Foreign body removal by standing thoracotomy in a dairy cow

Abstract

A three-year-old Holstein-Friesian cow presented at University College Dublin Veterinary Hospital with clinical signs of chronic weight loss, abnormal stance, slight arching of the back and increased left cranioventral lung sounds. Traumatic reticulitis, following the ingestion of a foreign body, was suspected. Radiographs showed the presence of a wire that had perforated the diaphragm and penetrated cranially into the thorax. Ultrasonographic findings included hyperechogenic areas mainly cranioventrally on the left side of the thorax as well as changes indicative of lung consolidation. A standing left thoracotomy to remove the wire was successfully performed under standing sedation and regional anaesthesia. This involved the removal of a portion of the sixth rib to facilitate surgical access. A drainage tube was placed in order to manage the subsequent temporary unilateral pneumothorax. The cow recovered very well postsurgery, went back to the farm and calved four months later.

Correspondence to Eoin Gerard Ryan; [email protected]

Background

Traumatic reticuloperitonitis (TRP), often known as Hardware disease, is a relatively common disease of cattle in many countries around the world. It is caused by penetration of the wall of the reticulum, either partially or completely, by fragments of metal or sharp plastic material inadvertently eaten by cattle, with resultant adhesion formation or abscessation in the perireticular region.¹ The reticulum is the smallest of the forestomach compartments, and it is positioned in the left cranioventral abdomen of the cow between the 7th and 10th ribs, in direct apposition to the abdominal surface of the diaphragm.^{2 3} Contractions of the reticulum form part of the primary cycle of the reticulorumen, the so-called ‘mixing cycle’ and are comprised of biphasic contractions, with the first phase pushing larger particles back into the rumen and the second phase involving a whole-organ contraction that moves ingesta into the abomasum.⁴

Traumatic reticulitis mostly affects adult dairy cattle and, less commonly, beef cattle.⁵ It is classically associated with the ingestion of wire from old tyres that are commonly used on silage pits to weigh down the cover. In more recent times, many cases have been associated with building work and the ingestion of nails, screws and other similar foreign bodies.⁶ Other risk factors include the ingestion of fencing wire following hedge clipping, total mixed ration feeding, pica, large and sloping silage clamps, bonfires on grazing land and untidy farms with tyres and debris near the feed face that may enter the feed.¹ The exposure of the whole herd to an excessive amount of metallic material can potentially trigger multiple cases of traumatic reticulitis. Veterinary surgeons dealing with outbreaks of traumatic reticulitis should consider a number of preventative measures. These include the administration of ruminal magnets to all cows and heifers on the farm, proactively removing all suspect tyres and reviewing the dietary components fed to cows to minimise the ingestion of metallic objects.¹ Placing reticular magnets has a dual function in both the prevention and treatment of hardware disease.⁶ Ensuring that magnets are present and functional in cattle feeder wagons and on silage making/harvesting equipment is also of paramount importance.

Ingestion of a foreign body can have five different potential outcomes: (1) small foreign bodies, for example, pieces of wire, may sit in the ventral reticulum without causing any clinical signs; (2) metallic foreign bodies may attach to a previously administered magnet without development of clinical disease, (3) penetration of the reticular wall without entering the peritoneal cavity, causing focal reticulitis and mild clinical disease, (4) perforation of the reticular wall and entrance to the peritoneal cavity causing acute localised reticuloperitonitis or (5) perforation of the reticular wall and entrance to the peritoneal or thoracic cavity resulting in pericarditis, myocarditis, abscessation (perireticular most commonly; also pleural, hepatic and splenic), vagal indigestion or other secondary disease, for example, acute haemorrhage. The majority of clinical cases involve localised perireticular adhesions and peritonitis. Abdominal and thoracic abscesses associated with Hardware disease involve bacteria including Truepurella pyogenes primarily, as well as Fusobacterium necrophorum and Clostridium spp.²

