Long-term results of trismus release in noma patients


Noma, also known as cancrum oris, is an infectious disease that results in a loss of orofacial tissue, due to gangrene of soft and bony tissue. It is especially seen in young children in the sub-Saharan region. Among the sequelae of patients who survive noma, trismus is one of the most disabling. This retrospective research studied the long-term results of trismus release in noma patients. Thirty-six patients could be traced in the villages and were included in the study. The mean mouth opening in this group was 10.3 mm (95% CI: 7.0; 13.6 mm) and the mean period after discharge from hospital was 43 months. Better mouth opening was observed in patients who continued physiotherapy after discharge, were older, and those with a ‘soft’ (vs. ‘hard’) inner and outer cheek on palpation. The result of trismus release in noma patients in the long term was extremely poor in this study.

Noma, also known as cancrum oris, is a devastating infectious disease that results in a loss of orofacial tissue, due to gangrene of soft and bony tissue. It particularly affects children in the weaning period, with malnutrition, bad oral hygiene and a compromised immune system due to another infectious disease, such as measles .

Noma virtually disappeared from Europe and the USA by the end of the 19th century, but is still seen in Third World countries, especially in the Saharan belt . In 1998, the WHO estimated the global incidence as 140,000 new cases each year. In 2003, the incidence in the sub-Saharan region was estimated to be 25,600 cases . The estimated mortality (up to 90%) is high because only a few patients seek health care in the acute stage of the disease .

The most common sequelae for patients who survive noma are facial mutilation, incontinentia oris, trismus, feeding and speech problems, interference with growth of the facial skeleton, deformed dentition and social isolation . Trismus is one of the most disabling sequelae, resulting in difficulties in speech, mastication, social feeding habits and maintenance of oral hygiene . In most cases, surgical release of the trismus is necessary, but there are no recent studies on the long-term results of these operations.

The technique used for the release of trismus depends on its severity and is influenced by the localisation and extent of the lesion. The term ‘trismus’ is used here to describe the inability to open the mouth to the normal extent, but in cases of noma this inability is not caused by trismus only. Ankylosis and hypertrophy of the coronoid process are also involved . Figure 1 summarizes the processes that are involved in noma. In this paper, the term ankylosis is used when a patient is unable to open their mouth at all and the term ‘trismus’ is used to describe the process that limits the ability to open the mouth to a normal range in patients who survive noma.

Fig. 1
The processes that can immobilize the mandible in noma.

In Sokoto, in the sub-Saharan region of North Nigeria, the state government and the AWD Stiftung Kinderhilfe (a German child foundation) started a noma project in 1995 and built the Noma Children Hospital Sokoto (NCHS) . Western teams of experts frequently come to operate on the noma patients. One of their objectives is release of the trismus. Information on the noma patient is registered during the admission and the short-term outcome of trismus release seems to be satisfactory. After discharge contact with the patient is lost and the long-term outcome is not known. To aid future evidence-based treatment, a retrospective study was performed on the long-term results of the release of trismus in patients who have survived noma and the factors that influence the outcome.

Materials and methods

To recruit patients, the NCHS database was searched. Files with the terms ‘noma’ and ‘trismus’ were identified and the following data collected: address; gender; age; age of onset; date of admission; stage of noma; team number; information on the operations; pre- and postoperative mouth opening; postoperative physiotherapy; and date of discharge. The NOITULP classification, introduced by M arck in 1998, was used to determine the extent of defects in the noma patients . In this classification, ‘ T ’ describes the loss of capacity to open the mouth, ranging from T 0 a mouth opening of 40 mm or more, to T 1 < 40 mm, T 2 < 30 mm, T 3 < 20 mm and T 4 < 10 mm. The other letters in the classification describe the defects of the nose, outer cheek, inner cheek, upper and lower lip.

The criteria for selecting patients were: the subject is a noma patient; the patient had been discharged from the hospital at least 6 months before selection; there was a documented T value; the patient had trismus with a T value of at least T 2 ; trismus release was documented; and the patient lived in Nigeria.

