LOW COST LASER ALIGNMENT SYSTEM: A NEW APPROCH

www.wjpps.com Vol 5, Issue 2, 2016.

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Singh et al. World Journal of Pharmacy and Pharmaceutical Sciences

LOW COST LASER ALIGNMENT SYSTEM: A NEW APPROCH

Kumarpal Singh1* and Smita Nayak

2

1MPO, National Institute for the Orthopedically Handicapped.

2MPO, Workshop Manager, National Institute for the Orthopedically Handicapped.

ABSTRACT

The alignment instrument is a prime importance of the fabrication of

orthosis and prosthesis. Usually in Lower Limb Prosthesis Plumb-bob

is used as a weight bearing line. It helps to check the Anterior-posterior

and Medial-lateral static bench alignment but It need much more

experience and skill to handle a plumb-bob for alignment and it does

not provide an exact Angular relation ship between socket and pylon

(socket extension piece). To overcome this accuracy and angulations

factor the laser beam Laser Aligner is introduced. These types of

aligner provide accuracy in linear and angular relation between

prosthesis assemblies. Most of Laser aligner cost between Rs. 25.000

to 2, 00,000. It is an effort to achieve Function in prosthesis and

orthosis by aligning with low cost and minimum technology applied aligner to improve

quality of life of patients.

KEYWORDS: Anterior-posterior, Medial-lateral, prosthesis and orthosis.

INTRODUCTION

Alignment of prosthesis is defined as the position of the socket relative to the other prosthetic

components of the limb. During dynamic alignment the prosthetist, using subjective

judgment and feedback from the patient, aims to achieve the most suitable limb geometry for

best function and comfort. Prosthesis acceptability depends on several factors including

cosmesis, mass properties of the prosthesis, comfort, and function. Comfort and function are

directly dependent on the quality of fit of the socket, the quality of suspension, the type of

components used and the relative geometrical position of these components to each other.

The position and orientation of these components, the major elements being the socket,

joint(s), and terminator (e .g. foot), are defined as the alignment of the prosthesis. [1]

WORLD JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES

SJIF Impact Factor 5.210

Volume 5, Issue 2, 1130-1146 Research Article ISSN 2278 – 4357

Article Received on

08 Dec 2015,

Revised on 29 Dec 2015,

Accepted on 20 Jan 2016

*Correspondence for

Author

Kumarpal Singh

MPO, National Institute

for the Orthopedically

Handicapped.


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Over the years many different mechanical devices to aid in fitting and alignment of lower-

extremity prostheses have been developed to help in the application of one or another

particular set of alignment principles in use by individual titters. Others of these devices are

more general in application and are adaptable for use by any prosthetist regardless of the

particular alignment principles he advocates. In every case, however, an attempt has been

made to improve the fitting and alignment technique by adopting one definite set of

principles and using a mechanical device to aid in the application of those principles. "plumb-

line" method of alignment, a method which, essentially, assumes that the prosthesis carries

weight along a vertical plumb line, the elements of the prosthesis then being arranged using

this line as a reference. Still in general use throughout Europe and the United States, this

system involves the problem of determining the location of the plumb line in the socket so

that it can be extended down to the foot and used as a reference. Holding the plumb line

needs experience and skill. When we place the string of the plumb bob at reference point, the

weight moves freely and it takes time to come in static position.

Precision shifting of component in slight amount of degree or angle is not possible. The

pitting stool, Pivot point balancing device, Vise type fitting stand, Schneider’s alignment

stand, alignment duplication jig are the other common alignment methods used to check the

prosthesis or as a educational aid. The accuracy of these devices is unknown and mostly

followed by the trial and error methods. Although many manufacturers of prosthetic

components give static alignment recommendations from clinical experience using

theoretical alignment reference lines, these general guidelines do not reflect individual

differences. Furthermore, there is a worldwide controversy regarding different alignment

guidelines.[2,3,4]

The LASER aligner is used most commonly now a day by various

rehabilitation centers and prosthetic manufactures but it was not readily available due to its

high cost. So this is an attempt to provide a low cost laser alignment device that can be used

by the low economic country.

