557

THE TENACITY OF THE FRONTAL SINUS MUCOSA PAUL J. DONALD, MD SACRAMENTO. CALIFORNIA

A number of persons in other surgical disciplines express a blatant disregard for the potential dangers of frontal sinus mucosal entrapment. Although bone removal is universally recommended by the otolaryngologic proponents of ablative procedures in the frontal sinus, no comprehensive explanation has been proffered to justify this dictum. To this end, 27 cats had simple excision of the frontal sinus mucosa to see if it is necessary to bur away the inner table of bone to completely eliminate all vestiges of mucosa. Mucosal regrowth was seen in 72%, and suppurative infection, in 17% of the sinuses. Burring away of the frontal sinus inner table must then be considered as an essential part of any ablative procedure of the frontal sinus.

MOST otolaryngologists possess a healthy respect for the dangers inherent in frontal sinus injury. A fairly uniform approach to trauma to this sinus is employed.t-s operating under the dictum of "being conservative by being radical." This is necessary because of the serious sequelae resulting from mucosal disruption, especially in the regions of the frontonasal duct and the posterior sinus wall. However, many of these disastrous consequences, especially mucocele and mucopyocele formation, may take months and often years to develop. This has lulled many in the plastic and neurologic surgical disciplines into a sense of

Submitted for publication Nov 1, 1978. From the Department of Otorhinolaryngology, University of California, Davis, Medical Center, Sacramento. Presented at the 1978 Annual Meeting of the American Academy of Otolaryngology, Las vegas, Sept 10-

13. Reprint requests to Department of Otorhinolaryngology, UCD Medical Center, 4301 X St, Room 208, Sacramento, CA 95817.

false security. Since they generally follow up most of their patients for a short postoperative period, they unfortunately miss these slowly developing complications.

If a neurosurgeon inadvertently enters the frontal sinus during craniotomy, or a fracture has occurred during trauma, the standard advice is either to leave the sinus alone or to simply curette the mucosa and obliterate the frontonasal ducts with a muscle or fascial plug. The specialty has been frequently chided by the general plastic surgeons 7•8 for its aggressive approach to these problems. A typical example of the blatant disregard of frontal sinus injury is seen in Fig 1. The authors of the articles in which this photograph first appeared provided a detailed description of this patient's facial fractures but made no mention of the presence of the air fluid level in the frontal sinus that probably resulted from injury to the frontonasal ducts. At the University of California, Davis, Medical Center this year, on two occasions, the neurosurgical service transected the superior pole of the frontal sinus during frontal craniotomy. Excision of the mucosa was attempted by simple blunt dissection from the sinus cavity, and muscle was used as the obliterating agent. A mucocele ensued in one patient at six months, and chronic sinusitis with osteitis of the anterior sinus wall occurred in the second patient at three months (Fig 2 and 3). Bone removal from the sinus cavity is universally recommended by the otolaryngologic proponents of obliterative procedures in the frontal sinus. Some scant scientific evidence 10•11 but no comprehensive explanation has been proffered

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558

PAUL ]. DONALD

Fig 1.-Poslerior-anterior radiograph before (left) and after (right) surgery. Note fluid level in right frontal sinus (from Shaw and Parsons").

Fi~ 3.-0steoplastic flap turned, revealing chronically

11'4 2.-Pati('nt who had under gone tramlrontal r r aniotornv three months pr eviouvlv and now ha' Ipver, lrontal erythema, and hpad.H he. Coronal flap h,,, bppll turne-d. and frontal vinuv outlined with mlpolonH' c utv. Noll' Sila,'i( button from bur hole in f ronta l sinus Chronic ally inflamed 'IOU' mue ma h,,, grown uut 01 bur hole and OV('l «xternal surface of frontal bone.

to justify this dictum. In order to more clearly delineate the reasons for this stance, the following experiment was designed.

METHOD AND MATERIALS Surgical obliteration of the frontal sinus was attempted in 27 cats. They were anesthetized with intravenous sodium

intlarned frontal vinus mucosa.

pentobarbital. Their heads were shaved, scrubbed, and draped under sterile conditions. A bilateral brow or "butterfly" incision was made. The galea was dissected from the frontal area, and the periosteum was incised in the approximate area of the outer margin of the frontal sinus. Multiple bur holes were made through the perimeter of the sinus. These were connected with an osteotome, the intersinus septum was severed, and the osteoplastic flap was elevated.

Oto/aryngol Head Neck Surg 87:557-566 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV NEBRASKA LIBRARIES on May 25, 2016

FRONTAL SINUS MUCO SA The frontal sinus mucosa was meticu lously dissect ed from the sinus cavity with a sharp elevato r under microsc opic control. Followi ng this, the cavity was curetted thoroug hly with a stapes curette . The mucosa of each fronton asal duct was inverte d on itself. Obliter ation of the cavity was attemp ted in three ways (Table 1). Fat oblitera tion was attemp ted in nine animals , using fat taken from the subcutaneo us layer of the abdomi nal wall. A short-c hain bovine collage n extract similar to Gelfoam was used in 16. No agent was employ ed in two cats, anticipa ting oblitera tion by osteon eogene sls."

