Early Onset Scoliosis E-Book

• Herausgeber: Thieme
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 850

Veröffentlichungsjahr: 2015

Beschreibung

<p><strong><em>A comprehensive guide to modern treatment in a complex and evolving specialty</em></strong></p><p><strong>FIVE STARS from Doody's Star Ratings™</strong></p><p>Covering the spectrum of spinal deformity that occurs between birth and 10 years, early onset scoliosis (EOS) is an evolving specialty that faces unique challenges, especially in controlling the progression of the condition while allowing the growth of the developing spine, lungs and thorax. This important book was inspired by the inaugural early onset scoliosis meeting of spine surgeons and other medical professionals in Christ Church, Oxford, UK, in September 2011. It provides a complete picture of the field today, with topics ranging from spinal development and genetics to advances in medical management to breakthrough surgical techniques that offer promising new options for young patients.</p><p>Special Features</p><ul><li>Provides practical, evidence-based solutions to managing the full range of congenital, idiopathic, neuromuscular and syndromic conditions that present in early onset scoliosis</li><li>Describes pioneering surgical procedures, such as non-invasive, magnetically controlled growing rod systems that reduce the number of repetitive surgeries and hospitalizations</li><li>Explores such complex topics as surgical strategies for sitting comfort and features of optimal heelchair seating</li><li>Details treatments and outcome measures in diverse, multi-system disorders, such as early onset neuromuscular scoliosis</li><li>Highlights perioperative care and the vital role of physiotherapy in children with EOS</li><li>Introduces an EOS questionnaire that establishes validated, patient-reported data for outcome assessment</li></ul><p>Recognizing the importance of the multidisciplinary team approach in effective management, <em>Early Onset Scoliosis</em> offers the valuable international perspective of many leaders in the field. It is essential for orthopedic and pediatric surgeons,

Leseprobe

Early Onset Scoliosis

A Comprehensive Guide from the Oxford Meetings

Colin Nnadi, MBBS, FRCS (ORTH)

Consultant Spine SurgeonOxford University Hospitals NHS TrustOxford, United Kingdom

With contributions by

Ahmed Abdelaal, Behrooz A. Akbarnia, Ahmet Alanay, Andrew Baldock, Robert M. Campbell, Jr., Vivienne Campbell, Federico Canavese, Robert Crawford, Ozgur Dede, Evan M. Davies, Alain Dimeglio, Jean Dubousset, Hazem Elsebaie, Jeremy C.T. Fairbank, Adrian Gardner, Arvindera Ghag, Matthew J. Goldstein, Jaime A. Gómez, Michael Grevitt, N.S. Harshavardhana, Jayaratnam Jayamohan, Sandeep Jayawant, Nima Kabirian, David Marks, Richard E. McCarthy, S.M.H. Mehdian, Min Mehta, Jorge Mineiro, Ian W. Nelson, M.H. Hilali Noordeen, Howard Park, Nasir A. Quraishi, Harwant Singh, Laura Streeton, Anne H. Thomson, Athanasios I. Tsirikos, Peter D. Turnpenny, Michael G. Vitale, John K. Webb

240 illustrations

ThiemeStuttgart • New York • Delhi • Rio de Janeiro

Library of Congress Cataloging-in-Publication Data

Early onset scoliosis: a comprehensive guide from the Oxfordmeetings/[edited by] Colin Nnadi.      p.; cm.   Includes bibliographical references.   ISBN 978-3-13-172661-2 (alk. paper) – ISBN 978-3-13-   172671-1 (eISBN)   I. Nnadi, Colin, editor.   [DNLM: 1. Scoliosis–congenital. 2. Child. 3. Infant. 4.   Scoliosis–surgery. 5. Spine–abnormalities. WE 735]   RD771.S3   616.7'3–dc23

2014044547

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In memory of my father from whom I learnt so much.

–Colin Nnadi

Contents

Preface

Acknowledgments

Contributors

Part I The Growth and Development in Mammalian Spine

1 Frontier of the Impossible

Alain Dimeglio and Federico Canavese

2 Development of the Spine

Alain Dimeglio and Federico Canavese

3 The Genetics of Congenital Scoliosis and Abnormal Vertebral Segmentation

Peter D. Turnpenny

4 Respiratory Implications of Abnormal Development of the Spine

Robert M. Campbell, Jr.

Part II Congenital Deformities

5 Neuroaxial Anomalies

Jayaratnam Jayamohan

6 Congenital Deformities of the Spine

Athanasios I. Tsirikos

7 Surgical Treatment of Congenital Spinal Deformity

Athanasios I. Tsirikos

8 Surgical Treatment: The Nottingham Experience

John K. Webb and Nasir A. Quraishi

Part III Infantile Idiopathic Scoliosis

9 Surgical Intervention

Adrian Gardner and David Marks

10 Growth as a Corrective Force

Min Mehta (transcribed by Colin Nnadi)

11 The Mehta Casting Technique

Min Mehta (transcribed by Colin Nnadi)

Part IV The Experts’ View

12 Dual Growing Rod Treatment

Matthew J. Goldstein and Behrooz A. Akbarnia

13 Surgical Options: the Shilla Procedure

Richard E. McCarthy

14 The Experts’ View: A Narrative of the Great Debate

Colin Nnadi

15 Complications of Growing Rod Treatment

Nima Kabirian and Behrooz A. Akbarnia

Part V Neuromuscular Scoliosis

16 The Natural History of Neuromuscular Scoliosis

Vivienne Campbell

17 Assessing Outcomes in Neuromuscular Scoliosis

Michael Grevitt

18 Surgical Treatment and Outcomes

S.M.H. Mehdian and Nasir Quraishi

19 Best Surgical Strategies for Sitting Comfort

Robert Crawford

Part VI Syndromic Scoliosis

20 Medical Intervention and Advances in Medical Management

Anne H. Thomson and Sandeep Jayawant

21 Surgical Treatment of Syndromic Scoliosis

Ahmet Alanay and Ozgur Dede

22 Nonoperative Treatment of Syndromic Scoliosis

Ian W. Nelson

Part VII Perioperative Care

23 Infection and Bleeding

Evan M. Davies and Andrew Baldock

24 Perioperative Session: Neurologic Complications

Jorge Mineiro

25 Physiotherapy

Laura Streeton

Part VIII International Viewpoints

26 The North American Experience

Jaime A. Gómez, Howard Park, and Michael G. Vitale

27 The French Experience

Jean Dubousset

28 The Asian Experience

Harwant Singh

29 The North African Experience

Hazem Elsebaie

30 The Oxford Experience

Jeremy C.T. Fairbank and Arvindera Ghag

Part IX The Future

31 Clinical Trials: Holy Grail or Poisoned Chalice?

Colin Nnadi and Jeremy C.T. Fairbank

32 Is There a Gold Standard Surgical Option?

Ahmed Abdelaal and Colin Nnadi

33 Magnetic Growing Rods

N.S. Harshavardhana and M.H. Hilali Noordeen

34 Current Gaps in Knowledge: What Should Research Provide for the Future?

Richard E. McCarthy

Index

Preface

On the 8th of September 2011, a group consisting of 22 spine surgeons, two pediatricians, a geneticist, and an anesthetist gathered in Christ Church, Oxford, for the inaugural early onset scoliosis meeting. Delegates from Europe, North America, and as far afield as Australia and Asia attended.

