There have been numerous studies evaluating other potential serum and urinary markers of appendicitis, including but not limited to inflammatory cytokines such as serum interleukin-6, interleukin-8, and tumor necrosis factor alpha; serum neutrophil proteins such as lactoferrin and calprotectin; and urinary markers such as leucine-rich α-2-glycoprotein. None of these have been shown to be superior to traditional markers of inflammation in a prospective trial.

There are several clinical scoring systems that have been used in the diagnosis of acute appendicitis. The most common is the Alvarado scoring system published in 1986, also referred to as MANTRELS based on the mnemonic for remembering the combination of eight signs and symptoms (Table 71-2).¹³ The score ranges from 0 to 10; a patient with a score of 5 or 6 is typically observed, whereas a patient with a score of 7 or greater should undergo operation.¹³ Since then, there have been several studies evaluating the diagnostic accuracy of the Alvarado score, as well as modified versions of the Alvarado score such as the Pediatric Appendicitis Score,¹⁴ and other scores such as the Kharbanda¹⁵ and Lintula¹⁶ scores. In general, these clinical scoring systems have better predictive ability than individual symptoms or signs alone. However, these scoring systems do not have sufficient discriminatory or predictive ability to routinely be used alone to diagnose appendicitis. They have been used to determine the need for further radiologic studies¹⁷ or as a guide for dictating clinical management.¹⁸

RADIOLOGIC IMAGING

At one time, surgical clinical acumen was graded on the ability to diagnose appendicitis on physical examination, but currently, more and more patients are diagnosed using imaging studies. Population-based analyses of regional administrative data in the 1980s and 1990s demonstrated a significant increase in the use of ultrasound (US) and computed tomography (CT). One would hope that this increase in imaging would lead to a decrease in the number of ruptured or negative appendectomies, but that is not the case.^19,20 On one hand, imaging may be helpful in the evaluation of patients with abdominal pain for excluding other diagnoses or for preventing unnecessary operations.¹⁹ On the other hand, imaging could potentially delay operative intervention, and in the case of CT, radiologic imaging exposes patients to the risks of ionizing radiation. Ultrasonography does not expose patients to ionizing radiation but is more operator dependent. In a meta-analysis of US and CT in children and adults, both US and CT were highly specific (93% to 95%) in children and adults, whereas CT was more sensitive than US.²¹

3 The Surgical Infection Society and Infectious Disease Society of America guidelines recommend helical CT with IV contrast as the test of choice when imaging is indicated in patients with suspected appendicitis. There is moderate supporting evidence for this from well-designed but nonrandomized trials.^7,22 A recent meta-analysis evaluated the effect of CT on negative appendectomies, rates of perforation, and time to surgery in patients with acute right lower-quadrant pain.²³ The meta-analysis concluded that preoperative CT resulted in a reduced rate of negative appendectomies but an increase in time to surgery, although there was no increase in rate of perforation. There are some data to support the use of noncontrast CT of the abdomen in adults. The test had reasonably high sensitivity and specificity for clinical decision making (93% and 96%, respectively).²⁴

There have been only a few randomized trials evaluating different strategies incorporating radiologic imaging on clinical outcomes. Only one trial found a difference in accuracy. Lee and colleagues compared a strategy of mandatory or selective CT scanning in patients with suspected appendicitis and less than 72 hours of symptoms. They found there were fewer negative appendectomies and perforations in the group undergoing mandatory scans.²⁵ Another trial reported that CT scanning changed management in only 26% of patients.²⁶

Clearly, CT can be useful for cases without clear indications for surgery.

IDENTIFYING PERFORATED APPENDICITIS PREOPERATIVELY

Distinguishing whether or not a patient is likely to have perforated or nonperforated appendicitis preoperatively may be helpful in terms of counseling the patient about alternatives for management (i.e., early vs. delayed appendectomy), risk for complications, and the expected postoperative course. A recent meta-analysis identified four studies that presented data for perforated appendicitis. Based on these studies, high values of laboratory markers of inflammation such as a WBC and granulocyte count and the CRP level were relatively strong predictors of perforated appendicitis, whereas low values were relatively strong predictors of not having perforated appendicitis.⁸ A combination of clinical finding and laboratory values can help identify ruptured appendicitis preoperatively by developing a scoring system for children based on five variables, including components of history, physical examination, laboratory values, and CT findings.²⁷ When the scoring system was applied to the study patient population, it increased the specificity of the pediatric surgeon’s preoperative assessment from 83% to 98%.²⁷

