Postoperative pneumoperitoneum as detected by CT: prevalence, duration, and relevant factors affecting its possible significance

Postoperative Pneumoperitoneum in Pediatric Patients: Residual Air or Surgical Complication? A Prospective Study

Background: Residual postoperative pneumoperitoneum (RPP) can be confused with postoperative complications. Our aim was to study RPP characteristics in pediatric patients. Materials and Methods: Prospective study in children with noncomplicated appendicitis, from July to December 2019, divided into open appendectomy (OA) or laparoscopic appendectomy (LA). Abdominal ultrasounds were performed daily to assess RPP. Demographic, surgical data, and RPP characteristics were analyzed. Results: Forty-one patients (63% male) aged 9.8 ± 2.9 years were included: 19 had OA and 22 LA. RPP was present in 90.9% of LA patients versus 21.1% of OA (P < .001). RPP disappeared by the postoperative day (POD) 2, in all OA patients. RPP was present in 90.9% of LA patients in POD 1, 53.8% on POD 2, 25% on POD 3, and in no patient from POD 4. RPP prevalence was not associated with surgical duration, age, gender, or type of appendicitis. RPP was associated with pain radiating to the shoulders (PRS) (P = .018), with a sensitivity of 50.0% and specificity of 88.23% for diagnosis. Conclusions: Surgical approach was the main factor associated with RPP persistence. PRS in the physical examination may be helpful for diagnosis when RPP is suspected. The persistence of RPP beyond POD 4 is uncommon, and should be considered when making decisions.

The characteristics of residual pneumoperitoneum after laparoscopic colorectal surgery

INTRODUCTION

Despite the popularity of laparoscopic surgery, it remains unclear whether residual pneumoperitoneum influences the patient's postoperative course. This study aimed to evaluate the characteristics of residual pneumoperitoneum.

METHODS

This retrospective study included 201 Japanese patients who had undergone elective laparoscopic colorectal surgery. The patients were divided into groups, with and without anastomotic failure; the non-anastomotic failure group was further divided into subgroups, with and without residual pneumoperitoneum. Patient characteristics were compared between the various groups.

RESULTS

The group with residual pneumoperitoneum included 57 patients (30.3%). Percutaneous drainage was required for one patient with residual pneumoperitoneum. Univariate analyses revealed that residual pneumoperitoneum was associated with low values for body mass index (BMI) and subcutaneous fat area (SFA). Furthermore, relative to the group with anastomotic failure, the group without anastomotic failure but with residual pneumoperitoneum had lower values for inflammatory markers.

CONCLUSION

Low BMI and SFA values were identified as risk factors for residual pneumoperitoneum. Inflammatory markers may be useful as indicators for avoiding emergent surgery when it is difficult to differentiate between asymptomatic residual pneumoperitoneum and free air related to anastomotic failure.

The risk of shoulder pain after laparoscopic surgery for infertility is higher in thin patients

Postlaparoscopic shoulder pain (PLSP) is a common clinical problem that needs to be addressed by medical professionals who are currently perform laparoscopic surgeries. The purpose of this study was to determine the perioperative clinical factors and demographic characteristics associated with PLSP. A prospective observational study was performed with 442 inpatients undergoing laparoscopic surgery for infertility. The pain visual analogue scale was used as the measuring instrument. To identify the predictors of PLSP, we performed multivariate conditional logistic regression. PLSP was correlated with body mass index (BMI, odds ratio = 0.815). The incidence of shoulder pain and more severe shoulder pain in patients with a lower BMI was significantly higher than it was in patients with a higher BMI, and BMI was significantly negatively correlated with PLSP. Most of the patients (95%) began to experience shoulder pain on the first postoperative day, and it rarely occurred on the day of surgery. Patients with lower BMI presented a higher risk of reporting shoulder pain on the first postoperative day. We should identify high-risk patients in advance and make specific treatment plans according to the characteristics of their symptoms.

Computed tomography in suspected anastomotic leakage after colorectal surgery: evaluating mortality rates after false-negative imaging

PURPOSES

We sought to investigate the accuracy of abdominal CT scanning for anastomotic leakage and the effect of false-negative scans on the delay in therapeutic intervention and clinical outcome.

METHOD

Data from a prospectively bi-institutionally maintained database of all patients who underwent elective colorectal surgery with primary anastomosis for malignant or benign disease between 2010 and 2017 were reviewed. Patients with confirmed anastomotic dehiscence at reintervention who underwent a postoperative CT scan for suspected leakage were identified and radiological reports were retrieved.

RESULTS

Seventy-six patients with anastomotic dehiscence were included in the study. American Society of Anesthesiologists score, sex, type of surgical procedure, malignancy, and type of anastomosis do not correlate with postoperative false-negative CT imaging. Postoperative false-negative CT scan, however, led to delayed reintervention (3 vs. 6 h, p = 0.023) and increased mortality (five deaths vs. no deaths, p = 0.043). Free abdominal air (p = 0.001) and extraluminal contrast extravasation (p = 0.001) were found to be predictive of accuracy in anastomotic leakage diagnosis.

CONCLUSION

The suboptimal specificity of a postoperative CT scan in suspected anastomotic leakage after colorectal surgery can delay reintervention and increase mortality.

