The Influence of Systolic Blood Pressure at the Time of Extubation on the Development of Postoperative Spinal Epidural Hematoma

Background@#The most common cause of neurological complications after a biportal endoscopic spine surgery (BESS) is postoperative spinal epidural hematomas (POSEH). The objective of this study was to determine the influence of systolic blood pressure at extubation (e-SBP) on POSEH. @*Methods@#A total of 352 patients who underwent single-level decompression surgery including laminectomy and/or discectomy with BESS under the diagnosis of spinal stenosis and herniated nucleus pulposus between August 1, 2018, and June 30, 2021, were reviewed retrospectively. The patients were divided into two, a POSEH group and a normal group without POSEH (no neurological complication). The e-SBP, demographic factors, and the preoperative and intraoperative factors suspected to influence the POSEH were analyzed. The e-SBP was converted to a categorical variable by the threshold level that was decided by maximum area under the curve (AUC) in receiver operating characteristic (ROC) curve analysis. Antiplatelet drugs (APDs) were taken in 21 patients (6.0%), discontinued in 24 patients (6.8%), and not taken in 307 patients (87.2%). Tranexamic acid (TXA) was used in 292 patients (83.0%) in the perioperative period. @*Results@#Of the 352 patients, 18 patients (5.1%) underwent revision surgery for the removal of POSEH. The POSEH and normal groups were homogenous in age, sex, diagnosis, operation segments, operation time, and lab findings that were related to blood clotting, whereas there were differences in e-SBP (163.7 ± 15.7 mmHg in POSEH group and 154.1 ± 18.3 mmHg in normal group), APD (4 takers, 2 stoppers, 12 non-takers in POSEH group and 16 takers, 22 stoppers, 296 non-takers in normal group), and TXA (12 use, 6 not use in POSEH group and 280 use, 54 not use in normal group) in single variable analysis. The highest AUC in the ROC curve analysis was 0.652 for 170 mmHg e-SBP (p < 0.05). There were 94 patients in the high e-SBP group (≥ 170 mmHg) and 258 patients in the low e-SBP group. In multivariable logistic regression analysis, only high e-SBP was a significant risk factor for POSEH (p = 0.013; odds ratio, 3.434). @*Conclusions@#High e-SBP (≥ 170 mmHg) can influence the development of POSEH in biportal endoscopic spine surgery.

Posterior Surgery with Selective Anterior Reinforcement and Screw Augmentation for a Delayed Myelopathy from an Osteoporotic Vertebral Compression Fracture / 대한정형외과학회잡지

Purpose@#In delayed myelopathy (DM) from osteoporotic vertebral compression fractures (OVCF), the mechanisms of spinal cord impingement differ according to the stability of the fractured vertebra. This study examined the availability of a posterior surgery comprised of pedicle screw augmentation with polymethylmethacrylate (PMMA) and selective anterior reinforcement (PS-PMMA+SAR) according to the stability. @*Materials and Methods@#This was a retrospective single-center study. The consecutive patients who had a PS-PMMA+SAR for a DM from OVCF and were followed up more than two years were reviewed. Thirty patients were eligible for this study. All patients used fenestrated screws for PMMA augmentation. Anterior reinforcement was selected according to the stability. The unstable type was done by filling the vacuum cleft with bone chips or PMMA, and the stable type was done by vertebral body anterior translation with/without an interbody bone graft. The radiological and functional outcomes were evaluated. @*Results@#There were 20 unstable and 10 stable cases. The regional kyphotic angle was improved significantly from 31.3°±10.8° to 10.4°±8.3° (p<0.001). The anterior vertebral height ratio was improved significantly from 39.4%±17.1% to 86.4%±9.2% (p<0.001). The spinal canal invasion ratio was improved significantly from 39.2%±14.8% to 19.1%±10.8% (p<0.001). The walking ability was improved mostly by two Nurick’s grades (p<0.001). The Oswestry disability index was improved from 72% to 33% (p<0.001). @*Conclusion@#Posterior surgery with PMMA-augmented pedicle screws, and selective anterior reinforcement for DM from OVCF was available to achieve a good functional and radiological outcome.

