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James Wellwood a Whipps Cross Hospital, London E11 1NR, b Health Economics
Research Group, Brunel University, Uxbridge, Middlesex UB8 3PH, c North Middlesex Hospital, London N18
1QX, d Medical
and Pharmaceutical Statistics Research Unit, University of Reading, PO
Box 240, Reading RG6 6FN, e MRC Biostatistics Unit, Institute of Public Health,
Cambridge CB2 2SR
Correspondence to: Mr Wellwood
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Abstract |
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Objective: To compare tension-free open mesh
hernioplasty under local anaesthetic with transabdominal preperitoneal
laparoscopic hernia repair under general anaesthetic.
Design: A randomised controlled trial of 403 patients
with inguinal hernias.
Setting: Two acute general hospitals in London
between May 1995 and December 1996.
Subjects: 400 patients with a diagnosis of groin
hernia, 200 in each group.
Main outcome measures: Time until discharge,
postoperative pain, and complications; patients' perceived health
(SF-36), duration of convalescence, and patients' satisfaction with
surgery; and health service costs.
Results: More patients in the open group (96%) than
in the laparoscopic group (89%) were discharged on the same day as the
operation (
2=6.7; 1 df; P=0.01). Although pain scores
were lower in the open group while the effect of the local anaesthetic
persisted (proportional odds ratio at 2 hours 3.5 (2.3 to 5.1)), scores
after open repair were significantly higher for each day of the first
week (0.5 (0.3 to 0.7) on day 7) and during the second week (0.7 (0.5 to 0.9)). At 1 month there was a greater improvement (or less
deterioration) in mean SF-36 scores over baseline in the laparoscopic
group compared with the open group on seven of eight dimensions,
reaching significance on five. For every activity considered the median
time until return to normal was significantly shorter for the
laparoscopic group. Patients randomised to laparoscopic repair were
more satisfied with surgery at 1 month and 3 months after surgery. The
mean cost per patient of laparoscopic repair was £335 (95% confidence
interval £228 to £441) more than the cost of open repair.
Conclusion: This study confirms that laparoscopic
hernia repair has considerable short term clinical advantages after
discharge compared with open mesh hernioplasty, although it was more
expensive.
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Key messages
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Introduction |
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The use of preformed mesh to repair inguinal hernias is gaining wide acceptance1 and is replacing repairs by suturing such as the Shouldice repair2 or Maloney darn.3 There is, however, disagreement about the relative merits of laparoscopic mesh placement by using three small abdominal incisions compared with placement of mesh by using an open approach through a standard groin incision. Using a randomised controlled trial we compared these two methods of inguinal hernia repair in terms of their clinical and patient based outcomes and health service costs. This paper details outcomes and cost results up to 3 months after surgery.
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Patients and methods |
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Trial design
Figure 1 illustrates the design of the trial. All patients with an
inguinal hernia seen at Whipps Cross or the North Middlesex Hospital
between May 1995 and December 1996 were considered for entry into the
study. Patients who were unfit for general anaesthesia, had
psychological complaints, were pregnant, were under 18 years of age, or
had a poor understanding of English were excluded. Written informed
consent was obtained at clinics before admission. Patients were
admitted to the day case unit on the morning of their operation and
were assessed by the anaesthetist. A randomisation schedule was
prepared by one person (DS) in balanced blocks randomly chosen to be of
length 4 or 6. To delay allocation to the latest possible time,
allocations were placed in consecutive opaque envelopes and the seal
broken in the anaesthetic room immediately before surgery. The surgeon
recorded operative details on a standardised form.
Surgical techniques
The trial protocol required patients having laparoscopic repair to
receive general anaesthesia and those undergoing open repair to have
local anaesthesia.
Laparoscopic repair was by a standard
three port technique, which has been reported
previously.
4 5
A 15×10 cm polypropylene mesh (Prolene,
Ethicon, Edinburgh) was placed in a preperitoneal pocket and was
stapled in position with the EMS multifeed staple gun (Ethicon,
Edinburgh). The peritoneum was replaced to exclude the mesh from the
peritoneal cavity and stapled in position. Bilateral laparoscopic
repair was performed with either two separate meshes as described above
or a single 28×10 cm mesh stretching across the pelvic floor.
Open repair
For the open technique the mesh was placed and
secured after the method of Lichtenstein.6 Early results
indicated a higher than expected incidence of purulent discharge from
wounds in patients having an open repair, and the last 82 (41%)
patients were given a single injection of antibiotic during the
operation.
Outcome measures
Figure 1 shows the outcome data collected at each time point.
