CASE REPORT
Two Cases of Lumbar Spinal Canal Stenosis with Dorsal Meningovertebral Ligaments: Potential Risk of Dural Laceration
2026 Volume 13 Pages 111-116
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2026 Volume 13 Pages 111-116
Dural laceration is a critical complication in full endoscopic spinal surgery. We need to recognize precise surgical anatomy to avoid it. Recently identified dorsal meningovertebral ligaments, connecting the dorsal spinal dura mater to the ligamentum flavum, may contribute to this risk, but their role remains unclear. We present 2 cases of lumbar spinal canal stenosis treated with full endoscopic laminectomy. In both cases, dorsal meningovertebral ligaments anchored the dura to the ligamentum flavum and were visible through high-resolution endoscopy. Attempts to remove ligamentum flavum fragments caused dural traction via the dorsal meningovertebral ligament, nearly resulting in laceration. We modified our approach by detaching the dorsal meningovertebral ligament before flavectomy, preventing dural injury and ensuring uneventful recoveries. These cases highlight the importance of recognizing dorsal meningovertebral ligament as a potential risk factor for dural laceration during full endoscopic laminectomy. Although the presence of dorsal meningovertebral ligament cannot be predicted preoperatively, the enhanced visualization provided by full endoscopic spinal surgery allows for intraoperative identification. We recommend careful inspection for dorsal meningovertebral ligament before flavectomy during full endoscopic laminectomy. If identified, these ligaments should be detached prior to ligamentum flavum removal to minimize the risk of dural injury. This approach can significantly enhance the safety of the full endoscopic laminectomy procedure and potentially reduce the incidence of dural complications in full endoscopic spinal surgery.
Dural laceration resulting in a cerebrospinal fluid leak is one of the most critical complications in spinal surgery.1-4) The incidence of dural laceration during spinal surgery ranges from 1.6% to 15.8%.2,5-14) This complication leads to increased operative time and can cause serious clinical sequelae during the postoperative period. Dural laceration has been reported to result in a higher rate of wound-related complications.15) Moreover, it can potentially lead to severe neurological consequences, such as hemorrhagic stroke and central nervous system infections.16-19) Although repairing dural tears in conventional spinal surgery is generally manageable, prevention remains paramount. Further, in full endoscopic spinal surgery (FESS), we need to pay extra attention to avoid it because repairing a torn dura mater with FESS is exceptionally challenging, often necessitating conversion to conventional open microscopic or microendoscopic surgery.
A precise understanding of detailed surgical anatomy is crucial for conducting safe surgical procedures.20) However, the anatomical factors contributing to dural lacerations have scarcely been addressed in the literature.21) Recent studies have revealed the detailed anatomical features of ligaments connecting the dorsal spinal dura mater to the ligamentum flavum (LF), termed dorsal meningovertebral ligaments (DMVLs).22,23) These structures have been proposed as a potential cause of inadvertent dural laceration during flavectomy. Nevertheless, this hypothesis stems primarily from cadaveric studies, with a notable lack of clinical evidence from live patients.
In this report, we present 2 cases of lumbar spinal canal stenosis (LSCS) treated with full endoscopic laminectomy (FEL). In both cases, we clearly identified DMVL structures. The high-resolution surgical views afforded by FESS clearly demonstrated the potential risk of dural laceration associated with DMVL, providing valuable insights into this anatomical challenge.
A 68-year-old man presented with intermittent claudication and bilateral posterior thigh numbness. Magnetic resonance imaging (MRI) and computed tomography (CT) revealed mild spondylolisthesis and severe canal stenosis at the L4/5 level (Figure 1a). Dynamic radiography showed no clear instability at this level. The patient was diagnosed with lumbar spinal stenosis (LSS), and FEL was performed.
Preoperative imaging and intraoperative findings of case 1. a) MRI and CT showing severe canal stenosis with mild spondylolisthesis at the L4/5 level. b-d) intraoperative views (right: cranial, left: caudal). b) DMVL anchoring the dura mater to the LF fragment. c) DMVL disconnection using bipolar cautery. d) Post-LF removal, with no dural laceration.
