Trauma; preprostheticsurgery J. G. Williams 1, J. I. Cawood 2
Effect of intermaxillary fixation on pulmonary function
1Department of Respiratory Medicine, Halton General Hospital, Runcorn, and 2Maxillofacial Unit, Royal Infirmary, Chester, U.K.
J. G. Williams, J. I. Cawood." Effect of intermaxiIlary fixation on pulmonary function. Int. J. Oral Maxillofac. Surg. 1990; 19." 76-78. Abstract. A study to measure the pulmonary effects of intermaxillary fixation (IMF) demonstrated that this technique produces a significant degree of airway obstruction. This may be dangerous to patients with limited respiratory reserve due to chronic obstructive airways disease. The impairment of p u l m o n a r y function can be assessed pre-operatively and should be estimated in high risk patients. Alternative management of stabilization of jaw fractures that avoid I M F should be considered in such patients.
Intermaxillary fixation (IMF) is the traditional method of treating fractures of the h u m a n jaw 5 despite accounts of hazards to the airway resulting from the procedure 4. The aim of this study was to attempt to quantify the effect of I M F on pulmonary function in particular a) inspiratory and expiratory flow rates and b) lung volumes.
Material and methods Seventeen healthy volunteers took part in the study. They were all non-smokers and had no evidence of any chest disease. All subjects performed maximal inspiratory and expiratory exercises through a face mask under conditions of normal airways patency, teeth in occlusion to simulate IMF and teeth in occlusion plus nasal obstruction produced by nose clips. A typical flow volume loop used in the study is shown in Fig. 1 from which the following measurements were made: (i) Forced vital capacity (FVC), i.e. total volume of air expelled during a forced expiration. (ii) Forced expiratory volume (FEVI) i.e. volume of air expelled during the first second of expiration.
Key words: intermaxillary fixation; pulmonary function. Accepted for publication 22 November 1989
LUNfi ,VOLURE FLOW RATES (L/sic)
Fig. 1. A normal flow volume loop TLC=Total lung capacity; PEF = Peak expiratory flow; RV = Residual volume; MIFs0 and MEFs0: see text.
(iii) FEV % = FEVI x 100 FVC (iv) Peak expiratory flow (PEF) (v) MIFs0 and MEFs0: inspiratory and expiratory flow rates when the lung volume is the residual volume plus 50% of the vital capacity.
Results Occlusion of the teeth in the 17 test subjects produced a significant decrease in all measurements other than the FVC
Fig. 2. Effect of teeth occlusion on (FEV%).
Effect of intermaxillary fixation on pulmonary function Table 1. Results Lung function measurements (___SEM)
Mouth open Mouth closed
FEV 1 (1)
4.37 ___0.29 4.37 +0.33
3.37 _+0.14 1.86 -+0.14 p