Is the Formation of a Bladder Flap at CesareanNecessary? A Randomized Trial

M. Hohlagschwandtner, MD, E. Ruecklinger, PhD, P. Husslein, MD, and E. A. Joura, MD

OBJECTIVE: To evaluate the effects of not forming a blad-der flap at lower-segment cesarean delivery.

METHODS: A total of 102 women who underwent cesareandelivery were prospectively randomized to one of twogroups. In the study group (n � 53), a cesarean was per-formed without formation of a bladder flap. In the controlgroup (n � 49), cesarean was performed with formation ofa bladder flap before the uterine incision.

RESULTS: There were differences of median skin incision-delivery interval (5 versus 7 minutes, P < .001), mediantotal operating time (35 versus 40 minutes, P � .004), andmedian blood loss (� hemoglobin 0.5 versus 1 g/dL, P �.009) in favor of the study group. Postoperative microhe-maturia was reduced in the study group (21% versus 47%,P < .01). The median need for analgesics was reduced inthe study group (75.0 mg diclofenac versus 150.0 mg, P <.001), and there was a lower percentage of patients receiv-ing analgesics 2 or more days after cesarean in the studygroup (26.4% versus 55.1%, P � .006). There was no differ-ence in bowel function.

CONCLUSION: Omission of the bladder flap provides short-term advantages such as reduction of operating time andincision-delivery interval, reduced blood loss, and need foranalgesics. Long-term effects remain to be evaluated.(Obstet Gynecol 2001;98:1089–92. © 2001 by the Ameri-can College of Obstetricians and Gynecologists.)

Creation of the bladder flap is a standard part of cesareantechnique.1 It has yet to be established whether there is anyadvantage in dissecting the urinary bladder from the lowersegment of the uterus. Many studies2–6 have demonstratedthat simplification of cesarean delivery may lead to a signif-icant decrease in operating time, postoperative febrile mor-bidity, and hospital costs. Wood et al6 demonstrated noadverse effect from a simplified method of cesarean (Pelosi-Type), which included the omission of bladder dissectiontogether with other modifications. To our knowledge, thisis the only report6 on the elimination of the bladder dissec-tion in cesarean delivery, but these authors did not investi-gate this single modification.

Based on these observations, we conducted a prospec-tive randomized trial to evaluate short-term effects of theomission of the bladder flap.

MATERIALS AND METHODS

A total of 102 women, who underwent cesarean deliveryin the Department of Obstetrics at the University Hos-pital of Vienna between January and May 2000, wereincluded in the study. There were no significant differ-ences between the groups with respect to maternal andgestational age. All participating women were white, andinformed consent was obtained in all cases. The studywas performed in accordance with the ethical standardsfor human experimentation established by the Declara-tion of Helsinki of 1975, revised 1983. Exclusion criteriawere fetal malformations and previous surgery on theuterus. During the observation period, 255 women wereeligible for recruitment, but not all obstetricians on callparticipated in the study. Randomization was performedwith a computer-based program (zero/one system). Be-fore entering the operating room, the obstetrician took asealed envelope containing the randomization numberand the mode of cesarean delivery. In the study group,low-segment cesarean delivery was performed in thefollowing way: the abdomen was opened with a Pfan-nenstiel incision, and a low-transverse uterine incisionwas performed about 1 cm above the vesicouterineperitoneal fold, without dissection and formation of abladder flap (Figure 1). After the delivery of the fetus andthe placenta without cord traction or manual removal,the uterine incision was closed in one layer (Vicryl 1,CTX plus, Figure 2). The visceral and parietal perito-neum were not sutured, and the rectus sheath was closedin a continuous fashion (Vicryl 1, CT-1). The subcuta-neous fat was closed if the thickness was more than 2 cm,followed by skin closure (all suture material by Ethicon,Norderstedt, Germany).

In the control group, cesarean delivery was performed inthe same way together with formation of a bladder flapbefore the uterine incision.4 All surgical procedures wereperformed by resident medical staff, who were not aware of

From the Department of Obstetrics and Gynecology, University of Vienna (AKH),Vienna, Austria.

