Myelopathy associated with instability consequent to resection of ossification of anterior longitudinal ligament in DISH.

PURPOSE: The presence of prominent OALL (ossification of anterior longitudinal ligament) in the anterior cervical spine has been implicated as a cause of dysphagia. Surgical resection of the OALL is considered effective for the management of diffuse idiopathic skeletal hyperostosis (DISH)-related dysphagia. Although many reports have been published on DISH-related dysphagia, no cases of postoperative cervical instability have been reported thus far. We present a case in which the patient developed myelopathy associated with instability consequent to resection of OALL in DISH. METHODS: A 62-year-old man presented with progressive dysphagia that persisted for a year. The patient's symptoms were successfully resolved by resection of OALL. Five years after the surgery, the dysphagia resurfaced and was found to be caused by the regrowth of the OALL. A repeat surgery was performed, and the dysphagia disappeared. Eleven months after the second surgery, he visited the hospital with progressive quadriparesis and pain in the cervical region. RESULTS: Nine-month follow-up radiologic study revealed cervical instability at the level of C5-6 resulting in myelopathy. The patient underwent decompressive laminectomy and posterior fusion surgery. CONCLUSION: Surgical resection of DISH-related dysphagia typically yields excellent outcomes, but our experience in this case highlights the possibility of OALL regrowth and subsequent cervical instability after resection of OALL.

Recurrent esophageal perforation after anterior cervical spine surgery: case report.

PURPOSE: Delayed esophageal perforation after anterior cervical discectomy and fusion (ACDF) is an extremely rare cause of infection such as spondylodiscitis. We present a rare case in which a patient had two delayed esophageal perforations occurring 20 and 25 years after ACDF. By sharing our experience of this rare case, we hope to provide new information related to delayed esophageal perforation. METHODS: We present the case of a 72-year-old patient who underwent ACDF due to cervical spondylosis 25 years ago. Delayed esophageal perforation occurred 20 years postoperatively and healed spontaneously with conservative treatment. RESULTS: Five years later, a second esophageal perforation occurred, which required surgical intervention and involved recurrent infection. CONCLUSIONS: We suggest that it is important to consider follow-up in patients with spontaneously healed esophageal perforations. Furthermore, any patient with symptoms subsequent to a spontaneously healed esophageal perforation, even after an interval of several years, should receive a thorough evaluation for possible recurrent esophageal perforation.

Long-term recurrence rates after the removal of spinal meningiomas in relation to Simpson grades.

PURPOSE: Simpson grade II removal (coagulation of the dural attachment after gross total removal) of spinal meningioma is considered an acceptable alternative, but increased recurrence after more than 10 years has been reported. More attention must be paid to the long-term surgical outcomes after Simpson grade II removal. METHODS: A retrospective review was performed for 20 patients (M:F = 5:15; age, 59 ± 9 years) with Simpson grade II removal (mean follow-up period, 12.9 years; range 10.0-17.5). Magnetic resonance (MR) imaging was conducted in 17 patients at 88 ± 52 months (range 12-157). During the same period, Simpson grade I removal (removal of the dural origin) was performed in 21 patients (follow-up, 89 ± 87 months; range 9-316). Radiological recurrence was defined as a visible tumor on a follow-up MR image, and clinical tumor recurrence was defined as the recurrence of symptoms. RESULTS: At the final follow-up, neurological symptoms had improved in 16/20 patients and remained stable in 4/20. A recurrent tumor was detected in one patient due to increased back pain at 92 months postoperative, but the symptom was stable without surgery until the last follow-up (124 months). The radiological and clinical recurrence-free survival periods were 150 ± 7 months (95 % CI 136-163) and 204 ± 6 months (95 % CI 193-215), respectively. There was no recurrence after Simpson grade I removal, whereas neurological deterioration occurred in two patients after surgery. CONCLUSIONS: Simpson grade II removal may be an alternative option if the risk of complications with Simpson grade I removal is expected to be high.

Minimally invasive cervical foraminotomy and diskectomy for laterally located soft disk herniation.

