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1

Classification of CP

Cerebral palsy can be classified on the basis of physiology (according to the movement disorder), anatomy (according to geographic distribution), or function.

Physiologic classification (Fig. 3.33)

Spastic

Increased muscle tone and hyperreflexia with slow, restricted movements because of simultaneous contraction of agonist and antagonist

Most common and is most amenable to improvement of musculoskeletal function by operative intervention

Athetosis

Constant succession of slow, writhing, involuntary movements

Less common and more difficult to treat

Ataxia

Inability to coordinate muscles for voluntary movement, resulting in unbalanced wide-based gait

Less amenable to orthopaedic treatment

Mixed

Typically involves a combination of spasticity and athetosis with total body involvement

Anatomic classification (see Fig. 3.33):

Hemiplegia

Involves upper and lower extremities on the same side, usually with spasticity

“Handedness” often develops early

All children with hemiplegia are eventually able to walk, regardless of treatment

Diplegia

Lower extremity involved more extensively than upper extremity

Most diplegic patients eventually walk.

IQ may be normal; strabismus is common.

Total involvement (quadriplegia)

Extensive involvement, low IQ, and a high mortality rate

Affected patients usually unable to walk

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General overview of CP

Nonprogressive neuromuscular disorder

Onset before age 2 years

Results from injury to the immature brain

Cause is usually not identifiable but can include:

Prematurity (most common)

Prenatal intrauterine factors

Perinatal infections (TORCH—toxoplasmosis, other infections, rubella, cytomegalovirus infection, and herpes simplex)

Anoxic injuries

Meningitis

This upper motor neuron disease results in a mixture of muscle weakness and spasticity.

Initially the abnormal muscle forces cause dynamic deformity at joints.

Persistent spasticity can lead to contractures, bony deformity, and ultimately joint subluxation/dislocation.

MRI of the brain commonly reveals periventricular leukomalacia.

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Functional Classification of CP

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Key Pearls of orthopedic Assessment

Based on physical examination and thorough birth and developmental history

A patient’s locomotor profile is based on the persistence of primitive reflexes; the presence of two or more usually means the child will not be able to ambulate.

Commonly tested reflexes include the Moro startle reflex (normally disappears by age 6 months) and the parachute reflex (normally disappears by age 12 months).

The ability to sit independently by age 2 years is highly prognostic of ability to walk.

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Review treatments for spasticity

Botulinum toxin

Intramuscular botulinum A toxin can temporarily decrease dynamic spasticity.

Mechanism of action of botulinum toxin is a presynaptic blockade of cholinergic receptors at the neuromuscular junction.

Effectiveness of botulinum toxin is limited to 3 to 6 months; therefore, it is not a permanent cure for spasticity.

It is used to maintain joint motion during rapid growth when a child is too young for surgery.

Dorsal rhizotomy

Selective dorsal root rhizotomy is a neurosurgical procedure designed to decrease lower extremity spasticity.

Includes resection of dorsal rootlets that do not exhibit a myographic or clinical response to stimulation

Performed primarily in ambulatory patients (age 4–8 years) with spastic diplegia to help reduce spasticity and complement orthopaedic management

Requires multilevel laminoplasty, which may lead to late spinal instability and deformity

Contraindicated in patients with athetoid disease and nonambulatory patients with spastic quadriplegia (increased spinal deformities)

Systemic medication

Oral baclofen used as adjunct therapy to control overall tone

Provides decreased tone in all extremities by inhibiting signals through the γ-aminobutyric acid (GABA) pathway

Negative effects include increased somnolence and decreased alertness during the day

Baclofen pump

Surgical implantation of a pump that provides only local delivery of baclofen to an area of the spinal cord

Pump delivers a much lower dose of baclofen.

Pump is then refilled when empty.

No systemic delivery; thus less somnolence

May exacerbate scoliosis progression

Wound problems common in thin children

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Surgical Options for Gait disorder in CP

Evaluation

Findings are usually the impetus for the orthopaedic consultation.

