Kim Wildgaard

Chronic post-thoracotomy pain: a critical review of pathogenic mechanisms and strategies for prevention

Chronic pain complaints after thoracic surgery represent a significant clinical problem in 25-60% of patients. Results from thoracic and other surgical procedures suggest multiple pathogenic mechanisms that include pre-, intra-, and postoperative factors. This review attempts to analyse the methodology and systematics of the studies on the post-thoracotomy pain syndrome (PTPS) after lung cancer surgery in adults, in order to clarify the relative role of possible pathogenic factors and to define future strategies for prevention. Literature published from 2000 to 2008 together with studies included in previous systematic reviews was searched recursively using PubMed and OVID by combining three categories of search terms. The available data have major inconsistencies in collection of pre-, intra- and postoperative data that may influence PTPS, thereby hindering precise conclusions as well as preventive and treatment strategies. However, intercostal nerve injury seems to be the most important pathogenic factor. Since there is a general agreement on the clinical relevance of PTPS, a proposal for design of future trials is presented.

Consequences of persistent pain after lung cancer surgery: a nationwide questionnaire study

Background: Post‐thoracotomy pain syndrome (PTPS) and its social consequences have been inconsistently investigated as most studies were either small sized, focused on a limited number of risk factors or included heterogeneous surgical procedures. The current objectives were to obtain detailed information on the consequences of PTPS after thoracotomy and video‐assisted thoracic surgery (VATS) from homogenous unselected nationwide data, and to suggest mechanisms for the development of PTPS.

Quantitative sensory testing of persistent pain after video-assisted thoracic surgery lobectomy

BACKGROUND Video-assisted thoracic surgery (VATS) lobectomy may potentially reduce the risk of post-thoracotomy pain syndrome (PTPS). However, it may still carry a risk of intraoperative nerve damage and thereby development of PTPS. Thus, our aim was to present a detailed long-term neurophysiological characterization of PTPS after VATS. METHODS Quantitative sensory testing, using thermal and mechanical stimuli, was performed in 13 PTPS patients and 35 pain-free patients recruited 33 months after VATS lobectomy. RESULTS When comparing the operated side with the control side in PTPS patients, increased thresholds of tactile and warmth detection were observed, while in pain-free patients, increased thresholds of warmth detection, cool detection, and heat pain were demonstrated. At the anterior porthole, pain-free patients displayed increased threshold to thermal detection when compared with the control side. Only side-to-side difference for tactile detection threshold was increased in PTPS patients compared with pain-free patients. Assessment of central sensitization showed no significant differences within or between PTPS and pain-free patients nor did group comparison of area of hypo- and hyperaesthesia to cool. Anxiety and depression scores (HADS) were higher in PTPS patients, but the area of hyper- and hypoaesthesia did not differ significantly between HADS groups. CONCLUSIONS Increased sensory thresholds suggest nerve injury to be present on the operated side in both PTPS and pain-free patients. However, no significant quantitative differences between PTPS and pain-free patients could be found, implicating the presence of factors other than intercostal nerve injury as important for development of PTPS after VATS lobectomy.

Neurophysiological characterization of persistent postthoracotomy pain.

ObjectivesThe postthoracotomy pain syndrome (PTPS) has a prevalence of 30% to 40%. Although intraoperative nerve damage during thoracotomy has been demonstrated, it has not been clearly linked to PTPS and detailed quantitative sensory characterization data have so far not been presented, comparing PTPS and pain-free patients. MethodsNeurophysiological characterization was performed in 17 patients with PTPS and 24 pain-free postthoracotomy patients using a detailed quantitative sensory testing protocol and psychometric questionnaires. ResultsPain and pain-free patients had increased thresholds to tactile detection (P=0.001 and P=0.01) and cool detection (P<0.001 and P<0.01) on the operated side versus the contralateral side. Pain patients also had increased thresholds for warmth detection (P<0.001) and heat pain (P<0.01) on the operated side. The PTPS patients demonstrated increased side-to-side differences for warmth detection (P<0.01), heat pain (P<0.05), and cool detection (P<0.05) thresholds compared with pain-free patients. Pain patients also more frequently experienced cool hyperesthesia (8 of 17 vs. 1 of 24, P<0.01), but no differences were found for pressure pain, temporal summation, or sensory mapping to cool (200 cm2 vs. 76 cm2, P=0.18). Hospital Anxiety and Depression Scale scores were higher for PTPS than for pain-free patients (P<0.01). DiscussionNeurophysiological assessments indicate nerve injury to be common in pain and pain-free patients after thoracotomy. The combination of increased thresholds together with hyperesthesia, suggests consequences of nerve injury to be more pronounced in PTPS patients.

Chronic Pain After Lung Transplantation A Nationwide Study

ObjectivesLittle is known about persistent postsurgical pain after lung transplantation with the associated intensive and continuous immunosuppressive treatment. Therefore, we investigated the nationwide incidence of chronic pain after lung transplantations. MethodsDetailed questionnaires were sent to all 110 Danish surviving recipients of lung transplantation from September 2002 to September 2007. ResultsSeventy-nine patients fulfilled the inclusion criteria with a mean follow-up time of 39 months. Excluded patients were 1 death during survey, 14 with previous thoracic surgery, and 16 patients who did not respond to an initial mailed questionnaire or a reminder. Fourteen patients (18%) reported persistent pain, whereas only 8 patients (10%) reported pain score >3 (numeric rating scale 0 to 10) and 4 patients (5%) >5 (numeric rating scale 0 to 10). Seventy-one percent of the patients with postsurgical pain also had pain from another part of the body. In patients with persistent postsurgical pain, this was a limiting factor for daily social activities in 29% to 92% dependent on the activity and 54% in pain felt quality of life was compromised due to the pain. Seventy-three percent of persistent postsurgical pain patients (lateral thoracotomy) experienced sensory disturbances compared with 46% of nonpain patients. DiscussionModerate-to-severe persistent postsurgical pain occurred in 5% to 10% of patients after lung transplantation, which is lower than reported after nontransplant thoracotomy. The specific role of the peritransplant immunosuppression on persistent post-thoracotomy pain should be explored further.

