Major complications of sinus surgery: a review of 1192 procedures

Evaluation of the Keros Classification of Olfactory Fossa by CT Scan in Qassim Region

Objective

Endoscopic sinus surgery (ESS) is now the most often utilized surgical procedure for treating chronic sinonasal disorders. Therefore, anatomical knowledge of its variations is required to avoid serious postoperative complications. Thus, careful preoperative examination for patients with a paranasal sinus CT scan is necessary. Our study aims to evaluate Keros types and their incidence by evaluating the olfactory fossa (OF) depth according to the Keros classification on paranasal sinus CT scans in the Qassim region.

Methods

A cross-sectional study was conducted between January 2018 and January 2021 on 148 patients with an average age of 32.59 ± 6.1 who had a non-enhanced paranasal sinus CT scan evaluated by a consultant radiologist using the PACS (picture archiving and communication system) software. Statistical analysis was performed using the statistical software package SPSS version 25 (IBM Corp., Armonk, NY). The chi-square test was used to analyze the relationship between findings and patient characteristics. Also, a p-value of < 0.05 was kept in mind to indicate statistical significance.

Results

The average depth of the right olfactory fossa (OF) was 5.1 mm with a standard deviation of 1.756 while it was 5.28 on the left side with a standard deviation of 1.66. According to the Keros classification, out of a total of 296 OF, type 1 was found in 84 (28.4%), type 2 in 188 (63.5%), and type 3 in 24 (8.1%). Consequently, the majority of cases were of type 2. Also, we found that type 2 was the most common on both sides in males, whereas, in females, type 2 was the most common on the left side and type 1 on the right side.

Conclusion

The study of the Keros classification is significantly important to evaluate the anatomy of the anterior skull base and give the surgeon knowledge about the depth of the olfactory fossa. Thus, a preoperative CT scan of the paranasal sinus is critical to ensure that the surgical approach is properly planned and possible surgical complications related to the anatomy of this area can be prevented. Our study showed that Keros type II is the most common, followed by type I and then type III.

Dental and Oral Manifestations of COVID-19 Related Mucormycosis: Diagnoses, Management Strategies and Outcomes

It has been nearly two years since the pandemic caused by the novel coronavirus disease (COVID-19) has affected the world. Several innovations and discoveries related to COVID-19 are surfacing every day and new problems associated with the COVID-19 virus are also coming to light. A similar situation is with the emergence of deep invasive fungal infections associated with severe acute respiratory syndrome 2 (SARS-CoV-2). Recent literature reported the cases of pulmonary and rhino-cerebral fungal infections appearing in patients previously infected by COVID-19. Histopathological analysis of these cases has shown that most of such infections are diagnosed as mucormycosis or aspergillosis. Rhino-orbital-cerebral mucormycosis usually affects the maxillary sinus with involvement of maxillary teeth, orbits, and ethmoidal sinuses. Diabetes mellitus is an independent risk factor for both COVID-19 as well as mucormycosis. At this point, there is scanty data on the subject and most of the published literature comprises of either case reports or case series with no long-term data available. The aim of this review paper is to present the characteristics of COVID-19 related mucormycosis and associated clinical features, outcome, diagnostic and management strategies. A prompt diagnosis and aggressive treatment planning can surely benefit these patients.

Laterality of Ethmoid Roof in a Korean Population

Background and Objectives: The olfactory fossa is an important anatomical structure to prevent surgical complications such as skull base injury and meningitis. The purpose of this study is to determine if there is a difference in lateral lamella length (LLL) between the left and right sides, a topic that has been studied rarely in Korea. Subjects and Method: We analyzed 592 left and right sides of 296 PNS CTs. We measured LLL as the distance between the fovea ethmoidalis and the horizontal cribriform plate in the olfactory fossa of the coronal surface where the crista galli was observed. Results: The average LLL on the left side was significantly longer than that on the right. Age and LLL showed a negative correlation. Multiple regression analysis revealed younger age and left side as independent variables for predicting increasing LLL. Conclusion: There was a significant difference between the two sides of LLL on sinus CT in Koreans. Before sinus surgery, the asymmetry of the ethmoid roof must be assessed, even by skilled doctors. If the height of the ethmoid roof is asymmetric, extra care is required during sinus surgery.

Anterior Skull Base Surgery via Endoscopic Endonasal Approach: Outcomes and Analysis

BACKGROUND

This study was retrospectively conducted to evaluate the postoperative surgical results of our patients with anterior skull base mass, defect, and/or cerebrospinal fluid rhinorrhea who underwent reconstruction via endoscopic endonasal approach and to share our experiences.

METHODS

Sociodemographic features of patients who had undergone endoscopic surgery in our clinic due to anterior skull base mass, defect, or rhinorrhea were evaluated in terms of etiological factors, surgical method, pathology, postoperative complications, need for revision surgery and comorbid disease.

RESULTS

A total of 131 patients were included; 76 were male and mean age was 36.2 years. Endoscopic endonasal surgery was performed for nasal mass (70.2%) in 92 cases, rhinorrhea (17.6%) in 23 cases, chronic sinusitis (7.6%) in 10 cases, and gunshot injury (4.6%) in 6 cases. After surgery, benign mass pathology was detected in 75 patients and malignant mass pathology was detected in 23 patients. Osteoma was the most common among benign formations, and squamous cell carcinoma was the most common among malignant formations. The most common cause of surgical revision was nasal masses (25 cases, 77.4%).

CONCLUSION

Endoscopic intracranial interventions and increased anterior skull base surgery are garnering increased interest of physicians as endoscopic approaches are gaining popularity in recent years. Successful results are achieved through appropriate diagnostic methods and endoscopic approaches. Success rates will be further increased due to developing technology and imaging methods, while the risk of complications and revision surgery will be further reduced.

Cribriform Plate, Crista Galli, Olfactory Fossa and Septal Deviation

OBJECTIVES

In the present study, we investigated the relationship between olfactory fossa, cribriform plate, crista galli and nasal Septal Deviation (SD). Keros classification of olfactory fossa was also performed.

METHODS

This study was performed retrospectively. Computerized Tomography (CT) images of 200 adult subjects were observed. Unilateral nasal Septal Deviation (SD) cases were included into the study. On coronal CT scans, SD side and location, SD angle, cribriform plate width, olfactory fossa depth (Keros classification) and width, area of the olfactory fossa, crista galli length, width and pneumatization were evaluated.

