Μελέτη της εφαρμογής ναρθήκων υπολογιστικής καθοδήγησης στην οδοντιατρική αναισθησία

Abstract

Background and Aim: Maxillary nerve block through the greater palatine canal (GPC) is a well-established regional anesthesia technique capable of providing profound anesthesia of the half maxilla. Despite its documented effectiveness, the clinical use of this technique remains limited due to the anatomical variability of the greater palatine canal, the technical sensitivity of freehand needle placement and the potential risk of complications related to inaccurate trajectory control. The integration of cone beam computed tomography (CBCT) with digital surgical guide 3d printing offers the possibility of converting this demanding technique into a standardized and reproducible protocol. The aim of the present thesis was to evaluate the feasibility, accuracy, anesthetic effectiveness, patient acceptance and morphometric parameters of a computer-guided maxillary nerve block technique using surgical guides. Materials and Methods: Thirty-one patients were initially enrolled in this study. Patient-specific guides were digitally designed using preoperative CBCT data combined with data from intraoral scans. Each guide incorporated a metallic sleeve and a depth-control stop to allow controlled advancement of a 27G needle through the greater palatine foramen toward the pterygopalatine fossa. A total of 1.8 mL of 2% lidocaine with epinephrine 1:80,000 was administered in each case. Clinical effectiveness was evaluated using electric pulp testing (EPT) at selected anterior and posterior maxillary teeth, as well as pressure algometry at predefined palatal, buccal, and extraoral facial soft tissue sites. Successful pulpal anesthesia was defined as absence of EPT response at maximum output, whereas successful soft tissue anesthesia was defined as a pressure pain threshold exceeding 700 g. Preoperative dental anxiety was assessed using the Modified Dental Anxiety Scale (MDAS), while a second questionnaire recorded patient fear perception, procedural experience, and intension to repeat the same anesthetic technique. In parallel, a morphometric CBCT evaluation of 62 greater palatine canals was performed to analyze canal length, angulation, curvature, and anatomical variability. Results: Successful needle placement through the computer-guided protocol was achieved in 30 of 31 patients (96.7%), with a mean of 1.45 insertion attempts per case, indicating high procedural predictability and reproducibility. Pulpal anesthesia demonstrated a clear posterior-to-anterior gradient. The highest success rates were observed in posterior teeth, with 96.7% success in first molars and 93.3% in first premolars, whereas the central incisor demonstrated a reduced success rate of 50%. Posterior pulpal anesthesia was also associated with rapid onset and clinically useful duration, with mean onset times ranging from 5.5 to 6.3 minutes and duration ranging from 98.8 to 114 minutes. Soft tissue anesthesia showed excellent effectiveness in the palatal region, where complete success (100%) was achieved at all tested sites, accompanied by rapid onset (5.0–5.8 minutes) and prolonged duration (73.2–114 minutes). Buccal soft tissue anesthesia was more limited and followed a posterior-to-anterior decline, with the highest effectiveness at the first molar region (40%), followed by the first premolar (23.3%) and central incisor region (6.7%). Extraoral facial anesthesia was minimal. Patient-reported outcomes were highly favorable. Most participants presented low to moderate preoperative anxiety levels, while the post-procedural questionnaire demonstrated low perceived fear, positive overall experience, and high intension to undergo the same anesthetic method again. Morphometric analysis revealed a mean greater palatine canal length of 30.68 ± 2.69 mm and a total functional path length of 40.36 ± 3.20 mm. The mean canal-palatal plane angle was 69.69 ± 6.95°, while curved canal morphology predominated (88.3%). Conclusions: The use of a computer-guided surgical guide for maxillary nerve block through the greater palatine canal provides accurate, reproducible, and safe access to the maxillary nerve. Although anesthetic spread to anterior pulpal and buccal tissues remains anatomically limited, the technique demonstrated highly consistent effectiveness in the posterior maxilla and palatal tissues, with rapid onset, prolonged duration, and excellent patient acceptance. The method appears particularly promising for complex implant, sinus, and maxillary surgical procedures requiring profound and stable regional anesthesia.

Αντικείμενο της μελέτης: Σκοπός της παρούσας μελέτης ήταν η αξιολόγηση της δυνατότητας εφαρμογής, της ακρίβειας και της αναισθητικής αποτελεσματικότητας της υπολογιστικά καθοδηγούμενης τεχνικής στελεχιαίας αναισθησίας του άνω γναθικού νεύρου μέσω του πτερυγοϋπερώιου πόρου, με χρήση εξατομικευμένου χειρουργικού νάρθηκα. Μέθοδος: Σε 31 ασθενείς σχεδιάστηκαν και κατασκευάστηκαν εξατομικευμένοι νάρθηκες συνδυάζοντας σε ειδικό λογισμικό τα δεδομένα από υπάρχουσα προεγχειρητική υπολογιστική τομογραφία κωνικής δέσμης και ενδοστοματική ψηφιακή αποτύπωση. Η αποτελεσματικότητα της τεχνικής αξιολογήθηκε με ηλεκτρική δοκιμασία πολφού, μέτρηση του πόνου στην πίεση των μαλακών ιστών, καταγραφή του οδοντιατρικού άγχους και ερωτηματολόγιο εμπειρίας ασθενούς. Παράλληλα πραγματοποιήθηκε μορφομετρική ανάλυση 62 πτερυγοϋπερώιων πόρων. Αποτελέσματα: Η επιτυχής τοποθέτηση της βελόνας επιτεύχθηκε στο 96,7% των περιπτώσεων. Η πολφική και η αναισθησία των μαλακών ιστών εμφάνισαν υψηλά ποσοστά επιτυχίας κυρίως στην οπίσθια άνω γνάθο και στον υπερώιο βλεννογόνο, με ταχεία έναρξη και ικανοποιητική διάρκεια δράσης, ενώ στην πρόσθια περιοχή παρατηρήθηκε σαφώς μειωμένη αναισθητική απόκριση. Δεν καταγράφηκαν σοβαρές ανεπιθύμητες ενέργειες, παρά μόνο παροδικές οφθαλμολογικές διαταραχές σε μικρό ποσοστό ασθενών. Η αποδοχή της τεχνικής από τους ασθενείς ήταν ιδιαίτερα υψηλή. Συμπεράσματα: Η υπολογιστικά καθοδηγούμενη στελεχιαία αναισθησία του άνω γναθικού νεύρου μέσω του πτερυγοϋπερώιου πόρου αποτελεί μια κλινικά ακριβή και ασφαλή τεχνική, ιδιαίτερα χρήσιμη σε σύνθετες χειρουργικές επεμβάσεις της άνω γνάθου.