Surgical challenges in the management of cervical kyphotic deformity in patients with severe osteoporosis: an illustrative case of a patient with Hajdu-Cheney syndrome.

PURPOSE: No standard strategy exists for the management of cervical kyphotic deformity in patients with severe osteoporosis. In fact, in such subpopulation, standard algorithms commonly used in patients with normal bone mineral density may not be applicable. In this Grand Rounds, the authors present a challenging case of a patient with Hajdu-Cheney syndrome, a rare disorder of bone metabolism induced by a Notch-2 mutation, who presented with cervical kyphotic deformity and severe osteoporosis. METHODS: A 65-year-old female patient with a previous diagnosis of Hajdu-Cheney syndrome presented with cervical myelopathy and cervical kyphotic deformity. The initial MRi demonstrated multilevel cervical canal stenosis. The CT-scan also revealed marked spondylolisthesis of C6 over C7 as well as numerous laminar and pedicle fractures, resulting in a cervical kyphosis of approximately 50 degrees. RESULTS: The patient was submitted to 360-degree decompression and fusion of the cervical spine consisting of a staged C6 anterior corpectomy and multilevel microdiscectomies with wide opening of the posterior longitudinal ligament in order to provide a satisfactory release of anterior spinal structures, followed by 24 h of cervical halo-traction, a second anterior approach for bone graft implantation in the site of the corpectomy as well as insertion of allografts and completion of the ACDF C2-T1 and plating, and, finally, a posterior C2-T3 pedicle screw instrumentation using intra-operative CT-scan (O-arm) navigation guidance. CONCLUSIONS: This case illustrates some intra-operative nuances as well as specific surgical recommendations for cervical deformity surgery in patients with severe osteoporosis, such as avoidance of Caspar pins for interbody distraction, use of intra-operative fluoroscopy for achievement of bicortical purchase of anterior cervical screws and placement of pedicle screws during posterior instrumentation. Moreover, such illustrative case demonstrates that, in the subpopulation of patients with severe osteoporosis, it may be possible to successfully apply cervical distraction after an isolated anterior approach with a satisfactory improvement in the cervical alignment, possibly avoiding more laborious 540-degree approaches such as the previously described back-front-back or front-back-front surgical algorithms.

Low-profile pelvic fixation with sacral alar-iliac screws.

BACKGROUND: In the last years, a new technique for pelvic fixation using 'sacral alar-iliac' screws has been proposed as an alternative to the classic 'iliac wing' screws and the old Galveston technique. METHODS: The authors provide a 'step-by-step' review of the technical details regarding this technique, as well as some important anatomical and radiological landmarks for its successful performance. CONCLUSIONS: 'Sacral alar-iliac' screws provide several advantages in relation to pelvic fixation with iliac bolts such as: better alignment with the rods, use of a 'low-profile' screw, and fixation of the sacroiliac (SI) joint, which avoids postoperative SI joint-related pain.

Sectioning of C2 nerve roots during C1-2 fusion: report of aberrant vertebral artery during C2 nerve root sectioning. Illustrative case.

BACKGROUND: Sectioning the C2 nerve root is increasingly utilized during posterior C1-2 fusion, as the nerve overlies the entry point for C1 lateral mass screws and the C1-2 joint. Nerve sectioning improves visualization for screw placement and enables joint decortication for arthrodesis. While rare, vascular injury is a devastating complication of atlantoaxial fusion. Anomalous vascular anatomy at C1-2 greatly increases risk of iatrogenic injury. OBSERVATIONS: A 78-year-old female with rheumatoid arthritis and prior C2-7 fusion presented with myelopathy from a compressive pannus at C1-2. She underwent C1 laminectomy and C1-2 posterior instrumented fusion. Intraoperatively, arterial bleeding occurred as the right C2 nerve root was sectioned. Vertebral artery injury was suspected, and tamponade was performed while vascular control was established. The artery passed aberrantly beneath the nerve root in the C1-2 foramen. It was repaired microsurgically, and patency was confirmed using indocyanine green. The remainder of the fusion was aborted. The patient wore a cervical collar and was treated with aspirin for 6 weeks before undergoing instrumented fusion. The patient suffered no deficits. LESSONS: Although rare, anomalous vertebral artery anatomy increases risk of injury at time of C2 nerve root sectioning. Preoperative assessment of the vasculature is vital.

Intracranial subarachnoid hemorrhage resulting from cervical spine dural arteriovenous fistulas: literature review and case presentation.

