Bovine Thoracoscopy: Surgical Technique and Normal Anatomy Doreen Scharner, Dr. Med. Vet., Katja Dorn, and Walter Brehm, Prof. Dr. Med. Vet., Diplomate ECVS Large Animal Clinic for Surgery, University of Leipzig, Leipzig, Germany
Corresponding Author Doreen Scharner, Dr. Med. Vet., Large Animal Clinic for Surgery, University of Leipzig, An den Tierkliniken 2, 04103 Leipzig, Germany. E‐mail: [email protected] Submitted October 2012 Accepted October 2013 DOI:10.1111/j.1532-950X.2013.12086.x
Objective: To describe a surgical technique for thoracoscopy and report visible anatomy within the thoracic cavity of standing cattle. Study design: Prospective study. Animals: Adult clinically healthy Holstein–Friesian cows (n ¼ 15). Methods: Each cow had four thoracoscopic examinations. Initially, the left hemithorax was examined after passive lung collapse, then again 24 hours later after CO2 insufflation. The right hemithorax was examined 24 hours later after passive lung collapse and again 24 hours later after CO2 insufflation. Results: CO2 insufflation did not significantly improve visibility within the pleural space. Collapsed lung, aorta, esophagus, diaphragm, and azygos vein were readily viewed; however, the pericardial region was not consistently visible. Minor laceration of the lung occurred in 1 cow with adhesions, otherwise there were no intra‐ or postoperative complications. All cows recovered without signs of discomfort. No local swelling or emphysema occurred at the portals. Conclusions: Thoracoscopy can be safely performed on healthy standing cattle.
INTRODUCTION Thoracoscopy is a minimally invasive procedure to examine the pleural space with rigid or flexible endoscopes,1 and can complement conventional diagnostic methods (clinical examination, ultrasonography, radiography, and endoscopy). The role of imaging procedures is becoming increasingly important in bovine medicine.2 We are only aware of a single case report in cattle where thoracoscopy was used as an additional technique for diagnosis and treatment of pericardial lymphoma.3 Our purpose was to describe a thoracoscopic technique in standing cattle with and without CO2 insufflation, report visible structures and potential operative and postoperative complications. We hypothesized that (1) thoracoscopy can be safely performed in standing cattle; (2) most structures within the thoracic cavity would be visible; and (3) intrapleural CO2 insufflation would significantly improve observation within the pleural space.
MATERIAL AND METHODS The study was approved by the Animal Welfare Commission (TVV‐No. 14/03) and was part of a larger study on assessment of cardiovascular and respiratory responses to thoracoscopy in healthy standing cattle. Cattle Healthy adult female Holstein–Friesian cattle (n ¼ 15; aged 3– 9 years; mean, 5 years) with a mean weight of 483 kg were
studied. Clinical examination and blood analysis (hematology, serum biochemical profile, and blood gases) were used to assess that the cows were healthy. Cows were housed in individual boxes. Study Design Each cow had 4 thoracoscopic examinations. Initially, the left hemithorax was examined after passive lung collapse, and then 24 hours later the left hemithorax was examined after CO2 insufflation. Twenty‐four hours later the right hemithorax was examined after passive lung collapse and then 24 hours later after CO2 insufflation. Five cows were examined in the 8th, 9th, or 10th intercostal space, respectively. The cows were selected randomly for the attribution of the intercostal spaces. A simple randomization method (drawing numbers) was used.
Preoperative Preparation Cows had free access to food and water before surgery. For thoracoscopy, cows were restrained in standing stocks and the tail was tied to the halter on the contralateral side to the surgical procedure. The skin extending from the shoulder joint to the caudal angle of the scapula and caudally to the paralumbar fossa was clipped and aseptically prepared. A sterile drape fixed to the skin by adhesive tape was used to cover the thorax and abdomen. Portal sites were anesthetized with 2% procaine (15–20 mL) injected locally into the subcutaneous, muscular, and pleural tissues of the selected intercostal space.
