(46) Revitalizing a Forgotten Technique: Use of the Reamer Irrigator Aspirator (RIA) to Obtain Non-vascularized Femur Grafts for Mandibular Reconstruction

Abstract: Intro
Oral and Maxillofacial Surgeons have a variety of materials and techniques available to reconstruct mandibular defects, of which, autogenous bone grafting is considered the gold standard due to its osteogenic properties (1). Non-vascularized grafts are typically obtained from the mandible, the anterior or posterior iliac crest, calvarium, tibia, and rib. When larger amounts of bone are required for reconstruction, extraoral locations are needed, but are often associated with significant morbidity to those areas. In orthopedic surgery, the reamer irrigator aspirator (RIA, Synthes) is commonly used to obtain intramedullary grafts laden with growth factors through a minimally invasive technique (1,2). Very few reports on the use of this technique exist in the OMS literature despite its promising results in orthopedic surgery.

Patients and Methods
Five subjects; four male and one female, aged 34- 73 years are included, all of which have been treated by the Oral and Maxillofacial Surgery department at the University of Cincinnati Medical Center from July of 2021 to present day. Four subjects had histopathology confirmed ameloblastomas, the other subject with an odontogenic myxoma. Four of five subjects received mandibular extractions and were allowed 1-2 months for mucosalization of sites prior to resection and reconstruction. Virtual surgical planning was completed with custom cutting guides and crib plates fabricated in each case. Each subject received an autogenous femur graft and Vivigen allograft at the time that ablative surgery was performed. For two cases, orthopedic surgery harvested the intramedullary femur graft via an antegrade (lateral hip) approach, and the other three via a retrograde (infrapatellar) approach. Both surgical sites were monitored for complications in the immediate post-operative period, and the mandibular sites were followed to subjectively determine the graft’s success in providing adequate bone for mandibular arch restoration.

Results and Outcomes Data
40-100cc of uncompressed medullary bone was obtained with the use of the RIA in each case, with the amount retrieved dependent on the size of the mandibular defect. All patients ambulated with assistance on post-operative day 0 or 1. More difficulty with ambulation was reported with the retrograde approach, as one patient required physical therapy for 3-4 weeks. Surgical complications from the mandibular surgery included intraoral dehiscence and post-operative infection, all of which resolved 1-5 months after their appearance. All five subjects were referred to our maxillofacial prosthodontist for restorative evaluation within one year of surgery. At this time, two of the five subjects have successfully completed restorative treatment, with one receiving a removable prosthesis and the other with implants and fixed prostheses. The remainder of subjects, whose surgeries were completed within the last 8 months, are still in process for restorative evaluation and treatment.

Conclusions
The RIA is a valuable tool for obtaining large amounts of autogenous, non-vascularized bone for mandibular reconstruction with minimal morbidity to extraoral surgical sites. Although the assistance of an orthopedic surgeon is needed to perform this technique, it is a viable alternative to the iliac crest approach, and should be considered more often.

Note: By the time of poster presentation, the remaining three subjects should have surgical site restoration in-process or completed

References:
1. El-Jawhari JJ, Ganguly P, Churchman S, Jones E, Giannoudis PV. The Biological Fitness of Bone Progenitor Cells in Reamer/Irrigator/Aspirator Waste. J Bone Joint Surg Am. 2019 Dec 4;101(23):2111-2119. doi: 10.2106/JBJS.19.00133. PMID: 31800424.
2. Cox G, Jones E, McGonagle D, Giannoudis PV. Reamer-irrigator-aspirator indications and clinical results: a systematic review. Int Orthop. 2011 Jul;35(7):951-6. doi: 10.1007/s00264-010-1189-z. Epub 2011 Jan 18. PMID: 21243358; PMCID: PMC3167404.

Panorex- completed restorative treatment

Retrograde surgical approach with RIA for harvesting femur graft

Guided placement of reaming nail prior to RIA use. Note- name that appears on image is my attending's- included as an author