Handa 9781496386441 Full Sample Chap 1

9

CHAPTER 1  Surgical Anatomy of the Female Pelvis

Other Lumbar Plexus Branches The genitofemoral nerve (L1 and L2) and lateral cutane- ous nerve of the thigh (L2 and L3) can be injured dur- ing gynecologic surgery. The genitofemoral nerve lies on the anterior surface of the psoas muscle ( FIG. 1.9 ), where pressure from a retractor can damage it and lead to anesthesia in the medial thigh and lateral labia. This nerve can also be injured during pelvic lymphadenec- tomy and ureteral reimplantation with psoas hitch. The lateral cutaneous nerve courses over the iliacus muscle and passes under the inguinal ligament just medial to the anterosuperior iliac spine. It can be compressed either by a retractor blade lateral to the psoas or by excessive flexion of the hip in the lithotomy position, causing anes- thesia over the anterior and lateral thigh. Meralgia par- esthetica is a term often used when pain is also present. The largest branch of the lumbar plexus, the femo- ral nerve (L2–L4) can also be injured during gyneco- logic surgery. In the greater (false) pelvis, it emerges from the inferolateral surface of the psoas muscles (see FIG. 1.9 ). It then passes under the inguinal ligament to provide innervation to the anterior thigh compartment muscles and sensation to the anterior thigh and medial leg ( FIG. 1.10 ). Femoral nerve injury during abdominal procedures can result from nerve compression by the

0

5 10cm

Inferior epigastric vessels

Ant. Sup. iliac spine

I

Ilioinguinal n.

Iliohypogastric n. Ant. Inf. iliac spine

Pubic symphysis

The cutaneous sensory innervation of the abdominal wall is derived from the intercostal nerves and the iliohy- pogastric and ilioinguinal nerves. After giving off a lat- eral abdominal cutaneous branch, each intercostal nerve pierces the lateral border of the rectus sheath. There it pro- vides a lateral branch that ends in the rectus muscle. This branch then passes through the muscle and perforates the rectus sheath to supply the subcutaneous tissues and skin as anterior abdominal cutaneous branches. Incisions along the lateral border of the rectus lead to denervation of the muscle, which can render it atrophic and weaken the abdominal wall. Elevation of the rectus sheath off the muscle during the Pfannenstiel incision stretches the perforating nerve, which is sometimes ligated or cauter- ized to provide hemostasis from the accompanying artery. This may leave an area of cutaneous anesthesia. The iliohypogastric and ilioinguinal nerves ( FIG. 1.8 ) pass medial to the anterosuperior iliac spine in the abdominal wall. The former supplies the skin of the suprapubic area. The latter supplies the lower abdomi- nal wall, and by sending a branch through the ingui- nal canal, it supplies the upper portions of the labia majora (anterior labial nerves) and medial portions of the thigh. The ilioinguinal and iliohypogastric nerves can be entrapped or cut during closure of a transverse incision or insertion of accessory trocars in the lower abdomen. This may lead to chronic pain syndromes that may manifest months to years after surgery. The risk of iliohypogastric and ilioinguinal nerve injury can be minimized if lateral trocars are placed superior to the anterosuperior iliac spines and if low transverse fascial incisions are not extended beyond the lateral borders of the rectus muscles. FIGURE 1.8  Nerve and vessel locations on anterior abdominal wall relative to surgically important landmarks. (Redrawn from Rahn DD, Phelan JN, Roshanravan SM, et al. Anterior abdom- inal wall nerve and vessel anatomy: clinical implications for gynecologic surgery. Am J Obstet Gynecol 2010;202(3):234. e1–234.e5. Copyright © 2010 Elsevier. With permission.)

4 5 6

7 8 9 10

External oblique m. Internal oblique m.

3

Transversus abdominis m. Lateral cutaneous n. of the thigh

1

2

Round ligament with ilio-inguinal n. & genital branch of genitofemoral n. (cut) exiting superficial inguinal ring

FIGURE 1.9  Nerves of the lumbar plexus: 1 , sciatic nerve; 2 , femoral nerve; 3 , lateral cutaneous nerve of the thigh; 4 , ilio- inguinal nerve; 5 , iliohypogastric nerve; 6 , subcostal nerve; 7 , sympathetic trunk and ganglion; 8 , genitofemoral nerve; 9 , femoral branch of genitofemoral nerve; and 10 , genital branch of genitofemoral nerve. (Reprinted with permission from Bigeleisen PE, Gofeld M, Orebaugh SL. Ultrasound-guided regional anesthesia and pain medicine , 2nd ed. Philadelphia, PA: Wolters Kluwer, 2015. Figure 35.9.)

Copyright © 2019 Wolters Kluwer, I c. Unauthorized reproduction of the content is p ohibited.

0004290808.INDD 9

4/3/2019 9:29:55 PM