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A six -year-old female spayed Rottweiler was referred for assessment of pelvic limb weakness and pain following an acute exacerbation injury approximately four months earlier. The patient had received symptomatic therapy with Carprofen, Gabapentin and Paracetamol, however she continued to show signs of discomfort including a mild left pelvic limb lameness, reduced ability to jump up onto the couch and into the car, and would also regularly yelp and freeze after jumping down.
The pet’s owners also reported that the dog would aggressively chew at her tail base and lumbar spine, resulting in significant hair loss, along with sudden sharp head turning to her lumbosacral region. Diagnostics performed prior to referral included a complete blood cell count and biochemistry, both of which were unremarkable, and orthopaedic radiographs were performed focusing on the cervical spine and thoracic limbs.
Upon referral, due to patient temperament, clinical examination was limited, however a stiff pelvic limb gait was identified with normal pelvic limb reflexes and normal proprioception in all four limbs. No overt orthopaedic disease was identified in the pelvic limbs, however there was a suspicion of lumbar spinal pain based on palpation.
Diagnostic investigation
Based on clinical and historical assessment, contrast enhanced computed tomography (CT) of the entire spine was performed. CT identified marked degenerative lumbosacral disease with severe intervertebral disc protrusion, spondylolisthesis of the L7-S1 articulation, bilateral foraminal stenosis (which was worse on the left) and associated neuritis of the L7 nerve root. The findings from the CT supported a severe case of degenerative lumbosacral stenosis including a dynamic component associated with the subluxation of the L7-S1 articulation resulting in compression of the cauda equina and worsening of the foraminal stenosis. (Figures 1, 2, 3).
Management
Initial management involved epidural administration of 40mg methylprednisolone at the lumbosacral space with radiographic guidance under general anaesthesia1. This treatment carries both therapeutic and diagnostic significance, with resolution of clinical signs allowing exact localisation of the underlying source of pain. Following the initial epidural treatment, there was near complete resolution of clinical signs for approximately four months, before signs such as chewing at the tail base, sharp head turning and general stiffness signs began to return.
At this time, specific surgical intervention was discussed with the pet’s owner, along with the possibility of repeating a second epidural methylprednisolone injection. It is worth noting that repeated epidural injections were not recommended if surgery was a consideration due to the cumulative adhesions that form following each injection. So, the pet owner opted for one more injection aiming for surgical intervention in the coming months.
Approximately four and a half months following the second epidural injection, definitive surgical treatment was undertaken. The aim of surgical treatment in this case was to achieve decompression of the cauda equina and left L7 nerve root, and to restore stability to the lumbosacral articulation. Given the multiple sites of existing nerve root compression, this involved a multi-faceted approach to ensure adequate decompression could be achieved.
A 20ga intravenous catheter was placed in the right cephalic vein and the patient was pre-medicated with 0.2mg/kg Methadone IV. Intravenous fluid therapy was commenced with Lactated Ringer’s Solution at 5mL/kg/hr and maintained throughout the procedure. Induction was performed using Propofol (4mg/kg), and intubation with a size 10 cuffed ET tube. General anaesthesia was maintained using 2% Isoflurane in 100% oxygen, with a constant rate infusion (CRI) of morphine and ketamine running concurrently. Cefazolin (22mg/kg) was administered every 90 minutes throughout anaesthesia.
The patient was positioned in sternal recumbency with the hips flexed in a frog-leg position to allow a dorsal approach to the lumbosacral spine. The 6th and 7th lumbar vertebra and the entire sacrum were exposed to the level of the articular facets and the dorsal intermediate ridge respectively, via elevation of the sacrocaudalis dorsalis medialis muscles bilaterally. The interarcuate ligament at L7-S1 was incised and a dorsal laminectomy was performed across the lumbosacral joint. The laminectomy extended into the caudal one third of the L7 dorsal lamina and the cranial aspect of S1, and was performed using a 4mm round carbide burr and 2mm Kerrison rongeurs.
