Background
Surgical site infections (SSIs) are an important cause of morbidity following cesarean delivery, particularly in obese patients. Methods to reduce SSIs after cesarean delivery would have an important impact in obese obstetric patients.
Objective
The purpose of this study was to determine whether the Alexis O cesarean delivery retractor, a barrier self-retaining retractor, reduces SSIs and wound disruptions in obese patients undergoing cesarean delivery.
Study Design
This was a randomized controlled trial of obese women (body mass index ≥ 30 kg/m 2 ) undergoing nonemergent cesarean delivery. Patients were randomized to the treatment group (using the Alexis O cesarean delivery retractor) or to the control group (using conventional handheld retractors). The primary outcome was SSI or wound disruption during the 30 day postoperative period. Secondary outcomes included operative time, estimated blood loss, change in hemoglobin, antiemetic use, length of postoperative hospital stay, hospital readmission, and other postoperative complications.
Results
A total of 301 patients were enrolled in the study. One hundred forty-four patients were randomized to the treatment group and 157 to the control group. Baseline characteristics and indications for cesarean delivery were similar between the 2 groups. Median body mass index was 40.1 kg/m 2 . There were no significant differences between the treatment and the control group in the primary outcome of SSI or wound disruption rates at the 30 day assessment (20.6% vs 17.6%, P = .62), during the postoperative inpatient hospitalization or at the 1–2 week postoperative visit. There were also no differences in the primary outcome when adjusting for obesity class or thickness of the subcuticular layer. Patients in the treatment group had lower rates of uterine exteriorization (54.3% vs 87.3%, P < .001), but there were no differences in all other outcomes.
Conclusion
Use of the Alexis retractor in cesarean delivery deliveries did not decrease SSI or wound disruption rates in an obese population. Its use as a retractor should be left to the discretion of the surgeon and clinical circumstances.
Surgical site infections (SSIs) and wound disruptions are important causes of postoperative morbidity following cesarean delivery, estimated to occur between 3% and 30%, depending on the population studied, definition used, and length of time patients are followed up. Morbidities include increased hospital stay and readmissions, health care costs, emotional stress, and decreased productivity.
Obesity is one of the most important risk factors associated with the development of wound complications. Importantly, the risk increases with advancing body mass index (BMI) to an incidence as high as 30% in the massively obese patient (BMI ≥ 50 kg/m 2 ). Strategies to prevent wound complications after cesarean delivery, particularly in populations at high risk, would have important health care implications and should be a goal of obstetric care.
Wound protectors are designed to act as a form of barrier protection, while also retracting wound edges, during surgical procedures. The Alexis wound retractor (Applied Medical, Rancho Santa Margarita, CA) consists of 2 plastic rings joined by an impervious plastic sheath, providing circumferential retraction and wound protection to the abdominal wall edges during surgery. Previous studies have shown decreased rates of SSIs associated with the use of the Alexis wound retractor during colorectal and other gastrointestinal and biliary surgeries, possibly through a mechanism of decreasing bacterial colonization of the abdominal wall edges.
The Alexis O cesarean delivery retractor is designed specifically for use during cesarean delivery to allow the passage of the neonate while still providing retraction and wound protective properties. The objective of this study was to evaluate whether the Alexis O cesarean delivery retractor reduces the rate of SSI and postoperative wound disruptions following nonemergent cesarean deliveries in an obese population. We hypothesized that the retractor would decrease the incidence of SSI and wound disruptions in this population.
Materials and Methods
This study was a prospective, randomized controlled trial at a single-center perinatal care institution, conducted from March 2013 to September 2014. The study was approved by the Saint Louis University Institutional Review Board.
Pregnant women with a predelivery BMI ≥ 30 kg/m 2 undergoing nonemergent cesarean delivery between the ages of 14 and 50 years with either singleton or twin gestations and who were capable of consent were eligible for the study. Nonemergent cesarean delivery was defined by our institution’s cesarean delivery acuity scale and included those in which there was no immediate threat to the life of the patient or fetus. Although not all cesarean deliveries in the study were elective, patients were included only if there was typical time for routine cesarean delivery preparation, the use of chlorhexidene gluconate scrub, and preoperative antibiotics.
Exclusion criteria were BMI < 30 kg/m 2 , non-English speaking, immunosuppression (eg, human immunodeficiency virus, chronic steroid use > 2 days), current concomitant infection other than chorioamnionitis (eg, pneumonia, urinary tract infection), or emergency cesarean delivery. Women were randomized to either the treatment group or to the control group in a 1:1 ratio by a computer-generated random numbers sequence.
