1 Introduction
Maxillary artery (MA), a key vessel supplying the sinonasal and skull base area, can be occluded before tumor manipulation during surgeries to reduce bleeding, clarify the surgical field, aid in tumor resection, and minimize complications
[1]. MA occlusion has been applied in traditional open surgeries. However, literature on endoscopic occlusion of this artery is limited. This study explores the anatomical basis and feasible surgical techniques for endoscopic pre-occlusion of the MA using cadaveric anatomical studies, as a fundamental basis for further application in surgeries for sinonasal and skull base tumors.
2 Materials and Methods
Gross anatomical dissections were performed on three fresh-frozen, latex-injected cadaveric head specimens (6 sides). Subsequently, endoscopic observations were conducted via trans-buccal, trans-maxillary, and endonasal approaches to simulate intraoperative endoscopic views. The arteries and veins in the specimens were perfused with red and blue silicone, respectively. The dissections were performed in the Anatomy Laboratory of the Research Units of New Technologies of Endoscopic Surgery in Skull Base Tumor (2018RU003), Chinese Academy of Medical Sciences, located at the Eye Ear Nose and Throat Hospital of Fudan University.
Gross anatomical photographs were documented using a Fujifilm GFX100s digital camera, while endoscopic anatomical images were captured with the XION MATRIX P Spectra 3D endoscopic imaging system equipped with a 0° 4mm lens.
Gross anatomical dissection was conducted as follow: facial soft tissues were removed to expose the bony anterior wall of the maxillary sinus. A bony window was created in the anterior wall to access the maxillary antrum. The posterolateral wall of the maxillary sinus was removed, and adipose in the buccal, pterygopalatine, and infratemporal regions was cleared to expose the vasculature, nerves, and muscular structures. Endoscopic examination was performed through trans-buccal, trans-maxillary, and endonasal approaches to visualize the pterygopalatine and infratemporal fossae, with particular attention to the MA and its branches, as well as their relationships with surrounding anatomical structures.
Typical cases of endoscopic MA pre-occlusion via different approaches in sinonasal and skull base surgeries were presented to illustrate these procedures in surgical practice. In the majority of cases, ligation and division of the MA (or its main branches) were integral steps for adequate tumor exposure and access to the surgical field; these maneuvers were not performed as an additional discretionary intervention.
This study was approved by the Institutional Ethics Committee of the Eye Ear Nose and Throat Hospital of Fudan University (approval No. 2023106). The use of human cadaveric specimens for anatomical dissection was conducted in accordance with the institutional guidelines and relevant national regulations. Written informed consent was obtained from all individual patients (or their legal guardians) for the publication of any associated images and clinical data.
3 Results
3.1 Gross anatomy
During gross anatomical dissection, utilizing the aforementioned approach, the posterolateral wall of the maxillary sinus and the adipose tissue of the infratemporal and pterygopalatine fossae were removed stepwise. This dissection exposed the temporalis muscle and the buccal nerve, which was found attached to its medial aspect. The buccal nerve was then traced as it coursed between the superior and inferior heads of the lateral pterygoid muscle to reach the anterior trunk of the mandibular nerve.
The main trunk of the MA consistently lay between the inferior head of the lateral pterygoid and the temporalis muscle. The MA was observed to cross the buccal nerve in a cruciate manner, proceeding medially to enter the pterygomaxillary fissure. Subsequently, it branched into the infraorbital artery, the posterior superior alveolar artery, the sphenopalatine artery, and the descending palatine artery (Figure 1a-c).
3.2 Endoscopic anatomy
3.2.1 Endoscopic trans-maxillary approach view
From the trans-maxillary sinus perspective, the posterior superior alveolar branches were seen traversing the posterior sinus wall, partly overlying the MA. Retracting the posterior superior alveolar artery laterally provided clear exposure of the MA emerging between the temporalis muscle and the inferior head of the lateral pterygoid muscle. The buccal nerve coursed along the medial aspect of the temporalis muscle, intersecting with the MA in a cruciate manner near the origin of the buccal artery (Figure 2a, b).
3.2.2 Endoscopic endonasal approach view
The endonasal route gave us a slightly more medial view. After entering the maxillary antrum through the prelacrimal recess, we retracted the posterior superior alveolar artery laterally to expose the MA. The MA was identified between the temporalis muscle and the inferior head of the lateral pterygoid muscle, with this midline perspective offering a slightly more medial viewpoint compared to the trans-maxillary approach (Figure 2c, d).
