Bypassing the post-anaesthesia care unit after elective hip and knee arthroplasty: a prospective cohort safety study.

Following knee and hip arthroplasty, transfer to a recovery area immediately following surgery and before going to ward might be unnecessary in low-risk patients. Avoiding the recovery area in this way could allow for more targeted use of resources for higher risk patients, which may improve operating theatre flow and productivity. A prospective single-centre cohort study on the safety of criteria for bypassing the post-anaesthesia care unit in elective hip and knee arthroplasty was designed. Criteria were: ASA physical status < 3; peri-operative bleeding < 500 ml; low postoperative discharge-score (modified Aldrete-score); and an uncomplicated surgical and neuraxial anaesthesia procedure. The primary outcome was the number of patients in need of secondary readmission to the post-anaesthesia care unit. Events within the first 24 postoperative hours were recorded, along with readmission and complication rates. A total of 696 patients were included, with 287 (41%) undergoing total hip arthroplasty, 274 (39%) undergoing total knee arthroplasty and 135 (19%) undergoing unicompartmental knee-arthroplasty. Of these, 207 (44%) bypassed the post-anaesthesia care unit. Patients all received multimodal analgesia without peripheral nerve blockade. Only one patient in the ward group required secondary readmission to the post-anaesthesia care unit. Within 24 h, 151 events were reported, with 41 (27%) in the ward group and 110 (73%) in the post-anaesthesia care unit group. Two events in each group occurred within 2 hours of surgery. No complications were attributed to bypassing the post-anaesthesia care unit. The use of simple pragmatic criteria for bypassing the post-anaesthesia care unit for patients undergoing knee and hip arthroplasty with spinal anaesthesia is possible and associated with significant reduction of post-anaesthesia care unit admission and without apparent safety issues. Confirmation is needed from other studies and external validity should be interpreted cautiously in centres with different peri-operative regimens, organisational and staffing structures.

A narrative review on the non-surgical treatment of chronic postoperative inguinal pain: a challenge for both surgeon and anaesthesiologist.

INTRODUCTION: Chronic pain is one of the most frequent clinical problems after inguinal hernia surgery. Despite more than two decades of research and numerous publications, no evidence exists to allow for chronic postoperative inguinal pain (CPIP) specific treatment algorithms. METHODS: This narrative review presents the current knowledge of the non-surgical management of CPIP and makes suggestions for daily practice. RESULTS: There is a paucity for high-level evidence of non-surgical options for CPIP. Different treatment options and algorithms have been published for chronic pain patients in the last decades. DISCUSSION AND CONCLUSION: It is suggested that non-surgical treatment is introduced in the management of all CPIP patients. The overall approach to interventions should be pragmatic, tiered and multi-interventional, starting with least invasive and only moving to more invasive procedures upon lack of effect. Evaluation should be multidisciplinary and should take place in specialized centres. We strongly suggest to follow general guidelines for treatment of persistent pain and to build a database allowing for establishing CPIP specific evidence for optimal analgesic treatments.

Preoperative high-dose glucocorticoids for early recovery after liver resection: randomized double-blinded trial.

