Saturday, June 3, 2017

Antenatal Diagnosis of Orthopaedic Conditions

Antenatal Diagnosis of Orthopaedic Conditions:

Diagnostic methods to detect foetal malformatiions—due to chromosomal or
environmental defects—detection of neonatal musculoskeletal defects by history taking, Apgar score,
clinical examination and anthropometric measurement.
A foetus grows within the mother’s womb in a definite pattern. Any change in this pattern will lead to
congenital malformation. The change may be due to a change in the uterine environment or due to
chromosomal defect. The limbs start growing from the 5th to 6th week of intrauterine life. Changes which develop prior to this period is due to chromosomal abnormality. The changes which take place after that period are due to environmental defect.
Therefore, to diagnose any congenital malformation in the antenatal period needs a detail maternal
history taking which includes age of the patient, intake of different medicines, presence of diabetes,
suffering of the mother from any infection during pregnancy, any trauma during pregnancy, maternal or foetal problems, if any, in the previous pregnancy. The assessment of foetal growth is done as it happens in three phases—the first 12 weeks of organogenesis, the next phase from 13 to 28 weeks and the third phase from 28 weeks onward upto 40 weeks when the foetus grows upto its fullest development. Various congenital malformations occur due to intake of drugs life thalidomide, as it happened in UK and also from maternal suffering from diabetes or infections like measles. Any defect anticipated from history should be corroborated by foetal diagnostic tests like amniocentesis, ultrasonography and others.
The intake of different medicines which cause foetal malformation are aminopterin, thalidomide
(not used now-a-days), trimethadione, paramethadione and antibiotics like chloramphenicol and
tetracycline. The latter causes retarded skeletal growth, hypoplasia of enamel and pigmentation of teeth.
Various diagnostic methods used to detect intrauterine foetal orthopaedic conditions are:
i. Amniography—to diagnose meningomyelocele
ii. Ultrasonography in the third trimester to diagnose cranial malformations and gestational age
iii. Amniocentesis for cytogenetic studies on foetus
iv. Chorionic venous sampling to detect Down syndrome and the like, and rarely X-ray examination (not
in the first-two trimester) to know about bone dysplasias, skeletal malformation and fractures.
Detection of Musculoskeletal Abnormalities in the Neonatal Period
When an orthopaedic surgeon is asked to examine a newborn baby to detect the presence of any
orthopaedic problem, the methods he should follow are:
1. To obtain a thorough history, which encompasses
i. Antenatal history
ii. Natal history
iii. Neonatal history
iv. Family
v. Post-natal history
2. To find out intrauterine growth retardation.
3. To follow Apgar score for properly assessing the newborn.
4. Thorough examination of the baby.
5. Recording anthropometric measurements of the newborn.
Neonatal History Taking
a. Antenatal history: Should include obstetric history, maternal illness during or before pregnancy,
maternal drug intake during pregnancy, history of diabetes, oligo or polyhydramnios, intranatal
and post-natal history, to know notable intrapartum procedures like breech presentation or forceps
delivery.
Extremes of age during first pregnancy have some adverse effects. Maternal ages below 18
years and above 35 years are often associated with (i) Pre-term babies, (ii) Down syndrome and
(iii) Chromosomal anomalies.
Effects of some of the medicines consumed by the mother during early part of pregnancy have
been emphasised for a long-time, specially their deleterious effects on limb formation. Malformations
have been noted with the ingestion of phenytoin sodium, antimalarials and sodium valproate, the
last named drug is suggestive of producing spina bifida.
Diabetic mothers may have babies with vertebral anomalies, femoral hypoplasia and caudal
regression syndrome.
Increased or decreased quantity of amniotic fluid may produce some defects in the babies like
foetal limb defects and club foot from oligohydramnios; Down syndrome, Klippel Feil syndrome,
acondroplasia, multiple congenital anomalies syndromes and anencephaly from polyhydramnios.
Breech presentation—Many of the neonatal problems are caused by unusual presentation of the
baby at birth. About 3 per cent of babies, who are born by breech presentation have some foetal and
maternal factors as the cause. Orthopaedic problems like congenital dislocation of hip, myotonic
dystrophy, Down syndrome, hydrocephalus are some of the important foetal factors, whereas oligo
or polyhydramnios, uterine abnormalities, abnormal placental implantation, twin pregnancy, low
birth weight of babies are some of the maternal factors found in breech presentation.
The effects of breech on new born causing orthopaedic problems are minor ones like haematoma
over thighs, soft tissue injuries and injuries to sternomastoid to major problems like cranial injury,
Erb’s or Klumpke’s palsy, fracture of long bones, spinal cord injury, congenital talipes equinovarus,
birth asphyxia and many others.
b. In searching for natal, neonatal, post-natal and family history the object will be to find out any
deviation from the normal. In obtaining family history, the most important point is pedigree study,
which may indicate a genetic disorder. An elderly primae may have a risk of delivering a baby with
Down syndrome, as an old father points to achondroplasia or Marfan syndrome. It is very important
to search for a number of siblings and deaths among siblings, abortions, intrauterine deaths, familial
illness like diabetes or infectious diseases like tuberculosis and parental consanguinity as a primary
offender before going for a detailed pedigree study in some relevant cases, where a genetic problem
is found in the family tree.
To Find Any Intrauterine Growth Retardation
