Abstract
-
Objective
Full endoscopic cervical surgery (FECS) is an evolving minimally invasive approach for treating cervical spine disorders. This systematic review synthesizes current evidence on the clinical outcomes and patient perspectives associated with FECS, specifically evaluating its safety, efficacy, and overall patient satisfaction.
-
Methods
A systematic search of the PubMed/MEDLINE, Cochrane Library, Embase, and Web of Science databases was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies published between January 2000 and September 2024 that reported on clinical outcomes or patient perspectives related to FECS were included. Risk of bias was assessed using the ROBINS-I (Risk Of Bias In Non-randomized Studies - of Interventions) tool and the Cochrane Risk of Bias tool. Inclusion criteria encompassed randomized controlled trials, prospective cohort studies, retrospective studies, and observational studies focused on adult populations undergoing FECS for cervical spine surgery.
-
Results
The final synthesis included 30 studies. FECS was associated with significant reductions in both cervical and radicular pain, as well as meaningful functional improvements, measured by standardized clinical scales such as the Neck Disability Index and visual analogue scale. Patient satisfaction rates were consistently high, with most studies reporting satisfaction exceeding 85%. Complication rates were low, primarily involving transient neurological deficits that were typically resolved without the need for further intervention. Nonrandomized studies generally presented a moderate risk of bias due to confounding and selection, whereas randomized controlled trials exhibited a low risk of bias.
-
Conclusion
FECS is a safe and effective minimally invasive surgical option for cervical spine disorders associated with substantial pain relief, functional improvement and high levels of patient satisfaction.
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Keywords: Full endoscopic cervical surgery, Minimally invasive spine surgery, Cervical disc herniation, Clinical outcomes, Patient satisfaction
INTRODUCTION
Cervical spine disorders, including cervical disc herniation, spondylosis, and stenosis, are prevalent conditions that significantly contribute to pain, functional impairment, and disability worldwide. Epidemiological data indicate that cervical spondylosis affects approximately 10%–20% of the global population, with prevalence increasing with age, particularly among individuals over 50 years. These conditions impose a substantial socioeconomic burden, leading to increased healthcare costs and loss of productivity [
1-
3]. Clinically, patients with cervical spine disorders often present with a range of symptoms. Cervical disc herniation and spondylosis frequently cause radicular pain, characterized by sharp, shooting discomfort radiating down the arm due to nerve root compression. Neurological manifestations may include motor weakness, sensory deficits, and diminished reflexes in the affected limbs. In cases of severe cervical stenosis, myelopathy can develop, presenting signs such as gait disturbances, hand clumsiness, and loss of fine motor skills, which can significantly impair daily activities [
1-
3]. These conditions often lead to radicular or myelopathic symptoms that profoundly impact a patient’s quality of life and necessitate surgical intervention when conservative treatments fail. Traditional open cervical spine surgeries, such as anterior cervical discectomy and fusion (ACDF), have long been considered the gold standard for addressing these conditions [
2,
3]. While effective, these approaches are associated with several drawbacks, including extensive soft tissue dissection, prolonged recovery times, postoperative pain, and the potential for long-term complications such as adjacent segment disease (ASD).
In recent years, advancements in minimally invasive techniques have made full endoscopic cervical surgery (FECS) a promising alternative to traditional spine surgery [
4,
5]. FECS uses a high-definition endoscope and specialized instruments through small incisions, offering benefits like reduced tissue trauma, shorter hospital stays, faster recovery, and fewer complications. FECS can be performed using anterior or posterior approaches [
4,
5]. The anterior approach is typically used for discectomy, fusion, and foraminotomy, while the posterior approach is employed for decompression, laminectomy, and fusion. These procedures, including decompression, discectomy, foraminotomy, and laminectomy, aim to relieve nerve root or spinal cord compression and, when combined with fusion, stabilize the spine. FECS offers effective treatment with minimal disruption to surrounding tissues, often yielding outcomes comparable to traditional open surgeries [
5,
6].
