Sinus Compartments Research Articles

Circumferential exposure of the cavernous sinus and parasellar region through a combined open and endoscopic endonasal transcavernous approach, a morphometric study.

Although recent trends currently favor the endoscopic endonasal transcavernous approach (EETA) over the pretemporal transcavernous approach (PTA) for certain cavernous sinus pathologies, dedicated assessment of the surgical exposure and maneuverability is wanting. Toward this aim, this morphometric study quantifies these variables within four cavernous sinus compartments by comparing the PTA, EETA, and a combined approach to achieve a circumferential dissection (EETA-PTA). In five latex-injected specimens, exposure volumes of the EETA, PTA, and circumferential EETA-PTA approaches were quantified; the latter combined the most conservative options of both the endoscopic and open approaches. Two clinical cases illustrate the combined approach. EETA-PTA provided the largest volume of exposure (65.6% vs 35% PTA vs 44.6% EETA, P = 0.01) and eliminated the need to mobilize the ICA or cross cranial nerves. Although EETA and PTA approaches afforded comparable exposure volumes along the entire cavernous sinus (34.9 vs 44.6%), the EETA better exposed medial and inferior compartments (whereas the PTA exposed larger volumes in the lateral and superior compartments. The combined EETA-PTA yielded 66% of total cavernous sinus exposure volumes and eliminated the need to mobilize the ICA or cross cranial nerves. Our methodology aligns with strategies that use a modular concept to divide the skull base into compartments for maximal safe resection. Excluding soft tumors, the EETA is preferred for medial and inferior lesions and the PTA for superior and lateral lesions. A staged combined EETA-PTA may safely yield a 360-degree access for extensive multi-compartment lesions that span neurovascular structures within the cavernous sinus.

Septic suturitis: A suspected cause of periapical infection in a young horse

SummaryThis case report describes septic suturitis as a likely cause of periapical dental disease in a 3‐year‐old Thoroughbred colt. The horse was presented for a unilateral sinusitis initially managed by a frontal osteotomy and sinus lavage and subsequently developed a septic suturitis. Subsequently, a computed tomography (CT) examination identified a periapical infection of cheek tooth 109 with associated sinusitis of the rostral sinus compartments and an extensive suturitis, with the most severe changes located at the right nasomaxillary suture line. There was an associated local fistulous tract rostral to the mesial periapical region of cheek tooth 107 but unassociated with typical periapical or endodontic dental disease changes on CT. The sinusitis did not respond to oral extraction of cheek tooth 109 and sinus lavage. A repeat head CT 2 weeks later, now revealed buccal alveolar bone loss surrounding cheek tooth 107 with obvious periodontal and endodontic dental disease changes. Oral extraction of cheek tooth 107 was performed and local curettage of the fistulous tract was conducted. We conclude that septic suturitis can become extensive and slow to resolve and its rostral extension can cause periapical infection of the closely associated rostral cheek teeth in young horses.

Pituitary adenoma with cavernous sinus compartment penetration and intracranial extension: surgical anatomy, approach, and outcomes.

To understand the different characteristics and growth corridors of knosp grade 4 pituitary adenomas (Knosp4PA) with cavernous sinus (CS) compartments penetration and intracranial extension, aiming to improve the safety, effectiveness, and total resection rate of surgery. A case series of 120 Knosp4PA patients with 187 invaded compartments were retrospectively reviewed. A novel surgery-relevant grading system was proposed according to the CS penetrating features. The details of approach drafting, risk prediction, and complication avoidance were analyzed and integrated through illustrated cases. All enrolled tumor was Knosp4PA which was derived from Knosp subgrades 3A(62.5%) and 3B(37.5%). Based on the tumor growth pathway and its relevant features, five subclassifications of intracranial extension(n=98,81.7%) were classified, which derived from the superior (Dolenc's and Oculomotor subtype, 5% and 24.2%), lateral (Parkinson's subtype,18.3%), and posterior (cerebral peduncle and Dorello's subtype, 5.8% and 1.7%) CS compartment penetration. The size of intracranial extension is assessed by Lou's scale proposed here based on preoperative MRI characteristics. Under Lou's scale, the gross total rate (GTR) decreased (82%, 53%, 22%, and 19%) with grades increased (grade 0,1,2,3, respectively), and presents significant difference between the four groups (p=0.000), as well as between single and multiple compartments involved (p=0.001). Preoperative cranial nerve deficits included the optic nerve (53%), oculomotor nerve (24.2%), and abducent nerve (4.2%), with an overall rate of visual function improvement in 68.1%. Postoperative complications of transient diabetes insipidus, cerebrospinal fluid (CSF) leakage, and cranial nerve deficits were 6.7%, 0.8%, and 0%. No new cranial nerve deficits occurred. The mortality rate was 0.8%. The concept of "penetration" refines the extracavernous growth pattern, and the five intracranial subclassifications help to understand the potential extension corridors, enhancing adequate exposure and targeted resection of Knosp4PA. This grading system may benefit from its predictive and prognostic value, from which a higher GTR rate can be achieved.

