Video-Assisted Thoracoscopic Extirpation of the Tracheobronchial Lymph Nodes in Dogs

Evaluation of mediastinoscopy for cranial mediastinal and tracheobronchial lymphadenectomy in canine cadavers

OBJECTIVE

To report technical feasibility and describe procedural details of a novel single incision minimally invasive approach to the mediastinum in cadaver dogs.

STUDY DESIGN

Cadaveric study.

ANIMALS

Large breed (25-40 kg) cadaver dogs (n = 10).

METHODS

Three of 10 cadavers were used for preliminary technique development without data recording. Cadaver specimens underwent pre- and postoperative thoracic computed tomographic scans. Seven dogs were placed in dorsal recumbency and mediastinoscopy was performed via a SILS port placed cranial to the thoracic inlet with CO2 insufflation of the mediastinum at 2-4 mmHg. Retrieval of all CT and visually identified mediastinal lymph nodes (LN) was attempted; endoscopic compartmental and individual LN dissection times and subjective operative challenges were recorded. Procedural success scores for visualization and dissection as well as NASA-task force index scores were recorded per lymph node, per cadaver.

RESULTS

Median time required for initial approach including SILS placement was 5 min (range 5-10 min). Individual LN retrieval times ranged from 2 to 32 min. Mediastinoscopic retrieval of LNs was most commonly successful for the left tracheobronchial LN (7/7), followed by the right tracheobronchial LN (4/7), the left and right sternal LNs (3/7 each), and the cranial mediastinal LNs (1/7). Post-procedure pleural gas was identified on CT in 4/7 cadavers.

CONCLUSIONS

Mediastinoscopy as reported was feasible in large breed canine cadavers and retrieval or cup biopsy of a variety of lymph nodes is possible from the described approach. Application in living animals and its associated challenges should be further investigated.

CLINICAL SIGNIFICANCE

Mediastinoscopy may provide a novel minimally invasive approach to the evaluation and oncologic staging of the cranial mediastinum in dogs.

Nonselective Lymph Node Dissection and Sentinel Lymph Node Mapping and Biopsy

Clinical staging is important for determining the extent of disease in animals with malignant cancers. The status of the lymph node will help determine whether adjuvant treatment is indicated. Historically, the regional anatomic lymph node has been sampled to determine the presence or absence of metastatic disease, but there is increasing evidence that the regional anatomic lymph node is often different to the sentinel lymph node. As a result, several sentinel lymph node mapping techniques have been described for more accurate clinical staging of oncologic patients.

Use of a novel vessel-sealing device for peripheral lung biopsy and lung lobectomy in a cadaveric model

OBJECTIVE

To evaluate the Caiman vessel-sealing device for peripheral lung biopsy and total lung lobectomy in cadaveric canine lung lobes.

MATERIAL AND METHODS

Twelve lung lobes were randomly assigned to peripheral lung biopsy (n=6) or total lung lobectomy (n=6) with the 12-mm Caiman vessel-sealing device. Lungs were connected to a ventilator set at 10 breaths per minute with an initial pressure of 5 cm H₂ O during the procedure. The lungs were submerged in water for leak testing and the pressure increased until leakage occurred.

RESULTS

Mean airway pressure at which leakage occurred was 39.17 ±13.20 cm H₂ O for peripheral lung biopsies and 38.33 ±13.67 cm H₂ O for total lung lobectomies. None of the samples leaked below 25 cm H₂ O, which is well above the physiologic airway pressure. Histologically, the largest bronchial diameter at the sealed area was 8.84 mm and the extent of collateral damage was approximately 2.7 mm in all specimens.

CLINICAL SIGNIFICANCE

The Caiman vessel-sealing device was successfully used for peripheral lung biopsy and total lung lobectomy in cadaveric canine lung lobes. All sealed lung lobes tolerated supra-physiologic airway pressure, displayed minimal collateral damage, and were of good diagnostic quality. Further experimental studies are needed to evaluate the clinical safety of the device for peripheral lung biopsy or total lung lobectomy.

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.

Use of a custom-made limb-press model to assess intra- and extracapsular techniques for treating cranial cruciate ligament rupture in cats

Objectives This study aimed to compare the under-and-over technique, a type of intracapsular treatment, and the standard fabella-tibial suture, a method for extracapsular treatment, in achieving immediate, postoperative stifle stability after cranial cruciate ligament (CrCL) rupture by using a feline, custom-made limb-press model. Methods Cadaveric feline hindlimb specimens (n = 14) were positioned in the limb press at predefined joint angles (stifle joint: 120°; hock joint: 120°), and vertical loads of 5%, 10%, 20% and 30% body weight were applied statically. Mediolateral radiographic views were obtained of the stifles under each load before and after CrCL transection, as well as after treatment with either of the two surgical techniques, and differences in distance between two predefined radiographic points for each radiograph were analysed. Results The general linear model showed a significant effect of load ( P <0.01) and technique ( P = 0.004) and a significant interaction between load and technique ( P = 0.006) regarding craniocaudal stifle stability. Distances between predefined tibial and femoral reference points were consistently higher in transected CrCLs than in intact stifles. All standard fabella-tibial suture-treated stifles (n = 7) were stable at all loads tested. Of the seven under-and-over technique-treated stifles, one was unstable at 20% body weight load and three at 30% body weight load. Conclusions and relevance Our model, which appropriately reproduced certain aspects of domestic shorthair cat stifle mechanics, indicated that a 40 lb monofilament nylon prosthesis, tightened at 20 N, produces more favourable biomechanical stabilisation of craniocaudal cruciate-related stifle instability than a 0.5 cm wide strip of fascia lata applied intracapsularly.

Bilateral medial iliac lymph node excision by a ventral laparoscopic approach: technique description

The aim of this study was to describe a ventral laparoscopic technique for bilateral medial iliac lymphadenectomy in dogs. Twelve intact male purpose-bred research dogs, weighing less than 15 kg, were positioned in dorsal recumbency, and a 3-portal technique was used. Bilateral dissection was performed with vessel-sealing devices while tilting the surgical table by up to 30° towards the contralateral side of the target medial iliac lymph node (MILN) without changing the surgeon’s position. Using a ventral laparoscopic approach, bilateral MILNs were identified and excised in all dogs. The mean times for unilateral and bilateral MILN dissections were 9.7 ± 3.8 and 21.0 ± 6.0 min, respectively. The mean times for the right and left MILN dissections were 10.8 ± 4.3 and 9.8 ± 2.5 min, respectively. The mean total surgery time was 43.7 ± 7.7 min. In total, 26 MILNs were dissected. Several complications, including mild to moderate capillary hemorrhage from perinodal fat and vessels (controlled laparoscopically), mild spleen trauma caused by the first trocar insertion and capsular damage of MILNs, were observed. However, there were no other major complications. All MILN samples were evaluated and deemed suitable for histopathologic diagnosis. Laparoscopic excision of MILNs is a useful method of excisional biopsy for histopathologic diagnosis. Using this ventral laparoscopic approach with the 3-portal technique, bilateral MILN dissection suitable for obtaining histopathologic samples could be achieved in a short time in dogs weighing less than 15 kg.

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.