New Grading System for Cervical Paraspinal Soft Tissue Damage After Traumatic Cervical Spinal Cord Injury Without Major Fracture Based on the Short-T1 Inversion Recovery Mid-Sagittal MRI for Prediction of Neurological Improvements: The STIR-MRI Grade.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To develop a grading method for cervical paraspinal soft tissue damage after cervical spinal cord injury (CSCI) without major fracture based on the short T1 inversion recovery (STIR) mid-sagittal magnetic resonance image (MRI) for prediction of neurological improvements. METHODS: This study included 34 patients with CSCI without major fracture, treated conservatively for at least 1 year and graded using the STIR-MRI Grade. This system consists of anterior grades; A0: no high-intensity area (HIA), A1: linear HIA, and A2: fusiform HIA, and posterior grades; P0: no HIA, P1: HIA not exceeding the nuchal ligament, and P2: HIA exceeding the nuchal ligament, within 24 hours postinjury. The American Spinal Injury Association impairment scale (AIS) and the Japanese Orthopedic Association (JOA) scores were examined. RESULTS: Anterior grades were not significantly correlated with the AIS and JOA score. At both injury and final follow-up, the AIS in P2 patients was significantly more severe (P = 0.007, P = 0.015, respectively) than that in P0 patients. At the injury, the AIS in P2 patients was significantly more severe (P = 0.008) than that in P1 patients. Among P2 patients only, the JOA score at the injury (1.4 points) did not improve by the final follow-up (3.9 points). The final follow-up JOA score (3.9 points) in P2 patients was significantly lower than that (13.6 points) in P0 patients (P = 0.016). CONCLUSIONS: Grade P2 led to poor neurological outcomes. The STIR-MRI Grade is a prognostic indicator for neurological improvements past-CSCI.

Can prophylactic C4/5 foraminotomy prevent C5 palsy after cervical laminoplasty with and without posterior instrumented fusion with maximal expansion?

OBJECTIVE: To prospectively examine whether laminoplasty with maximal expansion induces C5 palsy, even with prophylactic bilateral C4/5 foraminotomy. METHODS: Thirty-five consecutive patients with cervical myelopathy underwent laminoplasty (n = 19: LP group) or posterior decompression and fusion (n = 16: PDF group) with maximal expansion. Prophylactic bilateral C4/5 foraminotomy was performed alternately in consecutive five patients undergoing each type of surgery. In each type of surgery, the first and third consecutive five patients did not undergo foraminotomy (NF subgroup: 20 patients), while the second and fourth consecutive five patients underwent foraminotomy (F subgroup: 15 patients). The widths between the gutters was equivalent to the diameter of the spinal canal, and an inclination angle of the lamina of approximately 90° was created during laminoplasty. The incidence and severity of postoperative C5 palsy were investigated. Patients with a manual muscle testing score for the deltoid muscle and/or biceps brachii muscle of ≤ 2 were diagnosed with severe palsy. RESULTS: The respective incidences of C5 palsy in the F and NF subgroups were 33% and 20% in the LP group and 50% and 20% in the PDF group. Severe palsy occurred in 67% and 0% of patients who had developed palsy in F and NF subgroups, respectively, in the LP group, and in 100% of patients in the PDF group. Furthermore, 40% of the patients with severe palsy took more than 6 months to recover. CONCLUSIONS: Laminoplasty with maximal expansion induced C5 palsy in both the LP and PDF groups, even with the addition of prophylactic bilateral C4/5 foraminotomy.

Fixed Neck Position in Multilevel Cervical Posterior Decompression and Fusion to Reduce Postoperative Disturbances of Cervical Spine Function.

