Safety and potential effects of intrathecal injection of allogeneic human umbilical cord mesenchymal stem cell-derived exosomes in complete subacute spinal cord injury: a first-in-human, single-arm, open-label, phase I clinical trial.

OBJECTIVE: Neurological and functional impairments are commonly observed in individuals with spinal cord injury (SCI) due to insufficient regeneration of damaged axons. Exosomes play a crucial role in the paracrine effects of mesenchymal stem cells (MSCs) and have emerged as a promising therapeutic approach for SCI. Thus, this study aimed to evaluate the safety and potential effects of intrathecal administration of allogeneic exosomes derived from human umbilical cord MSCs (HUC-MSCs) in patients with complete subacute SCI. METHODS: This study was a single-arm, open-label, phase I clinical trial with a 12-month follow-up period. HUC-MSCs were extracted from human umbilical cord tissue, and exosomes were isolated via ultracentrifugation. After intrathecal injection, each participant a underwent complete evaluation, including neurological assessment using the American Spinal Injury Association (ASIA) scale, functional assessment using the Spinal Cord Independence Measure (SCIM-III), neurogenic bowel dysfunction (NBD) assessment using the NBD score, modified Ashworth scale (MAS), and lower urinary tract function questionnaire. RESULTS: Nine patients with complete subacute SCI were recruited. The intrathecal injection of allogeneic HUC-MSCs-exosomes was safe and well tolerated. No early or late adverse event (AE) attributable to the study intervention was observed. Significant improvements in ASIA pinprick (P-value = 0.039) and light touch (P-value = 0.038) scores, SCIM III total score (P-value = 0.027), and NBD score (P-value = 0.042) were also observed at 12-month after the injection compared with baseline. CONCLUSIONS: This study demonstrated that intrathecal administration of allogeneic HUC-MSCs-exosomes is safe in patients with subacute SCI. Moreover, it seems that this therapy might be associated with potential clinical and functional improvements in these patients. In this regard, future larger phase II/III clinical trials with adequate power are highly required. TRIAL REGISTRATION: Iranian Registry of Clinical Trials, IRCT20200502047277N1. Registered 2 October 2020, https://en.irct.ir/trial/48765 .

Predictive ability of hypotension prediction index and machine learning methods in intraoperative hypotension: a systematic review and meta-analysis.

INTRODUCTION: Intraoperative Hypotension (IOH) poses a substantial risk during surgical procedures. The integration of Artificial Intelligence (AI) in predicting IOH holds promise for enhancing detection capabilities, providing an opportunity to improve patient outcomes. This systematic review and meta analysis explores the intersection of AI and IOH prediction, addressing the crucial need for effective monitoring in surgical settings. METHOD: A search of Pubmed, Scopus, Web of Science, and Embase was conducted. Screening involved two-phase assessments by independent reviewers, ensuring adherence to predefined PICOS criteria. Included studies focused on AI models predicting IOH in any type of surgery. Due to the high number of studies evaluating the hypotension prediction index (HPI), we conducted two sets of meta-analyses: one involving the HPI studies and one including non-HPI studies. In the HPI studies the following outcomes were analyzed: cumulative duration of IOH per patient, time weighted average of mean arterial pressure < 65 (TWA-MAP < 65), area under the threshold of mean arterial pressure (AUT-MAP), and area under the receiver operating characteristics curve (AUROC). In the non-HPI studies, we examined the pooled AUROC of all AI models other than HPI. RESULTS: 43 studies were included in this review. Studies showed significant reduction in IOH duration, TWA-MAP < 65 mmHg, and AUT-MAP < 65 mmHg in groups where HPI was used. AUROC for HPI algorithms demonstrated strong predictive performance (AUROC = 0.89, 95CI). Non-HPI models had a pooled AUROC of 0.79 (95CI: 0.74, 0.83). CONCLUSION: HPI demonstrated excellent ability to predict hypotensive episodes and hence reduce the duration of hypotension. Other AI models, particularly those based on deep learning methods, also indicated a great ability to predict IOH, while their capacity to reduce IOH-related indices such as duration remains unclear.

Epidemiology of malignant gliomas in Iran: first report of Iranian National Population-based Cancer Registry, 2009-2017.

