Comparison of endoscopic and non-endoscopic lumbar decompression outcomes using ACS-NSQIP database 2017–2022
Highlight box
Key findings
• After propensity score adjusting for significant demographic variables, endoscopic patients were found to have favorable clinical outcomes including lower rate of adverse outcomes and blood transfusions.
What is known and what is new?
• A recently published study in 2022, utilizing the American College of Surgeons’ National Surgical Quality Improvement Program comparing 175 endoscopic laminectomy cases to 38,322 open or minimally invasive (MIS) laminectomy cases between 2017 and 2020 reportedly found a difference in adverse events between the two approaches, but the difference was lost after propensity matching.
• With 2 years of additional data included in our study—including nearly double the number of endoscopic patients (336 endoscopic vs. 55,111 open/MIS cases) and thus statistical power—we found that following propensity score adjusting for the same variables from the previous study, endoscopic patients had significantly less total adverse outcomes and lower rate of blood transfusions.
What is the implication, and what should change now?
• Given the rising trend in endoscopic techniques, these findings demonstrate a favorable outcome following the endoscopic approach in one of the largest comparisons with open surgery up to date. This should be encouraging for surgeons looking to implement newer MIS techniques into their practice.
Introduction
Minimally invasive (MIS) approaches to spine surgery have emerged as an appealing choice for both patients and surgeons alike. Historically, open lumbar decompression has been the standard treatment for lumbar stenosis. In this procedure, the surgeon makes a suitable longitudinal incision, conducts dissection through subcutaneous fat and paraspinal muscles and fascia, and removes posterior elements that include the lamina, portions of the facets, and overlying ligamentum flavum to achieve adequate visualization and access to the nerve impinging structures. However, in spine surgery, striking a delicate balance is crucial: surgeons must carefully weigh the necessity of resecting native or hypertrophic anatomical structures to address the underlying pathology against the risk of excessive resection, which could lead to instability, scarring, and new or exacerbated symptoms. In pursuit of improved postoperative pain management, reduced trauma to surrounding tissues, and decreased intraoperative blood loss, spine surgeons are continuously exploring less invasive techniques. Endoscopic methods for lumbar decompression have gained popularity in the United States in recent years. However, these techniques have been honed over decades internationally, where they have undergone multiple generations of refinement and have been supported by extensive published data (1).
Not only has the growing adoption of endoscopic spine surgery been observed through the surgeon community but has also coincided with a rising familiarity by increasingly educated patients. In a cross-sectional survey study performed in 2023, about two-thirds of the prospective spine surgery patients preferred endoscopic spine surgery as compared to open laminectomy after reading a summary of evidence information. The most important factor in the open laminectomy group was outcomes of treatment while the most important factor in the endoscopic group was wound size (2). While endoscopic spine surgery is still part of a relatively new phase of practice, as more data becomes accessible from various institutions, it is fitting to gather and conduct comparative analyses using large and widescale standardized databases such as the American College of Surgeons’ National Surgical Quality Improvement Program (ACS-NSQIP).
The first look at the incoming data provided to the ACS-NSQIP database comparing outcomes of endoscopic and traditional open spine surgery was performed and published in 2022 by Page et al. The authors compared the data from 2017-2020, when the Current Procedural Terminology (CPT) code for endoscopic procedures was first created. They discovered a trend to shorter operative time, significantly lower total length of stay and total adverse events with endoscopic decompression (3). However, after controlling for significant baseline patient differences, the previously mentioned differences in clinical outcomes were lost.
With an additional 2 years of data and nearly double the number of endoscopic cases at the time of compiling this review, the aim of this study is to provide an updated review of patient characteristics and adverse outcomes among those undergoing endoscopic or other approaches of lumbar decompression using data from the ACS-NSQIP database. We present this article in accordance with the STROBE reporting checklist (available at https://jss.amegroups.com/article/view/10.21037/jss-24-163/rc).
