The Merit of Image Guidance in Endoscopic Frontal Sinus Surgery

Abstract

The introduction of image guidance navigation system in endoscopic sinus surgeries has been highly advocated in the recent past era. Ever since its introduction in the 1980s and 1990s in Germany it has been asserted that the image-guided navigation enhances surgical outcomes and diminished perioperative morbidities. The objective of this study is to reflect the experience of our institute with the image guidance navigation system in the frontal sinus endoscopic surgeries, specifically due to its constricted anatomy and proximity to vital structures. Retrospective chart review was performed for all image guided endoscopic frontal sinus procedures Performed at a tertiary referral center of King Fahad Specialist Hospital Dammam during the period from 2010 to 2019. A total of 450 endoscopic sinus and skull base procedures were performed using different image guidance systems. Out of the 450 cases, 231 cases were indicated for frontal sinus involvement. The fundamentals of anatomical knowledge are essential for the success of any surgery including image-guided surgeries. Utilization of image-guidance in endoscopic frontal surgeries assists in portraying the way to targeted frontal disease. It aids in localizing vital structures in distorted anatomy thus avoiding undesirable complications.

Introduction

The complexity of the frontal sinus anatomy marks it as a challenge for all otolaryngologists. Differing between individuals and even between sides endoscopic frontal sinusotomy remains a fearsome surgery. The grave complications that may occur with any frontal sinus surgery, add to the elevated rate of failure and recurrence heightens that fear [1]. The introduction of computer tomography guided surgeries alleviated the struggle of accessing the frontal sinus nevertheless the fear of injury of the adjacent vital structures remains an obstacle [12]. This study displays the application of computer tomography guided surgeries in versatile frontal sinus pathologies eliminating the need of external approaches.

Aim and Objectives

Reflection on the clinical value and applications of image-guided endoscopic frontal sinus surgeries at a tertiary hospital setting.

Material and Methods

A retrospective study of all image guided endoscopic frontal sinus procedures performed at a tertiary referral center of King Fahad Specialist Hospital-Dammam during the period from 2010 to 2019.

A preoperative CT scan of paranasal sinuses was obtained for all patients according to the standard navigation-protocol. The CT scan acquisition protocol requires contiguous 1 mm thickness axial slices.

Results

In the period from 2010 to 2019, a total of 450 endoscopic sinus and skull base procedures were performed using different image guidance systems in King Fahad Specialist Hospital Dammam. Out of the 450 cases, 231 cases were indicated for involvement of the frontal sinus and displayed here.

All cases were conducted under general anesthesia. Standard endoscopic sinus surgery equipment plus integrated instruments were utilized.

All surgeries were preformed using the aid of different optical and electromagnetic image guidance systems. An average time of 3 min was needed to install the image guidance system and to start the procedures with accepted accuracy of 1 mm.

The clinical diagnosis and indications of image guidance in our study are summarized in Table 1.

Table 1.

Clinical diagnosis and indications for image guidance

Recurrent sinusitis with and without polyposis	80
Revision sinusitis with distorded lost anatomical landmarks (Samter’s triad)	60
Fungal sinusitis (allergic fungal, chronic granulomatous and invasive)	40
Complicated sinusitis with intracranial and/or intraorbital extension	20
Benign sinonasal tumors (osteoma,inverted papilloma)	15
Frontal mucoceles and mucopyoceles	10
Frontal csf leaks and meningoencephaloceles	3
Endoscopic drainage of frontal lobe abscess	3
Total	231

Few Illustrative Clinical Cases

See Figs. 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10.

Fig. 1.

Recurrent sinusitis with dissection of remnant agger nasi cell to open the frontal recess

Fig. 2.

Revision recurrent sinusitis with polpys in samters sinustis with absent middle turbinate (lost landmarks)

Fig. 3.

Revision sinusitis, avoidance of injury to anterior ethmoid artery, orbit and skull base

Fig. 4.

Frontal sinus drainage with large lateral frontal cell dissection avoiding the external approach

Fig. 5.

Aggressive fungal sinusitis with intracranial extension

Fig. 6.

a Endoscopic drainage of complicated intracranial pyocele, b Endoscopic transfrontal drainage of frontal epidural abscess

Fig. 7.

a Endoscopic drilling of frontal peak and removal of neoosteogenesis in draf 3(median drainage) procedure for revision recurrent sinusitis b Endoscopic view of post op draf3 (median drainage procedure)

Fig. 8.

a CT scan with bilateral frontoorbital mucopyoceles displacements, b MRI with intracranial orbital, c Endoscopic drainage of pus (draf 2B), d 3 years post endoscopic drainage

Fig. 9.

Draf 3 (median drainage procedure) for recurrent frontal inverted papilloma

Fig. 10.

Frontal osteoma abutting the orbit and skull base

Discussion

The treatment definition of frontal sinus diseases incorporates relief of symptoms, elimination of disease, preservation of sinus mucosa with least morbidity. Ever since its description in the eighteenth century the frontal sinus surgery has been arduous [2, 3]. Ellis stated in 1954 “Perhaps it is as well that, like so many other interesting conditions, the disease of frontal sinusitis is becoming uncommon, since its treatment has always been difficult, often unsatisfactory and sometimes disastrous [2, 4].”

Frontal sinus surgery started with some obliteration procedure preformed by Runge in 1750 [1, 2]. Then in 1884 Alexander Ogston described external drainage as trephination of the frontal sinus [4]. After which several procedures were documented in history including Riedel-Schenke and killian frontal obliteration procedures that resulted in a lot of morbidities and high rate of failure [5–7].

