David C. Chen

Operative management of refractory neuropathic inguinodynia by a laparoscopic retroperitoneal approach.

IMPORTANCE With the technical success of tension-free inguinal herniorrhaphy, chronic groin pain has far surpassed recurrence as the most common long-term complication. OBJECTIVE To evaluate laparoscopic triple neurectomy of the ilioinguinal, iliohypogastric, and genitofemoral nerve trunks in the retroperitoneal lumbar plexus for treatment of refractory inguinodynia. DESIGN Prospective study. SETTING University hernia center. PARTICIPANTS Twenty consecutive patients with chronic inguinodynia (14 male; mean age, 46 years; all failing pain management; prior neurectomy in 4 patients) and follow-up to 180 days (minimum, 90 days). MAIN OUTCOMES AND MEASURES Groin pain (Numeric Rating Scale score), dermatomal mapping, hernia recurrence, histologic confirmation, and complications. RESULTS There were no intraoperative complications. All patients had histologic confirmation of neurectomy and clinical confirmation with dermatomal mapping. Mean numeric pain scores were significantly decreased (baseline score, 7.8) on postoperative days 1 (score, 2.9; P < .001), 7 (score, 2.2; P < .001), 30 (score, 1.7; P < .001), and 90 (score, 1.9; P < .001). Narcotic dependence decreased and activity level increased. Five patients reported transient hypersensitivity consistent with deafferentation. All had numbness in the distribution of neurectomy without complaint. Four had residual meshoma pain, with 2 undergoing subsequent reoperation to remove mesh. Orchialgia was not improved. CONCLUSIONS AND RELEVANCE This represents the largest series of laparoscopic retroperitoneal triple neurectomies for treatment of inguinodynia. The rate of successful intervention was better than reported for standard triple neurectomy and open extended triple neurectomy. The procedure allows access proximal to all potential sites of peripheral neuropathy and overcomes many of the limitations of open triple neurectomy. In the absence of recurrence or meshoma, it is the preferred technique for definitive management of chronic inguinal neuralgia.

An international consensus algorithm for management of chronic postoperative inguinal pain

PurposeTension-free mesh repair of inguinal hernia has led to uniformly low recurrence rates. Morbidity associated with this operation is mainly related to chronic pain. No consensus guidelines exist for the management of this condition. The goal of this study is to design an expert-based algorithm for diagnostic and therapeutic management of chronic inguinal postoperative pain (CPIP).MethodsA group of surgeons considered experts on inguinal hernia surgery was solicited to develop the algorithm. Consensus regarding each step of an algorithm proposed by the authors was sought by means of the Delphi method leading to a revised expert-based algorithm.ResultsWith the input of 28 international experts, an algorithm for a stepwise approach for management of CPIP was created. 26 participants accepted the final algorithm as a consensus model. One participant could not agree with the final concept. One expert did not respond during the final phase.ConclusionThere is a need for guidelines with regard to management of CPIP. This algorithm can serve as a guide with regard to the diagnosis, management, and treatment of these patients and improve clinical outcomes. If an expectative phase of a few months has passed without any amelioration of CPIP, a multidisciplinary approach is indicated and a pain management team should be consulted. Pharmacologic, behavioral, and interventional modalities including nerve blocks are essential. If conservative measures fail and surgery is considered, triple neurectomy, correction for recurrence with or without neurectomy, and meshoma removal if indicated should be performed. Surgeons less experienced with remedial operations for CPIP should not hesitate to refer their patients to dedicated hernia surgeons.

