Percutaneous mesh-container-plasty for osteoporotic thoracolumbar burst fractures: A prospective, nonrandomized comparative study.

OBJECTIVE: This study aimed to compare the clinical and radiological results of percutaneous mesh-container-plasty (PMCP) versus percutaneous kyphoplasty (PKP) in the treatment of osteoporotic thoracolumbar burst fractures. METHODS: A prospective study of 122 patients with osteoporotic thoracolumbar burst fractures was conducted. The patients were nonrandomly assigned to receive PKP (62; 16 men, 46 women) and PMCP (60; 14 men, 46 women). The epidemiological data, surgical outcomes, and clinical and radiological features were compared between the 2 groups. Cement leakage, height restoration, deformity correction, canal compromise, and cement distribution were calculated from the radiographs. Visual pain analog scale (VAS), the Oswestry disability index (ODI), and short-form 36 health survey domains role physical (SF-36 rp) and bodily pain (SF-36 bp) were calculated before surgery and immediately and 2 years after surgery. RESULTS: Although VAS, ODI, SF-36 bp, and SF-36 rp scores improved from 7 (6-9), 71.28±16.38, 22 (0-32), and 25 (0-50) preoperatively to 2 (1-3), 20.02±8.97, 84 (84-84), and 75 (75-100) immediately postoperatively in the PMCP group (p<0.05) and from 7 (6-8), 71.40±13.52, 22 (10.5-31.75), and 25 (0-50) preoperatively to 2 (1-3), 21.78±11.21, 84 (84-84), and 75 (75-100) immediately postoperatively in the PKP group (p<0.05), there was no difference between the 2 groups. The mean cost in the PKP group was less than that in the PMCP group ($5109±231 vs. $6699±201, p<0.05). Anterior, middle, and posterior vertebral body height ratios in the PMCP group were greater than those in the PKP group postoperatively (88.44%±3.76% vs. 81.10%±11.78%, 86.15%±3.50% vs. 82.30%±11.02%, and 93.91%±3.01% vs. 91.43%±6.71%, respectively, p<0.05). The Cobb angle in the PMCP group was lower than that in the PKP group postoperatively (6.67°±4.39° vs. 8.99°±4.06°, p<0.05). Cement distribution in the PMCP group was higher than that in the PKP group (30.48%±5.62% vs. 27.18%±4.87%, p<0.05). Cement leakage was observed to be lesser in the PMCP group (2/60) than in the PKP group (10 vs. 62, p<0.05). CONCLUSION: Both PKP and PMCP treatments seem to have significant ability in pain relief and functional recovery. Despite its higher cost, PMCP treatment may have a better inhibition ability of cement leakage, cement distribution, height restoration, and improvement in segmental kyphosis than PKP treatment for osteoporotic thoracolumbar burst fractures. LEVEL OF EVIDENCE: Level II, Therapeutic Study.

Clinical characteristics and treatment of fracture-dislocation of thoracic spine with or without minimal spinal cord injury.

BACKGROUND: It is important to evaluate clinical efficacy and safety of posterior internal fixation using pedicle screw system. OBJECTIVES: To investigate clinical characteristics of patients diagnosed with fracture-dislocation of the thoracic spine with or without minimal spinal cord. METHODS: Twenty-eight patients with fracture-dislocation of thoracic spine with or without minimal spinal cord injury were retrospectively analyzed. All patients received posterior reduction and internal fixation using pedicle screw system. RESULTS: The mean follow-up duration was 11.4 months. Among 28 patients, 24 cases were complicated with bilateral pedicle or laminal fracture. Preoperatively, the percentage of vertebral displacement was (32.1 ± 20.6)%, significantly declined to (7.5 ± 6.0)% (t= 4.575, P= 0.001) and maintained at (7.9 ± 6.3)% at the final follow-up. Preoperative local kyphosis angle was measured as (16.2 ± 11.3)∘, restored to (15.4 ± 5.9)∘ postoperatively and (15.8 ± 5.4)∘ during the final follow-up. No statistical significance was observed at three time points (all P> 0.05). The remaining 25 patients were evaluated with normal and complete neurological function. No severe complications were observed intra- and postoperatively. CONCLUSIONS: Posterior internal fixation using pedicle screw is an efficacious and safe therapy which achieves proper reduction and preserves spinal cord function.

