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Transethmoidal encephalomeningocele
Surg Neurol 1985;24:651-5
651
Transethmoidal Encephalomeningocele Takashi Hayashi, M.D., Hidetsuna
Utsunomiya,
M.D., and Takeo
Hashimoto,
M.D.
Departments of Neurosurgery, Neuroradiology, and Neonatology, St. Mary's Hospital, Kurume, Japan
Hayashi T, Utsunomiya H, Hashimoto T. Transethmoidal encephalomeningocele. Surg Neurol 1985;24:651-5.
A newborn child with a basal meningoencephalocele of the transethmoidal type is reported with an intranasal obstruction and hypertelorism as the principal abnormalities. This disease has been reported in the literature with various facial and central nervous system deformities and was considered as a type of median cranioencephalic dysraphia. Precise diagnosis of this disease seems extremely important for classification and has a direct bearing on the prognosis. KEY WORDS: Transethmoidal meningoencephalocele; Basal meningoencephalocele; Hypertelorism; Congenital hydrocephalus, infant
Transethmoidal meningoencephalocele is a protrusion of a part of the brain and meninges through an ethmoidal defect into the nasal cavity and is classified as a subtype of basal meningoencephalocele. This condition is extremely rare, but there have been a few cases reported [ 1,10]. Recently, we encountered a newborn child with this deformity. It was definitely diagnosed by neuroradiologic examinations. The main diagnostic points and their importance are described together with a discussion on embryology. Case Report A 1-day-old male was born by Caesarean section at full term with a body weight at birth of 3500 g, cranial circumference of 35.2 cm, and 5-minute Apgar score of 10. Facial abnormalities such as hypertelorism and deformed anterior nares were noted at birth. Because he was dyspneic during nursing, he was transferred to our clinic. Hypertelorism, unequal anterior nares, and micrograthia were noted as facial abnormalities at admis-
Address reprint requests to: Takashi Hayashi, M.D., Department of Neurosurgery, St. Mary's Hospital, 422 Tsubuku Honmachi, Kurume 830, Japan.
© 1985 by ElsevierSciencePublishing Co., Inc.
sion. Both nasal cavities were completely obstructed by abnormal bony tissue about 3 cm from the anterior border of the nares. Neurologically, no obvious abnormality was noted and the biochemical findings in the blood were normal.
Examinations In the anteroposterior view of the craniogram, a bony defect was noted in the base of the frontal skull. In the lateral view, the sella turcica was normal and the limbus sphenoidal was noted, but the frontoethmoidal suture could not be identified. In the coronal section of the tomograph, a bony defect was noted in the base o f the frontal skull with a maximum diameter of about 1.8 cm in the ethmoid bone. N o tumor density was apparent but no structure was noted in the nasal cavity (Figure 1). A computed tomography scan revealed an isodensity zone representing brain tissue in the transverse plane in the nasal cavity, as well as a deeply depressed frontal skull base. Both orbitas were separated, indicating hypertelorism. In addition, obvious enlargement o f the lateral ventricles was noted, suggesting congenital hydrocephalus. In the coronal and sagittal computed tomography scans, brain tissue was clearly seen to protrude into the nasal cavity (Figure 2). In a lateral arteriogram of the right internal carotid artery, the olfactory artery, distributed to the rectal gyrus and the olfactory groove, appeared to be situated lower than usual and extended downward running into the nasal cavity (Figure 3). In an arteriogram of the left internal carotid artery, nearly the same findings as on the right side were obtained. Bilateral pericallosal arteries were straightened and extended because of the hydrocephalus but no findings suggesting a defect of the corpus callosum were noted.
Operation Bifrontal craniotomy was performed with the patient in the supine position and ventricular drainage was carried out from the anterior horn of the right lateral ventricle. First, when the dura mater was gradually stripped from 0090-3019/85/$3.30
652
Surg Neurol 1985;24:651-5
Hayashi et al
Discussion
Figure 1. Frontal tomography of the skull shows defect of cribriform plate (arrowheads) and abnormal structures in the nasal cavity.
the inner table of the frontal skull base on both sides under a surgical microscope, the crista galli could not be seen, but the base of the frontal skull was found to be deeply depressed into the ethmoid sinus proper. At this site, the dura mater of the frontal skull base and the bottom of the frontal lobe were displaced inside the nasal cavity (Figure 4). The bottom of the depressed frontal skull base was composed of rough connective and cartilaginous tissues. The optic nerves on both sides appeared to enter the optic canal normally and be of normal color and size. However, the olfactory bulbs and tracts were absent on both sides. The dura mater was tightly sutured, the bony defect in the base of the frontal skull was closed with Lyodura and also with frontal bone, and Lyodura was applied to the reconstructed base of the skull to prevent liquorrhea. Repositioning of the meningoencephalocele and plastic surgery of the frontal skull base were completed. At a second-stage operation, plastic surgery of the nasal cavity is anticipated.
