Workshop on Surgical Anatomy of the Pelvis and Procedures in Patients with Chronic Pelvic Pain CADAVER COURSE OUTLINE

Transcription

1 Workshop on Surgical Anatomy of the Pelvis and Procedures in Patients with Chronic Pelvic Pain CADAVER COURSE OUTLINE

2 Table of Contents Anterior Abdominal Wall... 6 Female Reproductive Anatomy... 7 UTERUS & LIGAMENTS OF THE PELVIS... 7 OVARIES... 8 FALLOPIAN TUBES... 9 Internal Ring of the Inguinal Canal... 9 INFUNDIBULOPELVIC LIGAMENT CARDINAL LIGAMENT UTEROSACRAL LIGAMENTS (aka rectouterine ligaments) Suspending the Ovaries Appendectomy Retroperitoneum PERITONEAL AND DIAPHRAGMATIC RESECTION OF ENDOMETRIOSIS The Ureter Retroperitoneal Vessels External Iliac System and Pelvic Nerves Obturator Fossa Avascular Spaces of the Female Pelvis PARARECTAL SPACE PARAVESICAL SPACE SPACE OF RETZIUS (aka PREVESICAL OR RETROPUBIC SPACE). 20 Space of Retzius PRE-SACRAL (RETRORECTAL) SPACE AND SACRAL PROMONTORY Presacral Space

3 Additional Neuropelveology Ischiorectal Fossa DISSECTION INDEX GENERAL INFORMATION ANTERIOR ABDOMINAL WALL INTERNAL RING OF THE INGUINAL CANAL SUSPENDING THE OVARIES PROCEDURE Appendectomy Peritoneal and Diaphragmatic Resection of Endometriosis THE URETER THE RETROPERITONEAL VESSELS EXTERNAL ILIAC SYSTEM AND PELVIC NERVES OBTURATOR FOSSA SPACE OF RETZIUS PRESACRAL SPACE ADDITIONAL NEUROPELVEOLOGY CADAVER COURSE OUTLINE DEVELOPED BY MARK DASSEL, MD Assistant Professor 3

4 Welcome Welcome to the lab portion of the first AAGL pelvic pain course, Workshop on Surgical Anatomy of the Pelvis and Procedures in Patients with Chronic Pelvic Pain. Our goal during this cadaveric dissection is to move systematically through a laparoscopic dissection of the pelvis with specific attention paid to clinical correlates of pelvic pain. Wherever possible, we have tried to point out the anatomic relationships of the pelvis as they relate to pelvic pain syndromes. We have made every effort to expose the learner to the most important portions of laparoscopic anatomy. Other musculoskeletal and nerve landmarks will be stressed during the pelvic trainer and live model portions of the laboratory course. This document has been divided into: CLINICAL NOTES PELVIC PAIN CORRELATES ANATOMIC DESCRIPTIONS DISSECTION INSTRUCTIONS PROCEDURE It is helpful to have exposure to this text prior to setting foot in the cadaver lab to gain the full benefit of the clinical and pain correlates as you dissect. Because we have limited time in the cadaver lab, we recommend concentrating on the anatomic and dissection points primarily. The dissection points are meant to be the instructional points only designed to move the dissection as quickly as possible to the next step. 4

5 DISSECTION General Information: Three to four ports should already be placed in the cadaver at your station with pneumoperitoneum established. A 10mm port is placed in the umbilicus because a 10mm camera will give us superior optics in the cadaver. Note: One big difference between operating in a cadaver versus in a live patient is that the camera cannot be cleaned within the patient by touching the uterus or abdominal wall peritoneum or bowel serosa. This will instead make the camera greasy. This is why simple degreaser soaps can be used to clean the camera tip if dirtied, instead of using defoggers as in the live patient. GENERAL PELVIC ANATOMY WITH THE LAPAROSCOPE Basic Anatomy Abdominal Wall Landmarks: Median umbilical ligament-- the embryonic remnant of the fetal urachus and extends from the bladder to the umbilicus. Medial umbilical ligaments-- the embryonic remnant of the umbilical arteries. These are contiguous with the internal iliac artery system. The empty bladder will always be found medial to these 2 ligaments. Lateral umbilical ligaments- These ligaments contain the deep inferior epigastric vessels. Sometimes they are under-developed and difficult to see. If this is the case, one can follow the round ligament into the pelvic sidewall. Here, the round ligament inserts into the internal ring of the inguinal canal. The deep inferior epigastric artery and vein arise from this structure and run cephalad along the anterior abdominal wall. CLINICAL NOTE Deep inferior epigastric artery and vein- Remember these are branches from the external iliac system and travel from the inguinal canal cephalad along the posterior aspect of the anterior abdominal wall. If injured (most commonly during lateral trocar insertion), they can be repaired using a fascial closure device or Keith needle. 5

6 Anterior Abdominal Wall DISSECTION Note the lateral placement of the trocars. These are placed lateral to the lateral umbilical ligaments and cephalad to the ASIS (Anterior Superior Iliac Spine). Besides preventing deep inferior epigastric injury, we are avoiding the ilioinguinal and iliohypogastric nerves as they course medially and caudal along the abdominal wall. Their course proceeds from between the quadratus lumborum and the iliacus laterally, along the abdominal wall, until they branch to collect sensory information from the superficial tissues of the lower abdomen and inguinal region. PELVIC PAIN CORRELATE Injury to the ilioinguinal and iliohypogastric nerves on the abdominal wall can be caused by placing mm ports (or larger) in these lateral locations. The risk of direct injury is Source: (Holt) 6