CT: computed tomography; DMVL: dorsal meningovertebral ligament; LF: ligamentum flavum; MRI: magnetic resonance imaging
The FEL procedure was performed as previously described.24) Under general anesthesia, the patient was positioned prone. A 12 mm skin incision was made 10 mm lateral to the midline of the target vertebral level under fluoroscopic guidance. Muscles attached to the adjacent vertebral laminae were carefully detached using a dilator, similar to microendoscopic surgical technique.25) An angled working sheath and a 6.4 mm working channel endoscope were then inserted. The vertebral laminae and articular processes were removed using a 4.0 mm diameter high-speed drill (NSK Nakanishi Japan, Tokyo, Japan) to expose the LF. The LF boundary was dissected, and its central part was carefully separated using a small curette and Kerrison rongeur. After confirming the absence of dural adhesion using a dissector or blunt hook, the separated LF fragments were removed. Following these procedures, the endoscope and working sheath were carefully removed, and a drain was placed. Motor-evoked potential monitoring was performed throughout the procedure.
In this case, during LF fragment removal, a ligament anchoring the dura mater to the separated LF fragment was identified and presumed to be a DMVL (Figure 1b). When attempting to remove the LF fragment, traction on the dura mater via the DMVL was observed, indicating a risk of dural laceration. To prevent this, we disconnected the DMVL using bipolar cautery (Figure 1c). Subsequently, the LF fragment was safely removed without any abnormal movement of the dura mater, and no dural laceration occurred (Figure 1d). These surgical procedures are presented in Video 1. The postoperative course was uneventful, and the symptoms improved.
Case 2A 57-year-old man presented to our hospital with pain in the lateral aspect of the right thigh. MRI and CT showed severe canal stenosis at the L4/5 level (Figure 2a). The patient was diagnosed with LSS, and FEL was performed.
Preoperative imaging and intraoperative findings of case 2. a) Preoperative imaging revealing severe canal stenosis at the L4/5 level. b-d) Intraoperative views (right: cranial, left: caudal). b) DMVL observed under the LF, connecting it to the dura mater. c) DMVL dissection using Kerrison rongeur. d) Safe LF removal without dural laceration.
DMVL: dorsal meningovertebral ligament; LF: ligamentum flavum
The FEL procedure was conducted as described in Case 1. Following the dissection of the LF from the lamina, the central portion of the LF was separated. Upon confirming the absence of adhesion between the dura mater and the LF, we attempted to remove the separated LF fragment. Upon elevating the LF fragment with a Kerrison rongeur, we observed its connection to the dura mater via a ligamentous structure presumed to be a DMVL (Figure 2b). Similar to Case 1, traction on the dura mater occurred via the DMVL when the LF fragment was lifted.
Careful dissection of the DMVL was performed using the Kerrison rongeur (Figure 2c), allowing for safe removal of the LF without dural laceration (Figure 2d). These surgical maneuvers are demonstrated in Video 2. The patient's postoperative course was uneventful, with notable improvement in symptoms.
We present 2 cases of LSCS with DMVL. To our knowledge, this is the first report demonstrating DMVL during FESS. The endoscopic view of FESS clearly elucidates the characteristics and potential risks of DMVL. In Case 1, the operative video vividly illustrates how the DMVL exerted traction on the dural sac during flavectomy. Despite the presence of the DMVL in the surgical field, we initially failed to recognize its connection between the dura mater and the LF. It was the abnormal movement of the dura mater-specifically, its upward displacement-during LF fragment removal that alerted us to this connection. If we had continued to pull up the LF fragment, a dural laceration would have occurred. This case exemplifies how DMVL can potentially lead to dural injury.
Based on our experience with Case 1, we recognized the risk of dural laceration when the DMVL appeared in the surgical field during Case 2. Consequently, after confirming the connection among the DMVL, the dura mater, and the LF, we carefully detached the DMVL, allowing for the safe removal of the LF fragment.
