The Effect of Cisterna Chyli Ablation Combined with Thoracic Duct Ligation on Abdominal Lymphatic Drainage

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.

Computed tomography lymphangiography via intrametatarsal pad injection is feasible in cats with chylothorax

OBJECTIVE

To evaluate the feasibility of CT lymphangiography via intrametatarsal pad injection in cats with chylothorax.

ANIMALS

7 client-owned cats.

PROCEDURES

This was a multicenter, retrospective, descriptive study. Medical records and imaging data from 4 veterinary hospitals were reviewed to identify cats with chylothorax that had undergone intrametatarsal pad injection via CT lymphangiography. In total, 7 client-owned cats were included in the study. Signalment, history, image findings, and follow-up data were recorded. Descriptive statistics were used to analyze the success rate of thoracic duct (TD) enhancement and describe relevant clinical findings.

RESULTS

Enhancement of TDs was successful in 6 of the 7 cats within 5 to 15 minutes after initiating intrametatarsal pad injection under general anesthesia. Successful migration of contrast medium into the lymphatic vessels cranial to the popliteal lymph nodes was observed in all cats within 5 minutes after injection. The recommended dose of contrast medium to achieve TD enhancement was 1 mL/kg (0.5 mL/kg/pad; concentration, 350 mg of iodine/kg). Only 1 cat had mild swelling of the paws after the procedure, and it recovered quickly without pain medication; no cats experienced lameness. Similar to dogs and unlike in previously published reports, 72% of TD branches were located in the right hemithorax.

CLINICAL RELEVANCE

CT lymphangiography via intrametatarsal pad injection is a feasible and safe procedure for cats with chylothorax. This technique provides detailed information regarding the unique TD anatomy and cisterna chyli location. It also contributes to surgical planning.

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.

Morphology of the cisterna chyli in nine dogs with idiopathic chylothorax and in six healthy dogs assessed by computed tomographic lymphangiography

OBJECTIVE

To describe the morphology of the lymphatics in the region of the cisterna chyli in healthy dogs and in dogs with idiopathic chylothorax by using computed tomographic lymphangiography.

STUDY DESIGN

Retrospective study.

ANIMALS

Nine dogs with idiopathic chylothorax and six healthy dogs.

METHODS

Computed tomographic lymphangiograms were reviewed to evaluate the number of cisterna chyli branches, total cross-sectional area of the branches normalized to the cross-sectional area of the aorta, number of branches with cross-sectional area greater than 25% of the aorta cross-sectional area, and ratio of the total perimeter to the total cross-sectional area of the branches. Data (mean ± SD) were compared between unaffected dogs and dogs with idiopathic chylothorax.

RESULTS

The cisterna chyli included more branches in dogs with chylothorax (4.30 ± 1.57) than in unaffected dogs (1.67 ± 0.56, P = .02), occupying a relative perimeter approximately double that in unaffected dogs (P < .001). The relative cross-sectional area of the cisterna chyli was approximately twofold smaller in affected (0.73 ± 0.35) than in unaffected (1.63 ± 0.91, P = .02) dogs. The fraction of dogs with branches greater than 25% of the cross-sectional area of the aorta tended to be larger in unaffected dogs (P = .07). Most larger branches were located dorsal or to the right of the aorta.

CONCLUSION

The cisterna chyli of dogs with idiopathic chylothorax contained smaller and more numerous branches compared with that of unaffected dogs.

CLINICAL SIGNIFICANCE

Altered cisterna chyli morphology may impact the surgical approach for cisterna chyli ablation in dogs with idiopathic chylothorax.

Lymphaticovenous anastomosis of the caudal thoracic duct to an intercostal vein: A canine cadaver study

OBJECTIVE

To describe a technique for anastomosis of the thoracic duct (TD) to the 11th or 12th intercostal vein (ICV) using a microvascular anastomotic coupler (MAC) in the dog.

STUDY DESIGN

Cadaveric study.

ANIMALS

Eight beagles.

