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PubMed2006

Cessation of injection drug use and change in injection frequency: the Chicago Needle Exchange Evaluation Study.

AIMS: To examine the effect of a needle exchange program (NEP) on incidence of injection cessation and change in injection frequency; to explore predictors for injection cessation and change in injection frequency; and to assess whether injection quitters transitioned to non-injected drug use. DESIGN AND SETTING: Between 1997 and 2002, 901 injection drug users (IDUs) were recruited from an NEP program or an area with no NEP in Chicago, Illinois, interviewed for drug use behaviors, tested for HIV and followed for three annual visits. All participants were exposed to prevention services targeting HIV and drug abuse. MEASUREMENTS: Injection cessation was defined as no injection drug use since the last interview, and changes in the number of injections in a typical month were examined. FINDINGS: Sixteen per cent of study participants reported stopping injection for a median duration of 16 months, and most of them also ceased rather than initiated the use of non-injected drugs. Those who continued injecting reduced their injection frequency by 12% per year, on average. Independent predictors of injection cessation were infrequent injection at baseline, younger age and injecting with others. NEP use was not associated with injection cessation and change in injection frequency. CONCLUSION: These results did not support the hypothesis that NEP use influences the frequency of injection over time. One-sixth of IDUs stopped injection for more than 1 year, providing a substantial window for relapse prevention interventions.

Adolescent↗

PubMedDate not supplied

Combination of intraneural injection and high injection pressure leads to fascicular injury and neurologic deficits in dogs.

BACKGROUND: Unintentional intraneural injection of local anesthetics may cause mechanical injury and pressure ischemia of the nerve fascicles. One study in small animals showed that intraneural injection may be associated with higher injection pressures. However, the pressure heralding an intraneural injection and the clinical consequences of such injections remain controversial. Our hypothesis is that an intraneural injection is associated with higher pressures and an increase in the risk of neurologic injury as compared with perineural injection. METHODS: Seven dogs of mixed breed (15-18 kg) were studied. After general endotracheal anesthesia, the sciatic nerves were exposed bilaterally. Under direct microscopic guidance, a 25-gauge needle was placed either perineurally (into the epineurium) or intraneurally (within the perineurium), and 4 mL of lidocaine 2% (1:250,000 epinephrine) was injected by using an automated infusion pump (4 mL/min). Injection pressure data were acquired by using an in-line manometer coupled to a computer via an analog digital conversion board. After injection, the animals were awakened and subjected to serial neurologic examinations. On the 7th day, the dogs were killed, the sciatic nerves were excised, and histologic examination was performed by pathologists blinded to the purpose of the study. RESULTS: Whereas all perineural injections resulted in pressures < or =4 psi, the majority of intraneural injections were associated with high pressures (25-45 psi) at the beginning of the injection. Normal motor function returned 3 hours after all injections associated with low injection pressures (< or =11 psi), whereas persistent motor deficits were observed in all 4 animals having high injection pressures (> or =25 psi). Histologic examination showed destruction of neural architecture and degeneration of axons in all 4 sciatic nerves receiving high-pressure injections. CONCLUSIONS: High injection pressures at the onset of injection may indicate an intraneural needle placement and lead to severe fascicular injury and persistent neurologic deficits. If these results are applicable to clinical practice, avoiding excessive injection pressure during nerve block administration may help to reduce the risk of neurologic injury.

Anesthetics, Local↗

PubMed2004

Intensity of drug injection as a determinant of sustained injection cessation among chronic drug users: the interface with social factors and service utilization.

