by Elspeth M. McDougall, MD, FRCSC, Inderbir S. Gill, MD, M Ch
Laparoscopic kidney surgery is a relatively new addition to the minimally invasive armamentarium of urologists. The kidney may be approached using a transperitoneal or retroperitoneal access. Each approach may have unique indications. These indications are becoming defined as experience with laparoscopic urology increases. Also, both approaches are associated with complications that are specific to that access technique. This chapter outlines complications associated with laparoscopic kidney surgery under the two broad headings of transperitoneal and retroperitoneal access. The discussion is focused on laparoscopic nephrectomy, although other operative renal procedures are presented in the retroperitoneal section.
TRANSPERITONEAL LAPAROSCOPIC NEPHRECTOMY
Laparoscopic nephrectomy, as described by Clayman and colleagues in 1991, established the place of laparoscopy in therapeutic urology.1 Since that pioneering report, over 500 laparoscopic nephrectomies for benign disease have been performed world-wide; at select centers, laparoscopic nephrectomy for benign disease is currently considered a routine procedure. Recently, laparoscopic radical nephrectomy for cancer has been described.2 Central to the development of the technique of laparoscopic nephrectomy was the concept of contained intra-abdominal morcellation of large solid organs and the demonstration that precise dissection of large blood vessels could be safely performed laparoscopically.1 Although it can be performed by either the transperitoneal or retroperitoneal approach, the majority of laparoscopic nephrectomies have been performed by the transperitoneal technique.
Generally accepted indications for laparoscopic nephrectomy include most symptomatic, benign, non-functioning renal pathology. While almost all benign diseases have been treated by laparoscopic nephrectomy, one relative contraindication may be xanthogranulomatous pyelonephritis (XGP), because of its associated perirenal scarring. Laparoscopic radical nephrectomy is currently limited to select patients with T1N0M0 or T2N0N0 disease, that is small or medium sized (≤ 6 cm) renal masses without any evidence of renal vein or inferior vena cava involvement, hilar lymphadenopathy or perirenal extension.2
Contraindications to laparoscopic nephrectomy include those contraindications for open surgical nephrectomy including severe cardiorespiratory impairment, coagulopathy, and sepsis. Additionally, contraindications specific to the laparoscopic approach may include incarcerated inguinal hernia, severe obesity, large hiatal hernia and significant post-surgical adhesions.
The technique of transperitoneal laparoscopic nephrectomy has been described in detail.3 Following cuffed endotracheal general anesthesia, a nasogastric tube and urethral Foley catheter are inserted, and pneumatic compression stockings applied. Preoperative renal artery embolization or ureteral stenting are no longer performed routinely. During our early experience, the initial establishment of pneumoperitoneum and insertion of the medial ports was performed in the supine position. The patient was then placed in the flank position for the remainder of the procedure (Figure 1a).
Currently, the patient is placed in the lateral decubitus, flank position at the outset; lateral insufflation and port placement is performed (Figure 1b). Ports include a 12 mm site at the lateral border of the abdominis rectus muscle just above the umbilicus, a 12 mm port just below the costal margin on the anterior axillary line, a 5 mm port just below the level of the umbilicus on the anterior axillary line, and two 5 mm ports on the posterior axillary line, one just below the costal margin and the other above the iliac crest (Figure 1c). The ipsilateral line of Toldt is incised and the colon mobilized medially to the duodenum (right side) or to the aorta (left side). The ureter is retracted laterally and mobilized proximally towards the inferior renal pole. The lower and upper renal poles are mobilized and retracted laterally, placing the renal hilum on gentle traction. The renal artery and vein are individually dissected, clipped and divided. Following ureteral transection, the kidney is freed completely and the specimen is placed in an impermeable sack for intact removal or intra-abdominal morcellation.
A key anatomic concern regarding the transperitoneal laparoscopic approach is the retroperitoneal location of the kidney. In this instance, the ipsilateral colon must be mobilized and retroperitoneal fat dissected to identify the ureter and kidney. The ureter is often situated in a medial location adjacent to the inferior vena cava or the aorta. During the transperitoneal approach, renal hilar vessels are approached in a manner comparable to open surgery. The renal vein is usually identified initially followed by the renal artery and the pelvis. Access to the upper pole is easier during transperitoneal laparoscopy as compared to retroperitoneoscopy.
When performing laparoscopic radical nephrectomy or nephroureterectomy for renal tumor disease the same principles of open expirative surgery must be replicated.2,4 Renal vessels are individually secured, the artery is clipped and transected followed by ligation of the renal vein. The kidney is dissected within an intact Gerota’s fascia and, in the case of laparoscopic nephroureterectomy, the entire ureter, including a cuff of bladder, is included in the surgical specimen. These specimens are usually removed intact to facilitate accurate pathologic staging of the tumor and reduce the risk of tumor spillage or seeding. Laboratory evaluation has confirmed the impermeability of the entrapment sack and its efficacy to secure tumor containing specimens.5 Intact removal is performed, after the specimen is secured within the organ entrapment sack, by a 2 to 4 inch extension of the fascia and skin incision at one of the port sites. This incision is most appropriately performed at the midline, subcostally or in the pararectus region to reduce postoperative hernia formation.2
Complications: In a recent multi-institutional study of 185 patients undergoing laparoscopic nephrectomy, 30 patients (16%) had 34 complications.6 The complication rate following laparoscopic nephrectomy for benign disease is 12%. The complication rate following laparoscopic radical nephrectomy for cancer is 34%. The overall complication rate following laparoscopic nephrectomy is 16%. There was no mortality. The incidence of complications decreased with experience; 71% occurred during the initial 20 cases at each institution.
Complications can be access-related (2.2%), intraoperative (2.7%), or postoperative (13.5%). The most common access-related complication was trocar-site hernia formation (two patients). Intraoperatively, vascular injury occurred in three patients (1.6%); two of these three patients required emergent conversion to open surgery. In one instance, a misfired GIA stapler resulted in back-bleeding from the distal incised end of the renal vein; at open exploration, the proximal renal vascular stump was noted to be securely stapled. While performing laparoscopic radical nephrectomy in a patient with severe periaortic fibrosis, the superior mesenteric artery was mistaken for the left renal artery and ligated. Interposition graft repair was performed by open surgery. In one patient, an anomalous branch of the inferior vena cava was injured. One patient sustained an intraoperative retractor injury to the spleen which was felt to be adequately controlled by blunt pressure with a laparoscopic Kittner; recurrent postoperative bleeding necessitated a secondary open surgical splenectomy.
