The effect of preoperative botulinum toxin a injection on traction force during hernia repair: a prospective, single-blind study, intra-patient comparison using contralateral side as a control

Abstract

Purpose: Ventral hernias are a common complication of laparotomy, posing challenges particularly when primary fascial closure is unattainable. Although chemical component separation using preoperative botulinum toxin A (BTX) injections has emerged as a promising adjunct, objective evidence of its efficacy remains limited. This study aimed to objectively assess the effect of preoperative BTX on traction force during ventral hernia repair.

Methods: A prospective, single-blind study was conducted on patients with midline incisional hernias following liver transplantation. BTX was administered unilaterally, and the traction force required to medially advance the anterior rectus sheath was measured intraoperatively. Pre- and post-injection CT scans were analyzed for changes in hernia size and LAW muscle measurements. Statistical analyses were performed to evaluate traction force differences between BTX-injected and uninjected sides.

Results: Ten patients underwent hernia repair with primary fascial closure achieved in all cases. Comparison of pre- and post-injection CT scans showed no significant changes in hernia size. LAW muscle length increased by 1.8 cm, while thickness decreased by 0.2 cm. Intraoperative traction force measurements revealed a significant reduction on the BTX-injected side compared to the uninjected side (p < 0.0001). The traction force ratio on the BTX-injected to the uninjected side averaged 57%, indicating the efficacy of BTX in reducing tension.

Conclusion: Preoperative BTX significantly reduces traction force during ventral hernia repair, highlighting its potential as an adjunctive therapy in complex cases. While challenges remain in patient selection and outcome assessment, BTX offers a promising avenue for enhancing abdominal wall reconstruction outcomes and reducing surgical complications.

Keywords: Abdominal wall; Botulinum toxins, type A; Hernia, ventral; Herniorrpaphy.

Fig. 1

Traction force measurement The measurement was conducted using a digital scale, taken at 0.5 cm intervals from 1 cm to a maximum of 5 cm, or until the fascia was on the verge of tearing, even if beyond the midline. The example illustration shows a traction force of 770 gf measured at 1.5 cm

Fig. 2

Mean traction force according to the distance of medial advancement The estimated mean traction force was 641.08 gf for BTX-injected group and 942.57 gf for BTX-uninjected group, indicating a significant difference (p < 0.0001). When the interaction effect between the two groups (BTX-injected and BTX-uninjected) regarding traction force (absolute value) across different distances were analyzed, the effect of BTX on traction force was significantly influenced by pulling distance (p for interaction = 0.0007)

Fig. 3

Traction force ratio comparing the injected side to the uninjected side across distances of medial advancement BTX reduced the traction force required for the medial advancement of the anterior rectus sheath to 57% on average. There was a trend toward a slight increase in the ratio on the injected to the uninjected side from 2 cm onward, without statistical significance (p = 0.783)