AIMS: The objective of this study was to identify factors associated with sustained injection cessation and to examine further the relationship between the occurrence of sustained injection cessation of injection drug users (IDUs) and prior injection frequency. DESIGN AND SETTING: IDUs in the Montreal St Luc Cohort who had at least three consecutive interviews between 1995 and 1999 were included. Sustained injection cessation was defined as a period of at least 7 consecutive months without injection. All IDUs completed interview-administered questionnaires on socio-demographic characteristics, drug and sexual behaviours and health-related issues. Logistic regression was used for analyses. FINDINGS: A total of 186/1004 (18.5%) IDUs reported a period of sustained injection cessation during the study period. In multivariate analysis, HIV-positive status, 'booting' and cumulative time spent in prison were negatively associated with injection cessation, while injection initiation after 35 years of age and frequent crack use were positively associated with injection cessation. We found a negative association between the occurrence of injection cessation and the frequency of injection; the odds ratios (OR) for cessation were 0.49 [95% confidence interval (CI): 0.03, 0.78] for IDUs who injected 30-100 times and 0.21 (95% CI: 0.10, 0.46) for IDUs who injected more than 100 times in the previous month. Attending needle exchange programmes (NEPs) or pharmacies appeared to be a modifier of the relation between cessation and prior injection frequency. The OR was 0.68 (95% CI: 0.42, 1.12) for IDUs who injected 30-100 times prior to injection and attended NEPs or pharmacies and was 0.07 (0.01, 0.30) for IDUs who did not use these services. CONCLUSIONS: Overall, a fifth of IDUs experienced at least one episode of injection cessation of 7 months or more during a period of 4.5 years. Our data suggest that NEPs and pharmacies may have played a role in inducing injection cessation episodes in a subgroup of IDUs. Research is needed to better identify the characteristics of IDUs who could benefit from an injection cessation intervention strategy. This information is important for social and health policy planning.

Adolescent↗

PubMed2001

Dermal injection of radioactive colloid is superior to peritumoral injection for breast cancer sentinel lymph node biopsy: results of a multiinstitutional study.

OBJECTIVE: To determine the optimal radioactive colloid injection technique for sentinel lymph node (SLN) biopsy for breast cancer. SUMMARY BACKGROUND DATA: The optimal radioactive colloid injection technique for breast cancer SLN biopsy has not yet been defined. Peritumoral injection of radioactive colloid has been used in most studies. Although dermal injection of radioactive colloid has been proposed, no published data exist to establish the false-negative rate associated with this technique. METHODS: The University of Louisville Breast Cancer Sentinel Lymph Node Study is a multiinstitutional study involving 229 surgeons. Patients with clinical stage T1-2, N0 breast cancer were eligible for the study. All patients underwent SLN biopsy, followed by level I/II axillary dissection. Peritumoral, subdermal, or dermal injection of radioactive colloid was performed at the discretion of the operating surgeon. Peritumoral injection of isosulfan blue dye was performed concomitantly in most patients. The SLN identification rates and false-negative rates were compared. The ratios of the transcutaneous and ex vivo radioactive SLN count to the final background count were calculated as a measure of the relative degree of radioactivity of the nodes. One-way analysis of variance and chi-square tests were used for statistical analysis. RESULTS: A total of 2,206 patients were enrolled. Peritumoral, subdermal, or dermal injection of radioactive colloid was performed in 1,074, 297, and 511 patients, respectively. Most of the patients (94%) who underwent radioactive colloid injection also received peritumoral blue dye injection. The SLN identification rate was improved by the use of dermal injection compared with subdermal or peritumoral injection of radioactive colloid. The false-negative rates were 9.5%, 7.8%, and 6.5% (not significant) for peritumoral, subdermal, and dermal injection techniques, respectively. The relative degree of radioactivity of the SLN was five- to sevenfold higher with the dermal injection technique compared with peritumoral injection. CONCLUSIONS: Dermal injection of radioactive colloid significantly improves the SLN identification rate compared with peritumoral or subdermal injection. The false-negative rate is also minimized by the use of dermal injection. Dermal injection also is associated with SLNs that are five- to sevenfold more radioactive than with peritumoral injection, which simplifies SLN localization and may shorten the learning curve.

Breast Neoplasms↗

PubMed2005

Injections in patients with osteoarthritis and other musculoskeletal disorders: use of synthetic injection models for teaching physiatry residents.

