Tonsillectomy and poliomyelitis

TONSILLECTOMY AND POLIOMYELITIS I I . FREQUENCY OF BULBAR PARALYSIS, 1944-1949

MORRIS SIEGEL,M.D., MORRISGREENBERG,M.D., AND M. CATI-IER[NEMAGEE, M.D. NEW YORK, N. Y. sis following tonsillectomy. Two methods of approach were considered. One was based on an analysis of incidence of bulbar poliomyelitis in tonsillectomized and nontonsillectomized groups f r o m data collected in 1949. I t was Blear at the onset oi t h a t study t h a t poliomyelitis was too uncommon, even during an epidemic year, to ac cumulate sufficient data for reliable deductions on such specific incidence :from a survey conducted in 1949 alone. The second a p p r o a c h to the problem was based on an analysis of the pereentage distribution oi clinical types of poliomyelitis following tonsillee tomy. This has been the conventional method in the absence of sufficient data on the size of the tonsillectomized population at risk, and was employed in the present study.

P R E V I O U S report, evidence of I NanA increase in the incidence of poliomyelitis s h o r t l y a f t e r tonsillectomy was presented. 1 I n the p r e s e n t study, the clinical types of poliomyelitis encountered in post-tonsilleetomized eases were investigated. The possible relationship of b u l b a r p a r a l y s i s to tonsillectomy was noticed as f a r b a c k as 1910. 2 I n 1928 and 1929, two reports were made on the large p e r c e n t a g e of post-tonsillectomized cases of poliomyelitis with b u l b a r paralysis. 3, * A f t e r 1929, t h e r e were n u m e r o u s accounts of single or multiple eases of b u l b a r p a r a l y s i s occ u r r i n g s h o r t l y a f t e r tonsillectomy2 -2a Since 1940, however, r e p o r t s of surveys on the incidence of poliomyelitis in tonsillectomized populations, m a d e chiefly b y laryngologists, have stressed the infrequency of ctinieal infection following o p e r a t i o n and b y inference the r a r i t y of b u l b a r p a r a l y s i s in such eases.a, refs. 1-13 Consequently, considerable confusion has arisen and doubt has been expressed over the relationship of b u l b a r poliomyelitis to recent tonsillectomy even t h o u g h the association h a d seemed so well established on clinieaV -~ and e x p e r i m e n t a l grounds, e4 I t therefore became necessary to reexamine the problem of bulbar paralyF r o m t h e B u r e a u of P r e v e n t a b l e D i s e a s e s , N e w Y o r k C i t y D e p a r t m e n t of H e a l t h .

METHOD

The sources of data examined were the records of cases of poliomyelitis reported to the H e a l t h D e p a r t m e n t of the City of New Y o r k p r i o r to 1950. A review of the record cards revealed t h a t a query on recent tonsillectomy was carried on all cards in use since 1944. The present s t u d y was therefore limited to all cases r e p o r t e d from 1944 to 1949, inclusive. Records of cases reported before 1944 were considered incomplete with respect to in-

548

SIEGEL ET AL. :

TONSILLECTOMY AND POLIOMYELITIS.

formation on tonsillectomy and were omitted from the study. The six-year period from 1944 to 1949 began and ended with epidemics in 1944 and 1949. The in~tervening years, from 1945 to 1948 inclusive, were nonepidemic. The epidemic and nonepidemic years were treated separately in preliminary tabulations and then combined to detelTMne the outcome in all reported cases. From 1944 to 1949, inclusive, 6,524 cases of poliomyelitis and 392 deaths were reported in New York City (Table I). TABLE I CASES

YEA~S 1944 1945 1946 1947 1948 1949

I~O. 1,890 545 716 224 703 2,446 6,524

I~ATE pER I00,000 24.6 7.1 9.2 2.9 8.7 30.0 13.8

DEATHS CASE FATALITY NO. (% ) 102 5.4 37 6.8 38 5.3 10 4.5 26 3.7 179 7.3 392 6.0

The reported cases included paralytic and nonparalytic forms of the disease. For purposes o~ analysis, the paralytic forms were broken down into spinal and bulbar types. The former consisted of cases with paralysis of spinal nerves only; the latter of all other paralytic cases commonly clasTABLE I I .

