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S122: INTEGRATING MOLECULAR IMAGING INTO THE DESIGN OF CUSTOM CRANIO-ORBITAL IMPLANTS FOR SKULL BASE RECONSTRUCTION
Joshua M Tennyson, BS¹; Rishi Jain, BA¹; Rushmin Khazanchi, BA¹; Khizar R Nandoliya, BA¹; Zhishuo Wei, MD¹; Preeti J Thyparampil, MD²; Michael G DeCuypere, MD, PhD¹; Stephen T Magill, MD, PhD¹; ¹Department of Neurological Surgery, Northwestern University Feinberg School of Medicine; ²Department of Ophthalmology, Northwestern University Feinberg School of Medicine

Background: Spheno-orbital meningiomas (SOMs) cause hyperostosis and bone infiltration, leading to progressive visual symptoms and cosmetic deformities. Surgery remains the first line intervention. Emerging tools include DOTA-Tyr^3-octreotate (DOTATATE) positron emission tomography (PET), improving detection of the extent of transosseous spread, and custom patient-specific implants (PSIs), enabling rigid reconstruction after resection. However, data on combining DOTATATE PET and PSIs is limited, particularly for tailoring implant design to complex orbital contours.

Methods: Four patients (3/4 female; age 13-49) with SOMs who underwent cranio-orbital resection and rigid reconstruction with custom polyetheretherketone (PEEK) PSIs were retrospectively reviewed. In three cases, DOTATATE PET/CT delineated tumor extent and guided implant design, with fabrication involving contralateral mirroring, contour refinement, and a 4-mm offset tapered to 2-mm for smooth coverage. Reconstruction included vascularized pericranial flaps for soft tissue coverage and reinforcement. All procedures involved a multidisciplinary neurosurgery-oculoplastics team.

Results: Gross total resection was achieved in two cases. DOTATATE PET identified transosseous tumor margins and enabled precise PSI tailoring to the spheno-orbital surface, including the orbital roof and lateral wall. Proptosis and cosmesis were improved in all cases. Visual outcomes stabilized or improved in three cases. One patient developed diplopia and pseudomeningocele, both resolving conservatively. No implant-related complications were observed. DOTATATE-guided adjuvant radiotherapy is planned in two patients.

Conclusion: Combining DOTATATE PET with custom PSIs represents a novel strategy for SOM reconstruction, enabling improved aesthetics and high sensitivity and specificity for detecting SOMs during preoperative planning. Vascularized pericranial flaps provide reliable implant coverage, while multidisciplinary collaboration optimizes functional and cosmetic results. Further study in larger cohorts is needed to refine best practices for this combined approach.

Key words: Spheno-orbital meningiomas; DOTATATE PET; PSI; Cranioplasty

Table 1. Patient demographics, treatments, and outcomes.

Case	Age/Sex	Presentation	DOTATATE Radiotracer	Outcome
1	44yo F	Progressive right proptosis; occasional retro-orbital pressure	64-Cu	Subtotal resection; diplopia & pseudomeningocele resolved conservatively; planned adjuvant radiotherapy
2	40yo F	Intermittent headaches; 2–3mo blurred left vision; proptosis with cranial compression	68-Ga	Gross total resection
3	13yo M	NF2 mutation; 2yr worsening right proptosis/vision; bilateral optic nerve edema; RNFL thinning	None	Subtotal resection; poor vision persisted
4	49yo F	Left facial bulging and proptosis	68-Ga	Gross total resection; DOTATATE at 3mo to guide radiotherapy

Figure 1. Case 1. (a, b) Preop/postop MRI; (c) DOTATATE PET/CT; (d) custom PEEK implant.

Figure 2. Case 2. (a, b) Preop/postop MRI; (c) DOTATATE PET/CT; (d) 3D model.

Figure 3. Case 3. (a, b) Preop/postop axial MRI; (c, d) Preop/postop coronal MRI.

Figure 4. Case 4. (a, b) Preop/postop MRI; (c) DOTATATE PET/CT; (d) intraoperative implant placement.

 

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