3.2.3 Endoscopic trans-buccal approach view
When working through the buccal corridor, we dissected the buccal fat pad and infratemporal fat posteriorly along the maxillary lateral surface. The buccal nerve was identified ascending along the medial edge of temporalis muscle, then turning backward to course along the medial aspect of the temporalis muscle before passing through the superior and inferior heads of the lateral pterygoid muscle. A characteristic cruciate relationship with the MA was observed. In the specimen illustrated, the buccal nerve crossed below the MA (Figure 2e, f), though crossing above the artery was also observed in other specimens (Figure 2g).
3.3 Indications of different surgical approaches for endoscopic MA occlusion
Depending on the extent of lesion invasion, the endoscopic endonasal, trans-maxillary, or trans-buccal approaches may be selected.
Endoscopic trans-buccal approach is applicable when pathological involvement of the maxillary antrum obstructs direct anatomical access. It allows for simultaneous ligation of the MA and delineation of the lateral boundary for tumor resection. An incision is made in the mucobuccal fold or buccal mucosa, followed by dissection and removal of the buccal fat pad to expose the lateral wall of the maxilla. Dissection along the lateral aspect of the maxilla creates a pathway to the infratemporal fossa. Further removal of the adipose tissue in the infratemporal fossa exposes the temporalis muscle and the inferior head of the lateral pterygoid muscle. Dissection between these structures sequentially reveals the buccal nerve and the MA. The temporalis muscle, lateral pterygoid muscle, and buccal nerve serve as reliable landmarks for identifying the main trunk of the MA.
Endoscopic trans-maxillary approach is particularly recommended for pathological lesions confined to the pterygopalatine and/or infratemporal fossae, provided the maxillary sinus is not involved, thus preserving the integrity of the sinus pathway during surgery. A Caldwell-Luc procedure is performed via the mucobuccal fold to access the maxillary sinus. The posterior wall of the maxillary sinus is then removed to enter the infratemporal fossa. After clearing the adipose tissue in the infratemporal fossa, the temporalis muscle, the inferior head of the lateral pterygoid muscle, and the buccal nerve along the medial aspect of the temporalis are exposed. Using the buccal nerve, temporalis muscle, and inferior head of the lateral pterygoid muscle as reliable anatomical landmarks, the main trunk of the maxillary artery is identified for subsequent ligation.
Endoscopic endonasal approach is particularly suitable for lesions located in the paramedian region, as it provides direct access with significantly reduced tissue trauma compared to other approaches. This approach involves endoscopic medial maxillectomy or prelacrimal recess approach via the nasal cavity. The steps of exposing and removing the posterior wall of the maxillary sinus to access the infratemporal fossa, clearing adipose tissue, and identifying and ligating the MA are similar to those in the transmaxillary approach.
Techniques for MA ligation include bipolar electrocautery, suture ligation, plasma knife, arterial clipping, and monopolar electrocautery.
3.4 Clinical outcomes of endoscopic MA pre-occlusion
A total of 20 patients (14 males, 6 females; mean age 49.8 ± 19.6 years) underwent endoscopic MA pre-occlusion prior to tumor resection. Tumor involvement rates were: nasal cavity (0.90), nasopharynx (0.15), maxillary sinus (0.85), pterygopalatine fossa (0.70), infratemporal fossa (0.65), orbit (0.60), and facial tissue (0.15). Mean preoperative hemoglobin was 130.00 ± 22.37 g/L, and mean postoperative hemoglobin was 110.39 ± 21.05 g/L (mean gap 19.67 ± 14.91 g/L) (Table 1). Only two patients (10%) required perioperative blood transfusion. No occlusion-related complications, such as facial numbness, trismus, or delayed bleeding, were observed in any of the enrolled cases. However, the lack of a control group and the small sample size should be considered when interpreting this safety profile.
3.4.1 Pre-occlusion of the MA via the trans-buccal approach
Case 1: A 74-year-old female was diagnosed with malignant transformation of inverted papilloma in the left maxillary sinus. Enhanced MRI revealed a 2.8 cm × 2.9 cm × 3.0 cm tumor involving the posterior wall of the left maxillary sinus, the pterygopalatine fossa, and the infratemporal fossa (Figure 3a, b). The left MA was identified as the major feeding artery, without tumor invasion. Under general anesthesia, the left infratemporal fossa was accessed along the lateral aspect of the left maxilla, and the left MA was occluded before proceeding with the partial resection (Figure 3c–f). Intraoperative bleeding was approximately 150 mL, and postoperative MRI confirmed complete tumor resection.
