4 Evidence and interpretation
4.1.1 Outcomes of interest, against which the effectiveness of laparoscopic and open surgery were assessed, were primary outcomes of recurrence and persistent pain, and secondary outcomes of the rate of complications and persistent numbness, the duration of the operation, length of hospital stay, time to return to normal activities and quality of life.
4.1.2 A systematic review of the literature identified 37 randomised controlled trials (RCTs) that compared laparoscopic with open mesh repair of inguinal hernias in a total of 5560 participants. The effectiveness of laparoscopic surgery compared with different methods of open surgery (OFM, OPPM and OPM) was presented separately for the TAPP and TEP laparoscopic methods of repair. The best available data (individual patient data, or aggregate data from studies) were used to generate a meta-analysis of the effectiveness of TAPP and TEP procedures for different outcomes of effectiveness.
4.1.3 Laparoscopic surgery was associated with a statistically significant increase in operation time compared with open methods of hernia repair. Meta-analysis of 16 RCTs of TAPP repair demonstrated an overall increase of 13.33 minutes (95% CI 12.08 to 14.57) compared with open repair. Meta-analysis of eight RCTs of TEP repair demonstrated an overall increase of 7.89 minutes (95% CI 6.22 to 9.57) compared with open repair.
4.1.4 Laparoscopic surgery was associated with a significantly shorter time to return to usual activities in all of the studies that measured this outcome. Meta-analysis of seven RCTs of TAPP repair reported a hazard ratio (HR) of 0.66 (95% CI 0.58 to 0.75; p < 0.00001), corresponding to a return to normal activities approximately 3 days earlier than after open repair. Meta-analysis of five RCTs of TEP repair reported an HR of 0.49 (95% CI 0.42 to 0.56; p < 0.00001), approximating to a return to usual activities 4 days earlier than after open repair.
4.1.5 Both TAPP and TEP procedures demonstrated a statistically significant reduction in persistent numbness compared with open repair. Meta-analysis of eight RCTs comparing TAPP and open repair reported a relative risk (RR) of numbness of 0.26 (95% CI 0.17 to 0.40; p < 0.00001) in favour of TAPP repair. Meta-analysis of four RCTs comparing TEP with open repair reported an RR of 0.67 (95% CI 0.53 to 0.86; p < 0.002) in favour of TEP. One trial (n = 160) that randomised patients to TAPP or OPM repair reported no significant difference (RR 1.00, 95% CI 0.06 to 15.71 for TAPP) between the two techniques. Another trial that randomised 254 patients to TEP or OPM repair reported no significant difference (RR 2.57, 95% CI 0.11 to 62.38) between the two techniques. One RCT of TAPP compared with open repair showed that the reduction in numbness was maintained at 5-year follow-up (3% persistent numbness with TAPP compared with 23% with OFM repair).
4.1.6 Overall, there were fewer cases of persistent pain at 1 year post-operation after laparoscopic repair, compared with open repair, in both TAPP and TEP studies. Meta-analysis of eight RCTs of TAPP repair reported an RR of 0.72 (95% CI 0.58 to 0.88; p = 0.001) in favour of TAPP. Meta-analysis of four RCTs of TEP repair reported an RR of 0.77 (95% CI 0.64 to 0.92; p = 0.004) in favour of TEP repair. One RCT of TAPP compared with open repair showed that the reduction in pain was maintained at 5-year follow-up (2% persistent pain with TAPP compared with 10% with OFM repair).
4.1.7 The rates of recurrence were similar for laparoscopic and open repair. Meta-analysis of 15 TAPP RCTs reported a total of 26 recurrences out of 1052 TAPP procedures (2.5%) compared with 22 recurrences out of 1062 open repair procedures (2.1%; RR 1.18, 95% CI 0.69 to 2.02). Thirteen RCTs of TEP repair reported a total of 23 recurrences out of 1007 TEP repairs (2.3%), compared with 13 recurrences out of 1002 open repair procedures (1.3%; RR 1.61, 95% CI 0.87 to 2.98).