Three-dimensional computerized gait analysis with dynamic electromyography and force-plate studies have allowed a more scientific approach to preoperative decision making and postoperative analysis of the results of surgery for cerebral palsy.

Types

1. Toe-walking—contracted heel cords

Treat with ankle foot orthosis (AFO) if passively correctable

Posterior leaf-spring orthotic used for excessive ankle plantar flexion in swing phase of gate

Surgical treatment includes gastrocnemius recession versus tendo-Achilles lengthening

 

2. Crouched gait

Usually due to hamstring contracture•

Resultant deformity includes hip flexion, knee flexion, ankle equinus

Treated with lengthenings at hip, knee, and ankle.

Caution should be exercised with isolated heel cord lengthening—will worsen crouched gait secondary to worsening hip and knee flexion

3. Stiff knee gait

Common in spastic diplegia with rectus femoris firing out of phase

Treat with transfer of distal rectus tendon to the hamstrings

Treatment

Lengthening of continuously active muscles and transfer of muscles out of phase are often helpful.

Procedures should usually be done at multiple levels to best correct the problem.

In general, surgery is performed at age 4 to 5 years. A few generalized guidelines are given in

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Spine treatment with CP

Evaluation

Scoliosis can be severe, making proper wheelchair sitting difficult.

Risk for scoliosis highest in children with total body involvement (spastic quadriplegia).

Surgical indications include curves greater than 45 to 50 degrees, worsening pelvic obliquity, and wheelchair seating problems.

Scoliosis more likely to progress than in idiopathic scoliosis

1–2 degrees per year starting at age 8–10 years

Bracing is less effective.

Treatment

Treatment is tailored to the needs of the patient and must involve all caregivers.

Small curves with no loss of function or large curves in severely involved patients may necessitate only observation.

Curves in ambulatory patients are treated as idiopathic scoliosis with posterior fusion and instrumentation.

Curves in nonambulatory patients and in patients with pelvic obliquity may necessitate posterior fusion with segmental posterior instrumentation from the upper thoracic spine to the pelvis (Luque-Galveston technique), with or without anterior fusion.

Kyphosis is also common and may necessitate fusion and instrumentation.

It is important to assess nutritional status (albumin level <3.5 g/dL and WBC count <1500 cells/μL) preoperatively and to consider gastrostomy tube placement before spinal surgery if indicated.

Much higher complication rate than with idiopathic scoliosis

Wound infection (3%–5%)

Pulmonary complications

Implant failure

Increased fatality rate (as high as 7% in some series)

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Hip Treatments in CP

Initial treatment is with a soft tissue release (adductor/psoas) plus abduction bracing.

Later, hip subluxation or dislocation may necessitate femoral or acetabular osteotomies (Dega) or both to maintain hip stability.

The goal is to keep the hip reduced.

This entity is characterized by four stages:

Hip at risk: abduction less than 45 degrees, with partial uncovering of the femoral head on radiographs. This situation is the only exception to the general rule of avoiding surgery in patients with cerebral palsy during the first 3 years of life.

Patient may benefit from adductor and psoas release.

Hip subluxation: best treated with adductor tenotomy in children with abduction less than 20 degrees, sometimes with psoas release or recession

Femoral or pelvic osteotomies may be considered in cases of femoral coxa valga and acetabular dysplasia, which is usually lateral and posterior.

Spastic dislocation: patients may benefit from open reduction, femoral shortening, varus derotation osteotomy, Dega osteotomy (Fig. 3.35), triple osteotomy, or Chiari osteotomy.

The type of pelvic osteotomy indicated is best determined in a three-dimensional CT scan, which demonstrates the area of acetabular deficiency (anterior, lateral, or posterior) and the congruency of the joint surfaces.

Addressing both hips can prevent dislocation of opposite hip.

Late dislocations may best be left untreated or treated with a Schanz abduction osteotomy or a modified Girdlestone resection arthroplasty (resection below the lesser trochanter).

Windswept hips: characterized by abduction of one hip and adduction of the contralateral hip

Bilateral femoral osteotomies to achieve a more varus angle can assist in maintaining reduction.

