Prof. Dr. Robert Rosenberg, FACS, EMBA, is a recognized expert in the fields of general and visceral surgery as well as oncologic surgery. As Head of the Department of General and Visceral Surgery at the Kantonsspital Baselland in Liestal, he also leads the certified Colorectal Cancer Center, one of the leading institutions of its kind in Switzerland. His clinical focus lies in treating gastrointestinal tumors, particularly colorectal and rectal cancer, as well as benign diseases of the colon and rectum.
With comprehensive training completed both at the Klinikum rechts der Isar in Munich and at renowned hospitals in the United States, Prof. Dr. Rosenberg possesses deep international surgical expertise. His specialties include minimally invasive surgery, robot-assisted procedures using the Da Vinci system, laparoscopic surgery, and traditional open surgery. All procedures are tailored to the individual patient’s situation and follow current national and international guidelines.
In tumor surgery, Prof. Dr. Rosenberg aims to ensure oncological safety through precise surgical techniques while preserving patients’ quality of life. He combines surgical precision with compassionate patient care and plays a key role in maintaining the highest standards of visceral surgical care in the Basel region and beyond.
In a conversation with Prof. Dr. Rosenberg, the editorial team at Leading Medicine Guide learned more about the treatment of diverticulitis.
Diverticulitis is an inflammatory disease of the colon in which small pouches in the intestinal wall, known as diverticula, become inflamed. These changes occur most commonly in the sigmoid colon, the lower part of the large intestine, and are widespread in Western industrialized countries. While many people have diverticula without symptoms, diverticulitis can suddenly cause severe abdominal pain, fever, and changes in bowel function. The condition is influenced by several factors, such as a low-fiber diet, age, or genetic predisposition. In most cases, diverticulitis can be treated conservatively, but in recurrent or complicated cases, surgery may become necessary.
The development of diverticula in the colon is influenced by various factors, with mechanical, dietary, and age-related components playing a key role.
“Diverticula occur most commonly in the sigmoid colon, a section of the large intestine located about 20 to 30 centimeters before the rectum. In Western countries, this is the area where diverticula are most frequently found and where inflammation most often arises. Whether and how diverticula form depends on multiple factors—some modifiable, others not. One of the most important non-modifiable factors is age: as we age, the elasticity and strength of the intestinal wall decrease, making diverticula more likely. It’s estimated that about 50 to 60 percent of people over the age of 70 have diverticula. However, younger individuals are increasingly affected today. Another unchangeable risk factor is genetic predisposition. Many patients report that their parents or grandparents were also affected—this familial connection has been scientifically confirmed, suggesting a hereditary component in the development of diverticula“, explains Prof. Dr. Rosenberg, adding modifiable factors:
“There are also modifiable lifestyle factors that can promote the development of diverticula. Chief among them is a low-fiber diet. People who consume little fiber are more prone to constipation, resulting in firmer stools, slower intestinal transit, and increased pressure on the intestinal wall. This not only facilitates the formation of diverticula but also raises the risk of inflammation due to stool accumulation in the pouches. A sedentary lifestyle, obesity, high consumption of red meat, and regular alcohol intake are additional risk factors that increase the likelihood of diverticula and complications. These factors may also help explain why younger people are increasingly affected. As for the widespread belief that individuals with diverticula should avoid tomato seeds, chili seeds, or nuts—this is no longer supported by current evidence. Although such recommendations existed in the past, today’s data and medical guidelines do not confirm a connection. These foods are now considered safe for people with diverticula. It's also important to note that many people have diverticula without ever experiencing symptoms. Only about 5 to 10 percent will develop diverticulitis in their lifetime. Therefore, diverticulosis—merely having diverticula—is not a disease. Symptoms typically only arise when the diverticula become inflamed“.
Uncomplicated and complicated cases of diverticulitis differ significantly in their clinical presentation, diagnostic requirements, and therapeutic strategies.
In uncomplicated diverticulitis, only the diverticula are inflamed, without serious complications like abscess formation, perforation, fistulas, or bowel obstruction. Typical symptoms include localized pain—usually in the lower left abdomen—mild fever, altered bowel habits, and general malaise. Diagnosis often involves a combination of medical history, physical examination, and imaging techniques such as ultrasound or CT scans, with contrast-enhanced CT being the gold standard for accurately assessing inflammation and disease severity.
“Acute uncomplicated diverticulitis typically does not require surgery—it is treated conservatively. While antibiotics are often prescribed quickly, there is now strong evidence that an episode can be managed without antibiotics, provided the patient has a stable home environment, is able to stay hydrated, consume light food, and ideally has a general practitioner who can provide close follow-up care. Outpatient treatment is then entirely feasible. In practice, however, antibiotics are still often prescribed because the severity of the inflammation is sometimes overestimated—this remains common practice. Likely, too many antibiotics are still being used, even though they aren’t always necessary. What matters most: if symptoms improve with conservative treatment, there's no reason for surgery. Surgery is only considered if the inflammation doesn’t subside. Outpatient treatment means plenty of rest, adequate fluid intake, pain management, and reduced activity. Stress likely plays a role too—so it's important to mentally decompress. In most cases, symptoms improve quickly under these conditions“, says Prof. Dr. Rosenberg.
With age, the prevalence of diverticula in the colon increases significantly, due in part to age-related changes in the intestinal wall structure and reduced connective tissue stability. Older patients also often show atypical or less pronounced symptoms, making diagnosis more difficult and increasing the risk of a complicated course.
