Impact of CAD/CAM mandibular reconstruction on chewing and swallowing function after surgery for locally advanced oral cancer: A retrospective study of 50 cases

Trismus after partial maxillectomy and radiotherapy: Free flap reconstruction versus prosthetic obturation

OBJECTIVE

Partial maxillectomy and postoperative radiotherapy are both risk factors associated with trismus. This retrospective study aimed to evaluate the incidence and severity of trismus in patients following partial maxillectomy with or without postoperative radiotherapy and to compare free flap reconstruction and prosthetic obturation.

METHODS

A retrospective review of 40 oral cancer patients who underwent partial maxillectomy with or without postoperative radiotherapy was performed. Maximum interincisal distance recorded at least 6 months after surgery was classified according to a revised subjective-objective management-analytical (SOMA) scale and compared between the free flap reconstruction group (n = 12) and the prosthetic obturation group (n = 28).

RESULTS

Trismus was observed in 16/40 (40%) patients, and severe trismus was observed in 4/40 (10%) patients. Although no significant difference in trismus grade was observed between the free flap reconstruction and prosthetic obturation groups, both severe trismus and radiation-induced osteonecrosis were only seen in the prosthetic obturation group with postoperative radiotherapy.

CONCLUSION

Free flap reconstruction was preferable to prosthetic obturation to avoid severe trismus and radiation-induced osteonecrosis in patients who underwent both partial maxillectomy and postoperative radiotherapy.

The role of computer aided design/computer assisted manufacturing (CAD/CAM) and 3- dimensional printing in head and neck oncologic surgery: A review and future directions

Microvascular free flap reconstruction has remained the standard of care in reconstruction of large tissue defects following ablative head and neck oncologic surgery, especially for bony structures. Computer aided design/computer assisted manufacturing (CAD/CAM) and 3-dimensionally (3D) printed models and devices offer novel solutions for reconstruction of bony defects. Conventional free hand techniques have been enhanced using 3D printed anatomic models for reference and pre-bending of titanium reconstructive plates, which has dramatically improved intraoperative and microvascular ischemia times. Improvements led to current state of the art uses which include full virtual planning (VP), 3D printed osteotomy guides, and patient specific reconstructive plates, with advanced options incorporating dental rehabilitation and titanium bone replacements into the primary surgical plan through use of these tools. Limitations such as high costs and delays in device manufacturing may be mitigated with in house software and workflows. Future innovations still in development include printing custom prosthetics, 'bioprinting' of tissue engineered scaffolds, integration of therapeutic implants, and other possibilities as this technology continues to rapidly advance. This review summarizes the literature and serves as a summary guide to the historic, current, advanced, and future possibilities of 3D printing within head and neck oncologic surgery and bony reconstruction. This review serves as a summary guide to the historic, current, advanced, and future roles of CAD/CAM and 3D printing within the field of head and neck oncologic surgery and bony reconstruction.

Mandibular shape prediction model using machine learning techniques

OBJECTIVE

To create a mandibular shape prediction model using machine learning techniques and geometric morphometrics.

MATERIALS AND METHODS

Six hundred twenty-nine radiographs were used to select the most appropriate craniomaxillary variables in different craniofacial pattern classifications using a support vector machine. To obtain the three-dimensional mandibular shape, a Procrustes fit was used on 55 tomograms, in which 17 three-dimensional landmarks were digitized. A partial least square regression was employed to find the best covariation between craniomaxillary angles and the symmetric components of mandibular shape. The model was applied to a new sample of six tomograms and evaluated by the mean absolute error. Each mandible predicted was assessed using the Hausdorff distance (HDu) and a color scale. The model was also exploratively applied to six new radiographs.

RESULTS

Covariation was 88.66% with a significance of < 0.0001 explained by twelve craniomaxillary variables. Low differences between the original and predicted models were obtained, with a mean absolute error of 0.0143. The mean distance between meshes ranged from 0.0033 to 0.0059 HDu and each color scale demonstrated general similarity between the surfaces.

CONCLUSIONS

This approach offered promising results in obtaining a mandibular prediction model that enhances shape properties in an economical way and is applicable to a Latin American population. Clinical proof of this method will require further studies with larger samples.

CLINICAL RELEVANCE

This method offers a reliable, economic alternative to traditional mandibular prediction methods and is applicable to the Latin American population.

The geriatric-8 screening tool for predicting complications in older adults after surgery for locally advanced head and neck cancer with free flap reconstruction

PURPOSE

Radical surgery with free flap reconstruction for locally advanced head and neck cancer (HNC) is quite challenging for older adults. This retrospective study aimed to elucidate the usefulness of the geriatric-8 (G8) screening tool for predicting postoperative complications in older adults with HNC.

METHODS

A retrospective review of 37 older adults with HNC who underwent radical surgery with free flap reconstruction and were assessed by the G8 screening tool was performed. Postoperative complications during hospitalization were classified according to the Clavien-Dindo classification, and possible contributing factors, including the G8 score, for major and minor complications were subjected to univariate and multivariate analyses.

RESULTS

The appropriate G8 cut-off value for both major and minor complications was 12 (area under the curve 0.56 and 0.55, respectively). Multivariate logistic regression analysis showed that both smoking and lower G8 score (≤ 12) were independently associated with the severity of complications (p = 0.043, p = 0.034, respectively).

CONCLUSIONS

The G8 was a possible predictor of major and minor complications in older adults with HNC who underwent radical surgery with free flap reconstruction.