Did you know that there are over 3,500 different species of mosquitos?¹ It’s the beginning of mosquito season in Iowa City, and our neighborhood entomology-hobbyist shared that fact with me as we enjoyed our first outdoor, mask-free beer together in over a year, among hundreds of thousands of newly hatched, hungry, blood-sucking Culicidae family members. I thanked him for the information, swatted another one with my Homo sapiens hand, and then told him I was really just interested in ways to stop them from biting my ankles. Another beer later and I’m ankle deep in mosquito taxonomy and learning about how only a few genera, namely Anopheles gambiae complex, are vectors for Plasmodium falciparum, the parasite responsible for human malaria—and how the Gates Foundation is funding research to genetically modify this complex to stop reproduction with the goal of eventually wiping out malaria.² Awesome.

This conversation forced an existential question: What if this friend, a lawyer, skeptical by nature and trade, came into my clinic with a urethral stricture? He might want to know answers to very basic, nonmalaria eradicating questions. For example, “Why do I have my urethral stricture?” Well, mostly we don’t know, unless you have lichen sclerosus, in which case, we really don’t know. “How are you going to treat my stricture?” Well, if you’re lucky, I’ll be able to just cut out the “bad” stuff and sew the “good” stuff back together. “So, what if I’m unlucky?” No big deal, really. We’ll just use some skin from your mouth or your penis or your rectum, then sew it to the unhealthy ends that we couldn’t cut out. “How well does that work?” Well, that depends on what you mean by “work.” “I mean, will it cure me?” Ha! Oh, you’re serious? No. We don’t really cure strictures. We just make your urethra bigger. Most men are OK with that. “Most?” Many, especially those who don’t get erectile dysfunction after surgery. “You’re the expert in urethral stricture disease?” Yep! Fellowship trained! So, are we looking at summer dates for surgery? “You’re just swatting mosquitos, aren’t you?” Pretty much. Sad!

Figure 1. Two mosquitos, only one of which can carry malaria. Which one? A classification system can help. (Hint, it’s B—Anopheles gambiae. Photo by James Gathany, Centers for Disease Control and Prevention.) A, Culiseta longiareolata. Photo by Joaquim Alves Gaspar.

Figure 2. Two short (1 cm) anterior urethral strictures. Different etiologies. Different treatments. A classification system can help. A, LSE classification L1S2aE3a. B, LSE classification L1S1aE2. Photo by Bradley A. Erickson.

Last year, the Trauma and Urologic Reconstructive Network of Surgeons (TURNS) published our initial attempt at an anterior urethral stricture (aUSD) taxonomy that classifies the disease process by length (L), stricture location (S) and etiology (E).³ The goal was to develop a common scientific language that could be used in a manner similar to that of the TNM classification system used for malignant tumors. Just like it would now seem ridiculous to describe a renal or bladder or prostate tumor (especially when developing the treatment plan) without describing its clinical classification, we hope that the LSE system will be used in a similar manner for aUSD. Only time will tell.

But there is still more to classify in benign reconstructive urology. Here are the tough questions our group asked itself repeatedly, and continuously, during the process of developing the LSE system that might expedite and organize future endeavors:

1. Does the condition need to be classified? To answer this question, one should simply ask themselves this: When reading a surgical outcomes paper, how confident are you that the condition the authors are talking about is the same condition that you manage in your own practice? I have frequently found myself dismissing new surgical techniques, or minimizing results that are counter to my own clinical experience, by simply saying, “We must be talking about different things.” Classification should decrease those concerns, improve confidence in published work and provide the framework for collaborative study by using the same language.
2. Can the disease process be classified? A requirement here is the ability to identify, and obtain, information on disease heterogeneity with high reproducibility. For the LSE system, we focused on variability in stricture location, length and the etiology of the stricture, all easily obtainable with a retrograde urethrogram and physical examination. But in other conditions, one might want to include a measure of functionality, such as severity and degree of incontinence, or bladder volumes and voiding pressures. When considering reproducibility, one must also strive toward tethering the classification to a test that is accessible to all (eg requiring functional magnetic resonance imaging [fMRI] might limit the system’s global reach).
3. Is the classification system reproducible? Once you’ve established how it is going to be classified, will clinicians and researchers across the globe classify a particular disease the same way? The key to making the system reproducible is making it easy to use: clear anatomical landmarks (when applicable), widely available imaging ± functional studies and limiting the use of subjective criteria. (When developing the LSE system, this is the stage of the process that took the longest—but was without a doubt the most important step.)
4. Does your new classification system matter clinically? Congratulations, you’ve created a classification system—but will it help your clinical practice? The first real-world test is to determine if all pathologies you’d like to classify can be classified (ie any “one-offs” where the system fails? If so, this will limit enthusiasm for use). Next, does the classification system help you decide what treatments should be offered (ie does disease heterogeneity change how the disease is managed)? Finally, if you were to provide just the disease classification to a colleague familiar with the system, without providing them the clinical information used to classify, would they understand that specific patient’s pathology? Here, any and all discrepancies must be assumed to be valid, and necessary modifications should be made.
5. Can you turn your classification system into a staging system? It is easy to forget that classification is different from staging; classification describes heterogeneity, while staging attaches classification to an outcome. Take the TNM system for kidney cancer: while a T1 tumor is (relatively) small and doesn’t involve the renal vein, any nodal involvement will bump the cancer to stage III, regardless of tumor size. (Notably, we expect to find a similar relationship in aUSD with lichen sclerosus.) But what is the outcome for benign disease? TNM staging systems tether themselves to the ultimate outcome—death, an objective, uncontroversial measure. Benign disease outcomes are more subjective—and though we often find ourselves trying to use objective measures, like repeat surgery, given the relative ease of obtainment, the meaning of these outcomes is fraught with problems. (I propose consensus statements as a starting point.)
6. Is your system malleable? History does not treat initial attempts at disease classification kindly. But those that have survived, like the TNM, have done so by allowing for change and for modifications, the most familiar example being the addition of the “S” (serum) markers to testicular cancer staging. Ultimately, as diagnostics become more precise, treatments more advanced and understanding of disease more comprehensive, the system must adapt or it will no longer serve its original clinical purpose.
7. Will your classification system move the field forward? There are 2 goals of classification with regard to field advancement: 1) Will the system help to power clinical trials? The key to a good clinical trial is that the cohort must be as homogeneous as possible so any outcome variability can be attributed to the intervention (eg urethroplasty type). This homogenization decreases the generalizability of the intervention, but, of course, that’s the whole point. 2) Will the system encourage collaboration and meta-analyses? A common language builds trust among institutions and discourages the age-old practice among surgeons of indirectly telling everyone how good they are at surgery through single-center studies.

There are now 20 formal Society of Genitourinary Reconstructive Surgeons (GURS) fellowships available to graduating urology residents and few academic programs left in the country without a urologist dedicated to urological reconstruction—many have 2 or more. The time is now that we all start figuring out how to use the same language to push the field beyond swatting mosquitos.