1. Interval Appendectomy: Evaluating the necessity and cost effectiveness
Meera Kotagal, MD University of Washington, R3 October 20, 2011

2. Case Presentation: KLP
16 yo boy p/w 10 day h/o abdominal pain
Taken to the OR for appendectomy, found to have severe adhesions and 3 large abscess cavities
Drain placement intraop, treatment with IV abx
Initial length of stay 23 days
Interval appendectomy at 8 weeks
Post-op course uncomplicated, discharged on POD1
Pathology:
Appendix completely effaced by neutrophilic and lymphoplasmacytic inflammation filling the lumen, destroying the epithelium, tracking through the wall, and extending onto the serosa.
Granulation tissue formation that overlies an obvious perforation site, consistent with partial healing of this process.
WBC of 20 on presentation, 2+ ketones in U/A
U/s with multiple fluid collections in RLQ, largest 13.2 x 3.5 x 6.0, appendicolith, appendix not visualized
discharged on PO augmentin, had splenic collection that could not be drained

3. Epidemiology Estimated 250,000 cases per year in the US
Incidence 1-2 per 10,000 in children under age 4
Increases to per 10,000 in children over 4
Perforation occurs in 20-45% of cases
Most common operation in children requiring emergency surgery
Retrospective study of children using KID (Kid’s Inpatient Database) database and NIS (national inpatient sample) databases
cases of acute appendicitis, cases of perforated appendicitis - 46%

4. Non-operative management
Oliak et al, 2001:
Retrospective study of 155 patients
88 treated non-operatively, 67 treated operatively
No difference in length of stay or time to tolerating diet, normalization of WBC and temperature
Lower complication rate in non-operative group
Brown CV et al, 2003:
Retrospective review of 104 patients
36 treated operatively, 66 treated non-operatively
Lower overall length of stay in non-operative group
Oliak et al patients retrospective review between 1992 and 1998.
Non-operative group had lower complication rate 17 vs 36 percent (.008)
No difference in length of stay, tolerating diet, normalization of WBC, normalization of temperature (NEED TO PUT DATA IN NOTES SECTION)
Brown patients, 36 operatively, 55 non-operatively. Higher complcation rate (58 vs 15% - p 0.001)
Compications include abscess, wound infection, fistula, bacteremia
Lower overall LOS in non-operative group vs 10.7 days, p = includes time for interval appendectomy

5. Non-operative management
St. Peter et al, 2010
Randomized children to immediate appendectomy vs. percutaneous drainage and interval appendectomy
No differences in length of hospitalization, recurrent abscess, or overall charges
St. Peter - randomized trial in children
Children with CT defined abdominal abscesses were randomized to immediate lap appy or IV abx with perc drainage and interval apy
40 children
No differences in LOS, recurrent abscess rates, or overall charges
Trend toward longer operating time in patients with initial appendectomy (61 vs 42 minutes, p = 0.06)
4 patients (20%) failed initial non-operative management, 6 did not have drain placed b/c not accessible by IR
Bowel obstruction, progressing peritonitis, persistent fever and abscess, nausea/emesis
Had previous retrospective trial with 17% of recurrent abscess in non-op with interval appendectomy
Mean charges $44,195 and $44,687 in the two groups - no difference in hospital days

6. Non-operative management
Schurman et al, 2011
Examined QOL for immediate appendectomy vs interval appendectomy
Randomized controlled trial
At 12 weeks, trend to poorer QOL in children
Increase in parenting stress at 12 weeks in interval appy group
PedsQL used to assess pediatric QOL, Pediatric Illness Inventory (PIP) assesses parenting stress a/w illness of dependent child
Randomized in groups of 4
12 weeks - PedsQL - initial op 96.77, initial non-op 84.37
12 weeks - PIP - initial op 49.6, initial non-op p< 0.05

7. Interval Appendectomy
Puapong et al, 2007
Retrospective cohort study
12 regional acute-care hospitals
6439 patients
Risk of recurrent appendicitis 8% in non-operative group
Adult arm included 32K patients
Pediatric sub-study included 6439 patients
12 acute care hospitals, , mean length of f/u 7.5 years
72 managed non-operatively - 11 underwent IA, 61 were followed
8% of 61 (5 children) developed recurrent appendicitis
Age, sex, type of appendicitis (abscess, peritonitis, etc.), drainage had no effect on risk of recurrence
LOS was 6.6 days
80% of recurrences occur within 6 months
Another study - Ein et al x RR of recurrence if appendicitis a/w appendicolith
Puapong D, Lee SL, Haigh PI et al. Routine interval appendectomy in children is not indicated. J Ped Surg. 2007; 42:

