Advances in the Treatment of Chylothorax

Idiopathic chylothorax is a challenging clinical condition historically associated with poor resolution rates following surgical intervention. Recent advances in imaging and surgical techniques have revolutionized the treatment of this disease process. Computed tomographic lymphangiography has facilitated improved surgical planning and postoperative assessment, while intraoperative use of near-infrared fluorescence imaging aids in highly accurate intraoperative thoracic duct identification. Utilizing these advancements, minimally invasive surgical techniques have been successfully developed and have been associated with considerable improvements in surgical outcomes.

Evaluation of thoracic duct ligation and unilateral subphrenic pericardiectomy via a left fourth intercostal approach in normal canine cadavers

OBJECTIVE

To investigate a left-sided fourth intercostal approach to thoracic duct (TD) ligation and unilateral subphrenic pericardiectomy in dogs.

STUDY DESIGN

Retrospective computed tomography (CT) review and cadaveric study.

ANIMALS

Thirteen dogs with idiopathic chylothorax and 10 canine cadavers.

METHODS

A retrospective study of CT lymphangiograms in client-owned dogs with idiopathic chylothorax evaluated location and branching of the TD at the left fourth intercostal space. A cadaveric study evaluated the efficacy of TD ligation at this site. Following methylene blue mesenteric lymph node injection, TDs were identified through a left fourth intercostal thoracotomy, ligated, and sealed. Unilateral subphrenic pericardiectomy was performed through the same incision. Computed tomography scans were performed to determine the success of TD ligation.

RESULTS

A review of lymphangiograms revealed a single TD in 10/13 clinical cases at the fourth intercostal space. Three cases had additional branches. Thoracic duct ligation via a left fourth intercostal thoracotomy was successful in nine out of 10 cadavers. A single branch was noted intraoperatively in six out of 10, and two branches were noted in four out of 10 cadavers. All branches were observed on the left side of the esophagus.

CONCLUSION

TD ligation at the left fourth intercostal space was successfully performed in 9/10 canine cadavers and appeared feasible in a retrospective review of 10/13 clinical cases. Unilateral subphrenic pericardiectomy can also be performed via this approach.

CLINICAL SIGNIFICANCE

Fewer thoracic duct branches at this location in comparison with the standard caudal location may simplify TD ligation. If elected, unilateral subphrenic pericardiectomy can be performed through the same incision. Further investigation in clinical patients is warranted.

Thoracoscopic Assisted PleuralPortTM Application in Seven Dogs Affected by Chronic Pleural Effusion

Chronic non-septic pleural effusion is a condition that frequently may occur because of lung or pleural neoplasia, or chylothorax refractory to surgical treatment, in dogs. Effusion management can be performed with multiple pleurocenteses or the application of chest drains. New modified vascular devices have been used for patients with chronic diseases; they offer the advantage of allowing home management and do not require hospitalization. Eight PleuralPort^TM devices were applied in seven dogs during thoracoscopic exploration and biopsy procedures; five were affected by mesothelioma; one by lung metastases from a mammary carcinoma; and one by chronic chylothorax. The median time of surgical procedure was 51 min; one developed pneumothorax post-operatively that resolved within 12 h after repeated drainage; one device was obstructed after 45 days and was successfully managed by flushing. All patients were discharged after 24 h. The median duration of port insertion in cancer patients was 5 months and those dogs were euthanized because of tumor progression; in the dog with chylothorax, the device was removed after 1 year when the effusion had resolved.

Resolution, recurrence, and chyle redistribution after thoracic duct ligation with or without pericardiectomy in dogs with naturally occurring idiopathic chylothorax

OBJECTIVE

To document outcomes of thoracoscopic treatment of idiopathic chylothorax (IC) in dogs with and without constrictive pericardial physiology (CPP) and evaluate patterns of chyle flow redistribution after thoracic duct ligation (TDL).

ANIMALS

26 client-owned dogs.

PROCEDURES

In this prospective cohort study, echocardiography and cardiac catheterization were performed to document CPP in dogs with IC. Thoracoscopic TDL with pericardiectomy was performed if CPP was present (TDL/P group). Dogs without evidence of CPP underwent thoracoscopic TDL alone (TDL group). Dogs underwent preoperative, immediate postoperative, and 3-month postoperative CT lymphangiography studies when possible. Perioperative morbidity, resolution and late recurrence rates, and long-term outcome were recorded.

