Indocyanine green fluorescence visualizes landmark arteries for endoscopic sinus and skull base surgery.

OBJECTIVE: Landmark arteries during endoscopic sinus surgery are currently identified on the basis of anatomy, CT imaging and navigation, and Doppler flowmetry. However, the advantage of intraoperative fluorescence imaging during endoscopic sinus surgery has not been demonstrated. This study aimed to investigate whether Indocyanine Green (ICG) is useful for visualizing landmark arteries during endoscopic sinus and skull base surgery. METHODS: Eight patients who underwent endoscopic sinus and pituitary surgeries and consented to study participation were included. After planned procedures were performed as usual, landmark arteries were examined by ICG endoscope. Recorded video and preoperative CT images were analyzed for identification of five landmark arteries: anterior ethmoidal artery (AEA), posterior ethmoidal artery (PEA), internal carotid artery (ICA), sphenopalatine artery (SPA), and postnasal artery (PNA). Identification of arteries was evaluated three grades: identifiable, locatable, unrecognizable. RESULTS: Eight patients and eleven sides were evaluated. The ICG dose was 2.5 mg/body and a single shot was sufficient for evaluation. 100 % of AEA was identified (9/9 sides), 86 % of PNA (6/7 sides), 56 % of ICA (5/9 sides), and 25 % of PEA and SPA (2/8 sides). CONCLUSION: ICG could visualize landmark arteries, even thin arteries like AEA, during endoscopic sinus and skull base surgeries. Visualization was affected by thickness of bone or soft tissue above arteries, blood clots, sensitivity setting, and angle and distance of near-infrared light irradiation. ICG visualization of landmark arteries may help avoid vascular injuries during endoscopic sinus and skull base surgeries, particularly of AEA, PNA and ICA.

Development of an Experimental Model for Studying the Nasosinusal and Skull Base Arterial and Venous Systems Using Iodinated Contrast and Latex in Cadavers.

BACKGROUND: Cadaver dissection remains one of the most reliable and safest ways to study anatomy, whereas computed tomography angiography (CTA) is an essential technology for enabling students to become familiar with human anatomy and surgical planning. Thus, the convergence of both radiologic and anatomic information is important for surgical success, especially in regions of complex anatomy such as the nasosinusal and skull base regions. Here we propose an experimental model in formalinized cadaver heads consisting of intravascular injection of colored latex and iodinated contrast mixture, followed by CTA scans of the nasosinusal and skull base arterial and venous systems before dissection. METHODS: Six cadaver heads that had been preserved for >5 years in 10% formaldehyde were immersed for 72 hours in a solution containing a dimethyldiethanol mono/dialkyloyl ester quaternary ammonium salt. In 5 of these heads, a mixture composed of latex, tissue ink, and iodinated contrast (Ultravist 300) was injected into the vascular system. CTA scans were performed sequentially after the injection, followed by endonasal and macroscopic dissections. RESULTS: There was good radiologic and macroscopic vessel uptake in 4 specimens, allowing a detailed anatomic study. CONCLUSIONS: An experimental model was made feasible by injecting iodinated contrast and colored latex into formalinized cadavers for CTA evaluation of the nasosinusal and skull base arterial and venous systems before performing dissections.

Venous Abnormalities Leading to Tinnitus: Imaging Evaluation.

Venous anomalies are the most commonly identified abnormality by imaging in the work-up for pulse synchronous tinnitus. Potential diagnoses include idiopathic intracranial hypertension, sigmoid sinus wall anomalies, transverse and sigmoid sinus stenosis, jugular bulb anomalies, and prominent posterior fossa emissary veins. These causes are discussed in detail along with the association between sigmoid sinus wall anomalies and idiopathic intracranial hypertension.

Management of arterial injury during endoscopic sinus and skull base surgery.

PURPOSE OF REVIEW: The most feared complication during endonasal surgery is a carotid artery injury. The sheep model of carotid injury provides training for this event by giving a realistic endoscopic experience of major vascular injuries and tissue hemostasis. RECENT FINDINGS: The sheep model of carotid artery injury recreates the narrow nasal confines and high-flow/high-pressure vascular injury accurately reproducing the endoscopic challenges seen in such vascular emergencies. This has led to the development of surgical techniques that quickly and effectively control the field of bleeding and achieve reliable hemostasis including the crushed muscle patch new direct vascular closure technologies. Vascular emergency simulation training is achieving better outcomes for our patients. SUMMARY: All skull base surgeons are at risk of the unexpected carotid artery injury and recently, the sheep model not only effectively recreates this situation but has identified clinically tried and tested techniques at managing this situation and is improving patient outcomes.

