Successful 10-year long-term follow-up after artificial dural patch suturing for iatrogenic dural defect created during spinal arachnoid cyst resection: a case report

Abstract

Introduction and importance:

Spinal arachnoid cysts (SACs) are rare intraspinal lesions containing cerebrospinal fluid (CSF). Symptomatic SACs require surgical decompression, but excision can be complicated by iatrogenic dural tears (incidental durotomy), which occur in 1–17% of spinal surgeries. Effective, watertight closure is critical to prevent CSF leakage, infection, and recurrence. Long-term data exceeding 5 years on artificial dural patch repairs are scarce.

Case presentation:

A 50-year-old female presented with severe low back pain and left-leg radiating pain. Magnetic resonance imaging (MRI) revealed a T2-hyperintense intradural cystic lesion at L2–3 compressing the cauda equina, consistent with an arachnoid cyst. She underwent L2–3 posterior decompression and posterolateral fusion with microscopic cyst excision. During adhesiolysis, a significant dural tear occurred. The defect was repaired using a suturable artificial dural patch to achieve watertight closure. Postoperative recovery was uneventful. At the 10-year follow-up, the patient remained asymptomatic, and MRI confirmed a stable repair without cyst recurrence or pseudomeningocele.

Clinical discussion:

The imaging features supported a symptomatic intradural SAC. Literature mandates surgical intervention for symptomatic cases but emphasizes meticulous dural repair to minimize CSF leak risks. Our findings align with systematic reviews suggesting patch-reinforced closure yields lower leak rates (5.5%) compared to suture alone. The 10-year stability validates the biocompatibility and durability of the artificial patch.

Conclusion:

Artificial dural patch suturing delivered excellent, durable outcomes over a decade after intradural cyst excision. This technique is recommended for managing complex dural defects to ensure long-term success.

HIGHLIGHTS

• Spinal arachnoid cysts are rare intradural lesions causing myelopathy, and their excision carries a risk of incidental durotomy.

• We report a 10-year follow-up of a patient who underwent artificial dural patch repair for a large iatrogenic dural defect.

• The patient remained asymptomatic, with no radiological recurrence, pseudomeningocele, or infection over the decade.

• Watertight closure reinforced with a suturable artificial patch is a durable strategy for managing extensive dural defects.

• This case provides rare, long-term evidence supporting the safety and biocompatibility of synthetic dural substitutes in the spine.

Introduction

Spinal arachnoid cysts (SACs) are uncommon expansile lesions within the spinal canal, accounting for approximately 1–3% of all spinal space-occupying lesions^[1,2^]. While often asymptomatic, they can cause progressive myelopathy or radiculopathy due to mass effect^[3^]. The etiology is variable, ranging from congenital malformations to secondary causes like trauma or inflammation^[4^]. Surgical management, typically involving fenestration or complete excision, is indicated for symptomatic cases but carries inherent risks, primarily incidental durotomy (ID)^[5^].

ID is a frequent complication in lumbar spine surgery, with incidence rates reported between 1 and 17%^[6,7^]. Inadequate repair can lead to cerebrospinal fluid (CSF) leakage, intracranial hypotension, pseudomeningocele, and, notably, a significantly increased risk of postoperative infection^[8^]. While primary suture is standard, extensive or irregular defects often necessitate reinforcement with dural substitutes. Current evidence supports the use of patches to reduce leakage rates^[9–11^], yet literature confirming the long-term (>10 years) durability and safety of these artificial materials in the spine is limited.

This report describes a successful 10-year follow-up of a patient who underwent artificial dural patch suturing for an iatrogenic defect during SAC resection.

Presentation of case

We aim to demonstrate the long-term efficacy of this repair technique in preventing recurrence and complications, in accordance with the SCARE 2025 guidelines^[12^]. A 50-year-old female presented to the emergency department on 7 September 2015 with a 3-month history of severe low back pain and radiating pain in the left lower extremity. She reported neurogenic claudication with a markedly reduced walking distance but denied bowel or bladder dysfunction. There was no history of recent trauma.

Clinical findings

Physical examination revealed a positive straight leg raise test (right 70°/left 30°). Motor strength of the left extensor hallucis longus was graded 4/5, while the right was 5/5. Mild hypoesthesia was noted in the left L3 dermatome. Deep tendon reflexes were symmetrical.

Diagnostic assessment

Lumbar spine magnetic resonance imaging (MRI) revealed a well-defined intradural cystic lesion extending from the L2/3 disc level to the L3 inferior endplate (1.4 × 1.1 × 2.4 cm). The lesion showed CSF-equivalent signal intensity (T2 hyperintense and T1 hypointense) without contrast enhancement, compressing the cauda equina and displacing the L3 nerve root laterally (Fig. 1). Concomitant degenerative changes included lumbar spondylosis and multi-level disc herniations. The preoperative diagnosis was a symptomatic intradural extramedullary arachnoid cyst at L2–3 and a herniated intervertebral disc.

Figure 1.

Preoperative and 10-year follow-up magnetic resonance imaging (MRI) of the lumbar spine. (A) Preoperative sagittal T2-weighted MRI showing a well-defined, hyperintense intradural cystic lesion located at the L2–3 level, compressing the cauda equina. (B) Preoperative axial T2-weighted MRI demonstrating the arachnoid cyst occupying the spinal canal and displacing the nerve roots, causing severe stenosis. (C) Postoperative sagittal T2-weighted MRI obtained at the 10-year follow-up. The image confirms the complete resolution of the cyst and sustained decompression of the spinal canal, without signs of recurrence or pseudomeningocele.

