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T1–2 disc herniation following an en bloc cervical laminoplasty
J Orthop Sci (2002) 7:495–497
Case reports T1–2 disc herniation following an en bloc cervical laminoplasty Hiroshi Takagi, Yoshiharu Kawaguchi, Masahiko Kanamori, Yumiko Abe, and Tomoatsu Kimura Department of Orthopaedic Surgery, Toyama Medical and Pharmaceutical University, Faculty of Medicine, 2630 Sugitani, Toyama 930-0194, Japan
Abstract We report a rare case of T1–2 disc herniation following cervical laminoplasty. A 56-year-old male patient presented with left foot-drop and gait disturbance of abrupt onset 11 years after a successful laminoplasty from C3–7. Magnetic resonance imaging revealed spinal stenosis at T1–2 due to intervertebral disc herniation and ligamentum flavum hypertrophy. Three days later, laminectomy with disc fragment excision was performed at that level. Two weeks after surgery, he was able to walk without assistance. Mechanical stresses may have directly affected the T1–2 intervertebral disc following laminoplasty and may have caused disc herniation. Key words Thoracic disc herniation · Thoracic spine · En bloc laminoplasty
Introduction Thoracic disc herniations are uncommon, and high thoracic disc herniations are rare.1,10 We report the case of a T1–2 thoracic disc herniation immediately below a cervical laminoplasty and evaluate the factors that may have contributed to the resultant neurological disability.
Case report In 1988, cervical spondylotic myelopathy was diagnosed in a 56-year-old male patient who presented with gait disturbance and right hand weakness. Preoperative magnetic resonance imaging (MRI) showed spinal cord
compression at the C5–T1 levels. En bloc laminoplasty from C3–7, as described by Itoh and Tsuji,6 was performed (Fig. 1), and his symptoms disappeared completely following surgery. From March 1999, he complained of a feeling of constriction in his umbilical region, bilateral buttock pain on walking, and motor weakness in both legs. Left foot-drop developed abruptly 2 weeks after the onset of the initial symptoms. Physical examination revealed absence of deep tendon reflexes in both legs, paralysis of the left leg, and hypalgesia below the T4 level, predominantly on the left side. Vibration sense and proprioception were also diminished in the left leg. Sphincter tonus and perianal sensation were reduced. A diagnosis of transverse-type paraparesis due to compression at the level of the upper thoracic spinal cord was made. Radiographs revealed continued enlargement of the cervical spinal canal, but progression of osteophyte formation at the anterior vertebrae of C4–T1 was observed (Fig. 1). The postoperative range of motion (ROM) of the cervical spine was reduced to 30% of the preoperative ROM. MRI showed spinal cord compression by a large left paramedian disc herniation and hypertrophy of the ligamentum flavum at the T1–2 level (Fig. 2a and b). T1–2 laminectomy and posterior disc fragment excision were performed 3 days after the occurrence of his inability to walk. The spinal cord was displaced by sequestrated disc fragments. The specimen showed severe degeneration. The patient was able to walk without any assistance within 2 weeks and returned to his sedentary job 2 months after surgery.