Postoperative complications (13.5%) involved the gastrointestinal tract (3.2%), cardiovascular system (3.2%), genitourinary system (2.2%), musculoskeletal system (1.1%), and miscellaneous (1.6%). Of these, major complications included a controlled enterocutaneous (small bowel) fistula following a laparoscopic left radical nephrectomy. The fistula was believed to be secondary to suture penetrating a bowel loop during port-site closure following successful removal of the tumor-bearing kidney. Conservative management (hyperalimentation and bowel rest for 6 weeks) was successful. Duodenal ulcer bleed occurred in two patients.
Exacerbation of a pre-existing cardiac condition (atrial fibrillation and congestive failure) occurred in three patients (1.6%). Myocardial infarction occurred in a 77 year old patient postoperatively; this patient had undergone two previous cardiac bypass operations before the uneventful laparoscopic nephrectomy. Musculoskeletal complications included a right brachial palsy following an 8.5 hour nephrectomy in one patient, and a lateral compartment syndrome of the leg following a 7.9 hour nephrectomy in another patient.
Conversion to open surgery was required in 10 patients (elective 8, emergent 2); both emergent laparotomies were performed to control bleeding vessels. The conversion to open rate was 3% for benign disease, and 16% for renal tumors.
Laparoscopic nephrectomy is associated with a learning curve.6,7 The majority of the technical complications (64%), overall complications (71%), and conversions to open surgery (80%) occurred among the first 20 patients at each of the five institutions in the study.7
Selection and Access Related Complications: Initial assessment of the patient, prior to planned laparoscopic kidney surgery, will define those at risk. Operative and postoperative complications will be reduced by selecting patients most appropriate for this surgical approach and identifying correctable preoperative concerns.
Generally, a patient who is unfit for standard open surgical nephrectomy is unfit for laparoscopic nephrectomy. Laparoscopic nephrectomy entails a significantly longer operative time than open surgical nephrectomy (5.9 hrs vs 2.8 hrs).8 Accordingly, thorough preoperative evaluation of the cardiorespiratory status is essential. Impaired cardio-pulmonary function predisposes to intraoperative fluid overload and CO2 retention. Intraoperatively, end-tidal CO2 levels must be monitored by capnometry. As regards relative contraindications for laparoscopic nephrectomy for benign disease, xanthogranulomatous pyelonephritis usually induces a severe perirenal fibrotic reaction which may preclude laparoscopic dissection. As regards laparoscopic radical nephrectomy for cancer, McDougall’s recent report of 17 patients concluded that low stage renal cancers with size ≤ 8 cm and weighing ≤ 850 gms may be amenable to laparoscopic excision.2
Given the protracted operative time, patient positioning is of critical importance to prevent postoperative neurological sequelae. Extremities should be carefully placed in a neutral position to minimize positional stress on joints. All bony prominences should be adequately padded. In dialysis patients, arteriovenous fistulae for hemodialysis access should be protected from local or upstream compression.
Transperitoneal access for laparoscopy can be obtained utilizing a Veress needle or open trocar (Hasson) approach. While the former is suitable for an unscarred abdomen, the latter is preferable in patients with a history of multiple prior surgeries. The open (Hasson) approach however is not entirely free of complications, as bowel injury has been reported.9 Transperitoneal laparoscopic access can be obtained safely with the patient in either the supine or lateral decubitus, flank position.
Intraoperative and Dissection Related Complications: Laparoscopic surgery differs from open surgery in one important aspect: it is performed in a closed abdomen and involves discrete handling of tissues. Accordingly, insensible fluid losses and third spacing are minimal compared to open surgery. Furthermore, prolonged, massive increase of intra-abdominal pressure during pneumoperitoneum causes oligo-anuria by a variety of mechanisms: renal vein compression, renal parenchymal compression, increased total renal vascular resistance, increased ADH production and decreased cardiac output, stroke volume, and venous return.10-12 The net result is intraoperative oligo-anuria. Accordingly, fluid requirements during prolonged laparoscopic procedures such as laparoscopic nephrectomy are minimal. The anesthesiologist must be aware that only maintenance fluids should be replaced without any attempt at inducing intraoperative diuresis. Failure to limit intraoperative fluid administration may result in postoperative congestive heart failure, especially in patients with compromised cardiovascular reserve. Laparoscopic associated oligo-anuria is self-limiting, and reverses upon deflation of pneumoperitoneum in the postoperative period.
Intraoperative dissection injuries usually occur due to mechanical or thermal trauma. Vascular injuries are rare (1.6%) but require emergent conversion to open surgery in two-thirds of cases. Renal hilar dissection must be meticulous. The renal artery and vein should be mobilized separately and a 360 degree window created around these blood vessels before applying clips or staples. While in experienced hands, a hemorrhaging blood vessel may be controlled laparoscopically, prompt conversion to open surgery should be done by those less experienced. These types of complications underscore the importance of immediate availability of open surgical instrumentation in the operating room. Emergent open intervention is optimally performed by a definite, pre-planned set of maneuvers. Hemorrhage should be immediately tamponaded by a blunt laparoscopic instrument. The laparoscope is then torqued towards the undersurface of the body wall which is incised directly over the laparoscope; the laparoscopic sheath protects the underlying intra-abdominal structures from injury. Open surgical repair is performed. Occasionally, thermal injury may occur to the intestines or the ureter. Avoid indiscriminate electrocautery in the vicinity of these structures. Careful examination of hollow, tubular structures in the operative field is important prior to termination of the procedure. Typically, an unrecognized thermal injury to the ureter or bowel presents in a delayed fashion with urinary or fecal leakage. If detected intraoperatively, consideration must be given to immediate laparoscopic or open suture repair.
