Dasheng Lin

Artificial disk replacement combined with midlevel ACDF versus multilevel fusion for cervical disk disease involving 3 levels.

The optimal surgical approach for cervical disk disease remains a matter of debate, especially for multilevel disease. The purpose of this study was to compare the results of 2 surgical strategies for cervical disk disease involving 3 levels: hybrid constructs, artificial disk replacement combined with midlevel anterior cervical diskectomy and fusion (ACDF), and 3-level ACDF. The authors prospectively compared patients who had cervical disk disease involving 3 levels that was treated with hybrid constructs or with 3-level ACDF. Patients were asked to use the Neck Disability Index (NDI) to grade their pain intensity preoperatively and at routine postoperative intervals of 1, 3, 6, 12, and 24 months. Dynamic flexion and extension lateral cervical radiographs were obtained while in the standing position preoperatively and at the postoperative intervals. The angular range of motion for C2-C7 and the adjacent segments was measured using the Cobb method. Twenty-four patients were treated, 12 with hybrid constructs and 12 with 3-level ACDF. Both groups had significant postoperative improvement in NDI scores and neck pain (P<.05). However, no significant difference was found between the groups (P>.05). The hybrid constructs group showed faster recovery of C2-C7 range of motion. Mean C2-C7 range of motion of the hybrid constructs group recovered to that of the preoperative value, but that of the 3-level ACDF group did not (P<.05). Range of motion of the superior and inferior adjacent segments showed significant differences between the 2 groups at 12 and 24 months postoperatively (P<.05). These findings suggest that the hybrid constructs is a safe and effective alternative for cervical disk disease involving 3 levels. The definite stabilization and maintained range of motion can be achieved right away, which can ensure a good preliminary clinical outcome.

Anterior versus posterior approach for four-level cervical spondylotic myelopathy.

The purpose of this study was to compare the results of 2 surgical strategies for 4-level cervical spondylotic myelopathy: a hybrid procedure using anterior cervical diskectomy and fusion (ACDF) combined with segmental corpectomy versus posterior laminectomy and fixation. Between 2002 and 2010, fifty-one patients with consecutive 4-level cervical spondylotic myelopathy were treated surgically, with 27 patients undergoing the hybrid procedure and 24 undergoing posterior laminectomy and fixation. Radiologic data were compared between the 2 groups, including cervical curvature and cervical range of motion (ROM) in the sagittal plane. Pre- and postoperative neurological status was evaluated using the Japanese Orthopaedic Association (JOA) scoring system and the Nurick grading system. Mean ROM at last follow-up was not significantly different between the 2 groups (P>.05). In the hybrid group, mean JOA score and Nurick grade improved from 9.6±1.4 and 2.74±0.45 respectively, preoperatively, to 13.9±1.3 and 0.86±0.38 respectively, postoperatively. In the fixation group, mean JOA score and Nurick grade improved from 9.4±1.2 and 2.81±0.42 respectively, preoperatively, to 13.1±1.5 and 1.32±0.36 respectively, postoperatively. The JOA scores and Nurick grades at last follow-up were significantly different between the 2 groups (P<.05). In patients with preoperative cervical kyphosis, preoperative JOA score and Nurick grade were not significantly different between the 2 groups (P>.05); however, JOA scores and Nurick grades at last follow-up showed better improvement in the hybrid group than in the fixation group (P<.01). In patients with preoperative cervical lordosis, the preoperative and last follow-up JOA score and Nurick grade were not significantly different between the 2 groups (P>.05).

Minimally Invasive Plating Osteosynthesis for Mid-distal Third Humeral Shaft Fractures

Mid-distal third humeral shaft fractures can be effectively treated with minimally invasive plating osteosynthesis and intramedullary nailing (IMN). However, these 2 treatments have not been adequately compared. Forty-seven patients (47 fractures) with mid-distal third humeral shaft fractures were randomly allocated to undergo either minimally invasive plating osteosynthesis (n=24) or IMN (n=23). The 2 groups were similar in terms of fracture patterns, fracture location, age, and associated injuries. Intraoperative measurements included blood loss and operative time. Clinical outcome measurements included fracture healing, radial nerve recovery, and elbow and shoulder discomfort. Radiographic measurements included fracture alignment, time to healing, delayed union, and nonunion. Functional outcome was satisfactory in both groups. Mean American Shoulder and Elbow Surgeons score and Mayo score were both better for the minimally invasive plating osteosynthesis group than for the IMN group (98.2 vs 97.6, respectively, and 93.5 vs 94.1, respectively; P<.001). Operative time was shorter and less intraoperative blood loss occurred in the minimally invasive plating osteosynthesis group than in the IMN group. Average time to union was similar in both groups. Primary union was achieved in 23 of 24 patients in the minimally invasive plating osteosynthesis group and in 22 of 23 in the IMN group. Minimally invasive plating osteosynthesis may have outcomes comparable with IMN for the management of mid-distal third humeral shaft fractures. Minimally invasive plating osteosynthesis is more suitable for complex fractures, especially for radial protection and motion recovery of adjacent joints, compared with IMN for simple fractures.

