Complications of Retroperitoneal Exploration

Aram N. Demirjian, M.D.1 and Nita Ahuja, M.D.1

1Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, USA

Address correspondence and reprint requests to:

Nita Ahuja, M.D.

Associate Professor of Surgery

The Johns Hopkins Hospital

1650 Orleans Street, CRB I 342

Baltimore, MD 21231

Telephone: (410) 502-8200

Fax: (410) 502-1958

E-mail: nahuja1@jhmi.edu

Introduction and Anatomy

Surgical complications which arise secondary to exploration of the retroperitoneum are a direct

function of the structures within and their relationship to each other1. Therefore, any discussion

of the potential pitfalls and hazards of operating in the retroperitoneal space must begin with a

thorough review of the anatomy of this region, as well as the various forms of pathology which

arise there. The retroperitoneal space can be divided into three zones: the anterior pararenal

space (APS) which stretches across the midline, two perirenal spaces (one on each side of the

midline), and likewise two posterior pararenal spaces (PPS)2. The APS includes the pancreas,

retroperitoneal portions of the duodenum (2nd, 3rd, 4th), ascending and descending colon, the aorta

and vena cava, lymph nodes (para-aortic, paracaval, aortocaval), lymphatic vessels and fat. The

perirenal spaces contain the kidneys, renal hilar structures, adrenal glands, ureters, lymph nodes,

and fat. Fat is the major component of the PRS. As can be seen in Figure 11, the aforementioned

structures are in close apposition to one another. Any type of pathology arising in these areas

can quickly impinge on neighboring structures, and make surgical manipulation difficult and

possibly dangerous.

Given the diverse array of tissue types – solid organs, blood vessels, lymphatics, fat, nerves,

areolar tissue – a multitude of varying types of pathology is possible. Solid organ tumors such as

pancreatic cancers or renal cell carcinomas, sarcomas, hematoma, blood vessel injury or bowel

injury as a result of trauma, and lymph node involvement secondary to multiple different primary

malignancies can all be impetuses to explore the retroperitoneal space. The goal of this chapter

will be to describe the common complications of retroperitoneal exploration.

Complications can be separated into short-term or acute complications, and long-term or delayed

complications. The occurrence or frequency of adverse events is partly dependent on the type of

surgery being performed, the urgency of that procedure, as well as the surgical approach being

employed. We will consider some of the more common surgical reasons to explore the

retroperitoneal space and consider the attendant complications.

Pancreatic Resection

Pancreatic resections include pancreaticoduodenectomy (PD), distal pancreatectomy (DP), total

pancreatectomy (TP), as well as pancreatic drainage procedures. Given the location of the

pancreas and its intimate association with major vascular structures, bleeding from injury to the

portal vein, superior mesenteric vein or artery, the hepatic artery, the gastroduodenal artery can

easily occur. Various series estimate the risk of bleeding following pancreatic resection to

complicate 5 to 12% of cases3-5. According to one large study from Germany, bleeding

following pancreatic resection of any type occurred with a frequency of 5.7%, and led to the

death of 16% of those patients6. Bleeding after PD can either be an early or late phenomenon.

Early bleeding, defined in the German study as occurring within the first 5 days post-operatively,

is most commonly the result of unrecognized vascular injury, an error in technique (achieving

inadequate hemostasis), or intraluminal gastrointestinal bleeding, e.g. from an anastomotic suture

line. Treatment in this situation may include endoscopy, angiography, reoperation, or some

combination of those modalities. Delayed bleeding can be a devastating complication of

pancreatic surgery. Although the mortality rate for all episodes of post-pancreatectomy bleeding

was 16%, this rose to 47% if the analysis was confined to just the late bleeding. Late bleeding is

defined as occurring after post-operative day 5, and is nearly always associated with a pancreatic

fistula. Most experienced authors advocate an angiographic approach in this setting, however

the chance of requiring reoperation is high.