RESULTS

Anterior and anteroposterior deviations were detected mainly. In females, 64.0% and in males, 45.3% of the SDs were located anteriorly. In males, anteroposterior SDs (40.0%) were detected more than females. In anteroposterior SDs, SD angle was higher than anterior SDs. With higher SD angle, crista galli width and height decreased. Cribriform plate width, olfactory fossa height, width and area values of contralateral side were significantly higher than those of the ipsilateral side. For Keros classification, in male group, type 1 (53.3%) and in females, type 2 (57.6%) was detected at ipsilateral side. For contralateral side, type 2 Keros was detected in both genders. Complete crista galli pneumatization was observed in 4.0% and partial pneumatization was detected in 12.0%. In 84% of the patients, there is no Crista galli pneumatization. With the presence of pneumatized crista galli, contralateral Keros values decreased. Crista galli height and contralateral olfactory fossa width showed positive correlation. In older patients, cribriform plate width decreased.

CONCLUSION

In our study, there was no Keros type 3 olfactory fossa. In males' contralateral side of SD; and in females both ipsilateral and contralateral side of SD, Keros type 2 olfactory fossa were detected. Therefore, during sinus surgery, surgeons should work carefully not to made intracranial penetration.

Olfactory Fossa and New Angle Measurements: Lateral Lamella-Cribriform Plate Angle

OBJECTIVES

The authors investigated the olfactory fossa (OF) in patients with unilateral nasal septal deviation (NSD) and presented the lateral lamella-cribriform plate angle (LLCPA).

METHODS

Paranasal sinus computed tomography images of 300 adult subjects with unilateral NSD (111 males, 189 females) were evaluated retrospectively. Septal deviation angle (SDA), Keros Classification, OF depth and width, LLCPA; and orbital plate and cribriform plate (OPCP) distance were measured.

RESULTS

The OF depth values (ipsilateral, contralateral) were found as Keros III >Keros II >Keros I (Padjusted <0.0175). The OF width values (ipsilateral) were detected as Keros I >Keros II and Keros I >Keros III (Padjusted <0.0175). In patients with higher SDA values, ipsilateral OF depth values decreased (P <0.05). The LLCPA and OPCP values were higher in Keros I and lower in Keros III (P <0.05).

CONCLUSION

In patients with lower LLCPA and OPCP, endoscopic sinus surgery will be more dangerous for trauma to lateral lamella and intracranial penetration.

Ethnic Variation of Sinonasal Anatomy on CT Scan and Volumetric Analysis

To determine Ethnic differences in the frequency of the relatively common anatomical variants along with difference in anatomy of sinonasal region with surgical importance. A study was conducted to determine the frequency of anatomical variants, volumes of paranasal sinuses using computed tomography and to identify any difference between Group A consisting of people of Indian subcontinent and Group B consisting of people from north east Asian region. Volumetric analysis done using cumulative of area multiplied by slice thickness. The results were compared using Chi square test, p value < 0.05 was considered statistically significant. Among the common and uncommon anatomical variants (Agger nasi, pneumatized uncinate, concha bullosa etc.) there was no significant difference between the two groups. In both the groups Keros Type 1 was the most common type of ethmoid roof seen. On volumetric analysis sphenoid sinus volume was found to be higher in Indians without mongoloid features. Hence it's ideal that in this era of endoscopic sinus surgery we tailor make approaches to address individual anatomical variation.

Adult and Pediatric Lateral Lamella Cribriform Plate Height: In Need for a Comparative Study

Surgery for sinuses has evolved with the advancement of instruments and modification in techniques. Endoscopes have expanded the surgical roles for lesions in the nose and para-nasal sinuses with reduced rate of complications and cosmetic side effects. Nevertheless sinus surgery in pediatrics patients has its own challenges. Pre-operative imaging is of paramount important especially when embarking on skull base procedures. The differences between adult and pediatric anatomy need to be further studied.

Modeling Microdebrider-Mediated Ophthalmic Damage: A Word of Caution in Endoscopic Sinus Surgery

Background

The microdebrider has become nearly universal in the treatment of sinonasal pathology; however, recent case reports have demonstrated the potential for major ophthalmic complications. The goal of this study was twofold: 1) determine the anatomical proximity of ophthalmic structures to the paranasal sinuses, and 2) assess the timeframe at which ophthalmic injury may occur with the use of a microdebrider during FESS utilizing a cadaveric model.

Methodology/Principal

Computed tomography scans from 50 patients were accessed retrospectively. The distances between the lamina papyracea (LP) and orbital structures were determined at varying depths. Seven cadavers (14 sides) were studied using three microdebrider systems operated by otolaryngology residents. Following removal of a window of LP, the time from activation of the microdebrider on the periorbita until transection of the medial rectus (MR), optic nerve (ON), and to aspiration of the globe were measured.

Results

The mean distance between the LP and MR at the level of the anterior aspect of the anterior ethmoid and basal lamella were 3.59 ±1.2mm and 1.5 ±0.8mm, respectively. The mean distance between the LP and ON at the level of the basal lamella was 8.1 ±2.1mm. Mean transection times for the MR and ON were 13.4 ± 7.3 seconds and 37.3 ± 9.2 seconds, respectively, with minimum times of 4 seconds and 26 seconds.

Conclusions

The proximity of orbital structures to the paranasal sinuses and the rapidity of ophthalmic damage following violation of the periorbita reaffirms the need for cautious use of the microdebrider during FESS.

Outcome of Computer-Assisted Sinus Surgery: A 5-Year Study

Background

The aim of this work was to study the outcome and rate of complications in a cohort of patients who underwent computer-assisted surgery (CAS). A retrospective study was performed of all patients undergoing CAS at a tertiary care teaching hospital over a 5-year period.

Methods

All patients who underwent computer-assisted sinus surgery with at least 1 year of follow-up were included in the study. Charts were reviewed for indication of CAS, incidence of major complications, and need for revision surgery after CAS.

Results

A total of 120 patients underwent CAS in the 5-year period. Ten patients were lost to follow-up and were not included in the analysis. Indications for the use of CAS were revision surgery in 85 patients, sphenoid sinus disease in 12 patients, isolated frontal sinus disease in 4 patients, combined sphenoid and frontal disease in 2 patients, and cerebrospinal fluid leak (CSF) leak in 7 patients. The mean postoperative follow-up was 2.6 years. There were no major complications. Fifteen (16.5%) patients required revision surgery: 10 patients required revision endoscopic sinus surgery (1–5 revisions using CAS), 3 patients required an external open procedure, and 3 patients required revision CSF leak closure (one patient required both revision sinus surgery and an external procedure). There were no cases of major intra- or postoperative bleeding, central nervous system damage, CSF leak, or orbital trauma in this study.

