Neurological Complications of Posterior Spinal Surgery: Incidence and Clinical Features

STUDY DESIGN: Retrospective study. OBJECTIVES: To identify clinical features and risk factors helpful for the prevention and early diagnosis of neurological complications. OVERVIEW OF LITERATURE: Previous studies have investigated postoperative complications only for specific disease entities and did not present distinctive clinical features. MATERIALS AND METHODS: This was an observational study of patients who underwent posterior thoracolumbar spinal surgery in the orthopedic department of a single hospital over the course of 19 years (1995-2013). The incidence, cause, onset time, and risk factors of complications were investigated. Neurological deterioration was graded on a 5-point numeric scale: G1, increased leg pain or sensory loss, G2, unilateral motor weakness; G3, bilateral motor weakness; G4, cauda equina syndrome; and G5, complete paraplegia. RESULTS: Sixty-five cases out of 6574 (0.989%) developed neurological complications due to the following causes: epidural hematoma, 0.380%; instrumentation with inadequate decompression, 0.213%; mechanical injury, 0.167%; inadequate discectomy, 0.061%; and unknown cause, 0.167% (p=0.000). The grade of neurological deterioration was G1 in 0.167% of patients, G2 in 0.517%, G3 in 0.228%, G4 in 0.046%, and G5 in 0.030%. Neurological deterioration was most severe in patients who experienced epidural hematoma, followed by those in whom complications occurred due to instrumentation with inadequate decompression, unknown causes, mechanical injury, and inadequate discectomy, in order (p=0.009). Revision surgery was a significant risk factor (p=0.000; odds ratio, 2.741). The time that elapsed until symptom development was as follows, in order: unknown cause, 0.6 hours; epidural hematoma, 5.4 hours; mechanical injury, 6.6 hours; inadequate discectomy, 18.0 hours; and instrumentation with insufficient decompression, 36.0 hours (p=0.001). CONCLUSIONS: The incidence of neurological complications in our cohort was 1%. Revision surgery increased the risk by 3 times. Severe cases (cauda equina syndrome or complete paraplegia) rarely developed, occurring in 0.08% of patients. The major causes of neurological decline were epidural hematoma and instrumentation with inadequate decompression. Close observation in the early period was important for the diagnosis because most patients developed symptoms within 12 hours. Delayed diagnosis was most common in complications caused by instrumentation with inadequate decompression.

Neurological Complications of Posterior Spinal Surgery: Incidence and Clinical Features

OBJECTIVES@#To identify clinical features and risk factors helpful for the prevention and early diagnosis of neurological complications.OVERVIEW OF LITERATURE: Previous studies have investigated postoperative complications only for specific disease entities and did not present distinctive clinical features.@*MATERIALS AND METHODS@#This was an observational study of patients who underwent posterior thoracolumbar spinal surgery in the orthopedic department of a single hospital over the course of 19 years (1995-2013). The incidence, cause, onset time, and risk factors of complications were investigated. Neurological deterioration was graded on a 5-point numeric scale: G1, increased leg pain or sensory loss, G2, unilateral motor weakness; G3, bilateral motor weakness; G4, cauda equina syndrome; and G5, complete paraplegia.@*RESULTS@#Sixty-five cases out of 6574 (0.989%) developed neurological complications due to the following causes: epidural hematoma, 0.380%; instrumentation with inadequate decompression, 0.213%; mechanical injury, 0.167%; inadequate discectomy, 0.061%; and unknown cause, 0.167% (p=0.000). The grade of neurological deterioration was G1 in 0.167% of patients, G2 in 0.517%, G3 in 0.228%, G4 in 0.046%, and G5 in 0.030%. Neurological deterioration was most severe in patients who experienced epidural hematoma, followed by those in whom complications occurred due to instrumentation with inadequate decompression, unknown causes, mechanical injury, and inadequate discectomy, in order (p=0.009). Revision surgery was a significant risk factor (p=0.000; odds ratio, 2.741). The time that elapsed until symptom development was as follows, in order: unknown cause, 0.6 hours; epidural hematoma, 5.4 hours; mechanical injury, 6.6 hours; inadequate discectomy, 18.0 hours; and instrumentation with insufficient decompression, 36.0 hours (p=0.001).@*CONCLUSIONS@#The incidence of neurological complications in our cohort was 1%. Revision surgery increased the risk by 3 times. Severe cases (cauda equina syndrome or complete paraplegia) rarely developed, occurring in 0.08% of patients. The major causes of neurological decline were epidural hematoma and instrumentation with inadequate decompression. Close observation in the early period was important for the diagnosis because most patients developed symptoms within 12 hours. Delayed diagnosis was most common in complications caused by instrumentation with inadequate decompression.

