- Email: [email protected]
Reaction of oral tissues to suture materials. IV
Reaction of oral tissues to suture materials. IV Gillmrt E:. Lilly, Colo~cl, DC, i78A,” James L. Cutche,r, Lieuteaad Colonel, DC, USA,** John C. Joxes, Major, DC, UXA,+** and James Ii. Armstrong, San Pra~mGsco, Calif. LETTERMAN
ARMY
INSTITUTE
OF
RESEARCH,
SBN
FRANCISCO,
B.S,,+xrA* CALIF.
In a histologic study of the oral tissue response to seven different suture materials, the monofilament suture materials and the multifilament resorbable suture material, polyglycolic acid, were found to be associated with milder tissue responses than the nonresorbable multifilament suture materials studied, even though some of the latter materials were impregnated with antibiotics. Antibiotic impregnation did, however, appear to improve the relative tissue response as compared to untreated nonresorbable multifilament sutures.
I
n previous studies on animals, the reaction of oral tissues to suture materials has been reported to be milder in association with monofilament sutures as compared to multifilament suture materials. l-3 The physical nature of the suture (that is, whether monofilament or multifilament) appeared to be the most important factor in determining tissue response. These findings suggested dhat the presence of bacteria within the interstices of the multifilament sutures was a major factor affecting tissue response. Although these studies have indicated the superiority of the selected monofilament sutures to the multifilament sutures studied, when used in the oral cavity, there is a continuing need for research in this area, since the monofilament sutures are difficult to handle, are more irritating to the patient, and frequently come untied. Recently, Wallace and associates,4 have reported favorable tissue responses with multifilament braided polyglycolic acid sutures in clinical trials on human beings. The present study was undertaken to evaluate the braided polyglycolic suture material and to investigate the feasibility of impregnating multifilament sutures with antibacterial agents in order to prevent bacterial infiltration. *Chief, Maxillofacial Sciences Division. **Assistant Chief, Maxillofacial Sciences ***Chief, Oral Surgery Branch, Maxillofacial ““““Maxillofacial Sciences Division.
152
Division. Sciences
Division.
Volume Number
IZeuction
33 1
of oral tissues
to suture
m.aterials
153
Table I T&sue SzLture
material
Nylon (monofilament) Polyglycolic acid (braided) Chromic (medium) Silk (braided) with tetracycline Silk (braided) with Bicillin Silk (braided) with procaine penicillin Silk (braided)
Mild
2;
yfm;
Severe
Tot& number of specimens
if t2:F;
30 19
response
) Moderate 3 (27%)
)
El i&F{ 4 (3&) 2 (W& 13 (37%) i: 15 (432) 7 (20%) 12 (37%) 12 (37%) : tit?; 2i 7 (29%) 11 (46%) 67 11 (16%) 20 (30%) 36 (54& The figures under each type of tissue response indicate the number of specimens judged representative for each response to each material. Percentages are based on the total number of tissue specimens available for each suture material. Suture materials are listed in the order of their comparative mean tissue response, based on arbitrary values of 1, 2, and 3 assigned to “mild,” “moderate,” and ‘(severe” responses.
