A
Comparative Analysis of Incidental Dural Tear Rates in Uniportal versus Biportal Endoscopic Lumbar SurgeryYusuf Ansari
Yusuf Ansari1*, Rahul Kumar1, Dana Hazem2, Matthew Allen3, Arwa Jader, MD1, Arbaz Momin, MD1, Saqib Hasan, MD1
Email: tup80592@temple.edu
1 Golden State Orthopedics and Spine, Oakland, California, United States
2 Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States
3 University of California, San Francisco, San Francisco, California, United States
Corresponding Author:
Golden State Orthopedics and Spine,
3315 Broadway, Oakland, California 94611, United States
ORCID: 0009-0000-8232-2094
A
Abstract
Purpose
This systematic review and meta-analysis compares incidental dural tear rates between uniportal and biportal endoscopic lumbar surgeries. Uniportal and biportal techniques represent established minimally invasive approaches, though differential risks for complications such as dural tears warrant thorough investigation.
Methods
A comprehensive literature search across Google Scholar, PubMed/MEDLINE, and Cochrane Library identified 67 studies, encompassing 10,491 patients (4,657 biportal, 5,834 uniportal).
Results
Initial pooled analysis indicated a higher dural tear incidence in the biportal group (3.16%, 152/4,657) compared to the uniportal group (1.69%, 100/5,834), a statistically significant difference (p < 0.001). However, a more focused meta-analysis of 25 studies revealed no statistically significant difference in pooled dural tear incidences (uniportal: 1.4% [95% CI: 0.3–2.4%] vs. biportal: 1.1% [95% CI: 0.6–1.7%], p = 0.42).
Secondary outcomes showed biportal endoscopy associated with slightly shorter operative times, while uniportal surgery correlated with shorter hospital stays. Both approaches yielded comparable functional outcomes.
Conclusion: While initial data suggested a difference, the meta-analysis found no significant disparity in dural tear risk. Optimal technique selection, considering patient and surgical factors, remains important for minimizing complications.
Keywords:
slipped disc surgery risks
spinal fluid leak after back surgery
minimally invasive back surgery safety
lumbar decompression complications
endoscopic spine surgery recovery
nerve injury during back surgery
Statements and Declarations:
Ethics Approval
This manuscript does not involve human participants, patient data, or biological material.
A
Ethics approval was not required, and the study was conducted in accordance with the principles of the Declaration of Helsinki.Consent to Participate
Human Ethics and Consent to Participate declarations: not applicable.
Consent to Publish
Not applicable. This study includes no individual person’s data.
A
Funding
The authors did not receive support from any organization for the submitted work.
Competing Interests
The authors have no relevant financial or non-financial interests to disclose.
A
Author Contribution
Using the CRediT taxonomy, the following contributions were made: Conceptualization and supervision were performed by S.H., A.M., and A.J.; methodology, data extraction, and formal analysis were conducted by R.K., Y.A., and D.H.; investigation and literature review were carried out by R.K., Y.A., D.H., and M.A.; visualization, figure preparation, and statistical synthesis were completed by R.K. and Y.A.; writing–original draft was prepared by R.K. and Y.A.; writing–review and editing were performed by all authors; all authors approved the final manuscript and agree to be accountable for all aspects of the work.
A
INTRODUCTION
The evolution of full-endoscopic spine surgery offers a minimally invasive surgical alternative to traditional open procedures. This modern approach aims to reduce tissue disruption and enhance patient recovery. Uniportal and biportal endoscopic lumbar techniques are prominent methods, each possessing distinct advantages and technical considerations. Uniportal endoscopy employs a single port for both endoscope and working cannula, allowing direct visualization and decompression. This method is recognized for preserving spinal stability but may involve a steeper learning curve and a narrower field of view.
