Clinicopathological considerations in patients with lumbosacral extraforaminal stenosis.

Lumbosacral extraforaminal stenosis is not uncommon among patients being treated for radicular symptoms. Patients who had lumbosacral extraforaminal stenosis were reviewed, and cadaver dissection was used to determine the anatomy of extraforaminal lesions. A total of 167 patients with lumbosacral spinal stenosis who underwent surgery from March 2004 to February 2006 were reviewed retrospectively. Among these, extraforaminal stenosis was observed in 26 patients (mean age 61.4 y; range 46-79). Leg pain and neurogenic claudication were common in patients with extraforaminal stenosis. One level was involved for 15 patients and 2 levels were involved for 11 patients. Complete decompression of the dorsal root ganglion or a root compressed by the fibrocartilagenous ligamentum flavum or a hypertrophied superior facet was performed. The mean follow-up was 8.3 months (range 6-26 months). The causes of extraforaminal stenosis were superior facet hypertrophy, especially hypertrophy of the superior lateral portion, or thickening of the ligamentum flavum, intertransverse ligament, or transforaminal ligament. T1-weighted, coronal MRI showed root impingement in the far-lateral zone. Postoperative outcomes were assessed using the Prolo scale; 13 patients demonstrated excellent outcomes, while 11 patients had good outcomes. No major complications or recurrences were observed during follow-up. Therefore, lumbosacral extraforaminal stenosis should be included in the differential diagnosis of lumbar radicular pain. A precise diagnosis using MRI is important, and complete decompression with an understanding of the extraforaminal anatomy is required.

Spinal instrumentation for interfacet locking injuries of the subaxial cervical spine.

A retrospective analysis of our surgical management of traumatic interfacet locking was performed. Eleven interfacet locking injuries were surgically treated. An anterior procedure was performed in five patients, posterior fixation in three and a combined procedure in three. Five facet locks were reduced by preoperative skull traction. After general anesthesia at surgery, another two cases were corrected manually. Surgical fixation using spinal instrumentation was performed. One patient treated with posterior fixation required an additional anterior procedure because of a delayed disc herniation. Spinal instrumentation avoided a halo vest. The anterior approach may be selected in patients who are reduced manually, while a combined procedure should be performed in patients with irreducible facet dislocation with disc herniation. Delayed symptomatic disc herniation may occur when only posterior fixation is performed.

Clinical and radiological analysis of ossification of the anterior longitudinal ligament causing dysphagia and hoarseness.

OBJECTIVE: We retrospectively analyzed the clinical and radiological characteristics of ossification of the anterior longitudinal ligament (OALL). METHODS: Seventeen patients with OALL who underwent surgery between 1995 and 2003 were reviewed. Symptomatic OALL was found in four patients. In 13 asymptomatic OALL patients who experienced mild to severe myelopathy, no swallowing difficulty was noted. The OALL was classified into three types by sagittal computed tomographic (CT) scans as segmental, continuous, and mixed and three types on axial CT scans as flat, nodular, and globular type. The thickness, numbers of involved vertebral bodies, and type and shape for symptomatic OALL were analyzed and compared with those for asymptomatic OALL. RESULTS: The mean thickness of 13.5 mm for symptomatic OALL was significantly higher than that of 6.5 mm for asymptomatic OALL (P = 0.0009). A globular shape on axial CT was common for symptomatic OALL. There were no differences in the numbers of involved vertebral bodies and types of OALL on sagittal CT scans. Surgical excision of OALL was performed for all cases of symptomatic OALL. In 7 of 13 asymptomatic cases, OALL was simultaneously removed during anterior decompressive surgery for the associated pathology. CONCLUSION: The thickness on axial CT scans was an important contributing factor to dysphagia and hoarseness as was the shape of the OALL. The type of OALL on sagittal CT scans was similar to that of ossification of the posterior longitudinal ligament but did not influence the development of dysphagia. Good relief from symptoms was achieved for symptomatic OALL after removal of OALL.

Clinical evaluation of traumatic central cord syndrome: emphasis on clinical significance of prevertebral hyperintensity, cord compression, and intramedullary high-signal intensity on magnetic resonance imaging.

BACKGROUND: We evaluated the prognostic and clinical value of radiological findings including prevertebral hyperintensity (HI), cord compression, intramedullary high-signal intensity (IMHSI) and instability in patients with traumatic central cord syndrome without evidence of fracture and dislocation. METHODS: The radiological and clinical findings of 23 patients who had undergone surgery between 1996 and 2002 were reviewed retrospectively. All of the patients underwent dynamic motion study and magnetic resonance (MR) imaging after trauma. Neurologic status was evaluated with American Spinal Injury Association motor score pre- and postoperatively and compared with the radiological findings. Anterior decompression and fusion were performed in 12 patients with 1- or 2-level lesions, and posterior decompression was done for 11 cases of multilevel lesions. RESULTS: Prevertebral HI was found in 17 patients. Among them, instability was revealed in 11 patients. There was significant correlation between prevertebral HI and instability (P = .014). Cord compression was found in varying degrees in all patients on MR imaging. Intramedullary high-signal intensity was found preoperatively in 19 (83%) of 23 patients, and it was revealed at the most compressed level of the spinal cord in all cases. The neurologic level was consistent with the level of instability (100%), IMHSI (95%), and cord compression (87%). Mean American Spinal Injury Association motor scores in patients with instability were lower than in those without instability (P < .05). CONCLUSIONS: The presence of prevertebral HI, IMHSI, and cord compression influenced the neurologic status of the patients. The instability was significantly associated with poor prognosis for neurologic outcome. Prevertebral HI on T2 MR imaging may be a possible indicator of instability in patients with central cord syndrome after hyperextension injury.

