ORIGINAL ARTICLE Efficacy of Transversus Abdominis Plane Steroid Injection for Treating Chronic Abdominal Pain Alaa Abd-Elsayed, MD, MPH*; David Malyuk, BS *Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin; Medical School, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, U.S.A & Abstract Background: Historically, transversus abdominis plane (TAP) block has been performed to treat acute abdominal pain that accompanies a variety of surgical procedures. This study represents an innovative approach in which the TAP block was performed on patients experiencing chronic abdominal pain who had failed other forms of pain management. Objective: To evaluate the efficacy of the TAP block procedure in patients experiencing chronic abdominal pain. Methods: In this retrospective chart review and data analysis, we reviewed the charts of 30 chronic abdominal pain patients previously treated with 45 TAP blocks after other forms of pain management had failed. We examined demographic data, surgical history, medication use, improvement following each block, and the side on which the procedure was performed. In unilateral blocks, 8 ml bupivacaine 0.25% mixed with 40 mg triamcinolone was injected. In bilateral blocks, 9 ml bupivacaine 0.25% and 40 mg triamcinolone were injected on each side. Analgesic efficacy was assessed via improvement in pain levels before and after the procedure was performed. Address correspondence and reprint requests to: Alaa Abd-Elsayed, MD, MPH, Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, B6/319 CSC, 600 Highland Avenue, Madison, WI 53792-3272, U.S.A. E-mail: alaaawny@hotmail.com. Disclosures This work was supported by the Shapiro Summer Research Program, University of Wisconsin School of Medicine and Public Health. Submitted: August 20, 2016; Revised February 14, 2017; Revision accepted: February 16, 2017 DOI. 10.1111/papr.12580 2017 World Institute of Pain, 1530-7085/18/$15.00 Pain Practice, Volume 18, Issue 1, 2018 48 52 Results: Transversus abdominis plane block improved pain in 79.5% of the performed blocks. The percentage improvement was 54.7% 36.4% for an average of 84 108 (0 to 490) days for the 44 procedures with complete data. There was significant reduction in the use of gabapentin before and after the procedure (P < 0.05). Conclusion: Transversus abdominis plane steroid injection can be a helpful in treating somatosensory chronic abdominal pain resistant to other therapeutic modalities. & Key Words: abdominal pain, transversus abdominis plane block INTRODUCTION Abdominal pain is a common patient complaint across the country, affecting millions of people each year. In 2006, 8 million emergency department visits in the United States were attributed to abdominal pain. 1 Chronic abdominal pain, which can persist for months after initial onset, can be particularly challenging to manage. Currently, options for directly treating chronic abdominal pain include anticonvulsants, antidepressants, anti-anxiety medications, sleep medications, topical medications such as lidocaine gel, multidisciplinary rehabilitation programs, complementary medicine, and opioids. Patients who are unable to take these medications or experience little relief from these modalities of pain management are left with few options to cope with chronic abdominal pain. New means of alleviating chronic abdominal pain could both improve patient quality of life and reduce the reliance on opioids for adequate pain control.
TAP Injection for Chronic Abdominal Pain 49 Transversus abdominis plane (TAP) block is a procedure in which local anesthetics, with or without steroids, are injected in between the internal oblique muscle and transversus abdominis muscle. The procedure is relatively new, first described by Rafi in 2001. 2 The TAP block provides analgesia to the parietal peritoneum as well as the skin and muscles of the anterior abdominal wall. Historically, this procedure has served as a component of a multimodal postoperative analgesia for a wide range of procedures to treat acute abdominal pain, commonly postsurgery. 3 However, little research has been performed in regard to its effectiveness in treating chronic abdominal pain. Recent studies have shown that a TAP block may be effective in patients who have exhausted alternative methods of chronic pain management. 