Symptomatic adjacent segment degeneration at the L3-4 level after fusion surgery at the L4-5 level: evaluation of the risk factors and 10-year incidence.

PURPOSE: There have been few studies on revision surgery for clinically symptomatic adjacent segment degeneration (CASD). We aimed to find the incidence of revision surgery due to CASD and to analyze the factors that affected CASD at the L3-4 level after L4-5 or L4-5-S1 level fusion surgery over a long-term follow-up period. METHODS: Between January 2001 and October 2009, fusion surgeries were performed on 401 patients with spondylolisthesis at the L4-5 or L4-5-S1 level; 378 patients were followed up for a minimum of 2 years. We assessed CASD-free survival using Kaplan-Meier survival analysis. We also analyzed factors affecting the development of CASD, including sex, age, pelvic incidence, overall lordosis, segmental lordosis, lamina inclination angle, facet tropism, and the extent of disc and facet degeneration. Isthmic spondylolisthesis treated using total laminectomy or degenerative spondylolisthesis treated using subtotal laminectomy and interbody fusion (IBF) or posterolateral fusion (PLF) were also included in the risk factor analysis. The difference in disc height before and after initial surgery was also analyzed, as was inclusion of the sacrum in the fusion level. RESULTS: Fusion extension surgery was performed on 33 of these patients due to CASD at the L3-4 level during the follow-up period. Kaplan-Meier survival analysis indicated 3-, 5-, and 10-year disease-free survival rates of 99.20, 96.71, and 76.93 %. Statistically significant factors affecting CASD included old age, low overall lordosis, low segmental lordosis, progression of facet degeneration, total laminectomy-treated isthmic spondylolisthesis, and PLF-alone rather than IBF alone or IBF + PLF. CONCLUSION: We determined six significant factors affecting CASD development. Among these risk factors, facet degeneration, isthmic-type spondylolisthesis, and the type of fusion show higher hazard ratios and seem to be clinically more relevant than the other three factors (age, overall lordosis, and segmental lordosis).

Analysis on bilateral hindlimb mapping in motor cortex of the rat by an intracortical microstimulation method.

Intracortical microstimulation (ICMS) is a technique that was developed to derive movement representation of the motor cortex. Although rats are now commonly used in motor mapping studies, the precise characteristics of rat motor map, including symmetry and consistency across animals, and the possibility of repeated stimulation have not yet been established. We performed bilateral hindlimb mapping of motor cortex in six Sprague-Dawley rats using ICMS. ICMS was applied to the left and the right cerebral hemisphere at 0.3 mm intervals vertically and horizontally from the bregma, and any movement of the hindlimbs was noted. The majority (80%± 11%) of responses were not restricted to a single joint, which occurred simultaneously at two or three hindlimb joints. The size and shape of hindlimb motor cortex was variable among rats, but existed on the convex side of the cerebral hemisphere in all rats. The results did not show symmetry according to specific joints in each rats. Conclusively, the hindlimb representation in the rat motor cortex was conveniently mapped using ICMS, but the characteristics and inter-individual variability suggest that precise individual mapping is needed to clarify motor distribution in rats.

Comparison of Surgical Results between Soft Ruptured Disc and Foraminal Stenosis Patients in Posterior Cervical Laminoforaminotomy.

OBJECTIVE: Posterior cervical laminoforaminotomy is used to relieve cervical nerve root compression caused by a laterally herniated soft cervical disc or spondylotic spur and its several advantages and disadvantages compared with anterior cervical discectomy were reported. We compared surgical results between soft ruptured disc and foraminal stenosis in posterior cervical laminoforaminotomy. METHODS: We performed a retrospective review of 47 patients performed single level posterior cervical laminoforaminotomy for cervical radiculopathy between 2004 and 2012. We divided these patients into two groups, Group A: 27 patients for ruptured disc and Group B: 20 patients for foraminal stenosis and analyzed the demographic factors, amount of medial facetectomy, postoperative instability with neck pain and clinical outcomes. RESULTS: According to the modified Odom's criteria, laminoforaminotomy for the ruptured disc showed 92.6% excellent results and 7.4% good results. For the foraminal stenosis, it was 55.0% excellent and 25.0% good results, which was statistically significant. However when both groups were included, overall success rate showed 91.5%. The extent of medial facetectomy for ruptured disc (31.2%) was smaller than for stenosis (48.8%) and it was statistically significant. Thirteen patients complained of postoperative neck pain for 2 months. There was no instability on dynamic X-ray until the last follow up period and we had two cases complications (4.3%). CONCLUSION: Although the extent of facetectomy for ruptured disc was smaller than it for stenosis, posterior laminoforaminotomy for the ruptured disc showed the better outcomes than foraminal stenosis.

