Case Study: Physical Rehabilitation
Saturday, April 24, 2021 at 01:00PM
Introduction
Cervical vertebrae one and two (atlas and axis, respectively) play a crucial role in normal movement of the head through a pivoting motion of C1 around the dens of C2. The intervertebral joint space lacks an intervertebral disc and the integrity of the joint is largely maintained by ligaments.1 Toy breed dogs are predisposed to instability of this joint2 and are likely to develop clinical signs consistent with neurologic deficit following trauma to a congenital lesion. The patient in this study was diagnosed with atlantoaxial subluxation and fracture of the dens following an acute trauma. The patient was immediately taken to surgery where a ventral slot was performed to stabilize the fracture, and multimodal postoperative pain management and rehabilitation were instituted to improve prognosis. Following three months of home exercise and weekly rehabilitation sessions, the patient has regained his ability to perform normal daily living activities and his guardians report they are very pleased with the outcome, especially given the initial guarded prognosis.
Clinical Findings/Assessment
An 8 month old intact male Miniature Schnauzer presented to the VMCVM’s neurology department for an emergent episode of collapse and respiratory distress with cyanotic mucous membranes and hypoventilation. Neurologic examination revealed non-ambulatory tetraplegia, depressed mentation, and postural reaction deficits absent in all four limbs with cranial nerves within normal limits. The patient had presented to the referring veterinarian one month prior for neck pain and weakness after playing with a housemate. The pain was initially treated with oral medications and clinical signs seemed to resolve until one week prior to the current presentation. MRI and CT scan of the cervical vertebrae were performed under anesthesia and revealed extradural spinal cord compression secondary to atlantoaxial subluxation and dens fracture with associated local spinal cord contusion and multifocal cervical intervertebral disc degeneration. It was determined that the dens had congenital malformation.
Treatments/Modalities
The patient was immediately stabilized and transferred to surgery for C1-2 ventral stabilization. Following an uncomplicated surgery the patient was given an injection of methadone, but additional pharmaceuticals were not administered in order to reduce cardiopulmonary effects in light of the continued hypoventilation. The incision site was treated using an ice pack immediately postoperatively because cryotherapy has been shown to modulate the TRPM8 sensory receptor to result in increased thermal and mechanical pain thresholds related to neuropathic injury. 3 Oxygen was delivered at 40% FiO2 overnight via oxygen cage until the patient’s mentation improved and breathing began to normalize. At this time, the patient was started on a Ketamine CRI at 2mcg/kg/min, and given an antiinflammatory dose of Dexamethasone SP for any potential swelling in the cervical region that may affect pain and breathing. Ketamine is an NMDA receptor antagonist chosen for this patient for its anti-hyperalgesic and anti-allodynic effect. Numerous studies have shown the opioid sparing effect of Ketamine, in addition to its ability to mitigate chronic pain states from developing following surgery. 4,5 Arterial blood gasses continued to show low oxygen concentration (pO2 72, normal range 81-1036), so the patient was kept on oxygen support and slowly weaned off of oxygen therapy over several days. The ketamine CRI was slowly weaned over 3 days and oral gabapentin was started at 30 mg three times daily. Gabapentin has been shown in humans to reduce neuropathic pain and has FDA approval for certain conditions, but studies showing veterinary efficacy are currently lacking. Nonetheless, clinical use of gabapentin is common and appears to improve patient quality of life.7 Antiinflammatory doses of oral prednisolone were also started by mouth once daily and passive range of motion (PROM) was ordered for every eight hours. PROM is recommended for all patients in situations where loss of motion is anticipated, including skeletally immature dogs, after severe tissue trauma, and in patients without active limb use, to maintain integrity of the joints and improve overall prognosis.8 After five days in the ICU the patient was discharged and referred for a consultation with the VMCVM’s rehabilitation department.
Due to the age of this patient modalities such as low level laser therapy and therapeutic ultrasound were contraindicated. Photobiomodulation using an 830 nm gallium-aluminum- arsenic diode laser at 5 and 15 J per square centimeter has been shown to cause histologic changes in epiphyseal cartilage of rats9. This finding has been extrapolated to canines because studies in other species are currently lacking. In addition, long term studies have not been conducted so there is no evidence that these changes will not cause lasting effects. Similarly, therapeutic ultrasound has been shown to exert effects on cartilage proliferation in fetal mice10, with long term studies lacking to identify long term effects. Instead of these modalities, the treatment focus for this patient was therapeutic exercise, with the short term goal of regaining motor function in all four limbs, and the long term goal of being able to perform basic activities of daily living for a good quality of life. Studies have reported that body weight exercise training does have a positive effect on locomotor recovery following spinal cord injury in animals, and those with contusions have a better outcome, based on severity of trauma, if treatment is started within two weeks of injury and continued for at least eight weeks.11 Initial therapy prescribed included passive range of motion (PROM), assisted standing and sitting, sphinx pose, gait patterning, and weight shifting two to four times per day as the guardian’s schedule would allow. During inhouse therapy sessions massage (effleurage and petrissage) was combined with PROM to reduce anxiety, break up adhesions, encourage drainage of swelling to lymph tissue, prevent joint capsule rigidity, create movement of synovial fluid for nourishment, and trigger sensation in sensory nerve fibers within the joint. Massage techniques have proven to be useful in improving local circulation for quicker resolution of edema as well as reducing anxiety postoperatively that can contribute to slower healing.12 Using the Canine Manual Muscle Testing (cMMT), scale this patient’s strength was determined to be less than three out of five so exercises were prescribed in an appropriate sequence to help the patient support his own body weight without compensation. Assisted standing/sitting and the sphinx pose used isometric contractions to build strength while weight shifting was added for motor signaling and muscle memory development. As the patient progressed through the program, with weekly visits to in house therapy and daily exercising at home, the exercises were gradually progressed using the overload principle. After eight weeks of treatment the patient was performing sit to stands with a tummy tuck, figure eights, limbo movements, step series using foam pads of different heights, wide circles over low cavaletti poles, and up/downs utilizing a disc.
