Generally, but not always, the pars defect irritates the L5 nerve roots which causes the tingling. Occasionally, the pars defects grow spurs which can be compressive. As long as the MRI demonstrates no compression of the roots, surgery generally relieves the tingling.
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.