Open Preperitoneal Techniques versus Lichtenstein Repair for Inguinal Hernia
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
The objective of this review is to compare the efficacy of an open preperitoneal mesh repair via either posterior or anterior approach with the Lichtenstein technique. Efficacy will be considered the absence of chronic pain after at least 3 months of follow‐up. Chronic pain is defined as a reported VAS score >40 on a scale of 100.
Background
Description of the condition
The lifetime risk for requiring an inguinal hernia repair is 27% in men and 3% in women (Primatesta 1996). Data from the National Center for Health Statistics reveals that approximately 800,000 groin hernia repairs were completed in the United States in 2003 which results in enormous yearly health care expenditures. From a cost‐effectiveness perspective, however, time in the operating room, recovery room, and facility are the most important cost components (Rutkow 2003). Nowadays, as more than 90% of these operations are performed on an outpatient basis, this issue has already been addressed.
Other aspects concerning patient outcome, however, need still consideration and it remains necessary to improve the current standards regarding pain issues and quality of life, maintaining the low recurrence rates reported in the literature.
Description of the intervention
Since Bassini’s revolutionary technique (Bassini 1887) several open anterior, non‐prosthetic repairs have been developed of which the Shouldice and to a lesser extent McVay are the most commonly performed tissue repairs. The Shouldice clinic reports hernia recurrence rates of 0.13% for indirect and 0.31% for direct inguinal hernias (Shouldice 2003). However, these outstanding results have never been duplicated in non‐specialised centres (Butters 2007, Arlt 2002). McVay popularised the use of Cooper’s ligament in inguinal hernia repair, but resulting in recurrence rates ranging from 2% to 8.8% (Rutkow 1993; Panos 1992; Rutledge 1988). Moreover, an analysis of these elective non‐prosthetic repairs recorded in the Danish Hernia Database showed a recurrence rate of more than 8% after 7 1/2 year (Kehlet 2008). This major drawback led to the concept of tension‐free hernioplasty with mesh.
In the literature, it has been shown that mesh repair is superior to primary suture techniques (Grant 2002; EU Hernia Trialists Collaboration 2002; Scott 2001). These tension free techniques using mesh can be used both in open surgery and minimal access laparoscopy (McCormack 2003). In 1986 Irving Lichtenstein championed the open tension‐free approach in which the mesh is placed in front of the transversalis fascia (Lichtenstein 1986). This technique is reproducible and has reduced the hernia recurrence rates dramatically to 0.2% in some series (Shulman 1992). An other open repair technique is the use of a cone‐shaped mesh plug in the hernia defect, with or without an onlay mesh on the inguinal floor with outstanding recurrence rates of less than 1% (Wantz 1996; Rutkow 1995). The mesh can also be placed behind the transversalis fascia in the preperitoneal space. Nyhus introduced the open preperitoneal repair (Nyhus 1960), after whom René Stoppa first reported placing a giant prosthetic reinforcement of the visceral sac (GPRVS). This technique was mainly performed for recurrent and bilateral inguinal hernias (Stoppa 1969). Recurrence rates of 2% have been found in the literature (Gainant 2000; Mathonnet 1997). With only 5 recurrences in 808 hernia repairs Kugel described a preperitoneal mesh repair using a memory ring containing device (Kugel 1999). The Ugahary operation is similar considering surgical approach, but seems successful in more experienced hands only. An overall recurrence rate of 1.7% has been reported (Ugahary 2001).
Two commonly performed laparoscopic herniorrhaphies, transabdominal preperitoneal (TAPP) and the totally extraperitoneal (TEP), are modelled after the open preperitoneal operations described above. With 86 recurrences amongst 3138 laparoscopic repairs, there is no difference between laparoscopic and open mesh methods (McCormack 2003). When summarizing these data, current surgical techniques for inguinal hernia repair show similar recurrence rates and recurrence is therefore no longer the main issue discussed when considering improving the current standards for groin hernia repair. The opposite is true for patient (dis)comfort and quality of life.
