Objective To discuss the application of Apofix interlaminar clamp for the treatment of atlantoaxial instability. Methods From April 2000 to July 2004, 30 patients with atlantoaxial instability were treated with posterior atlantoaxial fusion and Apofix fixation. There were 24 males and 6 females. The mean age of the patients was 41 years (range, 19 to 67 years). The patients included 5 with atlantoaxial dislocation, 25 with odontoid fracture (including fresh fracture for 21, old fracture and nonunion for 4; Anderson Ⅱ for 23 and Anderson Ⅲ for 2). After reducted by skull traction, atlanto-occipital space, arcus posterior atlantis and axial laminar were exposed during operation, upper and lower hooks were inserted. The iliac bone graft was inserted into the space of C1 and C2, the connecting rod of the clamp was compressed and fixed. Results The follow-up of all cases ranged from 8 months to 3 years and 10 months (with the mean of 27 months). There were 28 cases with complete reduction of fracture and dislocation, 2 cases in incomplete reduction. The operation time was 70 to 150 minutes, and the average blood loss was 65 ml. Patients could sit up 3 days (2 to 6 days) after surgery with soft collar. The mean off-bed time was 7 days (2 to 10 days) after operation in the patients without or less spinal cord injury. All cases obtained solid bony fusion 3 months postoperatively. No severe complications such as injuries of vertebral artery, nerve root and spinal cord or aggravation of spinal cord injury occurred. Conclusion Apofix interlaminar clamp has advantages of convenience in operation, provided reliable and safe stability for atlatoaxial segment. The results suggested that this technique is an efficient, reliable segmental posterior fixation.

Objective To discuss the application of cervical lateral mass plate for the treatment of fractures and dislocations of the cervical spine. Methods From January 1998 to January 2001, internal fixation with cervical lateral mass plate and bony fusion were performed in 21 patients during posterior decompression for the treatment of fractures and dislocations of the lower cervical spine . A posterior median approach was used to expose the lateral edge of the articular process. All patients received spinal decompression and reduction according to the types of fracture and dislocation. A cervical lateral mass plate was applied in each lateral mass, a suitable bicortical screw was inserted using Magerl technique (the inserting point of the screw was 2 mm medial and superior to the center of lateral mass, the direction was 20?-25? laterally and 30?-40? cranially). Results The follow-up of all 21 cases ranged from 9 months to 3 years and 9 months (with the mean of 27 months). There were 20 cases with complete reduction of antero-posterior and rotational dislocation, and 1 case with incomplete reduction according to post-operative X-ray film. Patients could sit up with the protection by wearing soft collar 4 days (2-7 days) after the surgery. The mean off-bed time of those without spinal cord injuries or with spinal cord injuries less than Frankel C grade were 9 days (3-14 days) after operation. All cases obtained solid bony fusion 6 months postoperatively. Eighteen cases with spinal cord injury improved one ASIA grade, 2 cases without root injury obtained complete recovery eventually. No severe complications such as injuries of vertebral artery, nerve root and spinal cord or aggravation of spinal cord injury occurred. Conclusion Cervical lateral mass plate fixation has the advantages of wide indications, strong stability, short segment fixation and easily reduction. The results suggested that this technique is an efficient, reliable segmental posterior fixation.