Radiographic Findings of Anastomotic Leaks

Although computed tomography (CT) scans play an important role in the diagnosis and management of anastomotic leaks (AL), there is no consensus on what radiographic findings are associated with AL. The purpose of this study is to identify the most common CT scan findings associated with AL and whether the amount of extraluminal air or the density of extraluminal fluid can be correlated with the presence of an AL. A retrospective chart review of 210 patients with anastomotic leaks from 2003 to 2010 at Mount Sinai Medical Center was performed. Eighty-six patients fit our criteria and were included. All CT scans were reread by an independent radiologist not involved with patient care. Our study included 59 per cent men and 41 per cent women with a mean age of 51 years. Diagnoses included inflammatory bowel disease (53%), malignancy (21%), and diverticulitis (12%). One hundred per cent of the patients had one of three findings: extraluminal air (92%), extraluminal fluid (88%), or extravasation of contrast (32%). Eighty-one per cent (70/86) had both fluid and air simultaneously. Extraluminal air was seen in 79 patients. The estimated amounts of extraluminal air were as follows: 0 to 25 mL (49%), 26 to 500 mL (41%), 500 to 1000 mL (5%), and more than 1000 mL (5%). The Hounsfield unit (HU) measurements of the fluid ranged from 3 to 633 HUs. The most common CT findings associated with AL are pneumoperitoneum and extraluminal fluid, including extravasation of contrast, which can be seen in up to 100 per cent of patients. The amount of estimated extraluminal air and density of fluid collection have no prognostic value in predicting AL.

Bowel and Bladder Injury Repair and Follow-up After Gynecologic Surgery

Bowel and bladder injuries are relatively rare, but there can be serious complications of both open and minimally invasive gynecologic procedures. As with most surgical complications, timely recognition is key in minimizing serious patient morbidity and mortality. Diagnosis of such injuries requires careful attention to surgical entry and dissection techniques and employment of adjuvant diagnostic modalities. Repair of bowel and bladder may be performed robotically, laparoscopically, or using laparotomy. Repair of these injuries requires knowledge of anatomic layers and suture materials and testing to ensure that intact and safe repair has been achieved. The participation of consultants is encouraged depending on the primary surgeon's skill and expertise. Postoperative care after bowel or bladder injury requires surveillance for complications including repair site leak, abscess, and fistula formation.

Radiographic Evidence of Soft-Tissue Gas 14 Days After Total Knee Arthroplasty Is Predictive of Early Prosthetic Joint Infection

OBJECTIVE. The diagnosis of early prosthetic joint infection (PJI)-defined as within 6 weeks after a total knee arthroplasty (TKA)-can be difficult because of expected postsurgical changes and elevated inflammatory markers. The role of radiographic evaluation in this situation carries unclear clinical significance. This study had three primary aims: first, to determine when soft-tissue gas is no longer an expected postoperative radiographic finding; second, to determine whether soft-tissue gas is predictive of early PJI; and, third, to determine whether the presence of soft-tissue gas correlates with specific patient characteristics and microbiology culture results. MATERIALS AND METHODS. This retrospective study was of patients who underwent TKA from 2008 to 2018 with available imaging between 5 days and 6 weeks after TKA and no interval intervention before imaging. All confirmed early PJIs were included (n = 24 cases; 15 patients). For comparison, patients who underwent TKA but did not have a PJI (n = 180 cases; 150 patients) were selected randomly. Radiographs were reviewed by two readers. A two-tailed p < 0.05 was considered significant. RESULTS. Soft-tissue gas was identified on postoperative radiography of 13 of 24 (54.2%) cases (mean ± standard error of the mean [SEM], 28.3 ± 2.3 days after TKA) with early PJI and four of 180 (2.2%) cases (mean ± SEM, 15.3 ± 7.3 days after TKA) without PJI (p < 0.0001; odds ratio, 52.0 [95% CI, 14.7-156.9]). The presence of soft-tissue gas on radiography 14 days after TKA had a sensitivity of 0.54 (95% CI, 0.35-0.72) and specificity of 0.99 (95% CI, 0.97-1.00) for early PJI. Staphylococcus species were the dominant organisms; cases with soft-tissue gas showed a wider variety of microbiology species (p < 0.01). CONCLUSION. Postoperative soft-tissue gas present on radiography performed 14 days or more after TKA is predictive of early PJI and is associated with a wider spectrum of microorganisms.

Pneumoperitoneum

Pneumoperitoneum, usually seen as free air under the diaphragm, is a finding that can be seen on plain abdominal radiographs, signifying a leakage of air, usually from a perforation in the gastrointestinal tract. There are several other potential pathways from other body compartments for air to enter the abdominal cavity. Pneumoperitoneum does not always signify bowel rupture, as it can also result from pneumomediastinum and pneumothorax, and in patients who are being mechanically ventilated. Patient history and physical examination can assist in a preliminary diagnosis before diagnostic imaging. Plain chest/abdominal radiograph or computed tomographic scan of the abdomen can be diagnostic of pneumoperitoneum. Surgical versus nonsurgical conservative observation is determined on the basis of the cause and amount of free air.

Secondary peritonitis: principles of diagnosis and intervention

Secondary peritonitis accounts for 1% of urgent or emergent hospital admissions and is the second leading cause of sepsis in patients in intensive care units globally. Overall mortality is 6%, but mortality rises to 35% in patients who develop severe sepsis. Despite the dramatic growth in the availability and use of imaging and laboratory tests, the rapid diagnosis and early management of peritonitis remains a challenge for physicians in emergency medicine, surgery, and critical care. In this article, we review the pathophysiology of peritonitis and its potential progression to sepsis, discuss the utility and limitations of the physical examination and laboratory and radiographic tests, and present a paradigm for the management of secondary peritonitis.

