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Efficacy of the intertransverse process block: single or multiple injection? A randomized, non-inferiority, blinded, cross-over trial in healthy volunteers
  1. Martin Vedel Nielsen1,
  2. Katrine Tanggaard1,
  3. Sophie Bojesen2,
  4. Amanda de la Fuente Birkebæk1,
  5. Anne Sofie Therkelsen1,
  6. Herman Sørensen1,
  7. Cecilie Klementsen1,
  8. Christian Hansen1,
  9. Mojgan Vazin1,
  10. Troels Dirch Poulsen1 and
  11. Jens Børglum1,3
  1. 1Department of Anesthesiology and Intensive Care Medicine, Zealand University Hospital, Roskilde, Denmark
  2. 2Department of Plastic and Breast Surgery, Zealand University Hospital, Roskilde, Denmark
  3. 3Department of Clinical Medicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
  1. Correspondence to Dr Martin Vedel Nielsen, Department of Anesthesiology and Intensive Care Medicine, Zealand University Hospital Roskilde, Roskilde, Denmark; martinvedel{at}


Introduction The intertransverse process block is increasingly used to ameliorate postoperative pain following a plethora of surgical procedures involving the thoracic wall. Nevertheless, the optimal approach and cutaneous extent of the sensory block are currently unknown. We aimed to further describe the intertransverse process block, single injection versus multiple injection, and we hypothesized that the single-injection intertransverse process block is a non-inferior technique.

Methods Twelve healthy male volunteers were cross-over randomized to receive either single-injection intertransverse process block with 21 mL ropivacaine 7.5 mg/mL, including two sham injections, at the thoracic level T4/T5 or multiple-injection intertransverse process block with three injections of 7 mL ropivacaine 7.5 mg/mL at the thoracic levels T2/T3, T4/T5 and T6/T7 at the first visit. At the second visit, the other technique was applied on the contralateral hemithorax. A non-inferiority margin of 1.5 anesthetized thoracic dermatomes was chosen.

Results The mean difference (95% CI) in the number of anesthetized thoracic dermatomes was 0.82 (−0.41 to 2.05) pnon-inf<0.01 indicating non-inferiority favoring the single-injection technique.

Both techniques anesthetized the ipsilateral thoracic wall and demonstrated contralateral cutaneous involvement to a variable extent. The multiple-injection intertransverse process block anesthetized a significantly larger cutaneous area on the posterior hemithorax and decreased mean arterial pressure at 30 and 60 min postblock application. Thoracic thermography showed no intermodality temperature differences yet compared with baseline temperatures both techniques showed significant differences.

Conclusions Single-injection intertransverse process block is non-inferior to multiple injection in terms of anesthetized thoracic dermatomes. Both techniques generally anesthetize the hemithoracic wall to a variable extent.

EU clinical trials register 2022-501312-34-01.

  • Anesthesia, Local
  • Methods
  • Nerve Block
  • Pain, Postoperative

Data availability statement

Data are available on reasonable request.

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Data availability statement

Data are available on reasonable request.

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  • Contributors MVN: planning, designing, conducting, acquisition of data, analyzing data, reporting, interpreting data, and writing the manuscript. KT, SB, AdlFB, AST, HS, CK, CH, MV and TDP: conducting, interpreting data, and writing the manuscript. JB: planning, designing, conducting, acquisition of data, analyzing data, reporting, interpreting data, and writing the manuscript. MVN stands as guarantor for the overall content.

  • Funding MVN has received donations from Region Zealand Health Science Foundation and Lægefonden, A. P. Møller Mærsk.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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