YEAR

II.

549

sifted as bulbar or bulbo-spinal. Cases without evidence of paralysis or muscle weakness were called nonparalytic. The so-called abortive forms of poliomyelitis lacked the necessary diagnostic criteria to be considered definite clinical cases of poliomyelitis and were currently excluded from the files of reported eases along with many misdiagnosed eases. On the average, the excluded cases comprised about 20 per cent of the total tentatively reported each year as poliomyelitis. The findings were obtained by trained diagnosticians who examined all patients either at home or in the hospital usually within twenty-four hours after the illness had been reported. In most cases, additional data on affected parts of the body were obtained during convalescence. RESULTS

A summary of the clinical ~ypes of poliomyelitis found in reported cases by year of onset is given in Table II. The percentage distribution of the various clinical types differed somewhat by year of onset. The differences between epidemic and nonepidemie years were not considered statistically significant. The average percentage for the entire period and the highest

CLINICAL TYPES OF POLIO~IYELITIS I~EPORTED IN NEW YORK CITY (1944-1949)

OF ONSET 1944 ~ 1945t 1946t 1947t 1948t 1949 ~ Total ~Epidemic y e a r s ~Nonepidemle years

TOTAL 1,890 545 716 224 703 2~446 6,524 4,336 2,188

BULBAR CASES I % 274 14.5 91 16.7 144 20.1 24 10.7 101 14.4 392 16.0 1,026 15.7 666 15.4 360 16.5

SPINAL -CASES I. % 892 47.2 249 45.7 324 45.2 91 40.6 332 47.2 1~109 45.3 2,997 45.9 2,001 46.1 996 45.5

NONPARALYTIC CASES I % 724 38.3 205 37.6 248 34.7 109 48.7 270 38.4 945 38.7 2,501 38.4 1,669 38.5 832 38.0

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group at any time was 30.1 per cent in 1945 for patients 20 years and over.

and lowest percentages in single years are listed in Table I I I .

A m o n g the reported cases described above, a history of tonsillectomy within one year of the onset of poliomyelitis was noted in 194 cases. These formed the basis of the present study.

TABLE I i I TYPE OF DISEASE Bulbar Spinal Nonparalytie

PEI~CENTAGES AVERAGEI I~IGH I 15.7 20.1 45.9 47.2 38.4 48.7

LOW 10.7 40.6 34.7

Their distribution by monthly intervals between operation and onset in each year of occurrence is given in Table V.

The types of paralysis also varied with the age group as shown in Table IV. The percentage of bulbar cases was lowest in the youngest age group. I t varied from 10.6 per cent at 0 to 4 years to 18.8 per cent at 10 years and over, with an average of 15.7 for the six-year period. TABLE IV.

The number of post:tonsilleetomized cases each year was related in part to the total number reported, being largest for the epidemic years of 1944 and 1949 and smallest in nonepidemie

CLINICAL [PYPES OF POLIOMYELITIS REPORTED FROM 1944 TO 1949 BY AGE GROUP BULBAR

A~E

TOTAL

0- 4 5- 9 10-14 15-19 20 and over Total

1,700 2,209 1,373 572 670 6,524

CASE q 180 355 258 107 126 1,026

SPINAL

% 10.6 16.1 18.8 18.7 18:8 15.7

CASE I 1,035 859 510 27] 322 2,997

.

