Showing papers on "Skull published in 2010"

How to choose? Endoscopic skull base reconstructive options and limitations.

Abstract: As endoscopic skull base resections have advanced, appropriate reconstruction has become paramount. The reconstructive options for the skull base include both avascular and vascular grafts. We review these and provide an algorithm for endoscopic skull base reconstruction. One hundred and sixty-six skull base dural defects, reconstructed with an endonasal vascular flap, were examined. As an adjunct, avascular reconstruction techniques are discussed to illustrate all options for endonasal skull base reconstruction. Cerebrospinal fluid (CSF) leak rates are also discussed. Small CSF leaks may be successfully repaired with various avascular grafting techniques. Endoscopic endonasal approaches (EEAs) to the skull base often have larger dural defects with high-flow CSF leaks. Success rates for some EEA procedures utilizing avascular grafts approach 90%, yet in high-flow leak situations, success rates are much lower (50 to 70%). Defect location and complexity guides vascularized flap choice. When nasoseptal flaps are unavailable, anterior/sellar defects are best managed with an endoscopically harvested pericranial flap, whereas clival/posterior defects may be reconstructed with an inferior turbinate or temporoparietal flap. An endonasal skull base reconstruction algorithm was constructed and points to increased use of various vascularized reconstructions for more complex skull base defects.

Pericranial flap for endoscopic anterior skull-base reconstruction: clinical outcomes and radioanatomic analysis of preoperative planning.

Abstract: Background One of the major challenges of cranial base surgery is reconstruction of the dural defect and prevention of postoperative cerebrospinal fluid (CSF) fistula. The introduction of endoscopic techniques and an endonasal approach to the ventral skull base has created new challenges for reconstruction. Objective We have developed an endoscopic pericranial flap (PCF) for skull base reconstruction and hereby present the initial cohort of patients who had endonasal reconstruction with a PCF after endoscopic skull base resection. We also demonstrate a method to radiographically incorporate anticipated skull base defects for preoperative planning of PCF length. Methods Dural defects after endonasal skull base resection of invasive tumors were reconstructed with an onlay PCF (n = 10). We performed radiological studies to assist preoperative planning for where to make incisions while harvesting a PCF for anterior skull base, sellar, and clival defects. Results Each of the 10 patients had excellent healing of their skull base and had no evidence of any postoperative cerebrospinal fluid leaks. Eight patients had radiation therapy without flap complications. Radiographic studies demonstrate that the adequate PCF length, covering defects of the anterior skull base, sellar, and clival defects are 11.31 to 12.44 cm, 14.31 to 15.57 cm, and 18.5 to 20.42 cm, respectively. Conclusion The PCF provides an option for endonasal reconstruction of cranial base defects and can be harvested endoscopically. Pre-operative radiographic evaluation may guide surgical planning. There is minimal donor site morbidity, and the flap provides enough surface area to cover the entire ventral skull base.

Anatomical considerations for endoscopic endonasal skull base surgery in pediatric patients.

Abstract: Objectives/Hypothesis: Pediatric skull base surgery is limited by several boney sinonasal landmarks that must be overcome prior to tumor dissection. When approaching a sellar or parasellar tumor, the piriform aperture, sphenoid sinus pneumatization, and intercarotid distances are areas of potential limitation. Quantitative pediatric anatomical measurements relevant to skull base approaches are lacking. Our goal was to use radio-anatomic analysis of computed tomography scans to determine anatomical limitations for trans-sphenoidal approaches in pediatric skull base surgery. Study Design: A radio-anatomic cross-sectional survey. Methods: Measurements included the diameter of the piriform aperture, posterior extent of sphenoid sinus pneumatization, and intercarotid distances on fine-cut, age-stratified maxillofacial scans. Fifty pediatric (<18 years of age) and 10 adult patients were equally subdivided into seven age groups and compared to determine age-related differences in sphenoid sinus pneumatization, skull base thicknesses, and intercarotid distances. Results: Piriform aperture width was significantly greater in adults than in patients under age 7 years (P ≤ .002). Three fourths of the planum and sellar face and one half of the sellar floor were pneumatized by ages 6 to 7 years. Superior clival pneumatization was not evident until 12 years of age. Clival intercarotid distances were not different among groups. Drilling distances for trans-planar, trans-sellar, and trans-clival approaches are described. Conclusions: Several potential anatomic limits must be considered in pediatric skull base surgery, and these vary according to age. Piriform aperture is likely a limit only in the youngest patients (under 2 years). Sphenoid pneumatization to the planum and sella start at 3 years and complete by age 10 years. Clival intercarotid distances do not change significantly and are not prohibitively narrow in any age group. Laryngoscope, 2010

