Frontoethmoidal Research Articles

MORPHOMETRIC ANALYSIS OF ETHMOIDAL FORAMEN IN ADULT DRY INDIAN SKULL

Ethmoid bone is located in the anterior part of the base of the cranium between the orbits. The medial orbital wall separates the content of the orbit from the ethmoidal air sinuses. The anatomical landmarks of orbital cavities are very much important during orbital surgeries which includes surgery of anterior cranial fossa and endonasal microsurgeries of ethmoidal region. On this medial orbital wall, the anterior and the posterior ethmoidal foramina are located along the frontoethmoidal suture and more anteriorly to the optic canal and these are very much important in orbital surgeries. This prospective observational study was undertaken to study the morphology of Ethmoidal foramen in adult dry Indian skull and to study the clinical implications of ethmoid foramen. A total 50 dry adult skulls were measured for the ethmoidal foramen. It was reported that the mean of posterior ethmoidal canal right and left was 2.09±0.75mm and 2.31±0.132mm respectively. The study concluded that to ensure the safety of surgical procedures to be performed among ethmoid foramen it is very important to measure the various landmarks; as the anatomical variations can cause problems and leads to surgery related complications.

Are the Ethmoidal Foramina Through the Frontal Bone, Ethmoid Bone, or Frontoethmoidal Suture?

To investigate the locations of the anterior, middle, and posterior ethmoidal foramina and their relationships to the frontoethmoidal suture. One hundred twenty sides from sixty adult human skulls were used. Specimens with significant damage to the medial orbit wall were excluded. The number of ethmoidal foramina (anterior, middle, and posterior) on the medial orbital wall and the relationship of each foramen to the frontoethmoidal suture were recorded and classified as follows: Type I: superior to the frontoethmoidal suture; Type II: on the frontoethmoidal suture; Type III: inferior to the frontoethmoidal suture. Of the ninety-four sides, fourteen (14.9%) had one foramen, sixty-two (66.0%) had two , and eighteen (19.1%) had three. In total, 192 ethmoidal foramina were observed. Among the fourteen sides with one foramen, eight foramina were anterior and six were posterior. Among the 192 ethmoidal foramina, 162 were eligible for fur ther classification (74 anterior, 14 middle, and 74 posterior). Types I, II, and III ethmoidal foramina were found in 38.3% (62/162), 61.7% (100/162), and 0% (0/162), respectively. Our current study found a higher incidence of type I than previously reported. It is important to be aware of the significant incidence of foramen variations when the medial orbit wall is manipulated during surgery. Unless caution is observed, an inadvertent surgical injury can occur and lead to life-threatening complications. Therefore, a good understanding of orbital anatomy and its potential variations is critical for improving patient out comes.

External Frontoethmoidectomy in the University of Port Harcourt Teaching Hospital, Rivers State, Nigeria

Introduction: External Frontoethmoidectomy is an open surgical procedure employed to remove disease from the frontal and ethmoidal sinuses. Pathologies in the para nasal sinuses can be managed endoscopically, however, the limited availability of skilled man power in endoscopic sinus surgeries, and the dearth of its instruments in this region, remains a challenge in most tertiary health care centres in Nigeria, thus promoting the use of external approach to manage sinus diseases. Method: This was a retrospective study of 10 patients who had Frontoethmoidectomy over a 6 year period, from January 2012 to December 2017.Their medical records were retrieved from operating theatre, and Ear, Nose and Throat ward. Information retrieved included their age, gender, presenting complain, indication for surgery and length of hospital stay. Results were presented in tables and figures. Results: Among the 10 patients, there were 7 males and 3 females, 6 (60%) were aged 10-19 years. The indications for surgery was Fronto-ethmoidal mucocele in 3 patients and frontal mucocele in 2 patients, frontal sinusitis with intracerebral abscess in 1 patient, pan sinusitis with sinu-cutaneous fistula in 1 patient, potts puffy tumor in 1 patient, fronto-ethmoidal abscess, and fronto-ethmoidal osteoma in 1 patient each. Nasal obstruction was the commonest complain 7(70%), followed by frontal headache 4(40%).The average hospital stay among the patients was 6 days. Conclusion: External fronto-ethmoidectomy has remained the mainstay of treatment for frontal and ethmoidal sinus pathologies in this region, despite the advent of endoscopic sinus surgery. Early presentation for specialist otorhinolaryngological management can reduce morbidity and mortality.

