Laparoscopic access to the liver and application of laparoscopic microwave ablation in 2 dogs with liver neoplasia

Evaluation of sternal recumbency for laparoscopic right lateral liver lobectomy through a transdiaphragmatic port in a canine cadaveric population

OBJECTIVE

To evaluate the feasibility of laparoscopic right lateral liver lobectomy in canine cadavers positioned in sternal recumbency with the aid of an intrathoracic transdiaphragmatic trocar (ITT).

STUDY DESIGN

Ex vivo cadaveric study.

SAMPLE POPULATION

Thirteen canine cadavers.

METHODS

All cadavers underwent laparoscopic right lateral liver lobectomy in sternal recumbency with ITT placement using either laparoscopic stapling or suture loop equipment. Body weight, total surgical time, liver lobectomy time, and surgical complications were documented. After all liver lobectomies, the livers were harvested, and the weight of the liver lobes and distance to the hilus were recorded.

RESULTS

All liver lobectomies were completed successfully, with two ports placed on the right lateral abdomen and one ITT port. Median total surgical time was 35.5 min (range, 25.1-62.8), median liver lobectomy time was 18.5 min (range, 6.5-42.9), and three cases experienced loss of insufflation due to ITT port failure. A moderate correlation between the weight of the right liver lobe and a longer liver lobectomy time (rs = .73, p = .0042) was found.

CONCLUSION

All right lateral liver lobectomies could be performed in sternal recumbency with the placement of an ITT, regardless of body weight. The ITT was useful in all cases for visualization of the hilus.

CLINICAL SIGNIFICANCE

Laparoscopic right lateral liver lobectomy is feasible in normal canine patients with no hepatic neoplasia or obvious pathology of different sizes in sternal recumbency. The use of a transdiaphragmatic port can help to evaluate proximity to the hilus and manipulation of the liver lobes.

Laparoscopic ultrasound-guided microwave ablation of hepatocellular carcinoma in a dog

OBJECTIVE

The aim of the study was to describe laparoscopic ultrasound (LUS) to guide microwave ablation (MWA) of hepatocellular carcinoma (HCC) in a dog.

ANIMALS

A 13-year-old female spayed Husky.

STUDY DESIGN

Case report.

METHODS

The dog was referred for laparoscopic MWA of a caudate lobe HCC measuring 2.7 cm × 1.9 cm× 2.3 cm. Laparoscopic ultrasound was used to guide percutaneous placement of a MWA probe within the caudate lobe mass. LUS was used to determine the tumor margins for placement of the probe within the medial and lateral aspects as well as the center of the mass. Additionally, LUS allowed visualization of vessels within the tumor so they could be avoided during probe placement.

RESULTS

Safe ablation was accomplished, and the dog recovered uneventfully with no complications. Follow-up computed tomography (CT) 3- and 12-months postoperatively revealed complete ablation of the caudate lobe mass. However, progressive increase in size of the right medial lobe mass occurred. Right medial liver lobectomy was performed 13 months after MWA, with a histopathologic diagnosis of HCC. The dog was euthanized 777 days post MWA and 1445 days post initial left lateral lobectomy for HCC.

CONCLUSION

Laparoscopic ultrasound was useful in guiding complete and safe MWA of an HCC in this dog. Laparoscopic ultrasound should be considered when performing laparoscopic MWA of liver lesions in dogs.

Veterinary Interventional Oncology

Interventional oncology (IO) is a rapidly growing field in veterinary medicine and has been accepted as a fourth pillar of treatment of neoplastic disease with other modalities including surgery, chemotherapy, and radiation therapy. The major categories of IO therapies in companion animals are focused on the use of locoregional therapies and stenting of malignant obstructions. Although significant assessment of veterinary IO techniques is still necessary, early evaluation of these varying techniques is demonstrating promising results.

