Case Report: Ventriculoperitoneal Shunt Catheter Migration into the Gluteal Muscle.

Background and importance: Ventriculoperitoneal (VP) shunting remains the standard of care for hydrocephalus but is associated with a high rate of complications, including infection and catheter migration. While distal migration into visceral cavities (e.g., bowel, bladder) or via patent congenital defects (e.g., scrotum) is well-documented, migration into somatic musculature is exceptionally rare. We report a novel mechanism where chronic, inadequately treated colonization led to fibrotic fixation and subsequent traumatic migration into the gluteal muscle. Clinical presentation: A 3-year-old boy with Dandy-Walker malformation underwent VP shunting. One month postoperatively, he developed symptoms of shunt infection. Due to family refusal of shunt externalization, he was treated with prolonged courses of intravenous antibiotics (meropenem and linezolid), resulting in symptom resolution but likely persistent colonization. One year later, following a minor trauma, he presented with a painful mass in the left buttock. Imaging revealed the distal catheter had migrated through the pelvic outlet into the gluteus maximus. Laparoscopy confirmed the catheter was encased in a dense fibrous sheath. Cultures grew Staphylococcus epidermidis. The patient underwent hardware removal, external drainage, and subsequent shunt replacement with full recovery. Conclusion: This case illustrates that non-standard management of shunt infections-specifically relying on antibiotics without hardware removal-can lead to chronic biofilm formation and dense intraperitoneal fibrosis. This "tethering effect" transforms the flexible catheter into a rigid tract, predisposing it to mechanical migration into adjacent somatic structures upon trauma. Strict adherence to standardized protocols involving shunt externalization is critical to prevent such rare mechanical sequelae.