Failure of Ejaculation

Given the young age group in which RPLND is typically performed, preservation of fertility is an important consideration. The process of emission during male orgasm is a complex reflex coordinated by the sympathetic nervous system; the nerves involved in this reflex are at risk during surgical dissection. Thankfully, damage to the sympathetic innervation on only one side will typically not result in loss of antegrade ejaculation. This physiologic principle is the basis for the evolution of the RPLND technique over the last few decades.

Knowledge of the neural anatomy of the retroperitoneum is critical in order to prevent injury. The sympathetic chains run parallel to the great vessels in the space between the psoas muscle and spinal column. The right sympathetic chain is posterior to the inferior vena cava (IVC), while the left sympathetic chain is posterolateral to the aorta. At the level of L1 and L2, the sympathetic chain gives off post-ganglionic sympathetic nerve fibers, also known as lumbar splanchnic nerves, which form the intermesenteric plexus over the anterior surface of the aorta ( Fig. 40.1 ). The aortic plexus is composed of four bilaterally symmetric ganglia: the right and left spermatic ganglia, the inferior mesenteric ganglion on the left, and the prehypogastric ganglion on the right ( Fig. 40.2 ). The sympathetic nerves from the aortic plexus continue into the hypogastric plexus, typically located between the two common iliac arteries, to eventually innervate the pelvic viscera.

Inferior vena cava and aorta are skeletonized and encircled with vessel loops during robotic RPLND. Post-ganglionic sympathetic nerve fibers running over the aorta are spared.

Sympathetic ganglia of the aortic plexus. IMG, inferior mesenteric ganglion; LSG, left spermatic ganglion; LSN, lumbar splanchnic nerve; PHG, prehypogastric ganglion; RSG, right spermatic ganglion; SCG, sympathetic chain ganglion.

(From Beveridge TS, et al. Anatomy of the nerves and ganglia of the aortic plexus in males. J. Anat. 2015; 226(1):93-103.)

Damage to any of these neuronal structures during the surgical dissection may result in failure of antegrade ejaculation postoperatively. To prevent injury, great care must be taken when controlling the lumbar vessels, which are intimately involved with the sympathetic chain. Also, post-ganglionic sympathetic nerve fibers on the left side must be isolated with a vessel loop prior to performing “split and roll” over the aorta. This is in contrast to the IVC, where significant nerve tissue is not encountered on the anterior surface.

While failure of antegrade ejaculation was a consistent outcome during early, wide boundary bilateral RPLND, more recent series report preservation in 85–100% of patients, and 91% in the largest series of robotic RPLND to date. This is partly from adoption of nerve sparing techniques, in which the sympathetic chain, post-ganglionic fibers, and hypogastric plexus are identified and meticulously dissected. It is also a result of instituting modified templates for RPLND, which aim to resect all potential disease and landing zones on the ipsilateral side, while limiting dissection of the contralateral side, especially below the inferior mesenteric artery. The particular template used should never compromise cancer control to preserve antegrade ejaculation.

Patients should be asked about their plans for having children and should be offered sperm banking prior to surgery. If there is failure of antegrade ejaculation postoperatively, administration of pseudoephedrine may be useful in select patients with true retrograde ejaculation (as compared with failure of emission). In those with failure of emission, electroejaculation has been shown to successfully produce motile sperm in 87% of men. If no viable sperm can be obtained in this fashion, testicular sperm extraction is typically the last resort.

Lymphocele

As in the rest of the body, retroperitoneal lymphatics run in close association with the vasculature. The lymph from the common iliac nodes passes to the right and left lumbar lymph nodes, which lie on either side of the IVC and aorta. The lymph from the descending colon, kidneys, ureters, and testes also drain into these nodes. The efferent vessels from these nodes then form the lumbar lymphatic trunks, which then join with the intestinal lymphatic trunks to form the proximal thoracic duct. The beginning of the thoracic duct will variably form a saccular dilatation known as the cisterna chyli, found anterior to bodies of the L2 or L1 vertebra between the right crus of the diaphragm and the aorta. The size and shape of this structure varies considerably between patients, if present at all. Often, there will only be a plexus of lymphatic trunks coalescing into the thoracic duct.

