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Surgery of the Upper Respiratory System
Vet Clin Food Anim 24 (2008) 319–334
Surgery of the Upper Respiratory System David E. Anderson, DVM, MSa,*, Guy St. Jean, DMV, MSb a
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, 1800 Denison Road, Manhattan, KS 66506, USA b Ross University School of Veterinary Medicine, P.O. Box 334, Basseterre, St. Kitts, West Indies
Surgery of the respiratory tract often is considered a last resort. However, these surgeries can be performed successfully, allowing for preservation of genetics and productivity. This article discusses surgery of the upper respiratory system. Aspects of physical, radiographic, endoscopic, and ultrasonographic examination are explored. Conditions of the nares, paranasal sinuses, nasopharynx, palate, nasolacrimal duct, pharynx, and larynx are covered. Physical examination Physical examination of the respiratory system of cattle may be difficult, depending on the nature of the animal [1–4]. Halter-trained cattle are certainly easier to examine than cattle accustomed to the open range. A complete physical examination is critical to thorough work-up of cattle affected with respiratory disease. Determination of the location and severity of the disease is of utmost importance to the surgeon, and helps to narrow the list of differential diagnoses. The character, frequency, and depth of respirations should be noted. The thorax, trachea, larynx, and paranasal sinuses should be ausculted separately to identify the point of maximal intensity of abnormal sounds. The nares should be felt to determine symmetry of air movement and depth of respiration in proportion to the size of the animal. The head should be examined for symmetry and position relative to horizontal. Thoracic auscultation should be performed for all lung fields on both sides of the thorax. Thoracic acoustic percussion can contribute significantly to the information database, particularly when thoracic radiographs and ultrasonography are not available [5]. Acoustic stethoscopes may aid in * Corresponding author. E-mail address: [email protected] (D.E. Anderson). 0749-0720/08/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.cvfa.2008.02.003 vetfood.theclinics.com
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diagnosis of thoracic disease. Hematology and serum biochemistry analysis may be indicated to characterize the nature or severity of a given disease. These tests are chosen after determining economic constraints and when interpretation is believed to be beneficial for guiding therapy or prognosis. Radiographic examination Radiographic examination is indicated when physical examination has isolated the disease to a specific area but cannot sufficiently determine the nature or severity of the disease. Radiographs are useful for evaluation of the skull, trachea, and thorax because the surrounding air density allows detection of soft tissue pathology. Also, lesions may be localized to a specific segment of the respiratory system (eg, sinusitis, retropharyngeal abscess, pulmonary abscess, pericarditis). CT of the thorax has been used by the author to detect disease that is not apparent on radiographs. This technology is limited to calves, small ruminants. or the skulls of adult cattle. Endoscopic examination When possible, chemical restraint should not be used to facilitate endoscopic examination because significant alteration of the endoscopic anatomy may occur [6,7]. A 1-m long endoscope is sufficient to view the nasal passages, pharynx, larynx, proximal trachea, and esophagus of most adult cattle. The accessory bronchus can be viewed in most animals less than 700 kg, but a 3-m endoscope may be necessary for examination of the mainstem bronchi and the full length of the esophagus. The upper airway anatomy of cattle differs from that of horses. The examiner should be familiar with bovine anatomy. Pigmentation of the pharynx and larynx is not uncommon in cattle, and pigmented areas should not be misinterpreted as pathologic tissues [6]. Ultrasonographic examination Ultrasonographic examination of the ventral neck and mediastinum has been described for cattle [8,9]. These examinations may be useful to determine the association of abscesses with vital structures, search for foreign bodies, and determine the extent of lesions before surgery. Interpretation of ultrasonographic images is directly proportional to the examiner’s knowledge of bovine anatomy and experience level. In one study, thoracic ultrasonography was more sensitive than radiographs for detection of small pleural effusion and pulmonary consolidation [10]. Nares Minor surgical procedures and insertion of nose rings are often performed on cattle [11,12]. A nose ring is often applied in cattle that are
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routinely handled, and is helpful during examination of the head, application of tattoos or tags, and minor surgical or medical procedures. It is the authors’ opinion that to prevent injury to the bull’s nose, the nose lead always should be used in conjunction with a halter. Also, if a bull is being tied to a tie stall or chute, it must never be tied by the nose ring alone.
Anesthesia of the nares Nasal injury repair and application of a nose ring is facilitated by local or regional anesthesia. Minor surgical procedures on the nares are often performed with only mechanical restraint of the head. The bovine nose is innervated by the infraorbital nerve that emerges from the infraorbital foramen. The infraorbital foramen lies just rostral to the facial tuberosity on an imaginary line running from the nasomaxillary notch to the second upper premolar [12]. To perform regional nasal anesthesia the animal’s head must be adequately restrained, and if the animal is uncooperative, acepromazine (0.03 mg/kg, intravenously) or xylazine (0.05 mg/kg, intravenously) may be administered. Twenty to 25 mL of lidocaine is deposited at multiple sites along a vertical line just rostral to the infraorbital foramen and superficial to the maxilla; this procedure needs to be performed on the left and right side.
Nasal laceration Surgical treatment of nasal lacerations is often performed in show or purebred animals or if nasal structures are essential to support a nose ring. Nasolabioplasty should be performed as soon as possible on separated or lacerated nasal tissue to obtain primary healing. The wound should be cleansed, debrided if necessary, and then reapposed using nonabsorbable suture material in a simple interrupted pattern or using a mattress suture pattern. The free parts of the thread may be passed through rubber stents if tension is present. Feeding on the ground should be avoided for 14 days following surgical repair to reduce contamination and disruption of the wound. A nose ring should only be reapplied when healing is sufficient, a minimum of 4 to 6 weeks after repair.
Paranasal sinuses Sinusitis Sinusitis in cattle may be acute or chronic, becoming apparent from 1 week to years after infection. Sinusitis in cattle occurs to various degrees following dehorning, and is often evident in adult animals with openings from the frontal sinus into the horn [13–16]. Cattle dehorned under dusty unsanitary conditions often develop a mild sinusitis. Other causes of frontal sinusitis include formation of bone sequestra subsequent to dehorning, fracture of
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horns, and traumatic fracture of the frontal bone [16]. Other causes of sinusitis include infected tooth roots, extension of actinomycosis or nasal neoplasia into the sinus, sinus cysts and respiratory viruses, and bacteria ascending to the sinuses from the nasal cavity and pharynx. Sinusitis in cattle that occurs after dehorning usually results in pus discharging from the cornual diverticulum of the caudal frontal sinus. These animals are often febrile, anorectic, and appear depressed. Cattle may head press or lower their head and keep their eyes closed, as if in pain. If the dehorning site is closed, clinical signs may include nasal discharge, stridor, and foul breath. Animals with very chronic cases usually show a poor appetite and a decrease in their production parameters. Facial bone swelling and distortion over the affected sinus, exophthalmos because of pus accumulation posterior to the orbit, and neurologic signs also may be observed. In one study of 12 dairy cattle with chronic frontal sinusitis, 4 had an abnormal head posture, with an extended head and neck, closed eyes, and a tendency to head press or to rest their head on a stationary object [16]. The diagnosis of sinusitis can usually be made on the basis of clinical signs. In cases of closed sinusitis or maxillary sinusitis, percussion of the sinus and radiograph are useful diagnostic tools. In the authors’ experience, percussion of the sinus often elicits pain and reveals a dull sound; however, if the sinus is filled with gas because of gas-forming bacteria, hyperresonance may be noted on percussion. Radiographic examination of the head often reveals fluid in the affected sinus. Centesis of the sinus may also be done for collection of diagnostic samples. The area over the affected sinus is prepared for aseptic surgery, and 2% lidocaine hydrochloride is injected subcutaneously. A stab incision is made through the skin down to the surface of the bone. A chuck with a Steinmann pin (5/32 in 4 in length) attached is used to drill through the bone. Polyethylene tubings may be inserted if necessary to aspirate material from the sinus. Material aspirated from the sinus should be examined cytologically and also be cultured for bacterial growth and sensitivity. In one study, Arcanobacter pyogenes was the most common organism isolated from cattle, with chronic frontal sinusitis resulting from dehorning [16]. Pasteurella multocida was the most common bacteria identified from infections of the frontal sinus not associated with dehorning. In the absence of culture and sensitivity results, penicillin or sodium ceftiofur is recommended. Nonsteroidal anti-inflammatory drugs, such as phenylbutazone and flunixin meglumine, are indicated to decrease the inflammation and pain. Long-term therapy is often needed for chronic cases, and facial deformity may be permanent if bony changes were present. Possible complications of chronic frontal sinusitis are intracranial abscesses and septic meningitis. Lethargy, fever, seizures, or blindness also may be observed. In one study, 4 out of 12 dairy cattle with chronic sinusitis had neurologic complications [16]. All four cattle died and had cultures with a large anaerobic component; two of the four had pituitary abscesses. The authors suspected that this resulted from seeding of the pituitary from the
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chronic sinus infection by way of the dural venous sinus system. The erosion or expansion of the sinus boundaries may be directed inward, also causing compression or infection of the central nervous system. To prevent or decrease the frequency of sinusitis, dehorning should be performed at an early age (3 months old). Also, whenever possible, closed methods for dehorning should be used, such as cauterizing techniques in neonates [17]. If dehorning is done in older cattle, it should not be performed if possible during the fly season, or primary skin closure should be done (cosmetic dehorn) [17]. Also, if an open technique is used for dehorning, one should avoid rainy, windy, or dusty conditions. The authors prefer to apply a cotton pad over the wound and apply a topical antiseptic powder to the wound. The cotton pad is held in place by the forming blood clot, and usually remains for 3 to 5 days. Sinusotomy Acute sinusitis is best treated by sinus lavage, parenteral antibiotics, and analgesics. For chronic sinusitis, treatment includes trephination, sinus lavage and drainage, parenteral antibiotics, and analgesics. Trephination sites have been described in cattle, and can be modified as necessary to accommodate bone distortion or wounds from dehorning [13,15,16]. Knowledge of normal skull anatomy prevents inadvertent entry into vital structures. Trephination of the sinus is performed after light sedation and injection of 2% lidocaine hydrochloride over the chosen site. At the chosen site, a 2-cm diameter circular piece of skin is excised and a three quarter–inch sinus trephine (Galt Trephine) is used to create an opening into the sinus. Sinusotomy for the frontal sinus is performed approximately 1-in from the midline, intersecting a line drawn between the caudal aspect of the orbits. If draining tracts or swelling is present at the poll, an additional trephine opening is made in the cornual process of the frontal sinus. If infection is present in the cornual portion of the frontal sinus, devitalized bone and necrotic tissue should be curetted from inside the orifice and any sequestrum removed. If it is necessary to obtain drainage from the postorbital diverticulum, a trephine opening is made 1-in from the posterior edge of the orbital cavity and just dorsal to the temporal canthus. To drain the maxillary sinus an opening is made just dorsal and posterior to the facial tubercle. In young cattle it may be necessary to make the trephine hole 1-in higher to avoid the roots of the maxillary teeth. Sinuses are flushed daily with 1 to 2 L of isotonic saline solution until the infection has resolved (usually 10–21 days). The trephine holes are allowed to close by second intention healing. If the frontomaxillary and ethmoidal meatus is patent, one trephine may be sufficient to provide ventral drainage; however, necrotic debris and distortion of bones may occlude the ethmoidal meatus. In those cases of obstruction of nasal drainage, a 1-cm metal probe may be forcefully passed through the septal plates of the frontal sinus into the nasal meatus for ventral drainage. A roll of gauze or Penrose drain may be used as a stent to keep the opening patent.
