Cinereous vultures (Aegypius monachus) are large raptors in the family Accipitridae of the order Falconiformes. These are migratory birds that return to Mongolia after wintering in the Korean Peninsula (1,7). This species is registered as a natural monument designated by the Cultural Heritage Administration in South Korea and is protected by the Ministry of Environment as a second-grade endangered species (7). However, many cinereous vultures are distressed annually due to various causes such as poisoning, gunshot, collision, starvation, and exhaustion. Much of this distress has been attributed to toxicosis (6). Additionally, winter migratory birds, especially cinereous vultures, suffer from a lack of suitable wintering habitats and food sources in Korea (1).

In this case study, we rescued a cinereous vulture that fractured a bone after colliding with an electric wire. The bird was released back into the wild after fracture surgery using a shuttle pin and cerclage wire. A shuttle pin is a form of internal fixation made from polypropylene rods that works well on transverse or short oblique fractures of the ulna, tibiotarsus, and humerus (3,10). Intramedullary (IM) polymer rods (e.g., the plastic plunger of a syringe) may also be used as shuttle pins (2).

Two years and 4 months later, the cinereous vulture was rescued again due to pesticide poisoning. During its treatment, the bird’s previous fracture site was re-examined using radiography, showing that the radius fracture had healed completely and normally.

This is the first case in South Korea of treating a cinereous vulture’s radius fracture using a shuttle pin. Additionally, it provides important data that reaffirms the effectiveness of surgical operations using a shuttle pin.

A distressed cinereous vulture was rescued on a road from the Asan area in Chungcheongnam-do Province. It was admitted to Chungnam Wild Animal Rescue Center on February 24, 2015. External observations confirmed a problem in the bird’s right wing. The bird’s initial weight was approximately 7,620 g. The bird’s body condition score was 2 out of 5, it was mildly dehydrated, and had no intra-oral bleeding or a palpated crop. The cause of the distress was presumed to be a wire collision because many electric wires and poles were observed around the rescue site.

Blood was collected from the brachial vein to perform a basic biochemistry test. The blood test results were as follows: packed cell volume, 38%, which was lower than the normal range; glucose, 350 mg/dl; lactate dehydrogenase, 1,745 U/L, which was higher than the normal range. Based on these blood test results, stress, and muscle damage were considered (Table 1).

Table 1 . Basic biochemistry test of cinereous vulture.

Index	Result	Reference range	Unit
PCV	38	40-55	%
ALB	1.2	1.0-2.0	g/dL
ALKP	60	54-510	U/L
AST	244	< 300	U/L
Calcium (Ca++)	2.05	2-3	mmol/l
CK	711	< 1,000	U/L
GLU	350	200-300	mg/dL
LDH	1745	430-1,200	U/L
TP	3.5	2.5-4.5	g/dL
UA	4.3	2-15	mg/dL
GLOB	2.3	1.5-2.5	g/dL
Sodium (Na+)	146	145-155	mmol/l
Potassium (K+)	4.0	3.0-4.0	mmol/l

PCV, packed cell volume; ALB, albumin; ALKP, alkaline phosphatase; AST, aspartate amino transferase; CK, creatine Kinase; GLU, glucose; LDH, lactate dehydrogenase; TP, total protein; UA, uric acid; GLOB, globulin..

Radiographic examination confirmed a right proximal radius fracture with bone fragments (Fig. 1A). Swelling and hyperemia were observed in the soft tissue around the fracture site. The pain response of the right-wing suggested no nerve damage.

Figure 1. Right radius radiographs of the cinereous vulture. Radiographs show the right radius closed fracture in the cinereous vulture (A). Radiographs were taken to confirm that the shuttle pin and wire were properly and accurately after the operation (B). Post-operative 7th day (POD) (C). Radiographs were taken several times to confirm the fracture surgery site during the physical therapy POD 13th (D), POD 20th (E), POD 27th (F), POD 36th (G), POD 48th (H), and POD 55th before the release (I).

An intravenous catheter was inserted into the left brachial vein and Hartmann’s solution (50 mL/kg/day; Hartmann’s Sol, Daihan Pharm, Korea) was administered intravenously (IV) for rehydration. A figure of eight bandage was used to prevent further soft tissue damage and restrain wing movement. Piperacillin (200 mg/kg; Acopex^®, Yuhan, Korea) was administered IV and SID, and meloxicam (0.2 mg/kg; Metacam^®, Boehringer Ingelheim, Spain) was administered IM and SID.

Operation of the right radius closed fracture was performed the following day after the patient’s body condition stabilized. Isoflurane (Ifran^®, Hana Pharm, Korea) was used for induction and maintenance of inhalation anesthesia, followed by endotracheal intubation with a cuffless endotracheal tube (ID: 6.0 OD: 8.0). During the bird’s fracture surgery, its heart rate was monitored with an audio patient monitor (APM4000; A.M. Bicford Inc., USA) and its body temperature was checked using a digital thermometer. Anesthesia was induced with 5% isoflurane and maintained with 2-3% isoflurane in 100% oxygen at a flow rate of 2 L/min (Fig. 2A).