Methods
This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. Utilizing the ACS-NSQIP database from 2017 to 2022, a retrospective review was performed comparing outcomes of endoscopic and non-endoscopic lumbar decompressions. The ACS-NSQIP collects data from patient medical charts across more than 700 participating hospitals both nationally and internationally. The ACS-NSQIP provides risk-adjusted data which allows more precise comparisons between groups and tracks patients for 30 days after their operation for incidence of post-operative complications (4).
Patients were filtered from the ACS-NSQIP data based on their CPT code. CPT code of 63030 represented open or tubular-based surgery and CPT code of 62380 reflected endoscopic surgery. CPT codes 63030 and 62380 both represented laminotomy/laminectomy, partial facetectomy, foraminotomy, and/or excision of a herniated intervertebral disc of one lumbar interspace for decompression of the nerve root(s) regardless of approach. Baseline characteristics between patients undergoing decompression via open/tubular or endoscopic were identified and compared as well as preoperative risk factors including modified Charlson Comorbidity Index (CCI) and American Society of Anesthesiologists (ASA) class (5,6). The primary 30-day endpoints included operative time, length of stay, adverse outcomes, 30-day readmission, and return to the operating room (OR). Adverse outcomes were further broken down into superficial infection, deep infection, organ/space infection, wound dehiscence, pneumonia, unplanned intubation, pulmonary embolism, ventilator use >48 hours, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke/cerebrovascular accident (CVA), cardiac arrest, myocardial infarction, blood transfusion, deep vein thrombosis (DVT), sepsis, and septic shock.
Statistical analysis
All statistical tests were performed using SPSS v25 (IBM Corp., Armonk, NY, USA). Patient and perioperative characteristics were compared between endoscopic and open groups using Chi-squared tests and independent sample t-tests, with level of significance set at P<0.05. Statistical analyses of primary outcomes were repeated following propensity score matching (PSM), which was utilized to control for baseline traits between groups including age, sex, race, BMI, ASA, and CCI.
Results
Pre-PSM
Utilizing the ACS-NSQIP database from 2017 to 2022 querying CPT codes 62380 for endoscopic and 63030 for open/tubular lumbar decompressions, we were able to obtain and compare a total of 55,447 patients. The non-endoscopic included 55,111 patients and the endoscopic group had 336. On initial analysis age, race, and ASA were significantly different between the groups. On average, the endoscopic group was significantly older at 43.95±39.48 years old vs. the open/MIS group at 39.48±27.00 years of age (P=0.003). Similarly, a significant difference was found in race, with 73.1% of non-endoscopic group classifying as white vs. 67.6% of the endoscopic group (P=0.03) and a significant difference in ASA class (P=0.04) (Table 1). Analysis of outcomes performed during the 30-day postoperative period showed a trend toward shorter average length of stay in endoscopic group (P=0.07). Furthermore, a significantly lower rate of total adverse outcomes 1.2% for endoscopic was observed compared to the non-endoscopic group (1.2% vs. 3.5%, P=0.02). No differences were observed in terms of readmissions or return to OR (Table 2).
Table 1
| Category | Open (n=55,111) | Endoscopic (n=336) | P value |
|---|---|---|---|
| Age (years) | 39.48±27.00 | 43.95±39.48 | 0.003* |
| BMI (kg/m2) | 30.02±7.65 | 29.27±8.07 | 0.08 |
| Male | 30,748 (55.8) | 195 (58.0) | 0.44 |
| White race | 40,281 (73.1) | 227 (67.6) | 0.03* |
| Home discharge | 53,241/55,001 (96.8) | 326/334 (97.6) | 0.53 |
| CCI | 0.76 | ||
| 0 | 3 (0.0) | 0 (0.0) | |
| 1 | 22,831 (41.4) | 143 (42.6) | |
| 2 | 10,807 (19.6) | 58 (17.3) | |
| 3+ | 21,470 (39.0) | 135 (40.2) | |
| ASA class | 0.04* | ||
| 1 | 5,224 (9.5) | 17 (5.1) | |
| 2 | 30,919 (56.1) | 185 (55.1) | |
| 3 | 18,063 (32.8) | 128 (38.1) | |
| 4 | 838 (1.5) | 5 (1.5) | |
| 5 | 6 (0.0) | 0 (0.0) |
Data are presented as mean ± SD, n (%), or n/total (%). *, P<0.05. ASA, American Society of Anesthesiologists; BMI, body mass index; CCI, Charlson Comorbidity Index; SD, standard deviation.
