Inguinal hernia repair is one of the most common operations performed worldwide, with nearly 12 million operations performed each year. The lifetime risk of developing an inguinal hernia (IH) is estimated to be about 27% in men, and 3% in women [1].
Currently, surgical repair is the standard treatment for symptomatic IH, and there is increasing evidence to suggest that laparoscopy should be strongly considered by many, but not all, surgeons as the treatment of choice.
Totally extraperitoneal (TEP) and transabdominal preperitoneal (TAPP) repair are the most common methods of laparoscopic inguinal hernia repair (RLHI) in the United States [2].
A large systematic review showed that laparoscopic repair leads to a faster return to usual activities, and less postoperative pain and numbness, compared with open repair [3]. Other studies have shown that the laparoscopic technique also leads to a faster return to work, and some studies have suggested a decrease in chronic postoperative pain [4,5].
Health-related quality of life (HRQOL) outcomes are one of the most important elements of the definition of successful repair. Chronic pain after hernia repair is particularly distressing for patients, and is one of the most commonly encountered long-term postoperative complications [6]. The use of HRQOL surveys is ideal for measuring this subjective outcome.
Currently, most large studies examining chronic pain after IH repair have focused on the incidence of chronic pain after open repair [7,8]. More recently, some studies have shown that, when responses to HRQOL surveys, such as the Carolinas Comfort Scale (CCS), and the Surgical Outcomes Measurements System (SOMS), are analyzed, patients who underwent RLHI are less likely to experience chronic pain after laparoscopic surgery than those undergoing open repair [9,10].
On the other hand, a number of studies analyzing the use of mesh have shown that neither the use nor the type of mesh affects the development of chronic postoperative pain [11,12]. Regarding open repair, data show that younger patients are more likely to develop chronic postoperative pain, but there is still no consensus on that metric for laparoscopic treatment [13,14].
There is a paucity of data, not only on the incidence of chronic pain after laparoscopic hernia repair, but also on which patients are at greatest risk. The present study aimed to define both the incidence of chronic pain after RLHI and to report the predictors of this pain.
| Methods |
> Data collection
Patients undergoing RLHI with mesh, either via the TEP or TAPP approach, at a single institution were identified from a quality, prospectively managed database.
The database consists of all inguinal hernia repairs performed at NorthShore University HealthSystem , by 1 of 4 board-certified general surgeons, and is managed by research associates who prospectively collect preoperative, intraoperative, and postoperative data from patient records. within electronic medical records. That data extraction was performed in accordance with a protocol approved by the institutional review board.
Patients who underwent repair of a primary or recurrent unilateral or bilateral groin hernia (indirect, direct or femoral) were analyzed.
Patients who had nonreducible hernias (n = 70), those undergoing emergency repair (n = 9), and those who concomitantly underwent another separate procedure (n = 153) were excluded, as were those who did not They returned the quality of life survey after 6 months (n = 760).
Preoperative factors collected included: age at time of operation, body mass index, smoking status, specific risk factors for hernia (e.g., history of lifting weights, chronic cough), comorbidities, pain score on a visual analog scale (VAS), and hernia-specific information (e.g., duration, history of incarceration, laterality, type).
Intraoperative variables collected included: hernia size, duration of surgery, brand and type of mesh, use of dissector balloon and studs, ASA ( American Society of Anesthesiologists ) class, and whether there were any intraoperative complications.
Intraoperative complications were defined as any deviation from the standard surgical protocol obtained from the operative report. Postoperative variables collected included: length of stay, days of narcotic use, days to return to daily activity, return to work, emergency department visits, readmission or reoperation within 30 days of procedure, site infection surgery, mesh infections, development of a seroma or hematoma, and hernia recurrence.
> Surgical technique and postoperative care
All cases were performed by 1 of 4 surgeons specializing in minimally invasive surgery, at an academically affiliated institution. Each surgeon had performed at least 90 hernia repairs before starting the study. The PET technique used for RLHI has been previously described [15].
> HRQOL surveys
The SOMS and CCS surveys were distributed to patients preoperatively and postoperatively at 3 weeks, 6 months, and 1, 2, 3, 4, and 5 years.
The SOMS is a generic measure for quality of life after surgery, specifically focused on overall quality of life before and after surgery, offering valuable information about changes in quality of life as a result of surgery. The SOMS survey provides 7 outcomes: impact of pain, quality of pain, impact on VAS, fatigue, physical functioning, body image, and satisfaction.