INTRODUCTION: Difficulties with neck mobility often interfere with patients' activities of daily living (ADL) after cervical posterior spine surgery. The range of motion of the cervical spine decreases markedly after multilevel cervical posterior decompression and fusion (PDF). However, details regarding the limitations of cervical spine function due to postoperative reduced neck mobility after multilevel PDF are as yet unclarified. The present study aimed to clarify the quality of life and its related factors after PDF, and the optimal fixed neck position in multilevel PDF that minimizes the limitations of ADL accompanying markedly reduced postoperative neck mobility. METHODS: Limitations of ADL involving neck extension, rotation, and flexion were investigated in 32 consecutive patients who underwent C2-T1 PDF using the responses to the cervical spine function domain of the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). The EuroQol 5 Dimension, Japanese Orthopedic Association score, and five domains of the JOACMEQ were also investigated. We investigated the risk factors regarding the fixed neck position in PDF for the impossibility to perform ADL involving each of three movements using cut-off values obtained from receiver-operating characteristic curves. RESULTS: Postoperative comprehensive quality of life was significantly related to neurological improvements and to poor outcomes of cervical spine function after PDF. The significant risk factors for impossibility to perform ADL involving neck rotation were a C2-C7 lordotic angle ≥ 6° (P = 0.0057) or a proportion coefficient of C2-T1 tilt angle/C2-C7 lordotic angle ≤ 1.8 (P = 0.0024). There were no significant risk factors for impossibility to perform ADL involving neck extension or flexion. CONCLUSIONS: The optimal fixed neck position in C2-T1 PDF to reduce postoperative limitations of ADL involving neck mobility is a C2-C7 lordotic angle of less than 6°, or a C2-T1 tilt angle (°) of greater than 1.8 × the C2-C7 lordotic angle (°).

A novel posterior approach preserving three muscles inserted at C2 in multilevel cervical posterior decompression and fusion using C2 pedicle screws.

PURPOSE: To present a novel posterior approach in multilevel cervical posterior decompression and fusion (PDF) using C2 pedicle screws that preserves the rectus capitis posterior major, oblique capitis inferior, and semispinalis cervicis. METHODS: We analyzed 30 consecutive patients who underwent C2-T1 PDF using an approach that preserved these three muscles without resecting. We assessed O-C2 range of motion (ROM), cross-sectional area of the cervical posterior muscles, rotational ROM, visual analog scale (VAS) for axial pain, neck disability index (NDI), and limitations of activities of daily living (ADL) involving neck movements. RESULTS: Mean preoperative O-C2 ROM (23.6°) was significantly increased postoperatively (33.0°). Mean atrophy rate of the cross-sectional area was 3.9%. Postoperatively, 69.8% of the preoperative rotational ROM (113.3°) was retained. The preoperative VAS for axial pain and the NDI did not increase postoperatively. The postoperative O-C2 ROM (33.9°) in 26 patients for whom extension ADL were possible was significantly larger than that in four patients for whom extension ADL were impossible (26.9°). The postoperative retained rate of rotational ROM (75.8%) in 18 patients for whom rotation ADL were possible was significantly larger than that in 12 patients for whom rotation ADL were impossible (62.3%). CONCLUSIONS: This is potentially an effective approach for maintaining O-C2 ROM and rotational ROM, which enabled good levels of ADL after C2-T1 PDF. Axial pain and NDI were not worse after PDF.

K-line (-) in the Neck-Flexed Position in Patients With Ossification of the Posterior Longitudinal Ligament Is a Risk Factor for Poor Clinical Outcome After Cervical Laminoplasty.

