Delayed Presentation of a Middle Meningeal Arteriovenous Fistula after Le Fort I Osteotomy

Abstract

While rare, complications following Le Fort I maxillary osteotomy includes hemorrhage, ischemia, infection, and vascular abnormalities. This study aimed to present an uncommon case of delayed presentation of a middle meningeal pseudoaneurysm formation after Le Fort I osteotomy. The patient initially presented with pulsatile tinnitus, and the pseudoaneurysm was subsequently treated successfully with image-guided embolization.

Introduction

The Le Fort I osteotomy is a commonly used procedure for correcting class III malocclusion in patients with cleft palate; up to 32% of patients with unilateral cleft palate and lip eventually require either a maxillary osteotomy or bimaxillary surgery¹⁾. Complications following Le Fort I maxillary osteotomy is rare, with an overall rate of 6.4%²⁾. Common complications of orthognathic surgery are hemorrhage, ischemia, and infection²⁾; vascular complications such as arteriovenous fistulae (AVF) have been reported only on a few occasions^3-8). The onset of symptoms may be insidious and nebulous, with widely varying signs and symptoms. Nevertheless, the ramifications of aneurysm rupture or thromboembolism necessitate expedient treatment. This study aims to present an uncommon case of delayed presentation of a middle meningeal pseudoaneurysm with arteriovenous fistula formation after Le Fort I osteotomy, presenting as pulsatile tinnitus.

Case Report

The patient was a 21-year-old woman with a previously repaired left-sided Veau class III cleft lip and palate who presented for Le Fort I maxillary osteotomy and sagittal split mandibular setback osteotomy (Figure 1) for functional and aesthetic improvement. The Le Fort I osteotomy was performed using a custom 3D printing cutting guide and fixed with custom 3D-printed plates and screws. This was planned with Materialize CMF (Leuven, Belgium) and Depuy Synthes CMF (Pennsylvania, USA). The osteotomies were performed using reciprocating saws and osteotomes to cut through the maxillary buttresses, maxillary sinus and nasal septum, and pterygoid plate regions. The maxilla was down-fractured using digital pressure on the anterior alveolus of the maxilla while supporting the zygoma. The maxilla was advanced by 5 mm in the anterioposterior direction and the mandible was setback by approximately 8 mm. The operating time was 7 h and 50 min with estimated blood loss at 500 ml. The patient recovered well and was discharged 2 days later.

Figure 1.

Preoperative computer-assisted design (CAD) simulations for mandibular and maxillary movement.

Six weeks after operation, the patient developed right-sided pulsatile tinnitus, described as a “whooshing sound”. While initially attributed to Eustachian tube dysfunction, the persistence of her symptoms prompted computed tomography angiography, which revealed a right maxillary artery pseudoaneurysm with an arteriovenous fistula connecting at the level of the posteromedial parotid. A subsequent angiogram showed a truncated right middle meningeal artery continuation into the pterygoid vein and distal reconstitution of the middle meningeal artery by the accessory meningeal artery (Figure 2). The patient subsequently underwent radiologically guided embolization using the Concerto coiling system (Medtronic, USA) accessed via the common femoral artery. The AVF was coiled from the pseudoaneurysm across its fistulous point to the middle meningeal artery stump. An intra-procedure angiography confirmed the cessation of the fistula (Figure 3). With an immediate resolution of the patient's symptoms post-procedure, she has remained well as of the last review at 18 weeks postoperatively.

Figure 2.

Arteriovenous fistula (labelled AVF) between the right middle meningeal artery (labelled MMA) and pterygoid vein (labelled PV) before embolization.

Figure 3.

Angiography after embolization of the AVF was completed (labelled), middle meningeal artery (MMA).

Discussion

Traumatic vascular injury is a rare complication following Le Fort I osteotomy. This risk is increased in patients with anatomical irregularities and palatal scarring, as commonly encountered in patients with palatal clefts, craniofacial dysplasia, and vascular malformations. Kramer and colleagues'²⁾ analysis of complications after Le Fort I osteotomy showed that the complication rate was considerably higher in patients with anatomical irregularities (25.2%) than in those without anatomical irregularities (3.9%). It is suggested that maxillary retrusion, hypoplasia, and scarring of the palate and pterygoid region increase the likelihood of complications⁶⁾. The time to discovery of vascular complications ranged from as fast as during the immediate postoperative period to as long as 8 months after the index surgery^8,9).

Branches of the internal maxillary artery, such as the middle meningeal artery, are at increased risk of damage due to their close relationship to the pterygomaxillary junction in the pterygopalatine fossa. During pterygomaxillary osteotomy and separation, the pterygoid plate may fracture unpredictably, leading to vascular damage and pseudoaneurysm formation. Pseudoaneurysms may enlarge over time, causing facial swelling, asymmetry, or paresis from an impingement of adjacent nerve. Moreover, they may present the risk of rupture and severe hemorrhage⁹⁾.

In this case, it was believed that the vascular malformation developed due to blunt force trauma when force was applied while using the osteotomes for the Le Fort I or the horizontal cut of the bilateral sagittal split osteotomy. The force applied toward the general direction of the affected blood vessels may have resulted in a partial rupture and subsequent healing by fistula formation. Unlike pseudoaneurysms, AVF has a more indolent clinical course with slow, progressive enlargement and a lower risk of rupture. While typically established immediately post-injury, there may be a latent phase of several weeks before AVF are clinically evident. It is hypothesized that AVF formation occurs after simultaneous, partial lacerations of an artery and a closely located vein, which leads to hemorrhage and hematoma formation. Endothelial proliferation occurs at the hematoma site, developing endothelial-lined channels between the arterial and venous networks⁸⁾. Blood from the high-pressure arterial system is shunted toward the low-flow venous system, and the low resistance in the fistula results in preferential flow across the fistula. This creates the characteristic bruit or thrill; patients may describe this as pulsatile tinnitus due to its close relation to the middle ear⁶⁾.

Treatment options are surgical ligation and radiologically guided embolization. Several papers have described that the treatment of choice for such vascular complications would be the latter because it is minimally invasive and is associated with a low incidence of morbidity. Additional benefits of this approach are the sparing of proximal vessels and stimulation of collateral blood supply formation, limiting bone necrosis¹⁰⁾.

Conclusion

Vascular injury remains a rare but severe complication of orthognathic surgery. A high level of suspicion and close clinical monitoring is required to diagnose and institute early treatment of these complications. Image-guided embolization is the treatment of choice.

Author Contributions: H.C.F., B.H.C., and F.C.L. performed the surgery and follow-up care. S.N. wrote this manuscript.

Conflicts of Interest: There are no conflicts of interest.

Consent for Participation and Publication: Written informed consent was obtained from the patient.