%

NONPARALYTIC

CASE I

60.9 38.9 37.1 47.4 48.1 45.9

485 995 605 194 222 2,501

% 28.5 45.0 44.1 33.9 33.] 3K4

TABLE V MONTHLY

Y E A R OF ONSET

1944 ]945 ]946 1947 1948 1949 Total Percentage

TOTAL

59 15 20 2 24 74 194 1.0(}

0-1

INTERVAL BETWEEN OPERATION AND ONSET OF P O L I O M Y E L I T I S

1

10 3 4 1 6 6 30 15.5

F r o m the foregoing description of reported easesl it was seen that the percentage of bulbar, spinal, and nonparalytic eases observed from 1944 through 1949 differed somewhat by year of onset and age group. The frequency of bulbar paralysis tended to be lower among those under 10 years of age t h a n in older groups. The maximum percentage in any age

1-2

e-3

13 3 5 0 4 7 32 16.5

7 2 2 0 2 21 34 17.5

L

3-6 22 5 8 0 9 35 79 40.7

L

6-12 7 2 1 ] 3 5 19 9.8

years, particularly in 1947 when the incidence in the city was lowest. I n each year, one or more eases occurred within a month after operation, the total for the six-year period being t h i r t y eases or 15.5 per cent. Almost half of the eases had their onsets within three months of operation and 90.2 per cent within six months. I n only 9.8 per cent was the interval between

SIEGEL ET AL. :

operation and months.

TONSILLECTOMY

onset more than

six

There were twelve deaths among the post-tonsillectomized cases of poliomyelitis, all within six months after operation. The distribution of deaths by monthly interval between operation and onset is shown in Table VI. TABLE VI

BET WEEI'~ INTERVAL

FATALITY

OPEF~ATION AND ONSET

AND P O L I O M Y E L I T I S .

CASES

DEATttS

(% )

0-1 I-2 2-3 3-6 6-12 Total

30 32 34 79 19 194

4 4 0 4 0 12

13.3 ].2.5 0.0 5.1 0.0 6.0

551

The fatality of bulbar cases occurring within the first two months after operation was 30.8 per cent as against 18.2 per cent after the Second month. The difference was not considered statistically significant for the small numbers in the groups.. TABLE VII ]NTERVAL BET%VEEN OpErATION ANDONSET

0-2 2-12

CASE FATALITY

BULBA~ CASES

CASE

(MONTHS)

II.

26 22

DEATHS

8 4:

(%) 30.8 18.2

It was apparent that a study of tim type of paralysis in 194 cases by various categories for the purpose of finding significant relationships would entail the analysis of small samples The case fatality was 12.9 per cent that could be misleading. In order to in cases occurring within the first two reduce the chances of error, the months after operation and 3.1 per method of study based on the findings cent in cases occurring more than two in all cases of poliomyelitis was supmonths after. The difference was plemented by another method designed statistically significant. to reduce the element of bias and to The case fatality expected among facilitate comparisons between samples the 194 cases on the basis of deaths if the data on all cases were unknown. by age group and by y e a r of onset for The method employed was based on all of the 6,524 reported cases was 4.4 the random selection of cases without per cent. I t was significantly lower a history of tonsillectomy which than the rate observed for cases oc- matched the post-tonsillectomized cases curring within two months after opera- with respect to such known charactertion, and was indicative of a more istics as age, sex, color, date of onset, severe form of poliomyelitis in cases and borough of residence. The ranoccurring shortly after operation than domly selected cases were called the in other groups of cases of comparable "control g r o u p " or " m a t c h e d age and year of occurrence. sample. ' ' The deaths in the post-tonsillectoThe following procedure was folmized cases occurred from one to eight lowed in the selection of the matched days after the onset of symptoms of s a m p 1 e. The post-tonsillectomized poliomyelitis. All of those who died cases reported each year were removed had bu]bar paralysis. The case fatalfrom the files and charted by borough ity of bulbar poliomyelitis following o f residence and date of onset and tonsillectomy is given in Table V I I by assigned a case number in consecutive interval between operation and onset. order starting with the earliest re-