Cervical dural arteriovenous fistulas (dAVFs) are a rare cause of intracranial subarachnoid hemorrhage (SAH) but should be considered when other sources are not found. Subarachnoid hemorrhage caused by dAVF is thought to occur as a result of venous hypertension in most cases. The clinical presentation, acute onset of severe headache, is similar to that in patients with other causes of SAH; however, severe neurological deficits (Hunt and Hess Grade IV and V SAH) have not been reported in SAH caused by cervical dAVFs. Patients with this type of SAH commonly report suboccipital headache, neck pain, and nausea, and thus these hemorrhages can be easily dismissed as perimesencephalic SAH. Vigilant evaluation with 4-vessel cerebral angiography, including selective catheterization of both proximal vertebral arteries, should be performed. The practice of unilateral vertebral artery injection with reflux into the contralateral vertebral and posterior inferior cerebellar arteries has the potential to overlook cervical dAVF. Magnetic resonance imaging may be useful to evaluate for other causes of SAH but is probably not sensitive for the identification of a cervical dAVF. Surgical treatment of this lesion has an excellent outcome.

Biologic solutions for degenerative disk disease.

STUDY DESIGN: Literature review. OBJECTIVE: Review the potential use of biologic therapies for the treatment of degenerative disk disease. SUMMARY OF BACKGROUND DATA: Degeneration of the intervertebral disk is a common occurrence which, although asymptomatic in most instances, may result in axial skeletal pain, radiculopathy, and myelopathy. Significant progress has been made in understanding the pathophysiology of degenerative disk disease and as a result, new biologic therapies, including molecular, gene, and cell-based strategies, are being investigated to halt and reverse disk degeneration. RESULTS: Growth factors, inflammatory inhibitors, proteinase inhibitors, and intracellular regulatory proteins are among the molecular therapies that have been studied with encouraging results in both in vitro and in vivo experiments. However, the utility of these therapies in humans may be limited because of the limited therapeutic duration. Gene therapies have the potential to overcome the limited therapeutic duration of molecular treatments by transferring genes to the cells within the disk to encode for therapeutic proteins with potential long-term local production. Gene therapy for disk regeneration has been successful in a number of animal studies, but significant concerns exist with the safety of the many vectors used for gene transfer. Cell-based therapies, including reimplantation of nucleus pulposus cells expanded in culture and stem cell therapies, have also been studied extensively in animal models with good results. The EuroDisc clinical trial is currently underway in Europe exploring the reimplantation of disk cells that are removed at the time of diskectomy and expanded ex vivo. Mesenchymal stem cells, which are readily available without ethical concerns, are being studied extensively for disk regeneration. Mesenchymal stem cells can differentiate into a phenotype similar to native nucleus pulposus cells and have shown the potential for disk regeneration in animal studies. CONCLUSIONS: Biologic therapies for intervertebral disk regeneration have produced very encouraging results in both in vitro and in vivo studies. Despite successful experimental results, these therapies face a number of hurdles before acceptance for human use including safety concerns, efficacy in high-order animal and human studies, and issues with the role and timing of these treatments.

Evidence on magnetic resonance imaging of Brown-Séquard spinal cord injury suffered indirectly from a gunshot wound.

The authors describe a rare case of Brown-Séquard syndrome as a result of indirect, concussive trauma to the spinal cord from a gunshot wound (GSW) and present the magnetic resonance (MR) imaging evidence obtained in this interesting case. The patient was shot in the anterior neck and the bullet passed through the lateral aspect of the C-7 lateral mass and transverse process. Bone fragments from the lateral aspect of C-7 were displaced posteriorly into the soft tissues, but no abnormalities were noted within the spinal canal except for high-intensity signal on T2-weighted MR imaging within the right side of the spinal cord. This is the first reported case to provide MR imaging evidence of a Brown-Séquard spinal cord injury as a result of indirect trauma (concussive injury) from a GSW.

Comparison of fusion assessment techniques: computer-assisted versus manual measurements.