Lower scores for pain impact, pain quality, VAS, and fatigue indicate better quality of life. Higher scores for physical functioning, body image, and satisfaction indicate better quality of life. The CCS was created specifically to evaluate and track quality of life outcomes in patients undergoing hernia repair, and is administered only postoperatively. The scale is well validated and is considered the tool of choice for evaluating quality of life in patients who underwent hernia repair [15].
This questionnaire contains 23 questions that refer to mesh sensation, pain, and movement limitations. Each question is scored on a 5-point scale, with 5 representing “disabling symptoms,” 4 representing “severe symptoms,” 3 representing “moderate/daily symptoms,” 2 representing “mild/annoying symptoms,” 1 representing “mild/not bothersome symptoms,” and 0 representing “no symptoms.”
The CCS was used in this study to show the percentage of patients with chronic pain over time. The SOMS was administered during the initial preoperative clinic visit. The 3-week postoperative surveys, including SOMS and CCS, were administered in clinic during follow-up visits. Additional surveys were emailed to patients at 6 months, and at 1, 2, 3, 4, 5, 7, and 10 years postoperatively.
The median follow-up time was 35 (12-60) months, both for quality of life surveys and clinical visits.
> Statistical analysis
Categorical data are summarized as frequency with percentage. Continuous data are summarized as mean with standard deviation, or median with interquartile range, as appropriate for the data distribution.
Comparisons between patients with and without chronic pain were made with the c2, Fisher’s exact, Wilcoxon rank-sum, or independent t test . Univariable and multivariable logistic regression analyzes were used to identify predictors of chronic pain.
Manual backward selection, with a P value < 0.10 to remain in the model, was used to select variables to include in the final multivariable analyses. All analyzes were performed with SAS 9.3 software (SAS Institute, Cary, NC), using 2-tailed tests.
| Results |
> Preoperative demographics
Between December 2008 and March 2020, 1952 adult patients underwent RLHI. After applying the exclusion criteria, 960 patients remained for analysis. In the total cohort, the mean age was 59 ± 14 years, and 9.3% of patients were women.
In the total cohort, 949 procedures were performed via PET and 11 via TAPP. Chronic pain was defined as a total CCS score greater than or equal to 3 at any point beyond 6 months postoperatively.
Once patients met criteria for chronic pain, they remained in the chronic pain group regardless of their scores on future CCS surveys. Of the 960 patients who were analyzed, 58 (6.0%) met the criteria for chronic pain. Younger patients were more likely to meet chronic pain criteria (55 ± 16 vs 60 ± 14 years; P = 0.009).
Additionally, patients who went on to develop chronic pain had higher preoperative VAS pain scores compared to patients who did not develop chronic pain ( P < 0.001). Steroid use, obstructive hernia, or history of weight lifting, chronic cough, constipation, diabetes, benign prostatic hypertrophy, or chronic obstructive pulmonary disease were all similar between groups ( all P > 0.05).
> Intraoperative characteristics
There were no intraoperative differences between patients who went on to develop chronic pain and those who did not. Mesh was used in all cases, and mesh size was not associated with the development of chronic pain.
The operative approach ( P = 0.498) and duration of surgery ( P = 0.962 for unilateral hernias, and P = 0.874) were both similar between the groups.
The most common mesh size was 10 x 15 cm, and it was used in 79.3% of cases in the group with chronic pain, and in 77.2% in those who did not experience chronic pain ( P = 0.746 ). No patient experienced an intraoperative complication. Conversion from PET to TAPP, dissector balloon use, stud use, and estimated blood loss were all similar between groups ( all P > 0.05).
> Postoperative results
The median length of hospital stay between groups was similar (7; interquartile range [IQR]: 6–8 vs 7; IQR: 6–8); P = 0.253). Patients who developed chronic pain used narcotic pain medication for a longer period postoperatively (2 vs. 1 day; P < 0.001), and returned to their activities of daily living later (7 vs. 3 days; P < 0.001), compared with those who did not develop chronic pain.
Within 30 days of surgery, there were no differences between the groups in emergency department visits or hospital readmissions. Three patients (0.3%) in the non-chronic pain group and 1 in the pain group (1.7%) developed a surgical site infection within 30 days of the operation ( P = 0.220). One patient in the group without chronic pain required reoperation for removal of an infected mesh. The recurrence rate was not different in the chronic pain group compared to the pain-free group (3.4% vs 1.2%; P = 0.182).
