Treatment of intrathoracic grass awn migration with video-assisted thoracic surgery in two dogs

Shelly Shamir Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Philipp D. Mayhew Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Allison Zwingenberger Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Lynelle R. Johnson Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Abstract

CASE DESCRIPTION A 17-month-old sexually intact male Vizsla and a 2-year-old spayed female mixed-breed dog were examined because of suspected intrathoracic grass awn migration.

CLINICAL FINDINGS Thoracic CT revealed focal areas of pulmonary infiltration in the right caudal lung lobe in one dog and in the left caudal lung lobe in the other. In 1 patient, bronchoscopy revealed 2 grass awns in the bronchi. Results of thoracic radiography and bronchoscopy were unremarkable in the second patient; however, a grass awn was recovered from the tonsillar crypt during oropharyngeal examination.

TREATMENT AND OUTCOME In both dogs, grass awns were successfully retrieved from the pleural cavity by means of video-assisted thoracic surgery during 1-lung ventilation. In one patient, a grass awn was recovered bronchoscopically from the left caudal lung lobe bronchus and another was visualized distally in an accessory lung lobe bronchus but could not be retrieved. This dog underwent accessory lung lobectomy. The second dog underwent left caudal lung lobectomy. Both patients recovered uneventfully from surgery, were discharged from the hospital, and had no apparent recurrence of clinical signs at telephone follow-up 31 months and 18 months after surgery.

CLINICAL RELEVANCE With careful case selection, successful management of intrathoracic grass awn migration in dogs can be achieved by means of video-assisted thoracic surgery. Comprehensive preoperative evaluation including both computed tomography and bronchoscopy is suggested. Further investigation is necessary to evaluate whether treatment of this condition with video-assisted thoracic surgery is as effective as with traditional open thoracotomy.

Abstract

CASE DESCRIPTION A 17-month-old sexually intact male Vizsla and a 2-year-old spayed female mixed-breed dog were examined because of suspected intrathoracic grass awn migration.

CLINICAL FINDINGS Thoracic CT revealed focal areas of pulmonary infiltration in the right caudal lung lobe in one dog and in the left caudal lung lobe in the other. In 1 patient, bronchoscopy revealed 2 grass awns in the bronchi. Results of thoracic radiography and bronchoscopy were unremarkable in the second patient; however, a grass awn was recovered from the tonsillar crypt during oropharyngeal examination.

TREATMENT AND OUTCOME In both dogs, grass awns were successfully retrieved from the pleural cavity by means of video-assisted thoracic surgery during 1-lung ventilation. In one patient, a grass awn was recovered bronchoscopically from the left caudal lung lobe bronchus and another was visualized distally in an accessory lung lobe bronchus but could not be retrieved. This dog underwent accessory lung lobectomy. The second dog underwent left caudal lung lobectomy. Both patients recovered uneventfully from surgery, were discharged from the hospital, and had no apparent recurrence of clinical signs at telephone follow-up 31 months and 18 months after surgery.

CLINICAL RELEVANCE With careful case selection, successful management of intrathoracic grass awn migration in dogs can be achieved by means of video-assisted thoracic surgery. Comprehensive preoperative evaluation including both computed tomography and bronchoscopy is suggested. Further investigation is necessary to evaluate whether treatment of this condition with video-assisted thoracic surgery is as effective as with traditional open thoracotomy.

