Which one is a valuable surrogate for predicting survival between Tomita and Tokuhashi scores in patients with spinal metastases? A meta-analysis for diagnostic test accuracy and individual participant data analysis.

This study is to estimate the diagnostic accuracy of Tokuhashi and Tomita scores that assures 6-month predicting survival regarded as a standard of surgical treatment. We searched PubMed, EMBASE, European PubMed central, and the Cochrane library for papers about the sensitivities and specificities of the Tokuhashi and/or Tomita scores to estimate predicting survival. Studies with cut-off values of ≥9 for Tokuhashi and ≤7 for Tomita scores based on prior studies were enrolled. Sensitivity, specificity, diagnostic odds ratio (DOR), area under the curve (AUC), and the best cut-off value were calculated via meta-analysis and individual participant data analysis. Finally, 22 studies were enrolled in the meta-analysis, and 1095 patients from 8 studies were included in the individual data analysis. In the meta-analysis, the pooled sensitivity/specificity/DOR for 6-month survival were 57.7 %/76.6 %/4.70 for the Tokuhashi score and 81.8 %/47.8 %/4.93 for Tomita score. The AUC of summary receiver operating characteristic plots was 0.748 for the Tokuhashi score and 0.714 for the Tomita score. Although Tokuhashi score was more accurate than Tomita score slightly, both showed low accuracy to predict 6 months residual survival. Moreover, the best cut-off values of Tokuhashi and Tomita scores were 8 and 6, not 9 and 7, for predicting 6-month survival, respectively. Estimation of 6-month predicting survival to decide surgery in patients with spinal metastasis is quite limited by using Tokuhashi and Tomita scores alone. Tokuhashi and Tomita scores could be incorporated as part of a multidisciplinary approach or perhaps interpreted in the context of a multidisciplinary approach.

Chiari I malformation associated with syringomyelia: can foramen magnum decompression lead to restore cervical alignment?

PURPOSE: There are few researches that demonstrate the relationship between the extent of syringomyelia and sagittal alignment of the cervical spine. The purpose of this study is to investigate the correlation between the change of syrinx size and cervical alignment. METHODS: From January 2001 to June 2008, we operated on 207 patients who had syringomyelia. The associated diseases were categorized by Chiari I malformation, tumor, trauma, spinal stenotic lesion, inflammatory disease and idiopathic causes. Thirty patients who had Chiari I malformation associated with syringomyelia and who underwent foramen magnum decompression (FMD), participated in this study. We excluded patients with scoliosis, cervical instrumentation, tumor, trauma, myelomeningocele, hydrocephalus, tethered cord and congenital vertebral anomalies. Lateral radiographs in neutral and magnetic resonance imaging were taken pre- and postoperatively. RESULTS: Mean follow-up was 6.5 ± 1.5 years (ranged from 4.0 to 9.5 years). The mean pre- and postoperative lordosis angles at C2-C7 were -5.9° ± 1.0° and -10.4° ± 1.0°, respectively (P = 0.001). There was significant correlation between the differences of syrinx width and the cervical lordotic angles before and after surgery (P = 0.016). After FMD, syringomyelia and cervical alignment improved in 28 (93.3%) and 25 (85.18%) of 30 patients, respectively. There was significant correlation between recovery rate by Japanese Orthopaedic Association scores and the difference of the cervical lordotic angles before and after surgery (P = 0.022). CONCLUSIONS: The present results demonstrate that the decrease of syrinx size by FMD may restore the cervical lordosis. We suggest that the postoperative cervical alignment might be a predictive factor for neurological outcome.

Back muscle changes after pedicle based dynamic stabilization.

OBJECTIVE: Many studies have investigated paraspinal muscle changes after posterior lumbar surgery, including lumbar fusion. However, no study has been performed to investigate back muscle changes after pedicle based dynamic stabilization in patients with degenerative lumbar spinal diseases. In this study, the authors compared back muscle cross sectional area (MCSA) changes after non-fusion pedicle based dynamic stabilization. METHODS: Thirty-two consecutive patients who underwent non-fusion pedicle based dynamic stabilization (PDS) at the L4-L5 level between February 2005 and January 2008 were included in this retrospective study. In addition, 11 patients who underwent traditional lumbar fusion (LF) during the same period were enrolled for comparative purposes. Preoperative and postoperative MCSAs of the paraspinal (multifidus+longissimus), psoas, and multifidus muscles were measured using computed tomographic axial sections taken at the L4 lower vertebral body level, which best visualize the paraspinal and psoas muscles. Measurements were made preoperatively and at more than 6 months after surgery. RESULTS: Overall, back muscles showed decreases in MCSAs in the PDS and LF groups, and the multifidus was most affected in both groups, but more so in the LF group. The PDS group showed better back muscle preservation than the LF group for all measured muscles. The multifidus MCSA was significantly more preserved when the PDS-paraspinal-Wiltse approach was used. CONCLUSION: Pedicle based dynamic stabilization shows better preservation of paraspinal muscles than posterior lumbar fusion. Furthermore, the minimally invasive paraspinal Wiltse approach was found to preserve multifidus muscles better than the conventional posterior midline approach in PDS group.

Comparison of the biomechanical effect of pedicle-based dynamic stabilization: a study using finite element analysis.

