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Posterior axilla sling traction for shoulder dystocia: case review and a new method of shoulder rotation with the sling

Published:February 28, 2015DOI:https://doi.org/10.1016/j.ajog.2015.02.025

      Objective

      The purpose of this study was to report on all cases in which posterior axilla sling traction (PAST) has been used to deliver cases of intractable shoulder dystocia and to describe a new method of shoulder rotation with the sling.

      Study Design

      A record of all published and known cases was collected that included information on preliminary obstetric techniques that were used and how the PAST technique was performed. Maternal outcomes that included maternal injury and length of hospital stay and fetal outcomes, which included birthweight, Apgar scores, nerve injuries, fractures, hospital stay, and outcome, were documented.

      Results

      We have recorded 19 cases where PAST has been used. In 5 cases, the babies had died in utero. Ten were assisted deliveries. PAST was successful in 18 cases. In one case, it was partially successful because it enabled delivery of the posterior shoulder with digital axillary traction. The most commonly used material was suction tubing. Once the posterior shoulder was delivered, the shoulder dystocia was resolved in all cases. Time from insertion to delivery was <3 minutes when recorded. The birthweights of the infants varied from 3200-4800 g. Posterior arm humerus fractures occurred in 3 cases. There was one case of a permanent Erb’s palsy and 4 cases of transient Erb’s palsies. None were of the posterior arm. During this review, we found that, when direct delivery of the posterior shoulder was difficult because of very severe impaction, the sling could be used to rotate the shoulders easily through 180 degrees assisted by counter pressure on the back of the anterior shoulder. This new method was used in 5 cases and may reduce fetal trauma further during difficult shoulder delivery.

      Conclusion

      This review confirms that PAST can be a lifesaving technique when all another techniques for shoulder dystocia fail. Advantages are that it is easy to use (even by someone who has not seen it used previously), that the sling material is readily available, and that it is inserted quickly with 2 fingers. This is the first report of its use to rotate the posterior shoulder to the anterior position for delivery.

      Key words

      Shoulder dystocia is an unpredictable obstetric emergency; the outcomes rely on quick diagnosis and rapid management.

      Mehta SH, Sokol RJ. Shoulder dystocia: risk factors, predictability, and preventability. Sem Perinatol 2014;38:189-93.

      After the birth of the baby’s head, no further progress takes place; the shoulders usually are entrapped in the anteroposterior diameter of the pelvis. Many techniques have been described for the management of shoulder dystocia; the most common is suprapubic pressure with McRoberts position (hyperflexion of the thighs). If this fails, a number of other maneuvers have been described, which include rotational procedures, maternal position changes, and techniques to deliver the anterior shoulder and arm. Recently, there has been a move towards favoring procedures that enable delivery of the posterior arm.
      • Poggi S.H.
      • Spong C.Y.
      • Allen R.H.
      Prioritizing posterior arm delivery during severe shoulder dystocia.
      Techniques that have been described include delivery of the posterior arm, digital axillary traction, and more recently the posterior axilla sling traction (PAST) procedure.

      Stitely ML, Gherman RB. Shoulder dystocia: management and documentation. Sem Perinatol 2014;38:194-200.

      The PAST technique makes use of a sling that is placed around the posterior axilla. A suction catheter or firm urinary catheter is folded over the operator’s index finger to create a loop (Figure 1). The loop is then fed posteriorly behind the posterior shoulder (Figure 2). The index finger of the operator’s second hand is then used to catch the loop (Figure 3). The loop is pulled through creating a sling around the posterior shoulder (Figure 4). Traction is then applied to the sling to deliver the posterior shoulder (Figure 5). If the posterior arm does not follow, it is then swept out easily because room has been created by delivering the posterior shoulder (Figure 6). If the aforementioned procedure fails, the sling can be used to rotate the shoulders. The sling traction is directed laterally towards the side of the baby’s back then anteriorly while digital pressure is applied behind the anterior shoulder to assist rotation (Figure 7 and Video). Usually once the posterior shoulder is delivered the shoulder dystocia is resolved, and delivery of the baby occurs quickly.
      Figure thumbnail gr1
      Figure 1A suction catheter or firm urinary catheter is folded over the operator’s index finger to create a loop
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      Figure thumbnail gr2
      Figure 2The loop is then fed behind the posterior shoulder with the index finger of 1 hand
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      Figure thumbnail gr3
      Figure 3The operator’s index finger from the other hand is used to pull the loop through
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      Figure thumbnail gr4
      Figure 4A sling is created around the posterior shoulder
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      Figure thumbnail gr5
      Figure 5Traction is applied to the sling to deliver the posterior shoulder
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      Figure thumbnail gr6
      Figure 6Sweeping out the posterior arm with the sling in place
      If the posterior arm does not deliver spontaneously after the posterior shoulder has been delivered, it can be swept out more easily because the delivery of the posterior shoulder creates room for manipulation.
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      Figure thumbnail gr7
      Figure 7Rotation using the sling
      If the posterior shoulder does not deliver with traction on the sling, the sling can be used to rotate the shoulders. The sling is used to rotate the posterior shoulder in the direction shown by the inferior arrow. The operator uses the second hand to apply posterior pressure to the anterior shoulder in the direction shown by the superior arrow.
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      This technique for delivery of the posterior arm with the use of a sling was first described in 2 cases of intractable shoulder dystocia with fetal intrauterine death.
      • Cluver C.A.
      • Hofmeyr G.J.
      Posterior axilla sling traction: a technique for intractable shoulder dystocia.
      An editorial in Obstetrics and Gynaecology recommended that, if it was used, the cases should be documented and published because it is a new technique and because safety and reliability must be confirmed.
      • Gherman R.
      Posterior axillary sling traction: another empiric technique for shoulder dystocia alleviation?.
      In 2009, we published a series of 3 cases.
      • Hofmeyr G.J.
      • Cluver C.A.
      Posterior axilla sling traction for intractable shoulder dystocia.
      We now present a case review of all the cases in which this technique has been used that have been published and reported to us.

