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Original research
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Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study
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Helen Pham*, Michael Devadas, Julie Howle Department of Surgery, Westmead Hospital, Corner of Darcy and Hawkesbury Rd, Westmead, NSW, Australia
h i g h l i g h t s
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We examined the accuracy of intraoperative macroscopic assessment of the appendix in correlation to the experience of the operator and the gender of the patient. The diagnostic accuracy amongst junior trainees, senior trainees and consultants did not differ with accuracy rates of 85%, 81.6% and 88.2% respectively. The false negative rate was higher in females than in males (19.1% versus 7.2%; P ¼ 0.007). The false positive rate was higher in males than in female patients (43.3% versus 22.2%; P ¼ 0.05). We recommend that an appendicectomy be performed when clinically indicated regardless of macroscopic appearance.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 11 January 2015 Received in revised form 13 February 2015 Accepted 24 February 2015 Available online xxx
Background: We aimed to determine whether intraoperative macroscopic assessment of the appendix improves with surgical experience and whether the accuracy of the intraoperative assessment of the appendix is different in respect to sex of the patient. Methods: Medical records of all appendicectomies performed during an 18-month period (2011e2012) at Westmead Hospital, Australia were reviewed. Accuracy of intraoperative macroscopic description correlating to histopathology was compared between groups based on the training level of the surgeon. Results: Correlation between the intraoperative diagnosis and final histopathology result was 83.5% of the 303 cases. The diagnostic accuracy amongst junior trainees, senior trainees and consultants did not differ with accuracy rates of 85%, 81.6% and 88.2% respectively, (P ¼ 0.44). The false negative rate was higher in females than in males (19.1% versus 7.2%; P ¼ 0.007). Conclusions: Our findings demonstrated that operator experience does not affect the accuracy of the intraoperative assessment of appendixes. We recommend that an appendicectomy be performed when clinically indicated regardless of macroscopic appearance. © 2015 Published by Elsevier Ltd on behalf of Surgical Associates Ltd.
Keywords: Appendectomy Histopathology Appendicitis Training Laparoscopic
1. Introduction Appendicectomy for acute appendicitis is one of the most common surgical procedures performed in hospitals [1,2], with approximately 22,000 operations undertaken in Australia in 2010e2011 [3]. However, a reported 15e30% of normal appendixes are removed, suggesting inaccuracy of intraoperative assessment of the appendix [4,5]. There is concern existing about the ability of surgeon to reliably detect abnormal pathological findings of the appendix intraoperatively [6e8] with current literature reporting
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* Corresponding author. 56 Simpson Rd, Bonnyrigg Heights, NSW 2177, Australia. E-mail address: [email protected] (H. Pham).
negative predictive value between 54.4% [6] and 74% [9] in open appendicectomy, and 41% [10] and 97% [11] in laparoscopic appendicectomy, questioning the ability of surgeons to adequately distinguish a normal appendix from an inflamed appendix. The question of whether or not to leave a normal looking appendix in place, has been widely disputed and a consensus has yet to be reached with some advocating for the removal of the appendix due to the potential of missed appendicitis [6,12], and others suggesting it is safe to leave in in situ [13,14]. Some authors advocate the removal of a normal looking appendix only in the context that there is no other existing explanatory pathology [15e17]. Previous studies have highlighted the low diagnostic accuracy rates in women (60%) when compared to males [18], which may be due to conditions that mimic appendicitis such as gynaecological
http://dx.doi.org/10.1016/j.ijsu.2015.02.019 1743-9191/© 2015 Published by Elsevier Ltd on behalf of Surgical Associates Ltd.
Please cite this article in press as: H. Pham, et al., Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.02.019
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abnormalities resulting in a higher incidence of false positive diagnosis in the female population [19]. High false negative rates of 18.6% reported in a retrospective study also raises concerns of the increased risks of perforations and abscess formation if the macroscopically normal but histological abnormal appendix was left in situ [19]. Trainee surgeons play an integral role in the assessment and management of patients especially in large teaching hospitals under the supervision of experienced consultants. Laparoscopic appendicectomy has been generally considered a safe procedure for trainees with a study finding no difference in operative time and morbidity compared to qualified surgeons [20], whereas another study has reported an increase surgical operative times and complications when surgical trainees are involved [21]. However the ability of surgical trainees to make an accurate intraoperative diagnosis of appendicitis has not been fully evaluated. We aimed to assess accuracy of the intraoperative assessment of the appendix in correlation to the histopathological diagnosis, and its association to surgeon experience and sex of the patient. 