Abdominal Wall Pain:​ Clinical Evaluation, Differential Diagnosis, and Treatment Brian Shian, MD, and Scott T. Larson, MD, University of Iowa Carver College of Medicine, Iowa City, Iowa

Abdominal wall pain is often mistaken for intra-abdominal visceral pain, resulting in expensive and unnecessary laboratory tests, imaging studies, consultations, and invasive procedures. Those evaluations generally are nondiagnostic, and lingering pain can become frustrating to the patient and clinician. Common causes of abdominal wall pain include nerve entrapment, , and surgical or procedural complications. Anterior cutaneous nerve entrapment syndrome is the most common and frequently missed type of abdominal wall pain. This condition typically presents with acute or chronic localized pain at the lat- eral edge of the rectus abdominis that worsens with position changes or increased abdominal muscle tension. Abdominal wall pain should be suspected in patients with no symptoms or signs of visceral etiology and a localized small tender spot. A positive Carnett test, in which tenderness stays the same or worsens when the patient tenses the abdominal muscles, suggests abdom- inal wall pain. A local anesthetic injection can confirm the diagnosis when there is 50% postprocedural pain improvement. Point-of-care ultrasonography may help rule out other abdominal wall pathologies and guide injections. The management of abdominal wall pain depends on the etiology. Reassurance and patient education can be helpful. Local injection with an anesthetic and a corticosteroid is an effective treatment for anterior cutaneous nerve entrapment syndrome, with an over- all response rate of 70% to 99%. For refractory cases that require more than two injections, surgical neurectomy generally resolves the pain. (Am Fam Physician. 2018;​98(7):​429-436. Copyright © 2018 American Academy of Family Physicians.)

Pain originating from the abdominal wall has been Abdominal wall pain is an umbrella term that comprises described for nearly 100 years 1 but did not receive much many etiologies, the most common of which is benign nerve attention until 1926, when a simple bedside test was pro- entrapment. Because of physicians’ unfamiliarity with posed.2 Case reports in the early 1970s suggested that nerve abdominal wall pain and concern about the consequences of entrapment could be the cause of abdominal wall pain and missing serious pathology, evaluation is often misdirected was able to be successfully treated with local injections.3,4 toward costly and unnecessary laboratory tests, advanced More recently, the consensus has been that abdominal wall imaging studies, consultations, and frequent clinic visits. pain is commonly unrecognized, overlooked, underdiag- Patients may be exposed to unwarranted invasive proce- nosed, and understudied.5-11 dures such as endoscopy, , or cholecystectomy. The prevalence of abdominal wall pain in the general These procedures have a high cost: ​one study calculated that population and primary care settings is not known, but it the typical patient had abdominal wall pain for 25 months ranges from 5% to 67% in patients referred to subspecial- before diagnosis, with an annual direct health care cost of ists.12-14 A study of 100 consecutive patients referred to a more than $1,100.12 This highlights the importance of early pain clinic by gastroenterologists for chronic abdominal consideration of abdominal wall pain. The critical task for pain management found that 43 had abdominal wall pain, clinicians is to distinguish benign etiologies from more and that many were initially misdiagnosed with functional serious intra- or extra-abdominal causes. abdominal pain, irritable bowel syndrome, or a psychiatric This article updates a previousAmerican Family Physi- disorder.13 cian article on abdominal wall pain with emerging data on point-of-care ultrasonography and surgical intervention.8 Additional content at https://​www.aafp.org/afp/2018/ Applied Anterior Abdominal Wall Anatomy 1001/p429.html. Understanding the anatomy of the anterior abdominal wall CME This clinical content conforms to AAFP criteria for continuing medical education (CME). See CME Quiz on will aid clinicians in diagnosing and treating abdominal page 417. wall pain. There are five pairs of muscles in the anterior Author disclosure: No relevant financial affiliations. abdominal wall (Figure 1). Along the midline, the rectus abdominis can cause localized pain on the xyphoid process

Downloaded from the American Family Physician website at www.aafp.org/afp. Copyright © 2018 American Academy of Family Physicians. For the private, noncom- Downloaded from the◆ American Family Physician website at www.aafp.org/afp. Copyright © 2018 American Academy of Family Physicians. For the private, noncom 429- mercial use of one individual user of the website. All other rights reserved. Contact [email protected] for copyright questions and/or permission requests. Octobermercial 1, use 2018 of one Volume individual 98, user Number of the 7 website. All other rightswww.aafp.org/afp reserved. Contact [email protected] for copyright questionsAmerican and/or Family permission Physician requests. SORT:​ KEY RECOMMENDATIONS FOR PRACTICE

