Inferior Sinus Research Articles

Inferior sinus venosus defect associated with incomplete cor triatriatum dexter and patent foramen ovale

Sinus venosus atrial septal defect (SVD) is a rare cardiac abnormality in adults. Particularly, the inferior type is difficult to depict by transthoracic echocardiography because of its infero-posterior location to the fossa ovalis. We describe the case of a 33-year-old woman whose chest X-ray taken during bronchopneumonia revealed a cardiomegaly. Further echocardiographic investigations showed an underlying inferior SVD, an incomplete cor triatriatum dexter and a large patent foramen ovale (PFO). The diagnosis was confirmed by cardiac magnetic resonance imaging (CMR) and during surgical repair.

Renal Anatomical Factors for the Lower Calyceal Stone Formation

The pathogenesis of urolithiasis is mainly explained with metabolic disorders. However metabolic disorders alone are not sufficient to explain this pathology. In the present study the anatomical differences in the lower calyceal stone formers were examined on both the stone forming and contralateral normal side. The objective was to assess the effect of lower pole renal anatomy on the lower calyceal stone formation. Between July 1999 and July 2004 39 patients with non-obstructed solitary lower pole stones were studied. Mean age was 47.02 years. The anatomic factors were determined on intravenous urograms (IVU). The renal length and width and the number of major and minor calices were noted. Lower pole infundibular calyceal length (ICL) and width (IW), lower infundibular length-to-width ratio were measured. The infundibulo-ureteropelvic angle (IUPA) was measured by two methods using the angle between infundibular and ureteral axes (IUPA-1), and between infundibular and ureteropelvic axes (IUPA-2). We examined a new parameter: Renal longitudinal axis-infundibulum angle (RIA) for renal stone formation. RIA was determined between two axes, including the axis connecting the central point of the pelvis opposite the margins of inferior and superior renal sinus to midpoint of renal axis and the longitudinal renal axis (Figure 2). The data of the stone forming and non-stone forming contralateral side were compared. Statistical analysis was performed by paired-t-test. The IUPA-1 of the stone forming side was more acute than the non-stone forming side, in 77% of cases. The UIPA-2 of the stone forming side was more acute than the non-stone forming side, in 72% of cases. The differences with both methods between the stone forming and contralateral normal side were statistically significant (p < 0.05). Mean ICL of stone forming side was 30.20 mm whereas it was 25.51 mm in non-stone forming contralateral side. The difference between mean ICL values was statistically significant (p < 0.05). The mean infundibular length-to-width ratio was 8.55 +/- 3.25 on the stone forming side and 7.09 +/- 2.90 on the non-stone forming contralateral side. The difference between two groups was statistically significant (p < 0.05). The differences in RIA, infundibular width (IW), renal length, renal width and the number of major and minor calyces between stone forming and non-stone forming contralateral side were not statistically significant. Anatomical disorders of lower pole collecting system may be considered as factors contributing to stone formation. IUPA (1 and 2), ICL and ICL-to-IW ratio are significantly differing factors that might predispose to lower calyceal stone formation.

Right-to-left shunting with normal pulmonary pressure complicating atrial septal defect surgery

We report on a patient in whom a right-to-left shunt with normal pulmonary arterial pressures occurred after surgery of an inferior vena caval sinus venosus-type atrial septal defect. In addition to the inferior vena cava to left atrium anatomic defect, the exceptional occurrence of a post-operative right atrial inflow stenosis contributed to the right-to-left shunting.

