- Email: [email protected]
Osteoid Osteoma of the Spinoglenoid Notch Mimicking Cervical Radiculopathy
Case Presentation
Osteoid Osteoma of the Spinoglenoid Notch Mimicking Cervical Radiculopathy Sabrina Paganoni, MD, PhD, Laurence DeBree Higgins, MD, Zacharia Isaac, MD INTRODUCTION Osteoid osteomas are benign skeletal neoplasms that are most commonly seen in persons who are in their 20s and 30s [1]. Characteristically, patients report having severe focal pain that worsens at night and with activity and that is relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). Osteoid osteomas can occur in any bone. However, they typically involve the cortex of long bones and, in more than 50% of cases, they are localized to the lower limbs. Rarely osteoid osteomas may occur in the scapula, where they have been reported in the glenoid, acromion, and coracoid process [2-5]. The diagnosis is based on clinical and radiologic evaluation. However, plain radiographs and even magnetic resonance imaging (MRI) are not always diagnostic, which may lead to a delay in diagnosis [6]. We report the case of a young, healthy man in whom progressive and debilitating right shoulder pain developed. The initial clinical impression pointed to subacromial impingement as the most likely pain generator, followed by cervical radiculopathy. Computed tomography (CT) showed the presence of a right spinoglenoid notch osteoid osteoma. The patient had excellent functional results after CT-guided radiofrequency ablation.
CASE PRESENTATION A 24-year-old right-handed man presented to his primary care physician in May 2008 with a chief complaint of right shoulder pain for 3 months. The pain began suddenly while playing basketball. He denied any trauma to the right shoulder or any prior episode of shoulder discomfort. The pain was exacerbated by shoulder forward flexion and abduction, and had progressively worsened to the point that it was difficult for him to put on a jacket or reach overhead. The pain woke him up at night. His medical history was significant only for dyslipidemia, for which he was taking nicotinic acid. Results of the initial physical examination revealed decreased active range of motion of the right shoulder (abduction to 60°, forward flexion to 90°, internal rotation to sacrum, and external rotation to 60°) and positive impingement maneuvers (positive Neer sign, Hawkins test, and Jobe test). His right shoulder and arm strength was preserved overall, although subtle weakness on the right was detected upon strength testing with a handheld dynamometer. Diagnostic studies of the right shoulder included a set of radiographs (internal rotation, external rotation, axillary, and scapular Y views), which did not reveal any abnormality. MRI was significant for a small partial-thickness tear at the insertion of the right supraspinatus tendon and a type II acromion. The patient was diagnosed with a right rotator cuff tear with subacromial impingement and was referred to physical therapy. He used over-the-counter NSAIDs as needed for pain with partial relief. During the next 10 months, the patient followed a physical therapy program that targeted range of motion, and he regained full range in his right shoulder. However, the intensity of the shoulder pain gradually increased, both at rest and with movements. The nighttime pain became more significant and started to interfere with his mood and daytime function. He reported that his shoulder pain was “ruining his life.” The patient initially managed the pain with escalating doses of over-the-counter NSAIDs every 3-4 hours (up to 3600 mg of ibuprofen daily). To limit his NSAID intake, his pain management was later changed to a combination of acetaminophen, opioids, gabapentin, and nortriptyline. He also received 2 sets of trigger point injections to the right trapezius, acupuncture treatments, PM&R
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S.P. Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA. Disclosure: nothing to disclose L.D.H. Department of Orthopedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA. Disclosure: nothing to disclose Z.I. Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, 850 Boylston St, Suite 130, Chestnut Hill, MA 02467. Address correspondence to Z.I.; e-mail: [email protected] Disclosure: nothing to disclose Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org Submitted for publication July 7, 2010; accepted September 17 2010.