Comparison of Fusion Rate between Demineralized Bone Matrix versus Autograft in Lumbar Fusion : Meta-Analysis

The demineralized bone matrix (DBM) as the bone graft material to increase the fusion rate was widely used in spinal fusion. The current study aimed to compare the fusion rate of DBM to the fusion rate of autograft in lumbar spine fusion via meta-analysis of published literature. After systematic search, comparative studies were selected according to eligibility criteria. Checklist (risk of bias assessment tool for non-randomized study) was used to evaluate the risk of bias of the included nonrandomized controlled studies. The corresponding 95% confidence interval (95% CI) were calculated. We also used subgroup analysis to analyze the fusion rate of posterolateral lumbar fusion and lumbar interbody fusion. Eight studies were finally included in this meta-analysis. These eight studies included 581 patients. Among them, 337 patients underwent spinal fusion surgery using DBM (DBM group) and 204 patients underwent spinal fusion surgery with mainly autologous bone and without using DBM (control group). There was no significant differences of fusion rate between the two groups in posterolateral fusion analysis (risk ratio [RR], 1.03; 95% CI, 0.90–1.17; p=0.66) and interbody fusion analysis (RR, 1.13; 95% CI, 0.91–1.39; p=0.27). Based on the available evidence, the use of DBM with autograft in posterolateral lumbar spine fusion and lumbar interbody fusion showed a slightly higher fusion rate than that of autograft alone; however, there was no statistically different between two groups.

Clinical Effects and Complications of Pedicle Screw Augmentation with Bone Cement: Comparison of Fenestrated Screw Augmentation and Vertebroplasty Augmentation

Background@#Pedicle screw augmentation with bone cement has been experimentally demonstrated to increase the pullout strength. However, the mechanisms of screw loosening are complicated and interacting. Although vertebroplasty augmentation and fenestrated screw augmentation have been compared in many studies, there has been no comparative study on their clinical effects and complications in real clinical settings. We investigated clinical effects of bone cement augmentation of a pedicle screw and differences according to augmentation methods. @*Methods@#Of the total 241 patients who had osteoporosis and underwent posterior pedicle screw fixation without anterior bone graft between January 2010 and December 2016, 132 patients with ≥2 years of radiological follow-up were included in this retrospective study. The patients were divided into group I (unaugmented) and group II (bone cement augmented). Group II was subdivided into II-S group (solid screw augmented) and II-F group (fenestrated screw augmented). The incidence of screw loosening was compared between groups I and II. Cement leakage, screw loosening, and screw fractures were investigated in the subgroups. @*Results@#In total, 36 of 71 (52%, group I) unaugmented cases and 96 of 170 (56%, group II) augmented cases were followed up for ≥2 years. Of the total 78 solid screw augmented cases, 42 (56%) were in II-S group; 54 of the total 92 (59%) fenestrated screw augmented cases were in II-F group. Groups I and II were homogenous regarding demographic characteristics; II-S and II-F groups were also homogenous. The incidence of screw loosening was 50.0% (18/36) in group I and 7.3% (7/96) in group II (p < 0.001). Cement leakage developed in 2 of 42 (4.8%) cases in II-S group and in 5 of 54 (9.3%) cases in II-F group (p = 0.462). Screw loosening developed in 6 of 42 (14.3%) cases in II-S group and in 1 of 54 cases (1.9%) in II-F group (p = 0.041). Screw fracture developed in none of 42 cases in II-S group and in 3 of 54 cases (5.6%) in II-F group (p = 0.254). @*Conclusions@#In osteoporotic patients, bone cement augmentation of a pedicle screw decreased the incidence of screw loosening, and fenestrated screw augmentation was more effective than vertebroplasty augmentation.

Vertebral Body Anterior Translation, a Novel Technique for Delayed Myelopathy Due to Osteoporotic Spine Fractures

