The ROM Splint
Inventor: Brandon Davies-Sekle - LinkedIn
About the ROM Splint
The ROM (Range of Motion) Splint is a project aimed at creating a series of dynamic splints to aid primarily people with brachial plexus injuries in rehabilitating and adapting to them.
After four years of development this project is in the stage of seeking a licenser to:
manufacture and distribute customized ROM splints to end users
obtain any approvals, including FDA, needed to legally manufacture and distribute them in the US and internationally
optimize the design to make it ideal from a usability and manufacturing standpoint, incorporating any additional improvements needed for it to reach its full potential
continue research and development on each version of the device to improve the series over time. Potentially create myoelectric versions
The basis of the design is a fully mechanical splint that, while worn, permits the affected arm to move throughout its normal rotational DOF (Degrees of Freedom), can lock certain DOF at user-selected angles, and can control the rotation of these DOF.
Overall, the series is designed to help three groups of people:
(1) people with brachial plexus damage that has resulted in some degree of paralysis and decreased range of motion
(2) people with a non-neurological injury to the arm or shoulder and
(3) those that want to target certain muscles of the arm and shoulder within their workouts.
Brachial plexus injuries commonly occur due to birth-related trauma, accidents such as motorcycle, or stroke. Currently, surgical intervention can help a great deal but is not usually enough to completely restore function. To learn more about brachial plexus injuries visit this page on the Mayo Clinic website.
For people in groups (1) or (2), the ROM splint aims to help stretch the arm and complete certain rehabilitative exercises that would otherwise be difficult or ineffective. It accomplishes this firstly by allowing the user to lock the arm in selected positions for prolonged stretching. Secondly, with appropriate DOF being free and others locked at selected angles of rotation, the splint restricts the use of the stronger muscles in the arm that would otherwise compensate for the weaker ones and prevent them from getting sufficiently exercised, so that the mental effort used to perform an exercise during resistance training forces the weaker muscles (weaker due to damaged nerves or general injury) to be the primary provider of the motion.
Before rehabilitation has been reached or when the capacity for rehabilitation has been maximized and recovery is less than 100%, the ROM splint also helps people in groups (1) or (2) adapt to performing certain movements. With appropriate DOF being free and others being locked at selected angles of rotation, the splint helps the wearer supplement motions they don't have the ability to perform in order to maximize the ones they do. With the range being limited, it is only possible to move the arm in the planes desired. People in group (3) may not necessarily be injured but may benefit from the splint’s ability to stretch and from its potential to serve as a workout tool that allows certain primary muscles to be targeted without interaction from secondary muscles. Examples of movements, exercises, and adaptations are provided in the Animations section of the ROM4 model page.
Use of the splint can provide several benefits but they are limited by the extent of any injuries. In general, for people in groups (1) or (2), it can increase the strength and size of the muscles, decrease nerve pain, and improve motor function. After using it to assist with stretching and resistance training, the improved condition of the arm makes it easier to complete everyday tasks, such as washing dishes, and recreational tasks, such as certain movements required for sports. It can also improve the ability of users to do more motor-related tasks, such as typing or playing a musical instrument. Aside from serving as a device that helps adapt, it can also serve as a support device where simply being able to lock the arm in certain positions may allow certain tasks to be completed or may provide a level of comfort. For example, by locking the shoulder at the splint’s max internal rotation angle, locking the elbow at 90 degrees, and locking the other axes appropriately, it can be worn like a traditional sling.
Different models within the ROM splint series are governed by the DOFs that are permissible, controllable, and lockable.
The ROM2 Splint
About the ROM2 Splint
The ROM2 splint is the first prototyped model of The ROM Splint series and was designed before the concept currently being used to control and lock the DOF (Degrees of Freedom) was realized. It is a dynamic 3-axis range of motion splint that allows the forearm to be locked at any angle of pronation or supination, the shoulder to be locked at incremental angles of internal or external rotation, and the elbow’s flexion and extension to be limited or locked at incremental angles. The number "2" represents the number of primary axes that can be controlled. For the shoulder's internal or external rotation and the elbow's flexion or extension, the splint allows the user to switch back and forth between a state of being locked and a state of being free to move throughout its normal range. This means that, when in the free state, these DOF can be moved through as though the splint wasn’t being worn. The forearm cannot be freed to move in its rotation but can only be locked at the angle selected.
The splint’s mechanical components are all attached to a flexible shoulder brace. By itself, the shoulder brace serves its traditional purpose, which is to alleviate pain and discomfort to the shoulder area by providing support to the rotator cuff. Possible causes of such pain and discomfort include but are not limited to sprains, tendonitis, arthritis, and subluxations.
More information on the ROM2 and its assemblies and components can be found here.
The ROM4 Splint
About the ROM4 Splint
The ROM4 is the second model of the ROM splint series. It is a dynamic 6-axis range of motion splint that allows "4" primary axes to be controlled. After completing the ROM2, a number of improvements were required to realize the ideal concept of being able to move the affected arm throughout all of its normal rotational DOF (Degrees of Freedom), to control these movements when desired, and to lock the DOF at selected angles. In addition, the aim was to make the splint more effective, versatile, robust, and easy-to-use.
