The Analgesic Effects of a Saddle Block with Intrathecal Morphine for Penile-Inversion Vaginoplasty: A Retrospective Study
Bibliographic record
Abstract
Laura Girón-Arango,1â 3 Kyle Robert Kirkham,1â 3 Alexandra L Millman,4â 6 Yonah Krakowsky,4â 6 Yulia Wilk Goldsher,4â 6 Olivia Drodge,5 Qixuan Li,7 Ella Huszti,7 Richard Brull1â 4 1Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada; 2Department of Anesthesia and Pain Management, University Health Network, Toronto, ON, Canada; 3Department of Anesthesia, Womenâs College Hospital, Toronto, ON, Canada; 4Womenâs College Hospital Research Institute, Womenâs College Hospital, Toronto, ON, Canada; 5Transition Related Surgery Program, Womenâs College Hospital, Toronto, ON, Canada; 6Division of Urology, Department of Surgery, University of Toronto, Toronto, ON, Canada; 7Biostatistics Research Unit, University Health Network, Toronto, ON, CanadaCorrespondence: Richard Brull, Department of Anesthesia and Pain Management, Womenâs College Hospital, 76 Grenville St, Toronto, ON, Canada, Email richard.brull@uhn.caBackground: Despite its association with severe postoperative pain, the use of regional anesthesia techniques for penile-inversion vaginoplasty surgery is understudied. This retrospective study aimed to assess the analgesic effects of a saddle block (ultra-low dose hyperbaric spinal anesthesia) with intrathecal (IT) morphine in transgender females undergoing penile inversion vaginoplasty.Methods: We performed a single-centre, retrospective chart review of 72 patients who underwent penile-inversion vaginoplasty with or without saddle block with IT morphine at our institution over a 26-months period. All patients received standard multimodal intravenous analgesia, and the surgeon administered both a pudendal nerve block and a spermatic cord block as part of routine care. Our primary outcome was cumulative opioid consumption (oral morphine equivalent) at 24h postoperatively. Secondary outcomes included postoperative pain severity, duration of stay in the postoperative care unit and in-hospital, time to first opioid request and incidence of opioid- and block-related side effects.Results: 30 patients received a saddle block with IT morphine and 42 patients received standard analgesia. We found no statistical difference in cumulative opioid consumption at 24h postoperatively (control group: 17.7 mg [5.6, 30.8] vs intervention group 12.5 mg [7.5, 22.5] P: 0.249). The addition of a saddle block was associated with clinically and statistically significant improvements in short-term postoperative pain-related outcomes in the recovery room, including mean and maximum pain severity scores, time to first analgesic request, and duration of stay. While no difference in pain scores was detected at the 24-hour time point, mixed-effects modelling demonstrated lower pain trajectories over time among patients in the intervention group, suggesting a time-dependent benefit. However, the significant time-by-group interaction (p = 0.024) indicates that the difference in pain scores between groups decreased over time. We found no differences in the rates of nausea and vomiting between groups. No saddle block procedure-related complications were reported.Conclusion: This retrospective study suggests that despite no statistically significant difference in 24-hour opioid consumption, the addition of a saddle block with 100 mcg of IT morphine is associated with improved PACU pain scores, a longer time to first analgesic request, and a shorter PACU stay. These findings are hypothesis-generating and merit further investigation in a prospective double-blind randomized controlled trial.Keywords: regional anesthesia, transition-related surgeries, acute pain, gender-affirming care
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".