Spontaneous Left Atrial Dissection Presenting as Pulmonary Edema

Ahealthy 30-year-old man who had not had any prior medical or surgical history presented to the emergency department with substernal pain for 2 days that was sharp and exacerbated by inspiration and recumbency. Chest radiograph (Figure 1A) showed mild left atrial enlargement. The ECG showed normal findings. The next day, the patient complained of sudden onset of class 3 dyspnea and frothy blood-tinged sputum. Follow-up …

Microsurgical anatomy of the arterial compartment of the cavernous sinus: analysis of 24 cavernous sinus

The cavernous sinus is a complex compartment situated in both sides of the sella turcica, being its microsurgical anatomy knowledge of fundamental importance when consider to approach surgically. We studied the arterial microanatomy of 24 cavernous sinus at the microsurgical laboratory, considering that in all the internal carotid artery were filled with colored latex. The meningohypophyseal trunk was present in 18 cases (75%) with its origin in intracavernous portion of the internal carotid artery. In relation to the 18 presented cases with meningohypophyseal trunk, 14 (77.7%) had a trifurcate and 4 (23.3%) had a bifurcate pattern. The tentorial artery was present in all. Its origin was observed, arising from the meningohypophyseal trunk in 17 (70.8%) and as an isolated artery in some extension of the intracavernous portion in 7 (29.1%). An accessory tentorial artery was found in one specimen. The dorsal meningeal artery was present in 22 cases (91.6%). Its origin was in the meningohypophyseal trunk in 17 cases (77.2%), arising from internal carotid artery in 4 cases (18.1%) and from inferior hypophyseal artery in one case (4.1%).The inferior hypophyseal artery was present in all cases, having its origin at the meningohypophyseal trunk in 16 cases (66.6%). In the remaining 8 cases (33.3%) the artery was found arising alone from the intracavernous portion also. The artery of the inferior cavernous sinus or inferolateral trunk was present in all cases and had its origin from internal carotid artery in its intracavernous segment. The McConnell's artery was not found in any cavernous sinus.

Isthmus ablation with a novel microwave catheter in dogs

Typical atrial flutter is a macro-reentrant arrhythmia within the right atrium. Its zone of slow conduction is the so-called right atrial isthmus, representing the area between inferior vena cava, tricuspid annulus, and coronary sinus. Conduction block of this target area can terminate the arrhythmia and prevent reinduction. Isthmus ablation with radiofrequency (RF) energy is a well-established technique to produce conduction block. However, in most cases multiple energy applications are needed to create linear lesions. In individual cases, this results in prolonged procedure duration and, as a possible result of nontransmural lesions, recurrence of the arrhythmia. This article evaluates the feasibility and safety of a new steerable temperature-monitoring microwave ablation catheter in the production of linear lesions in the right atrial isthmus and examines both the dose-response relationship and the energy required for transmural lesions. Ablation was performed in eight open-chest mongrel dogs using a 2.450-MHz microwave generator with 35-50 W and a newly designed AFx 9-F deflectable catheter with a 25-mm antenna on the tip. The operation was performed under general anesthesia using nembutal and supported with room-air artificial respiration throughout the procedure. The study showed that the new deflectable AFx microwave catheter is a feasible and safe tool for creating long transmural linear lesions in the right isthmus. Based on this data, an appropriate catheter position, energy settings between 40 and 50 W, and application duration of approximately 90 s are needed. Also, the development of different antennas and curve shapes is recommended to simplify the ablation procedure and to target more complex arrhythmia substrates with microwave energy. Further studies are needed to determine the optimal anticoagulation procedure after microwave ablation.

How does nose blowing effect the computed tomography of paranasal sinuses in chronic sinusitis?

Objective: Our aim was to determine whether inward or outward movement of the secretions in the paranasal sinuses due to nose blowing after nasal decongestion has any effect on the paranasal sinus computed tomography (CT) images in patients with sinusitis and to asses whether nose blowing may result in misdiagnosis or overdiagnosis in radiological evaluation of sinusitis. Materials and methods: Twenty-four patients with chronic sinusitis were evaluated in an academic tertiary care hospital and data were collected prospectively. After coronal sinus computed tomography scans were performed at 100 mA setting which was half the value of the standard radiation dose suggested by the manufacturer, topical decongestion was applied to each nostril followed by nose blowing 10 min later. Sinus CT scans were then repeated at the same setting. We evaluated the mucosal thickness of medial, lateral, superior and inferior maxillary and frontal sinus walls and the maximal thickness in anterior ethmoidal cells. The measurements prior to and following nose blowing were compared with Wilcoxon signed ranks test. The obtained images were also staged using Lund–McKay staging system separately and the scores were compared with Student’s t-test. Results: We observed a tendency towards reduction in mucosal thickness after nose blowing. There were statistically significant differences between maxillary sinus inferior wall and frontal sinus inferior wall mucosal thickness values prior to and after nose blowing. The difference however was very small, about 0.5 mm in magnitude and Lund–McKay score did not change in any of the patients after nose blowing. Conclusion: Nose blowing and topical nasal decongestion does not have any effect on the diagnostic accuracy of sinus CT in chronic sinusitis patients.

