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Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up
the surgeon xxx (xxxx) xxx
Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up* a,1 € Norbert Stiel a,1, Jasmin Ozden , Karsten Ridderbusch a, Menard Moritz a, Philip Kunkel b, Amit Gulati c, Christian Hagemann b, Kiril Mladenov a, Ralf Stuecker a, Alexander S. Spiro a,* a
Department of Pediatric Orthopaedic Surgery, Children's Hospital Hamburg-Altona, University Medical Center Hamburg-Eppendorf, Hamburg, Germany b Department of Pediatric Neurosurgery, Children's Hospital Hamburg-Altona, University Medical Center HamburgEppendorf, Hamburg, Germany c Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
article info
abstract
Article history:
Objective: Neuromuscular scoliosis (NMS) is often associated with rapid progressive spinal
Received 26 August 2019
deformities. Indications, when to extend the instrumentation to the pelvis for pelvic
Received in revised form
obliquity are not generally accepted at this time. This study reports on the indications,
20 November 2019
surgical technique and results using pedicle screw instrumentation exclusively with or
Accepted 24 November 2019
without pelvic fixation for spine fusion in patients with NMS.
Available online xxx
Patients and methods: Thirty-seven NMS patients were treated with pedicle screw instrumentation (PSI) between 2007 and 2013 with a minimum follow-up of 24 months. The mean
Keywords:
age at the time of operation was 14.91 ± 2.03 years (range, 11.17e18.58). Posterior spine
Neuromuscular scoliosis
fusion (PSF) was conducted in 33 patients; 4 patients underwent a combined anterior spinal
Scoliosis
release followed by PSF during one-stage surgery. Pelvic fixation was achieved by ilium
Pedicle screw instrumentation
screws combined with S-1 screws in 4 cases and by sacral-alar-iliac (SAI) technique by
Pelvic fixation
Sponseller in 9 cases, respectively. Results: The mean primary Cobb angle was 65.5 (range, 14e103 ) and improved significantly to 19.8 (range, 1e50 , p < 0.001) after surgery and 20.5 (range, 3e57, p ¼ 0.47) at 2 years FU, respectively. Besides, an improvement of pelvic obliquity and T1 tilt angle could be detected. Major complications occurred in 19% and minor complications in 32%. Conclusion: Pedicle screw fixation only for spine fusion in patients with NMS can be applied safely with reasonable complication rates. An excellent correction in all planes, a significant improvement of the pelvic obliquity and almost no loss of correction at 2 years FU were observed. © 2019 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.
*
Study conducted at the Pediatric Orthopaedic Department of Children's Hospital Hamburg-Altona. * Corresponding author. Department of Pediatric Orthopaedic Surgery, Children's Hospital, Hamburg-Altona, University Medical Center Hamburg-Eppendorf Germany, Bleickenallee 38, 22763, Hamburg, Germany. Fax.: þþ49 40 88908 396. € E-mail addresses: [email protected] (N. Stiel), [email protected] (J. Ozden), [email protected] (K. Ridderbusch), [email protected] (M. Moritz), [email protected] (P. Kunkel), [email protected] (A. Gulati), [email protected] (C. Hagemann), [email protected] (K. Mladenov), [email protected] (R. Stuecker), [email protected] (A.S. Spiro). 1 € Norbert Stiel and Jasmin Ozden contributed equally to this work and therefore share first authorship. https://doi.org/10.1016/j.surge.2019.11.007 1479-666X/© 2019 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved. Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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Introduction The term neuromuscular scoliosis (NMS) describes spinal deformities caused by a primary dysfunction of the nervous system or the muscles. Neuromuscular scoliosis includes a large number of pathologies, of which cerebral palsy is the most prevalent. Therefore, the incidence of scoliosis is variable and depending on the underlying disease. In general, the incidence of scoliosis is as higher as the severity of the underlying disease and non-ambulatory patients have a higher risk for developing scoliosis than ambulatory patients. For example in patients with cerebral palsy the risk of developing NMS is increasing with GMFCS (gross motor function classification scale) level varying between <25% (GMFCS I, II, III) and 50% (GMFCS IV, V).1 In other diseases like spinal muscle atrophy or myelomeningocele incidence rates are rising up to 100%.2 During growth in adolescence, the progression of some neuromuscular scoliotic curvatures can increase with an average of 2e4 per month.3 Non-operative interventions are rarely effective in the treatment of NMS. There is no evidence for stopping the progression by physiotherapy or bracing.4 Surgical intervention is the first choice to avoid further progression and to correct the deformity.5e7 The surgical procedure depends on the remaining spinal growth potential. Due to an often existing difference between chronological age and bone age radiological determination of patient age is essential. Growing children can be treated by different systems like rib based implants (VEPTR ¼ vertical expandable prosthetic titanium rib) or vertebral body based implants (growing rods). The negative aspect of these methods is a necessary repetitive invasive extension about every 6e9 months. Since a few years non-invasive expandable implants exist (MAGEC) with promising results. For patients with bone age over 12 years definitive treatments should be chosen. In the past, surgical procedures like Harrington, Luque and Cotrel-Dubousset were standard techniques to treat scoliosis through a posterior approach, however, until recently instrumentation using pedicle screws only has not been widely used.3 In addition, the correction of the associated pelvic obliquity in patients by extending the fixation still remains controversial. Some studies compared pelvic fixation with iliac screws to S2 ilium screws and found the latter technique to be advantageous of.8e10 In this study, we report a special subgroup of patients having pedicle screw instrumentation (PSI) exclusively for the treatment of neuromuscular scoliosis (NMS) to answer questions on safety, efficiency and especially the incidence of complications compared with other treatment methods mentioned so far in the literature.