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ported case. All other eases reported in a given year, filed alphabetically by borough of residence, were reviewed in consecutive order. The first to match a postoperative case by age, sex, color, and date of onset was selected for the matched s a m p l e and given the case number of its counterpart in the postoperative group. Some leeway had to be allowed for cases that could not be matched exactly. In these instances, those chosen were closest to the date of onset and of the same sex, color, and age. I n a few exceptions, either the sex differed, or the age differed by plus or minus one year within the same age group. B y this process it was possible to select at random 194 reported cases of polio-

summarized in Table V I I I giving the percentage of bulbar, spinal, and nonparalytic cases in each of the groups. The percentage of cases with bulbar paralysis varied from 56.7 per cent at 0 to 1 month after operation to 0 per cent at 6 to 12 months after operation. The percentage of cases with bulbar paralysis within one month of operation was two or more times greater than in any other group shown in the table, and ahnost twenty times greater than its comparable control group in the m a t c h e d sample. A f t e r the first month, the" differences in the percentage of bulbar paralysis between tonsilleetomized and control groups were either nil or not statistically significant (Table V I I I ) .

TABLE ~r PERCENTAGE :DISTRIBUTION OF CLINICAL TYPES OF POLIOMYELITIS BY ]V[ONTHLY INTERVAL BETWEEN OPERATION AND ONSET IN TONSILLEOTOMIZED GROUPS~ AND IN

]~AND01Y[LY SELECTED CONTI%0L GI%OUPS ]/VIT}IOUT IIISTO•Y OF TONSILLECTOMY MONT}ILY INTERVAL BETWEEN OPERATION AND ONSET

01

Cases Bulbar Spinal NonparMytie

30 56.7 30.0 13.3

Cases Bulbar Spinal Nonparalytie

30 3.3 70.0 ~26.7

I

12 I 23 Tonsillectomized

32 28.1 43.8 28.1

34 20.6 26.5 52.9

I 34 Groups

46 J7.4 54.3 28.3

Randomly Selected Control Samples

32 25.0 40.6 34.4

myelitis without a history of tonsillectomy each of which was similar to a tonsilleetomized ease with respect to the characteristics noted above, and then to set the cases of one group against the matched cases of the other in studying the effects of tonsillectomy on poliomyelitis occurring after the operation. The tonsillectomized cases and the m a t c h e d , sample were grouped by monthly intervM b.etween operation and onset. The results obtained are

34 20.6 58.8 20.6

4~ 17.4 52.2 30.4

I

46

I

612

33 2].2 48.5 30.3

19 0 47.4 52.6

33 6.1 51.5 4'2.4

19 5.2 63.2 31.6

These results are shown graphically in Chart 1 which also gives the percentage of cases with bulbar paralysis expected on the basis of its frequeney by age group and year of onset for the 6,524 eases reported from 1944 to 1949. The expected percentage of bulbar cases was 14.3 per cent. This was significantly different from the observed value of 56.7 per cent at 0 to 1 month. I t was also consistently lower than the percentages observed up to 6 months after operation. Com-

SIEGEL ET At. :

T O N S I L L E C T O M Y AND P O L I O M Y E L I T I S ,

pared with the matched samples, the expected value was lower in three groups and higher in three groups in keeping with the degree of sampling variation anticipated in randomly selected groups. It was apparent from the studies that bulbar paralysis was more common than expected in cases of poliomyelitis occurring within one month

II.

553

the description of the post-tonsillectomy cases which follows. The data from 6 to 12 months were omitted because there were no indications of any predisposition to bulbar paralysis during this period. The clinical types of poliomyelitis observed among the post-tonsilleetomized cases in epidemic and nonepidemic periods are ~ v e n in Table IX.

I00

90 SO 7O

]

TONSiLLECTOMiZEOCASES

]

NON-TONS|LLECTOMIZF-DGASES (RANDOMSAMPLE)

60 l

J!i 0-1

I-2 MONTHLY

Chart 1.--Bulbar

2-3

3-4

4-6

6-i2

INTERVALSBETWEEN OPERATION AND ONSET

poliomyelitis by monthly intervals between operation and City, 1944 t o 1949.

after operation. A f t e r the first month of operation up to the sixth month, the results were inconclusive. At 6 to 12 months after operation, there were no indications of a predisposition to bulbar paralysis in the small group studied. Since the results within one month of operation were statistically significant, they were treated separately in

onset, Ne-0v Y o r k

Although the numbers were small, the predisposition to bulbar paralysis within a month after operation seemed to be more clearly evident during the nonepidemic years of 1945 to 1948 than in the epidemic years of 1944 and 1949. Eleven of the seventeen bulbar cases observed in the first month occurred in nonepidemic years. During these years, the percentage of