1089VOL. 98, NO. 6, DECEMBER 2001 0029-7844/01/$20.00© 2001 by The American College of Obstetricians and Gynecologists. Published by Elsevier Science Inc. PII S0029-7844(01)01570-8

the parameters being measured. All patients were ad-ministered 10 IU oxytocin and prophylactic antibioticsafter cord clamping. All women were offered solid foodwithin 8 hours after cesarean delivery. The standardpostoperative analgesic drug was diclofenac (NovartisPharma, Vienna, Austria) administered according to thewomen’s requirements, either intravenously or as a sup-pository.

The following parameters were evaluated: total oper-ating time (from skin incision to closure of the skin), skinincision-delivery time, pre- and postoperative (obtainedon the first day after delivery) hemoglobin levels, pre-and postoperative (first day after delivery) urine test forblood (dip stick “Combur,” Bohringer, Mannheim, Ger-many), febrile morbidity (defined as two separate epi-sodes of fever greater than or equal to 38C for 2 or moredays postoperatively), postoperative need of analgesics,and bowel function defined as postoperative day of first

defecation, wound healing, hospitalization days, and read-missions. The ward staff was unaware of the type of surgi-cal technique. Obstetric (gestational age, indication for ce-sarean section) and neonatal indicators (birth weight, pH ofthe umbilical cord, Apgar score) were recorded.

A review of the first 50 patients revealed the favorabletrends for operating time of a power of 0.8. Further inquiryconfirmed primary trends. The Kolmogorov-Smirnov testwas used to determine variables without normal distribu-tion. For comparison of patients with formation of a blad-der flap versus patients without formation of a bladder flap,the Student t test was applied. The Mann-Whitney U testwas applied for variables, where the normal distributionwas questionable. Spearman’s correlation coefficient de-scribes associations between operating time and � hemo-globin. Independent dichotomous variables were tested bythe �2 test and Yates’ continuity correction. Frequencieswere quoted with 95% confidence intervals (CI), whichwere calculated by the exact method. All statistical testswere executed two-tailed. Because we did an interimanalysis, which was the basis for sample size estimates, Pvalues below .025 were considered significant. Statisticalanalyses were performed by the use of SPSS (SPSS Inc.,Chicago, IL) for Windows 8.0 (1997).

RESULTS

Statistical analyses compared the characteristics and vari-ables of 53 patients in whom the formation of the bladderflap was omitted with those of 49 patients with a stan-dard bladder flap formation. Table 1 lists patient charac-teristics and obstetric data. The indications for cesareandelivery are shown in Table 2. The distribution ofindividual surgeons between the two groups was similar.

There were significant differences in skin incision-delivery interval, total operating time, and � hemoglobinin favor of the study group (Table 3). There was asignificant correlation between the total operating timeand � hemoglobin. Spearman’s coefficient amountedrs � 0.260 (P � .008). No woman had microhematuriabefore cesarean. Microhematuria was observed in 46.9%(exact 95% CI 32.5%, 61.7%) in the control group and in20.8% (exact 95% CI 10.8%, 34.1%) in the study group(P � .010). The need for analgesics was reduced in thestudy group (Table 3). The percentage of patients receiv-ing analgesics 2 or more days after cesarean was 26.4%(95% CI 15.3%, 40.3%) in the study group and 55.1% inthe control group (95% CI 40.2%, 69.3%, �2, P � .006).There was no difference in bowel function between thetwo groups (Table 3). In the study group, 62.3% ofwomen (95% CI 47.9%, 75.2%) had the first defecation atthe first postoperative day, and 49.0% (95% CI 34.4%,63.7%, �2, P � .250) in the controls.

Figure 1. Uterine incision without bladder dissection. In-cision is made 1 cm above the vesicouterine peritoneal fold(elective cesarean delivery at term, UB � urinary bladder).Hohlagschwandtner. Bladder Flap and Cesarean Delivery. Obstet Gynecol 2001.

Figure 2. Exteriorized uterus after repair. Note the de-scended urinary bladder in absence of any bleeding (UB �urinary bladder).Hohlagschwandtner. Bladder Flap and Cesarean Delivery. Obstet Gynecol 2001.

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During the postoperative course, one woman in eachgroup developed fever associated with retained placentalfragments. Those patients underwent dilation and evac-uation. No cases of wound infection or wound dehis-cence occurred. The median hospitalization time was 6days in both groups, and no readmissions were observedin both groups.

There were no significant differences between the groupswith respect to Apgar score and the arterial pH value.