The effect of blood pressure and cardiac output on the quality of the surgical field and middle cerebral artery blood flow during endoscopic sinus surgery.

BACKGROUND: A clear surgical field is critical during endoscopic sinus surgery (ESS). Hypotensive anesthesia and cardiac output (CO) may optimize the surgical field; however, evidence of their effect on bleeding and cerebral blood flow is conflicting. The aim of this study was to evaluate the effect of blood pressure (BP) and CO on intraoperative bleeding and middle cerebral artery blood flow velocity (Vmca ) during ESS. METHODS: This was a prospective randomized controlled trial. Patients undergoing ESS for chronic rhinosinusitis at a tertiary institution in 2013 were randomized to receive BP manipulation using target-controlled noradrenaline infusion during surgery to either their left or right sinuses. The contralateral side in each patient served as control. Bleeding was scored using a 0 to 10 point bleeding assessment scale (BAS, 0-10) and Vmca was measured using transcranial Doppler ultrasonography every 10 minutes or when surgically opportune, and time-matched with BP and CO. Data was analyzed using Bland-Altman methods. RESULTS: A total of 105 time points were collected across a mean arterial pressure (MAP) range of 32 to 118 mmHg. Significant correlations were demonstrated between MAP and Vmca (r = 0.7, p < 0.0001), MAP and BAS (r = 0.50, p < 0.0001), CO and Vmca (r = 0.57, p < 0.0001), and CO and BAS (r = 0.42, p < 0.0001). The best surgical fields were seen at 40 to 59 mmHg MAP. However, MAP below 60 mmHg produced >50% reduction in Vmca in more than 10% of time points. CONCLUSION: Balancing surgical visibility with organ perfusion remains a challenge. The results of this study show that moderate hypotension significantly improves the surgical field; however reducing BP below 60 mmHg may risk cerebral hypoperfusion.

Searching for the cheese: does ethmoid pneumatization affect the location of the anterior ethmoid artery?

Endoscopic sinus surgery is a widely used technique in otolaryngologic practice. To avoid complications, the locations of important anatomical structures, such as the anterior ethmoid artery (AEA), should be determined preoperatively. We want to evaluate the effect of ethmoid cavity pneumatization on the location of the AEA and to determine consistent landmark(s) for locating the AEA. 524 consecutive patients undergoing sinus CT scans between February and October 2012 were reviewed retrospectively. After the exclusion criteria were applied, 150 CT scans (300 sides) were selected for the study. A statistically significant positive correlation was found between ethmoid pneumatization and the distance of the AEA to the attachment of the inferior turbinate to the lateral nasal wall (Spearman's rho = 0.305; p < 0.001). Likewise, a statistically significant positive correlation was found between ethmoid pneumatization and the distance between the AEA and the frontonasal junction (Spearman's rho = 0.219; p < 0.001). We found that the artery was located mostly between the second and third lamellae [n 211 (71 %) cases]. There was no statistically significant correlation between ethmoid pneumatization and AEA location in terms of the lamellae. Increased ethmoid volume increases the distance of the AEA from the frontonasal junction and the lateral attachment of the inferior turbinate. However, increased pneumatization of the ethmoid cavity did not affect AEA localization in terms of the lamellae. Based on our findings, we suggest that using the lamellae to locate the AEA is reliable.

Intravenous tranexamic acid and intraoperative visualization during functional endoscopic sinus surgery: a double-blind randomized controlled trial.