OBJECT: Fusion assessment after cervical arthrodesis can be subjective. Measures such as bridging bone quantification or extent of (limited) motion on dynamic studies are common but difficult to interpret and fraught with biases. We compared manual measurement and computer-assisted techniques in assessing fusion after anterior cervical discectomy and fusion (ACDF). METHODS: One hundred patients who underwent ACDF (512 intervertebral levels) were randomly selected for this radiographic review (follow-up 3-36 months). Two assessment techniques were performed by different observers, with each blinded to the results of the other. The manual spinous process displacement measurement technique was used to calculate motion between the spinous processes under magnification on a digital imaging workstation. Computer-assisted measurements of intervertebral angular motion were made using Quantitative Motion Analysis (QMA) software. Fusion criteria were arbitrarily set at 1 mm of motion for the manual technique and 1.5 degrees of angular motion for the QMA technique. RESULTS: The manual measurement technique revealed fusion in 61.7% (316 of 512) of the interspaces assessed, and QMA revealed fusion in 64.3% (329 of 512). These two assessment techniques agreed in 87.5% of cases, with a correlation coefficient of 0.68 between the two data sets. In cases in which the two techniques did not agree, QMA revealed fusion and the manual measurement revealed nonfusion in 64% of the disagreements; 98% of the disagreements occurred when motion was < 2 mm or 2 degrees. CONCLUSIONS: Although osseous fusion after arthrodesis remains difficult to assess, new computer-assisted techniques may remove the subjectivity generally associated with assessing fusion.

The cervical end of an occipitocervical fusion: a biomechanical evaluation of 3 constructs. Laboratory investigation.

OBJECT: Stabilization with rigid screw/rod fixation is the treatment of choice for craniocervical disorders requiring operative stabilization. The authors compare the relative immediate stiffness for occipital plate fixation in concordance with transarticular screw fixation (TASF), C-1 lateral mass and C-2 pars screw (C1L-C2P), and C-1 lateral mass and C-2 laminar screw (C1L-C2L) constructs, with and without a cross-link. METHODS: Ten intact human cadaveric spines (Oc-C4) were prepared and mounted in a 7-axis spine simulator. Each specimen was precycled and then tested in the intact state for flexion/extension, lateral bending, and axial rotation. Motion was tracked using the OptoTRAK 3D tracking system. The specimens were then destabilized and instrumented with an occipital plate and TASF. The spine was tested with and without the addition of a cross-link. The C1L-C2P and C1L-C2L constructs were similarly tested. RESULTS: All constructs demonstrated a significant increase in stiffness after instrumentation. The C1L-C2P construct was equivalent to the TASF in all moments. The C1L-C2L was significantly weaker than the C1L-C2P construct in all moments and significantly weaker than the TASF in lateral bending. The addition of a cross-link made no difference in the stiffness of any construct. CONCLUSIONS: All constructs provide significant immediate stability in the destabilized occipitocervical junction. Although the C1L-C2P construct performed best overall, the TASF was similar, and either one can be recommended. Decreased stiffness of the C1L-C2L construct might affect the success of clinical fusion. This construct should be reserved for cases in which anatomy precludes the use of the other two.

The utility of MRI in the evaluation of odontoid fractures.

STUDY DESIGN: Retrospective radiographic review. OBJECTIVE: The purpose of this study was to reassess the utility of magnetic resonance imaging (MRI) in the assessment of type II and shallow type III odontoid fractures. SUMMARY OF BACKGROUND DATA: The authors of previous studies have reported a 10% incidence of transverse atlantal ligament (TAL) injury with odontoid fractures and suggested that all odontoid fractures be evaluated preoperatively with MRI. METHODS: A retrospective radiographic review was performed on all odontoid fractures treated with anterior screw fixation from 1987 to 2006. Patients were not screened for TAL injury with MRI or dynamic radiographs before surgery. Each patient had dynamic studies using intraoperative fluoroscopy after screw placement. Evidence of TAL injury was also evaluated on follow-up radiographs by measuring the atlantodental interval (ADI) on neutral, flexion, and extension films. For the purpose of this study, an ADI>3 mm indicated possible TAL injury. Neutral follow-up radiographs were available for 77 patients (mean follow-up, 17.5 mo), and flexion/extension films were available for 34 patients (mean follow-up, 16.4 mo). The mean ADI of the patients with neutral films was 1.1 mm (range=0.5 to 2.1 mm). The mean ADI of the patients with flexion/extension films was 1.2 mm (range=0.6 to 1.8 mm) for flexion and 1.2 mm for extension (range=0.5 to 2.8 mm). There was no evidence of atlantoaxial instability to suggest TAL disruption. CONCLUSIONS: The results of our study demonstrate that the patients with type II and shallow type III odontoid fractures do not require MRI screening for TAL injury. We found no cases of patients with late instability to suggest that a TAL injury was missed.

Mortality rates in geriatric patients with spinal cord injuries.

