- Email: [email protected]
Bilateral hyperplasia of the mandibular coronoid process
Bilateral hyperplasia of the mandibular coronoid process Barry N. Fitzpatrick, M.D.Xc. Adelaide, South Australia Nowhere in the annals of a joint long
surgery
is
(W.A.),
there
to
P.D.S.R.C.S.
be
found
proof
(Ens.),”
that
Test
can
anchylose
....
The Fakirs of India as they have no desire
have joints, which. are to
use
them,
the joints
stiff
from
remain
stiff
prolonged
d&se,
and as
. . . .
-Hugh
Owen Thomas, 18’781
L
imitation of mouth opening related to a developmental aberration of the coronoid process is uncommon. Unilateral hyperplasia and osteochondromatous change of the coronoid process have been reported sporadically. If one can estimate from the literature, however, bilateral hyperplasia is rare, only six cases being reported to date.2-6 Rowe,5 in describing two cases, has left little to be added by other authors, and repetition of much detail in this article is not justified. All of the above authors, with the exception of Lyon and Sarnat! and Rowe,5 use an extraoral approach to the coronoid process, either by a horizontal incision in the vicinity of the zygomatic arch or by a submandibular incision. Van Zile and Johnson2 and Mohnac4 operate on each side separately, with an interval of one week between procedures. Postoperative physiotherapy is sparsely covered by most authors, who nonspecifically mention deep diathermy, electrical stimulation, and functional exercises with “exercising appliances” applied 4 to 8 days postoperatively. In one of his eases Rowe5 maintained fixation for 6 weeks because of the additional condylar neck surgery required; mechanical exercises were then commenced. Schulte,7 in treating temporomandibular joint ankylosis, commences moderate mandibular exercises on the fifth postoperative day and ultrasonic deep heat therapy on the eighth day; the regime of jaw exercises is continued for 8 weeks. Postoperative physiotherapy is an all-important phase in the management of *Formerly Senior Lecturer in Oral Surgery, University Pennington Terrace, North Adelaide, South Australia.
184
of Adelaide.
Present
address:
79
Hilaterai!
Volume 29 Number 2
hyp~wplwia
of coronoid
process
105
these conditions with respect to its effect on (I) “healing” fibrosis at the site of bony resection, (2) pre-existing fibrosis in the muscles of mastication, and (3) pre-existing fibrosis in both temporomandibular joints. The following case of bilateral coronoid hyperplasia is of special interest because of the previous surgical approach to the temporomandibular joint, the marked restriction in opening the mouth, and the concomitant difficulty in gaining surgical access. An intraoral procedure \vi\s used, and intensive physiotherapy was given postoperatively. CASE REPORT A 27-year-old man was referred to me by an orthopedic surgeon. His chief complaints were (1) inability to open the mouth, (2) difficulty in mastication, (3) poor clarity of speech, and (4) inadequacy of dental care. Minor restriction of jaw movement was first noticed 9 years earlier, following routine restorative dental treatment. Jaw movement decreased noticeably in the ensuing 2 years. Seven years ago the patient consulted his general medical practitioner who, after trying ‘Llocal heat treatment,” referred him to an orthopedic surgeon. Six months later the orthopedic surgeon removed the meniscus of the right temporomandibular joint, but this procedure failed to increase jaw mobility. Then followed a period in which numerous radiographs were taken and efforts were made to open the jam with corkscrew appliances and mouth gags, with the patient in both conscious and unconscious states.
Fig. fully.
2. Photograph
of 27-year-old
man with
marked
overbite
and inability
to open mouth
186
Fitzpatrick
Fig. 1. Preoperative
Oral Surg. February, 1970
tomograms
of coronoid
processes.
