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Dive into the research topics where Johan Theron is active.

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Featured researches published by Johan Theron.


Respiration | 2005

Utility of Rapid On-Site Evaluation of Transbronchial Needle Aspirates

Andreas H. Diacon; Macé M. Schuurmans; Johan Theron; Mercia Louw; Colleen A. Wright; Karen Brundyn; Chris T. Bolliger

Background: Rapid on-site evaluation has been proposed as a method to improve the yield of transbronchial needle aspiration. Objectives: This study investigated whether on-site analysis facilitates routine diagnostic bronchoscopy in terms of sampling, yield and cost. Methods: Patients with lesions accessible for transbronchial needle aspiration on computed tomography were investigated. A cytopathologist screened the needle aspirates on site for the presence of diagnostic material. The bronchoscopic sampling process was adjusted according to the results. In 90 consecutive patients with neoplastic disease (n = 70; 78%), non-neoplastic disease (n = 16; 18%) or undiagnosed lesions (n = 4; 4%) we aspirated 162 lung lesions (paratracheal tumours or lymph nodes: 7%; tracheobronchial lymph nodes: 68%; other: 25%). Results: The diagnostic yield of needle aspiration was 77 and 25% in patients with neoplastic and non-neoplastic lesions, respectively. Sampling could be terminated in 64% of patients after needle aspiration had been performed as the only diagnostic modality, and on-site analysis identified diagnostic material from the first site aspirated in 50% of patients. Only in 2 patients (2%) diagnostic aspirates were not recognized on site. On-site analysis was cost effective due to savings for disposable diagnostic tools, which exceeded the extra expense for the on-site cytology service provided. Conclusions: Rapid on-site analysis of transbronchial aspirates is a highly useful, accurate and cost-effective addition to routine diagnostic bronchoscopy.


Respiration | 2004

Safety and yield of ultrasound-assisted transthoracic biopsy performed by pulmonologists

Andreas H. Diacon; Macé M. Schuurmans; Johan Theron; Pawel Schubert; Colleen A. Wright; Chris T. Bolliger

Background: Transthoracic ultrasound (US) has gained popularity as a tool for visualizing pleural effusions and assisting thoracentesis or chest drain placement. In the absence of effusion, US just as well demonstrates solid masses involving or abutting the pleura, yet biopsy of such lesions is not widely performed by chest physicians. Objective: To assess the feasibility and the safety of US-assisted cutting needle biopsy performed by chest physicians in routine practice. Methods: Lesions involving or abutting the pleura ≧20 mm in diameter on US were sampled with a 14-gauge cutting needle under local anesthesia. Biopsy site, needle direction and depth of penetration were determined with US. The procedure was performed without direct US guidance in ‘free-hand’ technique. Results: Ninety-one patients underwent 96 cutting-needle biopsies for suspected peripheral lung tumors (n = 44, 46%), pleural-based (n = 39, 41%), mediastinal (n = 10, 10%), or chest wall lesions (n = 3, 3%), which were single in 71%, multiple in 6% and diffuse in 23%. Sensitivity for malignant neoplasms (n = 65) was 85.5% and 100% for mesothelioma (n = 10). Pneumothorax occurred in 4%. Conclusions: US-assisted cutting-needle biopsy of lesions ≧20 mm in diameter is safe in the hands of pulmonologists. The yield for neoplastic disease including mesothelioma is high.


Thorax | 2010

Direct comparison of the diagnostic yield of ultrasound-assisted Abrams and Tru-Cut needle biopsies for pleural tuberculosis

Coenraad F.N. Koegelenberg; Christoph Thomas Bolliger; Johan Theron; Gerhard Walzl; Colleen A. Wright; Mercia Louw; Andreas H. Diacon