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Nasopharynx Mycotic rhinitis and nasal granuloma Nasal granulomas may be caused by fungal infection, Actinobacillus spp, Schistosoma nasalis, foreign bodies, and inhaled allergens [18]. Clinical signs may not be observed in affected cattle, but cattle are most commonly examined because of chronic mucopurulent discharge or epistaxis. Epistaxis is usually unilateral, but bilateral epistaxis may be seen. Fungal organisms cultured from mycotic rhinitis in cattle include Rhinosporidium spp, Helminthosporium spp, Drechslera rostrata, Aspergillus spp, Phycomyces spp, Stachybotrys spp, and Bipolaris spp [19,20]. Nasal granuloma has been reported to have a higher prevalence in regions of higher rainfall, and the incidence of nasal granuloma was related to breed; Jersey and Guernsey cattle had the highest incidence [21]. Treatment of nasal granuloma has a poor success rate; however, in some cattle, mycotic rhinitis may resolve without treatment. Treatment options include surgical resection of the affected tissue (conchae, nasal septum) or administration of sodium iodide (66 mg/kg, intravenously) at weekly intervals for three to four treatments or until iodinism is noted. Surgical treatment is not recommended because the infections are usually diffuse and potentially fatal hemorrhage may occur. Surgical removal of nasal polyps associated with mycotic rhinitis is discussed later. The authors have successfully used transendoscopic application of liquid nitrogen directly to fungal lesions every 10 to 14 days until lesions are no longer observed. Several freeze-thaw cycles are used to achieve sloughing of the infected tissues. Administration of immunostimulants as adjunctive treatment is controversial.
Nasal polyps Nasal or pharyngeal polyps are diagnosed infrequently in cattle. The inciting cause of the formation of nasal polyps is unknown, and may be multifactorial. Mycotic rhinitis may lead to formation of nasal polyps. The most common fungus associated with the formation of nasal polyps is Rhinosporidium spp [22]. Surgical excision may be the treatment of choice, but treatment with sodium iodide and isoniazid also has been reported. Clinical signs are associated with the number, size, and location of the polyps. Increased respiratory noise, nasal discharge, which may be purulent or sanguinous, and variable degrees of dyspnea may be observed. Surgical removal of polyps may be curative. Single polyps may be excised using long instruments (by way of the nares) if the base of the polyp is able to be viewed, or using a transendoscopic wire loop (with or without cautery) or laser with the animal sedated. Multiple polyps or polyps inaccessible by endoscopy may require access through a nasal flap or frontal bone flap, and usually require general anesthesia.
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Conchal cysts Conchal cysts have been most commonly reported to occur in calves 4 to 15 months old [23–26]. Heifers and bulls can be affected. Affected calves had a history of altered breathing or dyspnea beginning soon after birth; however, the authors have diagnosed conchal cysts in adult cattle as incidental findings or as causing minimal nasopharyngeal obstruction. These cysts may have been present for a long period of time without clinical signs because of their small size, or may represent acquired cysts of unknown origin. Cystic conchae may be congenital defects that enlarge slowly until clinical signs of obstruction of the nasopharynx become severe. Conchal cysts may be bilateral or unilateral; clinical signs may include severe respiratory distress with mouth breathing, unilateral nasal obstruction, chronic nasal discharge, head shaking, respiratory noise, and altered conformation of the head. Conchal cysts, however, are most commonly diagnosed during evaluation of cattle with dyspnea. Surgical removal is the treatment of choice for problematic conchal cysts. Unilateral conchal cysts may be removed through the nares with or without the aid of endoscopy or may be removed through a dorsolateral nasal flap. After removal, the affected nasopharynx is packed with rolled cotton gauze for 24 to 72 hours to provide hemostasis. Bilateral conchal cysts may be removed through a dorsal nasal flap and may require partial excision of the nasal septum. Both nasal passages are packed with rolled cotton gauze, and a temporary tracheostomy is maintained until adequate hemostasis is achieved and patency of the nasal passages is restored. Foreign body Nasal foreign bodies are most commonly found in cattle affected by allergic rhinitis. By attempting to scratch pruritic nasal passages, cattle may insert sticks, branches, or other objects into their nares. Cattle also may suffer nasal foreign bodies because of handling accidents or trauma caused by overcrowding. Foreign objects may become embedded in the nasal mucosa and cause the formation of abscesses or granulomas. Treatment includes removal of the foreign material and treatment of secondary infection. Radiography, ultrasonography, and endoscopy are useful to locate the foreign body. Ideally, removal of foreign bodies is done with long surgical instruments or by using transendoscopic instruments; however, a nasal flap is required for retrieval of foreign bodies inaccessible by way of the nares. Cleft palate Cleft palate (palatoschisis) is a severe congenital defect found in calves, but laceration of the soft palate by oral administration of medication is occasionally seen in adult cattle. Cleft palate is most commonly recognized when milk or other ingested feed is seen exiting the nares during or shortly after ingestion; however, some affected calves may be identified during
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evaluation of aspiration pneumonia. Cleft palate may be seen alone, as part of the crooked calf syndrome associated with teratogenic intoxication with lupine plants (Lupinus caudatus, Lupinus sericeus, Lupinus nootkatens is), or as part of the heritable arthrogryposis (autosomal-recessive trait) of Charolais cattle [27]. The authors do not recommend surgical correction of cleft palate without concurrent neutering of affected calves. Cleft palate in calves is usually severe, leaving little tissue for reconstruction of the hard or soft palate; surgical techniques used in foals (mucoperiosteal graft) are of little benefit and invariably fail. The author has performed a vascularized buccal pedicle graft centered on the buccal artery for reconstruction of the hard palate with limited success. Feeding through an indwelling abomasostomy tube was used during healing of the buccal graft. This minimized the risk of trauma to the surgical site and prevented the development of rumen putrefaction, which may be associated with repeated feeding through an esophageal tube. Laceration of soft palate Laceration or perforation of the soft palate most commonly occurs during aggressive use of balling guns or oral speculums for administration of medications. These are more likely when the animal is not adequately restrained or when the administrator is not properly trained in correct methods for the use of these implements. Repair of laceration of the soft palate is best performed with the animal under general anesthesia. An adjustable mouth speculum is used to open the mouth maximally, and long instruments are used to place tension sutures to repair the laceration (cruciate pattern, near-far-far-near pattern, or vertical mattress pattern). Nasolacrimal duct Anomalies of the nasolacrimal duct have been documented in Brown Swiss and Holstein cattle [27,28]. The most common clinical sign is epiphora, but apparent secondary infection has also been seen. Causes of obstruction of the nasolacrimal duct include congenital anomaly, trauma, infection, foreign body, and extramural compression. Conjunctivorhinostomy (creation of a fistula from the conjunctiva into the nasal passage) was performed successfully in a 1-year-old Holstein bull with a suspected congenital anomaly of the right nasolacrimal duct. A trochar was passed from the medial canthus, through the lacrimal bone and ventral nasal concha, and into the ventral nasal meatus. A catheter was passed through this trochar, out of the nares, and tied to itself; the catheter was removed 60 days after surgery. The bull was still clinically normal 17 months after surgery. Heritability of congenital anomalies of the nasolacrimal duct has not been established. Fracture of the skull Fracture of the skull occurs infrequently in cattle. The most commonly diagnosed fractures are of the mandible and of the cornual process of the frontal
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bone. Mandibular fractures causing displacement of the mandible, malocclusion, or dysphagia require treatment. Intramedullary pinning, intraoral acrylic splints, and pinless external fixators provide adequate stabilization of rostral (interdental space) fractures [29,30]. Fractures occurring in the caudal horizontal ramus of the mandible may be treated by application of an external skeletal fixator, pinless external fixator, or compression bone plate [30–33]. Fractures in the vertical ramus of the mandible are treated by application of a compression bone plate. Mandibular fractures that are minimally displaced and are not causing difficulty with mastication do not require surgical treatment. These fractures may be managed by feeding chopped hay or a total mixed ration for 4 to 6 weeks. Fractures of the cornual process of the frontal bone are usually caused by handling injuries to the horns, and are caused by trauma from collision with the head gate of a restraint chute. Open fractures may result in septic osteitis, bone sequestra, or frontal sinusitis. Dehorning at the time of injury is the treatment of choice. When cosmetic healing and preservation of the horns are desired, open reduction and fixation with hemicerclage wires may provide adequate stabilization for healing to occur (3–6 weeks). Malformation of the horn occurs as the horn grows if the germinal tissues have been damaged. Skull fractures causing respiratory obstruction are rare and may be encountered after trailer accidents. The author has observed severe respiratory distress in a l.5-year-old Holstein calf with a skull fracture. The calf had become entrapped in a feed bunk and had struggled for an unknown period of time. Fractures of the frontal and occipital bones were diagnosed at necropsy. Fracture fragments may be removed or reduced and secured with hemicerclage wire. A temporary tracheostomy should be performed when complete obstruction of the nasopharynx is found.
Pharynx and larynx Pharyngeal laceration or trauma Pharyngeal laceration is most commonly associated with balling gun or dosing equipment wounds [34–36]. Occasionally, rough feeds or ingested foreign bodies may cause pharyngeal trauma. Superficial lesions may not cause clinical signs. Sepsis and perilaryngeal abscess result from bacterial inoculation of the soft tissues. Affected cattle are usually observed to have progressive respiratory distress (primarily inspiratory dyspnea) and stand with the head and neck extended. Swelling and perilaryngeal inflammation may result in obstruction of the glottis and death. Cattle also may have malodorous breath, anorexia, swelling in the submandibular region and throat latch, and may stop drinking water. Excessive salivation (ptyalism) may result in fatal electrolyte abnormalities (hyponatremia, hypochloremia, hypokalemia, acidemia). Rumen acidosis may occur from loss of saliva. Forestomach stasis and free-gas bloat may be observed if proximal esophageal obstruction occurs. Fever, dysphagia, and aspiration pneumonia may also be found.