Another well described complication of retroperitoneal exploration is a chyle leak. This

complication is not specific to surgery of the pancreas, and could be described in any section of

this chapter, but it deserves some words of mention in terms of how it relates to pancreatic

resection. Chyle leak is a well-described phenomenon, but little data existed on the subject as is

relates to pancreatic surgery until a large series from the Johns Hopkins Hospital was reported in

20087. Results collected from more than 3500 pancreatic resections demonstrated an overall

incidence of 1.3%, with the majority of patients having a contained leak as opposed to diffuse

chylous ascites, at a ratio of approximately 2.5:1. Based upon this study, two factors were

identified as significantly enhancing the risk of developing a chyle leak: more extensive lymph

node dissection/harvest as well as a need for vascular resection. The majority of patients were

successfully treated using conservative measures such as total parenteral nutrition (TPN) and

being kept nothing per os (NPO). As could be expected, this management technique was less

often possible in the setting of diffuse chylous ascites, where reintervention was frequently

necessary.

This brings us to the most common complication associated with pancreatic resection, which is a

pancreatic leak or fistula. There is a very wide and disparate range of incidence reported for

pancreatic leak/fistula depending both upon the type of operation (PD vs. DP) and the reported

series. For PD, the rate can range from 5 to 15%, whereas for DP, some papers note the rate to

be as high as 34% (5% again being the bottom of the range)8-14. This complication cannot be

thought of as an all or none entity – there is a wide spectrum of severity which can lead to

different clinical scenarios requiring varying types and levels of intervention. This can range

from minimal interventions such as keeping the patient NPO with total parenteral nutrition

(TPN), to maximal control of the leak using further percutaneously placed drains, to reoperation

for leak control or possibly completion pancreatectomy in the most severe cases (especially

when bleeding is involved). Abscesses can also complicate the post-operative course following

pancreatic resection. This complication is said to occur in 4% to 16% of cases8. A recent

retrospective review of 908 patients from Memorial Sloan Kettering Cancer Center (MSKCC) in

New York revealed 42 “clinically significant” abscesses not otherwise associable with a

pancreatic leak or fistula15. As with pancreatic leaks, such complications range widely in

severity, and may be managed with intravenous antibiotics alone, might require drainage via

radiologically-guided percutaneous catheters, or possibly necessitate operative intervention for

control of more severe infections/intra-abdominal sepsis.

Though operative mortality associated with pancreatic resection has been reduced to below 5%

at most high-volume academic centers in North America, significant morbidity remains a

challenging problem. In an effort to better and more uniformly discuss these complications and

their effects, some groups with large pancreatic surgery experiences have applied a grading

system previously developed by Clavien et al in 1992 (Table)16. This was done by the MSKCC

group to look specifically at pancreatic leaks, fistulae, and abscesses, and they deemed

“clinically significant” to be those complications grade 2 and higher15. As previously mentioned,

this was a review of over 900 patients, and the assessment yielded 158 grade 2 or higher

complications. This group of patients required significant rates of repeat or additional

percutaneous drainage, reoperation, intensive care unit (ICU) need, and extended, complex post-

hospital care, all at significantly greater expense15.

Retroperitoneal Sarcoma Resection

The variety of structures in the retroperitoneum can give rise to a number of different types of

sarcoma. Of all the soft tissue sarcomas, the number originating in the retroperitoneum is

relatively small – only around 15% in the United States17. Symptoms are typically vague and

often appear only after tumors reach a significant size18. The most common types of

retroperitoneal sarcomas are liposarcomas and leiomyosarcomas18. Post-operative complications

following resection of a retroperitoneal sarcoma are dependent on the tumor location and the

extensive nature of the required operation, specifically referring to multi-organ resection. In

order to perform a safe and oncologically sound operation, it may be necessary to undertake

bowel resection, solid organ resection/removal, or vascular resection/reconstruction. In that

setting, any complication associated with a specific procedure or organ is added to the risk of

inadvertent injury to any other structure of the retroperitoneal space. Those complications which

have been noted by larger series, and are specific to the retroperitoneal space include bleeding,

infection/sepsis, anastomotic leak following bowel resection, pancreatic leak (with concomitant

pancreatic resection), lymphatic complications, and motor nerve injury18, 19. The exact rate of

complication associated with resection of retroperitoneal sarcoma is difficult to quantify owing

to the variability inherent to tumors of different sizes and different degrees (if any) of

multivisceral involvement. One study of 65 patients included 5% bleeding, 1 anastomotic leak

