Comparison of staged LLIF combined with posterior instrumented fusion with posterior instrumented fusion alone for the treatment of adult degenerative lumbar scoliosis with sagittal imbalance.

BACKGROUND: To retrospectively compare the clinical and radiological outcomes of staged lateral lumbar interbody fusion (LLIF) combined with posterior instrumented fusion(PIF)with PIF alone for the treatment of adult degenerative lumbar scoliosis (ADLS) with sagittal imbalance. METHODS: ADLS patients with sagittal imbalance underwent corrective surgery were included and divided into staged group (underwent multilevel LLIF in the first-stage and PIF in the second-stage) and control group (PIF alone). The clinical and radiological outcomes were evaluated and compared between the two groups. RESULTS: Forty-five patients with an average age of 69.7±6.3 years were enrolled, including 25 in the staged group and 20 in the control group. Compared with preoperative values, patients in both groups achieved significant improvement in terms of ODI, VAS back, VAS leg and spinopelvic parameters after surgery, which were maintained well during the follow-up period. Compared with control group, total operative time in the staged group was longer, but the amounts of blood loss and blood transfusion were reduced. The average posterior fixation segments were 6.20±1.78 in the staged group and 8.25±1.16 in the control group (P<0.01), respectively. Posterior column osteotomy (PCO) was performed in 9 patients (36%) in the staged group, while PCO and/or pedicle subtraction osteotomy were performed in 15 patients (75%) in the control group (P<0.01). There was no difference in complications between the two groups. CONCLUSION: Both surgical strategies were effective for the treatment of ADLS with sagittal imbalance. However, staged treatment was less invasive, which reduced the number of posterior fixation segments and osteotomy requirement.

Long-segment fixation VS short-segment fixation combined with kyphoplasty for osteoporotic thoracolumbar burst fracture.

BACKGROUND: To retrospectively compare clinical and radiological results of long-segment fixation (LF) and six-screw short-segment fixation combined with kyphoplasty (SSFK) for osteoporotic thoracolumbar burst fracture (OTBF). METHODS: Forty patients affected by OTBF with mean age of 61.85 years were included in this study. The mean follow-up period was 13.63 months. Twenty-four patients were treated by SSFK, and 16 patients were treated by LF. Clinical outcomes, radiological parameters and complications were assessed and compared. RESULTS: The mean operative time and blood loss were 89.71 ± 7.62 min and 143.75 ± 42.51 ml for SSFK group, respectively; 111.69 ± 12.25 min (P < 0.01) and 259.38 ± 49.05 ml (P < 0.01) for LF group, respectively. The two groups were similar in terms of preoperative radiological and clinical results. Compared with preoperative values, both groups achieved significant improvement in terms of VAS, ODI, Cobb angle and anterior vertebral body height (AVH) ratio at final follow-up. However, during the follow-up period, significant loss of Cobb angle and AVH ratio were observed for both groups. Five cases (20.83%) of asymptomatic cement leakage were observed in SSFK group. One case of implant failure and two cases of adjacent or non-adjacent vertebral fractures were observed in LF group. CONCLUSIONS: Both SSFK and LF are safe and effective for treatment of OTBF. Comparatively, SSFK is less invasive and can preserve more motion segments, which may be a more valuable surgical option in some elderly patients. A high-quality randomized controlled study is required to confirm our finding in the future.

Cadaveric biomechanical analysis of multilevel lateral lumbar interbody fusion with and without supplemental instrumentation.

