Radiographic and clinical outcomes of robot-assisted pedicle screw instrumentation for adolescent idiopathic scoliosis

Introduction

Pedicle screw instrumentation (PSI) serves as the widely accepted surgical treatment for adolescent idiopathic scoliosis (AIS). The accuracy of screw positioning has remarkably improved with robotic assistance. Nonetheless, its impact on radiographic and clinical outcomes remains unexplored. This study aimed to investigate the radiographic and clinical outcomes of robot-assisted PSI vs. conventional freehand method in AIS patients.

Methods

Data of AIS patients who underwent PSI with all pedicle screws between April 2013 and March 2022 were included and retrospectively analyzed; those with hybrid implants were excluded. Recruited individuals were divided into the Robot-assisted or Freehand group according to the technique used. Radiographic parameters and clinical outcome measures were documented.

Results

In total, 50 patients (19, Freehand group; 31, Robot-assisted group) were eligible, with an average age and follow-up period of 17.6 years and 60.2 months, respectively, and female predominance (40/50, 80.0%). The correction rates of Cobb's angles for both groups were significant postoperatively. Compared to freehand, the robot-assisted technique achieved a significantly reduced breech rate and provided better trunk shift and radiographic shoulder height correction with preserved lumbar lordosis, resulting in significantly improved visual analog scale scores for back pain from the third postoperative month.

Conclusion

Overall, robot-assisted PSI provides satisfactory radiographic and clinical outcomes in AIS patients.

Optimizing Spinal Fusion Cage Design to Improve Bone Substitute Filling on Varying Disc Heights: A 3D Printing Study

The success of spinal fusion surgery relies on the precise placement of bone grafts and minimizing scatter. This study aims to optimize cage design and bone substitute filling methods to enhance surgical outcomes. A 3D printed lumbar spine model was utilized to implant 3D printed cages of different heights (8 mm, 10 mm, 12 mm, and 14 mm) filled with BICERA® Bone Graft Substitute mixed with saline. Two filling methods, SG cage (side hole for grafting group, a specially designed innovative cage with side hole, post-implantation filling) and FP cage (finger-packing group, pre-implantation finger packing, traditional cage), were compared based on the weight of the implanted bone substitute. The results showed a significantly higher amount of bone substitute implanted in the SG cage group compared to the FP cage group. The quantity of bone substitute filled in the SG cage group increased with the height of the cage. However, in the FP cage group, no significant difference was observed between the 12 mm and 14 mm subgroups. Utilizing oblique lumbar interbody fusion cages with side holes for bone substitute filling after implantation offers several advantages. It reduces scatter and increases the amount of implanted bone substitute. Additionally, it effectively addresses the challenge of insufficient fusion surface area caused by gaps between the cage and endplates. The use of cages with side holes facilitates greater bone substitute implantation, ultimately enhancing the success of fusion. This study provides valuable insights for future advancements in oblique lumbar interbody fusion cage design, highlighting the effectiveness of using cages with side holes for bone substitute filling after implantation.

Comparative Biomechanical Analysis of Unilateral, Bilateral, and Lateral Pedicle Screw Implantation in Oblique Lumbar Interbody Fusion: A Finite Element Study

Oblique lumbar interbody fusion (OLIF) can be combined with different screw instrumentations. The standard screw instrumentation is bilateral pedicle screw fixation (BPSF). However, the operation is time consuming because a lateral recumbent position must be adopted for OLIF during surgery before a prone position is adopted for BPSF. This study aimed to employ a finite element analysis to investigate the biomechanical effects of OLIF combined with BPSF, unilateral pedicle screw fixation (UPSF), or lateral pedicle screw fixation (LPSF). In this study, three lumbar vertebra finite element models for OLIF surgery with three different fixation methods were developed. The finite element models were assigned six loading conditions (flexion, extension, right lateral bending, left lateral bending, right axial rotation, and left axial rotation), and the total deformation and von Mises stress distribution of the finite element models were observed. The study results showed unremarkable differences in total deformation among different groups (the maximum difference range is approximately 0.6248% to 1.3227%), and that flexion has larger total deformation (5.3604 mm to 5.4011 mm). The groups exhibited different endplate stress because of different movements, but these differences were not large (the maximum difference range between each group is approximately 0.455% to 5.0102%). Using UPSF fixation may lead to higher cage stress (411.08 MPa); however, the stress produced on the endplate was comparable to that in the other two groups. Therefore, the length of surgery can be shortened when unilateral back screws are used for UPSF. In addition, the total deformation and endplate stress of UPSF did not differ much from that of BPSF. Hence, combining OLIF with UPSF can save time and enhance stability, which is comparable to a standard BPSF surgery; thus, this method can be considered by spine surgeons.

Surgical outcomes of anterior lumbar interbody fusion in revision lumbar interbody fusion surgery

BACKGROUNDS

Anterior lumbar interbody fusion (ALIF) is an attractive option for revision lumbar interbody fusion as it provides wide access for implant removal and accommodation of large interbody grafts for fusion. However, revision lumbar interbody fusion surgery has not been found to result in significantly better functional outcomes compared with other approaches. To date, no prognostic factors of anterior lumbar interbody fusion in revision lumbar interbody fusion have been reported. In this study, we investigated the surgical results and possible prognostic factors of anterior lumbar interbody fusion in revision lumbar interbody fusion.

METHODS

Patients who received revision interbody fusion surgery between January 2010 and May 2018 in our hospital were reviewed. Clinical outcomes were determined according to whether the VAS score improvement in back pain and leg pain reached the minimum clinically important difference (MCID) and Macnab criteria. Radiographic outcomes were assessed with fusion rate, preoperative, and postoperative lumbar lordosis. Operative-relative factors that may affect clinical outcomes, such as BMI, existence of cage migration, cage subsidence, pseudarthrosis, previous procedure, and number of fusion segments, were collected and analyzed.

RESULTS

A total of 22 consecutive patients who received ALIF for revision interbody fusion surgery were included and analyzed. There were 9 men and 13 women with a mean age at operation of 56 years (26-78). The mean follow-up was 73 months (20-121). The minimal clinically important difference (MCID) was reached in 11 (50%) of the patients for back pain and 14 (64%) for leg pain. According to the modified Macnab criteria, 73% of the patients in this study had successful outcomes (excellent or good). The pain and lumbar lordosis had significant improvement (P < 0.05). Preoperative fusion segment ≥ 2 was shown to be a poor prognostic factor for back pain improvement reaching MCID (P = 0.043).

CONCLUSIONS

ALIF has proven effective for revision lumbar fusion surgery, yielding positive clinical and radiographic results. However, having two or more preoperative fusion segments can negatively impact back pain improvement.

LEVEL OF EVIDENCE

IV.

Comparison of radiographic and clinical outcomes between ALIF, OLIF, and TLIF over 2-year follow-up: a comparative study

BACKGROUND

Regarding the increasing adoption of oblique lateral interbody fusion (OLIF) for treating degenerative lumbar disorders, we aimed to evaluate whether OLIF, one of the options for anterolateral approach lumbar interbody fusion, demonstrate clinical superiority over anterior lumbar interbody fusion (ALIF) or posterior approach, represented by transforaminal lumbar interbody fusion (TLIF).

METHODS

Patients who received ALIF, OLIF, and TLIF for symptomatic degenerative lumbar disorders during the period 2017-2019 were identified. Radiographic, perioperative, and clinical outcomes were recorded and compared during 2-year follow-up.

RESULTS

A total of 348 patients with 501 correction levels were enrolled in the study. Fundamental sagittal alignment profiles were substantially improved at 2-year follow-up, particularly in the anterolateral approach (A/OLIF) group. The Oswestry disability index (ODI) and EuroQol-5 dimension (EQ-5D) in the ALIF group were superior when compared to the OLIF and TLIF group 2-year following surgery. However, comparisons of VAS-Total, VAS-Back, and VAS-Leg revealed no statistically significance across all approaches. TLIF demonstrated highest subsidence rate of 16%, while OLIF had least blood loss and was suitable for high body mass index patients.

CONCLUSIONS

Regarding treatment for degenerative lumbar disorders, ALIF of anterolateral approach demonstrated superb alignment correction and clinical outcome. Comparing to TLIF, OLIF possessed advantage in reducing blood loss, restoring sagittal profiles and the accessibility at all lumbar level while simultaneously achieving comparable clinical improvement. Patient selection in accordance with baseline conditions, and surgeon preference both remain crucial issues circumventing surgical approach strategy.

