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Investigating the effect of intra-operative infiltration with local anaesthesia on the development of chronic postoperative pain after inguinal hernia repair. A randomized placebo controlled triple blinded and group sequential study design [NCT00484731].

Honigmann P, Fischer H, Kurmann A, Audigé L, Schüpfer G, Metzger J - BMC Surg (2007)

Bottom Line: Using a group sequential study design the minimum number of patients are enrolled to reach a valid conclusion before the end of the study.To limit subjectivity, both a VAS and the Pain Matcher device are used for the evaluation of pain.We hope to significantly reduce the occurrence of this complication with our investigated intervention.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Kantonsspital Luzern, Luzern, Switzerland. philipp.honigmann@ksl.ch

ABSTRACT

Background: Inguinal hernia repair is one of the most frequently performed procedures in Switzerland (15'000/year). The most common complication postoperatively is development of chronic pain in up to 30% of all patients irrespective of the operative technique.

Methods/design: 264 patients scheduled for an inguinal hernia repair using one of three procedures (Lichtenstein, Barwell and TEP = total extraperitoneal hernioplasty) are being randomly allocated intra-operatively into two groups. Group I patients receive a local injection of 20 ml Carbostesin 0.25% at the end of the operation according to a standardised procedure. Group II patients get a 20 ml placebo (0.9% Saline) injection. We use pre-filled identically looking syringes for blinded injection, i.e. the patient, the surgeon and the examinator who performs the postoperative clinical follow-ups remain unaware of group allocation. The primary outcome of the study is the occurrence of developing chronic pain (defined as persistent pain at 3 months FU) measured by VAS and Pain Matcher device (Cefar Medical AB, Lund, Sweden). The study started on July 2006. In addition to a sample size re-evaluation three interim analyses are planned after 120, 180 and 240 patients had finished their 3-months follow-up to allow for early study termination.

Discussion: Using a group sequential study design the minimum number of patients are enrolled to reach a valid conclusion before the end of the study. To limit subjectivity, both a VAS and the Pain Matcher device are used for the evaluation of pain. This allows us also to compare these two methods and further assess the use of Pain Matcher in clinical routine. The occurrence of chronic pain after inguinal hernia repair has been in focus of several clinical studies but the reduction of it has been rarely investigated. We hope to significantly reduce the occurrence of this complication with our investigated intervention.

Trial registration: Our trial has been registered at ClinicalTrials.gov. The trial registration number is: [NCT00484731].

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Pain Matcher®
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Figure 4: Pain Matcher®

Mentions: The Pain Matcher® (Cefar Medical AB, Lund, Sweden; Figure 4) is a perceptual matching device unit that gives constant current stimulation which is controlled by a microprocessor that provides rectangular pulses with a frequency of 10 Hz and an amplitude of 10 mA. It is programmed to give a constant current stimulation despite variable skin resistance (e.g., influenced by sweating and anxiety of the subject) up to 13 kΩ. The intensifying of stimulation is achieved by successively increasing the pulse width from 0 to a possible maximum of 450 μs in increments of 7.5 μs, up to a total of 60 steps. The electrical charge per second is extremely low and varies through the different steps from 1.5 to 45 μC. The reached value (0–100) is directly related to the pulse width and is displayed on a liquid crystal display screen. The contact surface area, and hence the resulting current density, is ensured by a certain minimum finger pressure against the electrode; this is achieved by instructing the patient to hold the electrode box between the thumb and the index finger in a horizontal position requiring a certain minimum, predetermined pressure. A further increase in electrode pressure does not improve the functionality of the Pain Matcher®.


Investigating the effect of intra-operative infiltration with local anaesthesia on the development of chronic postoperative pain after inguinal hernia repair. A randomized placebo controlled triple blinded and group sequential study design [NCT00484731].

Honigmann P, Fischer H, Kurmann A, Audigé L, Schüpfer G, Metzger J - BMC Surg (2007)

Pain Matcher®
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2198905&req=5

Figure 4: Pain Matcher®
Mentions: The Pain Matcher® (Cefar Medical AB, Lund, Sweden; Figure 4) is a perceptual matching device unit that gives constant current stimulation which is controlled by a microprocessor that provides rectangular pulses with a frequency of 10 Hz and an amplitude of 10 mA. It is programmed to give a constant current stimulation despite variable skin resistance (e.g., influenced by sweating and anxiety of the subject) up to 13 kΩ. The intensifying of stimulation is achieved by successively increasing the pulse width from 0 to a possible maximum of 450 μs in increments of 7.5 μs, up to a total of 60 steps. The electrical charge per second is extremely low and varies through the different steps from 1.5 to 45 μC. The reached value (0–100) is directly related to the pulse width and is displayed on a liquid crystal display screen. The contact surface area, and hence the resulting current density, is ensured by a certain minimum finger pressure against the electrode; this is achieved by instructing the patient to hold the electrode box between the thumb and the index finger in a horizontal position requiring a certain minimum, predetermined pressure. A further increase in electrode pressure does not improve the functionality of the Pain Matcher®.

Bottom Line: Using a group sequential study design the minimum number of patients are enrolled to reach a valid conclusion before the end of the study.To limit subjectivity, both a VAS and the Pain Matcher device are used for the evaluation of pain.We hope to significantly reduce the occurrence of this complication with our investigated intervention.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Kantonsspital Luzern, Luzern, Switzerland. philipp.honigmann@ksl.ch

ABSTRACT

Background: Inguinal hernia repair is one of the most frequently performed procedures in Switzerland (15'000/year). The most common complication postoperatively is development of chronic pain in up to 30% of all patients irrespective of the operative technique.

Methods/design: 264 patients scheduled for an inguinal hernia repair using one of three procedures (Lichtenstein, Barwell and TEP = total extraperitoneal hernioplasty) are being randomly allocated intra-operatively into two groups. Group I patients receive a local injection of 20 ml Carbostesin 0.25% at the end of the operation according to a standardised procedure. Group II patients get a 20 ml placebo (0.9% Saline) injection. We use pre-filled identically looking syringes for blinded injection, i.e. the patient, the surgeon and the examinator who performs the postoperative clinical follow-ups remain unaware of group allocation. The primary outcome of the study is the occurrence of developing chronic pain (defined as persistent pain at 3 months FU) measured by VAS and Pain Matcher device (Cefar Medical AB, Lund, Sweden). The study started on July 2006. In addition to a sample size re-evaluation three interim analyses are planned after 120, 180 and 240 patients had finished their 3-months follow-up to allow for early study termination.

Discussion: Using a group sequential study design the minimum number of patients are enrolled to reach a valid conclusion before the end of the study. To limit subjectivity, both a VAS and the Pain Matcher device are used for the evaluation of pain. This allows us also to compare these two methods and further assess the use of Pain Matcher in clinical routine. The occurrence of chronic pain after inguinal hernia repair has been in focus of several clinical studies but the reduction of it has been rarely investigated. We hope to significantly reduce the occurrence of this complication with our investigated intervention.

Trial registration: Our trial has been registered at ClinicalTrials.gov. The trial registration number is: [NCT00484731].

Show MeSH
Related in: MedlinePlus