Extraction of Nonvital Tusks in a Standing Sedated Bornean Elephant Using a Simple Noncollapsing Rotational Extraction Technique: A Case Report

Introduction

Elephant tusk injuries can occur in intraspecific, accidental collisions with objects or vehicles, and by human-related injuries. In particular, elephants with broken or injured tusks are commonly reported in areas with higher human–elephant conflicts, such as areas near human settlements, agricultural fields, or areas where elephants are kept in captivity.^1–3 In such areas, encounters with fencing wires or steel bars designed for animal enclosures, human protection, and crop safeguarding can cause significant tusk trauma.

In a recent report successful vital pulp therapy in a juvenile elephant tusk at 30-h postinjury was achieved after 3 years of follow up. ³ Similar to other species, vital pulp therapy within 48 h of an acute complicated crown fracture remains the gold standard for tooth preservation.^1,2,4 However, achieving this timeframe for wild or semiwild animals requires close observation by an experienced caregiver, consequently limiting treatment options to extraction of the infected tusks.

Tusk extraction typically involves anesthesia to minimize pain and distress for the elephant during the procedure. Thereafter, the tusk is resected and sectioned for piecemeal removal using specialized equipment. It is noteworthy that extraction of an infected tusk can have serious complications, including increased infection risk, feeding difficulty, and reduced social status within the herd. Therefore, this procedure is considered as a last resort when all other options have been exhausted, and the elephant's health is at risk.^4–7

To the best of the authors’ knowledge, no studies have been published regarding tusk trauma management in Bornean elephants using the simple extraction technique with standing sedation and locoregional anesthesia.

Case Presentation

An 8-year-old male Bornean elephant (Elephas maximus borneensis) weighing approximately 900 kg showed bilateral transverse fractures of the tusks at their alveolar margins. Born in the wild, he was rescued as a calf and brought into captivity after being abandoned by his herd. In 2016, he was diagnosed with asymptomatic elephant endotheliotropic herpes virus-associated viremia. ⁸ The tusk pathology was attributed to repetitive trauma against the horizontal steel bars in the enclosure, leading to abrasion and complete fracture of tusks bilaterally.

Tusk fracture and consequent pulpitis were first identified and diagnosed in December 2020. Under sedation, the elephant underwent investigation, pulp debridement, radiography, and pulposcopy. Both fractures extended into the pulp cavity and were classified as Ellis Class III fracture ⁴ (Figure 1).

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Figure 1.

Photograph of the elephant showing class III fractures of the left and right tusks.

The pulp cavities were extensively flushed with clean water, diluted chlorhexidine, and iodine to remove debris (feces, soil, and food material), necrotic tissue, and purulent blood-tinged exudate.

A preoperative blood count revealed anemia and thrombocytopenia, with no significant changes in leukocytes. Serum chemistry indicated slight elevation in alanine aminotransferase and aspartate aminotransferase levels. Preoperatively tramadol^a (0.1 mg/kg) was administered intravenously (IV) for pain control and ranitidine HCl^b (0.5 mg/kg) IV to reduce gastric secretions. Ivermectin^c (0.01 mg/kg) was administered intramuscularly (IM) to prevent ectoparasitic infestation of wounds. Normal saline solution^d and dextrose 5% solution^e (6 L/h) and a vitamin supplement^f (100 mL) was given IV intraoperatively.

A portable X-ray generator^g and phosphor plates^h using 85 kVp and 10 mAs was used to obtain intraoral craniocaudal radiographs. Radiographic assessment revealed a diameter of 53.8 and 60.2 mm at the widest points and 45.5 and 54.3 mm at the level of the tusk sheath for the right and left tusks, respectively. The length of the tusk measured from the estimated level of the tusk sheath to the last visible area of the tusks was 97.5 and 144.4 mm for the right and left tusks, respectively (Figures 2A and B). The right tusk displayed a lateral crown fracture extending into the sulcus, a large ivory pulp stone (endolith) was found within the fractured left tusk. The examination confirmed that both tusks were nonvital, with no healthy pulp present. Bacterial culture of the purulent exudates revealed heavy growth of Pseudomonas aeruginosa, Morganella morganii, and Klebsiella species.

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Figure 2.

Intraoral radiographs using a craniocaudal view obtained at a 30° angle showing (A) a lateral transverse crown fracture extending into the sulcus of the right tusk and (B) an elongated ivory pearl within the lateral transverse fractured left tusk.

Following diagnosis, daily flushing of the pulp cavities with diluted chlorhexidine and iodine was continued, along with systemic antibiotic therapy with gentamicinⁱ (4.4 mg/kg) SID for 10 days and ceftiofur^j (6.6 mg/kg) SID for 5 days. However, upon treatment discontinuation, purulent discharge reappeared in both exposed tusks. This persisted for 2 years, resulting in the loss of growth and mobility in both tusks.

In September 2022, extraction of both tusks was planned and the Sabah Wildlife Department granted consent for the surgical extraction of the tusks under standing sedation.

