Does cryoneurolysis result in persistent motor deficits? A controlled study using a rat peroneal nerve injury model

Abstract

BackgroundCryoneurolysis of peripheral nerves uses localised intense cold to induce a prolonged block over multiple weeks that has the promise of providing potent analgesia outlasting the duration of postoperative pain following surgery, as well as treat other acute and chronic pain states. However, it remains unclear whether persistent functional motor deficits remain following cryoneurolysis of mixed sensorimotor peripheral nerves, greatly limiting clinical application of this modality. To help inform future research, we used a rat peroneal nerve injury model to evaluate if cryoneurolysis results in persistent deficits in motor function.MethodsMale Lewis rats (n=30) had their common peroneal nerves exposed bilaterally at the proximal lateral margin of the knee and subsequently underwent cryoneurolysis on one limb and sham treatment on the contralateral limb. Outcomes were evaluated on days 3, 14, 30, 90 and 180. The primary end point was motor function, based on ankle dorsiflexion torque. In addition, sensory function was tested based on von Frey’s filament sensitivity to the peroneal sensory distribution. A subset of animals was sacrificed following functional testing at each time point, and general tissue morphology, connective tissue deposition, and axon counts were evaluated.ResultsMotor deficits in treated limbs were observed at 3 and 14 days but had resolved at time points beyond 1 month. Bilateral sensory deficits were also observed at 3 and 14 days, and also resolved within 1 month. Consistent with motor functional deficits, axon counts trended lower in treated nerves compared with contralateral controls at 3 days; however, axon counts were not significantly different at later time points.ConclusionsWhen applied to a mixed sensorimotor nerve, cryoneurolysis did not result in persistent motor deficits.

Cryoneurolysis and Percutaneous Peripheral Nerve Stimulation to Treat Acute Pain

“…100 Importantly, treatment with 10% procaine HCl to intercostal nerves within the same animal study resulted in similar deficit and recovery patterns. 100 In contrast, three preclinical studies designed specifically to address this issue revealed no long-term changes to the structure or function of mixed nerves and their motor targets after tibial or common peroneal nerve cryoneurolysis and subsequent axonal regeneration and remyelination 99,101,102 -even with repeated applications. 101…”

“…11 However, various investigators have suggested the possibility of subclinical residual and persistent motor weakness caused by either incomplete regeneration or motor unit clustering. 99 There are preclinical data from laboratory animals suggesting decreased nerve conduction velocities 90 days after cryoneurolysis of intercostal nerves, but all physiologic and behavioral measures fully returned to normal by that time point (subsequent time points were not evaluated). 100 Importantly, treatment with 10% procaine HCl to intercostal nerves within the same animal study resulted in similar deficit and recovery patterns.…”

Ultrasound-Guided Percutaneous Cryoanalgesia for Pectus Excavatum: When Should It be Applied?

“…The complications described are minimal (local hematomas), there is no evidence of permanent nerve damage or neuroma, and only one serious case of myonecrosis and abscess has been described. 15,[23][24][25][26][27][28] In our series, there were no serious complications related to the technique. Nausea and vomiting were present in 95.8% of patients and most related it to opioid use.…”

Development of a common peroneal nerve injury model in domestic swine for the study of translational neuropathic pain treatments

“…Rodent CPNI models based on VFF responses have shown that nerve ligation results in 180 days of neuropathic allodynia. 39 Threshold responses remain analogous between time points 7 days and 6 months after surgery. Similar effects have been found in peripheral nerve injury models in large animals.…”