A 13-year-old boy comes to the office for a postoperative follow-up visit. He was seen in the emergency department 3 weeks earlier with acute abdominal pain and was found to have acute appendicitis. The patient underwent urgent appendectomy without any apparent immediate complications and was released home. Several days later, he started having burning pain at the surgical scar radiating to the suprapubic region but otherwise feels well. Examination shows a healed surgical incision centered over McBurney point. There is a loss of sensation over the right suprapubic area. The cremasteric reflex is normal. Which of the following nerves is most likely injured in this patient?

Question

A 13-year-old boy comes to the office for a postoperative follow-up visit.  He was seen in the emergency department 3 weeks earlier with acute abdominal pain and was found to have acute appendicitis.  The patient underwent urgent appendectomy without any apparent immediate complications and was released home.  Several days later, he started having burning pain at the surgical scar radiating to the suprapubic region but otherwise feels well.  Examination shows a healed surgical incision centered over McBurney point.  There is a loss of sensation over the right suprapubic area.  The cremasteric reflex is normal.  Which of the following nerves is most likely injured in this patient?

Quizplus · Accepted Answer

Abdominal and pelvic surgery can damage nerves innervating the abdominal wall skin and muscles due to transection from the incision, entrapment from fascia closure, or compression/stretching from tissue retraction or patient positioning. Transection may cause loss of skin sensation or muscle paralysis. Entrapment can cause burning/sharp pain due to continuous stimulation of pain fibers. The iliohypogastric nerve arises from the L1 nerve root, emerges from the lateral border of the upper psoas major, and passes behind the kidney anterior to the quadratus lumborum. The nerve provides motor function to the anterolateral abdominal wall muscles. Its anterior branch emerges above the superficial inguinal ring to innervate the skin above the pubic region; the lateral branch descends over the iliac crest to innervate the gluteal region. Injury to the anterior branch during appendectomy causes decreased sensation at the suprapubic region. (Choice A) The femoral nerve arises from the L2-L4 nerve roots. It provides sensation to the upper thigh and inner leg and innervates muscles that extend the knee. (Choice B) The genitofemoral nerve arises from the L1-L2 nerve roots and provides sensation to the upper anterior thigh and motor function to parts of the genitalia (eg, cremasteric reflex in men, mons pubis in women). (Choice D) The ilioinguinal nerve originates from the L1 nerve root and accompanies the spermatic cord through the superficial inguinal ring. It provides sensation to the upper and medial thigh and parts of the external genitalia. (Choice E) The lateral femoral cutaneous nerve arises from the L2-L3 nerve roots and provides sensation to the skin on the lateral thigh. (Choice F) The obturator nerve arises from the L2-L4 nerve roots. It innervates the skin of the medial thigh and provides motor function for the adductor muscles of the lower extremity. Educational objective: The iliohypogastric nerve provides sensation to the suprapubic and gluteal regions and motor function to the anterolateral abdominal wall muscles. Abdominal surgery (eg, appendectomy) can damage the nerve and cause decreased sensation and/or burning pain at the suprapubic region. __________ References: Abdominal wall paresis as a complication of laparoscopic surgery. (http://www.ncbi.nlm.nih.gov/pubmed/19212701) Anatomy of the ilioinguinal and iliohypogastric nerves with observations of their spinal nerve contributions. (http://www.ncbi.nlm.nih.gov/pubmed/21509811)

A 13-Year-Old Boy Comes to the Office for a Postoperative