Chien-Lin Liu

Is fusion necessary for surgically treated burst fractures of the thoracolumbar and lumbar spine? : A prospective, randomized study

Study Design. A prospective clinical trial was conducted. Objectives. To compare the results of fusion versus nonfusion for surgically treated burst fractures of the thoracolumbar and lumbar spine. Summary of Background Data. The operative results of surgically treated burst fractures with short segmental fixation have been well documented. There is no report comparing the results of fusion and nonfusion. Methods. Fifty-eight patients were included in this study, with the inclusion criteria as follows: neurologically intact spine with a kyphotic angle ≥20°, decreased vertebral body height ≥50% or a canal compromise ≥50%, incomplete neurologic deficit with a canal compromise <50%, complete neurologic deficit, and multilevel spinal injury or multiple traumas. All patients were randomly assigned to fusion or nonfusion groups, and operative treatment with posterior reduction and instrumentation was carried out. Posterior fusion with autogenous bone graft was performed for the fusion group (n = 30), and no fusion procedure was done for the nonfusion group (n = 28). The average follow-up period was 41 months (range, 24–71 months). Results. The average loss of kyphotic angle was not statistically significant between these 2 groups. The radiographic parameters were statistically significantly better in the nonfusion group, including angular change in the flexion-extension lateral view (4.8° vs. 1.0°), lost correction of decreased vertebral body height (3.6% vs. 8.3%), intraoperative estimated blood loss (303 mL vs. 572 mL), and operative time (162 minutes vs. 224 minutes). The scores on the low back outcome scale were not statistically significant for these 2 groups. Conclusions. The short-term results of short segmental fixation without fusion for surgically treated burst fractures of the thoracolumbar spine were satisfactory. The advantages of instrumentation without fusion are the elimination of donor site complications, saving more motion segments, and reducing blood loss and operative time.

Efficacy of dilute betadine solution irrigation in the prevention of postoperative infection of spinal surgery.

Study Design. Prospective, single-blinded, randomized study. Objectives. To evaluate the efficacy of dilute betadine irrigation of spinal surgical wounds in prevention of postoperative wound infection. Summary and background. Deep wound infection is a serious complication of spinal surgery that can jeopardize patient outcomes and increase costs. Povidoneiodine is a widely used antiseptic with bactericidal activity against a wide spectrum of pathogens, including methicillin-resistant Staphylococcus aureus. The aim of this study was to evaluate the efficacy of dilute betadine solution in the prevention of wound infection after spinal surgery. Methods. Four hundred and fourteen patients undergoing spinal surgery were randomly assigned to two groups. In group 1 (208 patients), surgical wounds were irrigated with dilute betadine solution (3.5% betadine) before wound closure. Betadine irrigation was not used in group 2 (206 patients). Otherwise, perioperative management was the same for both groups. Results. Mean length of follow-up was 15.5 months in both groups (range, 6–24 months). No wound infection occurred in group 1. One superficial infection (0.5%) and six deep infections (2.9%) occurred in group 2. The differences between the deep infection rate (P = 0.0146) and total infection rate (P = 0.0072) were significant between the two groups. Conclusions. Our report is the first prospective, single-blinded, randomized study to evaluate the clinical effectiveness of dilute betadine solution irrigation for prevention of wound infection following spinal surgery. We recommended this simple and inexpensive measure following spinal surgery, particularly in patients with accidental wound contamination, risk factors for wound infection, or undergoing surgery in the absence of routine ultraviolet light, laminar flow, and isolation suits.

Polymethylmethacrylate augmentation of pedicle screw for osteoporotic spinal surgery: a novel technique.