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TABLE IX

O-I MONTI{

YEAE 1944 1945-48 1949 Total

-TOTAL .10 14 6 30

BETWEEN AND ONSET

OPERATION

i - - i - I BULBAE I sPINAL 4 4 11 2 2 3 ]7 9

1-6 ~ O N T H S BETWEEN OPERATION AND ONSET NONPARA ~ BULBAIr SPINAL LYTIC I TO,PAL 42 8 23 11 40 10 ]6 14 63 13 34 16 145 31 73 41

I

1 LYTIC 2 1 1 4

TABLE X

MONTH OF ONSET J~nuary February March April May June July Al~gust September October Nbvember December Total

0-1 /V~ONTI~ BETWEEN OPERATION AND ONSET NONPARATOTAL BUDBAR SPINAE LYTIO 1 O 1 O 0 0 0 1 1 0 0 1 1 0 0 5 2 2 1 7 4 2 1 5 2 '2 1 5 5 0 O 3 1 2 0 2 1 0 1 30 17 9 4

patients with bulbar paralysis within the first month of operation was about twice that observed in the epidemic years. At 1 to 6 months a f t e r operation, the frequency of bulbar paralysis in epidemic and nonepidemie years was 20 per cent and 25 p e r cent, respectively. The high frequency of bulbar paralysis during nonepidemie years indicates t h a t the hazards o f tonsillectomy were not limited to epidemic periods. , :The relationship of post-tonsilleetomized eases to month of onset is shown in Table X. The distribution of eases f r o m I to 6 months a f t e r operation paralleled the seasonal incidence of the disease with about 80 per cent in the s u m m e r and 20 per cent in the fall.~~ However, eases oe*The t e r m s w i n t e r , s p r i n g , s u m m e r , a n d f a l l r e f e r to t h e first, s e c o n d , t h i r d , a n d f o u r t h quarters of the year.

.1.-6 MONTHS BETVVEEN OPERATION AND ONSET NONPAI~A TOTAL BULBAR SPINAL LYTIE O 0 0 0 O 1 1 0 0 24 7 12 5 63 15 30 18 40 5 24 11 10 3 3 4 3 0 1 2 4 0 3 1 145 31 73 41

curring within a month of operation showed less dependence on seasonal incidence and a more even distribntion so t h a t 57 per cent occurred in the summer, 33 per cent in the fall, and 10 per cent in the winter and spring'. W h e r e eases of poliomyelitis occurred within the first month a f t e r operation, the percentage of patients with bulbar paralysis was almost always high regardless of month of onset. The percentages were somewhat higher in the spring and fall than in the summer. However, no bulbar cases were observed d u r i n g the winter. I t therefore seems t h a t timing t h e operation in the spring and fall was in itself no safeguard against the development of bulbar paralysis; and that the winter is the least dangerous for elective operations f r o m the standpoint of poliomyelitis.

SIEGEL ET AL. :

TONSILLECTOMY AND POLIOMYELITIS.

555

1I.

TABLE X I

AGE

0-1 ~ O N T H BETWEEN OPERATION AND ONSET NONPA~ATOTAL BULBAR SPINAL LYTIC

0- ~ 5- 9 1044 15-19 20 a n d o v e r Total

]1 14 4 0 1 30

9 6 2 0 0 17

2 6 0 0 1 9

1-6 ~ONTHS BETWEEN OPERATION AND ONSET NONPARATOTAL BULBAR SPINAL LYTIC

0 2 2 0 0 4

Tm~LE

30

Total

TABLE

BETWEEN OPERATION AND ONSET NONPA~A~ BULBAR SPINAL LYTIC 11 6 2 6 2 q 3

TOTAL !9 11

17

9

13 17 0 0 1 31

38 31 3 1 0 73

17 21 2 1 0 41

L 6 3s

BETWEEN OPERATION AND ONSET

XII

0-I ~0NTH

SEX Male Female

68 69 5 2 1 145

TOTAL EULEAR SPINAL LYTIC______

4

81 64

16 15

32 41

33 8

145

31

73

41

XIII. CLINICAL TYPES OF POLIOI~IYELITIS FOLLOWING TONSILLECTOMY BY INTEI~VALS DAYS AND WEEKS BETWEEN OPERATION AND ONSET FOR CASES OCCURRING %VITHIN TIcIE INCUBATION ]PERIOD

