Adolescent Idiopathic Management

Observation

 

Curves < 20o observation only at 3-6 month intervals depending on growth rate 

 

Non Operative Management / Bracing 

 

Never brace curves if patient Risser 4 or 5 

 

Indications

 

1.  Risser 0-2 (growth potential)

 

2.  Curve >30o adolescent

 

3.  Curve >25o with progression (5o in six months)

 

4.  < 10 years old

- very young with high progression potential

- high risk crankshaft if operate

 

5.  Willingness to comply

 

Guidelines

 

Angle                      High Growth Potential                Lowth Growth Potential

<20°                                   observe                               observe or DC

20°-30°                               observe/brace                     observe

30°-45°                    brace                       observe

>45°                                   surgical                              surgical / observe

 

Effect

 

Will control curve only

- end result is initial curve + 5o

 

Brace should be customised to patients curve 

- designed to prevent progression NOT to achieve correction 

- generally see a moderate amount of correction when using the brace

- then slow steady progression of curve back to original magnitude during weaning 

- best curves to brace are those < 40o

 

Bracing complications

 

Failure to prevent progression

Skin irritation

Pressure areas

Abdominal discomfort, eating habit disruption

Cast syndrome - SMA / duodenal obstruction

Psychological

 

Milwaukee Brace  / CTLSO

 

Best for curves with apex above T8 

- three point fixation technique 

- less efficacious for curves > 40o

 

Consists of 

- well moulded pelvic piece above the iliac crests (most important)

- two posterior uprights and one anterior upright 

- neck piece with plastic throat mould anteriorly and two occipital pads posteriorly         

- thoracic pad placed over the apex of convexity of curve 

- lumbar pad over TP between lowest rib and iliac crest on concave side 

- active correction by muscle contraction pulling body away from pads

 

Protocol

 

23 out of 24 hours a day

- result dependant on time in brace

 

Need to check regularly and readjust after 1-2 weeks 

- Xray on 6 month basis 

- if progresses > 45o then surgery

 

Aim for 30-50% correction in first 6 months 

- if not achieved consider surgery 

 

Weaning

 

Once skeletal maturity / Risser 4 / full height 

 

Wean 

- 20 hours for 4 months 

- 16 hours for 4 months 

- 12 hours for 4 months 

- night time only for 4 months 

 

TLSO (Under arm or Boston Brace)

 

If apex < T8 

 

Higher compliance 

May not be as efficacious in holding correction 

Made from cast

 

Operative Management

 

Indications 

 

1.  Immature / Risser 1 /2

- Cobb > 40o with documented progression

- peak height velocity

- will progress 1o per month

- need to stabilise early

 

2.  Mature

- T > 45 - 50o

- TL or L > 30o with marked rotation

- double major > 50o

- significant coronal imbalance

- cosmetic deformity

- failure bracing

 

This curve will progress slowly

- patient has time to make up mind

 

Goals

 

Solid arthrodesis that prevents progression

Balanced spine

Correction of deformity

Prevent respiratory compromise

 

Options

 

1.  Most curves 

- posterior instrumented fusion

 

2.  Lumbar curves

- anterior instrumented fusion

 

3.  Large curves > 70o / young patients

- anterior and posterior surgery

 

Principle

 

Fuse the structural curve with minimum segments

- to stable vertebra

- minimise the levels (preserve motion segments)

- avoid to L5 and above T1 (may increase pain)

- if fuse to L5, only 1 motion segment left, risk LBP

 

Correct curve in sagittal and coronal planes

 

Best to wait til 10 - 12 years to avoid crankshaft

 

Structural Curve

 

1.  Largest curve

2.  One to which trunk shifted

3.  Least correction on AP lateral bending Xray

4.  Pedicles rotated

 

Posterior Instrumented fusion

 

Multisegmental Hook and Pedicle screw systems

- allows for correction via Compression / Rotation / Distraction

 

Crankshaft phenomenon

 

Concept

- seen in young child with high growth potential

- pre PHV surgery or with open triradiates

- pivot on posterior fusion

- vertebral bodies and discs bulge towards convexity

 

Problem

- get loss of correction, increase in rotation, recurrence of rib hump

 

At risk

- Risser 0

- girls < 10

- boys < 13

 

Specific Surgery

 

Lenke Type 1

- main thoracic

- posterior stabilisation

- usually limit to T4 as shoulders equal

 

Scoliosis Fusion Long Thoracic

 

Lenke Type 2

- double thoracic / MT and PT

- need to instrument to T2

- equalise shoulders

 

Scoliosis Fusion Double Thoracic

 

Lenke Type 3

- double major / MT and TL/L

- long posterior instrumented fusion

 

Lenke Type 4

- triple major

- very long posterior instrumented fusion

 

Lenke Type 5

- thoracolumbar / lumbar curve

- can fuse short curve this through bed of T9 / T10 rib

- otherwise posterior instrumented fusion

 

Scoliosis Lumbar Curve Fusion

 

Lenke Type 6

- TL > MT structural

- long posterior instrumented fusion

 

Technique Posterior Instrumented Fusion

 

