Comparison of the Clinical Efficacy of Anabolic Agents and Bisphosphonates in the Patients With Osteoporotic Vertebral Fracture: Systematic Review and Meta-analysis of Randomized Controlled Trials

Objective

We investigated the clinical efficacy of anabolic agents compared with bisphosphonates (BPs) for the incidence of new osteoporotic vertebral fracture (OVF) and fracture healing of OVF in the patients with OVF via meta-analyses of randomized controlled trials (RCTs).

Methods

Electronic databases, including PubMed, Embase, and Cochrane Library were searched for published RCTs till December 2022. The RCTs that recruited participants with osteoporosis at high-/very high-risk of fracture (a history of osteoporotic vertebral or hip fracture) or fresh OVF were included in this study. We assessed the risk of bias on every included RCTs, estimated relative risk (RR) for the incidence of new OVF and fracture healing of OVF, and overall certainty of evidence. Meta-analyses were performed by Cochrane review manager (RevMan) version 5.3. Cochrane risk of bias 2.0 and GRADEpro/GDT were applied for evaluating methodological quality and overall certainty of evidence, respectively.

Results

Five hundred eighteen studies were screened, and finally 6 eligible RCTs were included in the analysis. In the patients with prevalent OVF, anabolic agents significantly reduced the incidence of new OVF (teriparatide and romosozumab vs alendronate and risedronate [RR = 0.57, 95% CI 0.45 - 0.71; p < 0.00001; high-certainty of evidence]; teriparatide vs risedronate [RR = 0.50, 95% CI 0.37 - 0.68; p < 0.0001; high-certainty of evidence]. However, there was no evidence of teriparatide compared to alendronate in fracture healing of OVF (RR = 1.23, 95% CI 0.95 - 1.60; p = 0.12; low-certainty of evidence).

Conclusion

In the patients with prevalent OVF, anabolic agents showed a significant superiority for preventing new OVF than BPs, with no significant evidence for promoting fracture healing of OVF. However, considering small number of RCTs in this study, additional studies with large-scale data are required to obtain more robust evidences.

Differential effects of sevoflurane and desflurane on frontal intraoperative electroencephalogram dynamics associated with postoperative delirium

STUDY OBJECTIVE

Intraoperative electroencephalogram (EEG) patterns associated with postoperative delirium (POD) development have been studied, but the differences in EEG recordings between sevoflurane- and desflurane-induced anesthesia have not been clarified. We aimed to distinguish the EEG characteristics of sevoflurane and desflurane in relation to POD development.

DESIGN AND PATIENTS

We collected frontal four-channel EEG data during the maintenance of anesthesia from 148 elderly patients who received sevoflurane (n = 77) or desflurane (n = 71); 30 patients were diagnosed with delirium postoperatively. The patients were divided into four subgroups based on anesthetics and delirium status: sevoflurane delirium (n = 17), sevoflurane non-delirium (n = 60), desflurane delirium (n = 13), and desflurane non-delirium (n = 58). We compared spectral power, coherence, and pairwise phase consistency (PPC) between sevoflurane and desflurane, and between non-delirium and delirium groups for each anesthetic.

MAIN RESULTS

In patients without POD, the sevoflurane non-delirium group exhibited higher EEG spectral power across 8.5-35 Hz (99.5% CI bootstrap analysis) and higher PPC from alpha to gamma bands (p < 0.005) compared to the desflurane non-delirium group. Conversely, in patients with POD, no significant EEG differences were observed between the sevoflurane and desflurane delirium groups. For the sevoflurane-induced patients, the sevoflurane delirium group had significantly lower power within 7.5-31.5 Hz (99.5% CI bootstrap analysis), reduced coherence over 8.9-23.8 Hz (99.5% CI bootstrap analysis), and lower PPC values in the alpha band (p < 0.005) compared with the sevoflurane non-delirium group. For the desflurane-induced patients, there were no significant differences in the EEG patterns between delirium and non-delirium groups.

CONCLUSIONS

In normal patients without POD, sevoflurane demonstrates a higher power spectrum and prefrontal connectivity than desflurane. Furthermore, reduced frontal alpha power, coherence, and connectivity of intraoperative EEG could be associated with an increased risk of POD. These intraoperative EEG characteristics associated with POD are more noticeable in sevoflurane-induced anesthesia than in desflurane-induced anesthesia.

Optimization of the optical transparency of bones by PACT-based passive tissue clearing

Recent developments in tissue clearing methods such as the passive clearing technique (PACT) have allowed three-dimensional analysis of biological structures in whole, intact tissues, thereby providing a greater understanding of spatial relationships and biological circuits. Nonetheless, the issues that remain in maintaining structural integrity and preventing tissue expansion/shrinkage with rapid clearing still inhibit the wide application of these techniques in hard bone tissues, such as femurs and tibias. Here, we present an optimized PACT-based bone-clearing method, Bone-mPACT+, that protects biological structures. Bone-mPACT+ and four different decalcifying procedures were tested for their ability to improve bone tissue clearing efficiency without sacrificing optical transparency; they rendered nearly all types of bone tissues transparent. Both mouse and rat bones were nearly transparent after the clearing process. We also present a further modification, the Bone-mPACT+ Advance protocol, which is specifically optimized for processing the largest and hardest rat bones for easy clearing and imaging using established tissue clearing methods.

Three-Dimensional Quantitative Assessment of Pedicle Screw Accuracy in Clinical Utilization of a New Robotic System in Spine Surgery: A Multicenter Study

OBJECTIVE

The objective of this study was to evaluate the accuracy of pedicle screw placement in patients undergoing percutaneous pedicle screw fixation with robotic guidance, using a newly developed 3-dimensional quantitative measurement system. The study also aimed to assess the clinical feasibility of the robotic system in the field of spinal surgery.

METHODS

A total of 113 patients underwent pedicle screw insertion using the CUVIS-spine pedicle screw guide system (CUREXO Inc.). Intraoperative O-arm images were obtained, and screw insertion pathways were planned accordingly. Image registration was performed using paired-point registration and iterative closest point methods. The accuracy of the robotic-guided pedicle screw insertion was assessed using 3-dimensional offset calculation and the Gertzbein-Robbins system (GRS).

RESULTS

A total of 448 screws were inserted in the 113 patients. The image registration success rate was 95.16%. The average error of entry offset was 2.86 mm, target offset was 2.48 mm, depth offset was 1.99 mm, and angular offset was 3.07°. According to the GRS grading system, 88.39% of the screws were classified as grade A, 9.60% as grade B, 1.56% as grade C, 0.22% as grade D, and 0.22% as grade E. Clinically acceptable screws (GRS grade A or B) accounted for 97.54% of the total, with no reported neurologic complications.

CONCLUSION

Our study demonstrated that pedicle screw insertion using the novel robot-assisted navigation method is both accurate and safe. Further prospective studies are necessary to explore the potential benefits of this robot-assisted technique in comparison to conventional approaches.

Predicting Mechanical Complications After Adult Spinal Deformity Operation Using a Machine Learning Based on Modified Global Alignment and Proportion Scoring With Body Mass Index and Bone Mineral Density

Objective: This study aimed to create an ideal machine learning model to predict mechanical complications in adult spinal deformity (ASD) surgery based on GAPB (modified global alignment and proportion scoring with body mass index and bone mineral density) factors.Methods: Between January 2009 and December 2018, 238 consecutive patients with ASD, who received at least 4-level fusions and were followed-up for ≥ 2 years, were included in the study. The data were stratified into training (n = 167, 70%) and test (n = 71, 30%) sets and input to machine learning algorithms, including logistic regression, random forest gradient boosting system, and deep neural network.Results: Body mass index, bone mineral density, the relative pelvic version score, the relative lumbar lordosis score, and the relative sagittal alignment score of the global alignment and proportion score were significantly different in the training and test sets (p < 0.05) between the complication and no complication groups. In the training set, the area under receiver operating characteristics (AUROCs) for logistic regression, gradient boosting, random forest, and deep neural network were 0.871 (0.817–0.925), 0.942 (0.911–0.974), 1.000 (1.000–1.000), and 0.947 (0.915–0.980), respectively, and the accuracies were 0.784 (0.722–0.847), 0.868 (0.817–0.920), 1.000 (1.000–1.000), and 0.856 (0.803–0.909), respectively. In the test set, the AUROCs were 0.785 (0.678–0.893), 0.808 (0.702–0.914), 0.810 (0.710–0.910), and 0.730 (0.610–0.850), respectively, and the accuracies were 0.732 (0.629–0.835), 0.718 (0.614–0.823), 0.732 (0.629–0.835), and 0.620 (0.507–0.733), respectively. The random forest achieved the best predictive performance on the training and test dataset.Conclusion: This study created a comprehensive model to predict mechanical complications after ASD surgery. The best prediction accuracy was 73.2% for predicting mechanical complications after ASD surgery.

Comparison of Whole Spine Sagittal Alignment in Patients with Spinal Disease between EOS Imaging System versus Conventional Whole Spine X-ray

PURPOSE

The biplanar whole body imaging system (EOS) is a new tool for measuring the whole body sagittal alignment in a limited space. This tool may affect the sagittal balance of patients compared to conventional whole spine X-ray (WSX). This study aimed to investigate the difference in sagittal alignment between WSX and EOS.

MATERIALS AND METHODS

We compared the spinal and pelvic sagittal parameters in 80 patients who underwent EOS and WSX within one month between July 2018 and September 2019. The patients were divided based on sagittally balanced and imbalanced groups according to pelvic tilt (PT) >20°, pelvic incidence-lumbar lordosis >10°, C7-sagittal vertical axis (SVA) >50 mm in WSX.

RESULTS

In the sagittally imbalanced group, compared to WSX, the pelvic parameters demonstrated compensation in EOS with smaller PT (27.4±11.6° vs. 24.9±10.9°, p=0.003) and greater sacral slope (SS), and the patients tended to stand more upright with smaller C7-SVA (58.4±17.0 mm vs. 48.9±57.3 mm, p=0.018), T1-pelvic angle (TPA), T5-T12, and T2-T12. However, in the sagittally balanced group, these differences were less pronounced only with smaller PT (10.8±6.9° vs. 9.4±4.7°, p=0.040), TPA and T2-T12 angle, but with similar SS and C7-SVA (p>0.05).

CONCLUSION

EOS showed a negative SVA shift and lesser PT compared to WSX, especially in patients with sagittal imbalance. When preparing a surgical plan, surgeons should consider these differences between EOS and WSX.

