Journal of Spinal Disorders and Techniques Publish Ahead of Print DOI:10.1097/BSD.0000000000000184
The Long-term Outcome of Early Spine Fusion for Scoliosis in Children with Cerebral Palsy
Running title: Early Spine Fusion in Cerebral Palsy
Prakash Sitoula, MD; Laurens Holmes Jr., PhD, DrPH; Julieanne Sees, DO; Kenneth Rogers, PhD, ATC; Kirk Dabney, MD; Freeman Miller, MD Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE 19899, USA
Corresponding author: Freeman Miller, MD Department of Orthopedics Nemours/Alfred I. duPont Hospital for Children P.O. Box 269 Wilmington, DE 19899 Phone: 302-651-5921 Fax: 302-651-5951 Email: [email protected]
Conflicts of Interest and Source of Funding: None
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The Long-term Outcome of Early Spine Fusion for Scoliosis in Children with Cerebral Palsy
Abstract Study Design: Retrospective review of radiographs and charts (case-only) Objective: The aim of this study was to describe the long-term outcomes of spine fusion for neuromuscular scoliosis in children < 10 years of age with cerebral palsy (CP). Summary of Background Data: Severely involved children with CP may develop early onset scoliosis. The outcome of spine fusion is not clear and there are no studies focused on spine fusion in this young patient population. Methods: This is a retrospective review of 33 children who underwent spine fusion with unit rod instrumentation between 1989 and 2006 for CP neuromuscular scoliosis, aged < 10 years at spine fusion, and with follow-up > 5 years. Demographic, medical, and radiographic data were retrospectively assessed. RANOVA and Kaplan-Meier survival estimates were used for data assessment. Results: 33 of 42 patients who underwent spine fusion in this period, 19 boys and 14 girls, met the inclusion criteria. Out of 9 patients who were excluded, 3 were lost to follow up and remaining 6 died within 5 years of surgery. Mean age at surgery was 8.3 years (range, 4.4–9.9). Mean follow-up was 9.8 years (range, 5.5–15.8). Gross motor function classification system level was V in 31 patients and IV in 2 patients. Thirty-one patients (94%) had seizure disorder, 29 patients (88%) had gastric feeding tubes, and 9 patients (27%) had tracheostomy tubes. 85% of the patients had posterior only surgery. Mean Cobb angles preoperative, immediately postoperative, and at final follow-up were 85°, 21°, and 24°, respectively. Mean postoperative pelvic obliquity correction was 15° ± 9°, P < 0.001. At final followup, there was no significant change from the postoperative measurements. Complications included one deep wound infection and 10 other problems. Eleven patients (28.2%) died after a mean follow-up of 5.6 ± 3.8 years. Conclusion: In our cohort with early onset neuromuscular scoliosis, spine fusion was associated with minimal short and long-term morbidity, but there 28% mortality at ten years follow-up and 50% predicted mortality at 15 years. Key Words: early onset scoliosis, neuromuscular scoliosis, quadriplegia, gross motor function classification system (GMFCS), co-morbidities, unit rod, pelvic obliquity, Cobb angle
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Introduction Cerebral palsy (CP) is a static encephalopathy due to insult to an immature brain. The musculoskeletal manifestations are secondary and often progressive due to cumulative effect of spasticity, asymmetric antagonistic muscle involvement, and growth. Scoliosis is a common orthopedic condition seen in CP that develops secondary to poor trunk balance.1 The overall incidence of scoliosis in CP varies from 15 to 25% and the incidence in quadriplegics ranges from 67 to 75%.2-6 The occurrence of scoliosis in CP is directly related to severity of neurologic involvement3,4,6 and is inversely related to ambulation potential.3,6
Curve progression in CP tends to correspond with peak height velocity. 7 This often complicates patient care with hygiene, feeding, and wheelchair transfers. This may also have a negative impact on cardiopulmonary and gastrointestinal functions.8 Pelvic obliquity develops and worsens with curve progression, leading to loss of seating balance8,9 and making frequent wheelchair readjustments necessary. Bracing may have a limited role in supported sitting, but it does not prevent curve progression in quadriplegic CP.7
High and rapid curve progression leads to seating problems that become progressively more difficult to manage, necessitating surgical stabilization of the spine. Currently available surgical options include immediate spinal deformity correction and fusion or utilization of some form of growth-sparing procedures like growing rods. There are a number of studies that have included small numbers of patients younger than 10 years in their cohort; however, there are no studies focused on spine fusion in this isolated young patient population. 10,11 The aim of this study was to assess long-term (follow-up > 5 years) outcome of spine fusion in early onset scoliosis (EOS) in children with CP.
Methods After an IRB approval, we retrospectively reviewed 42 patients with CP who underwent spinal fusion for neuromuscular scoliosis before age 10 years between 1989 and 2006. All patients were treated by two senior authors (FM and KD).
Patient selection
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Inclusion criteria were CP with neuromuscular scoliosis, age less than 10 years at spine fusion, and postoperative follow-up more than 5 years. Thirty-three children (19 boys and 14 girls) met our inclusion criteria and formed the cohort for this study. Nine patients were excluded from long-term aspect of the study: three were lost to follow-up, and six died after a mean follow-up of 2.6 ± 1.1 years. Therefore, 39 out of 42 patients were followed up to their death or more than 5 years. These 39 patients were considered for evaluation of mortality as indicated in the KaplanMeier Survival Estimate.
The medical records were reviewed for patient age, gender, diagnosis, geographic pattern of involvement, mental status, ambulation potential, and gross motor function classification system (GMFCS) level. All patients in the current series had multisystem involvement and the comorbidities included seizure disorder, gastrointestinal issues (gastrostomy-tube feeding and gastroesophageal reflux disease [GERD] with or without Nissen fundoplication), and respiratory problems (obstructive, restrictive, and reactive airway diseases; asthma; recurrent aspiration pneumonitis; and tracheostomy with or without ventilator dependence). Operation time, hospital duration, and ICU stays were also recorded. Estimated blood loss (EBL) during surgery was recorded in milliliters and as blood volume loss (EBL/70x body weight in kilograms). The complications were recorded as intraoperative, early (< 3 months after surgery), and late (> 3 months after surgery). The heights (measured by arm-board measurements12) and weights were recorded preoperatively and at final follow-up. The preoperative body mass index (BMI) was calculated with the initial height and weight. The last clinic visit on record was taken as the final clinical follow-up.
Radiographic evaluation Spinal radiographs (anteroposterior and lateral views) were taken with the patient seated, and Cobb angle, thoracic kyphosis (T5–12), and lumbar lordosis (L1–5) were measured by the Cobb method.13 In the presence of double curves, the larger of the two curves was taken into consideration for all measurement purposes. Pelvic obliquity was measured on an AP spinal radiograph as an angle formed by a line connecting the highest points on the iliac crests with the horizontal.14 The location of curve apex was defined as thoracic (apex between T2 and T11–12 disc), thoracolumbar (apex between T12 and L1), and lumbar (apex between L1–L2 disc and L4).15 All radiographs were measured by the same observer. In some patients, clinical follow-up was longer than the radiographic follow-up because radiographs were not obtained at every clinic visit.
