Suture-Related Complications after Penetrating Keratoplasty at King Hussein Medical Center

Spontaneous loosening or breakage of sutures occurred in 12 patients, two of them required re-suturing due to early wound dehiscence or manifest leakage from the wound. The average time interval between PKP and the occurrence of breakage was seven months (SD±5.16, range 1-15 months) (see Table I).

Suture related abscesses were also seen in four patients, they came complaining of pain and injected eyes. Two of them had ulcerative epithelial defects with stromal infiltrates adjacent to loose irritating sutures while the other two presented with infiltrates and hypopyon one week following selective suture removal. All patients were cultured, the results revealed Streptococcus pneumoniae in two patients, Staphylococcus aureus in one patient, and no growth in the fourth patient; this however was considered infectious because of the presence of hypopyon and good response to fortified topical antibiotic treatment. The average time between surgery and occurrence of abscesses was 14 months (SD±10.73, range 7-30 months).

Three of these patients were admitted to hospital; all were treated with daily sub-conjunctival injection of antibiotics for four days and vigorous topical fortified eye drops and responded well.

One of the patients developed endophthalmitis and received intravitreal antibiotic injection and also responded well but experienced a decrease of two lines of visual acuity.

Sterile infiltrates were found in 10 patients (13.3%), mostly as small sub-epithelial infiltrates adjacent to sutures more often on the recipient side.  All were symptom free and only were detected at routine follow up visits.  Close observation was necessary and none of them progressed to ulcers or abscesses and therefore no culture and sensitivity tests were performed.

These infiltrates were encountered at an average of 6 months post PKP (SD±2.58, range 2-9 months), most of infiltrates disappeared over the follow up course.

Suture erosions over the nylon sutures were also recorded  in  six  patients  (8%)  throughout  the post operative follow-up period at an average of 10 months (SD±4.69, range 2-15 months). Patients reported a foreign body sensation, the eroding sutures were removed and broad spectrum topical antibiotics were prescribed with close follow up and symptoms disappeared with no sequel on vision.

Three patients presented with broken sutures and leaking wound following trauma, this incidence occurred in keratoconus young patients with age range 13-18 years; however one other patient with graft following psuedophakic bullous keratopathy developed wound dehiscence following suture removal 12 months after surgery, average time from surgery was 10 months (SD±5.56, range 5-8 months).

Discussion

In our study, 6 patients developed suture erosions within an average time of 10 months (±4.69) post surgery, this finding was inconsistent with previous studies published by Dana et al. who reported 33 months,⁽⁷⁾ and Siganos et al. who reported 31.6 months).⁽⁸⁾ This finding is probably related to our policy of removing all sutures between 12-18 months post surgery; as the suture erosion tends to escalate with increased elapsed time from surgery, especially beyond the two year postoperative period.⁽⁷⁾

Suture abscesses occurred at an average of 10 months, this goes with average time reported by Tseng et al.⁽⁹⁾ of 10.4 months, and 8.6 months according to Huang et al.; however suture related abscesses were reported at 21.5 months post surgery according to Leahy et al.,⁽¹¹⁾ and 27.1 months in the study conducted by Sanchez-Perez et al.⁽¹²⁾ The micro organisms reported in the studies performed by Leahy et al.⁽¹¹⁾ and Christo et al.⁽²⁾  were similar to species found in culture results of our study.

Broken  or loose sutures in need for repair occurred only in one patient as it occurred in the early post-operative period; while the patients who presented with loose irritating sutures did not need intervention, because they occurred later in postoperative course, and the tensile strength of the wound was good.

Wound dehiscence after suture removal occurred in one patient (1.3%) while in his study Christo et al.⁽²⁾ reported nine cases (2.5%). Post traumatic wound dehiscence occurred in three patients which was also reported by Lam et al.⁽¹³⁾ they were caused by assault in two patients and due to accidental falling down in the third patient.  Wound dehiscence is a cause for concern  as corneal wounds almost never regain the original strength of the original graft even several years after meticulous repair.⁽¹³⁾

Corneal infiltrates were found in 13.3% of patients at an average of six months, this goes with Brady’s findings,⁽¹⁴⁾ who described suture related immune infiltrates in the early post-operative period. They were multiple, mostly on host side of the graft-host interface with no overlying epithelial defect, and so they were not cultured.

It seems a good policy to remove the sutures between 12-18 months post PKP surgery, as it helps quick rehabilitation and the use of contact lenses with minimal suture related complications.  The frequency of keratoplasty suture erosions and the serious morbidity associated with them dictates that the long term retention of these sutures should be recognized as a risk factor for the development of postoperative infection.⁽⁷⁾

In reviewing patients included in our study, loose irritating sutures necessitating  removal and suture related infiltrates which need close follow up were the most common presenting suture related complications.  These clinical conditions should not be ignored, as delay in management may result in sight threatening complications.

Conclusion

Proper postoperative care is critical for successful PKP. The anticipation of post operative complication in patients is important, and preventative measures should be taken. When complications do occur, prompt and proper management is essential, this will ensure earlier visual rehabilitation and greater long-term graft survival.

References

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