5Frontal Sinus Mucociliary Flow & Clearance Frontal recess obstruction is the primary cause of chronic frontal sinusitis , not the sinus.During frontal recess dissection , if these cell walls are removed up to their attachment at the medial orbital wall , & the frontal recess and medial orbital wall mucosa is preserved intact , ciliary mucus clearance will continue uninterrupted .If this mucus membrane is damaged or removed , the sinus may not function properly after healing . Pseudostratified , ciliated columnar epithelium does not regenerate well after being stripped off of bone .
7Uncinate Process Wormald PJ 2008 . In most cases, the uncinate/medialwall of the agger nasi cell implants on the lamina papyracea.he classic description of the insertions of the uncinateIn 1, insertion into the lamina papyracea; 2, insertion into the skull base; 3, insertion into middle turbinateWormald PJ 2008
9AnatomyA common reason for ESS failure is inadequate removal of cells obstructing the outflow of the frontal sinus
10Single Agger Nasi Cell Without Frontal Cells the uncinate has a relationship only with the posterior half of the agger nasi cell and not with the anterior half,Wormald PJ 2008
11Single Agger Nasi Cell Without Frontal Cells line 1 representing a coronal cut through the anterior aspect of the agger nasi cell anterior to the middle turbinate. The diagonally striped, shaded area represents the area of thefrontal sinus above the frontal beak (black arrow). (From Wormald PJ.The agger nasi cell: the key to understanding the anatomy of the frontal recess.Wormald PJ 2008
12Single Agger Nasi Cell Without Frontal Cells line 2 representing a more posterior coronal cut through the posterior aspect of the agger nasi cell.This part of the uncinate forms the medial and posterior medial wall of the agger nasi cell and represents the relationship between the anterior agger nasi cell (shaded with dots) and the frontal beak and the floor of the frontal sinus (diagonally shaded area).Wormald PJ 2008
13Transition From Frontal Sinus To Frontal Recess The frontal sinus is relatively easy to identify; as it narrows toward the frontal ostia, it forms a square (Fig. 6-16). At this level. the posterior wall of the two frontal sinuses forms a straight line (Fig. 6-16). As the skull base turns poste- riorly,these squares elongate posteriorly but still maintain a roughly rectangular shape. This is the transition stage from frontal sinus to frontal recess (Fig. 6-16D). As the posterior ends of these boxes become pointed, so the scans reach the frontal recess (Fig. 6-16E). Figures 6-16A, B show the square formation of the frontal sinuses. The transition region is between Fig. 6-16D and 6-16E.The anterior wall bone becomes much thicker as the upper region of the frontal beak is reached (Fig. 6-16C). In Figs. 6-16D, E, the anterior wall is curved indicating that the nasion has been reached. In Fig. 6-16D, the nasion is fully developed and the frontal beak bone is thick.Wormald PJ 2008
14Frontal CellsType I is a single air cell above the agger nasi. Type II is a group of small air cells above the agger nasi, but below the orbital roof. Type III is a single air cell extending from the agger nasi into the frontal sinus. Finally, type IV is an isolated air cell within the frontal sinus not contiguous with the agger nasi. A Agger nasi cell, IS inner sinus septumType I is a single air cell above the agger nasi. Type II is a group of small air cells above the agger nasi, but below the orbital roof. Type III is a single air cell extending from the agger nasi into the frontal sinus. Finally, type IV is an isolated air cell within the frontal sinus not contiguous with the agger nasi. A Agger nasi cell, IS inner sinus septumKuhn FA 1994
15Frontal Cells Type I - Single cell above the agger nasi Type II - Two or more cells above the agger cellType III - Single cell extending from the agger cell into the frontal sinusType IV - Isolated cell within the frontal sinus
16Surgical IndicationsChronic sinusitis unresolved with maximal medical therapy;Polyps and allergic fungal sinusitisIntracranial complications of sinusitisMucoceles or mucopyocelesBenign neoplasms such as osteomas, inverting papillomas, or fibrous dysplasia.