Recently, at Washington University a postoperative death occurred on postoperative day 3, due to multi-organ failure in an 86 year old female who underwent a laparoscopic left nephrectomy for xanthogranulomatous pyelonephritis. A specific cause could not be determined as a postmortem was not permitted. Schorr recently reported on a 62 year old female who died on postoperative day 3 following an uneventful laparoscopic cholecystectomy.13 Many of the clinical characteristics were similar to those in the Washington University patient. The initial postoperative course was uneventful. Subsequent clinical deterioration was associated with elevated liver enzymes, elevated amylase and reduced platelets. The clinical course culminated in cardiopulmonary arrest unresponsive to resuscitation. At autopsy, Schorr’s patient was found to have a superior mesenteric artery thrombosis with infarction of the small bowel distal to the ligament of Treitz and colon to the hepatic flexure. Jaffe and Russell have also reported a similar clinical experience following laparoscopic cholecystectomy.14 There are several factors which may predispose to mesenteric infarction following laparoscopic surgery, including 1) compression of splanchnic vessels secondary to increased intra-abdominal pressure, 2) decreased splanchnic blood flow, with reduction in portal blood flow secondary to increased intra-abdominal pressure, 3) increased levels of vasopressin related to carbon dioxide insufflation associated with effects on mesenteric vascular resistance, and 4) reduced vena cava blood flow secondary to the increased intra-abdominal pressure and Trendelenburg positioning.15-17 The surgeon must have a high index of suspicion for the diagnosis of mesenteric thrombosis. Prompt laparotomy, in addition to vasodilator therapy and aggressive fluid resuscitation, may improve the outcome of this major complication.
Closure Related Complications: Before terminating the laparoscopic procedure, hemostasis must be confirmed at low intra-abdominal CO2 pressure ( ≤ 5 mm Hg). Since standard pneumoperitoneum of 10 - 15 mm Hg may tamponade venous bleeders, lowering abdominal pressure unmasks these bleeding sites. All ports must be removed under laparoscopic monitoring. In adults, fascial closure of all 10 mm or larger ports must be performed under direct laparoscopic visualization. In children, however, fascial closure of even the 5 mm ports must be performed to prevent omental evisceration.18
Postoperative recovery following laparoscopic nephrectomy is usually uneventful.
Persistent, inordinate abdominal pain is ominous and merits close attention. Computed tomography is useful for evaluating intestinal integrity, the presence of bleeding or abdominal wall injury. Serial studies may be necessary if the patient does not improve clinically and initial studies are noncontributory. The patient with signs of acute peritoneal irritation may warrant laparotomy. Hemorrhage, bowel or ureteral injury, and pancreatitis must be adequately evaluated with appropriate laboratory studies in addition to radiographic imaging.
RETROPERITONEAL LAPAROSCOPIC NEPHRECTOMY
Endoscopic examination of the retroperitoneum was first described by Wickham in 1979 when the endoscopic removal of an ureteral stone was reported.19 Clayman and colleagues subsequently reported two cases of retroperitoneoscopy, including one case of a ureteral stone retrieval and another case of removal of a retained drain.20,21
Based on these reports, the development of retroperitoneoscopy in pigs at Washington University Medical School was explored to perfect a totally retroperitoneal laparoscopic nephrectomy technique. The technique was transferred to the clinical realm in December 1990 when a 51 gm hydronephrotic, poorly functioning kidney was removed using an entirely retroperitoneal approach with the patient in a prone position.22,23 However, the smaller space of the retroperitoneum made achieving a satisfactory pneumoretroperitoneum and organ entrapment of the surgical specimen difficult.
Subsequently, we returned to the transperitoneal approach for the laparoscopic nephrectomy.
In 1992, Gaur described the use of a retroperitoneal balloon to dissect the retroperitoneal space and perform laparoscopic nephrectomy with the patient in the lateral decubitus position.24 Subsequently, several investigators evaluated and reported on this technique for laparoscopic nephrectomy.25
An extraperitoneal approach to renal laparoscopy has several surgical implications. Balloon distension of the retroperitoneum facilitates direct access to the kidney and reduces the dissection necessary to expose the kidney and the need for visceral retraction. As intraperitoneal insufflation of CO2 is eliminated there is reduced peritoneal irritation by the gas which may decrease postoperative discomfort. It has also been hypothesized that retroperitoneoscopy reduces the risk of intraperitoneal contamination with tumor cells or infection. The posterior approach to the laparoscopic nephrectomy provides early exposure and control of the renal artery, followed by exposure and ligation of the renal vein. The easier exposure of the renal artery, without retraction of the renal vein, may facilitate the laparoscopic removal of the kidney.
Some investigators advocate positioning the dilating balloon, when possible, within Gerota’s fascia.24,26 However, in our experience at Washington University we have not been able to achieve this in our patient population. Pararenal positioning of the dilating balloon catheter has been dictated primarily due to the constraints of flank and retroperitoneal fat in our patients.
The disadvantages of the extraperitoneal approach to laparoscopic renal surgery include a smaller working space and more difficult identification and exposure of some anatomic structures. The retroperitoneal laparoscopic nephrectomy is better suited for the small nonfunctioning kidney without significant retroperitoneal fibrosis. Large surgical specimens and tumor bearing kidneys are better approached using the transperitoneal laparoscopic technique which facilitates organ manipulation and entrapment. Retroperitoneal anatomy is less familiar than that during transperitoneal exposure and may be confusing. Following balloon dilation of the retroperitoneal space the ureter is usually easily identified just medial to the body of the psoas muscle. During dissection on the left side of the retroperitoneum a large venous structure is usually encountered which may be mistaken for renal vein. However, note that the renal artery should be the first renal vessel encountered and the orientation of this large vein is more cephalad-caudad than the expected medial-lateral position. This large vein is the posterior lumbar and often requires ligation to completely access renal vessels. On the right side of the retroperitoneum a posterior approach may actually facilitate access to the adrenal gland and adrenal vein, particularly when the adrenal gland is positioned posteriorly and intimately associated with the inferior vena cava.
