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Journal Club

Tumor/Skull Base

Results of a prospective multicenter controlled study comparing surgical outcomes of microscopic versus fully endoscopic transsphenoidal surgery for nonfunctioning pituitary adenomas: the Transsphenoidal Extent of Resection (TRANSSPHER) Study

Journal of Neurosurgery | 2020

Rapid review note

Journal Club is a rapid, AI-assisted appraisal layer. It highlights study design, effect estimates, and practice relevance, but it is still a briefing, not a replacement for the paper.

For education only. Not medical advice.

Paper snapshot

Rapid study overview

Open paper

DOI

10.3171/2018.11.JNS181238

PMID

N/A

PICO

Population

Adults with nonfunctioning pituitary adenomas undergoing transsphenoidal surgery at 7 pituitary centers; 260 patients were enrolled.

Intervention

Fully endoscopic transsphenoidal surgery.

Comparator

Microscopic transsphenoidal surgery.

Outcomes

Gross-total resection on postoperative MRI, volumetric extent of resection, new pituitary hormone deficiency, and standard quality metrics.

Design

Type

Prospective multicenter controlled cohort trial

Randomized

No

Multicenter

Yes

Blinded

MRI reviewers were blinded to treatment group

Follow-up

6 months for endocrine outcomes

Primary endpoint

Gross-total resection determined by postoperative MRI.

Secondary endpoints

  • Volumetric extent of resection
  • Pituitary hormone outcomes
  • Operative duration, readmission, and length of stay

Practice impact

What this means

TRANSSPHER says the microscopy-versus-endoscopy argument is not mainly about gross-total resection. Resection rates were similar, but postoperative pituitary dysfunction was lower with endoscopy. The practical message is that endoscopy looks attractive when a center is already good at it, but this study does not prove that it is universally superior for every pituitary surgeon.

Bottom line

For nonfunctioning pituitary adenomas, fully endoscopic surgery did not clearly improve resection rates over microscopy, but it may reduce new postoperative pituitary dysfunction when performed in experienced centers.

Strength of evidence

moderate

Recommendation

consider change

Why it matters

  • The primary resection endpoint was neutral, so this is not a clear superiority trial for endoscopy.
  • The endocrine signal materially favored endoscopy and is clinically relevant.
  • Nonrandom technique assignment and experience imbalance prevent a stronger recommendation.

What would change my mind

  • A randomized or well-matched comparative study confirming that the endocrine advantage persists after balancing tumor complexity and surgeon experience.
  • Consistent multicenter data showing no real hormone difference once learning-curve effects are removed.

Critical appraisal

How strong is the paper?

Methods critique

Risk of bias

This was a prospective but nonrandomized comparison, so surgeon and center preference determined technique and left the study open to treatment-selection bias.

Confounding

Microscopic surgeons were more experienced than endoscopic surgeons, and the paper notes imbalances such as more symptomatic and previously operated tumors in the microscopic group.

Missing data

Although 260 patients were enrolled, fewer contributed to some endpoint analyses, which suggests missing MRI or endocrine follow-up for part of the cohort.

Multiplicity

The study tested several secondary surgical and endocrine outcomes without presenting a formal multiplicity correction, so secondary wins should be interpreted cautiously.

Notes

  • Seven centers and 15 surgeons participated, which improves practice relevance.
  • The study was powered for a resection advantage that it did not find.
  • The most clinically meaningful difference favored endoscopy on postoperative pituitary function, not gross-total resection.

Stats check

NNT

Approximate NNT 5 to avoid 1 new hormone deficiency.

Effect sizes

  • Gross-total resection was 83.7% with endoscopy versus 80.0% with microscopy (OR 0.8, 95% CI 0.4-1.6; p=0.47).
  • New hormone deficiency at 6 months was 9.7% after endoscopy versus 28.4% after microscopy (OR 3.7, 95% CI 1.7-7.7; p<0.001).
  • Microscopic cases were significantly shorter in duration than endoscopic cases (p<0.001).

Absolute effects

  • Gross-total resection occurred in 139 of 166 endoscopic cases versus 60 of 75 microscopic cases.
  • New hormone deficiency occurred in 14 of 145 endoscopic patients versus 19 of 67 microscopic patients with 6-month endocrine data.
  • Length of stay, surgery-related deaths, and unplanned readmissions were similar between groups.

Concerns

  • Because technique choice was not randomized, the endocrine difference may still reflect case selection or surgeon factors.
  • The study was underenrolled relative to its original target and may have been underpowered for smaller resection differences.
  • Direct comparison of learning-curve techniques is difficult when surgeon experience differs by arm.

External validity

Who it applies to

Adults with nonfunctioning pituitary adenomas treated at experienced pituitary centers capable of either microscopic or fully endoscopic surgery.

Who it does not

Patients with pituitary apoplexy, other sellar lesions, or settings where only one approach is routinely performed well.

Generalizability notes

  • The multicenter design improves transportability to specialized pituitary programs.
  • Results may not translate to low-volume surgeons or centers early in the endoscopic learning curve.
  • The paper is most helpful when both techniques are technically available options.

Evidence trace

Source trace and metadata

Citations (5)

claim_id

methods_critique.risk_of_bias

locator

p. 1

claim_id

methods_critique.confounding

locator

p. 9

claim_id

stats_check.effect_sizes

locator

p. 1

claim_id

stats_check.absolute_effects

locator

p. 1

claim_id

practice_impact.bottom_line

locator

p. 1

Metadata

Generated at

2026-03-08T16:15:00-05:00

Version

manual-pdf-repair-v1