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Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases
Journal of Orthopaedic Science xxx (2015) 1e5
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Case report
Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases Hirokazu Saiwai a, *, Seiji Okada c, Kosei Miyazaki a, Ryuji Nakano b, Yukihide Iwamoto c, Kuniyoshi Tsuchiya a a b c
Department of Orthopedic Surgery, Japan Community Health Care Organization, Kyushu Hospital, Japan Department of Pathology, Japan Community Health Care Organization, Kyushu Hospital, Japan Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kyushu University, Japan
a r t i c l e i n f o Article history: Received 11 May 2015 Received in revised form 16 September 2015 Accepted 27 September 2015 Available online xxx
1. Introduction Intraspinal cysts can cause myelopathy or radiculopathy by compressing the spinal cord or nerve root. These cysts occur commonly in the lumbar or cervical spine and rarely at the thoracic level, because spinal instability is considered to be the cause of intraspinal cysts. Intraspinal cysts include synovial cysts, ganglion cysts, ligamentum flavum cysts, neurenteric cysts, arachnoid cyst. Among them, the most common types are synovial and ganglion cysts, which arise from facet joints. Synovial cysts are pathologically distinguished from ganglion cysts by having a thick wall lined by synovial cells. Diagnosis of ganglion cysts also can be made on the basis of the characteristic jelly-like fluid content. The ligamentum flavum also can form cysts when hemorrhage occurs inside, and these are called ligamentum flavum cysts. In this report, we present 3 cases of rare thoracic intraspinal cysts that were successfully treated by surgical resection; discuss the features of these cysts on preoperative images, the intraoperative findings, treatment options, and pathological findings; and review the relevant literature. 2. Report of the cases In 2014, three patients who had suffered spastic gait for several weeks up to 2 years, caused by myelopathy, were referred to our
* Corresponding author. Department of Orthopedic Surgery, Japan Community Health Care Organization, Kyushu Hospital, 1-8-1 Kishinoura, Yahata-Nishi ku, Kitakyushu city, Fukuoka, 806-8501, Japan. Tel.: þ81 93 641 5111; fax: þ81 93 642 1868. E-mail address: [email protected] (H. Saiwai).
hospital from other clinics. The average age of the patients was 78 years (range, 71e86 years), and all 3 patients were males. Preoperative magnetic resonance imaging (MRI) of the thoracolumbar spine was performed for all patients, and they were diagnosed with intraspinal cysts and surgically treated by the same spine surgeon. Two patients underwent microscopic surgery, and 1 patient underwent microendoscopic surgery. All the intraoperative findings were recorded on video, and the final diagnoses were confirmed by pathological examination. There are no symptoms to indicate cyst recurrence in all cases at 12 months follow-up. The patients and their families were informed that data from the case would be submitted for publication, and gave their consent. 2.1. Neurological preoperative findings In Case 1, the patient was a 71-year-old man who presented with right leg paresthesia that began about 2 years earlier. The area of paresthesia had expanded to both legs below both sides of the inguinal area, and his ability to ambulate was adversely affected. When he was referred to our hospital from the clinic where he had been treated, he needed crutches to walk outside because of spasticity. Physical examination revealed normal strength in his leg muscles but decreased sensation over the entire right calf. In Case 2, the patient was a 77-year-old man who was admitted to our hospital because of difficulties with ambulation since 3 months. Neurological examination demonstrated sensory impairment below the umbilical level on both sides. Motor function was normal, but he could not maintain a standing position because of severe myelopathy. He also had mild vesicorectal dysfunction (frequent micturition and constipation). In Case 3, the patient was an 86-year-old man who presented with rapid deterioration of ambulation within 1 week and came to the emergency room in our hospital. He could not stand up by himself because he would lose his sense of balance. The patients in Cases 1 and 2 were treated conservatively before they were referred to our hospital, but they did not show any improvement in symptoms. The clinical features of the patients are summarized in Table 1.
http://dx.doi.org/10.1016/j.jos.2015.09.004 0949-2658/© 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
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H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
Table 1 Clinical characteristics of the patients. Case
Age
Sex
Symptoms
Symptom duration
Level
Pathology
Treatment
1 2 3
71 77 86
Male Male Male
LE numbness difficulty w/gait LE numbness difficulty w/gait Difficulty w/gait
2 years 3 months 1 week
Th11/12 Th11/12 Th10/11
Ganglion cyst Ligamentum flavum cyst Ligamentum flavum cyst
Laminectomy/resection Laminectomy/resection Laminectomy/resection
Fig. 1. Preoperative magnetic resonance imaging (MRI) findings. Case 1 MRI demonstrating an extradural cystic lesion (arrow) with a hypointense signal on axial (a) T1-weighted imaging and a hyperintense signal on axial (b) and sagittal (c) T2-weighted imaging. Case 2 MRI demonstrating an extradural round cystic lesion (arrow) with isointense signal on axial (d) T1-weighted imaging and a thin dark rim and heterogeneous internal signal intensity on axial (e) and sagittal (f) T2-weighted imaging. Case 3 MRI demonstrating an extradural spindle-shaped cystic lesion (arrow) with isointensity on axial (g) T1-weighted imaging and heterogeneous signal intensity on axial (h) and sagittal (i) T2-weighted imaging.
