Investigation of the variability of the pterygomandibular space from the point of view of the target point of the inferior alveolar nerve block.

Introduction: A thorough knowledge of the anatomy and variability of the pterygomandibular space (PMS) is essential to the success of local anesthesia. This study is aimed at determining the volume of the PMS depending on the shape of the skull, face and mandible using the computed tomography (CT).

Materials And Methods: anonymized computed tomograms of 48 adult patients were analyzed, the indicators of the cranial index (CI), facial index (FI) according to Yzard, the high lengthy index of the mandible (HLI), the latitudinal-altitude index of the mandible (LAI), the longitudinal latitude index of the mandible (LLI) were calculated.

Results: Differences in the volume of the PMS were found depending on the shape of the skull, face and mandible. When determining the CI, the largest volume of space on the right was observed with brachycrania (2.05 ml), on the left - with mesocrania and brachycrania (2.0 ml each). With regard to the FI, the largest volume of space was obtained with medium face on the right side (2.03 ml) and broad and medium types of faces (2.0 ml each) on the left. When calculating the indicators for the shapes of mandible, the largest volume of space was found in the brachygenic (2.05 ml), leptogenic (1.98 ml) and platigenic (1.97 ml) shapes on the right and leptogenic and platigenic shapes on the left (2.0 ml each). There were statistically significant differences in the volume of the right side of the PMS between different shapes according to the cranial index (F = 5.075; p = 0.0095). The most pronounced difference was present between samples with brachycrania and dolichocrania: 0.35 mm³ (95% CI 0.05-0.65); p = 0.0188. There was a statistically significant correlation with sex for parameters on both the right and left sides. The values of indicators in men exceeded those of measurements obtained from women.

Conclusion: The data obtained determine the differences in the volume of the PMS in individuals with different shapes of the skull, face and mandible, as well as sex differences. Thus, indicating the need to take into account these features when choosing the required amount of anesthetic in clinical practice. The average volume of the PMS space, according to our data, is 1.8-2.0 ml, which is consistent with the clinical data described in the literature.