Absent posteroinferior and anterosuperior atrial septal defect rims: factors affecting nonsurgical closure of large secundum defects using the amplatzer occluder

Using transesophageal echocardiography, we sought to determine the anatomic characteristics of the secundum atrial septal defects (ASDs) that extend into the inferior sinus venosus and have no posteroinferior (PI) rim, to determine the factors related to potential closure with an Amplatzer occluder. We also sought to understand why large secundum ASDs with a PI but without an anterosuperior (AS) rim may require special techniques to reorient the left atrial disk before deployment of the waist and right atrial disk. We measured the lengths of 5 separate rims of the circumferences of 76 secundum ASDs, including anteroinferior, AS, superior, posterosuperior, and PI rims. We also measured anteroposterior and superoinferior defect diameters, total septal lengths, and the ratios of defect diameter to total septal length. The atrial depth was measured at the axial angle of the delivery sheath in 5 defects with no AS rim for which special techniques were required to achieve successful closure. Of 76 secundum ASDs, 13 (17%) had no PI rim. Each defect extended from the fossa ovalis into the inferior sinus venosus. Compared with defects with a PI rim, the factors related to potential closure included 100% larger defect diameters, shorter posterosuperior rim lengths, larger defect to total septal length ratios, and completely flat posterior atrial walls. When the AS rim was absent the factors related to the need for special techniques included diameters ≥ 22 mm, atrial depth < the calculated Amplatzer occluder left atrial disk diameter, rigid wire/disk interface, and obligatory left atrial disk orientation more or less perpendicular to the atrial septal plane.

Extracellular Matrix Components in Nasal Polyposis

Objective --Macroscopically, tissue hydration in nasal polyps seems to be a phenomenon of unknown etiology. As the macromolecular composition of extracellular matrix (ECM) determines to a large extent tissue hydration, which in turn determines tissue volume, we investigated ECM components in nasal polyps (NP) in comparison to nasal mucosa of the inferior turbinate (TM) and sinus mucosa from patients with chronic sinusitis without polyps (CS). Material and Methods --The following parameters were determined: (i) the dry weight of freeze-dried NP, TM and CS; (ii) the total protein content (Bio-Rad Protein Assay) of the tissue; (iii) the quality of proteins, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE); (iv) the amount of albumin, using nephelometry; and (v) the amount of hyaluronic acid, using a chemical method: deaminative hydrolysis with carbazole. Results --In 20 NP we found a significantly elevated total protein content compared to TM (n = 20) and CS (n = 15), referred to 0.1 g dry of tissue. In SDS-PAGE of NP (n = 20) a protein band at ≈ 70 kDa, representing albumin, dominated, in comparison to TM. The amount of albumin was significantly increased in NP compared to CS and TM. In contrast, the amount of the glycosaminoglycan, hyaluronic acid, was not elevated in NP or CS. Conclusion --Albumin was significantly increased in NP and CS, possibly as a result of inflammatory plasma exudation mechanisms. Hyaluronic acid seems to play no role in the tissue hydration of NP.

