CASO CLÍNICO

 

Post surgical orthognathic of upper maxilla pseudoarthrosis. Proposed clinical study

Pseudoartrosis maxilar superior post-cirugía ortognática. A propósito de un caso clínico

 

 

I. Zubillaga Rodríguez¹, I. Heras Rincón², J.J. Montalvo Moreno³

¹ Médico Adjunto
² Médico Residente
³ Jefe de Servicio
Servicio de Cirugía Oral y Maxilofacial. Hospital Universitario 12 de Octubre. Madrid. España

Correspondence

 

 

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ABSTRACT

Introduction. The development of rigid internal fixation in the management of facial fractures over the last 25 years increased not only the number of available treatments but also, when incorrectly applied, the types of complications arising.
Material and methods. We present a new case report of upper jaw pseudoarthrosis after a convencional treatment of orthognatic surgery ( osteotomy type LeFort I).
Discussion. Pseudarthrosis-nonunion can result after incorrect treatment of facial fractures with titanium miniplatesscrews. When we review the publishing literature, we find that the correct treatment of this potential pitfalls has not changed significantly during last years. The aim is the mechanical immobility of the created fracture. Sometimes we must harvest cancellous bone graft to complete the treatment. We discuss the different terms related to anomalies in the ossification.
Conclusions. Inadequate stabilization of fractures by either conservative or operative methods often leads to infection, pseudoarthrosis or both. To promote healing of both infections and pseudarthrosis, absolutely stable fixation of the fragments is necessary. Depending on the defect zones that may develop, the osteosynthesis or reosteosynthesis that is usually necessary must be accompanied by a graft of autogenous cancellous bone.

Key words: Pseudarthrosis; Delayed union; Orthognatic surgery.

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RESUMEN

Introducción. La introducción de nuevos métodos de fijación rígida en el tratamiento de fracturas faciales durante los últimos 25 años ha incrementado no sólo el arsenal terapéutico disponible sino también, cuando no es correctamente utilizado, el tipo de complicaciones postquirúrgicas.
Material y métodos. Presentamos un nuevo caso clínico con el diagnóstico de pseudoartrosis de maxilar superior tras la realización de una osteotomía convencional tipo LeFort I en el seno de un procedimiento de cirugía ortognática.
Discusión. El retardo de consolidación- pseudoartrosis puede resultar tras el tratamiento incorrecto de fracturas faciales con miniplacas-tornillos de titanio. Sin embargo, y tras revisar la literatura existente, el tratamiento de dichas complicaciones no ha variado de forma significativa durante los últimos años. El objetivo es la inmovilización mecánica en el foco de fractura afecto. En ocasiones, y dependiendo del tipo de consolidación obtenida, se necesita recurrir a la obtención de injertos óseos antólogos. La clasificación clínica de los defectos-consolidaciones óseas anómalas es a menudo arbitraria. Existe un amplio espectro de definiciones que describen condiciones concurrentes simultáneas e implicaciones funcionales determinadas por la localización anatómica. Se discuten los distintos conceptos relacionados con la consolidación ósea.
Conclusiones. La estabilización inadecuada de las fracturas con tratamiento conservador o métodos de fijación rígida conduce a infección, pseudoartrosis o ambos. La solución pasa por por la fijación estable de la fractura. Dependiendo del defecto creado, la osteosíntesis o reosteosíntesis que es necesaria debe ser acompañada por un injerto de hueso antólogo esponjoso, restaurando la oclusión dental adecuada.

Palabras clave: Pseudoartrosis; Retardo de consolidación; Cirugía ortognática.

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Introduction

The development of rigid internal fixation in the Management of facial fractures over the last 25 years increased not only the number of available treatments but also, when correctly applied, the types of complications that arise. Delayed union/Pseudarthrosis (non union) can result after incorrect treatment of facial fractures with titanium mini plate screws.

However, when we review the published literature, we find that the correct treatment of these potential pitfalls have not significantly changed over the past few years. The aim is the mechanical immobility of the center of the created fracture. Sometimes, depending n the type of obtained consolidation, we resort to obtaining bone grafts.

The majority of the clinical cases described in relation to abnormal ossification of the created fracture occur after inappropriate facial fracture treatment. Below we discuss the case of pseudarthrosis of the superior maxilla after a conventional orthognathic surgical procedure (Superior maxilla osteotomy type Le Fort I).

 

Clinical Case

Woman 39 years old, admitted for surgical treatment of a dental facial deformity. Her medical history showed that she was anemic and had no known allergies to medication. Upon physical examination the prognosis is class 3 molar and pseudo hipoplasia of the superior maxilla. A cranial orthopantography and teleradiography were carried out at the start of the corresponding cephalometric study.

After orthodontic treatment and extraction of the 4 wisdom teeth the patient underwent orthognathic conventional surgery. Under local anesthetic and nasal/tracheal tube for intubation and osteotomy type Le Fort I was performed. The bones were fixed with 2 premade titanium plates in both nasal maxilla outriggers 7mm of adavance , 3mm of anterior impaction and 5mm of posterior impaction, 1mm left rotation, partial inferior nasal septum resection, alar cinching and labial closure in V-Y fashion (Fig. 1).