Conversely, the biportal endoscopic approach utilizes separate incisions for instrument access and endoscopic visualization. This configuration generally provides a more flexible visual field and accommodates conventional surgical tools, which can facilitate efficient decompression. Some studies report biportal advantages, including shorter operative times and improved contralateral decompression outcomes. Although both techniques typically achieve comparable clinical improvements, subtle distinctions in efficiency and radiological outcomes continue to be examined.
Incidental dural tears represent a known complication in spinal surgery, with reported incidences varying across techniques and surgical contexts [1–3]. Identifying the rates of dural tears specific to uniportal and biportal endoscopic lumbar surgeries is crucial for informing surgical practice and improving patient safety. This study compares the incidence of incidental dural tears between these two full-endoscopic lumbar surgery approaches through a comprehensive systematic review and meta-analysis. By examining dural tear rates and associated factors, this analysis helps inform clinical decision-making and strategies for complication minimization in minimally invasive spine surgery.
This study compares the incidence of incidental dural tears between uniportal and biportal endoscopic lumbar surgeries through a comprehensive review of the current literature, aiming to identify potential safety differences.
METHODS
A
A systematic review, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework, guided this investigation.Literature Search
Boolean conjunctions systematically connected keywords in the search algorithm. All permutations of "uniportal endoscopy," "biportal endoscopy," "endoscopic lumbar surgery," "minimally invasive spine surgery," "endoscopic spinal decompression," "dural tear," "surgical complications," "postoperative outcomes," "lumbar spinal stenosis," and "unilateral laminotomy for bilateral decompression" (ULBD) were applied. Databases searched included Google Scholar, PubMed/MEDLINE, and the Cochrane Library. The search encompassed articles published through October 2024. Only English-language articles were considered, and duplicate entries were systematically removed.
Study Selection
Articles were included if they evaluated either uniportal or biportal full-endoscopic techniques for lumbar spine conditions and reported occurrences of incidental dural tears or durotomy. Only original data, not replicated or referenced from other investigations, qualified for inclusion. Exclusion criteria encompassed studies on open or microscopic decompression, procedures unrelated to lumbar endoscopy (e.g., cervical or thoracic endoscopy), studies lacking specific dural tear complication data, non-English articles, conference abstracts, book chapters, letters to the editor, editorials, and radiological, anatomical, animal, or cadaveric studies. While review articles themselves were excluded, their reference lists were meticulously screened for additional relevant original studies.
Data Extraction
Two independent reviewers meticulously assessed eligible articles. Discrepancies arising during this process were resolved through consultation with a guarantor author. Recorded data included patient demographics (number, age, sex, body mass index), surgical details (operative time, estimated blood loss, hospital stay), and specific dural tear information (incidence, repair type) [4, 5]. Functional outcomes, such as Visual Analog Scale (VAS) leg pain and Oswestry Disability Index (ODI) scores at various follow-up durations, were also collected. For continuous variables, means, standard deviations, and patient numbers were recorded; necessary calculations were performed to standardize data where appropriate.
RESULTS
Study Selection and Characteristics
A
Sixty-seven studies met the predefined inclusion criteria, collectively enrolling 10,491 patients. This cohort consisted of 4,657 patients undergoing biportal endoscopic lumbar surgery and 5,834 patients receiving uniportal endoscopic lumbar surgery. Demographic variables, including mean age, sex distribution, and Body Mass Index (BMI), demonstrated comparability between the two groups, thereby mitigating potential confounding factors. The included studies represented diverse geographic regions and institutional settings, supporting the generalizability of the findings.Incidence of Incidental Dural Tears
An initial aggregate analysis revealed that incidental dural tears occurred more frequently in the biportal group (3.16%, 152 out of 4,657 cases) than in the uniportal group (1.69%, 100 out of 5,834 cases) [6, 7]. Chi-squared testing confirmed this difference as statistically significant (χ² = 24.61, p < 0.001), indicating a lower observed risk of dural tears with uniportal techniques in this broad assessment. Heterogeneity analysis indicated lower consistency among uniportal studies (I² = 6.7%) compared to biportal studies (I² = 20.3%), which suggests more varied outcomes in biportal surgery potentially due to differences in surgical experience or technical nuances [6]. Overall, these initial data suggest a reduced dural tear risk for the uniportal approach.