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
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Bovine Thoracoscopy
Scharner, Dorn, and Brehm
Surgical Technique
within‐subject groups was performed using McNemar’s x2 test. Analyses were performed with software (SPSS15, SPSS Software GmbH, Munich, Germany) and significance was set at P .05).
Figure 2 Right pleural space, 9th intercostal space with telescope advanced dorsocranially RL, right lung; IM, intercostal muscles; LC, longus colli muscle; AZ, right azygos vein; 1, 2, 3: dorsal intercostal veins of ribs 2, 3, 4; II, III, IV, 2nd, 3th, 4th rib; arrows: pulmonary ligament.
DISCUSSION Thoracoscopic examination was successfully performed by using a 30°, 57‐cm long, and 10‐mm diameter rigid endoscope
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
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Bovine Thoracoscopy
Table 1
Scharner, Dorn, and Brehm
Anatomic Structures Visible During Left and Right Standing Thoracoscopy
Anatomic Structure Pleural surfaces of ribs 3rd through 12th Intercostal muscles Longus colli muscle Sympathetic nerve fibers (stellate ganglion) Left costocervical trunk Right costocervical trunk Left costocervical vein Right costocervical vein Brachiocephalic trunk Dorsal and lateral lung surfaces Middle and accessory lobe (parts) Diaphragmatic surface of the caudal lung lobe (parts) Pulmonary ligament Bronchoesophageal artery and vein Oesophagus (thoracal part) Aorta (thoracal part) Azygos vein Dorsal intercostal veins Dorsal intercostal arteries Pulmonary veins Thoracic duct Thoracic aortic and intercostal lymph nodes (thoracic dorsal lymph center) Caudal mediastinal lymph nodes Sympathetic trunk (thoracic part) Vagus nerve (dorsal branche) Vagus nerve (ventral branche) Recurrent laryngeal nerve Phrenical nerve Phrenical vein and branches Psoas major muscle Diaphragm (parts) Oesophagal hiatus Aortic hiatus Heart base (pericardial adipose tissue)
Left Hemithorax
Right Hemithorax
Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Not consistently seen Yes Yes Yes Yes Yes No No Yes Yes Yes Yes No No No Yes Yes Yes No Yes Yes (3/15)
Yes Yes Yes consistently No consistently No consistently No Yes Yes Yes Yes consistently Yes Yes Yes Yes Yes No No Yes Yes Yes Yes No No No Yes Yes Yes No Yes Yes (1/15)
Not Not Not
Not
seen seen seen
seen
Under CO2 insufflation.
with video assistance in standing healthy adult Holstein– Friesian cattle. Restraint in stocks and use of local infiltration anesthesia at portal sites was sufficient for thoracoscopic examination. Some discomfort evident by the cow shifting back and forth was only observed when the endoscope was advanced cranially in the 8th intercostal space. This ceased when the endoscope was moved in a ventral, dorsal or caudal direction. Although not needed in these cows, supplemental analgesia and sedation could be provided by use of intravenous (IV) xylazine in combination with an intercostal nerve block. However, Peroni et al.4 reported that despite use of regional and local anesthesia in combination with IV detomidine in horses, signs of pain occurred when a thoracoscopic approach in the 8th intercostal space was used. Because of the risks associated with general anesthesia and the development of tympany because of recumbency, surgical procedures should preferentially be done in standing cattle using local anesthesia.3,5,6 Thoracoscopic pericardiotomy in a cow was performed solely using local anesthesia.3 Before inserting the trocar/cannula system into the pleural space we used a teat cannula to create pneumothorax with the intention of avoiding visceral damage.3 In our opinion, this is a
88
safe method. In 1 cow, trocar insertion resulted in a small pulmonary parenchymal injury with slight hemorrhage, because of adhesions between the costal and the pulmonary pleura; however, thoracic exploration was continued uneventfully. Inadequate lung collapse leading to a pulmonary parenchymal injury has been reported during equine thoracoscopy4 and in small animals.7 From our experience, adequate examination of the intrapleural structures can be best achieved using the 9th intercostal space with the portal located at the level of the ventral margin of the tuber coxa. Although the 8th intercostal space might be preferable for examination of the cranial pleural space, it is less desirable for general thoracoscopic examination because the reduced flexibility of the sternal ribs contributes to discomfort during examination, a phenomenon also reported in equine thoracoscopy.4,8 Successful use of the 8th intercostal space was reported for pericardiotomy in a cow with lymphoma.3 Minimal side effects were observed in these cows. One cow had mild coughing during insufflation; however, this ceased when negative pressure was reestablished. Several reports describe coughing during thoracoscopic interventions in horses and people.8–13 We recommend use of cannulas with
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
Scharner, Dorn, and Brehm
Bovine Thoracoscopy
Figure 3 Left pleural space, 10th intercostal space with telescope advanced dorsomedially A: thoracic aorta; 1, 2, 3: dorsal intercostal veins of ribs 8, 9, 10; IM, intercostal muscles; AZ, left azygos vein; VIII, IX, X, head of ribs 8, 9, 10; ST, thoracic portion of sympathetic trunk; black arrow: lymph node (belongs to the dorsal thoracic lymph center); white arrows: dorsal intercostal arteries.