Figure 2. The cinereous vulture radius fracture treatment process. The cinereous vulture was anesthetized for fracture surgery (A). The shuttle pin (arrow) (B) was inserted in the right radius fracture site for operation (C). Physical therapy under inhalation anesthesia was performed 2 weeks after surgery (D).

The surgery was performed with the bird lying in a dorsoventral position on the operating table. The surgical site was disinfected to prevent bacterial infection, following general surgical disinfection procedures.

After making an incision at the skin over the fracture site, blood clots, tissue debris, and microbone fragments were removed from the inside of the radius fracture site using a sterile cotton swab. A 20 × 10 mm-sized fragment was identified at the fracture site. The muscle tissue and blood vessels near the fracture site had no severe damage.

Fracture reduction was performed using an IM non-absorbable shuttle pin, using a prepared 1 mm syringe plunger with a roll wire S/T 600 (Ø 0.3 mm) (Fig. 2B). The shuttle pin was inserted into the distal part at the fracture site. After aligning the fracture site, the wire connected to the plunger was pulled and inserted into the proximal part of the fracture. After confirming that the fracture site was aligned, the wire was removed (Fig. 2C).

The bone fragment was fixed using roll wire S/T 400 (Ø 0.5 mm). A continuous suture was performed using a 3-0 absorbable suture (Surgifit; Ailee co. Ltd, Korea) to close the incision site after realigning the incision line. Antibiotic ointment was applied to the suture site to prevent infection. To restrain the movement of the right wing, a figure of eight bandage was maintained for 2 weeks.

Oral medications, including 100 mg/kg clindamycin (Fullgram^®, SAMJIN, Korea) and 4 mg/kg carprofen (Rimadyl^®, Zoetis, USA) once daily, were prescribed for a week after surgery. Postoperative management was regularly performed with radiography and dressing to check for infection.

The figure of eight bandage was removed 2 weeks post-surgery. Passive range of motion exercise was performed twice weekly for approximately 7 weeks starting the day the bandage was removed (Fig. 2D). Physical therapy sessions, lasting no longer than 30 min, were conducted after administering inhalation anesthesia. To relieve pain, analgesic, meloxicam, was injected. Physical therapy began after applying a hot pack at 40°C for 10 min. The elbow joint angles were measured using a goniometer before and after physiotherapy sessions (Table 2).

Table 2 . Change of elbow joint angle according to physical therapy.

	POD 15	POD 20	POD 22	POD 27	POD 29	POD 34	POD 36	POD 41	POD 43	POD 48	POD 50	POD 55	POD 57
Before	61.3°	88.2°	95.5°	84.6°	106.5°	103.9°	105.9°	97.5 º	121.4°	114.5°	136.1°	111.7°	130.7°
After	88.9°	108.2°	113.7°	110.6°	124.1°	123.1°	124.5°	128.2°	133.2°	135.2°	147.5°	147.5°	153.1°

POD, Post-operation day..

Radiological examination was performed to check for infection from surgery or abnormalities from physical therapy (Fig. 1). At the end of the physiotherapy, the cinereous vulture was able to spread its right wing and recovered to a level where it could fly. However, it was placed under captivity in an outdoor flight cage by the end of the year because it was a winter migratory bird.

To identify this bird, a metal ring (150-00713) and wing tags (G/BL 3) were attached before its release. On October 31, 2015, the raptor successfully returned to nature in Seosan area.

Two years and 4 months later, on March 7, 2018, there was a report of distressed cinereous vultures in the Asan area. The cause of distress was presumed to be secondary pesticide poisoning based on circumstantial evidence of rice seeds and wild duck carcasses found around the rescue site. These cinereous vultures were salivating and unable to move. One cinereous vulture observed with a wing tag (G/BL 3; right-wing tag loss) and a metal ring (150-00713) was rescued in 2015 and returned to nature after a fracture operation (Fig. 3C).

Figure 3. Recaptured the cinereous vulture due to pesticide poisoning. Radiographs show the previously fracture operated (arrow) right (wing tag loss) (A) and left wing with wing tag (G/BL 3) (B). The cinereous vulture was rescued as the second pesticide poisoning and was admitted to the center (arrow) (C). The cinereous vulture was released after treatment (D).

For treatment, the crop was palpated to remove contaminated food. Atropine (Atropin sulfate inj, JEIL, Korea) and fluid therapy were administered. Two days after the treatment, the bird could stand. The intravenous catheter was removed the following day. No abnormal responses or movements were observed. During treatment, radiographs were undertaken to re-examine the previous operation site of radius fracture that was treated with the shuttle pin and wire (Fig. 3A).