Evidence Clinical recommendation rating References

Anterior cutaneous nerve entrapment C 4, 16, 18, 21, 38 posterior quarter inferior to the arcuate line), syndrome should be suspected in the inguinal inferiorly, the linea semi- patients with a localized small tender spot at the lateral edge of the rectus lunaris lateral to the rectus abdominis, and the 15 abdominis. at the midline. These aponeuroses, as well as the navel and any surgical incision sites, The Carnett test is useful to support the C 2, 28, 32 are areas prone to hernia formation. diagnosis of abdominal wall pain. The nerves of the anterior abdominal wall Local anesthetic injection with or without B 10, 33-36 are the ventral rami of the T6-L1 spinal nerves corticosteroids can diagnose and treat (Figure 2). It was originally thought that the abdominal wall pain caused by nerve entrapment. terminal branches of the T7-T12 ventral rami enter the lateral posterior rectus abdominis at a A = consistent, good-quality patient-oriented evidence;​ B = inconsistent or limited- 90-degree angle through a fibrous neurovascu- quality patient-oriented evidence;​ C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT lar channel, progressing anteriorly through the evidence rating system, go to https://www.aafp.org​ /afpsort. muscle and anterior to become the anterior cutaneous nerves of the . Once those nerves reach the overlying aponeurosis, the nerves again change course at 90-degree angles FIGURE 1 beneath the .16 A recent study indicates that their anatomy is far more complex.17 The L1 nerve bifurcates into the iliohypogastric and ilioingui- nal nerves; ​the iliohypogastric nerve pierces the external oblique aponeurosis superior to the superficial inguinal ring, whereas the ilioingui- Rectus nal nerve passes through the to abdominis 15 Rectus emerge through the superficial inguinal ring. sheath Linea Etiologies and Differential Diagnoses semilunaris Transversus abdominis Abdominal wall pain can originate locally. Less commonly, it can be referred from intra-abdom- Internal oblique inal pathology, intrathoracic visceral pathology, or thoracic spinal radiculopathy. Linea alba External oblique The most common cause of abdominal wall pain is nerve entrapment at the lateral border of Pyramidalis the rectus muscle; ​this is known as anterior cuta- neous nerve entrapment syndrome.4,16 It is caused Inguinal by compression of an anterior cutaneous nerve as ligament it courses through the abdominal wall muscula- ture and aponeuroses.16 Intra- or extra-abdominal pressure or scar formation causes traction on the nerve, leading to nerve irritation and, potentially, Muscles of the abdominal wall. nerve ischemia.4,18 Ilioinguinal–iliohypogastric

Illustration by Christy Krames nerve entrapment is another common cause of lower abdominal pain in patients with a history of lower abdominal surgery, particularly inguinal herniorrhaphy, , and procedures superiorly or in the pubic area inferiorly. The pyramida- incorporating a Pfannenstiel incision.19 Diabetic neuropa- lis can also cause pubic area pain. The lateral abdominal thy, thoracic spine radiculopathy, and postherpetic neural- wall is composed of—from superficial to deep—the exter- gia are less common causes of abdominal wall pain. nal oblique, internal oblique, and transverse abdominis Sports are a common cause of groin pain in ath- muscles. Their aponeuroses fuse together, forming the rec- letes, although the term is a misnomer because there is tus sheath that encloses the rectus abdominis (except the no classical herniation of soft tissue. Pain is thought to be

430 American Family Physician www.aafp.org/afp Volume 98, Number 7 ◆ October 1, 2018 ABDOMINAL WALL PAIN

True hernias, either incisional or sponta- FIGURE 2 neous, may cause abdominal wall pain without noticeable bulging or obstructive symptoms. Incisional hernias can occur wherever there is T3 an incision. Nonincisional hernias tend to be T4 localized at the epigastric and umbilical areas in

