Journal oflmmunological Methods, 21 (1978) 383--387 © Elsevier/North-Holland Biomedical Press
383
MICROSURGICAL CANNULATION OF THE THORACIC DUCT IN CATS. TECHNICAL NOTE SKIP JACQUES *, C. HUNTER SHELDEN, ROBERT H. PUDENZ and JEAN FORT Department of Neurosurgery, Huntington Memorial Hospital, Pasadena, CA and Huntington Institute of Applied Medical Research, Pasadena, CA 91105, U.S.A.
(Received 23 November 1977, accepted 14 January 1978)
The authors describe a new technique for the microsurgical cannulation of the thoracic duct. A small silastic tube is utilized which can be joined to a subcutaneously implanted one-way flow, CSF, Ommaya-type ** reservoir. External drainage is avoided. No deletion or alteration of major venous channels occurs. Lymph collection is accomplished by tapping the subcutaneous reservoir with a small-bore needle.
INTRODUCTION T h e c o l l e c t i o n o f t h o r a c i c d u c t e f f l u e n t is a w i d e l y u s e d e x p e r i m e n t a l p r o c e d u r e . It has f o u n d a p p l i c a t i o n in h e m a t o l o g y , renal a n d g a s t r o i n t e s t i n a l physiology, experimental biochemistry, and particularly immunology. Multiple m e t h o d s h a v e b e e n r e p o r t e d f o r surgical a p p r o a c h t o , a n d e x p o sure of, t h e t h o r a c i c d u c t in animals a n d m a n , including a m e t h o d f o r t h e c r e a t i o n o f a t h o r a c i c d u c t - v e n o u s fistula (Beschel and M c C a r t h y , 1 9 6 4 ; Raju et al., 1 9 7 4 ; D u m o n t , 1 9 7 5 ; K e m p e a n d B l a y l o c k , 1977). We have f o u n d n o r e p o r t s d e s c r i b i n g t h e a n a t o m y a n d surgical t e c h n i q u e in cats w h i c h we h a v e f o u n d t o be an ideal a n i m a l m o d e l f o r t h o r a c i c d u c t l y m p h collection. A m i c r o s u r g i c a l t e c h n i q u e is essential b e c a u s e o f t h e small caliber o f t h e d u c t in this species. This r e p o r t is p r o m p t e d b y t h e i m p o r t a n c e o f t h o r a c i c d u c t l y m p h collect i o n in m o d e m b i o l o g y c o u p l e d w i t h t h e a d v a n t a g e s o f this t e c h n i q u e in smaller a n d less e x p e n s i v e l a b o r a t o r y animals, a l t h o u g h t h e t e c h n i q u e w o u l d be a p p l i c a b l e t o larger animals also.
* Present address: Division of Biology, California Institute of Technology, Pasadena, CA, U.S.A. Address reprints to S. Jacques, M.D., Huntington Institute of Applied Medical Research, 734 Fairmount Avenue, Pasadena, CA 91105, U.S.A. Supported in part by a grant from the Wright Foundation. ** The authors are indebted to the Heyer-Schulte Corporation, Goleta, CA for providing the Ommaya reservoirs and shunt components.
384 METHOD
A cat is injected subcutaneously in both hind paws with 5 ml of a 2% sterile solution of Evans blue mixed equal parts with 2% Lidocaine, 18 h before surgery. This greatly enhances later lymph channel identification since it imparts a sky blue color to the lymph. The dye becomes bound to the lymph protein. The animal is premedicated prior to surgery with acepromazine, anesthetized with sodium thiamylal i.v., intubated and placed in the supine position with the head extended and rotated minimally to the right. Two ml of 20% glucose solution are given intravenously to increase thoracic duct lymph volume (Cain et al., 1947). An S-shaped skin incision is made in the midline below the sternal notch (Fig. 1). Dissection is carried deep exposing the lateral side of the stemomastoid muscle and the pectoralis major muscle, whose fibers course at right angles to the skin incision (Fig. 2). The area beneath the pectoralis muscle is freed using a small cottonoid to avoid puncturing the pleura. The muscle fibers are cut with scissors, thus exposing the upper anterolateral area of the thoracic cage. The incision should expose the margin of the first rib, which
Fig. 1. Skin incision is m a d e S-shaped f r o m b e l o w sternal n o t c h to a p p r o x i m a t e c o u r s e of e x t e r n a l jugular vein s u p e r i o r l y .
385 P e c t o r o l i s m.
M u s c l e cut
Left sternocleidomastoid
m. ~ . . . .