2.2. Preoperative MRI findings Preoperative MRI was performed for all patients. In Case 1, MRI showed an extradural sharply marginated cystic lesion in the spinal canal at the T11/12 level, with a hypointense signal on T1-weighted imaging and a hyperintense signal on T2-weighted imaging (Fig. 1, AeC, AeC). This MRI finding indicated that the cyst contained water inside. In Case 2, a round cystic lesion was present with spinal cord compression at the Th11/12 level (Fig. 1, DeF). The cyst was isointense, indistinguishable from the ligament on T1-weighted
imaging, and had a thin dark rim and heterogeneous internal signal intensity on T2-weighted imaging. Spinal cord hyperintense signals were seen at the Th11/12 level on T2-weighted imaging. In Case 3, MRI showed a spindle-shaped lesion that was of relatively high intensity on T1-weighted imaging and showed heterogeneous signal intensity on T2-weighted imaging inside the anatomical region of the ligamentum flavum at the Th10/11 level (Fig. 1, GeI). In Cases 2 and 3, the MRI findings were not consistent with those of typical cystic lesions, such as ganglion cysts or synovial cysts, which show T1-hypointense and T2-hyperintense inside the cysts.
Fig. 2. Surgical findings. (a) A gray-white-colored cyst appeared beneath the right facet joint (asterisk). This cyst is not adhered to the dura mater. (b) The cyst was punctured, and a yellow jelly-like fluid exuded from the cyst. (c) A scar tissue-like mass is seen inside the ligamentum flavum (asterisk). This mass shows strong adhesion to the dura mater (arrow). (d) A cystic lesion is observed on the left side of the spinal canal that is compressing the dura mater (asterisk). The cyst is adhered to the ligamentum flavum to some extent.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
2.3. Intraoperative findings All of the patients were treated by surgical resection. In 2 patients (Cases 1 and 3), microscopic cyst resection was performed. The patient in Case 2 underwent mini-endoscopic cyst resection. In Case 1, after a routine Th11 laminotomy was performed, we observed a thickened ligamentum flavum, but no cystic lesion was initially found. After removing the entire ligamentum flavum, a gray-white-colored cyst appeared beneath the right facet joint (Fig. 2, A, A). This cyst was not adhered to the dura mater. Before the cyst was resected, it was punctured on site, and a yellow jelly-like fluid exuding from the cyst was observed (Fig. 2, B). In Case 2, we could not detect the cystic lesion even after the ligamentum flavum was released from the bilateral medial facets at Th11/12 level, but the flavum was strongly adhered to the dura mater. Because the flavum could not be removed entirely, we resected the superficial part of the flavum piece by piece. Then, a thickened scar tissue-like mass was observed inside the flavum (Fig. 2, C). The endoscopic procedure provided excellent visualization of the surgical area, which allowed viewing of the condition of the adhesion level between the scar tissue-like mass and dura mater. Therefore, we safely removed the mass together with the ligamentum flavum from the dura mater with careful handling by using a pituitary rongeur and Penfield dissector. The lesion was located at the
3
midline of the intraspinal space, and there seemed to be no connection between the lesion and both facet joints. In Case 3, after partial resection of the ligamentum flavum at the Th10/11 level, we observed a cystic lesion on the left side of the spinal canal that compressed the dura mater (Fig. 2, D). The cyst was adhered to the ligamentum flavum in some places. We removed the cyst as a whole mass with the surrounding ligamentum flavum. The macroscopic findings demonstrated that this 8-mm-long spindleshaped reddish cyst was filled with dark red gelatinous fluid which was considered hematoma. 2.4. Histopathological findings Histopathological examinations were performed in all cases. In Case 1, the cyst did not show synovial lining cells, but fibrous connective tissue that contained hyalinized scar tissue on its wall was present. However, degeneration of the ligamentum flavum surrounding the cyst was not severe, as shown by Elastica van Gieson staining (Fig. 3, A, A). The final diagnosis of a ganglion cyst was made on the basis of surgical and pathological examination findings. Cases 2 and 3 had similar histological findings on the sections and showed cartilaginous metaplasia and loss of elastic fibers in the ligamentum flavum, which suggested severe degeneration of the ligamentum flavum, in addition to
Fig. 3. Pathological findings. (a) Elastica van Gieson (EVG) staining showing that degeneration of the ligamentum flavum surrounding the cyst was mild. (b and d): EVG staining showing severe degeneration of the ligamentum flavum, which is fragmented. (c and e) Hematoxylin-eosin staining showing cartilaginous metaplasia of the ligamentum flavum. Scale bar, 100 mm.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
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H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