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Surgical indications and technique The treatment protocol for scoliosis in children with CP included using wheelchair support and propped-up sitting orthotics in the growing child until the scoliosis approached 90° or developed severe stiffness making adaptive seating and nursing increasingly more difficult. Therefore, surgical indication was for scoliosis curve of 90° or a stiff curve of lesser degrees in a growing child that made seating and nursing care challenging. The need for anterior release prior to posterior fusion was determined based on flexibility of the curve on clinical examination. No anterior fusions were preformed to prevent crankshafting. Anterior release and posterior spinal fusion were staged by one week in four patients, and it was done in a single stage in one patient. Children under 5 years were considered for short fusions with the goal of extending the fusion closer to growth completion. In two patients who were younger than 5 years, only the primary curve was fused to allow for growth, and subsequently, the fusion was extended.
The unit rod instrumentation was used in all patients with pelvic fixation to correct pelvic obliquity. Proximally, instrumentation was extended to include T2 to C7. This was to prevent proximal sagittal decompensation.
Statistical analysis Both categorical and continuous variables were summarized using frequency and percentage as well as standard deviation or median as appropriate, respectively. Prior to hypothesis testing, a normality test was performed to assess the distribution and shape of the data. To determine whether or not surgery was effective in maintaining correction, repeated measure analysis of variance (RANOVA) with a post-hoc Bonferroni pairwise comparison was used. Kaplan-Meier graphic method was used to illustrate the survival experience. All tests were two-tailed, and the significance level was < 0.05. We used SPSS version 17.0 (Chicago, Illinois) and STATA version 12.0 (STATA, College Station, TX) to analyze the data.
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Results Demographics Thirty-three patients (19 boys and 14 girls) met the inclusion criteria forming the cohort for long-term outcome (Table 1). The mean follow-up was 9.8 ± 2.6 years. The mean radiographic follow-up was 8.2 ± 3.7 years. The mean preoperative BMI was 16.4 ± 4.2. The mean increase in height based on forearm measurement was 24.7 ± 12.7 centimeters (Table 1). All patients were quadriplegic. Thirty-one patients (94%) were GMFCS level V and two (6%) were GMFCS level IV. Ninety-four percent of the children had severe mental retardation, and the remaining 6% had moderate mental retardation. All patients in this series were physiologically compromised due to comorbidities (Table 2).
Curve and surgery characteristics Twenty-six (79%) patients had a single curve, and the rest had double curves. The average number of vertebrae involved in the curve was 9 (range, 5–14). The curve apex was thoracic, thoracolumbar, and lumbar in 10 (30.3%), 13 (39.4%), and 10 (30.3%) patients, respectively. Eighty-five percent of children had posterior only surgery. The instrumentation extended from pelvis to T1 in 28 patients (85%), to T2 in three (9%), and to C7 in two patients (6%). The hospital stay and intraoperative parameters of whole cohort as well as group-wise comparison of patients with posterior-only surgery and those with anterior and posterior surgeries were similar (Table 3).
Outcome of surgery The mean Cobb angle correction was 64° (range, 34°–98°), P < 0.0001. The mean pelvic obliquity correction was 15° ± 9°, P < 0.0001. There was minimal loss of Cobb angle and pelvic obliquity at follow-up (Figure 1; Table 4). The postoperative sagittal profile was maintained at final follow-up; at follow-up, mean thoracic kyphosis was 31° ± 9° and mean lumbar lordosis was 42° ± 8° (Table 4).
Complications
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Major intraoperative complications included pneumothorax in one patient and hydropneumothorax in one patient (Table 5). Pancreatitis was seen in 24% of our cohort in the immediate postoperative period, which prolonged their ICU stay and hospital stay. The presence of pancreatitis was defined based on the elevations of serum amylase and lipase, ultrasonography of abdomen, and clinical examination for signs of abdominal distension or muscle spasms, with epigastric pain and left upper-quadrant tenderness. Draining lumbar hematoma was seen in one patient who needed surgical exploration and drainage. The culture was negative in this patient. There was a wound breakdown over prominent proximal implant in one patient two months post-surgery. Irrigation and debridement of the wound and exchange of a cross connector for unit rod were done. The symptomatic upper portion of the implant was removed seven years after index surgery in this patient. Another patient developed symptomatic bursa over prominent proximal implant necessitating removal of the proximal part two years later. This patient subsequently developed proximal junctional kyphosis. Deep wound infection was seen in one patient in the early postoperative period. This was treated with appropriate antibiotics and exploration and debridement. The wound healed without any sequelae and did not require implant removal.
Mortality Eleven of 39 patients (28.2%) died after mean follow-up of 5.6 ± 3.9 years (range, 1.1 to 12.1 years). There were no intraoperative deaths. Six patients died between 1 and 5 years after surgery, three died between 5 and 10 years, and two died between 10 and 15 years after surgery. The Kaplan-Meier survival estimate (Figure 2) illustrates the proportion survival in 42 patients who were the intitial population. The statistical survival estimate is for 50% survival 15 years after spinal fusion (figure 2).
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Discussion Scoliosis in children with CP usually progresses during peak height velocity. 6, 7 However, in a small subset of children, it develops and progresses early necessitating earlier treatment. These patients are more severely involved compared with the whole cohort of children with CP who develop scoliosis. 3,4,6 All the patients in the current series were quadriplegic, 97% had seizure disorder, and 27% had tracheostomies. Ninety-four percent of the patients had severe mental retardation. In a cohort of 96 patients with quadriplegic CP, Edebol-Tysk et al2 reported the incidence of severe MR and seizure disorder to be 90% and 100%, respectively. Gastrointestinal manifestations are common in CP due to oral-motor problems and disorders of gastric motility. 16,17 Eighty-eight percent of our patients had gastrostomy feeding tubes for nutritional support, and 64% had GERD.
Unit-rod instrumentation achieves simultaneous correction of Cobb angle and pelvic obliquity and maintains this correction at follow-up.18-20 In the current series, we achieved a curve correction of 75% postoperatively, and at follow-up, the mean loss of correction was 3°. With similar instrumentation technique, mean postoperative correction was found to range from 47% to 81%. 10,11,18-21 Watanabe et al22 reported the postoperative satisfaction rate to be associated with percentage correction of major Cobb angle. The pelvic obliquity correction was 78% and loss of correction at follow-up was less than 10%. Pelvic obliquity correction is essential for proper seating balance in this nonambulatory patient population. The reported pelvic obliquity correction in literature ranged from 47% to 82%.18,21
Despite risk of crankshaft phenomenon reported in this age group with posterior only surgery,23,24 we did not observe this phenomenon in the 85% of our patients who had posterior only surgery. Numerous studies have shown that the rigidity of fixation systems might confer protection against this phenomenon. 10,11,18,20,25
Surgical treatment of neuromuscular scoliosis in this population of children with multiple medical problems and severe physical impairment is a major operative undertaking with significant risk of complications. In the early postoperative period, 24% of our patients had pancreatitis, which prolonged their ICU and hospital stays. In their series of 355 patients with CP who underwent spinal fusion for scoliosis, Borkhuu et al26 reported a 30.1%
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prevalence of pancreatitis. They reported GERD and reactive airway disease to be important predictors of postoperative pancreatitis. More than half of our patients had GERD and respiratory system involvement (Table 2).