There are two approaches that can be considered for the treatment of Hardware disease: conservative management and surgical intervention. Conservative management involves four components: (1) confinement, (2) pain relief, (3) antibiosis and (4) the administration of a magnetic bolus. Restricting movement is essential to prevent migration of the wire cranially and analgesia will greatly speed recovery. In relation to antibiotics, treatment using penicillin, or potentiated penicillin, for an extended period of time of not less than seven days is indicated.¹ While traumatic reticuloperitonitis is generally a chronic disease, acute and severe cases do occur and can lead to generalised septic peritonitis followed by hypovolaemic shock requiring intensive fluid therapy.⁵

However, while conservative management may be successful for less severe cases, surgery is the gold standard treatment for cattle with foreign bodies that penetrate or perforate the reticulum,¹ particularly where it can be demonstrated radiographically that conservative treatment has failed, that is, a portion/all of the foreign body remains outside the reticular wall despite the introduction of a magnet into the reticular lumen. Undoubtedly, euthanasia must also be considered in severe cases and for animals of low financial value.

Surgery involving the lung or mediastinal structures is rarely indicated in cattle, and foreign body penetration of the thorax from the reticulum is relatively rare. The cranial rib cage of cattle has limited compliance and, therefore, exposure of the cranioventral and caudoventral thorax requires rib resection. This is most commonly done for treatment of traumatic reticulopericarditis or reticulopleuritis. This surgery may be performed either standing with sedation and local anaesthesia, with the cow restrained on an inclined table and using sedation and local anaesthesia or with the cow under general anaesthesia.²

Removal of a foreign body by thoracotomy in a standing bovine, using standing sedation, local anaesthesia and rib resection, is described in only one other publication,⁷ although standing thoracotomy and diaphragmatic herniorraphy in a cow has been described.⁸ This case report describes the successful removal of a foreign body by standing thoracotomy providing a template for veterinary surgeons, either in practice or in referral hospitals, who may have to deal with similar presentations.

Case presentation

A three-year-old Holstein-Friesian cow was referred to University College Dublin Veterinary Hospital (UCDVH) on September 24, 2018. She had a non-eventful calving in February, but from the following May, she had started losing body condition despite having a good appetite. She failed to respond to routine antibiotic treatment by the referring veterinarian, as well as the administration of two magnetic boluses.

Investigations

On arrival, the cow was quiet but alert and responsive. When in the crush, she displayed an abnormal stance with her hind limbs stretched caudally in an exaggerated manner suggestive of abdominal pain and discomfort. Body temperature (38.2°C), heart rate (60 beats per minute (bpm); normal range: 60–84 bpm)⁹ and respiratory rates (30 breaths/min; normal range: 15–35 breaths/min)⁹ were within normal limits. On auscultation, lung sounds were increased cranioventrally on both sides but more pronounced on the left side. In addition, there was bilateral mucoid nasal discharge, also more pronounced on the left side. The Wither’s test was negative; that is, the cow dipped her back in a normal manner in response to manual pressure applied by pinching the dorsal spinal processes caudal to the withers and no grunt was heard. The Williams test (where the clinician auscultates the trachea for a grunt in association with reticular contraction before ventral ruminal and dorsal sac contraction) and the xiphoid test (where a pole is raised under the sternum to assess for pain in the reticular region) were not performed. Both the rumen and reticulum were found to be hypomotile, with one weak primary cycle heard on auscultation per minute. Faeces were scant and not well digested, and there were no abnormalities on rectal examination. The cow had poor gut fill, and abdominal contour was not suggestive of vagal indigestion syndrome. The cow was confirmed to be five months pregnant.

