Dr Arjun Rajagopalan

BIOPSYSagittal abdominal diameter is a better predictor than body mass

index for duration of laparoscopic left colectomy

We know … • Obesity increases the technical difficulty of laparoscopic

procedures and is associated with increased operative times.

• Body mass index (BMI) is the standard by which obesity is defined.

• However, fat distribution may be predominantly in subcutaneous tissue or intra-abdominal and the two types have different risk associations. BMI does not differentiate between the two types of fat distribution.

We don’t know … • CT scan based calculations are better indices of visceral

obesity. Could they be better predictors of technical difficulty and prolonged operation times?

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Background

Dr Arjun Rajagopalan

BIOPSY

1: PopulationAll patients undergoing elective, laparoscopic, left colorectal surgery - 121.

Dr Arjun Rajagopalan

POPULATION CHARACTERISTICSFactor Patients (121)

Type of resectionSigmoidectomy 61%

Left hemicolectomy 17%Low anterior resection 22%

Splenic flexure takedownDone 69%

Conversion to openDone 21%

Median BMI 25.4 kg/M2

Range 16.7 - 48.6

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Measurements

Dr Arjun Rajagopalan

• 2 observers who were unaware of surgical outcomes or operative times did the measurements

1

2

34

5 6Measured at L4-5

1 = SAD - saggital abdominal diameter 2 = S-int - saggital internal diameter 3 = T-int - transverse internal diameter 4 = T-ext - transverse external diameter 5 = Sc-fat - subcutaneous fat 6 = Perim - abdominal perimeter

3 & 4 taken at the level of the vena cava/ aorta

2: Indicator variable

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3: Outcomes

Operating time (mts)

125 250

225 min

248 min

SAD > 24.8 cmSAD < 24.8 cm

Dr Arjun Rajagopalan

• Although there was a trend for the other 5 variables there was no statistically significant difference in operating time.

• There was no correlation between BMI and operating time.

p = 0.04

Sampling Observational study

Centre University hospital, Switzerland

TImeframe January 2007 - December 2010

Analysis Retrospective

Sample sizing -

Exclusions Unavaliable CT, non-resectional procedures, single-incision surgery

Numbers 121 patients

ComparisonControls Randomisation Protocols Comparability

- - - -

MeasurementTraining Blinding Multi-observers Duplication

✅ ✅ ✅ ⛔️

CHECKLIST

Dr Arjun RajagopalanDr Arjun Rajagopalan

The author(s) conclude:

This study suggests that simple linear measures taken on a CT s c a n , s u c h a s s a g i t t a l abdominal diameter, sagittal internal diameter and abdominal perimeter, may predict longer operative time in laparoscopic left colonic resections more accurately than BMI.