The value of flexor hinge hand splints
P. J. R. Nichols *
S. L. Peach *
R. J. Haworth *
J. Ennis *
Based on a paper presented at the 6th Scientific Meeting of the United Kingdom National Member Society, I.S.P.O. Guildford, April 1978.
Functional hand splints have been in use in a number of spinal injury units in the USA since the early 1950s. The splints are designed to provide a pinch-grip either by harnessing wrist dorsiflexion or by external power. Such devices are little used in the United Kingdom.
This paper describes the results of late provision of 62 such splints in a Disabled Living Unit. A proportion of tetraplegic patients found such splints of considerable functional value.
It is estimated that some 30-60 patients each year would benefit from them if appropriate facilities for early fitting were available.
Injuries to the cervical region with spinal cord damage and consequent tetraplegia are a not infrequent cause of chronic disability in young people. With efficient initial management many survive and have a reasonable life expectancy. Such people have a varying degree of upper limb involvement depending upon the level and the completeness of the lesion. Their residual function ranges from very high lesions, with limited shoulder movement only to lower cervical lesions where only intrinsic hand function is impaired. In order to carry out the basic functions of eating, toilet and communication, and simple additional functions such as writing, washing and shaving, it is necessary to have some sort of prehension and movement of the elbow. These movements can be provided or simulated by ;
help from an attendant splints, gadgets and aids surgical reconstruction.
There are varying estimates as to the number of tetraplegics who would benefit from reconstructive hand surgery, from 5 per cent (Guttman, 1973) or 22 per cent (Lamb and Landry, 1972) to 60 per cent (Moberg, 1975). In the absence of a major surgical programme of reconstruction most spinal paralysis units rely upon simple cuff-like splints and a bimanual grip (Fig. 1 ) and use of the mouth for general activities of living for the majority of tetraplegics, backed up by a comprehensive social support system of care.
Functional hand splints
Since the early 1950s many spinal injury units in the USA have had a programme of functional splinting based upon a splint which harnesses remaining power of wrist extension (dorsiflexion) and by means of the splint transferring that power to a pinch grip, the pinch deriving from a three-point chuck made up of the thumb, index and middle finger (Fig. 2 ).
For those patients who do not have sufficient power to drive the splint by wrist extension the movements of the shoulder can be harnessed or external power (compressed C02 or electrical motors) can be used (Fig. 3 ). The earliest description of the appliances designed to convert wrist extension to pinch seems to be that of Bisgrove (1954). During the following decade the concept was developed and publicised from Los Angeles (Anderson and Sellars, 1958; Anderson and Snelson, 1962; and Nickel et al, 1963).
There have been several variations on the theme and a number of modifications (Bennet, 1957; Sabine et al, 1965; Engel et al, 1967; Goodman et al, 1970; McKenzie, 1973). The variations were to materials, the design of the linkages and finger cages, and the use of power (Long and Masciarelli, 1963 ; Barber and Nickel, 1969; Kelly and Hartman, 1971).
A number of centres have published the results of follow up studies of patients fitted with flexor hinge splints:
Rancho los Amigos Hospital, Downey, California (Runge, 1966)
Houston, Texas (Newson et al, 1969)
Younker Centre, Des Moines, Iowa (Spieker and Lethcoe, 1971) Highview Hospital, Cleveland, Ohio (Allen, 1971)
Wisconsin Rehabilitation Center, Madison (Knox et al, 1971).
Most of these follow up reviews cover experience extending over about a decade and report in each instance on about 50-100 patients fitted with the splints.
Although the presentation and the treatment programmes differ there are many similarities:
The splints are usually fitted as part of the initial hospitalization and subsequent rehabilitation programme.
The acceptance rate for the wrist-driven splints is about one half of those fitted, ranging from 43 per cent (Allen, 1971) to 90 per cent (Knox et al, 1971).
The acceptance rate for wrist driven splints is higher than for powered splints.
Acceptance and continual use appear to be related to many factors. The particular design of the splint, its efficiency and reliability; the amount of training and indoctrination in splint usage; "motivation" and ultimate resettlement of the patient are the important factors.
In the United Kingdom, although two descriptive reviews have appeared in the rehabilitation literature (Parrish, 1963; and Shah, 1974) there has been little enthusiasm for the splint. Even though Sir Ludwig Guttman concedes that both surgical reconstruction and flexor hinge hand splints have their place in the management of the tetraplegic hand (Guttman, 1973), his philosophy "if you cannot use one hand—use both hands" dominates most rehabilitation programmes.
Only one rehabilitation unit seems to be fitting these splints regularly and we have previously described our experience with a very limited follow up (Goble and Nichols, 1971 and Nichols, 1971).
