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Medium chain triglycerides in the management of chylous fistulae following

neck dissection

I. C. Martin, L. H. Marinho, A. E. Brown. D. McRobbie

Muxillqfacial Unit, Queen Victoria Hospital, East Grinstead, West Sussex

SUMMARY.

The physiology of fat absorption and its relevance to chylous fistula following neck dissection is

discussed. Three patients with postoperative chylous fistulae were successfully managed conservatively using

medium chain triglycerides as a substitute for normal dietary fat.

INTRODUCTION

Persistent chylous fistula in the neck following neck

dissection i s a relatively uncommon complication.

Conley (1979) reported an incidence of l-2% with

25% of cases occurring on the right. Two to four

litres a day of chyle may be produced and drain

through the fistula. This can pose particular problems

with maintaining fluid balance and nutrition in the

critical postoperative phase following major surgery

(Conley. 1979). In addition reduced immunity due to

loss of leucocytes may render the patient more suscep-

tible to postoperative infection.

The management of chylous fistulae can be con-

servative or operative. Operative intervention is usu-

ally undertaken only when persistently large volumes

of fluid loss cannot adequately be replaced or when

there is a problem in maintaining adequate nutrition.

Conservative management has traditional ly consisted

of a fat restricted diet. This reduces the volume of

chyle produced, thereby facilitating spontaneous clos-

ure of the fstula, however this approach leads to a

reduction in caloric intake during the period of

maximum catabolism. An alternative is to use total

parenteral nutrition, but this is not without its compli-

cations, and in some ser ies has been shown to be of

doubtful benefit in actually reducing volumes of chyle

produced (Puntis

et al., 1987).

Most dietary fat is composed of long chain tr i-

glycerides. These are absorbed by the action of intesti-

nal lipases which break down triglyce rides to their

component fatty acids and glycero l. Long chain fatty

acids are then packaged into chylomicrons which are

absorbed into the lymphatic system and drain via the

thoracic duct into the venous system. However,

medium chain fatty acids of six to ten carbon chain

length are absorbed directly into the portal system

thus by-passing the lymphatics (Fig. I).

The use of medium chain triglycerides as a substi-

tutc for normal dietary fat has been shown to be

effective in reducing the volume of chyle produced in

chylothorax (Gershanik

et al.,

1974; Van Aerde

et ul.,

1984; Puntis

et

u/., 1987; Laing & Spitz, 1989). This

paper describes the use of medium chain triglycerides

in the management of 3 patients with postopcrativc

chylous fistulae following neck dissection.

Case reports

Case 1

A 4 year-old female presented with a T2N1 MO squamous

ccl1 carcinoma of the r ight lateral border of the tongue. A

r ight functional neck dissection and en-bloc hemigloss-

cctom v was performed. The defect was reconstructed using

a fasclo-cutaneous radial forearm free flap. Whilst under-

going postoperative adjuvant radiotherapy, a mctas tatic

node wa s detected in the contra- lateral neck, and a left

functional neck dissection was therefore performed. The

patient was discharged on the 7th postoperative day. but

returned the following day with a fluid collection in the left

neck. On aspiration this proved to be chylc. Rcpeatcd

aspirations were therefore performe d, and an oral diet with

medium chain tr iglycer ide (MCT) substi tute was com-

mcnc cd. Th e MC T formulation is shown in Table I. The

effect upon chyle production is shown in Figure 2.

Case 2

A 40-year-old male presented with a T4NOM O squamous

cel l carcinoma of the r ight mandibular alveolus. He had

received external be am radiotherapy 7 years previously as

the pr imary treatment for a squamous cel l carcinoma of

the r ight lateral border of the tongue. There was no evidence

of recurrent disease at this si te. A r ight functional neck

dissection and en-bloc hcmi-mandibulcctomy was pcr-

formed. The defect was reconstructed with a composite

ossco-fascial for&m flap. On the 12th postoperative day

a mi lky discharge was noted from the drain si te and

chemical analysis confi rmed that this was chyle. Nasogastr ic

feeding with M CT was comme nced. The effects upon chyle

volume and triglyceride levels arc shown in Figure 3 .

Table I - Fatty acid composition of Liquigcn (Scientific Hospital

Supplies) Medium Chain Triglyccridc preparation. 100 ml of the

emulsion gives 416 Kcal

Caproic Acid (Ch) 1. I

CaprTlic Acid (C8) 8 I I

Caprlc Acid (CIO) 15.7

Laurie Acid (C12) 2. I

236

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Medium chain tr iglycer ides

237

Intestinal lumen

Fig. 1 - Physiology of tr iglycer ide absorption. Medium chain tr iglycerides pass directly into the portal system avoiding the lymphatics.

Volumetml)

100

80

60

40

20

0

0 5 10 15 20 25

Post-op. days

Fig. 2 - Case I. Chyle drainage ceased 10 days after substi tut ion of

MC T for dietary fa t given oral ly.

Volume(mlj TriglycerideImmoliL

1000

r

-.-

MCT

800

- - Triglyceride

4

I

- J

600

-0 5 10

15 20 25

30.