This was the first meeting of its kind in the United Kingdom. It was a unique occasion for several reasons. First, the breadth of knowledge and experience available amongst invited faculty was immeasurable in value. Second, the great and the good, from the practicing to the retired, came out in force to produce one of the most entertaining meetings I have ever had the privilege to attend. Third, and by no means last, was the holistic theme that ran through the meeting. There were lectures from surgeons, geneticists, occupational therapists, and nurses. For the first time, we heard a parent's view of dealing with the social consequences of early onset spinal deformity. Members of the audience and faculty alike were able to share practical challenges and broach solutions.

The beautiful ambience of Christ Church, which has been home to countless philosophers, scientists, scholars, and statesmen, provided a salient backdrop for exciting debate and discussion.

Early onset scoliosis is an evolving specialty with more exciting developments still to come. There is much we do not know but what we are now aware of is the importance of controlling spinal deformity to potentiate the development of other organs such as the lungs and heart. We have a better understanding of spinal growth and its impact on the growing child. We have not found conclusive ways to treat this problem but there are interesting new strategies being developed all the time. The one theme that constantly rears its head in relation to this condition is the need for teamwork. Due to the often multi-systemic nature of early onset scoliosis, multi-disciplinary input is a prerequisite for good management. This philosophy formed the basis of the holistic theme of the meeting.

It is hoped that by reading this book the individual will develop a better understanding of what early onset scoliosis is and focus not on specific treatments but on principles to inform choice on best treatment.

This book is an ode to all those who contributed so much of their valuable time to increasing our understanding of a condition that afflicts those who have little or no say in the why, how, and when of treatment.

Colin NnadiOxford, United Kingdom

Acknowledgments

I wish to thank my contributors for sharing their inestimable knowledge in the making of this book. I also wish to thank all of the research team involved in the Magec Study, with special thanks to Andy Miles and David Mayers. Finally, a big thank you to Dr. Jo Richards and Jennifer Thorne for proof reading chapters.

Contributors

Ahmed Abdelaal, MBChB, MRCS, MScOxford UniversityHorton General HospitalOxford University Hospitals NHS TrustOxfordshire, United Kingdom

Behrooz A. Akbarnia, MDClinical ProfessorDepartment of Orthopaedic SurgeryUniversity of California, San DiegoPresident and FounderGrowing Spine FoundationSan Diego, California, United States

Ahmet Alanay, Prof. Dr.Professor of Orthopedics and TraumatologyAcibadem University Faculty of MedicineAcibadem Comprehensive Spine CentreMaslak, Istanbul, Turkey

Andrew Baldock, BSc (Hons), FRCA, FFICMConsultant Paediatric AnaesthetistSouthampton Children's HospitalUniversity Hospital SouthamptonSouthampton, United Kingdom

Robert M. Campbell, Jr., MDProfessor of Orthopaedic SurgeryThe University of Pennsylvania Perelman School ofMedicineDirectorThe Center for Thoracic Insufficiency SyndromeDivision of OrthopaedicsThe Children's Hospital of PhiladelphiaPhiladelphia, Pennsylvania, United States

Vivienne CampbellConsultant Paediatrician in NeurodisabilityChailey Heritage Clinical ServicesEast Sussex, United Kingdom

Federico Canavese, Prof. MD, PhDCentre Hospitalier Universitaire EstaingService de Chirurgie InfantileUniversité d'AuvergneFaculté de MédecineClermont-Ferrand, France

Robert Crawford, MBChB, FRCS, ChMConsultant Orthopaedic Spine SurgeonNorfolk & Norwich University HospitalNorwich, United Kingdom

Ozgur Dede, MDAssistant Professor of Orthopaedic SurgeryDivision of Pediatric OrthopaedicsChildren's Hospital of Pittsburgh of UPMCPittsburgh, Pennsylvania, United States

Evan M. Davies, BM, FRCS Ed (Tr&Orth)Consultant Orthopaedic Spinal SurgeonClinical LeadPaediatric Spinal UnitSouthampton Children's HospitalUniversity Hospital SouthamptonSouthampton, United Kingdom

Alain Dimeglio, Prof. MDUniversité de MontpellierFaculté de MédecineMontpellier, France

Jean Dubousset, MDProfessor of Pediatric OrthopaedicsAcadémie Nationale de MédecineParis, France

Hazem Elsebaie, FRCS, MDProfessor of Orthopedic SurgeryDepartment of OrthopedicsCairo UniversityVice PresidentEgyptian Scoliosis SocietyCairo, Egypt

Jeremy C.T. Fairbank, MA, MD, FRCSProfessor of Spine SurgeryConsultant Orthopaedic SurgeonOxford Spinal UnitOxford University Hospitals NHS TrustSpinal ServiceNuffield Orthopaedic CentreOxford, United Kingdom

Adrian Gardner, BM, MRCS, FRCS (T&O)Consultant Spinal SurgeonThe Royal Orthopaedic HospitalBirmingham, United Kingdom

Arvindera Ghag, MD, FRCS(C)Pediatric Spine SurgeryBC Children's HospitalVancouver, BC, Canada

Matthew J. Goldstein, MDClinical FellowSan Diego Center for Spinal DisordersLa Jolla, California, United States

Jaime A. Gómez, MDAssistant Professor, Pediatric Orthopedic and SpineSurgeryAlbert Einstein College of MedicineChildren's Hospital at MontefioreBronx, New York, United StatesSpine Surgery FellowHospital for Joint DiseasesNew York UniversityNew York, New York, United States

Michael Grevitt, MBBS, BSc, FRCS, FRCS (Orth)Consultant Spinal SurgeonCentre for Spinal Studies and SurgeryQueen's Medical Centre CampusNottingham University Hospitals NHS TrustNottingham, United Kingdom

N.S. Harshavardhana, MDClinical FellowTwin Cities Spine CenterMinneapolis, Minnesota, United States

Jayaratnam Jayamohan, BSc, MBBS, FRCS (SN) (Eng)Consultant Paediatric NeurosurgeonOxford University Hospitals NHS TrustHonorary Senior Clinical LecturerOxford UniversityJohn Radcliffe HospitalOxford, United Kingdom

Sandeep Jayawant, MD, FRCPCHConsultant Paediatric NeurologistOxford Children's HospitalOxford University Hospitals NHS TrustOxford, United Kingdom

Nima Kabirian, MDResearch FellowSan Diego Center for Spinal DisordersSan Diego, California, United States

David Marks, MBBS, FRCS, FRCS (Orth)Consultant Spinal SurgeonThe Royal Orthopaedic HospitalBirmingham, United Kingdom

Richard E. McCarthy, MDProfessorDepartments of Orthopaedics and NeurosurgeryUniversity of Arkansas for Medical SciencesArkansas Children's HospitalLittle Rock, Arkansas, United States

S.M.H. Mehdian, MD, MS (Orth), FRCS (Ed)Centre for Spinal Studies and SurgeryQueen's Medical Centre CampusNottingham, United Kingdom

Min Mehta, MD, FRCSConsultant Orthopaedic Surgeon (retired)Royal National Orthopaedic Hospital, NHS TrustLondon, United Kingdom

Jorge Mineiro, MD, PhD, FRCSEdProfessor of OrthopaedicsClinical DirectorHead, Orthopaedic DepartmentCUF Descobertas HospitalLisbon, Portugal

