Acute celiac artery compression syndrome after extensive correction of sagittal balance on an adult spinal deformity.

PURPOSE: To describe the first case of a patient who developed acute celiac artery compression syndrome (ACACS) after extensive correction of sagittal balance on an adult spinal deformity. METHODS: A 77-year-old woman presented with low back pain and spinal kyphosis deformity. We performed a two-stage correction with extreme lateral interbody fusion (XLIF), and her lumbar lordosis improved from -47° to 53°. However, after surgery, she experienced frequent vomiting and diarrhea. Contrast-enhanced computed tomography showed marked narrowing of the abdominal aorta at the L1/2 level, and both the celiac artery and superior mesenteric artery were compressed. Therefore, emergency surgery was performed. After laparotomy, we found that the small bowel exhibited an unfavorable color and that peristalsis had stopped. The aorta was compressed from the anterior direction at the upper side of the renal arteries. The median arcuate ligament (MAL) and celiac plexus were responsible for the compression. After the compression was relieved, the small bowel color and peristaltic activity improved. RESULTS: Postoperatively, there was no recurrence of abdominal symptoms. The patient could walk with a walking frame from 3 weeks postoperatively. CONCLUSION: ACACS is a life-threatening complication, and therefore, it is very important that ACACS is diagnosed and treated early. Spinal deformity surgeons should be aware of the possible occurrence of this condition after extensive correction of sagittal balance on adult spinal deformity.

Dynamic paraspinal muscle impingement causing acute hemiplegia after C1 posterior arch laminectomy: A case report.

RATIONALE: Acute neurological deficits following spinal surgery commonly result from epidural hematoma, surgical trauma, vascular compromise, and graft or hardware impingement, with the cause identified by magnetic resonance imaging (MRI). We present a rare case of dynamic paraspinal muscle impingement after C1 posterior arch laminectomy, which was diagnosed by myelography, with no significant findings on MRI. PATIENT CONCERNS: An 81-year-old, severely obese male, was referred to our department for the treatment of vertebral disease of the lumbar spine. The patient presented with bilateral weakness and numbness of the upper extremities and gait disturbances. Based on MRI, a diagnosis of retro-odontoid pseudotumor was made, and C1 posterior arch laminectomy, in combination with C4 partial laminectomy and C5 to C6 laminoplasty, was performed. On postoperative day 3, the patient's neurological status deteriorated, with right upper extremity and right lower extremity weakness increasing with neck extension. Although there was no evidence of epidural hematoma formation on MRI, obstruction of the flow of contrast medium by an external posterior compression in neck extension at the level of C1 was identified by myelography. Revision surgery was performed and local muscle swelling at the surgical site identified with no hematoma formation. Occiput to C3 fixation, with instrumentation, was performed. OUTCOMES: Muscle strength of the right upper extremity and lower extremities recovered postsurgery, and the patient has continued to improve function 3 years after surgery, with no further neurological episodes. LESSONS: Dynamic paraspinal muscle impingement following C1 laminectomy in a muscular man was diagnosed by myelography, with no significant findings on standard MRI. CONCLUSION: The possibility of dynamic paraspinal muscle impingement should be considered in patients developing acute, progressive, neurological deficits after posterior cervical decompression, with myelography being the imaging method of choice for diagnosis.

Analysis of the Relationship between Ligamentum Flavum Thickening and Lumbar Segmental Instability, Disc Degeneration, and Facet Joint Osteoarthritis in Lumbar Spinal Stenosis.

