Carl P.C. Chen

Ultrasound guidance in caudal epidural needle placement.

Background:This study was conducted to investigate the feasibility of using ultrasound as an image tool to locate the sacral hiatus accurately for caudal epidural injections. Methods:Between August 2002 and July 2003, 70 patients (39 male and 31 female patients) with low back pain and sciatica were studied. Soft tissue ultrasonography was performed to locate the sacral hiatus. A 21-gauge caudal epidural needle was inserted and guided by ultrasound to the sacral hiatus and into the caudal epidural space. Proper needle placement was confirmed by fluoroscopy. Results:In all the recruited patients, the sacral hiatus was located accurately by ultrasound, and the caudal epidural needle was guided successfully to the sacral hiatus and into the caudal epidural space. There was 100% accuracy in caudal epidural needle placement into the caudal epidural space under ultrasound guidance as confirmed by contrast dye fluoroscopy. Conclusions:Ultrasound is radiation free, is easy to use, and can provide real-time images in guiding the caudal epidural needle into the caudal epidural space. Ultrasound may therefore be used as an adjuvant tool in caudal needle placement.

Ultrasound-guided shoulder injections in the treatment of subacromial bursitis.

Chen MJL, Lew HL, Hsu TC, Tsai WC, Lin WC, Tang SFT, Lee YC, Hsu RCH, Chen CPC: Ultrasound-guided shoulder injections in the treatment of subacromial bursitis. Am J Phys Med Rehabil 2006;85:31–35. Objective:To investigate the treatment effectiveness between ultrasound-guided and blind injection techniques in the treatment of subacromial bursitis. Design:A total of 40 patients with sonographic confirmation of subacromial bursitis were recruited into this study. These patients were divided into blind and ultrasound-guided injection groups. The shoulder abduction range of motion was compared before injections and 1 wk after the completion of injections in both groups. Results:The shoulder abduction range of motion before injection in the blind injection group was 71.03 ± 12.38 degrees and improved to 100 ± 18.18 degrees 1 wk after the injection treatments. However, the improvement did not reveal significant statistical differences (P > 0.05). The shoulder abduction range of motion before injection in the ultrasound-guided injection group was 69.05 ± 14.72 degrees and improved to 139.29 ± 20.14 degrees 1 wk after the injection treatments (P < 0.05). Conclusions:Ultrasound may be used as an adjuvant tool in guiding the needle accurately into the inflamed subacromial bursa. The ultrasound-guided injection technique can result in significant improvement in shoulder abduction range of motion as compared with the blind injection technique in treating patients with subacromial bursitis.

Sagittal plane loading response during gait in different age groups and in people with knee osteoarthritis.

Chen CPC, Chen MJL, Pei YC, Lew HL, Wong PY, Tang SFT: Sagittal plane loading response during gait in different age groups and in people with knee osteoarthritis. Am J Phys Med Rehabil 2003;82:307–312. Objective To investigate the gait patterns and the sagittal ground reaction forces in different age groups and in people with knee osteoarthritis. Design Motion analysis and force platform data were collected for a total of 55 female subjects capable of independent ambulation. Subjects were divided into three groups consisting of the control group, the elderly group, and the osteoarthritis knee group. Gait parameters of walking velocity, cadence, step length, stride time, single- and double-support time, and sagittal ground reaction forces were obtained during comfortable walking speed. Gait analysis was performed in a tertiary hospital’s gait laboratory. Variables were analyzed using a univariate repeated-measures analysis of variance. Statistical significance was set at a value of P < 0.05. Results The osteoarthritis knee group had slower walking velocity, lower cadence, and longer stride time as compared with the elderly and young control groups (P < 0.05). In ground reaction force studies, the first peak time, expressed in percentage of gait cycle, was significantly longer in the osteoarthritis knee group (20.8 ± 3.2) as compared with the elderly (17.8 ± 2.0) and young control groups (17.1 ± 1.8, P < 0.01). The force during time of minimal midstance was larger in the osteoarthritis knee group (90.9 ± 5.3) as compared with the elderly and young control groups (P < 0.05). The second peak force was significantly smaller in the osteoarthritis knee group as compared with the young control group (P < 0.01). The force change in the midfoot region in the osteoarthritis knee and elderly groups revealed more loading force onto the midfoot region during midstance as compared with the young control group (P < 0.01). Conclusion Gait parameters in the elderly and osteoarthritis knee patients were characterized by slower walking velocity, lower cadence, shorter step length, longer stride time, and longer double-support time. Less heel contact and push-off forces were noticed in these two groups, with more loading force onto the midfoot during midstance.