Figure 5 Right pleural space, 10th intercostal space with telescope advanced slightly ventrocranially. RL, right lung; TC, tendinous center of diaphragm; IX, 9th rib; black arrow: phrenic vein; white arrows: acute margin of right caudal lung lobe; IM, intercostal muscles.
a side stopcock, to which a suction tube can be attached to facilitate rapid control of intrapleural pressure and relief of pneumothorax if needed. One cow had mild pelvic limb tremor that only occurred during the initial thoracoscopic examination and no other discernible signs of discomfort or agitation were observed. Standing thoracoscopy provided good viewing of the dorsal and lateral structures of the thorax. Collapsed lung,
aorta, esophagus, diaphragm, and azygos vein were readily viewed; however, the pericardial area was not consistently visible. The thoracic duct, pulmonary veins, and esophageal hiatus of cattle were not visible, contrary to findings in horses.4,8 One reason for this may be that the increased connective tissue contained in the bovine mediastinum results in less mediastinal transparency than in horses.14 The pulmonary veins and esophageal hiatus were obscured by
Figure 4 Left pleural space, 10th intercostal space with telescope advanced dorsocaudally ST, thoracic part of sympathetic trunk; A, thoracic aorta; CM, caudal mediastinal lymph node; black arrow: aortic hiatus; LP, lumbar part of diaphragm; TC, tendinous center of diaphragm; PM, psoas major muscle; XII, 12th rib; white arrow: costal attachment of diaphragm to the rib; black arrows (dotted line): branches of phrenic vein.
Figure 6 Left pleural space, CO2 insufflation, 8th intercostal space with telescope advanced ventrocranially. CRL, caudal part of the cranial lobe of the left lung; CAL, caudal lobe of the left lung; IM: intercostal muscles; V, 5th rib; H, auricle surface of heart; white arrow (dotted line): acute margin of the left cranial lung lobe; white arrow (solid line): caudal interlobular fissure.