Ian W. Nelson, MBBS, FRCS, MCh (Orth)Bristol Orthopaedic Spine ServiceSouthmead Hospital and Bristol Royal Hospital forChildrenBristol, United Kingdom

Colin Nnadi, MBBS, FRCS (ORTH)Consultant Spine SurgeonOxford University Hospitals NHS TrustOxford, United Kingdom

M.H. Hilali Noordeen, FRCSConsultant Spinal SurgeonSpinal Deformity UnitDepartment of Spinal SurgeryRoyal National Orthopaedic Hospital NHS TrustLondon, United Kingdom

Howard Park, BSColumbia University Medical CenterDepartment of Pediatric Orthopaedic SurgeryMorgan Stanley's Children's Hospital of New YorkNew York, New York, United States

Nasir A. Quraishi, FRCS (Trauma & Orth)Consultant Spinal SurgeonHonorary Clinical Associate ProfessorCentre for Spinal Studies & SurgeryQueen's Medical CentreNottingham University Hospitals NHS TrustNottingham, United Kingdom

Harwant Singh, MD, FRCS, PhDConsultant Orthopaedic Spine SurgeonPantai HospitalKuala Lumpur, Malaysia

Laura Streeton, BSc (Hons), PG Cert (Paeds), MRes,MCSPSenior Paediatric PhysiotherapistNuffield Orthopaedic CentreOxford, United Kingdom

Anne H. Thomson, MD, FRCP, FRCPCHConsultant in Paediatric Respiratory Medicine(retired)Oxford Children's HospitalOxford University Hospitals NHS TrustOxford, United Kingdom

Athanasios I. Tsirikos, MD, FRCS, PhDConsultant Orthopaedic and Spine SurgeonHonorary Clinical Senior LecturerUniversity of EdinburghClinical LeadScottish National Spine Deformity CenterRoyal Hospital for Sick ChildrenEdinburgh, United Kingdom

Peter D. Turnpenny, BSc, MBChB, DRCOG, DCH, FRCP,FRCPCH, FRCPath, FHEAConsultant Clinical GeneticistRoyal Devon and Exeter HospitalHonorary Associate ProfessorExeter University Medical SchoolClinical Genetics DepartmentRoyal Devon and Exeter HospitalExeter, United Kingdom

Michael G. Vitale, MDAna Lucia Professor of Pediatric Orthopaedic SurgeryMS Children's Hospital of New YorkNew York, New York, United States

John K. Webb, FRCSConsultant Spine SurgeonCentre for Spinal Studies and SurgeryQueen's Medical Centre CampusNottingham, United Kingdom

Part 1 The Growth and Development in Mammalian Spine

1 Frontier of the Impossible

Federico Canavese and Alain Dimeglio

When you have excluded the impossible, whatever remains, however improbable, must be the truth.

—Sir Arthur Conan Doyle

Early onset scoliosis is one of the most challenging conditions in pediatric orthopedics and an important health issue. It is a condition with the potential to cause severe adverse consequences. The pathologic changes induced on a growing organism by an early onset spinal deformity can be dramatic and can, in the most severe cases, lead to death. A vertebral column that is not permitted to grow normally will affect the growth potential of the whole upper body, resulting in a short trunk, a disproportionate body habitus, and an underdeveloped thoracic cage (▶ Fig. 1.1).

Fig. 1.1Patients with untreated early onset scoliosis (infantile idiopathic scoliosis). The loss of sitting height is related to the severity of the deformity. A thoracic spine height of at least 18 to 22 cm is necessary to avoid thoracic insufficiency syndrome.

Pediatric orthopedic surgeons, by using the option of surgically managing young and very young children with early onset spinal deformity, have opened up a new perspective for spinal surgery. They have in effect broken down barriers that were previously felt to be insurmountable. Ingenuity has meant that management strategies have changed dramatically, shifting from a defensive attitude toward an offensive one. However, this audacious surgery is not without risk.

In young children with progressive deformity, there is a decrease of longitudinal growth and a loss of the normal proportionality of trunk growth. Abnormal growth leads to a deficit that sustains the deformity. As the spinal deformity progresses, by a “domino effect,” not only spinal growth but also the size and shape of the thoracic cage are modified. This distortion of the thoracic cage ultimately impairs lung development and cardiac function. Over time, the spine disorder changes in nature from a mainly orthopedic issue to a severe, systematic pediatric disease associated with thoracic insufficiency syndrome, cor pulmonale, and, in the most severe cases, death (▶ Fig. 1.2).

Fig. 1.2In young children with progressive deformity, distortion of the thoracic cage (a) leads to a decrease of longitudinal growth and (b) a loss of the normal proportionality of trunk growth.

Early spine fusion is not the answer for dealing with progressive, early onset spinal deformities. Arthrodesis in the thoracic spine at an early age does not address the impact of the deformity on the shape of the thoracic cage shape and development of the lung parenchyma, and it does not address the preservation of cardiopulmonary function. Moreover, early spinal fusion, especially in the thoracic region, is a cause of respiratory insufficiency and adds a loss of pulmonary function to the preexisting spinal deformity (▶ Fig. 1.3).

Fig. 1.3Early fusion is not able to control the progression of the deformity. This patient, an 11-year-old girl with atretic meningocele, diastematomyelia, and tethered cord, had multiple surgeries. The spinal deformity progressed, and the crankshaft phenomenon occurred. Arthrodesis in the thoracic spine at an early age does not address the impact of the deformity on the shape of the thoracic cage and development of the lung parenchyma, and it does not address the preservation of pulmonary function.

The ideal treatment of early onset scoliosis has not yet been identified; both clinicians and surgeons still face multiple challenges, including preserving the thoracic spine, thoracic cage, lung growth, and cardiac function without reducing spinal motion. However, patients with early onset scoliosis are a heterogeneous population, so that it is difficult to compare the outcomes of different management strategies in meaningful numbers of patients; in addition, there is a lack of outcome assessment tools for this complex group of patients.

Management strategies must consider the complete life span of the patient, and the effects of treatment on distorted spinal and chest growth must be considered. Before any treatment is started, a convincing answer to these three questions must be given:

What is the functional benefit of the treatment?

What is the potential morbidity of the treatment?

What quality of life can be anticipated?

1.1The Rib–Vertebral–Sternal Complex

In the concept of the rib–vertebral–sternal complex, a normal interaction occurs among the organic components of the spine, thoracic cage, and cardiorespiratory system.1,​2,​3 This complex encloses the three-dimensional thoracic cavity and tends to be an elastic structural model similar to a cube in shape. However, in the presence of scoliosis, the complex becomes flat, rigid, and elliptical and prevents the lungs from expanding. These deformities can be lethal in the most severe cases as a result of reciprocal interactions and influences among the various skeletal and organic components of the thoracic cage and cavity that are not well understood. The development of the thoracic cage and lungs is a complex process that requires perfect synergy among the various components of the rib–vertebral–sternal complex. Alterations in any of these elements affect and change the development and growth of the others. It must be remembered that the thoracic cage volume represents about 6% of its definitive volume at birth, about 30% by the age of 5 years, and about 50% by the age of 10 years (▶ Fig. 1.4). Moreover, between the age of 10 years and skeletal maturity, the thoracic cage volume doubles, and its volumetric growth ends on an upward trend.

