​Primary closure versus delayed or no closure for traumatic wounds due to mammalian bite

Plain Language Summary of Cochrane Systematic Review by Bhaumik S et al. Link to paper.

Primary closure (immediate stitches) versus delayed closure (delayed stitches) or no closure (no stitches) for traumatic wounds due to mammalian bite

What is the aim of this review?

The aim of this review was to find out whether animal bite wounds heal better when they are closed with stitches straight away (primary closure), or if the wounds are left open to heal for a short time before closure (delayed closure) or not stitched at all (no closure). We wanted to find out which wounds healed fastest, and if the method of closure affected the likelihood of wound infection, the appearance of the scar, the length of time patients were in hospital, and more serious side effects such as death. To answer this question, we collected and analysed all relevant studies (randomised controlled trials). Randomised controlled trials are medical studies where people are chosen at random to receive different treatments. This type of trial provides the most reliable health evidence. We found four relevant studies.

Key messages

All the studies we found concerned dog bites. In terms of wound infection, we cannot be certain whether it is better to close dog bite wounds straight away, or wait a while before stitching, or leave them with no stitches. There was little difference in the appearance of the bite scar. Most of the evidence we found was of low certainty due to the size of the studies and the methods used.

What was studied in the review?

Mammalian bite wounds from animals such as dogs, cats and monkeys are a common problem throughout the world. In developed countries, many bite wounds are caused by domestic pets. In lower‐income countries bites can also be caused by wild animals. Dogs are generally responsible for the majority of bites. Bite wounds are at high risk of infection as microbes are transmitted into the wound from the animal’s mouth. In lower‐income countries these wound infections can lead to serious complications and in some cases death.

The first priorities when treating an animal bite are to stop the flow of blood from the wound, provide pain relief, and prevent infection. This can include appropriate vaccination against tetanus and rabies. It is often recommended that bite wounds are not stitched straight away if infection is suspected, as closing an infected wound could delay healing and be potentially fatal.

What are the main results of the review?

In July 2019 we searched for randomised controlled trials comparing primary closure versus delayed or no closure for mammalian bite wounds. We found four relevant studies on dog bites. They were carried out in the UK, Greece and China. No other mammalian bite studies were identified. Three of the studies we included compared primary closure with sutures (immediate stitches) with no closure for dog bite wounds. One study compared primary closure with delayed closure for dog bites. The people in the studies were followed, where stated, from 14 days to three months. Overall, participants from both sexes and all age groups were represented.

We are uncertain whether primary closure of dog bite wounds increases the proportion of wounds which are infection‐free compared with no closure (very low‐certainty evidence from two studies including a total of 782 people) and compared with delayed closure (very low‐certainty evidence from one study with a total of 120 people). There is little difference in the appearance of dog bite wounds when primary closure is compared with no closure (moderate‐certainty evidence from one study with a total of 182 participants). None of the included studies reported proportion of wounds healed, the time to complete wound healing, length of hospital stay or adverse events. The number of people in the included studies was small, and the people who assessed the outcomes were aware of which treatment had been given. Both of these are reasons why the results are uncertain.

How up to date is this review?

We searched for studies that had been published up to July 2019.

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