Neuroradiologv
Neuroradiology 17, 121-125 (1979)
@ by Springer-Verlag 1979
Congenital Absence of a Pedicle in the Cervical Spine: A New Approach with CT Scan E. Brugman, Y. Palmers and B. Staelens Department of Radiology, University Hospital K. U. Leuven, Belgium
Summary. After complete review of the literature concerning the congenital absent pedicle syndrome, another typical case is presented. In the opinion of the authors, the diagnostic importance of the associated clinical symptoms is doubtful. Furthermore they demonstrate the great value of CT in the differential diagnosis of this lesion. Key words: Cervical vertebrae - Congenital anomaly - Absent pedicle
Introduction The discovery of an enlarged intervertebral foramen during a roentgenological examination may not be indicative of a dumb-bell spinal tumor, and may be unrelated to the patient's complaints. Fifteen cases have been reported in which an enlarged intervertebral foramen was the result of a congenital absence of a cervical vertebral pedicle. There was no relation to sex or age. It is our purpose to report another case and to consider the roentgenographic features which distinguish it from enlarged foramina due to other causes, and to evaluate the relation between the malformation and the complaints due to it. Finally, we want to demonstrate the use of computed tomography in the cervical spinal region.
the other two patients, the lesion was due to destructive bone changes caused by a tortuous vertebral artery. Steinbach et al. [10] observed the absence of the right T7 pedicle incidentally during an examination for a swallowed foreign body. Surgical exploration did not disclose the expected spinal tumor, but an enlarged foramen and an abnormal dural pouch, including both C 7 and C8 nerve roots, which was also confirmed by subsequent myelography. Buetti [2] reported the absence of the left pedicle of C 5 found during studies in a patient suspected of a tumor of the posterior fossa. The patient complained of a stiff neck on flexion. Grasser and Klein [5] and Abel [1] each reported a patient who had no clinical symptoms. The anomaly in both cases was on the left at C 5 and C 6 respectively and was found during examination following injury to the neck.
1
Review of Previously Reported Cases Hadley [7] published three cases, one of which was a typical example of congenital absence of the left C s pedicle, discovered incidentally following trauma. In
Fig. I. The Absent Pedicle Syndrome. 1 Absent pedicle; 2 Abnormal transverse process; 3 Displaced articular segment (abnormality of lateral mass) 0028-3940/7 9/0017/0121/$01.00
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Figs. 2 and 3. Standard AP and left oblique X-rays show absence of left pedicle of C 7. Articular mass of C 7 displaced dorsally relative to articular facets of C6 and T 1
Zatz et al. [12] observed two cases. One patient had symptoms suggesting a cervical cord lesion. The right pedicle of C6 was absent. Their second patient was investigated following a neck injury and had no complaints before. The left pedicle was absent at C5. Gaizler and Gaizler [6] described a patient who had paresthesia in an arm for 1 year, and found C5 was absent on the left. Wilson et al. [11] reported two cases. The first had pain in the neck for 3 years, numbness in the right upper extremity and difficulty in writing. C4 was absent on the right. The second one had no clinical symptoms. He was investigated after a car accident, and C6 was absent on the left. Louyot et al. [8] reported a case with absence of the right pedicle at C6 with a C7 radicular syndrome, associated with a herniated disc, Oestreich et al. [9] reported a child with pain in the neck, scapula, and arm, and difficulty in writing, in whom the right pedicle was absent at C4. Danziger et al. [4] described two cases involving C6, one on the right, the other on the left. Both had headaches, and pain and numbness in the arm. In the case of Chapman the left pedicle was absent at C6. The patient had pain in the right (!) arm for 3 years.
Case Report A woman, aged 29 years, had various complaints for many years, mostly of the neurovegetative type, especially of dyspepsia and atypical gastric discomfort. Roentgenograms of the entire spine were performed psychotherapeutically rather than for any specific indication. The standard roentgenograms revealed a bone defect in the region of the left pedicle of C7.