Natural History of Pneumoperitoneum After Laparotomy: Findings on Multidetector-Row Computed Tomography

BACKGROUND

Postoperative pneumoperitoneum after abdominal surgery represents a diagnostic challenge. This study was designed to analyze the appearance of pneumoperitoneum on computed tomography after uncomplicated abdominal surgery through laparotomy.

METHODS

The database of the department of digestive surgery was retrospectively queried to identify all patients who underwent abdominal surgery through laparotomy during a 13-month period. This initial search retrieved a total of 384 consecutive patients. Criteria for inclusion in this study were: (a) the operation was performed in our institution, (b) the patient had computed tomography examination postoperatively, and (c) the patient had no postoperative grade ≥3 complication.

RESULTS

Postoperative pneumoperitoneum was visible in 38/80 patients (47.5 %), with a mean volume of 15 ± 22.8 (SD) cm³ and multiple locations in 32/38 patients (84 %). Postoperative pneumoperitoneum was observed in 22/26 patients (85 %) until day 5 postoperative, 14/34 patients (41 %) between day 6 and day 15 postoperative, and in 2/21 patients (9.5 %) after day 15 postoperative. Its volume decreased when the time interval between surgery and computed tomography increased. Results of multivariate analysis showed that the time interval between surgery and computed tomography was the single independent variable that was associated with the presence of postoperative pneumoperitoneum.

CONCLUSIONS

Postoperative pneumoperitoneum is a frequent finding on computed tomography in the early period following abdominal surgery and commonly with multiple locations. Although commonly observed before day 5 postoperative, its presence must be considered as an alarming finding after day 7 postoperative, if present in a single location with a volume >20 cm³.

[Characteristics of postoperative peritonitis]

Postoperative peritonitis is still a life-threatening complication after abdominal surgery and approximately 10,000 patients annually develop postoperative peritonitis in Germany. Early recognition and diagnosis before the onset of sepsis has remained a clinical challenge as no single specific screening test is available. The aim of therapy is a rapid and effective control of the source of infection and antimicrobial therapy. After diagnosis of diffuse postoperative peritonitis surgical revision is usually inevitable after intestinal interventions. Peritonitis after liver, biliary or pancreatic surgery is managed as a rule by means of differentiated therapy approaches depending on the severity.

Two similar cases of elderly women with moderate abdominal pain and pneumoperitoneum of unknown origin: a surgeon's successful conservative management

Patients presenting with abdominal pain and pneumoperitoneum in radiological examination usually require emergency explorative laparoscopy or laparotomy. Pneumoperitoneum mostly associates with gastrointestinal perforation. There are very few cases where surgery can be avoided. We present 2 cases of pneumoperitoneum with unknown origin and successful conservative treatment. Both patients were elderly women presenting to our emergency unit, with moderate abdominal pain. There was neither medical intervention nor trauma in their medical history. Physical examination revealed mild abdominal tenderness, but no clinical sign of peritonitis. Cardiopulmonary examination remained unremarkable. Blood studies showed only slight abnormalities, in particular, inflammation parameters were not significantly increased. Finally, obtained CTs showed free abdominal gas of unknown origin in both cases. We performed conservative management with nil per os, nasogastric tube, total parenteral nutrition and prophylactic antibiotics. After 2 weeks, both were discharged home.

Image-guided percutaneous drainage vs. surgical repair of gastrointestinal anastomotic leaks: is there a difference in hospital course or hospitalization cost?

PURPOSE

To identify differences in hospital course and hospitalization cost when comparing image-guided percutaneous drainage with surgical repair for gastrointestinal anastomotic leaks.

MATERIALS AND METHODS

A retrospective IRB-approved search using key words "leak" and/or "anastomotic" was performed on all adult CT reports from 2002 to 2011. CT examinations were reviewed for evidence of a postoperative gastrointestinal leak and assigned a confidence score of 1-5 (1 = no leak, 5 = definite leak). Patients with an average confidence score <4 were excluded. Type of surgery, patient data, method of leak management, number of hospital admissions, length of hospital stay, discharge disposition, number of CT examinations, number of drains, and hospitalization costs were collected.

RESULTS

One hundred thirty-nine patients had radiographic evidence of a gastrointestinal anastomotic leak (esophageal, gastric, small bowel or colonic). Nine patients were excluded due to low confidence scores. Twenty-seven patients underwent surgical repair (Group A) and 103 were managed entirely with percutaneous image-guided drainage (Group B). There was no significant difference in patient demographics or number of hospital admissions. Patients in Group A had longer median hospital stays compared to Group B (48 vs. 32 days, p = 0.007). The median total hospitalization cost for Group A was more than twice that for Group B ($99,995 vs. $47,838, p = 0.001). Differences in hospital disposition, number of CT examinations, number of drains, and time between original surgery and first CT examination were statistically significant.

CONCLUSION

Gastrointestinal anastomotic leaks managed by percutaneous drainage are associated with lower hospital cost and shorter hospital stays compared with surgical management.

