Predicting Allograft Volume in Orthopedic Oncology: Hemielipsoid Formula vs Intraoperative Fluid-Fill Measurement

NCT07653178 | Active Not Recruiting

• 1 other identifier: E-43012747-050.04-543070-646
• Study Type: observational
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Bone defects following primary musculoskeletal tumor resection are frequently reconstructed using structural allografts. Allograft availability is limited, and intraoperative waste due to oversized graft selection remains a practical challenge in orthopedic oncology. Accurate preoperative estimation of the expected defect volume is therefore critical not only for surgical planning but also for minimizing unnecessary allograft use. This prospective study aims to evaluate the accuracy of the preoperative hemielipsoid formula in estimating bone defect volume after primary musculoskeletal tumor resection, using intraoperative fluid displacement as the reference standard. A secondary aim is to determine whether preoperative CT-based hemielipsoid volume calculation can reliably guide allograft selection and reduce intraoperative graft waste. Patients scheduled for primary musculoskeletal tumor resection with structural allograft reconstruction at Sakarya University Training and Research Hospital will be enrolled. Preoperative defect volume will be estimated using the hemielipsoid formula (V = 4/3 × π × a × b × c / 2) derived from preoperative CT measurements. Intraoperative defect volume will be measured by fluid displacement as the reference standard. Agreement between methods will be assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC).

Conditions

Bone Neoplasms; Musculoskeletal Neoplasms; Bone Transplantation

Keywords

hemielipsoid formula; bone defect volume; allograft; oncology; orthopedic oncology

Outcome Measures

Primary Outcomes (1)

• Agreement between preoperative hemielipsoid-estimated and intraoperative fluid displacement-measured bone defect volume

  Assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC) between the two volumetric measurement methods

  Intraoperative (Day 1)

Secondary Outcomes (1)

• Allograft waste volume

  Intraoperative (Day 1)

Study Arms (1)

Hemielipsoid Volume Estimation Group

atients undergoing primary musculoskeletal tumor resection with structural allograft reconstruction. Preoperative bone defect volume is estimated using the hemielipsoid formula from CT imaging. Intraoperative defect volume is measured by saline cavity fill displacement as the reference standard.

Procedure: Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume Estimation

Interventions

Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume Estimation PROCEDURE

Preoperative bone defect volume is estimated by the operating surgeon using the hemielipsoid formula (V = 4/3 × π × a × b × c / 2) applied to routine preoperative CT imaging. The three principal dimensions of the anticipated resection defect are measured on axial, coronal, and sagittal CT reconstructions. Intraoperative defect volume is measured by saline cavity fill displacement as the reference standard. No additional procedures beyond standard surgical care are performed.

Also known as: Fluid Displacement Intraoperative Measurement

Hemielipsoid Volume Estimation Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients scheduled for primary musculoskeletal tumor resection with structural allograft reconstruction at the Department of Orthopedics and Traumatology, Sakarya University Training and Research Hospital. All patients are evaluated by a multidisciplinary oncology team prior to surgical planning.

You may qualify if:

• Patients diagnosed with a primary musculoskeletal tumor requiring surgical resection
• Structural allograft reconstruction planned following resection
• Routine preoperative CT imaging available for hemielipsoid measurements
• Age ≥ 18 years
• Written informed consent obtained

You may not qualify if:

• Metastatic bone tumors
• Pathological fracture at the resection site precluding accurate volume estimation
• Prior surgery at the same anatomical site
• Unavailability of adequate preoperative CT imaging
• Reconstruction planned with implant or autograft only (no structural allograft)

Sponsors & Collaborators

• Sakarya University: lead

Study Sites (1)

Sakarya University Training and Research Hospital

Sakarya, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Bone Neoplasms; Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Bone Diseases; Musculoskeletal Diseases

Study Design

• Study Type: observational
• Observational Model: CASE ONLY
• Time Perspective: PROSPECTIVE
• Target Duration: 1 Day
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 11, 2026
• First Posted: June 17, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): July 1, 2027
• Last Updated: June 30, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)