Controlling the retroperitoneal lymphatic vessels at the time of dissection is the most important technique to prevent lymphatic complications, including lymphoceles, which are described below, and chylous ascites, which is described in the following section. In addition to the lymphatic channels mentioned above, special attention should be paid to ligating the numerous lymphatic channels when reflecting the duodenum and pancreas off the left renal vein underneath. The same is true when mobilizing the tail of the pancreas near the ligament of Treitz.

A lymphocele is a collection of lymphatic fluid that accumulates in the retroperitoneum after damage to any of the lymphatic vessels during RPLND. Small lymphoceles are common after RPLND, are typically asymptomatic, and require no treatment. However, lymphoceles can become clinically significant if they are large, causing abdominal fullness and discomfort, if they compress other structures in the retroperitoneum such as the ureter or the inferior vena cava, or if they become infected.

If there is a clinical suspicion for postoperative lymphocele, a CT with contrast, or other cross-sectional imaging, should be obtained. Typically, a lymphocele will be identified as a thin-walled cystic structure in the retroperitoneum with simple fluid within. If there is significant loculation, enhancement of the wall, or air within the structure, there should be a high concern for abscess or infected lymphocele, especially in the presence of fevers. These should be treated with percutaneous drainage and antibiotics. The management of noninfected lymphoceles will be discussed in the pelvic lymphadenectomy section later in this chapter.

Chylous Ascites

Intraoperative injury to the larger lymphatic structures within the retroperitoneum, namely the major lymphatic trunks or cisterna chyli, can result in continuous lymphatic leakage that outpaces reabsorption. This fluid will accumulate within the abdomen and cause increasing abdominal distention and patient discomfort. This is known as chylous ascites. In some cases, this can also lead to dyspnea from increased intraabdominal pressure on the diaphragm or from lymphatic leakage into the thorax itself. The latter is usually a result of injury to the thoracic duct during retrocural dissection.

Chylous ascites can occur following RPLND for any indication, including renal cell carcinoma ( Fig. 40.3 ). In GCTs, it is a fairly rare complication but rates vary based on the setting of RPLND. In primary RPLND, the rate is approximately 2%, compared with 2–7% in pcRPLND. In laparoscopic RPLND rates of chlyous ascites range from 1% to 7%. Patients that require resection of the IVC during pcRPLND are at increased risk for chylous ascites, presumably from increased peripheral venous pressure that is transmitted to the lymphatic system. In a series of 603 patients undergoing pcRPLND, half of all patients with chylous ascites had resection of the IVC at the time of surgery.

Chylous ascites 2 weeks after left nephrectomy and retroperitoneal lymph node dissection for advanced renal cell carcinoma.

If chylous ascites is suspected after RPLND, the patient should be percutaneously drained and the fluid sent for analysis. High lymphocyte, protein, and triglyceride levels confirm the diagnosis. Since the majority of chyle is made up of chlyomicrons converted from dietary fat, the first step in management of these patients is to modify their diet to one high in protein and low in fat. The dietary fat should be primarily composed of medium chain triglycerides, which are transported directly to the portal circulation. This type of diet limits the flow of chyle into the lymphatics, promoting spontaneous closure of the injured vessels. Although time to resolution is variable, it typically takes a number of weeks or longer to completely resolve with conservative measures. This may result in repeated paracentesis while awaiting resolution of the ascites. The decision to leave an indwelling drain is controversial. Proponents of indwelling drains cite the ability to track the output and prevent repeated paracentesis, while opponents worry about the increased rate of infection and peritonitis.

If the chylous ascites does not resolve with a fat restricted diet, the second-line option is complete bowel rest with total parenteral nutrition. Evans et al. reported resolution of chylous ascites in 77% of patients with parenteral nutrition and paracentesis with or without abdominal drain placement. A number of studies also support the use of octreotide, a somatostatin analog, as another method to attenuate the flow of intestinal lymph. This should be started at a dose of 100 µg subcutaneously three times a day, but can be titrated up to 12 mg via continuous infusion. Octreotide has proven to be useful both on its own and in conjunction with total parenteral nutrition and medium-chain triglyceride diet.