STUDY DESIGN: Retrospective study comparing postoperative clinical outcomes after cervical laminoplasty between K-line (-) ossification of the posterior longitudinal ligament (OPLL) and K-line (+) OPLL in the neck-flexed position. OBJECTIVE: To investigate postoperative outcomes using Japanese Orthopedic Association (JOA) scores, and grip-and-release (GR) and foot-tap (FT) test scores after laminoplasty in patients with K-line (-) OPLL in the neck-flexed position. SUMMARY OF BACKGROUND DATA: Cervical laminoplasty has been reported to lead to poor outcomes in K-line (-) OPLL and good outcomes in K-line (+) OPLL. The cervical spine, however, continues moving in the extension and flexion direction after laminoplasty. METHODS: Patients with cervical myelopathy were divided into K-line (+) and (-) in the neck-flexed position. We compared postoperative outcomes after cervical laminoplasty using recovery rate, as assessed by the JOA score and degree of improvement in the six JOA score items, and performance, as assessed by GR and (FT) tests, between patients with K-line (+) OPLL (n = 18) and K-line (-) OPLL (n = 23) in the neck-flexed position. RESULTS: Recovery rate of JOA score (23.8%) of patients in the K-line (-) group was significantly lower (P = 0.028) than that (46.3%) of K-line (+) group in the neck-flexed position. In the K-line (+) group, significant improvements were seen in all JOA-score items except bladder function; however, in the K-line (-) group, improvements were seen only in upper- and the lower-extremity sensory functions. In the K-line (+) group, mean GR and FT tests significantly improved, but in the K-line (-) group, only mean FT test significantly improved. CONCLUSION: The K-line (-) OPLL in the neck-flexed position is a risk factor for poor clinical outcome after cervical laminoplasty. LEVEL OF EVIDENCE: 4.

Can MRI predict subsequent pseudarthrosis resulting from osteoporotic thoracolumbar vertebral fractures?

PURPOSE: The purpose of this study was to assess the ability of short inversion time inversion-recovery (STIR) in magnetic resonance imaging for predicting the prognosis of osteoporotic vertebral fractures. METHODS: We analyzed 63 vertebrae of 56 patients who had osteoporotic vertebral fracture (Th10-L2) prospectively. Image finding of a homogeneous high signal change on a fractured vertebra was evaluated and all vertebrae were divided into "homogenous high signal change group" or "non-homogenous high signal change group". On the other hand, image finding of linear black signal area was evaluated and all vertebrae were divided into "linear black signal area group" or "non-linear black signal area group". RESULTS: Sixteen and 24 vertebrae were included in the homogenous high signal change group or the linear black signal area group, respectively. The 16 homogenous high signal change cases did not result in non-union, and 47 non-homogenous high signal change cases resulted in 14 non-unions, a significant difference. Twenty-four linear black signal area and 39 non-linear black signal area cases resulted in 10, and 4 non-unions, respectively, also a significant difference. The kyphosis progression rate of the linear black signal area group (mean 35%) was significantly higher than that of non-linear black signal area group (mean 23%). The visual analog scale of back pain of the linear black signal area group (mean 35 mm) was significantly higher than that of the non-linear black signal area group (mean 23 mm). CONCLUSIONS: STIR was useful for predicting bone union, kyphosis, and back pain in patients with osteoporotic vertebral fracture.

Association between roentgenographic findings of the cervical spine and neck symptoms in a Japanese community population.

BACKGROUND: Radiographic findings may provide clues to the underlying cause of neck symptoms. However, these associations remain controversial. This study investigates the association between roentgenographic findings of the cervical spine and neck symptoms in a Japanese community population. METHODS: A total of 762 volunteers participated in this study. Sagittal radiographs of the cervical spine were taken and a questionnaire about the presence of and visual analog scale (VAS) for neck pain or stiff shoulder was completed. The sagittal alignment of the cervical spine (C2-C7) and the degenerative index were measured from lateral aspect radiographs. Three groups based on the sagittal alignment of C2-C7 were defined: straight-spine, lordotic-spine, and kyphotic-spine. The roentgenographic findings were examined in relation to symptoms. RESULTS: The prevalence rate of stiff shoulder on the day of examination was significantly higher in females than males. Although the VAS for neck pain and stiff shoulder on the examination day and for stiff shoulder in the preceding 12 months were not significantly different between females and males, that for neck pain in the preceding 12 months was significantly higher in females than males. Although there was no association between the sagittal alignment of C2-C7 and neck symptoms in males or females, a significant correlation between the degenerative index and VAS for neck pain on the examination day and in the preceding 12 months was seen in females after adjusting for age. The prevalence of and VAS for neck pain and stiff shoulder were not significantly different among the three C2-C7 sagittal alignment groups. CONCLUSION: Although the sagittal alignment of the cervical spine was not associated with neck symptoms, degenerative changes were associated with the severity of neck pain in females.