Anatomy and computed tomography of the nasal cavity, nasal conchae, and paranasal sinuses of the endangered Patagonian huemul deer (Hippocamelus bisulcus).

This study explores for the first time the shape, volume, and configuration of nasal cavity structures of the endangered Patagonian huemul deer via computed tomography (CT). Three-dimensional (3D) reconstructions derived from data sets obtained from five Patagonian huemul deer skulls were analyzed. Using semiautomatic segmentation, 3D models were created of all the sinus compartments and nasal conchae. Volumetric measurements were taken of seven sinus compartments. The Patagonian huemul deer has a wide, large nasal cavity, with an osseous nasal aperture typical of cervids and a choana with characteristics that differentiate it from the pudu and roe deer. It also has six nasal meatuses and three nasal conchae, with the ventral nasal concha having the greatest volume and surface, which given its extension ensures a greater ability to humidify and heat the air. Further analysis showed the complex system of paranasal sinuses to be characterized by a rostroventral and interconnected group, where communication with the nasal cavity is common through the nasomaxillary opening, and a caudodorsal group that communicates with the nasal cavity through openings in the nasal meatuses. Our study of the endangered Patagonian huemul deer documents an intricate, and in some nasal cavity structures, unique morphological construction which may predispose it to higher rates of sinonasal afflictions due largely to its nasal complex anatomy, thus affecting its high cultural value.

524 Cytodifferentiation of Pituitary Tumors Influences Pathogenesis and Cavernous Sinus Invasion

INTRODUCTION: Pituitary neuroendocrine tumors (PitNET) continue to offer unique challenges given their proximity to the cavernous sinus, whereby invasive behavior can dictate extent of resection and surgical outcome, especially in neuroendocrine-active tumors. Recent advances in surgical techniques have resulted in the development of transcavernous endonasal surgery for invasive tumors. METHODS: 169 consecutive primary PitNET were analyzed, of which 45% were neuroendocrine-active. There were 64 PIT-1, 62 SF-1, 38 TPIT, and 5 none-staining PitNets. The gold standard for cavernous sinus invasion was based on histopathological examination of the cavernous sinus medial wall and intraoperative exploration of cavernous sinus compartments. RESULTS: Cavernous sinus disease was present in 33% of patients. PIT-1 tumors had a significantly higher predilection for cavernous sinus invasion, 53% versus 24% and 18% for TPIT and SF-1 tumors, respectively (OR 6.13, 95% CI 1.08-2.58; p<0.001). For Knosp 0-2 tumors, 44% of PIT-1 tumors had cavernous sinus invasion compared to 7% and 13% for TPIT and SF-1 tumors, respectively (p < 0.01). Utilizing the transcavernous approach, surgical biochemical remission rates for patients with acromegaly, hyperprolactinemia, and Cushing’s disease were 88%, 87%, and 94%, respectively. Granulation pattern of PIT-1 tumors, corticotroph functional status, and Crooke’s cell corticotroph morphology did not influence cavernous sinus invasion. CONCLUSIONS: Likelihood of cavernous sinus invasion differed by transcription factor expression; PIT-1 expressing somatotroph and lactotroph tumors had a higher predilection for invading the cavernous sinus compared to other tumor subtypes. This elucidates a unique cavernoinvasive behavior absent in cells from other lineages. Innovative surgical techniques, however, can mitigate tumor behavior and achieve robust, reproducible biochemical remission and gross total resection rates. These findings can have considerable implications on the surgical management and study of PitNET biology and behavior.