Material & methods In this retrospective study the medical records of all patients with neuromuscular scoliosis who underwent pedicle screw instrumentation with or without pelvic fixation between 2007 and 2013 at our institution were reviewed. Inclusion criteria were: (1) neuromuscular scoliosis of any etiology (Table 1); (2) scoliosis with a major curve > 40 , and/or annual progression > 5 ; (3) a minimum follow up (FU) of at least 24
months. 37 patients fulfilled these criteria. There were 24 male and 13 female patients with various types of neuromuscular disorders and progressive scoliosis (Table 1), who underwent pedicle screw instrumentation only. The mean age at time of surgery was 14.91 ± 2.03 years (range 11.2e18.6 years). Following decortication, autograft from facet joints or spinous processes was mixed with xenograft (TUTOBONE; TUTOGEN Medical GmbH; 91077 Neunkirchen am Brand, Germany). PSF was successfully accomplished in 33 patients; 4 patients with severe rigid lumbar scoliosis underwent a combined anterior spinal release (multilevel anterior discectomy) followed by PSF at one stage. The lowest level of posterior instrumentation was L5 (n ¼ 21), S1 (n ¼ 3) and pelvis (n ¼ 13), respectively. A pelvic obliquity <20 and parallel endplates of L5 and S1 on the Ferguson view was considered to be an indication for not extending the fusion to S1, while pelvic obliquity and non parallel endplates were usually an indication to fuse to the pelvis. Pelvic fixation was conducted using posterior superior iliac spine (PSIS) fixation in 4 cases and by sacral alar iliac (SAI) technique prescribed by Sponseller et al. in 9 cases.11 In addition, gender, age at surgery, time of surgery, total time in hospital, ICU stays and amount of intraoperative blood loss, complications, radiological and clinical outcome were also evaluated. According to patient's compliance, pulmonary function testing was performed prior to surgery including the 1-s forced expiratory volume (FEV1) as well as vital capacity (VC). All patients received cell-saver blood during surgery. All patient also had spinal chord monitoring during the procedure (Neuro Integrative Monitoring Systems, Medtronic GmbH, Earl-Bakken-Platz 1, 40670 Meerbusch, Germany). Postoperative complications were determined according to the classification of Modi et al.12 They were classified as major complications, if they significantly affected the course of recovery like hemo-/pneumothorax, pleural effusion, pulmonary oedema requiring ICU care, complete spinal cord injury, deep wound infection and death. All other complications like atelectasis, pneumonia, mild pleural effusion, urinary tract infection, ileus, vomiting, gastritis, tingling sensation or
Table 1 e Patients diagnosis. Diagnosis ICP M. Duchenne M. Becker Rett-Syndrome MMC Cri-du-Chat-Syndrome Craniocerebral injury Seckel-Syndrome Andermann-Syndrome HMSN Type III CDG-syndrome Type 1a Prader-Willi-Syndrome Sotos-Syndrome H-ABC-Syndrome leukodystrophy Nemalin-Myopathy Unknown
Number of patients 13 6 1 1 2 1 1 1 2 1 2 1 1 1 1 2
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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3
radiating pain in lower limb, superficial infection and wound dehiscence were classified as minor complications.
(range 1e24 ) at the final 2 year follow up (p ¼ 0.06) without any significance, respectively.
Radiographic analysis
Complications
Preoperative radiographs including standing or sitting posteroanterior (PA), lateral and side-bending views were performed in each case. Bending or traction radiographs were done in order to determine the flexibility of the main curve and to identify the necessary level of instrumentation. At the same time, in order to estimate L5 tilt over S1 endplate the Ferguson view was applied. The posteroanterior projection was used to determine the pelvic obliquity and T1 tilt. Pre- and postoperative radiographs taken immediately after surgery and at last follow-up were analysed. Two physicians independently performed all measurements. Any discrepancy was discussed until a final result was found by consensus. Scoliosis and kyphosis were assessed according to established standards. In addition, T1 tilt angle (angle between a horizontal line and the superior endplate of T1) and pelvic obliquity (measured as a 90 angle between T1 and S1 and a line between the iliac crests) were determined.13 Sagittal imbalance parameters like pelvic tilt, sacral slope or pelvic incidence have not been measured.
Regarding the complications, we found 12 minor complications: In 5 cases we noticed urinary tract infections; 4 patients developed a mild respiratory tract infection/pneumonia; 3 patients developed superficial wound infections, which were treated with antibiotics. Concerning major complications there were 3 early deep wound infections managed with combined regimen of local debridement and 6 weeks of antibiotic therapy without implant removal. In two of these patients microorganisms were detected. First was staphylococcus aureus, second was citrobacter koseri. Regarding implants and fixation-related issues 3 complications occurred. One patient, who had a regular postoperative course after surgery, developed a complete spinal cord injury after trauma, 3 months after primary surgery, with compression fracture of TH3 and consecutive traumatic proximal junctional kyphosis (PJK). Revision surgery was performed but recovery did not occur. In another patient, an implant-correlated infection was seen. This lead to revision of the iliac screws followed by wound debridement and extended antibiotic treatment. In the third patient, a loosening of implants was observed. An ilium anchor was used to stabilize the distal fusion. One additional patient developed acute suppurative pancreatitis (ASP) during the postoperative period in hospital. This may be due to acute correction of extensive spine deformity which may have caused tension to the duodenum resulting in out-flow problems of pancreas fluid. An adequate nutritional support as well as a parenteral nutrition (PN) was given which lead to normalisation of the laboratory parameters without any midterm consequences as assessed by clinical evaluation.
