Peripheral nerve regeneration: A comparative study of the effects of autologous bone marrow-derived mesenchymal stem cells, platelet-rich plasma, and lateral saphenous vein graft as a conduit in a dog model.

BACKGROUND: The quality of healing of peripheral nerve injuries remains a common challenge causing pain and poor quality of life for millions of people and animals annually. AIMS: The objectives of this study were to evaluate the healing quality of facial nerve injury in a dog model following local treatment using an autologous injection of platelet-rich plasma (PRP) or bone marrow-derived mesenchymal stem cells (BM-MSCs) at the injury site in combination with the application of an autologous saphenous vein graft as a conduit. METHODS: 20 apparently healthy adult Mongrel dogs were randomly divided into 4 equal groups. Dogs in groups 1, 2, and 3 were subjected to facial nerve neurectomy and saphenous vein conduit graft implantation at the site of facial nerve injury. Dogs in groups 2 and 3 received 1 ml of autologous PRP and BM-MSCs, respectively. Injections were administered directly in the vein conduit immediately after nerve injury. Dogs in group 1 (grafted but not treated; control) received only an autologous vein graft, and those in group 4 (normal control) received no graft and no PRP or BM-MSCs treatment. The dogs were monitored daily for 8 weeks after surgery. Clinical evaluation of the facial nerve, including lower eyelid, ear drooping, upper lip, and tongue functions, was carried out once per week using a numerical scoring system of 0-3. At the end of the study period (week 8), the facial nerve injury site was evaluated grossly for the presence of adhesions using a numerical scoring system of 0-3. The facial nerve injury site was histopathologically assessed for the existence of perivascular mononuclear cell infiltration, fibrous tissue deposition, and axonal injury using H&E-stained tissue sections. RESULTS: Clinically, BM-MSCs treated dogs experienced significant (p < 0.05) improvement in the lower eyelid, ear, lip, and tongue functions 4 weeks postoperatively compared to other groups. Grossly, the facial nerve graft site in the BM-MSCs treated group showed significantly (p < 0.05) lesser adhesion scores than the other groups. Histopathologically, there was significantly (p < 0.05) less perivascular mononuclear cell infiltration, less collagen deposition, and more normal axons at the facial nerve injury site in the BM-MSCs treated group compared to the other groups. CONCLUSION: This study showed clinically significant enhancement of nerve regeneration by applying autologous BM-MSCs and autologous vein grafting at the site of facial nerve injury. However, further clinical trials are warranted before this application can be recommended to treat traumatic nerve injuries in the field.

Facial nerve paralysis in 64 equids: Clinical variables, diagnosis, and outcome.

BACKGROUND: Facial nerve paralysis (FNP) in equids is not well described in the veterinary literature. OBJECTIVE: To investigate the causes of FNP and associations among clinical variables, diagnosis, and outcome. ANIMALS: Sixty-four equids presenting with FNP between July 2000 and April 2019. Cases of postanesthetic FNP were excluded. METHODS: Medical records were retrospectively reviewed. Variables were evaluated for associations with outcomes (diagnosis and case outcome) using logistic regression. RESULTS: The most common cause of FNP was trauma (n = 20). Additional diagnoses included central nervous system (CNS) disease (n = 16), idiopathic (n = 12, 4 of which had adequate diagnostic investigation and were considered "true" idiopathic, and 8 of which were considered "not investigated" idiopathic), temporohyoid osteoarthropathy (n = 10), otitis media-interna (n = 3), lymphoma (n = 1), iatrogenic as a consequence of infiltration of local anesthetic (n = 1), and clostridial myositis (n = 1). Follow-up was available for 55 (86%) cases. Twenty-nine (53%) equids had full resolution of FNP, 14 (25%) were euthanized, 6 (11%) partially improved, and 6 (11%) were unchanged or worse. CONCLUSIONS AND CLINICAL IMPORTANCE: If FNP is the consequence of CNS disease, successful treatment of the primary disease likely leads to resolution of FNP. Most cases of FNP in equids are traumatic in origin. True idiopathic cases are uncommon.

Epineurial repair of an iatrogenic facial nerve neurotmesis after total ear canal ablation and lateral bulla osteotomy in a dog with concurrent cranio-mandibular osteopathy.

A 7-year-old male entire West Highland white terrier was referred to the Small Animal Hospital at the University of Glasgow for bilateral, chronic, medically unresponsive otitis media and externa. A history of cranio-mandibular osteopathy was also reported. Bilateral total ear canal ablation and lateral bulla osteotomy was performed with the aid of a pneumatic burr. Extensive bone proliferation was present bilaterally originating from the caudal mandibular ramus and tympanic bulla which incorporated the horizontal canal on each side. The right facial nerve was identified leaving the stylomastoid foramen and running in a cranial direction through a 1.5 cm diameter cuff of bone surrounding the horizontal canal and external acoustic meatus. Despite careful dissection, a facial nerve neurotmesis ensued which required microsurgical epineurial repair. Neurologic examination performed 12 h post-operatively revealed abnormalities consistent with right facial nerve paralysis. At 3 months, the facial nerve function was found to have improved significantly and was assessed to be normal four months after surgery. To the authors' knowledge, this clinical communication described the first reported clinical case where unilateral facial nerve paralysis resulting from iatrogenic facial nerve neurotmesis was successfully treated by microsurgical epineurial repair.

Surgical management of acute ear canal separation in a cat.

A 5-year-old cat presented with haemorrhagic left aural discharge, 2 days following a road traffic accident. Otoscopic examination identified disruption of the external ear canal at the auricular/annular cartilage junction. This was managed by total ear canal ablation and lateral bulla osteotomy. Left sided facial nerve deficits were present following surgery. Eighteen months postoperatively there were no auricular problems, however facial nerve deficits persisted. There are no previous reports describing management of acute separation at the auricular/annular cartilage junction of the external ear in the cat or dog. This case report describes the presentation, diagnosis and surgical management of an acute ear canal separation at the auricular/annular junction of the external ear canal in a cat.