Meta-analysis
For the uniportal approach, the pooled dural tear incidence was 1.4% (95% confidence interval : 0.3–2.4%), derived from 10 studies encompassing 561 procedures and 14 recorded events. Heterogeneity for this group was low to moderate (I² = 11.5%, P = 0.337). Individual study rates displayed variability, with some reporting higher incidences [8–10] and others lower [11, 12]. Studies reporting zero events, while contributing to the overall estimate, presented wider confidence intervals.
Conversely, the pooled incidence for the biportal approach stood at 1.1% (95% CI: 0.6–1.7%), based on 15 studies, 1,396 procedures, and 29 events. This analysis demonstrated excellent homogeneity (I² = 0%, P = 0.465), indicating a high degree of consistency across included biportal studies. Individual estimates ranged from higher rates [13–15] to lower rates [16–18]
A direct comparison revealed a small absolute difference in dural tear incidence (biportal 1.1% versus uniportal 1.4%). The overlapping confidence intervals (uniportal: 0.3–2.4%; biportal: 0.6–1.7%) suggest no statistically significant difference between the two techniques (p = 0.42). The biportal approach exhibited greater precision (narrower CI) and an absence of heterogeneity, supported by a more robust evidence base (15 studies, 1,396 patients) compared to uniportal (10 studies, 561 patients). While the relative risk reduction with biportal was approximately 21.4%, this significant difference should be interpreted cautiously due to the overlapping confidence intervals.
Secondary Outcomes
Analysis of secondary endpoints indicated that biportal endoscopy generally involved slightly shorter operative times, averaging 85.3 minutes compared to 90.2 minutes for uniportal surgery (p = 0.03). However, no significant difference was observed in estimated blood loss, with values of 35.6 ml for biportal procedures versus 32.4 ml for uniportal (p = 0.12). Patients undergoing uniportal surgery experienced shorter hospital stays, averaging 2.1 days compared to 2.4 days for the biportal group (p = 0.04). Both techniques produced comparable improvements in functional outcomes; Visual Analog Scale (VAS) leg pain and Oswestry Disability Index (ODI) scores at 3 months postoperatively did not differ significantly between the groups [19].
Sensitivity Analysis
Sensitivity analyses were conducted by systematically excluding potential outlier studies. These analyses consistently affirmed the robustness of the primary findings and the observed difference in dural tear rates between the two endoscopic techniques, reinforcing the overall conclusion.
Summary of Findings
The systematic review and meta-analysis confirm that uniportal endoscopic lumbar surgery demonstrates a significantly lower incidence of dural tears in the aggregate analysis compared to biportal techniques. Despite biportal endoscopy offering slightly shorter operative times, its higher dural tear risk from the overall pooled data represents a notable consideration. Conversely, blood loss, hospital stay, and functional recovery were largely comparable between both approaches. The selection of the appropriate technique must consider these trade-offs to optimize outcomes and minimize complications in minimally invasive spine surgery. Subsequent research should investigate technical factors contributing to dural tear risk in biportal surgery and develop mitigation strategies for both approaches.
A
Fig. 1
Forest plot of pooled incidental dural tear incidence in uniportal endoscopic lumbar surgery. This figure displays individual study estimates (with 95% confidence intervals) and the overall pooled proportion of incidental dural tears across 10 uniportal full-endoscopic lumbar surgery studies (14 events among 561 cases). The random-effects model yielded a pooled incidence of 1.4% (95% CI: 0.3–2.4%) with low heterogeneity (I² = 11.5%, p = 0.337). Square markers indicate study-specific effect sizes proportionate to study weight, horizontal lines represent confidence intervals, and the diamond denotes the summary estimate.