Novel motion preservation device for atlantoaxial instability.

STUDY DESIGN: An in vitro cadaveric biomechanical study. OBJECTIVE: To evaluate the anteroposterior (A-P) stability and the flexibility of our novel motion preservation device (MPD) using cadaveric cervical spines. SUMMARY OF BACKGROUND DATA: The MPD intended to restrict the A-P instability of the C1-C2 complex and to preserve the axial rotation, flexion, extension, and lateral bending was designed and produced. The stability and the flexibility of the MPD was evaluated. METHODS: Ten embalmed cadaveric specimens were loaded with pure A-P translation force and the A-P translational distances were measured. Each specimen was tested for the following 4 models, respectively: Intact (control), the Dens-removed, the MPD instrumented, and a Rod fixation system instrumented. Fifteen specimens were loaded with pure moments (up to 1.5 Nm), and the C1-C2 range of motion (ROM) was measured for flexion, extension, lateral bending, and axial rotation using a stereophotogrammetry motion analysis system. RESULTS: Mean A-P translational distances were 4.26 mm in Intact, 13.1 in the Dens-removed, 5.42 in the MPD, and 2.58 in the Rod fixation. The distance values with the MPD had no significant difference compared with Intact. Mean C1-C2 ROM of Intact, the MPD, and the Rod fixation at 1.5 Nm were: 14.7, 6.96, and 2.11 degrees in flexion, 6.46, 4.72, and 2.84 degrees in extension, 3.29, 4.02, and 1.01 degrees in right lateral bending, 4.92, 4.58, and 1.84 degrees in left lateral bending, 26.4, 15.4, and 1.16 degrees in right axial rotation, and 25.6, 14.3, and 1.21 degrees in left axial rotation, respectively. CONCLUSIONS: The MPD restricted the A-P instability of the C1-C2 complex. In flexion, extension, and axial rotation, the C1-C2 ROM of the MPD was about 50% of the ROM in Intact, whereas equivalent to Intact in lateral bending.

A genome-wide sib-pair linkage analysis of ossification of the posterior longitudinal ligament of the spine.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common musculoskeletal disease among people after middle age. The OPLL presents with serious neurological abnormalities due to compression of the spinal cord and nerve roots. The OPLL is caused by genetic and environment factors; however, its etiology and pathogenesis still remain to be elucidated. To determine the susceptibility loci for OPLL, we performed a genome-wide linkage study using 214 affected sib-pairs of Japanese. In stratification analyses for definite cervical OPLL, we found loci with suggestive linkage on 1p21, 2p22-2p24, 7q22, 16q24 and 20p12. Fine mapping using additional markers detected the highest non-parametric linkage score (3.43, P = 0.00027) at D20S894 on chromosome 20p12 in a subgroup that had no complication of diabetes mellitus. Our result would shed a new light on genetic aspects of OPLL.

Interobserver and intraobserver reliability of the classification and diagnosis for ossification of the posterior longitudinal ligament of the cervical spine.

PURPOSE: Ossification of the posterior longitudinal ligament (OPLL) of the cervical spine has been classified into four types by lateral plain radiographs, but the reliability of the classification and of the diagnosis of either cervical OPLL or cervical spondylotic myelopathy (CSM) was unknown. We investigated the interobserver and intraobserver reliability of the classification and diagnosis for OPLL by radiographs and computed tomography (CT) images. METHODS: A total of 16 observers classified each patient's images into five groups; OPLL continuous, segmental, mixed, circumscribed type, or CSM. To evaluate interobserver reliability, the observers first classified only radiograph images, and next both radiographs and CT images. On another day they followed the same procedure to evaluate intraobserver reliability. We also evaluated interobserver and intraobserver reliability of the diagnosis of either cervical OPLL or CSM. RESULTS: Interobserver reliability of the classification with radiographs only showed moderate agreement, but interobserver reliability with both radiographs and CT images showed substantial agreement. Intraobserver of reliability the classification was also improved by additional CT images. Interobserver reliability of the diagnosis with both radiographs and CT images was almost similar to with radiographs only. Intraobserver reliability of the diagnosis was improved by additional CT images. CONCLUSIONS: This study suggested that the reliability of the classification and diagnosis for cervical OPLL was improved by additional CT images. We propose that diagnostic criteria for OPLL include both radiographs and CT images.