How the intervention might work
To improve overall quality of life and especially postoperative chronic pain, an open preperitoneal repair might have several benefits (Voyles 2002) without the disadvantages of a laparoscopic procedure. Laparoscopic repair has been criticized because of its technical complexity, the need for experience, the possibility of serious complications, the need for general anaesthesia and the high cost (Kald 1997; Heikkinen 1998; McCormack 2005). The Lichtenstein technique is valid, but it requires extensive dissection in the inguinal canal and involves manipulation of at least one or two inguinal nerves (Nienhuijs 2007) with the need for extensive suturing and long term mesh related complications to the surrounding cord structures.
Why it is important to do this review
Post surgical chronic pain represents a major, largely unrecognised clinical problem (Kalliomäki 2009). After mesh‐based inguinal hernia repair, 11% of patients suffer chronic pain (Nienhuijs, Staal 2007). Incidences up to 54% have been reported (Poobalan 2003). Postoperative pain can be the consequence either of ongoing inflammation or, much more commonly, a manifestation of iatrogenic neuropathic pain due to injury to peripheral nerves (Kalliomäki 2009; Kehlet 2006). Consequently, there seems to be a need to not only decrease an extensive dissection in the inguinal canal with less manipulation of the inguinal nerves (Nienhuijs 2007), but also to minimize the interaction between the foreign material of the mesh and the spermatic cord as well as the nerves, by placing the mesh in an avascular space lacking major nervous structures. A last issue that might be addressed considering pain, is the influence of fixation of the mesh, i.e. both in laparoscopy and open surgery, fixation by tacks or sutures seems to be responsible for post surgical pain in most of the patients (Bär 2009). By placing the mesh in the preperitoneal space, a more physiological place for the mesh with intraabdominal forces on one side and the oblique muscles on the other, fixation seems less mandatory, although maybe not completely to be abandoned.
Objectives
The objective of this review is to compare the efficacy of an open preperitoneal mesh repair via either posterior or anterior approach with the Lichtenstein technique. Efficacy will be considered the absence of chronic pain after at least 3 months of follow‐up. Chronic pain is defined as a reported VAS score >40 on a scale of 100.
Methods
Criteria for considering studies for this review
Types of studies
We will consider any randomised controlled trials comparing any open preperitoneal mesh technique versus Lichtenstein repair for inclusion. We will not include any non‐randomised studies. We will also include studies that fulfil these criteria but comprise a comparison with one or more extra hernia repair techniques. The language of the trials will not be a criterion for exclusion.
Types of participants
Inguinal hernias are defined as protrusions of abdominal cavity contents through the inguinal canal.
All participants are adults. Only patients with elective repair of a primary, unilateral inguinal hernia are considered.
Exclusion criteria: strangulated inguinal hernia, bilateral inguinal hernia, recurrent inguinal hernia and age less than 18 years.
Types of interventions
‐Treatment group
All forms of open preperitoneal mesh repair:
1.Kugel patch technique
2.Ugahary technique
3.Read‐Stoppa repair
4.Polysoft repair
‐ Control group
1.Lichtenstein repair
2.Mesh Plug and Patch
We will also include studies that compare these interventions but include a comparison with one or more extra hernia repair techniques.
We will not differentiate between:
1. type of fixation of the mesh
2. the type of mesh
a.partially versus non‐absorbable
b.light versus heavy weight
c.large versus small pores
3.the anaesthesia technique used
4.postoperative instructions considering limitations in activity
In our opinion these variations in the intervention have no significant effect on the outcomes of interest of interest, as shown in the literature.
Types of outcome measures
Primary outcomes
Post surgical chronic pain represents a major, largely unrecognised clinical problem. Incidences after inguinal hernia repair up to 54% have been reported (Kalliomäki 2009; Nienhuijs, Staal 2007; Poobalan 2003).
Chronic postoperative pain measured using the Visual Analogue Scale (VAS) at three months or at a later time point during follow‐up. The cut off value for pain on the 100‐mm VAS will be 40.
Secondary outcomes
‐Acute pain, measured with the Visual Analogue Scale. We define acute pain as any pain score above 40 that persists during two weeks in the early postoperative phase.
‐Recurrence of the hernia: early (ie within 30 days) versus late (later than 30 days), defined as a clinically manifest bulge or a protrusion exacerbated by a Valsalva manoeuvre in the operated groin.
