Clinico-anatomic study of the spina nasalis ossis frontalis and its role within the scope of frontal sinus surgical approach

BACKGROUND: During endonasal frontal sinusotomy using the sharp spoon (endonasal frontal sinus surgery type II according to Draf or May and Schaitkin) a solid piece of bone is frequently encountered anterior to the neo-ostium. This bone may be referred to as a "nasal spine". A prominent spine may render a sinusotomy difficult or even impossible. METHODS: A maximum endonasal frontal sinusotomy was performed on 36 anatomical specimens by means of a sharp spoon producing neo-ostia of 7 x 5 mm on average. The dimensions of the remaining nasal spine were measured subsequently together with the diameter of the inferior frontal sinus, the thickness of the anterior frontal sinus wall, and the distance from the neoostium to the anterior ethmoidal artery. RESULTS: Almost every specimen (97%) showed a relevant nasal spine. The average height of the spine was 10 mm. The anterior-posterior dimension was 6 mm on average. A correlation was found between the nasofrontal angle and the a.-p. dimension of the spine: the more acute the angle, the thicker the spine was. In three out of four specimens the neo-ostium was separated by just one anterior ethmoidal cell from the anterior ethmoidal artery. CONCLUSIONS: In the majority of the specimens a sufficient endonasal approach to the frontal sinus could be obtained by enlarging the natural ostium as described by Draf or May and Schaitkin. The anterior ethmoidal artery is a valuable landmark for locating the ostium. The maximum diameter of the frontal sinus approach in frontal direction can be estimated by measuring of the nasofrontal angle.     

The clinical assessment of attachment in children under five

Dural arteriovenous malformations (AVMs) are considered to be acquired lesions that develop secondary to venous obstruction, which sometimes happens in head trauma. However, there has been a report of an anterior cranial fossa dural AVM that occurred independently of a history of head trauma, and there has been speculation that these malformations are congenital. The authors recount their experience with a patient who had an anterior cranial fossa dural AVM that was discovered incidentally. The lesion was fed by the bilateral anterior ethmoidal arteries and drained into the superior sagittal sinus via frontal cortical veins. The patient had a history of severe head trauma that had occurred 30 years earlier. This is the first case report in which a previous head trauma is strongly believed to be the cause of an anterior cranial fossa dural AVM. The authors postulate that anterior cranial fossa dural AVMs can develop secondary to a head trauma.     

Anatomic considerations of anterior transarticular screw fixation for atlantoaxial instability

STUDY DESIGN: Anatomic parameters of C1 and C2 were measured in 30 dried human cervical spines. Anterior transarticular C1-C2 screws were placed in 15 cadaveric spines. OBJECTIVE: To provide anatomic data for anterior transarticular atlantoaxial screw or C1-C2 screw and plate fixation. SUMMARY OF BACKGROUND DATA: A posterior approach to fixation in the atlantoaxial joint has been well described. Damage to the vertebral artery is documented as a rare complication of posterior atlantoaxial transarticular screw fixation. An anterior surgical approach to exposing the upper cervical spine for internal fixation and bone graft recently has been developed. No anatomic information regarding the anterior transarticular atlantoaxial screw or screw and plate fixation between C1 and C2 is available in the literature. METHODS: Direct measurements using digital calipers and a goniometer were taken from 30 pairs of dried human C1 and C2 vertebrae. The anterior transarticular C1-C2 screw insertion point is at the junction of the lateral edge of the C2 vertebral body to 4 mm above the inferior edge of the C2 anterior arch. The parameters related to anterior transarticular atlantoaxial screw fixation or screw and plate fixation between the C1 lateral mass and the C2 vertebral body were measured. Fifteen embalmed cadavers were used for anterior C1-C2 transarticular screw placement. Longer screws (30-40 mm) were used to detect whether the screw tips violated the upper cervical canal or vertebral arteries. RESULTS: In the anterior transarticular atlantoaxial screw placement, lateral angulation of the screw placement relative to sagittal plane ranged from 4.8 +/- 1.8 degrees to 25.3 +/- 2.6 degrees. The posterior angulation of the screw placement relative to the coronal plane ranged from 12.8 +/- 3.1 degrees to 22.6 +/- 3.2 degrees. The length of the medial screw path ranged from 14.7 +/- 1.5 mm to 25.4 +/- 2.8 mm. In the anterior screw and plate fixation, the anteroposterior diameter of the inferior facet articular surface ranged from 16.2 +/- 1.6 mm to 17.1 +/- 1.8 mm. The anteroposterior diameter of the C2 vertebral body ranged from 9.3 +/- 1 mm to 16.2 +/- 1.8 mm. The anterior prevascular retropharyngeal approach appropriately exposed the atlantoaxial joint for anterior transarticular C1-C2 screw placement. No screws violated the vertebral artery and cervical canal. CONCLUSIONS: An anterior transarticular atlantoaxial screw 15-25 mm long can be inserted with a lateral angulation of 5-25 degrees relative to the sagittal plane and a posterior angulation of 10-25 degrees relative to the coronal plane. Additionally, in C1-C2 anterior plate fixation screws 15 mm long could be anchored in the inferior facet of the C1, and screws 9-15 mm long could be anchored in the C2 vertebral body.     