      Materials and Methods

      A record of all cases was collected by the authors. Whenever the technique was taught, it was asked that cases be reported to one of the authors, and these cases were included in the review. Information on the maternal age, gravidity, parity, obstetric history, antenatal course, and labor and whether an assisted delivery was performed were collected. All techniques used to attempt to resolve the shoulder dystocia were noted and documented: how the PAST technique was performed, the type of catheter used, the time from insertion to delivery, the designation of the person who performed the technique, and how they learned to perform PAST. Maternal outcomes that included maternal injury and length of hospital stay and neonatal outcomes that included birthweight, 5-minute Apgar scores, nerve injury, fractures, hospital stay, and outcome were documented. If information was incomplete, the original birth attendant was contacted, where possible, to obtain as much missing information as possible. Ethical approval was obtained from the Health Research Ethics Committee at Tygerberg Hospital, Stellenbosch University, Institutional Review Board Number IRB0005239 for the protocol number N14/08/111.

      Results

      We have recorded 19 cases. Most of the women were multiparous; 5 of the women had had a previous cesarean delivery. All of the women were at term gestation; 5 of the babies had died in utero. Four women had had inductions of labor; 11 of them had had assisted deliveries with 10 ventouse deliveries and 1 forceps delivery (Table 1).
      Table 1Maternal characteristics, antenatal course, and labor details
      Cases12345678910111213141516171819
      Age2125342015NANA31NA2035323138NA31NA2424
      Gravidity11221MM222412323131
      Parity00110011301212020
      Gestation38 wkT39 wkTT38 wkTT37 wkT40 wk41 wk 5 d3838 wk 6 dTT42 wk 6 d40 wk 6 d42 wk
      Previous cesarean deliveryYesNoYesYesNoNoNoNoNoYesNoNoYesNoYesNoNoNoNo
      Antenatal complicationsIUFDIUFDNilNilNilDM; IUFDIUFDNilDMNilNilNilIUFDIncreased body mass index; cardiac diseaseNilWolf-Parkinson White syndromeNilNilNil
      Spontaneous laborNoYesYesYesYesYesNAYesYesYesYesNoNoYesYesYesYesYesNo
      Assisted deliveryVVVVVNoNAVNoVNoFNoNoVVNoVNo
      DM, diabetes mellitus; F, forceps; IUFD, intrauterine fetal death; M, multigravid; NA, information not available; T, term; V, ventouse.
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      All of the cases, except one, were severe shoulder dystocia for which other maneuvers had failed to facilitate delivery. In case 11, the operator judged that it was going to be a difficult case and proceeded to the PAST technique after McRoberts and suprapubic pressure failed because she believed that this was the most appropriate technique for the situation. The PAST technique was successful in delivering the posterior shoulder in 18 of the 19 cases. In case 7, the PAST technique was partially successful because it brought the posterior shoulder down low enough to enable digital axillary traction to achieve delivery of the posterior shoulder (Table 2). In this case, a Foley catheter was used that was believed to be too elastic. The most commonly used material for the sling was a suction catheter. Oxygen tubing was used once. A Foley catheter was used 3 times.
      Table 2Techniques used to attempt to resolve the shoulder dystocia
      Cases12345678910111213141516171819
      Mc RobertsUUUUUUUUUUUUUUUUUUU
      Suprapubic pressureUUUUUUUUUUUUUUUUUUU
      Delivery of posterior armUUUUUUUUUUNUUUUUUUU
      Posterior axilla tractionUUUUUUUUUUNUUUUUUNU
      Rotational maneuversUUUUUUUUUUNUUUNUUNN
      Posterior axilla sling tractionSSSSSSPSSSSSSSSSSSSS
      N, not used; PS, partially successful; S, successful; U, unsuccessful.
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      Once the posterior shoulder was delivered, the shoulder dystocia was resolved; in all cases, the original anterior shoulder delivered spontaneously. In cases in which the time from insertion to delivery was reported, it was always <2-3 minutes. The operators included medical officers, midwives, obstetric trainees, consultants, and the authors (Table 3).