Ectopic orbital meningioma: a retrospective case series

BackgroundTo evaluate the ophthalmic manifestations and radiographic features of ectopic orbital meningioma to improve diagnostic accuracy.MethodsPatient data from patients admitted to our institution during a 217-month period from August 1999 to September 2017 were included. Patient ophthalmic manifestations, radiographic features (CT and MRI), diagnosis, pathology, therapeutic regimens, and prognosis were retrospectively reviewed.ResultsSix patients with ectopic orbital meningioma were identified. The mean age at the first visit was 33.2 years (range, 7–56 years). All six patients displayed manifestations of exophthalmos, upper eyelid oedema, and motility impairment with a mean history of illness of 20.3 months (range 3–72 months). Optical lesions were located in the superonasal extraconal compartment (3/6, 50%), bitemporal extraconal compartment (1/6, 16.7%) and orbital intraconal compartment (2/6, 33%). Radiographic features were ill-defined, heterogeneous, enhancing soft tissue masses with extraocular muscular adhesion (6/6, 100%) and calcification (1/6, 16.7%), not adjacent to the optic nerve and not extending along the dura. Six cases were treated intraoperatively with complete surgical resection, indicating that all lesions were independent of the optic nerve and sphenoid ridge. The histopathologic classification was mostly of meningothelial cells (5/6, 83%). Immunohistochemistry revealed EMA and vimentin to have positive expression in all six cases, while two cases were calponin-positive and strongly expressed in the olfactory bulb. Postoperatively, lesions caused no visual impairment, and there were no cases of recurrence.ConclusionsEctopic orbital meningiomas are rare tumours that are not easily diagnosed without postoperative histopathology. This report highlights some of the distinguishing features of isolated orbital lesions, especially around the location of frontoethmoidal suture. Accompanying upper eyelid oedema and eye mobility restriction were observed to be dissimilar to other orbital tumours. In these cases, a diagnosis of ectopic orbital meningioma should be considered.

Fronto Ethmoidal Mucocele Associated with Type 4 Kuhn Cells.

A mucocele is an epithelial lined mucous containing sac completely filling the sinus and capable of expansion. We report a case with unilateral frontoethmoidal mucocele in relation with type IV Kuhn cell. A 26 year old man came to theENT department at SDUMC, Tamaka, Kolar, presenting complaints of proptosis of left eye since 3 years. After detailed examination and investigations patient was Diagnosed to have mucocele of left frontoethmoidal region. Intraoperatively we found a rare picture of type IV kuhn cells completely seated in the frontal sinus. After externally assisted modified Lothrop's approach, marsupialization of mucocele was donein the nasal cavityand symptoms of the patient relieved. We state that, in cases of frontoethmoidal mucocele, externally assisted modified Lothrop procedure offers an alternative for endoscopic management of frontoethmoidal mucocele for the complete clearance of disease.

How I do it. 3D endoscopic treatment of metopic craniosynostosis through a single incision.

Endoscopic approaches for craniosynostosis are a growing field in pediatric neurosurgery. In metopic synostosis, previous reports for complete fronto-orbital remodeling have proposed an intervention with multiple incisions (bregmatic, tarsal, and preauricular) to open frontonasal and frontoethmoidal synostotic sutures, and orbital roof. We propose a technique to complete all these osteotomies with a unique incision anterior to the bregmatic fontanel under 3D endoscopic vision, and review possible complications, limits, and pitfalls. Under endoscopic assistance, a complete fronto-orbital remodeling could be completed with a unique incision without mayor drawbacks.

Positional Relationship of Ethmoidal Foramens With Reference to the Nasion and Its Significance in Orbital Surgery.

