Having communicated with a great deal of athletes who have suffered from sports hernia after discussing my trials with the injury, it’s not uncommon to see a fairly high rate of relapse. Surgery appears to be a better route than conservative management if a sports hernia is an accurate diagnosis (Caudill, 2008), however, the results are not outstanding and many often maintain their pain after treatment. In response, physicians identify genitofemoral and ilioinguinal nerve (among others) as pain generators that innervate musculature and play a sensory role at the skin and “clip” them to reduce pain. While sometimes effective, pain can last through this treatment, which is another blog in and of itself.
The ilioinguinal nerve innervates the transverse abdominis, internal oblique, and is invested within the fascia of each. As the ilioinguinal nerve traverses caudally, it enters into a zig-zag pattern and can be impinged upon by tissues near the ASIS and inguinal ligament. Entrapment and dysfunction of the ilioinguinal nerve is then possible (Hammer, 2007; Kopell, 1962).
Evidence is suggestive that the transverse abdominis may reduce tone and contribute less to pelvic stabilization and experience a progressive thinning of the tissue that may be consistent longstanding groin pain cases. Likewise, patients with chronic longstanding groin pain demonstrate altered motor control of the transverse abdominis in ASLR testing (Cowan, 2004). Dysfunctional gait patterns may arise as pelvic stability declines along with a loss of hip extension and internal rotation, which can make the mechanical load on the nerve greater. In an attempt to minimize the stress on the nerve the individual may begin to choose a psychogenic guarding posture that is flexed over in an attempt to limit loading on the abdominal wall (Kopell, 1962).
Dysfunctional stability results in the previously mentioned altered gait patterns presumably as a result that the tissues responsible for exerting a posteriorly directed rotation on the innominate are pushed out of their wheelhouse and the altered “force closure” disturbs gait and mechanical efficiency (Hu, 2010). With altered stability of the pelvis, the hip adductors may begin to experience greater loads eccentrically as they are responsible for balancing the abduction moment after propulsion in running gait (Brukner and Khan, 2008). As you already know, mechanical loading may result in the formation of groin pain generators and local changes in both hard and soft connective tissues so common to runners hernia, osteitis pubis, and other forms of longstanding groin pain.
The question as to what came first, the ilioinguinal nerve entrapment or the initial injury that led to a complex chain reaction of entrapment as a result of scarring and tissue change is up for debate and one that may not be the most effective use of time. It seems that there may be an “interdependence” between the onset of hip OA and ilioinguinal nerve entrapment (Pecina, 2001). What matters most is clearing the road to recovery by manipulating and modifying stress in and on the tissues involved. In the coming weeks I’ll post a few videos of some soft tissue treatment techniques for potentially freeing the ilioinguinal nerve that may be of value.