Anesth Pain Med 2015; 10: 16-20 http://dx.doi.org/10.17085/apm.2015.10.1.16 ￭Case Report￭

Myofascial pain syndrome of mimicking lumbar radiculitis -A case report-

Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea

Joong-Ho Park, Kwang-Suk Shim, Young-Min Shin, Chiu Lee, Sang-Gon Lee, and Eun-Ju Kim

Myofascial pain syndrome (MPS) can be characterized by pain difficult. Delays in making the correct diagnosis can result in caused by trigger points (TrPs) and fascial constrictions. Patients longer hospital stays, higher hospital fees, and unnecessary with MPS of the gluteus minimus muscles often complain of diagnostic tests and inadequate treatments. The authors have symptoms such as pain, especially when standing up after sitting or lying on the affected side, limping, and pain radiating down to successfully diagnosed and treated a patient with MPS of the the lower extremities. A 24-year-old female patient presenting with gluteus minimus initially diagnosed with lumbar radiculitis. motor and sensory impairments of both lower extremities was With thorough physical examination and injection of TrPs referred to our pain clinic after initially being diagnosed with lumbar radiculitis. Under the impression of MPS of the gluteus minimus under ultrasonography guidance, the patient was relieved of her muscles following through evaluation and physical examination of symptoms. We report this case to emphasize the importance of the patient, we performed trigger point injections under ultrasonography physical examination in patients presenting with symptoms guidance on the myofascial TrPs. Dramatic improvement of the suggestive of lumbar radiculitis. patient’s symptoms was observed following this treatment, and she was discharged without any further remaining symptoms. (Anesth Pain Med 2015; 10: 16-20) CASE REPORT Key Words: Myofascial pain syndromes, Radiculitis, Trigger A 24-year-old female patient (39 kg, 162 cm) was referred points, Ultrasonography. to the pain clinic complaining of tingling sensation and weakness of both legs. The patient was working as an Myofascial pain syndrome (MPS) of the gluteus minimus operating room nurse in a local medical center, and had no usually presents with symptoms such as hip pain and pain previous history of underlying diseases. She had a traumatic radiating down to the lower extremities [1]. However, since history of slipping and landing on her during duty six various other conditions, such as lumbar radiculitis, spinal weeks prior to her presentation. The patient's initial symptoms stenosis, trochanteric bursitis, trigger points (TrPs) of other hip included lower back pain with a tingling sensation in both abductor muscles, and articular dysfunction [2] may also buttocks and posterior . She was admitted to the local present with such symptoms, differential diagnosis may be medical center and underwent extensive diagnostic work-up including lumbar magnetic resonance imaging (MRI), pelvic Received: October 6, 2014. MRI, radiographic studies, and an -brachial index test Revised: October 10, 2014. Accepted: October 18, 2014. (ABI), of which all the results were unremarkable. During a month of admission, the patient was treated with three Corresponding author: Kwang-Suk Shim, M.D., Department of Anesthesiology interlaminar epidural steroid injections (IL ESI) and one and Pain Medicine, Daegu Fatima Hospital, 99, Ayang-ro, Dong-gu, Daegu 701-724, Korea. Tel: 82-53-940-7434, Fax: 82-53-940-7443, E-mail: transforaminal epidural steroid injection (TF ESI). She was [email protected] also treated with physical therapy and oral medications. Following the treatments, her lower back pain improved, but This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) the tingling sensations of the buttocks, posterior thighs, calves, which permits unrestricted non-commercial use, distribution, and reproduction in any and feet persisted in spite of unremarkable findings on medium, provided the original work is properly cited.