Careful follow up of patients ensured the identification of the more
common surgical complications of the procedures. Patients indicated
their level of pain at various time points by using integer scores of 0 (no pain) to 10 (unbearable pain). A range of measures of function and
wellbeing from the perspective of the patient was assessed in the
trial. The first was the SF-36 health survey
questionnaire,7-11 which consists of eight multi-item
dimensions, each of which generates a score of between 0 and 100;
higher scores indicate higher levels of perceived health. The duration
of convalescence was assessed by using the diary card: patients
recorded whether they felt well enough to undertake usual activities
around the house (for example, washing and dressing), carry out social
activities, and drive a car. For the first 7 days after the operation
patients recorded their ability to move freely around the house and
walk short distances. At 3 months patients who were in employment were
asked when they had returned to work. Patients' level of satisfaction
was assessed by asking how satisfied they were with their treatment and
whether they would recommend their operation to a friend or relative
with a hernia.
Cost estimation
The cost analysis was undertaken from the perspective of the
health service. Measures of use of resources were divided into those
that were expected to vary by patient within each arm of the trial
(stochastic) and those that could reasonably be assumed to be constant
within each arm (fixed). Stochastic resource data were collected
prospectively and included time in theatre, the number of disposable
stapling guns used as part of the laparoscopic procedure, and
implications of complications on resources.
Statistical methods
The trial was originally designed to last 18 months and enrol 340 patients. By using data from a previous study5 we
estimated this sample size to provide 80% power at the two sided 5%
significance level to detect a feasible and important change of 26% in
analgesic use and a 19% change in days until normal activity.
2 tests for postoperative
complications and use of medication. The proportional odds model for
ordered categorical data18 was used to analyse the pain
scores; the comparison is presented as a proportional odds ratio of
less pain after open repair compared with laparoscopic repair. The
change from baseline of the SF-36 scores at 1 and 3 months after the
operation and the patient satisfaction data were analysed with the
Mann-Whitney U test.
For patients for whom data on postoperative complications were missing,
the total cost is underestimated. By treating such patients as censored
observations and by using Kaplan-Meier estimation, the mean (SE) cost
can be obtained.19-21
With sensitivity analysis, we carried out two alternative analyses to
assess the effect on differential cost of a "mainly disposable
consumables" policy and a "mainly reusable equipment" policy on
the basis of plausible clinical practice. In addition, we used
sensitivity analysis to assess the importance of variation in the unit
cost of stay on the day case unit and on a surgical ward.
Each estimate of difference between the groups is presented with a 95%
confidence interval. An intention to treat analysis was adopted,
including all patients who actually had an inguinal hernia and for whom
the operation began. No interim analyses were planned or conducted.
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Results |
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Characteristics of patients
Because of excellent recruitment and availability of resources the
trial was conducted over a 20 month period and enrolled 403 patients,
19% more than originally planned. A further 148 patients were
screened, of whom 59 refused to take part and 89 were considered
unsuitable. Three patients were excluded from the analysis (in one no
hernia was found, one had a femoral hernia, one withdrew after
randomisation but before surgery). Of the 400 remaining patients, 200 in each group, 268 were treated at Whipps Cross Hospital and 132 were
treated at the North Middlesex Hospital. Patients in the two surgery
groups were comparable (table 1) with the exception that more patients
undergoing laparoscopic repair (32) had hypertension than in the open
group (16). Of the 255 patients who were in paid employment, 59 had a
sedentary job, 109 had an active job, and 87 had a heavy job. The two
groups were comparable for both the physical activity of employment and
hours of employment.
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Surgical procedures
The two consultants performed 152 and 130 of the operations, and
118 were performed by senior registrars. There was no major imbalance
in the proportion of laparoscopic procedures nor of bilateral hernia
repairs performed by the consultants or trainees. The median duration
of surgery ("knife to skin" to "last stitch") was the same for
the two procedures both for unilateral repairs (45 minutes) and
bilateral repairs (65 minutes). After adjustment for covariates, there
was no difference in the duration of surgery for open and laparoscopic
repair of unilateral hernias (no time reduction;
6% to 5%).
Bilateral hernia repairs, however, were performed significantly more
quickly laparoscopically (16% time reduction; 3% to 27%). One
consultant performed laparoscopic significantly faster than open
repair, the second consultant took a similar time for each, and senior
registrars were significantly faster performing the open repair. When
the total time from entering the anaesthetic room until entering the
recovery room was analysed, medians of 15 and 10 minutes were added to
the operation time for patients in the laparoscopic and open repair
groups, respectively.