FUTURE DIRECTIONS IN DIAGNOSIS

Research is ongoing to identify accurate, efficient, and cost-effective methods of diagnosis. Advances have included using molecular techniques for profiling gene and protein expression to identify novel markers for appendicitis.^28–30 Imaging alternatives to CT scans such as bedside surgeon-performed US,³¹ magnetic resonance imaging,³² or low-radiation CT scanning³³ are being investigated in terms of their diagnostic accuracy and their potential to reduce exposure to radiation. Another avenue of investigation is the use of machine learning and advanced statistical models for informing decision making.³⁴ As advances in technology and diagnostic strategies are made, any improvements in accuracy must be balanced against the proven utility of bedside clinical evaluation as well as costs and potential harms.

MANAGEMENT

Background for Nonoperative Management for Acute Uncomplicated Appendicitis

Appendectomy for acute appendicitis is one of the most common surgical procedures performed worldwide (Fig. 71-1). In the United States, appendectomy incurs considerable indirect costs resulting from time lost from work, school, or usual activities after the procedure.³⁵ The individual lifetime risk of appendicitis is 8.6% for men and 6.7% for women.³⁶ Uncomplicated acute appendicitis is considered almost universally to be an indication for an appendectomy. In 1894, open appendectomy was accepted as the treatment standard, because it saved lives, and since that time, the dictum that surgical removal of the appendix is necessary has been largely unchallenged.³⁷ All surgeons are taught that appendicitis untreated will march on and eventually perforate which puts the patient’s recovery in question. Thus, early surgical exploration and appendectomy is advocated for source control. However, appendectomy for nonperforated appendicitis is not without associated harm. The long-term risk of small bowel obstruction is estimated at 1.3% at 30 years after appendectomy.³⁸ In addition, the “negative” appendectomy rate ranges from 10% to 20%, and remains unchanged despite the widespread use of CT.^39–41

Meanwhile, nonoperative management with antibiotics has been established as the treatment for various intra-abdominal infections such as uncomplicated diverticulitis, salpingitis, and neonatal enterocolitis.⁴² It is surprising that nonoperative management of uncomplicated acute appendicitis remains largely unexplored despite evidence that it often resolves, either spontaneously or with antibiotic therapy, and has been shown by limited studies to have outcomes equivalent to those of appendectomy.^43,44 Accordingly, it may be reasonable to call into question the assumptions and “evidence” that have supported routine appendectomy for this condition.

Spontaneous resolution of appendiceal inflammation does occur, although its frequency is unknown. Presumably, increasing intraluminal pressure dislodges the obstructing material back into the cecum, thereby relieving the distention and inflammatory process. Evidence of previous inflammation may be recognized subsequently as a fibrotic, kinked, or adhesed appendix when viewed at a future operation. In 1 series of 1,000 patients with appendicitis, 9% reported having had a similar clinical illness in the past and 4% reported more than one previous attack.⁴⁵

Widespread CT scan utilization for the diagnosis of appendicitis has resulted in a significant increase in the number of CT scans performed annually.⁴⁶ This has led to several interesting observations regarding the possibility of spontaneous resolution of appendicitis from several centers. Inclusion of a CT scan result in the Alvarado score has been shown to increase the rate of appendectomy. When classified as having a low likelihood of appendicitis (Alvarado score ≤4), patients who underwent a CT scan had an appendectomy rate of 48%.⁴⁶ In contrast, those with an Alvarado score ≤4 who did not undergo a CT scan had an appendectomy rate of only 12% suggesting that some percentage of the population resolved spontaneously.

Decadt and colleagues made a comparable observation for those patients who presented with nonspecific abdominal pain.⁴⁷ The investigators used diagnostic laparoscopy instead of CT scan in the management of patients with nonspecific abdominal pain. Patients were randomized to either (1) diagnostic laparoscopy or (2) nonoperative management (with operative intervention if peritonitis developed). The appendectomy rate was 39% for those randomized to diagnostic laparoscopy and 13% for those managed nonoperatively. These indirect findings and evidence are suggestive that uncomplicated, acute appendicitis may be initially managed nonoperatively.