Human Induced Rotation and Reorganization of the Brain of Domestic Dogs

Abstract: Domestic dogs exhibit an extraordinary degree of morphological diversity. Such breed-to-breed variability applies equally to the canine skull, however little is known about whether this translates to systematic differences in cerebral organization. By looking at the paramedian sagittal magnetic resonance image slice of canine brains across a range of animals with different skull shapes (N = 13), we found that the relative reduction in skull length compared to width (measured by Cephalic Index) was significantly correlated to a progressive ventral pitching of the primary longitudinal brain axis (r = 0.83), as well as with a ventral shift in the position of the olfactory lobe (r = 0.81). Furthermore, these findings were independent of estimated brain size or body weight. Since brachycephaly has arisen from generations of highly selective breeding, this study suggests that the remarkable diversity in domesticated dogs' body shape and size appears to also have led to human-induced adaptations in the organization of the canine brain.

Diagnostic Radiology and Ultrasonography of the Dog and Cat

Abstract: THE RADIOGRAPH Density and Opacity Contrast Radiologic Changes Standard Views Contrast Media Viewing the Radiograph Ultrasound THE ABDOMEN The Abdominal Cavity The Liver The Gallbladder The Spleen The Pancreas The Esophagus The Stomach The Small Intestine The Large Intestine The Urinary System Kidneys and Ureters The Ureters The Bladder The Urethra The Male Genital Tract The Penis The Prostate Gland The Female Genital Tract The Uterus The Ovaries The Vagina The Mammary Gland THE THORAX The Intrathoracic Structures The Pharynx, Larynx and Hyoid Apparatus The Trachea The Bronchi The Lungs The Diaphragm The Pleurae The Mediastinum The Thoracic Wall The Spine The Ribs The Sternum The Skin Lymph Nodes The Cardiovascular System BONES AND JOINTS Bones Joints Conditions Affecting Bones and Joints THE SKULL AND VERTEBRAL COLUMN The Skull The Nasal Chambers The Paranasal Sinuses The Auditory System The Teeth The Salivary Glands The Nasolacrimal Ducts The Brain The Eye The Vertebral Column SOFT TISSUES Calcification Arteriovenous Fistula Fascial Planes Soft Tissue Pathology Cervical Soft Tissue Thyroid Gland Muscles The Adrenal Glands Lymph Nodes INDEX

Mechanical analysis of feeding behavior in the extinct "terror bird" Andalgalornis steulleti (Gruiformes: Phorusrhacidae).

Abstract: The South American phorusrhacid bird radiation comprised at least 18 species of small to gigantic terrestrial predators for which there are no close modern analogs. Here we perform functional analyses of the skull of the medium-sized (∼40 kg) patagornithine phorusrhacid Andalgalornis steulleti (upper Miocene–lower Pliocene, Andalgala Formation, Catamarca, Argentina) to assess its mechanical performance in a comparative context. Based on computed tomographic (CT) scanning and morphological analysis, the skull of Andalgalornis steulleti is interpreted as showing features reflecting loss of intracranial immobility. Discrete anatomical attributes permitting such cranial kinesis are widespread phorusrhacids outgroups, but this is the first clear evidence of loss of cranial kinesis in a gruiform bird and may be among the best documented cases among all birds. This apomorphic loss is interpreted as an adaptation for enhanced craniofacial rigidity, particularly with regard to sagittal loading. We apply a Finite Element approach to a three-dimensional (3D) model of the skull. Based on regression analysis we estimate the bite force of Andalgalornis at the bill tip to be 133 N. Relative to results obtained from Finite Element Analysis of one of its closest living relatives (seriema) and a large predatory bird (eagle), the phorusrhacid's skull shows relatively high stress under lateral loadings, but low stress where force is applied dorsoventrally (sagittally) and in “pullback” simulations. Given the relative weakness of the skull mediolaterally, it seems unlikely that Andalgalornis engaged in potentially risky behaviors that involved subduing large, struggling prey with its beak. We suggest that it either consumed smaller prey that could be killed and consumed more safely (e.g., swallowed whole) or that it used multiple well-targeted sagittal strikes with the beak in a repetitive attack-and-retreat strategy.

