The described technique of umbilical ligament flap to prevent pelviperineal complications after APR was successfully applied in seven patients in the present series. There was no attributable morbidity to the partial bladder mobilisation and fixation of umbilical ligaments to the sacrum. No urinary morbidity or functional deterioration was recorded. Per-se for the bladder, mobilisation happens only anteriorly at the dome and not laterally. Hence no angle change happens in the vesicoureteric junction, and no neurovascular or mechanical compromise was expected or encountered.
The colorectal surgical community agree about the need to fill the pelvic free space and always attempts it after APR. The aim is to decrease small bowel descent, SBO and perineal wound complications.
In the case of commonly practised omental placement, the technical challenge can be reaching into the rectal space. However, omentum can be lengthened by partially dividing the infra-colic portion, which is seldom desired. Also, a free-placed omentum can move out of the pelvis based on the patient's position. Recent studies also show that it does not reduce the rates of small bowel obstruction and perineal complications.[13], [18].
When compared to autologous tissue methods of pelvic closure, namely omentum, myocutaneous flaps, and pelvic peritoneum, the use of mobilised umbilical ligament is particularly attractive as it takes the least amount of time, the tissue being available in the pelvis itself and is technically the simplest to perform even with minimally invasive approaches.
With regards to the prosthetics methods of preventing small bowel obstruction, the umbilical flap offers a much cheaper solution to the unrelenting problem of small bowel descent while circumventing the issues surrounding foreign bodies, infections, and the need for repeat operations[8].
Reason for decreased perineal wound infection
The abdomen is designed to exert maximum pressure into the pelvis to aid defecation and childbirth. Two forces act on the perineum, which causes tension at the wound site.
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Weight of the intraabdominal viscera
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External pressure by the diaphragm and abdominal wall muscles - Pascal’s law states that external pressure applied onto a confined space is distributed or transmitted evenly to the walls in all directions (Pressure = \(\raisebox{1ex}{$Force$}\!\left/ \!\raisebox{-1ex}{$Area$}\right.\)) [19], [20]
First, by successfully holding up the small bowel, the flap doesn’t allow the weight of the intraabdominal viscera to act on the perineal wound.
Secondly, with the Pascal law, the pressure generated in the abdomen by an external force like the diaphragm or abdominal wall muscles will get transmitted to the perineal wound as there is free fluid and gas flow between the space above and below the flap. The increased abdominal pressure will increase the pressure in the fluid /gas in the pelvis, which is transmitted to the perineum. Herein comes the role of a surgical drain. Any increase in pressure is neutralised by a working drain and hence not allowing the pressure to be transmitted to the perineum.
Hence would it be advantageous to have a drain when there is no flap? Not that efficient because when the flap separates the abdomen and the pelvis, the transmitted force is through the gas and fluid and not borne by intra-abdominal viscera. In the absence of a flap, the intra-abdominal viscera enter the pelvis, causing a significant fraction of pressure to be transmitted through them. They also cause drain blocks to compromise the functionality of the same.
This possibly is the reason why filling the space with tissues like the omentum and prosthesis never really solved the problem.
Hence the objective is to create an air/fluid-filled pelvic space separate from the abdomen and to decompress it with a surgical drain (Fig. 4).
Another independent advantage is that per the present standard guidelines, clinico-radiologically stage I rectal cancer is treated by upfront surgery.20–25% of clinico-radiologically stage I rectal cancer can get upstaged after upfront proctectomy. Those cohorts of patients would require adjuvant radiation, and this proposed technique can consistently keep the small bowel away to evade radiation toxicity[21]–[23].
Moreover, as per current standard guidelines, clinico-radiologically stage I rectal cancer is treated by upfront surgery.20–25% of clinico-radiologically stage I rectal cancer could get upstaged after upfront proctectomy. Those cohorts of patients would require adjuvant radiation, and this proposed technique can consistently keep the small bowel away from the field of radiation to avoid radiation toxicity[21]–[23].
Thus, while the procedure is straightforward and technically sound, its efficacy needs a more robust evaluation. The present series is a pilot study, and we require a much larger sample size with a comparator arm in the future. Hence, what can be inferred from our study is a novel ‘idea’ for the prevention of pelviperineal complications that needs to be further ‘developed’ and ‘explored’.
The only significant limitation of the technique is that it cannot be applied in female patients with an intact uterus and in other patients following a total pelvic exenteration. However, as an extension to the use of the urinary bladder, the uterus can be retroverted in female patients after APR and hitched to the sacrum. The authors have found that this is effective, but however, the problem of small bowel descent is less pronounced in female patients with an intact uterus. This is because the intact uterus many times holds the intraabdominal viscera above the pelvis, maintaining the fluid/air-filled area below it.
The present series is intended to introduce a simple, low-cost, safe, and potentially effective technique for preventing small bowel descent, small bowel obstruction (SBO) and perineal complications. The major shortcomings of this study are small numbers and a need for a comparative arm.