Tension Pneumoperitoneum Caused by Obstipation

Emergency physicians are often required to evaluate and treat undifferentiated patients suffering acute hemodynamic compromise (AHC). It is helpful to apply a structured approach based on a differential diagnosis including all causes of AHC that can be identified and treated during a primary assessment. Tension pneumoperitoneum (TP) is an uncommon condition with the potential to be rapidly fatal. It is amenable to prompt diagnosis and stabilization in the emergency department. We present a case of a 16-year-old boy with TP to demonstrate how TP should be incorporated into a differential diagnosis when evaluating an undifferentiated patient with AHC.

Is CT cystography an accurate study in the evaluation of spontaneous perforation of augmented bladder in children and adolescents?

BACKGROUND

Spontaneous bladder perforation (SBP) is a potentially fatal complication of augmented bladder. Imaging is often used for diagnosis. In this study we present our experience with CT cystography (CTC) in the diagnosis of SBP.

OBJECTIVE

To determine CTC accuracy in the evaluation of SBP in children with an augmented bladder.

STUDY DESIGN

The institutional review board approved this HIPAA-compliant study; informed consent was waived. All patients under 20 years old, who underwent CTC for SBP evaluation from 2003 to 2013, were identified. Two radiologists independently reviewed CTC studies for contrast extravasation, ascites, and pneumoperitoneum. Ascites was graded: small - confined to the rectovesical pouch (RVP); moderate - beyond the RVP; large - beyond the pelvis.

RESULTS

Eighty-nine patients (47 males, age 4.2-19.8 years) had 132 CTCs. SBP was diagnosed in 14% (19/132). Both radiologists found contrast extravasation in 74% (14/19) of patients with SBP; two patients had only pneumoperitoneum, and three had only ascites (large = 2, moderate = 1) (Fig.). SBP was found in 1% of CTCs with no ascites or small ascites (1 of 98 and 92; radiologists 1 and 2, respectively). Findings of extraluminal extravasation, unexplained pneumoperitoneum, or large ascites, yielded a detection rate of 95% for SBP by each radiologist. In eight patients, small bowel obstruction was diagnosed.

DISCUSSION

Contrast extravasation was detected in only 74% of patients with SBP. The use of indirect signs of perforation (unexplained pneumoperitoneum and large ascites) in addition to contrast extravasation, increased the detection rate of SBP to 95%. US screening for SBP and selection of patients with moderate or large ascites for CTC, may eliminate the need for most CT scans. In the absence of SBP, other abdominal abnormalities should be evaluated. Bowel obstruction was the most common non-urological emergency detected in this series. The main limitations of the study are: the small number of SBP cases; the diagnosis of SBP not based on surgical findings in three patients; and inability to completely exclude occult SBP in patients not explored surgically.

CONCLUSION

Extraluminal contrast was seen on CTC in most cases of SBP, but some patients with sealed bladder perforation had only pneumoperitoneum or moderate/large ascites. Therefore, SBP should be suspected in any patient with moderate/large volumes of pelvic fluid or unexplained pneumoperitoneum, even when there is no evidence of contrast extravasation. Patients with no ascites, or small volumes, are unlikely to have SBP; therefore, US can be used to screen low risk patients.

Pneumomediastinum and pneumoperitoneum on computed tomography after peroral endoscopic myotomy (POEM): postoperative changes or complications?

BACKGROUND

Many of the acute alterations after peroral endoscopic myotomy (POEM) may be of little clinical significance, while others may herald major clinical problems. The question whether pneumomediastinum/pneumoperitoneum is a normal postoperative finding after POEM, or should be regarded as a sign of a complication needs to be evaluated. Familiarity with these findings in computed tomography (CT) is essential for radiologists.

PURPOSE

To evaluate whether or not pneumomediastinum/pneumoperitoneum detected by chest CT is a sign of a complication after POEM using CO2 insufflation for esophageal achalasia.

MATERIAL AND METHODS

One hundred and eight patients with esophageal achalasia who underwent chest CT within 30 hours after POEM were included. CT findings were retrospectively reviewed by two radiologists in consensus. The correlation between pneumomediastinum and/or pneumoperitoneum shown on CT and the development of complications was analyzed.

RESULTS

Abnormal findings were identified on post-treatment CT, including pneumomediastinum and/or pneumoperitoneum (53.7%, 58/108), pneumothorax (0.9%, 1/108), subcutaneous emphysema (29.6%, 32/108), pleural effusion (69.4%, 75/108), segmental atelectasis of lung tissue (29.6%, 32/108), minor inflammation of lungs (69.4%, 75/108), and ascites (0.9%, 1/108). Pneumomediastinum and pneumoperitoneum were observed simultaneously in 29 cases. The incidence rate of mild complications was high (79.6%, 86/108), while the rate of severe complications was low (2.8%, 3/108). There was no significant correlation between the occurrence of pneumomediastinum and/or pneumoperitoneum on CT and the development of complications (P = 0.542), or the development of severe complications including delayed hemorrhage, esophageal perforation, and retroperitoneal abscess.

CONCLUSION

Pneumomediastinum and pneumoperitoneum detected by CT occur frequently after POEM and may be regarded as normal postoperative changes.

Postoperative pneumoperitoneum: is it normal or pathologic?

BACKGROUND

Pneumoperitoneum on computed tomography (CT) after abdominal surgery is common, but its incidence, duration, and clinical significance is widely debated.

MATERIALS AND METHODS

A retrospective, cohort study of patients who underwent abdominal CT within 30 days of abdominal surgery.