Microwave ablation for the control of bleeding from disintegrated mammary tumours in two dogs

A 16-year-old intact female Miniature Dachshund (dog 1) and a 13-year-old intact female American Cocker Spaniel (dog 2) presented with a chief complaint of bleeding from a mammary gland tumour ulceration. Dog 1 was transferred to hospital from a local hospital in a haemorrhagic shock state with uncontrolled continuous bleeding. Thoracic radiographs revealed multiple nodular shadows suspected to be pulmonary metastasis. Dog 2 presented with intermittent bleeding from a mass lesion in the right fifth mammary gland. Due to high anaesthetic risk secondary to severe mitral valve insufficiency (ASA status III), the owner declined surgical excision of the tumour. Therefore, microwave ablation (MWA) under local anaesthesia was chosen in order to achieve adequate haemostasis. Both dogs received local anaesthesia around the bleeding mass lesion, and the disintegrated site was microwave-ablated; dog 1 underwent MWA after blood transfusion to improve the haemorrhagic shock. The ablation site was protected using a non-adhesive dressing. Scarring of the ulcerated site led to complete haemostasis in both cases. Dog 1 underwent tumorectomy on the 31st hospital day to prevent rebleeding; histopathology results were consistent with mammary adenocarcinoma with the ablation site covered by a capsule structure. To the authors' knowledge, this is the first case report describing the use of MWA to stop bleeding from mammary tumours in veterinary medicine. MWA is a feasible and potentially effective palliative treatment modality to stop bleeding from disintegrated mammary tumours in dogs under local anaesthesia.

Percutaneous ultrasound-guided microwave ablation for treatment of hepatocellular carcinomas in dogs: four cases (2019-2020)

OBJECTIVES

To describe ultrasound-guided microwave ablation as a minimally invasive treatment option for primary or metastatic hepatocellular carcinomas.

METHODS

Four client-owned dogs underwent percutaneous ultrasound-guided microwave ablation of three primary and one metastatic hepatocellular carcinoma, diagnosed on cytology/histopathology. In each case, multiple ultrasound-guided thermal lesions were created in a 10 to 40 minutes ablation at 30 to 35 W. Real-time monitoring was performed using 10 MHz diagnostic ultrasound transducers. The procedures were performed without complication and CT scans or abdominal ultrasounds were repeated immediately after. Patients were discharged on oral analgesia on the same day or 24 hours later.

RESULTS

Hepatocellular carcinomas were successfully ablated, which in some cases resulted in an improvement in clinical signs and laboratory values. The patients were followed up for a time ranging between 39 and 649 days and no evidence of disease progression was found. Three out of four patients are still alive at the time of writing.

CLINICAL SIGNIFICANCE

In these four patients, minimally invasive ultrasound-guided microwave ablation was feasible and resulted in no immediate complications. Regular imaging follow-up is recommended after the procedure and further studies on microwave ablation are warranted to establish its effectiveness in dogs with hepatocellular carcinomas.

Risk factors and outcome in dogs with recurrent massive hepatocellular carcinoma: a Veterinary Society of Surgical Oncology case-control study

Local recurrence after surgical excision of canine massive hepatocellular carcinoma (HCC) has been poorly studied in veterinary medicine with scant information published regarding risk factors for and outcome following recurrence. The aim of this case-control study was to describe the time to recurrence, evaluate potential risk factors for recurrence, and report the outcome in dogs with massive HCC. Medical records for 75 dogs who developed recurrence and 113 dogs who did not develop recurrence were reviewed. Statistical analyses were performed to determine risk factors for recurrence as well as the median time to develop recurrence and overall survival time (OS). None of the risk factors evaluated were significant for the development of recurrence. The median time to develop recurrence was 367 days (range: 32-2096 days). There was no significant difference in median OS for dogs who developed recurrence vs. those who did not (851 vs. 970 days). For dogs with recurrent HCC, treatment at recurrence trended toward prolonged OS but was not significantly different from dogs not undergoing treatment at recurrence. There was no significant difference in median OS for dogs with histologically complete vs. incomplete tumor excision (990 vs. 903 days). Though specific risk factors for recurrence were not identified, elevations in liver values were noted in patients with recurrent disease and could act as a noninvasive surveillance tool. Recurrence was noted earlier in dogs who had routine post-operative surveillance (228 vs. 367 days). Routine surveillance for recurrence is recommended especially in dogs where further intervention is possible and should extend beyond 1 year. Patients with massive HCC have a good long-term prognosis regardless of incomplete excision, pulmonary metastasis, or recurrent local disease. This article is protected by copyright. All rights reserved.

