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A comparative study of wire osteosynthesis versus bone screws in the treatment of mandibular prognathism
A comparative study of wire osteosynthesis versus bone screws in the treatment of mandibular prognathism G. W. Paulus, M.D., D.D.S.,* and E. W. Steinhauser, M.D., D.D.S.,** Erlangen, West Germany In sagittal split osteotomies as well as in vertical osteotomies for reductron of the mandible, wire and bone screw osteosynthesis has been used in the Department of Oral and Maxillofacial Surgery of the University of Erlangen-Nuremberg within the last few years in a total of 221 cases of mandibular prognathism. In about one half of these cases a conventional wire osteosynthesis was performed, and in the other half a stable osteosynthesis with bone screws was used. One hundred twenty-one cases could be included in a follow-up study, and a true comparison could be made between the two methods. The results of our study were quite interesting: There were no signs of an increase in temporomandibular joint problems when the bone screw technique was used. However, slightly more alterations in the mandibular nerve were found. The relapse tendency, on the other hand, was minimal in cases in which bone screws were applied, in comparison with those in which wire osteosynthesis was used.
V
arious results after operative correction of mandibular prognathism show that there is some relapse, even in cases in which techniques with large bone contact in the split mandible are used. Spiessl’ was the first to transfer the principles of stable osteosynthesis from orthopedic surgery to the operative treatment of mandibular prognathism. Advantages of the bone screw fixation are a short period of intermaxillary immobilization and a primary bone healing as a prerequisite for a reduced relapse tendency. Schmoker and colleagues,2 Spiessl,3 and Hadjianghelou” reported good results and less relapse after bone screw fixation in sagittal split osteotomies. On the other hand, some controversies started about consequences of this type of osteosynthesis, mostly concerning pain and reduced function of the temporomandibular joint (TMJ). A higher percentage of disturbances of the mandibular nerve has been discussed, as well as alterations caused by corrosion or incompatibility of the bone screws. The aim of the present investigation was to compare the relapse tendency, disturbances of the mandibular nerve, and TMJ alterations after the use of wire
Table I. Subdivision of osteotomies in operative correction of mandibular prognathism
~~pr of .rurprJ’ Sagittal Vertical
split osteotom) osteotom)
Table II. Subdivision
tion of mandibular 7),pe
of fixation in operative correcprognathism Torul
(?f .jixurion
Wire osteosynthesis Screw ostcosynthesia _____--~~-~~
!
Follow-up 53
I I7 j@ 221
68 121
~-
osteosynthesis in one group of patients and bone screws in another group for the treatment of mandibular prognathism. MATERIALS
AND METHODS
At the Department of Oral and Maxillofacial Surgery of the University of Erlangen-Nuremberg, 221 cases of mandibular prognathism were treated by the techniques of sagittal split (146) and vertical osteotomy (75) between 1974 and 1980 (Table I). Bone fixation was achieved with wire osteosynthesis 00304220/X2/070002
+ 05500.50/O
63 19X2 The
C
V. Mosby
Co
Volume
Number
s4
Wire osteolysis vs. bone screws in mandibular prognathism
3
I
Fig. 1. Three bone screws are applied percutaneously osteotomy.
for fixation of the fragments in a sagittal split
Fig. 2. Radiographic view after vertical osteotomy and fixation of the overlapping bone screws on each side.
in 117 cases, whereas bone screw fixation 104 patients (Table II).