Retroperitoneal laparoscopic nephrectomy is performed with the patient in a lateral decubitus position with the affected flank exposed. A Foley catheter is placed to decompress the bladder and nasogastric drainage is used to decompress the stomach.
A ureteral catheter and superstiff guidewire are not routinely placed preoperatively, unless a difficult retroperitoneal dissection is anticipated. The flank is stretched by placing padded rolls under the contralateral flank or by elevating the kidney rest and flexing the table.
The Veress needle is inserted at the inferior lumbar triangle (i.e. Petit’s triangle) in the posterior axillary line just above the iliac crest. Carbon dioxide insufflation is performed to 15 mm Hg pressure; usually 2 liters of gas can be instilled in the retroperitoneum. The Veress needle is removed and a 12 mm port is inserted at the inferior lumbar triangle (Figure 1c). Alternately, an open Hasson-type port may be inserted after incision of the fascia.
Balloon dilation of the retroperitoneal space is performed through the initial port. Commercially available dilating devices may be selected for this technique. However, a simply constructed balloon catheter can be made by securing the middle finger of a size 8, sterile surgeon’s latex glove (Triflex latex, Baxter Health Care Corp., Valencia, CA) on to the end of a 16F red rubber catheter with two O-silk ligatures. The openings of the catheter are positioned within the glove finger. Laboratory pressure studies of fluid distension of the balloon were performed before clinical application.25 These studies showed that the balloon inflated, with normal saline, easily to 1000 cc and 2000 cc with average balloon pressures remaining < 20 mm Hg. The burst point of the balloon occurred at 4000 cc fluid volume and at a pressure never exceeding 30 mm Hg. In the clinical setting, the shape and dimensions of the inflated balloon will vary according to the restrictive anatomy of the retroperitoneal space. The balloon catheter is backloaded through a 30F Amplatz sheath until the balloon is retracted just inside the sheath. The assembled unit is inserted through the 12 mm port until the tip of the Amplatz sheath lies just at the port opening. The balloon catheter is advanced 3 to 4 cm into the retroperitoneal space, outside Gerota’s fascia. The balloon is filled with 1 liter of normal saline. The balloon is aspirated empty and removed within the Amplatz sheath to avoid entanglement on the flap valve system of the port. The 12 mm port is connected to CO2 and insufflation is performed to 12 to 15 mm Hg. The 10 mm, 30 degree laparoscope is inserted, and on initial examination the psoas muscle is easily identified. The genitofemoral nerve lies over the surface of the psoas muscle and the ureter is often also seen just medial to the psoas muscle.
An additional three ports are inserted under laparoscopic visualization; a 12 mm port is place on the posterior axillary line just below the tip of the twelfth rib (superior, posterior lumbar triangle), a 5 mm port is placed on the lateral border of the sacrospinalis muscle midway between the iliac crest and the costal margin, and a 5 mm port is inserted on the anterior axillary line just below the level of the twelfth rib27 (Figure 1c). This port arrangement forms a “T” shape. During secondary port placement or dissection an opening of the peritoneum may occur. However, CO2 insufflation pressure quickly equilibrates between the retroperitoneum and abdominal space and does not impede the performance of the laparoscopic procedure.
Initial dissection for benign disease includes incision of Gerota’s fascia and dissection of the perirenal fat off the posterior and lateral renal surfaces, exposing the kidney. The ureter is secured at the lower pole of the kidney with an 0-silk ligature passed around the ureter and drawn onto the flank, using the Carter-Thomason needle grasper, through a small flank puncture.28 This maneuver allows the ureter to be retracted laterally and inferiorly without utilizing a laparoscopic port. Dissection cephalad along the ureter identifies the renal pelvis and the hilar vessels. The posterior approach results in the renal artery being the first vessel encountered. The artery is circumferentially dissected and secured with five 9 mm, vascular clips; it is transected between the second and the third clip, leaving three clips on the arterial stump. The renal vein is then identified and circumferentially exposed. The vein is often broader than 9 mm and an Endo-GIA 30 vascular stapler (U.S. Surgical Corp., Norwalk, CT) is used to occlude and transect the vein. The final attachments of the kidney are then freed anteriorly and medially. The ureter is transected between 9 mm vascular clips. A 5 x 8 inch entrapment sack is introduced through the upper 12 mm port. The surgical specimen is deposited into the entrapment sack, morcellated and extracted along with final removal of the organ entrapment sack.29
The key step to retroperitoneoscopy is the creation of an optimum working space. Use of a 1 liter dilating balloon catheter maximally develops the extraperitoneal space. It is important that the balloon catheter is placed within the pararenal or perirenal space before inflation. Gill and colleagues recently reported complications of laparoscopic nephrectomy in 185 patients from a multi-institutional review.6 In one patient a postoperative flank hernia developed secondary to inadvertent inflation of the dilating balloon in the flat muscles of the flank which created a large space in the abdominal fascia.
Complications of retroperitoneal laparoscopic nephrectomy are otherwise similar to those associated with transperitoneal laparoscopic nephrectomy. These include complications related to access, dissection and closure of the port sites.
Access Related Complications
Access related complications constitute one of the most common problems associated with laparoscopy. Laparoscopic urological procedures tend to be of long operative duration (i.e. > 2 hours) and complications secondary to prolonged patient positioning may occur. The extremely obese or very thin patients are at greatest risk for developing nerve palsy or bruising over boney prominences as a result of prolonged pressure from lateral decubitus positioning. It is imperative to ensure adequate padding of boney prominences and support of upper and lower extremities without extreme abduction or flexion at major joints. The use of shoulder braces, when placing patients in reverse Trendelenberg, should be avoided as these are associated with brachial nerve injuries. At Washington University we have experienced a significant reduction in patient positioning complications since the institution of the urologic O.S.I. operative table (Orthopedic Systems Inc., Union City, CA). This table consists of a peripheral metal frame to which padded supports are secured and provide individualized positioning for each patient. This system eliminates pressure at the greater trochanter, shoulder and hip and reduces femoral nerve, brachial nerve and vastus lateralis injuries. Additionally, generous use of foam padding at specific pressure points, overlying boney prominences, reduces the risk of positioning complications.
