Study tests ventral ultrasound-guided L7 injection in dogs
Bottom line
A new cadaveric study in Frontiers in Veterinary Science describes a ventral ultrasound-guided approach for perineural injection of the canine L7 spinal nerve, a target that’s clinically relevant in dogs with degenerative lumbosacral disease. In 14 bilateral injections performed in medium- to large-breed canine cadavers, the technique successfully reached the target region 11 times, with success confirmed by CT in all cases and by dissection in one case. The authors reported that all failed injections occurred in overweight dogs, while 5 of 6 injections were successful in cadavers with degenerative lumbosacral changes, suggesting the approach may be especially useful in the population most likely to need it. (frontiersin.org)
Why it matters: For veterinary teams managing dogs with lumbosacral pain, radiculopathy, or suspected L7 nerve involvement, the study adds to growing interest in image-guided, minimally invasive interventions that can both localize pain and potentially deliver more targeted therapy than standard epidural techniques. Degenerative lumbosacral stenosis commonly affects large-breed dogs and can cause pelvic limb lameness, tail weakness, and pain, while current care often ranges from rest, rehabilitation, and medications to epidural steroid injections or surgery. Recent veterinary literature has also pointed to increasing use of foraminal and epidural image-guided procedures for chronic lumbosacral pain, though this new L7 ventral approach still needs in vivo validation before it can be considered practice-ready. (merckvetmanual.com)
What to watch: The next step is whether the technique can be shown to be safe, reproducible, and clinically effective in live dogs, particularly those with naturally occurring degenerative lumbosacral stenosis and higher body condition scores. (frontiersin.org)
Key facts
- Study type
- Cadaveric feasibility study
- Journal
- Frontiers in Veterinary Science
- Target
- Canine L7 spinal nerve
- Approach
- Ventral ultrasound-guided perineural injection
- Sample size
- 14 bilateral injections in medium- to large-breed canine cadavers
- Success rate
- 11 of 14 injections reached the target region
- Confirmation
- CT confirmed success in all cases, and dissection confirmed one case
- Key limitation
- All failed injections occurred in overweight dogs
- Subgroup result
- 5 of 6 injections were successful in cadavers with degenerative lumbosacral changes
A newly published cadaveric feasibility study in Frontiers in Veterinary Science introduces a ventral ultrasound-guided approach for perineural injection of the canine L7 spinal nerve, aiming at a difficult but clinically important target in dogs with lumbosacral disease. The study, led by Romi Dittmann and colleagues at the University of Bern, found successful targeting in 11 of 14 injections, with the authors positioning the technique as a potentially minimally invasive option for dogs with L7 neuropathy or lumbosacral radicular pain. (frontiersin.org)
The work lands in a clinical area where veterinarians still have limited targeted treatment options. Degenerative lumbosacral stenosis, or canine degenerative lumbosacral disease, is a recognized cause of pain in dogs, especially large breeds, and can produce pelvic limb lameness, tail weakness, difficulty using the hind limbs, and, in some cases, incontinence. Standard management typically starts conservatively, with rest, rehabilitation, lifestyle modification, analgesics, and epidural corticosteroid injections, while surgery is generally reserved for refractory pain or neurologic deficits. (merckvetmanual.com)
What makes the new report notable is its focus on the L7 spinal nerve itself. In the study abstract, the authors note that neuropathy of the L7 spinal nerve is common in dogs with degenerative lumbosacral disease, but targeted perineural injection therapy in that region has been sparsely described. Using cadavers of medium- to large-breed dogs, they performed bilateral ultrasound-guided injections of a methylene blue and contrast solution, then assessed placement with CT in all cases and anatomic dissection in one case. Success was achieved in 11 of 14 injections overall, with unsuccessful injections limited to overweight cadavers. In cadavers with degenerative lumbosacral changes, 5 of 6 injections were successful. (frontiersin.org)
The study also fits into a broader evolution of veterinary interventional pain management. A 2025 retrospective cohort study reported long-term outcomes after combined ultrasound- and fluoroscopy-guided foraminal and epidural injections, with or without pulsed radiofrequency at the L7 dorsal root ganglion, in dogs with chronic lumbosacral pain. That paper argued there is increasing interest in minimally invasive, image-guided procedures for canine lumbosacral pain, partly because human transforaminal techniques can place medication closer to the affected nerve root in the ventral epidural space. Earlier cadaver work has also shown that ultrasound-guided approaches at L7 can accurately place injectate near lumbar plexus structures, supporting the idea that this region is technically accessible with ultrasound in dogs. (frontiersin.org)
No independent expert reaction specifically addressing this paper was readily available in the sources reviewed, but the surrounding literature helps frame the likely interest. Reviews of degenerative lumbosacral disease describe it as a complex syndrome in which imaging findings, clinical signs, and pain generators do not always line up neatly, creating demand for interventions that are both diagnostic and therapeutic. That context may explain why targeted nerve-root procedures, rather than broader epidural delivery alone, are drawing more attention. (sciencedirect.com)
Why it matters: For veterinary professionals, the practical question is whether this approach could eventually expand the toolkit between medical management and surgery. If validated in live patients, a ventral ultrasound-guided L7 injection might offer a more targeted option for dogs with suspected radiculopathy, foraminal stenosis, or pain linked specifically to the L7 nerve root. It may also appeal because ultrasound guidance avoids radiation exposure associated with fluoroscopy or CT-guided procedures. At the same time, the findings come with clear limits: this was a cadaver study, the sample was small, and performance appeared less reliable in overweight dogs, a meaningful point in a population where body condition may already complicate spinal disease management. (frontiersin.org)
What to watch: The key next step is in vivo testing, including procedural safety, reproducibility across operators, and whether targeted L7 delivery actually improves pain control or function compared with existing epidural or foraminal approaches. It will also be worth watching whether future studies define which cases benefit most, such as dogs with confirmed foraminal stenosis, disc-associated radiculopathy, or degenerative lumbosacral changes on MRI or CT. (frontiersin.org)