There are several types of malignancies that may involve the pelvic structures, such as gynecological cancer (ovarian, cervical, endometrial), rectal or bladder cancer and other rarer causes and mimickers. For ease of reading, we will refer to all of them below as “pelvic cancers”. Surgical techniques along with radiotherapy and chemotherapy have increased the survival of patients with pelvic cancers, while increasing the importance of their quality of life (QOL) ^[1][2][3][4][21,22,23,24].

Urinary incontinence and overactive bladder are both pathological conditions that have a high prevalence after pelvic surgery and are known to greatly impair QOL. Urinary incontinence particularly affects women, causing adverse physical, emotional, and social effects ^[5][6][25,26]. The prevalence of urinary incontinence after a pelvic surgery for cancer, ranges between 24–52.4% ^[7][8][27,28], with no reported differences regarding the primary cancer site.

There are two categories of patients with urethral meshes: (1) patients with mesh who may develop a pelvic cancer, and (2) patients with a pelvic cancer and post-surgical urinary incontinence treated with urethral meshes.

For the first category of the patients, in addition to highlighting tumour invasion into adjacent structures, MRI is able to highlight how the cancer affects the urethral mesh, its location, structure and possible complications (Figure 16, Figure 27 and Figure 38).

For the second category of patients treated for a pelvic cancer, MRI is usually used to detect tumour recurrence and short- and long-term mesh complications.

Complications associated with urethral mesh procedures can occur, but their frequency can vary depending on several factors, including the specific procedure, patient characteristics (including the onset of a pelvic cancer), and the experience of the surgeon. It is important to note that the complication rates can vary depending on the length of follow-up and the definition and reporting of complications across different studies ^[9][29]. However, it is generally accepted that two main types of complications can occur: short-term and long-term, both of which also affect cancer patients.

Short-term complications include intraoperative and immediate post-operative complications related to injuries during surgery, acute urinary retention and infections ^[10][11][30,31]. Depending on the mesh pathway we may encounter bladder, urethral or bowel injuries in up to 24% of the TVT, and obturator nerve and artery lesions in up to 2% of the TOT patients ^[12][32] (Figure 49, Figure 510 and Figure 611).

The reported rates of acute urinary retention (AUR) following urethral mesh placement have ranged from between 2% to 12% ^[13][14][15][33,34,35]. However, it’s important to remember that these rates can vary depending on the specific procedure, patient population, the follow-up period of the study and different causes. Several factors can contribute to the development of AUR, such as post-operative swelling, overactive bladder, temporary dysfunction of the bladder muscle or nerves, excessive mesh tension or malpositioned tape sitedtoward the urethra-vesical junction. It is worth mentioning that AUR is often a transient complication and can be managed with conservative measures, the temporary use of a catheter and only in a minority of cases is surgery required.

It is important to note that the occurrence of infection can be influenced by factors such as the patient’s overall health, pre-existing conditions, adherence to sterile techniques during surgery, and post-operative care.

The reported rates of infections in the early post-operative period following urethral mesh procedures have ranged from less than 1% to around 10% ^[16][17][17,36]. Infections can manifest as urinary tract infections (UTIs) or surgical site infections. UTIs are more common, present with symptoms such as increased urinary frequency, urgency, burning sensation during urination, lower abdominal/ pelvic discomfort and have a conservative treatment. Surgical site infections can cause redness, swelling, warmth, pain, or discharge at the incision site and usually require imaging to assess the depth and the local extent of the disease (Figure 712).

Inflammation and infections of urethral meshes are easily depicted on thin T2WI slices, as having thickened uni- or bilateral limbs with high signal intensity. Abscesses may affect any portion of the mesh and therefore requires evaluation of the trajectory of the mesh in all planes. Infected or inflammed mesh appears with avid enhancement on post-contrast sequences, helping identifing the sinus trast and abscesses (Figure 813 and Figure 914).

Delayed-postoperative complications range from 3–25% of cases and include bladder outlet obstruction, urinaryx incontinence and recurrent urinary tract infections in the majority of the cases; while only 2–3% of these are related to mesh integrity and/or abnormal localization ^[16][17][18][17,36,37]. Of the latter, the most common complications are mesh exposure/erosion and extrusion, and may lead to reccurent urinary infections or irritative pelvic simptoms. Whenever a mesh lesion is clinically suspected, we suggest performing a dedicated MRI for assessing mesh integrity, while also acknowledging the potential utility of ultrasound.

Erosion or exposure of the mesh usually involve vagina, urethra or bladder, and are recognised when the mesh limbs are seen within the lumen of these sturctures ^[19][16]. The involved mesh limb will be thicknened with high T2WI signal intensity and mild- to avid- enhancement on post contrast sequences.

In many cases, inflammation and infection occurring late after surgery secondary to mesh erosion, particularly involving the vagina. Surgery may be needed to remove the affected limb or entire mesh or correct other complications, although the overall incidence is rare. Over 50% of women who experienced erosion with non-absorbable synthetic mesh needed to have the mesh surgically removed. Some patients required two or more operations after the mesh was removed (Figure 105, Figure 116, Figure 127, Figure 138).