Intraoperative Motor Evoked Potential Improvement in Cervical Spondylotic Myelopathy: Comparison of Cortical Stimulation Parameters

Diffusion Metrics as a Potential Prognostic Biomarker in Cervical Myelopathy

Diffusion tensor imaging (DTI) has a diagnostic value in cervical myelopathy. The usefulness of diffusion metrics as a potential prognostic biomarker was assessed in this review. Various diffusion metrics, such as fractional anisotropy, mean diffusivity, apparent diffusion coefficient, and radial diffusivity, were significant in correlation with functional recovery after surgery. Changes in diffusion metrics not only at the compression level, but also above and below the compression level were confirmed. However, it was difficult to confirm the results owing to the diversity of studies. Further efforts to make a consensus on spinal cord DTI are needed.

Analysis of Preoperative Factors Affecting Postoperative Spinal Canal Expansion after Posterior Decompression for the Treatment of Multilevel Cervical Myelopathy / 대한척추외과학회지

STUDY DESIGN: Retrospective analysis OBJECTIVES: To evaluate preoperative factors related with spinal canal expansion after posterior decompression for the treatment of multilevel cervical myelopathy. SUMMARY OF LITERATURE REVIEW: Data about preoperative factors related with spinal canal expansion after posterior cervical decompression surgery are inconsistent. MATERIALS AND METHODS: We reviewed 67 patients with cervical myelopathy who underwent posterior laminectomy or laminoplasty. Radiologically, we evaluated the C2-7 Cobb angle and range of motion using X-rays from the preoperative assessment and final follow-up. Expansion of the spinal canal at 6 weeks postoperatively was evaluated using magnetic resonance imaging and compared with the preoperative values. The preoperative factors of age, sex, number of operated levels, operation method, and radiological parameters were investigated as factors potentially related to postoperative spinal canal expansion using multivariate regression and correlation analyses. The clinical outcome was analyzed by the Neck Disability Index (NDI) and Japanese Orthopaedic Association (JOA) scores. RESULTS: The postoperative spinal canal expansion was 4.76 mm in sagittal images and 4.31 mm in axial images, with higher values observed in males and cases of severe preoperative cord compression. A lordotic preoperative Cobb angle was related to postoperative spinal canal expansion and JOA score improvement, but without statistical significance. The clinical outcomes of NDI (18.3→14.8) and JOA scores (10.81→14.6) showed improvement, but were not significantly related with any preoperative factors. CONCLUSIONS: The amount of preoperative spinal canal stenosis was associated with postoperative spinal canal expansion after posterior decompression in multilevel cervical myelopathy. The preoperative Cobb angle was not related to postoperative spinal canal expansion or clinical improvement.

A Case of Quadriplegia after Parotidectomy in a Patient with Asymptomatic Cervical Spondylosis / 대한이비인후과학회지

Cervical spondylosis is a common degenerative disease of the cervical spine affecting the cervical vertebral bodies and intervertebral discs. During parotidectomy, the patient is placed in a supine position with the neck extended and head rotated to the contralateral side. This position could exacerbate pre-existing cervical spondylosis and cause cervical myelopathy. We present a case of postoperative quadriplegia secondary to cervical myelopathy after parotidectomy. A 68-year-old man without symptoms of cervical spondylosis underwent partial parotidectomy for a right parotid mass and subsequently developed quadriplegia 8 hours postoperatively. Magnetic resonance imaging revealed severe cervical myelopathy. Emergency laminoplasty was performed, and steroid therapy was initiated. He showed near-complete recovery six months later.

