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Orthopedic Challenges and Treatments in PWS [2022 CONFERENCE VIDEO]

In this video, Dr. Harold van Bosse and Dr. Nora Wagner discuss orthopedic challenges and treatment in PWS.

In this 2-hour and 2-minute video, Dr. Harold van Bosse, a pediatric orthopedic surgeon at SSM Health/Saint Louis University/Cardinal Glennon Children’s Hospital, and Dr. Nora Wagner, an APTA board certified pediatrics clinical specialist, discuss orthopedic challenges and treatment in PWS. The session includes Q&A from participants in the 2022 FPWR Conference.

Click below to watch the video. If you're short on time, scroll down for timestamps to find the portions you're most interested in.


Presentation Summary With Timestamps

0:00 Dr. Harold van Bosse and Dr. Nora Wagner present Orthopedic Challenges and Treatments in PWS 

0:49 Introduction: Dr. Harold van Bosse

  • Practicing pediatric orthopedic surgery and has come to specialize in treating spinal deformities in very young children with PWS.
  • He seeks the least invasive modalities that will preserve spinal growth, including bracing, spinal casting, and expandable implants to avoid a spinal fusion during childhood.
  • Dr. van Bosse is a member of the Clinical Advisory Board of FPWR 

2:35 Orthopedic Challenges in PWS

2:38 What is Prader-Willi Syndrome?

  • Most common cause of genetic obesity syndrome, first described in 1887
  • 25 years later, the microdeletion of chromosome 15 (Prader-Willi region) was discovered
    • Lacking from father’s chromosome=PWS
    • Lacking from mother’s=Angelmann’s syndrome
    • It is a genetic syndrome but unlikely to “run in the family”
    • Occurs 1 in 10,000 births (very rare)

5:46 Musculo-skeletal issues in PWS

  • Hypotonia
  • Scoliosis
  • Hip dysplasia
  • Flat-footedness

6:02 Development Delays

  • Children with PWS start out very hypotonic, very low toned
  • Moms will sometimes note that even before they were born, babies weren’t moving as much as in prior pregnancies
  • Oftentimes babies are born post-term or by cesarean section because they just didn’t have the energy to birth themselves.
  • In the newborn period, babies with PWS have a poor suckling ability and a weak cry.
  • As they grow, toddlers have poor head control, and may have issues with sitting up.
  • Milestones can take twice as long as typical milestones; if a typical baby is sitting at 6 months, a PWS baby can take up to 12 months.
  • A typical child walks at 12 months; on average a child with PWS walks at 27 months.

7:09 Treatment

  • Bracing is an important part of trying to get kids up and around and give them control of their feet and ankles.
  • Interesting aspect of PWS is that children are weaker centrally than they are in the extremities.
  • If we give them a good stable platform to start walking on, that’s going to get them up sooner. 
  • Mantra at my clinic is I want to get them walking in any way possible and then work on points for style. I don’t care if they have big, clunky braces on if that gets them standing. 
  • If they get more adventuresome and move across the room without holding onto furniture, that’s a big win, and we can get them moving from there.
  • Once they start walking, walking becomes self-rewarding.
  • Children with PWS do better with a different type of brace than kids with cerebral palsy; they need more support.

8:30 Flatfootedness

  • In as many as 40% children with PWS, the heel often rolls to the outside; the outer border of the foot has a concave curve, and the front of the foot is turned outward. 
  • Flatfootedness is caused not just by decreased tone in muscles that hold up the arch but also because babies with PWS tend to be hyper flexible so they can’t rely on their own ligaments to hold things in place.
  • They have to work extra hard to hold things in place, and the foot is in poor position for running and walking. It makes it harder to balance and hard to generate a good push off.
  • Walking becomes inefficient and tiring.
  • Tendon can also become shorter and you get somewhat of a crouched position over time.
  • Flatfootedness delays cruising because once they start cruising they don’t want to let go of furniture; they get fatigued and have something called “high guards” — they walk with their hands up a little bit so they can protect themselves if they fall.
  • Bracing is an effective treatment: 
    • Supra Malleolar Orthosis (SMOs).
    • UCBL, gets the heel underneath the ankle and helps children get around.

