Surgical treatment of feline intracranial meningiomas: a retrospective study of 26 cases.

BACKGROUND: Surgical excision is the treatment of choice for feline intracranial meningioma. OBJECTIVES: To report clinical findings, complications, and outcomes following surgery for feline intracranial meningioma. METHODS: Medical records (01/2000-01/2017) of cats that underwent surgical excision of an intracranial meningioma at our institution were reviewed. Patient data included signalment, clinical signs, surgical technique, complications, histopathologic diagnosis, survival time, and owners' answers to a satisfaction questionnaire. Survival was assessed using the Kaplan-Meier method and log-rank test. RESULTS: Twenty-six cats were included in this study. The exact cause of death was known in 17 cases and was not related to meningioma in 9/17 cases. Overall median survival time was 881 days (95% confidence interval 518; 1248). The age of the cat did not influence survival (p = 0.94) or the occurrence of complications (p = 0.051). Complications occurred in 13/24 cats, including dramatic complications in 4/24 cats. Most complications appeared in the first 24 hours post-surgery (12/13). Males had more postoperative complications (p = 0.042), including more seizures (p = 0.016). Cats with cranioplasty had fewer complications (p = 0.021). Clinical recurrence was confirmed in 3 out of 17 cats. Recurrence-free survival time was 826 days. Most owners (12/14) were satisfied with the outcome. CONCLUSIONS: Surgical treatment of intracranial meningioma in cats was associated with a long median survival time but also with a high rate of minor and major postoperative complications, including early postoperative seizures. Cranioplasty may reduce complications. Age at the time of surgery had no effect on outcomes.

Mechanical evaluation of a novel angle-stable interlocking nail in a gap fracture model.

OBJECTIVE: To describe the mechanical characteristics of a novel angle-stable interlocking nail (NAS-ILN) and compare them to those of a locking compression plate (LCP) by using a gap-fracture model. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Synthetic bone models. METHODS: Synthetic bone models simulating a 50 mm diaphyseal comminuted canine tibial fracture were treated with either a novel angle-stable interlocking nail (NAS-ILN) or a locking compression plate (LCP). Maximal axial deformation and load to failure in compression and 4-point bending, as well as maximal angular deformation, slack, and torque to failure in torsion, were statistically compared (P < .05). RESULTS: In compression, the maximal axial deformation was lower for NAS-ILN (0.11 mm ± 0.03) than for LCP (1.10 mm ± 0.22) (P < .0001). The ultimate load to failure was higher for NAS-ILN (803.58 N ± 29.52) than for LCP (328.40 N ± 11.01) (P < .0001). In torsion, the maximal angular deformation did not differ between NAS-ILN (22.79° ± 1.48) and LCP (24.36° ± 1.45) (P = .09). The ultimate torque to failure was higher for NAS-ILN (22.45 Nm ± 0.24) than for LCP (19.10 Nm ± 1.36) (P = .001). No slack was observed with NAS-ILN. In 4-point bending, the maximal axial deformation was lower for NAS-ILN (3.19 mm ± 0.49) than for LCP (4.17 mm ± 0.34) (P = .003). The ultimate bending moment was higher for NAS-ILN (25.73 Nm, IQR [23.54-26.86] Nm) than for LCP (16.29 Nm, IQR [15.66-16.47] Nm) (P = .002). CONCLUSION: The NAS-ILN showed greater stiffness in compression and 4-point bending, and a greater resistance to failure in compression, torsion, and 4-point bending, than LCP. CLINICAL IMPACT: Based on these results, NAS-ILNs could be considered as alternative implants for the stabilization of comminuted fractures.

Transoral ventral tympanic bulla osteotomy in cats: 13 cases (2016-2019).