Roentgenographic features Frontal, lateral, 45 ° oblique anterior radiographs and tomographs revealed the following characteristic features (Figs. 2 and 3): 1. Complete absence of the pedicle of C7 on the left side. The superjacent and subjacent pedicles have a normal shape. 2. The intervertebral foramen is elongated in the axis of the spine and the dorsoventral diameter is slightly increased as a result of the dorsal displacement of the lateral mass. Notice the intact cortical delineation of the lesion which makes no neoformative process obvious.
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Fig. 4. Absence of left pedicle of C 7 is evident. Spot image 3 illustrates intact cortical delineation of normal insertion place of missing pedicle
Fig. 5. Dorsal displacement of left lateral mass
3. The lateral mass is malformed and is in a more dorsal position than the line formed by the lateral masses of the other vertebrae. 4. Displaced articular segment. The superior articular facet is absent and the superior tip of the malformed lateral mass is in a position dorsal to the inferior articular facet of the superjacent vertebra. The inferior articular facet is consequently even more dorsal to the superior one of the subjacent vertebra. This can be described as a disturbance of the normal canine tooth-like appearance of the vertical chain of articulations. 5. The transverse process is smaller and partially deficient in its dorsal portion. The contralateral structures of the affected vertebra are strictly normal.
CT Findings CT of the lower cervical region revealed a beautiful transverse anatomical image of the lesion. (Figs. 4, 5, and 6). One notes in the region of C7: 1. The absence of the left pedicle (Fig. 4). 2. The malformation and dorsal displacement of the lateral mass (Fig. 5). For comparison, see the normal relationship of these structures at the C 6 level of the same patient (Fig. 6). 3. The abnormal transverse process (Figs. 4 and 5). 4. The intact cortical delineation of the normal insertion place of the missing pedicle. (cf. inset image, produced with a higher window width). 5. During the same session, densitometry of the dif-
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E. Brugman et al.: Congenital Absence of Pedicle in Cervical Spine
Fig. 6. Normal cervical structures at level of
feren structures excluded most of the other possible differential hypotheses so that the exact origin of the lesion could be proven. The differential diagnosis should include: 1. Tumor: (a) primary or metastatic malignant tumor; (b) dumb-bell spinal tumor (e.g., neurofibroma). 2. Tortuous vertebral artery. 3. Traumatic fracture of a pedicle. 4. Spondylitis infectiosa or local osteitis. The CT findings can help us to differentiate between the several possibilities in this case. Critical densitometrical study of the soft tissues at the level of the missing left pedicle of C7 allows us to exclude a tumor; moreover there is no morphological evidence of an abnormal soft tissue mass. The CT images made after contrast enhancement do not reveal any alteration of the picture, so a vascular anomaly such as a tortuous vertebral artery is unlikely. Furthermore, the sharp cortical delineation at the borders surrounding the bony defect (which is very well visualized by changing the window width and the window height) makes a traumatic fracture or an inflammatory bone lesion as well as a malignant bone erosion quite unlikely.
Discussion
There have been many discussions in the past whether or not a congenitally absent pedicle is an asymptomatic roentgenographic curiosity. Some authors placed much importance on the clinical symptoms, which would be caused by instability of
C6