3.4.2 Pre-occlusion of the MA via the trans-maxillary approach
Case 2: A 17-year-old male with a neoplasm in the posterior left nasal cavity. Enhanced MRI and CT scans revealed a 3.7 cm × 4.4 cm lesion in the left nasopharynx, involving the left sphenoid sinus, pterygopalatine fossa, infratemporal fossa, with significant enhancement. The diagnosis of juvenile nasopharyngeal angiofibroma was confirmed, with left MA identified as the main feeding artery (Figure 4a–d). No preoperative embolization was performed.
The tumor was resected endoscopically via trans-maxillary sinus approach. The MA was occluded before tumor manipulation (Figure 4e–h). The tumor was extracted through the oropharynx, with intraoperative bleeding of approximately 200 mL. Postoperative MRI confirmed complete tumor resection.
3.4.3 Endoscopic endonasal occlusion of the MA
Case 3: A 39-year-old female, three years post-radiotherapy for nasopharyngeal carcinoma, presented with imaging suggesting recurrence. Preoperative MRI indicated thickening of the nasopharynx and enhancement in left pterygopalatine fossa, infraorbital fissure, and foramen rotundum, involving the adjacent skull base bone (Figure 5a–d). The major blood supply was the left MA.
Endoscopic endonasal approach through the prelacrimal recess was performed. The posterior wall of maxillary sinus was drilled to access the pterygopalatine and infratemporal fossa. Plasma ablation was used to resect adipose tissue, revealing the tumor in the pterygopalatine fossa, as well as the lateral pterygoid muscle and the temporalis muscle. The MA was identified and occluded using plasma coagulation. The tumor was then resected endoscopically (Figure 5e–h). Postoperative imaging confirmed complete tumor resection.
3.4.4 Endoscopic-assisted open approach before the mandible ramus for MA occlusion
Case 4: A 69-year-old male presented with recurrent of right maxillary sinus carcinoma five months after subtotal maxillectomy followed by radiotherapy and five cycles of oral capecitabine chemotherapy, all of which had failed, leading to extensive tumor progression (Figure 6a). Enhanced MRI revealed the tumor involving the right facial skin, orbit, and hard palate, measuring 7.8 cm × 8.3 cm × 11 cm, with significant enhancement and the main blood supply originating from the right MA (Figure 6b). Using an endoscopic-assisted open approach, the coronoid process of the mandible was removed to access the infratemporal fossa between the tumor and the mandible. After occluding the MA, the tumor and orbital contents were resected en bloc, with negative margins confirmed by frozen section. An anterolateral thigh flap was used to repair the defect (Figure 6c–h). Intraoperative bleeding was approximately 500 mL. Postoperative imaging confirmed complete tumor resection.
4 Discussion
Surgery in the sinonasal and skull base regions demands meticulous hemostasis because of the dense neurovascular network. Good visibility is the cornerstone of safety, and excessive bleeding not only obscures the field but also increases the risk of complications
[2]. Strategies to minimize bleeding include preoperative evaluation, anesthesia considerations, systemic medication, and surgical techniques
[1,
3]. Preemptive localization and occlusion of feeding arteries effectively reduce bleeding in sinonasal and skull base tumor surgeries and lower complication rates, especially in vascular diseases like juvenile nasopharyngeal angiofibroma
[2,
3].
The MA, which supplies the pterygopalatine fossa, infratemporal fossa, sinonasal, and skull base areas, is divided into the mandibular, pterygoid, and pterygopalatine segments
[4]. The pterygoid segment is closely associated with the inferior head of the lateral pterygoid muscle. Anatomical studies by Rhoton et al. found that 80% of this segment is located lateral to the inferior head, while 20% is medial
[4]. Maeda et al.
[5] found in a cadaveric dissection study that 90.4% of the pterygoid segment runs lateral to the lateral pterygoid muscle. The pterygopalatine segment passes through the superior and inferior heads of the lateral pterygoid muscle, moving forward, inward, and upward through the pterygopalatine fissure to enter the pterygopalatine fossa
[4].
Occluding the MA or its branches is commonly used to treat epistaxis, including interventional arterial embolization and surgical procedures
[6-
8]. Interventional arterial embolization is a minimally invasive procedure that offers precise blood flow blockage, but it also comes with the drawbacks of needing high-quality equipment, contrast agents, radiation exposure, and carries risks such as revascularization and potential complications including stroke, ophthalmic injury, tissue ischemic necrosis, and pain
[9,
10]. Traditional surgical methods for MA occlusion include the trans-maxillary (trans-antral) approach
[11] and the intraoral-extramaxillary sinus approach
[12]. Wang et al.