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The author has observed acute hemorrhagic shock and death attributed to necrosis through the internal carotid artery 7 days after pharyngeal laceration and retropharyngeal injection of an oral calcium preparation. Treatment of cattle affected with extensive necrosis (phlegmon) of the perilaryngeal and peripharyngeal tissues may be futile; however, tracheostomy allows return to near-normal breathing while an examination is performed. Transoral digital examination and endoscopy are diagnostic [37]. Radiographs and ultrasonography are helpful to evaluate the extent of the disease and search for foreign bodies (rarely radiopaque) [35]. Transoral treatment of superficial wounds may be performed, followed by administration of antibiotics and anti-inflammatory drugs [38]; however, cattle with severe swelling and infection or with foreign bodies (wire, oral boluses, mineral oil, magnet, and so forth) require surgical exploration of the wound. Retropharyngeal abscesses may be opened and drained directly, but diffuse septic cellulitis should be approached with an incision centered over the ventral larynx [39]. After the skin incision is made, tissues are separated using scissors and digital dissection is continued until the necrotic tissues have been exposed. Limited debridement is done and the wound is left open to allow daily wound care and provide a site for ventral drainage. Digital dissection must be performed with consideration for regional anatomy (jugular veins, carotid arteries, vagosympathetic trunk). Long-term complications of pharyngeal laceration and retropharyngeal cellulitis include laryngeal paralysis or hemiplegia, aspiration of feed, megaesophagus, and dysphagia [40]. Retropharyngeal abscess Retropharyngeal abscesses most commonly are caused by penetrating foreign bodies; traumatic injury to the pharynx (balling guns, dosing syringe, orogastric tube); esophageal rupture (eroded mural ulcer caused by esophageal obstruction); or abscess of the retropharyngeal lymph node (A pyogenes, P multocida, Bordatella bronchiseptica). Respiratory distress is usually the initial complaint, although inappetence, excessive salivation (ptyalism), rumen tympany (bloat), and foul odor are frequently observed. Surgical treatment of retropharyngeal abscess involves incision into the infected tissue [39,41]. This relieves pressure-induced laryngeal collapse and dyspnea and allows time for medical treatment and daily wound care. In severe cases, a temporary tracheostomy may be required. Necrotic pharyngitis and laryngitis (calf diphtheria, laryngeal necrobacillosis) Laryngeal necrobacillosis refers to infection of the larynx and pharynx with Fusobacterium necrophorum. Laryngitis also may be associated with laryngeal ulceration and infection with Pasteurella spp, Haemophilus spp, and Mycoplasma spp [42]. Infection is established when the bacteria gain access to submucosal tissues through abrasions or disruption of the overlying
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mucosae. Infectious bovine rhinotracheitis virus infection should be suspected when extensive laryngotracheitis and pseudomembrane formation is found. Swelling and inflammation result in diminished glottic diameter and cause respiratory distress. Double-muscled calves affected with necrotic laryngitis were found to have increased total pulmonary resistance and decreased dynamic lung compliance and arterial oxygen tension [43]. When laryngeal swelling causes severe limitations of air flow, a temporary tracheostomy allows relatively normal breathing so that medical treatment of the infection can be done. Ideally, antibiotic selection is based on bacterial culture and sensitivity results, but empiric antibiotic therapy may be curative [44]. In one report, cattle having septic laryngitis in which the infection had failed to respond to antibiotics were treated by surgical debridement by laryngotomy [45]. Twenty-three calves and adult cattle were treated surgically by laryngotomy, and this treatment resulted in a 74% success rate. General anesthesia was administered by a tracheal tube placed through a temporary tracheostomy. A ventral midline laryngotomy was made by incising the thyroid, cricoid, and cranial tracheal cartilages. Arytenoid chondritis and laryngeal granuloma Arytenoid chondritis is rarely diagnosed, but is not uncommonly seen in cattle affected with necrotic laryngitis. Arytenoid swelling may cause inspiratory dyspnea and respiratory noise (‘‘honker’’ calves). The narrowed glottis causes increased airway turbulence that may cause the arytenoid swelling to persist. Medical treatment (antibiotics and anti-inflammatory drugs) is usually curative. Administration of steroids is indicated when acute swelling with severe dyspnea is found. The authors have performed temporary tracheostomy in calves when chronic arytenoid swelling caused sufficient inspiratory dyspnea to limit activity and feed intake. Partial or subtotal arytenoidectomy by a laryngotomy is only indicated when necrosis of the arytenoid cartilage is found. Scar tissue formation causing reduced glottic diameter (webbing) may require ventral laryngotomy and surgical reduction of the scar tissue [45]. Excessive scar tissue is usually formed on the vocal cords (vocal process of the arytenoid cartilage); excessive granulation is usually formed on the medial aspect of the arytenoid cartilages. For debridement of the larynx and removal of necrotic cartilage, a ventral midline incision centered over the larynx is made; the sternohyoideus muscles separated; and the thyroid cartilage, cricothyroid ligament, cricoid cartilage, and first two tracheal rings are incised [46]. Volkmann retractors are helpful to expose the larynx. Necrotic tissues are debrided and excised. The laryngotomy may be closed primarily, partially closed with implantation of a Penrose drain, or left open for second-intention healing. A tracheostomy may be required for intubation of the trachea when general anesthesia is used, and the tracheostomy should be maintained after surgery until laryngeal swelling has diminished sufficiently for adequate breathing.
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Laryngeal granuloma may be formed as a result of trauma to the arytenoid cartilage or vocal cords (rough feeds, balling gun, orogastric tube); infection (necrotic laryngitis); infectious bovine rhinotracheitis; laryngeal ulcers [42]; and foreign bodies [47]. Differential diagnoses should include laryngeal abscess, hematoma, neoplasia, and papilloma. When inspiratory dyspnea is present, surgical removal of the granulation tissue is indicated. This may be performed transorally using a wire loop, transendoscopically with cautery or laser, or by a ventral laryngotomy. Endoscopy-guided transoral removal of an extensive laryngeal granuloma was curative in a 5-year-old Hereford bull [47]. A temporary tracheostomy tube was used and aspiration of small quantities of food into the trachea was observed as a short-term complication. Miscellaneous swellings and congenital defects in the throat latch region Focal swelling in the throat latch region is occasionally found in cattle. Often these lesions do not cause clinical signs in the affected animal, but owners desire their removal for cosmetic reasons. Differential diagnoses for focal swellings in the cranial cervical region should include abscess; Actinomyces bovis (lumpy jaw); dermoid cyst; branchial cleft cyst; thyroid hyperplasia; and cutaneous neoplasia. In one report of 14 cattle (13 cows, 1 steer) with thyroid hyperplasia, the affected thyroid was removed with the animal standing and using local anesthesia (nine right side, four left side, one ventral midline) [48]. Bronchial cysts (or brachial cleft cysts) are formed from the embryonic branchial apparatus. These cysts usually occur caudal to the angle of the mandible, but a branchial cleft cyst has been reported in the ventral neck of a 6-month-old Angus bull [49,50]. These lesions rarely cause clinical signs of respiratory problems. Treatment of branchial cysts is done for cosmetic reasons or because of concern that injury to the lesion could result in infection and harm to the animal. The cysts are characterized by nonpainful fluctuant swelling without associated inflammation. Aspiration of the cysts yields a milky fluid that has electrolyte composition similar to serum but is low in protein [49]. Differential diagnoses include dermoid cysts, thyroid hyperplasia, and ectopic structures [48,51,52]. Surgical removal and primary closure are curative and may be done with the animal standing or under general anesthesia. Care must be taken not to damage vital structures underlying the cyst (esophagus, trachea, carotid artery, jugular vein, vagosympathetic trunk). Congenital subepiglottic cyst has been reported in a 14-day-old Brahman heifer causing obstruction of the glottis [53]. The cysts were pedunculated and could be swallowed into the esophagus. This resulted in severe dyspnea, which had been noted since birth. A temporary tracheostomy had been performed when the calf was 2 days old. The cyst was removed transendoscopically with the calf sedated. The origin of these cysts is unknown, but remnants of the thyroglossal duct and branchial clefts have been discussed.
