There are several ways to look at this dilemma. On the one hand, because the treatment isn’t all that different for the two problems, a clear and accurate diagnosis may not be necessary. On the other hand, it’s always a good idea to know exactly what you are dealing with — especially if the first phase of treatment (usually conservative, nonoperative care) isn’t successful and surgery is considered.
Both conditions involve impairment of the median nerve somewhere from the elbow down to the wrist. In the case of pronator syndrome (PS), there are multiple different sites where pressure from some of the soft tissues can compress the nerve causing your symptoms. With anterior interroseous nerve (AIN) syndrome, it’s more likely a case of neuritis (inflammation) of the nerve.
The neuritis could be coming from a viral illness, immunizations, strenuous exercise, or pregnancy. The result of AIN syndrome is a motor paralysis or “palsy” of some or all of the muscles innervated by the median nerve. This is a transient neuritis, which means “temporary” — given enough time, the nerve will usually recover.
Both of these conditions are fairly rare, so the information we have on them is limited. The diagnosis requires a careful patient history, physical examination, and electrodiagnostic and imaging studies. Once the diagnosis is made, then the next step is developing an appropriate plan-of-care. Conservative (nonoperative) care is recommended for both conditions. Rest, muscle stretching exercises, activity modification, and antiinflammatory medications are tried for at least six months.
Surgery is only advised when nonsurgical intervention is unsuccessful after many, many months (up to a year or more). The exact surgical approach to take remains a point of considerable debate and discussion for both of these conditions. Although there is no formal evidence-based protocol, most surgeons release the median nerve along its entire course in the forearm for both conditions. Any places of restriction or obstruction are removed.
You may want to direct your question to the surgeon handling your case. There may be specific reasons why additional tests are being recommended. Having an understanding of the whys and wherefores may be important to you whereas other patients don’t really care — they just want the problem gone. Your surgeon will understand your interest and probably appreciate an interested audience!