Symptomatic Retethering of the Spinal Cord After Section of a Tight Filum Terminale
Bibliographic record
Abstract
BACKGROUND: Section of a tight filum terminale is a minimally invasive procedure compared with cord untethering procedures used for more complex spinal abnormalities. Anecdotal evidence suggests, however, that the risk of symptomatic retethering resulting from scarring might be higher than previously thought. OBJECTIVE: To determine the frequency of symptomatic retethering after section of a tight filum terminale and to explore possible risk factors. METHODS: We reviewed databases at 2 pediatric neurosurgery centers for all patients who had surgery for a suspected tight filum terminale between January 1982 and June 2009. RESULTS: We identified 152 patients. The median length of follow-up was 78 months. Thirteen patients (8.6%) went on to retether symptomatically at a median time of 23.4 months after the initial procedure. Eight had early retethering (within 2 years) and 5 had late retethering (after 7 years). Compared with late retetherers, early retetherers were older at initial surgery (median, 9.4 vs 0.9 years of age), had a higher level of the conus (median, L1/L2 vs L3/L4), had more arachnoiditis after initial surgery, and required more repeat untethering procedures. Late retetherers were younger at initial surgery than those who did not retether (median, 0.9 vs 4.5 years of age). CONCLUSION: Symptomatic retethering is not uncommon after a simple filum snip, and long-term follow-up is warranted. Two distinct patterns of retethering were observed. Arachnoiditis caused by infection or a cerebrospinal fluid fistula may predispose to early retethering, whereas early surgery for prevention of tethered cord symptoms may predispose to late retethering.
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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 | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".