Pfannenstiel Extraction Site Reduces Postoperative Extraction Site Hernias after Robotic Radical Prostatectomy

Introduction

Over the past two decades, robotic-assisted radical prostatectomy (RARP) has become the preferred surgical approach for prostate cancer, replacing open prostatectomy because of comparatively reduced blood loss, shorter hospital stays, and improved postoperative outcomes. ¹ However, despite these advantages, RARP is not without complications. One such concern is the development of postoperative hernias at a higher rate than traditional open radical prostatectomy. ^2,3 Following RARP, hernias can develop at the port incisions, extraction site, and within the inguinal region. Incisional hernia (IH) rates vary, with larger prostate size correlating with higher risk. ⁴ Other risk factors for IH after RARP include older age, concomitant pelvic lymph node dissection, higher body mass index (BMI), smoking history, previous abdominal operation, and wound infection. ^2,3,5,6

Attempts have been made to identify the optimal approach to extract specimens in RARP to reduce the risk of postoperative extraction site hernias. Groups have compared extraction through the lateral port site as opposed to the midline camera port incision with no significant difference in hernia rates. ⁷ Adjusting the midline incision to a transverse configuration has been shown to decrease but not eliminate the risk of an extraction site hernia. ⁸ As postoperative IH can lead to bowel incarceration or strangulation requiring emergent repair, identifying an extraction method to prevent these hernias is an important consideration for surgeons.

Pfannenstiel incisions have demonstrated efficacy in reducing the risk of IH. In colorectal operation and hepato-pancreato-biliary operation, Pfannenstiel incisions have been associated with decreased extraction site hernia rates. ^9,10 There are limited data in the urologic literature on the use of Pfannenstiel extraction in RARP, with only a small single-surgeon study published. ¹¹

Our study aimed to assess postoperative hernia rates after RARP by extraction method as well as risk factors for postoperative hernias in a prospectively maintained database. We secondarily assessed the incidence of clinically relevant postoperative hernias by extraction method.

Patients and Methods

This study was exempt from institutional review board approval given its retrospective nature. A prospectively maintained database was queried for all patients undergoing RARP from November 2006 to June 2023. Patients with a conversion to an open procedure were excluded from analysis. We collected demographic features, oncologic and pathologic features, surgical data including approach and extraction site, 30-day postoperative complications, and postoperative hernia rates. Specimen extractions were performed via extending the periumbilical port incision or a separate Pfannenstiel incision per surgeon preference (Fig. 1). Assistant ports had fascial closures per surgeon preference. Major complications were defined as any grade 3 complication or higher according to the Clavien–Dindo classification. For hernias identified within the cohort, they were categorized by the presence of symptoms, physical exam findings, and/or imaging findings. Clinically relevant hernias were defined as hernias discovered based on symptoms or exam findings rather than identification on imaging alone. Chi-square and Student’s t-test analyses were done to compare patients by extraction site type for categorical and continuous variables, respectively. Univariable and multivariable logistic regressions were used to identify risk factors for postoperative extraction site hernias by extraction site used.

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FIG. 1.

Representative images of incision configuration in patients within our cohort. (A) Pfannenstiel extraction and (B) Midline extraction.

Results

A total of 1465 patients met inclusion criteria. Table 1 shows cohort demographics and operative details. In total, 347 patients (23.7%) had specimen extraction via Pfannenstiel incision, whereas 1118 patients (76.3%) were via the midline periumbilical port. The Pfannenstiel cohort had more non-white patients (40.3%) compared with the periumbilical cohort (27.8%). The operative time in the Pfannenstiel cohort was longer than the periumbilical cohort (272 vs 229 minutes, p < 0.01). There was no difference in prior abdominal operations, prostate size, BMI, or 30-day major complications.

Table 2 shows rates of hernia development after RARP by extraction incision used. The overall hernia rate was significantly lower in the Pfannenstiel cohort (13.0% vs 19.1% for the periumbilical group, p < 0.01). Two patients (0.6%) with a Pfannenstiel incision developed extraction site hernias compared with 83 (7.4%) with a periumbilical extraction. The rate of clinically significant hernias was also lower in the Pfannenstiel group at 10.09% (vs 14.49% in the periumbilical group, p = 0.04). Although 7.0% of the periumbilical group developed clinically relevant extraction site hernias, there were no such hernias in the Pfannenstiel group (p < 0.01).

Multivariable logistic regression for clinically relevant extraction site hernias can be seen in Table 3. Hispanic race was associated with reduced odds of such hernias (odds ratio [OR] 0.10, p = 0.02), as was the use of a Pfannenstiel extraction (OR 0.08, p < 0.01). Age, other racial identities, endoscopic band ligation, BMI, prostate size, and operative time did not have a statistically significant impact on the odds of postoperative clinically significant extraction site hernia development.

Figure 2 shows Kaplan–Meier curves assessing hernia-free survival for all patients by type of extraction used. On evaluation of overall hernia-free survival, the rates are similar between the two groups (Fig. 2A). The Pfannenstiel cohort had significantly improved extraction site hernia-free survival and clinically relevant extraction site hernia-free survival (Fig. 2B, C).