© 2011 by the American Academy of Physical Medicine and Rehabilitation Vol. 3, 280-283, March 2011 DOI: 10.1016/j.pmrj.2010.09.007
PM&R
Vol. 3, Iss. 3, 2011
281
Figure 1. Pain diagram 1 year after pain onset. Note the distribution of the pain over a large area involving the right neck, shoulder, and arm.
and cortisone injections to the right shoulder, with minimal relief. Of note, the patient’s pain began to involve the right side of the neck and posterior upper arm and forearm, which mimicked a cervical radiculopathy and prompted evaluation for additional pain generators (Figure 1). A cervical MRI showed a small central disk protrusion at C4-C5 and C5-C6, and a right paracentral annular tear at C5-C6, with no evidence of neuroforaminal narrowing. An electromyographic (EMG) study was consistent with right C5 radiculopathy based on the finding of fibrillation potentials in the deltoid and chronic denervation changes in the biceps and rhomboid major. Of note, needle EMG examination of the right supraspinatus, infraspinatus, and cervical paraspinals was nor-
Figure 2. Right shoulder radiograph (Grashey view) obtained 14 months after onset of pain. The arrow points to a 0.9 ⫻ 0.9-cm lucency with sclerotic borders projecting over the coracoid/scapular spine.
Figure 3. Right shoulder CT scan obtained 14 months after pain onset (axial view). The arrow points to a sharply demarcated 1-cm radiolucent lesion that contained a 0.4-mm sclerotic area (“nidus”) with mild surrounding sclerosis located within the spine of the scapula at the spinoglenoid notch.
mal. Given the discordant clinical impressions caused by a positive EMG study for radiculitis and the absence of significant MRI compressive abnormality, a fluoroscopically guided diagnostic right C5 cervical selective nerve root anesthetization was performed. The procedure was performed with local anesthetic, and 1% lidocaine was used to anesthetize the superficial skin and to generate a skin wheal. No sedation was used. The right C5 spinal nerve was anesthetized with 0.8 mL of 2% preservative-free lidocaine. The patient immediately completed pre- and postprocedural pain diagrams with the Visual Analog Scale pain severity rating. Because no reduction in pain occurred after the procedure, it was believed that the C5 nerve root was not the pain generator, and alternative diagnoses were pursued. Given the significant persistent and unexplained pain, a new set of diagnostic studies was ordered. A right shoulder radiograph revealed a 0.9 ⫻ 0.9 – cm lucency with sclerotic borders projecting over the coracoid/scapular spine. This lesion was visible on the Grashey view only (Figure 2). A CT arthrogram of the right shoulder showed a 1-cm lucent lesion with surrounding sclerosis that contained a central nidus, which was suggestive of an osteoid osteoma. The lesion was located at the spinoglenoid notch, immediately adjacent to the suprascapular nerve and artery (Figure 3). This study showed no evidence of rotator cuff tear or labral pathology. Clinically, the range of motion of the right shoulder remained full. However, shoulder strength testing was significant for
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patient continued to work on right shoulder strengthening and endurance. At his 9-month follow-up appointment, he was cleared to gradually resume playing baseball and tennis.
DISCUSSION
Figure 4. A CT scan (axial view) obtained 20 months after the onset of symptoms. The image was obtained just prior to radiofrequency ablation of the spinoglenoid notch osteoid osteoma that now measured 1.5 ⫻ 1.5 ⫻ 1.0 cm (arrow).
mild weakness in external rotation and abduction in the right shoulder compared with the left shoulder. Functionally, the shoulder pain was severely limiting the patient’s lifestyle. After exhausting conservative measures, 20 months after initial presentation, further invasive procedures were considered. The patient was not considered a surgical candidate because of the high risk for potential damage to the nearby suprascapular nerve and artery. He was referred to Interventional Radiology for minimally invasive CT-guided radiofrequency ablation (Figure 4) [7,8]. The procedure was performed with the patient under general anesthesia and lasted 2 hours. With use of a posterior percutaneous approach, a radiofrequency applicator was advanced under CT guidance and positioned inside the lesion. Three cycles of ablation, each lasting 6 minutes, were performed, with a target tissue temperature range of 90°C-95°C. The patient underwent the procedure without complications. EMG recording of the infraspinatus muscle was performed throughout the ablation to monitor for irritation of the suprascapular nerve. No abnormal spike of activity was seen on the EMG tracing. Examination of an intraoperative core biopsy specimen confirmed the diagnosis of osteoid osteoma. The patient had nearly complete resolution of shoulder pain within 5 days after the ablation. However, he reported having fatigue, especially with repetitive use of the right arm, and was told to refrain from heavy physical activity and lifting. Four weeks after the procedure, gentle strengthening exercises of the right shoulder with physical therapy was initiated. At the 3-month follow-up evaluation, the patient was pain free and had stopped taking all pain medications. He had resumed his daily activities with no limitations. The range of motion of his right shoulder was intact, and dynamometry testing demonstrated marked improvement in external rotation and abduction strength. During the next few months, with the assistance of his physical therapist, the
