This presentation was published in January 2018 during the National Conference of OPAI. This presentation includes a research work for a 15 yr old fixed scoliotic patient to cure and atleast prevent from further progression of the curve by providing him a customised molded seat acc to the nature of his deformity . We name this as ESMS.

1. Priyanka Rawat, Rohan Gupta
BPO, FINAL YEAR
Pandit Deendayal Upadhyaya National Institute for
Persons with Physical Disabilities [Divyangjan]

2. WHAT IS SCOLIOSIS?
 Scoliosis is a medical condition in which a person’s spine is
curved from side to side.
 Lateral curvature of the spine>10 deg accompanied by
vertebral rotation.
 Scoliosis is defined as the lateral curvature of the spine
with torsion of the spine and chest as well as disturbance of
the sagital profile.

3. STRUCTURAL NON-STRUCTURAL
CLASSIFICATION
Postural
Compensatory
Sciatic
Idiopathic
Congenital
Paralytic
Others

4. CAUSES OF THE SCOLIOSIS
Congenital
• Caused by
bone
abnormality
present at
birth
Neuromu
scular
• result of
abnormal
muscles
or nerves
Degenrative
• Result from
traumatic injury,
bone collapse,
osteoporosis
• Adult scoliosis
after 65 years
Idiopathic
Most common
type& no specific
unidentified
cause.Types:
infantile,
juvinile,
adolescent,adult

5. PATIENT DETAILS
•Aman gupta,15 years old male adolescent suffering from
congenital type of scoliosis and that to of rigid.
•Due to the lack of the knowledge about the medical
condition in the family, the patient did not get the correct
treatment at the right time.
•The deformity got increased by passing days due to the
continuous improper sitting and neglegence of the proper
need of sitting system.
•Present condition is that the subject has
:-rigid double scoliosis
:-cobb’s angle>90deg
:-FUSION OF C4,C5.C6 Vertebrae.
:-pelvic elevation on the left side
•The patient and his family decided to adopt an
conservative method of treatment rather than the surgical.

6. TOTAL SITTING TIME IN A DAY
25%
34%
13%
8%
8%
4% 8%
time distribution
school time - 6 hours
sleeping time - 8 hours
ADL activities - 3 hours
home sitting - 2 hours
leisure time - 2 hours
commuting time - 1 hour
study time - 2 hours

7.  Source :- parents and the subject
Other than sleeping the maximum time of the subject was spent
in sitting.
 School time ----------------------------------------------------- 25%
 Home sitting ---------------------------------------------------- 8%
 Studying time----------------------------------------------------- 8%
 Commuting time ( sits on E-bike) -----------------------------4%
 Total sitting time---------------------------------------------- 69%
 ACCORGING TO OUR DATA THE SUBJECTS’S MORE THAN
HALF OF THE TIME WAS SPENT ON SITTING IN A WHOLE
DAY ACTIVITY ANALYSIS.

8. SCHOOL VISIT TO EVALUATE THE SITTING
 The school benches were of shorter height.
 Due to the shorter height of the bench the
subject’s lower extremities are being flexed in
the whole period.
 Due to this the subject has to lean forward and
bound to take support from the writing plate
with help of this elbow limiting him from doing
written work and causes pain in the elbows.
 The eye-hand coordination was getting
hampered as the subject’s whole concentration
was on getting the support from the bench.
 The thorax region along with the neck and head
were leaning forward causing him discomfort in
during sitting school time.

9. What is an ESMS
 Derived from two words:
 “nomoi” means natural laws
 “ergon” means work
 So, ESMS is a seat which functions on the natural laws in
the workplace & helps :-

 Sitting is a body position in which the weight of the body
is transferred to a supporting area mainly by the ischial
tuberosities of the pelvis and their surrounding soft tissue.
Maintaining
posture
Reduce
fatigue
Prevents
further
deformity
Prevents
pressure
sores

10.  Purpose - to remove weight from the feet and maintain a
stable posture so muscles not directly involved with the
work can relax and comfort.
 Posture - the relative orientation of parts of the body in
space.
 Best Posture - imposes the least postural stress. Muscles
must do work to counteract the effects of gravity and other
forces as the body stands or moves through space.
 Postural Strain - adverse consequences of more than a
few minutes of postural stress.