Autologous nasal chondrocytes delivered by injectable hydrogel for in vivo articular cartilage regeneration.

Cell based tissue engineering serves as a promising strategy for articular cartilage repair, which remains a challenge both for researchers and clinicians. The aim of this research was to assess the potential of autologous nasal chondrocytes (NCs) combined with alginate hydrogel as injectable constructs for rabbit articular cartilage repair. Autologous nasal chondrocytes were isolated from rabbit nasal septum, expanded either on monolayer or in 3D alginate hydrogel. In vitro, DNA quantification revealed that NCs can proliferate stable in 3D alginate matrix, but slower than that cultured in monolayer. Further, a higher synthesis rate of glycosaminoglycans (GAGs) was detected by GAG measurement in 3D alginate culture. Gene expression analysis at different time point (day 1, 7, 14) showed that 3D culture of NCs in alginate up-regulated chondrogenic markers (Col2A1, ACAN SOX9), meanwhile down-regulated dedifferentiation related gene (Col1A1). In vivo, autologous nasal chondrocytes combined with alginate hydrogel were used for repairing rabbit knee osteochondral defect (Alg + NC group). Histological staining indicated that Alg + NC group obtained superior and more hyaline-like repaired tissue both at 3 and 6 months after surgery. Mechanical analysis showed that the repaired tissue in the Alg + NC group possessed similar mechanical properties to the native cartilage. In conclusion, nasal chondrocytes appeared to be a very promising seed cell source for cartilage tissue engineering, and alginate hydrogel can serve as suitable delivery system.

Clinical Efficacy of Percutaneous Kyphoplasty at the Hyperextension Position for the Treatment of Osteoporotic Kümmell Disease.

SUMMARY OF BACKGROUND DATA: Percutaneous kyphoplasty might be effective for osteoporotic Kümmell disease. OBJECTIVE: To investigate the clinical efficacy of percutaneous kyphoplasty in hyperextension for osteoporotic Kümmell disease. STUDY DESIGN: Retrospective study. METHODS: A retrospective analysis was carried out on data from downstream balloon kyphoplasty treatments in hyperextension for 18 patients with osteoporotic Kümmell disease. All cases were single-segment disease affecting T5 (1 case), T7 (1 case), T8 (2 cases), T11 (6 cases), T12 (4 cases), L1 (2 cases), L2 (1 case), or L4 (1 case). Dual-energy x-ray absorptiometry bone mineral density values ranged from -2.8 to -5.8 SD. The sagittal Cobb angle of the involved segment was measured before and after the operation and the final follow-up also included a visual analog pain score (VAS) and the Oswestry Disability Index (ODI) after comprehensive efficacy assessment. RESULTS: All patients were followed up for 12-36 months, with an average of 15.8 months. Patients showed lower back pain relief and improvement in daily life activities. The kyphosis Cobb angle improved from 32.60±3.82 degrees before surgery to 7.60±1.68 degrees after surgery, and VAS and ODI scores significantly improved from 8.7±0.96 points and 88.6±3.76% to 2.6±0.32 points and 28.6±2.67%, respectively. The last follow-up for the kyphosis Cobb angle yielded a value of 9.60±2.06 degrees, and VAS and ODI averaged 2.2±0.26 points and 26.4±2.46%, respectively. Compared with 2 days postoperatively, the differences were not statistically significant. Intervertebral cement leakage occurred in 1 case, but no symptom was observed and no treatment was performed. CONCLUSION: Percutaneous balloon kyphoplasty in the hyperextension position is an effective method for osteoporosis in Kümmell disease.

Biomechanical study of the funnel technique applied in thoracic pedicle screw replacement.