Background@#Osteoporotic vertebral compression fractures (OVCFs) are often associated with delayed myelopathy. Surgical treatment of delayed myelopathy following an OVCF comprises spinal canal decompression and stable fixation of the vertebral column with an acceptable sagittal alignment. However, such surgical methods are not usually feasible because of medical comorbidities and osteoporosis. We devised a novel, simple technique to decompress the spinal canal and reconstruct the middle column by translating the fractured vertebral body anteriorly through a posterior approach and verified the validity of the new technique. @*Methods@#We conducted a single-center, retrospective study. Patients who underwent vertebral body anterior translation (VBaT) between 2014 and 2017 due to delayed myelopathy after OVCFs were included. Through a posterior approach, discs between the fractured vertebra and the adjacent vertebrae were released. The fractured vertebra was translated anteriorly with pedicle screws and rods to realign the middle column. Radiological and functional improvement was analyzed. @*Results@#There were 12 consecutive patients. The mean age was 70.3 ± 9.4 years. There were 8 female and 4 male patients. Follow-up period was 35.9 ± 13.1 months. Nine patients had pedicle screw augmentation with polymethyl methacrylate. The mean number of fusion segments was 3.4 (range, 2–4). There were 3 types of spinal canal invasion. Five patients had vertebral body vacuum clefts with posterior wall fractures. Five patients had vertebral body angulation with endplate protrusion. Two patients had 3 column fractures. In radiological analysis, the regional kyphotic angle was 35.1° ± 9.1° preoperatively and improved to 8.8° ± 6.8° postoperatively and 9.8° ± 6.1° at the final follow-up (p < 0.001). The anterior vertebral body height ratio was 27.6% ± 7.0% preoperatively and improved to 80.5% ± 13.7% postoperatively and 83.7% ± 12.5% at the final follow-up (p < 0.001). The spinal canal invasion ratio was 52.6% ± 9.1% preoperatively and improved to 25.2% ± 10.4% postoperatively (p < 0.001). Neurological deficit was improved in all patients by 1–3 grades according to Nurick’s grading system. @*Conclusions@#In delayed myelopathy following an OVCF, although the posterior cortex invades the spinal canal, it is usually already in the union state. Therefore, it can bear compression force as a middle column if realigned to be in line with the adjoining vertebrae. VBaT demonstrated satisfactory reduction of kyphosis and maintenance of stability until the last follow-up.

Influence of Epidural Steroid Injection on Adrenal Function

BACKGROUND: Spinal diseases are self-limited or non-progressive in many cases. Epidural steroid injection (ESI) is a common nonsurgical treatment option for spinal pain. Despite concerns about complications of repeated steroid injection, few studies reported on the adrenal function of spine disease patients undergoing surgery after ESI. We investigated the influence of preoperative multiple ESIs on adrenal function in spine surgery patients. METHODS: This was a retrospective study with prospective data collection. Those who underwent elective spinal operations and had a history of multiple ESIs from January to June 2017 were selected as a study group. Those who underwent knee arthroplasty and did not have a history of ESI and any kind of steroid injection in other areas during 6 months before surgery were selected as a control group. Demographic data were compared to assess homogeneity between groups. We assessed the preoperative serum cortisol level (SCL) to compare the basal adrenal function between groups. Also, we assessed the elevation of SCL postoperatively to evaluate the adrenal response to the surgical stress in each group. For subgroup analysis, we divided all patients into normal (7–28 µg/dL) and subnormal groups according to SCL and analyzed risk factors of adrenal suppression with multivariate logistic regression test. RESULTS: There were 53 patients in the study group and 130 in the control group. Age and sex were homogeneous between groups. There was significant intergroup difference in preoperative SCL (10.4 ± 4.8 µg/dL in the study group vs. 12.0 ± 4.2 µg/dL in the control group; p = 0.026).The postoperative day one SCL was 11.6 ± 5.0 µg/dL in the study group without significant increase from the preoperative level (p = 0.117), whereas the increase was significant in the control group with a postoperative level of 14.4 ± 4.4 µg/dL (p < 0.001). Among all patients, the SCL was subnormal in 18 patients and within the normal range in 165. Spine surgery was the independent risk factor irrespective of age and sex (odds ratio, 3.472; p = 0.015). CONCLUSIONS: Our results suggest that concern should be raised about the influence of preoperative multiple ESIs on adrenal suppression in spine surgery patients.