13:18 Osteoporosis and PWS

  • Osteoporosis is decreased bone mineral density, not enough calcium in bones.
  • Studies have shown different rates of bone fragility in people with PWS, as high as 45 percent experiencing fractures.
  • Some people with PWS have decreased pain awareness and can walk on fractured bones without anyone realizing it.
  • Growth hormone has made a big improvement, but doctors still see a lot of fractures out there.
  • Research shows that people with PWS have 20% less mineral in their bones compared with typical adults, primarily in the lumbar (lower back), pelvis, and legs. 
  • Treatments: growth hormone and hormone replacement therapy, routine vitamin D and calcium.
  • Staying active is also important because the more active we are, the stronger our bones become.
  • Parents need to stay aware of bone issues because a child might appear to have a minor injury but it could be a fracture. 

16:48 Hip Dysplasia

  • Hip dysplasia means the joint wasn’t formed correctly initially, because babies with PWS aren’t moving much before and after birth.
  • Hip dysplasia can lead to arthritis, so we want to understand that as a child you can have hip dysplasia and show no symptoms but in developing years, teen or college age, they discover it.
  • Congenital hip dislocations do happen.
  • Hip dysplasia is thought to occur in between 8 and 30% of children with PWS, compared to 1% in typically developing children.
  • Prevention is screening and encouraging as much activity as possible to get hips to develop over time.
  • If hips haven’t normalized by 4 years of age, they are in trouble, and may need surgery.  

24:10 Spine Deformities

  • Scoliosis is a side-to side curve in the spine
  • Hyperkyphosis is where you have a very big curve in the upper back.
  • Typical scoliosis in a typically developing child is lordoscoliosis, which means they actually lose their kyphosis.
  • Between 60 and 70% of children with PWS will probably have a curve in the first 4 years; there is a period of quietness between 4 and 8 or 10, or around adolescence.
  • Approximately 50% of children with scoliosis will need to have spine surgery; these surgeries have a high complication rate.
  • Need to watch curves carefully to see if they will progress or require surgery.
  • The reason surgery is sometimes necessary is because a very big curve will compromise the shape of the chest and the space for the lungs. When lungs become less efficient, the heart has trouble pushing blood through.
  • He is a big advocate for doing regular x-rays. 
  • After a certain age, there is always a question of how much obesity plays into this, but there doesn’t seem to be a big difference in terms of body mass and developing a curve.
  • In young children, spinal curves begin before obesity, and it is more likely that curves are due to hypotonia, or inability to hold themselves up well through muscles.
  • Excited to see what data the Global PWS registry yields on this issue.

32:00 Scoliosis Treatments and Prevention 

  • Parents want to help children sit up and play with them, but children with PWS don’t have central strength to hold themselves up, so they tend to slouch. 
  • The worry is that the slouch can kickstart scoliosis.
  • Recommends waiting until the child can pull themselves up to a sitting position, and leaning them back so they are supported.
  • “Tummy time” is important for strengthening the back.
  • Screening should begin once a child is upright and sitting, and continue every 6 months, or more frequently if there is a concern.
  • Regardless of what the back looks like, physical therapy is really important.

35:20 Casting for Scoliosis

  • Casting is an option that used to end at about 3 years, but it has been extended past that.
  • Spinal surgery tends to work better if held off until 7 years, so extending casting can help.
  • Casting is done on a special table under anesthesia. 
    • Under 2 years of age, the  cast is changed every 2-3 months.
    • Over 3 years, the cast is changed every 4 months.
    • Casting is finished either when the orthopedist is satisfied that the curve is small enough or they have reached a plateau.
  • Results from casting in several patients showed that the initial curve, on average was around 44 degrees, and casting reduced it to 17.
  • Did not find many factors that could predict who was going to do better with casting: gender, left or right curve, or age.
  • The biggest difference was the size of the curve. If it was under 50 degrees, they had a 9 times better chance of correcting the curve.

44:46 Bracing for Scoliosis

  • Bracing is for kids who are not eligible for casting because of age or size of curve.
  • Bracing can prevent progression or slow progression, but it cannot reverse.
  • Bracing puts children in better positions; some children have separate daytime and nighttime braces.

47:38 Surgery for Scoliosis

  • The goal of surgeries is to align the spine as best as possible, not just from behind, but also from the side.
  • Surgery holds everything in position with a rod on either side of the spine and uses different things to anchor those rods to the vertebrae.
  • Surgery has a high complication rate in PWS, led by infections. 
  • Most of those infections are a result of skin picking.
  • In his practice, he puts braces on children after surgery to protect incisions. Brace stays on for 3 months.
  • Other risks: Anesthesia, hardware issues.
  • Important to treat children as having PWS primarily, and scoliosis secondarily. 
  • Expandable implants, or magnetic expansion control rods,  help keep up with growth.

