This page explains all relevant features on the Intrinsic Adjustments page of LaserCAM Prescribe for Vacuum Formed prescription.

Overview

Click Intrinsic Adjustments from the menu to access this page in LaserCAM Prescribe.

Page Layout

Page Fields

Arch Expansion

Arch Expansion, sometimes referred to as a Arch Fill, is a percentage (%) decrease in the height of the medial longitudinal arch (MLA).

This modification is based on the height of the Medial Arch Ref Point that is placed on the 3D scan during computer-aided design.

Available Selections	Percentage of Expansion
None	0%
Minimal	10%
Standard (Default)	20%
Maximum	30%

Clinicians are encouraged to mark the peak MLA location on the foot prior to 3D scan capture. Without marking this location on the scan the peak MLA location is left to the discretion of the individual undertaking the computer-aided design, which is often not the clinician. We highly recommend that you mark all recommended Ref Points prior to 3D scanning.

An orthotic laboratory may change the default percentages (%) for the Arch Expansion. These percentages are listed alongside the text option, e.g. - None (0%). Please be aware that the examples below are based on standard percentages and may not represent your laboratories specific configuration.

None (0%)

The None selection option indicates that the peak height of the MLA will be at the same height as the Medial Arch Ref Point.

Minimal (10%)

The Minimal (10%) selection option indicates that the peak height of the MLA will be 10% lower compared with the Medial Arch Ref Point.

Standard (20%)

The Standard (20%) selection option indicates that the peak height of the MLA will be 20% lower compared with the Medial Arch Ref Point.

Maximum (30%)

The Maximum (30%) selection option indicates that the peak height of the MLA will be 30% lower compared with the Medial Arch Ref Point.

Heel Expansion

Heel Expansion is a percentage (%) increase in the width of the heel from the widest points of the medial and lateral heel.

This modification is based on the width between the Medial Heel Ref Point and the Lateral Heel Ref Point that are placed on the 3D scan during computer-aided design.

Available Selections	Percentage of Expansion
None	0%
Minimal	5%
Standard (Default)	10%
Maximum	15%

None (0%)

The None (0%) selection option indicates that the width of the orthosis at the heel will be 0% wider than the width between the Medial Heel Ref Point and the Lateral Heel Ref Point.

Minimal (5%)

The Minimal (5%) selection option indicates that the width of the orthosis at the heel will be 5% wider than the width between the Medial Heel Ref Point and the Lateral Heel Ref Point.

Standard (Default) (10%)

The Standard (10%) selection option indicates that the width of the orthosis at the heel will be 10% wider than the width between the Medial Heel Ref Point and the Lateral Heel Ref Point.

Maximum (15%)

The Maximum (15%) selection option indicates that the width of the orthosis at the heel will be 15% wider than the width between the Medial Heel Ref Point and the Lateral Heel Ref Point.

Shell Width

Shell Width is a selection that determines the width of the forefoot of the Vacuum Formed orthosis.

This modification is very lab dependent so you should discuss the specific modelling with your laboratory.

For a precise Shell Width simply mark where you would like the widest portions of the shell to be directly on the foot prior to 3D scanning. This allows the individual undertaking the computer-aided design to reference these marks and provide you with a superior fit.

The image below shows an example of a cast with comprehensive markings. Not all are required, however marking the foot directly is an excellent way to decrease manufacturing error.

Available Selections	Mediodistal Forefoot Width	Laterodistal Forefoot Width
Standard (Default)	5mm wider than 1st MPJ	10mm wider than 5th MPJ
Super Slim	5mm narrower than 1st MPJ	In-line with 5th MPJ
Slim	In-line with 1st MPJ	5mm wider than 5th MPJ
Wide	10mm wider than 1st MPJ	15mm wider than 5th MPJ

Standard (Default)

The Standard selection option indicates that the orthosis will be 5mm wider than the 1st MPJ at the mediodistal forefoot, and 10mm wider than the 5th MPJ at the laterodistal forefoot.

Super Slim

The Super Slim selection option indicates that the orthosis will be 5mm narrower than the 1st MPJ at the mediodistal forefoot, and in-line with the 5th MPJ at the laterodistal forefoot.

Slim

The Slim selection option indicates that the orthosis will be in-line with the 1st MPJ at the mediodistal forefoot, and 5mm wider than the 5th MPJ at the laterodistal forefoot.

Wide

The Wide selection option indicates that the orthosis will be 10mm wider than the 1st MPJ at the mediodistal forefoot, and 15mm wider than the 5th MPJ at the laterodistal forefoot.

Shell Length

Shell Length is a selection that determines the width of the forefoot of the Vacuum Formed orthosis.

This modification is very lab dependent so you should discuss the specific modelling with your laboratory.

For a precise Shell Length simply mark where you would like the most distal portions of the shell to be directly on the foot prior to 3D scanning. This allows the individual undertaking the computer-aided design to reference these marks and provide you with a superior fit.

