Adsorption dialysis: from physical principles to clinical applications.

The uremic syndrome is characterized by the retention of various solutes that would normally be excreted by the kidneys. The substances that interact negatively with biologic functions are called uremic toxins. Over the past five decades, the membranes used for the treatment of chronic kidney disease have continuously evolved. The exposure of blood to any extracorporeal artificial surface results in the activation of several pathways within the body, including those involving coagulation and complement activation. One of the by-products of this generalized activation process is protein adsorption to the membrane surface, another phenomenon which can have a significant impact on solute removal. In fact, an array of studies showed that with increasing size of middle-sized proteins and other compounds, relatively more clearance is achieved by membrane adsorption compared with loss into the dialysate. A high adsorptive capacity, one of the main features of polymethylmethacrylate (PMMA) membranes, is very helpful and may both increase the total amount of solutes removed and remove different kinds of solutes. In this setting, a few studies have shown a variety of efficient clinical implications for adsorption hemodialysis, such as uremic pruritus, anemia, carpal tunnel syndrome and renal amyloidosis, immune dysfunction and improved response to vaccination. In addition, nutrition and survival were also improved using PMMA membranes.

Carpal tunnel syndrome - an occupational hazard facing dentistry.

BACKGROUND: The authors wished to evaluate the comprehensive literature on carpal tunnel syndrome to discover work specific to carpal tunnel syndrome among dentists in order to determine whether there is any correlation with dentists having a higher prevalence of its occurrence. METHODS: A review of dental literature involving carpal tunnel syndrome was undertaken. Details appearing in the literature before 1995 was reviewed in a comprehensive manner and the literature after 1995 were reviewed electronically. RESULTS: The prevalence of carpal tunnel syndrome is higher in dental professionals involved in various aspects of dental specialties. CONCLUSIONS: Abnormal postures, including muscle imbalances, muscle necrosis, trigger points, hypomobile joints, nerve compression and spinal disk herniation or degeneration may result in serious detrimental physiological changes in the body. These changes often result in pain, injury or possible neuroskeletal disorders. CLINICAL IMPLICATIONS: Dentists have an increased risk of carpal tunnel syndrome and precautions and care should be exercised to prevent detrimental irreversible changes occurring.

Does the presence of the palmaris longus tendon influence median nerve function?

INTRODUCTION: The objective of this study was to determine if the presence or absence of a palmaris longis tendon influenced the function of the median nerve across the wrist. The primary hypothesis was that the presence of a palmaris longus tendon would be associated with more median nerve entrapment at the wrist. METHODS: This was a cross-sectional study. Subjects were recruited at a screening of dental professionals. The median and ulnar sensory nerve latencies across the wrist (relative prolongation of the median compared with the ulnar) and the presence or absence of the palmaris longus tendon were the primary outcome measures. RESULTS: A total of 462 subjects were recruited into the study of which 16.2% lacked a palmaris longus tendon. There was no difference in the median nerve function or the percentage with a 0.5 ms prolongation of the median sensory latency when comparing subjects with and without a palmaris longus tendon. CONCLUSIONS: The presence of a palmaris longus tendon does not influence the median nerve function across the wrist.

Evaluation of occupational and non-occupational risk factors associated with carpal tunnel syndrome in dentists.

BACKGROUND: Musculoskeletal disorders are very prevalent among dentists. Of these disorders, carpal tunnel syndrome (CTS) is notable. OBJECTIVE: The aim of this study was to investigate the relationship between the occupational and non-occupational risk factors and CTS among dentists. METHODS: It is a cross-sectional study. We evaluated 106 dentists from dental schools in Tehran. We collected data by a general questionnaire, a hand diagram, and physical examination. A nerve conduction velocity (NCV) test was used to confirm the diagnosis of CTS. The analysis was performed using an independent T-test and logistic regressions on SPSS software. RESULTS: The prevalence of CTS among dentists was 17.9%. Significant risk factors of CTS included: vibration exposure greater than two hours per day (OR: 2.5), a wrist diameter ratio of greater than 0.7 (OR: 10.14), and female sex (OR: 13.38). CONCLUSIONS: Exposure to the hand-arm vibration should be considered as an occupational risk factor for CTS in dentists. Female dentists should take more preventive measures.