A complete haematology and biochemistry blood panel was taken. The abnormal findings were hyperproteinaemia (total protein 101.0 g/l; laboratory reference range 67–85 g/l) and hyperglobulinaemia (globulin 75.9 g/l; lab. ref. range 31–55 g/l) indicating the presence of a chronic inflammatory process, which is found with many conditions including chronic abscessation, peritonitis and conditions with thrombus formation, for example, endocarditis and posterior vena caval thrombosis. Lymphopenia (lymphocytes 2.12×10⁹/l; lab. ref. range 2.75–8.0 × 10⁹/l) was apparent, a common leucogram abnormality often associated with stress but also associated with issues such as viral infections. All the other parameters were within normal limits. Given the respiratory findings on clinical examination, a bronchoalveolar lavage was carried out, and some floccules of pus or exudate were present in the sample taken. This sample was not submitted for culture or cytology. Ultrasonography of the lungs was performed using a Sono-site M-Turbo Scanner with a linear HFL38x probe at a frequency range of 6–13 MHz. Comet tail artefacts and lung consolidation were identified, particularly cranioventrally on the left side. Reticular motility was further assessed using ultrasonography, with the transducer placed just caudal and slightly lateral to the xiphoid process directly underneath where the normal reticulum lies. The reticulum was observed for two minutes without moving the transducer. Triphasic contractions were evident, and there was some abnormal hyperechogenic material present between the reticulum and rumen. Standing digital lateral thoracic radiographs, centred over the reticular region immediately caudal to the left elbow, were subsequently taken due to the suspicion of Hardware disease at this point. Heterogeneous material of mineral and soft tissue opacity was found within the ventral aspect of the reticular lumen and considered as a normal finding. A curvilinear structure of metallic radiopacity was found to be superimposing the soft tissues immediately cranial to the cranioventral aspect of the reticulum (figure 1). Additionally, multiple foci of gas radiopacity were located dorsally to the caudal half of the metallic structure. Two gas radiopacities had straight, horizontal, soft tissue ventral margins suggestive of fluid lines and abscess formation. A diagnosis of traumatic reticulitis, with penetration of the cranial wall of reticulum by a metallic foreign body, was made. It was clear that the wire had completely penetrated the diaphragm and was entirely within the thorax (figure 1), leading to thoracic abscessation. A decision was taken to surgically remove the wire via standing left sided thoracotomy.

Figure 1. It can be clearly seen that the metallic foreign body (A) is lying in the thorax cranial to the reticulum (B=cranial wall of the reticulum). Dorsally, there is a small area of abscessation characterised by a fluid line and gas opacities (C). Figure part D corresponds to the left elbow.

Differential diagnosis

Differential diagnoses for initial presentation of chronic weight loss despite good appetite included chronic abscessation, peritonitis, cardiac disease, for example, endocarditis, protein losing enteropathy, protein losing nephropathy and liver disease. Differential diagnoses following ultrasonography of the lungs and reticulum included chronic bronchopneumonia with or without pleuritis, reticuloperitonitis and cranial abdominal peritonitis (ruptured liver abscess; perireticular abscess; and localised abomasal perforation). Following radiography, our final diagnoses of traumatic reticulitis with an associated thoracic foreign body, pulmonary abscessation and pleuritis were apparent.

Treatment

As premedication, the cow was given 8 mg/kg of procaine penicillin plus 10 mg/kg dihydrostreptomycin sulphate (Pen&Strep, Norbrook Laboratories Ltd) intramuscularly, as well as 0.5 mg/kg of meloxicam (Loxicom, Norbrook Laboratories Ltd) intravenously. Surgery was performed under standing sedation using 0.01 mg/kg (0.6 ml) detomidine (Detonervin 10 mg/ml, Le Vet B.V.) intravenously, followed 40 min later with a lower dose of 0.005 mg/kg (0.3 ml) detomidine. This lower dose was combined with a modified ketamine stun technique of 0.05 mg/kg (1.5 ml) xylazine 2 per cent (Sedaxylan 20 mg/ml, Eurovet Animal Health B.V.) and 0.25 mg/kg (1.5 ml) ketamine (Anaestamine 100 mg/ml, Le Vet Beheer B.V.), both injected intramuscularly. The cow received one further additional sedation using the modified ketamine stun technique at a dose of 0.033 mg/kg (1 ml) of xylazine 2 per cent and 0.17 mg/kg (1 ml) of ketamine intramuscularly, administered 30 min following the initial stun. Sedation was administered in accordance with patient behaviour. The modified stuns were injected intramuscularly for ease of administration and increased longevity of action.

