Changes in Disc Height as a Prognostic Factor in Patients Undergoing Microscopic Discectomy.

OBJECTIVE: Some patients with disc herniation who underwent discectomy complain of back pain after surgery and are unsatisfied with the surgical results. This study aimed to evaluate the relationship between preoperative disc height (DH), postoperative DH, and pain score 12 months after surgery in patients who underwent microdiscectomy for herniated lumbar disc. METHODS: This study enrolled patients who underwent microdiscectomy at a medical center between January 2012 and December 2020. Patients with X-ray or computed tomography and pain score assessment (visual analog scale score) prior to surgery, immediately post-op, and at 1, 6, and 12 months after surgery were included. The DH index was defined as DH/overlying vertebral width. The DH ratio was defined as the postoperative DH/preoperative DH. Simple linear regression and multivariate linear regression analyses were applied to assess the correlation between DHs and leg pain scores 12 months after surgery. RESULTS: A total of 118 patients who underwent microdiscectomy were included. DH decreased up to 12 months after surgery. The DH ratio at 1, 6, and 12 months after discectomy showed a significant positive correlation with the pain scores at 12 months after discectomy (1 month : p=0.045, B=0.52; 6 months : p=0.008, B=0.78; 12 months : p=0.005, B=0.69). Multivariate linear regression analysis revealed that the level of surgery, sex, age, and body mass index had no significant relationship with back pain scores after 12 months. CONCLUSION: In patients who underwent microdiscectomy, the DH ratios at 1, 6, and 12 months after surgery were prognostic factors for back pain scores at 12 months after surgery. Aggressive discectomy is recommended for lower postoperative DH ratios and Visual analog scale scores, leading to improved patient satisfaction.

Efficacy of 3D-Printed Titanium Mesh-Type Patient-Specific Implant for Cranioplasty.

OBJECTIVE: Autologous bone grafting for cranioplasty is associated with a high infection rate and bone absorption. Synthetic implant materials for cranioplasty have been developed. In this study, we evaluated the efficacy of titanium mesh-type patient-specific implants (PSIs) for patients with skull defects using the dice similarity coefficient (DSC), clinical outcomes, and artifacts caused by implants. METHODS: This retrospective study included 40 patients who underwent cranioplasty with a titanium mesh PSI at our institution. Based on preoperative and postoperative computed tomography scans, we calculated DSC and artifacts. RESULTS: The calculated DSC of 40 patients was 0.75, and the noise was 13.89% higher in the region of interest (ROI) near the implanted side (average, 7.64 hounsfield unit [HU]±2.62) than in the normal bone (average, 6.72 HU±2.35). However, the image signal-to-noise ratio did not significantly differ between the ROI near the implanted side (4.77±1.78) and normal bone (4.97±1.88). The patients showed no significant perioperative complications that required a secondary operation. CONCLUSION: Titanium mesh-type PSIs for cranioplasty have excellent DSC values with lower artifacts and complication rates.

Biomechanical analysis of a newly developed interspinous process device conjunction with interbody cage based on a finite element model.

PURPOSE: This study aimed to investigate the biomechanical effects of a newly developed interspinous process device (IPD), called TAU. This device was compared with another IPD (SPIRE) and the pedicle screw fixation (PSF) technique at the surgical and adjacent levels of the lumbar spine. MATERIALS AND METHODS: A three-dimensional finite element model analysis of the L1-S1 segments was performed to assess the biomechanical effects of the proposed IPD combined with an interbody cage. Three surgical models-two IPD models (TAU and SPIRE) and one PSF model-were developed. The biomechanical effects, such as range of motion (ROM), intradiscal pressure (IDP), disc stress, and facet loads during extension were analyzed at surgical (L3-L4) and adjacent levels (L2-L3 and L4-L5). The study analyzed biomechanical parameters assuming that the implants were perfectly fused with the lumbar spine. RESULTS: The TAU model resulted in a 45%, 49%, 65%, and 51% decrease in the ROM at the surgical level in flexion, extension, lateral bending, and axial rotation, respectively, when compared to the intact model. Compared to the SPIRE model, TAU demonstrated advantages in stabilizing the surgical level, in all directions. In addition, the TAU model increased IDP at the L2-L3 and L4-L5 levels by 118.0% and 78.5% in flexion, 92.6% and 65.5% in extension, 84.4% and 82.3% in lateral bending, and 125.8% and 218.8% in axial rotation, respectively. Further, the TAU model exhibited less compensation at adjacent levels than the PSF model in terms of ROM, IDP, disc stress, and facet loads, which may lower the incidence of the adjacent segment disease (ASD). CONCLUSION: The TAU model demonstrated more stabilization at the surgical level than SPIRE but less stabilization than the PSF model. Further, the TAU model demonstrated less compensation at adjacent levels than the PSF model, which may lower the incidence of ASD in the long term. The TAU device can be used as an alternative system for treating degenerative lumbar disease while maintaining the physiological properties of the lumbar spine and minimizing the degeneration of adjacent segments.

