Circumferential Reconstruction of Subaxial Cervical and Cervicothoracic Spine by Simultaneously Combined Anterior-posterior Approaches in the Sitting Position.

OBJECTIVE: To introduce and analyze the feasibility of a new surgical strategy for circumferential reconstruction of subaxial cervical and cervicothoracic spine by simultaneously combined anterior-posterior approach in the sitting position. METHODS: A retrospective review was performed for seven patients who underwent the above surgical procedure between July 2011 and January 2015. Among the seven patients, there were six men and one woman, with an average age of 52 years (range, 36-79 years). Six patients were confirmed to have a lower subaxial cervical fracture and dislocation with a locked facet joint, and the other patient had an invasive tumor involving both anterior and posterior parts of vertebrae and lamina, detected by radiological examination. The levels involved for all patients were from C4 to T2 . According to American Spinal Injury Association (ASIA) classification, one case was class A, four were class B, and two were class D. The patients were restricted in the sitting position with traction and a halo in extension to immobilize the head during the operation. The simultaneously combined anterior-posterior operation for reduction, decompression or tumor resection and circumferential reconstruction was carried out. RESULTS: Both anterior and posterior procedures were successfully completed simultaneously in the sitting position in all cases. There were no perioperative complications. The average operative time was 175 ± 32 min (range, 120-240 min), and the mean blood loss was 430 ± 85 mL (range, 200-1100 mL). The patients were followed up for 35.8 months (range, 18-60 months). The symptom of neck pain improved distinctly and no evidence of implant failure was noted in any patients. Neurological status improvement was confirmed in six patients, who had suffered incomplete paralysis. The ASIA grade improved in five patients, and two cases had no change in grade. CONCLUSIONS: The "sitting position" simultaneously combined anterior-posterior approach is safe and is superior to the traditional prone position and supine position, and the surgical results are satisfactory.

[Insertion technique and clinical application of regional method axis pedicle screw].

OBJECTIVE: To explore the clinical efficacies and outcomes of regional method axis pedicle screw insertion technique. METHODS: During the period of April 2004 to June 2010, a total of 23 cases with traumatic instability of upper cervical vertebrae were recruited. There were 19 males and 4 females with a mean age of 45.8 years. They underwent surgical operations after an excellent traction reduction of cervical vertebrae. The entry points were drawn on axial facet joint and all of them distributed in the region of upper inner 1/4 of lower articular process. So the regional method was employed to determine the entry point. All subjects underwent the reconstruction of posterior stability. Axial pedicle screws were inserted by the insertion technique of axial pedicle screw via the "regional method". The entry region was in the upper inner 1/4 area of lower articular process. The entry angle, medial inclination and superior inclination were determined by the direction of inner wall and upper wall of isthmus. Postoperative cervical radiography and CT examination were performed to confirm the screw position. RESULTS: Forty-six axial pedicle screws were implanted. No significant complications occurred. All screws stayed in excellent positions without the invasion of vertebral artery and spinal canal. CONCLUSIONS: The "regional method" insertion technique of axial pedicle screw require no memory of complex entry points and entry angle parameters. And there is no need of identifying the anatomical landmarks. Thus this approach is accurate, safe and suitable for most patients.

Methotrexate-mediated inhibition of RAD51 expression and homologous recombination in cancer cells.