Fig. 2. Pectoralis fibers are cut exposing trifurcation of subclavian, external jugular and innominate veins.
should be located by palpation. The subclavian vein passes mesially just cephalad to the first rib. Retraction sutures (1 or 2) should be placed in lateral aspect of anterior scalenus muscle which can be seen running parallel to and just medial to the large jugular vein. The sutures facilitate mesial retraction of the muscle (Fig. 3). At this stage of dissection the major structures to be identified are the external jugular, subclavian and innominate veins, the superior surface of the first rib, the dome of the pleura just mesial to it and the scalenus muscle. Once these structures are located the surgeon should use the surgical microscope for further dissection. With the microscope, numerous blue linear structures, the lymphatic ducts, can be clearly seen. Dissection is continued deep between the scalenus muscle and the external jugular vein remaining close to the muscle. Dissection should be done using two small jeweler's forceps so that one can grasp the fine areolar-like tissue and separate this tissue by gently pulling it apart. A key structure is the vagus nerve lying along the anterolateral margin of the muscle. Dissection need go no deeper. Laterally there may be numerous sky blue colored lymph channels. Usually, the thoracic duct entrance into the jugular vein is on the mesial superficial aspect of the vein, but there are m a n y varia-
386
Fig. 3. Scalene muscle is retracted medially facilitating exposure of thoracic duct. Note relationship of vagus nerve to thoracic duct. tions. The mo s t f r e q u e n t variation of the main d u c t t r u n k is in its course upward f r o m the t hor ax; first lateral to the jugular vein, then passing beneath it and curving superficially on the mesial aspect to its poi nt of entrance. Occasionally the superior branch joins with the main duct from below and enters t he jugular vein as a single channel. The ducts are small, of t e n only 1--2 m m O.D., and ext rem el y thin-walled. The thoracic d u c t has one characteristic that aids the surgeon, namely, a t r e m e n d o u s capability to dilate. A s m a l l Scoville clip applied to the duct and left in place f o r 5--7 min results in marked dilatation of the segment proximal to the clip. Th e duct should be cannulated before removing the clip. As the cannula tip enters the duc t it will pass at most 1.5 cm before it strikes the first valve. Valves give less t r oubl e if the duct has been allowed t o dilate freely before cannulation. Even with a dilated duct, manipulation, gentle pressure and patience are required to pass the tip of the cannula t w o or more centimeters d o w n the duct. Our shunting system consists o f a silastic t ube 0.7 m m O.D. and 0.3 m m I.D. stabilized with curled wire support. The tip is firm and slotted. The solid distal part o f the tip greatly aids the initial passage of the cannula into the duct. The tu b e leads to an O m m a y a reservoir, placed subcutaneously in the neck. The entire system is heparinized.
387
The reservoir size most applicable in cats has a capacity of --1 ml (larger reservoirs could be used but would require creating a larger subcutaneous pocket). The reservoir is made of silicone with a flat base and self-sealing dome which can be punctured m a n y times with a small-bore needle. The diameter of the base is 1.5 cm with a side-inlet tubing for connection to the silastic cannula in the thoracic duct. Successful cannulation and patency for up to 6 months has been achieved in 25 animals. There have been no infection problems. Animals are given penicillin i.m. daily (100,000 u/kg) for the first 4 days following surgery, and the wounds are irrigated with a solution of Bacitracin ® (5000 p in 10 ml of saline) prior to skin closure. Utilizing this technique we have been able to collect normal lymph as often as desired for several m o n t h s by tapping the subcutaneous reservoir with a small-bore needle. During dissection, prior to inserting the cannula, there is evidence of multiple points of entrance of lymph channels into the vein. The openings probably allow the lymph to enter into the jugular vein in adequate amounts in spite of the cannulated opening into one of the larger channels. Urine o u t p u t postoperative has varied from 20 to 30 ml/kg/ day and hematocrits have ranged from 25 to 46%. None of our animals has shown evidence of lymph deprivation. REFERENCES Beschel, H. mid M.J. McCarthy, 1964, Can. J. Surg. 7,346. Cain, J.C., J.H. Grindlay, J.L. Bollman, E.V. Flock and F.C. Mann, 1947, Surg. Gynecol. Obstet. 85, 559. Dumont, A.E., 1975, Am. J. Med. Sci. 269,292. Kempe, L.G. and R. Blaylock, 1977, J. Neurosurg. 47, 86. Raju, S., W.C. Tompkins and J.H. Conn, 1974, Am. J. Surg. 127,256.
