Effect of Thrombin-Containing Local Hemostatics on Postoperative Spinal Epidural Hematoma in Biportal Endoscopic Spinal Surgery.

STUDY DESIGN: Retrospective case-control study. PURPOSE: This study aimed to investigate the preventive effect of thrombin-containing local hemostatics (TCLH) on postoperative spinal epidural hematoma (POSEH) in biportal endoscopic spinal surgery (BESS). This study compared the incidence of morphometric and symptomatic POSEH with or without TCLH in BESS. OVERVIEW OF LITERATURE: POSEH is reported not uncommon in BESS when compared with conventional spine surgery (CSS). TCLH achieves hemostasis with a high success rate in CSS. However, few studies have examined the effect of TCLH on BESS. METHODS: Patients with and without TCLH were assigned to groups A and B, respectively. POSEH between the two groups was compared morphometrically and symptomatically. The risk factors for symptomatic and morphometric POSEH in BESS were identified. RESULTS: The morphometric POSEH was greater in group B, and the difference was significant (p =0.019). The incidence of symptomatic POSEH was lower in group A with 4.6% (5/109) than in group B with 9.5% (9/95); however, the rate was not significantly different (p =0.136). The morphometric POSEH was classified into two small (hG1 and hG2) and large (hG3 and hG4) and were compared between groups A and B, and the difference was significant (p =0.02). In the multivariable logistic regression, nonuse of TCLH (p =0.004) and preoperative diagnosis of stenosis (p =0.016) were variables found to be significant risk factors of morphometric POSEH. CONCLUSIONS: Severe compression of the thecal sac by POSEH is more common in patients without TCLH. The risk of hematoma formation was higher when bilateral decompression was needed and the cut bone surface was more exposed.

Treatment Concept and Technical Considerations of Biportal Endoscopic Spine Surgery for Lumbar Spinal Stenosis.

Decompression is a major component of surgical procedures for degenerative lumbar spinal stenosis (LSS). In addition to sufficient decompression to guarantee the relief of neurological pain, compensating surgical instability after wider laminectomy and foraminotomy and instrumentation with caging and fusion with grafting are performed to secure or restore the foraminal dimension and correct coronal/sagittal imbalance for longer survival of the adjacent segment. Endoscopic spinal surgery (ESS) has been developed under the flag of successful decompression while preserving structural integrity as much as possible with the help of magnification and illumination. ESS provides a technical possibility and feasibility for solving LSS by decompression alone. Recently, many endoscopic trials have been conducted to overcome conventional surgical treatment that requires wider dissection, escape inevitable complications from surgical damage, and compensate for the fusion technique. However, biportal ESS has some technical limitations, including clinical difficulties in accessibility for more moderate to severe stenosis and challenges for complicated conditions with segmental ventral slip, isthmic defect, stenosis combined with foraminal stenosis or foraminal disk rupture, or degenerative segmental scoliosis with disk height collapsing and endplate fatigue fracture. Because decompression alone is a skill for eliminating pathologies, there is no function of preserving degenerative structure or stopping the recurrence of disk degeneration or subsidence. This review of clinical reports investigated the possibility of biportal ESS for treating degenerative lumbar disorders by sufficient decompression and adequate elimination of various pathologies and decreasing technical complications. The results of this study may help develop better innovative spinal surgical techniques in the near future.

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.

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

[This corrects the article on p. 485 in vol. 12, PMID: 33274026.].

Postoperative spinal epidural hematoma in a biportal endoscopic spine surgery.

ABSTRACT: Biportal endoscopic spine surgery (BESS) is extending its application to most kind of spine surgeries. Postoperative spinal epidural hematoma (POSEH) is one of the major concerns of this emerging technique. Through this study we aim to investigate the incidence of POSEH in BESS comparing to a conventional spine surgery (CSS).The patients who underwent a non-fusion decompressive spine surgery due to degenerative lumbar spinal stenosis (LSS) or herniated lumbar disc (HLD) or both between January 2015 and March 2019 were reviewed retrospectively. The incidence of clinical POSEH that demanded a revision surgery for hematoma evacuation was compared between CSS and BESS. As a second endpoint, the morphometric degree of POSEH was compared between the two groups. The maximal compression of cauda equina by POSEH was measured by 4 grade scale at the T2 axial image and the neurological state was evaluated by 5 grade scale. The indication of hematoma evacuation was more than hG3 with more than nG1. As a subgroup analysis, risk factors of POSEH in BESS were investigated.The 2 groups were homogenous in age, sex, number and level of operated segments. There was significant difference in the incidence of symptomatic POSEH as 2/142 (1.4%) in CSS and 8/95 (8.4%) in BESS (P = .016). The radiological thecal sac compression by hematoma was hG1 65 (61.3%), hG2 35 (33.0%), hG3 5 (4.7%), hG4 1 (0.9%) cases in CSS and hG1 33 (39.8%), hG2 25 (30.1%), hG3 22 (26.5%), hG4 3 cases (3.6%) in BESS. The difference was significant (P < .001). In BESS subgroup analysis, the risk factor of high grade POSEH was bilateral laminectomy (OR = 8.893, P = .023).The incidence of clinical and morphometric POSEH was higher in BESS. In BESS, POSEH developed more frequently in bilateral laminectomy than unilateral laminectomy.

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

BACKGROUD: 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.

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.

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.

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 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.

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.

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.

Bulb Syringe and Pulsed Irrigation: Which Is More Effective to Remove Bacteria in Spine Surgeries?