4 An indwelling TAP block catheter was placed and successfully provided relief for a patient after several other interventions had failed, including epidural blocks, celiac plexus blocks, and transcutaneous electrical neural stimulation. It was the success of this reported case that indicated a need for further investigation. Our study involved a larger population of patients experiencing chronic pain and on whom a TAP block was subsequently performed. To our knowledge, this is the first study to discuss the efficacy of the TAP block in treating chronic abdominal pain. METHODS This was a retrospective analysis that included collecting data about all patients who received TAP blocks for treating chronic abdominal pain between January 1, 2014, and May 20, 2016. Patients were identified using current procedural terminology (CPT) codes from our billing system. This work received institutional review board exemption from the University of Wisconsin-Madison. All data were collected from our electronic medical records and entered into a Microsoft Excel spreadsheet. The study included 30 patients who received 45 TAP blocks (some patients received more than 1 block). Data collected included demographic data, surgical history, medication use, improvement following each block, and the side on which the procedure was performed. Main findings on history and physical examination which suggested that patients may have abdominal wall pain rather than visceral abdominal pain included patient description of feeling the pain to be superficial and not associated with serious gastrointestinal symptoms such as obstruction. Some patients described sensitivity to touch in the affected area, and some patients had several investigations for visceral disease, including upper and lower gastrointestinal endoscopies, the results of which were negative. Our main outcome was reported as percentage improvement in pain after performing the block. Technique Procedures were performed by 1 physician, using a similar approach and technique for each patient. After providing a written informed consent, each patient was placed in the supine position and the site was prepared in a sterile fashion. Ultrasound was used in all blocks to identify the TAP between the internal oblique and transversus abdominis muscle. The site was anesthetized using lidocaine 1%, and then a solution formed of bupivacaine 0.25% and triamcinolone was injected into the TAP after negative aspiration. In unilateral blocks, 8 ml of bupivacaine 0.25% mixed with 80 mg of triamcinolone was injected. In bilateral blocks, 9 ml of bupivacaine 0.25% and 40 mg of triamcinolone were injected on each side. Injections with a 22-gauge spinal needle on the syringe occurred under direct ultrasound visualization, insuring spread of the medication into the appropriate plane. The needle was flushed with lidocaine 1% and withdrawn. We refrained from using bupivacaine 0.5% to avoid the risk of motor weakness and abdominal distention that can happen with this concentration. We used bupivacaine 0.25%, which provided a reasonable duration of block and less risk for motor weakness. Statistical Analysis Analysis was carried out using IBM SPSS version 22 (IBM Corp., Armonk, NY, U.S.A.). Descriptive analysis was used to express data as n and % for categorical data and average standard deviation for numeric data. Before and after procedure variables were analyzed using the Wilcoxon signed-rank test. P value was considered significant at a level 0.05. RESULTS This study included 30 patients (21 females and 9 males, Table 1) who received 45 TAP blocks. Some blocks were performed at the subcostal level to treat high abdominal pain conditions. The blocks were performed
50 ABD-ELSAYED AND MALYUK Table 1. Patient Demographic Data (N = 30) Variable Total Race White 25 (83.3%) African American 3 (10%) Asian 1 (3.3%) Other 1 (3.3%) Gender Male 9 (30%) Female 21 (70%) Age (M SD) (range) 42.8 12.7 (20 to 72) BMI (M SD) (range) 31.4 7.8 (22 to 48) M, mean; SD, standard deviation; BMI, body mass index. Table 3. Gastrointestinal-Related Symptoms on Presentation Variable Constipation 5 Diarrhea 2 Nausea 7 Vomiting 3 Table 4. Duration of Improvement After Each Procedure (n = 44) n Duration in Days n (%) Table 2. Surgeries Performed Before Development of Pain Previous Abdominal Surgery* Abdominal laparoscopy 4 Appendectomy 9 Biliary tract surgery 1 Cesarean delivery 2 Laparoscopic cholecystectomy 8 Colectomy 1 Ovarian surgery 3 Pancreatic surgery 1 Kidney transplant 1 Bilateral tubal ligation 3 Laparotomy 2 Hemicolectomy 1 Hernia repair 7 Hysterectomy 3 Nephrectomy 5 Retroperitoneal mass removal 1 Right inguinal mass excision 1 Salpingectomy 1 Stomach surgery 1 Transverse colectomy 1 Photoselective vaporization of prostate 1 Xiphoid removal 1 Lysis of adhesions 4 *Five patients did not have abdominal surgeries before developing pain. after patients failed medication management. Twentyfive patients reported 1 or more abdominal surgeries before the development of pain, and they attributed their pain to surgery (Table 2). Eight blocks were performed on the left side, 12 on the right side, and 25 bilaterally. One patient missed the follow-up, 9 blocks were reported to be ineffective, and 6 patients reported ongoing improvement. The procedure improved pain in 79.5% of the performed blocks. At presentation, 17 patients reported some gastrointestinal symptoms in addition to the chronic abdominal pain, while the rest of the patients reported no gastrointestinal symptoms or complaints and pain was the sole complaint (Table 3). The percentage improvement was 54.7% 36.4% for a duration of 0 to 490 days and ongoing