Estenosis lumbar degenerativa: conceptos básicos, evaluación clínica y manejo / Degenerative lumbar spinal stenosis: basic concepts, clinical evaluation, treatment

La estenorraquis lumbar es la disminución del volumen del canal raquídeo en la columna. Es la causa más frecuente de dolor lumbociático y lumbocrural en población mayor de 60 años. Existen múltiples causas. La más común es la degenerativa que consiste en una disminución del canal secundario a varios factores como protrusión del disco intervertebral, hipertrofia y abombamiento del ligamento amarillo, engrosamiento de la capsula articular y por osteofitos. Los síntomas principales son el dolor lumbar irradiado a extremidades inferiores tipo lumbociática o lumbocruralgia y la claudicación neural intermitente. Generalmente no hay déficit motor ni sensitivo. La resonancia magnética es el estudio de elección para el diagnóstico, pero debe complementarse con radiografías y con frecuencia con tac para una mejor valoración de la patología. El tratamiento inicial siempre es conservador, que incluye uso de antiinflamatorios, analgésicos, relajantes musculares, kinesioterapia e infiltraciones de columna (epidurales o radiculares). La mayoría de los pacientes responden satisfactoriamente a este manejo. El tratamiento quirúrgico está indicado a los pacientes que presentan un dolor intenso, que afecta su calidad de vida y que no mejora con el tratamiento conservador. Consiste en la descompresión quirúrgica de las raíces lumbares a través de laminectomía. En ocasiones se recomienda complementar la descompresión con artrodesis específicamente cuando la estenorraquis se asocia a otras condiciones como espondilolistesis degenerativa, escoliosis, desbalance sagital o coronal, inestabilidad segmentaria y en enfermedad del segmento adyacente.

Spinal lumbar stenosis is a narrowing of the spinal canal in the lumbar spine. Is the most frequent cause of sciatic pain or cruralgia in the elderly population over 60 years old. Exist many etiologies. The most common is degenerative caused by many factors including bulging disc, hypertrophy of flavum ligament as well as facet capsule thickening and by osteophytes formation. The main symptoms of spinal stenosis are radicular pain and neurogenic claudication. Lumbar flexion usually improves the symptom and deambulation often worsens the pain. Most of the time neurologic examination is normal. The gold standard study is mri but is necessary to complement with x rays and ct to obtain a better evaluation. Initial treatment is always conservative and consists in nsaid's, muscle relaxants, physical therapy and steroid spinal injections. Most of the patients respond well to this treatment. Surgical treatment is indicated when the patient has a severe pain, quality of life is miserable and conservative treatment fails. Decompression is the gold standard surgical treatment. The addition of an arthrodesis or spinal fusion is recommended in degenerative spondylolisthesis, scoliosis, sagital or coronal imbalance, deformity correction, recurrent spinal stenosis and in cases of adjacent level disease problem.

Influence of age, sex, height and lumber stenosis on the position of the conus medullaris in adults / Influencia de la edad, sexo, altura y estenosis lumbar en la posición del cono medular en adultos

Anatomical orientation of the termination level of Conus Medullaris (CM) has imperative role clinically for anesthetists and neurosurgeons which is considered as an objective guide to perform spinal anesthesia and spinal punctures circumspectly with less chance to have serious injuries. The current retrospective study was carried on to determine the location of the CM and how its termination level can be influenced by age, sex, height and lumber stenosis spine disease. The study included 462 participants that consisted of 199 men and 263 women range from 21 to 80 years of age and height range between 150-190 cm. Also, it included 150 lumber stenosis patients. The location of the CM was imaged using a series of magnetic resonance images (MRI) for the lumbosacral spine at different levels including, T12, T12-L1, L1, L1-L2, and L2. The measurements revealed inconsiderable differences in the CM termination level in relation to age, sex and height in a healthy study population. Moreover, the results showed insignificant differences in the CM termination level between men and women whether they are healthy or having lumbar spinal stenosis. In conclusion, the most common level of CM termination is at L1 followed by L1-L2. It is safe to perform a lumbar neuraxial procedures at the level of L3-L4.