Physical ergonomic risk factors of carpal tunnel syndrome among rubber tappers.

This study evaluated physical ergonomic risk factors associated with carpal tunnel syndrome (CTS) among rubber tappers in Thailand. The Boston Carpal Tunnel Syndrome Questionnaire and Phalen's test and Tinel's sign were used to identify 133 cases with CTS and 401 non-CTS controls. Video recordings and Rapid Upper Limb Assessment used to evaluate the level of ergonomic risk in right and left hand postures. Significant physical ergonomic risk factors of CTS were higher number of trees tapped at or below knee level and collecting latex. Among right-handed tappers, tapping at higher than chest level involved significantly higher proportion of right wrist flexion and/or extension, and left wrist radial and/or ulnar deviation and twist than tapping at a lower level.

Revision Total Wrist Arthroplasty Due to Polyethylene Wear, Metallosis-Induced Carpal Tunnel Syndrome, Distal Ulnar Impingement, and Fourth Carpometacarpal Joint Pain: Case Report and Pitfalls to Avoid.

Background: Total wrist arthroplasty (TWA) is indicated to alleviate pain secondary to arthritis while preserving wrist motion. Despite vigilant measures, TWAs are susceptible to complications. The current case illustrates an array of preventable complications which are addressed through operative technique in a revision setting. Case presentation: The patient was a 72-year-old man who presented with chronic pain at the fourth carpometacarpal joint (CMCJ) and distal radioulnar joint with paresthesias in the median nerve distribution. Surgery was undertaken to address the following complications secondary to a previous TWA: impingement of the native distal ulna on the prosthesis, carpal tunnel due to metallosis and polyethylene synovitis, loose carpal component, and prominent screw at the fourth CMCJ. Surgical correction included open carpal tunnel release with extensive flexor tenosynovectomy, distal ulna resection and implant arthroplasty with shortening, revision of carpal component with bone grafting, and shortening of the ulnar screw to avoid crossing the fourth CMCJ. Within 6 months of the procedure, the patient reported resolution of neuropathic symptoms and pain-free motion of the wrist. Discussion: Preventable complications associated with TWA are individually highlighted. In addition, we compare and contrast our approach and surgical technique to current reported literature. Overall, we provide education and guidance to avoid possible TWA pitfalls. Conclusion: With this case report, we hope to increase TWA knowledge with emphasis on the requirements of judicious patient selection, preoperative planning, meticulous surgical technique, and complication awareness for subsequent optimization of wrist function, stability, and durability.

Systemic Amyloidosis Caused by Monoclonal Immunoglobulins: Soft Tissue and Vascular Involvement.

Clinical features of soft tissue amyloid light-chain (AL) amyloidosis include macroglossia, arthropathy, muscle pseudohypertrophy, skin plaques, and carpal tunnel syndrome. Vascular manifestations of AL amyloid include periorbital ecchymosis, jaw or limb claudication, and even myocardial infarction caused by occlusion of small vessel coronary arteries. Some of these features, such as macroglossia, periorbital ecchymosis, and the so-called shoulder-pad sign, are pathognomonic for AL amyloidosis. These findings may be the initial presenting features of the disease, and the recognition of these red flag symptoms is very important for the diagnosis and early intervention on the underlying plasma cell disease.

Syndromes from segmental vibration and nerve entrapment: observations on case definitions for carpal tunnel syndrome.

