Abstract

Background: Trigeminal neuralgia (TN) is often treated with microvascular decompression (MVD), providing long-term pain relief for most patients. However, a subset experiences recurrence requiring reoperation. Endoscopic MVD techniques have gained traction due to enhanced visualization and potentially lower morbidity, yet their feasibility for redo procedures – particularly in complex cases with dense adhesions – remains uncertain.

Case Description: We report the case of a 63-year-old male who initially presented with Barrow Neurological Institute (BNI) grade V TN in the V2–V3 distribution. After an endoscopic MVD, the patient achieved immediate pain relief (BNI I) but developed recurrent symptoms 10 months later (BNI III), controlled by carbamazepine. A subsequent escalation (BNI IV) prompted surgical re-exploration. Imaging revealed no residual or new neurovascular conflict. Instead, intraoperative findings demonstrated dense adhesions tethering the trigeminal nerve to the tentorium, causing nerve tension. Careful endoscopic dissection restored nerve mobility and resulted in complete symptom resolution.

Conclusion: This case highlights the feasibility and effectiveness of a fully endoscopic redo MVD in recurrent TN where dense adhesions, rather than persistent vascular compression, were the primary mechanism of recurrence. Further investigation is warranted to optimize endoscopic techniques, reduce adhesion formation, and improve long-term outcomes in redo MVD cases.

Keywords: Adhesion-induced nerve tension, Endoscopic microvascular decompression, Recurrent trigeminal neuralgia, Redo microvascular decompression

INTRODUCTION

Microvascular decompression (MVD) remains a mainstay surgical treatment for trigeminal neuralgia (TN), offering promising long-term outcomes and high rates of pain relief.[ 1 - 4 ] Recently, endoscopic MVD has emerged as a viable alternative to the traditional microscopic approach, potentially offering superior visualization of neurovascular structures with reduced invasiveness.[ 2 , 4 ]

Despite these advantages, recurrent TN still occurs in a subset of patients following MVD, necessitating reoperation.[ 3 , 4 , 6 ] Common reasons after microscopic MVD for recurrence include incomplete decompression, development of new or persistent vascular conflicts, and adhesion formation that can tether and place tension on the trigeminal nerve.[ 5 , 6 , 8 ] Redo MVD procedures present additional challenges due to scarring and altered anatomy.[ 6 , 11 ] While fully endoscopic techniques have been increasingly utilized in primary MVD, their feasibility in redo surgeries – especially in the presence of dense adhesions – remains uncertain.[ 7 , 9 , 10 ]

In this report, we highlight the case of recurrent TN symptoms 2.5 years after an initial endoscopic MVD. We describe the operative findings, surgical technique, and successful outcome of redo endoscopic MVD and discuss the potential role of this minimally invasive approach in the management of recurrent TN.

CASE PRESENTATION

A 63-year-old male initially presented with Barrow Neurological Institute (BNI) grade V trigeminal pain in the right V2–V3 distribution. He underwent endoscopic MVD 2.5 years ago [ Figure 1 ], achieving BNI grade I (complete relief) immediately postoperatively. The patient remained pain-free at 1-month and 3-month follow-up visits, with a BNI pain intensity score of Grade I (no pain, no medication). However, 10 months after the first surgery, his symptoms returned at BNI grade III (persistent pain, controlled with medications). At that time, carbamazepine was prescribed and controlled with medications. Despite partial relief for up to 10 months, his pain again escalated over the past month (BNI grade IV).

Figure 1:

Initial three-dimensional (3D) image and surgical findings of the initial high-definition endoscopic microvascular decompression. (a) 3D reconstruction image shows neurovascular conflict on the root entry zone (REZ) of the trigeminal nerve (V) by the superior cerebellar artery (SCA), pons (P), facial (VII) and vestibulocochlear (VIII) nerves. Nearby vessels, the posterior cerebellar artery (PCA) and the basilar artery (BA) are also shown. (b) Endoscopic view of V and SCA at the REZ; note the pons (P), tentorium (Tr), and petrous surface (Pf). (c) After temporary transferring of the SCA loop from REZ of V with Micro-Dissector (D) and adjacent neuroanatomical structures, including the petrosal surface (Pf), tentorium (Tr) and pons (P). (d) Final view demonstrating decompression of the trigeminal nerve (V) by transposing the SCA onto the tentorium (Tr), achieving clear separation from the nerve and adjacent neuroanatomical structures, including the petrosal surface (Pf) and pons (P).

