Bone NeoplasmsPREDALLNCT07653178
Predicting Allograft Volume in Orthopedic Oncology: Hemielipsoid Formula vs Intraoperative Fluid-Fill Measurement
An observational study of Bone Neoplasms and Musculoskeletal Neoplasms, run by Sakarya University at 1 site in Turkey (Türkiye).
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Bone Neoplasms, Musculoskeletal Neoplasms, Bone Transplantation
- What is being tested?
- Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume Estimation
- Type of treatment
- Surgery or procedure
- How many people
- 40 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Jun 2026to 1 Jul 2027
- How long will I take part?
- 1 Day
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
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.
Who may be able to join
- 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
Who cannot join
- 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)
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Sakarya University Training and Research Hospital
Sakarya
About this study
Official title: Preoperative Bone Defect Volume Estimation Using the Hemielipsoid Formula for Allograft Planning in Musculoskeletal Tumor Surgery: A Prospective Validation Study Against Intraoperative Fluid Displacement Measurement
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).
Read the detailed description
Background: In orthopedic oncology, structural allograft reconstruction following primary musculoskeletal tumor resection requires precise preoperative planning. Currently, allograft selection at our institution relies on the surgeon's intraoperative visual estimation, with no standardized preoperative volumetric assessment protocol in place. This approach may result in allograft waste due to oversized graft selection, which is particularly problematic given the limited availability of allograft bank resources.
Rationale: The hemielipsoid formula (V = 4/3 × π × a × b × c / 2) offers a simple, reproducible method for estimating irregular bone defect volumes from standard cross-sectional imaging. If validated against an intraoperative reference standard, this formula could serve as a practical preoperative planning tool to guide allograft selection and minimize unnecessary graft use.
Study Design: This is a single-center prospective observational study conducted at Sakarya University Training and Research Hospital, Department of Orthopedics and Traumatology.
Preoperative Assessment: Defect volume will be estimated by the operating surgeon using the hemielipsoid formula applied to routine preoperative CT imaging. The three principal dimensions of the anticipated resection defect (length, width, and depth) will be measured on axial, coronal, and sagittal CT reconstructions, and volume will be calculated accordingly.
Intraoperative Assessment: Following tumor resection, the actual bone defect volume will be measured by direct cavity fluid displacement as the intraoperative reference standard. The resection cavity will be filled with a measured volume of saline to determine the true defect volume.
Outcome Assessment: The primary outcome is the agreement between preoperative hemielipsoid-estimated volume and intraoperative fluid displacement-measured volume, assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC). The secondary outcome is the correlation between preoperative volume estimation and actual allograft volume used, to evaluate the utility of the hemielipsoid formula in reducing intraoperative allograft waste.
Sample Size: A priori power analysis was performed based on intraclass correlation coefficient (ICC) estimation (H0: ICC = 0.70; H1: ICC = 0.90; two-tailed alpha = 0.05; power = 0.80) using the Fisher z-transformation method, indicating a minimum required sample size of 25 patients. Target enrollment was set at 40 patients to account for a 10% dropout rate and to allow for potential subgroup analyses.
- Being tested
- Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume Estimation
- Keywords
- hemielipsoid formula, bone defect volume, allograft, oncology, orthopedic oncology
- Medical subject headings
- Bone Neoplasms, Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume EstimationProcedure or surgery
Also called Fluid Displacement Intraoperative Measurement
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: Procedure: Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume Estimation |
What is being measured
The primary outcome is the main question the study is designed to answer.
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
Measured: Intraoperative (Day 1)
Secondary outcomes (1)
Allograft waste volume
Difference between allograft volume prepared and actual volume used, compared between hemielipsoid-guided and historical surgeon estimation
Measured: Intraoperative (Day 1)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Jun 2026
- Study start1 Jun 2026
- Primary completion1 Jun 2027 (estimated)
- Study completion1 Jul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Bone NeoplasmsStudies of the same condition, open and under way.
