Tumor volume as a predictive parameter in the sequential therapy (induction chemotherapy) of head and neck squamous cell carcinomas.

PURPOSE: Tumor volume in locally advanced head and neck squamous cell carcinomas (LAHNSCC) treated by induction chemotherapy (ICT) and followed by radiochemotherapy (RCT) was measured. The presence of potential correlation of initial tumor volume and volume reduction after ICT and RCT with remission status, overall survival (OS) and disease-free survival (DFS) were investigated. Furthermore, reliability of approximation of the tumor volume relying on its diameter to manual three-dimensional measurement was assessed. METHODS: Data of patients with LAHNSCC treated by ICT consisting of docetaxel, cisplatin, and 5-fluorouracil (TPF) followed by definite RCT were retrospectively analyzed. The tumor volume was calculated slice-by-slice in contrast-enhanced CT or MRI before and after ICT as well as after complete treatment. The volume was compared to radiologic remission status, correlated with OS and DFS, and to volume estimation using tumor diameter. RESULT: 65 patients were included. Primary tumor volume did not correlate with complete remission rate (CR) after ICT and RCT, OS or DFS. The change in tumor volume between baseline imaging and post-RCT had a significant impact on OS (p = 0.026) and DFS (p = 0.028). The agreement between tumor volume and radiologic remission was 72.14%. CONCLUSION: The initial tumor volume had no influence on CR, OS or DFS. A severe response to ICT did not predict a powerful RCT outcome. The change in tumor volume post-RCT had an impact on OS and DFS. Tumor volume estimation using its diameter seems to be a reliable method.

Differences in Epidural Pathology between Cervical and Thoracolumbar Intervertebral Disk Extrusions in Dogs.

BACKGROUND: Although the basic pathophysiology is the same in both cervical and thoracolumbar intervertebral disk (IVD) extrusions, there are considerable clinical differences that have only been partially explained. HYPOTHESIS/OBJECTIVES: The epidural inflammatory response differs between cervical and thoracolumbar IVD extrusions. ANIMALS: Fifty-five dogs with cervical and 80 dogs with thoracolumbar IVD extrusions. METHODS: Clinical data and histopathologic variables were investigated. Associations between severity of epidural inflammation and clinical and pathologic variables, impact of chondrodystrophic phenotype, and localization (cervical versus thoracolumbar) were evaluated statistically. RESULTS: Dogs with cervical IVD extrusion were significantly older (P < 0.001), had less severe and longer duration of neurologic signs (both P < 0.001), were more painful (P = 0.038), and had a better outcome (P = 0.005) than dogs with a thoracolumbar IVD extrusion. On histopathology, cervical epidural material had less severe calcification (P = 0.002) and inflammation (P < 0.001). No significant differences regarding chondrodystrophic phenotype were found. CONCLUSION AND CLINICAL IMPORTANCE: There was significantly less intensive inflammatory response in the cervical epidural space. This observation correlated positively with less nucleus pulposus calcification in cervical extrusions indicating biochemical, metabolic, and biomechanical differences between the 2 locations, which remain to be characterized in future studies.

Incidence of Abnormalities of the Second and Third Cervical Vertebral Junction in Dogs with Atlantoaxial Instability: A Multicentre Study.

Objective To evaluate the occurrence and frequency of abnormalities at the second and third cervical vertebral junction (C2/3) in dogs with and without atlantoaxial instability (AAI). Study Design Retrospective multi-institutional case-controlled case series. Animals One hundred and seventeen dogs with AAI and 117 dogs without AAI. Methods Radiographs, together with computer tomographic images or magnetic resonance images or both, of the cranial cervical spine of dogs were reviewed for the presence or absence of intervertebral disc-related anomalies, osseous fusion of the vertebrae, spondylosis, or any other anomaly of the C2/3. Results The incidence of anomalies affecting the C2/3 in dogs with AAI was 38.46% (n = 45) and in the control group it was 11.97% (n = 14). The majority of the observed anomalies involved the intervertebral disc. In conjunction with AAI, intervertebral disc-related anomalies were noted in 33.34%, spondylosis in 2.56%, osseous fusion in 1.71% and a hypoplasia of the spinous process in 0.85% of the cases. Summarized under the term intervertebral disc-related anomalies, a morphological alteration of the intervertebral disc was noted in 10 cases with AAI, characterized by a spherical outer shape and a minimally reduced size and a dorsal positioning in the intervertebral space. Conclusion There is a significantly higher incidence of anomalies affecting the C2/3 in association with AAI. In conjunction with AAI, intervertebral disc-related anomalies are the most frequent pathological finding affecting the C2/3.