The aim of the study was to elucidate the positional relationship of the ethmoidal foramens (EFs) with reference to the nasion to facilitate prediction of the exact location of EFs, the optic canal (OC), and the frontoethmoidal suture (FS), and thereby avoid complications during complex surgery involving the medial wall of the orbit. One hundred two intact orbits of 57 embalmed cadavers were dissected in this observational anatomic study. Nasion' (N') was defined as the intersection point of the medial orbit margin with the horizontal line through the nasion, and this was used as a reference point. N'-OC was defined as the straight line joining N' and OC. The locations of the anterior ethmoidal foramen (AEF), posterior ethmoidal foramen (PEF), and OC were determined with reference to N'. The vertical distances from N'-OC to EFs and to FS were also determined. The N'-AEF, AEF-PEF, and PEF-OC distances were 18.4, 15.3, and 8.3 mm, respectively. Vertically, AEF and PEF were situated at 0.2 mm below and 0.4 mm above N'-OC, respectively. At the same reference points, N'-OC was situated at 0.4 and 0.6 mm above FS, respectively. N', AEF, PEF, and OC were considered to be situated on the same straight line, and N'-OC could be regarded as coinciding with FS. This means that N' is an easily identifiable and reliable landmark for identifying EFs, OC, and FS. Our navigational parameters with reference to N' will help surgeons to enhance the safety of orbital surgery.

The frontoethmoidal architecture: a developmental point of view

The anatomy of frontal sinus drainage pathway (FSDP) and surrounding spaces is extremely complex and variable. Its anatomical variability can be simplified based on the knowledge of the developmental mechanism of the frontal recess. The frontal sinus develops from the 13th week of intrauterine life to the age of twenty through a number of well-known steps of progressive extension within the frontal bone. Its development results from an upward epithelial migration of the anterior ethmoidal cells that penetrate the inferior aspect of the frontal bone between its two diploic plates. Even though this developmental theory is almost universally accepted, only few Authors focused on the formation of FSDP prior to the extramural pneumatization (1-2). The results of the present study conducted on 14 human heads match with the developmental model proposed by Terracol and Ardouin (2), in fact a number of significant associations are conform to the process of growing of the frontal sinus from one out of the three primordial cells (i.e. orbital, nasal, or bullar cell). In this model, renewed in view of the observation of the present study, the hierarchical order of growing among primordial cells determines the final frontoethmoidal architecture.

Three-dimensional evaluation of the danger zone of ethmoidal foramens on the frontoethmoidal suture line on the medial orbital wall.

It is clear that the importance of the ethmoidal foramen (EF) is based on its vascular contents. The frontoethmoidal suture (FS) line is recommended as more reliable navigational landmark for identifying the EF. The vertical orientation between the EF and the FS line was studied in 188 orbits using a computer software program. 146 anterior EFs (77.7 %) and 42 anterior EFs (22.3 %) were situated in the FS line as intrasutural and extrasutural, respectively. 146 posterior EFs (77.25 %) and 8 posterior EFs (4.25 %) were presented as intrasutural and extrasutural, respectively. Although accessory EFs were detected in 25.5 % specimen exhibited an extrasutural location. Majority of the EFs (1-4 EFs) were situated on the FS line. The mean distances from the FS and the anterior EF, the posterior EF and the accessory EF were measured as 2.1 ± 0.5, 2.0 ± 1.5 and 2.3 ± 1.2 mm, respectively. The range of the distances from the FS to the anterior EF, posterior EF and accessory EF were -1.2 to 3.32 , -1.02 to 5.76 and -1.1 to 3.65 mm, respectively. The ranges of EF changed within 1-6 mm. As the FS is not a single point, it is more suitable to make the incision 7 mm above the suture line. The data from this study to help the orbital surgeons explain and avoid unexpected hemorrhage during the orbital procedures such as posttraumatic orbital reconstruction, orbital tumor resections, anterior skull base reconstruction, and orbital decompression surgery.