was used in
In the sagittal split osteotomy group wire osteosynthesis was done in 88 cases and bone screw fixation (Fig. 1) was applied in 58 patients (Table III). In the vertical osteotomy group wire osteosynthesis was used 29 times and bone screw fixation (Fig. 2) was performed in 46 cases (Table IV). Records and information were obtained by regular follow-up investigations; long-term results, approximately 2 years after the operation, could be established in 121 patients. To determine the relapse tendency in the different included preoperative, groups, our investigation immediate, and long-term postoperative cephalomet-
fragments with two
ric analysis as well as comparison of the cast models. Sagittal relapse was identified by a postoperative edge-to-edge or an anterior cross-bite position, whereas vertical relapse was defined as an edgeto-edge or open-bite position of the anterior teeth. In addition, postoperative changes in SNB and lower facial height were evaluated in order to determine the relapse tendency at the base of the mandible. Disturbances of the mandibular nerve were examined by tests with four stimuli: Scratching, needle puncture, exposure to cold, and warm water. The tests included not only the sensitivity of the skin in the lower lip-chin area but also the reaction of the mandibular teeth to frozen carbon dioxide. The function of the temporomandibular joint was
4 Paulus and Steinhauser Table
III. Type of fixation
Oral Surg. July. 1982
in sagittal split osteoto-
Table VII. Postoperative change of SNB (> 1 degree)
after sagittal osteotomy
mies
--/-xx 2 146
Wire osteosynthchis Screw ostcosynthesis
40 43
cases
TOid
Pet-C?tZl
Wire Screw
21 I6
40 43
53 37
83
Table IV. Type of fixation in vertical osteotomy Type of.frxation
Total
Wire osteosynthesib Screw osteosynthesis
29
13
46 75
25
Follow-up
Table VIII. Postoperative change of anterior facial height (> 1 mm.) after sagittal osteotomy Type oJ osrroq~nrhrsis
1
(hses 25 13
Wire Screw
38
Table V. Sagittal relapse (anterior edge-to-edge or cross-bite position) after sagittal osteotomy
Wire
c il.SC< 2 3
Screw ____-____-
Table VI. Vertical relapse (anterior edge-to-edge or open-bite position) after sagittal osteotomy Type of‘ostrosynthesis
C‘uses
Total
Wire Screw
6 2
40 43
Prrcmr I5 5
investigated by measuring the interincisal distance and the lateral and protrusive movements of the mandible. Noises and clicking, as well as TMJ pain, were compared with the preoperative findings. RESULTS
Following sagittal split osteotomies we found less relapse tendency in the group treated with bone screw fixation. When bone screws were used we observed sagittal relapse in 7 percent and vertical relapse in 5 percent, compared with 17.5 percent sagittal and 15 percent vertical relapse in cases with wire osteosynthesis (Tables V and VI). Postoperative change in SNB of more than 1 degree was seen in 21 of 40 cases (53 percent) treated with sagittal osteotomy and wire osteosynthesis and in 16 of 43 (37 percent) cases with bone screw fixation (Table VII). Postoperative increase in anterior facial height of more than 1 mm. could be established in 63 percent after wire osteosynthesis and in 30 percent after screw osteosynthesis (Table VIII).
PWCeni
TOtUl
40 43
-_____-
63 30
Table IX. Sagittal relapse (anterior edge-to-edge or cross-bite position) after vertical osteotomy Tj,pc oj o.\li’o.\ \~rrrhcsi.\
-____
~~~ ~~~~~~-
Type of ostrosynrhrsis
‘To/a/ 13 25 ~~~~~
Prrcen/ IS I6
Table X. Vertical relapse (anterior edge-to-edge or open-bite position) after vertical osteotomy ____Type of osrros~ilrhrsis Wire Screw
C’USP.F
Total
Pt-fYYJt11
I
13
x
4
2s
16
The percentage of relapse tendency after vertical osteotomies was even a little higher in cases with bone screw fixation than in those with wire osteosynthesis (Tables IX and X). Postoperative change in SNB was found in 3 of 13 patients (23 percent) with wire osteosynthesis and in 7 of 25 patients (28 percent) with bone screw fixation (Table XI). Postoperative increase in anterior facial height of more than 1 mm. could be observed in 38 percent after wire and in 24 percent after screw osteosynthesis (Table XIII). With both osteotomy techniques we found a high percentage of dysesthesias of the mandibular nerve immediately after the operation. We observed a great decrease in altered sensitivity in the first 6 months after the operation, and at the time of long-term follow-up there were just a few more nerve disturbances in the screw osteosynthesis group as compared with those treated by the wire technique. The conversion of altered to normal sensitivity is not as high after sagittal split osteotomies as after
Wire osteolysis vs. bone screws in mandibular prognathism
Volume 5-l Number
5
I
Table Xl. Postoperative change of SNB (> 1 degree)
after vertical osteotomy
XII. Postoperative increase of anterior facial height (> 1 mm.) after vertical osteotomy
Table
Type of osreosynthesis
Cases
Total
Percenl
Type of osteosynthesis
Cases
TOid
Percent
Wire Screw
3 7
13 25
23 28
Wire Screw
5 6
13 25
3x 24
Table XIII. Disturbances of sensibility
of the mandibular
Immediately (percent) Wire oateosynthesis Screw ostcosynthesis
Table XIV. Disturbances
87 90
of sensibility of the mandibular Immrdiatel~ (percent)
Wire osteosynthesis Screw ostcosynthesis
69 Xl
vertical osteotomies. In the long-term follow-up investigation, 50 percent of the sagittal osteotomies with wire osteosynthesis showed disturbances in sensitivity, as compared with 57 percent in the screw osteosynthesis group (Table XIII). After vertical osteotomies the relation between wire and screw osteosynthesis in regard to disturbances of sensitivity was 12: 16 percent (Table XIV). No major differences in TMJ alterations could be evaluated after wire and screw osteosynthesis with the sagittal split and the vertical osteotomy techniques. There was almost no change between preand postoperative noises, clicking, and function in both kinds of osteosynthesis. It is interesting that there is a decreased postoperative frequency of pain in the TMJ area in both groups (Tables XV to XVIII).