La orientación anatómica del nivel de terminación del Conus medullaris (CM) tiene un importante papel clínico para los anestesistas y neurocirujanos, que se considera una guía objetiva para realizar la anestesia espinal y las punciones de la columna circunspectivamente con menos posibilidades de provocar lesiones graves. Se llevó a cabo un estudio retrospectivo para determinar la ubicación del CM y cómo su nivel de terminación puede verse afectado por la edad, el sexo, la altura y una patología de la columna vertebral, la estenosis lumbar. El estudio incluyó 462 participantes que consistían en 199 hombres y 263 mujeres de 21 a 80 años de edad y una altura de entre 150-190 cm. Además, se incluyeron 150 pacientes con estenosis lumbar. La ubicación del CM se determinó mediante una serie de imágenes de resonancia magnética (RM) de la columna lumbosacra a diferentes niveles, incluidos T12, T12-L1, L1, L1-L2 y L2. Las mediciones revelaron diferencias considerables en el nivel de terminación de CM en relación con la edad, el sexo o la altura en una población de estudio saludable. Además, los resultados mostraron diferencias poco significativas en el nivel de terminación de CM entre hombres y mujeres, sanos o con estenosis espinal lumbar. En conclusión, se encontró que el nivel más común de terminación del CM es L1 seguido de L1-L2, considerándose seguro realizar procedimientos neuroaxiales lumbares a nivel de L3-L4.

Estudio comparativo entre placa-injerto, caja-placa y caja de PEEK en artrodesis de la columna cervical con conducto cervical estrecho / Comparative study between plate-graft, cage-plate and peek cage in cervical arthrodesis for cervical stenosis

Introducción: Se han desarrollado una variedad de sistemas para fijar y artrodesar la columna cervical con las ventajas de reducir del riesgo de seudoartrosis, extrusión y colapso del injerto, así como una mayor precisión en la alineación sagital, por tal motivo requerimos comparar resultados de placa-injerto, caja-placa y caja-PEEK, en pacientes con conducto cervical estrecho. Material y métodos: Estudio prospectivo, de intervención y comparativo, formando tres grupos: grupo I, artrodesis con placa-injerto, grupo II, caja-placa, grupo III, caja-PEEK. La evaluación funcional pre- y postoperatoria con escala de discapacidad cervical y escala visual análoga (EVA) de dolor y radiografías columna cervical. Se analizaron los resultados con pruebas no paramétricas de rangos con signo de Wilcoxon y Kruskal Wallis para comparación entre más de dos grupos. Con nivel de significancia de 0.05. Resultados: Muestra de 37 pacientes para el grupo I con n = 12, con 22 niveles; grupo II con: n = 11, con 19 niveles; grupo III con: n = 14 con 25 niveles. La mayoría de pacientes entre la sexta y octava década de la vida. Al año de postoperados el índice de discapacidad cervical y mejoría del dolor con EVA mostraron mejoría con diferencia estadística en los tres grupos (p = 0.001). Sin embargo, las mediciones radiográficas al año de seguimiento mostraron una mejoría significativa de la lordosis segmentaria (p = 0.02) sólo en pacientes operados con placa-injerto. Conclusiones: El uso de la placa injerto ofrece mejores resultados clínicos y radiográficos en comparación con la caja-placa y caja-PEEK al año de seguimiento.

Introduction: A variety of systems have been developed to fix and perform arthrodesis of the cervical spine, with the advantages of reducing the risk of pseudoarthrosis, extrusion and graft collapse and achieving a more precise sagittal alignment. We therefore need to compare the results of the following approaches to patients with cervical stenosis: plate-graft, cage-plate and PEEK cage. Material and methods: Prospective, interventional, comparative trial involving three groups: group I, arthrodesis with plate-graft; group II, cage-plate, and group III, PEEK cage. The pre- and postoperative assessments included the cervical disability scale, the pain visual analog scale (VAS), and cervical spine X-rays. The results were analyzed with non-parametric tests such as the Wilcoxon sign test and the Kruskal-Wallis test for the comparison of more than two groups. Significance level was 0.05. Results: The sample included a total of 37 patients: n = 12 in group I, with 22 levels; n = 11 in group II, with 19 levels, and n = 14 in group III, with 25 levels. Patient age ranged between 60 and 80. One year after surgery there was an improvement in cervical disability and the pain VAS score, with a statistically significant difference among the three groups (p = 0.001). However, radiographic measurements at that time showed a significant improvement in segmental lordosis (p = 0.02) only in plate-graft patients. Conclusions: The plate-graft approach provides better clinical and radiographic results compared to the cage-plate and PEEK cage techniques, at the one-year follow-up.

