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Prospective comparative assessment of ultrasonography and laparoscopy for contralateral patent processus vaginalis in inguinal hernia presented in the first year of life

Shehata, Sherif M.a,c; Ebeid, AbdelMotaleb E.a; khalifa, Osama M.c; Noor, Fayza M.d; Noomaan, AbdelMoneim A.b

doi: 10.1097/01.XPS.0000422614.15188.b5
ORIGINAL ARTICLES
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Background and purpose Contralateral inguinal exploration in children with unilateral inguinal hernia is still a controversial topic. The aim of this study was to present an evidence-based justification for contralateral inguinal exploration in our population after comparing the results of ultrasonography (US) and laparoscopy.

Methods Over a period of 3 years, 246 patients (207 boys and 39 girls) with unilateral inguinal hernia who were presented in the first year of life underwent an US using a 10 MHz linear transducer. Operative transinguinal contralateral laparoscopic exploration was carried out in all of them. The results were compared prospectively for the sensitivity and specificity of US and laparoscopy.

Results Our results showed a predominant left-side incidence in boys (50.7%) and a right-side incidence in girls (69.2%). With respect to prematurity, 24.6% of boys and 30.8% of patients with left-sided hernia were found to be premature. In all, 64.6% of patients were diagnosed in the neonatal period. We considered positive patent processus vaginalis (PPV) on US when types I–III according to the criteria of Toki and colleagues were reported. Positive PPV was confirmed by US in 30.5% of patients and by laparoscopy in 85.2%. Sonographic assessment of contralateral PPV gave a sensitivity of 91.7% and a specificity of 87.7%. Of the patients, the laparoscopic exploration yielded positive results in 35.8%. The cost of a negative laparoscopy is 50$ and that of a positive laparoscopy is 100$, which on second admission costs 500$.

Conclusion As in our community there is a high incidence of consanguinity, preoperative assessment of contralateral hernia should be considered in patients who are presented in the first year of life and in premature infants. In experienced hands US is a highly sensitive tool for the diagnosis of contralateral hernia. Laparoscopic exploration is safe, rapid, and a proven method for diagnosis, even in infants. We recommend laparoscopic exploration for all patients who are presented in the first year of life in order to avoid second admission, which can lower costs significantly.

Departments of aPediatric Surgery

bDiagnostic Imaging, Tanta University Hospital, Tanta, Egypt

Departments of cPediatric Surgery

dDiagnostic Imaging, Royal Commission Medical Center (RCMC), Yanbu, Kingdom of Saudi Arabia

Correspondence to AbdelMotaleb E. Ebeid, MD, Department of Pediatric Surgery, Faculty of Medicine, Tanta University, Elgish St. 31111 Tanta, Egypt Tel: +20 100 797 5755; fax: +002 040 221 8886; e-mails: ameffat@hotmail.com, ameffat@yahoo.com

Received July 28, 2012

Accepted October 15, 2012

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Introduction

Contralateral exploration of the groin has been a common practice among pediatric surgeons for nearly 50 years, based on the high incidence of patent processus vaginalis (PPV) on the contralateral side with the potential for subsequent development of hernia 1. However, the actual incidence of hernia among PPV patients is not definite. The patency rate of processus vaginalis is highest in infants, but there are few data on the subsequent risk of developing contralateral hernia in them 2. The incidence of contralateral PPV (CPPV) is higher among infants and premature boys 3. Despite this fact, contralateral inguinal exploration is a controversial subject in both infants and older children 4,5. Many methods have been used for the diagnosis of CPPV in unilateral cases of inguinal hernia to benefit from nonroutine operative exploration as it avoids unnecessary open exploration in 66% of infants and children undergoing inguinal hernia repair 6. Further, it also avoids exposure to general anesthesia for the second time, which is found favorable by parents as well 7. Ultrasonography (US) is one of the noninvasive techniques used to diagnose CPPV preoperatively using a 7.5 MHz superficial linear transducer either by detecting as a hydrocele owing to the inflow of physiologic ascites into a processus vaginalis on straining or classified according to Toki and colleagues criteria 8,9. Management of CPPV in a child with an inguinal hernia has been debated upon by surgeons for more than 50 years 7. With the advent of laparoscopy, many techniques have been utilized through both conventional and tangential laparoscopic approaches 10–12. Tangential laparoscopy is especially important in infants below 1 year of age 13. Evidence-based guidelines should be followed, even in the case of small or premature infants, which outline the standard of care to be adopted in a common pediatric surgical practice 14. Middle Eastern countries and many developing countries exhibit a high incidence of consanguinity. No studies were available from communities in which high consanguinity was prevalent.

The aim of this study was to present an evidence-based justification for CPPV exploration in our population after comparing the results of US and laparoscopy in a prospective manner and to prospectively evaluate laparoscopic exploration for CPPV in a cost-effective manner.

