Complications of scoliosis surgery in Prader-Willi syndrome

Orthopedic manifestations in children with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a rare genetic disease often associated with bone problems, mainly scoliosis and hip dysplasia (HD). This study aimed to analyze the clinical characteristics of orthopedic deformities in patients with PWS.

METHODS

A retrospective study was conducted on 175 patients up to March 2023. The Cobb angle(CA) of the spine, the alpha angle of the hip joint, and the acetabular index (AI) were measured. This study aimed to evaluate the relationship between demographic parameters and bone deformities.

RESULTS

Scoliosis was found in 66 patients (43.7%), including 52 (78.8%) with mild scoliosis, 10 (15.2%) with moderate scoliosis, and 4 (6.1%) with severe scoliosis. Only seven patients received orthopedic treatment (10.6%). The median age of scoliosis was 4.5 years old, and the prevalence of scoliosis increased rapidly at the age of 5 years and adolescence. The mean CA in this study increased gradually with age. HD was found in 47 patients (38.2%), and 6 patients received orthopedic treatment (12.7%). The median age at HD was 1.8 years old. The mean AI of the study population decreased with age. The prevalence of HD treated with recombinant human growth hormone (rhGH) was low. No significant differences were observed in sex, genotype, body mass index (BMI), obesity rate, or onset of scoliosis and HD.

CONCLUSION

The prevalence of scoliosis and HD was higher in patients with PWS. The onset age and developmental trends of the different skeletal malformations were different. Early diagnosis and treatment are important for the prognosis and treatment of orthopedic diseases in patients with PWS.

Angelman and Prader-Willi Syndromes: Sister Imprinting Disorders With High Complication Rates Following Spinal Deformity Surgery

We sought to examine the modern surgical treatment of spinal deformity associated with sister imprinting disorders, Prader-Willi syndrome (PWS) and Angelman syndrome (AS), with emphasis on the specific complications encountered in these patient populations. Fifteen patients with PWS and 5 patients with AS who underwent surgical intervention for spinal deformity between 2000 and 2018 were identified. Postoperative complications were classified using the modified Clavien-Dindo-Sink (CDS) system and further categorized into specific subtypes including excessive drainage, dehiscence, implant failure, infection, and delayed wound healing. Perioperative and final follow-up radiographic data were analyzed. Mean age at surgery was 12.9 years (range, 4-21 years) with mean follow-up of 46.1 months (range, 1-145 months). There were postoperative complications in 17 patients (85%). Ten major complications (CDS ≥ 3) occurred in 9 patients (45%). These included 5 infections requiring reoperation, 1 seroma requiring drainage, 2 severe cervical-thoracic deformities requiring reoperation, 1 implant failure requiring reoperation, and 1 death secondary to fungal sepsis and thromboembolic disease. Eight additional patients (40%) had minor complications (CDS 1 or 2). Eight intraoperative complications occurred in 5 patients (25%), including loss of neuromonitoring signals and cerebrospinal fluid leaks. Surgical intervention for scoliosis in PWS and AS continues to have high complication rates secondary to medical and behavioral comorbidities found in these patient populations. The exact etiology of the high complication rates encountered cannot be definitively stated, but both syndromes frequently present with a number of unique features that may predispose patients to develop surgical complications. [Orthopedics. 2023;46(4):e223-e229.].

Delayed postoperative cervical spinal cord ischemic lesion after a thoracolumbar fusion for syndromic scoliosis: a case report and systematic review of the literature

INTRODUCTION

We report a case and a literature review of delayed postoperative cervical spinal cord injury after thoraco-lumbar spine surgery.

CASE REPORT

A 13-year-old Prader-Willi Syndrome female was treated by a T3-L5 posterior spine fusion for progressive scoliosis. Intraoperative neuromonitoring and immediate postoperative neurological examination were normal. Sixty hours after surgery, she developed a tetraplegia. The immediate MRI and CT scan of the spine were negative. Two days after, a new MRI revealed an ischemic cervical lesion at the level C5-C6. After 1 week, she gradually improved breathing and motility/sensibility at the extremities. After 4 months of intensive neurologic rehabilitation, the patient improved to ASIA grade D and was discharged. At 1-year follow, the neurologic recovery was nearly completed.

METHODS

We performed a systematic review of the literature through PubMed and Embase database focused on delayed postoperative cervical spinal cord lesion after a thoraco-lumbar fusion for spinal deformity.

RESULTS

Only 14 cases of neurological injuries at levels above the site of surgery have been previously reported and never in Prader Willy Syndrome. All patients were adolescent and 86,7% were females but no specific risk factors were found.

CONCLUSIONS

Delayed postoperative neurological deficit far from the surgical site can be considered a specific subgroup of these rare complication that can occur several hours after spine surgery, regardless of intraoperative complication. Despite the rarity of this complication, clinicians should be aware of it. Perioperative optimization of spinal cord perfusion and close neurological examination in first postoperative days may be helpful to quickly recognize and treat this complication.

