Laparoscopic treatment of perforated appendicitis

Abstract

The use of laparoscopy has been established in improving perioperative and postoperative outcomes for patients with simple appendicitis. Laparoscopic appendectomy is associated with less wound pain, less wound infection, a shorter hospital stay, and faster overall recovery when compared to the open appendectomy for uncomplicated cases. In the past two decades, the use of laparoscopy for the treatment of perforated appendicitis to take the advantages of minimally invasiveness has increased. This article reviewed the prevalence, approaches, safety disclaimers, perioperative and postoperative outcomes of the laparoscopic appendectomy in the treatment of patients with perforated appendicitis. Special issues including the conversion, interval appendectomy, laparoscopic approach for elderly or obese patient are also discussed to define the role of laparoscopic treatment for patients with perforated appendicitis.

Key Words: Perforation, Laparoscopic appendectomy, Intra-abdominal abscess, Cost

Core tip: Appendicitis is the most common abdominal emergency, and the perforated appendicitis often leads to serious infectious complication. There are concerns of using laparoscopic appendectomy to perforated appendicitis This article reviewed the recent progress and concerns in using laparoscopic appendectomy for treating perforated appendicitis.

INTRODUCTION

Laparoscopic appendectomy (LA) is a safe and effective procedure for the treatment of simple appendicitis. Laparoscopic approach is superior to open appendectomy (OA) in terms of postoperative wound infections, analgesia requirement, hospital length of stay (LOS), return to work, and overall recovery[1,2]. With the accumulated experience in simple appendicitis, LA has been attempted more frequently for treating perforated appendicitis. In our retrospective, comparative study, 91 of 99 patients with perforated appendicitis were treated successfully by LA, and the wound infection rate (15.2%) was lower than that of the OA group (30.7%)[3]. Similar favorable outcomes in terms of LOS, antibiotic usage, return of oral intake, and rate of wound infection of LA than OA for patients with perforated appendicitis were shown, too[4-6]. However, the higher incidence of intra-abdominal abscess (IAA) formation following the uses of laparoscopy for perforated appendicitis were reported[7-9], which remained a major concern in using LA for perforated appendicitis[10-12]. Compared to OA, the beneficial role of LA for perforated appendicitis is still controversial. This literature review summarized the past and the current status on the effectiveness and outcomes of LA in compared to OA for perforated appendicitis. We search the website for original articles whose keywords included laparoscopic, appendicitis, and perforation. Case reports or case series which lack in a control group for comparison were excluded from this review.

TREND AND TECHNIQUE OF LA TO TREAT PERFORATED APPENDICITIS

Use of laparoscopy for perforated appendicitis: Increased

With the advance of laparoscopic instruments and accumulated experience in using LA for uncomplicated appendicitis, LA has been more frequently used for perforated appendicitis. Nationwide studies in United States demonstrated that utilization rate of LA for perforated appendicitis increased from 45.0% in 2006 to 50.5% in 2008 for adults[6], and from 9.9% in 1999 to 46.6% in 2007 for children[13] Another nationwide population-based study in Taiwan also illustrated that the increased use of LA for both simple and perforated appendicitis from 2001 to 2008[14]. Besides, reports showed that the use of LA on females increased, although the majority of patients were males[6,15,16].

Who uses LA to treat perforated appendicitis: Surgeons’ characteristics

In the establishment of a new technique for treating an old disease, the surgeons’ training and decisions are always important. In Taiwan, LA was more popularly used to treat uncomplicated and complicated appendicitis by surgeons younger than 50 years, by surgeons who practice in urban rather than rural areas, and by surgeons in teaching rather than district hospitals[15]. The same happened in United States where surgeons recertifying after 10 years performed more laparoscopic procedures, when compared with those recertifying after 20 or 30 years[17]. The training of using laparoscopic surgery in their residency might account for these characteristics.

Is single-port better than multiport technique?

The most common approach of LA is by a multiport laparoscopic technique, whether the appendix perforated or not. Further efforts to minimize the invasiveness of the procedure led the idea of performing a single-port LA. With the recent development of multichannel, single-port articulating and curved instruments, successful single-port LA have been reported in adult[18] and pediatric patients[19,20]. Kim et al[18] had performed a successful single-port procedure for 2 perforated appendicitis in 43 adult patients. Although the rate of conversion to multi-port was high (25% need additional trocars) and technically demanding, Muensterer et al[19] still considered single-port approach is achievable for children with perforated appendicitis. However, most of the perforated appendicitis cases were not diagnosed preoperatively in these series. The feasibility of using single port LA for perforated appendicitis remains undetermined. At present, multiport approach technique is still the choice of approach for patients with perforated appendicitis.