Establishment of an adequate pneumoretroperitoneum is critical to successful laparoscopic extraperitoneal surgery. The closed technique, utilizing a Veress needle for initial access into the retroperitoneal space, has been our technique of choice. Strict attention to technique will avoid most Veress needle injuries. The Veress needle should be placed in the inferior or superior posterior lumbar triangle, on the posterior axillary line, as this provides the shortest distance between skin and the retroperitoneal space. We have found the inferior posterior lumbar triangle to be the most satisfactory position for this procedure. The Veress needle should be directed perpendicular to the posterior fascia. Exposure of the fascia is helpful prior to the placement of the needle. A “pop” and deflection of the spring loaded marker on the needle will be appreciated as the Veress needle passes through fascia. Several tests confirm correct Veress needle placement in the retroperitoneal space prior to initial insufflation. Aspiration of the needle, using a 10 cc syringe filled with 8 cc of normal saline, should return only gas bubbles. Aspiration of bodily fluids (i.e. blood, bowel contents or urine) indicates the needle is not in its proper location. Injection of 5 cc of saline should be performed easily and, on reaspiration, no return of fluid should be obtained. The advancement test can also help to confirm placement. In this technique the Veress needle is advanced 1 cm into the retroperitoneum and if the spring loaded marker shows no change in position this indicates that no further resistance is being met with respect to another layer of fascia or solid organ. The final test to assure correct positioning occurs at the initiation of insufflation. When infusing gas at a low rate (1 liter per minute) the retroperitoneal pressure should be less than 10 mm Hg. Initial high opening pressures or rapidly rising pressures after a small amount of insufflated gas raise the suspicion of incorrect needle placement. Approximately 2 liters of CO2 gas can usually be insufflated into the retroperitoneum at an initial pressure of 25 to 30 mm Hg. Once the initial port is successfully placed, the retroperitoneal pressure is lowered to 12 to 15 mm Hg for the duration of the procedure.
Any difficulty encountered with Veress needle retroperitoneal access dictates the adoption of the open technique of retroperitoneal access. Some surgeons routinely employ an open trocar technique for obtaining retroperitoneoscopic access.26 This technique utilizes exposure of the posterior lumbar fascia, at the tip of the twelfth rib, with a 2 to 2.5 cm skin incision. Two stay sutures of 0-vicryl (polyglactin) are secured in the fascia. This suture placement may be a challenging maneuver in an obese patient. Fascia is incised between the two stay sutures, and finger dissection performed in the retroperitoneal space, followed by placement of the blunt tipped trocar. The stay sutures facilitate securement of the occluding pyramidal portion of the trocar against the fascia. Balloon dilation is then performed through the established primary port, followed by creation of the working pneumoretroperitoneum.
Laparoscopic visualization of the retroperitoneum after initial port placement is necessary to confirm satisfactory positioning prior to the balloon dilation of the retroperitoneal space. This confirmatory examination will obviate the problems associated with balloon dilation of the superficial fascial layers secondary to improper balloon catheter placement. Gill and colleagues reported one patient in whom the dilating balloon was inadvertently inflated in the flat muscles of the flank, which created a large space in the abdominal fascia that was not recognized at operation, and the nephrectomy was completed laparoscopically.6 The patient was rehospitalized on postoperative day 10 for a flank hernia at the trocar site. In addition, one patient in whom a secondary trocar was placed through an area of muscular weakness of the abdominal wall, secondary to previous surgery, developed a Richter’s bowel hernia two days postoperatively requiring laparoscopic repair. Similarly, previous open flank incisions should be avoided as port locations to reduce the risk of subsequent hernia formation.
The placement of secondary ports may be associated with abdominal or flank wall vessel injuries and result in significant bleeding or hematoma formation. Several maneuvers can reduce the risk of these vascular injuries. All secondary ports should be inserted under laparoscopic visualization to identify major vascular structures and monitor the depth of port insertion. In addition, transillumination of the flank wall will help to identify more superficial vessels which may be lacerated from port placement. The skin incision can then be directed away from the area of the flank wall vessel. Prior to port placement a Kelly forceps is used to spread the subcutaneous tissues down to the fascia. This procedure helps to displace small subcutaneous vessels that may be in the path of the port placement and thereby reduce subsequent flank wall hematomas or bleeding.
Occasionally, despite attention to these techniques, vessels within the flank muscles may be injured during port placement. These are identified laparoscopically by bleeding from the port site dripping into the retroperitoneal space. The Carter-Thomason (Inlet Medical Inc., Eden Prairie, MN) device provides rapid placement of a hemostatic suture to control this type of bleeding. The 0-absorbable suture (36 inches) is grasped in the needle-pointed grasping jaws of Carter-Thomason grasping needle. The grasping needle is directed through the fascia, between the skin and the port, and laparoscopically positioned in the retroperitoneum. The jaws of the grasping needle are opened to release the end of the suture and then the grasping needle is removed. The grasping needle is reinserted 180 degrees from the initial insertion site and directed through the fascia, between the skin and the port, into the retroperitoneum. The end of the suture is grasped in the needle-pointed grasping jaws and drawn out through the fascia. The suture can then be tightened down over a gauze roll with a small forceps to tamponade the bleeding. At the completion of the procedure, after removal of the port under reduced pressure (i.e. 5 mm Hg), the suture is tied down securely and the port site examined laparoscopically for hemostasis. Additional sutures can be placed with the Carter-Thomason as needed to provide adequate hemostasis.
Insertion of the ports too deeply may result in injury to the kidney, especially in the presence of hydronephrosis. Laparoscopic visualization to control port placement will help to eliminate this complication. Additionally, a sharp trocar point will minimize the force necessary to enter the retroperitoneal cavity. The index or middle finger should be extended along the sheath to act as a buffer and prevent the initial thrust from pushing the trocar too deeply. By holding the elbow of the thrusting arm close to the rib cage, the wrist and hand are better stabilized for trocar insertion. A gentle twisting motion will allow the trocar to pass more smoothly through the flank musculature. Very large or hydronephrotic kidneys may be a relative contraindication to the retroperitoneal approach for laparoscopic nephrectomy due to the increased risk of organ injury during the port placement. Satisfactory port placement is restricted by the small retroperitoneal space and the large surgical specimen. Retroperitoneoscopy is better suited for the small, poorly functioning kidney.