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
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Scharner, Dorn, and Brehm
the collapsed lung. We do not know if a higher insufflation pressure would have improved visibility of these structures or if withholding food preoperatively would improve overall intrathoracic observation. CO2 insufflation of the pleural space performed under general anesthesia during thoracoscopy in horses and dogs does improve intrathoracic viewing.15–17 In standing cattle, CO2 insufflation to 5 mmHg did not improve viewing of intrathoracic structures and particularly not in the right cranial thoracic space. One possible explanation might be that the right bovine lung is larger than the left and, therefore, occupies a wide part of the right pleural space despite being collapsed.14 Insufflation to 5 mmHg made endoscopic inspection of the heart and pericardial tissue possible in four cows. In 1cow, the heart was visible on the right side without insufflation, but only when the endoscope was directed between the diaphragm and caudal lung lobe. One limitation of our study is the absence of preoperative thoracic radiographs to rule out the presence of some pathologic findings, like masses, thoracic effusions, inflammatory pulmonary diseases amongst others that could have influenced our results, although other abnormalities like adhesions would likely not be detected. Another limitation was the order of examinations, which was always identical. In our experience with horses, beginning bilateral thoracoscopy on the left side reduces the risk of development of bilateral pneumothorax.8 For this reason, and because we did not know if there might be similar findings in cattle, we decided to begin the procedure on the left side. We did not administer antibiotics despite using the same portal within 24 hours, because these were classified as clean procedures. No postoperative signs of inflammation or infection were observed. Summarily, we found that bovine thoracoscopy can be safely performed on healthy standing cattle without major complications. Because cattle have an intact mediastinum,14 the risk for respiratory problems during thoracoscopy (e.g., bilateral pneumothorax) is considered to be low. Thoracoscopic examination is minimally invasive method and should be considered as a complementary technique to visually explore the intrapleural space, obtain fluid and tissue samples, and to detect and diagnose pulmonary diseases.
REFERENCES 1. Mackey VS, Wheat JD: Endoscopic examination of the equine thorax. Equine Vet J 1985;17:140–142 2. Steiner A: Einsatz bildgebender Verfahren beim Rind. Tierarztl Prax Ausg G Grosstiere Nutztiere 2011;39:275 3. Van Biervliet J, Kraus M, Woodie B, et al: Thoracoscopic pericardiotomy as a palliative treatment in a cow with pericardial lymphoma. J Vet Cardiol 2006;8:69–73 4. Peroni JF, Horner NT, Robinson NE, et al: Equine thoracoscopy: normal anatomy and surgical technique. Equine Vet J 2001;33:231–237 5. Hendrickson DA: Rib resection and pericardiotomy. in Hendrickson DA (ed): Techniques in Large Animal Surgery (ed 3). Ames, IA, Blackwell Publishing, 2007, pp 282–286 6. Ducharme NG, Fubini SL, Rebhun WC, et al: Thoracotomy in adult dairy cattle 14 cases (1979–1991). J Am Vet Med Assoc 1992;200:86–90 7. Walton RS: Video‐assisted thoracoscopy. Vet Clin North Am Small Anim Pract 2001;31:729–759 8. Scharner D: Thorakoskopische Untersuchungen am stehenden sedierten Pferd—Anatomie und Technik. Pferdeheilkunde 2012;28:46–52 9. Raphel CF, Gunson DE: Percutaneous lung biopsy in the horse. Cornell Vet 1981;71:439–448 10. Venner M, Schmidbauer S, Drommer W, et al: Percutaneous lung biopsy in the horse: comparison of two instruments and repeated biopsy in horses with induced acute interstitial pneumopathy. J Vet Intern Med 2006;20:968–973 11. Fair JJ: Anesthesia for thoracoscopy: an overview. AANA J 1994;62:133–138 12. Unzueta MC, Sabaté S, Casas JI, et al: Anesthesia for thoracoscopy. Rev Esp Anestesiol Reanim 1996;43:67–69 13. Dave N, Fernandes S: Anaesthetic implications of paediatric thoracoscopy. J Minim Access Surg 2005;1:8–14 14. Budras K‐D, Wünsche A: Brusthöhle. in Budras K‐D, Wünsche A (eds): Atlas der Anatomie des Rindes. (ed 2). Hannover, Germany, Schlüterche Verlagsgesellschaft, 2002, pp 62–65 15. Vachon AM, Fischer AT: Thoracoscopy in the horse: diagnostic and therapeutic indications in 28 cases. Equine Vet J 1998;30: 467–475
DISCLOSURE
16. Quandt JE: Anesthetic considerations for laser, laparoscopy, and thoracoscopy procedures. Clin Tech Small Anim Pract 1999;14:50–55
The authors report no financial or other conflicts related to this study.