Three years ago the dental practitioner had difficulty in examining the mouth. The condition had worsened in the past 12 months. Medical history revealed no anomaly. There was no history of local or systemic infections. There were no neurologic symptoms. Examination showed a virile, well-adjusted man who was eager to cooperate and be cured. A painter by occupation, he appeared to be devoid of any peculiar motor habit patterns. There was no facial deformity, muscle dysplasia, or apparent muscle tenderness. Opening of the mouth was by hinge movement of the joints only and was limited to 14 mm., of which 9 mm. was unfortunately occupied by the severe overbite, thus providing an incisal clearance of 5 mm. (Fig. 1). No deviation of the mandible occurred on mouth opening, and no lateral excursion was obtainable. Maximum opening was positive, and no extension could be gained by applying force. Radiographs
Right and left lateral tomograms (Fig. 2), occipitomental, and submentovertex films demonstrated symmetrical enlargement of both coronoid processes. There appeared to be bony contact with the zygomatic process of the maxilla and calcification of the temporal ligamentus attachment. “Straight” joint films did not provide additional information except to demonstrate the presence of a joint space and normal morphology of the condylar heads. Surgical
procedure
Following a blind intubation and administration of a relaxant, an attempt was made to open the mouth, with negative results. Adrenaline l/160,000 was heavily infiltrated on both sides of the ascending rami. Working with a headlight, an incision was made from the zygomatic process of the maxilla and along the anterior border of the coronoid process to the buccal sulcua opposite the lower first molar. The temporal muscle was stripped from the ramus by means of a curved periosteal elevator in the sigmoid notch area. The coronoid process was found to be firmly impacted against the zygomatic arch anterolaterally and in contact medially with the lateral wall of
Volume 29 Number 2
Bilateral
hyperplasia
of coronoid
FQ. 3. Pronounced outlines of coronoid process are seen with muscle inserting into bony depression on anterolateral aspect (arrow).
portion
process
of
187
temporali:<
the maxilla; a medial or anterior approach to the upper aspect of the coronoid was noi feasible. The coronoid process was sectioned from the lateral aspect with a surgical tapered fissure bur. Access was provided by a special concave blade retractor, its end bent into the sigmoid notch. To prevent loss of the sectioned process into the temporal fossa, and perhaps later reossification, a g inch twist drill in an Archimedian handpiece was inserted into the coronoid process from the face, passing beneath the zygomatic arch and above Stensen’s duct, the transverse facial artery, and the buccal branch of the facial nerve. An 0.5 mm. soft stainless steel wire was then passed by the same route but, because of limited space on the medial aspect, the wire could be secured only following sectioning of the process before the gross upward movement had occurred by traction of the remaining attac.hed temporalis fibers. A similar procedure was adopted on the opposite side, and an incisal opening of 22 mm. was achieved with a marked “tearing noise” in the masseter and medial pterygoid muscles. The temporal aspect of the zygomatic arch contained a digital fossa which accommodated a bulky musculotendinous portion of the temporalis whose upper and distal fibers inserted into a well-defined saucer-shaped depression (arrow) on the nnterolateral aspect of the coronoid process (Fig. 3). There was no false joint between the coronoid process and the zygomatic arch, as described by some previous writers. Primary closure of the oral wounds ensued, with insertion of a 24.hour polythene tube drain. On the sixth day sutures were removed, and the incisal opening was 12 mm.
Fibrous ankylosis of the right temporomandibular joint (the side of the previous meniscectomy) was preoperatively contemplated as a possible complication, and a second-stage operation on this joint was envisaged if encouraged postoperative movement failed.
188
Pitzpatrick
Fig. 4. Postoperative
Fig. 5. Comparative processes (dry specimens).
Oral Burg. February, 1970
mouth opening
radiographs
of 40 mm.