Background Tuberculous pleuritis remains the commonest cause of exudative effusions in areas with a high prevalence of tuberculosis and histological and/or microbiological confirmation on pleural tissue is the gold standard for its diagnosis. Uncertainty remains regarding the choice of closed pleural biopsy needles. Objectives This prospective study compared ultrasound-assisted Abrams and Tru-Cut needle biopsies with regard to their diagnostic yield for pleural tuberculosis. Methods 89 patients (54 men) of mean±SD age 38.7±16.7 years with pleural effusions and a clinical suspicion of tuberculosis were enrolled in the study. Transthoracic ultrasound was performed on all patients, who were then randomly assigned to undergo ≥4 Abrams needle biopsies followed by ≥4 Tru-Cut needle biopsies or vice versa. Medical thoracoscopy was performed on cases with non-diagnostic closed biopsies. Histological and/or microbiological proof of tuberculosis on any pleural specimen was considered the gold standard for pleural tuberculosis. Results Pleural tuberculosis was diagnosed in 66 patients, alternative diagnoses were established in 20 patients and 3 remained undiagnosed. Pleural biopsy specimens obtained with Abrams needles contained pleural tissue in 81 patients (91.0%) and were diagnostic for tuberculosis in 54 patients (sensitivity 81.8%), whereas Tru-Cut needle biopsy specimens only contained pleural tissue in 70 patients (78.7%, p=0.015) and were diagnostic in 43 patients (sensitivity 65.2%, p=0.022). Conclusions Ultrasound-assisted pleural biopsies performed with an Abrams needle are more likely to contain pleura and have a significantly higher diagnostic sensitivity for pleural tuberculosis.


European Respiratory Journal | 2006

Transbronchial needle aspirates: how many passes per target site?

Andreas H. Diacon; Macé M. Schuurmans; Johan Theron; Karen Brundyn; Mercia Louw; Colleen A. Wright; Chris T. Bolliger

Transbronchial needle aspiration is a bronchoscopic sampling method for a variety of bronchial and pulmonary lesions. The present study investigated whether and how serial needle passes contribute to the yield of transbronchial needle aspiration at specific target sites. A total of 1,562 needle passes, performed at 374 target sites in 245 patients with neoplastic disease (82%), non-neoplastic disease (15%) or undiagnosed lesions (3%), were prospectively recorded and rated for anatomical location, size, bronchoscopic appearance and underlying disease. Positive aspirates were obtained in 75% of patients and at 68% of target sites. A diagnosis was established with the first, second, third and fourth needle pass at 64, 87, 95 and 98% of targets, respectively. The absolute yield varied strongly with target site features, but the stepwise increment to the maximum yield provided by serial passes was similar across target sites. In conclusion, three transbronchial needle passes per site are appropriate when only a tissue diagnosis is sought and when alternative sites or sampling modalities are available. At least four or five passes should be carried out at lymph node stations critical for the staging of lung cancer.


European Respiratory Journal | 2006

Ultrasound-assisted transthoracic biopsy: fine-needle aspiration or cutting-needle biopsy?

Andreas H. Diacon; Johan Theron; Pawel T. Schubert; Karen Brundyn; Mercia Louw; Colleen A. Wright; Chris T. Bolliger

The present study compared the diagnostic yield of ultrasound-assisted cutting-needle biopsy (CNB) and fine-needle aspiration biopsy (FNAB) in chest lesions. A physician performed ultrasound and FNAB with a 22-G spinal needle in all patients, directly followed by a 14-G CNB in patients without contraindication. A total of 155 consecutive lesions arising from the lung (74%), pleura (12%), mediastinum (11%) or chest wall (3%) in patients with a final diagnosis of lung carcinoma (74%), other malignant tumours (12%), non-neoplastic disease (9%) or unknown (5%) were prospectively included. The overall diagnostic yield was 87%. Combined specimens were obtained in 123 lesions (79%). In these, yields of FNAB, CNB and both methods combined were 82, 76 and 89%, respectively. FNAB was significantly better than CNB in lung carcinoma (95 versus 81%) but CNB was superior in noncarcinomatous tumours and in benign lesions. On-site cytology was 90% sensitive and 100% specific for predicting a positive FNAB. One patient required drainage for pneumothorax (0.6%). Ultrasound-assisted fine-needle aspiration biopsy performed by chest physicians is an accurate and safe initial diagnostic procedure in patients with a high clinical probability of lung carcinoma. All other patients should undergo concurrent fine-needle aspiration biopsy and cutting-needle biopsy.


