**7. Historic development of operative methods**

The evolvement of surgical methods dealing with diseased or injured FS is described in several publications. The following summary is based on synopsis of two of them [1, 13]. In the preantibiotic era frontal sinusitis and its complications were fearsome, with high morbidity and mortality secondary to intracranial spread. The first reported procedure on FS for a mucopyocele was performed by *Wells* in 1870. Operations of limited extent involved punc‐ turing the anterior table, some with limited removal of the mucosa, packing of the sinus or creation of an external draining sinus tract.

In 1898 *Reidel* first described ablation of the anterior sinus wall. This radical, disfiguring operation involved removal of the frontal bone and supraorbital bar to the posterior table of the frontal sinus. *Killian* modified this approach in 1904 by preserving the supraorbital rims to improve the patient's appearance but still removing the anterior table and contents of FS and then collapsing the skin to the posterior table of FS. The Killian procedure produced less disfigurement but had significant rates of failure because of persistent disease at the naso‐ frontal ducts and incomplete removal of all FS mucosa. The next significant advance was the *Lynch* operation, described in 1921. The floor of FS and ethmoids were removed and the mucosa extirpated through a medial periorbital incision in an effort to re-establish drainage. Complete removal of the mucosa via this approach proved difficult. Disappointing results were also due to re-stenosis of NFD, either by scarring or by herniation of the orbital tissues into the created communication with the nasal cavity. Several modifications using stents and mucoperiosteal flaps were devised later in an attempt to maintain patency of this artificial conduit.

In 1955, *Bergara and Itoiz* described the osteoplastic approach, which consisted of first defining the extent of FS and then elevating the anterior sinus wall on an inferior pedicle of periosteum. This provided adequate surgical access to allow for visualization and complete removal of the sinus mucosa and obliteration of the remaining sinus with autologous free fat grafts. It also improved forehead cosmesis. The osteoplastic flap operation has been subsequently modified for use in trauma of the frontal sinus by elevating the pericranium with the scalp flap and exploring the frontal sinus by removal of the free bone fragments.

Later studies published by *Goodale* (1958) and *Montgomery* (1964) recognized the importance of NFD injury and popularized obliteration of FS with autologous fat. A variety of materials such as bone, muscle, fascia, and hydroxyapatite have been successfully used to obliterate the sinus cavity by later authors. In 1974, *Nadell and Kline* described a procedure to primarily reconstruct depressed frontal skull fractures involving the sinus and cribriform plates.

*Donald and Bernstein* (1982) described a cranialization, procedure in which the intracranial contents were isolated from the nose and the sinus was completely ablated. They validated this approach in a cat model by demonstrating respiratory mucosa regrowth and an infection rate of 44% with untreated posterior table defects.