Deep wound infection was seen in 3% of our patients. In a multicenter study involving 157 patients with CP, Sponseller et al27 reported the rate of deep infection to be 6%; the overall infection rate was 10%. Similarly, in a series of 172 patients instrumented with unit rods, Szoke et al28 reported deep wound infection in 4.1% of patients (overall infection rate was 8.7%). In another large series of spinal fusions in neuromuscular scoliosis treated with Luque-Galveston technique (74 of 93 patients had CP), Lonstein et al21 reported a 1.1% prevalence of deep wound infection. Based on this review, the prevalence of infections in our early onset cohort was similar to published data for spine fusion for scoliosis in children with CP.
The optimal treatment for EOS is yet to be determined. A growth-preserving technique like growing rods may be an attractive alternative in skeletally immature patients because of preservation of growth of thoracic cage and lung volume.29 However, the risks associated with multiple surgeries for repeated lengthenings must be taken with caution, especially in physiologically compromised patients like those in the current series. In the multicenter study on growing rods for EOS in patients with CP, McElroy et al30 reported a 30% prevalence of deep wound infection compared to 3% in the current series. Three of the eight patients who had deep infection needed instrumentation removal in this study. Prominence of implant was the only instrumentation-related complication in the current series, which was possibly because of low, lean body mass. Higher prevalence of implant-related complications was noted in the growing rods group30; this included rod fracture, rod exchange, anchor dislodgement, and revision.
With the overall mortality of 28.2%, this patient population did experience a higher mortality rate than the children fused at an older age, but this is most likely because of the more medically compromised and greater impairment level of the early onset group compared to the older group. We found no evidence to suggest that it was due to the early fusion. Ambulation potential and severity of neurologic involvement have been found to be two independent predictors of mortality in patients with CP.31,32 Two regional-registry-based studies have reported the deaths in quadriplegic CP population to be between 25% and 26%. 31,32 In their series of 288 patients with CP who underwent
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spinal fusion for scoliosis, Tsirikos et al33 reported mortality of 12.5%: three deaths were perioperative, and the mean survival time for the remaining patients was 4.3 years.
Despite the strength of our findings, there are a few limitations. First, this was a retrospective review, which has a tendency to introduce selection and information biases. We tried to be accurate in the data retrieval process by thoroughly examining information from our medical records as well as re-measuring the radiographic parameters used in this study. Secondly, the sample size was small to draw any inference. Thirdly, we did not collect any data prospectively to evaluate quality of life, functional or caregiver outcome measures due to difficulties associated with obtaining data in in this population over a long follow up period. . Lastly, our survival analysis was based on variable survival time with differences in survival experience of our cohort.
In summary, this long-term outcome of spinal fusion for EOS in severely involved children with CP showed unitrod instrumentation was effective in correcting and maintaining scoliosis and pelvic obliquity. Complication rates were similar to spinal fusion in older children with CP. We found no identifiable negative long-term impact of early spine fusion. Based on a comparison with one previous published series of early onset scoliosis,30 the complication risks, especially deep wound infection and instrumentation-related complications, were less with early fusion than with growing-rod constructs.
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References 1. Porter D, Michael S, Kirkwood C. Is there a relationship between preferred posture and positioning in early life and the direction of subsequent asymmetrical postural deformity in non ambulant people with cerebral palsy? Child Care Health Dev. 2008;34:635-641. 2. Edebol-Tysk K, Hagberg B, Hagberg G. Epidemiology of spastic tetraplegic cerebral palsy in Sweden. II. Prevalence, birth data and origin. Neuropediatrics. 1989;20:46-52. 3. Madigan RR, Wallace SL. Scoliosis in the institutionalized cerebral palsy population. Spine. 1981;6:583-590. 4. Persson-Bunke M, Hägglund G, Lauge-Pedersen H, et al. Scoliosis in a total population of children with cerebral palsy. Spine. 2012;37:E708-E713. 5. Robson P. The prevalence of scoliosis in adolescents and young adults with cerebral palsy. Dev Med Child Neurol. 1968;10:447-452. 6. Saito N, Ebara S, Ohotsuka K, et al. Natural history of scoliosis in spastic cerebral palsy. Lancet. 1998;351:16871692. 7. Miller A, Temple T, Miller F. Impact of orthoses on the rate of scoliosis progression in children with cerebral palsy. J Pediatr Orthop. 1996;16:332-335. 8. Majd ME, Muldowny DS, Holt RT. Natural history of scoliosis in the institutionalized adult cerebral palsy population. Spine. 1997;22:1461-1466. 9. Kalen V, Conklin MM, Sherman FC. Untreated scoliosis in severe cerebral palsy. J Pediatr Orthop. 1992;12:337340. 10. Westerlund LE, Gill SS, Jarosz TS, et al. Posterior-only unit rod instrumentation and fusion for neuromuscular scoliosis. Spine. 2001;26:1984-1989. 11. Yazici M, Asher MA, Hardacker JW. The safety and efficacy of Isola-Galveston instrumentation and arthrodesis in the treatment of neuromuscular spinal deformities. J Bone Joint Surg Am. 2000;82:524-543. 12. Miller F, Koreska J. Height measurement of patients with neuromuscular disease and contractures. Dev Med Child Neurol. 1992;34:55-60. 13. Cobb JR. Outline for the study of scoliosis. In: JW Edwards, ed. American Academy of Orthopaedic Surgeons, ed. Instructional Course Lectures. Ann Arbor, MI: AAOS; 1948:261-275.