Methods of the appendiceal stump closure

The insecure management of the appendiceal stump is one of the most important causes that lead to the formation of IAA when treating appendicitis. Different techniques including endoclips, endoloops, or staplers have been used for secure ligations of appendiceal stumps while performing LA[21]. Staplers have the advantage of relatively easy handling and a possible reduction in the incidence of leakage in advanced appendicitis owing to closure with a double row of staples[22]. Kazemier et al[23] reported that using a stapler for an appendiceal stump is safer than an endoloop: because there is an evident reduction in operation time, wound infection, and postoperative ileus. Similarly, Beldi et al[24] reached the conclusion in a study of 6489 patients that stapler usage is safer than endoloops in terms of IAA formation and readmission. On the other hand, using endoloops is advantageous in reducing medical costs because they are 6 to 12 times cheaper than stapling devices. Concerns of using an endoloop in perforated appendicitis included first, it takes good surgical technique to settle a knot and adjust the strain in laparoscopic procedure; Second, the risks of stump leakage by using endoloops may be higher, because the fragile, necrotic appendiceal tissue might not sustain the ligature. Sahm et al[25] showed that the rate of IAA after using endoloops or staplers for perforated appendicitis is not significantly different with the use of staplers in the majority of patients (3.5% vs 4.2%, P = 0.870), and staplers were indicated in only a few patients. The decision of using an endoloop or a stapler for appendiceal stump closure in perforated appendicitis needs more studies.

Efficacy of peritoneal lavage

The practice of peritoneal lavage for the management of perforated appendicitis was common, only 7% the respondents in the survey of North American pediatric surgeons in 2004 reported using no irrigation[26]. However, the efficacy of lavage remains a controversy. The pros suggest that thorough lavage under laparoscopic guide before closing the wound decrease residual fluid accumulation in patients with perforated appendicitis[3]. Ohno et al[27] has shown a large amount of lavage fluid is necessary to minimize residual contamination in perforated appendicitis. The European guideline also recommended thorough peritoneal lavage (6-8 L) and aspiration can minimize the IAA rate in complicated appendicitis[28]. In contrast, the cons proposed that lavage itself might help spreading the infectious materials. One comparative study documented a higher abscess rate when irrigation was used during appendectomy for perforated appendicitis including LA[29]. A prospective randomized study for children also showed that there is no advantage to irrigation of the peritoneal cavity over suction alone during LA for perforated appendicitis, for the rate of IAA was similar (18.3% vs 19.1%, P = 1.0) but the operation time was longer[30]. The necessity of peritoneal irrigation in LA for perforated appendicitis remains debatable.

Routine abdominal drainage

To reduce fluid collections and thus reduce postoperative intra-abdominal infectious complications, drains have been routinely used in various abdominal surgeries. There are two different intentions to drain the abdominal cavity in the setting of emergency surgery, therapeutic and prophylactic[31]. Placement of a drain tube after LA for perforated appendicitis consisted of both to evacuate the residual abscess and prevent recurrent IAA. The positioning of a drain for the aspiration of the residual fluid after peritoneal lavage in the first 24 h postoperatively might lower the incidence of IAA in case of insufficient lavage. Routine prophylactic drainage of the abdominal cavity after LA has been a common practice in order to prevent abscess formation in case of perforation with pre-existing abscess[32], but this concept has been challenged. Sleem et al[5] has found placement of a pelvic drain did not reduce the rate of IAA at the time of LA or OA. Allemann et al[33] showed that patients without drain had significantly less overall complications (7.7% vs 18.5%, P = 0.01) and a shorter hospital LOS (4.2 vs 7.3 d , P < 0.0001) in their case match study. Similarly, Pessaux et al[32] also reported increased wound infection rates after drainage of the abdominal cavity during laparoscopic interventions. It seems that routine drainage of the abdominal cavity for complicated appendicitis might not be not routine, because the intentions to reduce intra-abdominal infections were questioned[32,33].

