Unveiling The Myth of High Recurrence Rate of Extracranial Arteriovenous Malformations of The Head and Neck: Systematic Review of Case Reports and Case Series

Introduction

Arteriovenous malformations (AVMs) make up a mere 1.5% of all vascular anomalies, and they are frequently found in the head and neck region (47.4%) as well as the extremities (28.5%). There are two main types of AVMs: focal and diffuse. Focal AVMs appear as soft tissue mass and are generally diagnosed during infancy or childhood. They possess a single arterial feeder, distinct borders, and a nidus. These types of AVMs typically respond well to appropriate treatment. In contrast, diffuse AVMs extend across and tend to disrupt tissue boundaries. They are more often identified in older children and adults. Diffuse lesions are more challenging to treat due to their multiple feeding vessels, necessitating close monitoring and repeated interventions.^1,2

Although AVMs are not malignant, they can be locally aggressive and destructive, leading to complications such as severe disfigurement, ulceration, massive haemorrhage, pain and, in the worst cases, heart failure. These anomalies have tendencies to expand, occasionally undergoing sudden increases in growth, influenced by factors like trauma, hormonal changes, or iatrogenic causes The diagnosis was established based on medical history, physical examination, and usually confirmed by MR-angiography or CT-angiography.^3,4

The treatment of AVMs is still controversial; there are no staging criteria or standardized guidelines, and treatment options vary from a conservative approach to more aggressive strategies. In the past, surgical excision was the predominant approach compared to endovascular embolization therapy for arteriovenous malformations (AVMs). However, the current trend is to limit surgical excision to small, localized AVMs due to the unacceptable risk of significant bleeding associated with the procedure. Endovascular embolization treatment often require multiple sessions for comprehensive closure of the AVM. When endovascular treatment is not followed by a surgical phase, potentially leading to recurrences after the natural degradation of embolic materials. A multidisciplinary approach with a combined treatment based on endovascular embolization and surgical excision is a good compromise and is rated a good choice by several studies.^5–7

In this context, we present the outcomes of various modality treatment for management AVMs in the head and neck. The main objective of this research was to perform a comprehensive analysis of existing literature concerning the recurrence of head and neck AVMs following treatment. Our goal was to identify the most effective treatment option with a lower recurrence rate

Methods

We conducted an extensive and systematic literature review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our study was registered in PROSPERO: CRD42023490871 on December 17, 2023. We identified suitable studies using the online search engines PubMed, Scopus, and ScienceDirect. The keywords for the search are “Arteriovenous Malformations”, “AVMs”, “Head and Neck”, “Endovascular”, “Surgical”. All clinical studies targeting treatment, outcome, complication and recurrence of AVMs of the head and neck were included in the primary review. Retrospective and prospective English studies, as well as case reports published between January 2000 and October 2023 were included. There were no restrictions as to the country of origin, clinical setting or size of the institution in which the treatments were performed. We did not set a minimum sample size of the studies, as any clinical findings or experience in treatment might be of value to clinicians or future studies. We excluded reports that did not specified the therapy used and follow up period.⁸ We also excluded patients that were loss to follow up and reported still undergoing treatment. First and second author reviewed the title, abstracts and full-text and discussed which literatures to include and exclude in the review. If authors encountered confusion, a third and fourth author were consulted to establish a consensus.

The data that this study collected including age, gender, location of AVMs, imaging modality, history of previous intervention, treatment modality, follow up period, recurrences and complications. Our analysis focused on key endpoints, specifically the recurrence rates of head and neck arteriovenous malformations following various treatment approaches. As interventional therapy of AVMs of the head and neck details on gender, age, of the treated patients were inconsistently reported, they did not undergo analysis.

Results

Our search generated a total of 162 citations, and identified a total of 108 potentially relevant articles. Of these articles, a total of 51 articles merited full text review. Based on the above-listed inclusion and exclusion criteria mentioned in our PRISMA figure ( Figure 1), a total of 20 articles were included in the analysis. From the 20 articles, 83 patients ( Table 1) were deemed suitable for inclusion in the literature review.

Figure 1. PRISMA flow diagram of the study.

The reviewed articles demonstrated that appropriate diagnostic tests were documented among the 83 patients, a total of 79 individuals, accounting for 95%, utilized angiography, CT, or MRI, either individually or in combination, for diagnosing AVMs ( Table 2). Among the clinicians, the most preferred modalities were MRI, with 68 cases (82%), and angiography, with 62 cases (75%).

31 individuals among 83 patients, or 37.3%, had previously undergone treatment. This indicates a recurrence rate of 37.3% among the reported cases of AVMs in the head and neck region. It’s important to note that the treatment methods used were evenly distributed among the endovascular approach, surgical approach, and a combination of endovascular and surgical approaches. with 22.6%, 38.7%, 36.7% subsequently ( Table 3).