Conclusion

CAS helps in avoiding trauma to the orbit and anterior skull base and has a low incidence of major complications. The need for revision surgery may occur in patients with frontal sinus disease, nasal polyposis, or recurrent CSF leak.

The Effect of Middle Turbinate Resection upon the Frontal Sinus

Diversity of opinion exists among otolaryngologists regarding the importance of preserving the middle turbinate during sinus surgery. The purpose of this study is to determine whether or not middle turbinate resection has a bearing upon postoperative disease within the frontal sinus. In this retrospective analysis of 110 consecutive patients with chronic or recurrent acute sinusitis, 69 (case group) had previous middle turbinectomy and 41 patients (control group) had intact middle turbinate after prior sinus surgery. In 42 patients, CT scans were scored and defined as having either mild-moderate or severe disease. Frontal sinusitis seen on CT scan was present in 75% (30 of 40) of case sides and 45% (9 of 20) of control sides, and this difference was significant (P < 0.05). The height of middle turbinate resection was measured, and there was no statistical difference in frontal sinusitis between patients with high and low resection. Therefore, this work does not support the concept that middle turbinate resection results in a lower incidence of frontal recess disease.

Extraocular Muscle Damage Associated with Endoscopic Sinus Surgery: An Ophthalmology Perspective

Background

Orbital complications associated with endoscopic sinus surgery are well documented. Damage to the medial rectus muscle results in complicated strabismus and disturbing diplopia. The aim of this study was to characterize the types of extraocular muscle injury and the number of muscles involved that may complicate endoscopic sinus surgery and correlate its occurrence to factors in the surgical procedure itself.

Methods

A retrospective chart review was performed of 14 patients with strabismus after endoscopic sinus surgery. Operative notes of the surgical procedure, pathology reports of the intraoperative specimens, postoperative pattern of strabismus, the extraocular muscle involved, and the type of muscle injury characterized by orbital imaging were reviewed in each patient.

Results

In our series, not only the medial rectus muscle but also the inferior rectus and the superior oblique muscles were damaged with multiple muscles being involved in one patient. Extraocular muscle injury varied from hematoma, entrapment of muscle in the fractured orbital wall, damage to the oculomotor nerve entry zone, muscle transection, and partial or complete muscle destruction with entrapment in scar tissue. Use of the microdebrider causes extensive irreparable muscle damage.

Conclusion

Extraocular muscle damage complicating endoscopic sinus surgery can produce therapeutically challenging complicated strabismus.

Complications in Sinus Surgery and New Classification Proposal

Complication overviews may lead to measures directed toward quality improvement and to better information for patients. When evaluating the rhinological literature from 1979 to 1999, a detailed comparison could not be made because of differences in reporting. With the advent of electronically stored medical data, events can be registered better than before. To be able to compile very diverse data from electronic dossiers into concise overviews for feedback, a simple general scale with broad categories is needed. These feedback overviews enable insight in the complication rates of different kinds of sinus surgery and monitoring of changing trends in sinus surgery. An example of a general classification based on severity is presented for use when electronically storing medical data. This scale varies from adverse events (grade A) to death (grade D). A consensus on categorization of complications is a prerequisite for a valid comparison with other clinics. To instigate a discussion about consensus, this classification is presented as an example. Our proposal is presented together with an overview of sinus surgery complications in recent literature for reference.

Sagittal and Coronal Dimensions of the Ethmoid Roof: A Radioanatomic Study

Background

Understanding the anatomy of the ethmoid roof is critical to safe surgical outcomes. Normative data regarding the height and slope of this region have been somewhat limited, derived primarily from cadaveric coronal computed tomography (CT) studies. With triplanar imaging programs, precise multidimensional measurements of the ethmoid roof are now possible. We present a radioanatomic study to characterize normative sagittal and coronal dimensions of the ethmoid roof.

Methods

Bilateral measurements were taken in 100 consecutive sinus CT scans using ThinClient 3D software. In the sagittal plane, the height of the ethmoid roof was measured in quadrants at five equidistant points between the frontal beak and sphenoid face, referencing the nasal floor. In the coronal plane, the ethmoid roof was measured at three points at the level of the anterior ethmoid artery and at two points at the junction of the posterior ethmoid and sphenoid sinuses.

Results

When examined sagittally, the right side showed significantly lower skull base heights in the anterior ethmoid compared with the left side (59.0 mm versus 59.8 mm, p = 0.017; 53.7 mm versus 54.5 mm, p = 0.0004). Coronal measurements of the anterior ethmoid roof showed similar significant differences. The anterior ethmoid roof had greater asymmetries of height compared with the posterior ethmoid roof, which was fairly constant.

Conclusion

This study provides numerical correlates to accepted concepts regarding the shape and slope of the ethmoid roof. Differences in height of the skull base between right and left sides, especially in the anterior ethmoid sinus, may be an important surgical consideration. The posterior ethmoid roof appears to be relatively constant and should serve as a reliable surgical landmark.

A Study of Clinical Significance of the Depth of Olfactory Fossa in Patients Undergoing Endoscopic Sinus Surgery

