Objective To investigate the methods and clinical outcome of the operative treatment of thoracolumbar fractures with pedicle screw single segment fixation and the approach through paravertebral muscles.Methods One hundred and twenty patients were selected as our subjects,who were suffered from thoracolumbar fracture without neurological deficit and underwent surgical treatment in the Central Hospital of Zibo from Jan.2009 to Dec.2010.All cases were randomly divided into mini-invasion group and control group.Patients in mini-invasion group were received the single segment fixation of the spatium intermusculare of longissimus muscle and multifidus,and in control group were received the traditional approach with short segment fixation group.The muscle gap approach along the longest muscle and multifidus muscle gap enters,preserving the integrity of the paraspinal muscles.Results The operation periods of mini-invasion group and control group were (53.8 ± 12.3) min and (88.5 ± 18.5) min (t =1.731,P ＜ 0.05),the intraoperative bleeding volume were (95.7 ±21.5) ml and (280.3 ±83.1) ml(t =2.414,P ＜0.05),the postoperative drainage volume were (20.4±8.2) ml and (132.9 ±50.3) ml(t =2.068,P ＜0.05) and inpatient time were (13.8 ±2.2)d and (20.4 ±5.5)d(t =1.853,P ＜0.05).However,there was no significant difference in terms of fracture healing time,visual analogue scale,Oswestry disability index and radiology(P ＞0.05).All cases had union of fractures and no reduction loss and fixation failure occurred.Condusion The treatment of pedicle screw single segment fixation and the approach through paravertebral muscles on thoracolumbar fracture is proved to be an effective method with minimally invasive,less bleeding volume,simple procedure and fast recovery method.

This is an in vitro study to explore the effects of cryopreservation and resuscitation on the biological characteristics of osteoblasts at different times. Osteoblasts taken from the crania of newly born SD rats were cultured. Comparative studies were made on the cells' proliferation, the activity of alkaline phosphatase (ALP), and the number of live cells among fresh cultured osteoblasts and cells after the inception of cryopreservation and resuscitation at time-periods of one, three, six months respectively. The results showed that there were no significant differences among four groups in cell proliferation and in activity of ALP (P > 0.05). Yet, after cryopreservation and resuscitation, there were significant differences between the six-month group and the other three groups (P < 0.05). The results also showed, after cryopreservation and resuscitation, there were no significant differences between the control group and the one-month and three-month groups, respectively (P > 0.05). These findings indicated that the live cells might decrease in number after the osteoblasts were cryopreserved for too long a period, but after cryopreservation and resuscitation, the cells still retained the original biological characteristics of osteoblasts.
Alkaline Phosphatase ; metabolism ; Animals ; Animals, Newborn ; Cell Proliferation ; Cells, Cultured ; Cryopreservation ; methods ; Osteoblasts ; cytology ; Rats ; Rats, Sprague-Dawley ; Skull ; cytology ; Time Factors ; Tissue Engineering ; methods