> Differences between surgeons
Surgeon 1 used multifilament polyester mesh 91.2% of the time, versus surgeons 2, 3, and 4 (80.1%, 79.7%, and 87.9%: P < 0.0001). Surgeon 1 used mesh size 16 x 12 cm 40.8% of the time, versus surgeons 2, 3, and 4 (11.7%, 0.9%, and 3.3%; P < 0. 0001), and surgeon 4 had patients with a lower median preoperative VAS pain than surgeons 1, 2, and 3 (0 [0–0] vs. 2 [1–3], 2 [1–4], and 2 [1–3]; P < 0.0001).
> SOMS
The mean SOMS scores improved, relative to preoperative scores, at 3 weeks postoperatively for: pain impact (9.7 ± 4.5 vs 8.6 ± 3.8; P = 0.005), pain quality (9.4 ± 4.0 vs 7.4 ± 2.8; P < 0.001), and VAS pain (2.4 ± 2.1 vs 1.8 ± 1.8; P < 0.001).
From 6 months to 5 years postoperatively, mean SOMS scores ranged from 6.8 to 7.5 for pain impact, 5.5 to 5.9 for pain quality, and 1.0 to 1. .3 for VAS pain ( P versus preoperative, for all < 0.01).
The SOMS survey was sent both pre- and postoperatively and, due to its holistic nature, this approach is not intended to measure the development of chronic pain, but rather to convey that patients have a better overall quality of life after RLHI, regardless of the development of chronic pain
> CCS
CCS pain scores at 3 weeks postoperatively indicated that 40.8% of patients were experiencing no symptoms, and 9.3% were experiencing moderate, severe, or disabling symptoms. At subsequent time points, the percentage of patients reporting no symptoms gradually increased. From 6 months to 5 years postoperatively, the percentage of patients without symptoms ranged between 69.9% and 81.0%, the percentage with mild bothersome symptoms ranged between 15.9% and 26.1%, and the percentage with moderate or worse symptoms ranged from 3.2% to 5.4%.
> Chronic pain (CCS ≥ 3)
It was found that 6.0% of patients reported moderate, or daily, or worse symptoms (CCS ≥ 3) at some point beyond 6 months postoperatively.
Predictors were identified, including: age less than 45 years, female sex, VAS pain ≥ 1, use of multifilament polyester mesh, previous ipsilateral inguinal hernia repair, ASA class 2, 3, or 4, and intraoperative placement . of a urinary catheter.
The majority of patients reported 2 (26.9%) or 3 (49.2%) of the identified predictive risk factors. A minority of patients reported 0 to 1 (8.8%) or > 3 (15.0%) of the risk factors. The rate of development of chronic pain increased dramatically for each additional risk factor reported.
| Discussion |
In this study, it was found that there are notable differences between patient demographics and postoperative outcomes, when comparing patients who went on to develop chronic pain and those who did not. Age, VAS pain score, days to cessation of narcotic pain medication use, and days to return to activities of daily living were all different between groups.
On the other hand, in the multivariate analysis, it was found that younger age, female sex, those with pain score ≥ 1 on the VAS, patients with a previous hernia repair on the same side, a high ASA class, use of multifilament polyester mesh, and intraoperative placement of a urinary catheter, were all predictors of chronic pain at 6 months or later postoperatively.
Chronic pain , in general, is extremely variable among American adults, ranging from 11% to 40%, and there is a lot of variation between different populations [16]. A cut-off point of ≥3 on the CCS survey was used to define chronic pain postoperatively.
The CCS asks questions related to mesh sensation, pain, and limitations of movement during various activities. A score ≥ 3 represents “moderate/daily symptoms” and therefore it was considered that patients describing daily symptoms could fall into the chronic pain category.
In previous studies, definitions of chronic pain have varied; The most common definition in the literature was pain persisting beyond the normal tissue healing time (assumed to be 3 months), as defined by the International Association for Study of Pain , and which has been extended to the past 6 months, as which increases the use of synthetic materials, such as non-absorbable meshes [17,18].
Other publications use different cut-off points in the VAS score to define chronic pain [19,20]. The authors of this work decided that, rather than using a single score like the VAS, a multidimensional score, composed of several mesh-specific measurements, might be the most appropriate way to measure and define chronic pain.
Previous studies including only patients undergoing open inguinal hernia repair have shown that the presence of new recurrent hernias, severe pain early after the primary operation, and young age (< 40 years) were predictors of long-standing inguinal pain. [8,21]. More recent studies comparing laparoscopic and open repairs have shown that chronic pain is statistically significantly more common after open mesh repair than after laparoscopic TEP repair [9,10].