Intracranial Breakthrough Through Cavernous Sinus Compartments: Anatomic Study and Implications for Pituitary Adenoma Surgery.

Pituitary adenomas (PAs) with cavernous sinus (CS) invasion can extend into the intradural space by breaking through the CS walls. To elaborate on the potential breakthrough route through CS compartments for invasive PAs and describe relevant surgical anatomy and technical nuances, with an aim to improve resection rates. Twelve colored silicon-injected human head specimens were used for endonasal and transcranial dissection of the CS walls; ligaments, dural folds, and cranial nerves on each compartment were inspected. Two illustrative cases of invasive PA are also presented. The potential breakthrough routes through the CS compartments had unique anatomic features. The superior compartment breakthrough was delimited by the anterior petroclinoidal ligament laterally, posterior petroclinoidal ligament posteriorly, and interclinoidal ligament medially; tumor extended into the parapeduncular space with an intimate spatial relationship with the oculomotor nerve and posterior communicating artery. The lateral compartment breakthrough was limited by the anterior petroclinoidal ligament superiorly and ophthalmic nerve inferiorly; tumor extended into the middle fossa, displacing the trochlear nerve and inferolateral trunk to reach the medial temporal lobe. The posterior compartment breakthrough delineated by the Gruber ligament, petrosal process of the sphenoid bone, and petrous apex inferiorly, posterior petroclinoidal ligament superiorly, and dorsum sellae medially; tumor displaced or encased the abducens nerve and inferior hypophyseal artery and compressed the cerebral peduncle. The superior lateral and posterior components of the CS are potential routes for invasion by PAs. Better identification of CS breakthrough patterns is crucial for achieving higher gross total resection and remission rates.

Unilateral, Rostral Maxillary Sinusitis Resulting from Displacement and Retention of an Alveolar Plug in a 4-Year-Old Horse.

Sinusitis is a common occurrence in horses and often develops secondary to dental disease. Extraction of cheek teeth in horses is associated with variable degrees of complications and although postoperative displacement and retention of alveolar plugs has been identified as one such potential complication, few cases of resulting sinusitis have been reported. This manuscript describes a four-year-old Thoroughbred mare that was presented for chronic unilateral left-sided mucopurulent nasal discharge after extraction of the left maxillary second molar tooth two months earlier. Radiographic and computed tomographic (CT) examinations revealed a well circumscribed, soft tissue opacity in the left rostral sinus compartment. Intraoral examination revealed feed impacted in the alveolus of the extracted tooth and an oral sinus fistula. Upper airway endoscopy showed thick, purulent material at the nasomaxillary aperture. Sinoscopy showed unexpectedly clean frontal, dorsal conchal and caudal maxillary sinuses. The alveolar dental plug associated with previous exodontia became apparent within the sinus and was removed through the sinoscopy portal. Repeat endoscopies confirmed progressive clearance of the sinusitis during hospitalization. Unilateral nasal discharge returned three months later. An abscess within the sinus had formed. Complete resolution of the sinusitis was achieved after lancing the abscess and further sinus lavage. Sinoscopy through a frontal sinus trephination portal proved useful in diagnosis and treatment. Detailed evaluation of structures allowed for rapid establishment of adequate drainage and communication between all sinus compartments without osteoplastic surgery.

Diagnosis and Surgical Treatment of Idiopathic Primary Sino-Nasal Obstruction in Miniature Horse Breeds: Long-Term Follow-Up of Seven Cases.

Idiopathic sino-nasal obstruction resulting in retention of large amounts of liquid in the paranasal sinus compartments was diagnosed in seven young (2. 2 ± 0.7 years) miniature-breed horses based on clinical, endoscopic, radiographic, and CT scan examinations. The most prevalent clinical signs included decreased or no airflow from the nostril(s) (7/7) and nasal discharge (6/7). The problem presented bilaterally in six of seven cases. An alternative sino-nasal communication was created through bone flap osteotomy surgery and perforation of the ventromedial floor of the dorsal conchae in all cases, followed by fixation of silicone irrigation tubes/Foley catheters in six of seven cases to keep the newly created ostium patent. This resulted in long-term resolution of the problem with good cosmetic appearance in all animals following a median period of 19 months. Premature loss of fixed tubes was reported in three cases.

Extended Middle Fossa Approach for Trigeminal Schwannoma Resection.