A17-month-old 26-kg (57-lb) sexually intact male Vizsla (dog 1) was examined because of a 1-day history of lethargy and inappetence following a weekend hunting trip. The dog had been evaluated at an emergency clinic where it was found to be clinically dehydrated (5%) and febrile (39.7°C [103.5°F]). Intravenous fluid therapy was administered, and treatment with enrofloxacin (15 mg/kg [6.8 mg/lb], PO, q 24 h) and ampicillin-sulbactam (22 mg/kg [10 mg/lb], IV, q8h) was initiated. Thoracic radiography revealed pleural fissure lines and mild interstitial infiltrates in the right caudal lung lobe suggestive of pleuropneumonia, and the owners elected to pursue referral and further evaluation at the University of California-Davis William R. Pritchard Veterinary Medical Teaching Hospital. On arrival, physical examination revealed a temperature of 38.3°C (101°F), pulse rate of 88 beats/min, and respiratory rate of 24 breaths/min. Clear breath sounds were evident on auscultation of all lung fields. Results of a CBC revealed an Hct within reference limits (0.42 L/L; reference interval, 0.4 to 0.55 L/L) and leukocytosis (16.1 × 109 WBCs/L; reference interval, 6 × 109 WBCs/L to 13 × 109 WBCs/L) characterized by mature neutrophilia (12.3 × 109 neutrophils/L; reference interval, 3 × 109 neutrophils/L to 10.5 × 109 neutrophils/L). Serum biochemical analysis indicated low-normal BUN (6 mg/dL; reference interval, 5 to 21 mg/dL) and creatinine (0.5 mg/dL; reference interval, 0.3 to 1.2 mg/dL) concentrations, with all other values within reference limits.

On thoracic radiographs, pleural fissure lines with mild pleural effusion and a mild patchy interstitial to alveolar infiltrate within the mid to ventral region of the right caudal lung lobe could be seen. Thoracocentesis yielded scant pleural fluid; cytologic examination of the fluid sample indicated marked suppurative inflammation and the presence of intracytoplasmic rods consistent with a diagnosis of bacterial sepsis. Aerobic culture of a sample of the pleural fluid yielded small numbers of Streptococcus canis biotype 2. Anaerobic culture did not yield any bacterial growth.

Because these diagnostic results were considered to be most consistent with a migrating foreign body with possible secondary infectious pulmonary parenchymal and pleural space disease, thoracic CTa was performed. The patient was premedicated with oxymorphone (0.05 mg/kg [0.023 mg/lb], SC) and atropine (0.02 mg/kg [0.009 mg/lb], SC), an IV catheter was placed in a cephalic vein, and general anesthesia was induced with propofol (4 mg/kg [1.8 mg/lb], IV) and midazolam (0.25 mg/kg [0.11 mg/lb], IV). The patient was orotracheally intubated, and anesthesia was maintained by means of administration of isoflurane in oxygen. Pre- and postcontrast CT images were acquired with 2.5-mm slice thickness in helical mode in a lung algorithm. There was a focal alveolar pattern evident in the dependent portion of the right caudal lung lobe (Figure 1) associated with thickening of the pleura. A linear hyperattenuating structure extending from the region of the alveolar pattern in the right caudal lung lobe to the most caudal aspect of the right middle lung lobe was thought to represent a foreign body. The remaining lung parenchyma appeared normal.

Figure 1—
Figure 1—

Transverse CT images (window width, 1,400 Hounsfield units [HUs]; window level, 500 HUs) of the thorax of a 17-month-old sexually intact male Vizsla (dog 1) with migrating intrathoracic grass awns. A—A focal alveolar pattern is evident in the dependent portion of the right caudal lung lobe (arrows). B—Caudal to the region described in A, the pleura is thickened (curved arrow) and there is a linear structure extending into the right caudal lung lobe (arrowhead). This was identified as a grass awn during VATS and was surgically retrieved from the pleural space in this region.

Citation: Journal of the American Veterinary Medical Association 249, 2; 10.2460/javma.249.2.214

After completion of CT, during the same period of general anesthesia, the patient underwent bronchoscopic examination by passage of a bronchoscope through the lumen of the endotracheal tube; this was performed first by means of a 4.9-mm × 110-cm videoendoscopeb followed by use of a 2.5-mm × 100-cm flexible fiberoptic bronchoscope.c A 2-cm-long grass awn surrounded by purulent material was identified and extracted from the left caudal lobar bronchus with grasping forceps. A second grass awn was visualized distally in a bronchus leading to the ventral portion of the accessory lobe, but was unable to be retrieved because of the small diameter of the bronchus.

