Ent Trends- Issue 1, July 2009

TRYST WITH

HISTORY

ISSUE 1

VOLUME 1

J U L Y 2009


FUNGAL SINUSITIS: RECENT TRENDS


QUIZ

E– NEWSLETTER ON RECENT TRENDS IN ENT

ENT trends

Fungal sinusitis Issue 1 TRYST WITH HISTORY ALLERGIC FUNGAL RHINOSINUSITIS FUNGAL SINUSITIS: CURRENT TRENDS RADIOLOGY OF FUNGAL SINUSITIS JOURNAL SCAN QUIZ

© Dr. Pooja Kataria, New Delhi, July 2009

Foreword

Dear colleagues, Being an academician for more than twenty years, I have witnessed the ever changing scenario of teaching and acquiring knowledge. We have come a long way from attending lectures, flocking the libraries to now, virtually sitting at home and getting all the information at click of a button. Shaking hands with the technological advancement and to further our knowledge of Otorhinolaryngology, we have decided to launch a newsletter. Each issue of this e- newsletter will focus on a particular topic of clinical or academic importance and will touch upon everything, from historical aspects to the recent trends. The success of this endeavor will depend on your contributions and feedback. This concept is originated by youngsters and should be encouraged. I hope that this will receive all your support and guidance. I wish the editors and authors the best of luck and congratulate them for their effort.

DR. A. K. AGARWAL Dean and Director Professor ENT, Maulana Azad Medical College

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ENT

TODAY

VOL. 1, ISSUE1. JULY 2009 E- NEWSLETTER ON RECENT Modern practice of medicine offers vast information on every topic, but on the downside confuses us with multitude of treatment options. Experience coupled with our knowledge on a particular topic gathered from our institutions or otherwise, guides us through the proper management. Keeping abreast with the ongoing research and ever changing therapeutic guidelines, we have taken upon us the task to compile a newsletter. Our attempt will be to outline the national and international treatment guidelines along with the recent trends on a particular disease, in each issue. Through this e-newsletter, our humble effort is to interact with as many ENT surgeons and expand our knowledge pool with their feedback.

We hope you enjoy reading this issue as much as we did compiling it. This issue focuses on the controversial topic of fungal sinusitis and its debatable management. We plan to take out the next issue on some interesting ear topic, may be the illustrious “cochlear implant”:) Since in medicine, there is one rule that there is no rule, inputs from varied sources will lead to enrichment of our skills, particularly of those graduates who are in the formative stages of their career. We solicit contributions from as many ENT practitioners, and sincerely hope that this e-newsletter will grow with each passing day.

E-Mail: [email protected] Advisor Dr. A.K. Agarwal Editorial Board Pooja Kataria Sumit Mrig Ankush Sayal

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Tryst with History History has never fascinated us medicos, but of course we like to know how and when great minds discovered the techniques and equipment we use today. The most significant advances in medicine in this century have been the discovery of antibiotics, the invention of various computerized scans and endoscopy of the various body cavities. The first revolutionary change in the surgical treatment of the sinuses was the introduction and refinement of endoscopic techniques. The second important development in the modern history of rhinology was the introduction of powered instrumentation. Now we are seeing a third turning point, which is the use of intraoperative image guidance in endoscopic sinus surgery. Endoscopes are used in many branches of medicine today, so much so, there is no body cavity one cannot have a look into. The endoscopes used for nasal sinus endoscopy are rigid tubes consisting of rod lenses. The optical system used has been developed by Prof. H.H.Hopkins has larger viewing angles and transmit brighter light. Special instruments developed for the purpose are passed alongside the endoscope into the nose and operations are carried out using key hole surgery principle. Though the idea was conceived and early work was done by Prof. Messerklinger of Graz, Austria, it is Prof.H.Stammberger who popularized Endoscopic sinus surgery in the English speaking world. The radical Endoscopic spheno-fronto-maxillo -ethmoidectomy we do for massive polyps and fungal sinusitis would not fit into the original description of FESS by Dr. Kennely and Prof. Stammberger. Hence it is referred to as Endoscopic Sinus Surgery (ESS). The first powered instrument (microdebrider, or soft tissue shaver) was designed and patented by an Otolaryngologist, Dr. J.C. Urban, in 1969, for use in microscopic ear surgery. Powered instruments became very useful in orthopedic arthroscopic surgery in the 1970s and were used in OtolaryngologyHead & Neck Surgery in the 1990s, after the introduction of endoscopic techniques made their use more practical. Reuben Setliff was the first physician to successfully demonstrate that powered cutting tools could be used with precision control and safety in the nose and paranasal sinuses in humans. The first MicroDebrider was adapted from a tool produced for use in small joint arthroscopy in the wrist and TMJ.