RESULTS

17 dogs underwent TDL, and 9 underwent TDL/P. Twenty-five of 26 (96%) survived the perioperative period. One dog died from ventricular fibrillation during pericardiectomy. Resolution rates for TDL and TDL/P were 94% and 88%, respectively (P = .55), with 1 late recurrence occurring in the TDL group in a median follow-up of 25 months (range, 4 to 60 months). On 3-month postoperative CT lymphangiography studies, ongoing chyle flow past the ligation site was demonstrated in 5 of 17 dogs, of which 1 dog developed recurrence at 13 months postoperatively. In 15 of 17 dogs, chylous redistribution after TDL was principally by retrograde flow to the lumbar lymphatic plexus.

CLINICAL RELEVANCE

In dogs without evidence of CPP, TDL alone was associated with a very good prognosis for treatment of IC. In the absence of CPP, the additional benefit of pericardiectomy in the treatment of IC is questionable.

Prospective evaluation of lymphatic embolization as part of the treatment in dogs with presumptive idiopathic chylothorax

OBJECTIVE

To describe the embolization technique and short-term clinical outcome in dogs undergoing lymphatic embolization (LE) as part of treatment for presumptive idiopathic chylothorax (IC). Additionally, to document findings in computed tomography lymphangiography (CTLa) following embolization.

STUDY DESIGN

Prospective case series ANIMALS: Eight client-owned dogs.

METHODS

Dogs underwent CTLa followed by thoracic duct ligation (TDL), pericardiectomy (PC) and LE. A mixture of 3:1 lipiodol: n-butyl cyanoacrylate embolic solution was injected through a catheterized mesenteric lymphatic vessel via limited abdominal approach using intraoperative fluoroscopy. CTLa was scheduled for 12 weeks postoperatively, and long-term follow-up was obtained via telephone contact.

RESULTS

LE was technically successful in six of the eight dogs; and clinically successful in five of the six dogs. In the unsuccessful dog, a diagnosis of lymphangiosarcoma was determined, and the owners elected for euthanasia. Five dogs who underwent successful LE underwent CTLa at 12 weeks. Complete resolution of pleural effusion occurred in three dogs and scant pleural effusion in two dogs. A robust lymphatic embolus preventing antegrade continuation of radiocontrast was documented in all five dogs. Five of the six dogs that underwent LE, are alive and clinically normal at 358-960 days postoperatively.

CONCLUSIONS

LE is feasible as part of treatment for dogs with IC. Additionally, a robust lymphatic embolus and lack of radiocontrast flow past the embolus was documented at 12 weeks following surgery.

CLINICAL SIGNIFICANCE

LE has the potential to reduce surgical failure by reducing efferent lymphatic chyle flow, occluding missed lymphatic branches and preventing the development of collateral branches.

Triple-combination surgery with thoracic duct ligation, partial pericardiectomy, and cisterna chyli ablation for treatment of canine idiopathic chylothorax

This study aimed to evaluate the outcomes and complications of triple-combination surgery consisting of thoracic duct ligation (TDL), partial pericardiectomy (PPC), and cisterna chyli ablation (CCA) for the treatment of idiopathic chylothorax in dogs. Eleven privately owned dogs with idiopathic chylothorax underwent the triple-combination surgery: TDL and PPC were performed in left recumbency, followed by CCA in dorsal recumbency. Of the 11 dogs, seven were Shiba, two were Afghan hounds, and one each was Borzoi and mixed-breed. TDL and PPC required two intercostal thoracotomies in five dogs, whereas they were performed through a single intercostal incision in the other dogs. None of the dogs showed major intraoperative complications. The median operation time was 190 min (range, 151–234 min). Nine dogs showed no pleural effusion after surgery without medical management. Another dog showed the disappearance of chylous effusion, followed by the pleural accumulation of modified transudate. However, the residual one dog in whom chylothorax did not improve postoperatively died 4 months after the combination surgery. The mortality rate at the conclusion of this study was 9.1%. Although the triple-combination surgery with TDL, PPC, and CCA was complex and required a prolonged operation time, the success rate of resolving chylothorax in our study was comparable to that of open surgery as previously reported. Therefore, this study suggests that such triple-combination surgery can become one of the therapeutic options for the management of canine idiopathic chylothorax.

