Complications of Female Incontinence and Pelvic Reconstructive Surgery (Current Clinical Urology) 2nd ed.

1. Taxonomy of Complications of Pelvic Floor Surgery

Roger R. Dmochowski Alex Gomelsky2 and Laura Chang-Kit1


Department of Urologic Surgery, Vanderbilt University School of Medicine, A-1302 Medical Center North, Nashville, TN 37232, USA


Department of Urology, Louisiana State University Health Sciences Center, Shreveport, Shreveport, LA, USA

Roger R. Dmochowski



The etymology of the word “taxonomy” is from the Greek taxis, meaning orderly arrangement, and nomos, meaning law. Steadman’s Medical Dictionary defines “taxonomy” as the systemic classification of living things or organisms, and, more recently, the term has come to mean any specialized method of classifying objects or events. In the scientific community, taxonomies have proven to be highly efficient structures for organizing vast amounts of content. Taxonomy, as it relates to surgical complications, is a relatively novel concept. Intuitively, the idea to organize complications for ease of comparison and to assist in risk stratification is a noble one. However, if improperly designed, classification systems may be cumbersome to use and may not be widely adopted. In this chapter, we explore the details behind taxonomy development in the surgical and urological literature and assess their potential for implementation in pelvic reconstruction procedures.


The etymology of the word “taxonomy” is from the Greek taxis, meaning orderly arrangement, and nomos, meaning law. Steadman’s Medical Dictionary defines “taxonomy” as the systemic classification of living things or organisms, and, more recently, the term has come to mean any specialized method of classifying objects or events. In the scientific community, taxonomies have proven to be highly efficient structures for organizing vast amounts of content. Taxonomy, as it relates to surgical complications, is a relatively novel concept. Intuitively, the idea to organize complications for ease of comparison and to assist in risk stratification is a noble one. However, if improperly designed, classification systems may be cumbersome to use and may not be widely adopted. In this chapter, we explore the details behind taxonomy development in the surgical and urological literature and assess their potential for implementation in pelvic reconstruction procedures.

The Need for Taxonomy of Complications

Complications are an essential aspect of performing surgery. They are usually multifactorial and may accompany even the least-invasive and routine procedures. Complications reported in the surgical literature can also serve as vital outcome measures and valuable quality indicators. Traditionally, however, the reliability of reporting complications has been inconsistent. Martin et al. developed a list of ten critical elements of accurate and comprehensive reporting of surgical complications [1]. These criteria included providing the methods of accruing data, duration of follow-up, outpatient information, definition of complications, mortality rate and causes of death, morbidity rate and total complications, procedure-specific complications, severity grade, length-of-stay data, and risk factor included in the analysis. Out of 119 articles reporting outcomes in 22,530 patients that underwent pancreatectomy, esophagectomy, and hepatectomy, no article reported all ten criteria and only 2% reported nine of ten. The most commonly unmet criteria were outpatient information (22%), definitions of complications provided (34%), severity grade used (20%), and risk factors used in analysis (29%). Reporting of complications in the urologic literature has been similarly inconsistent. In a MEDLINE search encompassing 109 studies and nearly 150,000 patient-­outcomes following radical uro-oncologic surgical procedures, Donat found that only 2% of the studies met 9–10 of the ten established criteria for surgical complication reporting [2]. The most commonly underreported criteria were complication definitions in 79%, complication severity and/or grade in 67%, outpatient data in 63%, comorbidities in 59%, and the duration of the reporting period in 56%. Certainly the disparity in the quality of complication reporting makes it nearly impossible to compare the morbidity of surgical techniques and outcomes.