The Evidence for Nonoperative Treatment of Lumbar Spinal Diseases

OBJECTIVES@#To assess the evidence for nonoperative treatment of various degenerative spinal degenerative diseases.SUMMARY OF LITERATURE REVIEW: No study has yet evaluated the evidence for preoperative nonoperative treatment of lumbar spinal diseases.@*METHODS@#The evidence regarding nonoperative treatment for each disease was reviewed through NASS guidelines, and the treatment effect compared to surgical treatment was reviewed through the SPORT series. The efficacy of nonoperative treatment according to disease severity and certain special conditions was investigated through corresponding individual articles.@*RESULTS@#No kind of nonoperative treatment could change the fundamental progression of degenerative spinal disease. The natural course of lumbar disc herniation is favorable regardless of treatment. More than 70% of routine cases improve within 6 weeks. However, it does not take a full 6 weeks to decide whether to perform surgery or not. The evidence for transforaminal epidural steroid injections for short-term pain control is grade A. There is grade B evidence for nonoperative treatment with the goal of mid- to long-term pain control. However, we cannot say that those outcomes are better than the natural course of the disease itself. In cases of radicular weakness, the degree of weakness is correlated with the final outcomes, but it is not evident whether the duration of weakness is correlated with surgical outcomes. Early surgery is usually necessary due to intolerable pain, rather than stable motor weakness. The social cost of herniated discs arises from the loss of patients’ productivity, rather than from direct medical expenses. The natural course of spinal stenosis involves provoked pain and the need for palliative care. Unlike disc herniation, rapid deterioration and marked improvement do not occur. The symptoms of mild to moderate lumbar stenosis are unchanged in 70% of cases, improve in 15%, and worsen in 15%. No study has compared nonoperative treatment with the natural course of the disease. There is no evidence for nonoperative treatment of severe stenosis. Epidural spinal injections are effective for controlling short-term pain. Spontaneous recovery of radicular weakness does not occur, and urgent surgery is necessary in such cases. There is no evidence regarding the natural course and nonoperative treatment of degenerative spondylolisthesis. The working group consensus recommends that it should follow the pattern of nonoperative treatment of spinal stenosis when radicular stenosis symptoms are predominant. Overall, 40%–66% of cases of adult bilateral isthmic spondylolysis progress to symptomatic spondylolisthesis. No studies have investigated nonoperative treatment except physical exercise.@*CONCLUSIONS@#Although short-term symptom amelioration can be achieved by nonoperative treatment, the fundamental progression of the disease is not affected. For conditions excluded from most studies, such as prior spine surgery, cauda equina syndrome, progressive neurological deficit, and uncontrollable severe pain associated with instability, deformity, or vertebral fractures, there were not enough studies to reach informed conclusions. Our review found no evidence regarding nonoperative treatment for such conditions. Furthermore, the treatment methods for each disease are not clearly distinguished from each other, and the techniques used for disc herniation have been applied to other diseases without any evidence.

The Evidence for Nonoperative Treatment of Lumbar Spinal Diseases / 대한척추외과학회지

STUDY DESIGN: Review article.OBJECTIVES: To assess the evidence for nonoperative treatment of various degenerative spinal degenerative diseases.SUMMARY OF LITERATURE REVIEW: No study has yet evaluated the evidence for preoperative nonoperative treatment of lumbar spinal diseases.METHODS: The evidence regarding nonoperative treatment for each disease was reviewed through NASS guidelines, and the treatment effect compared to surgical treatment was reviewed through the SPORT series. The efficacy of nonoperative treatment according to disease severity and certain special conditions was investigated through corresponding individual articles.RESULTS: No kind of nonoperative treatment could change the fundamental progression of degenerative spinal disease. The natural course of lumbar disc herniation is favorable regardless of treatment. More than 70% of routine cases improve within 6 weeks. However, it does not take a full 6 weeks to decide whether to perform surgery or not. The evidence for transforaminal epidural steroid injections for short-term pain control is grade A. There is grade B evidence for nonoperative treatment with the goal of mid- to long-term pain control. However, we cannot say that those outcomes are better than the natural course of the disease itself. In cases of radicular weakness, the degree of weakness is correlated with the final outcomes, but it is not evident whether the duration of weakness is correlated with surgical outcomes. Early surgery is usually necessary due to intolerable pain, rather than stable motor weakness. The social cost of herniated discs arises from the loss of patients’ productivity, rather than from direct medical expenses. The natural course of spinal stenosis involves provoked pain and the need for palliative care. Unlike disc herniation, rapid deterioration and marked improvement do not occur. The symptoms of mild to moderate lumbar stenosis are unchanged in 70% of cases, improve in 15%, and worsen in 15%. No study has compared nonoperative treatment with the natural course of the disease. There is no evidence for nonoperative treatment of severe stenosis. Epidural spinal injections are effective for controlling short-term pain. Spontaneous recovery of radicular weakness does not occur, and urgent surgery is necessary in such cases. There is no evidence regarding the natural course and nonoperative treatment of degenerative spondylolisthesis. The working group consensus recommends that it should follow the pattern of nonoperative treatment of spinal stenosis when radicular stenosis symptoms are predominant. Overall, 40%–66% of cases of adult bilateral isthmic spondylolysis progress to symptomatic spondylolisthesis. No studies have investigated nonoperative treatment except physical exercise.CONCLUSIONS: Although short-term symptom amelioration can be achieved by nonoperative treatment, the fundamental progression of the disease is not affected. For conditions excluded from most studies, such as prior spine surgery, cauda equina syndrome, progressive neurological deficit, and uncontrollable severe pain associated with instability, deformity, or vertebral fractures, there were not enough studies to reach informed conclusions. Our review found no evidence regarding nonoperative treatment for such conditions. Furthermore, the treatment methods for each disease are not clearly distinguished from each other, and the techniques used for disc herniation have been applied to other diseases without any evidence.