4.1.8 A number of studies reported the incidence of adverse events (complications such as haematoma, seroma, wound-related infection, mesh infection, vascular or visceral injuries and port-site hernia). Laparoscopic repair (both TAPP and TEP) was associated with fewer cases of wound-related infection and haematoma. However, TAPP repair was associated with a higher incidence of vascular and visceral injuries compared with open repair (0.13% vascular injuries with TAPP compared with 0% with TEP and open repair; 0.79% visceral injuries with TAPP compared with 0.16% with TEP and 0.14% with open repair).
4.1.9 One RCT randomised 52 patients with unilateral inguinal hernia to TAPP (n=28) or TEP (n=24) repair. There were no statistically significant differences between the procedures in terms of the duration of operation, intra-operative complications, incidence of haematoma, recurrence at 3-month follow-up, or time to return to usual activities.
4.1.10 There were no direct comparisons of TAPP and TEP methods of laparoscopic repair in patients with bilateral or recurrent hernia. Trials that evaluated the effectiveness of laparoscopic surgery compared with various forms of open surgery (OFM, OPPM and OPM) in the repair of recurrent inguinal hernias (six trials of TAPP and five trials of TEP) and bilateral inguinal hernias (six trials of TAPP and six trials of TEP) were consistent with the overall results for primary surgery of unilateral inguinal hernias.
4.1.11 The Assessment Group evaluated the effect of surgeons' experience on the duration of operation for laparoscopic repair (the 'learning effect'). Inexperienced surgeons (up to 20 procedures) were estimated to perform TAPP procedures in 70 minutes and TEP procedures in 95 minutes, compared with experienced surgeons, who were estimated to perform TAPP procedures in 40 minutes and TEP procedures in 55 minutes.
4.1.12 A recent study, published after the Assessment Group's initial review, randomised 2164 patients to laparoscopic surgery (10% TAPP, 90% TEP) or to OFM repair. Many of the results of this study were broadly consistent with the findings of the systematic review and did not affect the pooled results when they were incorporated into meta-analysis. This study reported a statistically significant increase in the recurrence rate with laparoscopic surgery (10.1% for TAPP and TEP combined compared with 4.9% after open repair at 2-year follow up, odds ratio [OR] 2.2, 95% CI 1.5 to 3.2). When the recurrence rates from the recent study were incorporated into meta-analysis of TEP compared with OFM repair, the RR of recurrence associated with laparoscopic surgery was increased from 1.61 (95% CI 0.57 to 4.60), in the original report, to 2.0 (95% CI 1.43 to 2.81). The incidence of serious complications was also significantly higher with laparoscopic repair (1.1%; TAPP and TEP combined) compared with open repair (0.1%; OR 11.2, 95% CI 1.3 to 1.7), although this had little effect on the results when incorporated into the meta-analysis. This study also reported a reduction in persistent pain after laparoscopic compared with open repairs (9.8% after laparoscopic surgery compared with 14.3% after open repair).
4.2.1 The literature review identified seven economic evaluations of laparoscopic surgery for inguinal hernia repair – three based on economic models and four based on primary studies. Only two studies (submitted by Ethicon Endo-Surgery and BARD Ltd) were relevant to the UK setting.
4.2.2 Ethicon Endo-Surgery provided a re-analysis of data from the MRC Laparoscopic Groin Hernia Trial, taking into consideration the repair of occult bilateral hernias. This model was based on the assumption that bilateral repairs in 30% of people with occult hernias would prevent the need for subsequent operation, and reduced the incremental cost effectiveness ratio (ICER) for laparoscopic surgery from £55,549 per quality-adjusted life year (QALY), as reported in the MRC Laparoscopic Groin Hernia Trial, to £15,000 per QALY. However, the model did not take into account the possibility that some people with occult hernias would not develop a clinically significant hernia.
