A V-OP patient evaluation must be thorough enough to provide a specific device prescription. It must take into account the entire patient from a mechanical and physiological perspective in addition to a clear understanding of the primary injury. The V-OP examination must fully define the presenting deficit, characterize biomechanical implications, identify complicators or comorbidities, and diagnose all primary and secondary pain generators. The examination should include a general wellness assessment in addition to orthopedic, myofascial, biomechanical, and neurologic examinations. Additionally, the case must be understood from the standpoint of lifestyle, environment, family dynamics, sport or activity, goals and intended outcome as defined by client and veterinarian, and alignment of goals with proposed orthotic or prosthetic device. The good news is that with the help of a qualified fabricator as noted previously, the general practitioner can succeed in providing V-OP devices.
Once a plan is developed and the device is designed, the next step in creating a custom orthosis or prosthesis is fiberglass impression molding of the limb. This step is critical for optimal fit and correct function of the device. Creating a precise replica of the limb in a thin layer of fiberglass tape requires a bit of artistic acumen and a clear sense of device purpose. This fiberglass impression is used to create a plaster model from which the custom device will be fabricated. Therefore, the limb must be molded in the properly aligned position. Just as a poorly positioned or exposed radiograph is less than adequate for accurate diagnosis, a poorly molded fiberglass impression is equally useless in fabricating the best device.
Manufacturing requires skilled modification of the model by hand or using computer-assisted design to build reliefs, which accommodate limb topography and create appropriate corrective forces when the completed device is applied to the limb. The modified model is the structure on which a thermoplastic shell is vacuum formed. The shell is then hand cut, trimmed, and ground to the final shape. Materials used to pad and line the shell vary. Hinges, straps, pads, and motion-limiting components complete fabrication. The typical custom V-OP device cost varies with components and materials and averages $600-$1000. This does not include the necessary appointments to ensure proper fit and function along with client education.
An important advantage to veterinarian-guided use of a V-OP device is fit and function assessment and adjustment. Adjustments are expected and are a normal part of the custom process. Reputable custom fabricators strive to accurately fit the device; however, variations in injury severity, gaiting pattern, and level and intensity of activity all affect the accuracy of initial fit and cannot be predicted in all cases. Couple this with a dynamic process such as Achilles tendon therapy and the necessity for adjustability is clear. Pressure and friction irritation are the most common reasons for adjustment followed by the natural progression of the case. Fortunately, with a removable device, such issues are quickly recognized and corrected; this is an advantage over casts and splints that are changed weekly at best.
Orthoses and prostheses are considered “durable medical devices.” This means that proper use is necessary to meet therapeutic goals and to ensure safe application over the lifetime of the patient or the duration of injury healing. Typically, several follow-up assessments are advised in the first few months. Thereafter, annual to twice-annual appointments, depending on injury, age, and activity of the patient, are needed. At these appointments, the orthopedic condition of the patient and the condition or fit of the device should be evaluated. Lastly, short- and long-term plans are adjusted.