Reliability of Conventional Two-Dimensional Magnetic Resonance Imaging for Diagnosing Extraforaminal Stenosis in Lumbosacral Transition.

Introduction: Three-dimensional (3D) magnetic resonance imaging (MRI) is reportedly superior to two-dimensional (2D) MRI for diagnosing lumbar foraminal stenosis at L5-S1. In this study, we strictly distinguished the intra- and extraforaminal regions and compared the diagnostic reliability and accuracy of 2D and 3D MRI in each region. Methods: A total of 92 surgical cases of unilateral L5 radiculopathy were selected for imaging analysis, including 46 of foraminal stenosis at L5-S1 (Group F) and 46 of intraspinal canal stenosis at L4-5 (Group C) (48 men, 44 women; mean age, 66 years). The 2D and 3D MRI sets were assessed twice by two examiners. They were informed only of the laterality of the lesion in each case and asked to select among the following for each modality: "absence of foraminal stenosis," "intraforaminal stenosis," "extraforaminal stenosis," and "coincident intraforaminal and extraforaminal stenosis." The intra- and interobserver reliabilities were evaluated using kappa (κ) statistics for the intra- and extraforaminal regions and compared between 2D and 3D MRI. For each case, disagreements between examiners were resolved through discussion to obtain a diagnostic judgment for each modality. Subsequently, the final diagnosis of intra- and/or extraforaminal stenosis in Group F was made using multiple modalities and intraoperative findings. A comparison between 2D and 3D MRI in terms of diagnostic accuracy was performed for the intra- and extraforaminal regions. Results: No significant difference was observed in the κ statistics between 2D and 3D MRI for the intraforaminal region, whereas 3D MRI had significantly larger κ statistic than 2D MRI for the extraforaminal region. Ultimately, 3D MRI perfectly judged the extraforaminal region, whereas 2D MRI detected only 44.8% of the cases of extraforaminal stenosis. Conclusions: More than half of extraforaminal stenosis was overlooked by 2D MRI, suggesting that it is unreliable for diagnosing extraforaminal stenosis at L5-S1.

Are T1-Weighted Three-Dimensional Magnetic Resonance Images Inferior to T2-Weighted Images for Diagnosing Lumbar Foraminal Stenosis in the Fifth Lumbar Nerve Root? A Prospective, Comparative Study in Identical Patients.

Introduction: Imaging analysis of foraminal stenosis in the fifth lumbar (L5) nerve root remains to be a challenge because of the anatomical complexity of the lumbosacral transition. T2-weighted three-dimensional (3D) magnetic resonance images (MRI) have been dominantly used for diagnosis of lumbar foraminal stenosis, while the reliability of T1-weighted images (WI) has also been proven. In this study, we aim to compare the reliability and reproducibility of T1- and T2-weighted 3D MRI in diagnosing lumbar foraminal stenosis (LFS) of the L5 nerve root. Methods: In this study, 39 patients with unilateral L5 radiculopathy (20 had L4-L5 intracanal stenosis; 19 had L5-S foraminal stenosis) were enrolled, prospectively. T1- and T2-weighted 3D lumbar MRI were obtained from each patient. T1WI and T2WI were blinded and then separately reviewed twice by four examiners randomly. The examiners were instructed to answer the side of LFS or absence of LFS. The correct answer rate, sensitivity, specificity, and area under the curve were analyzed and compared between T1WI and T2WI. Also, intra- and interobserver agreements were calculated using kappa (κ)-statistics and compared in the same manner. Results: The average correct answer rate, sensitivity, specificity, and area under the curve of the T1WI/T2WI were 84.6%/80.1%, 82.9%/80.3%, 86.3%/81.3%, and 0.846/0.801, respectively. The intraobserver κ-values of the four examiners ranged from 0.692 to 0.916 (average: 0.762) and from 0.669 to 0.801 (average: 0.720) for T1WI and T2WI, respectively. The interobserver κ-values calculated in a round-robin manner (24 combinations in total) ranged from 0.544 to 0.790 (average: 0.657) and from 0.524 to 0.828 (average: 0.652), respectively. Conclusions: As per our findings, T1- and T2-weighted 3D MRI were determined to have nearly equivalent reliability and reproducibility in terms of diagnosing LFS of the L5 nerve root.