The Influence of Antiplatelet Drug Medication on Spine Surgery

BACKGROUND: The incidence of cardiovascular and neurovascular diseases has been increasing with the aging of the population, and antiplatelet drugs (APDs) are more frequently used than in the past. With the average age of spinal surgery patients also increasing, there has been a great concern on the adverse effects of APD on spine surgery. To our knowledge, though there have been many studies on this issue, their results are conflicting. In this study, we aimed to determine the influence of APDs on spine surgery in terms of intraoperative bleeding and postoperative spinal epidural hematoma complication. METHODS: Patients who underwent posterior thoracolumbar decompression and instrumentation at our institution were reviewed. There were 34 APD takers (APDT group). Seventy-nine non-APD takers (NAPDT group) were selected as a control group in consideration of demographic and surgical factors. There were two primary endpoints of this study: the amount of bleeding per 10 minutes and cauda equina compression by epidural hematoma measured at the cross-sectional area of the thecal sac in the maximal compression site on the axial T2 magnetic resonance imaging scans taken on day 7. RESULTS: Both groups were homogeneous regarding age and sex (demographic factors), the number of fused segments, operation time, and primary/revision operation (surgical factors), and the number of platelets, prothrombin time, and activated partial thromboplastin time (coagulation-related factors). However, the platelet function analysis-epinephrine was delayed in the APDT group than in the NAPDT group (203.6 seconds vs. 170.0 seconds, p = 0.050). Intraoperative bleeding per 10 minutes was 40.6 ± 12.8 mL in the APDT group and 43.9 ± 9.9 mL in the NAPDT group, showing no significant difference between the two groups (p = 0.154). The cross-sectional area of the thecal sac at the maximal compression site by epidural hematoma was 120.2 ± 48.2 mm2 in the APDT group and 123.2 ± 50.4 mm2 in the NAPDT group, showing no significant difference between the two groups (p = 0.766). CONCLUSIONS: APD medication did not increase intraoperative bleeding and postoperative spinal epidural hematoma. Therefore, it would be safer to perform spinal surgery without discontinuation of APD therapy in patients who are vulnerable to cardiovascular and neurovascular complications.

Spinal Subarachnoid Hematoma after Spinal Anesthesia: A Case Report

OBJECTIVES@#We report a case of spinal subarachnoid hematoma that developed after spinal anesthesia in a female patient who had no risk factors.SUMMARY OF LITERATURE REVIEW: Few case reports of spinal subarachnoid hematoma (SSH) after spinal anesthesia have been published. The incidence of SSH is much less than that of epidural hematoma.@*MATERIALS AND METHODS@#A 56-year-old female patient underwent arthroscopic surgery on her right knee under spinal anesthesia. Automated patient-controlled analgesia (PCA) was applied after surgery. On day 2, the patient complained of lower back pain, headache, nausea, and vomiting, but there were no neurological signs in the lower extremity. At day 5, she had a moderate fever (38.4°) and continuous nausea and vomiting. Magnetic resonance imaging (MRI) was conducted on day 5 and a large subarachnoid hematoma was found. We immediately performed surgical hematoma evacuation. Her low back and buttock pain improved immediately, and all symptoms disappeared in a week without any neurological sequelae.@*RESULTS@#The unusual and vague symptoms in this case made the diagnosis difficult, but spinal MRI confirmed SSH. Immediate surgical hematoma evacuation improved all symptoms and left no neurologic sequelae.@*CONCLUSIONS@#SSH after spinal anesthesia may have cerebral symptoms that mimic the side effects of PCA. Early diagnosis by MRI and surgical evacuation of the SSH are a reasonable approach for this complication.

