Lumbar disc herniation is a common pathology, having been attributed to nearly 20% of all patients with low back pain and cited as the most common cause of sciatica in adults [1-5]. While many patients respond to conservative management—including medications, physical therapy, and lifestyle modifications—some remain refractory and require surgical intervention. Open discectomy has traditionally been considered the gold standard for surgical treatment of lumbar disc herniation, but minimally invasive endoscopic discectomy techniques are increasingly being adopted [2,3].

Various endoscopic techniques—including microendoscopic discectomy (MED), percutaneous endoscopic discectomy, and full-endoscopic discectomy (FED)—have gained popularity due to their potential advantages in efficacy and safety [2-6]. These minimally invasive methods allow access to the lumbar disc while preserving surrounding bony structures and soft tissues. Several studies have suggested that endoscopic approaches may reduce operative time, intraoperative blood loss, and postoperative pain while improving overall patient satisfaction [7-10]. However, many of these studies are limited by small sample sizes and conflicting evidence [11-13].

Despite the growing utilization of endoscopic discectomy, there is a need for large-scale comparative analyses to better understand its potential advantages over open surgery. In this study, we conducted one of the largest retrospective cohort analyses to compare postoperative outcomes between endoscopic and open single-level lumbar discectomy.

From an initial population of 444,662 patients undergoing single-level lumbar discectomy, 243,684 patients met the inclusion criteria after applying the exclusion criteria. This cohort comprised 1,470 patients who underwent endoscopic discectomy and 242,214 who underwent open discectomy. Utilizing a 1:3 propensity score matching based on age, sex, CCI, and specific comorbidities, we obtained a well-balanced cohort of 5,640 patients, including 1,416 in the endoscopic group and 4,224 in the open surgery group (Figure 1). The unmatched patients (n=238,044) were excluded from further analysis. Baseline patient demographics and complication rates before matching are detailed in Supplementary Table 1.

Lumbar disc herniation is a common cause of low back pain, often necessitating surgical intervention when conservative management fails [1-5]. The operative surgical approach has been the standard of care for accessing the disc space for years. However, the advent of endoscopic spine surgery has prompted a shift towards minimally invasive techniques. The clinical appeal of these techniques is evident–minimizing the surgical incisional area may reduce inflammation and expedite recovery. Nevertheless, studies comparing open versus endoscopic lumbar discectomy have yielded inconsistent results and are often limited by small sample sizes [11-13]. Given the technical demands and resource allocation required for endoscopic surgery, it is crucial to understand the complication profiles associated with each approach. As such, our study aimed to elucidate the potential benefits of open versus endoscopic lumbar discectomy by analyzing procedure cost and 30-day postoperative outcomes using a large-scale national claims database.

Our findings indicate that, compared to the open discectomy cohort, patients who underwent endoscopic discectomy experienced significantly lower rates of SSI, overall surgical complications, and 30-day readmission. This consists of several prior studies that have reported reduced intraoperative blood loss, perioperative back pain, hospital length of stay, total complications, and patient satisfaction following endoscopic discectomy [2-8,14-16].

SSI after spinal surgery occurs in up to 12% of patients and is associated with significant morbidity and mortality [17]. Minimally invasive techniques inherently reduce the exposure of deep tissue to external contaminants, which may reduce the risk of infection. Our study echoed this, reporting a higher rate of SSI in the open discectomy group (OR, 2.69; 95% CI, 1.06–6.85). Similarly, multiple prior studies utilizing national databases in Japan found that patients treated with endoscopic discectomy experienced lower rates of SSI compared with patients treated with open discectomy [18,19]. This was further supported by an independent case-control study in 2014 reporting that patients undergoing open spinal surgery were 5.77 times more likely to develop SSI compared with patients undergoing spinal surgery with an endoscopic approach [20].

In our study, surgical complications such as nerve injury, hematoma, wounds, or cerebrospinal fluid leak were higher in the open surgical group (OR, 2.16; 95% CI, 1.11–4.17). This is consistent with a large systematic review and meta-analysis of 35 studies in the literature that found MED and FED to result in fewer wound complications than open micro-discectomy [21]. This may be attributed to more significant tissue disruption during open surgery, thus increasing the risk of subsequent injuries. Additionally, open surgery may be more likely to trigger the systemic cytokine response to injury, which has been previously associated with postoperative complications. The blunting of this response may play a role in the lower incidence of surgical complications in the endoscopically treated group [22,23].

Interestingly, the 2 groups had no statistically significant difference in the rate of UTI, pneumonia, acute kidney injury (AKI), deep vein thrombosis (DVT), hematoma, and need for blood transfusion. This finding was unexpected, as open discectomy had been previously associated with longer hospital course [14,16], as well as a higher rate of UTI, pneumonia, blood transfusion, AKI, MI, and DVT [24]. While these complications are notoriously difficult to compare due to their rarity, the large sample size in our study provides a more robust analysis, potentially challenging the prevailing view that endoscopic discectomy offers an advantage in reducing the rate of medical complications.