Statistical analysis All of the analyses were performed using IBM SPSS Statistics for Windows, version 20 (IBM Corp., Armonk, N.Y., USA). Values are given as means, standard deviations (SD) and ranges (minimum to maximum). Student paired t test was applied to compare pre- and post-treatment values. A p-value 0.001 was considered statistically significant.
Results The mean operative time was 344 ± 99 (range 182e550) minutes. The mean intraoperative blood loss was 1503 ± 867 (range 400e3420) ml. All patients received intravenously tranexamic acid as well as cell saver substitution during operation.14 The mean hospital stay was 16.09 ± 5.6 (range 9e36) days. Average ICU-stay was 2.3 ± 2.97 (range 1e17) days.
Radiographic findings The mean preoperative major curve measured 65.46 ± 21.46 (range 14e103 ) and improved significantly to 19.83 ± 12.5 (range 1e50 ) immediately after the index procedure (p < 0.001). Similarly, at follow up examination after 24 months, the mean curve measured 20.46 ± 13.07 (range 3e57 , p ¼ 0.47). The mean preoperative T1 tilt angle was 11.41 ± 10.06 (range 2e48 ) and 5.6 ± 3.96 (range 1e19 ) postoperatively (p < 0.001), and remained almost constant with 5.32 ± 3.65 (range 1e18 , p ¼ 0.64) at the 2-year follow-up examination. On the other hand, the mean pelvic obliquity was corrected from 13.11 ± 11.52 (range 0e47 ) preoperatively to 3.92 ± 3.27 (range 0e14 ) postoperatively (p < 0.001) and was 5.32 ± 4.98
Discussion Neuromuscular scoliosis (NMS) are often rapidly progressive, difficult deformities and need early treatment as well as close observation.5,15,16 Moreover, early referral of patients who are candidates for surgery simplifies treatment and may improve their clinical outcome and quality of life. Additionally, for the medical management of the underlying disease process a careful evaluation and an understanding of the primary disease and its prognosis are key elementary steps. Besides this, different underlying conditions, comorbidities and a wide range of treatment modalities make their management challenging. Bracing is often not accepted and less effective in neuromuscular patients.12,17 However, in patients with neuromuscular early onset scoliosis under 10 years of age a non-fusion technique is the method of choice to allow further thorax- and lung growth in order to prevent patients from restrictive lung disease. In addition, magnetically controlled growing rods (MCGR) with different anchoring methods are used to treat neuromuscular scoliosis in such cases. Especially among older patients
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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definitive posterior spinal fusion is considered to be the gold standard for the treatment of NMS. The length of instrumentation, especially concerning the end of lower foundation with or without pelvic fixation, is still discussed in the literature. Although some authors recommend a pelvic fixation in case pelvic obliquity exceeds more than 15 18,19 In our cohort spinal fusion using total pedicle screw instrumentation with or without pelvic fixation for the treatment of progressive neuromuscular scoliosis of different etiologies was effective to correct primary spinal curvature, T1 tilt angle and pelvic obliquity. A primary correction of the deformity from 65.5 to 19.8 (70%) (p < 0.0001) could be reached. Furthermore, pelvic obliquity could be corrected from 13.1 to 3.9 (p < 0.0001). There was no significant loss of correction at 24 months of follow-up regarding all parameters. The segmental pedicle screw construct for correcting spinal deformities demonstrated lesser complication rates as well as higher correction rates compared to the traditionally used Unit-rod instrumentation technique.6 Our results are promising in comparison to other reports dealing with the effectiveness of pedicle screw technique. The results of this study are similar to those of Modi et al., who reported postoperative correction rates of up 63% Cobb's angle and 56% pelvic obliquity, respectively.5 Similarly, the secondary loss of correction ranged from 1.3 to 1.7 for the coronal plane of the scoliosis and from 0 to 2.7 for pelvic obliquity.5,12,18 Regarding secondary loss of correction, we identified an average loss of 0.6 for the coronal plane of the scoliosis and 1.4 for pelvic obliquity, respectively, but this was not significant. In the current study two different types of pelvic fixation techniques were applied. Posterior superior iliac spine (PSIS) fixation was used by inserting iliac screws through the PSIS and by connecting them to the rods in 4 cases. The major disadvantage of this construct is that the iliac screws are rather prominent and a connection device to the long rods is needed to reduce loads on iliac screws.20 The SAI technique avoids these disadvantages and was therefore used as the standard procedure in almost all patients. Furthermore, the secondary loss of correction depending on the lower level of instrumentation was analysed (Table 2). In general, a very good correction of curves could be achieved when fusion was performed to L5 or extended to the pelvis with a minimal loss of correction in both groups after 2 years. In both groups, an improvement of T1 tilt angle and pelvic obliquity with minor changes at last follow-up was noted. Regarding intraoperative blood loss patients with NMS seem to have a higher risk than other scoliosis types.21 Therefore, it is important to be prepared for a significant blood loss in this patient population. In this study an average
Table 3 e Complication rates. Major complications
Number of patients
material breakage, loosening or revision surgery acute pancreatitis with sepsis deep wound infection
3
Minor complications
Number of patients
urinary tract infection respiratory infection superficial wound infection
5 4 3
1 3
