38. Management of Oral Sub-Mucuos Fibrosis (OSMF) with Trismus
OSMF has been endemic in south and south east Asia due to the habit of chewing tobacco mixed with lime (calcium hydroxide) wrapped in Betel leaves together with areca nut. What alarmed health professionals in the last quarter century in India was the sudden increase in the incidence of this condition simultaneously with a highly advertised and profitable business of combining the above ingredients with addition of substances which were even more corrosive but were sweetened and then sold in attractive sachets. Some states in India have now banned the production and sale of such combinations and anecdotally at least in the experience of the compiler of these short notes there has been a fall in the incidence of OSMF. The corrosive effects of these substances are known to lead to leukoplakia and Oral Cancer but that OSMF leads to malignancy has not been proved statistically. Rarely OSMF can occur without a known cause. Also like in malignant disease the fact that abuse of oral corrosive substances does not invariably lead to OSMF hints at a genetic resistance to this crippling condition. Clinical examination reveals a stretched tight pale mucosa on one or both sides in the oral cavity mainly in the buccal sulcus depending upon where the substance was kept as it was being chewed. Symptoms include burning of the mouth and discomfort occasionally loss of taste and intolerance to spicy food but the patient usually seeks help because of the inability to open the mouth fully. When the inter-incisor distance is measured with a ruler the severity of the condition can be graded; severe – 1 cm or less, less severe – 1-2 cm, Moderate – 2-3 cm and mild or early 3-4 cm. Normal inter incisor distance when the mouth opens fully is more than 4 cm. Sudhanshu Kothe Plastic and reconstructive surgeon from Nagpur, India has perhaps one of the largest series of the treatment of this condition and has kindly sent voluminous information on the subject on which this article is based.
- Before undertaking the treatment of OSMF it is very essential that the patient stops the abuse of every kind of corrosive stimulant through the oral route including alcohol.
- Malignancy of the Oral mucosa is always a possibility and might be present together with this condition and a thorough examination including indirect laryngoscopy should be undertaken when possible (see following paragraphs).
- The discovery of a suspicious malignant lesion changes the paradigm of the way the patient is treated because it might involve excision and is followed by an entirely different kind of reconstructive procedure. Therefore the patient needs to be warned that the examination of the mouth is always incomplete in OSMF due to trismus and that a malignant ulcer may be revealed when the trismus is surgically released which will require excision, frozen section biopsies and if proved positive, more extensive flap cover.
- OSMF leads to poor nutrition (anemia and hypoproteinaemia) which needs to be corrected prior to anaesthesia and surgery.
- Mild trismus might be arrested if substance abuse is stopped and some cases may be somewhat relieved with local injection of corticoids and intensive physiotherapy.
- In the more severe forms some kind of surgical release with or without a flap cover is essential.
- When undertaking surgery, anaesthetic considerations are very important because oral intubation is almost always difficult. It may be possible to introduce a laryngoscope in the mouth but the laryngeal inlet is rarely visible and a blind or guided nasotracheal intubation with the help of a naso-endoscope has to be attempted with all preparations for a tracheostomy at hand. In fact in some cases a tracheostomy is chosen as an elective procedure through which tracheal intubation is done and anaesthesia is maintained.
- The judgment as to if only incising the fibrosed mucosa will suffice depends on the severity of the lesion. In mild cases when, an almost full opening of the mouth is achieved by releasing the mucosa, an inference can be drawn that the condition is of comparatively recent origin and that inter-maxillary, secondary contractures of other soft tissues has not occurred. The secondary contracture usually involves the masseter and / or its fascia as well as the temporalis tendon which, if secondarily contracted, will not allow the coronoid process to move (see Fig. 1-3 at the end of the paragraph). The masseteric fascia can be released through the oral incision high upon the maxilla. When releasing the mucosa, it helps greatly if the incision is taken in the depths of the mandibular sulcus as well as high in the maxillary sulcus. Not infrequently the adjacent areas of the soft palate might be involved and will need to be incised up to its muscle by going around the last upper molar tooth. This procedure usually needs to be done bilaterally and the ensuing defects are not very broad. The advantage of this type of release is that a bi-pedicle flap in situ is created in the centre of the cheek on both sides which helps rapid epithelialisation of the raw areas. Physiotherapy can be begun on the very next day because flap cover has not been done and there is that much safety in terms of not traumatizing or twisting the newly placed flap. Occasionally in trying to release the temporalis fascia/tendon, a coronoidectomy might have to be performed.