This study examined whether resident injection skills could be enhanced using synthetic injection models. A total of 30 physiatry residents underwent written and injection-model pretesting and posttesting. After randomization into injection-model and control groups, the experimental group trained by watching an instructional videotape and by using models that gave visual feedback on injection accuracy, whereas the control group studied technical aspects of injections. Immediately after patient injections, a blinded attending graded residents on the required level of verbal or manual assistance. The experimental group performed significantly better during patient injections as per first injection data (i.e., the scores obtained from performing a procedure for the first time on each particular body region; P = 0.013), total injection data (i.e., the mean scores obtained from performing all procedures on each particular body region; P = 0.017), and postrotation practical testing (P < 0.007) but not for didactic knowledge (postrotation written testing; P < 0.039). Data analysis by body region showed significant benefit only for occasionally performed patient injection procedures. The benefit was most evident in less experienced residents. Injection-model accuracy testing correlated with actual patient injections, both for first injections into each major body region (r = 0.52, P = 0.005) and for all injections (r = 0.55, P = 0.003). Consideration should be given for incorporating injection-model training into residency education, especially for residents with less injection experience and for occasionally performed procedures. The overall correlation between model practical testing and subsequent patient injection performance suggests that models can measure injection competence.

Clinical Competence↗

PubMed2001

Geographical injecting locations among injecting drug users in Sydney, Australia.

AIMS: To document the geographical injection locations of IDU, and the factors and harms associated with injecting in public places. DESIGN: Cross-sectional survey. SETTING: Sydney, Australia. PARTICIPANTS: Two hundred injecting drug users. FINDINGS: Nearly all subjects (96%) had injected in a public place, and 89% had done so in the preceding 6 months. Large proportions had injected in all locations studied, including cars (90%), public toilets (81%), the street (80%) and trains (55%). Injecting in public places also occurred frequently, with 53% of subjects having injected often in at least one public location during the preceding 6 months. Twenty-seven per cent of subjects had injected often in the street over the preceding 6 months, 22% had injected often in cars and 17% had injected often in public toilets. Frequent injectors in public places were more likely to be male, and to have overdosed in the preceding 6 months, injected significantly more drug classes in the preceding 6 months, injected in more bodily injecting sites in the preceding 6 months and had more current injection-related problems than other IDU. CONCLUSIONS: Injecting in public places was practiced by the overwhelming majority of the sample, and a pattern of increased harm was associated with frequent public injecting. In attempting to quantify the harm associated with injecting, and to reduce such harm, the locations injections take place in are of major importance.

Adolescent↗

PubMed2005

Co-injection of air and steam for the prevention of the downward migration of DNAPLs during steam enhanced extraction: an experimental evaluation of optimum injection ratio predictions.

When steam is injected into soil containing a dense volatile non-aqueous phase liquid contaminant, the DNAPL vaporized within the heated soil region condenses and accumulates ahead of the steam condensation front. If enough DNAPL accumulates, gravitational forces can overcome trapping forces allowing the liquid contaminant to flow downward. By injecting air with steam, a portion of the DNAPL vapor remains suspended in equilibrium with the air, decreasing liquid contaminant accumulation ahead of the steam condensation front, and thus reducing the possibility of downward migration. In a previous work, a theoretical model was developed to predict the optimum injection ratio of air to steam that would eliminate accumulation of DNAPL ahead of the temperature front and thus minimize the potential for downward migration. In this work, the theoretical model is summarized, and an experiment is presented in order to evaluate the optimum injection ratio prediction. In the experiment, a two-dimensional water saturated sand pack is contaminated with a known mass of TCE (DNAPL). The system is then remediated by co-injecting air and steam at the predicted optimum injection ratio, calculated based on the average contaminant soil concentration in the sand pack. Results for the co-injection of air and steam are compared to results for the injection of pure steam or pure air. Injection at the predicted optimum injection ratio for a volumetric average NAPL saturation, reduced accumulation of the contaminant ahead of the condensation front by over 90%, as compared to steam injection alone. This indicates that the optimum injection ratio prediction is a valuable tool for limiting the spreading of DNAPL during steam-enhanced extraction. Injection at the optimum injection ratio resulted in earlier recovery of contaminant than for steam injection alone. Co-injection of steam and air is also shown to result in much higher recovery rates than air injection alone.

Air↗

PubMed1999

Risk factors among IDUs who give injections to or receive injections from other drug users.

