The pterygopalatine fossa (PPF) and infratemporal fossa (ITF) are located behind the maxillary sinus, providing a natural corridor for endoscopy to access these areas (1–6). Various endoscopic approaches to the ITF have been previously described, such as an endoscopic sublabial transmaxillary approach, an endoscopic Denker approach, an endoscopic endonasal transmaxillary approach, and a contralateral transseptal transmaxillary approach (7–9). Although endoscopic approaches are substantially less invasive than conventional approaches, they can still lead to several sequelae, including nasolabial groove collapse, superior alveolar numbness, and over-resection of nasal structures. It is well-known that nasal structures are critical for maintaining the physiological functions of the nasal cavity. An over-resection of nasal structures, such as the middle nasal concha, the inferior nasal concha, the nasal septum, or the total lateral wall of the nose, could severely affect the physiological functions of the nasal cavity and even induce conditions such as empty nose syndrome and depression, imposing heavy psychological and physical burden on patients. The endoscopic transnasal prelacrimal recess transmaxillary approach (PLRMA) is an improved endoscopic endonasal transmaxillary approach that enters the maxillary sinus through a submucosal dissociation of the nasolacrimal duct (10–12). The benefits of this approach include preventing superior alveolar numbness and the development of cosmetic issues, as well as preserving the integrity of mucosa on the nasal lateral wall. However, endoscopic anatomical evidence for the area of exposure and the surgical freedom of this modified approach remains scarce (13, 14). In this study, we aim to evaluate the feasibility of the PLRMA approach to the PPF and ITF and share our surgical experience through case illustrations.

The endoscopic transnasal PLRMA was performed bilaterally on three fresh silicon-injected heads. Dissections were carried out using a 30° endoscope, burrs, dissector blades, and standard endoscopic instruments (Kal Storz, Tuttlingen, Germany). Images were captured using an AIDA HD system (Karl Storz, Tuttlingen, Germany). High-resolution computed tomography (CT) scans were performed on each specimen, and the dataset was imported into a surgical navigation system (Ariemedi Medical Technology Co., Ltd, China). A navigation probe was used to identify the boundary of exposure on the posterior wall of the maxillary sinus, and the area of exposure was calculated using a navigation software.

The mean area of exposure of the PLRMA was 9.6 cm², and the mean working width was 3.35 cm (Table 1).

The endoscopic endonasal PLRMA was used in six patients. The average age of patients was 45.8 years (range 24–61 years). The current report included two categories of lesions: schwannoma (four patients) and epidermoid cyst (two patients). All six lesions were confined to the PPF or ITF without extending into adjacent areas. Total resection was achieved in each patient. After the operation, the patients were instructed to wash the nasal cavity with sea salt water 3–5 times a day for 1 month to prevent sinusitis. The mean follow-up time in our series was 16 months. One patient experienced postoperative facial numbness for 3 months. Two patients had mild postoperative sinusitis, characterized by a short-course stuffy nose, which resolved within 2 weeks. None of the six patients developed empty nose syndrome (Table 2).

Several variations of endoscopic transmaxillary approaches have been described for accessing the ITF and PPF, such as an endoscopic Caldwell–Luc approach, an endoscopic Denker approach, a contralateral transseptal approach, and a medial maxillectomy approach (14, 15). While the endoscopic transmaxillary approaches can provide adequate exposure in the ITF and PPF, they are often accompanied by various surgical complications, such as superior alveolar numbness, nasolabial groove collapse, and even empty nose syndrome, due to the over-removal of nasal structures. Empty nose syndrome, in particular, can induce severe psychological and physical effects on patients and may even lead to psychological conditions such as anxiety and depression. To reduce the invasiveness of the endoscopic transmaxillary approach, some scholars (16) have proposed modified transmaxillary approaches through the inferior meatus or prelacrimal recess to access the maxillary sinus. Zhou et al. reported the resection of tumors in the PPF and ITF through an endoscopic prelacrimal recess approach (PLRA) (10–12). This modified transmaxillary approach helps gain entry into the maxillary sinus through submucosal medial maxillectomy after freeing the nasolacrimal duct, thereby allowing access to the maxillary sinus, while preserving the integrity of the mucosa of the lateral nasal wall. In addition, this method does not injure the superior alveolar nerves and prevents the development of cosmetic issues. In this study, we evaluated the anatomical rationality of this modified transmaxillary approach, called the endoscopic transnasal prelacrimal recess transmaxillary approach, using endoscopic anatomy and a navigation system.

