Management of Atrophic Mandibular Fractures David R. Telles, DDS Diplomate of the American Board of Oral and Maxillofacial Surgery

Overview  Treating Atrophic mandibular fractures can be challenging due to patient population and surgical difficulty  Conflicting thoughts about treatment options – conservative vs. aggressive  Statistics  Historically  Treatment options

Statistics  by the year 2050 the population over the age of 65 will exceed 85 million people  by 2050 the percentage of our patients 65 years or older would be about double what it is today

Historically  Before the 1960s, management of the fractured atrophic mandible generally involved the use of closed treatment for reduction and stabilization or no treatment at all,  ‘‘skillful neglect.’’  The advent of Rigid internal fixation changed Tx  In some cases, the patient’s denture was attached with circummandibular wires and used to stabilize the fracture (monomandibular fixation)  If more stabilization was necessary  upper denture could be fixed to the maxilla via direct wiring, circumzygomatic  wiring, or pyriform aperture wiring  two dentures could be secured together using maxillomandibular fixation (MMF)

Techniques  Gunning Splints / CRMMF  Circum-mandibular wires  External pin fixation  ORIF

Gunning Splints  Technique created by Thomas Gunning in 1863  Impressions made of upper and lower arch  Mandibular casts is cut and realigned when there is considerable displacement  Separate units made for maxillary and mandibular arches  Opening made in the anterior region for nutritional purposes  Use is favorable when extreme mandibular atrophy is not present and the fracture is not comminuted  NOTE: fracture must lie in the denture bearing area

Gunning Splints

 Also have been used with open reduction non-rigid fixation techniques i.e. intraosseous wires  Peralveolar wires can be used in the maxilla if it is atrophic

Circummandiublar wires  Can be used with oblique fractures without gunning splints  Frequently leads to complications in healing  May lead to fracture instability

External Pin Fixation  Often indicated with severely comminuted fractures  Advantage = does not require subperiosteal dissection – therefore the blood supply is not compromised  Healing improved  2 limiting factors  Amount of bone available  Appearance of the patient  Anterior and posterior in area placed with a transverse bar spanning the fracture  Additional pin on either side allows for added support

Pearls  Closed techniques  Do not provide typically adequate resistance to the elevator muscles of mastication  Development of new technology and improved surgical techniques is to address the abnormal anatomy often present in the fractured atrophic edentulous mandible  Blood supply from the surrounding periosteum plays an important role in healing  Severe resorption may involve the mandibular canal  changing the blood supply pattern to the mandible  Sclerotic bone and poor circulation contribute to the high morbidity with atrophic mandibular fractures

Atrophic Mandibular classes  Created by Luhr et. Al.  Class 1 (16–20 mm)  Class 2 (11–15 mm)  Class 3 (%10 mm)  Cadwood et. Al  Further classified based on resorption patterns following tooth extraction  This type of resorption often results in knife ridge followed by vertical resorption until the basal bone of the mandible is encountered

Current Therapy  2 schools of thought  Closed technique – conservative Philosophy  Open Technique – aggressive Philosophy

Closed Techniques  As the pt loses dentition – there is less successive loss of osseous structure and a decreased blood supply  Reduction in vascularity can lead to diminished healing and increase risk for malunion/non-union  Bruce and Ellis et. al. reported that a decrease in height of the mandible increases the likelihood of complications related to fracture healing  Closed Technique is much less likely to result in complications compared to an open technique esp. in elderly pt.  With less bone Surface area – more precise open technique is required  Preferred esp in elderly population with multiple co- morbidities  Under GA the geriatic pt will experience morbidity 4x that of a younger pt

Closed Techniques

Open Techniques  Involves direct exposure of the fracture site and placement of internal fixation – preventing movement of Fx segments  Malocclusion not a concern – due to edentulism – hence Anatomic reduction is the goal  Approaches  Transoral  Mandibular body and symphysis fractures  Can be used to access most atrophic/edentulous mandibular Fxs  2 biggest RFs: lip malpositioning, mental nerve damage  Pro: no visible scar  Greater association with Infection and Non-union noted by Toma Et. Al.  Extraoral  Mandibular body Fxs, Ramus, Inferior border, angle  Concern = Facial Artery, Mental Nerve, Marginal Mandibular branch of CN VII