Outcomes/Results
At his ten week neurology recheck the patient was observed to be ambulatory with improved tetraparesis and ataxia, have return of postural reactions in three of four limbs, have return of withdrawal in all four limbs, and have no sign of hyperpathia. The patient’s guardian reported that he is doing very well at home and she is thrilled with his progress. She is dedicated to continuing his home exercise program and rechecks with the rehabilitation department. Goniometric measurements of all four limbs (Table 1) showed improvement of mass and symmetry and reassessment of the cMMT showed that the patient reached a score of three out of five on both pelvic limbs. The patient does resist ventral flexion of his cervical spine and he maintains a minimal left head tilt, but overall he has responded very well to physical rehabilitation.
Table 1
Muscle Girth (cm) at 3.3 cm distance Before vs After
Right forelimb 7.5 8.5
Left forelimb 7.25 8.5
Right hind 11.25 13
Left hindlimb 11.5 12.5
Summary
Physical rehabilitation truly makes a difference in the recovery and quality of life in veterinary patients. Although this patient may never regain full, normal function due to his spinal cord trauma he is able to sufficiently perform activities of daily living and has a chance to live a full life. This case highlights the importance of the patient-client-therapist team in the success of treatment and showcases how effective physical rehabilitation can be even without added modalities. Many practices lack therapeutic modalities because of financial or spacial issues so it is important for practitioners to realize that manual therapies, even when utilized as sole therapy, are instrumental in providing better care and more effective treatment to rehabilitation patients.
References:
1. Sharp NJH, Wheeler SJ, Trumpey JE. Atlantoaxial subluxation. In: Small animal spinal disorders: diagnosis and surgery. Edinburgh: Elsevier/Mosby; 2007. p. 160–80.
2. Slanina MC. Atlantoaxial Instability. Vet Clin North Am Small Anim Pract. 2016 Mar;46(2):265-75. doi: 10.1016/j.cvsm.2015.10.005. Epub 2015 Nov 27. PMID: 26631590.
3. Knowlton WM, McKemy DD. TRPM8: From Cold to Cancer, Peppermint to Pain. Current Pharmaceutical Biotechnology. 2011;12:68–77.
4. Epstein ME. Subanesthetic Ketamine CRI and Systemic Lidocaine. Lecture presented at: IVAPM Pain Management Core Review 2020;
5. Wagner AE, Walton JA, Hellyer PW, Gaynor JS, Mama KR. Use of low doses of ketamine administered by constant rate infusion as an adjunct for postoperative analgesia in dogs. J Am Vet Med Assoc. 2002 Jul 1;221(1):72-5. doi: 10.2460/javma.2002.221.72. PMID: 12420827.
6. Humm K. How to Interpret Arterial Blood Gas [Internet]. Reading presented at: WSAVA/FECAVA/BSAVA World Congress 2012; [cited 2020Aug10]. Available from: https://www.vin.com/apputil/content/defaultadv1.aspx?id=5328302&pid=11349&print=1
7. Moore SA. Managing Neuropathic Pain in Dogs. Frontiers in Veterinary Science. 2016Feb22.
8. Marcellin-Little DJ, Levine D. Principles and Application of Range of Motion and Stretching in Companion Animals. Veterinary Clinics of North America: Small Animal Practice. 2015Jan;45(1):57–72.
9. Cressoni MD, Giusti HH, Pião AC, de Paiva Carvalho RL, Anaruma CA, Casarotto RA. Effect of GaAlAs laser irradiation on the epiphyseal cartilage of rats. Photomed Laser Surg. 2010 Aug;28(4):527-32. doi: 10.1089/pho.2009.2572. PMID: 20201664.
10. Wiltink A, Nijweide PJ, Oosterbaan WA, Hekkenberg RT, Helders PJ. Effect of therapeutic ultrasound on endochondral ossification. Ultrasound Med Biol. 1995;21(1):121-7. doi: 10.1016/0301-5629(94)00092-1. PMID: 7754572.
11. Battistuzzo CR, Callister RJ, Callister R, Galea MP. A Systematic Review of Exercise Training To Promote Locomotor Recovery in Animal Models of Spinal Cord Injury. Journal of Neurotrauma. 2012May20;29(8):1600–13.
12. Sims C, Waldron R, Marcellin-Little DJ. Rehabilitation and physical therapy for the neurologic veterinary patient. Vet Clin North Am Small Anim Pract. 2015 Jan;45(1):123-43. doi: 10.1016/j.cvsm.2014.09.007. Epub 2014 Oct 14. PMID: 25440754.
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