**2. Discussion**

Laparoscopic sacrocolpopexy with synthetic mesh is an effective treatment option for POP with success rates ranging from 78 to 100% [49, 52]. Manufacturer data shows that synthetic mesh can induce an inflammatory process that can result in fibrosis and scarring, distorting normal anatomy and changing the mesh characteristics [45]. Mesh exposure after POP or SUI procedures ranges from 2 to 30% [52], with reoperation rate of 7.9% for apical and 12.7% for other compartments repair as per Cochrane review [51]. Infected and/or exposed mesh can erode into nearby bone and periostium and cause osteomyelitis. Jenson's report states that lumbosacral osteomyelitis and discitis usually occur by hematogenous spread but can also occur from direct inoculation after SCP when bone anchors or permanent sutures are inadvertently placed too deep into the L5-S1 disc space. Mesh exposure is also associated with chronic cigarette smoking, which may have had significance for the patient of Case 1 [53]. Osteomyelitis has been reported to have a median time of presentation of 4 months following a POP procedure [8, 32]. Our cases show that it can present up to 10 years later.

In 1997, Amid et al. classified mesh into different types. Type I mesh are monofilament, flexible and light-weight. They are recommended for most pelvic organ reconstructive procedures because their large pore size greater than 75 mcg allows for tissue integration and for immune cells to scavenge bacteria [54, 55]. Examples are polypropylene Restorelle mesh (used in Case 1), Gynemesh (used in Case 3), Atrium, and Marlex. Type II are microporous with pores less than 10 mcg, such as Gore-Tex (used in Case 2). Type III are microporous but with macroporous components, and type IV mesh are nonporous such as Silastic, Celligard, and Preclude [54, 55]. There lacks a clear recommendation on how to proceed with mesh exposure, especially for type I mesh. These cases add to the available literature regarding different types of mesh, their delayed complications, and treatment suggestions.

All data clearly shows that surgery is necessary when conservative measures fail, when there is high suspicion for severe osteitis, or when repeat mesh revisions are not successful. Surgery can occur via transvaginal excision, endoscopic assisted transvaginal excision, open laparotomy, or by minimally invasive intraperitoneal laparoscopic or robotic surgery. A literature review on the topic reveals no standard protocol for osteomyelitis related to POP-mesh [52, 56–58]. In February 2020, American Society of Obstetrics and Gynecology (ACOG) and International Urogynecological Association (IUGA) published a Joint Position to guide the management of mesh complications [57, 58]. Asymptomatic mesh exposure after SCP can be observed (Grade C recommendation) while understanding that three of four exposures will not resolve and may require surgery [57], which heals 93% of patients [59]. Similarly, Abbott et al. demonstrated that 60% of patients with mesh exposure need at least one surgical intervention to remove the mesh [60]. The 2019 National Institute for Health and Care Excellence recommends surgical intervention after 3 months of conservative management [57].

The patient of Case 1 underwent a trial of conservative management with antibiotics, however she required surgery once her clinical status acutely worsened. This patient became medically compromised, developed focal neurological deficits and her infection fistulised resulting in copious malodorous vaginal discharge leading to perineal excoriation.

Cases 2 and 3 presented patients requesting definitive surgical management after prior multiple failed mesh revisions attempts. Partial removal of mesh and the involved vaginal epithelium may be adequate for cases of limited vaginal exposure without pain (Grade D recommendation). However, office trimming with or without estrogen has a 75% risk of failure [18, 57, 61]. Repetitive trimming in the office is not recommended since it can distort the anatomy further (Grade D recommendation). According to the Joint Position, those who undergo surgical revision rather than office based trimming will still need additional surgery or complete excision in 37–50% of cases (Grace C recommendation). Focal vaginal pain without mesh exposure may require surgery if conservative measures are unsuccessful [57]. About 50% of patients undergoing mesh revision are successfully treated, but most require an abdominal surgery, and 25% require more than one surgery [57]. For persistent mesh-related pain, 50% of women with silicone mesh who attempt vaginal-specific repair ultimately need complete abdominal excision [57]. Cases 2 and 3 required complete intraperitoneal access removal of infected mesh after prior vaginal resection failures.

All above cases developed pelvic abscesses. Although there are reports of abscesses successfully managed by drainage alone (Grade C), these cases occurred within 14 days of SCP surgery [57]. Data is lacking for abscesses with delayed presentation, for which we recommend surgical intervention when conservative or partial-surgical interventions fail, or when severe symptoms persist. In those cases entire mesh must be removed. Similar to case 2 and 3 Unger et al. published a case of Gore-Tex soft tissue patch case that subsequently need complete removal after prior failed surgical attempts to partially remove it [24]. Our cases differ due to their prolonged interval from mesh placement to the time of osteitis. In these situations, surgeons should expect a chronically inflamed, distorted surgical field and must plan in advance to have different specialists equally involved and readily available.