BACKGROUND: Funnel technique is a method used for the insertion of screw into thoracic pedicle. AIM: To evaluate the biomechanical characteristics of thoracic pedicle screw placement using the Funnel technique, trying to provide biomechanical basis for clinical application of this technology. METHODS: 14 functional spinal units (T6 to T10) were selected from thoracic spine specimens of 14 fresh adult cadavers, and randomly divided into two groups, including Funnel technique group (n = 7) and Magerl technique group (n = 7). The displacement-stiffness and pull-out strength in all kinds of position were tested and compared. RESULTS: Two fixed groups were significantly higher than that of the intact state (P < 0.05) in the spinal central axial direction, compression, anterior flexion, posterior bending, lateral bending, axial torsion, but there were no significant differences between two fixed groups (P > 0.05). The mean pull-out strength in Funnel technique group (789.09 ± 27.33) was lower than that in Magerl technique group (P < 0.05). CONCLUSIONS: The Funnel technique for the insertion point of posterior bone is a safe and accurate technique for pedicle screw placement. It exhibited no effects on the stiffness of spinal column, but decreased the pull-out strength of pedicle screw. Therefore, the funnel technique in the thoracic spine affords an alternative for the standard screw placement.

[Suture anchor for acute injuries of medial collateral ligament of knee at degree III].

OBJECTIVE: To evaluate clinical efficacy of suture anchors in treating acute injuries of medial collateral ligament (MCL) of knee at degree III. METHODS: Twenty-seven patients with degree III acute MCL injuries of knee were treated with suture anchors from January 2007 to June 2011. There were 15 males and 12 females, aged from 19 to 56 (averaged 32.6) years old. The time from injury to operation was 3 to 10 days, averaged 6 days. Symptoms and physical signs before and after treatment were observed, Lysholm scoring were used to evluated clinical efficacy. RESULTS: All patients were followed up from 16 to 30 months with an average of 21.6 months. The stability of knee joints was good in all patients. Abduction stress test was negative when the knee joint was straightened at 0 degrees and flexed at 30 degrees. The average degree of flexed knee (67.00 +/- 5.80) degrees preoperatively was lower than that of postoperatively (136.50 +/- 6.30) degrees at 1 year. According to Lysholm scoring, preoperative scores ranged from 30 to 43 points, averaged 36.46 +/- 1.48; 1 year after operation ranged from 87 to 100 with an average of 91.50 +/- 3.80 and higher than postoperative. Twenty patients got an excellent results, 5 good and 2 fair. CONCLUSION: Suture anchors in treating acute injuries of medial collateral ligament of knee at degree III has following advantages: small range of tissue dissection, easy to operate, reliable fixation and less complications.

The treatment of osteoporotic thoracolumbar severe burst fractures with short pedicle screw fixation and vertebroplasty.

BACKGROUND: To investigate the clinical and radiological results of short pedicle screw fixation and vertebroplasty in osteoporotic thoracolumbar severe burst fractures. METHODS: From September 2006 to August 2010, 19 consecutive patients sustained osteoporotic thoracolumbar severe burst fractures with or without neurologic deficit and were included in this prospective study. All patients underwent short pedicle screw fixation and vertebroplasty. Segmental kyphosis, AVBHr and PVBHr, and Canal compromise were calculated on radiographs pre-operatively, post-operative and at final follow up. VAS, ODI and SF-36 were calculated pre-operatively and at final follow up. RESULTS: Mean operative time was 70.8 min (range 60~100 min) and mean blood loss was 92 ml (range 60~160 ml). The mean duration of their hospital stay was 4.5 days (range 3-7 days). The operative incisions were healing well. Average follow up time was 40.1 months (range 24~72 months). The AVBHr was corrected from preoperative (48.1 ± 6.8) % to postoperative (94.1 ± 1.7) % (P < 0.001). The PVBHr was corrected from preoperative (62.7 ± 4.8) % to postoperative (92.8 ± 1.8) % (P < 0.001). Canal compromise was corrected from preoperative (37.3 ± 5.8) % to postoperative (5.9 ± 2.3) % (P < 0.001). The segmental kyphosis was corrected from preoperative (20.6 ± 5.3) degree to postoperative (2.0 ± 3.2) degree (P < 0.001). VAS scores were reduced from preoperative 7.21 ± 0.86 to 2.21 ± 0.98 at final follow up (P < 0.001). SF-36 Bodily pain was reduced from preoperative 75.31 ± 13.85 to 13.74 ± 13.24 at final follow up (P < 0.001), and SF-36 Role Physical was reduced from preoperative 59.21 ± 26.63 to 19.74 ± 22.94 at final follow up (P < 0.001). The ODI scores were reduced from preoperative 81.68 ± 4.44 to 15.37 ± 5.54 at final follow up (P < 0.001). All 4 patients with partial neurological deficit initially had improvement. Cement leakage was observed in 3 cases (two anterior to vertebral body and one into the disc without sequela). There were no instances of instrumentation failure and no patient had persistent postoperative back pain. CONCLUSIONS: Vertebroplasty and short pedicle screw fixation has the advantages of both radiographic and functional results for treating osteoporotic thoracolumbar severe burst fractures using a purely posterior approach.