SAFETY OF USING LA TO TREAT PERFORATED APPENDICITIS

Conversion of laparoscopy to an open procedure for perforated appendicitis

Laparoscopic treatment of perforated appendicitis is technically more demanding and has been associated with a higher conversion rate than treating uncomplicated appendicitis[34-36]. The conversion rates from LA to OA from 0% to 47% have been reported[3-4,11,36-39] and correlated with the surgeon’s experience[36]. The conversion rate did have an impact on the outcomes analysis between LA and OA for perforated appendicitis. A higher conversion rate would place more patients undergoing converting appendectomy into the LA group because the use of “intention to treat” analysis. In this case, the advantages of LA than would be underestimated[21]. Piskun et al[39] found a 19.2% conversion rate of patients undergoing LA for perforated appendicitis and concluded that conversion is associated with longer operation time and increased rates of morbidities. Vahdad et al[40] demonstrated that pediatric patients who required a conversion procedure take a longer operation time and carry higher risks of re-admissions, re-operations, and occurrence of wound infections compared to either LA or OA. These results might be simply explained by the presence of more severe inflammation in the conversion groups or an impact of a longer operation time. It deserves further studies to assess the actual role of the conversion procedure on the outcomes of patients with perforated appendicitis.

Surgical mortality

The results of population-based studies from United States regarding postoperative mortality and morbidities were listed in Table 1. As shown in Table 1, Masoomi et al[6] reported that the in-hospital mortality rate was significantly lower for LA than OA for perforated appendicitis, so as Tiwari et al[16]. The study by Tuggle et al[12] illustrated a not significantly lower mortality rate of LA compared to OA (0.54% vs 1.11%, P = 0.11) The small mortality and the small differences in percentage between the two procedures can be attributed to the fact that appendicitis is not commonly a fatal disease for adult patients.

Table 1 Summary of the population-based studies on the mortality and morbidities for patients with perforated appendicitis in United States.

Study	Patient numbers	Mortality	Overall morbidities	30-d readmission	Wound infection	IAA	Bowel obstruction
Tuggle et al[12]	LA: 2060	LA: 0.54%	-	-	LA: 2.56%b	LA: 6.74%b	-
	OA: 730	OA: 1.11%			OA: 8.05%	OA: 3.69%
		(P = 0.11)
Tiwari et al[16]	LA: 5212	LA : 0.13%b	LA: 17.43%b	LA: 5.04%	-	-	-
	OA: 5323	OA: 1.03%	OA: 26.68%	OA: 5.93% (P = 0.05)
Masoomi et al[6]	LA: 69840	LA: 0.06%b	LA: 18.75%b	-	LA: 0.58%b	LA: 1.65%b	LA: 1.24%b
	OA: 68344	OA: 0.31%	OA: 26.76%		OA: 2.09%	OA: 3.57%	OA: 2.84%
Oyetunji et al[13]	Total 72787	-	-	-	-	LA: 4.9%	-
	LA: 29.2%					OA: 3.8%
	OA: 70.8%
Jen et al[45]	LA: 9246	-	-	LA: 6.3%	LA: 5.5%	-	LA: 2.0%
	OA: 21347			OA: 6.9%	OA: 6.4%		OA: 2.6%
				(P = 0.16)	(P = 0.02)		(P = 0.02)

^bP < 0.01 vs perforated appendicitis (OA) group. LA: Laparoscopic appendectomy; IAA: Intra-abdominal abscess.

Overall morbidities

Early studies on LA often reported higher complication rates for LA than OA[41,42], but recent studies have noticeably found LA to have lower complication rates than OA[21]. The rates of overall postoperative morbidities for perforated appendicitis with LA has been shown to be consistently lower than OA, varied from 12.8% to 39.5% for LA and 26% to 37% for OA[3,11,36]. As shown in Table 1, Tiwari et al[16] showed a 9.2% reduction of the overall complication rates by LA than OA (17.43% vs 26.68%, P < 0.001). Similarly, Masoomi et al[6] also illustrated that the overall frequency of postoperative complications was significantly lower for LA than OA for perforated appendicitis.

30-d readmission rate

Since Bonanni et al[8] reported 5 of 11 patients who underwent LA for perforated appendicitis required readmission, the 30-d readmission rate after discharge remained a concern in LA for perforated appendicitis. For children, Vahdad et al[40] have shown that LA resulted in fewer readmissions (1.3% vs 12.3%, P = 0.006) compared to OA. As shown in Table 1, Tiwari et al[16] also reported a relatively less 30-d readmission rate in LA compared to OA (5.04% vs 5.93%, P = 0.050). Wang et al[15] showed that patients undergoing LA had significantly lower odds of 30-d readmission than patients undergoing OA for perforated appendicitis. Consistent with the results in reducing the postoperative complications, most recent studies concluded a lower 30-d readmission rate for perforated appendicitis in LA than OA[15,16,40].

