Scoliosis Braces

This case study demonstrates the ISF process being used in a medical context, and is representative of many similar applications categorised by the need for plastic-forming moulds and per-patient customisation.

Background: bespoke braces for adolescent scoliosis

Scoliosis, an abnormal curvature of the spine, affects around 2-3 percent of the population and usually starts in children aged 10 to 15.

For adolescent patients whose skeletons are still changing, progression of the curvature can be prevented with the use of a brace. Back braces can also provide pain relief to adults by supporting the spine, or may be used if a patient is unable to undergo an operation.

Braces must be produced on a per-patient basis as each scoliosis patient has a unique spinal curvature. Current methods involve one of the following:

  • Modifying prefabricated moulds.

  • Modern alternative — milling a mould geometry based on data provided by X-rays and 3D scans.

ISF Steps

  1. An X-Ray of the patient is taken. This will be used to assess how the curved spine can be corrected.

  2. A 3D scan of the patient is taken and imported into CAD software. ISF geometry is modelled to fit the patient.

  3. The geometry is adapted to be manufactured using ISF.

  4. A toolpath is generated to be used by a CNC machine.

  5. The part is formed.

  6. The part can be used directly within a brace as a reinforcing panel, or:

  7. The part can be used as a mould to vacuum form HDPE brace components.

Benefits

  • ISF would allow brace producers to continue to take full advantage of recent improvements to detailed per-patient customisation.

  • By using an inexpensive metal sheet to produce each mould, costs and wastage could be reduced.

  • The speed at which unique geometry can be produced could lead to a reduction in lead times for patients, especially as workflows through CAD modelling and toolpath generation are further refined.

Viability

  • Materials like the titanium alloys that may be used in medical applications can currently be difficult to process.

  • There is currently no widely-available commercial toolpath generator for ISF geometries.

  • A full brace or mould cannot be produced from a single sheet of metal.