blood loss of about 1.5 L was noticed. In comparison to former surgical techniques, this is far less than reported in the other studies.3,5,15 In addition, surgical care in patients with NMS is often more complicated due to relatively poor nutrition and associated cardiopulmonary comorbidities. Complication rates between 22% and 44% following surgical treatment of neuromuscular scoliosis have been reported.5,12,22 Implantassociated complications are of particular interest. In the present study, a major complication rate of 19% including 3 implant-related complications was found (Table 3). In one case, a spinal cord injury due to TH3 fracture and junctional kyphosis after trauma occurred. However, this was not related to the surgical procedure but presents a risk factor for some patients with neuromuscular scoliosis and poor head control. Furthermore, additional surgical revision including implant removal was needed in one patient due to infection and in another case due to instability. These patients had instrumentation to L5. Interestingly, in the group with fixation to the pelvis no implant-associated complications were seen. Jain et al. described 5 (13%) implant-related complications in a similar cohort using the Sponseller technique. 4 of these patients had a deep wound infection and in one case a unilateral screw break was found.23 In our practice the S2-ilium technique by Sponseller has become the standard of pelvic fixation because of its strength of fixation and very low incidence of complications. Abdominal complications after surgery such as pancreatitis and superior mesenteric artery syndrome are challenging issues in patients with neuromuscular scoliosis.24,25 In this study there was only one case of pancreatitis after spinal fusion. Consequently, to minimize the risk of this serious complication, we implemented a pre-, peri- and postoperative management comparable to the findings of Sitoula et al.24 This included laboratory tests (serum amylase and lipase), physical and ultrasound examination for pancreatitis screening. Since introduction of this protocol no further cases of pancreatitis were recorded. We also recommend an
Table 2 e Correction loss after FU (degree ) regarding the fusion level. Fusion level
Number of patients
Cobb angle ( )
T1 tilt angle ( )
pelvic obliquity ( )
Kyphosis ( )
Lordosis ( )
Up to L5 Up to S1 Up to S2/ilium
21 3 13
0,7 3,33 0,92
0,29 2 0,77
0,9 3,33 1,77
1,48 3 4
1,43 3,67 0,38
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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interdisciplinary preoperative evaluation of all patients by different disciplines (cardiology, anaesthesia, paediatrics and radiology) to detect any significant risks and comorbidities and to minimize complications. The limitations of this study are (1) its retrospective design, (2) the relatively small number of patients, (3) the lack of randomization and (4) a relatively short follow-up period to comment on the adequacy of instrumentation and fusion, considering the average life expectancy, but the midterm results after 2-years of follow-up are encouraging.
6.
7.
8. 9.
Conclusion In conclusion, pedicle screw instrumentation only in management of neuromuscular scoliosis (NMS) is a safe technique which permits good correction of the primary curve, T1-tilt angle as well as pelvic obliquity without secondary correction loss of these parameters at 2-years of follow-up. Our study demonstrated that in case of pelvic fixation, the S2 ilium technique by Sponseller is a safe and effective method in the pediatric population for the treatment of NMS with significant pelvic obliquity. Moreover, pelvic instrumentation is recommended (1) if there is no parallel orientation of the L5 and S1 endplates on the Ferguson view, (2) if pelvic obliquity exceeds 20 , (3) in patients with cerebral palsy (CP) due to asymmetric tonus and (4) in non-ambulatory patients. However, further multicentre trials should be conducted to evaluate the transferability of the applied criteria to all patients with neuromuscular scoliosis.
10.
11.
12.
13.
14.
15.
Financial support This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
16.
17.
Declaration of Competing Interest None.
references
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with cerebral palsy: A three-year follow-up study. Spine (Phila Pa 1976) 2009;34(11):1167e75. Tsirikos AI, Mains E. Surgical correction of spinal deformity in patients with cerebral palsy using pedicle screw instrumentation. J Spinal Disord Tech 2012;25(7):401e8. Mattila M, Jalanko T, Puisto V, Pajulo O, Helenius IJ. Hybrid versus total pedicle screw instrumentation in patients undergoing surgery for neuromuscular scoliosis: A comparative study with matched cohorts. J Bone Jt Surg - Ser B. 2012;94 B(10):1393e8. Myung KS, Lee C, Skaggs DL. Early pelvic fixation failure in neuromuscular scoliosis. J Pediatr Orthop 2015;35(3):258e65. Lee MC, Jarvis C, Solomito MJ, Thomson JD. Comparison of S2Alar and traditional iliac screw pelvic fixation for pediatric neuromuscular deformity. Spine J 2018;18(4):648e54. Shabtai L, Andras LM, Portman M, Harris LR, Choi PD, Tolo VT, et al. Sacral Alar Iliac (SAI) screws fail 75% less frequently than Iliac screws in neuromuscular scoliosis. J Pediatr Orthop 2017;37(8):e470e5. Sponseller PD, Zimmerman RM, Ko PS, Pull Ter Gunne AF, Mohamed AS, Chang TL, et al. Low profile pelvic fixation with the sacral alar iliac technique in the pediatric population improves results at two-year minimum follow-up. Spine (Phila Pa 1976) 2010;35(20):1887e92. Modi HN, Suh SW, Yang JH, Cho JW, Hong JY, Singh SU, et al. Surgical complications in neuromuscular scoliosis operated with posterior- only approach using pedicle screw fixation. Scoliosis 2009;4. Dayer R, Ouellet JA, Saran N. Pelvic fixation for neuromuscular scoliosis deformity correction. Curr Rev Musculoskelet Med 2012;5(2):91e101. Goobie SM, Faraoni D. Tranexamic acid and perioperative bleeding in children: what do we still need to know? Curr Opin Anaesthesiol 2019;32(3):343e52. Colombo LF, Motta F. Revision of surgical correction of scoliosis in pediatric patients affected by neuromuscular pathology using Unit Rod instrumentation. Eur Spine J 2013;22(SUPPL.6). Thacker M, Hui JHP, Wong HK, Chatterjee A, Lee EH. Spinal fusion and instrumentation for paediatric neuromuscular scoliosis: retrospective review. J Orthop Surg 2002;10:144e51. Sponseller PD, Yang JS, Thompson GH, McCarthy RE, Emans JB, Skaggs DL, et al. Pelvic fixation of growing rods: comparison of constructs. Spine (Phila Pa 1976) 2009;34(16):1706e10. Modi HN, Suh SW, Song HR, Yang JH, Jajodia N. Evaluation of pelvic fixation in neuromuscular scoliosis: a retrospective study in 55 patients. Int Orthop 2010;34(1):89e96. McCall RE, Hayes B. Long-term outcome in neuromuscular scoliosis fused only to lumbar 5. Spine (Phila Pa 1976) 2005;30(18):2056e60. Desrochers-Perrault F, Aubin CE, Wang X, Schwend RM. Biomechanical analysis of iliac screw fixation in spinal deformity instrumentation. Clin Biomech 2014;29(6):614e21. Jain A, Njoku DB, Sponseller PD. Does patient diagnosis predict blood loss during posterior spinal fusion in children? Spine (Phila Pa 1976) 2012;37(19):1683e7. Modi HN, Suh SW, Hong JY, Cho JW, Park JH, Yang JH. Treatment and complications in flaccid neuromuscular scoliosis (Duchenne muscular dystrophy and spinal muscular atrophy) with posterior-only pedicle screw instrumentation. Eur Spine J 2010;19(3):384e93. Jain A, Sullivan BT, Kuwabara A, Kebaish KM, Sponseller PD. Sacral-Alar-Iliac fixation in children with neuromuscular scoliosis: minimum 5-year follow-up. World Neurosurg 2017;108:474e8.