BACKGROUND: Bleeding during endoscopic sinus surgery (ESS) can hinder surgical progress and may be associated with increased complications. Tranexamic acid is an antifibrinolytic that is known to reduce operative bleeding. The current study was designed to assess the effect of adjunctive intravenous tranexamic acid on intraoperative bleeding and the quality of the surgical field during ESS. METHODS: Double-blind, randomized, controlled trial. Patients undergoing ESS for the primary diagnosis of chronic rhinosinusitis with or without polyposis were included. Sample size calculation based on a clinically relevant difference in the Wormald surgical field score yielded a sample of 28. In addition to standard measures to minimize blood loss, study patients received intravenous tranexamic acid with control patients receiving intravenous normal saline. Outcome measures included the Wormald grading scale to assess the intraoperative surgical field and estimated blood loss based on suction container contents with irrigation fluid subtracted. RESULTS: Twenty-eight patients (median age, 45 years; range, 23-80 years) were included in the study. Diagnoses included chronic rhinosinusitis without polyposis (n = 5), chronic rhinosinusitis with polyposis (n = 23). The use of the tranexamic acid was not associated with a statistically significant decrease in estimated blood loss (201 vs 231 mL; p = 0.60) or Wormald grading scale (5.84 vs 5.80; p = 0.93). There were no adverse events or complications during the study. CONCLUSION: Adjunctive intravenous tranexamic acid does not appear to result in a clinically meaningful reduction in blood loss or improve visualization of the surgical field during ESS.

Pilot study comparing total intravenous anesthesia to inhalational anesthesia in endoscopic sinus surgery: novel approach of blood flow quantification.

OBJECTIVES: We compared anesthesia with sevoflurane-remifentanil hydrochloride (SR) to total intravenous anesthesia with propofol-remifentanil hydrochloride (PR) in patients undergoing endoscopic sinus surgery for chronic rhinosinusitis in terms of sinonasal mucosal blood flow, the surgical field visualization score, and blood loss. METHODS: We performed a double-blinded prospective study at a tertiary care center in 23 adults scheduled to undergo endoscopic sinus surgery for chronic rhinosinusitis. The patients were randomized to receive SR or PR. The sinonasal mucosal blood flow was measured by optical rhinometry. The surgical field visualization score was based on the Boezaart scale. RESULTS: The groups had similar clinical characteristics. During the 60- to 90-minute and 90- to 120-minute operative time windows, the blood flow was significantly greater in the PR group than in the SR group (p = 0.04 and p = 0.03, respectively). The amounts of blood loss in the PR and SR groups were 152.9 +/- 161.3 mL and 355.9 +/- 393.4 mL, respectively (p = 0.12). The median ratios of the surgical field visualization score to the number of sinuses operated on in the PR and SR groups were 2.1 and 1.8, respectively (p = 0.52). CONCLUSIONS: The intraoperative blood flow, as determined by optical rhinometry, was significantly greater with anesthesia with PR than with anesthesia with SR, 1 hour into the procedure; however, this difference did not translate into differences in the amounts of operative blood loss or in the surgical field visualization scores.

Sinonasal perivascular epithelioid cell tumor: benign or malignant neoplasm?

BACKGROUND: Neoplasms showing perivascular epithelioid cell differentiation (PEComas) are uncommon tumors of the sinonasal tract. They are often misdiagnosed as angiomyolipoma or a simple benign tumor or polyp. We present a further case of a sinonasal PEComa and review the literature in an attempt to ascertain their malignant potential. METHODS: Published evidence on invasiveness and characteristics were defined on systematic review. MEDLINE and EMBASE were searched from 1966 and 1980, respectively, to week 3 of December 2010. Publications reporting PEComa or angiomyolipoma were sought. Only those describing a sinonasal origin were included. Demographics, anatomic site, local invasion, recurrence rates, and mortality were recorded. A case report of a locally invasive intranasal PEComa is described. RESULTS: In addition to the case we present, 12 case reports were located (n = 13). The mean age of patients was 59.6 (SD, 14.98 years) years. The location was within the right sinonasal tract in 54% of cases, the left sinonasal tract in 38% of cases, and not reported in 8% of cases. Treatment focused on local surgical excision and this was achieved endoscopically in 100% of cases. Recurrence rate was 8%. Mean follow-up was 17.4 (SD, 20.68 months) months. Invasion was noted in 23% of cases. There was a single death recorded. CONCLUSION: PEComas of the paranasal sinuses and skull base appear to have a biological behavior different from simple benign angiomyolipomas reported elsewhere in the body. PEComa may be more intermediate or malignant in clinical behavior.

Is there any relationship between the frontal cell and the Agger nasi cell and the localization of the anterior ethmoid artery?