A New MRI Grading System for Cervical Foraminal Stenosis Based on Axial T2-Weighted Images

OBJECTIVE: The purpose of this study was to evaluate the reliability of a new magnetic resonance imaging (MRI) grading system for cervical neural foraminal stenosis (NFS). MATERIALS AND METHODS: Cervical NFS at bilateral C4/5, C5/6, and C6/7 was classified into the following three grades based on the T2-weighted axial images: Grade 0 = absence of NFS, with the narrowest width of the neural foramen greater than the width of the extraforaminal nerve root (EFNR); Grade 1 = the narrowest width of the neural foramen the same or less than (but more than 50% of) the width of the EFNR; Grade 2 = the width of the neural foramen the same or less than 50% of the width of the EFNR. The MRIs of 96 patients who were over 60 years old (M:F = 50:46; mean age 68.4 years; range 61-86 years) were independently analyzed by seven radiologists. Interobserver and intraobserver agreements were analyzed using the percentage agreement, kappa statistics, and intraclass correlation coefficient (ICC). RESULTS: For the distinction among the three individual grades at all six neural foramina, the ICC ranged from 0.68 to 0.73, indicating fair to good reproducibility. The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement. The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement. CONCLUSION: The new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.

Cauda equina redundant nerve roots are associated to the degree of spinal stenosis and to spondylolisthesis / Associação entre a presença de raízes redundantes na cauda equina e a área seccional do saco dural avaliada por meio de ressonância magnética

To evaluate the association of redundant nerve roots of cauda equina (RNRCE) with the degree of lumbar spinal stenosis (LSS) and with spondylolisthesis. Method After Institutional Board approval, 171 consecutive patients were retrospectively enrolled, 105 LSS patients and 66 patients without stenosis. The dural sac cross-sectional area (CSA) was measured on T2w axial MRI at the level of L2-3, L3-4 and L4-5 intervertebral discs. Two blinded radiologists classified cases as exhibiting or not RNRCE in MRI. Intra- and inter-observer reproducibility was assessed. Results RNRCE were associated with LSS. RRNCE was more frequent when maximum stenosis<55 mm2. Substantial intra- observer agreement and moderate inter-observer agreement were obtained in the classification of RNRCE. Spondylolisthesis was identified in 27 patients and represented increased risk for RRNCE. Conclusion LSS is a risk factor for RNRCE, especially for dural sac CSA<55 mm2. LSS and spondylolisthesis are independent risk factors for RNRCE. .

Avaliar associação entre raízes nervosas redundantes da cauda eqüina (RNRCE) com grau de estenose do canal lombar (ECL) e espondilolistese. Método Após aprovação do Comitê de Ética, 171 pacientes foram selecionados retrospectivamente, 105 com ECL e 66 sem estenose. Foram realizadas mensurações da área seccional do saco dural em imagens axiais de RM ponderadas em T2 em L2/L3, L3/L4 e L4/L5. Presença ou não de RRNCE foi classificada de forma independente por dois radiologistas, às cegas. Concordância intra e inter-observador foi analisada. Resultados RNRCE foi associada à ECL e foi mais freqüente quando a máxima estenose encontrada foi <55mm2. Houve grande concordância intra-observador e moderada inter-observador na classificação das RRNCE. Espondilolistese foi identificada em 27 pacientes e representou maior risco para desenvolvimento de RNRCE. Conclusão ECL é fator de risco para RNRCE, especialmente com áreas seccionais <55mm2. ECL e espondilolistese representam fatores de risco independentes para desenvolvimento de RNRCE. .