Surgical Treatment of Chronic Groin and Testicular Pain after Laparoscopic and Open Preperitoneal Inguinal Hernia Repair

BACKGROUND Standard triple neurectomy does not address inguinodynia secondary to neuropathy of the genitofemoral nerve and the preperitoneal segment of its genital branch seen after inguinal hernia repair performed laparoscopically or in open preperitoneal fashion. STUDY DESIGN Standard triple neurectomy was extended to include the genitofemoral nerve. Sixteen patients with chronic groin pain after laparoscopic and open preperitoneal inguinal hernia repair underwent operative triple neurectomy, with resection of the main trunk of the genitofemoral nerve in the retroperitoneum over the psoas muscle. All patients had previously undergone unsuccessful extensive nonsurgical pain management. RESULTS Fourteen of 16 patients had significant improvement of their pain, as evidenced by a decrease in subjectively reported postoperative pain levels as compared with their preoperative baseline, a decrease or complete elimination of daily narcotic dependence, and return to baseline activities of daily living and work. One of the nonresponder patients underwent a previous open prostatectomy, and exposure of the genitofemoral nerve was not possible due to scarring from the prostatectomy. The other nonresponder patient continues to experience subjective pain equivalent to preoperative levels due to the sensation of firmness and incisional pain that arose in the setting of a postoperative wound infection. He does, however, report that his pain is of different character and quality from his preneurectomy pain and is primarily centered around the incision. His follow-up has not been long enough to determine if his symptoms will improve as his incision and scar remodel. CONCLUSIONS Extension of the standard triple neurectomy to include the genitofemoral nerve for treatment of inguinodynia after open and laparoscopic preperitoneal mesh repair is a safe and effective procedure.

Pain control following inguinal herniorrhaphy: current perspectives

Inguinal hernia repair is one of the most common surgeries performed worldwide. With the success of modern hernia repair techniques, recurrence rates have significantly declined, with a lower incidence than the development of chronic postherniorrhaphy inguinal pain (CPIP). The avoidance of CPIP is arguably the most important clinical outcome and has the greatest impact on patient satisfaction, health care utilization, societal cost, and quality of life. The etiology of CPIP is multifactorial, with overlapping neuropathic and nociceptive components contributing to this complex syndrome. Treatment is often challenging, and no definitive treatment algorithm exists. Multidisciplinary management of this complex problem improves outcomes, as treatment must be individualized. Current medical, pharmacologic, interventional, and surgical management strategies are reviewed.

Comparison of Polyester Scaffolds for Bioengineered Intestinal Mucosa

Introduction: Biodegradable polyester scaffolds have proven useful for growing neointestinal tissue equivalents both in vitro and in vivo. These scaffolds allow cells to attach and grow in a 3-dimensional space while nutrient flow is maintained throughout the matrix. The purpose of this study was to evaluate different biopolymer constructs and to determine mucosal engraftment rates and mucosal morphology. Hypothesis: We hypothesized that different biopolymer constructs may vary in their ability to provide a good scaffolding onto which intestinal stem cell organoids may be engrafted. Study Design: Eight different microporous biodegradable polymer tubes composed of polyglycolic acid (PGA), polylactic acid, or a combination of both, using different fabrication techniques were seeded with intestinal stem cell clusters obtained from neonatal rats. Three different seeded polymer constructs were subsequently placed into the omentum of syngeneic adult recipient rats (n = 8). Neointestinal grafts were harvested 4 weeks after implantation. Polymers were microscopically evaluated for the presence of mucosal growth, morphology, scar formation and residual polymer. Results: Mucosal engraftment was observed in 7 out of 8 of the polymer constructs. A maximal surface area engraftment of 36% (range 5–36%) was seen on nonwoven, randomly entangled, small fiber PGA mesh coated with aerosolized 5% poly-L-lactic acid. Villous and crypt development, morphology and created surface area were best on PGA nonwoven mesh constructs treated with poly-L-lactic acid. Electrospun microfiber PGA had poor overall engraftment with little or no crypt or villous formation. Conclusion: Intestinal organoids can be engrafted onto biodegradable polyester scaffoldings with restitution of an intestinal mucosal layer. Variability in polymer composition, processing techniques and material properties (fiber size, luminal dimensions and pore size) affect engraftment success. Future material refinements should lead to improvements in the development of a tissue-engineered intestine.