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FIG. 2.

Kaplan–Meier curves for hernia-free survival by extraction type. (A) Overall hernia-free survival. (B) Extraction site hernia-free survival. (C) Clinically relevant extraction site hernia-free survival.

Discussion

In this study, we analyzed postoperative hernia rates in patients undergoing RARP. We found that patients who had specimen extraction via a Pfannenstiel approach had significantly fewer postoperative extraction site hernias than those using a midline periumbilical incision. On multivariable analysis, Pfannenstiel extraction was associated with significantly reduced odds of clinically relevant extraction site hernias compared with midline periumbilical extraction. We focused on clinically relevant hernias to maximize the deliverability and relevance of our endpoints. Furthermore, this is the largest cohort to our knowledge to explore the feasibility and safety of a Pfannenstiel extraction for a very commonly performed robotic urologic operation. Of note, there was an increased operative time for patients who had a Pfannenstiel extraction; these cases were mainly done by a single surgeon who performs a Retzius-sparing technique, which likely accounts for this difference.

Although RARP has significant benefits over open prostatectomy, it is associated with an increased risk of postoperative hernias with IH rates as high as 9.7%. ^2,4,6 Preventing postoperative IHs is paramount, as these can lead to sequelae such as obstruction or pain that require readmission and reoperation with failure rates reported as high as 45%. ¹² Importantly, the risk of post-RARP hernias is increased in patients who are older, have a smoking history, have a higher BMI or other comorbidities, and have a history of prior abdominal operation. ^3,5

Prior series have investigated other operative modifications to prevent IH after RARP. Beck and colleagues explored the use of a transverse camera port incision in a cohort of 900 patients who underwent RARP. IHs were more common with the traditional vertical midline camera port incision compared with the transverse approach (5.3% vs 0.6%). On multivariate analysis, they found that increased BMI, increased prostate weight, older age, and decreased International Index of Erectile Function-5 (IIEF-5) score were associated with an increased hernia risk. ⁸ Seveso and associates examined the impact of modifying the extraction incision site on hernias after RARP. In their cohort of 800 patients, they found that the rate of extraction site hernias was slightly lower if an off-midline incision was used for extraction (4.5% compared with 5% for a supraumbilical midline incision). ⁷ Similar to other groups, they found that larger prostate size was associated with increased rates of postoperative hernia development. ⁷ Notably, IH repair rates were 50% for midline extractions versus 28% for extraction off the midline, although the reason for this difference in their cohort is unclear. Other groups have evaluated how the incision is closed, although one review noted that the data are mixed on running versus interrupted suturing and the impact of suture type used on hernia rates. ¹² Soputro and colleagues explored the use of single-port robotics to reduce postoperative hernia development. In their cohort of 1103 patients with extraperitoneal, transperitoneal, and transvesical approaches used, they identified only two cases of IH (both after the transperitoneal approach). ¹³ Although this approach is not necessarily available to every surgeon, their results suggest a potential benefit of the single-port robotic platform for radical prostatectomy.

Other groups have previously evaluated the use of a Pfannenstiel incision to prevent IHs after prostatectomy. Lunacek et al. used the Pfannenstiel incision in 163 open radical prostatectomies, noting no IHs in their cohort and overall good cosmesis and exposure using the approach; notably, this was a single-center prospective analysis without a comparison arm. ¹⁴ Manohoran and associates used a modified Pfannenstiel approach for open prostatectomy in 544 patients and found only one recurrent inguinal hernia with no reported IHs in their cohort. ¹⁵ Zukiwskyj and colleagues reviewed 69 RARP cases in a single-surgeon cohort and found a lower rate of IHs after switching from supraumbilical port site extraction (12.5%) to a Pfannenstiel incision extraction. No hernias were reported for Pfannenstiel cases, and a reduction in supraumbilical port site hernias was seen (6.7%). ¹¹ Our study reinforces this finding based on a larger cohort of 1464 patients. Although our reported hernia rates in our Pfannenstiel subgroup were higher at 0.6%, this is likely attributable to the larger cohort size.

Our study is not without limitations. First, this is a single-institution series from a tertiary care center queried in a retrospective fashion. Follow-up for hernias may be constrained if patients sought care outside our system after their index procedure and if their records were not available within our electronic medical records. Second, the choice of extraction site was based on surgeon preference, and most of the Pfannenstiel extractions were performed under the supervision of a single surgeon. We also lack granular data in our dataset to clarify the association with reduced extraction site hernias and Hispanic race; separate analysis did not show a statistically significant difference between Caucasian and Hispanic patients with respect to BMI to account for this difference (unpublished data); further work is needed to clarify this association. We also did not capture patient-reported outcomes such as postoperative pain scores or cosmesis perception for the additional Pfannenstiel incision; these are important metrics to consider when using a separate incision for extraction. Future prospective studies assessing Pfannenstiel incisions for reduction of IH after RARP should incorporate these critical metrics.

Conclusions

Our study found that using a separate Pfannenstiel extraction site for specimen extraction in RARP can decrease the risk of postoperative hernias. This approach should be considered by surgeons performing RARPs to minimize postoperative morbidity.