AIMS: To assess risk factors associated with injection drug users (IDUs) who give injections to or receive injections from other IDUs. DESIGN AND SETTING: IDUs were recruited into a cross-sectional study using targeted sampling methods in Oakland, Richmond, and San Francisco, California from August 1996 to January 1997. "Street docs" are IDUs who reported having given injections to other IDUs in the past month. "Injection recipients" are IDUs who reported having received injections from other people in the past month. PARTICIPANTS: Of 1166 IDUs interviewed, 283 (24%) reported being injection recipients and 427 (37%) reported being street docs. MEASUREMENTS: Socio-demographic characteristics and injection-related risk behaviors. FINDINGS: Injection recipients and street docs were significantly more likely (p < 0.001) than other IDUs to report sharing syringes (33% of injection recipients, 21% of street docs and 7% of others), cookers (71% of injection recipients, 55% of street docs and 24% of others), rinse water (44% of injection recipients, 35% of street docs and 13% of others), and filters (60% of injection recipients, 47% of street docs and 20% of others). In a logistic regression model, injection recipients (adjusted odds ratio (AOR) = 4.29) and street docs (AOR = 1.91) were more likely than other IDUs to report having shared syringes. CONCLUSIONS: Giving and receiving injections is common among IDUs in the San Francisco Bay area. Qualitative and epidemiological studies are needed to understand better the infectious disease risks associated with giving and receiving injections. Interventions need to address these issues and provide practical solutions.

Adult↗

PubMed1999

Lunelle monthly contraceptive injection (medroxyprogesterone acetate and estradiol cypionate injectable suspension): steady-state pharmacokinetics of MPA and E2 in surgically sterile women.

The steady-state pharmacokinetics and pharmacodynamics of medroxyprogesterone acetate (MPA) and estradiol (E2, released from E2C by esterase enzymes) were characterized after administration to surgically sterile women. This report describes the pharmacokinetics of this multiple-dose and open-labeled study (pharmacodynamics are reported in a subsequent article in this issue). Women with regular menstrual cycles were studied for one control cycle, 3 consecutive treatment months, and 3-5 months of follow-up. Blood samples were drawn before each monthly dose and at specified time points after the third monthly injection. A total of 16 women were enrolled, 14 of whom completed the study. These 14 women (13 white, one black) ranged in age from 28 to 43.4 years, in body weight from 47.6 to 68.9 kg, and in height from 150 to 175 cm. Mean serum MPA concentrations peaked in the first week after administration of MPA/E2C (Lunelle Monthly Contraceptive Injection). The mean MPA Cmax and AUC0-t(last) were 1.25 ng/mL and 32.13 ng.day/mL, respectively. Serum MPA concentrations declined with a mean terminal half-life of 14.7 days, indicating that absorption from the injection site is prolonged after administration of MPA/E2C. The time for MPA concentrations to fall below the lower limit of quantitation (i.e., < 10 pg/mL) after the third injection ranged from 63 to 84 days. The average MPA trough (Cmin' day 28) concentrations for the three consecutive monthly injections ranged from 0.44 to 0.47 pg/mL, indicating that steady-state conditions were achieved after the first injection. The MPA Cmin values were well above threshold levels required to suppress ovulation throughout the injection interval. Absorption of E2 from the injection site was also prolonged after injection of MPA/E2C. Mean concentrations of E2 peaked at approximately 2 days after the third injection, and the average Cmax was 247 pg/mL. Serum E2 levels declined with a terminal half-life of approximately 8 days; E2 levels returned to baseline (typically, approximately 100 pg/mL) by 14 days after each injection. The average trough (Cmin' day 28) levels for E2 ranged from 40 to 55 pg/mL. The results of this study demonstrate that steady-state conditions are achieved after the first injection of MPA/E2C; no further MPA or E2 accumulation occurs beyond the first injection. Furthermore, the E2 peak observed after injection of MPA/E2C is similar to the nontreated preovulatory E2 range and returns to baseline levels by approximately 14 days after injection.

Absorption↗

PubMed2002

Intravenous micro-particle injections and pulmonary hypertension in broiler chickens: acute post-injection mortality and ascites susceptibility.