OBJECTIVE: To analyze the results of transoral ventral bulla osteotomy (TOVBO) in cats. ANIMALS: 13 client-owned cats treated by TOVBO between February 2016 and February 2019. PROCEDURES: Medical records of cats with a diagnosis of middle ear disease (MED) that underwent TOVBO were reviewed. The procedure was similar to the one described for dogs. Short-term follow-up was obtained via clinical examination before discharge and at day 15 postoperatively. Long-term follow-up was performed via telephone interview. RESULTS: 13 cats (age range, 8 months to 12 years) underwent unilateral (n = 10) or bilateral (3) TOVBO (16) for the treatment of tympanic bulla (TB) infection (10), nasopharyngeal inflammatory polyps (5), or bullet retrieval from the TB (1). There were no intraoperative complications. One cat with a poor preoperative status died at postoperative day 3 from pneumonia. Eight cats experienced postoperative complications including head tilt (n = 2), Horner syndrome (3), loss of appetite (2), and temporary blindness (1). Collected samples confirmed the presence of nasopharyngeal inflammatory polyps (5), or otitis media (8). Six months after surgical intervention, 9 cats were free of MED signs. CLINICAL RELEVANCE: This oral approach provided a good access to the TB in all cases. The complications observed after TOVBO were similar to those for VBO. In cats, TOVBO seems to be an acceptable and safe minimally invasive alternative to the other approaches of the TB to address MED.

Risk factors and clinical relevance of positive urine cultures in cats with subcutaneous ureteral bypass.

BACKGROUND: The objective of the study was to report the incidence and risk factors associated with positive urine bacterial cultures as well as long-term outcome in cats with subcutaneous ureteral bypass (SUB) devices. RESULTS: Medical records of cats that underwent SUB device placement were retrospectively reviewed. Signalment of the cat, laterality of the ureteral obstruction, surgery, anesthesia and hospitalization duration, bacterial culture results and follow-up data were retrieved. Thirty-two cats met the inclusion criteria. Four cats (12.5%) had a positive intraoperative culture, with two of them being treated successfully. Ten cats out of 28 (35.7%) were documented with a positive urine culture during follow-up period, with a median time between discharge and identification of the first positive urine culture of 159 days (range 8-703 days). Bacteriuria resolved in 60% of cats (6/10). Escherichia coli was the most common organism, isolated in 4 out of 10 postoperative urine cultures. Overall, subclinical bacteriura was documented for 6 of 32 (18.8%) cats and 5 of 32 (15.6%) cats displayed clinicals signs suggestive of persistent UTI. One cat had subclinical bacteriuria. Three cats died during the follow-up period. There was a significant difference between negative and positive urine bacterial culture groups in median hospitalization duration (5 days versus 6 days, P = 0.022) and in median body condition score (5/9 versus 4/9, P = 0.03). Cats with a longer hospital stay and with a lower body condition score were more likely to have a positive urine culture during follow-up period. CONCLUSIONS: SUB device placement surgery is associated with complications such as chronic bacteriuria. Bacteriuria in our study resolved with appropriate antibiotic treatment in more than half of cats. Risk factors identified for positive urine culture were a longer hospitalization duration and a decreased body condition score.

Prevalence of canine hip dysplasia in 10 breeds in France, a retrospective study of the 1997-2017 radiographic screening period.

Canine hip dysplasia (HD) is a complex developmental disease of the coxo-femoral joint and is one of the most common orthopedic conditions in dogs. Due to the genetic contribution, most of the programs fighting against HD recommend selective breeding that excludes affected dogs. Using the best-scoring dogs for breeding may reduce the prevalence of HD. In France, the phenotypic screening of coxo-femoral joint conformation remains a strategy for breeders to establish selection decisions. The HD prevalence was evaluated in 10 breeds, based on the assessment of 27,710 dogs, during the 1997-2017 screening period, which was divided into 3 homogeneous cohorts for analysis. The global HD prevalence varied widely among breeds from 5% (Siberian Husky) to 51.9% (Cane Corso). It decreased over time in 6 breeds, among which 4 (Cane Corso, Gordon Setter, Rottweiler and White Swiss Shepherd) showed a significant decrease. A statistically significant increase in HD prevalence was noted for the Siberian Husky. Although the efficacy of phenotype-based breeding programs remains controversial, our results are in accordance with several recent studies showing that long-term selection policies are valuable, as they may help decreasing the HD prevalence in some breeds. The complementary use of more recent tools such as estimated breeding values and genomics would probably help breeders achieve more substantive results.

Magnetic resonance imaging of a giant frontal hemorrhagic mucocele with intracranial extension in a cat.

