Fig 1.
The schema of endoscopic soft palate augmentation (ESPA).
An approximately 8-mm hole was created in the most anterior part of the soft palate using an electric knife to insert the endoscope. This hole needed because the endoscope could not insert by nasal approach in dog, due to narrowness of the canine nasal cavity. Then, the endoscope was inserted to the nasal side of the soft palate.
Fig 2.
Approximately 2-ml of the materials was injected to each of the dogs until the soft palate slightly touched the post-pharyngeal wall.
Fig 3.
The amount of nasal air leakage during inspiration at rest.
The changes of nasal air leakage during inspiration at rest (soft palate was not lifted). The amount of nasal air leakage during inspiration in each dog decreased slightly, compared to the pre-ESPA value, but the decrease was not enough to cause apnea or hypopnea. (0 = Immediately after ESPA).
Fig 4.
The amount of nasal air leakage during expiration under rebreathing.
The changes of nasal air leakage during expiration under rebreathing (soft palate was lifted due to levator veli palatini action). The amount of nasal air leakage during expiration under the rebreathing system was significantly decreased in all dogs injected with materials used for ESPA, compared with pre-ESPA (p<0.05). (0 = Immediately after ESPA).
Fig 5.
The amount of nasal air leakage during inspiration at rest.
The amount of nasal air leakage during inspiration at rest decreased in all dogs compared to the pre-ESPA value, but apnea or hypopnea was not observed. Moreover, no significant difference in the outcomes was observed among the materials.
Fig 6.
The amount of nasal air leakage during expiration under the rebreathing system.
The amount of nasal air leakage during expiration under the rebreathing system decreased significantly in all the dogs injected with any of the materials during ESPA. The median amount of nasal air leakage of the non-treated dogs (pre-ESPA: n = 10) was 0.16 L/sec, whereas at 6 months after ESPA, the median amount of nasal air leakage during expiration was 0.055, 0.089, and 0.049 L/sec in dogs injected with purified sodium hyaluronate, atelocollagen, and autogenic fat tissue, respectively.
Fig 7.
The maximum value of the soft palate thickness between the dogs injected with sodium hyaluronate, atelocollagen and non-treated dogs was the same. Fat tissues were observed around the injection site of the soft palate of the dogs injected with purified sodium hyaluronate, whereas fibrous tissues were observed in those injected with atelocollagen. In contrast, fibrous tissues and vasculatures, appearing as lymphatic or blood vessels, with minimal muscle tissues (arrow) were observed around the injection site in the dogs injected with autogenous fat. (Asterisks are levator veli palatini).
Table 1.
The thickness of the soft palate at 6 months after the endoscopic soft palate augmentation (ESPA) (mm).