Introduction to musculoskeletal diagnostic ultrasound: examination of the upper limb.

Lew HL, Chen CPC, Wang T-G, Chew KTL: Introduction to musculoskeletal diagnostic ultrasound: examination of the upper limb. Am J Phys Med Rehabil 2007;86:310–321. With recent advances in computer technology and equipment miniaturization, the clinical application of diagnostic ultrasonography (U/S) has spread across various medical specialties. Diagnostic U/S is attractive in terms of its noninvasiveness, lack of radiation, readiness of use, cost-effectiveness, and its ability to make dynamic examinations possible. Dynamic imaging deserves special emphasis because it is useful in differentiating full-thickness from partial-thickness tendon tears, muscle tears, and tendon and nerve subluxations or dislocations. It is also a quick and easy avenue for side-to-side comparisons. When appropriately used, diagnostic U/S can be considered as an extension of ones physical examination. However, there are limitations of U/S, which will be discussed in this review article. This is part 1 of two articles; this first part will focus on the ultrasound examination of the upper extremity, using selected examples relevant to musculoskeletal medicine. Part 2 will cover common pathologies of the lower extremity.

Measurement of forefoot varus angle by laser technology in people with flexible flatfoot.

Chen MJL, Chen CPC, Lew HL, Hsieh WC, Yang WP, Tang SFT: Measurement of forefoot varus angle by laser technology in people with flexible flatfoot. Am J Phys Med Rehabil 2003;82:842–846. Objective The purpose of this study was to measure the forefoot varus angles in subjects with and without flexible flatfoot (FF) by using laser foot-scanning technology. Design In the rehabilitation laboratory of a tertiary medical center, 70 subjects with FF, ranging in age from 10 to 50 yr, were recruited. The control group consisted of 30 volunteers without clinical evidence of FF. A total of 100 positive casts were obtained by having their subtalar joints kept in a neutral position. The plantar surface of the positive cast was scanned by a Yeti 3D Foot Scanner. A straight line was drawn between the first and fifth metatarsophalangeal joints. The forefoot varus angle was measured from this line in relation to the line parallel to the ground. Results The mean forefoot varus angle was calculated to be 5.01 ± 4.51 degrees in our FF subjects, and 1.23 ± 1.96 degrees in the control group. Significant statistical difference in forefoot varus angle was noted between these two groups. Conclusions The laser foot-scanning technique offers fast and accurate measurement of the forefoot varus angles. An average forefoot varus angle of approximately 5 degrees was observed in subjects with FF, which was significantly greater than the subjects without FF. Therefore, we recommend the concept of incorporating adequate forefoot posting at the medial forefoot area of an insole in treating people with FF.

