Vergleichende Analyse zweier Operationsplanungsverfahren für die Unterkieferrekonstruktion mit freien Knochentransplantaten hinsichtlich der postoperativen Präzision nach umfangreicher ablativer Chirurgie im Kopf-Hals-Bereich

Comparative analysis of two surgical planning procedures for mandibular reconstruction with free bone grafts with regard to postoperative precision after extensive ablative surgery in the head and neck region

by Ole Moritz Dr. Block
Doctoral thesis
Date of Examination:2024-10-29
Date of issue:2024-09-12
Advisor:Prof. Dr. Philipp Brockmeyer
Referee:Prof. Dr. Ralf Bürgers
Referee:Prof. Dr. Ralf Dressel
Persistent Address: http://dx.doi.org/10.53846/goediss-10683

 

 

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Abstract

English

Oral squamous cell carcinoma is one of the most common cancers worldwide. In advanced tumor stages, the tumor cells often grow invasively into the adjacent mandibular bone, making partial resection necessary. Both tumor progression and therapeutic measures are accompanied by a considerable loss of health-related quality of life, which makes functional and aesthetic reconstruction necessary. Today, mandibular reconstructions are planned and performed using preoperative virtual surgical planning (VSP) and the template-guided surgical implementation of this planning. The procedures described are both commercially available and can be performed in-house. In the present study, the advantages and weaknesses of a commercial and an in-house planning procedure were compared morphometrically with regard to postoperative precision. In this context, it was determined which factors are responsible for the deviations between planning and result and whether and how possible sources of error can be eliminated. The patient population consisted of a total of 29 patients with advanced oral squamous cell carcinoma and an indication for partial mandibular resection and reconstruction. In 15 patients, in-house surgical planning and execution was performed, in 14 patients a commercial procedure involving a patient-specific implant (PSI) was chosen. The analysis showed that the volumes of the planned and postoperatively reconstructed bone segments differed significantly in both in-house planning (p = 0.0431) and commercial planning (p < 0.0001). In addition, a significant deviation in the osteotomy angles was demonstrated in the in-house surgical planning (p = 0.0391). A direct comparison showed that commercial surgical planning was superior to in-house planning in the postoperative deviation of the entire mandible (p = 0.0217), the intersegmental space volumes (p = 0.0035) and the intersegmental space lengths (p = 0.0007). Only a few comparable studies are described in the current literature. Further multicentre studies with a large patient population and standardized measurement parameters would be desirable in this context. The following parameters were identified in this study as important influencing factors for postoperative precision: Intercondylar distance, osteotomy angle, surface overlay and volume and length comparison of the intersegmental spaces. The intersegmental spaces are of particular interest as they can have a major influence on graft ossification.
Keywords: mandibular reconstruction; oral squamous cell carcinoma (OSCC); precision; virtual surgical planning (VSP)