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Allergic fungal rhinosinusitis

History: The combination of nasal polyposis, crust formation, and sinus cultures yielding Aspergillus was first noted in 1976 by Safirstein who observed the clinical similarity that this constellation of findings shared with allergic bronchopulmonary Aspergillosis ( ABPA). In 1981, Millar et al described five cases of chronic Aspergillus fumigatus sinusitis in which the sinus exudates appeared histologically similar to the inspissated bronchial mucus plugs in patients with ABPA. The authors named the condition “allergic aspergillosis of the paranasal sinuses”. In 1983, Katzenstein and colleagues retrospectively reviewed 113 consecutive surgical histopathologic specimens from chronic sinusitis surgeries. Seven (6%) were identified as “allergic aspergillus sinusitis”. Histologically the extramucosal material was characterized as “allergic mucin”- degenerating eosiniphils, desquamated respiratory epithelial cells, and Charcot-Leyden crystals. Fungal stains showed fungal hyphae in the allergic mucin, but not in the mucosa. There was no histologic evidence for tissue invasion by the fungi. Many others also reported identical findings thereafter and more cases have been described since then, not only with Aspergillus spp. but with other fungi such as Bipolaris, Alternaria, Curvilaria, and Exserohilum. Allergic fungal sinusitis (or allergic fungal rhinosinusitis; AFRS) is a term introduced by Robson et al in 1989.

One popular theory proposed by Manning and colleagues is based on the assumption that AFRS exists as nasal correlate of allergic bronchopulmonary aspergillosis, of the disease. It is depicted in a diagrammatic representation on the next page. At some point this cycle becomes selfperpetuating and results in the eventual product of this process: allergic mucin; accumulation of which obstructs the involved sinuses and propagates the process. Certain unanswered questions regarding this theory • If AFRS is an IgE mediated disease, then why does it predominantly occur in a unilateral fashion • Why does fungal specific IgE remain elevated after prolonged fungal immunotherapy when normally it should decrease? Hence, although it remains clear that the eosinophils play an important role in the development of AFRS; eosinophilic inflammation may occur as a final common pathway in response to a number of different inflammatory starting points.

Clinical presentation: Patients typically present with • gradual nasal airway obstruction and production of semisolid nasal crusts that, on inquiry, match the gross description of allergic fungal mucin. Comparision to ABPA • The development of nasal obstruction may have been AFRS is believed to have an etiology similar to that of so gradual that the patient is unaware of its presence. ABPA. As more is understood about the pathophysiology of • Pain is uncommon among patients with AFRS and ABPA than AFRS, the former is discussed as possible suggests the concomitant presence of a bacterial model for the processes involved in AFRS. rhinosinusitis. These diseases are initiated by immunological reactivity to • Patients with AFRS are atopic but generally have antigens of Aspergillus species in the sinuses or bronchi of been unresponsive to antihistamines, intranasal cortiaffected individuals; and may be components of a wide costeroids, and prior therapy. The use of systemic spectrum of compartmental allergic manifestations in the corticosteroids may produce some relief of symprespiratory tract. toms, but relapse typically follows completion of therapy. Pathophysiology: Physical findings on examination, range from nasal The exact pathophysiology of AFRS remains a matter of obstruction to gross facial disfigurement and orbital or conjecture for which several theories have been offered. ocular abnormalities.

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Initiation of inflammatory cascade leading to AFRS is a multifactorial event -

Local

Genetic

Environmental

-mucostasis -anatomic anomaly

-Fungal exposure

Exposure

Anatomic factors

-Atopy -T-lymphocyte susceptibility

Nasal saline irrigation

Fungal Proliferation Antigenic exposure

s u r g e r y

Edema

Obstruction Stasis Decreased ventilation

Inflammatory trigger

Allergic mucin

Gel & Coombs TypeI & III T– Cell Others

Immunotherapy Steroids

Bacterial infection

Inflammation Eosinophilic inflammation MBP, ECP, etc)

P.S: block arrows indicating points of intervention to break the cycle

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Radiologic findings:

