Pelvic Lymphadenectomy in Gynecologic Oncology-Significance of Anatomical Variations

Abstract

Pelvic lymphadenectomy is a common surgical procedure in gynecologic oncology. Pelvic lymph node dissection is performed for all types of gynecological malignancies to evaluate the extent of a disease and facilitate further treatment planning. Most studies examine the lymphatic spread, the prognostic, and therapeutic significance of the lymph nodes. However, there are very few studies describing the possible surgical approaches and the anatomical variations. Moreover, a correlation between anatomical variations and lymphadenectomy in the pelvic region has never been discussed in medical literature. The present article aims to expand the limited knowledge of the anatomical variations in the pelvis. Anatomical variations of the ureters, pelvic vessels, and nerves and their significance to pelvic lymphadenectomy are summarized, explained, and illustrated. Surgeons should be familiar with pelvic anatomy and its variations to safely perform a pelvic lymphadenectomy. Learning the proper lymphadenectomy technique relating to anatomical landmarks and variations may decrease morbidity and mortality. Furthermore, accurate description and analysis of the majority of pelvic anatomical variations may impact not only gynecological surgery, but also spinal surgery, urology, and orthopedics.

Keywords: anatomical landmarks; anatomical variations; gynecologic oncology; pelvic lymph nodes; pelvic lymphadenectomy.

Figure 6

Anatomical variations of the ureter related to pelvic lymph node dissection in gynecologic oncology (PLNDGO). (A) Duplicated ureter. (A1) complete duplication. (A2) incomplete duplication. (B) Ureteral diverticulum (Adapted from Papin and Eisendrath [29]). (B1) simple diverticulum, (B2) ampullary diverticulum, (B3) diverticulum ending in fibrous prolongation, (B4) multiple diverticulus. (C) Retroiliac ureter. (C1) Behind the common iliac artery, (C2) behind the common iliac vein, (C3) behind the external iliac artery, (C4) behind the external iliac vein, (C5) behind the internal iliac artery.

Figure 1

Common iliac lymph nodes classification (open surgery). 1. Lateral—between lateral part of CIV and medial part of psoas major muscle, 2. medial—medial to CIV and CIA, 3. middle—located in the lumbosacral fossa, 4. subaortic—below aortic bifurcation, 5. promontory—at the promontory. AA—abdominal aorta, IVC—inferior vena cava, RV—right renal vein, PMM—psoas major muscle, CIA—common iliac artery, CIV—common iliac vein, Cr—cranial, Ca—caudal, L—Left, R—right.

Figure 2

External iliac lymph nodes classification (embalmed cadaver). 1. Lateral—lateral to external iliac artery, 2. middle—medial to the EIA and lateral to the EIV, 3. medial—medial to both external iliac vessels, 4. obturator—around the obturator nerve and vessels, 5. interiliac—at the level of CIA bifurcation, between the EIA and IIA. PMM—psoas major muscle, EIA—external iliac artery, EIV—external iliac vein, IIA—internal iliac artery, Ur—ureter, U—uterus, B—bladder, SRA—superior rectal artery, Pr—promontorium, R—rectum, L—left, r—right, Cr—cranial, Ca—caudal.

Figure 3

Internal iliac lymph nodes classification (embalmed cadaver—left hemipelvis). 1. Anterior—anterior to anterior division of internal iliac artery, 2. lateral sacral—close to the paired lateral sacral arteries, 3. gluteal—between superior gluteal and internal iliac artery, 4. sacral (presacral)—along median sacral artery. CIA—common iliac artery, IIA—internal iliac artery, OA—obturator artery, UA—umbilical artery, IPA—internal pudendal artery, IGA—inferior gluteal artery, LSA—lateral sacral artery, ILA—iliolumbar artery, Pr—promontorium, S—sacrum.

Figure 4

Common iliac lymph nodes dissection—anatomic boundaries (open surgery, right side). Dorsal—abdominal aorta bifurcation, ventral—common iliac artery bifurcation, medial—medial aspect of common iliac vessels (on the left side is mesoureter), lateral—psoas major muscle. AAB—abdominal aorta bifurcation, PMM—psoas major muscle, CIAB—common iliac artery bifurcation, M—medial aspect of common iliac vessels on the right side (on the left side is mesoureter), IVC—inferior vena cava, CIA—common iliac artery, CIV—common iliac vein.

Figure 5

External and internal iliac lymph nodes dissection—anatomic boundaries (open surgery left pelvic sidewall). CIAB—common iliac artery bifurcation, ON—obturator nerve, DCIV—deep circumflex iliac vein, GFN—genitofemoral nerve, PMM—psoas major muscle, EIA—external iliac artery, EIV—external iliac vein, OV—obturator vein. The medial border is the ureter dorsally and obliterated umbilical artery ventrally. In the figure, the ureter is stretched medially for better exposure of the visible structures.

Figure 7

The internal iliac artery (IIA) branches. OA—obturator artery, UA—obliterated umbilical artery, SVA—superior vesical artery, UA—uterine artery, VA—vaginal artery, MRA—middle rectal artery, IPA—internal pudendal artery, IGA—inferior gluteal artery, LSA—lateral sacral artery, SGA—superior gluteal artery, ILA—iliolumbar artery.

Figure 8

Morphological variations of the external iliac artery (EIA). (A) The EIA with an inward loop in the left hemipelvis. (B) The EIA with a gentle inward loop in the left hemipelvis. (C) ’S’ shaped EIA in the right hemipelvis. EIA—external iliac artery, EIV—external iliac vein, IIA—internal iliac artery, PMM—psoas major muscle.