21Endoscopic Frontal Sinusotomy Understand the patient’s frontal recess anatomyAscertain the anatomical reason for frontal recess/frontal sinus obstructionDetermine the best surgical approach to the problemThe combination of delicate endoscopic techniques, new frontal sinus instruments designed to allow the surgeon to work further up in the frontalsinus, and image-guided surgery, has extended the surgeon’s ability and reduced the need to use some of the other techniquesMany patients who might have required the combined above and below (endoscopic and trephine) approach 10 years ago now can be managed endoscopically
22Endoscopic Frontal Sinusotomy Principles Dissection should be performed from posterior to anterior and from medial to lateralPreserve all frontal recess mucus membraneThe frontal ostium can be stented or left alone!!!!/The posterior frontal recess table is commonly very thin and subject to penetration with subsequent cerebrospinal fluid (CSF) leak. The same pertains to the medial posterior frontal recess, bounded by the lateral cribriform plate lamella/ sinus mucus membrane does not regenerate over bare bone with normal cilia/ frontal sinus not only drains over the medial and posterior walls, but that it can be approached the same way from below (ie, posterior and medial). Consequently, once the ethmoid dissection is complete, the frontal recess cells can be removed with frontal sinus punches (Karl Storz) (Fig. 5) or fractured from posterior to anterior and from medial to lateral with frontal recess curettes/ depending on how widely open it is and how well the mucosa drapes over the edge of the frontal ostium. Soft flexible silastic stents rather than semirigid stents should be used/ semirigid stents induced circumferential scaring and osteoneogenesis at the frontal ostium in their dog frontal sinus experiments. Soft 0.01 inch thick silastic sheeting cut and rolled into a T shape makes an excellent frontal sinus stent.Kuhn FA 2006
30Surgical Outcomes Following the Endoscopic Modified Lothrop Procedure Conclusion: EMLP is a safe and effective surgical alternative to OPF for patients with recalcitrant frontalsinus disease. Major complications are rare. A large percentage of patients may require revision surgeryLaryngoscope, 117:765–769, 2007
31Frontal Sinus Trephination Finding the frontal recessMucocelesIsolated Type IV frontal cellsWith endoscopic techniques to assist with Draf II and III
33Endoscopic Frontal Sinoplasty The least invasive procedureIt can be used as a stand-alone procedure or with ethmoidectomyIt pushes the medial agger nasi cell wall laterally and the ethmoid bulla lamella posteriorlyK/ simple and straight-forward method of identifying the frontal sinus drainage pathway and identifying the air cell walls compromising it, which need to be removed./ When used as a stand-alone procedure, it provides a straight-forward means of cannulating the frontal sinus and dilating the drainage pathway without damaging the mucociliary clearance mechanism/ When performed with endoscopic ethmoidectomy, it is counterin- tuitive to leave any cell walls around the frontal ostium/ When viewed endoscopically several months postopera- tively, even though the remaining cell walls around the frontal ostium still seem as though they should have been removed. The frontal ostium looks healthy and is functiona/ under fluoro scopic control by endoscopically placing a 70 or 90 guiding cannula into the upper middle meatus and passing the guide wire through it up into the frontal sinus/Once the wire is in the sinus, a balloon catheter is passed over it into the frontal sinus, its position checked fluoroscopically, and the ballloon is inflated to dilate it fully/Kuhn FA 2006
35Frontal Recess & Frontal Beak This drawing illustrates the effect of a small. under- pneumatized agger nasi cell (AN). The frontal beak (FB) is large and the AP diameter of the frontal ostium (FO) small. The frontal recess (FR) is shaded and extends from the beak to the bulla lamella (BE).(B) This drawing illustrates the effect of a well-pneumatized agger nasi cell (AN) with a small frontal beak (FB) and large frontal ostium (FO). if the bulla lamella (BE) does not reach the skull base. a suprabullar recess (5BR) is formed. MT. middle turbinate.Wormald PJ 2008
36Osteoplastic Flap Vs. Draf III Narrow Nasal AirwaySmall Frontal SinusDeep NasionFloor of sinus < 1.5 cmHeavy thick nasofrontal beakProliferative osteitis, complicated chronic infectionFavor Draf III for mucoceles
38The frontal osteoplastic flap: does it still have a place in rhinological surgery The frontal osteoplastic flap still has a role in frontal sinus surgery.The Journal of Laryngology & Otology (2011), 125, 162–168.