The relationship between the anatomy of the nuchal ligament and postoperative axial pain after cervical laminoplasty: cadaver and clinical study.

STUDY DESIGN: A cadaver and clinical study investigated the attachment of the nuchal ligament to the cervical spinous process. OBJECTIVE: To investigate the anatomical details of the attachment of the nuchal ligament to the spinous process and the relationship between the morphology of the nuchal ligament and postoperative axial pain after laminoplasty. SUMMARY OF BACKGROUND DATA: The relationship between the length of the C6 spinous process and the morphology of the nuchal ligament and occurrence of postoperative axial pain has not been elucidated. METHODS: The morphology of the nuchal ligament was investigated in 35 cadavers and 60 patients on preoperative computed tomography and magnetic resonance imaging. The lengths of the C6 and C7 spinous processes were measured, and the C6:C7 ratio (C6 spinous process length/C7 spinous process length) was calculated. The relationship between the morphology of the attachment of nuchal ligament to the C6 spinous process and the C6:C7 ratio were investigated. In addition, the effects of the anatomy of the nuchal ligament around the C6 spinous process and different procedures of surgical invasion to C6 or C7 on postoperative axial pain were investigated for 113 patients who underwent laminoplasty. RESULTS: The nuchal ligament was attached to not only the C7 spinous process, but also the C6 spinous process when the C6:C7 ratio was more than 0.8. When the nuchal ligament was attached to the C6 spinous process and to C7, postoperative axial pain after C3-C7 laminoplasty occurred more often compared with C3-C6 laminoplasty for patients without the nuchal ligament attached to the C6 spinous process. CONCLUSION: This study shows that there is an association between the individual anatomical differences of the nuchal ligament and the occurrence of postoperative axial pain after laminoplasty. Careful attention should be paid to the morphology of the attachment of the nuchal ligament to the C6 spinous process to reduce postoperative axial pain.

Mesenchymal stem cell isolation and characterization from human spinal ligaments.

Mesenchymal stem cells (MSCs) have a fibroblast-like morphology, multilineage potential, long-term viability and capacity for self-renewal. While several articles describe isolating MSCs from various human tissues, there are no reports of isolating MSCs from human spinal ligaments, and their localization in situ. If MSCs are found in human spinal ligaments, they could be used to investigate hypertrophy or ossification of spinal ligaments. To isolate and characterize MSCs from human spinal ligaments, spinal ligaments were harvested aseptically from eight patients during surgery for lumbar spinal canal stenosis and ossification of the posterior longitudinal ligament. After collagenase digestion, nucleated cells were seeded at an appropriate density to avoid colony-to-colony contact. Cells were cultured in osteogenic, adipogenic or chondrogenic media to evaluate their multilineage differentiation potential. Immunophenotypic analysis of cell surface markers was performed by flow cytometry. Spinal ligaments were processed for immunostaining using MSC-related antibodies. Cells from human spinal ligaments could be extensively expanded with limited senescence. They were able to differentiate into osteogenic, adipogenic or chondrogenic cells. Flow cytometry revealed that their phenotypic characteristics met the minimum criteria of MSCs. Immunohistochemistry revealed the localization of CD90-positive cells in the collagenous matrix of the ligament, and in adjacent small blood vessels. We isolated and expanded MSCs from human spinal ligaments and demonstrated localization of MSCs in spinal ligaments. These cells may play an indispensable role in elucidating the pathogenesis of numerous spinal diseases.

Simple foot tapping test as a quantitative objective assessment of cervical myelopathy.