Intraoperative and anaesthetic complications
There were few intraoperative complications in either group. In
the laparoscopic repair group one patient required conversion to an
open procedure because of dense adhesions and two patients required
catheterisation during the operation to empty a full bladder. In the
open repair group four patients required administration of general
anaesthesia because of intolerance of the procedure under local
anaesthesia, one patient with bilateral hernias declined to have the
second side repaired, the vas deferens was inadvertently divided in one
patient, and nerves identified either as genitofemoral or
ileoinguinal were divided in eight patients. No patient in either
group sustained visceral injury.
Length of stay
Significantly more patients in the open repair group (191) than in
the laparoscopic repair group (177) went home on the day of the
operation (
2=6.7; 1 df; P=0.01). Of the 23 inpatient
transfers after laparoscopic repair, 14 were unplanned; six of these
were due to difficulty in passing urine while the others were due to a
combination of pain, apprehension, and general malaise. There was only
one unplanned admission in the open repair group. All nine patients
from the open group who were transferred as inpatients and 19 out of 23 patients from the laparoscopy group were discharged on the next day
(fig 2). Two patients in the laparoscopy group were discharged after 2 days and two further patients were discharged after 3 and 5 days.
Cox's proportional hazards model fitted to the length of stay, with
additional adjustment made for whether or not it was planned for the
patient to be kept in hospital, showed a significant increase in the
time until discharge for the laparoscopy group compared with the open
group (
2=44.7; 1 df; P<0.01).
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Recovery on the day care unit (first 4 hours)
Nausea, dizziness, and headache were more common after the
laparoscopic operation, which necessitates a general anaesthetic. The
number of patients who felt sick, dizzy, or had a headache at the time
points 1/2, 1, and 2 hours after laparoscopic repair was 58/198,
50/198, and 45/198, respectively, compared with 17/198, 12/197, and
10/194, respectively, for the open group (smallest
2=25.1; 1 df; P<0.01). There were also significantly
more patients in the laparoscopic group compared with the open repair
group with these symptoms at 4 hours, although 151 patients (38%) had
missing data, mostly because they had been discharged. Six patients in
the laparoscopic group required medication for nausea.
2=39.8; 1 df; P<0.01; odds ratio (2 hours) 3.46; 2.33 to 5.13). The proportional odds model fitted to the 142 laparoscopic
group and 108 open patients with scores available at 4 hours after
surgery also revealed less pain for the open group than the laparoscopy
group (
2=6.6; 1 df; P=0.01; 1.87; 1.15 to 3.02). No
analgesia was required on the day unit in 167 open repair patients
compared with 132 laparoscopic repair patients (
2=16.2;
1 df; P<0.01).
Patient diary cards
Diary cards for the first week (days 1-7) were completed by 395 patients (197 laparoscopy, 198 open), and 379 patients (188 laparoscopy, 191 open) completed the diary cards for each of weeks 2, 3, and 4.
2=14.3; 1 df; P<0.01; odds ratio (day 7) 0.49; 0.33 to
0.71) and also during week 2 (
2=5.0; 1 df; P=0.03; 0.66;
0.45 to 0.95). This is consistent with less use of pain relief observed
in the laparoscopic repair group during the first 2 weeks. There were
no significant differences in the pain scores between the two groups at
weeks 3 and 4 (table 2).
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Postoperative complications
Data on postoperative complications 1 week after surgery were
available for all patients, whereas the numbers of patients for whom
data were available at 1 month and 3 months were 383 (190 laparoscopy,
193 open) and 358 (182 laparoscopic, 176 open), respectively.
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2=8.7; 1 df; P<0.01)
during the first week after surgery.
Patient based outcomes
The SF-36 questionnaire was completed by 392 patients at baseline
(197 laparoscopic, 195 open), 369 at 1 month (184 laparoscopic, 185 open), and 353 at 3 months (179 laparoscopic, 174 open). At 1 month
after surgery there was greater improvement (or less deterioration) in
mean scores over baseline in the laparoscopic group compared with the
open group on each of the dimensions of the instrument except general
health (table 4). The differences observed were significant for five
dimensions. At 3 months after surgery there were greater improvements
in mean scores over baseline in the laparoscopic group for all items
except general health, but none of these differences reached
significance.
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Costs
Table 7 details use of patients' resources together with unit
costs. The major differences between the two groups in terms of use of
resources were the use of expensive consumables and more costly
equipment as part of the laparoscopic procedure.
