Is there an identifiable intact medial wall of the cavernous sinus? Macro- and microscopic anatomical study using sheet plastination.

BACKGROUND: The medial wall of the cavernous sinus is believed to play a significant role in determining the direction of growth of pituitary adenomas and in planning pituitary surgery. However, it remains unclear whether there is a dural wall between the pituitary gland and the cavernous sinus. OBJECTIVE: To identify and trace the membranelike structures medial to the cavernous sinus and around the pituitary gland and their relationships with surrounding structures. METHODS: Sixteen cadavers (7 females and 9 males; age range, 54-89 years; mean age, 77 years) were used in this study and prepared as 16 sets of transverse (5 sets), coronal (2 sets), and sagittal (9 sets) plastinated sections that were examined at both macro- and microscopic levels. RESULTS: The pituitary gland was fully enclosed in a fibrous capsule, but the components and thickness of the capsule varied on different aspects of the gland. The meningeal dural layer was sandwiched between the anterosuperior aspect of the gland capsule and the cavernous sinus. Posteroinferiorly, however, this dural layer disappeared as it fused with the capsule. A weblike loose fibrous network connected the capsule, carotid artery, venous plexus, and the dura of the middle cranial fossa. CONCLUSION: The medial wall of the cavernous sinus consists of both the meningeal dura and weblike loose fibrous network, which are located at the anterosuperior and posteroinferior aspects, respectively.

Expression of extracellular matrix-proteins in perisellar connective tissue and dura mater.

PURPOSE: To describe the pattern of expression of extracellular matrix (ECM) proteins in perisellar connective tissue. METHODS: Dural and perisellar specimens from ten individuals were investigated immunohistochemically for collagens I to IV, tenascin, fibronectin, elastin, laminin, and vitronectin. FINDINGS: Collagen I and III and fibronectin were strongly expressed and collagen IV, tenascin, and vitronectin were moderately expressed in the boundaries of the sella and around the CS. In six of nine specimens from the anterior boundary of the sella, and in 11 of 19 samples from the lateral boundary of the sella (medial wall of CS), two different layers could be detected by the expression of different ECM proteins. None of the antigens generally allowed differentiation between two layers of the pituitary envelope. CONCLUSIONS: The pituitary boundary may consist of a single or a double layer, infrequently differentiated from each other by the expression of different ECM proteins.

Valor predictivo de la clasificación de Knosp en el grado de resección quirúrgica de los macroadenomas invasivos. Estudio prospectivo de una serie de 23 casos / Predicitve value of the Knosp classification in the staging of invasive pituitary macroadenomas. A Prospective study of 23 cases

Objetivos. Analizar y valorar el grado de resección y las complicaciones de la cirugía transesfenoidal en una serie de 23 casos de macroadenomas con invasión del seno cavernoso evaluados mediante la clasificación de Knosp. Material, métodos y resultados. Estudio prospectivo de 22 pacientes (23 operaciones) intervenidos en nuestro centro entre Mayo del 2002 y Diciembre del 2004 de macroadenomas hipofisarios con diferentes grados de invasión del seno cavernoso según la clasificación de Knosp15. Entre las variables del estudio se incluyeron los grados de invasión y de resección postoperatoria con un seguimiento radiológico medio a largo plazo de 15 meses. Nuestra serie consta de 15 varones y 7 mujeres, con una edad media de 48 años (27 - 75 años). Todos ellos presentaban macroadenomas con afectación de uno o ambos senos cavernosos. De acuerdo con la clasificación de Knosp 4 pacientes fueron grado 1, 2 grado 2, 1 grado 3 y 16 grado 4. En 20 casos se utilizó una vía transesfenoidal clásica y en tres casos se hizo un abordaje transesfenoidal endoscópico. Según la RMN postoperatoria los grados de resección fueron: completo o total en todos los pacientes con grados 1 y 2 y en sólo 2 pacientes con grado 4; subtotal (>80%) en 1 paciente con grado 3 y en 6 pacientes con grado 4 y parcial (<80%) en 7 pacientes con grado 4 de Knosp. Se compararon los grados de resección versus los grados de invasión mediante el Test exacto de Fsiher y las diferencias no fueron estadísticamente significativas (p=0,12). Discusión y conclusiones. Si bien únicamente la clasificación radiológica de Knosp por si sola no puede predecir el comportamiento biológico del tumor o si la pared medial del seno cavernoso está infiltrado o desplazada, en nuestra serie los tumores de grado 4 han sido los que han presentado un peor resultado de acuerdo al grado de resección. En los tumores que invaden el seno cavernoso, incluso en los caos donde la carótida está englobada en posible realizar resecciones completas con una morbimortalidad aceptable (AU)

Objective. To evaluate our experience regarding the treatment of pituitary macroadenomas with cavernous sinus invasion in a series of 23 cases of transphenoidal resection. Materials, methods and results. Twenty two patients, fifteen males and seven females, with ages ranging from 27 to 75 (mean of 48), were operated under protocol by a single surgeon between May of 2002 and December of 2004. Preoperatively all lesions were diagnosed by MRI and staged according to the Knosp classification. All tumors had extension to one or both cavernous sinuses. Four patients were considered to be grade 1, two grade 2, one grade 3 and sixteen grade 4. Twenty three operations were performed on twenty-two patients. Twenty cases were the standard transsphenoidal approach, and three were endoscopic. Postoperatively, the excision was classified as Complete or Total, Subtotal or Partial. Mean follow up was 15 months. The variables considered for analysis include invasion and resection grades. All six patients with graded 1 and 2 lesions and two patients with grade 4 lesions underwent a complete resection. Subtotal (greater than 80%) excision was achieved in one patient with a grade 3 tumor and six patients with grade 4 tumors. The remaining seven patients with grade 4 adenomas had a Partial (less than 80%) excision. We compare de resection grade versus invasion grade with exact Fisher test. And there is not estadistical difference (p=0.12). Conclusion. The Knosp classification alone cannot predict the behavior of these tumors. In our experience, despite tumor extension to the cavernous sinus, pituitary macroadenomas can be safely resected with low morbidity and mortality (AU)

Innervation of the maxillary vibrissae in mice as revealed by anterograde and retrograde tract tracing.

