Plate Failure in Microvascular Osseous Recontructions

Statement of the Problem:  Osseous microvascular free flap reconstruction is a long accepted treatment following resection of the jaws.  Different vascularized osseous free flaps allow for adequate tissue and bone for reconstruction of defects from various causes and sizes[1].  Continued improvements in both surgical techniques and treatment planning, such as computer modeling and template design, improve the success of osseous microvascular flaps for facial reconstruction[2].  Although success rates of osseous free flaps are high, at our institution we have noted multiple instances of hardware failures occurring at different time periods from the original reconstruction.  Plate failures in osseous flaps require removal, adding morbidity in an already fragile patient population.  We seek to review the instances of hardware failure in microvascular osseous free flap reconstruction in order to identify causes and possible areas of improvement in order to prevent plate failure.         

Methods:  Retrospective chart review was performed on all patients treated with mandibular osseous microvascular free flap reconstructions in the Department of Oral and Maxillofacial Surgery at Bellevue and NYU Medical Center Hospitals from June 2006 to June 2012.  This included patients with osteonecrotic disease, osteomyelitis, benign and malignant neoplasms.  Patient diagnosis, treatment, age, sex, and follow-up time were collected.  Patients who had additional surgical procedures to remove reconstruction plates, for reasons other than complete microvascular flap failure in the immediate perioperative period, were considered plate failures. 

Results:  A total of 72 cases of patients receiving osseous free flaps were reviewed.  7 cases were found to have had plate failures requiring removal of the plate (9.7%). Preoperative diagnosis of the patients involved were 1 case of osteoradionecrosis, 2 case of bisphosphonate induced osteonecrosis, and 4 cases of squamous cell carcinoma (all had radiation).  The age of the patients experiencing plate failures ranged from 55 to 76 with an average age of 69 years.  Plates failed anywhere from 8 months to 41 months post-operatively.  Plates involved in the failures ranged in size from 2.0-2.8 mm plates.  6 patients had thick reconstruction plates. Each case of failure was reviewed in detail to determine possible causes.    All patients who had hardware failure had either radiotherapy or chemotherapeutic agents including bisphosphonates.  The most common presentation of hardware failure was a draining fistula.  All 7patients presented with fistula.  1 of 7 patients presented with pain.  There were no associated flap failures or ill toward events after removing hardware. One patient went on to develop ORN at the native mandible proximal to his reconstruction.

Conculsions:  With the advent of microvascular free flaps, surgeons have the ability to reconstruct large defects with healthy, vascularized tissue.  In some cases, although the vascularized osseous flap survives the plate used to fixate the new bone tissue eventually fails.  Although this may not cause a significant deviation from the ultimate reconstructive plan of the patient, it does pose a secondary procedure that patients must undergo.  Variables leading to failure seem to include radiation, diagnosis of ORN, BRONJ, and possibly thick plate choice.  Further research is warranted to look at each of these variables individually.

References:

1. Kim E, Evangelista M, Evans G. Use of free tissue transfers in head and neck reconstruction.  J Craniofac Surg. 2008 19(6):1577-1582
    
2. Hayden R, Mullin D,Patel A.  Reconstruction of the segmental mandibular defect: current state of the art.  Curr Opin Otolaryngol Head Neck Surg. 2012; 20(4): 231-236