Table 2
| Category | Open (n=55,111) | Endoscopic (n=336) | P value |
|---|---|---|---|
| Operative time (min) | 91.96±52.21 | 94.57±46.26 | 0.36 |
| Length of stay (days) | 1.22±2.79 | 0.95±1.84 | 0.07 |
| Adverse outcomes | 1,906 (3.5) | 4 (1.2) | 0.02* |
| Superficial infection | 452 (0.8) | 0 (0.0) | 0.12 |
| Deep infection | 137 (0.2) | 0 (0.0) | >0.99 |
| Organ/space infection | 182 (0.3) | 1 (0.3) | >0.99 |
| Wound dehiscence | 107 (0.2) | 2 (0.6) | 0.14 |
| Pneumonia | 105 (0.2) | 0 (0.0) | >0.99 |
| Unplanned intubation | 45 (0.1) | 0 (0.0) | >0.99 |
| Pulmonary embolism | 119 (0.2) | 0 (0.0) | >0.99 |
| Ventilator >48 hours | 28 (0.1) | 0 (0.0) | >0.99 |
| Progressive renal insufficiency | 29 (0.1) | 0 (0.0) | >0.99 |
| Acute renal failure | 10 (0.0) | 0 (0.0) | >0.99 |
| Urinary tract infection | 313 (0.6) | 1 (0.3) | >0.99 |
| Stroke/CVA accident | 28 (0.1) | 0 (0.0) | >0.99 |
| Cardiac arrest | 23 (0.0) | 0 (0.0) | >0.99 |
| Myocardial infarction | 56 (0.1) | 0 (0.0) | >0.99 |
| Blood transfusion | 347 (0.6) | 1 (0.3) | >0.99 |
| DVT | 191 (0.3) | 0 (0.0) | 0.64 |
| Sepsis | 190 (0.3) | 0 (0.0) | 0.63 |
| Septic shock | 28 (0.1) | 0 (0.0) | >0.99 |
| 30-day readmission | 1,713 (3.1) | 8 (2.4) | 0.53 |
| Return to OR | 1,186 (2.2) | 4 (1.2) | 0.34 |
Data are presented as mean ± SD or n (%). *, P<0.05. CVA, cerebrovascular accident; DVT, deep vein thrombosis; OR, operating room; SD, standard deviation.
Post-PSM
After PSM adjusting was performed, 334 patients were compared from each group (Table 3). Postoperative adverse outcomes were still shown to be significantly lower in the endoscopic group (1.2% vs. 4.8%, P=0.01), particularly with significantly lower rate of blood transfusions (0.3% vs. 2.4%, P=0.04) (Table 4).
Table 3
| Category | Open/tubular (n=334) | Endoscopic (n=334) | P value |
|---|---|---|---|
| Age (years) | 38.08±25.04 | 39.48±27.04 | 0.49 |
| BMI (kg/m2) | 29.80±7.27 | 29.28±8.09 | 0.38 |
| Male | 195 (58.4) | 194 (58.1) | >0.99 |
| White race | 227 (68.0) | 226 (67.7) | >0.99 |
| Home discharge | 315/330 (95.5) | 324/332 (97.6) | 0.14 |
| CCI | |||
| 0 | – | – | |
| 1 | 135 (40.4) | 142 (42.5) | |
| 2 | 77 (23.1) | 58 (17.4) | |
| 3+ | 122 (36.5) | 134 (40.1) | 0.18 |
| ASA class | |||
| 1 | 28 (8.4) | 17 (5.1) | |
| 2 | 176 (52.7) | 185 (55.4) | |
| 3 | 121 (36.2) | 127 (38.0) | |
| 4 | 9 (2.7) | 5 (1.5) | |
| 5 | – | – | 0.24 |
Data are presented as mean ± SD, n (%), or n/total (%). ASA, American Society of Anesthesiologists; BMI, body mass index; CCI, Charlson Comorbidity Index; PSM, propensity score matching; SD, standard deviation.