nerve after sagittal split osteotomy 6 mo.
I2 n,o.
(percent)
(percent]
62 64
60
51
nerve after vertical osteotomy 6 nro.
I2 n,o.
(percent)
(percenr)
IX 24
I5 19
Table XV. Pre- and long-term
postoperative disturbances of the temporomandibular joint after sagittal osteotomy and wire osteosynthesis Preoperative (pewem) Noises Clicking Pain Reduced
function
I3 45 13 I7
Table XVI. Pre- and long-term
postoperative disturbances of the temporomandibular joint after sagittal osteotomy and screw osteosynthesis Preoperative (percent)
DISCUSSION
Schmoker and colleagues2 also found a decreased relapse tendency in the treatment of mandibular prognathism after bone screw fixation. In their clinical follow-up study there were more relapses after the application of two bone screws than after insertion of three bone screws. Similar results could be observed in our study, where two screws in vertical osteotomies and three screws in sagittal osteotomies were routinely applied. The slightly higher tendency toward relapse after vertical osteotomy with screw osteosynthesis could also be related to those cases in which a counter-
I2 31 21 9
Lcurg-term fiA/ow-up (percenr/
Noises Clicking Pain Reduced
function
18 36 26 I
clockwise rotation of the mandible was carried out. In these cases a stable osteosynthesis with a short period of intermaxillary immobilization is nearly impossible because there is not sufficient overlapping bone. Under these circumstances, a sagittal split osteotomy with a three-point screw fixation is prefer-
6 Paulus and Steinhauser
Oral .surg. .lUl\1 19x2
Table XVII. Pre- and long-term postoperative disturbances of the temporomandibular joint after vertical osteotomy and wire osteosynthesis i-- ~~ lm,&-tcw11
I
Prropcrcrfl lpwl"'/rl
I‘(’
~
jid/m.-up
(p,rc c111J
I
application of bone screws in their experiments. According to our results, there seems to be a high degree of TMJ adaptability as long as the condyle is not displaced too extremely. Such a dislocation can be prevented when the right technique and the proper instruments are used.
I hUl\C\ C‘licking El / ” Rcduccd
function
IX 17 25 I0
I-1 31 IX IS
Table XVIII. Pre- and long-term postoperative distur-
bances of the temporomandibular joint after vertical osteotomy and screw osteosynthesis
Yoiac5 C‘licking Pain Rcduccd
function
able because it shows less relapse tendency. In our investigation we found only slightly more alterations in the mandibular nerve after bone screw fixation in both osteotomy techniques. It is obvious that in cases of sagittal split osteotomy the mandibular nerve can be damaged directly by the screw or by being strongly compressed by the fragments. After vertical osteotomy there is less danger of direct trauma. However, the mandibular nerve can also be damaged by coming too close to the lingula when a broad bone contact for the application of the screws is intended by the surgeon. At the time of the long-term followup investigation there were significantly more nerve disturbances after a sagittal split than after a vertical osteotomy. It must be emphasized, however, that, with the right instruments for exposure of the ascending ramus and for the percutaneous drilling, the risk of damaging the mandibular nerve is reduced. Animal studies of the reaction of the temporomandibular joint after the use of bone screw fixation were carried out at our institution by Sitzmann.5 His studies, as well as our long-term follow-up investigation, revealed no significant change in function, noises, clicking, and pain of the TMJ. Other investigators, as Freihofer’ and Tuinzing and Swart’ found changes in the position of the condyles after the
