A suggested algorithm for detection of multi drug-resistant tuberculosis in Zimbabwe.

INTRODUCTION: Rapid genotypic and phenotypic methods for multi-drug-resistant-tuberculosis (MDR-TB) detection are now widely available. Zimbabwe adopted the use of GeneXpert-MTB/RIF, microscopic-observation-drug-susceptibility-assay (MODS) and Mycobacteria-Growth-Indicator-Tube (MGIT) drug-susceptibility-testing (DST). Data is limited on the ideal combination of use of these methods in resource limited settings. METHODOLOGY: Between August 2014 to July 2015, 211 sputa from MDR-TB suspects were tested with GeneXpert-MTB/RIF, MODS, manual-MGIT and Lowenstein-Jensen (LJ)-DST to determine diagnostic accuracy and turnaround-time (TAT), with LJ-DST as the gold standard. A performance score ranking table for diagnostic accuracy, TAT, costs, facilities and expertise requirements, was used to determine the most favourable tool. RESULTS: GeneXpert-MTB/RIF sensitivity was 96% (95%CI:80-100) and specificity was 95% (95%CI:90-97). MODS sensitivity was 88% (95%CI:68-97) and specificity was 97% (95%CI:87-100). Manual MGIT-DST had slightly lower sensitivity of 80% (95%CI:59-93). Median time to detection of MDR-TB was <1 day (IQR:0-0) for Xpert, 14 days (IQR:11-31) for MODS, 21 days (IQR:7-22) for MGIT-DST and 28 days (IQR:25-28) for LJ-DST. Operational costs for MODS, MGIT-DST, and GeneXpert-MTB/RIF were $21.20, $27.52 and $39.76 respectively. From a summation of scores including facility and expertise requirements per diagnostic technique, GeneXpert-MTB/RIF was the most favourable tool, followed by MODS and MGIT-DST. CONCLUSIONS: For best scale-up of MDR-TB diagnosis in Zimbabwe, GeneXpert-MTB/RIF can be used for rapid detection of TB in smear negative cases, RIF-susceptibility for early treatment initiation and probable MDR-TB. MODS can rapidly confirm probable MDR-TB detected by GeneXpert-MTB/RIF, manual-MGIT can provide early results for susceptibility to other antibiotics, with affordable costs, with LJ-DST confirming discordant DSTs.

Bacteremia, causative agents and antimicrobial susceptibility among HIV-1-infected children on antiretroviral therapy in Uganda and Zimbabwe.

BACKGROUND: Bacteremia is common in HIV-infected children in Africa, including after start of antiretroviral therapy (ART), but there are limited data on causative pathogens and their antimicrobial sensitivity patterns in this population. METHODS: We analyzed data on blood cultures taken from HIV-infected children developing acute febrile illness after enrollment to the Antiretroviral Research for Watoto (ARROW) clinical trial in Uganda and Zimbabwe. Patterns of bacterial pathogens and their antimicrobial susceptibilities were determined and bacteremia rates calculated over time from ART initiation. RESULTS: A total of 848 blood cultures were obtained from 461 children, of which 123 (14.5%) from 105 children (median age 3.5 years, 51% girls) were culture positive, including 75 (8.8%) with clearly pathogenic organisms. The event rates for positive cultures with clearly pathogenic organisms after 0-1, 2-3, 4-11 and ≥12 months on ART were 13.3, 11.4, 2.1 and 0.3 per 1000 person-months of follow-up, respectively. The pathogens isolated (n; %) were Streptococcus pneumoniae (36; 28.3%), Staphylococcus aureus (11; 8.7%), Klebsiella pneumoniae (6; 4.7%), Pseudomonas aeruginosa (6; 4.7%), Salmonella spp (6; 4.7%), Escherichia coli (5; 3.9%), Haemophilus influenzae (1; 0.8%) and fungal spp (4; 3.1%). Other bacteria of doubtful pathogenicity (n = 52; 42%) were also isolated. Most isolates tested were highly (80-100%) susceptible to ceftriaxone, cefotaxime and ciprofloxacin; very few (~5%) were susceptible to cotrimoxazole; S. pneumoniae had high susceptibility to amoxicillin/ampicillin (80%). CONCLUSIONS: Rates of proven bacteremia were >20-fold higher immediately after starting ART compared with 12 months later in African HIV-infected children. S. pneumoniae was most commonly isolated, suggesting need for pneumococcal vaccination and effective prophylactic antibiotics.

