Experience bias in laparoscopy vs. open studies
Overall, it is expected that laparoscopic inguinal hernia repair with mesh will have a lower postoperative chronic pain risk than open inguinal hernia repair mesh. This is because there are less potential nerves to irritate or injure in the retroperitoneum during laparoscopic surgery and no cutting or sewing of muscle in the groin region.
That said, as with any operation, mishandling of the structures, especially the spermatic cord, aggressive or non-delicate dissection in the area, and inappropriate mesh and/or tack placement can lead to chronic pain even with laparoscopic surgery. Technique and surgeon experience is super important as the learning curve is steep with this procedure.
Most studies about laparoscopic surgery outcomes are biased in favor of laparoscopy, as they tend to be published by experts in the field. The VA trial (L Neumayer et al) is one of few that actually evaluates laparoscopy vs open hernia repair among all surgeons, including mostly non-experts, and the results are in favor of open surgery (with lap best only for bilateral or recurrent hernia or if performed by experts).
If you read articles published by top open inguinal hernia experts, such as P Amid, their results are similar to that of laparoscopy in many facets, including chronic pain or inguinodynia.
Lastly,surgeons may be experienced in open and not lap, or in lap and not open, or perhaps in both open and lap. It would be incorrect to presume that most open surgeons are inexperienced. I would venture to guess however, since only 15% of all inguinal hernias in the USare done lap, that most open surgeons are not experienced in lap.