Congenital Upper Limb Anomalies 183fetal exfoliated squamous cells, is sampled (trans-abdominally) from the
amniotic sac surrounding a developing fetus, and the fetal DNA is examined.
This is usually done between the 15th and 20th weeks of pregnancy (and not
earlier) to minimize risk to the developing fetus. The obtained fetal cells are
separated from the amniotic fluid, cultured, fixed, stained, and examined
microscopically for chromosomal abnormalities.
CVS is a procedure wherein a sample of the placental tissue (chorionic
villus) is obtained (in a transcervical or transabdominal manner) and assessed
for chromosomal abnormalities, usually with fluorescent in situ hybridization
(FISH) or PCR. CVS usually takes place at 10–12 weeks’ gestation, earlier
than amniocentesis, and is the preferred technique before 15 weeks (Alfirevic
and von Dadelszen, 2003).
Chorionic villi sampling and amniocentesis have both been linked to
procedure-related miscarriages, with average risks of about 1 in 100
pregnancies and 1 in 200 pregnancies, respectively (Olney et al., 1995;
Mujezinovic and Alfirevic, 2007). Apart from a risk of miscarriage, there is a
risk of infection and amniotic fluid leakage. Leakage of the amniotic fluid can
result in oligohydramnios (low amniotic fluid level), which is associated with
developmental disorders including limb reduction defects (Froster and Baird,
1992).
POSTNATAL DIAGNOSIS
After delivery, the pediatrician may consult a congenital hand surgeon to
confirm the diagnosis and with the family, develop a treatment plan. A
detailed history of the pregnancy and history of any known family members
with congenital anomalies is the first step of the assessment. Since CULA can
be isolated or associated to anomalies of other organ systems, the history plays
an important role in determining whether additional systems need to be
evaluated and additional specialists consulted. The initial evaluation and
examination will likely establish a tentative diagnosis and OMT classification
and indicate whether other tests, e.g., genetic, x-rays, or functional, are needed
to confirm the diagnosis. The precise structural and functional CULA
impairment may require ongoing examinations and investigations as the child
grows. The child at play is an exceptional diagnostic tool. How they use the
affected limb and to what degree the affected structures function can largely be
determined at distance by observing play with random or standardized toys.
With time, handedness will become evident. X-rays are an important tool for