Relevance of post-operative radiographs in maxillofacial fractures- A retrospective multicentre study

INTRODUCTION

Open reduction and internal fixation for maxillofacial fractures is one of the most common procedures performed by a maxillofacial surgeon. Ordering post operative radiographs has become a part of treatment protocol in most practices. This is more prevalent in teaching hospitals where evaluation of post-operative radiographs is considered to be a part of academic curriculum. However, the role of and need for post-operative radiographs is increasingly being debated. Several practitioners believe that post-operative radiographs do have a role to play and can be useful tools in better management of trauma patients.1

Several regulations and legislations seek to limit unnecessary exposure of patients to ionizing radiation. These regulations emphasize on the justification of radiographic examination through clinical diagnostic information obtained that is relevant and useful. 2-4 We therefore decided to do a retrospective study to evaluate the need and usefulness of post operative radiographs. The aim was to assess whether post-operative radiographs had an impact upon the post surgical clinical course of a patient with maxillofacial injuries.

Method:

For the retrospective study, data during the period Jan 2012 to June 2014 (30 months) was collected mainly from two dental teaching hospitals. One institution was located in the heart of a major Indian city and the other one at a town located about 200 kilometres from a state capital. The two institutions were chosen to include both the urban and semiurban/rural population in the study. This was done to eliminate cost or availability of resources as possible biases to the results. Both institutions have a protocol of ordering relevant post-operative radiographs a day after surgery.

Case files/records of with maxillofacial fractures which had follow-up records for atleast 3 weeks post surgery were selected and included in the study. Patients with complex craniofacial trauma were excluded. The search yielded 343 case records of patients treatedwith open or closed reduction for maxillofacial fractures done under GA or LA.All postoperative radiographs were ordered within 48 hours post treatment. A review form was prepared for each case report to record the following:

• Patient details

• Nature of injury and the treatment done (with date)

• Post-operative radiographs ordered (and on which post-op day)

• Relevant findings on post-operative radiograph (yes/no)

• If yes, then nature of defect and relevant clinical finding

• Post surgical treatment plan based on:

a) Radiographic discrepancy noted but active intervention not deemed necessary

b) No radiographic discrepancy but clinical findings relevantenough to merit surgical re-intervention.

c) Surgical intervention based purely on radiographic findings with minimal or no relevant clinical findings

• Surgical re-intervention undertaken It was decided to include patients who were re-treated either conservatively or surgically based on post-operative radiographic finding within one month of the initial surgery. Any decision to intervene after this period was deemed not to have been taken on the basis/findings of the immediate postoperative radiograph. Conservative options included guiding elastics in case of occlusal discrepancies, systemic corticosteroids in cases of neurological disturbances.

Results:

A total of 343 case records were examined. 240 (70%) cases were treated under GA and 103 (30%) were treated under LA. 310 (90%) patients required open reduction and the rest were treated with closed reduction techniques. Break up of fracture configuration treated is depicted in table1.

Discrepancies noted in the post-operative radiographs are depicted in table 2. No patient was re-operated because of inadequate reduction noticed on the post-operative radiograph. In one patient, a second surgery was needed within one month of the initial surgery because of infection. Post-operative radiograph was of no help in determining the treatment plan for that patient.

Findings of the post-operative radiograph played a role in altering the post surgical treatment plan in 3 patients. Two were mandibular fracture cases. The other was a case of zygomatic arch fracture.

Case 1: patient had fracture in the right parasymphysis region. He was treated with open reduction and internal fixation under LA with titanium miniplates. The post operative radiograph (orthopantomogram) revealed that the superior plate impinged on the mental foramen (Photo 1). The patient complained of persistent paresthesia in the right half of the lower lip and part of his chin even after 15 post-operative days. A decision was taken to reposition the plate under LA and relieve the possible compression on the mental nerve.