Ciprofloxacin up-regulates tendon cells to express matrix metalloproteinase-2 with degradation of type I collagen

Ciprofloxacin‐induced tendinopathy and tendon rupture have been previously described, principally affecting the Achilles tendon. This study was designed to investigate the effect of ciprofloxacin on expressions of matrix metalloproteinases (MMP)‐2 and ‐9, tissue inhibitors of metalloproteinase (TIMP)‐1 and ‐2 as well as type I collagen in tendon cells. Tendon cells intrinsic to rat Achilles tendon were treated with ciprofloxacin and then underwent MTT (tetrazolium) assay. Real‐time reverse‐transcription polymerase chain reaction (RT‐PCR) and Western blot analysis were used, respectively, to evaluate the gene and protein expressions of type I collagen, and MMP‐2. Gelatin zymography was used to evaluate the enzymatic activities of MMP‐2 and ‐9. Reverse zymography was used to evaluate TIMP‐1 and ‐2. Immunohistochemical staining for MMP‐2 in ciprofloxacin‐treated tendon explants was performed. Collagen degradation was evaluated by incubation of conditioned medium with collagen. The results revealed that ciprofloxacin up‐regulated the expression of MMP‐2 in tendon cells at the mRNA and protein levels. Immunohistochemistry also confirmed the increased expressions of MMP‐2 in ciprofloxacin‐treated tendon explants. The enzymatic activity of MMP‐2 was up‐regulated whereas that of MMP‐9, TIMP‐1 or TIMP‐2 was unchanged. The amount of secreted type I collagen in the conditioned medium decreased and type I collagen was degraded after ciprofloxacin treatment. In conclusion, ciprofloxacin up‐regulates the expressions of MMP‐2 in tendon cells and thus degraded type I collagen. These findings suggest a possible mechanism of ciprofloxacin‐associated tendinopathy.

The influence of ageing in the cerebrospinal fluid concentrations of proteins that are derived from the choroid plexus, brain, and plasma.

Studies have shown that ageing alone can cause increases in the concentrations of many cerebrospinal fluid (CSF) proteins. Therefore, CSF protein concentrations must be interpreted with caution before concluding that the increased concentrations of certain proteins can be used as disease-specific biomarkers. Age-related reduction in CSF turnover has been shown to have a significant concentrating effect on CSF proteins from young to old. As a result, CSF protein concentrations need to be corrected with age-specific turnovers first before performing any data comparisons between different ages. This study applied the concept of CSF/plasma concentration ratios of plasma-derived proteins that is frequently used in the investigation of brain barrier integrity to calculate the amount of protein that enters the CSF from the plasma side in different age groups. Based on our calculations, proteins with molecular weights greater than 91.92 kDa for the young, 109.51 kDa for the middle-aged and 120 kDa for the old should not be able to cross the brain barriers of the blood-brain and blood-CSF barriers to enter the CSF from the plasma side. For proteins that can be derived from the choroid plexus (CP), brain, and plasma, the amount that crosses the barriers to enter the CSF from the plasma side will contribute to their measured total protein concentrations in the CSF. CP and brain production of these proteins can be calculated when turnover corrected CSF protein concentrations are further corrected by the amount of protein that crosses the barriers. In this study, CP and brain produced concentrations of transthyretin, retinol binding protein, alpha-1-antitrypsin, gelsolin, and lactotransferrin were calculated. The production of these proteins decreased with age with alpha-1-antitrypsin protein revealing the most substantial decrease of 86% from young (0.14±0.01 mg·dL(-1)) to old (0.02 mg·dL(-1)). In conclusion, measured CSF protein concentrations for proteins that can be derived from the CP, brain, and plasma need to be corrected by age-specific CSF turnovers and by the amount of protein that crosses the brain barriers first before their concentrations can be compared logically between different ages.

Changes in windlass effect in response to different shoe and insole designs during walking