BACKGROUND: Methotrexate is an inhibitor of folic acid metabolism. Homologous recombination is one of the most important ways to repair double-stranded breaks in DNA and influence the radio- and chemosensitivity of tumor cells. But the relationship between methotrexate and homologous recombination repair has not been elucidated. METHODS: Induction of double-strand breaks by methotrexate in HOS cells is assessed by the neutral comet assay. Inhibition of subnuclear repair foci by methotrexate is measured by immunofluorescence. Western blot and quantitative real-time PCR are conducted to detect whether methotrexate affects the expression level of genes involved in homologous recombination. In addition, we used a pCMV3xnls-I-SceI construct to determine whether methotrexate directly inhibits the process of homologous recombinational repair in cells, and the sensitivity to methotrexate in the Ku80-deficient cells is detected using clonogenic survival assays. RESULTS: The result showed that methotrexate can regulate the repair of DNA double-strand breaks after radiation exposure, and methotrexate inhibition caused the complete inhibition of subnuclear repair foci in response to ionizing radiation. Mechanistic investigation revealed that methotrexate led to a significant reduction in the transcription of RAD51 genes. Treatment with methotrexate resulted in a decreased ability to perform homology-directed repair of I-SceI-induced chromosome breaks. In addition, enhancement of cell death was observed in Ku mutant cells compared to wild-type cells. CONCLUSIONS: These results demonstrate that methotrexate can affect homologous recombination repair of DNA double-strand breaks by controlling the expression of homologous recombination-related genes and suppressing the proper assembly of homologous recombination-directed subnuclear foci.

[Lateral position one-stage combined posteroanterior approaches for the treatment of lumbosacral tuberculous spondylitis].

OBJECTIVE: To investigate the feasibility of a one-stage combined posteroanterior approaches for the treatment of lumbosacral tuberculous spondylitis with the patients lying in a lateral position. METHODS: A retrospective review was conducted for 15 patients with lumbosacral tuberculosis undergoing one-stage combined posteroanterior approaches for radical lesion resection and reconstruction. All patients were observed and evaluated by clinical and imaging studies. RESULTS: Operative posture:11 cases for right side and 4 cases for left side. The mean operative duration was 280 min (range: 230 - 380 min) and the mean estimated volume of blood loss 1720 ml (range: 1100 - 3000 ml). Imaging results: No recurrence of tuberculose focus was found until the last follow-up. Upon image reviewing, it showed no loosening or displacement except for two cases of slightly collapsed titanium mesh. Preoperative and postoperative changes in the degree of lumbar lordosis were statistically significant [(20 ± 5)° vs (31 ± 5)°, P < 0.05]. The Kirkaldy-Willis classification rating yielded satisfactory results for 13 cases. CONCLUSION: The patients with lumbosacral tuberculosis undergoing one-stage combined posteroanterior approaches may achieve radical lesion resection, posteroanterior collaboration and reconstruction. It avoids a 2-stage operation, eliminates the need of changing a patient's body position with secondary sterilization and shortens the operative duration. Lumbosacral surgery for tuberculosis combines the respective advantages of anterior, posterior and combined posteroanterior approaches and yet makes up for their deficiencies.

Assessing validation of dual fluoroscopic image matching method for measurement of in vivo spine kinematics.

BACKGROUND: Accurate knowledge of the spinal structural functions is critical to understand the biomechanical factors that affect spinal pathology. Many studies have investigated the human vertebral motion both in vitro and in vivo. However, determination of in vivo motion of the vertebrae under physiologic loading conditions remains a challenge in biomedical engineering because of the limitations of current technology and the complicated anatomy of the spine. METHODS: For in vitro validation, a human lumbar specimen was imbedded with steel beads and moved to a known distance by an universal testing machine (UTM). The dual fluoroscopic system was used to capture the spine motion and reproduce the moving distance. For in vivo validation, a living subject moved the spine in various positions while bearing weight. The fluoroscopes were used to reproduce the in vivo spine positions 5 times. The standard deviations in translation and orientation of the five measurements were used to evaluate the repeatability of technique. The accuracy of vertebral outline matching with metallic marks matching technology was compared. RESULTS: The translation positions of the human lumbar specimen could be determined with a mean accuracy less than 0.35 mm and a mean repeatability 0.36 mm for the image matching technique. The repeatability of the method in reproducing in vivo human spine six degrees of freedom (6DOF) kinematics was less than 0.43 mm in translation and less than 0.65° in rotation. The accuracy of metallic marks and vertebral outline matching did not show significant difference. CONCLUSIONS: Combining a dual fluoroscopic and computerized tomography imaging technique was accurate and reproduceable for noninvasive measurement of spine vertebral motion. The vertebral outline matching technique could be a useful technique for matching of vertebral positions and orientations which can evaluate and improve the efficacy of the various surgical treatments.