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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24. Sitoula P, Holmes L, Sees J, Rogers K, Dabney K, Miller F. The long-term outcome of early spine fusion for scoliosis in children with cerebral palsy. Clin Spine Surg 2016;29:E406e12.
25. Nishnianidze T, Bayhan IA, Abousamra O, Sees J, Rogers KJ, Dabney KW, et al. Factors predicting postoperative complications following spinal fusions in children with cerebral palsy scoliosis. Eur Spine J 2016;25(2):627e34.
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up* a,1 € Norbert Stiel a,1, Jasmin Ozden , Karsten Ridderbusch a, Menard Moritz a, Philip Kunkel b, Amit Gulati c, Christian Hagemann b, Kiril Mladenov a, Ralf Stuecker a, Alexander S. Spiro a,* a
Department of Pediatric Orthopaedic Surgery, Children's Hospital Hamburg-Altona, University Medical Center Hamburg-Eppendorf, Hamburg, Germany b Department of Pediatric Neurosurgery, Children's Hospital Hamburg-Altona, University Medical Center HamburgEppendorf, Hamburg, Germany c Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
article info
abstract
Article history:
Objective: Neuromuscular scoliosis (NMS) is often associated with rapid progressive spinal
Received 26 August 2019
deformities. Indications, when to extend the instrumentation to the pelvis for pelvic
Received in revised form
obliquity are not generally accepted at this time. This study reports on the indications,
20 November 2019
surgical technique and results using pedicle screw instrumentation exclusively with or
Accepted 24 November 2019
without pelvic fixation for spine fusion in patients with NMS.
Available online xxx
Patients and methods: Thirty-seven NMS patients were treated with pedicle screw instrumentation (PSI) between 2007 and 2013 with a minimum follow-up of 24 months. The mean
Keywords:
age at the time of operation was 14.91 ± 2.03 years (range, 11.17e18.58). Posterior spine
Neuromuscular scoliosis
fusion (PSF) was conducted in 33 patients; 4 patients underwent a combined anterior spinal
Scoliosis
release followed by PSF during one-stage surgery. Pelvic fixation was achieved by ilium
Pedicle screw instrumentation
screws combined with S-1 screws in 4 cases and by sacral-alar-iliac (SAI) technique by
Pelvic fixation
Sponseller in 9 cases, respectively. Results: The mean primary Cobb angle was 65.5 (range, 14e103 ) and improved significantly to 19.8 (range, 1e50 , p < 0.001) after surgery and 20.5 (range, 3e57, p ¼ 0.47) at 2 years FU, respectively. Besides, an improvement of pelvic obliquity and T1 tilt angle could be detected. Major complications occurred in 19% and minor complications in 32%. Conclusion: Pedicle screw fixation only for spine fusion in patients with NMS can be applied safely with reasonable complication rates. An excellent correction in all planes, a significant improvement of the pelvic obliquity and almost no loss of correction at 2 years FU were observed. © 2019 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.