neovascularization, necrosis, and calcification with chronic inflammatory cell infiltration (Fig. 3, BeE). No synovial lining cells were observed in this section. Diagnosis of ligamentum flavum cyst was made on the basis of pathological findings. 3. Discussion Development of intraspinal cystic lesions is considered to be associated with excessive repetitive motion, due to instability, followed by degeneration of the facet joints or ligamentum flavum. The cervical and lumbar spinal segments have higher mobility than does the thoracic segment, which has the rib cage to provide stability; hence, it is reasonable to consider that the thoracic spine is the least common site for intraspinal cysts. In fact, intraspinal extradural thoracic cysts are very rare, and only a small number of cases have been reported: 13 reports of synovial cysts [1e13], 1 report of ganglion cysts [11], and 5 reports of ligamentum flavum cysts [14e18]. In most of the reported cases, cysts were generated in the levels of Th8 to Th12. The average age of all reported patients was 61.7 years (20 males and 10 females). Our case series consisted of 3 thoracic cysts: 1 ganglion cyst and 2 ligamentum flavum cysts. Interestingly, the periods during which the patients suffered from myelopathy varied until surgical treatment was needed. In the ganglion cyst case (Case 1), it took more than 2 years to develop gait inability after the patient started to have paresis in his legs. Hsu et al. reported a cyst with the features of both ganglion cysts and synovial cysts [19], which suggested that ganglion cysts could develop from synovial cysts that disconnected from the facet joint. These facts suggest that ganglion cysts may grow very slowly in size and originally might be synovial cysts that are not large enough to compress the spinal cord but eventually change into ganglion cysts. On the other hand, ligamentum flavum cysts develop in a completely different manner than do synovial cysts and ganglion cysts. Ligamentum flavum cysts are pseudo-cysts, as are ganglion cysts, and the pathogenesis of this cyst is associated with microtrauma of the ligamentum flavum that causes hemorrhage or myxoid degeneration due to instability combined with degenerative change of the ligamentum flavum [20,21]. In one of our ligamentum flavum cyst cases (Case 3), the patient came to the emergency room in our hospital because his myelopathy had rapidly worsened, and he could not walk or stand without support, which suggested that acute change in the size of the cyst might have occurred due to, for example, a hemorrhage inside the cyst, which then compressed the spinal cord. In our case series, all cases revealed herniated discs at the same levels as cyst formation in MRI. This suggests that large range of motion at lower thoracic spine causes intervertebral disc degeneration and segmental instability, which contributes to the formation of ganglion cysts or ligamentum flavum cysts. Normally, intraspinal cysts are detected by MRI for diagnosis of the cause of myelopathy or radiculopathy. Typical cysts, such as synovial cysts and ganglion cysts, always show hypointense T1weighted and hyperintense T2-weighted lesions inside the cysts (Fig. 1, AeC). Even though Cases 2 and 3 were both ligamentum flavum cysts at the final diagnoses, they showed completely different findings on MRI (Fig. 1, DeI). The cyst in Case 2 showed an extradural round cystic lesion with isointense signal on T1weighted imaging and a heterogeneous internal signal intensity on T2-weighted imaging. On the other hand, in Case 3, MRI showed an extradural spindle-shaped cystic lesion with relatively high intensity on T1-weighted imaging and heterogeneous signal intensity on T2-weighted imaging. Ligamentum flavum cysts contain cartilaginous metaplasia, calcification, necrotic tissue, and hematomas. The contents of this variety of cyst cause each ligamentum flavum cyst to show different signal intensities on MRI. In addition, the MRI
signal intensities of hematomas vary depending on the age of the blood. Hemoglobin in hematomas changes its form from oxyhemoglobin (isointense on T1, high intensity on T2) in the hyperacute phase to deoxyhemoglobin (low intensity on both T1 and T2) in the acute phase, to methemoglobin (high intensity on both T1 and T2) in the subacute phase, and to hemosiderin (low intensity on both T1 and T2) in the chronic phase [22]. In Case 2, MRI showed low intensity lesions on both T1 and T2 inside the cyst, which was consistent with a chronic-phase hematoma that contained hemosiderin because the patient's symptoms had continued for several months. In Case 3, MRI was performed about 7 days after the initial onset of the symptom. This timing was consistent with a hematoma that contained methemoglobin, which showed high intensity on both T1 and T2. The treatment options for intraspinal cysts include conservative approaches (bed rest, analgesics, and physical therapy), minimally invasive approaches (epidural/intra-articular corticosteroid injections, CT-guided aspiration of