Frontal sinus drainage pathway and uncinate process: a single morphofunctional unit with a complex anatomy

The aim was to study the anatomical variability of the frontal sinus (FS) drain - age pathway (FSDP), the uncinate process (UP) and the relative air spaces. For this purpose, 14 human heads were endoscopically dissected after a cone-beam CT scan. Several features were assessed both radiologically and in the lab setting. Most of the anatomical features were classified according to the Bent and Kuhn classification modified by Wormald (1). The FSDP was medial to the UP in 82% and lateral in 18% of the cases. The Agger-Nasi Cell (ANC) was found in 100% of cases, a supraorbital pneumatization in 71.5%, a frontal bulla in 14%, a suprabullar cell in 78.5%, a suprab - ullar recess in 23%, an inter-frontal-sinus septal cell in 14%, a concha bullosa in 28.5% of cases. The frontoethmoidal Kuhn cells (K cells) were absent in 32%, type 1 was found in 39%, type 2 in 25%, type 3 in 4% and type 4 in no one case. The medial location of the FSDP respect to the UP was found to correlate with the presence of type 1-4 K cells, while the lateral location significantly correlated with the suprabul - lar recess, which was mostly absent when a suprabullar cell was present. The results of this study should be explained considering the development of the FS based on the description of frontoethmoidal area by Terrier et al. (2) In fact, when the FS arises from a “nasal cell”, the FSDP is medial to the UP and K cells develop, as resulted in the present study; on contrary, when the FS arises from an “orbital cell”, the FSDP is lateral to the UP and no K cells are found. Furthermore, when the FS develops from a “bulla cell”, the pneumatization occurs laterally to the UP. This fact should be explained considering the correlation between the suprabullar recess, which is a sign of “bulla cell” origin, and the lateral location of the FSDP. In conclusion, this data could also support and explain the presence and formation of several other anatomi- cal variations, such as the frontal bulla and the inter-frontal-sinus septal cell.

Congenital malformation of lamina orbitalis ossis ethmoidalis

Background: The thinnest portion of the medial wall of the orbit is Lamina orbitalis ossis ethmoidalis which separates the ethmoidal sinuses from the orbit. Congenital bony malformation of orbit and anatomical variation of ethmoidal sinuses are important in terms of the risk of complication development during endoscopic sinus surgery and to understanding the pathophysiology and spread of sinus disease.Materials and Methods: Accordingly the present study was designed to fi nd out the congenital malformation of medial wall of the orbit in relation to lamina orbitalis ossis ethmoidalis. The study was carried out using 100 dried adult human skulls and twenty six human cadavers irrespective of sex were obtained from the Department of Anatomy - Mayo Institute of Medical Sciences-Barabanki, Department of Anatomy - Melaka Manipal Medical College - Manipal and Department of Anatomy - KMCT Medical College, Manassery - Calicut.Results: In three skulls (2.380%) we noted unilateral unusual hole at the junction of medial wall and roof of orbit with dimensions of 2.3 cm long and 1 cm height in two skulls and another unusual vertical hole at the anterior part of medial wall and roof of orbit with dimensions of 2 cm height and 1 cm width. We also noted few ethmoidal cells extended in to the orbital plate and fovea ethmoidalis of the frontal bone.Conclusion: Congenital defective formation of bony orbit and variable anatomy of paranasal sinuses noted in this study is may be due to the defective formation of Lamina orbitalis ossis ethmoidalis from the lateral part of the nasal capsule near the fronto ethmoidal suture such comprehensive knowledge is necessary to understand the various disorders of this region and to avoid complications during surgical procedures involving this area.DOI: http://dx.doi.org/10.3126/ajms.v6i2.10534Asian Journal of Medical Sciences Vol.6(2) 2015 91-94

An Anatomical Study of the Positional Relationship Between the Ethmoidal Foramina and the Frontoethmoidal Suture