MATERIAL AND METHODS

Parts Selection for Low cost LASER aligner

1.Tripod stand

2.Chassis

3.Outer body

4.Reflection plates (c shape)


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5.LASERs

6.Battery

7.Switches

8.Connecting wire

9.Charging indicator

10. Angle reading plate (Full circle protractor)

11. charger

1.Tripod Stand

The stand to be fabricated having three adjustable legs or may be one leg having telescopic

movement, so as to obtain height adjustment of the instrument according to the need of

alignment. This stand has a control plate at the top that provide platform to connect the laser

aligner.

This platform allow rotation of LCLA in three plane.

Table 1: Material, specification and cost used for Tripod stand

Serial No. Name of Part Material Dimension Price in Rs.

1. Base Polypropylene

Height- 92mm

Outer dia.-125mm

Inner dia – 123mm

10.00

2. First Extension

Pipe Aluminum

Length- 380mm

Outer dia.-26mm

Inner dia.-24mm

67.00

3. Second Extension

Pipe Aluminum

Length- 400mm

Outer dia. –22mm

Inner dia.-20mm

45.00

4. Third Extension

Pipe Stainless steel

Length- 270mm

Outer dia. –16mm

Inner dia.-14mm

30.00

5. Other fabricating charges (lock fixing, welding etc 45.00

Total 197.00

Assembling of stand

Cut the upper surface of the “CD Container” and fill it with plaster of Paris, and fix 3rd

pipe

of outer diameter 26mm inside it vertically. Connect 2nd

pipe with 3rd

pipe and 1st pipe with

2nd

pipe accordingly. Fix a stand adaptor with the base of LCLA as shown in fig 1and 2.


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Fig 1: Stand pipes with base

Fig 2: Control plate with laser aligner

2. Chassis

A chassis consists of an internal frame that supports a man-made object in its construction

and use. It also allows the lasers in adjustment for fix in preposition.

Table 2: Material, dimensions and cost for the chassis

S. No. Name of Part Material Dimension Price in Rs.

1. Cylinder PP

Length- 26mm

Outer dia.-20mm

Inner dia.-16mm

5.00

2. Aluminium clamps

2 in number Al

Thickness – 2mm

Dia- 20mm

Width- 15mm

2x25.00

=50

3.

Aluminium plate for

laser-I

2in number

Al

Thickness – 2mm

Length- 70mm

Width- 15mm

2x10.00

=20

4. Aluminium Base for

Laser -II Al

Thickness –2mm

Length- 30

Width- 15

25

Total 100.00


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Fig 3: parts of chassis

3. Outer body

outer body is made out of metal sheet of that provide cosmetic look to LCLA and protect

internal parts. Dimension of outer body (60x90x110) mm3.

Fig 4: Outer surface of the LCLA

Table 3: Specification of the part used in outer body of the LCLA

4. Reflection plates

There are two no. of C shaped reflection plates. The function of it is change the point

projection to line projection of the LASER pointer.

Serial no. Name of part Specification Cost in Rs.

1 Outer body (box)

Height – 115mm

Width-58mm

Length- 115mm

100.00

2 Cosmetic Outer covering

with fitting charges N.A. 100.00

Total 200.00


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Fig 5: Deflection plate

Table 4: Parts, material, dimension and cost of the deflection plate

Serial No. Name of Part Material Dimension Price in Rs.

1. Reflection Plate

(2 in quantity) Stainless steel

Thickness-

Length-36mm

Width-16mm

Radius-500mm

125x2= 250.00

Total 250.00

5. LASER pointers

A LASER pointer or LASER pen is a small handheld device with a power source (usually a

battery) and a LASER diode emitting a very narrow coherent low-powered LASER beam of

visible light, intended to be used to highlight something of interest by illuminating it with a

small bright spot of colored light. Power is restricted in most jurisdictions not to exceed

5 mW. There are two no. of LASER present in this aligner. The color of projection of the

LASER may be red and green for identification of vertical and horizontal LASER

Fig 6: Pointer used in LCLA.

http://en.wikipedia.org/wiki/Laser_diode

http://en.wikipedia.org/wiki/Coherence_%28physics%29

http://en.wikipedia.org/wiki/Laser


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Table 5: parts and cost of laser pointer

6. Battery

Battery of 4.5volt and 1000 mAh may be used. mAh means milli-Amp hours. A milli-Amp is

1/1000th of an Amp, so 1000 mAh is the ability of the battery to deliver 1000 milli-Amps for

one hour or you could say 1-Amp hour.

Table 6: Parts and cost of the battery

Name of Parts No. in use Voltage Dimension Price in Rs.