of
normal
ramus
and
one
of
enlarged
coronoid
Ten days postoperatively, a rigid routine of physiotherapy was commenced. This consisted of the following: 1. Passive stretching of the masticatory muscles by insertion of wooden tongue spatulas between the premolar teeth; the patient then added to the number by slipping, without great force, additional spatulas between those already held. This was done on each side four times daily, and the number was recorded on each occasion. I have found that forced opening with mouth gags, etc. tends to create muscle spasm. 2. Ultrasonic therapy to right and left joints and short-wave diathermy to all the masticatory muscles was given twice daily for 2 weeks and then daily for a further 2 weeks. Passive stretch exercises always started immediately after the heat treatment. Incisal opening at 2 weeks was 20 mm. and was achieved by hinge action only of the temporomandibular joints. Six months postoperatively an incisal opening of 31 mm. was recorded, thus giving a
Volume 29 Number 2
Bilateral
hyperplasia
of coronoid process
189
total opening of 40 mm. with moderate translatory movements of both condylar heads (Fig. 4). A 2-year follow-up has revealed no recurrence. Histopathologic study of tissue taken from one specimea did not reveal any striking ohange. Radiographs of the in vitro process (Fig. 5) helped to confirm this. There was a dense cortex surrounding a residual fibrous marrow. A small area of fibrocartilage on the anterior aspect of the process appeared to be related to the bulky muscle attachment already mentioned and not to an area of “direct” contact with the zygomatic arch, as mentioned by Lyon and Sarnat6; it may be still considered to be mainly the response of bone to pressure, as proposed by Weinmann and Sicher.8
COMMENT
Long-term immobility of the mandible, whatever the cause, must be associate(l with some degree of disuse atrophy and fibrosis of the masticatory muscles. With immobility of the temporomandibular joint, the lateral pterygoid muscle would be the first to be fully affected; in addition, some degree of fibrosis of the synovial apparatus may be anti4pated.l Postoperative physiotherapy, to be effective, requires an intelligent and COoperative patient who has been informed of the anatomic and physiologic components of the proposed rehabilitation. The etiology of bilateral coronoid hyperplasia must, for the present, bc considered idiopathic. A possible pathogenesis may be the persistence of the growth center in the process beyond the prenatal period. If this were so, however, it might be reasonable to expect a greater incidence, and it is puzzling to find no casesrecorded before 1957. The ages of the patients described by various authors range from 14 to 27 years. It may well be that the onset of symptoms is delayed until the final en. croachment of the coronoid into the available infratemporal space, by which time the growth po’tential has been exhausted and a fairly normal histologic picture prevails. Peculiarities in the habits of muscular movement have not been clinically shown to be a convincing causative factor in the casesreviewed, although Sarnat and EngeJg Washburnlo and AvisI have shown experimentally that an overfunctioning muscle is capable of enlarging its attached bony process. Differentiation is made between the idiopathic coronoid enlargement and the osteochondromatous change ; the latter occurs in a similar age group (10 to 25 years) but is usually found to bc unilateral and is ‘?nushroom” shaped.12*l3 REFERENCES
1. Thomas, Hugh Owen: A Review of the Past and Present Treatment of Disease in the Hip, Knee and Ankle Joints, Liverpool, 1878, T. Dobb & Co., Publisher, p. 34-35. 2. Van Zile, W. N., and Johnson, W. B.: Bilateral Coronoid Process Exostoses Simulating Partial Ankylosis of the Temporomandibular Joint, J. Oral. Surg. 16: 72-77, 1957. 3. Shira, R. B., and Lister, R. C.: Limited Mandibular Movements Due to Enlargement of the Coronoid Process, J. Oral Surg. 16: 183-191, 1958. 4. Mohnae, A. M. : Bilateral Coronoid Osteochondromas, J. Oral Surg. 20: 506596, 1962. 5. Rowe, N. L.: Bilateral Developmental Hyperplasia of the Mandibular Coronoid Process, Brit. J. Oral Surg. 1: 90-104, 1963. 6. Lyon, L. Z., and Sarnat, B. G.: Limited Opening of the Mouth Caused by Enlarged Coronoid Processes, J. Amer. Dent. Ass. 67: 644-650, 1963. 7. Schulte, W. C.: Ankylosis of the Temporomandibular Joint, ORAL SURG. 24: 270-283> 1967. 8. Weiumann, J. P., and Sicher, H.: Bone and Bones, ed. 2, St. Louis, 1955, The C. V. Mosby Company.
190
Oral Surg. February, 1970
Fitzpatrick
9. Sarnat, B. G., and Engel, M. B.: A Serial Study of Mandibular of the Condyle in the &xacu rhesus Monkey, Plast. Reoonstr. 10. Washburn, 8. L.: Relation of the Temporal Muscle to Form 239-248, 1947. 11. Avis, V.: The Relation of the Temporal Muscle to the Form Amer. J. Phys. Anthrop. 17: 99-104, 1959. 12. Bra&ford, J. F.: An Unusual Osteochondroma From the Mandible, Brit. J. Radid. 25: 555556, 1952. 13. Shackelford, R. T., and Brown, W. H.: Restricted Jaw Motion of the Coronoid Process, J. Bone Joint Surg. 31A: 107-114, 1949.