the cyst), and surgical resection. All 3 of our patients were treated by surgical resection because their myelopathy had worsened and their symptoms were too severe to treat conservatively. Some reports have shown that CT-guided minimally invasive treatment achieved sufficient symptomatic improvement [23,24]. This method is an important treatment option especially for high risk patients such as super-elderly. However, Martha et al. reported that more than half of 101 patients who had facet joint steroid injections with cyst rupture as lumbar synovial cyst treatment required subsequent cyst resection surgery to relieve their symptoms [25]. On the other hand, most of the case reports that have described surgical treatment have demonstrated good outcomes after cyst removal [11,13]. In our ligamentum flavum cyst cases (Cases 2 and 3), the cysts showed firm adhesion to the ligamentum flavum and dura mater. Therefore, it might be better to perform wide laminectomy to resect the entire cyst because if complete resection of the cyst is not performed, there is a risk of cyst recurrence. Onofrio and Mih also recommended wide decompression for cyst resection to reduce the risk of dural tears [26]. Microscopic or miniendoscopic surgery provides an excellent view of the surgical site, which minimizes the risk for dural tear caused by adhesion between cysts and surrounding tissues. Cyst recurrence has a greater chance of being prevented if microscopic or mini-endoscopic surgery that gives a closer view is performed to achieve complete cyst resection. Bydon et al. reported that after surgical resection of intraspinal cysts, same-level synovial cyst recurrence occurred up to 1.8% after decompression alone but no cyst recurrence observed after decompression and fusion [27]. Considering the fact that cysts' development have an association with spinal instability, cases with significant spondylosis or segmental instability need spinal fusion procedure in addition to laminactomy and cyst resection. In conclusion, it is not difficult to distinguish between ganglion cysts and ligamentum flavum cysts from preoperative MRI findings. Especially for ligamentum flavum cysts, most parts of the cysts are solid, and CT-guided cyst aspiration will not reduce the mass of the cyst that compresses the spinal cord. In addition, if the cyst has strong adhesion to the surrounding tissues, it makes the resection surgery more difficult. Therefore, accurate preoperative MRI differentiation of ligamentum flavum cysts from other kinds of cysts is important for selection of a treatment option (conservative, minimally invasive CT-guided aspiration, or surgery) and an appropriate surgical plan.
Conflict of interest The authors declare that they have no conflict of interest.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
References [1] Holtzman RN, Dubin R, Yang WC, Rorat E, Liu HM, Leeds NE. Bilateral symptomatic intraspinal T12-L1 synovial cysts. Surg Neurol 1987;28:225e30. [2] Awward EE, Martin DS, Bucholz RD, Sundaram M. Synovial cyst of the midthoracic spine. AJNR Am J Neuroradiol 1991;12:562e3. [3] Lopes NM, Aesse FF, Lopes DK. Compression of thoracic nerve root by a facet joint synovial cyst: case report. Surg Neurol 1992;38:338e40. [4] Doherty PF, Sherman BA, Stein C, White R. Bilateral synovial cysts of the thoracic spine: a case report. Surg Neurol 1993;39:279e81. [5] Freidberg SR, Fellows T, Thomas CB, Mancall AC. Experience with symptomatic spinal epidural cysts. Neurosurgery 1994;34:989e93. discussion 993. [6] Fritz RC, Kaiser JA, White AH, DeLong WB, Gamburd RS. Magnetic resonance imaging of a thoracic intraspinal synovial cyst. Spine (Phila Pa 1976) 1994;19: 487e90. [7] Hodges SD, Fronczak S, Zindrick MR, Lorenz MA, Vrbos LA. Extradural synovial thoracic cyst. Spine (Phila Pa 1976) 1994;19:2471e3. [8] Howington JU, Connolly ES, Voorhies RM. Intraspinal synovial cysts: 10-year experience at the ochsner clinic. J Neurosurg 1999;91:193e9. [9] Lynn B, Watkins RG, Watkins RI, Williams LA. Acute traumatic myelopathy secondary to a thoracic cyst in a professional football player. Spine (Phila Pa 1976) 2000;25:1593e5. [10] Graham E, Lenke LG, Hannallah D, Lauryssen C. Myelopathy induced by a thoracic intraspinal synovial cyst: case report and review of the literature. Spine (Phila Pa 1976) 2001;26:E392e4. [11] Cohen-Gadol AA, White JB, Lynch JJ, Miller GM, Krauss WE. Synovial cysts of the thoracic spine. J Neurosurg Spine 2004;1:52e7. [12] Almefty R, Arnautovic KI, Webber BL. Multilevel bilateral calcified thoracic spinal synovial cysts. J Neurosurg Spine 2008;8:473e7. [13] Merkle M, Psaras T, Tatagiba M, Danz S, Schmidt F. Synovial cyst of the thoracic spine causing myelopathy. Spine (Phila Pa 1976) 2009;34:E199e201. [14] Maezawa Y, Baba H, Uchida K, Kokubo Y, Kubota C, Noriki S. Ligamentum flavum hematoma in the thoracic spine. Clin Imaging 2001;25:265e7. [15] Miyakoshi N, Shimada Y, Okada K, Hongo M, Kasukawa Y, Itoi E. Ligamentum flavum hematoma in the rigid thoracic spinal segments: case report. J Neurosurg Spine 2005;2:495e7.