Skull fracture vs. accessory sutures: how can we tell the difference?

Abstract: Plain film radiography remains the most cost effective method in evaluating skull fractures and can easily differentiate major sutures and common vascular grooves from fractures. However, in children this can be complicated due to the presence of numerous synchondroses and unusual accessory sutures. Plain film evaluation is especially challenging not only because of various artifacts that can degrade the study but also the inability to visualize intracranial processes, such as contusions and hemorrhage, that can substantiate a calvarial finding. Minimal soft tissue swelling can be difficult to see even with oblique views. Superimposition of normal suture lines like the metopic suture can mimic a fracture if one is not careful to obtain additional views [1]. During the past decade, the increasing use of spiral and multidetector CT have lead to the ability of workstations to generate three-dimensional (3D) reconstructions of the skull. Therefore if cranial CT is deemed clinically necessary in trauma patients, questionable fractures can be confidently differentiated from unusual accessory sutures using these additional workstation capabilities.

Ontogenetic variation in the bony labyrinth of Monodelphis domestica (Mammalia: Marsupialia) following ossification of the inner ear cavities.

Abstract: Ontogeny, or the development of an individual from conception to death, is a major source of variation in vertebrate morphology. All anatomical systems are affected by ontogeny, and knowledge of the ontogenetic history of these systems is important to understand when formulating biological interpretations of evolutionary history and physiology. The present study is focused on how variation affects the bony labyrinth across a growth series of an extant mammal after ossification of the inner ear chambers. Digital endocasts of the bony labyrinth were constructed using CT data across an ontogenetic sequence of Monodelphis domestica, an important experimental animal. Various aspects of the labyrinth were measured, including angles between the semicircular canals, number of turns of the cochlea, volumes of inner ear constituents, as well as linear dimensions of semicircular canals. There is a strong correlation between skull length and age, but from 27 days after birth onward, there is no correlation with age among most of the inner ear measurements. Exceptions are the height of the arc of the lateral semicircular canal, the angular deviation of the lateral canal from planarity, the length of the slender portion of the posterior semicircular canal, and the length of the canaliculus cochleae. Adult dimensions of several of the inner ear structures, such as the arcs of the semicircular canals, are achieved before the inner ear is functional, and the non-ontogenetic variation in the bony labyrinth serves as an important source for behavioral, physiological, and possibly phylogenetic information.

Transcondylar fossa (supracondylar transjugular tubercle) approach: anatomic basis for the approach, surgical procedures, and surgical experience.

Abstract: The authors clarify the anatomic basis and the usefulness of the transcondylar fossa approach (T-C-F A), in which the posterior portion of the jugular tubercle is removed extradurally through the condylar fossa with the atlanto-occipital joint intact. The authors first performed an anatomic study to identify the area to be removed using cadaveric specimens and then applied the T-C-F A to foramen magnum surgeries. The surgeries included clipping a vertebral artery-posterior inferior cerebellar artery aneurysm in 11 cases, microvascular decompression for glossopharyngeal neuralgia in 15 cases, and removing intradural foramen magnum tumors in 17 cases. Only the condylar fossa was removed, but the approach offered very good visualization of the lateral part of the foramen magnum and sufficient working space. These surgeries were performed safely without major complications. This skull base approach is minimally invasive and is not difficult. Therefore, it can be a standard approach for accessing intradural lesions of the foramen magnum. It can be combined with the transcerebellomedullary fissure approach from the lateral side and can also be easily changed to the transcondylar approach, if necessary.

