Why Nylon Sutures Have No Place Inside a CNVR Patient

In the tightly balanced world of Catch-Neuter-Vaccinate-Release (CNVR) programmes, every pound and every minute counts. Programme managers must carefully juggle animal welfare, efficiency, and long-term sustainability. From anaesthesia to analgesia, every decision matters.

Yet among these choices, one quietly shapes outcomes in ways that are often overlooked: the choice of suture material. It’s a frequently neglected part of the CNVR conversation, but one with far-reaching implications for healing, pain, infection risk, and post-operative welfare, especially when animals are released without follow-up.

Suture material might not grab headlines, but its impact runs deep.

Dogstar’s Position

At Dogstar Foundation, we take a clear and uncompromising stance: nylon sutures have no place inside a CNVR patient. That includes internal closures and, critically, vessel ligation. This isn’t just a clinical preference — it’s an ethical imperative, grounded in veterinary science, surgical outcomes, and the unchangeable realities of free-roaming animal welfare.

However, we also recognise nuance. While our position is that the internal use of nylon is unacceptable in elective surgery, particularly in unmonitored, free-roaming patients, we understand that access to absorbable sutures may be limited by funding constraints.

In these situations, nylon may be used for external closure only, and only under strict conditions. The dog must be retrievable for suture removal, such as in community-owned or temporarily sheltered animals. Even then, the surgical site must be low-tension, and the risk of trauma or interference must be minimal.

This is not an endorsement of nylon, but a recognition of imperfect environments. The goal must always be to phase out non-absorbable sutures entirely in CNVR surgeries and to advocate for better funding and procurement systems that make ethical choices possible, not optional.

Why Internal Nylon Has No Place in CNVR

1. Nylon requires removal. CNVR offers no second chances.

CNVR animals are not post-operative patients in a clinical setting. They are returned to their environment within hours, with no guarantee of follow-up. Internal nylon sutures or ligatures cannot be removed, cannot be monitored, and cannot be adjusted. If they cause a reaction or fail, the animal suffers — silently, invisibly, and often fatally.

2. Nylon is a foreign body that stays forever.

While considered inert, nylon is not biologically absorbed. Its long-term presence can trigger chronic inflammation, granulomas, or suture sinus formation. In the case of ligatures, retained nylon around blood vessels can become a nidus for infection, especially in field conditions where sterility may be compromised.

3. It signals elevated risk of infection and raises red flags about AMR and overall surgical standards.

Nylon itself does not directly cause antimicrobial resistance (AMR), but in low-resource CNVR settings, the Nylon used is often unsterile, and its use significantly increases the risk of infection. And in the absence of sterile technique, reliable instrument processing, or consistent pain management, it becomes part of a broader pattern of surgical compromise.

Programmes using nylon are often the ones least likely to have access to surgical autoclaves, sterile kits, gloves, or analgesia. In these cases, nylon becomes a red flag — not just a material risk, but a warning that wider surgical standards may be underfunded or overlooked. And where infection control fails, antibiotic misuse often follows, feeding into the global crisis of AMR.

Suture material is never just a technical decision; it reflects the entire surgical system behind it.

4. It violates the welfare principles of CNVR.

CNVR is not a numbers game. The goal is not just to sterilise as many animals as possible, but to do so ethically, humanely, and sustainably.

At Dogstar, we define “the highest possible standard of care” not as an unreachable ideal, but as a practical, field-appropriate benchmark. It means using trained personnel, sterile technique, multi-modal pain relief, and suture materials that support safe healing.

This standard aligns with international best practice, including:

• WOAH (OIE) Terrestrial Code, which requires that procedures reduce pain, distress, and infection risk.
• ICAM’s Humane Dog Population Management Guidance, which defines success in terms of individual patient welfare, not just volume.

Using internal nylon, knowing it cannot be removed or monitored, is not a cost-saving measure. It is a welfare compromise, and one we must never accept.

The Conditional Use of Nylon for External Closure

In resource-limited settings where absorbable sutures are in short supply, external nylon may be used — but only under strict conditions:

• The nylon must be sterile at the time of use.
• The surgical site must be low-tension and unlikely to be irritated by normal animal behaviour.
• The animal must be released into an environment where follow-up is possible, such as with a caregiver or at a shelter.
• Suture technique must minimise exposure and be securely tied to prevent premature removal.

Even in these cases, absorbable sutures are vastly preferable. They eliminate the need for removal, reduce post-op complications, and align with the long-term welfare goals of humane CNVR.

A Call to Elevate Standards — Not Just Scale

The CNVR sector is often forced to make difficult choices. But compromising on internal suture quality must never be one of them. We must advocate for procurement systems, funding models, and supply chains that treat absorbable sutures as standard, not a luxury.

The animals we treat deserve more than the minimum. They deserve procedures that are not only fast and affordable but also compassionate, safe, and grounded in best-practice veterinary science.

Nylon may have been an accepted standard once, but today, we know better and we must do better. Internal use has no place in ethical CNVR.