16 Joong-Ho Park, et al：Myofascial pain syndrome of gluteus 17 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

Fig. 1. Imaging of the gluteus region, transverse view. (A) The transducer is placed transversely over the gluteus minimus (red marking). (B) Transverse view of the gluteus region under ultrasonography guidance shows the gluteus minimus (arrow head) located deep beneath the (asterisk). The needle (arrows) is being inserted using the in-plane technique. diagnostic tests. The patient complained of these tingling and TrPs were located on both gluteus minimus muscles. sensations gradually aggravating, especially when she was When pressure was applied on the TrPs, symptoms identical to standing or walking. The symptoms were relieved when she those that were present when the patient was standing or was resting. Eventually, the symptoms were aggravated to the walking were observed. Other diagnostic physical examinations point at which the patient required a wheelchair for such as the straight leg raising test and FABER test were ambulation. For further evaluation and management, the patient unremarkable. was transferred to the department of neurosurgery in our Under the impression of MPS due to TrPs of the gluteus hospital. minimus muscles, we administered trigger point injections The patient was initially admitted to the neurosurgery under ultrasonography guidance using the in-plane approach on department, where she underwent an extensive work-up, the gluteus minimus muscles with 5 ml of 0.5% mepivacaine received physical therapy, and was given oral medications. on each side (Fig. 1). Mepivacaine was initially injected in the Lumbar radiography performed after admission showed no right gluteus minimus muscle. The insertion site was first definite fracture lines visible. Electromyography (EMG) results identified with palpation of the TrP, and was clarified by were unremarkable with no definite signs of neuropathy. More ultrasonography. A 23G 60 mm needle was inserted using the extensive imaging work-ups such as pelvic computed in-plane approach under ultrasonography guidance. When the tomography (CT) and lumbar MRI scans also showed no needle was inserted into the TrP, a local twitch response was definite lesions. The patient was referred to the pain clinic observed. Stretch therapy was applied following the injection. from the department of neurosurgery for further management. The patient’s symptoms were markedly reduced five minutes The patient initially arrived at the pain clinic in a wheelchair. after the injection. Her symptoms were reduced five minutes The patient complained of limping and a tingling sensation in after the injection, followed by stretch therapy, on the left side the buttocks during ambulation, especially when she was as well. After 20 minutes, the patient was able to walk back putting pressure on her . The symptoms were aggravated to the general ward without much difficulty. One day after the by walking, while they were relieved by resting or lying in initial injections, the patient reported mild tingling sensations, bed. Evaluations of the patient’s motor and sensory functions but did not experience much difficulty in walking. Two days revealed weakness during dorsiflexion (grade 4) and movement after the initial injections, the patient complained of the same of both great (grade 3), without significant sensory symptoms as the day before, and was given repeated trigger deficits. Palpation revealed severe tenderness on both buttocks, point injections with 5 ml of 0.5% mepivacaine under 18 Anesth Pain Med Vol. 10, No. 1, 2015 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏 ultrasonography guidance on each of her gluteus minimus gluteus minimus muscle originates from the glutea of the muscles followed by stretch therapy in the same manner as the ala ossis between the lineae gluteae anterior and initial injections. When she attempted ambulation 20 minutes posterior, while it inserts at the tip and lateral margin of the after the injections, her tingling sensations were resolved trochanter major [5]. dramatically. Upon her follow-up visit to the pain clinic two Myofascial TrPs of the gluteus minimus muscle can be days after the secondary injections, the patient reported almost activated by acute overload caused by falls, by walking too far no tingling sensations during ambulation, and the department or too fast, or by overuse. They can be perpetuated by of neurosurgery decided to discharge her. When she visited for prolonged immobility, such as prolonged standing or sitting. follow-up one week later, the patient was completely relieved Sacroiliac joint dysfunction can also activate and perpetuate of her symptoms, without any recurrence or adverse events. these gluteal TrPs [2]. Three months later, the patient visited the outpatient Patients with gluteus minimus TrPs usually complain of hip department for a follow-up, where she continued to report pain that may cause a limp during walking. Gluteus minimus doing well, with no the recurrence of her symptoms. The TrPs are accompanied by referred pain which can be persistent patient was subsequently lost to follow-up. and severe. The pain patterns vary depending on the location of the TrPs. TrPs in the anterior part of the gluteus minimus DISCUSSION muscle tend to affect the lower lateral buttock down to the lateral aspect of the lower extremity and can be similar to the Delays in diagnosis can result in undesired outcomes pain pattern of an L5 radiculitis. TrPs in the posterior part of including longer hospital stays, higher hospital fees, the gluteus minimus have a more posterior pattern that begins unnecessary diagnostic tests, and inappropriate treatments. In at the lower medial buttock down to the posterior and the case discussed here, the patient had visited other medical , which can be mistaken for an S1 radiculitis. Besides facilities, undergoing extensive diagnostic tests and therapeutic lumbar radiculitis, other conditions to be differentiated from interventions, with minimal improvements in symptoms, before TrPs of the gluteus minimus include trochanteric bursitis, TrPs being referred to our clinic. The authors were able to of other hip abductor muscles, and articular dysfunction [2]. successfully diagnose and treat the patient with physical Such radiating pain patterns may imitate sciatica [6], which examination and TrP injections with ultrasonography guidance, may delay diagnosis. Many patients presenting with lower back and have felt the need to emphasize the importance of pain or buttock pain accompanied by radiating leg pain are physical examination. often misdiagnosed with sciatica and are referred for lumbar Low back pain with radiating leg pain has a high spine management [6]. Accurate diagnosis is essential, since prevalence in the general population, varying from 9.9% to different management may be required depending on the cause 25% [3]. In a study by Chen and Nizar [4] involving 126 of the symptoms. The pain can be of either myofascial