Hernia

, Volume 11, Issue 4, pp 335–339

A single-surgeon randomized trial comparing three composite meshes on chronic pain after Lichtenstein hernia repair in local anesthesia

Authors

    • Department of General SurgeryThe Central Hospital of Mikkeli
Original Article

DOI: 10.1007/s10029-007-0236-1

Cite this article as:
Paajanen, H. Hernia (2007) 11: 335. doi:10.1007/s10029-007-0236-1
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Abstract

Background

Chronic pain may be a long-term problem related to operative trauma and mesh material in Lichtenstein hernioplasty.

Study design

Inguinal hernioplasty was performed under local anesthesia in 228 patients (232 hernias) in day-case surgery by the same surgeon and exactly by the same surgical technique. The patients were randomized to receive either a partly absorbable polypropylene–polyglactin mesh (Vypro IIR 50 g/m2, 79 hernias), a lightweight polypropylene mesh (Premilene Mesh LPR 55 g/m2, 75 hernias) or a conventional densely woven polypropylene mesh (PremileneR 82 g/m2, 78 hernias). Pain, patients discomfort and recurrences of hernias were carefully followed at days 1, 7, 1 month, 1 and 2 years after surgery.

Results

The duration of operation (29–33 min) and the amount of local anesthetic (55–57 ml) were similar in the three groups. Two wound infections and four hematomas were detected with no difference between the meshes. Immediate pain reaction up to 1 month was statistically equal among the three meshes. After 2 years of follow-up, there were five recurrences (two in the Vypro group, one in the Premilene LP and two in the Premilene). A feeling of a foreign body, sensation of pain and patient’s discomfort were similar with all meshes.

Conclusion

There was no difference of pain and quality of life among a conventional polypropylene mesh, lightweight mesh or partly absorbable mesh in 2 years of follow-up, when the same surgeon operated on all patients with exactly the same technique.

Keywords

HernioplastyHerniorraphyInguinalDay case surgeryLocal infiltration anaesthesiaAmbulatory surgeryPolyglactinPolypropyleneInguinal neuralgia

Introduction

Symptomatic inguinal hernias are found in about 16% of adult men, and hernioplasty is one of the top three surgical procedures in most western countries. Approximately 12,000 inguinal herniorraphies are performed each year in Finland, over 80,000 operations in England and over 800,000 in the US [13]. Recent quality control studies have reported that chronic pain after inguinal hernia operation may occur in 10–30% of patients in a long-term follow-up [46]. The etiological factors include irritation or damage of inguinal nerves by sutures or mesh [7], inflammatory reaction against the mesh [8] or simply scar tissue [911]. Pain is reported to be neuropathic in character, related with younger age, to exist during physical activity and is more often associated with recurrent hernia surgery [46]. A recent systematic review of mesh techniques compared to non-mesh methods pointed out that there was no strong evidence that the use of meshes increased the rate of chronic pain [12].

Lichtenstein hernioplasty is a tension-free technique that uses a polypropylene mesh to support the inguinal muscular layer [13]. The preliminary reports of the Lichtenstein procedure were very optimistic with nil or a very low rate of chronic pain [14], but recent studies have pointed out that “mesh-induced pain” occurs more frequently than reported also in tension-free techniques [15]. First randomized follow-up studies indicated that the use of lightweight meshes may be associated with significantly less pain during exercise and the feeling of a foreign object compared to standard heavy meshes [1619]. The use of different meshes did not affect recurrence rates in two former reports [16, 17]. All the previous studies have included multiple surgical centers, multiple anesthetic techniques and operating surgeons. The aim of the present study was to compare the postoperative pain and the results of hernioplasty using three different meshes, while all other operative parameters were exactly the same.

Patients and methods

The study was conducted between March 2003 and August 2004 in the ambulatory surgery unit of our hospital. The study subjects (n = 228) were >18 years old with elective inguinal hernias (n = 232). The inclusion criteria were uni- or bilateral primary or recurrent inguinal hernia. The previous repairs did not include mesh hernioplasties. Patients fulfilling the day-case surgery criteria received written and oral information about the aims and content of the study in accordance with the Helsinki Declaration. The ethics committee in our hospital approved the study protocol. The exclusion criteria were femoral hernia, emergency operation, strangulated hernia and allergy to polypropylene.