A Brazilian Portuguese cross-cultural adaptation of the modified JOA scale for myelopathy

OBJECTIVES: To develop a version of the modified Japanese Orthopaedic Association (mJOA) scale that had been translated into Portuguese and cross-culturally adapted for the Brazilian population. METHODS: The well-established process of forward-backward translation was employed along with cross-cultural adaptation. RESULTS: Three bilingual translators (English and native Portuguese) performed the forward translation of the mJOA scale from English to Portuguese based on iterative discussions used to reach a consensus translation. The translated version of the mJOA scale was then back-translated into English by a native English-speaking translator unaware of the concepts involved with the mJOA scale. The original mJOA scale and the back-translated version were compared by a native North American neurosurgeon, and as they were considered equivalent, the final version of the mJOA scale that had been translated into Portuguese and cross-culturally adapted was defined. CONCLUSION: To facilitate global and cross-cultural comparisons of the severity of cervical myelopathy, this study presents a version of the mJOA scale that was translated into Portuguese and cross-culturally adapted for the Brazilian population.

Anterior controllable anteriodisplacement and fusion for treatment of severe cervical ossification of posterior longitudinal ligament / 第二军医大学学报

Objective To report a novel technique named anterior controllable antedisplacement and fusion (ACAF) for the treatment of severe ossification of the posterior longitudinal ligament of the cervical spine, which allows for direct decompression of the nerve without resection of the ossification, making up for deficiencies in traditional anterior or posterior decompression. Methods The main surgical procedures of the ACAF included treatment of intervertebral space, removal of the anterior part of vertebrae, installation of titanium plate and interbody fusion cages, bilateral osteotomies of the vertebrae, and antedisplacement of the vertebrae ossification complex. The clinical data of two patients undergoing this surgery for severe ossification of the posterior longitudinal ligament of cervical spine were collected and analyzed. Results ACAF enabled direct decompression of spinal cord and nerve root through antedisplacement of the vertebrae ossification complex. The two patients who underwent ACAF gained satisfactory restoration with decompression of spinal cord and good recovery of neurological function, with no specific complications. Conclusion ACAF surgery takes into account the effectiveness of anterior direct decompression and the safety of posterior indirect decompression. Preliminary results shows that it can be used for severe cervical ossification of the posterior longitudinal ligament.

Anterior controllable anteriodisplacement and fusion for treatment of severe cervical ossification of posterior longitudinal ligament / 第二军医大学学报

Objective To report a novel technique named anterior controllable antedisplacement and fusion (ACAF) for the treatment of severe ossification of the posterior longitudinal ligament of the cervical spine,which allows for direct decompression of the nerve without resection of the ossification,making up for deficiencies in traditional anterior or posterior decompression.Methods The main surgical procedures of the ACAF included treatment of intervertebral space,removal of the anterior part of vertebrae,installation of titanium plate and interbody fusion cages,bilateral osteotomies of the vertebrae,and antedisplacement of the vertebrae ossification complex.The clinical data of two patients undergoing this surgery for severe ossification of the posterior longitudinal ligament of cervical spine were collected and analyzed.Results ACAF enabled direct decompression of spinal cord and nerve root through antedisplacement of the vertebrae ossification complex.The two patients who underwent ACAF gained satisfactory restoration with decompression of spinal cord and good recovery of neurological function,with no specific complications.Conclusion ACAF surgery takes into account the effectiveness of anterior direct decompression and the safety of posterior indirect decompression.Preliminary results shows that it can be used for severe cervical ossification of the posterior longitudinal ligament.

Correlation between Preoperative Magnetic Resonance Imaging Signal Intensity Changes and Clinical Outcomes in Patients Surgically Treated for Cervical Myeloradiculopathy

