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Department of Surgery Division of Otolaryngology — Head & Neck Surgery UMDNJ — New Jersey Medical School Newark, NJ Modified Endoscopic Hemi Modified Endoscopic Hemi - - Lothrop Procedure for Supraorbital Lothrop Procedure for Supraorbital Frontal Sinus Access: A Cadaveric Study Frontal Sinus Access: A Cadaveric Study Mark E. Friedel, MD, MPH; Kim P. Murray, MD; Jean Anderson Eloy, MD Introduction The Modified Endoscopic Lothrop Procedure (MELP) or endoscopic Draf Type III, in its present form, was first described in the mid-1990s and has been gaining popularity among rhinologists over the years. Indications for this procedure include, among other things, the most severe forms of chronic frontal sinusitis where osteoplastic flap with obliteration is the only suitable alternative. 1 The MELP procedure, generally, involves removal of the inferior portion of the interfrontal septum, the superior-anterior nasal septum, and the frontal sinus floor extending to the lamina papyracea bilaterally, while preserving frontal sinus mucosa. 1 Despite ongoing enthusiasm for advanced endoscopic approaches to the frontal sinus, there is relatively scarce literature published describing the use of these techniques in addressing one-sided and laterally-based frontal sinus diseases. The lateral recess of the frontal sinus is one of the most difficult areas to address endoscopically. For difficult to access lateral disease, surgical intervention is often limited to external approaches or to advanced endoscopic techniques like the MELP. Given the ongoing acceptance of MELP as an efficacious and safe means of addressing difficult frontal sinus disease, we propose an alteration of this technique as an alternative to tackling supraorbital frontal sinus disease. 2-4 In this anatomic cadaver study, we demonstrate a new adaptation of the previously described MELP, which we have titled Modified Endoscopic Hemi-Lothrop Procedure (MEHLP), as an alternative to approaching supraorbital frontal sinus disease (Figure 1). Theoretical advantages of this procedure over MELP include decreased morbidity secondary to preservation of unaltered frontal drainage pathway on non- diseased sinus. References 1. Gross WE, Gross, CW, Becker D, Moore D, Phillips D. Modified transnasal endoscopic Lothrop Procedure as an alternative to frontal Sinus Obliteration. Otolaryngology--Head and Neck Surgery, 1995, pp. ;113;427-34. 2. Scott NA, Wormald P, Close D, Gallagher R, Anthony A, Maddern GJ. Endoscopic modified Lothrop procedure for the treatment of chronic frontal sinusitis: A systematic review. Otolaryngology--Head and Neck Surgery, 2003. v. 129, No. 4: 427-438. 3. Shirazi MA, Silver AL, Stankiewicz JA . Surgical Outcomes Following the Endoscopic Modified Lothrop Procedure.. 2007, The Laryngoscope, pp. ; 117; 765-69. 4. Anderson P, Sindwani R. Safety and Efficacy of Endoscopic Modified Lothrop Procedure: A Systematic Review and Meta-Analysis. The Laryngoscope, 2009, pp. ; 119; 1828-1833. 5. Draf W. Endonasal micro-endoscopic Frontal sinus suregery: the Fulda concept. Op Tech Otolaryngol Head Neck Surg, 1991, Vols. 2; 234-40. 6. Close LG, Lee NK, Leach JL, Manning SC. Resection of the intranasal frontal sinus floor. Annals of Otolaryngology, Rhinology, Laryngology, 1994, Vols. 103; 952-58. 7. Close LG. Endoscopic Lothrop procedure: when should it be considered? Current Opinion in Otolaryngology & Head and Neck Surgery, 2005, Vols. 13: 67-69. 8. Langton-Hewer CD, Wormald PJ. Endoscopic sinus surgery rescue of failed osteoplastic flap with fat obliteration. Current Opinion in Otolaryngology & Head and Neck Surgery, 2005, Vols. 13: 45-49. Conclusion • A review by Close et al 7 of the role of the endoscopic Lothrop procedure delineated the indications for use of this advanced procedure. Close proposed that MELP should be considered for the following indications including: failed prior endoscopic frontal sinus surgery, failed prior osteoplastic flap frontal sinus obliteration, resection of sinonasal neoplasms, as an approach to frontal sinus mucoceles and frontoethmoid fracture management, as well as for the removal of osteitic foci. 7 • We believe that laterally-based frontal sinus disease is a substantiated indication for advanced endoscopic