Advances in Minimally Invasive Procedures of the Thoracic Cavity

Significant advances in veterinary minimally invasive surgeries and procedures have occurred in the past 10 years. These advances have been allowed due to continual research into optimizing working space through one-lung ventilation techniques and carbon dioxide insufflation. Additionally, minimally invasive surgery enthusiasts have joined forces with interventionalists and, in many cases, physicians to push the boundaries, minimize pain, suffering, and time away from owners with advances in a variety of procedures. Several larger multi-institutional retrospective studies on various disease processes allow veterinarians and owners to understand that minimally invasive approaches allow for outcomes comparable to traditional open surgery and, in some cases, may now be considered the standard of care in canine and feline patients.

Augmenting Veterinary Minimally Invasive Surgery: Evidence-based Review of Foundational and Novel Devices and Technology

Veterinary minimally invasive surgery continues to grow as a specialty. With increasing experience in this field, comes improved accessibility as well as progressive complexity of procedures performed. Advancement in technology has been both a response to the growth and a necessary driver of continued refinement of this field. Innovative research leading to advancements in surgical equipment has led to the development of novel image acquisition platforms, cannulas, smoke evacuation systems, antifog devices, instrumentation, and ligating/hemostatic devices. These innovations will be reviewed and potential clinical applications are discussed.

Evaluation of long-term outcome after lung lobectomy for canine non-neoplastic pulmonary consolidation via thoracoscopic or thoracoscopic-assisted surgery in 12 dogs

OBJECTIVE

To report outcomes of thoracoscopic (TL) and thoracoscopic-assisted lung lobectomy (TAL) for treatment of non-neoplastic pulmonary consolidation (PC) in dogs.

STUDY DESIGN

Retrospective case series.

ANIMALS

Twelve client-owned dogs.

METHODS

The medical records of 12 dogs that underwent TL or TAL for PC at 3 veterinary institutions between 2011 and 2020 were reviewed. Signalment, history, physical examination, diagnostics, days in hospital, anesthetic and procedure times, intraoperative/postoperative complications, conversion rates, duration of indwelling thoracic drain, and long-term outcomes were recorded.

RESULTS

Nine patients underwent a TL approach and 3 underwent TAL. In those that underwent TL, conversion to an intercostal thoracotomy was performed in 4 out of 9 dogs. Conversion was performed due to adhesions (n = 3) or poor visualization (1). Histopathologic examination was consistent with pneumonia due to an infectious process (n = 10), bronchioalveolar malformation with abnormal cilia (1), and left-sided cardiac insufficiency vs. pulmonary alveolar proteinosis (1). The mean duration of hospital stay was 4 days (range, 1-6 days). Complications occurred postoperatively in 7 dogs and included self-limiting hemorrhage (n = 3), self-resolving pneumothorax (2), incisional dehiscence (1), and severe dyspnea in a brachycephalic breed leading to euthanasia (1). For the 11 dogs that survived the perioperative period, there was no evidence of recurrence with a median follow up of 24 months (range, 5-120 months).

CONCLUSION

Thoracoscopic (TL) and thoracoscopic-assisted lung lobectomy (TAL) is a reasonable surgical approach in select dogs with PC.

CLINICIAL RELEVANCE

Conversion rates were higher than those historically reported for dogs undergoing thoracoscopic lung lobectomy for primary lung tumors.

Complications and outcomes of thoracoscopic-assisted lung lobectomy in dogs

OBJECTIVE

To describe complications and outcomes of dogs undergoing thoracoscopic-assisted (TA) lung lobectomy.

STUDY DESIGN

Multi-institutional, retrospective study.

ANIMALS

Client-owned dogs (n = 30).

METHODS

Medical records of dogs that underwent TA lung lobectomy were reviewed. Signalment, bodyweight, clinical signs, imaging findings, surgical variables, complications, and short-term/long-term outcome were assessed. Thoracoscopic-assisted lung lobectomy was performed with a mini-thoracotomy.

RESULTS

Twelve intraoperative complications were recorded in 11 dogs, 6 requiring conversion to open thoracotomy. Reasons for conversion were reported in 5/6 dogs and included adhesions (2), difficultly manipulating the lesion through the mini-thoracotomy (2), and acute oxygen desaturation (1). One lung ventilation was successful in 4 of the 7 dogs in which this was attempted. A linear stapling device (DST series Medtronic, Minneapolis, Minnesota) was used for lung lobe ligation in 14 dogs. Twenty-three dogs underwent surgery for a neoplastic lesion, with 19 of these being carcinoma. The median lesion size was 4.3 cm (range 1-10 cm); margins were clean, except in 1 dog. Complications were documented in 8 dogs prior to discharge, 5 of these being classified as mild. Twenty-nine dogs were discharged at a median of 47 h postoperatively (range 24-120 h). Death was reported in 9 dogs, with a median survival time of 168 days (range 70-868 days).