Nonoperative Management of Acute Appendicitis

To date, there have been few randomized studies of nonoperative versus operative therapy for acute appendicitis, and none have been conducted in the United States. Several reports have appeared in the literature over the last half decade describing nonoperative management of acute, uncomplicated appendicitis.^18,48–50

The trial that has received the most attention was conducted in Sweden.⁴⁸ All patients older than 18 years with presumed appendicitis diagnosed by the physician based on clinical history, laboratory tests, US, CT, and physical examination were included. A total of 369 consecutive patients were randomized to antibiotic treatment or surgery. Study patients received intravenous (IV) antibiotics (cefotaxime 1 g twice and metronidazole 1.5 g once) for at least 24 hours. During this time patients received IV fluids with no oral intake. Patients whose clinical status had improved the following morning were discharged to continue with oral antibiotics (ciprofloxacin 500 mg twice per day and metronidazole 400 mg 3 times per day) for a total of 10 days. In patients whose clinical condition had not improved, IV treatment was prolonged.

There were 202 patients in the study group (antibiotics) and 167 patients in the control group (appendectomy). In the study group, 106 (52.5%) completed the intended antibiotic treatment, and 154 (92.2%) in the control group underwent an appendectomy. Of 108 patients who initially improved without surgery, 15 (13.9%) had recurrent appendicitis at a median follow-up time of 1 year. One-third of recurrences appeared within 10 days following discharge from the hospital. Of the 15 patients with recurrence, 12 had surgery (4 patients had gangrenous or perforated appendicitis and 1 patient underwent ileocecal resection) and 3 had a second round of antibiotic treatment with success.

Efficacy in the study group according to intention to treat was 48.0% (97 of 202). Eleven of 119 (9.2%) patients who primarily received antibiotics had an appendectomy owing to clinical progression. The preoperative characteristics of these patients were similar to those of the patients who fulfilled the antibiotic treatment. Of 250 surgically explored patients, 223 (89.2%) had appendicitis. Primary treatment efficacy was 90.8% for antibiotic therapy compared to 89.2% for surgical exploration analyzed per protocol. Major complications and total hospital cost for the primary admission were both lower in the antibiotic treatment group. This study shows that nonoperative management is an option in properly selected patients.

One of the largest retrospective series reporting nonoperative management of appendicitis comes from Japan.⁵¹ Shindoh and colleagues reviewed their institutional experience with nonoperative management of appendicitis; in this report 367 patients met inclusion criteria (right lower-quadrant pain, WBC >9,000 or CRP >1.0 mg/dL). The authors describe the following three study groups: (1) initial operation or appendectomy, (2) nonoperative group, and (3) initial nonoperative group converted to surgery (failure). In the nonoperative groups, patients received antibiotics and were evaluated 24 hours later. If the physical examination or laboratory parameters worsened, surgical management was considered. In this cohort, 143 (39%) underwent initial operation (group 1), whereas 224 (61%) were managed with initial antibiotic therapy. In the initial nonoperative group, 91 patients did not respond to antibiotics and underwent appendectomy. Factors predictive of failure included CRP (odds ratio [OR] 5.5, 95% CI: 1.94 to 17.29) and the presence of an appendicolith (OR 4.7, 95% CI: 1.15 to 24.46). Of note, in this study recurrence of appendicitis was observed in 4.7% of patients initially managed nonoperatively.

One of the inherent difficulties and biases in conducting a well-planned randomized clinical trial, centers on pathologic confirmation of appendicitis. On one hand, for those patients with “suspected” appendicitis who receive antibiotics only, treatment successes may cause one to consider the underlying diagnosis (“is it really appendicitis?”). On the other hand, the number of patients who undergo a negative appendectomy is not zero and exposure of these patients to surgical risks and complications is a valid concern. The report by Hansson and colleagues demonstrated a threefold increased rate of complications in the appendectomy group when compared to the nonoperative, antibiotic only group.⁴⁸

4 The data presented are suggestive that in selected patients with acute, uncomplicated appendicitis, antibiotic treatment seems to be an appropriate alternative to appendectomy. Multivariate analysis of patient characteristics failed to demonstrate any logistic model for inclusion or rejection of patients for the specified treatments. A few of these studies have found that presence of the fecaliths is predictive of failure. Further studies are needed to create informed multivariate models that adjust for all of the important clinical covariates. Therefore, most patients older than 18 years without obvious signs of intra-abdominal perforation can be offered antibiotic treatment as first-line therapy. Clinical progression and surgical judgment may then determine whether there is a real need for surgical exploration. The benefit would be a significantly reduced frequency of major complications related to surgery, and potentially reduced costs.