or patients with MPS in chronic back pain, demographics showed neurological origins. When physical examinations are absent of that the symptoms were more prevalent in female patients sensory and motor neurological findings, Sheon [7] suggested (68.7%) compared to male patients (31.3%), with the mean that “pseudosciatica” is a more appropriate term than age of patients ranging between 48.5 ± 15.0 years, and the “sciatica”. In these cases, bursitis and myofascial pain may be was found to be the most common muscle likely to be the cause of the symptoms, instead of lumbar affected in the lower part of the body. It was also documented radiculitis. Myofascial TrPs in the posterior gluteus minimus that the most common secondary causes of MPS were facet muscle can be a common source of sciatica [8], but this cause joint disorder (43.1%), spinal stenosis (33.8%), prolapsed of sciatica can be easily overlooked if the clinician does not intervertebral disc (30.8%), sacroiliac joint disorder (26.2%), carefully examine the muscles [2]. and failed back surgery syndrome (13.8%). Occupational TrPs of the muscles of the hip abductors should be factors showed that MPS were most prevalent in housewives distinguished from each other during diagnosis. They are (30%). usually distinguished by pain patterns and the location of the The gluteus minimus muscle is the deepest and the smallest TrPs. The gluteus minimus and piriformis are located adjacent of the three . It assists the gluteus medius to each other and generate similar patterns of referred pain. muscle in stabilizing the level during ambulation. The While pain from the gluteus minimus may sometimes radiate Joong-Ho Park, et al：Myofascial pain syndrome of gluteus 19 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏 down to the ankle, the piriformis pain extends only as far as of the hip revealed TrPs on the gluteus minimus muscles. The the and rarely causes back pain over the sacrum [9]. authors applied injections to the TrPs of the gluteus minimus Differentiation of TrPs in the gluteus minimus by palpation is muscles, resulting in dramatic relief of the patient’s symptoms. usually difficult since it is overlapped by the gluteus medius. Misdiagnosis of many different conditions involving lower Diagnosis in this situation is also usually made by the pain back pain or hip pain associated with radiating leg pain as patterns, in which TrPs from the gluteus medius are less likely lumbar radiculitis appears to be more common than expected. to involve the thigh, and low back pain in the sacral and Connell et al. [14] have reported that one of the most sacroiliac regions is more likely to be caused by the gluteus common overlooked causes of hip and leg pain is gluteus medius muscle. minimus and medius tendinosis. Kingzett-Taylor et al. [15] pain syndrome, also known as trochanteric have reported that many patients with such symptoms are bursitis, is a condition involving chronic, intermittent pain misdiagnosed as having lumbar spine disease and referred for accompanied by tenderness to palpation overlying the lateral MRI to aid in differential diagnosis. It is noteworthy that in aspect of the hip [10]. However, advances in imaging the case discussed here, the patient claimed that her visit to techniques and surgical findings have revealed that actual our pain clinic was the first time any physician tested for bursal involvement is uncommon [11]. Greater trochanter pain TrPs. Advances in diagnostic tools and blind faith in their syndrome often mimics pain generated from other sources, power may have led to negligence on the part of providers such as myofascial pain, degenerative joint disease and spinal regarding the importance of physical examination. Such negligence pathology. Plain radiographs are usually unremarkable, but can result in increased hospital fees, longer admissions, and calcifications around the greater trochanter may be observed. delayed diagnosis and treatment. Bewyer and Bewyer [6] have Ultrasound and MRI scans may show abductor suggested that recognition of the possibility of pseudo-sciatica thickening, tendinopathy and partial or full thickness tears [12]. may well reduce the number of imaging studies ordered and A distended bursa may be noted as a septated low attenuation accelerate accurate treatment and diagnosis. lesion at the site of insertion of the gluteus muscles on hip MPS of the gluteus minimus may often mimic the symptoms CT [13]. of lumbar radiculitis. Therefore, it can be argued that MRI, In our case, the patient was initially treated with epidural EMG, and ABIs were not completely unnecessary in this case. steroid injections under the impression of lumbar radiculitis. However, early and meticulous physical examination could The patient did undergo several diagnostic tests including have led to an earlier diagnosis and treatment, and decreased lumbar spine MRI, ABI, EMG, and hip CT, which all hospital fees. We report this case as a reminder of, and to contributed to diminishing the possibilities of other conditions emphasize the importance of, physical examination. such as lumbar radiculitis, vascular occlusion, sacroiliac joint dysfunction, and trochanteric bursitis. However, despite the REFERENCES negative results obtained from these diagnostic tests, there was a long delay until accurate diagnosis. It can be assumed that 1. Simons DG, Travell JG. Myofascial origins of low back pain. 3. the traumatic history of falling down on her buttocks, and the Pelvic and lower extremity muscles. Postgrad Med 1983; 73: initial symptoms consisting of lower back pain and sciatica, 99-105, 108. may have led to the impression of lumbar radiculitis. 2. Travell JG, Simons DB. Myofascial pain and dysfunction: the Consequentially, the patient was given IL ESIs and a TF ESI, trigger point Manual: Volume 2: The lower extremities. Baltimore, Williams & Wilkins. 1983, pp 150-85. resulting only in minimal and temporary relief. Partial relieving 3. Van Boxem K, Cheng J, Patijn J, van Kleef M, Lataster A, of the patient’s symptoms following the epidural steroid Mekhail N, et al. 11. Lumbosacral radicular pain. Pain Pract 2010; injections, however, may also have encouraged the possibility 10: 339-58. of misdiagnosis, resulting in two more subsequent IL ESIs and 4. Chen CK, Nizar AJ. Myofascial pain syndrome in chronic back a TF ESI. The anatomical location of the gluteus minimus pain patients. Korean J Pain 2011; 24: 100-4. muscle, which is located deep in the gluteal musculature, can 5. Irnich D. Myofascial Trigger Points: Comprehensive diagnosis and treatment. Edinburgh, Churchill Livingstone/Elsevier. 2013, pp make finding of the TrPs by palpation more difficult. This 469-79. also may have led to delays in diagnosis. When the patient 6. Bewyer DC, Bewyer KJ. Rationale for treatment of hip abductor was referred to our pain clinic, thorough physical examination pain syndrome. Iowa Orthop J 2003; 23: 57-60. 20 Anesth Pain Med Vol. 10, No. 1, 2015 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