STUDY DESIGN: Cross-sectional study. PURPOSE: To investigate the relationship between ligamentum flavum (LF) thickening and lumbar segmental instability and disc degeneration and facet joint osteoarthritis. OVERVIEW OF LITERATURE: Posterior spinal structures, including LF thickness, play a major role in lumbar spinal canal stenosis pathogenesis. The cause of LF thickening is multifactorial and includes activity level, age, and mechanical stress. LF thickening pathogenesis is unknown. METHODS: We examined 419 patients who underwent computed tomography (CT) myelography and magnetic resonance imaging after complaints of clinical symptoms. To investigate LF hypertrophy, 57 patients whose lumbar vertebra had normal disc heights at L4-5 were selected to exclude LF buckling as a hypertrophy component. LF thickness, disc space widening angulation in flexion, segmental angulation, presence of a vacuum phenomenon, and lumbar lordosis at T12-S1 were investigated. Disc and facet degeneration were also evaluated. Facet joint orientation was measured via an axial CT scan. RESULTS: The mean LF thickness in all patients was 4.4±1.0 mm at L4-5. There was a significant correlation between LF thickness and disc degeneration; LF thickness significantly increased with severe disc degeneration and facet joint osteoarthritis. There was a tendency toward increased LF thickness in more sagittalized facet joints than in coronalized facet joints. Logistic regression analysis showed that LF thickening was influenced by segmental angulation and facet joint osteoarthritis. Patient age was associated with LF thickening. CONCLUSIONS: LF hypertrophy development was associated with segmental instability and severe disc degeneration, severe facet joint osteoarthritis, and a sagittalized facet joint orientation.

Tuberculous Spondylitis following Intravesical Bacillus Calmette-Guerin for Bladder Cancer.

We present a rare case of tuberculous spondylitis following intravesical Bacillus Calmette-Guerin (BCG) therapy for bladder cancer. An 82-year-old man presented with low back pain. Past medical history revealed bladder cancer diagnosed and treated 16 months previously by intravesical BCG. Magnetic resonance imaging of the thoracic spine showed destruction of the T5 and T6 vertebrae and an epidural soft tissue mass with anterior dural sac compression. Due to the progression of vertebral destruction, posterior spinal segmental fusion was performed. Mycobacterium bovis (M. bovis) was identified using multiplex polymerase chain reaction of surgical tissue specimens. The patient was started on an antituberculosis treatment regimen including isoniazid, rifampicin, and ethambutol. After surgery, his back pain resolved completely. At the latest examination, the patient was pain-free with no functional limitations or recurrent infection in clinical or imaging findings. Patients undergoing BCG therapy should be monitored for possible hematogenous spread of mycobacteria to the spine for months or even years after treatment.

Analysis of the Relationship between Hypertrophy of the Ligamentum Flavum and Lumbar Segmental Motion with Aging Process.

STUDY DESIGN: Retrospective cross-sectional study. PURPOSE: To investigate the relationship between ligamentum flavum (LF) hypertrophy and lumbar segmental motion. OVERVIEW OF LITERATURE: The pathogenesis of LF thickening is unclear and whether the thickening results from tissue hypertrophy or buckling remains controversial. METHODS: 296 consecutive patients underwent assessment of the lumbar spine by radiographic and magnetic resonance imaging (MRI). Of these patients, 39 with normal L4-L5 disc height were selected to exclude LF buckling as one component of LF hypertrophy. The study group included 27 men and 12 women, with an average age of 61.2 years (range, 23-81 years). Disc degeneration and LF thickness were quantified on MRI. Lumbar segmental spine instability and presence of a vacuum phenomenon were identified on radiographic images. RESULTS: The distribution of disc degeneration and LF thickness included grade II degeneration in 4 patients, with a mean LF thickness of 2.43±0.20 mm; grade III in 10 patients, 3.01±0.41 mm; and grade IV in 25 patients, 4.16±1.12 mm. LF thickness significantly increased with grade of disc degeneration and was significantly correlated with age (r=0.55, p<0.01). Logistic regression analysis identified predictive effects of segmental angulation (odds ratio [OR]=1.55, p=0.014) and age (OR=1.16, p=0.008). CONCLUSIONS: Age-related increases in disc degeneration, combined with continuous lumbar segmental flexion-extension motion, leads to the development of LF hypertrophy.

Pyogenic vertebral osteomyelitis caused by Yersinia pseudotuberculosis.