BACKGROUND CONTEXT: Recently, nonfusion pedicle-based dynamic stabilization systems (PBDSs) have been developed and used in the management of degenerative lumbar spinal diseases. Still effects on spinal kinematics and clinical effects are controversial. Little biomechanical information exists for providing biomechanical characteristics of pedicle-based dynamic stabilization according to the PBDS design before clinical implementation. PURPOSE: To investigate the effects of implanting PBDSs into the spinal functional unit and elucidate the differences in biomechanical characteristics according to different materials and design. STUDY DESIGN: The biomechanical effects of implantation of PBDS were investigated using the nonlinear three-dimensional finite element model of L4-L5. METHODS: An already validated three-dimensional, intact osteoligamentous L4-L5 finite element model was modified to incorporate the insertion of pedicle screws. The implanted models were constructed after modifying the intact model to simulate postoperative changes using four different fixation systems. Four models instrumented with PBDS (Dynesys, NFlex, and polyetheretherketone [PEEK]) and rigid fixation systems (conventional titanium rod) were developed for comparison. The instrumented models were compared with those of the intact and rigid fixation model. Range of motion (ROM) in three motion planes, center of rotation (COR), force on the facet joint, and von Mises stress distribution on the vertebral body and implants with flexion-extension were compared among the models. RESULTS: Simulated results demonstrated that implanted segments with PBDSs have limited ROM when compared with the intact spine. Flexion motion was the most limited, and axial rotation was the least limited, after device implantation. Among the PBDS selected in this analysis, the NFlex system had the closest instantaneous COR compared with the intact model and a higher ROM compared with other PBDS. Contact force on the facet joint in extension increased with an increase of moment in Dynesys and NFlex; however, the rigid or PEEK rod fixation revealed no facet contact force. CONCLUSIONS: Implanted segments with PBDSs have limited ROM when compared with the intact spine. Center of rotation and stress distribution differed according to the design and materials used. These biomechanical effects produced a nonphysiological stress on the functional spinal unit when they were implanted. The biomechanical effects of current PBDSs should be carefully considered before clinical implementation.

Postoperative survival and ambulatory outcome in metastatic spinal tumors : prognostic factor analysis.

OBJECTIVE: The purposes of this study are to estimate postoperative survival and ambulatory outcome and to identify prognostic factors thereafter of metastatic spinal tumors in a single institute. METHODS: We reviewed the medical records of 182 patients who underwent surgery for a metastatic spinal tumor from January 1987 to January 2009 retrospectively. Twelve potential prognostic factors (age, gender, primary tumor, extent and location of spinal metastases, interval between primary tumor diagnosis and metastatic spinal cord compression, preoperative treatment, surgical approach and extent, preoperative Eastern Cooperative Oncology Group (ECOG) performance status, Nurick score, Tokuhashi and Tomita score) were investigated. RESULTS: The median survival of the entire patients was 8 months. Of the 182 patients, 80 (44%) died within 6 months after surgery, 113 (62%) died within 1 year after surgery, 138 (76%) died within 2 years after surgery. Postoperatively 47 (26%) patients had improvement in ambulatory function, 126 (69%) had no change, and 9 (5%) had deterioration. On multivariate analysis, better ambulatory outcome was associated with being ambulatory before surgery (p=0.026) and lower preoperative ECOG score (p=0.016). Survival rate was affected by preoperative ECOG performance status (p<0.001) and Tomita score (p<0.001). CONCLUSION: Survival after metastatic spinal tumor surgery was dependent on preoperative ECOG performance status and Tomita score. The ambulatory functional outcomes after surgery were dependent on preoperative ambulatory status and preoperative ECOG performance status. Thus, prompt decompressive surgery may be warranted to improve patient's survival and gait, before general condition and ambulatory function of patient become worse.

Primary intradural extramedullary melanoma of the cervical spinal cord: case report.

STUDY DESIGN: Case report. OBJECTIVE: We report a case of primary intradural extramedullary melanoma of the cervical spinal cord in a nonwhite patient. SUMMARY OF BACKGROUND DATA: Melanoma occurs most commonly in white populations and is rare in Asian populations. Primary malignant melanoma of the spinal cord is a rare disease entity that predominately affects the middle or lower thoracic spine. METHODS: A 39-year-old man presented with a tingling sensation in the upper extremities accompanied by motor weakness of the lower extremities. Preoperative magnetic resonance imaging (MRI) of the cervical spine suggested a multiloculated subdural hematoma in the subacute stage that spread from the level of C1 to the level of C6. RESULTS: A standard posterior midline approach was used under the impression that the subacute subdural hematoma was caused by a hidden vascular anomaly or a rare, intradural, pigmented tumor. A dark black-colored, hard, intradural mass was found, and gross total removal was performed. Histopathological investigation confirmed malignant melanoma. No hypermetabolic lesions were noted on whole-body FDG-PET. Additional dermatologic and ophthalmologic examinations did not reveal any other foci of primary melanoma. The patient was discharged with improvement of motor weakness. Subsequent radiotherapy and chemotherapy were administered. CONCLUSION: Unlike most cases of primary intradural melanoma, this patient presented with unusual radiologic findings in the cervical spinal cord. The case described in the present study illustrates that primary spinal cord melanoma is rare and must be diagnosed with caution due to its variable clinical and radiologic presentation.

Spontaneous intracerebral hematoma from transient occult carotid-cavernous fistula: a case report.

After the spontaneous relief of initial symptoms by traumatic carotid-cavernous fistula (CCF), paradoxical worsening of patient's condition can be followed. We present a case of a 60-yr-old man whose audible bruit from a traumatic CCF had completely disappeared. A few days later, however, the patient had spontaneous intracerebral hematoma with cortical venous drainage. Complete obliteration of the fistula was achieved after embolization. When initial audible bruit in traumatic CCF disappears suddenly, cerebral angiography should be performed to differentiate venous hypertension by the hemodynamic changes of the cavernous sinus channels from spontaneous resolution of CCF.