BACKGROUND: Glucocorticoids modulate the surgical stress response. Previous studies showed that high-dose preoperative glucocorticoids reduce levels of postoperative inflammatory markers and specific biomarkers of liver damage compared with placebo, and suggested a reduced complication rate and shorter hospital stay after liver surgery. However, there are no studies with a clinical primary outcome or of early recovery outcomes. The aim of this study was to investigate whether a single high dose of preoperative glucocorticoid reduces complications in the immediate postoperative phase after liver surgery. METHODS: This was a single-centre, double-blinded, parallel-group RCT investigating preoperative methylprednisolone 10 mg/kg (high dose) versus dexamethasone 8 mg (standard-dose postoperative nausea prophylaxis) in patients scheduled for open liver resection. The primary outcome was number of patients with a complication in the postanaesthesia care unit; secondary outcomes included duration of hospital stay, pain and nausea during admission, and 30-day morbidity. RESULTS: A total of 174 patients (88 in high-dose group, 86 in standard-dose group) were randomized and analysed (mean(s.d.) age 65(12) years, 67.2 per cent men); 31.6 per cent had no serious co-morbidities and 25.3 per cent underwent major liver resection. Complications occurred in the postanaesthesia care unit in 51 patients (58 per cent) in the high-dose group and 58 (67 per cent) in the standard-dose group (risk ratio 0.86, 95 per cent c.i. 0.68 to 1.08; P = 0.213). Median duration of hospital stay was 4 days in both groups (P = 0.160). Thirty-day morbidity and mortality rates were similar in the two groups. CONCLUSION: A high dose of preoperative glucocorticoids did not reduce acute postoperative complications after open liver resection compared with a standard dose. Registration number: NCT03403517 (http://www.clinicaltrials.gov); EudraCT 2017-002652-81 (https://eudract.ema.europa.eu/).

Hypoxemia following hospital discharge after fast-track hip and knee arthroplasty - A prospective observational study subanalysis.

BACKGROUND: Post-operative hypoxemia is prevalent in hospitalized patients and may adversely affect recovery. However, little data exist on the post-discharge phase or details on duration, severity and potential risk factors. Thus, we investigated the incidence and risk factors for severe desaturation during the first post-operative week after THA/TKA by continuous nocturnal oxygen saturation monitoring. METHODS: The study was a secondary analysis of a prospective cohort study of 112 patients undergoing fast-track THA/TKA. Patients with known sleep apnoea were excluded. Oxygen saturation and heart rate were recorded by a wireless wrist-worn pulse oximeter 2 nights before and 7 nights after surgery. Data on demographics, opioid consumption and cognitive function were collected from medical charts, patient diaries and clinical testing respectively. The primary outcome was occurrence of severe desaturation defined as periods with saturation <85% lasting ≥10 minutes. Secondary outcomes included description of various saturation levels and relevant risk factors. RESULTS: Severe oxygen desaturation occurred in 35% of the patients during the first post-operative week. Duration and severity of hypoxemic episodes increased after the first post-operative day. Pre-operative episodes of hypoxemia significantly increased the risk of post-operative hypoxemic events (OR 2.4-4.4, CI 0.4-46), while pre- and post-operative opioid use, age, gender, ASA classification, type of surgery or anaesthesia were significantly related to the development of post-operative hypoxemia. CONCLUSIONS: One third of the patients suffered from increased and prolonged episodes of severe nocturnal hypoxemia during the first week after THA/TKA discharge. Increased risk for severe hypoxemic episodes was related to pre-operative hypoxemia.

Continuous vital sign monitoring after major abdominal surgery-Quantification of micro events.

INTRODUCTION: Millions of patients undergo major abdominal surgery worldwide each year, and the post-operative phase carries a high risk of respiratory and circulatory complications. Standard ward observation of patients includes vital sign registration at regular intervals. Patients may deteriorate between measurements, and this may be detected by continuous monitoring. The aim of this study was to compare the number of micro events detected by continuous monitoring to those documented by the widely used standardized Early Warning Score (EWS). METHODS: Fifty patients were continuously monitored with peripheral arterial oxygen saturation (SpO2 ), heart rate (HR), and respiratory rate (RR) the first 4 days after major abdominal cancer surgery. EWS was monitored as routine practice. Number and duration of events were analyzed using Fisher's exact test and Wilcoxon rank sum test. RESULTS: Continuous monitoring detected a SpO2 <92% in 98% of patients vs 16% of patients detected by EWS (P < .0001). Micro events of SpO2 <92% lasting longer than 60 minutes were found in 58% of patients by continuous monitoring vs 16% by the EWS (P < .0001). Fifty-two percent of patients had micro events of SpO2 <85% lasting longer than 10 minutes. Continuous monitoring found tachycardia in 60% of patients vs 6% by the EWS. Frequency of events for bradycardia, tachypnea, and bradypnea showed similar patterns. CONCLUSION: Very low SpO2 and tachycardia in post-operative patients are common and under-diagnosed by the EWS. Continuous monitoring can discover these micro events and potentially contribute to earlier detection and, potentially, result in prevention of clinical complications.