Septic vertebral osteomyelitis caused by Yersinia pseudotuberculosis is extremely rare. We report the first case of pyogenic vertebral osteomyelitis due to Y. pseudotuberculosis. A 65-year-old man presented with low back pain and fever. He had a history of psoriasis vulgaris treated with adalimumab. The patient reported drinking adequate amounts of well water daily. Clinical examination revealed no neurological deficit of the lower limbs. Laboratory findings included increased inflammatory reactions. Magnetic resonance imaging showed diffuse changes in intensity at the T10 and L3 vertebrae, and multiple nodular lesions in the thoracic, lumbar, sacral, and iliac regions. We performed an open biopsy. Y. pseudotuberculosis was cultured from both the T10 and L3 vertebrae lesions. Y. pseudotuberculosis is sensitive to almost all antibiotics. After initiating antibiotic treatment, the laboratory parameters normalized and the patient recovered completely, without any neurological deficits. To our knowledge, our report represents the first case of pyogenic vertebral osteomyelitis due to Y. pseudotuberculosis.

Prevalence and distribution of thoracic and lumbar compressive lesions in cervical spondylotic myelopathy.

STUDY DESIGN: Retrospective cross-sectional study. PURPOSE: This study analyzed the prevalence and distribution of horacic and lumbar compressive lesions in cervical spondylotic myelopathy as well as their relationships with cervical developmental spinal canal stenosis (DCS) by using whole-spine postmyelographic computed tomography. OVERVIEW OF LITERATURE: There are few studies on missed compressive lesions of the spinal cord or cauda equina at the thoracolumbar level in cervical spondylotic myelopathy. Furthermore, the relationships between DCS, and the prevalence and distribution of thoracic and lumbar compressive lesions are unknown. METHODS: Eighty patients with symptomatic cervical spondylotic myelopathy were evaluated. Preoperative image data were obtained. Patients were classified as DCS or non-DCS (n=40 each) if their spinal canal longitudinal diameter was <12 mm at any level or ≥12 mm at all levels, respectively. Compressive lesions in the anterior and anteroposterior parts, ligamentum flavum ossification, posterior longitudinal ligament ossification, and spinal cord tumors at the thoracolumbar levels were analyzed. RESULTS: Compressive lesions in the anterior and anteroposterior parts were observed in 13 (16.3%) and 45 (56.3%) patients, respectively. Ligamentum flavum and posterior longitudinal ligament ossification were observed in 19 (23.8%) and 3 (3.8%) patients, respectively. No spinal cord tumors were observed. Thoracic and lumbar compressive lesions of various causes tended to be more common in DCS patients than non-DCS patients, although the difference was statistically insignificant. CONCLUSIONS: Surveying compressive lesions and considering the thoracic and lumbar level in cervical spondylotic myelopathy in DCS patients are important for preventing unexpected neurological deterioration and predicting accurate neurological condition after cervical surgery.

Enhancement of the effects of exfoliated carbon nanofibers by bone morphogenetic protein in a rat femoral fracture model.

Exfoliated carbon nanofibers (ExCNFs) are expected to serve as excellent scaffolds for promoting and guiding bone-tissue regeneration. We aimed to enhance the effects of ExCNFs with bone morphogenetic proteins (BMPs) and examine their feasibility and safety in clinical applications using a rat femoral fracture model. Group I (n = 16) animals were implanted with control MedGEL. Group II (n = 17) animals were implanted with MedGEL containing ExCNFs. Group III (n = 15) animals were implanted with MedGEL containing 1 µg rhBMP-2. Group IV (n = 15) animals were implanted with MedGEL containing 1 µg rhBMP-2 and ExCNFs. The rats were euthanized after 6 weeks, and their fractured femurs were explanted and assessed by manual palpation, radiographs, and high-resolution microcomputerized tomography (micro-CT); the femurs were also subjected to biomechanical and histological analysis. The fusion rates in Group IV (73.3%) were considerably higher than those in Groups I (25.0%), II (52.9%), and III (46.7%). The results demonstrated the enhancement of the bone repair effects of ExCNFs by BMP in a rat femoral fracture model. Our results suggest that the enhancement of the effects of ExCNFs by BMP makes the combination a possible attractive therapy for various orthopedic surgeries.

Predictable imaging signs of cauda equina entrapment in thoracolumbar and lumbar burst fractures with greenstick lamina fractures.

