Clinical profile.
This study enrolled 81 participants that underwent surgery for sigmoid volvulus, majority of whom were males 63(77.8%) with a mean age of 55.1(SD=14.2) years. This is because sigmoid volvulus is known to be common among males in the older age groups (40-50) years in third world countries (16). Majority were from rural areas 58(71.6%) probably due to the catchment area of the hospitals being rural settings.
We noted that 27(33.3%) of the study participants had both a low systolic blood pressure and a high pulse rate and therefore classified as hemodynamically unstable. This percentage was higher than that reported in Turkey where hemodynamic instability was seen among 102 (24.3%) of the patients presenting with sigmoid volvulus (17). The difference could be because in this study a big number of patients had bowel gangrene or sigmoid perforation which both worsen the condition of the patient resulting in hypotension and tachycardia which constituted hemodynamic instability in this study.
Non-viable gut was found in 27(33.3%) of the participants while 15 (18.5%) of the patients had a bowel perforation. Percentage of non-viable gut in this study was higher than that reported by Mulugeta & Awlachew (18) in Ethiopia where 26% had non-viable bowel but was lower than the percentage reported by Selçuk Atamanalp (17) in Turkey (63.1%) and Emna (19) in Tunisia (40%). The high percentage of non-viable bowel seen in our study is mainly because of delayed presentation where 46.9% of the study participants presented after 3 days of symptoms. Delay was probably due to inaccessibility of hospital from the rural areas.
Majority of the patients had a colostomy placed 61(75.3%) either due to the condition of the gut or the hemodynamic status. This percentage was comparable to the one reported by Lee (20) in Korea (74.3%) but higher than that reported by Chalya & Mabula (14) in Tanzania and Okello (21) in Uganda at Mulago national referral hospital. The studies in Tanzania and Mulago had both emergency procedures and some elective procedure in which the volvulus was de-rotated endoscopically and then surgery done later. All the patients operated in our study underwent an emergency laparotomy and this could explain the difference in percentage of patients that had a stoma placed since emergency surgery increases possibility of stoma placement (22). The other explanations for having a big number of patients undergoing stoma placement could be because of the significant number of patients with bowel gangrene, hemodynamic instability and perforation with gross contamination which conditions increase the risk for anastomotic leakage making stoma placement the safer option.
Early outcomes.
In this study, 10 of the patients died representing a mortality of 12.3%. Our findings were in agreement with findings of a systematic review by Selvaraj & Palaniswamy (23) who reported that mortality following sigmoid volvulus ranged from 10-50%. Also the mortality found in this study was comparable though slightly lower than that reported in Mulago (15.9%) (21) and Tanzania (17%) (14).
The mortality we found was higher than that reported by Awedew (24) in Ethiopia (6.45%), Jumbi & Kuremu (25) in Kenya (3.3%) and Wismayer (10) in northern Uganda (7.7%). The differences seen in mortality could be because these studies that reported lower mortality had some patients operated electively after derotation yet in our study there were no facilities for endoscopic derotation, yet emergency procedures are associated with a higher mortality (15). Also the high percentage of patients with perforated sigmoid (18.5%) could have contributed to the high mortality.
Thirty seven (45.7%) of the participants had at least one complication with the commonest complication being surgical site infection seen in 21(25.9%) of the study participants. The percentage of patients with complications was comparable to that reported by Lee (20) where 40.0% of the patients that had emergency surgery for sigmoid volvulus got complications. Also our findings were in agreement with studies by Emna (19) in Tunisia, Mulugeta & Awlachew (18) in Ethiopia, Chalya & Mabula (14) in Tanzania and Wismayer (10) in northern Uganda who reported surgical site infection as the commonest complication. This is possibly because these surgeries would be classified as contaminated or even dirty if there is perforation which classifications are associated with a high risk of surgical site infection.
The percentage of complications reported in our study was higher than that reported by Jumbi & Kuremu (25) in Kenya (21.7%), Chalya & Mabula (14) in Tanzania (20.5%) and Wismayer (10) in northern Uganda (17.5%). The high percentage of complications in this study could be attribute to the fact that a high percentage of the patients had perforated sigmoid (18.5%) which resulted in peritonitis. Given that surgical site infection was the commonest complication, the peritonitis could partly explain the high percentage of complications. The occurrence of sigmoid perforation can again be attributed to late presentation seen among most of the patients in our study since the median duration of symptoms at presentation was 3 days.
The median length of hospital stay was 8(IQR=7-11) days with 40(49.4) of the patients staying in hospital for a duration above the median (>8 days). This LOS was comparable to that reported by Awedew (24) in Ethiopia (median=8 days) but slightly lower than that reported by Lee (20) in Korea (Median =11 days), Jumbi & Kuremu (25) in Kenya (average 11.8 days) and Chalya & Mabula (14) in Tanzania (Median=14 days). The High length of hospital stay could be attributed to the high occurrence of complications which are known to increase length of hospital stay.
Factors associated with early adverse outcomes.
The variables that were independently and significantly associated with mortality were hyperkalemia and presence of a sigmoid perforation. Our findings were in agreement with what was reported by Lee (20) in Korea who noted that mortality was significantly associated with presence of sigmoid colon gangrene or perforation (P=0.001), Chalya & Mabula (14) in Tanzania who reported that bowel gangrene or perforation predicted adverse outcomes and Wismayer (10) in northern Uganda who reported that electrolyte imbalances were associated with unfavourable outcomes. Presence of hyperkalemia may be an indicator of acute kidney injury which has a potential to increase mortality while sigmoid perforation results in generalized peritonitis which significantly increases mortality.
The variables that were independently and significantly associated with occurrence of complications were a history of hypertension and presence of hemodynamic instability. Our findings are in agreement with what was reported by Lee (20) in Korea who noted that patients who had a concomitant disease like hypertension (P=0.001) and those who had hemodynamic instability or shock (P=0.001) had an increased risk of getting complications (20). Also in agreement are the findings by Okello (21) at mulago who reported that patients who had comorbid diseases like, hypertension had increased risk (21). Hemodynamic instability increases the risk of complications since it impairs healing and hence increasing risk of wound complications and even anastomotic leakage. Presence of hypertension more so if poorly controlled impairs perfusion of the tissues due to the associated arteriosclerosis impairing the healing of tissues and hence the occurrence of wound complications.
The variables that were independently and significantly associated with prolonged hospital stay were duration of symptoms greater than 3 days and having hemodynamic instability. Though many studies have reported about length of stay among patients undergoing sigmoid volvulus surgery, this is the first study that has reported on the factors associated with length of stay following surgery for sigmoid volvulus to best of our knowledge. Delayed presentation increases the risk of bowel ischemia, gangrene and perforation. These in turn increase the risk of post-operative complications as was reported by Chalya & Mabula (14), which complications eventually results in prolonged hospital stay. The presence of hemodynamic instability also results in complications which in turn increase the length of hospital stay.
Strength and limitations of the study
This was a multicentre prospective cohort study that increases the generalizability of the findings.
However, our findings are limited by the fact that the centres did not have endoscopic services which can be used to de-rotate volvulus and do the surgeries electively; which procedure has been associated with a better outcome. Therefore our finding may not be generalizable to the centres where endoscopic derotation is practiced.