Patients were approached for study enrollment by members of the research team during their hospital admission after the decision was made to proceed with cesarean delivery. Randomization was concealed by sequentially numbered opaque envelopes until surgery. The patient was blinded to the treatment group.
For patients assigned to the Alexis group, the retractor was placed onto the instrument table prior to patient arrival in the operating room and was not mentioned during the surgery so that the patient was blinded to her treatment group. Because of the nature of the intervention, it was not possible to blind the surgeon.
Women in the treatment group had the Alexis O cesarean delivery retractor placed after entry and extension of the peritoneal incision and clearance of adhesions. The internal ring of the retractor was placed inside the peritoneum, and the outer ring was rolled until the plastic barrier between the rings became taut. The retractor was checked to ensure that there was no inadvertent trapping of intrabdominal contents. Additional retraction was used per the surgeon’s discretion. If the patient was assigned to the control group, conventional handheld retractors were used.
All patients received 2% chlorhexidene gluconate skin preparation and received preoperative antibiotics prior to the skin incision, with cefazolin 2 g intravenously or clindamycin 900 mg plus gentamicin 1.5 mg/kg intravenously for penicillin-allergic patients, according to institution protocol. If operating times exceeded 4 hours or the estimated blood loss was greater than 2 L, an additional dose of antibiotics was administered per institutional standard protocol. The operative team was comprised of an attending and resident physician who performed the cesarean delivery and an observing medical student. No drains or wound-vacuum systems were placed. The subcutaneous layer was measured after fascial closure and was reapproximated if ≥ 2 cm in thickness.
Daily postoperative wound evaluation was performed by an attending physician who was unaware of the treatment allocation. The primary outcome was a composite of SSI and wound disruption during the 30 day postoperative period. SSI was defined and classified by Centers for Disease Control and Prevention (CDC) criteria ( Figure 1 ).
Endometritis was classified as a deep organ/space SSI and was defined as at least 2 of the following: temperature > 38°C, uterine tenderness, purulent or foul-smelling lochia, leukocytosis, or tachycardia and physician diagnosis of endometritis. Wound disruptions were defined as partial or complete opening of the incision. SSI and wound complications were assessed at 3 time points: during the initial postoperative hospital admission, at the 1–2 week follow-up visit, and 30 days postoperatively.
Patients who were diagnosed with an SSI underwent standard treatment at our institution, using broad-spectrum antibiotics. Research personnel unaware of treatment allocation collected data from all health encounters. Treatment assignment was not revealed until all data were collected. Data were collected from all health encounters available by research personnel unaware of treatment allocation. If patients did not follow up as scheduled, they were contacted via telephone and interviewed by a predetermined questionnaire to assess postoperative wound complications by the 30 day time period ( Figure 2 ).
Secondary outcomes were total surgical time; time from incision to delivery; estimated blood loss; change in hemoglobin (1–2 days preoperatively to postoperative day 1); the need for blood transfusion; antiemetic use; uterine exteriorization; the length of hospital stay; emergency room visits and hospital readmissions for wound complications; umbilical cord blood gases; and neonatal outcomes, including Apgar scores, respiratory distress, the need for intubation, sepsis, necrotizing enterocolitis, and intraventricular hemorrhage. Analysis was by intention to treat.
A sample size of 284 patients was calculated to detect a reduction in the primary outcome of SSI and wound disruptions in this patient population from 15% to 5%, assuming a power of 80% and α of 0.05. These estimates were determined based on the described rates of SSI and wound complications in similar populations, internal institutional data, and estimated reduction of infection seen with the use of barrier retractors in gastrointestinal surgeries. Assuming an approximately 5% loss to follow-up rate, a total of 300 patients was planned.
Statistical analysis was performed using a χ 2 and a Fisher exact test for categorical variables, the independent Student t test, and Kolmogorov-Smirnov test for continuous variables, as appropriate. A value of P < .05 was used to denote statistical significance. All analyses were performed using SPSS version 19.0 for Windows (SPSS Inc, Chicago, IL).
Results
During the study period, 628 patients underwent screening and 308 did not meet inclusion criteria. Nineteen women declined to participate and a total of 301 women were enrolled in this study. One hundred forty-four patients were randomized to the treatment group with the Alexis retractor and 157 women were randomized to the control group. The Alexis retractor was not used in 11 patients in the treatment group because of adhesive disease, preventing safe placement. In the control group, the Alexis retractor was used in 4 patients because of inadequate surgical field exposure at the discretion of the attending surgeon. Eleven patients were lost to follow-up during the 1–2 week postoperative period: 3 in the Alexis group and 8 in the control group. A total of 17 patients (5.6%) were lost to follow-up by the 30 day assessment: 8 in the Alexis retractor group and 9 in the control group ( Figure 3 ).