Metopic synostosis: in favour of a "simplified" surgical treatment

Metopic synostosis is a relatively simple form of craniosynostosis, resulting from premature fusion of the metopic suture. In this pathology different degrees of dysmorphia of the anterior cranial fossa and the presence of associated anomalies of the skull might enable specific subgroups to be identified. Since most functional and cosmetic anomalies benefit from early surgical treatment, over the last few years neurosurgeons have been forced to elaborate less drastic, but nonetheless effective, surgical techniques. In the present report we analyze the surgical results obtained in a series of 62 infants with trigonocephaly operated on within their 1st year of life. Patients were subdivided into two groups (group I: 8 patients; group II: 54 patients) according to the specific dysmorphic characteristics of the frontal bone and anterior cranial fossa, and the presence of compensatory deformities affecting the anterior cranial base and temporo-parietal region. All the patients were treated using one of two relatively simple surgical techniques (procedure A: inversion of two hemifrontal bone flaps--48 cases; procedure B: the "shell" operation--14 cases). Both surgical procedures appeared to be effective, allowing adequate functional and cosmetic correction of the cranial deformity. In patients operated on following procedure B surgical time and blood loss were dramatically reduced. Long-term outcomes were satisfactory in all cases, irrespective of the surgical technique used. In the group II patients, however, progressive normalization of the interorbital distance was constantly observed, suggesting a different degree of stenotic involvement at the level of the anterior cranial base in these patients.     

Anatomic relations of the thoracic pedicle to the adjacent neural structures

STUDY DESIGN: This study analyzed anatomic parameters between the thoracic pedicles and the spinal nerve roots. OBJECTIVES: To quantitatively determine the anatomic relations of the thoracic pedicle to the adjacent neural structures. SUMMARY OF BACKGROUND DATA: Pedicular screw placement carries with it potential hazard to the surrounding neural structures, especially in the thoracic spine. No studies exist regarding the anatomic relations of the thoracic pedicle to the adjacent nerve roots. METHODS: Fifteen cadavers were obtained for study of the thoracic spine. All soft tissue was dissected off the thoracic spine. Laminectomy and total removal of the superior and inferior articular facets was then performed on C7-T1 through T12-L1 to expose the pedicles, nerve roots, and dura. Measurements were taken from the pedicle to the nerve root superiorly and inferiorly as well as between the pedicles. Also, the superoinferior diameter of the nerve root and the frontal angle of the nerve root were measured. Symmetrical structures were measured bilaterally. RESULTS: The results showed that no epidural space could be found between the dural sac and the pedicle in all 15 cadavers. The average distances from the thoracic pedicle to the adjacent nerve roots superiorly or inferiorly at all levels ranged from 1.9 to 3.9 mm and from 1.7 to 2.8 mm, with a minimum of 1.3 mm, respectively. The interpedicular distance increased from T1 (13.8 mm) to T3, slightly decreased in T4-T5, then gradually increased to T12 (16.6 mm). The superoinferior diameter of the nerve root increased consistently from 2.9 mm at T1 to 4.6 mm at T11. The frontal nerve root angle decreased consistently from T1 (120.1 degrees) to T12 (57.1 degrees), except at T4-T5. CONCLUSIONS: This study suggested that more care be taken into consideration in placing a transpedicular screw in the transverse plane than in placing a screw in the sagittal plane in the thoracic spine.     