SUMMARY
A comparative study between wire and screw osteosynthesis was carried out in 121 patients who underwent operative treatment of mandibular prognathism at the Department of Oral and Maxillofacial Surgery of the University of ErlangenNuremberg between 1974 and 1980. The operative procedures included sagittal and vertical osteotomies of the ramus. The long-term results show that there is a slightly higher frequency of disturbances in the sensitivity of the mandibular nerve but no increase in TMJ alterations after the use of bone screws as compared with wire osteosynthesis. However, in view of the decreased relapse tendency and remarkable shortening of the period of intermaxillary fixation, it can be concluded that the application of bone screws in sagittal and vertical osteotomies represents an improvement in the operative treatment of mandibular prognathism. REFERENCES Spic\\t. H : C)\tco\!n~hesc bcl ag~ttaler O\tcotomic nach Ob~ccgacr Dal Ponl. t~‘url\chr.KicferGwcht\chir. 18: 145. I-IS. 1971 Schmoksr. H.. SpiceI. B.. and Gcnshelmcr. Th : kunktiow \~,~b~lc C)\~co\! nthe~ und Simulographic bcl dcr slgittnlcn Ostcotomic de\ aufhteigcndcn Ate\: Einc verglcichende kilni\chc I,ntersuchung. SSO 86: 5X2, 1976. Spiart. R: hew Concepts in Marillofacinl Boric SurgeI-y. Berlin. 1970. Sprlngcr Vcrlag. tlad.ji,lni.t”tott. 0.: Liirichcr F;rfahrungcn mlt der Zugschr:lllbCni)‘itCo~\.IllhC\t: bei dcr slgittatcn Spnltuns de, Ramua. t orl>chr.Kicfw Gesichtschir. 26: 94, 198 I. I:.- Klinische und tiercxperimentcllc CntersuSiL/mann, chungcn tibcr Kicfcrgelcnkveriindcrungcn nach korrcktivcn O\tcotomicn bcl Dycgnathicn, Fortschr.KicferGwichtschir. 26: 71. I9SI t.reihofct-. Ii. I’.: illodcll\crsuch fur I.agc\criindcrung de Kicfcrk$l’chcn\ nach sagit[aler Spaltung dcs Unterkicfcrs. sso x7: t 7. 1977. Tuinfing. I). H.. and Swart, G. I\.: Lclgevcr3nderungcn dc\ (‘;~pulmantlibul~~~ bei Vcrucndung van Zugschrauben nach agiltalcr O\tcolomie de\ Untcrkiefcrs. Dtsch.%ahn-. Mund-. hicfcr- (;c\icht\chir. 2: 93. t 97X.
V
arious results after operative correction of mandibular prognathism show that there is some relapse, even in cases in which techniques with large bone contact in the split mandible are used. Spiessl’ was the first to transfer the principles of stable osteosynthesis from orthopedic surgery to the operative treatment of mandibular prognathism. Advantages of the bone screw fixation are a short period of intermaxillary immobilization and a primary bone healing as a prerequisite for a reduced relapse tendency. Schmoker and colleagues,2 Spiessl,3 and Hadjianghelou” reported good results and less relapse after bone screw fixation in sagittal split osteotomies. On the other hand, some controversies started about consequences of this type of osteosynthesis, mostly concerning pain and reduced function of the temporomandibular joint (TMJ). A higher percentage of disturbances of the mandibular nerve has been discussed, as well as alterations caused by corrosion or incompatibility of the bone screws. The aim of the present investigation was to compare the relapse tendency, disturbances of the mandibular nerve, and TMJ alterations after the use of wire
Table I. Subdivision of osteotomies in operative correction of mandibular prognathism
~~pr of .rurprJ’ Sagittal Vertical
split osteotom) osteotom)
Table II. Subdivision
tion of mandibular 7),pe
of fixation in operative correcprognathism Torul
(?f .jixurion
Wire osteosynthesis Screw ostcosynthesia _____--~~-~~
!