OBJECTIVE: Malignant gliomas constitute the most common type of primary malignant brain tumors. Most previous studies have evaluated the epidemiology of malignant gliomas in developed countries. Hence, there is a lack of evidence in this regard from developing countries. This study is the first epidemiological report on the status of malignant glioma in Iran between 2009 and 2017. METHODS: Data from the Iranian National Population-based Cancer Registry (covering 98% of the Iranian population) on CNS tumors recorded from 2009 to 2017 were used for analysis. Age-adjusted incidence rates were calculated by sex, tumor histology, tumor site, and year of diagnosis. Trend analysis of incidence rates was also performed. Survival data were recorded and the Cox proportional hazards model was used to evaluate underlying risk factors. RESULTS: A total of 8484 patients were diagnosed with malignant glioma between 2009 and 2017 in Iran. The overall age-adjusted incidence rate of malignant gliomas over the 9-year period was 1.71 per 100,000 persons. The most common histology of malignant gliomas was glioblastoma (81.4%). A significant increase in the incidence of malignant gliomas was found between 2009 and 2012. The median overall survival was 13.0 (95% CI 12.6-13.5) months over the study period. Older age groups, higher tumor grade, male sex, the first half of the study period, and receiving no treatment were significantly associated with worse prognoses. CONCLUSIONS: This study is the latest epidemiological report on the status of malignant gliomas in Iran. Although the overall incidence rate was lower than the rates in developed countries, several findings were consistent with those in prior reports.

Effects of Preoperative Use of Povidone-Iodine-Impregnated Dressing on Postoperative Rate of Surgical Site Infection in Patients Undergoing Posterolateral Lumbar Spinal Fusion Surgery: A Randomized, Nonblinded, Active-Controlled Trial.

BACKGROUND AND OBJECTIVES: No study has evaluated the efficacy of using preoperative antiseptic dressings in reducing the rate of surgical site infection (SSI) in spine surgery thus far. To investigate the efficacy of the use of preoperative povidone-iodine-impregnated antiseptic dressings in patients undergoing instrumented posterolateral lumbar spinal fusion. METHODS: This was a randomized, nonblinded, active-controlled, parallel-group clinical trial. Patients were randomly assigned to the 2 study groups, including treatment and control. Patients in the treatment group received povidone-iodine-impregnated antiseptic dressing applied to the anticipated incision site 12 hours before the operation. The control group merely received the standard perioperative care with no additional intervention or placebo. Patients were followed up for 90 days, and SSIs were recorded. RESULTS: A total of 200 patients were included in this study (100 in each arm). Three cases of SSI were observed in the treatment group compared with 12 in the control one. A significant reduction in the postoperative rate of SSI was observed in the treatment group compared with the control one (P = .029). In addition to study intervention (P = .029), body mass index (P = .005), smoking status (P = .005), duration of the procedure (P = .003), American Society of Anesthesiologists class (P = .002), and diabetes mellitus (P < .001) were significantly associated with the postoperative rate of SSI. CONCLUSION: To the best of our knowledge, this study for the first time showed that preoperative use of antiseptic dressings is significantly effective in reducing the rate of SSI in instrumented posterior lumbar spinal fusion surgery. Future studies are warranted to evaluate the efficacy of different preparations or the effectiveness of the present one in patients undergoing spine procedures with other surgical characteristics.

Suicide gene therapy using allogeneic adipose tissue-derived mesenchymal stem cell gene delivery vehicles in recurrent glioblastoma multiforme: a first-in-human, dose-escalation, phase I clinical trial.