Cement Mantle Thickness at the Bone Cement Interface in Total Knee Arthroplasty: Comparison of PS150 RP and LPS-Flex Knee Implants

PURPOSE: To analyze the thickness of cement mantle at the bone cement interface in knees with closed and open box designs in total knee arthroplasty (TKA). MATERIALS AND METHODS: Eighty cases of TKA were performed from October 2013 to March 2014. The average age of the patients was 68.4 years. All patients were women and they were divided into two groups: group I with a closed box implant (PS150 RP, n=40) and group II with an open box implant (LPS-Flex, n=40). We measured the cement mantle thickness at the bone cement interface from the distal femur and proximal tibia. If the thickness was >1 mm, it was considered an outlier. RESULTS: The mean cement mantle thickness at the interface was 1.4 mm in the distal femur and 0.8 mm in the proximal tibia. The value exceed 1 mm in 40 cases (50%) in the distal femur and in 6 cases (7.5%) in the proximal tibia (p<0.001). The mean cement mantle thickness measured in the distal femur was 1.7 mm in group I and 1.0 mm in group II. The value exceed 1 mm in 32 cases (80%) in group I and in 8 cases (20%) in group II (p<0.000). CONCLUSIONS: The cement mantle at the interface was thicker in the knees with the closed box implant than those with the open box implant in TKA, especially in the distal femoral area. A thick cement mantle at the interface should be avoided because it affects the gap balance. In case of using a closed box implant in TKA, cementing should be performed with extra care.

Why Cannot Suction Drains Prevent Postoperative Spinal Epidural Hematoma?

BACKGROUND: Postoperative spinal epidural hematoma (POSEH) is different from spontaneous or post-spinal procedure hematoma because of the application of suction drains. However, it appeared that suction drains were not effective for prevention of POSEH in previous studies. The purpose of this study was to test our hypothesis that POSEH can be caused by hypercoagulability. METHODS: This was an experimental study. One hundred fifty milliliters of blood was donated from each of the 12 consecutive patients who underwent spine surgery and infused into 3 saline bags of 50 mL each. One of the 3 bags in each set contained 5,000 units of thrombin. All of them were connected to 120 ± 30 mmHg vacuum suctions: drainage was started 8 minutes after connection to the vacuum system for 12 normal blood bags (BV8) and 12 thrombin-containing blood bags (TBV8) and 15 minutes after connection for the remaining 12 normal blood bags (BV15). The amount of initial and remaining hematoma at 20 minutes, 120 minutes, and 24 hours after vacuum application were measured by their weight (g). The primary endpoint was the difference between BV8 and TBV8. The secondary end point was the difference between BV8 and BV15. RESULTS: The remaining hematoma in TBV8 was significantly greater than that in BV8 at all measurement points: 46.3 ± 12.4 vs. 17.0 ± 1.3 (p = 0.000) at 20 minutes; 33.0 ± 8.2 vs. 16.3 ± 1.2 (p = 0.000) at 120 minutes; and 26.1 ± 4.0 vs. 15.8 ± 1.6 (p = 0.000) at 24 hours after vacuum application. The remaining hematoma of BV15 was significantly greater than that of BV8 at all measurement points: 30.0 ± 12.0 vs. 17.0 ± 1.3 (p = 0.002) at 20 minutes; 24.2 ± 7.6 vs. 16.3 ± 1.2 at 120 minutes (p = 0.002); and 22.2 ± 6.6 vs. 15.8 ± 1.6 (p = 0.004) at 24 hours after vacuum application. CONCLUSIONS: With a suction drain in place, the amount of remaining hematoma could be affected by coagulability. Thrombin-containing local hemostatics and the length of time elapsed before the commencement of suction resulted in hypercoagulability, indicating these two factors could be causes of POSEH.