Prader-Willi Syndrome (PWS)

Prader-Willi syndrome (PWS) is a rare, complex, neuroendocrine disorder characterized by severe hypotonia and feeding problems during infancy followed by hyperphagia and subsequent morbid obesity in early childhood.1

Several clinical features of PWS may require surgical interventions at different phases of the disorder.2

Feeding Difficulties

Poor suck reflex in neonates with PWS results in feeding difficulties, poor growth, and poor strength, and it may lead to failure to thrive during infancy.1 Placement of a feeding tube may be required to ensure adequate nutrition during this phase.3 

Read more about PWS diet and nutrition

Feeding tube placement for neonates with PWS is usually short term, lasting between 6 and 8 weeks. In cases of short-term tube feeding, placement of a nasogastric tube is typically recommended; however, surgical placement of a gastric feeding tube (“G tube”) may be recommended for infants with PWS who require supplemental feeding for more than 2 to 3 months and who demonstrate evidence of silent aspiration.3


Hypogonadism, infertility, and delayed puberty are common clinical findings among both male and female patients with PWS. Additionally, 86% to 100% of male patients with PWS demonstrate cryptorchidism, characterized by a lack of testicular descent.4 

Bilateral or unilateral surgical correction of cryptorchidism via orchidopexy is required for most male patients with PWS (approximately 81%). A 2-stage Fowler-Stephens orchidopexy is rarely required. In a long-term follow-up study, around 40% of male patients with PWS who underwent orchidopexy demonstrated normal-sized testes palpable in the scrotum. A smaller percentage of male patients (approximately 17.5%) with PWS-related cryptorchidism required repeat orchidopexy.4 

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One of the musculoskeletal complications of PWS is scoliosis, in which truncal hypotonia results in the abnormal C-shaped curvature of the spine. This complication requires affected children to be evaluated by an orthopedist familiar with PWS who has expertise in treating scoliosis.5 

Most children with PWS who develop scoliosis are successfully treated with conservative therapies, including physical therapy, casting in children under 3 years of age, and bracing with a thoracic-lumbar-sacral orthosis (TLSO) for 16 to 20 hours each day in children over 3 years of age. The use of TLSO bracing decreases as the child reaches skeletal maturity.5

Spinal fusion surgery is required for cases of severe spinal curvature exceeding 40 to 50 degrees, but care must be taken if children under 10 years of age need surgical intervention since it can restrict further growth of the spine and chest. Expandable implants and newer tethering procedures allow for continued bone growth and preservation of spinal motion; however, definitive spinal fusions may be required if these methods prove unsuccessful at preventing the progression of scoliosis.5

It must be noted that children with PWS demonstrate higher rates of surgical complications from spinal fusions (especially neurological complications) than the general population.6,7 Major complications that have been reported in individuals with PWS undergoing scoliosis surgery include severe kyphosis above the level of the spinal fusion, deep infections, transient paraplegia, pseudoarthrosis, and delayed wound healing. Those with severe kyphosis require reoperation, with most resulting in permanent spinal cord injuries.6 

Endocrine abnormalities resulting in osteopenia in PWS may increase the rate of intraoperative cerebrospinal fluid leaks due to pedicle wall breaches in patients undergoing spinal fusions for scoliosis. Osteopenia may also contribute to high rates of implant failure in those with PWS.7

Due to the significantly higher risk of intraoperative and postoperative complications in individuals with PWS, surgical intervention for patients with scoliosis must be undertaken with special caution.7 

Read more about PWS complications

Hip Dysplasia

Around 30% of patients with PWS exhibit hip dysplasia. Recommendations for early diagnosis and intervention of the condition include ultrasound screening for all infants with PWS at 6 weeks of age and radiographic studies at 1, 2, 5, 10, and 15 years of age. Treatments for individuals with PWS who have hip dysplasia include the Pavlik harness, closed reduction, open reduction, and other surgical interventions for the affected hips.8 

Early interventions are aimed at the prevention of progressive and early wear and tear of the lower extremity joints, which might necessitate total hip or knee arthroplasties at young ages in this population.9 