T5 Anterior the midline or laterally in the groin or around cutaneous the linea semilunaris. Spigelian hernias, which T6 branches Ventral rami are rare defects in the transversus aponeurosis T7 Lateral of T6-T12 occurring at the junction of the rectus abdom- T8 cutaneous inis and linea semilunaris, often occur at or branches T9 inferior to the arcuate line because the posterior T10 rectus sheath is lacking in this area. Spigelian hernias can be difficult to clinically distinguish T11 lliohypogastric nerve (L1) from anterior cutaneous nerve entrapment syn- T12 llioinguinal nerve (L1) drome because of the location, although ultra- sonography may help.21 L1 Other less common benign causes of abdom- inal wall pain include abdominal wall muscle strain, abdominal wall endometriosis, and slip- Nerves of the abdominal wall. ping rib syndrome;​ less common but poten- tially more serious causes include rectus sheath Illustration by Christy Krames hematoma, abdominal wall infection, and intra-abdominal pathology with adhesion to the abdominal wall.22-27 An inflamed appendix with caused by an imbalance between the strength of adductor adhesion to the abdominal wall may cause localized pain and abdominal wall muscles and partial weakness of the but is generally associated with systemic symptoms.28 posterior abdominal wall. There is evidence implicating The differential diagnosis of abdominal wall pain also nerve entrapment in some cases of sports hernias.20 includes intra-abdominal visceral etiology (Table 1)

TABLE 1

Clinical Findings That Differentiate Abdominal Wall Pain from Intra-abdominal Visceral Pain Clinical finding Intra-abdominal visceral pain Abdominal wall pain

Advanced imaging findings Often positive Usually unremarkable

Carnett test Negative Positive

Constitutional symptoms Anorexia, chills, fever, weight loss Typically absent

Gastrointestinal or genitouri- Altered bowel habits, dysuria, frequent urination, Typically absent nary symptoms gastrointestinal bleeding, jaundice, nausea, vagi- nal bleeding or discharge, vomiting

Laboratory findings Elevated white blood cell count, inflammatory Usually within normal limits markers, or serum lactate level

Pain characteristics Aggravated/relieved by eating or defecation;​ Unrelated to meals or bowel function; ​con- peristaltic pain stant or fluctuating, nonperistaltic

Sex predominance None Females

Tender spot Location depends on underlying pathology;​ Clearly identifiable superficial tender area relatively vague < 2 cm, typically near the rectus abdominis

October 1, 2018 ◆ Volume 98, Number 7 www.aafp.org/afp American Family Physician 431 ABDOMINAL WALL PAIN TABLE 2

Etiologies and Differential Diagnosis of Abdominal Wall Pain Condition Clinical features

Abdominal wall Cyclic abdominal pain, history of laparotomy;​ mass often and other rare causes, such as endometriosis 22,23 can be localized xiphodynia or adiposis dolorosa 7,8,16,20,22-26,28-31 Abdominal wall mus- Usually caused by traumatic event;​ occurs mainly in athletes (Table 2). cle injury Evaluation Adiposis dolorosa Obesity with multiple painful lipomas (Dercum disease, A history and targeted physical exam- Anders disease) ination, potentially complemented Anterior cutaneous Localized (< 2 cm) unilateral sharp pain, acute or chronic; ​ with local anesthetic injection or ultra- nerve entrapment retrograde radiation horizontally in the upper abdomen and sonography, generally can promptly syndrome16 obliquely downward in the lower abdomen (Valleix phe- and accurately identify the abdominal nomenon);​ worsening with abdominal muscle movement;​ wall as the source of pain. more prevalent in females Desmoid tumor 8 Dysplastic tumor of connective tissue occurring in young HISTORY patients (more often in females) Abdominal wall pain is typically pro- Diabetic thoracic Severe, chronic abdominal pain in patients with diabetes;​ voked by physical movement, such polyradiculopathy 29 may affect sensory, motor, and autonomic functions;​ asso- ciated with other diabetic complications, weight loss, and as lifting, bending, laughing, strain- paretic abdominal wall protrusion ing, and twisting. Therefore, a history regarding precipitating and associated Hernia (epigastric, Protuberance in abdominal wall that usually decreases in hypogastric, umbilical, size when patient is supine;​ localized to a natural or iatro- factors is crucial in making the diag- inguinal, incisional, genic weak spot on the abdominal wall nosis. Questions about gastrointesti- and Spigelian)8 nal, genitourinary, or constitutional Herpes zoster Pain and hyperesthesia preceding vesicular rash in dermato- symptoms are vital for ruling out mal distribution intra-abdominal etiology. It is also Idiopathic or myofas- Localized abdominal wall pain with unclear etiology important to ask about a history of cial pain syndrome abdominal surgery, injury, trauma,