If these conservative measures do not resolve the ascites, more aggressive approaches may be necessary. Bipedal lymphangiography along with injection of iodinated poppy seed oil has been shown to resolve chylous leaks, especially those classified as minor (seen only on CT after lymphangiography, not on radiography) ( Fig. 40.4 ). The amount of leakage per day with a drain in place is predictive of resolution with lymphangiography. In patients with leakage less than 200 mL/day after conservative measures, lymphangiography was successful in 97% of patients in one study. If lymphangiography itself does not resolve the leak, it can still be a useful adjunct prior to surgery to ligate the leaking vessels. Other approaches to refractory chylous ascites described in the literature include local radiation, sclerotherapy, and peritovenous shunting. However, the latter method is associated with significant morbidity and should be reserved for cases in which conservative measures fail.

Lymphangiography with poppy seed oil in a man with refractory chylous ascites following retroperitoneal lymph node dissection (RPLND) for nonseminomatous germ cell tumor.

Vascular Complications

The most feared and potentially catastrophic complication of RPLND is vascular injury. Specific management of vascular injury is discussed in detail in Chapter 10 , but here we discuss injuries specific to RPLND. While rare in the primary setting for germ cell tumors, injury to major vessels is a significant risk in patients undergoing pcRPLND or in patients undergoing nephrectomy with significant retroperitoneal adenopathy.

In the pcRPLND setting, the factors responsible for this increased risk are twofold. First, there is a dense inflammatory reaction within the retroperitoneum after chemotherapy in these men, which makes dissection along anatomic fascial planes much more difficult. Also, pcRPLND is more likely to be performed in men with larger, advanced tumors, some of which can invade adjacent organs or vascular structures. In a nationwide study of patients undergoing RPLND between 2007 and 2012, the rate of adjunctive procedures, such as nephrectomy or vascular reconstruction, was 19% in the post chemotherapy setting, compared to 1% during primary RPLND.

When the need for pcRPLND arises, a thorough evaluation of the patient and all preoperative imaging is paramount. Clues to vascular invasion present on physical exam include lower extremity edema and well-developed abdominal collateral circulation. A large bulky tumor that abuts major vascular structures on CT scan, especially on the right side, suggests that vascular reconstruction may be necessary ( Fig. 40.5 ). While not standard of care, MRI may be useful to further delineate vascular anatomy and the likelihood that the retroperitoneal mass invades adjacent structures.

Large mass posterior to inferior vena cava (IVC) (star) in axial (A) and sagittal (B) views. The mass both compresses the vein and displaces it anteriorly.

In all cases, the surgeon performing pcRPLND must be keenly aware of variations in vascular anatomy and must be comfortable with vascular control techniques. Given the complexity of the operation, pcRPLND should be performed in referral centers by experienced surgeons whenever possible. It is also prudent to have a vascular surgeon available to assist with major reconstruction if it becomes necessary.

Venous Complications

Venous hemorrhage can be a significant problem in pcRPLND, especially when dealing with bulky right-sided masses that are encroaching on the IVC and its tributaries. Although injury to vessels should be carefully avoided, transection of most major veins, including the IVC, can usually be overcome without reconstruction, thanks to the rich supply of collaterals in the abdomen and pelvis. The exceptions to this rule are the superior mesenteric, portal, and right renal veins. Damage to these vessels almost invariably requires reconstruction.

One of the most common areas of difficulty is the ligation of the fragile lumbar veins draining into the IVC. While classically described as entering the IVC at each lumbar level, there can be significant variation in the number and location of lumbar veins. In one study from Indiana University, the lumbar venous anatomy was examined in 102 consecutive RPLNDs. The authors noted that the number of infrarenal lumbar veins may vary from 0–4 on the right and 1–4 on the left. Also, a significant number of patients had two or more lumbar veins that combined into a common trunk before draining into the IVC, and 43% of patients had a lumbar vein that entered the left renal vein.

The lumbar veins can easily be avulsed by excessive traction or sheared by excessive force during ligation. To maximize exposure, the IVC should gently be retracted while the lumbar vessels are controlled by suture ligature or hemoclips. If a lumbar vessel is avulsed, it will often retract into the posterior wall musculature or vertebral foramen, resulting in bleeding that may be difficult to control. In these cases, the surgeon may use a sponge stick to compress the psoas muscle against the vertebral body at that level, thereby compressing the lumbar vein and ascending lumbar vein that runs under it. If the bleeding vessel cannot be controlled directly, the psoas muscle may be sutured to the paraspinal ligament underneath. This will usually control the bleeding and preclude the need for retro-psoas exploration.