Despite the growing popularity of FECS, the available evidence remains fragmented, primarily consisting of small cohort studies and retrospective analyses, which limits the broader applicability of their findings. Moreover, patient-reported outcomes, including not only satisfaction but also factors such as return to work, activity levels, and overall functional recovery, are becoming increasingly critical in evaluating the true impact of surgical interventions on quality of life. These gaps in the existing literature underscore the importance of conducting a comprehensive systematic review that integrates both clinical outcomes and patient perspectives, offering a more complete understanding of FECS’s efficacy and its effect on patients’ daily lives. The primary aim of this review was to clarify the safety and efficacy of FECS in pain relief, functional improvement, and complication rates. A secondary aim is to examine patient-reported outcomes, including satisfaction, return to work, and quality of life, to provide a holistic understanding of the procedure’s impact on patients. By synthesizing the current evidence, this review seeks to inform clinical practice and highlight areas for future research in this evolving field.
MATERIALS AND METHODS
1. Search Methodology
A systematic review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (
Fig. 1) [
7]. The following databases were searched: PubMed/MEDLINE, Cochrane Library, Embase, and Web of Science. The search was restricted to articles published between January 2000 and September 2024. Search terms used included a combination of MeSH terms and keywords, such as “full endoscopic cervical surgery,” “cervical discectomy,” “clinical outcomes,” “patient satisfaction,” and “minimally invasive surgery.” Boolean operators (AND, OR) were used to refine the search results and ensure comprehensive coverage. Additionally, the reference lists of relevant articles were manually screened to identify additional studies that were not captured by the database search.
The study selection process was carried out independently by 2 authors. Initially, titles and abstracts of all identified studies were screened to exclude irrelevant articles. Full-text versions of potentially eligible studies were then retrieved and assessed in detail against the inclusion and exclusion criteria. In case discrepancies arose between the 2 reviewers regarding study eligibility, consensus was reached through discussion. If disagreements persisted, a third reviewer was consulted to resolve any remaining disputes.
3. Inclusion and Exclusion Criteria
The inclusion criteria for the study design were controlled trials (randomized controlled trials, RCTs), prospective cohort studies, retrospective studies, and case series involving adult patients (age≥ 18 years) who underwent FECS. The studies had to report clinical outcomes following FECS. These outcomes included pain relief, functional improvement, complication rates, revision rates, patient satisfaction, quality of life, and return to work. The exclusion criteria comprised single case report, narrative reviews, meta-analyses, conference abstracts, and technical notes. Studies focusing on other types of cervical spine operation, pediatric populations, or conditions involving the thoracic and lumbar spine were excluded. Additionally, articles not published in English were excluded.
4. Data Extraction
Two independent reviewers screened the titles and abstracts of identified studies. Full-text articles of potentially eligible studies were retrieved and reviewed in detail. Any discrepancies between the reviewers were resolved by consensus or by consulting a third reviewer. Data extraction was performed using a standardized form to ensure consistency. The extracted data included the following: study characteristics, such as author, publication year, study design, sample size, and study location. Patient demographics, including age, sex, symptom duration, level of disc herniation, and history of previous conservative treatment. Clinical outcomes include pain relief score, visual analogue scale (VAS), functional outcomes, Neck Disability Index (NDI), Japanese Orthopaedic Association, complication and revision rates. Patient perspectives encompass patient satisfaction, quality of life, return to work, and other patient-reported outcomes. The data were carefully verified for accuracy and completeness, and potential variations in pain assessment methods across studies were acknowledged to ensure clarity and consistency in the comparisons.