Management of Complicated Appendicitis

Of the 11 of 10,000 people in the United States who will develop acute appendicitis over their lifetime,⁵ an estimated 2% to 6% of patients will present with an appendiceal mass, either in the form of an inflammatory phlegmon or abscess.⁵² The optimal management of these cases remains controversial. There is no consensus in the surgical literature on whether to proceed immediately with appendectomy or initial nonoperative management in this setting of complicated appendicitis. Another dilemma in the management of appendicitis initially managed conservatively with antibiotics is whether or not to perform an appendectomy at a later date (interval appendectomy). The data are disparate regarding actual recurrence rates of appendicitis following nonoperative management, but they are commonly reported between 5% and 20%.^53–55 In addition to recurrent appendicitis, a clinical concern in older patients who present with a cecal phlegmon is malignancy. In these cases, interval appendectomy allows the correct pathologic diagnosis to be made.⁵⁶ The effect of these management decisions on duration of hospital stay, number of interventions, healthcare costs, and overall patient satisfaction must be considered.

Appendiceal Abscess

Appendiceal abscess is commonly associated with delayed presentation, fever, leukocytosis, and a palpable mass in the right lower quadrant (Fig. 71-2). The diagnosis is confirmed with CT or US. Management of these patients remains controversial. The traditional nonsurgical approach consists of percutaneous drainage and IV antibiotics, with or without interval appendectomy. Others suggest immediate appendectomy and surgical drainage of the abscess. The evidence supporting both approaches is weak, as most studies are retrospective and often combine patients with appendiceal abscess and phlegmon into a single cohort called “appendiceal mass.” Several meta-analyses have been performed to try to identify differences between the two treatment strategies. Andersson and Petzold performed a meta-analysis on 19 retrospective studies from 1969 to 2005. The limitation of this study is the lack of uniform definition of appendiceal abscess and phlegmon. Nevertheless, the meta-analysis revealed that nonsurgical treatment failed in 7.6% of patients (CI: 3.2 to 12.0). Immediate appendectomy is associated with a higher morbidity with an OR of 3.3 (CI: 1.9 to 5.6). Based on these findings, the authors recommended nonsurgical management of patients with appendiceal abscess.⁵³ Similar conclusions were reached by Simillis and colleagues, who performed a meta-analysis of 16 retrospective studies and 1 nonrandomized prospective study from 1969 to 2007, comparing immediate appendectomy (725 patients) versus nonsurgical treatment (847 patients).⁵⁷ Immediate appendectomy is associated with greater incidence of ileus or bowel obstruction, abdominal or pelvic abscess, and wound infection compared to nonsurgical treatment. There was no difference in the overall duration of hospitalization, but the immediate appendectomy group required more reoperations. The higher rate of complications associated with immediate appendectomy has been attributed to greater inflammatory response to surgery in the setting of infection, as well as the technical difficulty with inflamed tissue. Most of the studies analyzed in these meta-analyses utilized open appendectomy techniques. The potential disadvantages of early operation may be mitigated by the laparoscopic techniques. Laparoscopic appendectomy results in less local inflammation due to better visualization and instrumentation.⁵⁸

St. Peter and colleagues conducted a prospective randomized trial comparing immediate laparoscopic appendectomy to nonsurgical treatment in 40 pediatric patients presenting with appendiceal abscess.⁵⁹ Immediate laparoscopic appendectomy tends toward longer operative time (61 minutes vs. 42 minutes) compared with interval laparoscopic appendectomy performed at 10 weeks from initial presentation. The immediate appendectomy group had fewer healthcare visits and few CT scans. However, there was no difference in recurrent abscess rate, total length of hospitalization, or total charges. They concluded that immediate laparoscopic appendectomy is as safe as nonsurgical management. The safety of immediate laparoscopic appendectomy for appendiceal abscess is supported by several other retrospective or uncontrolled studies.^60–63 The infectious complications of immediate appendectomy can be reduced by improved laparoscopic techniques, such as use of extraction bag, endostaplers rather than endoloops, and limited irrigation to avoid bacterial contamination.^64,65

Appendiceal Phlegmon

The management of acute appendicitis complicated by an appendiceal phlegmon typically involves 1 of 3 treatment strategies (Fig. 71-3). The first, and most commonly accepted, is initial treatment with broad spectrum antibiotics and IV fluids until the acute inflammation subsides; appendectomy is then performed on an interval basis. Another strategy involves appendectomy upon initial presentation. Finally, following resolution of the acute inflammation with broad spectrum antibiotics, the patient is managed expectantly without interval appendectomy. Prospective data comparing these strategies are sparse, with most systematic reviews drawing heavily upon retrospective data.