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Surgical access to the nasopharynx Surgical approach to the nasopharynx requires optimal restraint and a thorough understanding of regional anatomy. Iatrogenic injury to vital tissues can result in severe, profuse hemorrhage, trauma to the cranial vault, or obstruction of breathing. Surgery should be performed with the patient under general anesthesia when available and appropriate based on economic concerns. General anesthesia is useful for restraint of fractious animals, allows precise surgical dissection, and minimizes the risk for injury of the patient or to personnel. Access to one side of the nasopharynx is done by making a curved incision centered over the expected site of the lesion. The base of the incision is on the midline of the face and the skin flap is made laterally. Skin is reflected toward the midline, the levator nasolabialis muscle is reflected laterally, and the periosteum is reflected toward the midline to expose the underlying facial bones. The facial vein courses along the lateral aspect of the levator nasolabialis muscle. The infraorbital foramen and infraorbital branch of the maxillary nerve are found ventral to the levator nasolabialis muscle and cranial to the facial vein. A rectangular bone flap is then created by use of an oscillating bone saw or using an osteotome and mallet; the base of the bone flap is toward midline. Before cutting the bone edges, paired holes may be drilled into the facial bone on either side of the caudal and rostral corners of the bone flap to facilitate placement of hemicerclage wires for closure and stabilization of the bone flap after the surgery is completed. The bone flap is reflected medially and the nasopharynx entered. If exposure is inadequate for surgery, the bone flap should be expanded rather than first attempting surgery. When access to both nasal passages is desired, bilateral bone flaps may be made or a central bone flap may be done by centering the incision over the nasal septum and making the base of the bone flap caudally. Surgery in the nasopharynx invariably results in extensive bleeding, interfering with expansion of the bone flap. Close attention must be paid to the extent of hemorrhage. Surgical time is a critical factor. Having a blood donor immediately available is advisable when extensive dissection is expected (nasal septum resection, tumor debulking, and so forth). Submucosal injection of small volumes of epinephrine may considerably attenuate hemorrhage. Application of bovine a-thrombin to the surface of the bleeding tissues (on a gauze pad or soaked into gelfoam) may accelerate coagulation. After surgery has been completed the nasopharynx is packed with roll gauze that is exited through the nares. The gauze roll should be sutured to the nares to ensure that displacement of the gauze does not prevent its retrieval. The bone flap is closed and secured with hemicerclage wire. The periosteum is laid over the bone flap and the muscle and subcutaneous tissues are apposed with #2-0 absorbable suture material (polydioxinone, polyglycolic acid, or chromic gut). The skin is apposed with an interrupted suture pattern (#0 braunamid). The gauze roll is maintained for 24 to 72 hours and then removed. Affected cattle must be closely observed after surgery because
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swallowing of the roll gauze may cause partial obstruction of breathing or eating and may result in aspiration pneumonia. The gauze should be removed with care to prevent reoccurrence of excessive bleeding. Soaking the gauze with saline before removal may reduce the likelihood of disruption of the established blood clot. When bilateral nasal obstruction is anticipated, a temporary tracheostomy should be performed before surgery or before extubation of the patient. This tube is removed when patency of the nasal passages is re-established. Surgery of the larynx and pharynx may be performed transnasally using a flexible endoscope, transorally using a mouth speculum, or by ventral midline pharyngotomy or laryngotomy. Transnasal endoscopy is limited to surgery amenable to transendoscopic instruments (biopsy, wire loops, electrocautery, laser). Manipulation and dissection are minimal. Transoral surgery has limited access to the pharynx and larynx because the mouth can only be opened approximately 30 degrees. Usually surgery is limited to the use of a single hand. Ventral midline pharyngotomy or laryngotomy is the approach of choice when transnasal and transoral approaches are not adequate. Ventral laryngotomy can be performed with the animal standing in a restraint chute. Sedation and use of halters or a nose lead may be required. Tissues are locally anesthetized with 2% lidocaine hydrochloride immediately before surgery. When extensive debridement is anticipated, the authors prefer to perform laryngotomy with the animal under general anesthesia. The authors recommend that all feed and water be withheld from mature cattle for 24 and 12 hours before surgery, respectively, to minimize the risks of regurgitation during surgery. An 8-cm long incision is made along the ventral midline, centered over the thyroid cartilage. The thyroid cartilage of cattle does not have a large V-shaped indentation on its ventral aspect, as is found in horses. Incision through the thyrocricoid ligament provides inadequate exposure to the larynx. Division of the ventral midline of the thyroid, cricoid, and cranial tracheal cartilages may be necessary to achieve adequate exposure [45,46]. Alternatively, the incision may be centered rostral to the thyroid cartilage and a pharyngotomy performed. This involves deeper tissue dissection but provides exposure to the pharynx without incising the laryngeal cartilages. References [1] Callan RI, McGuirk SM, Step DL. Assessment of the cardiovascular and lymphatic systems. Vet Clin North Am Food Anim Pract 1992;8:257–70. [2] Pringle JK. Assessment of the ruminant respiratory system. Vet Clin North Am Food Anim Pract 1992;8:233–42. [3] Pringle JK. Ancillary testing for the ruminant respiratory system. Vet Clin North Am Food Anim Pract 1992;8:243–56. [4] Step DL, McGuirk SM, Callan RJ. Ancillary tests of the cardiovascular and lymphatic systems. Vet Clin North Am Food Anim Pract 1992;8:271–84. [5] Tyler JW, Angel KL, Moll HD, et al. Something old, something new: thoracic acoustic percussion in cattle. J Am Vet Med Assoc 1990;197:52–7.
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[6] Anderson DE, DeBowes RM, Gaughan EM, et al. Endoscopic evaluation of the nasopharynx, pharynx, and larynx of Jersey cows. Am J Vet Res 1994;55:901–4. [7] Anderson DE, Gaughan EM, DeBowes RM, et al. Effects of chemical restraint on the endoscopic appearance of laryngeal and pharyngeal anatomy and sensation in adult cattle. Am J Vet Res 1994;55:1196–200. [8] Braun U, Fohn I, Pusterla N. Ultrasonographic examination of the ventral neck region in cows. Am J Vet Res 1994;55:14–21. [9] Braun U, Sicher D, Pusterla N. Ultrasonography of the lungs, pleura, and mediastinum in healthy cows. Am J Vet Res 1996;57:432–8. [10] Reef VB, Boy MG, Reid CF, et al. Comparison between diagnostic ultrasonography and radiography in the evaluation of horses and cattle with thoracic disease: 56 cases (1984– 1985). J Am Vet Med Assoc 1991;198:2112–8. [11] Kostlin RG, Nuss K, Elma E. Nasolabioplastik nach ausriss des nasenringes beim rind. Tierarztl Prax 1988;16:253–8. [12] Monke DR. Local nasal anesthesia in the bull. Vet Med Small Anim Clin 1981;76:389–93. [13] De La Hunta A, Habel RE. Applied veterinary anatomy. Philadelphia: WB Saunders; 1986. p. 51–3. [14] Nyack B, Padmore CL, Bernard N. Conservative therapy for right frontal sinusitis in a Brahman bull. Vet Med Small Anim Clin 1982;77:107–9. [15] Schneider JE. The respiratory system. In: Oehme FW, editor. Textbook of large animal surgery. 2nd edition. Baltimore: Williams and Wilkins; 1988. p. 356–7. [16] Ward JL, Rebhun WC. Chronic frontal sinusitis in dairy cattle: 12 cases (1978–1989). J Am Vet Med Assoc 1992;201:326–8. [17] Hoffsis G. Surgical (cosmetic) dehorning in cattle. Vet Clin North Am Food Anim Pract 1995;11:159–69. [18] Carbonell PL. Bovine nasal granuloma: a review. Aust Vet J 1976;52:158–65. [19] Penrith ML, Van Der Lugt JJ, Henton MM, et al. A review of mycotic nasal granuloma in cattle, with a report on three cases. J S Afr Vet Assoc 1994;65:179–83. [20] Smith JA, Baker JC. Diseases of the nasal cavity. In: Smith BP, editor. Large animal internal medicine. 2nd edition. St. Louis: Mosby; 1996. p. 620. [21] Hore DE, Thompson WH, Tweddle NE, et al. Nasal granuloma in dairy cattle: distribution in Victoria. Aust Vet J 1973;49:330–4. [22] Prescott J. Systemic mycoses. In: Howard JL, editor. Current veterinary therapy 3: food animal practice. Philadelphia: WB Saunders; 1993. p. 524–9. [23] Cohen ND, Vacek JR, Seahorn TL, et al. Cystic nasal concha in a calf. J Am Vet Med Assoc 1991;198:1035–6. [24] Ross MW, Richardson DW, Hackett RP, et al. Nasal obstruction caused by cystic nasal conchae in cattle. J Am Vet Med Assoc 1986;188:857. [25] St. Jean G, Robertson JT. Cystic nasal concha as a cause of unilateral nasal obstruction in a young bull. Can Vet J 1987;28:251–3. [26] Mundell LD, Smith BP, Hoffman RL, et al. Maxillary sinus cysts in two cattle. J Am Vet Med Assoc 1996;209:127–9. [27] Leipold HW, Hiraga T, Dennis SM. Congenital defects of the bovine musculoskeletal system and joints. Vet Clin North Am 1993;9:93–104. [28] Wilkie DA, Rings DM. Repair of anomalous nasolacrimal duct in a bull by use of conjunctivorhinostomy. J Am Vet Med Assoc 1990;196:1647–50. [29] Colahan PT, Pascoe JR. Stabilization of equine and bovine mandibular and maxillary fractures using an acrylic splint. J Am Vet Med Assoc 1983;182:1117–9. [30] Lischer CJ, Fluri E, Kaser-Hotz B, et al. Pinless external fixation of mandible fractures in cattle. Vet Surg 1997;26:14–9. [31] Alexander SD, Baird AN. Internal fixation of bilateral mandibular body fractures in a steer. J Am Vet Med Assoc 1994;204:420–1. [32] Murch KM. Repair of bovine and equine mandibular fractures. Can Vet J 1980;21:69–73.
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[33] Trent AM, Furguson JB. Bovine mandibular fractures. Can Vet J 1985;26:396–9. [34] Baker JC, Belknap EB, Stickle RL. What is your diagnosis: retropharyngeal abscess and cellulitis associated with a metallic foreign body. J Am Vet Med Assoc 1989;195:382–3. [35] Davidson HP, Rebhun WC, Habel RE. Pharyngeal trauma in cattle. Cornell Vet 1981;71: 15–25. [36] Martig J. Rachenverletzungen beim eingeben von verweilmagneten. Schweiz Arch Tierheilkd 1982;124:209–12. [37] Stober VM, Baackman W. Testing of a new instrument for the inspection of the oropharyngeal cavity and the entrance of the larynx in cattle. Dtsch Tierarztl Wochenschr 1978;85: 189–272. [38] Larson VL. Upper respiratory system. In: Howard JL, editor. Current veterinary therapy: food animal practice 2. Philadelphia: WB Saunders; 1986. p. 654. [39] McClure SR, Crabill MR, Schumacher J, et al. Surgical treatment of retropharyngeal inflammation in two heifers. Vet Med 1994;89:816. [40] Ross CE, Rebhun WC. Megaesophagus in a cow. J Am Vet Med Assoc 1986;188:623–4. [41] Vestweber JG, Roeder B. Medial retropharyngeal lymph node abscess as a cause of respiratory dyspnea in cattle. Compendium on Continuing Education for the Practicing Veterinarian 1986;8:F71. [42] Jensen R, Lauerman LH, Braddy PM, et al. Laryngeal contact ulcers in feedlot cattle. Vet Pathol 1980;17:667–71. [43] Lekeux P, Art T. Functional changes induced by necrotic laryngitis in double muscled calves. Vet Rec 1987;121:353. [44] Plenderleith RWJ. Treatment of cattle, sheep, and horses with lincomycin: case studies. Vet Rec 1988;122:112–3. [45] Fischer W. Experiences with surgical treatment of the larynx in cattle with special consideration of calves. Dtsch Tierarztl Wochenschr 1975;82:137–46. [46] Kersjes AW, Nemeth F, Rutgers LJE. The neck: larynx and trachea. In: Kersjes AW, Nemeth F, Rutgers LJE, editors. Atlas of large animal surgery. Utrecht: Wetenschappelijke uitgeverji Bunge; 1985. p. 23. [47] Gamboa JC, Angel KL, Shoemaker RS, et al. Laryngeal granuloma in a bull. J Am Vet Med Assoc 1992;201:460–2. [48] Cermak VK, Zdelar F, Brkic A. A contribution to the knowledge of pathologic tumors at the larynx and their operational removal in cattle. Dtsch Tierarztl Wochenschr 1979;86:485–90. [49] Misk NA, Ahmed IH, Ismail SF, et al. Branchial cysts in buffalo calves. Agri-Practice 1994; 15:33–5. [50] Smith DF, Gunson DE. Branchial cyst in a heifer. J Am Vet Med Assoc 1977;171:64–6. [51] Baird AN, Wolfe DF, Groth AH. Dermoid cyst in a bull. J Am Vet Med Assoc 1993;202: 298–9. [52] Rieck GW. Akzessorische Kopfanlage (desmiognathus) in der kehlgangsgegend bei einem kalb. Dtsch Tierarztl Wochenschr 1971;78:341–64. [53] Mattoon JS, Andrews D, Jones SL, et al. Subepiglottic cyst causing upper airway obstruction in a neonatal calf. J Am Vet Med Assoc 1991;199:747–9.