559

ization with 5% NaSO. require d two days. For one day, the specim ens were washed in tap water followe d by dehydr ation in absolut e ethanol . The imbedd ing in eelIodin require d nine weeks: two weeks in a 4% solutio n, 8% for three weeks, and 12% for four weeks. The tissue was harden ed with eel•. Serial histolog ic sections, 10~ in thickne ss, were taken in the horizon tal plane throug hout the entire frontal sinus. Each tenth section was stained alterna tely with hemato xylineosin and Mallory 's trichro me stain. The section s were examin ed for the degree of oblitera tion, the presenc e of infectio n,

TABLE 1 TIME OF ANIMAL DEATH FOR THE VARIOU S METHOD S Of FRONTAL SINUS OBLITERATION OBLITERATING AGENT TIME ANIMAL WAS KILLED. "'10

2 7109 12 Total

FAT

COLLAGEN

NONE USED

4

TOTAL

4

1 15· 16

1 4

9

2 21 27

2 2

The osteopl astic flap was returne d, the periost eum was sutured , and the skin was closed with interru pted catgut sutures . Each animal was given 1.2 million units of penicill in.

the amoun t of epitheli al regrow th, and the presenc e of a mucoce le or mucop yocele.

The cats were killed at interval s of 2, 7, 9, and 12 months using an overdo se of sodium pentob arbital. The frontal sinuses were excised in the followi ng manner . The frontal area of the cranium , from the corona l suture anterio rly to include the orbital roofs, was excised immedi ately with a Stryker saw, and the specim ens were immers ed in 10% formali n for two weeks. Decalci fication require d three to four weeks' immers ion in a solutio n of 1% nitric acid and 10% formali n. Neutral -

Table 2 is a summa ry of the results seen in the 27 animals in which frontal sinus ablation was attemp ted. The rapidity of epitheli al regrow th was remark able. One half of the animals termina ted at two months and both of the animals examined at seven and nine months after oblitera tion were found to have epithel ial regrow th. This regrow th was present in 32 out of 42 (76%) cat sinuses in those that were killed after 12 months (Fig 4 and 5). The fewest sinuses with epitheli al re-

RESULTS

Oto/ary ngol Head Neck Surg 87:557-566 (Sept-Oct) 1979 Downloaded from oto.sagepub.com at UNIV NEBRASKA LIBRARIES on May 25, 2016

0

TABLE

siii ..,

III

2

eQ

RESULTS OF OBLITERATION OF CAT FRONTAl SINUSES

-e

::J

I)Q

0

J: I'\)

ll>

CAT NO.

OBLITERATING AGENT

Downloaded from oto.sagepub.com at UNIV NEBRASKA LIBRARIES on May 25, 2016

0-

509

Fat

2: I'\)

510

Fat

519

Fat

520 390 425 448

Collagen

LEFT

PERCENT OF OBLITERATION RIGHT

100 80

100

Fat

0 100

Fat

0

0 100 100

80

EPITHELlALIZA TION

VI

..,c

None

None Slight acute inflammation

Both sinuses

Pus. both sides

2 2

None

None

2

Both sinuses

Mucopyocele with large abscess

00

7

Both sinuses

None

None

None

:';I I.n I.n

'I I

I.n

0'1 0'1

None

75 100

2

9 12

Abscess

0

0 0

Both sinuses

Collagen

Both sinuses

Large abscess, left

12

0

213

Collagen

0

0

Both sinuses

Pus

12

....

689 679

Collagen

0

0

Both sinuses

Pus

12

Collagen

0

0

Both sinuses

Pus

12

676 495

Collagen

0

0

Both sinuses

Scant pus

12

Collagen

0

Both sinuses

Abscess

426

Collagen

0 15

Both sinuses

Pus

12 12

489

Collagen

0

0 0

Both sinuses

Abscess. left and right

12

641

Collagen

100

85

None

None

12

400

Collagen

0

50

Both sinuses

Chronic inflammation

252

Collagen

40

70

Both sinuses

Chronic inflammation

12 12

680

Collagen

80

50

Both sinuses

Abscess. right

12

I'\)

~I

!:l .....

1.0 'I 1.0

""C

>-

C

r"

~

436 449

..... VI

None

0 100 15

DURATION OF IMPLANT. MO

One sinus

r"l ,.,..

I)Q

INFECTION

12

0

0 Z

>-

r"

0

FRONTAL SINUS MUCOSA

0 :E z . 0>-z >-0( 0(-,

....N N....

....N

N

a:Q.

N

.... N....

N

::):::! 0-

561

growth were those in which the obliteration was attempted with fat. Of the nine fat grafts, five sinuses showed no evidence of lining epithelium. On the other hand, only one of 16 collagen grafts had sinuses devoid of epithelium.

LL

0

c 0

(ij

-0( Za: Ww u>a:w-'

Q.~

>w

0 ,...

0

0

->>-z o(w

C

C

C

Q)

Q)

Q)

Cl

a: " ~o(

Cl al

(5

(5

::::l ~

LL

0

-'

~

ez

::;

~

o

lD

0

0 z >0(

o

,... ,... ll"l

0>

U)

seven instances, collagen in one, and no obliterating agent was used in two others.

U)

M

N