OBJECT: The authors undertook this study to evaluate the incidence of spinal cord injury (SCI) in geriatric patients (> or = 70 years of age) and examine the impact of patient age, extent of neurological injury, and spinal level of injury on the mortality rate associated with traumatic SCI. METHODS: A prospectively maintained SCI database (3481 patients) at a single institution was retrospectively studied for the period from 1978 through 2005. Parameters analyzed included patient age, admission American Spinal Injury Association (ASIA) motor score, level of SCI, mechanism of injury, and mortality data. The data pertaining to the 412 patients 70 years of age and older were compared with those pertaining to the younger cohort using a chi-square analysis. RESULTS: Since 1980, the number of SCI-related hospital admissions per year have increased fivefold in geriatric patients and the percentage of geriatric patients within the SCI population has increased from 4.2 to 15.4%. In comparison with younger patients, geriatric patients were found to be less likely to have severe neurological deficits (greater percentage of ASIA Grades C and D injuries), but the mortality rates were higher in the older age group both for the period of hospitalization (27.7% compared with 3.2%, p < 0.001) and during 1-year follow-up. The mortality rates in this older population directly correlate with the severity of neurological injury (1-year mortality rate, ASIA Grade A 66%, Grade D 23%, p < 0.001). The mortality rate in elderly patients with SCI has not changed significantly over the last two decades, and the 1-year mortality rate was greater than 40% in all periods analyzed. CONCLUSIONS: Spinal cord injuries in older patients are becoming more prevalent. The mortality rate in this patient group is much greater than in younger patients and should be taken into account when aggressive interventions are considered and in counseling families regarding prognosis.

Odontoid synchondrosis fractures in children.

OBJECT: Odontoid synchondrosis fractures, although rare in the overall incidence of spinal trauma, are one of the more common fractures in young children. The goal of this study was to evaluate the demographic data, incidence of neurological deficits, treatment strategies, and outcomes in a combined series of odontoid synchondrosis fractures treated at the authors' institution and reported in other series. METHODS: In a retrospective chart review, the authors identified four odontoid synchondrosis fractures treated at their hospital since January 2000; these were combined with cases reported in six other series in the literature, yielding a total of 55 patients. Data regarding the patients' age, sex, delayed diagnosis, odontoid displacement, neurological deficits, treatment, and fusion status were collected. The patients' ages ranged from 9 months to 7 years (mean 2.8 years), with neither sex predominating. Diagnosis was delayed in eight cases. The orientation of the odontoid fracture was reported for 36 patients, with 94% experiencing anterior displacement. Spinal cord injury (SCI) was noted in 15 patients, including 11 with complete injuries and eight with SCI at the cervicothoracic junction. Forty-two (93%) of 45 patients with fractures initially treated with external immobilization attained fusion. Eight patients were treated with surgery; four initially, with no attempt at conservative therapy, three after failed halo immobilization, and one after nonunion because of delayed diagnosis. CONCLUSIONS: Odontoid synchondrosis fractures can be difficult to diagnose. In children younger than 7 years of age who present with neck pain or neurological deficits attributable to SCI, this fracture should be suspected. Given the high rate of fusion attained with conservative therapy, it is recommended for most synchondrosis fractures, although surgery may be warranted for individual cases.

Cervical spine deformity associated with resection of spinal cord tumors.

Postoperative sagittal-plane cervical spine deformities are a concern when laminectomy is performed for tumor resection in the spinal cord. These deformities appear to occur more commonly after resection of intramedullary spinal cord lesions, compared with laminectomy for stenosis caused by degenerative spinal conditions. Postlaminectomy deformities are most common in pediatric patients with an immature skeletal system, but are also more common in young adults (< 25 years of age) in comparison with older adults. The extent of laminectomy and facetectomy, number of laminae removed, location of laminectomy, preoperative loss of lordosis, and postoperative radiation therapy in the spine have all been reported to influence the risk of postlaminectomy spinal deformities. When these occur, patients should be monitored closely with serial imaging studies, because a significant percentage will have progressive deformities. These can range from focal kyphosis to more complicated swan-neck deformities. General indications for surgical intervention include progressive deformity, axial pain in the area, and neurological symptoms attributable to the deformity. Surgical options include anterior, posterior, and combined anterior-posterior procedures. The authors have reviewed the literature on postlaminectomy kyphosis as it relates to resection of cervical spinal cord tumors, and they summarize some general factors to consider when treating these patients.

Cholesteatoma of the clivus.