STUDY DESIGN: A retrospective study. PURPOSE: The aim of present study was to investigate imaging findings suggestive of cauda equina entrapment in thoracolumbar and lumbar burst fractures. OVERVIEW OF LITERATURE: Burst fractures with cauda equina entrapment can cause neurologic deterioration during surgery. However, dural tears and cauda equina entrapment are very difficult to diagnose clinically or radiographically before surgery. METHODS: Twenty-three patients who underwent spinal surgery for thoracolumbar or lumbar burst fractures were enrolled in this study. In magnetic resonance imaging T2-weighted images of the transverse plane, we defined cauda equina notch sign (CENS) as a v-shaped image that entrapped cauda equina gathers between lamina fractures. We evaluated the fractured spine by using CENS and lamina fractures and the rate of available space for the spinal canal at the narrowest portion of the burst fracture level. We classified patients into entrapment group or non-entrapment group, based on whether cauda equina entrapment existed. RESULTS: Lamina fractures were detected in 18 (78.3%) and CENS were detected in 6 (26.1%) of 23 burst-fracture patients. Cauda equina entrapment existed in all the patients with CENS. In addition, the rate of available space for the spinal canal increased according to logistic regression. The size of the retropulsed fragment in the spinal canal was the most reliable of all the factors, suggesting cauda equina entrapment. CONCLUSIONS: CENS was the most predictable sign of cauda equina entrapment associated with burst fractures.

Analysis of the prevalence and distribution of cervical and thoracic compressive lesions of the spinal cord in lumbar degenerative disease.

STUDY DESIGN: Retrospective study. PURPOSE: The aim of the present study is to analyze the prevalence and distribution of cervical and thoracic compressive lesions of the spinal cord in lumbar degenerative disease, using whole-spine postmyelographic computed tomography. OVERVIEW OF LITERATURE: Of the various complications resulting from spinal surgery, unexpected neurological deterioration is the most undesired. There are reports of missed compressive lesions of the spinal cord at the cervical or thoracic level in lumbar degenerative disease. METHODS: There were 145 consecutive patients with symptomatic lumbar degenerative disease evaluated. Before the lumbar surgery, image data were obtained. The following parameters at the cervical and thoracic levels were analyzed: compressive lesions from the anterior parts; compressive lesions from the anterior and posterior parts; ossification of the ligamentum flavum; ossification of the posterior longitudinal ligament; and spinal cord tumor. RESULTS: Compressive lesions from the anterior parts were observed in 34 cases (23.4%). Compressive lesions from the anterior and posterior parts were observed in 34 cases (23.4%). Lesions of ossification of the ligamentum flavum were observed in 45 cases (31.0%). Lesions of ossification of the posterior longitudinal ligament were observed in 15 cases (10.3%). Spinal cord tumor was not observed. CONCLUSIONS: A survey of compressive lesions at the cervical or thoracic level in lumbar degenerative disease is important in preventing unexpected neurological deterioration after the lumbar surgery.

Symptomatic spinal cord kinking due to focal adhesive arachnoiditis, with ossification of the ligamentum flavum: a case report.

STUDY DESIGN: A case report. OBJECTIVE: To describe a rare case of symptomatic spinal cord kinking due to focal adhesive arachnoiditis, with ossification of the ligamentum flavum (OLF). SUMMARY OF BACKGROUND DATA: Spinal cord kinking without spinal surgery is rare, and symptomatic spinal cord kinking due to focal adhesive arachnoiditis, with OLF is even rarer. METHODS: A 66-year-old female presented with numbness of the lower extremities and subsequently experienced gait disturbance due to motor weakness. Magnetic resonance imaging of the thoracic spine showed anterior displacement and kinking of the spinal cord from T11 to T12. Laminectomy and OLF resection were performed. The arachnoid membrane at the affected part was markedly thick and seemed cloudy. Adhesiolysis for arachnoid adhesion and release of spinal kinking were performed. RESULTS: She could walk with a cane 6 months postoperatively. One year postoperatively, thoracic computed tomography-myelography showed that the cord was repositioned in the dural sac, and that release of the spinal cord kink was maintained. CONCLUSION: Symptomatic spinal cord kinking due to focal adhesive arachnoiditis, with OLF is a rare clinical condition. It was difficult to diagnose the precise pathology of the spinal cord before surgery. Microsurgical arachnoidolysis resolved the spinal cord kinking, and no recurrence was noted within the follow-up period. LEVEL OF EVIDENCE: N/A.