RESULTS

Among 344 patients, pneumoperitoneum was found in 39% (135/344) of patients on postoperative days 0-6 in 53%, 7-13 in 41%, 14-20 in 23%, 21-27 in 13%, and 28-30 in 0%. Pneumoperitoneum was associated with the presence of a drain (P = 0.014) but not with age, gender, body mass index, smoking history, lung disease, or open versus laparoscopic surgery (P > 0.05 for all variables). Eight patients required intervention (6%), most commonly for anastomotic leak (4 patients, 50%).

CONCLUSIONS

Postoperative pneumoperitoneum on abdominal CT can be seen in up to 23% of patients 3-weeks postoperatively; however, only 6% of the patients required intervention emphasizing the typically benign consequences of postoperative free air.

Common postoperative findings unique to laparoscopic surgery

The interpretation of images obtained in patients who have recently undergone abdominal or pelvic surgery is challenging, in part because procedures that were previously performed with open surgical techniques are increasingly being performed with minimally invasive (laparoscopic) techniques. Thus, it is important to be familiar with the normal approach used for laparoscopic surgeries. The authors describe the indications for various laparoscopic surgical procedures (eg, cholecystectomy, appendectomy, hernia repair) as well as normal postoperative findings. For example, port site hernias are more commonly encountered in patients with trocar sites greater than 10 mm and occur at classic entry sites (eg, the periumbilical region). Similarly, preperitoneal air can be encountered postoperatively, often secondary to trocar dislodgement during difficult entry or positioning. In addition, intraperitoneal placement of mesh during commonly performed ventral or incisional hernia repairs typically leads to postoperative seroma formation. Familiarity with normal findings after commonly performed laparoscopic surgical procedures in the abdomen and pelvis allows accurate diagnosis of common complications and avoidance of diagnostic pitfalls.

Pictorial review of normal postoperative cross-sectional imaging findings and infectious complications following laparoscopic appendectomy

Laparoscopic appendectomy is increasingly accepted as the preferred surgical treatment for acute appendicitis and represents one of the most common emergency operations performed in both adult and paediatric populations. However, in patients with perforated appendicitis laparoscopy is associated with an increased incidence of postoperative intraabdominal infections compared to open appendectomy. Nowadays urgent imaging is commonly requested by surgeons when postoperative complications are suspected. Due to the widespread use of laparoscopy, in hospitals with active surgical practices clinicians and radiologists are increasingly faced with suspected postappendectomy complications. This pictorial essay illustrates the normal cross-sectional imaging findings observed shortly after laparoscopic appendectomy and the spectrum of appearances of iatrogenic intraabdominal infections observed in adults and adolescents, aiming to provide radiologists with an increased familiarity with early postoperative imaging. Emphasis is placed on the role of multidetector CT, which according to the most recent World Society of Emergency Surgery (WSES) guidelines is the preferred and most accurate modality to promptly investigate suspected intraabdominal infections and highly helpful for correct therapeutic choice, particularly to identify those occurrences that require in-hospital treatment, drainage or surgical reintervention. In teenagers and young adults MRI represents an attractive alternative modality to detect or exclude iatrogenic abscesses without ionising radiation.

Teaching points

• Laparoscopic appendectomy is the preferred surgical treatment for uncomplicated acute appendicitis

• In perforated appendicitis laparoscopy results in increased incidence of intraabdominal infections

• Multidetector CT promptly assesses suspected iatrogenic intraabdominal infections

• Interpretation of early postoperative CT requires knowledge of normal postsurgical imaging findings

• Postsurgical infections include right-sided peritonitis, intraabdominal, pelvic or liver abscesses

CT scan-based modelling of anastomotic leak risk after colorectal surgery

AIM

Prolonged ileus, low-grade fever and abdominal discomfort are common during the first week after colonic resection. Undiagnosed anastomotic leak carries a poor outcome and computed tomography (CT) scan is the best imaging tool for assessing postoperative abdominal complications. We used a CT scan-based model to quantify the risk of anastomotic leak after colorectal surgery.

METHOD

A case-control analysis of 74 patients who underwent clinico-radiological evaluation after colorectal surgery for suspicion of anastomotic leak was undertaken and a multivariable analysis of risk factors for leak was performed. A logistic regression model was used to identify determinant variables and construct a predictive score.

RESULTS

Out of 74 patients with a clinical suspicion of anastomotic leak, 17 (23%) had this complication confirmed following repeat laparotomy. In multivariate analysis, three variables were associated with anastomotic leak: (1) white blood cells count > 9 × 10(9) /l (OR = 14.8); (2) presence of ≥ 500 cm(3) of intra- abdominal fluid (OR = 13.4); and (3) pneumoperitoneum at the site of anastomosis (OR = 9.9). Each of these three parameters contributed one point to the risk score. The observed risk of leak was 0, 6, 31 and 100%, respectively, for patients with scores of 0, 1, 2 and 3. The area under the receiver operating characteristic curve for the score was 0.83 (0.72-0.94).

CONCLUSION

This CT scan-based model seems clinically promising for objective quantification of the risk of a leak after colorectal surgery.