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14. Gaine WJ, Lim J, Stephenson W, et al. Progression of scoliosis after spinal fusion in Duchenne's muscular dystrophy. J Bone Joint Surg Br. 2004;86:550-555. 15. Lenke LG, Betz RR, Harms J, et al. Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis. J Bone Joint Surg Am. 2001;83-A:1169-1181. 16. Del Giudice E, Staiano A, Capano G, et al. Gastrointestinal manifestations in children with cerebral palsy. Brain Dev. 1999;21:307-311. 17. Sullivan PB, Juszczak E, Bachlet AM, et al. Gastrostomy tube feeding in children with cerebral palsy: a prospective, longitudinal study. Dev Med Child Neurol. 2005;47:77-85. 18. Dias RC, Miller F, Dabney K, et al. Surgical correction of spinal deformity using a unit rod in children with cerebral palsy. J Pediatr Orthop. 1996;16:734-740. 19. Maloney WJ, Rinsky LA, Gamble JG. Simultaneous correction of pelvic obliquity, frontal plane, and sagittal plane deformities in neuromuscular scoliosis using a unit rod with segmental sublaminar wires: a preliminary report. J Pediatr Orthop. 1990;10:742-749. 20. Tsirikos AI, Lipton G, Chang WN, et al. Surgical correction of scoliosis in pediatric patients with cerebral palsy using the unit rod instrumentation. Spine. 2008;33:1133-1140. 21. Lonstein JE, Koop SE, Novachek TF, et al. Results and complications after spinal fusion for neuromuscular scoliosis in cerebral palsy and static encephalopathy using luque galveston instrumentation: experience in 93 patients. Spine. 2012;37:583-591. 22. Watanabe K, Lenke LG, Daubs MD, et al. Is spine deformity surgery in patients with spastic cerebral palsy truly beneficial?: a patient/parent evaluation. Spine. 2009;34:2222-2232. 23. Dubousset J, Herring JA, Shufflebarger H. The crankshaft phenomenon. J Pediatr Orthop. 1989;9:541-550. 24. Sanders JO, Herring JA, Browne RH. Posterior arthrodesis and instrumentation in the immature (Risser-grade-0) spine in idiopathic scoliosis. J Bone Joint Surg Am. 1995;77:39-45. 25. Burton DC, Asher MA, Lai SM. Scoliosis correction maintenance in skeletally immature patients with idiopathic scoliosis. Is anterior fusion really necessary? Spine. 2000;25:61-68. 26. Borkhuu B, Nagaraju D, Miller F, et al. Prevalence and risk factors in postoperative pancreatitis after spine fusion in patients with cerebral palsy. J Pediatr Orthop. 2009;29:256-262.
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27. Sponseller PD, Shah SA, Abel MF, et al. Infection rate after spine surgery in cerebral palsy is high and impairs results: multicenter analysis of risk factors and treatment. Clin Orthop Relat Res. 2010;468:711-716. 28. Szöke G, Lipton G, Miller F, et al. Wound infection after spinal fusion in children with cerebral palsy. J Pediatr Orthop. 1998;18:727-733. 29. Akbarnia BA, Marks DS, Boachie-Adjei O, et al. Dual growing rod technique for the treatment of progressive early-onset scoliosis: a multicenter study. Spine. 2005;30:S46-S57. 30. McElroy MJ, Sponseller PD, Dattilo JR, et al. Growing rods for the treatment of scoliosis in children with cerebral palsy: a critical assessment. Spine. 2012;37:E1504-E1510. 31. Evans PM, Evans SJ, Alberman E. Cerebral palsy: why we must plan for survival. Arch Dis Child. 1990;65:1329-1333. 32. Hutton JL, Pharoah PO. Life expectancy in severe cerebral palsy. Arch Dis Child. 2006;91:254-258. 33. Tsirikos AI, Chang WN, Dabney KW, et al. Life expectancy in pediatric patients with cerebral palsy and neuromuscular scoliosis who underwent spinal fusion. Dev Med Child Neurol. 2003;45:677-682.
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Figure legends Figure 1: Radiographs of 8.4-years-old girl with preoperative thoracolumbar scoliosis of 83° with severe pelvic obliquity (A) and 90° kyphosis (B). (C and D) Immediate postoperative radiographs show excellent correction of Cobb angle and pelvic obliquity (E and F). Radiographs at 11 years follow-up show maintenance of postoperative correction. Figure 2: Kaplan-Meier survival estimate showing survival function. Projected survivorship dropped to approximately 60% at 12 years postoperative.
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Table 1. Demographics Variable
Mean
SD
Range
Age at surgery (years)
8.3
1.4
4.4–9.9
Follow-up (years)
9.8
2.6
5.5–15.8
Initial (at surgery)
22
7
10–37
Final follow-up
36
9
19–63
Initial (at surgery)
115
11
92–147
Final follow-up
140
12
121–163
16.4
4.2
10–27.2
Weight (Kg)
Height (centimeters)
Body mass index (Initial)
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Table 2. Comorbidities Comorbidities
Frequency
Percentage (%)
Seizures
32
97
Gastric-tube feeding
29
88
Gastroesophageal reflux disease (GERD)
21
64
Nissen fundoplication (NF)
14
66.7
No NF
7
33.3
Respiratory system involvement*
17
52
Restrictive lung disease
6
35.3
Asthma/reactive airway disease
9
53
Recurrent aspiration pneumonia
6
35.3
Tracheostomy
9
27
Ventilator dependent
5
55.6
Not ventilator dependent
4
44.4
*Some patients had multiple respiratory problems; total count of problems does not correspond to the number of patients who had them
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Table 3. Duration of hospital stay and intraoperative parameters Variable
All cohort (n = 33)
Posterior only (n = 28)
Anterior and posterior (n = 5)
Median
Range
Median
Range
Median
Range
Hospital stay (days)
18
8–48
16
8–45
27
19–48
ICU stay (days)
5
3–35
5
3–19
11
9–35
Estimated blood loss (ml)
1935
300–4700
1750
300–4700
1640
850–2490
Blood volume loss
1.3
0.1–3.6
1.3
0.1–3.2
1.3
0.7–3.6
Operation time (minutes)
281
138–563
244
138–420
445
350–563
Note: Summary statistics using median due to non-normal distribution of variables
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Table 4. Outcome of Surgery Variable
Mean
SD
Range
Cobb angles (degrees)
f (df)** 377.6 (1.1)
P§ < 0.0001
Preoperative
85
17
54–118
Postoperative
21
13
0–40
Follow-up
24
13
0–43
*Cobb angle correction (degrees)
64
17
34–98
-
< 0.0001
*Loss of Cobb angle correction
3
4
0–15
-
-
74.9 (1.1)
< 0.0001
(degrees) Pelvic obliquity (degrees) Preoperative
18
10
5–45
Postoperative
4
3
0–15
Follow-up
5
4
0–16
*Pelvic obliquity correction
15
9
1–35
-
< 0.001
1.4
2.4
-3–10
-
-
11.3 (1.0)
0.003
3.2 (1.0)
0.09
(degrees) *Loss of pelvic obliquity correction (degrees) Thoracic kyphosis (degrees) Preoperative
49
23
10–103
Postoperative
31
7
16–50
Follow up
31
9
18–60
Lumbar lordosis (degrees) Preoperative
31
32
-64–74
Postoperative
41
7
20–58
Follow-up
42
8
20–58
*Results based on Bonferroni pairwise comparison; **f (df), ratio of variance (degree of freedom); §P, probability (set at 5%)
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Table 5. Complications of surgery Complications
Frequency
Percentage (%)
Pneumothorax
1
3
Hydropneumothorax
1
3
Pancreatitis
8
24
Cholangitis
1
3
Septicemia
1
3
Respiratory failure
2
6
Deep wound infection
1
3
Lumbar hematoma
1
3
Wound breakdown over prominent proximal
1
3
Decubitus ulcer
2
6
Implant prominence: proximal
2
6
Implant prominence: distal
1
3
Proximal junctional kyphosis
1
3
Intraoperative
Early (< 3 months)
implant Late (> 3 months)
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The Long-term Outcome of Early Spine Fusion for Scoliosis in Children with Cerebral Palsy
Running title: Early Spine Fusion in Cerebral Palsy
Prakash Sitoula, MD; Laurens Holmes Jr., PhD, DrPH; Julieanne Sees, DO; Kenneth Rogers, PhD, ATC; Kirk Dabney, MD; Freeman Miller, MD Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE 19899, USA