‐Other major postoperative complications (seroma and haematoma): early (ie within 30 days) and late (later than 30 days) as an indicator for technical difficulty.
Search methods for identification of studies
Electronic searches
We will perform the following search strategies:
‐MEDLINE (1966 to the present):
#1 randomized controlled trial [pt]
#2 controlled clinical trial [pt]
#3 prospective [tiab]
#4 randomized [tiab]
#5 inguinal hernia [tiab]
#6 herniorrhaphy [tiab]
#7 Lichtenstein [tiab]
#8 subaponeurotic [tiab]
#9 preperitoneal [tiab]
#10 Kugel [tiab]
#11 read‐rives [tiab]
#12 Stoppa [tiab]
#13 grid‐iron [tiab]
#14 mesh [tiab]
#15 prosthesis [tiab]
#16 memory ring [tiab]
#17 chronic pain [tiab]
#18 posterior [tiab]
#19 polysoft [tiab]
#20 Plug and patch [tiab]
#21 Onlay [tiab]
#22 Nyhus [tiab]
#23 Stoppa [tiab]
#24 Pain [tiab]
‐the Cochrane Central Register of Controlled Trials (CENTRAL), The Cochrane Library Issue 1, 2008
#1 MeSH descriptor Hernia, Inguinal explode all trees
#2 herniorrhaphy in All fields in all products
#3 Lichtenstein in All fields in all products
#4 subaponeurotic in All fields in all products
#5 preperitoneal in title, abstract or keywords
#6 Kugel in title, abstract or keywords
#7 read‐rives in title, abstract or keywords
#8 Stoppa in title, abstract or keywords
#9 grid‐iron in title, abstract or keywords
#10 mesh in title, abstract or keywords
#11 prosthesis in title, abstract or keywords
#12 memory ring in title, abstract or keywords
#13 chronic pain in title, abstract or keywords
#14 posterior in title, abstract or keywords
#15 polysoft in title, abstract or keywords
#16 plug and patch in title, abstract or keywords
#17 onlay in title, abstract or keywords
#18 Nyhus in title, abstract or keywords
#19 Stoppa in title, abstract or keywords
#20 Pain in title, abstract, or keywords
‐EMBASE (1980 to the present)
We will also search the references of the identified trials to identify further relevant trials
Searching other resources
www.controlled‐trials.com/mrct and www.clinicaltrials.gov will be searched for ongoing trials. The main investigators of any relevant ongoing trials will be contacted for further information and will be asked if they are aware of any other studies in order to find unpublished trials. We will also search for conference abstracts.
Data collection and analysis
Selection of studies
We will assess all the abstracts identified by the above search strategies. Two independent researchers (Mr Berrevoet, MD and Mr Willaert, MD) will exclude studies that do not meet the inclusion criteria. The former is knowledgeable in hernia surgery, the latter is not a content expert. We will try to obtain and assess the full publications of all possibly relevant abstracts for inclusion. We will resolve any differences in opinion through discussion with a third author (Mr Troisi, PhD). Review authors will not be blinded to the names of the study authors, their institutions, the journal of publication, or the results. We will also list the excluded studies with the reason for exclusion.
Data extraction and management
Two authors (Mr Willaert, MD and Mr Berrevoet, MD) will independently extract the data.
See Appendix 1: data collection form
The authors will discuss any disagreement with a third review author (Mr Troisi, PhD). If we have no agreement, we will report this in the review.
In the case of multiple reports of the same study, we will extract the data in separated data collection forms. We will look for missing information by contacting study authors
Assessment of risk of bias in included studies
All studies that will meet the selection criteria will be assessed for methodological quality.
Domain‐based evaluation will be done to assess the risk of bias in the included studies. We will assess risk of bias in the included studies as described in the Cochrane Handbook for Systematic Reviews of Interventions (Version 5.0.1) as follows:
1. selection bias: systematic differences between the groups that are compared
2. sequence generation
3. allocation concealment
4. blinding
5. incomplete outcome data
6. selective outcome reporting
7. other sources of bias
For each question‐based item, two authors (Mr Willaert, MD and Mr Berrevoet, MD) will describe what was reported to have happened in the study independently. Second they will make a judgement (Yes for low risk of bias, No for high risk of bias, or unclear) relating to the risk of bias.
