The impact of being overweight or obese on 12 month clinical recovery in patients following lumbar microdiscectomy for radiculopathy

BACKGROUND CONTEXT

The proportion of patients who undergo lumbar microdiscectomy due to lumbar radiculopathy who are also overweight or obese is high. However, whether high body mass index (BMI) affects clinical outcomes is not well-studied.

PURPOSE

To investigate the difference in the clinical course between normal weight, overweight, and obese patients with radiculopathy who underwent lumbar microdiscectomy followed by physical therapy and to evaluate whether high BMI is associated with poor recovery.

STUDY DESIGN/SETTING

A prospective cohort study with a 12-month follow-up was conducted in a multidisciplinary clinic.

PATIENT SAMPLE

We included 583 patients (median [IQR] age: 45 [35-52] years; 41% female) with clinical signs and symptoms of lumbar radiculopathy, consistent with magnetic resonance imaging findings, who underwent microdiscectomy followed by postoperative physical therapy.

OUTCOME MEASURES

Outcomes were leg pain and back pain intensity measured with a visual analogue scale, disability measured with the Roland Morris Disability Questionnaire at 3 and 12-month follow-ups, and complications.

METHODS

Patients were classified as being normal weight (46.9%), overweight (38.4%), or obese (14.7%). A linear mixed-effects model was used to assess the difference in the clinical course of pain and disability between the three BMI categories. The association between BMI and outcomes was evaluated using univariable and multivariable logistic regression analyses.

RESULTS

All three patient groups experienced a significant improvement in leg pain, back pain, and disability over 3 and 12-month follow-up. Patients who were overweight, obese, or normal weight experienced comparable leg pain (p=.14) and disability (p=.06) over the clinical course (p=.14); however, obese patients experienced higher back pain (MD=-6.81 [95%CI: -13.50 to -0.14]; p=.03). The difference in back pain scores was not clinically relevant.

CONCLUSIONS

In the first year following lumbar microdiscectomy, patients demonstrated clinical improvements and complications that were unrelated to their preoperative BMI.

Variability in recovery following microdiscectomy and postoperative physiotherapy for lumbar radiculopathy: A latent class trajectory analysis

OBJECTIVES

The clinical course of lumbar radiculopathy following microdiscectomy and post-operative physiotherapy varies substantially. No prior studies assessed this variability by deriving outcome trajectories. The primary aims of this study were to evaluate the variability in long-term recovery after lumbar microdiscectomy followed by post-operative physiotherapy and to identify outcome trajectories. The secondary aim was to assess whether demographic, clinical characteristics and patient-reported outcome measures routinely collected at baseline could predict poor outcome trajectories.

METHODS

We conducted a prospective cohort study with a 24-month follow-up. We included 479 patients with clinical signs and symptoms of lumbar radiculopathy confirmed by Magnetic Resonance Imaging findings, who underwent microdiscectomy and post-operative physiotherapy. Outcomes were leg pain and back pain measured with Visual Analogue Scales, and disability measured with the Roland-Morris Disability Questionnaire. Descriptive statistics were performed to present the average and the individual clinical course. A latent class trajectory analysis was conducted to identify leg pain, back pain, and disability outcome trajectories. The best number of clusters was determined using the Bayesian Information Criterion, Akaike's information criteria, entropy, and overall interpretability. Prediction models for poor outcome trajectories were assessed using multivariable logistic regression analyses.

RESULTS

Several outcome trajectories were identified. Most patients were assigned to the 'large improvement' trajectory (leg pain: 79.3%; back pain: 70.2%; disability: 59.5% of patients). Smaller proportions of patients were assigned to the 'moderate improvement' trajectory (leg pain: 7.9%; back pain: 10.6%; disability: 20.7% of patients), the 'minimal improvement' trajectory (leg pain: 4.9%, back pain: 6.7%, disability: 16.3% of patients) and the 'relapse' trajectory (leg pain: 7.9%; back pain: 12.5%; disability: 3.5%). Approximately one-third of patients (32.6%) belonged to one or more than one poor outcome trajectory. Patients with previous treatment (prior back surgery, injection therapy, and medication use) and those who had higher baseline pain and disability scores were more likely to belong to the poor outcome trajectories in comparison to the large improvement trajectories in back pain, leg pain and disability, and the moderate improvement trajectory in disability. The explained variance (Nagelkerke R2) of the prediction models ranged from 0.06 to 0.13 and the discriminative ability (Area Under the Curve) from 0.66 to 0.73.