PURPOSE: The posterior cervical foraminotomy and diskectomy (PCD) is a traditional surgical technique for patients with laterally located soft-disk herniation. Recently, tubular retractor-assisted posterior foraminotomy and diskectomy (MTPF) and posterior percutaneous endoscopic cervical foraminotomy and diskectomy (P-PECD) have been introduced, but a comparative study has not yet been performed. METHODS: Patients with foraminal soft-disk herniation and a follow-up period of >2 years were retrospectively reviewed; 22 patients underwent a MTPF and 22 patients underwent a P-PECD. The primary end-point was an improvement of arm pain more than 4.3. The clinical parameters (age, sex, disability index, neck and arm pain), radiological parameters (cervical curvature, segmental angle, anterior-/posterior-disk height and amount of facet joint removal) preoperatively and at postoperative month 24 and the surgical methods were considered as co-variates. RESULTS: Successful outcome was achieved in 19/22 (87%) of the patients after both MTPF and a P-PECD. Preoperative SA showed trend (P = 0.08; OR 1.2; 95% CI 0.98-1.4) and the cut-off SA was 1.45° (sensitivity 80%, specificity 73%). The length of the facet joint's removal was 0.02-2.49 mm (0.1-15.2%) with no difference between the MTPF and P-PECD. The surgical method was not a significant factor. CONCLUSIONS: For patients with foraminal soft-disk herniation, either MTPF or P-PECD, may be regarded as an alternative options to open surgery. Preoperative kyphotic SA (cut-off value 1.45°) seemed to be associated with poor outcome and this may be considered in selecting surgical methods.

Preoperative Risk Factors for Recurrent Lumbar Disk Herniation in L5-S1.

BACKGROUND CONTEXT: Although numerous studies have reported on recurrent lumbar disk herniation (rLDH), few have reported on recurrence of L5-S1 level. PURPOSE: We investigated whether the preoperative risk factors, such as disk degeneration, disk height, sagittal range of motion (sROM), width of L5 vertebral transverse process, and iliac crest height, have any effect on rLDH in L5-S1. STUDY DESIGN: A retrospective case control study. PATIENT SAMPLE: A total of 467 patients were enrolled in this study. OUTCOME MEASURES: The disk degeneration, disk height, sROM, width of L5 vertebral transverse process, and iliac crest height were calculated using magnetic resonance imaging and simple radiography. MATERIALS AND METHODS: We compared the clinical parameters (age, sex, body mass index, symptom duration, diabetes, smoking, preoperative visual analogue scale, herniation type, annular defect size) and preoperative radiologic parameters [disk degeneration, disk height, sROM, relative width of L5 vertebral transverse process (RT), iliac crest height index (IHI)] of recurrent and nonrecurrent groups. RESULTS: Patient with rLDH had its onset 39.4±17.9 months (7-90 mo) after primary surgery. Of the 39 rLDH cases, herniation was ipsilateral to previous LDH in 29 patients and contralateral in 10. Multiple logistic regression analysis showed that moderate disk degeneration with preserved height (group B), a large sROM, a small RT, a low IHI, and being male were significant risk factors for rLDH. CONCLUSIONS: Moderate disk degeneration, a large sROM, a small RT, and a low IHI are biomechanical risk factors of rLDH in L5-S1. The results also suggested being male and having a large annular defect increase recurrence after discectomy, especially in cases of ipsilateral rLDH.

Intramedullary spinal cord metastasis in renal cell carcinoma: a case report of the surgical experience.

Intramedullary spinal cord metastasis (ISCM) from renal cell carcinoma (RCC) is rare manifestation and most of them are treated by adjuvant treatment modalities like radiotherapy. Despite the radio-resistance of RCC itself, focal radiotherapy has been preferred as the first-line treatment modality of ISCM from RCC and only a few cases underwent surgical treatment. We describe a case of ISCM from RCC, which underwent surgical excision and pathologically confirmed. A 44-yr-old man was presented with rapid deterioration of motor weakness during focal radiotherapy for ISCM from RCC. After the surgery for removal of the tumor mass and spinal cord decompression, his motor power was dramatically improved to ambulate by himself. We report the first published Korean case of ISCM from RCC confirmed pathologically and describe our surgical experience and his clinical characteristics.

A synergistic bone sparing effect of curcumin and alendronate in ovariectomized rat.