Unlike the right renal vein, the left renal vein has a longer course and generally has multiple tributaries. Dissection of a large para-aortic mass can obscure the points of drainage of the gonadal, adrenal, or lumbar veins, resulting in injury to the left renal vein. Small lacerations can be repaired with nonabsorbable suture, usually 5-0. If the vessel is transected, avulsed, or there is a large laceration, the need for reconstruction is not clearly indicated.

Much of the data regarding left renal vein ligation come from the vascular surgery literature. Mehta et al. found that postoperative renal functional outcomes were similar between 48 patients undergoing abdominal aortic aneurysm (AAA) repair and left renal vein ligation without reconstruction, and 213 patients with intact renal veins. Stability of renal function after ligation of the left renal vein has been confirmed to at least 1 year after surgery. However, other authors argue that reconstruction of the left renal vein should be attempted, if possible, in order to better preserve preoperative renal function.

Although the above studies are useful to understand the general morbidity of left renal vein ligation, the hemodynamics and drainage of the left kidney in the context of retroperitoneal malignancy are different. In cases where the retroperitoneal mass chronically occludes the left renal vein, collaterals are often well developed, and ligation is likely to be well tolerated. That being said, patients with poor preoperative renal function and those with a solitary left kidney would probably benefit from repair. Similarly, if collateral vessels draining the left kidney are sacrificed during the course of dissection, the renal vein should be repaired. Of note, ligation of the right renal vein without reconstruction will almost invariably lead to loss of the right kidney.

In both renal cell carcinoma (RCC) and GCTs, a small, but not insignificant portion of cases may involve a mass that encases the IVC, invades the wall, or has tumor thrombus extending into its lumen. Also, in the setting of pcRPLND, the severe desmoplastic reaction after chemotherapy may make dissection of the mass from the wall of the IVC impossible. In all of these cases, en bloc removal of a portion of the IVC may be necessary. In a large study of 955 patients undergoing pcRPLND, Beck and Lalka reported 6.8% required infrarenal IVC resection, with almost one-third of those resected harboring tumor within the cava.

Thanks to abundant collateral venous flow, the infrarenal IVC may be sacrificed in order to gain a complete resection and improve survival. However, patients undergoing caval resection can have significant acute and chronic disability. The decreased venous return causes a rise in peripheral venous pressure, leading to increased secretion of lymphatic fluid and risk of postoperative chylous ascites. The increased peripheral venous pressure is also responsible for edema and chronic ulceration of the lower extremities, which can be extremely difficult to treat. Lastly, venous thromboembolism may occur as a result of increased pressures and turbulent flow.

The morbidity of IVC resection is closely related to the chronicity and extent of IVC occlusion. In the case of acute occlusion, where collateral vessels have not had a chance to form, most patients will suffer significant disability. Donaldson et al. discussed long-term outcomes of patients undergoing acute IVC ligation to prevent pulmonary embolism and noted that 61% of their cohort had some degree of leg swelling postoperatively. Stasis ulcers or edema poorly responsive to compression stockings was found in 30% of the same group.

In contrast, there appears to be only minor changes in venous hemodynamics after resection of an occluded IVC. Many authors have demonstrated that transection of the IVC in patients with tumor involvement does not result in significant long-term morbidity in most patients. Spitz et al. reported lower extremity symptoms in four of 11 patients 6 months after IVC resection during RPLND, but these were generally mild. In the study by Beck and Lalka mentioned earlier, of the 20 patients for whom disability scores could be calculated, only two had moderate disability, and one had severe disability at long-term follow-up. In their cohort, Blute et al. reported that no patients had disability that precluded them from working and 70% of patients did not need compression stockings for daily activity of up to 8 hours. Furthermore, their study suggests that venous collateralization continues to occur after IVC resection, as many patients had postoperative improvement of their preoperative disability scores. This has been confirmed in other reports.

Given the available evidence, IVC reconstruction is not necessary in patients with chronic complete, or near complete, occlusion. Preoperative imaging with MR angiography can help to define the extent of tumor involvement and the degree of IVC occlusion, as well as the degree of collateral vessel compensation. If the IVC will not be reconstructed, it is critical to spare these collateral vessels during the dissection, as they are responsible for collateral drainage into the azygous and hemi-azygous system when the IVC is ligated.