CONCLUSION

Thoracoscopic-assisted lung lobectomy was achieved with few major complications in the population reported here. Dogs were able to be discharged from hospital quickly, with most surviving beyond the follow-up period.

CLINICAL SIGNIFICANCE

Thoracoscopic-assisted lung lobectomy may be considered to facilitate the excision of larger pulmonary lesions or to treat smaller dogs, in which a thoracoscopic excision may be technically more challenging.

Thoracoscopic treatment of persistent right aortic arch in dogs with and without one lung ventilation

OBJECTIVE

To evaluate thoracoscopic treatment of persistent right aortic arch (PRAA) in dogs with and without the use of one lung ventilation (OLV).

STUDY DESIGN

Retrospective cohort study.

ANIMALS

Twenty-two (client-owned and shelter) dogs diagnosed with PRAA.

METHODS

Medical records were reviewed retrospectively and intraoperative and immediate postoperative data were compared between dogs that underwent thoracoscopic treatment of PRAA with (OLV+) and without (OLV-) OLV.

RESULTS

Ten of the 12 dogs in the OLV+ group and 7/10 dogs in the OLV- group had their left ligamentum arteriosum successfully ligated during thoracoscopy. Median surgical time, surgery complications, anesthesia complications, and rate of conversion to an open thoracotomy due to limited visualization or surgical complications were similar between the two groups.

CONCLUSION

Thoracoscopic treatment of PRAA can be performed with or without OLV. Surgical time, intraoperative complications, and conversion rates were similar between dogs that underwent thoracoscopic treatment of PRAA with and without OLV. OLV may not have contributed to improved visualization in this group of dogs.

CLINICAL SIGNIFICANCE (OR IMPACT)

The use of OLV is safe during thoracoscopic treatment of PRAA. OLV did not appear to provide significant benefits in this case series and thoracoscopic treatment of PRAA in dogs may be performed successfully with or without the use of OLV.

Surgical management and outcome of dogs with primary spontaneous pneumothorax: 110 cases (2009-2019)

OBJECTIVE

To describe surgical management and associated outcomes for dogs with primary spontaneous pneumothorax.

ANIMALS

110 client-owned dogs with primary spontaneous pneumothorax that underwent surgical management.

PROCEDURES

Medical records at 7 veterinary teaching hospitals were reviewed. Data collected included signalment, history, clinical signs, radiographic and CT findings, surgical methods, intraoperative and postoperative complications, outcomes, and histopathologic findings. Follow-up information was obtained by contacting the referring veterinarian or owner.

RESULTS

110 dogs were included, with a median follow-up time of 508 days (range, 3 to 2,377 days). Ninety-nine (90%) dogs underwent median sternotomy, 9 (8%) underwent intercostal thoracotomy, and 2 (2%) underwent thoracoscopy as the sole intervention. Bullous lesions were most commonly found in the left cranial lung lobe (51/156 [33%] lesions) and right cranial lung lobe (37/156 [24%] lesions). Of the 100 dogs followed up for > 30 days, 13 (13%) had a recurrence of pneumothorax, with median time between surgery and recurrence of 9 days. Recurrence was significantly more likely to occur ≤ 30 days after surgery, compared with > 30 days after surgery. Recurrence > 30 days after surgery was rare (3 [3%]). No risk factors for recurrence were identified.

CONCLUSIONS AND CLINICAL RELEVANCE

Lung lobectomy via median sternotomy resulted in resolution of pneumothorax in most dogs with primary spontaneous pneumothorax. Recurrence of pneumothorax was most common in the immediate postoperative period, which may have reflected failure to identify lesions during the initial thoracic exploration, rather than development of additional bullae.

Resorbable self-locking device for canine lung lobectomy: A clinical and experimental study

OBJECTIVE

To test the feasibility of a resorbable self-locking device for sealing of lung tissue in lung lobectomy in experimental dogs and dogs with pulmonary mass, and to study its resorption with CT.

STUDY DESIGN

Experimental study and clinical case series.

ANIMALS

Five beagles in the experimental group; six canine patients with a pulmonary mass in the clinical group.

