Progress in Intraoperative Neurophysiological Monitoring for the Surgical Treatment of Thoracic Spinal Stenosis

Thoracic spinal stenosis (TSS) is a group of clinical syndromes caused by thoracic spinal cord compression, which always results in severe clinical complications. The incidence of TSS is relatively low compared with lumbar spinal stenosis, while the incidence of spinal cord injury during thoracic decompression is relatively high. The reported incidence of neurological deficits after thoracic decompression reached 13.9%. Intraoperative neurophysiological monitoring (IONM) can timely provide information regarding the function status of the spinal cord, and help surgeons with appropriate performance during operation. This article illustrates the theoretical basis of applying IONM in thoracic decompression surgery, and elaborates on the relationship between signal changes in IONM and postoperative neurological function recovery of the spinal cord. It also introduces updated information in multimodality IONM, the factors influencing evoked potentials, and remedial measures to improve the prognosis.     

Early neurosurgical intervention of spinal cord contusion: an analysis of 30 cases

Background The incidence of spinal injury with spinal cord contusion is high in developed countries and is now growing in China. Furthermore, spinal cord injury happens mostly in young people who have a long life expectance. A large number of patients thus are wheelchair bound for the rest of their lives. Therefore, spinal cord injury has aroused great concern worldwide. Despite great efforts, recovery from spinal cord injury remains unsatisfactory. Based on the pathology of spinal cord contusion, an idea of early neurosurgical intervention has been formulated in this study. Methods A total of 30 patients with ＂complete＂ spinal cord injury or classified as American Spinal Injury Association （ASIA）-A were studied. Orthopedic treatment of the injured vertebra（e）, internal fixation of the vertebral column, and bilateral laminectomy for epidural decompression were followed directly by neurosurgical management, including separation of the arachnoid adhesion to restore cerebrospinal fluid flow and debridement of the spinal cord necrotic tissue with concomitant intramedullary decompression. Rehabilitation started 17 days after the operation. The final outcome was evaluated after 3 months of rehabilitation. Pearson chi-square analysis was used for statistical analysis. Results All the patients recovered some ability to walk. The least recovered patients were able to walk with a wheeled weight support and help in stabilizing the weight bearing knee joint （12 cases, 40%）. Thirteen patients （43%） were able to walk with a pair of crutches, a stick or without any support. The timing of the operation after injury was important. An optimal operation time window was identified at 4-14 days after injury. Conclusions Early neurosurgical intervention of spinal cord contusion followed by rehabilitation can significantly improve the locomotion of the patients. It is a new idea of a therapeutic approach for spinal cord contusion and has been proven to be very successful.     

The biomechanical effects of pedicle screw adjustments on the thoracolumbar burst fractures

