Silent Sinus Syndrome

Case reports:Case 1 A 75-year-old man presented with a history of left maxillary sinusitis, and received left radical maxillary sinusotomy fifty years ago. In September 1995 he underwent left maxillary antrostomy again because of the fang cyst of two left superior canine teeth. During that operation the orifice in his left inferior meatus performed in the former antrostomy was found obstructed. So it was reopened again. This time the patient presented to our hospital due to the symptom of diplopia for 3 years and the symptom had become worse in last 3 months. Physical examination at the time showed that his left eyeball was enophthalmos and hypoglobus. The extraocular movement was normal. The right eyesight was 0.8 and the left eyesight was 0.6. The outstanding point of the right eyeball was 16mm and of the left eyeball was 12mm. The distance between the two pupils was 98mm. The right intraocular pressure was 25mmHg, and the left intraocular pressure was 24mmHg measured by the non-contact applanation tonometer. The direct and indirect light pupillary reflexes of both eyes were normal. The pupil of the left eye was 3mm lower than the right. The optic papillae were pale and the left was more serious than the right examined by the funduscope. Nasal endoscopy demonstrated that the nasal septum deviated and protruded to left, the inferior turbinates were a little bit hypertrophy, the lateral wall of the left inferior meatus displaced laterally obviously, and the inferior meatus was broad. A coronal CT scanning of sinuses revealed that the left maxillary sinus collapsed and the bilateral ethmoid sinusitis with opacification. The clinical diagnosis was established as secondary silent sinus syndrome. Case 2 A 29-year-old woman presented with a history of discontinuity headache and feeling dryness of nasal cavity for ten years. Physical examination at the time showed that none eyeballs were enophthalmos and hypoglobus. The extraocular movement was normal. The direct and indirect light pupillary reflexes of both eyes were normal. Nasal endoscopy demonstrated that the inferior turbinates were atrophic, the lateral wall of the right inferior meatus displaced laterally obviously, and the inferior meatus was broad. A coronal CT scanning of sinuses revealed that the right maxillary sinus collapsed and the bilateral ethmoidsinusitis with opacification. The clinical diagnosis was established as secondary silent sinus syndrome. Case 3 A 28-year-old woman presented with a history of discontinuity nasal obstruction and headache for ten years. Physical examination at the time showed that none eyeballs were enophthalmos and hypoglobus. The extraocular movement was normal. The direct and indirect light pupillary reflexes of both eyes were normal. Nasal endoscopy demonstrated that the nasal cavities were filled with nasal polyps. A coronal CT scanning of sinuses revealed that the right maxillary sinus collapsed and the bilateral ethmoid sinusitis with opacification. The clinical diagnosis was established as secondary silent sinus syndrome. Case 4 A 67-year-old man presented with a history of discontinuity nasal obstruction and pus rhinorrhea for thirty years and received left radical maxillary sinusotomy twice. Physical examination at the time showed that none eyeballs were enophthalmos and hypoglobus. The extraocular movement was normal. The direct and indirect light pupillary reflexes of both eyes were normal. Nasal endoscopy demonstrated that the nasal cavities were filled with nasal polyps. A coronal CTscanning of sinuses revealed that the right maxillary sinus collapsed and the bilateral ethmoid sinusitis with opacification. The clinical diagnosis was established as secondary silent sinus syndrome. Etiology Silent sinus syndrome (SSS) is a complex of symptoms that is characterized by spontaneous and progressive unilateral enophthalmos. SSS has two types. One is Primary Silent Sinus Syndrome (PSSS). The other is Secondary Silent Sinus Syndrome(SSSS). The main differents of the two types are histories and symptoms. The patients with PSSS have no histories of trauma, surgery and tumor. And the patients also have no obvious symptoms of rhinitis or sinusitis. CT scanning demonstrated the ill maxillary sinus atelectasis is helpful to the clinical diagnosis. A well ventilated maxillary sinus performed by the operation has good therapy effect and prognosis. In 1964, Montgometry described the first case of patient whose enophthalmos was caused by mucocele of the maxillary sinus. The otolaryngologists soon took more and more notice of this syndrome. And by June 2000, a total of 45 cases had been reported. The SSS patients had no history ofsinus deformity, trauma, operation or tumor before the symptom appeared. Generally they had no obvious symptom of nasal or sinus disease. The age at present ranges from 26 to 74 years old, with a mean of 40.3 years old. No differences are found between the two sides of sinus. No relationships are found between SSS and gender, profession, smoking, drinking or heredity etc. The exact reason is unknown. There are four main theories regarding the pathogenesis. The first is the theory of negative pressure. The obstruction of the ostium of the ostiomeatal complex (OMC) results in hypoventilation of the maxillary sinus. And the ostium is occluded by inspissated mucous. The medial infundibular wall or middle turbinate lateralizes in the pathological surroundings. Mucocele or nasal polyps obstruct the antrum or ostium. Inflamed mucosa in the presence or absence of rhinosinusitis obstructs the ostium. Hypoplastic maxillary sinus and antrum leading to decrease ostium diameter result in more frequent occlusion. The presence of infraorbital ethmoid (Haller cells) makes the maxillary ostium narrow. All these make the maxillary sinus hypoventilation and negative pressure within the sinus. Thechronic negative pressure arouses