Use of percutaneous microwave ablation in the treatment of retroperitoneal neoplasia in three dogs

CASE DESCRIPTION

3 dogs with retroperitoneal masses (2 renal and 1 located near the diaphragm) were treated by percutaneous microwave ablation (MWA).

CLINICAL FINDINGS

Dogs between 11 and 13 years of age weighing between 13.7 and 43.8 kg had either a renal mass (n = 2) or a mass located in the caudodorsal aspect of the retroperitoneal space near the right side of the diaphragm (1). Cytology revealed that one of the renal masses and the mass located near the diaphragm were malignant neoplasias. Findings on cytologic evaluation of a sample of the other renal mass was nondiagnostic. Maximum mass diameters ranged between 1.4 and 2.5 cm.

TREATMENT AND OUTCOME

All dogs were treated by percutaneous MWA. Probes were directed into tumors by use of ultrasound and CT guidance, and microwave energy was applied to each mass. Findings on imaging of each mass following MWA was consistent with successful treatment. No intraprocedural or major postprocedural complications occurred, and all dogs were discharged from the hospital within 3 days of treatment. Two dogs died at 3 and 21 months after MWA with no known local recurrence; 1 dog was still alive 64 months after treatment.

CLINICAL RELEVANCE

Although the indications for MWA in the treatment of neoplasia in companion animals are limited, the outcomes of dogs in the present report provided preliminary evidence that percutaneous MWA can be safely used to effectively treat retroperitoneal neoplasia. This procedure was successfully performed with image guidance in all 3 dogs.

Investigation of the use of microwave ablation with and without cooling urethral perfusion for thermal ablation of the prostate gland in canine cadavers

OBJECTIVE

To investigate the use of microwave ablation (MWA) with cooling urethral perfusion and with no perfusion (MWA-UP and MWA-NP, respectively) for prostate gland ablation in canine cadavers.

ANIMALS

Cadavers of 18 sexually intact male dogs.

PROCEDURES

After technique refinement in 2 cadavers, laparotomy with ultrasound-guided MWA-UP (n = 8) or MWA-NP (8) of the prostate gland was performed in 16 cadavers. Normograde cystourethroscopy was performed before and after treatment; recorded images were reviewed in a blinded manner for scoring of urethral mucosal discoloration and loss of integrity. Difficulty with cystoscope insertion was recorded if present. Excised prostate glands were fixed for serial sectioning, gross measurements, and calculation of percentage ablation. Percentages of prostate tissue necrosis from MWA, denuded urethral mucosa, and depth of epithelial surface loss in an adjacent section of the colon were estimated histologically. Variables of interest were statistically analyzed.

RESULTS

Difficulty with cystoscope insertion after treatment was significantly more common and scores for urethral mucosal discoloration and loss of integrity were significantly higher (indicating more severe lesions) for the MWA-NP group than for the MWA-UP group. The histologically assessed percentage of denuded urethral mucosa was also greater for the MWA-NP group. Overall median percentage prostate gland ablation was 73%; this result was not associated with prostate gland volume or chronological order of treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

MWA-UP induced subtotal thermal necrosis of prostate glands in canine cadavers while limiting urethral mucosal injury. Further study is required to optimize the technique and evaluate its safety and efficacy in vivo as a future curative-intent treatment for prostatic tumors in dogs.