Modified Global Alignment and Proportion Scoring With Body Mass Index and Bone Mineral Density Analysis in Global Alignment and Proportion Score of Each 3 Categories for Predicting Mechanical Complications After Adult Spinal Deformity Surgery

OBJECTIVE

This study aimed to analyze the prediction rate of the modified Global Alignment and Proportion (GAP) scoring system with body mass index and bone mineral density (GAPB) in each GAP of the 3 categories.

METHODS

Between January 2009 and December 2016, 203 consecutive patients with adult spinal deformity (ASD) underwent corrective fusion of more than 4 levels and were followedup for more than 2 years. As a validation of the GAPB, the GAPB was divided into tertiles (Q1, Q2, Q3) for each section of the GAP score. Each patient's GAP score and GAPB system complication rate were examined.

RESULTS

Of the 203 patients, 89 patients (44%) developed mechanical complications after ASD surgery. A GAP score analysis of the patients found that 42 patients were proportioned, 85 patients were moderately disproportioned, and 76 patients were severely disproportioned. Mechanical complications occurred with increasing GAPB in the proportioned group, but were not statistically significant (p = 0.0534). However, mechanical complications occurred in a statistically significant manner in the moderately disproportioned and severely disproportioned groups as GAPB increased (p < 0.001).

CONCLUSION

The GAPB system showed improved predictability for mechanical complications after surgery for ASD in each category of the GAP score.

Characteristics and Risk Factors of Rod Fracture Following Adult Spinal Deformity Surgery: A Systematic Review and Meta-Analysis

Objective

The aim of study is to investigate the features and risk factors of rod fracture (RF) following adult spinal deformity (ASD) surgery.

Methods

We searched the PubMed, Embase, Web of Science, and Cochrane Library databases to identify relevant studies. Patient’s data including age, sex, body mass index (BMI), previous spine surgery, pedicle subtraction osteotomy (PSO), interbody fusion, fusion to the pelvis, smoking history, preoperative sagittal vertical axis (SVA), preoperative pelvic tilt (PT), preoperative pelvic incidence minus lumbar lordosis, preoperative thoracic kyphosis (TK), and change in the SVA were documented. Comparable factors were evaluated using odds ratio (OR) and weighted mean difference (WMD) with 95% confidence interval (CI).

Results

Seven studies were included. The overall incidence of RF following ASD surgery was 12%. Advanced age (WMD, 2.8; 95% CI, 1.01–4.59; p<0.002), higher BMI (WMD, 1.98; 95% CI, 0.65–3.31; p=0.004), previous spine surgery (OR, 1.47; 95% CI, 1.05–2.04; p=0.02), PSO (OR, 2.28; 95% CI, 1.62–3.19; p<0.0001), a larger preoperative PT (WMD, 6.17; 95% CI, 3.55–8.97; p<0.00001), and a larger preoperative TK (WMD, 5.19; 95% CI, 1.41–8.98; p=0.007) were identified as risk factors for incidence of RF.

Conclusion

The incidence of RF in patients following ASD surgery was 12%. Advanced age, higher BMI, previous spine surgery, and PSO were significantly associated with an increased occurrence of RF. A larger preoperative PT and TK were also identified as risk factors for occurrence of RF following ASD surgery.

Comparison of Zero-profile Anchored Spacer Versus Plate-and-Cage After 1-Level ACDF With Complete Uncinate Process Resection: A 3-Year Assessment of Radiographic and Clinical Outcomes

STUDY DESIGN

This is a retrospective study.

OBJECTIVE

The purpose of this study is to compare the zero-profile anchored spacer device (Zero-p) and traditional plate-and-cage implant (plate-and-cage) in anterior cervical discectomy and fusion (ACDF) with complete uncinate process resection (UPR) to treat 1-level cervical degenerative disk disease.

SUMMARY OF BACKGROUND DATA

We retrospectively surveyed the data from all patients who underwent single-level ACDF with complete UPR between 2009 and 2013.

PATIENTS AND METHODS

In total, 80 patients participated in 3 years of follow-up. Among them, Zero-p (38 patients) and plate-and-cage (42 patients) approaches were used in ACDF with complete UPR. Clinical outcomes and radiographic results were compared between 2 groups and they were followed for 39.1±2.2 months.

RESULTS

Duration of operation, intraoperative blood loss, and length of hospitalization were significantly lower in the Zero-p group than the plate-and-cage group (P<0.001). The clinical outcomes of visual analog scale, neck disability index, and the Odom criteria were improved after operation in both groups. The fusion rates, C2-C7 lordosis, T1 slope, C2-C7 sagittal vertical axis, sellar turcica-C7 sagittal vertical axis, and spinocranial angle after single-level ACDF were not significantly different between the 2 groups. Subsidence occurred in 5 cases (13%) in the Zero-p group and 10 cases (37%) in the plate-and-cage group (P<0.05). The horizontal length of the Zero-p implant was longer than that of allograft bone. Fusion occurred in 37 cases (95%) of the Zero-p group and 40 cases (94%) in the plate-and-cage group.

CONCLUSIONS

The Zero-p and plate-and-cage are effective when single-level ACDF with complete UPR was performed. Both groups showed good clinical outcomes, but Zero-p has more benefits than plate-and-cage such as lower duration of operation, intraoperative blood loss, length of hospitalization, and rate of subsidence compared with plate-and-cage. Surgeons should be aware of these results so that postoperative complications such as subsidence can be avoided.

The Fate of Proximal Junctional Vertebral Fractures after Long-Segment Spinal Fixation : Are There Predictable Radiologic Characteristics for Revision surgery?

OBJECTIVE

To investigate the radiographic characteristics of the uppermost instrumented vertebrae (UIV) and UIV+1 compression fractures that are predictive of revision surgery following long-segment spinal fixation.

METHODS

A total 27 patients who presented newly developed compression fracture at UIV, UIV+1 after long segment spinal fixation (minimum 5 vertebral bodies, lowest instrumented vertebra of L5 or distal) were reviewed retrospectively. Patients were divided into two groups according to following management : revisional surgery (group A, n=13) and conservative care (group B, n=14). Pre- and postoperative images, and images taken shortly before and after the occurrence of fracture were evaluated for radiologic characteristics.

RESULTS

Despite similar degrees of surgical correction of deformity, the fate of the two groups with proximal junctional compression fractures differed. Immediately after the fracture, the decrement of adjacent disc height in group A (32.3±7.6 mm to 23.7±8.4 mm, Δ=8.5±6.9 mm) was greater than group B (31.0±13.9 mm to 30.1±15.5 mm, Δ=0.9±2.9 mm, p=0.003). Pre-operative magnetic resonance imaging indicated that group A patients have a higher grade of disc degeneration adjacent to fractured vertebrae compared to group B (modified Pfirrmann grade, group A : 6.10±0.99, group B : 4.08±0.90, p=0.004). Binary logistic regression analysis indicated that decrement of disc height was the only associated risk factor for future revision surgery (odds ratio, 1.891; 95% confidence interval, 1.121-3.190; p=0.017).

CONCLUSION

Proximal junctional vertebral compression fractures with greater early-stage decrement of adjacent disc height were associated with increased risk of future neurological deterioration and necessity of revision. The condition of adjacent disc degeneration should be considered regarding severity and revision rate of proximal junctional kyphosis/proximal junction failures.

Revision Surgery for a Failed Artificial Disc

PURPOSE

This study aimed to present our experience with failures in C-TDR and revision surgery outcomes.

MATERIALS AND METHODS

We retrospectively examined patients who underwent revision surgery due to the failure of C-TDR between May 2005 to March 2019. Thirteen patients (8 males and 5 females) were included in this study. The mean age was 46.1 years (range: 22-61 years), and the average follow-up period was 19.5 months (range: 12-64 months). The outcome measures of pre- and post-operative neck and arm pain using a visual analogue scale (VAS) and functional impairment were assessed using a modified Japanese Orthopedic Association (JOA) scale and the Neck Disability Index (NDI).

RESULTS

The main complaints of patients were posterior neck pain (77%), radiculopathy (62%), and/or myelopathy (62%). The causes of failure of C-TDR were improper indications for the procedure, osteolysis and mobile implant use, inappropriate techniques, and postoperative infection. The most common surgical level was C5-6, followed by C4-5. After revision surgery, the neck and arm pain VAS (preoperative vs. postoperative: 5.46 vs. 1.31; 4.86 vs. 1.08), a modified JOA scale (14.46 vs. 16.69), and the NDI (29.77 vs. 9.31) scores were much improved.

CONCLUSION

C-TDR is good surgical option. However, it is very important to adhere to strict surgical indications and contraindications to avoid failure of C-TDR. The results of reoperations were good regardless of the approach. Therefore, various reoperation options could be considered in patients with failed C-TDR.

Surgical Strategy for Sacral Tumor Resection

PURPOSE

This study aimed to present our experiences with a precise surgical strategy for sacrectomy.

MATERIALS AND METHODS

This study comprised a retrospective review of 16 patients (6 males and 10 females) who underwent sacrectomy from 2011 to 2019. The average age was 42.4 years old, and the mean follow-up period was 40.8 months. Clinical data, including age, sex, history, pathology, radiographs, surgical approaches, onset of recurrence, and prognosis, were analyzed.

RESULTS

The main preoperative symptom was non-specific local pain. Nine patients (56%) complained of bladder and bowel symptoms. All patients required spinopelvic reconstruction after sacrectomy. Three patients, one high, one middle, and one hemi-sacrectomy, underwent spinopelvic reconstruction. The pathology findings of tumors varied (chordoma, n=7; nerve sheath tumor, n=4; giant cell tumor, n=3, etc.). Adjuvant radiotherapy was performed for 5 patients, chemotherapy for three, and combined chemoradiotherapy for another three. Six patients (38%) reported postoperative motor weakness, and newly postoperative bladder and bowel symptoms occurred in 5 patients. Three patients (12%) experienced recurrence and expired.

CONCLUSION

In surgical resection of sacral tumors, the surgical approach depends on the size, location, extension, and pathology of the tumors. The recommended treatment option for sacral tumors is to remove as much of the tumor as possible. The level of root sacrifice is a predicting factor for postoperative neurologic functional impairment and the potential for morbidity. Pre-operative angiography and embolization are recommended to prevent excessive bleeding during surgery. Spinopelvic reconstruction must be considered following a total or high sacrectomy or sacroiliac joint removal.