Ilioinguinal nerve History of surgery with a Pfannenstiel incision;​ iliac fossa diabetes mellitus, or back problems entrapment pain radiating to the groin, proximal scrotum, labia majora, to rule out neuropathic causes. The syndrome 7 upper inner thigh, and back;​ altered sensory perception in patient’s ability to localize pain with affected areas and a trigger point medial and inferior to the a fingertip is an element of the history anterosuperior iliac spine that is highly suggestive of abdominal Rectus sheath Abdominal wall pain associated with a mass and decrease wall pain.11 Patients with abdominal hematoma26 in hemoglobin level;​ commonly associated with , intra-abdominal procedure, anticoagulation, or cough wall pain often have comorbid obe- sity.12 Validated screening tools can Slipping rib Upper abdomen or lower chest pain around the cos- also be helpful;​ a systematic 18-item syndrome 24,25,28 tal margin; ​caused by impingement of intercostal nerve between two costal cartilages (8th, 9th, or 10th) secondary patient questionnaire (Table 3) can to luxation of interchondral articulation;​ hooking maneuver be used to differentiate anterior cuta- or dynamic ultrasonography can be diagnostic neous nerve entrapment syndrome Sports hernia 20 Groin pain in athletes whose sport involves kicking and from irritable bowel syndrome, with twisting while running;​ caused by abdominal wall weakness a score of 10 or higher having 94% or injury;​ occurs without a palpable hernia sensitivity and 92% specificity for Thoracic spinal Radicular symptoms in dermatomal or myotomal distribu- anterior cutaneous nerve entrapment radiculopathy 30 tion;​ localized spine and paraspinal tenderness;​ myelopathy syndrome.6 symptoms in severe cases

Visceral pain localized Abdominal pain associated with constitutional or sys- EXAMINATION to the abdominal temic symptoms;​ possible gastrointestinal or genitourinary The Carnett test is a validated and cru- wall 28 symptoms cial tool in the evaluation of abdom- Xiphodynia 31 Reproducible lower chest or upper abdominal discomfort inal wall pain.2,28 The clinician places with light pressure on the xiphoid process;​ xiphoid process the patient in the supine position and deformity may be observed identifies the point of maximal ten- Information from references 7, 8, 16, 20, 22 through 26, and 28 through 31. derness on the abdomen;​ constant pressure is then applied to that spot.

432 American Family Physician www.aafp.org/afp Volume 98, Number 7 ◆ October 1, 2018 ABDOMINAL WALL PAIN

Next, the patient is asked to cross his or her arms over TABLE 3 the chest, then to lift the Abdominal Wall Pain Questionnaire head and shoulders from the examination table to tense Question Answer options 1 point if:​ Score the abdominal muscles. 1. How often do you experience bloating or a Mostly, regularly, Sometimes An alternative variant is to feeling of gas in the intestines? sometimes, or never or never have the patient raise both 2. Does pain exist on different spots all over the Yes or no No legs with knees extended. A abdomen? positive test elicits stable or 3. Does pain dominate over discomfort? Yes or no Yes worsened pain, indicating abdominal wall etiology. A 4. How often do you have pain when lying Mostly, regularly, Mostly or negative test, in which pain on the affected side? sometimes, or never regularly improves, suggests that the 5. How often does the stool have an Mostly, regularly, Sometimes pain is likely of intra-ab- abnormal consistency (e.g., hard and small, sometimes, or never or never dominal or visceral origin. pencil thin, loose, watery)? It can be challenging to 6. Does it feel like the pain originates Yes or no Yes interpret results in patients just beneath the skin? with psychogenic abdomi- 7. How often do you have sharp pain? Mostly, regularly, Mostly or nal pain. sometimes, or never regularly A modified Carnett test 8. Does it feel like the pain originates from Yes or no No for pelvic pain has been the gastrointestinal tract? described previously.32 In patients with tenderness 9. How often do you feel an urgent need for Mostly, regularly, Sometimes bowel movement without producing stool sometimes, or never or never during bimanual pelvic (incomplete defecation)? examination, the clinician 10. How often do you have pain when Mostly, regularly, Mostly or should locate the spot of coughing, sneezing, or squeezing? sometimes, or never regularly maximal tenderness and then remove his or her hand 11. Is the pain always located in the same spot? Yes or no Yes from the abdomen without 12. Is the pain just lateral to the midline Yes or no Yes changing the location and of the abdomen? pressure of the vaginal fin- 13. Is the pain related to an altered Yes or no No gers to see whether the pain defecation pattern? changes. The clinician can 14. How often do you have pain with daily activi- Mostly, regularly, Mostly or then replace the abdomi- ties (e.g., walking, sitting, cycling, bending)? sometimes, or never regularly nal hand on the tender spot and retract the vaginal fin- 15. How often does the painful spot feel strange, Mostly, regularly, Mostly or different, or dull? sometimes, or never regularly ger to see whether the pain changes. The test is positive 16. How often does stress provoke the pain? Mostly, regularly, Sometimes when external abdominal sometimes, or never or never palpation elicits pain. 17. Can you show with the tip of your finger Yes or no Yes In addition to the Carnett where the most intense pain is? test, other components of the 18. How often do you have pain when Mostly, regularly, Mostly or physical examination include pushing on the tender spot? sometimes, or never regularly a pelvic examination for women with lower abdomi- Total score: nal pain; ​a neurologic exam- Note: ​ A score ≥ 10 suggests diagnosis of anterior cutaneous nerve entrapment syndrome over irritable ination, including sensory bowel syndrome, with 94% sensitivity and 92% specificity. dermatome determination;​ Adapted with permission from van Assen T, de Jager-Kievit JW, Scheltinga MR, Roumen RM. Chronic muscle strength testing;​ a abdominal wall pain misdiagnosed as functional abdominal pain. J Am Board Fam Med. 2013;26(6):​ 741.​ thoracic spine examination;​