CONCLUSION

The clinical course of lumbar radiculopathy varied following microdiscectomy and post-operative physiotherapy, and several outcome trajectories could be identified. Although most patients were allocated to favorable trajectories, one in three patients was assigned to one or more poor outcome trajectories following microdiscectomy and post-operative physiotherapy for lumbar radiculopathy. Routinely gathered data were unable to predict the poor outcome trajectories accurately. Prior to surgery, clinicians should discuss the high variability and the distinctive subgroups that are present in the clinical course with their patients.

A Clinical Journey Mobile Health App for Perioperative Patients: Cross-sectional Study

Background

Mobile eHealth apps are important tools in personal health care management. The Patient Journey app was developed to inform patients with musculoskeletal disorders during their perioperative period. The app contains timely information, video exercises, and functional tasks. Although the Patient Journey app and other health apps are widely used, little research is available on how patients appreciate these apps.

Objective

The primary aim of this study was to evaluate the user-friendliness of the Patient Journey app in terms of its usability and the attitudes of users toward the app. The secondary aim was to evaluate positive and negative user experiences.

Methods

A web-based questionnaire was sent to 2114 patients scheduled for surgery for a musculoskeletal disorder. Primary outcomes were usability (measured with the System Usability Scale) and user attitudes regarding the Patient Journey app (assessed with the second part of the eHealth Impact Questionnaire). The secondary outcomes were evaluated with multiple choice questions and open-ended questions, which were analyzed via inductive thematic content analyses.

Results

Of the 940 patients who responded, 526 used the Patient Journey app. The usability of the app was high (System Usability Scale: median 85.0, IQR 72.5-92.5), and users had a positive attitude toward the Information and Presentation provided via the app (eHealth Impact Questionnaire: median 78.0, IQR 68.8-84.4). The app did not adequately improve the users’ confidence in discussing health with others (eHealth Impact Questionnaire: median 63.9, IQR 50.0-75.0) or motivation to manage health (eHealth Impact Questionnaire: median 61.1, IQR 55.6-72.2). Three core themes emerged regarding positive and negative user experiences: (1) content and information, (2) expectations and experiences, and (3) technical performance. Users experienced timely information and instructions positively and found that the app prepared and guided them optimally through the perioperative period. Negative user experiences were overly optimistic information, scarcely presented information about pain (medication), lack of reference data, insufficient information regarding clinical course deviations and complications, and lack of interaction with clinicians.

Conclusions

The Patient Journey app is a usable, informative, and presentable tool to inform patients with musculoskeletal disorders during their perioperative period. The qualitative analyses identified aspects that can further improve the user experiences of the app.

The diagnostic accuracy and test-retest reliability of the Dutch PainDETECT and the DN4 screening tools for neuropathic pain in patients with suspected cervical or lumbar radiculopathy

BACKGROUND

It is important to identify neuropathic pain early to guide treatment decisions and prevent chronicity. There is lack of evidence whether the Dutch painDETECT questionnaire and Douleure Neuropathique en 4 questions (DN4) can adequately assess neuropathic pain.

METHODS

Patients suspected of cervical or lumbar radiculopathy were eligible for inclusion. The Dutch painDETECT and DN4 were considered as the index tests and were compared to the reference test consisting of the consensus expert diagnosis by using the grading system for neuropathic pain. The index tests and neuropathic pain diagnosis were blindly performed. Diagnostic accuracy was determined by calculating sensitivity, specificity, predictive values and likely hood ratios. Test-retest reliability for the index tests was assessed using Intraclass Correlation Coefficients (ICC).

RESULTS

A total of 180 patients were included, of which 110 for the reliability analysis. Fifty-nine patients (33%) had neuropathic pain according to the reference test. Both the painDETECT and DN4 had moderate sensitivity of respectively 75% (95% CI: 61.6-85.0) and 76% (95% CI: 63.4-86.4) and poor specificity of respectively 51% (95% CI: 42.0-60.4) and 42% (95% CI: 33.2-51.5). Combining negative test results for both screening tools increased the sensitivity up to 83% (95% CI: 71.0-91.6). The ICC for the painDETECT was 0.91 (95% CI: 0.86-0.94) and for the DN4 0.86 (95% CI: 0.80-0.91).

CONCLUSIONS

The use of the Dutch painDETECT and the DN4 in patients with suspected radiculopathy should not be recommended yet. A combination of both screening tools seems most suitable to rule out neuropathic pain in patients suspected of radiculopathy.