Pre-operative

 

Consent

Cell saver

- accumulate large blood loss

- often large exposure

Xmatch blood

2 x milled femoral head allograft 

Spinal monitoring / SSEP's

- needles scalp / hands / feet

- begin pre-op once asleep as baseline

IDC

Pedicle screws / TP hooks / rods available

Post op ICU bed especially neuromuscular

 

Position

 

4 Poster Bed

Protect eyes, knees, elbows

No pressure on abdomen / reduce venous bleeding

 

Dissection

 

Posterior approach

- betadine pack buttocks

- midline incision

- divide thoracolumbar fascia midline

- split apophysis with knife (if present)

- subperiosteal elevation strap muscles

- use diathermy, cobb

- sequentially pack with rolled up packs to control bleeding

 

Lumbar spine

- expose facet joints and transverse processes

- don't go between transverse processes laterally as nerve roots here

- pedicle screws inserted bilaterally bottom 3 pedicles

 

Thoracic

- TP hooks above

- pedicle hooks below

- compress

 

2 x rods prebent in sagittal plane

- correct coronal malignement and rotation as able

- may use sublaminar wires if large long curve

- midsection of curve in concavity

- tie over rod and tighten to correct

 

Decorticate lamina, add bone graft along each side

 

Closure

 

Technique Anterior Fusion

 

Indications

 

Large lumbar curve in young patients 

- skeletally immature patient to achieve growth arrest and prevent crankshaft

 

Any lumbar curve to decrease fusion length

- this is debatable

 

Large / rigid curve to achieve mobility 

- severe curves >70o

- supplement posterior fusion

 

Advantages

 

Fewer levels instrumented 

Better correction of rotation

Large surface for fusion

Fusion under compression

Use rib as bone graft

 

Disadvantages 

 

Requires anterior approach

Does not produce lumbar lordosis 

Respiratory problems (need chest drain)

Need to divide segmental vessels

 

Technique

 

Supine, rolled

- curved right sided approach

- remove 9th rib (save for bone graft)

- through bed of rib

- identify peritoneum, stay outside

- take down diaphragmatic crura

- divide segmental vessels, remove discs

- unilateral screws and rod

- repair diaphragm, close over ICC

 

Endoscopic Anterior Instrumentation

 

Advantages

- reduced blood loss and pain

- better scars and cosmesis

 

Disadvantages

- technically difficult

- respiratory problems / deflate lung

 

Growing rods

 

Indications

 

Growing children / open triradiate cartilage

- avoid fusion / crankshaft phenomen

- biannual surgery

- high complication rate 50%

- hook dislocation

- rod breakage

 

Costoplasty / Thoracoplasty

 

Technique

 

Partial excision of 5 or 6 ribs from the TP to posterior axillary line 

 

Advantage

 

Corrects the rib hump 

Cosmetic procedure

Good source of graft 

Does not affect the post op morbidity or pulmonary function

 

Complications G. Coe SRS Report 2006

 

Early

 

Neurological

 

0.32% in posterior corrections (SRS) in adolescents 

- 2% in adults 

- highest in congenital curves

 

Prevention

- SSEP's monitoring in all idiopathic and congenital curves 

- wake - up test in suitable patients (difficult in children)

 

SSEP's

- stimulate in legs, readings in cortex

- avoid inhalation anaesthetics

- time delay as must average amplitudes and reduce background noise

- issue if lose > 50% amplitudes

 

If lose SSEP's

- avoid hypotension

- transfuse Hb if low

- check electrodes

- wake up test

- give steroids

- reverse correction

- remove instrumentation

 

Infection 1.35%

 

Prophylaxis warranted 

Late chronic infection with Proponiobacterium acnes 

 

Respiratory 1.6%

- PTX

- atelectasis

 

PE 0.02%

 

Death 0.03%

 

Ileus - very common

 

Blood Loss 

 

Avoided with

- autologous blood 

- cell savers 

- hypotensive anaesthesia

- autotransfusion

- often blood loss that contributes to neurological compromise 

 

Incorrect fusion levels / wrong level surgery

 

SIADH secretion 

- decrease UO night of surgery

- steady improvement 2-3/7

 

Late

 

Pseudoarthrosis

- 1% overall

- instrument failure 

 

Crank shaft Phenomena 

 

In rapidly growing child after posterior fusion

- spine will rotate as the bodies grow anteriorly

- thus if child with significant growth then add anterior discectomies and fusion

 

Other solutions

- posterior growing rods

- anterior staples / guided growth

 

Sagittal malalignment 

- loss of lumbar lordosis

- flat back / loss of thoracic kyphosis

 

Back Pain 

 

Related to fusion below L4 and loss of lumbar lordosis 

 

Levels and back pain

- L5 - 80%, L4 - 60%

- L3 - 40%, L2 - 20%

 

Late infection - low virulence organism

 

Results

 

Gothenburg Sweden 1968

- 23 year follow-up post fusion with instrumentation

- preop Cobb 62°; postop 33°; last followup 37°

- same series had 127 patient braced

- prebrace 33°, best brace position 30°, last followup 38°