The literature includes only rare reports of osteoid osteomas in the shoulder region. This benign neoplasm has been described in the proximal humerus, clavicle, glenoid, acromion, and coracoid process and is an unusual cause of shoulder pain [2-5,9,10]. This case is unusual for several reasons: the location of the osteoid osteoma, the clinical pain referral pattern that mimicked cervical radiculitis, and concomitant degenerative changes in the cervical spine and shoulder rotator cuff muscles, which further confounded diagnosis. To our knowledge, this is the first report of an osteoid osteoma localized to the spinoglenoid notch. The spinoglenoid notch is a clinically relevant anatomic structure. Located in the dorsal aspect of the scapula, it is situated just lateral to the root of the scapular spine, which divides the surface into a smaller supraspinous fossa and a larger infraspinous fossa. As the suprascapular nerve descends into the shoulder area, it first sends motor innervation to the supraspinatus muscle located in the supraspinous fossa. It courses around the spinoglenoid notch through a fibro-osseous tunnel formed by the scapular spine and the spinoglenoid ligament and then terminates into 3 to 4 branches that supply motor function to the infraspinatus muscle [11,12]. In addition, the suprascapular nerve sends sensory branches to the coracohumeral and coracoacromial ligaments, the subacromial bursa, and the acromioclavicular and glenohumeral joints [11,13]. Anatomic studies also have identified a cutaneous branch to the proximal lateral arm in a minority of patients [13]. Suprascapular nerve injury at the spinoglenoid notch is generally secondary to entrapment by the spinoglenoid ligament, compression from a ganglion cyst, traction, or direct trauma [14,15]. Clinically, patients will present with posterior shoulder pain and infraspinatus muscle atrophy and dysfunction. In our patient, however, the shoulder pain radiated to the lateral neck and posterior upper arm and forearm, which resembles the symptoms reported by patients with cervical radiculitis. Of note, ablation of the osteoid osteoma resulted in complete pain resolution. The reasons behind the lack of focal pain and the presence of such a broad distribution of referred symptoms in our patient remain unclear. However, it is not uncommon in clinical practice to encounter patients who report pain in areas that one would not predict on the basis of imaging studies. As an example, previous work that involved pain referral patterns of the cervical disk, spinal nerve root, and zygapophyseal joints have all demonstrated pain referral pat-
PM&R
terns beyond the locally expected anatomic structure. Such studies used provocative cervical diskography, cervical nerve root stimulation, and cervical zygapophyseal joint anesthetization or distention and have shown that a patient’s reported pain often can extend beyond the expected pattern, possibly because of somatic referral [1620]. The finding of a mass in the spinoglenoid notch raises important concerns regarding the risk-benefit ratio assessment of medical management versus definitive treatment. The proximity of the notch to the suprascapular neurovascular bundle implies, on the one hand, the possibility of potential damage to these structures by a growing lesion and, on the other hand, a high risk of complications after operative intervention. Furthermore, in the case of an osteoid osteoma, natural history studies indicate that this type of lesion tends toward spontaneous regression over a number of years and that a 4.5% risk of recurrence exists after surgical resection [1]. Therefore conservative treatment has a role in this population, and this approach was attempted with our patient. However, the persistence of relentless and unbearable pain over time was a critical factor in the decision-making process, and he was later referred for surgical intervention. Traditionally, osteoid osteomas have been treated with surgical resection. More recently, minimally invasive techniques with potentially less bone destruction and quicker rehabilitation time have been developed [1,7]. In particular, radiofrequency ablation has been found safe and effective as a treatment of osteoid osteomas in the upper extremity [8]. Our patient tolerated the procedure well, and his functional recovery has been excellent.
CONCLUSION Although it is exceedingly rare for osteoid osteomas to occur in the shoulder region, they should be included in the differential diagnosis of shoulder and/or arm pain, particularly in young patients. Clues to the correct diagnosis include severe focal pain that worsens at night and responds to NSAIDs. However, the clinical presentation may be atypical, and the correct diagnosis may be missed on initial imaging studies. CT remains the criterion standard for diagnosis. Optimal management depends on the patient’s symptoms and the location of the lesion, and it includes both medical management and definitive treatment.