Current Opinion in Pulmonary Medicine | 2005

Transthoracic ultrasound for the pulmonologist

Andreas H. Diacon; Johan Theron; Chris T. Bolliger

Purpose of review Transthoracic ultrasound has received increased interest from chest physicians in recent years. Modern ultrasound devices are user friendly, inexpensive, lightweight, and portable, which makes them suited for outpatient settings as well as for bedside investigation of the severely ill. Ultrasound is set to become a practical and essential tool for the pulmonologist in the near future. Recent findings An ever-increasing number of articles are aimed at describing and refining how ultrasound can be utilised by chest physicians in daily practice. Only basic ultrasound skills are required to assess pleural effusions and perform ultrasound-guided thoracocentesis. Sonographic assistance with insertion of chest drains as well as identification or biopsy of thoracic masses are more complex, and advanced skills are required for the investigation of pneumothorax and thromboembolic disease. Summary The current literature documents the progress in the application of ultrasound for the practicing chest physician. In this article the authors describe the most recent developments and follow up with some simple but essential advice for the novice venturing into chest ultrasound.


Thorax | 2015

Targeted lung denervation for moderate to severe COPD: a pilot study

Dirk-Jan Slebos; Karin Klooster; Coenraad F.N. Koegelenberg; Johan Theron; Dorothy Styen; Arschang Valipour; Martin Mayse; Chris T. Bolliger

Background Parasympathetic pulmonary nerves release acetylcholine that induces smooth muscle constriction. Disruption of parasympathetic pulmonary nerves improves lung function and COPD symptoms. Aims To evaluate ‘targeted lung denervation’ (TLD), a novel bronchoscopic therapy based on ablation of parasympathetic pulmonary nerves surrounding the main bronchi, as a potential therapy for COPD. Methods This 1-year, prospective, multicentre study evaluated TLD in patients with COPD forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) (FEV1/FVC <0.70; FEV1 30%–60% predicted). Patients underwent staged TLD at 20 watts (W) or 15 W following baseline assessment off bronchodilators. Assessments were repeated on tiotropium before treatment and off bronchodilators at 30, 90, 180, 270 and 365 days after TLD. The primary endpoint was freedom from documented and sustained worsening of COPD directly attributable to TLD to 1 year. Secondary endpoints included technical feasibility, change in pulmonary function, exercise capacity, and quality of life. Results Twenty-two patients were included (n=12 at 20 W, n=10 at 15 W). The procedures were technically feasible 93% of the time. Primary safety endpoint was achieved in 95%. Asymptomatic bronchial wall effects were observed in 3 patients at 20 W. The clinical safety profiles were similar between the two energy doses. At 1 year, changes from baseline in the 20 W dose compared to the 15 W dose were: FEV1 (+11.6%±32.3 vs +0.02%±15.1, p=0.324), submaximal cycle endurance (+6.8 min±12.8 vs 2.6 min±8.7, p=0.277), and St Georges Respiratory Questionnaire (−11.1 points ±9.1 vs −0.9 points ±8.6, p=0.044). Conclusions Bronchoscopic TLD, based on the concept of ablating parasympathetic pulmonary nerves, was feasible, safe, and well tolerated. Further investigation of this novel therapy is warranted. Trial registration number NCT01483534.


Respiration | 2015

Time for the Global Rollout of Endoscopic Lung Volume Reduction

C F N Koegelenberg; Dirk-Jan Slebos; Pallav L. Shah; Johan Theron; Keertan Dheda; Brian W. Allwood; Felix J.F. Herth

Chronic obstructive pulmonary disease remains one of the most common causes of morbidity and mortality globally. The disease is generally managed with pharmacotherapy, as well as guidance about smoking cessation and pulmonary rehabilitation. Endoscopic lung volume reduction (ELVR) has been proposed for the treatment of advanced emphysema, with the aim of obtaining the same clinical and functional advantages of surgical lung volume reduction whilst potentially reducing risks and costs. There is a growing body of evidence that certain well-defined sub-groups of patients with advanced emphysema may benefit from ELVR, provided the selection criteria are met and a systematic approach is followed. ELVR devices, particularly unidirectional valves and coils, are currently being rolled out to many countries outside of the USA and Europe, although very few centres currently have the capacity to correctly evaluate and provide ELVR to prospective candidates. The high cost of these interventions underpins the need for careful patient selection to best identify those who may or may not benefit from ELVR-related procedures. The aim of this review is to provide the practicing pulmonologist with an overview of the practical aspects and current evidence for the use of the various techniques available, and to suggest an evidence-based approach for the appropriate use of these devices, particularly in emerging markets, where there should be a drive to develop and equip key specialised ELVR units.