High Prevalence of Scoliosis in a Large Cohort of Patients with Prader-Willi Syndrome

The characteristics of scoliosis were investigated in a large cohort of children and adults with Prader–Willi syndrome (PWS), analysing the role of age, gender, puberty, body mass index (BMI), genotype and growth hormone therapy (GHT) on its onset and severity. A retrospective cross-sectional study was performed in 180 patients with genetically confirmed PWS (96 females), aged 17.6 ± 12 years. Eighty-five subjects (47%) were obese. One hundred and fifty subjects (83.3%) were on GHT, while 30 patients had never been treated. Overall, 150 subjects (83.3%) were affected by scoliosis, 80.2% of children and adolescents and 87.8% of adults. A mild degree of scoliosis was observed in 58 patients (38.7%), moderate in 43 (28.7%) and severe in 49 (32.6%). Median age at diagnosis of scoliosis was 6.3 years, while the severe forms were diagnosed earlier (median age: 3.8 years). The cumulative probability at 5 years of age was equal to 0.403 and almost doubled at 15 years. No significant associations were found between scoliosis and genotype, gender, pubertal stage, GHT and BMI. A corset was prescribed to 75 subjects (50%) at a median age of 7.5 years, while 26 subjects (17.3%) underwent surgery at a median age of 13.1 years. Our data indicate that scoliosis is one of the major concerns for PWS patients that increases with age, and therefore suggest the need for regular systematic monitoring of spinal deformity from paediatric age.

Hospital outcomes of scoliosis surgery in children with Prader-Willi Syndrome: comparison with adolescent idiopathic scoliosis

PURPOSE

The purpose of this study was to evaluate the peri-operative outcomes of patients with Prader-Willi Syndrome (PWS) undergoing spinal deformity correction and compare the outcomes to patients with adolescent idiopathic scoliosis (AIS).

METHODS

A retrospective review of the Kid's Inpatient Database was performed from 2000 to 2012 to identify all pediatric patients with scoliosis undergoing spinal fusion. Cohorts were created on the basis of PWS diagnosis and adolescent idiopathic scoliosis. Statistical analysis was performed for differences in post-operative outcomes between these two patient cohorts.

RESULTS

Between 2000 and 2012, the number of spinal fusions performed increased by 24.6 and 32.2% in the PWS and adolescent idiopathic scoliosis populations, respectively. There was no difference between the incidence of major complications in PWS patients when compared to AIS (1.7% vs. 1.0% in idiopathic scoliosis; p = 0.362). Although there was no significant difference in the rate of overall minor complications, PWS patients were demonstrated to be more likely to experience post-operative pneumonia (p < 0.0001) and implant complications (p < 0.001).

CONCLUSION

Patients with scoliosis associated with PWS do not have any increased risk of major complications following spinal deformity correction when compared to patients with adolescent idiopathic scoliosis. Two important minor complications to keep in mind when surgically treating scoliosis in PWS patients include pulmonary and implant-related complications.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

Role of Body Cast Application for Scoliosis Associated With Prader-Willi Syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a rare genetic syndrome, with a prevalence of infantile scoliosis of ~23%. These curves are likely related to severe hypotonia. Approximately 15% of children with PWS will need surgical intervention for their scoliosis. The purpose of this study was to evaluate the effectiveness of curing or controlling moderate and severe infantile scoliosis curves in children with PWS.

METHODS

This single institution, retrospective study of patients with PWS and infantile scoliosis reviewed 34 consecutive children with >24 months follow-up from initiation of serial spinal casting. Cobb angle comparison measurements of radiographs taken precasting, during treatment, and at follow-up were performed. Rib-vertebral angle difference, Nash-Moe rotation, and space available for lung measurements were followed. Outcomes were stratified as "Cured," "Braced," and "Surgery."

RESULTS

Average age for first cast for the entire study was 32 months (range, 14 to 64), undergoing 8 casts (range, 3 to 18) over 25 months (range, 9 to 57) for an initial curve of 54 degrees (range, 27 to 106 degrees), which improved to 27 degrees (range, 11 to 78 degrees). In total, 12 patients (35%) were in the Cured group, following 6 casts over 17 months, with an initial curve of 44±14 degrees improving to 17±5 degrees at the end of treatment, and 20±18 degrees at 68-month follow-up. In total, 18 patients were in the Braced group, with curves initially improving from 55±14 degrees to 35±14 degrees, but at 47±20 degrees at 51-month follow-up. Four patients needed surgery, with initial curves 85 degrees (range, 54 to 106 degrees), but surgery could be postponed 56 months (range, 40 to 73) by casting. Rib-vertebral angle difference was not prognostic.

CONCLUSIONS

Serial spinal casting is effective in for treating infantile scoliosis in children with PWS. One third of patients had their curve resolved, at least temporarily, where they were braced and cast free. The others were able to delay surgery for a number of years. Initial curves <50 degrees in children <3 years of age seem to have the best prognosis.

LEVEL OF EVIDENCE

Level IV.

Evolution of Hip Dysplasia in Pediatric Patients With Prader-Willi Syndrome Treated With Growth Hormone Early in Development

BACKGROUND

Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by obesity, hypotonia, feeding difficulties, obesity, musculoskeletal manifestations including scoliosis, and hip dysplasia (HD). The aim of this study was to characterize the clinical and radiographic evolution of HD in the pediatric PWS population.

METHODS

The authors performed a retrospective cohort study of 72 patients (147 anteroposterior pelvic radiographs) between January 2004 and December 2016. Center-edge angle (CEA) of Wiberg, acetabular index (AI), and neck-shaft angle (NSA) were measures in all hips. The relationship between radiographic and demographic parameters of age, sex, and body mass index z-score (BMIzs) were assessed.