Feasibility of laparoscopic liver lobectomy in dogs

OBJECTIVE

To determine the feasibility of laparoscopic liver lobectomy (LLL) in dogs by using canine cadavers and to describe the clinical application in dogs with liver disease.

STUDY DESIGN

Ex vivo experiment and descriptive case series.

SAMPLE POPULATION

Twelve canine cadavers and six client-owned dogs.

METHODS

Cadavers underwent LLL with an endoscopic stapler. The percentage of liver lobe resected was determined by volume. The distance from the staple line to hilus was measured. Medical records of dogs undergoing LLL were reviewed.

RESULTS

In cadavers ≤15 kg, left lateral lobectomy completeness was 87.3% (84.6%-96.6%), and remaining median (interquartile range) hilar length was 1 cm (0.25-1.75). Left medial lobectomy completeness was 72.5% (66.7%-80%), and remaining hilar length was 1.6 cm (0.47-1.75). Central division resection completeness was 68.3% (60%-92.9%), and remaining hilar length was 2.7 cm (0.8-5). Laparoscopic liver lobectomy was not feasible for right division lobes and in cadavers >15 kg. Five dogs with peripheral quadrate or left lateral lobe masses underwent stapled, partial laparoscopic lobectomy (30%-90%). One dog underwent stapled, left lateral lobectomy (90%) after open procedure conversion. Histopathological diagnoses included hepatocellular carcinoma (3), nodular hyperplasia (1), biliary cyst adenoma (1), and fibrosis (1).

CONCLUSION

Laparoscopic liver lobectomy of the left and central divisions is feasible in cadavers ≤15 kg with an endoscopic stapler. Partial LLL of the left and central divisions is feasible in select dogs with liver disease.

CLINICAL SIGNIFICANCE

Laparoscopic liver lobectomy may be a viable alternative to laparotomy in small-to-medium size dogs with peripheral liver masses of the left and central divisions.

Percutaneous microwave ablation of solitary presumptive pulmonary metastases in two dogs with appendicular osteosarcoma

OBJECTIVE

To describe percutaneous microwave ablation (MWA) of presumptive pulmonary metastases and the outcome of two dogs.

ANIMALS

Two dogs with pulmonary lesions after treatment of spontaneously occurring appendicular osteosarcoma.

STUDY DESIGN

Preliminary prospective clinical study.

METHODS

Two large-breed dogs were referred from tertiary veterinary hospitals 146 and 217 days after limb amputation to pursue MWA as an alternative therapy to metastasectomy. Both dogs had been receiving chemotherapy protocols at their respective referral centers.

RESULTS

A novel percutaneous approach for MWA with ultrasonographic or computed tomographic (CT) guidance was successfully performed. The only complications consisted of pneumothoraxes, requiring treatment in one dog. In the weeks after their procedures, both dogs were reported to do well at home. Dog 1 died and dog 2 was euthanized 82 and 19 days, respectively, after their MWA of confirmed (dog 1) or presumed (dog 2) metastatic disease.

CONCLUSION

Percutaneous MWA of pulmonary nodules was technically feasible in two dogs without major complications.

CLINICAL SIGNIFICANCE

Percutaneous MWA may provide a minimally invasive option for treatment of osteosarcoma pulmonary metastases. Additional studies are required to evaluate the benefits of MWA on survival and confirm histologic cell death within pulmonary neoplastic lesions.

Use of a cavitron ultrasonic surgical aspirator for parenchyma-sparing and complex liver resections in dogs

OBJECTIVE

To report the clinical use of a cavitron ultrasonic surgical aspirator (CUSA) for the resection of hepatic lesions in dogs.

STUDY DESIGN

Clinical prospective study.

ANIMALS

Eleven client-owned dogs.

METHODS

Dogs requiring a hepatic nodulectomy, segmentectomy, and/or a lobectomy (including complex lobectomies) were enrolled. The number and location of procedures, blood loss, duration of surgery, and short-term complications were recorded.

