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Scientific Articles   |    
Complications of Growing-Rod Treatment for Early-Onset ScoliosisAnalysis of One Hundred and Forty Patients
Shay Bess, MD1; Behrooz A. Akbarnia, MD2; George H. Thompson, MD3; Paul D. Sponseller, MD4; Suken A. Shah, MD5; Hazem El Sebaie, FRCS, MD6; Oheneba Boachie-Adjei, MD7; Lawrence I. Karlin, MD8; Sarah Canale, BS2; Connie Poe-Kochert, RN, CNP3; David L. Skaggs, MD9
1 Rocky Mountain Hospital for Children, 1721 East 19th Avenue, Suite 244, Denver, CO 80218
2 San Diego Center for Spinal Disorders, 4130 La Jolla Village Drive, #300, La Jolla, CA 92037. E-mail address for B.A. Akbarnia: akbarnia@ucsd.edu
3 Department of Pediatric Orthopaedics, Rainbow Babies & Children's Hospital, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106
4 Department of Orthopedic Surgery, Johns Hopkins Hospital, 601 North Caroline Street, #5212, Baltimore, MD 21287-0882
5 Nemours Children's Clinic, 1600 Rockland Road, Wilmington, DE 19803
6 Cairo University, 22 Degla Street, Mohandessine, Giza, Post No. 12411, Egypt
7 Hospital for Special Surgery, 523 East 72nd Street, 2nd Floor, New York, NY 10021
8 Department of Orthopaedic Surgery, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02115
9 Division of Orthopaedic Surgery, Childrens Hospital Los Angeles, 4650 Sunset Boulevard, M/S 69, Los Angeles, CA 90027
View Disclosures and Other Information
Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in excess of $10,000 from the Growing Spine Foundation. In addition, one or more of the authors or a member of his or her immediate family received, in any one year, payments or other benefits in excess of $10,000 or a commitment or agreement to provide such benefits from commercial entities (DePuy Spine, Ellipse Technologies, Phygen, Nuvasive, K2M, Medtronic, Axial Biotech, Stryker, Zimmer, and Globus Medical).

A commentary by Lori A. Karol, MD, is available at www.jbjs.org/commentary and is linked to the online version of this article.
Investigation performed at San Diego Center for Spinal Disorders, La Jolla, California

Copyright © 2010 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2010 Nov 03;92(15):2533-2543. doi: 10.2106/JBJS.I.01471
A commentary by Lori A. Karol, MD, is available here
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case

Abstract

Background: 

Previous reports have indicated high complication rates associated with non-fusion surgery in patients with early-onset scoliosis. This study was performed to evaluate the clinical and radiographic complications associated with growing-rod treatment.

Methods: 

Data from the multicenter Growing Spine Study Group database were evaluated. Inclusion criteria were growing-rod treatment for early-onset scoliosis and a minimum of two years of follow-up. Patients were divided into treatment groups according to rod type (single or dual) and rod location (subcutaneous or submuscular). Complications were categorized as wound, implant, alignment, and general (surgical or medical). Surgical procedures were classified as planned and unplanned.

Results: 

Between 1987 and 2005, 140 patients met the inclusion criteria and underwent a total of 897 growing-rod procedures. The mean age at the initial surgery was six years, and the mean duration of follow-up was five years. Eighty-one (58%) of the 140 patients had a minimum of one complication. Nineteen (27%) of the seventy-one patients with a single rod had unplanned procedures because of implant complications, compared with seven (10%) of the sixty-nine patients with dual rods (p = 0.05). Thirteen (26%) of the fifty-one patients with subcutaneous rod placement had wound complications compared with nine of the eighty-eight patients (10%) with submuscular rod placement (p = 0.05). The patients with subcutaneous dual rods had more wound complications, more prominent implants, and more unplanned surgical procedures than did those with submuscular dual rods (p = 0.05). The risk of complications occurring during the treatment period decreased by 13% for each year of increased patient age at the initiation of treatment. The complication risk increased by 24% for each additional surgical procedure performed.

Conclusions: 

Regardless of treatment modality, the management of early-onset scoliosis is prolonged; therefore, complications are frequent and should be expected. Complications can be reduced by delaying initial implantation of the growing rods if possible, using dual rods, and limiting the number of lengthening procedures. Submuscular placement reduces wound and implant-prominence complications and reduces the number of unplanned operations.

Level of Evidence: 

Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

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    References

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    Behrooz A. Akbarnia, MD
    Posted on March 19, 2011
    Dr. Akbarnia and colleagues respond to Mr. Dickson
    Orthopedic Spine Surgeon, San Diego Center for Spinal Disorders, San Diego, California

    The authors appreciate Mr. Dickson’s extensive experience in treating early onset scoliosis (EOS) and thank Mr. Dickson for the insightful comments. We agree that the etiology of EOS in our reported patient population was heterogeneous, and likely reflects the diverse practices of the contributing surgeons. This is one potential benefit of our multi-center study, as a broad range of patients were able to be evaluated, permitting analysis of a population that might not have been otherwise captured in a single institution. Accordingly, the authors were able to evaluate the applicability of growing rod procedures to a variety of conditions associated with EOS, and reported that EOS etiology did not significantly impact complication rates.