Transabdominal electrical stimulation increases colonic propagating pressure waves in paediatric slow transit constipation.

BACKGROUND AND AIMS: In slow-transit constipation (STC) pancolonic manometry shows significantly reduced antegrade propagating sequences (PS) and no response to physiological stimuli. This study aimed to determine whether transcutaneous electrical stimulation using interferential current (IFC) applied to the abdomen increased colonic PS in STC children. METHODS: Eight children (8-18 years) with confirmed STC had 24-h colonic manometry using a water-perfused, 8-channel catheter with 7.5 cm sidehole distance introduced via appendix stomas. They then received 12 sessions (20 min/3× per week) of IFC stimulation (2 paraspinal and 2 abdominal electrodes), applied at a comfortable intensity (<40 mA, carrier frequency 4 kHz, varying beat frequency 80-150 Hz). Colonic manometry was repeated 2 (n=6) and 7 (n=2) months after IFC. RESULTS: IFC significantly increased frequency of total PS/24h (mean ± SEM, pre 78 ± 34 vs post 210 ± 62, p=0.008, n=7), antegrade PS/24h (43 ± 16 vs 112 ± 20, p=0.01) and high amplitude PS (HAPS/24h, 5 ± 2:10 ± 3, p=0.04), with amplitude, velocity, or propagating distance unchanged. There was increased activity on waking and 4/8 ceased using antegrade continence enemas. CONCLUSIONS AND INFERENCES: Transcutaneous IFC increased colonic PS frequency in STC children with effects lasting 2-7 months. IFC may provide a treatment for children with treatment-resistant STC.

Lopinavir/ritonavir monotherapy after 24 weeks of second-line antiretroviral therapy in Africa: a randomized controlled trial (SARA).

BACKGROUND: Boosted protease inhibitor (bPI) monotherapy (bPImono) potentially has substantial cost, safety and operational benefits. It has never been evaluated as second-line antiretroviral therapy (ART) in Africa. METHODS: After 24 weeks of lopinavir/ritonavir-containing second-line therapy, DART participants were randomized to remain on combination therapy (CT), or change to bPImono maintenance (SARA trial; ISRCTN53817258). Joint primary end points were CD4(+) T-cell changes 24 weeks later and serious adverse events (SAEs); retrospectively assayed viral load (VL) was a secondary end point. Analyses were intention-to-treat. RESULTS: A total of 192 participants were randomized to CT (n=95) or bPImono (n=97) and followed for median 60 weeks (IQR 45-84). Participants received median 4.0 years (IQR 3.5-4.4) first-line ART. Median CD4(+) T-cell count at first-line failure was 86 cells/mm(3) (47-136), increasing to 245 cells/mm(3) (173-325) after 24-week induction when 77% had VL<50 copies/ml. Overall, 44 (23%) were receiving second-line therapy with bPI and nucleoside reverse transcriptase inhibitors (NRTI) only, and 148 (77%) with bPI plus non-NRTI (NNRTI) with or without NRTI. At 24 weeks after randomization to CT versus bPImono, mean CD4(+) T-cell increase was 42 (CT, n=85) versus 49 cells/mm(3) (bPImono, n=88; adjusted difference 13 [95% CI -15, 43], P=0.37; non-inferior compared with predetermined non-inferiority margin [-33]). Virological suppression was greater for CT versus bPImono (trend P=0.009): 77% (70/91) versus 60% (56/94) were <50 copies/ml, and 5% (5) versus 14% (13) were ≥1,000 copies/ml, respectively. A total of 0 (0%) versus 5 (5%) participants had major protease inhibitor mutations and 3 (3%) versus 0 (0%) new NNRTI/NRTI mutations were detected during follow-up. Two participants (1 CT and 1 bPImono) died >24 weeks after randomization, and 5 (2 CT and 3 bPImono) experienced SAEs (P=0.51). CONCLUSIONS: bPImono following a 24-week second-line induction was associated with similar CD4(+) T-cell response, but increased low-level viraemia, generally without protease inhibitor resistance. Longer-term trials are needed to provide definitive evidence about effectiveness in Africa.