October 1, 2018 ◆ Volume 98, Number 7 www.aafp.org/afp American Family Physician 433 ABDOMINAL WALL PAIN

and detection of abdominal defects, masses, or bulging. FIGURE 3

The hooking maneuver, in Abdominal pain which the examiner hooks curved fingers under the inferior rib margins and Positive Carnett test? pulls anteriorly to reproduce pain in the lower chest and Yes No upper abdominal area, can Yes help diagnose slipping rib Clinical findings suggest intra-abdominal Evaluation for visceral disease? intra-abdominal syndrome.24 • Constitutional symptoms visceral disease • Gastrointestinal symptoms DIAGNOSTIC IMAGING • Genitourinary symptoms AND PROCEDURES • Pain changes with eating or defecation Ultrasonography, especially • Colicky pain point-of-care ultrasonogra- • Elevated white blood cell count,eryth- phy, can be useful in evalu- rocyte sedimentation rate, C-reactive protein level, or lactate level ating abdominal wall pain. It can be used to detect No masses, abscesses, hemato- Yes T7-T12 tenderness, Radicular or mas, tissue edema, and slip- ipsilateral spinal pain spinal source ping rib syndrome. It can No also offer dynamic evalua- Yes Yes tion for hernia and provide Mass or bulging Cyclic pain plus Abdominal wall guidance for therapeutic detected on examination history of uterine endometriosis or diagnostic trigger point or ultrasonography? surgery? injection. Other advanced No No imaging modalities, such Yes Yes Trigger point at Ilioinguinal Rectus sheath mass Rectus sheath as computed tomography groin incision? nerve plus decreasing hematoma and magnetic resonance entrapment hemoglobin level? No imaging, are generally not No Yes needed unless there is diag- Lateral rectus Anterior cuta- Yes nostic ambiguity or con- muscle pain? neous nerve Bulging with Hernia entrapment variable sizes? cern about intra-abdominal No etiology. No Yes Diagnostic trigger point Pain at pubic area? Sports hernia/ injection with or without myofascial Other painful No pain mass or lesion ultrasound guidance can Yes help confirm the diagnosis Pain at costal margin? Slipping rib of nerve entrapment.10,33-36 syndrome/ No costochondritis Ultrasound guidance is Yes preferred because it pro- Tenderness at Xyphodynia vides needle visualization to xyphoid process? avoid accidentally entering No the , and it helps the needle infiltrate Idiopathic the entire neurovascular Consider rare causes channel in patients with suspected anterior cuta- Algorithm for evaluation of abdominal wall pain. neous nerve entrapment Information from reference 11. syndrome. In trigger point

434 American Family Physician www.aafp.org/afp Volume 98, Number 7 ◆ October 1, 2018 ABDOMINAL WALL PAIN

injection, 5 to 10 mL of 1% to 2% lidocaine is injected deep entrapment, ultrasound, and trigger point injection. Search into the and muscle at the point of maximal ten- dates:​ February 2017 to June 2018. derness (see video at https://​www.aafp.org/journals/afp/ explore/video.html). Pain improvement of 50% or more The Authors confirms the diagnosis of abdominal wall pain. Pain res- BRIAN SHIAN, MD, is a clinical associate professor of family olution also occurs in about 20% to 30% of patients with medicine at the University of Iowa Carver College of Medi- anterior cutaneous nerve entrapment syndrome.5 cine, Iowa City. Electromyelography can be helpful in cases of suspected SCOTT T. LARSON, MD, is a clinical assistant professor of radiculopathy or neuropathy. An algorithm for the evalua- family medicine at the University of Iowa Carver College of tion of abdominal wall pain is presented in Figure 3.11 Medicine.