Anterior cervical discectomy and fusion vs posterior laminoplasty for the treatment of myelopathy due to two-level localized ossification of the posterior longitudinal ligament

We conducted a retrospective study to compare the clinical and radiological results of anterior cervical discectomy and fusion (ACDF) and posterior laminoplasty for two-level localized ossification of the posterior longitudinal ligament (OPLL).ACDF and posterior laminoplasty are performed for localized OPLL at the disc and vertebral body levels, respectively.Eighty six patients with two-level localized OPLL who underwent surgery from January 2011 to December 2016 were retrospectively investigated (41, ACDF group; 45, laminoplasty group). Clinical outcomes were reviewed, and radiologic results such as occupying ratio (OR), space available in the spinal cord, cranial and caudal OPLL-to-disc distance (ODD)/posterior body height (PBH) ratios, segmental angle, C2-C7 Cobb angle, T1 slope, C2-C7 sagittal vertical axis (SVA), and range of motion were investigated.Patients were followed-up for an average of 42.7 ± 10.5 months. Clinical outcomes, postoperative OR, and space available in the spinal cord were significantly improved at the final follow-up in both groups. Preoperatively, the OR and cranial and caudal ODD/PBH ratios were not significantly different between the groups. Compared to pre-operative values, differences in the segmental and C2-C7 Cobb angles at the final follow-up were statistically significant for the ACDF group (P < .05). The mean operative time, bleeding volume, and the duration of hospitalization were significantly lower in the ACDF group than in the laminoplasty group (P < .05). Complications occurred in 1 ACDF case and in 5 laminoplasty cases.Both ACDF and laminoplasty provided satisfactory clinical and radiologic outcomes for two-level localized OPLL. However, ACDF was associated with a lower operation time, bleeding loss, duration of hospitalization, and complications.

Association of complete uncinate process removal on 2-year assessment of radiologic outcomes: subsidence and sagittal balance in patients receiving one-level anterior cervical discectomy and fusion

Background

Many patients with cervical radiculopathy experience stenosis of the neural foramens due to cumulative osteophyte or uncovertebral joint hypertrophy. For cervical foraminal stenosis, complete uncinate process resection (UPR) is often conducted concurrently with anterior discectomy and fusion (ACDF). The aim of this study was to assess the clinical and radiological outcomes of ACDF with complete UPR versus ACDF without UPR.

Methods

In total, 105 patients who performed one-level ACDF with a cage-and-plate construct between 2011 and 2015 were retrospectively reviewed. Among them, 37 patients had ACDF with complete UPR, and 68 patients had ACDF without UPR. Radiologic outcomes of disc height, C2–C7 lordosis, T1 slope, C2–C7 sagittal vertical axis (SVA), center of the sella turcica–C7 SVA (St-SVA), spino-cranial angle (SCA), and fusion rate were evaluated on plain X-ray at pre-operation, immediately post-operation, and at 2-year follow-up. For statistically matched pairs analysis, ACDF with UPR group (24 patients) and ACDF without UPR (24 patients) were compared.

Results

All of the clinical parameters improved at the 2-year follow up (P < 0.0001). Improvement in visual analogue scale (VAS) scores for arm pain was significantly improved in the ACDF with complete UPR group immediately post-operation. All cervical sagittal parameters, including cervical lordosis, segmental angle, disc height, C2-C7 SVA, St-SVA, T1 slope, and SCA, except for preoperative St-SVA, SCA, and disc height of 2 years follow-up, were similar between the ACDF with complete UPR and ACDF without UPR groups. Differences in disc height, C2-C7 SVA, and SCA at 2-year follow up after preoperative examination, however, were statistically significant (p < 0.05). Subsidence occurred in 9 patients (ACDF with complete UPR: 8 cases [33%] versus ACDF without UPR: 1 cases [4%]; p < 0.05).

Conclusions

Cervical sagittal alignment after ACDF with complete UPR is not significantly different from that achieved with ACDF without UPR. However, subsidence appears to occur more often after ACDF with complete UPR than after ACDF without UPR, although with little to no clinical impact. More precise and careful selection of patients is needed when deciding on additional complete UPR.

Modified global alignment and proportion scoring with body mass index and bone mineral density (GAPB) for improving predictions of mechanical complications after adult spinal deformity surgery

BACKGROUND CONTEXT

The global alignment and proportion (GAP) score for predicting mechanical complications of adult spinal deformity (ASD) surgery has limitations due to its lack of bone quality and patient characteristics such as obesity, which has a significant impact on surgical outcome, especially in the elderly population with ASD.

PURPOSE

This study aimed to improve the predictability of GAP score after ASD surgery by adding body mass index (BMI) and bone mineral density (BMD).

DESIGN

A retrospective comparative study.

PATIENT SAMPLE

Between January 2009 and December 2016, 203 consecutive patients with ASD underwent corrective fusion of more than 4 levels and were followed up for more than 2 years.

OUTCOME MEASURES

The ability of the Scoliosis Research Society (SRS)-Schwab classification, age-adjusted alignment goals, GAP score, and modified global alignment and proportion scoring with BMI and BMD (GAPB) to predict mechanical failure was compared by calculating the area under the receiver operating characteristic curve (AUC).

METHODS

The GAPB was developed and validated in patients randomly assigned to derivation (n=125, 61.6%) and validation (n=78, 38.4%) cohorts. Considering multicollinearity, a multivariable logistic regression model with BMD, BMI, and the GAP score was constructed.

RESULTS

Patients' average age was 66.8±12.28 years, and they were followed for an average of 30.54±10.25 months. Fifty-five patients of the derivation cohort (44%) and 34 patients of the validation cohort (43%) had mechanical complications after ASD surgery. AUCs of the SRS-Schwab classification, GAP score, age-adjusted alignment goals, and GAPB were 0.532 (95% confidence interval [CI], 0.463-0.602), 0.798 (95% CI, 0.720-0.877), 0.568 (95% CI, 0.495-0.641), and 0.885 (95% CI 0.828-0.941), respectively.

CONCLUSIONS

The GAPB system, which includes BMI and BMD, showed improved predictability for predicting mechanical complications compared to the GAP score. Given these results, surgeons should keep in mind the importance of bone quality and BMI as well as proportional alignment.

Preoperative radiographic clues for transdural disc herniation: could it be predictable?

BACKGROUND

Transdural disc herniation (TDH) is a rare event accounting for 0.3-1.5% of all disc herniation cases. Considering the risk of leakage of the cerebrospinal fluid from the dural defect after removal of TDH or incomplete removal, it is very important to recognize TDH before surgery. This study is a retrospective case analysis to analyze the imaging findings of seven cases and to construct a preoperative prediction model for TDH.

METHODS

Retrospective radiographic examination was performed among patients operated for TDH in two institutions from 2008 to 2018. The radiographic images were analyzed according to the following eight signs: including absence of dural tent, complete block of spinal canal, hawk-beak sign, double-layered lesion, increased distance between the dura and cauda equina, rim enhancement, dural tent enhancement, and epidural gas. To clarify the predictive ability of these radiographic signs, consecutive 131 surgically confirmed epidural disc herniation (EDH) patients for the last 2 years were set as a control group for TDH. The sum of radiographic findings was compared between TDH and EDH patients to determine the cutoff value.

RESULTS

There were 1 thoracic and 6 lumbar TDHs among 75 thoracic and 6674 lumbar disc herniation cases with an incidence of 1.33% and 0.09%, respectively. Dural tent (p = 0.000, odds ratio = 106.67), double-layered lesion (p = 0.000, odds ratio = 22.69), and distance between the dura and cauda equina (p = 0.007, odds ratio = 52.00) were statistically significantly different between TDH and EDH. According to the receiver operating characteristic curve, the cutoff value of 1.5 had 85.7% sensitivity and 90.8% specificity.

CONCLUSION

Preoperative imaging can be useful for TDH diagnosis. It is safe to consider the possibility of TDH in patients with more than two findings in the preoperative images.

Comparison of Endovascular Embolization and Surgery in the Treatment of Spinal Intradural Dorsal Arteriovenous Fistulas

BACKGROUND

We compared the outcomes of endovascular embolization and surgery and investigated the factors affecting the clinical outcomes of spinal intradural dorsal arteriovenous fistulas (SIDAVFs).

METHODS

The medical records of 26 patients who had undergone endovascular embolization or surgery for SIDAVFs from 2004 to 2014 were retrospectively reviewed. The recurrence rate and clinical outcomes for each treatment modality were compared. Multivariate analysis was used to identify significant factors influencing the clinical outcomes using the Aminoff and Logue (AL) score.

RESULTS

Of the 26 patients, 14 (56%) had undergone endovascular embolization and 11 (44%) had undergone surgery as the initial treatment. Embolization was applied as the primary treatment for most patients. Surgery was chosen for patients with difficult superselection (n = 5), multiple feeders (n = 2), or easy surgical accessibility (n = 4). Of the 14 patients who had undergone embolization as initial treatment, 5 (36%) had developed a recurrence within an average of 29.6 months (range, 2-87). One patient with recurrent SIDAVF was treated with repeat embolization and four with surgery. None of patients in the surgical group developed recurrence. Embolization as the initial treatment resulted in significantly greater recurrence compared with surgery (odds ratio, 2.222; 95% confidence interval, 1.369-3.608; P = 0.046). Surgery resulted in better clinical outcomes than embolization (P = 0.021). The final AL score was also strongly affected by the preoperative AL score, micturition score, and recurrence (P = 0.000, P = 0.000, and P = 0.011, respectively).

CONCLUSIONS

Our results have shown that surgery results in a low recurrence rate and superior clinical outcomes. A multidisciplinary and ordered decision is crucial for the treatment choice to ensure better outcomes, especially for patients with a definite neurologic deficit at diagnosis.

Late-Developing Metastatic Malignant Melanoma in the Thoracic Spine Originating from Choroidal Melanoma

A 54-year-old woman visited Gangnam Severance Hospital for left side flank pain. She had a history of total removal of malignant melanoma on the left eye ball 20 years prior. No evaluation had been performed since then. A paravertebral mass at thoracic ninth level (T9) was discovered on spinal magnetic resonance imaging, and pathology confirmed malignant melanoma. Following positron emission tomography-computed tomography, no other metastasis was discovered. After removal of the paravertebral mass, palliative chemotherapy (dacabarzine + tamoxifene) was administered in 3 cycles over 2 months. Radiotherapy with simultaneous integrated boost technique was performed at 4,350 cGy total over 15 days, 290 cGy per delivery, and was administered with the first cycle of palliative chemotherapy. Despite this treatment, multiple metastases developed throughout her body 7 months later, and the patient is continuing chemotherapy.