Correlation of Foraminal Parameters with Patient-Reported Outcomes in Patient with Degenerative Lumbar Foraminal Stenosis

The relationship between quantitative anatomic parameters in MRI and patient-reported outcomes (PROs) before and after surgery in degenerative lumbar foraminal stenosis remains unknown. We included 58 patients who underwent transforaminal lumbar interbody fusion (TLIF) for single-level degenerative disc disease with foraminal stenosis between February 2013 and June 2020. PROs were evaluated using the visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D). The foraminal parameters assessed using preoperative MRI included foraminal height, posterior intervertebral disc height, superior and inferior foraminal width, and foraminal area. The correlation between foraminal parameters and PROs before operation, at 1 year follow-up, and change from baseline were assessed. The associations between the aforementioned parameters were examined using linear regression analysis. The analysis revealed that among these parameters, superior foraminal width was found to be significantly correlated with ODI and EQ-5D at the 1 year follow-up and with change in ODI and EQ-5D from baseline. The associations remained significant after adjustment for confounding factors including age, sex, body mass index, and duration of hospital stay. The results indicated that in degenerative lumbar foraminal stenosis, decreased superior foraminal width was associated with better improvement in disability and quality of life after TLIF.

Pre-operative anemia was associated with all-cause mortality in patients with vertebral fracture who underwent percutaneous vertebroplasty

PURPOSE

We investigated the association between pre-operative anemia and long-term all-cause mortality in patients with vertebral fracture who underwent a vertebroplasty.

MATERIALS AND METHODS

We retrospectively selected patients who were admitted for vertebroplasty for vertebral compression fracture between 2013 and 2020. Patients who had pathologic fractures or had no assessment of bone mineral density were excluded. Relevant information was collected from electronic medical records. Patients' survival status was confirmed at the end of March 2021. Cox-proportional hazard models were conducted to examine the effects of anemia (<12 g/dL vs. ≥12 g/dL) and pre-operative hemoglobin levels (as a continuous variable) on all-cause mortality with multivariate adjustments.

RESULTS

A total of 167 patients were analyzed (mean age 75.8 ± 9.3 years, male 25.7%). After a median follow-up duration of 2.1 years, pre-operative anemia (hemoglobin <12 g/dL vs. ≥12 g/dL) was independently associated with a higher risk of all-cause mortality (hazard ratio 2.762, 95% CI 1.184 to 6.442, p = 0.019). An increase in pre-operative hemoglobin was associated with a lower risk of all-cause mortality after multivariate adjustment (hazard ratio 0.775, 95% CI 0.606 to 0.991, p = 0.042).

CONCLUSION

Pre-operative anemia (<12 g/dL) was independently associated with survival outcome among patients with vertebral compression fractures who underwent vertebroplasty. Our findings highlight anemia as a risk factor of long-term mortality in this elderly surgical population.

Mapping core characteristics of internet-based tools to maintain and improve population health

 

Rapid developments and implementation of digital technologies in public health domains throughout the last decades have changed the landscape of health delivery and disease prevention globally. Many countries introduce digital interventions to their health systems to improve their populations’ health and make access to health care more accessible. Despite multiple definitions for digital public health and the development of different digital interventions, no study has analysed whether the used technologies fit the definition and the core characteristics of digital public health interventions. Digital public health for us means using digital tools to achieve public health goals. We conducted a scoping review to map the characteristics of digital public health interventions, see how the understanding of specific interventions differs between countries, and how they fit in the theoretical framework of digital public health definitions. Our review is the first to display the landscape of worldwide existing digital public health interventions that use information- and communication technologies. The study’s protocol was published in March 2022 in JMIR Research Protocols (DOI 10.2196/33404). We searched five databases (PubMed, Web of Science, CENTRAL, Ieee, and ACM) for publications. Given the broad search string, we retrieved 13,869 results screened for eligibility. A total of 1,429 publications were included for full-text screening. The study showed that the terms for specific interventions are related to the context in which they are used. Scandinavian countries displayed a different understanding of electronic health records (EHRs) than South American countries. We also identified that the separation between digital health and digital public health is blurry in praxis. Although interventions such as EHRs target individuals to improve their health, the collected data can also be pooled to allow research and the development of interventions on a public health level.

Key messages

• When comparing interventions internationally, it’s best to compare based on the characteristics of the intervention rather than on the name.

• Although, in theory, the distinguishment between digital health, digital public health, and public health became more precise in recent years, the practical reality between them remains still blurry.

Biomechanical effects of different numbers and locations of screw-in clavicle hook plates

Purpose: We sought to analyze the biomechanical effects which both different numbers and locations of screws have on three different clavicle hook plates, as well as any possible causes of sub-acromial bone erosion and peri-implant clavicular fractures.

Methods: This study built thirteen groups of finite element models using three different clavicle hook plates (short plates, long plates, and posterior hook offset plates) in varying numbers and locations of the screws. The von Mises stress distribution of the clavicle and hook plate, as well as the reaction force of the acromion was evaluated.

Results: The results show that inserting screws in all available screw holes on the hook plate produces a relatively large reaction force on the acromion, particularly in the axial direction of the bone plate. The fewer the screws implanted into the clavicle hook plate, the larger the area of high-stress distribution there is in the middle of the clavicle, and also, the higher the stress distribution on the clavicle hook plate.

Conclusion: This study provides orthopedic physicians with the biomechanical analysis of different numbers and locations of screws in clavicle hook plates to help minimize surgical complications.

Robot-Assisted Pedicle Screw Placement Led to Lower Screw Loosening Rate than Fluoroscopy-Guided Technique in Transforaminal Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Single-Center Retrospective Study

Robot-assisted pedicle screw placement for spine surgery has become popular in recent years. This study compares clinical, radiographic outcomes and the screw loosening rate between robot-assisted and fluoroscopy-guided pedicle screw placement in patients who underwent transforaminal lumbar interbody fusion (TLIF). We retrospectively examined 108 patients with the degenerative lumbar disease who underwent TLIF. According to whether the robotic system was used, patients were assigned to either the robot-assisted (Ro TLIF, n = 29) or fluoroscopy-guided TLIF (FG TLIF, n = 79) group. Radiographic parameters and patient-reported outcomes, including leg and back pain visual analog scale (VAS) and Oswestry Disability Index (ODI), were assessed. Loosening signs were noted in 48 out of 552 pedicle screws. The screw loosening rate was higher in the FG TLIF (10.2%) than Ro TLIF group (4.3%). A significant correlation was found between screw loosening and age, the number of level(s) fused, and the ratio of the average distance from the pedicle screw to the upper endplate to vertebral body height. VAS-leg, VAS-back, and ODI showed significant improvements in both groups postoperatively (all p < 0.05). These results indicated that robot-assisted pedicle screw placement in TLIF had a lower screw loosening rate and similar patient-reported outcomes compared with the fluoroscopy-guided technique.

Indirect decompression via oblique lumbar interbody fusion is sufficient for treatment of lumbar foraminal stenosis

Oblique lumbar interbody fusion (OLIF) is a popular technique for the treatment of degenerative lumbar spinal disease. There are no clear guidelines on whether direct posterior decompression (PD) is necessary after OLIF. The purpose of this study was to analyze the effect of the indirect decompression obtained from OLIF in patients with lumbar foraminal stenosis. We retrospectively reviewed 33 patients who underwent OLIF surgery for degenerative lumbar spinal disease between 1 January 2018, and 30 June 2019. The inclusion criteria included patients who were diagnosed with lumbar foraminal stenosis by preoperative MRI. The exclusion criteria included the presence of central canal stenosis, spinal infection, vertebral fractures, and spinal malignancies. The clinical results, evaluated using the visual analogue scale of back pain (VAS-Back), VAS of leg pain (VAS-Leg), and Oswestry disability index (ODI), were recorded. The radiologic parameters were also measured. The VAS-Back, VAS-Leg, and ODI showed significant improvement in both the PD and non-posterior decompression (Non-PD) groups postoperatively (all, p < 0.05). Patients in the Non-PD group showed better results than those in the PD group in the VAS-Back at 12- and 24 months postoperatively (0.00 vs. 3.00 postoperatively at 12 months, p = 0.030; 0.00 vs. 4.00 postoperatively at 24 months, p = 0.009). In addition, the ODI at 24 months postoperatively showed better improvement in the Non-PD group (8.89 vs. 24.44, p = 0.038). The disc height in both the PD and the Non-PD groups increased significantly postoperatively (all, p < 0.05), but the restoration of foraminal height was significantly different only in the Non-PD group. There was no statistically significant difference in cage position, cage subsidence, fusion grade, or screw loosening between the PD and the Non-PD groups. Indirect decompression via OLIF for lumbar foraminal stenosis showed favorable outcomes. The use of interbody cages and posterior instrumentation was sufficient for relieving symptoms in patients with lumbar foraminal stenosis. Additional direct posterior decompression may deteriorate results in the follow-up period.

The Impact of COVID-19 Surges in 2019–2021 on Patient-Reported Outcome Measures After Spine Surgery at an Academic Tertiary Referral Center in Taiwan: A Retrospective Observational Cohort Study

Aim

Limited data are available on the impact of the coronavirus disease 2019 (COVID-19) pandemic on patient-reported outcome measures (PROMs) in patients who underwent spine surgery. In this study, we aimed to investigate the associations between the COVID-19 outbreak in Taiwan (May 2021) and PROMs in patients who underwent spine surgery.