Proximal Femoral Locking Plate With Cannulated Screws for the Treatment of Femoral Neck Fractures

The purpose of this study was to evaluate the efficacy and safety of the proximal femoral locking plate with cannulated screws for the treatment of femoral neck fractures. A prospective study was performed in 41 patients with femoral neck fractures treated with a proximal femoral locking plate with cannulated screws between January 2005 and December 2008. Twenty-five men and 16 women had a mean age of 47 years (range, 21-65 years). The time from injury to surgery ranged from 2 hours to 7 days. Three patients had a Garden type I fracture, 9 a type II, 18 a type III and 11 a type IV. Operative time, intraoperative blood loss, fracture healing time, Harris Hip Score for hip function, and complications were recorded to evaluate treatment effects.Mean operative time was 63.6 minutes (range, 40-90 minutes), with mean intraoperative blood loss of 84.2 mL (range, 50-200 mL). Mean time to union was 15.5 weeks (range, 12-36 weeks). Two patients (Garden type III and type IV) did not achieve union, and 4 patients (1 Garden type III and 3 type IV) had avascular necrosis of the femoral head. In patients with nonunion, 1 (Garden type III) underwent intertrochanteric osteotomy, and the other underwent total hip replacement (THR). In patients with avascular necrosis, 2 required THR and the others (1 Garden type III) required no further surgery. Twenty-six (63%) patients had excellent results, 8 (20%) had good results, 3 (7%) had moderate results, and 4 (10%) had poor results. These findings suggest that the proximal femoral locking plate with cannulated screws for the treatment of femoral neck fractures is effective and results in fewer complications, especially for Garden type I, II, and III fractures.

Cervical ossification of the posterior longitudinal ligament: Anterior versus posterior approach

Background: The optimal approach to provide satisfactory decompression and minimize complications for ossification of the posterior longitudinal ligament (OPLL) involving multiple levels (3 levels or more) remains controversial. The purpose of this study was to compare the results of two surgical approaches for cervical OPLL involving multiple levels; anterior direct decompression and fixation, and posterior indirect decompression and fixation. We present a retrospective review of 56 cases followed at a single Institution. Materials and Methods: We compared patients of multiple levels cervical OPLL that were treated at a single institution either with anterior direct decompression and fixation or with posterior indirect decompression and fixation. The clinical records of the patients with a minimum duration of follow-up of 2 years were reviewed. The associated complications were recorded. Results: Fifty-six patients constitute the clinical material. 26 cases were treated by anterior corpectomy and fixation and 30 cases received posterior laminectomy and fixation. The two populations were similar. It was found that both anterior and posterior decompression and fixation can achieve satisfactory outcomes, and posterior surgery was accomplished in a shorter period of time with lesser blood loss. Although patients had comparable preoperative Japanese Orthopaedics Association (JOA) scores, those with a canal occupancy by OPLL more than 50% and managed anteriorly had better outcomes. However, for those with more severe stenosis, anterior approach was more difficult and associated with higher risks and complications. Despite its limitations in patients with high occupancy OPLLs, through the multiple level laminectomy, posterior fixation can achieve effective decompression, maintaining or restoring stability of the cervical spine, and thereby improving neural outcome and preventing the progression of OPLL. Conclusions: The posterior indirect decompression and fixation has now been adopted as the primary treatment for cervical OPLL involving multiple levels with the canal occupancy by OPLL <50% at our institution because this approach leads to significantly less implant failures. Those patients with the occupancy ≥50% managed with anterior approach surgeries had better outcomes, but approach was more difficult and associated with higher risk and complications.