Trigeminal schwannomas are rare benign tumors, it is second most common intracranial schwannomas after vestibular schwannomas. The management includes not limited to observation, stereotactic radiosurgery/radiotherapy, and/or surgical resection. Tumor size and patient clinical status are the most important factors in management.In this video, we describe the technical nuances of an extended middle fossa approach for large trigeminal schwannoma with cavernous sinus extension resection. A 44-year-old right-handed female with several months' history of progressive right facial paresthesia and pain in the distribution of V3 mainly. On physical examination, she had decreased sensation to light touch over the right V1 to V3 distribution with loss of cornel reflex. The brain MRI showed 3.5 cm bilobed mass extends from the pontine root entry zone to the cavernous sinus. Craniotomy was performed and followed by middle fossa dural peeling, peeling of temporal lobe dura away from the wall of the cavernous sinus, extradurally anterior clinoidectomy, drilling of the petrous apex, coagulation of superior petrosal sinus followed incision of the tentorium up to the tentorial notch with preservation the fourth cranial nerve, and tumor dissected away from V1 and then gradually removed from the superior wall of the cavernous sinus.The technique presented here allows for complete tumor resection, safe navigation through the relative cavernous sinus compartments, and minimizes the possibility of inadvertent injury to the cranial nerves.The postoperative course was uneventful except for right eye incomplete ptosis from the swelling. Her facial pain subsided after the surgery without any extra ocular movement impairment. The link to the video can be found at: https://youtu.be/zxi2XK2R9QU .

Volumetric measurements of paranasal sinuses and examination of sinonasal communication in healthy Shetland ponies: anatomical and morphometric characteristics using computed tomography

BackgroundDespite clinical importance and frequent occurrence of sinus disease, little is known about the size of paranasal sinuses and their communication in ponies and small horses. To examine the shape and volume of the paranasal sinuses and evaluate the sinonasal communication, three-dimensional (3D) reconstructions of computed tomography (CT) datasets of 12 healthy adult Shetland ponies were performed and analysed. Linear measurements of head length and width were taken. Using semi-automatic segmentation, 3D-models of all sinus compartments were created. Volumetric measurement of the seven sinus compartments were conducted and statistical analysis was performed. Sinus volumes were compared between the left and right sinuses and the relation to age and head size was evaluated.ResultsStructure and shape of the paranasal sinus system in Shetland ponies was similar to that of large horses. All seven sinus compartments on each side of the head were identified (rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, middle conchal sinus, frontal sinus, sphenopalatine sinus). The existence of a bilateral cranial and a caudal system formed by a maxillary septum was visible in all 12 individuals. The volumetric sizes of the left and right sinuses did not differ significantly (p > 0.05). A positive correlation between the size of the paranasal sinuses and the head length was shown. A relation between sinus volumes and age could not be proved in adult ponies aged > six years. Communication between single sinus compartments was identified. Furthermore, communication with the nasal cavity over the nasomaxillary aperture (Apertura nasomaxillaris) and a common sinonasal channel (Canalis sinunasalis communis) as well as its splitting up into a rostral and a caudolateral channel could be seen. Examination of the sinonasal communication was challenging and only a descriptive evaluation was possible.ConclusionsOur findings concerning the size, shape and volumetric dimensions of Shetland pony CT images could help improve CT interpretation of abnormal clinical cases as well as aiding clinicians to develop and select appropriate instruments for medical inspection and treatments.

Computed Tomographic Assessment of Individual Paranasal Sinus Compartment and Nasal Conchal Bulla Involvement in 300 Cases of Equine Sinonasal Disease.