4.2.3 The BARD submission compared the cost effectiveness of the Perfix plug (used in OPM repairs) with that of laparoscopic surgery on the basis of data presented in the previous guidance, issued in 2001 (see Section 8). BARD estimated that open plug and mesh repairs may be cost saving on the basis of assumptions that the additional device cost may be offset by reductions in the recurrence rate (0.5% Perfix plug compared with 2.2% with laparoscopic surgery reported in the previous guidance) and an increase in the number of perfix plug repairs undertaken as less costly day cases (91% perfix plug and 60% laparoscopic repairs undertaken as day cases).
4.2.4 The Assessment Group developed a Markov model that updates the paper by Vale l, Grant A and McCormack K (unpublished data 2003). The cost and outcome of various laparoscopic (TAPP and TEP) and open (OFM, OPPM and OPM) techniques were assessed in 1-year cycles over 5- and 25-year time horizons. All individuals entered the model at the point of initial hernia repair. In the first year, survivors were assumed to undergo a 3-month period of convalescence and then to return to full health. In subsequent years, individuals could be in a health state of no recurrence (with or without persistent pain or numbness), recurrent hernia proceeding to re-operation, recurrence without re-operation (at risk of emergency surgery for complications), or death (operative and all-cause mortality).
4.2.5 Inputs to the economic model on the costs and EQ5D utility estimates for the different health states were based on data from the MRC Laparoscopic Groin Hernia Trial. Theatre costs (£6.40 per minute) and in-hospital costs (£236 per day) were similar for open and laparoscopic procedures. The additional equipment and consumable costs of laparoscopic surgery were £167 per procedure when using predominantly reusable equipment (assuming all reusable devices are used on average 250 times a year for 5 years), or £788 per procedure when predominantly disposable equipment is used. Baseline estimates for operation length, hospital stay, operative mortality, recurrence, re-operation, persistent pain and numbness, time away from usual activities and health state utilities were taken from the best available data identified during this systematic review. Relative differences in the effectiveness of the different methods of open and laparoscopic repair were based on the meta-analysis results for the various outcomes, which were applied to these baseline parameters. Probabilities, costs and utilities were not considered to be fixed but were assigned a probability distribution to reflect uncertainty about their values. The same annual risk of recurrence, pain, numbness and relative effect sizes was used for primary and subsequent procedures. A constant annual risk for persistent pain, numbness and recurrence was assumed when extrapolating from years 6 to 25 of the model.
4.2.6 The results from the model showed that laparoscopic surgery (using reusable equipment) was associated with an increased cost of between £100 and £400 per procedure. Also, QALY differences between all of the techniques were small. Incremental analysis found the OPM method to be the most cost-effective method of open repair, driven by the duration of operation and hospital stay, which was the shortest with this procedure. However, when the same duration of operation and of hospital stay were assumed for all open procedures, the costs of OPM and OPPM techniques increased compared with OFM, and OFM became the most cost-effective method of open repair. TEP dominated TAPP, as it was less costly and more effective than the TAPP method of repair. The incremental cost of laparoscopic surgery compared with OFM was between £5000 and £12,000 per QALY at 5 years and between £2000 and £5000 per QALY at 25 years for TEP and TAPP, respectively. When the cost effectiveness of laparoscopic surgery was compared with OPM repair, laparoscopic surgery was not cost effective (with an ICER of £46,000–£606,000), and TEP was only cost effective (£20,000 per QALY) if the benefits extended for 25 years.
4.2.7 Sensitivity analysis for differences in the costs, utility and relative effectiveness of different methods of open and laparoscopic repair was undertaken to evaluate the effect of uncertainty in these areas; most of these had little effect on the cost effectiveness of laparoscopic surgery. However, the cost effectiveness of laparoscopic repair was shown to be highly dependent on the cost of the open repair comparator.
