What nerve is responsible for pain in the inguinal region and medial thigh following inguinal hernia repair?

Pain in the Inguinal Region and Medial Thigh Following Inguinal Hernia Repair: Nerve Involvement

The genitofemoral nerve, specifically its genital branch, is primarily responsible for pain in the inguinal region and medial thigh following inguinal hernia repair. 1

Anatomical Basis of Post-Hernia Repair Pain

• The genitofemoral nerve, which divides into genital and femoral branches, is most commonly implicated in chronic pain affecting the inguinal region and medial thigh after hernia repair 1
• The genital branch of the genitofemoral nerve follows a laterocaudal course at the level of the internal inguinal ring and can be entrapped in mesh or scar tissue during hernia repair 2
• The ilioinguinal and iliohypogastric nerves may also contribute to post-hernia repair pain, but typically with different pain distribution patterns 2

Nerve Identification and Anatomical Landmarks

• The ilioinguinal nerve typically runs ventrally and parallel to the spermatic cord, dorsally from the aponeurosis of the external oblique muscle 2
• The iliohypogastric nerve runs approximately horizontally and ventrally to the internal oblique muscle, perforating the external oblique aponeurosis at a mean of 3.8 cm cranially from the external ring 2
• The genital branch of the genitofemoral nerve is more difficult to identify but follows a laterocaudal course at the level of the internal inguinal ring 2

Clinical Presentation of Nerve Injury

• Patients with genitofemoral nerve injury typically present with radiating neuropathic pain in the groin, medial thigh, and genitalia 3
• Pain onset commonly follows abdominal surgery, particularly hernia repair, and may be immediate in approximately 67% of cases 3
• Chronic pain after inguinal hernia repair affects approximately 10% of patients and can be quite frustrating for both surgeons and patients 4

Diagnostic Approach

• Selective nerve blocks can help determine which nerve is implicated in the pain syndrome, with a positive response supporting the diagnosis 3, 5
• When post-herniorrhaphy pain symptoms include mostly testicular pain, the genital branch of the genitofemoral nerve is the primary suspect 1
• Physical examination may reveal tenderness along the course of the affected nerve and pain exacerbated by activities that increase intra-abdominal pressure 6

Management Options

• Ilioinguinal/iliohypogastric nerve blocks using local anesthetic and corticosteroids can be effective in treating chronic inguinal pain following groin surgery 5
• For persistent pain, selective neurectomy may be considered, with complete or partial pain relief achieved in approximately 67% of patients 3
• When the genital branch of the genitofemoral nerve is implicated, a specific surgical approach targeting the proximal inguinal canal can be effective 1

Preventive Measures During Hernia Repair

• Proper handling of inguinal nerves during hernia surgery using microsurgical concepts can decrease the incidence of post-operative chronic pain 4
• Meticulous placement of mesh and active revision of surrounding structures and nerve position before closure are essential preventive measures 4
• Understanding the proper surgical anatomy and identification zones for all three inguinal nerves (ilioinguinal, iliohypogastric, and genitofemoral) is crucial for nerve preservation during surgery 2

Complications and Pitfalls

• Despite successful neurectomy, pain recurrence is reported in up to 68% of patients during long-term follow-up 3
• Nerve blocks may not provide permanent relief, necessitating more invasive procedures such as neurectomy in some cases 5
• Delayed treatment of chronic post-hernia repair pain can lead to significant morbidity and decreased quality of life 6