STUDY DESIGN: This was a single surgeon, single center-based retrospective study with prospective data collection. PURPOSE: To assess the correlation between T2-weighted magnetic resonance imaging (MRI) signal intensity (SI) changes and factors such as age, duration of symptoms, baseline modified Japanese Orthopedic Association (mJOA) score and to determine its prognostic value in predicting recovery after surgery. OVERVIEW OF LITERATURE: Whether intramedullary cord T2-weighted MRI SI changes can predict operative outcomes of cervical myeloradiculopathy remains debatable, with only a few prospective studies analyzing the same. METHODS: Forty-six consecutive patients who underwent cervical myeloradiculopathy were included and were followed up for an average of 1 year. Preoperative T2-weighted MRI SI grading was performed for all patients. The correlation between MRI SI changes and age, duration of symptoms, preoperative mJOA score, and mJOA score at 1-year follow-up were analyzed. RESULTS: Fifteen patients had single-level (21.73%) or double-level (10.86%) prolapsed discs; 54.34% had degenerative cervical spondylosis with canal stenosis or multilevel disc prolapse and 13.07% had ossified posterior longitudinal ligaments. The mean age was 56.17±9.53 years (range, 35–81 years). The mean baseline mJOA score was 10.83±2.58 (range, 6–16), which postoperatively improved to 13.59±2.28 (range, 8–17; p<0.001). There was a statistically significant correlation between mJOA score at 1 year and MRI T2 SI grading (p=0.017). CONCLUSIONS: Patients with longer symptom durations had high grades of intramedullary cord T2-weighted MRI SI changes. Age and preoperative neurological status were not significantly correlated with the existence of intramedullary cord SI changes. However, patients without or with mild and diffuse intramedullary cord T2-weighted MRI SI changes had better postoperative neurological recovery than those with sharp and focal SI changes.

Does Segmental Kyphosis Affect Surgical Outcome after a Posterior Decompressive Laminectomy in Multisegmental Cervical Spondylotic Myelopathy?

STUDY DESIGN: Retrospective analysis. PURPOSE: To compare results of laminectomy in multisegmental compressive cervical myelopathy (CSM) with lordosis versus segmental kyphosis. OVERVIEW OF LITERATURE: Laminectomy is an established procedure for decompression in CSM with cervical lordosis. However in patients with segmental kyphosis, it is associated with risk of progression of kyphosis and poor outcome. Whether this loss of sagittal alignment affects functional outcome is not clear. METHODS: We retrospectively reviewed 68 patients who underwent laminectomy for CSM from 1998 to 2009. As per preoperative magnetic resonance images, 36 patients had preoperative lordosis (Group 1) and 32 had segmental kyphosis (Group 2). We studied age at the time of surgery, duration of preoperative symptoms, recovery rate, magnitude of postoperative backward shifting of spinal cord and loss of sagittal alignment. RESULTS: Mean follow up was 5.05 years (range, 2–13 years) and mean age at the time of surgery 61.88 years. Group 1 had 20 men and 16 women and Group 2 had 19 men and 13 women. Mean recovery rate in Group 1 was 60.32%, in Group 2 was 63.7% without any statistical difference (p-value 0.21, one tailed analysis of variance). Two patients of Group 1 had loss of cervical lordosis by five degrees. In Group 2 seven patients had progression of segmental kyphosis by 5–10 degrees and two patients by more than 10 degrees. Mean cord shift was more in Group 1 (mean, 2.41 mm) as compared to Group 2 (mean, –1.97 mm) but it had no correlation to recovery rate. Patients with younger age (mean, 57 years) and less duration of preoperative symptoms (mean, 4.86 years) had better recovery rate (75%). CONCLUSIONS: Clinical outcome in CSM is not related to preoperative cervical spine alignment. Thus, lordosis is not mandatory for planning laminectomy in CSM. Good outcome is expected in younger patients operated earliest after onset of symptoms.

Management of degenerative cervical myelopathy - An update / Manejo da mielopatia cervical degeneratiiva - Uma atualização