Table 4
| Category | Open (n=334) | Endoscopic (n=334) | P value |
|---|---|---|---|
| Operative time (min) | 96.35±63.93 | 94.66±46.30 | 0.70 |
| Length of stay (days) | 1.16±2.14 | 0.95±1.84 | 0.18 |
| Adverse outcomes | 16 (4.8) | 4 (1.2) | 0.01* |
| Superficial infection | 0 (0.0) | 0 (0.0) | <0.001 |
| Deep infection | 0 (0.0) | 0 (0.0) | <0.001 |
| Organ/space infection | 1 (0.3) | 1 (0.3) | >0.99 |
| Wound dehiscence | 0 (0.0) | 2 (0.6) | 0.50 |
| Pneumonia | 0 (0.0) | 0 (0.0) | <0.001 |
| Unplanned intubation | 0 (0.0) | 0 (0.0) | <0.001 |
| Pulmonary embolism | 2 (0.6) | 0 (0.0) | 0.50 |
| Ventilator >48 hours | 0 (0.0) | 0 (0.0) | <0.001 |
| Progressive renal insufficiency | 0 (0.0) | 0 (0.0) | <0.001 |
| Acute renal failure | 10 (3.0) | 0 (0.0) | <0.001 |
| Urinary tract infection | 1 (0.3) | 1 (0.3) | >0.99 |
| Stroke/CVA accident | 1 (0.3) | 0 (0.0) | >0.99 |
| Cardiac arrest | 0 (0.0) | 0 (0.0) | <0.001 |
| Myocardial infarction | 1 (0.3) | 0 (0.0) | >0.99 |
| Blood transfusion | 8 (2.4) | 1 (0.3) | 0.04* |
| DVT | 4 (1.2) | 0 (0.0) | 0.12 |
| Sepsis | 0 (0.0) | 0 (0.0) | <0.001 |
| Septic shock | 0 (0.0) | 0 (0.0) | <0.001 |
| 30-day readmission | 11 (3.3) | 8 (2.4) | 0.64 |
| Return to OR | 7 (2.1) | 4 (1.2) | 0.55 |
Data are presented as mean ± SD or n (%). *, P<0.05. CVA, cerebrovascular accident; DVT, deep vein thrombosis; OR, operating room; PSM, propensity score matching; SD, standard deviation.
Discussion
Although endoscopic techniques for spine surgery have been practiced for decades and encompass various methods, the adoption of endoscopy for spine surgery in the United States is still in its nascent stage. As more surgeons undergo training in endoscopy, a substantial amount of data will become available for future studies focusing on outcomes, cost-effectiveness, and safety. NSQIP database began recording endoscopic lumbar decompression procedures using the CPT code 62380 in 2017 and up to 2020, only 175 endoscopic lumbar decompression surgeries were included in the registry. However, in the subsequent 2 years (2021 and 2022), 161 additional endoscopic cases were performed and added, nearly equal to the amount performed from the first 4 years. Over the next several years, the incidence of endoscopic spine surgery cases is expected to continue to climb.