In cases where the IVC is only partially occluded, a number of options are available. If feasible, a portion of the IVC can be resected and repaired primarily. The accepted belief is that the IVC may be narrowed by up to 50% of its original diameter without resulting in significant consequence. Alternatively, a patch graft may be used for larger repairs. These types of scenarios have been managed successfully via a minimally invasive approach, with low overall morbidity.

If the IVC must be transected completely and reconstruction is indicated, a biologic or synthetic graft can be used. Reconstruction with a polytetrafluoroethylene (PTFE) graft is most common and has been shown to prevent lower extremity complications in nearly all patients. However, patients undergoing grafting have a higher rate of postoperative venous thromboembolic (VTE) events and the graft itself can thrombose. Also, grafting adds significant operative time to an already lengthy procedure. A further consideration is that patients undergoing IVC resection have advanced disease, and many of them may require chemotherapy postoperatively, rendering them immunocompromised. This results in at least a theoretical increased risk of graft infection.

Venous Anomalies

Surgeons performing RPLND should be aware of possible variations in retroperitoneal venous anatomy. These variations can further complicate an already difficult dissection, especially if not anticipated or detected on preoperative imaging. The most common anatomic abnormalities are a double vena cava, a left-sided IVC, a circumaortic left renal vein (circumaortic renal collar), or a retroaortic left renal vein. Complete situs inversus is also possible, but very rare.

A double vena cava occurs in as many as 2–3% of all people, based on cadaveric studies. The left-sided trunk typically joins with the left renal vein and crosses the midline, either posterior or anterior to the aorta, to drain into the right-sided trunk, which then ascends into the thorax normally. Typically, the right-sided trunk is dominant, but this is variable.

Transposition of the vena cava or left-sided cava is a rare anomaly, occurring in approximately 0.5% of patients. If present, the vena cava will ascend on the left side until the level of the renal vessels, where it will typically cross the midline anterior to the aorta and caudal to the superior mesenteric artery. It then normally ascends into the thorax. The transposed vena cava may also cross posterior to the aorta, but this is less common.

Anomalous drainage of the kidneys can also be problematic if not recognized. In up to 8% of the population, both an anterior and posterior branch of the left renal vein is present, encircling the aorta. This is also commonly referred to as a circumaortic collar. A somewhat less common variation is a retroaortic left renal vein, which occurs in approximately 3% of the population. Recognition of a retroaortic left renal vein is especially important because it may be mistaken for a lumbar vein and inadvertently ligated. Of note, more than one right renal vein can also be present.

Arterial Complications

The best approach to preventing arterial injury is to have a sound understanding of vascular anatomy. Unlike the venous system, transected major arteries should be repaired in the vast majority of circumstances. The only exception to this rule is the inferior mesenteric artery, which may be divided for better exposure to aortic dissection. Unless the patient has significant atherosclerotic vascular disease, the left colon will receive collateral blood supply through the marginal artery and the arch of Riolan.

During exposure of the retroperitoneum for RPLND, the duodenum and pancreas are reflected cephelad along with the small bowel, cecum, and right colon. Before placing a self-retaining retractor, great care should be taken to ensure the superior mesenteric artery (SMA) is not compressed or injured. A similarly cautious approach must be taken to dissection of a suprahilar mass, where the SMA is again at risk. Failure to promptly recognize an SMA injury leads to ischemic bowel and a generally catastrophic outcome.

Multiple renal arteries occur fairly consistently in about one-quarter to one-third of all patients. An accessory or polar renal artery can originate at the level of the renal hilum or at a variable distance caudal to the main renal artery. Accessory right renal arteries that arise caudal to the renal hilum can pass anterior to the vena cava and are at higher risk for injury, especially if not detected on preoperative imaging. Repairing these smaller vessels is very difficult, so they are best avoided.

Injury to the main renal artery is typically more common on the left because the lymphatic drainage on that side is just inferior to the hilum. Intense desmoplastic reaction after chemotherapy or dissection of a large left-sided mass may ultimately result in nephrectomy. In recent reports, 10–14% of patients undergoing pcRPLND will require adjuvant nephrectomy, predominantly on the left. The right renal artery is primarily at risk during dissection of bulky interaortocaval masses.