[Pedicle screw at the fracture level and vertebroplasty via paraspinal approach for the treatment of old thoracolumbar fractures].

OBJECTIVE: To investigate the feasibility and safety of the treatment for thoracolumbar fractures with pedicle screw at the fracture level and vertebroplasty via paraspinal approach. METHODS: From August 2007 to August 2010, 22 old patients with thoracolumbar fractures were treated with pedicle screw at the fracture level and vertebroplasty via paraspinal approach. There were 14 males and 8 females, ranging in age from 60 to 71 years (mean, 64.6 years). The time from injury to surgery varied from 1 to 4 d (mean,2.7 d). All the patients suffered from single thoracolumbar fractures and located at T11 in 2 cases, at T12 in 5 cases, at L1 in 11 cases and at L2 in 4 cases. According to the Denis fracture classification, there were 6 compression fractures and 16 burst fractures. The mean preoperative load-sharing classification of spine fractures was 5.4 score. The mean preoperative thoracolumbar injury classification and scoring was 5.2. Based on the ASIA neurologic grading system, preoperative neurological function was grade B in 2 cases,grade C in 3 cases, grade D in 7 cases and grade E in 10 cases. The neurological function, vertebral central and anterior height, kyphotic angle of the vertebral fractures by radiographs and visual analog scale were calculated pre-operatively, post-operatively and at the last follow-up. RESULTS: Median operating time was 60.8 min (ranged from 50 to 95 min) and median blood loss was 84 ml (ranged from 50 to 130 ml). The operative incisions were healed well. The duration of follow-up averaged 21.6 months (ranged from 12 to 48 months). The anterior vertebral body height was corrected from preoperative (52.3 +/- 10.3) % to postoperative (6.1 +/- 4.2) % and (6.8 +/- 5.4) % at the last follow-up. The central vertebral body height was corrected from preoperative (38.9 +/- 11.2) % to postoperative (8.3 +/- 4.7) % and (9.4 +/- 4.5)% at the last follow-up. The Cobbs angle of the injured vertebral segment was corrected from preoperative (19.5 +/- 9.5) degrees to postoperative (4.3 +/- 4.1) degrees and (6.2 +/- 4.7) degrees at the last follow-up. The VAS scores reduced from preoperative 8.56 +/- 0.88 to post-operative 3.48 +/- 0.91 and 3.20 +/- 0.92 at the last follow-up. The postoperative neurologic function of all 22 patients improved 1 to 2 degrees except 10 patients of grade E. There were no instances of instrumentation failure and no patient had persistent postoperative back pain. CONCLUSION: The pedicle screw at the fracture level and vertebroplasty via paraspinal approach has the advantages of less invasive and blood loss, and could prevent the development of kyphosis and offers improvement of the spinal cord function. Furthermore, it could decrease the risks of postoperative back pain and the failure of instrumentation.

[Surgical treatment of thoracolumbar fractures using reduction and short-segment pedicle screw at the fracture level with the approach through para-vertebral muscles].