Manipulation of anabolic and catabolic responses with bone morphogenetic protein and zoledronic acid in a rat spinal fusion model.

Bone fusion involves a complex set of regulated signaling pathways that control the formation of new bone matrix and the resorption of damaged bone matrix at the surgical site. It has been reported that systemically administering a single dose of zoledronic acid (ZA) at the optimal time increases the strength of the bone morphogenetic protein (BMP)-mediated callus. In the present study, we aimed to investigate the effect of BMP-2 and ZA in a rat spinal model. Sixty-seven rats were divided into 6 groups: group I (n=11) animals were implanted with a carrier alone, group II (n=12) animals were implanted with a carrier and a subcutaneous injection of ZA was administered 2weeks after surgery, group III (n=12) animals were implanted with a carrier containing 1µg of rhBMP-2, group IV (n=12) animals were implanted with a carrier containing 1µg of rhBMP-2 and a subcutaneous injection of ZA was administered 2weeks after surgery, group V (n=10) animals were implanted with a carrier containing 3µg of rhBMP-2, and group VI (n=10) animals were implanted with a carrier containing 3µg of rhBMP-2 and a subcutaneous injection of ZA was administered 2weeks after surgery. The rats were euthanized after 6weeks, and their spines were explanted and assessed by manual palpation, radiography, high-resolution micro-computerized tomography (micro-CT), and histologic analysis. The fusion rates in group VI (60%) were considerably higher than those in the groups I (0%), II (0%), III (12.5%), IV (20.8%), and V (35%), (P<0.05). Additionally, the radiographic scores of group VI were higher than those in the other groups, (P<0.05). In micro-CT analysis, the tissue and bone volumes of the callus were significantly higher in group VI than those in the other groups, (P<0.05). The trabecular number was significantly higher and the trabecular spacing was significantly lower in group VI than those in the other groups, (P<0.05). The combination of rhBMP-2 and ZA administered systemically as a single dose at the optimal time was efficacious in our rat spinal fusion model. Our results suggest that this combination facilitates spinal fusion and has potential clinical application.

Clinical features of cervical pyogenic spondylitis and intraspinal abscess.

STUDY DESIGN: Retrospective study. OBJECTIVES: The purpose of the present study was to elucidate the clinical features of cervical pyogenic spondylitis and intraspinal abscess and to use this knowledge for early diagnosis and treatment. SUMMARY OF BACKGROUND DATA: Cervical pyogenic spondylitis and intraspinal abscess are relatively rare diseases in which accurate diagnosis is difficult at early stage. However, because both diseases can cause severe paralysis and vital crisis at advanced stages, early diagnosis and treatment are very important. METHODS: Fourteen patients (men: 9, women: 5; average age at treatment: 65.4 y; age range: 49-89 y) with cervical pyogenic spondylitis and/or intraspinal abscess were treated in our hospital. We analyzed their initial symptoms, initial diagnosis, duration between the appearance of initial symptoms and final diagnosis, symptoms at final diagnosis, level of the affected cervical spine, predisposing factors, organisms, and treatments. RESULTS: Initial symptoms included neck pain with fever (n=7), neck pain without fever (n=3), pharyngeal pain with fever (n=1), muscle weakness in both the upper and lower extremities (n=1), gait disturbance (n=1), and numbness of the lower extremities (n=1). Patients were initially diagnosed with meningitis (n=4), fever of unknown origin (n=2), cervical spondylosis (n=2), polymyalgia rheumatica (n=1), upper respiratory tract inflammation (n=1), metastatic spinal tumor (n=1), cervical spondylotic myelopathy (n=1), and cervical disc herniation (n=1). Of the 14 patients, 1 was correctly diagnosed with cervical pyogenic spondylitis. CONCLUSIONS: The initial symptoms of cervical pyogenic spondylitis and intraspinal abscess varied and neck pain with fever was not essential. Therefore, doctors should consider the possibility of cervical pyogenic spondylitis and repeat the assessments of the clinical examination for early diagnosis of this disease.