The biomechanical effects of pedicle screw adjustments on the thoracolumbar burst fractures Shang jian, Ling xiaodong, Han xiguang, et al The First Affiliated Hospital Of Harbin Medical University Background: Posterior pedicle screw device is widely to apply treatment of thoracolumbar burst fractures. As the clinical operation is not based upon quantitative data of adjustments, the results are not optimal. At present, no study has assessed the associations between the device adjustments and the restoration of stiffness. Objectives: To investigate the biomechanical effects that adjustments of a pedicle screw device have on the burst fracture, and explore an optimal adjustment. Methods: Burst fractures were produced at L1 vertebra in twenty-four fresh calf spines (T12-L3). The specimens divided into four groups at random. Pedicle screw devices were attached to T13 and L2. Four device adjustments, consisting of distraction and extension, were applied. Adjustment 1 was pure 6° extension. Adjustment 2 was pure 5mm distraction. Adjustment 3 was 6° extension followed by 5mm distraction. Adjustment 4 was 5mm distraction followed by 6° extension. Analysis and evaluate the effect of each adjustment on the stiffness restoration, anatomical reduction and neural decompression for the burst fractures. Results: Pure extension (group 1) produced the closest segment height and the least restoration of the canal to the intact. Pure distraction (group 2) restored stiffness most, but only with 60% stiffness of the intact value, and lost the segmental angle most to the intact. The combination of extension-distraction (group 3 and group 4) produced the maximum reduction of the anatomy and restoration of the canal in the burst fracture, and the least stiffness restoration. The sequence of extension and distraction did not affect stiffness restoration, anatomical reduction and neural decompression. Conclusions: The device adjustments affected stiffness restoration, anatomical reduction and neural decompression. The combined extension-distraction adjustment may be the most suitable considering the anatomical reduction and neural decompression, but its stiffness decreased the most, if necessary; it should be considered to reconstruct L1 vertebral. Key words: Burst fracture, Pedicle screw, Stiffness, Adjustment 1. Introduction Nearly 90% of all spinal fractures occur in the thoracolumbar region, and burst fractures compose approximately 15% of such injuries. Burst fractures occur predominantly in the younger patients, incurring a high financial and society cost [1]. There have been many reports suggesting appropriate therapies for burst fracture. Surgery is still controversial, but is gradually being accepted. The ideal goal of the surgical treatment of burst fracture is neural decompression and anatomical reduction and ambulation as early as possible. Generally, surgical treatment is generally divided into two types: anterior and posterior. The anterior approach provides good decompression and solid fusion, but the operative risks relatively higher than that associated with the posterior approach. On the other hand, the posterior procedure of the thoracolumbar junction is well established, with advantages such as more safety and less being technically demanding. There are many surgical devices for the posterior approach. Nowadays, use of pedicle screw has become increasingly popular. Theoretically, pedicle screw fixation provides greater forces to be applied to the spine to reduce deformity because of its 3-column fixation characteristics. Short-segment fixation is the most common and most simple treatment of burst fractures. The need to fuse fewer segments is treated with short-segment fixation in comparison with longer-segment fixation [2]. Pedicle devices are used not only to provide temporary fixation, but also to restore the vertebral spinal alignment and to reduce the canal encroachment. The stabilizing potential of the pedicle screw device adjustments has been rarely studied. As the operation procedure is not based upon quantitative data, the results obtained are not optimal. A fracture vertebra does not transfer load as effectively as the intact vertebra [3]. Patients who undergo surgery using short-segment pedicle screw instrumentation for middle-column injury may experience implant failure. The compressive stiffness of the spine reflects the load-sharing between the implant and the injured spinal column. To our knowledge there are no experimental studies that have has assessed the associations between the device adjustments and the restoration of stiffness. We hypothesized that the pedicle screw adjustments affected the restoration of segment stiffness. The purpose of the current study was to investigate the effects that adjustments of a pedicle screw device had on the reduction of the burst fracture, including anatomical reduction, neural decompression, and especially stiffness restorations, then to explore an optimal adjustment. 2. Materials and methods 2.1. Specimen Preparation Twenty four thoracolumbar spinal specimens from twenty-one-day-old fresh calves were retrieved from an abattoir and frozen at −20 °C. There was no trauma history associated with any of these specimens. Of the specimens, ten were female and fourteen were male with an average age of 6.8 days (range, 5-9 days). After defrosting for twenty-four hours, the specimens were cut into five-vertebra segments (T11-L3), excess paravertebral muscle was removed. The ends of the specimen were set in 80-mm-diameter polymethylmethacrylate end plates to produce flat, parallel surfaces. The instrument used spinal internal fixation system (Beijing Orthopedic Innovation, Inc, China), the screw length and diameter were 5.0 mm and 35 mm respectively. 2.2 Experimental Burst Fracture Production Experimental burst fractures were produced at the L1 vertebra using an incremental impact protocol [4]. An impact mass, guided by a vertical tube, was dropped onto an impounder resting on top of the specimen. The average drop height was 1.4 m, resulting in an impact speed of 5.2 m/sec. A wedge of 8 ° wedge angle was placed between the impounder and the specimen top to force the latter into a flexed posture, so that the mechanism of loading was flexion-compression. Each specimen was impacted with an initial mass of 3.3 kg. If no burst fracture occurred, the mass was increased by 2.0 kg for the next impact. The burst fracture occurrence was monitored by measuring the canal encroachment on lateral radiograph taken after each impact. This incremental addition was continued until a burst fracture of requisite severity (10-80% encroachment,) occurred. 2.3 Pedicle Screw Device After burst fracture, two pairs of pedicle screws were inserted into the T12 and L2 pedicle using the standard clinical technique. In T13 the screws were inserted approximately 30-32 mm in depth and in L2 to a 35-mm depth. To avoid loosening of the interface between the specimen and the screw during repeated loads, polyester resin was poured. An internal fixator rod system was attached to left and right pairs of the screws. This pedicle screw system allowed us to independently apply two device adjustments (translation or angulation) in the positive or negative direction, or a combination. 