Growth After Removal Burg. 7: 364-379, 1951. of Skull, Anat. sec. 99: of the Coronoid Coronoid
Process
Process, of
the
Due to Osteochondroma
surgery
is
(W.A.),
there
to
P.D.S.R.C.S.
be
found
proof
(Ens.),”
that
Test
can
anchylose
....
The Fakirs of India as they have no desire
have joints, which. are to
use
them,
the joints
stiff
from
remain
stiff
prolonged
d&se,
and as
. . . .
-Hugh
Owen Thomas, 18’781
L
imitation of mouth opening related to a developmental aberration of the coronoid process is uncommon. Unilateral hyperplasia and osteochondromatous change of the coronoid process have been reported sporadically. If one can estimate from the literature, however, bilateral hyperplasia is rare, only six cases being reported to date.2-6 Rowe,5 in describing two cases, has left little to be added by other authors, and repetition of much detail in this article is not justified. All of the above authors, with the exception of Lyon and Sarnat! and Rowe,5 use an extraoral approach to the coronoid process, either by a horizontal incision in the vicinity of the zygomatic arch or by a submandibular incision. Van Zile and Johnson2 and Mohnac4 operate on each side separately, with an interval of one week between procedures. Postoperative physiotherapy is sparsely covered by most authors, who nonspecifically mention deep diathermy, electrical stimulation, and functional exercises with “exercising appliances” applied 4 to 8 days postoperatively. In one of his eases Rowe5 maintained fixation for 6 weeks because of the additional condylar neck surgery required; mechanical exercises were then commenced. Schulte,7 in treating temporomandibular joint ankylosis, commences moderate mandibular exercises on the fifth postoperative day and ultrasonic deep heat therapy on the eighth day; the regime of jaw exercises is continued for 8 weeks. Postoperative physiotherapy is an all-important phase in the management of *Formerly Senior Lecturer in Oral Surgery, University Pennington Terrace, North Adelaide, South Australia.
184
of Adelaide.
Present
address:
79
Hilaterai!
Volume 29 Number 2
hyp~wplwia
of coronoid
process
105
these conditions with respect to its effect on (I) “healing” fibrosis at the site of bony resection, (2) pre-existing fibrosis in the muscles of mastication, and (3) pre-existing fibrosis in both temporomandibular joints. The following case of bilateral coronoid hyperplasia is of special interest because of the previous surgical approach to the temporomandibular joint, the marked restriction in opening the mouth, and the concomitant difficulty in gaining surgical access. An intraoral procedure \vi\s used, and intensive physiotherapy was given postoperatively. CASE REPORT A 27-year-old man was referred to me by an orthopedic surgeon. His chief complaints were (1) inability to open the mouth, (2) difficulty in mastication, (3) poor clarity of speech, and (4) inadequacy of dental care. Minor restriction of jaw movement was first noticed 9 years earlier, following routine restorative dental treatment. Jaw movement decreased noticeably in the ensuing 2 years. Seven years ago the patient consulted his general medical practitioner who, after trying ‘Llocal heat treatment,” referred him to an orthopedic surgeon. Six months later the orthopedic surgeon removed the meniscus of the right temporomandibular joint, but this procedure failed to increase jaw mobility. Then followed a period in which numerous radiographs were taken and efforts were made to open the jam with corkscrew appliances and mouth gags, with the patient in both conscious and unconscious states.
Fig. fully.
2. Photograph
of 27-year-old
man with
marked
overbite
and inability
to open mouth
186
Fitzpatrick
Fig. 1. Preoperative
Oral Surg. February, 1970
tomograms
of coronoid
processes.
