Cognitive Impairment due to Surgery or Postoperative Complications?
Ma, Daqing M.D., Ph.D.; Wan, Yanjie M.D.; Cibelli, Mario M.D.; Maze, Mervyn M.B., Ch.B., F.R.C.A.*
We thank the Editor for giving us the opportunity to respond to the questions about our work1
raised by Drs. Joana and Moeen Panni. Their suggestion that we should have included an additional group receiving a surgical incision plus bupivacaine infiltration is of interest. Less extensive surgery (i.e
., without incising the peritoneal cavity or dissecting around the splenic pedicle) could have resulted in less neuroinflammatory response and hence a shorter (or no) period of postoperative cognitive dysfunction; this contention is supported by clinical data showing that the incidence of postoperative cognitive dysfunction is lower after minor than after major surgical procedures.2
The possibility that removal of the spleen predisposes to infection is an important consideration because this organ can modulate the organism’s immune function, albeit much less in adults3
; interestingly, removal of an injured spleen does not enhance infectious complications in multiorgan-injury patients.4
Rats, in common with other rodents, are quite resistant to infective processes even after splenectomy complicated by fecal contamination.5
During our study, we also did not observe clinical evidence of postoperative infection. Last, we do not believe that surgery-induced immobility could have contributed to the splenectomized rats’ inability to learn because it was their choice of arm entry and not the speed or distance traveled that was assessed.
Daqing Ma, M.D., Ph.D.
Yanjie Wan, M.D.
Mario Cibelli, M.D.
Mervyn Maze, M.B., Ch.B., F.R.C.A.*
*Chelsea and Westminster Hospital, Imperial College London, United Kingdom. firstname.lastname@example.org
1. Wan Y, Xu J, Ma D, Zeng Y, Cibelli M, Maze M: Postoperative impairment of cognitive function in rats: A possible role for cytokine-mediated inflammation in the hippocampus. Anesthesiology 2007; 106:436–43
2. Newman S, Stygall J, Hirani S, Shaefi S, Maze M: Postoperative cognitive dysfunction after noncardiac surgery: A systematic review. Anesthesiology 2007; 106:572–90
3. Ackerman KD, Madden KS, Livnat S, Felten SY, Felten DL: Neonatal sympathetic denervation alters the development of in vitro
spleen cell proliferation and differentiation. Brain Behav Immun 1991; 5:235–61
4. Huizinga WK, Baker LW: The influence of splenectomy on infective morbidity after colonic and splenic injuries. Eur J Surg 1993; 159:579–84
5. Kestering Dde M, d’Acampora AJ, Farias DC, Brum SP, Ely JB: Rats resistance to fecal peritonitis when subjected to total splenectomy and auto-implant of the spleen in the retroperitoneum. Acta Cir Bras 2005; 20:473–7
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