STUDY DESIGN: A clinical and cohort study. OBJECTIVE: The first purpose of this study was to investigate the standard value of a simple foot tapping test (FTT) in a large healthy population. The second purpose was to elucidate the validity of FTT as a quantitative assessment of lower extremity motor function for cervical compressive myelopathy. SUMMARY OF BACKGROUND DATA: Several clinical performance tests have been reported as objective assessments for the severity of cervical myelopathy. The FTT is the simplest and easiest method for a quantitative analysis of lower limb motor dysfunction in the upper motor neuron diseases. However, there were few studies about the FTT in cervical myelopathy. METHODS: We recruited 252 patients who were diagnosed with cervical myelopathy and 792 healthy volunteers who participated in a health promotion project. Among the patients, 126 who underwent surgery were evaluated both before and 1 year after surgery. We performed the FTT and grip and release test and evaluated the modified Japanese Orthopaedic Association (JOA) score for cervical myelopathy. RESULTS: The mean value of FTT was 23.8 ± 7.2 in myelopathic patients, which was significantly lower than 31.7 ± 6.4 in healthy controls and decreased with age. The value of FTT significantly correlated with the lower extremity motor function of modified JOA score and the value of grip and release test. Among the patients who underwent surgery, the average value of FTT was 22.4 ± 7.0 preoperatively and improved to 28.4 ± 8.1 at 1 year postoperatively. Postoperative gain of FTT significantly correlated with the gain of JOA score. CONCLUSION: The FTT results correlated with those of other tests for cervical myelopathy, and the FTT scores were improved by surgery. The FTT is an easy and useful quantitative assessment method for lower extremity motor function in patients with cervical myelopathy, especially those who cannot walk.

Genetic differences in the osteogenic differentiation potency according to the classification of ossification of the posterior longitudinal ligament of the cervical spine.

STUDY DESIGN: We categorized the four types of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine into two groups. We biochemically investigated the genetic differences in the osteogenic differentiation potency between the two groups. OBJECTIVE: To investigate the genetic differences in the osteogenic differentiation potency according to the OPLL classification. SUMMARY OF BACKGROUND DATA: Clinical studies on OPLL have revealed that the risk of progression of the ossification area is greatest for continuous and mixed type OPLL. However, until now, these four types of OPLL have been studied as a single condition. METHODS: We categorized the four types of OPLL into the OPLL continuous (continuous or mixed type) and OPLL segmental groups (segmental or circumscribed type). Paraspinal ligaments were aseptically obtained from OPLL patients during surgery. The fibroblast-like cells that migrated from the explants were used for experiments. The cells were placed in a 60-mm culture dishes for total ribonucleic acid preparation and 12 well microplates for alkaline phosphatase (ALP) activity staining. After cultures reached confluence, the cells were cultured in osteogenic medium. The messenger ribonucleic acid expression of bone morphogenetic protein-2 (BMP-2), osterix, tumor necrosis factor-α-stimulated gene-6, and ALP was analyzed by quantitative real time-polymerase chain reaction. Osteogenic differentiation of fibroblast-like cells was determined by histochemically detecting ALP production. RESULTS: After osteogenic induction, BMP-2 expression increased in the OPLL continuous and segmental groups. Osterix expression increased in the OPLL continuous group only. Tumor necrosis factor-α-stimulated gene-6 expression was suppressed in the OPLL continuous and segmental groups. ALP expression as well as ALP activity staining was higher in the OPLL continuous group than in the OPLL segmental group. CONCLUSION.: The study revealed genetic differences in the osteogenic differentiation potency between the OPLL continuous and segmental groups. We propose to distinguish OPLL continuous group from segmental group in biochemical studies on OPLL.

Perioperative cardiopulmonary complications after cervical spine surgery in the prone position: the relationship between age and preoperative testing.

