No adverse consequences associated with targeting clinical signs to initiate antimicrobial treatment of postoperative subclinical bacteriuria in dogs following surgical decompression of Hansen type I thoracolumbar disk herniation.

OBJECTIVE: To describe the prevalence of postoperative bacteriuria, clinical course of subclinical bacteriuria in the absence of antimicrobial intervention, clinical signs of bacteriuria that trigger antimicrobial treatment, and outcomes for dogs with subclinical bacteriuria following surgical decompression of acute intervertebral disc herniation (IVDH) Hansen type I. ANIMALS: Twenty client-owned dogs undergoing hemilaminectomy for acute (≤ 6 days) IVDH Hansen type I affecting the thoracolumbar spinal cord segments between August 2018 and January 2019. PROCEDURES: In this prospective study, dogs were serially evaluated at presentation, hospital discharge, 2 weeks postoperatively, and between 4 and 6 weeks postoperatively. Dogs were monitored for clinical signs of bacteriuria, underwent laboratory monitoring (CBC, biochemical analyses, urinalysis, urine bacterial culture), and were scored for neurologic and urinary status. In the absence of clinical signs, bacteriuria was not treated with antimicrobials. RESULTS: Four of the 18 dogs developed bacteriuria without clinical signs 4 days to 4 to 6 weeks after surgery. In all 4 dogs, bacteriuria resulted in lower urinary tract signs 13 to 26 weeks postoperatively. No dogs had evidence of systemic illness despite delaying antimicrobial treatment until clinical signs developed. New-onset incontinence was the only clinical sign in 3 dogs. All bacterial isolates had wide antimicrobial susceptibility. Bacteriuria and clinical signs resolved with beta-lactam antimicrobial treatment. CLINICAL RELEVANCE: Postoperative bacteriuria occurs in some dogs with IVDH Hansen type I and, when present, may lead to clinical signs over time. Clinical signs of bacteriuria may be limited to new-onset urinary incontinence, inappropriate urination, or both. Delaying antimicrobial treatment until clinical signs of bacteriuria developed did not result in adverse consequences or systemic illness.

Relationship of preoperative neurologic score with intervals to regaining micturition and ambulation following surgical treatment of thoracolumbar disk herniation in dogs.

OBJECTIVE To estimate the times required for dogs to regain micturition and ambulation following surgical treatment for thoracolumbar Hansen type I intervertebral disk extrusion (IVDE) and determine whether these variables were associated with preoperative modified Frankel score (MFS). DESIGN Retrospective case series with nested cohort study. ANIMALS 54 dogs weighing < 20 kg (44 lb) that were surgically treated for Hansen type I IVDE at a referral hospital between January and December 2015. PROCEDURES Medical records and CT and MRI data were reviewed. Information was collected regarding dog signalment, type and duration of clinical signs, preoperative MFS, degree of spinal cord compression, type of medical and surgical treatment provided, and intervals from surgery to regaining micturition and ambulation (outcomes). Collected data were evaluated for correlations with outcomes. RESULTS Mean ± SD interval from surgery to regaining micturition was 4.1 ± 4.4 days, and mean interval from surgery to regaining ambulation was 13.8 ± 25.1 days. These intervals differed significantly. Significant negative correlations with MFS were identified for interval to regaining micturition (r = -0.63) and interval to regaining ambulation (r = -0.64). No other correlations with outcome were identified. CONCLUSIONS AND CLINICAL RELEVANCE The amount of time required for dogs to regain micturition and ambulation following surgery for thoracolumbar IVDE was correlated with preoperative severity of clinical signs, as reflected by preoperative MFSs. This information should be useful for pre- and postoperative decision-making and setting of expectations for owners of and clinicians treating affected dogs.

Avaliação clínica de cães com doença do disco intervertebral (Hansen tipo I) submetidos à descompressão cirúrgica: 110 casos / Clinical evaluation of dogs with intervertebral disc disease (Hansen type I) submitted to surgical decompression: 110 cases