At present, there is no agreed upon approach for the management of an appendiceal phlegmon. A recently published survey of a group of general surgeons in England found that 75% still favor interval appendectomy following resolution of symptoms.⁶⁶ Proponents for interval appendectomy state that removing the appendix is a technically easier operation once the acute inflammation subsides, potentially avoiding inadvertent injury to adjacent loops of involved bowel, as well as extended resection of the cecum or ascending colon.⁵⁶ Although the risk of recurrent appendicitis remains small after successful nonoperative treatment of an appendiceal phlegmon, proponents of interval appendectomy state that the risk of interval appendectomy is also small and eliminates the possibility of recurrent appendicitis.⁵⁴ In a recent systematic review published by Hall and colleagues, 127 children were managed without planned interval appendectomy.⁶⁷ The incidence of recurrent appendicitis ranged from 0% to 42% in the three studies included in the review, with an overall risk of 20.5% (95% CI: 14.3 to 28.4).

The complication rates following interval appendectomy were also published in this review, with an overall incidence of 3.4% (95% CI: 2.2 to 5.1). The authors concluded that the likelihood of recurrent appendicitis, as well as the risk of complication after interval appendectomy, are both sufficiently low that the decision to proceed with interval appendectomy is typically based on clinical criteria.

Interval Appendectomy

Interval appendectomy provides a tissue diagnosis when diagnostic uncertainty exists. This is particularly important in adults because the differential diagnosis of an inflammatory mass in the right lower quadrant can be quite extensive, with neoplastic etiologies of particular concern. In a systematic review and meta-analysis, 2,771 included patients were initially treated nonoperatively for an appendiceal phlegmon or abscess.⁵³ On follow-up, 31 patients were found to have a malignant diagnosis. In patients younger than 40 years with an appendiceal mass, only 4 were found to have a malignant diagnosis on follow-up: 2 children had carcinoid of the appendix, a 26-year-old woman presented with an ovarian malignancy, and a 25–year-old man presented with metastatic gastric cancer. The overall estimate of a malignant diagnosis was 1.2% (95% CI: 0.6% to 1.7%), with an incidence of 0.2% (95% CI: 0.0% to 0.05%) in children. Inflammatory bowel disease was established as a diagnosis during follow-up in 0.7% of patients (95% CI: 0.2% to 11.9%), with a higher incidence again seen in adults. Although primarily retrospective, these data underscore the need for follow-up, either with CT scan or colonoscopy, after successful treatment of an appendiceal phlegmon in adults.⁵³

The presence of an appendicolith associated with an appendiceal phlegmon deserves special mention, as its presence has been used as a guide to proceed with interval appendectomy following successful nonoperative management. A retrospective cohort study reviewed the outcomes of 96 pediatric patients with appendicitis who presented with either an inflammatory mass or phlegmon, and were initially managed nonoperatively by the staff surgeon.⁶⁸ Six patients who failed initial nonoperative management underwent appendectomy and were excluded. Forty-one patients were scheduled for elective appendectomy by their surgeon and were also excluded from analysis. The remaining patients were included in the study and their outcomes over a 2-year period were reported. Of these, 37% had an appendicolith and 63% did not. The overall recurrence rate for appendicitis was 42%; in patients with an appendicolith, the recurrence rate was 72% compared to 26% in patients without an appendicolith (relative risk of 2.8 in patients with an appendicolith). The authors concluded that the presence of an appendicolith predicts failure of nonoperative management of periappendiceal phlegmon or abscess. It is important to note that the overall recurrence rate of appendicitis in this study is higher than what is typically reported elsewhere in the literature, and this may influence the true effect of an appendicolith on failure of nonoperative management.

Unfortunately, there are no data from a randomized, prospective trial evaluating whether or not the presence of an appendicolith is predictive of failure of initial nonoperative management of ruptured appendicitis with phlegmon or abscess. As such, any conclusions from this study should be viewed as hypothesis-generating for a future randomized controlled trial.

In deciding whether or not to proceed with routine interval appendectomy following successful nonoperative management of an appendiceal phlegmon or abscess, the effect of cost must also be considered.⁶⁹ Even with a high probability of recurrent appendicitis (assumed to be 40%), financial analysis does not favor elective interval appendectomy.