Following bronchoscopy, with general anesthesia maintained, the dog was prepared for surgery and positioned in left lateral recumbency. The right hemithorax was clipped and prepared by means of standard aseptic technique. A double-lumen endobronchial tubed was inserted into the left mainstem bronchus with bronchoscopic assistancec by use of a previously described technique,1 and the left hemithorax was ventilated. For maintenance of anesthesia, ventilation was adjusted to maintain end-tidal partial pressure of carbon dioxide within the reference range (35 to 45 mm Hg). A 6-mm-diameter, 6.5-cm-long threaded trocarless cannulae with the 1-way valve removed was positioned in the fifth intercostal space at the level of the mid thorax and used for introduction of a 5-mm, 30° telescope.f Two additional 6-mm cannulae were placed to establish instrument ports in the dorsal and ventral thirds of the sixth intercostal space to allow triangulation around the caudal portion of the thorax. The right hemithorax was visually inspected, and an adhesion between the diaphragm and thoracic wall caudal to the right caudal lung lobe was identified. This adhesion was bluntly dissected, revealing purulent exudate and a grass awn partially embedded in the thoracic wall (Figure 2). A combination of blunt dissection and a monopolar electrosurgical J-hookg was used to lyse the adhesion and free the plant material for removal. The 4-cm-long grass awn was removed from the body wall with grasping forceps and then recovered through one of the cannulae (Supplemental Video S1, available at http://avmajournals.avma.org/doi/suppl/10.2460/javma.249.2.214). A fibrinous attachment between the right middle and right cranial lung lobes was released with a blunt probe. The right cranial and right middle lung lobes were then inspected and appeared grossly normal. Because of the previous bronchoscopic confirmation of a grass awn in the accessory lobe, a thoracoscopic accessory lung lobectomy was performed despite the grossly normal appearance of the lung lobe. The pleural reflection was penetrated ventral to the phrenic nerve with the J-hook electrosurgical probe, taking care not to damage the nerve. The accessory lung lobe was grasped and manipulated to a position medial and dorsal to the vena cava in preparation for removal, and the pulmonary ligament was severed with the electrosurgical probe. An 11.5-mm-diamter thoracic cannulah was placed in the ventral aspect of the seventh intercostal space to allow introduction of an endoscopic surgical stapler.i With a 3.5-mm leg length, 60-mm-long staple cartridge, the accessory lung lobe hilus was transected (Supplemental Video S2, available at http://avmajournals.avma.org/doi/suppl/10.2460/javma.249.2.214). After staple cartridge discharge, minor encroachment of the most distal staples into the caudomedial aspect of the left caudal lung lobe was noted. The 2 lung lobes were gently separated with the blunt probe, the area of staple encroachment was ventilated, and the lung lobe surface was flushed with saline (0.9% NaCl) solution to test for air leakage, which did not occur. No further action was taken to remove the encroaching staples. The transected lung lobe was then removed via a specimen retrieval bag.j A 24F thoracostomy tube was placed on the right side of the thorax, entering at the ninth intercostal space. The surgical port sites were closed routinely. The duration of surgery was 2 hours and 5 minutes, from placement of the first cannula to evacuation of the thorax via the thoracostomy tube following closure of all port sites. Postoperatively, and for the duration of hospitalization, the dog was administered ampicillin-sulbactamk (50 mg/kg [22.7 mg/lb], IV, q 8 h), enrofloxacinl (10 mg/kg [4.5 mg/lb], IV, q 24 h), and fentanyl citratem (0.05 μg/kg/min, IV as a continuous rate infusion).