A 6-year-old domestic short-haired cat was presented with an acute onset of right cortical encephalopathy. Magnetic resonance imaging (MRI) performed 4 days after the onset of clinical signs revealed a lesion originating from the right frontal sinus with intracranial extension and compression of the right frontal lobe. The lesion was T1-weighted hypointense and T2-weighted and fluid-attenuated inversion recovery hyperintense. Signal voids within the lesion were observed on T2* images, consistent with hemorrhage. Peripheral ring enhancement was visible on postcontrast sequences. These features were consistent with a giant hemorrhagic mucocele. To the authors' knowledge, this is the first report of MRI characteristics of this lesion in a cat.

Esophageal leiomyoma in a dog causing esophageal distension and treated by transcardial placement of a self-expanding, covered, nitinol esophageal stent.

CASE DESCRIPTION A 10-year-old spayed female Rottweiler was referred for evaluation because of a 2-month history of regurgitation and weight loss, despite no apparent change in appetite. The dog had received antiemetic and antacid treatment, without improvement. CLINICAL FINDINGS Physical examination revealed a low body condition score (2/5), but other findings were unremarkable. Diffuse, global esophageal dilatation was noted on plain thoracic radiographs, and normal motility was confirmed through videofluoroscopic evaluation of swallowing. Transhepatic ultrasonographic and CT examination revealed a circumferential, intraparietal lesion in the distal portion of the esophagus causing distal esophageal or cardial subobstruction and no metastases. Incisional biopsy of the lesion was performed, and findings of histologic examination supported a diagnosis of esophageal leiomyoma. TREATMENT AND OUTCOME In view of numerous possible complications associated with esophageal surgery, the decision was made to palliatively treat the dog by transcardial placement of a self-expanding, covered, nitinol esophageal stent under endoscopic guidance. Two weeks after stent placement, radiography revealed complete migration of the stent into the gastric lumen. Gastrotomy was performed, and the stent was replaced and fixed in place. Twenty-four months after initial stent placement, the dog had a healthy body condition and remained free of previous clinical signs. CLINICAL RELEVANCE Diffuse benign muscular neoplasia should be considered as a differential diagnosis for acquired esophageal dilatation in adult and elderly dogs. In the dog of this report, transcardial stent placement resulted in resolution of the clinical signs, with no apparent adverse effect on digestive function. The described procedure could be beneficial for nonsurgical treatment of benign esophageal tumors in dogs.

Transoral approach for ventral tympanic bulla osteotomy in the dog: A descriptive cadaveric study.

OBJECTIVE: To describe a transoral approach for tympanic bulla osteotomy in the dog. STUDY DESIGN: Anatomic cadaveric study. SAMPLE POPULATION: Fifteen canine cadavers (n = 29 tympanic bullae), including mesaticephalic, dolichocephalic, and brachycephalic breeds. MATERIALS AND METHODS: The oral surface of the tympanic bulla was identified during an anatomical study (3 canine cadavers) and the ventral approach to the tympanic bulla was described (3 canine cadavers). The safety of the technique was assessed (9 canine cadavers, n = 17 bullae) during further anatomical dissections, where a complete approach and drilling of the tympanic bulla were performed. RESULTS: In all cases, tympanic bulla osteotomy was performed without damaging the inner ear, the epitympanic recess contents, and the neurovascular structures. The oral approach to the tympanic bulla was easier in mesaticephalic and dolichocephalic dogs than in brachycephalic breeds. CONCLUSION: This study defines anatomical landmarks for transoral bulla osteotomy, without a high risk of damage to neurovascular and anatomical structures within and/or surrounding the tympanic cavity. This minimally invasive approach to the tympanic bulla is performed via a natural opening, and does not require simultaneous access through the ear canal. In vivo evaluation of this technique is required to verify its safety in clinical cases prior to large scale application.

C8 cross transfer for the treatment of caudal brachial plexus avulsion in three dogs.