In a patient with back pain and a history of SCP mesh, osteitis should be high on the differential given that 85% of SCP-osteitis cases present with back pain [62]. Physical exam with MRI of the lower spine is the gold standard for diagnosis [62]. Cultures can be helpful in directing targeted antibiotic therapy. Although some reported cases have responded to antibiotics alone (Grade I recommendation), most cases need multidisciplinary surgical team (Grade B recommendation), as this could be a life threatening condition [62]. The 2015 Infectious Disease Society of America (IDSA) recommend image-guided aspiration biopsy for patients with suspected vertebral osteomyelitis except when S. Aureus, S. Lugdunensis, or Brucella species are grown from blood cultures. However Jenson et al. recommends immediate empiric antibiotics to prevent infection along the spine [62]. Pathogens most commonly identified are staphylococcus and streptococcus, however fecal contamination may also be present in cases where a fistula is involved. Serratia Marcescens (SM) is a rod-shaped Gram-Negative facultative anaerobic, a rare bacterium that can cause osteomyelitis, particularly associated with IV recreational drug use or nosocomial infections [13]. SM fimbriae allow it to grasp onto surfaces, and its proteases enable it to thrive in anaerobic and aerobic environments [14]. Being intrinsically resistant to several beta-lactam antibiotics, first-line agents are instead Piperacillin-Tazobactam, a fluoroquinolone, an aminoglycoside, or a Carbapenem [14]. The regimen can then be tailored to susceptibility results. Given the nature and extent of infection, treatment requires 6–8 weeks of IV antibiotics, with most

patients subsequently prescribed oral antibiotic therapy for a total duration of 12 weeks [8, 32, 63]. Case 2 demonstrates the aggressiveness of SM in the context of hospital-acquired infection, as it indolently grew and weakened the abdominal fascia causing incarcerated central hernia. This patient required a wound vacuum skin closure to allow repair sites to heal by secondary intention.

In presence of a severe infection, impaired mental capacity of elderly women may limit the ability to differentiate dementia from worsening sepsis. Individuals with history of POP mesh repairs with pain, abnormal vaginal discharge or bleeding discitis should have osteomyelitis high on the list of differentials and antibiotics should be initiated promptly if warranted. Consultation of FPMRS specialist familiar with above presentation along with physical exam and pelvic MRI helps for prompt diagnosis [53, 57]. Large mesh exposures, infection, severe symptoms, or involvement of bladder, bowel or bone require complete excision, understanding that complete removal of infected mesh from the posterior cul-de-sac in vicinity of the bladder and presacral space requires intra-abdominal access [57, 61]. Special attention must be paid to the bladder, ureters, rectum, and vagina, as well as the great pelvic vessels, particularly the left common iliac vein and its confluences or malformations. Although vaginal mesh complications have been well publicized, complications from intra-abdominal mesh placed by means of MIS for POP repair are limited. Compared to vaginally placed mesh, MIS intra-abdominal mesh is also more durable, however it carries its unique risks associated with general anesthesia, Trendelenburg positioning and pneumoperitoneum [42]. Otherwise, the unique risks are poorly published, with osteomyelitis only reported in several cases. There is limited guidance on how to approach an abdominal mesh complication. Expectant management can begin with antibiotics. Surgery is recommended if clinical status acutely worsens, symptoms are severe, if the patient has failed multiple attempts at mesh revision, or with new onset neurological deficits [18, 57, 61]. Although G. Willy Davila's report provides recommendations for managing small vs. large vaginal mesh exposures as well as its contractions and infection [50], Level I evidence are still lacking on how to manage infected mesh deep in the sacral region.

### **3. Conclusion**

This case series presents an example of three patients who underwent open abdominal, laparoscopic and robotic POP repair several years prior, and subsequently developed mesh related osteomyelitis requiring complete removal of mesh. Of particular significance is the delayed onset of osteitis presenting up to a decade after mesh placement. This can be a challenge when patients are not the best historians either due to advanced age or other comorbidities. With an increased demand for POP prolapse surgeries as the population ages, mesh-related osteomyelitis will become more prevalent. Prospective randomized studies could help determine the ideal protocols for treatment of foreign body osteomyelitis. This short case series illustrates that mesh-related osteomyelitis after POP surgeries carries significant morbidity, its management can be technically challenging and should not be undertaken lightly. However it also demonstrates that mesh removal by means of MIS in the hands of an experienced surgical team utilizing DaVinci Robotic System is a good option and may be the preferred option among these challenging patients [52, 56].

*From Open to Minimally Invasive: The Sacrocolpopexy DOI: http://dx.doi.org/10.5772/intechopen.101308*
