Biomechanical study and preliminary clinical outcome for unstable Jefferson fractures by transoral JeRP internal fixation

English Keywords:Jefferson fracture  Atlas  Jefferson fracture reduction plate  Unstable  Transoral

English Abstract:

  【Abstract】 Objectives: To evaluate the biomechanical and preliminary clinical outcome for unstable Jefferson fractures by Jefferson fracture reduction plate(JeRP) internal fixation. Methods: (1)A total of 6 human cadaveric upper-cervical specimen were collected in Zhengzhou Orthopaedics Hospital from May 2012 to March 2014 and made into one type of unstable Jefferson fractures, and then fixed with JeRP. The ranges of motion(ROM) of C0-3 in 3 positions were measured by three-dimensional spinal motions, and the neutral zones and ROMs of every dimension in every position were analyzed. The load on the specimen was 20N in the flexion-extension and lateral-bending direction, 2.0N·m axial torque in rotation test. (2)8 patients diagnosed as unstable Jefferson fracture and operated in Guangzhou General Hospital of Guangzhou Military Command from April 2008 to January 2014 were collected, including 6 males and 2 females， with age ranging from 29 to 67 years(average, 39 years)． 5 cases of them had 3 fractures while the other 3 cases had 2 fractures in the anterior arch and posterior arch respectively. None of these patients got rupture of transverse ligament of atlas. All the 8 patients′ main presentations included neck pain and limitation of motion. 7 cases of them had neurological deficit while 1 case got spinal cord injury and were graded as grade D by Frankel grading system. All the 8 patients underwent transoral reduction and fixation surgery with JeRP. During periodic postoperative follow-up, CT and cervical hyperextension- hyperflexion X-rays were performed to observe the healing process and stability of atlantoaxial segment. Results: (1)There was significant difference between the neutral zone of upper cervical spines of fracture status and that of normal status（P<0.05）. There was no significant difference between the neutral zone of upper cervical spines of fixation status and that of normal status（P>0.05）. There was no significant difference between the ROM of upper cervical spines of fixation status and that of normal status（P>0.05）. (2)All patients had completed follow-ups of 6-15 months(average, 7.2 months)． All these patients′ neck pain got relief and the patient suffering from neurological deficit got Frankel grade improved form grade D preoperatively to grade E postoperatively. All the patients′ oral incision healed with no infection. All fractures were reduced and healed with no atlantoaxial instability or limitation of motion. The incipient clinical results were satisfactory. Conclusions: JeRP fixation can both reduce unstable Jefferson fractures anatomically and preserve the activity of upper-cervical segment. It is a valid technique for the fusion of upper cervical spine.