O objetivo deste estudo foi identificar cães com doença do disco intervertebral toracolombar (Hansen tipo I) submetidos ao tratamento cirúrgico em um serviço de rotina em neurologia de um hospital veterinário universitário no período de 2006 a 2014, e obter informações a respeito da idade, do sexo, da raça, local da extrusão, interpretação da mielografia, avaliação dos graus de disfunção neurológica, recuperação funcional desses cães e observar a ocorrência de recidiva dos sinais clínicos da doença. A raça mais frequente foi Dachshund (69%), seguida dos cães sem raça definida (14,5%). Os locais mais afetados foram entre T12-T13 (31,9%) e L1-L2 (19,1%). Dos 110 cães, 74 (67,3%) tiveram melhora dos sinais clínicos após o procedimento cirúrgico, sendo 54 (49,1%) considerados satisfatórios e 20 (18,2%), parcialmente satisfatórios. Destes cães, seis (8,1%) cães estavam em grau II, 19 (25,7%) em grau III, 35 (47,3%) em grau IV e 14 (18,9%) em grau V. Pode-se concluir que o tratamento cirúrgico promove recuperação funcional satisfatória na maioria dos cães com extrusão de disco toracolombar. O prognóstico para recuperação funcional após o tratamento cirúrgico é tanto melhor quanto menor for o grau de disfunção neurológica e o percentual de recidiva é baixo em animais submetidos a este tipo de terapia.(AU)

The aim of this study was to identify dogs with thoracolumbar intervertebral disc disease (Hansen type I) submitted for surgical treatment on a routine service in neurology in a university veterinary hospital in 2006-2014, and to get information about age, sex, breed, site of extrusion, interpretation of myelography, evaluation of the degree of neurological dysfunction, functional recovery of these dogs, and to verify the recurrence of clinical signs of disease. The most common breed was Dachshund (69%), followed by mixed breed (14.5%). The most affected sites were between T12-T13 (31.9%) and L1-L2 (19.1%). Of the 110 dogs, 74 (67.3%) improved clinical signs after surgery, 54 (49.1%) satisfactory and 20 (18.2%), in part satisfactory. From these dogs, six (8.1%) dogs were in grade II, 19 (25.7%) in grade III, 35 (47.3%) in grade IV, and 14 (18.9%) in grade V. It can be concluded that satisfactory surgical treatment promotes functional recovery in most dogs with thoracolumbar disk extrusion. The prognosis for functional recovery after surgical treatment is better the lower the degree of neurological dysfunction and the recurrence percentage is lower in dogs subjected to this type of therapy.(AU)

Multiple thoracolumbar partial lateral corpectomies in 17 dogs. / Multiple thorakolumbale partielle laterale Korpektomien bei 17 Hunden.

OBJECTIVE: To report feasibility and outcome of multiple thoracolumbar partial lateral corpectomies (TLPLCs) in dogs with predominantly ventral spinal cord compression caused by intervertebral disc disease (IVDD) in the light of reported decreased spinal stability following single TLPLC. Material und methods: In a retrospective study the records of dogs treated by multiple TLPLCs for ventral spinal cord compression caused by Hansen type I or type II IVDD were reviewed. Presurgical spinal cord compression and postsurgical decompression, as well as slot dimensions were determined based on computed tomography (CT)-myelography images. Neurological outcome was assessed based on repetitive examinations applying a modified Frankel Score as well as on an owner questionnaire. RESULTS: Seventeen dogs with a mean body weight of 20.3 kg (range 4.0-49.0 kg) were included. Fourteen dogs had two TLPLCs, two dogs had three TLPLCs and one dog had four TLPLCs performed. The mean slot depth was 63% of entire vertebral body width, the mean slot height was 29% of the entire vertebral body height, the mean slot length was 25% of the entire vertebral body length and the mean residual vertebral interslot length between two adjacent TLPLCs was 55% of the vertebral body length. At reevaluation 4 weeks after surgery, 6/17 dogs (35.3%) had the same modified Frankel Score as before surgery, whereas 11/17 dogs (64.7%) showed a neurological improvement. According to the owners 78.5% of dogs were walking normally within 6 months after surgery. The mean survival time of 16 dogs, where follow-up was available, was 951 days. CONCLUSION AND CLINICAL RELEVANCE: Multiple spinal cord compressions caused by IVDD can be eliminated by multiple, even consecutive, TLPLCs without the risk of a clinically significant risk of spinal instability.

Autologous bone marrow mononuclear cell transplant and surgical decompression in a dog with chronic spinal cord injury.

OBJECTIVES: In dogs with deep analgesia caused by acute spinal cord injury from thoracolumbar disk herniation, autologous bone marrow mononuclear cell transplant may improve recovery. The purpose of the present study was to evaluate autologous bone marrow mononuclear cell transplant in a dog that had paraplegia and deep analgesia caused by chronic spinal cord injury. MATERIALS AND METHODS: Autologous bone marrow mononuclear cell transplant was performed in a dog having paraplegia and analgesia for 3 years that was caused by a chronic spinal cord injury secondary to Hansen type I thoracolumbar disk herniation. Functional recovery was evaluated with electrophysiologic studies and the Texas Spinal Cord Injury Scale. RESULTS: Somatosensory evoked potentials were absent before transplant but were detected after transplant. Functional improvement was noted (Texas Spinal Cord Injury Scale: before transplant, 0; after transplant, 6). No adverse events were observed. CONCLUSIONS: Autologous bone marrow mononuclear cell transplant into the subarachnoid space may be a safe and beneficial treatment for chronic spinal cord injury in dogs.