Analgesic consumption trajectories in 8975 patients 1 year after fast-track total hip or knee arthroplasty.

BACKGROUND: Persistent or increased long-term opioid consumption has previously been described following total hip- (THA) and knee arthroplasty (TKA). However, detailed information on postoperative analgesic consumption trajectories and risk factors associated with continued need of analgesics in fast-track THA and TKA is sparse. METHODS: This is a descriptive multicentre study in primary unilateral fast-track THA or TKA with prospective data on patient characteristics and information on reimbursement entitled dispensed prescriptions of paracetamol, non-steroidal anti-inflammatory drugs, opioids, anticonvulsants and antidepressants 1 month preoperatively and 1 year postoperatively. Patients were stratified according to preoperative opioid use. Postoperative analgesic consumption trajectories were stratified as increased, decreased or no use compared to the preoperative period. RESULTS: Of 8975 patients (4849 THA/4126 TKA), 33.9% had relevant reimbursed prescriptions 9-12 months postoperatively. Of 2136 (23.8%) patients with preoperative opioid use, 3.4% had unchanged opioid consumption at 9-12 months postoperatively. However, increased opioid consumption after 9-12 months occurred in 17.6 (TKA) and 10.2% (THA) compared to 9.9 and 6.3% in opioid-naive TKA and THA patients, respectively. Increased NSAID and paracetamol use was seen in 11.5 and 12.4% of all patients. Preoperative analgesic use (any), TKA, psychiatric disorder, tobacco abuse, cardiac disease and use of walking aids were associated with increased opioid consumption. CONCLUSION: Continued and increased opioid and other analgesic use occur in a clinically significant proportion of fast-track TKA and THA patients 9-12 months postoperatively, suggesting treatment failure and need for early intervention. Preoperative risk assessment may allow identification of patients in risk of increased postoperative opioid consumption. SIGNIFICANCE: We found a considerable fraction of patients with continued or increased opioid consumption 9-12 months after fast-track THA and TKA. Increase in opioid consumption was more frequent in preoperative opioid users than opioid-naive patients, but a pattern of increased analgesic consumption was present across all analgesics. Our data demonstrate a need for increased focus on long-term analgesic strategies and postoperative follow-up after THA and TKA, especially in preoperative opioid users.

Incidence and related factors for intraoperative failed spinal anaesthesia for lower limb arthroplasty.

BACKGROUND: Spinal anaesthesia is the preferred choice for total hip- and knee arthroplasty (THA/TKA), due to the claimed superior outcome profile, relative simple technique and without the need for advanced airway support. However, choosing and informing about spinal anaesthesia should also include the risk for intraoperative failed spinal anaesthesia with associated pain, discomfort and suboptimal settings for airway management. Small-scale studies suggest incidences from 1 to 17%; however, no multi-institutional large data exists on failed spinal incidence and related factors during THA/TKA, hindering evidence-based information and potential anaesthesia stratification. METHODS: In a sub-analysis, data from a prospective study on spinal anaesthesia for THA/TKA were examined for incidence of intraoperative conversion to general anaesthesia. Potential perioperative factors (age, gender, American Society of Anaesthesiologist (ASA) score, height, weight, BMI, procedure, bupivacaine dosage and duration of time from spinal administration until end of surgery) were analysed with logistic regression for relation to failed spinal anaesthesia. RESULTS: In all, 1451 patients were included for analysis, whereof 57 (3.9%) had failed spinal anaesthesia. Spinal failure patients were significantly younger (61 vs. 67 years, P = 0.003), and operation time longer in the failed spinal group vs no-failure, respectively (133 vs. 89 min, P < 0.001). No significant differences were found with regard to bupivacaine volume, gender, ASA-score, height, weight, BMI or THA vs. TKA. CONCLUSION: Failed spinal anaesthesia for THA and TKA is a relatively frequent occurrence and identification of risk patients is not feasible. These results should be considered when choosing anaesthesia and included in the information to patients.

