Right sided diverticulitis in western countries: A review.

BACKGROUND: Although the treatment guidelines for left sided diverticulitis are clear, the management of right colonic diverticulitis is not well established. This disease can no longer be ignored due to significant spread throughout Asia. AIM: To analyse epidemiology, diagnosis and treatment of right-sided diverticulitis in western countries.
METHODS: MEDLINE and PubMed searches were performed using the key words "right-sided diverticulitis'', ''right colon diverticulitis'', ''caecal diverticulitis'', ''ascending colon diverticulitis'' and ''caecum diverticula'' in order to find relevant articles published until 2021.
RESULTS: A total of 18 studies with 422 patients were found. Correct diagnosis was made only in 32.2%, mostly intraoperatively or via CT scan. The main reason for misdiagnosis was a suspected acute appendicitis (56.8%). The treatment was a non-operative management (NOM) in 184 patients (43.6%) and surgical in 238 patients (56.4%), seven of which after NOM failure. Recurrence rate was low (5.45%), similar to eastern studies and inferior to left -sided diverticulitis. Recurrent patients were successfully conservatively retreated in most cases.
CONCLUSION: The management of right- sided diverticulitis is not well clarified in the western world and no selective guidelines have been considered even if principles are similar to those with left- sided diverticulitis. Wrong diagnosis is one of the most important problems and CT scan seems to be the best imaging modality. NOM offers a safe and effective treatment; surgery should be considered only in cases of complicated diverticulitis or if malignancy cannot be excluded. Further studies are needed to clarify the correct treatment. ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.

Core Tip: This paper underlined the importance to collect more data on right-sided diverticulitis to understand if it is a more common condition than we thought, and if we really need more selective guidelines or we can simply apply the principles already proposed for left-sided diverticulitis.

INTRODUCTION

Historically, diverticula in western countries are mostly located in sigmoid colon while right-sided diverticulosis (RSD) is rare. Conversely, colonic diverticula are mostly located on the right colon in eastern patients in contrast to those in Europe and the United States[1,2]. Recently several studies show an important spread of RSD in the world over Asia[3-5].

Regarding the diverticula of the right colon, we differentiate the diverticula of the cecum (solitary or multiple) and the ascending colon. In 1912, Potier[6] first described a case of cecum diverticulum. While the first case of diverticulitis in the ascending colon was described by Telling et al[7] in 1916, in this review we analyzed both subtypes.

The etiology and the real prevalence of this difference is still unclear. All studies about management of acute right-sided colonic diverticulitis (ARCD) are related to the Asian population and no specific guidelines are still available. The aim of the present study was to review epidemiology, diagnosis and treatment of ARCD to better analyze this disease in Western populations.

MATERIALS AND METHODS

Literature search

An extensive search for literature was carried out using MEDLINE (PubMed) and Cochrane Database of Collected Reviews for potentially relevant studies between January 1, 1990, and January 1, 2021.

The terms used for the search were: ‘‘right-sided diverticulitis’’, ‘‘right colon diverticulitis’’, ‘‘caecal diverticulitis’’, ‘‘ascending colon diverticulitis’’ and ‘‘caecum diverticula’’.

Exclusion criteria were studies based on the Asian population, left-sided diverticulitis, undefined laterality or both left-sided and right-sided diverticulitis, irrelevant publications, age < 18 years. Articles not written in English or full text not available as well as case reports and case series (< 5 patients), review articles and letters to the editor were excluded.

Right-sided laterality was defined as diverticulitis involving the cecum or the ascending colon until hepatic flexure.

“Correct diagnosis” was defined as radiologically confirmed diagnosis of diverticulitis, before any medical or surgical treatment.

“Presumptive diagnosis” was defined as diagnosis of diverticulitis deemed likely despite the absence of radiological confirmation, before any medical or surgical treatment.

“Diagnostic accuracy” was defined as the rate of correct diagnosis over the total number of patients analyzed.