A study of the concentration of orally administered sparfloxacin found in exudates from suture wounds beneath occlusive dressings

We have developed a simple algorithm for scalp localization for craniotomy. Using a series of CT/MRI data, the point on the scalp closest to the center of the lesion (T) is determined by our program. A plane (plane R) is defined by three points: bilateral auditory meati and T. Point S is the intersection of three planes: the plane R, the scalp surface and the midsagittal plane. The distance from either S or the ipsilateral external auditory meatus to T is measured along the scalp surface on the plane R. The distance from the nasion to S along the scalp surface on the midsagittal plane is also measured. To determine the craniotomy site, these distances are measured directly on a patient's scalp in the operating room. This simple and accurate method for scalp localization could be used by installing our program in conventional CT/MR scanners.     

Tumor necrosis factor alpha and interleukin 6 release induced by antibiotic killing of Pseudomonas aeruginosa and Staphylococcus aureus

OBJECTIVE: The purpose of this study was to determine the depth that implants may be safely placed into the distal femoral epiphysis (DFE) for the repair of distal femoral physeal fractures. STUDY DESIGN: The depth of the DFE was related to the radiographic thickness of the patella in this experimental study. ANIMALS OR SAMPLE POPULATION: Twenty immature canine cadavers. METHODS: Patella thicknesses were measured from lateral radiographs. Actual DFE depths were determined for pins driven in normograde fashion and for pins driven retrograde from the central depression between the metaphyseal pegs and from the cranial pegs. The association of DFE depth and patella thickness was evaluated using linear regression analysis. Using 95% confidence intervals, rules for estimating the safe depth of implant placement into the DFE were determined. RESULTS: DFE depth had significant correlation with patella thickness for pins placed in retrograde fashion from the central depression between the metaphyseal pegs (r2 = .83) and from the cranial pegs (r2 = .82) and for pins placed in normograde fashion (r2 = .65). CONCLUSIONS: Based on 95% confidence intervals, pins placed in retrograde fashion from the central depression between the metaphyseal pegs may be safely driven into the DFE a distance equal to 140% of patella thickness. Pins placed from the cranial metaphyseal pegs may be driven to a depth equal to 80% of patella thickness, and pins placed in normograde fashion may be driven to a depth equal to 30% of patella thickness. CLINICAL RELEVANCE: Measurement of patella thickness assists the surgeon in determining the approximate depth that pins may be driven into the DFE without penetrating the articular surface of the stifle joint.     

A new reconstruction of the Le Moustier 1 skull and investigation of internal structures using 3-D-muCT data

Using the non-destructive technique of 3-D micro computed tomography (3-D-microCT), we present a new, virtual reconstruction of the Le Moustier 1 Neandertal skull. This new reconstruction corrects defects found in earlier reconstruction attempts by repositioning misaligned cranial fragments, addressing the problem of asymmetry caused by pressure during the fossilization process, and placing the basioccipital in its proper anatomical position. Metric comparisons between Le Moustier 1 and juvenile and adult Neandertals demonstrate that facial height proceeded at a faster rate of growth than facial prognathism at the beginning of the adolescent period. They also confirm the anterior placement of the basioccipital. A compound painted to match the colour of the fossilized bone was used in previous reconstruction attempts and the aim of this analysis was to remove the false material to reveal to what extent the fossilized bone was preserved. The areas with the most artificial material and glue include the palate, areas around the mandibular teeth, the left frontal, and parts of the right parietal and temporal bones. The microCT data were also used to examine internal structures of the skull including the frontal sinus and the labyrinth of the inner ear. An investigation of the frontal sinus reveals morphology similar to that found in adult Neandertals, although the structure does not extend to mid-orbit. The dimension of the radius of curvature of the lateral semicircular canal falls within one standard deviation, and the anterior and posterior canals within two standard deviations, of the published Neandertal mean. As in other Neandertals, the posterior semicircular canal is in an inferior position relative to the plane of the lateral canal.     