SUMMARY Introduction Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction in adult patients. Patients generally present with a slow, progressive neurological decline or a stepwise deterioration pattern. In this paper, we discuss the most important factors involved in the management of DCM, including a discussion about the surgical approaches. Method The authors performed an extensive review of the peer-reviewed literature addressing the aforementioned objectives. Results Although the diagnosis is clinical, magnetic resonance imaging (MRI) is the study of choice to confirm stenosis and also to exclude the differential diagnosis. The severity the clinical symptoms of DCM are evaluated by different scales, but the modified Japanese Orthopedic Association (mJOA) and the Nürick scale are probably the most commonly used. Spontaneous clinical improvement is rare and surgery is the main treatment form in an attempt to prevent further neurological deterioration and, potentially, to provide some improvement in symptoms and function. Anterior, posterior or combined cervical approaches are used to decompress the spinal cord, with adjunctive fusion being commonly performed. The choice of one approach over the other depends on patient characteristics (such as number of involved levels, site of compression, cervical alignment, previous surgeries, bone quality, presence of instability, among others) as well as surgeon preference and experience. Conclusion Spine surgeons must understand the advantages and disadvantages of all surgical techniques to choose the best procedure for their patients. Further comparative studies are necessary to establish the superiority of one approach over the other when multiple options are available.

RESUMO Introdução a mielopatia cervical degenerativa (MCD) é uma das causas mais comuns de disfunção medular em adultos. Os pacientes em geral apresentam declínio neurológico lento e progressivo, ou deterioração escalonada. No presente artigo, discutimos os mais importantes fatores envolvidos no manejo da MCD, incluindo considerações sobre os aspectos relacionados à escolha da abordagem cirúrgica. Método realizou-se extensa revisão da literatura de artigos peer-reviewed relacionados ao tema. Resultados embora o diagnóstico seja realizado clinicamente, a ressonância magnética (RM) é o estudo de imagem de escolha para confirmá-lo e excluir eventuais diagnósticos diferenciais. A gravidade do quadro clínico pode ser avaliado utilizando-se diferentes escalas, como a modified Japanese Orthopedic Association (mJOA) ou a de Nürick, provavelmente as mais comuns. Uma vez que a melhora clínica espontânea é rara, a cirurgia é a principal forma de tratamento, em uma tentativa de evitar dano neurológico adicional ou deterioração e, potencialmente, aliviar alguns sintomas e melhorar a função dos pacientes. Abordagens cirúrgicas por via anterior, posterior ou combinada podem ser usadas para descomprimir o canal, concomitantemente a técnicas de fusão. A escolha da abordagem depende das características dos pacientes (número de segmentos envolvidos, local de compressão, alinhamento cervical, cirurgias prévias, qualidade óssea, presença de instabilidade, entre outras), além da preferência e experiência do cirurgião. Conclusão os cirurgiões de coluna devem compreender as vantagens e desvantagens de todas as técnicas cirúrgicas para escolher o melhor procedimento para seus pacientes. Estudos futuros comparando as abordagens são necessários para orientar o cirurgião quando múltiplas opções forem possíveis.

Cervical Myelopathy Caused by Engorgement of the Epidural Venous Plexus due to Cerebrospinal Fluid Overdrainage: Case Report and Review of the Literature

This is a case report of a 33-year-old woman with cervical myelopathy caused by an enlargement of the cervical venous plexus, after she was submitted to a ventriculoperitoneal (VP) shunt that evolved to overdrainage. Magnetic Resonance Imaging (MRI) revealed an epidural venous enlargement within the spinal channel, with a 50% narrowing from C2 to C5, and spinal cord compression. A shunt revision was performed using a programmable drainage system, and a second MRI revealed the absence of the venous enlargement, resulting in cervical spinal cord decompression and remission of neurological symptoms. Compressive myelopathy consequent to the enlargement of the epidural venous plexus related to the overdrainage of the ventriculoperitoneal shunt system without typical signs of intracranial hypotension may result in misleading etiological diagnoses. Acknowledging this disorder is important to distinguish it from neoplastic processes or hematomas, for which surgical intervention may be needed.