[Objective] To evaluate the therapeutic effect of early composite treatment in patients with cervical spinal cord injury(SCI) caused by diving injury.[Method]27 patients of SCI caused by diving injury,including complete SCI in 15 patients and incomplete SCI in 12 patients,were analyzed.Early composite treatment scheme were as follows:(1) systemic treatment: respiratory support and effective circulation volume for maintenance of systolic pressure more than 90mmHg and oxygen saturation more than 90%.(2) Early pharmacological treatment such as methylprednisolone and dexamethasone.(3) Immobilization and reduction of the injured cervical spine by skull traction.(4) Early cervical decompression,reduction,graft and internal fixation.(5) Early hyperbaric oxygen therapy after operation.The stability and fusion of the injured segments and the complications of the hardware were observed on the X-ray film postoperatively.The spinal cord function was evaluated with ASIA grades and sensorymotor scores.[Result]All 27 patients were followed up for 12 to 36 months,with an average of 28 months.No intra-operative and post-operative complications,the incision healed well.The injured segments were stable and all bone grafts acquired fusion in 3 months,no plates or screws broken or loosen.The neurological recovery were detected in 13 patients.The neurological recovery rate was 20% in complete SCI,83.3% in incomplete SCI,48.1% in the total.The ASIA grades of the sensory and motor scores could hardly be improved postoperatively in complete spinal cord injury while in incomplete spinal cord injury the ASIA grades and sensorymotor scores increased significantly.[Conclusion]Early composite treatment of cervical spinal cord injury caused by diving injury can significantly improve neurological function of the cervical spinalcord injury patients.

Objective To review the clinical results of percutaneous laser disc decompression(PLDD)in the treatment of cervical disc herniation.Methods PLDD was adopted in the treatment of cer-vi cal disc herniation in32patients.There were19males and13females with an average age of 54years,ranging from33to67years.The lesions were located at the levels of C 3,4 in4cases,C 4,5 in11cases,C 5,6 in13cases and C 6,7 in7cases.The laser fiber was introduced into the herniated disc space with the needle puncturing percu taneously in anterior surface of neck under fluoroscopic guidance.The ND:YAG laser was of 1060nm wave-length,and the diameter of the fiber was400?m.The laser output power was15w with1s emission and5s interval.The compression of spinal cord and surrounding tissue was eliminated by reducing the intra-disc pressure through the vaporization of the disc nucleus.The total laser output power was decid ed depending on the age of the patients,degenerative degree of the disc and the reactive process of heat.The total powers of the group were360J to1100J.Results The mean follow-up was8months,ranging from3to15months.The clinical evaluations were classified as excellent in16cases(50%),good8cases(25%),fair4cases(12.5%)and poor 4cases(12.5%).The general effective ratio was87.5%,the ex cellent and good ratio was75%.The remission ratio of the symptoms was80.7%for the neck and shoulder pain,84.2%for ra-diating pain of the nerve roots of upper extremities,60%for symptoms of the lower ex tremities and78.5%for cervi cal dizziness.No complications occured.Conclusion PLDD could relieve the symptoms and signs of patients cervical disc herniaton.PLDD is easy to manipulate,safe,mini-invasive,and the patients recov-ered sooner with less complications.

Objective To discuss the CT value measurement of the soft tissue such as sludged blood,gel foam and residual nucleus in vertebral canal at the early stage after lumbar discectomy.Methods 40 patients of lumbar disc herniation were divided into gel foam group and sludged blood group randomly.There were 22 males,18 females,with the mean age 50.6 years(ranged from 25 to 75 years).All patients underwent lumbar CT scan before operation and CT values of herniated nucleus were measured(simulating residual nucleus after operation).Same surgeon group performed posterior approach discectomy through open window in the vertebral plate.A long column roll of gel foam was placed epidurally at the site where nucleus were take out to stop bleeding in gel foam group.While in sludged blood group just douched with saline.All patients underwent lumbar CT scan one week after operation and CT values of the soft tissue in vertebral canal measured.The CT values before and after operation and between groups were compared and analyzed.Results CT values of the herniated disc of 40 patients were 43.70-66.70 HU.CT values of the soft tissue in vertebral canal of 20 patients gel foam group were(23.00?3.36)HU.Paired-samples t test of the values of herniated nucleus before operation and the gel foam showed t=12.32,P=0.00,with statistic significance.CT values of the soft tissue in vertebral canal of sludged blood group were(25.60?6.75)HU.Paired-samples t test of the values of nucleus before operation and sludged blood showed t=13.84,P=0.00,with statistic significance.Independent-samples t test of values of gel foam group and sludged blood group showed t=-0.78,P=0.46.No significant differences existed.Conclusion CT value measurement is valuable to distinguish the nature of the soft tissue in vertebral canal in clinical use.