[Effect of intervertebral position on range of motion after artificial lumbar total disc replacement and clinical management].

OBJECTIVE: To discuss the effect of SB Charité lumbar artificial disc position on intervertebral range of motion (ROM) and clinical management. METHODS: Between 2004 and 2007, 30 discogenic low back pain patients confirmed by discography underwent 1/2-level total disc replacement (TDR) implantation with 32 prostheses. There were 12 males and 18 females with a mean age of 44 years old (range: 28-55). All indexed levels were inserted between L4-S1 involving L4-5 (n = 9), L5S1 (n = 19) and L4-S1 (n = 2). The clinical outcome was measured by Oswestry disability index (ODI) and visual analogue scale (VAS). Radiographic outcome measures included flexion/extension ROM, restoration of operative level intervertebral disc height, maintenance of disc height at the final follow-up. A technique previously described by McAfee was used to evaluate TDR position in three groups. Paired t test was used to compare the preoperative and postoperative ROM and clinical ODI, VAS scores. RESULTS: Twenty-eight patients were followed-up for 24-60 months with an average of 38 months. All the prostheses were solidly immobilized with the vertebral endplate. No disc prosthesis rupture, dislocation, subsidence or heterotopic ossification was observed. Preoperative ODI, VAS back pain and VAS leg pain scores were 70.34 ± 9.21, 7.46 ± 2.65, 4.81 ± 2.75;and postoperative corresponding scores 7.65 ± 8.61, 0.68 ± 0.69, 0.35 ± 0.32 respectively. The positions of disc prostheses were graded as Group I, excellent, n = 17; Group II, suboptimal, n = 6; Group III, poor, n = 5. Preoperative mean intervertebral flexion/extension ROM (degree) of Group I to Group III were 9.75 ± 2.80, 10.30 ± 1.20 and 10.08 ± 2.43 respectively. The postoperative mean intervertebral flexion/extension ROM (degree): 6.68 ± 3.83, 4.22 ± 3.51 and 3.48 ± 3.56 respectively. Postoperatively all clinical outcome scores were lower than preoperative ones. Disc height was significantly restored. Mean intervertebral ROM decreased versus preoperative. Although there was a tendency of mean intervertebral ROM increasing with a better disc position, no statistical difference was observed. CONCLUSION: The mid-term clinical outcome of TDR is generally satisfactory. The TDR position influences intervertebral ROM to some extent. Efficient clinical management can reduce prosthetic malposition.

[Mini-invasive extraperitoneal approach for anterior lumbar surgery].

OBJECTIVE: To study a mini-invasive extraperitoneal approach to lumbar spine and discuss its exposure technique, complications and management. METHOD: Anterior lumbar surgery was performed in 52 patients via the mini-invasive anterior extraperitoneal approach. Diagnoses included lumbar degenerative instability (n=23), discogenic lumbar pain (n=25), lumbosacral congenital deformity (n=2) and revision after posterior laminectomy & discectomy (n=2). The patients underwent anterior lumbar interbody fusion (n=32) and total disk replacement (n=20). The operated disks included L(4-5) and L5-S1. There were single level (n=47) and double level (n=5). Operation time, blood loss, perioperative complications, postoperative bed-leaving time, incision length, pain of abdomen incision and postoperative hospitalization duration were recorded in details. RESULTS: All cases were exposed clearly and no one needed to prolong incision or change operation for an insufficient exposure. Average operation time was 85 min, average blood loss 155 ml, average postoperative bed-leaving time 3 days and average incision length 6.5 cm. All cases felt very little pain of abdominal incision and postoperative hospitalization duration was 7-10 days. Perioperative complications included vena cava tear (n=1), peritoneum tear (n=2), postoperative abdominal distention (n=3) and postoperative fever (n=5). No retrograde ejaculation was found in all male cases. CONCLUSION: The technique of mini-invasive extraperitoneal approach to anterior lumbar has such multiple advantages as fewer complications, less trauma, excellent exposure to anterior vertebrae and disk and without destruction of posterior spinal component