“Non-operative management” was defined as any treatment not requiring surgery (e.g., bowel rest, antibiotics with or without percutaneous drainage).

Two reviewers (Epifani AG, Accardo C) will independently have screened titles and abstracts, evaluating the full text of potentially eligible studies. Any doubt or disagreements has been resolved by a third reviewer (Cassini D).

We included studies from Turkey because geopolitically it is also a European country and from Israel because most people are Caucasian with similar lifestyles to western countries and finally from Qatar because of their westernized diet and lifestyle.

We excluded the review by Schlussel et al[8] because their study included patients from the NIS database which is based on the international statistical classification of diseases and related health problems (ICD) coding method. By selecting the cases in this way it has not been possible to argue many of their results and we have not been able to do an adequate data extraction. Furthermore, lacking a specific code for coding ARCD, the low accuracy of this research method was also highlighted in another study in which the authors who had initially screened ARCD with ICD codes, found a high percentage of misdiagnosed cases (74%) when they subsequently analyzed every medical chart[9].

Statistical analysis

We analyzed data regarding study design, number of patients, demographic characteristics (age, sex), location of diverticula, diagnostic evaluation methods, misdiagnosis and modified Hinchey classification[10]. We also analysed data regarding the treatment distinguished between non-operative management (NOM) (every treatment not requiring surgery, e.g., bowel rest, antibiotic, percutaneous drainage) and surgery (reporting every procedure and relative approach). We therefore analysed short-term and long-term outcomes: length of stay, complications, reintervention, need for ostomy, death, recurrence (rate and type of treatment) and median follow-up. Data were analyzed with descriptive statistics.

Primary outcome was the analysis of short-term and long-term outcomes, especially regarding recurrence rate. The secondary outcome was the evaluation of diagnosis methods and percentage of misdiagnosis.

Quality of studies were evaluated by a methodological index for non-randomized studies (MINORS) score[11]. MINORS is a valid tool to easily assess the quality of non-randomized surgical studies both comparative or not (with a maximum score of 24 and 16, respectively). Of the 18 included studies, 16 had a retrospective cohort design and 2 had a retrospective cross-sectional design.

RESULTS

With our research we initially found 1375 articles. After removing 55 duplicates, we screened titles and abstracts excluding 1188 other articles. We therefore evaluated 130 full-text reviews and obtained 18 eligible studies. The entire process of screening is shown in Figure 1[9,12-28].

Figure 1

Process of studies screening.

We analysed 18 studies, for a total of 422 patients. A summary of results is shown in Table 1, Table 2, Table 3, and Table 4[9,12-28] and in Figure 2. There were 212 females (50.2%) and 190 males (45%), however in 20 patients (4.7%) sex was not recorded. Mean patient age was 50.9 years (range: 30-65).

Table 1

Study characteristics

Ref.	Year	Country	Numbers of patients	Minors	Follow-up (Mo)	Age	Male	Unc1 or Hinchey I/II	Hinchey III/IV	LOS2 (d)	Total recurrence (rate)
Lane et al[12]	1999	United States	49	7		32	30			12.7	4 (8.16%)
Violi et al[13]	2000	Italy	20	5							0
Junge et al[14]	2003	Germany	7	7	42	56	1
Papaziogas et al[15]	2005	Greece	8	10	174	54.2	6			22	1
Hildebrand et al[16]	2007	Germany	16	16		60.9	4			11
Radhi et al[17]	2011	Canada	15	7		65	6
Issa et al[18]	2012	Israel	15	12	32	52	10	15			1 (6%)
Kalcan et al[19]	2015	Turkey	6	8	6	34	4			4.5
Hot et al[20]	2015	Turkey	10	11	60	38.9	5			5
Cristaudo et al[21]	2015	Australia	13	11	12	44	8			4	0
Koshy et al[22]	2016	Qatar	10	11	18	30.4	9				0
Monari et al[23]	2017	Italy	18	11	29	50	10				0
Yardimci et al[24]	2017	Turkey	12	12	5.5	45	6	12			0
Al-Temimi et al[9]	2018	United States	33	17		56	13	20	9	7.6
Courtot et al[25]	2019	France	93	12	33	54	58	30	4		7
Destek et al[26]	2019	Turkey	22	11	24	50.9	13	22			4
Kaya et al[27]	2020	Turkey	11	12	52		7			4.6	1
Zuckerman et al[28]	2020	United States	64	13	74.4	51.2	27	60	4	5	5
Tot	29 yr	10	422		32	50.9	190 (45.2%)	179	20	5	23 (5.45%)

Uncomplicated.