Feasibility of Posterior Cervical Foraminotomy in Cervical Foraminal Stenosis: Prediction of Surgical Outcomes by the Foraminal Shape on Preoperative Computed Tomography.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The aim of this study was to compare the feasibility of posterior cervical laminoforaminotomy (PCF) for V- or parallel-shaped foraminal stenosis (FS). SUMMARY OF BACKGROUND DATA: During PCF, the need for extensive facet resection would depend on the extent of any pathology. When resection is extensive, the possibilities of instability and incomplete decompression should be considered. METHODS: From March 2004 to March 2015, we enrolled 36 patients following single-level PCF procedures for FS. We classified patients by foraminal shape on preoperative computed tomography (CT) scan into V-shaped and parallel-shaped groups. We then compared arm and neck pain using a numeric rating scale (NRS) and clinical outcomes using Odom criteria. Radiological evaluation included dynamic X-rays for instability and CT scans for facet resection. RESULT: We enrolled 16 and 20 patients in the V-shape and parallel-shape groups, respectively. By Odom criteria, no patient was graded fair or poor in the V group, but five patients were graded as fair and one patient as poor in the parallel group. Continued postoperative arm pain at 1 year, which was related to incomplete decompression, was significantly higher in parallel group. Only one patient complained of postoperative neck pain with an NRS >5, and another five patients sustained radiculopathy with an NRS >5. Among five patients who complained sustained radiculopathy, one patient required revision surgery for incomplete decompression. The amount of facet removal was not different significantly between groups, and no patient had postoperative instability. CONCLUSION: Although PCF seems to be a good surgical option for V-shaped FS, we experienced worse outcomes for patients with parallel-shaped FS. We recommend that ACDF or more aggressive posterior foraminotomy be performed with fusion when presented with parallel neuroforaminal compression. LEVEL OF EVIDENCE: 4.

Prognostic Factor Analysis for Management of Chronic Neck Pain: Can We Predict the Severity of Neck Pain with Lateral Cervical Curvature?

OBJECTIVE: Although little is known about its origins, neck pain may be related to several associated anatomical pathologies. We aimed to characterize the incidence and features of chronic neck pain and analyze the relationship between neck pain severity and its affecting factors. METHODS: Between March 2012 and July 2013, we studied 216 patients with chronic neck pain. Initially, combined tramadol (37.5 mg) plus acetaminophen (325 mg) was administered orally twice daily (b.i.d.) to all patients over a 2-week period. After two weeks, patients were evaluated for neck pain during an outpatient clinic visit. If the numeric rating scale of the patient had not decreased to 5 or lower, a cervical medial branch block (MBB) was recommended after double-dosed previous medication trial. We classified all patients into two groups (mild vs. severe neck pain group), based on medication efficacy. Logistic regression tests were used to evaluate the factors associated with neck pain severity. RESULTS: A total of 198 patients were included in the analyses, due to follow-up loss in 18 patients. While medication was successful in reducing pain in 68.2% patients with chronic neck pain, the remaining patients required cervical MBB. Lateral cervical curvature, such as a straight or sigmoid type curve, was found to be significantly associated with the severity of neck pain. CONCLUSION: We managed chronic neck pain with a simple pharmacological management protocol followed by MBB. We should keep in mind that it may be difficult to manage the patient with straight or sigmoid lateral curvature only with oral medication.

A Case of Intracranial Wooden Foreign Body: Mimicking Pneumocephalus.