INTRAOPERATIVE AND DISSECTION
A clear understanding of the anatomy as related to the planned operative procedure is of paramount importance with retroperitoneoscopy. This knowledge will allow the surgeon to identify major anatomic structures during dissection and avoid injury to these structures. The review by Gill and colleagues of laparoscopic nephrectomy (both transperitoneal and retroperitoneal) identified vascular injury as the most common intraoperative complication.6 This may be particularly pertinent for retroperitoneoscopy as the perirenal anatomy is not as familiar from the extraperitoneal approach compared to transperitoneal laparoscopy. Following balloon dilation of the retroperitoneal space, laparoscopic visualization usually demonstrates the psoas muscle. Just medial to the psoas muscle the ureter is seen positioned in the cephalad-caudad orientation. The great vessels (i.e. vena cava or aorta) lie within the retroperitoneal tissues between the psoas muscle and the ureter. Improper placement of retractors or dissecting instruments may result in injury to these structures. Also, insertion of a port medial to the sacrospinalis muscle in the posterior flank could traverse the body of the psoas muscle and impinge on the great vessel resulting in significant bleeding. Often dissection on the left side of the retroperitoneum, cephalad, will expose a large venous structure in cephalad-caudad orientation representing the posterior lumbar vein. This structure must be anticipated, dissected and secured with vascular clips to minimize the risk of bleeding. Bleeding from small vascular structures can usually be controlled with electrocautery or vascular clips. Laceration of the vena cava or aorta results in significant bleeding, which is magnified by the laparoscope. This clinical situation associated with hypotension or uncontrollable bleeding necessitates immediate laparotomy for definitive control of the vascular structure. For this reason a complete, open surgical set-up, with vascular instruments, should be available in the operating room at the inception of every laparoscopic procedure. When major bleeding occurs during a laparoscopic procedure an aspiration device is inserted and used to suction blood, identify the area of bleeding, and apply pressure to tamponade the bleeding. Inserting a 4 x 4 inch gauze swab through the port may assist in applying tamponading pressure. The assistant holds the tamponading instrument while the surgeon inserts the laparoscope through an appropriate port and directs it against the abdominal or flank wall in the line of the planned opening incision. The scalpel or electrosurgical instrument is then used to incise the skin, subcutaneous tissues and muscles down onto the laparoscope and port. After the appropriate wound is opened the tamponading instrument and gauze will direct the surgeon to the bleeding site. Control can be established with dissection of the vascular structure and ligation or sutured closure of the vessel. It is advisable to obtain an intraoperative vascular surgery consultation when great vessel injury has occurred.
Major vessel injuries are more likely to occur in complex procedures in patients who have undergone previous surgery.30 In experienced hands these injuries need not result in conversion to open surgery. Tamponade with the aspiration device is utilized by the assistant to maintain control of the bleeding site. This maneuver is quite feasible on the vena cava which is usually pliant. The Endostitch (U.S. Surgical Corp., Norwalk, CT) device and the Lapra-Ty (Ethicon Endosurgery Inc., Cincinnati, OH) suture clips should be readily available in the operating room for suture control of large vessels. The appropriate sized Endostitch suture material (i.e. 3-0 or 4-0 polyglactin), in a 7 inch length, is used with a Lapra-Ty clip placed on the distal end of the suture. The clip is dropped into the working port and the Endostitch device is inserted. The Endostitch is used to place the first suture throw just cephalad to the aspirator tip, for a large laceration, or at the center of a small laceration. Additional suture throws are placed to establish hemostasis, as the suture is held snug to the vessel with a grasping forceps by the surgical assistant. Control of the bleeding is obtained with suture using the aspiration device as necessary. At completion of suture closure a second Lapra-Ty clip is placed on the single strand of suture to secure the closure. The adequacy of the vascular closure should be checked by decreasing the retroperitoneal pressure to 5 mm Hg and observing the area for satisfactory hemostasis.
Each kidney receives 12.5% of the total cardiac output. Therefore, incision of the renal parenchyma results in significant and dramatic bleeding. The ability to control this bleeding has been a major limitation to laparoscopic partial nephrectomy and wedge resection of renal tumors. Various cutting and hemostatic modalities have been utilized, or are being evaluated, for performing renal parenchymal incisions. Most reports have described the combination of electrosurgical, pure cutting current, and argon beam coaguation.31,32 The intended line of incision on the exposed renal capsule is marked with the electrocautery. Then the capsule and parenchyma are incised and progressively cut through using the cutting current of the electrosurgical blade or scissors, followed closely by a 10 mm laparoscopic argon beam coagulation probe. Alternatively, the harmonic scalpel which uses high frequency ultrasound vibration of the blade to create tissue cutting and simultaneous coagulation may be used. The raw parenchymal surface is then extensively fulgurated with the argon beam coagulator.
The argon beam coagulator is most effective when used to lightly paint the entire parenchymal surface. Once hemostasis has been achieved, repeated fulguration may induce new bleeding as the deepened eschar sloughs. Additional hemostasis can be established by placing an Avitene plug or patch over the parenchymal surface.
The mechanism of the argon beam coagulator utilizes a high pressure jet of argon gas at 4 L/min applied to clear the parenchymal surface of blood and facilitate coagulation with the electrocautery. A resultant sudden increase in retroperitoneal pressure occurs whenever the argon beam coagulator is used, and this must be released to avoid pulmonary compromising increases in the pressure. Stabilization of the retroperitoneal pressure is usually best achieved by opening one of the port sidearms.
Laboratory and clinical experience with the argon beam coagulator confirms effective coagulation of the renal parenchymal vasculature.32 However, the intrarenal collecting system requires additional closure to eliminate urinary extravasation. A preplaced ureteral catheter can be used to inject indigo carmine dye to identify openings in the collecting system. These are then closed, using an intracorporeal suturing technique, with 2-0 or 3-0 chromic or vicryl suture. An indwelling ureteral stent is usually left in place if transgression of the upper collecting system has occurred. A postoperative intravenous urogram confirming the absence of extravasation determines removal of the ureteral stent usually 2 to 4 weeks postoperatively.