DISCUSSION

This study examines whether there are any short-termbenefits in eliminating the bladder flap at cesarean deliv-ery. The creation of a bladder flap and its repair dates tothe preantibiotic era,6 when it was employed to protectthe peritoneal cavity from intrauterine infection. Closureof the visceral peritoneum remained a clinical standardprocedure,1 even though there are no advantages.3

Our findings indicate that cesarean delivery withoutthe formation of a bladder flap provides a number ofsignificant short-term benefits. Several points need to beaddressed: firstly, the level of the uterine incision (Figure

1). In this setting, some obstetricians consider the uterineincision may be too high in a thicker portion of theuterus. In all cases in both groups, the incision was madeessentially at the same level in the lower segment belowthe uterine physiologic retraction ring. In addition, theomission of the bladder flap prevents the incision frombeing made too low. Low uterine incision should beavoided when the cervix is fully effaced and dilated toprevent rupture of the cervix. Because the omission ofthe bladder flap is a new modification, there are nolong-term data relating to future pregnancies. Furtherstudies are required to investigate the safety of thistechnique with respect to subsequent pregnancies andtrial of labor. A further point of discussion is the deliveryof the infant. Throughout the study period, no problemswere encountered in either group.

It is important to consider that the anatomic situationis the same whether the bladder flap is created actively ornot. If the uterine incision is made slightly above thevesicouterine peritoneal fold, the loose connective tissuebetween the uterus and the urinary bladder allows thespontaneous descent of the bladder (Figure 2). Duringthis process, no vascular injury occurs. This may havecontributed to the decreased blood loss in the studygroup. Blood loss increases the risk of postoperativecomplications, including infection.7 Because the omis-sion of the bladder flap causes less trauma and vascularinjury, subsequently fewer additional hemostatic suturesare required. This is associated with a decreased operat-ing time in the study group. Recently, a short operatingtime was shown to reduce the risk of developing mildileus symptoms in early-fed women after cesarean.8 Thereduced need for analgesic drugs probably also reflectsthe reduced trauma. The median hospital stay of morethan 6 days results from the European reimbursementsystem and should be considered by American readers.The rate of retained placental fragments (one in eachgroup), higher than in other series,3,4 is unexplained.

Bladder injuries are rare complications of cesarean

Table 1. Patient Characteristics and Obstetric Data

Study group(n � 53)

Control group(n � 49) Significance

Maternal age (y) 30 (19–41) 29 (19–46) NSParity

Primiparous 30 (57%) 27 (55%) NSMultiparous 23 (43%) 22 (45%) NS

Gestational age (wk) 38 (27–42) 38 (27–42) NSBirth weight (g) 2950 (1012–4240) 3040 (1140–4370) NSFetal presentation

Vertex 43 (81%) 38 (78%) NSBreech 10 (19%) 11 (22%) NS

NS � not significant.Values are given in median and range.

Table 2. Indications for Cesarean Delivery

Study group(n � 53)

Control group(n � 49) Significance

Breechpresentation

8 (15.0) 9 (18.4) NS

PROM 3 (5.6) 3 (6.1) NSCPD 7 (13.1) 2 (4.1) NSPIH, HELLP 3 (5.6) 0 (0) NSSGA 1 (1.8) 0 (0) NSArrest of labor 3 (5.6) 3 (6.1) NSFetal distress 14 (26.4) 15 (30.6) NSOthers 14 (26.4) 17 (34.7) NSNS � not significant; PROM � premature rupture of the membranes;CPD � cranial-pelvic disproportion; PIH � pregnancy-induced hyper-tension; HELLP � hemolysis, elevated liver enzymes, low platelets;SGA � small for gestational age.

Values are quoted in %.

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and were not observed in the study group. These find-ings are in accordance with the results of Wood et al.6

When bladder injury occurs, it is usually caused bysurgical difficulty encountered while developing thebladder flap.9 The low incidence of 0.14–0.31%9,10 re-quires a large number (n � 40,000) of investigatedcesareans to draw valid conclusions with respect to ma-jor bladder injuries. The lower rate of postoperativemicrohematuria also reflects a reduced manipulation andtrauma of the urinary bladder.

