title: The spinal needle test effectively measures abdominal wall thickness before cannula placement at laparoscopy.
abstract: OBJECTIVE
  To demonstrate the usefulness of the spinal needle test at laparoscopy to correlate abdominal wall thickness at initial entry sites with body mass index (BMI).
  
  
  METHODS
  Prospective cohort study (Canadian Task Force classification).
  
  
  METHODS
  University-affiliated hospital.
  
  
  METHODS
  One hundred thirty-eight women.
  
  
  METHODS
  Diagnostic laparoscopy.
  
  
  RESULTS
  After CO(2) insufflation, the spinal needle test was performed by inserting a spinal needle attached to a partially filled syringe and advancing it perpendicular to the skin until the gas pocket was reached. To improve precision, the distance was measured 3 times at two sites, the umbilicus and Palmer's point (left upper quadrant). Patients' mean BMI was 25.8 kg/m(2) (range 17.2-60.0 kg/m(2)), with 24 (17%) considered clinically obese (BMI > or =30 kg/m(2)). A significant correlation was noted between BMI and abdominal wall thickness at the umbilicus (R = 0.69) and left upper quadrant (R = 0.81). Excellent correlation was also noted between body weight and thickness at the two points (R = 0.72 and R = 0.78, respectively). The mean thickness at the umbilicus differed significantly between obese (3.0 +/- 1.2 cm) and nonobese women (1.7 +/- 0.7 cm, p <0.001); as did mean thickness at the left upper quadrant (4.4 +/- 1.0 vs 2.0 +/- 0.7 cm, p <0.001).
  
  
  CONCLUSIONS
  Thickness of the abdominal wall at umbilical and left upper quadrant entry sites correlates well with weight and BMI. Even among obese women, the distance to the pocket of gas after insufflation at either entry site is remarkably small.
authors.affiliation: Department of Obstetrics and Gynecology, Northwestern University Medical School, 333 East Superior Street, Suite 1564, Chicago, IL 60611.
authors.forename: Magdy P
authors.initials: MP
authors.lastname: Milad
authors.forename: Mary Faith
authors.initials: MF
authors.lastname: Terkildsen
mesh_terms: D034861:Abdominal Wall / Q000033:anatomy & histology*; D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D013509:Gynecologic Surgical Procedures / Q000379:methods; D006801:Humans; D020706:Laparoscopes; D010535:Laparoscopy / Q000379:methods; D008875:Middle Aged; D009339:Needles; D009765:Obesity / Q000175:diagnosis*; D011028:Pneumoperitoneum, Artificial / Q000295:instrumentation* / Q000379:methods; D011300:Preoperative Care; D011446:Prospective Studies; D012680:Sensitivity and Specificity