Randomization was performed using numbered and sealed envelopes that were opened during the operation. The patients and staff conducting the postoperative assessment were both unaware of the treatment allocation. The patients were randomized to receive either a conventional densely woven polypropylene mesh (PremileneR 82 g/m2, Braun, Germany), a lightweight polypropylene mesh (Premilene Mesh LPR 55 g/m2, Braun, Germany) or a partly absorbable polypropylene–polyglactin mesh (Vypro IIR 50 g/m2, Ethicon, Hamburg, Germany). In patients with bilateral hernias, a different type of mesh was placed on each side; randomization determined on which side each mesh was implanted.

The patients were operated on by the same senior consultant surgeon with good experience of inguinal hernia surgery [20, 21]. The tension-free hernioplasty was performed by using a 9 × 13-cm trimmed mesh with a keyhole. The sac of indirect hernia was either resected or just inverted into the abdomen. If the hernia sac was large and direct, it was inverted with absorbable 2-0 DexonR (United States Surgical, Norwalk, CT). The mesh was trimmed and placed between the conjoint tendon, the inguinal ligament, the pubic bone and internal oblique aponeurosis [20, 21]. The ilioinguinal, genitofemoral and iliohypogastric nerves were identified if possible and carefully preserved. Care was taken not to involve the nerves within the sutures. The procedure was always performed under local anesthesia as an outpatient surgery. Local infiltration anesthesia was a 1:1 mixture of bubivacaine (Marcain 5 mg/ml, AstraZeneca, UK) and Citanest–adrenalin (10 mg/ml + 5 μg/ml, AstraZeneca, UK) with an average total volume of 40–60 ml [20]. After surgery the patient was followed up for 60–120 min to observe possible wound hemorrhage and then discharged. No prophylactic antibiotics were used. A 0.5–1.0-mg bolus of intravenous alfentanil was administered (Rapifen, AstraZeneca, UK) if the patient felt pain during the operation. Ibuprofen or paracetamol plus codeine were prescribed for postoperative pain.

Preoperative pain scores on a visual analogue scale (VAS) were measured for all patients during rest and moving (normal walking), as well as all patients completed a standard questionnaire form of previous disease history. Operative details were recorded including type and size of the hernia, volume of local anesthetic, operation time, bleeding and perioperative medication. All postoperative complications were recorded, and patients were telephoned with a set of questions at 1, 7 and 30 days, and 6, 12 and 24 months after surgery. Telephone questionnaires were performed by a dedicated research nurse blinded to the type of mesh. Pain scores (VAS) were also recorded postoperatively at the same time points. Patients who reported wound hematoma, infection, recurrence or chronic pain were recalled and examined clinically by the operating surgeon. Sick leave, time to return to normal activities, chronic pain, need of medication, feeling of a foreign object and satisfaction of the procedure were recorded at each time interval. Questions were based on the study of the Danish Hernia Database [5]. Ten patients of the original groups were dropped because they could not be reached (n = 5) or were deceased (n = 5). The reasons for the latter were elderly age with malignancies or congestive heart disease.

According to the power calculations, 65 subjects per treatment group were needed for the study to achieve a statistical power of 0.90 with an α of 0.05 (two tailed). The calculations were made for the duration of pain at 1 year after surgery, considering a 20% difference between the groups as clinically significant (incidence of chronic pain at 12 months: heavyweight mesh 25%, lightweight mesh or Vypro II mesh 5%). Earlier studies have disclosed some chronic pain by 23–25% of patients after Lichtenstein hernia repair with conventional mesh [20, 21]. Allowing a dropout rate of 5%, the study was set up to include randomization of >200 patients. The data analysis was carried out using SPSS for Windows, Release 10.0 (SPSS, Chicago, IL). The statistical evaluation was performed with ANOVA and chi-square test with Yates correction between the groups. P < 0.05 was regarded as significant for both tests.