Soft tissue attenuation areas with internal hyperdensity are seen on non-contrast CT scans. These findings are although not specific for AFRS, but they are relatively characteristic and provide preoperative information supportive of the diagnosis of AFRS. The ethmoid sinus is the most commonly involved sinus, whereas the lamina papyracea is the most common bone to exhibit demineralization. The presence of accumulations of heavy metals (iron, manganese) and calcium salt precipitation within the inspissated allergic mucin is the most likely cause of these radiologic findings. On MRI, presence of hypointense central T1 signal, central T2 signal void, and increased peripheral T1/T2 enhancement is highly specific for AFRS as compared with other forms of fungal sinusitis. The high protein and low water concentration of allergic fungal mucin, coupled with the high water content within surrounding edematous paranasal sinus mucosa, gives rise to specific MR characteristics. Laboratory findings: Immunologic tests: Total IgE levels is a useful indicator of AFRS clinical activity. It is generally elevated to more than 1000 U/ml. Patients usually demonstrate positive skin test and in vitro ( RAST) responses for both fungal and nonfungal antigens. Histology of allergic fungal mucin: Allergic mucin is the hallmark of this disease. Grossly, it is thick, tenacious, and highly viscous in consistency; its color may vary from light tan to brown or dark green. Histologic examination reveals branching noninvasive fungal hyphae within sheets of eosinophils and Charcot-Leyden crystals. Culture of fungi: Fungal cultures provide some supportive evidence helpful in diagnosis and subsequent treatment of AFRS, but it is important to realize that the diagnosis of AFRS is not established or eliminated on the results of these cultures. Various species of fungi have been cultured including Bipolaris, Curvalaria, Aspergillus, Exserohilum and Alternaria.

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Diagnosis: Although certain signs and symptoms , as well as radiographic, intraoperative, and pathologic findings, may cause the physician to suspect allergic fungal sinusitis, no standards had been defined for establishing the diagnosis. Parameters which enhanced the index of suspicion were as stated by Waxman et al (laryngoscope 1987): (1)Young adults, (2)Recurrent polyposis, (3)History of asthma, (4)Multiple affected sinuses, (5)History of poor response to medical management, (6)Multiple surgical procedures, (7)Thick inspissated intracavity mucus, (8) Atopic patients with nasal polyps. Many others used the combination of radiologic, laboratory and histologic parameters to distinguish AFRS from other forms of rhinosinusitis. In 1996, Bent and Kuhn laid down the diagnostic criteria, which are the most widely accepted. These are as follows: • •

• • • • • • • • •

Type I hypersensitivity confirmed by history, skin tests, or serology Nasal polyposis Characteristic CT signs- serpiginous areas of increased attenuation within the sinus cavity. Eosinophilic mucin without fungal invasion Positive fungal stain Asthma Unilateral predominance Radiographic bone erosion Positive fungal culture Charcot-Leyden crystals Peripheral eosinophilia

M A J O R

M I N O R

Of the criteria mentioned, allergic or eosinophilic mucin and atopy (Type I hypersensitivity) are considered the most diagnostic of all. Treatment: Long term control of AFRS requires both elimination of fungal antigen by surgical therapy and control of its recurrence by medical therapy. As early as 1979, it was established by McGuirt et al, that the treatment of paranasal sinus aspergillosis is surgical and the key to which is the removal of diseased mucosa and aeration and drainage of the involved sinus. Previously, procedures such as open antrostomies, intranasal sphenoethmoidectomies, lateral rhinotomies, and craniofacial resection were done. More radical procedures were also being done because the clinical and radiographic evidence of invasion into adjacent spaces, were interpreted as evidence of malignancy or invasive fungal disease. And hence, more morbidities and mortalities were encountered. Changes have evolved in both medical and surgical arms of therapy. Radical surgery for AFRS has given way to more conservative, tissue-sparing techniques, “conservative, but complete” as proposed by Mabry et al.

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Preoperative therapy: It is accepted that to decrease intranasal inflammation and nasal polyp volume, systemic prednisolone (0.5 to 1.0 mg/kg/day) should be started 7 days before surgery. Preoperative antibiotics should also be instituted because of the frequency of concomitant postobstructive bacterial sinusitis. Goals of surgical treatment: Surgery should result in complete extirpation of all allergic mucin and fungal debris, reducing or eliminating the antigen-inciting factor within the atopic individual. Polyps can provide an important intraoperative role by serving as a marker of disease. • Second goal of the surgery is to provide permanent drainage and ventilation of the affected sinuses while preserving the integrity of underlying mucosa. • Final goal of the surgery is to provide postoperative access to the previously diseased areas, as even under ideal conditions, some residual fungus may remain in situ inciting recurrence if not controlled postoperatively. •