The patient was released and had follow up external consults that showed episodes of repeating bilateral cellulitis. It started 6-9 months after the initial intervention. It was decided that the patient have the osteosythesis material removed one year after the initial intervention. This is done by reopening of the previous bilateral superior sub labial approach. Between operations we attempt not to move the third half of the face even with the Le Fort I osteotomy. This surgery is categorized as intolerance to osteosynthetic material.

One year after having periodic revisions in our external consults as well as with the orthodontist the patient reported exerting less force when chewing which allowed her to have solids in her diet. Clinical exploration showed light movement of the superior maxilla even with the Le Fort I, the patient maintains correct occlusion of class I. In the computed tomography of the facial middle third we observe an absence of superior maxilla consolidation with continued bone remedy of the Le Fort osteotomy (Fig. 2). Given the evolution time since the first intervention, a diagnostic hypothesis of superior maxilla pseudoarthrosis of this osteotomy is established. A decision is made to operate on the patient again in order to have definitive management of this complication. After blocking the elastic inter maxilla in class I and reopening the new superior sub labial approach (Fig. 3), the fibrous tissue in the bone margins of the superior maxilla osteotomy is removed (Fig. 4). The superior osteotomy maxilla is attached using two preformed titanium plates in which the advance is already established (Fig. 5) Spongy bone grafts are obtained from the right tibia using a medial approach (Fig. 6.) The grafts are then placed in the bone gap of the Le Fort I osteotomy, closing the defected area (Fig. 7). The anatomic pathological study of the localized fracture tissue shows a presence of cartilaginous cells with predominant fibroblast proliferation on the inside of the tissue.

After said intervention our consults show consolidation at osteotomy level, without its movement, with stable occlusion and an aesthetically pleasing aspect. In like manner complications after taking the graft from the tibia were not valued, being that the Rx control was favorable (Fig. 8).

 

Discussion

The clinical classification of unusual bone consolidation defects is regularly arbitrary. There is wide spectrum of definitions that describe concurrent simultaneous conditions and functional implications that are determined by anatomic position.¹ Failure to cure during the first 4-6 months after applied treatment is called lack of consolidation. The time varies according to the diverse reviewed series. Although the common time used as a reference is 6 months. This time is derived from the observations and histological study done on skeletal bone. Investigations into the maxilla bone consolidation of sheep show that the healing process is identical to that of the rest of the skeleton. Eventually there is an acceptable consolidated bone structure. Unlike the absence of union, there is potential for bone consolidation after additional immobilization and adequate reduction.

Fractures that do not have ossification after 6 months of post operative treatment are defined as pseudoarthrosis (some authors increase the limit to 8 months). The articulated joints where the chipped tissue discovered is fibrocartilage are false joints. While the bone formation continues in delayed union, this process ends in the cases that have a lack of union. There is a permanent lack of identifiable bone tissue in the center of the fracture. Experimental studies on animals (Schenk and Willenegger)² have shown that the chip of fibro cartilage is live tissue but it is not vascularized. The continual mobilization between the fracture fragments allows for fibro cartilage mineralization.

It's important to distinguish between hypertrophic pseudoarthrosis, where there is objectivable vascularization in bone callus formation, and atrophic pseudoarthrosis (non union without bone callus formation), related to the insufficient vascular contribution. Both types of pseudoarthrosis can be radio logically distinguished. In hypertrophic pseudoarthrosis the ends of the fragments are typically swollen( called elephant feet) while in atrophic pseudoarthrosis the ends simulate osteosclerosis. Depending on if the associated infected processes are intermittent or chronic, we see pseudoarthrosis either with contact or with a bone interfragment gap.

Osteomyelitis in the bone gap can occur after conservative or surgical treatment. Inadequate treatment of the fracture with internal fixation can result in inflammation. In any fracture where internal fixation was used, the definitive result can vary from bone union to a failed implant. If the failure happened before the end of the bone consolidation phase a radio logically visible callus will form with posterior repair of the bone gap after reabsorbtion of the ends of the fracture. Since the purpose of using plates and screws is to stabilize the broken bone fragments it should completely guarantee stabilization. Movement when foreign bodies are present generally implies not only pseudoarthrosis but also infection of the area.³

The absence of union implies an alteration to the normal bone healing process. While the conservative healing of treated fractures occurs mainly via callus formation from the periosteum, the objective of stable fixation of the fractures should be direct bone healing from the cortical and osteons directly bridging the bone gap.⁴ Mechanical instability alters this process and can provoke delayed consolidation or absence of union and, when foreign bodies are present, infectious processes.