5. Risk of Bias Assessment
The risk of bias for each included study was assessed by 2 independent reviewers using the appropriate tools based on the study design. For nonrandomized studies, the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) tool8 was used, assessing 7 domains: bias due to confounding, selection of participants, classification of interventions, deviations from intended interventions, missing data, measurement of outcomes, and selection of reported results. Bias due to confounding was noted as a potential issue because patients with more severe baseline characteristics were more likely to receive certain interventions, potentially skewing outcome comparisons. For RCTs, the Cochrane Risk of Bias 2 (RoB 2) tool [
9] was employed, which evaluates bias across domains such as the randomization process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of the reported result. Missing outcome data were flagged as a moderate risk because a significant number of patients were lost to follow-up, which could affect the robustness of the reported results. Each domain was rated as “low risk,” “moderate risk,” “serious risk,” or “critical risk.” The overall risk of bias for each study was determined by the highest level of risk identified in any domain. Studies with a “serious” or “critical” risk of bias were considered to have significant methodological limitations. A serious risk of bias was observed due to participant selection issues, where nonrandomized allocation led to potential baseline imbalances that may have influenced outcomes. Disagreements between the reviewers regarding the risk of bias assessments were resolved through discussion or arbitration by a third reviewer, ensuring a comprehensive evaluation process and minimizing subjective biases.
This study was conducted in accordance with the Declaration of Helsinki and with approval from the Ethics Committee and Institutional Review Board of University of Phayao (Institutional Review Board [IRB] approval, IRB Number: HREC-UP-HSST 1.1/007/68).
RESULTS
The PRISMA 2020 flow diagram outlines the process of a systematic review that screened studies related to full endoscopic cervical spine surgery. Initially, 1,772 records were identified from databases such as PubMed/MEDLINE, Cochrane Library, Embase, and Web of Science. After removing 1,243 duplicates and non-English articles, 529 records were screened. Of these, 389 were excluded based on their titles, and 100 reports were assessed for eligibility. Ultimately, 70 reports were excluded for not meeting criteria related to clinical relevance or specific surgical focus, leaving 30 studies included that pertained to full endoscopic cervical spine surgery, emphasizing clinical outcomes and patient perspectives. A total of 30 studies were included in this systematic review, comprising patients who underwent FECS for various cervical spine disorders. The studies were conducted between 2008 and 2024, with sample sizes ranging from 3 to 252 patients. The study designs included RCTs, prospective cohort studies, and retrospective observational studies. Details of the study populations, including age, symptom duration, and previous treatments, are summarized in
Table 1 [
5,
6,
10-
37].
1) Sample size
The study had a large sample size of 252 patients in Zheng et al. (2018) [
12]. This variation indicates that while some studies focus on small, specific patient groups, others provide insights from more generalized, larger populations.
2) Age and sex
The age of patients across studies typically ranges from young adults (around 20–30 years) to older adults (up to 80 years), with most studies focusing on middle-aged adults (40s–60s). Sex distribution varies slightly by study, with most male patients in some studies (especially in military or occupational groups). However, several studies have balanced gender ratios, with some specifically mentioning the percentage of females and males in the cohort.
3) Nationality
The studies predominantly focus on populations from Asian countries. China: Most of the studies are based in China, and they significantly represent Chinese patients. South Korea: Several studies were conducted in South Korea, highlighting a focus on East Asian populations. Japan: A few studies are based in Japan. Smaller studies are conducted in Italy, Turkey, and Indonesia.
4) Symptom duration
The duration of symptoms before surgery varies widely, from just a few weeks to several months (2–12 months). Some studies did not provide specific data on symptom duration but indicated that patients had failed conservative treatment for a significant amount of time before being considered for surgery (4–6 weeks).
5) Level of disc herniation
The most reported levels of cervical disc herniation across studies are C4–5, C5–6, and C6–7. These levels are frequently associated with cervical radiculopathy and myelopathy, which are the most common indications for FECS.
6) Previous conservative treatment
A significant number of studies report that patients underwent conservative treatments with physical therapy, medications, or rest for at least 4–6 weeks before deciding to undergo surgery. This failure of conservative treatment is a typical criterion for selecting patients for surgery in the studies reviewed.