*
Study conducted at the Pediatric Orthopaedic Department of Children's Hospital Hamburg-Altona. * Corresponding author. Department of Pediatric Orthopaedic Surgery, Children's Hospital, Hamburg-Altona, University Medical Center Hamburg-Eppendorf Germany, Bleickenallee 38, 22763, Hamburg, Germany. Fax.: þþ49 40 88908 396. € E-mail addresses: [email protected] (N. Stiel), [email protected] (J. Ozden), [email protected] (K. Ridderbusch), [email protected] (M. Moritz), [email protected] (P. Kunkel), [email protected] (A. Gulati), [email protected] (C. Hagemann), [email protected] (K. Mladenov), [email protected] (R. Stuecker), [email protected] (A.S. Spiro). 1 € Norbert Stiel and Jasmin Ozden contributed equally to this work and therefore share first authorship. https://doi.org/10.1016/j.surge.2019.11.007 1479-666X/© 2019 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved. Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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Introduction The term neuromuscular scoliosis (NMS) describes spinal deformities caused by a primary dysfunction of the nervous system or the muscles. Neuromuscular scoliosis includes a large number of pathologies, of which cerebral palsy is the most prevalent. Therefore, the incidence of scoliosis is variable and depending on the underlying disease. In general, the incidence of scoliosis is as higher as the severity of the underlying disease and non-ambulatory patients have a higher risk for developing scoliosis than ambulatory patients. For example in patients with cerebral palsy the risk of developing NMS is increasing with GMFCS (gross motor function classification scale) level varying between <25% (GMFCS I, II, III) and 50% (GMFCS IV, V).1 In other diseases like spinal muscle atrophy or myelomeningocele incidence rates are rising up to 100%.2 During growth in adolescence, the progression of some neuromuscular scoliotic curvatures can increase with an average of 2e4 per month.3 Non-operative interventions are rarely effective in the treatment of NMS. There is no evidence for stopping the progression by physiotherapy or bracing.4 Surgical intervention is the first choice to avoid further progression and to correct the deformity.5e7 The surgical procedure depends on the remaining spinal growth potential. Due to an often existing difference between chronological age and bone age radiological determination of patient age is essential. Growing children can be treated by different systems like rib based implants (VEPTR ¼ vertical expandable prosthetic titanium rib) or vertebral body based implants (growing rods). The negative aspect of these methods is a necessary repetitive invasive extension about every 6e9 months. Since a few years non-invasive expandable implants exist (MAGEC) with promising results. For patients with bone age over 12 years definitive treatments should be chosen. In the past, surgical procedures like Harrington, Luque and Cotrel-Dubousset were standard techniques to treat scoliosis through a posterior approach, however, until recently instrumentation using pedicle screws only has not been widely used.3 In addition, the correction of the associated pelvic obliquity in patients by extending the fixation still remains controversial. Some studies compared pelvic fixation with iliac screws to S2 ilium screws and found the latter technique to be advantageous of.8e10 In this study, we report a special subgroup of patients having pedicle screw instrumentation (PSI) exclusively for the treatment of neuromuscular scoliosis (NMS) to answer questions on safety, efficiency and especially the incidence of complications compared with other treatment methods mentioned so far in the literature.
Material & methods In this retrospective study the medical records of all patients with neuromuscular scoliosis who underwent pedicle screw instrumentation with or without pelvic fixation between 2007 and 2013 at our institution were reviewed. Inclusion criteria were: (1) neuromuscular scoliosis of any etiology (Table 1); (2) scoliosis with a major curve > 40 , and/or annual progression > 5 ; (3) a minimum follow up (FU) of at least 24
months. 37 patients fulfilled these criteria. There were 24 male and 13 female patients with various types of neuromuscular disorders and progressive scoliosis (Table 1), who underwent pedicle screw instrumentation only. The mean age at time of surgery was 14.91 ± 2.03 years (range 11.2e18.6 years). Following decortication, autograft from facet joints or spinous processes was mixed with xenograft (TUTOBONE; TUTOGEN Medical GmbH; 91077 Neunkirchen am Brand, Germany). PSF was successfully accomplished in 33 patients; 4 patients with severe rigid lumbar scoliosis underwent a combined anterior spinal release (multilevel anterior discectomy) followed by PSF at one stage. The lowest level of posterior instrumentation was L5 (n ¼ 21), S1 (n ¼ 3) and pelvis (n ¼ 13), respectively. A pelvic obliquity <20 and parallel endplates of L5 and S1 on the Ferguson view was considered to be an indication for not extending the fusion to S1, while pelvic obliquity and non parallel endplates were usually an indication to fuse to the pelvis. Pelvic fixation was conducted using posterior superior iliac spine (PSIS) fixation in 4 cases and by sacral alar iliac (SAI) technique prescribed by Sponseller et al. in 9 cases.11 In addition, gender, age at surgery, time of surgery, total time in hospital, ICU stays and amount of intraoperative blood loss, complications, radiological and clinical outcome were also evaluated. According to patient's compliance, pulmonary function testing was performed prior to surgery including the 1-s forced expiratory volume (FEV1) as well as vital capacity (VC). All patients received cell-saver blood during surgery. All patient also had spinal chord monitoring during the procedure (Neuro Integrative Monitoring Systems, Medtronic GmbH, Earl-Bakken-Platz 1, 40670 Meerbusch, Germany). Postoperative complications were determined according to the classification of Modi et al.12 They were classified as major complications, if they significantly affected the course of recovery like hemo-/pneumothorax, pleural effusion, pulmonary oedema requiring ICU care, complete spinal cord injury, deep wound infection and death. All other complications like atelectasis, pneumonia, mild pleural effusion, urinary tract infection, ileus, vomiting, gastritis, tingling sensation or
Table 1 e Patients diagnosis. Diagnosis ICP M. Duchenne M. Becker Rett-Syndrome MMC Cri-du-Chat-Syndrome Craniocerebral injury Seckel-Syndrome Andermann-Syndrome HMSN Type III CDG-syndrome Type 1a Prader-Willi-Syndrome Sotos-Syndrome H-ABC-Syndrome leukodystrophy Nemalin-Myopathy Unknown
Number of patients 13 6 1 1 2 1 1 1 2 1 2 1 1 1 1 2
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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radiating pain in lower limb, superficial infection and wound dehiscence were classified as minor complications.
(range 1e24 ) at the final 2 year follow up (p ¼ 0.06) without any significance, respectively.