A more robust randomized trial looking at the return to normal activity examined 131 total patients enrolled: 64 receiving initial appendectomy, and 67 were assigned to interval appendectomy.⁷⁰ In the primary appendectomy group, time to normal activity was 13.8 versus 19.4 days in the interval appendectomy group (P < 0.001). Of note, the relative risk of any adverse event associated with interval appendectomy was 1.86; specific outcomes measured included intra-abdominal abscess, small-bowel obstruction, unplanned readmission, and recurrent appendicitis, and these were all seen with higher frequency in the interval appendectomy group. The authors conclude that early appendectomy significantly reduced the time away from normal activity and showed a significantly lower adverse event rate.

5 The optimal management strategy of an appendiceal phlegmon or abscess remains elusive as most recommendations are based on retrospective data, but recent randomized trials in children indicate that early appendectomy results in faster return to normal activity with favorable complication rates when compared to interval appendectomy.⁷⁰ Performing an interval appendectomy following successful nonoperative management with antibiotics and percutaneous drainage, as needed, has yet to be evaluated in a randomized trial. Higher-quality evidence from prospective, randomized trials will help surgeons decide whether or not interval appendectomy in the setting of an appendicolith is appropriate.

SURGICAL OPTIONS FOR ACUTE APPENDICITIS

Laparoscopic versus Open Appendectomy

The open appendectomy was initially described by McBurney in 1894, and has remained relatively unchanged since its introduction. In 1983, Semm described a laparoscopic approach for removing the appendix, advocating the advantages of laparoscopic surgery for one of the most frequently performed surgical procedures.⁷¹ Since open appendectomy also typically involves a small incision, short hospital stay, rapid return to normal activity, and low postoperative morbidity, demonstrating clear superiority of one approach over the other has been elusive. Although many randomized control trials comparing open versus laparoscopic appendectomy have been performed, many contain methodologic flaws, including inadequate allocation concealment, lack of reporting of randomization method, failure of adequate blinding, lack of analysis by intention-to-treat, and incomplete follow-up data.⁷² That being said, these randomized trials, as well as systematic reviews and meta-analyses of these studies, have provided a great deal of insight into the specific benefits and drawbacks of each approach. In deciding between a laparoscopic and open approach, specific issues that must be considered include learning curve, operative time, associated morbidity, cost, pain, cosmesis, hospital length of stay, and time to return to normal activity. Unfortunately, measures vary across studies and conclusions have been inconsistent.

A large retrospective review of prospectively acquired data, compared outcomes of laparoscopic versus open appendectomy in 222 hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) was conducted by Ingraham and colleagues.⁷³ The analysis of 30-day outcomes following laparoscopic and open appendectomy showed overall morbidity, serious morbidity, surgical site infection, and serious morbidity or mortality to be higher in patients undergoing open appendectomy, although these complications were generally low in both groups. A Cochrane review of 67 trials comparing laparoscopic and open appendectomy was updated in 2010.⁷⁴ Of these studies, the vast majority (56) were conducted in adults. Outcomes assessed by the included trials most frequently included operating time, complication rates, hospital stay, pain, and return to normal activity.

6 Although a variety of complications were evaluated, due to inconsistencies in the definition and reporting of these complications, the authors only examined two specific complications in their analysis: wound infection and intra-abdominal abscess. Following laparoscopic appendectomy, wound infections were approximately one-half as likely when compared to open appendectomy (OR 0.43; 95% CI: 0.34 to 0.54). Conversely, laparoscopic appendectomy was associated with a nearly threefold increase in the likelihood of intra-abdominal abscess when compared to an open technique (OR 1.77; 95% CI: 1.14 to 2.76). Operative time was 10 minutes longer for laparoscopic appendectomy (95% CI: 6 to 15), but this difference has been decreasing in recently published trials. Laparoscopic appendectomy was also associated with lower postoperative pain, shorter hospital stay (1.1 days), and faster return to normal activity (5 days), although these results are highly heterogeneous and further study is warranted. Hospital and operational costs are higher with laparoscopic appendectomy, but again, these results are strongly heterogeneous. The authors concluded that laparoscopic appendectomy confers many benefits over open appendectomy, and should be strongly considered as the preferred approach where surgical expertise is appropriate and equipment is available and affordable.

The question of whether or not appendectomy should be performed via an open or laparoscopic technique has been inherently difficult to answer because both approaches offer similar advantages, namely, a small incision, low incidence of complications, a short hospital stay, and rapid return to normal activity. Newer studies would favor laparoscopic approaches but the answer is still not definitive. Ultimately the surgical approach remains up to the surgeon. Well-trained surgeons should be facile in both approaches should the need arise.