Beyond the closed suture in apert syndrome mouse models: Evidence of primary effects of FGFR2 signaling on facial shape at birth

Abstract: Apert syndrome is a congenital disorder caused mainly by two neighboring mutations on fibroblast growth factor receptor 2 (FGFR2). Premature closure of the coronal suture is commonly considered the identifying and primary defect triggering or preceding the additional cranial malformations of Apert phenotype. Here we use two transgenic mouse models of Apert syndrome, Fgfr2+/S252W and Fgfr2+/P253R, to explore variation in cranial phenotypes in newborn (P0) mice. Results show that the facial skeleton is the most affected region of the cranium. Coronal suture patency shows marked variation that is not strongly correlated with skull dysmorphology. The craniofacial effects of the FGFR2 mutations are similar, but Fgfr2+/S252W mutant mice display significantly more severe dysmorphology localized to the posterior palate. Our results demonstrate that coronal suture closure is neither the primary nor the sole locus of skull dysmorphology in these mouse models for Apert syndrome, but that the face is also primarily affected.

Principles of head and neck reconstruction: an algorithm to guide flap selection.

Abstract: Advances in head and neck reconstruction have resulted in improved outcomes with single-stage repair of defects ranging from intraoral to pharyngoesophageal to skull base defects. Key to success of surgery is choosing an appropriate reconstructive option based on the patient's wishes and fitness for major surgery. Where possible, free tissue transfer provides the best functional and aesthetic outcomes for the vast majority of defects. In this article, we present an algorithm to guide choice of flap selection and review principles of reconstruction and secondary surgery for head and neck defects.

Controversies in skull reconstruction.

Abstract: In the early 1980s, it was shown that bone from the skull (membranous bone) maintained its volume to a significantly greater extent than bone from the rib and iliac crest regions (endochondral bone). However, the reason for this enhanced volume maintenance was not clarified for many years. On the basis of this enhanced volume maintenance, cranial bone became the ideal autogenous graft of choice for hard tissue repair. In the ensuing years, the current authors performed a large number of autogenous split skull cranial bone cranioplasties with significant success. However, the lure of an off-the-shelf material that obviates bone harvest remained. From 1995 to 2005, the senior author performed 20 full-thickness skull defect cranioplasty corrections using calcium phosphate cement (Norian Craniofacial Repair System; Synthes, Inc, West Chester, PA; Stryker-Leibinger, Kalamazoo, MI). Of these full-thickness defects, 16 were large (arbitrarily defined as greater than 25 cm2). In this paper, we report our long-term major and minor complication rates using this material. Because of our high, long-term complication rate (38%), we believe this material is contraindicated for large, full-thickness, skull defects (>25 cm2) and we have returned to autogenous cranial bone as the criterion standard for reconstruction in such patients.

Endoscopic endonasal skull base reconstruction using a nasal septal flap: surgical results and comparison with previous reconstructions

Abstract: The objective of this study is to evaluate the usefulness and reliability of endoscopic endonasal skull base reconstructions using a nasal septal flap. This study is designed as a retrospective review. Between April 2005 and November 2009, we performed 32 endoscopic endonasal skull base reconstructions for closure of large dural defects. Eleven patients underwent reconstructions using fat grafts or the fascia lata (non-flap group). Twenty one patients underwent reconstructions using a nasal septal flap with a balloon catheter (flap group). Incidence of postoperative cerebrospinal fluid (CSF) leaks and perioperative insertion rate of external lumbar drain (ELD) were compared between the two groups. Postoperative CSF leaks occurred in two patients (9.5%) in the flap group. Three patients (27.3%) presented CSF leaks in the non-flap group. The rate of insertion of ELD was 81.8% in the non-flap group. In the flap group, one patient (4.8%) should be placed with ELD postoperatively. The incidence of postoperative CSF leaks in the flap group was lower than in the non-flap group, whereas the rate of insertion of ELD in the non-flap group was higher than in the flap group. Endoscopic endonasal skull base reconstruction using a nasal septal flap without ELD seems to be useful and reliable for ventral skull base defects after endoscopic endonasal approaches as compared with our previous single-layer reconstructions using free fat grafts or fascia lata. The long-term effectiveness of nasal septal flaps to prevent intracranial complications should be confirmed.