2.4 Device Adjustments The specimens divided into four groups at random. Four device adjustments were chosen with combinations of translation and angulation. The choice was governed by 1) clinical relevance, 2) no injury to the specimen due to the result of any adjustment, 4) the decreased segmental height and angle of the burst fracture, and 3) only a finite number of adjustments could be studied. Burst fractures are caused by flexi- and -axial loading forces and thus seem best treated posteriorly with reduction and fixation by extension and distraction. Clinically, the burst fracture is often put in some extension to restore spinal lordosis and some distraction to restore spinal height, but seldom in flexion or distraction. We chose four device adjustments which were studied. (Table 1) The four device adjustments, from left to right, respectively, consist of 6° pure extension (0/6°E), 5 mm pure distraction (5D/0°), 6° extension was followed by 5 mm distraction (5D/6°E) and 5 mm distraction was followed by 6° extension(5D/6°E). Table 1 Four device adjustments Adjustments After Burst Fracture 1 2 3 4 Distraction（mm） 0 5 5 5 Extension（°） -6 0 -6 -6 Group 1, 2 were single adjustments, whereas group 3, 4 were combinations. 2.5 Biomechanical test and CT scan All specimens were subjected to five cycles of 0-250 N flexion-and axial-compression in a displacement-controlled mode at a rate of 25 mm/min on a testing machine (Instron 5569, China). Two load cycles were used to precondition the specimen. At each step on each load cycle, the specimen was allowed to creep for 30 seconds to reduce variations resulting from viscoelasticity of the spine. Load-displacement curves were automatically recorded. The axial-compression and flexion-compression curves were computed in the three conditions: intact, burst fracture, and burst fracture with each of the four device adjustments. The stiffness (N/mm) was defined as the linear slope of the curve (Fig. 1). Fig. 1 Diagrams of biomechanical setup (a: Axial compression. b: Flexion compression) All specimens in the three conditions, intact, burst fracture, and burst fracture with each of the four device adjustments, was taken for CT scanning and 3D reconstruction. (Fig. 2) Then according to the images, the segment height and angle (Fig 3), as well as the diameter of the L1 canal were measured. We defined this as the intact neutral posture, under no load. Therefore, height, angle and diameter were measured with the intact specimen in neutral posture. Fig.2 CT scanning (A2-C2) and 3D reconstruction (A1-C1) of a specimen in three conditions, intact, fracture, and fracture with the device adjustment Fig. 3 Definition of the segment height and angle (Line a is tangent to the lower endplate of T13. Line b is parallel to line and passes through the posterior-inferior corner of the L2 vertebral body. Line c is tangent to the lower endplate of T13) 2.6 testing protocol Three spinal conditions, intact, burst fracture, and burst fracture with each of the four device adjustments, were studied. A flow chart depicting testing sequence is provided in Fig. 4 Fig. 4 Experimental protocol showing the sequence of events for each specimen (CT & 3D: CT scanning and 3D reconstruction. AFCT: axial and flexion compression testing) 2.7 Statistical analysis Statistical analysis was performed using SPSS 10.0 software (SPSS/PC Ins, Chicago, IL, USA). Mean and standard deviations were computed of the segmental heights and angles, the diameter of the canal and the stiffness under axial- and flexion-compression. The differences among the four device adjustments were analyzed by one-factor analysis of variance. The differences within the same group were evaluated with t-tests. Significance was set at P<0.05. 3. Results Specimens experienced 3.4 times impact on average and the impact energy and speed on average by 94.2 J and 5.24 m/s respectively, then the L1 vertebral body produced burst fractures. The average intact axial-compression and flexion-compression stiffness were 380.7±58.5 N/mm and 339.2±42.1 N/mm respectively. After burst fractures, axial-compression and flexion-compression stiffness were 109.8±33.8 N/mm and 72.9±20.0 N/mm respectively. Both axial- and flexion-compression stiffness decreased significantly after injury as compared with intact spine (axial t=18.8, p<0.01; flexion t=16.6, p<0.01). We found the device adjustment to affect the burst fracture axial- and flexion-compression stiffness, but no adjustment provided stability close to the intact specimen (axial p<0.05; flexion p<0.05). Among the four device adjustments, 5 mm pure distraction (5D/0°) stabilized the most (axial p<0.05; flexion p<0.05), with a 28% and 35% relative decreasing of axial- and flexion-compression stiffness. The combined distraction-extension adjustments (5D/6°) stabilized the least (axial p<0.05; flexion p<0.05), and the sequence of applying distraction and extension did not affect the spinal stability (axial p>0.05; flexion p>0.05). Stiffness under flexion-compression was significantly lower than that under axial-compression in every state (p < 0.05). Table 2 Axial- and flexion-compression stiffness for intact, burst fracture and four device adjustments ( ±S, n=6). Intact Burst Fracture Adjustment After Burst Fracture 1 2 3 4 Axial-compression Stiffness(N/mm) 380.7±58.5 109.8±33.8 213.1±43.6 275.1±37.7 183.8±27.6 179.3±22.1 Flexion-compression Stiffness( (N/mm) 339.2±42.1 72.9±20.0 176.8±34.7 220.3±26.5 140.8±21.0 136.5±19.2 Fig. 5 Axial and flexion compression stiffness of each construct. The burst fracture decreased the segmental height on average by5.3±2.5 mm, and the segmental angle changed to kyphosis by 5.9±4.5°. The adjustments, with respect to the burst fracture, caused varying changes in the spinal posture. The combined distraction-extension adjustments (5D/6°) brought the burst fracture closer to the intact state than other adjustments (p>0.05). The postural changes due to group 3 versus 4 were not significantly different (p>0.05). Thus, the sequence of applying distraction and extension did not affect the spinal postural change. Pure adjustment caused spinal changes in spinal posture. For example, 5 mm pure distraction was accompanied by some kyphosis (height t=3.51, p<0.05; angle t=2.90, p<0.05), and 6° pure extension also produced some distraction (height t=2.97, p<0.05; angle t=3.54, p<0.05). Compared with the intact spine, pure distraction produced the segmental angle that deviated from the intact mostly (p<0.05); while pure extension produced the segmental height deviated from the intact mostly (p<0.05). Table 3 Changes in segmental height and segmental angle, from the burst fracture to the resulting postures due to the device adjustments ( ±S, n=6). Device adjustment 1 2 3 4 Segment height(mm) 1.9±0.8 2.9±1.8 6.0±1.3 5.8±1.4 Segment angle(°) -4.5±1.7 0.5±1.1 -3.8±1.9 -4.0±2.0 Fig. 6 Average changes in the posture from the burst fracture due to the four adjustments. On average, adjustment 2, 3, and 4 restored the canal diameter to approximately 70% of its intact value, but none restored to its intact values (Group 1: t=7.32, p<0.05; Group 2: t=4.92, p<0.05; Group3 t=3.39, p<0.05; Group 4: t=3.29, p<0.05). The combined distraction-extension adjustments (5D/6°) were found to produce the maximum restorations of canal diameter (p<0.05). The restorations due to group 3 versus 4 were not significantly different (p>0.05). Thus, the sequence of applying distraction and extension did not affect to decompress the canal (p<0.05). Table 4 Canal diameters for intact, burst fracture, and four device adjustment ( ±S, n=6). Intact Burst Fracture Adjustment After Burst Fracture 1 2 3 4 Canal diameter(mm) 14.2±1.1 8.3±2.0 9.7±2.1 10.1±2.7 11.1±2.2 11.3±1.9 Fig. 7 Restorations. The parameters indicate the magnitudes of restoration achieved as percentage of the intact values. Restoration (%) = 100 × DAdj/DIntact. DIntact: Intact canal diameter. DAdj: the canal diameter resulting from an adjustment. 