Better operative outcomes achieved with the prone jackknife vs. lithotomy position during abdominoperineal resection in patients with low rectal cancer

APR is a complex and challenging surgical procedure. The present study compared the clinical, pathological, and oncological outcomes of PJ-APR vs. LT-APR in low rectal cancer patients in order to confirm which position will provide more benefits to patients undergoing APR. The present study showed that the PJ position was superior to the LT position in terms of operative outcomes. Indeed, compared with LT-APR, the duration of anesthesia and surgery was shorter by >50 min, estimated blood loss in PJ-APR was reduced by >100 mL, and fewer patients needed blood transfusions with PJ-APR. Furthermore, postoperative hospitalization was significantly shorter with PJ-APR, and some of the postoperative complications were significantly reduced with PJ-APR. There was no difference in oncological outcomes between PJ-APR and LT-APR including overall survival, disease-free survival, local recurrence, and distant metastases. These results are supported by previous studies [14].

Perineal dissection is complicated in APR, and performing APR in the PJ position improved visualization, reduced the risks related to the operation, and made the operation easier to perform during this difficult part. Although the LT position provides adequate access to the rectovaginal septum and allows easy access to the posterior face of the rectum [10], this position is uncomfortable for the surgeons and assistants, blood tends to accumulate in the operation area, and adequate lighting is often challenging. Therefore, the surgeon has to spend more time for exposure, operative vision, and hemostasis and also to avoid iatrogenic damage to nerves, blood vessels, and organs. Especially, the anterior wall of the rectum is more difficult to access. Although the patient position needs to be changed during the operation in PJ-APR, this does not need a lot of time [14]. The PJ position is appropriate for almost all proctological surgeries, it allows an excellent exposure of the posterior and anal perineum and the anterior face of the rectum, provides a more comfortable position for the surgeon and assistants, results in less blood accumulation, and enables better lighting [10]. Our results showed that the time needed to change the operation position during PJ-APR was less than 18 min (data not shown); more time was saved in the process of perineal dissection. Moreover, data also showed that the estimated blood loss in PJ-APR was reduced by more than 120 mL compared with LT-APR and that the rate of patients needing blood transfusion was 6% during PJ-APR compared with 14% during LT-APR. In addition, postoperative hospitalization was significantly shorter after PJ-APR compared with LT-APR, which may indicate that patients recovered faster after PJ-APR than LT-APR.

APR requires a complex positioning and exposes the patients to the risks of a major surgery, as well as to the risks specific to this procedure [19]. Previous studies have shown that the incidence of intraoperative perforations was markedly reduced with PJ-APR compared with supine APR [12] and that intraoperative bowel perforation in extralevator APR was significantly reduced when the perineal dissection was performed in the PJ position rather than in the LT or Lloyd-Davies position [11]. The most common immediate complication is intra-abdominal or pelvic abscesses, which has been reported to account for 32% of postoperative complications [20]. The incidence of pelvic abscesses has been estimated at 3% among patients who underwent APR, and it is generally recognized that a pelvic abscess requires reoperation or readmission more frequently than perineal wound infection [21]. Other studies have shown that the risk of postoperative sexual or urinary dysfunction ranges from 10% to 60% [14,22].

In the present study, the incidence of perineal wound infection and incision dehiscence was 1.4% in the PJ-APR group compared with 8%–16% in the LT-APR group. The incidence of pelvic abscesses was also lower with PJ-APR (1.4%) than with LT-APR (2.7%). These results are supported by a previous study (11% vs. 36%) [13], but a much lower incidence was observed in the present study. This low postoperative complication rate may be explained, at least in part, by the fact that all patients underwent curative APR, and not palliative surgery. The other reason is that patients with comorbidities were excluded. In addition, our patients did not receive any neoadjuvant therapy, which could partially explain the low rate of infection. Previous studies have reported infection rates as high as 50% and substantial morbidity, especially after neoadjuvant radiation and chemoradiation therapy [23,24].

Reported survival and local recurrence rates after APR for rectal cancer vary widely. APR is generally associated with poor oncological outcomes [4,25,26]. Indeed, the 5-year cancer-specific survival after sphincter-sparing resection was 74% compared with 62% after APR [27]. However, the same group showed that 2 years after surgery, local recurrence rates were similar with both procedures [28].

A large database analysis suggested that there has been no improvement in mortality following APR from 1996 to 2004 [1]. In the present study, the perineal phase of APR was carried out in the PJ position, followed by abdominal surgery. Because the inferior mesenteric artery is not ligated during the same procedure phase, we were concerned that this may potentially facilitate arterial transport of cancer cells, resulting in metastasis and poor prognosis. However, results showed that overall survival, 5-year overall survival, and oncological outcomes were comparable between the two groups. Cox regression analysis excluded the operative position as being an independent prognostic factor, while gender and pathologic N stage were independent factors associated with survival. Notably, there were no significant differences in pathologic T or N stages, or in the degree of differentiation. However, the number of patients with pT3 and/or poorly differentiated tumors was slightly higher in the PJ-APR group.

The present study suffers from some limitations. First, we were unable to account for the CRM, which has previously been associated with increased local recurrence and reduced patient survival [29-31]. Second, we included all histological subtypes of rectal cancer. However, adenocarcinoma largely predominates (98.3%), and we do not think that the few cases of other subtypes could impact the results much. Third, because of the retrospective nature of the study, we are unable to obtain reliable data about the extralevator approach. Finally, each surgeon selected the operative position for each specific patient based on its appreciation of a number of factors, but there were no specific criteria for LT or PJ. In addition, for a specific patient, a surgeon may have selected the LT position, while another surgeon would have selected the PJ position. Therefore, we cannot provide any exact criteria. We agree that it could have introduced a bias, but results showed that the patients were comparable for most characteristics at baseline.