Osteoderms of Simosuchus clarki (Crocodyliformes: Notosuchia) from the Late Cretaceous of Madagascar

Abstract: The pug-nosed crocodyliform Simosuchus clarki is known from several specimens that collectively preserve, in addition to the skull and postcranial endoskeletal elements, a complete complement of osteoderms covering every major body region. This comprehensive sample of osteoderms facilitates the reconstruction, from multiple sources, of the entire postcranial dermal skeleton of this crocodyliform. In this contribution, I describe the anatomy, arrangement, and histology of the osteoderms of S. clarki, and provide comments on the phylogenetic and functional importance of these structures. As in other crocodyliforms, the osteoderms of Simosuchus were organized into discrete ‘shields’ covering the dorsal and ventral regions of the trunk and tail. Simosuchus also exhibited extensive osteodermal coverage of the limbs, a feature that characterizes very few crocodyliforms. The osteoderms from different shields possess distinctive morphological features, allowing isolated osteoderms to be assigned accurate...

Description of a Nearly Complete Juvenile Skull of Diplodocus (Sauropoda: Diplodocoidea) from the Late Jurassic of North America

Abstract: More than any other sauropod dinosaur group, the long-necked herbivores belonging to Diplodocoidea have been defined by their skulls. Their unique skull shape, which is extremely elongate antorbitally, with a transversely broad, square snout packed at its anterior extreme with narrow-crowned, pencil-like teeth, has served as a touchstone for describing the biology of these animals ever since the discovery of the first skull in the late 19th century. In particular, the unusual diplodocoid skull has been discussed frequently in the context of examining feeding behavior, spawning hypotheses ranging from branch stripping, propalinal shearing, and aquatic plant ‘grazing.’ Here, we describe a juvenile skull of Diplodocus (Carnegie Museum 11255) that does not share the unusually blunted snout and anteriorly sequestered teeth seen in adult specimens, suggesting that adults and juveniles may have differed greatly in their feeding behavior, an ontogenetic distinction that may be unique among sauropodomorphs.

Skull Base Manifestations of Camurati-Engelmann Disease

Abstract: Objective To describe presenting symptoms, evaluation findings, and surgical management of cranial base hyperostosis in patients with Camurati-Engelmann disease (CED). Design Retrospective study and literature review. Setting The Mayo Clinic, Rochester, Minnesota. Patients A total of 306 patients diagnosed as having CED, including 12 primarily evaluated at our institution between 1968 and 2008, and 294 identified in the international literature. Main Outcome Measures Presenting symptoms, methods of diagnosis, treatment strategies, and patient outcomes. Results One hundred seventy-three of 306 patients (56.5%) had radiographically proven skull base hyperostosis, whereas less than one-fourth were symptomatic. The most common manifestations of cranial base involvement were hearing loss (19.0%), headache (10.4%), exophthalmos (8.2%), and frontal bossing (7.2%); less common were vision changes, vertigo, facial weakness, symptomatic brainstem compression, facial numbness, and hyposmia. Although corticosteroids and bisphosphates may treat torso and extremity involvement, they demonstrate no benefit for symptomatic skull base disease. In select symptomatic patients, aggressive decompression surgery may provide the only means of treatment. Decompression surgery is more challenging with thick sclerotic bone, loss or obscuration of bony landmarks, and decreased supratentorial space. Patients must be counseled on the increased risks associated with surgery and the potential for redeposition of bone and recurrence of symptoms. Conclusions Physicians should include CED in the differential diagnosis for patients with radiographic evidence of skull base thickening and synchronous cranial neuropathies or symptoms of elevated intracranial pressure. In mild forms of the disease, the clinical course of patients should be followed with serial examination, audiometric testing, and radiography. In select patients with progressive cranial base symptoms, aggressive wide decompression of involved neurovascular structures may provide benefit.