17. Walsh PJ, Remedios AM, Ferguson JF, et al: Thoracoscopic versus open partial pericardectomy in dogs: comparison of postoperative pain and morbidity. Vet Surg 1999;28:472–479
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Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
Corresponding Author Doreen Scharner, Dr. Med. Vet., Large Animal Clinic for Surgery, University of Leipzig, An den Tierkliniken 2, 04103 Leipzig, Germany. E‐mail: [email protected] Submitted October 2012 Accepted October 2013 DOI:10.1111/j.1532-950X.2013.12086.x
Objective: To describe a surgical technique for thoracoscopy and report visible anatomy within the thoracic cavity of standing cattle. Study design: Prospective study. Animals: Adult clinically healthy Holstein–Friesian cows (n ¼ 15). Methods: Each cow had four thoracoscopic examinations. Initially, the left hemithorax was examined after passive lung collapse, then again 24 hours later after CO2 insufflation. The right hemithorax was examined 24 hours later after passive lung collapse and again 24 hours later after CO2 insufflation. Results: CO2 insufflation did not significantly improve visibility within the pleural space. Collapsed lung, aorta, esophagus, diaphragm, and azygos vein were readily viewed; however, the pericardial region was not consistently visible. Minor laceration of the lung occurred in 1 cow with adhesions, otherwise there were no intra‐ or postoperative complications. All cows recovered without signs of discomfort. No local swelling or emphysema occurred at the portals. Conclusions: Thoracoscopy can be safely performed on healthy standing cattle.
INTRODUCTION Thoracoscopy is a minimally invasive procedure to examine the pleural space with rigid or flexible endoscopes,1 and can complement conventional diagnostic methods (clinical examination, ultrasonography, radiography, and endoscopy). The role of imaging procedures is becoming increasingly important in bovine medicine.2 We are only aware of a single case report in cattle where thoracoscopy was used as an additional technique for diagnosis and treatment of pericardial lymphoma.3 Our purpose was to describe a thoracoscopic technique in standing cattle with and without CO2 insufflation, report visible structures and potential operative and postoperative complications. We hypothesized that (1) thoracoscopy can be safely performed in standing cattle; (2) most structures within the thoracic cavity would be visible; and (3) intrapleural CO2 insufflation would significantly improve observation within the pleural space.
MATERIAL AND METHODS The study was approved by the Animal Welfare Commission (TVV‐No. 14/03) and was part of a larger study on assessment of cardiovascular and respiratory responses to thoracoscopy in healthy standing cattle. Cattle Healthy adult female Holstein–Friesian cattle (n ¼ 15; aged 3– 9 years; mean, 5 years) with a mean weight of 483 kg were
studied. Clinical examination and blood analysis (hematology, serum biochemical profile, and blood gases) were used to assess that the cows were healthy. Cows were housed in individual boxes. Study Design Each cow had 4 thoracoscopic examinations. Initially, the left hemithorax was examined after passive lung collapse, and then 24 hours later the left hemithorax was examined after CO2 insufflation. Twenty‐four hours later the right hemithorax was examined after passive lung collapse and then 24 hours later after CO2 insufflation. Five cows were examined in the 8th, 9th, or 10th intercostal space, respectively. The cows were selected randomly for the attribution of the intercostal spaces. A simple randomization method (drawing numbers) was used.
Preoperative Preparation Cows had free access to food and water before surgery. For thoracoscopy, cows were restrained in standing stocks and the tail was tied to the halter on the contralateral side to the surgical procedure. The skin extending from the shoulder joint to the caudal angle of the scapula and caudally to the paralumbar fossa was clipped and aseptically prepared. A sterile drape fixed to the skin by adhesive tape was used to cover the thorax and abdomen. Portal sites were anesthetized with 2% procaine (15–20 mL) injected locally into the subcutaneous, muscular, and pleural tissues of the selected intercostal space.
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
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Bovine Thoracoscopy
Scharner, Dorn, and Brehm
Surgical Technique
within‐subject groups was performed using McNemar’s x2 test. Analyses were performed with software (SPSS15, SPSS Software GmbH, Munich, Germany) and significance was set at P .05).