osteopenia and bone remodeling. Finally the maxillary sinus atelectasis is made. Some scholars think that this mechanism is similar to the retraction and atelectasis that occur in the middle ear space with chronic eustachian tube obstruction. Animal test has proved that the slight, persisting pressure will cause significant metabolic and structural changes in the bony walls of craniofacial cavities. Scarf and his colleagues examined rabbit maxillary sinuses in which the ostium was occluded and a serial of pressures were recorded. Their study demonstrates a transient increase in maxillary pressure (11.8mmHg over 4-12 min) followed by a negative pressure deflection and equilibrium at -28.4 mmHg at 20-50 min. This differential is attributed to the more rapid influx of carbon dioxide from the mucosal blood into the sinus cavity driven by the large carbon dioxide partial pressure gradient. The gradient equilibrates rapidly because of the solubility of carbon dioxide in body tissues. The subsequent development of negative sinus pressure may result from the absorption of sinus gasses into the sinus mucosa, which follows the subatmospheric pressure gradient within the mucosa. Andsome scholars have found the negative pressure has same function in human's maxillary sinus. The second theory is inflammatory erosion, which suggests that chronic inflammatory diseases would induce the erosion of the orbital floors. Some scholars regard that the negative pressure in maxillary sinus together with the chronic inflammatory result in the SSS. Antonelli and his colleagues suggest that subclinical inflammatory mediating osteopenia results in the maxillary bone loss, and the negative pressure in the maxillary sinus also takes part in the mechanisms. Davidson's medical group has reported an asymptomatic patient whose maxillary sinus had negative pressure. They suggest that an otherwise healthy person whose hypoventilated maxillary sinus has chronic negative pressure has no symptom. In fact, Dr. Kass has noticed that the advancing stage of enophthalmos and bony deformity is negatively correlated to symptoms associated with the patient's disease. At the same time, advancing stage of enophthalmos is correlated to the smaller atmospheric changes which steps to negative pressure within the sinus. Some scholars have reported that changes of pathology inthe ethmoid sinus may have some functions during the advancing stage of the disease. The third is hypoplasia theory. It is postulated that SSS is the result of infection in the congenital hypoplasia maxillary sinus. But someone has reported a case of SSS whose bilateral maxillary sinuses symmetry, well developed and ventilated showed by the CT scanning six years ago. The fourth is calcium absence theory. We postulated that patients with calcium ansence, especially the crowd such as pregnant women and the aged, were susceptible to SSS. Clinical characers The SSS often occurs in unilateral maxillary sinus, which is characterized by enophthalmos without difficulties of eyeball movement and vision disorders. The intraocular pressure is normal. The enophthalmos is spontaneous and progressive without any other symptoms. The patients with PSSS have no histories of trauma, surgery and tumor. And the patients also have no obvious symptoms of rhinitis or sinusitis. The patients with SSSS may have histories of trauma, surgery and tumor or have symptoms of rhinitis or sinusitis. Only a small part of patients have numbness sensation or slight pain of the check. The range of enophthalmos varies from 2mm to 6mm, witha mean of 2.9mm, and hypoophthalmos can vary from 3 mm to 6mm, with a mean of 3.6mm. Someone has reported a case of patient whose left eye is 8mm lower with temporary transient diplopia. The obstruction of the ostiomeatal complex caused by nasal septum deviation, middle turbinate lateralization or uncinate process hypertrophy or lateralization is revealed by the nasal endoscopy. The presenting symptom of the SSS is spontaneous enophthalmos that occurs in weeks, months or several years. Most commonly the patients present to an ophthalmologist for evaluation of asymmetry of their eyes, which may be interpreted as exophthalmos of the contralateral eye, ptosis of the affected eye, or enophthalmos of unknown etiology. When a work-up for the more common causes of enophthalmos rules out metabolic, ocular or neurological etiology, the evaluation will focus on the anatomy finally. This leads to an orbital and sinus computed tomography scan, which will demonstrate unilateral maxillary sinus opacification and collapse with the orbital floor displacement inwards. In some cases the maxillary sinus even vanishes. Clinical diagnosis The patient with PSSShas its'characters in history, clinical manifestation and CT scan. It should be considered seriously if the enophthalmos was spontaneous and progressive with no other symptoms. The patients usually have no disorders of eyeball movement and eyesight. The intraocular pressure is often normal. There is no documented congenital deformity or significant anatomic abnormality of the sinus or nasal cavity. There is no history of orbital trauma. And there is no history of enophthalmos caused by other etiology. There is no significant complaints related to the nose and sinus disorders, specifically no episode of acute rhinosinusitis in the previous 6 months, and neither no history of chronic rhinosinusitis. The patients with SSSS may have histories of trauma, surgery and tumor or have symptoms of rhinitis or sinusitis. Spontaneous enophthalmos is caused by remodeling and inferior bowing of the osteoporosis maxillary roof or orbital floor, as demonstrated on a coronal sinus CT scan. The diagnosis would be established on the basis of the symptoms, signs, related history and the results of the CT scan. Treatment and prognosis The effective treatment of the silent sinus syndrome is operation . The...