Imaging of complications associated with port access of abdominal laparoscopic surgery

Advanced techniques and equipment in laparoscopic surgery offer advantages over open surgery, expanding the application of this minimally invasive procedure to a wide range of abdominal operations that used to be performed as an open procedure. Laparoscopic surgery is performed in the closed abdominal cavity in which the space is limited. To create a working space in the abdominal cavity, an artificial pneumoperitoneum is established and multiple ports are placed for the introduction of various laparoscopic instruments. Unlike open surgery in which the incision is made just above the target organ, laparoscopic access is made away from the area of dissection, with the instruments triangulated around the target organ within the abdomen. This fundamental difference in approach between the open and laparoscopic procedures may lead to peculiar postoperative complications after laparoscopic surgery, which may be present away from the target organ or in the abdominal wall, and be easily missed on postoperative imaging studies. These complications include port-related direct organ injuries, such as abdominal organ or vascular injury; abdominal wall complications related to laparoscopic port insertion such as vascular injury, infection, and hernia; abdominal wall complications related to specimen removal, such as port site tumor seeding and endometriosis; and complications related to gas insufflation. The radiologist plays an important role in the diagnosis of complications after laparoscopic surgery, and therefore should be familiar with the features of such complications on imaging scans in the era of laparoscopic surgeries.

Use of computed tomography in the diagnosis of bowel complications after gynecologic surgery

OBJECTIVE

To determine factors predictive of bowel complications after gynecologic surgery and establish the added utility of computed tomography (CT) in the diagnostic process.

METHODS

Patients who underwent gynecologic surgery between January 2, 2008, and December 30, 2010, who had CT scans of the abdomen, pelvis, or abdomen and pelvis within 42 days for a suspected bowel complication were identified. Logistic regression analysis was used to identify factors predictive of bowel-related complications. The diagnostic accuracy of CT was compared among patient risk groups based on clinical suspicion (pretest probability) of bowel complications.

RESULTS

Among 205 eligible patients, 38 (18.5%) patients had a bowel-related complication. Mean time from surgery to CT was 12.4 (10.1) days. Clinical characteristics were used to develop a clinical model that included unexpected drainage from the drain, wound, or stoma (adjusted odds ratio [OR] 26.3, 95% confidence interval [CI] 3.1-224.4, P=.003), coronary artery disease (OR 10.7, CI 1.4-80.9, P=.022), laparotomy (compared with minimally invasive surgery) (OR 4.4, CI 1.1-17.2, P=.032), and age older than 45 years (OR 2.4, CI 0.7-8.8, P=.18). Addition of CT to clinical evaluation increased the predictive ability of the model (area under the curve) from 0.73 to 0.99. Among 57 low-risk patients, three with confirmed bowel-related complications would have been missed if CT was not performed. Among 13 high-risk patients, CT sensitivity was 70%, and it was negative for bowel complications in three patients subsequently confirmed to have serious complications (one anastomotic leak, two bowel perforations).

CONCLUSIONS

In patients who have undergone gynecologic surgery and have a high clinical probability of a postoperative bowel-related complication, CT alone may fail to accurately identify patients with serious complications.

LEVEL OF EVIDENCE

: II.

Diagnostic value of abdominal free air detection on a plain chest radiograph in the early postoperative period: a prospective study in 648 consecutive patients who have undergone abdominal surgery

BACKGROUND

To the best of our knowledge, this is the first study to evaluate the predictive value of free air (on a plain radiograph) for bowel perforation in a large prospective cohort of surgical patients.

METHODS

All consecutive patients undergoing abdominal surgery between January 2011 and June 2012 were screened for this study. We performed an upright chest radiograph on the second and third postoperative day. Thereafter, additional radiographic evaluations were performed every 2 days until the disappearance of abdominal free air.

RESULTS

Of the 648 subjects enrolled in our study, free abdominal air was found in 65 subjects on the first radiographic evaluation (2 days after surgery), 51 on the second (3 days after surgery), three on the third (5 days after surgery), and none on the fourth (7 days after surgery). The presence of free abdominal air was associated with an increased risk of gastrointestinal perforation. The presence of free air was associated with a hazard ratio (HR) of 21.54 (95% CI 9.66-48.01, p<0.001) and a HR of 23.87 (95% CI 10.68-53.34, p<0.001) at 2 and 3 days after surgery, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value were 70, 93, 33, and 98%, respectively, at 2 days after surgery, and similar results were confirmed at 3 days after surgery.

CONCLUSION

We believe that the presence of free air at 3 days after surgery should not be considered a common finding. Here, we demonstrate that the detection of free air has a remarkable predictive value for gastrointestinal perforation, which has been overestimated in previous experience.

Postoperative pneumoperitoneum: guilty or not guilty?

Purpose

The aim of this study was to determine the incidence and duration of postoperative pneumoperitoneum on plain radiographs and to identify the radiologic findings associated with anastomotic leakage.

Methods

A retrospective analysis was conducted on plain radiographs of 384 patients who underwent intra-abdominal anastomoses between March 2005 and December 2008.

Results

Of the 384 patients, 93 patients (24.2%) had postoperative pneumoperitoneums. Of the 93 patients, 86 patients (92.5%) had physiologic pneumoperitoneums and 7 patients (7.5%) had pneumoperitoneums associated with anastomotic leakage. The initial air height was significantly greater in the leakage group than the physiologic air group (12.16 ± 7.65 mm vs. 7.71 ± 5.08 mm, P = 0.04). The area under the receiver operating characteristic curve of the initial height of free air for anastomotic leakage was 0.69 (95% confidence interval, 0.59 to 0.78). The best cut-off point was 11.7 mm. The height of the pneumoperitoneum increased with time in the leakage group. Ileus was significantly more prevalent in the leakage group than the physiologic air group (P < 0.01).