Figure 2 Right pleural space, 9th intercostal space with telescope advanced dorsocranially RL, right lung; IM, intercostal muscles; LC, longus colli muscle; AZ, right azygos vein; 1, 2, 3: dorsal intercostal veins of ribs 2, 3, 4; II, III, IV, 2nd, 3th, 4th rib; arrows: pulmonary ligament.
DISCUSSION Thoracoscopic examination was successfully performed by using a 30°, 57‐cm long, and 10‐mm diameter rigid endoscope
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
87
Bovine Thoracoscopy
Table 1
Scharner, Dorn, and Brehm
Anatomic Structures Visible During Left and Right Standing Thoracoscopy
Anatomic Structure Pleural surfaces of ribs 3rd through 12th Intercostal muscles Longus colli muscle Sympathetic nerve fibers (stellate ganglion) Left costocervical trunk Right costocervical trunk Left costocervical vein Right costocervical vein Brachiocephalic trunk Dorsal and lateral lung surfaces Middle and accessory lobe (parts) Diaphragmatic surface of the caudal lung lobe (parts) Pulmonary ligament Bronchoesophageal artery and vein Oesophagus (thoracal part) Aorta (thoracal part) Azygos vein Dorsal intercostal veins Dorsal intercostal arteries Pulmonary veins Thoracic duct Thoracic aortic and intercostal lymph nodes (thoracic dorsal lymph center) Caudal mediastinal lymph nodes Sympathetic trunk (thoracic part) Vagus nerve (dorsal branche) Vagus nerve (ventral branche) Recurrent laryngeal nerve Phrenical nerve Phrenical vein and branches Psoas major muscle Diaphragm (parts) Oesophagal hiatus Aortic hiatus Heart base (pericardial adipose tissue)
Left Hemithorax
Right Hemithorax
Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Not consistently seen Yes Yes Yes Yes Yes No No Yes Yes Yes Yes No No No Yes Yes Yes No Yes Yes (3/15)
Yes Yes Yes consistently No consistently No consistently No Yes Yes Yes Yes consistently Yes Yes Yes Yes Yes No No Yes Yes Yes Yes No No No Yes Yes Yes No Yes Yes (1/15)
Not Not Not
Not
seen seen seen
seen
Under CO2 insufflation.
with video assistance in standing healthy adult Holstein– Friesian cattle. Restraint in stocks and use of local infiltration anesthesia at portal sites was sufficient for thoracoscopic examination. Some discomfort evident by the cow shifting back and forth was only observed when the endoscope was advanced cranially in the 8th intercostal space. This ceased when the endoscope was moved in a ventral, dorsal or caudal direction. Although not needed in these cows, supplemental analgesia and sedation could be provided by use of intravenous (IV) xylazine in combination with an intercostal nerve block. However, Peroni et al.4 reported that despite use of regional and local anesthesia in combination with IV detomidine in horses, signs of pain occurred when a thoracoscopic approach in the 8th intercostal space was used. Because of the risks associated with general anesthesia and the development of tympany because of recumbency, surgical procedures should preferentially be done in standing cattle using local anesthesia.3,5,6 Thoracoscopic pericardiotomy in a cow was performed solely using local anesthesia.3 Before inserting the trocar/cannula system into the pleural space we used a teat cannula to create pneumothorax with the intention of avoiding visceral damage.3 In our opinion, this is a
88
safe method. In 1 cow, trocar insertion resulted in a small pulmonary parenchymal injury with slight hemorrhage, because of adhesions between the costal and the pulmonary pleura; however, thoracic exploration was continued uneventfully. Inadequate lung collapse leading to a pulmonary parenchymal injury has been reported during equine thoracoscopy4 and in small animals.7 From our experience, adequate examination of the intrapleural structures can be best achieved using the 9th intercostal space with the portal located at the level of the ventral margin of the tuber coxa. Although the 8th intercostal space might be preferable for examination of the cranial pleural space, it is less desirable for general thoracoscopic examination because the reduced flexibility of the sternal ribs contributes to discomfort during examination, a phenomenon also reported in equine thoracoscopy.4,8 Successful use of the 8th intercostal space was reported for pericardiotomy in a cow with lymphoma.3 Minimal side effects were observed in these cows. One cow had mild coughing during insufflation; however, this ceased when negative pressure was reestablished. Several reports describe coughing during thoracoscopic interventions in horses and people.8–13 We recommend use of cannulas with
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
Scharner, Dorn, and Brehm
Bovine Thoracoscopy
Figure 3 Left pleural space, 10th intercostal space with telescope advanced dorsomedially A: thoracic aorta; 1, 2, 3: dorsal intercostal veins of ribs 8, 9, 10; IM, intercostal muscles; AZ, left azygos vein; VIII, IX, X, head of ribs 8, 9, 10; ST, thoracic portion of sympathetic trunk; black arrow: lymph node (belongs to the dorsal thoracic lymph center); white arrows: dorsal intercostal arteries.