METHODS

A right paracostal laparotomy and 10th intercostal thoracotomy were performed in each dog. Mesenteric contrast lymphography was used to identify the TD and its branches on fluoroscopy. The TD and adjacent 11th or 12th ICV were isolated, double ligated, and divided using a surgical microscope. The caudal TD and proximal ICV were anastomosed in an end-to-end fashion using a 1.5 mm or 2 mm MAC. Mesenteric lymphography was repeated to document patency of the anastomosis.

RESULTS

The TD was identified via lymphography in all dogs; five dogs had a single duct, and three dogs had additional branches. The anastomosis was successful in all eight dogs, and flow into the azygos vein without leakage was confirmed via lymphography.

CONCLUSION

End-to-end anastomosis of the TD to an ICV using a MAC was technically feasible in the canine cadaver.

CLINICAL SIGNIFICANCE

Lymphaticovenous anastomosis combined with TD ligation may have application as a treatment for idiopathic chylothorax. By maintaining the flow of chyle from the abdominal lymphatics to the systemic circulation, this procedure may reduce the stimulus for collateral circulation and persistent flow to the cranial mediastinal lymphatics.

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.

Abdominal lymphatic drainage after thoracic duct ligation and cisterna chyli ablation in clinically normal cats

OBJECTIVE

To characterize abdominal lymphatic drainage in cats after thoracic duct ligation (TDL) and cisterna chyli ablation (CCA).

ANIMALS

7 purpose-bred research cats.

PROCEDURES

Baseline CT lymphangiography was performed. A popliteal lymph node was injected with iohexol, and images were acquired at 5-minute intervals for 15 minutes. Cats underwent TDL and CCA; methylene blue was used to aid in identifying lymphatic vessels. The CT lymphangiography was repeated immediately after and 30 days after surgery. All cats were euthanized and necropsied.

RESULTS

Results of baseline CT lymphangiography were unremarkable for all 7 cats. Only 5 cats completed the study. Leakage of contrast medium at the level of the cisterna chyli was seen on CT lymphangiography images obtained from all cats immediately after surgery. Evaluation of 30-day postoperative CT lymphangiography images revealed small branches entering the caudal vena cava in 2 cats, leakage of contrast medium into the caudal vena cava with no visible branches in 1 cat, and no contrast medium in the caudal vena cava in 2 cats. Contrast medium did not flow beyond the level of the cisterna chyli in any cat. Gross examination during necropsy revealed that all cats had small lymphatic vessels that appeared to connect to local vasculature identified in the region of the cisterna chyli.

CONCLUSIONS AND CLINICAL RELEVANCE

Abdominal lymphaticovenous anastomoses formed after TDL and CCA in cats. This would support use of these procedures for treatment of cats with idiopathic chylothorax, although additional studies with clinically affected cats are warranted.

Computed tomographic lymphangiography of the thoracic duct by subcutaneous iohexol injection into the metatarsal region

OBJECTIVE

To evaluate the efficacy of subcutaneous iohexol injection into the metatarsal region for thoracic duct lymphangiography in dogs and to determine the minimum effective dose.

STUDY DESIGN

Experimental study and clinical report.

ANIMALS

Five healthy beagle dogs and one dog with chylothorax.

METHODS

For the experimental study, iohexol was injected subcutaneously into the metatarsal region of five dogs at three doses (0.5, 0.75, and 1 mL/kg), and the injection sites were massaged gently. Computed tomography (CT) was performed 1, 3, 5, 7, 10, 15, and 20 minutes after iohexol injection. Subjective quality was assessed, and Hounsfield unit values were measured at several regions of interest (T1, T4, T8, T13, and L3). In the dog with chylothorax, iohexol (1.0 mL/kg) was injected into the right metatarsal region prior to CT.

RESULTS

The thoracic duct was visualized and enhanced by contrast in all dogs after injection of 0.75 and 1.0 mL/kg of iohexol, and in two dogs after injection of 0.5 mL/kg at 3, 5, and 7 minutes. The thoracic duct was gradually attenuated with increasing doses of iohexol. In the dog with chylothorax, the entire thoracic duct was well enhanced and dilated, and tortuous cranial mediastinal lymphatics were detected.

CONCLUSION

The thoracic duct was visualized when at least 0.75 mL/kg of iohexol was injected subcutaneously into the metatarsal region of dogs.