4.2.8 Sensitivity analysis that assumed that laparoscopic surgery did not improve the level of persistent numbness compared with OFM, increased the ICER of TEP from £2000 per QALY at baseline to £4000 per QALY at 25 years. Sensitivity analysis that assumed that laparoscopic surgery did not improve the level of persistent pain, increased the ICER of TEP from £2000 per QALY at baseline to £8000 per QALY at 25 years. Assumptions that laparoscopic surgery did not confer any benefits of reduced persistent pain or numbness increased the ICER of TEP to approximately £100,000 per QALY at 25 years. The use of reusable (approximately £170 per procedure) or disposable (approximately £790 per procedure) equipment in laparoscopic surgery had a huge impact on the cost effectiveness of surgery. Laparoscopic surgery using disposable equipment increased the ICER of TEP from £2000 per QALY at baseline to £14,000 per QALY at 25 years. In a separate analysis, the Assessment Group modelled the effect of repairing occult bilateral hernias on the cost effectiveness of laparoscopic surgery. This led to an increase in the cost of laparoscopic surgery compared with OFM, and a reduction in the probability of recurrence (as it has already been repaired) in the first year, increasing the ICER of TEP from £5000 per QALY at baseline to up to £10,000 per QALY at 5 years, depending on the prevalence and rate of progression of occult hernia.
4.2.9 A supplementary analysis was undertaken by the Assessment Team in order to evaluate the effect of inclusion of new data from the study published after completion of the original report (4.1.12). This also incorporated a number of sensitivity analyses evaluating the cost effectiveness of laparoscopic surgery, using data from the most recent trial, which led to more conservative estimates of the reduction in persistent pain and an increased RR of hernia recurrence with laparoscopic repair. Thus when the baseline recurrence rate for all laparoscopic surgery was increased from a cumulative rate of approximately 3% in the original base-case analysis to 10% at 2 years (based on the recent paper), the ICER of TEP compared with OFM was £6500 per QALY at a 25-year time horizon. When the RR of persistent pain was reduced from 0.77 in the original model, to 0.69 based on the results of the recent study, the ICER of TEP compared with OFM repair was £4000 per QALY at a 25-year time horizon. With these scenarios TAPP and TEP were associated with costs and effects that were increasingly similar.
4.3.1 The Committee reviewed the data available on the clinical and cost effectiveness of laparoscopic surgery for inguinal hernia repair, having considered evidence on the nature of the condition and the value placed on the benefits of laparoscopic surgery for inguinal hernia repair by people with the condition, those who represent them, and clinical experts. It was also mindful of the need to take account of the effective use of NHS resources.
4.3.2 The Committee heard evidence from experts that the incision resulting from open hernia repair may cause damage to the tissues and nerves, leaving some people with long-term pain and numbness. Experts further advised that all the open methods of repair (OFM, OPPM and OPM) would be expected to have similar incidences of persistent pain and numbness.
4.3.3 The Committee considered carefully the evidence from the RCTs on the potentially higher incidences of visceral and vascular injuries associated with laparoscopic hernia repair compared with open procedures. In addition, the evidence from the RCTs suggests that the incidences of these important adverse events may be different between the two laparoscopic procedures. Experts advised that this may have been a result of the relative lack of experience of surgeons in some of these early studies, and advised that there is currently no significant difference in the rate of adverse events between the two laparoscopic procedures when performed by experienced surgeons. The Committee considered carefully the recent study (4.1.12), which reported a significantly higher incidence of serious complications with laparoscopic repair compared with open repair (although this was not reported separately for TAPP and TEP repairs). Many of the adverse events may have been related to the effects of the general anaesthetic used in the patients undergoing laparoscopic repair coupled with the relatively poorer general health of patients recruited into this study (that is, two-thirds in ASA groups II and III) compared with patients included in the original systematic review. However, the Committee were persuaded that the patients in this trial were probably representative of the unselected patients undergoing operations for inguinal hernia in the NHS and therefore considered that inclusion of the data from this study in the overall analysis was appropriate.
