BACKGROUND AND OBJECTIVES

Treatment of primary bone and soft tissue sarcomas typically includes complete surgical resection with or without adjunctive modalities. Despite best efforts, for the most challenging clinical scenarios such as axial or pelvic sarcoma, five-year survival rates are reported to be between 27 and 40 %. Since quality of resection is a key determinant of oncologic outcomes, it is critical to preoperatively plan the surgical approach to improve resection accuracy, ensure sufficient surgical margins, and reduce the risk of local or metastatic recurrence. The computer conversion of 2-dimensional (2D) computerized tomography (CT) and magnetic resonance imaging (MRI) to a three-dimensional (3D) virtual reality (VR) avatar image may allow improved preoperative estimation of tumor size, location, adjacent anatomy, and spatial understanding of the tumor without relying on surgeon experience, memory, and imagination. The purpose of this study is to investigate the utility of a virtual reality platform in preoperative planning and surgical approach in a retrospective cohort of pelvic bone sarcoma cases.

METHODS

The histopathology database at our institution was queried for all historical cases of bone and soft tissue sarcoma , defined as positive gross or microscopic margins. Four cases of pelvic bone sarcoma were chosen for retrospective review by fellowship-trained orthopedic tumor specialists. For each case, participants first studied conventional 2D preoperative CT images and answered a questionnaire pertaining to objective case parameters. Participants then interacted with case-specific 3D models while wearing a VR headset and answered the same questionnaire. The VR 'avatar' was created with custom-developed software. After using both modalities, participants completed a Likert-scale survey aiming to evaluate the VR technology's subjective impact on understanding tumor environment, surgical plan confidence, and its ability to improve communication with colleagues and patients. Four attending orthopedic oncologists, one orthopedic oncology fellow, and one senior orthopedic oncology resident participated in the study.

RESULTS

Four cases of failed resection were evaluated by a group of both attending surgeons and a group of trainees composed of both residents and fellows. Tumor borders were clearly delineated in 0 % and 66.6 % cases when evaluating with conventional 2D imaging and VR, respectively. Participants changed adjacent structure involvement grade 22.2 % of the time after assessing involvement grade on the VR technology, with adjacent ligamentous structure grading changed most frequently in 55.5 % of cases. Users reported they would change the surgical approach or margins 44.4 % of the time after reviewing with VR technology. Initial 6 plane resection plans were changed in every user case. Subjective responses indicated that surgeons expressed more confidence in their approach, confidence with obtaining negative margins, and provided more detail regarding structures to be resected in specific planes.

CONCLUSION

Pelvic tumors present unique surgical challenges due to complex 3D anatomy, the proximity of vital structures, consistency of the tumor, and the need to alter patient position during resection procedures. Using examples of failed pelvic bone sarcoma resections, our study found that VR imaging increased understanding of the tumor environment, characteristics, and ability to communicate with patients and colleagues.