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CJ 1987 S. Karger AG. Basel0014-312X/87/0196-0375S2.75/0Eur. surg. Res. 19: 375-380 (1987)

Experimental Model ofExtended Repeated Partial Hepatectomy in the Dog

A. W. Szaw/owski, B. Saint-Aubert, M.C. Gouttebe/, C. Astre, H. JoyeuxLaboratory of Nuirition and Experimental Oncology, Cancer Institute, University of Montpellier, France

Key Words. Repeated hepatectorny .Liver regeneration .Artificial hepatic assistance

Abstract. The model of extended repeated partial hepatectomy without vascular shunt indogs is presented. It consisted of 65 % initial hepatectomy and after liver regeneration (6-10weeks) repeated hepatectomy. Finally, only the papillary process ofthe caudate lobe (PPC),which constitutes 5 % ofthe initial hepatic mass, was left intacto The most important findingwas an ability of PPC to reconstitute the liver mass which enabled survival without thevascular shunt. After repeated hepatectomy the need for artificial hepatic assistance (paren-leTal nutritional support with frozen plasma) was imperative to offset the effects of acutehepatic failure and to support PPC regeneration.

Several experimental models of extendedhepatectomy aimed at studying the possibili-ties of liver regeneration have been tried out[1,2,6,7,9, 13]. However, in the literaturethere are little data concerning r~peated he-patectomy (RH). The concept of RH hasbeen studied in the rat and shows that re-peated resections do not diminish the regen-erative response [1, 5, 8].

Now, following experimental studies, ma-jor hepatectomies in humans with accepta-ble postoperative mortality can be consid-ered as a possible treatment for liver metas-tases or primary cancer. Unfortunately, theextent of liver resection must not exceed80% of functional parenchyma if regenera-tion is to occur [14]. In the rat, when 90%hepatectomy is performed, no regeneration

is observed in the 10% remaining liver. Themajar finding is an overwhelming steatosiswith a survival ofless than 40 h posthepatec-tomy [12]. However, complete regenerationof the liver has been described in one-stage90% hepatectomized rats only if they weretreated with testosterone [15].

In experimental studies on dogs, when-liver re~ection is extended to 95% (subtotalhepatectomy), the survival usually does notexceed 4 h [2]. This can be prolonged up to100 h using portocaval or mesentericocavalshunt associated with artificial nutritional

support [2, 11].The purpose of this paper was to present

the original model of extended repeated par-tial hepatectomy without vascular shunt indogs. Only the papillary process of the cau-

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376 Sza wlowski/Saint -A ubert/Gouttebel/ Astre/ J oyeux

date lobe (PPC) was left intact (Ieft segrnent 1according to Couinaud [4]), which is thesmallest hepatic lobe and constitutes 5 % ofthe initial hepatic mass.

introduced into jugular vein: one forparenteral nutri-tional support (PNS) ¡rnd the second for plasma infu-sion. Urinary catheter was used to monitor diuresisduring surgery and in the early postoperative periodoAbdomen was reentered through the same verticalmidline incision used for initial hepatectomy. Theadhesions were dissected carefully with electrocoagu-lation to avoid bleeding and the remnant liver wasexposed. Special attention was paid to dissection ofadhesions between the right laterallobe (segment VI +VII) and parietal peritoneum beca use regeneratingliver is very fragile and, if its capsule is damaged, thisconstitutes a source of profuse bleeding. Next, the fis-sure between the right lateral and caudate lobe wasgently dissected and the afTerent vascular pediclesexposed. They were divided, separately ligated (F1ex-idene 2-0), and sectioned. Initially, the caudate lobewas removed. The plane of transsection passedthrough the isthmus situated between the caudatelobe proper (right segment 1) and PPC (left segment1). This is quite a narro;'" passage, measuring 2-3 cmin diameter. In the next step, the right laterallobe wasremoved after downwards traction on the lobe whichexposed the right suprahepatic vein. This vein wasthen ligated (F1exidene 2-0) and sectioned. The livertissue was removed downwards following the venacava, leaving its surfacecompletely denuded. Duringthis 'procedure the small hepatic. veins entering thevena cava were gradually ligated. It is usually themost difficult phase of the operation, which may pro-voke excessive blood loss and possible postoperativedeath. When the resection was completed, only thePPC was left intacto It has its own vascular supply andshould, therefore, remain well vascularized in theabsence of technical error. Abdominal viscera werecarefully examined and no signs of portal hyperten-sion were found (e.g. splanchnic stasis), which ob-viated the need for a vascular shunt. At the end ofsurgery, one peritoneal drain was inserted through theright lower quadrant ofthe abdomen and fixed to theparietal peritoneum. The abdomen is closed in twolayers and the animal placed in a metabolic cage dur-ing recovery and fol!ow-up. The average time of sur-gery was about 120 min. ~