There are numerous advantages associated with endoscopic lumbar decompression, including the ability to minimize disruption to surrounding tissues while still effectively accessing the disc space and achieving thorough decompression of neural elements. Endoscopic decompression is commonly performed in two different techniques: uniportal full-endoscopic, and biportal endoscopic. There are different advantages of performing either method. In uniportal full-endoscopic surgery, a single working channel is utilized. Both the light source and the working portal are placed through a single channel. The eye position is directed in front of the lesion and moves with the maneuvering of the working instruments. This is performed through a tissue preserving small keyhole. In contrast, biportal endoscopic surgery is a newer technique that utilizes two small incisions less than one centimeter each that allows for the surgeon to have one hand on the light source and the other hand on a surgical instrument. Both instruments can maneuver irrespectively which increases the angle and quality of vision (7). Endoscopy because of its narrow surgical corridors and advanced machinery has been shown in multiple studies to significantly reduce the amount of soft tissue trauma, thus resulting in reduced patients’ pain levels and shortened recovery time (8).
Like many aspects of spine surgery, there are multiple approaches to each case, each with its own strengths and weaknesses. Some limitations of endoscopic surgery have been shown to result in inadequate decompression, nerve damage, and prolonged operation time, which all have been shown to improve as the learning curve flattens. With time and experience, surgeons determine which approach yields the most consistent and favorable results. With improvements of equipment and surgical technology, the advantages of endoscopic spine surgery over the conventional open decompressive laminectomy are increasing and the surgical indications for an endoscopic approach are still expanding (9-15). Given the learning curve attached with proper utilization of the endoscopic instruments, should be regarded as another tool in the ever-expanding arsenal of surgical techniques following sufficient training and experience.
We recognize that there are several limitations in the current study that must be recognized for full transparency as to the clinical significance of our results. Firstly, one of the major limitations of this study is in the way the dataset is elucidated within the ACS-NSQIP database. We utilize the CPT code as our main way to differentiate between our endoscopic and non-endoscopic cohort groups but given the lack of customizable options provided in our initial data query from the NSQIP database, our study lacks relevant surgical details including if the procedure for each given patient was specifically indicated for laminectomy only, disc excision only or both, as well as the specific lumbar level operated on.
In particular, the CPT code of 63030 has a level of ambiguity given that the code includes surgeries that consist of either open or tubular retractor systems. Despite this, there is evidence in the literature that the open and tubular techniques have similar surgical differences to the endoscopic approach specifically as it concerns relative surgical invasiveness. A recent randomized controlled trial by Kotheeranurak et al. comparing full-endoscopic and tubular-based microscopic decompression in the setting of lumbar spinal stenosis showed that the full-endoscopic resulted in significantly reduced patient-reported back pain, shorter hospitalization, and less blood loss (16). In another design by Hwang et al., like what was observed by Kotheeranurak et al., the endoscopic laminectomy group compared to open was associated with improved back pain and reduced length of hospital stay, as well as greater muscle preservation as measured by relevant lab biomarkers (16,17). Therefore, as shown by these study examples, endoscopic procedures as performed under the different CPT code of 62380 can be effectively distinguished to both open and tubular approaches, thus validating the analyses performed in the present study.
It must also be said that while code 62380 is primarily used for endoscopic spinal procedures, there are still many surgeons who use 63030. This is primarily due to the fact that regardless of open or endoscopic approach many insurance companies do not recognize or approve the 62380 code. Unfortunately, because the dataset cannot be queried by terms such as variations of the word “endoscopy”, this also serves as another source of potential collection bias. Another limitation associated with our surgical case collection from a national registry was that we were unable to receive data on surgeon experience or skill level. These factors are likely contributable factors in the technique employed in decompression by experts or early adaptors of the approaches described in the study.
Conclusions
To summarize, in this study, endoscopic discectomy exhibited a notably reduced incidence of overall adverse events, and a significantly lower rate of blood transfusions compared to open or MIS discectomy. These findings, derived from the ACS-NSQIP data, align with the documented advantages of endoscopic techniques in existing literature. With the increasing adoption of endoscopic surgery across the United States, a wealth of additional data will emerge for future research endeavors.
Acknowledgments
None.
Footnote
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jss.amegroups.com/article/view/10.21037/jss-24-163/rc
Peer Review File: Available at https://jss.amegroups.com/article/view/10.21037/jss-24-163/prf
Funding: None.
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-163/coif). The authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
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