for the 44 n < 50 10 (22.7) 50 to 99 14 (31.8) 100 to 149 6 (13.6) 150 to 199 1 (2.3) 200 to 249 0 250 to 299 2 (4.5) 300 to 349 0 350 to 399 0 400 to 449 0 450 2 (4.5) One patient missed follow-up. Nine blocks were reported to be ineffective (20.5%). Six patients had ongoing pain relief at 60, 90 (3 patients), 139, and 490 days of follow-up (included in the table). Three patients reported less than 10 days of improvement; all other patients reported 29 days and more. blocks with complete data (excluding the 1 patient with the missing follow-up). There were no reported side effects in our study (Tables 4 and 5). We also reported medication consumption before and after the procedure, accounting for all medications used for treating pain, anxiety, and sleep. We found no significant change in medication use before and after the procedure for the following medications: acetaminophen, alprazolam, aspirin, baclofen, buspirone, celecoxib, clonazepam, cyclobenzaprine, diazepam, duloxetine, hyoscyamine, hydrocodone, hydromorphone, ibuprofen, lorazepam, ketoprofen, ketorolac, morphine, naproxen, nortriptyline, OxyContin, oxycodone, oxycodone hydrochloride and acetaminophen, pregabalin, sertraline, temazepam, tizanidine, tramadol, trazodone, zolpidem, diclofenac, fentanyl, lidocaine gel, lidocaine ointment, and lidocaine patch. However, there was significant reduction in the use of gabapentin before and after the procedure (P < 0.05). Our results on medications may not be accurate as some medications are taken as needed, and obtaining actual consumption from medical records was not possible. Our data are based on the prescriptions patients received before and after the blocks. Six patients had ongoing pain relief at follow-up (at 60 days; 3 patients at 90, 139, and 490 days).
TAP Injection for Chronic Abdominal Pain 51 Table 5. Percentage Improvement After Block as Compared to Baseline (n = 44) Percentage Improvement n (%) 1to9 0 10 to 19 0 20 to 29 3 (6.8) 30 to 39 1 (2.3) 40 to 49 2 (4.5) 50 to 59 8 (18.2) 60 to 69 2 (4.5) 70 to 79 2 (4.5) 80 to 89 5 (11.4) 90 to 99 4 (9.1) 100 8 (18.2) DISCUSSION Effective treatment of chronic abdominal pain is a challenging and often multifaceted problem. A variety of factors must be accounted for before selecting an ideal means of managing a given patient. Currently, the treatment options for directly treating abdominal pain are typically opioids and/or membrane-stabilizing agents. However, certain patients cannot be on opioids due to underlying social life factors, work life factors, and medical contraindications. Among a variety of other side effects, 25% of patients that utilize opioids for pain management experience nausea, 20% experience vomiting, and 23.9% experience mild sedation. Additional side effects include hyperalgesia, hypothalamic pituitary adrenal dysregulation, hypogonadism, tolerance, and addiction. 5 In certain instances, celiac plexus block, splanchnic nerve block, splanchnic radiofrequency ablation, and neuromodulation can be utilized to improve visceral pain if the origin of pain is from the viscera. In the event that these methods of pain management are deemed ineffective, patients and providers have limited options remaining. Innovative and reliable methods of alleviating chronic abdominal pain are necessary to improve patient quality of life and combat a reliance on opioids. It should be noted that the causes of chronic abdominal pain are quite broad. Up to 20% of patients seen in chronic pain clinics identify surgery as one of the causes of their pain. 6 Our study analyzed cases ranging from pain associated with surgery to pain associated with various forms of trauma, such as gunshot wounds. Patients underwent the TAP block procedure after other methods of pain management had failed. We noted that 5 patients developed pain without a previous history of abdominal surgery, and this might be attributed to entrapment neuropathy of unrecalled trauma. Despite a wide range of patient cases, 79.5% of our recorded patients experienced an improvement in pain level. Three of the remaining patients did not experience an improvement in pain level and have been implicated by providers for potential opioid-seeking behavior. Our study showed significant improvement in pain for variable periods of time (up to 490 days) after each block. All medication lists were retrieved from electronic patient databases. There was a significant reduction in the use of gabapentin before and after the procedure, suggesting potential effectiveness in pain management. The TAP block procedure has been shown to be diagnostically important when differentiating between visceral pain and somatosensory pain. 7 Due to the nature of this mode of analgesia, if a patient s pain was not derived from within the abdominal wall, the TAP block would not be an effective treatment option, potentially leading to varied outcomes with our patients. Patients with abdominal pain can utilize the TAP block not only as a therapeutic procedure but also as a diagnostic procedure. If it improves pain, this may suggest a somatosensory nature of pain with no need for further investigations (for detecting visceral causes of pain) that can be costly and associated with complications. Historically, the TAP block has been utilized in an acute setting to effectively treat pain immediately associated with surgery. Meta-analyses have indicated that the TAP block may serve as an effective treatment option for patients with contraindications to opioids and neuraxial anesthesia. 