Tortoises are common pets in the United Kingdom, often handed down through generations due to their very long lifespans. Many tortoises are kept in the garden over the warm summer months and are very good at climbing and escaping. As a result of misadventure, tortoises can find themselves in dangerous situations involving other animals, heavy objects and, sometimes, even cars. It is, therefore, not uncommon for tortoises to present with shell fractures, puncture wounds or other severe injuries as a result of misadventure.
When presented with a tortoise that has a shell fracture, analgesia is paramount as shell fractures are also bone fractures and should be treated as such. While there is limited but growing information about analgesia in reptile species, a pure mu opioid is recommended in these cases for analgesia.
Shell anatomy
The tortoise shell is made up of two main components: the plastron (the ventral shell) and the carapace (the dorsal shell). The shell is covered with “scutes” – hard epidermal layers that cover the bone just under the surface (McArthur, 2004). The carapace and plastron are connected laterally by the “bridge”. Some chelonians have hinge joints in their plastron, which aid in protection from predators or reproduction.
The ribs are integrated into the carapace, but chelonians lack a sternum (Kirchgessner and Mitchell, 2009). The thoracic and lumbar vertebrae are fused and are attached to the neural bones of the carapace; however, the cervical and caudal vertebrae remain separate to allow for movement, including retraction of the head into the shell (Kirchgessner and Mitchell, 2009).
Common injuries
During warmer summer months, tortoises travel further distances in search of food or a mate, or sometimes they simply wander off. These misadventures can result in some of the most commonly seen tortoise injuries in clinical practice.
Dog or predator bites are a common presentation, especially when tortoises are left unsupervised. While terrestrial pet tortoise species can retract their heads, legs and tails into their shell to protect the softer structures, dogs and foxes can chew at the external shell and cause significant damage. Many patients present with absent marginal scutes and damage to the associated underlying bone as the edges are chewed away, similar to a dog chewing a toy.
If the predator is large, depression fractures (Figure 1), penetration injuries into the coelomic cavity and fractures of the carapace and/or plastron (Figure 2) can occur if the bite force is large enough. A similar presentation can be seen in tortoises that are inappropriately hibernated outside and are predated on by rats, although usually the soft tissues in the legs are targeted first in these cases.
Crush injuries are also a common presentation of tortoise trauma, usually presenting as fracture or penetration of the carapace (Figure 3), sometimes with plastron involvement. This can be due to falling objects or, in severe cases, being run over by a motor vehicle, etc. The weight inflicted often determines the extent of the shell fractures. Lawn mower and strimmer injuries are less commonly seen but can occur if a tortoise is hidden in long grass. In particular, lawn mower injuries often result in avulsion of the scutes, fracture of the carapace or, in severe cases, avulsion of the dorsal carapace and spine.
While terrestrial pet tortoise species can retract their heads, legs and tails into their shell to protect the softer structures, dogs and foxes can chew at the external shell and cause significant damage
Initial triage
Following the administration of analgesia and the provision of warmth, a triage examination should be performed to assess the extent of the injuries. Some injuries are only superficial, with cracks to the scutes alone (Figure 4). Other injuries involve a full fracture or avulsion of the shell, and some injuries can be catastrophic, with severe exposure of the internal organs. It is important to have an assessment system in place to help guide treatment and advise owners on likely outcomes and treatment options.
Norton et al. (2019) suggest the following prognoses:
- Cases likely to have an excellent prognosis are those with recent (less than six hours), non-contaminated, singular and non-displaced fractures that do not involve the spine
- Cases that carry a good prognosis include tortoises with multiple unstable fractures, open fractures or only shallow puncture wounds less than 24 hours old
- A fair prognosis is given to tortoises with puncture wounds that penetrate the coelomic cavity or those with multiple fractures involving the pectoral or pelvic girdles. The exception is if an affected limb is unable to move at all or if the injuries are 24 hours old, which places the patient into a category of guarded prognosis
- Other cases with a guarded prognosis include those with punctured or contaminated visceral organs (Figure 5), those with severe contamination or myiasis, and reproductively active females with internally fractured eggs
- Cases carrying a grave prognosis include those with multiple fractures, spinal injuries and concurrent internal injuries, and those missing large aspects of the carapace or plastron
Treatment
Once the injuries have been assessed and analgesia has been administered, several initial steps for treatment greatly help to improve long-term prognosis.