Breaking strength retention and histologic effects around 1.3-mm. ORTHOSORB polydioxanone absorbable pins at various sites in the rabbit

Absorbable 1.3-mm polydioxanone (ORTHOSORB) pins were implanted in 75 New Zealand White rabbits in three sites: within the lateral subcutaneous tissue parallel to the femur, down the femoral intramedullary canal, and mediolaterally across the femoral condyles (transcondylar). Pins were harvested at periodic intervals up to 56 and 365 days for mechanical and histologic analyses, respectively. Mechanical analyses were performed by loading the pin in double shear. Histologic analyses were performed on the pin and surrounding tissue. Histologic observations revealed a typical nonspecific foreign-body reaction at all implant sites that resolved at 1 year after resorption of the pin. On histologic examination, there was complete resorption of the pin material in the subcutaneous site by day 182, and there was complete resolution of all response to the pin in six of nine rabbits by day 365. In the intramedullary site, pin material was completely resorbed, based on histologic examination, in five of six rabbits by day 182, and there was complete resolution of the response to the pin in eight of nine rabbits by day 365. The pin material was completely resorbed based on histologic examination of the transcondylar site by day 210, and there was complete resolution of the response to the pin in four of six rabbits by day 270 and in four of nine rabbits by day 365. No enlarged pin tracks or sinus formations were observed in or near the implants sites. The average initial shear strength as 171.4+/ 5.1 MPa, and the breaking strength retention decreased with increasing implantation time. Pins from the subcutaneous regions maintained above 97% of their initial strengths at 28 days, and those from the intramedullary canals maintained above 92%. At later times the strength of the pins implanted in the intramedullary canal decreased more rapidly than those from the subcutaneous region. Overall, the average breaking strength of the subcutaneous pins was significantly greater than that of the intramedullary pins at all time points beyond 14 days. These data indicate that the pins exhibited a strength retention profile sufficient to allow normal healing of bone without enlarged pin tracts, allergic reactions, or sinus formations.     

Molecular genotyping of Staphylococcus aureus strains: comparison of repetitive element sequence-based PCR with various typing methods and isolation of a novel epidemicity marker

OBJECTIVE: To detail the characteristics and management of rarely reported and incompletely described dermoid cysts originating in the temporal fossa. DESIGN: Retrospective case series. PARTICIPANTS: Five patients ranging from 2 to 38 years of age with a mass in the temporal region (posterior to the lateral orbital rim) participated. INTERVENTION: Computed tomography (CT) and excisional biopsy were performed. MAIN OUTCOME MEASURES: Clinical and CT characteristics and surgical outcomes were measured. RESULTS: Computed tomography showed cystic lesions, originating from the region anterior to the confluence of the greater wing of the sphenoid, frontal, and zygomatic bones. Displacement of the anteriormost portion of the temporalis muscle was common. Three cysts were isolated to the temporalis fossa, while two showed more extensive bony erosion and extension into the cranial and orbit cavities. At surgical excision, gross rupture of the cysts was noted in two cases, and two were completely liquefied. Histopathology showed variable inflammation surrounding all of the dermoid cysts. All patients did well after surgery. CONCLUSIONS: Dermoid cysts may infrequently occur "primarily" in the temporal fossa. Bone involvement and anterior temporalis muscle displacement are common. An origin from the area anterior to the confluence of the greater wing of the sphenoid, frontal, and zygomatic bones is seen. A coronal approach facilitates wide exposure and excision. When dural extension is suggested on CT, neurosurgical assistance may be required.     

Midline cerebral morphometry distinguishes frontotemporal dementia and Alzheimer's disease

We investigated and contrasted midline cerebral structures in frontotemporal dementia (FTD) and Alzheimer's disease (AD). FTD and AD may be difficult to distinguish clinically. FTD typically affects frontal and anterior temporal regions, whereas AD tends to involve more posterior temporal and parietal areas. We hypothesized that disease-specific cerebral alterations would be differentially reflected in corresponding regions of the corpus callosum (CC), pericallosal CSF space (PCS), or their ratio (CC:PCS). Regions-of-interest (ROIs) from midsagittal MRIs in 17 AD, 16 FTD, and 12 elderly control (EC) subjects were analyzed. ROIs were divided into four regions using an anatomic landmark-based computer algorithm and were adjusted for head size variation. FTD subjects had a much smaller anterior CC region and significantly larger PCS area, particularly in anterior regions. AD and EC subjects did not differ significantly in any total or regional ROI measure. Total and anterior CC:PCS ratios were markedly lower in FTD patients. Across groups, total CC:PCS correlated significantly with midsagittal cerebral area and was similarly associated with Mini-Mental State Examination score. Anterior CC (AD) and PCS (FTD) regions exhibited disease-specific relationships to these variables. A discriminant model using two ROI variables correctly classified 91% of AD and FTD patients, comparing favorably with blind clinical MRI diagnostic ratings. Midline cerebral structural alterations reflect differential patterns of cerebral degeneration in AD and FTD, yielding morphometric indices that may facilitate the study of brain-behavior relationships and differential diagnosis of dementia.     