CLINICAL SIGNIFICANCE

Subcutaneous injection of iohexol into the metatarsal region offers a simple alternative to conventional thoracic duct lymphangiography.

Hybrid single-port laparoscopic cisterna chyli ablation for the adjunct treatment of chylothorax disease in dogs

OBJECTIVE

To describe a hybrid, single-port, minimally invasive cisterna chyli ablation (CCA) technique in clinical cases of canine idiopathic chylothorax and evaluate this technique as a method for mesenteric lymphangiography (ML) in canine cadavers and clinical cases of idiopathic chylothorax.

STUDY DESIGN

Cadaveric and retrospective study.

ANIMALS

Six canine cadavers and 14 client-owned dogs with naturally occurring idiopathic chylothorax.

METHODS

Both cadaveric and clinically affected dogs were placed in sternal recumbency. A wound retractor device (WRD) and a single-port device were placed in the abdominal flank 2-3 cm caudal to the 13th rib. Mesenteric lymphangiography was evaluated by using indocyanine green (ICG) in 6 canine cadavers. Single-port laparoscopic CCA was performed in all clinical cases with idiopathic chylothorax.

RESULTS

Successful ML was completed by using ICG in all 6 canine cadavers. A right- or left-sided single-port laparoscopic CCA was successfully performed in 14 dogs with naturally occurring idiopathic chylothorax. Mesenteric lymphangiography was successfully performed through the WRD in 11 of these cases. No intraoperative complications were reported. Three dogs developed severe chyloabdomen postoperatively, with 1 dog requiring multiple abdominocenteses.

CONCLUSION

Direct ML and single-port laparoscopic CCA was performed through a WRD in dogs positioned in sternal recumbency. Although minimal operative complications were noted, postoperative chyloabdomen was reported.

CLINICAL SIGNIFICANCE

This hybrid single-port laparoscopic technique performed in sternal recumbency allows both a CCA and an intraoperative ML through the same incision. This procedure may be combined with thoracoscopic thoracic duct ligation and pericardectomy for the treatment of idiopathic chylothorax in dogs.

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.

The effect of photodynamic therapy on cisterna chyli patency in rats

OBJECTIVE

To radiographically and histologically evaluate the effects of photodynamic therapy on the cisterna chyli in rats.

STUDY DESIGN

Experimental study.

ANIMALS

Adult male Sprague-Dawley rats (n = 60).

METHODS

Cecal lymph nodes were injected with the photodynamic compound verteporfin. A 690 nm, 500 mW diode laser was then directed at the area of the cisterna chyli for either 0, 1.5, or 3 minutes. Cisterna chyli patency was evaluated using lymphography, and histologic changes were evaluated on postoperative Days 1, 3, 5, 7, and 14.

RESULTS

Histologically, minimal to marked injury to the cisternal and/or pericisternal tissues was present in all treated rats at all time periods. Radiographically, 8/20 cisternae were occluded in the 1.5-minute treatment group (including 1/4 on Day 1, 2/4 on Day 3, 3/4 on Day 5, 0/4 on Day 7, and 2/4 on Day 14), and 9/20 cisternae were occluded in the 3-minute treatment group (including 0/4 on Day 1, 1/4 on Day 3, 3/4 on Day 5, 3/4 on Day 7, and 2/4 on Day 14). There was minimal to no histologic evidence of tissue injury in control rats. All control cisternae were radiographically open.

CONCLUSIONS

Further investigations into the timing of laser application and light dose, or alternative photodynamic agents are required to limit injury to adjacent tissues and to improve the effectiveness of cisternal photoablation.

Spontaneous Resolution of Postoperative Chylothorax Following Surgery for Persistent Right Aortic Arch in Two Dogs

Two young dogs underwent surgical management of a persistent right aortic arch (PRAA) and developed chylothorax postoperatively. In both cases, the surgical procedure and anesthetic recovery were uncomplicated and routine. Following surgery, both patients appeared bright, alert, responsive, and previous signs of regurgitation had resolved. Dyspnea and tachypnea developed 1–2 days postoperatively in each patient, and chylous effusion was detected on thoracocentesis. For each case, a diagnosis of chylothorax was based on cytology and triglyceride concentrations of the aspirated pleural fluid. Similar protocols for monitoring were used in the treatment of each patient’s chylothorax. The duration and volume of chylous effusion production were closely monitored via routine thoracostomy tube aspiration. Both dogs rapidly progressed to recovery with no additional complications. With diligent monitoring, chylothorax secondary to surgical trauma can resolve in a rapid, uncomplicated manner.