The endoscope has revolutionized the diagnosis and treatment of diseases of the nose and paranasal sinuses. Endoscopic sinus surgery (ESS), like all minimally invasive surgery, is designed to combine an excellent outcome with minimal patient discomfort. Successful outcome with minimal complications can only be achieved with good knowledge of the endoscopic anatomy, appropriate training in the procedure and the understanding of the anatomical variations. The intraoperative complications of ESS are bleeding and injury to surrounding structures commonly the orbital structures and fovea ethmoidalis. This is a hospital based prospective observational study with an objective to define the distribution of Keros classification of the depth of olfactory fossa and its asymmetrical distribution rates based on Keros type. Prospective study in a tertiary rural based hospital. 100 patients above the age of 10 years from October 2013 to March 2015 for a period of one year six months undergoing endoscopic sinus surgery in the Department of ENT, P.E.S. Institute of Medical Sciences and Research, Kuppam were chosen randomly. The data was collected from these patients who will met the inclusion criteria of the study and before undergoing endoscopic sinus surgery by subjecting them to CT scan of paranasal sinuses. It is observed that a total of 100 patients had been studied in which the mean age of the population is 36.65 + 13.36 years. Youngest patient was 12 years old and eldest patient was 70 years old. Among the patients 50(50%) were males and remaining 50(50%) were females with a female to male ratio is 1:1. In the present study, the depth of olfactory fossa ranged from 2.1 to 8.3 mm inclusive of both sides in 200 CT images with a mean height of 5.21 mm. Of the 200 sides measured, the distribution of Keros classification is as the following-Keros type I 39(19.5%), Keros type II 143(71.5%) and Keros type III 18(9%) sides. Based on these observations, type II is the most common Keros type prevalent followed by type 1 Keros type and the least prevalent is the type III Keros type in the studied population. In the present study, on considering sides separately, the right side olfactory fossa depth ranged from 2.1 to 8.3 mm with a mean height of 5.43 mm and the left side olfactory fossa depth ranged from 2.1 to 8.1 mm with a mean height of 4.98 mm. On the right side, of 100 sides measured, the distribution of Keros classification is as the following-Keros type I 19(19%), Keros type II 68(68%) and Keros type III 13(13%) sides. On the left side, of 100 sides measured, the distribution of Keros classification is as the following-Keros type I 25(25%), Keros type II 70(70%) and Keros type III 5(5%) sides. Based on these observations, type II is the most common Keros type prevalent followed by type 1 Keros type and the least prevalent is the type III Keros type in the studied population on both sides. In the present study, out of 100 patients 23 patients were having asymmetric olfactory fossa between right and left sides based on Keros type, where as remaining 77% had symmetric Keros type on right and left sides. Out of 23 patients, 16 patients were having lower or deep olfactory fossa on right side, where as remaining 7 patients were having lower or deep olfactory fossa on left side. Based on these observations, a lower or deep ethmoid roof occurred more frequently on the right side than on the left side. Wilcoxon matched pair signed rank test is applied to see the significant difference between depth of right and left olfactory fossae. Since P value is < 0.001 the depth of olfactory fossa is significantly different from each other. The present study presents a precise, quantitative analysis of the olfactory fossa and ethmoid roof position as well as individual asymmetry. This information may be useful during pre-operative evaluation of CT images, as well as intraoperatively. The surgeon's understanding of the anatomy of a patient's ethmoid roof and its possible variations is crucial for countering possible complication risks during endoscopic sinus surgery.

The Preoperative Sinus CT: Avoiding a "CLOSE" Call with Surgical Complications

Although functional endoscopic sinus surgery is an effective means of treating patients with recurrent and refractory sinusitis, the procedure is not without risk of serious surgical complications. Preoperative computed tomography (CT) affords radiologists the opportunity to prospectively identify anatomic variants that predispose patients to major surgical complications; however, these critical variants are not consistently evaluated or documented on preoperative imaging reports. The purpose of this review is to illustrate important anatomic variants and landmarks on the preoperative sinus CT with a focus on those that predispose patients to surgical complications. These critical variants and landmarks can be quickly recalled and incorporated into the preoperative imaging report through the use of the mnemonic "CLOSE": Cribriform plate, Lamina papyracea, Onodi cell, Sphenoid sinus pneumatization, and (anterior) Ethmoidal artery. This approach will greatly enhance the value of the preoperative imaging report for referring otolaryngologists and help reduce the risk of surgical complications. (©) RSNA, 2016 Online supplemental material is available for this article.

Refractory Chronic Rhinosinusitis with Nasal Polyposis

Chronic rhinosinusitis with nasal polyposis (CRSwNP) represents a subset of chronic sinusitis with various causes. Some forms of the disease are driven by allergy, often in association with asthma. Refractory CRSwNP can be associated with cystic fibrosis and other clinical syndromes. More recent literature is presented regarding roles of innate immunity and superantigens. Effective treatment of CRSwNP requires careful endoscopic sinus surgery followed by an individualized treatment plan that often includes oral and topical steroids. Recidivism of polyps is common, and patients require long-term follow-up.

An analysis of the anatomic variations of the paranasal sinuses and ethmoid roof using computed tomography

OBJECTIVE

To determine the Keros classification and asymmetrical distribution rates of the ethmoid roof and the frequency of anatomic variations of the paranasal sinuses.

MATERIALS AND METHODS

Paranasal sinus scans of 500 patients obtained using computed tomography were evaluated retrospectively. Measurements were performed using a coronal plan with right-left comparison and with distance measurement techniques. The depth of the lateral lamella was calculated by subtracting the depth of the cribriform plate from the depth of the medial ethmoid roof. The results were classified according to their Keros classification. Any asymmetries in the ethmoid roof depth and fovea ethmoidalis configuration were examined. The anatomic variations frequently encountered in paranasal sinuses (pneumatized middle concha, paradoxical middle concha, agger nasi cells, Haller cells, Onodi cells, etc.) were defined.

RESULTS

The mean height of the lateral lamella cribriform plate (LLCP) was 4.92±1.70 mm. The cases were classified as 13.4% Keros Type I, 76.1% Keros Type II, and 10.5% Keros Type III. There was asymmetry in the LLCP depths of 80% of the cases, and a configuration asymmetry in the fovea in 35% of the cases. In 32% of the cases with fovea configuration asymmetry, there was also asymmetry in the height of the right and left LLCP. The most frequent variations were nasal septum deviation (81.8%), agger nasi cells (63.8%), intralamellar air cells (45%), and concha bullosa (30%).

CONCLUSION

Using the Keros classification for LLCP height, higher rates of Keros Type I were found in other studies than in our study. The most frequent classification was Keros Type II. The paranasal sinus variations in each patient should be carefully evaluated. The data obtained from these evaluations can prevent probable complications by informing rhinologists performing endoscopic sinus surgery about preoperative and intraoperative processes.

Risks and medico-legal aspects of endoscopic sinus surgery: a review

The aim of this study was to perform a systematic literature review of risks and medico-legal aspects of endoscopic sinus surgery. The development of sophisticated technologies and instruments for endoscopic sinus surgery (ESS) has caused a dramatic increase in the number of otolaryngologists performing sinus surgery and the number of cases performed. This expansion was accompanied by an increase in malpractice lawsuits. Over the past 20 years, rhinology claims represented 70 % of the total indemnity compensation for otolaryngology claims and ESS was the surgical procedure most often involved. Only then will a careful analysis and assessment of the possible and potential risk factors of ESS, which may mislead the surgeon, allow a correct clinical risk management, with activities and procedures aimed at reducing the possibility of complications that may expose the physician to a malpractice suit.