Out of the 83 reported patients, the combination of endovascular and surgical approach emerged as the most favored method. We identify notably 46 or 55.4% of patients underwent a combined approach involving both endovascular and surgical methods, while 21 patients (25.3%) opted for a surgical-only approach, and only 16 patients (19.3%) pursued an endovascular-only approach. With an average follow-up period of 26 months, combined approach exhibited a remarkable outcome with a 0% recurrence rate. In contrast, the endovascular approach had a 12.5% recurrence rate, and the surgical approach showed a 14.2% recurrence rate, making the combination approach the most successful in preventing AVM recurrence ( Table 4).

Out of the 83 cases, 27 complications were reported, representing a complication rate of 32.5%. The surgical approach alone demonstrated the lowest complication rate, with only 2 cases (9.5%). In contrast, the endovascular approach and the combination of endovascular and surgical approach had complication rates of 37.5% and 41.3%, respectively ( Table 5). The most prevalent complication was wound dehiscence, occurring in 11 out of the 27 cases with complications, making up 40.7% of the reported complication cases ( Table 6).

Discussion

A clinical diagnosis of arteriovenous malformation is diagnosed through the patient’s medical history, physical examination and supportive examination are crucial especially MRI and angiography. MRI currently serves as the definitive method for assessing the extent of involvement within tissue planes and illustrating flow characteristics. Angiography plays a vital role in revealing the feeding vessels, offering insights into anastomoses with other extracranial or intracranial vessels, and providing details about the venous drainage pattern for ‘super selective’ embolization. During embolization, the focus should be on the nidus or epicenter of the arteriovenous malformation rather than the proximal feeding vessels.⁴

Complete removal of AVMs is imperative to prevent recurrence. To achieve this, a customized approach must be devised for each patient, taking into consideration the specific boundaries of the lesion. The excision process may involve the removal of three different structures: fascia, muscle, and bone. In cases where preoperative embolization has not been performed, extended resection into apparently normal tissue is advised to ensure the thorough elimination of the AVMs.⁹

The management of AVMs remains the most debated aspect in the medical literature, with no universally accepted approach. Previously, the treatment methods were evenly distributed among the endovascular approach, surgical approach, and a combination of endovascular and surgical approaches.¹⁰ Currently, the preferred treatment involves selectively embolizing vessels combined with surgical resection and subsequent reconstruction of soft tissues. The primary goal of preoperative embolization is to minimize blood loss and enhance the surgical procedure, emphasizing that it should not be seen as a method for reducing the extent of resection. It is crucial not to postpone surgical resection beyond 48 hours after embolization, as the inflammation that ensues makes the hemodynamic benefits ineffective and renders the surgery more challenging.¹⁰

Recurrence of AVMs has been reported in as much as 80% of cases following embolization or resection. In cases where the nidus is incompletely removed or embolized, there is a heightened risk of aggressive growth in the remaining lesion, leading to a potential progression risk as high as 50% within the initial five years.¹ In recent literature findings, the recurrence rate of AVMs that managed with combined approach of both endoscopic and surgical approach give a remarkable outcome with a 0% recurrence rate. This result most likely because the surgeons are able to obtain a clear surgical vision field and completely excise the AVMs mass margin, as a result of the pre-embolization of the AVMs mass. The presence of a clear margin and minimal bleeding likely contributes to this successful outcome.

Recurrence of AVMs is often associated with neovascularization driven by factors such as hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). These factors are upregulated in hypoxic conditions, promoting the recruitment of endothelial progenitor cells and new vessel formation.¹¹ The use of well-vascularized tissue in reconstruction is essential for avoiding post-excisional ischemia, which can trigger collateralization, parasitization, and neovessel recruitment from the surrounding mesenchyme, contributing to AVM recurrence. Evidence indicates that free flaps, offering a robust and uniform blood supply, are significantly more effective in preventing recurrence compared to pedicled flaps or skin grafts. One study highlighted a 0% recurrence rate with free flaps, in contrast to a 64% recurrence rate with pedicled flaps and grafts. Additionally, patients undergoing reconstruction with free flaps after wide local excision achieved markedly better functional and aesthetic outcomes, with 87.5% reporting good-to-excellent results and no recurrences observed during the follow-up period.¹²

Currently, in our literature search, the management of AVMs mass shows a lower recurrence rate than previously believed. However, the average follow-up period was 26 months. In some literature recurrences have been observed a decade after treatment, highlighting the essential need for extended post-treatment follow-up to ensure timely detection. It’s crucial to acknowledge that the interpretation of the term “cure” varies in the literature, and reported instances of “cure” may be influenced by limited follow-up periods. Some cases defined “cure” as an asymptomatic state following embolization rather than a complete absence of the condition.^1,13

Conclusion

The multi-modality of endovascular and surgical approaches has a lower recurrence rate of AVM masses compared to a single-modality treatment. These findings highlight the importance of a comprehensive and multidisciplinary approach in contributing to the successful surgical outcomes of these complex vascular anomalies.

Ethics and consent

Ethical approval and written informed consent were not required.