Relationship between the atlantodental interval and T1 slope after atlantoaxial fusion in patients with rheumatoid arthritis.

BACKGROUND: Atlantoaxial fusion has been widely used for the treatment of atlantoaxial instability (AAI). However, atlantoaxial fusion sacrifices the motion of atlantoaxial articulation, and postoperative loss of cervical lordosis and aggravation of cervical kyphosis are observed. We investigated various factors under the hypothesis that the atlantodental interval (ADI) and T1 slope may be associated with sagittal alignment after atlantoaxial fusion in patients with rheumatoid arthritis (RA). METHODS: We retrospectively investigated 64 patients with RA who underwent atlantoaxial fusion due to AAI. Radiological factors, including the ADI, T1 slope, Oc-C2 angle, cervical sagittal vertical axis, and C2-C7 angle, were measured before and after surgery. RESULTS: The various factors associated with atlantoaxial fusion before and after surgery were compared according to the upper and lower preoperative ADIs. There was a significant difference in the T1 slope 1 year after surgery (p = 0.044) among the patients with lower preoperative ADI values. The multivariate logistic regression analysis showed that the preoperative ADI (> 7.92 mm) defined in the receiver-operating characteristic curve analysis was an independent predictive factor for the increase in the T1 slope 1 year after atlantoaxial fusion (odds ratio, 4.59; 95% confidence interval, 1.34-15.73; p = 0.015). CONCLUSION: We found an association between the preoperative ADI and difference in the T1 slope after atlantoaxial fusion in the patients with RA. A preoperative ADI (> 7.92 mm) was an independent predictor for the increase in the T1 slope after atlantoaxial fusion. Therefore, performing surgical treatment when the ADI is low would lead to better cervical sagittal alignment.

Interspinous Process Fixation Device Versus Extended Pedicle Screw Fixation for Symptomatic Adjacent Segment Disease: 3-Year Retrospective Study.

OBJECTIVE: In the present study, we compared the clinical and radiographic outcomes of an interspinous process fixation device (IFD) with those of extended pedicle screw fixation (PSF) for symptomatic adjacent segment disease (ASD) after lumbar fusion. METHODS: The data from 109 patients with ASD treated with IFD (n = 48) or extended PSF (n = 61) from January 2009 to January 2016 were reviewed retrospectively. The clinical outcomes were measured using a visual analog scale (VAS) and the Oswestry disability index. The radiographic outcomes included the fusion rate, incidence of cage subsidence, and additional radiographic ASD. RESULTS: The mean incision length, operative time, blood loss, and length of hospital stay were significantly lower in the IFD group (P < 0.001). Postoperative back and leg pain were relieved in both groups (P < 0.001). The mean preoperative VAS scores were 8.3 ± 1.3 and 8.5 ± 1.1 in the IFD and PSF groups and had improved to 2.8 ± 1.1 and 2.7 ± 1.2 after 36 months, respectively (P < 0.001). At 36 months postoperatively, 10 of the 56 patients (17.9%) in the PSF group had developed additional radiographic ASD compared with 2 of 44 patients (4.5%) in the IFD group. CONCLUSION: Our results have demonstrated that in the treatment of symptomatic ASD, comparable clinical and radiologic outcomes can be achieved using IFD, which has a shorter skin incision, shorter operative time, less intraoperative blood loss, and shorter hospital stay than the extended PSF technique. Although not statistically significant, the IFD resulted in a lower ASD incidence compare with the PSF technique. Thus, IFD might be an alternative surgical method for symptomatic ASD after lumbar spine fusion.