the spine at the segment involved and subsequent soft tissue injuries. However, from the 15 cases reported, at least 7 had no obvious neurological symptoms due to the lesion, and the anomaly was found incidentally as was the case in our patient. Some had symptoms of pain following a neck injury, but no complaints before. In other cases, the symptoms were probably caused by cervical arthrosis. We do however agree that the anomaly can cause some instability and can predispose to greater vulnerability in case of trauma. In our opinion, the clinical symptoms are of minor importance, and are certainly not specific for the diagnosis. However, because of the apparently congenital origin of the deformity, the physician should consider this possibility whenever dealing with a patient, especially a child, who has symptoms referring to the cervical spine. References 1. Abel, M.S.: Moderately severe whiplash injuries of cervical spine and their roentgenologic diagnosis. Clin. Orthop. 12, 189-208 (1958) 2. Buetti, C.: Zur RSntgendiagnostik seltener Fehlbildungen der Halswirbels~iule. Radiol. Clin. 22, 141 (1953) 3. Chapman, M.: Congenital absence of a pedicle in a cervical vertebra (C6). Skeletal Radiol. 1, 65-66 (1976) 4. Danziger, J., Jackson, H., Bloch, S.: Congenital absence of a pedicle in the cervical vertebra. Clin. Radiol. 26, 53-60 (1975) 5. Grasser, H., Klein, E.: Differentialdiagnose seltener Wirbels~iulenver~inderungen. Zeitschr. Orthop. 88, 550-553 (1957) 6. Gaizler, Sr., G., Gaizler, Jr., G.: Fehler einer Bogenwurzel an der Halswirbelsfiule. Fortschr. Geb. R6ntgenstr. Nuklearmed. 99, 421-423 (1963)
E. Brugman et al.: Congenital Absence of Pedicle in Cervical Spine
125
7. Hadley, L.A.: Congenital absence of pedicle from cervical vertebra. Am. J. Roentgenol. Rad. Ther. Nucl. Med. 55, 193-197 (1946) 8. Louyot, P., Gaucher, A., Laxenaire, M., Combebias, J.F.: Ag6ndsie du pddicule droit de la sixi~me vert~bre cervicale et syndrome radiculaire C7 par hernie discale. Rev. Rhumatisme 34, 276-279 (1967) 9. Oestreich, A.E., Young, L.W.: The absent cervical pedicle syndrome: a case in childhood. Am. J. Roentgenol. 107, 505-510 (1969) 10. Steinbach, H. C., Boldrey, E. B., Sody, F. A.: Congenital absence of a pedicle and superior facet from a cervical vertebra. Radiology 59, 838-840 (1952) 11. Wilson, C. B., Norrell, H. A. Jr.: Fehler einer Bogenwurzel an
der Halswirbels~iule. Fortschr. Geb. R6ntgenstr. Nuklearmed. 99, 421-423 (1963) 12. Zatz, L. M., Burgess, D. W., Hanbery, J. W.: Agenesis of pedicle in cervical spine. J. Neurosurg. 20, 564-596 (1963)
Received: 31 October 1978
Dr. E. Brugman Department of Radiology University Hospital B-3000 Leuven Belgium
Neuroradiology 17, 121-125 (1979)
@ by Springer-Verlag 1979
Congenital Absence of a Pedicle in the Cervical Spine: A New Approach with CT Scan E. Brugman, Y. Palmers and B. Staelens Department of Radiology, University Hospital K. U. Leuven, Belgium
Summary. After complete review of the literature concerning the congenital absent pedicle syndrome, another typical case is presented. In the opinion of the authors, the diagnostic importance of the associated clinical symptoms is doubtful. Furthermore they demonstrate the great value of CT in the differential diagnosis of this lesion. Key words: Cervical vertebrae - Congenital anomaly - Absent pedicle
Introduction The discovery of an enlarged intervertebral foramen during a roentgenological examination may not be indicative of a dumb-bell spinal tumor, and may be unrelated to the patient's complaints. Fifteen cases have been reported in which an enlarged intervertebral foramen was the result of a congenital absence of a cervical vertebral pedicle. There was no relation to sex or age. It is our purpose to report another case and to consider the roentgenographic features which distinguish it from enlarged foramina due to other causes, and to evaluate the relation between the malformation and the complaints due to it. Finally, we want to demonstrate the use of computed tomography in the cervical spinal region.
the other two patients, the lesion was due to destructive bone changes caused by a tortuous vertebral artery. Steinbach et al. [10] observed the absence of the right T7 pedicle incidentally during an examination for a swallowed foreign body. Surgical exploration did not disclose the expected spinal tumor, but an enlarged foramen and an abnormal dural pouch, including both C 7 and C8 nerve roots, which was also confirmed by subsequent myelography. Buetti [2] reported the absence of the left pedicle of C 5 found during studies in a patient suspected of a tumor of the posterior fossa. The patient complained of a stiff neck on flexion. Grasser and Klein [5] and Abel [1] each reported a patient who had no clinical symptoms. The anomaly in both cases was on the left at C 5 and C 6 respectively and was found during examination following injury to the neck.