METHODS

In both groups, an intercostal incision into thorax was performed. A resorbable self-locking device, LigaTie, was applied at the hilum of left cranial lobe in the experimental group and the affected lobe in the clinical group. Each lobe was removed by cutting the tissue just distal to the device. Video-assisted thoracic surgery was used in the experimental group; postoperative diagnostic imaging was repeated monthly until the device was not apparent on CT.

RESULTS

Application of LigaTie was feasible for lung lobectomy in all dogs. The device enabled en bloc ligation of the hilum of the affected lobe including the pulmonary arteries and veins and lobular bronchus. No air leakage from the resection stump was observed in any dog. Trace of the device on CT images gradually decreased and was undetectable at 4 months postoperatively in experimental dogs.

CONCLUSION

This study suggested that the resorbable self-locking device may be used for sealing of airways in complete lung lobectomy.

CLINICAL RELEVANCE

The resorbable self-locking device is suggested to be useful for canine lung lobectomy and may facilitate thoracoscopic lung lobectomy. Further investigations on its clinical application in small animal surgery are warranted.

Cadaveric evaluation of fluoroscopy-assisted placement of one-lung ventilation devices for video-assisted thoracoscopic surgery in dogs

OBJECTIVE

To evaluate the feasibility of fluoroscopy-assisted placement of one-lung ventilation (OLV) devices in dogs.

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Canine cadavers (n = 8) weighing between 20.2 and 37.4 kg.

METHODS

Thoracoscopic access with a two-port approach was established to evaluate bilateral lung ventilation patterns. Advancement of a left-sided Robertshaw double-lumen endobronchial tube (DLT) and the EZ-blocker (EZ) were evaluated under direct fluoroscopic guidance. Each dog also underwent bronchoscopy-assisted placement of an Arndt endobronchial blocker (EBB). Time to initial placement, success of creating complete OLV (after initial placement attempt and after up to two repositionings), and ease of placement score were recorded. Device position was evaluated bronchoscopically after each fluoroscopy-assisted placement attempt.

RESULTS

Time to initial placement was significantly shorter for EZ than for DLT and EBB. The rate of successful placement after up to two repositioning attempts was 87.5%, 87.5%, and 100.0% on the right and 87.5%, 100.0%, 100.0% on the left for DLT, EZ, and EBB, respectively, and was not different between devices. Ease of placement scores were significantly higher for DLT compared with EZ and EBB on both the left and the right sides.

CONCLUSION

Fluoroscopy-assisted placement of DLT and EZ appears feasible in canine cadavers. EZ-blocker placement was efficient and technically easier than DLT, but positioning must be adapted for dogs. Bronchoscopy-assisted placement of EBB remains highly successful.

CLINICAL SIGNIFICANCE

Fluoroscopy-assisted placement of EZ and DLT is a useful alternative to bronchoscopy-assisted placement of these OLV devices.

Video-assisted thoracic surgery anatomical lobectomy for a primary lung tumor in a dog

A female Bernese Mountain Dog was diagnosed with a right middle lung lobe mass. The dog was positioned in a left lateral recumbency and one-lung ventilation was used under general anesthesia. Video-assisted thoracic surgery anatomical lobectomy was performed with 4 cm small thoracotomy and two 6-mm ports. Pulmonary vessels and bronchus were dissected and isolated individually at the hilum of the right middle lung lobe. Pulmonary vessels were ligated and were coagulated and transected using a vessel sealing device. The bronchus was ligated and transected. The mass in the right middle lung lobe was removed with a clean margin and without complications. Video-assisted thoracic surgery anatomical lobectomy was used to successfully remove a primary lung tumor in a dog.

Use of Minimally Invasive Surgery in the Diagnosis and Treatment of Cancer in Dogs and Cats

Surgical management of neoplastic disease is common in veterinary medicine. Minimally invasive surgery (MIS) has gained widespread acceptance by veterinary surgeons and is experiencing rapid growth and frequency of use. Many neoplastic diseases in the abdomen and thorax of dogs and cats can be treated as effectively with MIS as with traditional open surgery. Additionally, MIS allows for less invasive options for organ biopsy in cancer patients either for initial diagnosis or for staging to inform prognosis and treatment. Despite the recent increase in MIS, additional research is required to further characterize the benefits to oncology patients and to ensure that surgical oncologic principles and patient outcomes are not compromised by the use of MIS.

Optimization of surgical approach for thoracoscopic-assisted pulmonary surgery in dogs

OBJECTIVE

To determine the optimal intercostal space (ICS) to perform thoracoscopic-assisted lung lobectomy.

STUDY DESIGN

Cadaveric study.

ANIMALS

Six mature, medium-sized canine cadavers.