11. ESMS Design
PP sheet molded base provides anatomically contoured
firm base
Different layers of cushioning to accommodate heat
dissipation, provide stability
Fixation on the chair via screws and nuts to facilitates
adjustability

12. Biomechanics of the ESMS
Seat Design Criteria
 Seat Height
 Traditional Criterion - Seat height should be adjusted to support a
knee angle of 90-degrees to prevent leg swelling. However 75% of
leg swelling may be due to low leg muscle activity rather than chair.
 Minimum Height - should be 15" (38cm) which designs to the 5th
percentile of women with 1" heels. The seat should adjust 9" (23cm).
 Fixed Height - should be about 17" (43cm). This is a compromise. A
chair that is too high leads to increased pressure at the popliteal
fold (underside of knees), decreasing blood circulation and
increasing pressure on the nerve. A chair that is too low increases
weight on the ischial tuberosities.

13. Seat pan
 Seat Depth - recommended is 16.5" for fixed seats and 14-18.5" for
adjustable seats. If the seat depth is greater than the buttock-
popliteal length (fifth percentile woman is at 17") then the user
won't be able to use the backrest.
 Seat Pan Contours - Half body weight is supported by an 8% area
under the "seat bones" (ischial tuberosities). If the seat is hard and
flat the pressures can be 85-100 p.s.i. Seat contouring and
cushioning can be used to distribute pressure over a larger area and
rotate the pelvis forward the promote better posture.
 Seat Cushioning - recommended thickness at 1.5-2". Cushion
should be firmer in back and thicker while less firm and thinner at
front. Too much cushioning can cause the body to sink into a chair
constraining movement. A soft chair may be comfortable at first,
but as the body sinks blood circulation lowers, skin temperature
rises in affected areas, and compression under thighs increases.
These factors combine to increase discomfort.

14. Fabrication of the seat
NEGATIVE CAST
 The POP cast was taken in the position of
90deg lying positions.
 The shoulder and pelvis were stabilize
during the casting.
 The pressure sensitive areas and the bony
prominences were marked
 The cast was taken in a slab form.

15. REINFORCEMENT
• Two aluminum bars were cut and bend in [L]
shape and were placed inside the negative cast
so as to provide the strength to the cast.
• The flaps of POP bandages were placed at the
anterior and proximal section so as to retain the
POP mixture.
POSITIVE MOLD
• The POP mixture was added to the negative so
as to gain a positive mold.
• Markings were highlighted.
Aluminum
bars

16. MODIFICATION
• Thick POP mixture was added over the left
side to equalize the level of the thigh.
• The mixture was also added at the A,B,C,D,E
sections of the mold.
• This increase in material will protect the bony
areas as these areas will be covered with the
cushioning material later on.
THERMOFORMING
• The polypropylene [PP] sheet of 5mm was cut
according to the measurements of the
modified positive mold.
• As the pp sheet is durable, light weight,
matches the contour, cost effective; so we
chosen it.
A B
C D E

17.  Then the stockinette of 6 inches was
placed over it& placed inside the oven at
the temp.of 25o deg for 5 to 1o minutes
and drapped over the mold.
 A dummy was prepared out of the POP
to apply the pressure over the thigh
region during the thermoforming.
 Then the Polypropylene base was ready.
DUMMY
PRESSURE

18. TRIMMING OF THE BASE
• The proximal section was trimmed 2inches
below the axillary level so as to avoid any
nerve compression or any other discomfort.
• The laterally the curve matches to the
curvature of the subject’s body.
• Distally, it covers 2/3rd of the portion of the
thigh.
Before trimming
After trimming

19. TRIAL WITH SUBJECT
• The subject was made to sit on the base of the PP sheet.
 It was pinching the subject at the axillary level so we
trimmed it over there and slightly at the lateral aspect of
the right side.