BACKGROUND: The purpose of this study was to evaluate the therapeutic effects of combination therapy with curcumin and alendronate on bone remodeling after ovariectomy in rats. METHODS: Eighty female Sprague-Dawley rats underwent either a sham operation (the sham group) or bilateral ovariectomy (OVX). The ovariectomized animals were randomly distributed amongst four groups: untreated OVX group, curcumin-administered group, alendronate-administered group, and the combination therapy group. At 8 and 12 weeks after surgery, rats from each of the groups were euthanized. Serum biochemical markers of bone turnover, including osteocalcin and alkaline phosphatase (ALP), and the telopeptide fragment of type I collagen C-terminus (CTX) were analyzed. Bone histomorphometric parameters of the 4th lumbar vertebrae were determined by micro-computed tomography (CT). In addition, mechanical strength was determined by a three-point bending test. RESULTS: Serum biochemical markers of bone turnover in the experiment groups (curcumin administered group, alendronate administered group, and the combination therapy group) were significantly lower than in the untreated OVX group (p < 0.05). The combination therapy group had lower ALP and CTX-1 concentrations at 12 weeks, which were statistically significant compared with the curcumin only and the alendronate only group (p < 0.05). The combination therapy group had a significant increase in BMD at 8 weeks and Cr.BMD at 12 weeks compared with the curcumin-only group (p = 0.005 and p = 0.013, respectively). The three point bending test showed that the 4th lumbar vertebrae of the combination therapy group had a significantly greater maximal load value compared to that of the curcumin only and the alendronate only group (p < 0.05). CONCLUSIONS: The present study demonstrated that combination therapy with a high dose of curcumin and a standard dose of alendronate has therapeutic advantages over curcumin or alendronate monotherapy, in terms of the synergistic antiresorptive effect on bone remodeling, and improving bone mechanical strength.

Vertebral artery injury in destabilized midcervical spine trauma; predisposing factors and proposed mechanism.

BACKGROUND: By now it has been well established that vertebral artery injury (VAI) is associated with unstable cervical spine injuries resulting from blunt trauma. A more complete understanding of predisposing factors and the mechanism of injury in VAI should result in improved outcomes and reduced risk for patients with VAI associated with unstable cervical spine injury following blunt trauma. The authors report statistical outcome and hypothesis to more thoroughly examine the predisposing factors for VAI, of which management is controversial, in destabilized midcervical spine trauma. METHODS: Ninety-one of 131 consecutive patients who underwent surgery for a traumatically destabilized subaxial cervical spine were included, and results were analyzed statistically by logistic regression. RESULTS: Eighteen patients (19.8 % of 91 patients) had a VAI associated with midcervical spine trauma (C2-C6). In univariate statistical analysis, transverse foramen fracture (P = 0.002), facet dislocation (P = 0.014), and facet fracture (P = 0.001) were significant risk factors. However, only facet fracture was determined to be significant risk factor after multivariate analysis (P = 0.006, odds ratio 20.98). It is hypothesized that a VAI occurs in a midcervical spine injury when a facet fracture allows the bony compartment to impinge on the relatively narrow free space of the intervertebral foramen, which is also occupied by the cervical root. CONCLUSION: A facet fracture is the most important risk factor for VAI in patients with a destabilized midcervical spine injury. Patients with a C2-C6 facet fracture may require a definitive evaluation with vertebral artery imaging.

Timely assessment of infarct volume and brain atrophy in acute hemispheric infarction for early surgical decompression: strict cutoff criteria with high specificity.

PURPOSE: For a large hemispheric infarction, the clinical decision for decompressive surgery is commonly made on the basis of both radiological data showing brain swelling with herniation and concomitant neurological deterioration. However, for early decompressive surgery before clinical deterioration, strict cutoff criteria with a high specificity are required on the basis of timely assessment of the infarct volume. MATERIALS AND METHODS: Sixty-one patients who presented with a hemispheric infarction were initially evaluated using diffusion-weighted images (DWIs) within 14 h and computed tomography (CT) scans 24 ± 4 h after stroke onset to assess the infarct volume and midline shift. In addition, brain atrophy was evaluated using the bicaudate ratio. Twenty-one patients developed a malignant course, while 40 patients experienced a non-malignant course. RESULTS: According to a receiver-operating characteristic curve analysis for 50 patients with a bicaudate ratio <0.16, an initial infarct volume >160 ml in the DWI achieved a 97% specificity and 76% sensitivity, while an initial infarct volume >135 ml achieved an 86% specificity and 91% sensitivity. For the follow-up CT scans, an infarcted lesion volume >220 ml and midline shift >3.7 mm provided a 100% and 98% specificity, respectively. CONCLUSIONS: For the patients who presented with an acute hemispheric infarction and had a bicaudate ratio <0.16, an initial infarct volume >160 ml in a DWI within 14 h after stroke onset is highly predictive of a malignant course. In addition, an infarct volume >220 ml or midline shift >3.7 mm in the follow-up CT approximately 24 h after stroke onset facilitates early surgical decompression before clinical deterioration.

