The use of piezoelectric instrumentation has been investigated to perform an endoscopic-assisted transpterygoid maxillectomy for a maxillary ameloblastoma. This technology allowed safe disinsertion of the pterygoid root from the cranial base through a precise and clean osteotomy, while minimizing the risk of inadvertent soft-tissue injury. Piezoelectric saws can represent an alternative to high-speed endoscopic drills in selected cases. For posterior maxillary neoplasms, we recommend the employment of endoscopic-assisted maxillectomy, as it offers improved anatomical exposure and a more accurate control of tumor margins. Ameloblastoma is an odontogenic tumor with locally invasive behavior that frequently arise from the mandible. Maxillary ameloblastomas are relatively rare compared to mandibular lesions and present specific surgical challenges due to the proximity of the maxillary sinus, masticatory space and orbital cavity. Surgery is the gold-standard treatment, and achieving clear margins is essential to reduce recurrence (reported to occur up to 7 years after treatment) 1 and to prevent extension into surgically challenging regions. While most mandibular ameloblastomas are treated via a transoral approach, a transnasal endoscopic corridor offers clear advantages for posterior maxillary lesions involving the maxillary sinus and pterygoid plates. Indeed, endoscopic-assisted maxillectomies performed via a trans-pterygoid route benefit from the optimal visualization of the maxillary box and the retro-maxillary spaces, ensuring oncological radicality with reduced morbidity 2. The cornerstone of this approach is the endoscopic dissection of the pterygoid root and its detachment from the cranial base. This is usually performed with chisels or powered instrumentations such as endoscopic high-speed drills, with the risk to perform imprecise osteotomies or inadvertently damage adjacent structures. Piezoelectric instrumentations, conversely, are specifically designed to selectively cut bone while sparing other tissues. These devices operate based on the piezoelectric effect, whereby an electric current passing through ceramic material induces cyclical contraction and expansion. The resulting vibrations are amplified and transmitted to the instrument tip, producing a mechanical cutting action that selectively affects mineralized tissues. In this way, piezoelectric saws allow precise osteotomies, avoiding potential harm if the cutting tip encounters delicate structures such as nasal mucosa, pterygopalatine fossa or pterygoid muscles. In this paper, we propose a novel application of ultrasonic piezoelectric instrumentation to perform an endoscopic assisted transpterygoid maxillectomy for a posterior maxillary ameloblastoma involving the pterygoid region. We report the case of a 60-year-old male patient incidentally diagnosed with a keratinizing ameloblastoma involving the right maxillary sinus and the pterygoid plates (Figures 1 and 2). A combined trans-oral and endoscopic transpterygoid surgical approach (Video 1) was employed, using Piezosurgery (Mectron, Carasco, Italy) as the main cutting instrument. The procedure was performed under general anesthesia with orotracheal intubation. The patient was placed in a supine position with slight flexion of the head. The trans-nasal approach was performed via a right paraseptal corridor using a 0° rigid endoscope. First, an endoscopic medial maxillectomy posterior to the nasolacrimal duct was performed, increasing maxillary sinus workspace through an expanded medial antrostomy, partial uncinectomy, and partial resection of the inferior and middle turbinates. After cauterization of the sphenopalatine artery at the sphenopalatine foramen, the posterior wall of the maxillary sinus was removed to address the nasal extension of the lesion at the maxillary floor. Afterwards, the incision of the posterior maxillary periosteum allowed access to the pterygopalatine fossa, which was gently dissected to identify the internal maxillary artery (IMA). This latter and its main terminal branches were ligated (Figure 3). The neural structures within the pterygopalatine fossa were preserved and displaced laterally to expose the pterygoid root and the two pterygoid plates. Pterygoid root osteotomy was then performed in an anteroposterior direction using Piezosurgery, completing the detachment of the lesion from the cranial base (Figure 4). In Figure 5, employing a 45° scope, the relationship between the pterygoid root, the maxillary floor and the lesion is visible. Finally, the tumor was removed en-bloc via a transoral vestibular approach through piezoelectric osteotomies, maintaining macroscopically tumor-free margins of approximately 1 cm. Reconstruction was performed using a Bichat's fat