|Year : 2008 | Volume
| Issue : 6 | Page : 844
Anaesthetic Management of Caesarean Section in an Achondroplastic Dwarf
Kirti N Saxena1, Dheeraj Kapoor2, Bharti Taneja3, Lalit Maini4, Shallu Hora5
1 Professor, Department of Anaesthesiology, Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, India
2 Senior resident, Department of Anaesthesiology, Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, India
3 Assistant Professor, Department of Anaesthesiology, Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, India
4 Associate Professor, Department of Orthopaedics, Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, India
5 P.G.Student, Department of Anaesthesiology, Maulana Azad Medical College & Associated Lok Nayak Hospital, New Delhi, India
|Date of Acceptance||29-Sep-2008|
|Date of Web Publication||19-Mar-2010|
Kirti N Saxena
B-302 Gitanjali Apartments, Vikas Marg Extension, New Delhi-110092
Source of Support: None, Conflict of Interest: None
Achondroplasia is the commonest form of dwarfism which results from abnormal cartilage formation at epiphyseal growth plates .It is also known as short-limbed dwarfism. Anaesthetic management of caesarean section in these patients requires a deep understanding of this condition.
A twenty year old parturient with short stature presented to the hospital in early labour. An elective lower segment caesarean section(LSCS) was planned in view of cephalopelvic disproportion. She had papers which suggested that she had been diagnosed as a case of achondroplasia though details were not available. Combined spinal epidural(CSE) anaesthesia was planned in the patient in view of the death of her first baby following caesarean section under general anaesthesia. Repeatedly dry taps were achieved on attempting dural puncture. Dural puncture was abandoned and an 18 G epidural catheter was threaded via the Tuohy needle. Sensory block till T 6 was achieved with 6ml of local anaesthetic solution. The patient was stable during the intraoperative and postoperative period.
Keywords: Achondroplasia, Dwarf, Epidural anaesthesia, Caesarean section
|How to cite this article:|
Saxena KN, Kapoor D, Taneja B, Maini L, Hora S. Anaesthetic Management of Caesarean Section in an Achondroplastic Dwarf. Indian J Anaesth 2008;52:844
|How to cite this URL:|
Saxena KN, Kapoor D, Taneja B, Maini L, Hora S. Anaesthetic Management of Caesarean Section in an Achondroplastic Dwarf. Indian J Anaesth [serial online] 2008 [cited 2020 Jan 27];52:844. Available from: http://www.ijaweb.org/text.asp?2008/52/6/844/60699
| Introduction|| |
Achondroplasia is the commonest form of dwarfism which results from abnormal cartilage formation at epiphyseal growth plates  . It is also known as short-limbed dwarfism. Anaesthetic management of caesarean section in these patients requires a deep understanding of this condition.
| Case report|| |
A twenty year old parturient with short stature presented to the hospital in early labour. She had a term pregnancy and her antenatal course had been uneventful. An elective lower segment caesarean section (LSCS) was planned in view of cephalopelvic disproportion. On preanaesthetic assessment there was no significant past history except that she had undergone a previous LSCS under general anaesthesia two years back and the baby died after birth. However no records were available. The family history revealed that her father and both siblings were short statured. She had papers which suggested that she had been diagnosed as a case of achondroplasia though details were not available.
On examination she was seen to be short statured with a height of 115cm and her weight was 45 kg. She had a large head with frontal bossing, a saddle nose[Figure 1], short neck and short limbs[Figure 2]. Her airway examination placed her in Mallampatti grade II and she had full range of neck movement. Examination of her spine showed mild kyphosis in the lumbar area.
The patient was administered ranitidine (50mg) and metoclopramide (10mg) for aspiration prophylaxis. Her informed consent in view of short stature with kyphoscoliosis was taken. Combined spinal epidural (CSE) anaesthesia was planned in the patient in view of the death of her first baby following caesarean section under general anaesthesia . Equipment for management of difficult intubation was kept to take care of any complications of the procedure. E.C.G , non invasive blood pressure and pulse oximeter monitoring were instituted and she was preloaded with 500 ml of Ringer's lactate solution.