Study Design. A retrospective study to evaluate the clinical results of patients with osteoporosis and various spinal diseases treated surgically with polymethylmethacrylate (PMMA) augmented pedicle screw. Objective. To report a novel technique using PMMA for pedicle screw augmentation in osteoporotic spinal surgery. Summary of Background Data. Many studies have proved that the stiffness and strength of pedicle screw fixation can be significantly increased when the pedicle screw is augmented with various cements. However, most of those studies were experimental. Clinical reports using those materials for pedicle screw augmentation are rare and a practical and reliable technique for primary pedicle screw augmentation with cement has not yet been established. Methods. Forty-one patients [23 female, 18 male, mean age 75.1 (50–90) years] with osteoporosis and various spinal diseases underwent spinal decompression and instrumentation with PMMA augmentation of pedicle screw. Pre-and postoperative scores for visual analogue scale for pain and Oswestry disability index questionnaire were analyzed. The screw migration, which is the distance from the screw tip to the anterior cortex and upper endplate of vertebra, was also evaluated immediately after the operation and at the mean 22.3 months final follow-up. Results. Totally 291 of 300 screws were augmented with PMMA. There was neither neurologic deterioration nor symptomatic cement leakage after surgery. The mean visual analogue scale pain score of these patients improved from 9.2 to 1.5 (P < 0.01) and the functional Oswestry disability index score improved from 77.5% to 44.2% (P < 0.01). Kyphotic deformity was improved from average 23.2° to 11.9° after surgery, and to 14.9° at final follow-up (P < 0.01). The average loss of kyphosis correction was 3°. There was no significant screw migration when the screws distances just after operation and at the final follow-up were compared (P > 0.01). Conclusion. The presented technique of PMMA for augmentation of pedicle screw is a safe, reliable, and practical technique for osteoporotic patients who also had various spinal diseases and need spinal instrumentation.

Clinical Outcome and Imaging of Arthroscopic Single-Row and Double-Row Rotator Cuff Repair: A Prospective Randomized Trial

PURPOSE The purpose of this study was to compare the clinical and imaging outcomes of single-row and double-row suture anchor fixation in arthroscopic rotator cuff repair with emphasis on analysis of the effect of various tear size on repair integrity. METHODS Fifty-three patents were randomized to either single-row or double-row rotator cuff repair at the time of surgical intervention. The clinical results were evaluated by applying the UCLA score and the ASES index and assessing muscle strength in abduction and external rotation with a minimum 2-year follow-up. The postoperative rotator cuff integrity was evaluated by magnetic resonance arthrography at 6-month and minimum 2-year follow-up. RESULTS We enrolled 27 patients in the single-row group and 26 patients in the double-row group. Statistically, the UCLA score; the ASES index; and muscle strength were significantly increased in both groups after surgery, but there was no significant difference between the 2 groups. At minimum 2-year follow-up, intact rotator cuffs were found in 17 patients in the single-row group and 20 in the double-row group, based on magnetic resonance arthrography results. Overall, there was no significant difference in postoperative structural integrity between the 2 groups at 6-month and 2-year follow-up. In patients with tear size larger than 3 cm, the muscle strength of the shoulder was significantly better in the double-row group. For the final imaging results, regardless of the tear size, there was no difference between the single-row and double-row groups. CONCLUSIONS Arthroscopic rotator cuff repair with double-row fixation showed better shoulder strength in patients with larger tear size (>3 cm) in comparison with single-row fixation. However, the imaging results showed no significant difference in cuff integrity in both groups in patients with any tear size at 6-month and minimum 2-year follow-up. LEVEL OF EVIDENCE Level II, lesser-quality randomized control trial.

Tuberculous Spondylitis and Pyogenic Spondylitis : Comparative Magnetic Resonance Imaging Features

Study Design. We retrospectively compared magnetic resonance images (MRIs) of tuberculous (TB) spondylitis and pyogenic spondylitis. Objective. To identify differences between the diseases. Summary of Background Data. Clinical and imaging findings of the 2 diseases are hard to distinguish. MRI may show important differences and aid in early diagnosis and treatment. Methods. We compared 22 MRI parameters in 33 patients with TB spondylitis (average age, 66 years) and in 33 patients with pyogenic spondylitis (average age, 65 years). Results. Seventeen parameters significantly differed between the groups. The most important were local and heterogeneous enhancement of the vertebral body in all patients with TB spondylitis, diffuse and homogeneous enhancement of the vertebral body in 94% of patients with pyogenic spondylitis, vertebral intraosseous abscess with rim enhancement (TB vs. pyogenic, 79% vs. 0%), disc abscess with rim enhancement (9% vs. 64%), and well-defined paraspinal abnormal signal intensity (82% vs. 18%). Conclusions. Most parameters occurred in both diseases. Distinctive findings were a pattern of bone destruction with relative disc preservation and heterogeneous enhancement for TB spondylitis and a diskitis pattern (disc destruction) with peridiscal bone destruction and homogeneous enhancement for pyogenic spondylitis. These MRI parameters may facilitate the differential diagnosis of these diseases.

Can povidone-iodine solution be used safely in a spinal surgery?