4. Discussion Pedicle screw devices are versatile and used not only to provide fixation for an unstable spine, but also to reduce the canal encroachments and to restore the vertebral spinal alignment. These reductions and restorations are accomplished by adjusting the pedicle device, that is, by applying a combination of distraction and/or extension. In previous 3-dimensional testing studies the device adjustments affected the spinal construct stability differently in different directions [5]. But our results differ from the findings of previous studies because of the different load protocol used. We did not use the range of motion parameters in three planes of motion (flexion/extension, left/right lateral bending, and left/right axial rotation) because the compressive stiffness of the tested structure reflects the load-sharing between the implant and the injured spinal columns. Therefore, only the axial-compression and flexion-compression stiffness were calculated in the present study. The present biomechanical analysis showed that pedicle screw device fixation alone did not provide sufficient stability, especially under flexion-compression load. This may explain the fact that short-segment posterior instrumentation alone cannot completely prevent reduction loss and implant failure in treating burst fractures [3, 6]. The results of our study showed that compared with the intact spine, a 39% and 50% relative decrease of axial- and flexion-compression stiffness was noted after the burst fracture. Wang et al [7]. have also showed that despite fixation of the injured spine with pedicle screw instrumentation, the axial-compression and flexion-compression stiffness was still significantly lower than that of the intact spine. This may explain the fact that short-segment posterior instrumentation alone cannot completely prevent reduction loss and implant failure in treating burst fractures. Haher et al. [8] have shown that the anterior and middle column destruction of the spine reduces its load-carrying capacity (LCC) for flexion loads by 70%, while minimal change was observed in the LCC when the axis of loading was posterior to the posterior longitudinal ligament. Our study also demonstrated that the stiffness under flexion-compression was significantly lower than that under axial-compression, indicating mechanical properties in flexion were weaker. Thus patients should possibly be encouraged to rest in bed during the first three postoperative months. In this period, they should wear a brace when ambulating, and avoid activities that require bending forward. Although braces may not reduce loads on internal spinal fixation devices, they may protect the instrumented spine from the reflex overaction of the back muscles caused by sudden events, which substantially increases spine compressive loading [9-10]. In this way, the load on the anterior column may be reduced, and the incidence of early failure of implants may diminish. The adjustment combining 5mm distraction with 6° extension brought the spinal anatomy and the canal diameter closest to the intact state, while that provided axial- and flexion-compression stiffness smallest, compared to all other adjustments. Pure distraction achieved the maximum stability in axial- and flexion-compression stiffness. With this adjustment, posterior fixation could only restore the axial- and flexion-compression stiffness by 72% and 65% respectively. Transpedicular fixation alone cannot provide sufficient stability for thoracolumbar fractures. Posterior instrumentation combined with an anterior graft could offer as a possible solution. Wang et al. have showed that anterior graft with short-segment instrumentation for burst fracture greatly increases the biomechanical stability in the injured spine, thus suggesting that additional reconstruction of the anterior column may be necessary. The adjustments caused varying changes in anatomical reduction, neural decompression, especially stiffness restorations. The results of the study showed that the device adjustments of distraction and extension can be applied in any sequence, with the same results. For the decompression of the neural canal, the sequence of distraction and extension has been deemed important. Harrington et al. [11] suggested applying the distraction first, followed by extension. This was suggested based upon the concept that positioning the vertebra in lordosis without applying distraction significantly slackens the posterior longitudinal ligament. However, this concept was not based upon any quantitative data. Two limitations of the current study should be noted. The one is that the calf spine differs from the human spine anatomically, and mechanically. Despite these differences, the calf spine has been used widely to mode fractures because of its low variability and good bone quality. Another practicality of the calf model lies in structurally more closely replicated human anatomy in surgical techniques [12]. The other is that it was an in vitro study. The properties of the muscles and the muscle tone are absent. Also, the weight bearing and the dynamic muscle forces that will be present once the patient is up and performing daily activities also are absent. In clinical, the severity of the burst fracture can vary greatly. We have presented average results. The individual specimen results will vary from these average values. It is suggested that in future clinical studies the exact adjustments used in the pedicle screw devices be noted at the time of surgery. This will provide important information for subsequent further studies. References 1. Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine 1983; 8: 817-31. 2. Dai LY, Jiang SD, Wang XY, et al. A review of the management of thoracolumbar burst fractures. Surg Neurol 2007; 3: 221-31. 3. MeCormack T, Karaikovie E, Gaines RW. The load sharing classification of spine fractures. Spine 1994; 19: 1741-4. 4. Panjabi MM, Hoffman H, Kato Y, et al. Superiority of incremental trauma approach in experimental burst fracture studies. Clin Biomech 2000; 15: 73-8. 5. Oda T, Panjabi MM. Pedicle screw adjustments affect stability of thoracolumbar burst fracture. Spine 2001; 26: 2328-33. 6. Cunningham BW, Sefter JC, Shono Y, et al. Static and cyclical biomechanical analysis of pedicle screw spinal constructs. Spine 1993; 18: 1677-88. 7. Wang XY, Dai LY, Xu HZ, et al. Biomechanical effect of the extent of vertebral body fracture on the thoracolumbar spine with pedicle screw fixation: an in vitro study. J Clin Neurosci 2008; 15: 286-90. 8. Haher TR, Tozzi JM, Lospinuso MF, et al. The contribution of the three columns of the spine to spinal stability: a biomechanical model. Paraplegia 1989; 27: 432-9. 9. Mannion AF, Adams MA, Dolan P. Sudden and unexpected loading generates high forces on the lumbar spine. Spine 2000; 25: 842-52. 10. Chen HH, Wang WK, Li KC, et al. Biomechanical effects of the body augmenter for reconstruction of the vertebral body. Spine 2004; 29: 377-8 11. Harrington RM, Budorick T, Hoyt J, et al. Biomechanics of indirect reduction of bone retropulsed into the spinal canal in vertebral fracture. Spine 1993; 18: 692-9. 12. Wilke HJ, Krischak S, Claes L. Biomechanical comparison of calf and human spines. Orthop Res 1996; 14: 500-3.     