7 increased due to a larger port, but the further risk of entrapment is magnified when closing the fascial defect to prevent port site hernia. These sites are commonly injured through the lateral extension of a pfannenstiel incision. The pain is commonly sharp and stabbing or burning. A block at the point of maximal tenderness may be beneficial for diagnosis and treatment. Female Reproductive Anatomy UTERUS & LIGAMENTS OF THE PELVIS BASIC ANATOMY The uterus is the dominant organ in the pelvis, located front and center. It is often blamed for pelvic pain and subsequently removed, however pelvic pain syndromes often do not start with the uterus. The uterus is suspended in the mid pelvis, freely mobile in every direction to allow its enlargement during pregnancy. It is made up of a cervix uteri, lower uterine segment and fundus. The cervix uteri projects into the Source: (The End of the Neutral Pelvis Part 1 The Whole Woman Village Post) apex of the vagina. It is contiguous with the lower uterine segment at the confluence of the vesicovaginal fascia, rectovaginal septum, and uterosacral-cardinal complex. Here the cardinal ligament attaches to the utero-cervical junction at 3 and 9 o clock bilaterally. The uterosacral ligaments support this complex posteriorly, attaching the uterus to the sacrum, their uterine attachments at 5 and 7 o clock. Most of the ligamentous support of the vagina is supplied through the cardinal and uterosacral ligaments (DeLancey Level I support). The round ligament provides very little support to the non-gravid uterus, however acts to stabilize the organ in the gravid state. The round ligaments are located at the mid-fundus bilaterally exiting the uterus at 3 and 9 o clock then coursing toward the internal ring of the inguinal canal on the pelvic sidewalls. The infundibulopelvic ligament/ovarian/utero-ovarian ligament complex represents the most cephalad attachment, coursing from the most cephalad portion of the uterine fundus (just posterior to the insertion of the fallopian tubes) to the pelvic sidewalls bilaterally at the level of the pelvic brim. These ligaments have comparatively less connective tissue and are consist of mainly parietal peritoneum covering the ovarian blood vessels. Similarly, the broad ligament is a large sheet of parietal peritoneum containing very little connective tissue that drapes itself over the anterior and posterior aspect of the uterus connecting to the pelvic sidewall bilaterally. 7

8 PELVIC PAIN CORRELATE Primary pain syndromes associated with the uterus are adenomyosis and primary dysmenorrhea. The uterus is often prematurely removed as a primary treatment for chronic pelvic pain. Often this does nothing to treat underlying symptoms. Perhaps the reason hysterectomy is sometimes associated with overall decreased pain is the association with the onset of menses and exacerbation of pelvic floor muscular dysfunction. CLINICAL NOTE Note the significant mobility of this organ in the normal pelvis, allowing for it to grow times its normal size during pregnancy and tolerate the activity of an unborn fetus. The uterine arteries are tortuous as they leave the internal iliac artery as the first branch of the anterior trunk of the structure. This allows for significant stretching and enlargement to occur as the gravid uterus grows. Similarly, the infundibulopelvic ligament (containing the ovarian vessels) stretches caudad from its origin on the sidewall, so it is easily stretched cephalad to a similar degree during uterine enlargement. OVARIES BASIC ANATOMY The adnexa, which includes the ovaries and fallopian tubes bilaterally are located lateral to the uterus connected by the utero-ovarian ligament (which includes within it the utero-ovarian artery and vein). The ovary is suspended by the uteroovarian ligament medially and the infundibulopelvic (IP) ligament (aka the suspensory ligament of the ovary) laterally. Like the uterus, the ovaries are often surgical victims to misdiagnosed pelvic pain syndromes. Ovarian cysts until they are very large are generally asymptomatic. PELVIC PAIN CORRELATE One of the rare occasions the ovary is directly responsible for pain is when encased within scar tissue, such is often the case with ovarian remnant syndrome, a syndrome that develops after incomplete surgical removal of an ovary where residual ovarian tissue remains. This pain syndrome manifests as mid-cycle pain localized to the side of the pelvis where prior oophorectomy has occurred. Excision often results in resolution of the pain. Large ovarian cysts are also known to cause pain, but are usually not associated with chronic pelvic pain syndromes as they are frequently diagnosed and treated quickly. 8

9 FALLOPIAN TUBES BASIC ANATOMY The origin of the fallopian tube is located cephalad and anterior to the insertion of the uteroovarian vessels, thereby the fallopian tube often obscures the ovaries and associated vessels when looking through the laparoscope from a cephalad position. The fallopian tube has five distinct anatomic components extending from the uterine cavity out: interstitial, isthmic, ampullary, infundibular, and fimbrial portions. PELVIC PAIN CORRELATE There are few pain related indications for salpingectomy alone. One notable exception is the case of ectopic pregnancy or PATS (post-ablative tubal syndrome), a case when a prior tubal ligation and intrauterine scarring as a result of endometrial ablation result in a pocket of shedding endometrium without an outlet, leading to distention and resulting pain. At times hydro- or hematosalpinx may be a source of pain as well. An indirect hernia at the internal ring is rare in women, but can be a cause of pelvic pain. Note that identifying the vessels in this way is a helpful way to make sure the trocars are placed laterally enough during port placement to avoid injury to these structures. Internal Ring of the Inguinal Canal DISSECTION 1. Trace the round ligament laterally from the uterus to the internal ring of the inguinal canal. 2. Use a Maryland dissector to tent the peritoneum and endoshears to snip a 0.5 cm opening. The Maryland dissector works well to hold the peritoneum, and the blunt tipped, locking grasper is an excellent dissector. 3. Identify the insertion of the round ligament and the origin of the deep inferior epigastric vessels. 9