Intravenously injected micro-particles become trapped within the pulmonary vasculature where they increase the resistance to blood flow and trigger pulmonary hypertension. We tested the hypothesis that i.v. micro-particle injections can be used to trigger acute (24 to 48 h) post-injection mortality in broilers having the most limited pulmonary vascular capacity, or ascites in broilers whose marginal cardiopulmonary capacity renders them susceptible to pulmonary hypertension syndrome (PHS). Progressive inflammation-associated responses were initiated within the lung parenchyma by 10 to 80 microm diameter dextran polymer (Sephadex) and 30 microm diameter cellulose micro-particles, leading to the scavenging of Sephadex micro-particles from the pulmonary vasculature by <5 d post-injection, whereas the cellulose micro-particles persisted for >7 d post-injection. The persistency and size of the cellulose apparently facilitated chronic occlusion of blood flow through precapillary arterioles, thereby triggering appreciable post-injection mortality and PHS at relatively low injection volumes (0.3 to 0.6 mL at 0.02 g/mL). In contrast, the small size of the polystyrene microspheres (15 microm), and the lack of persistency of the Sephadex micro-particles, apparently precluded the reliable occurrence of post-injection mortality or PHS until higher volumes (>0.8 mL at 0.02 g/mL) were injected. Values for the total susceptibility index (TSI: 24 to 48 h post-injection mortality + PHS mortality) following cellulose injections were higher for broilers reared at cool temperatures than at thermoneutral temperatures. The incidences of PHS induced by exposing broilers from different genetic lines to constant cool temperatures qualitatively paralleled the respective post-injection mortalities elicited by injecting the cellulose micro-particle suspension into the same lines. These observations indicate the micro-particle injection methodology potentially can replace unilateral pulmonary artery occlusion as the technique of choice for genetically selecting broilers that have a sufficiently robust pulmonary vascular capacity to resist the onset of pulmonary hypertension and PHS. The functional importance of the relative antigenicity of different micro-particle types, and the extent to which key immune-mediated responses, either beneficial or detrimental, might be co-selected by the micro-particle injection technology, remain to be clarified.

Animals↗

PubMed2003

The injection of methadone syrup in New South Wales: patterns of use and increased harm after partial banning of injecting equipment.

OBJECTIVE: To describe methadone injectors and the risk practices associated with injecting methadone in New South Wales, Australia. To assess the impact on injecting drug use and risk behaviour of the withdrawal of methadone injecting equipment from government-funded needle and syringe programs. METHOD: Cross-sectional survey, conducted in 1999, of 206 people who had injected methadone at least once in the previous month. Participants were from Central Sydney, West Sydney and rural New South Wales. RESULTS: Of participants who had injected both methadone and other drugs in the previous month (n=162), significantly more reused their methadone injecting equipment compared with those who reused their other drug injecting equipment (60% vs. 28%, p<0.01). There was no significant difference in terms of sharing injecting equipment, with 19% reporting sharing methadone injecting equipment and 14% sharing other drug injecting equipment. However, women were more likely than men to share methadone injecting equipment. Over half of the participants had accessed diverted methadone and a substantial minority reported the use of public spaces for injecting methadone. CONCLUSIONS: Our results suggest that the current policy has led to increased reuse of equipment for injecting methadone. IMPLICATIONS: A range of other possible policy options, such as closer monitoring and dilution of take-home doses, increasing oral doses and implementing trials of injected methadone, may assist to reduce the prevalence of methadone syrup injection and related harms.

Administration, Oral↗

PubMed1988

[Comparison of two intramuscular injection technics on the severity of discomfort and lesions at the injection site].

The purpose of this study was to compare the effect of the Z-track intramuscular injection technique with the effect of the stand and intramuscular injection technique on the severity of discomfort and lesions at the injection site. The subjects of the study were 20 patients with only early tuberculosis excluding another abnormalities (a skin rash, allergy to topical use of alcohol, jaundice, edema, neurosensory abnormality, coagulation defects, obesity and thin). Data collection was done from Feb. 1 to March 15, 1988 by means of Korean Pain Measurement Tool, Visual Analogue Scale, and Objective measures of injection site lesions. The results of this study were as follows: 1) Hypothesis 1; "The severity of subject discomfort is less following administration of the Z-track intramuscular injection technique than following administration injection technique." was not supported. 2) Hypothesis 2; "The degrees of severity subject discomfort is less following administration of the Z-track intramuscular injection technique than following administration of the standard intramuscular injection technique." was not supported. 3) Hypothesis 3; "The severity of injection sites lesions is less following administration of the Z-track intramuscular injection technique than following administration of the standard intramuscular injection techniques." was not supported. 4) The terms that were selected included factor II (mild-moderate pain) of Ratio Scale Measuring Pain using Korean Pain Terms. In conclusion; it was found that there was not a difference from the severity of subject discomfort between two groups, but the degrees of severity of subject discomfort about following administration of the Z-track intramuscular injection was tended to be declined. Therefore further studies suggest that the Z-track intramuscular injection technique can decrease the severity of discomfort in persons receiving frequently intramuscular injections. First of all, it is necessary to be developed an effect tool of dis comfort measurement for the intramuscular injection in Korean.

