Mr Shuaib Karmani
Compression of the roots of the sciatic nerve in the lumbar spine causes pain in the lumbar spine extending down the leg below the knee. The patient feels a tightness in the leg and a cramping sensation in the calf and ankle. Sleep can be disturbed and the patient’s leg can be restless. There is paraesthesia and/or numbness in the leg.
If the L5 root is compressed the disturbed sensation affects the shin and dorsum of the foot, particularly the big toe. If the S1 nerve root is effected the disturbed sensation affects the calf and lateral aspect of the foot. Lastly there can be weakness in the leg, this can effect ankle dorsiflexion (L5) and ankle plantarflexion (S1).
In severe cases with a large central disc prolapse, patients can complain of bowel and bladder problems. There can be numbness affecting the perineum. The particular problems with the bladder are insensate incontinence. This is where the patient is not aware of their bladder filling and emptying, and this can also be the case with bowel function. These symptoms suggest cauda equine syndrome and an urgent referral to A+E is needed.