OBJECTIVES: The purpose of this paper is to assess the overlap and stability of two different case definitions of carpal tunnel syndrome CTS. The analysis considers the association between different case definitions and objective tests (sensory nerve conduction velocities, SNCVs and vibrotactile perception thresholds, TTS), and the natural history of CTS, in the context of two vibration-exposed cohorts. METHODS: Clinical CTS cases were defined in two ways: (1) by the study physician using fixed criteria, and; (2) by questionnaire and hand diagram. SNCV in median and ulnar nerves was measured for digital, transpalmar, and transcarpal segments, and conventionally as from wrist-digit. Skin temperature was assessed as a point measurement by thermistor and regionally by thermal imaging. VTTs were determined at the bilateral fingertips of the third and fifth digits using a tactometer meeting the requirements of ISO 13091-1 (ISO 2001). The subjects were cohorts of shipyard workers in 2001 and 2004, and dental hygienists in 2002 and 2004. RESULTS: Results are reported for 214 shipyard workers in 2001 and 135 in 2004, and for 94 dental hygienists in 2002 and 66 in 2004. In 2001, 50% of shipyard workers were diagnosed as CTS cases by at least one of the diagnostic schemes, but only 20% were positive by both criteria. Among study physician diagnosed cases, 64% were CTS negative in 2001, 76% were negative in 2004, 13% were positive in both years, 22% became negative after being positive, and 11% became positive after being negative. For only study physician diagnosed CTS did VTTs differ between cases differ and non-cases in digit 3; there was no such distinction in digit 5. The dental hygienists had little CTS. CONCLUSION: Clinical case definitions of CTS based on diagrams and self-assessment, and clinical evaluation have limited overlap. Combining clinical criteria to create a more narrow or specific case definition of CTS does not appear to predict SNCV. The natural history of CTS suggests a protean disorder with considerable flux in case status over time.

A self-report joint damage and musculoskeletal disorders data among dentists: a cross-sectional study.

BACKGROUND: Musculoskeletal disorders (MSD) are an occupational health problem that demands a high cost and may also reduce the quality of life and productivity of the dentists. The aim of this study was to evaluate the prevalence of MSD and its association with self-reported joint damage in dentists from São Paulo (Brazil). METHODS: This was a cross-sectional study performed from two self-administered questionnaires - the Nordic Musculoskeletal Questionnaire and the other containing demographic and occupational data - in 6072 dentists. Between April and May 2014, 5885 questionnaires were distributed via e-mail through São Paulo Regional Board of Dentistry (CRO-SP) and 187 in Congress and public offices. Multivariable logistic regression was used to assess the association between explanatory variables (sex, age, level of education, duration of practice in years, number of patients seen per day, previous receipt of information about ergonomics, physical activity, and the presence of joint damage) and MSD. RESULTS: Two hundred eighty-six valid questionnaires were returned. The prevalence of MSD was 63.6% (N.=182). Multivariable logistic regression showed that only the factor of self-reported joint damage has a significant association with MSD (OR 0.001; 95% CI: 0.000-0.007). Concerning the self-reported joint damage (60.1%), the carpal tunnel syndrome was the most frequent (13.2%). CONCLUSIONS: The prevalence of MSD in dentists from São Paulo is high, and carpal tunnel syndrome is the most common self-reported joint damage.

Is beta2-microglobulin-related amyloidosis of hemodialysis patients a multifactorial disease? A new pathogenetic approach.

