Anesthesia for a patient of acromesomelic dysplasia with associated hydrocephalus, Arnold Chiari malformation and syringomyelia
A 10-year-old male patient (30 kg, 122 cm) presented with short stature and a stooping posture due to pronounced kyphoscoliosis [] along with back pain for the past three years. History of snoring, breath holding, cyanosis, paradoxical chest movement, restless sleep, daytime somnolence and family history of dwarfism were absent. He was cooperative, had normal mental function and intellectual development without any neurological deficit. Airway examination revealed adequate mouth opening, Mallampati class-II and unrestricted neck extension.\nPulmonary functional tests and laboratory values were within regular limits. Chest and cervical region X-ray appeared normal, without subluxation on flexion and extension. Thoracic kyphosis was present with a Cobb's angle of 35° []. Magnetic resonance imaging of brain revealed hydrocephalus, ventriculomegaly, a short posterior fossa, tonsillar herniation and a 3-mm syrinx. Posterior fossa decompression by C1, C2 laminectomy with removal of a foramen magnum rim was planned.\nOn the night before surgery the patient was instructed to follow standard ASA fasting guidelines. Anticipating difficult venous cannulation due to the coarse and loose skin [], the AV300 Vein Viewing System was used to identify a vein in the dorsum of the left hand, which was marked.\nOn the day of surgery, the patient was brought to the operation theatre in a calm state and 5-lead ECG, non-invasive blood pressure and pulse oximetry were connected. A 20-G intravenous cannula was inserted into the previously marked site after application of EMLA cream.\nThe severe kyphoscoliosis and gibbus deformity prevented the patient from assuming a supine position for intubation []. We modified the position by placing a thick pillow that supported the occiput and compensated the gibbus deformity []. Keeping the difficult airway cart ready the child was sedated with intravenous midazolam (1 mg), fentanyl (60 g) and a bolus dose of propofol (60 mg). After confirming the ability to mask ventilate and glottic visualisation following a gentle check laryngoscopy, vecuronium (3 mg) was administered to facilitate intubation. Endotracheal tube size prediction in such patients is difficult.[] Age formula predicted an endotracheal tube size of 6.5 mm, but we could intubate the patient with a 5.5-mm cuffed, flexomettalic endotracheal tube. The operative site being near the brainstem, the left radial artery was cannulated for invasive blood pressure monitoring and an oesophageal temperature probe was inserted. Anesthesia was maintained with an air-oxygen mixture (1:1) and isoflurane, and intermittent boluses of vecuronium and fentanyl as needed.\nAfter preloading with 200 ml of normal saline, the patient was positioned prone on pillows keeping the abdomen free for excursions and the pressure points were padded. Surgery was completed in about 2 h. Postoperatively the patient was turned supine and placed on a thick pillow in a position similar to intubation. The neuromuscular block was antagonised and the trachea was extubated after complete awakening. The patient was shifted to the ICU for monitoring. Injection of paracetamol (500 mg intravenously six-hourly) provided postoperative pain relief. After an uneventful postoperative period, the patient was discharged after 3 days with advice for spinal extension brace, physiotherapy and follow-up.