OBJECTIVE: To evaluate the efficacy and clinical outcome of reduction and pedicle screws fixation at the fracture level with the approach through para-vertebral muscles in treating thoraeolumbar fractures. METHODS: From January 2007 to March 2010,27 patients with thoracolumbar fractures were treated with posterior open reduction and internal fixation with the approach through para-vertebral muscles. There were 19 males and 8 females with the mean age of 36.3 years old (ranged,21 to 57). According to Magerl type, type A2 was in 5 cases, A3 in 14, B1 in 3, B2 in 5. According to Frankel classification of spinal cord injury: grade D was in 6 cases and grade E in 21 cases. X-rays and CT scans were performed after operation. Cobb angle of the injured vertebral segment,the percentage of vertebral compression,and sagittal diameter stenosis rate of the injured spinal canal were observed by radiographic data. Neurological function was evaluated by the Frankel grade. RESULTS: All patients were followed up from 12 to 28 months with an average of 19.6 months. The percentage of vertebral compression, Cobb angle of the injured vertebral segment, spinal canal sagittal diameter stenosis rate were respectively corrected from (46.6 +/- 10.5)%, (18.3 +/- 7.2) degrees, (30.2 +/- 7.2)% to postoperative (5.2 +/- 3.7)%, (5.3 +/- 5.1) degrees, (6.3 +/- 4.2)% and (6.7 +/- 4.6)%, (7.1 +/- 3.1), (7.2 +/- 4.5)% at last follow-up. There were significant difference in above items between preoperation and postoperation (P < 0.05); and there was no significant difference in above items between postoperation and last follow-up (P > 0.05). In aspect of nerve function, 3 cases with Frankel grade D recovered to grade E. CONCLUSION: Using reduction and short-segment pedicle screws fixation at the fracture level through para-vertebral muscles approach is an effective method in treating thoracolumbar fractures. The method has advantages of simple operation,easy establishing screw, short operative time, less blood loss, which can obtain good reduction and stable, reliable fixation after operation.

[The cup safe-zone and optimum combination of the acetabular and femoral anteversions that fulfills the desired range of motion of the hip].

OBJECTIVE: To investigate safe range of acetabular prosthesis angle and the optimum combination of cup and neck in the range of activities of daily living (ADL). METHODS: A three-dimensional generic parametric and kinematic simulation module of THA was developed. Range of motion (ROM) of flexion > or = 110 degrees, internal-rotation > or = 30 degrees at 90 degrees flexion, extension > or = 30 degrees and external rotation > or = 40 degrees were defined as the normal criteria for desired ROM for activities of daily living (ADL), and ROM of flexion > or = 120 degrees, internal-rotation > or = 45 degrees at 90 degrees flexion, extension > or = 30 degrees and external rotation > or = 40 degrees as the severe criteria. The range of the changes in the general head-neck ratios (GR), the femoral neck anteversion (FA), the operative anteversion (OA) and operative inclination (OI) of the cup component were 2-2.92, 0 degrees-30 degrees, 0 degrees-70 degrees, 10 degrees-60 degrees respectively. For the collodiaphyseal angle (CCD) of 135 degrees, the corresponding OA related to the OI which every 5 degrees was calculated, and described using dots and lines in a coordinate system in which OI of acetabular cup was the horizontal ordinate and OA of acetabular cup was the vertical ordinate. All data was analyzed by SAS 6.12 software. RESULTS: Large GR greatly increased the size of safe range and it was recommended that GR be more than 2.37 when the CCD-angle was 135 degrees as it further increases the size of safezone. The size of cup safety range of the severe criteria was smaller than normal criteria. When the CCD-angle was 135 degrees, the optimum relationship between OA of acetabular and FA of the normal criteria and the severe criteria can be estimated by the formula: Y1=-0.816X1 + 39.76 (R2=0.993), Y2=-0.873X2 + 47.04 (R2=0.999) respectively. CONCLUSION: Large GR greatly increases the size of safe-zone and it is recommended that GR be more than 2.37, so it extends the acceptable range of error that clinicians cannot avoid it completely. The larger range of the hip motion, the smaller size of the cup safe-zone,but can retrieve by increase the GR. The OA is negative with FA.