RESULTS

A total of 274 radiographic measurements were performed and analyzed in 72 patients. The mean CEA, AI, and NSA were 21.8±7.1 degrees (range, 5 to 35 degrees), 16.7±7 degrees (range, 5 to 45 degrees), and 142±8.5 degrees (range, 128 to 165 degrees), respectively. HD was diagnosed in 79 (29%) hip radiographs and varied significantly between the age groups (P<0.01). A statistically significant association was identified between age and CEA [β coef, 0.80; 95% confidence interval (CI), 0.6-1; P<0.01], AI (β coef, -0.90; 95% CI, -1.1 to -0.7; P<0.01), and NSA (β coef, -1.11; 95% CI, -1.4 to -0.9; P<0.01) angles. Sex and BMIzs were not identified as independent predictors of radiographic hip angles (P>0.1).

CONCLUSIONS

The present study demonstrated favorable evolution of hip radiographic parameters in the PWS population treated with growth hormone early in development. This finding should prompt orthopedists to consider observation alone in the management algorithm for HD in patients with PWS.

LEVELS OF EVIDENCE

Level III-a retrospective comparative study.

Comparison of Hip and Knee Arthroplasty Rates of Individuals With and Without Prader-Willi Syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a complex genetic condition, affecting between 1:10,000 and 1:30,000. The prevalence of hip dysplasia in children with PWS is reportedly between 8% and 30%, but the long-term consequences of residual hip dysplasia remain largely unknown in this population. The purpose of this study was to comparatively estimate the number of total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures performed on adults with and without PWS, using a national hospital discharge database, in an effort to elucidate long-term outcomes and guide clinicians treating orthopaedic concerns in younger individuals with PWS.

METHODS

The National Inpatient Sample of the Healthcare Cost and Utilization Project is the largest all-payer inpatient care database, containing annual data from >7 million hospital stays; sampling weights and stratification variables are provided for producing estimates of >35 million hospitalizations nationwide. THA and TKA procedures were identified, then stratified by whether or not the patient had a diagnosis of PWS. The ages of the 2 groups and sex mix were compared, as was the length of stay for the procedure, and discharge status.

RESULTS

From 2004 to 2014, 9.4 million patients nationwide, by weighted estimate, underwent THA (3.1 million) or TKA (6.3 million). Sixty-five patients were identified as having the diagnosis of PWS (39 with THA, 26 with TKA); 7 patients per million having hip or knee arthroplasties had PWS. Sixty-eight percent of those with PWS were younger than 50 years, compared with only 7% of those without PWS (P<0.001). The female:male prevalence was 47:53 for patients with PWS and 60:40 for the total group. The mean length of stay was similar, but patients with PWS were more likely to be transferred to another facility after surgery (77% vs. 36%; P=0.008).

CONCLUSIONS

Hip dysplasia prevalence is higher in persons with PWS, but the rate of late treatment with THA is much lower than in the general population. We recommend only active observation for stable and improving hips in young children with PWS, as the consequences of overtreatment can be serious, including further delaying their neuromuscular development, and exposure to possibly unnecessary perioperative risks.

LEVEL OF EVIDENCE

Nation-wide database analysis, Level IV.

Clinical Observations and Treatment Approaches for Scoliosis in Prader-Willi Syndrome

Prader–Willi syndrome (PWS) is recognized as the first example of genomic imprinting, generally due to a de novo paternal 15q11-q13 deletion. PWS is considered the most common genetic cause of marked obesity in humans. Scoliosis, kyphosis, and kyphoscoliosis are commonly seen in children and adolescents with PWS with a prevalence of spinal deformities cited between 15% to 86%. Childhood risk is 70% or higher, until skeletal maturity, with a bimodal age distribution with one peak before 4 years of age and the other nearing adolescence. As few reports are available on treating scoliosis in PWS, we described clinical observations, risk factors, therapeutic approaches and opinions regarding orthopedic care based on 20 years of clinical experience. Treatments include diligent radiographic screening, starting once a child can sit independently, ongoing physical therapy, and options for spine casting, bracing and surgery, depending on the size of the curve, and the child’s age. Similarly, there are different surgical choices including a spinal fusion at or near skeletal maturity, versus a construct that allows continued growth while controlling the curve for younger patients. A clear understanding of the risks involved in surgically treating children with PWS is important and will be discussed.

Wave Change of Intraoperative Transcranial Motor-Evoked Potentials During Corrective Fusion for Syndromic and Neuromuscular Scoliosis

BACKGROUND

There is little information on intraoperative neuromonitoring during correction fusion surgery for syndromic scoliosis.

OBJECTIVE

To investigate intraoperative TcMEPs and conditions (body temperature and blood pressure) for syndromic scoliosis.

METHODS

The subjects were 23 patients who underwent 25 surgeries for corrective fusion using TcMEP. Patients were divided into groups based on a decrease (DA+) or no decrease (DA-) of the amplitude of the TcMEP waveform of ≥70%. The groups were compared for age, sex, disease, type of surgery, fusion area, operation time, estimated blood loss, body temperature, blood pressure, Cobb angle, angular curve (Cobb angle/number of vertebra), bending flexibility, correction rate, and recovery.

RESULTS

The mean Cobb angles before and after surgery were 85.2° and 29.1°, giving a correction rate of 68.2%. There were 16 surgeries (64.0%) with intraoperative TcMEP wave changes. The DA+ and DA- groups had similar intraoperative conditions, but the short angular curve differed significantly between these groups. Amplitude deterioration occurred in 4 cases during first rod placement, in 8 during rotation, and in 3 during second rod placement after rotation. Seven patients had complete loss of TcMEP. However, most TcMEP changes recovered after pediclectomy or decreased correction. The preoperative angular curve differed significantly between patients with and without TcMEP changes (P < .05).