Background: Computed tomographic (CT) imaging has allowed new anatomical studies and detailed clinical imaging of the complex, overlapping equine sinonasal structures. Despite the widespread use of CT, no study has specifically identified which compartments are most commonly affected with sinus disorders. CT has also shown the presence of intercurrent, ipsilateral nasal disorders, especially infection of the nasal conchal bullae (NCB) in many cases of sinus disease, but the frequency of intercurrent NCB infections has not been reported.Objectives: To identify which sinus compartments are most commonly affected in horses with clinical sinus disorders and to record the prevalence of NCB involvement in such cases.Study Design: Retrospective examination of CT images of horses with confirmed unilateral sinus disease.Methods: The CT images of 300 horses, from three different equine hospitals with clinically confirmed sinus disease [mainly dental (53%) and primary sinusitis (25.7%)] were retrospectively examined to determine which sinus compartments and NCBs were affected.Results: The rostral, more dependent sinus compartments were most commonly involved, i.e., the rostral maxillary sinus in 284/300 (94.7% affected) and the ventral conchal sinus (87% affected). The caudal maxillary sinus (65.3%), dorsal conchal sinus (52.7%), frontal sinus (26%), ethmoidal sinus (32%) and sphenopalatine sinus (28.7%) were less commonly affected. There was infection or destruction of the ipsilateral NCBs in 56% of horses with sinus disorders, including the ventral NCBs in 42.3%, dorsal NCBs in 29% and both NCBs in 18% of cases.Main Limitations: The horses with sinonasal disease that underwent head CT imaging include more problematic cases and horses of high value, rather than the general horse population.Conclusions: The more dependant (i.e., the RMS and VCS) sinus compartments are most commonly involved in sinus disorders, with the RMS involved in nearly every case. The more dorsally located sinuses (i.e., caudal group) are less commonly involved. Many horses with sinus disease also have disorders of their nasal conchal bullae and so the term sinonasal disease seems appropriate for these disorders.

Comparative studies on the histological characteristics of equine nasomaxillary aperture and paranasal sinus mucosa considering topographic and age-related differences

BackgroundHorses may acquire a range of paranasal sinus diseases. Clinical studies show slight differences regarding anatomical regions and age. Histopathological examination of tissue samples could play an important role in the diagnostic process. Therefore, detailed knowledge of the histological appearance of the paranasal sinus mucosa (PSM) and the nasomaxillary aperture mucosa (NAM) is essential. The objective of this study was to determine topographic and age-related differences within the healthy equine PSM. In addition, we aimed to gain detailed knowledge of the histological appearance of the NAM in comparison to the PSM.ResultsThe PSM had an average height of 75.72 ± 44.48 μm with a two-row pseudostratified columnar epithelium of 13.52 ± 4.78 μm. The parameters mucosal height, epithelial height and number of goblet cells revealed significant dependency of the sample site and age group. The maxillary and dorsal conchal sinus showed the highest values for these parameters. In terms of age, younger horses showed a significantly higher total mucosal height in contrast to a significantly lower epithelial height than older horses. Positive correlation was seen between the epithelial height and number of goblet cells. The NAM had an average height of 820.27 ± 653.21 μm. Its pseudostratified epithelium was usually arranged in three rows and had an average height of 44.9 ± 12.78 μm. The number of goblet cells in the NAM was five times higher than in the PSM. Serous glands were found in only 4% of the PSM samples and 100% of the NAM samples.ConclusionsThere are significant histological differences between different paranasal sinus sites and between different groups of age. This may be related to an altered susceptibility for certain pathologies. The striking difference in the histological appearance of the NAM compared to the PSM could be due to an enhanced role in mucociliary clearance. Further studies are necessary to improve the understanding of mucosal function in specific paranasal sinus compartments and mucosal changes generated by different diseases.

Validation of a 2‐mm videoendoscope for the evaluation of the paranasal sinuses with a minimally invasive technique

To describe the technique, experience, and limitations of using a 2-mm flexible endoscope to perform standing minimally invasive sinoscopy. In phases 1 and 2, we used cadaveric heads (ex vivo). In phase 3, we used unaffected horses (in vivo). Five cadaveric equine skulls in phase 1 and 10 cadaveric equine skulls in phase 2. Six horses older than 5 years in phase 3. In phase 1, the specimens were used to determine the suitability of the endoscope for sinoscopy and the ideal landmarks to approach the paranasal sinuses through minisinusotomies performed with a 14 gauge needle. In phase 2, a nonblinded evaluation of the visualization of the different sinus compartments was performed, and a score was attributed to each structure. Procedures were video recorded and compared with direct visualization of the sinuses after performing frontal and maxillary flaps. In phase 3, the technique was validated in healthy horses under sedation. The landmarks determined in phase 1 allowed a thorough exploration of the sinuses in phases 2 and 3. Sinoscopy findings were confirmed after direct visualization of the sinuses via frontal and maxillary bone flaps in phase 2. The procedure was well tolerated by all horses. Minimally invasive sinoscopy was readily performed without relevant complications in standing horses. A thorough evaluation of most sinus structures was obtained only using the frontal and the rostral maxillary portals. Minimally invasive sinoscopy offers an alternative diagnostic tool to veterinarians. A specialized endoscope and appropriate training are required to perform this minimally invasive procedure.