OBJECTIVES: In this article, we examined the effect of the presence or absence of a frontal cell or an Agger nasi cell on the localization of the anterior ethmoid artery. PATIENTS AND METHODS: Coronal paranasal sinus computed tomography scans on 110 sides of 61 patients (35 males, 26 females; mean age 35.6 ± 12.7 years; range 15 to 72 years) who underwent surgery for septal deviation, concha bullosa, antrochoanal polyp between September 2006 and February 2008 were retrospectively evaluated and the anterior ethmoid foramen localization was measured according to the anterior nasal spine. The correlations of these measurements with the presence and absence of a frontal cell and an Agger nasi cell were investigated. RESULTS: The measurement of the anterior ethmoidal foramen according to anterior nasal spine was 18.2 ± 8.8 mm in the absence of an Agger nasi cell and was 20.3 ± 6.6 mm in the presence of an Agger nasi cell. This distance was measured as 20.0 ± 7.3 mm when the frontal cell was not determined. This measurement was 20.2 ± 6.5 mm in the presence of a frontal cell. According to the frontal cell types the results of the measurements were 20.5 ± 5.9 mm, 18.9 ± 8 mm, 20.6 ± 7.3 mm, for type 1, type 2 and type 3, respectively. Our results revealed that there were no significant relationship between the presence or absence of a frontal cell and an Agger nasi cell and the localization of the anterior ethmoidal foramen. CONCLUSION: The results of this study showed that the presence or absence of these cells does not affect localization of the anterior ethmoid artery.

Human paranasal sinuses and selective brain cooling: a ventilation system activated by yawning?

The function of the paranasal sinuses has been a controversial subject since the time of Galen, with many different theories advanced about their biological significance. For one, the paranasal sinuses have been regarded as warmers of respiratory air, when in actuality these structures appear to function in cooling the blood. In fact, human paranasal sinuses have been shown to have higher volumes in individuals living in warmer climates, and thus may be considered radiators of the brain. The literature suggests that the transfer of cool venous blood from the paranasal sinuses to the dura mater may provide a mechanism for the convection process of cooling produced by the evaporation of mucus within human sinuses. In turn, the dura mater may transmit these temperature changes, initiated by the cool venous blood from the heat-dissipating surfaces of the sinuses, to the cerebrospinal fluid compartments. Furthermore, it has recently been demonstrated in cadaveric dissections that the thin bony posterior wall of the maxillary sinus serves as an origin for both medial and lateral pterygoid muscle segments, an anatomic finding that had been previously underappreciated in the literature. The present authors hypothesize that the thin posterior wall of the maxillary sinus may flex during yawning, operating like a bellows pump, actively ventilating the sinus system, and thus facilitating brain cooling. Such a powered ventilation system has not previously been described in humans, although an analogous system has been reported in birds.

The efficacy of a novel chitosan gel on hemostasis and wound healing after endoscopic sinus surgery.

BACKGROUND: Postoperative bleeding and adhesion formation are the two most common complications after endoscopic sinus surgery (ESS). Continued bleeding risks airway compromise from the inhalation of blood clots and from the aspiration of blood-stained vomitus. Additionally, adhesion formation is the most common reason for patients requiring revision surgery. This study aimed to determine the efficacy of a novel chitosan/dextran (CD) gel on hemostasis and wound healing after ESS. METHODS: A randomized controlled trial was performed involving 40 patients undergoing ESS for chronic rhinosinusitis. Immediately after surgery a baseline Boezaart Surgical Field Grading Scale was taken. Computer randomization was performed with one side receiving CD gel and the other side receiving no treatment (control). Boezaart bleeding scores were then calculated for each side every 2 minutes. Patient's endoscopic features of wound healing were assessed at 2, 6, and 12 weeks after surgery. RESULTS: CD gel achieved rapid hemostasis with the mean time to hemostasis at 2 minutes (95% CI, 2-4 minutes) compared with 10 minutes (95% CI, > or =6 minutes) for the control (p < 0.001). There were significantly less adhesions at all time points with CD gel versus control: 2 versus 18 at 2 weeks (p < 0.001), 3 versus 16 at 6 weeks (p < 0.001), and 2 versus 12 at 3 months (p < 0.001). There was no significant difference between CD gel and control with respect to crusting, mucosal edema, infection, or granulation tissue formation. CONCLUSION: CD gel is rapidly hemostatic immediately after ESS and prevents adhesion formation, addressing two of the most common complications of sinus surgery.