      Table 3Posterior axilla sling traction technique
      Variable12345678910111213141516171819
      Sling materialSCSCSCSCSCOTFoleysFoleysSCSCSCSCSCSCSCSCSCSCSC
      Size (French)1414121414IUIUIU1414IUIUIU10IU12141012
      Easy insertionYesYesYesYesYesYesYesYesYesYesYesYesYesYesYesYesYesYesYes
      Posterior shoulder delivered with posterior axilla sling tractionYesYesYesYesYesYesPosterior axilla sling traction then digital axilla tractionYesYesYesYesYesYesYesYesYesYesYesYes
      Spontaneous posterior arm delivery after posterior axilla sling tractionYesNo post arm swept downNo post arm swept downNo post arm swept downNo post shoulder rotated with posterior axilla sling traction delivered as ant shoulderYesYesYesYesNo post arm swept down digitallyYesYesYesNo post shoulder rotated with posterior axilla sling traction delivered as ant shoulderYesNo post shoulder rotated with posterior axilla sling traction delivered as ant shoulderNo post shoulder rotated with posterior axilla sling traction delivered as ant shoulderYesNo post shoulder rotated with posterior axilla sling traction delivered as ant shoulder
      Spontaneous delivery of anterior shoulderYesYesYesYesYes delivered as post shoulderYesYesYesYesYesYesYesYesYes delivered as post shoulderYesYes delivered as post shoulderYes delivered as post shoulderYesYes
      Spontaneous anterior arm deliveryYesYesYesYesYes delivered as post armYesYesYesYesYesYesYesYesYes delivered as post armYesYes delivered as post armYes delivered as post armYesYes delivered as post arm
      Time from insertion to delivery (min)232IUIUIUIU33IUIU22222322
      Designation of person using posterior axilla sling tractionAAAAAMOObTObTMOAMObTAAAAAObTOb T and A
      How did they learn posterior axilla sling tractionNANANANANAPPPPNATPNANANANANAPNA
      A, authors; ant, anterior; IU, information unavailable; M, midwife; MO, medical officer; NA, not applicable; ObT, obstetric trainee; OT, oxygen tubing; P, presentation; SC, suction catheter; T, tutorial.
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      One case was complicated by postpartum hemorrhage that was associated with a posterior vaginal tear. In 3 cases, episiotomies were performed; in 1 case, a second-degree tear occurred. There was 1 third-degree tear (Table 4).
      Table 4Maternal outcomes
      Variable12345678910111213141516171819
      Maternal injuryNoneNonePostpartum hemorrhage after vaginal tearNoneNoneLarge episiotomyNoneEpisiotomyIUIUEpisiotomy2nd-degree tearNoneNoneNoneNoneNone3rd-degree tearNone
      Maternal hospital stay, d211112IU4IUIU132111131
      IU, information unavailable.
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.
      The birthweights of the infants varied from 3200-4800 g, with 7 at >4000 g. There were 3 posterior arm humerus fractures that occurred after the PAST technique had been used to deliver the shoulder and the posterior arm was swept down and out digitally, which indicated how tightly the arms were impacted. There was 1 case of a permanent Erb’s palsy of the anterior arm and 4 cases of transient Erb’s palsies of the anterior arm. There were no cases of Erb’s palsies of the posterior arm (Table 5).
      Table 5Neonatal outcomes
      Variable12345678910111213141516171819
      Birthweight, g3200IU3720342036904200IUIU44003420440043002852480030984020389045484144
      5-min APGAR scoreIUFDIUFD827IUFDIUFD39286IUFD559699
      FracturesPosterior humerusNoneNonePosterior humerusNoneNoneNoneNoneNonePosterior humerusNoneNoneNoneNoneNoneNoneNoneNoneNone
      Nerve injuryNANATransient Erb’s palsy of anterior armTransient Erb’s palsy of anterior armTransient Erb’s palsy of anterior armNANANoneNoneTransient Erb’s palsy of anterior armNoneErb’s palsy of anterior armNANoneNoneNoneNoneNoneNone
      Hospital stay, dNANAIU85NANA12IU804NA0IU0001
      OutcomeNANAFull recoveryHead cooling, full recoveryGoodNANAIntubated and cardiopulmonary resuscitation; seizures at 2 hrGoodSpontaneous breathing at 6 min, head coolingGoodOutpatient follow upNAGoodHead cooling, good outcomeGoodGoodGoodGood
      IU, information unavailable; IUFD, intrauterine fetal death; NA, not applicable.
      Cluver. PAST or rotation for shoulder dystocia. Am J Obstet Gynecol 2015.