BACKGROUND: Glioblastoma multiforme (GBM) is associated with remarkably poor prognosis, and its treatment is challenging. This investigation aimed to evaluate the safety of suicide gene therapy using allogeneic adipose tissue-derived mesenchymal stem cells (ADSCs) carrying herpes simplex virus-thymidine kinase (HSV-TK) gene for the first time in patients with recurrent GBM. METHODS: This study was a first-in-human, open-label, single-arm, phase I clinical trial with a classic 3 + 3 dose escalation design. Patients who did not undergo surgery for their recurrence were included and received this gene therapy protocol. Patients received the intratumoral stereotactic injection of ADSCs according to the assigned dose followed by prodrug administration for 14 days. The first dosing cohort (n = 3) received 2.5 × 105 ADSCs; the second dosing cohort (n = 3) received 5 × 105 ADSCs; the third dosing cohort (n = 6) received 10 × 105 ADSCs. The primary outcome measure was the safety profile of the intervention. RESULTS: A total of 12 patients with recurrent GBM were recruited. The median follow-up was 16 (IQR, 14-18.5) months. This gene therapy protocol was safe and well tolerated. During the study period, eleven (91.7%) patients showed tumor progression, and nine (75.0%) died. The median overall survival (OS) was 16.0 months (95% CI 14.3-17.7) and the median progression-free survival (PFS) was 11.0 months (95% CI 8.3-13.7). A total of 8 and 4 patients showed partial response and stable disease, respectively. Moreover, significant changes were observed in volumetric analysis, peripheral blood cell counts, and cytokine profile. CONCLUSIONS: The present clinical trial, for the first time, showed that suicide gene therapy using allogeneic ADSCs carrying the HSV-TK gene is safe in patients with recurrent GBM. Future phase II/III clinical trials with multiple arms are warranted to validate our findings and further investigate the efficacy of this protocol compared with standard therapy alone. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT), IRCT20200502047277N2. Registered 8 October 2020, https://www.irct.ir/ .

Case report: Stem cell-based suicide gene therapy mediated by the herpes simplex virus thymidine kinase gene reduces tumor progression in multifocal glioblastoma.

Introduction: The prognosis for glioblastoma multiforme (GBM), a malignant brain tumor, is poor despite recent advancements in treatments. Suicide gene therapy is a therapeutic strategy for cancer that requires a gene to encode a prodrug-activating enzyme which is then transduced into a vector, such as mesenchymal stem cells (MSCs). The vector is then injected into the tumor tissue and exerts its antitumor effects. Case presentation: A 37-year-old man presented to our department with two evident foci of glioblastoma multiforme at the left frontal and left parietal lobes. The patient received an injection of bone marrow-derived MSCs delivering the herpes simplex virus thymidine kinase (HSV-tk) gene to the frontal focus of the tumor, followed by ganciclovir administration as a prodrug for 14 days. For follow-up, the patient was periodically assessed using magnetic resonance imaging (MRI). The growth and recurrence patterns of the foci were assessed. After the injection on 09 February 2019, the patient's follow-up appointment on 19 December 2019 MRI revealed a recurrence of parietal focus. However, the frontal focus had a slight and unremarkable enhancement. On the last follow-up (18 March 2020), the left frontal focus had no prominent recurrence; however, the size of the left parietal focus increased and extended to the contralateral hemisphere through the corpus callosum. Eventually, the patient passed away on 16 July 2020 (progression-free survival (PFS) = 293 days, overall survival (OS) = 513 days). Conclusion: The gliomatous focus (frontal) treated with bone marrow-derived MSCs carrying the HSV-TK gene had a different pattern of growth and recurrence compared with the non-treated one (parietal). Trial registration: IRCT20200502047277N2. Registered 10 May 2020-Retrospectively registered, https://eng.irct.ir/trial/48110.

Safety and Potential Efficacy of Selective Dorsal Rhizotomy in Adults with Spinal Cord Injury-Induced Spasticity: An Open-Label, Non-Randomized, Single-Arm Trial.

BACKGROUND: Despite the abundant literature on the use of selective dorsal rhizotomy (SDR) in spastic cerebral palsy, no investigation has evaluated its use in adult patients with chronic spinal cord injury (SCI)-induced spasticity. The present investigation aimed to evaluate the safety and potential efficacy of SDR in chronic SCI-induced spasticity for the first time. METHODS: In this open-label, single-arm, non-randomized clinical trial, all patients were assigned to the single study intervention arm and underwent SDR. The primary outcome measure was the safety profile of SDR. Secondary outcome measures were Modified Ashworth Scale, Penn Spasm Frequency Scale, visual analog scale for spasticity, Spinal Cord Injury Spasticity Tool, Spinal Cord Independence measure version III, and Short Form 36 Health Survey Questionnaire. RESULTS: Six patients with cervical SCI and 4 with thoracic SCI were allocated to the single study intervention arm. No adverse event attributable to the SDR was found. Moreover, all secondary outcome measures of the study improved significantly over the study period (P < 0.001). Multiple regression analysis also found a significant association between level of injury and changes in average Modified Ashworth Scale scores (P = 0.041), Spinal Cord Injury Spasticity Tool score (P = 0.013), and Spinal Cord Independence measure version III total (P = 0.002) and mobility domain scores (P = 0.004) at 12-month postoperatively. CONCLUSIONS: This clinical trial indicated that SDR is a safe and potentially effective procedure in patients with severe and intractable SCI-induced spasticity. However, future clinical trials with larger sample sizes and adequate power are required to validate our findings regarding efficacy.