39Osteoplastic FlapMay be modified tofit the patient
40Osteoplastic Flap Approach Osteoplastic and endoscopic (above and below approach)Frontal sinus obliteration/ Above and below is the procedure of choice for frontal sinus tumors, such as inverting papilloma, so that the sinus may be imaged postoperatively. It is also the procedure of choice for unobliteration, because it gives the best opportunity to completely remove whatever material was used to obliterate the sinus originally and to open the frontal recess. It also provides access to the farthest extent of the sinus to reconnect distant isolated pockets of mucus membrane to the frontal recess/Contraindications to frontal sinus obliteration are: missing posterior frontal sinus table bone, missing orbital roof bone, extensive supraorbital ethmoid cell pneumatization, frontal sinus tumor, and allergic fungal sinus/ FSO is now mostly reserved for only cases involving tumors in the frontal sinus region, extremely difficult revision cases, and cases of frontal sinus trauma./ One cannot be certain the mucus membrane is removed completely while preparing the frontal sinus for obliteration, even by drilling the bone/ One definitely cannot be certain of removing the mucus membrane from the dura or the periorbita, in each case, frontal sinus mucosa is adherent to soft tissue, either to the dura or to the periorbita/ As a rule, if there is any question about whether all of the frontal sinus mucus membrane can be removed, obliteration should not be performed./ The primary symptom of frontal obliteration failure is persistent, unremitting hard frontal pain. When all conservative methods have failed to account for or to control the pain, it is often necessary to re-explore the sinus./ When unobliterating a frontal sinus, the primary task is to reconnect the peripheral mucosalized areas to a functional frontal ostium. The second major task is recreating a functional connection to the nose or anterior ethmoid sinus/ There are clearly instances in which the Lothrop procedure, which is very straightforward when the frontal sinus is open, is the best solution to ensuring a patent ostium. In other instances, the endoscopic frontal sinusotomy is best/Wynn R, et al 2007
41Riedel's ProcedureOsteomyelitis of the anterior wall of the frontal sinusFailure of frontal sinus obliterationSome tumors of the frontal sinusRiedel's procedure can help eradicate frontal sinus disease and symptoms when drainage and obliteration have failed and there is persistent disease involving the anterior wall of the frontal sinus or the sinus itself. Aextradural Riedel's procedure preferable in dealing with chronic infection or locally invasive disease.. Riedel's procedure maintains a barrier in the form of the posterior wall of the frontal sinus and the intracranial contents. Postoperative disfigurement, the main criticism of this procedure, can be reduced to some extent by chamfering the margins of the frontal sinus along with the supraorbital rims (Figs to 53-21). Reconstruction of the anterior wall can be performed at a later date if necessary.Because the frontal sinus mucosa is completely removed, the chance of recurrent complications are few, and if recurrence happens, it can easily be recognized.
42Pearl #1 Carefully Examine the Anatomy in more than one CT plane Size of the frontal recessSize of the frontal sinusBony thickening or neo-osteogenesisIdentify the frontal sinus drainage pathwayNote the position of the anterior ethmoidal artery
43Pearl # 2 Identify the Anterior Ethmoidal Artery Superior extension of anterior wall of bullaNipple on the medial orbital wall1-4 mm’s below skull baseTypically posterior to supraorbital ethmoid cells
44Pearl #3: Plan the least invasive approach possible Ethmoidectomy with Middle Meatal Antrostomy without frontal recess surgeryFrontal recess surgeryEndoscopic frontal sinusotomyFrontal sinus trephinationUnilateral extend frontal sinus surgery (Draf II)Endoscopic Modified Lothrop (Draf III)Osteoplastic flap with or without obliteration
45Pearl #4 Positively Identify the Skull Base Posteriorly Skeletonize from posterior to anteriorOpen cells immediately posterior to the middle turbinateIdentify the sinus with a seeker
46Pearl #5 Positively identify the frontal sinus with a probe Need a relatively dry field45 degree telescopes are helpfulIdentify medial orbital wall and stay close to it dissecting superiorlyOpening to frontal sinus typically medialIdentify opening with a probe
47Pearl # 6 Preserve the Mucosa Consider leaving polyps if sinus is openRemove osteitic intersinus septae carefullyDo not traumatize unless sinus can be opened widelyStandard frontal sinusotomyDraf Type IIWorks well if you can:Preserve mucosaRemove bony partitionsCreate an ostium >4-5 mm
48Pearl #7 Keep the Sinus Open Postoperatively Remove fibrin and blood from frontal recess and frontal sinusRemove residual boneAntibiotics, topical steroids?Oral Steroids?
49Conclusion Very little evidence based medicine Do the least invasive procedures firstBe aware of various surgical optionsImage guidance a valuable toolFirst do no harm