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[16] Sudo H, Abumi K, Ito M, Kotani Y, Takahata M, Hojo Y, Sanda M, Minami A. Spinal cord compression by ligamentum flavum hematoma in the thoracic spine. Spine (Phila Pa 1976) 2009;34:E942e4. [17] Matsumoto Y, Fujiwara T, Imamura R, Okada Y, Harimaya K, Doi T, Kawaguchi K, Okada S, Yamada Y, Oda Y, Iwamoto Y. Hematoma of the ligamentum flavum in the thoracic spine: report of two cases and possible role of the transforming growth factor beta-vascular endothelial growth factor signaling axis in its pathogenesis. J Orthop Sci 2013;18:347e54. [18] Wild F, Tuettenberg J, Grau A, Weis J, Krauss JK. Ligamentum flavum hematomas of the cervical and thoracic spine. Clin Neurol Neurosurg 2014;116: 24e7. [19] Hsu KY, Zucherman JF, Shea WJ, Jeffrey RA. Lumbar intraspinal synovial and ganglion cysts (facet cysts). Ten-year experience in evaluation and treatment. Spine (Phila Pa 1976) 1995;20:80e9. [20] Kao CC, Uihlein A, Bickel WH, Soule EH. Lumbar intraspinal extradural ganglion cyst. J Neurosurg 1968;29:168e72. [21] Sabo RA, Tracy PT, Weinger JM. A series of 60 juxtafacet cysts: clinical presentation, the role of spinal instability, and treatment. J Neurosurg 1996;85: 560e5. [22] Braun P, Kazmi K, Nogues-Melendez P, Mas-Estelles F, Aparici-Robles F. MRI findings in spinal subdural and epidural hematomas. Eur J Radiol 2007;64: 119e25. [23] Chang A. Percutaneous CT-guided treatment of lumbar facet joint synovial cysts. HSS J 2009;5:165e8. [24] Ramchandani A, Mitra R. Long-term resolution of symptoms from percutaneous lumbar synovial cyst aspiration: a visual vignette. Am J Phys Med Rehabil 2010;89:695e6. [25] Martha JF, Swaim B, Wang DA, Kim DH, Hill J, Bode R, Schwartz CE. Outcome of percutaneous rupture of lumbar synovial cysts: a case series of 101 patients. Spine J 2009;9:899e904. [26] Onofrio BM, Mih AD. Synovial cysts of the spine. Neurosurgery 1988;22: 642e7. [27] Bydon A, Xu R, Parker SL, McGirt MJ, Bydon M, Gokaslan ZL, Witham TF. Recurrent back and leg pain and cyst reformation after surgical resection of spinal synovial cysts: systematic review of reported postoperative outcomes. Spine J 2010;10:820e6.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Case report
Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases Hirokazu Saiwai a, *, Seiji Okada c, Kosei Miyazaki a, Ryuji Nakano b, Yukihide Iwamoto c, Kuniyoshi Tsuchiya a a b c
Department of Orthopedic Surgery, Japan Community Health Care Organization, Kyushu Hospital, Japan Department of Pathology, Japan Community Health Care Organization, Kyushu Hospital, Japan Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kyushu University, Japan
a r t i c l e i n f o Article history: Received 11 May 2015 Received in revised form 16 September 2015 Accepted 27 September 2015 Available online xxx
1. Introduction Intraspinal cysts can cause myelopathy or radiculopathy by compressing the spinal cord or nerve root. These cysts occur commonly in the lumbar or cervical spine and rarely at the thoracic level, because spinal instability is considered to be the cause of intraspinal cysts. Intraspinal cysts include synovial cysts, ganglion cysts, ligamentum flavum cysts, neurenteric cysts, arachnoid cyst. Among them, the most common types are synovial and ganglion cysts, which arise from facet joints. Synovial cysts are pathologically distinguished from ganglion cysts by having a thick wall lined by synovial cells. Diagnosis of ganglion cysts also can be made on the basis of the characteristic jelly-like fluid content. The ligamentum flavum also can form cysts when hemorrhage occurs inside, and these are called ligamentum flavum cysts. In this report, we present 3 cases of rare thoracic intraspinal cysts that were successfully treated by surgical resection; discuss the features of these cysts on preoperative images, the intraoperative findings, treatment options, and pathological findings; and review the relevant literature. 2. Report of the cases In 2014, three patients who had suffered spastic gait for several weeks up to 2 years, caused by myelopathy, were referred to our
* Corresponding author. Department of Orthopedic Surgery, Japan Community Health Care Organization, Kyushu Hospital, 1-8-1 Kishinoura, Yahata-Nishi ku, Kitakyushu city, Fukuoka, 806-8501, Japan. Tel.: þ81 93 641 5111; fax: þ81 93 642 1868. E-mail address: [email protected] (H. Saiwai).