Available Selections
Standard (Default)
Long
Short

Standard (Default)

The Standard selection option indicates that the orthosis will be 10mm wider than the 1st MPJ at the mediodistal forefoot, and 15mm wider than the 5th MPJ at the laterodistal forefoot.

Long

The Long selection option indicates that the orthosis will be 10mm wider than the 1st MPJ at the mediodistal forefoot, and 15mm wider than the 5th MPJ at the laterodistal forefoot.

Short

The Short selection option indicates that the orthosis will be 10mm wider than the 1st MPJ at the mediodistal forefoot, and 15mm wider than the 5th MPJ at the laterodistal forefoot.

Plantar Fascia Accommodation (PFA)

A Plantar Fascia Accommodation (PFA), sometimes referred to as a Plantar Fascia Groove, is an accommodation at a specified depth (mm) in the top surface of the orthosis shaped according to a Curved, Straight or Scan style selection.

It is highly recommended that all prescriptions consider the accommodation of the plantar fascia. Not including an accommodation for the plantar fascia can result in patient discomfort.

The specified depth is measured prior to surface smoothing and is subject to minor variability.

Default Value	Minimum Value	Maximum Value	Default Selection	Available Selections
0mm	0mm	8mm	Curved	Curved
				Straight
				Scan

Curved

Adjustment Origin	Adjustment Insertion
Medial calcaneal tubercle	Inline with 1st metatarsal ~10mm proximal to 1st MPJ

Straight

Adjustment Origin	Adjustment Insertion
Medial calcaneal tubercle	Inline with 1st metatarsal ~10mm proximal to 1st MPJ

Scan

A Scan style selection will indicate to technicians that a marking has been made on the plantar fascia prior to 3D scanning, or has been indicated using the Make Drawing tool.

This is the most accurate method of Plantar Fascia Accommodation prescription.

Adjustment Origin	Adjustment Insertion
As per marking	As per marking

Skive

We recommend that you read the published works of Kevin Kirby to understand relevant theory prior to requesting this adjustment. We have used these works to inform how we recommend the application the Skive adjustment in a computer-aided design environment.

K. Kirby (1989), Rotational equilibrium across the subtalar joint axis, JAPMA

K. Kirby (1992), The medial heel skive technique: improving pronation control in foot orthoses, JAPMA

K. Kirby (2007), Determination of the subtalar join axis location by restriction of talocrural joint motion, JAPMA

A Skive is an adjustment that is achieved by orientating a flat plane relative to the aligned 3D foot scan during computer-aided design. This plane is orientated in relation to a marked subtalar joint axis, or at a specific angle, and pushed through the 3D foot scan at a specified depth.

	Default Value	Minimum Value	Maximum Value
Depth	0mm	0mm	10mm
Angle (°)	0°	-90° (lateral skive)	90° (medial skive)

There are two methods of prescribing a Skive. Please use the method available to you depending on your 3D scan hardware.

Prescription Variable	STJ Axis Method (Recommended Method)	Depth/Degree Method
Angle (°)	Not required	Required
Depth (mm)	Required	Required
3D Scan Type	Colour 3D Scan Only	Any 3D Scan

STJ Axis Method

RECOMMENDED METHOD

This method is only possible when using colour 3D scan formats such as VRML.

The image below shows the orientation of the adjustment relative to the STJ axis marked on the 3D scan (represented by the yellow line).

Using the STJ Axis Method the only variable required is the Skive Depth.

Skive Angle is not required as the orientation of the skive plane is based upon the marked STJ axis.

Depth/Degree Method

The Depth/Degree Method allows a user to enter a specific Skive Depth and Skive Angle.

Skive Depth

The Skive Depth directly effects the magnitude of supination or pronation moment applied to the subtalar joint. It is measured from the blue depth sphere placed on the 3D foot scan to the skive plane (see image below).

Skive Angle

The Skive Angle defines the frontal plane orientation of the skive plane. If the subtalar join axis is medially deviated then the Skive Angle should increase to ensure a supination moment is being applied to the subtalar joint.

The Skive Angle does not need to be specified when using the STJ Axis Method.

Inclination Angle

The Inclination Angle defines the sagittal plane orientation of the skive plane. The default value is set to Maximum Inclination, which is considered generally appropriate. Specific values may be requested.

Default Selection	Available Selections
Maintain Maximum Inclination	Maintain Maximum Inclination
	Zero Degree Inclination
	Specific Inclination (°)

Maintain Maximum Inclination

The image below shows a Skive with the Maximum Inclination of the skive plane.

Additional information regarding Inclination Angle can be found in the following article:

P. Harradine (2011), The medal oblique shell inclination technique: a method to increase subtalar supination moments in foot orthoses, JAPMA

Support

Search Vacuum Formed Prescription Guide

Related Articles

Page:

Vacuum Formed
Page:

Review Prescription - Vacuum Formed
Page:

Notes & Attachments - Vacuum Formed
Page:

Device Options - Vacuum Formed
Page:

Materials - Vacuum Formed

Submit Support Ticket

If you require further support, please submit a support ticket below.

Browser not supported