Endothelin-1 Immunoreactivity and its Association with Intramedullary Hemorrhage and Myelomalacia in Naturally Occurring Disk Extrusion in Dogs.

BACKGROUND: The pathophysiology of ascending/descending myelomalacia (ADMM) after canine intervertebral disk (IVD) extrusion remains poorly understood. Vasoactive molecules might contribute. HYPOTHESIS/OBJECTIVES: To investigate the immunoreactivity of endothelin-1 (ET-1) in the uninjured and injured spinal cord of dogs and its potential association with intramedullary hemorrhage and extension of myelomalacia. ANIMALS: Eleven normal control and 34 dogs with thoracolumbar IVD extrusion. METHODS: Spinal cord tissue of dogs retrospectively selected from our histopathologic database was examined histologically at the level of the extrusion (center) and in segments remote from the center. Endothelin-1 immunoreactivity was examined immunohistochemically and by in situ hybridization. Associations between the immunoreactivity for ET-1 and the severity of intramedullary hemorrhage or the extension of myelomalacia were examined. RESULTS: Endothelin-1 was expressed by astrocytes, macrophages, and neurons and only rarely by endothelial cells in all dogs. At the center, ET-1 immunoreactivity was significantly higher in astrocytes (median score 4.02) and lower in neurons (3.21) than in control dogs (3.0 and 4.54) (P < .001; P = .004) irrespective of the grade of hemorrhage or myelomalacia. In both astrocytes and neurons, there was a higher ET-1 immunoreactivity in spinal cord regions remote from the center (4.58 and 4.15) than in the center itself (P = .013; P = .001). ET-1 mRNA was present in nearly all neurons with variable intensity, but not in astrocytes. CONCLUSION AND CLINICAL IMPORTANCE: Enhanced ET-1 immunoreactivity over multiple spinal cord segments after IVD extrusion might play a role in the pathogenesis of ADMM. More effective quantitative techniques are required.

Biomechanical properties of the atlantoaxial joint with naturally-occurring instability in a toy breed dog. A comparative descriptive cadaveric study.

The biomechanical properties of the atlanto-axial joint in a young Yorkshire Terrier dog with spontaneous atlantoaxial instability were compared to those of another young toy breed dog with a healthy atlantoaxial joint. The range-of-motion was increased in flexion and lateral bending in the unstable joint. In addition, lateral bending led to torsion and dorsal dislocation of the axis within the atlas. On gross examination, the dens ligaments were absent and a longitudinal tear of the tectorial membrane was observed. These findings suggest that both ventral and lateral flexion may lead to severe spinal cord compression, and that the tectorial membrane may play a protective role in some cases of atlantoaxial instability.

Influence of two types of self-retaining retractors on multifidus muscle blood flow during dorsolateral thoracolumbar hemilaminectomy in dogs.