MATERIALS AND METHODS Seven different sutures were selected for this study. All sutures were of the 4-O size and were prepackaged in individual sterile packs. Antibiotic-impregnated sutures were prepared by placing black braided silk sutures in concentrated solutions of either Bicillin, tetracycline, or procaine penicillin for 24 hours. Subsequent to soaking in antibiotic solutions, sutures were removed from the solutions and immediately placed in the animals. Twenty-one adult mongrel dogs served as the experimental subjects. Each animal was given a general anesthetic, and interrupted sutures were placed through the intact buccal mucosa and lateral border of the tongue with a half-circle cutting needle. A separat.e sterile needle was used for each suture. Eight sutures (one of each type, plus an additional black silk suture) were placed in the buccal mucosa, and the same number were placed in the tongue of each animal. The anatomic location of the different suture materials was varied from one animal to another. Fourteen of the animals were killed in groups of two 1, 2, 3, 4, 6, 8, and 10 days postoperatively. At death, the tissues were recovered by block section and fixed in 10 per cent neutral buffered formalin. Block sections were grossed at a point perpendicular to the suture path at the greatest suture depth. After grossing, the sutures were carefully removed, and the tissues were processed for histologic study. Multiple sections were cut at 5 microns and stained with hematoxylin and eosin. All sections were examined microscopically, without the examiner knowing the type of suture material used. The tissue reaction was arbitrarily classified as mild, moderate, or severe, depending upon its intensity, nature, and extent. Four animals were killed 4 days and three animals were killed 6 days after placement of sutures. Their tissues were processed as previously described, except that the sutures were not removed when the tissues were grossed, and selected sections were stained with Brown and Brenn tissue Gram stain. RESULTS The results of the microscopic examination are summarized in Table I. The reactions associated with the sutures placed in the buccal mueosa and
Fig. 1. Section of polygly~~olic: acid suture filaments are bqinning to untlcrgo degmd:ttion, ation. (Brown nntl Xrelln stain. Magnifkntion,
rct:hed and x970.)
in dog’s mwosn for (i (1:~~s. The suture therc~ is no evidence of hcterial perme-
in the tongue were comparable and, thcrcfore, will not be described separately. The tissue responses on the first three postoperative dcat,h dates (1, 2, and 3 days) were less consistent. for specific suture materials than those observed in later specimens. Reactions associated with one-day specimens consisted of hemorrhage, edema, and a mild inflammatory infiltrate which was primarily neutrophilic. There was little variability among the different types of suture material, and most, rtact,ions were classified as moderate. Specimens examined 2 and 3 days after placement of sutures exhibited divcrgent reactions which were more consistent for each type of suture material. Mild reactions consist&l of a localized inflammatory infiltrate of neutrophils, lymphocytes, and histiocytes. Early evidence of fibroblastic activity was observed. Severe reactions showed a broader zone of inflammatory reaction, with a dense infiltrate of neutrophils and little evidence of fibroblastic proliferation. Four to 6 days after placement of sutures, mild reactions were characterized by increased fibroblastic proliferation and a circumscribed inflammatory infiltrate of lymphocytes, neutrophils, and plasma cells. An occasional foreignbody giant cell was observed. These did not appear to be specific for any type of suture material. In the severe reactions, there was no evidence of significant fibroblastic proliferation or foreign-body giant cells. The inflammatory infiltrate was dense, not circumscribed, and predominantly neutrophilic. Eight to 10 days after placement of sutures, mild reactions exhibited progressive fibrosis and contained a mild infiltrate of plasma cells and lymphocytes. Foreign-body giant cells were observed in some cases. These were not specific for any type of suture materials. Severe reactions contained a diffuse neutrophilic inflammatory infiltrate with microabscesses. Responses that were judged to be moderate were observed at all postoperative dates. These were intermediate between the mild and the severe reactions. None of the sections interpreted as showing moderate reactions contained microabscesses.
Reaction
Pig. 2. Sections of braided cosa for 4 days. Note the mild Magnification, x430.) Fig. 3. Section of specimen tion. (Brown and Brenn stain.
of
oral tissues
silk suture impregnated localized inflammatory illustrated Magnification,
to suture
materials
155
with tetracycline retained in dog’s muinfiltrate. (Hematoxylin and eosin stain.
in Fig. 2. There x970.)
is no evidence
of bacterial
permen-
Brown and Brenn staining of sections prepared from specimens with sutures in place revealed numerous small particles within the interstices of the untreated silk sutures. On the basis of their morphology and staining characteristics, these particles were interpreted to be bacteria. The multifilament polyglycolic acid sutures did not contain bacteria within the interstices (Fig. 1). The multifilament silk sutures treated with antibiotics in some cases contained bacteria and in other instances did not contain bacteria between the filaments. Most 4-day specimens were free of bacteria, and approximately one half of the 6-day specimens contained bacteria in the treated sutures. The presence or absence of bacteria in association with the antibiotic-treated suture materials appeared to be directly related to the tissue response (Figs. 2 to 5). None of the antibiotic preparations
156
Lilly
et al.