Long-term effects of transabdominal electrical stimulation in treating children with slow-transit constipation.

AIMS: Transcutaneous electrical stimulation (TES) was used to treat children with slow-transit constipation (STC) for 1 to 2 months in a randomized controlled trial during 2006 to 2008. We aimed to determine long-term outcomes, hypothesizing that TES produced sustained improvement. METHODS: Physiotherapists administered 1 to 2 months of TES to 39 children (20 minutes, 3 times a week). Fifteen continued to self-administer TES (30 minutes daily for more than 2 months). Mean long-term follow-up of 30 of 39 patients was conducted using questionnaire review 3.5 years (range 1.9-4.7 years) later. Outcomes were evaluated by confidence intervals or paired t test. RESULTS: Seventy-three percent of patients perceived improvement, lasting more than 2 years in 33% and less than 6 months in 25% to 33%. Defecation frequency improved in 30%. Stools got wetter in 62% after stimulation and then drier again. Soiling improved in 75% and abdominal pain in 59%. Laxative use stopped in 52%, and 43% with appendicostomies stopped washouts. Soiling/Holschneider continence score improved in 81% (P = .0002). Timed sits switched to urge-initiated defecations in 80% patients. Eighty percent of relapsed patients elected to have home stimulation. CONCLUSION: TES holds promise for STC children. Improvement occurred in two thirds of children, lasting more than 2 years in one third, whereas symptoms recurred after 6 months in one third of children.

Slow-transit constipation with concurrent upper gastrointestinal dysmotility and its response to transcutaneous electrical stimulation.

PURPOSE: Transcutaneous electrical stimulation (TES) speeds up colonic transit in children with slow-transit constipation (STC). This study examined if concurrent upper gastrointestinal dysmotility (UGD) affected response to TES. METHODS: Radio-nuclear transit studies (NTS) were performed before and after TES treatment of STC as part of a larger randomised controlled trial. UGD was defined as delayed gastric emptying and/or slow small bowel transit. Improvement was defined as increase of ≥1 Geometric Centre (median radiotracer position at each time [small bowel = 1, toilet = 6]). RESULTS: Forty-six subjects completed the trial, 34 had NTS after stimulation (21 M, 8-17 years, mean 11.3 years; symptoms >9 years). Active stimulation increased transit in >50% versus only 25% with sham (p = 0.04). Seventeen children also had UGD. In children with STC and either normal upper GI motility (NUGM) and UGD, NTS improved slightly after 1 month (57 vs. 60%; p = 0.9) and more after 2 months (88 vs. 40%; p = 0.07). However, mean transit rate significantly increased with NUGM, but not UGD (5.0 ± 0.2: 3.6 ± 0.6, p < 0.01). CONCLUSION: Transcutaneous electrical stimulation was beneficial for STC, with response weakly associated with UGD. As measured by NTS, STC children with NUGM responded slightly more, but with significantly greater increased transit compared to those with UGD. Higher numbers are needed to determine if the difference is important.

Evolution of drug resistance during 48 weeks of zidovudine/lamivudine/tenofovir in the absence of real-time viral load monitoring.

OBJECTIVES: To describe the resistance mutations selected by a first-line regimen of zidovudine/lamivudine/tenofovir in the absence of real-time viral load monitoring. DESIGN: A substudy of 300 participants from the Development of Antiretroviral Therapy in Africa trial in Uganda and Zimbabwe, which compared managing antiretroviral therapy with and without laboratory monitoring. METHODS: Stored plasma samples from selected time points were assayed retrospectively for HIV-1 RNA. The pol gene in all baseline samples and those with HIV RNA >1000 copies per milliliter at weeks 24 and 48 were sequenced. RESULTS: The proportion with HIV RNA >1000 copies per milliliter increased from 15% at 24 weeks to 24% at 48 weeks. Eighteen of 31 (58%) genotyped samples at 24 weeks had ≥ 1 major nucleoside reverse transcriptase inhibitor-associated mutations compared with 41 of 47 (87%) at 48 weeks. Excluding 1 nonadherent patient, a mean of 2.0 (95% confidence interval: 1.3 to 2.8) thymidine analogue mutations (TAMs) developed between weeks 24 and 48 among 14 patients with HIV RNA >1000 copies per milliliter at both time points. K65R was detected in 8 of 63 (13%) patients and was negatively associated with number of TAMs (P = 0.01) but not viral subtype (P = 0.30). CONCLUSIONS: A high rate of acquisition of TAMs, but not of K65R, among patients with prolonged viraemia was observed. However, most patients were virologically suppressed at 48 weeks, and long-term clinical and immunological outcomes in the Development of Antiretroviral Therapy in Africa trial were favorable.