Length of stay.

MINORS: Methodological index for non-randomized studies.

Table 2

Diagnosis

Ref.	Year	Country	Numbers of patients	Diagnosis pre-op1	Ultrasound	CT	Barium enema	Other	Diagn intra-op2	Misdiagnosis (appendicitis)	Cecum (solitary)	Right	PAN-Div3
Lane et al[12]	1999	United States	49	3		2	1		41	46 (nr)	49 (37)	0
Violi et al[13]	2000	Italy	20	5	3	3	3			11
Junge et al[14]	2003	Germany	7	2		2			7	5 (4)	7 (6)
Papaziogas et al[15]	2005	Greece	8	0						7 (7)	8 (nr)		2
Hildebrand et al[16]	2007	Germany	16	7						9 (5)
Radhi et al[17]	2011	Canada	15
Issa et al[18]	2012	Israel	15	15		15					3	9	3
Kalcan et al[19]	2015	Turkey	6	0					4	6	6
Hot et al[20]	2015	Turkey	10	1					10	9 (9)	10 (10)
Cristaudo et al[21]	2015	Australia	13	10	1	9			3	3 (3)	13
Koshy et al[22]	2016	Qatar	10	1		1			9	9 (9)
Monari et al[23]	2017	Italy	18	9	1	6	1	1 XR 1 colon	9	9	11	7
Yardimci et al[24]	2017	Turkey	12	12	10	2
Al-Temimi et al[9]	2018	United States	33	13						20 (11)
Courtot et al[25]	2019	France	93							6 (6)			49
Destek et al[26]	2019	Turkey	22							2 (2)	9	13
Kaya et al[27]	2020	Turkey	11	8	2	6				5 (5)	6
Zuckerman et al[28]	2020	United States	64	50		50			11	15 (10)	33	22
Tot	29 yr	10	422	136 32.2%	17 12.5%	96 70.6%	4 2.9%	2 1.9%	98 (23.2%)	162 (92) 38.39%	155 (97) 36.7%	51 12%	54 12.8%

Pre-operatively diagnosis.

Intra-operatively diagnosis.

Pan-diverticulosis (diverticulosis in all colonic segments).

CT: Computed tomography.

Table 3

Treatment and outcome

Ref.	Year	Country	Numbers of patients	NOM	Surgery	Surgery after NOM	Complications	Re-intervention	Death	Recurr1 after NOM	Recurr1 after Surg2	Recurr1 treatment
Lane et al[12]	1999	United States	49	0	49		7	4	0		4	4 Surg2
Violi et al[13]	2000	Italy	20	0	20						0
Junge et al[14]	2003	Germany	7	0	7
Papaziogas et al[15]	2005	Greece	8	0	8						1	1 NOM
Hildebrand et al[16]	2007	Germany	16		16		0
Radhi et al [17]	2011	Canada	15		15
Issa et al[18]	2012	Israel	15	15						1		1 NOM
Kalcan et al[19]	2015	Turkey	6		6
Hot et al[20]	2015	Turkey	10		10		0	0	0		0
Cristaudo et al[21]	2015	Australia	13	10	3					0	0
Koshy et al[22]	2016	Qatar	10	1	9		2			0
Monari et al[23]	2017	Italy	18		18		3	0	0		0
Yardimci et al[24]	2017	Turkey	12	12					0	0
Al-Temimi et al[9]	2018	United States	33	4	33		10
Courtot et al[25]	2019	France	93	68	25	6	19	1	0	6	1	5 NOM; 2 Surg
Destek et al[26]	2019	Turkey	22	19	3	0	0	0	0	4	0	4 NOM
Kaya et al[27]	2020	Turkey	11	6	5		2			1		1 NOM
Zuckerman et al[28]	2020	United States	64	49	15	1	2			5	0	4 NOM; 1 Surg
Tot	29 yr	10	422	184 (43.6%)	238 (56.4%)	7 (2.9%)	45 (10.6%)	6 (2.5%)	0	17 (6%)	6 (2.5%)	16 NOM; 7 Surg