Risk Factors of Secondary Lumbar Discectomy of a Herniated Lumbar Disc after Lumbar Discectomy.

OBJECTIVE: To study risk factors of secondary lumbar discectomy (LD) for recurrent herniated lumbar disc (HLD) and identify methods to lower the rate of recurrence. METHODS: Data from 160 patients who underwent primary LD were collected retrospectively. Demographic features, radiologic findings including Pfirrmann disc degeneration, and surgical information were analyzed to compare risks between revision and non-revision patients. RESULTS: The revision rate was 15% (24 patients), and the mean follow-up was 28.3 months. HLD recurrence was not related to any demographic characteristics. Primary and secondary LD were most common at the L4-5 level, but the level of operation was not significantly associated with revision. Primary LD most commonly had a Pfirrmann disc degeneration grade of 3, followed by 4. For recurrent HLD, Pfirrmann grade 4 was most common and was statistically significant (p<0.05). A body mass index (BMI) over 30 was considered obese and was significantly related with HLD revision (p<0.05). CONCLUSION: Patients with high BMI or severe disc degeneration should be informed of HLD revision.

Upper Cervical Subluxation and Cervicomedullary Junction Compression in Patients with Rheumatoid Arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is known to involve the cervical spine up to 86%. It often causes cervical instability like atlantoaxial subluxation (AAS), subaxial subluxation, and vertical subluxation (VS). In order to find the relation between RA and cord compression, we will evaluate the characteristics and risk factors of basilar invagination (BI) and cervicomedullary junction (CMJ) compression. METHODS: From January 2007 to May 2015, 12667 patients administrated to Hanyang University Medical Center. Four thousand three hundred eighty-six patients took cervical X-ray and 250 patients took cervical computed tomography or magnetic resonance imaging. Radiologic parameters, medication records were obtained from 242 patients. Multivariate logistic regression analysis was performed with correlation of CMJ compression, basin-dental interval (BDI), basin-posterior axial line interval (BAI), pannus formation, BI, and AAS. RESULTS: In the point of CMJ compression, atlantodental interval (ADI), posterior-atlantodental interval, BAI, AAS, and BI are relatively highly correlated. Patients with BI have 82 times strong possibility of radiologic confirmed CMJ compression, while AAS has 6-fold and pannus formation has the 3-fold possibility. Compared to the low incidence of BI, AAS and pannus formation have more proportion in CMJ compression. Furthermore, wrist joint erosion was correlated with VS and AAS. CONCLUSION: BI has a very strong possibility of CMJ compression, while AAS and pannus formation have a high proportion in CMJ compression. Hence bilateral wrist joint erosion can be used as an indicator for the timing of screening test for cervical involvement. We suggest the early recommendation of cervical spine examination for the diagnosis of cervical involvement in order to prevent morbidity and mortality.

Modified Glasgow Coma Scale Using Serum Factors as a Prognostic Model in Traumatic Brain Injury.