The elephant was fasted for 8 h preoperatively. Physical restraint was achieved using ropes and chains secured to the barrier fence, and a chest and abdominal belt was employed to prevent recumbency. ⁹ Initial sedation was achieved with dexmedetomidine HCl^k (1.0 mg, approximately 1.11 µg/kg) by IM injection. ¹⁰ Onset of sedative signs (scant ear movement, slight penile prolapse, and mild pupillary dilation) occurred within 12 min, with full standing sedation by 18 min postadministration (stillness, trunk immobility, complete pupillary dilation, and complete penile protrusion). Subsequently, an infraorbital nerve block and perialveolar infiltration with 20 mL of 2% lidocaine HCl were performed. The infraorbital foramen was located, with the assistance of a skull (Figure 3A), by palpation of the infraorbital nerve 5 cm dorsal to the imaginary line between the medial canthus and lateral wall of the tusk at two-thirds the distance from the lateral wall of the tusk sheath (Figure 3B). Intraligamentary infiltration was performed dorsally, laterally, and ventrally in the periodontal ligament space. Throughout the procedure, vital signs were monitored and recorded, pulse rate 47 to 89 bpm, respiratory rate 3 to 8 bpm, capillary refill time <2 s, body temperature 34.0 to 35.0°C, oxygen saturation 88 to 100%, and end tidal CO₂ of 33 to 51 mm Hg measured by placing a capnometer inside the nostril. In addition, hypersalivation, urine dripping, and pink mucous membranes were observed during the procedure.

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Figure 3.

(A) Dry skull of the elephant used to assist in locating the infraorbital foramen (directly below the asterisk). (B) Clinical administration of the infraorbital nerve block performed on the elephant.

The left tusk was extracted first. The periodontal ligament was severed by first inserting a 20 cm custom made elephant elevator (Figure 4A) between the tusk and alveolar bone to a depth of half its length using a surgical mallet to ensure that elevator could be withdrawn without excessive force. Insertion and withdrawal were repeated around the circumference of the tusk. Thereafter, the second 30 cm custom made elephant elevator was inserted to a depth of the premeasured tusk length around the circumference of the tusk. Following circumferential loosening, the tusk became slightly mobile and rotatable. Equine 4-prong dental forceps were applied to expose the tusk crown, and the inner tube of a bicycle tire was wrapped around the forceps handle for improved grip (Figure 4B). The forceps were rotated along the long axis of the tusk to continuously severe the periodontal ligament. Once the tusk was loose, with foamy blood indicating continued ligament disruption, the tusk was forced downward using a mallet on the forceps. This resulted in complete removal of the left tusk and dislodgment of the ivory pearl. The left tusk extraction was completed within 90 min (Figure 4C).

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Figure 4.

(A) A custom made elephant elevator is inserted in the periodontal ligament space to disrupt the periodontal ligament of the tusk. (B) A bicycle tire inner tube is wrapped around the handles of an equine 4-prong dental forceps to increase the grip. (C) Photograph showing the completely removed right tusk (left), the custom made blade of elevator (middle) and left tusk (right).

At 104 min after initial dexmedetomidine HCl injection, the elephant exhibited signs of mild awakening (body rocking, ear flapping, and occasional trunk movement). A second injection of dexmedetomidine HCl (0.25 mg, approximately 0.28 µg/kg) was administered IM 108 min after the initial dose, resulting in trunk relaxation within 10 min, although the elephant still responded to extraction pain. A third injection of dexmedetomidine HCl (0.25 mg) was administered at 153 min. The right tusk was extracted using the same method, which resulted in its complete extraction (Figure 4C) at 196 min. The extraction sites were curetted using a long equine dental curette, followed by rinsing with 0.1% chlorhexidine using a garden pressure pump. Postoperative radiographs were performed to confirm complete tusk removal (Figures 5A and B). The extraction sites were packed with sausage-shaped Gamgee bandage impregnated with terramycin. Atipamezole HCl^l (7.5 mg) was then administered IM to reverse anesthesia. Recovery signs (trunk movement, ear flapping, tail swinging, and body movement) were observed within 5 min, and full recovery was achieved 10 min after atipamezole administration. The elephant exhibited a good postoperative recovery, characterized by normal drinking and eating behaviors (Figure 6).

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Figure 5.

Postoperative craniocaudal oblique radiographs showed complete removal of both the (A) right and (B) left tusks.

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Figure 6.

Postoperative photographs on day 1 showing sockets filled with sausage-shaped gamgee bandages.

Postoperatively, ceftiofur sodium^m (10 mg/kg) was administered IM SID for 5 days. Further analgesia was provided with butorphanolⁿ (0.015 mg/kg) IM SID on the second postoperative day (Day 2) and tramadol (0.1 mg/kg) IM SID for the following 3 days (Days 3-5). Additionally, ferrous supplement^o (2 gm) was administered daily for 10 days.

Topical wound care included daily pulsating spray washes with 0.1% chlorhexidine solution to remove debris, purulent discharge, and blood clots. The Gamgee bandages were replaced daily for 3 days to prevent lodging of food and other debris. Reduction in the tusk socket diameter was observed on Day 4. Since the Gamgee bandages could no longer be inserted into the socket, only wound cleaning and topical dressing were performed thereafter.