Cholesteatomas (central nervous system epidermoids) can be found intradurally or extradurally in the central nervous system. Extradural intraosseous lesions are most commonly found in the petrous bone. The authors describe a unique case of a clival cholesteatoma in a 64-year-old woman who presented with headaches. No other neurological complaints or physical examination findings were noted. Magnetic resonance imaging showed an expansile lesion centered in the middle portion of the clivus. A large portion of the clivus was eroded. The lesion was explored via a transnasal trans-sphenoidal approach and granular debris was evacuated. The cystic lining was stripped from the surrounding bone, and the bone opening was widely fenestrated. Pathological examination showed keratinous debris with macrophages and an outer lining of benign epithelial tissue consistent with a cholesteatoma (epidermoid cyst). When surgically accessible, these lesions should be excised to prevent a recurrence. If inaccessible, marsupialization may be considered.

The high incidence of tumor dissemination in myxopapillary ependymoma in pediatric patients. Report of five cases and review of the literature.

Myxopapillary ependymomas (MPEs) have historically been thought to be benign tumors occurring most frequently in adults. Only 8 to 20% of these tumors occur in the first two decades of life, making this tumor a rarity in pediatric neurosurgery. Five patients with intraspinal MPEs were treated by the authors between 1992 and 2003. Four (80%) of these five patients suffered from disseminated disease of the central nervous system (CNS) at the time of presentation; this incidence is much higher than that reported in the combined adult and pediatric literature. Combining five pediatric case series reported in the literature with the present series, the authors review a total of 26 cases of pediatric patients with intraspinal MPEs. In nine cases (35%) CNS metastases occurred. In those cases in which patients underwent screening for CNS tumor dissemination, however, the incidence of disseminated disease was 58% (seven of 12 patients). In pediatric patients MPEs may spread throughout the CNS via cerebrospinal fluid pathways; therefore, MR imaging of the entire CNS axis is recommended at both presentation and follow-up review to detect tumor dissemination.

Hemorrhage from moyamoya-like vessels associated with a cerebral arteriovenous malformation. Case report.

The authors describe a case of subarachnoid hemorrhage from moyamoya-like vessels associated with an arteriovenous malformation (AVM) in a 44-year-old Hispanic man who presented with severe headache. The AVM was located in the left parietal lobe and the ipsilateral middle cerebral artery was occluded. Although the patient was initially neurologically intact, he began to experience neurological deficits from mild vasospasm, illustrating the sensitivity of the underperfused portion of brain surrounding an AVM. His neurological deficits improved with aggressive hydration and elevated blood pressure. After a 3-week period, the AVM was resected without complication and all of the patient's neurological deficits resolved. The authors review radiographic findings of this unique case.

Lumbosacral ependymomas: a review of the management of intradural and extradural tumors.

OBJECT: The goal of this study was to review the management of intra- and extradural ependymomas. Spinal ependymomas most commonly occur as intramedullary tumors throughout the spinal axis. In the lumbosacral region, ependymomas are most commonly associated with the conus medullaris and cauda equina, but can also occur extradurally in the sacrum, presacral tissues, or subcutaneous tissues over the sacrum. These two tumor locations produce different management concerns. Intradural ependymomas, especially those in the lumbosacral region, are now recognized for their potential to spread throughout the central nervous system (CNS), whereas extradural tumors elicit more concern for their association with extraneural metastases. METHODS: The authors have reviewed the literature regarding both of these distinct tumors and have summarized recommendations for the management of intra- and extradural lumbosacral ependymomas. For both tumors, it appears that gross-total resection is the treatment of choice when feasible. The role of radiation therapy has not been adequately studied for either tumor location, but most clinicians use this modality in patients with subtotal resection of intradural ependymomas, local recurrence, or CNS dissemination. Data supporting the use of radiation therapy for extradural ependymomas are lacking. There does not appear to be a significant role for chemotherapy in either tumor location. CONCLUSIONS: Despite the risk for local recurrence and CNS dissemination, the prognosis for intradural lumbosacral ependymomas is good, with a greater than 90% 10-year patient survival in most series. The prognosis for extradural ependymomas does not appear to be as good. Much depends on extradural tumor location, however; the outlook is better for dorsal sacral tumors than presacral tumors.

Metastases to the pituitary gland.