Surgical technique

An area of the left thorax extending caudally from the level of the xiphoid to the 10th intercostal space and dorsally to the level of the tuber coxae was clipped. The skin was prepared aseptically for surgery by scrubbing and washing with a chlorhexidine gluconate 4 per cent solution (Hibiscrub), followed by surgical spirits. The sixth rib was identified by counting forward from the last rib, and 120 ml of 2 per cent procaine with epinephrine (Pronestesic 40 mg/ml, FATRO S.p.A.) was infused in a line block along the lateral aspect of this rib. An additional total volume of 120 ml of local anaesthetic was infused into the cranial and caudal intercostal spaces proximal and distal to the proposed surgical site. Following final surgical skin preparation, a skin incision was made over the sixth rib, starting from 10 cm dorsal to the costochondral junction, and extending dorsally for approximately 20 cm. The underlying muscles (latissimus dorsi, serratus ventralis thoracis, deep pectoral and external abdominal oblique) were incised, and the rib was exposed. The periosteum over the rib was elevated allowing obstetrical wire to be passed around the rib at the proximal and distal aspects of the incision. This portion of the rib was transected and removed (figure 2). Then the periosteum and parietal pleura were incised to expose the caudoventral thorax. Respiratory rate increased to 50 breaths per minute at this point, due to unilateral pneumothorax, but grunting or signs of respiratory distress were not evident. An abscess was found between the body wall and the left caudal lung lobe. Careful manual exploration of the area allowed the identification of the foreign body that was surrounded by adhesions and adjacent to the thoracic abscess identified on the radiographs. The metallic foreign body, an 8 cm length of heavy tyre wire (figure 3), was removed, and the abscess was drained using suction. After lavage of the left hemithorax had been performed using 5 l of sterile saline, a size 24 French thoracostomy tube with a clamp was placed dorsally through a stab incision in the ninth intercostal space, approximately level with the middle of the left paralumbar fossa and the thoracotomy incision closed. Pleura, periosteum and intercostal muscles were closed in one simple continuous layer using absorbable suture material (PDS 0); the muscles overlying the thoracic wall were also closed in one layer using absorbable suture material (PDS 2); and the skin was closed routinely using non-absorbable interrupted sutures of 6-metric synthetic polyamide (Supramid). The free air remaining in the thorax was aspirated via the drainage tube, and a Heimlich valve was placed on the open end of the tube (figure 4). The use of this kind of valve allowed continuing air escape without compromising thoracic pressure.

Figure 2. Section of the sixth left thoracic rib that was transected to facilitate access to the thoracic cavity.

Figure 3. Eight centimetre long metallic foreign body removed from left thoracic cavity.

Figure 4. Stent placed over the thoracic incision site at the level of the sixth intercostal space; drain placed dorsally in the ninth intercostal space with a clamp to allow removal of air from the left hemithorax.