Surgery of the Upper Respiratory System David E. Anderson, DVM, MSa,*, Guy St. Jean, DMV, MSb a
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, 1800 Denison Road, Manhattan, KS 66506, USA b Ross University School of Veterinary Medicine, P.O. Box 334, Basseterre, St. Kitts, West Indies
Surgery of the respiratory tract often is considered a last resort. However, these surgeries can be performed successfully, allowing for preservation of genetics and productivity. This article discusses surgery of the upper respiratory system. Aspects of physical, radiographic, endoscopic, and ultrasonographic examination are explored. Conditions of the nares, paranasal sinuses, nasopharynx, palate, nasolacrimal duct, pharynx, and larynx are covered. Physical examination Physical examination of the respiratory system of cattle may be difficult, depending on the nature of the animal [1–4]. Halter-trained cattle are certainly easier to examine than cattle accustomed to the open range. A complete physical examination is critical to thorough work-up of cattle affected with respiratory disease. Determination of the location and severity of the disease is of utmost importance to the surgeon, and helps to narrow the list of differential diagnoses. The character, frequency, and depth of respirations should be noted. The thorax, trachea, larynx, and paranasal sinuses should be ausculted separately to identify the point of maximal intensity of abnormal sounds. The nares should be felt to determine symmetry of air movement and depth of respiration in proportion to the size of the animal. The head should be examined for symmetry and position relative to horizontal. Thoracic auscultation should be performed for all lung fields on both sides of the thorax. Thoracic acoustic percussion can contribute significantly to the information database, particularly when thoracic radiographs and ultrasonography are not available [5]. Acoustic stethoscopes may aid in * Corresponding author. E-mail address: [email protected] (D.E. Anderson). 0749-0720/08/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.cvfa.2008.02.003 vetfood.theclinics.com
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diagnosis of thoracic disease. Hematology and serum biochemistry analysis may be indicated to characterize the nature or severity of a given disease. These tests are chosen after determining economic constraints and when interpretation is believed to be beneficial for guiding therapy or prognosis. Radiographic examination Radiographic examination is indicated when physical examination has isolated the disease to a specific area but cannot sufficiently determine the nature or severity of the disease. Radiographs are useful for evaluation of the skull, trachea, and thorax because the surrounding air density allows detection of soft tissue pathology. Also, lesions may be localized to a specific segment of the respiratory system (eg, sinusitis, retropharyngeal abscess, pulmonary abscess, pericarditis). CT of the thorax has been used by the author to detect disease that is not apparent on radiographs. This technology is limited to calves, small ruminants. or the skulls of adult cattle. Endoscopic examination When possible, chemical restraint should not be used to facilitate endoscopic examination because significant alteration of the endoscopic anatomy may occur [6,7]. A 1-m long endoscope is sufficient to view the nasal passages, pharynx, larynx, proximal trachea, and esophagus of most adult cattle. The accessory bronchus can be viewed in most animals less than 700 kg, but a 3-m endoscope may be necessary for examination of the mainstem bronchi and the full length of the esophagus. The upper airway anatomy of cattle differs from that of horses. The examiner should be familiar with bovine anatomy. Pigmentation of the pharynx and larynx is not uncommon in cattle, and pigmented areas should not be misinterpreted as pathologic tissues [6]. Ultrasonographic examination Ultrasonographic examination of the ventral neck and mediastinum has been described for cattle [8,9]. These examinations may be useful to determine the association of abscesses with vital structures, search for foreign bodies, and determine the extent of lesions before surgery. Interpretation of ultrasonographic images is directly proportional to the examiner’s knowledge of bovine anatomy and experience level. In one study, thoracic ultrasonography was more sensitive than radiographs for detection of small pleural effusion and pulmonary consolidation [10]. Nares Minor surgical procedures and insertion of nose rings are often performed on cattle [11,12]. A nose ring is often applied in cattle that are
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routinely handled, and is helpful during examination of the head, application of tattoos or tags, and minor surgical or medical procedures. It is the authors’ opinion that to prevent injury to the bull’s nose, the nose lead always should be used in conjunction with a halter. Also, if a bull is being tied to a tie stall or chute, it must never be tied by the nose ring alone.
Anesthesia of the nares Nasal injury repair and application of a nose ring is facilitated by local or regional anesthesia. Minor surgical procedures on the nares are often performed with only mechanical restraint of the head. The bovine nose is innervated by the infraorbital nerve that emerges from the infraorbital foramen. The infraorbital foramen lies just rostral to the facial tuberosity on an imaginary line running from the nasomaxillary notch to the second upper premolar [12]. To perform regional nasal anesthesia the animal’s head must be adequately restrained, and if the animal is uncooperative, acepromazine (0.03 mg/kg, intravenously) or xylazine (0.05 mg/kg, intravenously) may be administered. Twenty to 25 mL of lidocaine is deposited at multiple sites along a vertical line just rostral to the infraorbital foramen and superficial to the maxilla; this procedure needs to be performed on the left and right side.
Nasal laceration Surgical treatment of nasal lacerations is often performed in show or purebred animals or if nasal structures are essential to support a nose ring. Nasolabioplasty should be performed as soon as possible on separated or lacerated nasal tissue to obtain primary healing. The wound should be cleansed, debrided if necessary, and then reapposed using nonabsorbable suture material in a simple interrupted pattern or using a mattress suture pattern. The free parts of the thread may be passed through rubber stents if tension is present. Feeding on the ground should be avoided for 14 days following surgical repair to reduce contamination and disruption of the wound. A nose ring should only be reapplied when healing is sufficient, a minimum of 4 to 6 weeks after repair.
Paranasal sinuses Sinusitis Sinusitis in cattle may be acute or chronic, becoming apparent from 1 week to years after infection. Sinusitis in cattle occurs to various degrees following dehorning, and is often evident in adult animals with openings from the frontal sinus into the horn [13–16]. Cattle dehorned under dusty unsanitary conditions often develop a mild sinusitis. Other causes of frontal sinusitis include formation of bone sequestra subsequent to dehorning, fracture of
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horns, and traumatic fracture of the frontal bone [16]. Other causes of sinusitis include infected tooth roots, extension of actinomycosis or nasal neoplasia into the sinus, sinus cysts and respiratory viruses, and bacteria ascending to the sinuses from the nasal cavity and pharynx. Sinusitis in cattle that occurs after dehorning usually results in pus discharging from the cornual diverticulum of the caudal frontal sinus. These animals are often febrile, anorectic, and appear depressed. Cattle may head press or lower their head and keep their eyes closed, as if in pain. If the dehorning site is closed, clinical signs may include nasal discharge, stridor, and foul breath. Animals with very chronic cases usually show a poor appetite and a decrease in their production parameters. Facial bone swelling and distortion over the affected sinus, exophthalmos because of pus accumulation posterior to the orbit, and neurologic signs also may be observed. In one study of 12 dairy cattle with chronic frontal sinusitis, 4 had an abnormal head posture, with an extended head and neck, closed eyes, and a tendency to head press or to rest their head on a stationary object [16]. The diagnosis of sinusitis can usually be made on the basis of clinical signs. In cases of closed sinusitis or maxillary sinusitis, percussion of the sinus and radiograph are useful diagnostic tools. In the authors’ experience, percussion of the sinus often elicits pain and reveals a dull sound; however, if the sinus is filled with gas because of gas-forming bacteria, hyperresonance may be noted on percussion. Radiographic examination of the head often reveals fluid in the affected sinus. Centesis of the sinus may also be done for collection of diagnostic samples. The area over the affected sinus is prepared for aseptic surgery, and 2% lidocaine hydrochloride is injected subcutaneously. A stab incision is made through the skin down to the surface of the bone. A chuck with a Steinmann pin (5/32 in 4 in length) attached is used to drill through the bone. Polyethylene tubings may be inserted if necessary to aspirate material from the sinus. Material aspirated from the sinus should be examined cytologically and also be cultured for bacterial growth and sensitivity. In one study, Arcanobacter pyogenes was the most common organism isolated from cattle, with chronic frontal sinusitis resulting from dehorning [16]. Pasteurella multocida was the most common bacteria identified from infections of the frontal sinus not associated with dehorning. In the absence of culture and sensitivity results, penicillin or sodium ceftiofur is recommended. Nonsteroidal anti-inflammatory drugs, such as phenylbutazone and flunixin meglumine, are indicated to decrease the inflammation and pain. Long-term therapy is often needed for chronic cases, and facial deformity may be permanent if bony changes were present. Possible complications of chronic frontal sinusitis are intracranial abscesses and septic meningitis. Lethargy, fever, seizures, or blindness also may be observed. In one study, 4 out of 12 dairy cattle with chronic sinusitis had neurologic complications [16]. All four cattle died and had cultures with a large anaerobic component; two of the four had pituitary abscesses. The authors suspected that this resulted from seeding of the pituitary from the
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chronic sinus infection by way of the dural venous sinus system. The erosion or expansion of the sinus boundaries may be directed inward, also causing compression or infection of the central nervous system. To prevent or decrease the frequency of sinusitis, dehorning should be performed at an early age (3 months old). Also, whenever possible, closed methods for dehorning should be used, such as cauterizing techniques in neonates [17]. If dehorning is done in older cattle, it should not be performed if possible during the fly season, or primary skin closure should be done (cosmetic dehorn) [17]. Also, if an open technique is used for dehorning, one should avoid rainy, windy, or dusty conditions. The authors prefer to apply a cotton pad over the wound and apply a topical antiseptic powder to the wound. The cotton pad is held in place by the forming blood clot, and usually remains for 3 to 5 days. Sinusotomy Acute sinusitis is best treated by sinus lavage, parenteral antibiotics, and analgesics. For chronic sinusitis, treatment includes trephination, sinus lavage and drainage, parenteral antibiotics, and analgesics. Trephination sites have been described in cattle, and can be modified as necessary to accommodate bone distortion or wounds from dehorning [13,15,16]. Knowledge of normal skull anatomy prevents inadvertent entry into vital structures. Trephination of the sinus is performed after light sedation and injection of 2% lidocaine hydrochloride over the chosen site. At the chosen site, a 2-cm diameter circular piece of skin is excised and a three quarter–inch sinus trephine (Galt Trephine) is used to create an opening into the sinus. Sinusotomy for the frontal sinus is performed approximately 1-in from the midline, intersecting a line drawn between the caudal aspect of the orbits. If draining tracts or swelling is present at the poll, an additional trephine opening is made in the cornual process of the frontal sinus. If infection is present in the cornual portion of the frontal sinus, devitalized bone and necrotic tissue should be curetted from inside the orifice and any sequestrum removed. If it is necessary to obtain drainage from the postorbital diverticulum, a trephine opening is made 1-in from the posterior edge of the orbital cavity and just dorsal to the temporal canthus. To drain the maxillary sinus an opening is made just dorsal and posterior to the facial tubercle. In young cattle it may be necessary to make the trephine hole 1-in higher to avoid the roots of the maxillary teeth. Sinuses are flushed daily with 1 to 2 L of isotonic saline solution until the infection has resolved (usually 10–21 days). The trephine holes are allowed to close by second intention healing. If the frontomaxillary and ethmoidal meatus is patent, one trephine may be sufficient to provide ventral drainage; however, necrotic debris and distortion of bones may occlude the ethmoidal meatus. In those cases of obstruction of nasal drainage, a 1-cm metal probe may be forcefully passed through the septal plates of the frontal sinus into the nasal meatus for ventral drainage. A roll of gauze or Penrose drain may be used as a stent to keep the opening patent.