Recurrence.

Surgery.

NOM: Non operative management.

Table 4

Surgical procedures

Ref.	Year	Country	Numbers of patients	DIV	AP	DIV + AP	ICR	Right colectomy	Ostomy	Open	VLS	Converted (rate)
Lane et al[12]	1999	United States	49	7	3			39	1	49
Violi et al[13]	2000	Italy	20	6				14
Junge et al[14]	2003	Germany	7				6	1	0
Papaziogas et al[15]	2005	Greece	8	6		0	2		0	8
Hildebrand et al[16]	2007	Germany	16				3	16	0	15
Radhi et a [17]	2011	Canada	15					15			15	1 (6%)
Issa et al[18]	2012	Israel	15
Kalcan et al[19]	2015	Turkey	6			5		1		4	2	2 (100%)
Hot et al[20]	2015	Turkey	10	1		9			0	10
Cristaudo et al[21]	2015	Australia	13		2			1			3	1 (33.3%)
Koshy et al[22]	2016	Qatar	10		5		4				9	4 (44.4%)
Monari et al[23]	2017	Italy	18	5			4	9	0	4	14	5 (35.7%)
Yardimci et al[24]	2017	Turkey	12
Al-Temimi et al[9]	2018	United States	33	4				29	2	23	10	2 (20%)
Courtot et al[25]	2019	France	93	1	2		6	16	2	9	16	5 (31%)
Destek et al[26]	2019	Turkey	22		2			1	0
Kaya et al[27]	2020	Turkey	11		2	2		1
Zuckerman et al[28]	2020	United States	64				6	8
Tot	29 yr	10	422	30 12.6%	16 6.7%	17 7.1%	31 13%	151 63.4%	5 2.1%	122 63.5%	70 36.5%	20 28.6%

DIV: Diverticulectomy; AP: Appendectomy; ICR: Ileocecal resection; VLS: Videolaparoscopy.

Figure 2

World map of included studies: number of patients in each country.

The diagnosis was correctly achieved or presumed in 136 cases (32.2%), via CT scan in 96 cases (70.6%), by sonography in 17 cases (12.5%), and rarely by barium enema (4 cases, 2.9%), radiography or colonoscopy (one case each, accounting for 0.2%).

A correct diagnosis was achieved only intraoperatively in 98 cases (23%), while a misdiagnosis occurred in 162 cases (38.4%), 92 of which were suspected acute appendicitis.

Diverticula were caecal in 142 cases (33.6%), located in the right colon in 41 cases (12%), mixed in 3 cases and also 54 patients (12.8%) had left-sided diverticulosis (LSD). The exact location of right-sided diverticula (whether cecal or ascending) was not reported in 242 cases (57.3%). When reported, Hinchey classification was the most used scale (42%). They have reported 159 Hinchey I/II or uncomplicated diverticulitis, 17 Hinchey III and 3 Hinchey IV cases. Misdiagnosis occurred in 131 out of 219 patients (59.8%).

The treatment was NOM in 184 patients (median 43.6%) and surgery in 238 patients (56.4%), seven of which after NOM failure (2.94%). Surgical approach was open in 122 cases (51.2%) and laparoscopic in 70 patients (with a conversion rate of 28.6%).