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.

Chylothorax Treated Via Thoracic Duct Ligation and Omentalization

Chylothorax is an uncommon, potentially life-threatening disease of dogs and cats. Medical records of 12 animals (five dogs and seven cats) undergoing surgical management of chylothorax from 2001 to 2005 were reviewed. All animals received thoracic duct ligation and thoracic omentalization. In some cases, a combination of subtotal pericardectomy and/or pleural stripping was also employed. All animals survived surgery, and none was lost to follow-up. Median survival time for cats was 209 days (range 2 to 1328 days), and for dogs it was 211 days (range 7 to 991 days). Although postoperative mortality was higher than in other recent studies, no complications could be directly attributed to thoracic omentalization. A controlled, prospective study is needed to compare outcomes of this management method to those of other methods.

Chylothorax Associated With a Congenital Peritoneopericardial Diaphragmatic Hernia in a Dog

A 2-year-old dog was presented with a 3-month history of increasing respiratory effort and rate, inappetence, and lethargy. Chest radiographs demonstrated significant pleural effusion, which was consistent with chyle on biochemical and cytological evaluations. Further diagnostic evaluation, including a thoracic computed tomographic scan, revealed a peritoneopericardial diaphragmatic hernia (PPDH) resulting in a large, fat-attenuating mass within the pericardium. The dog was taken to surgery for repair of the PPDH, pericardectomy, and cisterna chyli ablation. Rapid and permanent resolution of the chylothorax occurred postoperatively. This is the first reported case of chylothorax secondary to PPDH.

Chylothorax associated with tricuspid dysplasia and atrial septal defect in a bullmastiff

Transudate pleural effusion associated with tricuspid dysplasia and ostium secundum-type atrial septal defect was diagnosed in a 14-month-old bullmastiff. Following administration of furosemide and an angiotensin-converting enzyme (ACE) inhibitor, the dog remained free of pleural effusion for 10 months, until he showed severe dyspnea due to chylothorax. Medical therapy was unsuccessful to avoid recurrence of life-threatening pleural chylous effusion. Ligation of the thoracic duct and apposition of an omental pedicle flap were effective in the resolution of pleural chylous leakage.

Results of Transthoracic Esophagotomy Retrieval of Esophageal Foreign Body Obstructions in Dogs: 14 Cases (2000–2004)

The records of 14 consecutive cases of esophageal foreign body obstruction in dogs that had undergone transthoracic esophagotomy for foreign body retrieval were reviewed. Clinical results were considered successful in 13 of 14 dogs. One dog was euthanized at surgery because of the severity of associated thoracic lesions. Clinical signs resolved in the remaining 13 dogs. Two dogs had postoperative complications. One dog developed a pyothorax, and one dog developed a subcutaneous seroma. The overall recovery rate was 93%.

Cisterna Chyli Ablation with Thoracic Duct Ligation for Chylothorax: Results in Eight Dogs

OBJECTIVE

To report use of combined cisterna chyli ablation (CCA) and thoracic duct ligation (TDL) for treatment of spontaneously occurring chylothorax in dogs.

STUDY DESIGN

Retrospective study.

ANIMALS

Eight dogs with chylothorax.

METHODS

TDL was performed through a right caudal intercostal thoracotomy and CCA through a left flank paracostal approach or ventral median celiotomy. Long-term outcome (range, 2-48 months; median, 11.5 months) was evaluated by telephone communication with owners.

RESULTS

Seven dogs were free of clinical signs related to chylothorax at last follow-up (range, 4-48 months; median, 15.5 months). One dog was euthanatized 2 months after surgery because of lack of improvement. No major complications occurred from CCA.

CONCLUSION

CCA and TDL resolved chylothorax in most dogs (88%).

CLINICAL RELEVANCE

CCA combined with TDL may improve the outcome of chylothorax in dogs.