10 INFUNDIBULOPELVIC LIGAMENT BASIC ANATOMY This ligament (aka the suspensory ligament of the ovary) originates from the pelvic sidewall at the entry of the true pelvis. The ureter can be seen crossing into the pelvis at it base just having crossed the bifurcation of the common iliac artery cephalad. It contains the ovarian arteries bilaterally which originate directly from the aorta. The ovarian veins run with the ovarian arteries. On the right, the ovarian vein drains into the vena cava. On the left, the ovarian vein drains into the left renal vein. PELVIC PAIN CORRELATE An anatomic variation of the pelvic venous system occurs when the left renal vein is compressed between the superior mesenteric artery (SMA) and the abdominal aorta, leading to a decreased ability of the renal vein and ovarian vein to empty. This can result in a painful pelvic congestion and renal damage. This is known as Nutcracker Syndrome and can be treated a variety of ways, including transposition of the vessels. If renal dysfunction is seen in the setting of left sided pelvic congestion syndrome, this etiology must be ruled out. CARDINAL LIGAMENT BASIC ANATOMY The cardinal ligament, or Mackenrodt s ligament, is a thick fibrovascular structure extending from the pelvic sidewall bilaterally to the uterocervical junction. It contains the uterine vessels branching from the internal iliac vascular system. It is an extremely important landmark in the pelvis, separating the pararectal and paravesical avascular spaces. UTEROSACRAL LIGAMENTS (aka RECTOUTERINE LIGAMENTS) BASIC ANATOMY The uterosacral ligaments are thick fibrous ligaments attached to the anterior portion of the sacrum and run in an anteromedial direction to the uterosacral complex at the apex of the vagina. 10

11 PELVIC PAIN CORRELATE Endometriotic implants are commonly located at the junction of the uterosacral ligament complex to the base of the vagina at the junction of the uterus and uterine cervix. Historically LUNA (laparoscopic uterosacral nerve ablation) was performed as an attempt to denervate the cervix by transecting the visceral afferents of the inferior hypogastric plexus (nerve fibers that carry pain back to the CNS). The procedure has showed limited success in the pelvic pain population at large. Suspending the Ovaries DISSECTION Here we will use a technique to suspend the ovaries that is often employed when resecting endometriosis from the ovarian fossae: 1. Thread the 2-inch Keith needle with a monofilament suture. Place a Kelly clamp on the end of both sutures to hold them together. 2. Puncture the skin approximately 3 cm caudad and 3 cm lateral to the lateral port site and push it into the abdominal cavity perpendicular to the fascia. 3. Use a Maryland dissector from the ipsilateral port to grasp the needle intra-abdominally. From the contralateral port, use the Aesculap locking grasper to steady the ovary. 4. Pierce the ovary with the Keith needle, then regrasp the needle with the Maryland dissector. 5. Move the Keith needle back out of the abdominal cavity about 1 cm medial from its insertion point. The needle on the outside of the abdomen can be grasped with a Kelly, and cut from the suture. 6. A raytec (or other sort of gauze) is placed between entry and exit sutures on the external abdomen, and the stitches are pulled to the correct tension, kept in place using the Kelly clamp. The ovary is now out of the way of the surgical field! This will give us access to the retroperitoneal structures, as well as the para-rectal spaces bilaterally. Repeated with contralateral ovary. 11

12 Appendectomy PROCEDURE On the right side of the abdomen just above the inlet to the true pelvis, the appendix can be located at the base of the cecum. The appendix is a narrow worm-like structure typically measuring from 4-8 cm and less than 1 cm in width. From a pelvic pain standpoint, it has been shown to contain endometriosis commonly in women with stage 3 and 4 endometriosis. 1. To perform an appendectomy, it is important to examine the surrounding area for adhesive disease and be sure you can fully visualize the base of the appendix. Next, grasp the tip of the appendix using a locking grasper. 2. Use the harmonic scalpel to cut the midpoint of the mesoappendix, then separate the mesoappendix from the appendix to the level of the appendicular insertion into the cecum. 3. Place TWO endoloops at the base of the appendix and firmly deploy. 4. From the base of the appendix, milk the contents distally, then deploy a third endoloop 1 cm distal to the double ligature. 5. Transect the appendix between the ligatures using the harmonic scalpel. 6. Typically, we would then place the appendix in an endobag and remove it from the abdomen, but in the interest of time we will lay it out of the way of the dissection in the upper abdomen. 12

13 Retroperitoneum PROCEDURE PERITONEAL AND DIAPHRAGMATIC RESECTION OF ENDOMETRIOSIS The procedure for removing peritoneum from the sidewall and the diaphragm is similar. If the diaphragm is easily visible, you can elect to dissect here, however resecting a portion on the pelvic sidewall, will augment the dissection, so we recommend practicing this on the pelvic sidewall for now. 1. Use a Maryland dissector to grasp and elevate a portion of peritoneum a few mm from the lesion of interest. 2. Incise this peritoneum making a 5mm cut, trying to only cut the bilayered peritoneum in your grasper. (In the live patient, we usually grasp inferiorly first if possible so that if bleeding occurs it does not obscure borders of the dissection.) 3. Undermine the peritoneum so that only the peritoneum is resected. In a larger specimen, pull the peritoneum medially, and use the endoshears to brush away subcutaneous fat. 4. Once the desired area of dissection is undermined, transect the peritoneum. BASIC ANATOMY Entry into the retroperitoneum should take place at the pelvic brim typically. This is where the ureter can be visualized crossing anteriorly to the bifurcation of the common iliac artery into the external and internal iliac artery. Once the ureter is identified, the path of the ureter can be followed along the pelvic sidewall into the pararectal space at the level of the cardinal ligament. The external iliac artery will be seen coursing anteriorly at the pelvic brim. The ureter will most frequently be lower than the Internal iliac artery on the left (LOWER ON THE LEFT) when coursing caudad on the pelvic sidewall below the pelvic brim. CLINICAL NOTE This anatomy becomes important as there is often superficial endometriosis on the peritoneum overlying the ureter. Being able to open the peritoneum, identify the ureter, then perform ureterolysis is the SINGLE MOST IMPORTANT SKILL TO MASTER IN ADVANCED LAPAROSCOPY and is the doorway to the rest of the avascular spaces in the pelvis. 13