To examine the positional relationship between the ethmoidal foramina and the frontoethmoidal suture. Eighty-four orbits of 42 Japanese cadavers (24 male and 18 female cadavers; average age at death, 81.0 years; range, 61-101 years), fixed in 10% buffered formalin, were used for investigation. The most anterior or posterior ethmoidal foramen was defined as the anterior or posterior ethmoidal foramen, respectively. All the intermediate foramina were determined as the accessory foramina. The vertical distances from the frontoethmoidal suture to the anterior, posterior, and accessory ethmoidal foramina were examined. Seventeen anterior ethmoidal foramina (20.2%) were situated above the frontoethmoidal suture (mean distance, 1.8 mm), and 2 posterior ethmoidal foramina (2.3%) were situated at 1.0 mm and 1.5 mm above the suture. Although accessory ethmoidal foramina were detected in 32 orbits (38.1%), one accessory foramen (middle ethmoidal foramen) was identified in 30 orbits, and 2 foramina (additional deep-middle ethmoidal foramina), in 2 orbits. One middle ethmoidal foramen (3.1%) and 1 deep-middle ethmoidal foramen (50.0%) were located at 1.5 mm above the suture. In total, 2 of the 34 accessory ethmoidal foramina (5.9%) exhibited the extrasutural location. Several ethmoidal foramina were situated above the frontoethmoidal suture. The anterior ethmoidal foramen most frequently showed the situation, followed by the accessory and posterior foramina, in order. Our findings help predict the anatomical variations in the location of the ethmoidal foramina in relation to the frontoethmoidal suture, thereby enhancing safety for medial orbital wall surgery.

Frontobasal Suture Distraction Corrects Hypotelorism in Metopic Synostosis

Spring-assisted cranioplasty has been demonstrated to correct hypotelorism associated with metopic synostosis. In addition, the fronto-orbital axis rotates toward a more normal orientation. We postulated that spring-induced shear forces and subsequent displacement across the frontobasal sutures are the primary initial mechanisms for change in cranio-orbital morphology. Sixteen consecutive patients (32 orbits) with trigonocephaly operated on between 1999 and 2004 were studied retrospectively. After frontal remodeling, a spring was placed across the released metopic suture. Preoperative and 6-week postoperative cephalograms were used to measure the relative translation of the medial orbital wall from the midline at fixed vertical distances above and below the frontoethmoidal suture (FES). The vertical height of the spring above the frontonasal suture and the patient's age were analyzed with respect to the increase in bony interorbital distance (BIOD). There were significant increases in movement of the medial orbital wall above the FES at each measurement point (P < 0.001). There was no significant postoperative movement of the medial orbital wall below the FES at any measurement point. The relative movements above the suture suggest a degree of plastic deformation adjacent to the suture.There was no significant correlation between the age of patient or the height of the spring above the frontonasal suture and the increase in BIOD. Tensile spring forces are transmitted directly to the frontoethmoid suture. Most initial increases in BIOD and altered intraorbital morphology are due to distraction of cranial base sutures rather than plastic deformation.

One-Stage Operation for a Frontoethmoidal Encephalomeningocele Associated with Ventriculomegaly-A Case Report

Encephalomeningoceles, especially in the frontoethmoidal region, are a form of neural tube defect which affect patients in Southeast Asia more commonly than those in Western countries. We performed a 1-stage reconstruction and ventriculoperitoneal (V-P) shunt placement for a frontoethmoidal encephalomeningocele in an 18-year-old male. We used the 3D reformation computed tomography (CT) and magnetic resonance imaging (MRI) to delineate the skull defect and the exit pathway of the herniated brain tissue and to determine the surgical strategy. The frontoethmoidal encephalomeningocele was completely resected via a 1-stage operation. Neither hydrocephalus nor cerebrospinal fluid (CSF) rhinorrhea was noted after the operation. However, Klebsiella pneumoniae meningitis was diagnosed 2 weeks after the operation. The infection was cured by the use of meropenem. A good aesthetic result was achieved. A 1-stage operation is necessary for large frontoethmoidal encephalomeningoceles and should be performed as early as possible in order to resect the mass, to reconstruct the defect, and to restore the aesthetic appearance with assistance of 3D reformation CT and MRI. A V-P shunt or extraventricular drainage (EVD) catheter placement needs to be considered during the operation for large encephalomeningoceles coexisting with hydrocephalus.