Retrospective report of symptomatic postoperative discal pseudocyst after lumbar discectomy.

BACKGROUND: Rarely, a symptomatic discal pseudocyst can develop after discectomy. Only very recently one clinical article and one case report about this type of pseudocyst were published: Kang and Park (J Korean Neurosurg Soc 49(1):31-36, 2011); Young PM, Fenton DS, Czervionke LF (Spine J. 9(2):e9-e15, 2009). Here, in an attempt to more clearly discriminate this peculiar cyst, the authors retrospectively report the clinical, radiological, and histological findings in 12 symptomatic patients with cystic lesions attached to an operated disc. METHODS: From January 2007 to May 2010, 12 patients who experienced recurrent symptoms after successful lumbar discectomy were diagnosed with postoperative discal pseudocyst (PDP). After discectomy, the mean time to relapsing radiculopathy was 23.3 days (range, 9-38 days) with a mean of 6.8 ± 1.3 on the visual analogue scale (VAS). PDPs were detected on magnetic resonance imaging (MRI) at 31.2 days (range, 14-60 days) after the initial surgery. Of these 12 patients, 6 were treated conservatively (group C) and 6 by surgery (group S). RESULTS: In the six patients in group C, the mean duration of relapsing pain was 77.8 days (range, 20-225 days), and near total or total regression of the cyst was detected at a mean of 82.7 days (range, 23-240 days) after initial detection by MRI. Time to spontaneous regression of PDP varied widely. In the six patients in group S, surgical treatment was administered within a few days of MRI diagnosis and achieved successful pain relief. CONCLUSIONS: Postoperative discal pseudocyst appears to develop after lumbar discectomy and can regress spontaneously.

Feasibility of C2 translaminar screw as an alternative or salvage of C2 pedicle screws in atlantoaxial instability.

STUDY DESIGN: A retrospective outcome study. OBJECTIVE: The purpose of this study was to analyze the clinical outcomes of our experience with the C2 translaminar screw technique and evaluate its feasibility as an alternative or salvage of the pedicle screw. SUMMARY OF BACKGROUND DATA: Pedicle screws are the most biomechanically stable screws for use in atlantoaxial fixation. However, in cases with elevated risk of neurovascular complications or failure of screw insertion attempts, a reliable alternative technique is required. METHODS: Fourteen patients with atlantoaxial instability underwent posterior fixation with C2 translaminar screws. Indications included traumatic instability, atlantoaxial subluxation, os odontoideum, and fusion failure after anterior fixation of a type II odontoid process fracture. A total of 26 screws were inserted and all patients were assessed both clinically and radiographically. RESULTS: No procedure-related complications or hardware failures were observed during the follow-up. Postoperative computed tomographic scans revealed laminar breach in 3 patients and none of these resulted in neurological symptoms. Radiographically demonstrated bony fusion was established in 11 patients (91.7%) at follow-up over 6 months, and 5 patients with initial neurological deficit demonstrated at least 1 grade improvement by Frankel grade. CONCLUSIONS: C2 translaminar screws provide surgeons with an expanded option for posterior fusion in high cervical lesions. This technique is safe and easy to adopt with a favorable rate of successful fusion. We believe that preoperative planning using computed tomographic scan is mandatory and use of an additional connector may reduce the stress and strain of the screws.

The retrogasserian zone versus dorsal root entry zone: comparison of two targeting techniques of gamma knife radiosurgery for trigeminal neuralgia.