14 The Ureter DISSECTION 1. Grasp and tent the peritoneum overlying the ureter at the pelvic brim with a Maryland dissector from the port contralateral to the side of dissection. Once the peritoneum is tented, use endoshears to make a 3-5 mm nick in the peritoneum. 2. An ipsilateral instrument such as a blunt locking grasper can now be place into the retroperitoneal space and used to undermine the peritoneum overlying the ureter. 3. THE ASSISTANT SURGEON ON THE CONTRALATERAL SIDE GRASPS THE INFERIOR PERITONEAL EDGE WITH A MARYLAND GRASPER PROVIDING MEDIAL TRACTION. THIS TRACTION IS THE MOST IMPORTANT PART OF THIS SUCCESSFUL DISSECTION. The goal is to develop an incision along the pelvic sidewall terminating at the insertion of the uterosacral ligament into the utero-cervical junction on the ipsilateral pelvic sidewall. 4. Undermine the peritoneum a few centimeters at a time, cutting only where the peritoneum is visualized to be thin. (Remember the ureter is intimate with the medial peritoneum that makes up the medial aspect of the broad ligament.) A great way to keep the ureter in view is to dissect only immediately anterior to it. It is a durable structure, and does not commonly bleed unless met with sharp tipped instruments. 5. Continue the dissection until you reach the Tunnel of Wertheim, the ureteric tunnel at the level of the cardinal ligament. The Cardinal ligament is one of the borders of the pararectal space. SURGICAL TIP- In a cadaveric dissection, endoshears work well for the ureteral dissection. In practice, I use an ultrasonic device and blunt tipped atraumatic grasper. Using the ultrasonic device, I can use it as a dissector and cutting instrument, minimizing instrument exchanges. For the purpose of this lab, endoshears can be used to undermine and cut the peritoneum as the dissection continues caudad. 14

15 BASIC ANATOMY The outer layer of the retroperitoneal sidewall includes the peritoneum and the ureter. Traditionally the path of the ureter has been described as coursing along the medial aspect of the broad ligament. When opening the broad ligament from an anterior approach, as is the case in total abdominal hysterectomy, the ureter is found on the medial aspect. From a posterior approach, the ureter will actually be found coursing along the peritoneum which is contiguous with the sidewall peritoneum, and most commonly not interact with the broad ligament. The ureter courses from medial to lateral as it leaves the renal pelvis in its abdominal portion. As it enters the pelvis, at the pelvic brim, it can be seen crossing medially immediately anterior to the branch point of the common iliac artery into the internal iliac and external iliac arteries. From here it courses down the sidewall adhered to the sidewall peritoneum, often lower (more posterior) than the internal iliac artery on the left side of the pelvis (LOWER ON THE LEFT). It gradually moves medially until it enters the tunnel of Wertheim in the cardinal ligament just after crossing the uterine artery posteriorly. (WATER UNDER THE BRIDGE.) Typically, dissection stops at this point as there is a rich plexus of blood vessels here. The ureter at it slower aspect is within 2-3 cm of the cervical vaginal junction. CLINICAL NOTE You will see the uterine artery anteriorly to the ureter crossing mediolaterally just prior to the endpoint of this dissection. WATER UNDER THE BRIDGE. Just lateral to this area is where the surgeon ligates the uterine artery during a type 3 radical hysterectomy. 15

16 Retroperitoneal Vessels DISSECTION 1. You will encounter the internal iliac artery at the pelvic brim near the ureter. This structure can be dissected in a similarly to the dissection of the ureter. The internal iliac vein is typically deep and lateral to the structure. 2. Identify branches of the internal iliac artery. Typical branches of the anterior trunk of the internal iliac artery are the middle rectal artery, uterine artery, vaginal artery, obturator artery and superior vesical artery. The superior vesical artery is the terminal branch and will continue coursing anteriorly until it becomes the occluded medial umbilical ligament (the embryonic remnant of the previously patent umbilical arteries). 3. Identify the origin of the uterine artery. As a general guide, the uterine artery is easily identifiable as it branches medially and it has a tortuous appearance. The vaginal, obturator, and superior vesical arteries are typically caudad to the uterine artery. The middle rectal often branches prior to the origin of the uterine artery but courses posteriorly as would be expected. Expect significant variability among these branches, even among anterior and posterior trunk branches, as some anatomists do not even make the distinction of the 2 trunks due their variability. Note that caudal to the bifurcation of the external iliac artery, the posterior trunk of the internal iliac artery branches and sprouts the iliolumbar, lateral sacral and the superior gluteal arteries. In the interest of time we will not fully dissect out the branches of the posterior trunk. 16 Source: jpg (internal-iliac-arteries-mjw jpg)

17 CLINICAL NOTE If dissection is difficult approaching from the posterior aspect of the pelvis (commonly when faced with an obliterated posterior cul-de-sac in stage 4 endometriosis), the medial umbilical ligament can be visualized and traced posteriorly from the anterior abdominal wall. This will lead to the branch point of the uterine artery. External Iliac System and Pelvic Nerves DISSECTION At this point, we will move cephalad along the sidewall to explore the external iliac system as well as nerves in the anatomic proximity. At the level of the pelvic brim, the common iliac artery can be seen branching anterolaterally. The artery is more prominent than the vein, which is located behind it caudally. 1. Continue the dissection anteriorly along the external iliac artery. 2. Laterally and immediately cephalad to this structure, the belly of the large psoas muscle can be seen. Continue the dissection parallel to this structure. 3. Identify the genitofemoral nerve running directly parallel to this structure along the belly of the psoas. It branches anteriorly into the femoral and genital branches of the genitofemoral nerve. 4. Dissect further cephalad and lateral to the psoas muscle to find the thick femoral nerve. It can be seen coursing parallel to the psoas major (after emerging from it posterolaterally). After it leaves the pelvis, it travels between the psoas major and iliacus just deep to the inguinal ligament to the medial aspect of the thigh. 5. Identify the lateral femoral cutaneous nerve. Sometimes it can be seen just cephalad to this structure and is a generous sized nerve as well, but much smaller than the femoral nerve. It has a highly variable route through the abdomen and pelvis and may or may not be seen in this area. 17