    As Mr. Dickson has indicated, because of the potential negative impact of EOS upon pulmonary development, early diagnosis is critical. We also agree that surgical treatment should be delayed as long as possible, as we demonstrated that the risk for complications increased by 13% for each year of increased patient age at the initiation of treatment and the complication risk increased by 24% for each additional surgical procedure performed. However, Mr. Dickson indicates that “the problem with posterior surgery alone is that the front of the spine still carries on growing” and that “anterior growth ablation is fundamental.” The risk of continued anterior vertebral growth and associated crank-shaft phenomenon is a potential problem following spinal arthrodesis among young patients, however treating physicians and parents of patients being treated for EOS must be fully cognizant that growing rod treatment is a temporizing measure aimed at preserving axial skeleton growth thereby allowing thoracic and pulmonary development while simultaneously attempting to control curve progression, and should not be misinterpreted as a definitive treatment modality. Therefore as treating physicians, we repeatedly need to communicate to parents that management of EOS requires prolonged treatment. Although early data exists on patients that have “graduated” from growing rod to definitive treatment, more data is needed to further identify effective treatment strategies for EOS patients that have matured and reached the end of their growth sparing treatment period (1).

    Again, the authors thank Mr. Dickson for his insight and appreciate his generosity in sharing his experience in treating EOS as we hope to further the science for treating this challenging condition.

    Reference

    1. Flynn, J. M.; Tomlinson, L. A.; Pawelek, J.; Thompson, G. H.; McCarthy, R. E.; Akbarnia, B. A.; and Group, G. S. S.: Growing Rod Graduates: Lessons From 58 Patients Who Have Completed Their Lengthenings. In Scoliosis Research Society: 45th Annual Meeting and Combined Course. Edited, Kyoto, Japan, 2010.

    Robert Andrew Dickson, MA, ChM, FRCS, DSc
    Posted on March 19, 2011
    Bess S, Akbarnia BA, Thompson GH et al. Complications of Growing-Rod Treatment for Early-Onset...
    Professor, Past British Volume Chairman, Leeds, United Kingdom

    To the Editor:

    Having considerable experience of early onset scoliosis and its treatment, I was interested to read the article entitled, "Complications of Growing-Rod Treatment for Early-Onset Scoliosis: Analysis of One Hundred and Forty Patient" by Bess et al. in the Journal of Bone and Joint Surgery (Am) (2010;92:2533-43). This distinguished group quite rightly point out that early onset scoliosis can be a dangerous condition particularly for idiopathic thoracic curves which can be very progressive. I note that there are a number of different underlying diagnoses, 52 being neuromuscular, 40 idiopathic and 24 congenital. These are unusual demographics, in contrast to the UK where we have a much higher prevalence rate of early onset idiopathic scoliosis (E.O.I.S.) In Mehta’s group in London (1) and the Leeds Group (2) virtually all were of the idiopathic variety. The worst cases of E.O.I.S. in terms of progression have a particularly early onset, within a matter of a few months from birth, and with a very serious progression potential.

    Although the pulmonary alveolar tree can reduplicate until the age of 7 much of development occurs early on. It is interference with development in the first year or two of life that is the real danger. Davies and Reid likened the post-mortem lung appearances to those encountered in congenital diaphragmatic hernias where from before birth abdominal contents have squashed the developing lung (3). Hence treatment for early onset idiopathic scoliosis is vital from the moment of diagnosis although that in itself can be the source of disappointing delay (4). An Elongation Derotation Flexion (EDF) cast (5) must be applied and the Leeds Group has treated as many if not more than Mehta’s Group in London with comparable success rates.

    For those that do not respond to cast treatment, the blatantly progressive ones, then surgical treatment is the only option. Delay in presentation may explain the average age of surgical treatment in this series was all of 6 years of age, somewhat beyond the cut off point between E.O.I.S. and scoliosis of late onset (6,7). I also note that while the average curve size was 75 degrees at surgery there was a maximum of 147 which is unfortunately too late to be really operable. Of course it is very difficult not to offer some form of treatment to the family of these terrible cases.

    Unfortunately at least 10% of those cases treated conservatively will not respond (1,2) and so the Leeds Group have an experience of more than 50 cases of very early onset idiopathic scoliosis that have required operative intervention. When Harrington introduced his subcutaneous rod technique (8) this really was the first time that curves could be managed operatively throughout growth but it is critical that this programme should be started as early as possible. Pulmonary function tests in this study would have been of interest.