CONCLUSION

Intraoperative TcMEP wave changes occurred in 64.0% of surgeries for corrective fusion, and all but one of these changes occurred during the correction procedure. The angular curve was a risk factor for intraoperative motor deficit.

Growth hormone receptor (GHR) gene polymorphism and scoliosis in Prader-Willi syndrome

OBJECTIVE

A growth hormone receptor (GHR) gene polymorphism impacts sensitivity to endogenous and exogenous growth hormone (GH) to moderate growth and development. Increased sensitivity may accelerate spinal growth and contribute to scoliosis, particularly in GH-deficient and treated populations such as Prader-Willi syndrome (PWS). Therefore, we examined the relationship between GHR genotype and scoliosis (case and control) in PWS cohorts.

DESIGN

We utilized a case-control design in a study of 73 subjects (34M; 39F) with genetically confirmed PWS in 32 individuals previously diagnosed with moderate to severe scoliosis (mean age=16.9±10.2years; age range of 1 to 41years) and 41 adults with no evidence of scoliosis (mean age=30.8±9.7years; age range of 18 to 56years). The GHR gene polymorphism was determined using PCR specific primers to capture the two recognized GHR gene fragment sizes [i.e., full length (fl) or exon 3 deletions (d3)].

RESULTS

Twenty-three (72%) of the 32 case subjects with scoliosis required surgical correction with an approximately equal balance for gender and PWS genetic subtype among cases and 41 control subjects without scoliosis. The GHR d3/d3 genotype was identified in N=2 of 8 (25%) cases with scoliosis and the d3/fl genotype was identified in N=11 of 25 (44%) cases with scoliosis but the distribution difference did not statistically differ. The GHR fl/fl genotype was correlated with a significantly faster rate and heavier weight gain among case subjects.

CONCLUSION

Our examination of demographic and genetic markers associated with scoliosis and surgical repair in PWS found no evidence to support differences in gender, PWS genetic subtype or GHR d3 allele distributions among the case vs control groups. Those with fl/fl alleles were heavier than those with d3/d3 or d3/fl genotypes and warrant further study with a larger sample size and possibly to include other vulnerable populations requiring growth hormone treatment.

The Prevalence and Treatment of Hip Dysplasia in Prader-Willi Syndrome (PWS)

BACKGROUND

Prader-Willi syndrome (PWS) is a genetic disorder with multisystem involvement. There are a number of associated orthopaedic manifestations, the most recognized of which is scoliosis. The aim of this study was to assess the prevalence of hip dysplasia and to investigate its treatment in patients with PWS.

METHODS

Following IRB approval, all patients seen at our institution's Prader-Willi multidisciplinary clinic were retrospectively reviewed. Only patients with an ultrasound, anteroposterior (AP) spine, AP abdomen, AP hip radiograph, and/or skeletal survey were included in the study. The presence of hip dysplasia was determined based on ultrasonographic and/or radiographic measurements performed by a single fellowship trained pediatric orthopaedic surgeon. A multivariable logistic regression analysis was used to test the association between patient demographics and the prevalence of hip dysplasia. Age at diagnosis, treatment type, and outcomes were recorded for patients that underwent treatment for hip dysplasia.

RESULTS

Hip dysplasia was identified in 30% (27/90) of the patient population. Two of the 27 patients (7.4%) had normal films but had a history of resolved hip dysplasia. Prevalence was not associated with sex (P=0.7072), genetic subtype (P=0.5504), race (P=0.8537), ethnicity (P=0.2191), or duration of follow-up (P=0.4421). Eight of the 27 patients (30%) underwent hip treatment by Pavlik harness (2/8), Pavlik harness and closed reduction (1/8), closed reduction (3/8), open reduction (1/8), and unspecified hip surgery (1/8). The mean age at diagnosis was 2 months for the patients that were successfully treated for hip dysplasia (3/8) and 12 months for those who had residual dysplasia following the treatment (5/8).

CONCLUSIONS

Our study demonstrates a higher prevalence of hip dysplasia in patients with PWS than previously documented. The age at which hip dysplasia develops remains unknown; therefore, we recommend an ultrasound screening for all infants with PWS at 6 weeks of age and subsequent radiographic studies at 1, 2, 5, 10, and 15 years of age to allow for early diagnosis and intervention.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Complications associated with surgical repair of syndromic scoliosis

Background

There are a number of syndromes that have historically been associated with scoliosis e.g.: Marfan, Down, and Neurofibromatosis. These syndromes have been grouped together as one etiology of scoliosis, known as syndromic scoliosis. While multiple studies indicate that these patients are at high risk for perioperative complications, there is a paucity of literature regarding the collective complication rates and surgical needs of this population.

Methods

PubMed and Embase databases were searched for literature encompassing the surgical complications associated with the surgical management of patients undergoing correction of scoliosis in the syndromic scoliosis population. Following exclusion criteria, 24 articles were analyzed for data regarding these complications.