Follow-up 53
I I7 j@ 221
68 121
~-
osteosynthesis in one group of patients and bone screws in another group for the treatment of mandibular prognathism. MATERIALS
AND METHODS
At the Department of Oral and Maxillofacial Surgery of the University of Erlangen-Nuremberg, 221 cases of mandibular prognathism were treated by the techniques of sagittal split (146) and vertical osteotomy (75) between 1974 and 1980 (Table I). Bone fixation was achieved with wire osteosynthesis 00304220/X2/070002
+ 05500.50/O
63 19X2 The
C
V. Mosby
Co
Volume
Number
s4
Wire osteolysis vs. bone screws in mandibular prognathism
3
I
Fig. 1. Three bone screws are applied percutaneously osteotomy.
for fixation of the fragments in a sagittal split
Fig. 2. Radiographic view after vertical osteotomy and fixation of the overlapping bone screws on each side.
in 117 cases, whereas bone screw fixation 104 patients (Table II).
was used in
In the sagittal split osteotomy group wire osteosynthesis was done in 88 cases and bone screw fixation (Fig. 1) was applied in 58 patients (Table III). In the vertical osteotomy group wire osteosynthesis was used 29 times and bone screw fixation (Fig. 2) was performed in 46 cases (Table IV). Records and information were obtained by regular follow-up investigations; long-term results, approximately 2 years after the operation, could be established in 121 patients. To determine the relapse tendency in the different included preoperative, groups, our investigation immediate, and long-term postoperative cephalomet-
fragments with two
ric analysis as well as comparison of the cast models. Sagittal relapse was identified by a postoperative edge-to-edge or an anterior cross-bite position, whereas vertical relapse was defined as an edgeto-edge or open-bite position of the anterior teeth. In addition, postoperative changes in SNB and lower facial height were evaluated in order to determine the relapse tendency at the base of the mandible. Disturbances of the mandibular nerve were examined by tests with four stimuli: Scratching, needle puncture, exposure to cold, and warm water. The tests included not only the sensitivity of the skin in the lower lip-chin area but also the reaction of the mandibular teeth to frozen carbon dioxide. The function of the temporomandibular joint was
4 Paulus and Steinhauser Table
III. Type of fixation
Oral Surg. July. 1982
in sagittal split osteoto-
Table VII. Postoperative change of SNB (> 1 degree)
after sagittal osteotomy
mies
--/-xx 2 146
Wire osteosynthchis Screw ostcosynthesis
40 43
cases
TOid
Pet-C?tZl
Wire Screw
21 I6
40 43
53 37
83
Table IV. Type of fixation in vertical osteotomy Type of.frxation
Total
Wire osteosynthesib Screw osteosynthesis
29
13
46 75
25
Follow-up
Table VIII. Postoperative change of anterior facial height (> 1 mm.) after sagittal osteotomy Type oJ osrroq~nrhrsis
1
(hses 25 13
Wire Screw
38
Table V. Sagittal relapse (anterior edge-to-edge or cross-bite position) after sagittal osteotomy
Wire
c il.SC< 2 3
Screw ____-____-
Table VI. Vertical relapse (anterior edge-to-edge or open-bite position) after sagittal osteotomy Type of‘ostrosynthesis
C‘uses
Total
Wire Screw
6 2
40 43
Prrcmr I5 5
investigated by measuring the interincisal distance and the lateral and protrusive movements of the mandible. Noises and clicking, as well as TMJ pain, were compared with the preoperative findings. RESULTS
Following sagittal split osteotomies we found less relapse tendency in the group treated with bone screw fixation. When bone screws were used we observed sagittal relapse in 7 percent and vertical relapse in 5 percent, compared with 17.5 percent sagittal and 15 percent vertical relapse in cases with wire osteosynthesis (Tables V and VI). Postoperative change in SNB of more than 1 degree was seen in 21 of 40 cases (53 percent) treated with sagittal osteotomy and wire osteosynthesis and in 16 of 43 (37 percent) cases with bone screw fixation (Table VII). Postoperative increase in anterior facial height of more than 1 mm. could be established in 63 percent after wire osteosynthesis and in 30 percent after screw osteosynthesis (Table VIII).