Respiration | 2006

A patient with a persistent pleural effusion

Coenraad F.N. Koegelenberg; Johan Theron; Karen Brundyn; Chris T. Bolliger; A.D. Marais; Andreas H. Diacon

A pleural aspiration yielded a strikingly milky and odourless aspirate ( fi g. 4 A), which remained cloudy after being centrifuged ( fi g. 4 B) and left in a fridge overnight ( fi g. 4 C). The turbidity, however, was clearly altered by the addition of diethyl ether to the specimen ( fi g. 4 D). The pleural fl uid was classifi ed as an exudate with a total protein level of 42 g/l, lactate dehydrogenase of 74 U/l (normal ! 200 U/l) and adenosine deaminase of 7.3 U/l (normal ! 25 U/l). The cell count was 1,390/mm 3 with predominantly lymphocytes as well as a few foam cells. The fl uid had a pH of 7.4, contained no acid-fast bacilli, and cultures for Mycobacteria were negative. No malignant cells were found. What is the underlying cause for this extremely turbid effusion? A 73-year-old female was referred for the evaluation of a persistent pleural effusion. She initially presented to her general practitioner with recurrent bronchitis and was incidentally found to have a right-sided pleural effusion. The patient complained of a mild degree of dyspnoea on exertion and a decreased exercise tolerance, but denied pleuritic chest pain and previous trauma. She gave a seven-year history of recurrent respiratory tract infections, progressive lower limb swelling complicated by blisters with oozing and also complained of having brittle fi ngernails. Five years previously, she was extensively investigated for a pleural effusion, but numerous radiological investigations as well as a bronchoscopy and a thoracoscopy failed to yield a plausible diagnosis. The lady did not appear acutely ill and had clinical evidence of a moderate-size right-sided pleural effusion. She had gross non-pitting lymphoedema of both legs with areas of venous eczema ( fi g. 1 ). Her fi ngerand toenails were thickened, discoulored and dystrophic ( fi g. 2 ) and had an excessive curvature. There was a mild degree of onycholysis visible, and the lanulae and cuticles were absent. Our patient’s chest X-ray ( fi g. 3 ) and contrasted computed tomography showed a moderate, non-freefl owing, right-sided effusion with no evidence of other pulmonary, pleural or upper abdominal abnormality. Received: December 20, 2004 Accepted after revision: February 3, 2005 Published online: August 17, 2005


South African Medical Journal | 2015

Endoscopic lung volume reduction in severe emphysema

C F N Koegelenberg; Johan Theron; Johannes W. Bruwer; Brian W. Allwood; Morné J. Vorster; Florian von Groote-Bidlingmaier; Keertan Dheda

Therapeutic options in severe emphysema are limited. Endoscopic lung volume reduction (ELVR) refers to bronchoscopically inducing volume loss to improve pulmonary mechanics and compliance, thereby reducing the work of breathing. Globally, this technique is increasingly used as treatment for advanced emphysema with the aim of obtaining similar functional advantages to surgical lung volume reduction, while reducing risks and costs. There is a growing body of evidence that certain well-defined subgroups of patients with advanced emphysema benefit from ELVR, provided that a systematic approach is followed and selection criteria are met. In addition to endobronchial valves, ELVR using endobronchial coils is now available in South Africa. The high cost of these interventions underscores the need for careful patient selection to best identify those likely to benefit from such procedures.

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Dirk-Jan Slebos

University Medical Center Groningen

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Mercia Louw

Stellenbosch University

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Karin Klooster

University Medical Center Groningen

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