18 CLINICAL NOTE The external iliac artery and vein are the only large vessels in the pelvis that cannot be ligated, otherwise resulting in lack of blood flow to the entire lower extremity. All other large vessels of the pelvis will have collateral flow. PELVIC PAIN CORRELATE Special care should be taken around the nerves of the pelvic sidewall; however, these nerves are more commonly associated with neuropathies that result in sensory or locomotor issues, not pain syndromes. An exception to this is the completely sensory lateral femoral cutaneous nerve in which injury can result in a lateral thigh pain syndrome called meralgia paresthetica. Symptoms can be exacerbated by obesity, pregnancy, and tight clothing, sometimes called skinny jeans syndrome. Certain anatomic variants of the nerve lend to this condition. Obturator Fossa DISSECTION 1. Now we return to the pelvic dissection along the internal iliac system. Enter the obturator fossa by proceeding caudal and lateral to the internal iliac artery. Dissection should be performed carefully at this point using small vertical open and closing movements of the blunt tipped locking grasper. 2. Identify the obturator nerve and artery. Most commonly the obturator artery is a branch of the anterior trunk of the internal iliac artery, but in 20% of cases this originates from the external iliac system. 3. Trace the obturator nerve directly anteriorly to the superior aspect of the obturator foramen, the obturator canal. This is where the obturator artery, vein and nerve exit the pelvis. 4. Follow an imaginary line directly posteriorly, to the ischial spine then Dissect the visceral fat medially from this landmark. 5. Identify the sacrospinous ligament. Directly underlying this ligament is the pudendal nerve. 18

19 Avascular Spaces of the Female Pelvis BASIC ANAMTOMY There are 8 avascular spaces in the female pelvis, the paravesical spaces (bilaterally), pararectal spaces (bilaterally), vesicouterine space, rectovaginal space, retropubic space (space of Retzius), and pre-sacral (retrorectal) space. PARARECTAL SPACE BASIC ANAMTOMY BORDERS ARE THE CARDINAL LIGAMENT ANTERIORLY, THE RECTUM POSTERIORLY, THE UTEROSACRAL LIGAMENT MEDIALLY, AND THE PELVIC SIDEWALL LATERALLY. This space is crucial for the resection of deep pelvic endometriosis involving the rectovaginal septum. Entry into this space will allow access to the pelvic portion of the ureters where they cross posteriorly to the uterine artery (water under the bridge). This space is avascular. Entry into this space comes from performing ureterolysis from a cephalad direction. Once the path of the ureter and the uterine artery are identified in the pararectal space, the uterosacral ligament can be identified and transected to resect deep infiltrating endometriosis nodules in the rectovaginal septum. Care should be taken to transect the uterosacral ligaments at their most anterior point so as not to interfere with the sympathetic and parasympathetic nerve fibers of the inferior hypogastric plexus that innervate the pelvic viscera (ie. bladder, bowel). PARAVESICAL SPACE BASIC ANAMTOMY The bilateral paravesical spaces are contiguous with the space of Retzius, the medial umbilical ligaments being the artificial border between the spaces. The anterior border is the pubic bones and Cooper s ligament. The posterior border is the pubocervical fascia that attaches the Arcus Tendineus Fascia Pelvis (ATFP) to the cervix and vagina. The obturator internus, covering the obturator foramen makes up the lateral border of the space. The obturator canal is at the most superior aspect of this space and contains the obturator nerves, arteries, and veins. 19

20 SPACE OF RETZIUS (aka PREVESICAL OR RETROPUBIC SPACE) BASIC ANAMTOMY The space of Retzius is the avascular space found between the urinary bladder posteriorly and the pubic bone anteriorly, extending cephalad to the umbilicus bordered by the lateral umbilical ligaments (obliterated umbilical arteries). The transversalis fascia under the rectus abdominis makes up the roof. The floor of this space is made up of the urethra, pubourethral ligaments and the UVJ (urethrovesical junction, or bladder neck). Inferiorly the space includes the pubic symphysis, superior pubic rami, intimate with Cooper s ligament. This space is entered laparoscopically by delineating the cephalad portion of the urinary bladder dome (by backfilling the bladder) attached to the anterior abdominal wall transversalis fascia. Once the space is entered the bladder easily peels down from the anterior abdominal wall exposing the loose areolar tissue of the space of which extends down to the bladder neck and urethra. Once in this space, it is important to note several anatomic landmarks. At the most inferior aspect is the pubic symphysis and anterior pubic rami. Cooper s ligament can be seen running on the antero-superior aspect of these bony structures. CLINICAL NOTE During a Burch colposuspension, a procedure used to treat stress urinary incontinence, the paraurethral ligaments on either side of the urethrovesical junction are anchored to Cooper s ligament. A similar procedure, the MMK (Marshall-Marcetti-Krantz colposuspension) anchors the paraurethral ligaments anteriorly to the periosteum of the pubic rami. PELVIC PAIN CORRELATE The MMK procedure is associated with a painful syndrome of the pubic symphysis and anterior pubic rami called osteitis pubis. This is characterized by an inflammation of the periosteum due to shearing forces and manifests as severe tenderness of the pubic symphysis and pubic rami. Steroid injections of the pubic symphysis are a potential treatment. 20