hospital from other clinics. The average age of the patients was 78 years (range, 71e86 years), and all 3 patients were males. Preoperative magnetic resonance imaging (MRI) of the thoracolumbar spine was performed for all patients, and they were diagnosed with intraspinal cysts and surgically treated by the same spine surgeon. Two patients underwent microscopic surgery, and 1 patient underwent microendoscopic surgery. All the intraoperative findings were recorded on video, and the final diagnoses were confirmed by pathological examination. There are no symptoms to indicate cyst recurrence in all cases at 12 months follow-up. The patients and their families were informed that data from the case would be submitted for publication, and gave their consent. 2.1. Neurological preoperative findings In Case 1, the patient was a 71-year-old man who presented with right leg paresthesia that began about 2 years earlier. The area of paresthesia had expanded to both legs below both sides of the inguinal area, and his ability to ambulate was adversely affected. When he was referred to our hospital from the clinic where he had been treated, he needed crutches to walk outside because of spasticity. Physical examination revealed normal strength in his leg muscles but decreased sensation over the entire right calf. In Case 2, the patient was a 77-year-old man who was admitted to our hospital because of difficulties with ambulation since 3 months. Neurological examination demonstrated sensory impairment below the umbilical level on both sides. Motor function was normal, but he could not maintain a standing position because of severe myelopathy. He also had mild vesicorectal dysfunction (frequent micturition and constipation). In Case 3, the patient was an 86-year-old man who presented with rapid deterioration of ambulation within 1 week and came to the emergency room in our hospital. He could not stand up by himself because he would lose his sense of balance. The patients in Cases 1 and 2 were treated conservatively before they were referred to our hospital, but they did not show any improvement in symptoms. The clinical features of the patients are summarized in Table 1.
http://dx.doi.org/10.1016/j.jos.2015.09.004 0949-2658/© 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
2
H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
Table 1 Clinical characteristics of the patients. Case
Age
Sex
Symptoms
Symptom duration
Level
Pathology
Treatment
1 2 3
71 77 86
Male Male Male
LE numbness difficulty w/gait LE numbness difficulty w/gait Difficulty w/gait
2 years 3 months 1 week
Th11/12 Th11/12 Th10/11
Ganglion cyst Ligamentum flavum cyst Ligamentum flavum cyst
Laminectomy/resection Laminectomy/resection Laminectomy/resection
Fig. 1. Preoperative magnetic resonance imaging (MRI) findings. Case 1 MRI demonstrating an extradural cystic lesion (arrow) with a hypointense signal on axial (a) T1-weighted imaging and a hyperintense signal on axial (b) and sagittal (c) T2-weighted imaging. Case 2 MRI demonstrating an extradural round cystic lesion (arrow) with isointense signal on axial (d) T1-weighted imaging and a thin dark rim and heterogeneous internal signal intensity on axial (e) and sagittal (f) T2-weighted imaging. Case 3 MRI demonstrating an extradural spindle-shaped cystic lesion (arrow) with isointensity on axial (g) T1-weighted imaging and heterogeneous signal intensity on axial (h) and sagittal (i) T2-weighted imaging.
2.2. Preoperative MRI findings Preoperative MRI was performed for all patients. In Case 1, MRI showed an extradural sharply marginated cystic lesion in the spinal canal at the T11/12 level, with a hypointense signal on T1-weighted imaging and a hyperintense signal on T2-weighted imaging (Fig. 1, AeC, AeC). This MRI finding indicated that the cyst contained water inside. In Case 2, a round cystic lesion was present with spinal cord compression at the Th11/12 level (Fig. 1, DeF). The cyst was isointense, indistinguishable from the ligament on T1-weighted
imaging, and had a thin dark rim and heterogeneous internal signal intensity on T2-weighted imaging. Spinal cord hyperintense signals were seen at the Th11/12 level on T2-weighted imaging. In Case 3, MRI showed a spindle-shaped lesion that was of relatively high intensity on T1-weighted imaging and showed heterogeneous signal intensity on T2-weighted imaging inside the anatomical region of the ligamentum flavum at the Th10/11 level (Fig. 1, GeI). In Cases 2 and 3, the MRI findings were not consistent with those of typical cystic lesions, such as ganglion cysts or synovial cysts, which show T1-hypointense and T2-hyperintense inside the cysts.