Medical therapy: Corticosteroids: Topical corticosteroids are accepted as standard therapy in postoperative treatment of AFRS, but they possess a limited benefit before surgery because nasal access is restricted. Kupferberg et al refined the endoscopic follow-up into a staging system, which allows closer control of the mucosal response to medical management, that is, oral steroids. Oral prednisone (0.4 mg/kg per day)- 4 days reduction by 0.1 mg/kg/day in cycles of 4 days Oral prednisone 20 mg/day, or 0.2 mg/kg/day (whichever is greater)- 1 month Oral prednisone 0.2 mg/kg/day monthly follow-ups with nasal endoscopy and serum IgE levels

Dose adjusted based on maintenance of Stage 0- 4 months

STAGING SYSTEM BASED ON ENDOSCOPIC FINDINGS

0 no mucosal edema or allergic mucin I mucosal edema with or without allergic mucin II polypoid edema with or without allergic mucin III sinus polyps with fungal debris or allergic mucin

Oral prednisone at 0.1 mg/kg/day plus intranasal steroid spray at triple dose- one spray in each nostril 3 times daily patient maintained at Stage 0 for 2 months Oral prednisone tapered to zero, intranasal steroid spray continued for 1 year Follow up till 5 years : endoscopy and serum IgE levels monthly for 6 months, bimonthly for 3-5 years.

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Antifungals: In vitro studies of use of oral antifungals show promising results in AFRS, but in vivo studies are pending. However, the expense, limited available data, and potential drug-related morbidity of systemic antifungal therapy may limit the usefulness of this form of treatment for noninvasive fungal disease. Topical application of antifungal agents may hold some benefit in the control of postoperative recurrence. A study by Fenna et al (Laryngoscope February 2009), examined the effect of topical Amphotericin B on inflammatory markers in patients with chronic rhinosinusitis, and concluded that it has no significant effect on activation markers of nasal inflammatory cells. Immunotherapy: The similarity between AFRS and ABPA led to a theoretical concern that immunotherapy using specific fungal antigens in patients with either of these diseases might incite further allergic reactions by adding to the patient’s fungal antigenic stimulus and possible exacerbation of immune complex development and deposition. However, in the case of AFRS, surgery theoretically allows removal of the inciting fungal load from the paranasal sinuses and hence, immunotherapy after surgery may be beneficial rather than harmful. Surgical exenteration of sinuses + confirmation of diagnosis

Allergy evaluation and testing( RAST and quantitative skin tests) for relevant fungal and non-fungal antigens appropriate for the area. Avoidance measures Treatment protocol explained to patient Pharmacotherapy Informed consent adjusted One vial prepared of all positive non-fungal antigens Second vial of all positive fungal antigens (vial test with each performed)

Weekly immunotherapy placing one injection from each vial in a different arm (for accurate recognition of cause of any local reactions)

dose advancement as tolerated, patient observed for local reactions, adverse changes in nasal signs/symptoms, adjustment of medical management based on endoscopic examination for re-accumulation of allergic mucin or reformation of polyps

Immunotherapy continued for about 3-5 years.

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Follow-up • •

•

Postoperatively for at least 3 years. Postoperative treatment with oral corticosteroids, topical steroid nasal sprays, antihistaminics and decongestants (if indicated), anti-leukotrienes ( may be!?) and nasal sinus lavage are followed. Allergen immunotherapy if available is started as detailed. Postoperative follow-up includes monitoring changes in clinical status and serial measurements of total serum IgE which in-turn guide the dose changes of oral corticosteroids and addition of antibiotics, if needed. Progressive decrease in total serum IgE levels is a good prognostic sign, that encourages prednisone tapering according to protocol. A progressive rise in total serum IgE levels during follow-up, or a rise that occurs repeatedly during attempted prednisone tapers should alert the clinician to probable recurrent surgical AFRS and the need for additional surgical evaluation.

Goals to be achieved • • •

To keep clinical rhinosinusitis minimal and forestall the need for recurrent sinus surgery. To taper oral corticosteroids without significant worsening of condition. To minimize treatment related steroid side effects.

Author details: Dr. Pooja Kataria, Specialist, ESI Hospital, Basaidarapur, New Delhi.

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Fungal sinusitis: current trends AND ONGOING RESEARCH The following section will give you a brief overview of what’s latest in management of fungal sinusitis. We will try to highlight newer, amazing discoveries and tickle your brains to explore the topics in detail :)

The classification which is currently being followed for fungal sinusitis is proposed by de Shazo et al: Syndrome

Common causes

Host character- Associated con- Histopathologi- Clinical presenistics ditions cal findings tation

Treatment

Prognosis

Allergic fungal rhinosinusitis

Bipolaris Species, Curvularia lunata & Aspergillus fumigatus

Immunocompe- Chronic tent, frequently rhinosinusitis, atopic nasal polyps

Eosinophil-rich Chronic pansimucoid material nusitis nasal (allergic mucin) polyps, proptosis or eye– muscle entrapment in children