Management of Esophageal and Pharyngeal Perforation as Complications of Anterior Cervical Spine Surgery

OBJECTIVE

To describe our experience in treating esophageal and pharyngeal perforation after anterior cervical spine surgery.

METHODS

Six patients with esophageal injury and one patient with pharyngeal injury after anterior cervical spinal surgery, managed at our department between 2000 and 2015, were analyzed retrospectively.

RESULTS

During the study period, 7 patients (6 male and 1 female; mean age, 45 years) presented with esophageal perforation. The original anterior cervical spinal surgery was performed due to trauma in 2 patients and because of a degenerative cervical disorder in 5. Early esophageal perforation was diagnosed in 2 patients, and delayed esophageal injury due to chronic irritation with the cervical implants was noted in 5. Three of the five delayed perforation cases were related to cervical instrument displacement. Two patients showed no definite signs of infection, whereas 5 patients had various symptoms, including fever, neck pain, odynophagia, neck swelling, and upper extremity weakness. Two patients with a large defect underwent surgical repair and three with minimal perforation due to chronic irritation from the implants underwent instrument removal without direct repair of defect. Two asymptomatic patients received no intervention. Six patients with infection completely recovered from esophageal injury after treatment for a mean duration of 5.2 weeks (range, 4-8 weeks). One patient died because of postoperative pneumonia and sepsis after implant removal.

CONCLUSIONS

Esophageal and pharyngeal injury after cervical spinal surgery may occur either directly due to spinal trauma and vigorous intraoperative retraction or due to chronic irritation with cervical implants. In cases of perforation associated with infection, various surgical modalities, including primary closure and reinforcement with a flap, could be considered depending on factors such as esophageal defect size, infection severity, and timing of recognition of injury.

The Influences of Different Ratios of Biphasic Calcium Phosphate and Collagen Augmentation on Posterior Lumbar Spinal Fusion in Rat Model

PURPOSE

To determine the influence of different ratios of hydroxyapatite (HA)/beta tricalcium phosphate (β-TCP) and collagen augmentation for posterior lumbar fusion in a rat model.

MATERIALS AND METHODS

We generated a posterior lumbar fusion model in 50 rats and divided it into five groups of equal number as follows; 1) autologous bone graft as group A, 2) 70% HA+30% β-TCP as group B, 3) 70% HA+30% β-TCP+collagen as group C, 4) 30% HA+70% β-TCP as group D, and 5) 30% HA+70% β-TCP+collagen as group E. Rats were euthanized at 12 weeks after surgery and fusion was assessed by manual palpation, quantitative analysis using microCT and histology.

RESULTS

The score of manual palpation was significantly higher in group C than group E (3.1±1.1 vs. 1.8±0.8, p=0.033). However, in terms of microCT analysis, group D showed significantly higher scores than group B (5.5±0.8 vs. 3.1±1.1, p=0.021). According to quantitative volumetric analysis, 30% HA+70% β-TCP groups (group D and E) showed significantly reduced fusion mass at 12 weeks after surgery (123±14.2, 117±46.3 vs. 151±27.3, p=0.008, 0.003, respectively). Collagen augmentation groups revealed superior results in terms of both microCT score and histologic grade.

CONCLUSION

A 7:3 HA/β-TCP ratio with collagen augmentation rather than a 3:7 HA/β-TCP ratio could be a more favorable graft substitute for lumbar spinal fusion. There was positive role of collagen as an adjunct for spinal bone fusion process.

Changes in Bone Metabolism in Young Castrated Male Rats

PURPOSE

To determine the window of time during which osteoporosis affects the management of spinal surgery and the mechanism of bone metabolism changes in males with osteoporosis by examining changes in bone metabolism in young castrated male rats.

MATERIALS AND METHODS

A total of 30 Sprague-Dawley rats were randomly allocated into two study groups. Group 1 (control) received a sham surgery and Group 2 received bilateral orchiectomy to change bone mineral density (BMD). Serum osteocalcin, alkaline phosphatase (ALP), and collagen type 1 cross-linked C-telopeptide (CTX) were analyzed at postoperative date (POD) 8, 10, and 12 weeks. BMDs were measured using micro computed tomography scans.

RESULTS

Femoral and lumbar BMDs were decreased in the orchiectomy groups. BMDs in the sham and orchiectomy groups showed statistically differences at POD 8, 10, and 12 weeks for the femur (p=0.032, 0.008, 0.008) and lumbar spine (p=0.151, 0.008, 0.008, respectively). Serum osteocalcin, ALP, and CTX decreased gradually; however, N-terminal type 1 procollagen (P1NP) showed a slight increase yet no significant change.

CONCLUSION

In young castrated male rats, a significant decrease in BMD was observed after orchiectomy due to the mixture of two detrimental factors. Young castrated male rats did not reach peak BMD. Increased bone turnover causes bone resorption to exceed bone formation. This study may contribute to the creation of a valuable model for studies of male osteoporosis and the spinal surgery field.

Paraspinal muscle, facet joint, and disc problems: risk factors for adjacent segment degeneration after lumbar fusion

BACKGROUND CONTEXT

Adjacent segment degeneration (ASD) is one of the major complications after lumbar fusion. Several studies have evaluated the risk factors of ASD. Although the paraspinal muscles play an important role in spine stability, no study has assessed the relationship between paraspinal muscle atrophy and the incidence of ASD after lumbar fusion.

PURPOSE

In the present study, we aimed to verify the known risk factors of ASD, such as body mass index (BMI), preoperative adjacent facet joint degeneration, and disc degeneration, and to assess the relationship between paraspinal muscle atrophy and ASD.

STUDY DESIGN

This is a retrospective 1:1 pair analysis matched by age, sex, fusion level, and follow-up period.

PATIENT SAMPLE

To calculate the appropriate sample size for the study, we performed a pre-study analysis of the paraspinal muscle cross-sectional area (CSA), and estimated that at least 35 cases would be needed for each group. Among the 510 patients who underwent posterior lumbar fusion for degenerative lumbar disease between January 2009 and October 2009, a total of 50 patients with ASD after surgery were selected. Another group of 50 matched patients with degenerative lumbar disease without ASD after spinal fusion were selected as the control group. Each patient in the ASD group was matched with a control patient according to age, sex, fusion level, and follow-up period.

OUTCOME MEASURES

Radiographic measurements and demographic data were reviewed.

METHODS

The risk factors considered were higher BMI, preoperative adjacent segment disc and facet degeneration, and preoperative paraspinal muscle atrophy and fatty degeneration. The radiographic data were compared between the ASD and control groups to determine the predictive factors of ASD after posterior lumbar fusion by using logistic regression analysis. The study was not externally funded. The authors have no conflict of interest to declare.

RESULTS

Multivariate logistic regression analysis indicated that higher BMI (odds ratio [OR]: 1.353, p=.008), preoperative facet degeneration on computed tomography examination (OR: 3.075, p=.011), disc degeneration on magnetic resonance imaging (MRI) (OR: 2.783, p=.003), fatty degeneration (OR: 1.080, p=.044), and a smaller relative CSA of the paraspinal muscle preoperatively (OR: 0.083, p=.003) were significant factors for predicting the development of ASD.

CONCLUSIONS

The occurrence of radiological ASD is most likely multifactorial, and is associated with a higher BMI, preexisting facet and disc degeneration on preoperative examination, and a smaller preoperative relative CSA of the paraspinal muscle on MRI.

Minimally Invasive Transforaminal Lumbar Interbody Fusion in Multilevel: Comparison with Conventional Transforaminal Interbody Fusion

OBJECTIVE

Minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) has shown superior or noninferior results compared with conventional TLIF in single segments. There were no comparative studies between MIS and conventional TLIF in multisegments. The purpose of this study was to compare MIS and conventional TLIF in multisegments.

METHODS

This is a cross-sectional study of 2- or 3-segment lumbar degenerative disease that was treated with either MIS (27 cases) or conventional TLIF (43 cases). Whole spine sagittal radiography was done preoperatively and 1 year after surgery. Clinical outcomes, perioperative outcomes, and fusion rate were compared. Radiologic parameters, such as cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and pelvic parameters, were measured 1 year after surger.

RESULTS

The two groups were similar in age, sex, preoperative diagnosis, operated level, and follow-up period. Both groups showed improvement in visual analog scale and Oswestry disability index after surgery. The MIS TILF group had a significantly shorter operation time (167.10 vs. 216.58 minutes) and less blood loss (532.41 vs. 865.81 mL). Only cervical lordosis (MIS TLIF, -17.2°; conventional TLIF, -11.2°) was significantly different preoperatively between the groups. Postoperatively, there were no significant differences in radiologic parameter and fusion rate. In the intragroup comparisons, thoracic kyphosis, lumbar lordosis, and sacral slope were significantly increased and pelvic tilt was significantly decreased after surgery.

CONCLUSIONS

MIS TLIF and conventional TLIF showed similar clinical and radiologic outcomes. MIS TLIF may be a better choice for 2- or 3-segment lumbar fusion in perioperative outcomes.

Prevalence, Distribution, and Significance of Incidental Thoracic Ossification of the Ligamentum Flavum in Korean Patients with Back or Leg Pain : MR-Based Cross Sectional Study

OBJECTIVE

Thoracic ossification of the ligamentum flavum (OLF) is a relatively rare disease. Because of ambiguous clinical symptom, it is difficult for early diagnosis of OLF and subsequent treatment can be delayed or missed. Therefore, the purpose of this study is to comprehensively assess the prevalence and distribution of thoracic OLF by magnetic resonance imaging (MRI) and coexisting spinal disease in Korean patients with back pain or leg pain.

METHODS

The sample included 2134 Korean patients who underwent MRI evaluation for back pain. The prevalence and distribution of thoracic OLF were assessed using lumbar MRI with whole spine sagittal images. Additionally, we examined the presence of coexisting lumbar and cervical diseases. The presence of thoracic OLF as well as clinical parameters such as age, sex, and surgery were retrospectively reviewed.

RESULTS

The prevalence of thoracic OLF in total patients was 16.9% (360/2134). The prevalence tended to increase with aging and was higher in women than in men. The lower thoracic segment of T10-11 was the most frequently affected segment. Of the 360 patients with OLF, 31.9% had coexisting herniated thoracic discs at the same level. Approximately 74% of the patients with OLF had coexisting lumbar and cervical disease. Nine (2.5%) of 360 OLF patients underwent surgery for thoracic lesion.

CONCLUSION

The prevalenceof thoracic OLF was relatively higher than those of previous reports. And coexisting lumbar and cervical disease were very frequent. Therefore, we should check coexisting spinal diseases and the exact diagnostic localization of ossification besides lumbar disease.