21 Space of Retzius DISSECTION 1. Back-fill the bladder with cc of fluid until the dome of the bladder is visualized at the anterior abdominal wall. Occlude the drainage on the Foley catheter. 2. Use the Maryland dissector to grasp the peritoneum cephalad to the bladder dome, and incise using endoshears. Carry this incision laterally to the lateral umbilical ligaments. 3. This space will then easily separate from the anterior abdominal wall with gentle downward traction of the bladder, and side-by-side motion of a grasper separating the loose areolar tissue all the way to the pubic symphysis. 4. Extend the incision on the anterior abdominal wall as needed for exposure. Identify the pubic symphysis, anterior pubic rami and Cooper s ligament. Inferiorly, note the bladder neck (UVJ), pubourethral ligaments and the anterior border of the bladder. 5. On the pelvic sidewall bilaterally, identify the ATFP (Arcus Tendineus Fascia Pelvis), or the fascia white line is visible. It originates from the inferior aspect of the pubic symphysis and is a thick white fascia line extending to the spine of the ischium. It is the attachment point of the pubocervical fascia bilaterally, which is attached to the anterior aspect of the vagina. PELVIC PAIN CORRELATE The ATFP can be used to anchor the lateral portions of the vagina to the pelvic sidewall during a paravaginal repair. An obturator pain syndrome can develop, as well as significant bleeding if sutures are placed too cephalad along this fascial structure because the obturator canal exits the pelvis at this location, which includes the obturator artery, vein and nerve. Neuropathic pelvic pain involving the pelvis following a paravaginal repair could be a result of an obturator nerve injury. Motor deficits involving adduction of the lower extremities may be associated but is not always. The internal obturator muscles can be noted anterior to the fascia white line. These are often part of a greater pelvic floor tension myalgia syndrome, but can be the primary driver in the case of inflammation resulting from a misplaced TOT midurethral sling for placed to treat stress urinary incontinence. 21

22 CLINICAL NOTE It is important to note that this is the space where midurethral slings are placed. The TVT procedure places a synthetic mesh (or cadaveric) sling at the mid-urethra to restore support to the mid-urethra in order to treat stress urinary incontinence. TVT-O is similarly placed, however the TVT is a midline procedure in which the mesh is angled up and under the pubic symphysis. The TVT-O is placed through the obturator membrane more laterally. PELVIC PAIN CORRELATE Care must be taken to avoid injury to the obturator vessels and nerves that exit the obturator canal at the superior lateral aspect of the obturator internus muscle covering the obturator foramen. Bleeding may occur, but more commonly scar tissue in the area or direct nerve impingement can lead to obturator neuralgia. It is also a concern that the fascial, muscular, and ligamentous connections in the area may be affected causing pelvic myofascial pain. The TVT- O passes through 6 different muscles along its path and has been associated with increased pain complications over conventional TVT. PRE-SACRAL (RETRORECTAL) SPACE AND SACRAL PROMONTORY BASIC ANATOMY The pre-sacral anatomic space is the area of the pelvis immediately beyond the sacral promontory where the sacrum and coccyx form a concave area. A thick periosteum can be identified at the sacral promontory between the common iliac arteries at the bifurcation of the aorta. At the cephalad portion of this dissection is the superior hypogastric plexus. The hypogastric nerve arises from this and joins the inferior hypogastric plexus, which innervates (with sympathetic, parasympathetic, and visceral afferent nerves) the viscera of the lower pelvis including the bowel and bladder. CLINICAL NOTE The mesh of a sacrocolpopexy is attached to the sacral promontory commonly using a permanent suture or tack. 22

23 PELVIC PAIN CORRELATE A neuro-resective procedure called presacral neurectomy involves resection of the nerves of the superior hypogastric plexus in this area specifically the T10-L1 sympathetic nerves on the anterior surface of the sacral bone. Though data has shown some efficacy in pain relief with this procedure, urinary issues such as urinary retention are associated, and pain relief is not typically curative. CLINICAL NOTE The left common iliac vein courses just posterior and caudal to the iliac artery at this point, and special care must be taken not to rupture this fragile structure during presacral neurectomy or when clearing the space for placement of the superior arm of sacrocolpopexy. Presacral Space DISSECTION 1. Reflect the colon to the left side of the cadaver. If needed the epiploica of the bowel may be retracted using a Keith needle and suture just as the ovaries were retracted. 2. Grasp the peritoneum overlying the sacral promontory, and make a small 0.5 cm incision with the endoshears. The peritoneum can then be grasped on both sides of the incision and stretched laterally. Extra space may be developed undermining the peritoneum with small snips with the endoshears if needed. 3. Identify the aorta, common iliac arteries, and the presacral nerve plexus at the sacral promontory. 23

24 Additional Neuropelveology BASIC ANATOMY Dissection of the pelvic sidewall neuroanatomy brings understanding to the location of pelvic nerves and can aid in awareness of the location for these nerves as they interact with surgically relevant pelvic anatomy. Relating the nerves of the pelvic sidewall to their nerve roots adds a conceptual basis to the order and location of these nerves. 1. Iliohypogastric nerve 2. ilioinguinal nerve 3. Femoral nerve 4. Lumbosacral trunk 5. Pudendal nerve to the level of its exit at the obturator canal 6. Levator ani nerve 7. Posterior femoral cutaneous 8. Hypogastric nerve 9. Pelvic splanchnic nerves CLINICAL NOTE The posterior femoral cutaneous nerve innervates the largest area of any sensory cutaneous nerve in the body. It branches into cutaneous, gluteal (inferior cluneal) and perineal branches to communicate sensory information from the back of the thigh to the level off the popliteal fossa, inferior half of the buttock, and the posterior portion of the labia majora. 24

