Common Congenital Hand Anomalies Flashcards
Congenital hand anomalies can be classified into seven
categories based on the type of embryologic failure
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Ulnar polydactyly is common in African Americans and
is frequently treated with an in-office ligation procedure
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Patients with camptodactyly or clinodactyly frequently
present with mild deformities and functional deficits
F no functional deficits
If severe enough, constriction ring syndrome can lead to
critical lymphedema or compartment syndrome, requiring
emergent release of the constricting bands
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Pollicization is the preferred treatment for thumb hypoplasia that lacks a stable carpometacarpal joint
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Most common type of hand anomaly
Syndactyly, polydactyly, and camptodactylyarethe most frequently encountered disorders
The most common cause of congenital hand anomaly is inheritance
F 60% of cases occur spontaneously, 20% are inherited, and 20% are secondary to an environmental cause
inheritance patterns
may be either autosomal dominant or recessive only
F congenital hand anomalies also present as part of a sequence or an association.
Example of association
VACTERL association (vertebral abnormalities, anal atresia, cardiac defects, tracheoesophageal fistula, renal agenesis, limb anomalies) seen in patients with radial dysplasia
The cortical control for placing the limb in space and for strong grasping is developed by 2 year
F The cortical control
for placing the limb in space and for strong grasping is developed by 1 year
Prehensile grasp and pinch between the thumb and fingers
continue to become refined up to 3 years of age
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The major goals of surgery
orient the hand in space and
provide adequate prehension
Upper extremity development takes place between the2-4 weeks of intrauterine growth
F Upper extremity development takes place between the fifth and eighth weeks of intrauterine growth
arm bud at approximately 30 days gestation, and by 3 7 days
gestation the hand plate is well developed
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Proximodistal limb growth is controlled by a thickened ridge of
ectodermal tissue known as the apical ectodermal ridge (AER)
T the last axis to develop
The delineation of digital rays and finger separation
occurs through apoptosis of specific portions of the AER at wich time in intrautrine life?
between 4 7
and 53 days
defect in the apical ectodermal ridge can lead to polydactyly or
syndactyly
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The zone of polarizing activity (ZPA) is responsible for dorso ventral growth
F The zone of polarizing activity (ZPA) is responsible for anteroposterior or radio/ulnar growth
It is the first axis to be established with its
orientation predetermined before the start of limb bud growth
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Alterations in the ZPA can lead to the development of syndactyly
F Alterations in the ZPA can lead to the development of a mirror
hand
ulnar dimelia
Experimental transplantation of the ZPA to the radial side of
a developing limb will result in mirror duplication of the ulnar hand,
or ulnar dimelia
the dorsal ectoderm controls the dorsal/
volar characteristics of the limb and is driven by the expression of wingless-type mouse mammary tumor virus
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Disturbances of this axis of development may
lead to palmar duplication syndrome
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SYNDACTYLY is occurs failure of differentiation during
embryogenesis with an incidence of 1 in every 2000 to 3000 births
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Most cases of syndactyly are genetics
most cases are isolated occurrences, 10% to 40% of cases are familial, inherited in an autosomal dominant pattern with variable expressivity
The majority of inherited cases associated with distinct syndromic anomalies or sequences,
such as Apert syndrome or Poland sequence
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Syndactyly may be classified in to»_space;»
complete incomplete
simple complex
complicated
Complicated syndactyly is often seen in association with other
conditions or syndromes such as polydactyly, constriction rings, toe webbing, brachydactyly, spinal deformities, heart disorders, or Apert Syndrome
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In cases of complete syndactyly, patients have a shared fingernail between the digits what is called
known as synonychia
The most common
webspace affected in nonsyndromic syndactyly?
middle/ring
finger webspace (57% of cases) followed by the ring/little finger webspace (27% of cases)
In syndromic cases, the thumb/index finger
and index/middle finger webspaces are more commonly involved
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the release is
timed so that it is done early enough to permit normal growth but late
enough to avoid postoperative complications.
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Surgery before 1 year of
age is associated withhigher ratesof scar contracture and potential anesthetic complications.
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Syndactyly of the border digits
asymmetric growth, flexion contractures, and rotation
deformities
Syndactyly of the border digits should undergo surgery in 6-12 month of age
F between 3 and 6 months of age
around 6 months when the infant is bigger and the anesthetic risk is minimal
Withbilateral involvement, both hands should becorrectedsimultaneously in nonambulatory patients younger than 12 to 14 months.
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Sequential surgery can be performed
within 6 months of each other
F Sequential surgery can be performed
within 3 months of each other
It is ideal to complete the reconstruction before 24 months of age when the patterns of the function of the
digits are established.
