Comparison of magnitude and summated vector mean of surgically induced astigmatism vector according to incision site after phakic intraocular lens implantation

Background

To compare the arithmetic mean (M-SIA) and the summated vector mean of surgically induced astigmatism (SVM-SIA) according to the incision site after phakic intraocular lens (Visian implantable collamer lens (ICL), STAAR Surgical) implantation.

Methods

This study comprised 121 eyes of 121 consecutive patients undergoing ICL surgery through a 3.0-mm temporal or superior clear corneal incision. The magnitude and the axis of corneal astigmatism preoperatively and 3 months postoperatively were measured using an automated keratometer. The M-SIA and the SVM-SIA were determined according to the incision site.

Results

The magnitude of corneal astigmatism significantly increased from 1.23 ± 0.59 D preoperatively to 1.46 ± 0.72 D postoperatively in the temporal incision group (Wilcoxon signed-rank test, P < 0.001), but it significantly decreased from 1.09 ± 0.36 D preoperatively to 0.86 ± 0.41 D postoperatively in the superior incision group (P < 0.001). The M-SIA was 0.48 ± 0.30 D, and the SVM-SIA was 0.23 ± 0.52 D at a meridian of 82° in the temporal incision group. The M-SIA was 0.57 ± 0.30 D, and the SVM-SIA was 0.47 ± 0.45 D at a meridian of 1° in the superior incision group.

Conclusions

ICL implantation induces the M-SIA by approximately 0.5 D, but the SVM-SIA decreased to 50% and 80% of the M-SIA in magnitude through temporal and superior incisions, respectively. The direction of the SVM-SIA showed a tendency toward corneal flattening to the incisional site. It should be noted that the M-SIA is somewhat different from the SVM-SIA according to the incision site.

Trial registration University Hospital Medical Information Network Clinical Trial Registry (000044269)

Resection of carcinoma of the external auditory canal in a patient with a high jugular bulb using temporal craniotomy

External auditory canal (EAC) carcinoma is a rare and unusual malignancy. The complex anatomy and relationship between the tumor and surrounding tissues in a limited space render it difficult to attain safe resection margins during surgery. A high jugular bulb (HJB) is one such anatomical variation that has important surgical implications that complicate the surgical procedure for EAC carcinoma. A 73-year-old woman presented with a 3-month history of right ear pain. Pathological findings and computed tomography (CT) revealed EAC carcinoma, which was expanding to the middle ear (ME). Although there was no cavity inside the ME, an HJB was detected. Surgical treatment using a temporal incision for temporal craniotomy achieved complete resection of the tumor and preserved facial nerve function. The patient recovered without complications and was discharged 17 days after the operation. Temporal incision and temporal craniotomy is a useful approach for EAC carcinoma with HJB.

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