Radical decompression without fusion for L5 radiculopathy due to foraminal stenosis.

Background: The highest incidence of lumbar foraminal stenosis (LFS) occurs in the L5-S1 segment and its anatomical features differ from those of other segments. Few previous reports have exhaustively assessed surgical outcomes after decompression surgery, limiting the materials to patients with LFS at the L5-S1 segment. We aimed to prospectively investigate instability and neurological improvement following our novel surgical technique for LFS at L5-S1, named "radical decompression" of the nerve root. Methods: Patients with foraminal stenosis at L5-S1 who underwent surgery using our technique were prospectively evaluated two years postoperatively. The Japanese Orthopaedic Association (JOA) score and the JOA Back Pain Evaluation Questionnaire (JOABPEQ) were evaluated preoperatively and two years postoperatively. The following radiological parameters at L5-S1 were measured: lateral translation, sagittal translation, the difference in sagittal translation (DST) between flexion and extension, disc wedging angle, lordotic angle, the difference in lordotic angle (DLA) between flexion and extension, and disc height. Pre- and postoperative data were compared using paired t-tests. In addition, the patients were classified into a disc group (Group D) and a non-disc group (Group ND) according to whether a discectomy was performed intraoperatively. Changes in each parameter before and after surgery were compared between the groups. Results: Twenty-eight patients were included in this analysis. The JOA scores improved in all patients. The mean preoperative and two-year postoperative JOA scores were 14.5±3.2 (range, 8-21) and 24.3±3.3 (range, 18-29), respectively (P<0.01). All JOABPEQ categories improved two years postoperatively (P<0.05). None of the patients underwent revision surgery. No significant changes were observed in any of the radiological parameters. No significant differences in the changes in each parameter before and after surgery were found between groups D and ND. Conclusions: Our surgical technique resulted in good neurological recovery and was associated with a low risk of postoperative segmental instability, regardless of additional discectomy.

Quercetin improves lacrimal gland function through its anti-oxidant actions: Evidence from animal studies, and a pilot study in healthy human volunteers.

Anti-oxidant properties of polyphenols have been gaining medical attention as a preventive factor against aging and/or lifestyle diseases. In this study, we examined the anti-oxidant activity of quercetin improved tear function through its effects on the lacrimal gland in mice and humans. Six week-old diabetic mice, a model for decreased tear production, were fed for 12 weeks ad libitum with an experimental diet containing 0.5% quercetin. As a result, the tear volume was significantly improved compared to the control, despite no changes in body weight, food intake, lacrimal gland morphology or biochemical serum parameters. Moreover, significantly higher SOD-1 and SOD-2 protein levels were detected in the lacrimal glands of quercetin-treated mice by western blot. In addition, quercetin treatment of mouse corneal cell lines exposed to oxidative stress resulted in dose-dependent inhibition of ROS production and enhanced cell survival. Finally, we examined quercetin pharmacokinetics, specifically its presence in serum and tears subsequent to onion consumption in healthy volunteers, and found that the distribution of quercetin and its metabolite shifted from serum to tear following onion intake. An improvement in tear film stability also resulted following the intake by these healthy volunteers of a new, quercetin-rich onion cultivar ("Quergold") in powder form. These results suggested that quercetin improved tear function through its effects on the lacrimal gland in mice and humans.

Electrolyzed hydrogen-rich water for oxidative stress suppression and improvement of insulin resistance: a multicenter prospective double-blind randomized control trial.