Fig. 1.4The morphology of the thorax changes with growth, from a cylindrical shape at birth (a) to an ovoid shape at the age of 5 years (b).

To preserve thoracic motility and permit normal development of the respiratory tree, treatment should not focus only on the spine but should also consider the rib–vertebral–sternal complex as a whole.

1.2Growth Holds the Basics

Sitting height correlates strictly with trunk height and is the best indicator for monitoring thoracic cage and spinal growth. In children with severe spinal deformities, the loss of sitting height is related to the severity of the deformity. For this reason, it is important to monitor changes in sitting height rather than in standing height in children with progressive spinal deformities. Standing height does not always exactly correlate with the loss of trunk height in children with severe spinal deformities because it includes subischial height.

It is important to follow the stages of growth. Three periods can be identified: (1) between birth and 5 years of age, characterized by a significant spinal growth; (2) between 5 years of age and the beginning of puberty, characterized by a reduction in spinal growth (also known as the quiescent phase); (3) the pubertal growth spurt, characterized by a new increase of spinal growth (▶ Table 1.1).

Table 1.1

Growth of the T1-S1, T1-T12, and L1-L5 segments

Spinal segment

Age (years)

1

3

5

7

9

11

Pubertal spurt

T1-S1

2

1

1.8

T1-T12

1.3

0.7

1.1

L1-L5

0.7

0.3

0.7

Note: Values are expressed in centimeters and are average values. A perivertebral arthrodesis in the T1-S1 segment at 5 years of age results in a sitting height of 15 cm (10 cm in the thoracic spine and 5 cm in the lumbar spine).

Trunk growth is crucial between birth and 5 years of age because sitting height increases by 28 cm, whereas between 5 years of age and skeletal maturity the remaining trunk growth is 30 cm (▶ Fig. 1.5). Moreover, the T1-S1 segment increases by 10 cm between birth and 5 years of age and almost doubles in length between 5 years of age and skeletal maturity (▶ Table 1.2). It is therefore necessary to act fast, before pulmonary and cardiac alterations induced by a distorted spinal growth become irreversible. It is important to adapt management to growth rates. After the age of 5 years, the growth of the trunk decreases. Height increases by 2.5 cm and weight by 2.5 kg per year. This quiescent phase has to be used to stabilize the clinical situation because at the time of the pubertal growth spurt, the resumption of growth is going to worsen the spinal deformity. It is necessary to get ready for it and possibly to anticipate the need for a definitive surgery.

Fig. 1.5Evolution of the T1-T12 segment between birth and adulthood.

Table 1.2

Evaluation of the T1-T12 and L1-L5 spinal segments from birth to skeletal maturity

Developmental stage

Spinal segment

Males

Females

T1-T12

L1-L5

T1-T12

L1-L5

Newborn

11

7.5

11

7.5

Child

18

10.5

18

10.5

Pre-Adolescent

22

12.5

22

12.5

Adult

28

16

26

15.5

Note: Values are expressed in centimeters and are average values.

All growths are interrelated. Any abnormal growth, by a “domino effect,” leads to another abnormal growth. The irregular growth of vertebral bodies is the basis of a distorted development. Severe, progressive early onset spinal deformities lead to abnormal spine growth that alters thoracic and lung growth, which finally affects the cardiopulmonary system.1,​4

The goal of any treatment is to break this vicious cycle; it is necessary to correct all distortions secondary to distorted spinal growth as soon as possible: short height and disproportionate body habitus, underdeveloped thoracic cage and inability to breathe normally, low weight and cardiac dysfunction. Tachypnea, ventricular tachycardia, dyspnea, tracheomalacia, weight loss, and chronic obstructive pulmonary diseases are often more worrisome elements than the distortion of the vertebral column itself.

1.3Alveolarization: When Is It Complete?

Pediatric respiratory physiology is not well understood. It is difficult to investigate children younger than 5 years of age. Every day, a child exchanges 12,000 L of air. At birth, the lung parenchyma volume is 400 cc3; it is approximately 900 and 1,500 cc3 at ages 5 and 10 years, respectively, and about 4,500 cc3 for boys and 3,500 cc3 for girls at skeletal maturity.1,​2

Lung growth is a complex phenomenon in which different pulmonary structures and regions grow at different rates. At birth, the newborn has the same number of conducting airways as an adult. Tracheal caliber increases two- to threefold between birth and skeletal maturity. In contrast, the peripheral regions of the lung containing alveoli and pulmonary capillaries, also known as the acinar regions, undergo substantial postnatal growth and development.

Alveolarization is the process in which lung alveoli develop by multiplication. Once alveolar cell multiplication ceases, lung growth continues by alveolar cell expansion. It is estimated that about 30 to 50% of alveoli are present at birth; from the late fetal stage to 4 years of age, the number of alveoli grows by a factor of 10.

However, there is no agreement on when alveolarization stops. Some studies suggest that alveolar multiplication is completed by age 3 years, whereas others point out that alveolarization stops at age 8 years. Postmortem studies have shown that patients with early-onset deformities have fewer alveoli than expected, and that emphysematous changes in existing alveoli are present. These studies suggest that mechanical compression is not a factor in reducing the number of alveoli, and that this reduction is probably due to a premature cessation of alveolar proliferation. These data are currently being questioned as new findings are discovered with innovative study techniques such as electric impedance tomography, helium magnetic resonance imaging, and high resolution computed tomography.

The average number of alveoli reaches about 90 million at age 3 years and about 300 million during adulthood. These findings suggest that alveolar multiplication continues beyond early childhood. Moreover, experimental studies have shown that alveolarization continues beyond early life and into maturity in some mammals, and that it can be initiated by experimental pneumonectomy in mature animals. In humans, compensatory lung growth has been reported over a 15-year follow-up period after pneumonectomy in a 33-year-old woman for lung cancer. Moreover, it has been shown that Cobb angle correction does not correlate with either an increase in vital capacity or with a decrease in the spinal penetration index.

Evidence is beginning to accumulate that alveolarization may not be confined to early childhood, as previously thought, and may actually continue into maturity and beyond. Therefore, alveolarization during late childhood or adolescence may provide a repair mechanism for early insults to lung growth.5,​6

1.4 Surgery Is Part of a Programmed Action

Surgical treatment is not for every patient and not for every surgeon, and it should be done in specialized centers only. Surgery should be part of a well-structured multidisciplinary program. The orthopedic surgeon cannot act alone. Orthopedic surgeons experienced in spine disorders, anesthesiologists, pulmonologists, cardiologists, nutritionists, pediatricians, psychologists, physiotherapists, and pain specialists must work together to evaluate and handle these complex patients in order to obtain the best possible outcomes.

Before surgery is undertaken, four “presurgical” stages are needed to bring the surgical project to a favorable outcome.

Pediatric evaluation is needed to assess the child as a whole in order to identify and to treat, if possible, any comorbidity.

Nutritional evaluation. Correction of weight deficit is a priority as surgery is inevitably associated with a loss of weight. Classic prescriptions have a very limited effect, and it is necessary to understand that gastrostomy may be needed to improve weight.