Discussion Offprint requests to: Y. Kawaguchi Received: October 17, 2001 / Accepted: February 1, 2002
Arce and Dohman reported that disc herniation in the thoracic spine is uncommon compared with herniation
496
H. Takagi et al.: Thoracic disc herniation following cervical laminoplasty
in the cervical and lumbar spine.1 In thoracic disc herniation, the upper third of the thoracic spine is the least affected area. The rate of occurrence in the upper third is reported to be 6% of thoracic disc herniations, whereas the rate is 66% in the lower third and 28% in the middle third.1 Morgan and Abood reported the precise clinical features of four cases with T1–2 disc herniation and reviewed the literature of upper thoracic disc herniation.10
a,b Fig. 1. a Plain radiography just after laminoplasty. b Plain radiography 11 years after laminoplasty. The sagittal diameter of the spinal canal remained enlarged, and progression of osteophyte formation at the anterior vertebrae of C4–T1 was observed after laminoplasty
a
On the other hand, although satisfactory surgical outcomes have been reported following various types of laminoplasty,2–9,11–14 late functional deterioration has been reported in some cases.5,8,9,12 The causes of deterioration were reported to be age over 60 years, decreased sagittal diameter of the spinal canal, progression of ossification of the posterior longitudinal ligament (OPLL), and malalignment of the cervical spine. Other spinal lesions, such as thoracic OPLL and lumbar spinal stenosis, can cause such deterioration.12 In our study of cases with a minimum 10-year follow-up after cervical laminoplasty, the causes of neurological deterioration were severe kyphosis of the cervical spine, progression of OPLL, lumbar spinal stenosis, cerebral infarction, and diabetic neuropathy. However, we have not found any case report of neurological deterioration due to thoracic disc herniation adjacent to an earlier cervical laminoplasty. In the case reported here, mechanical stresses may have directly affected the T1–2 intervertebral disc following laminoplasty. The ROM of the cervical spine decreases after laminoplasty.3,4,6,8,12,13 In this case, the postoperative ROM was reduced to 30% of the preoperative ROM, and osteophyte formation was observed at the C4–5, 5–6, 6–7, and C7–T1 levels (Fig. 1). Mechanical stresses to the upper thoracic spine are thought to develop in compensation for the decreased ROM of the cervical spine. The hypertrophy of the ligamentum flavum at the T1–2 level that was observed in the postoperative MRI (Fig. 2) most likely resulted from these increased stresses. Therefore, in long-term follow-up studies, particular attention should be paid to pathological changes at the lower level adjacent to the cervical laminoplasty.
b
Fig. 2. a MRI T2-weighted sagittal image showing deformation of the spinal cord from anterior and posterior compressive factors at the T1–2 level (arrows). b MRI T2weighted axial image showing a large disc herniation at the left side and hypertrophy of the ligamentum flavum
H. Takagi et al.: Thoracic disc herniation following cervical laminoplasty
References 1. Arce CA, Dohrmann GJ. Herniated thoracic disks. Neurology 1985;3:383–92. 2. Fukui K, Kataoka O, Sho T, et al. Pathomechanism, pathogenesis, and results of treatment in cervical spondylotic myelopathy caused by dynamic canal stenosis. Spine 1990;15:1148–52. 3. Hase H, Watanabe T, Hirasawa Y, et al. Bilateral open laminoplasty using ceramic laminae for cervical myelopathy. Spine 1991;16:1269–76. 4. Hirabayashi K, Satomi K. Operative procedure and results of expansive open-door laminoplasty. Spine 1988;13:870–6. 5. Hirabayashi K. Expansive open-door laminoplasty; its present state of the art and future prospects. Rinsho Seikei Geka 1995; 30:543–8 (in Japanese). 6. Itoh T, Tsuji H. Technical improvements and results of laminoplasty for compressive myelopathy in the cervical spine. Spine 1985;10:729–36. 7. Kamioka Y, Yamamoto H, Tani T, et al. Postoperative instability of cervical OPLL and cervical radiculopathy. Spine 1989;14:1177– 83.
497
8. Kawai S, Sunago K, Doi K, et al. Cervical laminoplasty (Hattori’s Method) procedure and follow-up results. Spine 1988;13:1245– 50. 9. Kimura I, Shingu H, Nasu Y, et al. Long-term follow-up of cervical spondylotic myelopathy treated by canal-expansive laminoplasty. J Bone Joint Surg Br 1995;77:956–61. 10. Morgan H, Abood C. Disc herniation at T1–2. Report of four cases and literature review. J Neurosurg 1998;88:148–50. 11. Nakano N, Nakano T, Nakano K. Comparison of the results of laminectomy and open-door laminoplasty for cervical spondylotic myeloradiculopathy and ossification of the posterior longitudinal ligament. Spine 1988;13:792–4. 12. Satomi K, Nishu Y, Kohno T, et al. Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy. Spine 1994;19:507–10. 13. Yonenobu K, Yamamoto T, Ono K. Laminoplasty for myelopathy: indication, results, outcomes, and complication. In: Clark CR, editor. The cervical spine 3rd ed. Philadelphia: Lippincott-Raven; 1998. p. 849–64. 14. Yoshida M, Otani K, Shibasaki K, et al. Expansive laminoplasty with reattachment of spinous process and extensor musculature for cervical myelopathy. Spine 1992;17:491–7.