Thoracoscopic detection of thoracic ducts after ultrasound-guided intrahepatic injection of indocyanine green detected by near-infrared fluorescence and methylene blue in dogs

OBJECTIVE

To describe and compare onset and intensity of thoracic duct (TD) coloration in healthy dogs after intrahepatic injection of either indocyanine green (ICG) visualized by intraoperative near-infrared fluorescence lymphography (NIRFL) or direct thoracoscopic visualization of methylene blue dye (MB).

STUDY DESIGN

Prospective study.

ANIMALS

Healthy adult Beagle dogs (n = 5).

METHODS

All dogs had biochemical panels and complete blood counts preoperatively. Computed tomography lymphography (CTL) was performed prior to a standard 3-port thoracoscopic approach. A mixture of MB and ICG was injected by ultrasound-guided percutaneous injection into right or left-sided hepatic lobes. Data collected included dose of contrast agent (MB vs. ICG), injection site, timing, and quality of operative TD identification. Potential hepatic injury was assessed by repeat laboratory evaluation and abdominal ultrasound 14 days postoperatively.

RESULTS

Preoperative CTL provided a diagnostic study in 5/5 dogs. After intrahepatic injection of combined dyes, NIRFL allowed visualization of TDs in 5/5 dogs, but MB did not result in visible TD coloration in any dog. Intrahepatic injection of ICG achieved successful NIRFL in a median time of 6 minutes and persisted for the 20 minute observation period in all five dogs. All dogs recovered without complication and were subsequently adopted.

CONCLUSION

NIRFL of the TD can be achieved with intraoperative hepatic injection of ICG. Intrahepatic injection of MB did not result in visible TD coloration.

CLINICAL SIGNIFICANCE

Hepatic intra-parenchymal injection is a reliable alternative portal into the TD system for intraoperative visualization of TD anatomy using ICG in dogs.

Evaluation of Thoracoscopic Pericardial Window Size and Execution Time in Dogs: Comparison of Two Surgical Approaches

Pericardial effusion presents clinicians with a challenge when diagnosing the underlying cause and performing a prognosis. Different techniques have been suggested for canine thoracoscopic pericardiectomy with the creation of variable pericardial window size. The aim of this study was to statistically compare the surgical time and achieved window size of the paraxiphoid transdiaphragmatic and monolateral intercostal approaches. The paraxifoid and monolateral intercostal approaches showed a mean surgical time of 55 ± 20.08 (SD) minutes and 13.94 ± 4.61 (SD) minutes, and a mean pericardial window diameter of 4.23 ± 0.80 (SD) cm and 3.31 ± 0.43 (SD) cm, respectively. A significant correlation was observed between the dogs' bodyweight and window size (r = 0.48; p = 0.04) for both surgical approaches, and between the dogs' bodyweight and surgical time (r = 0.72; p = 0.0016) for monolateral intercostal approach. All treated dogs showed no clinical signs of recurrent cardiac tamponade during the follow-up. Our results provided useful information to help surgeons make the definitive choice of the surgical technique to treat the pericardial effusion.

Canine idiopathic chylothorax: Anatomic characterization of the pre- and postoperative thoracic duct using computed tomography lymphography

Surgical treatment has improved the prognosis of canine idiopathic chylothorax, although a recurrence of the disease occurs occasionally after the procedure. An improved understanding of possible causes for this recurrence would be helpful for prognosis and treatment planning in affected patients. In this retrospective case series study, we described the detailed pre- and postoperative computed tomographic lymphography (CTLG) imaging characteristics for a group of dogs with surgically confirmed idiopathic chylothorax. Preoperative CTLG was performed in 12 of 14 dogs diagnosed with idiopathic chylothorax. Thoracic ducts were present on the right side in 10 dogs, left side in one dog, and bilaterally in one dog. All the 14 dogs received a combination therapy of pericardiectomy and thoracic duct ligation (TDL) by video-assisted thoracoscopic surgery. One week after surgery, a postoperative CTLG was performed, and the thoracic ducts were apparent in seven of 14 dogs. Three dogs had an unchanged course of the thoracic duct, which could have resulted from a missed duct. Four dogs were identified as having a bypass formation: the oblique duct originated at the ligation site and connected to the duct on the other side. Our findings indicated that one of the possible causes for postoperative recurrence of chylothorax in dogs could be "invisible or sleeping" fine ducts that are collapsed and not visible in preoperative CTLG scans. After TDL causes a change in the pressure of lymphatic flow, these fine thoracic ducts may become apparent using postoperative CTLG.