Regarding surgical procedures: diverticulectomy in 30 patients; primary resection and anastomoses (PRA) in 182 patients (76.4%): when specified we found 31 ileocecal resections and 151 right hemicolectomies. In 33 cases an appendectomy was performed and 17 cases were associated with diverticulectomy.

Regarding post-operative complications, 45 adverse events were recorded (even if the surgical ones are not always differentiated) (10.7%), five diverting stoma were created (1.18%) and six reoperations were needed (2.5% of surgically treated patients). No deaths were reported. The mean length of hospital stay was 5 d (range: 4–22 d), and the median follow-up was 32.5 mo (range: 5–174 mo).

Recurrence occurred in 23 cases (5.45%), sixteen of which after NOM (3.8% of total, 5.98% of NOM cases), six after surgery (1.4% total, 2.5% of surgery cases) and in one case was not reported if recurrence occurred after NOM or surgery failure (treated with antibiotic). In the other cases, treatment after NOM was NOM again in 13 cases, while three patients underwent surgery; as well as two patients after surgery were treated via NOM and four patients underwent surgery again.

DISCUSSION

Background

Diverticula presents as herniations of the bowel wall, mostly located in areas of structural weakness, such as the site of vessel penetrance. The bowel in diverticular disease patients appears shortened and shows thickened circular and longitudinal muscle layers due to elastosis. Patients with diverticular disease showed also irregular muscle bundle orientation, reduced myosin (MYH11) heavy chain gene expression, enhanced collagen crosslinking, which all contribute to the risk for bowel wall herniation[29-31].

Other relevant factors involved in the development of diverticular are abnormal bowel motility (due to altered enteric nervous system), gut microbiome, low fiber intake and western lifestyle[5-8].

Historically, RSD have been considered congenital and true (made of all layers) as opposed to LSD considered to be mostly acquired and false (made of mucosa and muscularis mucosa)[1,32,33]. Instead, according to further studies was found that most[34,35] or even all[36,37] of the cases of RSD were actually false, both solitary and multiple. This demonstrates that the underlying pathophysiology has not yet been fully clarified and that the etiology of diverticular disease on the right-side and left-side is probably more similar than we think.

The incidence of diverticular disease has been increasing in both Europe and the United States[3]. Although acute right-sided colonic diverticulitis (ARCD) is still considered a rare disease in the western world, the real incidence is not that rare[38] ranging from 5% to 20%[3,5,28,39].

Historically, a century ago it was seen in early studies that the prevalence of RSD was higher than expected (2%-5%)[40,41]. As early as 1961, Miangolarra[42] firstly describes the diverticulitis of the right colon as “an important surgical problem”.

Nevertheless, the evidence of ARCD is almost exclusively based on single-center or case reports. In fact, we found only 5 studies reporting more than 20 patients, demonstrating that it is not a widespread reality and that it is often managed according to individual surgeons[9,12,25,26,28].

In patients affected by ARCD we found that the median age was 50.9 years and was higher in patients with the Hinchey stage II than Hinchey I (45.7 vs 63, 57 years)[26]. Also, in comparison studies, we found an earlier onset than LSD (53 vs 64 years)[16,23,28].

Diagnosis

Patients affected by ARCD typically presented at the emergency department with fever, pain in the right iliac fossa and often signs of peritoneal irritation. Blood tests show leukocytosis and increased C-reactive protein[12-15,18,19,24-27]. Similar symptoms and young age are confounding factors and they can be wrongly identified with the diagnosis of acute appendicitis in most of the cases described[14,15,17,22].

Recently Zuckerman et al[28] reported that 67% of patients underwent an operation for a misdiagnosis of appendicitis. This illustrates the importance of accurate diagnostic criteria to avoid unnecessary appendectomy or even a right hemicolectomy.

In fact, the diagnostic accuracy we calculate in all the studies is a poor 32.2%, when the reported misdiagnosis rate is 38.39% (162 cases), where 56.79% of the time (92 cases) diagnosis is clearly mistaken for acute appendicitis.