Single-Incision (Single-Port) Laparoscopic (SILS) Appendectomy

In the evolving era of “scarless surgery,” SILS has been utilized for appendectomy. A single-incision laparoscopic-assisted appendectomy for acute appendicitis was first reported in adult patients in 1992.⁷⁵ Soon thereafter, this surgical approach began to be reported in children, with the first reports utilizing a single umbilical incision with a laparoscopic-assisted appendectomy, in which the appendectomy was performed after exteriorization through the umbilical incision.⁷⁶ Since then, several techniques under the auspices of SILS have been utilized including natural orifice transluminal endoscopic surgery and many variations of single-incision techniques.^77–80 The touted advantages of the SILS approach to appendectomy are similar to general laparoscopy compared to open operations, including less pain, faster recovery, and better cosmesis. However, critics countered these with concerns about increased costs, longer operation times, and higher complication rates.⁸¹

In adult studies comparing SILS with conventional three-port laparoscopic appendectomy, advantages in cosmetic outcomes were at the cost of longer operation times and substantial early postoperative pain.⁸² SILS is even more popular in children without significant data that show a benefit. Oltmann and colleagues⁸³ reported that SILS with appendectomy is feasible and safe in the pediatric population. Although operating times were longer than the conventional three-port laparoscopic appendectomy, the authors suggested these should improve with better instrumentation and experience. St. Peter and colleagues⁸⁴ reported on the only randomized control trial comparing SILS-assisted appendectomy to conventional three-port laparoscopic appendectomy in 160 children with nonperforated acute appendicitis. Utilizing an extracorporeal appendectomy, there was a nonsignificant difference in wound infection rates of 3.3% for SILS patients compared to 1.7% for conventional laparoscopy. Although there was a statistically significant difference in operative time between the two approaches, the SILS technique was only 5.4 minutes longer (29.8 ± 11.6 vs. 35.2 ± 14.5 minutes). The investigators suggested that the difference was not clinically relevant and both techniques had comparable outcomes.

Operative Approach in Complicated Appendicitis

Clinical evidence that supports the laparoscopic approach for complicated (perforated or intra-abdominal abscess) appendicitis remains controversial. The concern over greater incidence of intra-abdominal abscess following the laparoscopic approach was reported in some studies^85–87 but not supported by others.^88,89 Due to the increased morbidity associated with complicated disease, some surgeons have opted for an initial nonoperative approach.^70,84,90 Using nonoperative treatment for complicated appendicitis followed by interval appendectomy obviates the need to manage the inflammatory environment in the acute stage. Such a strategy has been shown to be successful in treating most of the cases of complicated appendicitis with shorter hospitalization, lower charges, and lower morbidity.^91,92

Outpatient Appendectomy

Traditionally, patients are hospitalized for 24 hours after laparoscopic appendectomy. As we move toward laparoscopic appendectomy becoming a new standard, the question has arisen if this surgery can be done as an outpatient operation. Although this strategy has been advanced in many elective abdominal procedures – laparoscopic cholecystectomy,⁹³ gastric bypass,⁹⁴ and incisional hernia repair,⁹⁵ for example – surgeons remain hesitant to discharge patients on the day of emergency surgery, particularly one with an infectious etiology. As recently as 2004, the average length of stay for laparoscopic appendectomy was 2.06 days.⁹⁶

Most protocols in the literature describe discharge after a set of criteria has been reached. Utilizing these protocols it has been shown that discharge can occur as soon as 171 minutes after completion of the surgery.⁹⁷ This is true regardless of the time of day the surgery was completed. In the largest published adult series, 55% of the patients were discharged between the hours of 6 PM and 6 AM.⁹⁷ Other studies confirm that a protocol for outpatient appendectomy can be successful for early same day discharge.^98,99 In a study of 179 children 158 were targeted for same day discharge. Twenty-one patients were excluded due to findings of perforated or gangrenous appendicitis. One hundred and twenty six (80%) were discharged the same day as surgery with exceptions being made for social issues (too late at night or families unwilling to leave).¹⁰⁰

The studies to date, have been unable to show a difference in morbidity in the groups when comparing immediate discharge to patients who are admitted.^96,97,99,101 In the largest of the studies on the topic postoperative complications occurred in 2.4% of outpatients and 11.7% per cent of inpatients (P = 0.16). Complications included superficial wound infections, urinary retention, urinary tract infection, intra-abdominal bleeding, pneumonia, and infected hematoma. Based upon the data, the authors concluded that outpatient laparoscopic appendectomy can be performed safely in selected patients.⁹⁸

