**8. Radical resection for a locally advanced basal cell carcinoma involving floor of the orbit and zygomatic bone**

This demonstrated case has long standing basal cell carcinoma of the left lower eyelid with extension into the orbit (**Figure 22**). The CT scan showed soft tissue mass with enhancement involving left lateral eyelid skin and subcutaneous tissue with extension to the pre-septal and post-septal left orbit. The lesion invades anterior portion of the floor of the orbit and zygomatic bone (**Figure 23**). The plan of surgical resection includes access through upper eyelid preservation with upper eyelid incision marked 2 mm beyond the eyelash margin, while on the lower lid the involved skin and soft tissue is generously resected en-bloc with the specimen (**Figure 24**). The upper lid dissection is done between anterior and posterior lamella of the eyelid, while the lower lid incision is full thickness at least 1 cm away from the visible tumor margin. The skin incision is deepened, leaving a generous amount of soft tissue on the lateral and inferior wall of the orbit to secure adequate margins around the tumor. The skin flap is elevated laterally, directly over the zygoma and the anterior bony wall of the maxilla. The upper lid dissection and periosteal elevation is similar to the steps described for above first case. The bone cuts to encompass the tumor are depicted on a skull (**Figures 25** and **26**). A power saw is used to make bone cuts for the proposed inferior orbital wall and zygoma resection. The inferior

**Figure 22.** *Basal cell carcinoma of the left lateral lower eyelid with orbital invasion.*

**Figure 23.**

*CT scan showing orbital invasion by periocular basal cell carcinoma. Erosion of the orbital rim and floor is noticed.*

rim of the orbit is divided medial to the infraorbital foramen to keep the lower lateral quadrant with the specimen with adequate bone margins (**Figure 25**). This bone cut extends through the floor of the orbit up to the optic foramen posteriorly. Bone cuts are made on the lateral wall of the orbit at fronto-zygomatic suture and zygomatico-temporal suture (**Figure 26**). This superior bone cut is extended through to the superior orbital fissure (**Figure 25**). Small osteotomes are used to

#### **Figure 24.**

*The plan of surgical resection through a upper lid sparing, while generous amount of skin and soft tissues are kept on lower lateral region.*

**Figure 25.** *The inferior rim of the orbit is divided medial to the infraorbital foramen.*

### **Figure 26.**

*Bone cuts are made on the lateral wall of the orbit at fronto-zygomatic suture (blue circle) and zygomaticotemporal suture (black circle).*

#### **Figure 27.**

*Anterior view of the total orbital exenteration and lateral orbital wall resection specimen.*

#### **Figure 28.**

*Lateral view of the total orbital exenteration and lateral wall removal specimen.*

complete the bone cuts and to mobilize the bony attachments of the surgical specimen. Once all bone cuts are completed, the surgical specimen remains attached only at the cone of the orbit posteriorly through the attachments of the extraocular muscles and the optic nerve. The orbital contents are retracted laterally and the posterior attachments of the extraocular muscles and the optic nerve are transacted with curved enucleation curved scissors to deliver the specimen (**Figures 27** and **28**). Rest of the steps are similar to as described for the above case for achieving hemostasis. Specimen and orbital defect is examined after hemostasis is achieved and reconstruction of the defect done.