2. Methods Following ethics approval, we conducted a retrospective chart review of all patients who underwent an appendicectomy between January 1, 2011 and July 2012, at Westmead Hospital, a tertiary referral hospital in Sydney, Australia. Data was collected from patient medical records, operative theatre reports and histopathology reports. Patient demographics including sex, operative findings, operator details and final histological diagnosis were retrieved. Operative factors such as approach (open or laparoscopic) were noted. Patients who underwent incidental appendicectomy for reasons other than suspected appendicitis were excluded. One case where the operator was not documented on the report was excluded from the analysis. The intraoperative macroscopic description was retrieved from the operation report. For comparison between intraoperative and histopathological findings, the histological diagnosis was taken to be the gold standard. The extent of macroscopic disease documented by the surgeon was identified and categorised into the grades of appendicitis: inflamed, suppurative, gangrenous, and complicated (perforated/abscess) formation. Six cases described as being phlegmonous appendicitis were included within the category of complicated appendicitis. Findings documented by the surgeon or the pathologist as faecolith or fibrosis obliterans were not recorded as acute appendicitis. Additional operative findings documented by the surgeon were noted. The surgical level of the operating surgeon and assistant were reviewed, with the more senior surgeon who was scrubbed in identified as the main operator for this study. The Surgical Education & Training (SET) program is a recognised accredited five year surgical training program in Australia. Surgical Education & Training (SET) level was chosen as the standard of comparison was obtained for the surgeons involved during the time of the study. The grade of the operating surgeon was categorised as (1) Junior surgical trainees (senior Resident Medical Officer, SET 1 and 2); (2) Senior surgical trainees (SET 3, 4, and 5); and (3) Consultant level (Fellows and consultants). Senior resident medical officers included in the study were operators that were not affiliated with an accredited SET position and included unaccredited trainees. Based on these groupings, the accuracy of intraoperative macroscopic assessment of the appendix in correlation to histopathology was compared. Statistical analysis of comparison the groups and its statistical significance was performed using Statistical Package of Social Sciences version 21. The chi square test was used and probabilities less
than 0.05 were considered significant. A sample size estimate was calculated and required 555 patients in each group to reach a power of 0.8 and significance level of 0.05. However due to the retrospective nature of the study, we relied on available medical records to obtain our data. With our sample size, post hoc power analysis demonstrated that our study to have insufficient power to detect a significant difference between the three groups of surgical training levels (power ¼ 0.27) and between the male and female groups (power 0.38). 3. Results 3.1. Demographics Over the study period 303 patients underwent appendicectomy for suspected appendicitis, including 134 females and 169 males. The mean age of the study population was 30.9 years (age range 15e86 and 16e82 in females and males respectively). Appendicectomy was performed laparoscopically in the majority of cases (94.7%, 287/303), and an open approach was used in 16 patients, including nine cases which were converted from laparoscopy. 3.2. Analysis of intraoperative macroscopic assessment The macroscopic description of appendicitis documented by the surgeon was termed as inflamed/inflammation in 44.6% of cases (n ¼ 135), suppurative in 14.2% of cases (n ¼ 43), gangrenous in 2.8% (n ¼ 9) of cases and complicated appendicitis reported as perforation or abscess in 12.2% of cases (n ¼ 37). The overall accuracy of intraoperative macroscopic assessment of the appendix was 83.5% (253/303) with a positive predictive value (PPV) of 89.7% (201/224). The accuracy rate was 100% when findings of gangrenous appendicitis or complicated appendicitis such as perforation or abscess were described. When suppurative appendicitis was observed there was a 95.3% (41/43) correlation to a positive histopathology and when inflammation alone was observed, the PPV was 84.4% (114/135). The overall negative appendicectomy rate was 24.8% (75/303). Twenty three (10.3%) out of 224 patients who were deemed positive intraoperatively were found to have a normal appendix on microscopic examination. Seventy-nine cases were reported as being macroscopically normal with 27 (34.2%) demonstrating signs of appendicitis on histopathology. Preoperative imaging through CT and/or US was performed on 150 cases with radiological diagnosis of appendicitis in 90 of the cases (see Table 1). Of the 90 patients with preoperative imaging suggesting appendicitis, 2 cases were incorrectly diagnosed intraoperatively to have macroscopic signs of appendicitis. Conversely, of the 60 cases reported normal on preoperative imaging, 9 cases were described intraoperatively to be macroscopically normal, but
Table 1 Macroscopic assessment of the appendix in cases with preoperative radiological assessment (N ¼ 150). Histological assessment Appendicitis Radiological positive (n ¼ 90) Macroscopic positive Macroscopic negative Radiological negative (n ¼ 60) Macroscopic positive Macroscopic negative Total
Normal
Total
69 7
2 12
71 19
21 9 106
7 23 44
28 32 150
Please cite this article in press as: H. Pham, et al., Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.02.019
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histopathology demonstrated appendicitis.
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Table 3 Effect of surgical experience on the intraoperative diagnosis of appendicitis.
3.3. Analysis of macroscopic assessment in correlation to surgical experience
Intraoperative Grade of operating surgeon assessment Junior trainees Senior trainees N ¼ 60 N ¼ 174
The appendicectomies were performed by junior trainees in 60 cases; senior trainees in 174 cases; and consultants in 68 cases, (see Table 2). There was no significant difference in the accuracy of the intraoperative assessment of the appendix when comparing the experience of the operating surgeon, P ¼ 0.44 (see Table 3). Our results demonstrate that junior trainees, senior trainees and consultants obtained accuracy rates of 85% (95%CI: 73.9e91.9%), 81.6% (95%CI: 75.2e86.7%) and 88.2% (95%CI: 78.5e93.9%) respectively. The PPV was similar between all surgical training level groups with junior trainees accurately predicting appendicitis in 90.7% of cases (39/43; 95%CI: 78.4e96.3%). Although not statistically significant, the PPV was lower in senior trainees in 88.1% of cases (111/ 126; 95%CI: 81.3e92.7%) and higher in consultants with a PPV of 94.4% of cases (51/54; 95%CI: 84.9e98.1%), (P ¼ 0.42). The ability of correctly identifying a normal looking appendix was low across all groups with NPV of 70.6% in junior trainees, 64.6% in senior trainees and 64.3% in consultants (12/17, 31/48 and 9/14 respectively, p ¼ 0.9).