Regional analgesia for video-assisted thoracic surgery: a systematic review.

Video-assisted thoracic surgery (VATS) is emerging as the standard surgical procedure for both minor and major oncological lung surgery. Thoracic epidural analgesia (TEA) and paravertebral block (PVB) are established analgesic golden standards for open surgery such as thoracotomy; however, there is no gold standard for regional analgesia for VATS. This systematic review aimed to assess different regional techniques with regard to effect on acute postoperative pain following VATS, with emphasis on VATS lobectomy. The systematic review of PubMed, The Cochrane Library and Embase databases yielded 1542 unique abstracts; 17 articles were included for qualitative assessment, of which three were studies on VATS lobectomy. The analgesic techniques included TEA, multilevel and single PVB, paravertebral catheter, intercostal catheter, interpleural infusion and long thoracic nerve block. Overall, the studies were heterogeneous with small numbers of participants. In comparative studies, TEA and especially PVB showed some effect on pain scores, but were often compared with an inferior analgesic treatment. Other techniques showed no unequivocal results. No clear gold standard for regional analgesia for VATS could be demonstrated, but a guide of factors to include in future studies on regional analgesia for VATS is presented.

Sensory testing in patients with postthoracotomy pain syndrome: Part 1: mirror-image sensory dysfunction.

Objectives:Mirror-image sensory dysfunction (MISD) has not been systematically characterized in persistent postoperative pain. Methods:The presence of MISD was evaluated with standardized stimuli, in preoperative patients scheduled for a thoracotomy (n=14) and in patients with postthoracotomy pain syndrome [PTPS (n=14)]. The primary outcome was investigation of the areas of sensory dysfunction, evaluated twice by dynamic sensory mapping with metal rollers and a brush. Results:In PTPS patients, sensory dysfunction was present on the surgical side, and in 12 of 14 patients MISD was demonstrated. The total areas of sensory dysfunction [median (interquartile range)] were: day 1, 500 (289 to 636) cm2 and 60 (0 to 379) cm2 on the surgical and nonsurgical side (P<0.005), respectively; and day 2, 355 (266 to 697) cm2 and 81 (0 to 202) cm2 on the surgical and nonsurgical side (P<0.0002), respectively. Magnitudes of areas on the surgical side, respective of the nonsurgical side, did not significantly differ between the 2 days of investigation (P>0.5). The agreement between test-retest assessments was fair to excellent on the surgical side but poor on the nonsurgical side. None of the PTPS patients experienced mirror pain. Discussion:MISD is a common finding in PTPS patients and deserves further study involving mechanism and clinical implications.

Persistent postsurgical pain after video‐assisted thoracic surgery – an observational study

The risk of persistent postsurgical pain (PPP) and subsequent pain‐related functional impairment may potentially be reduced by video‐assisted thoracic surgery (VATS) compared to thoracotomy. The aim of the study was therefore to assess in detail the incidence and consequences on activities of daily living of PPP after VATS.

Pain-related impairment of daily activities after thoracic surgery: a questionnaire validation.

Objective:Persistent postoperative pain is an acknowledged entity that reduces daily activities. Evaluation of the post-thoracotomy pain syndrome (PTPS) is often measured using traditional pain scales without in-depth questions on pain impairment. Thus, the purpose was to create a procedure-specific questionnaire for assessment of functional impairment due to PTPS. Methods:Activities were obtained from the literature supplemented by interviews with patients and surgeons. The questionnaire was validated using the Rasch model in order to describe an underlying pain impairment scale. Results:Four of 17 questions were redundant. The remaining 13 questions from low to intensive activity described functional impairment following persistent pain from thoracotomy and video-assisted thoracic surgery (VATS). No evidence for differential item functioning for gender, age or differences between open or VATS, were found. A generalized log-linear Rasch model including local dependence was constructed. Though local dependence influenced reliability, the test-retest reliability estimated under the log-linear Rasch model was high (0.88–0.96). Correlation with items from the Disability of the Arm, Shoulder and Hand (quick) questionnaire supported validity (&ggr;=0.46, P<0.0001), and procedure specificity. The analysis also procured evidence that the pain impairment questionnaire measured 2 qualitatively different pain dimensions although highly correlated (&ggr;=0.76). Conclusions:This study presents method, results and validation of a new unidimensional scale measuring procedure specific functional impairment due to PTPS following open surgery and VATS. Procedure specific tools such as this could provide important outcomes measures for future trials on persistent postsurgical pain states allowing better assessment of interventions (250).

Medical care and organisation at the 2012 Roskilde Music Festival: a prospective observational study

Music festivals, with a mix of music, alcohol and camping at the festival site combined with low hygiene, have become an integral part of society and attracts large numbers of guests. Our study was performed in order to increase the very limited knowledge on health‐care issues and organisation of major music festivals.