Bowel and bladder loss after a lower spine injury (“L5″=lumbar) is generally from damage to Nervi Erigantes, the very last nerve that the spinal cord terminates into. You do not have a vein injury (the blood vessel that carries blood back to the heart). Normally an injury at the L5 level leads to loss of the nerves to L5 and S1 (the foot and buttocks muscles) also. Are these functioning well?
You should have had a decompressive/stabilization surgery to have decompressed the spinal canal at this level. If there is still compression and only 4 months since injury, there still is a reasonable chance of bowel and bladder recovery with decompression. If you have already had a decompression, it is a matter of time to see if these functions will return.
Dr. Corenman
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.