Figure 2—
Figure 2—

Thoracoscopic image obtained during VATS of the right hemithorax of dog 1. The tip of the blunt probe is located at an adhesion between the diaphragmatic crus and the thoracic wall, caudal to the right caudal lung lobe. A grass awn was partially embedded in this area.

Citation: Journal of the American Veterinary Medical Association 249, 2; 10.2460/javma.249.2.214

The resected lung lobe was submitted for histologic examination, which revealed severe neutrophilic bronchitis with intraluminal plant material and secondary bronchopneumonia. Additional findings included multifocal bronchial smooth muscle hypertrophy (bronchiolitis obliterans) with focal chronic interstitial pneumonia and pneumocyte hyperplasia, suggestive of possible previous bouts of bronchitis. No bacteria or fungi were identified.

The dog recovered uneventfully from surgery, and the thoracostomy tube was removed 12 hours later. The dog was discharged 48 hours after surgery with a 4-week course of amoxicillin-clavulanic acidn (13.75 mg/kg [6.25 mg/lb], PO, q 12 h) and enrofloxacin (5 mg/kg [2.3 mg/lb], PO, q 24 h). Carprofeno (2.2 mg/kg [1 mg/lb], PO, q 12 h) and tramadol hydrochloridep (4 mg/kg [1.8 mg/lb], PO, q 8 to 12 h) were prescribed for 5 to 7 days for analgesia and anti-inflammatory effects.

A telephone interview with the owners 31 months after surgery revealed that the dog was alive and had made an uneventful and apparently complete recovery from surgery, with no evidence of recurrence of clinical signs. However, no follow-up diagnostic imaging was performed.

A 2-year-old 33-kg (73-lb) spayed female mixed-breed dog (dog 2) was examined at our hospital because of a 10-day history of coughing. Prior to examination, the owner observed a grass awn in the back of the dog's mouth but could not retrieve it. On physical examination, the dog was febrile (40°C [104°F]) and tachypneic (110 breaths/min) but appeared well hydrated, with harsh lung sounds on auscultation bilaterally. Results of a CBC revealed an Hct within reference limits (0.45 L/L), leukocytosis (28.7 × 109 WBC's/L) characterized by neutrophilia (23.2 × 109 neutrophils/L) with band neutrophils (0.57 × 109 band neutrophils/L; reference interval, rare bands × 109/L) and slight toxic changes, and monocytosis (2 × 109 monocytes/L; reference interval, 0.15 × 109 monocytes/L to 1.2 × 109 monocytes/L). Results of serum biochemical analysis were within reference limits. Thoracic radiography did not reveal any abnormalities; however, because of the clinical suspicion for a migrating grass awn, CTa of the thorax and bronchoscopic examination was recommended. Treatment with ampicillin-sulbactam (30 mg/kg [13.6 mg/lb], IV, q 8 h) was initiated.

The patient was premedicated with hydromorphone (0.05 mg/kg, IV), an IV catheter was placed in a cephalic vein, and general anesthesia was induced with propofol (4 mg/kg, IV) and midazolam (0.25 mg/kg, IV), titrated to effect (total dose of propofol, 132 mg; total dose of midazolam, 8.25 mg). The patient was orotracheally intubated, and anesthesia was maintained with administration of isoflurane in oxygen. On induction of general anesthesia, oropharyngeal examination revealed a grass awn in the right tonsillar crypt that was extracted manually. Pre- and postcontract CT images were acquired with 2.5-mm slice thickness in helical mode in a lung algorithm. There was scant right cranioventral pleural effusion, a focal peribronchial alveolar region in the left caudal lung lobe with marked bronchial thickening and bronchiectasis, and regional ill-defined interstitial attenuation (Figure 3). Bronchoscopy was performed with a 4.9-mm × 110-cm videoendoscopeb passed through the lumen of the endotracheal tube, which revealed a focally dilated airway with a thickened bifurcation in the left caudal lung lobe containing a mild amount of purulent material. No foreign body was visualized.