INFECTIOUS COMPLICATIONS

Wound infection rate

Most of the studies reported that LA reduced the postoperative wound infection rate than OA in adults[2-6,11,12,36,38] and children[10,40,43-45] with perforated appendicitis. The wound infection rates in the reported series were 0% to 15% for LA, compared to 2% to 48% for OA[21]. The contamination of the perforated appendix or infected discharge of the incision wounds may explain the higher wound infection rate in treating complicated appendicitis than in simple appendicitis. In practice, the removed appendix is placed in an endoscopic bag before retrieved out of abdomen, and the accumulated fluid is aspirated before closing the wound in laparoscopic appendectomy procedure. These maneuvers prevent the abdominal wall from being in contact with the infected source, and thus reduce the rate of wound infection[4].

Intra-abdominal abscess rate

A major concern in earlier studies about using LA for perforated appendicitis was the increased occurrence of IAA. The occurrence of IAA leads to prolonged antibiotic usage, increased rate of readmission, and increased medical costs. Frazee et al[7] reported 26% IAA in 34 cases of gangrenous perforated appendicitis treated by LA. As experience in using LA for perforated appendicitis accumulated, the occurrence of postoperative IAA has improved. Some studies have shown the rates of post-operative IAA is similar[3-5,10-11,36-38,40,43] or even lower[6,46] in LA compared to OA. Masoomi et al[6] also reported a superior outcome of reducing the rate of IAA in LA than OA (1.65% vs 3.57%, P < 0.01) on a large administrative basis. However, the incidences of IAA following LA for perforated appendicitis were still high in some recent reports[12,45,47]. The risk factors associated with IAA formation after LA include the methods of the appendiceal stump closure, efficacy of peritoneal irrigation, and the role of routine abdominal drainage which have been discussed in the previous sections.

NON-INFECTIOUS COMPLICATION (SMALL BOWEL OBSTRUCTION)

Small bowel obstructions (SBO) can occur following any abdominal surgery secondary to adhesion formation. SBO following appendectomy has been thought to be uncommon with the rate to be approximately 1%[48]. Leung et al[49] reported a 2.8% rate of SBO following 1777 appendectomy in over an average 4.1-year follow-up period. The authors found that the risk factors of developing SBO included perforated appendicitis, but did not find significant difference in SBO rates following LA compared with OA. However, as shown in Table 2, Masoomi et al[6] found that application of LA for perforated appendicitis was associated with a lower rate of SBO than OA (1.24% vs 2.84%, P < 0.01). A pediatric study by Tsao et al[50] demonstrated that 7 (6 perforated) patients required adhesiolysis for SBO after OA, in contrast to 1 patient after LA (P = 0.01). The authors argued that LA may be associated with less adhesion formation for patients with perforated appendicitis, and hence a lower rate of SBO. As shown in Table 1, Jen et al[45] also demonstrated a lower rate of postoperative SBO in LA than OA.

Table 2 Population-based studies of patients with perforated appendicitis in United States: Profiles of study, length of stay, and medical costs.

Study	Patient population	Data source	Study period	Patient numbers	Length of hospital stay, d	Medical costs, USD
Tuggle et al[12]	Adults	NSQIPD	2005-2007	LA: 2060, OA: 730	LA: 3.97b	-
					OA: 5.13
Tiwari et al[16]	Adults	UHCD	2006-2008	LA: 5212	LA: 4.34b	LA: 12125b
				OA: 5323	OA: 7.31	OA: 17594
Masoomi et al[6]	Adults	NISD	2006-2008	LA: 69840	LA: 4.0b	LA: 32487b
				OA: 68344	OA: 6.0	OA: 38503
Oyetunji et al[13]	Children < 18 yr	HCUP	1998-2007	Total: 72787	LA: 5.06b	LA: 27951b
				LA: 29.2%	OA: 5.60	OA: 24965
				OA: 70.8%
Jen et al[45]	Children < 18 yr	CAPDD	1999-2006	LA: 9246	LA: 5.2b	-
				OA: 21347	OA: 5.5

^bP < 0.01 vs perforated appendicitis (OA) group. NISD: Nationwide Inpatient Sample Database; UHCD: University Health System Consortium Database; HCUP: Healthcare Cost and Utilization Project; CAPDD: California Patient Discharge Database; NSQIPD: (American College of Surgeon’s) National Surgical Quality Improvement Project Database; LA: Laparoscopic appendectomy; IAA: Intra-abdominal abscess.