[Objective]To evaluate temporary balloon occlusion of the abdominal aorta in sacral tumors surgical operation as a useful adjuvant technique.[Method]Temporary balloon occlusion of abdominal aorta was used in 36 patients during the sacral tumors surgical operations(study group).Another 32 patients with sacral tumors who receive the preoperative arterial embolization theraphy were used as control group.The quantity of blood loss during the surgery,the whole surgery time,the complication,mean days in hospital,recovery days post-operation and recurrence rate were recorded.The results in two groups were compared with each other.[Result]The time of operations of study group was(149.19?73.81)minutes.The loss of blood was(826.67?509.11)ml.Two cases had complication after operation.Mean days in hospital were(26.05?7.08)d.Recovery days post-operation were(34.61? 8.22)d.Recurrence rate of six months was 5.5 %.Recurrence rate of one year was 11%.Recurrence rate of two years was 16%.The time of operations of control group was(221.33?45.19)min.The loss of blood was( 1 652 ?706.99)ml.Eight cases had complications after operation.Mean days in hospital were(37.93?7.63)d.Recovery days post-operation were(46.03?9.67)d.Recurrence rate of six months was 18%.Recurrence rate of one year was 31%.Recurrence rate of two years was 40.6%.[Conclusion]The effect of temporary balloon occlusion of abdominal aorta is reliable.It significantly reduced the time of operations,the loss of blood,complications,mean days in hospital,recovery days post-operation and recurrence rate.It makes the operation of sacral tumors much more safer than before.

Objective To explore the value of combining Uniplate anterior cervical plate system with titanium cage to treat single level cervical spondylotic myelopathy. Method Observing the clinical outcome and X-ray results of 32 patients with cervical spondylotic myelopathy undergone anterior decompression, autograft fusion and internal fixation with Uniplate anterior cervical plate system and titanium cage. Results All patients were followed up for 3 to 12 months. According to bony fusion criteria,no implants breakage, dislocation or loosening was found in all cases in 3 months' postoperatively radiological review. According to Odom classification,excellent outcome was 27 patients, good was 5 patients, the excellent and good rate was 100%(32/32). Conclusions Combining Uniplate anterior cervical plate system with titanium cage to treat single level cervical spondylotic myelopathy has advantages of easy manipulation,safe, less complication and higher fusion rate. It is an ideal way for cervical anterior fixation.

BACKGROUND: The assessment of chronic nerve root injury is mainly depend on indirect evidences of imaging results.OBJECTIVE: This study is designed to find out the relationship between the degrees of the pathological changes of nerve roots and motor evoked potential (MEP) changes due to chronic compression.DESIGN: A self-controlled trial with animals as subjects.SETTING: Spine Surgery Department of the Second Clinical Hospital of Jinan University.MATERIALS: The trial was completed in the Spinal Surgery Department of the Second Clinical Hospital of Jinan University from October 2001 to May 2003. The subjects were 30 healthy cats of either gender weighing 3 to 5 kg.INTERVENTIONS: The compression model was established by wedging a Ⅴ-shape bone flap into the right intervertebral foramens between C7, C8 and T1 vertebrae. The left foramens served as controls. The cats underwent CT examination on the 2nd, 4th, 8th and 12th postoperative week to show the foramen changes. Six randomly selected cats underwent magnetic stimulation MEP each time on the 2nd, 4th, 8th, 12th and 24th week. The injuries to the compressed nerve roots were assessed according to Mackinnon Standard and they were compared with the MEP wave.MAIN OUTCOME MEASURES: Whether the superficial magnetic stimulated MEP monitoring result was in correspondence with the pathological changes of the chronically compressed nerve roots.RESULTS: The MEP did not show any abnormal changes for Grade Ⅰ injury prolonged to 9.6- 10. 2 ms. There was almost no evoke potential at all stimulation points for grade Ⅴ nerve root injury.CONCLUSION: That the injured nerve root presents dysesthesia and normal MEP results suggests grade Ⅰ injury. Prolonged latency including prolonged F wave suggests grade Ⅱ injury. And additional amplitude decrease together with widened and unclassifiable waves implies the injury be grade Ⅲ. The prominent features of grade Ⅳ nerve injury is much more decreased amplitudes and more prolonged latency. For grade Ⅴ injury there is always disappearance of whole MEP or some potential components. The superficial magnetic stimulated MEP monitoring results are in correspondence with the pathological changes of the nerve roots due to chronic compression, which means MEP monitoring results could serve as the quantitative indication to pathological changes of nerve injury.

