Trephination for Canalicular Obstruction: Experience in 45 Eyes
Bibliographic record
Abstract
PURPOSE: To evaluate efficacy of a trephination procedure for resolution of primary canalicular obstruction or obstruction secondary to failed dacryocystorhinostomy (DCR). METHODS: Retrospective review of patients in a single surgeon's practice who underwent trephination with Crawford tube insertion between 2001 and 2011, with a minimum follow-up period of 12 months. Indications for surgery included symptomatic patients either with primary canalicular obstruction or secondary obstruction after a failed DCR. RESULTS: Trephination was carried out on 45 eyes of 43 patients; 78% were female, and average age at trephination was 61.0 years (range 32 to 89). Thirty-two eyes had previous DCR (75% endonasal, 25% external); mean interval of trephination after DCR was 1.4 years (range 0.3-9.1). Crawford stent tubes were left in-situ in 2 patients; in the remainder, tubes were removed at a mean interval of 5.6 months (range 0.3-20.6). The vast majority of presenting canalicular obstructions were in the common canalicus (73%). Sixteen eyes (36%) underwent a single trephination, and 29 eyes (64%) required repeat intervention; of these, 16 eyes had DCR (3 endonasal, 13 external) and 13 eyes had either repeat trephination with stenting (10 eyes) or repeat stenting alone (3 eyes). When separated into those with primary versus secondary obstruction, re-operation rate was similar in both groups (63% versus 69%). No patients developed complications after trephination. CONCLUSIONS: Trephination is a simple and effective intervention for canalicular obstruction that allowed 64% of patients, through one or two procedures, to avoid the morbidity of DCR.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".