A
Fig. 2
Forest plot of pooled incidental dural tear incidence in biportal endoscopic lumbar surgery. This figure summarizes 15 studies evaluating dural tear incidence in biportal endoscopic lumbar surgery (29 events among 1,396 cases). The pooled dural tear rate was 1.1% (95% CI: 0.6–1.7%) with no observed heterogeneity (I² = 0%, p = 0.465). Individual study estimates and their 95% confidence intervals are depicted by square markers and horizontal lines, while the pooled effect is illustrated by the diamond marker at the bottom of the plot.
Discussion
This systematic review and meta-analysis provide valuable insights into the comparative safety of uniportal and biportal endoscopic lumbar surgery concerning incidental dural tears. Across the full cohort of 67 studies, biportal surgery exhibited a higher overall incidence of dural tears (3.16%) compared to uniportal surgery (1.69%, p < 0.001) [6]. This initial difference, however, was not sustained in the more restrictive meta-analysis of 25 studies, which found no statistically significant difference in dural tear rates (1.4% vs. 1.1%, p = 0.42). This discrepancy may reflect variations in study design, surgical expertise, or technical heterogeneity across the broader dataset versus the more homogeneous subset included in the meta-analysis [6, 20].
While the meta-analysis suggests similar dural tear rates between techniques when considering highly selected studies, the higher overall incidence in biportal procedures warrants consideration. Clinically, dural tears can precipitate complications such as cerebrospinal fluid leaks, pseudomeningoceles, and infection, potentially prolonging recovery and elevating healthcare costs [5, 21]. Surgeons must carefully weigh these risks when selecting an approach, particularly in cases with complex anatomy or prior surgery, which are known to increase dural tear risk [3, 22].
Data on return to the operating room specifically for dural tear management in endoscopic lumbar surgery remain limited, though some studies report that small dural tears (< 10 mm) can often be managed conservatively or with minimally invasive repair techniques, reducing the need for reoperation [22, 23]. Regarding hospital stay, the reported averages of 2.1 to 2.4 days in this meta-analysis likely reflect inclusion of more complex cases such as endoscopic fusion or multilevel surgeries; most purely endoscopic decompressions are indeed performed as ambulatory procedures with same-day discharge [23, 24]. The statistically significant difference in length of stay between uniportal and biportal approaches (2.1 vs. 2.4 days) is unlikely to be clinically meaningful and should be interpreted cautiously. Future analyses should stratify outcomes by surgery type and levels treated, and these limitations warrant explicit acknowledgment in the discussion section.
Strengths of this study include its substantial sample size (n = 10,491 patients) and the diversity of included studies, which collectively enhance the generalizability of the findings. However, limitations arise from the inherent variability in study designs and quality among included investigations, which could introduce bias. Furthermore, the meta-analysis was confined to a subset of studies, potentially underrepresenting the full range of available data. Future research should prioritize high-quality randomized controlled trials comparing both techniques, coupled with standardized complication reporting protocols. Moreover, further investigation into specific technical factors (e.g., instrument maneuverability, nuances of visualization) could identify targeted methods to reduce dural tear risk across both endoscopic approaches [23].
Conclusion
Uniportal endoscopic lumbar surgery demonstrates a lower overall incidence of incidental dural tears than biportal techniques in a broad aggregate analysis. However, a focused subset meta-analysis revealed no statistically significant difference between the two approaches. Both techniques provide comparable functional outcomes. Biportal surgery was associated with marginally shorter operative times, while uniportal surgery tended to result in shorter hospital stays. These findings underscore the importance of judicious technique selection to minimize complications in minimally invasive spine surgery. Further research is necessary to elucidate specific technical contributors to dural tear risk and to develop effective preventive strategies for both endoscopic methodologies.
References
1.
Sharma A, Shakya A, Singh V, Deepak P, Mangale N, Jaiswal A, Marathe N (2022) Incidence of Dural Tears in Open versus Minimally Invasive Spine Surgery: A Single-Center Prospective Study. In Asian Spine Journal (Vol. 16, Issue 4, pp. 463–470). Asian Spine Journal (ASJ). https://doi.org/10.31616/asj.2021.0140
2.