A SURVEY OF THE TREATMENT OF TRAUMATIC PARAPLEGIA BY TRADITIONAL CHINESE MEDICINE

Traumatic paraplegia is caused by inju-ry to the spinal cord or nerves in caudaequina due to fracture of the spinal columnor intervertebral dislocation.The result issensory disturbance in the lower limbs andthe accompanying loss of motor functionalong with urinary and defecationdysfunction.During the past thirty years in-vestigation on treating many aspects ofparaplegia with traditional Chinese medi-     

An experimental study of spinal cord evoked potential.

The characteristics of spinal cord-evoked potentials were investigated by using an in vitro spinal cord preparation. The spinal cord isolated from adult rats was immersed in a bathing chamber filled with oxygenated artificial cerebrospinal fluid (aCSF). The spinal cord-evoked potentials elicited by the stimulation of the spinal cord were recorded by using bipolar platinum electrodes. The potentials recorded consisted of early and late negative components (N1, N2). The inhibitory effect of lowered temperature on the N1 potential was clearly demonstrated. The oxygen deprivation of aCSF showed the higher sensitivity of N2 potential to hypoxia than that of N1. It was also possible to analyze the effects of potassium and magnesium ion concentration and pH on the evoked potentials. These results showed that the pure effects of various physiological and chemical factors on the spinal cord-evoked potentials can be analyzed by this experimental model.     

Efficacy of Spinal Pia Mater Incision and Laminoplasty Combined with Internal Fixation for Old Spinal Cord Injury

Objective To evaluate the clinical efficacy of incising spinal pia mater to relieve pressure and unilateral open-door laminoplasty with internal screw fixation for treatment of the dated spinal cord injury. Methods From March, 2009 to July, 2010, 16 cases with chronic cervical cord injury underwent spinal dura mater incision and unilateral open-door laminoplasty with internal screw fixation. Nerve functions of preand postoperation were evaluated by Frankel classification and the Japanese Orthopaedic Association (JOA) scale. The improvement rate of JOA score at the indicated time was recorded. Results Postoperative Frankel classification rating of 16 patients improved obviously. JOA scores at the 1st month, 3rd month, 6th month, and 12th month after surgery were 7.9±2.3, 8.5±1.6, 8.9±2.1, and 12.4±2.5, respectively, and significantly increased compared with that prior to surgery (5.5±0.6). At the end of follow-up period, JOA score was significantly higher than that of pre-treatment (P<0.05). The recovery was relatively rapid during the first 3 months following the surgery, then entered a platform period. Conclusion It is effective for patients with dated spinal cord injury to undergo spinal decompression and laminoplasty.     