Method

We retrospectively identified patients who underwent spine surgery during identical defined 6-week time-intervals (May 16 to June 30) in 2019, 2020, and 2021. PROMs, including visual analog scale (VAS) score for pain, Oswestry disability index (ODI), and EuroQol-5D (EQ-5D), were investigated before surgical intervention and at a 1-month follow-up. Relevant clinical information was collected from the electronic medical records of patients. Linear regression analysis was used to examine the association between the pandemic in 2021 (vs. 2019/2020) and the PROMs after adjusting for age, sex, and relevant clinical variables.

Results

The number of patients who underwent spine surgery at our hospital during the identical defined 6-week time-intervals in 2019, 2020, and 2021 was 77, 70, and 48, respectively. The surgical intervention significantly improved VAS, ODI, and EQ-5D of the patients (1 month after surgery vs. before surgery, all p < 0.001) in all three study periods. However, there was a significant between-group difference in change from baseline in VAS (p = 0.002) and EQ-5D (p = 0.010). The decrease in VAS and increase in EQ-5D after surgery in 2021 were not as much as those in 2019 and 2020. The associations between the pandemic in 2021 (vs. 2019/2020) and changes in VAS (β coefficient 1.239; 95% confidence interval [CI] 0.355 to 2.124; p = 0.006) and EQ-5D (β coefficient, −0.095; 95% CI, −0.155 to −0.035; p = 0.002) after spine surgery were independent of relevant clinical factors.

Conclusion

There was less improvement in short-term PROMs (VAS and EQ-5D) after spine surgery during the COVID-19 pandemic. Assessment of PROMs in surgical patients during a pandemic may be clinically relevant, and psychological support in this condition might help improve patients' outcomes.

The Morphological Changes in Adjacent Segments Amongst Patients Receiving Anterior and Oblique Lumbar Interbody Fusion: A Retrospective Study

Adjacent segment disease (ASD) is troublesome condition that has proved to be highly related to spinal malalignment after spinal surgery. Hence, we aimed to evaluate the morphological changes after anterior lumbar interbody fusion (ALIF) and oblique LIF (OLIF) to establish the differences between the two surgical methods in terms of possible ASD avoidance. Fifty patients, half of whom received ALIF while the other half received OLIF, were analyzed with image studies and functional outcomes during the pre-operative and post-operative periods, and 2 years after surgery. Image measurements obtained included spinal-pelvic parameters, index lordosis (IL), segmental lordosis (SL), anterior disc height (ADH), posterior disc height (PDH) and adjacent segment disc angle (ASDA). The ADH and PDH in the adjacent segment decreased in the two groups while OLIF showed greater decrease without radiological ASD noted at 2-year follow-up. Both groups showed an increase in IL after surgery while ALIF showed greater improvement. No statistical difference was identified in functional outcomes between LIFs. We suggest that both ALIF and OLIF can restore adequate lordosis and prevent ASD after surgery. However, it should be noted that patient selection remains crucial when making any decision involving which of the two methods to use.

Paradoxical spinopelvic motion: does global balance influence spinopelvic motion in total hip arthroplasty?

Background

Recent research has proposed a classification of spinopelvic stiffness according to pelvic spatial orientation for risk stratification in patients who undergo total hip arthroplasty (THA). However, the influence of global alignment was not investigated, and this study evaluated the effect of global balance (sagittal vertical axis [SVA]) on spinopelvic motion.

Methods

We conducted a retrospective review of consecutive primary THA patients. We measured SVA, spinopelvic parameters (pelvic tilt [PT], pelvic incidence, and sacral slope), thoracic kyphosis (TK), lumbar lordosis (LL), proximal femur angle (PFA), and cup version using functional radiographs of patients in the standing and upright sitting positions. Linear regression was performed to identify parameters related to global trunk alignment change (∆SVA). Spinopelvic stiffness was defined as PT position change < 10°, and a subset of patients with PT change < 0° was categorized into a paradoxical spinopelvic motion group.

Results

One hundred twenty-four patients were analyzed (mean age: 65 years, 61% female). In univariate regression analysis, ∆TK, ∆LL, and ∆PFA were correlated to ∆SVA. In multivariate regression analysis, ΔLL (p < 0.001) and ΔPFA (p < 0.001) were found to be correlated to ΔSVA (ΔSVA = − 11.97 + 0.05ΔTK – 0.23ΔLL – 0.17ΔPFA; adjusted R² = 0.558). Spinopelvic stiffness was observed in 40 patients (32%), including five (4%) with paradoxical motion (∆PT = − 3° ± 1°, p < 0.001) with characteristics of balanced standing global trunk alignment (standing SVA = − 1.0 ± 5.1 cm), similar stiffness of the lumbosacral spine (∆LL = − 7° ± 5°), higher hip motion (∆PFA = − 78° ± 6°, p = 0.017), and higher anterior trunk shift (∆SVA = 6.2 ± 2.0 cm, p = 0.003) from standing to sitting as compared to the stiffness group. Two of these five patients experienced dislocation events after THA.

Conclusions

The lumbosacral and hip motions were the major contributors to global alignment postural change. Paradoxical motion is a rare but dangerous clinical condition in THA that might be related to a disproportionally large trunk shift in the stiff lumbosacral spine causing excessive hip motion. In paradoxical motion, diminishing functional acetabular clearance during position change might pose the prosthesis at higher risk of impingement and instability than spinopelvic stiffness.

Correlation between Preoperative Serum Levels of Calcium, Phosphate, and Intact Parathyroid Hormone and Radiological Outcomes in Spinal Interbody Fusion among End-Stage Renal Disease Patients

Spinal fusion surgery for end-stage renal disease (ESRD) patients is a clinical challenge. This study aimed to investigate whether postoperative radiological outcomes are related to preoperative serum calcium, phosphate, or intact parathyroid hormone (iPTH) levels in patients with ESRD who underwent spinal interbody fusion surgery. This study included 62-consecutive patients with ESRD who underwent anterior cervical discectomy and fusion (ACDF) or transforaminal lumbar interbody fusion (TLIF) surgery for symptomatic spinal disorder. The most recent preoperative serum calcium, phosphate, and iPTH levels were recorded, and the postoperative radiographic outcomes were assessed. A significant correlation was found between the occurrence of cage subsidence and higher blood phosphate, calcium–phosphate product (Ca × P), and iPTH levels in the TLIF group. The occurrence of pedicle screw loosening was related to higher blood phosphate and Ca × P product in the TLIF group. However, no correlation was found between the fusion grades and the serum levels in either the TLIF or ACDF groups. These results indicated that higher preoperative serum phosphate and Ca × P product are risk factors for both cage subsidence and screw loosening in patients with ESRD who underwent TLIF surgery. Higher iPTH levels are also a possible risk factor for cage subsidence.

Biomechanical analysis of reduction technique for lumbar spondylolisthesis: anterior lever versus posterior lever reduction method

BACKGROUND

Reduction of lumbar spondylolisthesis during spinal fusion surgery is important for improving the fusion rate and restoring the sagittal alignment. Despite the variety of reduction methods, the fundamental mechanics of lumbar spondylolisthesis reduction remain unclear. This study aimed to investigate the biomechanical behavior while performing spondylolisthesis reduction with the anterior and posterior lever reduction method.

METHODS

We developed an L4-L5 spondylolisthesis model using sawbones. Two spine surgeons performed the simulated reduction with a customized Cobb elevator. The following data were collected: the torque and angular motion of Cobb, displacement of vertebral bodies, change of lordotic angle between L4 and L5, total axial force and torque applied on the model, and force received by adjacent disc.

RESULTS

Less torque value (116 N-cm vs. 155 N-cm) and greater angular motion (53o vs. 38o) of Cobb elevator were observed in anterior lever reduction. Moreover, the total axial force received by the entire model was greater in the posterior lever method than that in the anterior lever method (40.8 N vs. 16.38 N). Besides, the displacement of both vertebral bodies was greater in the anterior lever method.

CONCLUSIONS

The anterior lever reduction is a more effort-saving method than the posterior lever reduction method. The existing evidence supports the biomechanical advantage of the anterior reduction method, which might be one of the contributing factors to successfully treating high-grade lumbar spondylolisthesis with short-segment instrumentation.

Biomechanical analysis of the treatment of intertrochanteric hip fracture with different lengths of dynamic hip screw side plates

BACKGROUND

Dynamic hip screw (DHS) is a common implant used to treat stable-type intertrochanteric hip fractures. There are many factors that can affect the success rate of the surgery, including the length of side plates. It is therefore important to investigate the biomechanical effect of different DHS side plates on bones.

OBJECTIVE

In order to reduce the likelihood of an implant failure, the aim of this study was to use finite element analysis (FEA) to investigate and understand the effect of side plates with different lengths in DHS.

METHODS

In this FEA study, a 3D model with cortical bone, cancellous bone, side plate, lag screw, and cortical screws to simulate the implantation of DHS with different lengths of side plate (2-hole, 4-hole, and 6-hole) for intertrochanteric hip fractures was constructed. The loading condition was used to simulate the force (400 N) on the femoral head and the stress distribution on the lag screw, side plate, cortical screws, and femur was measured.