Effective diagnosis is therefore the main achilles heel of ARCD. In some studies, nuanced differences emerge in the clinical presentation that could help us in the differential diagnosis such as the longer duration of symptoms[26], the presence of diarrhea in the weeks preceding the pain[21] and the absence of nausea and vomiting[20,23]. Making the correct diagnosis can be very difficult relying only on the clinical evaluation especially if we consider that the Alvarado score shows a poor negative predicting value in distinguishing acute appendicitis from ARCD[23].

The awareness of this condition and the use of the correct imaging can help us to increase the rate of correct diagnosis. So, in the Kalcan study there was a 100% misdiagnosis rate because no physician did radiological investigations[19].

According to Wilson et al[43], it is possible to make an ultrasound diagnosis of diverticulitis when there are two of the following features: thickening of the wall (≥ 4 mm), diverticula with signs of inflammation, inflammatory modifications in the pericolic fat, pericolic or intramural inflammatory mass and intramural fistulas.

We know that in expert hands sonography may allow a correct diagnosis of ARCD, directly or suspected by indirect sign[15]. We also know that has a limited utility in obese patients and is user dependent[24,32,44]; and especially in emergency cases, diagnosis of ARCD can be even more difficult without more advanced and objective imaging exams such as CT scan[19]. Therefore, the ultrasound should not be the only imaging technique in a case of suspected diverticulitis and magnetic resonance imaging (MRI) might be useful when CT is contraindicated[45,46]. Nevertheless, MRI is not always available in the emergency setting and rarely used[47]. In particular, in patients presenting with right lower abdominal pain, thin-section helical CT scan may identify or exclude other clinical conditions[48].

For both sonography and CT there are very specific diagnostic criteria for ARCD such as colonic wall thickening and edema, pericolic fat infiltration or abscess and extraluminal air around the colon[24].

In our review only 12.5% of cases were diagnosed via sonography compared to 70.6% of correct CT-driven diagnosis; while other methods of diagnosis have rarely been effective.

The importance of tomography is clear in the article by Cristaudo et al[21] in which CT scan was necessary to detect the pathology in 90% of cases. Also, in the study of Kaya et al[27] in which CT scan recognized aggressive liver cancer domains (ALCDs) where the sonography failed. Moreover, the CT scan shows the exact extent of the degree of inflammation in order to be able to accurately plan any surgical intervention[16].

Certainly, the diffusion and accessibility of this imaging technique improved the diagnostic accuracy, as can be seen from the increase in the diagnosis rate in two periods, before and after 2007, in Zuckerman's study[28].

Finally, when surgical exploration may be the only way to obtain an effective diagnosis and allow the most adequate treatment then the minimally invasive approach may be the most suitable way to do it[23].

Treatment

For the first time, in the latest WSES 2020 update for the management of acute colonic diverticulitis in the emergency setting, ARCD is defined as a distinct clinical entity and the principles of diagnosis and treatment are suggested to be similar to those in ALCD. However, patients with RCD require surgery less often than patients with ALCD, but their management is not well defined, and no unique guidelines have been proposed until now[49].

The correct diagnosis is very important because it allows a conservative management to successfully treat uncomplicated ARCD (uARCD)[21,24,25].

But historically the treatment of ARCD has been mostly surgical and it has always remained at the discretion of the surgeon since the first reported surgical treatment of acute right-side diverticulitis was made by an American surgeon in 1954[50].

As for surgical treatment, there are multiple options for complicated forms such as conservative (appendectomy), limited (diverticulectomy), or extensive (ileocecal resection or right hemicolectomy[12,32,51].

Mostly the indication for surgery was secondary to a wrong diagnosis, leading to the aggressive choice of surgical procedures based on the intraoperative findings[16,23,25]. Lane et al[12] for example advocated diverticulectomy in cases of a solitary diverticulum, and immediate right hemicolectomy in the case of cecal phlegmon or multiple diverticula.