Postoperative management

The cow received 20 litres of water orally with 200 ml of propylene glycol (Chanatol, Chanelle Veterinary Ltd). She was placed on an antibiotic course of penicillin-streptomycin (8 mg/kg of procaine penicillin plus 10 mg/kg dihydrostreptomycin sulphate (Pen&Strep, Norbrook Laboratories Ltd)), intramuscularly, twice daily for one week and once daily for another week. She also received meloxicam (Loxicom, Norbrook Laboratories Ltd), 0.5 mg/kg, subcutaneously 24 hours postsurgery and again 48 hours later as pain relief. Recommended meat and milk withdrawals related to these treatments were adhered to, including extended default withdrawals (seven days milk and 28 days meat withdrawal) to account for the twice daily penicillin-streptomycin, which was off-label use. The cow was examined twice daily and assessed for respiratory function, wound healing, appetite and pain level. Respiratory rate was 36 breaths/minute at 24 hours postsurgery and 30 breaths/minute by 48 hours postsurgery. She was maintained on a diet of hay and 4 kg concentrates per day. Feed intake was reduced for 24 hours postsurgery, likely due to pain, as indicated by a heart rate of 84 bpm at 24 hours postsurgery. However, by 48 hours postsurgery, heart rate was 64 bpm, her feed intake had returned to normal, her rumen motility was good and she was noted to be chewing the cud. The thoracic drain was removed four days postsurgery when negative pressure was achieved indicating that the pneumothorax was resolved. The skin was closed using a cruciate pattern with PDS 0. The cow was hospitalised for eight days postsurgery before returning home.

Outcome and follow-up

The cow recovered very well from the surgery. Her appetite was consistently good with satisfactory intakes of hay and concentrates, and her faeces had a better consistency than before surgery. The average milk yield was 4 l per day before surgery and did not rise appreciably during the postoperative period while the cow was in the hospital. The surgical site remained clean, with no signs of infection, swelling, heat or discharge, and skin sutures were removed three weeks postsurgery. The cow returned to the farmer’s herd and calved down 4.5 months later in good body condition. Longer term follow-up was not possible due to a whole herd dispersal.

Discussion

This case report describes the successful removal of a thoracic foreign body, secondary to traumatic reticulitis, using a standing thoracotomy approach. This is an uncommon presentation of Hardware disease, and the authors have endeavoured to detail the diagnostics and treatment involved.

There are a number of challenges related to successful diagnosis of Hardware disease. Clinical signs vary depending on the nature of the metallic fragments ingested, and on the organ penetrated by the foreign body, but are often very vague and easily overlooked. Acute/subacute ruminal tympany is usually present in the early stages of traumatic reticuloperitonitis but can easily be missed by an unobservant stockperson. Additionally, the use of antibiotics and/or non-steroidal anti-inflammatory drug (NSAIDs) by farmers at the initial stages of the disease often masks disease progression, making clinical recognition more difficult. In the early stages, many cases present with fever of unknown origin. If the perforation is recent, clinical signs can include anorexia, milk drop greater than 50 per cent in 24 hours, abdominal pain, reduced ruminal activity, firmer faeces, grunting and peculiar lying positions.¹ If the problem becomes chronic, there can be loss of body condition, an arched back posture, abdominal tension, reduced ruminal motility and reduced faecal output with an increase of undigested particles. Chronic cases are often associated with ruminal distension or with signs of vagal indigestion syndrome¹⁰ and a ‘papple’ (L-shaped) abdominal contour might be seen.⁵