Cardiorespiratory evaluation. Patients with cardiorespiratory deficits may require daily physiotherapy. It is important not to focus too much attention on surgery and not to leave aside respiratory physiotherapy. Physiotherapy plays an important role in stabilizing these patients before and after surgery. It can be compared with the almost daily re-education of a congenital clubfoot.

Orthopedic evaluation comes last. It is needed to evaluate the thoracic cage and spinal deformities and to choose the best treatment option (e.g., halo traction can improve the morphology of the spine to facilitate material implantation).

The fate of the child relies both on surgery and on pre- and postoperative care—hence the importance of precise evaluation and a multidisciplinary team of care providers.

1.4.1Surgical Options: There Is No Ideal Instrumentation

The ideal method of treating early onset scoliosis has not yet been identified. Advancements in growth-friendly procedures are providing physicians with multiple treatment options for children with early onset spinal deformities. However, because of the lack of evidence-based research, there is significant variation among surgeons’ opinions when treatment options are being considered. The only available study on surgeons’ preferences found a correlation between increasing curve size and the choice of growing rods over nonoperative treatment, rib-based distraction (vertically expandable prosthetic titanium rib), growth guidance (Shilla), and primary fusion.7 Moreover, a classification of growth-friendly procedures based on the mechanism by which they modulate spinal and chest wall growth has been developed in recent years. This classification identifies distraction-based, compression-based, and growth-guided techniques.

Growth-sparing surgery is not an isolated act; it is peppered with numerous faux pas. There is a clear correlation between complication rates and the number of surgical procedures. The amount of distraction-based growth tends to decrease over time, the gain in spinal length is minimal and may not be worth further lengthenings, proximal junctional kyphosis is a severe complication requiring complex revision surgeries, and neither the neurologic nor the infectious risks are negligible.

Modern techniques and instrumentation control only one plane of the deformity because distraction forces are applied either to the spine or to the thoracic cage. Over the past few years, several studies have demonstrated that nearly normal growth can be attained with the vertical expandable prosthetic titanium rib, growing rods, or a Shilla-type procedure. All of these techniques aim to restore normal spinal growth by controlling progression of the deformity. However, no instrumentation is currently available that is able to control the three-dimensional nature of early-onset spinal deformities.

Opening wedge thoracostomy can increase the thoracic volume by “opening” the thoracic cage in the way that a parasol is opened (parasol effect). The procedure avoids the median line, leaving the spine unaltered. It is important that this procedure be undertaken before the end of bronchial tree development. However, the technique has the drawbacks of stiffening the thoracic cage and wrinkling the muscles of the chest, resulting in an increase in the amount of energy needed to breathe.8

Growing rods applied on either side of the vertebral column are able to modulate growth and control the deformity in frontal and sagittal planes. However, they are unable to prevent proximal junctional kyphosis, and the gain achieved with repeated lengthening tends to decrease with each subsequent lengthening and over time.9

More recently, alternative growth guidance techniques have been developed so that spinal deformities can be treated without the necessity of repeated operative lengthenings. In one of them, two stainless steel rods are fixed to the corrected apex of the curve by pedicle screws. The system guides growth at the ends of dual rods, with the apex of the curve corrected, fused, and fixed to the rods. Vertebral growth occurs cephalad and caudad through extraperiosteal sliding pedicle screws. However, this surgical option remains relatively extensive, involving at least 6 to 8 of 17 vertebrae.10

The placement of screws in the neurocentral synchondrosis, vertebral body tethering, and nitinol stapling of the apical vertebrae are other surgical interventions currently under development. The rationale behind these procedures is to limit spine growth asymmetrically, maintain spinal motion, preserve intervertebral disk physiology, and prevent the need for spinal fusion.11,​12

Magnetically controlled, remotely distractible growing rod systems have been developed to reduce the number of repetitive surgeries under general anesthesia, decrease the number of hospitalizations, facilitate outpatient rod distraction, and reduce the number of wound complications and psychological problems. Moreover, distraction is gradual and performed at regular intervals with the child in a conscious state. Gradual and almost daily distraction is probably the most effective surgical procedure. It is very close to the principles of distraction osteogenesis introduced by Ilizarov about four decades ago.13,​14 This technique still presents some technical imperfections that need to be improved.

1.4.2 The Dark Side of Surgery

Surgery in patients with early onset scoliosis has a high morbidity rate. This is a major concern. Repetitive surgeries worsen the risk of complication, and it has been shown that any additional, unplanned intervention increases the risk for a complication by more than 20%. The structure of the vertebra contributes to the challenge of surgery: reduced size, the presence of osteoporosis, and the presence of cartilage that characterizes the “infantile” vertebra. At the age of 5 years, only one-third of the vertebral volume is ossified.

The rate of complications ranges from 8 to 50%; skin problems, wound and anesthetic complications, device migration, fractures, autofusion, hardware failure, infections, and decompensation have all been reported. Repeated hospitalizations for lengthenings and for unplanned surgical procedures increase the child’s time away from school and can have repercussions on the child’s psychological well-being.15

Overall, the risk of developing a complication is increased by a vital capacity of less than 50%, a Cobb angle of more than 50 degrees, kyphosis of more than 60 degrees, weight less of more than 20 kg, comorbidities, and a higher number of previous surgeries (▶ Table 1.3). Repetitive surgeries can induce spontaneous fusion; autofusion of ribs and vertebral bodies may then make definitive surgery more challenging.16

Table 1.3

Assessment of surgical risk

Surgical risk

Walking ability

Weight

Cardiac function

Respiratory function (VC)

Sleep

Comorbidities

Average

Ambulatory

>40 kg

Normal

Normal

Normal

No

Increased

Ambulatory with aid

20–40 kg

Reduced

Reduced, but >50%

Hypersomnia

High

Nonambulatory

<20 kg or obese

Significantly impaired

<50%

Nocturnal hypercapnic hypoventilation, obstructive sleep apnea

Yes

Abbreviation: VC, vital capacity.

Note: Besides neuromuscular pathology, factors such as walking ability, nutritional status, cardiopulmonary function, and the presence of other comorbidities must be taken into account before surgery in order to minimize surgical risk. Morbidity is higher in nonambulatory patients with reduced weight and impaired cardiopulmonary function.

1.4.3 From Minimally to Maximally Invasive Surgery

At first, the goal is to limit surgery as much as possible. Because of repetitive surgical procedures, however, the surgeon gradually operates on almost the whole spine and forgets the need to spare levels as well as spinal motion. From surgical procedure to surgical procedure, from one complication to another, the surgeon stiffens the spine. Obsessed with repeating surgical procedures, the surgeon tends to forget that preservation of the vertebrae is essential for spinal growth. In fact, some procedures do stiffen about one-half of the T1-S1 segment without the surgeon realizing it (▶ Fig. 1.6 and ▶ Fig. 1.7). It is important not to forget that between T1 and S1 there are only 18 vertebrae!

Fig. 1.6Remaining T1-S1 growth in boys. Values are averages and expressed in centimeters.

Fig. 1.7Remaining T1-S1 growth in girls. Values are averages and expressed in centimeters.

In very young children, surgery should be limited as much as possible, and extensive arthrodesis of the spine should be avoided. Nevertheless, the surgeon can use hybrid constructs, such as growing rods in the back and staples at the apex of the deformity. Moreover, the surgeon can modify the instrumentation depending on the age of the patient, using smaller devices in younger children and bulkier instrumentation in older patients. It is fundamental that before any surgical program is started, these principles must be fully understood by everyone, surgeon included.

