A computed tomography study investigating the effects of botulinum toxin injections prior to complex abdominal wall reconstruction

OBJECTIVE

To explore how intramuscular injection of botulinum toxin A (BTA) affects the lateral abdominal wall (LAW) musculature, abdominal- and hernia dimensions, and muscle structure on computed tomography (CT) in patients scheduled for complex abdominal wall reconstruction (CAWR).

METHODS

Retrospective analysis of prospectively registered patients who received bilateral intramuscular BTA injections into all three muscles of the LAW. Only patients for which a CT was available before and 3-6 weeks after BTA treatment prior to surgery were analyzed.

RESULTS

Fifty-two patients were analyzed. Median hernia width in all patients decreased with 0.4 cm (IQR - 2.1;0.6) (p = 0.023). Median intra-abdominal transverse diameter increased with 0.9 cm (IQR - 0.2;3.3) (p = 0.001) and the intra-abdominal anterior-posterior diameter decreased with 0.5 cm (IQR - 1.3;0.5) (p = 0.017), making the abdomen more oval. Median LAW muscle length increased with 0.9 cm (IQR 0.0;2.4) per side (p < 0.001), muscle thickness decreased with 0.5 cm (IQR - 0.8;- 0.2) (- 25.0%) per side (p < 0.001), and muscle mass decreased with 3.9 cm2 (IQR - 6.4;-1.5) (- 15.8%) per side (p < 0.001). Median HU of the psoas muscles (density) increased with 4.8 HU (IQR 0.4;9.7) (10.3%) per side (p < 0.001). Effects of BTA were more pronounced in patients with a loss of domain (LoD) ≥ 20%.

CONCLUSIONS

The main effect of BTA injections is elongation and thinning of the LAW muscles, more than a decrease in hernia width. Concomitantly, the abdomen becomes more oval. An increase of psoas muscles density is seen, associated with offloading of the LAW muscles. Patients with large LoD have a proportionally higher effect of BTA.

A systematic review and meta-analysis of technical aspects and clinical outcomes of botulinum toxin prior to abdominal wall reconstruction

Purpose

To systematically review technical aspects and treatment regimens of botulinum toxin A (BTA) injections in the lateral abdominal wall musculature. We also investigated the effect of BTA on abdominal muscle- and hernia dimensions, and clinical outcome.

Methods

PubMed, EMBASE, CENTRAL, and CINAHL were searched for studies that investigate the injection of BTA in the lateral abdominal wall muscles. Study characteristics, BTA treatment regimens, surgical procedures, and clinical outcomes are presented descriptively. The effect of BTA on muscle- and hernia dimensions is analyzed using random-effects meta-analyses, and exclusively for studies that investigate ventral incisional hernia patients.

Results

We identified 23 studies, comprising 995 patients. Generally, either 500 units of Dysport^® or 200–300 units of Botox^® are injected at 3–5 locations bilaterally in all three muscles of the lateral abdominal wall, about 4 weeks prior to surgery. No major procedural complications are reported. Meta-analyses show that BTA provides significant elongation of the lateral abdominal wall of 3.2 cm per side (95% CI 2.0–4.3, I² = 0%, p < 0.001); 6.3 cm total elongation, and a significant but heterogeneous decrease in transverse hernia width (95% CI 0.2–6.8, I² = 94%, p = 0.04). Furthermore, meta-analysis shows that BTA pretreatment in ventral hernia patients significantly increases the fascial closure rate [RR 1.08 (95% CI 1.02–1.16, I² = 0%, p = 0.02)].

Conclusion

The injection technique and treatment regimens of botulinum toxin A as well as patient selection require standardization. Bilateral pretreatment in hernia patients significantly elongates the lateral abdominal wall muscles, making fascial closure during surgical hernia repair more likely.

Study registration

A review protocol for this meta-analysis was registered at PROSPERO (CRD42020198246).

Supplementary Information

The online version contains supplementary material available at 10.1007/s10029-021-02499-1.

The development and validation of risk-stratification models for short-term outcomes following contaminated complex abdominal wall reconstruction

BACKGROUND

Short-term outcomes for patients undergoing contaminated complex abdominal wall reconstruction (CCAWR), including risk stratification, have not been studied in sufficiently high numbers. This study aims to develop and validate risk-stratification models for Clavien-Dindo (CD) grade ≥ 3 complications in patients undergoing CCAWR.

METHODS

A consecutive cohort of patients who underwent CCAWR in two European national intestinal failure centers, from January 2004 to December 2015, was identified. Data were collected retrospectively for short-term outcomes and used to develop risk models using logistic regression. A further cohort, from January 2016 to December 2017, was used to validate the models.

RESULTS

The development cohort consisted of 272 procedures performed in 254 patients. The validation cohort consisted of 114 patients. The cohorts were comparable in baseline demographics (mean age 58.0 vs 58.1; sex 58.8% male vs 54.4%, respectively). A multi-variate model including the presence of intestinal failure (p < 0.01) and operative time (p < 0.01) demonstrated good discrimination and calibration on validation. Models for wound and intra-abdominal complications were also developed, including pre-operative immunosuppression (p = 0.05), intestinal failure (p = 0.02), increasing operative time (p = 0.04), increasing number of anastomoses (p = 0.01) and the number of previous abdominal operations (p = 0.02). While these models showed reasonable ability to discriminate patients on internal assessment, they were not found to be accurate on external validation.

CONCLUSION

Acceptable short-term outcomes after CCAWR are demonstrated. A robust model for the prediction of CD ≥ grade 3 complications has been developed and validated. This model is available online at www.smbari.co.uk/smjconv2.