All fractures and wounds resulting in bone exposure should be irrigated and cleaned of any debris using warmed sterile saline, lactated Ringer’s, dilute (0.05 percent) chlorhexidine or dilute iodine (0.1 to 1 percent) (Norton et al., 2019). It is important to take care when irrigating wounds that penetrate the coelomic cavity around the area of the lungs, as inadvertent aspiration may occur through these wounds. Patients should be positioned so irrigating fluid runs away from wounds, not towards penetration injuries.
It is important to take care when irrigating wounds that penetrate the coelomic cavity around the area of the lungs, as inadvertent aspiration may occur
Open wounds and fractures should always be treated as contaminated, and appropriate antibiotic therapy should be instigated (Chitty and Raftery, 2013), ideally after a swab has been taken for bacterial and fungal culture. Warmed fluids should also be provided to the patient, as they are likely in shock.
Diagnostic imaging
Bite wounds can push shell fragments and bone into underlying soft tissues, which can be identified with diagnostic imaging (Chitty and Raftery, 2013). So, once the patient is stable, radiographs or computed tomography (CT) (Figure 6) can help assess fractures and identify those not apparent on physical examination (Abou-Madi et al., 2004). CT is excellent for assessing damage to internal viscera, especially in cases where coelomic penetration has occurred. Craniocaudal and lateral radiographic views can also help to assess lung fields following trauma to the carapace (Norton et al., 2019).
Dressings and stabilisation
Treatment of the injury depends on many factors. Injuries that have resulted in avulsion of the shell edges, such as dog bite wounds, should be dressed in wet-to-dry dressings (Figures 7A and 7B). These dressings should be changed daily for 10 to 14 days to debride necrotic debris and give the tissue time to declare itself. Once healthy tissue can be differentiated from necrotic tissue, wounds can be surgically debrided under anaesthesia and covered with a cool-set dental acrylic such as Kooliner (Miles, 2022). Exothermic products should not be used, as they can cause thermal injury to the tissue.
Wounds should never be permanently closed or covered until the clinician can be certain that there is no infection and that all the necrotic tissue can be debrided. Minor wounds can be treated with topical silver solutions, which are useful for their antimicrobial activity (Norton et al., 2019). Appropriate analgesia should be provided at all stages of healing.
Wounds should never be permanently closed or covered until the clinician can be certain that there is no infection and that all the necrotic tissue can be debrided
Shell fractures can be stabilised using several methods, including plates and screws, eye hooks, zip ties, and screw and wire combinations (Norton et al., 2019; Chitty and Raftery, 2013). If the coelomic membrane has been damaged or penetrated, the wound should be sutured and covered with a dressing to promote healing, ensuring no infection is being closed in the coelomic cavity (Chitty and Raftery, 2013). Fibreglass has historically been used for shell fracture repairs; however, it is no longer recommended for traumatic shell injuries – external hardware is now the preferred method of fixation (Norton et al., 2019).
Treatment time and post-treatment care
Healing time for shell injuries depends on the severity of the fracture/injury, the degree of wound contamination and the metabolic status of the animal. Typically, healing time is 12 to 18 weeks in non-complicated cases (Hernandez-Divers, 2004); however, bone fracture repair can take up to six months or more (Norton et al., 2019). It is essential that owners understand that treatment of shell injuries can be a long process and may require multiple procedures.
It is essential that owners understand that treatment of shell injuries can be a long process and may require multiple procedures
Owners can be taught how to change bandages and flush wounds safely at home, and most owners are more than willing to provide this nursing care to their pets.
Summary
Tortoises presenting with shell trauma often have severe injuries; however, prognosis is often good, and patients should not be euthanised because of these injuries. Clinicians should follow a prognosis guideline to help determine if treatment would be viable. In all cases, clients should be made aware of the timeline for treatment to avoid unrealistic expectations.