BACKGROUND: This study was to evaluate and compare the biomechanical features of multilevel lateral lumbar interbody fusion (LLIF) with or without supplemental instrumentations. METHODS: Six human lumbar specimens were tested under multidirectional nondestructive moments (7.5 N·m), with a 6 degree-of-freedom spine simulator. The overall and intervertebral range of motion (ROM) were measured optoelectronically. Each specimen was tested under the following conditions at L2-5 levels: intact; stand-alone; cage supplemented with lateral plate (LP); cage supplemented with unilateral or bilateral pedicle screw/rod (UPS or BPS). RESULTS: Compared with intact condition, the overall and intersegmental ROM were significantly reduced after multilevel stand-alone LLIF. The ROM was further reduced after using LP instrumentation. In flexion-extension (FE) and axial rotation (AR), pedicle screw/rod demonstrated greater overall ROM reduction compared to LP (P < 0.01), and bilateral greater than unilateral (P < 0.01). In lateral bending (LB), BPS demonstrated greater overall ROM reduction compared to UPS and LP (P < 0.01), however, UPS and LP showed similar reduction (P = 0.245). Intervertebral ROM reductions showed similar trend as the overall ones after using different types of instrumentation. However, at L2/3 (P = 0.57) and L3/4 (P = 0.097) levels, the intervertebral ROM reductions in AR were similar between UPS and LP. CONCLUSIONS: The overall and intervertebral stability increased significantly after multilevel LLIF with or without supplemental instrumentation. BPS provided the greatest stability, followed by UPS and LP. However, in clinical practice, less invasive adjunctive fixation methods including UPS and LP may provide sufficient biomechanical stability for multilevel LLIF.

The biomechanical study of a modified lumbar interbody fusion-crenel lateral interbody fusion (CLIF): a three-dimensional finite-element analysis.

To analyze the biomechanical stability of a redesigned cage, a new lateral plate and the effect of length of cage in CLIF, an L4-L5 finite element model was performed. Six different internal fixation methods were designed and operated under six conditions (Stand-alone CLIF; CLIF with unilateral pedicle screws (CLIF + UPS); CLIF with bilateral pedicle screws (CLIF + BPS); CLIF with lateral plate (CLIF + LP); CLIF with lateral plate and unilateral pedicle screws (CLIF + LP + UPS); CLIF with lateral plate and bilateral pedicle screws (CLIF + LP + BPS)). Ranges of motion (ROM) and stress distribution were evaluated. The effect of the length of cage was analyzed. The ROMs of stand-alone CLIF group and other internal fixation groups were decreased by >90% compared with the intact group. The CLIF + LP + BPS group has the minimum ROM. The CLIF + LP group has smaller ROM than stand-alone group. The stand-alone group has the minimum stress except for extension condition. The CLIF + LP model has less ROM, but a greater stress load was observed in the lateral plate. As for the length of cage, the largest stress is located at the junction between cage and distal end plate, especially in the epiphyseal ring and cortical compact. We conduct a new 'cylinder wall theory' that the cage should be placed to cover the epiphyseal ring. We recommend the length of cage should cover the epiphyseal ring to reduce the subsidence of cage.

[Clinical and radiological results of thoracic and lumbar fracture and dislocation treated with posterior transforaminal decompression and interbody fusion].

OBJECTIVE: To evaluate the clinical and radiological results of patients with thoracic and lumbar fracture and dislocation treated by posterior transforaminal decompression and interbody fusion. METHODS: From June 2010 to June 2017, posterior transforaminal decompression, interbody fusion combined with pedicle screw fixation were performed in 21 patients with thoracic and lumbar fracture and dislocation. Their clinical and radiological data were collected and retrospectively analyzed, including 15 males and 6 females, aged from 25 to 58 years with an average of 45 years old. According to the criterion of American Spinal Injury(ASIA), preoperative neurological function was graded A in 3 cases, B in 7 cases, C in 6 cases, D in 4 cases and E in 1 case. Operative time and intraoperative blood loss and correlative complications were recorded. And VAS score, ODI and Cobb angle were evaluated before and after surgery. The improvement of neurological function was also analyzed at the final follow-up. Intervertebral bony fusion was observed during the follow-up by CT three-dimensional reconstruction. RESULTS: The operative time was 150 to 240 min with an average of (192±47) min. The intraoperative blood loss was 380 to 750 ml with an average of(603±120) ml. Dura sac tearing and cerebral fluid leakage occurred in 3 cases and were repaired during operation; superficial wound infection occurred in 1 case, and got healing after dressing change. The postoperative follow-up duration was 24 to 45 months with an average of(37.0±9.5) months. VAS score was improved from preoperative 8.9±0.4 to immediately postoperative 4.2±1.3(P<0.05). At the final follow-up, VAS score decreased further to 3.6±0.8. ODI was decreased from preoperative (95.30±3.52)% to (32.51±6.30)% at the final follow-up (P<0.05). Cobb angle was corrected from preoperative (21.2±8.8)° to immediately postoperative(2.3±3.1)° (P<0.05). At the final follow-up, Cobb angle was (3.2±2.5)°, showing no significant difference with immediately postoperative value. The neurological function was grade A in 3 cases, B in 3 cases, C in 5 cases, D in 6 cases and E in 4 cases at the final follow-up. All the patients got solid intervertebral bone fusion in 8 to 13 months after operation, with an average fusion time of (10.3±2.5) months. CONCLUSIONS: For the patients with thoracic and lumbar fracture and dislocation mainly involving intervertebral disc and endplate plane, posterior transforaminal decompression and interbody fusion not only is less invasive, but also can effectively reconstruct spinal three column and obtain good biomechanical stability. And, it is beneficial for the good recovery of neurological function.