Figure 5 Right pleural space, 10th intercostal space with telescope advanced slightly ventrocranially. RL, right lung; TC, tendinous center of diaphragm; IX, 9th rib; black arrow: phrenic vein; white arrows: acute margin of right caudal lung lobe; IM, intercostal muscles.
a side stopcock, to which a suction tube can be attached to facilitate rapid control of intrapleural pressure and relief of pneumothorax if needed. One cow had mild pelvic limb tremor that only occurred during the initial thoracoscopic examination and no other discernible signs of discomfort or agitation were observed. Standing thoracoscopy provided good viewing of the dorsal and lateral structures of the thorax. Collapsed lung,
aorta, esophagus, diaphragm, and azygos vein were readily viewed; however, the pericardial area was not consistently visible. The thoracic duct, pulmonary veins, and esophageal hiatus of cattle were not visible, contrary to findings in horses.4,8 One reason for this may be that the increased connective tissue contained in the bovine mediastinum results in less mediastinal transparency than in horses.14 The pulmonary veins and esophageal hiatus were obscured by
Figure 4 Left pleural space, 10th intercostal space with telescope advanced dorsocaudally ST, thoracic part of sympathetic trunk; A, thoracic aorta; CM, caudal mediastinal lymph node; black arrow: aortic hiatus; LP, lumbar part of diaphragm; TC, tendinous center of diaphragm; PM, psoas major muscle; XII, 12th rib; white arrow: costal attachment of diaphragm to the rib; black arrows (dotted line): branches of phrenic vein.
Figure 6 Left pleural space, CO2 insufflation, 8th intercostal space with telescope advanced ventrocranially. CRL, caudal part of the cranial lobe of the left lung; CAL, caudal lobe of the left lung; IM: intercostal muscles; V, 5th rib; H, auricle surface of heart; white arrow (dotted line): acute margin of the left cranial lung lobe; white arrow (solid line): caudal interlobular fissure.
Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
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Bovine Thoracoscopy
Scharner, Dorn, and Brehm
the collapsed lung. We do not know if a higher insufflation pressure would have improved visibility of these structures or if withholding food preoperatively would improve overall intrathoracic observation. CO2 insufflation of the pleural space performed under general anesthesia during thoracoscopy in horses and dogs does improve intrathoracic viewing.15–17 In standing cattle, CO2 insufflation to 5 mmHg did not improve viewing of intrathoracic structures and particularly not in the right cranial thoracic space. One possible explanation might be that the right bovine lung is larger than the left and, therefore, occupies a wide part of the right pleural space despite being collapsed.14 Insufflation to 5 mmHg made endoscopic inspection of the heart and pericardial tissue possible in four cows. In 1cow, the heart was visible on the right side without insufflation, but only when the endoscope was directed between the diaphragm and caudal lung lobe. One limitation of our study is the absence of preoperative thoracic radiographs to rule out the presence of some pathologic findings, like masses, thoracic effusions, inflammatory pulmonary diseases amongst others that could have influenced our results, although other abnormalities like adhesions would likely not be detected. Another limitation was the order of examinations, which was always identical. In our experience with horses, beginning bilateral thoracoscopy on the left side reduces the risk of development of bilateral pneumothorax.8 For this reason, and because we did not know if there might be similar findings in cattle, we decided to begin the procedure on the left side. We did not administer antibiotics despite using the same portal within 24 hours, because these were classified as clean procedures. No postoperative signs of inflammation or infection were observed. Summarily, we found that bovine thoracoscopy can be safely performed on healthy standing cattle without major complications. Because cattle have an intact mediastinum,14 the risk for respiratory problems during thoracoscopy (e.g., bilateral pneumothorax) is considered to be low. Thoracoscopic examination is minimally invasive method and should be considered as a complementary technique to visually explore the intrapleural space, obtain fluid and tissue samples, and to detect and diagnose pulmonary diseases.