Bone Mineral Density Changes after Orchiectomy using a Scrotal Approach in Rats

Objective

To investigate a suitable animal model for studies of male osteoporosis. Osteoporosis has a particularly high incidence in postmenopausal women, resulting in a substantial amount of research with respect to this disease in women. However, research on osteoporosis in men is still lacking.

Methods

Twenty 10-week-old male Sprague Dawley rats were used in this study, including 4 rats used to establish a baseline bone mineral density (BMD). The other 16 rats were divided into two groups: a sham surgery group (n=8), which underwent a sham operation, and an orchiectomized rat group (OCX) (n=8), which underwent bilateral OCX at 10 weeks of age. Bone mineral density was measured in 4 rats from both the sham surgery group and the OCX group 8 weeks after the surgery, while BMD in the remainder of the rats was measured 10 weeks post-surgery.

Results

Femoral BMD at 8 weeks post-surgery was found to be significantly lower in the OCX group compared to the sham group; a finding that was also similar 10 weeks post-surgery.

Conclusion

8 weeks after undergoing orchiectomy performed via a scrotal, white rats are a suitable model for studies of male osteoporosis.

Anterior Cervical Discectomy and Fusion Alters Whole-Spine Sagittal Alignment

PURPOSE

Anterior cervical discectomy and fusion (ACDF) has become a common spine procedure, however, there have been no previous studies on whole spine alignment changes after cervical fusion. Our purpose in this study was to determine whole spine sagittal alignment and pelvic alignment changes after ACDF.

MATERIALS AND METHODS

Forty-eight patients who had undergone ACDF from January 2011 to December 2012 were enrolled in this study. Cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis (SVA), and pelvic parameters were measured preoperatively and at 1, 3, 6, and 12 months postoperatively. Clinical outcomes were assessed using Visual Analog Scale (VAS) scores and Neck Disability Index (NDI) values.

RESULTS

Forty-eight patients were grouped according to operative method (cage only, cage & plate), operative level (upper level: C3/4 & C4/5; lower level: C5/6 & C6/7), and cervical lordosis (high lordosis, low lordosis). All patients experienced significant improvements in VAS scores and NDI values after surgery. Among the radiologic parameters, pelvic tilt increased and sacral slope decreased at 12 months postoperatively. Only the high cervical lordosis group showed significantly-decreased cervical lordosis and a shortened SVA postoperatively. Correlation tests revealed that cervical lordosis was significantly correlated with SVA and that SVA was significantly correlated with pelvic tilt and sacral slope.

CONCLUSION

ACDF affects whole spine sagittal alignment, especially in patients with high cervical lordosis. In these patients, alteration of cervical lordosis to a normal angle shortened the SVA and resulted in reciprocal changes in pelvic tilt and sacral slope.

Minimally Invasive Transforaminal Lumbar Interbody Fusion for Spondylolisthesis: Comparison Between Isthmic and Degenerative Spondylolisthesis

INTRODUCTION

Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is a common surgical option for degenerative spondylolisthesis (DS). However, its effectiveness for isthmic spondylolisthesis (IS) is still controversial. No current studies have directly compared perioperative and postoperative results including various radiological parameters between IS and DS after MIS TLIF.

PURPOSE

The purpose of this study is to compare the clinical and radiological results between isthmic and degenerative spondylolisthesis after MIS TLIF.

METHODS

This is a retrospective study of 41 patients who underwent MIS TLIF for single-segment, grade 1 or 2 IS (n = 18) and DS (n = 23). The same surgical techniques and procedure were applied to both groups. Perioperative outcomes (operation time, blood loss, hospital stay, complications); clinical outcomes (visual analog scale [VAS], Oswestry Disability Index [ODI]); radiological parameters (disk height, degree of spondylolisthesis, slip angle, lumbar lordosis, segmental lordosis, sacropelvic parameters: pelvic incidence, sacral slope, pelvic tile); and fusion rates using computed tomography scanning were compared between groups at 1 year postoperatively.

RESULTS

There were no significantly different perioperative results between groups. Mean VAS and ODI scores improved significantly postoperatively in both groups but were not significantly different between groups at each follow-up point. Radiological parameters were not significantly different between groups except disk height and degree of spondylolisthesis. The disk heights were increased postoperatively (IS: 6.79-9.22 mm; DS: 8.18-8.97 mm) in both groups, and there were significant differences preoperatively. In addition, disk height restoration was greater for IS than DS (2.43 mm vs. 0.79 mm, P = 0.01). However, postoperative disk heights were not significantly different between groups. The degree of spondylolisthesis was significantly different between groups both preoperatively (16.77% vs. 11.33%, P < 0.01) and postoperatively (9.79% vs. 3.78%, P < 0.01). However, slip reduction was no different between groups (6.97 vs. 7.56%, P = 0.74). Fusion rates were not significantly different between groups.

CONCLUSIONS

MIS TLIF resulted in similar clinical outcomes when used to treat both isthmic and degenerative spondylolisthesis. Although disk height restoration was more effective for IS than DS, other radiological parameters including fusion rate were no different between groups. For both isthmic and degenerative spondylolisthesis, MIS TLIF can be a safe and effective surgical option.

Biologic response of degenerative living human nucleus pulposus cells to treatment with cytokines

PURPOSE

To investigate the molecular responses of various genes and proteins related to disc degeneration upon treatment with cytokines that affect disc-cell proliferation and phenotype in living human intervertebral discs (IVDs). Responsiveness to these cytokines according to the degree of disc degeneration was also evaluated.

MATERIALS AND METHODS

The disc specimens were classified into two groups: group 1 (6 patients) showed mild degeneration of IVDs and group 2 (6 patients) exhibited severe degeneration of IVDs. Gene expression was analyzed after treatment with four cytokines: recombinant human bone morphogenic protein (rhBMP-2), transforming growth factor-β (TGF-β), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α). Molecular responses were assessed after exposure of cells from the IVD specimens to these cytokines via real-time polymerase chain reaction and immunofluorescence staining.

RESULTS

mRNA gene expression was significantly greater for aggrecan, type I collagen, type II collagen, alkaline phosphatase, osteocalcin, and Sox9 in group 1 than mRNA gene expression in group 2, when the samples were not treated with cytokines. Analysis of mRNA levels for these molecules after morphogen treatment revealed significant increases in both groups, which were much higher in group 1 than in group 2. The average number of IVD cells that were immunofluorescence stained positive for alkaline phosphatase increased after treatment with rhBMP-2 and TGF-β in group 1.

CONCLUSION

The biologic responsiveness to treatment of rhBMP-2, TGF-β, TNF-α, and IL-1β in the degenerative living human IVD can be different according to the degree of degeneration of the IVD.

Burst Fractures as a Result of Attempted Suicide by Jumping

Objective

Jumping from high place for the purpose of suicide results in various damages to body area. A burst fracture of vertebrae is representative of them and we reviewed eight patients who were diagnosed with spinal burst fracture following suicide falling-down. The demographics, characteristics, performed operation, combined injuries, psychological past histories of the patients were analyzed.

Methods

A retrospective study was made of patients who are diagnosed with vertebral burst fracture from falling-down with the purpose of suicide admitted to department of neurosurgery of the author's hospital, covering the period between 2003 and 2012.

Results

Total eight patients were suicidal jumper. There were eleven vertebral burst fractures in eight patients and mean age was 26.5 years old. Seven patients already had psychological past history and there were various combined injuries except vertebrae burst fracture. The ankle fracture such as calcaneus, talus, navicular and malleolus was the most common injury and there were also various combined injury.

Conclusion

Suicidal jumper is different from incidental faller in some aspects because of different injury mechanism. For managing suicidal jumper, physician had to consider patients' age, affected site, psychiatric problem and combined injuries. Each department related to the injuries of patient have to cooperate each other with departments of psychiatry and rehabilitation from beginning to end.

Association between BMP-2 and COL6A1 gene polymorphisms with susceptibility to ossification of the posterior longitudinal ligament of the cervical spine in Korean patients and family members

COL6A1 and BMP-2 genes have been implicated in ossification of the posterior longitudinal ligament (OPLL) susceptibility in Japanese and Chinese Han populations. However, no study has yet investigated the DNA of unaffected family members of patients with OPLL. This study investigated differences in genetic polymorphisms of BMP-2 and COL6A1 between Korean patients with OPLL and their family members (with and without OPLL). A total of 321 subjects (110 patients with OPLL and 211 family members) were enrolled in the study. Associations between two single nucleotide polymorphisms (SNPs) of the BMP-2 gene (Ser37Ala and Ser87Ser) and two SNPs of COL6A1 [promoter (-572) and intron 33 (+20)] with susceptibility to OPLL of the cervical spine were investigated between the two groups (OPLL+ and OPLL-). Of the 321 subjects, 162 had cervical OPLL (50.4%; 110 patients, 52 family members). There was a familial tendency of OPLL in 34 of the 110 families (30.9%). Allele and haplotype frequencies of the four SNPs in the BMP-2 and COL6A1 genes did not differ significantly between the OPLL+ and OPLL- groups, even when excluding participants over 50 years of age. This is the first report identifying SNPs of COL6A1 and BMP-2 in Korean patients and family members with OPLL. Although allele and haplotype frequencies were similar with those of a previous study in Japanese and Chinese patients, unaffected family members also showed similar rates of these SNPs in the present study. These results suggest that these SNPs may not directly influence the expression of OPLL.

Unilateral versus bilateral percutaneous pedicle screw fixation in minimally invasive transforaminal lumbar interbody fusion

OBJECT

Clinical results for unilateral pedicle screw fixation after lumbar interbody fusion have been reported to be as good as those for bilateral instrumentation. However, no studies have directly compared unilateral and bilateral percutaneous pedicle screw fixation after minimally invasive surgery (MIS) for transforaminal lumbar interbody fusion (TLIF). The purpose of this study was to determine whether unilateral percutaneous pedicle screw fixation is comparable with bilateral percutaneous pedicle screw fixation in 1-segment MIS TLIF.

METHODS

This was a prospective randomized study of 53 patients who underwent unilateral or bilateral percutaneous pedicle screw fixation after MIS TLIF for 1-segment lumbar degenerative disc disease. Twenty-six patients were assigned to a unilateral percutaneous pedicle screw fixation group and 27 patients were assigned to a bilateral percutaneous pedicle screw fixation group. Operative time, blood loss, clinical outcomes (that is, Oswestry Disability Index [ODI] and visual analog scale [VAS] scores), complication rates, and fusion rates were assessed using CT scanning 2 years after surgical treatment.

