Surgery in sitting position in patient with ventriculoperitoneal shunt in situ may be hazardous!

Abstract

Dear Editor: Complications in sitting position are encountered more often than other surgical positions [1]. Literature search did not reveal any case demonstrating development of an extradural hematoma as a result of surgery in sitting position. We report a case of a 4-year-old female child, weighing 10 kg, admitted in our neurosurgical ward with complaints of headache, vomiting, and difficulty in walking for the last 6 months. A magnetic resonance image scan revealed a contrast enhanced lesion in the pineal region suggestive of pineal tumor. She had earlier undergone endoscopic biopsy removal and a right ventriculoperitoneal shunt surgery. Her medical history was unremarkable, and all preoperative routine investigations were within normal limits. She was scheduled for an elective midline suboccipital craniectomy in sitting position. Following a standard fasting protocol, the child was premedicated with oral atropine 0.4 mg, an hour before surgery. Inside the operation theater routine monitors were attached. General anesthesia was induced with fentanyl 20 mcg and thiopentone 50 mg. To facilitate tracheal intubation with cuffed tube size 5.0, rocuronium 10 mg was administered. Anesthesia was maintained with isoflurane in oxygen and nitrous oxide mixture and intermittent boli of fentanyl 1 mcg/kg and rocuronium 0.1 mg/kg. A double lumen central venous catheter was placed in the right subclavian vein. An arterial line placed in the right dorsalis pedis artery allowed continuous monitoring of blood pressure. The child was placed in sitting position with head supported in a three-pin head rest. A near total excision of the tumor was performed by supracerebellar infratentorial approach. The surgical and anesthetic course lasting approximately 4 h was uneventful. There was no episode of venous air embolism. It was planned to mechanically ventilate the lungs until spontaneous reversal of neuromuscular blockade. The patient was shifted for routine CT scan postoperatively, which revealed a large pneumocephalus (Fig. 1a) along with a high right parietal hematoma measuring 4.8× 1.3 cm (Fig. 1b). However, there was no midline shift and mass effect visible on the scan. A burr hole evacuation of hematoma was performed, and patient was weaned off mechanical ventilation on the second postoperative day. A repeat CT scan revealed resolving pneumocephalus, and no other abnormality. We believe that the ventriculoperitoneal shunt tube in situ may have resulted in such a complication. Excessive drainage of cerebrospinal fluid via the drain could have resulted in intracranial hypotension causing rupture of bridging veins, leading to hematoma formation. H. Prabhakar :G. P. Singh :A. Bindra Department of Neuroanaesthesiology, All India Institute of Medical Sciences, New Delhi, India 110029