Over the years, the interventions have been less and more reasoned. If the inflamed area was limited, then a narrow diverticulum resection has been proposed as a safe and effective technique[20,23]. And this attitude was confirmed after a 14-year follow-up study, with a unique case of recurrence 8 years after the reported episode[15].

Furthermore, removing the appendix was also useful for two reasons. First, there was a “contiguous appendicitis” secondary to diverticular inflammation[15,25] and second because the removal of the appendix would have allowed a simpler diagnosis in case of a new episode of pain in the right iliac fossa[19,22,27].

As much as 40% of ARCD patients underwent right hemicolectomy after finding a mass mimicking colon cancer[32]. It is also true that in some cases the histological analysis on the surgical specimen found the presence of adenocarcinoma of the cecum associated with multiple diverticula[17]. According to Radhi et al[17], single diverticula are more present in young patients and tend to be symptomatic, while multiple diverticula are incidental findings or associated with carcinoma in older patients.

Intraoperative findings of suspected tumors or complicated patients with significant extent of diverticulitis remained therefore the only reasons for extensive surgery[15,16,19,20] and could potentially avoid a formation of diverting stoma[9].

Analyzing our research, we found a very low number of stoma (1.18%) and reoperations needed (2.5%). Furthermore, our results agree with the recent studies which shows that need for ostomy was significantly less frequent in the ARCD group than ALCD (6.3% vs 62.5%) probably also due to the more favorable anatomical location of right colon (being retroperitoneal may limit the spread of inflammation in contrast to sigmoid colon) with ileocolic anastomosis burdened by a lower risk of leak compared to the colorectal ones[52].

Although the use of laparoscopy was often secondary to a wrong diagnosis of acute appendicitis[9], since the first laparoscopic diverticulectomy was performed in 1994[53], a more careful selection of patients allowed in experienced hands to perform even colonic resection with primary anastomosis with minimally invasive approach[16,23].

Conversion was mainly due to the detection of small bowel dilatation or difficult clinical picture such as free fluid or big abscess when laparoscopic approach was initially chosen to perform appendectomy instead[23].

Finally, Hildebrand et al[16] stated that there was no big difference in the treatment of right-sided diverticulitis compared to left-sided diverticulitis. We confirm his conclusion, and we report in Figure 3 a synthesis of the therapeutic options highlighted in the therapeutic diagnostic algorithm inspired by the study of Kaya et al[27].

Figure 3

Diagnostic-therapeutic algorithm. uARCD: Uncomplicated acute right-sided colonic diverticulitis; NOM: Non-operative management; cARCD: Complicated acute right-sided colonic diverticulitis; VLS: Videolaparoscopy.

Outcomes

In our review we found a low recurrence rate (5.45%). Cristaudo et al[21] and Yardımcı et al[24] had no recurrence at all after NOM management, demonstrating the benign course of the disease. Other studies had a low range of recurrence (6%-21%). In fact, in the 23 cases of recurrence reported, 16 of which were successfully treated conservatively again[15,18,25-28]; seven cases of recurrence underwent surgery[12] and only two cases occurred after a previous NOM[25,28].

Eastern studies also show similar recurrence rate (1%-20.5%) after conservative management both for uncomplicated and recurrent RCD[54-56].

Zuckerman et al[28] also show a lower recurrence rate after ARCD compared with ALCD (4.1% vs 32.8%).

Furthermore, according to the analysis of Imaeda et al[1], there are fewer complicated RCDs than liver cancer domains (LCDs). In fact, the complication rate was also low (10.66%), with only 1.66% of major complications according to Clavien Dindo (CD) classifications (six reported CD 3 complications and only one CD4)[12,22,23,25].

A very important aspect was demonstrated by Courtot et al[25]as the recurrence rate was low and similar for both complicated and uncomplicated ARCD (6.8% and 8.8%, respectively) demonstrating the benign course of this condition.

Furthermore, in the Zuckerman et al[28] study it is shown that 5% of patients with an initial diagnosis of RCD subsequently developed colon cancer. And being a higher rate than average-risk[57], an endoscopic screening program for these patients could be scheduled.