Manipulation of the anabolic and catabolic responses with BMP-2 and zoledronic acid in a rat femoral fracture model.

Bone repair involves a complex set of regulated signaling pathways that control the formation of new bone matrix and the resorption of damaged bone matrix at the fracture site. It has been reported that the optimal time point for single-dose zoledronic acid (ZA) administration systemically increased the strength of bone morphogenetic protein (BMP)-7-mediated callus. However, its repair mechanism during bone fracture healing remains unknown. We aimed to investigate the synergic effect of recombinant human (rh) BMP-2 and ZA in a rat femoral fracture model. Fifty-eight rats were divided into 4 groups. Group I (n=14) animals were implanted with a carrier alone. Group II (n=15) animals were implanted with a carrier containing 1-µg rhBMP-2. Group III (n=14) animals were implanted with a carrier and a subcutaneous systemic ZA injection 2 weeks after surgery. Group IV (n=15) animals were implanted with a carrier containing 1-µg rhBMP-2 and ZA subcutaneous injection 2 weeks after surgery. The rats were euthanized after 6 weeks and their fractured femurs were explanted and assessed by manual palpation, radiographs, and high-resolution micro-computerized tomography (micro-CT) and were subjected to biomechanical and histological analysis. The fusion rates in Group IV (93.3%) were considerably higher than those in Groups I (28.6%), II (53.3%), and III (57.1%). Additionally, the radiographic scores of Group IV were higher than those in Groups I, II, and III. In micro-CT analysis, the tissue volume (TV) of the callus was higher in Group IV than in Groups I and II (p<0.05). New bone volume (BV) and trabecular spacing (Tb.Sp) also showed essentially the same trend as that of TV. The ratio of BV to TV (BV/TV), the trabecular number (Tb.N), and the trabecular thickness (Tb.Th) was higher in Groups III and IV than in Groups I and II (p<0.05). In biomechanical analysis, the ultimate loads at failure and stiffness in Groups III and IV were on average higher than those in Groups I and II (p<0.05), while the energy absorption of Group IV was higher than those of Groups I and II (p<0.05). The synergic effect of rhBMP-2 and ZA given systemically as a single dose at the optimal time was efficacious for fracture repair and significantly enhanced bone fusion. Our results suggest that this combination facilitates bone healing and has potential clinical application.

Analysis of measured D-dimer levels for detection of deep venous thrombosis and pulmonary embolism after spinal surgery.

STUDY DESIGN: A retrospective clinical study. OBJECTIVES: To show the prevalence of deep venous thrombosis (DVT) and pulmonary embolism (PE) after spinal surgery using a D-dimer assay followed by screening with computed tomographic (CT) pulmonary angiography and CT venography. SUMMARY OF BACKGROUND DATA: A few studies on DVT development after spinal surgery have been reported. METHODS: A complete surveillance examination for DVT and PE was conducted in 88 patients who underwent spinal surgery [male patients, 48; female patients, 40; average age at operation, 62.4 y (range, 17 to 85 y)] through a D-dimer assay combined with CT pulmonary angiography and CT venography. The operation levels were the cervical spine (21 cases), the thoracic spine (16 cases), and the lumbar spine (51 cases). We adopted a D-dimer cut-off point of 10 µg/mL, and classified the patients into high D-dimer (HD; D-dimer level ≥10 µg/mL) and low D-dimer (LD; D-dimer level <10 µg/mL) groups. RESULTS: Nine (10.2%) patients showed D-dimer levels of ≥10 µg/mL (HD group); of these, 5 patients (5.7%) had DVT. Two (2.2%) of the 5 DVT patients had PE. DVT was evident in 1 (6.2%) of the 16 patients who underwent thoracic procedures and 4 (7.8%) of the 51 patients who underwent lumbar procedures. Statistical comparison between the HD (excluding 5 patients with DVT or PE) and LD groups showed a significant difference in intraoperative blood loss between the groups (P=0.02). CONCLUSIONS: The D-dimer assay was useful in predicting DVT development. A D-dimer level of ≥10 µg/mL is considered to be a risk factor for thromboembolic disease after spinal surgery. False-positive cases of thromboembolic disease preclude the use of this assay as a stand-alone test for DVT diagnosis. CT venography and CT pulmonary angiography are recommended to confirm thromboembolic disease.