Este é um relato de caso de uma paciente de 33 anos de idade que apresentou mielopatia cervical devido a alargamento do plexo venoso cervical, após ser submetida a uma derivação ventriculoperitoneal que evoluiu com hiperdrenagem. Exame de Ressonância Nuclear Magnética (RNM) revelou alargamento do plexo venoso epidural no canal espinhal, com estreitamento de 50% em C2 a C5, e compressão da medula espinhal. Uma revisão da derivação foi feita com um sistema de drenagem programável, e uma segunda RNM revelou ausência de ingurgitamento venoso, resultando em descompressão medular e remissão dos sintomas neurológicos. Mielopatia compressiva consequente ao alargamento do plexo venoso epidural relacionado à hiperdrenagem do sistema de derivação ventriculoperitoneal sem sinais típicos de hipotensão intracraniana pode resultar em diagnósticos incorretos. O conhecimento dessa patologia é importante para distingui-la de processos neoplásicos ou hematomas, nos quais intervenções cirúrgicas podem ser necessárias.

Addressing Stretch Myelopathy in Multilevel Cervical Kyphosis with Posterior Surgery Using Cervical Pedicle Screws

STUDY DESIGN: Technique description and retrospective data analysis. PURPOSE: To describe the technique of cervical kyphosis correction with partial facetectomies and evaluate the outcome of single-stage posterior decompression and kyphosis correction in multilevel cervical myelopathy. OVERVIEW OF LITERATURE: Kyphosis correction in multilevel cervical myelopathy involves anterior and posterior surgery. With the advent of cervical pedicle screw-rod instrumentation, single-stage posterior kyphosis correction is feasible and can address stretch myelopathy by posterior shortening. METHODS: Nine patients underwent single-stage posterior decompression and kyphosis correction for multilevel cervical myelopathy using cervical pedicle screw instrumentation from March 2011 to February 2014 and were evaluated preoperatively and postoperatively with modified Japanese Orthopaedic Association (mJOA) scoring and computed tomography scans for radiological measurements. Kyphosis assessment was made with Ishihara curvature index and C2–C7 Cobb's angle. The linear length of the spinal canal and the actual spinal canal length were also evaluated. The average follow-up was 40.56 months (range, 20 to 53 months). RESULTS: The average preoperative C2–7 Cobb's angle of 6.3° (1° to 12°) improved to 2° (10° to −9°). Ishihara index improved from −15.8% (−30.5% to −4.7%) to −3.66% (−14.5% to +12.6%). The actual spinal canal length decreased from 83.64 mm (range, 76.8 to 91.82 mm) to 82.68 mm (range, 75.85 to 90.78 mm). The preoperative mJOA score of 7.8 (range, 3 to 11) improved to 15.0 (range, 13 to 17). CONCLUSIONS: Single-stage posterior decompression and kyphosis correction using cervical pedicle screws for multilevel cervical myelopathy may address stretch myelopathy, in addition to decompression in the transverse plane. However, cervical lordosis was not achieved with this method as predictably as by the anterior approach. The present study shows evidence of mild shortening of cervical spinal canal and a positive correlation between canal shortening and clinical improvement.

Cervical Footprint Anthropometry in Indian Population: Implications on Design of Artificial Disc Replacement Devices

STUDY DESIGN: Cross-sectional study. PURPOSE: To accurately measure the dimensions of cervical endplates based on computed tomography (CT) scans in Indian population and assess accuracy of match with currently available cervical disc prostheses. OVERVIEW OF LITERATURE: The dimensions of currently available cervical disc replacement implants are based on early published geometrical measurements of vertebrae endplates for Caucasian population. To author's knowledge, similar study has not been published for patients from Indian subcontinent. METHODS: CT scans of cervical spine of patients from Indian subcontinent were collected and reviewed. Seventy patients (54 men and 16 women; aged 18-56 years with average of 37 years) who underwent CT scans of cervical spine were included in study. 3D CT scans of sub axial cervical spine (C3 to C7) were analyzed. The anterior-posterior (AP) and central mediolateral (CML) dimensions of superior and inferior endplates from C3 to C7 were measured using digital measuring system. RESULTS: A total of 560 endplates of 70 patients were included in the study. The AP diameter of cervical endplates ranged from 0.87 to 2.47 cm. The CML diameters ranged from 0.84 to 2.98 cm. For levels C3/C4 and C4/C5 for AP dimension Prestige-LP (90.5%) and Prodisc-C (89%) discs showed higher percentage of matching than Discover discs (58.5%). For CML diameter, Prestige-LP (69.5%), Prodisc-C (70%) and Discover (39.5%) discs showed almost similar matching with measured endplates. For levels C5/C6 and C6/C7 for AP dimension, Prestige-LP (67.25%), Prodisc-C (49.35%) and Discover (51.5%) discs showed similar matching. For CML diameter Prestige-LP (32%), Prodisc-C (27.5%) and Discover (42.2%) discs showed poor matching with measured endplates. CONCLUSIONS: This study indicates need for redesign of cervical disc prostheses to match Indian patients. The collected anthropometric dimensions from this study may be used to design and develop indigenous artificial total disc replacement prosthesis and even cervical cages in India. With the present study being a small pilot study, the authors recommend anthropometric CT measurements in larger number of Indian patients in order to validate footprint dimensions for designing better-matched prosthesis.