Results

The collective complication rates and findings of these articles were categorized based on specific syndrome. The rates and types of complications for each syndrome and the special needs of patients with each syndrome are discussed. Several complication trends of note were observed, including but not limited to the universally nearly high rate of wound infections (>5% in each group), high rate of pulmonary complications in patients with Rett syndrome (29.2%), high rate (>10%) of dural tears in Marfan and Ehlers-Danlos syndrome patients, high rate (>20%) of implant failure in Down and Prader-Willi syndrome patients, and high rate (>25%) of pseudarthrosis in Down and Ehlers-Danlos patients.

Conclusions

Though these syndromes have been classically grouped together under the umbrella term “syndromic,” there may be specific needs for patients with each of these ailments. Given the high rate of complications, further research is necessary to understand the unique needs for each of these patient groups in the preoperative, intraoperative, and postoperative settings.

Growth hormone treatment for osteoporosis in patients with scoliosis of Prader-Willi syndrome

BACKGROUND

Patients with Prader-Willi syndrome (PWS) have fragile bones. Osteoporosis is a major concern in scoliosis surgery. Our aim was to investigate bone mineral density (BMD) in PWS patients and to verify the efficacy of and scoliosis deterioration with growth hormone (GH) administration for osteoporosis.

METHODS

We followed 148 PWS patients who underwent lumbar spine (L2-4) BMD testing. Sixty-four patients had scoliosis, and 84 were non-scoliosis patients. Patients were treated with GH (0.245 mg/kg/week) until they reached a skeletal age of 17 years for males and 15 years for females. We also evaluated the effect of GH treatment on BMD in 101 patients (60 males, 41 females) undergoing BMD testing more than twice. The mean patient age was 5.4 years. The mean duration of GH administration was 54 months.

RESULTS

Mean lumbar BMD was 0.567 g/cm(2). Fifty patients (33.8%) had osteoporosis and 41 (27.7%) had osteopenia. There was no significant difference in mean BMD between patients with scoliosis (0.598 g/cm(2)) and without scoliosis (0.548 g/cm(2)). GH treatment caused a significant increase in Z score (pre-GH: mean -2.28 vs. post-GH: mean -1.53, P < 0.001). There was no statistical difference in the prevalence of scoliosis between the GH treatment group (45/112, 40.1%) and non-treatment group (19/36, 52.8%).

CONCLUSIONS

Among patients with PWS, 61.5% had low BMDs. GH administration significantly improved the lumbar BMD (Z score). There were no statistically significant differences in the prevalence of scoliosis among patients who received GH treatment compared to patients who did not.

Prevalence of complications in neuromuscular scoliosis surgery: a literature meta-analysis from the past 15 years

PURPOSE

Our objectives were primarily to review the published literature on complications in neuromuscular scoliosis (NMS) surgery and secondarily, by means of a meta-analysis, to determine the overall pooled rates (PR) of various complications associated with NMS surgery.

METHODS

PubMed and Embase databases were searched for studies reporting the outcomes and complications of NMS surgery, published from 1997 to May 2011. We focused on NMS as defined by the Scoliosis Research Society's classification. We measured the pooled estimate of the overall complication rates (PR) using a random effects meta-analytic model. This model considers both intra- and inter-study variation in calculating PR.

RESULTS

Systematic review and meta-analysis were performed for 68 cohort and case-control studies with a total of 15,218 NMS patients. Pulmonary complications were the most reported (PR = 22.71 %) followed by implant complications (PR = 12.51 %), infections (PR = 10.91 %), neurological complications (PR = 3.01 %) and pseudoarthrosis (PR = 1.88 %). Revision, removal and extension of implant had highest PR (7.87 %) followed by malplacement of the pedicle screws (4.81 %). Rates of individual studies have moderate to high variability. The studies were heterogeneous in methodology and outcome types, which are plausible explanations for the variability; sensitivity analysis with respect to age at surgery, sample size, publication year and diagnosis could also partly explain this variability. In regard to surgical complications affiliated with various surgical techniques in NMS, the level of evidence of published literature ranges between 2+ to 2-; the subsequent recommendations are level C.

CONCLUSION

NMS patients have diverse and high complication rates after scoliosis surgery. High PRs of complications warrant more attention from the surgical community. Although the PR of all complications are affected by heterogeneity, they nevertheless provide valuable insights into the impact of methodological settings (sample size), patient characteristics (age at surgery), and continual advances in patient care on complication rates.

Escoliosis y síndrome de Prader-Willi: a propósito de 5 casos intervenidos quirúrgicamente

OBJETIVO: Analizar los resultados y las complicaciones del tratamiento quirúrgico de la escoliosis, en pacientes portadores del Síndrome de Prader-Willi, para verificar si se justifica este tipo de tratamiento. MÉTODOS: Análisis retrospectivo de las fichas clínicas y radiografías de los cinco pacientes portadores del Síndrome de Prader-Willi que consultaron en el Departamento de Escoliosis entre los años 2005 y 2010, y fueron operados. RESULTADOS: La edad de la consulta inicial fue en promedio 3,6 años; el promedio de escoliosis fue 61º, el que aumentó a 65º al momento de la cirugía. El promedio de operaciones realizadas fue 2,8 por paciente, lográndose una corrección promedio de 35%. Los motivos de las reintervenciones fueron pérdida de corrección en 4 casos (28,5%), aflojamiento de ganchos en 2 (14,3%) y xifosis referente a la instrumentación en uno (7,1%) No hubo complicaciones graves. CONCLUSIONES: Aún cuando la literatura muestra autores poco proclives a indicar cirugía en este tipo de pacientes, por la elevada tasa de complicaciones graves, la ausencia de ellas en nuestro medio hace mantener válidos los mismos criterios quirúrgicos que en escoliosis idiopática.