There were no differences in baseline demographic characteristics between the 2 groups, with the exception that tobacco use was more common in the control group ( Table 1 ). Median BMI was 40.1 kg/m 2 (range 30.1–75.2 kg/m 2 ) and median subcutaneous thickness was 3.0 cm (range 0.8–8.0 cm). Indication for cesarean delivery, presence of labor, ruptured membranes, chorioamnionitis, group beta streptococcus colonization, mean resident surgical experience, and type of skin and uterine incision were similar between the 2 groups ( Table 2 ).
| Characteristics | Alexis retractor (n = 144) | Control (n = 157) | P value |
|---|---|---|---|
| Maternal age, y | 28.5 (24.0–33.0) | 29.0 (24.5–32.0) | .77 |
| Gestational age, wks | 38.9 (37.0–39.3) | 39.0 (37.0–39.4) | .80 |
| Race | |||
| Caucasian | 44 (30.6%) | 50 (31.8%) | .88 |
| African-American | 95 (66.0%) | 103 (65.6%) | .88 |
| Other | 5 (3.5%) | 4 (2.5%) | .88 |
| Gravidity | 3 (2–4) | 3 (2–4) | .99 |
| Parity | 1 (1–2) | 1 (0–2) | 1.00 |
| Body mass index, kg/m 2 | 39.9 (35.6–45.6) | 40.6 (34.9–46.5) | .60 |
| Twin gestation | 11 (7.6%) | 13 (8.3%) | 1.00 |
| Tobacco use | 27 (18.8%) | 46 (29.3%) | < .05 |
| Preexisting diabetes | 22 (15.3%) | 17 (10.8%) | .33 |
| Gestational diabetes | 24 (16.7%) | 19 (12.1%) | .33 |
| Chronic hypertension | 28 (19.4%) | 33 (21.0%) | .85 |
| Hypertensive disorders of pregnancy | 40 (27.8%) | 34 (21.7%) | .27 |
| Asthma | 16 (11.1%) | 25 (15.9%) | .30 |
| Number of prior cesarean deliveries | 1 (0-1) | 1 (0-2) | .86 |
| Number of prior abdominal surgeries | 1 (0-2) | 1 (0-2) | .90 |
| Characteristics | Alexis retractor (n = 144) | Control (n = 157) | P value |
|---|---|---|---|
| Indication for cesarean delivery | |||
| Repeat cesarean delivery | 79 (54.9%) | 85 (54.1%) | .49 |
| Nonreassuring fetal status | 27 (18.8%) | 25 (15.9%) | .49 |
| Arrest disorders (dilation or descent) | 15 (10.4%) | 20 (12.7%) | .49 |
| Malpresentation | 20 (13.9%) | 20 (12.7%) | .49 |
| Other | 3 (2.1%) | 7 (4.4%) | .49 |
| Median resident surgical experience, y | 2.5 (2.0–3.0) | 2.5 (2.0–3.0) | .92 |
| Labor | 61 (42.4%) | 57 (36.3%) | .34 |
| Ruptured membranes | 44 (30.6%) | 42 (26.8%) | .55 |
| Time from rupture of membranes to delivery, h | 7.5 (4.4–17.0) | 12.8 (5.7–24.0) | .16 |
| Chorioamnionitis | 8 (5.6%) | 6 (3.8%) | .66 |
| Group beta streptococcus colonization | 38 (31.4%) | 49 (36.0%) | .52 |
| Skin incision | |||
| Low transverse | 130 (90.3%) | 144 (91.7%) | .50 |
| Supraumbilical transverse | 8 (5.6%) | 10 (6.4%) | .50 |
| Vertical | 6 (4.2%) | 3 (1.9%) | .50 |
| Uterine incision | |||
| Low transverse | 135 (93.8%) | 144 (91.7%) | .42 |
| High transverse | 4 (2.8%) | 10 (6.4%) | .42 |
| Classical or T incision | 5 (3.5%) | 3 (1.9%) | .42 |
| Subcutaneous thickness, cm | 3.0 (2.0–4.0) | 3.0 (2.3–4.0) | .66 |
| Subcutaneous layer closure | 128 (88.9%) | 135 (86.0%) | .56 |
| Skin closure | |||
| Staples | 40 (27.8%) | 41 (26.1%) | .85 |
| Subcuticular sutures | 104 (72.2%) | 116 (73.9%) | .85 |
Fifty-four patients (19.0%) experienced the primary outcome of SSI or wound disruptions within the 30 day postoperative period. Thirty-nine patients had an SSI and 36 had a wound disruption because the 2 are not mutually exclusive. Of the SSI that occurred during the 30 day postoperative period, 27 were superficial incisional infections and 12 were deep organ/space infections. All of the deep organ/space infections occurred during the initial postoperative hospitalization, whereas only 4 of the superficial incisional infections and no wound disruptions occurred in the immediate postoperative period.