Basal meningoencephalocele is classified into four types depending on the site of the bony defect [12], i.e., the transethmoidal type where the rumor protrudes from the defect in the ethmoid bone into the nasal fossa; the sphenoethmoidal type where the bony defect is present between the sphenoid and ethmoid bones; the transsphenoidal type where the bony defect is present in the sphenoid bone, especially the sella turcica, and a tumor is seen in the epipharnyx; and the sphenoorbital type where the tumor protrudes from the superior orbital fissure into the orbit. In our present case, the transethmoidal type was diagnosed because the limbus sphenoidal was visualized radiologically, the ethmoid bone was nearly completely absent, and the crista galli was not found at operation. Bony defects of the transethmoidal type reported thus far are relatively small and often limited to the cribriform plate on one side [1], but the bony defect in our case was large and was found to involve nearly the entire ethmoid bone, a finding that may be said to be characteristic. In basal meningoencephalocele, the tumor, unlike those at other sites, is often not detectable from the outside. Gisselsson [6] mentioned the following as symptoms of basal meningoencephalocele: (a) intranasal rumor and obstruction from the time of birth, (b) pulsation of the rumor synchronous with the pulse or respiration, (c) complications of facial deformities such as hypertelorism, and (d) leakage ofcerebrospinal fluid from the nose, meningitis, etc. The characteristics of this disease are, in addition to an intranasal tumor, facial deformities such as hypertelorism, harelip, and cleft palate [6,7,10,11]. With these malformations, agenesis of the corpus callosum [10] and congenital hydrocephalus [5] may also be present. In our case, obstruction of the nasal cavity, hypertelorism, and congenital hydrocephalus were identified. Such congenital malformations indicate the origin of this disease in the embryonic stage and embryologic studies on the pathogenesis of this disease have been conducted by various workers. A representative study is the adhesive theory of Geoffery St. Hilliare et al [9], which states that in the embryonic period, disturbance appears in the separation of epidermal ectoblast and nervous system ectoblast, causing a disturbance in the development ofmesoblastic tissue, i.e., the bone. Other theories include Steinberg's theory of neural tube obstruction and disturbance [8], Spring's theory of ventricular pressure increase in the embryonal period [6], and Wiese's theory of disturbance in the development of bone [13], but none of these theories has been fully accepted. Complications by multiple deformities, mainly median fissures of the skull, face, and brain, suggest that this disease belongs to the series of median cranioencephalic dysraphia mentioned by de Morsier [3].
Transethmoidal Encephalomeningocele
Surg Neurol 1985;24:651-5
653
A
Figure 2. (A) Direct coronal and (B) sagittal computed tomography scans reveal meningoencephalocele at the ethmoidal region associated with congenital hydrocephalus. (C) Schematic drawing ol the transethmoidal encephalomeningocele in our case. M = maxilla~ bone: N = nasal bone: S = sphenoid bone.
Herniated brain
Figure 3. Lateral arteriogram of right internal carotid artery shows that the olfactory artery originatedfrom the proximal portion of anterior cerebral artery and herniated into the nasal cavity through the skull schesis.
654
Surg Neurol 1985;24:651-5
Figure 4. Operative photograph shows a wide deject of the frontal skull base in the interorbital region. Brain tissue covered with meninges was herniated into the nasal cavity through the bony defect.
The treatment is solely surgical and the first successful operation was performed by Fenger et al (1895) [4]. Richter et al in 1813 were the first to report a case o f this disease [6] but the interval up to the first surgical operation was 85 years. T h e reason for this is the fact that preoperative diagnosis could not be precisely performed and intracranial surgery was seldom undertaken. Because most cases were diagnosed erroneously as nasal polyps, the tumor was excised by intranasal manipulation, resulting in severe postoperative complications such as meningitis and even death. However, the rate of success has become very high since Dandy in 1929 [2] and Gisselsson in 1947 [6] began operating upon these malformations intracranially. The advantages o f intracranial operations include the fact that the operative procedure can be performed in a "clean" place compared with the intranasal operation, a wide field o f vision can be obtained, reposition of the hernia is easy, and the bony defect can be treated under watertight conditions. However, the most important point seems to be that the
Hayashi et al
operative method can be decided with a precise diagnosis, which also greatly influences the prognosis. In our case, reposition of the cranial dysraphia was performed by intracranial manipulation and the course has been good during the 3 postoperative months, with no sign of meningitis.