In this particular case, the local veterinarian did suspect Hardware disease despite the lack of clinical improvement following the administration of two magnets on farm. In hindsight, this lack of improvement can be explained by the fact that the wire had penetrated the reticular wall and migrated to the thorax. History, clinical signs, ultrasound and response to therapy are the primary diagnostic methods available for the field veterinarian. One common clinical examination technique that is used for the diagnosis of traumatic reticuloperitonitis is the Wither’s test. The Wither’s test involves the application of manual downward pressure by pinching and simultaneously pressing down on the dorsal spinous processes immediately caudal to the withers of the affected animal at height of inspiration. A normal response involves the animal dipping their back away from the withers pinch. If pinching the withers elicits a pain response, that is, the animal does not dip their back and displays signs such as bruxism, salivation or grunting, it is suggestive of painful pathology primarily in the cranial abdominal region that incorporates the perireticular area and also in the diaphragm caudal thoracic region.¹¹ Interestingly, the Wither’s test was normal in this case, probably as a result of the foreign body and associated pathology being in the thorax. However, some studies confirm that the sensitivity of the Wither’s test is low with only 39 per cent of reticuloperitonitis cases displaying an abnormal/positive response.¹¹ It must be remembered that to elicit grunting in cattle with chronic traumatic reticuloperitonitis, considerable strength may be required when conducting foreign body tests, and in cows with chronic localised peritonitis, the Withers test may be positive, negative or equivocal.¹¹ Other pain tests that are commonly used in the diagnosis of Hardware disease include the Williams test, xiphoid/pole test, percussion of the abdominal wall over the region of the reticulum with a rubber hammer and the knee/fist test that involves applying a sudden upward force with the knee or fist in the area of the xiphisternum.¹² The Williams test is a well-regarded clinical examination technique for the diagnosis of TRP and may be more sensitive than the Wither’s test for the early diagnosis of Hardware disease. However, it cannot be performed if there is rumenostasis.¹³ The Williams test involves positioning a stethoscope over the cow’s trachea and a hand on the left paralumbar fossa to detect ruminal movement; a quiet and normally inaudible grunt may be heard just before the start of the ruminal contraction. The grunt is due to pain elicited by the double reticular contraction that causes the penetrating foreign body to produce visceral peritoneal irritation.¹³ The xiphoid/pole test involves the application of upward pressure on the anterior abdomen to check for discomfort and associated grunting. A padded metal or wooden bar is placed beneath the animal and positioned just behind the xiphisternum. The bar is slowly raised and then lowered quickly to elicit a grunt. The xiphoid/pole test has higher sensitivity (43 per cent) than percussion using a rubber hammer, which has a sensitivity as low as 24 per cent.¹¹ In practice, it is advisable to combine a number of techniques to increase the likelihood of a positive diagnosis. Additional techniques include pushing the rumen cranially by rectal examination, which is often resented or elicits a grunt or catch in respiration in cases of TRP.

In a hospital environment, the use of advanced diagnostic imaging techniques, including ultrasonography and radiography, aids considerably in decision making around conservative versus surgical management. When radiography or ultrasound are used alone, each of them has limitations for the diagnosis of reticulitis, but they are excellent tools when combined.¹¹

Ultrasonographic examination is useful to determine the association of abscesses with vital structures, to search for foreign bodies and to determine the extent of lesions before surgery.² The most common ultrasonographic findings in cattle with traumatic reticulitis relate to inflammatory changes involving the peritoneum in the reticular area. Proliferative inflammatory changes of the reticular serosa, that is, the presence of fibrin tags and echogenic contents between the reticulum and rumen, indicate at least transient complete perforation of the reticular wall by the foreign body. In this case, the finding of hyperechogenic contents in the rumenoreticular recess was suggestive of Hardware disease and prompted progression to the use of radiography. A decrease in the amplitude of reticular contractions is the second most common abnormal ultrasonographic finding.¹¹ The frequency and amplitude of reticular contractions are almost always abnormal in cows with traumatic reticulitis, but the biphasic contraction pattern of the reticulum is usually maintained.¹⁴ In this case, ultrasonography revealed triphasic reticular contractions that was also suggestive of TRP. Reticular abscesses can be picked up on ultrasound and are characterised by an echogenic capsule of varying thickness with a central hypoechoic cavity.¹⁴ Metallic foreign bodies, however, are rarely visualised using ultrasonography. Radiographic examination is indicated when physical examination and ultrasound have isolated the disease to a specific area but cannot sufficiently determine the nature or severity of the disease.

Radiography is the method of choice for visualisation of ferromagnetic foreign bodies and magnets in the reticulum of cattle. The diagnostic sensitivity of radiography for detection of traumatic reticuloperitonitis ranges from 71 per cent to 83 per cent, and the specificity varies from 82 per cent to 90 per cent.¹⁴ The radiographic position of a reticular foreign body relative to the contour of the reticulum is of diagnostic significance. Foreign bodies that contact the ventral aspect of the reticulum or foreign bodies at an angle of less than 30° to the ventral aspect of the reticulum have most likely not penetrated the reticular wall. Similarly, foreign bodies lying flat on the floor of the reticulum or attached to a magnet usually have not perforated the reticulum. The same is true for foreign bodies that have different positions on multiple radiographs, as this indicates that they are able to move freely within the reticular lumen. In contrast, foreign bodies observed partially or entirely outside of the reticulum have perforated the reticular wall. Gas shadows or gas–fluid interfaces (fluid lines) near the reticulum strongly suggest perforation of the reticulum by a foreign body and subsequent abscess formation.