383
MICROSURGICAL CANNULATION OF THE THORACIC DUCT IN CATS. TECHNICAL NOTE SKIP JACQUES *, C. HUNTER SHELDEN, ROBERT H. PUDENZ and JEAN FORT Department of Neurosurgery, Huntington Memorial Hospital, Pasadena, CA and Huntington Institute of Applied Medical Research, Pasadena, CA 91105, U.S.A.
(Received 23 November 1977, accepted 14 January 1978)
The authors describe a new technique for the microsurgical cannulation of the thoracic duct. A small silastic tube is utilized which can be joined to a subcutaneously implanted one-way flow, CSF, Ommaya-type ** reservoir. External drainage is avoided. No deletion or alteration of major venous channels occurs. Lymph collection is accomplished by tapping the subcutaneous reservoir with a small-bore needle.
INTRODUCTION T h e c o l l e c t i o n o f t h o r a c i c d u c t e f f l u e n t is a w i d e l y u s e d e x p e r i m e n t a l p r o c e d u r e . It has f o u n d a p p l i c a t i o n in h e m a t o l o g y , renal a n d g a s t r o i n t e s t i n a l physiology, experimental biochemistry, and particularly immunology. Multiple m e t h o d s h a v e b e e n r e p o r t e d f o r surgical a p p r o a c h t o , a n d e x p o sure of, t h e t h o r a c i c d u c t in animals a n d m a n , including a m e t h o d f o r t h e c r e a t i o n o f a t h o r a c i c d u c t - v e n o u s fistula (Beschel and M c C a r t h y , 1 9 6 4 ; Raju et al., 1 9 7 4 ; D u m o n t , 1 9 7 5 ; K e m p e a n d B l a y l o c k , 1977). We have f o u n d n o r e p o r t s d e s c r i b i n g t h e a n a t o m y a n d surgical t e c h n i q u e in cats w h i c h we h a v e f o u n d t o be an ideal a n i m a l m o d e l f o r t h o r a c i c d u c t l y m p h collection. A m i c r o s u r g i c a l t e c h n i q u e is essential b e c a u s e o f t h e small caliber o f t h e d u c t in this species. This r e p o r t is p r o m p t e d b y t h e i m p o r t a n c e o f t h o r a c i c d u c t l y m p h collect i o n in m o d e m b i o l o g y c o u p l e d w i t h t h e a d v a n t a g e s o f this t e c h n i q u e in smaller a n d less e x p e n s i v e l a b o r a t o r y animals, a l t h o u g h t h e t e c h n i q u e w o u l d be a p p l i c a b l e t o larger animals also.
* Present address: Division of Biology, California Institute of Technology, Pasadena, CA, U.S.A. Address reprints to S. Jacques, M.D., Huntington Institute of Applied Medical Research, 734 Fairmount Avenue, Pasadena, CA 91105, U.S.A. Supported in part by a grant from the Wright Foundation. ** The authors are indebted to the Heyer-Schulte Corporation, Goleta, CA for providing the Ommaya reservoirs and shunt components.
384 METHOD
A cat is injected subcutaneously in both hind paws with 5 ml of a 2% sterile solution of Evans blue mixed equal parts with 2% Lidocaine, 18 h before surgery. This greatly enhances later lymph channel identification since it imparts a sky blue color to the lymph. The dye becomes bound to the lymph protein. The animal is premedicated prior to surgery with acepromazine, anesthetized with sodium thiamylal i.v., intubated and placed in the supine position with the head extended and rotated minimally to the right. Two ml of 20% glucose solution are given intravenously to increase thoracic duct lymph volume (Cain et al., 1947). An S-shaped skin incision is made in the midline below the sternal notch (Fig. 1). Dissection is carried deep exposing the lateral side of the stemomastoid muscle and the pectoralis major muscle, whose fibers course at right angles to the skin incision (Fig. 2). The area beneath the pectoralis muscle is freed using a small cottonoid to avoid puncturing the pleura. The muscle fibers are cut with scissors, thus exposing the upper anterolateral area of the thoracic cage. The incision should expose the margin of the first rib, which
Fig. 1. Skin incision is m a d e S-shaped f r o m b e l o w sternal n o t c h to a p p r o x i m a t e c o u r s e of e x t e r n a l jugular vein s u p e r i o r l y .
385 P e c t o r o l i s m.
M u s c l e cut
Left sternocleidomastoid
m. ~ . . . .