Hemilaminectomy for thoracolumbar Hansen Type I intervertebral disk disease in ambulatory dogs with or without neurologic deficits: 39 cases (2008-2010).

OBJECTIVE: To describe prognostic factors, outcome, and time to recovery among ambulatory dogs having hemilaminectomy for Hansen Type I intervertebral disk disease. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 38; 39 hemilaminectomies). METHODS: Medical records (January 2008-May 2010) on all dogs that had hemilaminectomy for Hansen Type I intervertebral disk disease were reviewed. Records for dogs that were ambulatory preoperatively were analyzed for signalment, duration and severity of signs, presence of neurologic deficits, and postoperative outcome. Dogs were categorized based on Frankel score and subcategorized by their level of conscious proprioceptive (CP) deficit. Postoperatively, time to ambulation and to regain normal CP responses was recorded. Results for each group were compared using a χ(2) test and considered significant when P < .05. Recovery times were analyzed using a Cox proportional hazards model. RESULTS: Seven dogs were categorized as modified Frankel grade I preoperatively and 32 dogs as grade II with varying levels of deficits (1 of these dogs had previously been operated as grade II and was reoperated again as grade II). Increasing degree of CP deficit preoperatively was significantly correlated with longer time to ambulation (P = .005) as well as longer time to CP normal (P = .01). Duration of signs was not significantly correlated with time to ambulation or neurologic recovery for either grade I or II dogs. CONCLUSIONS: Most dogs recovered well with surgical decompression. Increasing degree of deficits preoperatively is significantly correlated with longer recovery time.

Assessment of the usefulness of the fenestration method in cases of disc extrusion in the cervical and thoraco-lumbar spine in chondrodystrophic dogs.

The aim of this paper was to assess the effectiveness of treatment of Type I (according to Hansen) intervertebral disc extrusion using the fenestration method. The evaluated clinical material included 37 chondrodystrophic dogs in which multiple fenestration (from 2 to 6 intervertebral spaces) was performed. Dachshunds comprised 86.5% of patients. All dogs were administered corticosteroids during the operation. A mass similar to a slightly jelly-like yogurt, cottage cheese or plaster-like consistency was extracted. In one case a post-surgical pyogenic infection of the wound occured. In two cases, a deterioration in the neurological state followed the fenestration procedure of the cervical spine. In one case of thoraco-lumbar spine fenestration, a deterioration of clinical state was found. Recovery was observed after disc extrusion from the cervical spine in 8 out of 11 dogs, from the thoraco-lumbar spine in 12 out of 14 dogs with the 2nd grade clinical signs and in 11 out of 12 dogs with the 3rd grade clinical sings. In 6 dogs, recurrence of first or second grade clinical signs occurred, but only half of them had to undergo treatment. The probability of dog recovery did not depend on the degree of symptom intensity in a statistically significant way (p=0.11) or on the duration of the disease before the surgical treatment (p=0.87).

Influence of intervertebral disc fenestration at the herniation site in association with hemilaminectomy on recurrence in chondrodystrophic dogs with thoracolumbar disc disease: a prospective MRI study.

OBJECTIVE: To describe the influence of fenestration at the disc herniation site on recurrence in thoracolumbar disc disease of chondrodystrophoid dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: Chondrodystrophic dogs (n=19). METHODS: Dogs were divided into 2 groups: group 1 (9 dogs) had thoracolumbar disc extrusion (Hansen type I) treated by hemilaminectomy and concomitant fenestration of the affected intervertebral disc and group 2 (10 dogs) had hemilaminectomy without fenestration. All dogs had 3 magnetic resonance imaging (MRI) examinations: preoperatively, immediately postoperatively to assess removal of herniated disc material, and again 6 weeks after surgery. RESULTS: There were 13 male and 6 female dogs; mean age, 7.1 years. Thoracolumbar disc herniation was confirmed with MRI. Immediate post surgical MRI revealed that the herniated disc removal was complete in all but 1 dog and that fenestration did not lead to complete removal of nucleus pulposus within the intervertebral disc space. On the 3rd MRI examination, none of the group 1 dogs had further disc material herniation at the fenestrated site. Six of the 10 group 2 dogs had a recurrence of herniation leading to clinical signs in 3 dogs (pain in 2 dogs, paresis in 1 dog). CONCLUSION: In thoracolumbar disc herniation, fenestration of the affected intervertebral disc space prevents further extrusion of disc material. CLINICAL RELEVANCE: Fenestration reduces the risk of early recurrence of disc herniation and associated postoperative complications.

