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.

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.

A Case of an Epidural Extension of Vertebral Hemangioma Treated by Intraoperative Vertebroplasty and Laminectomy

Vertebral hemangioma is relatively common, but rarely extends into the epidural space and causes neurological deficits. This case report describes a 69-year-old woman with vertebral hemangioma extending into the epidural space causing spinal cord compression. The patient presented with low back pain and progressive weakness of the left lower extremity over a period of 1 year. Radiologic findings revealed a dural encasing vertebral hemangioma with spinal cord compression at the T11 level. After T11 vertebroplasty, the lesion was subtotally removed by T10-11 total laminectomy. The patient regained motor power of the left lower extremity postoperatively. And no further tumor growth was observed at last follow-up. This combination of intraoperative vertebroplasty and decompressive laminectomy offers a viable treatment modality for a dural encasing vertebral hemangioma with epidural extension causing cord compression.

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.