Confront vs east

Although the incidence of RSD is much higher in Asian countries, we have not found specific guidelines. Nonetheless, several authors have published studies showing their management for this condition.

For example, in two important studies the authors show that most cases of ARCD are uncomplicated (78.5% and 92.8%) and that they are successfully treated conservatively (reaching as much as 98% of cases)[58,59]. NOM is also effective in 41.7% of complicated ARCD (cARCD), reserving surgery only in the remaining cases and making it possible to convert an urgent intervention into an elective one.

In support of the efficacy of conservative treatment, two recent meta-analysis show similar results. In particular, they show a low recurrence rate after uncomplicated ARCD (10.9% and 12%). The first study[60] focused on the fact that only 4.4% of recurrences were complicated and there was only a 1.7% of re-recurrence rate. While the second[61] showed that only a small percentage of patients underwent surgery after recurrence (9.9% as urgent cases, 5.4% as elective cases). Both authors conclude that NOM is safe and feasible for Hinchey 1b-2 stages, similarly to the management of uncomplicated left-sided diverticulitis, while surgery should only be performed in selected cases.

The effectiveness of the NOM is even the background from which the authors started to design a prospective randomised controlled trial (RCT). Kim et al[62] compared the conservative treatment of uARCD with or without antibiotic obtaining similar results regarding to treatment failure rates (4.7% vs 1.6%), length of hospital stay and recurrence rate (7.8% vs 9.8%). Moreover, the group without antibiotics was burdened by a lower cost.

In the only recent study that defends the surgical approach, Luu et al[63] stated that laparoscopic diverticulectomy could be offered to selected patients (younger patients, who live in remote areas or with higher risks of recurrence). The author points out that, compared to conservative management, minimally invasive approach has similar outcomes in terms of complications (12.2% vs 8.6%) and treatment failure (13.5% vs 9.9%) and with a lower recurrence rate (0% vs 16.6%).

In this regard, there is some confusion on the main predictors of recurrence. In another study, multiple diverticula were found to be the main reason[64]. But this result seems to be disproved in the aforementioned RCT of Luu et al[63] in which fever and markers for inflammation were predictive, instead[62]. Other predictors were young age and longer duration of symptoms before hospital admission[65].

CONCLUSION

The management of ARCD remains a great challenge for surgeons. Although recent updates of WSES guidelines suggest that all the statements for ALCD may also apply to ARCD, several topics need to be investigated. Lack of diagnosis is the most important problem and CT scan seems to be the best imaging modality. NOM remains the preferred treatment in uncomplicated cases, whereas surgery should be considered in unstable patients or complicated disease. Laparoscopic approach should be offered whenever it is feasible. Further studies are needed in order to understand epidemiology, diagnosis and optimal management of this rare condition.

This review underlines the importance to collect more data, especially in western countries, to understand if it’s a condition more common than we thought, and if we really need more selective guidelines or we can simply apply the principles already proposed for left side diverticulitis.

ARTICLE HIGHLIGHTS

Research background

Right sided diverticulitis is very frequent in Asian countries, while in western countries it has always been considered very rare. On the other hand, in recent studies, the condition has been shown to be increasing in recent years.

Research motivation

Despite this rapid spread, there are no clear guidelines on the management of RSD. Until now, their management has been based on knowledge gained from left sided diverticulitis.

Research objectives

The authors therefore wanted to analyze the studies in the literature to have a broader and deeper point of view to understand what could be the correct management.

Research methods

The authors analyzed the articles from western countries starting from 1990 in which the management and the subsequent outcome of right sided diverticulitis were shown.

Research results

The authors found that most cases of right colonic diverticulitis are treated effectively with non-operative management, reserving surgical treatment especially for complicated cases. Recurrences have a low rate and are also successfully treated conservatively.

Research conclusions

Right sided diverticulitis has a similar management in both western and Asian countries.

Research perspectives

Further studies will serve to identify more precisely which cases should be reserved for surgical treatment.