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Clinical trial of pantomography for the evaluation of mandibular trauma
ORIGINAL C.ONTRIBUTION
Clinical Trial of Pantomography For the Evaluation of Mandibular Trauma Charles C. Johnston, MD* Peter E. Doris, MD *t Chicago, Illinois
A trial study was conducted comparing the standard "four view" mandibular series and pantomography for the evaluation of mandibular trauma. During the six-month trial period a series of 17 patients with a total of 24 mandibular fractures was compiled. The pantomographs were more easily interpreted than the standard views because overlapping structures were blurred and spatial orientation was clear. In eight of the 17 patients the fractures were more clearly visualized by pantomography. Because the entire mandible was seen so well on the pantomographs, no special views were required. Eleven patients had single fractures, which are in fact quite common. Johnston CC, Doris PE: Clinical trial of pantomography for the evaluation o f mandibular trauma. Ann Emerg Med 9:415-418, August 1980.
injury, mandible, evaluation by pantomography; mandibular trauma, detection, pantomography; pantomography, mandibular trauma; radiography, pantomography, detection of mandibular trauma INTRODUCTION
The m a n d i b l e is one of the most frequently fractured facial bones. 1 The conv e n t i o n a l '~four view" m a n d i b u l a r series (right oblique, left oblique, anteriorposterior mental, a n d Towne's view of the t e m p o r o m a n d i b u l a r joints) at times is difficult to i n t e r p r e t and m a y not show all fractures clearly. The pantomographic technique of m a n d i b u l a r r a d i o g r a p h y has been refined in the p a s t few y e a r s a n d offers distinct a d v a n t a g e s for d e m o n s t r a t i n g fractures. This report describes a comparison study of s t a n d a r d films and p a n t o m o g r a p h y for the e v a l u a t i o n of m a n d i b u l a r fractures. MATERIALS AND METHODS
Mandibular pantomography employs the basic tomographic principle: s i m u l t a n e o u s m o v e m e n t of the b e a m source and the film blurs all structures except those in a specific plane. In m a n d i b u l a r p a n t o m o g r a p h y , the x-ray tube a n d the film cassette r o t a t e about the p a t i e n t ' s h e a d in an elliptical p a t h to produce a p l a n e of focus r o u g h l y one c e n t i m e t e r thick along the arch of the m a n d i b l e (Figures 1 and 2). O v e r l y i n g structures, such as the cervical spine, are b l u r r e d out. 2 The system used in our study (General Electric ~Panelipse") allows precise a d j u s t m e n t of the focal p l a n e to fit a m a n d i b l e of a n y size. This f e a t u r e results in significantly less i m a g e b l u r r i n g and size distortion. The entire m a n d i b l e is s p l a y e d out as a continuous s t r u c t u r e and uniformly magnified 19%. From theDepartments of Emergency Medicine* and Radiology,t University of Chicago Medical School, Chicago, Illinois; and Good Samaritan Hospital, Downer's Grove, Illinois. Address for reprints: Charles C. Johnston, MD, Department of Emergency and Ambulatory Medicine, William Beaumont Hospital, Thirteen Mile Road, Royal Oak, Michigan 48072.
9:8 (August) 1980
Ann
Emerg Med
415/35
P a t i e n t cooperation is essential for adequate pantomographs. The pat i e n t m u s t be able to sit u p r i g h t in a c h a i r or stretcher and bite on a cent e r i n g guide for the exposure period (22 sec). The r a d i a t i o n dose from a s i n g l e p a n t o m o g r a p h is 500 m r a d s (General Electric Medical Systems), c o m p a r e d to a p p r o x i m a t e l y 1,000 m r a d s for a ~four view" m a n d i b u l a r series. 3 Sixty m a n d i b u l a r e x a m i n a t i o n s were requested during the study p e r i o d ( J u l y to D e c e m b e r 1979). B e c a u s e t h e p a n t o m o g r a p h i c technique was not proven for the demons t r a t i o n of fractures, both s t a n d a r d ~four view" films and pantomographic films were taken when a m a n d i b u l a r series was requested by t h e e m e r g e n c y physician. All films w e r e r e v i e w e d a n d t h e e a s e of int e r p r e t a t i o n was noted.