Induction of functional recovery by co-transplantation of neural stem cells and Schwann cells in a rat spinal cord contusion injury model

Objective To study the transplantation efficacy of neural stem cells （NSCs） and Schwann cells （SC） in a rat model of spinal cord contusion injury. Methods Multipotent neural stem cells （NSCs） and Schwann cells were harvested from the spinal cords of embryonic rats at 16 days post coitus and sciatic nerves of newborn rats, respectively. The differential characteristics of NSCs in vitro induced by either serum-based culture or co-culture with SC were analyzed by immunofluorescence. NSCs and SCs were co-transplanted into adult rats having undergone spinal cord contusion at T9 level. The animals were weekly monitored using the Basso-Beattie-Bresnahan locomotor rating system to evaluate functional recovery from contusion-induced spinal cord injury. Migration and differentiation of transplanted NSCs were studied in tissue sections using immunohistochemical staining. Results Embryonic spinal cord-derived NSCs differentiated into a large number of oligodendrocytes in serum-based culture upon the withdrawal of mitogens. In cocultures with SCs, NSCs differentiated into neuron more readily. Rats with spinal cord contusion injury which had undergone transplantation of NSCs and SCs into the intraspinal cavity demonstrated a moderate improvement in motor functions. Conclusions SC may contribute to neuronal differentiation of NSCs in vitro and in vivo. Transplantation of NSCs and SCs into the affected area may be a feasible approach to promoting motor recovery in patients after spinal cord injury.     

THORACIC SPINE FRACTURES

Objective. To investigate the unique characteristics and treatment of thoracic spine fractures. Methods. Seventy-seven patients with thoracic spine fractures were retrospectively reviewed. Of these, there were 37 compression fractures, 34 fracture-dislocations, 3 burst fractures and 3 burst-dislocations. Twenty-six patients had a complete lesion of the spinal cord, 14 sustained a neurologically incomplete injury, and 37 were neurologically intact. Fifty-three patients were treated nonoperatively and 24 treated operatively. Resu/ts. All patients were followed up for 2 -15 years. None of the 26 patients with a complete lesion recovered any significant function. Of 37 neurologically intact patients, 13 had local pain although all of them remained normal function. Two of 14 patients with incomplete paraplegia returned to normal, 7 recovered some function and 5 did not recovered. Conclusions. Because of the unique anatomy and biomechanlcs of the thoracic spine, the classification commonly applied to thoracolumbar fractures is not suitable for thoracic fractures. Fusion and instrumentation are indicated when the fractures are unstable, while patients with incomplete lesion of the spinal cord may be the candidates for supplemented decompression.     

Surgical treatment of metastatic spinal tumors

Objective The patients with metastatic spinal tumors often suffered from severe back pain and spinal cord compression directly caused by tumor tissue or severe spine kyphosis. In order to treat or prevent spinal cord paralysis, decompression and stabilization should be performed on the patients with spinal pain and/or severe spinal cord compression. Methods From July 1998 through July 2001,62 patients (27 women and 35 men) with metastatic spinal tumors had been treated at our department. Of 62 patients, the thoracic vertedbrae were involved in 37 cases, lumbar vertebrae in and cervical vertebrae in 6. Among 43 of 62 patients who presented with neurological dysfunction, 24 patients were incompletely paraplegic and the others were completely paraplegic. The follow-up ranged form 8 to 36 months. Results Pain relief was obtained in 58 of 62 patients (94%), and good neurological recovery was obtained in 33 of the 43 patients. Improved bowel and bladder function was obtained in 12 of 25 patients who presented     

Intraoperative ultrasonography in “cave-in” 360° circumferential decompression for thoracic spinal stenosis

Background  The surgical outcomes of decompression for thoracic spinal stenosis (TSS) are unfavorable. The purpose of this study was to determine the efficacy of intraoperative ultrasonography during “cave-in” 360° circumferential decompression surgery in patients with TSS.

Methods  Thirteen patients with TSS underwent “cave-in” 360° circumferential decompression surgery between May 2010 and November 2010. Intraoperative ultrasonography was used after removal of the posterior wall of thoracic spinal canal to assess the morphologic restoration of the spinal cord and the anterior surface of the spinal canal. In seven patients, ultrasonography was used again after circumferential decompression to compare the cross-sectional area of the spinal cord before and after circumferential decompression.

Results  The average period of follow-up was (12±2) months (range 9–15 months). The Japanese Orthopedic Association score was significantly higher at the final follow-up (8.5±2.1, range 3–10) than preoperatively (5.2±1.1, range 3–7; P <0.01). The cross-sectional area of the spinal cord was (30.8±6.6) mm² before and (53.6±19.1) mm² after circumferential decompression (P <0.01). For five patients with TSS caused by thoracic disc herniation, the levels of circumferential decompression performed corresponded to those expected preoperatively. In contrast, for eight patients with TSS caused by ossification of the posterior longitudinal ligament, on average 1.6±0.9 fewer levels of circumferential decompression were performed than expected preoperatively.