Radiographic analysis
Complications
Preoperative radiographs including standing or sitting posteroanterior (PA), lateral and side-bending views were performed in each case. Bending or traction radiographs were done in order to determine the flexibility of the main curve and to identify the necessary level of instrumentation. At the same time, in order to estimate L5 tilt over S1 endplate the Ferguson view was applied. The posteroanterior projection was used to determine the pelvic obliquity and T1 tilt. Pre- and postoperative radiographs taken immediately after surgery and at last follow-up were analysed. Two physicians independently performed all measurements. Any discrepancy was discussed until a final result was found by consensus. Scoliosis and kyphosis were assessed according to established standards. In addition, T1 tilt angle (angle between a horizontal line and the superior endplate of T1) and pelvic obliquity (measured as a 90 angle between T1 and S1 and a line between the iliac crests) were determined.13 Sagittal imbalance parameters like pelvic tilt, sacral slope or pelvic incidence have not been measured.
Regarding the complications, we found 12 minor complications: In 5 cases we noticed urinary tract infections; 4 patients developed a mild respiratory tract infection/pneumonia; 3 patients developed superficial wound infections, which were treated with antibiotics. Concerning major complications there were 3 early deep wound infections managed with combined regimen of local debridement and 6 weeks of antibiotic therapy without implant removal. In two of these patients microorganisms were detected. First was staphylococcus aureus, second was citrobacter koseri. Regarding implants and fixation-related issues 3 complications occurred. One patient, who had a regular postoperative course after surgery, developed a complete spinal cord injury after trauma, 3 months after primary surgery, with compression fracture of TH3 and consecutive traumatic proximal junctional kyphosis (PJK). Revision surgery was performed but recovery did not occur. In another patient, an implant-correlated infection was seen. This lead to revision of the iliac screws followed by wound debridement and extended antibiotic treatment. In the third patient, a loosening of implants was observed. An ilium anchor was used to stabilize the distal fusion. One additional patient developed acute suppurative pancreatitis (ASP) during the postoperative period in hospital. This may be due to acute correction of extensive spine deformity which may have caused tension to the duodenum resulting in out-flow problems of pancreas fluid. An adequate nutritional support as well as a parenteral nutrition (PN) was given which lead to normalisation of the laboratory parameters without any midterm consequences as assessed by clinical evaluation.
Statistical analysis All of the analyses were performed using IBM SPSS Statistics for Windows, version 20 (IBM Corp., Armonk, N.Y., USA). Values are given as means, standard deviations (SD) and ranges (minimum to maximum). Student paired t test was applied to compare pre- and post-treatment values. A p-value 0.001 was considered statistically significant.
Results The mean operative time was 344 ± 99 (range 182e550) minutes. The mean intraoperative blood loss was 1503 ± 867 (range 400e3420) ml. All patients received intravenously tranexamic acid as well as cell saver substitution during operation.14 The mean hospital stay was 16.09 ± 5.6 (range 9e36) days. Average ICU-stay was 2.3 ± 2.97 (range 1e17) days.
Radiographic findings The mean preoperative major curve measured 65.46 ± 21.46 (range 14e103 ) and improved significantly to 19.83 ± 12.5 (range 1e50 ) immediately after the index procedure (p < 0.001). Similarly, at follow up examination after 24 months, the mean curve measured 20.46 ± 13.07 (range 3e57 , p ¼ 0.47). The mean preoperative T1 tilt angle was 11.41 ± 10.06 (range 2e48 ) and 5.6 ± 3.96 (range 1e19 ) postoperatively (p < 0.001), and remained almost constant with 5.32 ± 3.65 (range 1e18 , p ¼ 0.64) at the 2-year follow-up examination. On the other hand, the mean pelvic obliquity was corrected from 13.11 ± 11.52 (range 0e47 ) preoperatively to 3.92 ± 3.27 (range 0e14 ) postoperatively (p < 0.001) and was 5.32 ± 4.98
Discussion Neuromuscular scoliosis (NMS) are often rapidly progressive, difficult deformities and need early treatment as well as close observation.5,15,16 Moreover, early referral of patients who are candidates for surgery simplifies treatment and may improve their clinical outcome and quality of life. Additionally, for the medical management of the underlying disease process a careful evaluation and an understanding of the primary disease and its prognosis are key elementary steps. Besides this, different underlying conditions, comorbidities and a wide range of treatment modalities make their management challenging. Bracing is often not accepted and less effective in neuromuscular patients.12,17 However, in patients with neuromuscular early onset scoliosis under 10 years of age a non-fusion technique is the method of choice to allow further thorax- and lung growth in order to prevent patients from restrictive lung disease. In addition, magnetically controlled growing rods (MCGR) with different anchoring methods are used to treat neuromuscular scoliosis in such cases. Especially among older patients
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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definitive posterior spinal fusion is considered to be the gold standard for the treatment of NMS. The length of instrumentation, especially concerning the end of lower foundation with or without pelvic fixation, is still discussed in the literature. Although some authors recommend a pelvic fixation in case pelvic obliquity exceeds more than 15 18,19 In our cohort spinal fusion using total pedicle screw instrumentation with or without pelvic fixation for the treatment of progressive neuromuscular scoliosis of different etiologies was effective to correct primary spinal curvature, T1 tilt angle and pelvic obliquity. A primary correction of the deformity from 65.5 to 19.8 (70%) (p < 0.0001) could be reached. Furthermore, pelvic obliquity could be corrected from 13.1 to 3.9 (p < 0.0001). There was no significant loss of correction at 24 months of follow-up regarding all parameters. The segmental pedicle screw construct for correcting spinal deformities demonstrated lesser complication rates as well as higher correction rates compared to the traditionally used Unit-rod instrumentation technique.6 Our results are promising in comparison to other reports dealing with the effectiveness of pedicle screw technique. The results of this study are similar to those of Modi et al., who reported postoperative correction rates of up 63% Cobb's angle and 56% pelvic