7) Clinical presentation
The clinical presentations of the patients in these studies generally include radicular pain, myelopathy, and motor or sensory deficits. These symptoms are commonly associated with cervical disc herniation and are typically the primary indications for surgery.
2. Overall Clinical Outcomes and Surgical Parameters
Clinical outcomes which included pain relief, functional improvement, complication rates, and patient satisfaction, were consistently reported across the studies. Surgical parameters, such as operating time, intraoperative blood loss and hospital stay, were also documented. The findings are summarized in
Table 2 [
5,
6,
10-
37].
1) Functional improvement and pain relief
Significant reductions in arm and neck pain were reported in most studies. Ruetten et al. [
5] demonstrated an 87.4% reduction in arm pain, and Kim et al. [
6] observed a 90% improvement in 2 of 3 patients. Neck pain was also significantly reduced, with VAS scores decreasing from preoperative values of 7.89 to 1.11 postoperatively in the study by Ye et al. [
11]. This trend was consistent across other studies, with significant improvements reported within 1 week to 12 months postoperatively. Significant pain relief was consistently observed across the included studies. Yang et al. [
10] reported substantial reductions in disability scores for both the anterior full endoscopic cervical discectomy and posterior full endoscopic cervical discectomy groups. Shu et al. [
17] demonstrated a marked improvement in neck pain, with the VAS score decreasing from 5.8 preoperatively to 1.1 at 12 months. Similarly, Lee et al. [
14] found that 95% of their patients experienced improvements, emphasizing the efficacy of FECS in providing significant pain relief and alleviating symptoms.
2) Surgical parameters
The mean operating time varied across studies, depending on the complexity of the procedure. Ruetten et al. [
5] reported a mean operating time of 28 minutes for full endoscopic posterior cervical foraminotomy (FPCF) and 68 minutes for ACDF. Other studies reported operating times ranging from 42.3 minutes (Kotheeranurak et al. [
35]) to 169.3 minutes (Ran et al. [
26]), reflecting differences in surgical techniques and patient factors. Intraoperative blood loss was minimal, with several studies reporting negligible or no measurable blood loss, indicating the minimally invasive nature of FECS.
3) Hospital stay
The mean hospital stay was generally short, with most studies reporting stays between 1 and 4 days. For instance, Zheng et al. [
12] reported an average hospital stay of 1 day, while Wan et al. [
13] noted a mean stay of 3 days. This reflects the benefit of the minimally invasive approach, allowing patients to recover more quickly compared to traditional open surgeries.
1) Clinical outcome, surgical parameters, and complication of anterior approach
The anterior approach is primarily utilized for pathologies such as cervical disc herniation and ventral spinal cord compression. This approach commonly involves procedures like anterior cervical discectomy, foraminotomy, and fusion. The clinical outcomes were significant reductions in radicular pain reported across most studies, with pain relief exceeding 85% in several cohorts (Ruetten et al. [
5] and Zheng et al. [
12]). Functional improvements, measured by the VAS and NDI, demonstrated consistent preoperative-to-postoperative reductions. Zheng et al. [
12] reported a mean VAS reduction from 7.5 to 1.2. Complications included dysphagia was a reported complication, reported in 5%–10% of cases, typically transient and resolving within weeks. Ruetten et al. [
5] observed transient dysphagia in 3% of patients undergoing ACDF. Recurrence of symptoms was rare but noted in some long-term studies, with rates ranging from 1% to 5%. Surgical parameters were operating times varied widely, with a mean of 70–90 minutes for anterior procedures, depending on complexity and surgical technique. Blood loss was minimal, typically below 20 mL, reflecting the minimally invasive nature of these approaches.
