Head Positioning System for Pediatric Patient With Macrocephaly

Head circumference (HC) is a measurement that offers doctors valuable information about the development of the three components of the skull: brain parenchyma, cerebrospinal fluid and bone and connective contents (Fig. 1). Macrocephaly appears when the head circumference of an infant is above 2.5 standard deviations and can be due to multiple causes. Physical examination and warning signs help diagnose serious causes, such as hydrocephalus or megalencephaly with malformations. 

Children with macrocephaly may show balance problems, late development in processes such as walking or speaking, or poor motor coordination. In addition, they might present difficulty staying awake, which is why it is common for them to use wheelchairs for mobility; the latter have positioning systems that are mainly for head support. 

For this reason, it is essential to have a wheelchair with tilting, which allows the angle of the seat to vary with respect to the vertical, such that throughout the day the degrees of tilt can be modified to facilitate head control. Tilting the wheelchair backwards reduces the effort the patient has to make to keep their head upright and offers the support the patient needs. 

Thus, we here show a head support, specially designed for an infant patient with macrocephaly due to hydrocephalus, which is an excessive accumulation of cerebrospinal fluid in the brain. Normally, this fluid protects and cushions the brain, but too much fluid exerts harmful pressure on it. Hydrocephalus can be acquired or congenital; the latter is caused mainly by the presence of spina bifida, aqueductal stenosis or malformations in the brain. Without treatment, up to 6 in 10 people with hydrocephalus will die and those who survive have varying degrees of intellectual, physical and neurological disabilities. 

User profile:

• Age: 5 years old. 
• Gender: Female. 
• Medical Diagnosis: Congenital malformations of the brain. 
• Nosology: Non-communicating hydrocephalus, severe gait pattern deficiency (severe gait impairment); use of the MIGO tilt-assist PCI neurological wheelchair (Fig. 2). 
• Mobility level: Due to severe gait impairment, the user is dependent on the wheelchair for mobility, pushed by the caregiver. She has enough strength in the trunk and neck to move and support her head on her own. 
• Specific needs: Because the commercial wheelchair is designed for users with cerebral palsy, the head supports provided by the wheelchair manufacturer does not meet the user's needs, however, the tilt is functional for the user.

Measurements considered for the prescription of the wheelchair:

• Seat length: 28 cm.
• Calf length: 29 cm.
• Backrest height: 38 cm.
• Trunk width: 20 cm.
• Height of trunk supports: 30 cm.
• Head circumference: 76 cm.
• From the height of the eye to the support: 27 cm.

The comercial wheelchair is equipped with:

• Pelvic and thorax support belts.
• Removable and folding armrests.
• Cushioned armrests.
• Cushioned backrest.
• Adjustable thoracic supports.
• Abductor seat.
• Removable integrated footrest.
• Adjustable headrest.
• Lateral hip cushions.
• Pneumatic rear wheel.
• Adjustable lever brakes.
• 8" front wheel.

• .stl files.
• PLA filament.
• 3D printer.
• 2 steel sheets 1 mm thick (13 cm x 15 cm).
• 8 rivets with grip 3/8” and 1/8” diameter.
• Riveter.
• Center punch.
• 4 M3x20 screws.
• 4 M3 nuts.
• Drill.
• M3 Drill Bit.
• 2 M5x20 screws.
• 2 M5 nuts.
• 5 cm thick foam.
• 1 cm thick foam.
• Glue 5000.
• Flexometer.
• Measuring tape.
• Black cotton fabric.
• Velcro
• Roughing tool.

To assembly the prototype, follow the next steps. 

Print all the .stl files.

Support set

2.1 Join l_head and r_head with glue 5000.

2.2 Bend steel sheets with respect to the curve of the support.

2.3 Glue the front sheet to the inside of the support and wait for it to dry.

2.4 Drill the holes from the back of the support.

2.5 Glue the back sheet to the back of the support and wait for it to dry.

2.6 Drill the holes using the front part as a guide.

2.7 Rivet with the mentioned materials.

Hinge assembly

2.8 Place both hinges at the same height, considering 2 cm from the base of the support to the edge indicated in Fig. 3.

2.9 Use a central punch to mark the four points to be drilled.

2.10 Drill the four holes.

2.11 Screw and place the nuts to fix the hinges.

Lateral assembly

2.12 The pivot of the side pieces is inserted into the hinges (Same procedure on both sides).

2. 13 The M5 screws are placed in the pivot holes.

Foam for the support

3.1 From both foams, cut out a rectangle 15 cm wide and 29 cm long (Fig. 4).

3.2 On the basis of the rectangles cut out the trapezoid shape using the support as a guide.

3.3 Rough out the foam trapezoid with a thickness of 5 cm to obtain a thickness of 3 cm at the top and 4 cm at the bottom.

3.4 Glue the 1 cm thick trapezoid to the previous piece with Resistol 5000.

Lateral foams

3.5 Cut out the perimeter of the l_lateral and r_lateral with both foams.

3.6 Roughen both figures to reach a thickness of 3 cm on the upper part and 4 cm on the lower part.

3.7 Glue with Resistol 5000 the 1 cm thick trapezoid to the previous piece.

4.1 Make the pattern on the fabric based on the support foam (Fig. 5) and the lateral foams (Fig. 6), adding an extra inch to the outline.

4.2 Draw rectangles 6 cm high (the length does not matter) and cut them out (Fig. 7).

4.3 Sew the fabric to make a cover for the support foam and one for each lateral foam (Fig. 8).

4.4 At the bottom of the cover sew a Velcro strip on each end (Fig. 9).

4.5 Place the cover on each element.

If you have any questions or want to share your results, contact us at 191858@iberopuebla.mx