Asymmetry of lateral lamella of the cribriform plate: a software-based analysis of coronal computed tomography and its clinical relevance in endoscopic sinus surgery

BACKGROUND

Endoscopic sinus surgery is a known approach for sinonasal pathologies. Due to close proximity of sinuses to orbits and brain, surgeon should be aware of sinonasal anatomy and associated variations. The roof of ethmoid (fovea ethmoidalis) separates the ethmoidal cells from the anterior cranial fossa. Medially the fovea attaches to the lateral lamella of the cribriform plate, which is the thinnest bone of the skull base. Hence, it is at a high risk of getting damaged during surgery.

OBJECTIVE

To ascertain the quantitative analysis of height of lateral lamella according to Keros classification in the computed tomographic (CT) images of patients presenting to our clinic.

METHODS

It was retrospective review of 77 CT scans using computerized software known as picture archiving and communication system. The height of lateral lamella was examined for both sides and then classified according to Keros classification. Asymmetry between two sides was also reported.

RESULTS

Keros type I was seen in 46 sides (29.8%), type II in 75 sides (48.7%) and type III was seen in 33 (21.4%) sides. Keros type I was seen in 38 sides in males and 8 sides in females. Type II was seen in 46 and 29 sides in males and females, respectively. Type III was seen in 18 sides in males and in 15 sides in females.

CONCLUSION

Understanding of the anatomy of ethmoid roof with its possible variation is crucial to give the surgeon optimal information about the possible risk that one can face during the surgery. Hence dreadful complications can be avoided.

A case report of orbital haemorrhage associated with endoscopic sinus surgery and reversible sight loss: a multidisciplinary approach to management

We report a case of intraoperative orbital haemorrhage as a complication of endoscopic sinus surgery performed under general anaesthesia. Initial unilateral complete visual loss occurred, but recovered due to accurate and early diagnosis combined with urgent surgical intervention. This patient's case is reported to illustrate the importance of early recognition of clinical signs and how a stepwise approach to management can result in a favourable visual outcome. Moreover, the mechanisms and pathophysiology of visual loss due to orbital haemorrhage following endoscopic sinus surgery are discussed.

Beyond the "central sinus": radiographic findings in patients undergoing revision functional endoscopic sinus surgery

BACKGROUND

Functional endoscopic sinus surgery (FESS) is widely used by otolaryngologists to treat chronic rhinosinusitis (CRS). The sinonasal anatomy and pathology found in patients with CRS varies widely, as does the FESS technique practiced by otolaryngologists. Variations in the completeness of cell group dissection, combined with the technical challenge of angled endoscopy, result in a wide variation of the post-FESS cavities harboring persistent disease. The purpose of this study was to identify previously incompletely dissected anatomic structures associated with mucosal thickening found in patients undergoing revision FESS for persistent or recurrent CRS.

METHODS

Retrospective review of axial, coronal, and sagittal computed tomography (CT) scans of patients undergoing revision FESS by 3 fellowship-trained rhinologists at a tertiary referral center.

RESULTS

The CT scans of 55 patients undergoing revision FESS were reviewed. The most frequent radiographic findings were residual anterior and posterior ethmoid cells or septations, found in 65% of sides and 75% of patients. In addition, residual anterior ethmoid agger nasi cells, unopened sphenoid, and residual uncinates were found in 52%, 51%, and 46% of sides, respectively. A large percentage of the patients demonstrated residual ethmoid cells present on the lamina papyracea and skull base, with a lower number found posterior to the middle turbinate basal lamella. A greater number of residual right-sided vs left-sided ethmoid cells was noted, with the difference being significant (p < 0.05) at the skull base.

CONCLUSION

Analysis of CT scans of patients undergoing revision FESS for persistent or recurrent CRS frequently reveals persistent anatomical structures or incompletely resected cells associated with persistent mucosal thickening. Meticulous, complete cell group dissection combined with use of angled endoscopy along with identification of possible predisposing structures may aid in the reduction of need for revision surgery.

Image-guided sinus surgery: practical and financial experiences from a UK centre 2001-2009

BACKGROUND

Image guidance surgery is an emerging technology that may allow more efficient treatment of sinus disease. This retrospective study examines National Health Service and military patients who underwent procedures using image guidance surgery during the period 2001-2009.

METHODS

Medical records were reviewed in terms of indications for surgery, incidence of major complications and need for revision following image guidance surgery. An attempt was also made to determine the cost-effectiveness of purchasing this navigational system.

RESULTS

A total of 132 patients underwent 147 procedures using image guidance surgery over the 8-year period. The indications for surgery ranged from severe nasal polyposis and chronic rhinosinusitis to malignant tumours in the paranasal sinus and skull base region. Average length of follow up was 17.6 months. Four patients had a major complication. Fourteen patients underwent revision surgery. The cost of providing an image guidance surgery service was estimated to be £110,000-120,000 during the study period. The economic model for the subgroup of nineteen military patients (with non-polypoid chronic rhinosinusitis) suggests that use of this technology will reduce overall costs by approximately £70,000 when compared with conventional sinus surgery.

CONCLUSION

This study provides some evidence that image-guided sinus surgery is cost effective, safe and may decrease surgical revision rates.

Radiological analysis of the ethmoid roof in the Malaysian population

OBJECTIVE

To ascertain the prevalence of the lateral lamella of the cribriform plate height according to Keros classification in the Malaysian population, and to find if there is any difference between the major ethnic groups in Malaysia (Malay, Chinese, Indian).

METHODS

Retrospective analysis of 150 CT scan studies of the paranasal sinuses.

RESULTS

The mean height of the lateral lamella of the cribriform plate (LLCP) in 300 sides was 2.64mm. Keros type I was seen in 240 sides (80%), while, Keros type II was seen in 60 sides (20%). There was no significant difference in the distribution of Keros classification among the major ethnic groups of Malaysia (Malay, Chinese, Indian). Keros type I was seen in 103 sides in males and 137 sides in females. Significant difference was observed in type II between the male and female (47 sides in males and 13 sides in female; p-value <0.001). When comparing the difference in the height of the LLCP in the same individual, asymmetry was observed in 139 patients. The LLCP height was higher on the left side in 71 patients and higher on the right in 68.

CONCLUSION

The understanding of the anatomy of the ethmoid roof with its possible variation is crucial to give the surgeon the optimal information about the possible risk that one can face during the surgery.