Although injury to the aorta is rare, resection and replacement may be necessary. In the largest series to date, aortic substitution was required in just 1% of 1250 pcRPLND operations. However, a smaller, more recent series cites a much higher rate of 9%, likely as a result of patient selection. The need for repair arises when a subadventitial plane is created in the course of removing a densely adherent mass. Removal of the adventitia along with the mass substantially weakens the aortic wall and may result in postoperative aortic aneurysm or rupture. In cases where large segments of the adventitia are peeled away in the course of dissection, it is generally a good idea to perform aortic substitution with a synthetic graft ( Fig. 40.6 ).

A, Large para-aortic mass in a patient with metastatic testicular cancer (star). B, Mass (star) unable to be completely resected from the adventitial wall of the aorta. C, Affected aorta resected and replaced with polytetrafluoroethylene graft.

Gastrointestinal Complications

Gastrointestinal complications are fairly rare and can usually be avoided by careful handling of the bowel and placement of retractor blades. Sometimes, mobilization of the duodenum can result in postoperative pancreatitis. This manifests as nausea and vomiting in the setting of elevated amylase and lipase levels. It will resolve with conservative dietary management in the vast majority of cases.

Similarly, excessive manipulation of the bowel or small serosal abrasions may result in postoperative ileus. This happens in approximately 2% of patients undergoing pcRPLND and is more likely to occur as the extent of dissection increases. Conservative management with nasogastric suction and bowel rest is typically effective in resolving this issue.

The bowel can also be directly injured, especially when dissecting the duodenum away from a densely adherent retroperitoneal mass during pcRPLND. If an enterotomy is created, it should be closed in two layers. Furthermore, omental interposition between the injured bowel and the great vessels is prudent in order to prevent formation of an abscess or aorticoduodenal fistula. At the end of the RPLND, it is important to inspect the bowel so that any injury can be primarily repaired. Lastly, the posterior layer of peritoneum should be loosely reapproximated to avoid bowel adhering to the anterior surface of the retroperitoneal vessels.

Obturator

The obturator nerve arises from the anterior rami of the L2–L4 spinal nerves in the lumbar plexus, travels through the fibers of the psoas major, and pierces the medial border of the psoas muscle at the pelvic brim. It then runs along the lateral pelvic sidewall deep to the external iliac vessels, lateral to the internal iliac vessels and ureter, and superficial to the obturator vessels. It eventually leaves the pelvis through the obturator canal with the obturator vessels to provide motor innervation for the medial thigh muscles, which adduct the leg. It also provides sensory innervation to the skin of the medial thigh. Of note, the obturator nerve does not innervate any structures within the pelvis, so there are no branches that are at risk during PLND.

The obturator nerve itself can be injured during the removal of the fibro-fatty lymph node containing tissue surrounding the nerve. Damage can occur in a number of ways, including partial or complete transection, crush injury from direct application of instruments or clips, excessive traction, or the use of electrocautery in proximity to the nerve. The severity of clinical symptoms will depend on the type and extent of injury.

The most common presentation of obturator neuropathy involves altered sensation on the medial thigh, ranging from sensory loss to paresthesias and pain. These symptoms can extend from the groin down to the medial knee. They may be exacerbated by maneuvers that stretch the nerve, which include extension and abduction of the leg. Weakness of adduction and internal rotation of the thigh can be present to varying degrees. Severe weakness can manifest as a gait abnormality characterized by an abnormally abducted and externally rotated ipsilateral hip. If the diagnosis is in doubt, electromyography can be helpful.

The most effective method of preventing obturator nerve injury is to understand the anatomic course of the nerve and its relationship to other structures in the pelvis. Great care should be taken when dissecting and placing clips within the obturator fossa. Small collateral vessels should be controlled before proceeding with the dissection. Lastly, division of the proximal and distal node packet should only be performed after the course of the entire nerve is visualized.

The reported incidence of obturator nerve injury is less than 1% in most studies. However, mild symptoms that do not produce significant disability are likely not reported by patients, so the true incidence is almost certainly higher. Although rare, this injury is more likely to occur in patients with prior chemotherapy or pelvic radiation, or tumor involvement of the obturator nodes. The inflammatory reaction associated with these conditions makes dissection of the nerve away from the node packet more difficult.