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.

Spinal Subarachnoid Hematoma after Spinal Anesthesia: A Case Report / 대한척추외과학회지

STUDY DESIGN: Case report. OBJECTIVES: We report a case of spinal subarachnoid hematoma that developed after spinal anesthesia in a female patient who had no risk factors. SUMMARY OF LITERATURE REVIEW: Few case reports of spinal subarachnoid hematoma (SSH) after spinal anesthesia have been published. The incidence of SSH is much less than that of epidural hematoma. MATERIALS AND METHODS: A 56-year-old female patient underwent arthroscopic surgery on her right knee under spinal anesthesia. Automated patient-controlled analgesia (PCA) was applied after surgery. On day 2, the patient complained of lower back pain, headache, nausea, and vomiting, but there were no neurological signs in the lower extremity. At day 5, she had a moderate fever (38.4°) and continuous nausea and vomiting. Magnetic resonance imaging (MRI) was conducted on day 5 and a large subarachnoid hematoma was found. We immediately performed surgical hematoma evacuation. Her low back and buttock pain improved immediately, and all symptoms disappeared in a week without any neurological sequelae. RESULTS: The unusual and vague symptoms in this case made the diagnosis difficult, but spinal MRI confirmed SSH. Immediate surgical hematoma evacuation improved all symptoms and left no neurologic sequelae. CONCLUSIONS: SSH after spinal anesthesia may have cerebral symptoms that mimic the side effects of PCA. Early diagnosis by MRI and surgical evacuation of the SSH are a reasonable approach for this complication.

Neurological Complications of Posterior Spinal Surgery: Incidence and Clinical Features / 대한척추외과학회지

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.

Prognostic Factors of Neurological Complications in Spinal Surgeries

STUDY DESIGN: Retrospective study. PURPOSE: To determine prognostic factors of neurological complications (NCs) of posterior thoracolumbar surgeries. OVERVIEW OF LITERATURE: There have been few reports on the prognosis of NCs according to the causes and treatment methods. METHODS: The subjects were 65 patients who had NCs for 19 years (1995–2013) after posterior thoracolumbar surgeries in Seoul Sacred Heart General Hospital. The degree of neurological injury was assessed using numeric scales as follows: G1, increased leg pain or sensory loss; G2, hemiparesis; G3, paraparesis; G4, cauda equine syndrome; and G5, complete paraplegia. The relative degree of neurological recovery was evaluated using four numeric scales as follows: Gr1, complete recovery; Gr2, almost complete recovery with residual sensory loss or numbness; Gr3, partial recovery with apparent neurological deficit; and Gr4, no recovery. The prognostic factors were investigated in terms of demographic and surgical variables that were available in a retrospective review. RESULTS: The causes were as follows: epidural hematoma (EH), 25 patients (38.5%); insufficient decompression and fusion, 14 patients (21.5%); mechanical injury, 11 patients (16.9%); insufficient discectomy, four patients (6.2%); and unknown, 11 patients (23.1%). The grade of neurological injury was as follows: G1, 11 patients (16.9%); G2, 34 patients (52.3%); G3, 15 patients (23.1%); G4, three patients (4.6%); and G5, two patients (3.1%). Thirteen patients received conservative treatment, and 52 underwent revision surgeries. Neurological recovery was as follows: Gr1, 21 patients (32.3%); Gr2, 17 patients (26.2%); Gr3, 20 patients (30.8%); and Gr4, seven patients (10.8%). The prognosis depended on the causes (p =0.041). The subgroup analysis of the revision group revealed a significant correlation between the degree of neurological recovery and the timing of revision, irrespective of causes (r =0.413, p =0.002). CONCLUSIONS: The prognosis of NC depended on the causes. EH was the best and unknown was the worst prognostic factor. Revision should be performed as soon as possible for a better prognosis.