1.5Serial Casting: Don’t Put the Finger in the Gear

Challenging the growing spine means preserving the thoracic spine, thoracic cage, and lung growth without reducing spinal motion. The morbidity related to surgical procedures has favored the return of conservative treatment—that is, serial casting.

Casting is a nonoperative option that can be considered in the management of the young and very young child with early onset progressive spinal deformity. It can be used either as a delaying tactic, in order to prevent progression of the deformity for several years before definitive fusion, or as a definitive treatment option. It has been shown that in patients treated aggressively with casting before the age of 20 months for curves averaging 30 degrees, scoliosis was stabilized and/or reduced to 10 degrees or less at skeletal maturity. On the other hand, children undergoing cast treatment after the age of 30 months for curves averaging 50 degrees did not gain significant correction, although their spinal curvature did not progress.17 The main advantage of casting is that the spine is left alone. Moreover, it helps the surgeon not to put a finger in the spinal gear! The implantation of growth-sparing devices, near and/or at the level of the spine, affects spinal growth as demonstrated by both experimental and clinical studies.1,​2,​3,​18 Even if growth-sparing devices are implanted at a reasonable distance from the spine, autofusion of ribs and vertebral bodies may make definitive instrumented fusion more challenging for the surgeon and riskier for the patient, and the end result is less satisfactory for everybody.16

Unlike surgery, serial casting is an alternative that does not negatively affect or further alter spinal growth, and it can be used as a “positive” corrective force because it plays an important role in delaying or even eliminating the need for growth-sparing surgery. However, serial casting is not indicated for all types of early onset spinal deformities. At first sight, casting may appear like a constrictive force applied to the thoracic cage, limiting its expansion. Indeed, if well moulded, a cast does not compress the thoracic cage, and respiratory movements are allowed. These data can be considered to promote conservative means of treatment in young and very young patients, to allow expansion of the thoracic cage, lung growth, and cardiac function.

1.6Crankshaft Phenomenon Is a Constant Enemy

In the crankshaft phenomenon, a spinal deformity progresses when the anterior portion of the spine continues to grow while the posterior portion is restricted by arthrodesis (▶ Fig. 1.3). The best way of controlling a pathologic spinal segment is to control all growth cartilages included in the pathologic zone. Nevertheless, it is very important for a surgeon to consider the state of skeletal maturity and the amount of growth remaining in the spinal segment to be fused. The Crankshaft phenomenon is manifested not only by an increase in the Cobb angle but also by a worsening of spinal imbalance, increased kyphosis, and progression of the spinal penetration index, characterized by penetration of the apical portion of the deformity inside the thoracic cage.

1.7To Distract Kyphosis Is a Paradox

Sagittal plane correction is critical to the long-term success of scoliosis surgery. Proximal junctional kyphosis can occur during the treatment of early onset scoliosis, regardless of the preferred surgical procedure. It can become severe enough to require complex secondary interventions. Today, recognized independent risk factors for proximal junctional kyphosis are preoperative thoracic hyperkyphosis, proximal thoracic kyphosis, and a more proximal level of lower instrumented vertebrae (▶ Table 1.4).

Table 1.4

How to avoid proximal junctional kyphosis according to published data

Do/do not

Vertical expandable prosthetic titanium rib (VEPTR)

Growing rods

Do

Increase the number of anchors

Contour the proximal portion of the rod

Do

Bypass the apex of the kyphosis

Use gentle dissection

Do not

Apply proximal fixation below T4 (fourth rib)

Apply proximal fixation below T4

Do not

Make distal fixation too proximal; extend to pelvis if needed

Use hypercorrection

A flexible spine does not predict good outcomes.

Is it possible to avoid proximal junctional kyphosis? To answer this enigma, we should first understand where proximal junctional kyphosis comes from. Is proximal junctional kyphosis an issue limited to the spine? Or is it favored by underlying medical issues? In other words, despite the presence of early onset spinal deformity, are some patients more at risk for developing proximal junctional kyphosis than others?

Mechanical and genetic factors can be responsible for proximal junctional kyphosis. The restoration of normal sagittal alignment is one of the fundamental goals in scoliosis correction surgery, and rod pre-contouring is a standard procedure in almost all modern correction techniques for sagittal alignment control. However, in patients with early onset spinal deformities, it is not always possible to adapt the instrumentation to the spinal anatomy, in particular in the cervical region. When confronted with kyphosis, surgeons tend to increase the number of proximal and distal anchors.

When dealing with patients who have neurofibromatosis, chondrodystrophy, or spondyloepiphyseal dysplasia, the physician must remember that the cervical spine is pathologic. In those cases, it is wiser to treat the cervical spine first and then focus on the spinal deformity located below. It is necessary to know how to handle the cervical spine before treating the thoracic deformity in order to minimize potential neurologic complications.

Moreover, it is important to note that the surgeon is sometimes in a “biomechanical illegality.” Certain kyphoscoliotic deformities are going to deteriorate when distraction is applied to correct the scoliotic portion of the spine; kyphosis does not tolerate distraction! The sagittal profile tends to deteriorate when repetitive distraction surgeries are performed.

1.8 The More You Lengthen, the Less You Lengthen

The economic concept outlined by the law of diminishing returns has been transposed to pediatric orthopedics. This law postulates that with constant factors of production, when new employees are hired, the marginal product of an additional employee will at some point be less than the marginal product of the previous employee. Therefore, from this point on, each additional employee will provide less and less return. In early onset spinal deformities treated with growing systems, the picture is similar. The gain achieved by repeated lengthening tends to decrease with each subsequent lengthening and over time. Successful initial lengthening of the spine appears to be a shortcut to unsuccessful subsequent lengthenings. This phenomenon is likely due to progressive stiffness or autofusion of the spine caused by repetitive and sudden distractions.19

Each distraction has to have a positive effect on sitting height. Sitting height correlates strictly with trunk height. Therefore, it is a more objective parameter than standing height for the assessment of spinal growth. Standing height is less reliable because lower extremity growth may mask ineffective distractions.

1.9What about Definitive Fusion?

The heterogeneity that characterizes growth-friendly techniques also applies to the management of children who have reached the end of the expansion phase of their growing instrumentation.20 Final treatment varies with the underlying diagnosis, the condition of the spine and chest wall, and the instrumentation used.

Definitive fusion stops further spinal growth and achieves definitive correction. It becomes appropriate when patients have achieved sufficient thoracic spine length and thoracic cage volume. The timing of the procedure remains controversial, but in general, patients who are at least 10 years of age have completed the greatest part of their thoracic growth.

At the beginning of puberty, the T1-S1 segment still has to grow about 7 cm, of which approximately 4 cm is at the level of the thoracic spine and 3 cm is at the level of the lumbar spine. It is wiser to lose some growth than to have the deformity progress. Moreover, correction of the deformity compensates for the loss of height due to spinal fusion. Anticipation is sometimes the best strategy.