The superior orbital fissure: a microanatomical study

The superior orbital fissure (SOF) is a small (3 x 22 mm), but functionally very important, region. The microsurgical anatomy of the SOF was studied on five adult, formalin-fixed cadavers. The vascular structures of three of them were injected with latex. The SOF contains the third, fourth, and sixth nerves, the ophthalmic branch of the fifth nerve, and the superior orbital vein. It is divided by the two tendons of the lateral rectus muscle: the superior part contains the fourth nerve, the frontal and the lacrimal branches of the ophthalmic division of the fifth nerve, and the superior orbital vein; the inferior part contains the superior and inferior branches of the third, the nasociliary, and the sixth nerves. In regard to surgical access to lesions involving the SOF, the question is often raised as to whether the dissection should be started from the cranial or the orbital side. The following procedure is recommended: 1) frontotemporo-orbital craniotomy; 2) resection of the lesser wing of the sphenoid bone, of the anterior clinoid, and of the superolateral part of the orbital roof and opening of the dura along the Sylvian fissure, with an extension to the frontal lobe and another extension to the temporal lobe; 3) incision of the periorbita in its superolateral part and identification of the frontal nerve; and 4) dissection of the frontal nerve in an anteroposterior direction. The fourth nerve will be found medially and inferiorly to the frontal nerve. The third nerve will be found inferomedially to the frontal nerve in the SOF, and the sixth nerve will be found inferiorly to the inferior branch of the third nerve.     

Percutaneous pinning of proximal humerus fractures: a biomechanical study

Mechanical testing of two-part surgical neck fractures fixed with four different pin configurations was performed. Ten fresh, frozen, unembalmed humeri stripped of all soft tissues were used; the surgical neck was osteotomized perpendicular to the humerus long axis. Terminally threaded 2.5-mm AO pins were used to fix the fracture. Humeri then were tested in both torsion and bending on a custom-made jig using Instron 1331 to assess the rigidity of pinning constructs. In torsion, two lateral pin construct was significantly less rigid than all other pin configurations. The addition of an anterior pin to two lateral pins did not increase bending rigidity, but significantly increased torsional stiffness. The addition of two bicortical tuberosity pins or two bicortical tuberosity pins and one anterior pin to two lateral pins significantly increased rotational and bending rigidity. Results confirm clinical data, and the authors conclude that multiplanar pins are needed to augment torsional stiffness, and that the addition of two bicortical tuberosity pins enhances bending rigidity.     

A comparative evaluation of halo pin designs in an immature skull model

To design an improved halo pin for use in pediatric patients, three commonly used halo pins were evaluated with a mechanical testing apparatus and segments of prepared fetal calf skull. The pins were driven through the bone segments while the load at the bone-pin interface was measured. New pins were designed with respect to pin tip and flange width and similarly compared. Mean maximum loads to penetration, normalized for bone segment thickness, were 55.6 N/mm for the PMT Corporation pin, 61.5 N/mm for the Bremer pin, and 73.6 N/mm for the Ace pin. Four new, short tipped pins were designed and compared with the Ace pin, and there was no significant difference. Finally, four new pins were designed with varying flange widths. Mean maximum loads, normalized for bone segment thickness, were 68.9 N/mm for the 4.2 mm flange, 72.2 N/mm for the 4.7 mm flange, 92.9 N/mm for the 5.2 mm flange, and 96.4 N/mm for the 5.7 mm flange. The findings of this investigation are clinically important because they may help to explain the variability in the complication rates seen with the use of different halo systems in children. The three halo pins currently on the market have different pin designs, including tip lengths and flange distances, which contribute to the difference in load to penetration for each pin. The new, wide flanged, short tipped halo pin design might decrease the complication rate of halo use in children by providing an improved capacity to resist penetration despite increased loads of application.     