OBJECTIVE: To evaluate the cervical nerve 8 cross-transfer technique (C8CT) as a part of surgical treatment of caudal brachial plexus avulsion (BPA) in the dog. STUDY DESIGN: Case series. ANIMALS: Client-owned dogs suspected to have caudal BPA based on neurological examination and electrophysiological testing (n = 3). METHODS: The distal stump of the surgically transected contralateral C8 ventral branch (donor) was bridged to the proximal stump of the avulsed C8 ventral branch (recipient) and secured with 9-0 polypropylene suture under an operating microscope. A carpal panarthrodesis was performed on the injured limb after C8CT. RESULTS: Surgical exploration confirmed avulsion of nerve roots C7, C8, and T1 in all cases. There was no evidence of an iatrogenic effect on the donor forelimb. Gradual improvement in function of the affected forelimb occurred in all dogs, with eventual recovery of voluntary elbow extension. Reinnervation was evident in EMG recordings 6 months postoperatively in all three dogs. Stimulation of the donor C8 ventral branch led to motor evoked potentials in the avulsed side triceps brachialis and radial carpus extensor muscles. Variable functional outcome was observed in the 3 dogs during clinical evaluation 3-4 years after surgery. Digital abrasion wounds, distal interphalangeal infectious arthritis, and self-mutilation necessitated distal phalanx amputation of digits 3 and 4 in 2 dogs. CONCLUSION: C8CT provided partial reconnection of the donor C8 ventral branch to the avulsed brachial plexus in the 3 dogs of this series. Reinnervation resulted in active elbow extension and promoted functional recovery in the affected limb.

Thoracolumbar partial lateral corpectomy for the treatment of chronic intervertebral disc disease in 107 dogs.

BACKGROUND: The purpose of this retrospective study was to assess short-and medium-term outcomes in dogs with chronic ventral thoracolumbar intervertebral disc disease (IVDD) treated by thoracolumbar partial lateral corpectomy (TLPLC). Dogs surgically treated for chronic ventral IVDD by TLPLC were included. For each dog, neurological status evolution and complications were reported. Factors that could have influenced neurological recovery were statistically tested. RESULTS: A total of 107 dogs were included in the study. Before surgery, 67.3 % of the dogs were able to walk, 24.3 % were grade 3, and 8.4 % were grade 4. The median hospitalization time was 3 days, and 82.2 % of the dogs were able to walk at discharge. The medium-term neurological grade was reached at a median time of 2 months. At the medium-term follow-up (median 12 months), 74.3 % of the dogs were neurologically improved, 22.9 % were stable, and 2.8 % were worsened. A total of 91.4 % of dogs were ambulatory, with 58.6 % of dogs having a normal gait. Preoperative neurological grade was significantly associated with the neurological status 24 h after the surgery and at discharge. Dogs with a higher preoperative neurological grade had a better chance of improving but lower odds of walking at 24 h after the surgery and at discharge compared with dogs with a lower preoperative grade. Spinal compression recurrence at the same surgical site was confirmed in 8 cases. CONCLUSION: Even if TLPLC leads to several intra and postoperative complications, this technique is a viable surgical option to treat chronic ventral IVDD.

Indwelling double pigtail ureteral stent combined or not with surgery for feline ureterolithiasis: complications and outcome in 15 cases.

Ureteral obstruction secondary to ureterolithiasis in cats is a challenging situation. Ureteral stenting has recently been introduced to prevent complications that often occurred after ureterotomy or other invasive surgeries. The purpose of this study is to describe the stenting technique and perioperative difficulties, as well as long-term outcome and complications with ureteral stenting in 12 cats with ureteroliths. Fifteen 2.5 Fr soft double pigtail multi-fenestrated ureteral stents were placed in an anterograde fashion under open surgical approaches and with fluoroscopic guidance in 12 cats. Nine cats received a unilateral stent and three received bilateral stents. Ureterotomy or ureteral resection and end-to-end anastomosis were performed in three and four cases, respectively. In six cats, papillotomy was performed to facilitate dilatator and stent placement. All cats recovered well from the surgical procedure, except one cat, which died during the anaesthesia recovery period. Postoperative complications included dysuria (three cases, diagnosed at 15 days, 1 month and 3 months, respectively), urinary tract infection (one case, 1 month after surgery), stent migration requiring stent replacement (one case, 19 months after surgery) and stent obstruction requiring stent removal (three cases with previously end-to-end anastomosis between 2 and 8 months after surgery). Nine cats (75%) were alive at a mean follow-up of 453 ± 194 (123-720) days. The median survival time was >415 days. Stent placement appeared to be a valuable and safe option for treating ureteral obstruction in cats. However, periodic and long-term monitoring of stents is warranted.