Granulation tissue gradually filled the wounds, leading to minimal purulent discharge and debris on Day 14 (Figure 7A and B) and Day 30 postoperatively. Although granulation tissue growth progressed faster in the right tusk socket, more purulent discharge was also observed on this side.

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Figure 7.

Postoperative photographs on day 14 showing the (A) right and (B) left tusk extraction sites healing.

Discussion

Tusk removal in elephants is a procedure based on the stage of vitality and remaining healthy pulp of the tusk. Treatment options for fractured tusks may involve conservative medical approaches, pulpotomy or pulpectomy with reconstruction, or surgical extraction depending on the vitality of the tusk, duration from time of injury to treatment, and medical experience of the operator and availability of equipment.^3–7,10,11 In the present case, topical and systemic antibiotics proved ineffective in the conservative management of the fractured tusks. Persistent purulent discharge and absent tusk growth for 2 years were indicative of nonvital septic tusks, making tusk extraction the recommended option for this case.

Although various tusk removal techniques have been previously described, including elastic band, ⁵ internal-collapsing,^4,7 and noncollapsing rotation, ⁶ literature on these techniques is limited. The elastic band technique can be performed without sedation with the assistance of a skilled elephant handler. ⁵ It involves placing an elastic band on the tusk and exerting force between the tusk and alveolar bone, which applies a continuous tension on the tusk. However, this treatment is not ethical, as it may cause prolonged discomfort for the elephant and should not be considered the treatment of choice. The internal collapse technique involves enlarging the pulp cavity using a large-diameter drill bit and partial sectioning of the rostral tusk using an electric saw. Following this, a custom-made elevator with a chisel blade is used to elevate and longitudinally section the tusk, which is then extracted via piecemeal removal. This technique carries high complication rates due to remnant tusk fragments and longitudinal fractures of the tusk. To avoid these complications, the noncollapsing rotational technique may be utilized.

Considering the high complication rates of the reported techniques and welfare concerns associated with the elastic band method, the authors designed a surgical extraction technique similar to those performed in human and veterinary dentistry.^12,13 This technique relies on periodontal ligament disruption by inserting a custom-made elevator between the tusk and alveolar bone. While this ensures a lower risk of uncontrollable longitudinal fractures of the tusk during sectioning, it is only advantageous for cylindrical tusks, seen in Asian elephants, and not for conical tusks, which are common in African elephants. In the present case, this technique was implemented successfully with minimal trauma. Furthermore, the custom-designed elevator represents an innovation in elephant veterinary medicine.

This case report shows that radiographic images can be used to evaluate the tusk shape. These images demonstrated that tusk shape in this Asian elephant was more cylindrical and had a shorter root compared to the conical shape and longer root extending to the base of the eye seen in African elephants, ⁷ thus allowing for easier nonsectioning extraction. However, the main limitation was that only a single radiographic plane was obtained instead of orthogonal views of the tusk due to the anatomy of the elephant's head that limited placement of the image cassette. In addition, the radiographic image also showed the presence of an ivory pearl in the left tusk. The ivory pearl results from mineralization of the connective tissue in the tusk. ¹⁴ In the present case, the ivory pearl had a large irregular shape, which may have resulted from long-term pulp inflammation and uncontrolled production of tusk dentine. The irregular shape of the ivory pearl may have played a role in the incomplete resolution as it may have led to retained infection and inflamed pulp. Despite the successful extraction performed in this case, other treatment options, including use of general anesthesia, the internal-collapsing technique, or multiple visits were considered were discussed prior to treatment.

Analgesia and pain management following tooth extraction is imperative due to the invasive nature of the procedure, which causes tissue trauma and inflammation. Furthermore, analgesia and pain management enhance patient comfort, minimizing the risk of complications associated with untreated pain, thereby promoting recovery outcomes. Butorphanol, an opioid analgesic, was selected for pain management in this case due to its potent analgesic properties suitable for moderate-to-severe pain. Subsequent to the surgical procedure, the elephant exhibited no signs of discomfort. Therefore, the analgesic regimen was revised and changed to tramadol, chosen for its efficacy in managing moderate pain and its availability in the field. Despite reported variability in efficacy scores when administering tramadol in elephants, ¹⁵ this drug is routinely employed with satisfactory outcomes in pain management practices for elephants in Malaysia and Thailand.

The daily wound dressing also played a pivotal role in achieving a successful outcome in this case. Proper cleaning with a seton, together with antibiotic administration, not only prevents secondary infection but also promotes healing. This highlights the importance of regular wound care in ensuring optimal recovery. Standing sedation with dexmedetomidine HCl and locoregional anesthesia facilitated an uneventful surgical extraction. Sedation signs observed in the present case align with those in previous reported studies^16,17 indicating safe surgical manipulation of the elephant. Notably, while a previous study employed a 10-fold atipamezole dosage to antagonize dexmedetomidine, ¹⁸ only a 5-fold dose was used in this case. This discrepancy may be attributed to the procedure duration of more than 3 h. Nevertheless, the elephant experienced a safe and optimal recovery.

Materials