Missed paranasal sinus compartments in sinus surgery with and without image-guidance systems: a pilot feasibility study.

Image-guidance systems (IGS) have gained widespread use in endoscopic sinus surgery (ESS) and have been thoroughly analysed. In this study, we looked for a new parameter to determine if patients could directly benefit from the use of IGS during primary ESS. We questioned if IGS could improve the quality of ESS in chronic rhinosinusitis (CRS) patients via allowing a more comprehensive treatment of all involved sinus compartments. In a pilot feasibility study, we evaluated uncomplicated CRS patients following primary ESS with and without IGS between January 2011 and June 2012 using preoperative and postoperative CT scans. The preoperative CT scans identified the sinus compartments requiring surgery. The postoperative CT scans were used to evaluate the treatment effect in these compartments. From these data, we calculated a missing ratio (missed compartments/compartments requiring surgery) for each patient. Of the 169 ESS patients who were treated, ten patients were retrospectively identified as complying with the inclusion and exclusion criteria following ESS with IGS. Ten patients treated without IGS were then randomly chosen. The median missing ratio for non-IGS patients was 36%, and for IGS patients, the median missing ratio was 0% (p = 0.046). However, the missing ratio was depended on the number of compartments requiring surgery. Stratification of the number of compartments requiring surgery resulted in an exact p value of 0.13. IGS could help the surgeon to more completely address diseased sinus compartments. For better scientific merit, a comparative study of ESS with and without IGS seems feasible, using the proposed failing score missed compartments/compartments requiring surgery as the primary outcome parameter.

Computed tomographic assessment of equine maxillary cheek teeth anatomical relationships, and paranasal sinus volumes

Disorders affecting the equine maxillary cheek teeth and paranasal sinuses are relatively common, but limited objective information is available on the dimensions and relationships of these structures in horses of...

Cavernous sinus compartments from the endoscopic endonasal approach: anatomical considerations and surgical relevance to adenoma surgery.

OBJECTIVE Tumors with cavernous sinus (CS) invasion represent a neurosurgical challenge. Increasing application of the endoscopic endonasal approach (EEA) requires a thorough understanding of the CS anatomy from an endonasal perspective. In this study, the authors aimed to develop a surgical anatomy-based classification of the CS and establish its utility for preoperative surgical planning and intraoperative guidance in adenoma surgery. METHODS Twenty-five colored silicon-injected human head specimens were used for endonasal and transcranial dissections of the CS. Pre- and postoperative MRI studies of 98 patients with pituitary adenoma with intraoperatively confirmed CS invasion were analyzed. RESULTS Four CS compartments are described based on their spatial relationship with the cavernous ICA: superior, posterior, inferior, and lateral. Each compartment has distinct boundaries and dural and neurovascular relationships: the superior compartment relates to the interclinoidal ligament and oculomotor nerve, the posterior compartment bears the gulfar segment of the abducens nerve and inferior hypophyseal artery, the inferior compartment contains the sympathetic nerve and distal cavernous abducens nerve, and the lateral compartment includes all cavernous cranial nerves and the inferolateral arterial trunk. Twenty-nine patients had a single compartment invaded, and 69 had multiple compartments involved. The most commonly invaded compartment was the superior (79 patients), followed by the posterior (n = 64), inferior (n = 45), and lateral (n = 23) compartments. Residual tumor rates by compartment were 79% in lateral, 17% in posterior, 14% in superior, and 11% in inferior. CONCLUSIONS The anatomy-based classification presented here complements current imaging-based classifications and may help to identify involved compartments both preoperatively and intraoperatively.

Cavernous Sinus Compartments from an Endoscopic Endonasal Approach: Proposed Anatomical Compartments and Surgical Relevance

Introduction: Lesions involving cavernous sinus (CS) are surgically challenging because of the risk of neurovascular injury. Conventional anatomical classification is based on open approaches. We aimed to redefine this anatomy from an endonasal perspective and evaluate surgical results in relation to CS invasion by pituitary adenomas.