RESULTS Seventeen patients had mand i b u l a r fractures. Nine p a t i e n t s were m e n and eight were women. The patients were predominantly young a d u l t s (Table). E l e v e n p a t i e n t s h a d a s i n g l e f r a c t u r e ; five h a d two fractures; and one p a t i e n t h a d t h r e e fractures (total n u m b e r of fractures: 24). T h e l o c a t i o n s of t h e f r a c t u r e s a r e shown (Figure 3). In eight of the 17 p a t i e n t s (47%) the m a n d i b u l a r fract u r e s w e r e m o r e c l e a r l y s h o w n in p a n t o m o g r a p h y (Figures 4 and 5).
\
\
\
\
\
\
F i g . 1. Patient position for pantomography with General Electric "Panelipse "~. The patient sits upright and bites on a bite guide (A). The x-ray beam (B) is directed through the patient from one side while recording the image of the mandible closest to the side of the film drum (C).
DISCUSSION I n t e r p r e t a t i o n of t h e s t a n d a r d ~four view" m a n d i b u l a r series m a y be difficult for both the e m e r g e n c y p h y s i c i a n and the radiologist because of o v e r l a p p i n g bones and confusing spatial relationships. Furthermore, the x - r a y b e a m m a y not be p a r a l l e l to t h e f r a c t u r e l i n e . I f t h e b e a m s t r i k e s a m i n i m a l l y d i s p l a c e d fract u r e obliquely, the fracture m a y be
J
Table TECHNIQUE CONSIDERED TO SHOW FRACTURES MORE CLEARLY Technique
No.
Pantomography 8 Standard "four view" series 0 Neither technique considered superior 9 Total
36/416
17
% 48
0 52 100
F i g . 2 The pantomography mechanism. The x-ray beam (A) rotates around a continuously moving center of rotation. This center of rotation moves along an elliptical path that matches the contour of the mandible. The film drum (B) turns so that the amount of film exposed corresponds to the length of the path traveled.
Ann
Emerg Med
9:8 (August) 1980
Condylor8t Subcondylor-8
~
L
~
Symphysis-4
Fig. 3. Location of mandibular fractures (17 patients, 24 fractures).
I0 O9 I-Z
7
LU
Hi
n
O-IO
3 N IO-20 20-50 50-40 >40 2 N
AGE
Fig. 4. Age distribution of patients. Nearly all were in the young adult age group of teens to forties.
~ (f~
//~
Subcondyelr-I
,Condylar 8~
~
Symphysis5
SUMMARY
Fig, 5. Location of fractures shown best by pantomography. Of four syrnphysis
fractures, three were shown better by pantomography. 9:8 (August) 1980
poorly seen or not demonstrated on the film. Condylar fractures m a y be p a r t i c u l a r l y difficult to demonstrate on s t a n d a r d films, and special views of the t e m p o r o m a n d i b u l a r joints m a y be required.I, 4 Because fractures in this area are difficult to localize on physical examination, the initial physician may fail to request the required studies. Our clinical t r i a l o f pantomography demonstrates the advantages of the technique. Overlapping struct u r e s were b l u r r e d out and spatial o r i e n t a t i o n was clear. In m a n y patients the fractures were grossly evident by both methods, b u t in eight of the 17 patients there were fractures which were more clearly visualized by pantomography (Figures 6-8). One condylar fracture was well visualized by pantomography and demonstrated only in retrospect on the "four view" m a n d i b u l a r series ( F i g u r e 9). The temporomandibular joints were visualized so well by pantomography t h a t a d d i t i o n a l views were not required in any instance. Only severely t r a u m a t i z e d pat i e n t s were u n a b l e to c o o p e r a t e adequately for pantomography, and in these patients the identification of a mandible fracture was of low priority. The age incidence and location of f r a c t u r e s in our series were comparable to other studies. Most m a n d i b u lar fractures occur in the active adult age group of teens to forties. 5-7 Fractures of the body, angle and condylar region are frequent, while fractures of the r a m u s and alveolar region are less frequent.5, 7 E a r l i e r s t u d i e s ~-7 report a 3:1 male preponderance among patients with m a n d i b u l a r f r a c t u r e s , b u t i n our series the sex ratio was nearly equal. This may be a reflection of the g r e a t e r percentage of motor vehicle accidents as a cause of m a n d i b u l a r t r a u m a in our population. I n 11 of our 17 p a t i e n t s (65%) there was only a single fracture. A s t a n d a r d radiology text states: ~A single fracture to the lower j a w is found at times; however, it is more common to find two or more resulting from injury. ''s The oral surgery l i t e r a t u r e states t h a t single fractures are as frequent as double and multiple fractures combined. ~-7 The reason for this apparent contradiction is not clear.