Pig. penicillin acterized nification, Fig. between
4. Section containing braided silk and retained in the dog’s mucosa by a dense diffuse inflammatory x35.) 5. Section of specimen illustrated in the filaments of the suture. (Brown
tested
appeared
particles less
to
were
frequent
be
observed
markedly in
in number
did
Fig.
4. Note the numerous small bacterial particles and Brenn stain. Magnification, x970.)
superior
association
and
suture that had been iml>regnated with procaine for 6 days. Note the severe tissue response charinfiltrate. (Hematoxylin and cosin stain. Mag-
not
to
with
the
the
permeate
others.
Although
monofilament
the
bacterial
sutures,
they
were
suture.
DISCUSSION
To
date,
according
a total to
tions,
with
study,
the
the the
of
eighteen
laboratory exception
monofilament
different method
of suture
the
suture
described polyglycolic
materials
materials in acid
have
this
suture
consistently
have
been
In
study.le3 material been
evaluated
these used
associated
evaluain
this with
Volume Number
33 1
Reaction
of of-al tissues
to suture
materials
157
milder tissue rcsponsc than the multifilament materials. The relative acceptability of the multifilament polyglycolic acid suture further substantiates the findings of Wallace and colleagues4 as to the relatively mild reaction associated with this material. The mild tissue reactions observed and the apparent absence of bacterial particles within the interstices of the polyglycolic acid sutures suggest that this resorbable suture inhibits bacterial penetration and that this feature accounts for its milder tissue response. The variability of bacterial penetration observed in those sutures treated with antibiotics suggests that a more sophisticated method of impregnation than that employed in this study may be of value in further reducing the tissue response associated with the nonresorbable multifilament suture materials used in the oral cavity. Such treatment with antibiotics, however, does present additional potential problems relative to induction of antibiotic sensitivity in patients. SUMMARY The oral tissue response to seven different suture materials has been evaluated histologically in dogs. The monofilament suture materials and the multifilament resorbable suture material, polyglycolic acid, were associated with milder tissue responses than the nonresorbable multifilament suture materials studied, even though some of the latter materials were impregnated with antibiotics. Antibiotic impregnation did, however, appear to improve the relative tissue response ;1s compared to untreated nonresorbable multifilament sutures. These findings suggest that the polyglycolic acid suture inhibits bacterial penetration and that antibiotic impregnat,ion of nonresorbable multifilament suture materials may reduce the oral tissue response associated with untreated sutures. Principles of laboratory animal care as enunciated in the “Guide for Laboratory Facilities and Care” prepared by the Institute of Laboratory Animal Resources, Academy of Sciences, National Research Council, were observed in this study.
Animal National
REFERENCES
1. Lilly, G. E., Salem, J. E., Armstrong, J. H., and Cutcher, J. L.: Reaction of Oral Tissues to Suture Materials. Part III, ORAL SURG. 28: 432-438, 1969. 2. Lilly, G. E.: Reaction of Oral Tissues to Suture Materials, ORAL SURG. 26: 128-133, 1968. J. L.: Reaction of Oral 3. Lilly, G. E., Armstrong, J. H., Salem, John E., and Cutcher, Tissues to Suture Materials. Part II, ORAL SURG. 26: 592-599, 1968. 4. Wallace, W. R., Maxwell, G. R., and Cavalaris, C. J.: Comparison of Polyglycolie Acid Suture to Black Silk, Chromic, and Plain Catgut in Human Oral Tissues, J. Oral Surg. 28: 739-746, 1970. Reprint requests to : Colonel Gilbert E. Lilly Maxillofacial Sciences Division Letterman Army Institute of Research San Francisco, Calif. 94129
ARMY
INSTITUTE
OF
RESEARCH,
SBN
FRANCISCO,
B.S,,+xrA* CALIF.