There were no differences in the primary outcome of SSI and wound disruptions between the Alexis retractor and the control group during the 30 day postoperative period (20.6% vs 17.6%, P = .62, Table 3 ). There were also no differences in SSI or wound disruptions during the time periods of initial hospitalization and the 1–2 week follow-up assessment. Patients in the Alexis retractor group had a lower rate of uterine exteriorization (55.6% vs 88.5%, P < .001).
| Variables | Alexis retractor (n = 144) | Control (n = 157) | P value |
|---|---|---|---|
| Any SSI or wound disruption during initial postoperative hospital admission | 8 (5.6%) | 8 (5.1%) | 1.00 |
| Surgical site infection | 8 (5.6%) | 8 (5.1%) | 1.00 |
| Superficial incisional | 2 (1.4%) | 2 (1.3%) | 1.00 |
| Deep organ/space | 6 (4.2%) | 6 (3.8%) | 1.00 |
| Wound disruption | 0 (0.0%) | 0 (0.0%) | — |
| Alexis retractor (n = 141) | Control (n = 149) | P value | |
|---|---|---|---|
| Any SSI or wound disruption during 1–2 week follow-up visit | 25 (17.7%) | 22 (14.8%) | .60 |
| Surgical site infection | 19 (13.5%) | 16 (10.9%) | .62 |
| Superficial incisional | 13 (9.2%) | 10 (10.7%) | .99 |
| Deep organ/space | 6 (4.2%) | 6 (4.0%) | .99 |
| Wound disruption | 15 (10.6%) | 15 (10.1%) | 1.00 |
| Alexis retractor (n = 136) | Control (n = 148) | P value | |
|---|---|---|---|
| Any SSI or wound disruption during 30 d postoperative period | 28 (20.6%) | 26 (17.6%) | .62 |
| Surgical site infection | 20 (14.7%) | 19 (12.8%) | .78 |
| Superficial incisional | 14 (10.3%) | 13 (8.8%) | 1.00 |
| Deep organ/space | 6 (4.3%) | 6 (4.1%) | 1.00 |
| Wound disruption | 18 (13.2%) | 18 (12.2%) | .93 |
There were no differences in other outcomes assessed, including total surgical time, time from skin incision to delivery, antiemetics given intra- or postoperatively, estimated blood loss, change in hemoglobin, need for blood transfusion, length of hospital stay, emergency room visits, or readmission to the hospital for wound infections ( Table 4 ). There were no differences in Apgar scores, umbilical cord gases, or other neonatal outcomes studied ( Table 5 ). There were no adverse effects observed in either group.
| Variable | Alexis retractor (n = 144) | Control (n = 157) | P value |
|---|---|---|---|
| Uterine exteriorization | 80 (55.6%) | 139 (88.5%) | < .001 |
| Total surgical time, min | 64.5 (53.3–75.0) | 66.0 (55.0–77.5) | .74 |
| Time from skin incision to delivery, min | 13 (9.1–17.0) | 12 (8.8–17.0) | .79 |
| Estimated blood loss, mL | 700 (600–900) | 700 (500–900) | .51 |
| Change in hemoglobin, g/dL | –1.7 (–2.3, –1.1) | –1.5 (–2.1, –1.0) | .33 |
| Need for blood transfusion | 7 (4.9%) | 9 (5.7%) | .94 |
| Antiemetics given intraoperatively | 35 (24.3%) | 47 (29.9%) | .33 |
| Antiemetics given postoperatively | 33 (22.9%) | 32 (20.4%) | .69 |
| Length of hospital stay, d | 3 (3–4) | 3 (3–4) | .98 |
| Emergency room visit for wound complication | 8 (5.9%) | 11 (7.4%) | .79 |
| Hospital readmission for wound complication | 4 (3.0%) | 1 (0.7%) | .20 |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