RESULTS

The 2 groups were similar in age, sex, preoperative diagnosis, and operated level, and they did not differ significantly in the length of follow-up (27.5 [Group 1] vs 28.9 [Group 2] months) or clinical results. Both groups showed substantial improvements in VAS and ODI scores 2 years after surgical treatment. The groups differed significantly in operative time (unilateral 84.2 minutes; bilateral 137.6 minutes), blood loss (unilateral 92.7 ml; bilateral, 232.0 ml), fusion rate (unilateral 84.6%; bilateral 96.3%), and postoperative scoliotic change (unilateral 23.1%; bilateral 3.7%).

CONCLUSIONS

Unilateral and bilateral screw fixation after MIS TLIF produced similar clinical results. Although perioperative results were better with unilateral screw fixation, the long-term results were better with bilateral screw fixation, suggesting bilateral screw fixation is a better choice after MIS TLIF.

Spine surgeon's kinematics during discectomy, part II: operating table height and visualization methods, including microscope

PURPOSE

Surgeon spine angle during surgery was studied ergonomically and the kinematics of the surgeon's spine was related with musculoskeletal fatigue and pain. Spine angles varied depending on operation table height and visualization method, and in a previous paper we showed that the use of a loupe and a table height at the midpoint between the umbilicus and the sternum are optimal for reducing musculoskeletal loading. However, no studies have previously included a microscope as a possible visualization method. The objective of this study is to assess differences in surgeon spine angles depending on operating table height and visualization method, including microscope.

MATERIALS AND METHODS

We enrolled 18 experienced spine surgeons for this study, who each performed a discectomy using a spine surgery simulator. Three different methods were used to visualize the surgical field (naked eye, loupe, microscope) and three different operating table heights (anterior superior iliac spine, umbilicus, the midpoint between the umbilicus and the sternum) were studied. Whole spine angles were compared for three different views during the discectomy simulation: midline, ipsilateral, and contralateral. A 16-camera optoelectronic motion analysis system was used, and 16 markers were placed from the head to the pelvis. Lumbar lordosis, thoracic kyphosis, cervical lordosis, and occipital angle were compared between the different operating table heights and visualization methods as well as a natural standing position.

RESULTS

Whole spine angles differed significantly depending on visualization method. All parameters were closer to natural standing values when discectomy was performed with a microscope, and there were no differences between the naked eye and the loupe. Whole spine angles were also found to differ from the natural standing position depending on operating table height, and became closer to natural standing position values as the operating table height increased, independent of the visualization method. When using a microscope, lumbar lordosis, thoracic kyphosis, and cervical lordosis showed no differences according to table heights above the umbilicus.

CONCLUSION

This study suggests that the use of a microscope and a table height above the umbilicus are optimal for reducing surgeon musculoskeletal fatigue.

Changes in spinal canal diameter and vertebral body height with age

PURPOSE

All structures of the spine, including the spinal canal, change continuously with age. The purpose of this study was to determine how the spinal canal of the lumbar spine changes with age. The L4/5 is the most common site of spinal stenosis and has the largest flexion-extension motion, whereas the T5/6 has the least motion. Therefore, we measured the spinal canal diameter and vertebral body height at T5, T6, L4, and L5 with age.

MATERIALS AND METHODS

This was a retrospective study of aged 40 to 77 years. We reviewed whole spine sagittal MRIs of 370 patients with lumbar spinal stenosis (LSS) (Group 2) and 166 herniated cervical disc (HCD) (Group 1). Each group was divided into four age groups, and demographic parameters (age, gender, height, weight, BMI), the mid-spinal canal diameter, and mid-vertebrae height at T5, T6, L4, L5 were compared. Within- and between-group comparisons were made to evaluate changes by age and correlations were carried out to evaluate the relationships between all parameters.

RESULTS

Height, weight, and all radiologic parameters were significantly lower in Group 2 than Group 1. Group 1 did not show any differences, when based on age, but in Group 2, height, weight, and T6, L4, and L5 height were significantly decreased in patients in their 70's than patients in their 40's, except for spinal canal diameter. Age was associated with all parameters except spinal canal diameter.

CONCLUSION

Vertebral height decreased with age, but spinal canal diameter did not change in patients with either LSS or HCD. Mid-spinal canal diameter was not affected by aging.

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

PURPOSE

It is well known that arthrodesis is associated with adjacent segment degeneration (ASD). However, previous studies were performed with simple radiography or CT. MRI is most sensitive in assessing the degenerative change of a disc, and this is the first study about ASD by radiography, CT and MRI. We sought to factors related to ASD at cervical spine by an MRI and CT, after anterior cervical spine surgery.

MATERIALS AND METHODS

This is a retrospective cross-sectional study of cervical disc herniation. Patients of cervical disc herniation with only radiculopathy were treated with either arthroplasty (22 patients) or ACDF with cage alone (21 patients). These patients were required to undergo MRI, CT and radiography preoperatively, as well as radiography follow-up for 3 months and 1 year, and we conducted a cross-sectional study by MRI, CT and radiography including clinical evaluations 5 years after. Clinical outcomes were assessed using VAS and NDI. The fusion rate and ASD rate, and radiologic parameters (cervical lordosis, operated segmental height, C2-7 ROM, operated segmental ROM, upper segmental ROM and lower segmental ROM) were measured.

RESULTS

The study groups were demographically similar, and substantial improvements in VAS (for arm) and NDI (for neck) scores were noted, and there were no significant differences between groups. Fusion rates were 95.2% in the fusion group and 4.5% in the arthroplasty group. ASD rates of the fusion and arthroplasty groups were 42.9 and 50%, respectively. Among the radiologic parameters, operated segmental height and operated segmental ROM significantly decreased, while the upper segmental ROM significantly increased in the fusion group. In a comparative study between patients with ASD and without ASD, the clinical results were found to be similar, although preexisting ASD and other segment degeneration were significantly higher in the ASD group. C2-7 ROM was significantly decreased in ASD group, and other radiologic parameters have no significant differences between groups.

CONCLUSION

The ASD rate of 46.5% after ACDF or arthroplasty, and arthroplasty did not significantly lower the rate of ASD. ASD occurred in patients who had preexisting ASD and in patients who also had other segment degeneration. ASD may be associated with a natural history of cervical spondylosis rather than arthrodesis.

What is the importance of "halo" phenomenon around bone cement following vertebral augmentation for osteoporotic compression fracture?

We investigated the importance, risk factors, and clinical course of the radiolucent "halo" phenomenon around bone cement following vertebral augmentation for osteoporotic compression fracture. Preoperative osteonecrosis and a lump cement pattern were the most important risk factors for the peri-cement halo phenomenon, and it was associated with vertebral recollapse.

INTRODUCTION

We observed a newly developed radiolucent area around the bone cement following vertebral augmentation for osteoporotic compression fractures. Here, we describe the importance of the peri-cement halo phenomenon, as well as any associated risk factors and long-term sequelae.

METHODS

In total, 175 patients (202 treated vertebrae) were enrolled in this study. The treated vertebrae were subdivided into two groups: Group A (with halo, n = 32) and Group B (without halo, n = 170), and the groups were compared with respect to multiple preoperative (age, sex, BMD, preoperative osteonecrosis) and perioperative factors (operative approach: vertebroplasty or kyphoplasty; cement distribution pattern; cement leakage; cement volume), and postoperative results (VAS score, recollapse). Logistic regression analysis was used to evaluate the relationship between the incidence of the peri-cement halo and all of the parameters described above.

RESULTS

Rates of osteonecrosis were also significantly higher in Group A than in Group B (62.5% vs. 31.2%, p < 0.05), and kyphoplasty (KP) was performed more frequently in Group A (43.8% vs. 17.6%, p < 0.05). Lump cement (93.8% vs. 30.6%, p < 0.05) and recollapse (78.1% vs. 24.7%, p < 0.05) were also more common among individuals in Group A. Logistic regression analysis also showed that preoperative osteonecrosis (OR = 3.679; 95% CI = 1.677-8.073; p = 0.001), KP (OR = 3.630; 95% CI = 1.628-8.095; p = 0.002), lump pattern (OR = 13.870; 95% CI = 2.907-66.188; p = 0.001), and vertebral recollapse (OR = 5.356; 95% CI = 1.897-15.122; p = 0.002) were significantly associated with peri-cement halo.

CONCLUSIONS

The peri-cement halo was found to be associated with vertebral recollapse, this sign likely represents a poor prognostic factor after vertebral augmentation for osteoporotic compression fractures.

A PET/CT-based Morphometric Study of Spinal Canal in Korean Young Adults: Anteroposterior Diameter from Cervical Vertebra to Sacrum

Objective

To establish normative data for spinal canal AP diameter from cervical vertebra to sacrum in the Korean young and to assess the exposed spinal canal after laminectomy which was related with restenosis by post-laminectomy membrane formation.

Methods

From PET/CT, axial bone-window CT of 83 young adults (20-29 years) were obtained, and we measured AP diameters of C3, C5, C7, T1, T4, T8, T12, L1, L3, L5 and S1. We also measured exposed AP diameter of C3, C5, C7, T1 and T2 above imaginary line for laminectomy.

Results

The shortest mean AP diameter was at C5 (14.5±1.5 mm), and the longest was at S1 (17.4±2.3 mm). AP diameter increased from C3 (14.6±1.1 mm) to T1 (16.1±1.2 mm) at cervical spine. In the thoracic spine, the diameter gradually decreased from T1 (16.1±1.2 mm) to T8 (14.6±1.3 mm) and increased to T12 (16.7±1.2 mm). The diameter decreased from L1 (16.7±1.3 mm) to L3 (15.7±1.9 mm), and it increased to S1 (17.4±2.3 mm) at lumbar spine. Exposed AP diameter above imaginary line for laminectomy was the longest at C3 (4.8±1.2 mm) and gradually decreased to T1 (3.3±0.9 mm) and T2 (0 mm).

Conclusions

Spinal AP diameter was the shortest in the mid-cervical area (C5) and increased to the upper thoracic area. From the upper thoracic vertebra, the diameter gradually decreased to the mid-thoracic vertebra (T8) and then increased to the lower thoracic vertebra. Lumbar vertebra also was similar with thoracic vertebra. Below T2, there was no exposed dural sac after laminectomy. This means that restenosis by post-laminectomy membrane formation can occur above T1.