Only 1% of all pituitary surgeries are performed to treat tumors that have metastasized to the pituitary gland; however, in certain cases of malignant neoplasms pituitary metastases do occur. Breast and lung cancers are the most common diseases that metastasize to the pituitary. Breast cancer metastasizes to the pituitary especially frequently, with reported rates ranging between 6 and 8% of cases. Most pituitary metastases are asymptomatic, with only 7% reported to be symptomatic. Diabetes insipidus, anterior pituitary dysfunction, visual field defects, headache/pain, and ophthalmoplegia are the most commonly reported symptoms. Diabetes insipidus is especially common in this population, occurring in between 29 and 71% of patients who experience symptoms. Differentiation of pituitary metastasis from other pituitary tumors based on neuroimaging alone can be difficult, although certain features, such as thickening of the pituitary stalk, invasion of the cavernous sinus, and sclerosis of the surrounding sella turcica, can indicate metastasis to the pituitary gland. Overall, neurohypophysial involvement seems to be most prevalent, but breast metastases appear to have an affinity for the adenohypophysis. Differentiating metastasis to the pituitary gland from bone metastasis to the skull base, which invades the sella turcica, can also be difficult. In metastasis to the pituitary gland, surrounding sclerosis in the sella turcica is usually minimal compared with metastasis to the skull base. Treatment for these tumors is often multimodal and includes surgery, radiation therapy, and chemotherapy. Tumor invasiveness can make resection difficult. Although surgical series have not shown any significant survival benefits given by tumor resection, the patient's quality of life may be improved. Survival among these patients is poor with mean survival rates reported to range between 6 and 22 months.

Spinal epidural lipomatosis: a review of its causes and recommendations for treatment.

Spinal epidural lipomatosis is most commonly observed in patients receiving long-term exogenous steroid therapy, but can also be seen in patients with endogenous steroid overproduction, obesity, or idiopathic disease. With this condition, there is hypertrophy of the epidural adipose tissue, causing a narrowing of the spinal canal and compression of neural structures. A majority of patients will present with progressive myelopathy, but radicular symptoms are also common. Conservative treatment--weaning from steroids or weight loss--can reverse the hypertrophy of the adipose tissue and relieve the neural compression. If conservative management fails, surgery with decompressive laminectomy is also very successful at improving the patient's neurological symptoms.

Combined S-1 and S-2 sacral alar-iliac screws as a salvage technique for pelvic fixation after pseudarthrosis and lumbosacropelvic instability: technical note.

Lumbosacropelvic pseudarthrosis after long spinal fusions for treatment of adult degenerative scoliosis remains a challenging condition. Moreover, although pelvic fixation with iliac screws is widely used in deformity surgery to provide a biomechanically strong distal anchor for long thoracolumbar constructs, there are very few options available after failed pelvic fixation with iliac screws. The authors conducted a retrospective review of the surgical charts and imaging findings of patients subjected to revision surgery for lumbosacropelvic pseudarthrosis from August 2011 to August 2012. This review identified 5 patients in whom a salvage technique combining both S-1 and S-2 sacral alar-iliac (SAI) screws had been performed. In this technical note, the authors present a detailed anatomical discussion and an appraisal of the sequential intraoperative steps of this new technique involving a combination of S-1 and S-2 SAI screws. The discussion is illustrated with a surgical case in which this technique was used to treat a patient with pseudarthrosis that had developed after fixation with classic iliac screws. In conclusion, although S-2 SAI screws have previously been reported as an interesting alternative to classic iliac wing screws, this report is the first on the use of combined S-1 and S-2 SAI screws for pelvic fixation as a salvage technique for lumbosacropelvic instability. According to the reported experience, this technique provides a biomechanically robust construct for definitive pelvic fixation during revision surgeries in the challenging scenarios of pseudarthrosis and instability of the lumbosacropelvic region.

Intramedullary neurenteric cyst associated with a tethered spinal cord: Case report and literature review.

BACKGROUND: Neurenteric cysts are benign tumors of the central nervous system (CNS) that represent 0.3% to 0.5% of all spinal cord tumors. They are usually extramedullary and found in the lower cervical and thoracic spine. Only 12.2% of neurenteric cysts are documented to be intramedullary. CASE DESCRIPTION: The authors report a case of a 35-year-old female that presented with progressive weakness and loss of coordination in her legs. Magnetic resonance imaging (MRI) showed an intramedullary cystic lesion in the thoracolumbar region and a low-lying conus medullaris suggesting tethered cord. The patient was taken to the operating room for detethering of her spinal cord and resection of the lesion. Pathologic examination of the tissue confirmed the diagnosis of a neurenteric cyst. CONCLUSION: A search of the literature since the advent of MRI showed 29 published cases of intramedullary neurentic cysts. Of the 24 published cases with a follow-up MRI, the average recurrence rate was 25% with a mean follow up of 51 months.