A single-surgeon randomized trial comparing three composite meshes on chronic pain after Lichtenstein hernia repair in local anesthesia
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- Paajanen, H. Hernia (2007) 11: 335. doi:10.1007/s10029-007-0236-1
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Chronic pain may be a long-term problem related to operative trauma and mesh material in Lichtenstein hernioplasty.
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.
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.
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.
KeywordsHernioplastyHerniorraphyInguinalDay case surgeryLocal infiltration anaesthesiaAmbulatory surgeryPolyglactinPolypropyleneInguinal neuralgia
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 [1–3]. 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 [4–6]. The etiological factors include irritation or damage of inguinal nerves by sutures or mesh , inflammatory reaction against the mesh  or simply scar tissue [9–11]. 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 [4–6]. 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 .
Lichtenstein hernioplasty is a tension-free technique that uses a polypropylene mesh to support the inguinal muscular layer . The preliminary reports of the Lichtenstein procedure were very optimistic with nil or a very low rate of chronic pain , but recent studies have pointed out that “mesh-induced pain” occurs more frequently than reported also in tension-free techniques . 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 [16–19]. 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 . 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 . 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.
Patient characteristics and operative data described as means ± SD or raw numbers
Number of hernias
Mean age (±SD)
56 ± 13
55 ± 13
59 ± 15
24 ± 3.2
25 ± 3.2
24 ± 2.5
Size of defect (cm)
Mean operat. time (± min)
30 ± 8
33 ± 10
29 ± 8
Mean volume of local anesthesic (± ml)
55 ± 12
57 ± 18
56 ± 12
First-week postoperative course of the patients
Number of patients
VyproR (n = 79)
Premilene LPR (n = 75)
PremileneR (n = 78)
Normal wound healing
Normal car drivinga
First-month postoperative course of the patients
Number of patients
VyproR (n = 79)
Premilene LPR (n = 75)
PremileneR (n = 78)
No problems in work
Long-term results after 1st and 2nd year
VyproR (n = 74)
Premilene LPR (n = 72)
PremileneR (n = 75)
After 1st year
Feeling of foreign body
After 2nd year
Feeling of foreign body
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 . 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 . In tension-free techniques chronic pain has also been reported in 20–30% of patients . The etiological factors may include irritation or damage of inguinal nerves by sutures or mesh . 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 . 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 [16–19]. 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 . 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  and 3 years . 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 . 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 , 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 .
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 . 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 . 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.
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.