[13] applied MA pre-occlusion in open surgery for maxillary malignancies, finding significantly less intraoperative bleeding. Occluding the MA also eliminated the previous emergency situations in maxillectomy where rapid specimen removal and hasty hemostasis were required
[13]. In open surgery, the MA’s deep position often obscures its identification. Endoscopy overcomes this limitation by providing bright, magnified views through narrow corridors, so we can pinpoint the artery before tumor manipulation and occlude it with greater precision. It provides advantages of avoiding the requirement for interventional arterial embolization or open approach, leading to less surgical injuries and intraoperative bleeding, improved surgical visualization, lower costs, reduced complications, as well as higher surgical efficacy.
Literature reports that endoscopic occlusion of the MA is primarily used for treating refractory epistaxis, with the surgical approach mainly being endoscopic endonasal. This involves enlarging the maxillary sinus ostium endoscopically, removing the posterior wall of the maxillary sinus to expose the MA for further occlusion
[14-
16]. Mahmoud et al.
[17] found through cadaveric dissection that the endoscopic trans-orbital infraorbital fissure approach could successfully ligate the MA, but no clinical application cases have been reported. Polev et al.
[18] were the first to use endoscopic intraoral ligation of the MA in surgery for nasal skull base tumors, achieving good control of intraoperative bleeding. Their surgical approach is similar to the open intraoral-extramaxillary sinus approach
[12].
Due to the diverse involvement of nasal skull base tumors, different surgical approaches are utilized to occlude the MA. For lesions located in the nasal cavity, ethmoid sinus, pterygopalatine fossa, infratemporal fossa, and the skull base, an endoscopic trans-maxillary sinus approach for MA occlusion can be chosen, passing through the uninvolved maxillary sinus cavity to remove the posterior wall. Infratemporal fossa adipose is removed to expose the MA. For lesions significantly involving the maxillary sinus impeding access through the antrum, an endoscopic trans-buccal approach can be utilized. By incising the buccal mucosa and removing buccal and infratemporal fossa fat, the MA is revealed between the inferior head of the lateral pterygoid muscle and the temporalis muscle. This approach can be seamlessly integrated into the endoscopic procedure for dissecting the lateral margin of the tumor, without additional surgical procedures. In our case series, we observed a hemoglobin gap before and after surgery, which we attribute to the difficulty in accurately estimating intraoperative blood loss due to the extensive flushing of the endoscope and the surgical field. If the space between the maxilla and the mandible is insufficient to expose the MA, partial removal of the mandible and/or maxilla can be performed to enlarge the surgical corridor.
The endoscopic occlusion offers several practical benefits. It curbs tumor perfusion at source, which translates into less operative bleeding and, in many of our patients, transfusion avoidance
[19]. Moreover, it spares the patient the added risks and expenses of preoperative embolization, including contrast reactions and radiation exposure
[8]. Under endoscopy, anatomical structures can be closely observed, the surgical field is clear, and MA occlusion can be achieved under direct vision, which helps protect surrounding important anatomical structures and avoid postoperative complications. Endoscopy allows for MA occlusion through narrow anatomical corridors, and an individualized surgical approach can be designed based on the lesion, making it a minimally invasive operation with minimal trauma and fast postoperative recovery. However, endoscopic MA occlusion is not suitable for all sinonasal and skull base tumors. Preoperative enhanced imaging should be carefully reviewed to confirm the extent of the lesion, the anatomical area that needs to be removed, and whether the lesion’s blood supply majorly originates from the MA, before finalizing the surgical plan. For lesions that significantly encircle the MA or are located in front of it, it is not suitable to block the MA under endoscopy through the maxillary sinus or trans-buccal approach.
5 Limitations
We acknowledge several limitations. This was a single-center retrospective series without a control arm, and our patients had diverse tumor types and stages. Moreover, the anatomical data came from only three cadavers, so the reported variation rates should be interpreted with caution. These factors inevitably introduce selection bias, and our conclusions should therefore be viewed as preliminary evidence of feasibility rather than proof of superiority.
6 Conclusion
Endoscopic MA pre-occlusion can be considered a primary step in surgical procedures such as sinonasal and skull base tumor resection to minimize intraoperative bleeding. Trans-buccal, trans-maxillary, endonasal, and endoscopic-assisted open approaches are selected based on the extent of lesion invasion and surgical needs. In our experience, endoscopic MA pre-occlusion is technically straightforward, well tolerated, and cost-sparing. We consider it a useful addition to the hemostatic armamentarium for selected sinonasal and skull base tumors.
The Author(s). This article is published by Higher Education Press at journal.hep.com.cn.
This is an open access article distributed under the Creative Commons Attribution License 4.0 (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
PDF
(34792KB)
