Hi,
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It sounds like your friend is bothered by the persistent tingling and numbness in his left foot. I understand these sensations can be quite irritating, especially if your work involves standing for long periods. Did he have these tingling sensations in the same areas before the surgery? If so, have these worsened after the surgery or remained the same? I assume his symptoms before the surgery were also on the left side and his hemilaminectomy was also performed on the left side. It will be nice if I could see the preoperative MRI images to see what the hemilaminectomy was done for. Often, if the surgery involves removal of a large herniated disc or the space available for the nerve is very less (stenosis), then the nerve may get bruised during surgery due to retraction. This means that, in order to decompress the nerve, the surgeon has to retract the nerve to go around the nerve and remove the compressing elements. If the compression is severe, the nerve gets bruised easily and there may be persistent numbness and tingling in the areas of the leg and foot that are geographically supplied by that nerve. Since the surgeon has advised him to wait it out, I assume this is likely the case. Swelling of the foot is common if the nerve supplying that area is not fully functional. The weak muscles in the leg and foot are not able to push the blood back up towards the heart and gravity causes this dependent area to swell up. This is often seen at the end of the day and gets better at night when he sleeps.
It is difficult to predict how long the tingling will last. It could be a few months. The fact that there is tingling and not pure numbness is actually encouraging, although it is more irritating to the patient. If it were a complete nerve injury, then only numbness would be experienced. The presence of tingling means that the nerve is just irritated, inflamed and swollen due to the bruising. If the tingling is very bothersome, he may try some neuralgic pain medications like Gabapentin or Pregabalin. Nonsteroidal anti-inflammatory medications (NSAIDs) may also help in this situation. There is a very rare possibility of other complications like recurrent disc herniation, other post-surgical changes irritating the nerve, etc. These are difficult to diagnose and usually need a new MRI with contrast. However, it is advisable to delay such investigation for at least for two to three months after surgery, since the MRI images at this stage will be obscured by the post surgical changes. If the symptoms of tingling and numbness are progressively worsening and if he develops back pain, a new MRI may be needed irrespective of the time since surgery to rule out infection or instability.