Myocardial Perfusion Magnetic Resonance Imaging Using Sliding-Window Conjugate-Gradient Highly Constrained Back-Projection Reconstruction for Detection of Coronary Artery Disease

Myocardial perfusion magnetic resonance imaging (MRI) with sliding-window conjugate-gradient highly constrained back-projection reconstruction (SW-CG-HYPR) allows whole left ventricular coverage, improved temporal and spatial resolution and signal/noise ratio, and reduced cardiac motion-related image artifacts. The accuracy of this technique for detecting coronary artery disease (CAD) has not been determined in a large number of patients. We prospectively evaluated the diagnostic performance of myocardial perfusion MRI with SW-CG-HYPR in patients with suspected CAD. A total of 50 consecutive patients who were scheduled for coronary angiography with suspected CAD underwent myocardial perfusion MRI with SW-CG-HYPR at 3.0 T. The perfusion defects were interpreted qualitatively by 2 blinded observers and were correlated with x-ray angiographic stenoses ≥50%. The prevalence of CAD was 56%. In the per-patient analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SW-CG-HYPR was 96% (95% confidence interval 82% to 100%), 82% (95% confidence interval 60% to 95%), 87% (95% confidence interval 70% to 96%), 95% (95% confidence interval 74% to100%), and 90% (95% confidence interval 82% to 98%), respectively. In the per-vessel analysis, the corresponding values were 98% (95% confidence interval 91% to 100%), 89% (95% confidence interval 80% to 94%), 86% (95% confidence interval 76% to 93%), 99% (95% confidence interval 93% to 100%), and 93% (95% confidence interval 89% to 97%), respectively. In conclusion, myocardial perfusion MRI using SW-CG-HYPR allows whole left ventricular coverage and high resolution and has high diagnostic accuracy in patients with suspected CAD.

Waveguide photonic devices made from thermally crosslinked second-order nonlinear optical polymers

A number of new thermally crosslinkable second-order nonlinear optical polymers have been developed and characterized. These polymers are designed for stable nonlinear optical activities since both ends of the rod-like chromophores are locked into a polymer matrix by covalent bonds. Sizable nonlinearities were measured in these polymers and the thermal stability of both main chain and side chain polymers were improved significantly by thermally induced crosslinking. These thermosetting polymers, with the chromophores either included in the main chain or as side chain pendants, have been used in a number of device applications. Waveguide structures can be defined in these polymers by reactive ion etching or ultraviolet bleaching. Thin film integrated optical devices, such as high frequency electro-optic modulators and birefringent directional couplers have been fabricated with reactive ion etching and photo bleaching methods. Waveguide fabrication techniques for multi-layer structures are discussed in detail.

Prevention of inguinodynia: the need for continuous refinement and quality improvement in inguinal hernia repair.