Missing information about study design and conduct will be asked via open‐ended questions to trial authors.
Measures of treatment effect
‐Dichotomous outcomes:
We will study dichotomous pain outcomes as reported in the studies, that is: pain versus no pain; pain or use of pain medication, or both, versus no pain. As the summary statistic for our dichotomous primary outcome, we will use the risk ratio (RR) or odds ratio (OR).
‐Continuous outcomes:
When studies measure the same outcome in a variety of ways we will use the standardized mean difference (SMD) as a summary statistic.
‐Ordinal outcomes:
When outcome data will be provided on an ordinal scale (eg none, mild, moderate, severe, extremely severe pain), we will select a cut‐point and will convert these data into dichotomous form. One of the two sets of grouped categories is defined to be the event.
‐Time‐to‐event outcomes:
To measure early (less than 30 days) and late (more than 30 days) major postoperative complications.
Unit of analysis issues
The unit of randomisation in these trials is the individual patient. Because results from more than one time point for each study cannot be combined in a standard meta‐analysis without a unit‐of‐analysis error we will use specific definitions:
1. We define pain based on different periods of follow‐up.
‐ acute pain comes on quickly after the operation and can persist during two weeks in the early postoperative phase.
‐chronic pain is still present at three months or at a later time‐point in the follow‐up.
2. We classify postoperative complications and recurrences as early (less than 30 days) and late (more than 30 days).
Dealing with missing data
Where the publication does not provide enough data, and this would preclude reliable estimation of treatment effect, we will contact the trial authors for further information.
Assessment of heterogeneity
Heterogeneity (clinical and methodological diversity) will be assessed using the chi squared test of heterogeneity and the Higgins I2 statistic test (Higgins 2003) to check whether differences in results were due to chance alone. A chi² test with a P value of 0.10 will be considered to indicate the presence of heterogeneity.
Values of I2 fewer than 25% indicate a low level of heterogeneity and justify use of a fixed effect model for meta‐analysis. Values of I2 between 25% and 75% are considered moderate and a random effects model can be used. Values of I2 higher than 75% indicate high level of heterogeneity. In this case meta‐analysis is not appropriate
If (statistical) heterogeneity persists subgroup analyses or sensitivity analyses will be used to explore its causes.
Assessment of reporting biases
Where we suspect reporting bias, we will attempt to contact study authors asking them to provide missing outcome data.
Publication bias will be analysed with the funnel plot method.
Data synthesis
If clinically similar studies are available, we will pool their results in meta‐analyses.
We will use risk ratios (RR) or odds ratios (OR) of an event occurring with 95% confidence intervals (CI) and control events rates for reporting dichotomous data. We will use the fixed or random effects modelling for the meta‐analysis of dichotomous outcomes.
For continuous outcomes: if all trials measured the final outcome on the same scale we will pool the mean differences between the treatment arms using the mean difference method with 95% CI, or using the standardised mean difference method with 95% CI otherwise.
We will meta‐analyse ordinal scale outcomes as dichotomous data.
Values of I2 fewer than 25% indicate a low level of heterogeneity and justify use of a fixed effect model for meta‐analysis. Values of I2 between 25% and 75% are considered moderate and a random effects model can be used. Values of I2 higher than 75% indicate high level of heterogeneity. In this case meta‐analysis is not appropriate
Kappa statistics will be reported as a measure of objective agreement between observers with respect to data extraction, quality appraisal and assessment of potential bias in the selected studies.
Subgroup analysis and investigation of heterogeneity
With subgroup analysis we tend to explore possible sources of heterogeneity.
If sufficient trials are available, we will perform subgroup analysis to compare chronic pain evaluation within the group of preperitoneal repair techniques. We will investigate differences between these subgroups with the method described by Deeks et al. (Deeks 2001).
If possible we will investigate if there is a relation between early and chronic postoperative pain in each specific preperitoneal technique.
Sensitivity analysis
If there are sufficient included studies we plan to re‐analyse the results by excluding particular studies with a high risk of bias. We will also exclude studies with different end‐point definitions (eg dichotomous versus continuous outcomes) and explore this effect by sensitivity analysis.