STUDY DESIGN: Retrospective study. OBJECTIVES: The aim of this study was to investigate the difference of efficacy between bulb syringe irrigation and pulsed irrigation in spinal surgeries. SUMMARY OF BACKGROUND: Pulsed irrigation has been used for more than half a century, especially in trauma surgeries. However, to the best of our knowledge, there has been no study as to the efficacy of pulsed irrigation in spinal surgeries so far. MATERIALS AND METHODS: The consecutive patients who underwent posterior lumbar interbody fusion for 6 months were investigated. Those who underwent surgeries during the first 3 months were irrigated by bulb syringe (group I) and those who underwent surgeries during the next 3 months were irrigated by pulsatile irrigator with 17 psi (group II). Sex, age, surgery time, amount of blood loss, whether associated with diabetes mellitus, smoking, and amount of irrigation solution were compared between the 2 groups to identify homogeneity. Normal saline was used. Intraoperative irrigations were performed 3 times as time elapsed. After the last irrigation, culture specimens were obtained from the muscle layer and intervertebral space. The culture results were compared between the 2 groups. RESULTS: There were 79 cases in group I and 59 cases in group II. In the homogeneity test, surgery time was longer (P=0.011) and amount of irrigation saline was larger (P=0.042) in group II. From the posterior muscle layer, bacteria were cultured in 8/79 cases (10.1%) in group I and 1/59 cases (1.6%) in group II. There was a significant difference between the 2 groups (P=0.046). And from the intervertebral space, it was cultured in 6/79 cases (7.6%) in group I and 5/59 cases (8.5%) in group II. There was no difference between the 2 groups (P=0.546). Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus hominis, and Staphylococcus saprophyticus were cultured in order of the frequency. CONCLUSIONS: Pulsed irrigation was more effective compared with bulb syringe irrigation in the posterior muscle layer. In the intervertebral space, however, both methods were insufficient to eradicate contaminated bacteria.

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.

Particular Features of Surgical Site Infection in Posterior Lumbar Interbody Fusion.

BACKGROUND: Previous reports have observed differences only in infection rates between posterolateral fusion and posterior lumbar interbody fusion (PLIF). There have been no reports that describe the particular features of surgical site infection (SSI) in PLIF. In this study, we endeavor to identify the distinguishing characteristics and risk factors of SSI in PLIF. METHODS: Our study undertook a review of a case series of an institute. Patients who had undergone PLIF consecutively in the author's hospital were reviewed. Two proactive procedures were introduced during the study period. One was irrigation of the autolocal bone, and the other was the intradiscal space irrigation with a nozzle. Infection rate and risk factors were analyzed. For subgroup analysis, the elapsed time to a diagnosis (ETD), clinical manifestations, hematologic findings, and causative bacteria were examined in patients with SSI. RESULTS: In a total of 1,831 cases, there were 30 cases of SSI (1.6%). Long operation time was an independent risk factor (p = 0.008), and local bone irrigation was an independent protective factor (p = 0.001). Two cases of referred SSI were included in the subgroup analysis. There were 6/32 (19%) superficial incisional infections (SII), 6/32 (19%) deep incisional infections (DII), and 20/32 (62%) organ/space infections (O/SI). The difference of incidence among three groups was significant (p = 0.002).The most common bacteria encountered were methicillin-resistant Staphylococcus epidermidis followed by methicillin-resistant S. aureus in incisional infections, and no growth followed by S. epidermidis in O/SI. 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). CONCLUSIONS: The rate of SSI in PLIF was 1.6%, with the most common type being O/SI. The causative bacteria of O/SI was of lower virulence than in the incisional infection, and thus diagnosis was delayed due to its latent and insidious feature. Contamination of auto-local bone was presumed attributable to the progression of SSI. Irrigation of auto-local bone helped in the reduction of SSI.

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.

Bilateral Femoral Neck Insufficiency Fractures after Use of a Long-term Anti-resorptive Drug Therapy for Osteoporosis: A Case Report.

A 78-year-old woman developed an insufficiency fracture on her right femoral neck without trauma after four years of treatment with a bisphosphonate. Her fracture was fixed by two screws and her anti-osteoporotic drug was changed from an anti-resorptive to an anabolic agent. Seven months later, however, she sustained similar insufficiency fracture on the left femoral neck and was treated with the same method. She developed right inguinal pain again approximately eight months after her right side operation. The results of imaging tests revealed that her insufficiency fracture was converted to complete fracture, and that the fracture gap had widened as well. Her right hip was revised with hemiarthroplasty. A histological exam of the fracture site revealed evidence of decreased bone healing. Long-term administration of anti-resorptive drug prevents bone healing and remodeling and can result in atypical fractures of the femoral neck. Osteosynthesis was difficult to accomplish despite the application of proactive fixation. Therefore, more rigid fixation and careful postoperative treatment should be considered.

Demineralized bone matrix, as a graft enhancer of auto-local bone in posterior lumbar interbody fusion.

STUDY DESIGN: A case controlled study with prospective data collection. PURPOSE: To evaluate the early influence and the final consequence of demineralized bone matrix (DBM) on auto-local bone as a graft enhancer in posterior lumbar interbody fusion (PLIF). OVERVIEW OF LITERATURE: DBM is known as an osteoinductive material; however, it has not been clearly recognized to enhance auto-local bone with a small amount. METHODS: Patients who had a PLIF were allocated into two groups. Group I (70 cases) used auto-local bone chips and group II (44 cases) used DBM as an additive to auto-local bone, 1 mL per a segment. Group selection was alternated. Early assessment was performed by computed tomography at 6 months and final assessment was done by simple radiography after 24 months at least. The degree of bone formation was assessed by 4 grade scale. RESULTS: The subjects of both groups were homogenous and had similar Oswestry Disability Index at final assessment. The ratio of auto-local bone chips and DBM was 6:1. The degree of bone formation at 6 months after surgery was superior in group II. However, there was no significant difference between the two groups at the final assessment. CONCLUSIONS: DBM was not recognized to enhance auto-local bone with small amount.