| Functional recovery | NDI improvement > 70% in most studies; quicker resolution of radicular pain; JOA scores consistently improved | Functional recovery > 90%; “Good” or “Excellent” outcomes per MacNab criteria in most patients |
| Complications | Dysphagia (5%–10%, transient, resolving within weeks); minor risks of adjacent segment degeneration (1%–5%) | Dura tears (3%–6%); transient neurological deficits (e.g., thumb weakness in 3%–5% of cases) |
| Revision rates | Low, ranging from 1%–5%; most revisions for recurrent disc herniation or adjacent segment pathology | Slightly higher at 4%–6%; most revisions due to incomplete decompression or symptom recurrence |
| Operating time | Average 70–90 minutes for single-level procedures; multilevel ACDF may require up to 120 minutes | Shorter duration of 50–80 minutes for single-level surgeries; faster for isolated foraminal stenosis |
| Intraoperative blood loss | Minimal (< 20 mL), rarely exceeding 50 mL even in multilevel procedures | Negligible (< 10 mL); endoscopic techniques minimize blood loss further |
| Hospital stay | 1–2 Days; overnight observation for most cases | 1–3 Days; outpatient surgery possible for simpler procedures |
| Patient satisfaction | High (> 90%) | Slightly higher (> 92%) |
| Neurological recovery | > 95% improvement in radiculopathy or myelopathy; sensory deficits resolved in most cases | Comparable neurological recovery (> 90%); transient motor weakness observed in some patients |
| Complication-specific risks | Dysphagia: 5%–10% (transient); rare risk of adjacent segment degeneration (ACDF) | Dura tears: 3%–6%; transient nerve root irritation, e.g., C7 nerve root causing thumb weakness |
| Unique benefits | Direct access to ventral pathology; high effectiveness for central cord decompression | Avoids anterior tissue dissection; better access for dorsal stenosis and foraminal compression |
| Limitations | Dysphagia risk due to retraction of esophagus and trachea; longer recovery for multilevel fusion | Higher revision rates due to incomplete decompression; slightly increased transient neurological risks |
NM, not mentioned; AFECD, anterior full endoscopic cervical discectomy; PFECD, Posterior Full Endoscopic Cervical Discectomy; FPCF, full percutaneous cervical foraminotomy; ACDF, anterior cervical discectomy and fusion; PECD, posterior endoscopic cervical discectomy; T-EMG, triggered electromyography; CSM, cervical spondylotic myelopathy; CSA, cervical spondylotic amyotrophy; IOM, intraoperative monitoring; PE, percutaneous endoscopic; BE, biportal endoscopic; VBD, ventral bony decompression; SDD, simple dorsal decompression; CSR, cervical spondylotic radiculopathy; MD, microdiscectomy, EAD, endoscope-assisted discectomy.
NM, not mentioned; AFECD, anterior full endoscopic cervical discectomy; PFECD, Posterior Full Endoscopic Cervical Discectomy; FPCF, full percutaneous cervical foraminotomy; ACDF, anterior cervical discectomy and fusion; PECD, posterior endoscopic cervical discectomy; T-EMG, triggered electromyography; IOM, intraoperative monitoring; PE, percutaneous endoscopic; BE, biportal endoscopic; VBD, ventral bony decompression; SDD, simple dorsal decompression; VAS, visual analogue scale; JOA, Japanese Orthopaedic Association; mJOA, modified JOA; FEPCF, Full-endoscopic posterior cervical foraminotomy; MD, microdiscectomy, EAD, endoscope-assisted discectomy; OPCF, open posterior cervical foraminotomy; PECF, percutaneous endoscopic cervical foraminotomy; CDR, cervical disc replacement.
Values are presented as mean±standard deviation.
NDI, Neck Disability Index; JOA, Japanese Orthopaedic Association.