Anterior ethmoidal artery evaluation on coronal CT scans.

UNLABELLED: The anterior ethmoidal artery (AEA) is an important point for frontal and ethmoid sinuses surgery. CT scans can identify landmarks to help the surgeon find the AEA. AIM: To identify the landmarks of the AEA on the orbital medial wall and on the lateral wall of the olfactory fossa. and to correlate the presence of supraorbital ethmoidal cells with spotting the anterior ethmoidal artery canal. MATERIALS AND METHODS: Retrospective review of 198 direct coronal paranasal sinuses computed tomography (CT) scans from August to December, 2006. RESULTS: Supraorbital pneumatization was seen in 35% (70 scans). The AEA canal was seen in 41% (81 scans). The anterior ethmoidal sulcus was seen in 98% (194 scans) and the anterior ethmoidal foramen was seen in all the scans (100%). CONCLUSION: The anterior ethmoidal foramen and the anterior ethmoidal sulcus were anatomical landmarks present in almost 100% of the scans studied. There was a correlation between the presence of supraorbital pneumatization and AEA canal visualization.

Fungal rhinosinusitis: a categorization and definitional schema addressing current controversies.

BACKGROUND: Fungal (rhino-) sinusitis encompasses a wide spectrum of immune and pathological responses, including invasive, chronic, granulomatous, and allergic disease. However, consensus on terminology, pathogenesis, and optimal management is lacking. The International Society for Human and Animal Mycology convened a working group to attempt consensus on terminology and disease classification. DISCUSSION: Key conclusions reached were: rhinosinusitis is preferred to sinusitis; acute invasive fungal rhinosinusitis is preferred to fulminant, or necrotizing and should refer to disease of <4 weeks duration in immunocompromised patients; both chronic invasive rhinosinusitis and granulomatous rhinosinusitis were useful terms encompassing locally invasive disease over at least 3 months duration, with differing pathology and clinical settings; fungal ball of the sinus is preferred to either mycetoma or aspergilloma of the sinuses; localized fungal colonization of nasal or paranasal mucosa should be introduced to refer to localized infection visualized endoscopically; eosinophilic mucin is preferred to allergic mucin; and allergic fungal rhinosinusitis (AFRS), eosinophilic fungal rhinosinusitis, and eosinophilic mucin rhinosinusitis (EMRS) are imprecise and require better definition. In particular, to implicate fungi (as in AFRS and EMRS), hyphae must be visualized in eosinophilic mucin, but this is often not processed or examined carefully enough by histologists, reducing the universality of the disease classification. A schema for subclassifying these entities, including aspirin-exacerbated rhinosinusitis, is proposed allowing an overlap in histopathological features, and with granulomatous, chronic invasive, and other forms of rhinosinusitis. Recommendations for future research avenues were also identified.

Endoscopic anatomy of the petrous segment of the internal carotid artery.

BACKGROUND: Exposure of the petrous (C2) segment of the internal carotid artery (ICA; petrous carotid) is necessary to treat lesions that have spread from the intracranial space or adjacent sinonasal region. Recent advancements in endonasal-endoscopic approaches to the anterior skull base raise the possibility of extending these approaches beyond the sinonasal cavity. In this cadaveric study, we evaluate the feasibility and extent of exposure of the petrous carotid artery via a combined endoscopic endonasal approach. METHODS: Endoscopic dissection was performed in four formalin-fixed cadaver heads (eight sides). An endoscopic, endonasal, transmaxillary approach was used to identify the cervical and petrous carotid artery. RESULTS: With the endoscopic endonasal, Caldwell-Luc approach, we could visualize the ventral petrous bone after dissecting the contents of the pterygopalatine fossa and infratemporal fossa. Careful dissection allowed exposure of the petrous carotid artery from the upper cervical carotid to the foramen lacerum. CONCLUSION: In this cadaveric study using an endoscopic endonasal approach for exposure of the petrous carotid artery, combination with the transmaxillary-transpterygopalatine-transinfratemporal approaches permitted exposure of the ventral portion of the artery. The anatomy presented will assist experienced endoscopic skull base surgeons in the removal of lesions involving the ventral skull base.

