The effect of acute smoking on spinal fusion: an experimental study among rabbits.
BACKGROUND
The establishment of an environment to force animals to inspire cigarette smoke is mandatory to study the true effects of smoking. This model has been used to study long-bone healing but has not yet been used to study spinal fusion.


METHODS
Forty male rabbits were divided into four equal groups. All the animals underwent bilateral intertransverse-process fusion at L5-L6 using the 1995 fusion model of Boden et al. The first (C8-week) group did not undergo cigarette smoke inhalation and individual rabbits were killed at 8 weeks; the second (S8-week) group underwent intermittent cigarette smoke inhalation and individual rabbits were killed at 8 weeks; the third (C6-week) group did not undergo cigarette smoke inhalation, and animals were killed at 6 weeks; and the fourth (S6-week) group underwent intermittent smoke inhalation and group-included rabbits were killed at 6 weeks. Subsequent to the animals having been killed, the fusion masses were harvested for a series of studies including manual palpation, biomechanical testing, radiographic examination, and histologic analysis.


RESULTS
Six rabbits died shortly after the operation. Of the remaining 34 rabbits, the lumbar spine specimen was harvested for study. Manual palpation, radiographic examination, and histologic analysis of the fusion masses revealed no statistically significant difference in fusion results between the control and the corresponding smoking group killed at either 8 weeks or 6 weeks. Biomechanical testing of the fusion masses also revealed no statistically significant difference in fusion results between the control and the smoking group killed at 8 weeks, although it did indicate that smoking resulted in a 44% decrease in mean flexion stiffness and a 32% decrease in mean extension stiffness among the animals killed at 6 weeks. The former (decrease in flexion stiffness) was statistically significant (p < 0.05).


CONCLUSIONS
The results of the biomechanical testing conducted as a part of the current study demonstrate that acute cigarette smoke inhalation delays but does not prevent the spinal fusion process for rabbits.
Lee
Tao-Chen
TC
Departments of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China. leetc@adm.cgmh.org.tw
Ueng
Steve Wen-Neng
SW
Chen
Hsiang-Ho
HH
Lu
Kang
K
Huang
Hsiu-Yu
HY
Liliang
Po-Chou
PC
Su
Thung-Ming
TM
Yang
Lin-Cheng
LC
D000818:Animals; D001696:Biomechanical Phenomena; D008159:Lumbar Vertebrae / Q000293:injuries; D008297:Male; D023421:Models, Animal; D011817:Rabbits; D012907:Smoking / Q000503:physiopathology*; D013123:Spinal Fusion; D013124:Spinal Injuries / Q000503:physiopathology* / Q000601:surgery*; D013997:Time Factors; D014945:Wound Healing