BACKGROUND: Many clinical cases have proved that the satisfactory reposition, fusion and internal fixation in the internal fixation for inferior lumbar spondylolisthesis are not consistent with the postoperative symptoms and physical signs, and functional restoration.OBJECTIVE: To investigate the application of somatosensory evoked potential(SEP) in the monitoring during internal fixation for inferior lumbar spondylolisthesis, and the effects of SEP monitoring on the improvement of postoperative symptoms and the spinal functions as well.DESIGN: A randomized controlled trial.SETTING: Inpatient department of spinal surgery, an affiliated hospital of a university. PARTICIPANTS: Fifty-two patients with inferior lumbar spomlylolisthesis including 23 male and 29 female cases aged between 18 and 68 years old were admitted by the Department of Spinal Surgery, Second Affiliated Hospital(Shenzhen People's Hospital) of Jinan University, from June 2000 to December 2003. All cases were randomly divided into control group(n = 20) and monitor group ( n = 32).METHODS: SEP induced by segmental stimulation in cutaneous nerve was used in the control group for preoperative and intraoperative monitoring, and postoperative follow up. The intraoperative potential changes in patients with excellent and good improvement in postoperative functions had been retrospectively investigated to confirm the effective indices for intraoperative monitoring, which thereby provided references for intraoperative monitoring in patients of monitor group.MAIN OUTCOME MEASURES: ① Evaluation of postoperative spinal function; ② SEP latency and amplitude.RESULTS: SEP values after postoperative anesthesia were set as basis.The manifestations of intraoperative potential alterations: ① If the latency reduced 10% -15% or the amplitude increases more than 40% after fixation, it suggested favorable prognosis; ② The potential indices were stable during monitoring, or the reduction of latency was less than 10%,or the increase of amplitude was less than 30%, the fixation could be continued, and partial functions of nerve root and symptoms could be improved after surgery; ③ During the surgery, if potential indices had transient lluctuation, which could be recovered to basic potential within 15 to 20 minutes, fixation should be stopped during the fluctuation. Still partial functions of nerve root and symptoms could be improved after surgery; ④If the intraoperative latency prolonged more than 5%, or amplitude reduced more than 10%, or part of the components disappeared, or the wave shape dispersed, it might suggest postoperative aggravation of pain and dyskinesia. So intraoperative adjustment was necessary. The coincident rate of the improvement of the indices of intraoperative monitoring and the improvement of postoperative spinal function reached 93.75%.CONCLUSION: SEP induced by segrmental stimulation in cutaneous nerve is an objective and effective method in the monitoring and instruction of decompression, reposition, fixation of internal fixation for inferior lumbar spondylolisthesis, which has important merits in the improvement of the function of nerve root and the restoration of spinal function.

Objective To investigate the causes and prevention on complications of percutaneous vertebroplasty(PVP). Methods Forty three cases with 64 vertebrae were performed PVP from May 2001 to October 2003. The incidence of complication was 13 cases (30.2%). Leakage of polymethylmethacry (PMMA) without symptoms occurred in 4 cases. Leakage with pain occurred in 3 cases. No leakage but with pain occurred in 4 cases after the procedure. Fracture of adjacent vertebrae occurred in 2 cases. All cases were followed up from 3 to 29 months (in average of 13.2 months). Results There wasn′t severe complications in 7 leakage cases. The pain in 7 cases was relieved and disappeared at 2-7 days after the procedure. The symptoms of pain in 2 cases of adjacent vertebrae fracture were relieved. Conclusion If sufficient preventive measures are applied before or during the procedure of PVP,the complications may be reduced effectively.