Solaroglu et al.26) were the first to report the presence of ligaments between the dural sac and the LF, which they termed "attention-to-terminal attachment" (ATA) to emphasize the need for caution regarding terminal attachments.26) In their study, which included intraoperative findings from laminoflavectomy for LSCS, these ligaments were observed only at the L5 level. In contrast, Shi et al.22) conducted a cadaver dissection study and reported ligaments connecting the dura mater to the LF or lamina across various levels of the lumbosacral region. They named these ligaments DMVL and suggested that ATA would be a subset of DMVL. In our cases, we identified ligaments between the dura mater and the LF at the L4/5 level and adopted the term DMVL for these structures. We agree with the idea that ATA is part of DMVL and can exist at any level within the lumbosacral region, acknowledging that detailed anatomical assessment in live patients is challenging. Nonetheless, we recognize the significance of the study by Solaroglu et al.,26) as it demonstrated the existence of these ligaments in live patients, a finding lacking in the cadaver study by Shi et al.22)
In both studies, the ATA or DMVL was attached to the cranial side of the dural sac and the caudal side of the LF, running obliquely between them. This suggests that the ATA or DMVL may not be fully dissected even after confirming no adhesion between the dural sac and LF using forceps or a dissector (Figure 3). Indeed, despite checking for adhesions with a dissector, undissected DMVL were identified in both cases. Given this anatomical feature of DMVL, confirming the absence of adhesion to the underlying dura mater with a dissector or blunt hook does not ensure a safe flavectomy. Unexpected dural lacerations can occur during conventional open microscopic surgery or microendoscopic surgery, even after confirming no adhesion between the dura mater and LF. This may also be due to the presence and anatomical characteristics of DMVL. Shi et al.22) reported that DMVLs are most frequently observed at the L4/5 and L5/S levels, which are among the levels where intraoperative dural lacerations occur most frequently.27) These findings support the notion that DMVL and their anatomical features contribute to unexpected dural laceration during decompression surgery for LSS.
Schematic representation of the dural sac and LF adhesion check. Note the oblique orientation of DMVL between LF and the dural sac. Horizontal dissection (blue curved arrows) may not completely dissect the DMVL.
DMVL: dorsal meningovertebral ligament; LF: ligamentum flavum
Dural laceration during FESS is a critical complication because repairing it during FESS is extremely challenging. It may necessitate transitioning from FESS to microendoscopic or microscopic surgery to perform the repair, significantly increasing the invasiveness of the procedure. Conversely, FESS offers a clear and detailed surgical view. The nearly bloodless surgical field during FESS facilitates precise identification and visualization of anatomical structures. Closer positioning of the endoscope allows for observation of more detailed anatomical structures. Furthermore, the characteristics of angled endoscopes facilitate relatively easy visualization of the space between the LF and the dura mater. As demonstrated in this case series, a careful survey of the surgical field before flavectomy can aid in identifying DMVL and potentially prevent dural lacerations. Identifying DMVL before flavectomy may be more challenging during microendoscopic or microscopic surgery than with FESS, as it is difficult to thoroughly survey the layer between the dura mater and LF. Therefore, we believe that FESS is the optimal strategy for preventing dural laceration due to DMVL, despite this being its most critical complication.
A cadaver dissection study reported that the occurrence rate of DMVL was 97% at the L5-S1 level. In our institutional experience, however, we do not observe DMVL at such a high frequency. Given that some fragile DMVL may be disconnected before they are identified intraoperatively, we cannot accurately determine their true incidence in our cases. Further studies will be required to clarify this issue.
Currently, no preoperative study can identify DMVL. Particularly at the level of LSS, we speculate that it is nearly impossible, as even spinal roots or the dura mater are not clearly depicted in MRI or CT myelography, which are among the most detailed preoperative imaging studies available. This limitation underscores the importance of an intraoperative survey to check for the presence of DMVL and enhances the advantages of FESS.
ConclusionDMVLs, which connect the dura mater and the LF, can lead to unexpected dural laceration. Although dural laceration is one of the most critical complications in FESS, the clear and detailed surgical view provided by FESS is invaluable for identifying DMVL before flavectomy. Therefore, it is essential to carefully examine the layer between the dural sac and LF prior to performing a flavectomy.
We extend our sincere gratitude to the operating room staff for their invaluable technical assistance and to the medical record clerks for their diligent efforts in patient data collection. Our appreciation also goes to the radiological department staff for their meticulous recording of CT and MRI data. Additionally, we are grateful to Dr. Takao Yasuhara for coordinating the first author's fellowship at the Iwai Orthopaedic Medical Hospital. Finally, we would like to express our profound gratitude to Dr. Hirohiko Inanami, whose mentorship and guidance have been instrumental to all the authors.
All authors have no conflict of interest.
The patients have provided consent for the submission of this case report to the journal.