A comparison of cervical spine mobilization forces applied by experienced and novice physiotherapists.

STUDY DESIGN: Clinical measurement, cross-sectional. OBJECTIVES: To compare cervical mobilization forces applied by physiotherapists and students, and the factors associated with forces for each group. BACKGROUND: Cervical spine joint mobilization is a common manual technique for treating patients with mechanical neck pain. But little is known about the forces applied during this technique. Potential variability between therapists may result from clinical experience or may be due to factors present in individuals prior to clinical practice exposure. METHODS: One hundred sixteen practicing physiotherapists and 120 physiotherapy students without clinical experience applied grades I through IV posteroanterior mobilization to the premarked C2 and C7 spinous and articular processes of 1 of 67 asymptomatic subjects. An instrumented table recorded applied forces (N), force amplitudes (N), and oscillation frequencies (Hz), and a custom device measured subjects' spinal stiffness (N/mm). Independent t tests were used to compare the forces applied by therapists and students, intraclass correlation coefficients were used to determine variability, and linear regression was used to establish factors associated with applied forces. RESULTS: Students' forces were generally lower (mean difference, 15.7 N for grades III and IV; P<.001) and applied with slower oscillation frequencies (0.12 Hz; P<.001) than therapists' forces. Similar factors were associated with applied forces for both groups: male gender and greater subject body weight were associated with higher applied forces, and greater C2 stiffness with lower forces. Having thumb pain was associated with lower applied forces for therapists but higher ones for students. CONCLUSIONS: Students apply lower forces than therapists. Similar factors appear to affect applied forces regardless of clinical experience.

Cervical spine mobilisation forces applied by physiotherapy students.

OBJECTIVES: Postero-anterior (PA) mobilisation is commonly used in cervical spine treatment and included in physiotherapy curricula. The manual forces that students apply while learning cervical mobilisation are not known. Quantifying these forces informs the development of strategies for learning to apply cervical mobilisation effectively and safely. This study describes the mechanical properties of cervical PA mobilisation techniques applied by students, and investigates factors associated with force application. PARTICIPANTS: Physiotherapy students (n=120) mobilised one of 32 asymptomatic subjects. METHODS: Students applied Grades I to IV central and unilateral PA mobilisation to C2 and C7 of one asymptomatic subject. Manual forces were measured in three directions using an instrumented treatment table. Spinal stiffness of mobilised subjects was measured at C2 and C7 using a device that applied a standard oscillating force while measuring this force and its concurrent displacement. Analysis of variance was used to determine differences between techniques and grades, intraclass correlation coefficients (ICC) were used to calculate the inter- and intrastudent repeatability of forces, and linear regression was used to determine the associations between applied forces and characteristics of students and mobilised subjects. RESULTS: Mobilisation forces increased from Grades I to IV (highest mean peak force, Grade IV C7 central PA technique: 63.7N). Interstudent reliability was poor [ICC(2,1)=0.23, 95% confidence interval (CI) 0.14 to 0.43], but intrastudent repeatability of forces was somewhat better (0.83, 95% CI 0.81 to 0.86). Higher applied force was associated with greater C7 stiffness, increased frequency of thumb pain, male gender of the student or mobilised subject, and a student being earlier in their learning process. Lower forces were associated with greater C2 stiffness. CONCLUSION: This study describes the cervical mobilisation forces applied by students, and the characteristics of the student and mobilised subject associated with these forces. These results form a basis for the development of strategies to provide objective feedback to students learning to apply cervical mobilisation.

Viral rebound and emergence of drug resistance in the absence of viral load testing: a randomized comparison between zidovudine-lamivudine plus Nevirapine and zidovudine-lamivudine plus Abacavir.