Fig. 2. Pectoralis fibers are cut exposing trifurcation of subclavian, external jugular and innominate veins.
should be located by palpation. The subclavian vein passes mesially just cephalad to the first rib. Retraction sutures (1 or 2) should be placed in lateral aspect of anterior scalenus muscle which can be seen running parallel to and just medial to the large jugular vein. The sutures facilitate mesial retraction of the muscle (Fig. 3). At this stage of dissection the major structures to be identified are the external jugular, subclavian and innominate veins, the superior surface of the first rib, the dome of the pleura just mesial to it and the scalenus muscle. Once these structures are located the surgeon should use the surgical microscope for further dissection. With the microscope, numerous blue linear structures, the lymphatic ducts, can be clearly seen. Dissection is continued deep between the scalenus muscle and the external jugular vein remaining close to the muscle. Dissection should be done using two small jeweler's forceps so that one can grasp the fine areolar-like tissue and separate this tissue by gently pulling it apart. A key structure is the vagus nerve lying along the anterolateral margin of the muscle. Dissection need go no deeper. Laterally there may be numerous sky blue colored lymph channels. Usually, the thoracic duct entrance into the jugular vein is on the mesial superficial aspect of the vein, but there are m a n y varia-
386
Fig. 3. Scalene muscle is retracted medially facilitating exposure of thoracic duct. Note relationship of vagus nerve to thoracic duct. tions. The mo s t f r e q u e n t variation of the main d u c t t r u n k is in its course upward f r o m the t hor ax; first lateral to the jugular vein, then passing beneath it and curving superficially on the mesial aspect to its poi nt of entrance. Occasionally the superior branch joins with the main duct from below and enters t he jugular vein as a single channel. The ducts are small, of t e n only 1--2 m m O.D., and ext rem el y thin-walled. The thoracic d u c t has one characteristic that aids the surgeon, namely, a t r e m e n d o u s capability to dilate. A s m a l l Scoville clip applied to the duct and left in place f o r 5--7 min results in marked dilatation of the segment proximal to the clip. Th e duct should be cannulated before removing the clip. As the cannula tip enters the duc t it will pass at most 1.5 cm before it strikes the first valve. Valves give less t r oubl e if the duct has been allowed t o dilate freely before cannulation. Even with a dilated duct, manipulation, gentle pressure and patience are required to pass the tip of the cannula t w o or more centimeters d o w n the duct. Our shunting system consists o f a silastic t ube 0.7 m m O.D. and 0.3 m m I.D. stabilized with curled wire support. The tip is firm and slotted. The solid distal part o f the tip greatly aids the initial passage of the cannula into the duct. The tu b e leads to an O m m a y a reservoir, placed subcutaneously in the neck. The entire system is heparinized.
387
The reservoir size most applicable in cats has a capacity of --1 ml (larger reservoirs could be used but would require creating a larger subcutaneous pocket). The reservoir is made of silicone with a flat base and self-sealing dome which can be punctured m a n y times with a small-bore needle. The diameter of the base is 1.5 cm with a side-inlet tubing for connection to the silastic cannula in the thoracic duct. Successful cannulation and patency for up to 6 months has been achieved in 25 animals. There have been no infection problems. Animals are given penicillin i.m. daily (100,000 u/kg) for the first 4 days following surgery, and the wounds are irrigated with a solution of Bacitracin ® (5000 p in 10 ml of saline) prior to skin closure. Utilizing this technique we have been able to collect normal lymph as often as desired for several m o n t h s by tapping the subcutaneous reservoir with a small-bore needle. During dissection, prior to inserting the cannula, there is evidence of multiple points of entrance of lymph channels into the vein. The openings probably allow the lymph to enter into the jugular vein in adequate amounts in spite of the cannulated opening into one of the larger channels. Urine o u t p u t postoperative has varied from 20 to 30 ml/kg/ day and hematocrits have ranged from 25 to 46%. None of our animals has shown evidence of lymph deprivation. REFERENCES Beschel, H. mid M.J. McCarthy, 1964, Can. J. Surg. 7,346. Cain, J.C., J.H. Grindlay, J.L. Bollman, E.V. Flock and F.C. Mann, 1947, Surg. Gynecol. Obstet. 85, 559. Dumont, A.E., 1975, Am. J. Med. Sci. 269,292. Kempe, L.G. and R. Blaylock, 1977, J. Neurosurg. 47, 86. Raju, S., W.C. Tompkins and J.H. Conn, 1974, Am. J. Surg. 127,256.