25 DISSECTION 1. Open the peritoneum cephalad from the psoas muscle and the prior identified genitofemoral nerve (roots L1-L2) 2. Gently undermine the peritoneum midway anterior along the pelvic sidewall. Approximately at 2-3 cm length intervals, two small nerves will come into view, they will travel laterally and caudal from their nerve roots. The cephalad nerve is the iliohypogastric nerve (nerve roots T12- L1). It will continue to course along the abdominal wall and provide sensory feedback from the anterior abdominal wall. The more caudal nerve is the ilioinguinal nerve (nerve roots T12-L1) and it will similarly run caudally and anterior to provide sensory input from the inguinal canal, inner thigh, and lower abdomen. 3. Moving caudally review the pathway of the femoral nerve (nerve roots L2-L4) which from the typical laparoscopic view from the umbilicus, will be behind the psoas muscle on the cephalad portion. It is a large nerve and can be viewed by retracting the psoas caudally. 4. Moving further along, review the path of the genitofemoral nerve (nerve roots L1-L2). Now, using anterior posterior traction bluntly 25

26 develop the space between the external iliac vessels and the psoas muscle along its visible length. The assistant will retract the psoas and the external iliac vessels by pushing them cephalad and caudal respectively. 5. At the base of this space (posteriorly), the lumbosacral nerve root can be visualized just caudal to the psoas muscle 6. Keep an eye out for the posterior femoral cutaneous nerve which arises from S1 to S3. This nerve runs laterally to the pudendal nerve and exit the pelvis at the greater sciatic foramen, exiting the pelvis just below the piriformis muscle. 7. Following the lumbosacral nerve will be the largest nerve in the body, the sciatic nerve. 8. The sacrospinous ligament will become visible as this nerve is followed deeper into the dissection laterally. In order to expose the roots of the pudendal and levator ani nerves, sacrifice the sacrospinous ligament. The pudendal nerve will be visualized as the cephalad nerve compared with the levator ani nerve. It can be followed to its exit at the obturator canal. PELVIC PAIN CORRELATES The pudendal nerve carries sensory, motor, and autonomic information from the ano-genital region. It originates from the S2-S3-S4 nerve roots, runs inside of the piriformis muscle. It then runs posterior to the sacrospinous ligament (where its course can be palpated and injected) approximately 1 cm medial to the ischial spine as part of a pudendal nerve block. It then runs anteriorly to the sacrotuberous ligament, which is one of the landmarks for its identification by a transgluteal approach to the nerve. It then enters, and travels through Alcock s canal between the obturator and levator ani muscles into the ischiorectal fossa where it divides to innervate the clitoris, labia, perineum, and anal cutaneous regions. 26

27 Ischiorectal Fossa DISSECTION (This dissection will take place after the completion of the cadaveric dissection from a transgluteal approach.) Source - Anatomy: A Regional Atlas of the Human Body, 4th Edition, by Carmine Clemente,

28 DISSECTION INDEX GENERAL INFORMATION Three to four ports should already be placed in the cadaver at your station with pneumoperitoneum established. A 10mm port is placed in the umbilicus because a 10mm camera will give us superior optics in the cadaver. Note: One big difference between operating in a cadaver versus in a live patient is that the camera cannot be cleaned within the patient by touching the uterus or abdominal wall peritoneum or bowel serosa. This will instead make the camera greasy. This is why simple degreaser soaps can be used to clean the camera tip if dirtied, instead of using defoggers like in the live patient. ANTERIOR ABDOMINAL WALL THE DISSECTION- Note the lateral placement of the trocars. These are placed lateral to the lateral umbilical ligaments and cephalad to the ASIS (Anterior Superior Iliac Spine). Besides preventing deep inferior epigastric injury, we are avoiding the ilioinguinal and iliohypogastric nerves as they course medially and caudal along the abdominal wall. Their course proceeds from between the quadratus lumborum and the iliacus laterally, along the abdominal wall, until they branch to collect sensory information from the superficial tissues of the lower abdomen and inguinal region. 28

29 Source: (Holt) INTERNAL RING OF THE INGUINAL CANAL 1. Trace the round ligament laterally from the uterus to the internal ring of the inguinal canal. 2. Use a Maryland dissector to tent the peritoneum and endoshears to snip a 0.5cm opening. The Maryland dissector works well to hold the peritoneum, and the blunt tipped, locking grasper is an excellent dissector. 29

30 3. Identify the insertion of the round ligament and the origin of the deep inferior epigastric vessels. SUSPENDING THE OVARIES Here we will use a technique to suspend the ovaries that is often employed when resecting endometriosis from the ovarian fossae. 1. Thread the 2-inch Keith needle with a monofilament suture. Place a Kelly clamp on the end of both sutures to hold them together. 2. Puncture the skin approximately 3cm caudad and 3cm lateral to the lateral port site and push it into the abdominal cavity perpendicular to the fascia. 2. Use a Maryland dissector from the ipsilateral port to grasp the needle intra-abdominally. From the contralateral port, use the Aesculap locking grasper to steady the ovary. 3. Pierce the ovary with the Keith needle, then regrasp the needle with the Maryland dissector. 4. Move the Keith needle back out of the abdominal cavity about 1 cm medial from its insertion point. The needle on the outside of the abdomen can be grasped with a Kelly, and cut from the suture. 5. A raytec (or other sort of gauze) is placed between entry and exit sutures on the external abdomen, and the stitches are pulled to the correct tension, kept in place using the Kelly clamp. The ovary is now out of the way of the surgical field! This will give us access to the retroperitoneal structures, as well as the para-rectal spaces bilaterally. Repeated with contralateral ovary. 30