LEVEL OF EVIDENCE

Diagnosis, Level 1B.

Effectiveness of the 2009 seasonal influenza vaccine against pandemic influenza A(H1N1)2009 in healthcare workers in New Zealand, June-August 2009

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Effectiveness of the 2009 seasonal influenza vaccine against pandemic influenza A(H1N1)2009 in healthcare workers in New Zealand, June-August 2009

There is uncertainty whether the 2009 seasonal influenza vaccination influences the risk of infection with the 2009 pandemic influenza A(H1N1) virus. This issue was investigated in 548 healthcare workers from Capital and Coast District Health Board, Wellington, New Zealand, presenting with influenza-like illness during the influenza pandemic between June and August 2009. All workers completed an assessment sheet and had a nasopharyngeal swab tested by real-time RT-PCR. The risk of pandemic influenza A(H1N1) infection associated with the 2009 seasonal inactivated trivalent influenza vaccine was determined by logistic regression, with adjustment for potential confounding variables. In 96 workers pandemic influenza A(H1N1) RNA was detected and 452 tested negative. The multivariate analysis did not show any effect of vaccination on PCR-confirmed influenza A(H1N1)2009 infection (odds ratio 1.2, 95% confidence interval 0.7–1.9, p=0.48). We conclude that 2009 seasonal influenza vaccination had no protective effect against influenza A(H1N1)2009 infection amongst healthcare workers. To protect against further waves of the current pandemic influenza or future pandemics in which the influenza virus is antigenically distinct from contemporary seasonal influenza viruses, it would be necessary to vaccinate with a specific pandemic influenza vaccine, or a seasonal influenza vaccine that includes the pandemic influenza serotype.

Spatiotemporal pattern of neuroinflammation after impact-acceleration closed head injury in the rat

Inflammatory processes have been implicated in the pathogenesis of traumatic brain damage. We analyzed the spatiotemporal expression pattern of the proinflammatory key molecules: interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, and inducible nitric oxide synthase in a rat closed head injury (CHI) paradigm. 51 rats were used for RT-PCR analysis after CHI, and 18 for immunocytochemistry. We found an early upregulation of IL-1beta, IL-6, and TNF-alpha mRNA between 1h and 7h after injury; the expression of iNOS mRNA only revealed a significant increase at 4h. After 24h, the expression decreased towards baseline levels, and remained low until 7d after injury. Immunocytochemically, IL-1beta induction was localized to ramified microglia in areas surrounding the primary impact place as well as deeper brain structures. Our study shows rapid induction of inflammatory gene expression that exceeds by far the primary impact site and might therefore contribute to tissue damage at remote sites.

A role for the cerebellum in motor speech planning: Evidence from foreign accent syndrome

A 3 year follow-up study was performed in a patient with foreign accent syndrome (FAS) as the sole cognitive manifestation of a left fronto-parietal stroke. The hypothesis of involvement of the right cerebellum in this motor speech planning disorder was investigated by means of functional neuroimaging (SPECT) and neurobehavioral assessments. Based on the close parallelism between the evolution of FAS symptoms and the perfusional changes in the right cerebellum, it is argued that FAS may result from a disruption of a close functional interplay between the supra- and infratentorial speech centers involved in motor speech planning.

Central nervous system metastases of pulmonary adenocarcinoma mimicking neurofibromatosis type 2

We report a case of a 51-year-old man presenting with rapidly progressive unilateral tinnitus, hearing loss and imbalance. Neuroimaging revealed bilateral VIIIth cranial nerve masses and multiple cerebral and spinal cord lesions that were interpreted as being acoustic schwannomas and multiple meningeomas. An initial tentative diagnosis of neurofibromatosis type 2 (NF2) was made. Both clinical and radiological evolution were atypical for NF2 and the initial diagnosis of NF2 was questioned. Additional technical investigations demonstrated a pulmonary adenocarcinoma. Postmortem examination confirmed that this patient had multiple central nervous system metastases of a primary pulmonary adenocarcinoma, presenting clinically and neuroradiologically as a probable neurofibromatosis type 2. Clinicians should be aware of the rare possibility of central nervous system metastases mimicking NF2.