1
Review of Previously Reported Cases Hadley [7] published three cases, one of which was a typical example of congenital absence of the left C s pedicle, discovered incidentally following trauma. In
Fig. I. The Absent Pedicle Syndrome. 1 Absent pedicle; 2 Abnormal transverse process; 3 Displaced articular segment (abnormality of lateral mass) 0028-3940/7 9/0017/0121/$01.00
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E. Brugman et al.: Congenital Absence of Pedicle in Cervical Spine
Figs. 2 and 3. Standard AP and left oblique X-rays show absence of left pedicle of C 7. Articular mass of C 7 displaced dorsally relative to articular facets of C6 and T 1
Zatz et al. [12] observed two cases. One patient had symptoms suggesting a cervical cord lesion. The right pedicle of C6 was absent. Their second patient was investigated following a neck injury and had no complaints before. The left pedicle was absent at C5. Gaizler and Gaizler [6] described a patient who had paresthesia in an arm for 1 year, and found C5 was absent on the left. Wilson et al. [11] reported two cases. The first had pain in the neck for 3 years, numbness in the right upper extremity and difficulty in writing. C4 was absent on the right. The second one had no clinical symptoms. He was investigated after a car accident, and C6 was absent on the left. Louyot et al. [8] reported a case with absence of the right pedicle at C6 with a C7 radicular syndrome, associated with a herniated disc, Oestreich et al. [9] reported a child with pain in the neck, scapula, and arm, and difficulty in writing, in whom the right pedicle was absent at C4. Danziger et al. [4] described two cases involving C6, one on the right, the other on the left. Both had headaches, and pain and numbness in the arm. In the case of Chapman the left pedicle was absent at C6. The patient had pain in the right (!) arm for 3 years.
Case Report A woman, aged 29 years, had various complaints for many years, mostly of the neurovegetative type, especially of dyspepsia and atypical gastric discomfort. Roentgenograms of the entire spine were performed psychotherapeutically rather than for any specific indication. The standard roentgenograms revealed a bone defect in the region of the left pedicle of C7.
Roentgenographic features Frontal, lateral, 45 ° oblique anterior radiographs and tomographs revealed the following characteristic features (Figs. 2 and 3): 1. Complete absence of the pedicle of C7 on the left side. The superjacent and subjacent pedicles have a normal shape. 2. The intervertebral foramen is elongated in the axis of the spine and the dorsoventral diameter is slightly increased as a result of the dorsal displacement of the lateral mass. Notice the intact cortical delineation of the lesion which makes no neoformative process obvious.
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Fig. 4. Absence of left pedicle of C 7 is evident. Spot image 3 illustrates intact cortical delineation of normal insertion place of missing pedicle
Fig. 5. Dorsal displacement of left lateral mass
3. The lateral mass is malformed and is in a more dorsal position than the line formed by the lateral masses of the other vertebrae. 4. Displaced articular segment. The superior articular facet is absent and the superior tip of the malformed lateral mass is in a position dorsal to the inferior articular facet of the superjacent vertebra. The inferior articular facet is consequently even more dorsal to the superior one of the subjacent vertebra. This can be described as a disturbance of the normal canine tooth-like appearance of the vertical chain of articulations. 5. The transverse process is smaller and partially deficient in its dorsal portion. The contralateral structures of the affected vertebra are strictly normal.
CT Findings CT of the lower cervical region revealed a beautiful transverse anatomical image of the lesion. (Figs. 4, 5, and 6). One notes in the region of C7: 1. The absence of the left pedicle (Fig. 4). 2. The malformation and dorsal displacement of the lateral mass (Fig. 5). For comparison, see the normal relationship of these structures at the C 6 level of the same patient (Fig. 6). 3. The abnormal transverse process (Figs. 4 and 5). 4. The intact cortical delineation of the normal insertion place of the missing pedicle. (cf. inset image, produced with a higher window width). 5. During the same session, densitometry of the dif-
124
E. Brugman et al.: Congenital Absence of Pedicle in Cervical Spine
Fig. 6. Normal cervical structures at level of
feren structures excluded most of the other possible differential hypotheses so that the exact origin of the lesion could be proven. The differential diagnosis should include: 1. Tumor: (a) primary or metastatic malignant tumor; (b) dumb-bell spinal tumor (e.g., neurofibroma). 2. Tortuous vertebral artery. 3. Traumatic fracture of a pedicle. 4. Spondylitis infectiosa or local osteitis. The CT findings can help us to differentiate between the several possibilities in this case. Critical densitometrical study of the soft tissues at the level of the missing left pedicle of C7 allows us to exclude a tumor; moreover there is no morphological evidence of an abnormal soft tissue mass. The CT images made after contrast enhancement do not reveal any alteration of the picture, so a vascular anomaly such as a tortuous vertebral artery is unlikely. Furthermore, the sharp cortical delineation at the borders surrounding the bony defect (which is very well visualized by changing the window width and the window height) makes a traumatic fracture or an inflammatory bone lesion as well as a malignant bone erosion quite unlikely.