Modified one-stage posterior/anterior combined surgery with posterior pedicle instrumentation and anterior monosegmental reconstruction for unstable Denis type B thoracolumbar burst fracture.

PURPOSE: This study aimed to evaluate the clinical and radiological results in patients with unstable Denis type B thoracolumbar burst fractures treated by modified one-stage posterior/anterior combined surgery. METHODS: Thirty-one patients with unstable Denis type B thoracolumbar burst fractures were enrolled in this study. The patients underwent one-stage posterior/anterior combined surgery with posterior instrumentation using pedicle screws and anterior monosegmental reconstruction utilizing titanium mesh cages. The mean follow-up period was 38.3 months. Clinical outcomes, radiological parameters, and treatment-related complications were assessed. RESULTS: The mean age of the patients was 36.4 years. The mean operative time and blood loss were 230 min and 645 ml, respectively. The VAS pain score was significantly improved after surgery, and the improvement was maintained until the final follow-up. In 23 patients with neurologic dysfunction, 20 (87 %) patients had improvement after surgery. By the final follow-up, 27 patients had returned to work; 18 of the 27 patients returned to a similar job. The mean sagittal kyphosis was corrected from 21.2° preoperatively to 2.5° postoperatively, which increased slightly to 4.3° at the final follow-up. Minimal subsidence and tilt of the titanium mesh cage were observed during the follow-up period. Solid bony fusion was achieved in all patients. One patient developed a posterior surgical site infection, which was resolved by antibiotic treatment and surgical debridement. CONCLUSION: Modified one-stage posterior/anterior combined surgery for Denis type B unstable thoracolumbar burst fractures can produce good clinical and radiological outcomes.

[Acetabular morphological analysis in patients with high dislocated DDH using three-dimensional surface reconstruction technique].

OBJECTIVE: To simulate acetabular morphology and perform acetabular quantitative analysis in high dislocated developmental dysplasia of the hip (DDH) patients using three-dimensional (3D) surface reconstruction technique, in order to understand the acetabular anatomic features and develop operative strategies for acetabular reconstruction. METHODS: 3D pelvic images were reconstructed by Mimics software from CT data of 13 patients (13 hips) with high developmental DDH and 13 normal persons (26 hips). True acetabular superior-inferior diameter, anterior-posterior diameter, acetabular depth, medial wall thickness, abduction angle and anteversion angle were measured and compared between the two groups of participants. RESULTS: Irregular acetabular shape was found in high dislocated group, showing a triangle with wide upper and narrow lower. The acetabular quantitative analysis revealed (38.29 +/- 2.71) mm superior-inferior diameter, (21.74 +/- 5.33) mm anterior-posterior diameter, (15.50 +/- 2.93) mm acetabular depth, (6.80 +/- 2.97) mm medial wall thickness, (49.29 +/- 7.40) degrees abduction angle and (23.82 +/- 11.21) degrees anteversion angle in high dislocated patients. The superior-inferior diameter, anterior-posterior diameter and acetabular depth of high dislocated patients were significantly smaller than those of the normal contirols (P<0.05). However, the medial wall thickness, abduction angle and anteversion angle of high dislocated patients were significantly bigger than those of the normal controls (P<0.05). CONCLUSION: 3D reconstruction technique can restore true acetabular morphology and perform quantitative analysis. Compared with normal controls, high dislocated DDH patients have acetabular features: irregular shape, lower opening, higher medial wall and bigger abduction and anteversion angles. Joint arthroplasty surgery in high dislocated DDH patients needs to look at these acetabular features.