BACKGROUND: Cardiac arrest during spine surgery in the prone position is difficult to manage as poor access makes cardiopulmonary resuscitation and defibrillation difficult. Advanced age is the maximal risk factor for cardiac arrest. Therefore, we wanted to determine the relationship between age and cardiac risk factors/pre-operating tests for cervical spine surgery in the prone position. METHODS: The inclusion criteria for this study specified 88 patients scheduled should undergo cervical spine surgery in the prone position. The patients were divided into two groups: Paients in group A (50 patients) were aged 69 and under, Group B (38 patients) 70 and above. All patients responded to a medical interview about eight cardiac risk factors including past history, chest symptoms, diabetes mellitus, hypertension, hyperlipidemia, obesity, smoking, and family history. All patients underwent physical examination and 24-h Holter ECG and echocardiography performed by two cardiologists before surgery. We analyzed relationships between cardiac risk factors and ECG/echocardiography and investigated intra- and postoperative cardiovascular complications. RESULTS: Although there were no significant differences in the number of cardiac risk factors between the two groups, the frequency of hypertension was significantly greater in Group B than in Group A. The frequency of abnormal ECG and echocardiography findings especially was significantly greater in Group B than in Group A. In ECG and echocardiography, three patients in Group B who had no cardiac risk factors before surgery showed abnormal findings, and one of the three patients had the amalgamation of arrhythmia after the operation. Also, in Group B, cardiovascular complications occurred in one case during operation. CONCLUSION: These results suggested that patients aged 70 and above should undergo ECG and echocardiography examination before cervical spine surgery in the prone position whether they have cardiac risk factors or not . A prospective, randomized multi-center study with a larger patient sample is warranted to ultimately demonstrate how patients should be tested before spine surgery in the prone position.

Surgical outcomes of foramen magnum decompression for syringomyelia associated with Chiari I malformation: relation between the location of the syrinx and body pain.

BACKGROUND: There have been few reports about the relation between the morphology of syrinxes and body pain in syringomyelia associated with Chiari I malformation. To investigate this phenomenon, the relation between the location of the syrinx and body pain before and after foramen magnum decompression (FMD) were evaluated. METHODS: The subjects were 20 patients with Chiari I malformation associated with syringomyelia who underwent FMD. The morphology of the syrinxes was classified into three types - enlarged type, which was a distended syrinx at the central spinal cord; deviated type, which was a deviated syrinx posterolaterally within the spinal cord; central type, which was a small syrinx at the central canal of the spinal cord - based on axial magnetic resonance imaging (MRI). Preoperative and postoperative clinical symptoms and the body pain were evaluated by the Japanese Orthopaedic Association (JOA) score and a visual analogue scale (VAS) prospectively. RESULTS: Preoperative and postoperative JOA scores showed no statistically significant differences between the three syrinx types. Intensity of body pain evaluated by the VAS showed that patients with a deviated-type syrinx on pre- and postoperative MRI tended to be associated with more intense pain than the other two types. CONCLUSIONS: It was indicated that pain before and after surgery is more intense when the syrinx is deviated toward the spinal dorsal horn as seen on MRI.

Comparison of cardiovascular parameters between patients with ossification of posterior longitudinal ligament and patients with cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA: Ossification of the posterior longitudinal ligament (OPLL) is an ectopic bone formation in the ligament tissue of the spine, causing myelopathy as a result of chronic pressure on the spinal cord and nerve roots. It has been further categorized into 4 types, that is, segmental, continuous, mixed types, and the other types; however, differences in the detail of the progression in the ossification and natural history of the disease among these types have not been clarified. OBJECTIVE: To find out the systemic feature, which has relevance to the disease state of OPLL. METHODS: To characterize these types, we conducted an investigation of cardiovascular factors [blood pressure, blood loss during or after surgery, bleeding time, coagulation factors (prothrombin test, activated partial thromboplastin time)] among OPLL, cervical spondylotic myelopathy (CSM), and subtypes of OPLL (continuous, mixed, segmental, and the other types). STUDY DESIGN: Retrospective case series. RESULTS: These parameters of patients with cervical spondylotic myelopathy were used as a control (CSM patients). Although there was no significant difference in bleeding time and coagulation factors, blood loss after surgery of OPLL patients was significantly higher than that of CSM patients (P<0.01). Furthermore, blood loss of patients with continuous type of ossification was significantly higher (P<0.05) than that of patients with segmental type of ossification, which was nearly equal to that of CSM patients. Blood loss of patients with mixed type of ossification showed the value of the middle of segmental and continuous types.