Corresponding author: Freeman Miller, MD Department of Orthopedics Nemours/Alfred I. duPont Hospital for Children P.O. Box 269 Wilmington, DE 19899 Phone: 302-651-5921 Fax: 302-651-5951 Email: [email protected]
Conflicts of Interest and Source of Funding: None
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The Long-term Outcome of Early Spine Fusion for Scoliosis in Children with Cerebral Palsy
Abstract Study Design: Retrospective review of radiographs and charts (case-only) Objective: The aim of this study was to describe the long-term outcomes of spine fusion for neuromuscular scoliosis in children < 10 years of age with cerebral palsy (CP). Summary of Background Data: Severely involved children with CP may develop early onset scoliosis. The outcome of spine fusion is not clear and there are no studies focused on spine fusion in this young patient population. Methods: This is a retrospective review of 33 children who underwent spine fusion with unit rod instrumentation between 1989 and 2006 for CP neuromuscular scoliosis, aged < 10 years at spine fusion, and with follow-up > 5 years. Demographic, medical, and radiographic data were retrospectively assessed. RANOVA and Kaplan-Meier survival estimates were used for data assessment. Results: 33 of 42 patients who underwent spine fusion in this period, 19 boys and 14 girls, met the inclusion criteria. Out of 9 patients who were excluded, 3 were lost to follow up and remaining 6 died within 5 years of surgery. Mean age at surgery was 8.3 years (range, 4.4–9.9). Mean follow-up was 9.8 years (range, 5.5–15.8). Gross motor function classification system level was V in 31 patients and IV in 2 patients. Thirty-one patients (94%) had seizure disorder, 29 patients (88%) had gastric feeding tubes, and 9 patients (27%) had tracheostomy tubes. 85% of the patients had posterior only surgery. Mean Cobb angles preoperative, immediately postoperative, and at final follow-up were 85°, 21°, and 24°, respectively. Mean postoperative pelvic obliquity correction was 15° ± 9°, P < 0.001. At final followup, there was no significant change from the postoperative measurements. Complications included one deep wound infection and 10 other problems. Eleven patients (28.2%) died after a mean follow-up of 5.6 ± 3.8 years. Conclusion: In our cohort with early onset neuromuscular scoliosis, spine fusion was associated with minimal short and long-term morbidity, but there 28% mortality at ten years follow-up and 50% predicted mortality at 15 years. Key Words: early onset scoliosis, neuromuscular scoliosis, quadriplegia, gross motor function classification system (GMFCS), co-morbidities, unit rod, pelvic obliquity, Cobb angle
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Introduction Cerebral palsy (CP) is a static encephalopathy due to insult to an immature brain. The musculoskeletal manifestations are secondary and often progressive due to cumulative effect of spasticity, asymmetric antagonistic muscle involvement, and growth. Scoliosis is a common orthopedic condition seen in CP that develops secondary to poor trunk balance.1 The overall incidence of scoliosis in CP varies from 15 to 25% and the incidence in quadriplegics ranges from 67 to 75%.2-6 The occurrence of scoliosis in CP is directly related to severity of neurologic involvement3,4,6 and is inversely related to ambulation potential.3,6
Curve progression in CP tends to correspond with peak height velocity. 7 This often complicates patient care with hygiene, feeding, and wheelchair transfers. This may also have a negative impact on cardiopulmonary and gastrointestinal functions.8 Pelvic obliquity develops and worsens with curve progression, leading to loss of seating balance8,9 and making frequent wheelchair readjustments necessary. Bracing may have a limited role in supported sitting, but it does not prevent curve progression in quadriplegic CP.7
High and rapid curve progression leads to seating problems that become progressively more difficult to manage, necessitating surgical stabilization of the spine. Currently available surgical options include immediate spinal deformity correction and fusion or utilization of some form of growth-sparing procedures like growing rods. There are a number of studies that have included small numbers of patients younger than 10 years in their cohort; however, there are no studies focused on spine fusion in this isolated young patient population. 10,11 The aim of this study was to assess long-term (follow-up > 5 years) outcome of spine fusion in early onset scoliosis (EOS) in children with CP.
Methods After an IRB approval, we retrospectively reviewed 42 patients with CP who underwent spinal fusion for neuromuscular scoliosis before age 10 years between 1989 and 2006. All patients were treated by two senior authors (FM and KD).
Patient selection
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Inclusion criteria were CP with neuromuscular scoliosis, age less than 10 years at spine fusion, and postoperative follow-up more than 5 years. Thirty-three children (19 boys and 14 girls) met our inclusion criteria and formed the cohort for this study. Nine patients were excluded from long-term aspect of the study: three were lost to follow-up, and six died after a mean follow-up of 2.6 ± 1.1 years. Therefore, 39 out of 42 patients were followed up to their death or more than 5 years. These 39 patients were considered for evaluation of mortality as indicated in the KaplanMeier Survival Estimate.
The medical records were reviewed for patient age, gender, diagnosis, geographic pattern of involvement, mental status, ambulation potential, and gross motor function classification system (GMFCS) level. All patients in the current series had multisystem involvement and the comorbidities included seizure disorder, gastrointestinal issues (gastrostomy-tube feeding and gastroesophageal reflux disease [GERD] with or without Nissen fundoplication), and respiratory problems (obstructive, restrictive, and reactive airway diseases; asthma; recurrent aspiration pneumonitis; and tracheostomy with or without ventilator dependence). Operation time, hospital duration, and ICU stays were also recorded. Estimated blood loss (EBL) during surgery was recorded in milliliters and as blood volume loss (EBL/70x body weight in kilograms). The complications were recorded as intraoperative, early (< 3 months after surgery), and late (> 3 months after surgery). The heights (measured by arm-board measurements12) and weights were recorded preoperatively and at final follow-up. The preoperative body mass index (BMI) was calculated with the initial height and weight. The last clinic visit on record was taken as the final clinical follow-up.
Radiographic evaluation Spinal radiographs (anteroposterior and lateral views) were taken with the patient seated, and Cobb angle, thoracic kyphosis (T5–12), and lumbar lordosis (L1–5) were measured by the Cobb method.13 In the presence of double curves, the larger of the two curves was taken into consideration for all measurement purposes. Pelvic obliquity was measured on an AP spinal radiograph as an angle formed by a line connecting the highest points on the iliac crests with the horizontal.14 The location of curve apex was defined as thoracic (apex between T2 and T11–12 disc), thoracolumbar (apex between T12 and L1), and lumbar (apex between L1–L2 disc and L4).15 All radiographs were measured by the same observer. In some patients, clinical follow-up was longer than the radiographic follow-up because radiographs were not obtained at every clinic visit.