Treatment Address correspondence to Brian Shian, MD, University of Iowa Carver College of Medicine, 200 Hawkins Dr., 01291-E The management of abdominal wall pain depends on its PFP, Iowa City, IA 52242 (e-mail: ​brian-shian@​uiowa.edu). etiology. Patient education and reassurance may decrease Reprints are not available from the authors. patient anxiety, which subsequently reduces clinic visit fre- quency and patient insistence on undergoing unnecessary References expensive or invasive evaluations. 1. Cyriax EF. On various conditions that may stimulate the referred pain of Oral analgesics, muscle relaxants, and antispasmodics are visceral diseases and a consideration of these from the point of view of the most commonly prescribed medications for abdominal cause and effect.Practitioner . 1919;102:​ 314-322.​ wall pain. However, their effectiveness is inconsistent, and 2. Carnett JB. Intercostal neuralgia as a cause of abdominal pain and ten- their use is not evidence based.37 The same is true for local derness. Surg Gynecol Obstet. 1926;42:​ 625-632.​ 3. Ranger I, Mehta M, Pennington M. Abdominal wall pain due to nerve interventions such as icing, massage, and topical analgesics. entrapment. Practitioner. 1971;​206(236):​791-792. As discussed previously, ultrasound-guided trigger point 4. Applegate WV. Abdominal cutaneous nerve entrapment syndrome. injection can confirm the diagnosis of abdominal wall pain Surgery. 1972;​71(1):​118-124. caused by nerve entrapment while also providing symp- 5. Koop H, Koprdova S, Schürmann C. Chronic abdominal wall pain. Dtsch tom relief. Because of the relatively high failure rate of local Arztebl Int. 2016;​113(4):​51-57. 6. van Assen T, de Jager-Kievit JW, Scheltinga MR, Roumen RM. Chronic anesthetic injection, a combination of local anesthetic and abdominal wall pain misdiagnosed as functional abdominal pain. J Am other agents such as corticosteroids, onabotulinumtoxinA Board Fam Med. 2013;​26(6):​738-744. (Botox), and phenol are sometimes used. Corticosteroids 7. Lindsetmo RO, Stulberg J. Chronic abdominal wall pain—a diagnostic are the most commonly used and have a response rate of challenge for the surgeon. Am J Surg. 2009;​198(1):​129-134. 70% to 99%10,33-36 (eTable A). Alternatives to local injection 8. Suleiman S, Johnston DE. The abdominal wall: ​an overlooked source of pain. Am Fam Physician. 2001;64(3):​ 431-438.​ include transversus abdominis plane block, rectus sheath 9. Gallegos NC, Hobsley M. Abdominal wall pain:​ an alternative diagnosis. plane block, chemical neurolysis with phenol, or radiofre- Br J Surg. 1990;77(10):​ 1167-1170.​ quency denervation; ​however, the effectiveness and safety 10. Shute WB. Abdominal wall pain—the primary diagnosis. Zentralbl Gyna- of these modalities are not well documented.37 Surgical kol. 1984;106(5):​ 309-313.​ neurectomy, in which a portion of the entrapped nerve is 11. Srinivasan R, Greenbaum DS. Chronic abdominal wall pain:​ a frequently overlooked problem. Practical approach to diagnosis and manage- surgically removed, can be considered in cases of anterior ment. Am J Gastroenterol. 2002;97(4):​ 824-830.​ cutaneous nerve entrapment syndrome that require more 12. Costanza CD, Longstreth GF, Liu AL. Chronic abdominal wall pain:​ clin- than two injections. A stepwise management approach— ical features, health care costs, and long-term outcome. Clin Gastroen- beginning with local trigger point injection followed by terol Hepatol. 2004;2(5):​ 395-399.​ 37-39 13. McGarrity TJ, Peters DJ, Thompson C, McGarrity SJ. Outcome of neurectomy—is recommended (eFigure A). patients with chronic abdominal pain referred to chronic pain clinic. Surgical intervention may be necessary for hernia, endo- Am J Gastroenterol. 2000;95(7):​ 1812-1816.​ metriosis, slipping rib syndrome, abdominal wall mass or 14. Mui J, Allaire C, Williams C, Yong PJ. Abdominal wall pain in women abscess, rectal sheath hematoma, xiphodynia, or sports her- with chronic pelvic pain. J Obstet Gynaecol Can. 2016;​38(2):​154-159. 15. Anterior abdominal wall. In: ​Morton DA, Foreman KB, Albertine KH, eds. nia when conservative management is ineffective. The Big Picture: ​Gross Anatomy. New York, NY: ​McGraw Hill Medical;​ 2011:​85-96. This article updates a previous article on this topic by Suleiman and Johnston.8 16. Clarke S, Kanakarajan S. Abdominal cutaneous nerve entrapment syn- drome. Contin Educ Anaesth Crit Care Pain. 2015;15(2):​ 60-63.​ https://​ Data Sources: ​ We searched PubMed, the Cochrane database, academic.oup.com/bjaed/article/15/2/60/248606. Accessed May 3, Essential Evidence Plus, and Guidelines.gov using the following 2018. terms in various combinations: ​diagnosis, management, treat- 17. Mol FM, Lataster A, Scheltinga M, Roumen R. Anatomy of abdominal ment, therapy, abdominal wall pain, anterior cutaneous nerve anterior cutaneous intercostal nerves with respect to the pathophysiol-