In a histologic study of the oral tissue response to seven different suture materials, the monofilament suture materials and the multifilament resorbable suture material, polyglycolic acid, were found to be associated with milder tissue responses than the nonresorbable multifilament suture materials studied, even though some of the latter materials were impregnated with antibiotics. Antibiotic impregnation did, however, appear to improve the relative tissue response as compared to untreated nonresorbable multifilament sutures.
I
n previous studies on animals, the reaction of oral tissues to suture materials has been reported to be milder in association with monofilament sutures as compared to multifilament suture materials. l-3 The physical nature of the suture (that is, whether monofilament or multifilament) appeared to be the most important factor in determining tissue response. These findings suggested dhat the presence of bacteria within the interstices of the multifilament sutures was a major factor affecting tissue response. Although these studies have indicated the superiority of the selected monofilament sutures to the multifilament sutures studied, when used in the oral cavity, there is a continuing need for research in this area, since the monofilament sutures are difficult to handle, are more irritating to the patient, and frequently come untied. Recently, Wallace and associates,4 have reported favorable tissue responses with multifilament braided polyglycolic acid sutures in clinical trials on human beings. The present study was undertaken to evaluate the braided polyglycolic suture material and to investigate the feasibility of impregnating multifilament sutures with antibacterial agents in order to prevent bacterial infiltration. *Chief, Maxillofacial Sciences Division. **Assistant Chief, Maxillofacial Sciences ***Chief, Oral Surgery Branch, Maxillofacial ““““Maxillofacial Sciences Division.
152
Division. Sciences
Division.
Volume Number
IZeuction
33 1
of oral tissues
to suture
m.aterials
153
Table I T&sue SzLture
material
Nylon (monofilament) Polyglycolic acid (braided) Chromic (medium) Silk (braided) with tetracycline Silk (braided) with Bicillin Silk (braided) with procaine penicillin Silk (braided)
Mild
2;
yfm;
Severe
Tot& number of specimens
if t2:F;
30 19
response
) Moderate 3 (27%)
)
El i&F{ 4 (3&) 2 (W& 13 (37%) i: 15 (432) 7 (20%) 12 (37%) 12 (37%) : tit?; 2i 7 (29%) 11 (46%) 67 11 (16%) 20 (30%) 36 (54& The figures under each type of tissue response indicate the number of specimens judged representative for each response to each material. Percentages are based on the total number of tissue specimens available for each suture material. Suture materials are listed in the order of their comparative mean tissue response, based on arbitrary values of 1, 2, and 3 assigned to “mild,” “moderate,” and ‘(severe” responses.