4.3.4 The Committee appreciated that differences in the outcomes and adverse events of laparoscopic surgery, which may occur in practice and are apparent in the recent study (4.1.12), could result from differences in surgical experience. The Committee were persuaded that ongoing evaluation and review of the results of laparoscopic hernia repair was important and that this should be established at a national level to ensure that potentially serious events are identified and recorded in individual centres.
4.3.5 The Committee considered the uncertainty over the recurrence rate associated with laparoscopic surgery, which was statistically significantly higher than that associated with open repair when data from the recent study were incorporated. The Committee concluded that the risk of recurrence which was relatively low with both procedures, and that the increased risk of recurrence with laparoscopic surgery may be acceptable for some patients when the benefits (reduced pain and numbness, and earlier return to normal activities) are taken into consideration.
4.3.6 In summary, the Committee considered that laparoscopic repair of inguinal hernia was likely to result in considerably less postoperative pain and numbness than open repair. However, there was uncertainty over the rates of recurrence and of serious complications associated with laparoscopic surgery for primary repairs, which may be higher than those associated with the open procedure. On balance, the Committee concluded that laparoscopic surgery would be the preferred technique for the repair of recurrent hernias (as scar tissue from previous open repairs may be avoided) and bilateral hernias (repaired during the same operation and should also be an option for primary repair of unilateral hernias because of the reduced incidence of long-term pain and numbness and the potential for earlier return to normal activities.
4.3.7 The Committee considered that current evidence did not suggest which of the two available laparoscopic methods should be preferred for routine surgery, and noted the importance of the individual surgeon's experience in each method as a factor in determining the best choice. The Committee was advised that the TAPP approach enabled the surgeon to both view, and if required, effect a repair of an occult hernia on the contralateral side during a primary repair procedure. The TEP approach also allowed an occult hernia on the contralateral side to be seen, but required more dissection to facilitate repair.
4.3.8 The Committee was aware that laparoscopic (TAPP and TEP) methods of repair are technically more demanding than open repair, and that the clinical and the cost effectiveness of laparoscopic hernia repair are closely linked to the experience of the surgeon in the technique. The Committee heard evidence from experts that whilst surgeons are being trained in laparoscopic surgery, there is likely to be an increase in the duration of the operation, but were persuaded that this would not affect the overall longer-term cost effectiveness of the procedure. The Committee was persuaded of the importance of ensuring appropriate standards of training for laparoscopic hernia repair. They considered that, in light of the relatively small number of surgeons currently proficient in laparoscopic techniques (as compared with those undertaking open repair procedures), further training of surgeons in laparoscopic methods of repair will be required before this procedure can be more widely adopted.
4.3.9 The Committee considered it important that individuals be advised of the potential risk of complications associated with laparoscopic surgery. Laparoscopic surgery would not be appropriate for all, particularly those people unable to undergo or at higher risk from general anaesthesia, or in situations where the size or location of the hernia defect does not lend itself to laparoscopic surgery. Experts advised that individual surgeons tend to have a favoured method of open or laparoscopic repair. The Committee concluded that individuals should be given impartial advice as to the relative risks and benefits of laparoscopic repair compared with open repair during discussions with the surgeon at the time of referral, in order to facilitate an informed choice.
4.3.10 The Committee reviewed the data on the cost effectiveness of laparoscopic repair compared with the different methods of open repair, and considered the OFM technique to be the most clinically relevant comparator because it is the most common method of open repair and because of the absence of long-term data on the costs and outcomes of newer techniques (OPPM and OPM). The Committee considered that, taking all data reviewed into account, laparoscopic surgery (TAPP and TEP) is a cost-effective alternative to OFM repair. However, they noted that the choice of disposable or reusable equipment for use in laparoscopic hernia repairs had a significant effect on the ICER of the procedure. The Committee were therefore persuaded that, wherever possible, the use of reusable equipment was to be preferred.