Ventral surgical approach to the lumbosacral joint in the dog.

OBJECTIVE: To describe a ventral surgical approach to the lumbosacral (LS) junction, access to L7 and S1, and access to the LS disc. STUDY DESIGN: Cadaveric descriptive study. ANIMALS: Canine cadavers (n = 6). METHODS: A ventral surgical approach to the LS junction was made and local anatomic structures documented. Accessible ventral L7 and S1 vertebral bodies and LS disc were marked with India ink. Total and marked surface areas were calculated. The potential for bicortical and unicortical implant placement was determined in transverse slices of L7 and S1. Exposed ventral disc annulus relative to vertebral canal diameters were measured. RESULTS: Portions of L7 and S1 were accessible in all dogs, but shape and dimensions varied. Ventral access for implant placement was available in both L7 and S1 in every dog. The median sacral artery and vein were in contact with the ventral LS disc annulus in every dog. Accessible ventral annulus were greater than vertebral canal in all dogs. CONCLUSIONS: Ventral approach to the LS junction is possible, with LS discectomy, and implant placement in L7 and S1 vertebral bodies possible from this approach. Injury to, or sacrifice of, the median sacral artery and/or vein may occur in this approach.

Electrophysiological features in dogs with peripheral nerve sheath tumors: 51 cases (1993-2010).

OBJECTIVE: To determine the electrophysiological changes in dogs with peripheral nerve sheath tumors (PNSTs), evaluate the prevalence of these changes, assess the correlation between spontaneous activity in epaxial muscles and proximal invasion by the tumor, and evaluate whether knowledge of electrophysiological changes could be helpful in the imaging diagnosis via CT or MRI. DESIGN: Retrospective case series. ANIMALS: 51 dogs with a histologic (n = 18) or a suspected (33) diagnosis of PNST. PROCEDURES: Clinical, postmortem, and histologic reports and details of electrodiagnostic procedures and CT or MRI reports were studied. Twenty-four CT and 6 MRI reports for dogs with PNSTs were reviewed by a single observer blinded to the diagnosis. RESULTS: Only 2 of the 51 dogs had no electrophysiological changes. The most commonly affected muscles were those innervated by the radial, ulnar, median, tibial-sciatic, and peroneal nerves. Abnormal spontaneous epaxial muscle activity was significantly more frequent in the group with foraminal or spinal invasion by the tumors. Knowledge of the electrophysiological changes increased diagnostic accuracy of CT. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that electrophysiological studies may be sensitive for the detection of PNST and helpful in the imaging diagnosis. Epaxial electromyographic abnormalities appeared to be predictive for intervertebral or vertebral canal invasion by PNSTs in dogs.

Thoracic kyphosis associated with hemivertebra.

OBJECTIVE: To radiographically assess the influence of thoracic hemivertebra on kyphosis and neurologic status in 45 dogs. STUDY DESIGN: Case series. ANIMALS: French Bulldogs without neurologic signs (n = 41) and 4 dogs with compressive spinal cord disease associated with hemivertebra. METHODS: Thoracic spinal radiographs were divided into 3 groups: 1 = dogs with no hemivertebra, 2 = dogs with hemivertebra but no associated neurologic signs, and 3 = dogs with hemivertebra associated with clinical signs. Vertebral canal height, vertebral column angle, and the step between 2 adjacent vertebrae were measured in each group. RESULTS: Vertebral canal height was not significantly different in the 3 groups; however, mean vertebral column angle was significantly (P < .001) different between groups 1 (178°) and 2 (169°), and group 3 (133°). Median cranial step was significantly different between groups (P < .001): 0 mm (group 1), 0.3 mm (group 2), 3 mm (group 3). CONCLUSIONS: Vertebral canal height does not differ between normal dogs and dogs with thoracic hemivertebra. There is an important association between neurologic signs and kyphosis and subluxation. CLINICAL RELEVANCE: Vertebral realignment without vertebral canal opening could lead to spinal cord decompression in dogs affected by thoracic hemivertebra.