BACKGROUND: Traumatic brain injury (TBI) is a major cause of death and disability. This study evaluated a possible relationship between serum factors at admission and the outcome of TBI. We propose a statistically validated scale for patients with TBI that combines serum factors and the Glasgow Coma Scale (GCS). METHODS: Between May 2011 and July 2016, 219 patients underwent decompressive craniectomy for TBI. We assessed laboratory data on admission, and correlations with GSC and Glasgow Outcome Scale were investigated. The modified GCS was developed from a multivariable logistic regression model, which was validated with the backward stepwise method. RESULTS: Of 219 patients with TBI enrolled in our study, 175 were men (79.9%) and 44 were women (20.1%) with a mean age of 49.1 ± 11.5 years. Initial serum values of hemoglobin, platelets, prothrombin time, and lactate dehydrogenase were associated with in-hospital mortality. The factor score was derived by adding the following points: hemoglobin (≥13.0 g/dL = 0, <13.0 g/dL = 1), platelets (≥150 × 103/mm3 = 0, <150 × 103/mm3 = 1), prothrombin time (<13.2 seconds = 0, ≥13.2 seconds = 1), and lactate dehydrogenase (<271 U/L = 0, ≥271 U/L = 1). The modified GCS score (GCS score [range, 6-15] - FS [range, 0-4]) was calculated. CONCLUSIONS: The modified GCS score using serum factors extended the information provided about patient outcomes to be comparable to more complex methods. The modified GCS score may be useful to predict in-hospital mortality in patients with TBI.

Medial Branch Block Versus Vertebroplasty for 1-Level Osteoporotic Vertebral Compression Fracture: 2-Year Retrospective Study.

OBJECTIVE: Percutaneous vertebroplasty (VP) and medial branch block (MBB) are used to treat osteoporotic vertebral compression fractures (VCF). We compared the clinical outcomes, radiologic changes, and economic results of MBB with those of VP in treating osteoporotic VCFs. METHODS: A total of 164 patients with 1-level osteoporotic VCF were reviewed retrospectively. The clinical outcomes were measured with a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). To compare economic costs between groups, total hospital costs at the last follow-up day were calculated. RESULTS: The patients were divided into 2 groups: 72 patients in the conservative group treated by MBB (MBB group) and 92 patients in the group who underwent VP (VP group). The VAS and ODI scores improved significantly within postoperative week 1 in the VP group compared with the MBB group. However, the VAS and ODI scores did not differ between the groups after 1 postoperative year. After 2 years of follow-up, 14 new fractures occurred in the VP group and 3 in the MBB group. The improvement in compression ratio was statistically greater in the VP group than in the MBB group. However, after 2 years the radiologic changes between groups did not differ statistically. After the final follow-up visits, the hospital costs were significantly lower in the MBB group. CONCLUSIONS: After 2 years of follow-up, VP and MBB both had similar efficacy in terms of pain relief and radiologic changes. MBB was more cost effective than VP. Thus, MBB alone can be a possible alternative to VP in patients with 1-level osteoporotic VCFs.

Impact of brain atrophy on 90-day functional outcome after moderate-volume basal ganglia hemorrhage.

This study aimed to evaluate the effect of brain atrophy on the functional outcome of patients with moderate-volume basal ganglia hemorrhage. Of 1003 patients with spontaneous intracerebral hemorrhage, 124 with moderate-volume basal ganglia hemorrhage (hematoma volume of 20-50 mL) were enrolled. The intercaudate distance (ICD) and sylvian fissure ratio (SFR) were used as linear brain atrophy parameters. The patients were divided into groups with favorable and unfavorable outcomes, according to the Glasgow Outcome Scale score, 90 days after symptom onset. Demographic and radiographic features, including the ICD and SFR, were compared between the two groups. Among the 124 patients, 74 (59.7%) exhibited a favorable outcome. The ICD and SFR values were significantly greater for the favorable group than for the unfavorable group. Multivariate analysis indicated that young age, high Glasgow Coma Scale score at admission, small hematoma volume, and increased ICD (odds ratio [OR], 1.207; 95% confidence interval [CI], 1.004-1.451) and SFR (OR, 1.046; 95% CI, 1.007-1.086, per 0.001) values had a beneficial effect on functional outcome. In conclusion, brain atrophy exhibits protective effects in patients with moderate-volume basal ganglia hemorrhage, and is an important factor for predicting functional outcome.

