Classification of orbital complications of sinusitis

Introduction: Classification of orbital complications of sinusitis will help otolaryngologist in devising effective treatment modalities. Any classification system devised will have to take into consideration the anatomy of the orbit and the mechanism causing it. Hubert was the first person to embark on classifying these complications. He studied clinical data from about 114 patients during preantibiotic era. He based his classification on the anatomy of orbit, perceived progression of infection, responsiveness to treatment and general prognosis. Chandler fine tuned this classification system and made it more acceptable.

Chandler’s classification system:

Chandler grouped his patients under 5 heads:

1. Group I – Preseptal cellulitis
2. Group II – Orbital cellulitis
3. Group III – Subperiosteal abscess
4. Group IV – Orbital abscess
5. Group V – Cavernous sinus thrombosis

Group I (Preseptal cellulitis): This is actually inflammatory oedema anterior to orbital septum causing the eyelids to swell. This condition is caused due to restricted venous drainage. The eyelids though swollen are not tender. Since the inflammation doesn’t involve postseptal structures there is no chemosis, Extraocular muscle movement limitations and vision impairment. Proptosis may be present to a mild degree.

Group II: Orbital cellulitis causes pronounced oedema and inflammation of orbital contents without abscess formation. It is imperative to look for signs of proptosis and reduced ocular mobility as these are reliable signs of orbital cellulitis. Chemosis is usually present in this group. Loss of vision is very rare in this group, but vision should be constantly monitored.

Group III: In this group abscess develops in the space between the bone and periosteum. Orbital contents may be displaced in an inferolateral direction due to the mass effect of accumulating pus. Chemosis and proptosis are usually present. Decreased ocular mobility and loss of vision is rare in this group.

Group IV: Orbital abscess usually involves collection of purulent material within the orbital contents. This could be caused due to relentless progression of orbital cellulitis or rupture of orbital abscess. Severe proptosis, complete ophthalmoplegia, and loss of vision are commonly seen in this group of patients.

Group V: Cavernous sinus thrombosis – Development of bilateral ocular signs is the classic feature of patients belonging to this group. These patients classically manifest with fever, headache, photophobia, proptosis, ophthalmoplegia and loss of vision. Cranial nerve palsies involving III, IV, V1, V2 and VI are common.

Schramm’s modification of Chandler’s classification:

Schramm after studying his patients classified those patients with preseptal cellulitis with chemosis as a separate entity. Prognostically he placed these patients between Chandler’s group I and group III patients. Schramm considered these patients as a separate entity as they did not consistently improve with antibiotics and surgery needs to be advocated.

Moloney’s modification of Chandler’s classification:

Moloney modified Chandler’s classification by according lower priority to preseptal orbital infections. In a nutshell he divided orbital complications into preseptal and postseptal complications.

Signs indicating postseptal complications are:

1. Proptosis
2. Gaze restriction
3. Decreased visual acuity
4. Color vision defects
5. Afferent pupillary defect