OF

INTERVAL IN DAYS AND WEEKS BETWEEN OPERATION AND ONSET

I FIaS~WEEX ,T~-S i ~ 1 2 3

Totals Bulbar Spinal Nonparalytic

S~CO~,WZRX Tm~DW~EX ~O,~T~WEEX r~PTIIWSEK "AYSIEAS~S ,AYSICASES --,AYS i &SE~ ,A~SlCASES

S -B

8 9 10

4

--

5 6 7

-B B 4 3 1 0

~ B,B,B -_

15 16 17

B,B N B

11

B~S

18

B,S

25

S

3~

12 13 14

~,S

19 20 21

B

26 27 28

lg

33 34 35

B,B 10 8 2 0

*The letters designate the clinical form N ~-"Nonp&ralytic, __ z No ease.

The eases of butbar paralysis in various age groups is shown in Table X I . As expected, most of the bulbar eases were u n d e r 10 years of age because the n u m b e r of the operations and ,incidence were greatest" in this age group. The frequency of bulbar paralysis was high within a month a f t e r operation in all age groups in which more than one ease occurred, and somewhat higher u n d e r 5 years of age t h a n 5 years and over. Ex-

in e a c h

22 23 24

B,S,N 10 6 ~ 2 case,

viz.,

B

B,S __ _-

N 5 1 2 2 -~ B u l b a r .

29 30 31

S

__ B N S

-__ --

=

3 1 1 1 Spinal.

eluding the age groups 15 years and over, for which there were insufficient data, the predisposition of post-tonsilleetomized cases to bulbar paraiysis did not seem to be dependent on age. .... The numbers were too small for analysis b y sex and age combined, so t h a t the distribution of type of paralYSiS by sex alone is given in Table X I I . Males predominated in a ratio of 57:43 wSich was comparable to tile sex ratio observed for all eases. The

556

TttE JOURNAL OF PEDIATRICS

differences in the percentage of bulbar cases among males and females were not significant. The relationship of the clinical t y p e s of poliomyelitis occurring shortly after operation to the incubation period of the disease is shown in TaMe X I I I by intervals of days and weeks between operation and onset. All cases occurring within thirty-five days after operation, the extreme upper limit of the incubation period, are presented in Table X I I I . The cases were widely scattered during the presumed incubation period of the disease, most of them occurring in the second and third weeks after operation. The frequency of bulbar paralysis decreased progressively from 78 per cent in the first two weeks after operation, to 60 per cent in the third week, and to 25 per cent after that. The period with the highest percentage of bulbar cases was less than twentyone days between operation and onset, which corresponded to the usual incubation period. DISCUSSION

The data obtained in New York City in recent years confirm the results reported from other sources on the predisposition of recently tonsillectomized cases of poliomyelitis to bulbar paralysis. 2-23 T h e relationship b etween bulbar paralysis and tonsillectomy seems firmly established for cases occurring within one month of operation. It was most marked in the first three weeks or within the usual incubation period of poliomyelitis. The duration of the predisposition to bulbar poliomyelitis could not be precisely ascertained from the available data. There was some indication of

its persistence for as long as six months in certain cases, but the results on the frequency of bulbar paralysis after the first month were not statistically significant, nor demonstrable by all methods of analysis. The increased frequency of bulbar paralysis after operation was accompanied by an increase in ease fatality. The increase in case fatality was greater than expected for cases of poliomyelitis occurring within the first two months after tonsillectomy. It represents additional evidence that the danger period after tonsillectomy may last for more than one month in some cases.