RESULTS

The highest stress points occured around the region of contact between the screw and the cortical bones. The stress on the femur at the most distal cortical screw was the greatest. The shorter the length of the side plate, the greater the stress on the cortical screws, resulting in an increased stress on the femur surrounding the cortical screws.

CONCLUSIONS

The use of DHS with 2-hole side plate may increase the risk of side plate pull-out. The results of this study provide a biomechanical analysis for selection of DHS implant lengths that can be useful for orthopaedic surgeons.

The radiological outcome in lumbar interbody fusion among rheumatoid arthritis patients: a 20-year retrospective study

BACKGROUND

Clinical outcomes amongst Rheumatoid Arthritis (RA) patients have shown satisfactory results being reported after lumbar surgery. The increased adoption of the interbody fusion technique has been due to a high fusion rate and less invasive procedures. However, the radiographic outcome for RA patients after receiving interbody fusion has scarcely been addressed in the available literature.

METHODS

Patients receiving interbody fusion including ALIF, OLIF, and TLIF were examined for implant cage motion and fusion status at two-year follow-up. Parameters for the index correction level including ADH, PDH, WI, SL, FW, and FH were measured and compared at pre-OP, post-OP, and two-year follow-up.

RESULTS

We enrolled 64 RA patients at 104 levels (mean 64.0 years old, 85.9% female) received lumbar interbody fusion. There were substantial improvement in ADH, PDH, WI, SL, FW, and FH after surgery, with both ADH and PDH having significantly dropped at two-year follow up. The OLIF group suffered from a higher subsidence rate with no significant difference in fusion rate when compared to TLIF. The fusion rate and subsidence rate for all RA patients was 90.4 and 28.8%, respectively.

CONCLUSIONS

We revealed the radiographic outcomes of lumbar interbody fusions towards symptomatic lumbar disease in RA patients with good fusion outcome despite the relative high subsidence rate amongst the OLIF group. Those responsible for intra-operative endplate management should be more cautious to avoid post-OP cage subsidence.

Direct reduction of high-grade lumbosacral spondylolisthesis with anterior cantilever technique - surgical technique note and preliminary results

Backgrounds

Surgical reduction for high-grade spondylolisthesis is beneficial for restoring sagittal balance and improving the biomechanical environment for arthrodesis. Compared to posterior total laminectomy and long instrumentation, anterior lumbar inter-body fusion (ALIF) is less invasive and has the biomechanical advantage of restoring the original disk height and increasing lumbar lordosis, thus improving sagittal balance. However, the application of ALIF is still limited in treating low-grade spondylolisthesis. In this study, we developed a new technique termed anterior cantilever procedure to directly reduce the slippage of high-grade lumbosacral spondylolisthesis. The purpose of our study was to investigate the surgical outcomes of the anterior cantilever procedure followed by ALIF and posterior mono-segment instrumented fixation in high-grade spondylolisthesis.

Methods

All patients with high-grade spondylolisthesis who underwent anterior cantilever procedure followed by anterior lumbar inter-body fusion (ALIF) and posterior mono-segment instrumented fixation between November 2006 and July 2017 were enrolled in our study. The slip percentage, Dubousset’s lumbosacral angle, pelvic tilt, sacral slope, pelvic incidence, and sagittal alignment were measured pre-operatively and postoperatively at the last follow-up. Surgery time, blood loss, complications, and hospital stay were also collected and analysed.

Results

A total of 11 consecutive patients with high-grade spondylolisthesis patients were included and analysed. All of the high-grade spondylolisthesis in our series occurred at the L5-S1 level. The median age was 37 years, and the median follow-up duration was 36 months. The average slip reduction was 30% (60 to 30%, P < 0.01), and the average correction of Dubousset’s lumbosacral angle was 13.8° (84.1° to 97.9°, P < 0.01). The median intra-operative blood loss was 300 mL. All patients attained improved sagittal balance after the operation and achieved solid fusion within 9 months after surgery. No incidences of implant failure, permanent neurological deficit, or pseudarthrosis were recorded at the last follow-up.

Conclusions

Anterior cantilever procedure followed by ALIF and posterior mono-segment instrumented fixation is a valid procedure for treating high-grade spondylolisthesis. It achieved a high fusion rate, partially reduced slippage, and significantly improved lumbosacral angle, while minimizing common complications, such as pseudarthrosis, nerve traction injury, excessive soft tissue dissection, and blood loss in posterior reduction procedures. However, posterior instrumentation is still required to the structural stability in the ALIF procedure.

Level of evidence

IV

Novel, safe, and easy spinal osteotomy for regional kyphotic deformities

OBJECTIVE

This study aimed to assess the efficacy and safety of a newly developed transpedicular, anterior open-wedge osteotomy procedure with lamina preservation to correct sagittal imbalance in regional kyphotic deformities following compression fractures.

METHODS

All seven patients [four females and three males; mean (range) age, 67 (56-78) years] included in this study underwent surgery between May 2005 and May 2016 for symptomatic, rigid kyphosis secondary to compression fractures. Transpedicular, anterior open-wedge osteotomy with lamina preservation was performed in all patients using an osteotome to create a transverse fracture in the vertebral body through bilateral pedicles and an anterior open-wedge space filled with compacted bone graft to correct kyphosis. Pre- and post-operative kyphotic Cobb angles were evaluated, and the volume of intra-operative blood loss was measured.

RESULTS

The pre- and post-operative kyphotic Cobb angle was 35.3° and 17.7°, respectively (p<0.01); mean angle correction was 17.6° (p<0.05). No patient developed any complication with neurologic injury. Mean blood loss was 771 mL. Callus formation viewed on plain film was evident in all patients and was accompanied by decreased thoracolumbar back pain.

CONCLUSION

Transpedicular, anterior open-wedge osteotomy with lamina preservation is an easy and safe spinal osteotomy procedure for the correction of regional, fixed kyphotic deformities.

LEVEL OF EVIDENCE

Level IV, Therapeutic study.

[Targeted-knockdown of Yes-associated protein inhibits the Warburg effect and the invasion of laryngeal cancer cells]

Objective: To investigate the migration and invasion behaviors of Hep-2 after the targeted knockdown of yes-associated protein (YAP). Methods: Hep-2 cells were knock-downed for YAP by shRNA as YAP-shRNA group, Hep-2 treated with non-specific shRNA as YAP-NC group, and Hep-2 with no treatment as control. Glucose uptake and lactate production in the cells were examined to assess Warburg effect. The migration and invasion behaviors of cells in three groups were observed. The expressions of vimentin and E-cadherin were detected by RT-PCR and Western Blot. The statistical software GraphPad Prism 7.0 was used to analyze significance of data. Two tailed Student' s t-tests was used to determine significance when only two groups were compared. P values of less than 0.05 was considered statistically significant. Results: Downregulation of YAP led to a obvious decrease in glucose uptake [(18.51±1.72)%] and lactate production [103.40±8.32] in Hep-2 cells compared with control [(41.20±1.11)% and 743.69±19.49, t=19.20 and 52.33, respectively, both P<0.01] and YAP-NC group [(39.60±0.78)% and 705.22±17.20, t=19.34 and 54.56, respectively, both P<0.01]. Compared with the control group (78.32±4.04) and YAP-NC group (77.28±3.11), the scratch healing ability of Hep-2 cells was significantly decreased in YAP-shRNA group (44.71±4.68). The P value was less than 0.01 (t=9.42 and 10.04). The number of cells with YAP-shRNA (33.30±4.19) passing through compartments was remarkable fewer than the control group (133.71±6.72) and YAP-NC group (126.32±4.21). The P value was less than 0.01 (t=21.96 and 27.13). The expression of E-cadherin protein in cells of YAP-shRNA group (6.16±0.11) was up-regulated compared with control (0.97±0.10, t=35.70, P<0.01) and YAP-NC group (1.13±0.09, t=36.28, P<0.01), while the expression of vimentin protein in cells of YAP-shRNA group (1.08±0.09) was down-regulated compared with control (5.67±0.12, t=29.91, P<0.01) and YAP-NC group (5.51±0.12, t=29.04, P<0.01). Conclusions: The down-regulation of YAP in Hep-2 inhibits the migration and invasion of cells via suppressing Warburg and EMT program.

Impact of tip-apex distance and femoral head lag screw position on treatment outcomes of unstable intertrochanteric fractures using cephalomedullary nails

Background

Cephalomedullary nails are frequently used in unstable intertrochanteric fractures. The implant position is an important factor for surgical success. Thus, in the present study, finite element analysis methods were used to investigate the biomechanical behavior of five different cephalomedullary nail positions in unstable intertrochanteric fractures.

Methods

Five different cephalomedullary nail implant positions were investigated. The observed indicators were the maximum displacement of the lag screw, the stress on the intertrochanteric fracture with involvement of the posteromedial cortex, and the tip–apex distance.

Results

The smallest lag screw displacement was achieved when the implant was closer to the inferior femoral head. Lower stress was placed on the posteromedial cortex when the implant was positioned closer to the inferior femoral head. However, the tip–apex distance increased when the lag screw was positioned more inferiorly.