Prader-willi syndrome: clinical aspects

Prader-Willi Syndrome (PWS) is a complex multisystem genetic disorder that shows great variability, with changing clinical features during a patient's life. The syndrome is due to the loss of expression of several genes encoded on the proximal long arm of chromosome 15 (15q11.2-q13). The complex phenotype is most probably caused by a hypothalamic dysfunction that is responsible for hormonal dysfunctions and for absence of the sense of satiety. For this reason a Prader-Willi (PW) child develops hyperphagia during the initial stage of infancy that can lead to obesity and its complications. During infancy many PW child display a range of behavioural problems that become more noticeable in adolescence and adulthood and interfere mostly with quality of life. Early diagnosis of PWS is important for effective long-term management, and a precocious multidisciplinary approach is fundamental to improve quality of life, prevent complications, and prolong life expectancy.

Growth hormone supplement treatment reduces the surgical risk for Prader-Willi Syndrome patients

INTRODUCTION

Many complications have been reported to occur with surgery for scoliosis in Prader-Willi Syndrome (PWS). However, growth hormone (GH) treatment has contributed to improvements in height, body composition, bone density and breathing functions in PWS patients. The purpose of this study was to investigate patients who underwent surgery for scoliosis in PWS.

MATERIALS

There were 136 PWS patients being followed-up by the Pediatrics Department of our hospital. Among these, we investigated nine patients who had undergone surgery. Their mean age was 11 years. The mean follow-up period was 6 years 10 months.

RESULTS

The mean body mass index was 22.5 kg/m(2). GH therapy was administered to eight patients. Brace treatment was performed in two patients. Spinal correction and fusion were performed in six patients, and the growing rod method was performed in three patients. Necessary reoperations were performed in two patients. For the total 11 surgeries in the nine patients, the mean blood loss was 397 ml and the mean operation time was 4 h and 20 min. The mean Cobb angles were 76.0 degrees preoperatively and 35.8 degrees at follow-up. Regarding complications, one patient experienced early dislodgment of the hook and one patient experienced a superior wound infection.

CONCLUSION

There were no severe complications such as deep infections or neurovascular damage. A few obese patients underwent surgery, but there were no dangerous complications. Overall, we consider that GH treatment before surgery may reduce postoperative complications. The growing rod method was effective for PWS patients who resisted brace treatment owing to mental retardation.

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.

Pathways that distinguish simple from complex scoliosis repair and their outcomes

PURPOSE OF REVIEW

Surgical management of spinal deformities in patients with neuromuscular diseases or other underlying comorbidities is often challenging, as this population is at an increased risk of experiencing complications. Identifying these patients early on in the preoperative planning process is imperative in order to improve patient outcomes.

RECENT FINDINGS

Many recent studies have identified risk factors associated with perioperative and postoperative complications, including neuromuscular diseases, genetic syndromes, traumatic nerve/muscle injuries, seizure disorders, decreased cognitive ability, poor pulmonary status, restrictive lung disease, history of frequent pneumonias, sleep apnea, malnutrition, cardiac disease, immune-compromised patients, social status, ambulatory status, and the complexity of the procedure itself.

SUMMARY

Management of spinal deformities in patients with neuromuscular diseases or other underlying comorbidities must be approached cautiously and in a multidisciplinary manner. Identifying these comorbidities early on, understanding their influence on patient outcomes after spinal surgery and managing high-risk patients through a common therapeutic and clinical pathway can help to improve patient outcomes.

Treatment of scoliosis in patients affected with Prader-Willi syndrome using various techniques

BACKGROUND

The incidence of spinal deformity in children with Prader-Willi syndrome (PWS) is high, with 86% of these patients found to have a significant structural scoliosis; however, there are very few case reports describing surgical treatment for this deformity.

METHODS

The authors reviewed a case series consisting of 6 patients who underwent spine surgery for scoliosis. Children's mean age at index surgery was 12 years and 10 months (range, 10 to 15 yrs). Clinical evaluation revealed the typical phenotypic features of the PWS in all of the patients; 4 subjects had a karyotype confirmation of PWS. Major structural curves showed preoperative mean Cobb angles of 80.8 degrees (range, 65 degrees to 96 degrees ). Hybrid instrumentation with sublaminar wires, hooks and screws was used in the first 2 patients, while the remaining 4 were treated with titanium pedicle screw constructs.

RESULTS

The mean clinical and radiological follow-up was 3 years and 10 months (range, 2 years to 9 years). Major complication rate was 50%. One patient who developed a major intraoperative complication (paraparesis) prevented spinal fusion to be obtained: the neurologic deficit resolved completely after instrumentation removal. Solid arthrodesis and deformity correction in both coronal and sagittal plane was, however, achieved in the other 5 cases and no significant curve progression was observed at follow-up. Another major short-term complication was encountered 3 months after surgery in a patient who experienced the detachment of a distally located rod and required correction through revision surgery and caudal extension by one level. Cervico-thoracic kyphosis was seen in 1 patient who did not require revision surgery.

CONCLUSIONS

Spine reconstructive surgery in patients with PWS is rare and highly demanding.The best method of reconstruction is posterior multilevel pedicle screw fixation. Moreover, even with modern techniques, the risk of complications is still high. These new techniques, however, have shown to improve the postoperative course by allowing for immediate mobilization without any brace or cast. The use of the growing rod techniques, requiring repeated surgeries, should be carefully evaluated in each single case.