The Effects of Clinical Factors and Retro-Odontoid Soft Tissue Thickness on Atlantoaxial Instability in Patients with Rheumatoid Arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is an autoimmune disease that often occurs in the atlantoaxial segment of the cervical spine and results in instability that can cause severe pain and neurologic symptoms. Thickening of soft tissue posterior to the odontoid process of the atlantoaxial segment is referred to as retro-odontoid soft tissue (ROST) thickness or pseudotumor. The mechanism of ROST thickness is still unknown. METHODS: Among patients diagnosed with RA, those with cervical radiographs and magnetic resonance imaging records were selected for investigation of their clinical symptoms, laboratory findings, radiologic evaluation, and RA medication history. RESULTS: A total of 199 patients were selected and divided into lower and upper median groups according to the ROST thickness value. In patients with RA, the median ROST thickness value was 2.3 mm (interquartile range, 1.4-3.4). The median value of the anterior atlanto-dens interval (ADI) was 2.4 mm, with a significant difference being observed between the lower and upper median ROST thickness groups (P = 0.001). Multivariable linear regression analysis revealed a correlation between Steinbrocker stage and the positivity of rheumatoid factor. For each unit increase in the Steinbrocker stage, the ROST thickness increased by 0.35 mm (ß, -0.349; 95% confidence interval -0.643 to -0.055; P = 0.020). For every 1-mm increase in the ADI, ROST thickness decreased by 0.16 mm (ß, -0.163; 95% confidence interval -0.264 to -0.062; P = 0.002). CONCLUSIONS: This study showed a statistical correlation between ROST thickness and ADI related to biomechanical changes in the dynamic atlantoaxial segment, thereby suggesting the value of a prospective study.

Comparison of Transarticular Screw Fixation and C1 Lateral Mass-C2 Pedicle Screw Fixation in Patients with Rheumatoid Arthritis with Atlantoaxial Instability.

BACKGROUND: Many surgical procedures have been introduced to manage atlantoaxial instability caused by rheumatoid arthritis (RA) to prevent complications and improve fusion rate. We report the surgical outcome between transarticular screw fixation (TAF) and C1 lateral mass-C2 pedicle screw fixation (C1LM-C2P) in patients with atlantoaxial instability from RA. METHODS: Between 2002 and 2012, 58 patients were enrolled in the study. According to surgical procedures, patients were divided into 2 groups: group I who received TAF (n = 33) and group II who received C1LM-C2P (n = 25). Bony fusion was assessed by radiologic comparison immediately after the operation and 1 year postoperatively. In addition, complications and clinical and functional outcomes were evaluated. RESULTS: Overall, bone fusion was achieved in 32 patients in group I (97%). In group II, the fusion rate was evaluated in 100% of patients. Complications (regardless of neurologic deterioration) were cable loosening and screw malposition in group I and violation into the vertebral canal and spinal canal in group II. There was no statistical significance in fusion rate, clinical outcomes, or complications. The 12-month atlantodental interval after operation for the C1LM-C2P group was significantly lower than that for the TAF group after adjusting for all variables. CONCLUSIONS: Two surgical techniques showed a good fusion rate by rigid fixation in the immediate postoperative period and fewer surgery-related complications in patients with RA. Because surgical complications are more likely during the learning curve (as with other surgical techniques), surgeons should carefully evaluate patients before surgery by radiologic and neurologic examinations.

Factors That Predict Risk of Cervical Instability in Rheumatoid Arthritis Patients.

STUDY DESIGN: Retrospective data analysis. OBJECTIVE: To identify factors affecting the atlantodental interval, the Ranawat value, and subaxial translation after rheumatoid arthritis (RA) diagnosis. In addition, factors predictive for cervical spine instability (CSI) development after RA diagnosis were examined. SUMMARY OF BACKGROUND DATA: Development of CSI affects the prognosis and mortality of RA patients. Previous studies described that obesity is associated with reduced radiographic joint damage in RA patients. We hypothesized that body mass index (BMI) is also associated with radiographic cervical damage in RA patients. METHODS: Cervical radiographs were taken at full flexion, neutral position, and full extension to measure the geometric length of the anterior atlantodental interval, the Ranawat value, and subaxial translation. These values were entered into multivariable linear regression analysis based on potential associated factors. Hazard ratios were calculated to identify independent factors predictive of CSI. RESULTS: Of the patients diagnosed with RA between January 2005 and August 2015, 1611 who underwent at least one cervical radiograph were included. After adjusting for sex, age, BMI category, CSI, rheumatoid factor, and RA medication, multivariate analysis revealed that the risk of atlantoaxial subluxation in the underweight and normal BMI groups was about 1.6-fold (hazard ratio, 1.63; 95% CI, 1.10-2.43; P = 0.015) and 1.7-fold higher, respectively, than that in the obese group, and that the risk of vertical subluxation was about 2.5-fold (hazard ratio, 2.52; 95% CI, 1.32-4.83; P = 0.005) higher in the underweight group than in the obese group. We also found that the rheumatoid factor positivity was a predictive risk factor for CSI development. CONCLUSION: We identified risk factors predictive for CSI occurrence after RA diagnosis through cervical radiograph assessment. We found that BMI was an independent predictor for development of CSI. Further large-scale prospective studies are required to confirm these findings. LEVEL OF EVIDENCE: 3.