OBJECTIVES: To assess the influence of the use of Gelpi and Grevel retractors on multifidus muscle blood flow during hemilaminectomy, using a dorsolateral approach, for acute disc extrusion in dogs as measured by laser speckle contrast imaging (LSCI). METHODS: Blood flow in the multifidus muscles was measured intra-operatively using LSCI prior to insertion of the retractors, immediately after hemilaminectomy and removal of the retractors, and after 10 minutes of lavage of the surgical site. Plasma creatine kinase levels were measured preoperatively and 12-24 hours postoperatively. RESULTS: Muscular blood flow was significantly decreased following retraction and remained lower than initial values 10 minutes after lavage in all dogs. The decrease in blood flow was significantly greater with Gelpi retractors (n = 8) than with Grevel retractors (n = 10). No significant relation was found between the duration of retraction and postoperative changes in creatine kinase levels or blood flow. CLINICAL SIGNIFICANCE: Findings in this study demonstrate a drop in blood flow within the multifidus muscles using the dorsolateral approach regardless of retractor type used. Gelpi retractors seem to have greater influence on muscular blood flow than Grevel retractors. Further studies are warranted to confirm this second finding.

Congenital cervical kyphosis in two young sighthounds.

INTRODUCTION: Cervical vertebral (C) malformation is rarely reported in large breed dogs. Congenital cervical kyphosis (CCK) may result from defects of vertebral segmentation, failure of formation or both. This report describes two cases of C3-C4 CCK in young sighthounds, treated surgically. CASE DESCRIPTION: An 18-month-old female Deerhound and a six-week-old female Borzoi dog were presented because of the complaints of reluctance to exercise and signs of of neck pain. Both dogs were neurologically normal. Diagnostic imaging revealed C3-C4 deformity, moderate kyphosis, and spinal canal stenosis associated with chronic spinal cord pressure atrophy. Both dogs underwent surgical treatment. RESULTS: A staged two-step surgery starting with dorsal decompression was elected in the Deerhound. After the first surgical procedure, the dog developed focal myelomalacia and phrenic nerve paralysis and was euthanatized. A ventral distraction-fusion technique with two locking plates was performed in the Borzoi. This patient recovered uneventfully and long-term follow-up computed tomography revealed complete spondylodesis. CLINICAL SIGNIFICANCE: Until now, CCK has only been described in sighthounds. Congenital cervical kyphosis might be considered a differential diagnosis in these breeds that are presented with signs of cervical pain. Ventral realignment-fusion and bone grafting may be considered for surgical treatment, although the earliest age at which this procedure can and should be performed remains unclear.

Atlantoaxial epidural abscess secondary to grass awn migration in a dog.

A two-year-old female Lucerne Hound was presented with a one-week history of signs of progressive neck pain, inappetence, apathy, and an elevated rectal temperature. Findings of magnetic resonance imaging (MRI) were consistent with a foreign body abscess in the epidural space at the level of the first and second cervical vertebrae. A left-sided dorso-lateral atlantoaxial approach was performed, revealing an epidural abscess containing a grass awn. The clinical signs resolved within three days of surgery and the dog made a full recovery. This case report shows that grass awns can migrate to the atlantoaxial region in dogs and MRI findings lead to a suspicion of caudo-cranial migration within the spinal canal.

Far lateral lumbar disc extrusion: MRI findings and surgical treatment.

This case report describes the magnetic resonance imaging (MRI) findings and the treatment of a far lateral extrusion of disc material at the sixth and seventh lumbar vertebrae (L6-L7) in a five-year-old male Alpine Dachsbracke dog referred to our hospital for investigation of the complaint of a one week progressive lameness in the left pelvic limb and poorly localized back pain. An extra-foraminal left lateral disc herniation impinging on the sixth lumbar nerve root was diagnosed by MRI examinations. Due to the far lateral position of the extruded disc material on MRI, surgical opening of the spinal canal was not necessary. Removal of the herniated soft disc material impinging on the L6 nerve root, and fenestration of the L6-L7 disc was performed laterally. To the author's knowledge 'far-lateral' disc herniation beyond the neuroforamen without any spinal canal contact has not been described in dogs until now. A complete recovery with no evidence of pain was achieved only after a couple of weeks after surgery. We acknowledge that it is possible that other pathological mechanisms may have contributed to clinical signs and to a delayed recovery.

Clinical and pathological analysis of epidural inflammation in intervertebral disk extrusion in dogs.