Involvement of the Basilar Coronal Ring in Unilateral Coronal Synostosis

Unilateral coronal synostosis denotes one-sided premature fusion of the frontoparietal suture. However, this is only one component of the coronal hemi-ring that includes the contiguous frontoparietal, frontosphenoidal, and frontoethmoidal sutures. Possible fusion of the basilar sutures in unilateral coronal synostosis is poorly documented. The authors retrospectively reviewed the radiographic records of 91 patients with unilateral coronal synostosis who were evaluated in their unit between 1986 and 2003. Fifty-one computed tomography scans were of sufficient quality to adequately assess the basilar sutures. Each suture in the coronal hemi-ring (frontoparietal, frontosphenoid, and sphenoethmoid) was assessed on axial images for evidence of synostosis, extent and location of fusion, and cranial base angulation. The data were analyzed using SAS statistical software (SAS, Cary, N.C.). One frontoparietal ("coronal") suture was fused in all 50 patients. Synostosis was incomplete in 19 patients; specifically, the superior and inferior portions of the frontoparietal suture were patent. Fourteen of the 19 scans showing partial frontoparietal fusion were in infants less than 5 months of age. Scans were grouped according to extent of fusion in the basilar coronal hemi-ring: group I (n = 15), the frontosphenoidal suture was open on the affected side, whereas in group II (n = 36), there was variable synostosis in the lateral portion of the ipsilateral frontosphenoidal suture. Patients in group I were significantly younger than those in group II at the time of computed tomographic study (p < 0.001). Furthermore, group I patients were more likely to have incomplete frontoparietal fusion, as compared with group II (p < 0.001). The frontosphenoidal suture was patent in 100 percent of patients younger than 3 months, in 43 percent of those between 3 and 5 months old, and in 0 percent of patients older than 5 months at the time the scan was obtained. There was also a trend toward a larger cranial base angulation in group II, although this difference was not significant (p = 0.33). Seven patients were syndromic; however, their mean age (207 days) at the time of computed tomography was not statistically different from that of patients without a detectable mutation (188 days), nor did the cranial base angulation differ in this subgroup. The authors conclude that unilateral coronal fusion begins in the middle of the frontoparietal suture and extends superiorly and inferiorly. There also is age-dependent, progressive involvement of the lateral frontosphenoidal suture between 3 and 5 months of age. Nevertheless, synostotic extension into the basilar coronal hemi-ring is not associated with increased cranial base angulation.

Coronal Ring Involvement in Patients Treated for Unilateral Coronal Craniosynostosis

The etiopathology of the clinical entity normally referred to as unilateral coronal synostosis is commonly used to connote unilateral fusion of the frontoparietal suture. However, other sutures in the coronal ring may exhibit synostosis concomitant with or independent from frontoparietal synostosis and give rise to similar clinical phenotypes. This study retrospectively analyzes high-resolution computed tomographic data sets to determine patency of sutures within the coronal ring. Computed tomographic scan digital data from 33 infants who subsequently underwent surgical correction of unilateral coronal synostosis were assessed for sutural patency using Analyze imaging software. The frontosphenoidal suture was subdivided into intraorbital frontosphenoidal and extraorbital frontosphenoidal portions, and the patency of the frontoethmoidal suture was also assessed. Patients were sorted into two groups on the basis of the status of their frontosphenoidal sutures: group 1 had patent frontosphenoidal but synostotic frontoparietal sutures (n = 21) and group 2 had both frontosphenoidal and frontoparietal synostoses. Observer reproducibility was tested. The vertical and horizontal dimensions of the bony orbit and the endocranial base deflection angle were measured with the observer blinded with regard to sutural status group. Frontoethmoidal synostosis was not noted in any patients in either group. Two patients had no frontoparietal suture synostosis with isolated intraorbital frontosphenoidal and extraorbital frontosphenoidal suture closures. Suture diagnosis reproducibility was 99 percent. In group 1, the ipsilateral-to-contralateral vertical orbit dimension ratio averaged 1.11, whereas in group 2 it averaged 1.04 (p < 0.05). The ratio of horizontal orbit measurements was not significantly different between groups. In both groups, the endocranial base was deflected ipsilateral to the synostotic frontoparietal suture, with an average angle of 12 degrees in group 1 and 17 degrees in group 2 (p < 0.005). The extent of synostosis along the coronal sutural ring contributes to the dysmorphology of the orbit and the endocranial base deflection in patients whose clinical phenotypic diagnosis is unilateral coronal synostosis.