EFFICIENCY AND COST IN USING LA TO TREAT PERFORATED APPENDICITIS

Impact of surgical procedures on duration of operation

Most studies for adults suggested that LA has a similar[2,36,37] or longer[3,11,39] operation time than OA, while few reported a shorter operation time[4,38]. The disparity in the results of these reports may be attributed to the surgeons’ experience in LA and the effect of a learning curve[21].

Although the majority of reports illustrated a longer operation time for LA[44,51,52], some studies concluded that there is no difference in operation time between LA and OA for children with complicated appendicitis[40,53]. Increased experience of the pediatric surgeons in LA for perforated appendicitis could explain the lack of a significant difference in operation time[53]. The issue of operation time between LA and OA for perforated appendicitis is in debate, both for the adult and pediatric patients.

DOES A PATIENT UNDERGOING LAPAROSCOPIC TREATMENT OF PERFORATED APPENDICITIS HAVE A FASTER RECOVERY?

Postoperative analgesia

Some studies showed the value of LA in reducing the postoperative analgesics use, and concluded that LA cause less pain than OA for adult patients with perforated appendicitis[3,4,11]. In contrast, most of the reports for children operated on by LA showed no difference[54,55]. It is difficult to form a conclusion because lack in a pain scoring system in most of these reports.

Restart of oral intake

While some studies have shown that there was no significant difference in the time of restart of oral intake between LA and OA for children with perforated appendicitis[10,55], Lin et al[3] illustrated that return of oral intake was 1.8 d earlier in LA than OA in adult patients. Fukami et al[4] and the other series[11,36] also demonstrated the same trend. However, lack in a precise definition of restart of oral intake (liquid or solid food) in these studies precluded a further analysis.

Length of hospital stay

Similar to the results of uncomplicated appendicitis treatment[56], LA was reported to reduce the hospital LOS either in adults[3-4,11,38,57] or in children[10,58,59] with perforated appendicitis. Because most of these case series were performed by surgeons experience in laparoscopy, it is prudent to assess LOS by analyzing studies on a large administrative basis. Yeh et al[14] concluded LA was associated with comparable costs and reduced LOS for patients with complicated appendicitis when compared with OA. Another population-based study in Taiwan also showed that patients undergoing LA for perforated appendicitis had significantly lower odds of 30-d readmission and a shorter LOS than patients undergoing OA[15]. As shown in Table 2, several nationwide population-based studies from United States including adult[6,12,16] and pediatric[13] patients assessed the impact of laparoscopic treatment on LOS for perforated appendicitis. Masoomi et al[6] has analyzed a total of 573244 adults undergoing urgency appendectomy from the Nationwide Inpatient Sample Data. They concluded that the difference in LOS was much more pronounced than non-perforated (0.7 d) where LA was shorter than OA by 2 d (4.0 d vs 6.0 d, P < 0.01) for perforated appendicitis. All these studies concluded that LA was associated with a shorter hospital LOS compared to OA for perforated appendicitis[6,12,13,16].

Medical cost

When examining the medical costs, some early studies found that the total hospital charges of LA were higher than OA[60,61]. Factors contributing to the higher operative costs of LA consisted of disposable laparoscopic instruments, high energy devices, and equipments for securing the appendiceal stumps. Both the in hospital costs and outpatient costs have to be considered in economical evaluation. In Germany, the health technology assessment reports concluded that the total in-patient costs of both procedures are approximately the same. They found that LA is associated with additional operation costs of approximately 150 to 200 Euro in comparison with OA, and there are cost savings of approximately 200 Euro due to shortening the hospital LOS. The total costs of both procedures lie in the same range because similar direct and indirect costs (costs of the productivity loss). The incremental cost-effectiveness ratio of LA and OA was thus driven to zero[62].