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Nasopharynx Mycotic rhinitis and nasal granuloma Nasal granulomas may be caused by fungal infection, Actinobacillus spp, Schistosoma nasalis, foreign bodies, and inhaled allergens [18]. Clinical signs may not be observed in affected cattle, but cattle are most commonly examined because of chronic mucopurulent discharge or epistaxis. Epistaxis is usually unilateral, but bilateral epistaxis may be seen. Fungal organisms cultured from mycotic rhinitis in cattle include Rhinosporidium spp, Helminthosporium spp, Drechslera rostrata, Aspergillus spp, Phycomyces spp, Stachybotrys spp, and Bipolaris spp [19,20]. Nasal granuloma has been reported to have a higher prevalence in regions of higher rainfall, and the incidence of nasal granuloma was related to breed; Jersey and Guernsey cattle had the highest incidence [21]. Treatment of nasal granuloma has a poor success rate; however, in some cattle, mycotic rhinitis may resolve without treatment. Treatment options include surgical resection of the affected tissue (conchae, nasal septum) or administration of sodium iodide (66 mg/kg, intravenously) at weekly intervals for three to four treatments or until iodinism is noted. Surgical treatment is not recommended because the infections are usually diffuse and potentially fatal hemorrhage may occur. Surgical removal of nasal polyps associated with mycotic rhinitis is discussed later. The authors have successfully used transendoscopic application of liquid nitrogen directly to fungal lesions every 10 to 14 days until lesions are no longer observed. Several freeze-thaw cycles are used to achieve sloughing of the infected tissues. Administration of immunostimulants as adjunctive treatment is controversial.
Nasal polyps Nasal or pharyngeal polyps are diagnosed infrequently in cattle. The inciting cause of the formation of nasal polyps is unknown, and may be multifactorial. Mycotic rhinitis may lead to formation of nasal polyps. The most common fungus associated with the formation of nasal polyps is Rhinosporidium spp [22]. Surgical excision may be the treatment of choice, but treatment with sodium iodide and isoniazid also has been reported. Clinical signs are associated with the number, size, and location of the polyps. Increased respiratory noise, nasal discharge, which may be purulent or sanguinous, and variable degrees of dyspnea may be observed. Surgical removal of polyps may be curative. Single polyps may be excised using long instruments (by way of the nares) if the base of the polyp is able to be viewed, or using a transendoscopic wire loop (with or without cautery) or laser with the animal sedated. Multiple polyps or polyps inaccessible by endoscopy may require access through a nasal flap or frontal bone flap, and usually require general anesthesia.
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Conchal cysts Conchal cysts have been most commonly reported to occur in calves 4 to 15 months old [23–26]. Heifers and bulls can be affected. Affected calves had a history of altered breathing or dyspnea beginning soon after birth; however, the authors have diagnosed conchal cysts in adult cattle as incidental findings or as causing minimal nasopharyngeal obstruction. These cysts may have been present for a long period of time without clinical signs because of their small size, or may represent acquired cysts of unknown origin. Cystic conchae may be congenital defects that enlarge slowly until clinical signs of obstruction of the nasopharynx become severe. Conchal cysts may be bilateral or unilateral; clinical signs may include severe respiratory distress with mouth breathing, unilateral nasal obstruction, chronic nasal discharge, head shaking, respiratory noise, and altered conformation of the head. Conchal cysts, however, are most commonly diagnosed during evaluation of cattle with dyspnea. Surgical removal is the treatment of choice for problematic conchal cysts. Unilateral conchal cysts may be removed through the nares with or without the aid of endoscopy or may be removed through a dorsolateral nasal flap. After removal, the affected nasopharynx is packed with rolled cotton gauze for 24 to 72 hours to provide hemostasis. Bilateral conchal cysts may be removed through a dorsal nasal flap and may require partial excision of the nasal septum. Both nasal passages are packed with rolled cotton gauze, and a temporary tracheostomy is maintained until adequate hemostasis is achieved and patency of the nasal passages is restored. Foreign body Nasal foreign bodies are most commonly found in cattle affected by allergic rhinitis. By attempting to scratch pruritic nasal passages, cattle may insert sticks, branches, or other objects into their nares. Cattle also may suffer nasal foreign bodies because of handling accidents or trauma caused by overcrowding. Foreign objects may become embedded in the nasal mucosa and cause the formation of abscesses or granulomas. Treatment includes removal of the foreign material and treatment of secondary infection. Radiography, ultrasonography, and endoscopy are useful to locate the foreign body. Ideally, removal of foreign bodies is done with long surgical instruments or by using transendoscopic instruments; however, a nasal flap is required for retrieval of foreign bodies inaccessible by way of the nares. Cleft palate Cleft palate (palatoschisis) is a severe congenital defect found in calves, but laceration of the soft palate by oral administration of medication is occasionally seen in adult cattle. Cleft palate is most commonly recognized when milk or other ingested feed is seen exiting the nares during or shortly after ingestion; however, some affected calves may be identified during
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evaluation of aspiration pneumonia. Cleft palate may be seen alone, as part of the crooked calf syndrome associated with teratogenic intoxication with lupine plants (Lupinus caudatus, Lupinus sericeus, Lupinus nootkatens is), or as part of the heritable arthrogryposis (autosomal-recessive trait) of Charolais cattle [27]. The authors do not recommend surgical correction of cleft palate without concurrent neutering of affected calves. Cleft palate in calves is usually severe, leaving little tissue for reconstruction of the hard or soft palate; surgical techniques used in foals (mucoperiosteal graft) are of little benefit and invariably fail. The author has performed a vascularized buccal pedicle graft centered on the buccal artery for reconstruction of the hard palate with limited success. Feeding through an indwelling abomasostomy tube was used during healing of the buccal graft. This minimized the risk of trauma to the surgical site and prevented the development of rumen putrefaction, which may be associated with repeated feeding through an esophageal tube. Laceration of soft palate Laceration or perforation of the soft palate most commonly occurs during aggressive use of balling guns or oral speculums for administration of medications. These are more likely when the animal is not adequately restrained or when the administrator is not properly trained in correct methods for the use of these implements. Repair of laceration of the soft palate is best performed with the animal under general anesthesia. An adjustable mouth speculum is used to open the mouth maximally, and long instruments are used to place tension sutures to repair the laceration (cruciate pattern, near-far-far-near pattern, or vertical mattress pattern). Nasolacrimal duct Anomalies of the nasolacrimal duct have been documented in Brown Swiss and Holstein cattle [27,28]. The most common clinical sign is epiphora, but apparent secondary infection has also been seen. Causes of obstruction of the nasolacrimal duct include congenital anomaly, trauma, infection, foreign body, and extramural compression. Conjunctivorhinostomy (creation of a fistula from the conjunctiva into the nasal passage) was performed successfully in a 1-year-old Holstein bull with a suspected congenital anomaly of the right nasolacrimal duct. A trochar was passed from the medial canthus, through the lacrimal bone and ventral nasal concha, and into the ventral nasal meatus. A catheter was passed through this trochar, out of the nares, and tied to itself; the catheter was removed 60 days after surgery. The bull was still clinically normal 17 months after surgery. Heritability of congenital anomalies of the nasolacrimal duct has not been established. Fracture of the skull Fracture of the skull occurs infrequently in cattle. The most commonly diagnosed fractures are of the mandible and of the cornual process of the frontal
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bone. Mandibular fractures causing displacement of the mandible, malocclusion, or dysphagia require treatment. Intramedullary pinning, intraoral acrylic splints, and pinless external fixators provide adequate stabilization of rostral (interdental space) fractures [29,30]. Fractures occurring in the caudal horizontal ramus of the mandible may be treated by application of an external skeletal fixator, pinless external fixator, or compression bone plate [30–33]. Fractures in the vertical ramus of the mandible are treated by application of a compression bone plate. Mandibular fractures that are minimally displaced and are not causing difficulty with mastication do not require surgical treatment. These fractures may be managed by feeding chopped hay or a total mixed ration for 4 to 6 weeks. Fractures of the cornual process of the frontal bone are usually caused by handling injuries to the horns, and are caused by trauma from collision with the head gate of a restraint chute. Open fractures may result in septic osteitis, bone sequestra, or frontal sinusitis. Dehorning at the time of injury is the treatment of choice. When cosmetic healing and preservation of the horns are desired, open reduction and fixation with hemicerclage wires may provide adequate stabilization for healing to occur (3–6 weeks). Malformation of the horn occurs as the horn grows if the germinal tissues have been damaged. Skull fractures causing respiratory obstruction are rare and may be encountered after trailer accidents. The author has observed severe respiratory distress in a l.5-year-old Holstein calf with a skull fracture. The calf had become entrapped in a feed bunk and had struggled for an unknown period of time. Fractures of the frontal and occipital bones were diagnosed at necropsy. Fracture fragments may be removed or reduced and secured with hemicerclage wire. A temporary tracheostomy should be performed when complete obstruction of the nasopharynx is found.
Pharynx and larynx Pharyngeal laceration or trauma Pharyngeal laceration is most commonly associated with balling gun or dosing equipment wounds [34–36]. Occasionally, rough feeds or ingested foreign bodies may cause pharyngeal trauma. Superficial lesions may not cause clinical signs. Sepsis and perilaryngeal abscess result from bacterial inoculation of the soft tissues. Affected cattle are usually observed to have progressive respiratory distress (primarily inspiratory dyspnea) and stand with the head and neck extended. Swelling and perilaryngeal inflammation may result in obstruction of the glottis and death. Cattle also may have malodorous breath, anorexia, swelling in the submandibular region and throat latch, and may stop drinking water. Excessive salivation (ptyalism) may result in fatal electrolyte abnormalities (hyponatremia, hypochloremia, hypokalemia, acidemia). Rumen acidosis may occur from loss of saliva. Forestomach stasis and free-gas bloat may be observed if proximal esophageal obstruction occurs. Fever, dysphagia, and aspiration pneumonia may also be found.