Humans↗

PubMed2001

High injection pressure during intralesional injection of corticosteroids into capillary hemangiomas.

BACKGROUND: Intralesional injection of corticosteroids is an effective treatment for tumors of the head and neck. Complications are rare but include permanent loss of vision. We designed a study to investigate the mechanism for this complication. METHODS: Three fellowship-trained pediatric ophthalmologists participated in the study in a nonmasked fashion. Four patients received 5 separate treatment sessions of an intralesional injection of a 50-50 mixture of triamcinolone diacetate (40 mg/mL) and betamethasone sodium phosphate and betamethasone acetate (6 mg/mL) into capillary hemangiomas. Injection pressure was obtained in real time using a cannula designed for this purpose. Maximum pressure, mean pressure, and volume of corticosteroid were measured from each injection. RESULTS: A total of 71 injections (range, 8-33 injections per patient) was performed. The total volume of corticosteroid ranged from 0.9 to 2.1 mL. In 63 of 71 injections, the maximum pressure exceeded 100 mm Hg (range, 18.65-842.18 mm Hg). Each surgeon produced injection pressures greater than the systemic arterial pressures of each patient. CONCLUSIONS: Injection pressures exceeding the systemic arterial pressures routinely occur during intralesional injections of corticosteroids into capillary hemangiomas. Experienced surgeons participating in a nonmasked protocol were unable to prevent high injection pressures of corticosteroid. A sufficient volume of corticosteroid injected at high injection pressure would account for the embolization of corticosteroid particles into the ocular circulation from retrograde arterial flow. We recommend limiting the volume of corticosteroid and performing indirect ophthalmoscopy on all patients receiving injections of long-acting corticosteroids into the orbit and periorbital soft tissue.

Betamethasone↗

PubMed2002

Indwelling catheters used from the onset of diabetes decrease injection pain and pre-injection anxiety.

OBJECTIVES: To investigate the use of indwelling catheters as injection aids at diabetes onset to reduce injection pain and pre-injection anxiety. STUDY DESIGN: Forty-one patients aged 8.1 +/- 3.7 years (range, 1-15) participated in this open, controlled randomized study. A 10-cm VAS with faces was used for scoring. A local anesthetic cream was used before all insertions. The control group used insulin pens with standard needles. After one week, the indwelling catheter group could choose regular injections but were included in the "intention to treat" analysis. RESULTS: Injection pain and anxiety decreased from day 1 to 15 in both groups (average, 4.1 injections/day). Pain was significantly lower for indwelling catheter injections when scored by parents (median, 1.2 cm vs 2.7 cm; P =.002), children/teenagers (0.8 cm vs 1.5 cm; P =.006), and nurses (1.4 cm vs 3.0 cm; P =.002). Parental pre-injection anxiety was also lower (1.2 cm vs 2.9 cm; P =.016). Taking injections, including inserting catheters, was found to be less problematic with an indwelling catheter (1.6 cm vs 3.3 cm;P =.009). During the 6-month follow-up, injection pain and injection problems were significantly lower in the catheter group. Mean catheter indwelling time was 3.7 days. Median pain for catheter insertion was 2.1 cm and for glucose testing was 0.9 cm. Sixteen of 20 patients continued to use indwelling catheters after 2 weeks, and 9 of 20 after 6 months. CONCLUSIONS: We found an evident relief of pre-injection anxiety and injection pain when using indwelling catheters for introducing insulin injections at the onset of diabetes.

Adolescent↗

PubMed2004

Augmentation of pedicle screw fixation strength using an injectable calcium phosphate cement as a function of injection timing and method.