2) Clinical outcome, surgical parameters, and complication of posterior approach
The posterior approach is preferred for dorsal pathologies, such as foraminal stenosis and radiculopathy, where nerve root decompression is the primary goal. Techniques include posterior cervical foraminotomy, laminoplasty, and fusion. Clinical outcomes included pain relief was substantial, with posterior approaches yielding a VAS improvement comparable to anterior procedures. Ye et al. [
11] reported a reduction in VAS scores from 7.8 preoperatively to 1.1 postoperatively. Functional recovery rates were high, with over 90% of patients achieving “good” or “excellent” outcomes as per MacNab criteria. The complications including dura tearing and transient neurological deficits were the most common complications. Shu et al. [
17] reported a 3% incidence of transient thumb weakness postoperatively. Revision surgery rates were slightly higher compared to anterior approaches, primarily due to incomplete decompression or recurrent symptoms (4%–6%). Surgical parameters were the average operating time for posterior procedures ranged from 50 to 80 minutes, with negligible intraoperative blood loss in most studies. Hospital stays were short, typically 1–3 days, demonstrating the efficiency of posterior endoscopic methods.
3) Comparative analysis between anterior and posterior approach
The anterior and posterior approaches demonstrated significant differences in complications and surgical outcomes included dysphagia was exclusively associated with the anterior approach, while dura tears and neurological deficits were more frequent with posterior methods. Patient satisfaction was consistently high for both approaches, exceeding 90% in most studies, with slightly higher satisfaction rates observed for posterior procedures due to lower dysphagia incidence. Pain relief was comparable across both approaches, with anterior procedures favored for ventral pathologies and posterior methods for dorsal pathologies. The importance of tailoring the surgical approach to the specific pathology and patient needs, ensuring optimal outcomes with minimal complications.
4. Overall Complication and Revision Rates
The risks associated with FECS involve considering the overall low complication rates but significant serious complications that can impact patient outcomes. Although the majority of complications are transient, such as radicular pain or sensory disturbances, and typically resolve without further intervention, there are still risks that need to be carefully managed. These include neurological deficits, such as temporary thumb weakness or dysesthesia, which, while generally mild, can be concerning for patients. Additionally, although uncommon, serious complications such as hematomas, dysphagia, or even permanent neurological deficits have been reported. The risk of revision surgery, primarily due to recurrent symptoms or incomplete decompression, ranges from 0% to 7.3%, with some studies, like that by Ruetten et al. [
5], indicating slightly higher rates for anterior approaches (4.7% for ACDF). Notably, the posterior approach group in the study of Xiao et al. [
16] had a lower revision rate (4.55%) compared to the anterior approach (10%).
Patient satisfaction was consistently high through studies, with rates exceeding 85% in most cases. Ruetten et al. [
5] reported that 96% of patients undergoing FPCF were satisfied with their outcomes, while Zheng et al. [
12] reported an 86.7% satisfaction rate. MacNab criteria were frequently used to assess patient satisfaction, with most studies reporting “excellent” or “good” outcomes. Overall clinical success, defined as the resolution of symptoms and improvement in function, was also favorable. Ye et al. [
11] reported a 100% clinical success rate in their cohort, and Zhong et al. [
31] reported 91.17% success rate based on patient-reported outcomes. The recurrence rate was minimal, with most studies reporting no recurrence of symptoms postoperatively.
Risk of bias was assessed using the ROBINS-I tool for nonrandomized studies (
Table 3 [
6-
10-
37],
Fig. 2) and the Cochrane RoB 2 tool for RCTs (
Table 4 [
5,
24],
Fig. 3). The 2 included RCTs by Ruetten et al. [
5] and Tacconi et al. [
24] were low risk across all domains, indicating strong methodological quality and reliable findings on the efficacy and safety of FECS. Nonrandomized studies generally exhibited a moderate to serious risk of bias, particularly in confounding and selection domains. Kim et al. [
6], Ye et al. [
11], and Wan et al. [
13] showed serious confounding risks due to potential uncontrolled variables affecting outcomes. Selection bias was also common, as many studies used retrospective designs or nonrandomized cohorts, leading to variability in patient characteristics and influencing reported outcomes. While nonrandomized studies like those by Lee et al. [
37] and Wang et al. [
23] had lower overall risk levels, most were impacted by moderate levels of bias due to participant selection and confounding. These findings underscore the need for additional high-quality RCTs with standardized protocols to validate the long-term efficacy and safety of FECS and reduce the impact of bias in future research.