Spine surgeon's kinematics during discectomy according to operating table height and the methods to visualize the surgical field

PURPOSE

The ergonomic problems for surgeons during spine surgery are an awkward body posture, repetitive movements, increased muscle activity, an overflexed spine, and a protracted time in a standing posture. The authors analyzed whole spine angles during discectomy. The objective of this study is to assess differences in surgeon whole spines angles according to operating table height and the methods used to visualize surgical field.

MATERIALS AND METHODS

A cohort of 12 experienced spine surgeons was enrolled. Twelve experienced spine surgeons performed discectomy using a spine surgery simulator. Three different methods were used to visualize the surgical field (naked eye, loupe, and out of loupe) and three different operating table heights. Whole spine angles were compared for three different views during discectomy simulation; midline, ipsilateral, and contralateral. A 16-camera optoelectronic motion analysis system was used, and 16 markers were placed from head to pelvis. Lumbar lordosis, thoracic kyphosis, cervical lordosis, and occipital angle were compared at the different operating table heights, while using the three visualization methods, with natural standing position.

RESULTS

Whole spine angles were significantly different for visualization methods. Lumbar lordosis, cervical lordosis, and occipital angle were closer to natural standing values when discectomy was performed with a loupe, but most measures differed from natural standing values when performed out of loupe. Thoracic kyphosis was also similar to the natural standing position during discectomy using a loupe, but differed from the natural standing position when performed with naked eye. Whole spine angles were also found to differ from the natural standing position according to operating table height, and became closer to natural standing position values as operating table height increased, when simulation was conducted with loupe.

CONCLUSION

This study suggests that loupe use and a table height midpoint between the umbilicus and sternum are optimal for reducing surgeon musculoskeletal fatigue.

The relevance of intramedullary high signal intensity and gadolinium (Gd-DTPA) enhancement to the clinical outcome in cervical compressive myelopathy

PURPOSE

We prospectively investigated whether high intramedullary SI and contrast [gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA)] enhancement in magnetic resonance imaging (MRI) are associated with postoperative prognosis in cervical compressive myelopathy (CCM) patients.

METHODS

Seventy-four patients with ventral cord compression at one or two levels underwent anterior cervical discectomy and fusion (ACDF) for CCM between March 2006 and June 2009. The mean follow-up period was 39.7 months (range, 12.7-55.7 months). The cervical cord compression ratio and clinical outcomes were measured using Japanese Orthopedic Association (JOA) scores for cervical myelopathy. Patients were classified into three groups based on the SI change in T2WI, T1-weighted images (T1WI), and contrast (Gd-DTPA) enhancement.

RESULTS

The mean preoperative and postoperative JOA scores were 10.5 ± 2.9 and 15.0 ± 2.1 (P < 0.05), respectively. The mean recovery ratio of the JOA score was 70.9 ± 20.2%. There were statistically significant differences in postoperative JOA and recovery ratio among three groups. However, post-surgical neurological outcomes were not associated with age, symptom duration, preoperative JOA, and cord compression.

CONCLUSIONS

We found that intramedullary SI change is a poor prognostic factor and the intramedullary contrast (Gd-DTPA) enhancement on preoperative MRI should be viewed as the worst predictor of surgical outcomes in cervical myelopathy. Contrast (Gd-DTPA) enhancement and postoperative MRI are useful for identifying the prognosis of patients with poor neurological recovery.

Survival rate and neurological outcome after operation for advanced spinal metastasis (Tomita's classification > or = type 4)

PURPOSE

We investigated whether primary malignancy entities and the extent of tumor resection have an effect on the survival rate and neurological improvement in patients with spinal metastases that extend beyond the vertebral compartment (Tomita's classification > or = type 4).

MATERIALS AND METHODS

We retrospectively reviewed 87 patients with advanced spinal metastasis who underwent surgery. They were divided into groups 1 and 2 according to whether they responded to adjuvant therapy or not, respectively. They were subdivided according to the extent of tumor resection: group 1, gross total resection (G1GT); group 1, subtotal resection (G1ST); group 2, gross total resection (G2GT); and group 2, subtotal resection (G2ST). The origin of the tumor, survival rate, extent of resection, and neurological improvement were analyzed.

RESULTS

Group 1 had a better survival rate than group 2. The G1GT subgroup showed a better prognosis than the G1ST subgroup. In group 2, the extent of tumor resection (G2GT vs. G2ST) did not affect survival rate. In all subgroups, neurological status improved one month after surgery, however, the G2ST subgroup had worsened at the last follow-up. There was no local recurrence at the last follow-up in the G1GT subgroup. Four out of 13 patients in the G2GT subgroup showed a local recurrence of spinal tumors and progressive worsening of neurological status.

CONCLUSION

In patients with spinal metastases (Tomita's classification > or = type 4), individuals who underwent gross total resection of tumors that responded to adjuvant therapy showed a higher survival rate than those who underwent subtotal resection. For tumors not responding to adjuvant therapy, we suggest palliative surgical decompression.

Load sharing mechanism across graft-bone interface in static cervical locking plate fixation

OBJECTIVE

This study is a retrospective clinical study over more than 4 years of follow up to understand the mechanism of load sharing across the graft-bone interface in the static locking plate (SLP) fixation compared with non-locking plate (NLP).

METHODS

Orion locking plates and Top non-locking plates were used for SLP fixation in 29 patients and NLP fixation in 24 patients, respectively. Successful interbody fusion was estimated by dynamic X-ray films. The checking parameters were as follows : screw angle (SA) between upper and lower screw, anterior and posterior height of fusion segment between upper and lower endplate (AH & PH), and upper and lower distance from vertebral endplate to the end of plate (UD & LD). Each follow-up value of AH and PH were compared to initial values. Contributions of upper and lower collapse to whole segment collapse were estimated.

RESULTS

Successful intervertebral bone fusion rate was 100% in the SLP group and 92% in the NLP group. The follow-up mean value of SA in SLP group was not significantly changed compared with initial value, but follow-up mean value of SA in NLP group decreased more than those in SLP group (p=0.0067). Statistical analysis did not show a significant difference in the change in AH and PH between SLP and NLP groups (p>0.05). Follow-up AH of NLP group showed more collapse than PH of same group (p=0.04). The upper portion of the vertebral body collapsed more than the lower portion in the SLP fixation (p=0.00058).

CONCLUSION

The fused segments with SLP had successful bone fusion without change in initial screw angle, which was not observed in NLP fixation. It suggests that there was enough load sharing across bone-graft interface in SLP fixation.

Recollapse of previous vertebral compression fracture after percutaneous vertebroplasty

This study was undertaken to investigate the incidence rate, characteristics, and predisposing factors associated with recollapse of the same vertebrae after percutaneous vertebroplasty (PVP). Recollapse of the same vertebra after PVP is the one of the complications of the procedure, and the incidence rate in our study was 3.21%. The most important predisposing factor was pre-operative osteonecrosis. Recollapse was not related to trauma.

INTRODUCTION

PVP using polymethylmethacrylate has become a popular treatment for osteoporotic vertebral compression fracture. Recollapse of the same vertebrae after PVP has rarely been reported. This study was undertaken to investigate the incidence, characteristics, and predisposing factors associated with recollapse of the same vertebrae after PVP.

METHODS

Eleven patients (seven females and four males; mean age, 69.91 +/- 5.49 years), out of a total of 343 patients, developed recollapse of the same vertebra after PVP. The 11 patients who developed recollapse comprised the "recollapse group", while the remaining 332 patients comprised the "well-maintained group".

RESULTS

Pre-operative magnetic resonance imaging revealed that the incidence of osteonecrosis was significantly higher in the recollapse group than the well-maintained group (p < 0.05). The degree of re-expansion of the compressed vertebral body after PVP was significantly higher in the recollapse group than in the well-maintained group (p < 0.05).

CONCLUSIONS

The most important predisposing factor for recollapse was pre-operative osteonecrosis. Recollapse was not related to trauma. Osteoporotic vertebral compression fracture with osteonecrosis or pseudoarthrosis has been regarded as a relative indication for PVP; however, the findings of this study suggest that this disease category may be a relative contraindication for PVP.

A comparison of three cell types as potential candidates for intervertebral disc therapy: annulus fibrosus cells, chondrocytes, and bone marrow derived cells

OBJECTIVES

Candidate cell types for disc cell transplantation therapy include anulus fibrosus (AF) cells, chondrocytes, and bone marrow derived cells (BMDCs). We compared the disc matrix production in these three types of cells, before and after stimulation with rhBMP-2. There is no study extant that compares these three cell types to determine the best candidate for the disc cell therapy.

METHODS

AF cells, chondrocytes, and BMDCs (iliac crest and femur) were isolated and grown in monolayer. They were treated for 3 days with rhBMP-2. After 3 days, proteoglycan (sGAG) content in the media was quantified. The results were normalized by cell numbers. The mRNA expression of aggrecan, type I collagen, and type II collagen was measured using real-time PCR. Each cell type was also cultured in chamber slides and immunostained for aggrecan, type I collagen, and type II collagen after 3 days of treatment with rhBMP-2.

RESULTS

(1) Without rhBMP-2 the chondrocytes produced more proteoglycan (sGAG) as compared to the other two cell types (AF cells and BMDCs). After stimulation with rhBMP-2 the chondrocytes produce even more proteoglycan than the other two cell types. (2) As compared to the other two cell types, in terms of mRNA expression, the chondrocytes expressed more aggrecan, type I collagen, and type II collagen before stimulation with rhBMP-2. After rhBMP-2 stimulation, the chondrocytes expressed even more aggrecan, type I collagen, and type II collagen in proportion to the concentration of rhBMP-2. For the BMDCs there were no changes in type I and II collagen. (3) rhBMP-2 stimulation produced increases in the protein levels of aggrecan, type I and II collagen in all three types of cells.

CONCLUSIONS

On balance, according to these results, it would seem that chondrocytes are the best candidate for the disc cell therapy.

Can TGF-beta1 and rhBMP-2 act in synergy to transform bone marrow stem cells to discogenic-type cells?

INTRODUCTION

The recombinant human bone morphogenic protein-2 (rhBMP-2) is known to increase the proteoglycan production and chondrogenic gene expression in the disc cells. The transforming growth factor-beta 1 (TGF-beta(1)) can transform the bone marrow stem cells (BMDCs) into the disc-like cells.