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The author has observed acute hemorrhagic shock and death attributed to necrosis through the internal carotid artery 7 days after pharyngeal laceration and retropharyngeal injection of an oral calcium preparation. Treatment of cattle affected with extensive necrosis (phlegmon) of the perilaryngeal and peripharyngeal tissues may be futile; however, tracheostomy allows return to near-normal breathing while an examination is performed. Transoral digital examination and endoscopy are diagnostic [37]. Radiographs and ultrasonography are helpful to evaluate the extent of the disease and search for foreign bodies (rarely radiopaque) [35]. Transoral treatment of superficial wounds may be performed, followed by administration of antibiotics and anti-inflammatory drugs [38]; however, cattle with severe swelling and infection or with foreign bodies (wire, oral boluses, mineral oil, magnet, and so forth) require surgical exploration of the wound. Retropharyngeal abscesses may be opened and drained directly, but diffuse septic cellulitis should be approached with an incision centered over the ventral larynx [39]. After the skin incision is made, tissues are separated using scissors and digital dissection is continued until the necrotic tissues have been exposed. Limited debridement is done and the wound is left open to allow daily wound care and provide a site for ventral drainage. Digital dissection must be performed with consideration for regional anatomy (jugular veins, carotid arteries, vagosympathetic trunk). Long-term complications of pharyngeal laceration and retropharyngeal cellulitis include laryngeal paralysis or hemiplegia, aspiration of feed, megaesophagus, and dysphagia [40]. Retropharyngeal abscess Retropharyngeal abscesses most commonly are caused by penetrating foreign bodies; traumatic injury to the pharynx (balling guns, dosing syringe, orogastric tube); esophageal rupture (eroded mural ulcer caused by esophageal obstruction); or abscess of the retropharyngeal lymph node (A pyogenes, P multocida, Bordatella bronchiseptica). Respiratory distress is usually the initial complaint, although inappetence, excessive salivation (ptyalism), rumen tympany (bloat), and foul odor are frequently observed. Surgical treatment of retropharyngeal abscess involves incision into the infected tissue [39,41]. This relieves pressure-induced laryngeal collapse and dyspnea and allows time for medical treatment and daily wound care. In severe cases, a temporary tracheostomy may be required. Necrotic pharyngitis and laryngitis (calf diphtheria, laryngeal necrobacillosis) Laryngeal necrobacillosis refers to infection of the larynx and pharynx with Fusobacterium necrophorum. Laryngitis also may be associated with laryngeal ulceration and infection with Pasteurella spp, Haemophilus spp, and Mycoplasma spp [42]. Infection is established when the bacteria gain access to submucosal tissues through abrasions or disruption of the overlying
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mucosae. Infectious bovine rhinotracheitis virus infection should be suspected when extensive laryngotracheitis and pseudomembrane formation is found. Swelling and inflammation result in diminished glottic diameter and cause respiratory distress. Double-muscled calves affected with necrotic laryngitis were found to have increased total pulmonary resistance and decreased dynamic lung compliance and arterial oxygen tension [43]. When laryngeal swelling causes severe limitations of air flow, a temporary tracheostomy allows relatively normal breathing so that medical treatment of the infection can be done. Ideally, antibiotic selection is based on bacterial culture and sensitivity results, but empiric antibiotic therapy may be curative [44]. In one report, cattle having septic laryngitis in which the infection had failed to respond to antibiotics were treated by surgical debridement by laryngotomy [45]. Twenty-three calves and adult cattle were treated surgically by laryngotomy, and this treatment resulted in a 74% success rate. General anesthesia was administered by a tracheal tube placed through a temporary tracheostomy. A ventral midline laryngotomy was made by incising the thyroid, cricoid, and cranial tracheal cartilages. Arytenoid chondritis and laryngeal granuloma Arytenoid chondritis is rarely diagnosed, but is not uncommonly seen in cattle affected with necrotic laryngitis. Arytenoid swelling may cause inspiratory dyspnea and respiratory noise (‘‘honker’’ calves). The narrowed glottis causes increased airway turbulence that may cause the arytenoid swelling to persist. Medical treatment (antibiotics and anti-inflammatory drugs) is usually curative. Administration of steroids is indicated when acute swelling with severe dyspnea is found. The authors have performed temporary tracheostomy in calves when chronic arytenoid swelling caused sufficient inspiratory dyspnea to limit activity and feed intake. Partial or subtotal arytenoidectomy by a laryngotomy is only indicated when necrosis of the arytenoid cartilage is found. Scar tissue formation causing reduced glottic diameter (webbing) may require ventral laryngotomy and surgical reduction of the scar tissue [45]. Excessive scar tissue is usually formed on the vocal cords (vocal process of the arytenoid cartilage); excessive granulation is usually formed on the medial aspect of the arytenoid cartilages. For debridement of the larynx and removal of necrotic cartilage, a ventral midline incision centered over the larynx is made; the sternohyoideus muscles separated; and the thyroid cartilage, cricothyroid ligament, cricoid cartilage, and first two tracheal rings are incised [46]. Volkmann retractors are helpful to expose the larynx. Necrotic tissues are debrided and excised. The laryngotomy may be closed primarily, partially closed with implantation of a Penrose drain, or left open for second-intention healing. A tracheostomy may be required for intubation of the trachea when general anesthesia is used, and the tracheostomy should be maintained after surgery until laryngeal swelling has diminished sufficiently for adequate breathing.
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Laryngeal granuloma may be formed as a result of trauma to the arytenoid cartilage or vocal cords (rough feeds, balling gun, orogastric tube); infection (necrotic laryngitis); infectious bovine rhinotracheitis; laryngeal ulcers [42]; and foreign bodies [47]. Differential diagnoses should include laryngeal abscess, hematoma, neoplasia, and papilloma. When inspiratory dyspnea is present, surgical removal of the granulation tissue is indicated. This may be performed transorally using a wire loop, transendoscopically with cautery or laser, or by a ventral laryngotomy. Endoscopy-guided transoral removal of an extensive laryngeal granuloma was curative in a 5-year-old Hereford bull [47]. A temporary tracheostomy tube was used and aspiration of small quantities of food into the trachea was observed as a short-term complication. Miscellaneous swellings and congenital defects in the throat latch region Focal swelling in the throat latch region is occasionally found in cattle. Often these lesions do not cause clinical signs in the affected animal, but owners desire their removal for cosmetic reasons. Differential diagnoses for focal swellings in the cranial cervical region should include abscess; Actinomyces bovis (lumpy jaw); dermoid cyst; branchial cleft cyst; thyroid hyperplasia; and cutaneous neoplasia. In one report of 14 cattle (13 cows, 1 steer) with thyroid hyperplasia, the affected thyroid was removed with the animal standing and using local anesthesia (nine right side, four left side, one ventral midline) [48]. Bronchial cysts (or brachial cleft cysts) are formed from the embryonic branchial apparatus. These cysts usually occur caudal to the angle of the mandible, but a branchial cleft cyst has been reported in the ventral neck of a 6-month-old Angus bull [49,50]. These lesions rarely cause clinical signs of respiratory problems. Treatment of branchial cysts is done for cosmetic reasons or because of concern that injury to the lesion could result in infection and harm to the animal. The cysts are characterized by nonpainful fluctuant swelling without associated inflammation. Aspiration of the cysts yields a milky fluid that has electrolyte composition similar to serum but is low in protein [49]. Differential diagnoses include dermoid cysts, thyroid hyperplasia, and ectopic structures [48,51,52]. Surgical removal and primary closure are curative and may be done with the animal standing or under general anesthesia. Care must be taken not to damage vital structures underlying the cyst (esophagus, trachea, carotid artery, jugular vein, vagosympathetic trunk). Congenital subepiglottic cyst has been reported in a 14-day-old Brahman heifer causing obstruction of the glottis [53]. The cysts were pedunculated and could be swallowed into the esophagus. This resulted in severe dyspnea, which had been noted since birth. A temporary tracheostomy had been performed when the calf was 2 days old. The cyst was removed transendoscopically with the calf sedated. The origin of these cysts is unknown, but remnants of the thyroglossal duct and branchial clefts have been discussed.
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Surgical access to the nasopharynx Surgical approach to the nasopharynx requires optimal restraint and a thorough understanding of regional anatomy. Iatrogenic injury to vital tissues can result in severe, profuse hemorrhage, trauma to the cranial vault, or obstruction of breathing. Surgery should be performed with the patient under general anesthesia when available and appropriate based on economic concerns. General anesthesia is useful for restraint of fractious animals, allows precise surgical dissection, and minimizes the risk for injury of the patient or to personnel. Access to one side of the nasopharynx is done by making a curved incision centered over the expected site of the lesion. The base of the incision is on the midline of the face and the skin flap is made laterally. Skin is reflected toward the midline, the levator nasolabialis muscle is reflected laterally, and the periosteum is reflected toward the midline to expose the underlying facial bones. The facial vein courses along the lateral aspect of the levator nasolabialis muscle. The infraorbital foramen and infraorbital branch of the maxillary nerve are found ventral to the levator nasolabialis muscle and cranial to the facial vein. A rectangular bone flap is then created by use of an oscillating bone saw or using an osteotome and mallet; the base of the bone flap is toward midline. Before cutting the bone edges, paired holes may be drilled into the facial bone on either side of the caudal and rostral corners of the bone flap to facilitate placement of hemicerclage wires for closure and stabilization of the bone flap after the surgery is completed. The bone flap is reflected medially and the nasopharynx entered. If exposure is inadequate for surgery, the bone flap should be expanded rather than first attempting surgery. When access to both nasal passages is desired, bilateral bone flaps may be made or a central bone flap may be done by centering the incision over the nasal septum and making the base of the bone flap caudally. Surgery in the nasopharynx invariably results in extensive bleeding, interfering with expansion of the bone flap. Close attention must be paid to the extent of hemorrhage. Surgical time is a critical factor. Having a blood donor immediately available is advisable when extensive dissection is expected (nasal septum resection, tumor debulking, and so forth). Submucosal injection of small volumes of epinephrine may considerably attenuate hemorrhage. Application of bovine a-thrombin to the surface of the bleeding tissues (on a gauze pad or soaked into gelfoam) may accelerate coagulation. After surgery has been completed the nasopharynx is packed with roll gauze that is exited through the nares. The gauze roll should be sutured to the nares to ensure that displacement of the gauze does not prevent its retrieval. The bone flap is closed and secured with hemicerclage wire. The periosteum is laid over the bone flap and the muscle and subcutaneous tissues are apposed with #2-0 absorbable suture material (polydioxinone, polyglycolic acid, or chromic gut). The skin is apposed with an interrupted suture pattern (#0 braunamid). The gauze roll is maintained for 24 to 72 hours and then removed. Affected cattle must be closely observed after surgery because
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swallowing of the roll gauze may cause partial obstruction of breathing or eating and may result in aspiration pneumonia. The gauze should be removed with care to prevent reoccurrence of excessive bleeding. Soaking the gauze with saline before removal may reduce the likelihood of disruption of the established blood clot. When bilateral nasal obstruction is anticipated, a temporary tracheostomy should be performed before surgery or before extubation of the patient. This tube is removed when patency of the nasal passages is re-established. Surgery of the larynx and pharynx may be performed transnasally using a flexible endoscope, transorally using a mouth speculum, or by ventral midline pharyngotomy or laryngotomy. Transnasal endoscopy is limited to surgery amenable to transendoscopic instruments (biopsy, wire loops, electrocautery, laser). Manipulation and dissection are minimal. Transoral surgery has limited access to the pharynx and larynx because the mouth can only be opened approximately 30 degrees. Usually surgery is limited to the use of a single hand. Ventral midline pharyngotomy or laryngotomy is the approach of choice when transnasal and transoral approaches are not adequate. Ventral laryngotomy can be performed with the animal standing in a restraint chute. Sedation and use of halters or a nose lead may be required. Tissues are locally anesthetized with 2% lidocaine hydrochloride immediately before surgery. When extensive debridement is anticipated, the authors prefer to perform laryngotomy with the animal under general anesthesia. The authors recommend that all feed and water be withheld from mature cattle for 24 and 12 hours before surgery, respectively, to minimize the risks of regurgitation during surgery. An 8-cm long incision is made along the ventral midline, centered over the thyroid cartilage. The thyroid cartilage of cattle does not have a large V-shaped indentation on its ventral aspect, as is found in horses. Incision through the thyrocricoid ligament provides inadequate exposure to the larynx. Division of the ventral midline of the thyroid, cricoid, and cranial tracheal cartilages may be necessary to achieve adequate exposure [45,46]. Alternatively, the incision may be centered rostral to the thyroid cartilage and a pharyngotomy performed. This involves deeper tissue dissection but provides exposure to the pharynx without incising the laryngeal cartilages. References [1] Callan RI, McGuirk SM, Step DL. Assessment of the cardiovascular and lymphatic systems. Vet Clin North Am Food Anim Pract 1992;8:257–70. [2] Pringle JK. Assessment of the ruminant respiratory system. Vet Clin North Am Food Anim Pract 1992;8:233–42. [3] Pringle JK. Ancillary testing for the ruminant respiratory system. Vet Clin North Am Food Anim Pract 1992;8:243–56. [4] Step DL, McGuirk SM, Callan RJ. Ancillary tests of the cardiovascular and lymphatic systems. Vet Clin North Am Food Anim Pract 1992;8:271–84. [5] Tyler JW, Angel KL, Moll HD, et al. Something old, something new: thoracic acoustic percussion in cattle. J Am Vet Med Assoc 1990;197:52–7.