- More trials run by Sakarya UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 40 participants (estimated)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Sakarya University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07653178
- Sponsor's protocol ID
- E-43012747-050.04-543070-646
- Acronym
- PREDALL
- Status last verified
- Jun 2026
- First submitted
- 11 Jun 2026
- Last updated
- 30 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared publicly due to patient privacy considerations and institutional policy.
Study at a glance
From the registry record, last updated by the sponsor on 30 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Preoperative Bone Defect Volume Estimation Using the Hemielipsoid Formula for Allograft Planning in Musculoskeletal Tumor Surgery: A Prospective Validation Study Against Intraoperative Fluid Displacement Measurement
- ClinicalTrials.gov ID
- NCT07653178
- Acronym / sponsor ID
- PREDALL / E-43012747-050.04-543070-646
- Keywords
- hemielipsoid formula, bone defect volume, allograft, oncology, orthopedic oncology
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Sakarya UniversityUniversity, hospital or other
- Study start
- 1 Jun 2026 (actual)
- Primary completion
- 1 Jun 2027 (estimated)
- Study completion
- 1 Jul 2027 (estimated)
- First posted
- 17 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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).
Detailed description
Background: In orthopedic oncology, structural allograft reconstruction following primary musculoskeletal tumor resection requires precise preoperative planning. Currently, allograft selection at our institution relies on the surgeon's intraoperative visual estimation, with no standardized preoperative volumetric assessment protocol in place. This approach may result in allograft waste due to oversized graft selection, which is particularly problematic given the limited availability of allograft bank resources.
Rationale: The hemielipsoid formula (V = 4/3 × π × a × b × c / 2) offers a simple, reproducible method for estimating irregular bone defect volumes from standard cross-sectional imaging. If validated against an intraoperative reference standard, this formula could serve as a practical preoperative planning tool to guide allograft selection and minimize unnecessary graft use.
Study Design: This is a single-center prospective observational study conducted at Sakarya University Training and Research Hospital, Department of Orthopedics and Traumatology.
Preoperative Assessment: Defect volume will be estimated by the operating surgeon using the hemielipsoid formula applied to routine preoperative CT imaging. The three principal dimensions of the anticipated resection defect (length, width, and depth) will be measured on axial, coronal, and sagittal CT reconstructions, and volume will be calculated accordingly.
Intraoperative Assessment: Following tumor resection, the actual bone defect volume will be measured by direct cavity fluid displacement as the intraoperative reference standard. The resection cavity will be filled with a measured volume of saline to determine the true defect volume.
Outcome Assessment: The primary outcome is the agreement between preoperative hemielipsoid-estimated volume and intraoperative fluid displacement-measured volume, assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC). The secondary outcome is the correlation between preoperative volume estimation and actual allograft volume used, to evaluate the utility of the hemielipsoid formula in reducing intraoperative allograft waste.
Sample Size: A priori power analysis was performed based on intraclass correlation coefficient (ICC) estimation (H0: ICC = 0.70; H1: ICC = 0.90; two-tailed alpha = 0.05; power = 0.80) using the Fisher z-transformation method, indicating a minimum required sample size of 25 patients. Target enrollment was set at 40 patients to account for a 10% dropout rate and to allow for potential subgroup analyses.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
- Target follow-up
- 1 Day
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Hemielipsoid Volume Estimation Group | – | Procedure: Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume Estimationatients 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (5 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Hemielipsoid Formula-Based Preoperative and Intraoperative Bone Defect Volume EstimationAlso: Fluid Displacement Intraoperative MeasurementPreoperative 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. | Procedure or surgery | Hemielipsoid Volume Estimation Group |
Primary outcome
Agreement between preoperative hemielipsoid-estimated and intraoperative fluid displacement-measured bone defect volume
Time frame: Intraoperative (Day 1)
Assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC) between the two volumetric measurement methods
1 secondary outcome
Allograft waste volume
Time frame: Intraoperative (Day 1)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jun 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared publicly due to patient privacy considerations and institutional policy.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Bone Neoplasms and Musculoskeletal Neoplasms, run by Sakarya University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 30 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Agreement between preoperative hemielipsoid-estimated and intraoperative fluid displacement-measured bone defect volume (time frame: Intraoperative (Day 1)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jun 2026.