Accuracy % (95%CI) PPV % (95%CI) NPV % (95%CI) False positive rate (95%CI) False negative rate (95%CI)
Consultant level N ¼ 68
P
85% (73.9e91.9) 81.6% (75.2e86.7) 88.2% (78.3e93.9) 0.44 90.7% (78.4e96.3) 88.1% (81.3e92.7) 94.4% (84.9e98.1) 0.42 70.6% (46.9e86.7) 64.6% (50.4e76.6) 64.3% (38.8e83.7) 0.90 25.0% (10.2e49.5) 32.6% (20.9e47.0) 25% (8.9e53.2) 0.79 11.4% (5.0e24.0)
13.3% (8.5e20.2)
8.9% (3.9e19.3)
0.83
Table 4 Accuracy of macroscopic description according to gender of the patient. Intraoperative assessment
Histological assessment Normal
Female Normal Appendicitis Male Normal Appendicitis Total
Appendicitis
Total
35 10
17 72
52 82
17 13 75
10 129 168
27 142 303
3.4. Analysis of macroscopic assessment in correlation to sex of the patient A total of 134 appendicectomies were performed on females and 169 cases were performed on males (see Table 4). Of the histologically positive appendixes, there was a higher rate of true positives identified by the surgeon in male patients (92.8%; 95%CI: 87.3e96.1%) compared with females (80.9%; 95%CI: 71.5e87.7%), P ¼ 0.007. The accuracy of intraoperative diagnosis of the appendicitis did not significantly differ between male and female patients (86.4% vs 79.9%, p ¼ 0.27). The negative appendicectomy rate in females was significantly higher than in males (33.6% (45/134) vs 17.8% (30/169) P ¼ 0.002). The false negative rate was significantly higher in females than in males (19.1% vs 7.2% respectively, P ¼ 0.007) and there was a higher false positive rate in males than in female (43.3% versus 22.2% respectively, P ¼ 0.05). Of the 17 female patients who had a false negative result, six (35%) had other findings documented intraoperatively: ovarian cysts (n ¼ 4), retrograde menstruation (n ¼ 1) and endometriosis (n ¼ 1). 4. Discussion We found that the overall accuracy rate for the correct correlation of macroscopic assessment of the appendix to the histopathology was 83.5% which is comparable with previous studies with
Table 2 Accuracy of macroscopic assessment according to grade of operating surgeon. Intraoperative assessment
Histological assessment Normal
Junior trainees (N ¼ 60) Normal Appendicitis Senior trainees (N ¼ 174) Normal Appendicitis Consultant level (N ¼ 68) Normal Appendicitis Total
Appendicitis
Total
12 4
5 39
17 43
31 15
17 111
48 126
9 3 74
5 51 228
14 54 302
reported accuracy rates of 82.4e87.3% [6,7,15] Our findings demonstrated that the correlation between the intraoperative macroscopic description of the appendix by the surgeon compared with histological reports does not appear to be related to surgical experience. This is consistent with a previous study, which evaluated mainly open appendicectomies and found that surgical experience made no significant difference [6]. In contrast, AlGhnaniem et al. observed that inexperienced laparoscopic surgeons were more likely to make an incorrect macroscopic diagnosis compared to attending surgeons, with a 21% versus a 6% inaccuracy rate [15]. Although not statistically significant, our findings demonstrated a lower accuracy rate amongst senior trainees compared to junior trainees. The reason for this is unclear and may due to the attendance of a consultant who was unscrubbed, but present in the operating room during the surgery performed by the junior trainees, and thus not reflected in documentation. Consistent with previous studies, the ability to identify appendicitis with clear signs of overt disease such as perforation or abscess formation was with 100% accuracy. Previous studies showed that synonymous terms used by surgeons in the operation report such as “congested” or “catarrhal”, only correlate with histopathological diagnosis in 80% [6,7]. Our study demonstrated a significantly higher negative appendicectomy rate in females (33.6%) than in males (17.8%). A recent Australian study of 4670 patients showed a higher rate of negative appendicectomies in females than males (31% vs 16.8% respectively) [22]. The higher rates of negative appendicectomies seen in the female population are likely due to the misdiagnosis of appendiceal disease in females, with a recent 10-year retrospective study demonstrating that gynaecological conditions involving the ovary were reported as the most common diagnosis mistaken for appendicitis in females [23]. Conversely, we found that 35% of the female cases who were incorrectly diagnosed intraoperatively as macroscopically normal also had gynaecological abnormalities observed during the operation reflecting the challenge of diagnosing appendicitis in women. It has been increasingly suggested that a diagnostic laparoscopy prior to performing an appendicectomy allows the surgeon to
Please cite this article in press as: H. Pham, et al., Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.02.019
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explore the abdomen and exclude or confirm other pathologies that mimic appendicitis. One study showed that, with use of diagnostic laparoscopy and other clinical diagnostic tools such CT and US, the rate of negative appendicectomies can be reduced particularly in women of childbearing age [24], and other studies have recommended that a macroscopically normal appendix should be left in situ, even when no other abnormality is found [5,14,25,26]. However the risk of an inaccurate intraoperative assessment is a concern. A study in the Netherlands found that 9% of patients represented with right lower quadrant pain after a macroscopically normal appendix was left in situ [14]. Teh et al. reported that of 41 patients who had laparoscopy alone, 13 patients continued to have symptoms and 2 eventually proceeded to a laparoscopic diagnosis [13]. They found that while laparoscopic assessment was observed to have a better positive predictive value, there was no significant reduction in overall inaccurate diagnosis intraoperatively, with a rate of 81% of accurately identifying a normal appendix [13]. This is consistent with our data suggesting the limited accuracy in the diagnosis of appendicitis intraoperatively. Our study demonstrates that the surgeon's intraoperative assessment of the appendix is not completely reliable and that even during laparoscopy, correctly identifying a normal looking appendix was not achieved in about two thirds of patients. One reason for this may be due to the inflammatory change confined to the mucosa. While our findings demonstrate a discrepancy between intraoperative diagnosis and histopathology, we are unable to comment on the safety of leaving a normal looking appendix in situ. Further research is warranted for evaluating long term outcomes of leaving a macroscopically normal appendix in situ. This study has several limitations loosely due to its retrospective nature. Firstly, it was only performed at a single tertiary teaching institution in NSW. In order to gain a more broad assessment of the diagnostic accuracy of surgical trainees, further evaluation could include other hospitals. It is important to note that intraoperative assessment of the appendix may be influenced by the clinical and radiological assessment of the patient prior to the operation. Preoperative imaging demonstrating or excluding appendicitis through CT and/or ultrasound can therefore lead to a biased assessment intraoperatively with potential skewed results. In our study, within those who had preoperative imaging, 42.3% (n ¼ 11/ 26) of the cases that were inaccurately diagnosed demonstrated a correlation between the radiological diagnosis and macroscopic assessment. This may reflect the possible influence of the known radiological findings on the intraoperative assessment of the appendix. A significant limitation of this study was that the data was underpowered with respect to detecting the effects of surgical experience on accuracy of diagnosis. This is likely due to the small sample size, indicating the need for larger multicentre and multistudy analysis. Due to the retrospective nature of the study, the data retrieved relied primarily on accurate documentation in the operation reports. Information not accurately recorded by the surgeon with a more senior operator involved in the operation not documented may reflect a recall bias, representing a potential shortcoming of the study. The surgical education and training (SET) level of the trainees were used in the study to define operator experience, only applicable to accredited trainees on the surgical program, representing a crude estimate of actual operative experience. Junior doctors not on a surgical training programme including senior resident medical officers were documented as junior trainees in this study regardless of postgraduate year. Surgical experience is also influenced by the number of appendicectomies performed by previously by each trainee, which was not assessed in this study. We found that the degree of surgical experience does not affect the accuracy of macroscopic assessment of appendiceal pathology.
