Maxillary Sinus (MS) Retention Cysts (RCs) are usually asymptomatic and often present as chance findings on imaging.1,2 However, recent studies have demonstrated relationships between MSRCs and various symptoms, such as headaches, facial pain, nasal discharge, and postnasal drip.3–7 MSRCs are generally self-limiting, with spontaneous regression and disappearance rates of 17.6%–38%, but a few continue to gradually increase in size.3 Although some studies have demonstrated no significant correlations between cyst size and symptoms, surgical removal remains recommended for symptomatic RCs.5–9

Traditionally, symptomatic RCs have been treated by puncture and aspiration through the inferior meatus or ostium, or by removal using the Caldwell-Luc approach8,9; however, these procedures have been replaced by endoscopic Middle Meatus Antrostomy (MMA) and Ostiomeatal Complex (OMC) removal.4,5,7 In recent years, some authors have reported that MMA does not provide adequate access to the entire MS and limited the use of some instruments, resulting in residual and recurrent lesions (e.g., inverting papillomas and fungal maxillary sinusitis),10–14 but Inferior Meatus Antrostomy (IMA) provides visibility and access to areas inaccessible with the MMA approach and reduces recurrence.13,14 The objective of this study was to compare the recurrence rates and symptomatic relief of RCs between MMA alone and IMA combined with basal mucosa electrocoagulation.

During the 7-year study period, 107 cases (41 men and 66 women) of unilateral symptomatic MSRCs were analyzed. Patients had a mean age of 43.8 years (range: 21–68 years). There were 39 (36.4%) left-sided and 68 (63.6%) right-sided RCs. Of the 107 patients, 46 (43.0%) were referred from the neurology department, 19 (17.8%) were referred from the stomatology department, and 42 (39.3%) presented directly to the otolaryngology department. Regarding the chief complaint, 71 (66.4%) patients presented with ipsilateral facial pressure or pain, or headache; 25 (23.4%) patients presented with nasal discharge and postnasal drip; and 11 (10.3%) patients presented with nasal obstruction. The mean duration of symptoms was 16.19 months (standard deviation: 7.53; range: 4–73 months).

RCs are generally considered self-limiting, and most cases are treated conservatively. However, some RCs may cause clinical symptoms. Wang et al.3 reported nasal obstruction, nasal discharge, and headaches in 52.5%, 35.7%, and 2.5% of the MSRC patients, respectively. In a study of symptomatic RCs by Hadar et al.,4 headaches were reported by 63% of the patients. Albu et al.5 reported facial pressure or pain as the major symptom (60%) of RCs. In the present study, headaches were the most common symptom, and most patients were referred from the neurology department. We found that 43.0% of the patients initially presented to the neurology department for headaches, while 17.8% presented to the stomatology clinic with facial pain or pressure; these patients were subsequently diagnosed with RCs on CT.

Surgical removal is recommended for symptomatic RCs.3–6,16 In this study, all RCs were symptomatic and required surgical removal. This study demonstrated significant symptomatic improvement after surgical RC removal. Although establishing a relationship between symptoms and MSRCs is difficult,17 our results suggest that RC removal could provide symptomatic relief, in agreement with the findings in previous studies. Hadar et al.4 reported symptomatic improvement in 92% of symptomatic MSRCs after ESS. Albu5 reported symptomatic improvement in 88.8% of cases after MMA. In addition, Behrbohm and Sydow18 demonstrated that RCs > 1.5cm in size significantly delay mucus transport within the MS; these RCs increase the risk of chronic maxillary rhinosinusitis. Cyst removal can restore the altered mucociliary clearance.18 Thus, surgical removal should be considered for symptomatic RCs.

This study found no significant correlations between symptomatic improvement and surgical type. Unsurprisingly, reduced intracystic pressures after surgical intervention led to symptomatic improvement. Similar to the results of previous studies, we did not find any pairwise relationships between symptomatic failure and RC size or the ratio of RC to antral size.3,5 Further investigations are needed to determine whether the symptoms of RCs are related to anatomical variations of OMC. Bhattacharyya15 found no correlation between OMC obstruction and the occurrence of RCs. Albu5 also found no significant differences between the rates of OMC obstruction in control and cyst sides in symptomatic cases. In the present study, patients with substantial anatomical variations of OMC were excluded; no significant differences in OMC anatomies were found between groups. The OMC was not addressed in the IMA group. These findings suggest that RCs may be the main cause of the symptoms.