Feasibility of thoracoscopic attenuation of the azygos vein as a model for portoazygos shunts: A canine cadaveric study

OBJECTIVE

To evaluate the feasibility of thoracoscopic placement of three vascular attenuation devices by using the azygos vein as a model for portoazygos (PA) shunts and to describe the approach for thoracoscopic placement of these attenuation devices in small breed dogs.

STUDY DESIGN

Randomized, prospective, cadaveric study.

ANIMALS

Cadavers of 10 adult small breed dogs.

METHODS

Cadavers were placed in sternal recumbency with left dorsolateral obliquity, and three thoracoscopic ports were established in the right hemithorax at the mid-10th intercostal space and dorsal third of the ninth and 11th intercostal spaces. The caudal azygos vein was thoracoscopically isolated along three adjacent segments bordered by four intercostal arteries, beginning just cranial to the first intercostal artery visualized cranial to the diaphragm. Three attenuation devices including coated cellophane, uncoated cellophane, and a 5-mm ameroid constrictor were thoracoscopically placed around one segment in each dog. Minor port access modifications were required to improve working space and triangulation in three dogs. Ability to successfully place the device, time required for placement, endoscopic clip configuration, and complications associated with placement were recorded.

RESULTS

Median dog weight was 7.7 kg (range, 1.8-11). All attenuation devices were successfully placed thoracoscopically in all cadavers. No difference was detected in time required for placement between the ameroid constrictor and coated and uncoated cellophane (range, 2.3-33.8 minutes, P = .8).

CONCLUSION

Ameroid constrictors and thin film bands were consistently placed via thoracoscopy around the caudal azygos vein of small breed dogs.

CLINICAL SIGNIFICANCE

These results justify further investigation of thoracoscopic PA shunt attenuation in affected dogs.

Anatomic and volumetric characterization of the cisterna chyli using CT lymphangiography and computer-assisted design software in dogs with idiopathic chylothorax

The objectives of this retrospective, observational study were to characterize the anatomical features of the cisterna chyli (CC) in a cohort of dogs diagnosed with idiopathic chylothorax that underwent CT lymphangiography (CTLa), and to evaluate the feasibility of computer-assisted design (CAD) software to quantify volumetric measurements of the CC. Twenty-three client-owned dogs with idiopathic chylothorax were included. Additionally, CTLa was performed in three canine cadavers to assess the ability of CAD software to accurately acquire volumetric measurements. Injection sites, attenuation values, anatomic location, dimensions, and aortic diameter to CC ratio (Ao:CC) were recorded. Video records of video-assisted thoracic surgery (VATS) thoracic duct ligation (TDL) were reviewed in eight out of 23 dogs to compare operative and CTLa findings. The CC was dorsal and right-sided in 18 out of 23 dogs, located between L1 and L4 in 21 dogs, and extended as far cranially as T11 in two dogs. The median measurements for length, height, and width were 150.0, 5.5, and 13.3 mm, respectively. Median total volume was 1.82 mL. Median volumes to the right and left of the aorta were 1.46 and 0.49 mL, respectively (P = .014). Median total CC volume to body weight ratio (CC:bw) was 0.07 mL/kg. The presence of an intrathoracic CC was observed intraoperatively in six out of eight cases that underwent VATS TDL. Findings supported the use of CTLa and CAD as feasible methods for characterizing the CC in dogs diagnosed with chylothorax. These methods may facilitate interventional planning involving the CC such as embolization.

Efficacy of en bloc thoracic duct ligation in combination with pericardiectomy by video-assisted thoracoscopic surgery for canine idiopathic chylothorax

OBJECTIVE

To compare the outcomes of pericardiectomy performed with conventional clipping thoracic duct ligation (C-TDL) to those with en bloc thoracic duct ligation (EB-TDL) using video-assisted thoracoscopic surgery (VATS) for canine idiopathic chylothorax.