Morphological analysis of the cervical pedicles, lateral masses, and laminae in developmental canal stenosis.

STUDY DESIGN: Retrospective cross-sectional study. OBJECTIVE: This study aimed to elucidate the relationship between developmental spinal canal stenosis (DCS) and morphologic features in the cervical spine by comparing the features between DCS and nondevelopmental spinal canal stenosis (NDCS). SUMMARY OF BACKGROUND DATA: DCS is an important predisposing factor for cervical myelopathy. Further, various posterior cervical spinal instrumentations have been developed. However, no study has specifically addressed the cervical posterior morphology of DCS. METHODS: A total of 52 consecutive patients underwent cervical spine computed tomography myelography. Axial images of the largest pedicle diameter were selected from C3 to C7 vertebrae and 260 images were analyzed. The following parameters were measured: spinal canal longitudinal diameter (SCLD), spinal canal transverse diameter, osseous spinal canal area, dural sac area, spinal cord area, pedicle outer width, pedicle axis length, pedicle transverse angulation, lateral mass longitudinal diameter, lateral mass transverse diameter, lamina outer width, and lamina axis length. The participants were classified into 2 groups: DCS group (SCLD <12 mm at any level) and NDCS group (SCLD ≧12 mm at all levels). RESULTS: The mean osseous spinal canal area and dural sac area at C3-C5 in the DCS group were less than those in the NDCS group. The mean spinal cord area did not differ significantly at C3-C7 between the groups. The mean pedicle outer width at C6 and C7 in the DCS group was less than that in NDCS group. The mean lateral mass transverse diameter at C5 and mean lateral mass longitudinal diameter at C3, C5, and C6 in the DCS group were less than those in the NDCS group. CONCLUSION: Myelopathy is expected to progress in patients with DSC and these patients with severe neurologic symptoms may need cervical operation. However, posterior screw insertions should be considered more carefully than in NDCS patients.

Analysis of the relationship between facet joint angle orientation and lumbar spine canal diameter with respect to the kinematics of the lumbar spinal unit.

STUDY DESIGN: Retrospective cross-sectional study. OBJECTIVE: This study aimed to elucidate the relationship among facet orientation, kinematics of a spinal unit, and change in lumbar spine canal diameter by using kinetic magnetic resonance imaging. SUMMARY OF BACKGROUND DATA: Some studies have suggested an association between increased sagittally oriented facet angles and degenerative lumbar spondylolisthesis. However, no study has specifically addressed the association of facet orientation with the kinematics of a spinal unit and change in canal diameter. METHODS: Kinetic magnetic resonance imagings were performed with patients in flexion, neutral, and extension positions. Study subjects were classified into 6 groups-AA, BB, CC, AB (BA), BC (CB), and AC (CA)-on the basis of bilateral facet angles (A, narrow; B, normal; and C, wide) and disc and facet joint degeneration. A magnetic resonance imaging analyzer was used for anatomic measurements and for calculating changes in canal diameters and disc bulging as well as the lumbar spine kinematics. RESULTS: Osseous canal diameters were significantly smaller in the group AA than in the group BB, whereas they were significantly larger in the group CC than in the group BB. Canal diameter at the disc level was significantly smaller in the group AA than in the group BB in all 3 positions, whereas it was significantly larger in the group CC than in the group BB. Translational motion was significantly more in the group AA than in the group BB, whereas it was significantly lesser in the group CC than in the group BB. CONCLUSIONS: We demonstrated the relationship among facet orientation, osseous canal diameter, kinematics of a spinal unit, and change in lumbar spine canal diameter. Patients with sagittally oriented facets had narrow osseous canals with mobility, whereas those with coronally oriented facets had stable and wider osseous canals. This finding is helpful in understanding the mechanism underlying lumbar spinal canal stenosis and degenerative spondylolisthesis.