Intracranial wooden foreign bodies are rare. In addition, such objects are difficult to identify with conventional radiographic techniques, such as X-ray radiography or brain computed tomography. A 48-year-old man presented to our emergency room with a headache. Even though he had a history of trauma, he had no external wounds and showed no neurological deficits at the initial examination. He was initially diagnosed with trauma-related pneumocephalus. He developed a delayed intracranial infection and underwent surgery to remove the wooden foreign body. The present case illustrates the necessity for special attention to patients suspected of having pneumocephalus with a rare presentation during the initial examination. Early surgical removal of the intracranial foreign body is necessary to prevent complications.

Thoracic Extradural Cavernous Hemangioma Mimicking a Dumbbell-Shaped Tumor.

Dumbbell-shaped spinal extradural cavernous hemangioma is rare. The differential diagnosis of dumbbell-shaped spinal tumors based on magnetic resonance imaging includes schwannoma and lymphoma. Here, we report a dumbbell-shaped spinal extradural cavernous hemangioma with intrathoracic growth on T2-3 in a 64-year-old man complaining of right side infrascapular area back pain with no neurologic deficit. The cavernous hemangioma was resected through combined video-assisted thoracoscopy and laminectomy without a fusion procedure. The patient had tolerable operative wound pain with no neurologic deficit after surgery. Based on magnetic resonance imaging findings and a review of the literature, we discuss cavernous hemangioma among the differential diagnosis of paravertebral dumbbell-shaped spinal tumors and the importance of complete resection.

Syringomyelia Associated with a Huge Retrocerebellar Arachnoid Cyst: A Case Report.

Occasionally, a posterior fossa arachnoid cyst can induce compression of the spinal cord and cause syringomyelia. Here, we report the case of a 29-year-old man with both progressive shoulder pain and gait disturbance, who was found to have a huge retrocerebellar arachnoid cyst associated with syringomyelia. Accordingly, posterior fossa decompression and arachnoid cyst excision were performed. Post-operative MRI showed a marked reduction in the size of the arachnoid cyst and syringomyelia. The patient's symptoms were clearly improved compared to before surgery. In our view, treatment in such patients should focus on decompressing the foramen magnum and include the removal of the coexistent arachnoid cyst walls, which appear to be the crucial factor in development of syringomyelia. In this report, we discuss the pathogenic mechanisms underlying syringomyelia-associated retrocerebellar arachnoid cyst and review the current literature on this topic.

Extra-intradural Spinal Meningioma: A Case Report.

Extradural spinal meningiomas are uncommon, and their pathophysiology is not entirely understood. Here, we present the case of a 49-year-old woman with low back and left leg pain of 5 years duration. Magnetic resonance imaging revealed a mass, 1.8-cm in size, with rim enhancement in the spinal canal at the T12 level and extending into the left T12-L1 foramen. In the surgical field, the mass presented with the characteristics of an extra-intradural spinal meningioma. The patient underwent a T12 total laminectomy. A linear durotomy was performed at the midline, and the intradural portion was removed. The extradural portion was not separable from the adjacent dura and the left T12 root, and it was removed by dural excision. Pathological examination confirmed the diagnosis of psammomatous meningioma. We also conducted a literature review of similar cases. Based on our experience with this case, we believe that it is important to clearly distinguish extradural meningiomas from other types of tumors as misdiagnosis can change the operative plan. The long term prognosis of extradural meningiomas is not clear but total excision is thought to be essential.

Spinal extradural arachnoid cyst.

Spinal extradural arachnoid cyst (SEAC) is a rare disease and uncommon cause of compressive myelopathy. The etiology remains still unclear. We experienced 2 cases of SEACs and reviewed the cases and previous literatures. A 59-year-old man complained of both leg radiating pain and paresthesia for 4 years. His MRI showed an extradural cyst from T12 to L3 and we performed cyst fenestration and repaired the dural defect with tailored laminectomy. Another 51-year-old female patient visited our clinical with left buttock pain and paresthesia for 3 years. A large extradural cyst was found at T1-L2 level on MRI and a communication between the cyst and subarachnoid space was illustrated by CT-myelography. We performed cyst fenestration with primary repair of dural defect. Both patients' symptoms gradually subsided and follow up images taken 1-2 months postoperatively showed nearly disappeared cysts. There has been no documented recurrence in these two cases so far. Tailored laminotomy with cyst fenestration can be a safe and effective alternative choice in treating SEACs compared to traditional complete resection of cyst wall with multi-level laminectomy.