Fig. 2. Surgical findings. (a) A gray-white-colored cyst appeared beneath the right facet joint (asterisk). This cyst is not adhered to the dura mater. (b) The cyst was punctured, and a yellow jelly-like fluid exuded from the cyst. (c) A scar tissue-like mass is seen inside the ligamentum flavum (asterisk). This mass shows strong adhesion to the dura mater (arrow). (d) A cystic lesion is observed on the left side of the spinal canal that is compressing the dura mater (asterisk). The cyst is adhered to the ligamentum flavum to some extent.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
2.3. Intraoperative findings All of the patients were treated by surgical resection. In 2 patients (Cases 1 and 3), microscopic cyst resection was performed. The patient in Case 2 underwent mini-endoscopic cyst resection. In Case 1, after a routine Th11 laminotomy was performed, we observed a thickened ligamentum flavum, but no cystic lesion was initially found. After removing the entire ligamentum flavum, a gray-white-colored cyst appeared beneath the right facet joint (Fig. 2, A, A). This cyst was not adhered to the dura mater. Before the cyst was resected, it was punctured on site, and a yellow jelly-like fluid exuding from the cyst was observed (Fig. 2, B). In Case 2, we could not detect the cystic lesion even after the ligamentum flavum was released from the bilateral medial facets at Th11/12 level, but the flavum was strongly adhered to the dura mater. Because the flavum could not be removed entirely, we resected the superficial part of the flavum piece by piece. Then, a thickened scar tissue-like mass was observed inside the flavum (Fig. 2, C). The endoscopic procedure provided excellent visualization of the surgical area, which allowed viewing of the condition of the adhesion level between the scar tissue-like mass and dura mater. Therefore, we safely removed the mass together with the ligamentum flavum from the dura mater with careful handling by using a pituitary rongeur and Penfield dissector. The lesion was located at the
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midline of the intraspinal space, and there seemed to be no connection between the lesion and both facet joints. In Case 3, after partial resection of the ligamentum flavum at the Th10/11 level, we observed a cystic lesion on the left side of the spinal canal that compressed the dura mater (Fig. 2, D). The cyst was adhered to the ligamentum flavum in some places. We removed the cyst as a whole mass with the surrounding ligamentum flavum. The macroscopic findings demonstrated that this 8-mm-long spindleshaped reddish cyst was filled with dark red gelatinous fluid which was considered hematoma. 2.4. Histopathological findings Histopathological examinations were performed in all cases. In Case 1, the cyst did not show synovial lining cells, but fibrous connective tissue that contained hyalinized scar tissue on its wall was present. However, degeneration of the ligamentum flavum surrounding the cyst was not severe, as shown by Elastica van Gieson staining (Fig. 3, A, A). The final diagnosis of a ganglion cyst was made on the basis of surgical and pathological examination findings. Cases 2 and 3 had similar histological findings on the sections and showed cartilaginous metaplasia and loss of elastic fibers in the ligamentum flavum, which suggested severe degeneration of the ligamentum flavum, in addition to
Fig. 3. Pathological findings. (a) Elastica van Gieson (EVG) staining showing that degeneration of the ligamentum flavum surrounding the cyst was mild. (b and d): EVG staining showing severe degeneration of the ligamentum flavum, which is fragmented. (c and e) Hematoxylin-eosin staining showing cartilaginous metaplasia of the ligamentum flavum. Scale bar, 100 mm.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
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H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
neovascularization, necrosis, and calcification with chronic inflammatory cell infiltration (Fig. 3, BeE). No synovial lining cells were observed in this section. Diagnosis of ligamentum flavum cyst was made on the basis of pathological findings. 3. Discussion Development of intraspinal cystic lesions is considered to be associated with excessive repetitive motion, due to instability, followed by degeneration of the facet joints or ligamentum flavum. The cervical and lumbar spinal segments have higher mobility than does the thoracic segment, which has the rib cage to provide stability; hence, it is reasonable to consider that the thoracic spine is the least common site for intraspinal cysts. In fact, intraspinal extradural thoracic cysts are very rare, and only a small number of cases have been reported: 13 reports of synovial cysts [1e13], 1 report of ganglion cysts [11], and 5 reports of ligamentum flavum cysts [14e18]. In most of the reported cases, cysts were generated in the levels of Th8 to Th12. The average age of all reported patients was 61.7 years (20 males and 10 females). Our case series consisted of 3 thoracic cysts: 1 ganglion cyst and 2 ligamentum flavum cysts. Interestingly, the periods during which the patients suffered from myelopathy varied until surgical treatment was needed. In the ganglion cyst case (Case 1), it took more than 2 years to develop gait inability after the patient started to have paresis in his legs. Hsu et al. reported a cyst with the features of both ganglion cysts and synovial cysts [19], which suggested that ganglion cysts could develop from synovial cysts that disconnected from the facet joint. These facts suggest that ganglion cysts may grow very slowly in size and originally might be synovial cysts that are not large enough to compress the spinal cord but eventually change into ganglion cysts. On the other hand, ligamentum flavum cysts develop in a completely different manner than do synovial cysts and ganglion cysts. Ligamentum flavum cysts are pseudo-cysts, as are ganglion cysts, and the pathogenesis of this cyst is associated with microtrauma of the ligamentum flavum that