Therapeutic intervention

On 10 September 2015, the patient underwent L2–3 posterior decompression and posterolateral fusion (PLF) with microscopic cyst excision. A midline durotomy was performed to access the cyst. During meticulous adhesiolysis to separate the cyst wall from the nerve roots, an irregular dural tear occurred due to dense arachnoid adhesions. Primary suture alone was deemed insufficient to ensure a watertight seal without compromising the neural elements. Therefore, the defect was repaired using a suturable artificial dural patch reinforced with 6-0 nylon sutures (Fig. 2). A watertight seal was confirmed by an intraoperative Valsalva maneuver up to 40 mmHg. The spine was stabilized with pedicle screws and autologous bone graft.

Figure 2.

Intraoperative photographs showing the dural repair technique. (A) Intraoperative view of the surgical field showing an irregular dural defect that occurred during the dissection and removal of the adherent arachnoid cyst wall. (B) The dural defect was successfully repaired using a suturable artificial dural patch. The patch is secured with sutures to ensure a watertight closure and prevent cerebrospinal fluid leakage.

Follow-up and outcomes

The postoperative course was uncomplicated. Subfascial drains were removed on postoperative day (POD) 5, and the patient was mobilized early without symptoms of CSF leakage (e.g., postural headache). She was discharged on POD 14. At 6 weeks and 6 months, her radicular pain had resolved, and motor function had normalized. The patient returned for a 10-year follow-up in 2025. She remained asymptomatic with full neurological function. Follow-up MRI confirmed complete resolution of the cyst, a stable fusion, and an intact dural repair with no signs of pseudomeningocele, recurrence, or foreign body reaction (Fig. 1)

Discussion

Pathophysiology and management of SACs

SACs are thought to enlarge via a one-way valve mechanism that traps CSF or through active secretion by the cyst wall. This pathophysiology supports surgical excision over simple aspiration, which has high recurrence rates^[4^]. Differentiation from spinal arachnoid webs, which show the “scalpel sign” on MRI, is crucial, as webs require lysis rather than resection^[13,14^]. In this case, complete excision was necessary to remove the valve mechanism, and the 10-year absence of recurrence validates this approach.

The challenge of ID

ID is a significant intraoperative challenge. A 2025 meta-analysis by Babasiz et al^[7^] highlighted that ID increases the risk of postoperative infection by nearly fourfold^[8^]. This shifts the paradigm of ID management from merely preventing headaches to deep surgical site infections. Prompt and thorough repair is essential.

Efficacy of artificial dural patches

The choice of repair technique is critical. A systematic review analyzing 776 cases demonstrated that the combination of primary closure with a patch or graft resulted in the lowest CSF leakage rate (5.5%), significantly superior to sutures alone (17.6%) or sealants alone (22.1%)^[7,8^]. While autologous grafts (fat and muscle) are traditional, they require additional harvesting. Synthetic patches offer consistent strength and availability^[8^]. Our case utilizes a suturable artificial patch, which provides mechanical stability that non-suturable onlay patches or sealants may lack in large defects^[15^].

Long-term implications

The 10-year follow-up is the distinguishing feature of this report. Most studies offer limited follow-up (1–2 years), leaving questions about the long-term biocompatibility of synthetic dural substitutes^[16^]. The absence of late complications, such as chronic arachnoiditis, inflammatory granulomas, or delayed cyst recurrence in our patient, suggests that modern artificial patches are safe and durable for long-term spinal implantation^[17,18^]. This supports the aggressive management of dural defects with patch reinforcement to ensure definitive closure. Furthermore, the stable long-term outcome aligns with findings that instrumental fusion (PLF) provides durable clinical improvement for degenerative instability over decades^[19,20^].

Conclusion

Watertight dural patch suturing during intradural arachnoid cyst excision is a safe and effective technique that yields excellent long-term outcomes. This 10-year follow-up confirms the durability of artificial patches in preventing CSF leakage and recurrence without adverse long-term sequelae. Surgeons should prioritize reinforced repair techniques for complex dural defects to minimize postoperative morbidity.

Ethical approval

This case study was approved by the Institutional Review Board of Sanggye Paik Hospital (SGPAIK 2025-10-004). The approval date is 22 October 2025.

Consent

Written informed consent was obtained from the patient’s parent for the publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Sources of funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author contributions

D-.J.L.: Study concept, design, data interpretation, data curation, data collection, data analysis, and writing the paper. J-.Y.J.: Data collection, data curation, investigation, and writing the paper.

Conflicts of interest disclosure

The author has no conflicts of interest to declare.

Research registration unique identifying number (UIN)

1. Name of the registry: Research Registry. 2. Unique identifying number or registration ID: researchregistry11711. 3. Hyperlink to your specific registration (must be publicly accessible and will be checked): https://www.researchregistry.com/browse-the-registry/#home/registrationdetails/693b39d1a1d978e1b60b20e2/.

Guarantor

Dong-Ju Lim, MD, PhD (Department of Orthopaedic Surgery, Seoul Spine Institute, Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Republic of Korea), who accepts full responsibility for the work and the conduct of the study, had access to the data, and controlled the decision to publish.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Data availability statement

Data sharing is not applicable to this article. As this is a single-patient case report, no datasets were generated, and additional individual patient data cannot be shared in order to protect patient privacy and confidentiality, in accordance with the institutional policy of Sanggye Paik Hospital (IRB SGPAIK 2025-10-004).