1.10 Heterogeneity of Etiologies, Diversity of Strategies

Patients who have early onset scoliosis are a heterogeneous population characterized by multiple etiologies. There is no single management strategy. There is no absolute truth. It is necessary to adapt treatment to each patient’s need. Children with neuromuscular scoliosis at a young age have a set of challenges and problems, as well as treatment options, different from those of children with infantile idiopathic scoliosis or children with syndromes. All of these children have acquired scoliosis at an early age, but the manifestations, complications, and outcome of treatment vary. Age is another parameter that must be taken into account. Clearly, the 17-month-old child, the 5-year-old child, and the 9-year-old child with a spinal deformity are different facets of the problem and represent different opportunities for care.

Surgery must be finely shaded. In other words, a child with infantile idiopathic scoliosis can be treated by serial casting, a child with thoracic insufficiency syndrome due to congenital scoliosis and fused ribs may mostly benefit from open thoracostomy and rib distraction, and a child with neurologic scoliosis may be treated with dual growing rods. On the other hand, in the case of a child with cerebral palsy and a collapsing spine, it may be worth waiting until the patient reaches age 10 and then perform a definitive fusion. In patients with low weight (e.g., Rett syndrome), it is not worth waiting for the pubertal growth spurt because their low body weight prevents puberty. On the other hand, patients with one- or two-level congenital malformations can benefit from limited early fusion; in this case, the surgeon is less concerned about definitive and limited surgery.

1.11 Conclusion: Don’t Be Obsessed by the Centimeter

Treatment of the growing spine is a unique challenge. Patients with early onset spinal deformities are young, with significant remaining growth. Every failure causes psychological trauma for the family.

Managing the growing spine means preserving the thoracic spine, thoracic cage, and lung growth without reducing spinal motion. Have we the means of our ambitions? Probably not.

Obsession with the centimeter does not have to distract the surgeon from the fundamental priorities:

What is the clinical picture?

What is the annual weight gain? As a rule of thumb, annual weight gain should be 2.5 kg between 5 years of age and the beginning of the puberty.

What is the annual increase in sitting height? In principle, between 5 and 11 years of age, the sitting height should increase annually by 2.5 cm.

What is the evolution of the vital capacity?

Finally, the objectives to be achieved are the following:

An improved clinical picture;

A weight gain of about 2.5 kg per year;

A thoracic spine height of 18 to 22 cm or more, which is necessary to avoid severe respiratory insufficiency;

A vital capacity of at least 50%.

The ultimate goal of treatment is to improve the natural history of the patient’s spinal deformity as well as the patient’s quality of life, and to have these sick children become independent adults. The contract with families must be clear. This is a long-term treatment. It is necessary to explain the obstacles to be overcome and not to underestimate the risks.

It is also important to understand how to prioritize a patient’s needs. There is a short-term priority, in which the main goal is to stop progression of the spinal deformity. There is a midterm priority, in which the primary objective is to improve cardiorespiratory function and weight. There is a long-term priority, in which the ultimate goal is to have these patients become independent adults with an acceptable quality of life. We should prevent a child from becoming the end result of a juxtaposition of surgical procedures.

The path that remains to be traveled is still long, but new perspectives in the field of respiratory physiology, pediatric nutrition, and surgery are on the horizon.

Nothing is impossible. We call impossible what human beings take a long time to achieve.

—Albert Camus

References

[1] Dimeglio A, Canavese F. The growing spine: how spinal deformities influence normal spine and thoracic cage growth. Eur Spine J 2012; 21: 64‐70 PubMed

[2] Canavese F, Dimeglio A, Volpatti D et al. Dorsal arthrodesis of thoracic spine and effects on thorax growth in prepubertal New Zealand white rabbits. Spine 2007; 32: E443‐E450 PubMed

[3] Canavese F, Dimeglio A, Granier M et al. Arthrodesis of the first six dorsal vertebrae in prepubertal New Zealand white rabbits and thoracic growth to skeletal maturity: the role of the “rib-vertebral-sternal complex.” Minerva Ortop Traumatol 2007; 58: 369‐378

[4] Dimeglio A. Growth of the spine before age 5 years. J Pediatr Orthop B 1993; 1: 102‐107

[5] Narayanan M, Owers-Bradley J, Beardsmore CS et al. Alveolarization continues during childhood and adolescence: new evidence from helium-3 magnetic resonance. Am J Respir Crit Care Med 2012; 185: 186‐191 PubMed

[6] Butler JP, Loring SH, Patz S, Tsuda A, Yablonskiy DA, Mentzer SJ. Evidence for adult lung growth in humans. N Engl J Med 2012; 367: 244‐247 PubMed

[7] Yang JS, McElroy MJ, Akbarnia BA et al. Growing rods for spinal deformity: characterizing consensus and variation in current use. J Pediatr Orthop 2010; 30: 264‐270 PubMed

[8] Campbell RM Jr. Smith MD, Mayes TC et al. The effect of opening wedge thoracostomy on thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis. J Bone Joint Surg Am 2004; 86-A: 1659‐1674 PubMed

[9] Thompson GH, Akbarnia BA, Campbell RM Jr. Growing rod techniques in early-onset scoliosis. J Pediatr Orthop 2007; 27: 354‐361 PubMed

[10] McCarthy RE, Luhmann S, Lenke L, McCullough FL. The Shilla growth guidance technique for early-onset spinal deformities at 2-year follow-up: a preliminary report. J Pediatr Orthop 2014; 34: 1‐7 PubMed

[11] Zhang H, Sucato DJ. Unilateral pedicle screw epiphysiodesis of the neurocentral synchondrosis. Production of idiopathic-like scoliosis in an immature animal model. J Bone Joint Surg Am 2008; 90: 2460‐2469 PubMed

[12] Betz RR, Kim J, D’Andrea LP, Mulcahey MJ, Balsara RK, Clements DH. An innovative technique of vertebral body stapling for the treatment of patients with adolescent idiopathic scoliosis: a feasibility, safety, and utility study. Spine 2003; 28: S255‐S265 PubMed

[13] Cheung KM, Cheung JP, Samartzis D et al. Magnetically controlled growing rods for severe spinal curvature in young children: a prospective case series. Lancet 2012; 379: 1967‐1974 PubMed

[14] Wick JM, Konze J. A magnetic approach to treating progressive early-onset scoliosis. AORN J 2012; 96: 163‐173 PubMed

[15] Bess S, Akbarnia BA, Thompson GH et al. Complications of growing-rod treatment for early-onset scoliosis: analysis of one hundred and forty patients. J Bone Joint Surg Am 2010; 92: 2533‐2543 PubMed

[16] Lattig F, Taurman R, Hell AK. Treatment of early onset spinal deformity (EOSD) with VEPTR: a challenge for the final correction spondylodesis: a case series. J Spinal Disord Tech 2012 [Epub ahead of print]. PubMed

[17] Mehta MH. Growth as a corrective force in the early treatment of progressive infantile scoliosis. J Bone Joint Surg Br 2005; 87: 1237‐1247 PubMed

[18] Karol LA, Johnston C, Mladenov K, Schochet P, Walters P, Browne RH. Pulmonary function following early thoracic fusion in non-neuromuscular scoliosis. J Bone Joint Surg Am 2008; 90: 1272‐1281 PubMed

[19] Sankar WN, Skaggs DL, Yazici M et al. Lengthening of dual growing rods and the law of diminishing returns. Spine 2011; 36: 806‐809 PubMed

[20] Akbarnia BA, Campbell RM, Dimeglio A et al. Fusionless procedures for the management of early-onset spine deformities in 2011: what do we know? J Child Orthop 2011; 5: 159‐172 PubMed

2Development of the Spine

Alain Dimeglio and Federico Canavese

Only a perfect knowledge of normal growth parameters allows a thorough understanding of the pathologic changes induced in a growing organism by an early onset spinal deformity. As the spinal deformity progresses, not only is spinal growth affected; by a “domino effect,” the size and shape of the thoracic cage are modified as well. This distortion of the thorax interferes with lung development. Over time, the spine disorder changes in nature from a mainly orthopedic issue to a severe, systemic pediatric disease causing thoracic insufficiency syndrome, cor pulmonale, and, in the most severe cases, death.