BACKGROUND: Little is known about the pathologic changes in the epidural space after intervertebral disk (IVD) extrusion in the dog. OBJECTIVES: To analyze the pathology of the epidural inflammatory response, and to search for correlations between this process and clinical findings. METHODS: Clinical data from 105 chondrodystrophic (CD) and nonchondrodystrophic (NCD) dogs with IVD extrusion were recorded. Epidural material from these dogs was examined histopathologically and immunohistochemically. Using statistical analysis, we searched for correlations between severity of epidural inflammation and various clinical and pathologic variables. RESULTS: Most dogs exhibited an epidural inflammatory response, ranging from acute invasion of neutrophils to formation of chronic granulation tissue. The mononuclear inflammatory infiltrates consisted mostly of monocytes and macrophages and only few T and B cells. Surprisingly, chronic inflammatory patterns also were found in animals with an acute clinical history. Severity of the epidural inflammation correlated with degree of the epidural hemorrhage and nucleus pulposus calcification (P = .003 and .040), but not with age, chondrodystrophic phenotype, neurologic grade, back pain, pretreatment, or duration. The degree of inflammation was statistically (P = .021) inversely correlated with the ability to regain ambulation. CONCLUSION AND CLINICAL IMPORTANCE: Epidural inflammation occurs in the majority of dogs with IVD extrusion and may develop long before the onset of clinical signs. Presence of calcified IVD material and hemorrhage in the epidural space may be the triggers of this lesion rather than an adaptive immune response to the nucleus pulposus as suggested in previous studies. Because epidural inflammation may affect outcome, further research is warranted.

Correlations between severity of clinical signs and histopathological changes in 60 dogs with spinal cord injury associated with acute thoracolumbar intervertebral disc disease.

The outcome of spinal surgery in dogs with absent voluntary motor function and nociception following intervertebral disc (IVD) herniation is highly variable, which likely attests to differences in the severity of spinal cord damage. This retrospective study evaluated the extent to which neurological signs correlated with histologically detected spinal cord damage in 60 dogs that were euthanased because of thoracolumbar IVD herniation. Clinical neurological grades correlated significantly with the extent of white matter damage (P<0.001). However, loss of nociception also occurred in 6/31 (19%) dogs with relatively mild histological changes. The duration of clinical signs, Schiff-Sherrington posture, loss of reflexes and pain on spinal palpation were not significantly associated with the severity of spinal cord damage. Although clinical-pathological correlation was generally good, some clinical signs frequently thought to indicate severe cord injury did not always correlate with the degree of cord damage, suggesting functional rather than structural impairment in some cases.

An indirect reduction technique for ventral stabilization of atlantoaxial instability in miniature breed dogs.

OBJECTIVE: To describe an indirect reduction method for ventral fixation of atlantoaxial instability. STUDY: Retrospective study. ANIMALS: Miniature dogs (n = 5) with atlanto-axial instability. MATERIALS AND METHODS: For surgery, the anaesthetized dogs were positioned in dorsal recumbency. A standard ventral midline cranial cervical approach was used. The median part of the cervical (C) vertebral bodies of C1, C2 and C3 were exposed. After excision of the atlantoaxial joint capsule, a fenestration was performed at the C2-C3 intervertebral disc with a narrow slot in the ventral cranial endplate of C3. A midline incision of the atlanto-occipital membrane at the intercondyloid incisure was made to provide access to the spinal canal. Longitudinal distraction and realignment of C1-C2 were obtained by placing the tips of a Gelpi retractor in the two openings created. Overdistraction allowed removal of articular cartilage between C1-C2. Closing of the C1-C2 articular gap was finally achieved by applying lateral distraction with a second Gelpi retractor placed between the paired longus colli muscles. Fixation could then be performed without further stabilization. RESULTS: No intraoperative complications were observed. Recovery was uneventful. CONCLUSIONS: The described technique offered good surgical visibility and permitted safe reduction of atlantoaxial subluxation. CLINICAL RELEVANCE: By reducing manipulation and instrumentation necessary for reduction of atlantoaxial instability, the described technique may be advantageous in toy-breed dogs.