Conclusions

The results of this study suggest that positioning the lag screw closer to the inferior aspect of the femoral head can reduce stress on the posteromedial cortex and deformation of the implant in unstable intertrochanteric fractures. These findings provide a biomechanical basis for selection of the cephalomedullary nail implantation site.

Level of evidence

III.

Spatial geometric and magnetic resonance signal intensity changes with advancing stages of nucleus pulposus degeneration

Background

With advancing stages of degeneration, denaturation and degradation of proteoglycans in the nucleus pulposus (NP) lead to tissue dehydration and signal intensity loss on T2-weighted MR images. Pfirrmann grading is widely used for grading degeneration of intervertebral discs (IVDs). The criterion to differentiate IVDs of Pfirrmann Grade I from the other grades is NP homogeneity. Pfirrmann grading is qualitative and its assessment may be subjective. Therefore, assessment of quantitative objective measures correlating with early disc degeneration may complement the grading. This study aimed to evaluate the applicability of the distance between the center weighted by signal intensity (weighted center) and the geometric center as a parameter of NP homogeneity. Other phenomena related to advancing stages of degeneration were also investigated.

Methods

MR images of 65 asymptomatic volunteers with a total of 288 lumbar IVDs with clearly identifiable nucleus pulposus boundary (Pfirrmann Grade I, II and III) were included in this study. A custom-written program was developed to determine the IVD longitudinal axis, define the NP boundary, and to locate the coordinates of geometric and weighted NP centers on the mid-sagittal image of each studied IVD. The distances between the weighted and geometric centers on the longitudinal axis and the perpendicular axis of each IVD were calculated.

Results

The weighted center located posterior to the geometric center, which indicated the signal intensity was lower at the anterior portion of the NP, in 85.8% of studied IVDs. The distance between the weighted and geometric center on the longitudinal axis was significantly shorter in homogeneous (Pfirrmann Grade I) than in inhomogeneous (Grade II) IVDs. The distance on the perpendicular axis in Grade III IVDs was significantly larger than that in Grade I and Grade II IVDs.

Conclusion

The relationship between the weighted and geometric centers can serve as an indicator for NP homogeneity. The distance between both centers through advancing stages of degeneration demonstrated decrease of signal intensity progressing along the longitudinal axis initially and then along the cranio-caudal direction at later stages. These findings could provide insights of initiation and subsequent progression of degenerative changes in IVDs.

Patients with diabetes in pay-for-performance programs have better physician continuity of care and survival

OBJECTIVES

This study investigated the effects of physician continuity, measured as the Continuity of Care Index (COCI) score, on the survival of patients with diabetes, including both pay-for-performance (P4P) participants and nonparticipants.

STUDY DESIGN

This was a retrospective, nationwide population-based analysis of 396,838 patients with diabetes, with 198,419 subjects each in the P4P participant and nonparticipant groups, from 1997 to 2009, in Taiwan.

METHODS

The data presented in this study are secondary data obtained from the 1997 to 2009 National Health Insurance Research Database published by the Taiwan National Health Research Institute. Survival status and physician continuity were the dependent variables. Multiple regression analysis was used to examine the factors related to physician continuity among patients with diabetes. The Cox proportional hazard model was used to explore the related factors that affected the survival status of the patients with diabetes.

RESULTS

After controlling for the other related factors, the COCI score of the P4P participants was 0.227 higher than that of the nonparticipants (P <.05). Compared with patients with a low COCI score (≤50%), the hazard ratio (HR) of mortality of patients with a high COCI score (>50%) was 0.47 (95% confidence interval [CI], 0.46-0.48). Compared with nonparticipants, the HR of mortality of P4P participants was 0.43 (95% CI, 0.41-0.44).

CONCLUSIONS

Patients with diabetes with higher physician continuity had a lower HR of mortality. P4P participants had higher physician continuity and a lower HR of mortality.

A novel bioprinting method and system for forming hybrid tissue engineering constructs

Three dimensional (3D) bioprinting is a promising approach to form tissue engineering constructs (TECs) via positioning biomaterials, growth factors, and cells with controlled spatial distribution due to its layer-by-layer manufacturing nature. Hybrid TECs composed of relatively rigid porous scaffolds for structural and mechanical integrity and soft hydrogels for cell- and growth factor-loading have a tremendous potential to tissue regeneration under mechanical loading. However, despite excessive progress in the field, the current 3D bioprinting techniques and systems fall short in integration of such soft and rigid multifunctional components. Here we present a novel 3D hybrid bioprinting technology (Hybprinter) and its capability enabling integration of soft and rigid components for TECs. Hybprinter employs digital light processing-based stereolithography (DLP-SLA) and molten material extrusion techniques for soft and rigid materials, respectively. In this study, poly-ethylene glycol diacrylate (PEGDA) and poly-(ε-caprolactone) (PCL) were used as a model material for soft hydrogel and rigid scaffold, respectively. It was shown that geometrical accuracy, swelling ratio and mechanical properties of the hydrogel component can be tailored by DLP-SLA module. We have demonstrated the printability of variety of complex hybrid construct designs using Hybprinter technology and characterized the mechanical properties and functionality of such constructs. The compressive mechanical stiffness of a hybrid construct (90% hydrogel) was significantly higher than hydrogel itself (∼6 MPa versus 100 kPa). In addition, viability of cells incorporated within the bioprinted hybrid constructs was determined approximately 90%. Furthermore, a functionality of a hybrid construct composed of porous scaffold with an embedded hydrogel conduit was characterized for vascularized tissue engineering applications. High material diffusion and high cell viability in about 2.5 mm distance surrounding the conduit indicated that culture media effectively diffused through the conduit and fed the cells. The results suggest that the developed technology is potent to form functional TECs composed of rigid and soft biomaterials.

Biomechanical analysis of acromioclavicular joint dislocation treated with clavicle hook plates in different lengths

PURPOSE

Clavicle hook plates are frequently used in clinical orthopaedics to treat acromioclavicular joint dislocation. However, patients often exhibit acromion osteolysis and per-implant fracture after undergoing hook plate fixation. With the intent of avoiding future complications or fixation failure after clavicle hook plate fixation, we used finite element analysis (FEA) to investigate the biomechanics of clavicle hook plates of different materials and sizes when used in treating acromioclavicular joint dislocation.

METHODS

Using finite element analysis, this study constructed a model comprising four parts: clavicle, acromion, clavicle hook plate and screws, and used the model to simulate implanting different types of clavicle hook plates in patients with acromioclavicular joint dislocation. Then, the biomechanics of stainless steel and titanium alloy clavicle hook plates containing either six or eight screw holes were investigated.

RESULTS

The results indicated that using a longer clavicle hook plate decreased the stress value in the clavicle, and mitigated the force that clavicle hook plates exert on the acromion. Using a clavicle hook plate material characterized by a smaller Young's modulus caused a slight increase in the stress on the clavicle. However, the external force the material imposed on the acromion was less than the force exerted on the clavicle.

CONCLUSIONS

The findings of this study can serve as a reference to help orthopaedic surgeons select clavicle hook plates.

Effects of multidisciplinary team care on the survival of patients with different stages of non-small cell lung cancer: a national cohort study

In Taiwan, cancer is the top cause of death, and the mortality rate of lung cancer is the highest of all cancers. Some studies have demonstrated that multidisciplinary team (MDT) care can improve survival rates of non-small cell lung cancer (NSCLC) patients. However, no study has discussed the effect of MDT care on different stages of NSCLC. The target population for this study consisted of patients with NSCLC newly diagnosed in the 2005–2010 Cancer Registry. The data was linked with the 2002–2011 National Health Insurance Research Database and the 2005–2011 Cause of Death Statistics Database. The multivariate Cox proportional hazards model was used to explore whether the involvement of MDT care had an effect on survival. This study applied the propensity score as a control variable to reduce selection bias between patients with and without involvement of MDT care. The adjusted hazard ratio (HR) of death of MDT participants with stage III & IV NSCLC was significantly lower than that of MDT non-participants (adjusted HR = 0.87, 95% confidence interval = 0.84-0.90). This study revealed that MDT care are significantly associated with higher survival rate of patients with stage III and IV NSCLC, and thus MDT care should be used in the treatment of these patients.

Displacement of the distal radioulnar joint of clinically symptom-free patients

There are three methods for evaluation of dislocation of the distal radioulnar joint using computed tomography: the radioulnar line method, the epicenter method, and the congruity method. However, some patients who are clinically symptom-free have abnormal findings from computed tomography of the distal radioulnar joint according to the aforementioned criteria. In addition, these methods are qualitative, not quantitative definitions. Forty patients were included in this study. Computed tomography scans of the wrists were done. The variation of displacement of the distal radioulnar joint was measured. By the epicenter method, the 95% confidence interval (mean +/- 1.96 standard error) was from 0.0026 to 0.1114 in supination and from -0.1171 to 0.0446 in pronation. By the radioulnar line method, the 95% confidence interval was from 0.0026 to 0.0479 in supination and from -0.0065 to 0.0745 in pronation. By the modified radioulnar line method, the 95% confidence interval was from 0.1778 to 0.2752 in supination and from 0.0990 to 0.2310 in pronation. There was a wide range of the displacement of the distal radioulnar joint in patients with clinically normal wrists. The results can be regarded as reference points for normal variation of the distal radioulnar joint. This can help to differentiate the causes of internal derangement of the wrist.