This paper is a report of a follow up of 62 patients admitted to Mary Marlborough Lodge between 1964 and 1975 who were fitted with flexor hinge hand splints.
Material and method
Between 1964 and 1975 sixty-two patients admitted to Mary Marlborough Lodge disabled living research unit, for functional assessment and rehabilitation, were fitted with flexor hinge hand splints. All had completed major periods of hospitalization and rehabilitation in other units and the injury or illness had occurred many months and often years previously. Many of the patients were readmitted several times but a postal follow-up survey was carried out on all during 1976. Only 52 of the 62 patients were traceable. It is probable that the main reason for inability to trace was death.
Of the 62 splints manufactured and fitted, 44 were wrist-driven, 12 were gas (C02) powered, and 6 were spring assisted. The splints were constructed from kits of parts obtained from the USA of the type developed at Rancho los Amigos Hospital. Each splint was individually made and modified as necessary. The time for construction ranged from 38 to 80 hours depending upon the difficulties encountered (for example contractures or spasticity) and the modifications needed. Knox et al (1971) noted that the average time for manufacture in then-unit was 40 hours.
Modification to standard splint
The standard Rancho los Amigos splint (Fig. 4 ) with metal finger cages has been the basis of our splint programme. The commonest modification carried out has been the insertion of a radial deviation hinge (8 patients). In recent years we have changed from the "parallelogram" to the "ratchet" type of moving linkage (Fig. 5 ). Minor adaptations to cater for holding specific tools and devices for eating, writing, or leisure activities were provided for 9 patients.
Much of the information required was already available in the medical notes and workshops records and these were used to complete the main questionnaire. However a personal questionnaire was sent out to each patient and completed either by the patient or a relative or attendant.
Of the 52 traceable patients, 44 completed and returned this second questionnaire, a return rate of 85 per cent.
The details of the patients reviewed and the types of splints fitted are given in Table 1 , Table 2 and Table 3 .
The ages of the patients at time of fitting is shown in Table 4 . The time between onset of injury or disease and fitting of the splint is shown in Table 5 .
Wrist driven splints
The wrist driven splints were of the type originally designed for C5/6 spinal cord lesions. In our series 36 patients with spinal cord lesion were fitted with these splints. At follow-up 14 patients with tetraplegia due to spinal cord lesions were still using their splints.
Table 6 gives the details of the level of the lesion and the use of the splints at follow-up.
Table 7 indicates the activity for which the . splints are used.
Some patients who have remained functional users of wrist driven splints tend to use them for many hours a day but other patients use them for specific activities, for example writing or feeding, for short periods only. This group of patients have become dependent upon their splint for one or more activity. The length of
time between fitting the splints and the follow up is shown in Table 8 .
Two patients with other lesions were also fitted with wrist driven splints and the details are given in Table 9.
Spring assisted splints
Detailed records and follow up questionnaires were completed on 5 of the 6 patients fitted with spring-assisted splints. Their details are given in Table 10 . All these patients were ambulant and 4 had normal use of the noninvolved hand. The brachial plexus lesions fitted with splints in the year prior to this survey are still using the appliance.
Details are available on 9 of the 12 patients who were fitted with gas-powered splints (Table 11 ). Of these, 5 were high cervical cord lesions. Two patients regained sufficient strength in the hands to discard the splints. Three patients discarded the splint because they could not put it on and take it off themselves ; 2 of these have learnt to write with their pen held in their mouth and one uses a simple cuff splint with attachments for pen, fork, spoon, toothbrush and paintbrush. One tetraplegic patient uses a gas-powered splint "occasionally" for writing and had used it when taking examinations. His main complaint is that he cannot put it on and take it off himself, and this is the factor which prevents him continuing to use it.
Two patients with brachial plexus lesions found that the powered splint in conjunction with the flail arm splint was too cumbersome (Nichols, et al, 1975). One patient has a bilateral congenital abnormality and a low IQ but he wears a gas powered flexor hinge splint continuously; however he is frustrated by repeated breakdowns as the device is not robust enough for the activities which he attempts to achieve.
Bilateral wrist-driven splints
Six patients were issued with bilateral wrist-driven splints (Table 12 ). Three patients found they could only use one splint at a time because the sensory difficulties of tetraplegics necessitates careful vigilance and patients found it difficult to watch both hands at once. One of the three, who uses one splint for 15 hours a day, commented that persistent use of one hand has resulted in gross under-development of the other side of his body. Two of the 6 patients were fitted with a second splint at their own request during the period of the study and are still using both splints; one for his clerical job, and the other patient—a housewife—for certain tasks in the kitchen and for rug-making. The sixth patient used one splint only for eighteen months but then found that the quality of writing ability which the splint provided was inadequate for the demands of his job and further education.