(out of 25 performed), 5% “other”, and no infections18. Another larger series (500 patients)

reported a 30-day mortality of 4% with bleeding and widespread infection as the most likely

causes of death when considering factors specific to the retroperitoneal space19. A retrospective

review of 200 primary retroperitoneal sarcomas from the United Kingdom (UK) revealed the

need to resect adjacent intra-abdominal or retroperitoneal organs 63% of the time. Significant

bleeding was the leading cause of morbidity both intra-operatively and post-operatively, and

post-surgical complications necessitated a return to the operating room in 12% of cases20.

The most commonly injured nerve in this situation includes the femoral nerve which can be

involved in or intimately associated with larger retroperitoneal lesions, and damage to which can

cause severe morbidity interfering with ambulation. This nerve can often be exceedingly

difficult to identify, especially in the setting of a bulky lesion. In fact, one group reported the use

of electromyographic (EMG) monitoring to identify the location and track the course of the

femoral nerve as a way to better preserve it21.

Another far less common complication which has been reported in select cases is that of a

duodenocaval fistula. This is a dreaded complication and has a mortality rate of nearly 40%. It

can occur after resection of a retroperitoneal tumor, most often when adjuvant radiation therapy

is employed. Patients present with either sepsis or massive gastrointestinal bleeding in a

majority of cases, and with both symptoms nearly 50% of the time22.

Adrenalectomy

This operation could be included in the following section of the chapter on urologic procedures

based upon the organ’s anatomic location, however owing to its vastly different physiologic

function, it is discussed here separately. Except for larger tumors, adrenalectomy is now

typically performed laparoscopically. The range of complications is very similar to those for

nephrectomy. These include vascular injury, bowel injury, injuries to adjacent organs (liver,

spleen, etc.), pancreatic injury, and diaphragmatic injury23. Vascular injuries are the most likely,

with the adrenal veins being most at-risk, and can complicate as many as 5% of cases24. Injuries

to the bowel and spleen are rare, with bowel injury occurring approximately 1% of the time, and

splenic injury in up to 2.5% of cases23. Diaphragm/pleural injuries are uncommon, but can

present a challenging situation. Given the anatomic location of the adrenal gland (kidney as

well), the posterior portion of the diaphragm can be at risk. Injury in this location can happen

during both open and minimally invasive procedures, though it is typically readily identified

intra-operatively in the open setting. Laparoscopy can provide the confounders of more limited

visualization, along with high intra-abdominal pressure and the possibility of forced insufflating

gas into the thoracic space23. Both surgeon and anesthesiologist must be aware and vigilant in

order to prevent serious consequences. Fortunately, this injury occurs in less than 1% of adrenal

and renal resections23.

Urologic Procedures

Much of the information available regarding complications of retroperitoneal surgery comes

from the urologic literature. In this section, we will consider two procedures whose study has

contributed significantly to the understanding of the dangers of working in a tight anatomical

space.

Nephrectomy

There are multiple factors to consider when discussing renal surgery. These primarily include

the approach (laparoscopic vs. open) and the operation (radical vs. partial nephrectomy).