Epidemiological aspects of scoliosis in a cohort of Japanese patients with Prader-Willi syndrome

BACKGROUND CONTEXT

The prevalence of scoliosis in Prader-Willi syndrome (PWS) is high; however, the prevalence of PWS is rare, with one person in 10,000 to 20,000 affected. The etiology and characteristics of scoliosis associated with PWS remain unidentified. In addition, it is believed that the speedup of growth associated with growth hormone (GH) supplement treatment may influence the deterioration of scoliosis in PWS.

PURPOSE

To investigate scoliosis in Japanese patients with PWS.

STUDY DESIGN

Retrospective observational study.

PATIENT SAMPLE

We investigated 101 patients (67 men, 34 women) who were followed up from November 2002 to January 2008. All patients were diagnosed using fluorescence in situ hybridization or the methylation test. Of the 101 patients, 80 had an inherited deletion of chromosome 15q11-13 (deletion) and 21 patients had no deletion, including those with uniparental disomy.

OUTCOME MEASURES

1) Prevalence of scoliosis; 2) association of scoliosis with GH treatments; 3) association of scoliosis with genotype; 4) clarification of PWS scoliosis characteristics; and 5) analysis of severe PWS scoliosis patients (Cobb angle greater than 40 degrees ). Scoliosis for our study was defined as scoliosis with a Cobb angle greater than 10 degrees .

METHODS

To investigate PWS-associated scoliosis, we used spinal X-ray examinations. The pattern of scoliosis was classified into three types: primary single lumbar or thoracolumbar curve (Type 1), double curve (Type 2), and primary single thoracic curve (Type 3). For statistical analysis, chi-square tests for the distribution of patients were used (p<.05).

RESULTS

1) Scoliosis was found in 38.6% (39/101) of patients with PWS. 2) There was no statistical difference in the prevalence of scoliosis between the GH treatment group (32.8%) and the GH nontreatment group (group with no GH treatments) (46.5%) (p=.16, chi-square test). 3) There was no statistical difference in the prevalence of scoliosis between the deletion group (38.8%) and the nondeletion group (38.1%) (p=.84, chi-square test). 4) Scoliosis was classified into three types, according to single or double curve scoliosis and position of scoliosis. The prevalence of these groups was 61.5% for Type 1 (primary single lumbar and thoracolumbar curve), 48.7% for lumbar curve convex on the left side, 28.2% for Type 2 (double curve), and 10.3% for Type 3 (primary single thoracic curve). 5) Severe scoliosis was found in nine patients (8.9%, 9/101). Type 2 was found in 66.7% (6/9) of patients with severe scoliosis. During the follow-up period, two patients changed from Type 1 to Type 2.

CONCLUSIONS

Scoliosis in PWS can be classified into three types. A lumbar curve convex on the left side was found in most patients. In addition, severe deterioration of scoliosis was found in Type 2 patients. Therefore we recommend careful, ongoing observations for patients showing double curve tendencies.

Bone mineral density and effects of growth hormone treatment in prepubertal children with Prader-Willi syndrome: a randomized controlled trial

BACKGROUND

Bone mineral density (BMD) is unknown in children with Prader-Willi syndrome (PWS), but is decreased in adults with PWS. In patients with GH deficiency, BMD increases during GH treatment.

OBJECTIVES

The aim of the study was to evaluate BMD in children with PWS and to study the effects of GH treatment.

DESIGN

We conducted a randomized controlled GH trial. Forty-six prepubertal children were randomized into either a GH-treated group (1.0 mg/m(2) . d) or a control group for 2 yr. At start, 6, 12, and 24 months of study, total body and lumbar spine BMD were measured by dual-energy x-ray absorptiometry, and lumbar spine bone mineral apparent density (BMAD) was calculated.

RESULTS

Baseline total body and lumbar spine BMD sd score (SDS) were normal [mean (sd), -0.2 SDS (1.1) and -0.4 SDS (1.2), respectively]. BMADSDS, which corrects for short stature, was also normal [mean (sd), 0.40 SDS (1.1)]. Total body BMDSDS decreased during the first 6 months of GH (P < 0.0001), but increased during the second year of treatment. After 24 months of study, total body and lumbar spine BMDSDS, and the BMADSDS did not significantly differ between GH-treated children and randomized controls (P = 0.30, P = 0.44, and P = 0.47, respectively). Results were similar when corrected for body mass index SDS. Repeated measurements analysis showed a significant positive association between IGF-I SDS and total body and lumbar spine BMDSDS, but not with BMADSDS.

CONCLUSIONS

Our results show that prepubertal children with PWS have a normal BMD. GH treatment had no effect on BMD, except for a temporary decrease of total body BMDSDS in the first 6 months.

Scoliosis in patients with Prader Willi Syndrome - comparisons of conservative and surgical treatment

In children with Prader Willi syndrome (PWS), besides growth hormone (GH) therapy, control of the food environment and regular exercise, surgical treatment of scoliosis deformities seems the treatment of choice, even though the risks of spinal surgery in this specific population is very high. Therefore the question arises as to whether the risks of spinal surgery outweigh the benefits in a condition, which bears significant risks per se. The purpose of this systematic review of the Pub Med literature was to find mid or long-term results of spinal fusion surgery in patients with PWS, and to present the conservative treatment in a case study of nine patients with this condition.