Material and Methods

Eight healthy adult mongrel dogs weighing 14-27 kg and having fasted I dar before surgery wereused in this study. AII the procedures were performedaccording to the principies of atraumatic and aseptictechniques' with dogs under general anesthesia in-duced by intravenous injection of Nesdonal (Thio-pentaJ) -20 mg/kg -followed by tracheal intubation.The ventilation was maintained by respirator whichdelivered a 50 % mixture of oxygen and nitrous oxide.During the operation dogs were perfused with RingerJactate solution (approximately 1,000 mi).

lnitial Hepatectomy (65 %)In the first step a 65 % hepatectomy was per-

formed by the techniques described previously [2, 3,13} (fig. 1). The abdomen was entered through a ver-tical midline incision and self-retaining retractorswere inserted. The folIowing hepatic lobes were ex-posed: left lateral (segment II), left central (segmentIII), quadrate (segment IV) and right central (segmentV). Their afferent vascular pedicles were divided, sep-arately ligated (Flexidene 2-0) and sectioned. Theliver was then retracted downwards and the left trian-gular and gastrohepatic ligaments were incised, takingcare to avoid damaging the left phrenic vein whichindirectly drains the PPC. The corresponding supra-hepatic veins were dissected, ligated (FIexidene 2-0)and sectioned. The lobes were removed, including thegalIbladder, with amputation of liver tissue distal tothe ligature. The abdometi wasclosed without drain-age and the animal placed in a metabolic cage forrecovery. The average time for the procedure wasabout 60 mino No perfusion was needed in fue post-operative period and oral alimentation could startfrom the 1 st postoperative day.

Follow-Up , ..

PNS was undertaken immediately after surgeryand consisted of (per kilogram body weight, per24 hours): 50 mi of water, 7.2 g of glucose, 0.2 g ofnitrogen, electrolytes and trace elements in a nutritive

Repeated HepatectomyDogs were reoperated after a period ofliver regen-

eration, which varied from 6 to 10 weeks (fig. 2). Inthe first step, two silicone catheters (Vygon) were

Repeated Partial Hepatectorny 377

Fig.l. Initial hepatectorny (65%), including thelobes. LL -Left lateral; LC = left central; Q = quad-

Tale; RC -right central and gallbladder; VC -venacava; W& -rernaining liver.

Fig. 2. RH, including the lobes. RL = Right lateral;CP -caudate proper; VC -vena cava; ~ = remainingliver.

mixture supplemented by vitacmins. PNS was contin-ued up to 10-12 postoperative days, after which itwas gradually supplanted by oral feedings. At thesame time, in arder to equilibrate the deficit of coag-ulation factors due to postoperative hepatic failur~,fresh-frozen plasma was infused at gradually decreas-ing doses (per kilogram body weight, per 24 hours):50 mI (including 300 mI at the end of operation) fromday O to day 3, 30 mI from day 4 to day 6 and 16.6 mIfrom day 7 to day 10. Plasma was previously preparedfrom othermongrcl dogs and stored at -80 .C. Ampi-cillin (2 g/day i.m.) was routinely administered up to

the 8th postoperative day.

Results

tive h; at that time the dogs were usuallystanding in their cages. No postoperativemorta1ity after 65% hepatectomy was ob-served. However, there were 3 postoperativedeaths (37.5%) within 48 h following RH: 1dog (No. 1) as a resu1t of intraoperativeb100d 10ss (about 300 mI), and 2 dogs (No. 4and 6) because of increasing posthepatec-tomy.intraperitonea1 b1eeding. B100dy drain-age during the first 4 postoperative days wasobserved in all cases. In the dogs who sur-vived, this b1eeding progressive1y decreasedallowing remova1 of the intraperitonea1drain on day 4.