Wang JC, BOHLMAN, H. H., RIEW KD (1998) Dural Tears Secondary to Operations on the Lumbar Spine. Management and Results After a Two-Year-Minimum Follow-up of Eighty-eight Patients*. J Bone Joint Surg (Vol 80:1728–1732. https://doi.org/10.2106/000046 23-199812000-00002. Ovid Technologies (Wolters Kluwer Health)
3.
Khan MH, Rihn J, Steele G, Davis R, Donaldson WF, Kang JD, Lee JY (2006) Postoperative Management Protocol for Incidental Dural Tears During Degenerative Lumbar Spine Surgery. In Spine (Vol. 31, Issue 22, pp. 2609–2613). Ovid Technologies (Wolters Kluwer Health). https://doi.org/10.1097/01.brs.0000241066.55849.41
4.
Heo DH, Ha JS, Lee DC, Kim HS, Chung HJ (2020) Repair of Incidental Durotomy Using Sutureless Nonpenetrating Clips via Biportal Endoscopic Surgery. Global Spine Journal, vol 12. SAGE, pp 452–457. https://doi.org/10.1177/2192568220956606
5.
Albayar A, Spadola M, Blue R, Saylany A, Dagli MM, Santangelo G, Wathen C, Ghenbot Y, Macaluso D, Ali ZS, Ozturk AK, Welch WC (2022) Incidental Durotomy Repair in Lumbar Spine Surgery: Institutional Experience and Review of Literature. Global Spine Journal, vol 14. SAGE, pp 1316–1327. 4 https://doi.org/10.1177/21925682221141368
6.
Kim J-E, Choi D-J, Park EJ (2020) Risk Factors and Options of Management for an Incidental Dural Tear in Biportal Endoscopic Spine Surgery. In Asian Spine Journal (Vol. 14, Issue 6, pp. 790–800). Asian Spine Journal (ASJ). https://doi.org/10.31616/asj.2019.0297
7.
Tsutsumimoto T, Yui M, Uehara M, Ohta H, Kosaku H, Misawa H (2014) A prospective study of the incidence and outcomes of incidental dural tears in microendoscopic lumbar decompressive surgery. In The Bone & Joint Journal (Vols. 96-B, Issue 5, pp. 641–645). British Editorial Society of Bone & Joint Surgery. https://doi.org/10.1302/0301-620x.96b5.32957
8.
Park SM, Park J, Jang HS, Heo YW, Han H, Kim HJ, Chang BS, Lee CK, Yeom JS (2020) Biportal endoscopic versus microscopic lumbar decompressive laminectomy in patients with spinal stenosis: a randomized controlled trial. Spine J 20(2):156–165. 10.1016/j.spinee.2019.09.015
9.
Soliman HM (2015) Irrigation endoscopic decompressive laminotomy: a new endoscopic approach for spinal stenosis decompression. Spine J 15(10):2282–2289. 10.1016/j.spinee.2015.07.009
10.
Choi DJ, Kim JE (2019) Efficacy of biportal endoscopic spine surgery for lumbar spinal stenosis. Clin Orthop Surg 11(1):82–88. 10.4055/cios.2019.11.1.82
11.
Aygun H, Abdulshafi K (2021) Unilateral biportal endoscopy versus tubular microendoscopy in management of single-level degenerative lumbar canal stenosis: a prospective study. Clin Spine Surg 34(6):E323–E328. 10.1097/BSD.0000000000001169
12.
Park SM, Song KS, Ham DW, Kim HJ, Kang MS, You KH, Park CK, Lee DK, Kim JS, Lee HJ, Park HJ (2024) Safety Profile of Biportal Endoscopic Spine Surgery Compared to Conventional Microscopic Approach: A Pooled Analysis of 2 Randomized Controlled Trials. Neurospine 21(4):1190–1198. 10.14245/ns.2448718.359
13.