Influence of 3D-CRT pelvic irradiation on outcome in prostate cancer treated with external beam radiotherapy

PURPOSE

The role of pelvic irradiation (PRT) in the treatment of prostate cancer remains unclear. We reviewed our institution's experience with three-dimensional conformal external beam radiotherapy (3D-CRT) during the prostate-specific antigen era to determine the influence of PRT on the risk of biochemical recurrence in patients who have a predicted risk of lymph node involvement.

METHODS AND MATERIALS

Between March 1985 and January 2001, 1832 patients with clinically localized prostate cancer were treated with definitive 3D-CRT. All treatments involved CT planning to ensure coverage of the intended targets. Treatment consisted of prostate-only treatment, prostate and seminal vesicle treatment, or PRT of lymph nodes at risk followed by a boost. To create relatively homogenous analysis groups, each patient's percentage of risk of lymph node (%rLN) involvement was assigned by matching the patient's T stage, Gleason score, and initial prostate-specific antigen level to the appropriate value as described in the updated Partin tables. Three categories of %rLN involvement were defined: low, 0-5%; intermediate, >5-15%; and high, >15%. Biochemical recurrence was defined as the first occurrence of either the American Society for Therapeutic Radiology and Oncology consensus definition of prostate-specific antigen failure or the initiation of salvage hormonal therapy for any reason.

RESULTS

The risk status (%rLN) could be determined for 709 low-risk, 263 intermediate-risk, and 309 high-risk patients. The actuarial freedom from biochemical recurrence (bNED) and the log-rank test for the similarity of the control and treatment survival functions are reported for each risk group. Multivariate analysis demonstrated a statistically significant benefit for the entire population treated with PRT, with a relative risk reduction of 0.72 (95% confidence interval 0.54-0.97). Although the multivariate analysis could not determine the patient population that would most benefit from PRT, the beneficial effect appeared to be most pronounced within the intermediate-risk group. Univariate analysis revealed that the intermediate-risk patients treated with PRT had an improved 2-year bNED rate, 90.1% vs. 80.6% (p = 0.02), and both low-risk and high-risk patients treated with PRT had statistically similar 2-year bNED rates compared with those who did not receive it.

CONCLUSION

Pelvic 3D-CRT appears to improve bNED in prostate cancer patients. Additional studies are needed to elucidate the %rLN population for which this treatment should be recommended.

Thymoma is associated with an increased risk of second malignancy

BACKGROUND

An association between thymoma and second malignancy has been suggested but has not been validated. Whether the relation is due to treatment or to other thymoma-associated conditions is unclear.

METHODS

The authors studied 192 consecutive patients with thymoma and compared the incidence of second malignancies with those of 206 patients who underwent thymectomy for nonthymomatous conditions and 1426 patients with nasopharyngeal carcinoma (NPC). Detailed clinicopathologic features of thymoma patients with second malignancies were described.

RESULTS

Additional malignancies were detected in 15 of 192 patients (8%) during their clinical courses. The risk for those patients was significantly greater compared with the risk for patients with nonthymomatous conditions (adjusted odds ratio [OR], 3.81; 95% confidential intervals [95%CI], 1.05-13.81; P = 0.042) and patients with NPC (adjusted OR, 4.89; 95%CI, 2.26-10.53; P < 0.0001) after adjustment for age, gender, length of follow-up, myasthenia gravis, and radiation therapy. The occurrence of second malignancies did not correlate with histologic type or stage of thymoma, radiation therapy, or myasthenia gravis.

CONCLUSIONS

Thymoma is associated with an increased risk of second malignancy. The association cannot be attributed to the effect of thymectomy or radiation therapy. Patients with thymoma, even if it is benign, should be followed regularly to facilitate the early detection of other malignancies.

High failure rate using allograft fascia lata in pubovaginal sling surgery for female stress urinary incontinence

OBJECTIVES

To present our unfavorable experiences using allograft fascia lata. Allograft fascia lata is an attractive sling material providing less pain, a shorter operation time, and a reported effectiveness equal to autologous fascia.

METHODS

A total of 18 women (mean age 51.7 years, range 37 to 76) underwent pubovaginal sling surgery for stress urinary incontinence between March 1999 and July 1999 and were enrolled in this study. Solvent dehydrated gamma-irradiated human fascia lata with a size of 7 x 2 cm was used as the sling. The results were collected with a questionnaire survey.

RESULTS

All patients were followed up for a mean of 9.2 months (range 6.9 to 11.6). Thirteen patients considered the surgery successful or to have provided improvement, with a mean of 82.5% (range 50% to 100%) subjective improvement. Five patients (27.8%) had significant failure with full recurrence of incontinence within 3 to 6 months.

CONCLUSIONS

Solvent dehydrated gamma-irradiated allograft fascia is not reliable in pubovaginal sling surgery. The high failure rates within a short period prohibit its use in the operative management of stress urinary incontinence.

Thymoma is associated with an increased risk of second malignancy

BACKGROUND

An association between thymoma and second malignancy has been suggested but has not been validated. Whether the relation is due to treatment or to other thymoma-associated conditions is unclear.

METHODS

The authors studied 192 consecutive patients with thymoma and compared the incidence of second malignancies with those of 206 patients who underwent thymectomy for nonthymomatous conditions and 1426 patients with nasopharyngeal carcinoma (NPC). Detailed clinicopathologic features of thymoma patients with second malignancies were described.

RESULTS

Additional malignancies were detected in 15 of 192 patients (8%) during their clinical courses. The risk for those patients was significantly greater compared with the risk for patients with nonthymomatous conditions (adjusted odds ratio [OR], 3.81; 95% confidential intervals [95%CI], 1.05-13.81; P = 0.042) and patients with NPC (adjusted OR, 4.89; 95%CI, 2.26-10.53; P < 0.0001) after adjustment for age, gender, length of follow-up, myasthenia gravis, and radiation therapy. The occurrence of second malignancies did not correlate with histologic type or stage of thymoma, radiation therapy, or myasthenia gravis.

CONCLUSIONS

Thymoma is associated with an increased risk of second malignancy. The association cannot be attributed to the effect of thymectomy or radiation therapy. Patients with thymoma, even if it is benign, should be followed regularly to facilitate the early detection of other malignancies.

Comparative analysis of sampling methods for grossing radical prostatectomy specimens performed for nonpalpable (stage T1c) prostatic adenocarcinoma

Scant data are available comparing sampling methods of radical prostatectomy specimens performed for clinical stage T1c (nonpalpable) cancer. Seventy-eight stage T1c radical prostatectomies that had 1 or more of the following adverse pathologic findings-Gleason score > or = 7, positive margins, and extraprostatic extension-were compared using 10 different sampling techniques. Of the 78 entirely submitted cases, 52 had Gleason score > or = 7, 14 had positive margins, and 54 had extraprostatic extension (mean 34 slides). Of the partial sampling methods, we favor the following two methods. The first is submitting every posterior section plus 1 midanterior section from right and left sides; if either of these anterior sections show sizeable tumor, all ipsilateral anterior slides are examined. This method detects 98% of tumors with Gleason score > or = 7, 100% of positive margins, and 96% of cases with extraprostatic extension (mean 27 slides). The second method is to use the above method but restrict it to sections ipsilateral to the previous positive needle biopsy. This method detects 92% of tumors with Gleason score > or = 7, 93% of positive margins, and 85% of cases with extraprostatic extension (mean 17 slides). Partial sampling can detect important prognostic parameters. By balancing the extra expense and time involved to process and examine additional sections with the risk of missing important prognostic parameters, pathologists can decide which sampling method to use.

Real-time dynamic telepathology through the Internet: evaluation of a new and economic technology at Taipei Veterans General Hospital

BACKGROUND

Computer-aided, digitalized telepathology was introduced about 10 years ago and is gaining acceptance as a mode of providing pathology to remote site. The usefulness of telepathology for remote diagnosis of histology, cytology and frozen section has been evaluated in USA, Europe and Japan. In Taiwan, the use of telepathology for pathological diagnosis is still rare. In order to evaluate the potential use of this technique, we undertook the study using commercialized and low-cost microscopy, personal computer and software on routine biopsy material.

METHODS

Sixty prostatic sextant transrectal needle biopsies, including 30 cases of adenocarcinoma and 30 cases of benign lesions, were retrieved retrospectively. The real-time dynamic images were transmitted to the remote site via internet and reviewed by a senior uropathologist who was unaware of the diagnosis. The diagnoses made at the remote site were correlated to the final diagnoses of the cases.

RESULTS

All malignant specimens (30/30) were correctly diagnosed by this method. Only one benign case (1/31) of nonspecific granulomatous prostatitis was misdiagnosed as poorly differentiated carcinoma.

CONCLUSIONS

Our results show that this method is a good way for teleconsultation. Further studies on other types of specimen worth encouragement for both intra- and inter-institutional consultation.