In arder to follow remnant PPC regenera-tion, the dogs were sacrificed by bo1us intra-venous injection (20 mg) of potassium ch10-ride at different time interva1s (day 8, 16, 30,

The recovery froro anesthesia after 65 %hepatectomy was relatively rapid, whereasafter RH it was prolonged to 3-5 postopera-

378 Sza wlowski/Sain t -A ubert/GouttebeU Astre/ J oyeux

Table l. Repeated partial hepatectorny in the dog: weight of hepatic resection and growth evolution of PPC

No. Weight ofthe dogkg

Initial hepatectomy (65%) RH

weight of hepatic calculated weightresectiona of PPCb

g g

weight of hepatic weight of PPCresection at necropsy

g g/pos.toperative day

12345678

2718

16

17

152016

23-

493333238302222306208412

3826182317

2316

32

440201145253214201265383

130/day le268/day 30164/day 856/day le

276/day 1672/day 2e

346/day 16600/day 45

a The weight of the gallbladder is excluded.b Approximate mathematical calculation of 5 % liver mass according to resection weight at 65 % hepatectomy:

PPC W X 5 . f .. = -; where W = welght O hepatlc resectlon.65

C Postoperative death.

45) chosen arbitrarily. The PPC was re-moved at necropsy and weighed to assess thedegree of regeneration. AlI data concemingthe weight of hepatic resection and growthevolution of PPC are summarized in table l.The different degrees of regeneration ob-served were characterized by rapid growthduring the first 2 weeks. In one case (No. 8)PPC nearly regained the theoretical initialliver mass, i.e., approximately 640 g.

Two dogs (No. 1 and 4) who had diedwithin 24 h after hepatectomy and for whomdifferent degrees of PPC regeneration wereobserved, were used to calculate the approx-imate percentage of RH which varied be-tween 75-80%:

Discussion

The phenomenon ofliver regeneration re-mains of majar interest to surgeons, includ-ing both fundamental research and practicalaspects related to hepatectomy in mano He-patectomy in dog is an excellent model tostudy these problems because, as in man, theoperative technique is based on anatomicaldissection and individual ligation of bloodvessels and bile ducts, supplying the portionof the liver to be resecte<J, while preservingthese structures in ,t!te remnant parto More-ayer, anatomy of the dog liver readily per-mits isolation of the smallest hepatic ana-tomicallobe -PPC (l~t\ segment 1) which inman corresponds to Spiegel's lobe [4] -inarder to study the possibilities of regenera-tion. One-stage subtotal hepatectomy (95%)does not lend itself to such a study beca use

W x 100%(PPC + W) ,RH,%=

where W = weight of hepatic resection at RH.

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379Repeated Partial Hepatectorny

gy, Warsaw, Poland for critically reviewing the rnanu-script and helpful cornrnents. The technical assistancein the laboratory of Mr. M. Brissac and H. Viguierand skillful secretarial assistance of Mrs. B. Pont isgratefully acknowledged as well.

References

survival is limited to 100 h after hepatecto-my. For this reason we adopted an experi-mental model based on RH which could beemployed in mano

Dogs were reoperated after a period of 6-10 weeks of liver regeneration because, asMallet-Guy et al. [9, 10] point out, the majorpart of hepatic parenchyma is reconstitutedduring this time.

The second operation (RH) on dog liverwas a relatively difficult and time-consum-ing procedure necessitating gentle dissectionof anatomical structures and perfect hemo-stasis. In the postoperative period the needfor artificial hepatic assistance (PNS + fro-zen plasma) was imperative to offset theeffects of acute hepatic failure and to sup-port PPC regeneration. The length of artifi-cial hepatic assistance was adapted to thepostoperative course.

The postoperative mortality (37.5%) wasnot only due to technical error (intraopera-tive bleeding) but al so to insufficient regener-ation ofthe PPC after 65O/Q hepatectomy (56and 72 g, respectively), thereby resulting inacute hepatic failure following RH with a rap-idly declining course (dogs No. 4 and 6).

This paper constitutes a preliminary re-port conceming the problems oí RH in thedogo It showed, however, that the smallesthepatic anatomicallobe (5 % of initial hepaticmass) -PPC (left segment 1) -due to thephenomenon of liver regeneration enabledsurvival without vascular shunt. All these as-pects present both practical and theoreticalproblems and warrant further studies.