References I. Blumenfeld R, Skolnik EM. lntranasal encephaloceles. Arch Otolaryngol 1965;82:527-31. 2. Dandy WE. The operative treatment for certain cases of meningocele or encephalocele into the orbit. Arch Ophthalmol 1929;2:123-32. 3. De Morsier G. Median cranioencephalic dysraphia and olfactogenital dysplasia. World Neurol 1962;3:485-506. 4. Fenger C. Basal hernias of the brain. AmJ Med Sci 1895;109:1-17. 5. Gerlach J. Missbildungen des Gehirns und der Hirnhaute. Die Diencephalon. In: Olivecrona H, Tonnis W, eds. Handbuch der Neurochirurgie, IV/I. Berlin: Springer-Verlag, 1960:169-83. 6. Gisselsson L. lntranasal forms of encephalomeningocele. Acta Otolaryngol 1947;35:519-31. 7. Lewin ML, Shuster MM. Transpalatal correction of basilar meningocele with cleft palate. Arch Surg 1965;90:687-93. 8. Mood GF. Congenital anterior herniations of brain. Ann Otol Rhinol Laryngol 1938;47:391-401. 9. Pollock JA, Newton TH, Hoyt WF. Transsphenoidal and trans-
Transethmoidal Encephalomeningocele
ethmoidal cncephalomeningoceles: a review of clinical and roentgen features in 8 cases. Radiology 1968;90:442-53. 10. Sakoda K, Uozumi T, Hirakawa K, Harada Y, Chikuie S, Sakaki U, Ibuki Y. Sphenoethmoidal meningoencephalocele associated with agenesis of corpus callosum and median cleft lip and palate. Report of two cases. Brain Nerve (Tokyo) 1979;31:947-53. 11. Stuart EA. An otolaryngologic aspect of frontal meningocele. Arch Otolaryngol 1949;40:171-4.
Surg N e u r o l 1985;24:651-5
655
12. Suwanwela C, Suwanwela N. A morphological classification of sincipital encephalomeningoceles. J Neurosurg 1972;36:201- l l. 13. Wiese GM, Major MC, Ludwig GK, Colonel MC, William MM. Transsphenoidal meningohydroencephalocele. J Neurosurg 1972;36:475-8.
651
Transethmoidal Encephalomeningocele Takashi Hayashi, M.D., Hidetsuna
Utsunomiya,
M.D., and Takeo
Hashimoto,
M.D.
Departments of Neurosurgery, Neuroradiology, and Neonatology, St. Mary's Hospital, Kurume, Japan
Hayashi T, Utsunomiya H, Hashimoto T. Transethmoidal encephalomeningocele. Surg Neurol 1985;24:651-5.
A newborn child with a basal meningoencephalocele of the transethmoidal type is reported with an intranasal obstruction and hypertelorism as the principal abnormalities. This disease has been reported in the literature with various facial and central nervous system deformities and was considered as a type of median cranioencephalic dysraphia. Precise diagnosis of this disease seems extremely important for classification and has a direct bearing on the prognosis. KEY WORDS: Transethmoidal meningoencephalocele; Basal meningoencephalocele; Hypertelorism; Congenital hydrocephalus, infant
Transethmoidal meningoencephalocele is a protrusion of a part of the brain and meninges through an ethmoidal defect into the nasal cavity and is classified as a subtype of basal meningoencephalocele. This condition is extremely rare, but there have been a few cases reported [ 1,10]. Recently, we encountered a newborn child with this deformity. It was definitely diagnosed by neuroradiologic examinations. The main diagnostic points and their importance are described together with a discussion on embryology. Case Report A 1-day-old male was born by Caesarean section at full term with a body weight at birth of 3500 g, cranial circumference of 35.2 cm, and 5-minute Apgar score of 10. Facial abnormalities such as hypertelorism and deformed anterior nares were noted at birth. Because he was dyspneic during nursing, he was transferred to our clinic. Hypertelorism, unequal anterior nares, and micrograthia were noted as facial abnormalities at admis-
Address reprint requests to: Takashi Hayashi, M.D., Department of Neurosurgery, St. Mary's Hospital, 422 Tsubuku Honmachi, Kurume 830, Japan.
© 1985 by ElsevierSciencePublishing Co., Inc.
sion. Both nasal cavities were completely obstructed by abnormal bony tissue about 3 cm from the anterior border of the nares. Neurologically, no obvious abnormality was noted and the biochemical findings in the blood were normal.
