Description of included study

A total of 221 articles were identified during the literature search. Seventy-one duplicates were identified and removed, and 150 titles and abstracts were screened. Finally, 35 articles were reviewed, of which 18 met the inclusion criteria of this review (Fig. 1).

Fig. 1

Flow diagram for study selection

Table 1 summarises the included studies and their major findings with regard to craniofacial-orbital distortions and ophthalmic manifestations. All studies were retrospective, reviewing patients’ CT scans, MRIs, and medical records. Three studies each were conducted in the United States of America [32,33,34] and the United Kingdom [20, 35, 36], two studies each were conducted in India [12, 27] and Taiwan [14, 37], and one study each were from South Korea [38], China [39], Iran [40], Saudi Arabia [41], Japan [4], Italy [42], Tunisia [11], and Morocco [3].

As outlined in Table 1, most of the studies were of morphological assessment of orbital distortion and ophthalmic manifestations, except for the study of Tailor et al. [20] which combined morphological and morphometry assessments. The sex distribution of participants diagnosed with PNS mucoceles in the included studies was given for almost all the studies except for the studies of Makihara et al. [4], Bouatay et al. [11], Van Tassel et al. [32], and Sadiq et al. [35] that did not give information on the sex distributions in their studies. Ten of the included studies had more males in their sex distribution of patients with PNS mucoceles [20, 33, 34, 36,37,38,39,40,41,42], three studies had more females [12, 14, 27], while one study gave an equal number of the sex distribution of patients with PNS mucoceles [3].

Table 1 Table of characteristics of included studiesRisk of bias assessment of the included studies

The ROB assessment for each study is summarized in Table 2. Domain 1 (objective(s) and subject characteristics), all (100%) of the included studies were of low ROB [3, 4, 11, 12, 14, 20, 27, 32,33,34,35,36,37,38,39,40,41,42]. Domain 2 (study design), all (100%) of the included studies were of low ROB [3, 4, 11, 12, 14, 20, 27, 32,33,34,35,36,37, 39,40,41,42,43]. Domain 3 (characterization of methods), all (100%) of the included studies were of high ROB [3, 4, 11, 12, 14, 20, 27, 32,33,34,35,36,37,38,39,40,41,42]. Domain 4 (descriptive anatomy), 94.44% of the included studies had low ROB [3, 4, 11, 12, 14, 20, 27, 32, 33, 35–42, and 5.56% had high ROB [34]. Domain 5 (results reporting), 94.44% of the included studies had a low ROB [3, 4, 11, 12, 14, 20, 27, 32, 33, 35,36,37,38,39,40,41,42], and 5.56% had a high ROB [34].

Table 2 Risk of bias assessmentPNS mucoceles identified in the included studies

From the 18 studies included in this review, a total of 638 patients (661 sides) were identified to be diagnosed with different types of PNS mucoceles, with males being the highest incidence of patients. Frontal sinus, ethmoid sinus, and fronto-ethmoidal mucoceles had the highest incidences (26.36%, 24.03%, and 23.29%, respectively), while the spheno-ethmoidal mucoceles had the lowest incidence (Fig. 2).

Fig. 2

Bar chart showing incidences of the types of PNS mucoceles identified in the included studies

PNS mucoceles and orbital bony defect

Craniofacial-orbital bony defects were reported in seven studies, mostly occurring in patients with frontal and ethmoidal sinus mucoceles [4, 11, 12, 32,33,34, 36]. Distortion, disruption, and breach of the lamina papyracea (the thin bony plate that forms the medial wall of the orbit), orbital wall erosion, and skull base erosion were the most reported craniofacial-orbital bony defects caused by PNS mucoceles [11, 12, 33, 36]. Intra-orbital extension, orbital bone expansion, and destruction and remodelling of the forehead requiring reconstruction were also reported [32,33,34]. Furthermore, an incidence of 97% of orbital involvement with intracranial extension and skull-base erosion was documented [12, 33, 34] (Table 1).

PNS mucoceles and ophthalmic manifestations

Different types of ophthalmic manifestations and complications were reported in all the 18 studies included in this review, having to occur in any type of the PNS mucoceles (but more common in mucoceles in the anterior sinuses). Almost all the included studies reported proptosis, diplopia, ptosis, preorbital swelling, and exophthalmos. Few studies reported vision problems/symptoms, ocular movement problems, and epiphora [12, 14, 37, 39, 41], while Makihara et al. [4] reported Type I, II & III orbital complications of sinusitis.