Predictors for clinical outcomes of tubular surgery for endoscopic decompression in selected patients with lumbar spinal stenosis.

INTRODUCTION: The success rate of decompression surgery for lumbar spinal stenosis (LSS) has been reported to vary from 60 to 80%. The purpose of this study was to analyze the predictors for clinical outcomes after tubular surgery for endoscopic decompression (microendoscopic decompression) for LSS. MATERIALS AND METHODS: A total of 100 patients with degenerative LSS (M/F: 61/39, Age: mean 69.7 years), who underwent microendoscopic decompression and had a minimum 2-year follow-up (FU) after surgery, were reviewed. All patients suffered from leg-related symptoms predominantly without severe mechanical back pain, preoperatively. The presence of chronic arterial occlusion of the lower limbs was ruled out. The primary outcome measure was clinical evaluation at 2-year FU using the Oswestry Disability Index (ODI). Furthermore, numeric rating scales, Japanese Orthopedic Association (JOA) lumbar score and JOA Back Pain Evaluation Questionnaire were used for secondary outcome measures. Based on findings of univariable analyses, multivariable logistic regression analysis was applied to identify preoperative predictors for the clinical outcomes. RESULTS: Sixty-eight patients (68%) were assessed as good outcomes, on the basis of minimum clinically important difference of the ODI (13 points ≤) and final ODI score (< 30 points). The secondary outcomes were further support for the primary outcome. In multivariable logistic regression analysis, co-existence of intradiscal vacuum phenomenon with LSS (odds ratio [OR] 8.26; 95% confidence interval [95% CI] 2.32-29.34; p = 0.001) and ischemic cardiovascular comorbidities (OR, 13.3; 95% CI, 1.9-92.57; p = 0.009) were significantly associated with poor clinical outcomes. CONCLUSIONS: We found co-existence of intradiscal vacuum phenomenon with LSS and ischemic cardiovascular comorbidity to be preoperative predictors of less favorable clinical outcomes after microendoscopic decompression in selected patients of LSS. Although the conclusion obtained from restricted state, the information would be able to help in patient selection of the tubular surgery for endoscopic decompression for LSS.

Occipital bone erosion induced by C1 pedicle screw as a late complication of atlantoaxial fixation: a case report and literature review.

PURPOSE: The objective of this case report is to highlight occipital bone erosion as an unusual late complication of C1-C2 instrumented fixation. CASE PRESENTATION: A 60-year-old man of a displaced Anderson type II odontoid fracture was surgically treated by C1-C2 pedicle screw fixation. Occipital bone erosions, caused by a repeat irritation of the end of rod to the occipital bone, were detected on multiplane reconstructed computed tomography at 3 months after surgery. The lesion progressed over time with increasing the C2 anteversion on radiological evaluations. Eventually, the bony shell had been reactively formed around the protruded screw-rod construct and the Oc-C1 segment had been spontaneously stabilized. Fortunately, he had experienced no symptoms caused by the lesion at 5-year follow-up. CONCLUSION: The occipital bone erosion is an unusual late complication in C1-C2 posterior fixation using C1 pedicle screw. The increasing occipital-C1 lordosis compensating for the great C2 anteversion (high C2 slope) was related to the progression of the lesion. In C1-C2 pedicle screw fixation, surgeons should recognize a possibility of this complication and realize a relation between the occurrence of the lesion and the sagittal alignment of the cervical spine to take measures to avoid the complication.

[A case of minoxidil intoxication].

A 26-year-old man was found unable to move after oral consumption of 120 mL of RiUP X5® (containing 5 g/100 mL minoxidil) as a suicidal attempt. The patient complaining of frequent vomiting and weakness was transferred to our hospital. Findings on arrival: GCS E4V5M6; respiratory rate 24/ min; blood pressure 83/43 mmHg; pulse 152/min, regular; SpO297% (oxygen by mask: 6 L/min); thus, the patient was in shock. The systolic blood pressure and the pulse rate improved to about 90 mmHg and to about 130/min, respectively, in response to rapid intravenous infusion of 2,000 mL of lactated Ringer's solution. His circulatory condition tended to improve with parenteral fluid infusion alone. Forty hours after admission, however, heart failure developed due to excessive I.V. fluid infusion and abnormal body fluid distribution associated with delayed vascular smooth muscle relaxation; therefore, mechanical ventilation was initiated. Simultaneously, intravenous noradrenaline infusion was started because of a fall of the blood pressure. Subsequently, as the patient's respiratory and circulatory conditions gradually improved, he was weaned from mechanical ventilation, and the noradrenaline infusion was discontinued at 108 hours after admission. The patient made favorable progress and was discharged home on the 9th hospital day. Minoxidil exerts adverse effects mainly on the cardiovascular system. Since minoxidil is an over-the-counter drug readily available to the public, and emergency physicians should be aware of its severe toxicity.