obliquity, respectively.5 Similarly, the secondary loss of correction ranged from 1.3 to 1.7 for the coronal plane of the scoliosis and from 0 to 2.7 for pelvic obliquity.5,12,18 Regarding secondary loss of correction, we identified an average loss of 0.6 for the coronal plane of the scoliosis and 1.4 for pelvic obliquity, respectively, but this was not significant. In the current study two different types of pelvic fixation techniques were applied. Posterior superior iliac spine (PSIS) fixation was used by inserting iliac screws through the PSIS and by connecting them to the rods in 4 cases. The major disadvantage of this construct is that the iliac screws are rather prominent and a connection device to the long rods is needed to reduce loads on iliac screws.20 The SAI technique avoids these disadvantages and was therefore used as the standard procedure in almost all patients. Furthermore, the secondary loss of correction depending on the lower level of instrumentation was analysed (Table 2). In general, a very good correction of curves could be achieved when fusion was performed to L5 or extended to the pelvis with a minimal loss of correction in both groups after 2 years. In both groups, an improvement of T1 tilt angle and pelvic obliquity with minor changes at last follow-up was noted. Regarding intraoperative blood loss patients with NMS seem to have a higher risk than other scoliosis types.21 Therefore, it is important to be prepared for a significant blood loss in this patient population. In this study an average
Table 3 e Complication rates. Major complications
Number of patients
material breakage, loosening or revision surgery acute pancreatitis with sepsis deep wound infection
3
Minor complications
Number of patients
urinary tract infection respiratory infection superficial wound infection
5 4 3
1 3
blood loss of about 1.5 L was noticed. In comparison to former surgical techniques, this is far less than reported in the other studies.3,5,15 In addition, surgical care in patients with NMS is often more complicated due to relatively poor nutrition and associated cardiopulmonary comorbidities. Complication rates between 22% and 44% following surgical treatment of neuromuscular scoliosis have been reported.5,12,22 Implantassociated complications are of particular interest. In the present study, a major complication rate of 19% including 3 implant-related complications was found (Table 3). In one case, a spinal cord injury due to TH3 fracture and junctional kyphosis after trauma occurred. However, this was not related to the surgical procedure but presents a risk factor for some patients with neuromuscular scoliosis and poor head control. Furthermore, additional surgical revision including implant removal was needed in one patient due to infection and in another case due to instability. These patients had instrumentation to L5. Interestingly, in the group with fixation to the pelvis no implant-associated complications were seen. Jain et al. described 5 (13%) implant-related complications in a similar cohort using the Sponseller technique. 4 of these patients had a deep wound infection and in one case a unilateral screw break was found.23 In our practice the S2-ilium technique by Sponseller has become the standard of pelvic fixation because of its strength of fixation and very low incidence of complications. Abdominal complications after surgery such as pancreatitis and superior mesenteric artery syndrome are challenging issues in patients with neuromuscular scoliosis.24,25 In this study there was only one case of pancreatitis after spinal fusion. Consequently, to minimize the risk of this serious complication, we implemented a pre-, peri- and postoperative management comparable to the findings of Sitoula et al.24 This included laboratory tests (serum amylase and lipase), physical and ultrasound examination for pancreatitis screening. Since introduction of this protocol no further cases of pancreatitis were recorded. We also recommend an
Table 2 e Correction loss after FU (degree ) regarding the fusion level. Fusion level
Number of patients
Cobb angle ( )
T1 tilt angle ( )
pelvic obliquity ( )
Kyphosis ( )
Lordosis ( )
Up to L5 Up to S1 Up to S2/ilium
21 3 13
0,7 3,33 0,92
0,29 2 0,77
0,9 3,33 1,77
1,48 3 4
1,43 3,67 0,38
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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interdisciplinary preoperative evaluation of all patients by different disciplines (cardiology, anaesthesia, paediatrics and radiology) to detect any significant risks and comorbidities and to minimize complications. The limitations of this study are (1) its retrospective design, (2) the relatively small number of patients, (3) the lack of randomization and (4) a relatively short follow-up period to comment on the adequacy of instrumentation and fusion, considering the average life expectancy, but the midterm results after 2-years of follow-up are encouraging.
6.
7.
8. 9.
Conclusion In conclusion, pedicle screw instrumentation only in management of neuromuscular scoliosis (NMS) is a safe technique which permits good correction of the primary curve, T1-tilt angle as well as pelvic obliquity without secondary correction loss of these parameters at 2-years of follow-up. Our study demonstrated that in case of pelvic fixation, the S2 ilium technique by Sponseller is a safe and effective method in the pediatric population for the treatment of NMS with significant pelvic obliquity. Moreover, pelvic instrumentation is recommended (1) if there is no parallel orientation of the L5 and S1 endplates on the Ferguson view, (2) if pelvic obliquity exceeds 20 , (3) in patients with cerebral palsy (CP) due to asymmetric tonus and (4) in non-ambulatory patients. However, further multicentre trials should be conducted to evaluate the transferability of the applied criteria to all patients with neuromuscular scoliosis.
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15.
Financial support This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
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Declaration of Competing Interest None.
references
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Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007
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24. Sitoula P, Holmes L, Sees J, Rogers K, Dabney K, Miller F. The long-term outcome of early spine fusion for scoliosis in children with cerebral palsy. Clin Spine Surg 2016;29:E406e12.
25. Nishnianidze T, Bayhan IA, Abousamra O, Sees J, Rogers KJ, Dabney KW, et al. Factors predicting postoperative complications following spinal fusions in children with cerebral palsy scoliosis. Eur Spine J 2016;25(2):627e34.
Please cite this article as: Stiel N et al., Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up, The Surgeon, https://doi.org/10.1016/ j.surge.2019.11.007