Evaluation of trans burr hole ultrasonography usefulness in a resource-limited setting

Purpose: Transcranial ultrasound (US) imaging of intracranial structures is a reliable technique that requires an opening in the skull. In young children the fontanelle serves this purpose, but in adults a postoperative skull defect or some other acquired skull bone defect could be used as potential windows for transcranial US imaging. This study is an audit on the usefulness of the trans burr hole US intracranial imaging technique in a neurosurgical unit in Cameroon (sub-Saharan Africa). Materials and Methods: From January 2001 through December 2004, all files of patients consecutively operated in the neurosurgical unit of the Central Hospital of Yaounde, who underwent an US exploration in the postoperative period through the acquired bone defect or through a skull fracture were reviewed. Transcranial US results were validated by a complementary CT scan or postoperative findings. Results: Seventeen patients were included. Trans burr hole US was effective in diagnosing or in excluding postoperative complications. Hydrocephalus was diagnosed (two cases) or excluded (five cases) after posterior a fossa surgery (five cases) or in case of suspicion of drain dysfunction (two cases). Abscess (one case) or chronic subdural hematoma (two cases) were detected or excluded after cranial surgery for tumours (three cases), aneurysm (one case), compound depressed skull fracture (one case), or intracranial hematoma (three cases). In one case of posttraumatic swelling of the scalp, the US technique revealed an acquired meningoencephalocele. In one case, residual subdural empyema was detected through trans burr hole US. Conclusion: Trans burr hole US technique may be considered in the diagnosis of postoperative complications (abscesses or hematoma) in adults after intracranial surgery or ventriculoperitoneal drain dysfunction especially in resource-limited setting as it is both cheap and widely available.