BACKGROUND: We performed a comparative study of the retrogasserian zone (RGZ) with the dorsal root entry zone (DREZ) target to determine effective gamma knife radiosurgery (GKRS) technique in patients with medically refractory trigeminal neuralgia (TN). METHODS: We retrospectively reviewed the records of 39 patients with refractory TN undergoing GKRS between April 2005 and October 2008. Until October 2007, DREZ was used as the primary target point. Since November 2007, RGZ has been targeted, located anterior to DREZ. The pain outcome of patient, pain recurrence, and treatment-related complications were evaluated. FINDINGS: Using the Barrow Neurologic Index (BNI) pain score, 15 (93.8%) RGZ and 20 (87.0%) DREZ cases achieved treatment success (BNI pain score I-IIIb) (p = 0.631). Seven (43.8%) RGZ and four (17.4%) DREZ patients reported complete pain relief without medications (BNI pain score I). The time to a response after the GKRS was significantly shorter in the RGZ group (mean 4.1 weeks) than in the DREZ group (mean 6.4 weeks) (p = 0.044). The total complication rate (25.0%) in the RGZ group was similar to the DREZ group (26.1%); however, frequency of bothersome facial numbness and dry eye syndrome was lower in the RGZ group (0%, 0%) compared to the DREZ group (13.1%, 8.7%) (p = 0.255 and 0.503). CONCLUSIONS: The RGZ targeting technique in the GKRS for TN had a better treatment success, with fewer bothersome complications compared to the DREZ target.

The Effect of an Educational and Interactive Informed Consent Process on Patients With Cervical Spondylotic Myelopathy Caused by Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: Prospective observational cohort study. OBJECTIVE: In this study, an educational and interactive informed consent (EIC) program was proposed for patients with cervical spondylotic myelopathy caused by ossification of the posterior longitudinal ligament (OPLL-CSM) to improve their comprehension level during the informed consent process. SUMMARY OF BACKGROUND DATA: OPLL-CSM is a slow progressive disease, and it is difficult for patients to understand the disease. Few studies have evaluated very specific programs to improve the informed consent process for these patients. METHODS: This prospective study evaluated patients with OPLL-CSM who either underwent the proposed EIC process (n = 63) or the standard consent process (n = 124). The standard consent process only included a physician-patient interview. During the EIC process, information was provided regarding OPLL-CSM through information booklets, a video, verbal information, and initial and second physician-patient interviews. After the second physician-patient interview, the patient was requested to answer 14 medical questions to assess their knowledge about OPLL-CSM. The proposed EIC process took approximately 90 minutes. They were asked to report the most useful educational method and the most effective method of reinforcing verbal communication. RESULTS: The mean questionnaire scores were higher in the EIC group than in the control group (P < 0.001). Video was selected by 50/63 patients (79.4%) as the most useful EIC process method, and the most effective method of reinforcing verbal communication was video (n = 61; 96.8%). Patients in the EIC group reported having higher satisfaction with surgery (P = 0.024) than did those in the control group. CONCLUSION: The proposed EIC process was shown to result in good patient comprehension and recall regarding OPLL-CSM. Using a video was the most informative and effective reinforcement of verbal communication. The enhanced educational group had better knowledge and improved satisfaction following surgery. The EIC process might help physicians educate and counsel patients regarding OPLL-CSM and its treatment. LEVEL OF EVIDENCE: 2.

Unilateral lateral mass-facet fractures with rotational instability: new classification and a review of 39 cases treated conservatively and with single segment anterior fusion.

OBJECTIVE: This study examined the clinical and radiologic results of cervical spine injuries associated with a unilateral lateral mass-facet fracture (ULMFF) in an attempt to clarify the fracture pattern and treatment strategies using single-level anterior fusion. METHODS: From July 2003 to June 2006, adult patients, who had sustained ULMFFs of the middle cervical spine, were reviewed retrospectively. The fractures were classified into six subtypes using roentgenogram and computed tomography imaging with three-dimensional analysis. Initially, 15 patients without severe translation and kyphosis were treated with external immobilization and 24 patients were treated surgically with anterior fusion. The fusion state and spinal alignment were evaluated at the follow-up visits. RESULTS: Thirty-nine patients had 27 lateral mass fractures and 14 facet joint fractures. The lateral mass fractures were divided into the following four subtypes: unilateral spondylolithesis in 16, separation fracture in 5, comminution type in 4, and split type in 2. Facet fractures with/without facet dislocation were observed in seven patients. Twelve patients who received conservative management required delayed fusion due to persistent pain and late instability. Overall, 36 patients, with the exception of three cases with a successful result by external immobilization, underwent surgery using single-level anterior fixation with anterior plating. A poor radiologic outcome was observed in eight patients after the procedure. Five cases showed incomplete reduction or a failure of the reduction. Three cases had adjacent instability and malalignment despite the early fusion observed due to short-segment fusion in the separation type. CONCLUSION: This retrospective review of ULMFF showed that nonsurgical treatment is usually unsuccessful, and early single-level anterior arthrodesis has a favorable outcome. However, exclusive two-level stabilization or pedicle screw fixation needs to be considered in the separation type.

