Parametrizing the genioplasty: a biomechanical virtual study on soft tissue behavior

Abstract Purpose Sliding genioplasty is used to surgically correct a retruded or misaligned chin: in this procedure, an osteotomy is performed and the bony segment is repositioned. In this study we investigate the effect of surgical parameters (bony segment movement, osteotomy design) on postop soft tissue changes in a patient cohort. Methods Seven patients were retrospectively recruited. Cone beam computed tomography data were obtained and soft tissue and bone shape reconstructions were performed. 3D models were created and surgical cuts were replicated according to postop scans. Each model was imported in ANSYS 2019R1 (Ansys Inc, USA) for simulation: the effect of variation in osteotomy plane as well as extent of bony segment movement were assessed by means of design of experiment: surgical parameters were varied in a surgically acceptable range and the soft tissue predictions were evaluated as displacement output of five craniometric landmarks. Results Simulation results show the overall changes of the lower third of the face are sensitive to changes in horizontal and vertical displacement of the bony segment as well as segment rotation. No significant changes in the soft tissue response were to attribute to the osteotomy design. Conclusions Our results are consistent with experimental findings reported in the literature: when planning genioplasty in orthognathic surgery, particular focus on the segment movement (horizontal translation, vertical translation and rotation), rather than on the design of the osteotomy itself, should be considered.

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Soft Tissue Response to Upper Incisor Retraction in Boys

British Journal of Orthodontics ◽

10.1179/bjo.1.5.199 ◽

1974 ◽

Vol 1 (5) ◽

pp. 199-204 ◽

Cited By ~ 52

Author(s):

Per Johan Wisth

Keyword(s):

Soft Tissue ◽

Individual Case ◽

Tissue Response ◽

Lower Lip ◽

Tissue Changes ◽

Incisor Retraction ◽

Treatment Changes ◽

Morphological Differences ◽

Soft Tissue Changes ◽

Soft Tissue Response

The paper describes the lip morphology and treatment changes in two groups of boys with slight (3–4 mm) and marked (8–10 mm) overjets. The results show that the initial morphological differences are greatest in the lower lip and these are maintained even after treatment. In individuals with a small overjet, the upper lip response is more closely related to the degree of incisor retraction than in individuals with marked overjet. Correction of the great overjets results in approximately similar upper and lower lip retraction. The results generally show great variability, and thus indicate that prediction of soft tissue changes in an individual case is difficult.

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Comparing the Responses of Osseous Versus Soft-Tissue Metastases of Renal Cell Carcinoma to Receptor Tyrosine Kinase Inhibitors and Immunotherapy

Kidney Cancer ◽

10.3233/kca-200094 ◽

2020 ◽

Vol 4 (3) ◽

pp. 151-158

Author(s):

Katherine Yuxi Tai ◽

Jad M. El Abiad ◽

Carol D. Morris ◽

Mark Christopher Markowski ◽

Adam S. Levin

Keyword(s):

Renal Cell Carcinoma ◽

Soft Tissue ◽

Cell Carcinoma ◽

Receptor Tyrosine Kinase ◽

Renal Cell ◽

Kinase Inhibitors ◽

Tissue Response ◽

Bone Response ◽

Soft Tissue Response ◽

Receptor Tyrosine Kinase Inhibitors

BACKGROUND: Checkpoint inhibitors and receptor tyrosine kinase inhibitors (RTKIs) have changed the standard of care for metastatic renal cell carcinoma (mRCC). Anecdotal evidence suggests these therapies may be less effective for treating bone than soft-tissue metastases. PURPOSE: We performed a retrospective review evaluating the relative clinical responses in soft-tissue and bone metastases in patients undergoing therapy using RTKIs and anti-programmed death-1 (PD-1) agents for mRCC. METHODS: Of the 2,212 patients in our institutional cancer registry with renal cell carcinoma (1997–2017), 68 (82 disease courses) were identified with measurable bone and soft-tissue metastases treated with RTKIs and/or PD-1s. Extent of metastasis was quantified at the time of therapy initiation (baseline) and at 3 months, 6 months, and 1 year. Changes in disease status were categorized as complete response, partial response, stable, mixed, or progression of disease according to RECIST v1.1 and MD Anderson criteria. These categories were further organized into “response to treatment” or “evidence of progression” to generate a generalized linear effects model with soft-tissue response as the independent variable and bone response as the dependent variable. Alpha = 0.05. RESULTS: Soft-tissue response correlated with bone response at 3 months (76 disease courses, p = 0.005) and 6 months (48 disease courses, p = 0.017). Of the patients with controlled soft-tissue disease, only 14 (19%) and 15 (32%) had progression in bone at 3 and 6 months, respectively. CONCLUSION: Contrary to anecdotal reports, osseous metastases do not appear to respond worse than soft-tissue metastases to treatment with these agents.

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