Laparoscopic radical nephrectomy (LRN) has many applications and has become the standard

for early-stage renal carcinomas. Inadvertent injury to adjacent organs and damage to vascular

structures are the two most frequent categories comprising morbidity associated with this

procedure. Based upon a recent meta-analysis, these occur with frequencies of 4% and 2%,

respectively. Organs most commonly at risk include small or large bowel, the spleen, the

pancreas, and the diaphragm. Bowel injury occurs infrequently, 0.75 to 0.8%, but can be a

devastating complication as it is often unrecognized at the time of surgery, and may present

multiple days into the post-operative course25, 26. Splenic injury has a reported incidence of 1.4%,

and pancreatic injury occurs 0.4% to 2.1% of the time, all during left nephrectomy27, 28. Vascular

injuries typically stem from failure to control the vessels of the renal hilum. Chylous ascites can

also be a complication of LRN, but this is uncommon. Factors which have been found to

contribute to these complications are believed to include surgeon experience, patient obesity,

tumor size/stage, and prior abdominal operations27. Studies have shown no significant

differences in the rate of complications when comparing laparoscopic and open procedures.

When considering partial nephrectomy, the same risks apply as those with LRN, with the added

possibilities of bleeding from the renal parenchyma and urine leak. Urine leak appears to occur

in less than 3% of cases29, 30.

Another uncommon complication of retroperitoneal surgery, though not exclusive to

nephrectomy, is an acquired lumbar hernia. It is most appropriately discussed in this section of

the chapter as it (the incisional type) was first described in the context of that operation in the

early 1950’s31. The anatomic boundaries of the region are the 12th rib (superior), the erector

spinae muscles (medial), the external oblique (lateral), and the iliac crest (inferior)32. With

regard to exploration of the retroperitoneal space, lumbar hernia would most commonly occur as

a consequence of nephrectomy, abdominal aortic aneurysm (AAA) repair via a retroperitoneal

approach, and possibly a retroperitoneal sarcoma resection. Diagnosis may be difficult, owing

mainly to the location of the lumbar triangle, and the hernia can have a multitude of

presentations ranging from no symptoms at all, to pain, to bowel or urinary obstructions. As

lumbar hernias tend to steadily increase in size, most advocate relatively early surgical repair in

order to avoid further complications32.

An extremely rare, but reported complication of laparoscopic nephrectomy is injury to the

common bile duct (CBD). A recent case report described this incident as occurring during a

laparoscopic partial nephrectomy, in the setting of multiple adhesions (due to prior

cholecystectomy) causing bowel to be adherent to the underside of the liver. The injury was

recognized at the time of operation and repaired primarily33. The rarity of this complication is

underscored by the fact that is goes unmentioned in the exhaustive report by Permpongkosol et

al. of complications of laparoscopic urologic surgery34.

Retroperitoneal Lymph Node Dissection

A bulk of the information regarding complications of retroperitoneal surgery is derived from the

study of retroperitoneal lymph node dissection (RPLND), particularly when done for testicular

cancer. This was typically done as an open procedure, but more recently has evolved to

frequently include the laparoscopic approach, which was first introduced in the early 1990’s35.

As in all cases, complications can be classified into two groups: intraoperative and postoperative,

and in this case, one must also consider whether the procedure was performed after

chemotherapy was given. Potential intraoperative complications of laparoscopic RPLND

(LRPLND) include vascular injury, bowel injury, and solid organ injury. Possible postoperative

complications are retrograde ejaculation, chylous ascites, lymphocele, retroperitoneal hematoma,

and nerve injury36. Vascular complications are the most common and occur with a frequency of

2.2% to 20% depending on the series. Additionally, vascular damage is the primary reason

necessitating the conversion to an open procedure. Vessels reported to be most likely involved

include the vena cava, branches of the aorta, renal vessels, lumbar veins gonadal veins36.

Conclusion

Morbidity associated with surgical exploration of the retroperitoneal space is closely tied to how

densely packed this area is. Complications are a function of the different operations performed

in that space, but in all cases, more so than in other areas, adjacent organs are involved or at-risk

One must anticipate the need for multivisceral complications – both planned and unplanned –

and careful counseling of the patient is needed to discuss potential complications and the

potentially unpredictable and various nature of those complications. Given the wide range of

possible complications, it stands to reason that high-volume surgeons, with a wealth of

experience in the retroperitoneal space, will likely have lower operative risk.

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Figure 11