Clinical Observation Of The Mid-term Effect Of Percutaneous Transpedicular Lag-screw Fixation For Hangman Fracture

Objective:To observe the mid-term effect of percutaneous transpedicular lag-screw fixation for Hangman fracture.Methods:23 patients with Hangman fracture who received percutaneous transpedicular lag-screw fixation in The First Affiliated Hospital of Soochow University from January 2015 to June 2018 were analyzed retrospectively,including 17 males and 6 females,aged from 25 to 82 years(mean 48.1±16.8)years.After admission,the patients improved the imaging examination,measured and recorded the degree of axis angulation,the distance of axis displacement and the height of C2-3 intervertebral space,and classified the patients according to the Levine-Edwards classification.The injury mechanism,preoperative symptoms,operation time,intraoperative blood loss and postoperative recovery were recorded,and the cervical dysfunction index(NDI index)and visual analogue scale(VAS score)were used as reference indexes to evaluate the curative effect of this operation.The fracture healing was observed by imaging examination after operation,3 months,12 months and the last follow-up.At the same time,the degree of axial angulation,the distance of axial displacement,the height of C2-3 intervertebral space and the range of hyperextension and flexion of cervical spine were measured and analyzed,and the cervical function was comprehensively evaluated in order to observe the medium-term clinical effect of this operation.Results:8 cases of type ? Hangman fracture,10 cases of type ? Hangman fracture and 5 cases of type ? A Hangman fracture were included in this study.The effective follow-up time was 18-58 months,and the average follow-up time was(30.3±11.2)months.The operation time of all patients was 55-110 min,with an average of(80.8±14.2)min.The average intraoperative blood loss was 5-40 ml,and the average blood loss was(13.7±8.6)ml.There were 22 cases of bilateral screw placement and 1 case of unilateral screw placement.All the 45 screws were in good position.There were no important tissue injuries such as spinal cord,nerve and blood vessels during the operation.The incisions healed well after operation,and no postoperative complications such as infection and cerebrospinal fluid leak occurred.All patients achieved bony union at the last follow-up,no delayed union or malunion,no failure of screw fixation or re-displacement of the fracture.The postoperative VAS score decreased from(6.5±1.0)to(2.8±0.6)and the NDI index at the last follow-up decreased from(78.9±6.0)to(49.6±6.1).There were significant differences between the two indexes at the last follow-up(P<0.001).According to the results of the imaging examination,the angular angle of axis recovered from(8.0 ± 1.1)° to(2.0 ±0.8)°,the distance of axis displacement decreased from(3.6±1.1)mm to(1.4±0.7)mm.The height of C2-3 intervertebral space before operation was(6.2 ± 1.7)mm,which recovered to(7.5±0.7)mm after operation,and there was no significant change at the last follow-up(P<0.001).The range of motion of cervical hyperextension and flexion was(42.9±4.5)° after operation and(60.4±4.7)°at the last follow-up.The range of motion of cervical vertebra was significantly improved(P<0.05).Conclusion:Minimally invasive treatment of Hangman fracture with percutaneous transpedicular lag-screw has the advantages of short operation time,less trauma and quick recovery.Under the premise of accurate and safe placement of screws,this method can immediately reduce the fracture,promote fracture healing,and maintain good cervical stability and range of motion during the mid-term follow-up,so it can become a new choice for the treatment of Hangman fracture.