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ACKNOWLEDGMENT We thank the patient for consenting to have his case reported in this scientific article.
REFERENCES 1. Lee EH, Shafi M, Hui JH. Osteoid osteoma: a current review. J Pediatr Orthop 2006;26:695-700. 2. Mosheiff R, Liebergall M, Ziv I, Amir G, Segal D. Osteoid osteoma of the scapula. A case report and review of the literature. Clin Orthop Relat Res 1991;262:129-131. 3. Gracia IA, Itarte JI, Majo JB, Salo GB, Proubasta IR. Osteoid osteoma of the coracoid process. J South Orthop Assoc 2001;10:49-52. 4. Degreef I, Verduyckt J, Debeer P, De Smet L. An unusual cause of shoulder pain: osteoid osteoma of the acromion—a case report. J Shoulder Elbow Surg 2005;14:643-644. 5. Wasserlauf B, Gossett J, Rosenthal DI, Levine WN. Osteoid osteoma of the glenoid: minimally invasive treatment. Am J Orthop 2003;32:405407. 6. Youssef BA, Haddad MC, Zahrani A, et al. Osteoid osteoma and osteoblastoma: MRI appearances and the significance of ring enhancement. Eur Radiol 1996;6:291-296. 7. Volkmer D, Sichlau M, Rapp TB. The use of radiofrequency ablation in the treatment of musculoskeletal tumors. J Am Acad Orthop Surg 2009;17:737-743. 8. Soong M, Jupiter J, Rosenthal D. Radiofrequency ablation of osteoid osteoma in the upper extremity. J Hand Surg Am 2006;31:279-283. 9. Lepore L, Lepore S, Maffulli N. Osteoid osteoma of the clavicle. Bull Hosp Jt Dis 1995;54:43-45. 10. Miller SL, Hazrati Y, Klein MJ, Springfield DS, Flatow EL. Intraarticular osteoid osteoma of the proximal humerus: a case report. J Shoulder Elbow Surg 2003;12:94-96. 11. Bigliani LU, Dalsey RM, McCann PD, April EW. An anatomical study of the suprascapular nerve. Arthroscopy 1990;6:301-305. 12. Cummins CA, Anderson K, Bowen M, Nuber G, Roth SI. Anatomy and histological characteristics of the spinoglenoid ligament. J Bone Joint Surg Am 1998;80:1622-1625. 13. Cummins CA, Messer TM, Nuber GW. Suprascapular nerve entrapment. J Bone Joint Surg Am 2000;82:415-424. 14. Cummins CA, Bowen M, Anderson K, Messer T. Suprascapular nerve entrapment at the spinoglenoid notch in a professional baseball pitcher. Am J Sports Med 1999;27:810-812. 15. Van Zandijcke M, Casselman J. Suprascapular nerve entrapment at the spinoglenoid notch due to a ganglion cyst. J Neurol Neurosurg Psychiatry 1999;66:245. 16. Slipman CW, Plastaras CT, Palmitier RA, Huston CW, Sterenfeld EB. Symptom provocation of fluoroscopically guided cervical nerve root stimulation. Are dynatomal maps identical to dermatomal maps? Spine 1998;23:2235-2242. 17. Slipman CW, Plastaras C, Patel R, et al. Provocative cervical discography symptom mapping. Spine J 2005;5:381-388. 18. Bogduk N, Marsland A. The cervical zygapophysial joints as a source of neck pain. Spine 1988;13:610-617. 19. Aprill C, Dwyer A, Bogduk N. Cervical zygapophyseal joint pain patterns II: a clinical evaluation. Spine 1990;6:458-461. 20. Dwyer A, Aprill C, Bogduk N. Cervical zygapophyseal joint pain patterns I: a study in normal volunteers. Spine 1990;15:453-457.