53:40 Spinal Fusion Surgery

  • A formal fusion means putting bone graft next to rods, and the body believes it is healing from a fracture.
  • What they are finding in children with PWS is that it becomes harder and harder to lengthen rods, making it harder to link.
  • Fusion has a 5-year lifespan.
  • There is a smaller procedure where they make a small incision at the top and take out the old hardware and thread in new rods underneath skin and muscle.
  • Spinal fusion is for older kids who don’t have a whole lot of growth left to them, where we know the curves are going to be over 50 degrees at maturity.
  • The older the kid is, the easier it is for them to tolerate the emotional aspects.
  • He will keep children in braces as long as possible, as long as the curve stays under 50 degrees.
  • Different ways of doing surgery. 
  • Literature suggests that going between the ribs to get to the front of the spine is a bad idea for people with PWS; they get pneumonia, or infection in the chest.

55:16 Surgery and PWS: Pre-Op

  • Children with PWS need a lot of tests and special considerations, pre-operatively:
    • Pulmonologists
    • Sleep studies to see if they are having trouble with apneas
    • IVs that can stay in longer for additional treatments
    • Strict food protocols
    • Airway management, making sure the breathing tube is in for a safe amount of time
    • Skin picking, preventing them from attacking the incision
    • Managing returning to eating/drinking to prevent air bubbles
    • Making sure that the surgeon doesn’t overcorrect kyphosis so the patient is in a comfortable position.

1:02 Growth Hormone and Scoliosis

  • There have been some questions and differing opinions on whether growth hormone worsens scoliosis.
  • They now believe that growth hormone has many more benefits than drawbacks, and that for every month delay in starting growth hormone, the risk of needing spine surgery goes up 0.7 %.
  • Because scoliosis is growth-related, overall progression is likely to be the same whether you are on growth hormone or not.

1:05  Treating Orthopedic Impairments in PWS

  • Introduction: Dr. Nora Wagner, an APTA board certified pediatrics clinical specialist with certification in International Scoliosis Therapy Program. 

1:07  Physical Characteristics in Patients with PWS

  • Musculoskeletal
    • Sleep disturbances are also common and can contribute to patients with PWS feeling more fatigued.
    • Recurrent respiratory infections
    • Muscle weakness, or hypotonia
    • Balance and risk of fractures
    • Flatfootedness, hip dysplasia, and scoliosis
    • Cardiopulmonary
  • Neurological: delayed motor planning, execution, and balance
  • Integumentary: in cases of morbid obesity, poor ability to relieve pressure points of the body, resulting in pressure sores.

 1:10  Breathing and Postural Control

  • Mary Massery, PT, pioneered the concept of relationship between breathing and postural control.
  • Uses soda pop can analogy.
  • Human trunk is like the can, very thin and flimsy, but it’s functionally strong. You can’t really crush it unless you were to puncture it.
  • When it’s open, it loses strength because it loses the pressure inside.
  • The core, abdominal cavity, pelvic floor, and vocal folds are important in regulating the pressure.
  • When this unit is functioning and strong, we can withstand the forces of gravity.
  • The diaphragm is important for balance and GI motility and helps regulate the ever-changing pressures between the thoracic cavity and the abdominal cavity.
  • When we take a deep breath, our diaphragm comes down. The chest and diaphragm need to work together for the unit to stay nice and strong and combat forces of gravity.
  • PTs can help correct musculoskeletal issues with breathing techniques that create a strong foundation.
  • Activity levels for PWS are important, not only for health implications but for quality of life.

1:22 Development of Chest Wall 0-12 months

  • Typical development
    • Newborns have a triangular chest shape with horizontal ribs, and need to develop muscles for shaping and developing the chest wall.
    • Up to 12 months, the ribs have descended and resemble the mature formation, muscles regulate abdominal and thoracic pressure.
    • The formation is shaped by chest wall muscles and abdominal muscles helping to open and pull ribs downward. Helps to handle gravity in upright positions, and absorbs force and distributes load.