Avaliação da artéria etmoidal anterior pela tomografia computadorizada no plano coronal / Anterior ethmoidal artery evaluation on coronal CT scans

O conhecimento da localização da artéria etmoidal anterior (AEA) constitui etapa importante na cirurgia do recesso do seio frontal e do etmóide anterior. A tomografia computadorizada (TC), em especial no plano coronal pode fornecer reparos anatômicos que identificam o trajeto da AEA. Objetivo: Identificar os reparos anatômicos que caracterizamo trajeto da AEA na parede medial da órbita e na parede lateral da fossa olfatória. Verificar a correlação entre a presença de pneumatização supra-orbitária e a visualização do etmoidal anterior (canal da AEA). Casuística e Métodos: Estudo retrospectivo de 198 tomografias computadorizadas dos seios paranasais no plano coronal do período de agosto a dezembro de 2006. Resultados: Pneumatização supra-orbitária foi identificada em 35% (70 exames). O canal da AEA foi caracterizado em 41% (81 exames). O sulco etmoidal anterior foi visualizado em 98% (194 dos exames) e o forameetmoidal anterior foi identificado em todos os exames (100%). Conclusão: O forame etmoidal anterior e o sulco etmoidal anterior foram referências anatômicas presentes em quase 100% dos exames avaliados. Houve correlação entre a presença de pneumatização supra-orbitária e a caracterização do canal da AEA.

The anterior ethmoidal artery (AEA) is an important point for frontal and ethmoid sinuses surgery. CT scans can identify landmarks to help the surgeon find the AEA. Aim: To identify the landmarks of the AEA on the orbital medial wall and on the lateral wall of the olfactory fossa. and to correlate the presence of supraorbital ethmoidal cells with spotting the anterior ethmoidal artery canal. Materials and Methods: Retrospective review of 198 direct coronal paranasal sinuses computed tomography (CT) scans from August to December, 2006. Results: Supraorbital pneumatization was seen in 35% (70 scans). The AEA canal was seen in 41% (81 scans). The anterior ethmoidal sulcus was seen in 98% (194 scans) and the anterior ethmoidal foramen was seen in all the scans (100%). Conclusion: The anterior ethmoidal foramen and the anterior ethmoidal sulcus were anatomical landmarks present in almost 100% of the scans studied. There was a correlation between the presence of supraorbital pneumatization and AEA canal visualization.

Nitric oxide and the paranasal sinuses.

The discovery within the paranasal sinuses for the production of nitric oxide (NO) has altered the traditional explanations of sinus physiology. This review article reports the ongoing investigation of sinus physiology beginning with the discovery of NO gas production in the paranasal sinuses that occurred in 1995, and the impact that finding has had both in the basic science and clinical arenas. It was shown that healthy paranasal sinus epithelium expresses an inducible NO synthase that continuously generates large amounts of NO, a pluripotent gaseous messenger with potent vasodilating, and antimicrobial activity. This NO can be measured noninvasively in nasally exhaled breath. The role of NO in the sinuses is likely to enhance local host defense mechanisms via direct inhibition of pathogen growth and stimulation of mucociliary activity. The NO concentration in a healthy sinus exceeds those that are needed for antibacterial effects in vitro. In patients with primary ciliary dyskinesia (PCD) and in cystic fibrosis, nasal NO is extremely low. This defect NO generation likely contributes to the great susceptibility to chronic sinusitis in these patients. In addition, the low-nasal NO is of diagnostic value especially in PCD, where nasal NO is very low or absent. Intriguingly, NO gas from the nose and sinuses is inhaled with every breath and reaches the lungs in a more diluted form to enhance pulmonary oxygen uptake via local vasodilation. In this sense NO may be regarded as an "aerocrine" hormone that is produced in the nose and sinuses and transported to a distal site of action with every inhalation.

[Avoiding and dealing with bleeding during endoscopic sinus surgery]. / Vermeidung von und Umgang mit Blutungen während endoskopischer Nasennebenhöhlenchirurgie.

Endoscopic sinus surgery is one of the most frequent surgical ENT-procedures. Bleeding during surgery may increase complications and may have negative effects on surgery and outcome. The present paper describes strategies to prevent and deal with bleeding during sinus surgery. Preoperative conservative treatment of mucosal inflammation as well the use of adrenalin for decongestion may reduce intraoperative bleeding and hence complications.