Clinical outcomes of patient-specific porous titanium endoprostheses in dogs with tumors of the mandible, radius, or tibia: 12 cases (2013–2016)

Abstract

OBJECTIVE To characterize the processes involved in and outcomes achieved with custom-designed patient-specific implants to provide functional replacement of skeletal structures in dogs with tumors of the mandible, radius, or tibia. DESIGN Prospective case series. ANIMALS 6 dogs with mandibular tumors, 5 with tumors of the distal aspect of the radius, and 1 with a tumor in the distal aspect of the tibia treated from June 2013 to September 2016 at 3 referral centers. PROCEDURES After tumor staging, implants were designed from patients' CT scans by means of various computer-aided design applications and printed by means of selective laser melting in titanium-6 aluminum-4 vanadium alloy. A cutting jig was created in thermoplastic to ensure each osteotomy was performed as planned. Following ostectomy, the implant was secured into the defect with screws of appropriate size and length. RESULTS Initial return to normal clinical function was good to excellent for 11 of the 12 dogs. However, major complications resulted in revision of the implant or amputation of the limb in 5 dogs, and at least 3 of these complications were considered a consequence of faulty implant design or manufacturing. Infection developed in 2 dogs and was successfully treated in 1 dog. The longest-surviving dog maintained good limb function for 2 years. CONCLUSIONS AND CLINICAL RELEVANCE This is the largest reported series of dogs managed with customized 3-D-printed titanium implants. The 3-D printing allowed complex and patient-specific 3-D geometries to be fabricated, enabling function-sparing treatment of bone cancer affecting multiple anatomic sites.

Limb‐sparing in dogs using patient‐specific, three‐dimensional‐printed endoprosthesis for distal radial osteosarcoma: A pilot study

“…It became apparent that this was an unrealistic expectation. In one veterinary study, a delay of up to 4 weeks was reported from the time of original examination for implant design to surgery . In a case report of a cat, the time between planning CT and surgery was 4 weeks but could have been shorter if it were not for customs and border issues .…”

“…After acquisition of the planning CT study, the surgeon evaluated the tumour with a radiologist and determined the proximal extent of the tumour in the radius. The site of the radial osteotomy was determined by adding 4.5 to 5.0 cm proximal to the most proximal extent of the tumour . The site was marked with a line on a sagittal image of the limb and saved as a JPEG file.…”

“…Limb‐sparing is most commonly performed for OSA located in the distal radius . Many techniques have been described for this anatomic site: cortical allograft, stainless steel endoprosthesis, distraction osteogenesis by bone transport, intraoperative extracorporeal radiotherapy, tumoral autograft pasteurization, microvascular ulnar autograft, ulnar rollover transposition, limb shortening, lateral manus translation, and patient‐specific, three‐dimensional (3D)‐printed endoprosthesis …”

“…Patient‐specific implants allow the implants to fit as perfectly as possible for each patient and therefore optimizing the loads transmitted through the limb. Patient‐specific implants are possible through computer‐aided design and 3D printing technology . This has the potential to reduce complications, particularly implant‐related complications .…”

“…The delay comes from the time required to design and print the individualized implant. In one case series reporting the use of 3D‐printed implants in dogs, 25% of dogs had their tumour increase in size during this waiting period, which required a more extensive surgery than originally planned . These personalized implants are designed, in part, based on the length of bone to be removed.…”