Examinations In the anteroposterior view of the craniogram, a bony defect was noted in the base of the frontal skull. In the lateral view, the sella turcica was normal and the limbus sphenoidal was noted, but the frontoethmoidal suture could not be identified. In the coronal section of the tomograph, a bony defect was noted in the base o f the frontal skull with a maximum diameter of about 1.8 cm in the ethmoid bone. N o tumor density was apparent but no structure was noted in the nasal cavity (Figure 1). A computed tomography scan revealed an isodensity zone representing brain tissue in the transverse plane in the nasal cavity, as well as a deeply depressed frontal skull base. Both orbitas were separated, indicating hypertelorism. In addition, obvious enlargement o f the lateral ventricles was noted, suggesting congenital hydrocephalus. In the coronal and sagittal computed tomography scans, brain tissue was clearly seen to protrude into the nasal cavity (Figure 2). In a lateral arteriogram of the right internal carotid artery, the olfactory artery, distributed to the rectal gyrus and the olfactory groove, appeared to be situated lower than usual and extended downward running into the nasal cavity (Figure 3). In an arteriogram of the left internal carotid artery, nearly the same findings as on the right side were obtained. Bilateral pericallosal arteries were straightened and extended because of the hydrocephalus but no findings suggesting a defect of the corpus callosum were noted.
Operation Bifrontal craniotomy was performed with the patient in the supine position and ventricular drainage was carried out from the anterior horn of the right lateral ventricle. First, when the dura mater was gradually stripped from 0090-3019/85/$3.30
652
Surg Neurol 1985;24:651-5
Hayashi et al
Discussion
Figure 1. Frontal tomography of the skull shows defect of cribriform plate (arrowheads) and abnormal structures in the nasal cavity.
the inner table of the frontal skull base on both sides under a surgical microscope, the crista galli could not be seen, but the base of the frontal skull was found to be deeply depressed into the ethmoid sinus proper. At this site, the dura mater of the frontal skull base and the bottom of the frontal lobe were displaced inside the nasal cavity (Figure 4). The bottom of the depressed frontal skull base was composed of rough connective and cartilaginous tissues. The optic nerves on both sides appeared to enter the optic canal normally and be of normal color and size. However, the olfactory bulbs and tracts were absent on both sides. The dura mater was tightly sutured, the bony defect in the base of the frontal skull was closed with Lyodura and also with frontal bone, and Lyodura was applied to the reconstructed base of the skull to prevent liquorrhea. Repositioning of the meningoencephalocele and plastic surgery of the frontal skull base were completed. At a second-stage operation, plastic surgery of the nasal cavity is anticipated.
Basal meningoencephalocele is classified into four types depending on the site of the bony defect [12], i.e., the transethmoidal type where the rumor protrudes from the defect in the ethmoid bone into the nasal fossa; the sphenoethmoidal type where the bony defect is present between the sphenoid and ethmoid bones; the transsphenoidal type where the bony defect is present in the sphenoid bone, especially the sella turcica, and a tumor is seen in the epipharnyx; and the sphenoorbital type where the tumor protrudes from the superior orbital fissure into the orbit. In our present case, the transethmoidal type was diagnosed because the limbus sphenoidal was visualized radiologically, the ethmoid bone was nearly completely absent, and the crista galli was not found at operation. Bony defects of the transethmoidal type reported thus far are relatively small and often limited to the cribriform plate on one side [1], but the bony defect in our case was large and was found to involve nearly the entire ethmoid bone, a finding that may be said to be characteristic. In basal meningoencephalocele, the tumor, unlike those at other sites, is often not detectable from the outside. Gisselsson [6] mentioned the following as symptoms of basal meningoencephalocele: (a) intranasal rumor and obstruction from the time of birth, (b) pulsation of the rumor synchronous with the pulse or respiration, (c) complications of facial deformities such as hypertelorism, and (d) leakage ofcerebrospinal fluid from the nose, meningitis, etc. The characteristics of this disease are, in addition to an intranasal tumor, facial deformities such as hypertelorism, harelip, and cleft palate [6,7,10,11]. With these malformations, agenesis of the corpus callosum [10] and congenital hydrocephalus [5] may also be present. In our case, obstruction of the nasal cavity, hypertelorism, and congenital hydrocephalus were identified. Such congenital malformations indicate the origin of this disease in the embryonic stage and embryologic studies on the pathogenesis of this disease have been conducted by various workers. A representative study is the adhesive theory of Geoffery St. Hilliare et al [9], which states that in the embryonic period, disturbance appears in the separation of epidermal ectoblast and nervous system ectoblast, causing a disturbance in the development ofmesoblastic tissue, i.e., the bone. Other theories include Steinberg's theory of neural tube obstruction and disturbance [8], Spring's theory of ventricular pressure increase in the embryonal period [6], and Wiese's theory of disturbance in the development of bone [13], but none of these theories has been fully accepted. Complications by multiple deformities, mainly median fissures of the skull, face, and brain, suggest that this disease belongs to the series of median cranioencephalic dysraphia mentioned by de Morsier [3].