Technological aided assessment of the acutely ill patient - The case of postoperative complications.

Surgical interventions come with complications and highly reported mortality after major surgery. The mortality may be a result of delayed detection of severe complications due to lower monitoring frequency in the general wards. Several studies have shown that continuous monitoring is superior to the manually intermittent recorded monitoring in terms of detecting abnormal physiological signs. Hopefully improved observations may result in earlier detection and clinical intervention. This narrative review will describe current monitoring possibilities for postoperative patients and how it may prevent complications. Several wireless systems are being developed for monitoring vital parameters, but many of these are not yet validated for critically ill patients. The ultimate goal with patient monitoring and detect of events is to prevent postoperative complications, death and costs in the health care system. A few studies indicate that monitoring systems detect deteriorating patients earlier than the nurses, and this was associated with less clinical instability. An important caveat of future devices is to assess their effect in relevant patient populations and not only in healthy test-subjects. Implementation of novel technologies is expensive although expected to be cost-effective if just few adverse events can be prevented. The future is here with promising devices and the possibility to give an unprecedented precise risk estimation of adverse post-surgical events. Next step is to integrate existing evidence based treatment algorithms to demonstrate the clinical efficacy of implementing the new technology.

Early patient-reported outcomes versus objective function after total hip and knee arthroplasty: a prospective cohort study.

AIMS: The purpose of this study was to assess early physical function after total hip or knee arthroplasty (THA/TKA), and the correlation between patient-reported outcome measures, physical performance and actual physical activity (measured by actigraphy). PATIENTS AND METHODS: A total of 80 patients aged 55 to 80 years undergoing THA or TKA for osteoarthritis were included in this prospective cohort study. The main outcome measure was change in patient reported hip or knee injury and osteoarthritis outcome score (HOOS/KOOS) from pre-operatively until post-operative day 13 (THA) or 20 (TKA). Secondary measures were correlations to objectively assessed change in physical performance (paced-walk, chair-stand, stair-climb tests) at day 14 (THA) or 21 (TKA) and actual physical activity (actigraphy) measured at day 12 and 13 (THA) or 19 and 20 (TKA). RESULTS: Patients reported improved physical function (HOOS or KOOS) pre-operatively until day 13 (THA) or 20 (TKA) with a mean difference of 7 (95% confidence interval (CI) 1 to 13, p = 0.033) and 6 (95% CI 1 to 12, p = 0.033) percentage points, respectively. By contrast, objectively assessed physical function and activity declined, with no correlations between subjective and objective assessments for either THA or TKA patients (r2 ≤ 0.16, p ≥ 0.314). CONCLUSIONS: Early improvement in patient-reported physical function after THA/TKA does not correlate with objectively assessed function, and patient reported outcomes should not be used as the only measure of recovery. Cite this article: Bone Joint J 2017;99-B:1167-75.

Clinical, nociceptive and psychological profiling to predict acute pain after total knee arthroplasty.