METHODS

Cadavers were placed in right or left lateral recumbency. A 15-mm thoracoscopic cannula was inserted in the middle third of the 9th or 10th ICS. A wound retraction device was placed into a 7-cm minithoracotomy incision created in the middle third of the 4th-7th ICS on the left side and the 4th-8th ICS on the right side. The pulmonary ligaments were sectioned by using a combined intracorporeal and extracorporeal technique. Each lung lobe was sequentially withdrawn from the wound retraction device at the respective ICS and side. A thoracoabdominal stapler was positioned to simulate lung lobectomy, and the distance from the stapler anvil to the hilus was measured.

RESULTS

Simulated thoracoscopic-assisted lung lobectomy performed at left or right ICS 4 and 5, compared with other ICS evaluated, resulted in a significantly shorter median distance from the stapler anvil to the pulmonary hilus of the left cranial and caudal lung lobes and right cranial and middle lung lobes, respectively (all P < .05). Lobectomy at right ICS 5 or 6 resulted in a significantly shorter median distance from the stapler anvil to the pulmonary hilus of the right caudal and accessory lung lobes, respectively (both P < .05).

CONCLUSION

These data may inform minithoracotomy positioning to optimize tumor margin excision during thoracoscopic-assisted lung lobectomy for treatment of pulmonary neoplasia in dogs.

CLINICAL SIGNIFICANCE

Complete lung lobectomy is possible by using the described thoracoscopic-assisted technique in normal, cadaveric lungs.

Video-assisted thoracic surgery for the management of pyothorax in dogs: 14 cases

OBJECTIVE

To report the perioperative findings and outcome of dogs undergoing video-assisted thoracic surgery (VATS) for the management of pyothorax.

DESIGN

Multi-institutional, retrospective study.

ANIMALS

Client-owned dogs (n = 14).

METHODS

Medical records of dogs with pyothorax managed via VATS were reviewed for signalment, history, clinical signs, clinicopathological findings, diagnostic imaging results, surgical variables, bacterial culture and sensitivity results, post-operative management and outcome. VATS was performed after placing a paraxyphoid endoscopic portal and 2-3 intercostal instrument portals. VATS exploration was followed by one or more of the following: mediastinal debridement, tissue sampling, pleural lavage, and placement of a thoracostomy tube.

RESULTS

Two dogs (14%) required conversion from VATS to an open thoracotomy to completely resect proliferative mediastinal tissue. These dogs had severe pleural effusion on preoperative thoracic radiographs and one had severely thickened contrast-enhancing mediastinum on preoperative computed tomography (CT). The cause of pyothorax was identified as a penetrating gastric foreign body (n = 2), migrating plant material (n = 2), and idiopathic (n = 10). The median follow-up time was 143 days (range, 14-2402 days). All dogs were discharged from the hospital and their clinical signs resolved. One patient had recurrence of a pyothorax requiring revision surgery 17 months postoperatively.

CONCLUSION

VATS allows minimally invasive treatment of uncomplicated canine pyothorax. Preoperative thoracic CT may help identify candidates for VATS among dogs with pyothorax.

Treatment of a giant pulmonary emphysematous cyst with primary bronchoalveolar papillary carcinoma in a Shih Tzu dog

OBJECTIVE

To report the surgical treatment of a pulmonary emphysematous cyst concurrent with primary pulmonary bronchoalveolar papillary carcinoma in a dog.

STUDY DESIGN

Clinical case report.

ANIMALS

12-year-old 6.4 kg spayed female Shih Tzu dog.

METHODS

The dog presented for surgical treatment of pulmonary emphysema. Radiography revealed that more than half of the left caudal lung lobe was enlarged and hyperlucent and computed tomography (CT) confirmed the presence of an emphysematous space. Thoracoscopic lung lobectomy was attempted but was converted to an intercostal thoracotomy due to poor visualization and pleural adhesions. A left caudal total lung lobectomy was performed using a self-cutting endoscopic stapler.

RESULTS

The dog recovered uneventfully and a postoperative histopathologic diagnosis of pulmonary cystic bronchoalveolar papillary carcinoma was made. Re-evaluation using a CT scan with contrast study on postoperative days 27 and 177 revealed no evidence of residual, metastatic, or recurrent lesions. The dog has been doing well since surgery during the 11 month follow-up period.

CONCLUSION

This case report suggests a potential relationship between pulmonary emphysematous diseases and primary lung tumors in dogs.