Primary Intraosseous Skull Base Cavernous Hemangioma: Case Report

Primary intraosseous cavernous hemangiomas (PICHs) of the skull base are extremely rare tumors. These lesions are most common in the frontal and parietal bones of the calvarium. The authors describe a 40-year-old female who presented with progressive headaches. Serial imaging revealed a contrast-enhancing intraosseous lesion of the lateral body of the sphenoid bone and the greater wing associated with encroachment of the inferior cavernous sinus and mild posterior displacement of the cavernous carotid artery. Follow-up imaging 9 years later revealed slow growth of the lesion. The patient underwent complete excision of the PICH through an extradural frontopolar approach. Pathological examination revealed an intraosseous cavernous hemangioma. PICHs of the skull base can mimic other more common skull base lesions and thus can be difficult to diagnose preoperatively. Diagnosis is usually made at surgery. The authors review the literature regarding the clinical presentation, radiological characteristics, pathological features, and surgical management of PICHs.

Congenital arteriovenous fistula of the brain with an atrial septal defect: case report

Introduction: Aneurysmal malformation of the vein of Galen (AVG) is caused by an arteriovenous fistula (AVF) between the basal arteries and deep venous sinuses of the brain. Congenital forms of AVG are potentially fatal, leading to a left-to-right shunt and cardiomegaly, and the death is most commonly as a result of cardiac failure. We present a case with an AVF of brain with an ASD. Material and methods: A mature male baby born at gestational week 38 was admitted to PICU with tachydyspnoe 4 h after birth. Ultrasound (US) and computed tomography scans of the brain detected a large bilateral AVF with dilated basal arteries and venous sinuses (sinus petrosus, sinus confluens, sinus transvs. and sagittal inferior sinus), hydrocephalus and brain atrophy. Cardiac US showed right ventricular hypertrophy, persistent ductus Botall and ASD. The patient died of cardiac failure 6 days after birth. Results: Autopsy examination of the brain showed dilatation of the vein of Galen and venous sinuses, a large conglomerate of dilated blood vessels in the midline and left occipital lobe, oedema and hydrocephalus. Examination of the heart confirmed Us findings and showed an ostium secundum ASD. Histologically, the occipital mass revealed features of an AVF, consistent with AVG. Chronic ischaemic lesions with ferruginated neurons were also present. Conclusions: The presence of chronic hypoxic changes in the brain suggests intrauterine damage as a result of a congenital AVF. The left-to-right shunt, in addition to causing cardiomegaly, may also have interfered with the development of the atrial septum, leading to an ostium secundum ASD, aggravating the clinical course.

Diagnóstico Laboratorial da Síndrome de Cushing

A suspeita clínica de síndrome de Cushing leva obrigatoriamente a uma avaliação laboratorial, baseada nas dosagens de cortisol e de ACTH. Entretanto as dosagens basais destes hormônios não são suficientes para confirmar o diagnóstico, sendo necessários testes dinâmicos que estimulem ou inibam o eixo hipotálamo-hipófise-adrenal (HHA). A adequada interpretação das dosagens requer o conhecimento dos princípios básicos da regulação do eixo HHA, o meio e a forma (ligada ou livre) onde o hormônio será quantificado, além das características dos ensaios empregados. Numa primeira fase do diagnóstico laboratorial, é feita a documentação do hipercortisolismo endógeno, através de dosagens salivares, urinárias ou séricas de cortisol, em amostras coletadas em horários apropriados e/ou após uso de dexametasona em doses baixas (1 mg). Numa segunda fase procede-se ao diagnóstico etiológico da síndrome de Cushing empregando-se basicamente dosagens de ACTH e de cortisol após uso de doses maiores de dexametasona. Muitas vezes a complexidade da patologia exige o uso de testes funcionais mais sofisticados, como o emprego de CRH, chegando até à necessidade de cateterismo do seio petroso inferior com coleta de amostras para a dosagem de ACTH. Apresentamos também o esquema utilizado na Divisão de Endocrinologia e Metabologia da Faculdade de Medicina de Ribeirão Preto para a confirmação da existência de síndrome de Cushing e determinação de sua etiologia.