Depending on the type of procedure and definition of complication, the prevalence of complications in reconstructive pelvic surgery varies significantly. In a retrospective review of 100 consecutive reconstructive cases, Lambrou et al. reported a complication prevalence of 46%, which included 13 intraoperative complications and 33 postoperative complications [3]. The readmission rate for complications was 15%. The number of procedures per patient was an independent risk factor for intraoperative blood loss, while blood loss was an independent risk factor for perioperative complications. The prevalence of complications in midurethral sling (MUS) surgery appears to also vary significantly [4]. In a systematic review and meta-analysis of randomized, controlled trials (RCTs) comparing various MUS procedures, Novara et al. reported bladder penetration rates ranging from 0 to 24%. Rates of hematoma formation, bladder erosion, and vaginal extrusion were 0–16.1%, 0–13.1%, and 0–5.9%, respectively. Postoperative urinary tract infections (UTIs) were reported in up to 17.8% of women, while the rates of postoperative storage lower urinary tract symptoms (LUTS) and voiding LUTS were 0–41.3% and 0–55.1%, respectively. It must also be noted that a large portion of the evaluated RCTs had no available data for several of the complication categories mentioned above. Likewise, in a meta-analysis of surgical procedures for repair of pelvic organ prolapse (POP), Maher et al. noted that the impact of surgery on associated bladder, bowel, and sexual function symptoms was poorly reported in 40 RCTs reporting on over 3,700 women [5]. When reported, complications such as intraoperative blood loss and the rates of persistent, worsened, or de novo LUTS varied widely, making comparisons of studies even more challenging.

The reporting of complications in surgery, and reconstructive pelvic surgery in particular, may be inconsistent for several reasons. First, a complication by one surgeon’s consideration may not be seen as one by another surgeon and, thus, may not be consistently reported. Second, specific cutoff values for outcome criteria such as estimated blood loss and postvoid residual volume are not universally agreed upon, further complicating the reporting of these sequelae. Third, studies in the past have often focused on anatomic outcomes, such as resolution of stress urinary incontinence and improved POP grade following repair. It appears that only in the last several years surgeons have developed an increasing appreciation of subjective outcomes, or those having a significant impact on quality of life (QoL). Similarly, the acceptance of subjective complications such as pelvic pain and dyspareunia continues to evolve.

The connection between quality and health care delivery has recently taken a forefront in the public eye. The Office of the Inspector General Work Plan for Fiscal Year 2011 describes at least seven items focusing on quality data for hospitals and providers, such as readmissions, adverse events, and responses to adverse events. Likewise, Title III of the Patient Protection and Affordable Care Act of 2010 (PPACA) is entitled “Improving the Quality and Efficiency of Health Care.” The name summarizes the framework in which quality is considered as part of health care reform and becomes intimately connected with payment. Despite the obvious Federal focus on quality improvement initiatives, there appear to be obstacles to reporting of complications. Studies have shown that physicians often underreport the incidence of serious complications associated with surgery [67]. Another study found that the reporting of complications associated with MUS placement in the U.S. Food and Drug Administration (FDA) manufacturer and user faculty device experience (MAUDE) database significantly exceeded the complications reported in published literature [8]. One reason for underreporting may be that there is a clear lack of centralized registries of complications. Another may be that surgeons may view the reporting of complications as a stigma and may fear public embarrassment or professional retribution. Regardless of the potential reasons, it is clear that it becomes increasingly difficult for surgeons to learn from the experiences of others without accurate estimates and sources of complications. It also makes the process of informed consent even more tenuous.

Existing Classification Systems of Complications

As the classification of complications in pelvic reconstructive surgery is thus far in its infancy, valuable information may be gleaned from the general surgery literature. Clavien et al. first developed a distinction between three types of negative outcomes: complications, failure to cure, or sequelae [9]. Complications were defined as any deviation from the normal postoperative course, which also took into account asymptomatic complications such as arrhythmias and atelectasis. A sequela was defined as an “after-effect” of surgery that was inherent to the procedure. Failure to achieve a cure meant that the original purpose of the surgery was not achieved, even if the surgery was executed properly and without complications. What came to be known as the Clavien classification took into consideration only complications, and not treatment failures or sequelae.

The initial Clavien classification consisted of four severity grades and the current, modified classification is composed of five grades [10]. Grade I is any deviation from the normal postoperative course without the need for any pharmacological treatment or surgical, endoscopic, and radiological intervention. The allowed therapeutic regimens include replacement of electrolytes, physiotherapy, and medications such as antiemetics, antipyretics, analgesics, and diuretics. Wound infections that are opened at the bedside also fall into this grade. Complications falling into grade II require pharmacological treatment with medications other than such allowed for grade I complications. The requirement for transfusion of blood products and total parenteral nutrition also constitutes a grade II complication. Grade III complications require surgical, endoscopic, or radiological intervention. This category is subdivided into IIIa (not under general anesthesia) and IIIb (under general anesthesia). Grade IV complications are life-threatening and require intermediate or intensive care management. Central nervous system complications such as brain hemorrhage, ischemic stroke, and subarachnoid bleeding are included in this category, while transient ischemic attacks are not. This category is also subdivided into IVa (single-organ dysfunction, with or without dialysis) and IVb (multiorgan dysfunction). Death of a patient is a grade V complication. The suffix “d” (for “disability”) is added to the respective grade of complication if the patient suffers from a complication at the time of discharge. This label indicates the need for a follow-up to fully evaluate and stage the complication.