PURPOSE: Beta2-microglobulin amyloidosis (Abeta(2)M) is one of the main long-term complications of dialysis treatment. The incidence and the onset of Abeta(2)M has been related to membrane composition and/or dialysis technique, with non-homogeneous results. This study was carried out to detect: i) the incidence of bone cysts and CTS from Abeta(2)M; ii) the difference in Abeta(2)M onset between cellulosic and synthetic membranes; iii) other risk factors besides the membrane. METHODS: 480 HD patients were selected between 1986 to 2005 and grouped according to the 4 types of membranes used (cellulose, synthetically modified cellulose, synthetic low-flux, synthetic high-flux). The patients were analyzed before and after 1995, when the reverse osmosis treatment for dialysis water was started at our center, and the incidence of Abeta(2)M was compared between the two periods. Routine plain radiography, computer tomography (CT) and nuclear magnetic resonance imaging (MRI) as well as electromyography were used to investigate the clinical symptoms. RESULTS: Bone cysts occurred in 29.2% of patients before 1995 vs. 12.2% after 1995 (p<0.0001). CTS occurred in 24% of patients before 1995 vs. 7.1% after 1995 (p<0.0001). Bone cysts and CTS occurred in older patients, who began dialysis at a late age, with high CRP, low albumin, low residual GFR, and low Hb. Cox regression analysis showed that the risk factor for bone cysts was high CRP (RR 1.3, p<0.01), while albumin (RR 0.14, p<0.0001) and residual GFR (RR 0.81, p<0.0001) were revealed to be protective factors. Cox analysis for CTS confirmed CRP as a risk factor (RR 1.2, p<0.01), and albumin (RR 0.59, p<0.0001) and residual GFR (RR 0.75, p<0.0001) as protective factors. The comparison obtained between membranes did not suggest any protective effect on Abeta(2)M. CONCLUSIONS: The findings that the inflammatory status as well as low albumin and the residual GFR of the uremic patient are predictive of Abeta(2)M lesions suggests that Abeta(2)M has a multifactorial origin rather than being solely a membrane- or technique-related side effect.

Jaw claudication in primary systemic amyloidosis.

Amyloid deposits in the temporal artery were observed 40 years ago, but the presence of vascular ischemic symptoms in patients with amyloidosis has been infrequently recognized. We examined 22 patients who had typical jaw claudication with biopsy-proven primary amyloidosis. In none was vasculitis a contributing cause of the claudication. However, two patients were misdiagnosed initially as having temporal arteritis and polymyalgia rheumatica and were treated with corticosteroids, which resulted in significant toxicity. Subsequent temporal artery biopsy revealed extensive amyloid deposits in both patients. Jaw claudication was associated with other ischemic vascular symptoms, such as arm or calf claudication. The median survival for the subset of patients with amyloidosis and jaw claudication was 42 months, and that for the entire group of patients with amyloidosis was 12 months. Appropriate staining of temporal artery biopsy specimens is necessary for the correct diagnosis in such cases.

Mucolipidosis III (pseudo-Hurler polydystrophy); clinical studies in aged patients in one family.

Three adult patients (38-year-old male, 86-year-old female, and 61-year-old male) in a family with mucolipidosis III (ML-III) were described. They had characteristic features of ML-III and they survived a long time. N-acetylglucosaminyl 1-phosphotransferase activity was low in fibroblasts of a patient, but its residual activity remained at a relatively high level (24.5-35.3% of controls), which may explain the benign clinical course. Odontoid dysplasia and atlanto-axial dislocation was found in one patient, and surgical treatment improved his physical disability. Bilateral carpal tunnel syndrome as well as claw hand deformities were common in all of the patients. The clinical manifestations were important for the diagnosis and the management of the patients.

Remission of a recurrent carpal tunnel syndrome by a new device of the hemodialysis method in a long-term hemodialysis patient.

This report concerns a case in which remission was achieved from the recurrent carpal tunnel syndrome employing new methods of hemodialysis. These being the maintenance of low endotoxin in dialysate, a highly permeable membrane and a 32-microglobulin-adsorbent column. A 78-year-old female patient with a 19-year history of hemodialysis was diagnosed as being a suitable recipient of a third operation. The concentration of endotoxin was maintained at under 10 EU/l and the highly permeable dialyzer with a larger sieving coefficient of beta2-microglobulin was introduced. A Lixelle adsorption column for beta2-microglobulin removal was also introduced and the serum concentration of the beta-microglobulin was maintained at under 20 mg/dl. Consequently, within 6 months the symptoms in the right hand had completely disappeared, the motor nerve latency had almost normalized at 5.0 msec and no recurrence was observed.

Finger receptor dysfunction in dental technicians exposed to high-frequency vibration.