- In the more severe forms flaps are inevitable and the choice depends on the site and size of the defect. A thick mucosal flap from the medial side of the mandible extending on to the lateral surface of the tongue based posteriorly and swung around the last molar will usually suffice for defects of 1.5 cm broad and will reach up to the angle of the mouth. This can be done bilaterally and the defect created by the harvest of the flap usually epithelialises rapidly. Long random pattern flap from the anterior surface of the tongue based in the posterior one third of the tongue can also be swung around the last molar to bridge defects of the central part of the cheek. The defect in the tongue can be closed primarily and does not lead to any morbidity. The flap of the oral mucoperosteum of the hard palate based on the greater palatine artery (hemi-flap on either side) or a flap of the whole of the mucoperiosteum based on only one of the two greater palatine arteries can also be raised to cover a larger defect on one side (Fig. 4-5).
- However for larger defects the platysma myocutaneous flap located in the supra-clavicular area and based on a broad swathe of the platysma separated from the skin by tunneling provides an excellent, supple flap of just enough thickness to cover the defect and can be used bilaterally. Since at least some of the more severe forms of SMOF cases require a tracheostomy, care has to be taken by keeping the tracheostomy incision in the midline and if possible vertical so that it does not impinge on the area from where the flap is cut. This flap requires careful dissection and must include the deep fascia below the platysma muscle which forms the long base of the skin paddle. Any separation of the skin from the thin paddle of the platysma has to be strictly avoided so as not to injure the perforators that enter the skin. Sudhanshu Kothe with whose material this compilation was done has noticed that the flaps do better if the external jugular vein is included along the base of the flap (Fig. 6-11).
- Post-operative recovery: Flaps within the oral cavity have their own problems because they are bathed in saliva though arguably in cases of SMOF this is likely to occur to a lesser degree. These intra-oral flaps are also difficult to observe and tend to struggle more than the ones on the exposed parts of the body and many a time it is difficult to assess the degree of the depth and area of loss in the flap. They therefore need to be debrided at a slightly later stage after they are put in as compared to other extra oral flaps. On the other hand epithelialisation in the oral cavity is very rapid and in the case of OSMF the import of vascular tissue such as the temporalis fascia alone as a flap has also shown rapid re-epithelialisation (see figures in the latter part of the chapter).
- Notwithstanding adequate surgical correction, physiotherapy, both active and passive is crucial in the post-operative period to overcome secondary contractures and to maintain a good opening of the oral commissure and this may have to be done for the rest of the patients’ life. Printed below are some appliances which will help in the effort to keep the commissure open (Fig. 13-16).
- A reference has been made in para 11 in which only a facial flap has been brought into the recreated defect in the oral cavity. This method succeeds on the surgical principle that oral wounds re-epithelialise rapidly as long as the bed of the wound is healthy and does not have a neo-plastic or a necrotizing element within it. The photographs shown below have been provided by Nitin Mokal, Craniofacial surgeon from Mumbai who has been a valuable contributor to these short notes earlier as well (See Fig. 17-25).
- Dr. Borle, a maxillofacial surgeon and the registrar of the Datta Meghe institute of Medical sciences in Wardha in western Maharashtra, India, employs an ingenious flap to line the intra-oral defect from the naso-labial area (see Fig. 26-36).
This chapter shows what can be achieved in cases of OSMF. However the reality might be different to an extent because here in this condition a reconstructive surgeon is treating a disease rather than a defect or a deformity. Once begun, the pathology of OSMF is relentless in some cases and may continue even after substance abuse is stopped. Post-operative compliance is not always good vis-à-vis physiotherapy. And if physiotherapy is discontinued before the secondary soft tissue contractures are overcome, the mouth tends to contract again. Add to that the problems of keeping intra-oral flaps in good health. All this leads to unsatisfactory results on long term follow-ups in some cases of this dreadful condition and perhaps this is one disease that is best prevented rather than treated.