8 When compared to placebo, the TAP block improved pain scores and decreased opioid consumption at intervals within a 24-hour period. The TAP block was shown to be effective in postoperative pain management in gynecological procedures, bariatric surgery, appendectomy, and inguinal hernia repair. 8 Another recent study suggested that utilization of a TAP catheter technique for postoperative pain control after renal transplantation may be effective in treating postsurgical pain, showing less pentazocine requirement and less sedation in studied patients. 9 However, in light of the success of these reported cases, they represent a means of treating pain immediately associated with surgery and within other acute settings. One case report described a patient experiencing chronic abdominal pain during pregnancy who received pain relief after placement of a TAP catheter. 10 Unfortunately, little published research has investigated the analgesic potential of the TAP block months after onset of pain. Our study shows a very reasonable success of
52 ABD-ELSAYED AND MALYUK this procedure in treating chronic abdominal pain, which is a difficult kind of pain to treat and can fail all other therapeutic modalities. Limitations This was a retrospective analysis depending on the accuracy of reporting in our electronic medical records. No functional outcomes were measured. The main outcome, percentage improvement in pain after the procedure, had been accurately recorded in our medical records. Recommendations 1. TAP block with steroid injection and with ultrasound guidance can be an excellent modality for treating chronic pain resistant to other treatment modalities. 2. TAP blocks can be used as a diagnostic procedure to detect the source of a patient s abdominal pain. These blocks help avoid unnecessary gastrointestinal investigations that are commonly performed in patients with abdominal pain. This has to be considered on a case-by-case basis based on history, physical examination, and physicians evaluation of the condition. CONCLUSION Our study suggests that TAP steroid injections can improve pain scores in patients with somatosensory chronic abdominal pain resistant to other therapeutic modalities. Future randomized, controlled trials measuring more outcomes are necessary to confirm our finding. ACKNOWLEDGEMENTS Dr. Abd-Elsayed has activities outside this work that include research funding from Innocoll and Axsome and medical consultancy for Ultimaxx Health, Innocoll, Medtronic, and Axsome. CONFLICT OF INTEREST The authors have no conflict of interests related to this work. REFERENCES 1. Pitts SR, Niska RW, Xu J, Burt CW. National Hospital Ambulatory Medical Care Survey: 2006 emergency department summary. Natl Health Stat Rep. 2008;7:1 38. 2. Lissauer J, Mancuso K, Merritt C, Prabhakar A, Kaye AD, Urman RD. Evolution of the transversus abdominis plane block and its role in postoperative analgesia. Best Pract Res Clin Anaesthesiol. 2014;28:117 126. 3. Young MJ, Gorlin AW, Modest VE, Quraishi SA. Clinical implications of the transversus abdominis plane block in adults. Anesthesiol Res Pract. 2012;2012:731645. 4. Guirguis MN, Abd-Elsayed AA, Girgis G, Soliman LM. Ultrasound-guided transversus abdominis plane catheter for chronic abdominal pain. Pain Pract. 2013;13:235 238. 5. Wells N, Pasero C, McCaffery M. Improving the quality of care through pain assessment and management. In: Hughes RG, ed. Patient Safety and Quality: An Evidence- Based Handbook for Nurses. Rockville, MD: Agency for Healthcare Research and Quality; 2008:9: Chapter 17. 6. Macrae WA. Chronic pain after surgery. Br J Anaesth. 2001;87:88 98. 7. Soliman LM, Narouze S. Ultrasound-guided transversus abdominis plan block for the management of abdominal pain: an alternative to differential epidural block. Tech Reg Anesth Pain Manage. 2009;13:117 120. 8. Brogi E, Kazan R, Cyr S, Giunta F, Hemmerling TM. Transversus abdominal plane block for postoperative analgesia: a systematic review and meta-analysis of randomizedcontrolled trials. Can J Anaesth. 2016;63:1184 1196. 9. Parikh BK, Waghmare V, Shah VR, et al. The analgesic efficacy of continuous transversus abdominis plane block in renal transplant recipients. J Anaesthesiol Clin Pharmacol. 2015;31:531 534. 10. Miller EC, Szeto M, Boet S. Unilateral transversus abdominis plane block catheter for the treatment of abdominal wall pain in pregnancy: a case report. Reg Anesth Pain Med. 2015;40:720 722.