DISCUSSION
The findings from this systematic review provide strong evidence supporting the clinical efficacy and patient satisfaction associated with FECS as a minimally invasive option for cervical spine pathologies. Across the studies analyzed, FECS consistently demonstrated significant reductions in cervical and radicular pain and improvements in functional outcomes, as evidenced by reductions in the VAS and improvements in NDI [
4,
6]. High patient satisfaction rates and low complication and revision rates further highlight the advantages of this approach compared to traditional open cervical surgeries [
10,
11,
38].
One of the key strengths observed in this review is the safety profile of FECS, which is particularly important in spine surgery, given the proximity of neural structures. The included studies reported low incidences of complications, with most adverse events such as transient neurological deficits or sensory disturbance being mild and resolving spontaneously [
12,
13]. This reinforces the minimally invasive nature of FECS, as it allows for decompression with minimal tissue disruption. Additionally, the short hospital stays and reduced postoperative disability rates reported across studies reflect the procedure’s ability to facilitate rapid recovery, enabling patients to resume daily activities and, in many cases, return to work more quickly than conventional surgical options [
14]. Patient-reported outcomes were a consistent focus across the reviewed studies, underscoring the increasing importance of these measures in evaluating surgical success. The high levels of satisfaction observed are likely attributable to the reduced postoperative pain, quicker recovery times, and minimal scarring associated with FECS. Furthermore, studies employing MacNab criteria often reported “excellent” or “good” outcomes, which speaks to the procedure’s ability to meet patient expectations and improve quality of life [
25]. These findings align with the broader literature on minimally invasive spine surgery, which emphasizes patient-centered outcomes as a critical component of clinical success [
17]. The analysis of clinical outcomes from all of the studies (
Table 2,
Fig. 4) reveals that endoscopic posterior surgical approaches generally result in lower complication rates, averaging 5.05%, compared to approximately 6.45% for anterior and combined anterior-posterior approaches. Additionally, patient satisfaction is higher with posterior methods, averaging 92.38%, while anterior and combined approaches show satisfaction 87.75%. These findings suggest that endoscopic posterior methods may provide better safety and patient-reported satisfaction. However, the choice between endoscopic approaches should be pathology, considering the patient’s condition and each surgical method’s potential benefits versus risks. Additionally, we performed a sensitivity analysis on the clinical outcomes of FECS studies. The analysis showed that pain relief is highly sensitive to extreme values, with the mean increasing significantly and the standard deviation decreasing once outliers were removed. Complication rate and patient satisfaction displayed minimal sensitivity to extreme values, indicating that these outcomes are generally stable across studies. The revision rate slightly increased the mean when outliers were excluded, suggesting some variability. Our sensitivity analysis is shown in
Table 5 and
Fig. 5 and authors compared the anterior and posterior approaches in
Table 6 and
Fig. 6 for cervical spine surgery based on all studies included in this systematic review.
Long-term surgical outcomes are essential to understanding procedures’ durability and sustained effectiveness. Studies of ACDF have shown that patients undergoing ACDF generally report sustained pain relief and improved quality of life over 5 to 10 years postsurgery. However, there is a noted risk of ASD, which can develop over time due to altered biomechanics [
39,
40]. Posterior cervical foraminotomy is known for maintaining good long-term outcomes with respect to pain relief and functional recovery, with low revision rates reported up to 10 years post-operation. It is often associated with fewer complications related to fusion compared to anterior approaches [
41-
43]. Recent studies of full endoscopic cervical discectomy indicate that patients experience continued pain relief and functional improvements for up to 3–5 years after surgery. The minimally invasive nature of this approach also correlates with reduced scar tissue formation and shorter recovery periods, contributing to long-term success [
4,
5,
44]. These cervical procedures underscore the importance of extended follow-up in evaluating the true effectiveness of cervical spine surgeries. Long-term follow-ups help to assess sustained benefits, potential complications, and the need for further intervention, providing comprehensive insights into the durability of surgical approaches.