In recent years, some scholars have found that specific MS lesions (e.g., mucoceles, inverting papillomas, and fungal infections) have higher recurrence rates when treated using the MMA approach. IMA and modified IMA approaches have some advantages for these diseases, particularly for lesions on the inferior, medial, and lateral MS walls.12–14,18 The MMA approach does not completely expose the MS walls and limits the use of certain instruments, such as radiofrequency ablation and drills; this increases the risk of recurrence.13,14 Despite the enhanced field of view with extended MMA, it remains difficult to use rigid instruments at the anterior and inferior regions, as well as the prelacrimal and alveolar recesses. Beswick et al.19 demonstrated that despite the use of a combination of shavers with different angles, only 81% of the MS surface area could be accessed through a large MMA. Govindaraju et al.20 found significantly less residual disease in the anterior, anterolateral, and inferomedial aspects of the MS when IMA was performed, compared with MMA. An endoscope IMA approach provides unobstructed visualization of the inferior, medial, and lateral walls; it also facilitates instrumentation.

Previous studies have suggested that RCs are mostly located in the inferior half of the MS. Wang et al.3 reported that 70% of RCs were in the floor, 20.9% were in the lateral walls, and only 2% were in the superior wall. Albu5 reported that 70% of RCs were in the floor of the MS, while 25% were in the medial, lateral, or anterior wall. In the present study, 70.1% of RCs were in the inferior wall, 10.3% in the medical wall, while only 1.9% were in the superior wall. These RC locations make the IMA approach preferable. In addition, the medial wall of the MS is thin, particularly near the inferior turbinate, and provides easy access for the instruments. Usually, large IMA openings are not required to identify RC attachment sites. IMA provides a generally straight access route, which may shorten the operation time. This study found significantly shorter operating times when IMA was performed, compared with MMA.

The disposable monopolar electrocoagulation device can be curved as necessary to form different angles; it allows access to various areas of the MS. In this study, mucosal stripping of the attachment site was performed to remove the entire mucocele. The attachment areas were then cauterized using an electrocoagulator to achieve complete ablation of the cyst wall and preservation of the healthy mucosa, thereby avoiding recurrences. However, similar to the results of previous studies,5 we found that surgical outcomes were independent of surgery type. Notably, the MMA approach had higher recurrence rates, compared with the IMA approach, which could increase patient anxiety and medical costs.

The realization of the mucoperiosteal flap before antrostomy was made in the IMA technique. The mucoperiosteal flap should be carefully preserved and restored to cover the floor and the medial wall defect of IMA antrostomy, which is an important detail to prevent the postoperative occlusion of IMA. In present study, the persistent patency of IMA was obtained in 67.9% of IMA surgeries. Although the IMA openings had higher closure rates, compared with MMA openings in this study, the closure of the opening was not correlated with recurrences of cysts or symptoms. In the IMA group, four patients with symptomatic failure did not have cyst recurrence or antrostomy closure, while one patient with cyst recurrence did not have closure or symptomatic recurrence. Unfortunately, we noticed that most closures were caused by the medial MS mucosa, rather than the lateral nasal mucosa. This suggests that the medial mucosa of the MS opening also should be preserved and used to cover the lateral nasal wall, thereby preventing closure.

Theoretically, the presence of an open IMA is the potential mucus recirculation between inferior antrostomy and main Ostia of the MS, it could result in the persistence of symptoms, especially for the posterior drip. In this study, 4/53 IMA patients presented symptomatic failures, but only one patient had persistence posterior drip. Surprisingly, the patient showed the closure of IMA. Previous study suggested that the MS secretions will be transported toward the natural ostium even in the presence of a previously placed large and patent IMA.21 The IMA does not disturb mucociliary clearance and the post-operative nasal condition, on the contrary, it might contribute to improved mucociliary function.12,22 Some scholars found that the double pathway yields good postoperative airflow, which enables a good outcome in a patient with fungus ball maxillary sinusitis.23 The limitations of this study were its small sample size and the short follow-up duration of 12-months.

IMA combined with basal mucosa electrocoagulation and MMA alone provided similar symptomatic relief, but IMA had shorter operation times and lower postoperative recurrence rates.

The author declares no conflicts of interest.