STUDY DESIGN

Retrospective consecutive case series.

ANIMALS

Thirteen client-owned dogs with idiopathic chylothorax.

METHODS

Medical records of dogs treated with pericardiectomy in combination with TDL by VATS without intraoperative contrast were reviewed. Five and seven dogs underwent C-TDL and EB-TDL, respectively, and 11 dogs were evaluated by preoperative and 7- to 10-days-postoperative computed tomography-lymphography (CTLG). No clinical symptoms with absent or minimal pleural effusion was defined as clinical improvement. Long-term remission (LTR) was defined as rapid resolution of pleural effusion and no recurrence for more than 1 year. Anesthesia time, operation time, the duration of hospitalization, and time until pleural effusion resolution were compared.

RESULTS

Clinical improvement was achieved in 91.7% of the cases (C-TDL, 4/5; EB-TDL, 7/7), excluding one case of intraoperative death. The LTR rate was significantly higher with EB-TDL (6/7 [85.7%]) than with C-TDL (1/5 [20%]). Anesthesia time, operation time, and time until pleural effusion resolution were significantly better with EB-TDL than with C-TDL. The rates of thoracic ducts visualization by postoperative CTLG were 100% (5/5) with C-TDL and 42.9% (3/7) with EB-TDL.

CONCLUSION

En bloc TDL was an effective treatment for canine idiopathic chylothorax in this patient population. It compared favorably to C-TDL, although missed branches at the time of surgery may explain the difference between C-TDL and EB-TDL in this small population of cases.

CLINICAL SIGNIFICANCE

En bloc TDL by VATS was an effective minimally invasive treatment for canine idiopathic chylothorax. Computed tomography-lymphography can be used for surgical planning and postoperative evaluation.

Canine and Feline Exudative Pleural Diseases

Exudative pleural diseases are a common cause of respiratory distress and systemic illness in dogs and cats. This article covers the pathophysiology, development, and classification of exudative pleural effusions. The most current diagnostic strategies, causes, imaging findings, and medical or surgical treatment options for select diseases are reviewed in detail.

Treatment of idiopathic chylothorax in dogs and cats: A systematic review

OBJECTIVE

To evaluate the evidence published on the treatment of idiopathic chylothorax (IC) in small animals.

STUDY DESIGN

Systematic literature review.

SAMPLE POPULATION

Dogs and cats with IC.

METHODS

A literature search was performed in three bibliographic databases in July 2018 for publications on IC in dogs and cats. Articles meeting criteria for inclusion were evaluated for treatment, survival, outcome data, and level of evidence (LoE) with a modified Oxford Level of Evidence (mOLE) and GRADE (Grading of Recommendations, Assessment, Development and Evaluations) system.

RESULTS

Eleven of 313 identified articles met the inclusion criteria. Only one study was identified in dogs as having higher LoE by using the mOLE system, whereas no study was identified as such in either species with the GRADE system. Surgery was the primary treatment in all dogs and in 93% (68/73) of cats. Medical therapy was the primary treatment in 7% (5/73) of cats. The most common surgical treatment combined thoracic duct ligation (TDL) and subtotal pericardiectomy (SP; 40%; 34/84) in dogs and TDL in cats (51% [37/73]).

CONCLUSION

The body of literature for IC treatment in small animals was limited to one higher LoE study in dogs and none in cats. No strong conclusion could be drawn regarding the effectiveness of any one surgical method in dogs or cats, and no evidence was found to support medical therapy as a primary treatment.

CLINICAL SIGNIFICANCE

The best available evidence regarding the treatment of IC is published in dogs and provides some support for surgical treatment with either TDL + cisterna chyli ablation or TDL + SP. Additional evidence is required to confirm this finding.

Outcomes of dogs with recurrent idiopathic pericardial effusion treated with a 3-port right-sided thoracoscopic subtotal pericardiectomy

OBJECTIVE

To describe a 3-port right-sided thoracoscopic subtotal pericardiectomy (TSP) to treat dogs with recurrent idiopathic pericardial effusion (RIPE) and report their long-term survival.

STUDY DESIGN

Retrospective case series.

ANIMALS

Sixteen client-owned dogs.