Conclusion

Postoperative pneumoperitoneum is a common phenomenon after abdominal surgery. An initial air height >11.7 mm, increasing air height over time, and the presence of ileus on plain radiographs suggest a high likelihood of anastomotic leakage.

Pneumoperitoneum post-fluoroscopic percutaneous gastrojejunostomy insertion: computed tomography and clinical evaluation

INTRODUCTION

To assess the incidence and clinical significance of pneumoperitoneum after radiologic percutaneous gastrojejunostomy (PGJ) tube insertion.

METHODS

Sixteen subjects were prospectively assessed after imaging-guided PGJ tube insertion to discern the incidence of pneumoperitoneum related to specific clinical signs and symptoms. Computed tomography of the abdomen and the pelvis was performed immediately after PGJ insertion. A clinical evaluation, including history, general and abdominal physical examination, temperature, complete blood cell count, abdominal pain, and abdominal tension, was performed on days 1 and 3, and at the discretion of the nutritional support team on day 7 after PGJ insertion.

RESULTS

Fifteen of the 16 subjects demonstrated imaging findings of pneumoperitoneum after the PGJ-tube insertion. Only a small amount of pneumoperitoneum was demonstrated in 10 of the subjects, whereas a large volume of gas was detected in 2 of the subjects. The only altered clinical findings encountered were increased white blood cell count and fever. These abnormal clinical data were most frequently seen immediately after feeding-tube placement.

DISCUSSION

Pneumoperitoneum was a common finding after PGJ-tube placement in our study population. There were no statistically significant abnormal clinical parameters, in the presence or absence of pneumoperitoneum, for any of the subjects after PGJ-tube insertion. Conservative management of pneumoperitoneum after PGJ is warranted.

Tension pneumoperitoneum: innovative decompression of this general surgical emergency

We describe the novel use of a cannula in decompressing a large tension pneumoperitoneum secondary to perforated sigmoid diverticulum, in which the patient did not subsequently require an emergency laparotomy. Needle decompression was successfully used as part of a conservative regimen, thus avoiding potentially high-risk surgery.

Recurrent non-surgical pneumoperitoneum due to jejunal diverticulosis

BACKGROUND

The presence of free intraperitoneal gas usually warrants emergent surgery. In rare instances, however, non-surgical conditions such as jejunal diverticulosis can cause pneumoperitoneum and do not require intervention.

OBJECTIVES

The objective of this article is to provide the computed tomography (CT) scan findings of jejunal diverticulosis causing pneumoperitoneum. The article will also discuss other non-surgical causes of spontaneous pneumoperitoneum to increase awareness and avoid unnecessary surgery.

CASE REPORT

We describe a case of recurrent pneumoperitoneum due to jejunal diverticulosis in which the patient remained asymptomatic and free of complications with repeated evaluations in the emergency department over the course of 18 months.

CONCLUSION

Although spontaneous pneumoperitoneum due to jejunal diverticulosis is a rare finding, when it does occur, this condition must be distinguished from other forms of pneumoperitoneum to avoid unnecessary surgery. CT scan findings of multiple rounded, variably sized jejunal outpouchings filled with oral contrast are helpful in diagnosing jejunal diverticulosis and confirming the decision for conservative management of the patient.

Prolonged postlaparoscopy carbon dioxide pneumoperitoneum

In this article we report what is to our knowledge the longest published duration of postlaparoscopy CO2 pneumoperitoneum, and discuss factors that may contribute to the duration of postoperative pneumoperitoneum.

Intraperitoneal effects of extraperitoneal laparoscopic radical prostatectomy

OBJECTIVES

To compare routine radiologic and laboratory findings after extraperitoneal and transperitoneal laparoscopic radical prostatectomy (eLRP, tLRP) and assess relevant clinical correlations.

METHODS

Fifty consecutive eLRP and tLRP (laparoscopic and robot-assisted) were evaluated. Preoperative complete metabolic panel and complete blood count were determined, and these serum tests and amylase and lipase level measurements were repeated postoperatively. Ten consecutive eLRP and tLRP patients also underwent flat and upright abdominal x-rays. Operative time, perioperative complications, length of hospital stay, and amount of narcotic used were measured for each group.

RESULTS

On postoperative day 1, all eLRP patients evaluated (100%) had radiographic free air in the abdomen, as did 80% of the tLRP patients. Only 1 of 50 patients (2%) had elevated aspartate aminotransferase (eLRP), 2 of 50 (4%) had elevated alanine aminotransferase (both eLRP), and 4 of 50 (8%) had elevated amylase (3 eLRP, 1 tLRP). Postoperative narcotic usage (eLRP 25 +/- 3 mg versus tLRP 23 +/- 5 mg morphine equivalents) and operative times (eLRP 3.6 +/- 0.1 hours versus tLRP 3.8 +/- 0.1 hours) were similar between the groups. Length of hospital stay was lower in the eLRP compared with the tLRP group (1.9 +/- 0.1 days versus 2.2 +/- 0.1 days, P <0.05). Perioperative complications did not differ significantly between groups.

CONCLUSIONS

Extraperitoneal LRP and tLRP patients had comparable perioperative outcomes, and few had abnormal serum metabolic laboratory values postoperatively. Unexpectedly, abdominal free air was found in all eLRP patients evaluated radiographically on postoperative day 1, a finding that should be interpreted as normal and not specific for bowel injury in this context.

