Combined interrupted and continuous versus single continuous adjustable suturing in penetrating keratoplasty: A prospective, randomized study of induced astigmatism during the first postoperative year1☆
Received 16 December 1997; accepted 19 May 1998.
Abstract
Objective
To compare postoperative astigmatism induced by two different suturing techniques in penetrating keratoplasty (PKP).
Design
A monocenter, prospective, randomized clinical trial with a longitudinal 1-year follow-up.
Participants
A total of 95 eyes undergoing PKP were randomized into 2 groups. Of these, 51 eyes were allocated to the combined interrupted and continuous suturing group (ICS) and 44 eyes to the single continuous adjustable suturing (SCAS) group.
Intervention
In the ICS group, suturing was with a combination of 12 interrupted 10-0 nylon and 1 continuous 11-0 nylon sutures. Eyes in the SCAS group had been sutured with a single running 24-bite 10-0 nylon. Selective suture removal started no earlier than 10 weeks after surgery; suture adjustment could start as soon as possible after surgery.
Main outcome measures
Astigmatism was measured by topography, keratometry, and refraction at 3-, 6-, 9-, and 12-month postoperative intervals.
Results
The difference in mean time of suture manipulation between groups was significant (P = 0.0001), with the SCAS starting earlier. A significant decrease in astigmatism occurred by either interrupted suture removal (6.69 ± 3.11 diopter [D] before to 4.76 ± 2.99 D after, P = 0.0002) or suture adjustment (7.18 ± 3.12 D before to 4.46 ± 3.24 D after, P = 0.0001). However, the net astigmatic reduction in the SCAS group was not significantly greater (P = 0.250) than in the ICS group. Vector change was 7.40 ± 4.17 D and 6.28 ± 4.14 D for SCAS and ICS, respectively (P = 0.13). At no interval (3, 6, 9, or 12 months) was there significant difference in astigmatism between the two groups. Refractive astigmatism (cyl, D) at 1 year was 2.66 ± 1.70 for the ICS and 3.12 ± 2.62 for the SCAS, but there was no significant treatment effect (P = 0.945). Furthermore, 66% of the ICS eyes and 58% of the SCAS eyes (P = 0.295) were within the astigmatic target of the study (<3.5 D).
Conclusions
Postkeratoplasty astigmatism can be decreased similarly with either adjustment of a single running suture or selective removal of interrupted sutures. No advantage of the SCAS over ICS in terms of fewer manipulations or less astigmatism was seen as suggested previously.
Manuscript no. 97855.
aDepartment of Ophthalmology, Bristol Eye Hospital, Bristol, England UK
Address correspondence and reprint requests to Constantinos H. Karabatsas, MD, FRCS, P.O. Box 16757, Athens 11502, Greece
☆ Supported in part by a grant (to CHK) from the Greek State Foundation (IKY) (grant no: 721472787).
1 None of the authors have any proprietary interest in any of the instruments used in the study.
ABSTRACT