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Patients and methods

All patients with unilateral inguinal hernia who were presented in the first year of life over a period of 3 years (from January 2007 to December 2009) were included in the study. They comprised children presented at the Department of Pediatric Surgery, Royal Commission Medical Center, Yanbu, Kingdom of Saudi Arabia, from January 2007 to 30 June 2008, and at the Department of Pediatric Surgery, Tanta University Hospital, Egypt, from January 2008 to December 2009. The ethical research committee of both institutions approved the study design. All patients underwent preoperative US using a 10 MHz linear transducer. Preoperative sonographic results of patients with CPPV were classified according to the criteria of Toki et al.9, in which the findings, along with increases and decreases in intra-abdominal pressure, were categorized into six types as follows: type I – an intra-abdominal organ was observed in the inguinal canal; type II – the PPV was seen as a cyst at the internal ring of the inguinal canal; type III – the PPV was widened with increases in abdominal pressure (the length of the PPV was longer than 20 mm); type IV – the PPV contains moving fluid without PPV widening; type V – the PPV was widened with increases in abdominal pressure (the length is shorter than 20 mm); and type VI – other findings. Types I, II, and III were regarded as positive potential candidates for inguinal hernia. An operative tangential transinguinal contralateral laparoscopic exploration was performed in all patients. A 5 mm laparoscope was inserted and a 30° scope was passed tangentially after CO2 insufflation. Pressure ranging between 8 and 10 mmHg was found to be sufficient for the procedure with a flow rate of 0.5–1 l/min. The CPPV was inspected and evaluated. If the CPPV measured more than 1 cm in length and 5 mm in diameter on laparoscopic exploration, it was considered positive and was subjected to open herniotomy during the same session. If the diameter was less than 5 mm or the length of the CPPV was less than 1 cm, no intervention was performed as it was considered negative 3,7,11. Positive results were compared with respect to sensitivity and specificity of both US and laparoscopic findings.

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Results

A total 246 patients (207 boys and 39 girls) who were presented with unilateral inguinal hernia for the first time in the first year of life over a period of 3 years were included in the study. Left-sided presentation was reported to be predominant in boys (50.7%), whereas the right side predominated among girls (69.2%). With respect to prematurity, 24.6% of boys and 30.8% of patients with left-sided hernia were found to be premature. Among the premature boys, the ratio of left to right side incidence was reported as 2.65 : 1. A total of 159 patients (64.6%) were diagnosed during the neonatal period. Nine patients were presented to the emergency department with irreducibility, which was reduced manually and electively operated during the same admission.

Preoperative US revealed 75 patients with positive findings according to Toki’s classification. We considered positive PPV on US when types I–III, according to Toki and colleagues, were reported. Of the 75 positive patients, 15 were classified as type I, 33 as type II,and 27 as type III; 171 patients were considered negative. Figure 1 shows representations of the different types of Toki’s classification as seen among our patients.

Fig. 1

Fig. 1

Sonographic assessment of CPPV gave a sensitivity of 91.7% and a specificity of 87.7%. We obtained a false-negative rate of 24.1% with a positive predictive value of 75.9% and a false-positive rate of 3.8% with a negative predictive value of 96.2%. All patients underwent unilateral open herniotomy on an elective basis. Median operative age for all patients was 45 weeks, whereas that for the neonatally diagnosed patients was 13.3 weeks for full term and 21 weeks for premature babies; 54.3% of patients below 1 year of age were operated upon. Figure 2 shows the laparoscopic technique and the results of the laparoscopic exploration.

Fig. 2

Fig. 2

Of all the laparascopic explorations performed in the groups, 35.8% were positive. US confirmed PPV in 30.5% of patients, whereas laparoscopy confirmed it in 85.2%. Laparoscopic exploration had significantly higher sensitivity compared with US (100 and 91.7%, respectively). Patients with a positive result on laparoscopic exploration were managed by classic open herniotomy of the contralateral side during the same session. The added median cost of negative laparoscopy was 50$, whereas positive laparoscopy cost 100$, which on second admission had a median cost of 500$ per patient. After calculating the costs of both negative and positive laparoscopic exploration on avoiding a second admission, we could save 27 300$ during our study period, which was beneficial in terms of hospital resources.

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Discussion

The evaluation and management of CPPV in children presenting with a unilateral inguinal hernia has been a subject of debate for over 60 years 15. US is a noninvasive and accurate method for evaluating the presence of a CPPV 8. Although the efficacy of US against that of laparoscopy in the diagnosis of CPPV has been evaluated earlier, the age group tested in this study in the developing community has not been considered before. Intraoperative laparoscopy using a no-puncture technique through the opened hernia sac is useful for inspecting CPPV 10.