Rapamycin-induced autophagy activity promotes bone fracture healing in rats

Autophagy is a crucial mediating process for normal bone cell function and metabolism in physiology or pathology. Rapamycin has been demonstrated to induce the autophagy pathway by inhibiting the mammalian target of rapamycin (mTOR) pathway. However, the contribution of autophagy in orthopedic diseases is rarely reported. The aim of the present study was to evaluate the capacity of pharmacologically induced autophagy to modify disease function in a rat model of bone fracture. A femur fracture model was established via surgery in adult male Sprague-Dawley rats. Rapamycin (n=63 rats) or dimethyl sulfoxide (DMSO) vehicle control (n=63 rats) was administered intraperitoneally for 2, 4 and 6 weeks, and 21 randomly selected rats were sacrificed in each group at each time point. X-ray micro-computed tomography and hematoxylin and eosin staining were used to evaluate the extent of fracture healing in each group. The effects of rapamycin on autophagy, mTOR signaling and the expression levels of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) were analyzed using immunohistochemistry, immunofluorescence staining and western blot analysis. Rapamycin affected the mTOR signaling pathway in rats following fracture, as indicated by the inhibition of the phosphorylation of ribosomal protein S6, a target of mTOR, and activation of microtubule-associated protein 2 light chain 3, a key marker of autophagy. Histomorphometry and image examination indicated that the number of osteoblasts in each section was significantly (P<0.01) increased in the rapamycin group compared with the control group, and this was associated with a significant (P<0.05) increase in mineralized callus fraction. Furthermore, rapamycin treatment increased the expression levels of VEGF and PCNA in the rat callus tissue. These results suggest that rapamycin may serve a beneficial function in fracture healing, and that the underlying mechanism may involve the activation of autophagy.

Bone fracture in a rat femoral fracture model is associated with the activation of autophagy

Autophagy, which is a mechanism for the turnover of intracellular molecules and organelles, protects cells during stress responses; however, the role of autophagy in the stages of bone fracture remains to be elucidated. The aim of the present study was to investigate the process of autophagy in bone tissue at different time-points after fracture. A femur fracture model was established in male adult Wistar rats via surgery. The protein expression of microtubule-associated protein II light chain 3 (LC3-II) was analyzed in a femur fracture (experimental) group and a sham-surgery group using immunofluorescence. The protein expression of proliferating cell nuclear antigen (PCNA) was used to investigate the cell proliferation in bone tissue following fracture via immunohistochemical analysis. The correlation between cell proliferation and autophagy was analyzed using linear regression. LC3-II protein was constitutively expressed in the sham-surgery group; however, compared with the expression in the sham-surgery group, the LC3-II expression in the experimental group was significantly increased at each time-point (P<0.05). Similarly, immunohistochemistry revealed that the number of PCNA-positive cells in each section was significantly increased following fracture injury (P<0.01). A comparison of the LC3-II- and PCNA-positive rates in the experimental group rats at each time-point revealed a linear correlation (R2=0.43, P<0.01). In conclusion, surgically induced fracture in rats is associated with an increase in LC3-II and PCNA protein expression during the initial stages of fracture injury, and a correlation exists between the expression of the two proteins. These results suggest that potential treatment aimed at improving fracture healing should target the process of autophagy.

Treatment of neglected femoral neck fractures using the modified dynamic hip screw with autogenous bone and bone morphogenetic protein-2 composite materials grafting

Background: The neglected femoral neck fracture is one where there has been a delay of more than 30 days to seek medical help from the time of the original injury. Salvage procedures, such as osteotomy and other treatment options such as vascularized and nonvascularized bone grafts have high failure rates and arthroplasty procedures are not ideal, given the patients young age and higher levels of activity. We designed a hollow bone graft dynamic hip screw (Hb-DHS) (modified DHS, Hb-DHS) for use in neglected femoral neck fractures. This study evaluates the efficacy and safety of the modified dynamic hip screw (DHS) with autogenous bone and bone morphogenetic protein 2 (BMP-2) composite materials grafting for the treatment of the neglected femoral neck fractures. Materials and Methods: A prospective study was carried out in twenty patients of neglected femoral neck fractures treated with the modified DHS with autogenous bone and BMP-2 composite materials grafting between July 2007 and February 2010. There were 14 men and 6 women with a mean age of 29.6 years (range 19–42 years). The mean time from injury to surgery was 9.7 weeks (range 6–16 weeks). The operation time, intraoperative blood loss, fracture healing time, Harris scoring for hip function and complications were recorded to evaluate treatment effects. Results: The mean operation time was 75.8 min (range 55–100 min) with mean intraoperative blood loss volume of 105 mL (range 70–220 mL). The mean time to union was 17 weeks (range 12–24 weeks). One patient did not achieve union, and two patients had avascular necrosis of the femoral head. This patient with nonunion underwent intertrochanteric osteotomy. In patients with avascular necrosis one required total hip arthroplasty, the other did not require intervention at the last followup. A total of 14 patients (70%) had excellent results, 2 (10%) had good, 1 (5%) had moderate and 3 (15%) had poor results. Conclusion: The modified DHS with autogenous bone and BMP-2 composite materials grafting for the treatment of neglected femoral neck fractures waseffective and had less complications.