One stage functional end-to-end stapled intestinal anastomosis and resection performed by nonexpert surgeons for the treatment of small intestinal obstruction in 30 dogs.

OBJECTIVES: To describe stapled 1-stage functional end-to-end intestinal anastomosis for treatment of small intestinal obstruction in dogs and evaluate outcome when the technique is performed by nonexpert surgeons after limited training in the technique. STUDY DESIGN: Case series. ANIMALS: Dogs (n=30) with intestinal lesions requiring an enterectomy. METHODS: Stapled 1-stage functional end-to-end anastomosis and resection using a GIA-60 and a TA-55 stapling devices were performed under supervision of senior residents and faculty surgeons by junior surgeons previously trained in the technique on pigs. Procedure duration and technical problems were recorded. Short-term results were collected during hospitalization and at suture removal. Long-term outcome was established by clinical and ultrasonographic examinations at least 2 months after surgery and from written questionnaires, completed by owners. RESULTS: Mean±SD procedure duration was 15±12 minutes. Postoperative recovery was uneventful in 25 dogs. One dog had anastomotic leakage, 1 had a localized abscess at the transverse staple line, and 3 dogs developed an incisional abdominal wall abscess. No long-term complications occurred (follow-up, 2-32 months). CONCLUSION: Stapled 1-stage functional end-to-end anastomosis and resection is a fast and safe procedure in the hand of nonexpert but trained surgeons.

Surgical treatment and radiation therapy of frontal lobe meningiomas in 7 dogs.

The cases of 7 adult dogs with generalized seizures managed by surgical excision and radiation therapy for frontal lobe meningiomas were reviewed. The neurological examination was unremarkable in 6 of the 7 dogs. Five dogs were operated on using a bilateral transfrontal sinus approach and 2 using a unilateral sinotemporal approach to the frontal lobe. One dog was euthanized 14 d after surgery; radiation therapy was initiated 3 wk after surgery in the remaining 6 dogs. Long-term follow-up consisted of neurological examination and magnetic resonance imaging (MRI) and/or computed tomography (CT) scan after radiation therapy. The mean survival time for dogs that had surgery and radiation therapy was 18 mo after surgery. Frontal lobe meningiomas have been associated with poor prognosis. However, the surgical approaches used in these cases, combined with radiation therapy, allow a survival rate for frontal lobe meningiomas similar to that for meningiomas located over the cerebral convexities.

Preoperative immunosuppressive therapy and surgery as a treatment for anal furunculosis.

OBJECTIVES: To evaluate the efficacy of combining preoperative immunosuppressive therapy with surgical excision for treatment of anal furunculosis (AF) in dogs. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=25) with stages 1-4 AF. METHODS: Preoperative immunosuppressive therapy was either cyclosporine A (CyA) alone or in combination with ketoconazole (Group 1; n=18), or azathioprine combined with prednisolone (Group 2; n=7). Surgical excision of residual draining tracts, cryptectomy, and anal sacculectomy were performed. Only dogs with postoperative clinical follow-up exceeding 9 months were retained for the study. RESULTS: Both immunosuppressive protocols were effective in reducing progression of AF. Subsequent draining tracts excision, cryptectomy, and anal sacculectomy were bilateral (12 dogs) or unilateral (13 dogs of which 4 had bilateral anal sacculectomy). Postoperative recovery was uneventful, except for 2 dogs that had wound breakdown. Recurrence was not observed in any of the dogs that had bilateral surgical excision and or in 9 dogs that had unilateral excision. CONCLUSION: Preoperative immunosuppressive therapy, combined with bilateral surgical resection of affected tissue consistently, resulted in resolution of AF. Four dogs that had recurrence had unilateral excision despite initial bilateral involvement, suggesting that all diseased tissue should be excised. CLINICAL RELEVANCE: These preliminary results suggest that immunosuppressive therapy before surgical excision for AF yields minimizes recurrence in dogs.

Cutaneous saphenous nerve graft for the treatment of sciatic neurotmesis in a dog.