The open discectomy group had a higher readmission rate within the first 30 days postoperatively (OR, 3.09; 95% CI, 2.19–4.36). The observed readmission rate is likely associated with the higher rate of surgical complications and the need for their subsequent management. Interestingly, there was no significant difference in the rate of subsequent fusion surgeries within our study, suggesting neither method was superior in minimizing adjacent disc disease and preventing the need for subsequent fusion. While beyond the scope of this study, it is essential to highlight that several prior studies have reported a higher rate of disc herniation recurrence in endoscopic procedures compared to open ones [25-27].

Lastly, it is pivotal to acknowledge that endoscopic spinal surgery requires a unique skill set that differs from the traditional open approach. Surgeons must adapt to working within a limited visual field, often relying on indirect visualization and specialized instruments. The learning curve for endoscopic techniques may be challenging, and relatively inexperienced operators may encounter higher rates of intraoperative difficulties such as poor visualization, unintended nerve injury, or soft tissue damage [28-30]. The variability in complication rates reported in the literature may, in part, be attributed to differences in operator experience with the endoscopic technique.

This study identifies several advantages of endoscopic discectomy over open discectomy. The comparison between endoscopic and open discectomy techniques has been clouded by conflicting results in the literature, often driven by small sample sizes and suboptimal study design. By leveraging a large sample size and controlled matching, our study provides strong evidence supporting endoscopic discectomy's non-inferiority and potential superiority over open discectomy.

Nevertheless, the study inherited several limitations that must be considered when interpreting the results. Firstly, the classification of patient demographics and outcomes was based on ICD codes, susceptible to underreporting, coding errors, or inaccuracies. The variability in coding practices could potentially impact the accuracy and completeness of our findings. Additionally, the retrospective design of this study limits our ability to establish causal relationships between the type of the procedure and the outcomes observed. While we identified associations, unmeasured confounding factors may have influenced these relationships.

The prevalence of comorbidities such as hypertension, diabetes, and depression in our matched cohort was higher than expected compared to the general population. This reflects both the characteristics of surgical patients captured in national claims databases and the enrichment of comorbidity rates inherent to propensity score matching in order to achieve balance between cohorts. Additionally, although age was incorporated as a continuous matching variable, we did not perform subgroup analyses stratified by age groups (e.g., <50 years vs. ≥50 years), which could reveal important differences in physiological recovery and complication profiles.

Furthermore, although clinical benefit is best assessed through validated patient-reported outcomes (e.g., visual analogue scale, Oswestry Disability Index, or functional activity levels before and after surgery), such measures were not available in the MARINER database. These outcomes are particularly important in the context of minimally invasive surgery, where reduced tissue disruption may translate into faster recovery, earlier return to work, and improvements in quality of life. Unfortunately, claims-based data do not capture these functional or quality-of-life metrics, limiting our ability to directly quantify the lived benefit to patients. As such, we relied on postoperative complications and readmission rates as indirect indicators of surgical success. Similarly, operative duration is not reliability captured in claims databases and thus could not be analyzed. Surgeon-specific variables including experience level, case volume, and technical proficiency were also not available in this dataset, though these factors likely influence surgical outcomes and may partially explain variability in the literature.

While our follow-up period extended to 18 months, this timeframe may be insufficient to fully evaluate long-term outcomes, including the need for future spinal fusion or rates of recurrent disc herniation. Finally, our study does not separate specific endoscopic approaches, such as microendoscopic, percutaneous endoscopic transforaminal, percutaneous endoscopic interlaminar, and FED. While these distinctions could provide valuable insights, they were beyond the scope of this study. Future studies focusing on technique-specific comparisons, age-stratified outcomes, and prospective data collection with functional and quality-of-life measures are warranted to validate and expand on our findings.

In this large retrospective cohort study, endoscopic single-level lumbar discectomy was associated with fewer short-term complications compared to traditional open surgery for patients with symptomatic lumbar disc herniation. The endoscopic approach demonstrated reduced rates of SSIs, 30-day readmissions, and surgical complications—including nerve injury, hematoma, wound complications, and cerebrospinal fluid leak. These findings suggest that endoscopic discectomy may offer a lower-risk alternative to open surgery for appropriately selected patients. However, despite these promising results, further prospective research with longer follow-up is necessary to quantify better the risks associated with endoscopic techniques, particularly regarding long-term outcomes and rates of recurrent disc herniation. Such studies will help inform clinical decision-making and optimize patient care strategies.