Figure 3—
Figure 3—

Transverse CT images (window width, 1,400 HUs; window level, 500 HUs) of the thorax of a 2-year-old spayed female mixed-breed dog (dog 2). A—Marked bronchial thickening and dilation (arrowhead) and a regional ill-defined interstitial density (small arrow) are seen in the left caudal lung lobe. B—A focal alveolar pattern (arrow) with pleural thickening (curved arrow) is evident in the left caudal lung lobe. The patient underwent VATS with resection of the left caudal lung lobe and removal of a grass awn from the left caudal hemithorax.

Citation: Journal of the American Veterinary Medical Association 249, 2; 10.2460/javma.249.2.214

After completion of CT and the bronchoscopic examination, bronchoscopic-assisted placementc of a double-lumen endotracheal tube was used to achieve selective ventilation of the right hemithorax. The dog was initially positioned in dorsal recumbency, clipped of hair, and prepared for surgery by means of standard aseptic technique. A 6-mm-diameter threaded trocarless cannula with the 1-way valve removed was placed in a subxiphoid location, and the thorax was then examined with a 5-mm, 30° telescope. A small amount of pink-tinged purulent fluid was identified. A second 6-mm-diameter cannula was positioned in the left fifth intercostal space. Mediastinal attachments to the sternum were sectioned with a vessel-sealing device.q The right hemithorax was visually inspected, and a small amount of pink-tinged purulent fluid was removed. A sample of the fluid was submitted for cytologic examination and microbial culture with susceptibility testing. The thorax was lavaged with 1 L of warm sterile saline solution via the thoracoscopic cannulae, and the lavage solution was removed by means of suction. At the completion of lavage and without redraping the patient or compromising the sterile surgical field, the straps used to stabilize the patient in dorsal recumbency were loosened and the dog was repositioned in right lateral recumbency for the second phase of surgery.

A third 6-mm-diameter cannula was positioned in the fifth intercostal space, approximately 3 cm ventral to the previously created port, to facilitate exploration of the left hemithorax. A single grass awn was visualized in the left caudal hemithorax at the insertion of the left crus of the diaphragm to the thoracic wall (Figure 4). The grass awn was grasped and removed with laparoscopic forceps. An additional 11.5-mm-diameter cannula was positioned in the ventral third of the 10th intercostal space for left caudal lung lobectomy. The left pulmonary ligament was sectioned with a monopolar electrosurgical J-hook probe. The left caudal lung lobe was resected with two 3.5-mm endoscopic surgical stapleri cartridges: the first was 60 mm in length, and the second was 45 mm in length. Once free from its attachments, the lung lobe was placed into a specimen retrieval bag and removed through a 3- to 4-cm enlargement of the 11.5-mm-diameter cannula portal incision. A 20F thoracostomy tube was placed through a separate incision, entering the thorax at the ninth intercostal space.

Figure 4—
Figure 4—

Thoracoscopic image obtained during VATS of the left hemithorax of dog 2. A grass awn was located free within the pleural cavity at the insertion of the left diaphragmatic crus and the thoracic wall and was removed with grasping forceps.

Citation: Journal of the American Veterinary Medical Association 249, 2; 10.2460/javma.249.2.214

The port sites were closed in a routine fashion, and air and fluid were evacuated from the thorax via the thoracostomy tube. The duration of the surgery was 2 hours and 45 minutes. For the duration of hospitalization, the dog continued to receive ampicillin-sulbactam (30 mg/kg, IV, q 8 h) and fentanyl citrate (0.1 μg/kg/min [0.045 μg/kg/lb] at a continuous rate infusion, IV).