Open Techniques  3 common methods of Fixation  2.4-mm reconstruction plate  Strong enough to overcome the functional load + counteract masticatory forces  screws -- may cause another fracture upon placement  screws can fail by stripping the bone  leads to inflammation and bony necrosis  Large bicortical screws  injure the inferior alveolar nerve leading  lower lip dysesthesia  is the AO/ASIF – Treatment of choice  Allows for immediate function + resists hardware Fx  Titanium mesh  Locking miniplate

Open Techniques  Titanium Mesh Crib with Simultaneous ilac crest / anterior tibial / calvarial bone graft  Adv: use of autogenous bone graft – enchances bone the surgical site  DisAdv: morbility at the donor site: hip/lower leg gait disturbances, graft infection/resorption / non-union

Open Techniques  Locking miniplate  Theory – “ the smaller the better”  Least likely to result in periosteal stripping  Adv: ease of placement  Does not require as much bone density as compared to Reconstruction plates  Eryrich et. Al. noted – miniplates are subject to faiure due to inability to withstand the load placed on them by maxillomandibular forces  Lag Screw – no indicated due to decreased surface area of the bone

Open Techniques

Future developments  Madsen et. Al. in an article in JOMS – suggested the use of a 2.4 at the inferior border of the mandible via extraoral approach  Modified apron incision used to expose the inferior border of the mandible – provides good visualization for reduction and plating  Plate is secured by locking screws  3 adv  With us of EO – risk of wound Dehiscence and infection decreases  Biomechanics similar to a recon plate placed on the lateral border of the mandible  Pt may be able to continue to wear prosthesis– can further stabilize the fracture

Future Developments

Future developments  Louis et. Al 2004 – provides a new technique – with the use of resorbable mesh rather than titanium mesh – to rebuild the ridge in the site of atrophy using autogenous bone graft  Mesh is contoured to encompass the defect and secured with 1.5 mm tacks  Adv  Maintains the shape/location of the graft during the consolidation phase  Does not require a 2 nd surgery to remove it  Can be shaped into different configurations to follow the contour of the mandible  Also involves stabilization of the Fx with a recon plate

Future Developments  Use of alloplastic material in place of autogenous grafts increasingly favored – avoids morbidity of donor site  No 2 nd surgical site  Alloplastic materials include: Hydroxyapatite, Tricalcium Phosphate, Glass Ceramics, Glass Carbonate  Materials vary and have limitations – permanent vs. biodegradable, naturally occuring vs. synthetic, porosity, mechanical compatibility  Injectable Calcium Phosphate – shown to be biocompatible and have valid application in atrophic mandibular reconstruction  can be used for ridge augmentation procedures  Covalent linking of cpds e.g BMP2 with meshes/plates – represents a novel growing method of delivering concentrated growth factors

Summary  Many surgeons find repair of Fx atrophic edentulous mandible difficult  Conservative vs. Aggressive approaches to Tx  At the population ages – the OMFS surgeon is expected to Tx more of these types of fractures  Thorough understanding of all Tx options available necessary – as there are adv and disadv to each

References  Madsen, M. Haug, R, et. al. Management of Atrophic Mandible Fractures. Oral Maxillofacial Surg Clin N Am 21 (2009) 175–183.  Zide MF, Ducic Y. Fibula microvascular free tissue reconstruction of the severely comminuted atrophic mandible fracture case report. J Cranio-Maxillofac Surg 2003;31:296–8.  Scott RF. Oral and maxillofacial trauma in the geriatric patient. In: Fonseca RJ, Walker RV, editors. Oral and maxillofacial trauma, 2nd edition, vol. 2. Philadelphia: Saunders; p. 1045– 72.  Spina AM, Marciani RD. Mandibular fractures. In: Fonseca RJ, Marciani RD, editors. Oral and maxillofacial surgery, vol. 3. Philadelphia: Saunders; p. 103–7  Ellis E. Treatment methods for fractures of the mandibular angle. J Craniomaxillofac Trauma 1999; 28:243–52.  Madsen MJ, Haug RH. A biomechanical comparison of two techniques for reconstructing atrophic edentulous mandible fractures. J Oral Maxillofac Surg 2006;64:457–65.  Louis P, Holmes J, Fernandes R. Resorbable mesh as a containment system in reconstruction of the atrophic mandible fracture. J Oral Maxillofac Surg 2004;62:719–23.  Newman I. The role of autogenous primary rib grafts in treating fractures of the atrophic edentulous mandible. Br J Oral Maxillofac Surg 1995;33:381–7.