We conclude that intraoperative assessment of appendicitis remains limited with observed discrepancy between macroscopic appearance and histopathology. The practice of appendicectomy for suspected appendicitis should not be altered due to the risk of missed appendicitis, with subsequent chronic appendicitis and reoperation, thus we would recommend that the appendicectomy be performed if clinically indicated despite its intraoperative appearance. Ethical approval Ethics approval has been approved by the Human Research Ethics Committee. I am awaiting the reference number to be emailed to me by my supervisor who is currently away. Sources of funding None. Author contribution H Pham: Study design, data collection, analysis, writing of the manuscript. M Devadas: Study design, data collection and writing of the manuscript. J Howle: Study design, writing and final editing. Conflicts of interest None. Guarantor Helen Pham. References [1] S.J. Nixon, A. Rajasekar, Laparoscopic Appendicectomy, in: General Surgical Operations, Churchill Livingstone, London, 2000. [2] V.A. Pittman-Waller, J.G. Myers, R.M. Stewart, D.L. Dent, C.P. Page, G.A. Gray, et al., Appendicitis: why so complicated? Analysis of 5755 consecutive appendectomies, Am. Surg. 66 (6) (2000) 548e554. [3] AIHW, Australian Hospital Statistics 2010e11, 2012. http://www.aihw.gov.au/ publication-detail/?id¼10737421633&tab¼2. [4] R.J. Baigrie, T.C. Dehn, S.M. Fowler, D.C. Dunn, Analysis of 8651 appendicectomies in England and Wales during 1992, Br. J. Surg. 82 (7) (1995) 933. [5] M. Kraemer, C. Ohmann, R. Leppert, Q. Yang, Macroscopic assessment of the appendix at diagnostic laparoscopy is reliable, Surg. Endosc. 14 (7) (2000) 625e633. [6] J.K. Roberts, M. Behravesh, J. Dmitrewski, Macroscopic findings at appendicectomy are unreliable: implications for laparoscopy and malignant conditions of the appendix, Int. J. Surg. Pathol. 16 (4) (2008) 386e390. [7] M.W. Jones, A.G. Paterson, The correlation between gross appearance of the appendix at appendicectomy and histological examination, Ann. R. Coll. Surg. Engl. 70 (2) (1988) 93e94. [8] W.Y. Lau, S.T. Fan, T.F. Yiu, K.W. Chu, H.C. Suen, K.K. Wong, The clinical significance of routine histopathologic study of the resected appendix and safety of appendiceal inversion, Surg. Gynecol. Obstet. 162 (3) (1986) 256e258. [9] B. Grunewald, J. Keating, Should the ‘normal’ appendix be removed at operation for appendicitis? J. R. Coll. Surg. Edinb. 38 (3) (1993) 158e160. [10] M. Chiarugi, P. Buccianti, L. Decanini, R. Balestri, L. Lorenzetti, M. Franceschi, et al., “What you see is not what you get”. A plea to remove a ‘normal’ appendix during diagnostic laparoscopy, Acta Chir. Belg. 101 (5) (2001) 243e245. [11] K.L. Greason, J.F. Rappold, M.A. Liberman, Incidental laparoscopic appendectomy for acute right lower quadrant abdominal pain. Its time has come, Surg. Endosc. 12 (3) (1998) 223e225. [12] A. Hussain, H. Mahmood, T. Singhal, S. Balakrishnan, S. El-Hasani, What is positive appendicitis? A new answer to an old question. Clinical, macroscopical and microscopical findings in 200 consecutive appendectomies, Singap. Med. J. 50 (12) (2009) 1145e1149. [13] S.H. Teh, S. O'Ceallaigh, J.G. McKeon, M.K. O'Donohoe, W.A. Tanner, F.B. Keane, Should an appendix that looks ‘normal’ be removed at diagnostic laparoscopy for acute right iliac fossa pain? Eur. J. Surg. 166 (5) (2000) 388e389.
Please cite this article in press as: H. Pham, et al., Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.02.019
Q3
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H. Pham et al. / International Journal of Surgery xxx (2015) 1e5 [14] W.T. van den Broek, A.B. Bijnen, P. de Ruiter, D.J. Gouma, A normal appendix found during diagnostic laparoscopy should not be removed, Br. J. Surg. 88 (2) (2001) 251e254. [15] R. Al-Ghnaniem, H.M. Kocher, A.G. Patel, Prediction of inflammation of the appendix at open and laparoscopic appendicectomy: findings and consequences, Eur. J. Surg. 168 (1) (2002) 4e7. [16] A.W. Phillips, A.E. Jones, K. Sargen, Should the macroscopically normal appendix be removed during laparoscopy for acute right iliac fossa pain when no other explanatory pathology is found? Surg. Laparosc. Endosc. Percutan Tech. 19 (5) (2009) 392e394. [17] B. Navez, A. Therasse, Should every patient undergoing laparoscopy for clinical diagnosis of appendicitis have an appendicectomy? Acta Chir. Belg. 103 (1) (2003) 87e89. [18] R.E. Andersson, A. Hugander, A.J. Thulin, Diagnostic accuracy and perforation rate in appendicitis: association with age and sex of the patient and with appendicectomy rate, Eur. J. Surg. 158 (1) (1992) 37e41. [19] L. Graff, J. Russell, J. Seashore, J. Tate, A. Elwell, M. Prete, et al., False-negative and false-positive errors in abdominal pain evaluation: failure to diagnose acute appendicitis and unnecessary surgery, Acad. Emerg. Med. 7 (11) (2000) 1244e1255. [20] M.D. Tata, R. Singh, A.A. Bakar, P. Selvindoss, P K, R. Gurunathan, Laparoscopic
[21]
[22]
[23]
[24]
[25] [26]
5
appendicectomy: the ideal procedure for laparoscopic skill training for surgical registrars, Asian J. Surg. 31 (2) (2008) 55e58. Q4 V. Advani, S. Ahad, C. Gonczy, S. Markwell, I. Hassan, Does resident involvement effect surgical times and complication rates during laparoscopic appendectomy for uncomplicated appendicitis? An analysis of 16,849 cases from the ACS-NSQIP, Am. J. Surg. 203 (3) (2012), 347e51; discussion 51e2. M.D. Chandrasegaram, L.A. Rothwell, E.I. An, R.J. Miller, Pathologies of the appendix: a 10-year review of 4670 appendicectomy specimens, ANZ J. Surg. 82 (11) (2012) 844e847. S.A. Seetahal, O.B. Bolorunduro, T.C. Sookdeo, T.A. Oyetunji, W.R. Greene, W. Frederick, et al., Negative appendectomy: a 10-year review of a nationally representative sample, Am. J. Surg. 201 (4) (2011) 433e437. C.L. Bijnen, W.T. van den Broek, A.B. Bijnen, P. de Ruiter, D.J. Gouma, Implications of removing a normal appendix, Dig. Surg. 20 (3) (2003), 215e9; discussion 20e1. J.B. Olsen, C.J. Myren, P.E. Haahr, Randomized study of the value of laparoscopy before appendicectomy, Br. J. Surg. 80 (7) (1993) 922e923. A. Thorell, S. Grondal, K. Schedvins, G. Wallin, Value of diagnostic laparoscopy in fertile women with suspected appendicitis, Eur. J. Surg. 165 (8) (1999) 751e754.
