This interim report summarizes a project to develop a parametric model of the human spine to model scoliosis. The objectives are to create parametric models of individual vertebrae based on existing anatomical data and modeling techniques, and assemble them into a full parametric spine model that can be adjusted for scoliosis. So far, the student has conducted a literature review on relevant anatomy, modeling approaches, and existing data, and begun parameterizing vertebrae based on key dimensions and relationships between regions. Next steps include completing vertebrae models, assembling the full spine, adding an angular adjustment method, validating the model, and finishing the report.

1. Department of Mechanical Engineering
Develop a Parametric model of a child’s spine
to model scoliosis.
Student name:Valentin Ioan Dascalescu
Student number: X00097718
Supervisor:TonyTansey
( Interim Report)

2. Introduction:

3. The main objective of this project is to
develop a parametric model
framework of the human spine based
on a command file system by
combining different modelling
technics with vertebra and spine
parameters which are deduced from
existing anthropometric data bases .
Secondary objective will be
completing a conclusive literature
review of relevant scientific journals
and peer reviewed papers that will,
provide a better understanding of the
project and, generate a guide for the
completion of it.
Project Objectives:

4. Literature review:
In vitro, in vivo
and in silico
methodologies.
Anatomy of the
spine.
Anatomy of the
vertebrae
Modelling
techniques.
Medical imaging
methods.
Existing models of
the human spine
and vertebra.
Anthropometric
data base.
Validation

5. • Obtaining vertebra dimensions from computer tomography (CT) scans.
• A precise segmentation of a full vertebra from a CT scan is a challenging process and it is affected by various factors
such as: complex anatomical structure, unclear object boundaries, similar structures in near vicinity and degenerative
deformities
• (images: Akyokus, Meram, Konya, Turkey : Journal of Craniovertebral Junction&Spine, 2015, Vol. 6. )
Modelling the Scoliotic spine:

6. Modelling from stereo lithography (STL) type file:
Based on the knowledge obtained from the literature review, it was decided to model the geometry of the
parametric vertebrae from STL files using primitives such as: circles, ellipses and cylinders. The resulting
models are very close approximation of the vertebrae.
STL
file
Solid
model

7. Parameterization
Process of the
vertebrae in PTC Creo
1.Vertebra height is obtained
from subtracting the hip
height from the shoulder
height and dividing by the
number of vertebrae. Data is
selected from
http://dined.io.tudelft.nl/en
2. Using Panjabi et all
1911,1992 data sets,
together with published
data, the main parameters of
the vertebrae are identified.
3. Using assumptions and
critical parameters the
correlating relations between
the main vertebra regions are
formulated.
4. New parametric
vertebrae are generated.
They have a direct linear
relation to the master
vertebra model.
Picture of the vertebra
here
Geometry control by parameterisation

8. Parameterisation of the master vertebrae:
• When using a CAD type software, a
geometry entity can be defined by
dimensions.
• In parametric modelling is the dimensions
that drive, define, the geometry.
• The advantage is that, once the key
elements of a geometry entity are captured
in the drawing, they could all be related to
each other or to a driving parameter, so that
later on, the geometry could by altered or
modified by changing that respective
parameter
• http://dined.io.tudelft.nl/en/database/intr
oduction.
• The most in-depth and complete resource
of data is provided by the Panjabi et all
• “Thoracic Human Vertabrae-
Quantitative 3-Dimensional Anatomy,.
Spine. August, 1991,Vol. 16.”

9. Parameters and relations:
Nomenclature of vertebra defining parameters
Spine Deformity. November, 2013,Vol. 1, 6.
Parameters prediction formulae (M. Haghpanahi, M. Javadi,.
December, Narmak Ave., Tehran, Iran : Science Direct, 2011. )

10. Panjabi et all Spine 1992
Data collection
Datasets were compiled by direct measuring and by statistical analysis such as linear regression, mean and standard deviation

11. Lengths of the thoracic, lumbar and combined spine lengths by age with minimums and maximums
(Normal growth of the spine and skeletal maturation, Seminars in spine surgery 2015).

12. Project progress so far (15/12/2015)

13. Future course of action:
Create
parameterised
vertebrae for cervical
and thoracic region.
Create equation of
the spine.
Assemble the spine
model.
Create method which
allows for angular
adjustment.
Model validation
against in vitro data.
Finish writing the
report.
Analysis.
Output calculations
sheet.
Output sectioned
assembly sheet.
Output drawings
with angular
adjustment.

14. Thank you for your attention! Any questions ?