The sinonasal communication in the horse: examinations using computerized three-dimensional reformatted renderings of computed-tomography datasets

BackgroundSinusitis is a common disease in the horse. In human medicine it is described, that obstruction of the sinonasal communication plays a major role in the development of sinusitis. To get spatial sense of the equine specific communication ways between the nasal cavity and the paranasal sinuses, heads of 19 horses, aged 2 to 26 years, were analyzed using three-dimensional (3D) reformatted renderings of CT-datasets. Three-dimensional models were generated following manual and semi-automated segmentation. Before segmentation, the two-dimensional (2D) CT-images were verified against corresponding frozen sections of cadaveric heads.ResultsThree-dimensional analysis of the paranasal sinuses showed the bilateral existence of seven sinus compartments: rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, frontal sinus, sphenopalatine sinus and middle conchal sinus. The maxillary septum divides these seven compartments into two sinus systems: a rostral paranasal sinus system composed of the rostral maxillary sinus and the ventral conchal sinus and a caudal paranasal sinus system which comprises all other sinuses. The generated 3D models revealed a typically configuration of the sinonasal communication ways. The sinonasal communication started within the middle nasal meatus at the nasomaxillary aperture (Apertura nasomaxillaris), which opens in a common sinonasal channel (Canalis sinunasalis communis). This common sinonasal channel ramifies into a rostral sinonasal channel (Canalis sinunasalis rostralis) and a caudo-lateral sinonasal channel (Canalis sinunasalis caudalis). The rostral sinonasal channel ventilated the rostral paranasal sinus system, the caudo-lateral sinonasal channel opened into the caudal paranasal sinus system. The rostral sinonasal channel was connected to the rostral paranasal sinuses in various ways. Whereas, the caudal channel showed less anatomical variations and was in all cases connected to the caudal maxillary sinus. Volumetric measurements of the sinonasal channels showed no statistically significant differences (P <0.05) between the right and left side of the head.ConclusionsUnder physiologic conditions both paranasal sinus systems are connected to the nasal cavity by equine specific sinonasal channels. To resolve sinus disease it is aimed to maintain or even reconstruct the normal anatomy of the sinonasal communication by surgical intervention. Therefore, the presented 3D analyses may provide a useful basis.

USING SEMI‐AUTOMATED SEGMENTATION OF COMPUTED TOMOGRAPHY DATASETS FOR THREE‐DIMENSIONAL VISUALIZATION AND VOLUME MEASUREMENTS OF EQUINE PARANASAL SINUSES

The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three-dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2-25 years, were analyzed by the use of separate semi-automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi-automated segmentation of CT-datasets improved understanding of this anatomically challenging region.

Magnetic resonance imaging appearance of the medial wall of the cavernous sinus for the assessment of cavernous sinus invasion by pituitary adenomas

The diagnostic criteria for cavernous sinus invasion (CSI) by pituitary adenomas are still unsatisfactory and controversial. For this reason, the study examined the appearance of the medial wall of the cavernous sinus (MWCS) on proton-density-weighted (PDW) magnetic resonance imaging (MRI) to determine its value for preoperative assessment of CSI. A 3.0-Tesla MRI scanner was used to obtain preoperative PDW images and conventional MRI sequences of 48 consecutive pituitary adenomas, and the MWCS was examined in PDW images to determine the presence of CSI in comparison to surgical findings and three traditional MRI criteria: Knosp grading system (KGS); percentage of encasement of the internal carotid artery (PEICA); and replacement of cavernous sinus compartments (RCSC) by tumors. The value of the MWCS as seen on MRI was compared with that of the Ki-67 labelling index (Ki-67 LI). CSI images showed that continuity of the MWCS was interrupted and that tumor tissue had infiltrated the cavernous sinus (CS) compartments through the defects. In 96 CSs from 48 patients, the sensitivity of MRI visualization of the MWCS for detection of CSI was 93.3% with a specificity of 93.8%, which was significantly higher than with KGS, PEICA and RCSC (P=0.007, P=0.008 and P=0.056, respectively). Histopathological results showed no significant differences between MRI visualization of the MWCS and the Ki-67 LI. PDW imaging permits adequate visualization of the MWCS and is superior to traditional diagnostic criteria for the detection of CSI, providing accurate preoperative images for intraoperative navigation.