Battery 1 piece 4.5volt 32x52x4mm 299.00

Total 299.00

Fig 7: Battery used in LCLA

7. Switches: two switch on/off switches for individual LASER.

Table 7: Dimension and cost of Switches

Name of Parts No. in use Type Dimension Price in Rs.

Switches 2 piece On/Off 14x12mm 20x2= 40

Total 40.00

Fig 8: switches

Name of Parts No. in use Material Dimension Price in Rs.

LASER 2 pieces Prefabricated N A 80x2 = 160.00

Total 160.00


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8. Connecting wire

Connecting wire for connecting LASER and battery with Switch for individual LASER. The

battery will also connect with a charging port V3.

Fig 9: Wire in laser aligner

Table 8: Length and dimension of connecting wire

9. Charging indicator

Just a small circuit having a diode, a LED, and a resistance. It connects with the charging

socket. When charging is on this LED glow and indicates charging of the battery.

Table 9: Charging indicator circuit

Serial no. Name of component of circuit Price in Rs

1. Charging indicating circuit with labor charges 80.00

Total 80.00

10. Angle reading plate with angle controller

it present at the backside of the LASER or users side. It provides reading of angle of rotation

of horizontal LASER line from vertical line. It has reading form 00- 360

0.

Table 10: Specification and cost of angle indicator

Name of Parts Specification Dimension Price in Rs.

Angle Measuring plate with

controller

360 degree Diameter 44mm 25.00

Controller N.A. 20.00

Total 45.00

Name of Parts Quantity in use Type Dimension Price in Rs.

Connecting wire ½ meter Ribbon wire 6x.2mm 25.00

Total 25.00


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Fig 10: Angle reading plate

11. Charger

a charger for charging battery of 4.5volt output should be used.

Table 11: cost of charger

Name of Parts No. in use Voltage Price in Rs.

Charger 1 piece 4.5volt 80.00

Fig 11: Charger

Assembling of aligner

Laser pointer was taken and then it opened from its anterior and posterior side & batteries and

front lance was removed. Outer shell of the laser pointer was cut vertically and removed the

laser pointer inside it as shown in fig 13. The push button was removed from it and cut the

spring according to fig 14. Laser wires were solder on its connection according to Fig 15.


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Fig 12: Laser pointer

Fig 13: Laser removed from the shell

Fig 14: Cutting of spring in Laser

Fig 15: Soldering of wire


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The laser was connected with batteries for the checking of function (Fig 16)

Fig 16: Laser connected to batteries

Reflection plate was fixed with the Chassis as shown in fig 17. Laser was attached with

the chassis. (Fig 18)

Fig 17: Reflection plate with Chassis

Fig: 18 Lasers with Chassis

Fig: 19 Second Laser attached with chassis


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Fig 20: Angle controller attached to the Laser

The protector with the body and angle controller with the chassis of adjustable laser was

attached. (Fig 20) Angle controller was rotated and checked for the rotation of adjustable

Laser aligner. (Fig 21).

Fig 21: Checking of rotation in adjustable aligner

Switches and charging point were fixed in the respective channels of the body. (Fig 22)

Fig 22: Switches fixed to the body


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Connection was made as per the fig 23 shown below.

Fig 23: Connection of laser I and II with the circuit

Switches of the laser were tested to check the functionality. Then charger attached with the

charging slot and checked that the indicator was working or not. The leveling tube with its

posterior aspect (user aspect) fixed horizontally. Stand was assembled with the adjustable low

cost aligner. The final device was checked with various clinical trials.

Standardization of aligner: The low cost laser aligner was standardized by following a

plumb line method. A point was marked on the wall by pencil then a plumb line form this

point was drawn. Another point was marked just behind the thread at approximately one

meter of distance from previous point. The plumb line was removed than both points were

checked carefully conforming that these both points were the imaginary vertical line. The

laser was adjusted for coincidence of that line. When both the lasers lines were fixed in

coincidence the aligner was leveled with leveling tube. (The air-bobble should be in center of

tube and static condition) The vertical, horizontal and angular alignment can be possible by

using this low cost alignment device. (Fig 24).

Fig 24: Vertical alignment checked on wall


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Accuracy of the LCLA checked by following plumb bob method, five vertical lines were

drawn at wall by help of Plumb bob. The aligner was placed in front of wall in suitable

distance. Vertical laser was on and coincide this laser line with first line. The leveling tube

was checked for the bubble was in centre and static or not. This Method repeated for five

times and result was consistence in each trial. Similarly the angulations were checked in each

5 degree interval and the result was found satisfactory.