That was followed by the era of combined approaches using intranasal and external approaches introduced in the early 1900s. Physicians such Schaeffer and Lothrop described such procedures and admitted to the dangers of these procedures with lack of visualization [8].

That led to the popularity of external approach again in the form of osteoplastic frontal sinus flap procedure in the 1960s. It had a low failure rate and a roadmap that was described by Becker in the form of ragiographic plate to sketch the frontal sinus anatomy [9].

The attempts of endonasal procedures were continuing with the aid of endoscope and microscope. Draf described his three different techniques: Draf type 1 frontal sinusotomy involves removal of obstructing disease inferior to the frontal ostium. Draf Type II frontal sinusotomy entails enlargement of frontal sinus outflow and contains type IIA that is removal of obstructing cells protruding into the frontal sinus between the middle turbinate and lamina papyrecea and Draf type IIB is resection of the frontal sinus floor between the lamina papyracea and the nasal septum. Draf Type III Frontal Sinusotomy (median drainage procedure) is removal of the frontal sinus floor on both sides and removal intrafrontal and nasal septum [10, 11].

Amongst the development of optical aided and computer aided sinus surgery the endoscopic sinus surgeries took a quantum leap. Image guided surgery is a term that portrays intraoperative navigation through the surgical field based on digital data obtained mainly from computed tomography, magnetic resonance imaging and others. The first image guided otolaryngology surgery was preformed in 1986 with a system developed at Aachen Technical University, Germany [12]. Image guided surgery provides the surgeon with three-dimensional reconstructed models of the patient’s preoperative images providing a navigator pinpointing the location of the surgeon in the field [13].

Image guided technology defiantly was utilized to help in mapping the operation of endoscopic sinus surgery facilitating sounder access to all sinuses avoiding penetration to vital structures (orbit and brain). In a 2010 survey of American Rhinologic Society 71% of the members thought there was a relative or absolute indication for the use of image guided technology in primary frontal sinus exploration and 96% in revision frontal sinus exploration [14]. Regardless a comprehensive basic knowledge of anatomy remains a mainstay for every surgeon.

Based on expert opinion in 2005 The American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) listed some indications for the use of image guidance in endoscopic sinus surgery including: [15]

• Revision sinus surgery.

• Distorted sinus anatomy of developmental, postoperative, or traumatic origin.

• Extensive sinonasal 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 sinonasal neoplasms.

The past references clarify the need of guidance in frontal endoscopic sinus surgeries as a sole indication.

Adding to the difficult access with endoscope to the frontal sinus the different pathologies of the sinus itself makes an endoscopic approach domed to failure. Several years ago pathologies such as the ones addressed in Table 1 were to be supremely managed with external or combined approaches.

Nowadays with the facilitation of image guided endoscopic navigation, pathologies such as cases of recurrent sinusitis, Samter’s triad, remnant agger nasi cell, bone erosion in invasive fungal sinsuistis and revision cases with distorted anatomical landmarks became conceivable. Figures 1,2,3,4,5 are illustration to such cases. These figures are demonstration of a difficult anatomy overcame with image guidance. It has been documented in literature that the use of navigation aided in the increase of performance of endoscopic surgery in the cases mentioned [16, 17].

For a case of acute frontal sinusitis complicated with epidural abscess, sole drainage with endoscopic approach was not preferable. In literature, Eviatar et al. drained an epidural abscess in a pediatric patient via endoscopic approach. That approach was orchestrated with the aid of image guided navigation [18]. Within the illustrated cases Fig. 6a,b represent cases of epidural and orbital abscess respectively that was also managed solely with image guided endoscopic endonasal approach.

An added benefit of guidance is the accuracy at which the Draf 3 can be completed resulting in excellent post operative long term results as seen in Fig. 7a, b.

In another example of a large bilateral frontoorbital mucoceles that is complicated with erosion of the orbit and skull base (Fig. 8a–d) was judged difficult with endoscopic approach alone, the mucocopyoceles were drained with image guided preservation of frontal outflow and sinus mucosa with no reoccurrence at 3 years follow up. A survey conducted in the United Kingdom revealed that 54 percent of the surgeons would still depend on external approach to treat such cases [19].

In Fig. 9 a case of recurrent inverted papilloma in the frontal sinus. The image guided with abundant accuracy, the location and attachments of the papilloma. St Paul’s Hospital, Vancouver, Canada documented their experience with frontal sinus recurrent inverted papilloma. They concluded, endoscopic approach with added benefit of image guidance resulted in excellent results with least morbidities [20].

Today frontal sinus osteoma is also treatable with endoscopic endonasal image guided approach. Although it is still debatable and certain criteria have been stated in literature depending on the location, size and attachment of the osteoma in the frontal sinus [21]. In the case demonstrated in (Fig. 10) a right frontal sinus osteoma attached to the skull base was successfully drilled out with no morbidities due to the aid of image guidance.

Conclusion

In the period of modern integrated instrumentation and image guidance endoscopic frontal sinus surgery is no longer obscure. The advances of reduce cost and decrease hospital stay elevate the benefits of image guided endoscopic frontal sinus surgeries. The use of image guidance can help identify critical structures (orbit and brain) in distorted anatomic landmarks, increasing the surgeon’s confidence and ability to perform a more complete dissection with minimal morbidities.

The Image-guided endoscopic frontal procedures allow the rhinologist to manage a wide spectrum of frontal sinus diseases like that illustrated in this study. Diseases of revision frontal sinusitis with distorted anatomy, extensive fungal sinusitis with intraorbital and intracranial involvement, complicated sinusitis with mucopyoceles abutting the orbit and skull base, median drainage procedure and different benign tumors in the frontal sinus all managed solely via endoscope approach with least morbidity.