Results

Between March 2003 and August 2004 a total of 232 hernias in 228 patients met the inclusion criteria and were randomized to one of the three meshes. Bilateral hernias were repaired simultaneously in two patients and after a 3-month interval in two patients. Because 10 patients were lost during the follow-up, a final 2-year analysis left a total of 218 patients with 222 hernias. There were no significant differences in patient characteristics among the three treatment groups (Table 1). Seven patients remained at the hospital overnight (four postoperative hematomas and three for social reasons).
Table 1

Patient characteristics and operative data described as means ± SD or raw numbers

 

VyproR

Premilene LPR

PremileneR

Number of hernias

79

75

78

Male/female

75/4

73/2

74/4

Mean age (±SD)

56 ± 13

55 ± 13

59 ± 15

BMI (±SD)

24 ± 3.2

25 ± 3.2

24 ± 2.5

Left/right

44/35

44/31

48/30

Direct/indirect

30/45

34/36

32/43

Combined

4

5

3

Size of defect (cm)

 <1.5

16

14

13

 1.5–3

40

35

35

 >3

23

26

30

Primary/recurrent

75/4

72/3

75/3

Mean operat. time (± min)

30 ± 8

33 ± 10

29 ± 8

Mean volume of local anesthesic (± ml)

55 ± 12

57 ± 18

56 ± 12

The differences were statistically nonsignificant

There were no statistical differences during the 1st week of postoperative complications among the treatment groups (Table 2). Wound complications were rare, and they occurred equally with all meshes. Two patients suffered from superficial wound infection. The removal of mesh was not necessary. Two thirds of the patients were able to walk and drive a car without pain during the 1st week (Table 2). There were no differences in the 1st week or 1st month convalescence among the treatment groups (Tables 2, 3). Many patients were elderly, and therefore their postoperative motility including car driving was limited. The patients with Premilene meshes tended to have longer sick leave than the other groups, but the difference was statistically nonsignificant (Table 3).
Table 2

First-week postoperative course of the patients

 

Number of patients

VyproR (n = 79)

Premilene LPR (n = 75)

PremileneR (n = 78)

Normal wound healing

76

74

76

Wound infection

1

0

1

Wound hematoma

2

1

1

Analgesic use

 Daily

23

16

31

 Sometimes

15

23

14

 None

39

36

33

Painless walking

72

66

66

Normal car drivinga

63

68

64

aMost of the patients were retired and used a car very seldom

Table 3

First-month postoperative course of the patients

 

Number of patients

VyproR (n = 79)

Premilene LPR (n = 75)

PremileneR (n = 78)

Wound swelling/bruises

7

5

3

Analgesic use

 Daily

1

2

5

 Sometimes

5

3

6

 None

69

67

65

Normal walking

74

71

74

Normal running

71

69

68

No problems in work

75

72

68

Sick leave

2

7

11

Long-term results indicated that the recurrences were rare (Table 4). Only five patients (2.3%) had a real recurrent hernia in the follow-up. There were three lateral (Vypro, Premilene LPR, Premilene R) and two medial (PremileneR, VyproR) recurrences. Undiagnosed femoral hernia was later operated on in one patient. The feeling of a foreign object was more common after 1 year (12–18%) than after 2 years (6–8%). Seven patients (3%) still needed occasionally analgesics due to groin pain after 2 years. Figure 1 show that early and late postoperative pain assessed by VAS was similar among the study groups, although there was a tendency (nonsignificant) towards increased pain following implantation of a conventional mesh after the 1st and 2nd year.
Table 4

Long-term results after 1st and 2nd year

 

VyproR (n = 74)

Premilene LPR (n = 72)

PremileneR (n = 75)

After 1st year

 Pain feeling

6

7

4

 Analgesic use

  Daily

1

1

0

  Sometimes

1

0

1

 Feeling of foreign body

12

18

12

After 2nd year

  Recurrences

2

1

2

  Analgesic use

4

2

1

  Feeling of foreign body

5

8

6

Ten patients from the original groups were dropped because they could not be reached (n = 5) or were deceased (n = 5)

https://static-content.springer.com/image/art%3A10.1007%2Fs10029-007-0236-1/MediaObjects/10029_2007_236_Fig1_HTML.gif
Fig. 1

Mean preoperative pain scores (VAS) of the three composite meshes compared to the scores after the 1st day, 1st week, 1st month, 1st year and the 2nd year, postoperatively. The standard deviations of bars varied between 0.9 and 2.4. There was no statistical difference among the treatment groups

Discussion

The present study indicated that mesh material had little effect on postoperative pain and convalescence after Lichtenstein hernioplasty when the same surgeon operated on the patients with exactly the same technique. Furthermore, Lichtenstein hernioplasty under local anesthesia was rapid and an effective surgical technique for inguinal hernia repair. Patients did not have urinary retention postoperatively, which is rather commonly seen after spinal anesthesia of elderly men [22]. The surgical technique was relatively simple and straightforward.

