NS Harshavardhana, TJ Guillaume,

MHH Noordeen, JH Perra

What is Magical about Magnet driven Growth Rods (MdGR) Used for Early-onset Scoliosis (EOS)?

Presenter: NS Harshavardhana No Relationships

Co-Authors: TJ Guillaume No RelationshipsMHH Noordeen K2M(c), Ellipse Tech(b,c),

Stryker spine (b,c)JH Perra Medtronic(b,c)

a. Grants / Research Supportb. Consultant / Royaltiesc. Stock / Shareholderd. Speakers’ Bureaue. Other Financial Support

What is Magical about Magnet driven Growth Rods (MdGR) Used for Early-

onset Scoliosis (EOS)

ICEOS 2015 Boston - MA; USA 19-20th Nov 2015

Authors Disclosure Information

Background: MdGRs

Novel implant used in the surgical treatment of EOS Considered to be a game-changer in EOS Rx

Recently approved by US-FDA for EOS: Two years

Europe using it over the past Five years

Substitutes the need for repetitive anaesthesia and invasive lengthening by office-based expansion

Aims and Objectives To undertake comprehensive systematic review

with meta-analysis of all published MdGRs

Prospective, Retrospective or / & Case series

At least 4 patients & a minimum of 3 distractions

Report surgical results of MdGRs Compare single rods vs. dual rods Sagittal profile and complications Pulmonary function and cost-utility aspects

Materials and Methods

All published full-text articles in English: 2012-2015(up to 1st June 2015)

Inclusion criteria: Should have used MdGRs More than 3 patients (JBJS-Am Case-Connector) At least 3 distractions (follow-up)

Exclusions: Any study which did NOT meet the above criteria i.e.:- That was not published as full-text article (i.e. abstracts) In language other than English

Included Studies in Meta-analysisClinical studies1. Cheung KM, Cheung JP, Samartzis D, Mak KC, Wong YW, Cheung WY, et al. Magnetically controlled growing rods for severe spinal curvature in young children: a prospective case series. Lancet. 2012; 379(9830): 1967-74.2. Akbarnia BA, Cheung K, Noordeen H, Elsebaie H, Yazici M, Dannawi Z, et al. Next generation of growth-sparing techniques:

preliminary clinical results of a magnetically controlled growing rod in 14 patients with early-onset scoliosis. Spine. 2013; 38(8): 665-70.3. Dannawi Z, Altaf F, Harshavardhana NS, El Sebaie H, Noordeen H. Early results of a remotely-operated magnetic growth rod in early-onset scoliosis. The Bone & Joint Journal. 2013; 95-b(1): 75-80.4. Akbarnia BA, Pawelek JB, Cheung KMC, Demirkiran G, Elsebaie H, Emans JB, et al. Traditional Growing Rods Versus Magnetically Controlled Growing Rods for the Surgical Treatment of Early-Onset Scoliosis: A Case-Matched 2- Year Study. Spine Deformity. 2014; 2(6): 493-7.5. Hickey BA, Towriss C, Baxter G, Yasso S, James S, Jones A, et al. Early experience of MAGEC magnetic growing rods in

the treatment of early onset scoliosis. European spine journal 2014; 23 Suppl 1: S61-5.

USG guided measurement of distraction gained6. Stokes OM, O'Donovan EJ, Samartzis D, Bow CH, Luk KD, Cheung KM. Reducing radiation exposure in early-onset scoliosis surgery patients: novel use of ultrasonography to measure lengthening in magnetically-controlled growing rods. The spine journal 2014; 14(10): 2397-404.7. Yoon WW, Chang AC, Tyler P, Butt S, Raniga S, Noordeen H. The use of ultrasound in comparison to radiography in

magnetically controlled growth rod lengthening measurement: a prospective study. European spine journal 2014 [Epub ahead of print].

Cost-utility analysis8. Charroin C, Abelin-Genevois K, Cunin V, Berthiller J, Constant H, Kohler R, et al. Direct costs associated with the management of progressive early onset scoliosis: Estimations based on gold standard technique or with magnetically controlled growing rods. Orthopaedics & Traumatology: Surg & Research. 2014; 100(5): 469-74.9. Rolton D, Richards J, Nnadi C. Magnetic controlled growth rods versus conventional growing rod systems in the treatment

of early onset scoliosis: a cost comparison. European spine journal 2014 [Epub ahead of print].

Pulmonary function10. Yoon WW, Sedra F, Shah S, Wallis C, Muntoni F, Noordeen H. Improvement of pulmonary function in children with early-

onset scoliosis using magnetic growth rods. Spine. 2014;39(15):1196-202.

Results 73 children operated for EOS & with a minimum

follow-up of 9 months (mean: 1.6 yrs)

Five clinical studies: 3 single center (Hong Kong / London / Cardiff) and 2 multi-centric studies

33♂ & 40♀ (1st Jan 2010 – 15th May 2015)

23 single rods(SR) vs. 50 dual rods(DR)

Etiology: 1. Idiopathic (29) 3. Congenital(7)

2. Neuromuscular(20) 4. Syndromic(12)

5. Neurofibromatosis(5)

Demographics & Radiological parameters

Forest plots: Cobb ^le & T1-S1 Length

All five clinical studies reported a statistically significant improvement with scoliosis correction and T1-S1 length gain

Complications: 1. Wound infections: 4 superficial (none deep)

2. Rod fractures: 3 (2 SR & 1 DR)

3. Loss of distraction achieved: 10 pts

4. Anchor pull-out: 3 pts (2 proximal & 1 distal)

5. Proximal junctional kyphosis: 2 pts.

Forest plots for single vs. dual Rods

Cobb angle correction p=0.76 (53 pts & 3 studies)

T1-S1 Length gain p=0.83 (48 pts & 2 studies)

Dual rods reduced the incidence of rod breakages

No difference in curve correction or T1-S1 length

gain

Sagittal profile and thoracic height

Contrary to commonly held belief, MdGRs do NOT cause hypokyphosis: Mean 4.50 ↑↑ in Thoracic

Kyphosis(n=4 studies)

Pulmonary function

6 patients with EOS-NMD SMA Type II – 2

Neurofibromatosis – 2

William’s syndrome – 1

Cong muscular dystrophy – 1

• Impressive improvement in PFT in patients with SMA-II

• MdGR probably arrest rapid deterioration / decline of PFT and do NOT alter its natural history (γ error!)

USG measurement & Cost-utility analysis

Validated against x-rays: 19 patients

NO Meta-analysis possible

Estimated cost-savings with MdGR in comparison to CGR at Four & Five years (n=2 studies)

Both Studies assume NO MdGR breakage

Conclusion MdGR is a promising novel Rx option

Existing LoE is LOW and WEAK (short follow-up)

Improves pulmonary function in EOS-NMD (γ error!)

Long-term studies with follow-up until graduation from MdGR program are desired

Robust cost-sensitivity analysis studies accounting for rod breakages and complications are needed.

Thank You