Objective To investigate the use of sodium hyaluronate and the preservation of epidural fat in the prevention of epidural scar adhesion after microendoscopic discectomy (MED). Methods A total of 300 patients receiving MED from July 2000 to October 2001 were randomly divided into 2 groups: patients in group A were given sodium hyaluronate with the preservation of epidural fat, while those in group B were on the contrary. Results The mean follow-up duration was 42 months in the group A and 44 months in the group B, respectively. The rate of excellent or good results was 98.6% in the group A (144/146), while 93.8% in the group B (135/144) ( ? 2=4.731, P =0.030). Postoperatively, the pain reappeared in 4 cases in the group A and in 6 cases in the group B, respectively, in which a re-operation was required. Re-operations found the epidural scar adhesion was grade 0 (3 cases) and grade 1 (1 case) in the group A, and grade 2 (2 cases) and grade 3 (4 cases) in the group B ( P =0.005). Conclusions Use of sodium hyaluronate with the preservation of epidural fat can improve the efficacy of MED and effectively prevent epidural scar adhesion.

Objective To explore clinical results of posterior spinal approach microendoscopic disectomy(MED) for the treatment of lumbar disc herniation in adolescents.Methods A total of 25 consecutive patients treated by MED from February 2000 to August 2004 in this hospital were analyzed retrospectively.Clinical results were assessed with the modified Macnab criterion.Pre-and post-operative symptoms and functional states were evaluated by the Chinese version Oswestry Disability Index(ODI).Results A conversion to open procedure was required in 1 patient.The operating time was 35～65 minutes(mean,44.8?9.0 minutes);the estimated blood loss during operation was 30～80 ml(mean,51.3?14.6 ml);the postoperative hospital stay was 6～10 days(mean,7.5?1.0 days).All incisions healed by first intention.There were no dural tears,nerve root injuries,intervertebral space infections,or great vessel injuries.Twentg-two patients were followed for 7～57 months(mean,33.4?17.8 months).There were significant differences between preoperative ODI(46.2%?8.5%) and postoperative ODI(1.8%?3.0%).The improvement rate of ODI was 44.4%?9.2%(t=21.61,P=0.00).Clinical results assessment by the modified Macnab criterion revealed "excellent" in 19 patients and "good" in 3 patients,the rate of excellent or good results being 100%. Conclusions Microendoscopic disectomy can be performed safely and effectively for lumbar disc herniation in adolescents,resulting in little trauma,fast recovery,and excellent clinical results.

Objective To design a new type of posterior lumbar interbody fusion cage made of NiTi shape-memory alloy and to evaluate its histological and biomechanical behavior through animal study. Methods This study contained three steps of experiments which was posterior lumbar interbody fusion using different fusion materials and devices. At the first step, 12 sheep lumbar functional spinal units were randomly divided into 4 groups with 3 specimens in each group. There was one group with autogenous iliac crest bone dowel(IG), one group with interfix lumbar cage(cage), one group with NiTi-TFC(NT) and one group served as control group. Nondestructive biomechanical tests were carried out for each group. At the second step, 15 sheep were randomly divided into three groups with 5 specimens in each group. There was one group with cage and autogenous iliac crest graft, one group with NT and iliac crest and one group served as control group. All the animals were undergone imaging study regularly to evaluate the change of the intervertebral space heights and the process of fusion. At the third step, all animal from the second step were sacrificed 6 months later for histological analysis of the operated segments. All the data were statistically analyzed using SPSS 7.0. Results The strength and axial stiffness of the autogenous iliac crest bone dowel graft group and the control group were significantly different from the NT and cage group(P

[Objective]To evaluate short term clinic results of prosthetic disc nucleus(PDN)replacement for the treatment of lumbar disc herniation.[Method]Twenty cases of lumbar disc herniation(including one case of recurrent lumbar disc herniation)were treated with PDN from June 2003 to November 2003,including 13 males and 7 females with average age of 40.5 years.All cases were implanted with a single PDN,in which 7 cases with PR725,8 cases with PW725,and 5 cases with PDN-SOLO-7 respectively.[Result]After surgery,one patient accepted the revision operation to remove the PDN because of device migration,the others experienced pain relief.The nineteen cases were followed-up for 23～29 months(mean 26.4 months).Compared with preoperative height of intervertebral disc,it gained increase of 17.2%(P

Objective To investigate clinical features and anterior surgical results of cervical myelopathy in patients more than 70 years of age. Methods Twenty aged patients with cervical myelopathy who underwent anterior decompression with bone graft surgery were reviewed. Neurological function was assessed using a scoring system proposed by the Japanese Orthopaedic Association (JOA score). The clinical results and complications were compared with the control group which included 31 patients with multisegmental cervical myelopathy and less than 69 years old and underwent the same operation. Results The preoperative mean JOA score was 9.3 (ranged from 3 to 14) and the JOA score at latest follow-up averaged 13.4 (ranged from 8 to 17) in the aged patient group. 68 percent patients had achieved an excellent or good result and the recovery rate was 58%. 71 percent patients had achieved an excellent or good result and the recovery rate was 67% in the control group. No statistical difference was found in the excellent and good result rate or the recovery rate of JOA score between the aged group and the control group (?字2=0.04, P=0.85;t=1.12, P=0.138). The incidence of surgical related complications in the aged group was 35% (7 cases), which was considerably higher than that in the control group (3 cases, 10%) but without statistical difference (?字2=3.47, P=0.06). In the preoperative flexion-extension stress lateral radiographs, the incidence of cervical instability was higher in the control group (8 cases, 26%) than that in the aged group(1 case, 5%). Conclusion 1) Multilevel lesion induced by overcompensation for cervical instability are the probable cause of myelopathy in aged patients. 2) Anterior decompression is beneficial to improve the neurological function and life style in the aged patients with cervical myelopathy, but associated with a high incidence of surgical complications.