Ann
Emerg Med
The v a l u e of m a n d i b u l a r p a n tomography in the t r a u m a t i z e d pat i e n t is e v i d e n t from this c l i n i c a l
417/37
Fig. 6A, Patient CF, standard left oblique view (magnified). A fracture of the left mandibular angle is barely visible on this standard view (arrow).
F i g . 7 B . Patient RG, pantomograph. The fracture of the symphysis is well visualized (arrow). Overlapping bony structures are blurred out by the pantomographic technique.
F i g . 9B. Patient JL, pantomograph.
The right subcondylar fracture is well visualized (arrow). trial. Our experience suggests that mandibular pantomography may w e l l s u p p l a n t t h e n e e d to o b t a i n a s t a n d a r d " f o u r v i e w " m a n d i b u l a r series. M a n d i b u l a r f r a c t u r e s a r e m o s t common in young adults and are often single fractures. The authors t h a n k Lois Adams, Vicki L. Miller, RT, a n d P a u l Gaebel for t h e i r technical assistance; Martin Hochhauser, MD, for his e n c o u r a g e m e n t ; a n d Good S a m a r i t a n Hospital for its support.
REFERENCES 1. Paul LW, J u h l JH: The Essentials of Roentgen Interpretation. New York, Harper & Row, 1965, p 876. F i g . 6 B . Patient CF, pantomograph.
F i g . 8. Patient LM, pantomograph.
The fracture of the left mandibular angle is well visualized (arrow A). There is also a fracture of the right mandibular body (arrow B) that is shown well by both techniques.
A n uncommon fracture of the alveolar ridge is well visualized by pantomography. This fracture is not demonstrated on the standard "four view" mandibular series.
2. Smith CJ, Fleming RD: A comprehensive review of n o r m a l a n a t o m i c landm a r k s a n d a r t i f a c t s as v i s u a l i z e d on P a n o r e x r a d i o g r a p h s . J Oral Surg 37:291-304, 1974. 3. Rogers RT: Radiation dose to the skin in diagnostic radiography. Br J Radiol 42:511-518, 1969. 4. Blevins C, Gores RJ: Fractures of the m a n d i b u l a r condyloid process: results of conservative t r e a t m e n t in 140 patients. J
Oral Surg, Anesth, Hosp Dent Serv 19: 392-407, 1961. 5. Hogan EH, Huelke DF: An analysis of 319 case reports of m a n d i b u l a r fractures.
J Oral Surg, Anesth, Hosp Dent Serv 19:93-104, 1961. 6. Melmed EP, Koonin AJ: Fractures of the mandible: a review of 909 cases. Plast Reconstr Surg 56:323-327, 1975.
9 A . P a t i e n t JL, s t a n d a r d Towne's view of the temporomandibular joints. A right subcondylar fracture (arrow) is partially obscured by the mastoid process. Fig.
Fig. 7A. Patient RG, standard anterior-posterior mental view. A fracture involving the symphysis is obscured by overlapping bony structures.
38/418
Ann Emerg Med
7. Goldberg MG, Williams AC: The location and occurrence of m a n d i b u l a r fractures: an analysis of 202 cases. Oral Surg 28:336-341, 1969. 8. Stafne EC, Gibilisco JA: Oral Roentgenographic Diagnosis. Philadelphia, WB Saunders, 1975, p 338.