Three years ago the dental practitioner had difficulty in examining the mouth. The condition had worsened in the past 12 months. Medical history revealed no anomaly. There was no history of local or systemic infections. There were no neurologic symptoms. Examination showed a virile, well-adjusted man who was eager to cooperate and be cured. A painter by occupation, he appeared to be devoid of any peculiar motor habit patterns. There was no facial deformity, muscle dysplasia, or apparent muscle tenderness. Opening of the mouth was by hinge movement of the joints only and was limited to 14 mm., of which 9 mm. was unfortunately occupied by the severe overbite, thus providing an incisal clearance of 5 mm. (Fig. 1). No deviation of the mandible occurred on mouth opening, and no lateral excursion was obtainable. Maximum opening was positive, and no extension could be gained by applying force. Radiographs
Right and left lateral tomograms (Fig. 2), occipitomental, and submentovertex films demonstrated symmetrical enlargement of both coronoid processes. There appeared to be bony contact with the zygomatic process of the maxilla and calcification of the temporal ligamentus attachment. “Straight” joint films did not provide additional information except to demonstrate the presence of a joint space and normal morphology of the condylar heads. Surgical
procedure
Following a blind intubation and administration of a relaxant, an attempt was made to open the mouth, with negative results. Adrenaline l/160,000 was heavily infiltrated on both sides of the ascending rami. Working with a headlight, an incision was made from the zygomatic process of the maxilla and along the anterior border of the coronoid process to the buccal sulcua opposite the lower first molar. The temporal muscle was stripped from the ramus by means of a curved periosteal elevator in the sigmoid notch area. The coronoid process was found to be firmly impacted against the zygomatic arch anterolaterally and in contact medially with the lateral wall of
Volume 29 Number 2
Bilateral
hyperplasia
of coronoid
FQ. 3. Pronounced outlines of coronoid process are seen with muscle inserting into bony depression on anterolateral aspect (arrow).
portion
process
of
187
temporali:<
the maxilla; a medial or anterior approach to the upper aspect of the coronoid was noi feasible. The coronoid process was sectioned from the lateral aspect with a surgical tapered fissure bur. Access was provided by a special concave blade retractor, its end bent into the sigmoid notch. To prevent loss of the sectioned process into the temporal fossa, and perhaps later reossification, a g inch twist drill in an Archimedian handpiece was inserted into the coronoid process from the face, passing beneath the zygomatic arch and above Stensen’s duct, the transverse facial artery, and the buccal branch of the facial nerve. An 0.5 mm. soft stainless steel wire was then passed by the same route but, because of limited space on the medial aspect, the wire could be secured only following sectioning of the process before the gross upward movement had occurred by traction of the remaining attac.hed temporalis fibers. A similar procedure was adopted on the opposite side, and an incisal opening of 22 mm. was achieved with a marked “tearing noise” in the masseter and medial pterygoid muscles. The temporal aspect of the zygomatic arch contained a digital fossa which accommodated a bulky musculotendinous portion of the temporalis whose upper and distal fibers inserted into a well-defined saucer-shaped depression (arrow) on the nnterolateral aspect of the coronoid process (Fig. 3). There was no false joint between the coronoid process and the zygomatic arch, as described by some previous writers. Primary closure of the oral wounds ensued, with insertion of a 24.hour polythene tube drain. On the sixth day sutures were removed, and the incisal opening was 12 mm.
Fibrous ankylosis of the right temporomandibular joint (the side of the previous meniscectomy) was preoperatively contemplated as a possible complication, and a second-stage operation on this joint was envisaged if encouraged postoperative movement failed.
188
Pitzpatrick
Fig. 4. Postoperative
Fig. 5. Comparative processes (dry specimens).
Oral Burg. February, 1970
mouth opening
radiographs
of 40 mm.