BACKGROUND: We investigated virological response and the emergence of resistance in the Nevirapine or Abacavir (NORA) substudy of the Development of Antiretroviral Treatment in Africa (DART) trial. METHODS: Six hundred symptomatic antiretroviral-naive human immunodeficiency virus (HIV)-infected adults (CD4 cell count, <200 cells/mm(3)) from 2 Ugandan centers were randomized to receive zidovudine-lamivudine plus abacavir or nevirapine. Virology was performed retrospectively on stored plasma samples at selected time points. In patients with HIV RNA levels >1000 copies/mL, the residual activity of therapy was calculated as the reduction in HIV RNA level, compared with baseline. RESULTS: Overall, HIV RNA levels were lower in the nevirapine group than in the abacavir group at 24 and 48 weeks (P < .001), although no differences were observed at weeks 4 and 12. Virological responses were similar in the 2 treatment groups for baseline HIV RNA level <100,000 copies/mL. The mean residual activity at week 48 was higher for abacavir in the presence of the typically observed resistance pattern of thymidine analogue mutations (TAMs) and M184V (1.47 log(10) copies/mL) than for nevirapine with M184V and nonnucleoside reverse-transcriptase inhibitor mutations, whether accompanied by TAMs (0.96 log(10) copies/mL) or not (1.18 log(10) copies/mL). CONCLUSIONS: There was more extensive genotypic resistance in both treatment groups than is generally seen in resource-rich settings. However, significant residual activity was observed among patients with virological failure, particularly those receiving zidovudine-lamivudine plus abacavir.

Real-time feedback improves accuracy of manually applied forces during cervical spine mobilisation.

PURPOSE: To determine if real-time feedback enables students to apply mobilisation forces to the cervical spine that are similar to an expert physiotherapist. METHODS: An instrumented treatment table collected mobilisation force data with feedback about forces displayed on a computer screen. An expert physiotherapist performed posteroanterior mobilisation of C7 on 21 asymptomatic subjects while forces were recorded. These data were used as force targets for 51 students who mobilised one of the asymptomatic subjects on two occasions. Students' forces were recorded before and after practice either with (experimental group) or without real-time feedback (control group). Improved performance was defined as a smaller difference between expert and student forces, comparing groups with non-parametric statistics. RESULTS: Students receiving feedback applied more accurate forces than controls (median difference between student and expert forces in the experimental group, 4.0N, inter-quartile range (IQR) 1.9-7.7; in controls, 14.3N, IQR 6.2-26.2, difference between groups p<0.001). One week later, these students still applied forces that more closely matched the expert's compared to controls (p<0.01), but the differences between the students' and expert's forces were greater (6.4N, IQR 3.1-14.7). CONCLUSION: Practice with real-time objective feedback enables students to apply forces similar to an expert, supporting its use in manual therapy training.

Daily transabdominal electrical stimulation at home increased defecation in children with slow-transit constipation: a pilot study.

PURPOSE: Transcutaneous electrical stimulation (TES) (3 sessions/wk) over the abdomen stimulated bowel functions in a randomized controlled trial. This pilot study assessed whether daily TES at home with a safe, portable machine would be possible and more efficacious than trial results. METHODS: Eleven patients (6 male/5 female; mean age, 14 years; range, 12-18 years) with slow-transit constipation who relapsed or responded poorly in the trial were recruited (11 +/- 5 months later). An EPM-IF-4160 (Fuji Dynamics, Hong Kong) portable machine (sine waveform, 4 kHz carrier frequency, 80-160 Hz beat frequency, intensity <33 mA) delivering interferential current (2 electrodes over epigastrium + 2 over kidneys) was applied 1 hour daily at home. Continence diaries were kept for 1 month before and 2 months during treatment. RESULTS: All children completed more than 1 month of treatment after baseline recording. Defecation increased in 9 of 11 children, and soiling decreased in 4 of 11 children. There was a significant increase in total episodes of defecation per week (mean +/- SD, 2.5 +/- 2.1 vs 6.7 +/- 4.4; P = .008) and a nonsignificant decrease in soiling (3.8 +/- 1.6 vs 1.1 +/- 0.5 episodes/wk, P = .1). Daily stimulation does not affect abdominal pain. No adverse events occurred. CONCLUSIONS: Daily TES at home is safe and significantly improved bowel function in children who did not respond to 3 times per week of TES. Home TES may be a novel treatment of intractable slow transit constipation, avoiding hospital visits.