Dear Editors, It was with great interest that we read the manuscript Mesh fixation at laparoscopic inguinal hernia repair: a meta-analysis comparing fibrin glue to tack fixation [1]. While there have been several studies, randomized controlled trials (RCTs), reviews, and meta-analyses comparing these fixation methods, the authors have provided a methodologically sound analysis of the available studies to date, commendably choosing to focus on the outcome of chronic pain. The success of modern herniorrhaphy techniques and the use of prosthetic materials have dramatically reduced recurrence rates, and chronic pain exceeds recurrence as the more frequent complication. Quality of life and avoidance of chronic pain have become important metrics of successful surgery. Inguinodynia has been a recognized complication with all techniques of hernia repair and long preceded meshbased techniques. [2, 3] While there is a statistical advantage of laparoscopic repair with regards to acute pain, direct comparisons between open and laparoscopic repair regarding chronic pain are difficult because the definitions and technique vary amongst studies. The wide variation is apparent, even within this meta-analysis of laparoscopic repairs where the five included trials report rates of chronic pain ranging from 0 to 24 % [1]. The recently published 2014 update to the European Hernia Society (EHS) guidelines reaffirms that there is no difference in the incidence of significant chronic pain between open and laparoscopic repair. [4] Remedial surgery for neuropathic inguinodynia after preperitoneal repair is more challenging than with anterior repair and requires proximal access to these nerves via retroperitoneal neurectomy. [5–7] Proper technique and respect for neuroanatomy with each chosen method of repair is critical to improving outcomes and preventing inguinodynia. The important developments by Nyhus, Read, Stoppa, Wantz, Rives, Shumpelick, and others have helped to define and utilize the preperitoneal anatomy for effective hernia repairs. Laparoscopic totally extraperitoneal (TEP) and transabdominal preperitoneal (TAPP) approaches have made this compartmental anatomy ubiquitous for most hernia surgeons. However, in-depth understanding of the neuroanatomy of this compartment is needed to prevent neuralgia, orchialgia, dysejaculation, recurrence, and meshoma. [8] Causes of chronic pain can be nociceptive or neuropathic in origin and there is often overlap between the two, making diagnosis and treatment challenging. The most common causative mechanisms with laparoscopic inguinal hernia repair include neuropathy from direct contact with mesh, meshoma pain from folding of the mesh, and direct nerve injury (dissection, thermal injury, fixation). [5, 6] Read [9] and Mirilas et al. [10] have helped to delineate the surgical anatomy of the preperitoneal space, confirming the presence of two compartments behind the transversalis fascia separated by a membranous layer. [8–10] The visceral compartment medially contains the bladder, ureter, and prostate and laterally contains the vas deferens ensheathed by this membranous layer. The parietal compartment contains the genitofemoral trunk and its genital and femoral branches and the lateral femoral cutaneous nerve within the classically described ‘trapezoid of pain’. The ilioinguinal and iliohypogastric nerves travel in the retroperitoneum and exit cephalad and lateral to most preperitoneal repairs. [7, 10] Unlike the nerves in the D. C. Chen P. K. Amid (&) Department of Surgery, Lichtenstein Amid Hernia Clinic at UCLA, UCLA David Geffen School of Medicine, Santa Monica, CA, USA e-mail: pamid@mednet.ucla.edu

Groin Pain After Inguinal Hernia Repair

Quality of life and avoidance of chronic postoperative inguinal pain (CPIP) are now primary outcomes of elective inguinal herniorrhaphy because of the success of tension-free mesh-based repairs. Multidisciplinary approach with a pain management team is indicated if several months of expectantmanagement of CPIP do not result in amelioration of symptoms. Conservative treatment with topical, pharmacologic, behavioral, and expectant measures is advocated in all patients. Triple neurectomy is the recommended surgical treatment of neuropathic inguinal pain refractory to conservative measures. Reoperation for CPIP is best performed by experienced herniologists; less experienced clinicians should refer patients with CPIP who fail conservative management to a multidisciplinary team.

A real-time mobile web-based module promotes bidirectional feedback and improves evaluations of the surgery clerkship

BACKGROUND We implemented a real-time mobile web-based reporting module for students in our surgery clerkship and evaluated its effect on student satisfaction and perceived abuse. METHODS Third-year medical students in the surgery clerkship received surveys regarding intimidation, perceived abuse, satisfaction with clerkship resources, and interest in a surgical career. Survey data were analyzed to assess differences after implementing the mobile reporting system and to identify independent predictors of perceived abuse. RESULTS With the reporting module, students perceived less intimidation by residents (P < .001) and by faculty (P = .008), greater satisfaction reporting feedback (P < .001), and greater interest in surgical careers (P = .003). Perceived abuse decreased without reaching statistical significance (P = .331). High ratings of intimidation by faculty independently predicted perceived abuse (odds ratio = 1.3), and satisfaction with anonymous reporting was a negative predictor (odds ratio = .2). CONCLUSIONS A mobile web-based system for real-time reporting fosters open communication and bidirectional feedback and promotes greater satisfaction with the surgery clerkship and interest in a surgical career.