Neurological examination upon his recent admission revealed no deficits aside from trigger-zone sensitivity in the maxillary and mandibular divisions. Preoperative imaging included high-resolution three-dimensional (3D) fast imaging employing steady-state acquisition and constructive interference steady-state sequences, which confirmed the absence of new vascular compression or pathological lesions [ Figure 2a ]. As medical therapy had become insufficient, he opted for redo surgical exploration.

Figure 2:

Initial three-dimensional imaging and endoscopic surgical findings. (a) Preoperative 3D reconstruction showing neurovascular conflict at the root entry zone (REZ) of the trigeminal nerve (V) caused by the superior cerebellar artery (SCA). Adjacent anatomical landmarks include the posterior cerebral artery (PCA), basilar artery (BA), pons (P), facial (VII) and vestibulocochlear (VIII) nerves. (b) Skin marking for the 1.5 cm keyhole retrosigmoid craniectomy. (b1) Intraoperative photo showing minimal bone removal through the keyhole opening. (c) Endoscopic view of the trigeminal nerve (V) and SCA before adhesion release. The petrosal surface (Pf), tentorium (Tr), and pons (P) are visualized. (d) Final surgical view following transposition of the SCA onto the tentorium (Tr), achieving decompression and separation of the nerve from surrounding structures including the Pf and P.

Operative findings and management

Under general anesthesia, we reopened the previous incision [ Figure 2b ] and performed a 1.5 cm keyhole craniectomy in the retrosigmoid region [ Figure 2b1]. Using a 0° endoscope, we navigated to the trigeminal nerve entry zone under 4K endoscopic system visualization. Upon inspection, no new arterial loops or venous compressions were observed-unlike many redo-MVD cases, where residual or new vascular compression is frequently implicated. Instead, the nerve appeared to be densely adherent to the tentorium, creating tension along the cisternal segment of TN [ Figure 2c ].

Care was taken to preserve the integrity of the trigeminal nerve fibers, minimizing traction. Once the adhesions were fully lysed, the nerve regained mobility, with no obvious compression remaining [ Figure 2d ]. The wound was closed in a standard multilayer fashion.

Postoperatively, the patient experienced a complete resolution of TN symptoms. He was discharged with no new neurological deficits.

DISCUSSION

Recurrent TN after MVD can result from persistent or new vascular conflicts, adhesion formation, or incomplete initial decompression.[ 4 , 6 ] Before deciding to proceed with a redo surgery, it is crucial to thoroughly evaluate potential anatomical or surgical causes of recurrence. In this case, magnetic resonance imaging (MRI) with 3D reconstruction image clearly showed no residual or new arterial contact at the root entry zone of the trigeminal nerve, effectively ruling out persistent neurovascular compression by the superior cerebellar artery. Moreover, it was known that Teflon had not been inserted during the initial endoscopic MVD, thus Teflon-induced granuloma or foreign body complications could be excluded. It was confirmed from the initial surgical records and intraoperative video documentation that Teflon or other synthetic interpositional materials were not used during the first procedure.

Despite eliminating vascular re-compression and Teflon-related issues, adhesion-induced nerve tension remained a plausible cause of recurrence. However, adhesions or micro-scar formations are notoriously difficult to visualize on conventional MRI sequences, underscoring the diagnostic challenge of distinguishing adhesions as a primary etiology of postoperative pain. In many instances, the decision to re-explore is driven by clinical symptoms, the absence of overt vascular conflict on imaging, and the possibility of microscopic anatomical factors – like adhesion-related tethering – that do not readily appear on MRI.

During surgery, surgeons often encounter fibrotic tissue and distorted anatomical landmarks, creating intraoperative visibility challenges that elevate the risk of complications.[ 5 , 6 , 11 ] While some advocate for a larger retrosigmoid craniotomy to address these difficulties, minimally invasive endoscopic approaches have shown promise in reoperations.[ 2 , 4 , 10 ] In this patient’s case, detailed inspection revealed dense adhesions tethering the trigeminal nerve to the tentorium – a lesion that was not visible on preoperative imaging. Lysis of these adhesions alone was sufficient to alleviate pain, highlighting the potential for adhesion-induced nerve tension to perpetuate neuralgia even in the absence of a clear vascular offender.[ 5 , 6 ]