procedures, and in particular, for a MEHLP in unilateral frontal disease. • The MEHLP, as demonstrated in this cadaver study, provided significant access to difficult to reach, lateral aspects of the frontal sinus in much the same way that a traditional Lothrop procedure has been described. The added advantage of angled endoscopy, especially the 70-degree endoscope, provided wide visual fields for safe access (Figure 2 and Figure 3D). In addtiion, by limiting the extent of surgical dissection to the diseased frontal sinus, we demonstrate the added advantage of preserving as much of the natural frontal drainage pathway as possible. • We believe MEHLP will decrease the potential post-operative morbidity by limiting dissection to only the affected frontal sinus. Additionally this may prove to potentially decrease operative time as well. • The MEHLP was demonstrated in our cadaver dissections to be a feasible approach and potential alternative to more traditional endoscopic procedures in addressing unilateral frontal sinus disease. This modification will be particularly useful to sinus surgeons in addressing difficult to access disease that may have otherwise required open approach or more extensive endoscopic resection. Abstract BACKGROUND: The Modified Endoscopic Lothrop procedure (MELP) has been shown in early studies to be a relatively safe and efficacious advanced approach to access the frontal sinus for eradication of recalcitrant frontal sinus disease. There has been limited data however that specifically addresses those patients with advanced, but unilaterally limited and supraorbitally-based, frontal sinus disease. In this study we propose a modification of the MELP technique, titled a modified Hemi- Lothrop procedure (MEHLP), which would limit the dissection of the MELP to removal of the frontal sinus floor of the unilaterally diseased frontal sinus, thereby sparing the mucosa and natural drainage pathways of the non-diseased contralateral frontal sinus. METHODS: An anatomic study via cadaveric dissection and photodocumentation was performed to demonstrate the MEHLP and to quantify the accessibility of this approach to far-laterally based frontal sinus disease. RESULTS: The MHLP was performed in three cadavers and shown to provide adequate access to the most distal supraorbital and laterally based aspects of the frontal sinus. Using multiple cadaveric donors, we demonstrated and described, through photodocumentation, the technique of MEHLP to access laterally based frontal sinus disease from the contralateral nasal cavity via a superior septectomy window. CONCLUSIONS: The MEHLP was demonstrated in our cadaver dissections to be a feasible approach and potential alternative to more traditional endoscopic procedures in addressing unilateral frontal sinus disease. We believe that this modification will be useful to endoscopic sinus surgeons in addressing difficult to access unilateral diseases that may otherwise have been addressed using open approaches or more extensive endoscopic resection than warranted by the disease process. This demonstration will help to define the accessibility of the lateral frontal sinus via a MEHLP and begin to provide estimates as to which patients may benefit from such an approach. Further study would be required to compare the potential morbidity and efficacy of this approach compared to more traditional endoscopic frontal sinus procedures. Contact Information: Mark Friedel, MD, MPH [email protected]: This study was supported by an unrestricted educational grant from the Dean’s Office of New Jersey Medical School Methods and Materials Cadaver Dissection We dissected a total of three cadaver heads provided by voluntary donation for medical education and research purposes through the Department of Anatomy at UMDNJ – New Jersey Medical School. All cadavers were fresh, supplied within one week of death, without prior dissection or manipulation based on availability. Dissection was performed with standard technique, at the UMDNJ – New Jersey Medical School. All dissections were performed using the same surgical instrumentation, which included Gyrus diego ® power dissector blades and burrs (Gyrus diego ® , Southborough, MA) and a standard endoscopic sinus instrumentation set. Standard 30 o and 70 o endoscopes were used interchangeably