Height of right and left ethmoid roofs: aspects of laterality in 644 patients

Objective. The goal of the study was to determine the asymmetric distribution of the height of the ethmoid roof (fovea ethmoidalis). Method. We retrospectively reviewed 644 coronal sinus computer tomography (CT) scans. The height of the ethmoid roof was examined for possible lateral differences between the right and left sides. Results. In 221 CT scans (31%), there was an asymmetry between the height of the fovea ethmoidalis on the right and left side. Of these 221, 160 (72.4%) were lower on the right side, whereas 61 (27.6%) were lower on the left. The height of the ethmoid roof of the remaining 433 patients (66%) was symmetric. There were statistically significantly more asymmetric cases in men than in women (38% versus 29%). Conclusions. The present paper underlines the asymmetry, variability of the ethmoid roof, and the possible practical implications arising from that fact. The asymmetry of the roof of one side presents an additional point of consideration for careful preoperative and perioperative review of paranasal sinus CT scans in patients undergoing endonasal sinus surgery.

Traditional endonasal and microscopic sinus surgery complications versus endoscopic sinus surgery complications: a meta-analysis

The aim of this study was to compare the incidence of complications of endoscopic sinus surgery (ESS) to the incidence of complications of traditional and microscopic sinus surgery. A meta-analysis was carried out on 28 series of patients (a total of 13,405) who had undergone ESS, 8 series of patients (3,887 in total) who had undergone traditional endonasal sinus surgery and 7 series of patients (1,630 in total) who had undergone microscopic sinus surgery. The authors used the Bayesian inference package WinBUGS operating from within the statistical computer program R (version 2.7.1). Major complications had a higher incidence after traditional sinus surgery than ESS but this fact did not cause a significant statistical difference, whereas microscopic surgery had significantly more complications than ESS (p < 0.05). Carrying out our meta-analytic study, comparing major and minor complications of endonasal surgical approaches, was very difficult due to several methodological biases of data extraction and evaluation from studies concerning a broad timespan. Regarding major complications, we only found a significant statistical difference (p < 0.05) between the endoscopic (1%) and the microscopic methods (2.0%), but, if we had analyzed the data considering the natural learning curve of the latest ESS surgical approach, and if we had not considered the results produced in the first 10 years (1988-1998) concerning ESS in our meta-analysis, we would have found a statistically significant difference (p < 0.05) between the endoscopic (0.4%) and the traditional (1.1%) approach as well.

The prevention and management of complications in ethmoid sinus surgery

Prevention of complications during ethmoid sinus surgery begins with sound knowledge of the relevant anatomy, preoperative planning with use of radiologic imaging, and careful, thoughtful dissection intraoperatively. Despite these measures, however, complications may occur. This article highlights potential complications and treatment techniques to salvage good outcomes following endoscopic ethmoidectomy.

Multiplanar sinus CT: a systematic approach to imaging before functional endoscopic sinus surgery

OBJECTIVE

The purpose of this essay is to present a systematic approach to the use of coronal, axial, and sagittal images for CT evaluation of the sinuses before functional endoscopic sinus surgery (FESS).

CONCLUSION

We present a systematic approach to the use of coronal, axial, and sagittal images in CT evaluation before FESS. Each imaging plane is valuable for displaying anatomic variants, which can predispose a patient to recurrent disease and affect the surgical approach, and critical variants, which can make surgery hazardous.

Ophthalmic complications of endoscopic ethmoidectomy: a case report

Damage to ethmoid structures following removal of nasal polyps can cause severe complications. A patient aged 48 years with damage to right orbital structures sustained in the course of transnasal endoscopic surgery for ethmoid polyps was operated. After operation were complications.

Computer assistance for intraoperative navigation in ENT surgery

The intraoperative need for exact orientation during interventions in the paranasal sinuses and the augmented need for navigational aids in lateral skull base surgery have lead to the development of computer-aided tools during the last fifteen years. These tools, which provide the position of a tool or a pointer in the patient's preoperative radiologic imaging, have quickly gained a wide acceptance for revision surgeries and the surgical treatment of complex pathologies in Ear-, Nose- and Throat (ENT-) surgery. Currently, the use of such systems is spreading from academic centers to smaller hospitals and will become a standard tool in the near future. We review the present state of computer-aided surgery (CAS) systems, based on our experience as clinical and research centers with a long experience in the field, provide some technological background information and, based on selected cases, show the merits of this technology. The systems we have been working with cover a wide variety of intraoperative navigational systems in ENT surgery (Easy Guide, MedScan II, MKM, SNN, STN, SurgiGATE ORL, Treon, VectorVision, Viewing Wand, [without claiming completeness]), and virtually the whole area of ENT surgeries: macroscopic, (video-)endoscopic and microscopic procedures. The 3D tracking technologies involved cover mechanical, optical (active and passive), magnetic and robotic principles. The visualization tools used are computer monitors, video monitors, head-up-displays and the microscope's oculars, thus spanning the area from pointer-systems to real navigators and a surgical telepresence demonstrator, implementing the majority of available patient-to-image referencing strategies. Clinically, the systems can be operated with an acceptable accuracy of around 1 mm, whereas in laboratory settings and in cadaver studies application accuracy may be pushed to its limits: the physical resolution of the radiologic imaging used for navigation.

Invasive fungal sinusitis: An effective combined treatment in five haematological patients

Invasive fungal rhinosinusitis (IFR) is a life-threatening infection. Its onset is subtle and a late diagnosis leads to severe complications. Death may occur within a few weeks notwithstanding treatment. We describe a comprehensive pre- and post-operative approach to care for haematological patients with IFR. Five haematological patients with IFR were treated with systemic antifungal therapy and endoscopic surgical debridement of infected tissues, followed by amphotericin-B directly instilled in the sinuses by a new type of ethmoidal drainage. The IFR remitted in all cases; after 32 months of follow-up, three patients are still alive, and two have died of other causes. Two of the patients who experienced IFR progression to the brain at the IFR onset are still alive. The pharmacological and surgical approach with the post-operative local therapy by a new ethmoidal drainage system could support radical antifungal sinus treatment, thus improving the overall survival.

Preoperative Disease Severity at Sites of Subsequent Skull Base Defects after Endoscopic Sinus Surgery

Background

Skull base (SB) injury is a known complication of endoscopic sinus surgery (ESS). Risk factors for SB injury include poor visualization, low-lying SB, and SB asymmetry. Anecdotal evidence indicates that many SB defects occur in areas with minimal mucosal disease adjacent to the SB. We evaluated preoperative computed tomography (CT) scans to determine the degree of mucosal disease present at the site of subsequent SB defects caused by ESS.