      A new method of shoulder rotation with the posterior axilla sling

      During the course of this review, one of the authors (G.J.H.) found that, if the posterior shoulder could not easily be brought down posteriorly, the sling could be used to rotate the shoulders. This was achieved by altering the direction of traction to lateral traction in the direction of the baby’s back, assisted by pressure behind the anterior shoulder in the opposite direction with 2 fingers. As the shoulders rotated, the direction of sling traction was altered through an arc of 180 degrees to remain at right angles to the axis of the shoulders. This method was repeated successfully in 4 subsequent cases.

      Comment

      This review confirms that shoulder dystocia is an unpredictable condition and that having an additional technique at one’s disposal when all other techniques fail can be of great benefit. Avoiding last resort cesarean delivery is beneficial both for the mother as she avoids emergency surgery and for the fetus because the time taken to get to delivery theater may compromise oxygenation and long-term outcome.
      Advantages of this technique are that it is easy to use, the material used for the sling (such as an infant suction catheter) is readily available, and it can be inserted with 2 index fingers, which is very advantageous in a narrow pelvis. The catheter material ideally should be inelastic, such as a plastic suction catheter or oxygen tubing. A Foley catheter is more difficult to use because it stretches when traction is applied. The catheter loop can be left as a double loop or pulled through to create a single loop around the axilla. Another advantage of the PAST technique that is identified in this review is that it can be used to rotate the shoulders with digital pressure on the posterior aspect of the anterior shoulder if initial downward traction does not facilitate delivery. This has not been reported previously. Further research is needed to determine whether this may be the preferable method of delivery. Our impression is that the arm is delivered more easily by rotation to the anterior position than sweeping out the posterior arm, after direct delivery of the shoulder, particularly when the arm is very tightly impacted.
      Complicated shoulder dystocia often is associated with injury to the baby. In our review, there were 3 cases of humerus fractures that all recovered well with conservative management. The occurrence of fractures during the extraction of the posterior arm, after the PAST technique had been used, is an indication of the degree of impaction of these cases that had been undeliverable by standard techniques. Brachial plexus injury is always a concern with severe shoulder dystocia. In our review, there was 1 case of a permanent Erb’s palsy and 4 cases of transient Erb’s palsies. All of these were of the anterior shoulder and not the posterior shoulder where the catheter was inserted. It is likely that these occurred before the application of the PAST technique, because of initial attempts to deliver the anterior shoulder by posterior head traction.
      The simplicity of the technique is attested to by the fact that, in 4 cases, the technique was performed by trainees; in 2 cases, the technique was performed by medical officers, and, in 1 case, the technique was performed by a midwife who worked in a primary care clinic. None of the operators had seen the technique being performed, and they all learned about the procedure from tutorials or Power Point (Microsoft Corporation, Redmond, WA) presentations.
      This case review indicates that this can be a lifesaving technique with benefits for both the mother and child and that more health care practitioners should be aware of this new technique. This is still a new technique, and until more safety data are available, it should be reserved for cases in which other commonly used techniques have failed.

      Acknowledgments

      We thank Nicole Krzys, Petro Wippelinger, Matthew Gooding, Renardo Lourens, Anna Limgenco, Ritche Dalmacio, Eckhart Buchman, Kate Tyson, and Ndumi Mkontwana for providing information about the cases in which the PAST technique was used.

      Supplementary data

      References

      1. Mehta SH, Sokol RJ. Shoulder dystocia: risk factors, predictability, and preventability. Sem Perinatol 2014;38:189-93.

        • Poggi S.H.
        • Spong C.Y.
        • Allen R.H.
        Prioritizing posterior arm delivery during severe shoulder dystocia.
        Obstet Gynecol. 2003; 101: 1068-1072
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        • Hofmeyr G.J.
        Posterior axilla sling traction: a technique for intractable shoulder dystocia.
        Obstet Gynecol. 2009; 113: 486-488
        • Gherman R.
        Posterior axillary sling traction: another empiric technique for shoulder dystocia alleviation?.
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        • Cluver C.A.
        Posterior axilla sling traction for intractable shoulder dystocia.
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