Trunk strength and mobility changes in children with slow transit constipation.

BACKGROUND AND AIM: It appears that there are no published reports on childhood slow transit constipation (STC) that have considered the state of the musculoskeletal components of the trunk in these children. The present study aimed to determine whether children with STC have different trunk musculoskeletal characteristics that might be related to their defecation difficulties, compared to controls. METHODS: With the aid of computer-analyzed photographs and clinical testing, 41 children with STC and 41 age-matched controls were examined for Marfanoid features, sitting posture, spinal joint mobility and trunk muscle strength. The latter was assessed by measuring maximum voluntary abdominal bulging and retraction in sitting, and active trunk extension in prone-lying. Levels of general exercise and sedentary activities were evaluated by questionnaire. RESULTS: STC subjects were more slumped in relaxed sitting (P < or = 0.001), less able to bulge (P < or = 0.03) and less able to actively extend the trunk (P = 0.02) compared to controls. All subjects sat more erect during abdominal bulging (P < or = 0.03). CONCLUSION: The results show that STC children have reduced trunk control and posture, which indicates that clinicians should include training of trunk muscles and correction of sitting posture. There was no evidence that children with STC exercised less than the controls.

Slow-transit constipation in children: our experience.

Constipation is a common problem in children, with childhood prevalence estimated at between 1 and 30%. It accounts for a significant percentage of referrals to paediatricians and paediatric gastroenterologists. It commonly runs in families, suggesting either an underlying genetic predisposition or common environmental factors, such as dietary exposure. The peak age for presentation of constipation is shortly after toilet training, when passage of hard stools can cause pain on defecation, which then triggers holding-on behaviour in the child. At the time of the next call to stool the toddler may try to prevent defecation by contraction of the pelvic floor muscles and anal sphincter. Unless the holding-on behaviour is quickly corrected by interventions to soften faeces and prevent further pain, the constipation can very rapidly become severe and chronic. Until recently, this mechanism was thought to be the only significant primary cause of constipation in childhood. In this review, we will summarise recent evidence to suggest that severe chronic constipation in children may also be due to slowed colonic transit.

Decreased colonic transit time after transcutaneous interferential electrical stimulation in children with slow transit constipation.

PURPOSE: Idiopathic slow transit constipation (STC) describes a clinical syndrome characterised by intractable constipation. It is diagnosed by demonstrating delayed colonic transit on nuclear transit studies (NTS). A possible new treatment is interferential therapy (IFT), which is a form of electrical stimulation that involves the transcutaneous application of electrical current. This study aimed to ascertain the effect of IFT on colonic transit time. METHODS: Children with STC diagnosed by NTS were randomised to receive either 12 real or placebo IFT sessions for a 4-week period. After a 2-month break, they all received 12 real IFT sessions-again for a 4-week period. A NTS was repeated 6 to 8 weeks after cessation of each treatment period where able. Geometric centres (GCs) of activity were calculated for all studies at 6, 24, 30, and 48 hours. Pretreatment and posttreatment GCs were compared by statistical parametric analysis (paired t test). RESULTS: Thirty-one pretreatment, 22 postreal IFT, and 8 postplacebo IFT studies were identified in 26 children (mean age, 12.7 years; 16 male). Colonic transit was significantly faster in children given real treatment when compared to their pretreatment NTS at 24 (mean CG, 2.39 vs 3.04; P < or = .0001), 30 (mean GC, 2.79 vs 3.47; P = .0039), and 48 (mean GC, 3.34 vs 4.32; P = .0001) hours. By contrast, those children who received placebo IFT had no significant change in colonic transit. CONCLUSIONS: Transcutaneous electrical stimulation with interferential therapy can significantly speed up colonic transit in children with slow transit constipation.

Forces applied to the cervical spine during posteroanterior mobilization.