Ultimately, this case illustrates the importance of a thorough preoperative assessment and the consideration of adhesions as a possible cause of recurrent TN when conventional imaging fails to show persistent compression. Endoscopic redo MVD, with its high-definition visualization and targeted dissection capabilities, can effectively address such adhesions while minimizing exposure-related morbidity. Our findings support growing evidence that endoscopic assistance allows for superior illumination and panoramic visualization, enabling the detection of subtle adhesions or compressive elements that may not be evident under microscopic view alone. However, surgeon experience with endoscopic anatomy, especially in scarred operative fields, remains a key determinant of success.[ 8 - 10 ]

Various studies have examined transposition versus interposition techniques for vessel mobilization, reporting similar mid-term outcomes while emphasizing the need to prevent nerve contact or tethering.[ 9 , 10 ] However, neither approach is entirely free from adhesion formation, which can develop over time and lead to recurrent symptoms.[ 5 , 6 , 11 ] Further investigations are warranted to reduce adhesion formation, optimize surgical materials (e.g., Teflon vs. other nonstick materials), and refine endoscopic approaches to minimize recurrence.[ 3 , 4 , 7 ]

CONCLUSION

This case illustrates the feasibility and effectiveness of redo endoscopic MVD in a patient with recurrent TN due to adhesion-induced nerve tension. Preoperative imaging confirmed the absence of persistent vascular compression, yet adhesions – difficult to detect radiologically – proved to be the main mechanism of recurrence. Further studies are necessary to refine endoscopic techniques and optimize outcomes in redo MVD cases.

Ethical approval:

Institutional Review Board approval is not required.

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

Acknowledgments:

The authors wish to thank Ms. Mai Okubo, practitioner nurse of the neurosurgical department, for her invaluable assistance with patient care and administrative support.

References

1. Ashraf M, Sajjad F, Hussain SS, Cheema HA, Ali S, Umar H. Long-term outcome of microvascular decompression for typical trigeminal neuralgia with autologous muscle: An analysis of 1025 patients from a developing country. J Neurosurg. 2024. 141: 849-59

2. Bendtsen L, Zakrzewska JM, Abbott J, Braschinsky M, Di Stefano G, Donnet A. European academy of neurology guideline on trigeminal neuralgia. Eur J Neurol. 2019. 26: 831-49

3. Chen F, Niu Y, Meng F, Xu P, Zhang C, Xue Y. Recurrence rates after microvascular decompression in patients with primary trigeminal neuralgia and its influencing factors: A systematic review and meta-analysis based on 8,172 surgery patients. Front Neurol. 2021. 12: 738032

4. Cho DY, Chang CG, Wang YC, Wang FH, Shen CC, Yang DY. Repeat operations in failed microvascular decompression for trigeminal neuralgia. Neurosurgery. 1994. 35: 665-70

5. Jiao L, Ye H, Lv J, Xie Y, Sun W, Ding G. A systematic review of repeat microvascular decompression for recurrent or persistent trigeminal neuralgia. World Neurosurg. 2022. 158: 226-33

6. Liu J, Li F, Wu G, Liu B, Zhou J, Fan C. Long-term retrospective analysis of re-do microvascular decompression in patients with hemifacial spasm. Front Neurol. 2021. 12: 687945

7. Sindou M, Leston JM, Decullier E, Chapuis F. Microvascular decompression for trigeminal neuralgia: The importance of a noncompressive technique--Kaplan-Meier analysis in a consecutive series of 330 patients. Neurosurgery. 2008. 63: 341-50 discussion 350-1

8. Uhl C, Faraj L, Fekonja L, Vajkoczy P. Transposition versus interposition method in microvascular decompression for trigeminal neuralgia: Midterm analysis of both techniques in a single-center study. J Neurosurg. 2024. 140: 1777-84

9. Uhl C, Vajkoczy P. Contact-free transposition and interposition techniques for trigeminal neuralgia: A systematic review. J Neurosurg Sci. 2023. 67: 36-45

10. Wang B, Zhang L, Yu Y. Treatment of redo-microvascular decompression or internal neurolysis plus microvascular decompression for recurrent trigeminal neuralgia: A review of long-term effectiveness and safety. J Int Med Res. 2022. 50: 3000605221080721

11. Zhao Z, Chai S, Xiao D, Zhou Y, Gan J, Jiang X. Microscopic versus endoscopic microvascular decompression for the treatment of hemifacial spasm in China: A meta-analysis and systematic review. J Clin Neurosci. 2021. 91: 23-31