METHODS

Types of studies included; all kinds of studies; retrospective and prospective ones, which reported upon the outcome of scoliosis surgery in patients with PWS.Types of participants included: patients with scoliosis and PWS.Type of intervention: surgery.Search strategy for identification of the studies; Pub Med; limited to English language and bibliographies of all reviewed articles.Nine patients with PWS from our data-base treated conservatively have been found, being 19 years or over at the time this study has been performed. The results of conservative management are described and related to the natural history and treatment results found in the Pub Med review.

RESULTS

From 2210 titles displayed in the Pub Med database with the key word being "Prader Willi syndrome", 5 different papers were displayed at the date of the search containing some information on the outcome of surgery and none appeared to contain a mid or long-term follow-up. The PWS patients treated conservatively from our series all stayed below 70 degrees and some of which improved.

DISCUSSION

If the curve of scoliosis patients with PWS can be kept within certain limits (usually below 70 degrees) conservatively, this treatment seems to have fewer complications than surgical treatments. The results of our retrospective study of nine patients demonstrate that scoliosis in this entity plays only a minor role and surgery is unnecessary when high quality conservative management exists.

CONCLUSION

There is lack of the long follow-up studies in post-surgical cases in patients with PWS and scoliosis. The rate of complications of spinal fusion in patients with PWS and scoliosis is very high and the death rates have been found to be higher than in patients with Adolescent Idiopathic Scoliosis (AIS). The long-term side-effects of the intervention are detrimental, so that the risk-benefit ratio favours the conservative approaches over spinal fusion surgery.

The effect of posterior thoracic spine anatomical structures on motion segment flexion stiffness

STUDY DESIGN

This in vitro human cadaveric study tested the loss of thoracic motion segment flexion stiffness after sequential posterior upper instrumented vertebra anchor placement techniques and posterior column destabilization.

OBJECTIVE

This study was designed to determine the possible destabilizing effects of upper thoracic instrumentation anchor site preparation.

SUMMARY OF BACKGROUND DATA

Proximal junctional kyphosis after instrumentation and arthrodesis for scoliosis and related spine deformities has recently been reported to range from 10% to 46%. The effect of posterior skeletal dissection associated with upper instrumented vertebra anchor placement on adjacent motion segment flexion stiffness has not been previously studied. METHODS.: Twenty-three intact thoracic motion segments were obtained from 6 human cadavers. Biomechanical testing was performed with each motion segment flexed to approximately 3.2 degrees at a rate of 0.1 Hz, with corresponding torques recorded. Data were collected after a series of 6 posterior procedures. Differences with P value <0.01 were considered significant and those with P value <0.05 marginally significant.

RESULTS

Supratransverse process hook, supralaminar hook, pedicle screw placement, or pedicle screw removal done, bilaterally, produced similar, small (range, 2.09%-6.03%), nonsignificant reductions in motion segment flexion stiffness. But when totaled, these 4 procedures resulted in a significant 16.31% loss of flexion stiffness. The fifth procedure of supraspinous and interspinous process ligament transection added a marginally significant 6.59% incremental loss of flexion stiffness. Supralaminar hook site preparation combined with supraspinous and interspinous process ligament transection resulted in a marginally significant 12.62% incremental loss of flexion stiffness. Transection of the remaining posterior structures (facet joints and all other posterior soft tissue structures) produced a significant additional flexion stiffness loss of 44.72%. The anterior column alone provided only 32.39% of the total motion segment flexion stiffness. Transection of all posterior stabilizing structures, similar to a Smith-Peterson/chevron/Ponte resection, decreased motion segment flexion stiffness significantly, 67.61%.

CONCLUSION

Posterior thoracic skeletal structures involved in upper instrumented vertebra exposure andanchor placement were found to contribute to adjacent segment flexion stiffness. Although stiffness loss was small after individual procedures, the effects were additive for routinely used combinations.

Scoliosis in patients with Prader-Willi Syndrome

OBJECTIVE

Our goals were to determine the prevalence and estimate the evolution of spinal deformities in patients suffering from Prader-Willi syndrome; find out which kind of spine deformity predominates regarding genotype and clinical patterns; and evaluate the affect of growth-hormone treatment on the onset and progression of spinal deformities.

PATIENTS AND METHODS

This was a retrospective longitudinal, clinical, and radiologic study. One hundred forty-five children followed between 1980 and 2006 were studied in 2 referral centers for Prader-Willi syndrome. Genetic testing confirmed the diagnosis in 133 patients. Ninety-three patients (64%) received growth-hormone therapy. For statistical analysis, age-adjusted comparison between groups was performed by using multivariate logistic regression.

RESULTS

Mean age of the patients was 10.2 +/- 6.2 years. Sixty-three (43.4%) patients were afflicted with scoliosis. Scoliosis frequency steadily rose with age, and a large majority of patients were affected at skeletal maturity (66.7%). Scoliosis prevalence was not affected by the genotype or by growth-hormone treatment. Patients with higher BMI values had an increased risk of developing a kyphotic deformity in association with scoliosis. We found a statistical association between kyphotic deformity and the need for surgical treatment.

CONCLUSIONS

Scoliosis is a major concern for patients with Prader-Willi syndrome, and a regular (annual) systematic back examination is mandated. The role of growth-hormone treatment on the natural history of scoliosis could not be determined, and careful monitoring during treatment is recommended.