My understanding is that first rib resection is essential for full decompression of the brachial plexus. There are three areas that can compress the plexus. The scaleni muscles are only one of the three. The most common area is between the clavicle and first rib. You are correct that this surgery takes some time to recover. Just make sure that you select a meticulous surgeon who has great experience.
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.