The growing spine is a mosaic of growth plates characterized by changes in rhythm. During growth, complex phenomena follow one another in very rapid succession. These events are well synchronized to maintain harmonious limb and spine relationships, as growth in the various body segments does not occur simultaneously in the same magnitude or at the same rate. The slightest error or modification can lead to a malformation or deformity, with negative effects on standing and sitting height; the shape, volume, and circumference of the thoracic cage; and lung development.1,​2

2.1Clinical Examination and Biometric Measurements

Growth holds the basics, and any surgical strategy should be adjusted according to the ratio between remaining growth and elapsed growth (▶ Table 2.1).

Table 2.1

Growth is a change in proportion

Developmental stage

Sitting height

Lower extremities

Head

Trunk

Fetus (early pregnancy)

50%

32%

18%

Fetus (late pregnancy)

35%

40%

25%

Newborn

25%

40%

35%

Infant

23%

37%

40%

Child

20%

35%

45%

Pre-Adolescent

18%

34%

48%

Adult

13%

40%

47%

Note: The ratio of the sitting height to the length of the lower extremities varies with age; it is 4.5 during early pregnancy, 3 during late pregnancy, 1.9 at birth, 1.3 during childhood, and 1 at skeletal maturity.1,​2,​3,​4

A height gauge, scales, a metric tape, and a bone age atlas are required at the time of consultation. All growths are synchronized, but each one has its own rhythm (▶ Fig. 2.1). A thorough analysis of the standing and sitting height, arm span, weight, thoracic perimeter, T1-S1 spinal segment length, and respiratory function helps the surgeon to plan the best treatment at the right time. Therefore, these measurements should be repeated and carefully recorded at regular intervals to provide a real-time image of growth and charts that facilitate decision making. A clinical examination every 4 to 6 months allows the clinician to assess the growth velocity of the child and the different body segments easily.1,​2

Fig. 2.1All growths are synchronized, but each one has its own rhythm. Growths do not progress at the same pace. At 5 years of age, the increases in weight and thoracic volume remain limited relative to the other growth indicators. At 5 years of age, children have reached 26% of their final weight but between 66% and 70% of their final sitting height.

2.1.1Standing Height

The gain in standing height is approximately 25 cm during the first year of life and about 12.5 cm during the second year. Between the ages of 2 and 3 years, the gain in standing height is approximately 9 cm annually, and between the ages of 3 and 4 years, the gain in standing height is approximately 7 cm annually. At 5 years of age, the standing height increases by 5 to 5.5 cm each year in both boys and girls. At the beginning of puberty, the average remaining growth in the standing height is about 22.5 cm for boys (13%) and 20.5 cm for girls (11%).

Growth velocity is the best indicator of the beginning of puberty, on which so many decisions rest. The first sign of puberty is an increase in the rate of growth in the standing height to more than 0.5 cm per month or more than 6 to 7 cm per year.1,​2,​3,​4 Growth charts show that a standing height growth velocity of more than 6 cm per year in girls and more than 7 cm per year in boys is evidence that the patient is within his or her greatest growth spurt.1,​2,​3,​4 This rapid and significant increase in the growth rate is called peak height velocity or acceleration phase. During this phase, the average remaining growth in the standing height is about 16.5 cm for boys and 15 cm for girls. The first 2 years of puberty, characterized by significant growth, are followed by 3 years of a gradual and steady reduction in the growth rate, the so-called deceleration phase, during which the average remaining growth in the standing height is about 6 cm for boys and 5 cm for girls.1,​2,​3

In 77% of boys, the first physical sign of puberty is testicular growth, which occurs on average 3.5 years before adult height is attained. In 93% of girls, the first physical sign of puberty occurs about 2 years before menarche, and final height is usually achieved 2.5 to 3 years after menarche.1,​2,​3,​4

The standing height is a global marker comprising two components: sitting height and subischial height. Because the trunk and the subischial region often grow at different rates and at different times, the standing height does not always exactly correlate with a loss of trunk height in children with severe spinal deformities.1,​2,​3,​4

2.1.2Sitting Height

The sitting height correlates strictly with trunk height and is on average about 34 cm at birth; it is 88 cm at the end of growth for girls and 92 cm at the end of growth for boys. In children with severe spinal deformities, the loss of sitting height is related to the severity of the deformity. For this reason, it is important to monitor changes in sitting height rather than in standing height in children with progressive spinal deformities. During the first 3 years of life, or in a child with a neurologic disorder or a collapsing spine, it is recommended to measure the sitting height with the child in a supine position.

Growth is a succession of acceleration and deceleration phases comprising three periods. The first period is from birth to age 5 and is characterized by a gain in sitting height of 27 cm, with a gain of 12 cm occurring during the first year of life. The second period is from age 5 to 10 years and is a quiescent phase in which sitting height increases by 2.5 cm per year. The third period is characterized by a gain in sitting height of about 12 cm and corresponds to puberty.1,​2,​3 During peak height velocity or acceleration phase,4 the average remaining growth in the sitting height is about 12.5 cm for boys and about 11.5 cm for girls (▶ Fig. 2.2, ▶ Fig. 2.3, ▶ Fig. 2.4). The average remaining growth in the sitting height during the deceleration phase is about 4 cm for boys and 3.5 cm for girls.1,​2,​3,​4

Fig. 2.2Percentage of remaining sitting height growth in boys (gray) and girls (white). Sitting height growth is completed 2 years earlier in girls than in boys on average.

Fig. 2.3Sitting height gain in boys. Values are expressed in centimeters and are average values.1,​2,​3 In boys, the pubertal spurt occurs between 13 and 15 years of age.

Fig. 2.4Sitting height gain in girls. Values are expressed in centimeters and are average values.1,​2,​3 In girls, the pubertal spurt occurs between 11 and 13 years of age.

2.1.3Weight

Weight is a useful parameter for evaluating growth and increases 20-fold from birth to skeletal maturity. At 5 years of age, weight is approximately 20 kg; it is 30 kg by 10 years and reaches 60 kg or more by 16 years. In particular, weight usually doubles during the pubertal spurt, and each year of puberty corresponds to a weight increase of about 5 kg. This information should be kept in mind when a child is treated with a brace. Moreover, in a patient whose weight is 10% or more above normal, a scoliosis brace may be less effective than in a patient whose weight is within 10% above normal.1,​2,​3,​4

Growth energy requirements during the first 3 years of life are enormous and much greater than those of adults: 110 calories vs. 40 calories per kilogram per day; 2 g vs. 1 g of proteins per kilogram per day; and 150 mL vs. 5 mL of water per kilogram per day. Moreover, skeletal mineralization alone requires the storage of 1 kg of calcium between birth and adulthood.