Post-op. days

Fig. 3 - Cas e 2. Triglyceride levels fell rapidly following the

insti tut ion of nasogastr ic feeding with MC T. Chyle drainage

ceased I4 days fol lowing the commencem ent of this regime

Case 3

A 24-year-old patient presented with a T2N2M O squamous

cel l carcinoma of the r ight f loor o f mouth and ventral

surface of tongue. A r ight radical neck dissection and en-

bloc resection of the tumour was pcrformcd. The defect

was reconstructed using a radial forearm fascia-cutaneous

hap. Postoperative recovery was unremarkable unti l the

8th day when a mi lky discharge was noted from the drain

si te. The f luid was col lected in a colostomy bag and

chemical analysis confi rmed the cl inical impression of chyl-

ous f istula. MCT nasogastr ic feeding was commen ced after

48 h. Figure 4 shows the effect of ,MCT on chyle volumes

and triglyceride levels.

DISCUSSION

The rationale for nutritional intervention in abnormal

chyle drainage i s to prevent malnutrition and to

diminish chyle production and flow. The major con-

stituents of dietary lipid are long chain triglycerides,

most of which, once absorbed, are transported by the

lymphatic system. The basal rate of lymph flow

(1.38 ml/Kg/Hr) can increase tenfold following a fatty

meal. A diet in which the fat content is comprised

solely of medium chain trig lycerides leads to low flow

of achylous lymph. The precise mechanism by which

MCT reduces chyle volume is unclear, however it

would seem reasonable to speculate that th is could

VolumeCmlj

300 - - --.

-.

MC, I

250

Triglyceridebnmol/LI

.-

- -60

r---

1

Volume I

50

i - Triglycetide i

I40

I

30

20

10

,L- __.~.__ .\_ -A.- \ ; I?-( ,

0 5 10 15 20 25 30

35

Post-op. days

Fig.

4 - Case 3. Tr iglycer ide levels fel l immediately fol lowing the

insti tut ion of the MC T regime. The chylous leak had resolved

completely I5 days later.

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238

British Journal of Oral and Maxillofacial Sureerv

be explained by the reduction in chylomic ron pro-

duction resulting from MCT bypassing the lymphatic

pathway and being direc tly absorbed into the portal

system. We are unable to explain the transient increase

in Triglyceride level which occurred immediately fol-

lowing the introduction of MCT in case 2 but this

might suggest that MCT has a direct inhibi tory effect

upon chyle production. MCT maintains adequate

calor ic intake whilst at the same time creating favour-

able conditions for the spontaneous closure of a

chylous fistula.

In all three patients the listula had closed within 2

weeks of commencing the feeding regime in which

MCT was used to replace dietary fat rcquiremcnts.

Whi lst little information is available regarding the

length of time taken for fistulae to close spon-

taneously without any dietary intervention, Crumley

and Smith (1976) reported a series of 12 cases in

which chyle drainage persisted for up to 28 days

when surgical intervention was not undertaken.

The use of MCT together with protein, metabolic

mineral mixture, folic acid and multivitamin sup-

plements, proved to be a satisfactory conservative

approach to the difficult problem of postoperative

chylous listula.

References

Co&y. J. J. (I 979). Com piicntions

of

Head und Nerk Surgery.

pp. 30-3 I Philadelph ia: W. B. Saunders.

Crumley. R. L. & Smith. J. D. (1976). Postoperative chylous hstula

prevention and management. Ixvpga.scope. 86,804.

Gershanik. J. J.. Jonsonn, H. T., Rio@. D. A. & Packer. R. M.

(1974). Dietary management of neonatal chylothorax.

Pediurrics, 53,400.

Laing, J. H. E. & Spitz. L. (1989). Chylothorax and delayed

paraparesis in an infant following improper use of a front seal

belt. Brilish Journal of Surgery, 76, 129.

Puntis, J. W. L.. Roberts, K. D. & Handy, D. (1987). IIow should

chylolhorax bc man aged ? Archives of Discuses in Child hood.

62, 593.

Van Aerde, J.. Campbell, A. N.. Smyth. J. A., Lloyd, D. &

Bryan. H. (1984). Sponta neous chylothorax in newborns.

American Journal

of

Discuses of Childhood, 138,96 I,

The Authors

1. C. Mart in FDSRCS, ARCS

Senior Registrar in Maxillofacial Surgery

L. H. Marinho Xl , FFDRCSI

Visiting Registrar in Maxihofacial Surgery

A. E. Brown FDSRCS, ERCS

Consultant Maxillofaacial Surgeon

D. McRohhie BPharm, MRPharm S

Clinical Services Pharmacist

Queen Victoria Hospital

East Grinstead

West Sussex RH I9 3DZ

Correspondence and requests for offprints to Mr 1. C. Martin ,

Consultant Maxillofacial Surgeon, Sunderland District General

IIospital. Kayll Road, Sunderland SR4 7TP

Paper received I June I992

Accepted I4 December 1992