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IntroductionChronic maxillary atelectasis (CMA), also known as silent sinus syndrome, refers to a persistent decrease in sinus volume from retraction of the maxillary sinus walls due to negative maxillary sinus pressures. Many cases of this syndrome present with spontaneous, asymptomatic enophthalmos due to osseous deformations of the maxillary sinus wall, though some patients have associated nasal and sinus symptoms. Computed tomography (CT) scans demonstrate unilateral maxillary sinus opacification and collapse with inferior bowing of the orbital floor. Resolution of silent sinus syndrome through functional endoscopic sinus surgery alone has not been previously reported.

Case presentationWe report on a 28 year-old female with chronic sinusitis, right chronic maxillary atelectasis (CMA) and ipsilateral enophthalmos. CT/MRI confirmed ipsilateral enophthalmos. Functional endoscopic sinus surgery (FESS) was performed without surgical manipulation of the posterior maxillary sinus wall or correction of enophthalmos. Following surgery there was dramatic resolution of the osseous changes of the right posterior maxillary sinus wall. Her right enophthalmos was unchanged.

ConclusionIn this case, we demonstrated dramatic resolution of chronic maxillary atelectasis through FESS alone. Resolution of the osseous changes seen in silent sinus syndrome without manipulation of the maxillary sinus walls has not been previously reported. The most likely mechanism for this resolution is ventilation of the maxillary sinus.

Endoscopic Treatment of Silent Sinus Syndrome with Dramatic ResolutionJonathan George, MD MPH, Megan Durr, MD, Steven Pletcher, MD

University of California, San FranciscoDepartment of Otolaryngology - Head & Neck Surgery

A 28 year-old female was being followed for mild chronic sinusitis at the Department of Otolaryngology-Head & Neck Surgery at the University of California, San Francisco. She complained of pressure and pain referable to her right maxillary sinus. She had also noticed her right eye sinking with an associated pressure sensation. Physical examination demonstrated right-sided enophthalmos and mild hypoglobus. Visual acuity was grossly normal. CT and MRI demonstrated right maxillary opacification as well as bilateral mucosal thickening of the ethmoid sinuses. The orbital floor and posterior maxillary wall were deformed with resultant ipsilateral enophthalmos.

Functional endoscopic sinus surgery (FESS) for her chronic sinusitis and silent sinus syndrome was performed. Intraoperatively, she was noted to have thick mucus filling the right maxillary sinus as well as inferior displacement of the orbital floor and anterior displacement of the posterior maxillary wall. There was also rarefaction of the bone of the orbital floor. A right uncinectomy and maxillary antrostomy was performed and purulent debris was encountered and removed. The patient also underwent bilateral ethmoidectomies and a left frontal sinusotomy. The posterior maxillary sinus wall was not surgically manipulated.

The patient did well following surgery and reported improved sinus aeration and significantly reduced symptoms. Sinonasal endoscopy performed at her routine follow-up visit demonstrated a widely patent right maxillary sinus and a persistent inward bulge of the posterior wall of the right maxillary sinus. Similar endoscopy at her six-month visit demonstrated again a widely patent maxillary sinus but a resolution of the posterior wall bowing. Routine post-operative CT imaging obtained six months followingsurgery showed normal aeration of the right maxillary sinus and confirmed the dramatic resolution of the osseous changes of the right posterior maxillary sinus wall.

DiscussionIn this article, silent sinus syndrome developed in a young woman followed for chronic sinusitis. Spontaneous enophthalmos developed in the setting of an obstructed sinus outflow tract, and was associated with orbital pressure and pain. The patient was taken to the operating room for FESS. The remarkable component of her post-operative course is the resolution of the bony involution of the posterior wall of the maxillary sinus, which resolved after about six months post-operatively. She was found on post-operative CT scan to have fully restored maxillary sinus architecture. We conclude that the atelectasia of the bony sinus walls resolved spontaneously through aeration from maxillary sinus decompression alone. Specifically, resolution of the posterior maxillary sinus wall inbowing has not been reported. Thus, the osseous changes of SSS can spontaneously resolve after FESS-induced aeration alone and without direct manipulation.

These findings call into question the necessity for routine orbital floor reconstruction in these patients, which is current standard practice in the setting of enophthalmos. Several authors have indeed noted resolution of the inferior bowing of the orbital floor through FESS alone and without reconstructive manipulation of the orbital floor. Habibi et al reported on a 16 year-old girl with facial asymmetry due to left enophthalmos.13 CT revealed left maxillary sinus atelectasis with an opacified left maxillary antrum. The patient underwent FESS. Six-month and 2-year follow-ups after surgical treatment revealed aeration of the maxillary sinus and resolution of the enophthalmos. Babinski et al also reported 3 cases of SSS whose enophthalmos was completely resolved without orbital floor repair.14

In this case, the maxillary sinus wall changes resolved after FESS, with notable resolution of the prior inbowing of the posterior sinus wall. It remains to be seen if the patient’s enophthalmos will resolve, and she is being followed clinical for this. She will elect for reconstructive repair if it does not resolve.

This case highlights the spontaneous resolution of the bony changes seen in chronic maxillary atelectasis –especially the resolution of the posterior maxillary sinus – through FESS-induced aeration of the sinus alone. This calls into question the need for reconstructive repair of the orbital floor.