Alignment methods followed by Low cost Laser aligner (LCLA)

The linear and angular relationship between all parts of the prosthesis is called Alignment.

For M-L alignment keep the aligner in front of prosthesis in suitable distance.

Leveled the aligner then switch on the vertical LASER.

This line should replace the plumb line.

Now switch on the horizontal LASER.

Adjust the light beam by moving the instrument according to the desired position.

Now after completing M-L alignment we will move the aligner with stand in side of

prosthesis for A-P alignment.

Repeat the above procedure.

Clinical application of LCLA

The Low cost laser aligner was tested in prosthetic workshop for bench as well as static

alignment of transtibial and transfemoral exoskeletal prosthesis. This alignment device plays

a crucial role during bench alignment the comfort ability of the patient with the prosthesis

totally depends upon the alignment.(Fig 25,26).

Fig 25: Bench alignment in sagittal plane of below knee prosthesis


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Fig 26: Bench alignment in Frontal plane of Transtibial prosthesis

Fig 27: Alignment of prosthesis by LCLA

If any deviation occurs in alignment, it creates discomfort on the stump ultimately patient

discards the prosthesis.

DISCUSSION

Accuracy: The experiment of vertical laser line accuracy parameter, it found that the vertical

laser line matched with the plumb bob traced line. This method repeated five times and the

similar result was found in each time. So this can be predicted that the vertical laser line was

almost accurately vertical. The angular measurement also accurately matched the previously

drawn line by plumb bob. The clinical trial was done in five Trans tibial and three Trans

femoral prosthesis using the low cost laser aligner system and the patients were found

satisfied with this alignment system. The gait was near to normal and they were comfortable

with the prosthesis.


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Cost: The cost of this LCLA was found approximately Rs 1800 – Rs 2200 which was very

affordable for the developing countries.

Total Cost of Low cost Laser Aligner

Serial no. Name of part Cost of part in Rs.

1. Stand 197.00

2. Chassis 100.00

3. Outer body 200.00

4. Reflection plate 250

5. Laser pointer 160.00

6. Battery 299.00

7. Switches 40.00

8. Connecting wire 25.00

9. Charging indicating circuit 80.00

10. Angle measuring plate 45.00

11. Charger 80.00

12 Any other cost 500.00

GRAND TOTAL 1976.00

CONCLUSION

The alignment instrument is a prime importance of the fabrication of orthosis and prosthesis.

Conventional instrument of alignment is visual plumb-bob (plummet). Usually in Lower

Limb Prosthesis Plumb-bob is used for weight bearing line. It helps to check the Anterior-

posterior and Medial-lateral static bench alignment but it needs much experience skill to

handle a plumb-bob for alignment and it does not provide an exact angulations relationship

between socket and pylon. To overcome this accuracy and angulations factor the laser beam

Laser Aligner is introduced. These types of aligner provide accuracy in linear as well as

angular relationship between components of prosthesis but not affordable by most of the

P&O workshop of the under developing countries like India due to its high cost. This LCLA

system was an effort to overcome that cost factor and to provide quality of life to the disable

people. Further more studies are required to standardize this instrument universally.

Limitations of LCLA

LASER pointer may dysfunction during use.

No universal shifting method of LASER installed without shifting the instrument

REFERENCES

1. M. S. ZAHEDI, W. D. SPENCE, S. E. SOLOMONIDIS, J . P. PAUL, Alignment of

lower limb prosthesis, Journal of Rehabilitation Research and Development; 1986; 23(2):

2-19.


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2. University of California (Berkeley), Prosthetic Devices Research Project, [Report to the

Advisory Committee on Artificial Limbs, National Research Council, Functional

considerations in fitting and alignment of the suction socket prosthesis, March 1952.

3. S. Blumentritt, A new biomechanical method for determination of static prosthetic

alignment, Prosthetics and Orthotics International, 1997; 21: 107-11.

4. C.W. Radcliffe, Mechanical Aids for Alignment of Lower-Extremity Prostheses,

Prosthetics and orthotics International, 1977; 1: 20-28.

Documents

LOW COST LASER ALIGNMENT SYSTEM: A NEW APPROCH