Analgesic Effects of Antiosteoporotic Drugs

STUDY DESIGN: Literature review. OBJECTIVES: To propose possible mechanisms of osteoporotic back pain and its management with antiosteoporotic drugs. SUMMARY OF LITERATURE REVIEW: No general conclusion has yet been reached regarding whether osteoporosis without fractures can cause pain. Instead, only treatments for back pain without osteoporotic spine fractures have been reviewed in the previous literature. Although key studies of antiosteoporotic drugs have not investigated their analgesic efficacy, plausible mechanisms have been suggested. MATERIALS AND METHODS: The analgesic effects of antiosteoporotic agents available in Korea were reviewed. RESULTS: Rather than the long-term use of conventional analgesics or narcotics, antiosteoporotic drugs would be more beneficial because they can enhance bone strength and have fewer side effects. Both anabolic and antiresorptive agents available in Korea have been proven to have an analgesic effect against osteoporotic back pain, with or without fractures. Anabolic agents depend on skeletal effects. Among antiresorptive agents, bisphosphonates have both skeletal and extraskeletal mechanisms for analgesia. Calcitonin and selective estrogen receptor modulators mostly depend on extraskeletal effects. The order of analgesic strength for osteoporotic back pain is teriparatide > bisphosphonate > calcitonin. This implies that the analgesic effect of antiosteoporotic drugs primarily depends on their skeletal effects rather than on their extraskeletal effects. Moreover, because non-fracture osteoporotic pain has been recognized only in the spine, where fractures can occur without a sensible injury, pain may arise from undiscovered spine fractures. CONCLUSIONS: Antiosteoporotic drugs ameliorate osteoporotic back pain. Their analgesic strength is proportional to their fracture prevention efficacy.

Postoperative Spinal Epidural Hematoma: The Danger Caused by the Misuse of Thrombin-Containing Local Hemostatics

STUDY DESIGN: Retrospective case-control study. PURPOSE: To examine the hypothesis that the misuse of thrombin-containing local hemostatics (TCLH) increases the risk of postoperative spinal epidural hematoma (POSEH). OVERVIEW OF LITERATURE: Many studies have focused on hypocoagulability as a risk factor for POSEH. However, there are no prior reports on the increased risk of POSEH in hypercoagulable states. METHODS: Posterior instrumented lumbar spine surgery cases over 2 consecutive years were divided into two groups: a study group (98 patients in whom TCLH was used) and a control group (176 patients in whom TCLH was not used). The excess TCLH matrix that was not associated with blood clot was not removed from the patients in the study group. The senior author decided whether to use TCLH or not. Suction drains were used in all patients. The demographics, coagulation-related factors, and intraoperative factors of the patients in the two groups were analyzed. The development of POSEH was compared between the two groups. RESULTS: The two groups were homogenous in demographics (age and sex), coagulation-related factors (platelet count, prothrombin time, activated partial thromboplastin time, and platelet function analysis), and surgical factors (total blood loss, operation time, blood loss/10 minutes, number of fusion segments, posterolateral fusion/posterior lumbar interbody fusion, and virgin or revision surgery). POSEH developed more frequently in the patients in the study group than in those in the control group (14/98 patients, 14.3% vs. 3/176 patients, 1.7%, respectively; p=0.001; odds ratio, 17.1). CONCLUSIONS: TCLH causes blood clot not only at the edge of damaged vessels but also at the site of extravascular blood. Excess TCLH matrix not associated with blood clot at the epidural space can enhance POSEH development because early clotted hematomas do not drain through suction drains.

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.

Can We Prevent a Postoperative Spinal Epidural Hematoma by Using Larger Diameter Suction Drains?

