RESUMEN
Objective: To develop and evaluate the safety and accuracy of an open, end-on fluoroscopic guided (EOFG) drill hole position technique in canine cadaveric spinal surgery, in comparison to a traditional free-hand (FH) drilling technique. Study design: Cadaveric comparison study. Animals: Canine cadaveric vertebral columns (n = 4). Methods: Computed tomography (CT) scans were performed for in-silico planning. Ideal implant purchase depth and angulations were determined from previously published data. Plans for end-on fluoroscopic guided drill holes included angled reconstructions in thick slab mode to mimic fluoroscopic images. Following surgical preparation of T8 to S2, holes were drilled by one of two experienced surgeons randomized evenly by operated side, surgeon, and technique. C-arm fluoroscopy was utilized for the end-on technique. CT was repeated after the procedures. Safety was determined categorically using a modified Zdichavsky classification and "optimal" placement was compared between techniques. Continuous data for drill-hole accuracy was calculated as angle and depth deviations from the planned trajectories. Data sets were analyzed at both univariable and multivariable levels with logistic regression analysis. Results: Drill hole safety was categorized as optimal (modified Zdichavsky classification 1) in 51/60 (85%) of drill holes using EOFG and 33/60 (55%) using FH (P < 0.001) techniques. There were no "unsafe" holes (modified Zdichavsky classification 3a). Optimal drill hole placement was significantly associated with the EOFG technique and use of the largest cadaver, and was significantly less likely within the thoracic region. Mean angle and depth deviations were significantly lower with the EOFG technique. Angle deviations were significantly lower for EOFG in the lumbar region, whereas bone purchase deviations were significantly lower for EOFG in both the thoracic and lumbar regions. The mean time taken to drill the hole was significantly longer for the EOFG technique. Conclusion: Optimal drill hole placement was significantly more likely with the EOFG technique and improved the accuracy of bone purchase in the thoracic region. Clinical significance: The EOFG technique shows promise for translation into a clinically setting, potentially improving implant purchase and therefore stabilizing construct strength, whilst potentially reducing the likelihood of neurovascular injury and need for surgical revision.
RESUMEN
BACKGROUND: The Basset Hound is the largest chondrodystrophic breed predisposed to thoracolumbar intervertebral disc extrusion (TL-IVDE). However, literature describing this particular breed in terms of incidence, signalment, anatomical location, clinical severity and short-term outcome of TL-IVDE is lacking. METHODS: The medical histories of Dachshunds and Basset Hounds presenting to three neurology departments were retrospectively assessed. Information collected for each dog included signalment, whether it had received a diagnosis of TL-IVDE, duration of clinical signs, affected discs and anatomical region and neurological grading at presentation and discharge. RESULTS: A total of 270 Dachshunds and 188 Basset Hounds were included for incidence analysis. Of these, 154 Dachshunds and 68 Basset Hounds with confirmed TL-IVDE were included for signalment, anatomical location, clinical severity and short-term outcome analysis. Statistical analysis indicated a significantly higher incidence of TL-IVDE in Dachshunds than in Basset Hounds (77.4% vs. 36.2%, p < 0.05). Basset Hounds presenting to a neurology department were older (median 87.5 months vs. 66.5 months), had a greater proportion of midlumbar IVDE (L2-L5) and were more frequently ambulatory at discharge than Dachshunds. Only one Basset Hound presented as paraplegic without nociception, compared with 16 Dachshunds (1.5% vs. 10.4%). LIMITATIONS: The study had a retrospective design and included multicentric non-standardised cases. CONCLUSION: TL-IVDE incidence was higher in Dachshunds than in Basset Hounds. Basset Hounds were older at presentation, frequently affected more caudally in the vertebral column and more frequently ambulatory at discharge than Dachshunds. The differences found in this study could aid in the development of preventive strategies.