|LETTER TO EDITOR
|Year : 2014 | Volume
| Issue : 3 | Page : 354-355
Split cord malformation and the anaesthesiologist
Prakash K Dubey, Shashi Kant
Department of Anaesthesiology and Critical Care Medicine, Indira Gandhi Institute of Medical Sciences, Patna, Bihar, India
|Date of Web Publication||23-Jun-2014|
Dr. Prakash K Dubey
E3/4, Indira Gandhi Institute of Medical Sciences Campus, Patna - 800 014, Bihar,
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Dubey PK, Kant S. Split cord malformation and the anaesthesiologist. Indian J Anaesth 2014;58:354-5
Occult spinal dysraphism is incomplete fusion of dorsal midline structures during embryogenesis in which the spinal defects are covered by intact skin. Split cord malformation represents this condition and consists of duplicated cord, with or without a septum, arising due to a persistent neuroenteric canal.
An increasing number of paediatric patients are now presenting for surgical correction as the advent of magnetic resonance (MR) imaging has helped in early diagnosis of this condition.  Furthermore, the role of prophylactic surgery before neurological deficits appear is now well-established. 
A 25 kg body weight, 4-year-old female child presented with the complaints of weakness in both legs for 6 months. She had a thoracic scoliosis, confirmed by chest X-ray, which showed a convexity towards the right [Figure 1]a. Her routine haematological investigations were within the normal limits. MR imaging revealed vertebral anomalies (hemi vertebrae, butterfly vertebrae), split cord malformation extending from D 9 to L 1 with bony septum at D 12 -L 1 , tethered spinal cord and syrinx at D 1 -D 8 level [Figure 1]b.
|Figure 1: (a) Chest X-ray (left) showing scoliosis with a thoracic curve of 60° and (b) magnetic resonance scan (right) showing the typical findings of Type II split cord malformation|
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The child was posted for laminectomy along with excision of the bony septum and detethering of the cord under general anaesthesia. After institution of routine monitors in the form of electrocardiography, non-invasive blood pressure, pulse oximeter and capnograph, anaesthesia was induced and patient was intubated, using intravenous fentanyl thiopentone and vecuronium, with an armoured tracheal tube. Temperature monitoring was performed by an oesophageal probe. After positioning the patient in the prone position, anaesthetic maintenance was done with intermittent fentanyl, vecuronium, 1% sevoflurane and 60% nitrous oxide in oxygen along with intermittent positive pressure ventilation. Duration of surgery was 150 min and approximate blood loss was 350 ml that was replaced with one unit of packed cell. Residual neuromuscular blockade was reversed with neostigmine and glycopyrrolate. Postoperative pain was managed with a combination of intravenous paracetamol and tramadol, while the child was nursed in the prone position in order to prevent leakage of cerebrospinal fluid.
Split cord malformation was previously known as diastematomyelia (Greek words; diastema, meaning cleft and myelos, meaning the spinal cord). In the Type I condition, the neural tube splits into two with an intervening fibrocartilaginous or bony septum, which was seen in our patient. In Type II, the neural tube remains a single dural sleeve with a split cord by fibrous elements. Various other associated conditions such as sinus tract, lipoma, dermoid, neurentric cyst, meningocele, or myelomeningocele may also form. 
Although the incidence of occult spinal dysraphism is not exactly known, the average age of presentation of split cord malformation is 4-6.5 years with a female preponderance.  Scoliosis with a thoracic curve of approximately 60° to the left and leg pain in this patient prompted us to order an MR scan, which showed all the typical features of this anomaly. Scoliosis with these features or a rapidly progressive curve point to a possible intraspinal abnormality.  There are case reports of associated systemic anomalies in the gastrointestinal, pulmonary, craniofacial and cardiovascular systems, but these are infrequent. 
Scoliosis may lead to restrictive lung status requiring preoperative optimization of pulmonary function. In significant disease, spirometry, arterial blood gas analysis or antibiotics for purulent sputum may be required. Upper thoracic spinal surgery has a greater impact on postoperative pulmonary function. Proper optimisation preoperatively and good postoperative pain management is vital for preventing pulmonary complications.
Preanaesthetic evaluation of such patients includes proper history with emphasis on pulmonary, cardiac, neurological and urological assessment. Routine strategies for a spinal procedure in the prone position in a paediatric patient should be followed.  These include care of eyes and pressure points, monitoring urine output, temperature regulation, managing excessive blood loss and postoperative airway oedema.
A recent study suggests the use of intraoperative dexmedetomidine as an anaesthetic adjuvant in children between 8 and 12 years of age undergoing surgery for spinal dysraphism.  The advantages include a significant opioid sparing effect, a favourable recovery profile, reduced postoperative pain and emergence agitation without adverse haemodynamic effects.
Monitoring of spinal cord function has become the standard of care in spinal surgeries.  This requires avoiding neuromuscular block and halogenated agents and using total intravenous anaesthesia with propofol and a short acting opioid. However, facilities for this monitoring were not available in our institution.
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