October 1, 2018 ◆ Volume 98, Number 7 www.aafp.org/afp American Family Physician 435 ABDOMINAL WALL PAIN

ogy of anterior cutaneous nerve entrapment syndrome (ACNES):​ a case 29. Longstreth GF. Diabetic thoracic polyradiculopathy. Best Pract Res Clin study. Translational Res Anat. 2017;8-9:​ 6-10.​ Gastroenterol. 2005;19(2):​ 275-281.​ 18. Applegate WV, Buckwalter NR. Microanatomy of the structures con- 30. O’Connor RC, Andary MT, Russo RB, DeLano M. Thoracic radiculopa- tributing to abdominal cutaneous nerve entrapment syndrome. J Am thy. Phys Med Rehabil Clin N Am. 2002;13(3):​ 623-644,​ viii. Board Fam Pract. 1997;10(5):​ 329-332.​ 31. Howell JM. Xiphodynia:​ a report of three cases. J Emerg Med. 1992;​ 19. Sippo WC, Gomez AC. Nerve-entrapment syndromes from lower 10(4):435-438.​ abdominal surgery. J Fam Pract. 1987;25(6):​ 585-587.​ 32. Baker HW. The abdominal wall as a source of pain. J Ky Med Assoc. 20. Cavalli M, Bombini G, Campanelli G. Pubic inguinal pain syndrome: ​the 1973;​71(5):​309-310. so-called sports hernia. Surg Technol Int. 2014;24:​ 189-194.​ 33. Boelens OB, Scheltinga MR, Houterman S, Roumen RM. Randomized 21. Towfigh S, Anderson S, Walker A. When it is not a Spigelian hernia:​ clinical trial of trigger point infiltration with lidocaine to diagnose anterior abdominal cutaneous nerve entrapment syndrome. Am Surg. 2013;​ cutaneous nerve entrapment syndrome. Br J Surg. 2013;​100(2):​217-221. 79(10):​1111-1114. 34. Alnahhas MF, Oxentenko SC, Locke GR III, et al. Outcomes of ultra- 22. Khan Z, Zanfagnin V, El-Nashar SA, Famuyide AO, Daftary GS, Hopkins sound-guided trigger point injection for abdominal wall pain. Dig Dis MR. Risk factors, clinical presentation, and outcomes for abdominal Sci. 2016;​61(2):​572-577. wall endometriosis. J Minim Invasive Gynecol. 2017;​24(3):​478-484. 35. Kuan LC, Li YT, Chen FM, Tseng CJ, Wu SF, Kuo TC. Efficacy of treating abdominal wall pain by local injection. Taiwan J Obstet Gynecol. 2006;​ 23. Ding Y, Zhu J. A retrospective review of abdominal wall endometriosis 45(3):​239-243. in Shanghai, China. Int J Gynaecol Obstet. 2013;​121(1):​41-44. 36. Bourne IH. Treatment of painful conditions of the abdominal wall with 24. Heinz GJ, Zavala DC. Slipping rib syndrome. JAMA. 1977;237(8):​ ​ local injections. Practitioner. 1980;​224(1347):​921-925. 794-795. 37. Chrona E, Kostopanagiotou G, Damigos D, Batistaki C. Anterior cutane- 25. Meuwly JY, Wicky S, Schnyder P, Lepori D. Slipping rib syndrome: ​a place ous nerve entrapment syndrome:​ management challenges. J Pain Res. for sonography in the diagnosis of a frequently overlooked cause of 2017;10:​ 145-156.​ abdominal or low thoracic pain. J Ultrasound Med. 2002;​21(3):​339-343. 38. Oor JE, Ünlü Ç, Hazebroek EJ. A systematic review of the treatment for 26. Cherry WB, Mueller PS. Rectus sheath hematoma:​ review of 126 cases abdominal cutaneous nerve entrapment syndrome. Am J Surg. 2016;​ at a single institution. Medicine (Baltimore). 2006;​85(2):​105-110. 212(1):165-174.​ 27. Karaca B, Tarakci H, Tumer E, Calik S, Sen N, Sivrikoz ON. Primary 39. Boelens OB, van Assen T, Houterman S, Scheltinga MR, Roumen RM. abdominal wall actinomycosis. Hernia. 2015;​19(6):​1015-1018. A double-blind, randomized, controlled trial on surgery for chronic 28. Thomson H, Francis DM. Abdominal-wall tenderness: ​a useful sign in abdominal pain due to anterior cutaneous nerve entrapment syn- the acute abdomen. Lancet. 1977;2(8047):​ 1053-1054.​ drome. Ann Surg. 2013;​257(5):​845-849.