By combining all the published studies and using the technique of meta-analysis, intraoperative laparoscopy can be shown to be effective in diagnosing CPPV in children undergoing unilateral inguinal herniorrhaphy 16. Risk for metachronous manifestation of contralateral inguinal hernia in patients with unilateral inguinal hernia was shown to be significantly higher in boys with left-sided hernia, in premature children, and in patients with a positive family history 5,6,17. Left-sided presentation was reported to be 50.7% among boys and 30.8% among girls. This was in accordance with our findings of common left-sided presentation in premature boys, which we reported as 2.65 : 1 when compared with right-sided presentation. Patients with left-sided presentation of hernia have a statistically significantly higher incidence of metachronus inguinal hernia 14. In our study, 24.6% of boys and 30.8% of patients with left-sided hernia were premature. We had 207 boys among the 246 patients in our study with unilateral inguinal hernia for the first time in the first year of life. Schier et al. 18 reported an incidence of 23% for CPPV in patients with left-sided hernia and 22% among those with hernia on the right side; Eller Miranda and Duarte Lanna 19 reported a significantly higher incidence of contralateral hernia in patients with left-sided hernia, similar to our results. The overall median operative age was 45 weeks in our study, which was lower compared with that of others 18,20. Hata et al.8 reported that US with a 7.5 MHz linear transducer is a useful noninvasive tool for evaluating CPPV and had a specificity of 94.9%. In our study US had a sensitivity of 91.7%, which was lower than the sensitivity of 98.5% reported by Toki et al.9, who used a 10 MHz linear transducer. The lower sensitivity for US in our study is not significant and could be attributed to the lower median age of our patients as compared with similar studies 4,8,9,21 as US has been proven difficult to perform in very young infants.

We experienced 100% success in laparoscopic exploration even in thin sacs using the purse string suture around the cannula for insufflation when compared with a failure rate of 4.4% in passing the laparoscopic port in the study by Valusek et al.22. In all, 35.8% of all patients underwent a positive laparoscopic exploration. This supported the findings that laparoscopy can be used to reliably evaluate the contralateral inguinal region and is the best method to evaluate the presence of a CPPV as reported by Valusek et al.22 and Tamaddon et al. 23 as 39 and 38%, respectively. Tamaddon et al.23 reported that transinguinal laparoscopic evaluation using a 120° endoscope provided superior visualization and identification of CPPVs. However, we did not encounter problems on using a 30° endoscope in our study. The transinguinal tangential laparoscopic exploration proved to be effective in the diagnosis of CPPV without the need for a separate abdominal wall puncture and reduced the instances of missed PPV 13,22–24. In our study, patent PPV was US confirmed in 30.5% of patients by US and in 85.2% by laparoscopy. Laparoscopy had a sensitivity of 100%. In a study conducted by Miltenburg et al. 16 on 964 patients, the sensitivity of laparoscopy was 99.4% (95% confidence interval 97.87–99.91).These findings were in agreement with former reports 7,15,22, thus denoting the superiority of laparoscopy in the diagnosis of CPPV. Niyogi et al.25 reported the statistical advantages of laparoscopy in the diagnosis of CPPV. The technique of increasing and decreasing intra-abdominal pressure during both US and laparoscopy proved very valuable and we used this technique in all patients in our study. CPPV was predominantly prevalent among patients with left-sided hernia and in premature boys, as described by many studies 6,7,13,14. In the current study, laparoscopic exploration showed significantly higher sensitivity in diagnosing CPPV when compared with US. The predicted incidence of contralateral hernia in the study by Watanabe et al.26 was 11.2%. We reported a higher incidence of 35.8% for CPPV in our study. This could be attributed to the high incidence of consanguinity among families in our area and the Middle East. For this reason, laparoscopy can be effectively used to evaluate the contralateral inguinal region and is the best method to evaluate a CPPV 22. The laparoscopic exploration for CPPV is cost effective in terms of both cost to the patient and hospital resources as the positive exploration costs 100$. However, the minimum cost on second admission is 500$. Cost analysis comparing the time taken to perform laparoscopic exploration for CPPV with the cost saved by preventing future surgery for a contralateral inguinal hernia repair was calculated on the basis of Medicare reimbursement 27. We found that we had saved 27 300$ during our study period, which was in agreement with the results of Lee et al. 27 who calculated the total cost for a second operation to repair the contralateral inguinal hernia as 20 440$ per patient in the USA. The relatively high incidences of both CPPV and contralateral metachronous hernia development in children justify the use of laparoscopic evaluation as a routine 15. Contralateral exploration should therefore be reserved for high-risk patients in whom administration of anesthesia and surgery for the second time have to be avoided 17. Therefore, diagnostic intraoperative transinguinal laparoscopic evaluation of CPPV during pediatric inguinal hernia repair is a simple, accurate, fast, and effective method to assess the CPPV, improving decision making, reducing the number of negative explorations, and sparing the surgeon the embarrassment associated with the appearance of a metachronous hernia at a later date 24. Transinguinal laparoscopy offers a safe and effective means of evaluating the contralateral inguinal ring during ipsilateral hernia repair 27.

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Conclusion

Contralateral exploration should be reserved for high-risk patients in whom administration of anesthesia and surgery for the second time have to be avoided 17. In our community, preoperative assessment of contralateral hernia is justified and should be considered. It can be learned easily and should be a part of every pediatric surgeon’s practice. Laparoscopic contralateral groin exploration at the time of unilateral inguinal hernia repair is cost effective. With a 35.8% incidence of positive PPV patients, laparoscopic exploration is safe, rapid, and a sure method for diagnosis even in infants. We recommend the laparoscopic exploration of PPV in all patients who are presented in the first year of life so as to avoid a second admission, leading to a significant lowering of costs and avoiding a second exposure to general anesthesia, which may result in complications.

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Acknowledgements

Conflicts of interest

There are no conflicts of interest.

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