MATERIALS AND METHODS Seven different sutures were selected for this study. All sutures were of the 4-O size and were prepackaged in individual sterile packs. Antibiotic-impregnated sutures were prepared by placing black braided silk sutures in concentrated solutions of either Bicillin, tetracycline, or procaine penicillin for 24 hours. Subsequent to soaking in antibiotic solutions, sutures were removed from the solutions and immediately placed in the animals. Twenty-one adult mongrel dogs served as the experimental subjects. Each animal was given a general anesthetic, and interrupted sutures were placed through the intact buccal mucosa and lateral border of the tongue with a half-circle cutting needle. A separat.e sterile needle was used for each suture. Eight sutures (one of each type, plus an additional black silk suture) were placed in the buccal mucosa, and the same number were placed in the tongue of each animal. The anatomic location of the different suture materials was varied from one animal to another. Fourteen of the animals were killed in groups of two 1, 2, 3, 4, 6, 8, and 10 days postoperatively. At death, the tissues were recovered by block section and fixed in 10 per cent neutral buffered formalin. Block sections were grossed at a point perpendicular to the suture path at the greatest suture depth. After grossing, the sutures were carefully removed, and the tissues were processed for histologic study. Multiple sections were cut at 5 microns and stained with hematoxylin and eosin. All sections were examined microscopically, without the examiner knowing the type of suture material used. The tissue reaction was arbitrarily classified as mild, moderate, or severe, depending upon its intensity, nature, and extent. Four animals were killed 4 days and three animals were killed 6 days after placement of sutures. Their tissues were processed as previously described, except that the sutures were not removed when the tissues were grossed, and selected sections were stained with Brown and Brenn tissue Gram stain. RESULTS The results of the microscopic examination are summarized in Table I. The reactions associated with the sutures placed in the buccal mueosa and
Fig. 1. Section of polygly~~olic: acid suture filaments are bqinning to untlcrgo degmd:ttion, ation. (Brown nntl Xrelln stain. Magnifkntion,
rct:hed and x970.)
in dog’s mwosn for (i (1:~~s. The suture therc~ is no evidence of hcterial perme-
in the tongue were comparable and, thcrcfore, will not be described separately. The tissue responses on the first three postoperative dcat,h dates (1, 2, and 3 days) were less consistent. for specific suture materials than those observed in later specimens. Reactions associated with one-day specimens consisted of hemorrhage, edema, and a mild inflammatory infiltrate which was primarily neutrophilic. There was little variability among the different types of suture material, and most, rtact,ions were classified as moderate. Specimens examined 2 and 3 days after placement of sutures exhibited divcrgent reactions which were more consistent for each type of suture material. Mild reactions consist&l of a localized inflammatory infiltrate of neutrophils, lymphocytes, and histiocytes. Early evidence of fibroblastic activity was observed. Severe reactions showed a broader zone of inflammatory reaction, with a dense infiltrate of neutrophils and little evidence of fibroblastic proliferation. Four to 6 days after placement of sutures, mild reactions were characterized by increased fibroblastic proliferation and a circumscribed inflammatory infiltrate of lymphocytes, neutrophils, and plasma cells. An occasional foreignbody giant cell was observed. These did not appear to be specific for any type of suture material. In the severe reactions, there was no evidence of significant fibroblastic proliferation or foreign-body giant cells. The inflammatory infiltrate was dense, not circumscribed, and predominantly neutrophilic. Eight to 10 days after placement of sutures, mild reactions exhibited progressive fibrosis and contained a mild infiltrate of plasma cells and lymphocytes. Foreign-body giant cells were observed in some cases. These were not specific for any type of suture materials. Severe reactions contained a diffuse neutrophilic inflammatory infiltrate with microabscesses. Responses that were judged to be moderate were observed at all postoperative dates. These were intermediate between the mild and the severe reactions. None of the sections interpreted as showing moderate reactions contained microabscesses.
Reaction
Pig. 2. Sections of braided cosa for 4 days. Note the mild Magnification, x430.) Fig. 3. Section of specimen tion. (Brown and Brenn stain.
of
oral tissues
silk suture impregnated localized inflammatory illustrated Magnification,
to suture
materials
155
with tetracycline retained in dog’s muinfiltrate. (Hematoxylin and eosin stain.
in Fig. 2. There x970.)
is no evidence
of bacterial
permen-
Brown and Brenn staining of sections prepared from specimens with sutures in place revealed numerous small particles within the interstices of the untreated silk sutures. On the basis of their morphology and staining characteristics, these particles were interpreted to be bacteria. The multifilament polyglycolic acid sutures did not contain bacteria within the interstices (Fig. 1). The multifilament silk sutures treated with antibiotics in some cases contained bacteria and in other instances did not contain bacteria between the filaments. Most 4-day specimens were free of bacteria, and approximately one half of the 6-day specimens contained bacteria in the treated sutures. The presence or absence of bacteria in association with the antibiotic-treated suture materials appeared to be directly related to the tissue response (Figs. 2 to 5). None of the antibiotic preparations
156
Lilly
et al.
