Lumbar disc herniation is a prevalent condition that significantly impacts patient quality of life, leading to chronic pain and disability [1]. The lifetime risk of lumbar disc herniation is about 30% and affects 1%–3% of the population annually, making it one of the most common causes of lower back pain [2,3]. Surgical intervention to remove a herniated disc to alleviate nerve compression has evolved from traditional open techniques to more minimally invasive microdiscectomies. Endoscopic discectomy presents an additional discectomy technique viewed as more minimally invasive than microdiscectomy promising shorter recovery times and reduced postoperative pain [4].

The adoption of endoscopic techniques reflects broader trends in spinal surgery towards minimizing invasiveness, a shift driven by advancements in technology allowing for similar outcomes with fewer perioperative complications [4]. Despite these advancements, comprehensive analyses of utilization and economic aspects, remain sparse. This gap is particularly notable given the changing dynamics of healthcare economics and the increasing scrutiny of procedure costs and reimbursement practices [5].

Endoscopic discectomy was assigned a Category I Current Procedural Terminology (CPT) code (62380) in 2017. Despite the distinct billing code designation, there is yet to be a consensus regarding the work relative value units assigned to this CPT code. A recent surge in clinical outcomes research in endoscopic discectomy surgery has emphasized the need for a nuanced understanding of the procedure's economic impact and its comparison with conventional surgical techniques [6].

Our study aims to provide a detailed comparative analysis of endoscopic discectomy and microdiscectomy, focusing on Medicare utilization and reimbursement from 2017 to 2021. To our knowledge, this is the first study that has examined billing and utilization of endoscopic discectomy surgery. This study will serve to assist with future formation of economic reimbursement models for lumbar disc herniation surgery.

The publicly available Medicare Part B National Summary Data files, containing comprehensive data on services billed to Medicare from 2000–2021, were utilized for this study [7]. Given Medicare's significant influence as the largest healthcare payer in the United States (US) and its role in shaping healthcare delivery and reimbursement policies amid an aging population, understanding its economic implications is crucial [5,8]. Services within these files are classified using CPT codes, with each code's data encompassing the total number of allowed services, allowed charges, and actual payments on an annual basis. The analysis specifically focused on the CPT codes for endoscopic discectomy (62380) and microdiscectomy (63030) from 2017 to 2021, considering the introduction of specific CPT code for endoscopic discectomy in 2017. For microdiscectomy, data from 2000-2016 was used to understand trends in microdiscectomy procedural volume and reimbursement per procedure prior to the introduction of the endoscopic discectomy CPT code. For each CPT code, the annual total allowed procedures, allowed charges, and actual payments were extracted from the dataset.

From 2017 to 2021, a total of 2,344 endoscopic discectomies and 126,501 microdiscectomies were performed under Medicare Part B. In terms of total reimbursement for the timeframe, endoscopic discectomy procedures received a total of $3,063,728.35 unadjusted for inflation, $3,250,430.84 in 2021 USD. For microdiscectomy, the total unadjusted reimbursement was $112,934,856.12, with the inflation-adjusted amount reaching $119,850,996.76.

This study presents a comprehensive analysis of the utilization and economic trends associated with endoscopic discectomy and microdiscectomy procedures under Medicare Part B from 2017 to 2021 since the assignment of a dedicated CPT code for endoscopic discectomy.

This study shows that endoscopic discectomy had an overall increase in operative volume of 8.58% from 2017 to 2021. A closer examination shows that endoscopic discectomy initially showed promising growth in 2018 and 2019. This may reflect an increased adoption of the endoscopic technique but can also represent wider awareness of the newly introduced CPT code. Endoscopic discectomy growth reversed in 2020. Given both techniques had a substantial decrease in procedural volume in 2020, the decrease is likely related in part to the disruption caused by the coronavirus disease 2019 pandemic. The 2021 data suggests that endoscopic discectomy has a persistent low utilization. The 2022 and 2023 data will have to be reviewed when available to fully confirm if the endoscopic volume will return to its pre-pandemic volume and growth curve.

Of the 2 techniques, microdiscectomy remains the more frequently utilized technique in the Medicare population. Microdiscectomy significantly declined by 5.56% per year during the study period. The decline is not explained by an adoption of endoscopic discectomy. This decrease follows the downward trajectory in utilization within the Medicare system that many neurosurgical procedures have experienced in recent years [10]. Our extended analysis into microdiscectomy data from 2000–2016 further suggests that the declining trend in procedural volume is a continuation of a long-standing pattern rather than an effect introduced by the availability of endoscopic discectomy.

The trend towards more frequent spinal fusions may be contributing to the decrease in microdiscectomy procedures. From 1998–2014, spinal fusions have experienced an 88% increase in utilization rate with a significant upward trend in the elderly subgroup [11]. A more recent analysis using Medicare Part B data demonstrated that the lumbar fusion utilization rate increased from 2012–2017, while microdiscectomy utilization declined [12]. The intersection of symptomatic degenerative spinal disease in an aging population with the advancements in minimally invasive fusion techniques may make fusion surgery a preferred treatment option [13,14].