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[6] Anderson DE, DeBowes RM, Gaughan EM, et al. Endoscopic evaluation of the nasopharynx, pharynx, and larynx of Jersey cows. Am J Vet Res 1994;55:901–4. [7] Anderson DE, Gaughan EM, DeBowes RM, et al. Effects of chemical restraint on the endoscopic appearance of laryngeal and pharyngeal anatomy and sensation in adult cattle. Am J Vet Res 1994;55:1196–200. [8] Braun U, Fohn I, Pusterla N. Ultrasonographic examination of the ventral neck region in cows. Am J Vet Res 1994;55:14–21. [9] Braun U, Sicher D, Pusterla N. Ultrasonography of the lungs, pleura, and mediastinum in healthy cows. Am J Vet Res 1996;57:432–8. [10] Reef VB, Boy MG, Reid CF, et al. Comparison between diagnostic ultrasonography and radiography in the evaluation of horses and cattle with thoracic disease: 56 cases (1984– 1985). J Am Vet Med Assoc 1991;198:2112–8. [11] Kostlin RG, Nuss K, Elma E. Nasolabioplastik nach ausriss des nasenringes beim rind. Tierarztl Prax 1988;16:253–8. [12] Monke DR. Local nasal anesthesia in the bull. Vet Med Small Anim Clin 1981;76:389–93. [13] De La Hunta A, Habel RE. Applied veterinary anatomy. Philadelphia: WB Saunders; 1986. p. 51–3. [14] Nyack B, Padmore CL, Bernard N. Conservative therapy for right frontal sinusitis in a Brahman bull. Vet Med Small Anim Clin 1982;77:107–9. [15] Schneider JE. The respiratory system. In: Oehme FW, editor. Textbook of large animal surgery. 2nd edition. Baltimore: Williams and Wilkins; 1988. p. 356–7. [16] Ward JL, Rebhun WC. Chronic frontal sinusitis in dairy cattle: 12 cases (1978–1989). J Am Vet Med Assoc 1992;201:326–8. [17] Hoffsis G. Surgical (cosmetic) dehorning in cattle. Vet Clin North Am Food Anim Pract 1995;11:159–69. [18] Carbonell PL. Bovine nasal granuloma: a review. Aust Vet J 1976;52:158–65. [19] Penrith ML, Van Der Lugt JJ, Henton MM, et al. A review of mycotic nasal granuloma in cattle, with a report on three cases. J S Afr Vet Assoc 1994;65:179–83. [20] Smith JA, Baker JC. Diseases of the nasal cavity. In: Smith BP, editor. Large animal internal medicine. 2nd edition. St. Louis: Mosby; 1996. p. 620. [21] Hore DE, Thompson WH, Tweddle NE, et al. Nasal granuloma in dairy cattle: distribution in Victoria. Aust Vet J 1973;49:330–4. [22] Prescott J. Systemic mycoses. In: Howard JL, editor. Current veterinary therapy 3: food animal practice. Philadelphia: WB Saunders; 1993. p. 524–9. [23] Cohen ND, Vacek JR, Seahorn TL, et al. Cystic nasal concha in a calf. J Am Vet Med Assoc 1991;198:1035–6. [24] Ross MW, Richardson DW, Hackett RP, et al. Nasal obstruction caused by cystic nasal conchae in cattle. J Am Vet Med Assoc 1986;188:857. [25] St. Jean G, Robertson JT. Cystic nasal concha as a cause of unilateral nasal obstruction in a young bull. Can Vet J 1987;28:251–3. [26] Mundell LD, Smith BP, Hoffman RL, et al. Maxillary sinus cysts in two cattle. J Am Vet Med Assoc 1996;209:127–9. [27] Leipold HW, Hiraga T, Dennis SM. Congenital defects of the bovine musculoskeletal system and joints. Vet Clin North Am 1993;9:93–104. [28] Wilkie DA, Rings DM. Repair of anomalous nasolacrimal duct in a bull by use of conjunctivorhinostomy. J Am Vet Med Assoc 1990;196:1647–50. [29] Colahan PT, Pascoe JR. Stabilization of equine and bovine mandibular and maxillary fractures using an acrylic splint. J Am Vet Med Assoc 1983;182:1117–9. [30] Lischer CJ, Fluri E, Kaser-Hotz B, et al. Pinless external fixation of mandible fractures in cattle. Vet Surg 1997;26:14–9. [31] Alexander SD, Baird AN. Internal fixation of bilateral mandibular body fractures in a steer. J Am Vet Med Assoc 1994;204:420–1. [32] Murch KM. Repair of bovine and equine mandibular fractures. Can Vet J 1980;21:69–73.
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[33] Trent AM, Furguson JB. Bovine mandibular fractures. Can Vet J 1985;26:396–9. [34] Baker JC, Belknap EB, Stickle RL. What is your diagnosis: retropharyngeal abscess and cellulitis associated with a metallic foreign body. J Am Vet Med Assoc 1989;195:382–3. [35] Davidson HP, Rebhun WC, Habel RE. Pharyngeal trauma in cattle. Cornell Vet 1981;71: 15–25. [36] Martig J. Rachenverletzungen beim eingeben von verweilmagneten. Schweiz Arch Tierheilkd 1982;124:209–12. [37] Stober VM, Baackman W. Testing of a new instrument for the inspection of the oropharyngeal cavity and the entrance of the larynx in cattle. Dtsch Tierarztl Wochenschr 1978;85: 189–272. [38] Larson VL. Upper respiratory system. In: Howard JL, editor. Current veterinary therapy: food animal practice 2. Philadelphia: WB Saunders; 1986. p. 654. [39] McClure SR, Crabill MR, Schumacher J, et al. Surgical treatment of retropharyngeal inflammation in two heifers. Vet Med 1994;89:816. [40] Ross CE, Rebhun WC. Megaesophagus in a cow. J Am Vet Med Assoc 1986;188:623–4. [41] Vestweber JG, Roeder B. Medial retropharyngeal lymph node abscess as a cause of respiratory dyspnea in cattle. Compendium on Continuing Education for the Practicing Veterinarian 1986;8:F71. [42] Jensen R, Lauerman LH, Braddy PM, et al. Laryngeal contact ulcers in feedlot cattle. Vet Pathol 1980;17:667–71. [43] Lekeux P, Art T. Functional changes induced by necrotic laryngitis in double muscled calves. Vet Rec 1987;121:353. [44] Plenderleith RWJ. Treatment of cattle, sheep, and horses with lincomycin: case studies. Vet Rec 1988;122:112–3. [45] Fischer W. Experiences with surgical treatment of the larynx in cattle with special consideration of calves. Dtsch Tierarztl Wochenschr 1975;82:137–46. [46] Kersjes AW, Nemeth F, Rutgers LJE. The neck: larynx and trachea. In: Kersjes AW, Nemeth F, Rutgers LJE, editors. Atlas of large animal surgery. Utrecht: Wetenschappelijke uitgeverji Bunge; 1985. p. 23. [47] Gamboa JC, Angel KL, Shoemaker RS, et al. Laryngeal granuloma in a bull. J Am Vet Med Assoc 1992;201:460–2. [48] Cermak VK, Zdelar F, Brkic A. A contribution to the knowledge of pathologic tumors at the larynx and their operational removal in cattle. Dtsch Tierarztl Wochenschr 1979;86:485–90. [49] Misk NA, Ahmed IH, Ismail SF, et al. Branchial cysts in buffalo calves. Agri-Practice 1994; 15:33–5. [50] Smith DF, Gunson DE. Branchial cyst in a heifer. J Am Vet Med Assoc 1977;171:64–6. [51] Baird AN, Wolfe DF, Groth AH. Dermoid cyst in a bull. J Am Vet Med Assoc 1993;202: 298–9. [52] Rieck GW. Akzessorische Kopfanlage (desmiognathus) in der kehlgangsgegend bei einem kalb. Dtsch Tierarztl Wochenschr 1971;78:341–64. [53] Mattoon JS, Andrews D, Jones SL, et al. Subepiglottic cyst causing upper airway obstruction in a neonatal calf. J Am Vet Med Assoc 1991;199:747–9.