MATERIALS AND METHODS

We carried out an experiment to determine if TGF-beta(1) and rhBMP-2 can act in synergy on BMDCs by increasing the production of sulfated-glycosaminoglycan (sGAG) and affecting the mRNA expression of aggrecan, type I collagen, and type II collagen. The BMDCs were isolated from the iliac crest and femur of a New Zealand white rabbit (1 year). The BMDCs were culured in monolayer and treated for 6 days with TGF-beta(1) 10 ng/ml (group 1), rhBMP-2 200 ng/ml (group 2), and both TGF-beta(1) 10 ng/ml and rhBMP-2 200 ng/ml (group 3: the combined group) in Dulbecco's modified Eagle medium/F-12 with 1% fetal bovine serum. After 6 days, the sGAG content in the media was quantified using 1,9-dimethylmethylene blue staining and the mRNA expression of aggrecan, type I collagen, type II collagen, Sox-9, BMP-2, and BMP-7 were measured with the real-time PCR. The same BMDCs were also cultured in the chamber slide at 3 x 10(4) cells/chamber. After 6 days treatment, the treated cells were immunofluorescence stained with aggrecan, type I collagen, type II collagen, anti-BMP-2, anti-BMP-7 antibodies. After that, we compared the number of positive immunofluorescence stained cells with fluorescence microscope. The sGAG production and mRNA expression for each group were normalized against the same parameters for a non-treatment group.

RESULTS AND DISCUSSION

The sGAG production was increased 1.15*, 1.34*, and 1.45* times in the TGF-beta(1) 10 ng/ml group, the rhBMP-2 200 ng/ml group, and the combined group respectively. The mRNA expression of aggrecan was increased 1.28, 3.42*, and 5.34* times, the mRNA expression of type I collagen was increased 0.86, 1.09, 1.17 times, the mRNA expression of type II collagen was increased 3.58*, 3.77*, and 10.78* times, the mRNA expression of Sox-9 was increased 1.29, 2.45, 2.75* times, the mRNA expression of BMP-2 was increased 1.14, 2.07, 4.43* times, and the mRNA expression of BMP-7 was increased 1.16, 1.49, 1.97* times, respectively for each group (* indicates p < 0.05). On the immunofluorescence staining of antibodies, the average positively immunofluorescence stained cells number for aggrecan were 4.2, 15.8*, 10*, and 22* according to the non-treatment group, TGF-beta(1) 10 ng/ml group, rhBMP-2 200 ng/ml group, and the combined group respectively. The average positively immunofluorescence stained cells number for type I collagen were 7, 14.2*, 9.2*, 17.4* and the average positively immunofluorescence stained cells number for type II collagen were 8.5, 28.25*, 20.25*, 42.25* and the average positively immunofluorescence stained cells number for anti-BMP-2 were 5, 16.75*, 8.75*, 27.25* and the average positively immunofluorescence stained cells number for anti-BMP-7 were 3.25, 7.5*, 8.75*, 15.25* (* indicates p < 0.05).

CONCLUSIONS

Both TGF-beta(1) and rhBMP-2 alone, can increase proteoglycan production in the BMDCs. However, if they were used in combination, there is a synergistic effect. Similarly, the mRNA expressions of both aggrecan, type II collagen, Sox-9, BMP-2, and BMP-7 except for type I collagen were increased significantly when TGF-beta(1) and rhBMP-2 were combined. The positive immunofluorescence stained cell numbers for aggrecan, type I, II collagen, BMP-2 and BMP-7 were also increased after each TGF-beta(1) and rhBMP-2 treatment, and also more increased significantly in the aggrecan, type I, II collagen, BMP-2, and 7 when they were used jointly.

The AdLMP-1 transfection in two different cells; AF cells, chondrocytes as potential cell therapy candidates for disc degeneration

BACKGROUND

LMP-1 is known to increase proteoglycan production through the upregulating the BMPs and it is also known that BMP-2 acts on anulus fibrosus cells and chondrocytes to increase proteoglycan production.

METHOD

We carried out an experiment, the effect of AdLMP-1 transfection on AF cells and chondrocytes in the production of sulfated-glycosaminoglycans, mRNA expression (aggrecan, type I, II collagen, LMP-1, BMP-2, and BMP-7), and immunofluorescence staining. AF cells and chondrocytes were grown in monolayer and treated for 6 days with AdLMP1-green fluorescence protein (GFP) (10, 20, and 30 multiplicity of infection [MOI]). After 6 days, the sGAG content in the media was quantified using 1,9-dimethylmethylene blue staining. The mRNA expression was measured with real-time PCR after 20 MOI infection of AdLMP1-GFP. The each cells treated with 20 MOI infection of AdGFP was used as a control group for the mRNA expression. The each cell group was immunofluorescence stained with each antibodies in the chamber slide at 3 x 10(4) cells/chamber.

FINDINGS

1) The sGAG production was maximum in 20 MOI AdLMP1-GFP infection on the AdLMP-1 treatment for both of AF cells and chondrocytes. 2) The mRNA expression of aggrecan, type I collagen, type II collagen, LMP-1, BMP-2, and BMP-7 is increased in both AF cells and chondrocytes in 20 MOI AdLMP1-GFP infection. 3) On the immunofluorescence staining results, the positive immunofluorescence stained cell numbers are increased after 20 MOI AdLMP1-GFP infection concordant with upregulation of mRNA expression.

CONCLUSIONS

The AdLMP-1 treatments in AF cells and chondrocytes may be useful for cell transplantation therapy in disc degeneration.

Prevalence of osteoporosis in patients requiring spine surgery: incidence and significance of osteoporosis in spine disease

The purpose of this study is to evaluate the incidence of osteoporosis in patients requiring spine surgery. Among patients older than 50 years, the rate of osteoporosis in males was 14.5% and the rate osteoporosis in females was 51.3%. We strongly recommend an evaluation and treatment for osteoporosis in the patients requiring spine surgery, especially in females over 50 years old.

INTRODUCTION

Because lifespan is increasing, there is an increase in the incidence of osteoporosis in elderly spine surgery patients. The osteoporosis may adversely influence the fusion rate and the surgical outcome. The purpose of this study is to evaluate the incidence of osteoporosis in patients requiring spine surgery.

METHODS

A total of 1,321 patients underwent spine surgeries at our institute from January 1, 2005 to December 31, 2005. Among them, there were 562 patients (42.5%) younger than 50 years old, and 759 patients (57.6%) older than 50 years old. Prior to operation, we evaluated the patients for osteoporosis on both the femur head and lumbar spine by measuring the bone mineral density (BMD) by the dual-energy X-ray absorptiometry (DXA). Based on the World Health Organization (WHO) criteria for osteoporosis, we chose the T-score to determine normal (>-1), osteopenia (-1>or=, >-2.5), and osteoporosis (<or=-2.5). Among the 562 patients younger than 50 years, DXA was performed in 22 (3.9%) patients and there were 13 (2.3%) cases of osteopenia and 2 (0.3%) cases of osteoporosis.

RESULTS

Among 759 patients older than 50 years, DXA was performed on 516 (68.0%) patients, 193 males and 323 females. Among the male patients, there were 89 (46.1%) patients with osteopenia and 28 (14.5%) with osteoporosis. Among the female patients, there were 134 (41.4%) with osteopenia and 166 (51.3%) with osteoporosis. The incidence of osteoporosis was higher in female patients and significantly increased with increasing age. Among 759 patients older than 50 years, 676 patients underwent a major spine operation with or without fusion. Among these patients, DXA was performed in 446 (66.0%) patients and there were 207 (46.4%) patients with osteopenia and 139 (31.1%) with osteoporosis.

CONCLUSIONS

The patients over 50 year-old who need spine operation have osteoporosis often. In conclusion, the number of spine operations in elderly patients is increasing and the incidence of osteoporosis in spine surgery patients is also increasing. We strongly recommend an evaluation for osteoporosis and post-operative treatment for osteoporosis in patients over 50 years old, especially for female patients.

New prognostic factors for adjacent-segment degeneration after one-stage 360° fixation for spondylolytic spondylolisthesis: special reference to the usefulness of pelvic incidence angle

Object.

The purpose of this study was to evaluate the correlation between adjacent-segment degeneration (ASD) and pelvic parameters in the patients with spondylolytic spondylolisthesis. Sagittal balance is the most important risk and prognostic factor in the development of ASD. The pelvic incidence angle (PIA) is an important anatomical parameter in determining the sagittal curvature of the spine and in the individual variability of the sacral slope and the lordotic curve. Thus, the authors evaluated the relationship between the pelvic parameters and the ASD.

Methods.

Among 132 patients with spondylolytic spondylolisthesis who underwent surgery at their institution, the authors selected patients in whom a one-stage, single-level, 360° fixation procedure was performed for Grade I spondylolisthesis and who underwent follow-up for more than 1 year. Parameters in 34 patients satisfied these conditions. Of the 34 patients, seven had ASD (Group 1) and 27 patients did not have ASD (Group 2). The investigators measured degree of spondylolisthesis, lordotic angle, sacral slope angle (SSA), pelvic tilt angle (PTA), PIA, and additional parameters pre-and postoperatively. The radiographic data were reviewed retrospectively.

Results.

The population consisted of nine men and 25 women whose mean age was 48.9 ± 9 years (± standard deviation) (range 28–65 years). Seven patients developed ASD after undergoing fusion. Of all the parameters, pre-and postoperative degree of spondylolisthesis, segmental lordosis, lordotic angle, SSA, preoperative PTA, and pre-operative PIA did not differ significantly between the two groups; only postoperative PTA and PIA were significantly different.

Conclusions.

The development of ASD is closely related to postoperative PIA and PTA, not preoperative PIA and PTA. The measurement of postoperative PIA can be used as a new indirect method to predict the ASD.

Contributing factors affecting the prognosis surgical outcome for thoracic OLF

The thoracic ossification of ligamentum flavum (OLF) is a disease that produces spastic paraparesis, and there are various factors that may affect the surgical outcome of thoracic OLF patients. The authors of this study treated 19 of these thoracic OLF patients from 1998 to 2002, and retrospectively reviewed the patients' age, sex, symptom duration, involved disease level, preoperative clinical features, neurological findings, radiological findings, the other combined spinal diseases and the surgical outcomes. There were excellent or good surgical outcomes in 16 patients, but 3 patients did not improve after thoracic OLF surgery: this included 1 patient, whose motor function worsened after decompressive thoracic OLF surgery. The favorable contributing factors of surgical outcome in thoracic OLF are a short preoperative symptom duration, single-level lesion, and unilateral lesion type on CT axial scan. On the contrary, the poor prognostic factors are beak type lesion and intramedullary signal changes on T(2)-weighted sagittal MRI. The complete preoperative evaluation including radiologic findings will provide valuable aid in presuming the surgical outcome for the thoracic OLF patients.