7 Certainly from an economic standpoint, an argument could be made for this transition to outpatient surgery for uncomplicated appendicitis. Length of stay following laparoscopic appendectomy for uncomplicated appendicitis ranges from 1.6 days to 2.1 days.¹⁰² If an outpatient protocol were applied universally, it could result in annual healthcare savings of $920 million. Even a more conservative estimate done in Canada comparing outpatient appendectomies to same day discharges showed a cost saving of $323 Canadian dollars per patient.⁹⁹

APPENDICEAL NEOPLASMS

8, 9 Approximately 1% of all appendectomy specimens will contain a neoplasm.¹⁰³ The most common tumors are carcinoid, benign mucoceles, and mucinous carcinoma. Rare tumors of the appendix include adenoma, adenocarcinoid, lymphoma, and GI stromal tumors. Appendiceal cancer is a rare disease, yet its incidence in the reported literature varies depending on the histologic types included in the classification of appendiceal malignancies. Historic evidence suggests that appendiceal primaries are diagnosed in approximately 1% of all appendectomy specimens.^103–105 In a SEER database retrospective analysis that excluded low-grade carcinoid tumors, the annual age-adjusted incidence of appendiceal primaries was 0.12 cases per 1,000,000 of population. Appendiceal adenocarcinoma represented 66.5% of these patients.¹⁰⁶ Extrapolating from the SEER data, the annual incidence of the appendiceal adenocarcinoma in the country should be around 300 to 400 cases, although estimates up to 2,000 cases annually in the United States have been made. This incidence approximates the estimate that the appendix represents approximately 1% of the mucosal surface of the colon, with 137,000 cases of colorectal carcinoma in the United States encountered annually.¹⁰⁷ The rate of appendiceal neoplasms seems to be increasing.

There are no reliable early symptoms of appendiceal cancer, which, in part, explains why the majority of these patients are diagnosed incidentally during surgical exploration or late when peritoneal or systemic dissemination has already occurred. The rarity of appendiceal neoplasms makes screening programs unrealistic, and they are found by colonoscopy in <10% of cases.¹⁰⁸

The treatment of appendiceal neoplasms depends upon type, stage, and medical comorbidities; not all appendiceal tumors demand the same therapy, operative or otherwise. Interestingly, appendiceal adenocarcinomas are associated with secondary tumors in up to 35% of patients, most often involving other areas of the GI tract.¹⁰⁹

Mucoceles

Mucoceles of the appendix refer to a distended mucin-filled organ, which can be due to either benign (cystadenoma) or malignant (cystadenocarcioma) disease (Fig. 71-4). Such mucoceles are due to an obstructed appendiceal lumen, leading to a large mucin-filled structure, often with calcification in the wall. Such lesions can be readily diagnosed by CT scans, and are often incidental findings. A simple appendectomy is curative for benign cystadenomas. Resection should be done with great care so as not to rupture the lesion, which can lead to dissemination. With rupture, whether of a histologically benign or even more commonly with a malignant cystadenocarcinoma, peritoneal tumor implantation can occur, leading to mucinous ascites, and a condition known as pseudomyxoma peritonei (PMP, see below). The presence of epithelial cells in the mucin extruded from the mucocele at the time of rupture greatly increases the likelihood of recurrence. Due to the potential for malignancy, and possible sequellae of rupture (spontaneous or iatrogenic), appendectomy should be performed in otherwise healthy patients.

Appendiceal Adenocarcinoma

Appendiceal adenocarcinoma typically presents either with symptoms suggestive of appendicitis or symptoms related to peritoneal dissemination. CT or MRI imaging is preferred and PET imaging is of little value in these cases.^110–113 Appendiceal adenocarcinoma represents an unusual neoplasm, which has several variants. Mucinous appendiceal carcinoma is the most common, with colonic type or the signet-ring variant being less common, and associated with poorer outcomes.¹¹⁴ Appendiceal carcinomas are now more common than carcinoid (neuroendocrine) tumors. The appendiceal carcinomas are further subdivided into low- and high-grade lesions.^115,116 Low-grade lesions (sometimes also known as disseminated peritoneal mucinous tumors) have more than double the long-term survival rate of high-grade lesions. Signet-ring cells are associated with a poorer prognosis. For known high-grade appendiceal carcinoma without peritoneal or distant metastasis, a right colectomy is appropriate surgical therapy. Those found to have nodal metastases should be considered for systemic chemotherapy, with regimens used for colon carcinoma.

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