20. CUSHIONING COMPOSITION
BASE LAYER: PE FOAM
Closed cell foam, Durable, light weight, non-dusting, non-toxic,
odourless.
MIDDLE LAYER: PU FOAM [reticulated foam]
Open cell foam, Provides cushioning to the bony structures.
TOP LAYER : Fabric
Elastic synthetic fiber, combination of polyester & polyurethane[cotton
also], skin friendly, dries quickly

21. MATERIALS USED CUSHIONING

22.  Seat Cushioning - recommended thickness at 1.5-2". Cushion
should be firmer in back and thicker while less firm and
thinner at front. Too much cushioning can cause the body to
sink into a chair constraining movement. A soft chair may be
comfortable at first, but as the body sinks blood circulation
lowers, skin temperature rises in affected areas, and
compression under thighs increases. These factors combine to
increase discomfort.
 Cushion Compressibility - Compressibility is termed
indentation load deflection (ILD) or indentation force
deflections (IFD). An ideal combination is a soft top layer (25%
ILD) over a firm bottom layer (65% ILD). Increased ratios
between the two, greater than 2.6, leads to better quality
support.

23.  Seat Width - around 20 - 22" to accommodate clothed persons. If seat has
armrests then elbow to elbow breadth may be more relevant.
 Seat Angle - Positive seat angle helps user to maintain good contact with
backrest. For most purposes a 5 - 10 angle is recommended.
 Armrests- give additional postural support and aid in standing up
and sitting down. Armrests should be padded and engage the fleshy
part of the forearm. They should not engage the bony parts of the
elbow where sensitive ulnar nerve is close to the surface so a gap of
approximately 4" between the armrest and seat back is recommended.
Cantilevered elbow rests should be 8-10" above the seat surface height.
Armrests should be at least 17.2" apart to exceed thigh breadth of 95th
percentile females. Finally, armrests shouldn't limit chair access if it is
to be used at a table.
 Backrest-
Height - Higher backrests give better trunk weight support.
Medium-level backrest - gives full shoulder support (e.g. car seat, office chair)
and may need to be about 26" high to accommodate the 95th percentile man.

24. COSMESIS OF SEAT
 VINYL SHEET of black color is
pasted over the POLYPROPYLENE
base outer side by stretching it with
the help of the heat gun to make it
ore cosmetically appealing.
 Inside the POLYPROPYLENE base,
black color oil paint was applied to
make it more resistant to the
environmental hazards.

25. DEATACHABLE MECHANISM
 The velcros were pasted over the PP base and the
cushioning.
 The hard part was pasted over the cushioning part.
 The soft part was pasted over the PP base.
 PURPOSE:-
 This will facilitate the de-attachable mechanism
of the seat.
 Thereby making it cleanable with mild soap water.

26. FINALISED MOLDED SEAT WITH CUSHION

27. FINAL TRIAL WITH ESMS
 The backrest and seat pan were attached to the PP seat with the help of
the nut and bolt and trial was done with the subject.
 The seat should be properly contouring the anatomy of the subject &
providing him the utmost comfort.
 Lap board was attached to the chair to facilitate comfortable reading,
writing etc.
 Sitting to standing and standing to
sitting were easily done.
• All the functions were well achieved.

28. ADVANTAGES OF THE ESMS
 ESMS accommodates the pelvic difference and help in
maintaining a near to normal sitting posture.
 It helps to improve the eye- hand co-ordination of the
subject.
 It also helps in improving respiration of the subject to so
extent.
 It matches the contours of the subject’s body and provides
comfort.
 It is also very cost effective.
 Less cumbersomeness of the ESMS makes it more easy to
use and fabricate.
 Its de-attachable mechanism makes it cleanable.

29. FUTURE DEVELOPMENTS
 This cost effective sitting device can be
made available to rest all the person
suffering with these kind of disability in
various clinical setup.
 Sitting devices can be customized in larger
scale.
 Such other devices can be researched
further.

30. Thank you