    The problem with posterior surgery alone is that the front of the spine still carries on growing which is indeed the ultimate problem in structural scoliosis (9). For the particularly early progressive cases it is very important to go anteriorly in a first stage to eliminate anterior spinal growth before a second stage growing rod. It may seem a daunting task but anterior growth ablation is fundamental. This cannot be done by antero-convex hemi-epiphysiodesis as Roaf’s long-term follow-up clearly showed (10). It does help a simple problem such as a hemi-vertebra but not with three-dimensional structural deformities. Removal of the apical growth plates has no great effect on longitudinal spinal growth as vertebrae are half adult size at the age of 2 and not far short of full adult size at the age of 10 (11,12), albeit with the bony nucleus surrounded by sizeable cartilaginous model. The deformity will not be adequately controlled by posterior surgery alone with the thoracic spine finishing up very much more deformed and appreciably shorter.

    It is also important to remember the growth velocity curve (13). The infantile growth spurt flattens out early on and remains flat until the adolescent growth spurt. That is why EDF casting is not continued much beyond the age of 3 because it is during this vital rapid growth period that control of the curve is crucial (1). Once the growth velocity flattens out then if casting has been successful the cast is removed because no significant curve progression would be anticipated until towards adolescence, several years later. Therefore surgery after the age of 5 can be delayed until a few years later although of course growth velocity and curve progression must be serially monitored.

    The authors also note that operating at a young age does increase complications but it is vitally important that surgery should be started as soon as the curve has shown significant progression potential, whether casted, as in the UK, or not. It is also suggested in this paper that casting can hinder chest wall development but that certainly is not either Mehta’s or my experience, with suitable windows cut out of the cast appropriately, and frequent cast changing with growth.

    The authors also suggest that in younger patients the curves may display greater flexibility but in point of fact that is exactly the opposite to what the situation is. When Mehta published one of her early papers on this subject the most important clinical factor concerning progression potential was curve rigidity (14). If the infant is suspended or, better still, put in the lateral decubitus position over the examiner’s knee with the convex side downward and the curve seems to correct well then this portends to a more benign prognosis with cast treatment likely be successful. The rigid curve notwithstanding should still undergo cast treatment as early as possible.

    The authors also differentiate between subcutaneous and submuscular metalwork. Having operated on so many infantile idiopathic progressive cases and reoperated them on an average of about 8 times, then one does build up a considerable experience of this procedure. I and my team do neither a subcutaneous or a submuscular rod placement but, rather, intramuscular so it does not have the disadvantage of being superficial nor the disadvantage of being subperiosteal.

    All in all early onset scoliosis is a very problematical condition and I am pleased that these leading authorities have once again drawn the world’s attention to it.

    References

    1. Mehta MA. Growth as a corrective force in the early treatment of progressive infantile scoliosis. J Bone Joint Surg [Br] 2005; 87-B: 1237-47.

    2. Millner PA, Helm R, Dickson RA. Early onset idiopathic scoliosis: Natural history and outcome. J Bone Joint Surg 1992: 74(B); Suppl III:303-4.

    3. Davies G, Reid L. Effect of scoliosis on growth of alveoli and pulmonary arteries and on right ventricle. Arch Dis Child 1971; 46: 623-632.

    4. Conner AN. Developmental anomalies and prognosis in infantile idiopathic scoliosis. J Bone Joint Surg [Br] 1969; 51-B: 711-713

    5. Mehta MH, Morel G. The non-operative treatment of infantile idiopathic scoliosis; In : Zorab PA and Siegler D (eds) Scoliosis. Proceedings of the Sixth Symposium 1979, London.

    6. Dickson RA. Conservative treatment for idiopathic scoliosis. J Bone Joint Surg [Br] 1985; 67-B:176-181.

    7. Branthwaite MA. Cardiorespiratory consequences of unfused idiopathic scoliosis. Br J Dis Chest 1986; 80: 360-369.

    8. Harrington PR. Treatment of scoliosis. Correction and internal fixation by spine instrumentation. J Bone Joint Surg [Am] 1962, 44-A: 491-610.

    9. Dickson RA, Lawton JO, Archer IA, Butt WP. The pathogenesis of idiopathic scoliosis. Biplanar spinal asymmetry. J Bone Joint Surg [Br] 1984, 66-B: 8-15.

    10. Andrew T, Piggott H. Growth arrest for progressive scoliosis combined anterior and posterior fusion of the convexity. J Bone Joint Surg [Br] 1985, 67-B: 193-197.

    11. Dimeglio A. Growth of the spine before age 5 years. J Pediatr Orthop Part B 1992; 1 (2): 102-107.

    12. Dimeglio A. Growth in pediatric orthopaedics. J Pediatr Orthop 2001; 21:549-555.

    13. Tanner JM. Growth at adolescence. 2nd ed. Oxford, Blackwell Scientific, 1962.

    14. Mehta M. The natural history of infantile idiopathic scoliosis. In: Zorab PA (ed) Scoliosis: Proceedings of a Fifth Symposium. London: Academic, 1977: pp 103-122.

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