The effects of high-frequency vibration (up to 40 kHz) on digital nerve function were studied in ten dental technicians and ten age-matched referents. Nerve conduction velocities, including fractionated antidromic measurements over the carpal tunnel, showed no difference between the groups. In the group of dental technicians the difference between the response latency of the mechanical and electric stimuli in the median nerve distally on the fingers of the right hand was slightly higher than in the reference group, and therefore distal nerve or receptor dysfunction was suggested. Vibration warming and cooling thresholds were significantly increased and thus revealed damage to both myelinated and unmyelinated fibers in the fingers of subjects exposed to high-frequency vibration.

Dentist's hand symptoms and high-frequency vibration.

The paper discusses characteristics of mechanical vibration as well as the mechanisms of vibration syndrome. Analysis of the relationship between the high-frequency vibration and the typical symptoms in the hands of the dentists is presented. Suggestions have been offered on how to limit exposure to vibration in the hands of dentists

Behavior of beta 2-microglobulin (B2-m) serum levels in uremic patients.

This study was performed in 97 hemodialysis patients (85 on HD and 12 on CAPD) to investigate the possible correlation between B2-m and hemodialysis-related amyloidosis syndromes (HRA-S); differences in B2-m and HRA behavior between patients hemodialysed with cellulose and synthetic membranes were also included in the present study. Data indicate that B2-m levels are not correlated with dialysis length or with the type of membrane used for the dialysis. On the contrary, in 16 patients with the Carpal Tunnel Syndrome, a significant correlation was found between the CTS, the dialysis length and the type of membrane (greater incidence with cellulosic membranes).

Long-term comparative evaluation of synthetic and cellulosic membranes in dialysis.

A long-term retrospective evaluation (5 years) compares two groups of RDT patients (group 1 on continuous treatment with cellulosic membranes and group 2 with synthetic membranes) regarding survival, general clinical morbidity, and beta 2M-related morbidity. The results showed no significant long-term differences between the groups either for survival or general morbidity despite some differences in biocompatibility. The higher intradialytic removal of beta 2M by synthetic membranes did not lead to a reduction in either pre-dialysis beta 2M values or beta 2M related morbidity. The higher cost of synthetic over cellulosic membranes and the disappointing of many clinical expectations suggest that the use of such membranes, in association with alternative techniques, should take place only according to certain "elective" indications such as old age, diabetes, vascular instability or intradialytic disequilibrium syndrome.

Dialysis-related amyloidosis.

Dialysis-related amyloidosis (DRA) is a complication of long-term dialysis and can also be seen in patients with chronical renal failure and on continuous ambulatory peritoneal dyalisis. This review focuses on the chemical modifications of beta(2)-microglobulin that lead to the formation and deposition of beta(2)-amyloid fibrils in periarticular and articular sites which ultimately results in the clinical and radiographic characteristics of this devastating disease. Its most common manifestations are carpal tunnel syndrome, shoulder pain and destructive arthropathy. Treatment of DRA has been directed towards achieving normal serum levels of beta(2)M in end stage renal disease (ESRD) patients which usually results in clinical improvement and delay in disease progression. Medical treatment consists of the use of corticosteroids and nonsteroidal anti-inflammatory drugs. Surgical intervention for carpal tunnel syndrome or spinal cord compression can greatly improve quality of life.

Evaluating the fit of ambidextrous and fitted gloves: implications for hand discomfort.

Ambidextrous gloves stretch significantly more and exert greater force than fitted gloves when worn. Over time, this force could contribute to vascular constriction, nerve compression, muscle fatigue and hand pain. This study suggests that research on the effects of glove use by dental care personnel is needed.

Silastic scaphoid implants in osteoarthritis of the radioscaphoid joint.

The long term results of Silastic Scaphoid implants are presented in two groups of patients, with osteoarthritis of the radioscaphoid joint without known history of trauma or established pseudarthrosis of the scaphoid bone. The patients in the former group all became satisfied with the operative result whereas in the latter group only half of the patients were satisfied with the result.