When examining per procedure reimbursement, endoscopic discectomy received a substantially higher reimbursement than a microdiscectomy (Table 3). Though endoscopic reimbursement had been declining yearly during the study period, it remained higher than microdiscectomy reimbursement. The lack of substantial endoscopic volume growth despite higher reimbursement appropriately suggests that the higher reimbursement is not a critical driver of endoscopic discectomy adoption. The declining reimbursement may also represent attempts to more properly designate the commensurate reimbursement amount for a new technology. Endoscopic techniques remain a challenge to appropriately determine relative work and thus physician payment [15].

Microdiscectomy showed rising reimbursement in unadjusted dollars during the study period, but the adjusted data revealed it has just managed to keep up with inflation. These trends were also found after incorporating data from 2000–2016, suggesting that they are likely independent of endoscopic discectomy. The increase in reimbursement rate in 2009 can be largely attributed to the Medicare Improvements for Patients and Providers Act (MIPPA) of 2008. Specifically, MIPPA adjusted the Medicare Physician Fee Schedule by reversing a significant planned reduction of -10.6% and instead applying a slight increase of 0.5% [16]. This trend mirrors findings in Haglin et al. [5] which showed a significantly larger decrease in inflation-adjusted reimbursement across the 10 most common spinal and cranial procedures from 2000 to 2008 when compared to 2008 to 2018. Until this point, the decreasing annual reimbursement rate could be explained by the sustainable growth rate (SGR) under the Balanced Budget Act of 1997 [5]. Additionally, the large drop in microdiscectomy reimbursement in 2002 was likely due to a massive cut to Medicare reimbursement in a congressional effort to balance the federal budget that year [17]. In the years following the 2009 microdiscectomy reimbursement increase, congressional acts that delayed SGR-mandated cuts until its repeal by the Medicare Access and CHIP Reauthorization Act in 2015 appear to have contributed to the observed stabilization of reimbursement after adjusting for inflation [5]. The decline in microdiscectomy volume has to be investigated further but may be affected by the flat reimbursement when accounting for inflation.

Several recent studies have emphasized the clinical benefits of endoscopic discectomy. The improvement of functional outcomes like the Oswestry Disability Index and a shorter surgery duration in endoscopic discectomy compared to microdiscectomy support the potential superiority of endoscopic discectomy [18,19]. Other measures like a reduction of hospitalization time and complication rate support this trend [18,19]. Also, a recent randomized controlled noninferiority trial between the 2 procedures reported more favorable results for self-reported leg pain, back pain, functional status, quality of life, and recovery in those receiving endoscopic discectomy [20]. Despite these advantages and a growing body of evidence in the literature concerning clinical efficacy, the adoption of endoscopic discectomy within the Medicare population has been slow. This discrepancy may be attributed to several factors, including the initial costs associated with acquiring the necessary surgical equipment and the learning curve for surgeons transitioning to this newer technique [21].

This study, while comprehensive in its analysis of Medicare utilization and economic trends for endoscopic and microdiscectomy procedures, is not without limitations. The focus on Medicare Part B data does not capture the full spectrum of the spinal surgery reimbursement market. As the Medicare population tends to be an older population, it does not capture younger patients where non-fusion surgeries may be preferred.

Private insurance reimbursement data are not publicly available and were excluded. However, the policies of reimbursement rates and coverage used by the Centers for Medicare & Medicaid Services have been shown to guide private insurers and private reimbursement rates [22,23]. Another potential limitation of this investigation is the use of aggregate utilization and reimbursement from all geographical locations across the US. This restricts the possibility of identifying regional trends and variations in endoscopic discectomy and microdiscectomy. However, averaging the data allows for an overall analysis of national trends.

The available data does not allow us to examine other cost factors such as anesthesia and facility fees. Awake spine surgery, which can be considered as part of early recovery after surgery protocols, is an option for both techniques but endoscopic discectomy may be more adaptable to the awake protocol. Total cost with less anesthesia and facility setting may actually be lower with endoscopic discectomy despite the higher procedural reimbursement and relevant to a comprehensive payer such as Medicare [21,24].

The US landscape may not capture the broader picture within global spine surgery. This may be particularly relevant in regard to endoscopic techniques that may be more widely adopted in other countries.

This study examined changes in the procedural volume and reimbursement for endoscopic discectomy and microdiscectomy from 2017 to 2021. Endoscopic discectomy has not had a substantial adoption in the Medicare population and has had decreasing reimbursement despite potential clinical advantages. Microdiscectomy has had steady decline in procedural volume with reimbursement in line with inflation. Decreasing microdiscectomy volume is not explained by a rise in endoscopic techniques. This study will assist with future formation of economic reimbursement models for lumbar disc herniation surgery. Further work is needed to understand the trends to inform all stakeholders including surgeons, policy makers, healthcare administrators, and payors.