Debridement, Recurrence aeration, oral common and topical corticosteroids, ? immunotherapy

Sinus fungal ball (mycetoma)

A. fumigatus and A. flavus

Immunocompe- Chronic rhinosinusitis tent

Dense accumulation of fungal elements in a mucoid matrix

Rhinosinusitis ( often U/L), Nasal obstruction, greenbrown nasal discharge

Debridement, aeration, antifungal agents not required

Excellent

Acute invasive fungal rhinosinusitis

Mucorales and Aspergillus

Immunocompromised, rarely immunocompetent

Fungal elements in mucosa, submucosal, blood vessels or bone, extensive tissue necrosis

Fever, cough, crusting of nasal mucosa, epistaxis, headache, mental status change

Radical debridement until histologically normal tissue is evident, antifungal agents, treatment of underlying conditions

Fair when disease is limited to sinus, poor with intracranial involvement

Chronic invasive fungal rhinosinusitis

A. fumigatus

Immunocompe- Diabetes tent mellitus

Necrosis of mucosa, submucosal, bone & blood vessels, low grade inflammation

Orbital apex syndrome, nerve palsy

Radical debride- Variable, longment, antifungal term survey agents required

Granulomatous A. flavus invasive fungal rhinosinusitis

Immunocompe- None tent

Granulomas Unilateral propwith multinucle- tosis ate giant cells, histiocytes

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Diabetes mellitus, malignant conditions, Immunosuppressive therapy

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Debridement, aeration, and antifungal agents

Good, but disease can recur

Advances in treatment The triazoles are newer, and are less toxic and more effective: • Fluconazole • Itraconazole • Ravuconazole • Posaconazole • Voriconazole Newer recommendations for treatment of invasive aspergillosis: • Voriconazole as primary therapy in most patients • Liposomal amphotericin—alternative therapy in some patients • Options for salvage therapy; dependent on prior therapy, host factors, dosing considerations; potential agents: posaconazole, itraconazole, echinocandins, lipid amphotericin formulations. • Prophylaxis with posaconazole can be recommended in high risk patients (Walsh TJ, et al. Clin Infect Dis 2008;46:327-60) Role of topical antifungals: • The Mayo clinic has found that 6 months of irrigation with Amphotericin (250 micrograms/ml) showed 75 % improvement not only in the amount of mucosal thickening on the CT scan as well as endoscopic scores. • The Mayo clinic is now recommending a concentration of 100 micrograms/ml. • Although when given intravenously there are serious side effects with Amphotericin B, topically it causes minimal problems. • Some patients seem to respond to treatment with oral antifungals, including Sporanox, Diflucan, and possibly Nizoral.

Intranasal application of amphotericin B. Patients apply 20 mL of antifungal solution into each nostril using a bulb syringe. Arrow shows hand movement to accomplish successful application of the antifungal drug from medial (ethmoid) to lateral

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Advances in endoscopic sinus surgery Otolaryngologists have employed computer-aided surgery, or image-guided surgery, over the past two decades to enhance surgeon’s confidence, allow more thorough surgical dissections and possibly reduce the complication rate of endoscopic sinus surgery. Computer-aided surgery utilizes preoperative imaging to provide real-time localization of surgical instruments in the surgical field. Although computer-aided surgery originated in the neurosurgical realm, otolaryngologists soon appreciated that this technology could assist in identifying critical orbital or intracranial structures surrounding the paranasal sinuses, and potentially aid in decreasing complications. In this article, the history of imageguidance systems and their application to surgery of the paranasal sinuses and skull base will be reviewed. The components of computer-aided surgery systems and the currently available technologies for surgical instrument tracking are discussed, as well as the advantages and disadvantages of each of the tracking technologies. •

The term "stereotactic" was coined from Greek and Latin roots meaning "touch in space”.

•

A colorful term for this surgery is “neuro-navigation”.

•

Use images of the paranasal sinusis and the brain to guide the surgeon to a target within the brain by utilizing the stereotactic principle of co-registration of the patient with an imaging study.

Frameless stereotactic surgery • Based on the principle of the global positioning system. •

Relies on anatomical landmarks on the patient’s head and/or fiducial markers (temporary skin markers) which are taped to the scalp before the brain is imaged.

•

In the operating room the orientation of these markers is used to register the computer containing the brain images.

•

References this coordinate system with a parallel coordinate system of the three-dimensional image data of the patient that is displayed on the console of a computer-workstation so that the medical images become point-topoint maps of the corresponding actual locations.