Case 2: patient had fracture in the right parasymphysis region with an undisplaced left subcondylar fracture. He was treated with open reduction and internal fixation under LA with titanium miniplates. Post operative occlusion obtained was satisfactory. However the post-operative radiograph (orthopantomogram) revealed a medially displaced left condylar segment. A decision was taken to explore the left condylar region and to reduce and fix the fracture. The intended aim was to restore anatomic continuity and to ensure maintenance of vertical facial height and to prevent any future occlusal disturbances and imbalances in the biomechanical actions of theconcerned muscles because of a displaced condylar segment.5

Case 3: patient had an undisplaced right infra-orbital rim fracture and fracture of the right zygomatic arch with flattening of the right cheek. He was treated with elevation of the right zygomatic arch under LA. Post-operatively, the patient’s appearance seemed satisfactory but the post-operative Submentovertex (SMV) view radiograph (Jug Handle view) showed virtually no change in the position of the reduced arch. After a couple of days, flattening of the cheek along with facial asymmetry was noticed. The initial fullness was attributed to oedema after the fall or because of the surgery. Then a decision was taken to reelevate the arch under LA. Although the decision was taken on the basis of clinical appearance, the SMV played a crucial role in deciding the action to be taken.

Discussion:

Ordering post-operative radiographs has become a part of the treatment protocol in many institutions. This practice is more prevalent in teaching hospitals where a part of or entire procedures are done by trainees and senior residents under the supervision of senior consultants. However, their actual usefulness has been a topic of debate. Customs and age old protocols should not be allowed to dictate the need for postoperative radiographs in today’s day and age of evidence based practice.

There have not been many studies which have tried to assess the need for postoperative radiographs and even fewer studies looking into the need for such radiographs for fractures in maxillofacial region.1,6-8 Childress and Newlands8 retrospectively reviewed the postoperative panoramic radiographs of patients with fractured mandibles over 5½ years, to see if the films aided detectionof short-term postoperative complications. They concludedthat they could find no support for the routine use of postoperative panoramic radiographs. MK Jain and Mohan Alexander6 tried to determine the reason behind the practice of ordering post-operative radiographs in south India and to assess whether they are actually needed. They too concluded that not all cases required post-operative radiographs.

Ours is a multicentre study for which we collected data from case records of patients with maxillofacial fractures during the period Jan 2012 to June 2014 (30 months). Our sample size of 343 patients included people from urban, semi-urban and rural areas. This was done to eliminate bias which could be because of cost issues, availability of resources and possible patient apathy in rural centres as compared to urban centres. We included patients with all kinds of maxillofacial fractures except those with complex craniofacial injuries. We found that only 3 out of 343 patients (0.9%) were re-operated on the basis of post-operative radiographic findings.

Post-operative radiographs do have some indications and uses. They could help to detect to detect gross errors or defects in reduction of fractures which merit immediate correction.1They could help to predict potential complications which if treated early could be avoided. They could have an important role to play in medico-legal cases1. Post operative ‘check’ radiographs can help in assessing the adequacy of plating and efficacy of the reduction achieved. This becomes an important tool for personal audits especially for trainees and budding surgeons. In several academic institutions, these radiographs are used as teaching tools1 and form a part of treatment protocol.

Post-operative radiographs have a definite indication in patients treated with closed reduction for fractures. In such cases adequacy of reduction can be assessed with such radiographs along with clinical outcomes like state of occlusion.

We believe that intra-operative assessment and immediate post-operative clinical findings are better indicators to determine further treatment or need for changes in the preoperative treatment plan. Clinical indicators like mal occlusion, altered sensations, flattened cheek(s), diplopia, restriction of eye movements and asymmetry are better predictors of the adequacy of fracture reduction than post operative radiographs.