STUDY DESIGN: Axial pullout tests using fresh cadaveric thoracolumbar vertebral bodies. OBJECTIVES: To evaluate the effect of a new injectable calcium phosphate cement on the axial pullout strength of both revised and augmented pedicle screws in comparison with polymethyl methacrylate and in terms of injection method. SUMMARY OF BACKGROUND DATA: Failure of pedicle screws by loosening and back out remains a significant clinical problem and is of particular concern for patients with low bone quality. Polymethyl methacrylate was shown to significantly improve the screw pullout strength. However, polymethyl methacrylate is known to have a high polymerization temperature, which may damage surrounding tissues, and a short handling time, and it lacks long-term biocompatibility. Bone mineral cements such as calcium phosphate have a longer working time, very low thermal effect, and are biodegradable as well as having good mechanical strength. Recently, new calcium phosphate cement with improved infiltration properties for better injectability has been introduced, but its performance in augmenting the pedicle screw fixation has not been tested yet. METHODS: The bone mineral densities of 52 vertebral bodies (T11-L5) were measured using dual-energy x-ray absorptiometry. In each vertebral body, a 6.5-mm-diameter and 45 +/- 5-mm-long pedicle screw was inserted into either the right or left pedicle, representing an initial intact implantation. These intact screws were pulled axially until failure at 10 mm/min. Following failure of the intact pedicle, 3.0 cc of cement was injected into the failed screw hole, representing a revision case, and the prepared screw hole in the contralateral intact pedicle representing an augmentation case. The cement was injected either to the distal tip of the screw hole (calcium phosphate-1 group, n = 19) or along the entire length of the screw hole (calcium phosphate-2 group, n = 20), and the screws were inserted. The cement was then allowed to cure for 24 hours at room temperature before both screws were pulled to failure. In 13 specimens, polymethyl methacrylate was injected along the entire length of the screw hole (polymethyl methacrylate group). Kruskal-Wallis and Mann-Whitney tests were used to compare the screw pullout strengths for study groups, whereas linear relationships between variables were assessed with scatter plots and Spearman correlation coefficients with a significance level of 0.05. RESULTS: Mean bone mineral densities of all groups were similar. A significant positive correlation was seen between bone mineral density and intact pullout strength. In revision, the pullout strength of calcium phosphate-1 was similar to that of intact, whereas the pullout strength of calcium phosphate-2 and polymethyl methacrylate was significantly greater than that of intact. In augmentation, all 3 injection methods significantly improved the pullout strength over intact. Injection of the calcium phosphate cement along the entire screw length was found to produce significantly higher pullout strengths than injection only at the distal tip of the screw in revision case. Injection of polymethyl methacrylate produced significantly higher pullout strengths than the injection of calcium phosphate by either method in both revision and augmentation. CONCLUSION: Results of this study demonstrate that the new calcium phosphate cement can improve the axial pullout strength of revised and augmented pedicle screws when injected along the entire length of the screw. This suggests that the injection method may be crucial for revision of failed pedicle screws. Considering inherent properties more favorable for in vivo application, such as nonexothermal polymerization and longer working time, and significant improvement in pullout strength, the new calcium phosphate cement may be a good alternative to polymethyl methacrylate for the augmentation of pedicle screw fixation.

Aged↗

PubMed2004

A randomized comparative study of short term response to blind injection versus sonographic-guided injection of local corticosteroids in patients with painful shoulder.