In complicated cases, more serious conditions may arise, such as perforation with free air in the abdominal cavity, extensive abscesses, fistulas to other organs, or intestinal strictures. Symptoms are often more severe, including intense pain, high fever, signs of sepsis, or acute abdominal rigidity in cases of perforation. A more comprehensive diagnostic approach is required to quickly assess complications and determine the appropriate treatment. In addition to CT scans, guided abscess drainage and endoscopic monitoring may be used, although a primary colonoscopy is avoided during acute episodes to prevent perforation risk.
If surgery becomes unavoidable—such as when inflammation fails to subside or a bowel perforation occurs—the question naturally arises as to how the procedure is performed and what methods are used.
“Whenever possible, surgery is performed during an inflammation-free interval. Healing outcomes are significantly better in this case, and the risk of complications is lower. If surgery is necessary during active inflammation, such as in an emergency, minimally invasive techniques—commonly called keyhole surgery—are still used in most cases. This may be done laparoscopically or with the help of a surgical robot. The goal of surgery is to remove the inflamed section of the colon—typically about 20 centimeters. Ideally, the two healthy ends of the intestine are reconnected. Only in extreme emergency situations, where inflammation is too severe, might a temporary colostomy be necessary to allow the body to recover. In planned procedures, this is usually not required. Many patients are understandably anxious about surgery, especially about a possible stoma. Therefore, it’s crucial to carefully weigh the decision. In cases of chronic, recurrent diverticulitis, the pros and cons of surgery should be thoroughly discussed with the doctor. While complications can never be ruled out completely, the risk of poor healing of the intestinal connection is only about two to three percent in experienced hands. The major benefit of surgery is that removing the source of inflammation typically leads to lasting improvement. Patients generally no longer need repeated antibiotic therapy and enjoy a significantly improved quality of life. This planning reliability is particularly important for individuals with demanding jobs or frequent travel. Studies now clearly show: quality of life after well-executed surgery is often much higher than after recurrent conservative treatments. There remains a very low risk of recurrence, since the entire colon is not removed—only the part most prone to inflammation, usually 20 to 30 centimeters before the rectum, where intraluminal pressure is highest. That’s typically sufficient to eliminate symptoms long-term. In rare cases, diverticula may still cause issues elsewhere in the colon“, explains Prof. Dr. Rosenberg.
Following a successful surgery and hospital discharge, one question becomes paramount for patients: What can I do to prevent recurrence and support my long-term gut health?
Prof. Dr. Rosenberg recommends: “The recommendations after surgery closely mirror those that are relevant before the disease—but now they carry even more weight. Nutrition is key. A fiber-rich diet is essential to keep stools soft and support natural bowel movement. This means regularly incorporating fruits, vegetables, whole grains, legumes, and nuts into your diet. The goal is to reduce intestinal pressure, since excessive pressure plays a critical role in the development of diverticula and inflammation. To optimize the effect of fiber, sufficient fluid intake is vital—at least 1.5 liters of water per day are recommended. Only then can the stool remain soft and easy to pass. Managing risk factors is also part of aftercare. Reducing consumption of red meat and highly processed foods is advisable, as they may contribute to intestinal inflammation. A balanced, plant-based diet helps counteract these effects. Physical activity is equally important. Regular exercise stimulates bowel function and helps maintain a healthy weight—an important factor, since obesity increases the risk of recurrence. Another often-overlooked aspect is stress management. Chronic stress negatively impacts the immune system and inflammatory processes—including those in the gut. That’s why finding ways to relax—such as meditation, yoga, mindfulness, or personal stress relief techniques—can be helpful. Regular relaxation benefits not only the mind but also the digestive system. Finally, quitting smoking is a vital part of recovery. Smoking can impair intestinal blood flow and is suspected of promoting inflammation. Those who actively support their recovery can significantly improve their long-term intestinal health with these measures“.
There is currently no direct link between diverticulitis and colorectal cancer—diverticula or flare-ups do not themselves cause cancer.
“However, it’s important to remain vigilant after a bout of diverticulitis. In clinical practice, we observe that individuals with a history of diverticulitis are slightly more likely to develop colorectal cancer than the general population. This suggests shared risk factors—related to diet, environment, or lifestyle—that may contribute to both inflammation and malignancy. That’s why we routinely recommend a colonoscopy four to six weeks after acute symptoms subside. This allows early detection and removal of polyps or other abnormalities. If symptoms are ignored or left untreated for too long, the inflammation may become chronic and lead to complications—such as fistulas, which are abnormal connections between the bowel and neighboring organs like the bladder. Abscess formation is also possible—a walled-off collection of pus, often caused by a partial bowel perforation contained by the body. Such complications always require inpatient treatment with antibiotics. If the abscess is large, it’s typically drained under CT guidance. Afterwards, the possibility of surgery can be discussed—not during the acute phase, but as a planned procedure focused on safety and healing“, adds Prof. Dr. Rosenberg.
Diverticulitis is one of the most common abdominal conditions leading patients to emergency rooms.
“At our clinic, we see people almost daily presenting with the classic symptoms—pain in the lower left abdomen, fever, or digestive issues. In many cases, we can quickly determine after the initial assessment whether hospitalization is necessary or if outpatient care is sufficient. This decision is made individually—depending on the severity of the inflammation, the patient’s overall condition, and available support. As a clinic specializing in intestinal surgery, we not only manage acute flare-ups conservatively but also regularly perform surgery when needed—whether due to recurrent inflammation or urgent complications. We perform several such procedures each week, which underscores how widespread and clinically relevant this condition is“, concludes Prof. Dr. Rosenberg.
Thank you, Prof. Dr. Rosenberg, for these valuable insights!