of
normal
ramus
and
one
of
enlarged
coronoid
Ten days postoperatively, a rigid routine of physiotherapy was commenced. This consisted of the following: 1. Passive stretching of the masticatory muscles by insertion of wooden tongue spatulas between the premolar teeth; the patient then added to the number by slipping, without great force, additional spatulas between those already held. This was done on each side four times daily, and the number was recorded on each occasion. I have found that forced opening with mouth gags, etc. tends to create muscle spasm. 2. Ultrasonic therapy to right and left joints and short-wave diathermy to all the masticatory muscles was given twice daily for 2 weeks and then daily for a further 2 weeks. Passive stretch exercises always started immediately after the heat treatment. Incisal opening at 2 weeks was 20 mm. and was achieved by hinge action only of the temporomandibular joints. Six months postoperatively an incisal opening of 31 mm. was recorded, thus giving a
Volume 29 Number 2
Bilateral
hyperplasia
of coronoid process
189
total opening of 40 mm. with moderate translatory movements of both condylar heads (Fig. 4). A 2-year follow-up has revealed no recurrence. Histopathologic study of tissue taken from one specimea did not reveal any striking ohange. Radiographs of the in vitro process (Fig. 5) helped to confirm this. There was a dense cortex surrounding a residual fibrous marrow. A small area of fibrocartilage on the anterior aspect of the process appeared to be related to the bulky muscle attachment already mentioned and not to an area of “direct” contact with the zygomatic arch, as mentioned by Lyon and Sarnat6; it may be still considered to be mainly the response of bone to pressure, as proposed by Weinmann and Sicher.8
COMMENT
Long-term immobility of the mandible, whatever the cause, must be associate(l with some degree of disuse atrophy and fibrosis of the masticatory muscles. With immobility of the temporomandibular joint, the lateral pterygoid muscle would be the first to be fully affected; in addition, some degree of fibrosis of the synovial apparatus may be anti4pated.l Postoperative physiotherapy, to be effective, requires an intelligent and COoperative patient who has been informed of the anatomic and physiologic components of the proposed rehabilitation. The etiology of bilateral coronoid hyperplasia must, for the present, bc considered idiopathic. A possible pathogenesis may be the persistence of the growth center in the process beyond the prenatal period. If this were so, however, it might be reasonable to expect a greater incidence, and it is puzzling to find no casesrecorded before 1957. The ages of the patients described by various authors range from 14 to 27 years. It may well be that the onset of symptoms is delayed until the final en. croachment of the coronoid into the available infratemporal space, by which time the growth po’tential has been exhausted and a fairly normal histologic picture prevails. Peculiarities in the habits of muscular movement have not been clinically shown to be a convincing causative factor in the casesreviewed, although Sarnat and EngeJg Washburnlo and AvisI have shown experimentally that an overfunctioning muscle is capable of enlarging its attached bony process. Differentiation is made between the idiopathic coronoid enlargement and the osteochondromatous change ; the latter occurs in a similar age group (10 to 25 years) but is usually found to bc unilateral and is ‘?nushroom” shaped.12*l3 REFERENCES
1. Thomas, Hugh Owen: A Review of the Past and Present Treatment of Disease in the Hip, Knee and Ankle Joints, Liverpool, 1878, T. Dobb & Co., Publisher, p. 34-35. 2. Van Zile, W. N., and Johnson, W. B.: Bilateral Coronoid Process Exostoses Simulating Partial Ankylosis of the Temporomandibular Joint, J. Oral. Surg. 16: 72-77, 1957. 3. Shira, R. B., and Lister, R. C.: Limited Mandibular Movements Due to Enlargement of the Coronoid Process, J. Oral Surg. 16: 183-191, 1958. 4. Mohnae, A. M. : Bilateral Coronoid Osteochondromas, J. Oral Surg. 20: 506596, 1962. 5. Rowe, N. L.: Bilateral Developmental Hyperplasia of the Mandibular Coronoid Process, Brit. J. Oral Surg. 1: 90-104, 1963. 6. Lyon, L. Z., and Sarnat, B. G.: Limited Opening of the Mouth Caused by Enlarged Coronoid Processes, J. Amer. Dent. Ass. 67: 644-650, 1963. 7. Schulte, W. C.: Ankylosis of the Temporomandibular Joint, ORAL SURG. 24: 270-283> 1967. 8. Weiumann, J. P., and Sicher, H.: Bone and Bones, ed. 2, St. Louis, 1955, The C. V. Mosby Company.
190
Oral Surg. February, 1970
Fitzpatrick
9. Sarnat, B. G., and Engel, M. B.: A Serial Study of Mandibular of the Condyle in the &xacu rhesus Monkey, Plast. Reoonstr. 10. Washburn, 8. L.: Relation of the Temporal Muscle to Form 239-248, 1947. 11. Avis, V.: The Relation of the Temporal Muscle to the Form Amer. J. Phys. Anthrop. 17: 99-104, 1959. 12. Bra&ford, J. F.: An Unusual Osteochondroma From the Mandible, Brit. J. Radid. 25: 555556, 1952. 13. Shackelford, R. T., and Brown, W. H.: Restricted Jaw Motion of the Coronoid Process, J. Bone Joint Surg. 31A: 107-114, 1949.
Growth After Removal Burg. 7: 364-379, 1951. of Skull, Anat. sec. 99: of the Coronoid Coronoid
Process
Process, of
the
Due to Osteochondroma