8. Interval Appendectomy
Histopathological evaluation of appendix
162 patients with appendicitis, 18 underwent interval appy
17 appendices evaluated:
Normal = 4
Normal with mild serositis = 6
Acute appendicitis = 2
Unusual findings (Meckel’s, granulomatous appendix, duplication of appendix) = 5
54 patients treated non-operatively, 32 underwent appendectomy
32 appendices evaluated:
Normal = 11
Wall thickening/fibrosis = 8
Lumen obliterated = 2
Acute/subacute appendicitis = 6
Chronic inflammation = 6

9. Cost-Effectiveness Raval et al, 2010
Decision tree analysis for continued observation vs. interval appendectomy
Population 0-18 year olds
Determined outcome probabilities from literature review
Population assumed to be 0-18 year olds successfully managed non-operatively for perforated, localized appendicitis
Determined outcome probabilities for each decision point from literature review
Those undergoing interval appy were stratified into complicated and noncomplicated post-op course
Largest study children - complication rate 2.3% for interval appy
Probability of success for continued non-operative management varies from 57-92%
Cost figures from KID database - 58,257 children in kid database
Assumed successful observation would cost $2000 including office visits
Assumed pain and fever would lead to additional costs - $4000
If probability of successful observation was estimated at 0.85
Cost saving for continued non-operative observation
Observation arm estimated at $ and interval appy arm at $
Using sensitivity analyses - cost savings are expected as long as probability of successful observation is >= 60%
Raval MV, Lautz T, Reynold M et al. Dollars and sense of interval appendectomy in children: a cost analysis. J Ped Surg. 2010; 45:

10. Cost-Effectiveness Costs estimated from KID database
Continued non-operative = $
Interval appendectomy = $
Sensitivity analyses of probability of
successful observation and cost of
successful observation
If probability of successful observation was estimated at 0.85
Cost saving for continued non-operative observation
Observation arm estimated at $ and interval appy arm at $
Using sensitivity analyses - cost savings are expected as long as probability of successful observation is >= 60%

11. Conclusions Routine interval appendectomy may not indicated
Low recurrence rate
Increased costs/hospital days
Data quality is poor, not generalizable
Certain patient-specific factors may increase benefit of interval appendectomy
Appendicitis associated with an appendicolith
Reliability of family and proximity to hospital
Time away from work
Quality of life for patient and parents
Rate of recurrence is low, severity is no worse, LOS is actually shorter for recurrence vs interval appy
Another study - Ein et al x RR of recurrence if appendicitis a/w appendicolith
Not doing interval appy may allow patients/family to have less stress

12. References
Brown CVR, Abrishami M, Muller M et al. Appendiceal Abscess: Immediate Operation or Percutaneous Drainage? Am Surg. 2003; 69:
Ein SH, Shandling B. Is interval appendectomy necessary after rupture of an appendiceal mass? J Ped Surg. 1996; 31:
Gahukamble DB and Gahukamble LD. Surgical and Pathological Basis for Interval Appendicectomy After Resolution of Appendicular Mass in Children. J Ped Surg. 2000; 35:424-7.
Mazziotti MV, Marley EF, Winthrop PT et al. Histopathologic Analysis of Interval Appendectomy Specimens: Support for the Role of Interval Appendectomy. J Ped Surg. 1997; 32:806-9.
Keckler SJ, Tsao K, Sharp SW et al. Resource utilization and outcomes from percutaneous drainage and interval appendectomy for perforated appendicitis with abscess. J Ped Surg. 2008; 43:
Oliak D, Yamini D, Udani VM et al. Initial Nonoperative Management for Periappendiceal Abscess. Dis Colon Rectum. 2001; 44:
Puapong D, Lee SL, Haigh PI et al. Routine interval appendectomy in children is not indicated. J Ped Surg. 2007; 42:
Raval MV, Lautz T, Reynolds M et al. Dollars and sense of interval appendectomy in children: a cost analysis. J Ped Surg. 2010; 45:
Schurman JV, Cushing CC, Garey CL et al. Quality of life assessment between laparoscopic appendectomy at presentation and interval appendectomy for perforated appendicitis with abscess: analysis of a prospective randomized trial. 2011; 46:
St. Peter SD, Aguayo P, Fraser JD et al. Initial laparoscopic appendectomy versus initial nonoperative management and interval appendectomy for perforated appendicitis with abscess: a prospective, randomized trial. J Ped Surg. 2010; 45:

14. Recurrence