The predisposition to bulbar paralysis observed within one month after operation was more evident in nonepidemic years than in epidemic years, and in the spring and fall, than in the summer. The influence of these two time factors could not be accurately measured, because the number of cases was too small for the extent of the differences observed. Both were related to periods when the incidence of poliomyelitis was not maximal and when the number of operations was presumably increased. Regardless of the explanation, the high frequency of bulbar paralysis when the incidence of poliomyelitis was not inordinately high represented a hazard that might be considered in scheduling elective operations. In this connection, it is significant that no cases of bulbar paralysis following tonsillectomy were encountered during the winter months. The absence of bnlbar cases in the winter was associated with the infrequency of all forms of poliomyelitis during this

S I E G E L E T AL. :

TONSILLECTOMY

period, and added weight to the impression gained f r o m studies on incidence t h a t the winter months are the safest f o r tonsillectomy. ~ W i t h modern chemotherapy, it m i g h t be feasible either to reduce the n u m b e r of tonsillectomies or to schedule more operations for the winter and fewer for other seasons. The shift in timing would not only conform to the current trend of postponing elective operations during the poliomyelitis season, but would also take into consideration the possibility of an oncoming epidemic. One of the difficulties in the s t u d y was the necessity of working with small samples because of the low incidence of poliomyelitis. I n order to check the results and reduce the elem e n t of bias, comparative tests were m a d e against r a n d o m l y selected cases without a history of tonsillectomy and similar to the tonsilleetomized in such known characteristics as age, sex, borough of residence, a n d date of onset. The method was applicable to the s t u d y of such factors as t y p e of p a r a l y s i s and course, and is usefuI when d a t a on all r e p o r t e d cases are not available. The results obtained in the present report on b u l b a r paralysis supplemented those in the previous report on incidence of poliomyelitis. While the available data on incidence revealed no increase in the n u m b e r of p a t i e n t s observed at 0 to 4 y e a r s of age, a well-marked predisposition to bulbar paralysis was noted in this age group within one m o n t h a f t e r operation. A t 5 to 9 years of age, the combined evidence pointed not only to a g r e a t e r percentage o3 bulbar eases but also to a g r e a t e r n u m b e r of eases.

AND POLIOMYELITIS.

IL

557

SUMMARY

1. A s t u d y was made of the frequency of bulbar paralysis in 194 cases of poliomyelitis occurring within one y e a r of tonsillectomy. Those in the s t u d y were selected f r o m a total of 6,524 cases of poliomyelitis reported in New York City f r o m 1944 through 1949. 2. Two methods of analysis were employed, one based on the corrected expectancy o3 bulbar paralysis from its distribution among all cases reported during the six-year period under consideration, the other based on the results in a r a n d o m l y selected group of cases without a history of tonsillectomy and comparable to those tonsillectomized with respect to age, sex, borough of residence, a n d date of onset. 3. B y both methods employed in the study, the percentage ~f b u l b a r p a r a l y sis was significantly higher t h a n expected a m o n g post-tonsillectomized eases within one month of operation. The results were inclusive f r o m one to six months a f t e r operation. No increase in the percentage of bulbar paralysis could be demonstrated in a small group of cases f r o m six to twelve months after operation. The critical period when bulbar parMysis was most c o m m o n was the first three weeks following operation. 4. A n increase in case f a t a l i t y was noted among cases occurring within two months a f t e r o p e r a t i o n . CONCLUSION

The data presented s u p p o r t the view that cases of poliomyelitis occurring shortly a f t e r tonsillectomy are predisposed to bulbar paralysis.

558

THE JOURNAL OF PEDIATRICS

Under the conditions prevailing in New York City from 1944 to 1949 with respect to poliomyelitis, the most desirable months for elective operations seem to be the winter months which are farthest removed from the poliomyelitis season. We are grateful to Dr. John W. Fertlg, Professor of Biostatistics at Columbia University, for reviewing the manuscript and the statistical methods used, and for his many helpful suggestions.

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