The Effect of Zoledronic Acid on the Volume of the Fusion-Mass in Lumbar Spinal Fusion

BACKGROUND: Few studies have explored the effects of bisphosphonates on bony healing in patients undergoing spinal fusion surgery. Most previous studies used animal models and found that bisphosphonate shows negative effects on spinal fusion consolidation. We intended to evaluate the effect of a single-dose of zoledronic acid on the volume of the fusion-mass in lumbar spinal fusion. METHODS: A retrospective review was carried out on 44 patients with symptomatic degenerative lumbar spinal stenosis who underwent one or two-level posterolateral fusion from January 2008 and January 2011. They were divided into 4 groups: group 1, autograft and zoledronic acid; group 2, allograft and zoledronic acid; group 3, autograft alone; and group 4, allograft alone. Functional radiography and three-dimensional computed tomography scans were used to evaluate and quantify the volume of the fusion-mass. The visual analog scale (VAS), the Oswestry disability index (ODI), and the short form 36 (SF-36) were used to evaluate the clinical outcomes. RESULTS: The mean volume of the fusion-mass per level was 8,814 mm3, 8,035 mm3, 8,383 mm3, and 7,550 mm3 in groups 1, 2, 3, and 4, respectively, but there were no significant differences between the groups (p = 0.829). There were no significant decreases in the volume of the fusion-mass (p = 0.533) in the zoledronic acid groups (groups 1 and 2). The VAS, the ODI, and the SF-36 at the 6-month follow-up after surgery were not significantly different (p > 0.05) among the 4 groups. The VAS, the ODI, and the SF-36 were not correlated with the volume of the fusion-mass (p = 0.120, 0.609, 0.642). CONCLUSIONS: A single dose of zoledronic acid does not decrease the volume of the fusion-mass in patients undergoing spinal fusion with osteoporosis. Therefore, we recommend that zoledronic acid may be used after spinal fusion in osteoporotic patients.

Changes in Spinal Canal Diameter and Vertebral Body Height with Age

PURPOSE: All structures of the spine, including the spinal canal, change continuously with age. The purpose of this study was to determine how the spinal canal of the lumbar spine changes with age. The L4/5 is the most common site of spinal stenosis and has the largest flexion-extension motion, whereas the T5/6 has the least motion. Therefore, we measured the spinal canal diameter and vertebral body height at T5, T6, L4, and L5 with age. MATERIALS AND METHODS: This was a retrospective study of aged 40 to 77 years. We reviewed whole spine sagittal MRIs of 370 patients with lumbar spinal stenosis (LSS) (Group 2) and 166 herniated cervical disc (HCD) (Group 1). Each group was divided into four age groups, and demographic parameters (age, gender, height, weight, BMI), the mid-spinal canal diameter, and mid-vertebrae height at T5, T6, L4, L5 were compared. Within- and between-group comparisons were made to evaluate changes by age and correlations were carried out to evaluate the relationships between all parameters. RESULTS: Height, weight, and all radiologic parameters were significantly lower in Group 2 than Group 1. Group 1 did not show any differences, when based on age, but in Group 2, height, weight, and T6, L4, and L5 height were significantly decreased in patients in their 70's than patients in their 40's, except for spinal canal diameter. Age was associated with all parameters except spinal canal diameter. CONCLUSION: Vertebral height decreased with age, but spinal canal diameter did not change in patients with either LSS or HCD. Mid-spinal canal diameter was not affected by aging.

Actualización en estenorraquis lumbar: diagnóstico, tratamiento y controversias / Spinal lumbar stenosis: An update

Spinal lumbar stenosis is a disease that occurs mainly between the 5th and 7th decade of life and can be congenital or acquired. The latter has many etiologies, but a degenerative cause is the most common. Stenosis is a narrowing of the spinal canal diameter caused by many factors such as bulging discs, hypertrophy of flavum ligament, facet capsule thickening and osteophyte formation. The classical symptom of the disease is sciatic pain, that improves with lumbar flexion and worsens with ambulation. Neurological examination is often normal and the most useful imaging test is magnetic resonance imaging (MRI). Conservative management consists in non-steroidal anti-inflammatory drugs, muscle relaxants, physical therapy and epidural - radicular infiltrations. Spinal infiltrations have a proven efficacy for pain management. A good result of this therapy predicts a favorable outcome after surgery. Surgical treatment consists in decompression with or without lumbar fusion. The addition of an arthrodesis is recommended for degenerative spondylolisthesis, correction of deformities, recurrent spinal stenosis with instability, sagittal or coronal imbalance and adjacent segment disease.

