Effects of Surgery on Mucosal Pathologic Changes following Experimental Sinusitis in Rabbit

Abstract

In the present investigation, the regenerative capacity of the infected maxillary sinus mucosa following surgical procedures was studied in a rabbit model. Sinusitis was induced by occluding the ostium with and without the addition of Staphylococcus aureus or Bacteroides fragilis, or by provoking a prolonged bacterial infection with both pathogens. The surgical procedures performed were 1) widening of the natural sinus ostium (middle meatal antrostomy; MMA) and 2) removal of sinus mucosa without ostial interference (modified radical operation; MRO). The histologic features of the entire nose-sinus complex were studied, graded semiquantitatively, and compared with findings in untreated sinusitis, or after surgery only. Whereas MMA and MRO both led to a decrease of the inflammatory features of the sinus mucosa in induced sinusitis, persistent local histopathology was observed in the ostial region following MMA surgery. This indicates the importance of local pathologic changes resulting from interactions of bacterial colonization, inflammation, and surgery in chronic sinusitis.

Serial cytokine levels during wound healing in rabbit maxillary sinus mucosa

“…They concluded that the mucosa is re-epithelialized within 2 weeks, but the regeneration of the lamina propria is incomplete, and reactive cellular processes such as bone remodeling, fibroblast proliferation, and formation of polyps are characteristic of regenerating mucosa. In another study, they investigated the wound healing of the infected maxillary sinus mucosa following surgical procedures in a rabbit model, and they concluded that persistent local histopathologic changes, such as more inflammation cells, fibrosis, and bone reaction, are abundant in the ostial region following middle meatal antrostomy, irrespective of whether there was previous infection or not [16]. Consistent with the findings of the above studies, we found that the size of neo-ostium showed a significant decrease at 4 days after injury, and regenerative mucosa had more collagen deposition in the lamina propria when compared with the normal maxillary mucosa of rabbit.…”

Microvasculature, Blood Flow, and Vasoreactivity in Rabbit Sinus Mucosa After Surgery

“… Modified radical operation (MRO) as previously described 15 . In brief, this procedure consists of complete removal of the anterior part of the sinus mucosa without interfering with the ostium, and without creating a nasoantral window (23 rabbits). Middle meatal antrostomy (MMA), which consists of widening of the ostium, both anteriorly and inferiorly, to a diameter of approximately 5 mm by removing bone and mucosa (23 rabbits). …”

“…Because clinical results of this operation have been inconsistent, 3‐7 the postoperative regenerative process in experimental animal models has been a focus of interest. In accordance with clinical experience 8,9 and experimental studies, 10‐15 it is recommended not to widen the ostium routinely, but only in cases of pathologic changes in the region. One reason for caution is the importance of ensuring an adequate blood supply to the sinuses for the healing process after surgery 12,13 .…”

Chronic Bacterial Rhinosinusitis

“…Hilding 4 pioneered the development of a rabbit model for sinusitis, which subsequently became the dominant tool with which researchers studied mucosal blood flow, lactic acid accumulation, mucosubstance histochemistry, cellular histomorphology, local and systemic humoral immune response, polyposis, and responses to a variety of thera- peutic measures. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Although the rabbit model was helpful in simulating human disease, the relative lack of experimental reagents and an inherent inability to manipulate these animals genetically have made the transition to murine research necessary. 1 To our knowledge, no mouse model for chronic bacterial rhinosinusitis exists at this time.…”