INTRODUCTION: Electrolyzed hydrogen-rich water (EHW) is known to have suppressive effects on oxidative stress (OS). However, its benefit in type 2 diabetes mellitus (T2DM) remains unclear. This study aimed to investigate the effect of EHW on T2DM. METHODS: This was a multicenter, prospective, double-blind, randomized controlled trial of 50 patients with T2DM who were assigned to the EHW or filtered water (FW) groups. The primary endpoint was changes in insulin resistance (IR) evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR). OS markers such as urinary 8-hydroxy-2'-deoxyguanosine excretion (8-OHdG), plasma diacron-reactive oxygen metabolites (d-ROM), and plasma biological antioxidant potential (BAP) and other clinical data, including serum lactate concentration (lactate), were evaluated. RESULTS: There were no significant differences in the changes in HOMA-IR between the EHW and FW groups. However, lactate levels decreased significantly in the EHW group, and this decrease was significantly correlated with a reduction in HOMA-IR, fasting plasma glucose, and fasting plasma insulin level. Serum lactate level also significantly correlated to decreased insulin bolus secretion after 90 min with glucose loading in the EHW subjects with HOMA-IR > 1.73. No EHW treatment-related adverse effects were observed. CONCLUSION: There were no significant effect of EHW in the change in HOMA-IR in this study; larger-scale and longer-term study are needed to verify the effects of EHW in T2DM patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13340-021-00524-3.

Foraminal Stenosis at L5-S1 as an Overlooked Pathology of Bilateral Radiculopathy: A Case Series.

Introduction: The classical symptom of foraminal stenosis is unilateral radiculopathy. Bilateral radiculopathy caused purely by foraminal stenosis is rare. Here, we report five cases of bilateral L5 radiculopathy caused purely by L5-S1 foraminal stenosis and describe the clinical and radiological features of these patients in detail. Case Presentation: Among the five patients, two were men and three were women with an average age of 69 years. Four patients had undergone surgeries at L4-5 level, previously. All the patients showed an improvement in symptoms in the post-operative period. After a certain period, the patients complained of bilateral leg pain and numbness. An additional surgery was performed in two patients; however, there was no improvement in symptoms. One patient, who did not undergo surgery, was treated conservatively for 3 years. All the patients had been suffering from bilateral leg symptoms before their first visit to our hospital. The neurological findings in these patients were consistent with bilateral L5 radiculopathy. The average pre-operative Japanese Orthopedic Association (JOA) score was 13 out of 29 points. Bilateral foraminal stenosis at L5-S1 level was confirmed using a three-dimensional magnetic resonance imaging or computed tomography. Posterior lumbar interbody fusion was performed in one patient and bilateral lateral fenestration using Wiltse's approach was performed in four patients. The neurological symptoms recovered immediately after surgery. The average JOA score at 2-year follow-up was 25 points. Conclusions: Spine surgeons may overlook the pathology of foraminal stenosis, particularly in patients with bilateral radiculopathy. Familiarity with the clinical and radiological features of symptomatic lumbar foraminal stenosis is necessary to properly diagnose bilateral foraminal stenosis at L5-S1 level.

Imaging diagnosis of lumbar foraminal stenosis in the fifth lumbar nerve root: reliability and reproducibility of T1-weighted three-dimensional lumbar MRI.

BACKGROUND: Various magnetic resonance imaging (MRI) techniques have been reported in detection of lumbar foraminal stenosis (LFS), especially for T2-weighted three-dimensional MRI (3D-MRI) describing the shape of nerve roots. The detection of LFS in the fifth lumbar nerve root (L5 root), however, is still less reliable compared to other lumbar nerve roots. Then we have been using T1-weighted 3D-MRI aiming to depict the shape of, and also pathology affecting the L5 root. The aim of this study is to evaluate our T1-weighted 3D-MRI in diagnosing LFS of the L5 root. METHODS: This retrospective study included 24 patients with intracanal stenosis (ICS) at L4-5, and 30 patients with LFS at L5-S causing unilateral L5 root lesion. The pre-operative T1-weighted 3D-MRI aiming bilateral L5 nerve roots of each patient were blinded and reviewed twice by five spine surgeons, independently. The image evaluation was performed in two conditions: (I) the symptomatic side was judged in 30 patients of LFS patients, and (II) the symptomatic side or the absence of LFS was judged in images of all the 54 patients including LFS and ICS patients. The correct-answer-rate, sensitivity and specificity of the imaging study were calculated. Also, the intra- and interobserver agreement of the imaging study by five spine surgeons were evaluated by the kappa (κ) statistics. RESULTS: For conditions (I) and (II) above, the mean correct-answer-rate was 92.3% and 69.8%, respectively. The sensitivity and specificity of the imaging study was 72.6% and 66.3%, respectively. The average of intraobserver κ-value of five examiners was 0.874 and 0.708, and the average of interobserver κ-value was 0.837 and 0.578, respectively. CONCLUSIONS: As well as previously reported T2-weighted 3D-MRI, our T1-weighted 3D-MRI was found to be reliable in diagnosing LFS of the L5 root.