OBJECTIVE: There is little information on manual forces applied during cervical mobilization, a common treatment technique. Potential variability of applied forces between therapists and treatment occasions, and factors associated with different force applications are unknown. The purpose of this study is to establish the baseline mechanical properties of cervical spine mobilization and to determine if the applied forces are affected by the characteristics of therapists and mobilized subjects. METHODS: Physiotherapists (n = 116) applied 4 grades of posteroanterior mobilization to the premarked C2 and C7 spinous (central technique) and articular processes (unilateral technique, one right and one left) of 1 of 35 asymptomatic subjects. Techniques were performed in randomized order, and the first one was repeated after 20 minutes. Load cells attached to the treatment table recorded forces in 3 directions. Before mobilization, subjects' spinal stiffness at the C2 and C7 spinous processes was measured using a custom device. Analyses of variance with Bonferroni post hoc tests determined technique and grade differences, intraclass correlation coefficients the reliability between therapists, and linear regression the factors associated with forces. RESULTS: Therapists apply distinct manual forces for different techniques and grades (P < .001). Variability between therapists is high, but intratherapist reliability is good (intraclass correlation coefficient [2,1] for different force parameters, 0.84-0.93). Mean peak forces increase from grades I to IV, ranging from 22 to 92 N for resultant forces. Greater vertical and caudad-cephalad forces are applied to C7 than C2 (P < .01), with higher mediolateral forces during unilateral techniques (P < .001). Male sex of the therapist or the mobilized subject is associated with higher forces, and C2 stiffness, thumb pain and postgraduate training with lower (P < .05). CONCLUSIONS: These results quantify cervical mobilization forces, which will inform future research aimed at improving its application and clinical effectiveness.

Measuring the posteroanterior stiffness of the cervical spine.

An essential part of improving manual therapy treatment for cervical spine disorders is the identification of the mechanical effects of manual techniques. The aims of this research were to develop a reliable and safe instrument for measuring cervical spine stiffness, and to document stiffness in a group of asymptomatic individuals. A device for measuring cervical spine stiffness was designed and tested. The stiffness of the cervical spine of 67 asymptomatic individuals was measured at C2 and C7 on one or more occasions. Stiffness was defined as the slope of the linear region of the force-displacement curve (coefficient K). For C2, the linear region of the force-displacement curve was from 7 to 40 N, and for C7, 20-70 N. The mean stiffness (coefficient K) on the first measurement occasion at C2 was 4.58 N/mm (95% CI 4.30-4.85), and at C7 was 7.03 N/mm (95% CI 6.50-7.57). ICC(2,1) for repeated measurements was 0.84 (95% CI 0.74-0.90). Stiffness measurements in the cervical spine were generally lower than those previously reported for the lumbar spine. Age was positively associated with C2 stiffness (p=0.01). Males were stiffer at C7 than females (p<0.001). This research provides a basis for future studies investigating the effects of manual techniques on cervical spine stiffness, potentially leading to improved outcomes for patients treated by manual therapy.

Calibration of an instrumented treatment table for measuring manual therapy forces applied to the cervical spine.

Manual therapy techniques are commonly used to treat musculoskeletal neck disorders, but little is known about the manual forces applied during cervical spine treatment. Forces may vary between practitioners, and this may affect patient outcomes. This study reports the development of an instrumented treatment table and its calibration for measuring posteroanterior-directed forces applied during cervical spine mobilisation. A treatment table surface was instrumented with seven biaxial load cells to measure manually applied forces in three planes. Accuracy of the system was evaluated using known weights (unloaded and loaded to represent a patient's body weight), selected to be consistent with the level of forces expected to be applied during cervical mobilisation. Recorded force values strongly correlated with known weights (Pearson's r=0.999 to 1.000 for forces applied in different directions and locations, unloaded and loaded). The accuracy of forces in the unloaded condition was very good for vertical forces (mean absolute error 1.1N, SD 1.5), and reasonably good for horizontal forces (2.8N, SD 2.4 for mediolateral, 3.4N, SD 1.5 for caudad-cephalad). In the loaded condition absolute error increased slightly for horizontal forces. The accuracy of measured forces indicates the instrumented table is acceptable for measuring cervical mobilisation forces. Using it allows practitioners to perform manual techniques using their usual clinical technique, however interpretation of force data is limited because it represents force applied to the table rather than at a specific joint.