Objective:To investigate the occurrence of posttraumatic hydrocephalus (PTH) in severe braininjured patients who underwent decompressive craniectomy (DC) and to discuss the management.Methods:A total of 389 patients suffering from severe head trauma between January 2004 and May 2010 were enrolled in this study.Clinical data were analyzed retrospectively.Of them,149 patients who underwent DC were divided into two groups according to the presence of PTH:hydrocephalus group and nonhydrocephalus group.Clinical factors including preoperative Glasgow Coma Score (GCS),bilateral or unilateral decompression,and duraplasty in DC were assessed by single factor analysis to determine its relationship with the occurrence of PTH.Results:Of the 149 patients undergoing DC,25(16.8％) developed PTH; while 23 developed PTH (9.6％)among the rest 240 patients without DC.Preoperative GCS,bilateral or unilateral decompression,duraplasty in DC were significantly associated with the development of PTH.Ventriculoperitoneal shunt was performed on 23 of 25 patients with PTH after DC.Frontal horn was preferred for the placement of the catheter.Sixteen of them were operated upon via frontal approach and 7 via occipital approach.After shunt surgery,both radiological and clinical improvements were confirmed in 19 patients.Radiological improvement was found in 2 patients.One patient died eventually of severe pneumonia.Shunt-related infection occurred in 1patient,which led to the removal of the catheter.Conclusions:It is demonstrated that the occurrence of PTH is high in patients with large decompressive skull defect.Patients with low GCS and bilateral decompression tend to develop PTH after DC.Duraplasty in DC might facilitate reducing the occurrence of PTH.Patients with PTH concomitant skull defect should be managed deliberately to restore the anatomical and physiological integrity so as to facilitate the neurological resuscitation.