Bone Health in Adults With Prader-Willi Syndrome: Clinical Recommendations Based on a Multicenter Cohort Study.

CONTEXT: Prader-Willi syndrome (PWS) is a rare complex genetic syndrome, characterized by delayed psychomotor development, hypotonia, and hyperphagia. Hormone deficiencies such as hypogonadism, hypothyroidism, and growth hormone deficiency are common. The combination of hypotonia, low physical activity, and hypogonadism might lead to a decrease in bone mass and increase in fracture risk. Moreover, one would expect an increased risk of scoliosis due to hypotonia and low physical activity. OBJECTIVE: To study the prevalence and risk factors for skeletal problems (reduced bone mineral density, fractures, and scoliosis) in adults with PWS. METHODS: We retrospectively collected patient characteristics, medical history, medication, biochemical measurements, dual-energy X-ray absorptiometry scans, and spinal X-rays and reviewed the current literature. RESULTS: We included 354 adults with PWS (median age 31 years; 43% males), of whom 51 (14%) had osteoporosis (T-score below -2.5) and 143 (54%) had osteopenia (T-score -1 to -2.5). The most prevalent modifiable risk factors for osteoporosis were hypogonadism, insufficient dairy intake, sedentary lifestyle, and corticosteroid use. Male sex was associated with osteoporosis (P = .005). Growth hormone treatment was not associated with osteoporosis. A history of vertebral fractures was present in 10 (3%) and nonvertebral fractures in 59 (17%). Scoliosis was present in 263 (80%), but no modifiable risk factors were identified. CONCLUSION: Besides scoliosis, osteoporosis is common in adults with PWS. Based on the literature and the risk factors for osteoporosis found in our cohort, we provide practical clinical recommendations to avoid skeletal complications in these vulnerable patients.

No added value of 2-year radiographic follow-up of fusion surgery for adolescent idiopathic scoliosis.

PURPOSE: For fusion surgery in adolescent idiopathic scoliosis (AIS) consensus exists that a 2-year radiographic follow-up assessment is needed. This standard lacks empirical evidence. The purpose of this study was to investigate the radiographic follow-up after corrective surgery in AIS, from pre-until 2 years postoperative. METHODS: In this historical cohort study, 63 patients surgically treated for AIS, age ≤ 25 years, with 2-year radiographic follow-up, were enrolled. The primary outcome measure was the major Cobb angle. Secondary outcomes were coronal and sagittal spino-pelvic parameters, including proximal junction kyphosis (PJK) and distal adding-on. Change over time was analyzed using a repeated measures ANOVA. RESULTS: The major curve Cobb angle showed a statistically significant change for pre- to 1 year postoperative, but not for 1- to 2-year follow-up. Seven out of 63 patients did show a change exceeding the error of measurement (5°) from 1- to 2-year follow-up (range -8° to +7°), of whom 2 patients showed curve progression and 5 showed improvement. PJK or distal adding-on was not observed. CONCLUSIONS: No statistically significant changes in major curve Cobb angle were found during postsurgical follow-up, or in adjacent non-fused segments. The findings of this study are not supportive for routine radiographs 2 years after fusion surgery in AIS patients.

Sudden proximal spinal dislocation with complete spinal cord injury 1 week after spinal fusion in a child with Prader-Willi syndrome: a case report.

STUDY DESIGN: Case report. OBJECTIVE: To describe a sudden spinal cord injury in a girl with Prader-Willi syndrome (PWS) 1 week after posterior T2-L3 fusion. SUMMARY OF BACKGROUND DATA: PWS is a genetic disorder characterized by several features including growth deficiency, hypotonia, obesity, and spinal deformities. In PWS patients the prevalence of scoliosis and of kyphosis is reported to be 15% to 86% and 8% to 40%, respectively. Operative treatment carries specific and serious risks in these patients. METHODS: A 13-year-old girl with PWS underwent a ventral release and a posterior spinal fusion for a scoliosis with hyperkyphosis of the thoracic spine. Preoperatively, she had no osteopenia or obesity. Posterior instrumentation consisted of fixation with pedicle screws, proximally assisted by a bilateral transverse hook to prevent junctional hyperkyphosis. RESULTS: Postoperative recovery was initially uneventful; however, 1 week after operation the patient suddenly suffered a complete spinal cord lesion at level T4. This was due to myelum compression with a spinal dislocation cranial to the fusion level, and subsequent proximal hook failure. The patient underwent immediate removal of the transverse hooks, an extension of the fusion to T1, and a laminectomy at T2. Eighteen months after the event she was still paraplegic. CONCLUSION: This report describes a sudden and complete spinal cord lesion 1 week after spinal fusion in a child with PWS. Although such an event is often attributed to osteopenia, this was not proven in this case. To our knowledge, this is the first report to describe this event developing so soon and so suddenly after primary surgery. This case report confirms that spinal surgery in patients with PWS carries an increased risk of junctional hyperkyphosis and pullout of hardware.