Conclusions  “Cave-in” 360° circumferential decompression is an effective therapeutic option for TSS. Intraoperative ultrasonographic evaluation may reduce the levels of circumferential decompression and ensure sufficient decompression, and increase the efficacy of this surgical technique.

     

前路减压、植骨及内固定治疗胸腰椎爆裂骨折

目的探讨胸腰椎爆裂骨折前路减压固定的可能性。方法2001年5月￣2005年1月,收治32例胸腰段骨折合并脊髓损伤患者。其中T1212例,L117例,L23例。按Franke1分级评定:A级6例,B级5例,C级7例,D级14例。手术均行前路减压内固定术。结果32例术后影像学检查胸腰椎生理弧度基本恢复正常。均获随访10～51个月,平均17.9个月。神经功能除2例脊髓完全损伤无恢复外,其余均有不同程度改善。未出现钢板螺钉松动断裂、继发性脊柱后突及节段性不稳等并发症。结论前路减压内固定修复重建严重胸腰椎爆裂骨折,具有减压彻底、植骨充分及内固定牢固等特点,有助于椎体高度恢复和神经功能改善。     

不同手术方式治疗胸腰椎爆裂骨折合并脊髓损伤的临床疗效观察

目的 探讨急诊单侧椎弓根减压后路复位固定术治疗合并脊髓损伤的胸腰椎爆裂骨折的临床疗效.方法 对44例合并脊髓损伤的胸腰椎爆裂骨折患者进行手术治疗,观察组21例急诊应用单侧椎弓根减压后路复位固定术治疗,对照组23例择期应用伤椎椎弓根置钉后路复位固定术治疗,比较两组患者术后1周、12个月伤椎前缘高度、脊柱矢状位Cobb角度和椎管前后径,12个月评价神经功能恢复情况.结果 两组患者均成功完成手术,手术时间和术中出血量组间差异无统计学意义（P＞0.05）;术后1周、12个月时伤椎椎管前缘高度、脊柱矢状位Cobb角度组间比较差异均无统计学意义（P＞0.05）;观察组伤椎椎管前后径较治疗前增加,差异有统计学意义（P＜0.05）;对照组与治疗前比较差异无统计学意义（P＞0.05）,观察组改善情况优于对照组（P＜0.05）;术后12个月时观察组神经功能恢复有效率优于对照组（P＜0.05）.结论 急诊应用单侧椎弓根减压后路复位固定术治疗合并脊髓损伤的胸腰椎爆裂骨折,可在短时间内解除脊髓和神经压迫,恢复脊柱的稳定性,有利于神经功能的恢复,具有确切的近期和远期疗效.     

胸腰段爆裂骨折脊柱前路减压手术的临床效果评价

目的观察脊柱前路减压、植骨内固定术治疗胸、腰椎爆裂骨折伴脊髓损伤的治疗效果。方法自1999年10月￣2005年3月间,应用该方法治疗28例胸腰椎爆裂骨折伴全瘫及不全瘫病例。男22例,女6例,年龄21岁￣55岁。CT检查本组病例均存在外伤性椎管狭窄。24例病人采用前路脊髓减压植骨Profile及Z-plate钢板内固定术;4例应用前路脊髓减压植骨Mossmaimi钉棒系统。选用国际脊髓损伤神经功能评定法来评价病人术前、术后的神经功能恢复情况及术前、术后CT检查对比了解脊髓减压、植骨块位置及植骨融合情况。结果28例中22例病人术后脊髓神经功能感觉、运动评分明显恢复(P<0.05),椎体高度恢复且稳定。2例出现脑脊液漏,8天￣14天伤口自行愈合。结论胸腰椎爆裂骨折伴脊髓损伤及椎管狭窄病例采用脊髓前路减压、植骨固定方法,可直接去除脊髓前方的骨性压迫,符合损伤病理。植骨固定不仅恢复椎体高度,而且可获得脊柱的即刻稳定,为脊髓功能恢复创造良好的条件。因此,本组病例脊髓神经功能有明显恢复。     

纳米羟基磷灰石/聚酰胺66复合生物活性人工椎体在骨质疏松性胸腰椎爆裂骨折前路手术中的临床体会

目的:探讨纳米羟基磷灰石/聚酰胺66复合生物活性人工椎体在骨质疏松性胸腰椎爆裂骨折前路手术中应用的手术要点与经验。方法:回顾我院21例骨质疏松性胸腰椎爆裂骨折经前路减压、植骨融合内固定手术病例,从椎管减压、脊柱稳定性重建方法及效果方面,总结手术经验。结果:21例均获得随访,随访时间7个月以上,显示手术后胸腰椎生理曲度恢复满意,CT/MRI复查,椎管容积扩大,致压骨块消失,植入人工纳米羟基磷灰石/聚酰胺66复合生物活性人工椎体已与相邻椎体融合,神经功能恢复(Frankel分级)提高1²级。术中无较大副损伤出现,术后未发生钛合金板与螺丝钉松动、断裂等并发症。结论:骨质疏松性胸腰椎爆裂骨折前路减压彻底,重建方式符合脊柱生物力学分布原则,脊髓功能恢复较好,通过改进内固定技术及支撑材料后,无内固定松动、断裂等并发症,远期脊髓神经再压迫风险小。     

