constipation after trauma to lower back

[sammybest]

I am 24 yr old male.Few months back i suffered from  a trauma to my lower back, and from the next day i was unable to defecate normally,a small amount of fecal matter passed and then even after applying strain i was unable to pass fecal matter.There was feeling of incomplete evacuation and rectal stasis. I am constipated since then.I get a bowel movement in 3 to 4 days that too in very small amount. It is assosciated with bloating,dyspepsia,acidity,early satiety(unable to eat in normal quantity, after a small anount i get a feeling of fullness) and some pain at the site of trauma.All these symptoms have persisted from the day after trauma.It is not assosciated with any limb weakness or bladder symptoms.I got an x ray spine which was normal,then i got an mri ls spine done, it also didnt show any abnormality,blood inv.-normal,thyroid fn.test- normal. But the symptoms are persisting and its really frustating.I have also lost 3-4 kgs of weight. I have tried laxatives(bisacodyl,polyethylene glycol,lactulose) but was of no use. For dyspepsia and early satiety i took levisulpride,ppi and got little benefit.  All the symptoms had an acute onset after trauma, it has to be of neirological origin.... is it rectal hyposensitivity or any damage to the normal defecation reflex pathway or anything else? Can anyone help what should i do..