pad flap and obturator placement, in accordance with the patient's preferences. The procedure was completed in a total operative time of 150 min. No intraoperative complications were observed. The histopathologic report confirmed the diagnosis of keratinizing ameloblastoma, infiltrating the lateral pterygoid plate, with negative surgical margins. No postoperative complications occurred, and the patient was discharged on an oral diet after 3 days. Follow-up endoscopic medications at 10, 20, and 30 postoperative days demonstrated complete healing of the surgical field, with no bone exposure or granulation tissue. Endoscopic-assisted maxillectomies, first classified by Deganello et al. on the basis of the depth of the posterior resection margin (type 1: pterygopalatine fossa; type 2: pterygoid root; type 3: Eustachian tube) 2, ensure clear advantages over traditional open techniques. The endoscopic approach provides optimal control of the retro-maxillary spaces, allowing to safely disinsert the pterygoid root from the skull base while preventing intraoperative bleeding from the internal maxillary artery and pterygoid plexus. Moreover, the endoscopic evaluation of the posterior resection margin ensures the control of potential neoplastic escape routes (i.e., soft tissue of the infratemporal fossa, neurovascular bundles of the pterygopalatine fossa) and reduce the rate of deep positive margins 3. This consideration is particularly relevant for maxillary ameloblastomas, which often display more aggressive biological behavior than mandibular lesions, with a greater tendency for extraosseous extension and infiltration of adjacent soft tissues. Consequently, the sole enucleation is associated with a substantial risk of positive margins and higher local recurrence rates, potentially necessitating additional surgical procedures or adjuvant radiotherapy 4. In this report, we describe a type 2 endoscopic-assisted maxillectomy performed with Piezosurgery to detach the pterygoid root from the skull base. Piezoelectric instrumentation has already been studied in endoscopic surgery as a substitute of high-speed drill 5, but to the best of our knowledge, this is the first description of the use of such technology in endoscopic-assisted transpterygoid maxillectomies. The employment of Piezosurgery allowed us to safely perform the pterygoid osteotomy, avoiding any damage to surrounding soft tissues. Compared with high-speed drills, it generates significantly less bone dust, resulting in a cleaner surgical field and allowing more precise bone cut. We found this aspect particularly relevant during the pterygoid osteotomy, as the use of endoscopic burrs carries a risk of inadvertent injury to the pterygopalatine and pterygoid fossa, potentially leading to bleeding from the IMA or the pterygoid plexus. Moreover, employing piezoelectric devices considerably reduce the thermal bone damage which, instead, is induced by prolonged drilling. This may decrease the incidence of post-operative bone-related complications (such as osteitis or bone necrosis). On the other hand, authors should acknowledge potential limitations of Piezosurgery in this kind of surgery. First, thermal injury to the nasal vestibule may occur if the surgeon employs the instrument in the wrong way. In contrast to high-speed drills, piezoelectric devices require no applied pressure on the bone, as excessive force reduces microvibrations and transfer the instrument's energy to the handle causing overheating. Second, endoscopic burrs are still preferred when dealing with malignant histology, where tumor spread may necessitate the endoscopic dissection and clearance of neurovascular escape routes and their associated bony canals or foramina, such as the vidian canal and the foramen rotundum or ovale. This is the first application of Piezosurgery in endoscopic-assisted transpterygoid maxillectomies. This technology allowed safe disinsertion of the pterygoid root from the cranial base through a precise and clean osteotomy, while minimizing the risk of inadvertent soft-tissue injury. In selected cases, piezoelectric instrumentations can be a suitable alternative to high-speed drills for transpterygoid endoscopic approaches. In the context of insidious posterior maxillary neoplasm such as ameloblastomas, we recommend the employment of endoscopic-assisted maxillectomy as it provides wider anatomical exposure and a more precise control of tumor margins. The authors have nothing to report. The research was conducted ethically, with all study procedures being performed in accordance with the requirements of the World Medical Association's Declaration of Helsinki. The authors declare no conflicts of interest. Research data are not shared.
Ioppi et al. (Tue,) studied this question.