Osteoid Osteoma of the Spinoglenoid Notch Mimicking Cervical Radiculopathy Sabrina Paganoni, MD, PhD, Laurence DeBree Higgins, MD, Zacharia Isaac, MD INTRODUCTION Osteoid osteomas are benign skeletal neoplasms that are most commonly seen in persons who are in their 20s and 30s [1]. Characteristically, patients report having severe focal pain that worsens at night and with activity and that is relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). Osteoid osteomas can occur in any bone. However, they typically involve the cortex of long bones and, in more than 50% of cases, they are localized to the lower limbs. Rarely osteoid osteomas may occur in the scapula, where they have been reported in the glenoid, acromion, and coracoid process [2-5]. The diagnosis is based on clinical and radiologic evaluation. However, plain radiographs and even magnetic resonance imaging (MRI) are not always diagnostic, which may lead to a delay in diagnosis [6]. We report the case of a young, healthy man in whom progressive and debilitating right shoulder pain developed. The initial clinical impression pointed to subacromial impingement as the most likely pain generator, followed by cervical radiculopathy. Computed tomography (CT) showed the presence of a right spinoglenoid notch osteoid osteoma. The patient had excellent functional results after CT-guided radiofrequency ablation.
CASE PRESENTATION A 24-year-old right-handed man presented to his primary care physician in May 2008 with a chief complaint of right shoulder pain for 3 months. The pain began suddenly while playing basketball. He denied any trauma to the right shoulder or any prior episode of shoulder discomfort. The pain was exacerbated by shoulder forward flexion and abduction, and had progressively worsened to the point that it was difficult for him to put on a jacket or reach overhead. The pain woke him up at night. His medical history was significant only for dyslipidemia, for which he was taking nicotinic acid. Results of the initial physical examination revealed decreased active range of motion of the right shoulder (abduction to 60°, forward flexion to 90°, internal rotation to sacrum, and external rotation to 60°) and positive impingement maneuvers (positive Neer sign, Hawkins test, and Jobe test). His right shoulder and arm strength was preserved overall, although subtle weakness on the right was detected upon strength testing with a handheld dynamometer. Diagnostic studies of the right shoulder included a set of radiographs (internal rotation, external rotation, axillary, and scapular Y views), which did not reveal any abnormality. MRI was significant for a small partial-thickness tear at the insertion of the right supraspinatus tendon and a type II acromion. The patient was diagnosed with a right rotator cuff tear with subacromial impingement and was referred to physical therapy. He used over-the-counter NSAIDs as needed for pain with partial relief. During the next 10 months, the patient followed a physical therapy program that targeted range of motion, and he regained full range in his right shoulder. However, the intensity of the shoulder pain gradually increased, both at rest and with movements. The nighttime pain became more significant and started to interfere with his mood and daytime function. He reported that his shoulder pain was “ruining his life.” The patient initially managed the pain with escalating doses of over-the-counter NSAIDs every 3-4 hours (up to 3600 mg of ibuprofen daily). To limit his NSAID intake, his pain management was later changed to a combination of acetaminophen, opioids, gabapentin, and nortriptyline. He also received 2 sets of trigger point injections to the right trapezius, acupuncture treatments, PM&R
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1934-1482/11/$36.00 Printed in U.S.A.
S.P. Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA. Disclosure: nothing to disclose L.D.H. Department of Orthopedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA. Disclosure: nothing to disclose Z.I. Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, 850 Boylston St, Suite 130, Chestnut Hill, MA 02467. Address correspondence to Z.I.; e-mail: [email protected] Disclosure: nothing to disclose Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org Submitted for publication July 7, 2010; accepted September 17 2010.
© 2011 by the American Academy of Physical Medicine and Rehabilitation Vol. 3, 280-283, March 2011 DOI: 10.1016/j.pmrj.2010.09.007
PM&R
Vol. 3, Iss. 3, 2011
281
Figure 1. Pain diagram 1 year after pain onset. Note the distribution of the pain over a large area involving the right neck, shoulder, and arm.
and cortisone injections to the right shoulder, with minimal relief. Of note, the patient’s pain began to involve the right side of the neck and posterior upper arm and forearm, which mimicked a cervical radiculopathy and prompted evaluation for additional pain generators (Figure 1). A cervical MRI showed a small central disk protrusion at C4-C5 and C5-C6, and a right paracentral annular tear at C5-C6, with no evidence of neuroforaminal narrowing. An electromyographic (EMG) study was consistent with right C5 radiculopathy based on the finding of fibrillation potentials in the deltoid and chronic denervation changes in the biceps and rhomboid major. Of note, needle EMG examination of the right supraspinatus, infraspinatus, and cervical paraspinals was nor-
Figure 2. Right shoulder radiograph (Grashey view) obtained 14 months after onset of pain. The arrow points to a 0.9 ⫻ 0.9-cm lucency with sclerotic borders projecting over the coracoid/scapular spine.