Figure 9

An aberrant obturator artery arising as a common trunk with the inferior epigastric artery (open surgery). EIA—external iliac artery, EIV—external iliac vein, AOA—aberrant obturator artery, ACOV—accessory obturator vein, ON—obturator nerve, OV—obturator vein, IEA—inferior epigastric artery, UMA—umbilical artery, FR—the deep femoral ring, OF—obturator foramen. Ca—caudal, Cr—cranial, R—right, L—left.

Figure 10

Classification of IIA variations. Adopted from Adachi [58]. Type I—The superior gluteal artery (SGA) arises separately from internal iliac artery, while the inferior gluteal (IGA) and internal pudendal vessel (IPA) share a common trunk. Type Ia—the bifurcation of IGA and IPA occurs within the pelvis. Type Ib—the bifurcation occurs below the pelvis. Type II—The internal pudendal artery arises separately from the IIA, while the superior gluteal artery shares a trunk with the inferior gluteal artery. Type IIa—the bifurcation of SGA and IGA occurs within the pelvis. Type IIb—the bifurcation occurs below the pelvis. Type III—SGA, IGA, and IPA arise separately from the internal iliac artery, and the internal pudendal artery is the last branch. Type IV—SGA, IGA, and IPA share a common trunk. Type IVA—the SGA is the first vessel from the common trunk, before bifurcating into the other two branches—SGA and IGA. Type IVB—the IPA is the first from the common trunk, which then divides into SGA and IGA. Type V—The IGA has a separate origin from the IIA, while the SGA and IGA share a common trunk.

Figure 11

Uterine artery and umbilical artery, arising in a common trunk. VA arising from the uterine artery. OA—obturator artery, OV—obturator vein, ON—obturator nerve, UMA—obliterated umbilical artery, IIA—internal iliac artery, IGA—inferior gluteal artery, UR—ureter, VA—vaginal artery.

Figure 12

Obturator artery arising from the posterior branch of the IIA. U—uterus, EIA—external iliac artery, EIV—external iliac vein, IIA—internal iliac artery, SGA—superior gluteal artery, LSA—lateral sacral artery, IPA—internal pudendal artery, OA—obturator artery, ON—obturator nerve, SUA—severed uterine artery.

Figure 13

Common iliac vein variations. (A) Incomplete duplication of the CIV; (B) complete duplication of the CIV; (C) lateral duplicated branch drains into the IVC, the medial drain into the CIV. (D) Absent CIV, external and internal iliac veins drain to the contralateral CIV; (E) absent CIV, the EIV drains into the IVC, the IIV drains into the contralateral CIV; (F) Absent CIV, the external and internal veins drain into IVC. Inferior vena cava (IVC), Common iliac vein (CIV), external iliac vein (EIV), internal iliac vein (IIV). (A1,B1,C1,D1,E1,F1) are related to right hemipelvises variations, whereas (A2,B2,C2,D2,E2,F2) are related to left hemipelvises variations.

Figure 14

ILV and ALV anatomy and variations. (A) ILV and ALV anatomy. HV—hemiazygos vein, LV—lumbar veins, ALV—ascending lumbar vein, ILV—iliolumbar vein, IVC—inferior vena cava, LRV—left renal vein, RRV—right renal vein, AV—azygos vein. (B) ILV variations. 1—drains into EIV, 2—drains into the confluence of the CIV, 3—drains into the IIV, 4—two ILVs drains into the CIV. (C) ALV variations. 1—drains into the EIV, 2—drains into the confluence of the CIV, 3—drains into the IIV. (D) Common trunks between ALV and ILV. 1—drains into the EIV, 2—drains into the confluence of CIV, 3—drains into the IIV, 4—drains into the CIV.

Figure 15

ILV or ALV drain into the EIV (open surgery right pelvic sidewall). We can only speculate if these veins are ILV, ALV, or both. (A) Two separate veins drain into the EIV. The EIA is retracted medially. (B) Two veins drain into the EIV via common trunk.

Figure 16

The deep circumflex iliac vein (DCIV) normal anatomy (A) and variation (B) (open surgery, left pelvic sidewall). (A) The DCIV runs over the EIA and drains into the EIV. (B) The DCIV passes under the EIA and drains into the EIV.

Figure 17

IIV variations. (A1) high joining of the IIV to the ipsilateral EIV. (B1) Joining of the IIV to the contralateral CIV. (C1) Separated trunk of the IIV drains into the ipsilateral CIV. (D1) separated trunk of the IIV drains into the contralateral CIV. (E1) Duplication of the IIV. (F1) Duplication of the IIV with a venous connection between them. Variations 1 are related to right pelvic sidewall, whereas variations 2 are related to the left pelvic sidewall.

Figure 18

IIA variations. (G1) Communication vein between the IIV and the EIV. (H1) Separated trunk of bilateral internal iliac veins connecting with each other before draining into the left CIV. (H2) The internal iliac veins form a common trunk, that drains into the inferior vena cava. (H3) The internal iliac veins form a common trunk, which drains into the inferior vena cava, communication vein between the IIVs and ipsilateral EIV. (H4) Both IIVs are joined by a connecting vein that drains into the IVC. (L) Communication veins. (L1,L2) Communication vein between the IIV and ipsilateral CIV. (L3,L4) communication vein between the IIV and contralateral CIV. (L5,L6) Both internal iliac veins are joined with a communication vein, which drains into the inferior vena cava. (L7,L8) Communicating vein between both IIVs. Variations (G1,L1,L3,L5,L7) are related to right pelvic sidewall, whereas variations (G2,L2,L4,L6,L8) are related to left pelvic sidewall.

Figure 19

An aberrant obturator vein (left pelvic sidewall). EIA—external iliac artery, EIV—external iliac vein, PMM—psoas major muscle, AOV—aberrant obturator vein, ON—obturator nerve, OA—obturator artery, DCIV—deep circumflex iliac vein.