These improvements were realized through the ROM4 and include:
The switch from a shoulder brace to a torso vest as the main point of attachment for the components that comprise the splint. The torso vest is much more rigidly attached to the torso than the shoulder brace, so it allows components to be anchored off of it as though they were attached directly to the torso
The addition of shoulder flexion-extension and shoulder adduction-abduction to the permissible and controllable axes of rotation
The switch from only allowing discrete angles of internal-external rotation to be selected to allowing any angle to be selected
The addition of a clutch system to be able to switch each rotation axis between a state of being locked and a state of being free to move under the power of the wearer
The addition of the ability to permit and lock the motion of the scapula
The addition of a wrist cuff assembly that clamps to the wrist and forearm using a ratchet locking system. This makes clamping the assembly much quicker and easier than the versions that use straps or thumbscrews to initiate the clamping
The vision is that each future splint within the series would be built based on this general model by configuring what DOF are permissible and whether or not they can be controlled and locked. Additional customization would be incorporated to suit the needs of each individual.
More information on the ROM4 and its assemblies and components can be found here.
The Need for the Invention
Impetus for Creation
Partial paralysis or nerve impairments to the muscles in the arm and shoulder (controlled by the brachial plexus) can be caused by a number of factors, such as injury or stroke, and may be diagnosed as a palsy, such as Erb’s. This is typically accompanied by some degree of atrophy and weakness in the effected muscles, a limited range of motion (with or without muscular control), and diminished motor skills, especially when nerve impairments result in tremors. The arm and shoulder have seven primary rotational DOF (Degrees of Freedom) which may become limited, including shoulder internal/external rotation, shoulder abduction/adduction, shoulder flexion/extension, elbow flexion/extension, forearm pronation/supination, wrist flexion/extension, and wrist ulnar/radial deviation. In addition, the motions of the scapula may become impaired.
Apart from surgical intervention, it is common to try to improve the condition using physical therapy (possibly orchestrated by a physical or occupational therapist) or some form of resistance training. Such resistance training often involves the use of traditional equipment, such as resistance bands, cables, dumbbells, and medicine balls, where an attempt is made to modify the exercises, from those which would be used on an undamaged arm, to make them more effective at rehabilitating the condition.
Unfortunately, current physical therapy and resistance training techniques alone are generally limited in their capacity to provide the greatest possible recuperation of muscular strength and range of motion. This is due to it being extremely difficult near impossible to achieve the mechanics of the necessary exercise movements to stop the stronger muscles of the arm and shoulder from compensating for the weaker ones. In this instance, the stronger muscles do the majority of the work that creates the motion, and the weaker ones, not being in an appropriate anatomical configuration, do not receive enough stimulation to realize a significant amount of recovery. Additionally, attempts at putting the arm in such anatomical positions using traditional equipment may put more resistance on the arm than it is presently capable of moving, instead of putting the arm in positions where the resistance created by the weight of the arm itself can be started with before adding any weight beyond that. Furthermore, even when the weaker muscles are put in a position where they’re forced to do the majority of the work, strength may be lacked to execute any movement.
The ineffectiveness is also due to the inability to provide a prolonged stretch to the necessary muscles of the arm and shoulder when needed.
The appropriate anatomical configurations and prolonged stretching could be achieved by an orthosis (splint) that provides control over one or more of the seven rotational DOF, addressing the range of motion of the arm and shoulder. For each DOF, the orthosis could do this by providing a mechanical means of restricting the rotational range of the motion, by allowing certain angular positions to be locked, and by allowing the motion to be switched back and forth between a state of being locked and a state of being free to move within the restricted range.
The direct stimulation and stretching provided to the affected muscles could possibly instigate hypertrophy, elongation, and nerve recovery that would lead to the greatest possible rehabilitation. The use of the word “dynamic” regarding such an orthosis refers to its capacity to allow the arm and shoulder to move around within the DOF and to its capacity to select different lockable positions. Additionally, it means that the bulk of the recovery to impaired muscles is achieved through motion rather than statically. The ideal such orthosis has several characteristics. Firstly, it leaves the hand on the effected arm free so that exercise equipment may be grasped. Secondly, it can be put on and taken off without assistance if the user has another sufficiently functioning arm. Thirdly, it can be adjusted with one hand. And lastly, it is not excessively cumbersome or heavy so that it’s comfortable enough to be worn all the time or when needed. A need, therefore, has developed for an orthotic device that provides an adjustable amount of forced motion to some or all of the arm and shoulder's DOF and that can switch each DOF between a state of being locked and a state of being free. The ROM splint was invented to address that need.
Possible future work includes streamlining the ROM splint for weight reduction, reducing friction between sliding components, and implementing variable clutches that can engage at any angle. There is great interest, as well, in creating a myoelectric version with the ROM splint serving as the skeleton. This would provide whole-arm control but mechanisms would have to be incorporated to control the hand and fingers. Another possible future work is the idea of applying external forces to the arm and shoulder using soft robotics.