Figure 3. Right shoulder CT scan obtained 14 months after pain onset (axial view). The arrow points to a sharply demarcated 1-cm radiolucent lesion that contained a 0.4-mm sclerotic area (“nidus”) with mild surrounding sclerosis located within the spine of the scapula at the spinoglenoid notch.
mal. Given the discordant clinical impressions caused by a positive EMG study for radiculitis and the absence of significant MRI compressive abnormality, a fluoroscopically guided diagnostic right C5 cervical selective nerve root anesthetization was performed. The procedure was performed with local anesthetic, and 1% lidocaine was used to anesthetize the superficial skin and to generate a skin wheal. No sedation was used. The right C5 spinal nerve was anesthetized with 0.8 mL of 2% preservative-free lidocaine. The patient immediately completed pre- and postprocedural pain diagrams with the Visual Analog Scale pain severity rating. Because no reduction in pain occurred after the procedure, it was believed that the C5 nerve root was not the pain generator, and alternative diagnoses were pursued. Given the significant persistent and unexplained pain, a new set of diagnostic studies was ordered. A right shoulder radiograph revealed a 0.9 ⫻ 0.9 – cm lucency with sclerotic borders projecting over the coracoid/scapular spine. This lesion was visible on the Grashey view only (Figure 2). A CT arthrogram of the right shoulder showed a 1-cm lucent lesion with surrounding sclerosis that contained a central nidus, which was suggestive of an osteoid osteoma. The lesion was located at the spinoglenoid notch, immediately adjacent to the suprascapular nerve and artery (Figure 3). This study showed no evidence of rotator cuff tear or labral pathology. Clinically, the range of motion of the right shoulder remained full. However, shoulder strength testing was significant for
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OSTEOID OSTEOMA OF THE SPINOGLENOID NOTCH
patient continued to work on right shoulder strengthening and endurance. At his 9-month follow-up appointment, he was cleared to gradually resume playing baseball and tennis.
DISCUSSION
Figure 4. A CT scan (axial view) obtained 20 months after the onset of symptoms. The image was obtained just prior to radiofrequency ablation of the spinoglenoid notch osteoid osteoma that now measured 1.5 ⫻ 1.5 ⫻ 1.0 cm (arrow).
mild weakness in external rotation and abduction in the right shoulder compared with the left shoulder. Functionally, the shoulder pain was severely limiting the patient’s lifestyle. After exhausting conservative measures, 20 months after initial presentation, further invasive procedures were considered. The patient was not considered a surgical candidate because of the high risk for potential damage to the nearby suprascapular nerve and artery. He was referred to Interventional Radiology for minimally invasive CT-guided radiofrequency ablation (Figure 4) [7,8]. The procedure was performed with the patient under general anesthesia and lasted 2 hours. With use of a posterior percutaneous approach, a radiofrequency applicator was advanced under CT guidance and positioned inside the lesion. Three cycles of ablation, each lasting 6 minutes, were performed, with a target tissue temperature range of 90°C-95°C. The patient underwent the procedure without complications. EMG recording of the infraspinatus muscle was performed throughout the ablation to monitor for irritation of the suprascapular nerve. No abnormal spike of activity was seen on the EMG tracing. Examination of an intraoperative core biopsy specimen confirmed the diagnosis of osteoid osteoma. The patient had nearly complete resolution of shoulder pain within 5 days after the ablation. However, he reported having fatigue, especially with repetitive use of the right arm, and was told to refrain from heavy physical activity and lifting. Four weeks after the procedure, gentle strengthening exercises of the right shoulder with physical therapy was initiated. At the 3-month follow-up evaluation, the patient was pain free and had stopped taking all pain medications. He had resumed his daily activities with no limitations. The range of motion of his right shoulder was intact, and dynamometry testing demonstrated marked improvement in external rotation and abduction strength. During the next few months, with the assistance of his physical therapist, the