Cytologic examination of a pleural fluid sample collected at the time of surgery revealed marked suppurative inflammation, mild hemorrhage, and mild mesothelial hyperplasia, with mildly degenerate neutrophils, few macrophages, and occasional reactive mesothelial cells. Aerobic and anaerobic culture of the pleural fluid sample yielded no bacterial growth. Histologic examination of a sample of the excised left caudal lung lobe was performed and revealed severe, diffuse, chronic, neutrophilic and histiocytic lobar pneumonia with multiple intraparenchymal abscesses and marked neutrophilic pleuritis with subpleural granulation tissue and mesothelial hyperplasia. No grass awn fragments or other plant material was present in the lobar tissue, suggesting that the grass awn retrieved thoracoscopically had migrated through the left caudal lung lobe into its location within the caudal portion of the pleural cavity.

The dog recovered from surgery without apparent complications. The thoracostomy tube was removed 12 hours after surgery, and the dog was discharged 48 hours after surgery. Amoxicillin-clavulanic acid (13.75 mg/kg, PO, q 12 h for 12 days) and tramadol hydrochloride (3 mg/kg, PO, q 8 h for 7 days) were dispensed.

A telephone interview with the owners 18 months after surgery suggested complete recovery from surgery with no apparent recurrence of clinical signs during the follow-up period. No further diagnostic imaging was performed.

Discussion

Grass awn migration is a common cause of foreign body disease in dogs and especially affects hunting and working breeds, presumably because of increased exposure.2–4 Grass awns have a sharp, pointed tip, with sharp barbs extending backward, enabling penetration and progressive unidirectional migration in the body. Inhalation of grass awns is common in dogs in certain geographic locations and can result in penetration of a bronchus, followed by migration of the plant material through the lung parenchyma, where it can cause pneumothorax, pyothorax, or lobar consolidation.5 Although it is impossible to confirm the pathway of migration in the 2 patients of this report, we suggest it was most likely that inhalation into the large bronchi occurred followed by migration through the parenchyma of the affected lung lobes. The results of CT were considered indications for surgical management in these patients despite the fact that grass awn migration out of the parenchyma and into the pleural space could not be definitively confirmed preoperatively in either dog. Previous studies have evaluated radiographic, ultrasonographic, and CT features of intrathoracic grass awn migration.4,6 Radiographic findings include focal interstitial pulmonary opacities, pleural effusion, pleural thickening, and pneumothorax.5,6 Computed tomography has been reported6 to be more sensitive than radiography alone for evaluation of cats and dogs with this condition. It can enable localization of the diseased lung region, determination of the extent of involvement, identification of the migration tract, and visualization of the foreign body in some cases.6 However, no study has compared the presence of grass awns at surgery with results of preoperative CT or defined sensitivity or specificity of CT for detection and localization of intrathoracic grass awns. We would also stress that the absence of radiographic evidence cannot rule out the presence of a foreign body, especially in acute cases because the results of thoracic radiography may be normal in up to a third of cases.4–6

Both of the dogs described in the present report underwent preoperative bronchoscopic evaluations of all accessible divisions of the lungs. We believe that this is an important diagnostic step in these cases given the propensity for dogs to inhale multiple grass awns in a single incident. One dog of the present report (dog 2) had a grass awn in the tonsillar crypt, and the other dog (dog 1) had grass awns in the left caudal and accessory lung lobes. The dog with an accessory lung lobe grass awn had an apparently normal accessory lung lobe on preoperative CT and during our initial surgical examination, and this lobe would not have been removed by the surgeon had the preoperative bronchoscopic examination not revealed the presence of the grass awn, which could not be retrieved by means of bronchoscopy. We suggest that it is therefore likely that further migration, abscess formation, or both of the accessory lung lobe would have been a sequela to leaving this lung lobe in place. This would likely have resulted in further morbidity and required a second surgery. In a previous study5 of the use of bronchoscopy for evaluation and treatment of bronchial foreign bodies, 21% (5/24 cases) of dogs had multiple grass awns, and in 4 of those cases, the grass awns were located in different lung lobes. As such, we recommend that preoperative bronchoscopic examination be considered to evaluate patients for the presence of grass awns that may be undetected with CT. These 2 modalities provided complementary information in dogs of the present report given the propensity for CT to fail to detect grass awns that remain within the bronchial tree but which can be visualized bronchoscopically, and given the ability of CT to detect accompanying pleural space disease, lobar consolidation, and possible migration patterns of grass awns within the tissues of the thoracic wall.