Discussion
There have been many discussions in the past whether or not a congenitally absent pedicle is an asymptomatic roentgenographic curiosity. Some authors placed much importance on the clinical symptoms, which would be caused by instability of
C6
the spine at the segment involved and subsequent soft tissue injuries. However, from the 15 cases reported, at least 7 had no obvious neurological symptoms due to the lesion, and the anomaly was found incidentally as was the case in our patient. Some had symptoms of pain following a neck injury, but no complaints before. In other cases, the symptoms were probably caused by cervical arthrosis. We do however agree that the anomaly can cause some instability and can predispose to greater vulnerability in case of trauma. In our opinion, the clinical symptoms are of minor importance, and are certainly not specific for the diagnosis. However, because of the apparently congenital origin of the deformity, the physician should consider this possibility whenever dealing with a patient, especially a child, who has symptoms referring to the cervical spine. References 1. Abel, M.S.: Moderately severe whiplash injuries of cervical spine and their roentgenologic diagnosis. Clin. Orthop. 12, 189-208 (1958) 2. Buetti, C.: Zur RSntgendiagnostik seltener Fehlbildungen der Halswirbels~iule. Radiol. Clin. 22, 141 (1953) 3. Chapman, M.: Congenital absence of a pedicle in a cervical vertebra (C6). Skeletal Radiol. 1, 65-66 (1976) 4. Danziger, J., Jackson, H., Bloch, S.: Congenital absence of a pedicle in the cervical vertebra. Clin. Radiol. 26, 53-60 (1975) 5. Grasser, H., Klein, E.: Differentialdiagnose seltener Wirbels~iulenver~inderungen. Zeitschr. Orthop. 88, 550-553 (1957) 6. Gaizler, Sr., G., Gaizler, Jr., G.: Fehler einer Bogenwurzel an der Halswirbelsfiule. Fortschr. Geb. R6ntgenstr. Nuklearmed. 99, 421-423 (1963)
E. Brugman et al.: Congenital Absence of Pedicle in Cervical Spine
125
7. Hadley, L.A.: Congenital absence of pedicle from cervical vertebra. Am. J. Roentgenol. Rad. Ther. Nucl. Med. 55, 193-197 (1946) 8. Louyot, P., Gaucher, A., Laxenaire, M., Combebias, J.F.: Ag6ndsie du pddicule droit de la sixi~me vert~bre cervicale et syndrome radiculaire C7 par hernie discale. Rev. Rhumatisme 34, 276-279 (1967) 9. Oestreich, A.E., Young, L.W.: The absent cervical pedicle syndrome: a case in childhood. Am. J. Roentgenol. 107, 505-510 (1969) 10. Steinbach, H. C., Boldrey, E. B., Sody, F. A.: Congenital absence of a pedicle and superior facet from a cervical vertebra. Radiology 59, 838-840 (1952) 11. Wilson, C. B., Norrell, H. A. Jr.: Fehler einer Bogenwurzel an
der Halswirbels~iule. Fortschr. Geb. R6ntgenstr. Nuklearmed. 99, 421-423 (1963) 12. Zatz, L. M., Burgess, D. W., Hanbery, J. W.: Agenesis of pedicle in cervical spine. J. Neurosurg. 20, 564-596 (1963)
Received: 31 October 1978
Dr. E. Brugman Department of Radiology University Hospital B-3000 Leuven Belgium
