The packing is first removed from the nose to visualize the decongested nose (Fig. 25.5). The punctum is dilated well to allow passage of a reinforced stainless steel #3–4 Bowman probe. This can be viewed endoscopically if an assistant is available who can hold the endoscope in place, but most often is done by feel, and after the probe is passed the endoscope is then introduced into the nares. Optionally, a retinal light pipe can be passed while viewing the nose with the endoscope (Figs. 25.6 and 25.7). This nicely demonstrates the location of the nasolacrimal sac in relation to the middle turbinate and can help the beginning surgeon to appreciate the appropriate orientation for the passage of the probe (Figs. 25.8 and 25.9). After the surgeon is familiar with the procedure, this step can often be omitted.

The reinforced Bowman probe is passed into the nose (Fig. 25.10). The probe should be oriented somewhat inferiorly and posteriorly and is then passed through the soft posterior portion of the lacrimal fossa. The probe should be viewed with the sinuscope. It should be found just inferior and beneath the attachment of the middle turbinate, or just slightly inferior and anterior to the middle turbinate. If the probe is inadvertently passed through the turbinate, it should be pulled back slightly. If the probe is in the wrong location or cannot be located, it should be removed and repassed. If the turbinate interferes, it can be gently pushed nasally with a freer elevator (Figs. 25.11 and 25.12). Resection of the turbinate can be performed in cases where it is severely encroaching on the area of the osteotomy (Fig. 25.13). Turbinate resection, however, is rarely necessary and can lead to additional scarring.

The nasal mucosa and thin posterior lacrimal fossa bone is filleted open with the stainless-steel-reinforced Bowman probe, by directing the probe posteriorly and superiorly around its pivot point (Figs. 25.14 and 25.15). In cases where this is difficult, a freer elevator can be used to guide the probe in the nose to perform this filleting process. A medium up-biting Blakesly forceps is then inserted closed into the osteotomy and spread, gently enlarging the osteotomy (Figs. 25.16, 25.17, and 25.18).

At this point, the osteotomy is ready for insertion of the deflated 9 mm endonasal balloon (Fig. 25.19). The placement is viewed endoscopically. The balloon is placed approximately 60 % into the osteotomy (Figs. 25.20 and 25.21). It is held in place as viewed with the endoscope as the assistant inflates the balloon to 8 atm of pressure. The balloon gradually enlarges the osteotomy, further fracturing the thin bone of the lacrimal fossa (Fig. 25.22). At this point, the balloon is pulled in a nasal direction into the nose while fully inflated (Figs. 25.23 and 25.24). This serves to pull the fractured lacrimal fossa bone and nasal mucosa toward the surgeon where they can be removed with endonasal instrumentation. This can be performed with a medium up-biting Blakesly forceps, or an up-biting cutter such as a Greenawalt forceps (Figs. 25.25 and 25.26). The osteotomy can be enlarged anteriorly with the use of up-biting or backbiting cutters (Fig. 25.27). A motorized suction cutter can also be used but is rarely necessary. We reported a success rate of 92 % utilizing this procedure in a series of 97 cases [6].