Effects of local intraoperative epidural use of triamcinolone acetonide-soaked Gelfoam on postoperative outcomes in patients undergoing posterolateral lumbar spinal fusion surgery: a randomized, placebo-controlled, double-blind trial.

OBJECTIVE: Prior evidence has supported the use of local intraoperative epidural steroids in lumbar discectomy for improvements in postoperative pain and outcomes. However, currently there is a paucity of data regarding the efficacy of local epidural steroids in spinal fusion procedures. The present investigation aimed to evaluate the impact of local epidural administration of triamcinolone acetonide-soaked Gelfoam on postoperative pain and patient-reported outcomes in patients undergoing instrumented posterolateral lumbar spinal fusion. METHODS: In this randomized, double-blind, placebo-controlled trial, patients were randomly divided into two groups (treatment and control). Patients in the treatment group received a Gelfoam carrier soaked in 1 ml of triamcinolone acetonide (40 mg), which was placed over the nerve roots in the epidural space before the closure. Patients in the control group received a Gelfoam carrier soaked in normal saline in a similar fashion to the treatment group. Patients were followed up during their hospital stay and at 4 and 12 weeks postoperatively. The primary outcome measure was early postoperative visual analog scale (VAS) scores for pain both at rest and with movement. RESULTS: A total of 100 patients were recruited in this study and were randomly allocated to the treatment or control group. No significant difference was found in baseline demographic, clinical, and surgical characteristics between the two groups. Postoperative VAS scores for pain both at rest and with movement were comparable between the treatment and control groups. Cumulative morphine consumption, length of hospital stay, and incidence of postoperative complications such as surgical site infection were also similar between the two groups. There was no significant difference in patient-reported outcomes including VAS scores for back and leg pain as well as the Oswestry Disability Index at 4 and 12 weeks postoperatively. The proportion of patients who achieved a minimum clinically important difference for patient-reported outcomes were also similar between the two groups. CONCLUSIONS: In contrast to the existing literature on the beneficial use of local intraoperative epidural steroids in conventional lumbar discectomy, the present study did not demonstrate such significant efficacy for the use of local epidural steroids in instrumented posterolateral lumbar spinal fusion. However, there is still a lack of evidence in this regard and further high-quality clinical trials are required to evaluate the efficacy of local epidural steroids in this group of patients.

The Effect of Vitamin D Deficiency on Outcomes of Patients Undergoing Elective Spinal Fusion Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVES: Vitamin D plays a major role in bone metabolism, regulating calcium and phosphorus homeostasis, along with bone growth and remodeling processes. The objective of the present study was to assess the effect of vitamin D deficiency on clinical outcomes following elective spinal fusion surgery by conducting a meta-analysis on the relevant literature. METHODS: Studies included in this analysis involved patients older than 18 years who underwent elective spinal fusion surgery. The number of patients as well as visual analog scale (VAS) and Oswestry Disability Index (ODI) in groups with and without vitamin D deficiency were required to be reported in eligible studies. Of the 179 articles identified, 7 met the inclusion criteria and were included in the analysis. RESULTS: Seven studies, including 1188 patients, reported the relationship between vitamin D deficiency and clinical outcomes in patients undergoing elective spinal fusion surgery. Five studies reported VAS as a primary outcome. The combined results using a random-effects model showed reduction in VAS after elective spinal fusion surgery in group with vitamin D deficiency, but no statistically significant association was identified between vitamin D deficiency and VAS. ODI was assessed and reported as an outcome measure in 5 of the included studies. The combined results showed an increase in ODI following elective spinal fusion surgery in the vitamin D-deficient group compared to the group with normal levels of vitamin D. In addition, a significant association was observed between ODI and vitamin D deficiency. CONCLUSIONS: Vitamin D deficiency may negatively affect the postoperative outcomes in elective spinal fusion surgery. Preoperative optimization of vitamin D levels would seem appropriate. Future high-quality studies are highly warranted to evaluate this. CLINICAL RELEVANCE: This meta-analysis demonstrated a significant association between vitamin D deficiency and postoperative ODI scores in patients undergoing elective spinal fusion surgery.

