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Experimental myospherulosis of the paranasal sinuses: a histologic rabbit study
W T Culviner1, D W Leonard, C L Wilhelmsen
1Department of Otolaryngology, National Naval Medical Center, Bethesda, Maryland, USA.
Abstract:
Myospherulosis or lipogranuloma formation is frequently iatrogenic and is caused by a petrolatum, lanolin, or paraffin-based ointment becoming trapped within tissue. Four different ointments, including the newly available Bactroban nasal, were studied in a rabbit paranasal sinus model to evaluate their proclivity to induce myospherulosis. The maxillary sinuses of 16 New Zealand white rabbits were bilaterally inoculated with Bactroban, Bactroban nasal, tetracycline, or bacitracin ointments and compared to saline controls in two rabbits. Sinus specimens were harvested at 2 and 4-week intervals and processed for histologic study. Myospherulosis formation was uniformly induced with the Bactroban nasal, bacitracin, and tetracycline ointments in 8/8, 7/8, and 8/8 sinuses, respectively. In contrast, myospherulosis was not induced in the 5/8 of the sinuses using Bactroban. The data from this investigation indicate that Bactroban nasal (paraffin vehicle) is similar to bacitracin and tetracycline ointments (petrolatum and petrolatum-lanolin vehicles) in that they all can cause myospherulosis. In contrast, Bactroban (a water-soluble, polyethylene glycol base) causes myospherulosis to a much smaller extent. Our results emphasize the differences between the two types of Bactroban preparations and provide objective data that can be evaluated by otolaryngologists who apply these ointments following nasal cavity surgery.
Insights
Ointments containing petrolatum, lanolin, or paraffin can cause iatrogenic myospherulosis (lipogranuloma). Bactroban nasal, bacitracin, and tetracycline ointments induced myospherulosis in rabbits, unlike water-soluble Bactroban.
Area of Science:
- Otolaryngology
- Surgical Pathology
- Dermatology
Background:
- Myospherulosis, or lipogranuloma, is an iatrogenic condition often caused by trapped ointments.
- Commonly implicated ointment bases include petrolatum, lanolin, and paraffin.
Purpose of the Study:
- To evaluate the myospherulosis-inducing potential of four different ointments in a rabbit paranasal sinus model.
- To compare Bactroban nasal with other commonly used antibiotic ointments and a water-soluble alternative.
Main Methods:
- 16 New Zealand white rabbits underwent bilateral maxillary sinus inoculation with Bactroban, Bactroban nasal, tetracycline, or bacitracin ointments.
- Saline controls were used in two rabbits.
- Sinus specimens were harvested at 2 and 4 weeks for histologic examination.
Main Results:
- Myospherulosis was uniformly induced by Bactroban nasal (paraffin vehicle), bacitracin (petrolatum vehicle), and tetracycline (petrolatum/lanolin vehicle) ointments.
- Bactroban (polyethylene glycol base) showed a significantly lower incidence of myospherulosis induction.
- Histologic study confirmed myospherulosis formation in 8/8, 7/8, and 8/8 sinuses for Bactroban nasal, bacitracin, and tetracycline, respectively.
Conclusions:
- Bactroban nasal, bacitracin, and tetracycline ointments possess a proclivity to induce myospherulosis due to their base composition.
- Bactroban, with its water-soluble polyethylene glycol base, is less likely to cause myospherulosis.
- These findings highlight the importance of ointment vehicle selection in preventing iatrogenic complications in otolaryngologic surgery.
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