Presenting problem: Shell Fractures in Chelonians

Understanding shell fractures

Shell fractures are one of the more common presentations of Chelonia to the private exotic animal practitioner. Shell fractures are frequently caused by vehicular trauma, lawn mowers, predation by dogs and raccoons, or drops from balconies or porches. I have even seen one case in which a person tried to use a tortoise as a “step stool”.

Often seen as a “chronic” issue, having occurred days before they present, shell fractures need to be treated as an emergency situation and dealt with both as a localized and as a systemic problem.

 Carapacial fracture in a box turtle

Figure 1. Carapacial fracture in a box turtle (Terrapene carolina spp.) Image provided by Mike Comella of Wichita Falls Reptile Rescue.

The skin is the barrier between the dirty “outside” and the sterile “inside” in most animals, and the shell serves a similar role as it covers much of the chelonian body. Shell trauma breaches this level of protection and compromises the overall health of the animal. In these cases, the dermal layer is damaged, but associated tissues are also potentially injured, including the ribs, pelvic and thoracic girdle, spinal column, supporting musculature, and viscera. Thus, shell fractures in Chelonia need to be thought less of as a superficial wound and more of as a deep penetrating wound with implied risks to the entire animal.

 

Key points of urgent care

Exposure and wound contamination are the greatest concerns. Shell fractures are frequently associated with infectious material entering the wounds, extensive soft tissue damage and visceral exposure. As would be expected, there is a great propensity for shock-related issues and pain in these injuries.

It is not uncommon to have the chelonian patient present with fractures that are several days old. With these cases, not only the presenting wound needs to be addressed, but also issues associated with chronic tissue exposure, including infection, necrosis and devitalization, and systemic diseases.

It is important to advise owners of the inherent risks present in these patients. Both immediate and long-term treatments are necessary. Depending on the specific condition, the owner should be informed of potential complications including possible failure to heal. Due to the inherently slow healing rates of Chelonia, a thorough understanding that treatment will take at least several months for a full recovery, and that the shell may actually take years to return to a “normal” appearance needs to be conveyed.

 

Case management

Review the history and husbandry

In all cases, a thorough assessment of the patient’s history is essential, as well as a review of the long-term husbandry provided. The clinician needs to be familiar with the natural history and captive care of the species treated. This is essential for a good recovery because if the physiological needs of the patient are not met, it is unlikely the animal will reach a sufficient health plane to recover.
Inspect the wounds

  • Thoroughly evaluate and examine all traumatized areas to determine the depth of the wounds and attempt to ascertain what other structures are damaged (Fig 2-4). Perform a complete physical examination is needed to determine if there is internal hemorrhage, visceral damage or neurological injury. Use pressure and/or flexion while examining the carapace and plastron to check for fracture lines hidden beneath or between scutes.
     A Russian tortoise upon presentation of multiple fractures

    Figure 2. A Russian tortoise (Testudo horsfieldii) upon presentation of multiple fractures. Image by Dr. Adolf Maas. Click image to enlarge.

    Carapacial fracture exposing an egg (1) and the spine

    Figure 3. Carapacial fracture exposing an egg (1) and the spine (2). Image provided by Mike Comella. Click image to enlarge.

    Fracture involving the carapace and punctured peritoneum

    Figure 4. Fracture involving the carapace and punctured peritoneum. (thin yellow line). Image provided by Mike Comella. Click image to enlarge.

  • Small amounts of sterile saline applied to fractures can help determine if there is air movement in cases of pulmonary involvement.
  • Visually assess wounds using magnification and direct light sources for contamination by foreign material, bone fragments, and shell material that might create a nidus of infection or sequestrum.

Diagnostic testing

  • As with any serious trauma, bacterial and/or fungal culture and sensitivity testing is necessary to provide appropriate antimicrobial therapy.
  • Orthogonal and oblique radiographs can help determine depth and extent of fractures, alignment of fractures after stabilization, and progress of bone healing.
  • Initial and follow-up complete blood counts should be used to establish baseline values and to follow trends while monitoring for occult infections and recovery.
  • Plasma chemistries can assess for conditions unrelated to the fractures and to establish if treatment is necessary for chronic or husbandry-related conditions.

Patient stabilization

As with any traumatic injury to a patient, Chelonia can undergo shock and suffer from fluid loss. Fluid therapy can be easily performed either with placement of an intravenous (IV) catheter (jugular is preferred, but usually required sedation) or an intraosseous (IO) catheter. My personal preference is to place the IO catheter in either the margin of the carapace or the bridge between the carapace and plastron. These can be easily accomplished with only local anesthesia (e.g. lidocaine 2 mg/kg in the subkeratineous tissue and periosteum), or with heavy sedation or light anesthesia. Consider species’ natural history and serum chemistry/calculated osmolality to determine fluid type as well as fluid rate.

Pain is a significant, but often undervalued, concern in reptile patients. Chelonia are typically stoic and will continue to try to escape even with the worst of fractures. Pain control is essential both for patient care as well as for therapy, and analgesics need to be administered prior to onset of wound care and other therapies. NSAIDs are commonly used in treatment of Chelonia and are believed to be effective, and there are many published reports and studies of opiate use in a number of species. Again, the species and natural history must be considered when choosing analgesic agents, as well as the biochemical profile and general condition of the patient.

Red-eared slider with severe infection

Figure 5. This red-eared slider (Trachemys scripta elegans) showed no obvious signs of pain or discomfort despite severe infection and serious involvement of internal organs from this chronic wound. Image provided by Mike Comella. Click image to enlarge.