Analgesic Effects of Preoperative Combination of Oral Pregabalin and Intravenous Magnesium Sulfate on Postoperative Pain in Patients Undergoing Posterolateral Spinal Fusion Surgery: A 4-arm, Randomized, Double-blind, Placebo-controlled Trial.

BACKGROUND: Multimodal perioperative pain management including nonopioid analgesia is a major pillar of enhanced recovery after surgery programs. The aim of this study was to investigate the analgesic efficacy of the preoperative combination of 2 nonopioid drugs, oral pregabalin and intravenous magnesium sulfate, in patients undergoing posterolateral lumbar spinal fusion. METHODS: This 4-arm, randomized, double-blind, placebo-controlled trial included 104 patients randomly allocated to receive: magnesium sulfate and pregabalin (MP), magnesium sulfate and oral placebo (M), 0.9% saline and oral pregabalin (P), and 0.9% saline and oral placebo (C). The study drugs were administered 1 hour preoperatively. The primary outcome was the cumulative morphine consumption on postoperative day 1. Secondary outcomes included visual analog scale scores for leg pain at rest and with movement, and postoperative nausea and vomiting (PONV) in the first 48 hours after surgery. RESULTS: Cumulative morphine consumption on postoperative day 1 was lower in group MP (19.6±8.0 mg) compared with group M (32.6±9.5 mg; P <0.001), group P (28.9±9.4 mg; P =0.001), or group C (38.8±10.3 mg; P <0.001). Multiple linear regression demonstrated a significant association between group MP and cumulative morphine consumption (B=-5.4 [95% CI, -7.1, -3.7], P <0.001). Visual analog scale scores for leg pain at rest and with movement were lower in group MP compared with other groups ( P =0.006 and <0.001). The incidence of PONV was also lowest in group MP ( P =0.032). CONCLUSIONS: Preoperative administration of oral pregabalin and intravenous magnesium sulfate resulted in reduced morphine consumption and greater analgesic effect than the use of each drug individually or placebo in patients undergoing posterolateral lumbar spinal fusion.

The Impact of the Coronavirus Disease 2019 Pandemic on Neurosurgical Practice and Feasibility of Safe Resumption of Elective Procedures During this Era in a Large Referral Center in Tehran, Iran: An Unmatched Case-Control Study.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic has considerably affected surgical practice. The present study aimed to investigate the effects of the pandemic on neurosurgical practice and the safety of the resumption of elective procedures through implementing screening protocols in a high-volume academic public center in Iran, as one of the countries severely affected by the pandemic. METHODS: This unmatched case-control study compared 2 populations of patients who underwent neurosurgical procedures between June 1, 2019 and September 1, 2019 and the same period in 2020. In the prospective part of the study, patients who underwent elective procedures were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection postoperatively to evaluate the viability of our screening protocol. RESULTS: Elective and emergency procedures showed significant reduction during the pandemic (59.4%, n = 168 vs. 71.3%, n = 380) and increase (28.7%, n = 153 vs. 40.6%, n = 115, respectively; P = 0.003). The proportional distribution of neurosurgical categories remained unchanged during the pandemic. Poisson regression showed that the reduction in total daily admissions and some categories, including spine, trauma, oncology, and infection were significantly correlated with the pandemic. Among patients who underwent elective procedures, 0 (0.0%) and 26 (16.25%) had positive test results on days 30 and 60 postoperatively, respectively. Overall mortality was comparable between the pre-COVID-19 and COVID-19 periods, yet patients with concurrent SARS-CoV-2 infection showed substantially higher mortality (65%). CONCLUSIONS: By implementing safety and screening protocols with proper resource allocation, the emergency care capacity can be maintained and the risk minimized of hospital-acquired SARS-CoV-2 infection, complications, and mortality among neurosurgical patients during the pandemic. Similarly, for elective procedures, according to available resources, hospital beds can be allocated for patients with a higher risk of delayed hospitalization and those who are concerned about the risk of hospital-acquired infection can be reassured.

Cauda equina syndrome due to herpes simplex virus type 2-associated meningoradiculitis (Elsberg syndrome) after posterior lumbar spinal fusion surgery: Case report and review of literature.