Spinal cord shift on magnetic resonance imaging at 24 hours after cervical laminoplasty.

STUDY DESIGN: A prospective study in 19 patients after cervical laminoplasty, using magnetic resonance imaging. OBJECTIVE: To evaluate the value of spinal cord shift at 24 hours after cervical laminoplasty. SUMMARY OF BACKGROUND DATA: Postoperative C5 palsy is a noticeable complication within 1 week after cervical laminoplasty. The root tethering due to the posterior shift of the spinal cord after laminoplasty was reported as one of the causes of C5 palsy. However, the spinal cord shift after surgery within 1 week is unknown. METHODS: The posterior shift of the spinal cord was measured in 19 consecutive patients on magnetic resonance images at 24 hours and 2 weeks after cervical laminoplasty. RESULTS: The mean posterior shift of the spinal cord at 24 hours was 2.8 mm, with the maximum at the C5 level, decreasing to 1.9 mm at 2 weeks. The posterior shift of the spinal cord at C5 was correlated with the amount of the dura mater at C4, C5, and C6 levels. In a patient with right C5 palsy, posterior shift at C5 level was 5.5 mm, decreasing to 3.0 mm at 2 weeks after surgery. The posterior shift of the spinal cord was not correlated with the sagittal alignment. CONCLUSION: The posterior shift of the spinal cord at 24 hours had a tendency to shift more posteriorly than that observed at 2 weeks after cervical laminoplasty. C5 palsy may be prevented if the expansion of dura mater, which is strongly correlated with the posterior shift, can be controlled.

Surgical anatomy of the nuchal muscles in the posterior cervicothoracic junction: significance of the preservation of the C7 spinous process in cervical laminoplasty.

STUDY DESIGN: An anatomic study investigated the attachment of the nuchal muscles to the spinous process. OBJECTIVE: To investigate the anatomic details of the attachment of the nuchal muscles to the spinous process, and which muscles are spared, and to what extent, when the C7 spinous process is preserved in the cervical laminoplasty. SUMMARY OF BACKGROUND DATA: In previous studies, it was reported that the incidence of postoperative axial pain was lower in C3-C6 laminoplasty than in C3-C7 laminoplasty, emphasizing the effectiveness of the former procedure where discission of the nuchal muscles that are attached to the C7 spinous process is avoided. However, there have been no detailed anatomic studies of the attachment of the nuchal muscles to the spinous process at the cervicothoracic junction. METHODS: The anatomy of the speculum rhomboideum of the trapezius, rhomboideus minor, rhomboideus major, serratus posterior superior, splenius capitis, and splenius cervicis to the spinous processes of the cervicothoracic junction were studied using 50 cadavers. RESULTS: The possibility of total discission of the speculum rhomboideum of the trapezius was 0% with C3-C6 laminoplasty and 18% with C3-C7 laminoplasty. More than 50% preservation of the speculum rhomboideum of the trapezius is possible in 72% in C3-C6 laminoplasty and 16% in C3-C7 laminoplasty. In C3-C7 laminoplasty, the possibility of partial preservation of the rhomboideus minor, serratus posterior superior, and splenius capitis at the spinous process was 0%, 66%, and 29%, respectively. The rhomboideus major in 16% and the splenius cervicis in 56% could be completely preserved without partial discission of the muscle attachment. On the other hand, in C3-C6 laminoplasty, the muscles that were spared without complete discission of the muscular attachment at the spinous process were the rhomboideus minor in 35%, the serratus posterior superior in 100% and the splenius capitis in 67%. The rhomboideus major in 76% and the splenius cervicis in 80% were completely spared without partial discission of the muscular attachment. CONCLUSION: The current study confirmed that C3-C6 laminoplasty in which the C7 spinous process is preserved reduces invasion of the nuchal muscles.