Intrapartum fetal oxygen saturation monitoring in congenital fetal heart block

Precutaneous Kirschner wire fixation of displaced Gartlands types II and III supracondylar fractures with image guidance remains a preferred procedure for most orthopaedic units. Various K-wire configurations have been in use, but recent objective evaluation of pin stability has favoured two techniques; the 2 crossed pins placed from the medial and lateral epicondyles, and 2 parallel lateral pins when the former technique is impracticable because of swelling. We reviewed patients who had K-wire fixation precutaneously over a 2-year period (Feb 1996 to Feb 1998). There were 44 children, 30 males, 14 females, ages between 1-15 years. 19 patients had (medial and lateral pins) 15, (2 parallel lateral) and 10 patients (2 lateral crossed) precutaneous pin placement respectively. Their postoperative course indicated that maximum stability was obtained with two opposite crossed pins, followed by the 2 paralleled pin method. These observation determined the choice of technique by the surgeons who operated on these patients.     

Surgical anatomy of the infratemporal fossa: the styloid diaphragm revisited

INTRODUCTION: The infratemporal fossa (ITF) gives passage to most major cerebral vessels and cranial nerves. Dissection of the ITF is essential in many of the lateral cranial base approaches and in exposure of the high cervical internal carotid artery (ICA). We reviewed the surgical anatomy of this region. METHODS: Direct foraminal measurements were made in seven dry skulls (14 sides), and the relationship of these foramina to each other and various landmarks were determined. Ten ITF dissections were performed using a preauricular subtemporal-infratemporal approach. Preliminary dissections of the extracranial great vessels and structures larger than 1 cm were performed using standard macroscopic surgical techniques. Dissection of all structures less than 1 cm was conducted using microsurgical techniques and instruments, including the operating microscope. The anatomic relationships of the muscles, nerves, arteries, and veins were carefully recorded, with special emphasis regarding the relationship of these structures to the styloid diaphragm. The dissection was purely extradural. RESULTS: The styloid diaphragm was identified in all specimens. It divides the ITF into the prestyloid region and the retrostyloid region. The prestyloid region contains the parotid gland and associated structures, including the facial nerve and external carotid artery. The retrostyloid region contains major vascular structures (ICA, internal jugular vein) and the initial exocranial portion of the lower Cranial Nerves IX through XII. Landmarks were identified for the different cranial nerves. The bifurcation of the main trunk of the facial nerve was an average of 21 mm medial to the cartilaginous pointer and an average of 31 mm medial to the tragus of the ear. The glossopharyngeal nerve was found posterior and lateral to stylopharyngeus muscle in nine cases and medial in only one. The vagus nerve was consistently found in the angle formed posteriorly by the ICA and the internal jugular vein. The spinal accessory nerve crossed anterior to the internal jugular vein in five cases and posterior in another five cases. It could be located as it entered the medial surface of the sternocleidomastoid muscle 28 mm (mean) below the mastoid tip. The hypoglossal nerve was most consistently identified as it crossed under the sternocleidomastoid branch of the occipital artery 25 mm posterior to the angle of the mandible and 52 mm anterior and inferior to the mastoid tip. CONCLUSION: The styloid diaphragm divides the ITF into prestyloid and retrostyloid regions and covers the high cervical ICA. Using landmarks for the exocranial portion of the lower cranial nerves is useful it identifying them and avoiding injury during approaches to the high cervical ICA, the upper cervical spine, and the ITF.     

Unusual approaches to hypophyseal adenomas

For pituitary adenomas surgery, rhinoseptal transsphenoidal approach is used in 98 to 99% of the cases. Although this approach is fitting for microadenomas and the majority of macroadenomas, some of them develop extensions in the nasal fossas, the posterior cranial fossa, the suprasellar region, or into the cavernous sinus and will require other approaches. For the superior routes, the frontopterional approach gives good control of the suprasellar region, the anterior and middle base of the skull. The tumor dissection is performed inside the concavity of the chiasm and between the internal carotid artery and the optic nerve (optico-carotid approach). The frontopterional approach is used for superolateral extensions, especially in the lateral fissure. The bifrontal basal inter hemispheric approach, through a medial frontal bone flap tangential to the base, gives a good route to the suprasellar region and behind the dorsum, and also for tumors extended in the third ventricle in case of prefixed chiasm. For the inferior routes, the participation of ENT or craniofacial surgeons is a great help. The transfacial or transethmoidal approach performs a hollowing of the nasal fossas and gives a large interorbital tunnel adapted for tumors extended in the rhinopharynx and the ethmoid. The Le Fort I maxillary osteotomy offers also a large approach for adenomas extending in the rhinopharynx. The transcavernous approach from Dolenc, for adenomas progressing in the cavernous sinus requires a long and difficult procedure. The progression of some adenomas in many directions may require a combined approach in one or two procedures.     