Vibrissae are a unique sensory system of mammals that is characterized by a rich and diverse innervation involved in numerous sensory tasks with the potential for species-specific differences. In the present study, indocarbocyanine dyes (DiI and PTIR271) and confocal microscopy were combined to study the innervation of the mystacial vibrissae and vibrissa-specific sensory neuron distribution in the maxillary portion of the trigeminal ganglion of the mouse. The deeper regions of the vibrissa cavernous sinus (CS) contained a dense plexus of free nerve endings, possibly of autonomic fibers. The superficial part of this sinus displayed a massive array of corpuscular endings. Innervation in the region of the ring sinus consisted of Merkel endings and different morphological variances of lanceolate endings. The region of the inner conical body had a circular plexus of free nerve endings. In addition to confirming previous observations obtained by a variety of other techniques and ultrastructural studies, our studies revealed denser terminal receptor endings in a different distribution pattern than previously demonstrated in studies using the rat. We also revealed the distribution of sensory neurons in the trigeminal ganglion using retrograde tracing with fluorescent tracers from two nearby vibrissae. We determined that the populations of sensory neurons innervating the two vibrissae were largely overlapping. This suggests that the somatotopic maps of vibrissal projections reported at the different levels in the neuraxis are not faithfully reproduced at the level of the ganglion.

Similarities and differences in the innervation of mystacial vibrissal follicle-sinus complexes in the rat and cat: a confocal microscopic study.

Our confocal three-dimensional analyses revealed substantial differences in the innervation to vibrissal follicle-sinus complexes (FSCs) in the rat and cat. This is the first study using anti-protein gene product 9.5 (PGP9.5) immunolabeling and confocal microscopy on thick sections to examine systematically the terminal arborizations of the various FSC endings and to compare them between two species, the rat and the cat, that have similar-appearing FSCs but different exploratory behaviors, such as existence or absence of whisking. At least eight distinct endings were clearly discriminated three dimensionally in this study: 1) Merkel endings at the rete ridge collar, 2) circumferentially oriented lanceolate endings, 3) Merkel endings at the level of the ring sinus, 4) longitudinally oriented lanceolate endings, 5) club-like ringwulst endings, 6) reticular endings, 7) spiny endings, and 8) encapsulated endings. Of particular contrast, each nerve fiber that innervates Merkel cells at the level of the ring sinus in the rat usually terminates as a single, relatively small cluster of endings, whereas in the cat they terminate en passant as several large clusters of endings. Also, individual arbors of reticular endings in the rat ramify parallel to the vibrissae and distribute over wide, overlapping territories, whereas those in the cat ramify perpendicular and terminate in tightly circumscribed territories. Otherwise, the inner conical body of rat FSCs contains en passant, circumferentially oriented lanceolate endings that are lacking in the cat, whereas the cavernous sinus of the cat has en passant corpuscular endings that are lacking in the rat. Surprisingly, the one type of innervation that is the most similar in both species is a major set of simple, club-like endings, located at the attachment of the ringwulst, that had not previously been recognized as a morphologically unique type of innervation. Although the basic structure of the FSCs is similar in the rat and cat, the numerous differences in innervation suggest that these species would have different tactile capabilities and perceptions possibly related to their different vibrissa-related exploratory behaviors.

Comparative microanatomy of the lateral wall of the 'cavernous sinus' in humans and the olive baboon.

Despite many studies of the 'cavernous sinus' lateral wall, the anatomy of this area remains controversial. We performed a comparative microanatomical and histoarchitectural study in 14 humans and in 10 nonhuman primates (Papio cynocephalus anubis). Venous channels and cranial nerves were embedded in the 'interperiosteodural space'. The dura propria of the lateral wall could be removed without entering the venous compartment. The oculomotor and trochlear nerves were accompanied by an arachnoidal and dural sheath. The oculomotor nerve sheath stopped under the anterior clinoid process in baboons. The trigeminal ganglion was covered posteriorly with an arachnoid membrane and adhered firmly to the dura propria on lateral and anterior sections. The three branches of the trigeminal nerve had no arachnoid covering, except for arachnoid granulations in humans. In baboons, the oculomotor and trochlear nerves were thicker than in humans, while the ophthalmic nerve was thinner. The abducens nerve belonged to the lateral wall of the sinus in baboons and had no arachnoidal sheath except in the first millimeters of Dorello's canal. After leaving their arachnoidal and dural sheath, the intracavernous cranial nerves acquired a typical peripheral sheath. The venous channels in both species were true dural sinuses. Willis cords and adipose tissue were identified.

Histomorphologic structure of the carotid rete-cavernous sinus complex and its functional importance in sheep (Ovis aries).

Paraffin sections of the carotid rete-cavernous sinus complex of sheep were studied, using different stains. The carotid rete of sheep was composed of medium-sized arteries with smooth muscle layers that were oriented in different directions. The carotid body cells may have migrated proximally in the adventitia of the intracranial portion of the internal carotid artery as its extracranial portion degenerates early in life. The cavernous sinus shared a common tunica adventitia with surrounding rete branches. At places, the wall of the cavernous sinus had a distinct tunica media interposed between the endothelial cells and the tunica adventitia. Therefore, the name cavernous venous plexus has been proposed for the cavernous sinus in sheep.