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Surgical indications and technique The treatment protocol for scoliosis in children with CP included using wheelchair support and propped-up sitting orthotics in the growing child until the scoliosis approached 90° or developed severe stiffness making adaptive seating and nursing increasingly more difficult. Therefore, surgical indication was for scoliosis curve of 90° or a stiff curve of lesser degrees in a growing child that made seating and nursing care challenging. The need for anterior release prior to posterior fusion was determined based on flexibility of the curve on clinical examination. No anterior fusions were preformed to prevent crankshafting. Anterior release and posterior spinal fusion were staged by one week in four patients, and it was done in a single stage in one patient. Children under 5 years were considered for short fusions with the goal of extending the fusion closer to growth completion. In two patients who were younger than 5 years, only the primary curve was fused to allow for growth, and subsequently, the fusion was extended.
The unit rod instrumentation was used in all patients with pelvic fixation to correct pelvic obliquity. Proximally, instrumentation was extended to include T2 to C7. This was to prevent proximal sagittal decompensation.
Statistical analysis Both categorical and continuous variables were summarized using frequency and percentage as well as standard deviation or median as appropriate, respectively. Prior to hypothesis testing, a normality test was performed to assess the distribution and shape of the data. To determine whether or not surgery was effective in maintaining correction, repeated measure analysis of variance (RANOVA) with a post-hoc Bonferroni pairwise comparison was used. Kaplan-Meier graphic method was used to illustrate the survival experience. All tests were two-tailed, and the significance level was < 0.05. We used SPSS version 17.0 (Chicago, Illinois) and STATA version 12.0 (STATA, College Station, TX) to analyze the data.
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Results Demographics Thirty-three patients (19 boys and 14 girls) met the inclusion criteria forming the cohort for long-term outcome (Table 1). The mean follow-up was 9.8 ± 2.6 years. The mean radiographic follow-up was 8.2 ± 3.7 years. The mean preoperative BMI was 16.4 ± 4.2. The mean increase in height based on forearm measurement was 24.7 ± 12.7 centimeters (Table 1). All patients were quadriplegic. Thirty-one patients (94%) were GMFCS level V and two (6%) were GMFCS level IV. Ninety-four percent of the children had severe mental retardation, and the remaining 6% had moderate mental retardation. All patients in this series were physiologically compromised due to comorbidities (Table 2).
Curve and surgery characteristics Twenty-six (79%) patients had a single curve, and the rest had double curves. The average number of vertebrae involved in the curve was 9 (range, 5–14). The curve apex was thoracic, thoracolumbar, and lumbar in 10 (30.3%), 13 (39.4%), and 10 (30.3%) patients, respectively. Eighty-five percent of children had posterior only surgery. The instrumentation extended from pelvis to T1 in 28 patients (85%), to T2 in three (9%), and to C7 in two patients (6%). The hospital stay and intraoperative parameters of whole cohort as well as group-wise comparison of patients with posterior-only surgery and those with anterior and posterior surgeries were similar (Table 3).
Outcome of surgery The mean Cobb angle correction was 64° (range, 34°–98°), P < 0.0001. The mean pelvic obliquity correction was 15° ± 9°, P < 0.0001. There was minimal loss of Cobb angle and pelvic obliquity at follow-up (Figure 1; Table 4). The postoperative sagittal profile was maintained at final follow-up; at follow-up, mean thoracic kyphosis was 31° ± 9° and mean lumbar lordosis was 42° ± 8° (Table 4).
Complications
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Major intraoperative complications included pneumothorax in one patient and hydropneumothorax in one patient (Table 5). Pancreatitis was seen in 24% of our cohort in the immediate postoperative period, which prolonged their ICU stay and hospital stay. The presence of pancreatitis was defined based on the elevations of serum amylase and lipase, ultrasonography of abdomen, and clinical examination for signs of abdominal distension or muscle spasms, with epigastric pain and left upper-quadrant tenderness. Draining lumbar hematoma was seen in one patient who needed surgical exploration and drainage. The culture was negative in this patient. There was a wound breakdown over prominent proximal implant in one patient two months post-surgery. Irrigation and debridement of the wound and exchange of a cross connector for unit rod were done. The symptomatic upper portion of the implant was removed seven years after index surgery in this patient. Another patient developed symptomatic bursa over prominent proximal implant necessitating removal of the proximal part two years later. This patient subsequently developed proximal junctional kyphosis. Deep wound infection was seen in one patient in the early postoperative period. This was treated with appropriate antibiotics and exploration and debridement. The wound healed without any sequelae and did not require implant removal.
Mortality Eleven of 39 patients (28.2%) died after mean follow-up of 5.6 ± 3.9 years (range, 1.1 to 12.1 years). There were no intraoperative deaths. Six patients died between 1 and 5 years after surgery, three died between 5 and 10 years, and two died between 10 and 15 years after surgery. The Kaplan-Meier survival estimate (Figure 2) illustrates the proportion survival in 42 patients who were the intitial population. The statistical survival estimate is for 50% survival 15 years after spinal fusion (figure 2).
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Discussion Scoliosis in children with CP usually progresses during peak height velocity. 6, 7 However, in a small subset of children, it develops and progresses early necessitating earlier treatment. These patients are more severely involved compared with the whole cohort of children with CP who develop scoliosis. 3,4,6 All the patients in the current series were quadriplegic, 97% had seizure disorder, and 27% had tracheostomies. Ninety-four percent of the patients had severe mental retardation. In a cohort of 96 patients with quadriplegic CP, Edebol-Tysk et al2 reported the incidence of severe MR and seizure disorder to be 90% and 100%, respectively. Gastrointestinal manifestations are common in CP due to oral-motor problems and disorders of gastric motility. 16,17 Eighty-eight percent of our patients had gastrostomy feeding tubes for nutritional support, and 64% had GERD.
Unit-rod instrumentation achieves simultaneous correction of Cobb angle and pelvic obliquity and maintains this correction at follow-up.18-20 In the current series, we achieved a curve correction of 75% postoperatively, and at follow-up, the mean loss of correction was 3°. With similar instrumentation technique, mean postoperative correction was found to range from 47% to 81%. 10,11,18-21 Watanabe et al22 reported the postoperative satisfaction rate to be associated with percentage correction of major Cobb angle. The pelvic obliquity correction was 78% and loss of correction at follow-up was less than 10%. Pelvic obliquity correction is essential for proper seating balance in this nonambulatory patient population. The reported pelvic obliquity correction in literature ranged from 47% to 82%.18,21
Despite risk of crankshaft phenomenon reported in this age group with posterior only surgery,23,24 we did not observe this phenomenon in the 85% of our patients who had posterior only surgery. Numerous studies have shown that the rigidity of fixation systems might confer protection against this phenomenon. 10,11,18,20,25
Surgical treatment of neuromuscular scoliosis in this population of children with multiple medical problems and severe physical impairment is a major operative undertaking with significant risk of complications. In the early postoperative period, 24% of our patients had pancreatitis, which prolonged their ICU and hospital stays. In their series of 355 patients with CP who underwent spinal fusion for scoliosis, Borkhuu et al26 reported a 30.1%
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prevalence of pancreatitis. They reported GERD and reactive airway disease to be important predictors of postoperative pancreatitis. More than half of our patients had GERD and respiratory system involvement (Table 2).