Surgery for dural ossification in association with cervical ossification of the posterior longitudinal ligament via an anterior approach.

STUDY DESIGN: Direct removal of an ossified mass via an anterior approach carries good decompression, to one- or two-level ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. Ossification occasionally involves not only the posterior longitudinal ligament (PLL) but also the underlying dura mater. Defect of the dura mater by resection of the dural ossification (DO) can cause cerebrospinal fluid leakage or neural injury. The technique of resection of OPLL with floating of DO provides satisfactory decompression and avoids dural defect or neural injury in OPLL associated with DO. METHODS: Four patients developed cervical myelopathy. Radiological examination revealed cord compression due to OPLL associated with DO. RESULTS: All patients underwent anterior procedures. After the necessary discectomies and corpectomies, OPLL was resected using a high-speed drill with a 4-mm steel burr and then with a 4-mm diamond burr. When the OPLL became paper-thin, it was separated from the dura mater using a microdissector and a Kerrison rongeur. There was a thin layer of the nonossified degenerated PLL between the residual OPLL and DO. Meticulous dissection of the residual OPLL over the DO was performed without removing the DO at this layer. Fixation was performed with a titanium cylindrical cage. CONCLUSION: This technical note describes the successful decompression of the spinal cord by removing OPLL only, and avoidance of dural defect or neural injury in cases of OPLL associated with DO.

Surgery for acute subaxial traumatic central cord syndrome without fracture or dislocation.

Twenty-two patients with subaxial acute traumatic central cord syndrome (CCS) without fracture or dislocation who underwent surgery between 1995 and 2002 were reviewed, retrospectively. There were 13 males and nine females ranging in age from 24 to 84 years (mean 61.2). Falls were the most common injury (68%), followed by motor vehicle accidents (32%). All patients had dynamic cervical lateral radiographs and magnetic resonance imaging (MRI). Cord compression was present in all cases and cervical instability in 11. Associated pathology included disc herniation in seven patients, cervical spondylosis (CS) in 11 and ossification of the posterior longitudinal ligament (OPLL) in four. Anterior decompression and fusion was performed in 12 patients with 1- or 2-level lesions. Posterior decompression and fusion was performed for multilevel lesions in 11 patients, including one patient who required re-operation. The interval between injury and surgery ranged from 1 to 37 days (mean 8.0). Postoperatively, all patients improved clinically. We conclude that surgical management of subaxial acute traumatic CCS without fracture or dislocation improved neurological status and prevented delayed neurological deterioration in our patients.

Dural ossification associated with cervical ossification of the posterior longitudinal ligament: frequency of dural ossification and comparison of neuroimaging modalities in ability to identify the disease.

OBJECT: The authors' goal in this study was to understand the frequency and pattern of dural ossification (DO, and to evaluate the effectiveness of neuroimaging modalities used to identify this disease in association with ossification of the posterior longitudinal ligament (OPLL). METHODS: One hundred eleven patients with OPLL underwent anterior procedures. Of these patients, 17 (15.3%) had associated ossification of the dura mater. There were 10 cases of DO in the 94 patients with segmental OPLL and seven in the 17 patients with nonsegmental OPLL (seven continuous and 10 mixed-type OPLL). Retrospective evaluation of DO was performed by examining plain x-ray films, polytomography studies, computerized tomography (CT) scans, and magnetic resonance (MR) images. A positive correlation was found between the type of OPLL and the frequency of DO (p < 0.01). The DO was classified into the following three types according to shape: 1) isolated type, 2) double-layer type, and 3) en bloc type, based on its relationship with OPLL. There were 10 lesions of the double-layer type, four en bloc type, and three isolated type; the double-layer pattern of DO was the most common. All DOs as well as OPLLs (17 cases) were identified using bone-window CT scanning. Polytomography was used successfully to identify all 12 OPLLs, whereas DO was recognized in seven of the 12 cases. Magnetic resonance imaging could not identify DO (none of the 17 cases), although OPLL was identified on MR imaging in 12 of the 17 cases. CONCLUSIONS: Three patterns of DO associated with OPLL, that is, isolated, double-layer, and en bloc types, were confirmed by retrospective analysis of neuroimaging findings. Nonsegmental OPLL was likely to be accompanied by DO. Bone-window CT scanning was most useful for identification of DO as well as OPLL, whereas MR imaging was ineffective in recognizing DO.

Traumatic C6-7 subluxation associated with C-7 fracture treated with a pedicle screw system under navigation guidance--case report.

A 51-year-old female presented with traumatic C6-7 subluxation associated with C-7 fracture due to an automobile accident. She underwent pedicle screw fixation at C-6, C-7, and T-1 for stabilization of the spinal column. A neuronavigation system was used to obtain accurate placement of the pedicle screws. The patient recovered well without further neurological compromise. Postoperative cervical radiography showed reasonable restoration of the vertebral column without delayed kyphotic deformity.