Pentobarbital fails to reduce cerebral oxygen consumption early after non-hemorrhagic closed head injury in rats

It is unknown whether barbiturates suppress cerebral oxygen metabolism after cerebral trauma as they do in normal individuals. We evaluated the influence of pentobarbital on cerebral oxygen handling of normal rats and rats subjected to non-hemorrhagic closed head injury (CHI). Oxygen delivery was assessed by measuring cerebral perfusion and oxygen extraction, enabling the calculation of cerebral metabolic rate of oxygen (CMRO2). Mitochondrial function was assessed by studying changes in the oxidized cytochrome oxidase concentration. CHI caused changes in both systemic and cerebral hemodynamics. Cerebral blood flow was reduced to 66% of its control value, but the cerebral metabolic rate of oxygen remained unchanged. Pentobarbital administration induced a significant lowering of the cerebral oxygen consumption in normal rats associated with a secondary decrease in cerebral perfusion. In rats subjected to CHI, pentobarbital was unable to lower the cerebral metabolic demand and did not cause a further decrease in perfusion. Pentobarbital was unable to significantly modulate mitochondrial function in traumatized rats, whereas it exerted this effect in all control animals. We therefore conclude that, in rats subjected to CHI, pentobarbital is unable to perform its beneficial effects on the cerebral metabolism.

Continuous measurement of intracranial pressure in awake rats after experimental closed head injury

The present study validates a method for continuous measurement of intracranial pressure (ICP) in freely moving rats after experimental induction of impact-acceleration injury. Rats subjected to either mild or moderate trauma were individually placed in a Bas-Ratturn system, equipped with a sensor that synchronously turns the cage in response to the locomotor activity of the animal. In this way correct probe positioning is permanently assured and damage due to coiling is avoided. The evolution of ICP and mean arterial blood pressure (MABP) in injured rats was compared with that of a non-traumatized sham group. Since the animals regained consciousness after surgery, interference of anaesthesia on these sensitive parameters should be minimised. The results showed that immediately after induction of neurotrauma, ICP was significantly higher in traumatized rats (sham: 7.7 +/- 0.5 mmHg; mild trauma: 10.4 +/- 0.7 mmHg; moderate trauma: 14.9 +/- 2.4 mmHg; P<0.05). Regression analysis showed a stable ICP up to 3 h post-insult for all three conditions. From 4 h onwards till the end of the experiment at 10 h post-insult, a significant increase in ICP was seen for sham-operated and mildly traumatized rats (16.1 +/- 3.4 and 30.5 +/- 6.9 mmHg, respectively; P<0.05), but not for moderately traumatized rats (47.3 +/- 11.9 mmHg). The method allows observation of ICP for a critical period up to 3 h. As such the method can be regarded as clinically relevant to study early pathological aspects of intracranial hypertension and to define a therapeutic window for pharmacological intervention after traumatic brain injury (TBI).

Ultrasound agents may open the blood-brain barrier in rats and aggravate pathologic consequences of experimental head trauma

Unilateral intracarotid injection of contrast agents may considerably destabilize the blood-brain barrier in rats. This leads to vasogenic edema in the ipsilateral hemisphere. Mortality and extravasation increased significantly when administration of these ultrasound contrast agents was followed by mild traumatic brain injury. Direct administration to the cerebral circulation is, therefore, indicative for edema-related pathology and may amplify the consequences of experimental neurotrauma.

Comparison of intracranial pressure measured in the cerebral cortex and the cerebellum of the rat

In this study, we evaluated the accuracy of intracranial pressure (ICP) measurement in rats by insertion of a miniature ICP probe in the parenchyma of the cerebellum. A comparison was made between the ICP values measured simultaneously in the parenchyma of the cerebral cortex and the cerebellum. In order to obtain a wide range of ICP, animals were subjected to a severe closed head injury (CHI), a moderate CHI or to a sham operation. ICP values ranged from 0.8 to 43.9 mmHg. After 15 min stabilisation the first measurement was taken and followed by a second measurement 25 min after onset to allow comparison of ICP changes at the two implantation sites. Linear regression analysis showed a highly significant correlation at 15 min: Y = 0.919X + 0.655 (R(2) = 0.977), and at 25 min: Y = 0.931X + 0.698 (R(2) = 0.976). The differences in ICP measurement between cerebellar and cerebral site were not significantly different from zero at both time points. Altman-Bland plots showed that the difference in ICP readings between the two locations could differ maximally by 5.3 mmHg. The largest differences were detected when high ICP values were recorded. We conclude that in rats the ICP measurement in the cerebellum is comparable to the ICP measurement in the cerebral cortex. The cerebellar ICP can be used as a valuable alternative during experimental procedures.