Randomized controlled trial to investigate the effects of growth hormone treatment on scoliosis in children with Prader-Willi syndrome.

CONTEXT: The prevalence of scoliosis in children with Prader-Willi syndrome (PWS) is 30-80%, depending on age. Although reports about effects of GH treatment on scoliosis in children with PWS are limited, scoliosis is generally considered a contraindication for GH treatment. OBJECTIVE: The aim was to study the effects of GH treatment on the onset of scoliosis and curve progression in children with PWS. DESIGN: We conducted a multicenter, randomized, controlled GH study in infants and prepubertal and pubertal children. Infants and prepubertal children were randomized into a GH-treated group (1.0 mg/m(2) . d) and a control group for 1 and 2 yr, respectively. Pubertal children were randomized to receive somatropin 1.0 or 1.5 mg/m(2) . d. Yearly, x-rays of the spine were taken, and height, weight, truncal lean body mass (with dual energy x-ray absorptiometry), and IGF-I were measured. PATIENTS: A total of 91 children with PWS (median age, 4.7 yr; interquartile range, 2.1-7.4) participated in the study. MAIN OUTCOME MEASURES: We measured the onset of scoliosis (Cobb >10 degrees ) and scoliotic curve progression. RESULTS: GH-treated children had similar onset of scoliosis and curve progression as randomized controls (P = 0.27-0.79 and P = 0.18-0.98, respectively). GH treatment, IGF-I sd score (SDS), and catch-up growth had no adverse effect on the onset of scoliosis or curve progression, even after adjustment for confounders. Height SDS, truncal lean body mass, and IGF-I SDS were significantly higher in GH-treated children than in randomized controls. At baseline, a higher IGF-I SDS was associated with a lower severity of scoliosis. CONCLUSIONS: Scoliosis should no longer be considered a contraindication for GH treatment in children with PWS.

A comparison in adolescents of composite auditory evoked potential index and bispectral index during propofol-remifentanil anesthesia for scoliosis surgery with intraoperative wake-up test.

BACKGROUND: The electroencephalogram-derived Bispectral Index (BIS), and the composite A-line ARX index (cAAI), derived from the electroencephalogram and auditory evoked potentials, have been promoted as anesthesia depth monitors. Using an intraoperative wake-up test, we compared the performance of both indices in distinguishing different hypnotic states, as evaluated by the University of Michigan Sedation Scale, in children and adolescents during propofol-remifentanil anesthesia for scoliosis surgery. Postoperative explicit recall was also evaluated. METHODS: Twenty patients (aged 10-20 yr) were enrolled. Prediction probabilities were calculated for induction, wake-up test, and emergence. BIS and cAAI were compared at the start of the wake-up test, at purposeful movement to command, and after the patient was reanesthetized. During the wake-up test, patients were instructed to remember a color, and were then interviewed for explicit recall. RESULTS: Prediction probabilities of BIS and cAAI for induction were 0.82 and 0.63 (P < 0.001), for the wake-up test, 0.78 and 0.79 (P < 0.001), and 0.74 and 0.78 for emergence (P < 0.001). During the wake-up test, a significant increase in mean BIS and cAAI (P < 0.05) was demonstrated at purposeful movement, followed by a significant decline after reintroduction of anesthesia. CONCLUSIONS: During induction, BIS performed better than cAAI. Although cAAI was statistically a better discriminator for the level of consciousness during the wake-up test and emergence, these differences do not appear to be clinically meaningful. Both indices increased during the wake-up test, indicating a higher level of consciousness. No explicit recall was demonstrated.

Vacuum-assisted wound closure of deep infections after instrumented spinal fusion in six children with neuromuscular scoliosis.

BACKGROUND CONTEXT: The rate of infection after spinal fusion in neuromuscular scoliosis is reported to range from 4% to 20%. Infection persists in about 50% after traditional treatment including debridement and closure. Instrumentation removal is necessary in up to 28%. PURPOSE: To analyze the outcome of vacuum-assisted wound closure (VAC) in combination with antibiotics for the treatment of deep wound infection after instrumented spinal fusion in pediatric neuromuscular scoliosis. STUDY DESIGN: Six prospective consecutive neuromuscular patients with scoliosis. PATIENT SAMPLE: Between 2001 and 2005, six consecutive pediatric patients (average age, 12.6 years) with neuromuscular scoliosis with a postoperative deep wound infection after instrumented spinal fusion were included in the study. OUTCOME MEASURES: Measurement of the duration of wound closure and infection parameters during treatment. METHODS: The patients were treated with a VAC system in combination with antibiotics. RESULTS: Wound closure averaged 3 months. Infection parameters were normalized within 6 weeks. Removal of the instrumentation was not necessary in any patient, and there were no signs of infection at follow-up ranging from 9 to 42 months. CONCLUSION: The VAC system, in combination with antibiotic therapy, seems to be a useful method for treatment of deep wound infections after spinal fusion in pediatric neuromuscular scoliosis. It may prevent removal of the instrumentation and multiple surgery for irrigation and closure of the wound.