# Characterization of Pterygomaxillary Suture Morphology: A CBCT Study
###### Abstract  
One of the most challenging procedures during maxillary osteotomy is pterygomaxillary suture (PMS) separation, due to the difficulty of directly inspecting this suture and the anatomical complexity of the adjacent structures. Knowing the precise anatomical dimensions and the position of the PMS, namely, the angle at which to approach this structure, may help in determining the proper osteotome. It will also help the oral and maxillofacial surgeon to perform this sensitive procedure more precisely and to minimize surgical complications (e.g., internal maxillary artery injury and unfavorable fracture during separation). The current study aimed to evaluate the morphology of PMS in an adult Israeli population using CBCT scans of the maxilla. Fifty CBCTs of healthy males (n = 27) and females (n = 23) were collected and analyzed. The vertical height, maximal thickness, and angulation of the PMS relative to the midsagittal plane of the skull were evaluated on both the right and left sides of the patient. An independent samples _t_-test was carried out to determine PMS morphological differences between males and females. A related samples _t_-test was conducted to determine the PMS morphological differences between the right and left sides. No significant differences in PMS parameters were found between sides in males and females (_p_ > 0.225). Both males and females exhibited similar height and angulation of the PMS (_p_ > 0.486). Interestingly, the PMS thickness was statistically greater in males (_p_ = 0.029); however, this difference was clinically insignificant. The mean dimensions of the PMS in a healthy Israeli adult population are presented and discussed, as well as the clinical and methodological implications. p _Applied_  
_sciences_  
20 February 202314 March 202314 March 202315 March 202314 March 2 fissure includes the opening of the pterygopalatine fossa, which contains many important neuro-vascular structures and constitutes an important central junction between the nasal and oral cavities, the orbit, the infratemporal fossa, and the nasopharynx [4; 5; 6]. The PMS is separated using a designated angulated osteetome, because it is performed in a \"blind\" indirect fashion. The main challenge while separating the PMS is to find its position from the lateral aspect. This is usually done by identifying the convexity in the pterygomaxillary fissure using a curved osteetome. Some patients have less clear and defined anatomy, which makes it difficult to identify the precise location of the separation [7; 8]. PMS separation is the final stage of maxillary release from the base of skull during Le Fort I osteotomy [9] (Figure 2). The main reason that the PMS is separated last during maxillary osteotomy is its proximity to the pterygoid plexus vein and the maxillary artery [7; 10; 11; 12]. Thus, if blood vessel damage occurs during osteotomy, the surgeon can directly locate the bleeding vessels and treat them. The most vulnerable source for significant bleeding during surgery is the internal maxillary artery and its branches, especially the descending palatine artery [3; 4; 9; 10; 11]; however, the pterygoid plexus can also be a significant cause of venous bleeding [11]. After arterial damage, there may be impaired maxillary perfusion, followed by loss of teeth, gingival necrosis, periodontal vulnerability, or even complete necrosis and loss of the dento-alveolar segment [10; 13]. An additional complication that can occur as a result of PMS separation is an unfavorable bone fracture [14; 15]. Several studies reported [6; 11; 15] that using excessive force while performing PMS separation resulted in unfavorable fractures of the sphenoid bone or other bones of the cranial base, which sometimes resulted in cranial nerve damage. Previously, three types of fractures were observed during PMS separation: (a) a fracture line in the desired plane, (b) a fracture line passing through the posterior wall of the maxillary sinus, and (c) a fracture line passing through the upper part of the pterygoid bone.