BACKGROUND: Pre-operative identification of high-pain responders for acute pain after total knee arthroplasty (TKA) could lead to targeted analgesic trials and individualized analgesic strategies to improve recovery and potentially reduce the risk of persistent post-surgical pain. The aim of this study was to use simple clinical tests and questionnaires to identify predictive nociceptive and psychological factors for acute post-TKA pain. METHODS: Sixty consecutive TKA patients were included in a prospective descriptive study of pain during a 5-m walk-test 24 h post-operatively as the primary outcome. Predictive variables collected prior to surgery included demographics, nociceptive testing (pressure pain threshold (PPT), cold pressor tolerance, electrical pain threshold and tolerance) and psychological profile (pain catastrophizing scale (PCS) and hospital anxiety and depression scale). The prediction of acute post-TKA pain was assessed by univariate analysis, logistic regressions and ROC curves. RESULTS: Reduced PPT on the arm and increased PCS were predictive variables for moderate/severe post-TKA pain 24 h after surgery (P = 0.007 and P = 0.026, respectively, R-squared 0.21) in the logistic regression model. Odds ratios were 0.67 for a 50 kPa increased PPT and 1.36 for a 5 point increase in PCS. A predictive model with cut-off values of PPT ≤ 245 kPa and PCS≥ 8 point had a sensitivity of 71.4 and a specificity of 62.5. CONCLUSION: Pre-operative widespread pressure pain hypersensitivity and pain catastrophizing are predictive of moderate severe post-TKA pain. If validated in a larger population, the clinically applicable tests should be considered in future interventions aiming to minimize post-operative pain in high-risk patients.

Association between sensory dysfunction and pain 1 week after breast cancer surgery: a psychophysical study.

BACKGROUND: Breast cancer patients treated with axillary lymph node dissection (ALND) have a higher risk of both acute and persistent pain than those treated with sentinel lymph node biopsy (SLNB). This could be attributed to a higher risk of nerve injury with ALND. We hypothesized that (1) pain patients have more pronounced sensory dysfunction than pain-free patients, (2) ALND have more sensory dysfunction and pain than SLNB patients and (3) patients with preserved intercostobrachial nerve (ICBN) preservation have less sensory dysfunction compared to a sectioned ICBN. METHODS: Twenty-seven patients treated with ALND and 27 with SLNB examined with a standardized Quantitative Sensory Testing (QST) protocol, including sensory mapping, mechanical and thermal thresholds, as well as recording intraoperative ICBN handling and pain status 1 week post-operative. RESULTS: The area of cold hypoaesthesia was significantly associated with movement-related pain (P = 0.004), with a similar tendency for warmth (P = 0.018) and brush (P = 0.030) hypoaesthesia areas. 14 (26%) of the patients had moderate/severe pain at rest and 13 (24%) during movement without differences between ALND and SLNB, but ALND was associated with more sensory dysfunction than SLNB. Patients with sectioned ICBN reported lower pain intensity than those with preserved ICBN (P = 0.005), but without differences in sensory dysfunction. CONCLUSION: Pain was increased in patients having larger areas of hypoaesthesia and reduced in patients where ICBN-section was done. Sensory dysfunction was related to extent of axillary surgery, but not with ICBN handling. Our data suggest that acute pain after breast cancer surgery may be related to nerve injury.

Chronic pre-operative opioid use and acute pain after fast-track total knee arthroplasty.

BACKGROUND: Pre-operative opioid use has been suggested to increase post-operative pain and opioid consumption after total knee arthroplasty (TKA), but previous studies are either retrospective or inhomogeneous with regard to surgical procedures or control of analgesic regimes, or with few opioid-treated patients, hindering firm conclusions. METHODS: In a prospective observational study, we investigated the effect of > 4 weeks pre-operative opioid use [none vs. low dose (< 30 mg morphine equivalents (eq.)) vs. high dose (> 30 mg morphine eq.] in patients scheduled for primary, unilateral TKA. All patients had well-defined multimodal opioid-sparring perioperative analgesic therapy, and continued any pre-operative opioid medication. The primary outcome was differences between groups in pain at rest and during walk for the first 6 post-operative days. RESULTS: Among 123 patients included, 115 were available for final analysis (93% follow-up rate). Post-operative pain during walk was significantly increased in both opioid-treated groups vs. non-opioid-treated patients (P < 0.009). Secondary analysis of combining all pre-operatively opioid-treated patients vs. opioid-free patients, showed significantly increased pain at rest and walk and increased post-operative opioid requirement - excluding pre-operative dosage - during the first post-operative week in opioid-treated patients (P = 0.001 and P = 0.007, respectively). CONCLUSION: Pre-operative opioid use increases the risk for post-operative pain at rest and walk, and increased opioid consumption after TKA.

