Success Rate of the Zavanelli Maneuver
The Zavanelli maneuver demonstrates a high success rate of approximately 92% (101/110 cases) for achieving delivery in severe shoulder dystocia when conventional maneuvers have failed, though it carries significant risk of neonatal injury including brachial plexus palsy. 1
Overall Success Rates by Indication
Shoulder Dystocia (Primary Indication)
- Success rate: 92% (101/110 cases) in the largest pooled analysis of shoulder dystocia cases where the Zavanelli maneuver was employed 1
- This represents retrospective pooled data from ten case series and 38 individual case reports specifically addressing shoulder dystocia 1
- The maneuver successfully allowed delivery (either vaginally after partial replacement or via cesarean section) in the vast majority of cases where all other conventional maneuvers had failed 1
Other Indications
- Impacted breech presentations: 11 cases reported with successful outcomes 1
- Locked twin deliveries: 11 cases reported with successful resolution 1
- Literature suggests that fetal and neonatal prognosis may be particularly favorable when the Zavanelli maneuver is used for breech presentations compared to shoulder dystocia 2
Clinical Context and Positioning
When the Maneuver is Employed
The Zavanelli maneuver is typically instituted as a last-resort intervention after failure of: 1, 3, 4
- McRoberts maneuver
- Suprapubic pressure
- Wood's corkscrew maneuver
- Posterior arm extraction attempts
- Episiotomy
Modified Technique Success
A modified Zavanelli approach (partial cephalic replacement without immediate cesarean delivery) has been reported to successfully alleviate shoulder dystocia and allow subsequent vaginal delivery 3
- In this variation, the fetal vertex is partially reinserted into the vagina to dislodge impacted shoulders, after which maternal expulsive efforts can complete vaginal delivery 3
Neonatal Outcomes and Complications
Neurological Injury Risk
- Brachial plexus injury (Erb's palsy) can occur even with successful delivery using the Zavanelli maneuver 4
- One reported case of posterior arm shoulder dystocia alleviated by Zavanelli resulted in persistent right Erb's palsy at 3 years of age 4
- The maneuver can be effective even with impacted posterior fetal arm, though neurological injury may be concomitant 4
Overall Safety Profile
- The maneuver is described as "safe and not too difficult to perform even without previous experience" based on analysis of 93 cases in vertex presentations 5
- Fetal and maternal complications are reported as few, though there is acknowledged reporting bias against negative outcomes 5
Critical Training and Implementation Gaps
Lack of Familiarity
- Many clinicians have not had formal training on how to conduct the maneuver and may be unfamiliar with the steps involved 1
- This unfamiliarity leads to reluctance and delay in initiating the procedure when it is needed 1
- Both experienced obstetricians and residents are often fearful when having to use this maneuver and can lose control in cases of shoulder dystocia 5
Cognitive Load Considerations
- The decision to perform the Zavanelli maneuver occurs under extreme time pressure with significant cognitive load on the obstetrician 1
- The rarity of the procedure (few obstetricians have seen it, fewer have performed it) compounds the difficulty of decision-making in these emergencies 5
Practical Recommendation
Every obstetrician should become familiar with the Zavanelli maneuver technique to ensure confidence in its safe use for severe shoulder dystocia cases 5. The high success rate (>90%) when other maneuvers have failed, combined with acceptable safety profile, supports its role as a definitive last-resort intervention before considering more invasive options like symphysiotomy or clavicular fracture 1, 5.