Full-endoscopic dural repair using drain catheter: technical note

Abstract

Background

Repairing dural tears through a uniportal endoscopic approach presents significant technical challenges. This technical note describes a novel endoscopic suturing technique using standard instruments commonly available in most operating rooms.

Method

We describe the instrument preparation, operative steps, and a case illustration. The dural suturing technique is performed using standard endoscopic instruments with a custom-made knot pusher adapted from a No. 8 surgical drain catheter.

Conclusion

Our proposed surgical workflow and suturing technique enable effective endoscopic dural repair without the need for specialized equipment. It offers a practical solution that may reduce the need for conversion to open surgery.

Supplementary information

The online version contains supplementary material available at 10.1007/s00701-025-06613-5.

Relevant surgical anatomy

Dural tears are a common complication in lumbar surgery, with reported incidence rates ranging from 1.8% to 17.4%, occurring in both open and minimally invasive spine surgery (MIS) [8]. Dural tears often occur posteriorly but may also appear laterally or at the nerve root, where bony structures like the facet joint obstruct the visualization. Effective repair in these areas may require bone and soft tissue removal. Tear location significantly affects surgical access and treatment choice. In full-endoscopic spine surgery (FES), limited access and instrument constraints further complicate dural repair.

In uniportal endoscopic surgery, minimal iatrogenic dead space and preserved anatomical structures provide counterpressure, reducing the need for watertight closure. As a result, typical postoperative signs of dural tears, like CSF leakage or wound swelling, are uncommon [1]. Additionally, the limited bleeding induced by the endoscopy likely contributes to a natural sealing effect, similar to blood patching [4].

In FES, continuous water lavage obscures CSF leakage, making dural tears harder to detect. Irrigation pressure during the procedure also prevents rootlet extrusion, masking early signs of dural breach. Thus, a higher sense of suspicion is crucial, especially for small tears, and any observed dural disruption should be treated as a tear [10].

Description of the technique

Instrument preparation

We proposed a “FES Dural tear treatment kit”, consisting of common surgical tools available in most operating rooms. (Table 1).

Table 1.

FES Dural tear treatment kit

1	Dural collagen patch
2	Vascular suture Prolene 6–0 (non-cutting needle)
3	Drain no. 8
4	FES rongeur (as a needle holder)
5	FES scissors (as suture scissors)

One side of a Prolene no. 6–0 non-cutting vascular suture is reshaped to reduce its curvature to enable the needle to pass through the relatively narrow working channel. Surgical drain no. 8 serves as a knot pusher (Fig. 1, 2). The perforated tip is shortened to leave a single hole through which the suture end passes during knot tightening. (Fig. 3). The collagen dural patch is prepared by measuring the dural defect and cutting the patch slightly larger to ensure full coverage.

Fig. 1.

Drain catheter no.8 (left), A non-cutting needle Prolene 6–0 (right)

Fig. 2.

One side of the needle needs to be reshaped to reduce its curvature

Fig. 3.

Cut the tip of drain no.8, leaving one hole intact. Then, using the FES rongeur, measure the length to ensure the drain has adequate length through the endoscope

Suturing technique (video)

This case demonstration presents a 64-year-old female who sustained an intraoperative dural tear. Following the decompression procedure, the surrounding tissue was cleared to facilitate precise identification and access to the dural defect. Use the FES rongeur as a needle holder. During suturing, pass the needle through the dura over the defect, then retrieve the needle back through the working channel. Tie the knot outside the endoscope and use the modified drain to push the knot through the working channel towards the dura (Fig. 4). Under endoscopic visualization, observe the knot as it tightens. After suturing successfully, use FES scissors to cut the excess suture material. Finally, apply an onlay dural patch using the FES rongeur. Endoscopic dural repair technique is demonstrated (Fig. 5, Video 1). After a FES dural tear surgical treatment, immediate patient mobilization and standard postoperative rehabilitation are permitted.

Fig. 4.

Suturing technique using an FES rongeur as a needle holder (A, B). Utilizing a one-hole no.8 drain catheter as a knot pusher by passing one end of the suture through the distal hole (B–E)

Fig. 5.

Steps of dural suturing through uniportal endoscopic approach; A: Identify and clear surrounding tissues to access the dural defect; B: Suturing with a pre-shaped needle using FES rongeur as a needle holder; C: Knot tightening with a custom-made knot pusher; D: Cut excessive suture material with the FES scissors; E: Onlay collagen patching

Indications

Our recommended surgical workflow is specifically designed to manage intraoperative dural tears during uniportal endoscopic spine surgery. It adapts the “Papavero” systematic approach for FES surgery, incorporating the unique features of this technique and aligning with established recommendation algorithms [6, 9].

The perioperative detection of a tear and evaluation for an appropriate treatment plan are crucial for successful management and ultimately determine the patient’s outcome. Key considerations include tear size, location, presence of rootlet herniation, working in a water environment without dead space, and the feasibility of FES suturing, as outlined (Table 2).

Table 2.