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Foot and ankle abnormalities in CP

Goal of treatment is to obtain a plantigrade, painless, braceable foot.

Equinovalgus foot

Most common in spastic diplegia; also in quadriplegia

Causes

Caused by spastic peroneal muscles, contracted heel cords, and ligamentous laxity

Treatment

Peroneus brevis lengthening is often helpful in correcting moderate valgus angulation. Lateral column-lengthening calcaneal osteotomy is used to correct hindfoot valgus angulation.

Equinovarus foot

Most common in spastic hemiplegia

Causes

Overpull of the posterior or anterior tibialis tendons (or both)

Treatment

Lengthening of the posterior tibialis is rarely sufficient.

Transfers

Likewise, transfer of an entire muscle (posterior or anterior tibialis) is rarely recommended.

Split-muscle transfers are helpful when the affected muscle is spastic during both the stance and swing phases of gait.

Split–posterior tibialis transfer (rerouting half of the tendon dorsally to the peroneus brevis) is used in cases with spasticity of the muscle, flexible varus foot, and weak peroneal muscles.

Complications include decreased foot dorsiflexion.

Split–anterior tibialis transfer (rerouting half of its tendon laterally to the cuboid) is used in patients with spasticity of the muscle and a flexible varus deformity.

Often coupled with Achilles tendon lengthening and posterior tibial tendon intramuscular lengthening (Rancho procedure) to treat the fixed equinus contracture.

Hallux valgus

Treatment includes first metatarsophalangeal (MTP) joint fusion

Recurrence rate unacceptably high, with bunion deformity correction without fusion

Proximal phalanx (Akin) osteotomy

Used for hallux valgus interphalangeus in association with hallux valgus and can be done at same time as first MTP fusion

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Upper Extremity managment in CP

Overview

Treatment divided into procedures to increase hygiene and those to produce better function

Functional procedures indicated for patients with voluntary control and better sensibility

Shoulder contracture

Internal rotation contracture of the glenohumeral joint

Treated with proximal humerus derotational osteotomy

Subscapularis and pectoralis lengthening may be needed in addition to biceps/brachialis lengthening and capsulotomy

Indications include contractures greater than 30 degrees that interfere with hand function.

Elbow contracture

Flexion contracture

Treated with:

Lacertus fibrosis release

Biceps and brachialis lengthening

Brachioradialis origin release

Pronation deformity

Treated with pronator teres release

Caution needed with pronator teres transfer to an anterolateral position—can lead to a supination deformity

Wrist flexion deformity

Wrist typically has flexion and ulnar deviation contracture.

May be treated early with flexor carpi ulnaris (FCU) to extensor carpi radialis brevis (ECRB) tendon transfer or FCU to extensor digitorum communis (EDC) transfer in functional patients with voluntary control

Concomitant proximal row carpectomy may improve wrist position and severe digital finger tightness.

Wrist arthrodesis done for severe deformity or for hygienic procedure

Thumb-in-palm deformity

Flexed thumb prevents grasping and can interfere with hygiene.

Treatment with lengthening of adductor pollicis, first dorsal interosseous, flexor pollicis brevis, and flexor pollicis longus muscles

Combined with first web space Z-plasty and tendon transfer to augment thumb extension and abduction

Finger flexion deformity

Swan-neck deformities can sometimes be corrected with correction of wrist flexion deformity.

Fractional or Z-lengthening of tendon (with or without ulnar motor neurectomy) may improve digital flexor tightness and intrinsic spasticity in the patient with a clenched fist.

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Surgical management of the knee in CP

Evaluation

Usually includes hamstring contractures and decreased ROM

Crouch gait in spastic diplegia patients

Treatment

Hamstring lengthening is often helpful (sometimes increases lumbar lordosis).

To prevent peroneal nerve injury, care must be taken not to overextend the knee in the operating room.

Distal transfer of an out-of-phase rectus femoris muscle to the semitendinosus or gracilis muscle is indicated when there is loss of knee flexion during the swing phase of gait (stiff knee gait).

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