Introduction

Lumbosacral (LS) degenerative disease, canine degenerative lumbosacral stenosis (DLSS), or lumbosacral stenosis, is lower back pain that can be associated with neurologic dysfunction.¹ DLSS often occurs in middle‐aged to older medium‐ to large‐breed dogs with an over‐representation of German Shepherd dogs and working‐type breed dogs.^1–3 There is likely a correlation between work‐related stress and breed predisposition that plays a role in DLSS.^1,2

The vertebral canal and intervertebral foramina at disk spaces L7‐S1 can become narrowed due to disk degeneration, protrusion, or congenital stenosis.¹ In addition, bone and soft tissue proliferation can lead to compression of the cauda equina.¹ The pain associated with DLSS is attributed to direct nerve compression and/or damage to the neighboring soft tissue structures.¹ In humans, this discomfort is known as lower back pain. The direct nerve compression, whether congenital or acquired, causes significant discomfort, which is often exacerbated by certain types of movements.^1,2 Most clinical signs are consistent with lower motor neuron paresis, significant pain on tail manipulation, and owner‐perceived pain.^1–3 However, other clinical signs include intermittent or persistent lameness, reluctance to jump, climb, or stand, spontaneous vocalization for no apparent reason, excessive reaction to manual manipulation and certain movements, and/or worsening lameness induced by exercise.^1–3 If not managed appropriately, DLSS can lead to severe neuropathic pain by overexpression of calcium channels, substance P, and calcitonin gene‐related peptide leading to a chronic pain condition.^1,2,4–6

Diagnosis of DLSS is based on a combination of clinical signs, imaging, and ruling out other differentials.¹ The minimal diagnosis database must include thoracolumbar radiographs to rule out bone‐associated neoplasia, discospondylitis, trauma, or other vertebral anomalies.¹ Contraindications for lumbosacral steroid injections include some bleeding disorders and active skin disease or infection.⁷ In addition, abnormal pelvic anatomy, from congenital or trauma, can make epidurals difficult, however, can be accomplished.⁷

Regarding DLSS within the current veterinary literature, there is no consensus on definitive treatment and no evidence that surgical intervention is better than medical management.^1,2 The current conclusion in human medicine regarding the role of surgical management of humans with lower back pain due to lumbosacral disease is the same as veterinary medicine.^8,9 Options for managing DLSS include oral pain medications, weight loss, physical therapy, lumbosacral steroid injections, and surgical intervention.¹⁰ Some dogs cannot tolerate certain classes of oral medications given daily, with the most commonly given drug class being the non‐steroidal anti‐inflammatories (NSAIDs). NSAIDs can have unfortunate side effects with devastating consequences.¹¹ Further discussion of NSAIDs and other oral pain medications is beyond the scope of this chapter. Strengthening core muscles in dogs with DLSS has been reported as an effective treatment, however, physical rehabilitation alone warrants more investigation.^1,10 In the author’s experience, physical rehabilitation does play an important role in conjunction with lumbosacral steroid injections.

Lumbosacral steroid injections are minimally invasive, fairly easy to perform, and have little to no side effects. Surgical intervention may be considered if the dog does not respond favorably to the series of injections or if the injections become more frequently indicated over time.^1,12,13 A retrospective study, including a client questionnaire, found 79% of dogs had improved clinical signs and 53% had no clinical signs after a series of lumbosacral steroid injections,¹³ and this conclusion was that lumbosacral steroid injections between the seventh lumbar vertebra and the sacrum are safe, effective, and should be considered prior to acute surgical intervention.^12,13

Methylprednisolone acetate (MPA) is a particulate steroid and due to the long duration of action (half‐life of 139 hours) is preferred.¹⁴ Particulate steroids offer a longer duration of action due to the local depot effect, resulting in the continuous release of drugs over a long period of time.^14–17 Other particulate steroids include betamethasone and triamcinolone.¹⁶ MPA should not be given intrathecally, as subarachnoid administration can cause severe meningeal inflammation; therefore, care needs to be taken to ensure the drug is given epidurally.¹⁴ MPA dose for lumbosacral steroid epidural is 1 mg/kg, with a minimum drug volume of 0.5 mL. In addition, 0.1–0.3 mL of saline flush is needed to compensate for volume dose loss within the needle shaft and line.¹³

All steroids can have side effects, and Salmelin et al. reported polyuria, polydipsia, polyphagia, temperament changes, urinary incontinence, and diarrhea in dogs given steroid epidurals. All reported side effects resolved in a few days and required no medical intervention.¹⁵ The author chronicles minimal side effects, and all reported side effects subsided within days of initial discovery and required no medical intervention. Human literature reports up to 33% of inadvertent systemic administration of steroid injectate, causing side effects that are highly variable.^14,16

Lumbosacral steroid injections can be done under general anesthesia or heavy sedation, and the author prefers the latter. Whether utilizing heavy sedation or anesthesia, multiparameter monitoring should be performed, along with an intravenous catheter being placed. Other drugs can be utilized in the LS (lumbosacral) epidural space for pain management; however the author recommends veterinary anesthesia and pain management literature for LS epidural drug specifics as the specifics are beyond the compass of this chapter. Post‐procedure, the author usually administers gabapentin and an NSAID (if not contraindicated) for one to three days post‐injection. This is due to the pain of patient manipulation during the procedure, inflammation caused by the epidural process, and decreased overall inflammation from DLSS. It is not advised to keep dogs on long‐term NSAIDs when receiving steroid epidurals due to cumulative adverse gastrointestinal side effects.¹⁸

Initial treatment interval protocols vary considerably from a single injection to three injections given over two‐week intervals to four injections over a one‐year period.¹³ The author follows an initial treatment protocol extrapolated from the veterinary and human literature. The initial treatment schedule is as follows: preliminary injection (day 1), second injection 14–16 days following the day 1 injection, and third injection 40–50 days following the day 1 injection. The author has several patients who require maintenance injections every 6–12 months. The maintenance injections are administered based on the patient’s response to the initial three‐injection treatment, reoccurrence of clinical signs, and owner‐perceived pain. Along with clinical assessment, the author utilizes a clinical questionnaire for owners to gauge the efficacy of the initial series of injections and subsequent injections that may be required.

Epidural Supplies

• Clippers
  
• Skin preparation solution(s)
  
• Lumbosacral injection needle
  
  
  
  • Tuohy needle or spinal needle with loss‐of‐resistance syringe (Figure 47.1)
    
  • Nerve‐stimulator needle and nerve stimulator (Author preference) (Figure 47.2)
  
  
• Syringes and needles for sedation drugs
  
• Steroid medication and flush (Figure 47.3)
  
• Lidocaine for initial infiltrate (Figure 47.3)
  
• Sterile gloves
  
• +/− Fenestrated drape (Figure 47.4)

Stay updated, free articles. Join our Telegram channel

Join