Comparison of acute phase reaction and postoperative stress in pigs undergoing video-assisted thoracoscopic versus thoracotomy pneumonectomy

Background

Video-assisted thoracoscopic surgery (VATS) has been used for many thoracic diseases as an alternate approach to thoracotomy. The aim of this study was to compare the surgical outcome of pneumonectomy using VATS with that using thoracotomy pneumonectomy in pigs. Fourteen pigs were equally divided into two groups; one group underwent VATS and the other group underwent transthoracic pneumonectomy. We monitored pre-, intra-, and post-operative physiologic parameters, along with blood cell count, serum C-reactive protein (CRP), serum amyloid A (SAA), interleukin-6 (IL-6) and cortisol. The differences between the two approaches were analyzed.

Results

Mean surgical time in the VATS group (160.6 ± 16.2 min) was significantly longer than that in the thoracotomy group (123.7 ± 13.2 min). In both groups, CRP and IL-6 concentrations were significantly increased at postoperative 4 h, and then gradually decreased to preoperative levels. CRP and IL-6 at postoperative day 1 were significant lower in the VATS group compared with the thoracotomy group. SAA was significantly increased at postoperative days 1 and 3 in both groups compared with preoperative levels. Cortisol was significantly increased immediately after surgery in both groups compared with preoperative levels, and was significantly higher in the thoracotomy group than the VATS group at postoperative 4 h and 1 day.

Conclusions

There was no difference between the two groups in physiologic parameters and blood cell count. However, the results indicate that VATS resulted in a smaller incision, less acute-phase reaction, less stress and less pain compared with thoracotomy pneumonectomy.

Complications and Conversion from Endoscopic to Open Surgery

Endoscopic surgery is a rapidly expanding modality of diagnosis and treatment of small animal patients. The development of skills, equipment, and minimally invasive means of correcting complications may be of great importance in decreasing the incidence of conversion from endoscopic to open surgery; however, conversion to an open approach should never be seen as a failure. Conversion should be considered at any time that it is of the greatest benefit for the patient. This concept is important enough to warrant discussion with the owner before surgery and acceptance of the need to convert without further consultation during the procedure.

Current concepts in minimally invasive surgery of the thorax

Thoracoscopy is a technique that has been shown to decrease patient morbidity and is rapidly becoming more diversely applied for diagnostic and therapeutic interventions in veterinary medicine. This article describes the basic equipment and application of thoracoscopy in small animal surgery. The diagnostic and therapeutic applications are introduced and briefly described.

Evaluation of Video-Assisted Thoracic Surgery for Treatment of Spontaneous Pneumothorax and Pulmonary Bullae in Dogs

OBJECTIVE

To describe the operative findings and clinical outcome in dogs undergoing video-assisted thoracic surgery (VATS) for treatment of spontaneous pneumothorax and pulmonary bullae.

STUDY DESIGN

Multi-institutional retrospective case series.

ANIMALS

Dogs (n = 12) with spontaneous pneumothorax and/or pulmonary bullae.

METHODS

Medical records (2008-2013) were reviewed for signalment, clinical signs, diagnostic imaging, surgical and histopathologic findings, and outcome in 12 dogs that had VATS for treatment of spontaneous pneumothorax and pulmonary bullae. In particular, conversion to median sternotomy and surgical success were evaluated.

RESULTS

Twelve dogs had initial VATS for spontaneous pneumothorax and/or pulmonary bullae. Conversion to median sternotomy because of inability to identify a parenchymal lesion/leak was necessary in 7 (58%) dogs. VATS without conversion to median sternotomy was performed in 6 (50%) dogs. Successful surgical outcomes occurred in 5 (83%) dogs that had conversion to median sternotomy, and in 3 (50%) dogs that had VATS without conversion to median sternotomy.

CONCLUSIONS

Exploratory thoracoscopy was associated with a high rate of conversion to median sternotomy because of inability to identify leaking pulmonary lesions in dogs with spontaneous pneumothorax and pulmonary bullae. Failure to convert to a median sternotomy may be associated with recurrent or persistent pneumothorax.

Role of surgery in multimodal cancer therapy for small animals

Surgery is a critical component in the treatment of most solid tumors in small animals. Surgery is increasingly combined with adjuvant therapies such as chemotherapy and radiation so surgeons who are treating cancer must have a good understanding of surgical oncology principles, cancer biology, and the roles and potential interactions of surgery, radiation, and chemotherapy. The sequencing plan for these modalities should be determined before treatment is initiated. The surgical oncologist must have a working knowledge of chemotherapy agents and radiation and the effect of these treatments on the ability of tissues to heal and the outcome for the patient.