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I have read details of your question.It looks that he had excessive injuries.
The sacrum is part of pelvis and pelvic injuries are one of serious injuries. The untable injuries or displaced fracture of sacrum may lead to long term continuous pain.You should ask from treating doctor about type of fracture.A displaced fracture should be operated.It may take at least eight weeks to heal such fracture.The rectal examination in such cases should be done to rule out rectal injuries,although such injuries can be ruled out by history and other investigations.
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