436 American Family Physician www.aafp.org/afp Volume 98, Number 7 ◆ October 1, 2018 ABDOMINAL WALL PAIN

eTABLE A

Regimens for Trigger Point Injections for Abdominal Wall Pain Corticosteroid Anesthetic Effectiveness

Betamethasone, 3 mg Bupivacaine (Marcaine) One injection: 70%A1 0.25% or lidocaine 1%, Overall (≥ 2 injections): NAA1 volume not specified

Betamethasone, 4 mg 2 mL bupivacaine 0.5% One injection: 68%A2 plus 3 mL lidocaine 2% Overall (≥ 2 injections): 95%A2

Methylprednisolone, Bupivacaine 0.25% or One injection: 70%A1 40 mg lidocaine 1%, volume not Overall (≥ 2 injections): NAA1 specified

1.5 to 2 mL lidocaine 2% One injection: 78%A3 Overall (≥ 2 injections): 99%A3

Triamcinolone, 10 mg 1 mL lidocaine 2% Overall: 89%A4

NA = not available. Information from: A1. Alnahhas MF, Oxentenko SC, Locke GR III, et al. Outcomes of ultrasound-guided trigger point injection for abdominal wall pain. Dig Dis Sci. 2016;61(2):572-577. A2. Bourne IH. Treatment of painful conditions of the abdominal wall with local injections. Practitioner. 1980;224(1347):921-925.​ A3. Shute WB. Abdominal wall pain—the primary diagnosis. Zentralbl Gynakol. 1984;106(5):​ ​ 309-313. A4. Kuan LC, Li YT, Chen FM, Tseng CJ, Wu SF, Kuo TC. Efficacy of treating abdominal wall pain by local injection. Taiwan J Obstet Gynecol. 2006;45(3):239-243.

October 1, 2018 ◆ Volume 98, Number 7 www.aafp.org/afp American Family Physician 436A ABDOMINAL WALL PAIN

eFIGURE A

History and Carnett test result suggest anterior cutaneous nerve entrapment syndrome

Local trigger point injection with anesthetic (preferably ultrasound = guided) confirms diagnosis if pain relief > 50%

Long-term pain relief?

No Yes

Repeat local trigger point Continue to monitor injection with anesthetic No further intervention plus corticosteroid

Long-term pain relief?

No Yes

Apply multimodal Continue to monitor approach No further intervention

Consider other ultrasound-guided Consider repeating local trigger Consider radiofrequency blocks on the affected side (trans- point injection with other agents ablation or neuro- versus abdominis plane block (e.g., phenol, alcohol, onabotuli- modulation techniques* or rectus sheath block) with or numtoxinA [Botox])* without corticosteroid

Long-term pain relief?

No Yes

Refer for anterior Continue to monitor surgical neurectomy* No further intervention

Long-term pain relief?

No Yes

Repeat neurectomy Continue to monitor (explorative neurectomy, No further intervention posterior neurectomy)*

*—Only in experienced centers.

Algorithm for management of anterior cutaneous nerve entrapment syndrome.

Adapted with permission from Chrona E, Kostopanagiotou G, Damigos D, Batistaki C. Anterior cutaneous nerve entrap- ment syndrome:​ management challenges. J Pain Res. 2017;​10:​155.

436B American Family Physician www.aafp.org/afp Volume 98, Number 7 ◆ October 1, 2018