Objectives Spasticity is a velocity dependant increase in muscle tone as the result of upper motor neuron dysfunction and or injury. This increased tone can result in decreased range of motion, discomfort, reduction in hygiene, pressure ulcers, subluxations and infections. Treatments for spasticity are botulinum toxin injections and surgical or chemical neurolysis. Cryoneurolysis in a novel treatment for spasticity that uses cold temperatures (~-60°C) to destroy a peripheral nerve. This is advantageous over established treatments as it keeps the surrounding structures intact allowing for regeneration of the nerve unlike chemical or surgical neurolysis. Additionally, treatment is needed less frequently than botulinum toxin injections lowering overall costs and burden on patients. In this retrospective study, we researched the long term outcomes of cryoneurolysis treatment of spasticity of the ankle joint in 34 patients. Design The Modified Ashworth Scale (MAS) and Modified Tardieu Scale were used to assess ankle dorsiflexion. MAS, V3 and V1 were measured with the knee both extended and flexed. Paired t-tests compared baseline and most recent ROM and MAS scores. Average changes in ROM, MAS, and follow-up time were calculated. Results Average ROM increases were 6.25° ± 2.51 and 7.88°± 2.43, and 3.33° ± 2.61/ 6.54° ± 2.70 for V3 and V1 (flexed/extended), respectively. Average MAS scores decreased -0.83 ± 0.18 (flexed) and -0.66 ± 0.18 (extended) points. All results were found to be significant except for V3 with the knee extended: V3 (knee flexed /extended) p = 0.017, 0.21; V1 (flexed/extended) p = 0.0024, 0.020; MAS (flexed/extended) p = 4.49E-5, 0.00054. Conclusions All but one measures remained significantly improved after 17 following treatment indicating continuing significant increases in range of motion and decrease in spasticity. These results indicate that cryoneurolysis is an effective long-term treatment for spasticity causing decreased ankle dorsiflexion.
Research Study with Best Paper Award Abstract
Introduction:
Spasticity is a velocity dependant increase in muscle tone as the result of upper motor neuron dysfunction and or injury. This increased tone can result in decreased range of motion, discomfort, reduction in hygiene, pressure ulcers, subluxations and infections. All of these can significantly decrease patient quality of life and result in the need for significant care. The most common treatments for spasticity are botulinum toxin injections and surgical or chemical neurolysis. Cryoneurolysis in a novel treatment for spasticity that uses cold temperatures (~-60°C) to destroy a peripheral nerve. Cryoneurolysis treatment keeps the surrounding and supporting structures of the nerve intact which allows for Wallerian regeneration of the nerve. This makes the effects of the treatment reversible. This is advantageous over chemical or surgical neurolysis which destroy the surrounding structures making the effects of the treatment permanent. Additionally, cryoneurolysis treatment is less frequently than botulinum toxin injections. This lowers the overall costs and burden on patients as well as the health care system.
Treatment of spasticity in the ankle joint has clinical significance. Improved ankle mobility in patients who experienced stroke has been shown to improve balance and gait ability. Improved gait can increase a patient’s ability to perform activities of daily living and decrease need for support.
Objectives:
In this research study we investigated the treatment of spasticity of the ankle joint using cryoneurolysis. We looked at the long-term effects on patient’s passive ankle mobility and spasticity measures in patients receiving cryoneurolysis to the lower limb.
Methods:
This investigation was conducted as a retrospective chart review. Institutional ethics approval was obtained from the local Research Ethics Board under the protocol number [H23-00533]. In accordance with institutional and national guidelines for retrospective studies involving minimal risk, a waiver of informed consent was approved due to the use of anonymized patient data.
The patients included in this study has previously been enrolled in an earlier investigation in which follow up was limited to one year. In present study, we reviewed their medical records to assess outcomes beyond the one-year time point.
34 patients were enrolled in this study. The diagnoses of the patients include CVA (N=17), MS (N=10), CP (N=4), SCI (N=1), spastic paraparesis (N=1) and myelopathy secondary to HIV (N=1). Six patients had bilateral treatment 34 received unilateral treatment. Measurements from bilaterally treated patients were treated as independent patients. Patients in the previous study were treated once and followed up with after one year. This study follows the same patients after one year until their next treatment or last follow up appointment. The Modified Ashworth Scale (MAS) and Modified Tardieu Scale were used as measures of Spasticity and range of motion in the ankle joint respectively. MAS, V3 and V1 were measured with the knee both extended and flexed. Paired t-tests were used to compare baseline and most recent ROM and MAS scores. Average changes in ROM, MAS, and follow-up time were calculated. A p value of 0.05 was used as the standard of significance. N=40 for all groups except V3 and V1 with the knee extended. In these groups N = 39 due to missing data from one patient with CVA.
Results:
Average ROM increases were 6.25° ± 2.51 and 7.88°± 2.43, and 3.33° ± 2.61/ 6.54° ± 2.70 for V3 and V1 (flexed/extended), respectively. Average MAS scores decreased -0.83 ± 0.18 (flexed) and -0.66 ± 0.18 (extended) points. All results were found to be significant except for V3 with the knee extended: V3 (knee flexed /extended) p = 0.017, 0.21; V1 (flexed/extended) p = 0.0024, 0.020; MAS (flexed/extended) p = 4.49E-5, 0.00054. Mean follow-up time ranged from 16.99 to 17.12 months across measures.
Discussion:
All the measures were significantly improved with treatment indicating significant increases in range of motion and decrease in spasticity except for V3 with the knee extended. Additionally, the average follow up period was ~17 months indicating that cryoneurolysis is an effective long-term treatment for spasticity causing decreased ankle dorsiflexion.
These results indicate that cryoneurolysis is an effective long term treatment option for patients experiencing spasticity affecting ankle dorsiflexion. The mean improvement in range of motion from 6-8 degrees is clinically significant as small improvements in ROM of the ankle can result in large increases in functionality and improved gait. The improved ROM with the knee extended and flexed indicates that cryoneurolysis is effective at treating spasticity in the gastrocnemius and soleus respectively. Improvements in V3 and V1 indicate that cryoneurolysis is effective at treating both the velocity dependant spastic catch and passive muscle tightness.
Additionally, a mean final follows up of ~17 months shows how cryoneurolysis can be used long term to maintain the improvements gained from the treatment. This study represents some of the longest outcome data for the treatment of spasticity using cryoneurolysis.
There are several limitations to this study. This study does not have a control group. Because this is a retrospective study there is potential for bias in the results. Additionally, this study did not control for the diagnosis and severity of the patients which may confound the results. Functional outcomes such as gait speed, and balance were not collected so the connection between functional gain and the cryoneurolysis is unclear. Also, the results were not compared with treatment alternatives such as botulinum toxin and chemical or surgical neurolysis. Future randomized control trials should directly compare treatment with cryoneurolysis and traditional spasticity treatments, measure functional outcomes to better assess improvements in patient quality of life and functionality and should reinvestigate the long-term effects of the treatment on V3 with the knee extended to determine whether this insignificant result was due to random error.
Conclusion:
Treatment of spasticity of that ankle plantar flexors with cryoneurolysis significantly improved measures of ankle ROM and spasticity. These improvements were maintained for an average of 17 months with as needed treatment. These finding support the use of cryoneurolysis as a long-term treatment option as an alternative to traditional treatments such as botulinum toxin and chemical or surgical neurolysis.