Sensitivity of Pyramidal Signs in Patients with Cervical Spondylotic Myelopathy

STUDY DESIGN: This was a retrospective study. PURPOSE: The purpose of this study was to study the relationship between prevalence of pyramidal signs and the severity of cervical myelopathy. The study is focused on patients having increased signal intensity in T2-weighted magnetic resonance imaging. OVERVIEW OF LITERATURE: Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction in elderly population. It is the consequence of spondylotic changes leading to cervical cord injury with resulting clinical deficits. Diagnosis in such patients is made based on clinical and radiographic features. A patient must have both symptoms and signs consistent with cervical cord injury as well as radiographic evidence of damage to spondylotic cord. METHODS: Forty-six patients with complaint of cervical spondylotic myelopathy with increased signal intensity in T2-weighted magnetic resonance imaging were included in the study. The neurological finding of the patients was reviewed for the presence of pyramidal signs. The prevalence of each pyramidal sign was calculated and correlated to severity of cervical myelopathy. The motor function scores of the upper and lower extremities for cervical myelopathy set by the Japanese Orthopedic Association (motor Japanese Orthopaedic Association score, m-JOA) scores were used to assess severity of myelopathy. RESULTS: The most prevalent signs were hyperreflexia (89.1%), Hoffmann reflex (80.4%), Babiniski sign (56.5%), and ankle clonus (39.1%). Babiniski sign, ankle clonus, and Hoffmann reflex showed significant association with the lower m-JOA score. CONCLUSIONS: In patients with cervical myelopathy, hyperreflexia exhibited highest sensitivity whereas ankle clonus demonstrated lowest sensitivity. The prevalence of the pyramidal signs is correlated with increasing severity of myelopathy.

Kyphotic Neck and Correlation With Clinical Outcomes

STUDY DESIGN: A literature review regarding the correlation between a kyphotic neck and its clinical outcomes. OBJECTIVES: This review examines normal cervical alignment, methods for assessing alignment, a specific correlation between kyphotic neck and clinical outcomes, and indications and methods of surgical treatment. SUMMARY OF LITERATURE REVIEW: Cervical kyphotic deformity is problematic in terms of HRQOL due to nerve damage or loss of horizontal gaze. MATERIALS AND METHODS: Review of the literature. RESULTS: Cervical kyphosis can be caused by postlaminectomy, degenerative disc disease, and trauma, and the symptoms exhibit diverse clinical progression including compensatory mechanisms, adjacent segment disease, changes in quality of life, and cervical myelopathy. Given the serious complications of cervical surgery, we need a deep understanding of spine anatomy, preoperative planning, and correction methods. CONCLUSIONS: It is vital to investigate cervical sagittal alignment and to perform intensive treatment and corrective surgery to achieve better clinical outcomes.

