Mark Ren, Barry R. Bryant, Andrew B. Harris, Khaled M. Kebaish, Lee H. Riley III, David B. Cohen, Richard L. Skolasky and Brian J. Neuman
The objectives of the study were to determine, among patients with adult spinal deformity (ASD), the following: 1) how preoperative opioid use, dose, and duration of use are associated with long-term opioid use and dose; 2) how preoperative opioid use is associated with rates of postoperative use from 6 weeks to 2 years; and 3) how postoperative opioid use at 6 months and 1 year is associated with use at 2 years.
Using a single-center, longitudinally maintained registry, the authors identified 87 patients who underwent ASD surgery from 2013 to 2017. Fifty-nine patients reported preoperative opioid use (37 high-dose [≥ 90 morphine milligram equivalents daily] and 22 low-dose use). The duration of preoperative use was long-term (≥ 6 months) for 44 patients and short-term for 15. The authors evaluated postoperative opioid use at 6 weeks, 3 months, 6 months, 1 year, and 2 years after surgery. Multivariate logistic regression was used to determine associations of preoperative opioid use, dose, and duration with use at each time point (alpha = 0.05).
The following preoperative factors were associated with opioid use 2 years postoperatively: any opioid use (adjusted odds ratio [aOR] 14, 95% CI 2.5–82), high-dose use (aOR 7.3, 95% CI 1.1–48), and long-term use (aOR 17, 95% CI 2.2–123). All patients who reported high-dose opioid use at the 2-year follow-up examination had also reported preoperative opioid use. Preoperative high-dose use (aOR 247, 95% CI 5.8–10,546) but not long-term use (aOR 4.0, 95% CI 0.18–91) was associated with high-dose use at the 2-year follow-up visit. Compared with patients who reported no preoperative use, those who reported preoperative opioid use had higher rates of use at each postoperative time point (from 94% vs 62% at 6 weeks to 54% vs 7.1% at 2 years) (all p < 0.001). Opioid use at 2 years was independently associated with use at 1 year (aOR 33, 95% CI 6.8–261) but not at 6 months (aOR 4.3, 95% CI 0.95–24).
Patients’ preoperative opioid use, dose, and duration of use are associated with long-term use after ASD surgery, and a high preoperative dose is also associated with high-dose opioid use at the 2-year follow-up visit. Patients using opioids 1 year after ASD surgery may be at risk for long-term use.
Michael K.-Y. Hong, Matthew K.-H. Hong, Wei-Ren Pan, David Wallace, Mark W. Ashton and G. Ian Taylor
The angiosome concept has been the subject of extensive research by the senior author (G.I.T.), but its specific applicability to the spinal cord was hitherto unknown. The aim of this study was to see if the spinal cord vasculature followed the angiosome concept and to review the usefulness of preoperative spinal angiography in surgery for spinal disorders. Spinal cord infarction and permanent paraplegia may result from inadvertent interruption of the artery of Adamkiewicz. Spinal angiography, which may enable avoidance of this catastrophic complication, is still not commonly used.
Two fresh cadavers were injected with a gelatin–lead oxide mixture for detailed comparative study of spinal cord vasculature. One cadaver had insignificant vascular disease, whereas the other had extensive aortic atherosclerosis, presenting a unique opportunity for study. After removal from each cadaver, radiographs of the spinal cords were obtained, then photographed, and the vascular territories of the cords were defined.
Four angiosome territories were defined: vertebral, subclavian, posterior intercostal, and lumbar. These vascular territories were joined longitudinally by true anastomotic channels along the anterior and posterior spinal cord. Anastomosis between the anterior and posterior vasculature was poor in the thoracolumbar region. The anterior cord relied on fewer feeder arteries than the posterior, and the anterior thoracolumbar cord depended on the artery of Adamkiewicz for its supply. In chronic aortic disease with intercostal artery occlusion at multiple levels, a rich collateral circulation supporting the spinal cord was found.
The arterial supply of the spinal cord follows the angiosome concept. The atherosclerotic specimen supports the suggestion that the blood supply is able to adapt to gradual vascular occlusion through development of a collateral circulation. Nevertheless, the spinal cord is susceptible to ischemia when faced with acute vascular occlusion. This includes inadvertent interruption of the artery of Adamkiewicz. The authors recommend the use of preoperative spinal angiography to prevent possible paraplegia in removal of thoracolumbar spinal tumors.