The assessment of the position of the miniplate was the most common justification of taking postoperative radiographs. However we accept J.A. Durham, A.W. Paterson et al’s view that intra-operative assessment should suffice to know the position of miniplates and that 2 dimensional radiographs are not good indicators of the positioning of screws and potential damage that may have been caused to any tooth.7

The major disadvantages of ordering postoperative radiographs include high costs, unnecessary exposure to ionizing radiation.1 Cost factor plays an important role in the semi-urban and rural areas. Ordering postoperative radiographs just as a part of protocol without any clinical justification can place an unnecessary economic burden patients belonging to the middle and lower economic strata who struggle on several occasions to even pay for the surgery and plates used. Cost for a panoramic radiograph in both the institutions is 300 INR (about 5 USD). PA view of the Mandible and a Para nasal sinus view also costs around the same.

The biggest concern is the exposure to ionizing radiation.. Every exposure carries a risk. The National Radiological Protection Board guidelines4 on diagnostic medical exposuresstate that ‘‘investigations utilising ionising radiations offer potential benefits... however, such radiation is associated with an increased risk in the long term of malignant disease...there is also a putative but low risk of serious hereditary disease...The probability of occurrence of these adverse effects is directly proportional to the level of exposure, without any dose threshold. It is necessary to considerthe potential harm...arising from even thelowest levels of absorbed radiation dose and toavoid those exposures which have no merits”.

Some surgeons believe that immediate postoperative radiographs serve as important guidelines for future surgeries or corrections that may be required especially in cases with severe facial injuries and multiple bone fractures. Although this may be true in certain cases, however we believe that clinical evaluations serve as better indicators for corrective surgeries. Radiographs can be ordered prior to corrective/secondary surgeries if the surgeon feels the need for it rather than subjecting all polyfacialtrauma patients to unnecessary radiation exposure for the purpose of post-operative radiographs which may or may not prove useful later on.

The use of post-operative radiographs as important records in medico-legal cases is also being debated. It has been stated by the Royal College of Radiologists10 that ‘‘if, as a result of careful clinical examination you decide that a radiograph is not necessary for the future management of the patient, your decision is unlikely to be challenged on medico-legal grounds... ’’. Proper follow up notes with meticulous clinical documentation and photographs serve as adequate data for medico-legal documentation.

The dose of radiation exposure from diagnostic radiographs is low. A patient with a fractured mandible is exposed to 0.03 mSv for a posteroanterior mandibular radiograph and 0.026 mSv for a dental panoramic tomography.7 So it is very difficult to attribute it as an etiological agent for cancer. When a model of cumulative risk of radiation induced cancer is applied to these doses, an estimate of the attributed risk of developing cancer is derived. It is suggested that in Australia about 431 cancers a year (1.3% of all cancers) could be attributed to diagnostic radiographs and that inthe United Kingdom around 0.6% of all cancers could also be so attributed.9A few studies have hinted at the possibility of tumours in the brain and salivary glands because of exposure to dental radiography.11-13 Although no substantial evidence still exists to prove the assumed association there are enough indications to avoid unnecessary exposure to diagnostic radiation.

Certain studies point at a delay in discharge of the patient because of the time taken to get a post-operative radiograph and subsequent analysis of the film.6 But in our retrospective analysis, we did not find any comment on it in any of the case records though a possibility of delay in discharge cannot be ruled out.

Conclusion:

Post-operative radiographs should be ordered only when specific clinical indications exist or when the surgeon feels that such a radiograph can be a useful predictor of potential post-operative complications. The use of post-operative radiographs as a part of protocol or a ‘custom’ should be discouraged. This is especially relevant in cases with mandibular fractures and fractures of zygomatic arch where the diagnostic value of these post surgical radiographs is questionable at best. The surgeon should rely on intra-operative assessment, post-operative clinical findings and progress of patient as tools for personal audit rather than post-op films. We also believe that the patient must be informed about the reason for ordering postoperative radiographs and a consent should be obtained if they are being taken for academic or ‘record keeping’ purposes. In this day and age of evidence based practice, the principle of ‘as low as reasonably achievable’ ALARA14 should be followed while deciding on the need for post-operative radiographs

Declarations:

The authors would like to state that they have no potential or actual conflict of interests in connection with the study. The authors also received no financial support or grants for the conduction of this study.