Anterior Decompression and Fusion Versus Laminoplasty for Cervical Myelopathy Caused by Soft Disk Herniation: A Long-term Prospective Multicenter Study.

STUDY DESIGN: A prospective multicenter study. OBJECTIVE: The purpose of this study was to determine whether laminoplasty (LP) is comparable for myelopathy caused by cervical disk herniation (CDH). SUMMARY OF BACKGROUND DATA: Anterior decompression and fusion (ADF) has conventionally been used for myelopathy caused by CDH with stable outcomes. However, recurrence of myelopathy due to adjacent segment degeneration are its drawbacks. The efficacy of LP without discectomy has been sporadically reported, but no long-term prospective study has been conducted to verify it. MATERIALS AND METHODS: Patients with cervical myelopathy caused by CDH were studied. The first 30 patients and the next 30 patients were treated with ADF and LP, respectively. The outcomes were compared between the 22 ADF patients and the 20 LP patients who had completed the follow-up examination scheduled 10 years after surgery. RESULTS: There was no statistically significant difference in the postoperative severity or recovery rate of myelopathy between the 2 groups 10 years after surgery. One patient in the ADF group underwent LP for secondary myelopathy due to adjacent segment degeneration 2 years after the surgery. Reoperation was not required for patients in the LP group. Postoperative neck pain was significantly more severe in the LP group than in the ADF group. CONCLUSIONS: ADF and LP for cervical myelopathy caused by CDH achieve similarly favorable outcomes. Recurrence of myelopathy caused by adjacent segment degeneration is a disadvantage of ADF while residual neck pain is a disadvantage of LP.

Rate of spinal surgery in a rapidly aging society: the 27-year changes in Miyagi prefecture, Japan.

BACKGROUND: Japan has had a rapidly aging population during the past 30 years. This study aimed to investigate longitudinal changes in the surgical rate for spinal disorders in Miyagi Prefecture (2.35 million inhabitants) with a similar population composition to Japan. METHODS: Data of spinal surgeries were collected using the spine registry by Tohoku University Spine Society. Data on the annual number of spinal surgeries between 1988 and 2014 of all populations, in those aged ≥65 years old, in those aged ≥75 years old, and for each pathology were collected. The annual surgical rate per 100,000 inhabitants was calculated. RESULTS: The surgical rate in 2010-2014 in total, at ≥65 years old, and at ≥75 years old showed 3.2-, 3.8- and 7.1-fold increases, respectively, compared with that in 1988-1989. Degenerative spinal disorders, spinal trauma and pyogenic spondylitis markedly increased, while metastatic spinal tumor and tuberculous spondylitis decreased over time. The surgical rate at ≥75 years with lumbar spinal stenosis showed a 12.6-time increase. CONCLUSIONS: During a rapid period of aging, the rate of spinal surgeries has markedly increased, particularly, that for degenerative disorders. This is the first report on the long-term longitudinal changes in the rate of spinal surgery.

Reoperation Rates after Laminoplasty for Cervical Disorders: A 26-Year Period Survival Function Method Analysis.