Severe injuries such as partial or complete transection, recognized intraoperatively, should be primarily repaired with microsurgical techniques at the time of surgery. If an end-to-end tension-free primary anastomosis is not possible because of retraction of the transected ends, autologous sural nerve can also be used with good success. As long as the nerve is promptly repaired, motor and sensory function is typically restored by 1 year after surgery.

Little is known about the management of patients that have persistent severe weakness and/or pain despite physical therapy. There is some evidence that surgical exploration may identify an unrecognized major injury to the nerve. Repair of the nerve, even months after the initial injury, has resulted in improved adductor muscle strength.

Genitofemoral

The genitofemoral nerve arises from the L1 and L2 spinal nerve roots in the lumbar plexus and pierces the fibers of the psoas muscle. It then runs along the anterior surface of the psoas, where it splits into its genital and femoral branches. The femoral branch travels underneath the inguinal ligament and provides sensory innervation to the upper medial thigh. The genital branch travels into the inguinal canal and supplies sensory innervation to the skin of the anterior scrotum in men and the mons pubis and labia majora in women. It also supplies the motor fibers innervating the cremaster muscle in men.

Damage to the genitofemoral nerve during pelvic lymphadenectomy is most likely to occur where the nerve travels just lateral to the common and external iliac vessels. The key to preventing injury is to start the nodal dissection proximally and to mobilize the iliac vessels medially in order to visualize the nerve. It may be intimately involved with the nodal tissue surrounding the vessels, so a careful split and roll technique should be used.

Femoral

The femoral nerve arises from the anterior rami of the L2–L4 spinal nerves in the lumbar plexus, travels through the fibers of the psoas major, and emerges at its lateral border. It then travels in the groove between the psoas and iliacus muscles until it passes underneath the inguinal ligament to innervate the muscles responsible for hip flexion and extension at the knee. It also supplies cutaneous branches that innervate the anterior and medial lower extremity.

Most commonly, femoral neuropathy results from inappropriate use of a self-retaining retractor in the pelvis, especially when exposing the lateral pelvis for lymphadenectomy. The nerve can be damaged by excessive traction, compression against the pelvic sidewall by the psoas muscle, or by direct compression of the nerve by the blades of the retractor. Femoral neuropathy can also occur with prolonged or exaggerated lithotomy position, which can exert pressure on the nerve as it passes underneath the inguinal ligament. Lastly, there is some evidence that arterial ischemia to the intrapelvic portion of the nerve can result in neuropathy. This seems to be more common on the left side, where there is less collateral blood supply from the deep circumflex iliac artery.

The role of self-retaining retractors is best highlighted by comparative studies in the gynecologic literature. For example, Goldman et al. performed abdominal hysterectomies on over 6000 women and noted the rate of femoral neuropathy fell from 7.5% to 0.7% when a self-retaining retractor was not used. There are also many case studies in the urologic literature that document femoral nerve injury after open radical prostatectomy or cystectomy, implicating self-retaining retractors as the cause.

The best method for preventing femoral nerve injuries in open lymphadenectomy is careful, methodical placement of self-retaining retractors. When placed properly, the retractor should only retract the rectus musculature without putting pressure on the psoas muscle. The shortest possible blades should be used, and folded lap sponges should be placed between the blades and the musculature to act as a cushion. The surgeon should check for proper positioning during placement and periodically during the operation.

When using the robotic approach, the risk of femoral neuropathy stems primarily from patient positioning in dorsal lithotomy, or on a split-leg table with extension at the hip to facilitate docking. While this injury can occur during radical prostatectomy without lymphadenectomy, PLND increases operative time. Prolonged positioning in dorsal lithotomy, especially with legs hyperabducted, externally rotated, and flexed at the hip, is a well-established risk factor for lower extremity neuropathies postoperatively. Fortunately, with the newer robotic platforms, the patient is able to remain supine while the robot docks alongside the patient, instead of at the feet. This should minimize the risk of femoral neuropathy in these patients.

Most commonly, femoral neuropathy manifests as difficulty with ambulation in the immediate postoperative period, along with altered sensation over the anteromedial thigh. The most reliable clinical signs are weakness of the quadriceps muscle and an absent or diminished patellar reflex. Patients complaining of significant pain that also have a bleeding diathesis or are on anticoagulation therapy should potentially undergo cross-sectional imaging to rule out a perineural hematoma.