Effect of Bone Cement Volume Fraction on Adjacent Vertebral Fractures after Unilateral Percutaneous Kyphoplasty.

Study Design: A retrospective study. Summary of Background Data: Complications of the bone cement used in vertebroplasty and kyphoplasty procedures have received increasingly more attention, especially for bone cement volume. Objective: The aim of the study was to retrospectively assess the relationship between bone cement volume fraction and adjacent vertebral fracture (AVF) after unilateral percutaneous kyphoplasty (PKP). Materials and Methods: Between 2006 and 2011, 495 patients with single-level osteoporotic vertebral compression fracture (OVCF) were surgically treated by unilateral PKP and had completed 12-month follow-up in our hospital. According to the new OVCF, they were divided into 3 groups: AVF group, non-AVF group, and normal group (who were not new OVCF). On the basis of the value of the plain radiography, the cement volume fraction for the vertebral body was calculated, and cement leakage, bone mineral density, visual analog scale, and Cobb angle of preoperative and postoperative were analyzed. Results: During the follow-up, 110 (22.2%) patients had new OVCF, and others were normal (n=385). Fifty-two cases were AVF and 58 were non-AVF. The cement volume fraction of AVF group, non-AVF group, and normal group were 32.5%±5.5%, 27.3%±1.8%, and 27.1%±2.6%, respectively. The 95% confidence interval of volume fraction were (31.0, 34.1), (26.8, 27.7), and (26.9, 28.5), respectively. The AVF group showed higher cement volume fraction in 3 groups (P<0.05), and there were no significant difference between non-AVF and normal group (P>0.05). There were 19 (36.5%) patients with cement leakage in AVF group, 12 (20.7%) in non-AVF group, and 68 (17.7%) in normal group. The AVF group showed higher cement leakage (P<0.05). Compared with AVF group and normal group, non-AVF group had lower bone mineral density in preoperation. All groups reported significantly improved visual analog scale scores and Cobb angle on the day of surgery. However, there were no significant difference between the 3 groups. Conclusions: Unilateral PKP is an effective and safe procedure for patients with OVCF. However, cement volume should be determined in terms of the vertebral body fraction to obtain a favorable outcome. The risk of AVF and cement leakage will increase obviously with the cement volume fraction increased. We recommend that a bone cement volume fraction of about one fourth is suitable for unilateral PKP.

Pediatric physeal slide-traction plate fixation for comminuted distal femur fractures in children.

Background: Operative stabilization without inhibiting epiphyseal growth of pediatric comminuted distal femur fractures presents specific challenges. The purpose of this study was to evaluate the clinical efficacy of pediatric physeal slide-traction plate (PPSP) fixation for comminuted distal femur fractures in children. Methods: We prospectively followed 16 children who were managed PPSP for the treatment of comminuted distal femur fractures between 2005 and 2009. There were 9 boys with a mean age of 10.4 years (range, 8 to 14 y) and 7 girls with a mean age of 9.9 years (range, 6 to 12 y). The mean follow-up was 36.4 months (range, 18 to 54 mo). Results: There were no intraoperative complications related to this technology. All patients were healed, and the mean time was 10.1 weeks (range, 8 to 13 wk). X-ray analysis of the injured limb revealed that the PPSP could be extended as the femur grew, with a mean sliding length of 5.6 mm (range, 3 to 15 mm). All patients had excellent final outcomes, and had the plates removed with no noted complications except 1 patient who had valgus malalignment of 10 degrees at 6 months after the plate removal, which was of no clinical concern and required no intervention. Conclusions: These findings suggest that PPSP is a safe and effective treatment for children with comminuted distal femur fractures that can be extended as the epiphyseal plate grows with reliable internal fixation. Level of Evidence: Therapeutic level IV.