Yudo Hachiya

Vasogenic edema induced by compression injury to the spinal nerve root : distribution of intravenously injected protein tracers and gadolinium-enhanced magnetic resonance imaging

The function of the blood-nerve barrier appears quite unique in the nerve root. Protein tracers that were injected into the subarachnoid space passed through the nerve root sheath and entered into the capillary lumen in the endoneurial space but tracers that were injected intravenously did not appear in the endoneurial space. Marked extravasation of protein tracers in the nerve root was induced at the compressed part by strong compression (60 gram force, 30 gram force) and capillaries in the nerve root showed opening of the tight junction accompanied by an increase in vesicular transport under the electron microscope. This situation was reflected as high intensity on Gadolinium-enhanced magnetic resonance imaging. In twenty-one of fifty patients with lumbar disc herniation, the affected nerve root was strongly enhanced by Gadolinium-diethylene-triaminepentaacetic acid, indicating that the blood-nerve barrier in the affected nerve root was broken and intraradicular edema was produced in these cases.

Postoperative magnetic resonance imaging of lumbar disc herniation: comparison of microendoscopic discectomy and Love's method.

Study Design. We performed a study to compare the magnetic resonance imaging findings up to 24 weeks after microendoscopic discectomy or surgery using Love’s method in patients with lumbar disc herniation. Objectives. The objective was to determine whether or not microendoscopic discectomy was minimally invasive with respect to the nerve roots, cauda equina, and paravertebral muscles by comparing the postoperative magnetic resonance imaging findings in patients treated by microendoscopic discectomy and the conventional Love’s method. Summary of Background Data. We introduced microendoscopic discectomy as a minimally invasive surgical procedure for lumbar disc herniation in September 1998 and have obtained good results. Microendoscopic discectomy is superior to the conventional Love’s method in that it reduces postoperative pain, shortens the duration of hospitalization, and allows earlier resumption of normal activities. However, the effect of microendoscopic discectomy on the nerves and paravertebral muscles has not been evaluated objectively. Methods. Enhancement of the nerve roots and paravertebral muscles, as well as the configuration of the cauda equina at the level of herniation, was assessed on axial magnetic resonance images obtained with contrast enhancement using gadolinium-diethylenetriamine penta-acetic acid before surgery and 1, 4, 8, 12, and 24 weeks after surgery in 25 patients who underwent microendoscopic discectomy and 15 patients who were treated using Love’s method. Results. Increased enhancement of the nerve roots was seen in 50.0% of the microendoscopic discectomy group and 46.2% of the Love group at 1 week after surgery. Enhancement of the paravertebral muscles at the surgical site tended to persist for longer in the microendoscopic discectomy group than in the Love group. However, muscle enhancement was widespread in some patients from the Love group. Abnormalities of the cauda equina attributed to surgical invasion were seen in 12.5% of the microscopic discectomy group and 15.4% of the Love group at 1 week after surgery. Conclusions. Microendoscopic discectomy had an effect on the nerve roots and cauda equina that was comparable with that of Love’s method. The magnetic resonance images of the route of entry failed to show that microendoscopic discectomy is appreciably less invasive with respect to the paravertebral muscles.

An Arterial Pulse Examination Is Not Sufficient for Diagnosis of Peripheral Arterial Disease in Lumbar Spinal Canal Stenosis : A Prospective Multicenter Study

Study Design. Prospective, multicenter study. Objective. To conduct peripheral arterial disease (PAD) screening on intermittent claudication (IC) in patients with lumbar spinal canal stenosis (LSCS) to examine the relationships among combined LSCS and PAD, symptoms, and physical findings. Summary of Background Data. IC occurs due to two underlying diseases, LSCS and PAD, and has an increasing prevalence with the aging of society. Reliable diagnosis of PAD is critical for appropriate conservative management of IC patients with LSCS in an Orthopedic Surgery Outpatient Department (OSOPD). Methods. PAD tests were prospectively conducted in 201 patients with IC and LSCS who initially visited an OSOPD at a hospital affiliated with the Nogoya Spine Group. Occurrence of PAD as a complication was assessed using ankle brachial pressure index (ABI) and toe brachial pressure index (TBI) tests. PAD was diagnosed in patients with ABI ⩽ 0.9 or TBI ⩽ 0.6, and the relationship of the occurrence of PAD with symptoms and physical findings such as abnormal arterial pulses was investigated. Results. Combined LSCS and PAD was found in 52 patients (26%), with 45 cases (22%) diagnosed on the basis of TBI test in patients with a normal ABI. Of the patients with PAD, many suffered from risk factors for PAD, with a significantly higher frequency of PAD in patients with hyperlipidemia (P < 0.05). PAD also occurred significantly more frequently in patients with abnormal pulses in the popliteal (P < 0.05), posterior tibial (P < 0.0001), and dorsal pedis (P < 0.0001) arteries; however, the sensitivity of these tests for PAD diagnosis was relatively low, at 34%, 60% and 68%, respectively. Conclusion. The results of the prospective study define the rate of occurrence of combined LSCS and PAD using ABI and TBI tests for the first time, and the findings suggest that screening for PAD should be conducted in LSCS patients. ABI and TBI tests are necessary for PAD screening in outpatients, whereas observation of the arterial pulse in the lower extremities is necessary but not sufficient for PAD diagnosis.