Methods

Retrospective review of patients with SB injury as a result of ESS. Preoperative and postoperative CT films were reviewed for extent of overall sinus disease and disease at the site of the subsequent SB defect and presence of risk factors for SB injury.

Results

Preoperative and postoperative CT scans were obtained for 22 patients with 23 defects, who underwent 21 primary and 1 revision ESS. Fifteen (65%) patients had no disease, 2 (9%) patients had minimal disease, and 6 (26%) patients had complete opacification at the site of subsequent SB injury. SB defects occurred in the ethmoid roof (15 patients, 65%), lateral lamella (5 patients, 22%), cribriform plate (2 patients, 9%), and sphenoid sinus (1 patient, 4%). Risk factors for SB injury were only identified in 6 patients.

Conclusion

SB injuries resulting from ESS occurred in SB regions with minimal or no mucosal disease in over two-thirds of cases. Explanations for this may include thinner bone and mucosa in areas without chronic disease that is easier to injure and less resistance to dissection in minimally diseased areas. Caution should always be exercised in ESS, but especially in minimally diseased areas.

[Catheter-based balloon dilatation of the frontal, maxillary, and sphenoid ostia: a new procedure in sinus surgery]

BACKGROUND

Endoscopic sinus surgery is the procedure of choice for treating chronic rhinosinusitis. This paper describes a new minimally invasive method to restore ostium patency without removing tissue: the balloon sinuplasty technique.

PATIENTS AND METHODS

Two patients were treated with the new procedure. One patient had her maxillary and sphenoid ostia dilated; the other patient had both frontal ostia, both maxillary ostia, and the right sphenoid ostia dilated.

RESULTS

The balloon dilatations of the ostia were achieved successfully without impairing the mucosal circumference. There was no bleeding, and nasal packing was not necessary. The postoperative healing process showed no complications.

CONCLUSION

This paper discusses the advantages and disadvantages as well as the indications and contraindications of this method. The balloon sinuplasty technique is an easily performed surgery; for selected indications, it seems especially suited for opening blocked ostia.

[Microdebrider polypectomy and local corticosteroids]

OBJECTIVES

To subjectively evaluate the efficiency and tolerance of polypectomy using the microdebrider followed by local corticosteroids in nasal polyposis (NP) after medical therapy failure.

METHODS

Between 2000 and 2003, a polypectomy using the microdebrider was performed in 24 patients with NP. Efficiency was evaluated retrospectively by comparing pre- and postoperative functional and polyp scores. Efficiency was also evaluated regarding extension of NP on preoperative computed tomography (CT). Overall satisfaction was evaluated using a standardized phone questionnaire.

RESULTS

Mean follow-up was 23.6+/-12.5 months. The overall and individual functional scores and the anatomical score were very significantly improved after polypectomy using the microdebrider. Extension of NP on preoperative CT was not related to polypectomy efficiency. Among the patients surveyed, 87.5% were globally satisfied, 73% considered the operative conditions as satisfactory, and 83% qualified the postoperative period as simple.

CONCLUSION

Polypectomy using the microdebrider followed by local corticosteroids appears to be an efficient and well-tolerated treatment for improving functional symptomatology of patients with NP.

Endoscopic anterior ethmoidal artery ligation: a cadaver study

OBJECTIVE

The objective of this study was to investigate the radiologic and endoscopic anatomy of the anterior ethmoidal canal (AEC) and feasibility of endoscopic ligation of the anterior ethmoidal artery (AEA).

STUDY DESIGN

The authors conducted a prospective analysis of computed tomography (CT) of the paranasal sinuses and endoscopic cadaver dissection.

METHODS

Twenty-two cadaver heads had CT scans of the paranasal sinuses. The height of the lateral lamella of the cribriform plate was calculated and staged according to the Keros staging system. The presence of a bony mesentery, distance from AEC to the skull base, and dehiscence of the AEC were documented. Forty-four dissections were performed, the AECs identified, and AEA ligation attempted.

RESULTS

The mean height of the lateral lamella was 5.4 mm on the right and 4.7 mm on the left. In all cadaver heads with asymmetry, the right lateral lamella was longer (P<.005). A Keros type 1 pattern was seen in 23%, type 2 in 50%, and type 3 in 27%. Thirty-six percent of AECs were in a bony mesentery. AEC distance from the skull base was greater on the right (P<.009). A longer lateral lamella was correlated with the artery being in a mesentery. Sixteen percent of the AECs were dehiscent. Sixty-six percent of AEAs were unable to be clipped. Twenty percent were clipped effectively, all in a mesentery. In 14%, the AEA was not effectively clipped.

CONCLUSIONS

Endoscopic AEA ligation may be possible in some patients. The AEA should be in a mesentery for an effective clip to be placed and be associated with a dehiscence of the AEC. If the lateral lamella is classified as Keros grade 2 or 3, it is likely the AEC will be found in a mesentery.

Complications of Surgery for Nasal Polyposis and Chronic Rhinosinusitis: The Results of a National Audit in England and Wales

OBJECTIVE

The objective of this study was to determine the rate of complications of surgery for nasal polyposis and chronic rhinosinusitis as well as their risk factors. STUDY DESIGN, SETTING, PARTICIPANTS, AND OUTCOME MEASURES: The authors conducted a prospective study of 3,128 patients who underwent sinonasal surgery during 2000 and 2001 in 87 National Health Service hospitals in England and Wales. Patients completed a preoperative questionnaire that included the Sino-Nasal Outcome Test, a measure of sinonasal symptoms severity and health-related quality of life. Surgeons provided information about polyp extent, opacity of the sinuses on computed tomography (Lund-Mackay score), comorbidity (American Society of Anesthesiologists score), and the occurrence of perioperative complications.

RESULTS

Major complications (orbital or intracranial complications, bleeding requiring ligation or orbital decompression, or return to the operating room) occurred in 11 patients (0.4%). Minor complications (all other untoward events) occurred in 207 patients (6.6%). Most frequently reported minor complications were excessive perioperative hemorrhage bleeding (5.0%) as well as postoperative hemorrhage requiring treatment (0.8%). Multivariate analysis indicated that the complication rate was linked to the extent of disease measured in terms of symptom severity and health-related quality of life, the extent of polyposis, level of opacity of the sinuses on computed tomography, and the presence of comorbidity, but not surgical characteristics (extent of surgery, use of endoscope or microdebrider, grade of surgeon, and adjunctive turbinate surgery).