Case reports T1–2 disc herniation following an en bloc cervical laminoplasty Hiroshi Takagi, Yoshiharu Kawaguchi, Masahiko Kanamori, Yumiko Abe, and Tomoatsu Kimura Department of Orthopaedic Surgery, Toyama Medical and Pharmaceutical University, Faculty of Medicine, 2630 Sugitani, Toyama 930-0194, Japan
Abstract We report a rare case of T1–2 disc herniation following cervical laminoplasty. A 56-year-old male patient presented with left foot-drop and gait disturbance of abrupt onset 11 years after a successful laminoplasty from C3–7. Magnetic resonance imaging revealed spinal stenosis at T1–2 due to intervertebral disc herniation and ligamentum flavum hypertrophy. Three days later, laminectomy with disc fragment excision was performed at that level. Two weeks after surgery, he was able to walk without assistance. Mechanical stresses may have directly affected the T1–2 intervertebral disc following laminoplasty and may have caused disc herniation. Key words Thoracic disc herniation · Thoracic spine · En bloc laminoplasty
Introduction Thoracic disc herniations are uncommon, and high thoracic disc herniations are rare.1,10 We report the case of a T1–2 thoracic disc herniation immediately below a cervical laminoplasty and evaluate the factors that may have contributed to the resultant neurological disability.
Case report In 1988, cervical spondylotic myelopathy was diagnosed in a 56-year-old male patient who presented with gait disturbance and right hand weakness. Preoperative magnetic resonance imaging (MRI) showed spinal cord
compression at the C5–T1 levels. En bloc laminoplasty from C3–7, as described by Itoh and Tsuji,6 was performed (Fig. 1), and his symptoms disappeared completely following surgery. From March 1999, he complained of a feeling of constriction in his umbilical region, bilateral buttock pain on walking, and motor weakness in both legs. Left foot-drop developed abruptly 2 weeks after the onset of the initial symptoms. Physical examination revealed absence of deep tendon reflexes in both legs, paralysis of the left leg, and hypalgesia below the T4 level, predominantly on the left side. Vibration sense and proprioception were also diminished in the left leg. Sphincter tonus and perianal sensation were reduced. A diagnosis of transverse-type paraparesis due to compression at the level of the upper thoracic spinal cord was made. Radiographs revealed continued enlargement of the cervical spinal canal, but progression of osteophyte formation at the anterior vertebrae of C4–T1 was observed (Fig. 1). The postoperative range of motion (ROM) of the cervical spine was reduced to 30% of the preoperative ROM. MRI showed spinal cord compression by a large left paramedian disc herniation and hypertrophy of the ligamentum flavum at the T1–2 level (Fig. 2a and b). T1–2 laminectomy and posterior disc fragment excision were performed 3 days after the occurrence of his inability to walk. The spinal cord was displaced by sequestrated disc fragments. The specimen showed severe degeneration. The patient was able to walk without any assistance within 2 weeks and returned to his sedentary job 2 months after surgery.
