Objective To investigate the clinical effects of pars repair by the pedicle screws,laminal hooks and auto iliac bone graft through the Wiltse approach via Quadrant channel for the treatment of the adolescent spodylolysis.Methods From November 2007 to April 2011,pars defects of 11 patients (10 males and 1 female) were repaired with pedicle screws,laminal hooks and auto iliac bone graft via Quadrant channel through the Wiltse approach.The mean age of 11 patients was 17.3 years (range 15-19).Mean course was 9.9 months (range 6-14 months).All patients have bilateral pars defect of L5.There was no poroma across the pars that have been proved by X-ray film and 3-D CT before the operation.There were 4 patients with Ⅰ grade spondylolisthesis.The degeneration of the intervertebral disc assessed by Pfirrmann grade of all patients was no more than Ⅰ grade.Visual analogue scale (VAS) and Oswestry disability index (ODI) were compared before and after operation.The fusion of pars defect was observed by X-ray film and 3-D CT.Results The mean operation time was 85.5±12.3 min (range 70-110 min); intraoperatve blood loss was 80-150 ml (mean 105 ± 19.4 ml).Two patients were lost in follow-up after operation and the others had been followed up for 12 to 24 months (mean 16 months).All patients had significant pain relief and function recovery after operation.Mean postoperative VAS score was 1.5± 1.0 compared with 4.5± 1.0 of preoperation (t=4.603,P=0.002).ODI was decreased from 49.3％± 14.2％ of preoperation to 12.0％±4.9％ of the last follow-up (t=7.344,P=0.000).With the Macnab grades,7 patients are excellent,2 patients are good.3-D CT showed that all pars defect were fused in the last follow-up.Conclusion Pars repair by the pedicle screws,laminal hooks and auto iliac bone graft through the Wiltse approach via Quadrant channel can protect the paravertebral muscle,relief patients from pain,and improve function.

Objective To compare the surgical effects between minimally invasive anterior ondontoid screw fixation assisted by our self-designed odontoid guider and open anterior ondontoid screw fixation in the treatment of odontoid fractures of Anderson-D'Alonzo type Ⅱ.Methods From July 2011 to July 2016,28 adults with odontoid fracture of Anderson-D'Alonzo type Ⅱ were treated at Department Ⅱ of Spinal Surgery,Hospital of 89 Army Group of Chinese PLA.Of them,15 were treated by minimally invasive anterior ondontoid screw fixation assisted by our self-designed odontoid guider (guider group) while the other 13 by open anterior ondontoid screw fixation (open group).All the patients were male,aged from 31 to 59 years (average,42.7 years).The 2 groups were compared in terms of incision length,operation time,intraoperative bleeding,intraoperative fluoroscopic frequency and hospital stay.Results There were no significant differences between the 2 groups of patients in their preoperative general data,indicating they were compatible (P ＞ 0.05).All the patients were followed up for 12 to 45 months (average,22.1 months).The internal fixation was in good place and clinical union achieved in all the 28 patients.The incision length (2.2 ± 0.1 cm),operation time (45.0 ± 3.1 min),intraoperative bleeding (29.0 ± 2.3 mL) and intraoperative fluoroscopic frequency (15.5 ± 1.9 times) for the guider group were all significantly less than those (2.9 ±0.7 cm,61.6±3.8 min,51.6±3.9 mL and 21.7±3.2 times,respectively) for the open group (P ＜0.05),but there was no significant difference between the 2 groups in hospital stay (6.5 ± 0.5 d versus 6.5 ± 0.6 d) (P ＞ 0.05).Conclusion In the treatment of odontoid fractures of Anderson-D'Alonzo type Ⅱ,compared with open anterior ondontoid screw fixation,the minimally invasive anterior ondontoid screw fixation assisted by our self-designed odontoid guider may lead to a smaller incision,shorter operation time,less blood loss and a lower fluoroscopic frequency.