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Arch Dis Child. 2007 July; 92(7): 655.
PMCID: PMC2083771

Blunted inflammatory and faster clinical recovery following laser treatment compared to cryotherapy

We read with great interest the letter of Anand et al in this journal on the use of different modes of analgesia and anaesthesia during retinal surgery for retinopathy of prematurity (ROP).1 We fully agree that the administration of medication for sedation, analgesia and paralysis on the neonatal ward avoids delay in treatment and eliminates the unnecessary transfer of neonates before and following surgery.2 We would like to mention an additional point not yet considered in the current analysis, that is, the potential impact of the type of surgery on perioperative management and outcome. Cryotherapy and laser photocoagulation are both effective in preventing visual impairment for threshold ROP. In contrast, there are almost no reports on non‐ophthalmological outcome. We therefore retrospectively evaluated the effect of the surgical technique on postoperative clinical management and inflammatory response, based on retrospective analysis of postoperative management of infants who received cryotherapy (2000–2001) or laser photocoagulation (2001–2005) but otherwise underwent the same postoperative standardised approach. Duration of postoperative ventilation and of administration of analgesics and time until full enteral feeding was recommenced were recorded. C‐reactive protein (CRP) values in the first week after surgery were collected. Retinal surgery was performed in 35 infants. Sixteen infants were treated with cryotherapy and 19 received laser photocoagulation. There were no significant differences in birth weight, gestational age at birth, weight or postnatal age at surgery between both groups. In contrast, a significant decrease in duration of postoperative ventilation (hours, p<0.02) and in duration of intravenous analgesics (hours, p<0.03) was observed. Finally, the time until full enteral feeding was recommenced (hours, p<0.05) was significantly shorter in infants who received laser photocoagulation.3 A similar study on the absence of CRP increase following laser treatment in this journal stimulated us to evaluate the impact of type of surgery.4 In the same cohort, data on 56 CRP values were available, of which 31 were in infants after cryoablation and 25 in infants after laser photocoagulation. The median CRP level after cryoablation was significantly higher compared to the median CRP level after laser photocoagulation (p = 0.02, all Mann Whitney U tests).5

We therefore conclude that the use of laser photocoagulation for threshold retinopathy was associated with a faster postoperative recovery and a blunted inflammatory response compared to cryo‐treated infants. The differences in surgical technique might therefore further contribute to the differences in anaesthetic management and postoperative outcome.


Competing interests: None declared.


1. Anand D, Etuwewe B, Clark D. et al Anaesthesia for treatment of retinopathy of prematurity. Arch Dis Child Fetal Neonatal Ed 2007. 92154–155.155
2. Allegaert K, Van de Velde M, Debeer A. et al Cryotherapy versus laser photocoagulation for threshold retinopathy of prematurity: impact on short term postoperative management. Bull Belge Ophthalmol 2006. 3007–10.10
3. Allegaert K, Tibboel D. Shouldn't we reconsider procedural techniques to prevent neonatal pain? Eur J Pain. 2007 Mar 16; [Epub ahead of print]. Doi: 10.1016/j.ejpain.2007.01.007
4. Daniels J G, Adams G G. Effect of laser photocoagulation for retinopathy of prematurity on C reactive protein. Arch Dis Child Fetal Neonatal Ed 2004. 89F470
5. Allegaert K, Devlieger H, Casteels I. Reduced inflammatory response after laser photocoagulation compared with cryoablation for threshold retinopathy of prematurity. J Pediatr Ophthalmol Strabismus 2005. 42264–266.266 [PubMed]

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