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IMAGE GUIDED SURGERY Image-guided surgery (IGS), also known as surgical navigation, is a specific technology that visually correlates intraoperative anatomy with preoperative CT scans. Often IGS is considered to be analogous to the global position system (GPS), a technology that permits individuals to show their relative position on computer-generated map. For IGS, the preoperative CT scan serves as the map, and the intraoperative tracking system is similar to the satellites and devices that are used for GPS. During nasal surgery, an IGS system will show the position of an instrument tip relative to the preoperative CT scan images. Thus, the surgeon is better able to correlate intraoperative anatomy with the preoperative CT scans. Image-guided surgery may be helpful in situations • where complications might otherwise occur because of difficulty with recognizing the usual anatomy. • in case of frontal sinus disease, • in patients who need to be re-operated.

The CT scan images represent the coronal and reconstructed sagittal and axial views. The probe is at the level of the middle turbinate. As you can see, the cross-hairs indicate exactly where the probe is on each of the coronal, sagittal and axial views.

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The use of navigation for ENT procedures has improved patient outcomes. Its main uses are : • Revision sinus surgery • Distorted sinus anatomy of development, postoperative, or traumatic origin • Extensive sino-nasal polyposis • Pathology involving the frontal, posterior ethmoid and sphenoid sinuses. • Disease abutting the skull base, orbit, optic nerve or carotid artery • CSF rhinorrhea or conditions where there is a skull base defect • Benign and malignant sino-nasal neoplasms. The primary advantages to using our navigation solutions for FESS include: • Procedures are much less invasive than open surgical operations. • Precision is greater, resulting in lower risk to the patient. • Patient discomfort is minimal. • Procedure recovery time is shorter. ENT Procedures that can be done using the navigation system: • Transphenoidal procedures • Maxillary antrostomies • Ethmoidectomies • Sphenoidotomies/ sphenoid explorations • Turbinate resections • Frontal sinusotomies The ENT system is not only significantly more complex, it has to be more intuitive, as the cranial anatomy with all its sinuses, and nerves, and arteries and veins, is much more intricate. The system's navigation coordinates are provided by the Patient Registration Mask.

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BALLOON SINOPLASTY

• •

•

Sinus guide catheter is introduced into the nasal cavity under endoscopic visualization, sinus guide wire is introduced through the catheter and advanced into the target sinus. The sinus balloon catheter is introduced over the sinus guide wire and is positioned across the blocked ostium. The position of the balloon catheter is confirmed, and the balloon is gradually inflated to remodel the narrowed or blocked ostium. The balloon catheter is then deflated and removed, leaving the ostium open.

Author details: Dr. Sumit Mrig, Senior Resident, Department of ENT & Head and Neck surgery, Maulana Azad Medical College, Lok Nayak Hospital & Associated Hospitals.

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RADIOLOGY In ENT practice, CT offers great help not only in diagnosis but also in planning of sinus surgery, where half the exercise is already performed before actually starting the surgery by reconstructing 3D images of sinuses in the head of the operating surgeon. The radiologic characteristics of fungal sinusitis are very specific and aid in diagnosis and also guide towards the mode and the timing of appropriate treatment. Understanding the different types of fungal sinusitis and knowing their particular radiologic features allows the radiologist to play a crucial role in alerting the clinician to use appropriate diagnostic techniques for confirmation. Prompt diagnosis and initiation of appropriate therapy are essential to avoid a protracted or fatal outcome. Acute Invasive Fungal Sinusitis Acute invasive fungal sinusitis is seen predominantly in immuno-compromised patients or those with poorly controlled diabetes. Along with sinuses, nasal cavity is a frequent site of infection, with middle turbinate accounting for two-thirds of positive biopsy results. Angioinvasion and hematogenous dissemination are frequent with a mortality ranging from 50-80%.

Non-contrast CT image (a) in a patient with diabetic ketoacidosis with acute fungal sinusitis shows hypoattenuationg soft tissue within the nasal cavity & left ethmoid & frontal sinuses. Intracranial extension is clearly evident in this contrast enhanced T1W MRI image (b).

