The incentive for this article1Does the use of computer-assisted surgery affect the margin status in resections of ameloblastoma?. was to investigate the efficacy of surgical cutting guides and their use in replicating pre-planned surgical margins of resection. This technology of computer-assisted surgery (CAS) is now ubiquitous in residency programs and practice. The utilization of CAS is often assumed to be safe, or at least equivalent to the prior method of determining margins intraoperatively using available imaging and gestalt. Although the literature is replete with studies displaying the accuracy of cutting guides in their ability to replicate orthognathic or reconstructive surgery, little evidence exists regarding margin status or surgical outcomes.Only recently have publications begun to provide some level of evidence to the safety and efficacy of CAS. One recent study was conducted by Roser, who investigated the surgical outcomes of CAS versus non-CAS surgery in squamous cell carcinoma.2Roser SM Ramachandra S Blair H et al.The accuracy of virtual surgical planning in free fibula mandibular reconstruction: comparison of planned and final results. We were surprised however, that this study focused on a soft tissue neoplasm, which is not readily visualized on computed tomography (CT).

We felt a more objective investigation to compare CAS and non-CAS surgery should initially be performed in a primary bony disease, which would be properly visualized with CT imaging. For this reason, we chose ameloblastoma, and focused our study on the mandible.

Ameloblastoma is one of the most common tumors of the head and neck.3Neville BW Damm DD Allen CM Bouquot JE. Oral and Maxillofacial Pathology. It is a tumor of odontogenic epithelium. Oral-maxillofacial surgeons have a uniquely close relationship with ameloblastoma, which is best described as a benign, aggressive neoplasm.4The ameloblastoma: primary, curative surgical management.Unicystic ameloblastoma has been considered a different entity from conventional ameloblastoma for 4 decades.5Unicystic ameloblastoma: a prognostically distinct entity. Unicystic ameloblastoma has 3 histologic subtypes: 1) luminal, 2) intraluminal, and 3) mural. Some argue enucleation and curettage can be performed for the less aggressive luminal and intraluminal variants, while the mural variant behaves similarly to conventional ameloblastoma and requires resection.The foundational article on the treatment of ameloblastoma was provided by Carlson and Marx in 2006.4The ameloblastoma: primary, curative surgical management. This study made apparent the failure of so-called conservative management – enucleation and curettage with or without peripheral ostectomy, liquid nitrogen or some form of Carnoy's solution – which has been shown repeatedly in the literature to have a recurrence rate approaching 60 to 80%.6Is there a role for enucleation in the management of ameloblastoma?. Carlson and Ruggiero noted the average extent of histologic disease was 4.5 mm beyond the radiographic margin, with a range of 2 to 8mm. It is because of this finding that Carlson and Marx treated patients with surgical resection using of 1.0 to 1.5 cm margins, including one anatomic barrier when this was not feasible. Carlson and Marx reported zero recurrences in their cohort.

At our institution, we treat ameloblastoma with this principle of primary curative surgical management. For the past decade, we have performed an increasing number of these resections using CAS, which has most recently allowed for accurate planning of immediate reconstruction. During these procedures, we often wondered after exposing the lesion and applying the cutting guides, would we have altered the location of the margin if performing this free-hand? Has any growth of the tumour since the time of imaging put our margins at risk? Is the use of CAS and cutting guides effective, and does it maintain the successful surgical outcomes that Carlson and Marx reported?

We believe our article provides initial evidence that the CAS and cutting guides performed in an equivalent, if not superior manner, when compared to non-CAS. As our results displayed, no close margins (≤2 mm) occurred with the CAS group, compared to 4 of 16 (25%) close margins occurring in the non-CAS group.

Long-term follow-up is still needed in our patient cohort. Although the majority of recurrent or persistent disease occurs within 5 years, some cases may occur up to 30 years later.7Recurrent ameloblastoma 30 years after surgical treatment.References

Does the use of computer-assisted surgery affect the margin status in resections of ameloblastoma?.

J Oral Maxillofac Surg. 79Roser SM Ramachandra S Blair H et al.

The accuracy of virtual surgical planning in free fibula mandibular reconstruction: comparison of planned and final results.

J Oral Maxillofac Surg. 68: 2824-2832Neville BW Damm DD Allen CM Bouquot JE.

Oral and Maxillofacial Pathology.

4th ed. Elsevier,

The ameloblastoma: primary, curative surgical management.

J Oral Maxillofac Surg. 64: 484-494

Unicystic ameloblastoma: a prognostically distinct entity.

Cancer. 40: 2278-2285

Is there a role for enucleation in the management of ameloblastoma?.

Int J Oral Maxillofac Surg. 38: 807-812

Recurrent ameloblastoma 30 years after surgical treatment.

J Oral Surg Am Dent Assoc 1965. 31: 368-370Article InfoPublication History

Accepted: March 26, 2021

Received: March 26, 2021

Identification

DOI: https://doi.org/10.1016/j.joms.2021.03.024

Copyright

© 2021 The American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

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