Expression of cyclooxygenase-2 in prostate adenocarcinoma and benign prostatic hyperplasia

Elevated expression of cyclo-oxygenase (COX)-2 has been found in several human cancers, including prostate adenocarcinoma. To evaluate the potential prognostic role of COX-2 in prostate cancer, we assessed the expression of COX-2 in benign prostatic hyperplasia (BPH) and prostate cancer samples employing immunohistochemistry. COX-2 was over-expressed in 15 out of 18 (83%) prostate cancer samples whereas it was detected in only 22% (4 of 18) paired benign tissues. The intensity of immunostaining correlated with the tumor grading. In addition, COX-2 was expressed in 7 of the 22 (32%) BPH samples examined. The significance a COX-2 expression in the BPH samples is not known at present. This data suggest that COX-2 is over-expressed in prostate cancer and COX-2 inhibitors may be useful in combination chemotherapy or chemoprevention for prostate cancer.

Spindle cell and mixed spindle/lymphocytic thymomas: an integrated clinicopathologic and immunohistochemical study of 81 cases

Forty-three cases of spindle cell thymoma (medullary, WHO type A) and 38 cases of mixed spindle/lymphocytic thymoma (WHO type AB) were studied for their clinicopathologic and immunohistochemical characteristics. Three histologic patterns of spindle cell thymoma were observed: short-spindled (57%), long-spindled (31%), and micronodular (12%). The short-spindled variant was composed of oval to short spindle cells commonly arranged in a hemangiopericytic or microcystic pattern. The long-spindled variant chiefly consisted of fibroblast-like epithelial cells mimicking fibrohistiocytic neoplasms. The micronodular variant was characterized by small nests of short spindle cells dispersed among a lymphoid stroma with frequent germinal centers. All kinds of spindle cell could be admixed with lymphocyte-rich "cortex"-like areas to constitute mixed spindle/lymphocytic thymomas. Immunohistochemically, the epithelial cells in up to 70% of the short-spindled and long-spindled variants of spindle cell thymoma and 90% of mixed spindle/lymphocytic thymomas were positive for CD20, whereas the epithelial cells in all micronodular spindle cell thymomas were negative. All of the spindle cell thymomas and most of the mixed spindle/lymphocytic thymomas in this study were found in stages I and II. Follow up of the patients did not disclose relapse or mortality directly resulting from the tumors. However, the prognosis of stage I and II spindle cell and mixed spindle/lymphocytic thymomas did not significantly differ from those of stage I and II thymomas of other types by a stage-matched survival analysis. Our data showed that spindle cell and mixed spindle/lymphocytic thymomas are distinctive in histologic pattern and immunohistochemical profile. When interpreted within the context of staging, spindle cell and mixed spindle/lymphocytic thymomas presenting in stages I and II most likely behave in an indolent fashion.

Tubulocystic clear cell adenocarcinoma arising within the prostate

Neoplasms resembling ovarian common epithelial-type tumors, including clear cell adenocarcinomas, rarely occur in the lower urinary tract of men. When they do, they develop in the urethra or urinary bladder. We report a case of such a tumor arising within the prostate of a 47-year-old man. The tumor was a cystic mass in the left posterolateral region of the prostate. Histologically, the tumor was chiefly composed of tubulocystic and papillary glands lined by glycogen-rich, cuboidal or hobnail cells with clear to eosinophilic cytoplasm. The tumor cells were strongly positive for pan-cytokeratin, low molecular weight cytokeratin, and epithelial membrane antigen, and focally positive for high molecular weight keratin. The tumor did not immunohistochemically express prostate-specific antigen (PSA) and prostatic acid phosphatase. Serologically, the patient had increased levels of CA125 instead of PSA. The clinical as well as the pathologic features are consistent with a clear cell adenocarcinoma as seen in the female genital tract rather than a typical prostatic adenocarcinoma.

The prognostic significance of tertiary Gleason patterns of higher grade in radical prostatectomy specimens: a proposal to modify the Gleason grading system

The Gleason grading system of prostatic adenocarcinoma does not account for the existence of a tertiary (third most prevalent) pattern, and there are no studies concerning the latter's prognostic influence. The authors analyzed 114 radical prostatectomies with small tertiary components, which mostly occupied less than 5% of whole tumors. These specimens were compared with a prostatectomy database comprised of 2,276 cases without a tertiary component. The pathologic stages of "typical" Gleason score 5 to 6 tumors (Gleason scores 2 + 3 = 5, 3 + 2 = 5, 3 + 3 = 6), which contained tertiary patterns 4 or 5, were significantly higher than those of "typical" Gleason score 5 to 6 tumors without pattern 4 (p = 0.018) but lower than those of "typical" Gleason score 7 tumors (p = 0.021; Gleason scores, 3 + 4 = 7, 4 + 3 = 7). Typical Gleason score 7 tumors with a tertiary pattern 5 showed significantly worse pathologic stages than typical Gleason score 7 tumors (p = 0.008) without pattern 5 and were not different statistically from typical Gleason score 8 (Gleason score, 4 + 4 = 8) tumors. Both typical Gleason score 5 to 6 and 7 tumors with tertiary components revealed significantly higher progression rates than typical Gleason score 5 to 6 tumors (p <0.0001) and Gleason score 7 tumors (p = 0.003) without tertiary components, and progressed like typical Gleason score 7 and 8 tumors respectively. Tertiary high-grade components have an adverse impact on biologic behavior. The authors propose that the Gleason system for radical prostatectomy specimens be modified to take into account small volumes of patterns 4 and 5, which are important prognostically.

Transitional cell carcinoma in dialysis patients

OBJECTIVE

The aim of our study was to determine whether there is an increased incidence of urothelial cancer, especially transitional cell carcinoma (TCC), in uremic patients on dialysis.

METHODS

Retrospective chart analyses were completed for 1,910 uremic patients undergoing maintenance dialysis between January 1987 and December 1997. The incidence of urinary tract cancer was assessed. Only the patients with cancers diagnosed after start of dialysis were enrolled in the study.

RESULTS

Of the 1,910 patients, 70 had concomitant urinary tract cancers. Nineteen patients (0.99%), including 17 patients with TCC and 2 patients with renal cell carcinoma, were diagnosed after the initiation of dialysis. The average duration from dialysis to TCC diagnosis was 38.3 (range 2-144) months. Painless gross hematuria was the cardinal symptom in 16 of the 17 patients with TCC. In the 17 patients with TCC, no distant metastases were found at the time of diagnosis. Fourteen patients (82.3%) were stage 0 or A, and 1 patient was stage B1.

CONCLUSIONS

The 0.89% incidence of TCC in our dialysis patients was high as compared with that of the general population. The risks of developing urinary TCC in dialysis patients were examined, and we suggest that immunosuppressive stage, dialysis procedure, and chronic bladder irritation (decreased urinary wash effect) may play a part in the development of urinary TCC in dialysis patients. Early detection of hematuria due to regular visits and decreased exposure of urinary tract epithelium to carcinogens from urine may explain why early-stage TCC was seen in most of our patients.

Evaluation and validation of ureteric jet index by glomerular filtration rate

RATIONALE AND OBJECTIVES

Ureteric jet index (UJI), a newly developed technique derived from color Doppler ultrasonography, may hold promise in evaluating renal function because of its ability to evaluate individual renal function and the use of nonionizing radiation. To assess the usefulness of UJI, the authors in this study analyzed the relation between UJI and the glomerular filtration rate (GFR).

METHODS

Fifteen adult patients with a wide range of renal function were included in this study. Subjects were well hydrated before color Doppler ultrasonography examinations. The UJI formula was: Vmean (average jet velocity) x D (jet duration) x F (jet frequency). GFR was calculated by the radionuclide method. Correlations between UJI, serum creatinine, and GFR were analyzed.

RESULTS

Ureteric jet index had only a fair correlation with GFR. The coefficient of correlation value was 0.61, and the standard error of estimate of GFR was 17.9 mL/min.

CONCLUSIONS

With the measurement of UJI, color Doppler ultrasound can provide both structural images and individual renal function information. It could substitute for a renal scan in determining individual renal function when a radionuclide examination is unavailable. Even if a renal scan were available, UJI can play a valuable role in the ultrasound examination of patients with suspected impaired renal function, providing further assessment of individual renal function.

Argyrophilic nucleolar organizer regions in cells of thymoma and thymic carcinoma: correlation with DNA ploidy and clinicopathologic characteristics

STUDY OBJECTIVES

To evaluate the usefulness of argyrophilic nucleolar organizer region (AgNOR) counting and flow cytometric DNA analysis in the differential diagnosis of thymoma and thymic carcinoma, as well as in the differences among various stages and histologic subtypes of these tumors.

DESIGN AND INTERVENTIONS

Paraffin-embedded blocks of 64 thymic epithelial tumors (20 noninvasive thymomas, 34 invasive thymomas, and 10 thymic carcinomas) were studied by AgNOR counting and flow cytometric DNA analysis. The thymomas were histologically classified as medullary, cortical, or mixed subtype.