Evaluation and surgical workflow in FES treatment of dural tears

Tear size and localization		FES Surgical steps
		1	2	3	4	5
Partial thickness				Clear tear surroundings		Onlay patch, No tissue glue
Axilla or the nerve
Thecal sac	< 5 mm
	> 5 mm  < 10 mm				Inlay patch or Suture
	Herniation of rootlets	Reposition of rootlets	Intradural look
	> 10 mm		Intradural look		Suture
Not accessible
IF CONVERSION	MIS	Watertight and dead space closure
	Open

Limitations

This dural tear evaluation and repair technique was developed specifically for FES through the interlaminar approach with tears located at the posterior or the lateral side. The technique may not apply to other approaches due to differences in instrument design, instrument mobility, dead space, and surgical environment. Open or microtubular techniques often create more dead space, possibly resulting in less favorable outcomes and requiring standard management. Given the limitations of our approach, we recommend avoiding its use under the following conditions.

• Ventral dural tears

• Extensive or complex dural defects

• Concurrent procedures that increase dead space (e.g., endoscopic transforaminal interbody fusion)

• Surgeons with limited experience in endoscopic spine surgery

How to avoid complications

In the setting of FES surgery with continuous fluid irrigation, unrecognized dural tears may result in complications such as rootlet herniation, subdural fluid collections, and potential neurological injury postoperatively. This highlights the need for accurate recognition, thorough evaluation, and appropriate technique selection in managing dural tears. In uniportal FES, the minimal dead space often makes tear patching sufficient for treating small dural tears, with the main goal being to cover the defect and prevent fascicle herniation. Smaller thecal sac tears with a risk of fascicle herniation can be treated with an additional inlay patch. Tears at the nerve root or those that are hard to access can be managed using an onlay patch.

Dural sealants are generally unnecessary in uniportal FES dural repair, as a watertight dural tear closure does not affect clinical outcome. Tissue glue may cause perineural fibrosis [7] and, due to its volume in confined spaces, can compress nerves, risking neurological injury or cauda equina syndrome [2]. Its reduced efficacy in wet environments and potential mass effect further limit its suitability for FES.

When encountering a defect larger than 5–10 mm associated with rootlet herniation, inlay patching or suturing is generally recommended to prevent complications such as CSF leakage or delayed rootlet herniation, which can lead to poor postoperative outcomes [3, 9]. Being prepared for FES dural suturing can help reduce the need for conversion to MIS or open surgery.

A potential limitation to adopting endoscopic dural suturing, even among experienced surgeons, is the lack of a dedicated knot pusher in standard instrument sets. This can be overcome using a self-made knot pusher adapted from a No. 8 drain catheter. The rigid working channel of the endoscope stabilizes the relatively soft catheter while pushing the surgical knot into the working area, making the suturing possible.

Conversion to open surgery remains an option for less experienced surgeons or extensive dural tears. If conversion is decided, managing postoperative CSF-related issues becomes again key to optimal outcomes, often requiring longer bed rest and the use of drains for residual leakage [5].

Specific information for the patient

Dural tear incidence should be disclosed to the patient, along with the management strategy and postoperative care plan. Small tears (< 5 mm) or larger ones (5–10 mm) manageable endoscopically typically do not restrict immediate postoperative ambulation. However, large tears with rootlet herniation requiring conversion to open repair necessitate careful management of postoperative CSF leakage, often involving prolonged bed rest and drainage to ensure optimal outcomes [5].

Summary

1. In FES, limited dead space and continuous irrigation affect dural tear detection, repair techniques, and material choice.

2. Detecting tears under irrigation requires heightened awareness.

3. Assessing tear location, size, and rootlet herniation is key to selecting the appropriate repair method.

4. Uniportal FES management focuses on dural healing and fascicle containment, with watertight closure being less critical.

5. Endoscopic repair is challenging due to restricted access and instrument limitations.

6. Onlay and inlay patching techniques can enhance tear site closure.

7. Fibrin glue is generally ineffective and unnecessary in the FES setting.

8. Suturing in FES is technically challenging but may be aided by the proposed “FES Dural Tear Treatment Kit”.

9. With proper preparation and technique, most dural tears can be managed endoscopically, minimizing the need for open conversion.

10. Open surgery remains a valid option for extensive tears or less experienced surgeons.

Supplementary information

Below is the link to the electronic supplementary material.

Author Contributions

P.V.D., P.C., and B.S. wrote the main manuscript text, P.V.D. and P.C. prepared figures and video. All authors reviewed the manuscript.

Funding

The authors did not receive support from any organization for the submitted work.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethical approval

This study was exempted by the Institutional Review Board of the Faculty of Medicine Vajira Hospital (COE: 021/2025 X) in compliance with international guidelines for human research protection as Declaration of Helsinki, The Belmont Report, CIOMS Guideline, International Conference on Harmonization in Good Clinical Practice (ICH-GCP) and 45CFR 46.101(b).

Competing interests

The authors declare no competing interests.