Introduction Laparoscopic colorectal surgery is the preferred approach for colorectal resections. It often requires extreme positioning for many hours, including extreme head-down tilts. The incidence of perioperative visual loss after colorectal surgery is quoted as 1.24 per 10,000 in USA¹and is thought to be due to raised IOP leading to reduced optic nerve head perfusion.^1,2

Aim This study assesses the effect of head-down tilt on IOP during laparoscopic colorectal surgery.

Method Patients undergoing laparoscopic colorectal resections are included in this study. It is hypothesised that right-sided resections generally spend less time in the head-down position compared to left-sided and sub-total resections. Therefore, Group 1 included those undergoing right-sided resections and Group 2 included left-sided and sub-total resections. Baseline eye examination and IOP measurements using a Tonopen® XL applanation tonometer were carried out every hour during surgery and each time when the operating table was tilted.

Results There were 30 patients (16 males, 14 females) in the study with an average age of 63 years (Range 25–78); with Group 1’s mean age 63.5 years (SD 14.35) and Group 2 had a mean age of 62.3 years (SD 17.68), (p > 0.05). Group 1 had 14 patients and Group 2 had 16 patients. The mean length of surgery (LOS) for Group 1 was 2 hrs. 27 mins (SD 0.73) and for Group 2 mean LOS was 4 hrs. 7 mins (SD 1.63) with P = 0.001. The baseline IOP was similar in both groups with the mean baseline IOP in Group 1 being 16.69mmHg, and in Groups 2 it was 16.87 mmHg (p > 0.05). The median IOP rise from baseline during surgery was 10.5 mmHg (IQR = 4.5) in Group 1 and 18 mmHg (IQR = 4.4) in Group 2 (p < 0.05). The median maximum degree of head down tilt during surgery in Group 1 was 9.3^°(IQR = 7.2) and Group 2 was 18.3° (IQR = 8.4), (p < 0.05).

Conclusion A rise in IOP occurs during laparoscopic colorectal surgery and it appears to be more pronounced in those with a greater degree of head down tilt for a prolonged time. This may have important implications for those patients undergoing prolonged surgery and for those with a history of glaucoma.

Disclosure of interest None Declared.

References

1. Molloy BL. Implications for postoperative visual loss: steep Trendelenburg position and effects on intraocular pressure. AANA J. 2011;79(2):115–121

2. Awad H, Santilli S, Ohr M, Roth A, Yan W, Fernandez S, Roth S, Patel V. The effects of steep trendelenburg positioning on intraocular pressure during robotic radical prostatectomy. Anesth Analg. 2009;109(2):473–8