Palliative surgery for metastatic thoracic and lumbar tumors using posterolateral transpedicular approach with posterior instrumentation.

BACKGROUND: The purpose of this study was to evaluate the clinical outcomes of patients with metastatic thoracic and lumbar tumors after palliative surgery using PTA with posterior instrumentation. METHODS: Twenty-one consecutive patients with metastatic thoracic and lumbar spine tumors were treated using a PTA with posterior instrumentation. The patient group is composed of 14 men and 7 women with mean age of 56.6 years (range, 32-76 years). The average extent of vertebral involvement was 2.2 segments. RESULTS: The mean operative time was 3.1 hours (range, 2-4.5 hours), and the mean blood loss was 1400 mL (range, 600-2500 mL). All patients with pain showed improved or similar pain levels after surgery, and Frankel grades were decreased significantly by operation. Postoperative mean survival was 8.9 months and ranged from 2 to 36 months. There were 4 (26.7%) patients who died at less than 3 months after surgery and 3 patients (14%) who required a repeat operation. Of 5 patients treated using a PTA despite a Tomita's prognostic score of more than 8, 3 patients (with preoperative ECOG grade IV) died within 6 weeks postoperatively, and the other 2 patients (with preoperative ECOG grade III) survived longer than 10 weeks (1 patient survived for 10 weeks, and the other for 12 weeks). CONCLUSION: The PTA with posterior instrumentation for metastatic thoracic and lumbar spinal tumors achieved good surgical results. Palliative surgery for patients with a Tomita's prognostic score of more than 8 may be considered in selected cases, especially in those with ECOG grade III.

Risk factors for cage migration and cage retropulsion following transforaminal lumbar interbody fusion.

BACKGROUND CONTEXT: Transforaminal lumbar interbody fusion (TLIF) is a widely accepted surgical procedure, but cage migration (CM) and cage retropulsion (CR) are associated with poor outcomes. PURPOSE: This study seeks to identify risk factors associated with these serious events. STUDY DESIGN: A prospective observational longitudinal study. PATIENT SAMPLE: Over a 5-year period, 881 lumbar levels in 784 patients were treated using TLIF at three spinal surgery centers. OUTCOME MEASURES: We evaluated the odds ratio of the risk factors for CM with and without subsidence and CR in multivariate analysis. METHODS: Our study classified CM into two subgroups: CM without subsidence and CM with subsidence. Cases of spinal canal and/or foramen intrusion of the cage was defined separately as CR. Patient records, operative notes, and radiographs were analyzed for factors potentially related to CM with subsidence, CM without subsidence, and CR. RESULTS: Of 881 lumbar levels treated with TLIFs, CM without subsidence was observed in 20 (2.3%) and CM with subsidence was observed in 36 (4.1%) patients. Among the CM cases, CR was observed in 17 (17/56, 30.4%). The risk factors of CM without subsidence were osteoporosis (OR 8.73, p < .001) and use of a unilateral single cage (OR 3.57, p < .001). Osteoporosis (OR 5.77, p < .001) and endplate injury (OR 26.87, p < .001) were found to be significant risk factors for CM with subsidence. Risk factors of CR were osteoporosis (OR 7.86, p < .001), pear-shaped disc (OR 8.28, p = .001), endplate injury (OR 18.70, p < .001), unilateral single cage use (OR 4.40, p = .03), and posterior cage position (OR 6.45, p = .04). A difference in overall fusion rates was identified, with a rate of 97.1% (801 of 825) for no CM, 55.0% (11 of 20) for CM without subsidence, 41.7% (15 of 36) for CM with subsidence, and 17.6% (3 of 17) for CR at 1.5 years postoperatively. CONCLUSIONS: Our results suggest that osteoporosis is a significant risk factor for both CM and CR. In addition, a pear-shaped disc, posterior positioning of the cage, the presence of endplate injury and the use of a single cage were correlated with the CM with and without subsidence and CR.