Intra-operative incidental contamination of surgical wounds is not rare. Povidone-iodine solution can be used to disinfect surgical wounds. Although povidone-iodine is a good broad-spectrum disinfecting agent, it has occasionally been reported to have a negative effect on wound healing and bone union. Therefore, its safety in a spinal surgery is unclear. A prospective, single-blinded, randomized study was accordingly conducted to evaluate the safety of povidone-iodine solution in spinal surgeries. Ascertained herein was the effect of wound irrigation with diluted povidone-iodine solution on wound healing, infection rate, fusion status and clinical outcome of spinal surgeries. Materials and methods: From January 2002 to August 2003, 244 consecutive cases undergoing primary instrumented lumbosacral posterolateral fusion due to degenerative spinal disorder with segmental instability had been collected and randomly divided into two groups: the study group (120 cases, 212 fusion levels) and the control group (124 cases, 223 fusion levels). Excluded were those patients with a prior spinal surgery, spinal trauma, malignant tumor, infectious spondylitis, rheumatoid arthritis, ankylosing spondylitis, metabolic bone disease, skeletal immaturity or with an immunosuppressive treatment. In the former group, wounds were irrigated with 0.35% povidone-iodine solution followed by normal saline solution just before the bone-grafting and instrumentation procedure. However, only with normal saline solution in the latter. All the operations were done by the same surgeon with a standard technique. All the patients were treated in the same postoperative fashion as well. Later on, wound healing, infection rate, spinal bone fusion and clinical outcome were evaluated in both groups. Results: A significant improvement of back and leg pain scores, modified Japanese Orthopedic Association function scores (JOA) and ambulatory capacity have been observed in both groups. One hundred and seven patients in the study group and one hundred and nine in the control group achieved solid union. There was no infection in the study group but six deep infections in the control group. Wound dehiscence was noted in one group 1 and two group 2 patients. A subsequent statistical analysis revealed higher infection rate in the control group (P<0.05), but no significant difference in fusion rate, wound healing, improvement of pain score, function score and ambulatory capacity between the two groups. Conclusion: Diluted povidone-iodine solution can be used safely in spinal surgeries, and it will not influence wound healing, bone union and clinical outcome.

Subsequent vertebral fracture after vertebroplasty: incidence and analysis of risk factors.

Study Design. A retrospective review and analysis of consecutive patients who underwent single-level vertebroplasty at our institute between March 2002 and March 2006. Objective. To analyze the risk factors for subsequent fractures after vertebroplasty and to predict the postoperative fracture-free time and rate. The effect of bone cement volume injected was also evaluated. Summary of Background Data. Previous studies of subsequent fractures after vertebroplasty showed conflicting conclusions about risk factors. The frequency of refracture also varied, ranging from 12% to 52%. Most new fractures occurred at adjacent levels, with different risk factors identified. No data were available on the effect of injected bone cement volume, and no consensus had been reached as to the optimal cement volume. Methods. All enrolled patients were treated with single-level vertebroplasty and followed a standardized postoperative care protocol. Data from medical records and radiographs were collected and analyzed. Variables included patient constitutional factors, radiographic parameters, and volume of injected bone cement. Results. A total of 166 patients (76 men, 90 women) with a mean age of 73.4 years were enrolled in this study. The mean follow-up time was 15.3 months. The overall refracture rate was 38%, with a mean fracture-free interval of 32 months. Both a greater volume of bone cement injected and a greater degree of vertebral height restored contributed significantly to the risk of subsequent adjacent fracture. No risk factor for subsequent remote fracture was identified. A greater volume of bone cement injected was positively correlated with deformity correction after vertebroplasty. Conclusion. Most subsequent fractures occurred at the adjacent level within the first 3 months. Patient preoperative condition did not help predict refracture. Although a greater volume of bone cement injected when performing vertebroplasty contributed to the risk of subsequent adjacent fracture, it resulted in a greater improvement of kyphosis.

Candidemia in cancer patients: Impact of early removal of non-tunneled central venous catheters on outcome

OBJECTIVE To explore the impact of retention of non-tunneled central venous catheters (CVCs) on survival in candidemic cancer patients, where CVCs are commonly used and essential. A second object was to determine whether early CVC removal would benefit a subset of cancer patients. METHODS We retrospectively evaluated 92 cancer patients who had a single, non-tunneled CVC in place. Patients were grouped according to CVC retention or removal; the later group was subdivided into early (CVC removed <or=72h after candidemia onset) and late removal. A Cox regression model was used for determining risk factors of adverse outcome and Kaplan-Meier analyses for comparing in-hospital 3-30 day survival among subgroups. RESULTS Baseline characteristics were comparable between CVC retention (n=20) or removal (n=72) groups. CVC retention was a significant risk factor of poor outcome, independent of other significant prognostic host factors (hazard ratio 7.15, 95% confidence interval 3.51-14.53, p<0.001). Patients of early CVC removal (n=40) had significant better survival than those of late removal (n=32) (p<0.001). CONCLUSION The results suggest that retention of CVCs has a negative impact on survival in candidemic cancer patients, and that early CVC removal should be considered in a subset of cancer patients with candidemia.