METHODS

Medical records were searched for dogs with idiopathic pericardial effusion that recurred after 1 or more pericardiocenteses and treated with a 3-port right-sided technique (1 subxiphoid camera port and 2 instrument ports on the right side of the dog). Follow-up consisted of direct examination or communication with referring veterinarians or owners.

RESULTS

Thoracoscopic subtotal pericardiectomy was successfully completed in all dogs, with no surgical complications. The median duration of postoperative follow-up was 191.5 days (range, 5-1345). The median survival time (MST) after surgery was 365 days (range, 5-1345); MST of dogs with a histopathological diagnosis of neoplasia (n = 4) was 76 days, whereas dogs with no evidence of neoplasia had an MST of 367 days (n = 12, P = .14). Recurrent pleural effusion was the ultimate cause of death or reason for euthanasia in 8 of 16 dogs.

CONCLUSION

The technique described here resulted in similar surgical times and outcomes for dogs undergoing TSP for RIPE compared with previous studies. Neoplasia was identified in 4 of 16 dogs.

CLINICAL SIGNIFICANCE

Thoracoscopic subtotal pericardiectomy can be readily performed with only 2 instrument ports, both on the same side of the dog, and without 1-lung ventilation. Recurrent pleural effusion led to the death of half of the dogs in this series.

Epicardial exposure provided by a novel thoracoscopic pericardectomy technique compared to standard pericardial window

OBJECTIVE

(1) To describe a novel technique for thoracoscopic pericardectomy using a pericardial window with vertical pericardial fillets (PW+F). (2) To compare epicardial exposure between a standard pericardial window (PW) and PW+F.

STUDY DESIGN

Experimental study.

ANIMALS

Purpose-bred research dogs (n = 12).

METHODS

PW was performed through a 3-port subxiphoid thoracoscopic approach. After PW, vertical fillets were made in the pericardium for PW+F. Thoracoscopic images from 3 views were acquired after each procedure, and percentage of epicardial surface exposed (PESE) was compared. Epicardial exposure and iatrogenic damage to surrounding structures were directly assessed via postmortem gross examination.

RESULTS

The exposed epicardial surface (PESE) was increased with our novel compared to the standard technique. Median surgery time for PW+F was 25 minutes. The procedure was performed in 11 of 12 dogs without iatrogenic damage to surrounding structures. In 1 dog, the electrosurgery device contacted the epicardium and caused fatal ventricular fibrillation while performing PW+F. Based on postmortem assessment in all dogs with PW+F, the pericardium could move freely away from the heart, exposing the majority of the epicardial surface.

CONCLUSION

Thoracoscopic PW+F is a novel technique that improves the exposure of the epicardium compared to standard PW. While PW+F can be performed successfully and in an efficient manner, the surgeon must be aware of the risk of iatrogenic trauma to thoracic structures when using electrosurgery.

CLINICAL RELEVANCE

PW+F offers a relatively safe, efficient, and effective minimally invasive method that improves the exposure of the epicardium compared to PW.

Thoracic duct lymphography by subcutaneous contrast agent injection in a dog with chylothorax

A 4-year-old male Japanese Shiba Inu presented with recurrent chylothorax. The thoracic duct was successfully imaged using computed tomography after the injection of an iodine contrast agent into the subcutaneous tissue surrounding the anus. The thoracic duct was successfully ligated and pericardectomy performed via an open thoracotomy. Pleural effusion improved but relapsed a week after the surgery. A second lymphography revealed a collateral thoracic duct that was not detected during the first lymphography. The collateral duct was ligated and chylothorax was resolved after the second surgery. The lymphography applied in this study was minimally-invasive and easily provided images of the thoracic duct in a dog with chylothorax.

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.

Use of surgery and mitoxantrone chemotherapy in a dog with disseminated lymphangiosarcoma

CASE DESCRIPTION

A 5-year-old sexually intact male Giant Schnauzer was evaluated because of difficulty breathing and left pelvic limb swelling. Eighteen months previously, the patient had had intermittent left pelvic limb swelling, but the owner declined further testing at that time.

CLINICAL FINDINGS

Physical examination revealed severe pitting edema of the left pelvic limb and prepuce and muffled heart sounds on thoracic auscultation. Results of thoracic radiography and thoracocentesis were consistent with chylothorax, and CT imaging of the thorax and abdomen revealed a mass involving the whole left sublumbar area.