Retroperitoneoscopy reduces the need for retraction of intra-abdominal viscera such as bowel, liver and spleen. However, the surgeon must be cognizant that these structures lay close to the operative site, with only a thin peritoneal reflection separating them from the retroperitoneal space. Extensive and indiscriminate use of electrocautery medial to the kidney increases the risk of thermal injury to the bowel. Retroperitoneoscopy does not provide visualization of the abdominal cavity resulting in delayed recognition of these injuries. Patients with prolonged ileus or postoperative symptoms suggesting peritoneal irritation should be evaluated with computed tomography of the abdomen for potential bowel injury. Open exploration is mandatory and a diverting enterostomy may be necessary for management of bowel perforation. Intraoperative suspicion of a bowel injury dictates conversion to a transperitoneal approach. Small serosal injuries to the bowel may be managed with intracorporeal suturing, or the Endostitch device, and Lapra-Ty suture clips. More extensive bowel wall injury, in the prepared bowel, may necessitate segmental excision and bowel reanastomosis which can be performed by experienced laparoscopists. A consultation with general surgery is recommended.
Technical difficulties during dissection of the kidney may necessitate conversion to an open approach. This most often occurs when there is extensive fibrosis of the retroperitoneal space from previous surgery or inflammation (i.e. xanthogranulomatous pyelonephritis).27 The placement of a ureteral catheter and superstiff guidewire prior to the laparoscopic procedure may facilitate ureteral identification in the retroperitoneum and provide a discrete point from which the renal dissection may be extended. Ureteral identification is particularly important during retroperitoneoscopy as anatomic landmarks are less obvious than during the transperitoneal approach. Large surgical specimens, greater than 150 gm, may be difficult to dissect and entrap due to limited retroperitoneal space. It may be more prudent to use a transperitoneal approach in patients with large kidneys and anticipated extensive retroperitoneal fibrosis.
Laparoscopic dissection or tissue retraction in the retroperitoneum may result in ureteral injury. This occurs more commonly when extensive retroperitoneal fibrosis (i.e. xanthogranulomatous pyelonephritis or previous renal surgery) limits identification of the ureter. When a ureteral injury is suspected the integrity of the ureter can be evaluated by administering intravenous indigo carmine. The site of ureteral injury is identified by the leakage of blue urine. When difficult ureteral or retroperitoneal dissection is anticipated, a preplaced ureteral catheter and superstiff guidewire facilitate dissection and identification of the ureter by movement in the retroperitoneum when the catheter is manipulated at the urethral meatus. In addition, indigo carmine solution may be injected retrograde through the catheter to evaluate the integrity of the ureter or upper collecting system. Ureteral transection or laceration recognized intraoperatively may be laparoscopically repaired using intracorporeal suturing or the EndoStitch device and Lapra-Ty suture clips. An indwelling ureteral stent is inserted for 4 to 6 weeks to assist ureteral healing.
Ureteral or upper collecting system injury, not recognized intraoperatively, may result in a myriad of postoperative symptoms and signs. Postoperative flank pain, unexplained fever (T>38.5oC) or persistent discharge or leakage from a port site should be evaluated with an intravenous pyelogram or abdominal CT scan. Further evaluation of the upper collecting system is best performed via cystoscopy and retrograde pyelogram. Placement of an indwelling ureteral stent may provide definitive therapy. However, the presence of an urinoma or significant upper tract obstruction may necessitate placement of a percutaneous drain or nephrostomy tube. Complete transection or occlusion of the ureter, on retrograde pyelogram, dictates open exploration and direct ureteroureteral anastomosis, reimplantation of the ureter including a psoas hitch or a Boari flap as necessary, transureteroureteral anastomosis or ileotransposition.
The extraperitoneal approach to urologic laparoscopy has several clinical implications, including alteration of the degree of CO2 absorption compared to transperitoneal laparoscopic urologic surgery. Review of the anesthetic records of patients who had undergone laparoscopic renal surgery at Washington University permitted calculated hourly estimates of CO2 expiration (VCO2) during the pre-insufflation period and the first 4 hours of insufflation.33 VCO2 increased with time, although the increase became less pronounced every hour after the first, such that the majority of increase occurred during the first two hours of insufflation. Multiple factorial analysis revealed that the extraperitoneal, as compared to the transperitoneal approach, coupled with the presence of subcutaneous emphysema was strongly and independently associated with a greater increase in VCO2. Pneumothorax, age, sex, operative procedure, use of the pneumodissector, intravenous fluids, urine output, preoperative medical condition, arterial end-tidal CO2 gradient, total insufflation time, use of positive end-expiratory pressure, and obesity were not statistically associated with an increase in VCO2. Pneumothorax or pneumomediastinum were significantly more common during extraperitoneal (37%) than the transperitoneal (3%) laparoscopy. There were five postoperative cardiopulmonary complications, none of which were related to hypercapnia. Carbon dioxide absorption during laparoscopic renal surgery, which is greater than occurs during pelvic laparoscopy, was highest in patients approached through an extraperitoneal route and in those with subcutaneous emphysema. None the less, with aggressive intraoperative pulmonary management there were no sequelae of hypercapnia in any patients in this series. Laparoscopic renal surgery in general is associated with greater CO2 absorption than during laparoscopic pelvic surgery. Pneumothorax and/or pneumomediastinum occur more often during extraperitoneal laparoscopy, but thoracostomy is usually unnecessary in the absence of direct surgical injury. Despite very high levels of CO2 absorption, with aggressive pulmonary management no patients should suffer clinical sequelae of hypercarbia resulting from laparoscopy. Other investigators have reported similar findings.34
Prolonged, increased intra-abdominal pressure during laparoscopic surgery has been associated with oliguria and anuria. At Washington University the effect of increased intra-abdominal and retroperitoneal pressure on urine output and renal function was evaluated in the porcine model.11 Statistically significant decreases in urine output and renal vein flow were associated with intra-abdominal pressures greater than 10 mm Hg. The decrease in urine output was paralleled by the decrease in the renal vein flow and was similar for the retroperitoneal and transperitoneal insufflation in experimental animals. This has also been observed in the clinical setting. Decreased urine output during prolonged intra-abdominal or retroperitoneal pressure greater than 10 mm Hg does not appear to be associated with any long-term functional renal derangement. Neither intraoperative fluid administration nor the use of parenteral dopamine alters the effect of increased intra-abdominal pressure on urine output. Therefore, intraoperative administration of intravenous fluids should be restricted to avoid postoperative complications secondary to intravascular fluid overload such as congestive heart failure or reduced hematocrit.