A left-sided L7-S1 foraminotomy was then performed from a dorsal approach using the carbide burr. The foraminotomy was continued until adequate bone removal was observed with the L7 nerve root no longer appearing impinged by the surrounding osteophyte. Given the flexed position of the lumbosacral joint achieved with patient positioning, only minimal distraction was required using standard Gelpi retractors to ensure complete reduction of the L7-S1 articular facets.
As has recently been reported2, positioning of the patient in a flexed position results in significant flattening of the L7-S1 disc protrusion, therefore often preventing the need for disc fenestration to achieve decompression of the cauda equina. Stabilisation of the lumbosacral joint was achieved with the use of a pedicle screw fixation system (InvetraTM) with placement of pedicle screws bilaterally in L6 (3.5mm x 25mm), L7 (3.5mm x 24mm), S1(5.5mm x 25mm) and S2(4.5mm x 15mm) each connected with a 5.5mm x 120mm titanium connecting rod. (Figure 4, 5, 6).
The surgical site was flushed copiously with sterile saline prior to closure, followed by a routine closure of the lumbar fascia, subcutaneous tissue and skin. Post-operatively the patient was maintained on a morphine/ketamine CRI and administered 0.2mg/kg meloxicam SQ. The patient was continued on Gabapentin 600mg PO BID, Meloxicam 0.1mg/kg PO SID, Paracetamol 15mg/kg BID-TID and Amoxicillin-clavulanic acid 500mg PO BID. The patient was discharged 48 hours post-op with a mild ataxia and kyphosis.
Outcome
Two weeks post-operatively the patient was re-evaluated. The pet’s owner reported near complete resolution of previous clinical signs including tail and lumbar chewing, yelping and sudden head turning. No ataxia or proprioceptive deficits were noted on clinical examination, and the patient was comfortable on lumbosacral palpation.
At the time of writing, the patient continues to remain comfortable and with a significant improvement in her general mobility and will be monitored ongoing.
Lumbosacral distraction and stabilisation can play a significant role in the treatment of degenerative lumbosacral stenosis in dogs, especially in cases where lumbosacral instability is documented.
Appropriate treatment can lead to significant improvements in quality of life for these patients.
References:
1. Janssens, L., Beosier, Y. and Daems, R. 2009, ‘Lumbosacral degenerative stenosis in the dog. The results of epidural infiltration with methylprednisolone acetate: a retrospective study’, Veterinary and Comparative Orthopaedics and Traumatology, vol. 22, no. 6, pp. 486–491. doi:10.3415/VCOT-08-07-0055.
2. Baldo Clemot, I., Briola, C., Ekiri, A.B., Cappello, R., Marinelly, R., Brocal, J., Prodger, A. and Mari, L. 2026, ‘Dynamic magnetic resonance imaging of the lumbosacral spine in neutral and flexed position for presurgical assessment of clinically affected dogs with degenerative lumbosacral stenosis’, Veterinary Surgery, vol. 55, no. 1, pp. 153–164. doi:10.1111/vsu.14311.
Dr Eben Martin
(ECC) FANZCVS (SAS)
Registered Specialist in Small Animal Surgery
Western Australian Veterinary Emergency and Specialty
Dr Eben Martin is a registered specialist in small animal surgery practising at Western Australian Veterinary Emergency and Specialty (WAVES) in Perth.
Following graduation from the University of Melbourne in 2010, Dr Martin obtained Membership in the Emergency and Critical Care Chapter in 2016 with the Australian and New Zealand College of Veterinary Scientists (ANZCVS), followed by Membership in the Small Animal Surgery Chapter in 2018.
Following completion of a surgical residency at WAVES, he was awarded Fellowship of the ANZCVS in Small Animal Surgery in 2023. Dr Martin has a strong passion for neurosurgery and orthopaedic surgery.