PWCeni
TOtUl
40 43
-_____-
63 30
Table IX. Sagittal relapse (anterior edge-to-edge or cross-bite position) after vertical osteotomy Tj,pc oj o.\li’o.\ \~rrrhcsi.\
-____
~~~ ~~~~~~-
Type of ostrosynrhrsis
‘To/a/ 13 25 ~~~~~
Prrcen/ IS I6
Table X. Vertical relapse (anterior edge-to-edge or open-bite position) after vertical osteotomy ____Type of osrros~ilrhrsis Wire Screw
C’USP.F
Total
Pt-fYYJt11
I
13
x
4
2s
16
The percentage of relapse tendency after vertical osteotomies was even a little higher in cases with bone screw fixation than in those with wire osteosynthesis (Tables IX and X). Postoperative change in SNB was found in 3 of 13 patients (23 percent) with wire osteosynthesis and in 7 of 25 patients (28 percent) with bone screw fixation (Table XI). Postoperative increase in anterior facial height of more than 1 mm. could be observed in 38 percent after wire and in 24 percent after screw osteosynthesis (Table XIII). With both osteotomy techniques we found a high percentage of dysesthesias of the mandibular nerve immediately after the operation. We observed a great decrease in altered sensitivity in the first 6 months after the operation, and at the time of long-term follow-up there were just a few more nerve disturbances in the screw osteosynthesis group as compared with those treated by the wire technique. The conversion of altered to normal sensitivity is not as high after sagittal split osteotomies as after
Wire osteolysis vs. bone screws in mandibular prognathism
Volume 5-l Number
5
I
Table Xl. Postoperative change of SNB (> 1 degree)
after vertical osteotomy
XII. Postoperative increase of anterior facial height (> 1 mm.) after vertical osteotomy
Table
Type of osreosynthesis
Cases
Total
Percenl
Type of osteosynthesis
Cases
TOid
Percent
Wire Screw
3 7
13 25
23 28
Wire Screw
5 6
13 25
3x 24
Table XIII. Disturbances of sensibility
of the mandibular
Immediately (percent) Wire oateosynthesis Screw ostcosynthesis
Table XIV. Disturbances
87 90
of sensibility of the mandibular Immrdiatel~ (percent)
Wire osteosynthesis Screw ostcosynthesis
69 Xl
vertical osteotomies. In the long-term follow-up investigation, 50 percent of the sagittal osteotomies with wire osteosynthesis showed disturbances in sensitivity, as compared with 57 percent in the screw osteosynthesis group (Table XIII). After vertical osteotomies the relation between wire and screw osteosynthesis in regard to disturbances of sensitivity was 12: 16 percent (Table XIV). No major differences in TMJ alterations could be evaluated after wire and screw osteosynthesis with the sagittal split and the vertical osteotomy techniques. There was almost no change between preand postoperative noises, clicking, and function in both kinds of osteosynthesis. It is interesting that there is a decreased postoperative frequency of pain in the TMJ area in both groups (Tables XV to XVIII).
nerve after sagittal split osteotomy 6 mo.
I2 n,o.
(percent)
(percent]
62 64
60
51
nerve after vertical osteotomy 6 nro.
I2 n,o.
(percent)
(percenr)
IX 24
I5 19
Table XV. Pre- and long-term
postoperative disturbances of the temporomandibular joint after sagittal osteotomy and wire osteosynthesis Preoperative (pewem) Noises Clicking Pain Reduced
function
I3 45 13 I7
Table XVI. Pre- and long-term
postoperative disturbances of the temporomandibular joint after sagittal osteotomy and screw osteosynthesis Preoperative (percent)
DISCUSSION
Schmoker and colleagues2 also found a decreased relapse tendency in the treatment of mandibular prognathism after bone screw fixation. In their clinical follow-up study there were more relapses after the application of two bone screws than after insertion of three bone screws. Similar results could be observed in our study, where two screws in vertical osteotomies and three screws in sagittal osteotomies were routinely applied. The slightly higher tendency toward relapse after vertical osteotomy with screw osteosynthesis could also be related to those cases in which a counter-
I2 31 21 9
Lcurg-term fiA/ow-up (percenr/
Noises Clicking Pain Reduced
function
18 36 26 I
clockwise rotation of the mandible was carried out. In these cases a stable osteosynthesis with a short period of intermaxillary immobilization is nearly impossible because there is not sufficient overlapping bone. Under these circumstances, a sagittal split osteotomy with a three-point screw fixation is prefer-
6 Paulus and Steinhauser
Oral .surg. .lUl\1 19x2
Table XVII. Pre- and long-term postoperative disturbances of the temporomandibular joint after vertical osteotomy and wire osteosynthesis i-- ~~ lm,&-tcw11
I
Prropcrcrfl lpwl"'/rl
I‘(’
~
jid/m.-up
(p,rc c111J
I
application of bone screws in their experiments. According to our results, there seems to be a high degree of TMJ adaptability as long as the condyle is not displaced too extremely. Such a dislocation can be prevented when the right technique and the proper instruments are used.
