Early Postoperative Magnetic Resonance Imaging in Detecting Radicular Pain After Lumbar Decompression Surgery: Retrospective Study of the Relationship Between Dural Sac Cross-sectional Area and Postoperative Radicular Pain.

STUDY DESIGN: A retrospective analysis. OBJECTIVE: To evaluate the association between early postoperative dural sac cross-sectional area (DCSA) and radicular pain. SUMMARY OF BACKGROUND DATA: The correlation between postoperative magnetic resonance imaging (MRI) findings and postoperative neurological symptoms after lumbar decompression surgery is controversial. METHODS: This study included 115 patients who underwent lumbar decompression surgery followed by MRI within 7 days postoperatively. There were 46 patients with early postoperative radicular pain, regardless of whether the pain was mild or similar to that before surgery. The intervertebral level with the smallest DCSA was identified on MRI and compared preoperatively and postoperatively. Risk factors for postoperative radicular pain were determined using univariate and multivariate analyses. Subanalysis according to absence/presence of a residual suction drain also was performed. RESULTS: Multivariate regression analysis showed that smaller postoperative DCSA was significantly associated with early postoperative radicular pain (per -10 mm; odds ratio, 1.26). The best cutoff value for radicular pain was early postoperative DCSA of 67.7 mm. Even with a cutoff value of <70 mm, sensitivity and specificity are 74.3% and 75.0%, respectively. Early postoperative DCSA was significantly larger before suction drain removal than after (119.7±10.1 vs. 93.9±5.4 mm). CONCLUSIONS: Smaller DCSA in the early postoperative period was associated with radicular pain after lumbar decompression surgery. The best cutoff value for postoperative radicular pain was 67.7 mm. Absence of a suction drain at the time of early postoperative MRI was related to smaller DCSA.

Characteristics of trunk control during crook-lying unilateral leg raising in different types of chronic low back pain patients.

STUDY DESIGN: Cross-sectional observational study. OBJECTIVE: To quantitatively clarify the characteristics of trunk control during unilateral leg-raising movement in different types of nonspecific chronic low back pain (NS-CLBP) patients who were identified by aggravation of symptoms during trunk movement. SUMMARY OF BACKGROUND DATA: Although there is a need to classify NS-CLBP patients for clinical decision making in physical therapy, the characteristics of trunk control during unilateral leg-raising movement in different types of NS-CLBP patients have not been quantitatively analyzed in previous studies by simultaneously measuring the lumbar spine movement, trunk muscle activity, and leg movement. METHODS: Thirty NS-CLBP patients, of whom 13 were aggravated by trunk flexion (flexion group) and 17 were aggravated by trunk extension (extension group), and 30 healthy controls performed crook-lying unilateral leg-raising movement on the painful side in patient group and the dominant leg in controls. During the unilateral leg-raising movement, pressure changes produced by the movement of the lumbar lordotic curve, measured by a custom-made recording device, were used as indices of the lumbar spine movement. Trunk muscle activities were recorded by surface electromyography and diagnostic ultrasonography. The pressure changes and trunk muscle activities were statistically compared among the 3 groups. RESULTS: At foot-off during unilateral leg-raising movement, the extension group demonstrated increase in pressure changes, whereas the flexion group and controls demonstrated decrease in pressure changes. Bilateral external obliques muscle activities in the extension group were significantly larger than those in the flexion group and controls (P < 0.05). CONCLUSION: This study demonstrated that the characteristics of trunk control during unilateral leg-raising movement were different depending on the types of NS-CLBP patients. These results indicate that patients with NS-CLBP might select compensatory trunk control strategies subconsciously to prevent the manifestation of LBP. These results also suggest the importance of the different characteristics of trunk control during active limb movement in the clinical reasoning process for the management of different types of NS-CLBP patients. LEVEL OF EVIDENCE: N/A.

Study of dural sac cross-sectional area in early and late phases after lumbar decompression surgery.