7. Sheon RP. Soft tissue rheumatic pain. Compr Ther 1982; 8: 19-27. tendinopathy in greater trochanteric pain syndrome. Eur Radiol 8. Travell J. Symposium on the mechanisms and management of pain 2006; 17: 1772-83. syndromes. Proc Rudolf Virchow Med Soc 1957; 16: 128-36. 13. Varma DG, Parihar A, Richli WR. CT appearance of the distended 9.Choi JR, Lee JW, Lee KS, So KY. Studies on the piriformis trochanteric bursa. J Comput Assist Tomogr 1993; 17: 141-3. syndrome. J Korean Pain Soc 1996; 9: 120-5. 14. Connell DA, Bass C, Sykes CA, Young D, Edwards E. 10. Williams BS, Cohen SP. Greater trochanteric pain syndrome: a Sonographic evaluation of gluteus medius and minimus review of anatomy, diagnosis and treatment. Anesth Analg 2009; tendinopathy. Eur Radiol 2003; 13: 1339-47. 108: 1662-70. 15. Kingzett-Taylor A, Tirman PF, Feller J, McGann W, Prieto V, 11. Straus EJ, Nho SJ, Kelly BT. Greater trochanteric pain syndrome. Wischer T, et al. Tendinosis and tears of gluteus medius and Sports Med Arthrosc 2010; 18: 113-9. minimus muscles as a cause of hip pain: MR imaging findings. 12. Kong A, Van der Vliet A, Zadow S. MRI and US of gluteal AJR Am J Roentgenol 1999; 173: 1123-6.