Virtual Planning For Surgical Reconstruction May Improve Outcomes for Patients With Head and Neck Cancer

Mandible reconstruction and maxilla reconstruction surgeries might be optimized with virtual surgical planning, according to an expert speaker at the 2022 Supportive Care in Cancer Annual Meeting.

Microvascular free tissue transfer with reconstruction has been in practice for 40 years now since its introduction in the early 80s, according to Eitan Prisman, MD, MA, FRCSS. 1 However, Prisman noted that accuracy and quality-of-life outcomes with reconstruction continue to represent an unmet need in head and neck cancer care.

Prisman, who is an associate professor of otolaryngology and head and neck surgery at the University of British Colombia, discussed the challenges of the standard practice during the 2022 Annual Supportive Care in Cancer conference. He also discussed how the application of virtual planning tools for surgical reconstruction may improve outcomes for patients with head and neck cancer.

“[During the procedure] we have a resected segment of the mandible or maxilla that we need to take free tissue transfer from other parts of the body with a microvascular suturing of the vessels. When we construct the mandible and maxilla, it’s really key to do it accurately so that we can restore not just cosmesis but function—swallowing, chewing, [and] breathing,” he said.

“[But] not all reconstructions are accurate. There’s [approximately] a 5% to 30% rate of nonunion of the bony reconstruction. There’s a 20% rate of plate extrusion. [And there are] a lot of things that we still do not completely comprehend in terms of patient’s quality of life after surgery. [However], a lot of software has been introduced to try to improve these reconstructions.”

Enter virtual surgical planning (VSP) into the equation, he said.

VSP is an important tool for oncologic osseous reconstruction of the mandible and midface, which is considered to be more precise than traditional methods.2 VSP begins with a CT scan, which allows surgeons to develop a 3-dimensional (3D) model of the mandible and radiologically define the segments of jaw that should be removed in order to achieve the preferred oncological ablation. When virtually preplanning, surgeons have as much time as they need, as well as the assistance of available mathematics and software to optimize a reconstruction plan.

After the resection is planned and defined in the virtual space, surgeons can print a 3D print cutting guide. “Once we commit to a virtual reconstruction, we can create a cutting guide for the fibula,” he said. “We print it on a 3D printer, sterilize it, bring it into the operating room, place it on the patient’s fibula and perform the cuts in the slots in order to achieve that optimal reconstruction.”

“Because virtual surgical planning allows surgeons to take time to curate a reconstruction guide to help them in the operating room, it allows for shorter surgery times,” Prisman said.

He shared a chart showing that the operation room time in minutes between patients whose surgeons used VSP for maxillary surgery (n = 10) and those who did not (n = 18), was 256 minutes vs 448 minutes, respectively. Further, the percentage of patients who needed tracheotomy was 20% vs 72%, respectively. The deviations between the plan and execution in surgery was a mean Δ mm of 7.5 vs 11.7.

“Historically, because the surgeries were longer there was more edema, we would [use a tracheostomy tube on] every one of our patients, [but] now our trach rate is approximately 20%,” Prisman said. “We rarely trach patients now because the surgeries are so much shorter. In addition, the length of [hospital] stay has decreased.”

Similarly, the literature suggests that VSP is associated with favorable outcomes in mandibular surgery as well.2 One study found that the mean distance between the actual mandibular osteotomy compared with the virtual mandibular osteotomy was 2.00 ± 1.12 mm.3 In a closer analysis of the fibular segments, with mean distance between the 2 was 1.30 ± 0.59 mm and the mean percentage overlap of actual plate to virtual plate was 58.73% ± 8.96%.

In a chart of mandible benefits that Prisman shared in his presentation, the deviations between the plan and execution in mandibular width, projection, and volumetric overlap were 2.32 ± 3.91, 2.39 ± 1.72, and 0.59 ± 0.51 mm respectively.1 There was also a significant reduction in operative time and length of stay, and no significant difference in complication rates.1,4

Further, the non-union rates were 7.3% and 18.8%, respectively.

“Anyone who does dental implants knows that we can’t implant the patient that doesn’t achieve union,” explained Prisman. “With virtual surgical plans, [it is] much more common to achieve union compared [with] freehand surgery, and that’s because we’re optimizing the variables that we can control.”

“Are we accurate [with VSP]?” he asked. “We pretty much are: our width and projection and volume overlap is within 2 mm.”

VSP allows surgery to feel more confident that everything will go according to plan, he concluded. It represents a good opportunity to improve accuracy.

One potential complication of VSP that Prisman noted is its relationship to increased cost. The planning, model, and cutting guides can result in an increased surgical procedure costs; however, some experts not that less time in surgery may results in decreased operating room use charges.2 The cost analysis is an ongoing debate and will most likely continue to be an area of further focus and examination.2

References

1. Prisman E. Virtual surgical planning in maxilla and mandible reconstruction. Presented at: 2022 Supportive Care in Cancer Annual Meeting; June 23-25, 2022; Toronto, Ontario.

2. Myers PL, Nelson JA, Rosen EB, Allen RJ Jr, Disa JJ, Matros E. Virtual surgical planning for oncologic mandibular and maxillary reconstruction. Plast Reconstr Surg Glob Open. 2021;9(9):e3672. doi:10.1097/GOX.0000000000003672

3. Rosen EB, Allen RJ Jr, Nelson J, Matros E. Inset guide for the osteocutaneous fibula flap with endosseous implants in oncologic jaw reconstruction. Plast Reconstr Surg Glob Open. 2019;7(10):e2475. Published 2019 Oct 10. doi:10.1097/GOX.0000000000002475

4. Wang E, Durham JS, Anderson DW, Prisman E. Clinical evaluation of an automated virtual surgical planning platform for mandibular reconstruction. Head Neck. 2020;42(12):3506-3514. doi:10.1002/hed.26404