Discussion Offprint requests to: Y. Kawaguchi Received: October 17, 2001 / Accepted: February 1, 2002
Arce and Dohman reported that disc herniation in the thoracic spine is uncommon compared with herniation
496
H. Takagi et al.: Thoracic disc herniation following cervical laminoplasty
in the cervical and lumbar spine.1 In thoracic disc herniation, the upper third of the thoracic spine is the least affected area. The rate of occurrence in the upper third is reported to be 6% of thoracic disc herniations, whereas the rate is 66% in the lower third and 28% in the middle third.1 Morgan and Abood reported the precise clinical features of four cases with T1–2 disc herniation and reviewed the literature of upper thoracic disc herniation.10
a,b Fig. 1. a Plain radiography just after laminoplasty. b Plain radiography 11 years after laminoplasty. The sagittal diameter of the spinal canal remained enlarged, and progression of osteophyte formation at the anterior vertebrae of C4–T1 was observed after laminoplasty
a
On the other hand, although satisfactory surgical outcomes have been reported following various types of laminoplasty,2–9,11–14 late functional deterioration has been reported in some cases.5,8,9,12 The causes of deterioration were reported to be age over 60 years, decreased sagittal diameter of the spinal canal, progression of ossification of the posterior longitudinal ligament (OPLL), and malalignment of the cervical spine. Other spinal lesions, such as thoracic OPLL and lumbar spinal stenosis, can cause such deterioration.12 In our study of cases with a minimum 10-year follow-up after cervical laminoplasty, the causes of neurological deterioration were severe kyphosis of the cervical spine, progression of OPLL, lumbar spinal stenosis, cerebral infarction, and diabetic neuropathy. However, we have not found any case report of neurological deterioration due to thoracic disc herniation adjacent to an earlier cervical laminoplasty. In the case reported here, mechanical stresses may have directly affected the T1–2 intervertebral disc following laminoplasty. The ROM of the cervical spine decreases after laminoplasty.3,4,6,8,12,13 In this case, the postoperative ROM was reduced to 30% of the preoperative ROM, and osteophyte formation was observed at the C4–5, 5–6, 6–7, and C7–T1 levels (Fig. 1). Mechanical stresses to the upper thoracic spine are thought to develop in compensation for the decreased ROM of the cervical spine. The hypertrophy of the ligamentum flavum at the T1–2 level that was observed in the postoperative MRI (Fig. 2) most likely resulted from these increased stresses. Therefore, in long-term follow-up studies, particular attention should be paid to pathological changes at the lower level adjacent to the cervical laminoplasty.
b
Fig. 2. a MRI T2-weighted sagittal image showing deformation of the spinal cord from anterior and posterior compressive factors at the T1–2 level (arrows). b MRI T2weighted axial image showing a large disc herniation at the left side and hypertrophy of the ligamentum flavum
H. Takagi et al.: Thoracic disc herniation following cervical laminoplasty
References 1. Arce CA, Dohrmann GJ. Herniated thoracic disks. Neurology 1985;3:383–92. 2. Fukui K, Kataoka O, Sho T, et al. Pathomechanism, pathogenesis, and results of treatment in cervical spondylotic myelopathy caused by dynamic canal stenosis. Spine 1990;15:1148–52. 3. Hase H, Watanabe T, Hirasawa Y, et al. Bilateral open laminoplasty using ceramic laminae for cervical myelopathy. Spine 1991;16:1269–76. 4. Hirabayashi K, Satomi K. Operative procedure and results of expansive open-door laminoplasty. Spine 1988;13:870–6. 5. Hirabayashi K. Expansive open-door laminoplasty; its present state of the art and future prospects. Rinsho Seikei Geka 1995; 30:543–8 (in Japanese). 6. Itoh T, Tsuji H. Technical improvements and results of laminoplasty for compressive myelopathy in the cervical spine. Spine 1985;10:729–36. 7. Kamioka Y, Yamamoto H, Tani T, et al. Postoperative instability of cervical OPLL and cervical radiculopathy. Spine 1989;14:1177– 83.
497
8. Kawai S, Sunago K, Doi K, et al. Cervical laminoplasty (Hattori’s Method) procedure and follow-up results. Spine 1988;13:1245– 50. 9. Kimura I, Shingu H, Nasu Y, et al. Long-term follow-up of cervical spondylotic myelopathy treated by canal-expansive laminoplasty. J Bone Joint Surg Br 1995;77:956–61. 10. Morgan H, Abood C. Disc herniation at T1–2. Report of four cases and literature review. J Neurosurg 1998;88:148–50. 11. Nakano N, Nakano T, Nakano K. Comparison of the results of laminectomy and open-door laminoplasty for cervical spondylotic myeloradiculopathy and ossification of the posterior longitudinal ligament. Spine 1988;13:792–4. 12. Satomi K, Nishu Y, Kohno T, et al. Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy. Spine 1994;19:507–10. 13. Yonenobu K, Yamamoto T, Ono K. Laminoplasty for myelopathy: indication, results, outcomes, and complication. In: Clark CR, editor. The cervical spine 3rd ed. Philadelphia: Lippincott-Raven; 1998. p. 849–64. 14. Yoshida M, Otani K, Shibasaki K, et al. Expansive laminoplasty with reattachment of spinous process and extensor musculature for cervical myelopathy. Spine 1992;17:491–7.