Digital surgery group versus traditional experience group in head and neck reconstruction: a retrospective controlled study to analyze clinical value and time-economic-social effect

Enhancing the accuracy of genioplasty using mixed reality and computer-aided design/manufacturing: a randomized controlled trial

Background

Genioplasty is performed as part of orthognathic surgery to correct jaw deformities. This procedure presents challenges in terms of osteosynthesis accuracy. This study aimed to evaluate the precision of preoperative planning in genioplasty using computer-aided design/computer-aided manufacturing (CAD/CAM) with three-dimensional (3D) printable biomaterials and mixed reality (MR) technology with a head-mounted display (Microsoft® HoloLens 2) and a registration marker.

Methods

Twenty-six patients underwent genioplasty using either only CAD/CAM devices (control group, n=10) or CAD/CAM with additional MR technology (experimental group, n=16). CAD/CAM devices were created based on virtual surgical planning (VSP), and MR holograms created based on VSP data were projected onto the surgical area using Microsoft HoloLens 2. After surgery, the planned model was compared with the postoperative computed tomography (CT) image, measuring the 3D surface and the differences in position and rotation using the root mean square deviation (RMSD) and Bland-Altman's method. Both analyses are blinded.

Results

The average 3D surface analysis errors within 2 mm ranged between 62.20-100.00% (control group) and 99.30-100.00% (experimental group), with mean errors of 92.12% and 99.81%, respectively. Errors within 1 mm ranged between 28.50-98.90% (control group) and 55.10-99.6% (experimental group) with mean errors of 67.36% and 85.60%, respectively. The largest RMSDs were 1.20 mm in the anteroposterior direction and 6.78° in pitch orientation for the experimental group and 1.78 mm in the anteroposterior direction and 6.04° in pitch orientation for the control group. A statistically significant difference between the two groups was observed for errors measured within 1 mm (P=0.047) and for yaw (P=0.003). No postoperative complications were observed in either group.

Conclusions

Using CAD/CAM with additional MR technology in genioplasty improved the repositioning accuracy of the chin bone fragment and plate placement, with statistically significant improvements in specific spatial directions. This combination of CAD/CAM and MR technology allows for intraoperative spatial verification of fragment movement according to preoperative VSP, which significantly contributes surgical precision.

Efficacy of digital zoning design for the resection of benign parotid gland tumor

The objective of this study is to verify the role of digital modified parotid tumor zoning method in modified parotid incision. The data of patients with parotid benign tumors from November 2021 to December 2023 were collected. Through the use of digital technology for soft tissue reconstruction, the parotid tumor was divided into four areas according to the digital image marker points. We designed the surgical incision according to the parotid gland division, found that it was feasible to guide the incision selection by division, and summarized the common incision and division corresponding, zone I was I and V-shaped incision, zone II was V incision, zone III was V and C- shaped incision, and zone IV was C- shaped incision. We conclude that the digital modified parotid gland zoning method can provide a better distinction in the surgical incision, and provide a better cosmetic incision and prognosis.

[Accurate tissue flap reconstruction method based on the quadratic surface developability for head and neck soft tissue defects]

Soft tissue defects resulting from head and neck tumor resection seriously impact the physical appearance and psychological well-being of patients. The complex curvature of the human head and neck poses a formidable challenge for maxillofacial surgeons to achieve precise aesthetic and functional restoration after surgery. To this end, a normal head and neck volunteer was selected as the subject of investigation. Employing Gaussian curvature analysis, combined with mechanical constraints and principal curvature analysis methods of soft tissue clinical treatment, a precise developable/non-developable area partition map of the head and neck surface was obtained, and a non-developable surface was constructed. Subsequently, a digital design method was proposed for the repair of head and neck soft tissue defects, and an in vitro simulated surgery experiment was conducted. Clinical verification was performed on a patient with tonsil tumor, and the results demonstrated that digital technology-designed flaps improved the accuracy and aesthetic outcome of head and neck soft tissue defect repair surgery. This study validates the feasibility of digital precision repair technology for soft tissue defects after head and neck tumor resection, which effectively assists surgeons in achieving precise flap transplantation reconstruction and improves patients' postoperative satisfaction.

An engineered biomaterial to harness the differentiation potential of endogenous human gingival mesenchymal stem cells (hGMSCs)

Here, we developed a stromal cell-derived factor-1a (SDF-1α) delivery biomaterial as an artificial polymeric-based niche with the ability to recruit local endogenous human gingival mesenchymal stem cells (hGMSCs) for craniofacial bone regeneration applications. Polydopamine-coated poly(ε-caprolactone) (PCL)-gelatin electrospun membranes were loaded with stromal cell-derived factor-1α (SDF-1α) via physical adsorption. Subsequently, the release profile of SDF-1α and the chemotactic capacity on human bone marrow mesenchymal stem cells (hBMMSCs) and hGMSCs were evaluated. The osteogenic differentiation capacity of the recruited MSCs was also assessed in vitro. Our results confirmed the sustainable release of SDF-1α from the developed biomaterial promoting the migration and homing of human bone marrow mesenchymal stem cells (hBMMSCs) and hGMSCs. Moreover, the results of the osteogenic differentiation assay showed that SDF-1α delivery significantly enhanced osteogenic differentiation of hBMMSCs and hGMSCs and up-regulated the gene expression of osteogenic markers compared to the control group. In conclusion, the current study successfully developed a novel and effective treatment modality for craniofacial bone regeneration by recruiting the autogenous progenitor cells including hGMSCs. The developed niches can potentially lead to the development of a novel platform for targeted manipulation of in vivo microenvironment to achieve efficient and safe craniofacial cell reprogramming, which also will pave the road to determine the capacity of local hGMSCs' contribution to in situ bone regeneration.