When minimally invasive surgical approaches are considered, it is critical that careful case selection be used to maximize the chance of a successful outcome. In both dogs of this report, a discrete site of pulmonary abnormality could be identified preoperatively with the combined use of radiography, CT, and bronchoscopy. Furthermore, the extent of disease within the thorax was deemed to be very focal with few indicators of generalized chronic inflammation such as effusion, pleural thickening, or abscess formation.5,6 We suggest that it is critical to be highly selective with the use of VATS for treatment of intrathoracic grass awn migration. In our clinical practice, we have largely chosen to use VATS for the treatment of acute cases in which focal disease is believed to be present and there is a high level of suspicion regarding lesion location on the basis of results of preoperative diagnostic evaluation. As such, at our hospital, intrathoracic grass awn migration is only rarely treated with VATS because most dogs evaluated have a more chronic history and thus have more generalized thoracic inflammatory changes at the time of surgery, as has been described previously.5 The concern in those cases is whether VATS can be as effective as open thoracic surgery (via intercostal thoracotomy or median sternotomy) in locating migrating grass awns and providing adequate pleural debridement and lavage. Further studies are needed with larger case numbers to evaluate this question more critically.

The first dog of this report was positioned in lateral recumbency with intercostal port placement, with the second dog initially positioned in dorsal recumbency with a subxiphoid telescope port, transection of ventral mediastinal attachments, and examination of both hemithoraces. We suggest that there are advantages and disadvantages to these 2 approaches when performing VATS. In the first patient, preoperative evaluation did not indicate pleural space disease in the left hemithorax; thus, we decided that proceeding initially with the dog in lateral recumbency was reasonable. In the second patient, the presence of pleural effusion in the right hemithorax and lung consolidation in the left caudal lobe on preoperative CT images prompted our decision for the initial approach with the patient in dorsal recumbency and a subxiphoid port that allowed bilateral hemithorax evaluation to avoid potentially overlooking lesions in the right hemithorax. Whereas both approaches appeared to be successful in these 2 patients, an exploration of only 1 hemithorax prevents assessment of possible contralateral lesions that could be missed on CT. Therefore, unless there is a high degree of certainty that 1 hemithorax is completely free of disease, we suggest that exploration of both hemithoraces with the patient positioned in dorsal recumbency be performed initially, followed by repositioning into the appropriate recumbency for lung lobectomy if indicated.

The use of video-assisted lung lobectomy is becoming a well-established alternative to open lung lobectomy in small animal patients.7–9 However, to our knowledge, only 1 previous report7 exists describing video-assisted foreign body removal and lung lobectomy. In addition, 1 patient of this report also underwent accessory lung lobectomy by means of VATS, which has only been described once previously.10 For these cases, we suggest that it is helpful to displace the accessory lobe medial and dorsal to the vena cava prior to stapler placement. This maneuver facilitates placement of the surgical stapler closer to the hilus of the lobe, allowing a more complete lobectomy to be performed. Whereas VATS provides excellent visualization and magnification, it remains unknown how it compares with open thoracic surgery in terms of the ability to fully evaluate all areas of the thoracic cavity. Furthermore, 1-lung ventilation, as was used successfully for the 2 dogs of the present report, is generally considered necessary to achieve successful video-assisted lung lobectomy. The main disadvantages associated with video-assisted lung lobectomy include the cost of the procedure, increased surgical time, the need for specialized equipment and instrumentation, and the technical skill required to perform the procedure.7–9 However, decreased postoperative pain and fewer postoperative wound complications may represent important advantages.11 Treatment of the patients described in this report with VATS minimized the potential disadvantages associated with open thoracotomy. With careful case selection, successful management of intrathoracic grass awn migration in dogs can be achieved by means of VATS. Further investigation is necessary to evaluate whether VATS is as effective as traditional open thoracotomy for dogs with this condition.