a

b

Hypoattenuating mucosal thickening or soft-tissue attenuation within the lumen of the involved paranasal sinus and nasal cavity is seen on NCCT. There is a predilection for unilateral involvement of the ethmoid and sphenoid sinuses. Rapid, aggressive bone destruction of the sinus walls is seen with intracranial and intraorbital extension of the inflammation. However, bone erosion may even be absent or very subtle and fungi tend to extend beyond the sinuses, along the blood vessels. Other complications include cavernous sinus thrombosis, carotid artery invasion, occlusion, or pseudoaneurysm with resulting cerebral infarct and hemorrhage. Whereas CT is better to assess for bone changes, MR imaging is superior in evaluating intracranial and intraorbital extension of the disease. Obliteration of the periantral fat is a subtle sign of extension beyond the maxillary sinus & should be specifically looked for. Leptomeningeal enhancement may be seen with intracranial invasion and with progressive infection, adjacent cerebritis, granulomas, and abscess formation may be seen. Intracranial granulomas appear hypointense on both T1- and T2-weighted images with minimal enhancement on contrast enhanced images. Chronic Invasive Fungal Sinusitis It usually occurs in immunocompetent individuals; however those with diabetes or a low level of immunosupression are susceptible. Patients usually have a history of chronic rhinosinusitis with a persistent & recurrent disease. Noncontrast CT reveals a hyperattenuating soft-tissue collection within one or more paranasal sinuses. Mottled lucencies or irregular bone destruction may be seen in the paranasal sinuses. There may also be sclerotic changes in the bony walls of the affected sinuses representing chronic sinus disease.

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There is decreased signal intensity on T1-weighted MR images and markedly decreased signal intensity on T2-weighted images. Infiltration of the periantral soft tissues about the maxillary sinus is an indicator of invasive disease. Invasion of adjacent structures such as the orbit, cavernous sinus, and anterior cranial fossa may lead to epidural abscess, parenchymal cerebritis or abscess, meningitis, cavernous sinus thrombosis, osteomyelitis, mycotic aneurysm, stroke, and hematogenous dissemination. Cranial nerve palsies occur with perineural spread. It may be mass like and differentiation from a malignancy may not be possible on imaging with destruction of the sinus walls and extension beyond the sinus.

a

b

c

Chronic invasive fungal sinusitis: (a) Clinical photograph of the patient showing perforation of the hard palate. (b) Coronal and T2W image showing left maxillary and ethmoid sinusitis . There is destruction of nasal turbinates, ethmoidal septae and hard palate forming an oro-nasal fistula (arrow). (c) Coronal post gadolinium showing a fungal granulomas with peripheral enhancing rim in left cavernous sinus & evidence of perineu ral spread with thickened enhancing mandibular division of trigeminal nerve coursing through the widened foramen ovale (black arrow)

Chronic Granulomatous Invasive Fungal Sinusitis This form primarily is primarily found in Africa & Southeast Asia. Individuals are generally immunocompetent & disease is characterised by formation of noncaseating granulomas in the tissues. Cross-sectional imaging findings are reported to be similar to those of chronic invasive fungal sinusitis. They may mimic an invasive mass lesion, with descriptive findings difficult to distinguish from those of a malignant neoplasm invading the paranasal sinuses, orbital soft tissues, infratemporal fossa, and skull base. Allergic Fungal Sinusitis Allergic fungal sinusitis is the most common type of fungal sinusitis & underlying cause is thought to be a hypersensitivity reaction to certain inhaled fungal organisms. It is characterised by the presence of “allergic mucin”, a yellow green inspissated mucus which contains eosinophils & Charcot-Leyden crystals. Allergic fungal sinusitis usually occurs in younger individuals that are immunocompetent, and often have a history of atopy. Involvement of multiple sinuses is a rule. Disease tends to be bilateral with a frequent nasal component. The majority of the sinuses show near-complete opacification and are expanded. Noncontrast CT demonstrates hyperattenuating allergic mucin within the lumen of the paranasal sinus. T1W images may reveal high signal intensity or mixed low, intermediate, and high signal intensity in these patients. There is characteristic low signal intensity or signal void on T2weighted images, which is attributed to a high concentration of various metals such as iron, magnesium, and manganese concentrated by the fungal organisms.

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a

b

Allergic fungal sinusitis: Axial unenhanced CT scans (a,b) show expansion of and increased attenuation in the anterior ethmoid, posterior ethmoid, sphenoid, and frontal sinuses bilaterally. There is characteristic hyperattenuating material within these sinuses (black arrows). Note also the smooth thinning of the posterior wall of the left frontal sinus (white arrows in b). On MRI (same patient) unenhanced T1weighted images (c) show characteristic high signal intensity within the left maxillary, left posterior ethmoid, and sphenoid sinuses (arrows in c). Corresponding T2-weighted MR images (d) show marked low signal intensity within the left maxillary, left posterior ethmoid, and sphenoid sinuses (arrows in d).