The recaptured cinereous vulture had fast recovery and was released back to nature in the Seosan area 7 days after being rescued (Fig. 3D).

The basic principle of avian fracture reduction is to minimize soft tissue damage around the fracture site and stabilize its original form. In particular, the thoracic limb should be treated to avoid damage to muscles, tendons, ligaments, and joints (4,8). When operating on a bone fracture in a bird, surgery and treatment methods should be carefully selected based on the patient’s physical condition, species, size, and fracture type. Fractures can be treated in various ways using noninvasive methods (such as splints and bandages) or invasive methods (such IM pins, external skeletal fixators [ESF], shuttle pins, cerclage wires, and bone plates) (8,9,11).

A shuttle pin is a type of internal fixation used for transverse fractures or short oblique fractures of the ulna, tibiotarsus (10), and humerus (3). It is cheap, biologically inert, and does not need to be removed after healing (2,3,10). This method is vulnerable to rotational and bending forces. However, it is easier, faster to implement than other surgical methods, and it can align fractures well. Another benefit of the shuttle pin is that it minimizes potential problems that may occur from using IM pins and ESF. In terms of this case, the most suitable method to reduce the fracture and heal the fragment was using a shuttle pin and wire.

A shuttle pin is generally made of polypropylene rods. IM polymer rods (e.g., the plastic plunger of a syringe) may also be used as shuttle pins (2,10). In this case, a 1 mL syringe plunger was trimmed and used as a shuttle pin. Should the pin be too tight in the medullary cavity, endosteal bone necrosis may occur. In addition, fracture healing may be delayed or non-union might occur (10). Trimming the shuttle pin to the right size is essential to allow for movement within the bone cavity.

After the shuttle pin was completely inserted into the fracture site, the pin and fracture site were secured with eight-shaped wires to prevent the pin from moving inside the bone cavity and fracture site from separating or rotating (2,3). When fixing the fracture site with wire, one part of the fracture site passed through the shuttle pin and bone, and the other passed only through the bone and out of the pin, then it was secured with wire (2,3). In this case, the shuttle pin was fixed to the radius cavity and did not move. Thus, an eight-shaped wire was not used. The bone fragment was approximately 20 mm and was attached to the fracture site using a wire.

Generally, physiotherapy should begin 3-4 days post-surgery (10). In this case, physiotherapy commenced approximately 2 weeks post-surgery. Before physical therapy, callus formation at the fracture site was confirmed through radiography. Additionally, it was confirmed that there was no movement in the fracture area through palpation. However, it is recommended to select an appropriate time to start physical therapy depending on the location of the fracture, surgical method, and the animal’s health condition.

Generally, during physical therapy, the elbow joint angle should ideally ≥ 140°, and the wrist joint should extend to 180° (10). The elbow joint angle was measured with a goniometer before and after physiotherapy on the humerus and ulna. The angle of the carpal joint was not recorded because it was measured at almost 180° when first measured. As the physiotherapy began, the range of motion of the elbow joint gradually increased. After the final physical therapy session, the joint was stretched to almost normal condition.

After treating the re-rescued cinereous vulture for secondary pesticide poisoning, the attachment site of the wing tag was confirmed. The left-wing tag was still attached, but the right-wing tag was lost. However, no hole was found at the wing membrane of the confirmed attachment site of the right-wing tag. It was presumed that it healed naturally after the wing tag was lost. The operated right radius was compared with the normal left radius by radiographs. The results showed that the fractured part that was previously operated on was almost normal.

To treat a fracture, it is necessary to accurately assess the size and health of the bird. The most appropriate surgical method should be carefully selected according to the fracture site, fracture type, and time after fracture (5). As fracture surgery is just one of the treatment options, more systematic progression for postoperative management and physical therapy is needed to reduce the recovery time of the operated bird and provide more opportunities for its release

A fracture operation was performed on a cinereous vulture rescued for proximal radius fracture using a shuttle pin and wire. After successful physiotherapy and rehabilitation, the cinereous vulture recovered to normal flight capability and returned to nature that same winter. However, 2 years and 4 months later, the cinereous vulture was rescued again due to secondary pesticide poisoning. During its treatment, radiographs showed that the previous fracture operation site was in a completely normal state upon examination. Considering that the cinereous vulture, a winter migratory bird, travels long distances, this case marks the first confirmed success of this surgical method using a shuttle pin. Additionally, this provides important data to reaffirm the effectiveness of surgeries utilizing shuttle pins, as evidenced by radiographs. This case will serve as a valuable reference for wildlife veterinarians treating radius fractures in cinereous vultures.

This research was supported by a fund (Z-1543081-2019-21-01) by Research of Animal and Plant Quarantine Agency, South Korea.

No conflicts of interest have been declared.