Enophthalmos due to maxillary atelectasis, a condition also referred to as chronic maxillary atelectasis (CMA) or silent sinus syndrome, is a rare clinical entity seen by both otolaryngologists and ophthalmologists.1,2 This syndrome is characterized by enophthalmos and hypoglobus due to gradual but progressive collapse of the orbital floor and maxillary sinus walls. Montgomery first described silent sinus syndrome in 1964.1Since then, several authors have proposed that the inciting cause of silent sinus syndrome is hypoventilation of the maxillary sinus due to obstruction of the ostiomeatal complex.3-5 This hypoventilation results in a negative pressure gradient within the sinus that produces accumulated secretions and chronic inflammation. This negative pressure gradient results in maxillary atelectasis and sinus wall collapse.6

Clinically, silent sinus syndrome is characterized by painless facial asymmetry and unilateral enophthalmos and hypoglobus. Vision and ocular movements are unaffected, and sinus pain and pressure may or may not be present. The onset of symptoms is usually gradual and progressive, but can be rapidly progressive due to sudden collapse of the orbital floor. The diagnosis is suggested by clinical findings on ocular measurements and endoscopic sinonasal examination. These may include edema and closure of the ipsilateral maxillary sinus ostium. Clinical diagnosis is confirmed on the basis of computed tomography (CT),8 which effectively evaluates the bony changes of the sinus and orbit. Common findings on CT include unilateral opacification of the maxillary sinus with associated air-fluid levels and mucosal thickening,9-11 along with obstruction of the maxillary sinus ostium.9,10 Atelectatic modulation of the maxillary sinus walls with reduction of maxillary sinus volume is seen, accompanied by inbowing and bony resorption of the orbital floor and consequent increase in orbital volume.9 Complete absence of the orbital floor has been seen with prolapse of the orbital contents into the maxillary sinus.12,13 The posterior maxillary sinus wall is also anteriorly displaced.14

Treatment involves decompression of the maxillary sinus and reestablishment of a functional drainage passage through its ostium, as well as restoring the orbital architecture through plastic reconstructive surgery. Functional endoscopic sinus surgery (FESS) is used to remove the uncinate process and open the maxillary sinus ostium in order to aerate the sinus.15 Orbital floor reconstruction is then performed for patients with diplopia or severe cosmetic deformity. In performing FESS on patients with silent sinus syndrome, great care must be taken to avoid the globe, which is in a lower position due to inferior bowing of the orbital floor. Disease progression is arrested after FESS alone, without development of further deformity. In this article, silent sinus syndrome is described in a young woman complaining of right maxillary sinus pressure who was found to have chronic sinusitis, chronic right maxillary atelectasis and ipsilateral enophthalmos. We highlight the dramatic, spontaneous resolution of the bony changes in the maxillary sinus through FESS-induced aeration of the sinus alone.

INTRODUCTION

1. Montgomery WW. Mucocele of the maxillary sinus causing enophthalmos. Eye Ear Nose Throat Mon 1964;43:41-44.

2. Virgin F, Ling FT, Kountakis SE. Radiology and endoscopic findings of silent maxillary sinus atelectasis and enophthalmos. Am J Otolaryngol 2008;29:167-170.

3. Scharf KE, Lawson W, Shapiro HM, et al, Pressure measurements in normal and occluded rabbit maxillary sinus. Laryngoscope 1995;1-5:570-574.

4. Numa WA, Desai U, Gold DR, et al. Silent sinus syndrome: a case presentation and comprehensive review of all 84 reported cases. Ann Otol Rhinol Laryngol 2005;114:688-694.

5. Thomas RD, Graham SM, Carter KD, et al. Management of the orbital floor in silent sinus syndrome. Am J Rhinol 2003;17:97-100.

6. Annino DJ Jr, Goguen LA. Silent sinus syndrome. Curr Opin Otolaryngol Head Neck Surg2008;16:22-25.

7. Bossolesi P, Autelitano L, Brusati R, et al. The silent sinus syndromeL diagnosis and surgical treatment. Rhinology 2008;46:308-316.

8. Rose GE, Sandy C, Hallberg L, et al. Clinical and radiologic characteristics of the imploding antrum, or “silent sinus”, syndrome. Ophthalmology 2003;110:811-818.

9. Illner A, Davidson HC, Harnsberger HR, et al. The silent sinus syndrome: clinical and radiographic findings. AJR Am J Roentgenol 2002;178:503-506.

10. Beasley NJ, Jones NS, Downes RN. Enophthalmos secondary to maxillary sinus disease: single-stage operative management. J Laryngol Otol 1995;109:868-870.

11. Soparkar CN, Patrinely JR, Davidson JK. Silent sinus syndrome: new perspective? Ophthalmology 2004;111:414-415.

12. Monos T, Levy J, Lifshitz T, et al The silent sinus syndrome. Isr Med Assoc J 2005;7:333-335.

13. Habibi A, Sedaghat MR, Habibi M, et al. Silent sinus syndrome: report of a case. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105:e32-e35.

14. Babinski D, Skorek A, Stankiewicz C. Chronic maxillary atelectasis (silent sinus syndrome). Otolaryngol Pol 2006;60:929-933.

CONCLUSIONS

DISCUSSIONCASE PRESENTATION

REFERENCES

Figure 1. CT scan showing Inbowing of the R posterior maxillary sinus wall.

Figure 2 PreOp MRI showing Inbowing of the R posterior maxillary sinus wall.

ABSTRACT

Jonathan R. George, MD, MPHUniversity of California- San FranciscoOtolaryngology-Head & Neck SurgeryEmail: jgeorge@ohns.ucsf.eduPhone: 415-254-5403Website: ohns.ucsf.edu

CONTACT Figure 3. Post-FESS CT scan showing resolved maxillary sinus wall deformity

Figure 4. Post-FESS CT scan showing resolved maxillary sinus wall deformity