9:8 (August) 1980
Clinical Trial of Pantomography For the Evaluation of Mandibular Trauma Charles C. Johnston, MD* Peter E. Doris, MD *t Chicago, Illinois
A trial study was conducted comparing the standard "four view" mandibular series and pantomography for the evaluation of mandibular trauma. During the six-month trial period a series of 17 patients with a total of 24 mandibular fractures was compiled. The pantomographs were more easily interpreted than the standard views because overlapping structures were blurred and spatial orientation was clear. In eight of the 17 patients the fractures were more clearly visualized by pantomography. Because the entire mandible was seen so well on the pantomographs, no special views were required. Eleven patients had single fractures, which are in fact quite common. Johnston CC, Doris PE: Clinical trial of pantomography for the evaluation o f mandibular trauma. Ann Emerg Med 9:415-418, August 1980.
injury, mandible, evaluation by pantomography; mandibular trauma, detection, pantomography; pantomography, mandibular trauma; radiography, pantomography, detection of mandibular trauma INTRODUCTION
The m a n d i b l e is one of the most frequently fractured facial bones. 1 The conv e n t i o n a l '~four view" m a n d i b u l a r series (right oblique, left oblique, anteriorposterior mental, a n d Towne's view of the t e m p o r o m a n d i b u l a r joints) at times is difficult to i n t e r p r e t and m a y not show all fractures clearly. The pantomographic technique of m a n d i b u l a r r a d i o g r a p h y has been refined in the p a s t few y e a r s a n d offers distinct a d v a n t a g e s for d e m o n s t r a t i n g fractures. This report describes a comparison study of s t a n d a r d films and p a n t o m o g r a p h y for the e v a l u a t i o n of m a n d i b u l a r fractures. MATERIALS AND METHODS
Mandibular pantomography employs the basic tomographic principle: s i m u l t a n e o u s m o v e m e n t of the b e a m source and the film blurs all structures except those in a specific plane. In m a n d i b u l a r p a n t o m o g r a p h y , the x-ray tube a n d the film cassette r o t a t e about the p a t i e n t ' s h e a d in an elliptical p a t h to produce a p l a n e of focus r o u g h l y one c e n t i m e t e r thick along the arch of the m a n d i b l e (Figures 1 and 2). O v e r l y i n g structures, such as the cervical spine, are b l u r r e d out. 2 The system used in our study (General Electric ~Panelipse") allows precise a d j u s t m e n t of the focal p l a n e to fit a m a n d i b l e of a n y size. This f e a t u r e results in significantly less i m a g e b l u r r i n g and size distortion. The entire m a n d i b l e is s p l a y e d out as a continuous s t r u c t u r e and uniformly magnified 19%. From theDepartments of Emergency Medicine* and Radiology,t University of Chicago Medical School, Chicago, Illinois; and Good Samaritan Hospital, Downer's Grove, Illinois. Address for reprints: Charles C. Johnston, MD, Department of Emergency and Ambulatory Medicine, William Beaumont Hospital, Thirteen Mile Road, Royal Oak, Michigan 48072.
9:8 (August) 1980
Ann
Emerg Med
415/35
P a t i e n t cooperation is essential for adequate pantomographs. The pat i e n t m u s t be able to sit u p r i g h t in a c h a i r or stretcher and bite on a cent e r i n g guide for the exposure period (22 sec). The r a d i a t i o n dose from a s i n g l e p a n t o m o g r a p h is 500 m r a d s (General Electric Medical Systems), c o m p a r e d to a p p r o x i m a t e l y 1,000 m r a d s for a ~four view" m a n d i b u l a r series. 3 Sixty m a n d i b u l a r e x a m i n a t i o n s were requested during the study p e r i o d ( J u l y to D e c e m b e r 1979). B e c a u s e t h e p a n t o m o g r a p h i c technique was not proven for the demons t r a t i o n of fractures, both s t a n d a r d ~four view" films and pantomographic films were taken when a m a n d i b u l a r series was requested by t h e e m e r g e n c y physician. All films w e r e r e v i e w e d a n d t h e e a s e of int e r p r e t a t i o n was noted.