Use of a 1.5 mm butterfly locking plate for stabilization of atlantoaxial pathology in three toy breed dogs.

The objective of this study was to describe the use of a titanium 1.5 mm locking plate in the stabilization of atlantoaxial pathology in three toy breed dogs. Two dogs with atlantoaxial subluxation and another dog with an axial fracture, confirmed by diagnostic imaging, were stabilized via a ventral approach with a 1.5 mm titanium 5-hole locking butterfly-plate. Surgical reduction and stabilization were assessed by computed tomography and radiography after surgery. Follow-up evaluation for resolution of neurological signs and possible complications was performed in all three dogs. For long-term assessment, a telephone follow-up was performed. A considerable improvement of neurological signs occurred within two to four weeks after surgery. An excellent clinical outcome was identified in all three patients. Adequate stabilization and resolution of neurological signs in all three dogs was achieved. The stabilization of atlantoaxial surgical conditions in toy breeds with the 1.5 mm titanium 5-hole butterfly locking plate appears to be an effective means of surgical treatment.

[New aspects in the treatment of disc herniation in the dog]. / Neue Aspekte in der Behandlung des Bandscheibenvorfalls beim Hund: Eine Ubersicht.

Disc herniation is one of the main research topics at the Tierspital Berne. In this review article about canine disc disease, results from recent clinical research are presented and integrated to the actual knowledge about the disease. These new results deal mainly with neurosurgery/neuroradiology and especially focus on therapeutic value of commonly used treatment methods (hemilaminectomy, fenestration, durotomy, lateral corpectomy) in order to further improve therapeutical results in future.

Non-selective cutaneous sensory neurectomy as an alternative treatment for auto-mutilation lesion following arthrodesis in three dogs.

OBJECTIVE: To describe an alternative method for the treatment of non-responsive self-mutilation injuries in three dogs after carpal/tarsal arthrodesis. STUDY DESIGN: Case series ANIMALS: Two dogs with carpal injury and one dog with tarsal injury treated by arthrodesis METHODS: All dogs developed self-mutilation injuries due to licking and/or chewing of the toes within 21-52 days of surgery. Clinical signs did not resolve within one week after conservative treatment with wound debridement and protective bandages. Following general anaesthesia, a deep horseshoe-shaped skin incision, including the subdermal tissue, was performed proximal to the self-mutilation injury transecting the sensory cutaneous afferent nerves. The skin incision was closed with simple interrupted sutures. RESULTS: All wounds healed without complication. Self-mutilation resolved completely within 24 hours after surgery in all dogs. No recurrence was observed (5 months to 3 years). CONCLUSION: Non-selective cutaneous sensory neurectomy may lead to resolution of self-mutilation following arthrodesis in dogs. CLINICAL RELEVANCE: Failure of conservative treatment in self-mutilation injuries often leads to toe or limb amputation as a last resort. The technique described in this case series is a simple procedure that should be considered prior to amputation. The outcome of this procedure in dogs self-multilating due to neurological or behavioral disturbances unrelated to carpal or tarsal arthrodesis is not known.

Chronic intervertebral disk herniation associated with fused vertebrae treated by vertebral lateral corpectomy in a cat.

A 10-year-old Domestic Shorthair cat was admitted for chronic ambulatory paraparesis and a spinal malformation. The clinical examination revealed paraparesis accentuated on the left side. Thoracolumbar radiographs revealed a spinal malformation with a narrowed intervertebral space between L1 and L2, and a dorsal fusion at the level of L2-L3 with a common dorsal process. Magnetic resonance imaging (MRI) revealed an intervertebral disk herniation with a ventral compression of the spinal cord at the level of L1/2. A standard vertebral lateral corpectomy with a foraminotomy was performed with a good outcome.

Comparative study of vertebral fractures and luxations in dogs and cats.