Treatment of anterior skull base defects by a transnasal endoscopic approach in children

Abstract: Object The object of this study was to assess the efficacy and complications of endoscopic management of anterior skull base defects. Method The authors reviewed the medical records of 28 children (20 boys and 8 girls) undergoing endoscopic repair of anterior skull base defects in their tertiary referral center between 2001 and 2008; 18 cases were congenital and 10 cases posttraumatic. During the endoscopic procedure, rigid telescopes—2.7 or 4 mm in diameter, with 0° or 30° lenses—were used. In 23 patients the anterior skull base defect was sealed with fragments of middle turbinate (bone and mucosa). In the remaining 5 patients it was sealed with cartilage harvested from the nasal septum (3 cases) or from the auricle (2 cases), fibrin glue, and oxidized cellulose. A combined external and endoscopic approach was required in 3 cases because of the size and extensions of the encephalocele. Outcome was primarily assessed by means of clinical examination, nasal fibroscopy, and imaging. Results The mean duratio...

Use of Distraction Osteogenesis to Change Endocranial Morphology in Unilateral Coronal Craniosynostosis Patients

Abstract: Background: The endocranial morphology of the skull base is an important factor in determining craniofacial asymmetry. Moreover, although the patency of cranial suture would be the first determining factor, unicoronal, unilambdoid synostosis and deformational plagiocephaly can also be differentiated by means of axis angulation of anterior and posterior cranial fossa. These findings indicate the importance of endocranial morphology in craniofacial asymmetry. The authors hypothesized that distraction of the skull base might cause stress on the skull base that could modify skull base angulation deformities. Methods: This study compared the distraction technique with traditional bone repositioning techniques for remodeling skull base axis deformities in synostotic plagiocephaly patients. The study recruited 19 unicoronal craniosynostotic patients, of whom seven underwent distraction treatment and 12 underwent traditional bone graft treatment. Results: The authors found that both approaches resulted in successful outcomes in terms of exocranial morphology correction, but that the distraction technique may offer advantages over traditional methods. Moreover, the authors found that distraction did modify the skull base angulation. Distraction created more changes in the endocranial morphology. The average correction of skull base angulation with distraction was from 164.6 to 174.3 degrees, whereas the correction for the traditional technique was from 165.2 to 166.2 degrees. The amount of change in skull base axis was statistically significant according to the Mann-Whitney test (p < 0.001), but the change in cranial index of asymmetry was not (p = 0.363). Conclusion: The skull base axis in synostotic plagiocephaly, which is composed of the anterior and posterior cranial fossa, underwent greater correction using the distraction method.

Cranial anatomy of a new genus of hyperodapedontine rhynchosaur (Diapsida, Archosauromorpha) from the Upper Triassic of southern Brazil

Abstract: Detailed description of the cranial anatomy of the rhynchosaur previously known as Scaphonyx sulcognathus allows its assignment to a new genus Teyumbaita. Two nearly complete skulls and a partial skull have been referred to the taxon, all of which come from the lower part of the Caturrita Formation, Upper Triassic of Rio Grande do Sul, southern Brazil. Cranial autapomorphies of Teyumbaita sulcognathus include anterior margin of nasal concave at midline, prefrontal separated from the ascending process of the maxilla, palatal ramus of pterygoid expanded laterally within palatines, dorsal surface of exoccipital markedly depressed, a single tooth lingually displaced from the main medial tooth-bearing area of the maxilla, and a number of other characters (such as skull broader than long; a protruding orbital anterior margin; anguli oris extending to anterior ramus of the jugal; bar between the orbit and the lower temporal fenestra wider than 0·4 of the total orbital opening; mandibular depth reaching more than 25 of the total length) support its inclusion in Hyperodapedontinae. T. sulcognathus is the only potential Norian rhynchosaur, suggesting that the group survived the end-Carnian extinction event.

The cranial base of Australopithecus afarensis: new insights from the female skull