The patient was put in the sitting position for CSE .Using a 17G Tuohy needle, epidural space was identified at L 3 - L 4 ( 3 cm from skin ). A 27 G Whitacre needle was introduced via the Tuohy needle to perform dural puncture however repeatedly dry taps were achieved. After this another attempt at subarachnoid block was made in the L4-L5 space with another 25 G spinal needle keeping the Tuohy needle in place. Again a dry tap was obtained. Dural puncture was abandoned and an 18 G epidural catheter was threaded via the Tuohy needle and fixed at a depth of 7 cm. 2 ml of 2% lidocaine with 1: 200000 adrenaline was given as test dose.The patient was placed supine with a slight head up tilt and a wedge was placed under the right hip.
After waiting for 5 minutes to confirm proper placement of epidural catheter , 4 ml of 2 % lidocaine with 1:200000 adrenaline was given via epidural catheter in graded doses of 2ml. Sensory block till T 6 was achieved. Surgery was commenced and a male infant weighing 2.67kg was delivered after 10 min. The APGAR score was 9 at 1 and 5 minutes and there was no feature suggestive of achondroplasia in the baby.
The patient was stable during the intraoperative period. Post operative analgesia was given by tramadol 25 mg in 6 ml normal saline via the epidural catheter and intramuscular diclofenac 50 mg. The post operative period was uneventful and the mother and baby were discharged after 7 days.
During the postoperative period we decided to investigate the patient. The patient was assessed by an orthopaedic surgeon. who advised certain X-rays to clinch the diagnosis. These revealed an enlarged calvarium with shortening of skull base.The distal end of ulna appeared medially directed (reverse madelung deformity).There was deepened intercondylar notch in distal femur epiphysis and the joint space appeared reduced .There was mild reduction of AP diameter of vertebrae with posterior scalloping and progressive reduction in interpedicular distance along L 1 to L 5 vertebrae. In addition to these there was squaring of iliac wings (tombstone appearance), narrowing of the pelvic cavity, reduced sacrosciatic notch, flattened acetabular roof with shortening of femoral necks. All these features were found to be characteristic of achondroplasia  .
| Discussion|| |
There are greater than hundred different types of dwarfism, many of which have specific implications for the anaesthesiologist. Although each particular disorder is relatively rare, the large number of dwarfs ensures that any practicing anaesthesiologist is likely to encounter these patients  . People with severe short statures can be divided into two categories:
- Midgets ,who have proportionate growth and normal ratio of trunk to limb length.
- Dwarfs, having short stature and disprortionate development characterised either by short limbs, or short trunks.
Achondroplasia (abnormal endochondral bone formation) is the most common type of disproportionate short stature. It is an autosomal dominant genetic condition but 80% of cases result from a spontaneous mutation  . Females are affected more frequently than males. Anaesthesia, whether general or regional poses many potential problems in these patients specially during the later stages of pregnancy. Achondroplastic dwarfs characteristically have low fertility rate and those who do conceive ,often require caesarean section because the normal sized fetal head and smaller than the normal maternal pelvic diameter results in cephalopelvic disproportion during the later stages of pregnancy  . Additionally the fetus may have a narrow foramen magnum and upper cervical spine , creating the potential for spinal cord compression during neck manipulation  .
These patients have several derangements which have potential for complications during administration of anaesthesia. Narrow nasal passages and nasopharynx, large tongue and mandible, short neck, craniofacial abnormalities such as macrocephaly, frontal bossing, depressed nasal bridge, maxillary hypoplasia and occipitalisation of the first cervical vertebra can all lead to difficulty in mask ventilation, glottic opening visualisation and intubation  . Tracheomalacia may also be present. Review of all previous anaesthetic records regarding airway management should be done. Preoperative evaluation of the airway by various radiological investigations like CT scan and MRI is indicated. Awake fiberoptic intubation has been recommended  .