It is well known that traditional inguinal hernioplasties (Bassini, Shouldice, McWay etc.) have long-lasting pain due to tension [2]. In tension-free techniques chronic pain has also been reported in 20–30% of patients [5]. The etiological factors may include irritation or damage of inguinal nerves by sutures or mesh [7]. It was recently reported that polypropylene mesh used in the Lichtenstein operation would probably be associated with a higher inflammatory response (rise of serum C-reactive protein, fibrinogen and interleukin-6) and scar tissue formation than Bassini hernioplasty [8]. To avoid chronic nerve irritation and the feeling of a foreign object, recent multicenter studies have hypothesized that partially absorbable or lightweight meshes would improve operative outcome [1619]. First, Post and co-workers reported that lightweight polypropylene mesh would be preferable for Lichtenstein repair of inguinal hernia than conventional mesh after 6 months of follow-up [19]. After that, two randomized studies reported that the use of a partially absorbable lightweight mesh was associated with less chronic pain that a non-absorbable heavyweight mesh after 1 year [16] and 3 years [17]. The frequency of recurrences was similar with both meshes. All the previous studies were multi-center, performed in different countries and with several operating surgeons with multiple anesthetic techniques. This might have an effect on the measures of postoperative convalescense, pain and quality of life. The only variable parameter in the present study was mesh material.

Very recent laparoscopic study has indicated that fewer postoperative complications (i.e., formation of seromas) and improved quality of life can be achieved by reducing the amount of polypropylene in meshes used for laparoscopic hernia repair [23]. Foreign body sensations were also fewer when comparing lightweight meshes to conventional polypropylene mesh. Horstmann and co-workers followed their patients only 1 year after surgery [23], when a feeling of a foreign object is more common than after 2 years (Table 4). The present study indicated that postoperative seromas were not a big problem in Lichtenstein hernioplasty.

The recurrences (2.2%) in the present study occurred with all meshes, and they were medial in two patients. Another obese patient had a medial bulge after the insertion of a partially absorbable mesh (not recurrence). Because conventional meshes do not cause more pain and discomfort postoperatively than thinner meshes, it might be preferable to use heavy meshes particularly in obese patients to avoid bulging. The present study also indicated that severe chronic neuralgia was rare when the patients were properly followed up. Only seven patients (3.2%) needed analgesics after 2 years of hernia repair. When postoperative neuralgia occurred, it usually healed with nonoperative treatment. No patients were re-operated on due to chronic pain in the present series, but triple neurectomy has been suggested in severe cases [24].

The present study was powered to show a 20% difference in chronic pain among the three meshes. This is reasonable because many earlier studies have shown that about 30% of patients may have some chronic pain after inguinal hernioplasty [25]. If one would goal the study power to 15% difference or less, over 300 patients would be needed in each patient group, which means a multicenter and multisurgeon study. The only exact way to compare meshes in terms of postoperative pain and discomfort is to keep all other operative parameters unchanged (especially surgeon-related). The present study indicates that clinically important differences between the meshes were not found when over 200 patients were operated on by the same surgeon.

The present study has an economical impact on hernia surgery as well. Various new meshes are coming on the market every year. Usually they have newer materials and are more expensive than the conventional meshes. In the present study the least expensive mesh (10 × 13 cm) was PremileneR (20 €), then Premilene LPR (26 €), and the most expensive one was Vypro IIR (52 €). Local anesthesia also is simple and less expensive than spinal or general anesthesia. Earlier, we demonstrated that the learning curve of Lichtenstein hernioplasty in local anesthesia is relatively short, and there was not much difference in the long-term outcome among the surgical trainees and their consultant [21]. Results of the present study suggest that the choice of mesh has a minor impact on the long-term result if the operative technique is good.

Acknowledgments

The technical assistance of Mrs. Tellervo Summanen (technical assistance and Mrs. Pirjo Halonen (biostatistical analysis) are greatly appreciated. I thank Mrs. Lisa Kivela for revising the English. The experiments comply with the current laws of Finland.

Copyright information

© Springer-Verlag 2007