The key to ranking the complications using the modified Clavien system is the intricacy of the treatment used to correct the complication [10]. The authors validated this classification in over 6,300 patients undergoing elective surgery in their institution over a 10-year period. The complexity of surgery was estimated according to a modification of an established graduation and the authors found that the classification of complications significantly correlated with the duration of the hospital stay, a surrogate marker of outcome. A strong correlation was also found between the complexity of surgery (and assumed higher complication rates) and outcome of surgery as assessed by the novel, modified classification. The authors then conducted an international survey to access acceptability and reproducibility of the classification. Over 90% of the surgeons queried found the classification to be simple, reproducible, and logical. These surgeons stated that they would support the introduction of the classification into their clinical practice.

The modified Clavien classification has thus far been employed in classifying complications in several urologic surgical applications, including radical cysto-urethrectomy, percutaneous nephrolithotomy, live donor nephrectomy, laparoscopic radical prostatectomy, and ureteroscopy [1115]. To date, the modified Clavien classification has not been rigorously evaluated in the milieu of pelvic reconstructive surgery.

Recently, a classification of complications directly related to the insertion of prostheses (meshes, implants, tapes) or grafts in female pelvic floor surgery has been introduced [16]. This report combined the input of members of the Standardization and Terminology Committees of two International Organizations, the International Urogynecological Association (IUGA) and the International Continence Society (ICS) and a Joint IUGA/ICS Working Group on Complications Terminology, and was assisted at intervals by many expert external referees. An extensive process of 11 rounds of internal and external review took place with exhaustive examination of each aspect of the terminology and classification. The decision-making process was conducted by collective opinion (consensus). The classification is based on category, time, and site classes and divisions. The category (C) is stratified by location of compromise (vagina, urinary tract, bowel or rectum, skin or musculocutaneous system, and hematologic or systemic compromise) and symptom severity (asymptomatic, symptomatic, presence of infection, and abscess formation). The timing of complication (T) is subdivided into four groups (intraoperative to 48 h, 48 h to 2 months, 2–12 months, and >12 months), while the site of complication (S) includes vagina (at or away from the suture line), due to trocar passage, other skin or musculoskeletal site, and intra-abdominal location. Additionally, grades of pain may be assigned as a subclassification of complication category. The subjective presence of pain by the patient only may be graded from a–e (asymptomatic or no pain to spontaneous pain). Each complication is assigned a CTS code consisting of three or four letters and four numerals and should theoretically encompass all conceivable scenarios for describing insertion complications and healing abnormalities.

The Challenge of Implementing a Classification System of Complications

Inherent to the definition of taxonomy is that the classification system should reduce complexity by suggesting a logical and hierarchical representation of categories. The classification should likewise provide a means for organizing and accessing vast quantities of data in an intuitive manner. Unfortunately, the adoption of classification systems in pelvic reconstructive surgery has not, to date, been encouraging. The Pelvic Organ Prolapse Quantification (POP-Q) system is a prime example.

While classification systems for pelvic organ support have existed since the 1800s, no system has gained consistent and widespread acceptance [17]. Over the past 20 years, the POP-Q has become the first and only classification system to be recognized by the ICS, the American Urogynecologic Society (AUGS), and the Society of Gynecologic Surgeons (SGS) [18]. This system has been extensively studied and excellent inter- and intraobserver reliability have been demonstrated [1920]. Although the POP-Q is arguably the only universally accepted classification system for grading the severity of POP, it has not been universally adopted. As of 2006, the POP-Q has been used clinically by only 40% of the members of ICS and AUGS, the groups that acknowledge this system as the classification standard for POP [21]. Some of the reasons given by clinicians surveyed for not consistently employing the POP-Q were that the system is too confusing, overly time-consuming, and that it was not being used by their colleagues [21]. While some of these reasons are not supported by literature [19], it remains that even the most rigorous and well-conceived classification systems may not achieve widespread use owing to concerns regarding simplicity of use. Since, Swift et al. have validated a simplified POP-Q system to address the concerns that the traditional POP-Q is not a “user-friendly” classification system [22].