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Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Original research
Q6
Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study
Q5
Helen Pham*, Michael Devadas, Julie Howle Department of Surgery, Westmead Hospital, Corner of Darcy and Hawkesbury Rd, Westmead, NSW, Australia
h i g h l i g h t s
Q2
We examined the accuracy of intraoperative macroscopic assessment of the appendix in correlation to the experience of the operator and the gender of the patient. The diagnostic accuracy amongst junior trainees, senior trainees and consultants did not differ with accuracy rates of 85%, 81.6% and 88.2% respectively. The false negative rate was higher in females than in males (19.1% versus 7.2%; P ¼ 0.007). The false positive rate was higher in males than in female patients (43.3% versus 22.2%; P ¼ 0.05). We recommend that an appendicectomy be performed when clinically indicated regardless of macroscopic appearance.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 11 January 2015 Received in revised form 13 February 2015 Accepted 24 February 2015 Available online xxx
Background: We aimed to determine whether intraoperative macroscopic assessment of the appendix improves with surgical experience and whether the accuracy of the intraoperative assessment of the appendix is different in respect to sex of the patient. Methods: Medical records of all appendicectomies performed during an 18-month period (2011e2012) at Westmead Hospital, Australia were reviewed. Accuracy of intraoperative macroscopic description correlating to histopathology was compared between groups based on the training level of the surgeon. Results: Correlation between the intraoperative diagnosis and final histopathology result was 83.5% of the 303 cases. The diagnostic accuracy amongst junior trainees, senior trainees and consultants did not differ with accuracy rates of 85%, 81.6% and 88.2% respectively, (P ¼ 0.44). The false negative rate was higher in females than in males (19.1% versus 7.2%; P ¼ 0.007). Conclusions: Our findings demonstrated that operator experience does not affect the accuracy of the intraoperative assessment of appendixes. We recommend that an appendicectomy be performed when clinically indicated regardless of macroscopic appearance. © 2015 Published by Elsevier Ltd on behalf of Surgical Associates Ltd.
Keywords: Appendectomy Histopathology Appendicitis Training Laparoscopic
1. Introduction Appendicectomy for acute appendicitis is one of the most common surgical procedures performed in hospitals [1,2], with approximately 22,000 operations undertaken in Australia in 2010e2011 [3]. However, a reported 15e30% of normal appendixes are removed, suggesting inaccuracy of intraoperative assessment of the appendix [4,5]. There is concern existing about the ability of surgeon to reliably detect abnormal pathological findings of the appendix intraoperatively [6e8] with current literature reporting
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* Corresponding author. 56 Simpson Rd, Bonnyrigg Heights, NSW 2177, Australia. E-mail address: [email protected] (H. Pham).
negative predictive value between 54.4% [6] and 74% [9] in open appendicectomy, and 41% [10] and 97% [11] in laparoscopic appendicectomy, questioning the ability of surgeons to adequately distinguish a normal appendix from an inflamed appendix. The question of whether or not to leave a normal looking appendix in place, has been widely disputed and a consensus has yet to be reached with some advocating for the removal of the appendix due to the potential of missed appendicitis [6,12], and others suggesting it is safe to leave in in situ [13,14]. Some authors advocate the removal of a normal looking appendix only in the context that there is no other existing explanatory pathology [15e17]. Previous studies have highlighted the low diagnostic accuracy rates in women (60%) when compared to males [18], which may be due to conditions that mimic appendicitis such as gynaecological
http://dx.doi.org/10.1016/j.ijsu.2015.02.019 1743-9191/© 2015 Published by Elsevier Ltd on behalf of Surgical Associates Ltd.