Compression Angle of Ossification of the Posterior Longitudinal Ligament and Its Clinical Significance in Cervical Myelopathy

OBJECTIVES: The correction of clinical and radiologic abnormalities in patients with symptomatic ossification of the posterior longitudinal ligament (OPLL) is the current mainstay of treatment. This study aimed to identify radiographic predictors of severity of myelopathy in patients with symptomatic OPLL. METHODS: Fifty patients with symptomatic cervical OPLL were enrolled. Based on Japanese Orthopedic Association (JOA) scores, patients were divided into either the mild myelopathy (n=31) or severe myelopathy (n=19) group. All subjects underwent preoperative plain cervical roentgenogram, computed tomography (CT), and MR imaging (MRI). Radiological parameters (C2–7 sagittal vertical axis, SVA; C2–7 Cobb angle; C2–7 range of motion, ROM; OPLL occupying ratio; and compression angle) were compared. Compression angle of OPLL was defined as the angle between the cranial and caudal surfaces of OPLL at the maximum level of cord compression RESULTS: The occupying ratio of the spinal canal, C2–7 Cobb angle, C2–7 SVA, types of OPLL, and C2–7 ROM of the cervical spine were not statistically different between the two groups. However, the OPLL compression angle was significantly greater (p=0.003) in the severe myelopathy group than in the mild myelopathy group and was inversely correlated with JOA score (r=-0.533, p<0.01). Furthermore, multivariate regression analysis demonstrated that the compression angle (B=-0.069, p<0.001) was significantly associated with JOA scores (R=0.647, p<0.005). CONCLUSION: Higher compression angles of OPLL have deleterious effects on the spinal cord and decrease preoperative JOA scores.

A Comparison of Implants Used in Double Door Laminoplasty : Allogeneic Bone Spacer versus Hydroxyapatite Spacer

OBJECTIVE: The aim of this study was to compare the clinical and radiological outcomes associated with the use of hydroxyapatite (HA) spacer and allogeneic bone (AB) spacer in laminoplasty. METHODS: From January 2006 to July 2014, 79 patients with cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament underwent cervical laminoplasty. The radiologic parameters were obtained from plain radiography and three-dimensional computed tomography. All images were taken before and after surgery. Cervical lordosis, spinal canal dimension, fusion between lamina and spacer, and resorption of spacer were checked. Clinical outcomes were assessed using visual analog scale and Japanese Orthopedic Association. RESULTS: Double-door laminoplasty was performed on 280 levels : 182 in the HA group and 98 in the AB group. The mean follow-up was 23.1 months (range : 4–69 months). Similar fusion rates were found in these groups (p=0.3). The resorption rate between lamina and spacer was lower in the HA group (p<0.001). During the immediate postoperative period, the canal dimension of both groups increased compared with the results in the preoperative period. However, the canal dimension of the AB group decreased over time compared with that of the HA group (p<0.001). CONCLUSION: Double-door laminoplasty improved the clinical outcomes of both groups. However, the spinal canal dimension in the AB group showed a greater degree of reduction than in the HA group at the final postoperative follow-up. Therefore, we suggest that surgeons consider the use of larger-sized AB spacers in double-door laminoplasties.

Screw Back-Out Following "Open-Door" Cervical Laminoplasty: A Review of 165 Plates

