The decision to perform surgery on a SPA depends on multiple factors and has been thoroughly described by Harris and coauthors in several published articles [7–9]. Not all abscesses require drainage, and the urgency of surgical intervention is determined using multiple criteria. Briefly, any abscess causing visual loss, optic nerve compromise, or intracranial complications needs to be drained emergently. Age is an important factor in this decision-making process [7–9]. Garcia and Harris discussed age as it relates to the need for surgical intervention [7]. Patients younger than 9 years of age with a small medial SPA not causing visual or optic nerve compromise can often be treated with intravenous antibiotics, and these abscesses may resolve without the need for surgery [7–11]. These subperiosteal collections are often due to a single aerobic organism, and, when surgery is performed, cultures are often negative [9]. Tables 8.1 and 8.2 summarize the indications for surgical drainage of SPA according to these studies.

In patients aged 9–14 years, there is a transition to more complex infections, and patients aged 15 years and older almost always require surgical drainage of the SPA. The urgency depends on the location, optic nerve status, and condition of the patient. These patients may also be watched expectantly over the first 24–48 h while being treated with intravenous antibiotics and undergoing frequent vision checks, but the surgeons must be prepared to intervene quickly if visual or systemic deterioration appears at any point during the course of the condition. These patients usually are found to have positive cultures at the time of drainage, with polymicrobial infections containing a combination of aerobic and anaerobic bacteria [9]. This difference in bacteriology is due to the effect of sinus maturation. Young children are less likely to develop anaerobic infections due to their larger ratio of ostia size to sinus size than that in older individuals. With increasing age, the sinus cavities enlarge greatly, while the ostia remain essentially the same size, therefore creating an environment more favorable for the growth of anaerobic bacteria [3, 5, 12].

Superior subperiosteal abscesses have a worse prognosis and are more likely to result in intracranial extension. They should be drained within the first 24 h. Inferior abscesses are unlikely to clear with antibiotic therapy alone and should also be treated within the first day of presentation [1, 3, 5, 7]. Todman and Enzer noted that the volume of the SPA measured on CT scan was a determining factor in identifying which patients needed surgery, both in the under and over 9-year-old age groups. Patients with a SPA volume of less than 1250 mm³ in their study did not require drainage. Additionally, they found that most patients with concurrent frontal sinusitis did not require surgical intervention [13].

Since most patients with orbital cellulitis and SPA have paranasal sinusitis, a decision must be made whether to drain the SPA only or to combine drainage of the SPA with sinus surgery. Dewan and coworkers studied patients with sinusitis and SPA and found that those with drainage of the SPA alone had statistically significant higher rate of reaccumulation of the SPA (5/9 patients), compared to those with combined SPA and sinus drainage (0/6 patients) [14]. Therefore, it is often beneficial to plan on both sinus and SPA drainage at the same time. One study revealed that patients with superior/medial abscesses treated with endoscopic drainage alone had a strong association with surgical failure and advocated combined internal and external drainage in those patients [15].

The surgical approach depends on the location of the abscess and the preference of the surgeon. Abscesses can be drained externally via a skin or conjunctival incision, or intranasally using an endoscopic approach.

External skin approach to a medial SPA. This commonly used approach is a modified Lynch incision, the traditional incision for performing an external ethmoidectomy. The incision is made on the side of the nose beginning at the medial aspect of the brow and extending inferiorly about 15 mm. (Fig. 8.2a) Dissection is carried down to the periosteum, and the periosteum is sharply opened with a #15 Bard-Parker blade. Care is taken to avoid the supraorbital and supratrochlear neurovascular bundles, the trochlea, and the medial canthal tendon. Subperiosteal dissection is carried out with a Freer elevator until the abscess cavity is entered. Cultures are taken of the abscess fluid, and the abscess cavity is suctioned to remove liquid pus and inflammatory exudate. A blunt Freer elevator can be used to gently open any loculations. The subperiosteal space is irrigated with an antibiotic solution, and a small Penrose drain is placed. The wound is closed in layers, and the drain is advanced over the next 2 days and then removed. The advantage of this technique is that it is an easy, direct approach to the SPA. The disadvantage is that it can leave an unsightly facial scar despite a meticulous closure technique. The combination of infectious material and the drain can affect the proper wound healing of the skin (Fig. 8.3).

External skin approach to a superior SPA . For a superior abscess, a sub-brow incision is made in the skin just inferior to the brow cilia laterally (Fig. 8.2b). Care is taken to avoid the supraorbital neurovascular bundle. The periosteum is identified at the orbital rim and incised either with a #15 Bard-Parker blade or the sharp side of a Freer elevator. The subperiosteal space is entered, and dissection is carried down posteriorly until the abscess cavity is identified. The pus is cultured and aspirated, and a small Penrose drain is placed and brought out through a separate stab incision (Fig. 8.4). The abscess cavity is irrigated with antibiotic solution, and the wound is closed in layers. The drain is advanced over 2 days and removed.

External skin and transconjunctival approaches to an inferior abscess . Either performing a transcutaneous approach or transconjunctival approach can drain an inferior abscess. For the transcutaneous route, a subciliary incision is performed with the eyelid pulled up using a 4–0 silk Frost suture. (Fig. 8.2c) Dissection is carried inferiorly in the plane between orbicularis muscle and orbital septum to the inferior orbital rim. The periosteum at the rim is incised with either a #15 Bard-Parker blade or a Freer elevator. Dissection is carried posteriorly to the abscess cavity, which is managed as described before.