Please cite this article in press as: H. Pham, et al., Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.02.019
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abnormalities resulting in a higher incidence of false positive diagnosis in the female population [19]. High false negative rates of 18.6% reported in a retrospective study also raises concerns of the increased risks of perforations and abscess formation if the macroscopically normal but histological abnormal appendix was left in situ [19]. Trainee surgeons play an integral role in the assessment and management of patients especially in large teaching hospitals under the supervision of experienced consultants. Laparoscopic appendicectomy has been generally considered a safe procedure for trainees with a study finding no difference in operative time and morbidity compared to qualified surgeons [20], whereas another study has reported an increase surgical operative times and complications when surgical trainees are involved [21]. However the ability of surgical trainees to make an accurate intraoperative diagnosis of appendicitis has not been fully evaluated. We aimed to assess accuracy of the intraoperative assessment of the appendix in correlation to the histopathological diagnosis, and its association to surgeon experience and sex of the patient. 2. Methods Following ethics approval, we conducted a retrospective chart review of all patients who underwent an appendicectomy between January 1, 2011 and July 2012, at Westmead Hospital, a tertiary referral hospital in Sydney, Australia. Data was collected from patient medical records, operative theatre reports and histopathology reports. Patient demographics including sex, operative findings, operator details and final histological diagnosis were retrieved. Operative factors such as approach (open or laparoscopic) were noted. Patients who underwent incidental appendicectomy for reasons other than suspected appendicitis were excluded. One case where the operator was not documented on the report was excluded from the analysis. The intraoperative macroscopic description was retrieved from the operation report. For comparison between intraoperative and histopathological findings, the histological diagnosis was taken to be the gold standard. The extent of macroscopic disease documented by the surgeon was identified and categorised into the grades of appendicitis: inflamed, suppurative, gangrenous, and complicated (perforated/abscess) formation. Six cases described as being phlegmonous appendicitis were included within the category of complicated appendicitis. Findings documented by the surgeon or the pathologist as faecolith or fibrosis obliterans were not recorded as acute appendicitis. Additional operative findings documented by the surgeon were noted. The surgical level of the operating surgeon and assistant were reviewed, with the more senior surgeon who was scrubbed in identified as the main operator for this study. The Surgical Education & Training (SET) program is a recognised accredited five year surgical training program in Australia. Surgical Education & Training (SET) level was chosen as the standard of comparison was obtained for the surgeons involved during the time of the study. The grade of the operating surgeon was categorised as (1) Junior surgical trainees (senior Resident Medical Officer, SET 1 and 2); (2) Senior surgical trainees (SET 3, 4, and 5); and (3) Consultant level (Fellows and consultants). Senior resident medical officers included in the study were operators that were not affiliated with an accredited SET position and included unaccredited trainees. Based on these groupings, the accuracy of intraoperative macroscopic assessment of the appendix in correlation to histopathology was compared. Statistical analysis of comparison the groups and its statistical significance was performed using Statistical Package of Social Sciences version 21. The chi square test was used and probabilities less
than 0.05 were considered significant. A sample size estimate was calculated and required 555 patients in each group to reach a power of 0.8 and significance level of 0.05. However due to the retrospective nature of the study, we relied on available medical records to obtain our data. With our sample size, post hoc power analysis demonstrated that our study to have insufficient power to detect a significant difference between the three groups of surgical training levels (power ¼ 0.27) and between the male and female groups (power 0.38). 3. Results 3.1. Demographics Over the study period 303 patients underwent appendicectomy for suspected appendicitis, including 134 females and 169 males. The mean age of the study population was 30.9 years (age range 15e86 and 16e82 in females and males respectively). Appendicectomy was performed laparoscopically in the majority of cases (94.7%, 287/303), and an open approach was used in 16 patients, including nine cases which were converted from laparoscopy. 3.2. Analysis of intraoperative macroscopic assessment The macroscopic description of appendicitis documented by the surgeon was termed as inflamed/inflammation in 44.6% of cases (n ¼ 135), suppurative in 14.2% of cases (n ¼ 43), gangrenous in 2.8% (n ¼ 9) of cases and complicated appendicitis reported as perforation or abscess in 12.2% of cases (n ¼ 37). The overall accuracy of intraoperative macroscopic assessment of the appendix was 83.5% (253/303) with a positive predictive value (PPV) of 89.7% (201/224). The accuracy rate was 100% when findings of gangrenous appendicitis or complicated appendicitis such as perforation or abscess were described. When suppurative appendicitis was observed there was a 95.3% (41/43) correlation to a positive histopathology and when inflammation alone was observed, the PPV was 84.4% (114/135). The overall negative appendicectomy rate was 24.8% (75/303). Twenty three (10.3%) out of 224 patients who were deemed positive intraoperatively were found to have a normal appendix on microscopic examination. Seventy-nine cases were reported as being macroscopically normal with 27 (34.2%) demonstrating signs of appendicitis on histopathology. Preoperative imaging through CT and/or US was performed on 150 cases with radiological diagnosis of appendicitis in 90 of the cases (see Table 1). Of the 90 patients with preoperative imaging suggesting appendicitis, 2 cases were incorrectly diagnosed intraoperatively to have macroscopic signs of appendicitis. Conversely, of the 60 cases reported normal on preoperative imaging, 9 cases were described intraoperatively to be macroscopically normal, but
Table 1 Macroscopic assessment of the appendix in cases with preoperative radiological assessment (N ¼ 150). Histological assessment Appendicitis Radiological positive (n ¼ 90) Macroscopic positive Macroscopic negative Radiological negative (n ¼ 60) Macroscopic positive Macroscopic negative Total
Normal
Total
69 7
2 12
71 19
21 9 106
7 23 44
28 32 150
Please cite this article in press as: H. Pham, et al., Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.02.019
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histopathology demonstrated appendicitis.
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Table 3 Effect of surgical experience on the intraoperative diagnosis of appendicitis.
3.3. Analysis of macroscopic assessment in correlation to surgical experience
Intraoperative Grade of operating surgeon assessment Junior trainees Senior trainees N ¼ 60 N ¼ 174
The appendicectomies were performed by junior trainees in 60 cases; senior trainees in 174 cases; and consultants in 68 cases, (see Table 2). There was no significant difference in the accuracy of the intraoperative assessment of the appendix when comparing the experience of the operating surgeon, P ¼ 0.44 (see Table 3). Our results demonstrate that junior trainees, senior trainees and consultants obtained accuracy rates of 85% (95%CI: 73.9e91.9%), 81.6% (95%CI: 75.2e86.7%) and 88.2% (95%CI: 78.5e93.9%) respectively. The PPV was similar between all surgical training level groups with junior trainees accurately predicting appendicitis in 90.7% of cases (39/43; 95%CI: 78.4e96.3%). Although not statistically significant, the PPV was lower in senior trainees in 88.1% of cases (111/ 126; 95%CI: 81.3e92.7%) and higher in consultants with a PPV of 94.4% of cases (51/54; 95%CI: 84.9e98.1%), (P ¼ 0.42). The ability of correctly identifying a normal looking appendix was low across all groups with NPV of 70.6% in junior trainees, 64.6% in senior trainees and 64.3% in consultants (12/17, 31/48 and 9/14 respectively, p ¼ 0.9).