RESULTS Seventeen patients had mand i b u l a r fractures. Nine p a t i e n t s were m e n and eight were women. The patients were predominantly young a d u l t s (Table). E l e v e n p a t i e n t s h a d a s i n g l e f r a c t u r e ; five h a d two fractures; and one p a t i e n t h a d t h r e e fractures (total n u m b e r of fractures: 24). T h e l o c a t i o n s of t h e f r a c t u r e s a r e shown (Figure 3). In eight of the 17 p a t i e n t s (47%) the m a n d i b u l a r fract u r e s w e r e m o r e c l e a r l y s h o w n in p a n t o m o g r a p h y (Figures 4 and 5).
\
\
\
\
\
\
F i g . 1. Patient position for pantomography with General Electric "Panelipse "~. The patient sits upright and bites on a bite guide (A). The x-ray beam (B) is directed through the patient from one side while recording the image of the mandible closest to the side of the film drum (C).
DISCUSSION I n t e r p r e t a t i o n of t h e s t a n d a r d ~four view" m a n d i b u l a r series m a y be difficult for both the e m e r g e n c y p h y s i c i a n and the radiologist because of o v e r l a p p i n g bones and confusing spatial relationships. Furthermore, the x - r a y b e a m m a y not be p a r a l l e l to t h e f r a c t u r e l i n e . I f t h e b e a m s t r i k e s a m i n i m a l l y d i s p l a c e d fract u r e obliquely, the fracture m a y be
J
Table TECHNIQUE CONSIDERED TO SHOW FRACTURES MORE CLEARLY Technique
No.
Pantomography 8 Standard "four view" series 0 Neither technique considered superior 9 Total
36/416
17
% 48
0 52 100
F i g . 2 The pantomography mechanism. The x-ray beam (A) rotates around a continuously moving center of rotation. This center of rotation moves along an elliptical path that matches the contour of the mandible. The film drum (B) turns so that the amount of film exposed corresponds to the length of the path traveled.
Ann
Emerg Med
9:8 (August) 1980
Condylor8t Subcondylor-8
~
L
~
Symphysis-4
Fig. 3. Location of mandibular fractures (17 patients, 24 fractures).
I0 O9 I-Z
7
LU
Hi
n
O-IO
3 N IO-20 20-50 50-40 >40 2 N
AGE
Fig. 4. Age distribution of patients. Nearly all were in the young adult age group of teens to forties.
~ (f~
//~
Subcondyelr-I
,Condylar 8~
~
Symphysis5
SUMMARY
Fig, 5. Location of fractures shown best by pantomography. Of four syrnphysis
fractures, three were shown better by pantomography. 9:8 (August) 1980
poorly seen or not demonstrated on the film. Condylar fractures m a y be p a r t i c u l a r l y difficult to demonstrate on s t a n d a r d films, and special views of the t e m p o r o m a n d i b u l a r joints m a y be required.I, 4 Because fractures in this area are difficult to localize on physical examination, the initial physician may fail to request the required studies. Our clinical t r i a l o f pantomography demonstrates the advantages of the technique. Overlapping struct u r e s were b l u r r e d out and spatial o r i e n t a t i o n was clear. In m a n y patients the fractures were grossly evident by both methods, b u t in eight of the 17 patients there were fractures which were more clearly visualized by pantomography (Figures 6-8). One condylar fracture was well visualized by pantomography and demonstrated only in retrospect on the "four view" m a n d i b u l a r series ( F i g u r e 9). The temporomandibular joints were visualized so well by pantomography t h a t a d d i t i o n a l views were not required in any instance. Only severely t r a u m a t i z e d pat i e n t s were u n a b l e to c o o p e r a t e adequately for pantomography, and in these patients the identification of a mandible fracture was of low priority. The age incidence and location of f r a c t u r e s in our series were comparable to other studies. Most m a n d i b u lar fractures occur in the active adult age group of teens to forties. 5-7 Fractures of the body, angle and condylar region are frequent, while fractures of the r a m u s and alveolar region are less frequent.5, 7 E a r l i e r s t u d i e s ~-7 report a 3:1 male preponderance among patients with m a n d i b u l a r f r a c t u r e s , b u t i n our series the sex ratio was nearly equal. This may be a reflection of the g r e a t e r percentage of motor vehicle accidents as a cause of m a n d i b u l a r t r a u m a in our population. I n 11 of our 17 p a t i e n t s (65%) there was only a single fracture. A s t a n d a r d radiology text states: ~A single fracture to the lower j a w is found at times; however, it is more common to find two or more resulting from injury. ''s The oral surgery l i t e r a t u r e states t h a t single fractures are as frequent as double and multiple fractures combined. ~-7 The reason for this apparent contradiction is not clear.