INTRODUCTION: Laminoplasty is a common surgery for cervical myelopathy. Previous studies have analyzed the reoperation rates in posterior decompression surgeries of the cervical spine. However, few studies have solely focused on midline-splitting laminoplasty (MSL) using a large number of patients. This aims to analyze the reoperation rates after MSL using the survival function method. METHODS: Between 1988 and 2013, 4,208 MSLs were performed as a primary operation for cervical myelopathy and enrolled in our spinal surgery registration system. The Kaplan-Meier survival function method was used to analyze the rates of reoperation. RESULTS: Of 4,208 patients with primary MSL, 40 underwent reoperation for neurological complications. The overall reoperation rate was 0.26%, 0.64%, 0.83%, 0.93%, and 0.95% at 1, 5, 10, 20, and >20 years, respectively. The causes of reoperation were postoperative cervical radiculopathy in 10 patients, stenosis at an adjacent level in 8, stenosis due to failed "open-door" lamina in 6, instability of the cervical spine in 4, cervical disc herniation in 3, elongation of ossification of the posterior longitudinal ligament in 3, spinal cord injury in 1, fracture of the cervical spine in 1, postoperative scar formation in 1, ossification of anterior longitudinal ligament in 1, and unknown in 2. The number of patients with surgical site infection (SSI) who needed surgical debridement was 34 (0.81%). CONCLUSIONS: Excluding reoperations for SSI, the reoperation rate of MSL was approximately 1.0% at the maximum of 26 years after surgery. MSL was determined to be a reliable surgical procedure regarding postoperative complications requiring additional surgeries.

Ocular-Component-Specific miRNA Expression in a Murine Model of Lens-Induced Myopia.

To identify tissues and molecules involved in refractive myopic shift and axial length elongation in a murine lens-induced myopia model, we performed a comprehensive analysis of microRNA (miRNA) expression. Three weeks after negative 30 diopter lens fixation on three-week-old C57BL/6J mice, total RNA was extracted from individual ocular components including cornea, iris, lens, retina, retinal pigment epithelium (RPE)/choroid, and sclera tissue. The miRNA expression analysis was pooled from three samples and carried out using Agilent Mouse miRNA Microarray (8 × 60 K) miRBase21.0. The expression ratio was calculated, and differentially expressed miRNAs were extracted, using GeneSpring GX 14.5. Myopic induction showed a significant myopic refractive change, axial elongation, and choroidal thinning. Through the comprehensive miRNA analysis, several upregulated miRNAs (56 in cornea tissue, 13 in iris tissue, 6 in lens tissue, 0 in retina tissue, 29 in RPE/choroid tissue, and 30 in sclera tissue) and downregulated miRNAs (7 in cornea tissue, 28 in iris tissue, 17 in lens tissue, 9 in retina tissue, 7 in RPE/choroid tissue, and 40 in sclera tissue) were observed. Overlapping expression changes in miRNAs were also found in different ocular components. Some of this miRNA dysregulation may be functionally involved in refractive myopia shift and axial length elongation.

Compensatory increases in tear volume and mucin levels associated with meibomian gland dysfunction caused by stearoyl-CoA desaturase-1 deficiency.

The stearoyl-CoA desaturase (SCD) family of enzymes catalyzes monounsaturated fatty acid synthesis by inserting a cis double bond at the Δ9 position of saturated fatty acids. Disruption of these enzymes has been reported to induce a severe dry skin phenotype. Since lipid abnormalities in the meibomian glands have been associated with dry eye, we analyzed selected eye tissues contributing to tear volume and composition in genetically SCD-1-deficient mice (SCD-1 KO), including the lacrimal glands and conjunctiva. Previous histopathological analysis had revealed atrophy and loss of meibomian glands; taken together with the increased goblet cell and MUC5AC expression in the conjunctiva reported here, these findings suggest that the tear volume and mucin levels secreted are enhanced in the absence of lipid secretion as a compensatory mechanism. The expression of lipid metabolism genes in lacrimal glands was decreased in SCD1 KO mice. Thus, these results provide new pathophysiological mechanisms to pursue with regard to meibomian gland dysfunction. In addition, lack of SCD-1 causes a compensatory increase in the tear volume and mucin levels associated with changes in expression of lipid metabolism genes. These results may be useful as a new concept for dry eye treatment strategies.

Lumbosacral Transitional Vertebrae Cause Spinal Level Misconception in Surgeries for Degenerative Lumbar Spine Disorders.