Abstract: Cranial base morphology differs among hominoids in ways that are usually attributed to some combination of an enlarged brain, retracted face and upright locomotion in humans. The human foramen magnum is anteriorly inclined and, with the occipital condyles, is forwardly located on a broad, short and flexed basicranium; the petrous elements are coronally rotated; the glenoid region is topographically complex; the nuchal lines are low; and the nuchal plane is horizontal. Australopithecus afarensis (3.7–3.0 Ma) is the earliest known species of the australopith grade in which the adult cranial base can be assessed comprehensively. This region of the adult skull was known from fragments in the 1970s, but renewed fieldwork beginning in the 1990s at the Hadar site, Ethiopia (3.4–3.0 Ma), recovered two nearly complete crania and major portions of a third, each associated with a mandible. These new specimens confirm that in small-brained, bipedal Australopithecus the foramen magnum and occipital condyles were anteriorly sited, as in humans, but without the foramen's forward inclination. In the large male A.L. 444-2 this is associated with a short basal axis, a bilateral expansion of the base, and an inferiorly rotated, flexed occipital squama—all derived characters shared by later australopiths and humans. However, in A.L. 822-1 (a female) a more primitive morphology is present: although the foramen and condyles reside anteriorly on a short base, the nuchal lines are very high, the nuchal plane is very steep, and the base is as relatively narrow centrally. A.L. 822-1 illuminates fragmentary specimens in the 1970s Hadar collection that hint at aspects of this primitive suite, suggesting that it is a common pattern in the A. afarensis hypodigm. We explore the implications of these specimens for sexual dimorphism and evolutionary scenarios of functional integration in the hominin cranial base.

Wormian Bones in Osteogenesis Imperfecta: Correlation to Clinical Findings and Genotype

Abstract: The presence of a larger than usual number of Wormian bones (accessory skull bones completely surrounded by a suture line) is a well-known radiographic sign of osteogenesis imperfecta (OI), but the phenotypic and genotypic correlates are not well characterized. In the present study we retrospectively analyzed skull radiographs of 195 OI patients (median age 11.8 years, range 0.4-48 years; 100 female). A significant number of Wormian bones (SNWB, defined as the presence of 10 or more Wormian bones) were found in at least one patient in all of the OI types studied (I, III to VII). SNWB were observed in 35% of patients with OI type I, in 96% of patients with OI type III and 78% of patients with OI type IV. SNWB were present in 28% of patients with haploinsufficiency (nonsense and frameshift) mutations in COL1A1, in 96% of patients with helical glycine substitutions in the alpha 1 chain of collagen type I and in 72% of patients with helical glycine substitutions in the alpha 2 chain of collagen type I. Stepwise multivariate logistic regression analysis showed that height z-score, an indicator of disease severity, was inversely related with the prevalence of SNWB. SNWB were visible in 19 of the 26 patients who had skull radiographs in the first year of life, including a 2-week-old newborn. Thus, it appears that SNWB occur more frequently in more severely affected OI patients and seem to develop mostly in utero.

Pedicled Facial Buccinator (FAB) Flap: A New Flap for Reconstruction of Skull Base Defects

Abstract: Background: The expansion of endoscopic endonasal skull base surgery has resulted in an increased demand for reconstructive options. Reconstruction with vascularized tissue has proven indispensable for reliably separating the cranial contents from the paranasal sinuses following extended endoscopic endonasal approaches (EEA). The introduction of the Hadad-Bassagasteguy flap (vascular pedicle nasoseptal flap, HBF) at our institution decreased our postoperative cerebral spinal fluid (CSF) leak rates from more than 20% to less than 5%. The HBF is not always available, as the nasoseptal area or its vascular supply can be compromised by tumor or prior surgery. In an attempt to keep pace with rapidly expanding reconstructive requirements, we present the anatomic and cadaveric foundations for novel modifications of the facial artery musculo (-mucosal) (FAM[M]) and buccinator flaps to allow vascularized reconstruction of the skull base. Study Design: Feasibility. Cadaveric study. Methods: Using cadaver dissections and measurements, we investigated the feasibility of transposing pedicled buccinator myo/myomucosal flaps into the nasal cavity and skull base. Both muscular and myomuscular flaps were raised, and techniques for transposition into the nasal cavity were investigated. Three fresh and six preserved human specimens were dissected. Results: Pedicled facial buccinator flaps with and without mucosa were transposed into the nasal cavity using a variety of maxillary osteotomies. No facial incisions were required. It was demonstrated that the flaps reach the anterior skull base and planum sphenoidale. Conclusions: The transposition of pedicled buccinator muscle flaps with and without mucosa into the nasal cavity could reach the anterior skull base and planum sphenoidale, if the appropriate surgical technique is used. The pedicled Facial Buccinator Flap holds significant potential as a reconstructive alternative for a variety of skull base defects, alone or in combination with existing reconstructive options.