The goals of cystic lesion treatment are to eliminate the possibility of a recurrence and to minimize surgical morbidity. If the lesion is large or difficult to access, the conventional method of cyst enucleation can be invasive. Resnick et al. have reported that minimally invasive approaches in the oral and maxillofacial region may become the standard [4]. These techniques have been shown to reduce bleeding and swelling, minimize scarring, provide superior visualization, create less tension on vital structures, increase stability, and reduce hospital length of stay and recovery time [4]. Huang et al. also reported endoscope surgery reduces blood loss compared to the conventional method [5]. Support of the bone under the flap is required for better soft tissue healing; thus, in conventional methods, large flaps are needed to completely contain cysts; however, by using endoscope, the flap size can be drastically reduced. Also, a small bony hole makes the flaps and bones more stable, which reduces swelling. This can decrease bleeding and postoperative edema. Additionally, in cases requiring extensive incision due to a difficult or extraoral approach, complications, such as damage to the facial nerve and scarring of the skin by the endoscope, can be avoided [6].
Using an endoscope for cyst enucleation is one type of minimally invasive approach. Endoscope-assisted operations have been performed for many years in many fields of general surgery, otolaryngology, obstetrics, gynecology, and so on. Recent advances in imaging, fiber optic technology, and instrumentation may lead to further advancement of endoscopic approach surgery [7]. Kretzschmar et al. reported the intraoral endoscopic enucleation of a solitary mandibular bone cyst, underlining the fact that easy access to the mandibular condyle with good visibility allows for definitive treatment of central lesions of the condyle [8]. Mohamed et al. reported that approaching the maxillary sinus with a sub-labial view by using endoscopic has merits for direct approach. This advantage is not available in conventional nasal approaches due to angulation of nasal passage [9].
With conventional methods, visualization of the operative field is often difficult when approaching the maxillary or mandibular posterior areas. In poor visualization of the operative field, residuals are often left in the teeth area or blind spots. Endoscope-assisted cyst enucleation enables superior visualization of the operative field by magnifying the view through the lens. It provides good illumination, clear visualization of the operation field, and, as a result, more accurate surgery is possible [6, 10]. The scope allows the entire cystic lesion to be seen clearly with angled instruments [11]. Incomplete removal of cystic lesions leads to recurrence [12]. On the other hand, by using the endoscope, it is possible to remove the cystic cavity, eliminating epithelial remnants within the bone or behind the roots of the tooth, using direct vision and curved cutting tools and drills [11, 13]. So, we can reduce the size of the bony hole because we can obtain good visualization of the right down area of the bone wall and increase the possibility of bone formation inside the cyst area by maintaining the space of the outer wall. When the endoscope was used in most of the operations, it was easy to identify the mandibular notch, lingula, mandibular angle, and maxillary sinus, which reduced recurrence. Also, by digitally observing the operation field on a monitor, it was possible to teach the technique and record the operation [14].
Endoscope-assisted surgery requires basic endoscopic equipment and special instruments. The instruments must be modified and minimized for this technique. The endoscope can be mounted on the retractor used to maintain the optical cavity. Also, one can use a drill or irrigation syringe mounted on the endoscope to make a small bony window. The commonly used rigid nasal endoscope is too long and bulky for dento-alveolar surgery and makes it difficult to achieve the necessary field angle during apicoectomy and retrograde filling of a posterior mandibular tooth. In such circumstances, a good surgical view can be obtained using the 30° or 70° angled endoscope. The arthroscope that is used for TMJ surgery is also a suitable size for cyst enucleation and is easy to handle. The visual field obtained with an arthroscope, however, is small, and the illumination is grainy. Beltran et al. classified endoscopes by the size of the surgical field [15]. There are several types of endoscopes: a direct endoscope is a rigid rod lens endoscope that is introduced directly into a cavity to visualize the surgical field. Immersion endoscope is used to perform surgery in cavities that are not accessible with simple inspection due to contamination. When the endoscope is used in a support sheath, the assembly is called support endoscope [16]. They claimed that a support endoscope (SE) allowed visualization of a 4- to 7-mm surgical field while an immersion endoscopy (IE) had a smaller observation distance of 2 to 3 mm under continuous irrigation. The choice of the appropriate endoscope and position for this technique remains a challenge. Therefore, modified, minimal, and easily operable instruments are needed for enucleating jaw cysts [15].
Endoscope-assisted surgery has a problematic aspect where both the microscope and surgical instruments need to pass through a single hole, making it difficult to operate due to limited visibility. This problem can be resolved by using multiport techniques, which creates two holes for the instrument and one hole for the microscope. This not only ensures secure manipulation of the instrument, but also the visibility [17]. Also, surgery time is reduced, and the technique is less precarious than with a single port. Therefore, a non-expert operator can achieve satisfactory results [18]. According to Huang et al., surgery time changes over time based on an operator’s proficiency. Endoscope surgery can be performed faster than traditional methods by skilled technicians, and this dual-port technique facilitates a shorter surgery [5]. The endoscope provides a magnified two-dimensional video image, so the operator needs to be skilled in specific eye-hand coordination [6]. Oral and maxillofacial surgeons who try to perform the endoscopic procedure must receive sufficient training and obtain adequate surgical experience of the relevant anatomy and understanding of the three-dimensional concept. Furthermore, operating team coordination is important in this approach. These factors help to smooth the surgical procedure and reduce operating time.
In conventional methods, a large hole must be created to completely remove the cystic wall. Guanqi et al. have reported that large burr hole defects have a higher tendency to be incompletely healed and prevent bone healing [19]. The number of walls surrounding the bone has a significant impact on bone healing, as adjacent bone walls contain both osteogenic and angiogenic cells [20]. Therefore, if a small bony hole is created, the possibility of bone healing is greater than traditional methods. Fixing a bony window again is the surest method. However, since additional plates and screws, which may need to be removed in the future, would be necessary, it would be best to use a small bony hole instead.
For good visualization of the operation area, continuous irrigation and suction are required during the procedure. Engelke et al. reported that if the endoscope was placed inside an anatomic cavity and supported by any part of the cavity wall under continuous irrigation, good visualization of intraosseous structures was obtained [21]. Nahlieli et al. also demonstrated that endoscopic visualization under continuous irrigation is essential for assessing the anatomic structure in the operative region [22].