Restrictive lung disease is common in these patients due to thoracic dysplasia(rib hypoplasia), thoracic lordosis and thoracic kyphoscoliosis. There is ventilation perfusion mismatching due to decreased FRC and increased closing volume promoting atelectasis which require thorough evaluation of pulmonary function. In addition to this there is a tendency for sleep apnea which may be central or obstructive in nature due to craniofacial abnormalities and hypotonia of upper airway muscles  . These can lead to development of pulmonary hypertension. Compression of spinal nerve roots can lead to development of neuromuscular weakness. Because of all these problems there may be difficulty in maintaining oxygenation during general anaesthesia and post operative mechanical ventilation may be required .
Spinal cord and nerve root compression syndrome due to prolapse of intervertebral discs into the stenosed spinal canal can lead to slowly progressing paraparesis, quadriparesis, sensory deficits, sphincter deficits, autonomic hyperreflexia  . Suxamethonium should be avoided as it can lead to life threatening hyperkalemia in presence of peripheral denervation There is constriction of the spinal canal resulting in narrowing of subarachnoid and epidural spaces which may cause difficulty in establishment of central neuraxial blockade.
Pregnancy in achondroplastic dwarfs leads to further problems as the uterus remains an entirely intraabdominal organ because there is failure of normal sized fetal head to engage in narrow pelvic inlet  . Thus, diaphragmatic splinting occurs causing further reduction in FRC and there is severe aortocaval compression.
There are several reports of parturients with achondroplasia undergoing caesarean section successfully under both general anaesthesia ,, as well as under central neuraxial blockade however difficult intubation has been encountered , This decision may be guided by various factors such as expected difficulty in airway management, whether caesarean section is emergency or elective in nature, history of previous anaesthesia, history of prior laminectomy and individual variations in the cases. The possibility of atlanto-axial instability, restrictive lung disease and neuromuscular weakness would influence the decision to avoid general anaesthesia. In our patient we avoided giving general anaesthesia because we suspected that the death of her baby could have occurred during the previous caesarean section under general anaesthesia due to presence of pulmonary hypertension in the mother leading to hypoxaemia in the baby. Secondly, the author has successful experience of giving CSE to several short statured parturients with kyphoscoliosis for caesarean section.
Caution has been advised against giving regional anaesthesia as neurological anomalies caused by spinal anomalies may be attributed to it  . Problems may be encountered while giving central neuraxial blockade because of difficulty in identifying the interspinous spaces due to lumbar hyperlordosis, reduced interpedencular distance, osteophytes formations and malformed verterbrae. There may be spinal stenosis making it difficult to perform spinal anaesthesia  . In our patient, repeatedly dry tap was obtained on attempting lumbar puncture. It has been advocated that single shot subarachnoid block should be avoided due to unpredictability of spread  as the spinal cord may end at a lower level  . However spinal anaesthesia has been given successfully without any sequelae in such a patient. Sensory blockade tillT3 was obtained with 1.3 ml of 0.5% hyperbaric bupivacaine given in the sitting position  .
Epidural anaesthesia has been given for caesarean section in several parturients with achondroplasia by several authors, all of whom used an epidural catheter to give graded doses of local anaesthetic ,, . A large variation in the heights of the patients and individual variations would have an effect on the levels achieved. Different volumes of test doses have also been used keeping in mind the short stature of these patients as accidental subarachnoid injection could have lead to a high level of blockade as happened in one of these patients  .Keeping these factors in mind we gave a test dose of 2ml of 2% lidocaine with 1:2,00,000 adrenaline followed by 4ml of the same solution to achieve a level of T6 in our patient.There might still have been need for emergency tracheal intubation in the patient in case of any complication therefore equipment for tackling a difficult airway was kept. No such need has been reported in any of the above mentioned reports and the postoperative period was eneventful. CSE (titrable) is a good option for urgent caesarean section despite the small amount of added time required for this technique. It has been used for myomectomy in such a patient  .
The risk of general anaesthesia versus regional anaesthesia must be considered for each patient as severity of spinal abnormality can vary considerably.The chances of successful epidural anaesthesia in achondroplastic patient will be maximized by careful patient selection and preparation, with discussion of risks and possibility of technical complications, optimal positioning and cautious dose titration.
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[Figure 1], [Figure 2]