Cases
SurgiCase CMF Plays a Key Role in Mandible Reconstruction after Tumor Resection
Case presented by D. Buchbinder, MD, DMD and M. Urken, MD, FACS, Beth Israel Medical Center, New York, USA
A patient of Dr. Buchbinder and Dr. Urken was diagnosed with a tumor of the jaw, called ameloblastoma. The tumor had grown so large that the patient suffered from severe facial asymmetry (see figure 1). An ameloblastoma is locally invasive and has a very high recurrence rate if not removed adequately. This means that a resection of the tumor has to be approached very carefully. In this case, the tumor’s size dictated the removal of a considerable portion of the jaw, which needed to be reconstructed.
Both surgeons wanted the best possible preparation for this complex surgery, so they decided to plan it virtually before they actually set foot in the operating room. They chose the obvious solution: SurgiCase CMF, Materialise’ revolutionary software for the virtual planning of cranio-maxillofacial surgeries. SurgiCase CMF helped them to plan this intervention down to the smallest detail.
Easily planning the tumor resection in 3D
CT scans were taken, but they failed to provide a strong foundation for diagnosis and treatment. Importing the scans into the SurgiCase CMF software offered some major advantages. SurgiCase CMF offered Dr. Buchbinder and Dr. Urken not only the axial view already provided by these scans, but also a coronal and a sagittal view. Next to this, the software produced an accurate 3D reconstruction of the patient’s skull. This allowed them to determine the tumor’s exact size and location. This way, SurgiCase CMF helped the surgeons to visualize and understand the precise dimensions of the ameloblastoma. Armed with that new information, they could plan their procedure virtually.
Dr. Buchbinder and Dr. Urken specified virtually the portion of the jaw that needed to be removed (see figure 2). They were now able to remove the tumor virtually in SurgiCase CMF. Without an accurate 3D reconstruction, a lot more time had to be spent during the surgery determining which areas they had to resect. Thus by using the software, the surgeons decreased not only the intra-operative decision making, but also the risk of running into unforeseen problems during surgery.
The virtual resection revealed the need for reconstructing the mandible. Considering the tumor’s size and the gap left after its resection, the surgeons wanted to eliminate any unpleasant surprises during the actual surgery. With SurgiCase CMF, they were able to mirror effortlessly the healthy mandible to the damaged side. This mirrored image proved to be very helpful for the later reconstruction. This way, the best aesthetic outcome could be assured.
Virtually reconstructing the mandible
To reconstruct the mandible, the surgeons decided to take a bone graft from the patient. Like most surgeons today, Dr. Buchbinder and Dr. Urken preferred to use a fibula flap. This flap provides the greatest bone length, is suitable for dental implants if necessary, and allows for incorporation of skin islands for soft tissue reconstruction.
To prepare for this phase of the surgery, the doctors obtained MRI scans of the patient’s lower limbs. Again, they used SurgiCase CMF to reconstruct a precise 3D model of the fibula bone (see figure 3).
They imported this fibula into the mandible planning project in SurgiCase CMF. Now they could start selecting, cutting and positioning the necessary fibula segments in such a way that they would fill the defect perfectly (see figure 3). SurgiCase CMF’s most important task at this juncture was to help the surgeons to determine the exact length and angulation of the different segments they needed to reconstruct the mandible. As a consequence, the surgeons were able to leave the distal portion of the fibula in place to maintain ankle stability. The proximal portion of the fibula was also left in its original place in order to avoid injury to the peroneal nerve.
Fig. 3: The 3D model of the fibula bone (in green) is imported in SurgiCase CMF. The different steps clearly show how easy it was for the surgeons to select, cut and position the segments.
Guiding the surgeons during surgery
After completing the virtual planning for both the resection of the tumor and the reconstruction of the mandible, it was time to convert the plan into action. Based on the SurgiCase CMF simulation, Materialise was able to design and manufacture a patient-specific cutting guide for the fibula resection. This guide, which fits to the bone in a single unique way, was used during surgery to mark the positions and angulations of the cuts that had to be made (see figures 4 & 5). Thanks to this unique guide, Dr. Buchbinder and Dr. Urken knew that their cuts were exactly as they planned in the software. All possible errors are thus eliminated.
Finally, in order to fix both fibula segments to the original mandible parts, the surgeons needed to use a fixation plate. They asked Materialise to manufacture a physical 3D model of the patient’s planned postoperative state. They could now prebend the fixation plate on this model with the confidence that it would be a perfect fit during surgery.
Fig. 5a: Guide used during surgery to locate the cuts - 5b: Result after usage of the guide - 5c: Comparison between the cut fibula and planned situation (via physical 3D model manufactured by Materialise)
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This case clearly shows that using SurgiCase CMF as a planning tool offered Dr. Buchbinder and Dr. Urken several advantages:
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