Transethmoidal Encephalomeningocele
Surg Neurol 1985;24:651-5
653
A
Figure 2. (A) Direct coronal and (B) sagittal computed tomography scans reveal meningoencephalocele at the ethmoidal region associated with congenital hydrocephalus. (C) Schematic drawing ol the transethmoidal encephalomeningocele in our case. M = maxilla~ bone: N = nasal bone: S = sphenoid bone.
Herniated brain
Figure 3. Lateral arteriogram of right internal carotid artery shows that the olfactory artery originatedfrom the proximal portion of anterior cerebral artery and herniated into the nasal cavity through the skull schesis.
654
Surg Neurol 1985;24:651-5
Figure 4. Operative photograph shows a wide deject of the frontal skull base in the interorbital region. Brain tissue covered with meninges was herniated into the nasal cavity through the bony defect.
The treatment is solely surgical and the first successful operation was performed by Fenger et al (1895) [4]. Richter et al in 1813 were the first to report a case o f this disease [6] but the interval up to the first surgical operation was 85 years. T h e reason for this is the fact that preoperative diagnosis could not be precisely performed and intracranial surgery was seldom undertaken. Because most cases were diagnosed erroneously as nasal polyps, the tumor was excised by intranasal manipulation, resulting in severe postoperative complications such as meningitis and even death. However, the rate of success has become very high since Dandy in 1929 [2] and Gisselsson in 1947 [6] began operating upon these malformations intracranially. The advantages o f intracranial operations include the fact that the operative procedure can be performed in a "clean" place compared with the intranasal operation, a wide field o f vision can be obtained, reposition of the hernia is easy, and the bony defect can be treated under watertight conditions. However, the most important point seems to be that the
Hayashi et al
operative method can be decided with a precise diagnosis, which also greatly influences the prognosis. In our case, reposition of the cranial dysraphia was performed by intracranial manipulation and the course has been good during the 3 postoperative months, with no sign of meningitis.
References I. Blumenfeld R, Skolnik EM. lntranasal encephaloceles. Arch Otolaryngol 1965;82:527-31. 2. Dandy WE. The operative treatment for certain cases of meningocele or encephalocele into the orbit. Arch Ophthalmol 1929;2:123-32. 3. De Morsier G. Median cranioencephalic dysraphia and olfactogenital dysplasia. World Neurol 1962;3:485-506. 4. Fenger C. Basal hernias of the brain. AmJ Med Sci 1895;109:1-17. 5. Gerlach J. Missbildungen des Gehirns und der Hirnhaute. Die Diencephalon. In: Olivecrona H, Tonnis W, eds. Handbuch der Neurochirurgie, IV/I. Berlin: Springer-Verlag, 1960:169-83. 6. Gisselsson L. lntranasal forms of encephalomeningocele. Acta Otolaryngol 1947;35:519-31. 7. Lewin ML, Shuster MM. Transpalatal correction of basilar meningocele with cleft palate. Arch Surg 1965;90:687-93. 8. Mood GF. Congenital anterior herniations of brain. Ann Otol Rhinol Laryngol 1938;47:391-401. 9. Pollock JA, Newton TH, Hoyt WF. Transsphenoidal and trans-
Transethmoidal Encephalomeningocele
ethmoidal cncephalomeningoceles: a review of clinical and roentgen features in 8 cases. Radiology 1968;90:442-53. 10. Sakoda K, Uozumi T, Hirakawa K, Harada Y, Chikuie S, Sakaki U, Ibuki Y. Sphenoethmoidal meningoencephalocele associated with agenesis of corpus callosum and median cleft lip and palate. Report of two cases. Brain Nerve (Tokyo) 1979;31:947-53. 11. Stuart EA. An otolaryngologic aspect of frontal meningocele. Arch Otolaryngol 1949;40:171-4.
Surg N e u r o l 1985;24:651-5
655
12. Suwanwela C, Suwanwela N. A morphological classification of sincipital encephalomeningoceles. J Neurosurg 1972;36:201- l l. 13. Wiese GM, Major MC, Ludwig GK, Colonel MC, William MM. Transsphenoidal meningohydroencephalocele. J Neurosurg 1972;36:475-8.