Computed tomography after radical pancreaticoduodenectomy (Whipple's procedure)

Whipple's procedure (radical pancreaticoduodenectomy) is currently the only curative option for patients with periampullary malignancy. The surgery is highly complex and involves multiple anastomoses. Complications are common and can lead to significant postoperative morbidity. Early detection and treatment of complications is vital, and high-quality multidetector computed tomography (MDCT) is currently the best method of investigation. This review outlines the surgical technique and illustrates the range of normal postoperative appearances together with the common complications.

CT assessment of anastomotic bowel leak

AIM

To evaluate the predictors of clinically important gastrointestinal anastomotic leaks using multidetector computed tomography (CT).

SUBJECTS AND METHODS

Ninety-nine patients, 73 with clinical suspicion of anastomotic bowel leak and 26 non-bowel surgery controls underwent CT to investigate postoperative sepsis. Fifty patients had undergone large bowel and 23 small bowel anastomoses. The time interval from surgery was 3-30 days (mean 10+/-5.9 SD) for the anastomotic group and 3-40 days (mean 14+/-11 SD) for the control group (p=0.3). Two radiologists blinded to the final results reviewed the CT examinations in consensus and recorded the presence of peri-anastomotic air, fluid or combination of the two; distant loculated fluid or combination of fluid and air; free air or fluid; and intestinal contrast leak. Final diagnosis of clinically important anastomotic leak (CIAL) was confirmed at surgery or by chart review of predetermined clinical and laboratory criteria.

RESULTS

The prevalence of CIAL in the group undergoing CT was 31.5% (23/73). The CT examinations with documented leak were performed 5-28 (mean; 11.4+/-6 SD) days after surgery. Nine patients required repeat operation, 10 percutaneous abscess drainage, two percutaneous drainage followed by surgery, and two prolonged antibiotic treatment and total parenteral nutrition (TPN). Of the CT features examined, only peri-anastomotic loculated fluid containing air was more frequently seen in the CIAL group as opposed to the no leak group (p=0.04). There was no intestinal contrast leakage in this cohort. Free air was present up to 9 days and loculated air up to 26 days without CIAL.

CONCLUSION

Most postoperative CT features overlap between patients with and without CIAL. The only feature seen statistically more frequently with CIAL is peri-anastomotic loculated fluid containing air.

Postoperative pneumoperitoneum: prevalence, duration, and possible significance

Free intraperitoneal air after abdominal surgery is a confounding finding with uncertain significance. A diagnostic dilemma often arises as to its origin: does it merely represent residual postoperative pneumoperitoneum (PP), which will need no intervention, or does it indicate a complication such as an anastomotic leak or a perforation of the gastrointestinal tract. Residual PP is usually well tolerated, as it will be absorbed over time and requires no therapy. On the other hand, air escaping through a gastrointestinal tract perforation or leak usually represents an intra-abdominal catastrophe requiring urgent intervention. This intriguing subject has been dealt with quite extensively based on plain film radiography findings in the past 50 years, and has lately also been studied on CT. This review discusses factors influencing the prevalence of PP and its range of duration.

Delayed post-operative pneumoperitoneum

We present a case of post-operative pneumoperitoneum (PP), which persisted for eight weeks. Postoperative retained air is the most common cause of PP. It does not require a surgical intervention and thus is defined as a 'non-surgical PP'. The etiological factors contributing to the duration of the postoperative PP are controversial but the longest time described in the literature is 24 days. We review the relevant literature and discuss factors contributing to the duration of postoperative PP.

Pneumoperitoneum after Rough Sexual Intercourse

Our objective is to report on a case of nonsurgical pneumoperitoneum and review the mechanism/gynecologic causes of such. We present a case report and review of the literature based on a MEDLINE search using the keywords pneumoperitoneum and nonsurgical. Radiographic evidence of free intraperitoneal air suggests hollow viscus rupture and usually warrants urgent surgical management. Findings of diffuse rebound tenderness and guarding solidify the decision for urgent surgical exploration. We present a case of a patient who presented with all of the above findings that subsequently underwent a negative laparotomy. On the day after surgery she admitted to having had rough sexual intercourse 3 days before presentation. Nonsurgical pneumoperitoneum has a number of unusual causes. Intra-abdominal, thoracic, gynecologic, iatrogenic, and miscellaneous etiologies are encountered. It was determined that the pneumoperitoneum in this case was secondary to rough sexual intercourse. We concluded that pneumoperitoneum secondary to nonsurgical causes represents a diagnostic dilemma. In the patient with free intraperitoneal air on plain X-ray one should be suspicious of less common nonsurgical etiologies. The majority of patients will require laparotomy. Thorough sexual and gynecologic/obstetrical history is a valuable adjunct in identifying the patient who does not.

Absorption of intraperitoneal CO2 after laparoscopy in piglets: an experimental study

PURPOSE

The aim of this study was to study the absorption time of CO(2) after laparoscopy in piglets.

METHODS

Laparoscopies were performed on 14 6-week-old piglets. The animals' abdomens were x-rayed immediately after closure 1, 1.5, and 2 hours postoperatively, and thereafter daily.

RESULTS

All CO(2) was absorbed completely within 1 day.

CONCLUSION

CO(2) absorption may follow a similar time course in small children. J Pediatr Surg 36:913-916.