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

Scoliosis and rare diseases: our experience with the Prader-Willi syndrome

INTRODUCTION

Prader-Willi syndrome (PWS) represents a difficult challenge for spine surgeons, due to the association of a structural scoliosis, with a prevalence between 15 and 86%. Conservative therapy is a viable option, but surgery is increasingly becoming the treatment of choice.

METHODS

The authors reviewed a series of 15 patients affected by PWS treated at their institution between 2008 and 2023. The mean age at index treatment was 9 years and 3 months (range 1-15 years) with a prevalence of female subjects. Primary scoliotic curve ranged from 14 to 102°, and mean thoracic kyphosis was 56° (range 20-75°). Eleven patients underwent conservative treatment, while four were treated surgically.

RESULTS

Mean follow-up was 5 years and 3 months (range 2-12 years). Among the 11 patients treated conservatively, only two showed improvements of the coronal curve, while the remaining nine displayed a worsening of the deformity during follow-up. Complication rate after surgery was 75%. One patient developed paraplegia after pedicle screw positioning. One patient displayed rod breakage and PJK that required revision surgery proximally. Hardware deep infection was seen in one case where it was necessary to proceed with instrumentation removal after 10 years.

DISCUSSION AND CONCLUSIONS

Spine surgery represents a convincing option in patients affected by PWS, but the risks of complications are high. Correct patient selection must be the main objective, and multilevel pedicle screw fixation should be the procedure of choice. Traditional growing rod should be prudently evaluated in every single case.

Paediatric syndromic scoliosis: proceedings of the half-day course at the 57th annual meeting of the Scoliosis Research Society

There are some syndromes that present with unique manifestations pertaining to the spinal column. A good working understanding of these common syndromes is useful for the spinal deformity surgeons and related healthcare providers. This review attempts to encompass these unique features and discuss them in three broad groups: hypermobility syndromes, muscle pathology-related syndromes, and syndromes related to poor bone quality. This review explores the features of these syndromes underpinning the aspects of surgical and medical management. This review represents the proceedings of the Paediatric Half-Day Course at the 57th Annual Meeting of the Scoliosis Research Society.

Scoliosis and BMI in patients with Prader-Willi syndrome

Although scoliosis is commonly seen in patients with Prader-Willi syndrome, the patterns and extent of the deformity may change along their growth. Increased body weight is another issue in these patients, and its relationship with scoliosis is still controversial. The aim of this study was to evaluate scoliosis in patients with PWS, and its relationship with BMI. This was a retrospective cohort study in which a series of radiographic images and BMI from each patient were collected, and the data were rearranged following the age at which they were recorded. These patients were subsequently labeled as non-Scoliotic (<10°), Moderate (10° - 39°), and Severe (≥40°) according to their final Cobb angle, also as Normal (≤85%), Overweight (86%-95%), and Obese (≥95%) according to final BMI percentage. Thirty-four patients with age from 1 to 20 years old were recruited for this study, and the mean length of follow-up was 6.6 years. The prevalence of scoliosis was 71% (24 patients in Moderate, and 9 patients in Severe), and 65.6% were either overweight (11 patients) or obese (10 patients). The mean BMI percentage in non-scoliotic patients was 93.10 ± 13.84, which was significantly higher than that of the scoliotic groups ( P  = 0.0180). When looking at the longitudinal change, the non-Scoliotic group had high BMI since childhood, and obese patients had less spine deformity also from early childhood. In this study, we found that the prevalence of scoliosis in Taiwanese population with PWS was 71% without gender preference. Not every patient had a high BMI, and obese patients seemed to have significantly less chance to develop scoliosis. Level III.

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.

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.

Growth Friendly Surgery and Serial Cast Correction in the Treatment of Early-onset Scoliosis for Patients With Prader-Willi Syndrome

BACKGROUND

Prader-Willi syndrome (PWS) patients can present with scoliosis which can be treated with serial cast correction (SCC) or with growth friendly surgery (GFS). This study's purpose was to describe the results of SCC as well as GFS for PWS patients with early-onset scoliosis (EOS).

METHODS

PWS patients were identified from 2 international multicenter EOS databases. Scoliosis, kyphosis, spine height (T1-S1), right/left hemithoracic heights/widths (RHTH, LHTH, RHTW, LHTW) were measured pretreatment, postoperation, and at 2-year follow-up. Complications were recorded.

RESULTS

Overall, 23 patients with 2-year follow-up were identified. Pretreatment; patients treated with SCC (n=10) had mean age of 1.8±0.6 years; body mass index (BMI), 16±1.5 kg/m; scoliosis, 45±18 degrees; kyphosis, 56±9 degrees; T1-S1, 22.4±2.4 cm; RHTH, 8.0±2.0 cm; LHTH, 8.5±1.7 cm; RHTW, 6.6±1.3 cm; and LHTW, 8.0±1.0 cm. Patients treated with GFS (n=13) had mean age of 5.8±2.6 years; BMI, 21±5.4 kg/m; scoliosis, 76±14 degrees; kyphosis, 59±25 degrees; T1-S1, 24.1±3.6 cm; RHTH, 10.0±1.6 cm; LHTH, 10.6±1.6 cm; RHTW, 9.4±2.5 cm; and LHTW, 8.1±2.8 cm. At 2-year follow-up, patients treated with SCC had mean scoliosis 37±11 degrees (18% correction, P=0.06); kyphosis, 42±6 degrees (NS); T1-S1, 26.4±2.1 cm (P<0.01); RHTH, 9.0±1.1 cm (13%; P=0.30); LHTH, 10.0±1.5 cm (18%, P<0.01); RHTW, 7.4±1.1 cm (12%, P<0.01); and LHTW, 8.0±1.0 cm (0%, P=0.34). At 2-year follow-up, patients treated with GFS had mean scoliosis 42±13 degrees (45% correction, P<0.000001); kyphosis, 53±13 degrees (10%, P=0.19); T1-S1, 31.5±5.4 cm (P<0.00001); RHTH, 12.0±2.4 cm (20%; P<0.01); LHTH, 12.0±1.7 cm (13%; P<0.01); RHTW, 9.8±1.3 cm (4%; P=0.27); and LHTW, 7.9±2.3 cm (3%;P=0.11). As an entire group, patients with a BMI>17 kg/m² had more device-related than disease-related complications (P=0.09). Patients treated with SCC had 0.9 complications per patient. Patients treated with GFS had 2.2 complications per patient [≤5 y more often had ≥2 complications (P=0.05)].

CONCLUSIONS

At 2-year follow-up, SCC and GFS were both effective in treating EOS in PWS patients. Patients treated with SCC had significant improvements in spine height and LHTH. Patients treated with GFS had significant improvements in scoliosis magnitude, spine height, RHTH, and LHTH.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

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.

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.

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.

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.