Long-term effects, such as adhesions and fertility,remain to be evaluated. Bowel obstruction and paincaused by adhesions are rare after cesarean delivery. In astudy by Al-Took et al,11 the incidence of small bowelobstruction after cesarean delivery (five of 100,000 ce-sarean deliveries) was significantly less than after otherabdominal operations. We observed no postoperativeileus among the study population. The practice of non-closure of the peritoneum does not appear to promoteadhesions.12 We are carefully following up all women ofthe study population. One year after completing thestudy, six women (three of each group) have presentedpregnant at our department. One woman had a repeatcesarean for breech presentation, and another woman aspontaneous vaginal delivery. One fetus with an ompha-locele suffered an intrauterine death in the 20th week ofpregnancy. After the favorable results from the study,routine creation of a bladder flap is now omitted in ourinstitution. Long-term results on a larger scale are underevaluation and will be reported.

In conclusion, the results of the present study demon-strate that the omission of the bladder flap provides short-term benefits such as reduction of operating time andincision-delivery interval, reduced blood loss, and reducedneed for analgesics. Long-term effects remain to be evalu-ated.

REFERENCES

1. Cesarean delivery and cesarean hysterectomy. In: Cun-ningham FG, MacDonald PC, Cant NF, Levono KJ, Gil-

strap LC III. Williams obstetrics. 20th ed. Norwalk, CT:Appleton & Lange, 1997:517.

2. Hauth JC, Owen J, Davis RO. Transverse uterine incisionclosure: One versus two layers. Am J Obstet Gynecol1992;167:1108–11.

3. Nagele F, Karas H, Spitzer D, Staudach A, Karasegh S, BeckA, et al. Closure or nonclosure of the visceral peritoneum atcesarean delivery. Am J Obstet Gynecol 1996;174:1366–70.

4. Joura EA, Yucel Y, Zeisler H, Seifert M, Chalubinski K,Husslein P. Minimal wound closure at cesarean delivery.Geburtsh Frauenheilkd 1998;58:651–3.

5. Holmgren G, Sjoholm L, Stark M. The Misgav Ladachmethod for cesarean section: Method description. ActaObstet Gynecol Scand 1999;78:615–21.

6. Wood RM, Simon H, Oz Ali-Utku. Pelosi-Type vs. tradi-tional cesarean delivery. A prospective comparison. JReprod Med 1999;44:788–95.

7. Tran TS, Jamulitrat S, Chongsuvivatwong V, Geater A.Risk factors for postcesarean surgical site infection. ObstetGynecol 2000;95:367–71.

8. Patolia DS, Hilliard RLM, Toy EC, Baker B. Early feedingafter cesarean: Randomized trial. Obstet Gynecol 2001;98:113–6.

9. Eisenkop SM, Richman R, Platt LD, Paul RH. Urinarytract injury during cesarean section. Obstet Gynecol 1982;60:591–6.

10. Rajasekar D, Hall M. Urinary tract injuries during obstet-ric intervention. Br J Obstet Gynaecol 1997;104:731–4.

11. Al-Took S, Platt R, Tulandi T. Adhesion-related small-bowel obstruction after gynecologic operations. Am JObstet Gynecol 1999;180:313–5.

12. Joura EA, Nather A, Husslein P. Non-closure of perito-neum and adhesions: The repeat cesarean section. ActaObstet Gynecol Scand 2001;80:286.

Address reprint requests to: M. Hohlagschwandtner, MD,Department of Obstetrics and Gynecology, University Hospi-tal of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Aus-tria; E-mail: maria.hohlagschwandtner@akh-wien.ac.at.

Received February 6, 2001. Received in revised form July 31, 2001.Accepted August 2, 2001.

Table 3. Incision-Delivery Interval, Total Operating Time, Change in Hemoglobin, Postoperative Need of Diclofenac, andBowel Function in the Two Study Groups

Study group(n � 53)

Control group(n � 49)

Significance(P value)

Incision-delivery interval (min) 5 (1–10) 7 (2–14) .001*Total operating time (min) 35 (12–50) 40 (20–58) .004*�Hemoglobin (g/dL) 0.5 (0.0–2.6) 1.0 (0.0–2.7) .009†

Need of diclofenac (mg) 75 (0–300) 150 (0–375) .001†

Postoperative day of first defecation 1 (1–3) 2 (1–5) .188†

Values are given as median and range.* P values are results of the Student t test.† P values are results of the Mann-Whitney U test.

1092 Hohlagschwandtner et al Bladder Flap and Cesarean Delivery OBSTETRICS & GYNECOLOGY