There are conflicting opinions on the best course of action to treat hip dysplasia in children with PWS. One train of thought suggests that a lack of early intervention for hip dysplasia may result in future arthralgia and arthritis that requires total hip arthroplasty.9

Another train of thought suggests that restricting movement with bracing or casting, including the use of the Pavlik harness, in the early years of the condition might further exacerbate the delayed motor development that is already present in children with PWS. Unrestricted movement and strengthening may allow self-correction of hip dysplasia without the need for intervention.9 

Data from the National Inpatient Sample of Healthcare Cost and Utilization Project from 2004 to 2014 indicate that individuals with PWS undergo total hip or knee arthroplasties at lower relative rates than the general population, suggesting less of a need for aggressive treatment of hip dysplasia in this patient population. However, these findings did not differentiate between the percentage of patients with PWS who underwent these joint replacements due to concomitant hip dysplasia vs those without hip dysplasia. And it was noted that patients with PWS undertook these surgeries at younger ages than members of the general population.9

Read more about PWS risk factors


Biliopancreatic diversion and gastric bypass surgery in this population are not effective for weight loss or long-term management of obesity.2,10 Bariatric procedures for weight management have demonstrated poor results in patients with PWS compared to individuals without PWS who are obese.10

Obstructive Sleep Apnea

Tonsillectomy, adenoidectomy, and tracheostomy placement are surgical interventions that may be required to treat obstructive sleep apnea in individuals with PWS.2

Emergency Surgical Procedures

Higher pain thresholds and a decreased ability to vomit in individuals with PWS may result in the development of life-threatening abdominal complications, including acute gastric dilation with the risk of progression to necrosis or gastric rupture and the late presentation of appendicitis and cholecystitis. All of these abdominal complications may require immediate surgical intervention.2

Read more about PWS prognosis


  1. Fermin Gutierrez MA, Mendez MD. Prader-Willi syndrome. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2023. Updated January 31, 2023. Accessed July 29, 2023.
  2. Scheimann A. Prader-Willi syndrome treatment & management: surgical care. Medscape. Updated August 27, 2021. Accessed July 29, 2023.
  3. G tube vs NG tube in Prader-Willi syndrome. Prader-Willi Syndrome Association USA. Accessed July 29, 2023.
  4. Pacilli M, Heloury Y, O’Brien M, Lionti T, Rowell M, Hutson J. Orchidopexy in children with Prader-Willi syndrome: results of a long-term follow-up study. J Pediatr Urol. 2018;14(1):63.e1-63.e6. doi:10.1016/j.jpurol.2017.10.003
  5. Prader-Willi syndrome. Scoliosis & Spine Associates. Accessed July 29, 2023. 
  6. Accadbled F, Odent T, Moine A, et al. Complications of scoliosis surgery in Prader-Willi syndrome. Spine (Phila Pa 1976). 2008;33(4):394-401. doi:10.1097/BRS.0b013e318163fa24
  7. Winsauer AG, Thornberg DC, Rodriguez SM, Poppino KF, Ramo BA. Angelman and Prader-Willi syndromes: sister imprinting disorders with high complication rates following spinal deformity surgery. Orthopedics. 2023;46(4):e223-e229. doi:10.3928/01477447-20230207-07
  8. Trizno AA, Jones AS, Carry PM, Georgopoulos G. The prevalence and treatment of hip dysplasia in Prader-Willi syndrome (PWS). J Pediatr Orthop. 2018;38(3):e151-e156. doi:10.1097/BPO.0000000000001118
  9. Strong T. Hip dysplasia in babies with PWS may not need aggressive treatment. Foundation for Prader-Willi Research. July 22, 2020. Accessed July 29, 2023.
  10. Scheimann AO, Butler MG, Gourash L, Cuffari C, Klish W. Critical analysis of bariatric procedures in Prader-Willi syndrome. J Pediatr Gastroenterol Nutr. 2008;46(1):80-83. doi:10.1097/01.mpg.0000304458.30294.31

Reviewed by Hasan Avcu, MD, on 7/30/2023.