Challenges in postdischarge function and recovery: the case of fast-track hip and knee arthroplasty.

This narrative review updates the recent advances in our understanding of the multifactorial pathogenesis for reduced postdischarge physical and cognitive function after fast-track surgery, using total hip and knee arthroplasty as surgical models. Relevant factors discussed include the surgical stress responses and potential methods for controlling postsurgical inflammation, pain, and cognitive dysfunction. The continuation of moderate to severe pain in up to 30% of patients for 2-4 weeks calls for better understanding of the underlying mechanisms and development of effective multimodal opioid-sparing analgesic regimens. The need for the development of effective physiotherapy programmes on a patient-specific basis is discussed, along with the need for optimal assessment of postoperative function to guide rehabilitation. Other relevant factors discussed include the role of orthostatic intolerance, sleep disturbances, and blood management, and specific patient populations at risk for adverse outcomes, including psychiatric disorders, to identify and guide future interventions for optimizing functional postdischarge outcomes after fast-track surgery.

Referred pain and cutaneous responses from deep tissue electrical pain stimulation in the groin.

BACKGROUND: Persistent postherniotomy pain is located around the scar and external inguinal ring and is often described as deep rather than cutaneous, with frequent complaints of pain in adjacent areas. Whether this pain is due to local pathology or referred/projected pain is unknown, hindering mechanism-based treatment. METHODS: Deep tissue electrical pain stimulation by needle electrodes in the right groin (rectus muscle, ilioinguinal/iliohypogastric nerve and perispermatic cord) was combined with assessment of referred/projected pain and the cutaneous heat pain threshold (HPT) at three prespecified areas (both groins and the lower right arm) in 19 healthy subjects. The assessment was repeated 10 days later to assess the reproducibility of individual responses. RESULTS: Deep electrical stimulation elicited pain at the stimulation site in all subjects, and in 15 subjects, pain from areas outside the stimulation area was reported, with 90-100% having the same response on both days, depending on the location. Deep pain stimulation significantly increased the cutaneous HPT (P<0.014). Individual HPT responses before and during deep electrical pain stimulation were significantly correlated (ρ>0.474, P≤0.040) at the two test days for the majority of test areas. CONCLUSION: Our results corroborate a systematic relationship between deep pain and changes in cutaneous nociception. The individual referred/projected pain patterns and cutaneous responses are variable, but reproducible, supporting individual differences in anatomy and sensory processing. Future studies investigating the responses to deep tissue electrical stimulation in persistent postherniotomy pain patients may advance our understanding of underlying pathophysiological mechanisms and strategies for treatment and prevention. TRIAL REGISTRY NUMBERS: ClinicalTrials.gov (NCT01701427).

Intercostobrachial nerve handling and pain after axillary lymph node dissection for breast cancer.

BACKGROUND: Moderate to severe pain in the first week after axillary lymph node dissection (ALND) for breast cancer is experienced by approximately 50% of the patients. Damage to the intercostobrachial nerve (ICBN) has been proposed as a risk factor for the development of persistent pain following breast cancer surgery but with limited information on acute post-operative pain. The aim of the present study was to examine the influence of ICBN handling on pain during the first week after ALND. METHODS: The study was part of a larger prospective cohort study on persistent pain after breast cancer treatment. Pain and sensory disturbances were assessed pre-operatively, within the first 72 h post-operatively and a week after surgery. Intraoperative handling of the nerve was recorded by the surgeon as preserved, partially preserved or sectioned. RESULTS: One hundred forty-one patients were treated with ALND level I + II, and the ICBN could be identified in 125 (89%) patients. Of the 17 not identified, eight were stated as without any sign of the nerve and were included in analysis as sectioned. Thus, the analysis included 133 patients in which 45 (34%) of these the ICBN was preserved, 39 (29%) partially preserved and 49 (37%) sectioned. At 1 week after surgery, 104 patients (78%) reported pain, whereas 35 (26%) reported moderate to severe pain. There was no difference between the ICBN groups in pain scores or sensory disturbances measured pre-operatively compared to 1 week post-operatively. CONCLUSION: The type of ICBN handling during ALND may not influence acute post-operative pain in the first week after surgery.