Windlass effect occurs during the pre-swing phase of gait cycle in which the peak tensile strain and force of the plantar aponeurosis (PA) is reached. The increased dorsiflexion angle of the 1st metatarsophalangeal (MTP) joint is the main causing factor. The aim of this study was to investigate thoroughly in finding the appropriate shoe and insole combination that can effectively decrease the windlass effect. Foot kinematic analyses of 10 normal volunteers (aged 25.2±2.1 years, height of 167.4±9.1 cm, and weight of 66.2±18.1 kg) were performed during gait under the conditions of barefoot, standard shoe (SS) with flat insole (FI) or carbon fiber insole (CFI), and rocker sole shoe (RSS) with FI or CFI. The shoe cover consisting of transparent polymer was used for accurate measurement of kinematic data as specific areas on the cover can be cut away for direct placement of reflective markers onto the skin. Under barefoot condition, the mean of maximum dorsiflexion angle of the 1st MTP joint was measured to be 48.0±7.3°, and decreased significantly to 28.2±5.7° when wearing SS with FI, and 24.1±5.7° when wearing SS with CFI. This angle was further decreased to around 13° when wearing RSS with FI or CFI. Subjects wearing footwear alone can increase the minimum medial longitudinal angle and decrease the maximum plantarflexion angle of metatarsus related to the calcaneus as compared with barefoot condition, resulting in flatter medial foot arch. Results suggested that RSS is the effective footwear in reducing the windlass effect regardless the type of insole inserted. The findings in this study provided us with the evidences in finding the appropriate footwear for treating foot disorders such as plantar fasciitis by effectively reducing the windlass effect.

Age-related changes in choroid plexus and blood–cerebrospinal fluid barrier function in the sheep

Dysfunction of the choroid plexuses (CPs) and the blood-cerebrospinal fluid barrier (BCSFB) might contribute to age-related cognitive decline and neurodegenerative disease. We used the CPs from young (1-2 years), middle-aged (3-6 years) and old (7-10 years) sheep to explore effects of aging on various aspects of CP and BCSFB functions. Total protein in the cerebrospinal fluid (CSF) was significantly higher in old compared to young sheep and CSF secretion by the CP perfused in situ was significantly lower in both old and middle-aged when compared to young sheep, which correlated with reduced (22)Na(+) uptake and efflux by the CP. Steady-state extractions of a low and medium size molecular weight extracellular space marker, (14)C-mannitol and (3)H-polyethylene glycol, respectively, were significantly higher in CPs from old compared to young animals; however, there was no significant difference in steady-state extraction of a high molecular weight marker, (125)I-bovine serum albumin. This indicates increased passive BCSFB permeability for small and medium sized molecules in old sheep. CP redox activity was significantly lower in the old animals as assessed by the MTT assay, however, there was no significant difference in ATP content and energy charge of the CP with age suggesting adequate baseline energy reserve capacity. These data indicate that normal aging processes alter protein content in the CSF, CSF secretion, integrity of the BCSFB and Na(+) flux in the epithelial layer, which could impact on CSF homeostasis and turnover.

The effect of aging on migration, proliferation, and collagen expression of tenocytes in response to ciprofloxacin.

Quinolone‐induced tendinopathy or tendon rupture tends to be age‐related. However, the synergistic effects of quinolone and aging on tenocytes remained to be explored. Tenocytes intrinsic to rat Achilles tendon from two age groups (young: 2 months; and near senescent (old): 24 months) were treated with ciprofloxacin. Tenocyte migration and proliferation were assessed by transwell filter migration assay and MTT (3‐[4,5‐Dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide) assay, respectively. Messenger RNA and protein expressions of types I and III collagen were determined by reverse transcription‐polymerase chain reaction (RT/PCR) and Western blot analysis, respectively. Transwell filter migration assay revealed that ciprofloxacin inhibited tenocytes migration, which became more significant in old tenocytes (p < 0.05). The results of MTT assay revealed that tenocytes proliferation decreased after ciprofloxacin treatment (p < 0.05), which also became more significant in old tenocytes. The results of RT‐PCR and Western blot analysis revealed that mRNA and protein expressions of type I collagen remained unchanged in either young or old tenocytes with ciprofloxacin treatment, whereas the expressions of type III collagen were down‐regulated by ciprofloxacin, which was more significant in old tenocytes. In conclusion, aging potentiated the ciprofloxacin‐mediated inhibition of migration, proliferation, and expression of type III collagen of tenocytes.