throughout the dissection procedures. A standard endoscopic sinus tower was used for video and photo-documentation. Description of Operative Technique: The Modified Endoscopic Hemi-Lothrop Procedure (MEHLP) begins, as described in the literature for the MELP, with identification of the frontal recess and frontal ostium, particularly of the diseased side. 5 With an endoscopic serrated soft tissue blade (Gyrus diego ® , Southborough, MA) mucosa is removed from the anterior face of the frontal recess bounded by the anterior-superior insertion of the middle turbinate. Dissection than proceeds initially in an anterior direction through the anterior insertion of the middle turbinate until the level of the nasal bones is reached. Medially, a portion of the nasal beak is removed until the nasal septum is encountered, thereby removing the anterior face of the frontal recess on one side. The perpendicular plate of the ethmoid is than removed up to the floor of the frontal sinus. The floor of the frontal sinus is than removed anteriorly to the nasal crest. As much bone as possible is removed anteriorly during this portion of the procedure to provide as large a frontonasal communication as allowed anatomically. An endoscopic superior-anterior septectomy is performed, as to provide adequate space to pass endoscope and instrumentation from the contralateral nasal cavity. It is at this point that a traditional MELP would proceed with drilling of the remnant of the nasal beak and frontal sinus floor toward the non-diseased side until the opposite lamina papyracea is reached. 5 However the MEHLP does not require this contralateral dissection. (Figure 1) Cadaver # Anatomic Dissection Results 1 Left MEHLP Antero-superior septectomy window provided access to the left frontal sinus via the contralateral nasal cavity. Lateral recess of frontal sinus could be accessed with standard sinus instrumentation. Excellent visualization of lateral sinus with 70-degree endoscope. 2 Left MEHLP Antero-superior septectomy window provided access to the left frontal sinus via the contralateral nasal cavity. Lateral recess of frontal sinus could be accessed with standard sinus instrumentation. Excellent visualization of lateral sinus with 70-degree endoscope. 3 Right MEHLP Antero-superior septectomy window provided access to the left frontal sinus via the contralateral nasal cavity. Lateral recess of frontal sinus could be accessed with standard sinus instrumentation. Excellent visualization of lateral sinus with 70-degree endoscope. Figure 1. Coronal Cut CT view through paranasal sinuses. Illustrations depict dissection technique for the Modified Endoscopic Hemi-Lothrop Procedure. Via the ipsilateral nasal cavity, a Draf II frontal sinusotomy is performed (Red arrow). Upon completion of ipsilateral Draf II, a anterior- superior septectomy is performed (white bracket) and the ipsilateral diseased frontal sinus is accessed via the contralateral nasal cavity (green arrow). Figure 2. Coronal Cut CT view through paranasal sinuses. Illustrations depict additional visual access to latera/supraorbital frontal sinus via the MEHLP approach. A) Schematic of visual field access via traditional ipsilateral frontal sinusotomy approach. B) Schematic of visual field access via Modified Endoscopic Hemi-Lothrop Procedure via contralateral nasal cavity. Figure 3. Endonasal view of cadaveric left frontal sinus via Modified Endoscopic Lothrop Procedure. A) Using 30-degree endoscope., visualization of left frontal sinus (small white arrow) via Draf II dissection in ipsilateral nasal cavity. Large white arrow indicates left nasal septum. Black arrow indicates lamina papraycea. B) Using 30-degree endoscope., visualization of left frontal sinus (white arrow) via Draf II dissection. Lamina paprycea denotes lateral extent of dissection (black arrow). C) Using 30-degree endoscope via contralateral nasal cavity, visualization through septectomy window (small black arrows) allows for adequate access of left frontal sinus (small white arrow). Large white arrow indicates right anterior nasal septum. D) Endonasal view of cadaveric left frontal sinus using 70-degree endoscope. Visualization of left frontal sinus (white arrow) demonstrates the access to the lateral depths of the frontal sinus with this technique.