Risk Factors for the Development and Progression of Atlantoaxial Subluxation in Surgically Treated Rheumatoid Arthritis Patients, Considering the Time Interval between Rheumatoid Arthritis Diagnosis and Surgery.

OBJECTIVE: Rheumatoid arthritis (RA) is a systemic disease that can affect the cervical spine, especially the atlantoaxial region. The present study evaluated the risk factors for atlantoaxial subluxation (AAS) development and progression in patients who have undergone surgical treatment. METHODS: We retrospectively analyzed the data of 62 patients with RA and surgically treated AAS between 2002 and 2015. Additionally, we identified 62 patients as controls using propensity score matching of sex and age among 12667 RA patients from a rheumatology registry between 2007 and 2015. We extracted patient data, including sex, age at diagnosis, age at surgery, disease duration, radiographic hand joint changes, and history of methotrexate use, and laboratory data, including presence of rheumatoid factor and the C-reactive protein (CRP) level. RESULTS: The mean patient age at diagnosis was 38.0 years. The mean time interval between RA diagnosis and AAS surgery was 13.6±7.0 years. The risk factors for surgically treated AAS development were the serum CRP level (p=0.005) and radiographic hand joint erosion (p=0.009). The risk factors for AAS progression were a short time interval between RA diagnosis and radiographic hand joint erosion (p<0.001) and young age at RA diagnosis (p=0.04). CONCLUSION: The CRP level at RA diagnosis and a short time interval between RA diagnosis and radiographic hand joint erosion might be risk factors for surgically treated AAS development in RA patients. Additionally, a short time interval between RA diagnosis and radiographic hand joint erosion and young age at RA diagnosis might be risk factors for AAS progression.

Comparison of Endovascular Treatments of Ruptured Dissecting Aneurysms of the Intracranial Internal Carotid Artery and Vertebral Artery with a Review of the Literature.

OBJECTIVE: Subarachnoid hemorrhage (SAH) caused by rupture of an internal carotid artery (ICA) or vertebral artery (VA) dissecting aneuryesm is rare. Various treatment strategies have been used for ruptured intracranial dissections. The purpose of this study is to compare the clinical and angiographic characteristics and outcomes of endovascular treatment for ruptured dissecting aneurysms of the intracranial ICA and VA. METHODS: The authors retrospectively reviewed a series of patients with SAH caused by ruptured intracranial ICA and VA dissecting aneurysms from March 2009 to April 2014. The relevant demographic and angiographic data were collected, categorized and analyzed with respect to the outcome. RESULTS: Fifteen patients were identified (6 ICAs and 9 VAs). The percentage of patients showing unfavorable initial clinical condition and a history of hypertension was higher in the VA group. The initial aneurysm detection rate and the percentage of fusiform aneurysms were higher in the VA group. In the ICA group, all patients were treated with double stent-assisted coiling, and showed favorable outcomes. In the VA group, 2 patients were treated with double stent-assisted coiling and 7 with endovascular trapping. Two patients died and 1 patient developed severe disability. CONCLUSION: Clinically, grave initial clinical condition and hypertension were more frequent in the VA group. Angiographically, bleb-like aneurysms were more frequent in the ICA group and fusiform aneurysms were more frequent in the VA group. Endovascular treatment of these aneurysms is feasible and the result is acceptable in most instances.