1:24 Consequences of Hypotonia in PWS

  • Hypotonia disrupts breathing mechanics to coordinate with the muscles for postural control.
  • Pressure is lost through weak abs, intercostals (ribs), and impaired chest wall development.
  • Rib cage remains more horizontal and doesn’t fully descend.
  • When trying to be upright, the child has trouble withstanding gravity, resulting in the chest collapsing over the pelvis, kyphotic posturing, and forward head posture.
  • Decreased muscle tone can cause unbalanced forces applied to the skeleton, resulting in excessive kyphosis and/or scoliosis.

1:35 Scoliosis in PWS

  • 3-dimensional deformity of the spine with a high incidence in PWS.
  • Two common curves are C-curves and S-curves.
  • Scoliosis causes inefficient breathing patterns.
  • Prevention and screening are key! Caregivers should look for:
    • Asymmetrical “folds” at the waist
    • Uneven shoulders or hips
    • Altered motor patterns like being able to balance on one leg, asymmetrical jumping, preference for one leg using stairs
    • Different range of motion in shoulders
    • Pull of fabric on clothing

1:41 Therapeutic Treatment Options in Scoliosis

    • Range of motion, stretching arms past 90 degrees, lifting “baby weights” on back
    • Tummy time! Essential for developing core and oblique muscles.
    • Developing muscles that facilitate the descent of the rib cage from horizontal to downward.
    • Infants: scoliosis is often not present until the child is exposed to upright positioning (sitting).
    • Chest facilitation: develops the anterior rib cage, encourages thoracic expansion, and prevents hyper-kyphosis

1:46  Exercise Ideas/Modifications for Play

  • Chest wall mobility
  • Breathing exercises, compressing abdomen to activate diaphragm
  • Diaper exercises
  • Side lying

1:50  Strengthening for Toddler/PreK and Beyond

  • Positioning is key; it’s not only for babies.
  • When starting sitting, hips should be slightly above knees for optimal alignment.
  • Better alignment means better ability to withstand gravity.
  • Visual examples of PWS clients and nephew with drastically improved posture and communication throughout a year.

1:56 External Supports

  • Abdominal binder (use caution when the child is experiencing reflux)
  • TLSO
  • Binding

1:57 Schroth Scoliosis Therapy

  • Developed by Katharine Schroth in Germany.
  • Incorporates bracing, breathing, and positioning.
  • Goals include stabilizing the curve, addressing all three planes, using sensorimotor and angular breathing to achieve muscle symmetry.
  • Typically delivering in 12-week bouts with 1-2 visits per week.
  • Need more research, but she uses it all the time for positioning.

1:59 Aquatic Therapy

  • Delivered in warm temperature water.
  • May be beneficial for providing additional sensory input and help orient the body by partially eliminating gravity.
  • Opportunities to improve range of motion in the trunk and extremities.
  • Because it is easy to move, it encourages repetition for motor learning.
  • Should be added as a complement to other dry-land therapies to address musculoskeletal and bone strengthening.

1:59 Hippotherapy (Horses)

  • Hippotherapy is well known in the PWS community.
  • Cadence and rhythm of a horse is beneficial in addressing core strength, upright alignment, and coordination.
  • Hippotherapy is a multi-disciplinary approach that provides opportunities for OTs, PTs.
  • Creates an environment for physical and cognitive problem-solving.

2:00 Summary

  • Patients with PWS experience multi-system impairments.
  • Hypotonia and weakness contribute to delayed development, including the chest wall and can impair muscles used for breathing.
  • When the supporting muscles don’t support the pressure generated by breathing, patients have increased difficulty in upright positions.
  • Trouble maintaining upright positioning causes asymmetrical loading forces that contribute to scoliosis (spine curves).
  • With modifications to exercise and bracing/casting, these factors can be improved or minimized and improve the multi-system impairments; this enhances mobility and participation in activities—to improve quality of life.

2:02 Q&A

FPWR Enewsletter

Topics: Therapeutic Development

Susan Hedstrom


Susan Hedstrom is the Executive Director for the Foundation for Prader-Willi Research. Passionate about finding treatments for PWS, Susan joined FPWR in 2009 shortly after her son, Jayden, was diagnosed with Prader-Willi Syndrome. Rather than accepting PWS as it has been defined, Susan has chosen to work with a team of pro-active and tireless individuals to accelerate PWS research in order to change the future of PWS. Inspired by her first FPWR conference and the team of researchers that were working to find answers for the syndrome, she joined the FPWR team in 2010 and led the development of the One SMALL Step walk program. Under Susan’s leadership, over $15 million has been raised for PWS related research.