Soft tissue treatment

Since most shell fractures also have associated soft tissue damage, this trauma must be addressed at presentation, often before fracture treatment is initiated.

  • Clear all wounds of debris, and debride devitalized and/or necrotic tissue.
  • Flush and irrigate the wounds with sterile saline when there is no direct pulmonary involvement. A small amount of iodine solution can be added to the saline and used as a very effective antiseptic.

    Although vacuum-assisted closure techniques have been advised for many severe or badly contaminated fractures, and whereas they can work exceptionally well, this technique has also been found to generate unique complications in Chelonia (Box 1).

    Box 1. Clinical tip
    Chlorhexidine solution is not advised for use with chelonians because there have been reports of toxicity and possibly fatalities associated with its use in irrigating wounds (Lloyd 1996).
  • Bandaging both with adherent dressings and replaceable cap technique (Maas, Forthcoming 2014) can be used in many cases to protect and debride the wound until adequate granulation beds and neoepithelialization are established.

    Bandaged shell fracture

    Figure 6. Bandaged shell fracture. Image provided by Mike Comella.

  • In many cases where the shell injury involves the epidermal junction, consider whether or not these wounds can be sutured (Box 2).
    Box 2. The wound can be surgically closed if...

    • The wound is minimally contaminated (or can be well debrided).

    • The wound is reasonably fresh.

    • There is sufficient tissue to provide closure without placing the tissues under tension, this can be performed the same as for any animal.

    Skin that is avulsed from the shell margin can be directly sutured back to the margin, taking bites with the needle directly into the periosteum/subkeratineous connective tissue. (Editor’s note: Subkeratineous refers to the tissue deep to the keratin scutes of the shell).

     

    Stabilization of fractures

    The last stage of treatment is realignment and stabilization of shell fractures. As stated previously, the shell is not only a “superficial” layer of bone, but also incorporates the ribs, the spinal column and is fused to both the pelvic and thoracic girdles. Fractures virtually always involve one of these other bone structures and when realigning the fragments it becomes even more important to consider anatomic positioning and underlying structures for the best possible recovery.

    As with any fracture, the best way to achieve rapid repair is to maintain both close alignment between fragments (preferably with the fracture line under compression) and high stability with no motion at the fracture line.

    Traditionally in many mammalian long bone fractures, a cast was used externally to align bone fragments, stabilize the fracture site, and promote healing. In Chelonia, fiberglass, acrylic, and/or epoxy have been used as a “cast” to fuse fragments and allow healing. However sealing the wounds often traps infectious agents causing profound cutaneous or keratinaceous infections and deep osteomyelitis with a high risk of sequestrum formation. The growth of pathogens puts the patient at risk for delayed healing at best, and at worst, septicemia and death.

    Current therapies performed by experienced reptile veterinarians to stabilize fractures involve screws and tension wires, plate application, “braces”, and even “zip-ties” (Fig 7-Fig 10). Any of these techniques can work quite well and promote healing of linear fractures when installed correctly and maintained properly over the course of healing.

    Surgical alignment of shell fracture fragments

    Figure 7. Surgical alignment of shell fracture fragments Image provided by Dr. Adolf Maas. Click image to enlarge.

    Pre-operative appearance of compound carapace fractures and fracture wired

    Figure 8. Pre-operative appearance of compound carapace fractures (A). Carapacial fracture wired (B). Images by Dr. Shane Simpson. Click images to enlarge.

    Depression fractures are particularly challenging to both stabilize and align (Fig 9). Recent developments in anchoring and application of tension have allowed these lesions to heal and recover as well as any other fracture.

    Depression fractures are particularly difficult to stabilize and align

    Figure 9. Depression fractures are particularly difficult to stabilize and align. Left, image provided by Dr. Shane Simpson. Right, image provided by Mike Comella. Click images to enlarge.

    Long-term management

    Soft tissue injures and exposed tissues (secondary to shell loss) heal relatively quickly, and sutures can be removed after 2-3 weeks. Areas that require granulation and healing by second intention can easily take 2-3 months to heal.

    Land tortoises should have daily cleaning and bandaging as part of their nursing care, and topical treatments with either water- or petroleum-based products can be beneficial depending on the specific case. Water-based wound-care products, such as hydrolyzed collagen gels, can improve healing and prevent infection and may be indicated in select cases.

    Aquatic turtles are more challenging to provide nursing care. As these species as a whole are more prone to dehydration, “dry-docking”, if not carefully managed, can have serious implications. Commonly, these patients will be soaked in clean water one to four times daily (depending on species) for rehydration, followed by soaking in an iodine solution for wound disinfection followed by gentle debridement and rebandaging.

    Followed the warm water soak with dilute iodine solution for wound antisepsis followed by gentle debridement and rebandaging.

    The phrase, “As slow as a turtle’s pace” has new meaning in the recovery of shell trauma. Whereas many soft tissue injuries heal at a relatively rapid pace, shell fractures in Chelonia can easily require 4-18 months to become stable. If there is bone loss, the lesion will heal well once the wounds are stable and free of debris, infection, and devitalized tissue. With time, new bone forms and fills in the defect(s). Concurrently, new keratin will also form in and around the traumatized areas and the external shell will again become complete.

    Tortise with healed fractures

    Figure 10. Same tortoise as in Figure 2, after fractures have healed and fixator removed. Image by Dr. Adolf Maas. Click image to enlarge

    References