DEGENERATIVE LUMBOSACRAL STENOSIS: AN ARTICLE IN REVIEW
Megan Davis, DVM
The Article: Clinical signs and outcome of dogs treated medically for degenerative lumbosacral stenosis: 98 cases (2004-2012) Steven de Decker, DVM, PhD; Lauren A. Wawrzenski, BVetMed; Holger A. Volk, DVM, PhD JAVMA, Vol 245, No4, August 15, 2014
Degenerative lumbosacral stenosis (DLSS) is a disorder that creates narrowing of the lumbosacral region and compression of the cauda equina. This is a multifactorial disease and is caused by a combination of many issues, such as Hansen type-II interverteblral disk protrusion, ligamentous and articular process hypertrophy, osteophyte formation, and vertebral misalignment. This is typically a disease of large breed dogs and can cause a clinical signs ranging from pain in the lumbosacral region to severe neurologic deficits in the hind end, and urinary and fecal incontinence.
As many surgical treatments for DLSS have been described, this paper was written to determine to outcomes of dogs treated medically for DLSS and to determine which dogs may be good candidates for medical treatment.
This was a retrospective study using the medical records from the University of London Royal Veterinary College Small Animal Referral Hospital between 2004 and 2012. Inclusion criteria required complete medical records, with neurologic and clinical signs compatible with DLSS, and a diagnosis of DLSS confirmed via 1.5T MRI. Dogs treated both surgically and medically were included in the study. Signalment, duration of symptoms, presence or absence of neurologic signs, concurrent medical conditions, and results of any previous medical treatment was cataloged.
Dogs were then divided into the medical treatment group, surgical treatment group, or both. Medical treatment involved activity restriction for 4 to 6 weeks, an NSAID, +/- Gabapentin. Surgical treatment was a decompresive dorsal lumbosacral laminectomy. Those dogs that initially underwent medical treatment that was unsuccessful and subsequently required surgery were included in both groups. Follow-up information was collected by reviewing exam findings from the 4-6 week recheck after diagnosis of DLSS. Long-term follow-up was via telephone interview with the referring veterinarian and a questionnaire sent to patient owners. Medical treatment failure was defined as progressive or static clinical signs or a change to surgical treatment. Successful treatment was defined as resolution or improvement of clinical signs.
Of the 98 dogs included in the study, 49 were treated medically and 49 were treated surgically. In the medically treated group, neurologic deficits were detected in 33 dogs, previous medical treatment had been received in 33 dogs, concurrent orthopedic conditions were noted in 20 dogs, and concurrent nonorthopedic conditions were detected in 20 dogs. In the surgically treated dogs, neurologic deficit were detected in 43 dogs, 40 dogs had received prior medical treatment (4 of which initially showed improvement with medical treatment), concurrent orthopedic conditions were detected in 15 dogs, and concurrent nonorthopedic conditions were detected in 12 dogs.
When comparing the medically treated and surgically treated dogs, more male dogs were included in the surgically treated group. Additionally, those dogs surgically treated had more neurologic deficits or had received unsuccessful medical management. No statistical difference was noted for age, duration of signs, urinary/fecal incontinence prior to treatment, or those with concurrent issues – orthopedic or nonorthopedic.
Ten of the dogs in the medical group eventually underwent surgery due to unremarkable results noted at the 4-6 week recheck; two of which had decreased tone and movement of the tail. For the remainder of the 21 medically managed dogs, for which there was long-term data, 17 had improvement or resolution of signs and three dogs were euthanized 4, 24, and 35 months after diagnosis of DLSS.
Results of this study demonstrate that dogs who don’t respond to medical management are recommended to proceed with surgical decompression. The overall success rate for medical management of dogs in this study was 55%, which is comparable to previous studies for medical management of cervical and lumbar intervertebral disk herniation. Since 20% of the medically managed dogs eventually underwent successful surgical decompression, this shows that there isn’t necessarily a negative impact on outcome by attempting medical management first. However, it is important to note that none of the dogs that subsequently received surgery had fecal or urinary incontinence. This suggests that dogs with incontinence should not delay surgical treatment by attempting medical management first.
For this study, outcomes assessment for only medically managed dogs was reviewed. This is a problem with the study as many of the dogs that had surgical treatment had more severe neurologic signs at the time of presentation. This study is also limited due to its retrospective nature because spinal cord injury scores may not have been collected (for better comparison of pre- and post- treatment) and also loss of patients to follow-up.