Accuracy % (95%CI) PPV % (95%CI) NPV % (95%CI) False positive rate (95%CI) False negative rate (95%CI)
Consultant level N ¼ 68
P
85% (73.9e91.9) 81.6% (75.2e86.7) 88.2% (78.3e93.9) 0.44 90.7% (78.4e96.3) 88.1% (81.3e92.7) 94.4% (84.9e98.1) 0.42 70.6% (46.9e86.7) 64.6% (50.4e76.6) 64.3% (38.8e83.7) 0.90 25.0% (10.2e49.5) 32.6% (20.9e47.0) 25% (8.9e53.2) 0.79 11.4% (5.0e24.0)
13.3% (8.5e20.2)
8.9% (3.9e19.3)
0.83
Table 4 Accuracy of macroscopic description according to gender of the patient. Intraoperative assessment
Histological assessment Normal
Female Normal Appendicitis Male Normal Appendicitis Total
Appendicitis
Total
35 10
17 72
52 82
17 13 75
10 129 168
27 142 303
3.4. Analysis of macroscopic assessment in correlation to sex of the patient A total of 134 appendicectomies were performed on females and 169 cases were performed on males (see Table 4). Of the histologically positive appendixes, there was a higher rate of true positives identified by the surgeon in male patients (92.8%; 95%CI: 87.3e96.1%) compared with females (80.9%; 95%CI: 71.5e87.7%), P ¼ 0.007. The accuracy of intraoperative diagnosis of the appendicitis did not significantly differ between male and female patients (86.4% vs 79.9%, p ¼ 0.27). The negative appendicectomy rate in females was significantly higher than in males (33.6% (45/134) vs 17.8% (30/169) P ¼ 0.002). The false negative rate was significantly higher in females than in males (19.1% vs 7.2% respectively, P ¼ 0.007) and there was a higher false positive rate in males than in female (43.3% versus 22.2% respectively, P ¼ 0.05). Of the 17 female patients who had a false negative result, six (35%) had other findings documented intraoperatively: ovarian cysts (n ¼ 4), retrograde menstruation (n ¼ 1) and endometriosis (n ¼ 1). 4. Discussion We found that the overall accuracy rate for the correct correlation of macroscopic assessment of the appendix to the histopathology was 83.5% which is comparable with previous studies with
Table 2 Accuracy of macroscopic assessment according to grade of operating surgeon. Intraoperative assessment
Histological assessment Normal
Junior trainees (N ¼ 60) Normal Appendicitis Senior trainees (N ¼ 174) Normal Appendicitis Consultant level (N ¼ 68) Normal Appendicitis Total
Appendicitis
Total
12 4
5 39
17 43
31 15
17 111
48 126
9 3 74
5 51 228
14 54 302
reported accuracy rates of 82.4e87.3% [6,7,15] Our findings demonstrated that the correlation between the intraoperative macroscopic description of the appendix by the surgeon compared with histological reports does not appear to be related to surgical experience. This is consistent with a previous study, which evaluated mainly open appendicectomies and found that surgical experience made no significant difference [6]. In contrast, AlGhnaniem et al. observed that inexperienced laparoscopic surgeons were more likely to make an incorrect macroscopic diagnosis compared to attending surgeons, with a 21% versus a 6% inaccuracy rate [15]. Although not statistically significant, our findings demonstrated a lower accuracy rate amongst senior trainees compared to junior trainees. The reason for this is unclear and may due to the attendance of a consultant who was unscrubbed, but present in the operating room during the surgery performed by the junior trainees, and thus not reflected in documentation. Consistent with previous studies, the ability to identify appendicitis with clear signs of overt disease such as perforation or abscess formation was with 100% accuracy. Previous studies showed that synonymous terms used by surgeons in the operation report such as “congested” or “catarrhal”, only correlate with histopathological diagnosis in 80% [6,7]. Our study demonstrated a significantly higher negative appendicectomy rate in females (33.6%) than in males (17.8%). A recent Australian study of 4670 patients showed a higher rate of negative appendicectomies in females than males (31% vs 16.8% respectively) [22]. The higher rates of negative appendicectomies seen in the female population are likely due to the misdiagnosis of appendiceal disease in females, with a recent 10-year retrospective study demonstrating that gynaecological conditions involving the ovary were reported as the most common diagnosis mistaken for appendicitis in females [23]. Conversely, we found that 35% of the female cases who were incorrectly diagnosed intraoperatively as macroscopically normal also had gynaecological abnormalities observed during the operation reflecting the challenge of diagnosing appendicitis in women. It has been increasingly suggested that a diagnostic laparoscopy prior to performing an appendicectomy allows the surgeon to
Please cite this article in press as: H. Pham, et al., Effect of surgical experience on the macroscopic diagnosis of appendicitis: A retrospective cohort study, International Journal of Surgery (2015), http://dx.doi.org/10.1016/j.ijsu.2015.02.019
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explore the abdomen and exclude or confirm other pathologies that mimic appendicitis. One study showed that, with use of diagnostic laparoscopy and other clinical diagnostic tools such CT and US, the rate of negative appendicectomies can be reduced particularly in women of childbearing age [24], and other studies have recommended that a macroscopically normal appendix should be left in situ, even when no other abnormality is found [5,14,25,26]. However the risk of an inaccurate intraoperative assessment is a concern. A study in the Netherlands found that 9% of patients represented with right lower quadrant pain after a macroscopically normal appendix was left in situ [14]. Teh et al. reported that of 41 patients who had laparoscopy alone, 13 patients continued to have symptoms and 2 eventually proceeded to a laparoscopic diagnosis [13]. They found that while laparoscopic assessment was observed to have a better positive predictive value, there was no significant reduction in overall inaccurate diagnosis intraoperatively, with a rate of 81% of accurately identifying a normal appendix [13]. This is consistent with our data suggesting the limited accuracy in the diagnosis of appendicitis intraoperatively. Our study demonstrates that the surgeon's intraoperative assessment of the appendix