1 Bucher, N.L.R.: Experimental aspects of hepaticregeneration. New Engl. J. Med. 277: 686-696(1967).

2 Chabal, J.; Metais, B.; Chrzanowska, M.: Servi-tudes anatomiques et chirurgicales des hépatec-tomies expérímentales majeures chez le chien.Lyon chir. 59: 247-257 (1963).

3 Chapuis, Y.; Murat, J.: Foie et voies biliaires, inMurat, Précis de chirurgie expérímentale abdomi-nale et thoracique chez le chien, pp. 93-108 (Mas-son, París 1972).

4 Couinaud, C.: Controlled hepatectomies and ex-posure of the intrahepatic hile ducts. Anatomicaland technical study (Imp. Réun. Chambéry, París1981).

5 Dagradi, A.; Galanti, G.; Brearley, R.: Regenera-tio.n of the liver following multiple resection. Sur-gery 55: 709-713 (1964).

6 Francavilla, A.; Porter, K.A.; Benichou, J.; Jones,A.F.; Starzl, T .E.: Liver regeneration in dogs: mor-phologic and chemical changes. J. surg. Res. 25:405-419 (1978).

7 Gríndlay, J.H.; BolIman, J.L.: Regeneration oftheliver in the dog after partial hepatectomy. Role ofthe venous circulation. Surgery Gynec. Obstet. 94:491-496 (1952).

8 Hays, D.M.; Komi, N.; Lau, R.E.: Influence ofrepeated subtotal hepatic resection on in vitro sur-

.viva! 0f rat liver celIs. Proc. Soco exp. Biol. Med.115:i06-110(1964).

9 MalIet-Guy, P.; Chaneliere, N.; Sterpin, P.; Bouil-let, J.; Espinasse, P.; Barbier, M.; Feroldi, J.; Mal-let-Guy, Y.: Les dix premiersjours de la régénéra-tion hépatique apres hépatectomie majeure chezle chien. Lyon chir. 62: 801-819 (1966).

10 MalIet-Guy, P.; Imbert, J.C.; Jacques, R.: Analyseexpérímentale de la régénération hépatique apreshépatectomie majeure et suppression de I'apportsanguino Lyon chir. 65: 346-352 (1969).

I I Mjahed, A.; Saint-Aubert, B.; Colette, C.; Andrí-guetto, P.C.; Liu, Y.Y.; Astre, C.; Monnier, L.;

Acknowledgement

The authors wish to thank Prof. Janusz J. Szymen-dera, MD, and Prof. Marek P. Nowacki, MD, fromM. Sklodowska-Curie Memorial Institute of Oncolo-

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380 Szawlowski/Sain t -A ubertlGouttebel/ Astre/ J oyeux

Euro surgo15 Vic, P.; Saint-Aubert, B.; Astre, C.; Bones, P.;

Bonardet, A.; Descomps, B.; Humeau, C.; Joyeux,H.: Complete liver regeneration in one-stage 90%heRatectomized rats treated with testosterone.Hepatology 2.: 247-248 (1982). Can H.

Spleen:Demonstr:

Received: April 29, 1985Accepted: November 21, 1985 B. Nordli1í

INSERM U

Joyeux, H.: Etude comparative de trois shuntsporto-systémiques apres hépatectomie de 65 %chez le chien. J. Chir., Paris 120: 397-402(1983). -

12 Saint-Aubert, B.; Vic, P.; Brissac, C.; Bories, P.;Humeau, C.; Joyeux, H.; Solassol, C.: Régénéra-tion hépatique chez le rat apres hépatectomie sub-totale (90%) traité a la testostérone. C.r. Acad.Sci., Paris 291: 653-655 (1980).

13 Sigel, B.: Partial hepatectomy in dogo Archs Surg.87: 100-103 (1963).

14 Starzl, r.E.; Putnam, C. W.; Groth, C.G.; Corroan,J.L.; Taubman, J.: Alopecia, ascites and incom-plete regeneration after 85 to 90% liver resection.Am. J. Surg. 129: 587-590 (1975).

Prof. H. JoyeuxDepartment of Surgery and NutritionCancer InstituteF-34094 Montpellier Cedex (France)

Key Word:

multiplicatio,

Abstract. ~tion into the :

Hepatocytesinjected into

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, . The transcytes into ththepatic failuJrats [3, 11,strated thatsurvlve overtaining sorne15, 17]. To a1