侧前方入路减压、椎体间支撑植骨治疗胸腰椎爆散性骨折

目的探讨胸腰段椎体爆散性骨折的手术治疗方法及疗效分析。方法1996年3月-2002年3月,对16例胸腰段椎体爆散性骨折病人进行了手术治疗,采用侧前方入路行伤椎部分切除减压,支撑植骨,其中12例配合内固定。结果随访9个月至6年半,平均28个月,椎体后凸畸形恢复满意,植骨均获骨性融合,植骨界面消失,神经功能恢复按Frankel分级平均改善1．4级。结论胸腰椎爆散性骨折行侧前方入路具有减压直接、彻底,支撑式植骨强度大,便于安装内固定,有效恢复椎体序列,融合率高,神经功能恢复满意等优点。     

胸腰椎爆裂性骨折的后路治疗疗效观察

目的探讨经椎弓根螺钉系统内固定手术治疗胸腰椎爆裂性骨折的疗效。方法对39例胸腰椎爆裂性骨折患者行透视下后路椎弓根螺钉系统内固定手术治疗或同时行椎管探查减压,植骨融合术。结果术后随访6-48个月,椎体平均高度由术前的前缘48%和后缘73%恢复到术后的前缘93%和后缘97%,Cobb′s角由术前平均25°恢复为术后平均55°。对脊髓损伤的患者按Frankel分级,术后平均提高1.2级。未发现椎弓根钉断裂,骨不愈合。结论椎弓根螺钉系统技术简单,操作方便,创伤较前路小,椎管减压效果仍理想,脊柱融合率较高,神经功能恢复满意,是一种较好的治疗胸腰爆裂骨折的方法。     

胸腰段脊柱脊髓损伤减压与固定相关问题探讨（附166例报告）

目的 对胸腰段脊柱脊髓，马尾神经损伤患者的外科治疗及几种内固定方法的疗效进行探讨。方法 对166例患者的治疗进行回顾分析。该组患者中椎体爆裂性骨折37例，椎体压缩骨折超二分之一109例，椎体骨折脱位14例，多节段或跳跃骨折6例，脊髓损伤按Frankel分级，A级59例，B级46例，C级42例，D级19例，治疗采用后路减压复位122例，前路减压复位，髂骨植骨融合44例。结果 术后123例获3-18个月随访，随访患者中随4例RF钉断裂，5例Harrington上钩脱落，6例棍断裂，其余患者内固定稳固，脊髓，马尾神经恢复，除35例仍为A级外，余脊髓神经功能恢复1-3个级别。结论 各种不同内固定可保持或增强脊柱的稳定，胸腰段脊柱脊髓损伤的外科治疗应根据骨折类型，脊髓及马尾神经损伤程度选择手术入路及内固定材料。     

胸腰椎爆裂骨折28例前路手术并发症分析

目的正确选择胸腰椎爆裂骨折手术治疗方法,减少并发症,以获得最佳脊髓神经恢复和脊柱稳定性.方法胸腰椎爆裂骨折前路手术28例,术前X、CT摄片,部分行MRI平扫;术后分别1月、2月、6月、1 a摄片及部分CT检查,观察固定和减压效果.结果 1例出现乳糜液漏,1例切口疝,1例气胸.经过积极治疗,全部治愈.结论胸腰段前路手术并发症的发生大多数和术者对该段解剖熟知程度、手术技巧和经验有关,而在发生时及时有效的进行对症治疗可将其危害降到最低.     

椎管侧前方减压治疗胸腰椎爆裂骨折伴截瘫

目的总结椎管侧前方减压治疗胸腰椎爆裂骨折伴截瘫的经验.方法采用椎管侧前方减压加植骨治疗胸腰椎爆裂骨折伴截瘫27例.结果经5～60个月随访,按Frankel标准评定,22例等级提高,5例无改善.结论胸腰椎爆裂骨折伴截瘫侧前方椎管减压直接、彻底.     

后路减压植骨AF钉固定治疗胸腰椎爆裂骨折36例观察

目的：探讨使用AF钉内固定并后路减压植骨治疗胸腰椎爆裂骨折的临床效果。方法：测量脊柱术前、术后侧位X线片，cobb’s角、椎管狭窄指数及症状恢复程度，观察后路减压植骨AF钉的疗效。结果：术后随访1-3年，36例除一例完全瘫痪未能恢复外，其余均有不同程度的恢复，总有效率97．22％结论：后路减鹾植骨AF钉固定治疗胸腰椎爆裂骨折疗效显著，值得推广应用。