CASE DESCRIPTION: A 2-year-old Griffon Vendéen was examined because of a 1-month history of right hind limb lameness after a traumatic injury. CLINICAL FINDINGS: Neurologic examination revealed monoplegia and anesthesia of the right hind limb distal to the stifle (femorotibial) joint except for the area supplied by the cutaneous saphenous nerve. Results of electromyographic testing were consistent with a severe lesion of the tibial and peroneal nerves at the level of the stifle joint. TREATMENT AND OUTCOME: Exploratory surgery revealed an 80-mm-long gap in both the peroneal and tibial branches of the right sciatic nerve. A section of the left cutaneous saphenous nerve was interposed to graft the nerve defects. The dog received joint mechanotherapy and electrophysiologic therapy during the reinnervation process. Ten months after surgery, the dog had recovered almost completely. Neurologic examination revealed diminished flexion of the tarsal and digital joints. Repeat electromyographic testing revealed no abnormal spontaneous electrical activity in the right hind limb musculature, and small compound muscle action potentials were recorded in the right interosseous and cranial tibial muscles. CLINICAL RELEVANCE: Without surgical treatment, neurotmesis injury results in poor recovery of motor and sensory functions and may result in amputation. If a nerve defect exists, nerve grafting should be considered, even if the procedure is delayed until well after the injury. The sensory portion of the cutaneous saphenous nerve is a potential source of peripheral nerve for grafting in dogs. Reinnervation is a long-term process and physiologic support and owner involvement are necessary, but nearly complete functional recovery is possible.

Restoration of elbow flexion by performing contralateral lateral thoracic and thoracodorsal nerve transfers after experimental musculocutaneous nerve transection.

OBJECT: The immediate transfer of the right lateral thoracic nerve (LTN) and the thoracodorsal nerve (TDN) to the transected left musculocutaneous nerve (MCN), leading to nerve cross-neurotization, was performed in cats to evaluate reinnervation of the biceps brachii muscle (BBM). METHODS: Surgery to produce cross-neurotization of the MCN was performed in 12 cats (treatment group). Transection of the MCN was performed without attempts at neurotization in three cats (control group). Reinnervation of the BBM was assessed by performing electromyography (EMG) 6 months (14 cats) and 26 months (one cat) postsurgery. True Blue retrograde axonal tracing studies, tensile force measurements (muscle extensometry), and histopathological analyses were performed. All cats in the treatment group recovered voluntary contraction of the BBM and regained elbow flexion. Electromyography revealed no abnormal spontaneous activity in the BBM. Muscle evoked potentials were recorded in that muscle after right C-8 ventral branch stimulation. The muscle contraction strength in the left BBM varied from 108 to 557 g. The BBMs regained their normal appearances. The region of the MCN distal to the anastomosis displayed a normal histological appearance. Fluorescence was detected in the ventral horn of the spinal cord in the right C-8 and T-1 segments. In contrast, in all cats in the control group there was atrophy of the BBM, no EMG signal, and no clinical sign of recovery. There was no contraction of the BBM, no labeled neuron in the spinal cord, and the MCN displayed major degenerative changes. CONCLUSIONS: These findings demonstrate that the LTN and TDN can be used to neurotize injured contralateral brachial plexus nerves and obtain successful reinnervation in cats.

Efficient myelin repair in the macaque spinal cord by autologous grafts of Schwann cells.

Experimental transplantation in rodent models of CNS demyelination has led to the idea that Schwann cells may be candidates for cell therapy in human myelin diseases. Here we investigated the ability of Schwann cells autografts to generate myelin in the demyelinated monkey spinal cord. We report that monkey Schwann cells derived from adult peripheral nerve biopsies retain, after growth factor expansion and transduction with a lentiviral vector encoding green fluorescent protein, the ability to differentiate in vitro into promyelinating cells. When transplanted in the demyelinated nude mouse spinal cord, they promoted functional and anatomical repair of the lesions (n = 12). Furthermore, we obtained evidence by immunohistochemistry (n = 2) and electron microscopy (n = 4) that autologous transplantation of expanded monkey Schwann cells in acute lesions of the monkey spinal cord results in the repair of large areas of demyelination; up to 55% of the axons were remyelinated by donor Schwann cells, the remaining ones being remyelinated by oligodendrocytes. Autologous grafts of Schwann cells may thus be of therapeutic value for myelin repair in the adult CNS.