Effect of Using Local Intrawound Vancomycin Powder in Addition to Intravenous Antibiotics in Posterior Lumbar Surgery: Midterm Result in a Single-Center Study.

OBJECTIVE: We conducted this study to report the efficacy of local application of vancomycin powder in the setting of surgical site infection (SSI) of posterior lumbar surgical procedures and to figure out risk factors of SSIs. METHODS: From February 2013 to December 2013, SSI rates following 275 posterior lumbar surgeries of which intrawound vancomycin powder was used in combination with intravenous antibiotics (Vanco group) were assessed. Compared with 296 posterior lumbar procedures with intravenous antibiotic only group from February 2012 to December 2012 (non-Vanco group), various infection rates were assessed. Univariate and multivariate analysis to figure out risk factors of infection among Vanco group were done. RESULTS: Statistically significant reduction of SSI in Vanco group (5.5%) from non-Vanco group (10.5%) was confirmed (p=0.028). Mean follow-up period was 8 months. Rate of acute staphylococcal SSIs reduced statistically significantly to 4% compared to 7.4% of non-Vanco group (p=0.041). Deep staphylococcal infection decreased to 2 compared to 8 and deep methicillin-resistant Staphylococcus aureus infection also decreased to 1 compared to 5 in non-Vanco group. No systemic complication was observed. Statistically significant risk factors associated with SSI were diabetes mellitus, history of cardiovascular disease, length of hospital stay, number of instrumented level and history of previous surgery. CONCLUSION: In this series of 571 patients, intrawound vancomycin powder usage resulted in significant decrease in SSI rates in our posterior lumbar surgical procedures. Patients at high risk of infection are highly recommended as a candidate for this technique.

Effects of a Temperature-Sensitive, Anti-Adhesive Agent on the Reduction of Adhesion in a Rabbit Laminectomy Model.

OBJECTIVE: A common cause of failure in laminectomy surgery is when epidural, peridural, or perineural adhesion occurs postoperatively. The purpose of this study is to examine the efficacy of a temperature-sensitive, anti-adhesive agent (TSAA agent), Guardix-SG®, as a mechanical barrier for the prevention or reduction of peridural scar adhesion in a rabbit laminectomy model. METHODS: Twenty-six mature rabbits were used for this study. Each rabbit underwent two separate laminectomies at lumbar vertebrae L3 and L6, left empty (the control group) and applied 2 mL of the TSAA agent (the experimental group), respectively. Invasive scar formation or inflammation after laminectomy was quantitatively evaluated by measuring the thickness of the dura, the distance from the surface of dura to the scar tissues, the number of inflammatory cells in the scar tissues at the laminectomy site, and the concentration of collagen in histological sections. RESULTS: At 6 weeks postsurgery, the dura was significantly thinner and the distance from the surface of dura to the scar tissues was greater in the experimental group than in the control group (p=0.04 and p=0.01). The number of inflammatory cells was not significantly different in the two groups (p=0.08), although the mean number of inflammatory cells was relatively lower in the experimental group than in the control group. CONCLUSION: The current study suggests that the TSAA agent, Guardix-SG®, could be useful as an interpositional physical barrier after laminectomy for the prevention or reduction of adhesion.

Evaluation of the Efficacy of Titanium Mesh Cages with Posterior C1 Lateral Mass and C2 Pedicle Screw Fixation in Patients with Atlantoaxial Instability.