Comparison of Magnetic Resonance Imaging and Computed Tomography-Myelography for Quantitative Evaluation of Lumbar Intracanalar Cross-Section

PURPOSE: A comparison of MRI and computed tomography-myelography (CTM) for lumbar intracanalar dimensions. To compare the capability and reproducibility of MRI and CTM in measuring the cross-sectional morphology of intracanalar lesions of the lumbar spine. MATERIALS AND METHODS: MRI and CTM of lumbar disc levels from 61 subjects with various lumbar spinal diseases were studied. Dural area, dural anteroposterior (AP) diameter, dural right-left diameter, and thickness of the ligamentum flavum were measured by two orthopedic surgeons. Each section was graded by degree of stenosis. Absolute value and intra- and inter-observer correlation coefficients (ICC) of these measurements and the associations between MRI and CTM values were determined. RESULTS: Except for MRI determination of ligament flavum thickness, CTM and MRI and intra- and ICC suggested sufficient reproducibility. When measurements of dural area, dural AP diameter, and RL diameter were compared, values in CTM were significantly (p = 0.01-0.004) larger than those in MRI (CTM/MRI ratios, 119%, 111%, and 105%, respectively). As spinal stenosis became more severe, discrepancies between CTM and MRI in measurements of the dural sac became larger. CONCLUSION: Both CTM and MRI provided reproducible measurements of lumbar intracanalar dimensions. However, flavum thickness may be more accurately measured by CTM. Because the differences in the measurements between CTM and MRI are very slight and there is very little data to suggest that the precise degree of stenosis is related to symptoms or treatment outcome, the usefulness of the CTM over MRI needs to be confirmed in future studies.

The Relationship between Spinal Stenosis and Neurological Outcome in Traumatic Cervical Spine Injury: An Analysis using Pavlov's Ratio, Spinal Cord Area, and Spinal Canal Area

BACKGROUND: This study examined the relationship between four radiological parameters (Pavlov's ratio, sagittal diameter, spinal cord area, and spinal canal area) in patients with a traumatic cervical spine injury, as well as the correlation between these parameters and the neurological outcome. METHODS: A total of 212 cervical spinal levels in 53 patients with a distractive-extension injury were examined. The following four parameters were measured: Pavlov's ratio on the plain lateral radiographs, the sagittal diameter, the spinal cord area, and the spinal canal area on the MRI scans. The Pearson correlation coefficients between the parameters at each level and between the levels of each parameter were evaluated. The correlation between the radiological parameters and the spinal cord injury status classified into four categories, A (complete), B (incomplete), C (radiculopathy), and D (normal) was assessed. RESULTS: The mean Pavlov's ratio, sagittal diameter, spinal cord area and spinal canal area was 0.84, 12.9 mm, 82.8 mm2 and 236.8 mm2, respectively. An examination of the correlation between the radiological spinal stenosis and clinical spinal cord injury revealed an increase in the values of the four radiological parameters from cohorts A to D. Pavlov's ratio was the only parameter showing statistically significant correlation with the clinical status (p = 0.006). CONCLUSIONS: There was a correlation between the underlying spinal stenosis and the development of neurological impairment after a traumatic cervical spine injury. In addition, it is believed that Pavlov's ratio can be used to help determine and predict the neurological outcome.

The size of the vertebral canal and the significance of epidural fat in lumbar spinal stenosis.