RESULTS

Dogs underwent a mean of 2.3 ± 1.1 procedures. All masses were amenable to surgical excision regardless of their location and their relationship with major hepatic vessels. Dogs lost a median of 77 mL of blood (9.9-161), which corresponded to 4.3% of blood volume (0.8%-23.2%). The dog with the highest blood loss survived without requiring transfusion. The median duration of all CUSA procedures was 33.5 minutes (15-82). Short-term outcomes were assessed for the first 15 days, during which two complications were diagnosed. Cholangiohepatitis was diagnosed in one dog and resolved after medical management, and another dog developed necrotic pancreatitis and died.

CONCLUSION

Liver parenchyma-sparing nodulectomies and segmentectomies and liver lobectomies including complex lobectomies were achieved with a CUSA in all dogs.

CLINICAL SIGNIFICANCE

Use of a CUSA can be considered as an alternative for the removal of hepatic lesions in dogs.

Intestinal surgery in small animals: historical foundations, current thinking, and future horizons

Intestinal wounds require precise closure after intestinal biopsy, enterotomy, or enterectomy in small animals. Preexisting factors such as intra-abdominal sepsis and hypoalbuminemia as well as poor surgical technique increase the risk of intestinal dehiscence, with considerable negative impact on patient morbidity and mortality. Live dog studies have demonstrated the dangers of mucosal eversion especially in the septic abdomen. Approximating patterns preserve luminal diameter, heal optimally, and have equal bursting strength compared with inverting patterns after 24 hours. Simple interrupted and simple continuous suture patterns and disposable skin staples are established alternatives for manual wound closure. Knotless quilled suture currently used in laparoscopic gastropexy techniques shows bursting strength equal to monofilament sutures in dog cadaveric intestine. Dehiscence rates with hand sewn vs titanium automated stapling anastomosis are similar in uncomplicated cases; however, auto stapling devices may be the preferred method of anastomosis when preexisting abdominal sepsis is present and when patient size allows it. Regardless of the technique, current standard of care involves leak testing and omental wrapping, followed by early postoperative feeding. The past decade has ushered in an exciting new era of laparoscopic assisted techniques that have the potential to reduce postoperative pain and patient morbidity. An understanding of these applications will establish the future of minimally invasive small animal intestinal surgery for veterinary specialists. In summary, surgeons have a variety of methods at their disposal for optimal clinical outcome in small animal intestinal surgery.

Hepatic Hemangiosarcoma in a Cynomolgus Macaque (Macaca fascicularis)

An experimentally naïve, 9-y-old, intact male cynomolgus macaque was reported for bleeding from an unidentified site. Sedated physical examination indicated mild gingival separation from the lingual aspect of the upper right canine tooth as the source of the hemorrhage. Physical exam revealed a firm mass adhered to the left zygomatic arch, 2 subcutaneous nodules on the chest, and a large mass in the cranial abdomen. Radiographs revealed a large soft-tissue mass in the cranial abdomen and multifocal nodules in the caudal lung fields. On ultrasonography, the liver was grossly enlarged and contained a cavi- tated mass. Hematology and serum chemistry results demonstrated severe regenerative anemia with normal clotting times and adequate platelet count. For humane reasons, euthanasia was elected. On gross examination, the liver was markedly enlarged by an expansile mass primarily affecting the median lobe, with multiple, smaller nodules throughout the remaining lobes. Multifocal round, firm nodules were observed on the surface of all lung lobes and throughout the omentum. Histologic examination of the hepatic, cutaneous, osseous, and pulmonary lesions demonstrated well-defined, endothelium-lined vascular channels arranged in cords with abundant hemorrhage; endothelial-cell immunomarkers confirmed these results. On the basis of these findings, hepatic hemangiosarcoma, with metastases to the lungs, omentum, subcutis, and bone, was diagnosed. This case study is the first report of spontaneous hepatic hemangiosarcoma in a cynomolgus macaque and the first case with metastasis to bone in a NHP.