In this case, it was clearly seen that the foreign body was within the thorax and associated with localised thoracic abscessation. Thoracic abscesses are usually unilateral and, if sizeable enough, result in detectable absence of lung sounds in the affected ventral hemithorax. Ipsilateral heart sounds may be absent or muffled, whereas contralateral heart sounds may be louder than normal and accentuated. Fever unresponsive to antibiotics, progressive dyspnoea, ventral oedema and reluctance to move are sometimes observed in cattle with lung abscesses.¹⁵ In this case, there was evidence of fibrinous adhesions and lung consolidation on ultrasonography. However, it was decided that surgical intervention was the optimal approach to take in order to maximise the chances of the cow making a meaningful recovery.

Some laboratory blood tests can also be helpful in the diagnosis of TRP, especially particular haematology and biochemistry markers. Total white cell count can be an aid to diagnosis, with leucocytosis often prominent in cases where large intra-abdominal or intrathoracic abscesses develop and leucopenia present in some cases. Similarly, differential white cell count can be a diagnostic aid revealing neutrophilia and left shift in animals with traumatic reticulitis. Haematological changes, however, are not pathognomonic, and similar changes can be seen in many other inflammatory and infectious conditions. However, as in the case of the cow described in this report, normal neutrophil levels are often seen, particularly in chronic cases. Biochemistry markers of diagnostic importance include raised total protein, hyperglobulinaemia and increased fibrinogen.^{1 16} Hyperfibrinogenaemia and hyperproteinaemia are better indicators of TRP than leucocyte counts.¹² Fibrinogen may be increased as early as two to three days after the onset of TRP, and in cases of chronic TRP, total protein concentration is commonly increased due to an increase in globulin concentration.¹² The glutaraldehyde coagulation test is a simple and rapid point-of-care method for semiquantitative determination of γ-globulin and fibrinogen concentrations and can be useful in the diagnosis of TRP.^{12 17} In animals with TRP, haptoglobin concentrations have also been described as significantly higher than normal.⁵

Removal of a foreign body by thoracotomy in a standing bovine, using standing sedation, local anaesthesia and rib resection, is described in only one other publication.⁷ In that case series, outcomes were much more favourable when standing thoracotomy was performed to remove foreign bodies involving lung abscess/pleuritis than general anaesthetic approaches and compared with cases involving septic pericarditis. The surgical option of standing thoracotomy is favoured by the thoracic anatomy of the bovine as the mediastinum completely separates the left and right sides of the thorax. This means that although a unilateral pneumothorax will inevitably occur following thoracotomy, a bilateral pneumothorax, which would likely result in death without inhalational anaesthesia, is avoided.¹⁸ Management of unilateral pneumothorax should be considered postsurgery. While mild cases of pneumothorax in cattle may resolve without the need for intervention, severe unilateral or bilateral pneumothorax carries a high risk of acute death and necessitates intervention.¹⁹ The management of unilateral pneumothorax is successfully described in this case report using the Heimlich valve approach.