MEASUREMENTS AND RESULTS

Invasive thymomas had more AgNORs (-/+ SD) than noninvasive thymomas (7.93+/-2.90 vs 5.97+/-1.77; p < 0.01). The number of AgNORs of thymoma increased progressively with advances in stage (p < 0.01). Cortical thymomas had the highest number of AgNORs among the three subtypes (p < 0.05). Patients with thymoma who presented with myasthenia gravis also had a higher number of AgNORs (8.30+/-3.12 vs 6.50+/-2.03; p < 0.01). The AgNOR number did not correlate with the DNA ploidy of all specimens.

CONCLUSIONS

AgNOR counting is useful in differentiating between invasive and noninvasive thymomas, and in predicting the stage of thymomas. A greater number of AgNORs was observed in patients with cortical thymoma and in those who presented with myasthenia gravis.

Iron-deficient diet reduces atherosclerotic lesions in apoE-deficient mice

BACKGROUND

Iron deposition is evident in human atherosclerotic lesions, suggesting that iron may play a role in the development of atherosclerosis. To test this idea, the correlation between the extent of iron deposition and the severity of atherosclerosis in apolipoprotein E (apoE)-deficient mice was investigated. Furthermore, the effect of a low-iron diet on the progression of atherosclerotic lesions in these animals was evaluated.

METHODS AND RESULTS

Iron deposition in tissues of apoE-deficient mice was examined by Perls' staining method. The results clearly demonstrated that iron deposits are present in atherosclerotic lesions and tissue sections of heart and liver in an age-dependent manner. When the young mice received a low-iron diet for 3 months, the hematocrit, serum iron, hemoglobin, and cholesterol concentrations were not significantly altered compared with those of littermates placed on a chow diet. However, the serum ferritin level of animals in the iron-restricted group was 27% to 30% lower than that of the control group in either sex. Furthermore, the lipoproteins isolated from the iron-restricted group exhibited greater resistance to copper-induced oxidation. Histological examination revealed that atherosclerotic lesions developed in mice fed a low-iron diet were significantly smaller than those found in control littermates. Likewise, the iron deposition as well as tissue iron content was much less in aortic tissues of the iron-restricted animals. Circulating autoantibodies to oxidized LDL and immunostains for epitopes of malondialdehyde-modified LDL detected on lesions were also significantly lower in mice fed a low-iron diet.

CONCLUSIONS

Iron deposition is closely associated with the progression of atherosclerosis in apoE-deficient mice. Restriction in dietary iron intake leads to significant inhibition of lesion formation in these animals. These results suggest that the beneficial effect of a low-iron diet may be mediated, at least in part, by the reduction of iron deposition as well as LDL oxidation in vascular lesions.

The role of interleukin 12 in the development of atherosclerosis in ApoE-deficient mice

The cytokine profile of atherosclerotic aortas from apoE-deficient mice was assessed by reverse transcriptase-polymerase chain reaction. The results clearly showed that the expression of mRNA for IL-12p40 was evident in aortas from 3-month-old apoE-deficient mice. The mRNA for IL-10 was detected in aorta from these mice at the age of 6 months, indicating that expression of IL-12 is earlier than that of IL-10 in these animals. Concurrent with IL-12p40, the mRNA for the T-cell cytokine IFN-gamma, but not IL-4, was detected in aortas of mice at young and old ages. Both in situ hybridization and immunostaining further demonstrated the localization of IL-12 in macrophages of atherosclerotic lesions. Immunohistochemistry also demonstrated the expression of costimulatory molecules B7-1 and B7-2 in macrophages, suggesting that activation of T lymphocytes by macrophages may occur via surface antigens in lesions. When the immunoglobulin isotype of the antioxidized LDL antibodies in sera of apoE-deficient mice was determined, it revealed that both IgM and IgG were present. Furthermore, IgG2a is predominant and comprises approximately 50% of the antioxidized LDL IgG in sera from young mice (3 months), but decreased to lower levels (35%) in older mice (6 months). Daily administration of IL-12 led to an increase in serum levels of antioxidized LDL antibodies and accelerated atherosclerosis in young apoE-deficient mice compared with control mice injected with PBS alone. Taken together, these data suggest that IL-12 plays an active role in regulating the immune response during the early phase of atherosclerosis in apoE-deficient mice.

Ki67 labelling index correlates with stage and histology but not significantly with prognosis in thymoma

AIMS

There have been several cell kinetic studies of thymoma, but the effectiveness of using Ki67 antibody as a tool to measure proliferative activity in this tumour was rarely evaluated. We carried out an immuno-histochemical study using this antibody to assess the clinicopathological correlation and the prognostic significance of this technique.

METHODS AND RESULTS

Ninety-one cases of thymoma were collected. Double immunostaining with Ki67 and cytokeratin KL-1 antibodies was performed on paraffin sections. Ki67 labelling index (LI) was expressed as a percentage of Ki67 immunopositive nuclei by counting at least 1000 epithelial cells. The LIs were correlated with stages, histological subtypes based on both Lattes-Bernatz and Müller-Hermelink-Kirchner classifications, and length of survival. There were statistically significant differences of LIs between stage I and stage III and between stage I and stage IV tumours. Histologically, statistically significant differences were identified between predominantly epithelial thymoma and every other subtype of the Lattes-Bernatz classification and between well-differentiated thymic carcinoma and medullary or mixed thymomas of the Müller-Hermelink-Kirchner classification. Regarding the prognostic implication of Ki67 LI, although there appeared a trend that patients with tumours of higher LIs had slightly worse survival, the difference was not statistically significant in both univariate and multivariate survival analyses.

CONCLUSIONS

We have demonstrated the proliferative potential in thymoma is associated with stage and histology. However, its clinical usefulness is limited on account of the overlap of LIs and lack of prognostic significance.

Colocalization of iron and ceroid in human atherosclerotic lesions

The presence of ceroid, a complex of protein associated with oxidized lipids, is commonly observed in human atherosclerotic lesions. When the human aortic walls were examined by Perls' staining, it was found that the iron deposits were evident in aortas with atherosclerosis. The extent of iron deposition was associated with the severity of the lesion. Furthermore, the iron deposits appeared to be colocalized with ceroids either extracellularly or intracellularly in foam cell-like macrophages or smooth muscle cells. Electron microscopy and X-ray microanalysis revealed that some of the extracellular iron aggregates were present within the ceroids. Likewise, some of the subcellular iron aggregates were found to be located near the lipid droplets or within the ceroids of foam cells. Collectively, these observations support the theory that the lipid oxidation occurring in lipid-laden cells of aortic lesions is facilitated by iron-overload in these cells.

Expression of E-cadherin and alpha- and beta-catenins in thymoma

Expression of the cell adhesion molecules including E-cadherin and its cytosolic binding proteins, alpha- and beta-catenins, has been widely studied in a variety of tumours, but not, to date, in thymic epithelial tumours. To observe the expression pattern of these adhesion molecules, immunohistochemical stains for E-cadherin (E-CD) and alpha- and beta-catenins were performed on 89 cases of thymoma which were classified as cortical (57 cases), mixed (18 cases), and medullary (14 cases), based on the classification of Marino and Müller-Hermelink. The majority of cortical thymomas showed diffuse and homogenous membrane immunoreactivity for these molecules (88 per cent for E-CD; 86 per cent for alpha-catenin; 91 per cent for beta-catenin) and the remaining cases showed heterogeneous immunoreactivity, whereas almost all mixed and medullary thymomas revealed decreased expression or were negative. In each histological subtype of thymoma, the expression did not correlate with invasion or with the presence of myasthenia gravis. These results indicate that the expression of E-CD and alpha- and beta-catenins is more closely associated with the histological subtypes of thymoma than with their biological behaviour.

Lower gastrointestinal bleeding from a hepatocellular carcinoma invading the colon

Bleeding from the gastrointestinal tract due to hepatocellular carcinoma invasion is unusual. We describe a 71-year-old man who had bloody stools caused by a hepatocellular carcinoma that directly invaded the transverse colon. The diagnosis was confirmed by colonoscopy and tissue examination. Our patient is the first with lower gastrointestinal bleeding from a hepatocellular carcinoma during the natural course of the tumor.

Signet-ring cell carcinoma of the rectum with tonsillar metastasis: a case report

A 36-year-old man was diagnosed as a case of mucinous adenocarcinoma of the rectum, Dukes' C. Pathologic examination revealed abundant signet-ring cells in the tumor. He did not receive adjuvant radiotherapy or chemotherapy after resection of the tumor. Two years later, a 3 x 5 cm mass over the right palatine tonsil was found with associated right neck lymphadenopathy. Right tonsillectomy was performed. Metastatic mucinous adenocarcinoma of the tonsil with abundant signet-ring cells similar to the primary tumor of the rectum was found. Signet-ring cell carcinoma of the rectum with tonsillar metastasis is extremely rare. No case has been reported in the English literature. To the best of our knowledge, this is the first case of signet-ring cell carcinoma of the rectum with tonsillar metastasis. The relevant literature on metastatic tonsillar tumors is reviewed.