Golfo yugular prominente y su repercusión en la cirugía de los neurinomas del acústico

The jugular bulb is formed by the junction of the sigmoid sinus, inferior petrous sinus and the jugular vein. It is housed in the jugular fossa of the petrous pyramid. Variations in its size, location and relationship to the internal acoustic canal (IAC) have been reported. When the jugular bulb is located medial and less than 2 mm from the posterior wall of the internal acoustic canal, it is named as high jugular bulb. If the surgeon is not aware of this variation, damage to this structure can result in profuse haemorrhage and air embolism. This anatomical change also makes difficult the access to the intracanalicular portion of acoustic neurinomas when these tumours are excised by a retrosigmoid approach. We present the case of a patient with an acoustic schwannoma in whom a preoperative axial cranial CT revealed a high jugular bulb. To control this venous structure, we opened the IAC in a longitudinal manner achieving a total excision of the lesion preserving the function of the facial nerve. We conclude that preoperative radiological investigations in acoustic schwannomas surgery should include cranial MR and TC, to rule out the presence of a high jugular bulb. Cranial axial CT including bony windows and slices of 1.5 mm thick, should be carried out to exclude a high jugular bulb.

Clinical anatomy of the nasal process of the frontal bone (spina nasalis interna).

During endonasal frontal sinusotomy with the sharp spoon, a solid piece of bone is frequently encountered anterior to the neo-ostium. This bone may be referred to as the nasal process of the frontal bone or internal nasal spine (spina nasalis interna). A prominent spina may render an extended sinusotomy difficult and may call for use of the drill. A series of anatomic measurements is presented to illustrate the 3-dimensional anatomy of the spina nasalis and the regional anatomy. A maximum endonasal frontal sinusotomy (Draf type I-II procedure, nasofrontal approach type II) was performed on 36 anatomic specimens by means of a sharp spoon. The dimensions of the remaining nasal spine were measured subsequently together with the anterior-posterior diameter of the inferior frontal sinus, the thickness of the anterior frontal sinus wall, and the distance from the neo-ostium to the anterior ethmoidal artery. The individual microanatomy of the medial floor of the frontal sinus showed a wide range of variation. The average height of the individual spine was 10 mm, the maximum depth 6 mm. A correlation was found between the nasofrontal angle of the specimen and the anterior-posterior dimension of the spine: the more acute the angle, the thicker the spine. In three quarters of the cases, the neo-ostium was separated by just one anterior ethmoidal cell from the anterior ethmoidal artery. The presented investigations provide the surgeon with quantitative data on the individual anatomy of the nasal spine and offer additional information for selecting the appropriate surgical procedure in the individual patient.

Computer-assisted assessment of lateral column movement following plantar fascial release: A cadaveric study

In patients who fail conservative treatment, releasing the plantar fascia relieves heel pain but destabilizes the lateral column of the foot. After surgery, pain can present in the area of the sinus tarsi, extensor digitorum brevis muscle, between the fourth and fifth metatarsals, and at the calcaneocuboid joint. The precise mechanism and involved structures for this painful compensation remains unclear. The authors hypothesized that the lateral plantar fascial band, bifurcate and cervical ligaments, lateral talocalcaneal ligament, and interosseous talocalcaneal ligament become excessively strained after this surgery. Using eight cadaver lower extremity limbs amputated 7 cm above the ankle joint, structural changes in the foot in response to staged release of the plantar fascia were measured. All ligament, tendon, and osseous structures were exposed along the plantar, medial, and lateral aspects of the foot and ankle. Using a servohydraulic system, compressive loads in increasing increments (50 lbs) were applied along the tibial axis. Tissue and bony structure displacement in the foot was measured using images electronically captured from two fixed cameras and a digital camera following each load change. All measurements were made in pixels and converted to millimeters in a spreadsheet program. Except for plantar fascial measurements, data were expressed as percentage of initial baseline. As expected, increasing compressive loads changed all measurements [repeated measures ANOVA, p<.04]. When releasing the plantar fascia, the inferior sinus tarsi space widened (intact, 85.4+/-10.8%; 1/4 release, 87.7+/-13.0; 1/2 release, 88.3+/-9.2; 3/4 release, 91.2+/-8.8; p<.04). Lateral length increased and medial height decreased, while medial length and lateral height were unchanged as the fascia was sequentially released. Significant movement of the inferior sinus tarsi strained the bifurcate and cervical ligaments, the lateral talocalcaneal ligament, and interosseous talocaneal ligament, which may account for pain following surgery. The initial 1/4 cut of the plantar fascia exerted the greatest mechanical alteration of the foot, suggesting that a partial release may relieve heel pain while optimizing the patient's chances of maintaining structural integrity with 75% of the plantar fascia intact.