BACKGROUND: Epidural hematoma is a rare but serious complication. According to previous studies, it is not prevented by suction drains. This study evaluated the following alternative hypothesis: the larger the diameter of a suction drain, the less the remaining epidural hematoma after spinal surgery. METHODS: This was a randomized prospective study. Patients who underwent posterior lumbar decompression and instrumented fusion were divided into two groups: the large drain (LD, 2.8-mm-diameter tube) and small drain (SD, 1.6-mm-diameter tube) groups according to the diameter of the suction drains. All patients were consecutive and allocated alternately according to the date of operations. Suction drains were removed on day 3 and magnetic resonance imaging was performed on day 7 postoperatively. The size of remaining hematomas was measured by the degree of thecal sac compression in cross section using the following 4-point numeric scale: G1, less than one quarter; G2, between one quarter and half; G3, more than half; and G4, more than subtotal obstruction. RESULTS: There were 39 patients with LDs and 38 with SDs. They did not differ significantly in terms of sex, number of fusion segments, revision or not, antiplatelet medication, intraoperative injection of tranexamic acid. However, patient age differed significantly between the two groups (LD, 63.3 years and < SD, 68.6 years; p = 0.007). The two groups did not differ significantly in terms of prothrombin time, activated partial thromboplastin time, platelet number, blood loss, or operation duration. However, platelet function analysis exhibited a significant difference (LD, 164.7 seconds and < SD, 222.3 seconds; p = 0.002). The two blinded readers showed high consistency (Kappa value = 0.740; p = 0.000). The results of reader 1 were as follows: LD and SD had 21 and 21 cases of G1, 9 and 11 cases of G2, 6 and 6 cases of G3, and 3 and 0 cases of G4, respectively. The results of reader 2 were as follows: LD and SD had 22 and 23 cases of G1, 7 and 9 cases of G2, 7 and 6 cases of G3, and 3 and 0 cases of G4, respectively. There was no difference between the two groups (reader 1, p = 0.636; reader 2, p = 0.466). CONCLUSIONS: The alternative hypothesis was rejected. Therefore, postoperative spinal epidural hematoma would not be prevented by LD.

Treatment of Surgical Site Infection in Posterior Lumbar Interbody Fusion

STUDY DESIGN: A retrospective observational and case control study. PURPOSE: To identify appropriate treatment options according to the types of surgical site infections (SSI) in instrumented posterior lumbar interbody fusion (PLIF). OVERVIEW OF LITERATURE: There has been no agreement or consensus with regard to this matter. METHODS: Thirty-two consecutive SSIs were included and followed for more than one year. The elapsed time to diagnosis (ETD) according to the type of SSI was analyzed. The treatment options for each type and consequent clinical results were reviewed. The risk factors of removing the implants were analyzed. RESULTS: There were 6/32 (19%) superficial incisional, 6/32 (19%) deep incisional, and 20/32 (62%) organ/space infection cases (SII, DII, and O/SI, respectively) (p=0.002). ETD was 8.5+/-2.3 days in SII, 8.7+/-2.3 days in DII, and 164.5+/-131.1 days in O/SI (p=0.013). All cases of SII and DII retained implants and were treated by repeated irrigation and secondary closure. Among O/SIs, 10/20 were treated conservatively. Nine out of ten underwent posterior one stage simultaneous revision (POSSR) and in one case, the cage was removed anteriorly. Those who had ETDs longer than 3 months showed a significant risk of implant removal (p=0.008, odds ratio [OR]=40.3). The Oswestry disability index (ODI) improved from 47.3% to 33.8% in SII, from 55.0% to 32.3% in DII, and from 53.4% to 42.1% in O/SI (p=0.002). There was no difference among the three groups (p=0.106); however, there was a partial correlation between ETD and final ODI (r=0.382, p=0.034). CONCLUSIONS: Latent O/SI was the most common type of SSI in PLIF. In cases of SII and DII, early aggressive wound management and secondary closure was effective and implant removal was not necessary. In some cases of O/SI, implant removal was unavoidable. However, implant removal could be averted by an earlier diagnosis. POSSR was feasible and safe. Functional outcomes were improved; however, disability increased as ETD increased.

Hemophilia A in a Senior Patient: A Case Report of Spinal Epidural Hematoma as First Presentation

Hemophilia A is a hereditary coagulation disorder. Most cases are diagnosed at birth or at least during childhood. A spontaneous spinal epidural hematoma was developed in a 74-year-old male patient who hadn't had a family or past medical history of bleeding disorders. On magnetic resonance imaging, epidural hematoma at L1-2 was accompanied by spinal stenosis at L4-5 and spondylolytic spondylolisthesis at L5. Hematoma evacuation and surgery for distal lumbar lesions were performed at once. After transient improvement, complete paraplegia was developed due to redevelopment of large epidural hematomas at L1-2 and L4-S1 which blocked epidural canal completely. Emergency evacuation was performed and we got to know that he had a hemophilia A. Factor VIII was 28% of normal value. Mild type hemophilia A could have not been diagnosed until adulthood. Factor VIII should have been replaced before the surgical decompression.