Three-dimensional computerized preoperative planning of total hip arthroplasty with high-riding dislocation developmental dysplasia of the hip.

OBJECTIVE: To assess whether computed tomography (CT)-based 3-dimensional (3D) computerized pre-operative planning is accurate and reliable in patients with high-riding dislocation developmental dysplasia of the hip (DDH) undergoing total hip arthroplasty (THA). METHODS: Between September 2009 and February 2011, a prospective study with an inbuilt means of comparing predictive techniques in 20 patients (20 hips) with high-riding dislocation DDH was undertaken. All patients had pre- and post-operative CT scans, data from which were transferred digitally to Mimics software. 3D pre-operative planning to predict the acetabular component size, hip rotation center position and acetabular component coverage was performed using Mimics software. The results and post-operative course were compared with those of the traditional acetate templating technique. RESULTS: Using 3D computerized planning, 14/20 components (70%) were predicted exactly and 6/20 (30%) within one size, whereas with the conventional acetate templating technique, 5/20 components (25%) were predicted exactly, 9/20 (45%) within one size and 6/20 (30%) within two or more sizes. There was a strong correlation between the 3D computerized planned acetabular component size, hip rotation center distance, acetabular component host coverage and that found postoperatively. Five patients were considered to need structural bone graft on the basis of 3D computerized planning; this was highly coincident with the intraoperative findings in all five cases. CONCLUSION: CT-based 3D computerized pre-operative planning using Mimics software is an accurate and reliable technique for patients with high-riding dislocation DDH undergoing THA.

Midterm results of uncemented acetabular reconstruction for posttraumatic arthritis secondary to acetabular fracture.

At an average of 6.3 years after surgery, we evaluated midterm results of uncemented acetabular reconstruction in 31 hips with posttraumatic arthritis that developed after acetabular fracture. Patients were categorized by previous fracture treatments (open-reduction group and conservative-treatment group) and fracture patterns (simple group and complex group). Surgery duration and blood loss were greater in the open-reduction and complex groups than in the conservative-treatment and simple groups (P < .05). The mean Harris Hip Score increased from 49 before surgery to 89 after surgery. Survival with revision or radiographic acetabular loosening as an end point was 100%. Fracture treatments and patterns were associated with increased surgery duration and increased blood loss. Open reduction and internal fixation of a fracture favor anatomical restoration of the hip's rotational center.

A systematic review assessing the effectiveness of alendronate in reducing periprosthetic bone loss after cementless primary THA.

Periprosthetic bone loss, especially in the proximal part of the femur, is common after cementless total hip arthroplasty (THA). To determine the short- and long-term effect of alendronate on periprosthetic bone mineral density after THA, we conducted computerized searches for randomized, controlled trials evaluating the use of alendronate in patients treated with cementless primary THA. A review of PubMed, the Cochrane Central Register of Controlled Trials, Web of Science, and Embase from their inception to May 2010 was completed, and we assessed methodological quality and abstracted relevant data. Of 310 citations that were initially identified, 5 studies assessing 146 patients were reviewed. Those studies showed that significantly less periprosthetic bone loss had occurred in the alendronate-treated group than in the placebo-treated group during the short-term period after THA. For long-term investigation, the studies reported that the periprosthetic bone density was a bit higher in the alendronate-treated group compared to the placebo-treated group, but the differences did not reach statistical significance.This systematic review suggests that alendronate has a beneficial effect with regard to preservation of periprosthetic bone short-term after cementless THA. However, the studies could not provide enough evidence that the positive effect noted in the early postoperative period is maintained long-term. A longer follow-up with a larger number of participants is needed to confirm the outcome of cementless THA patients treated with alendronate.