Intralesional curettage versus prosthetic replacement for bone tumors — a finite element analysis case of limb salvage simulation in biomechanics

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Highlights

Abstract

Background and objectives

To compare mechanical properties of femoral tumor treatments so that better operative strategy for limb tumors surgery is optimized.

Methods

Fourteen femoral CT images were randomly selected to rebuild 3D models by MIMICS. They were then executed by reverse engineering softwares for simulative modes. Mode #1: Intralesional curettage with cement filled plus fixator; Mode #2: Distal femur resection with tumorous prosthesis replaced. Finally, the mechanical aspects such as stress and displacement were compared by finite element analysis.

Results

Analyzed by AnSys, the observation indexes were measured as follows: for displacement of femurs, d=1.4762 (< a=3.9042 < c=3.9845 < b=4.1159) in mm is the most staple of all models; for displacement of implants (fixators or prostheses), it's similar to the behavior of femurs and with no significant difference; for stresses of femurs, no significant difference was found among all models; the stresses of implants (fixations and prostheses) were observed as d=39.6334 (< a=58.6206 < c=61.8150 < b=62.6626) in MPa correspondently, which is the least; for stresses of the general system, the average of peak values for integrated devices of all models are: d=40.8072 (< a=58.6206 < c=61.7831< b=62.6626) in MPa, which is also the least. As a final result, both maximum values for displacement and stress of mode 2 are lower than those of mode 1.

Conclusions

Our finite element analysis of limb salvage simulation in biomechanics proved that, to treat distal femoral bone tumors, prosthetic replacement is more efficient than intralesional curettage.

Introduction

Distal femur is the most common site for malignant bony tumors. Many surgeons treat tumors of extensive bone destruction with wide resection followed by prosthetic replacement, while some surgeons treat small tumors by intralesional curettage. Over the past decades, these limb salvage methods have evolved and substituted for amputation as the safe mainstay in most surgical cases. However, the best option for limb tumors and the risk factors for recurrence remain controversial. The aim of this paper is to compare the procedures of “Intralesional curettage” with “Prosthetic replacement” [1,2], and their clinical effects on implants will be numerically investigated by Finite Element Method to make suitable decision quantitatively. Finite Element Analysis (FEA) is executed to examine their biomechanical performance by simulation, e.g. identifying displacement throughout structures, and predicting the magnitude of maximal stress [3]. This present investigation was conducted to 2 modes based on comparison among 4 models for optimization during preoperative planning according to the physics emulation, and the insight of computerized findings will enable easier limb-salvage potentially.

In term of low-grade malignant bone tumors surgery assumed in this case, we hypothesized that computer aided methods can improve the accuracy of dissection compared to traditional freehand technique, allow precise planning of surgical excision, and develop allograft-prosthetic composite fitting in removal area. Thus, mathematical approximation must be carried out estimating mechanical behavior in order to design surgical resection prior to actual operation [3]. In our experiment, the disease areas were reconstructed three-dimensionally (3D), the cutting ranges were identified, the surgical templates were computer-aided maneuvered, the prosthesis was individualized, tumor resection and reconstruction were emulated [4], implants were installed and analyzed finitely. The primary process includes: by using trimming templates, preoperatively obtained allogeneic bones are trimmed into 3D shapes matching the bony defects after tumor excision; they are then fixed to metal prostheses with screws, bony cement or ingrowth to form individualized prostheses, and finally implanted into the defect areas [5].

Section snippets

Experimental material

The materials used for this experiment included: Femoral CT (Toshiba, Japan) scans of 14 normal volunteers, a Statistical Package for the Social Sciences 13.0 (SPSS, IBM, Chicago, USA), reverse engineering softwares such as Mimics 17.0 (Materialise, Leuvan, Belgium), Geomagic Studio-12.0 (3D Systems, Rock Hill, USA), UG-8.0 (Siemens, Germany), ProE-5.0 (Parametric Tech Corp, USA), Hypermesh-11.0 (Altair Engineering, USA), Finite Element Analysis software Ansys-14.0 (ANSYS, Inc. Pennsylvania,

Displacement of femur

The displacement distribution of the femurs in these 4 models were observed by reviewing Fig. 5, we noticed that the concentration region of peak displacement is at the top of the great trochanter, femoral head and acetabulum, values decrease gradually, concentrically and distally. The displacement directions are all downward vertically. P=0.004<0.05 suggests a significant difference while Kruskal-Wallis rank-sum is examined statistically addressing displacement. By comparison among these 4

Discussion

This experiment carried out computer aided modeling for surgical management of bony tumors, provided accurate tumor removal with salvage of unaffected bone maximally and precise endoprosthesis reconstruction. Through digital simulation, surgical implants were designed freely adjusting the residual bone. Additionally, the allogeneic bones were trimmed to 3D shapes matching the bone defect based on auxiliary template reducing margins, and they were then integrated to form custom fixtures [11]. On

Conclusion

Computer assisted simulation facilitates accurate resection and numerical examination for limb salvage surgery. After analyzed by finite element models regarding displacement and stress, the following senses were made that: theoretically, the implant of prosthesis is stapler than that of fixation; mechanically, the risk of bony fracture or implant breakage for intralesional curettage is higher than prosthetic replacement; clinically, prosthetic replacement is more preferable for treating distal

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of Guangzhou Medical University Committee (#2018Z04) and with the 1964 Helsinki declaration or comparable ethical standards.

Consent to participate

Informed consent was obtained from all participants included in the study.

Consent for publication

Individual person's data for publication are consent from all authors and participants included in the study.

Availability of data and materials

Data and materials are provided upon requested, please contact authors if applied.

Funding

This work is supported by

  • 1

    GuangDong Province Exemplary Base for Collaborative Postgraduate Cultivation 2020;

  • 2

    Guangzhou Bureau of Science & Technology granted Peak Hospital 2021;

  • 3

    Educational cultivation granted project of 1st Affiliated Hospital at Guangzhou Medical University (2018Z04) with financial role of additional ¥50K granted played;

  • 4

    Higher education reform granted project of Guangdong 2018, with statistical role of SPSS analysis played;

  • 5

    High Educational Postgraduate Innovation Plan

Declaration of Competing Interest

No author associated with this paper has disclosed any potential or pertinent conflicts which may be perceived to have impending conflict with this work.

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