31 PROCEDURE Appendectomy On the right side of the abdomen just above the inlet to the true pelvis, the appendix can be located at the base of the cecum. The appendix is a narrow worm-like structure typically measuring from 4-8cm and less than 1cm in width. From a pelvic pain standpoint it has been shown to contain endometriosis commonly in women with stage 3 and 4 endometriosis. 1. To perform an appendectomy, it is important to examine the surrounding area for adhesive disease and be sure you can fully visualize the base of the appendix. Next grasp the tip of the appendix using a locking grasper. 2. Use the harmonic scalpel to cut the midpoint of the mesoappendix, then separate the mesoappendix from the appendix to the level of the appendicular insertion into the cecum. 3. Place TWO endoloops at the base of the appendix and firmly deploy. 4. From the base of the appendix, milk the contents distally, then deploy a third endoloop 1 cm distal to the double ligature. 5. Transect the appendix between the ligatures using the harmonic scalpel. 6. Typically, we would then place the appendix in an endobag and remove it from the abdomen, but in the interest of time we will lay it out of the way of the dissection in the upper abdomen. Peritoneal and Diaphragmatic Resection of Endometriosis The procedure for removing peritoneum from the sidewall and the 31

32 diaphragm is similar. If the diaphragm is easily visible, you can elect to dissect here, however resecting a portion on the pelvic sidewall, will augment the dissection, so we recommend practicing this on the pelvic sidewall for now. 1. Use a Maryland dissector to grasp and elevate a portion of peritoneum a few mm from the lesion of interest. 2. Incise this peritoneum making a 5mm cut, trying to only cut the bilayered peritoneum in your grasper. (In the live patient, we usually grasp inferiorly first if possible so that if bleeding occurs it does not obscure borders of the dissection.) 3. Undermine the peritoneum so that only the peritoneum is resected. In a larger specimen, pull the peritoneum medially, and use the endoshears to brush away subcutaneous fat. 4. Once the desired area of dissection is undermined, transect the peritoneum. THE URETER 1. Grasp and tent the peritoneum overlying the ureter at the pelvic brim with a Maryland dissector from the port contralateral to the side of dissection. Once the peritoneum is tented, use endoshears to make a 3-5mm nick in the peritoneum. 2. An ipsilateral instrument such as a blunt locking grasper can now be place into the retroperitoneal space and used to undermine the peritoneum overlying the ureter. 32

33 3. THE ASSISTANT SURGEON ON THE CONTRALATERAL SIDE GRASPS THE INFERIOR PERITONEAL EDGE WITH A MARYLAND GRASPER PROVIDING MEDIAL TRACTION. THIS TRACTION IS THE MOST IMPORTANT PART OF THIS SUCCESSFUL DISSECTION. The goal is to develop an incision along the pelvic sidewall terminating at the insertion of the uterosacral ligament into the utero-cervical junction on the ipsilateral pelvic sidewall. 4. Undermine the peritoneum a few centimeters at a time, cutting only where the peritoneum is visualized to be thin. (Remember the ureter is intimate with the medial peritoneum that makes up the medial aspect of the broad ligament.) A great way to keep the ureter in view is to dissect only immediately anterior to the it. It is a durable structure, and does not commonly bleed unless met with sharp tipped instruments. 5. Continue the dissection until you reach the Tunnel of Wertheim, the ureteric tunnel at the level of the cardinal ligament. The Cardinal ligament is one of the borders of the pararectal space. THE RETROPERITONEAL VESSELS 1. You will encounter the internal iliac artery at the pelvic brim near the ureter. This structure can be dissected in a similarly to the dissection of the ureter. The internal iliac vein is typically deep and lateral to the structure. 2. Identify branches of the internal iliac artery. Typical branches of the anterior trunk of the internal iliac artery are the middle rectal artery, 33

34 uterine artery, vaginal artery, obturator artery and superior vesical artery. The superior vesical artery is the terminal branch and will continue coursing anteriorly until it becomes the occluded medial umbilical ligament (the embryonic remnant of the previously patent umbilical arteries). 3. Identify the origin of the uterine artery. As a general guide, the uterine artery is easily identifiable as it branches medially and it has a tortuous appearance. 34

35 The vaginal, obturator, and superior vesical arteries are typically caudad to the uterine artery. The middle rectal often branches prior to the origin of the uterine artery but courses posteriorly as would be expected. Expect significant variability among these branches, even among anterior and posterior trunk branches, as some anatomists do not even make the distinction of the 2 trunks due their variability. Note that caudal to the bifurcation of the external iliac artery, the posterior trunk of the internal iliac artery branches and sprouts the iliolumbar, lateral sacral and the superior gluteal arteries. In the interest of time we will not fully dissect out the branches of the posterior trunk. Source: (internal-iliac-arteries-mjw jpg) 35

36 EXTERNAL ILIAC SYSTEM AND PELVIC NERVES At this point, we will move cephalad along the sidewall to explore the external iliac system as well as nerves in the anatomic proximity. At the level of the pelvic brim, the common iliac artery can be seen branching anterolaterally. The artery is more prominent than the vein, which is located behind it caudally. 1. Continue the dissection anteriorly along the external iliac artery. 2. Laterally and immediately cephalad to this structure, the belly of the large psoas muscle can be seen. Continue the dissection parallel to this structure. 3. Identify the genitofemoral nerve running directly parallel to this structure along the belly of the psoas. It branches anteriorly into the femoral and genital branches of the genitofemoral nerve. 4. Dissect further cephalad and lateral to the psoas muscle to find the thick femoral nerve. It can be seen coursing parallel to the psoas major (after emerging from it posterolaterally). After it leaves the pelvis, it travels between the psoas major and iliacus just deep to the inguinal ligament to the medial aspect of the thigh. 5. Identify the lateral femoral cutaneous nerve. Sometimes it can be seen just cephalad to this structure and is a generous sized nerve as well, but much smaller than the femoral nerve. It has a highly variable route through the abdomen and pelvis and may or may not be seen in this area. 36