The comparative choice between the anterior and posterior approaches in cervical spine surgery is primarily guided by the pathology’s location and the patient’s clinical presentation. The anterior approach is most suitable for addressing ventral pathologies such as cervical disc herniation and direct spinal cord compression. It is often preferred when radicular pain originates from nerve root compression due to a herniated disc or osteophyte formation at the intervertebral disc level. In contrast, the posterior approach is favored for dorsal pathologies, including foraminal stenosis, where nerve root decompression is the primary surgical objective. Conditions such as severe foraminal narrowing and lateral recess stenosis are best managed through posterior techniques, which allow targeted decompression while preserving spinal alignment. Benefits and surgical outcomes that both approaches demonstrate excellent outcomes in terms of pain relief, functional recovery, and patient satisfaction. Studies included in this review reported that anterior and posterior methods achieve comparable reductions in VAS scores for pain and improvements in functional metrics like the NDI [
5,
12]. Patient satisfaction exceeded 90% in both approaches, with slightly higher rates in posterior procedures due to fewer complications. These findings highlight the versatility and effectiveness of full endoscopic techniques in cervical spine surgery. Complications despite the shared benefits, the anterior and posterior approaches are associated with distinct complication profiles: The anterior approach showed dysphagia is the most notable complication, occurring in 5%–10% of cases, particularly in procedures involving extensive anterior soft tissue dissection. This complication is typically transient, resolving within a few weeks, and rarely requires intervention. The risk of recurrence or ASD, although minimal (1%–5%), is another consideration due to biomechanical alterations following anterior cervical fusion. Posterior approach: Dura tearing and transient neurological deficits, such as thumb weakness, are more common with posterior techniques. These complications occur in approximately 3%–6% of cases but are often self-limiting. Posterior procedures also carry a slightly higher revision rate (4%–6%), primarily due to incomplete decompression or recurrent symptoms.
Clinical decision-making based on the differences in indications, risks, and outcomes between the anterior and posterior approaches has significant implications for clinical decision-making. The selection of the surgical approach should be based on the following as pathology-specific considerations and compressive pathologies, the anterior approach provides direct access and effective decompression, minimizing the need for posterior manipulation. Conversely, posterior approaches are better suited for dorsal pathologies, offering precise decompression with minimal disruption to anterior structures. Patient factors: patient comorbidities, anatomical considerations, and functional demands should guide the decision. For instance, patients with swallowing disorders or a history of anterior neck surgery may benefit from a posterior approach. Based on the surgeon’s expertise that the surgeon’s familiarity with each technique plays a critical role in minimizing complications and optimizing outcomes. Procedural nuances, such as maintaining dura integrity in posterior approaches or minimizing soft tissue trauma in anterior methods, require technical precision. Impact of approach-specific risks understanding the distinct risks of each approach is essential for informed patient counselling. Patients undergoing anterior procedures should be advised about the potential for transient dysphagia, while those opting for posterior surgery should be aware of the risks of transient neurological deficits or revision surgery. These discussions ensure realistic expectations and reinforce the importance of tailored surgical strategies.