Comminution at the center of the fracture involves added difficulty during fixation and because of this a higher incidence of pseudoarthrosis. Alteration of bone microcirculation and the simultaneous micro movements caused by insufficient stability are the main factors that lead to non union. It has yet to be established which of the components of internal fixation techniques (microcirculation or micro movements) are more important.

At the moment there is no doubt that applying osteosynthetic materials modifies microcirculation. Experiments performed on dogs and sheep showed that vascularization is reduced when using plates fixed with bi cortical screws (static compression). When reduction is inadequate and osteosynthesis is not carried out properly, the endostic vascularization is also altered because of the micro-macro movement of the bone fragments. Normal consolidation of the fracture gap can not take place through secondary treatment.⁵ Intrabone callus formation can aggravate the situation compressing the medullar cavities and additionally obstructing vascularization.

Furthermore, there can be many factors involved in the genesis of a lack of consolidation at the center of the fracture. These factors include failed antibiotic treatment, delayed treatment, the presence of many fractures, foreign bodies at the center of the fracture, patient age, metabolic alterations, and drug and alcohol abuse. These factors are usually associated with malnutrition and have adverse affects on bone treatment. Topazian and Goldberg⁶ show a high complication rate among indigenous populations that had complex postoperative clinical follow-up. The lack of cooperation and the hygiene deficit also make the prognosis worse. It is crucial to analyze the factors that cause failed consolidation and prevent adequate ossification of the fracture.

Osteomyelitis is another factor that should be independently considered as being involved in the lack of union. Lack of ossification and infection has been described as highly associated. Infection affects the bone treatment, reducing oxygenation, increasing fibroblast proliferation and delaying osteoblastic and osteoclastic activity. Formation of fibrous tissue prevails over bone deposit which creates a lack of consolidation.

Anderson and Alpert⁷ consider that infection can be avoided by establishing early surgical treatment.

Like many things, the best treatment is to prevent the problem before it starts. Reviewing the literature we find the number of patients with lack of consolidation at the center of the fracture to be 3%. That number is similar to the revisions performed 20 years ago.^7,8 This is surprising taking into account the evolution that has taken place in fixation methods that are available today (there are no series about patients with delayed consolidation in the upper maxilla, which means the statistics that we have were taken from lower maxilla fractures that were treated by surgical reduction or osteo synthesis).

Lack of fracture fixation or incorrect fracture fixation causes the local inflammatory process that takes place at the center of the fracture to endostically spread out. This happens as a result of limited perfusion of the sides of the bone fracture. As a result, osteomyelitis of the bone gap can be associated.

Regardless of whether there is osteomyelitis (often associated with lack of consolidation) around the center of the fracture or a over infected pseudoarthrosis the main goal should be the complete stabilization of the fracture. Review of clinical studies shows that the titanium plates can be used even in the center of an inflamed fracture if a proper technique is used.⁹ Three basic methods are recommended to handle these situations:

1. Specific Antibiotherapy.

2. In case of facial fractures, anatomic reduction.

3. Stable fixation with plates and titanium screws.

4. Use of autologous bone grafts taken from in the center of the fracture.

It is true that using an inter maxilla block as the only method of stabilization causes inflammation, but usually causes extensive reabsorbtion of the distal fragments of the fracture, which generally results in pseudoarthrosis. Internal fixation is important for complete treatment, assuring correct and stable occlusion.

Pseudoarthrosis treatment, especially when there is a bone defect, involves not only internal rigid fixation, but also autologous bone grafts that reconstruct the created bone gap. Any sequestrum o tissue fragment should be removed and the distal fragments of the fracture should be split (10).

Instability combined with weak osteosynthetic material or continual bone gap contamination in the presence of soft tissue defects regularly leads to chronic infected pseudoarthrosis. Abnormal fixation of just one screw can be responsible for chronic inflammation. The elected treatment in these cases usually consists of replacing osteo synthetic material with new titanium plates (according to the bridging zone, in some cases it is important to use plates that support the weight, for example the jaw) with antibiotic coverage or bone grafts if they are necessary.

 

Conclusions

Nowadays among the array of therapeutics available we count on precise methods of internal rigid fixation. Despite the sophistications mentioned, new cases of delayed bone consolidation at the center of the fracture that need complimentary treatment continue to arise. Prior to corrective surgery it is important to critically analyze the pathological process. When it comes time to propose a definitive treatment it is important to have complete and well documented physical examination, image techniques and knowledge of the surgical techniques in use.¹¹

The inadequate stabilization of fractures treated conservatively or with rigid fixation methods lead to infection, pseudoarthrosis or both. The solution requires a stable fixation of the fracture. Depending on the created defect, necessary osteo synthesis or re-osteo synthesis should be accompanied by an autologous sponge bone graft restoring appropriate dental occlusion.

 

 

Correspondence:
Servicio de Cirugía Oral y Maxilofacial
Hospital Universitario 12 de Octubre
Avda de Córdoba s/n
28041 Madrid. España
e-mail: ignaciozubillaga@yahoo.es

Recibido: 9.02.2007
Aceptado: 16.03.2009

 

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