In other countries, studies for adults[14] and children[13] have demonstrated that LA was associated with comparable costs and reduced LOS for complicated appendicitis. Moreover, as shown in Table 2, Tiwari et al[16] and Masoomi et al[6] concluded that reduced medical costs for perforated appendicitis in LA than OA in their population-based studies. Despite the actual impact of LA on the medical costs vary in different regions, there is a definite economic benefit from a patient-centered social perspective with a shorter hospitalization and quicker return to daily activities[63].

SPECIAL CONSIDERATIONS

Laparoscopic interval appendectomy for perforated appendicitis with phlegmon

Appendiceal abscess or phlegmon is found in about 3.8% of patients with appendicitis[64]. The management of patients with perforated appendicitis with a sizeable inflammatory phlegmon is usually conservative. Immediate appendecotmy is technically demanding with distorted anatomy, adhesive loops of bowel, and difficult to close the appendiceal stump because of the inflamed tissues[65]. Not infrequently, early laparoscopic treatment will become open conversion, ileocecal resection, or right hemicolectomy due to technical problems or distorted anatomy[66]. An alternative treatment for these patients is nonsurgical, including intravenous antibiotics and selective percutaneous drainage. Interval appendectomy has been advocated to prevent the recurrence of appendicitis and reported feasible (mostly LA) by some surgeons[67,68]. The advantage of the interval appendectomy is to perform the operation at a time when peritoneal contamination has resolved, potentially resulting in fewer intraoperative and/or postoperative complications[64]. However, the superiority of early LA over interval LA has been shown in some recent reports[69,70]. One pilot randomized trial found no major differences in outcomes when comparing early LA with interval LA in patients with well-formed IAA[69]. In a randomized study for children with appendiceal phlegmon, Blakely et al[70] concluded that early LA significantly reduced the time away from normal activities and the rates of overall adverse events than interval LA, with a comparable conversion rate to OA. Lastly, a study by Schurman et al[71] illustrated that families managed with interval LA are likely to suffer more negative impact on the quality of life than those managed with immediate LA. Based on these results, the issue of whether interval LA is superior to early LA for an appendiceal phlegmon remains a topic of debate.

GERIATRIC PATIENTS

As the size of the elderly population has been increasing, an increase in the occurrence of appendicitis in the elderly can be expected. A higher perforation rate in the geriatric population than younger age groups presented a challenge to surgeons[72]. The rate of perforation appendicitis has been reported as high as 50% in the elderly patients with appendicitis[73] . The high perforation rate in the elderly may attribute to the delay in diagnosing appendicitis, atypical presentations and underlying comorbidities in elderly patients[73]. Paranjape et al[74] has reported that the classical presentation of appendicitis was seen in only 10% of the elderly patients. Diagnostic discrepancies greatly influence the perforation rate of appendicitis in the geriatric population. In a retrospective analysis of 113 elderly patients, Storm-Dickerson et al[72] showed a decreased perforation rate over 10 years from 72% to 51% by utilizing computed tomography (CT) scanning on seriously ill patients for early diagnosis. Besides, Italian consensus guidelines on LA also recommended the routine use of preoperative CT for elderly patients to exclude other pathology[75].

The utility rate of LA for perforated appendicitis in elderly patients (age ≥ 65 years) has been increasing, but still lower than those in younger age groups[73,76]. The use of pneumoperitoneum which might compromise the cardiopulmonary co-morbidities of the elderly, and the longer operation time might be the main concerns that surgeons favored open rather than laparoscopic appendectomy in this patient population. There were a few studies reporting the outcomes of LA to OA in the elderly population[2,14,74,76]. Paranjape et al[74] recommended using preoperative CT to increase the diagnosis rate, and they successfully performed LA for 18 of 29 elderly patients with perforated appendicitis. They concluded that laparoscopic cases had a shorter LOS and fewer complications than open cases with comparable operation time[2,14,74,76]. In 2006, Harrell et al[76] reported that the elderly patients treated by LA for their perforated appendicitis had a shorter LOS, a higher rate of discharge to home and equivalent cost when compared with OA. In another population- based study, Masoomi et al[73] reported the increased use of LA, the lower overall mortality and complication rates, shorter LOS, and less hospital costs than OA for treating perforated appendicitis in the selected patients elder than 65 year-old. Table 3 summarizes the results of 2 large studies comparing the outcomes between LA and OA for the management of elderly patients with perforated appendicitis. The utility of LA in elderly patients with perforated appendicitis deserves further studies.

Table 3 Summary of 2 population-bases studies for elderly patients with perforated appendicitis.