Elsberg syndrome is a rare but well-defined clinical condition, including acute or subacute lumbosacral meningoradiculitis, which might be accompanied by myelitis and is often associated with herpes simplex virus type 2 (HSV-2) infection. We report the case of an immunocompetent 24-year-old man who presented with perineal pain, saddle hypoesthesia, and urinary retention associated with Elsberg syndrome due to HSV-2 infection 20-day after the posterior lumbar spinal fusion surgery. Lumbar magnetic resonance imaging (MRI) with gadolinium enhancement showed mildly enhanced and swollen right sacral nerve roots. One week after the admission, electromyography and nerve conduction studies (EMG-NCS) demonstrated severe axonal damage and radiculopathy at right S3 and S4 roots. Cerebrospinal fluid (CSF) analysis revealed lymphocytic pleocytosis, elevated protein, positive HSV-2 IgG index, and positive HSV-2 polymerase chain reaction (PCR). The patient was treated with intravenous acyclovir for 14 days and showed a gradual improvement in anal sphincter control and urination. Therefore, according to our findings, surgery might have an immunosuppressing role, and in cases with symptoms of cauda equina syndrome (CES) and systemic infection, in the postoperative setting, viral meningoradiculitis should be considered.

Changed pattern of hospital admission in stroke during COVID-19 pandemic period in Iran: a retrospective study.

BACKGROUND: Some previous reports have shown a reduced number of admission in stroke cases during the coronavirus disease 2019 (COVID-19) pandemic period. The present study aimed to investigate this changing pattern and the potential causes behind it at an academic neurology and neurosurgery center in Iran. METHODS: Patients admitted to our center with the diagnosis of ischemic and hemorrhagic stroke, between March 1, 2019, Jun 1, 2019, and the similar 3-month period in 2020 (COVID-19 pandemic period), were compared in terms of clinical characteristics and outcome. Poisson regression was also conducted to assess the correlation between daily admissions and the COVID-19 pandemic period. RESULTS: A total of 210 patients with stroke (ischemic and hemorrhagic) in 2019 were compared with 106 patients in 2020. COVID-19 pandemic period was significantly associated with the decline in the number of daily admissions in ischemic stroke (IRR, 0.51 [95% CI, 0.4-0.64]). A significant reduction (P = 0.003) in time from onset to arrival at hospital from median 12 h [IQR, 5-32] in 2019 to median 6 h [IQR, 4-16] in 2020 was found in ischemic stroke cases. National Institute of Health Stroke Scale (NIHSS) was significantly increased (P < 0.001) from median 4 [IQR, 2-7] in 2019 to median 9 [IQR, 4-14] in 2020. Glasgow coma scale (GCS) was significantly decreased from 13.9 (SD, 2) in 2019 to 12.8 (SD, 2.9) in 2020 (P < 0.001). CONCLUSIONS: The present study provided new pieces of evidence regarding the changed pattern of hospital admission in stroke especially the possible reasons for its decline.

Effects of perioperative magnesium sulfate infusion on intraoperative blood loss and postoperative analgesia in patients undergoing posterior lumbar spinal fusion surgery: A randomized controlled trial.

OBJECTIVE: Many studies have suggested the anti-nociceptive role for magnesium either as an adjunct for postoperative pain. Although several studies have been carried out to evaluate the anti-nociceptive effect of magnesium, there is still considerable uncertainty. PATIENTS AND METHODS: Eighty patients who underwent posterior spinal fusion were randomly divided into two groups (magnesium and saline). Changes in cell count, magnesium concentration and coagulation status were assessed one hour after operation at both group and compared to baseline. At recovery room, their pain score was assessed according to 10 points visual analogue scale (VAS). Morphine consumption was evaluated at regular times after the surgery by patient controlled analgesia (PCA) device. RESULTS: VAS scores were significantly lower in the magnesium group. Cumulative PCA morphine consumption after the surgery was significantly lower in the magnesium group. Pre and postoperative values for haemoglobin, platelet count, Prothrombin Time (PT), fibrinogen were not significantly different. There was a significant increase in activated Partial Thromboplastin Time (aPTT), International Normalized Ratio (INR), and bleeding time (BT), one hour after the operation in the magnesium group but intraoperative blood loss was similar in both groups. CONCLUSIONS: Perioperative magnesium sulfate infusion improves the postoperative analgesia, decreases the amount of morphine consumption after the operation and does not change the intraoperative bleeding in patients undergoing posterior spinal fusion surgery.