When the birth weight is less than the 10th percentile for that particular gestational age, it is due
to intrauterine growth retardation and the babies born may show symmetrical retardation causing hypoplastic babies with diminished head size, shorter length and height but fairly adequate subcutaneous
fat, having increased risk of congenital anomalies. On the contrary an asymmetrically retarded growth
causes hypotrophic baby presenting with disproportionately reduced size with a relatively large sized
head and remarkably reduced subcutaneous fat having post-natal problems of asphyxia, hypoglycaemia,
malnutrition and massive pulmonary haemorrhage.
To Follow Apgar Score for Properly Assessing the Newborn
Virginia Apgar1 in 1953 used this score to systematically assess birth asphyxia. She graded five clinical
features at one minute of birth of the baby with scoring from 0 to 2. Recently the assessment is done upto
20 minutes at intervals of 5 minutes. The parameters taken are heart rate, respiratory effort, muscle tone,
response to catheter in the nostril, and colour of the skin. False positive results are possible in cases of
congenital myopathy or congenital neuropathy or acute cerebral trauma or spinal cord trauma with no
foetal asphyxia and low Apgar. A total score of 10 Apgar indicates best possible condition of the infant.
A score of 0 to 3 points towards immediate resuscitation of the infant.
Thorough Examination of the Baby
Orthopaedic examinations are not too many. But while doing so, any other obvious deformity like cleft lip
or palate is noted and written in the history sheet.
There are some important points followed while examining newborns:
i. The examination is done one hour after feeding
ii. The examination should be done gently, methodically and in the presence of the mother
iii. Those examinations which require quietness of the child are to be done first (e.g. auscultation of
heart and palpation of abdomen).
The orthopaedic surgeons are usually asked by paediatricians to see a newborn after common
life-threatening congenital anomalies like tracheo-oesophageal fistula, diaphragmatic hernia, ductal
dependent congenital heart disease, along with others like retarded mental development and growth,
genital hypoplasia, ear anomalies, neural tube defects like meningocele and encephalocele, renal
agenesis with associated urinary and pulmonary problems, obvious umbilical, gastric and intestinal
problems have been diagnosed by paediatric general surgeon.
Recognition of birth trauma is done carefully and systematically starting from head and neck for the
presence of cephalhaematoma, catput succedaneum, skull fractures, sternomastoid tumour, mandibular
fracture, brachial plexus injury, clavicle, humerus or femur fractures, presence of any petechiae or bruise,
and for any visceral injury in case of severe trauma.
Anthropometric Measurements in the Newborn
Anthropometric measurements in the newborn are done as follows:
i. Birth weight—weight recorded within one hour of birth
ii. Length from crown to heel preferably with the help of an infantometer
iii. Head circumference
iv. Mid arm circumference.
In the second examination, which should be done within 24 hours of birth, and the baby having been
fed one hour before the examination, a paediatric orthopaedic surgeon has to find out neuromuscular
maturity by noting posture—of universal flexion, lack or excess of it; hypertonicity shows excessive
flexion and hypotonicity showing lack of it. Some of the important reflexes are tested then.
Moro’s reflex is tested by raising the head of supine infant and allowing it to drop by 10° on to the
examiner’s supporting hand or alternatively by holding the baby at an angle of 45° from the cot and
then suddenly let the head fall back slightly into the palm. This reflex is not well-demonstrated in premature babies. Positive reflex shows opening of hands, extreme abduction of arms and hyperextension
of spine, followed by anterior flexion and adduction of arm are shown in babies born at or after 32 weeks.
Asymmetrical Moro’s reflex is found in Erb’s palsy, fracture clavicle or humerus and in hemiplegia.
Asymmetric tonic neck reflex: This simple test is done by rotation of the head to one side and
maintaining upto the count of five and doing the same to the opposite side. A position reflex with
extension of the upper limb on the side to which face is rotated with flexion of the arm on the side of
the occiput having less similar participation of the lower limbs are present from 35 weeks onwards.
Exaggerated reflex is a sign of cerebral injury.2 The above two reflexes disappear at 4 to 6 months of age of
the baby but may persist in cerebral palsy.
Search should then be made for Congenital Malformations
The malformations may occur in minor or major forms. Abnormalities in minor form of orthopaedic
interest are comptodactyly of fifth fingers, Potter’s thumb, syndactyly of second and third toes, short
fourth metatarsals, infantile bow leg, spooned nails.
Major malformations of common occurrence are musculoskeletal defects like club coot,
arthrogryposis, Down syndrome, limb reduction defects, CNS defects like anencephaly, spina bifida,
encepalocele, hydrocephaly and microcephaly.
Defects like congenital dislocation of hip or knee, radial club hand, amniotic bands should also be
looked for. Proper clinical examinations are done, if any condition is found.
Final Examination of the Baby at the Time of Discharge from the Hospital
This examination will confirm the presence of any abnormality in the baby or detect any, which has been
missed in the first examination. The treatment, if not advised before, should be given and the follow-up
intervals are informed. CNS abnormalities, if any, are confirmed by re-examination.
References
1. Apgar V. A proposal for new method for evaluation of the newborn infant. Anesth. Analg 1953;32: 260.
2. Kulkarni ML. Manual of Neonatology. Jaypee Brothers Medical Publishers (P) Ltd. New Delhi, 72.