In relation to the surgical approach in this case, a number of factors were considered including the economic value of the cow, achieving good access to the location of the foreign body within the thorax, the ease of the anaesthetic approach and the probability of success with each option. It was felt that a standing thoracotomy approach using sedation and local anaesthesia would provide sufficient restraint, analgesia and access for a successful surgery to be performed without excessive economic expenditure. This was found to be the case. In contrast, inhalational general anaesthesia in farm animals is an involved and expensive procedure with potential negative side effects including regurgitation, aspiration pneumonia, ruminal tympany, hypoventilation and hypoxaemia. Delivery of an inhalation anaesthetic also requires expensive and specialised equipment. Injectable general anaesthesia also has a high risk of negative side effects and was felt to be unsuitable in a surgery such as this where unilateral pneumothorax would be induced. In this case, the use of standing sedation using a combination of detomidine and a modified ketamine stun provided reliable and efficient sedation and restraint. The cow did not react in a painful manner to incision of the pleura or handling of the thoracic abscess and foreign body. In contrast to the classical ketamine stun,²⁰ the modified ketamine stun involves using an α2-agonist (xylazine 2 per cent) and ketamine without the use of the opioid butorphanol. The main driver for the use of the modified ketamine stun was the restriction on the use of opioids in cattle within Ireland and the European Union (EU). Anaesthetic protocols, such as the ketamine, or modified ketamine, stun, are beneficial in that when drugs are combined, clinicians are able to use smaller doses of the individual components while still achieving the desired level of effect.²⁰ Compared with general anaesthesia, ease of drug administration, minimal equipment requirements, low cost, shorter recovery time and reduced potential for complications are advantages that should make these techniques attractive to general veterinary practitioners, particularly those who often carry out surgical procedures on farm.²¹ The restriction on the use of opioids in farm animals within the EU was also one of the main factors determining our choice of analgesia in this case, with NSAIDs considered to be the most practical and suitable option. We were happy overall with the level of analgesia and pain management provided and the cow’s comfort level postsurgery. Certainly, she was noted to be painful for 24 hours postsurgery but improved quickly after this.

Rib resection and thoracotomy allows exposure of the caudal lung lobes and mediastinum. Different indications for thoracotomy, for example, drainage of the pericardium in a case of reticulopericarditis, may necessitate a different location for rib resection. However, disruption of the vagus and phrenic nerves, the caudal vena cava, descending aorta or oesophagus are undesirable outcomes that must be avoided when performing surgery of the thorax.² In contrast to Ducharme and others,⁷ we did use a drain with a Heimlich valve to resolve the unilateral pneumothorax postsurgery. Using this approach, pneumothorax was not evident four days postsurgery.

In conclusion, standing thoracotomy under sedation and local anaesthesia is a viable option for the removal of foreign bodies from the thorax. The importance of diagnostic radiography for decision making in relation to conservative or surgical management of cases of Hardware disease cannot be underestimated. It is important for practising veterinarians to be aware of the lack of sensitivity of the Wither’s test, and other pain tests, in the clinical diagnosis of Hardware disease. Traumatic reticulitis is a disease of major importance and is still common in large expanding dairy farms. Routine control measures, particularly involving the use of prophylactic magnetic boluses, should be considered in problem herds.

Learning points

• Standing thoracotomy under sedation and local anaesthesia is a viable option for the removal of foreign bodies from the thorax.

• The importance of diagnostic radiography for decision making in relation to conservative or surgical management of cases of Hardware disease cannot be underestimated.

• It is important for practising veterinarians to be aware of the lack of sensitivity of the Wither’s test, and other pain tests, in the clinical diagnosis of Hardware disease.

• Traumatic reticulitis is a disease of major importance and is still common in large expanding dairy farms.

• Routine control measures, particularly involving the use of prophylactic magnetic boluses, should be considered in problem herds.

We would like to acknowledge the efforts of all the Farm Animal Clinicians, members of the surgical team and yard staff in UCD, as well as the referring veterinary practitioner and owner.

Footnote

Contributors JD and EGR were the principal authors of the paper with help on sections and with the overall review of the manuscript by the other authors. All authors were directly involved in the work-up, diagnostic imaging, surgical management and medical management of the case.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests None declared.

Provenance and peer review Not commissioned; externally peer reviewed.

Data availability statement All data relevant to the study are included in the article.

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