In this study, five extreme anatomical landmarks were selected on the posterior wall of the maxillary sinus and the anterior wall of the PPF, forming a pentagon. This pentagon represents the area of exposure of the PLRMA. The PLRMA provided seemingly adequate exposure not only of the PPF but also of the most medial aspect of the posterior wall of the maxillary sinus (Figure 2). The differences in the areas of exposure in sublabial anterior maxillectomy and the Denker approach, as well as medial maxillectomy, have been described by Carrau et al. (17, 18) and Little et al. (19, 20), separately. Our measurement of the exposure area was conducted following Little’s method. The mean exposure area of the PLRA was 9.6 cm². Little previously compared the ipsilateral endonasal approach, the Caldwell–Luc approach, and the contralateral endonasal transseptal approach using a navigation probe. The exposure areas of the posterior wall of the maxillary sinus through these approaches were 10.4, 9.9, and 10.0 cm², respectively. A comparison of the data showed that the exposure area of the PLRMA was similar to those of the other approaches. Although we did not conduct a quantitative comparison with other endoscopic transmaxillary approaches, the constraint of the nasolacrimal duct was removed. We believe that the lateral exposure of the PLRMA on the posterior wall of the maxillary sinus will be slightly better than that of the traditional medial maxillectomy.

The mucosa of the lateral nasal cavity serves essential physiological functions such as warming and humidifying the air in the nasal cavity, as well as increasing air resistance. Excessive damage to nasal cavity structures, such as turbinectomy or an extensive resection of the lateral wall of the nasal cavity, can lead to permanent postoperative nasal cavity discomfort in the form of nasal congestion, nasal dryness, pterygopalatine neuralgia, chest distress, wheezing, and even empty nose syndrome. Prolonged discomfort can induce depression in patients. Therefore, greater attention should be given to better preserving the physiological functions of the nasal cavity. While traditional endoscopic transmaxillary approaches offer adequate exposure to the ITF and PPF, they often require sacrificing the turbinates, ethmoidal cells, the posterior part of the nasal septum, and a significant amount of nasal mucosa. The major advantage of the PLRMA lies in preserving the integrity of the nasal cavity mucosa when accessing the maxillary sinus. This is achieved by suturing the mucosa directly at the head end of the inferior concha, preserving the morphology of the turbinate. Therefore, the PLRMA is better suited for protecting the physiological functions of the nasal cavity.

The PLRMA is essentially a modified endoscopic transmaxillary approach that provides access to the maxillary sinus through submucosal medial maxillectomy. Although the advantage of the PLRMA lies in preserving the integrity of the nasal cavity mucosa, as mentioned previously, this approach has limitations concerning its expansion capability on the medial and lateral sides. For tumors of different types and locations, the selection of approaches should be individualized. Giant or invasive malignant tumors such as nasopharyngeal carcinoma and adolescent angiofibroma require an extensive resection of the lateral nasal wall structures, and even multiple approaches need to be used in combination. However, for benign tumors with relatively small sizes, such as the schwannoma and epidermoid cyst, the PLRMA could ensure complete tumor resection, while preserving nasal cavity functions as much as possible. This provides more options for endoscopic access to the ITF and PPF.

The endoscopic transnasal prelacrimal recess transmaxillary approach can offer sufficient exposure to the pterygopalatine fossa and infratemporal fossa, allowing for the complete preservation of the integrity of the nasal mucosal structure, while avoiding excessive resection of nasal cavity components.