is not completely reliable and that even during laparoscopy, correctly identifying a normal looking appendix was not achieved in about two thirds of patients. One reason for this may be due to the inflammatory change confined to the mucosa. While our findings demonstrate a discrepancy between intraoperative diagnosis and histopathology, we are unable to comment on the safety of leaving a normal looking appendix in situ. Further research is warranted for evaluating long term outcomes of leaving a macroscopically normal appendix in situ. This study has several limitations loosely due to its retrospective nature. Firstly, it was only performed at a single tertiary teaching institution in NSW. In order to gain a more broad assessment of the diagnostic accuracy of surgical trainees, further evaluation could include other hospitals. It is important to note that intraoperative assessment of the appendix may be influenced by the clinical and radiological assessment of the patient prior to the operation. Preoperative imaging demonstrating or excluding appendicitis through CT and/or ultrasound can therefore lead to a biased assessment intraoperatively with potential skewed results. In our study, within those who had preoperative imaging, 42.3% (n ¼ 11/ 26) of the cases that were inaccurately diagnosed demonstrated a correlation between the radiological diagnosis and macroscopic assessment. This may reflect the possible influence of the known radiological findings on the intraoperative assessment of the appendix. A significant limitation of this study was that the data was underpowered with respect to detecting the effects of surgical experience on accuracy of diagnosis. This is likely due to the small sample size, indicating the need for larger multicentre and multistudy analysis. Due to the retrospective nature of the study, the data retrieved relied primarily on accurate documentation in the operation reports. Information not accurately recorded by the surgeon with a more senior operator involved in the operation not documented may reflect a recall bias, representing a potential shortcoming of the study. The surgical education and training (SET) level of the trainees were used in the study to define operator experience, only applicable to accredited trainees on the surgical program, representing a crude estimate of actual operative experience. Junior doctors not on a surgical training programme including senior resident medical officers were documented as junior trainees in this study regardless of postgraduate year. Surgical experience is also influenced by the number of appendicectomies performed by previously by each trainee, which was not assessed in this study. We found that the degree of surgical experience does not affect the accuracy of macroscopic assessment of appendiceal pathology.
We conclude that intraoperative assessment of appendicitis remains limited with observed discrepancy between macroscopic appearance and histopathology. The practice of appendicectomy for suspected appendicitis should not be altered due to the risk of missed appendicitis, with subsequent chronic appendicitis and reoperation, thus we would recommend that the appendicectomy be performed if clinically indicated despite its intraoperative appearance. Ethical approval Ethics approval has been approved by the Human Research Ethics Committee. I am awaiting the reference number to be emailed to me by my supervisor who is currently away. Sources of funding None. Author contribution H Pham: Study design, data collection, analysis, writing of the manuscript. M Devadas: Study design, data collection and writing of the manuscript. J Howle: Study design, writing and final editing. Conflicts of interest None. Guarantor Helen Pham. References [1] S.J. Nixon, A. Rajasekar, Laparoscopic Appendicectomy, in: General Surgical Operations, Churchill Livingstone, London, 2000. [2] V.A. Pittman-Waller, J.G. Myers, R.M. Stewart, D.L. Dent, C.P. Page, G.A. Gray, et al., Appendicitis: why so complicated? Analysis of 5755 consecutive appendectomies, Am. Surg. 66 (6) (2000) 548e554. [3] AIHW, Australian Hospital Statistics 2010e11, 2012. http://www.aihw.gov.au/ publication-detail/?id¼10737421633&tab¼2. [4] R.J. Baigrie, T.C. Dehn, S.M. Fowler, D.C. Dunn, Analysis of 8651 appendicectomies in England and Wales during 1992, Br. J. Surg. 82 (7) (1995) 933. [5] M. Kraemer, C. Ohmann, R. Leppert, Q. Yang, Macroscopic assessment of the appendix at diagnostic laparoscopy is reliable, Surg. Endosc. 14 (7) (2000) 625e633. [6] J.K. Roberts, M. Behravesh, J. Dmitrewski, Macroscopic findings at appendicectomy are unreliable: implications for laparoscopy and malignant conditions of the appendix, Int. J. Surg. Pathol. 16 (4) (2008) 386e390. [7] M.W. Jones, A.G. Paterson, The correlation between gross appearance of the appendix at appendicectomy and histological examination, Ann. R. Coll. Surg. Engl. 70 (2) (1988) 93e94. [8] W.Y. Lau, S.T. Fan, T.F. Yiu, K.W. Chu, H.C. Suen, K.K. Wong, The clinical significance of routine histopathologic study of the resected appendix and safety of appendiceal inversion, Surg. Gynecol. Obstet. 162 (3) (1986) 256e258. [9] B. Grunewald, J. Keating, Should the ‘normal’ appendix be removed at operation for appendicitis? J. R. Coll. Surg. Edinb. 38 (3) (1993) 158e160. [10] M. Chiarugi, P. Buccianti, L. Decanini, R. Balestri, L. Lorenzetti, M. Franceschi, et al., “What you see is not what you get”. A plea to remove a ‘normal’ appendix during diagnostic laparoscopy, Acta Chir. Belg. 101 (5) (2001) 243e245. [11] K.L. Greason, J.F. Rappold, M.A. Liberman, Incidental laparoscopic appendectomy for acute right lower quadrant abdominal pain. Its time has come, Surg. Endosc. 12 (3) (1998) 223e225. [12] A. Hussain, H. Mahmood, T. Singhal, S. Balakrishnan, S. El-Hasani, What is positive appendicitis? A new answer to an old question. Clinical, macroscopical and microscopical findings in 200 consecutive appendectomies, Singap. Med. J. 50 (12) (2009) 1145e1149. [13] S.H. Teh, S. O'Ceallaigh, J.G. McKeon, M.K. O'Donohoe, W.A. Tanner, F.B. Keane, Should an appendix that looks ‘normal’ be removed at diagnostic laparoscopy for acute right iliac fossa pain? Eur. J. Surg. 166 (5) (2000) 388e389.
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