REFERENCES 1. Mackey VS, Wheat JD: Endoscopic examination of the equine thorax. Equine Vet J 1985;17:140–142 2. Steiner A: Einsatz bildgebender Verfahren beim Rind. Tierarztl Prax Ausg G Grosstiere Nutztiere 2011;39:275 3. Van Biervliet J, Kraus M, Woodie B, et al: Thoracoscopic pericardiotomy as a palliative treatment in a cow with pericardial lymphoma. J Vet Cardiol 2006;8:69–73 4. Peroni JF, Horner NT, Robinson NE, et al: Equine thoracoscopy: normal anatomy and surgical technique. Equine Vet J 2001;33:231–237 5. Hendrickson DA: Rib resection and pericardiotomy. in Hendrickson DA (ed): Techniques in Large Animal Surgery (ed 3). Ames, IA, Blackwell Publishing, 2007, pp 282–286 6. Ducharme NG, Fubini SL, Rebhun WC, et al: Thoracotomy in adult dairy cattle 14 cases (1979–1991). J Am Vet Med Assoc 1992;200:86–90 7. Walton RS: Video‐assisted thoracoscopy. Vet Clin North Am Small Anim Pract 2001;31:729–759 8. Scharner D: Thorakoskopische Untersuchungen am stehenden sedierten Pferd—Anatomie und Technik. Pferdeheilkunde 2012;28:46–52 9. Raphel CF, Gunson DE: Percutaneous lung biopsy in the horse. Cornell Vet 1981;71:439–448 10. Venner M, Schmidbauer S, Drommer W, et al: Percutaneous lung biopsy in the horse: comparison of two instruments and repeated biopsy in horses with induced acute interstitial pneumopathy. J Vet Intern Med 2006;20:968–973 11. Fair JJ: Anesthesia for thoracoscopy: an overview. AANA J 1994;62:133–138 12. Unzueta MC, Sabaté S, Casas JI, et al: Anesthesia for thoracoscopy. Rev Esp Anestesiol Reanim 1996;43:67–69 13. Dave N, Fernandes S: Anaesthetic implications of paediatric thoracoscopy. J Minim Access Surg 2005;1:8–14 14. Budras K‐D, Wünsche A: Brusthöhle. in Budras K‐D, Wünsche A (eds): Atlas der Anatomie des Rindes. (ed 2). Hannover, Germany, Schlüterche Verlagsgesellschaft, 2002, pp 62–65 15. Vachon AM, Fischer AT: Thoracoscopy in the horse: diagnostic and therapeutic indications in 28 cases. Equine Vet J 1998;30: 467–475
DISCLOSURE
16. Quandt JE: Anesthetic considerations for laser, laparoscopy, and thoracoscopy procedures. Clin Tech Small Anim Pract 1999;14:50–55
The authors report no financial or other conflicts related to this study.
17. Walsh PJ, Remedios AM, Ferguson JF, et al: Thoracoscopic versus open partial pericardectomy in dogs: comparison of postoperative pain and morbidity. Vet Surg 1999;28:472–479
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Veterinary Surgery 43 (2014) 85–90 © Copyright 2013 by The American College of Veterinary Surgeons