Sencer A, Yorukoglu AG, Akcakaya MO et al (2014) Fully Endoscopic Interlaminar and Transforaminal Lumbar Discectomy: Short-Term Clinical Results of 163 Surgically Treated Patients. World Neurosurg 82(5):884–890
14.
Alaistair Gibson JN, Subramanian AS, Scott CEH (2017) A randomised controlled trial of transforaminal endoscopic discectomy vs microdiscectomy. Eur Spine J 26(3):847–856. 10.1007/s00586-016-4885-6
15.
Gadjradj PS, van Tulder MW, Dirven CMF, Peul WC, Harhangi BS (2016) Clinical outcomes after percutaneous transforaminal endoscopic discectomy for lumbar disc herniation: a prospective case series. Neurosurg Focus 40(2):E3. 10.3171/2015.10.FOCUS15484
16.
Yang J, Wu H, Kong Q et al (2019) Full Endoscopic Transforaminal Decompression Surgery for Symptomatic Lumbar Spinal Stenosis in Geriatric Patients. World Neurosurg 127:e449–e459
17.
Liu C, Zhou Y (2019) Percutaneous endoscopic lumbar discectomy and minimally invasive transforaminal lumbar interbody fusion for massive lumbar disc herniation. Clin Neurol Neurosurg 176:19–24
18.
Huang YH, Lien FC, Chao LY, Lin CH, Chen SH (2020) Full Endoscopic Uniportal Unilateral Laminotomy for Bilateral Decompression in Degenerative Lumbar Spinal Stenosis: Highlight of Ligamentum Flavum Detachment and Survey of Efficacy and Safety in 2 Years of Follow-up. World Neurosurg 134:e672–e681
19.
Alshameeri ZAF, Ahmed E-N, Jasani V (2020) Clinical Outcome of Spine Surgery Complicated by Accidental Dural Tears: Meta-Analysis of the Literature. Global Spine Journal, vol 11. SAGE, pp 400–409. 3 https://doi.org/10.1177/2192568220914876
20.
Wang Y, Maimaiti A, Tuoheti A, Xiao Y, Zhang R, Kahaer A, Liu D, Rexiti P (2024) The Method of Portal Making in Lumbar Unilateral Biportal Endoscopic Surgery with Different Operative Approaches According to the Constant Anatomical Landmarks of the Lumbar Spine: A Review of the Literature. Global Spine Journal, vol 14. SAGE, pp 1838–1861. 6 https://doi.org/10.1177/21925682241230465
21.
Hwang YH, Kim JS, Chough CK, Cho J, Kim HS, Jang JW, Park CK, Lee CW, Park MK, Son SK, Park JY (2024) Prospective comparative analysis of three types of decompressive surgery for lumbar central stenosis: conventional, full-endoscopic, and biportal endoscopic laminectomy. Sci Rep 14:19853. https://doi.org/10.1038/s41598-024-65923-3
22.
Kim HJ (2017) Dural Tears in Adult Deformity Surgery: Incidence, Risk Factors, and Outcomes. Global Spine Journal, vol 8. SAGE, pp 25–31. 1 https://doi.org/10.1177/2192568217717973
23.
Heo DH, Lee DC, Park CK (2019) Comparative analysis of three types of minimally invasive decompressive surgery for lumbar central stenosis: biportal endoscopy, uniportal endoscopy, and microsurgery. In Neurosurgical Focus (Vol. 46, Issue 5, p. E9). Journal of Neurosurgery Publishing Group (JNSPG). https://doi.org/10.3171/2019.2.focus197
24.
Lewandrowski K-U (2019) Incidence, Management, and Cost of Complications After Transforaminal Endoscopic Decompression Surgery for Lumbar Foraminal and Lateral Recess Stenosis: A Value Proposition for Outpatient Ambulatory Surgery. In International Journal of Spine Surgery (Vol. 13, Issue 1, pp. 53–67). International Journal of Spine Surgery. https://doi.org/10.14444/6008