Assessment of deep tissue hyperalgesia in the groin - a method comparison of electrical vs. pressure stimulation.

BACKGROUND: Deep pain complaints are more frequent than cutaneous in post-surgical patients, and a prevalent finding in quantitative sensory testing studies. However, the preferred assessment method - pressure algometry - is indirect and tissue unspecific, hindering advances in treatment and preventive strategies. Thus, there is a need for development of methods with direct stimulation of suspected hyperalgesic tissues to identify the peripheral origin of nociceptive input. METHODS: We compared the reliability of an ultrasound-guided needle stimulation protocol of electrical detection and pain thresholds to pressure algometry, by performing identical test-retest sequences 10 days apart, in deep tissues in the groin region. Electrical stimulation was performed by five up-and-down staircase series of single impulses of 0.04 ms duration, starting from 0 mA in increments of 0.2 mA until a threshold was reached and descending until sensation was lost. Method reliability was assessed by Bland-Altman plots, descriptive statistics, coefficients of variance and intraclass correlation coefficients. RESULTS: The electrical stimulation method was comparable to pressure algometry regarding 10 days test-retest repeatability, but with superior same-day reliability for electrical stimulation (P < 0.05). Between-subject variance rather than within-subject variance was the main source for test variation. There were no systematic differences in electrical thresholds across tissues and locations (P > 0.05). CONCLUSION: The presented tissue-specific direct deep tissue electrical stimulation technique has equal or superior reliability compared with the indirect tissue-unspecific stimulation by pressure algometry. This method may facilitate advances in mechanism based preventive and treatment strategies in acute and chronic post-surgical pain states.

Does nerve identification during open inguinal herniorrhaphy reduce the risk of nerve damage and persistent pain?

PURPOSE: Nerve identification during open inguinal hernia herniorrhaphy has been suggested as one of the factors that may reduce the risk of development of persistent postherniorrhaphy pain. In this prospective study, we evaluated whether intraoperative inguinal nerve identification influenced the risk of development of persistent postherniorrhaphy pain, sensory dysfunction in the groin and functional ability score after open hernia repair. METHODS: A total of 244 men with a primary inguinal hernia underwent open Lichtenstein repair in a high-volume hernia surgery centre, where information on inguinal nerve identification was registered during operation. Before the operation and 6 months postoperatively, functional pain-related impairment was assessed with Activities Assessment Scale and pain intensity scores with Numeric Rating Scale (NRS 0-10). Quantitative sensory testing in the groin was performed before operation and 6 months postoperatively, in order to investigate intraoperative inguinal nerve damage. RESULTS: The intraoperative nerve identification rates for the iliohypogastric, ilioinguinal and genitofemoral nerves were 94.7, 97.5 and 21.3 %, respectively. Thirty-nine patients (16.0 %) had substantial pain-related functional impairment at 6 months follow-up. There was no difference in risk of development of substantial pain-related functional impairment in patients with identification compared with non-identification of the iliohypogastric nerve (P = 1.0), the ilioinguinal nerve (P = 0.59), the genitofemoral nerve (P = 0.40) or all nerves (P = 0.52). There were no differences in regard to sensory loss in the groin area or in regard to improvement in functional outcome following surgery, between patients with and without nerve identification. CONCLUSIONS: Although intraoperative inguinal nerve identification should be aimed at, other factors may contribute to the risk of nerve damage and persistent pain after open groin hernia repair.