Younger age was associated with a higher incidence of chronic pain during follow-up in the present study, which has been well documented in the literature, in patients undergoing both open and laparoscopic repair [21,22].
This finding may be explained by a greater sensitivity to pain in young patients, or by a willingness to be more communicative about their pain in questionnaires. Female sex was also found to be a risk factor for chronic pain.
This finding is consistent with studies showing that female patients have a higher risk of developing chronic pain after other types of surgical procedures [23], and that higher risk may be due to female patients having greater anxiety related to pain (i.e., anticipatory anxiety) [24].
Multiple studies have shown that preoperative pain is a risk factor for chronic pain [19,25]. The finding that high preoperative VAS pain scores in this study were associated with chronic postoperative pain is not surprising, and may be an indicator that these patients have a lower threshold for pain, or an anatomical difference predisposing to pain. chronic.
In relation to the other predictive factors found, it was hypothesized that patients with high ASA scores may have comorbidities that increase the inflammatory response and make them susceptible to chronic pain.
Finally, the intraoperative use of urinary catheters was found to predict the development of chronic pain. Urinary catheters were placed only selectively (6.5% of all cases), and all surgeons shared the same practice, only placing catheters in patients who had a history of preperitoneal surgery, for example, a prostatectomy, or urinary retention. preoperative. The finding that intraoperative placement of a urinary catheter leads to chronic pain has not been previously shown in the literature, but may be related to neuropathic dysfunction.
Cessation of narcotics in the acute period is something that has particularly been addressed recently in the literature and, therefore, patients in the chronic pain group can be expected to take narcotic medications longer than those who do not experience pain. chronic. As the medical community attempts to decrease the prescribing and use of narcotic medications to limit opioid abuse, this finding is particularly pertinent.
At our institution, all patients are sent home with prescriptions for ibuprofen and hydrocodone or acetaminophen, or, more recently, tramadol. Finally, patients in the chronic pain group returned to their usual daily adult activity later compared to those who did not develop chronic pain, and it is not clear whether this is a clinically important finding, but it may represent impaired healing or increased sensitivity to pain.
Studies addressing whether the use of mesh affects whether a patient experiences chronic postoperative pain have revealed that mesh can be used without fear of causing a higher rate of chronic pain and, in particular, self-fixing meshes do not increase the incidence of pain. chronic when compared to lightweight sutured meshes [11,12]. Additionally, the benefits of decreased recurrence rates provided by mesh cannot be underestimated.
Although the use of mesh was not compared in relation to the development of chronic pain, the use of a multifilament polyester mesh was found to be a predictor of chronic pain. Polyester multifilament mesh may cause a foreign body sensation compared to other lighter types of mesh, and may explain the higher CCS scores.
Polyester multifilament mesh is used primarily at the authors’ institution; However, based on the results of this study, the surgical group will reconsider and may switch to self-fixation meshes in the future.
This study has several limitations. Like any retrospective study, the results are limited by the data contained in the electronic medical record, and the authors are hesitant to draw too strong conclusions about the predictors of chronic pain.
Another limitation is that some patients who may have had postoperative complications or recurrences may have been treated at another hospital outside of the NorthShore University HealthSystem, and could not be captured.
Additionally, low survey response rates may have affected the chronic pain rates found; However, it was hypothesized that patients with chronic pain may have had a greater probability of returning the questionnaires due to dissatisfaction with the operation, artificially increasing the percentage of patients with chronic pain.
Another limitation is that there was no preoperative CCS survey, and to address that, preoperative pain score ≥ 1 on a VAS was used as a surrogate. The worst pain scores on the preoperative scale were controlled for during the multivariate analysis for chronic pain and were found to be a statistically significant predictor.
Additionally, the use of preoperative analgesic medication (e.g., gabapentin, TAPP blockers), may have differed throughout the study period, because these medications were not captured in the database; Also because data on preoperative narcotic use were not collected, there is potential for bias in concluding that there is a difference in postoperative narcotic use in the chronic pain group.
A final limitation is that, although most operations were performed in a similar manner, there may have been slight variation in the techniques used based on surgeon preference; but you could say that this is actually a benefit, because it increases the generalizability of the study
In conclusion, this study implies that patients who are at high risk of experiencing chronic pain are: younger in age, female, have groin pain preoperatively, have a prior inguinal repair on the same side, have an elevated ASA class, use of multifilament polyester mesh, and placement of a urinary catheter during the operation.
The authors suggest that surgeons be aware of these factors and counsel their patients appropriately regarding the development of chronic pain.