Catastrophic intramedullary hematoma following Kümmell's disease with large intravertebral cleft.

BACKGROUND CONTEXT: Kümmell's disease is defined as avascular osteonecrosis and occurs after delayed posttraumatic vertebral collapse. Devastating cord injury with Kümmell's disease is rare except in advanced cases with kyphosis and posterior cortex breakage. PURPOSE: The authors report unique experience with patients who presented with a catastrophic intramedullary hematoma after early stage Kümmell's disease without kyphosis. STUDY DESIGN: Case report with analysis of the literature. METHODS: A 72-year-old woman with osteoporotic vertebral fractures of T12 visited the emergency room complaining of persistent back pain and paraparesis. The plain radiographic examination revealed mild osteoporotic wedge compression fractures. The magnetic resonance images revealed the fracture cavity as a discrete area of abnormal low and high signal, which is consistent with vertebral osteonecrosis with evidence of Kümmell's disease on T12, and conus showing an extensive hematoma with mixed signal changes. RESULTS: The authors performed laminectomy and the removal of the intramedullary hematoma, followed by vertebroplasty on T12. The spinal column was reduced and fixed posteriorly with a pedicle screw system using a one-stage procedure. CONCLUSIONS: An increasing awareness of the delayed vertebral collapse with cord injury attached to an osteoporotic spine fracture, as well as a periodic follow-up and treatment are essential for preventing catastrophic neurological impairment.

Anterior cervical stabilization using a semi-constrained cervical plate and titanium mesh cage for single level corpectomy.

In this study we reviewed the treatment outcomes for 20 consecutive patients who underwent anterior 1-level cervical corpectomy and reconstruction using a titanium mesh cage and semi-constrained plating after an average follow-up of 14.8 months. Two groups, each of 10 patients, underwent surgery with 10-mm and 13-mm diameter cages, respectively. Bony fusion and the radiological outcome were evaluated using follow-up radiography and sagittal reconstructed CT scans. The radiographs revealed bony consolidation in 95% of the 20 patients during follow-up. Five cases of construct failure occurred after surgery:1 failure (10%) was encountered in the 10-mm cage group and 4 (40%) occurred in the 13-mm cage group (P=0.085). The failures were mainly the result of cage settling and screw-plate failure. Although the clinical outcomes and fusion rates for anterior cervical stabilization using a semi-constrained plate and titanium cage were favorable, further biomechanical evaluations and a prospective randomized study will be necessary to fully understand this dependence of implant failure on cage size.

Safe Margin beyond Dens Tips to Ventral Dura in Anterior Odontoid Screw Fixation : Analysis of Three-Dimensional Computed Tomography Scan of Odontoid Process.

OBJECTIVE: Anterior odontoid screw fixation is a safe and effective method for the treatment of odontoid fractures. The surgical technique is recommended for perforation of the apical cortex of the dens by the lag screw. However, overpenetration of the apical cortex may lead to potentially serious complications such as damages of adjacent vascular and neural structures. The purpose of this study was to assess the role of three-dimensional computed tomography (CT) scan to evaluate the safe margin beyond dens tip to ventral dura for anterior odontoid screw fixation. METHODS: We retrospectively analyzed the three-dimensional CT scans of the cervical spines in 55 consecutive patients at our trauma center. The patients included 38 males and 17 females aged between 22 and 73 years (mean age±standard deviation, 45.8±14.2 years). Using sagittal images of 3-dimensional CT scan, the safe margins beyond dens tip to ventral dura as well as the appropriate screw length were measured. RESULTS: The mean width of the apical dens tip was 9.6±1.1 mm. The mean lengths from the screw entry point to the apical dens tip and posterior end of dens tip were 39.2±2.6 mm and 36.6±2.4 mm. The safe margin beyond apical dens tip to ventral dura was 7.7±1.7 mm. However, the safe margin beyond the posterior end of dens tip to ventral dura was decreased to 2.1±3.2 mm, which was statistically significant (p<0.01). There were no significant differences of safe margins beyond dens tip to ventral dura with patient gender and age. CONCLUSION: Extension by several millimeters beyond the dens tip is safe, if the trajectory of anterior odontoid screw is targeted at the apical dens tip. However, if the trajectory of the screw is targeted to the posterior end of dens tip, extension beyond dens tip may lead to damage immediately adjacent to the vental dura mater.