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The webspace has a dorsal to volar inclination of 40 to
45 degrees and it is reconstructed with a dorsal skin flap.
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release
often results in a skin deficit requiring skin grafting Why?
circumference of the separated fingers is approximately 22% to
30% greater than the circumference of the conjoined digits
Full-thickness skin grafts are preferable to minimize contracture but should be avoided in the web spaces and overlying PIP joints
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Skin grafts from the
wrist or the forearm
F Skin grafts should be taken from the groin and not from the
wrist or the forearm because these are exposed areas and the scars are aesthetically objectionable
A dorsal rectangular or trapezoidal flap is designed approximately two-thirds the distance between the metacarpal heads and the PIP joints.
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Transposition of pulp flaps described by Buck-Gramcko
is elevated to create the paronychial folds
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When skin grafts are used, compression and immobilization are the rule.
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In young children, the dressing is reinforced with an above-theelbow cast with the elbow flexed at 90 degrees
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The cast is typically removed at 2 to
3 weeks and light dressings can be applied until all wounds are fully closed
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Potential complications
graft loss or web creep (distal
migration of the webspace)
prevention of web space creep
Overcompensation of the
webspace by positioning it more proximally
How you can minimize or avoid the need for a skin graft
recruiting excess dorsal tissue with the design of
a dorsal pentagonal flap. This requires more proximal dorsal hand incisions leading to a more conspicuous scar.9* 16 Defatting of the digits prior to flap closure
Younger patients (3-6 months) have the most digital fat amenable to defatting
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Causes of apert syndrom
disturbance of the cell surface receptor for fibroblastic growth factor
Apert syndrome represents the severe end of the syndactyly spectrum with involvement of bones, joints, tendons, and nerves
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Type of syndactyly in Apert syndrom
Type of syndactyly in Apert syndrom
type 1 obstetrician’s or spade hand, is characterized by a narrow first webspace and
syndactyly of the four fingers without thumb involvement. This is the most common and least severe form.
type2 mitten or spoon hand, have syndactyly of all four
fingers with a simple syndactyly ofthe thumb to the index ray.
type 3 as rosebud or hoof hand,
have a tight osseous or cartilaginous fusion of the thumb, index, long, and ring fingers with conjoined nail plates. The little finger is often spared from an osseous union but is still joined to the other digits by a complete simple syndactyly.
Separation of the digits The staging principle is to separate the thumb and little finger bilaterally in the first stage
T typically around the age of
one when the child starts to use the thumb to provide a tripod pinch
Because of skin shortage, it is not necessary for reasonable function to create a five-digit hand in apart syndrom
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Symbrachydactyly is caused by a disruption in the embryonic formation only
F Symbrachydactyly is caused by a disruption in embryonic formation and differentiation resulting in a hand with shortened or webbed digits, digital nubbins, or absent digits
is more common in males, and is affecting the right extremity in two-thirds of cases
F is more common in males, and is often unilateral, affecting the left extremity in two-thirds of cases
When associated with
Poland syndrome, it more commonly involves the right extremity
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distinguish symbrachydactyly from amniotic band syndrome
. Hands with symbrachydactyly often have small nubbins with
fingernails, whereas with constriction bands the short digits occur as a result of intrauterine amputation and will lack nails.
patients with amniotic band syndrome will not only have a visible band on the hand but also on other locations of the body
The goal of reconstruction should be to improve pinch, grip, and single hand function.
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Surgical intervention is not always entirely straightforward
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Polydactyly, can be (preaxial) with duplication of the thumb, the ulnar hand (postaxial), or the central hand with the involvement of the three central rays
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All thumb poly dactyls are autosomal dominant
F patients who present with a triphalangeal thumb exhibit an autosomal dominant inheritance pattern
Thumb duplication is classified using the Flatt classification system, which sequentially describes the duplication from distal to proximal
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type IV (most common) describes duplication at the level
of the MCP joint
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type VII involves a triphalangeal thumb
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Surgery for preaxial polydactyly is generally performed between
9 and 15 months of age,WHY?
prior to the development of pinch grasp
or progressive deviation of the duplicated thumbs
none of the anatomic components of either duplicates is normal
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Although both the ulnar and radial thumb demonstrate a degree of hypoplasia, the ulnar thumb is usually larger
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The ulnar duplicate is preferentially
preserved, not only because ofits larger size, but also to preserve the
native ulnar collateral ligament, which is essential to providing stability during thumb to index pinch
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flexor and extensor tendons may be split with
eccentric origins
F flexor and extensor tendons may be split with
eccentric insertions