The literature includes only rare reports of osteoid osteomas in the shoulder region. This benign neoplasm has been described in the proximal humerus, clavicle, glenoid, acromion, and coracoid process and is an unusual cause of shoulder pain [2-5,9,10]. This case is unusual for several reasons: the location of the osteoid osteoma, the clinical pain referral pattern that mimicked cervical radiculitis, and concomitant degenerative changes in the cervical spine and shoulder rotator cuff muscles, which further confounded diagnosis. To our knowledge, this is the first report of an osteoid osteoma localized to the spinoglenoid notch. The spinoglenoid notch is a clinically relevant anatomic structure. Located in the dorsal aspect of the scapula, it is situated just lateral to the root of the scapular spine, which divides the surface into a smaller supraspinous fossa and a larger infraspinous fossa. As the suprascapular nerve descends into the shoulder area, it first sends motor innervation to the supraspinatus muscle located in the supraspinous fossa. It courses around the spinoglenoid notch through a fibro-osseous tunnel formed by the scapular spine and the spinoglenoid ligament and then terminates into 3 to 4 branches that supply motor function to the infraspinatus muscle [11,12]. In addition, the suprascapular nerve sends sensory branches to the coracohumeral and coracoacromial ligaments, the subacromial bursa, and the acromioclavicular and glenohumeral joints [11,13]. Anatomic studies also have identified a cutaneous branch to the proximal lateral arm in a minority of patients [13]. Suprascapular nerve injury at the spinoglenoid notch is generally secondary to entrapment by the spinoglenoid ligament, compression from a ganglion cyst, traction, or direct trauma [14,15]. Clinically, patients will present with posterior shoulder pain and infraspinatus muscle atrophy and dysfunction. In our patient, however, the shoulder pain radiated to the lateral neck and posterior upper arm and forearm, which resembles the symptoms reported by patients with cervical radiculitis. Of note, ablation of the osteoid osteoma resulted in complete pain resolution. The reasons behind the lack of focal pain and the presence of such a broad distribution of referred symptoms in our patient remain unclear. However, it is not uncommon in clinical practice to encounter patients who report pain in areas that one would not predict on the basis of imaging studies. As an example, previous work that involved pain referral patterns of the cervical disk, spinal nerve root, and zygapophyseal joints have all demonstrated pain referral pat-
PM&R
terns beyond the locally expected anatomic structure. Such studies used provocative cervical diskography, cervical nerve root stimulation, and cervical zygapophyseal joint anesthetization or distention and have shown that a patient’s reported pain often can extend beyond the expected pattern, possibly because of somatic referral [1620]. The finding of a mass in the spinoglenoid notch raises important concerns regarding the risk-benefit ratio assessment of medical management versus definitive treatment. The proximity of the notch to the suprascapular neurovascular bundle implies, on the one hand, the possibility of potential damage to these structures by a growing lesion and, on the other hand, a high risk of complications after operative intervention. Furthermore, in the case of an osteoid osteoma, natural history studies indicate that this type of lesion tends toward spontaneous regression over a number of years and that a 4.5% risk of recurrence exists after surgical resection [1]. Therefore conservative treatment has a role in this population, and this approach was attempted with our patient. However, the persistence of relentless and unbearable pain over time was a critical factor in the decision-making process, and he was later referred for surgical intervention. Traditionally, osteoid osteomas have been treated with surgical resection. More recently, minimally invasive techniques with potentially less bone destruction and quicker rehabilitation time have been developed [1,7]. In particular, radiofrequency ablation has been found safe and effective as a treatment of osteoid osteomas in the upper extremity [8]. Our patient tolerated the procedure well, and his functional recovery has been excellent.
CONCLUSION Although it is exceedingly rare for osteoid osteomas to occur in the shoulder region, they should be included in the differential diagnosis of shoulder and/or arm pain, particularly in young patients. Clues to the correct diagnosis include severe focal pain that worsens at night and responds to NSAIDs. However, the clinical presentation may be atypical, and the correct diagnosis may be missed on initial imaging studies. CT remains the criterion standard for diagnosis. Optimal management depends on the patient’s symptoms and the location of the lesion, and it includes both medical management and definitive treatment.
Vol. 3, Iss. 3, 2011
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ACKNOWLEDGMENT We thank the patient for consenting to have his case reported in this scientific article.
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