STUDY DESIGN: Retrospective study. PURPOSE: To investigate safety profile of open door laminoplasty plates. OVERVIEW OF LITERATURE: Few reports have documented potential complications related to the use of cervical laminoplasty plates. METHODS: Records and radiographs of consecutive plated laminoplasty patients of one academic surgeon were analyzed. Group 1 had screw back-out, defined as change in screw position, and group 2 did not. RESULTS: Forty-two patients (mean age, 56.9) underwent "open-door" cervical laminoplasty using 165 plates. Mean follow-up was 24 months (range, 12-49 months). Mean Nurick grade improved from 2.1 to 0.9 postoperatively. Cervical lordosis (C2-7) was 12.1degrees preoperatively and 10.0degrees postoperatively. Range-of-motion was 27.0degrees preoperatively and 23.4degrees postoperatively. Partial screw back-out was noted in 27 of 165 plates (16.4%) and in 34 of 660 screws (5.2%). Of the 34 screws, 27 (79.4%) were at either the most cranial (12/27, 44.4%) or the most caudal (15/27, 55.5%) level. Cranially, 11/12 screws (91.7%) had back-out. Caudally, 9/15 lateral mass screws (60.0%) backed-out versus 6 laminar screws (40.0%). Of the 22 patients with screw back-out, 15 (68.2%) occurred <3 months postoperative and 6 (27.3%) occurred 4-12 months postoperative. No statistical differences were found between group 1 and 2 for age, gender, preoperative and postoperative lordosis, focal sagittal alignment, range-of-motion, or Nurick grade. Despite screw backout in 22 patients, there were no plate dislodgements, laminoplasty closure, or neurological deterioration. CONCLUSIONS: Although screw back-out may occur with the use of cervical laminoplasty plates, the use of these plates without a bone block appears to be safe and reliable. As screw back-out is most common at the cranial and caudal ends of the laminoplasty, we recommend using the maximum number of screws (typically 2 for the lateral mass and 2 for the spinous process) at these levels to secure the plate to the bone.

Suspicious Reperfusion Injury of Spinal Cord After Multilevel Cervical Posterior Decompression without Remarkable Surgical Insult: Two Case Reports

STUDY DESIGN: Two case reports. OBJECTIVES: We present two cases of quadriplegia after posterior decompression with fusion caused by a suspicious reperfusion injury of spinal cord without remarkable surgical insult. SUMMARY OF LITERATURE REVIEW: Posterior decompression and posterolateral fusion have been reported as effective procedures in patients with multilevel myelopathy. However, postoperative spinal cord injury without remarkable intraoperative technical damage has been reported in a few articles. Reperfusion mechanism was suggested as one of the leading causes and reported in some animal models. MATERIALS AND METHODS: There was one case of ossification of the posterior longitudinal ligament and one developmental multilevel stenosis that underwent laminectomy with lateral mass instrumentation. After surgery, the patients presented with quadriplegia; MRI demonstrated swelling of the spinal cord and intramedullary lesion in two cases. RESULTS: After surgery, the patients presented with quadriplegia; MRI demonstrated swelling of the spinal cord and intramedullary lesion in two cases. CONCLUSION: Although patients with such a medical condition are rare, it is difficult to predict postoperative swelling of the spinal cord before surgery. The surgeon should thus be aware of such rare disease conditions involving the spinal cord before the surgical procedure.

Cervical Cord Decompression Using Extended Anterior Cervical Foraminotomy Technique

OBJECTIVE: At present, gold-standard technique of cervical cord decompression is surgical decompression and fusion. But, many complications related cervical fusion have been reported. We adopted an extended anterior cervical foraminotomy (EACF) technique to decompress the anterolateral portion of cervical cord and report clinical results and effectiveness of this procedure. METHODS: Fifty-three patients were operated consecutively using EACF from 2008 to 2013. All of them were operated by a single surgeon via the unilateral approach. Twenty-two patients who exhibited radicular and/or myelopathic symptoms were enrolled in this study. All of them showed cervical cord compression in their preoperative magnetic resonance scan images. RESULTS: In surgical outcomes, 14 patients (64%) were classified as excellent and six (27%), as good. The mean difference of cervical cord anterior-posterior diameter after surgery was 0.92 mm (p<0.01) and transverse area was 9.77 mm2 (p<0.01). The dynamic radiological study showed that the average post-operative translation (retrolisthesis) was 0.36 mm and the disc height loss at the operated level was 0.81 mm. The change in the Cobb angle decreased to 3.46, and showed slight kyphosis. The average vertebral body resection rate was 11.47%. No procedure-related complications occurred. Only one patient who had two-level decompression needed anterior fusion at one level as a secondary surgery due to postoperative instability. CONCLUSIONS: Cervical cord decompression was successfully performed using EACF technique. This procedure will be an alternative surgical option for treating cord compressing lesions. Long-term follow-up and a further study in larger series will be needed.