Outcome and prognostic factors in non-ambulatory Hansen Type I intervertebral disc extrusions: 308 cases.

Thoracolumbar intervertebral disc disease is the most common cause of caudal paresis in dogs. Whilst the pathogenesis of the extrusion has been widely studied, treatment protocols and prognostic factors relating to outcome remain controversial. Recent studies have examined a multitude of factors relating to time to regain ambulation after decompressive surgery. Most intervertebral disc herniations occur in the thoracolumbar region, causing upper motor neuron signs in the rear limbs, which are thought to have a more favourable prognosis compared to the lower motor neuron signs created by herniation of an intervertebral disc in the caudal lumbar region. Due to the potential disruption of the lumbar intumescence, lower motor neuron signs have been reported as having a less favourable prognosis. The purpose of this study was to evaluate the intervertebral disc space as a prognostic factor relating to ambulatory outcome and time to ambulation after decompressive surgery. Hansen Type I intervertebral disc extrusions were studied in 308 non-ambulatory dogs. Preoperative and postoperative neurological status, corticosteroid use, signalment, intervertebral disc space, postoperative physical rehabilitation, previous hemilaminectomy surgery, disc fenestration, return to ambulation, and time to ambulation were reviewed.

Recurrence of thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs after surgical decompression with or without prophylactic fenestration: 265 cases (1995-1999).

OBJECTIVES: To evaluate a population of chondrodystrophic dogs treated for Hansen type 1 intervertebral disk (IVD) disease by surgical decompression with or without prophylactic fenestration and determine the rate and location of surgically confirmed recurrence of intervertebral disk extrusion. ANIMALS: 265 dogs. STUDY DESIGN: Retrospective study. PROCEDURES: Medical records of dogs that underwent spinal decompression between 1995 and 1999 were reviewed. RESULTS: 3 (4.9%) dogs were euthanatized or died prior to discharge. Fenestration was performed in 252 dogs, including 37 (14.7%) at the site of decompression only, 48 (19%) at 3 to 4 disk spaces, and 167 (66%) at 5 to 7 disk spaces. There were 12 instances of recurrent disk extrusion confirmed by removal of disk at a second surgery 3.5 to 33 months after the first surgery. Recurrence was always at a new disk space, and rates did not significantly differ between dogs that underwent single or multiple fenestrations. Two recurrences were at a previously fenestrated disk space. Seven recurrences were at a site immediately adjacent to a fenestrated disk space, and 5 recurrences were at L4-5. CONCLUSIONS AND CLINICAL RELEVANCE: Prophylactic fenestration is generally successful in preventing future disk extrusions at fenestrated disk spaces. Prospective evaluation is still required to determine whether fenestration decreases the overall rate of recurrence. Prophylactic fenestration could promote disk extrusion at adjacent, nonfenestrated disk spaces. This could have a substantial clinical impact if recurrence develops at L4-5.

Prognostic indicators for time to ambulation after surgical decompression in nonambulatory dogs with acute thoracolumbar disk extrusions: 112 cases.

OBJECTIVES: To determine prognostic indicators for time to ambulation after surgical decompression in nonambulatory dogs with intact pain sensation and acute Hansen type-1 disk extrusions. STUDY DESIGN: Retrospective clinical study. ANIMALS: One-hundred twelve dogs with Hansen type-I disk extrusions that had decompressive hemilaminectomy or dorsal laminectomy. METHODS: All dogs had thoracolumbar disk extrusion and were nonambulatory with intact pain sensation at admission. Variables considered included age, weight, voluntary motor function at time of anesthetic induction, glucocorticoid use, times from onset of nonambulatory status to admission and surgical decompression, time in hospital to surgical decompression, anesthetic time, surgical time, number of contrast injections required to perform a diagnostic myelogram, postoperative pain sensation, and postoperative voluntary motor function. Time to ambulation was defined as the number of days from surgical decompression until the dog was able to stand and take a series of steps without assistance. RESULTS: One-hundred seven dogs (96%) were able to ambulate within 3 months. The mean time to ambulation was 12.9 days and was significantly shorter if dogs had postoperative voluntary motor function (7.9 days v 16.4 days, P <.0001). No other variable had a significant association with time to ambulation. CONCLUSIONS: Few perioperative variables have prognostic value for return to ambulation. Nonambulatory dogs with intact pain sensation and Hansen type-1 disk extrusions in the thoracolumbar spine that are treated with surgical decompression have a favorable prognosis. CLINICAL RELEVANCE: The presence of postoperative voluntary motor function is a favorable prognostic indicator for early return to ambulation.