Brown-Séquard syndrome is a group of motor and sensory symptoms that occur when one side of the spinal cord is compressed or damaged. Usually, it's caused by a tumor in the spinal cord, trauma (e.g., gunshot wound or stab wound to the neck or back), or loss of blood to the area.
Less often, infectious or inflammatory diseases such as tuberculosis or multiple sclerosis can cause this problem. Disc herniation as a cause of Brown-Séquard syndrome is very rare. Your husband is only one of 25 cases ever reported.
Predicting the outcome of treatment is difficult given that the number of cases to judge from is so small. As with any spinal cord injury, the earlier the treatment, the better the chances for recovery. With a protruding disc, the surgeon's task is fairly straightforward: remove the disc and stabilize the spinal segment.
Minimally invasive microsurgery may be possible. This procedure prevents damage to the soft tissues (e.g., muscles, ligaments) and speeds up recovery. After the operation, a rigid collar is worn while the bone fusion heals.
Once the operation is complete, the surgeon will be able to give you a report of what was done and what to expect. Even though limited in numbers, results of cases reported in the literature are very favorable.