Human lumbar spine usually consists of five vertebrae; however, some individuals have vertebral anomalies with four or six lumbar vertebrae because of sacralized fifth lumbar vertebra (L5 sacralization) or lumbarized first sacral vertebra (S1 lumbarization), respectively. These vertebral anomalies are called lumbosacral transitional vertebra (LSTV). Although LSTV is an asymptomatic anomaly, it is known to cause misconception in spinal counts and in spinal level at lumbar spinal surgery. The purpose of this study is to evaluate how LSTV affects the diagnosis and surgeries in lumbar spine disorders. In 550 consecutive patients who underwent lumbar spinal surgeries, a whole-spine X-ray was taken on admission to assess the true number of lumbar vertebrae. We assessed the coherence between the neurological level diagnosis and the level of spinal canal stenosis on imaging studies before and after the recognition of LSTV to clarify how recognition of LSTV affected pre-operative surgical planning. Out of 550 patients, LSTV was found in 71 (12.9%) patients: 37 cases with L5 sacralization and 34 cases with S1 lumbarization. The number of vertebrae was miscounted at the outpatient department (OPD) in 38 cases (54%): 10 L5-sacralization cases and 28 S1-lumbarization cases. Moreover, surgical spinal levels were altered from the original surgical plans at OPD in 11 cases (15%; 3 L5-sacralization and 8 S1-lumbarization cases), after recognizing the true spinal counts by the whole spine X-ray. To avoid errors in spinal level diagnosis, we should recognize the possibility of LSTV that could be assessed by a whole spine X-ray.

New diagnostic support tool for patients with leg symptoms caused by lumbar spinal stenosis and lumbar intervertebral disc herniation: A self-administered, self-reported history questionnaire.

BACKGROUND: There are no diagnostic support tools composed of a simple, single-sheet, self-administered, self-reported history questionnaire (SSHQ) for patients with leg symptoms caused by either lumbar spinal stenosis (LSS) or lumbar disc herniation (LDH), at the same time, can discriminate the two diseases. METHODS: We conducted retrospective and prospective derivation studies and a prospective validation study. Based on data from 137 patients with LSS and 206 with LDH, we identified key prediction factors to establish the diagnosis of LSS and LDH, which became the basis of a temporary SSHQ. Next, we performed a prospective derivation study in which 296 patients with LSS or LDH completed preoperatively this temporary SSHQ. After univariate and multivariate analyses of each question, questions on both diseases in addition to age factor were selected, providing the final version of the SSHQ. A validation study was subsequently performed with 342 consecutive patients with leg symptoms. The sensitivity, specificity and likelihood ratio of this SSHQ were calculated to determine the cut-off points for LSS and LDH. RESULTS: A SSHQ with 15 questions was developed from retrospective and prospective derivation studies. The score of each question was weighted based on the multivariate analysis and then, it was approximated to integer value. According to assessment of the discriminatory performance of the clinical prediction rule of the SSHQ, the cut-off point for LSS was ≥13 and that for LDH was ≥11. The sensitivity, specificity, and positive and negative likelihood ratios of this SSHQ at those cut-off points were, respectively, 92.7%, 84.7%, 6.07, and 0.09 for LSS, and 91.0%, 85.2%, 6.15, and 0.11 for LDH. CONCLUSIONS: This is the first report of a diagnostic support tool for patients with LSS- or LDH-induced leg symptoms combined in a single SSHQ that could help establish diagnosis of the two diseases in the daily clinical practice.

Increasing Incidence of Degenerative Spinal Diseases in Japan during 25 Years: The Registration System of Spinal Surgery in Tohoku University Spine Society.

Spinal disorders affect mainly older people and cause pain, paralysis and/or deformities of the trunk and/or extremities, which could eventually disturb locomotive functions. For ensuring safe and high-quality treatment of spinal disorders, in 1987, the Tohoku University Spine Society (TUSS) was established by orthopedic departments in Tohoku University School of Medicine and its affiliated hospitals in and around Miyagi Prefecture. All spine surgeries have been enrolled in the TUSS Spine Registry since 1988. Using the data from this registration system between 1988 and 2012, we demonstrate here the longitudinal changes in surgical trends for spinal disorders in Japan that has rushed into the most advanced "aging society" in the world. In total, data on 56,744 surgeries were retrieved. The number of spinal surgeries has annually increased approximately 4-fold. There was a particular increase among patients aged ≥ 70 years and those aged ≥ 80 years, with a 20- to 90-fold increase. Nearly 90% of the spinal operations were performed for degenerative disorders, with their number increasing approximately 5-fold from 705 to 3,448. The most common disease for surgery was lumbar spinal stenosis (LSS) (35.9%), followed by lumbar disc herniation (27.7%) and cervical myelopathy (19.8%). In 2012, approximately half of the patients with LSS and cervical myelopathy were ≥ 70 years of age. In conclusion, the number of spinal operations markedly increased during the 25-year period, particularly among older patients. As Japan has a notably aged population, the present study could provide a near-future model for countries with aging population.