Current outcome in patients with lung cancer and positive mediastinoscopy

PURPOSE

A retrospective study was undertaken to determine the contemporary treatment and outcome of patients with lung cancer and positive lymph nodes proven at mediastinoscopy.

MATERIAL AND METHODS

From 1994 to 1999 a cervical mediastinoscopy was performed in 361 patients. Metastatic lymph nodes from a bronchogenic carcinoma were present in 81 patients; 71 were men. Mean age was 61.7 years. Squamous cell carcinoma and adenocarcinoma were present in 26 patients each (32.1%), large cell carcinoma in 19 patients (23.4%), small cell carcinoma in six patients (7.4%) and other histologies in four patients (5%). Stage IIIA was found in 51 patients (69.9%), IIIB in 17 (23.3%) and IV in 5 (6.8%). Of eight patients no precise stage could be determined (9.9%). These patients were retrospectively reviewed. Survival time was analyzed according to the Kaplan-Meier method. A multivariate Cox analysis was performed to determine significant factors in relation to survival.

RESULTS

Forty-four patients (54.3%) were treated by induction chemotherapy, of which 15 were operated on, 11 patients (13.6%) had chemotherapy only, 11 (13.6%) radiotherapy only, 3 (3.7%) combined chemo- and radiotherapy, 1 patient (1.2%) had an operation only, and 11 (13.6%) received palliative treatment. Follow-up was complete; 16 patients (19.8%) are alive and 65 (80.2%) died, mostly of local recurrence and metastases. Median survival time (MST) for all 81 patients was 12 months [95% confidence interval (CI) 10-14 months.]. MST for the 15 patients treated by induction chemotherapy + surgery was 27 months [95% CI 18-36 months] and for the 15 patients treated by induction chemotherapy + radiotherapy 15 months [95% CI 12-18 months]. The difference between these two subgroups was significant (p = 0.03). For the 11 patients who had palliative treatment MST was 6 months [95% CI 4-8 months]. The other subgroups had a MST of 10 months or less. In a multivariate Cox analysis only specific treatment (p = 0.0002) and stage (p = 0.02) were found to be significant.

CONCLUSIONS

Outcome of patients with lung cancer and positive mediastinoscopy remains poor. In this retrospective study best results were obtained by induction chemotherapy + surgery. An effort should be made to include as many of these patients as possible in neoadjuvant trials.

Coamplification of esterase A and B genes as a single unit in Culex pipiens mosquitoes

In Culex pipiens mosquitoes, resistance to organophosphorous insecticides often results from increased detoxification by two types of esterases, A and B, which are closely linked. Overproduction of all esterase B so far investigated (B1, B2, B4, B5 and B6) is from gene amplification. An esterase A gene (esterase A2) has recently been cloned from mosquitoes with the overproduced esterases A2 and B2, and amplification of this gene has also been reported. We describe the cDNA sequences of three additional esterase genes from insecticide-resistant strains of Culex pipiens originating from France and California which show at least 93 per cent homology with the esterase A2 gene sequence. Restriction enzyme mapping shows that the esterase A gene lies within 2.2 kb of the esterase B gene. In mosquitoes with overproduced esterases A2 and B2, the amplification level of esterase A is equal to that of esterase B suggesting that the genes are coamplified. Furthermore, we show that in one strain with an overproduced A esterase (A1), gene amplification cannot account for the increased protein level. This indicates that overproduction of esterases A can be achieved through two different mechanisms: gene amplification and a regulatory mechanism--the nature of which remains to be identified.

Testing the unique amplification event and the worldwide migration hypothesis of insecticide resistance genes with sequence data

In the mosquito Culex pipiens, over-production of esterases is a common insecticide resistance mechanism. Different alleles at the esterase A and B loci are known to occur in natural populations, as shown by enzyme electrophoresis and RFLP studies on the esterase B locus. Here we analyse the variability of the esterase A locus at the nucleotide level in mosquitoes possessing or lacking over-produced esterase A. A surprisingly high level of nucleotide polymorphism is found in coding and noncoding regions, and the extent of polymorphism detected is higher than that previously described for the most polymorphic loci in Drosophila. We also show that eight strains from different localities (Africa, America, Asia) that possess the over-produced esterase A2 share the same nucleotide sequence at the esterase A locus, strongly supporting the evolutionary scenario of a unique event of amplification of this gene followed by dispersal through migration rather than the occurrence of multiple independent mutational events of the gene.