Measurements of mid sagittal diameter (MSD) and interpedicular diameter (IPD) in patients operated on for central lumbar spinal stenosis were compared to the control group. Both groups can be matched in terms of gender and age. We found that in the stenotic patients the MSD and the IPD were smaller than in the control group, all of the measurements except the IPD in male stenotic patients was statistically different. Sagittal and axial MR images of the stenotic patients were used to evaluate the status of the posterior epidural fat which was graded as normal, small, very small and absent. All the patients were surgically treated for lumbar stenosis, imaging studies and intraoperative finding were correlated. Reduction or absence of the posterior epidural fat (PEF) by the imaging studies were found to be related to the intraoperative findings and the duration of symptoms. PEF may be used as an intraoperative indicator for optimal surgical decompression.

Estenosis del canal espinal lumbar / Stenosis of the spinal lumbar chanel

Para la realización de este trabajo se revisaron 176 historias clínicas de pacientes con patología lumbar, de los cuales 47, tenían diagnóstico de estenosis del canal espinal lumbar. Los pacientes fueron tratados quirúrgicamente por el Servicio de Neurocirugía del Hospital Universitario de Caracas, durante los años 1988-1992. La causa que más frecuentemente motivó a los pacientes a consultar fué: lumbociatalgia: 36 casos (76,59); seguido por lumbalgia: 8 casos (17,02); paraparesia: 7 casos (14,89); parestesias: 4 casos (8,51); retención urinaria: 3 casos (6,38); claudicación neurogénica: 2 casos (4,25); y otras causas como lumbosacralgia y atrofia muscular: 1 caso cada uno (2,12). Los estudios imagenológicos realizados en los pacientes fueron: radiología simple: 31 casos (65,95), en donde se observaron cambios degenerativos de la columna lumbar, dados por osteofitos, disminución del interespacio, esclerosis de los platillos vertebrales y espondilolistesis. Mielografía 23 casos observándose disminución del diá anteroposterior (bloqueo parcial o total), amputación de raíces, disminución del diámetro transverso. Mielotomografía 18 casos evidenciándose disminución de los diámetros anteroposterior transverso, hipertrofia de facetas articulares, osteofitos. Resonancia magnética 6 casos visualizándose protrusión del disco invertebrado, hipertrofia del ligamento amarillo, disminución de la grasa peridural, del diámetro del foramen neural y cambios en la señal del disco invertebrado. La electromiografía fué el único test electrofisiológico realizado en 33 casos. Todos los pacientes se trataron médicamente en el preoperatorio, con AINES. El tratamiento quirúrgico practicado fué: laminectomía más foraminotomía: 26 casos; laminectomía multinivel: 7 casos; laminectomía en un sólo nivel: 6 casos; foraminotomía 3 casos. Algunos pacientes requirieron estabilización espinal, la cual se efectúo de la siguiente manera descompresiva más fusiones 2 casos, descompresiva más instrumentación espinal 3 casos. Entre los hallazgos intraoperatorios más frecuentes se tuvo: hipertrofia del ligamento amarillo 26 casos; hipertrofia de facetas articulares 13 casos; hernia discal 16 casos; espondilolistesis 7 casos; osteofitos 6 casos; LOE estradural 5 casos; hipertrofia de las láminas 2 casos, ausencia de grasa epidural 1 caso. Las complicaciones observadas, fueron escasas, de 47 pacientes 39 casos no presentaron complicaciones, fístula de LCR 2 casos; lesión de raíz nerviosa, disminución de la fuerza muscular, infección de la herida, deshiciencia de sutura y muerte 1 caso cada uno. De los 47 pacientes, 41 casos evolucionaron satisfactoriamente, 6 pacientes persistieron con sintomatología neurológica.

Fenestración subarticular multinivel en las estenosis del canal espinal. Comunicación preliminar / Subarticular multilevel fenestration in the stenosis of the spinal canal: Preliminary communication

Es bien sabido que las amplias laminectomías en las raquiestenosis pueden producir inestabilidad espinal futura; la técnica ya conocida como fenestración subarticular toma en cuenta dicha inestabilidad y produce las descomprensiones adecuadas en los verdaderos niveles existentes, tales como el nivel inter-espacio y las estenosis del canal radicular, preservando el tercio superior de las láminas, las apófisis espinosas y sus ligamentos. En caso de inestabilidad presente, se une esta técnica a los implantes tipo Cotrel Dobousset (C-D), Roy-Camille y otros. Presentamos ocho casos con dicha técnica