The complex and variable anatomy of the frontal sinus and recess makes the surgical treatment of chronic disease in this area both dangerous and challenging. Pneumatization of the frontal bone by numerous anterior ethmoid air cells during development may eff ectively block the already narrowed outfl ow tract of the frontal sinus. In addition, the area of the frontal recess is particularly poorly visualized during endoscopic sinus surgery owing to its anterior and cephalad position. These factors together increase the predilection for scarring and stenosis causing complete sinus obstruction that may be refractory to conventional endoscopic techniques [14, 19]. As well, the potential for injury to intimately associated structures such as the lamina papyracea, cribriform plate, and anterior ethmoidal artery is greater and can make surgery in this area a daunting task for the novice endoscopic surgeon. Because of the anatomic complexity of the region, Lothrop advocated an external approach for frontal sinus drainage and discouraged an intranasal approach. The Lothrop procedure consisted of bilateral external ethmoidectomy, removal of the frontal sinus fl oor with communication of both frontal sinuses through a large nasal septectomy. This external procedure required the removal of the lacrimal bone and a portion of the lamina papyracea, which caused medial collapse of the orbital contents and subsequent stenosis of the nasofrontal communication . The procedure did not gain much popularity and with the advent of the osteoplastic fl ap procedure in the 1960s, the Lothrop procedure was largely abandoned amongst surgeons. Despite being the "gold standard," the osteoplastic procedure with or without frontal sinus obliteration has a reported failure rate of approximately 10%, with a range of 6-25% [3, 15, 16]. It is also associated with postoperative morbidities such as frontal bossing, supraorbital neuralgia, donor site complications, and scarring . In the early 1990s, new advances in endoscopic sinus surgery technology allowed surgeons to revisit the management of recalcitrant frontal sinus disease through a completely intranasal approach. In 1995, Gross et al.  fi rst introduced the modifi cation of the Lothrop procedure as an alternative to the osteoplastic fl ap procedure. Their modifi cation involved a complete endoscopic intranasal removal of the frontal intersinus septum, frontal sinus fl oor, and anterior superior nasal septum, thus allowing a more precise surgical management of frontal sinus outfl ow obstruction using advanced drilling technology. Since the fi rst description of the procedure, several surgeons have reported success with the endoscopic modifi ed Lothrop procedure comparable to that with the osteoplastic fl ap procedure in the management of frontal sinus disease [2, 4, 6, 10, 12, 13, 18]. Because of its numerous advantages, such as improved cosmesis, decreased morbidity, and shorter hospitalization, this procedure is slowly becoming the procedure of choice over the osteoplastic fl ap procedure in the management of persistent frontal disease aft er failure of maximal medical management and conservative endoscopic sinus surgery. Indications have also expanded to include other conditions as listed below: 1. Indications (a) Failure of appropriate medical therapy and primary endoscopic frontal sinusotomy in the treatment of persistent chronic frontal sinusitis (b) Mucoceles of the frontal sinus (c) Inverted papilloma invading the frontal recess and sinus (d) Select osteomas (e) Trauma of the frontal sinus (f) Alternative to osteoplastic frontal sinus obliteration (g) Revision of a previous endoscopic modifi ed Lothrop procedure in a symptomatic patient demonstrating stenosis 2. Contraindications (a) Hypoplastic frontal sinus and frontal recess (b) Surgeon inexperience (c) Proper instrumentation unavailable (d) Sinus disease confi ned to supraorbital ethmoid air cells and not to the frontal sinus.
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