Despite these promising results, it is important to acknowledge the limitations within the current body of evidence. Most nonrandomized studies included in this review exhibited moderate to serious risks of bias, particularly in confounding and participant selection [
16]. These biases can affect the validity and generalizability of the results, as uncontrolled variables may have influenced outcomes independently of the FECS intervention. Although the 2 included RCTs demonstrated low risk of bias, the overall quality of evidence could benefit from additional high-quality RCTs with rigorous randomization protocols and standardized outcome measures [
18]. Heterogeneity among the studies regarding surgical techniques, outcome measures, and patient populations also posed a challenge to synthesis and comparison. For instance, varying operating times and using different endoscopic instruments reflect the evolving nature of FECS techniques and the individualized approach surgeons often adopt based on specific pathology and patient needs [
19]. While this variability highlights FECS’s adaptability, it also emphasizes the need for standardized protocols to allow for more consistent outcome reporting in future studies. Based on limitations, the authors initially considered conducting subgroup analyses or meta-regression. However, variations in how outcomes were reported and incomplete data across studies made these methods infeasible. For future studies, we recommend standardizing outcome measures and reporting formats. This would enable more rigorous analyses, such as subgroup analyses or meta-regression, and help in better understanding and managing the variability in study results.
The future of FECS is promising, particularly with the integration of emerging technologies. Specific advancements in robotic assistance and artificial intelligence (AI) hold significant potential to enhance further the precision, efficiency, and safety of FECS. For example, robotic systems can improve surgical precision by enabling more accurate navigation and positioning of instruments, thus reducing the likelihood of complications and improving overall patient outcomes [
45-
47]. AI applications can also play a key role in preoperative planning by analyzing patient data and predicting surgical outcomes, allowing for more personalized and optimized treatment strategies. During surgery, AI-powered systems can assist with real-time guidance, monitoring, and decision-making, ultimately reducing operative time and minimizing human error. Additionally, robotics can provide greater dexterity and stability during complex procedures, making it easier to navigate delicate spinal structures [
45-
47]. These technologies, alongside advancements in tissue engineering and regenerative therapies such as growth factors and stem cells, could complement FECS by promoting tissue healing and reducing the need for more invasive fusion procedures. Together, these innovations pave the way for significant advancements in FECS, improving surgical outcomes, reducing recovery times, and enhancing patient satisfaction [
21]. Finally, this review underscores the potential of FECS as a safe, effective, and patient-centered approach for the treatment of cervical spine disorders. The consistent improvements in pain relief, functional outcomes, and patient satisfaction highlight its advantages over traditional open procedures.
CONCLUSION
FECS offers significant clinical benefits, including effective pain relief, functional improvement, and high patient satisfaction, with minimal complications and low revision rates. While the current evidence is encouraging, further high-quality studies are needed to confirm this technique’s long-term efficacy and safety. The future of endoscopic spine surgery is poised for substantial advancements by integrating robotics, navigation and biological innovations, which will likely enhance the precision, safety, and scope of this minimally invasive approach.
NOTES
-
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.
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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.
Fig. 1.The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) diagrams in this systematic review.
Fig. 2.Risk of bias summary for nonrandomized controlled trials.
Fig. 3.Risk of bias for each randomized controlled trial.
Fig. 4.Summary all studies of pain relief, complication rate, patient satisfaction and revision rate.
Fig. 5.The sensitivity analysis visualization results for the 4 clinical metrics: pain relief, complication rate, patient satisfaction, and revision rate.
Fig. 6.Comparing the anterior approach and posterior approach across several key metrics, including pain relief, functional recovery, complication rates, revision rates, patient satisfaction, operating time, and hospital stay.
Table 1.Demographic and baseline characteristics of study populations
Table 1.
|
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 |
Table 2.Summary of clinical outcomes and surgical parameters
Table 2.
|
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 |
Table 3.Risk of bias analysis using ROBINS-I (Risk Of Bias In Non-randomized Studies - of Interventions) tool for nonrandomized controlled trial studies
Table 3.
|
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 |
Table 4.The randomized controlled trial risk of bias in this systematic review
Table 4.
|
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 |
Table 5.Summary of the sensitivity analysis and metric detail
Table 5.
|
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 |
Table 6.Comparison of anterior and posterior approaches
Table 6.
|
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 |
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, Sung Tan Cho2