OBJECTIVE: Local corticosteroid injections, commonly accepted by rheumatologists to be effective treating painful shoulder, have shown controversial results. High frequency ultrasonography is an accurate and safe imaging modality for guiding musculoskeletal injections. We prospectively compared the short term response to randomized blind injection versus sonographic-guided injection of local corticosteroid in patients with painful shoulder. METHODS: We studied 41 consecutive patients with painful shoulder. Patients with previous trauma or chronic inflammatory arthritis were excluded. No patient had received previous physiotherapy or local steroid injection in the shoulder. Patients were randomized to receive either a blind subacromial injection of 20 mg triamcinolone (Group 1, n = 20) or a sonographic guided injection of 20 mg triamcinolone (Group 2, n = 21) by the same rheumatologist blinded to the clinical evaluation. In both groups we recorded shoulder abnormalities and the location of the steroid postinjection by ultrasound. Each patient was clinically assessed within 5 days before injection and 6 weeks after injection by another rheumatologist without knowledge of the injection technique performed. Clinical assessment included demographic and clinical data, a visual analog scale (VAS) for pain (0-100), the Shoulder Function Assessment (SFA) scale (0-70), and postinjection adverse effects. No patient received physical therapy during the followup period. Initially, demographic, clinical, and ultrasonographic findings in both groups showed no significant differences. RESULTS: Six weeks after injection, the VAS and the SFA score showed a significantly greater improvement in Group 2 compared with Group 1 (mean VAS score change 34.9 for Group 2 vs 7.1 for Group 1, p < 0.001; and mean SFA score change 15 for Group 2 vs 5.6 for Group 1, p = 0.012). One patient in Group 1 reported mild postinjection adverse effects. CONCLUSION: We suggest that sonographic-guided corticosteroid injections should be indicated, at least, in patients with poor response to previous blind injection to ensure accurate medication placement in order to improve therapeutic effectiveness.

Adrenal Cortex Hormones↗

PubMed2001

Potential risk factors for the transition to injecting among non-injecting heroin users: a comparison of former injectors and never injectors.

AIMS: To compare potential risk factors for the transition to injecting among non-injecting heroin users (NIUs) with different injecting histories. DESIGN: Cross-sectional data from baseline structured interviews with NIUs in a study on transitions to injecting. Sample recruited by outreach or chain-referral in New York City (NYC), 1996-1998. SETTING: Recruitment of sample and interviews conducted in a NYC neighborhood where many drug users reside and/or use drugs. PARTICIPANTS: Of 575 NIUs, 67% had never injected; 16% had injected one to nine times (infrequent former injectors (IFI)); and 18% 10 or more times (frequent former injectors (FFI)). MEASUREMENTS: Controlling for age and race/ethnicity, adjusted odds ratios were estimated in multivariate logistic regression, and differences in means tested by ANCOVA. FINDINGS: FFI (compared to never injectors and IFI) were more likely: to be homeless; to be unemployed; to be long-time users; to be younger at first heroin use; to not have initiated heroin use through non-injected routes; to not be afraid of injecting themselves with needles; to sniff heroin with former IDUs; and, for both men and women separately, to have sex partners who were former IDUs. Both FFI and IFI were twice as likely as never injectors to perceive that their friends thought that it was "OK" to inject drugs. CONCLUSIONS: FFI have multiple individual and network characteristics that may increase their risk of injecting drugs. Interventions among NIUs to prevent transitions to injecting need to ascertain NIUs' injecting history and address the many potential risks that FFI have for resuming injecting drug use.

Adolescent↗

PubMed2003

Gender differences in sexual and injection risk behavior among active young injection drug users in San Francisco (the UFO Study).

Female injection drug users (IDUs) represent a large proportion of persons infected with HIV in the United States, and women who inject drugs have a high incidence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. Therefore, it is important to understand the role of gender in injection risk behavior and the transmission of blood-borne virus. In 2000-2002, 844 young (<30 years old) IDUs were surveyed in San Francisco. We compared self-reported risk behavior between 584 males and 260 female participants from cross-sectional baseline data. We used logistic regression to determine whether demographic, structural, and relationship variables explained increased needle borrowing, drug preparation equipment sharing, and being injected by another IDU among females compared to males. Females were significantly younger than males and were more likely to engage in needle borrowing, ancillary equipment sharing, and being injected by someone else. Females were more likely than males to report recent sexual intercourse and to have IDU sex partners. Females and males were not different with respect to education, race/ethnicity, or housing status. In logistic regression models for borrowing a used needle and sharing drug preparation equipment, increased risk in females was explained by having an injection partner who was also a sexual partner. Injecting risk was greater in the young female compared to male IDUs despite equivalent frequency of injecting. Overlapping sexual and injection partnerships were a key factor in explaining increased injection risk in females. Females were more likely to be injected by another IDU even after adjusting for years injecting, being in a relationship with another IDU, and other potential confounders. Interventions to reduce sexual and injection practices that put women at risk of contracting hepatitis and HIV are needed.

Adolescent↗