Surgically treated cases of lumbar spondylolysis and isthmic spondylolisthesis: a multicenter study.

Study Design: Prospective database study. Objectives: To grasp the characteristics of surgically treated cases with lumbar spondylolysis or isthmic spondylolisthesis. Summary of Background Data: A detailed analysis of surgically treated cases with spondylolysis or isthmic spondylolisthesis has never been reported. An epidemiological study in Japan conducted on 2000 subjects found the incidence of lumbar spondylolysis in the Japanese general population (population-based study) to be 5.9% (males: 7.9%, females: 3.9%). Among 124 vertebrae with spondylolysis, there were 0.8% L2 lesions, 3.2% L3 lesions, 5.6% L4 lesions, and 90.3% L5 lesions, including 5 cases (4.3%) with multiple-level lesions. Methods: We have been registering surgically treated spine cases in our database since 2000. From this database, we prospectively collected cases with lumbar spondylolysis or isthmic spondylolisthesis that were treated surgically between January 2000 and December 2009. We determined the age at surgery, sex, and vertebral level of spondylolysis. Results: Of the 564 spondylolysis patients treated surgically, 66.8% were male and 33.2% were female. The mean age at surgery was 52.5 years (range, 13–84 y). There were 585 vertebrae with spondylolysis including 21 cases (3.7%) with multiple-level lesions. L5 spondylolysis affected 432 vertebrae and was the most common location (73.8%), followed by 125 L4 lesions (21.4%), 24 L3 lesions (4.1%), and 2 L2 lesions (0.7%). Conclusions: The percentage of L4 lesions in our study was significantly higher and of L5 lesions was significantly lower than those lesions’ percentages in the population-based study. L4 spondylolysis may be more unstable or cause clinical symptoms more frequently leading to more surgical intervention. The percentage of multiple-level spondylolysis was similar between the 2 studies, suggesting these patients respond relatively well to conservative treatment. The male/female ratio was 2:1 in both studies, indicating that males and females require surgery at a similar frequency.

Postoperative Complications Associated With Spine Surgery in Patients Older Than 90 Years: A Multicenter Retrospective Study

Study Design: A review of a prospective database. Objectives: Surgery for elderly patients is increasing yearly due to aging of society and the desire for higher quality of life. The goal of the study was to examine perioperative complications in spine surgery in such patients. Methods: A multicenter study of surgical details and perioperative complications was performed in 35 patients aged older than 90 years who underwent spinal surgery, based on a review of a prospective database. The frequency and severity of complications were assessed, and the effects of patient-specific and surgical factors were examined. Major complications were defined as those that were life threatening, required reoperation in the perioperative period or left a permanent injury. Ambulatory function before and after surgery was also analyzed. Results: Perioperative complications occurred in 19 of the 35 cases (54%), and included 11 cases of postoperative delirium, most of which occurred after cervical spine surgery. There were 8 major complications (23%), including cerebral infarction (n = 3), coronary heart disease (n = 3), pulmonary embolism (n = 1), and angina (n = 1). Preoperative motor deficit, operative time, estimated blood loss, and instrumented fusion were significantly associated with major complications. An improved postoperative ambulatory status occurred in 61% of cases, with no change in 33%, and worsening in 2 cases (6%). Conclusions: Timing of surgery before paralysis progression and reduced surgical invasiveness are important considerations in treatment of the very elderly. Improved outcomes can be obtained with better management of spine surgery for patients aged 90 years or older.

Predictors of Prolonged Length of Stay After Lumbar Interbody Fusion: A Multicenter Study

Study Design: Retrospective analysis of a prospectively database. Objectives: To identify factors associated with prolonged length of stay (LOS) in posterior /transforaminal lumbar interbody fusion (PLIF/TLIF). Methods: The subjects were patients who underwent PLIF/TLIF at 10 facilities from 2012 to 2014. A total of 1168 such patients with a mean age of 65.9 ± 12.5 years (range 18-87 years) were identified in the database. Operations were PLIF (n = 675), TLIF (n = 443), minimally invasive surgery (MIS)-PLIF (n = 22), and MIS-TLIF (n = 32). Age, gender, body mass index, ambulatory status, comorbidities, perioperative American Society of Anesthesiologists (ASA) grade, operative factors, and complications were examined. LOS was defined as the number of calendar days from the operation to hospital discharge. LOS was categorized as normal (<75th percentile) or prolonged (≥75th percentile). Results: The average LOS was 20.8 ± 9.8 days (range 7-77 days). There was a significant correlation between LOS and age (P < .05). Reoperation during hospitalization was performed in 20 cases for surgical site infection (n = 12), epidural hematoma (n = 5), and screw misplacement (n = 3). In multivariate analysis, prolonged LOS was associated with preoperative variables of age ≥70 years (odds ratio [OR] 1.87, 95% CI 1.38-2.54), and ASA class ≥III (OR 1.52, 95% CI 1.04-2.25); surgical variables of open procedures (OR 5.84, 95% CI 1.74-19.63), fused levels ≥3 (OR 5.17, 95% CI 3.17-8.43), operative time ≥300 minutes (OR 1.88, 95% CI 1.15-3.07), and estimated blood loss ≥500 mL (OR 1.71, 95% 1.07-2.75). Conclusions: The factors identified in this study should help with obtaining informed consent, surgical planning and complication prevention to reduce health care costs associated with prolonged LOS.