Reoperation rates after fenestration for lumbar spinal canal stenosis: a 20-year period survival function method analysis.

PURPOSE: Fenestration is the gold standard surgery for lumbar spinal canal stenosis in Japan. Several previous studies have analyzed the reoperation rates in large numbers of patients undergoing several surgical procedures such as laminectomy with or without instrumented spinal fusion; however, there have been few studies focusing solely on fenestration. The purpose of this study was to calculate the reoperation rates after fenestration using the survival function method. METHODS: Form 1988-2007, 6,998 surgeries for lumbar spinal canal stenosis occurred in Miyagi prefecture, Japan, and these patients were enrolled by the spinal surgery registration system of the Department of Orthopaedic Surgery, Tohoku University. Among these, 5,835 surgeries involved fenestration as a primary surgery and for those who underwent ≥2 lumbar surgeries we analyzed the reoperation rates using the Kaplan-Meier method. RESULTS: Among the 5,835 patients undergoing primary fenestration, 215 patients underwent 221 revisions; 112 included the same spinal levels and 103 were revised only at other levels as primary fenestration. The overall reoperation rates were 0.8% at 1 year, 2.9% at 5 years, 5.2% at 10 years, 7.5% at 15 years and 8.6% at >17.7 years. Reoperation rates for those at the same spinal levels were 0.6% at 1 year, 1.7% at 5 years, 2.7% at 10 years, 3.8% at 15 years, and 4.1% at >17.0 years. CONCLUSIONS: Fenestration can be performed at low cost using standard spinal surgery equipments. The reoperation rates of this procedure were lower than previously reported for several other surgical procedures.

Elderly-onset degenerative "lumbar spondylotic myelopathy" in a patient with a low-placed spinal cord successfully treated by laminotomy: a case report.

The authors report a rare case of elderly-onset "lumbar spondylotic myelopathy" occurred on a low-placed spinal cord compressed at multiple levels with thickened ligamenta flava. A posterior decompression surgery could alleviate neurological symptoms successfully instead of untethering of the spinal cord, a widely accepted surgery for tethered cord.

Fracture and contralateral dislocation of the twin facet joints of the lower cervical spine.

PURPOSE: The combination of a facet fracture and a contralateral facet dislocation at the same intervertebral level of the cervical spine (a fracture and contralateral dislocation of the twin facet joints) has not been described in detail. The aims of this study are to report a series of 11 patients with this injury, to clarify the clinical features and to discuss its pathomechanism. METHODS: Among 251 patients with lower cervical spine fractures and/or dislocations surgically treated, 11 (9 males and 2 females, averaged age, 52 years) had this kind of injury. Medical charts and medical images were reviewed retrospectively. RESULTS: Injury levels were C4-5, C5-6 and C6-7 in 1, 4 and 6 patients, respectively. A fracture was found at the superior facet in 6, and at the inferior facet in 5. The anterior displacement of the vertebral body ranged from 7 to 19 mm. The unilateral horizontal facet appearance on an anteroposterior radiograph and the triple image on a CT composed of a separated fracture fragment, the base of the fractured facet, and the neighboring non-fractured facet were characteristic. All patients had neurological deficits from Frankel A to D, and were surgically treated by posterior fusion using wire or cable, or combined anterior and posterior spinal fusion. CONCLUSIONS: The fracture and contralateral dislocation of the twin facet joints can cause severe neurological deficits because of its gross anterior displacement. Its plausible pathomechanism is extension force exerted to the cervical spine when it is maximally bent laterally.