BACKGROUND CONTEXT: Lumbar magnetic resonance imaging (MRI) in the early phase after lumbar decompression surgery sometimes reveals an absence in the expansion of the dural sac, regardless of the presence or absence of clinical symptoms; the reason for such a condition is often difficult to explain. There are some reports that compared the dural sac area between the preoperative and early postoperative phases; however, no report exists that compares the early and late phases after lumbar decompression surgery. PURPOSE: The purpose of this study was to compare changes in the dural sac cross-sectional area (CSA) in the early and late phases after lumbar decompression surgery. Factors related to the insufficient increase in the postoperative dural sac CSA were also analyzed. STUDY DESIGN: The dural sac CSA preoperatively and in the early and late phases after lumbar decompression surgery was analyzed retrospectively. PATIENT SAMPLE: Of 105 patients who underwent lumbar decompression surgery and MRI within 1 week and again more than 1 month after surgery, 83 patients (38 men, 45 women; mean age 65.6 years) were included in this study. OUTCOME MEASURES: Cross-sectional areas of the dural sac. METHODS: The dural sac CSA was measured within 1 week (early phase) and more than 1 month (late phase) after surgery, using T2 axial plane MR images. The preoperative and the early and late postoperative CSAs were measured at the same site. The relationship between the dural sac area and age and presence of dural injury was also analyzed. RESULTS: The mean area of the dural sac preoperatively and in the early and late postoperative phases was 71.2±4.9, 102.2±5.7, and 164.1±6.9 mm(2), respectively. The mean area increased significantly (p<.001) between the preoperative and postoperative early phases and between the early and late postoperative phases. The dural sac area in the early (p=.16) and late (p=.086) phases did not differ significantly between patients aged 75 years or more and those aged less than 75 years. In the case of lumbar spinal stenosis, patients with a preoperative dural sac area of less than 60 mm(2) showed a significantly (p<.001) smaller dural sac area in the early and late postoperative phases, compared with patients with a preoperative dural sac area of 60 mm(2) or more. No significant increase was observed in the dural sac area with regard to the presence or absence of dural injury. CONCLUSIONS: The dural sac area increased significantly between the early and late postoperative phases. No significant difference in the dural sac CSA between the early and late postoperative phases was observed with regard to age or the presence/absence of dural sac injury. A smaller preoperative dural sac CSA resulted in a smaller dural sac CSA in the early and late postoperative phases.

The effect of a prostaglandin E1 derivative on the symptoms and quality of life of patients with lumbar spinal stenosis.

BACKGROUND: Quality of life (QOL) is a concern for patients with lumbar spinal stenosis (LSS). In this study, QOL was examined using the 5-item EuroQol (EQ-5D). METHODS: QOL and activities of daily living (ADL) were surveyed for 91 patients who visited 18 medical institutions in our prefecture and were diagnosed with LSS-associated intermittent claudication. A second survey was performed after ≥6 weeks for 79 of the subjects to evaluate therapy with limaprost (an oral prostaglandin E1 derivative) or etodolac (an NSAID). Symptoms, maximum walking time, QOL, ADL items, and relationships among these variables were investigated for all 91 patients. Leg pain, leg numbness, and low back pain while walking were surveyed by use of VAS scores (0-100). RESULTS: Leg pain, leg numbness, and low back pain while walking (VAS ≥25) were present in 83.5, 62.6, and 54.9 % of the patients in the first survey, and approximately half of the patients had a maximum walking time <15 min. The mean EQ-5D utility value for QOL was 0.59 ± 0.12. This value was significantly associated with maximum walking time (p = 0.030) based on classification of patients into groups with walking times <7.5, 7.5-15, 15-30, and >30 min, showing that maximum walking time affected health-related QOL. Of the 79 patients who completed the second survey, 56 had taken limaprost and 23 (control group) had received etodolac. Limaprost improved possible walking time, reduced ADL interference, and significantly increased the EQ-5D utility score, whereas no significant changes occurred in the control group. Maximum walking time was prolonged by ≥10 min and the EQ-5D utility value was improved by ≥0.1 points in significantly more patients in the limaprost group than in the control group. CONCLUSION: According to the findings of this survey, at an average of 8 weeks after administration limaprost improved symptoms, QOL, and ADL in LSS patients whereas treatment with an NSAID reduced pain but did not have any other effects.

Comparison between continuous and discontinuous multiple vertebral compression fractures.

BACKGROUND: The majority of multiple vertebral fractures (MVFs) occur under high-energy conditions; however, some cases occurring under minor-energy conditions exist. Fractures in successive vertebrae (continuous type) and in skipped vertebrae (discontinuous type) can exist. PURPOSE: The objective of this study was to compare and evaluate the cause, level of injury, and relationship to osteoporosis between continuous and discontinuous MVFs. METHODS: We studied 77 subjects (173 vertebrae) who had presented with acute back pain between September 2007 and April 2010 and who received diagnoses of fresh MVFs through magnetic resonance imaging. Subjects with continuous and discontinuous fractures were evaluated based on age, sex, bone mineral density (BMD), level of affected vertebrae, and cause of injury. RESULTS: Subjects with discontinuous MVFs were significantly older and comprised more female patients. Mean BMD, measured by dual-emission X-ray absorptiometry, was 0.70 and 0.58 g/cm(3) for the continuous and discontinuous MVFs, respectively, demonstrating a significant difference. Of 34 patients with discontinuous MVFs, 32 (94%) exhibited vertebral fractures in the thoracolumbar junction. In subjects with continuous MVFs, the MVFs of 19 (44%) subjects were caused by high-energy trauma, whereas mild trauma and unknown cause were identified in 14 (41%) and 13 (38%) subjects with discontinuous MVFs, respectively. CONCLUSIONS: Discontinuous MVFs generally caused by mild outer force, and often occurred at the thoracolumbar junction. Continuous MVFs, frequently, were caused by high-energy trauma.