Transvenous Detachable Coil Embolization of Direct &amp; High-Flow Carotid-Cavernous Fistula Alternative of Transarterial Detachable Balloon Embolization

We encountered 8 cases of high-flow and direct carotid cavernous fistula (CCF) since 1994. Four patients were treated with transarterial fistula occlusions using detachable balloons before 1997. Complete obliteration of CCFs with preservation of internal carotid artery (ICA) were achieved in all 4 cases using each one balloon. Three cases were approached to the fistulas via the percutaneous transfemoral approach, but one aged patient needed a direct carotid puncture because of her tortuous vessels. Meanwhile, transvenous embolizations with detachable coils (DCs); Guglielmi detachable coil (GDC), interlocking detachable coil (IDC) and fibered platinum coil were attempted in four cases after 1997; in 2 cases after failure of transarterial approach and in 2 as initial form of treatment. All 4 cases were successfully approached to the cavernous sinuses (CS) through the inferior petorosal sinus (IPS). At first we intended to block dangerous outflow points for the superior ophthalmic vein (SOV), cortical venous reflux (CVR) and contra-lateral CS. And then obliteration of the fistulas were performed with tight packing of GDCs covering the outside of the ICA. At this time, the arteriovenous shunts were disappeared abruptly, so we finished all procedure without occlusion of IPS.We compared the two methods and concluded that the transvenous embolizaton with DCs is an useful alternative of transarterial detachable balloon therapy of high flow CCF, especially when transarterial approach is difficult or proper balloons are not available.

The cavernous sinus: topographic morphometry of its contents.

The microsurgical anatomy of the cavernous sinus of 54 Turkish adult cadaveric heads (108 specimens) was examined to provide data for major topographic aspects and morphometry of the region, which is of special clinical importance for neurosurgeons. Significant findings were: 1) the abducent nerve in the cavernous sinus was observed as one rootlet in most of the specimens (78%), two rootlets in 14%, three in 5% and four in 3% of the specimens; 2) the anterior inferior venous space was dominant in 58%, the posterior superior venous space in 16%, and an intermediate type in 29% of the specimens; 3) the artery of the inferior cavernous sinus originated from the internal carotid artery (ICA) in 74% of the cases, and 4) the dorsal meningeal artery originated from the ICA in 6 (5.5%) of the specimens.

A cadaveric study of maxillary sinus size as an aid in bone grafting of the maxillary sinus floor.

This study measured maxillary sinus volume as an aid in determining graft bone volume before grafting of the maxillary sinus floor. Maxillary sinus size was measured in 32 cadavers (59 sinuses) using casts of the maxillary sinus made using dental impression material. Anteroposterior length, height, width, and volume of the maxillary sinus (mean+/-SD) were 30.1+/-5.65 mm, 34.6+/-7.71 mm, 25.4+/-5.71 mm, and 11.3+/-4.60 cm3, respectively. When the sinus-lift procedure was simulated, inferior sinus volumes (mean +/- SD) were 3.51+/-1.23 cm3 for a 15-mm lift and 5.66+/-1.71 cm3 for a 20-mm lift. In bone grafting of the maxillary sinus floor, taking into consideration individual differences in maxillary sinus volume and resorption of the grafted bone, 4.74 cm3 or more of the graft is required for a 15-mm lift, and 7.37 cm3 or more is required for a 20-mm lift.

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

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. 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. 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. 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.

Inferior sinus venosus type of atrial septal defect

The inferior sinus venosus type of atrial septal defect is rare. It is associated with caudal displacement of the right inferior pulmonary vein and its anomalous connection to the intrapericardial segment of inferior vena cava. We have operated on 3 patients in 3 decades. The operative findings and a technique to correct these anomalies without using prosthetic material are described.