Frontal plagiocephaly secondary to synostosis of the frontosphenoidal suture

Frontal plagiocephaly may arise from either synostotic or deformational forces. Deformational causes of frontal plagiocephaly can be distinguished from synostotic causes by differences seen on physical examination, which can then be confirmed by skull x-ray films and if necessary three-dimensional computerized tomography (CT). Unilateral coronal synostosis is the main synostotic cause of frontal plagiocephaly, although it has also been seen with fusion of the frontozygomatic suture. In several syndromes presenting with bilateral coronal synostosis, fusion of the frontosphenoidal and frontoethmoidal sutures is also present. The authors report, for perhaps the first time, a case showing synostotic frontal plagiocephaly secondary to fusion of the frontosphenoidal suture alone. Although the phenotypic appearance is superficially similar to that seen in unilateral coronal synostosis, analysis of the cranial base shows markedly different effects: angulation of the anterior cranial base with respect to the posterior cranial base away from the synostotic side and angulation of the posterior cranial base with respect to the midpalatal suture also away from the synostotic side. In unilateral coronal synostosis, both angulations are toward the synostotic side. These effects on the cranial base alter its relationship to the cranial vault and the facial skeleton. Most important, frontal plagiocephaly secondary to fusion of the frontosphenoidal suture should not be overlooked as being deformational. Because this fusion is difficult or impossible to visualize by skull x-ray films, three dimensional CT must be obtained in cases that are not clearly identified as deformational plagiocephaly by physical examination.

The mucoceles or pyoceles of the paranasal sinuses.

Fifty-five mucopyoceles in 53 patients were diagnosed during the 10-year period from 1982 to 1992 in our department. These included 8 from the frontal sinus, 25 from the maxillary sinus, 10 from the ethmoidal sinus, 1 from the maxillary and ethmoidal sinuses, 7 from the frontoethmoidal sinuses and 4 from the sphenoethmoidal sinuses. The patients ranged in age from 8 to 78 years (mean 47.1 years). The ratio of males to females was 31 to 22. The rhinologic symptoms occurred most often in maxillary mucopyoceles and were rare in the other groups whereas ophthalmic symptoms were noticed in most of the cases. All of the cases received surgery and postoperatively most of the initial symptoms subsided except that two patients still had occasional diplopia and one did not recover at all from complete blindness. Two cases had a recurrence and one suffered from subarachnoid hemorrhage shortly after discharge. Surgery is the only treatment modality for mucopyoceles and the building of a new patent communication between the lesion and nasal cavity is important for the success of this surgery.

Lateral canthal advancement of the supraorbital margin

In coronal synostosis, in addition to fusion of the coronal suture, the frontosphenoidal and frontoethmoidal sutures are usually closed. A linear craniectomy along the coronal sutures does not affect the synostotic process at the base of the skull. The facility with which the supraorbital margin could be mobilized in Tessier's method of craniofacial repair suggested to us that we could easily modify our approach to coronal synostosis and advance the supraorbital margin, creating an artificial suture at the base of the skull and allowing for proper correction of this disorder. During the past 3 years, we have treated 15 patients with coronal synostosis by this technique, which we have termed lateral canthal advancement. The method of this form of surgical management and its results are discussed.

OSTEOMAS OF PARANASAL SINUSES AND THE MASTOID PROCESS

Osteomas that arise in the paranasal sinuses are not common. Occasionally they are discovered in routine roentgenologic examination of the sinuses. They are not diagnosed clinically or even suspected of being present until either evidence of intracranial complications becomes manifest or external deformities appear. From time to time, articles have appeared that contain reports of cases and give the number of cases previously reported. It is not the purpose of this paper to give a detailed review of the literature; rather, it is to stress methods of handling cases. In 1935 Dr. Carmody reviewed the cases reported up to that time. <h3>ETIOLOGY</h3> The etiology of these bony growths never has been determined. The ethmoid bone is developed from cartilage and the frontal bone is developed from membrane. Osteomas develop frequently at the site of the frontoethmoidal suture. Arnold¹advanced the hypothesis that cartilaginous rests were present and that these