The purpose of this retrospective study was to compare patterns of vertebral fractures and luxations in 42 cats and 47 dogs, and to evaluate the impact of species-related differences on clinical outcome. Data regarding aetiology, neurological status, radiographic appearance and follow-up were compared between the groups. The thoracolumbar (Th3-L3) area was the most commonly affected location in both cats (49%) and dogs (58%). No lesions were observed in the cervical vertebral segments in cats, and none of the cats showed any signs of a Schiff-Sherrington syndrome. Vertebral luxations were significantly more frequent in dogs (20%) than in cats (6%), whereas combined fracture-luxations occurred significantly more often in cats (65%) than in dogs (37%). Caudal vertebral segment displacement was mostly dorsal in cats and ventral in dogs, with a significant difference in direction between cats and large dogs. The clinical outcome did not differ significantly between the two populations, and was poor in most cases (cats: 61%; dogs: 56%). The degree of dislocation and axis deviation were both significantly associated with a worse outcome in dogs, but not in cats. Although several differences in vertebral fractures and luxation patterns exist between cats and dogs, these generally do not seem to affect outcome.

Lumbar spinal 'juxtaarticular' cyst in a Gordon setter.

An 11-year-old Gordon setter bitch was presented with a history of progressive weakness in the right hind limb associated with pain in the lumbar spine. Neurological deficits consisted of ataxia, monoparesis, muscle atrophy and spontaneous over-knuckling of the affected limb. A large 'juxtaarticular' cyst located in a right dorsolateral position of the intervertebral foramen at L3-L4 was diagnosed by magnetic resonance imaging. The cyst was removed through a modified laminectomy. The dog recovered quickly and returned to the owners 4 days after surgery with slight neurological symptoms. During the follow-up examination 2 and 6 months later, the Setter showed normal gait and neurological examination.

Adenocarcinoma metastasis of the intertransversarius cervicis muscle eliciting a right forelimb lameness in a dog.

This article describes identification of a metastatic adenocarcinoma to the intertransversarius cervicis muscle using magnetic resonance imaging (MRI) in a dog that presented with chronic lameness of the right forelimb. Magnetic resonance imaging revealed a right sided, ovoid signal abnormality within the intertransversarius cervicis muscle lateral to the sixth cervical (C6) vertebra. The lesion was uniform, hyperintense on T2- and isointense on T1-weighted images to muscle and exhibited uniform contrast enhancement on T1-weighted images. The MRI findings were consistent with a neoplasia. Surgical excision was performed. Histopathological diagnosis was metastatic fibrous adenocarcinoma. The dog recovered rapidly but 6 months post-operatively he was killed because of lung metastases. Necropsy was declined and the primary tumour could not be identified.

Influence of surgical approach on the efficacy of the intervertebral disk fenestration: a cadaveric study.

OBJECTIVES: To investigate the influence of different approach angles on the amount of nucleus pulposus removed during intervertebral disc fenestration in dogs. METHODS: Twenty cadavers of beagle dogs were randomly divided into four groups: a control group and three treatment groups in which intervertebral fenestration was performed using either a dorsal, dorsolateral or lateral approach between the 12th thoracic and second lumbar spaces. The volume of nucleus pulposus, the weight of the residual nucleus pulposus and the angle of the working sector were measured. The ratio of the residual nucleus pulposus weight to the nucleus pulposus volume was used to evaluate the efficacy of the performed fenestration. Data were analysed with Kruskal-Wallis analysis of variance between groups on ranks with correction for ties and Bonferroni correction for multiple comparisons. Correlation between ratio and working angle was calculated using a Spearman's rank test (P<0.05). RESULTS: The calculated ratio of nuclear weight to volume was significantly less in the lateral approach group than that in the other groups. The working sector was widest in the dorsolateral approach group, but this did not correlate with efficient fenestration. CLINICAL SIGNIFICANCE: Using the lateral approach for intervertebral disc fenestration may increase the efficiency of the fenestration procedure.