Deep wound infection was seen in 3% of our patients. In a multicenter study involving 157 patients with CP, Sponseller et al27 reported the rate of deep infection to be 6%; the overall infection rate was 10%. Similarly, in a series of 172 patients instrumented with unit rods, Szoke et al28 reported deep wound infection in 4.1% of patients (overall infection rate was 8.7%). In another large series of spinal fusions in neuromuscular scoliosis treated with Luque-Galveston technique (74 of 93 patients had CP), Lonstein et al21 reported a 1.1% prevalence of deep wound infection. Based on this review, the prevalence of infections in our early onset cohort was similar to published data for spine fusion for scoliosis in children with CP.
The optimal treatment for EOS is yet to be determined. A growth-preserving technique like growing rods may be an attractive alternative in skeletally immature patients because of preservation of growth of thoracic cage and lung volume.29 However, the risks associated with multiple surgeries for repeated lengthenings must be taken with caution, especially in physiologically compromised patients like those in the current series. In the multicenter study on growing rods for EOS in patients with CP, McElroy et al30 reported a 30% prevalence of deep wound infection compared to 3% in the current series. Three of the eight patients who had deep infection needed instrumentation removal in this study. Prominence of implant was the only instrumentation-related complication in the current series, which was possibly because of low, lean body mass. Higher prevalence of implant-related complications was noted in the growing rods group30; this included rod fracture, rod exchange, anchor dislodgement, and revision.
With the overall mortality of 28.2%, this patient population did experience a higher mortality rate than the children fused at an older age, but this is most likely because of the more medically compromised and greater impairment level of the early onset group compared to the older group. We found no evidence to suggest that it was due to the early fusion. Ambulation potential and severity of neurologic involvement have been found to be two independent predictors of mortality in patients with CP.31,32 Two regional-registry-based studies have reported the deaths in quadriplegic CP population to be between 25% and 26%. 31,32 In their series of 288 patients with CP who underwent
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spinal fusion for scoliosis, Tsirikos et al33 reported mortality of 12.5%: three deaths were perioperative, and the mean survival time for the remaining patients was 4.3 years.
Despite the strength of our findings, there are a few limitations. First, this was a retrospective review, which has a tendency to introduce selection and information biases. We tried to be accurate in the data retrieval process by thoroughly examining information from our medical records as well as re-measuring the radiographic parameters used in this study. Secondly, the sample size was small to draw any inference. Thirdly, we did not collect any data prospectively to evaluate quality of life, functional or caregiver outcome measures due to difficulties associated with obtaining data in in this population over a long follow up period. . Lastly, our survival analysis was based on variable survival time with differences in survival experience of our cohort.
In summary, this long-term outcome of spinal fusion for EOS in severely involved children with CP showed unitrod instrumentation was effective in correcting and maintaining scoliosis and pelvic obliquity. Complication rates were similar to spinal fusion in older children with CP. We found no identifiable negative long-term impact of early spine fusion. Based on a comparison with one previous published series of early onset scoliosis,30 the complication risks, especially deep wound infection and instrumentation-related complications, were less with early fusion than with growing-rod constructs.
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References 1. Porter D, Michael S, Kirkwood C. Is there a relationship between preferred posture and positioning in early life and the direction of subsequent asymmetrical postural deformity in non ambulant people with cerebral palsy? Child Care Health Dev. 2008;34:635-641. 2. Edebol-Tysk K, Hagberg B, Hagberg G. Epidemiology of spastic tetraplegic cerebral palsy in Sweden. II. Prevalence, birth data and origin. Neuropediatrics. 1989;20:46-52. 3. Madigan RR, Wallace SL. Scoliosis in the institutionalized cerebral palsy population. Spine. 1981;6:583-590. 4. Persson-Bunke M, Hägglund G, Lauge-Pedersen H, et al. Scoliosis in a total population of children with cerebral palsy. Spine. 2012;37:E708-E713. 5. Robson P. The prevalence of scoliosis in adolescents and young adults with cerebral palsy. Dev Med Child Neurol. 1968;10:447-452. 6. Saito N, Ebara S, Ohotsuka K, et al. Natural history of scoliosis in spastic cerebral palsy. Lancet. 1998;351:16871692. 7. Miller A, Temple T, Miller F. Impact of orthoses on the rate of scoliosis progression in children with cerebral palsy. J Pediatr Orthop. 1996;16:332-335. 8. Majd ME, Muldowny DS, Holt RT. Natural history of scoliosis in the institutionalized adult cerebral palsy population. Spine. 1997;22:1461-1466. 9. Kalen V, Conklin MM, Sherman FC. Untreated scoliosis in severe cerebral palsy. J Pediatr Orthop. 1992;12:337340. 10. Westerlund LE, Gill SS, Jarosz TS, et al. Posterior-only unit rod instrumentation and fusion for neuromuscular scoliosis. Spine. 2001;26:1984-1989. 11. Yazici M, Asher MA, Hardacker JW. The safety and efficacy of Isola-Galveston instrumentation and arthrodesis in the treatment of neuromuscular spinal deformities. J Bone Joint Surg Am. 2000;82:524-543. 12. Miller F, Koreska J. Height measurement of patients with neuromuscular disease and contractures. Dev Med Child Neurol. 1992;34:55-60. 13. Cobb JR. Outline for the study of scoliosis. In: JW Edwards, ed. American Academy of Orthopaedic Surgeons, ed. Instructional Course Lectures. Ann Arbor, MI: AAOS; 1948:261-275.