causes hemorrhage or myxoid degeneration due to instability combined with degenerative change of the ligamentum flavum [20,21]. In one of our ligamentum flavum cyst cases (Case 3), the patient came to the emergency room in our hospital because his myelopathy had rapidly worsened, and he could not walk or stand without support, which suggested that acute change in the size of the cyst might have occurred due to, for example, a hemorrhage inside the cyst, which then compressed the spinal cord. In our case series, all cases revealed herniated discs at the same levels as cyst formation in MRI. This suggests that large range of motion at lower thoracic spine causes intervertebral disc degeneration and segmental instability, which contributes to the formation of ganglion cysts or ligamentum flavum cysts. Normally, intraspinal cysts are detected by MRI for diagnosis of the cause of myelopathy or radiculopathy. Typical cysts, such as synovial cysts and ganglion cysts, always show hypointense T1weighted and hyperintense T2-weighted lesions inside the cysts (Fig. 1, AeC). Even though Cases 2 and 3 were both ligamentum flavum cysts at the final diagnoses, they showed completely different findings on MRI (Fig. 1, DeI). The cyst in Case 2 showed an extradural round cystic lesion with isointense signal on T1weighted imaging and a heterogeneous internal signal intensity on T2-weighted imaging. On the other hand, in Case 3, MRI showed an extradural spindle-shaped cystic lesion with relatively high intensity on T1-weighted imaging and heterogeneous signal intensity on T2-weighted imaging. Ligamentum flavum cysts contain cartilaginous metaplasia, calcification, necrotic tissue, and hematomas. The contents of this variety of cyst cause each ligamentum flavum cyst to show different signal intensities on MRI. In addition, the MRI
signal intensities of hematomas vary depending on the age of the blood. Hemoglobin in hematomas changes its form from oxyhemoglobin (isointense on T1, high intensity on T2) in the hyperacute phase to deoxyhemoglobin (low intensity on both T1 and T2) in the acute phase, to methemoglobin (high intensity on both T1 and T2) in the subacute phase, and to hemosiderin (low intensity on both T1 and T2) in the chronic phase [22]. In Case 2, MRI showed low intensity lesions on both T1 and T2 inside the cyst, which was consistent with a chronic-phase hematoma that contained hemosiderin because the patient's symptoms had continued for several months. In Case 3, MRI was performed about 7 days after the initial onset of the symptom. This timing was consistent with a hematoma that contained methemoglobin, which showed high intensity on both T1 and T2. The treatment options for intraspinal cysts include conservative approaches (bed rest, analgesics, and physical therapy), minimally invasive approaches (epidural/intra-articular corticosteroid injections, CT-guided aspiration of the cyst), and surgical resection. All 3 of our patients were treated by surgical resection because their myelopathy had worsened and their symptoms were too severe to treat conservatively. Some reports have shown that CT-guided minimally invasive treatment achieved sufficient symptomatic improvement [23,24]. This method is an important treatment option especially for high risk patients such as super-elderly. However, Martha et al. reported that more than half of 101 patients who had facet joint steroid injections with cyst rupture as lumbar synovial cyst treatment required subsequent cyst resection surgery to relieve their symptoms [25]. On the other hand, most of the case reports that have described surgical treatment have demonstrated good outcomes after cyst removal [11,13]. In our ligamentum flavum cyst cases (Cases 2 and 3), the cysts showed firm adhesion to the ligamentum flavum and dura mater. Therefore, it might be better to perform wide laminectomy to resect the entire cyst because if complete resection of the cyst is not performed, there is a risk of cyst recurrence. Onofrio and Mih also recommended wide decompression for cyst resection to reduce the risk of dural tears [26]. Microscopic or miniendoscopic surgery provides an excellent view of the surgical site, which minimizes the risk for dural tear caused by adhesion between cysts and surrounding tissues. Cyst recurrence has a greater chance of being prevented if microscopic or mini-endoscopic surgery that gives a closer view is performed to achieve complete cyst resection. Bydon et al. reported that after surgical resection of intraspinal cysts, same-level synovial cyst recurrence occurred up to 1.8% after decompression alone but no cyst recurrence observed after decompression and fusion [27]. Considering the fact that cysts' development have an association with spinal instability, cases with significant spondylosis or segmental instability need spinal fusion procedure in addition to laminactomy and cyst resection. In conclusion, it is not difficult to distinguish between ganglion cysts and ligamentum flavum cysts from preoperative MRI findings. Especially for ligamentum flavum cysts, most parts of the cysts are solid, and CT-guided cyst aspiration will not reduce the mass of the cyst that compresses the spinal cord. In addition, if the cyst has strong adhesion to the surrounding tissues, it makes the resection surgery more difficult. Therefore, accurate preoperative MRI differentiation of ligamentum flavum cysts from other kinds of cysts is important for selection of a treatment option (conservative, minimally invasive CT-guided aspiration, or surgery) and an appropriate surgical plan.
Conflict of interest The authors declare that they have no conflict of interest.
Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004
H. Saiwai et al. / Journal of Orthopaedic Science xxx (2015) 1e5
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Please cite this article in press as: Saiwai H, et al., Clinical features and surgical management of rare cases of thoracic intraspinal cysts: Report of 3 cases, Journal of Orthopaedic Science (2015), http://dx.doi.org/10.1016/j.jos.2015.09.004