Pig. penicillin acterized nification, Fig. between
4. Section containing braided silk and retained in the dog’s mucosa by a dense diffuse inflammatory x35.) 5. Section of specimen illustrated in the filaments of the suture. (Brown
tested
appeared
particles less
to
were
frequent
be
observed
markedly in
in number
did
Fig.
4. Note the numerous small bacterial particles and Brenn stain. Magnification, x970.)
superior
association
and
suture that had been iml>regnated with procaine for 6 days. Note the severe tissue response charinfiltrate. (Hematoxylin and cosin stain. Mag-
not
to
with
the
the
permeate
others.
Although
monofilament
the
bacterial
sutures,
they
were
suture.
DISCUSSION
To
date,
according
a total to
tions,
with
study,
the
the the
of
eighteen
laboratory exception
monofilament
different method
of suture
the
suture
described polyglycolic
materials
materials in acid
have
this
suture
consistently
have
been
In
study.le3 material been
evaluated
these used
associated
evaluain
this with
Volume Number
33 1
Reaction
of of-al tissues
to suture
materials
157
milder tissue rcsponsc than the multifilament materials. The relative acceptability of the multifilament polyglycolic acid suture further substantiates the findings of Wallace and colleagues4 as to the relatively mild reaction associated with this material. The mild tissue reactions observed and the apparent absence of bacterial particles within the interstices of the polyglycolic acid sutures suggest that this resorbable suture inhibits bacterial penetration and that this feature accounts for its milder tissue response. The variability of bacterial penetration observed in those sutures treated with antibiotics suggests that a more sophisticated method of impregnation than that employed in this study may be of value in further reducing the tissue response associated with the nonresorbable multifilament suture materials used in the oral cavity. Such treatment with antibiotics, however, does present additional potential problems relative to induction of antibiotic sensitivity in patients. SUMMARY The oral tissue response to seven different suture materials has been evaluated histologically in dogs. The monofilament suture materials and the multifilament resorbable suture material, polyglycolic acid, were associated with milder tissue responses than the nonresorbable multifilament suture materials studied, even though some of the latter materials were impregnated with antibiotics. Antibiotic impregnation did, however, appear to improve the relative tissue response ;1s compared to untreated nonresorbable multifilament sutures. These findings suggest that the polyglycolic acid suture inhibits bacterial penetration and that antibiotic impregnat,ion of nonresorbable multifilament suture materials may reduce the oral tissue response associated with untreated sutures. Principles of laboratory animal care as enunciated in the “Guide for Laboratory Facilities and Care” prepared by the Institute of Laboratory Animal Resources, Academy of Sciences, National Research Council, were observed in this study.
Animal National
REFERENCES
1. Lilly, G. E., Salem, J. E., Armstrong, J. H., and Cutcher, J. L.: Reaction of Oral Tissues to Suture Materials. Part III, ORAL SURG. 28: 432-438, 1969. 2. Lilly, G. E.: Reaction of Oral Tissues to Suture Materials, ORAL SURG. 26: 128-133, 1968. J. L.: Reaction of Oral 3. Lilly, G. E., Armstrong, J. H., Salem, John E., and Cutcher, Tissues to Suture Materials. Part II, ORAL SURG. 26: 592-599, 1968. 4. Wallace, W. R., Maxwell, G. R., and Cavalaris, C. J.: Comparison of Polyglycolie Acid Suture to Black Silk, Chromic, and Plain Catgut in Human Oral Tissues, J. Oral Surg. 28: 739-746, 1970. Reprint requests to : Colonel Gilbert E. Lilly Maxillofacial Sciences Division Letterman Army Institute of Research San Francisco, Calif. 94129