BACKGROUND: Atlantoaxial fusion is a surgical technique that is performed for the treatment of atlantoaxial instability. The standard surgical procedure is fixation of the atlantoaxial complex via a C1 lateral mass and C2 pedicle screw with posterior wiring. Bone grafting material may still be biomechanically suboptimal, such as autologous bone obtained from osteoporotic patients, and may result in collapse and loosening of posterior wiring. METHODS: Fourteen patients with C1 lateral mass and C2 pedicle fixation as a result of atlantoaxial instability were included in this study. All patients were treated by a single surgeon using a titanium mesh cage with demineralized bone matrix packing. Patient clinical history, imaging data, and medical records were reviewed. To evaluate bony fusion, measurement of the atlantodental interval and computed tomography were performed in the preoperative period, immediate postoperative period, and at 1, 3, 6, and 12 months postoperatively. The Wilcoxon signed-rank test was used to compare differences in the radiologic evaluation at 1 and 12 months postoperatively. RESULTS: Bone fusion was achieved in all patients (100%). Of the 14 patients, 11 had rheumatoid arthritis and 3 had trauma. The mean atlantodental interval of patients with rheumatoid arthritis was 1.85 mm in the immediate postoperative period, 1.96 mm at 1 month postoperatively, 1.98 mm at 3 months postoperatively, 1.96 mm at 6 months, and 1.93 mm at 12 months. Hardware failure and other complications were not observed. CONCLUSIONS: The titanium mesh cage has several advantages compared with bone autografts, including reduced donor-site morbidity, immediate rigid fixation, and successful bone fusion.

Unilateral C1 Lateral Mass and C2 Pedicle Screw Fixation for Atlantoaxial Instability in Rheumatoid Arthritis Patients: Comparison with the Bilateral Method.

OBJECTIVE: Bilateral C1 lateral mass and C2 pedicle screw fixation (C1LM-C2P) is an ideal technique for correcting atlantoaxial instability (AAI). However, the inevitable situation of vertebral artery injury or unfavorable bone structure may necessitate the use of unilateral C1LM-C2P. This study compares the fusion rates of the C1 lateral mass and C2 pedicle screw in the unilateral and bilateral methods. METHODS: Over five years, C1LM-C2P was performed in 25 patients with AAI in our institute. Preoperative studies including cervical X-ray, three-dimensional computed tomography (CT), CT angiogram, and magnetic resonance imaging were performed. To evaluate bony fusion, measurements of the atlanto-dental interval (ADI) and CT scans were performed in the preoperative period, immediate postoperative period, and postoperatively at 1, 3, 6, and 12 months. RESULTS: Unilateral C1LM-C2P was performed in 11 patients (44%). The need to perform unilateral C1LM-C2P was due to anomalous course of the vertebral artery in eight patients (73%) and severe degenerative arthritis in three patients (27%). The mean ADI in the bilateral group was 2.09 mm in the immediate postoperative period and 1.75 mm in 12-months postoperatively. The mean ADI in the unilateral group was 1.82 mm in the immediate postoperative period and 1.91 mm in 12-months postoperatively. Comparison of ADI measurements showed no significant differences in either group (p=0.893), and the fusion rate was 100% in both groups. CONCLUSION: Although bilateral C1LM-C2P is effective for AAI from a biomechanical perspective, unilateral screw fixation is a useful alternative in patients with anatomical variations.

Prognostic role of copeptin after stroke: A systematic review and meta-analysis of observational studies.

Copeptin, the C-terminal part of provasopressin, has emerged as a novel prognostic marker after hemorrhagic or ischemic stroke. The aim of this study was to quantitatively assess the prognostic significance of plasma copeptin level on functional outcome and mortality in patients with acute stroke using a meta-analysis of the available evidence. Thirteen relevant studies from 2,746 patients were finally included in our study. An elevated plasma copeptin level was associated with an increased risk of unfavorable outcome and mortality after stroke (OR 1.77; 95% CI, 1.44-2.19 and OR 3.90; 95% CI 3.07-4.95, respectively). The result of the pooled measure on standardized mean difference (SMD) was that plasma copeptin levels were found to be significantly higher in patients who died compared to survivors (SMD 1.70; 95% CI, 1.36-2.03). A stratified analysis by study region showed significant differences in SMD of copeptin, and the heterogeneity among studies was significantly decreased. However, the positive association of copeptin with poor prognosis after stroke was consistent in each stratified analysis. The present meta-analysis suggests that early measurement of plasma copeptin could provide better prognostic information about functional outcome and mortality in patients with acute stroke.