Sphenoethmoidal mucoceles with intracranial extension--three case reports

Three unusual cases of sphenoethmoidal mucoceles with rare intracranial extension are reported. A 64-year-old female presented with a 7-month history of right visual disturbance. Computed tomography (CT) and magnetic resonance (MR) imaging demonstrated a huge mass in the right middle fossa. She underwent right frontotemporal craniotomy. Postoperatively, her proptosis and cranial nerve dysfunction had improved markedly. A 53-year-old female complained of headache, nausea, and dizziness. CT and MR imaging revealed a cystic mass filling the right sphenoid sinus. The cystic lesion was evacuated through the transnasal approach. She was doing well postoperatively and has been asymptomatic. A 39-year-old male complained of headache, vomiting, and right visual disturbance. CT and MR imaging demonstrated a homogeneous mass occupying the sphenoid sinus. Sphenoidotomy exposed the cyst extending superiorly into the anterior cranial fossa. He recovered from the visual disturbances and has been asymptomatic since. MR imaging provides confirmation of the diagnosis of sphenoethmoidal mucocele and is important for preoperative evaluation.     

The reliability of the lateral radiograph in determination of the optimal transarticular C1-C2 screw length

STUDY DESIGN: This study assessed the value of using lateral radiographs in evaluating the optimal screw length in transarticular C1-C2 screw fixation. OBJECTIVES: To assess the reliability of the lateral radiograph in determining the optimal transarticular C1-C2 screw length. SUMMARY OF BACKGROUND DATA: Transarticular C1-C2 screw placement is usually performed using anatomic landmarks and fluoroscopy. A lateral fluoroscopic image is valuable when directing screws in the sagittal plane, but its exact role in determining screw length has not been investigated. METHODS: Eight cervical spine specimens were used in this study. Screw placements were performed in each specimen, fixed in the exact lateral position and under direct visualization. After each placement, a lateral radiograph was taken. The odontoid process was divided into three equal portions. Another portion anterior to the odontoid process was called the anterior tubercle region. The number of screw tips appearing in each portion on the radiograph was then recorded for each placement. In addition, 30 C1 specimens were measured to evaluate the anterior part of C1. RESULTS: The results showed that 12.5% of the screws placed 2 mm short of reaching the ventral cortex and 0 mm overpenetrating the ventral cortex of the lateral mass of C1 projected in the radiograph on the anterior tubercle region, 37.5% on the anterior region of the odontoid process, and 50% on the middle region of the odontoid process. Twenty-five percent of the screws that were placed to overpenetrate, by 2 or 4 mm, the ventral cortex of the lateral mass of C1 were projected on the anterior tubercle region in the radiograph, and 50% and 62.5% were projected on the anterior region of the odontoid process, respectively. The mean vertical distance between the anteriormost point of the anterior tubercle of the anterior ring and the middle of the ventral cortex of the lateral in all specimens was 5.6 +/- 1 mm, and the mean transverse angle of the anterior ring relative to the frontal plane was 21.1 +/- 3.5 degrees. CONCLUSIONS: This results in this study indicate that a lateral radiograph may not be reliable in determining the optimal screw length, although it is valuable in directing accurate screw angle in the sagittal plane. Preoperative computed tomographic evaluation of the C1-C2 region may be helpful in estimating the location of the screw tip on the lateral radiograph during surgery.     

Anterior and middle cranial fossa in traumatic brain injury: Relevant neuroanatomy and neuropathology in the study of neuropsychological outcome.

The frontal and temporal lobe regions of the brain have a high vulnerability to injury as a consequence of cerebral trauma. One reason for this selective vulnerability is how the frontal and temporal regions are situated in the anterior and cranial fossa of the skull. These concavities of the skull base cup the frontal and temporal lobes which create surface areas of contact between the dura, brain, and skull where mechanical deformation injures the brain. In particular, the sphenoid ridge and the free-edge of the tentorium cerebelli are uniquely situated to facilitate injury to the posterior base of the frontal lobe and the anterior pole and medial surface area of the temporal lobe. Three-dimensional image reconstruction with computerized tomography and magnetic resonance imaging are used to demonstrate the vulnerability of these regions. How neuropsychological deficits result from damage to these areas is reviewed and discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)