Ann
Emerg Med
The v a l u e of m a n d i b u l a r p a n tomography in the t r a u m a t i z e d pat i e n t is e v i d e n t from this c l i n i c a l
417/37
Fig. 6A, Patient CF, standard left oblique view (magnified). A fracture of the left mandibular angle is barely visible on this standard view (arrow).
F i g . 7 B . Patient RG, pantomograph. The fracture of the symphysis is well visualized (arrow). Overlapping bony structures are blurred out by the pantomographic technique.
F i g . 9B. Patient JL, pantomograph.
The right subcondylar fracture is well visualized (arrow). trial. Our experience suggests that mandibular pantomography may w e l l s u p p l a n t t h e n e e d to o b t a i n a s t a n d a r d " f o u r v i e w " m a n d i b u l a r series. M a n d i b u l a r f r a c t u r e s a r e m o s t common in young adults and are often single fractures. The authors t h a n k Lois Adams, Vicki L. Miller, RT, a n d P a u l Gaebel for t h e i r technical assistance; Martin Hochhauser, MD, for his e n c o u r a g e m e n t ; a n d Good S a m a r i t a n Hospital for its support.
REFERENCES 1. Paul LW, J u h l JH: The Essentials of Roentgen Interpretation. New York, Harper & Row, 1965, p 876. F i g . 6 B . Patient CF, pantomograph.
F i g . 8. Patient LM, pantomograph.
The fracture of the left mandibular angle is well visualized (arrow A). There is also a fracture of the right mandibular body (arrow B) that is shown well by both techniques.
A n uncommon fracture of the alveolar ridge is well visualized by pantomography. This fracture is not demonstrated on the standard "four view" mandibular series.
2. Smith CJ, Fleming RD: A comprehensive review of n o r m a l a n a t o m i c landm a r k s a n d a r t i f a c t s as v i s u a l i z e d on P a n o r e x r a d i o g r a p h s . J Oral Surg 37:291-304, 1974. 3. Rogers RT: Radiation dose to the skin in diagnostic radiography. Br J Radiol 42:511-518, 1969. 4. Blevins C, Gores RJ: Fractures of the m a n d i b u l a r condyloid process: results of conservative t r e a t m e n t in 140 patients. J
Oral Surg, Anesth, Hosp Dent Serv 19: 392-407, 1961. 5. Hogan EH, Huelke DF: An analysis of 319 case reports of m a n d i b u l a r fractures.
J Oral Surg, Anesth, Hosp Dent Serv 19:93-104, 1961. 6. Melmed EP, Koonin AJ: Fractures of the mandible: a review of 909 cases. Plast Reconstr Surg 56:323-327, 1975.
9 A . P a t i e n t JL, s t a n d a r d Towne's view of the temporomandibular joints. A right subcondylar fracture (arrow) is partially obscured by the mastoid process. Fig.
Fig. 7A. Patient RG, standard anterior-posterior mental view. A fracture involving the symphysis is obscured by overlapping bony structures.
38/418
Ann Emerg Med
7. Goldberg MG, Williams AC: The location and occurrence of m a n d i b u l a r fractures: an analysis of 202 cases. Oral Surg 28:336-341, 1969. 8. Stafne EC, Gibilisco JA: Oral Roentgenographic Diagnosis. Philadelphia, WB Saunders, 1975, p 338.
9:8 (August) 1980