Posterior instrumentation reduces differences in spine stability as a result of different cage orientations: an in vitro study.

Study Design. A multisegmental cadaveric spine model was used to quantify the load-displacement behavior of intact spine specimens, specimens injured and stabilized using Bagby and Kuslich (BAK) cages as lumbar interbody fusion devices with or without posterior instrumentation across two levels. Objectives. To compare the stabilities imparted by the cages placed using an oblique and conventional posterior approaches and to determine the effects of supplementary posterior instrumentation. Summary of Background Data. The BAK cage as posterior lumbar interbody fusion (PLIF) has been used to restore disc height, reduce morbidity, provide immediate stability to the patients, and enhance fusion rates. The obliquely inserted BAK cage has the advantages of reducing exposure and precise implantation. The biomechanical efficacy of this procedure is sparse, especially in comparison to the PLIF with and without posterior instrumentation. Methods. Nine fresh human ligamentous spines (L2–S1) were affixed within a testing frame for determining their load-displacement behaviors. Load testing in clinically relevant modes was performed sequentially for the intact and the following procedures across the L4–S1 segment: posterior destabilization, stabilization using two parallel BAK cages (CBAK group) or one oblique BAK cage (OBAK group), further stabilization with posterior instrumentation, and finally cyclic loading in flexion-extension. Spatial positions of the LEDs attached to vertebral bodies were recorded using a three-dimensional motion measurement system. Results. When used alone to restore stability, the orientation of the cage affected the outcome. In flexion OBAK orientation and in extension CBAK orientation provided better stability (decrease in motion with respect to intact case), compared with the other orientation. In lateral bending, CBAK orientation was found to be better than OBAK. In axial mode, CBAK orientation was effective in both directions while OBAK was effective only in right axial rotation. With the supplementary posterior fixation, the differences in stability resulting from the orientations were not noticeable at all, both before and after cyclic tests. Conclusions. Owing to the differences in the surgical approach and the amount of dissection, the stability for the cages when used alone as a function of cage orientation was different. These subtle differences were reduced by the use of posterior fixation device, underscoring the importance of using instrumentation when cages are used as PLIFs. However, the oblique insertion may be more favorable since it requires less exposure, enables precise implantation, and is less expensive, especially when used with supplementary instrumentation.

Biomechanical analysis of the disc adjacent to posterolateral fusion with laminectomy in lumbar spine.

Objectives: After posterolateral fusion with laminectomy for the degenerative lumbar spine, accelerated degeneration of the disc adjacent to the fusion mass has been clinically observed. Previous studies used a finite element model (FEM) to calculate the stress of the adjacent disc in the fused lumbar spine with spinal fixator and bone graft. However, little emphasis was placed on the simultaneous spinal fusion and decompression procedure. To investigate if the spinal decompression procedure in posterolateral fusion would increase stress significantly, the FEM was employed to estimate the stress concentration of the disc above the fusion mass in posterolateral fusion with laminectomy and hemilaminectomy. Methods: Three FEMs of the lumbar spine were established: intact spine, posterolateral fusion with total laminectomy, and posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments). The posterolateral fusion added spinal fixator and bone graft between the transverse process. The L1 vertebral body was subjected to 10-Nm flexion, extension, torsion, and lateral bending. The bottom of the L5 vertebral body was fixed. Results: In flexion, the stress on the adjacent disc in posterolateral fusion with laminectomy and hemilaminectomy respectively increased 90% and 21% over that of the intact spine. In posterolateral fusion with hemilaminectomy, the supraspinous and interspinous ligaments shared some external forces to alleviate the stress concentration of the adjacent disc. However, in extension, torsion, and lateral bending, these two fusion models had almost no change in range of motion and stress of adjacent disc. Conclusion: Posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments) was able to alleviate the stress concentration of the disc above the fusion mass in flexion.