CONCLUSIONS

The risk of complications depended on patient characteristics rather than on the surgical technique used. Measures of the extent of disease and comorbidity may help in identifying patients at high risk of complications.

Current concepts in therapy of chronic rhinosinusitis and nasal polyposis

The exact pathophysiological mechanisms leading to chronic rhinosinusitis (CRS) still to a large extent remain obscure. However, recently there has been some progress in elucidating the etiology of nasal polyposis, especially regarding tissue eosinophilia as well as the role of aspirin intolerance and eicosanoid mediators. Endonasal sinus surgery has evolved to be the treatment of choice in CRS and nasal polyposis in all cases where conservative treatment has failed or resulted in only a partial or temporary relief. Today, state of the art in surgical technique includes the ability to combine microscopic and endoscopic procedures. Regardless of technical advances like powered instrumentation or computer-aided surgery, in a modern protocol, surgical therapy can offer only one option within a complex and individually tailored therapeutical concept. This review discusses current concepts and new developments in the diagnosis and treatment of CRS and nasal polyposis.

Computer-assisted surgical navigation in revision endoscopic sinus surgery

The anatomical variations of surgical landmarks associated with revision endoscopic sinus surgery (ESS) represent a significant challenge even to the most experienced surgeon. Multiple studies have demonstrated higher rates of both minor and major complications associated with revision cases. In the past decade, the availability of multiple computer-assisted surgical navigation systems has resulted in its widespread adoption as a tool in ESS.Computer-aided surgery (CAS) allows for triplanar anatomic localization, which may improve spatial orientation and help avoid trauma to vital structures, namely the orbit and anterior skull base.Theoretically, this would result in a lower rate of complications and a more complete surgical exploration. Future advances in CAS involve real-time computer-assisted surgical navigation using an operating room-based CT, C-arm, or MRI unit.

Cerebrospinal Fluid Rhinorrhea: Diagnosis and Management

Advances in imaging and endoscopic techniques have improved the ability to diagnose, localize, and treat in a less morbid fashion CSF leaks of the anterior skull base. An appreciation for the mechanism of leak and of the relationship between CSF production and absorption must be kept in mind when individualizing a repair. Increased CSF pressure caused by overproduction or underabsorption may result in persistence of a leak despite one's best efforts. Numerous advances in dural replacement grafts and tissue sealants have improved the ability to achieve watertight closure of the cranial vault. Microvascular techniques have allowed larger defects previously not reconstructable to be handled with relative ease by trained personnel. With expanded reconstructive techniques, the ability to handle larger disease processes of the skull base continues to expand.

Internal carotid artery injury during functional endoscopic sinus surgery and its management

Rupture of the internal carotid artery (ICA) during functional endoscopic sinus surgery (FESS) is a rare complication, which can potentially result in death. Only a few cases have been reported in the literature thus far. We present four cases with an ICA bleeding during sphenoidotomy. The treatment is discussed and an emergency plan to manage the heavy arterial bleeding is presented.

[Severe complications after endonasal nasal sinus surgery. An unresolved problem]

Functional endoscopic sinus surgery is one of the most common procedures in our field. Despite modern techniques, major and even fatal complications may occur. We describe 3 cases of unilateral blindness due to retrobulbar hematoma and one case of an internal carotid artery injury with fatal outcome.

[Management of cerebrospinal fluid fistulae: physiopathology, imaging and treatment]

Cerebrospinal fluid (CSF) fistulae can produce leakage through a defect in the bony skull and meninges into the contiguous air-filled cavities at the base of the skull. The major risk is central nervous system infection. When abundant clear rhinorrhea or otorrhea is present, the diagnosis is obvious and imaging is used to localize the fistula. Computed tomography (CT) with millimetric slices and magnetic resonance imaging (MRI) are the most effective diagnostic tools. CT cisternography, an invasive procedure, should only be used when the diagnosis remains uncertain following CT scan and MRI. When CSF leakage is sparse or intermittent, the diagnosis can be made by measuring beta-2 transferrine in the escaping fluid. CT scan followed by MRI are also useful for making the diagnosis and locating the fistula when exterior leakage is absent. CT scan alone is effective for assessing isolated otorrhea. If the diagnosis remains uncertain after all these studies have been used, the patient should be closely followed clinically and isotopic study or surgery should be considered.

Ophthalmic complications of endoscopic sinus surgery

The intimate anatomical relationship between the orbit and the paranasal sinuses places the orbit and its contents at risk of harm from primary pathologic processes of the sinuses. In the absence of ophthalmic signs or symptoms, ophthalmologists are not routinely involved in the management of patients with sinus disease. Occasionally, some patients may develop ophthalmic complaints after surgical intervention. The orbit, optic nerve, extraocular muscles, and lacrimal drainage system are susceptible to injury during endoscopic sinus surgery. The risk of injury is related to the skill of the sinus surgeon, history of previous surgery, extent and severity of disease, and anatomic variation. Furthermore, recent advances in endoscopic sinus surgery, in particular the use of powered cutting instruments, has resulted in a novel mechanism of injury to the ocular structures.

Medial rectus muscle injuries associated with functional endoscopic sinus surgery: characterization and management

OBJECTIVE

To characterize and evaluate treatment options for medial rectus muscle (MR) injury associated with functional endoscopic sinus surgery (FESS).

DESIGN

Retrospective interventional case series.

PARTICIPANTS

A total of 30 cases were gathered from 10 centers.

METHODS

Cases of orbital MR injury associated with FESS surgery were solicited from members of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) through an e-mail discussion group.

MAIN OUTCOME MEASURES

Variables assessed included patient demographics, computerized tomography and operative findings, extent of MR injury and entrapment, secondary orbital/ocular injuries, initial and final ocular alignment and ductions, and interventions.

RESULTS

A spectrum of MR injury ranging from simple contusion to complete MR transection, with and without entrapment, was observed. Four general patterns of presentation and corresponding injury were categorized.

CONCLUSIONS

Medial rectus muscle injury as a complication of FESS can vary markedly. Proper characterization and treatment are important, particularly with reference to the degree of direct MR injury (muscle tissue loss) and entrapment. Patients with severe MR disruption can benefit from intervention but continue to show persistent limitation of ocular motility and functional impairment. Prevention and early recognition and treatment of these injuries are emphasized.