d

c

The T2 signal void is also attributed to a high protein and low free-water content of the allergic mucin. The inflamed mucosal lining is relatively hypointense on T1-weighted images and hyperintense on T2-weighted images and demonstrates enhancement after intravenous administration of gadolinium contrast material. There is no enhancement in the center or in majority of the sinus contents, which distinguishes this condition from neoplastic entities. Although the condition is not considered invasive, if left untreated, the involved sinuses expand and there is smooth bone erosion with subsequent intracranial or intraorbital extension and resulting cranial or orbital symptoms. Intracranial extension is usually limited by the dura to the extradural space. Fungus Ball Fungus ball appears as a mass within the lumen of a paranasal sinus and is usually limited to one sinus. The maxillary sinus is the most commonly involved sinus. A fungus ball typically appears hyperattenuating at noncontrast CT due to dense matted fungal hyphae & may demonstrate punctuate calcifications. The bony walls of the sinus may be sclerotic and thickened or expanded and thinned with focal areas of erosion from pressure necrosis. The fungus ball is hypointense on T1-weighted and T2-weighted images owing to the absence of free water. Calcifications and paramagnetic metals such as iron, magnesium, and manganese also generate areas of signal void on T2-weighted images.

Author Details: Dr. Vaibhav Jain, Consultant, Department of Radiology, Max Hospital Pitampura, New Delhi.

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JOURNAL SCAN de Shazo RD, Chapin K, Swain RE. Fungal sinusitis. New England Journal of Medicine. 1997; 337: 254-9.

Katzenstein AL, Sale SR, Greenberger PA. Allergic Aspergillus sinusitis: a newly recognized form of sinusitis. Journal of Allergy and Clinical Immunology. 1983; 72: 89-93.

Waxman JE, Spector JG, Sale SR, Katzenstein AL. Allergic Aspergillus sinusitis: concepts in diagnosis and treatment of a new clinical entity. Laryngoscope. 1987; 97: 261-6.

Bent 3rd JP, Kuhn FA. Diagnosis of allergic fungal sinusitis. Otolaryngology and Head and Neck Surgery. 1994; 111: 580-8.

Mabry RL. Allergic and infective rhinosinusitis:differential diagnosis and interrelationship. Otolaryngology and Head and Neck Surgery. 1994; 111: 335-9.

Marple BF. Allergic fungal rhinosinusitis: current theories and management strategies. Laryngoscope. 2001; 111: 1006-19.

Lorenz KJ, Frühwald S, Maier H. The use of the Brain LAB Kolibri navigation system in endoscopic paranasal sinus surgery under local anaesthesia-An analysis of 35 cases. Head and Neck Otology. 2006 Nov;54(11):851-60.

Ebbens FA, Georgalas C, Luiten S. the effect of Topical Amphotericin B on inflammatory markers in patients with chronic rhinosinusitis: A multicenter randomized controlled study. Laryngoscope. 2009; 119: 401-8.

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1. A. B. C. D. E.

The best confirmation of the diagnosis of AFRS requires: a positive fungal culture from the nose A positive fungal culture from the sinus. An elevated total serum IgE Positive surgical sinus histopathology. Positive fungal specific precipitins.

2. A. B. C. D. E.

The following are true regarding the treatment and follow-up of patients with AFRS except: directional trending of total serum IgE level can be prognostic Current research indicates oral antifungal drugs are effective as adjunctive treatment Amphotericin B is generally contraindicated oral corticosteroids have been found to decrease both symptoms and time to surgical recurrence Patients should be co-managed by both medical and surgical specialists.

3. A. B. C. D. E.

Which of the following statements regarding fungal sinusitis is/are correct: Bone destruction or extrasinus spread on imaging is essential for diagnosing invasive form. CT scan is the first modality of choice in such patients. Allergic type does not show bone destruction or intraorbital/intracranial spread. Intraorbital & intracranial extension is best depicted on thin slice axial & coronal CT. Loss of periantral fat pad is a sensitive marker for invasive variety.

4. Match the following radiological descriptions to the most probable type of fungal sinusitis: A. Mixed low & hyperattenuating material in left maxillary sinus on CT with tiny calcific specks. B. A diabetic with complaints of nasal obstruction & discharge for four months, with recent onset proptosis showing hyperattenuating soft tissue opacification of left ethmoid & maxillary sinuses, erosion & sclerosis of maxillary sinus walls & orbital cellulitis on CT. C. Bilateral frontal, anterior ethmoid & posterior ethmoid sinus involvement with hyperintense material on T1W and hypointense on T2W images, with mild expansion. D. T2 hyperintense mucosal thickening in maxillary, ethmoid and sphenoid sinuses with lack of visualization of flow void of left intracavernosal ICA.

For answers, click on the link below: http://enttrends.webs.com/

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