These findings support the views of others (Engel et al, 1967; Sabine et al, 1965), that the advantages of one unsplinted hand outweigh those of the bilateral pinch grip using two splints, except for specific tasks.
For a disabled person dependent for functional activities upon aids or appliances, mechanical reliability and efficient maintenance services are of the utmost importance. In our experience there are two main problems in the maintenance of flexor hinge hand splints, the finger cage tends to get knocked out of alignment during strenuous use and during handling, occasionally a finger cage has been broken off. The moving parts of the splint tend to wear out and this has been a factor which has determined some of the later developments and adaptations to the original design.
As a generalization it is our experience that once fitted and found to be comfortable and satisfactory during the post-fitting training period, the splints are remarkably reliable and robust. Minor repairs and replacements are carried out on a postal basis for all our patients.
It is only when a splint has to be completely renewed or a major adaptation carried out because of altered requirements, changing activities, or altered clinical status, that readmission becomes necessary.
In our survey of 52 patients only 7 recorded serious breakdown of non-powered splints.
Powered splints are a different problem in so much that the connecting tubing and controls of the gas power tend to wear and then they require more frequent maintenance than the non-powered splint, but only one patient recorded breakdown problems.
Independence for application
One major problem which often led to rejection of the splint was the patient's inability to put it on and take it off himself. When another person is necessary to put the appliance on, or to set up the activity for which the device is necessary, acceptance is more dependent upon that person's interest and enthusiasm rather than that of the user. Many patients commented on this difficulty but in our series the analysis of answers did not show a statistically significant difference (Table 13 ).
Self propelling wheelchairs
Another major factor which caused some of our earlier patients to discard the splint were the difficulties experienced in propelling wheelchairs while wearing the splint. The modification from the "palmar" linkage to the "dorsal" linkage, plus the inclusion of a "ratchet" has eased this problem but it still remains a difficulty for some.
It is part of our rehabilitation philosophy to actively encourage severely disabled people to take up specific non-vocational activity (Nichols, 1971) an approach strongly emphasized in relation to the rehabilitation of tetraplegics by Runge (1966).
We are convinced that early fitting of the flexor hinge hand splint is probably the most important factor in achieving long-term acceptance and usage. The splint making programmes are usually closely integrated with the early hospital care, indeed, in some units the splints are routinely fitted while patients are still confined to bed in the early phase of management (Meyer, 1974). In Mary Marlborough Lodge we are only involved in the late rehabilitation of tetraplegics but even so, the acceptance rate is nearly 40 per cent for wrist-driven splints. Of the 23 tetraplegic non-users, 12 were fitted more than three years after the injury whereas only 1 of 14 users was fitted after that length of delay. These figures may not be related solely to the time factor. Other factors, such as length of training period, encouragement of friends and family, and the patient's interest in achieving a specific goal are also involved.
Need for flexor hinge hand splints in the UK Accurate statistics about the incidence of spinal cord lesions in the UK are not readily available. Extrapolating from the figures quoted by Guttman (1973) from the various spinal units in the UK it would appear that about 500-600 new cases are admitted every year. Of these about 100-200 will be tetraplegic. At minimum therefore about 30-60 patients each year are likely to derive considerable functional benefit from a flexor hinge hand splint and a further 30-60 would benefit from reconstructive surgery.
It is often more instructive to analyse our failures than our successes. In general, the immediate acceptance of an aid or orthotic device depends upon the skills of the technician making the device, whether it is comfortable and whether it is aesthetically acceptable. But above all, it probably depends upon the enthusiasm of the therapist for the use of the device and her belief in its therapeutic value or its functional value. In the long term it depends on whether the device enables the patient to achieve some activity which he really wants to do (Table 14 ).
The flexor hinge hand splint has a functional value for a proportion of patients with tetraplegia. In our series 6 patients used their splint for work, 8 used it for toilet activities, and 4 specified that they were unable to manage their own incontinence devices without the aid of the splint. Ten patients write with the aid of the splint and 10 use it for a variety of hobbies and leisure activities. One patient wears the splint all day while at work as a school-teacher, and 1 child was enabled to remain at normal school because of the splint, without it he would have gone to a school for the physically handicapped. Thus, for some patients, the splint becomes an essential key to independence.
The establishment of a number of spinal injury units for the early care and rehabilitation needs of spinal paralysis patients has been proposed (DHSS, 1972).
This paper is in part an appeal for the inclusion of comprehensive rehabilitation facilities with appropriate orthotic skills to be available to such units. It also indicates that such units might benefit from a more comprehensive rehabilitation programme where the skills of orthopaedic surgeons, orthotists and remedial therapists, which have been derived from the care of a variety of different clinical problems, can be harnessed and applied to the needs of the tetraplegic patient.
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