TREATMENT AND OUTCOME

In an attempt to treat the chylothorax, pleural omentalization and pericardectomy were performed. Histologic evaluation of several biopsy specimens harvested in the abdominal and thoracic cavities revealed disseminated lymphangiosarcoma. The patient recovered well from surgery, and mitoxantrone chemotherapy was administered. As of 10 months after surgery, the dog was clinically normal except for mild pelvic limb edema.

CLINICAL RELEVANCE

The combination of clinical signs, multiple imaging features, surgical findings, and histologic examination findings enabled the final diagnosis of lymphangiosarcoma. Clinical management that included medical and surgical treatments and chemotherapy resulted in improved quality of life and extended survival time in a dog with metastatic lymphangiosarcoma.

Prevalence, outcome and risk factors for postoperative pyothorax in 232 dogs undergoing thoracic surgery

Objective

To determine the prevalence, outcome and risk factors for postoperative pyothorax in dogs undergoing thoracic surgery.

Methods

Case records were reviewed retrospectively to identify dogs with post thoracic surgery pyothorax, defined as septic neutrophilic inflammation within the pleural space based on cytology and/or a positive bacterial culture of pleural fluid. Those identified were reviewed for potential risk factors for postoperative pyothorax based on biological plausibility and previously published data. These potential risk factors were explored by multivariable logistic regression.

Results

Of 232 dogs undergoing thoracic surgery, 15 (6·5%) dogs developed pyothorax. Bacteria cultured included methicillin-resistant Staphylococcus aureus and multi-resistant Escherichia coli. Of these dogs, six died, four were euthanased and five were treated successfully. A diagnosis of idiopathic chylothorax [Odds Ratio (OR)=12·5, 95% Confidence Interval (CI)=2·7-58·5, P=0·001], preoperative intrathoracic biopsy (OR=14·3, 95% CI=1·7-118·7, P=0·014) and preoperative thoracocentesis (OR=11·2, 95% CI=1·6-78·2, P=0·015) were identified as independent risk factors for development of postoperative pyothorax.

Clinical Significance

Idiopathic chylothorax, intrathoracic biopsy and prior thoracocentesis are independent risk factors for postoperative pyothorax, which was associated with a 67% mortality rate.

Thoracoscopic en bloc thoracic duct sealing and partial pericardectomy for the treatment of chylothorax in two cats

Two cats with intractable idiopathic chylothorax and a history of unsuccessful medical management were treated thoracoscopically with en bloc thoracic duct sealing and subtotal pericardectomy using a bipolar feedback-controlled vessel sealing device. No surgical complications were observed. Twenty-four and 26 months after surgery, both cats were free of thoracic effusion and clinical signs.

Occlusion of the thoracic duct using ultrasonically activated shears in six dogs

OBJECTIVE

To assess the feasibility of sealing the thoracic duct (TD) in dogs using ultrasonically activated shears via thoracoscopy.

STUDY DESIGN

In vivo experimental study.

ANIMALS

Mature dogs (n = 6).

METHODS

Dogs were anesthetized without pulmonary exclusion and positioned in left lateral recumbency. Lymphangiography was performed to identify TD anatomy. Methylene blue was injected into the lymphatic catheter to identify the TD and its branches. Under thoracoscopic guidance (right dorsal 8-10th intercostal spaces), the TD was sealed with an ultrasonic device and lymphangiography was repeated. If the flow of contrast continued beyond the occlusion site, additional attempts to seal the duct were made. Dogs were euthanatized, the TD was excised and fixed in formalin for histopathology.

RESULTS

Thoracoscopic identification of the TD was possible in 5 dogs. Three dogs required conversion to a thoracoscopic-assisted approach and 3 dogs required resealing of the TD closer to the diaphragm. Thoracic duct occlusion (TDO) was ultimately achieved in all 6 dogs based on follow-up lymphangiography. TDO by tissue coagulation was confirmed by histopathology.

CONCLUSIONS

Thoracoscopic identification and occlusion of the TD using ultrasonically activated shears with bilateral lung ventilation is technically feasible in normal dogs and provides a less invasive alternative to open thoracotomy procedures.