ABBREVIATIONS

VATS

Video-assisted thoracic surgery

Footnotes

a.

HiSpeed FX/I, GE Medical Systems, Milwaukee, Wis.

b.

GIF N180, Olympus Corp, Melville, NY.

c.

60003VB, Karl Storz Veterinary Endoscopy, Goleta, Calif.

d.

Rusch Robert-Shaw Endobronchial tube, Teleflex Medical, Durham, NC.

e.

Endotip, Karl Storz Veterinary Endoscopy, Goleta, Calif.

f.

Hopkins II laparoscope, Karl Storz Veterinary Endoscopy, Goleta, Calif.

g.

Laparoscopic wire J-hook, Covidien Inc, Mansfield, Mass.

h.

Thoracoport, Covidien Inc, Mansfield, Mass.

i.

EndoGIA stapler, Covidien Inc, Mansfield, Mass.

j.

Monarch bag, Applied Medical, Rancho Santa Margarita, Calif.

k.

Unasyn, MITIM, Brescia, Italy.

l.

Baytril, Bayer Animal Health, Berkeley, Calif.

m.

Fentanyl citrate, Hospira Inc, Lake Forest, Ill.

n.

Clavamox, Zoetis Inc, Florham Park, NJ.

o.

Rimadyl, Zoetis Inc, Florham Park, NJ.

p.

Tramadol hydrochloride, Amneal, Hauppauge, NY.

q.

Ligasure, Covidien Inc, Mansfield, Mass.

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  • 11. Walsh PJ, Remedios AM, Ferguson JF, et al. Thoracoscopic versus open partial pericardectomy in dogs: comparison of postoperative pain and morbidity. Vet Surg 1999; 28: 472479.

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  • Figure 1—

    Transverse CT images (window width, 1,400 Hounsfield units [HUs]; window level, 500 HUs) of the thorax of a 17-month-old sexually intact male Vizsla (dog 1) with migrating intrathoracic grass awns. A—A focal alveolar pattern is evident in the dependent portion of the right caudal lung lobe (arrows). B—Caudal to the region described in A, the pleura is thickened (curved arrow) and there is a linear structure extending into the right caudal lung lobe (arrowhead). This was identified as a grass awn during VATS and was surgically retrieved from the pleural space in this region.

  • Figure 2—

    Thoracoscopic image obtained during VATS of the right hemithorax of dog 1. The tip of the blunt probe is located at an adhesion between the diaphragmatic crus and the thoracic wall, caudal to the right caudal lung lobe. A grass awn was partially embedded in this area.

  • Figure 3—

    Transverse CT images (window width, 1,400 HUs; window level, 500 HUs) of the thorax of a 2-year-old spayed female mixed-breed dog (dog 2). A—Marked bronchial thickening and dilation (arrowhead) and a regional ill-defined interstitial density (small arrow) are seen in the left caudal lung lobe. B—A focal alveolar pattern (arrow) with pleural thickening (curved arrow) is evident in the left caudal lung lobe. The patient underwent VATS with resection of the left caudal lung lobe and removal of a grass awn from the left caudal hemithorax.

  • Figure 4—

    Thoracoscopic image obtained during VATS of the left hemithorax of dog 2. A grass awn was located free within the pleural cavity at the insertion of the left diaphragmatic crus and the thoracic wall and was removed with grasping forceps.

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  • 11. Walsh PJ, Remedios AM, Ferguson JF, et al. Thoracoscopic versus open partial pericardectomy in dogs: comparison of postoperative pain and morbidity. Vet Surg 1999; 28: 472479.

    • Crossref
    • Search Google Scholar
    • Export Citation

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