Five-month-old with myelomeningocele, hydrocephalus, and Chiari II stridor

The dominant problem is progressive hydrocephalus: head circumference has risen 4 cm in 3 weeks, the fontanelle is tense, and there is sunsetting. In a 5-month-old with a myelomeningocele and Chiari II, the first operation should be CSF diversion, usually a ventriculoperitoneal shunt, because ETV success is lower under 6 months and in myelomeningocele, and ETV/CPC has a higher failure rate in this age group. The stridor and apnoea could be due to Chiari II brainstem compression, but they can also improve after shunt placement; therefore I would not decompress the Chiari first unless there is severe, life-threatening brainstem dysfunction with a small fourth ventricle and no hydrocephalus. I would insert a programmable valve if available, set at a medium-high pressure, and use an antibiotic-impregnated catheter. If the unit only has a fixed valve, a medium-pressure valve is reasonable. Postoperatively, monitor for over-drainage, subdural collection, and shunt infection. If stridor persists after shunt and hydrocephalus is controlled, then posterior fossa decompression is the next step.

Shunt infection risk in infants is higher than in adults, often 5–15% in published series, and is increased by young age, myelomeningocele, previous wound leak, and prolonged operative time. I would use strict aseptic technique, a double-glove and full-body drape protocol, antibiotic-impregnated catheters, and a single dose of intravenous cefazolin before incision, redosed for long operations. I would avoid a shunt if there is any active wound infection or CSF leak; in that case, a temporary ventricular reservoir or EVD may be safer. The previous sterile CSF from the wound leak does not prove the current CSF is sterile, so I would send CSF for cell count, glucose, protein, and culture if a reservoir is placed. I would not use prophylactic intrathecal antibiotics routinely. Parents should be taught signs of infection: fever, vomiting, lethargy, redness along the tract, and abdominal pain. If infection occurs, the standard is removal of the shunt, external drainage, and antibiotics before reinsertion.

I would explain that the shunt is likely to control the head size and pressure but does not cure the Chiari II or the myelomeningocele; further surgery is common. In a 5-month-old, shunt revision rates are high, and the lifetime risk of at least one revision is substantial. The immediate goals are to relieve pressure, protect vision and cognition, and allow feeding and development. I would explain that stridor may persist if brainstem compression is established, and that a posterior fossa decompression may be needed later if apnoea or swallowing problems continue despite a working shunt. I would also discuss that the myelomeningocele repair and Chiari II can cause neurogenic bladder and orthopaedic problems, requiring multidisciplinary follow-up. The parents should understand that a shunt is a lifelong commitment, with emergency review for vomiting, lethargy, or headache, and that not operating would risk progressive head growth, apnoea, and visual loss. The conversation should include the alternative of ETV/CPC, with its lower success rate at this age.