The selected patients were traced by means of a photograph and name in the villages where they lived at the time of their treatment. The mobility of the mandible was assessed by maximum mouth opening. Movement in the horizontal plane, protrusion and retrusion and mobility to the sides, were assessed by measuring the difference between two fixed points. These points of fixation differed from gingiva or teeth. The inner and outer cheek on the affected side of the face were classified as ‘hard’ or ‘soft’ by means of palpation. The patient was asked whether they continued physiotherapy after discharge from hospital and whether there were problems with speaking, eating and hearing.

The data were processed in Microsoft ® Access 2000 and in SPSS 15.0, 2006, for statistical analyses. The statistical significance was calculated using Student’s t -test and significance was defined as P < 0.05.


Two hundred and six files in the NCHS database contained the terms ‘noma’ and ‘trismus’, but only 130 files were present in the hospital and could be reviewed. Of these, 63 patients fulfilled the selection criteria and were visited in the field. In a journey of 1900 miles to 45 villages, 36 patients were found and included in the study. The remaining nine patients had given incorrect addresses, were not present at the time of the visit or were not traceable. The 18 people who were not visited lived too far away from Sokoto. Of the 36 patients included, 23 (64%) were women and 13 (36%) were men and the mean age at the time of the last operation was 19.9 years (95% CI: 15.2; 24.6).

The long-term result was compared with the preoperative T value. This value was chosen, because data about the preoperative mouth opening in mm and the postoperative mouth opening were missing in most cases. Of the 36 patients, 30 (83%) had a preoperative T value categorized as T 4 , five (14%) as T 3 and one (3%) as T 2 . The measurements of the maximum mouth opening in mm during the visit are listed in Table 1 . It ranged from 0 to 39 mm with a mean of 10.3 mm (95% CI: 7.0; 13.6 mm). 14 patients (39%, [95% CI: 23.1; 57%]) had an improvement in T value, 20 patients (56%, [95% CI: 38.1; 72%]) had an equal T value and two patients (6%, [95% CI: 0.7; 19%]) had a decline in mouth opening and had a higher T value. The relation between preoperative mouth opening and the mouth opening during the visit is shown in Fig. 2 . The period after discharge from hospital varied from 12 to 78 months, with a mean of 43 months. There was no correlation (Pearson correlation 0.136) between the period of discharge and mouth opening during the follow-up.

Table 1
Frequency and percentage of mouth opening found during the visit.
T value mm Number of patients Percentage Cumulative percentage
T 4 0 6 16.7 16.7
1 2 5.6 22.2
2 3 8.3 30.6
3 2 5.6 36.1
4 2 5.6 41.7
6 2 5.6 47.2
7 1 2.8 50.0
9 1 2.8 52.8
T 3 13 3 8.3 61.1
14 2 5.6 66.7
15 2 5.6 72.2
16 1 2.8 75.0
17 1 2.8 77.8
18 2 5.6 83.3
T 2 20 2 5.6 88.9
21 2 5.6 94.4
T 1 34 1 2.8 97.2
39 1 2.8 100.0
Total 36 100.0

Fig. 2
Relation between the preoperative T value and the T value found during follow-up. Each group of bars represents a preoperative T value group and each different marked bar the T values of that group during the visit. The values at the top of the bar indicate how many patients continued physiotherapy.

Table 2 summarizes the measurements concerning the movement of the mandible in the horizontal plane, and the factors that influenced mouth opening in the long term, such as the consistency of the inner and outer cheek and the continuation of the physiotherapy. The mean age of the patients who did not continue physiotherapy after discharge was lower than that of those who did: 14 years vs. 24 years ( P 0.023).

Table 2
Movements on the horizontal plane and factors that possibly influence mouth opening in the long term.
Variable Percentage (%) Mean mouth opening (mm) P
Both sides 17 21.0
One side 42 8.3 0.014 *
None 42 8.0 0.011 *
Protrusion and retrusion
Possible 17 10.8
Not possible 83 7.7 0.477
Inner lining
Hard 47 6.1
Soft 53 14.1 0.011
Outer lining
Hard 17 4.0
Soft 83 11.6 0.083
Continued after discharge 42 15.1
Did not continue after discharge 58 3.7 <0.001
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Feb 8, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Long-term results of trismus release in noma patients
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