3. Developmental Disorders

Question 1

how do limb malformations arise

Answer 1

some are genetically determined - AuD

some due to insult to the developing bud usually between 4th and 5h week gestation

Question 2

what is the most common congenital malformation

Answer 2

syndactyly

Question 3

syndactyly

Answer 3

2 digits are fused together

surgical separation required (around age of 3 or 4)

Question 4

polydactyly

Answer 4

extra digit formed

treated by amputating the extra one

Question 5

fibular hemimelia

Answer 5

partial or complete absence of the fibula

leads to a shortened limb, bowing of the tibia and ankle deformity

Question 6

how can fibular hemimelia be treated

Answer 6

mild cases - circular frame external fixator

severe cases - ankle amputation and use of a below knee prosthetic limb

Question 7

what does absence or hypoplasia of radius lead to

Answer 7

underdevelopment of the hand (usually absence of thumb) with marked deformity (radial club hand)

Question 8

how is radial hypoplasia treated

Answer 8

surgical reconstruction with thumb reconstruction from the index finger (pollicisation) and correction of the deformity

Question 9

pollicisation

Answer 9

surgical technique in which a thumb is created from an existing finger

Question 10

tarsal coalition

Answer 10

fusion between two tarsal bones of the foot

may cause painful flat feet later in life

abnormal connection may need surgically divided

Question 11

who does Obstetric Brachial Plexus Palsy most commonly arise in

Answer 11

the incidence during vaginal delivery is around 2 in 1000

large babies (macrosomia in diabetes), twin deliveries and shoulder dystocia (difficult delivery of shoulder)

Question 12

erb’s palsy

Answer 12

injury to C5 and 6 nerve roots results in loss of motor innervation to deltoid, supra and infra spinatus, biceps and brachialis muscles

internal rotation of the humerus

leads to classic waiter’s tip posture

Question 13

how is erb’s palsy treated

Answer 13

physio required to prevent contractures early

good outcome in 60-90% cases

surigcal release of contractures and tendon transfers may be required if no recovery

Question 14

Klumpke’s palsy

Answer 14

rarer than Erb’s

lower brachial plexus injury (C8 and T1 roots) caused by forceful abduction of the arm

damage of C8 and T1 leads to combination of radial and ulnar injury which may produce claw hand due to loss of lumbrical function

arm is held in adduction

eg trying to break a fall by grabbing on to something above

Question 15

what may Klumpke’s palsy result in

Answer 15

• Horner’s syndrome due to disruption of first sympathetic ganglion from T1
  
  • remember sympathetic thoracolumbar outflow
• • ptosis, miosis and anhydrosis

Question 16

miosis

Answer 16

excessive constriction of pupil of one eye

Question 17

ptosis

Answer 17

drooping of one eyelid

Question 18

prognosis in Erbs compared to Klumpkes

Answer 18

better in Erb’s - good outcome 80-90% cases

Klumpke - 50% recovery and no specific treatment