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£105 to £241)). Ninety per cent of
open patients had a 3 month follow up cost less than £519.64 compared
with £875.94 for the same proportion of laparoscopic patients (figure
4). For a small proportion of patients in both groups, however, the
costs were far greater than these amounts because of
complications.
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£31 to £181). If a "largely disposable" policy were
followed in which, in addition to the disposables used for laparoscopic
repair in the base-case analysis, equipment such as trocars were also
disposable, the mean cost difference would increase to £523 (£419 to
£626). Plausible changes in the cost of an hour on the day case unit
and the cost of a day on a ward had a very small effect on the
differential cost of the two procedures.
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Discussion |
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This study compares the outcomes in patients treated on a day care unit by the most common method of laparoscopic repair (transabdominal, preperitoneal) with general anaesthesia or with a standard open mesh hernioplasty as described by Lichtenstein,6 with local anaesthesia. We have shown that for unilateral hernia repairs the laparoscopic operation does not necessarily take longer to perform than the open operation and could be quicker for bilateral hernia repairs. Laparoscopic repair is, however, technically more demanding and surgeons need specific training in the technique.
There were few operative complications in either surgical group, although, in common with earlier studies, 5 22-28 this trial was not powered to detect differences in serious but rare complications. Local neurovascular complications occurred mainly in the open repair group, and this is reflected in the increased incidence of postoperative numbness and pain in addition to the two cases of testicular atrophy. The risk of injury to nerves and vessels constitutes a valid indication for laparoscopic repair of recurrent hernias as the old wound and its associated scarring is avoided. No recurrent hernias have been found after 3 months' follow up.
Many open repair patients were discharged before the effect of the local anaesthesia had worn off, and they consequently experienced significantly less pain in the day care unit. On the morning after surgery and for the next 2 weeks, however, open repair patients had significantly more pain than laparoscopic repair patients. The observed reduction in postoperative pain after laparoscopic repair is probably due to the small incisions used and the smaller amount of dissection required for this repair and has been reported previously.5
The use of general anaesthesia may account for the lower proportion of laparoscopic patients who went home on the same day as surgery.29 Wound infection was defined as any purulent wound discharge, however asymptomatic. Four patients in the open group were readmitted for wound infection, although some purulent wound discharge occurred in 11% of open patients. This may seem high but close postoperative surveillance ensured accurate detection, and there is evidence that surgeons and hospital records may seriously underestimate the true incidence of clinically minor wound infections after hernia repair.30
This paper shows that neither form of repair is unequivocally more cost
effective. In terms of effectiveness all the patient based outcomes and
pain after the day of operation favoured laparoscopic repair or were
equivalent. This greater effectiveness, however, comes at a cost. On
the basis of use of resources in the trial centres, laparoscopic repair
has a mean cost £335 higher than the cost of open repair, with the
additional cost reflecting the higher cost of surgical equipment and
consumables with laparoscopic repair. In particular, the disposable
scissors and stapling gun alone cost at least £263 per patient in the
trial centres. Although they may not generate the same outcomes as seen
in this trial, greater use of reusable equipment could reduce the mean
difference in cost to as little as £75 (
£31 to £181).
Further analysis of outcomes and costs will be undertaken on data from 1 and 5 year follow up.
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Acknowledgments |
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The authors are grateful to Denise Walters and Jim Fong for their help in cost estimation. All views and any errors are the responsibility of the authors alone.
Contributors: JW initiated the study and research funding application, helped to design all aspects of the study, supervised and performed surgical procedures, interpreted results relating to clinical outcomes, and helped to write the paper. MJS contributed to the research funding application, helped to design the study (in particular patients based outcomes and costs), guided and participated in data analysis (particularly of patients based outcomes and costs), and helped to write the paper. DS participated in the initiation of the study and research funding application, performed surgical procedures, interpreted results relating to clinical outcomes, and helped to write the paper. GJN participated in the analysis of all data and helped to write the paper. CG helped to design the data collection instruments, collected and coded data, assisted the process of data analysis, and edited the paper. AW guided all data analysis (particularly methodological issues) and edited the paper. RS helped to initiate the study and design data collection instruments, interpreted results relating to anaesthesia, and edited the paper. DS participated in the initiation of the study and research funding application, designed the randomisation schedule, helped to design other aspects of the study, and edited the paper.
Funding: This research was funded by the Medical Research Council. The Health Economics Research Group receives funding through the Department of Health Policy Research Programme.
Conflicts of interest: MJS has acted as consultant to Ethicon but not relating to products associated with hernia repair.
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References |
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technique of nylon darn.
Lancet
1948;
ii:
45-48.(Accepted 27 March 1998)
but there is a cost
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