Study	Harrell et al[76]	Masoomi et al[6]
Study period	1997-2003	2006-2008
Data source	NCHAPD	NISD
Patient numbers	LA: 203, OA: 1289	LA: 13765, OA: 18915
Length of hospital stay, d	LA: 6.8, OA: 9.0b	LA: 5.8, OA: 8.7b
Routine discharge	LA: 86.6%, OA: 70.9%b	-
Mortality	LA: 1.0%, OA: 2.98%	LA: 1.4%, OA: 2.63%b
	(P = 0.10)
Overall complication rate	LA: 23.65%, OA: 23.74%	LA: 36.27%, OA: 46.92%b
	(P = 0.97)
Surgical charge, USD	LA: 22334, OA: 23855	LA: 47339, OA: 57963b
	(P = 0.93)

^bP < 0.01 vs perforated appendicitis (OA) group. NISD: Nationwide Inpatient Sample Database; NCHAPD: North Carolina Hospital Association Patient Data; LA: Laparoscopic appendectomy.

OBESE PATIENTS

Obesity is now an epidemic problem worldwide. Surgeons were once reluctant to perform laparoscopic procedures on obese patients for difficulties including the access of abdominal entry, inflation-related ventilation problem, poor visualization for the intra- abdominal fat, longer operation time[77] and also the higher pre-operative sepsis rate[78].

With the advancement of laparoscopic skills, surgeon gradually favored using LA rather than OA on obese patients with appendicitis. Corneille et al[79] reported their successful LA in 73 of 85 patients with BMI more than 30, though 4 of the 12 converted LA had perforated appendicitis[79,80]. Varela et al[80] reported the cumulated experience of LA in 906 morbid obesity patients with appendicitis, and found that LA was associated with less overall complication, shorter hospital stay and equivalent or lower hospital charges when compared to OA. However, limited data was available for the use of LA in obese patients with perforated appendicitis. Table 4 showed the results of 2 population-based studies of using LA for obese patients with perforated appendicitis. Compared to OA, the overall complication rate and costs were lower in the LA group[80]. Another subgroup analysis using the database of American College of Surgeons National Surgical Quality Improvement Program also showed that the overall morbidity was lower in obese patients receiving LA[78]. Although the superiority of LA seems obvious in these studies, the selection bias existed. A randomized trial would be more informative to define the role of LA on obese patients with perforated appendicitis.

Table 4 Summary of 2 population-bases studies for obese patients with perforated appendicitis.

Study	Varela et al[80]	Masoomi et al[6]
Study period	2002-2007	2006-2008
Data source	UHCD	NISD
Patient numbers	LA: 238, OA: 441	LA: 6769, OA: 7110
Definition of obesity	BMI ≥ 40 kg/m2	BMI ≥ 30 kg/m2
Length of hospital stay, d	LA: 5, OA: 7b	LA: 4.4, OA: 6.5b
Mortality	LA: 0%, OA: 0%	LA: 0%, OA: 0.50%b
Overall complication rate	LA: 18%, OA: 27%b	LA: 22.34%, OA: 34.65%b
Mean costs, USD	LA: 12300, OA: 16600b	LA: 36483, OA: 43901b

^bP < 0.01 vs perforated appendicitis (OA) group. NISD: Nationwide Inpatient Sample Database; UHCD: University Health System Consortium Database; LA: Laparoscopic appendectomy; BMI: Body mass index.

CONCLUSION

With the accumulated experience in simple appendicitis, LA has been more frequently used for perforated appendicitis in adults and children by surgeons experienced in laparoscopy. Although the operation time of LA may be longer, most studies have concluded that LA is superior to OA in terms of a faster recovery and less morbidities. LA is associated with a shorter hospital LOS, a lower mortality rate, a lower overall complication rates, a lower 30-d readmission rate, a lower SBO rate, a lower wound infection rate, and comparable costs in compared to OA for patients with perforated appendicitis. IAA remains a major concern in LA for perforated appendicitis, and the roles of irrigation and routine drainage to reduce risks of IAA remain debatable. Conversion procedure from LA to OA may be associated with higher rates of morbidities. For perforated appendicitis with phlegmon, the interval LA does not provide definite advantages over early LA. Laparoscopic treatment may be beneficial for some subsets of population, such as elderly and obese patients. It deserves more randomized and population-based studies to definite the actual roles of LA in the management of perforated appendicitis.