I hUl\C\ C‘licking El / ” Rcduccd
function
IX 17 25 I0
I-1 31 IX IS
Table XVIII. Pre- and long-term postoperative distur-
bances of the temporomandibular joint after vertical osteotomy and screw osteosynthesis
Yoiac5 C‘licking Pain Rcduccd
function
able because it shows less relapse tendency. In our investigation we found only slightly more alterations in the mandibular nerve after bone screw fixation in both osteotomy techniques. It is obvious that in cases of sagittal split osteotomy the mandibular nerve can be damaged directly by the screw or by being strongly compressed by the fragments. After vertical osteotomy there is less danger of direct trauma. However, the mandibular nerve can also be damaged by coming too close to the lingula when a broad bone contact for the application of the screws is intended by the surgeon. At the time of the long-term followup investigation there were significantly more nerve disturbances after a sagittal split than after a vertical osteotomy. It must be emphasized, however, that, with the right instruments for exposure of the ascending ramus and for the percutaneous drilling, the risk of damaging the mandibular nerve is reduced. Animal studies of the reaction of the temporomandibular joint after the use of bone screw fixation were carried out at our institution by Sitzmann.5 His studies, as well as our long-term follow-up investigation, revealed no significant change in function, noises, clicking, and pain of the TMJ. Other investigators, as Freihofer’ and Tuinzing and Swart’ found changes in the position of the condyles after the
SUMMARY
A comparative study between wire and screw osteosynthesis was carried out in 121 patients who underwent operative treatment of mandibular prognathism at the Department of Oral and Maxillofacial Surgery of the University of ErlangenNuremberg between 1974 and 1980. The operative procedures included sagittal and vertical osteotomies of the ramus. The long-term results show that there is a slightly higher frequency of disturbances in the sensitivity of the mandibular nerve but no increase in TMJ alterations after the use of bone screws as compared with wire osteosynthesis. However, in view of the decreased relapse tendency and remarkable shortening of the period of intermaxillary fixation, it can be concluded that the application of bone screws in sagittal and vertical osteotomies represents an improvement in the operative treatment of mandibular prognathism. REFERENCES Spic\\t. H : C)\tco\!n~hesc bcl ag~ttaler O\tcotomic nach Ob~ccgacr Dal Ponl. t~‘url\chr.KicferGwcht\chir. 18: 145. I-IS. 1971 Schmoksr. H.. SpiceI. B.. and Gcnshelmcr. Th : kunktiow \~,~b~lc C)\~co\! nthe~ und Simulographic bcl dcr slgittnlcn Ostcotomic de\ aufhteigcndcn Ate\: Einc verglcichende kilni\chc I,ntersuchung. SSO 86: 5X2, 1976. Spiart. R: hew Concepts in Marillofacinl Boric SurgeI-y. Berlin. 1970. Sprlngcr Vcrlag. tlad.ji,lni.t”tott. 0.: Liirichcr F;rfahrungcn mlt der Zugschr:lllbCni)‘itCo~\.IllhC\t: bei dcr slgittatcn Spnltuns de, Ramua. t orl>chr.Kicfw Gesichtschir. 26: 94, 198 I. I:.- Klinische und tiercxperimentcllc CntersuSiL/mann, chungcn tibcr Kicfcrgelcnkveriindcrungcn nach korrcktivcn O\tcotomicn bcl Dycgnathicn, Fortschr.KicferGwichtschir. 26: 71. I9SI t.reihofct-. Ii. I’.: illodcll\crsuch fur I.agc\criindcrung de Kicfcrk$l’chcn\ nach sagit[aler Spaltung dcs Unterkicfcrs. sso x7: t 7. 1977. Tuinfing. I). H.. and Swart, G. I\.: Lclgevcr3nderungcn dc\ (‘;~pulmantlibul~~~ bei Vcrucndung van Zugschrauben nach agiltalcr O\tcolomie de\ Untcrkiefcrs. Dtsch.%ahn-. Mund-. hicfcr- (;c\icht\chir. 2: 93. t 97X.