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14. Gaine WJ, Lim J, Stephenson W, et al. Progression of scoliosis after spinal fusion in Duchenne's muscular dystrophy. J Bone Joint Surg Br. 2004;86:550-555. 15. Lenke LG, Betz RR, Harms J, et al. Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis. J Bone Joint Surg Am. 2001;83-A:1169-1181. 16. Del Giudice E, Staiano A, Capano G, et al. Gastrointestinal manifestations in children with cerebral palsy. Brain Dev. 1999;21:307-311. 17. Sullivan PB, Juszczak E, Bachlet AM, et al. Gastrostomy tube feeding in children with cerebral palsy: a prospective, longitudinal study. Dev Med Child Neurol. 2005;47:77-85. 18. Dias RC, Miller F, Dabney K, et al. Surgical correction of spinal deformity using a unit rod in children with cerebral palsy. J Pediatr Orthop. 1996;16:734-740. 19. Maloney WJ, Rinsky LA, Gamble JG. Simultaneous correction of pelvic obliquity, frontal plane, and sagittal plane deformities in neuromuscular scoliosis using a unit rod with segmental sublaminar wires: a preliminary report. J Pediatr Orthop. 1990;10:742-749. 20. Tsirikos AI, Lipton G, Chang WN, et al. Surgical correction of scoliosis in pediatric patients with cerebral palsy using the unit rod instrumentation. Spine. 2008;33:1133-1140. 21. Lonstein JE, Koop SE, Novachek TF, et al. Results and complications after spinal fusion for neuromuscular scoliosis in cerebral palsy and static encephalopathy using luque galveston instrumentation: experience in 93 patients. Spine. 2012;37:583-591. 22. Watanabe K, Lenke LG, Daubs MD, et al. Is spine deformity surgery in patients with spastic cerebral palsy truly beneficial?: a patient/parent evaluation. Spine. 2009;34:2222-2232. 23. Dubousset J, Herring JA, Shufflebarger H. The crankshaft phenomenon. J Pediatr Orthop. 1989;9:541-550. 24. Sanders JO, Herring JA, Browne RH. Posterior arthrodesis and instrumentation in the immature (Risser-grade-0) spine in idiopathic scoliosis. J Bone Joint Surg Am. 1995;77:39-45. 25. Burton DC, Asher MA, Lai SM. Scoliosis correction maintenance in skeletally immature patients with idiopathic scoliosis. Is anterior fusion really necessary? Spine. 2000;25:61-68. 26. Borkhuu B, Nagaraju D, Miller F, et al. Prevalence and risk factors in postoperative pancreatitis after spine fusion in patients with cerebral palsy. J Pediatr Orthop. 2009;29:256-262.
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27. Sponseller PD, Shah SA, Abel MF, et al. Infection rate after spine surgery in cerebral palsy is high and impairs results: multicenter analysis of risk factors and treatment. Clin Orthop Relat Res. 2010;468:711-716. 28. Szöke G, Lipton G, Miller F, et al. Wound infection after spinal fusion in children with cerebral palsy. J Pediatr Orthop. 1998;18:727-733. 29. Akbarnia BA, Marks DS, Boachie-Adjei O, et al. Dual growing rod technique for the treatment of progressive early-onset scoliosis: a multicenter study. Spine. 2005;30:S46-S57. 30. McElroy MJ, Sponseller PD, Dattilo JR, et al. Growing rods for the treatment of scoliosis in children with cerebral palsy: a critical assessment. Spine. 2012;37:E1504-E1510. 31. Evans PM, Evans SJ, Alberman E. Cerebral palsy: why we must plan for survival. Arch Dis Child. 1990;65:1329-1333. 32. Hutton JL, Pharoah PO. Life expectancy in severe cerebral palsy. Arch Dis Child. 2006;91:254-258. 33. Tsirikos AI, Chang WN, Dabney KW, et al. Life expectancy in pediatric patients with cerebral palsy and neuromuscular scoliosis who underwent spinal fusion. Dev Med Child Neurol. 2003;45:677-682.
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Figure legends Figure 1: Radiographs of 8.4-years-old girl with preoperative thoracolumbar scoliosis of 83° with severe pelvic obliquity (A) and 90° kyphosis (B). (C and D) Immediate postoperative radiographs show excellent correction of Cobb angle and pelvic obliquity (E and F). Radiographs at 11 years follow-up show maintenance of postoperative correction. Figure 2: Kaplan-Meier survival estimate showing survival function. Projected survivorship dropped to approximately 60% at 12 years postoperative.
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Table 1. Demographics Variable
Mean
SD
Range
Age at surgery (years)
8.3
1.4
4.4–9.9
Follow-up (years)
9.8
2.6
5.5–15.8
Initial (at surgery)
22
7
10–37
Final follow-up
36
9
19–63
Initial (at surgery)
115
11
92–147
Final follow-up
140
12
121–163
16.4
4.2
10–27.2
Weight (Kg)
Height (centimeters)
Body mass index (Initial)
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Table 2. Comorbidities Comorbidities
Frequency
Percentage (%)
Seizures
32
97
Gastric-tube feeding
29
88
Gastroesophageal reflux disease (GERD)
21
64
Nissen fundoplication (NF)
14
66.7
No NF
7
33.3
Respiratory system involvement*
17
52
Restrictive lung disease
6
35.3
Asthma/reactive airway disease
9
53
Recurrent aspiration pneumonia
6
35.3
Tracheostomy
9
27
Ventilator dependent
5
55.6
Not ventilator dependent
4
44.4
*Some patients had multiple respiratory problems; total count of problems does not correspond to the number of patients who had them
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Table 3. Duration of hospital stay and intraoperative parameters Variable
All cohort (n = 33)
Posterior only (n = 28)
Anterior and posterior (n = 5)
Median
Range
Median
Range
Median
Range
Hospital stay (days)
18
8–48
16
8–45
27
19–48
ICU stay (days)
5
3–35
5
3–19
11
9–35
Estimated blood loss (ml)
1935
300–4700
1750
300–4700
1640
850–2490
Blood volume loss
1.3
0.1–3.6
1.3
0.1–3.2
1.3
0.7–3.6
Operation time (minutes)
281
138–563
244
138–420
445
350–563
Note: Summary statistics using median due to non-normal distribution of variables
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Table 4. Outcome of Surgery Variable
Mean
SD
Range
Cobb angles (degrees)
f (df)** 377.6 (1.1)
P§ < 0.0001
Preoperative
85
17
54–118
Postoperative
21
13
0–40
Follow-up
24
13
0–43
*Cobb angle correction (degrees)
64
17
34–98
-
< 0.0001
*Loss of Cobb angle correction
3
4
0–15
-
-
74.9 (1.1)
< 0.0001
(degrees) Pelvic obliquity (degrees) Preoperative
18
10
5–45
Postoperative
4
3
0–15
Follow-up
5
4
0–16
*Pelvic obliquity correction
15
9
1–35
-
< 0.001
1.4
2.4
-3–10
-
-
11.3 (1.0)
0.003
3.2 (1.0)
0.09
(degrees) *Loss of pelvic obliquity correction (degrees) Thoracic kyphosis (degrees) Preoperative
49
23
10–103
Postoperative
31
7
16–50
Follow up
31
9
18–60
Lumbar lordosis (degrees) Preoperative
31
32
-64–74
Postoperative
41
7
20–58
Follow-up
42
8
20–58
*Results based on Bonferroni pairwise comparison; **f (df), ratio of variance (degree of freedom); §P, probability (set at 5%)
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Table 5. Complications of surgery Complications
Frequency
Percentage (%)
Pneumothorax
1
3
Hydropneumothorax
1
3
Pancreatitis
8
24
Cholangitis
1
3
Septicemia
1
3
Respiratory failure
2
6
Deep wound infection
1
3
Lumbar hematoma
1
3
Wound breakdown over prominent proximal
1
3
Decubitus ulcer
2
6
Implant prominence: proximal
2
6
Implant prominence: distal
1
3
Proximal junctional kyphosis
1
3
Intraoperative
Early (< 3 months)
implant Late (> 3 months)
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