CLOSURE RELATED COMPLICATIONS
Herniation of omentum or small intestine at a trocar site can occur following laparoscopic renal surgery.6 The risk of this complication would theoretically be reduced using the retroperitoneal approach. However, as Gill and colleagues demonstrated, improper placement of the dilating balloon catheter between muscle layers of the flank can be predisposed to a postoperative flank hernia at the trocar site.6 In addition, avoidance of previous flank surgical scars as trocar sites will limit subsequent hernia formation.
Development of hernias in the early postoperative course may be preceded by prolonged ileus or the development of ileus after an initial period of normal bowel function. There may be abdominal wall tenderness without flank bulging. A CT scan of the abdomen is usually diagnostic and helps to direct surgical intervention which is usually best approached through an open incision. Prosthetic mesh may be indicated to strengthen the repair and closure.
Delayed presentation of a flank hernia following retroperitoneoscopy may occur up to 2 - 3 months postoperatively. These hernias usually occur when an extension of one of the inferior flank port sites has been performed to facilitate the removal of a large surgical specimen not amenable to entrapment in an organ entrapment sack. In our experience the obese or morbidly obese patient (Body Mass Index > 28 ) appears to be at greater risk for this complication.2 The patient will present with a bulge in the flank region which may be associated with pain. These hernias require open repair and incorporation of a prosthetic mesh. In the patient requiring an extension of a port site incision, for specimen removal, a subcostal port site is the better choice for this maneuver.
All retroperitoneal ports should be removed under laparoscopic visualization using a reduced insufflation pressure. This examination will identify small venous structures which may have been temporarily tamponaded by the port. Unrecognized vessel injury in the flank musculature, on port removal, may result in significant flank and retroperitoneal bleeding.
Retroperitoneal pressure should be decreased to 5 mm Hg and the operative sites and each port examined for satisfactory hemostasis. Each port is removed under laparoscopic visualization. It is advisable to change the laparoscope to a 5 mm lens and remove ports of greater than 5 mm first as they are more often associated with muscle or vascular injury. If bleeding is noted at a trocar site, the Carter-Thomason device should be used to place a closing suture.28 The 10 mm or 12 mm conical obturator of the Carter-Thomason device is directed through a port site into the retroperitoneal space under laparoscopic visualization (Figure 2). The conical obturator has two oblique channels which direct the needle-pointed grasper through the fascia and muscle at opposite sides of the port site below skin level. An 0-absorbable suture (36 inches) is grasped in the needle-pointed grasper and directed through one of the obturator channels and positioned in the retroperitoneal space (Figure 2a). The jaws of the grasper are opened and the end of the suture is dropped into the retroperitoneal space. The needle-pointed grasper is removed and re-directed through the opposite obturator channel and into the retroperitoneal space under laparoscopic visualization. The grasper will be on the opposite side from the initial insertion. The jaws of the needle-pointed grasper are used to secure the end of 0-absorbable suture (Figure 2b). It is helpful to place a grasping forceps through a secondary port to facilitate “handing” the suture end to the needle-pointed grasper and reduce the movement of this sharp instrument within the retroperitoneal space. The grasper is withdrawn, with the suture secured in the jaws, creating a through-and-through fascial and muscle closure of the port site (Figure 2c). The obturator is removed and the suture lifted up against the flank tissues. Persistent bleeding on laparoscopic visualization dictates the placement of additional suture. The obturator is replaced at the port site with the directing channels positioned at 90 degrees from the initial placement to guide suture closure through the opposite port quadrants. After placement of the suture, as directed above, the obturator is removed and with laparoscopic confirmation of hemostasis the sutures are tied down securely over the flank fascia. The Carter-Thomason device allows quick and accurate placement of hemostatic closure sutures.
Unrecognized flank wall bleeding may result in hematoma or a decrease in the patient’s hematocrit. A suspected retroperitoneal bleed may be confirmed with CT scan. In most instances, if the patient is hemodynamically stable, these bleeding episodes can be managed expectantly. The retroperitoneal space has the capability of tamponading a small amount of venous oozing. However, hypotension or a significantly decreasing hematocrit (< 24%) is an indication for open exploration, in addition to fluid resuscitation of the patient. Flank wall bleeding is usually self-limiting.
Laparoscopic surgery has gained widespread popularity with associated reduction in postoperative pain and hospital stay and a quicker recovery as compared to open laparotomy for the same surgical procedure. However, as with open surgery, laparoscopy has associated risks and complications which must be recognized and appropriately managed by the surgeon to reduce possible patient morbidity.
Laparoscopy has been associated with a steep learning curve and this is particularly true for laparoscopic renal surgery which is technically demanding.27,35,36 Features of the laparoscopic approach, such as surgical time, physiologic considerations and anatomical limitations of individual patients, may dictate conversion to an open approach for completion of the planned procedure. Conversion should not be regarded as a complication, but rather as good judgment by the surgeon. Greene suggests that there is a “golden period,” which must be recognized by the surgeon, in which conversion to an open procedure reduces the risk of complications and completes the planned procedure expediently.37 Laparoscopic experience improves the surgeon’s ability to recognize the need for conversion and extends the appropriate time in which this decision should be made. To continue laparoscopic surgery in the face of bleeding, equipment problems or restricting tissue exposure increases the chance of misadventure. The judgment decision should dictate conversion for completion of a safe surgical procedure.
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