The novel classification system proposed by IUGA/ICS, while comprehensive, may be cumbersome to use and does not immediately appear to reduce the complexity of organizing complications. Furthermore, the CTS classification does not leave room for reporting the presence of de novo or worsened storage or voiding LUTS commonly associated with surgery for stress urinary incontinence. The modified Clavien classification, while simpler to integrate, appears to be constructed for grading surgical procedures with a significant prevalence of postoperative intervention, reoperation, and morbidity. It can certainly be argued that, since pelvic reconstructive surgery is often performed in otherwise healthy individuals, it is associated with an overall low prevalence of significant morbidity. Thus, the modified Clavien classification may not be sensitive enough to classify the complications typically associated with pelvic reconstructive surgery.

Complications in urologic pelvic surgery may be classified as general or specific, by their temporal relationship to the surgery itself and by their relationship to a technique or specific material used in the procedure. These are summarized in Table 1.1. Taking into account these complications, we propose a modification of the Clavien classification constructed specifically for complications associated with pelvic reconstructive surgery (Table 1.2).

Table 1.1

Common complications in pelvic reconstructive surgery






Acute bleeding


Hematoma drainage




Organ injury


Repair organ injury


Pneumonia, atelectasis




Arrhythmia, MI, CVA, PE, DVT, death


Postoperative <30 days

MI, CVA, PE, DVT, death

Incisional pain

Pelvic pain



Wound infection


Leg pain

Storage LUTS

Voiding LUTS


Erosion into GU tract

I&D wound

Sling revision

Sling/mesh revision

Postoperative >30 days

Incisional pain

Pelvic pain

Storage LUTS

Voiding LUTS



Erosion into GU tract

Leg pain

Sling/mesh revision

MI myocardial infarction; CVA cerebrovascular accident; PE pulmonary embolism; DVT deep vein thrombosis; UTI urinary tract infection; I&D incision and drainage; AUR acute urinary retention; PSBOpartial small bowel obstruction; LUTS lower urinary tract symptoms; GU genitourinary

Table 1.2

Proposed pelvic reconstructive surgery modification of the Clavien system





Deviation from normal course (no need for additional intervention)

Trocar bladder puncture, replaced; no formal repair

Perioperative antipyretics

Postoperative pelvic floor exercises


Pharmacological intervention (other than for Grade I)

Antibiotics for UTI or wound infection; antimuscarinics

Transfusion of blood products

Analgesics for incisional, pelvic, or leg pain


Short- or long-term complication, no operative intervention

De novo or worsened storage LUTS

De novo or worsened voiding LUTS

Incisional, pelvic, or leg pain


Operative intervention required

IVa: Intraoperative/immediately postoperative

IVb: Postoperative, office

IVc: Postoperative, operating room

Repair organ injury (bladder, ureter, colorectal, vascular); endovascular embolization for bleeding

Incision and drainage wound infection; partial excision extruded sling/mesh

Sling/mesh incision/revision/excision; urethrolysis; laparotomy for small bowel obstruction; InterStim


Life-threatening event or demise

Va: Single-organ dysfunction

Vb: Multiorgan dysfunction

Vc: Death


UTI urinary tract infection; LUTS lower urinary tract symptoms; DVT deep vein thrombosis; PE pulmonary embolism; MI myocardial infarction; CVA cerebrovascular accident; CNS central nervous system event; InterStim sacral neuromodulation


A taxonomy for the classification of complications in pelvic reconstructive surgery would be a valuable instrument for reporting outcome measures and quality indicators. While both the modified Clavien classification and the recent IUGA/ICS classification contain valuable components, at present, a single, comprehensive, user-friendly system does not exist. The determination of an optimal classification system would lead to an improved ability of surgeons to communicate with each other and compare data.



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