Mohamed Amin Roshdy Soliman

Lateral mass screw (LMS) fixation for the treatment of subaxial cervical spine instability or deformity has been traditionally associated with few neurovascular complications. However, cervical pedicle screw (CPS) fixation has recently increased in popularity, especially with navigation assistance, because of the higher pullout strength of the pedicle screws. To their knowledge, the authors conducted the first meta-analysis comparing the complication rates during and/or after CPS and LMS placement for different pathologies causing cervical spine instability. A systematic literature search of PubMed and Embase from inception to January 12, 2021 was performed to identify studies reporting CPS and/or LMS-related complications. Complications were categorized into intraoperative and early postoperative (within 30 days of surgery) and late postoperative (after 30 days from surgery) complications. All studies that met the prespecified inclusion criteria were pooled and cumulatively analyzed. A total of 24 studies were conducted during the time frame of the search and comprising 1768 participants and 8636 subaxially placed screws met the inclusion criteria. The CPS group experienced significantly more postoperative C5 palsy (odds ratio [OR] = 3.48, 95% confidence interval [CI] = 1.27-9.53, p < 0.05). Otherwise, there were no significant differences between the LMS and CPS groups. There were no significant differences between the CPS and LMS groups in terms of neurovascular procedure-related complications other than significantly more C5 palsy in the CPS group.

OBJECTIVE: Pedicle screw insertion for stabilization after lumbar fusion surgery is commonly performed by spine surgeons. With the advent of navigation technology, the accuracy of pedicle screw insertion has increased. Robotic guidance has revolutionized the placement of pedicle screws with 2 distinct radiographic registration methods, the scan-and-plan method and CT-to-fluoroscopy method. In this study, the authors aimed to compare the accuracy and safety of these methods.

METHODS: A retrospective chart review was conducted at 2 centers to obtain operative data for consecutive patients who underwent robot-assisted lumbar pedicle screw placement. The newest robotic platform (Mazor X Robotic System) was used in all cases. One center used the scan-and-plan registration method, and the other used CT-to-fluoroscopy for registration. Screw accuracy was determined by applying the Gertzbein-Robbins scale. Fluoroscopic exposure times were collected from radiology reports.

RESULTS: Overall, 268 patients underwent pedicle screw insertion, 126 patients with scan-and-plan registration and 142 with CT-to-fluoroscopy registration. In the scan-and-plan cohort, 450 screws were inserted across 266 spinal levels (mean 1.7 ± 1.1 screws/level), with 446 (99.1%) screws classified as Gertzbein-Robbins grade A (within the pedicle) and 4 (0.9%) as grade B (< 2-mm deviation). In the CT-to-fluoroscopy cohort, 574 screws were inserted across 280 lumbar spinal levels (mean 2.05 ± 1.7 screws/ level), with 563 (98.1%) grade A screws and 11 (1.9%) grade B (p = 0.17). The scan-and-plan cohort had nonsignificantly less fluoroscopic exposure per screw than the CT-to-fluoroscopy cohort (12 ± 13 seconds vs 11.1 ± 7 seconds, p = 0.3).

CONCLUSIONS: Both scan-and-plan registration and CT-to-fluoroscopy registration methods were safe, accurate, and had similar fluoroscopy time exposure overall.

Congenital hydrocephalus affects approximately one in 1000 newborn children and is fatal in approximately 50% of untreated cases. The currently known management protocols usually necessitate multiple interventions and long-term use of healthcare resources due to a relatively high incidence of complications, and many of them mostly provide a treatment of the effect rather than the cause of cerebrospinal fluid flow reduction or outflow obstruction. Future studies discussing etiology specific hydrocephalus alternative treatments are needed. We systematically reviewed the available literature on the effect of ciliary abnormality on congenital hydrocephalus pathogenesis, to open a discussion on the feasibility of factoring ciliary abnormality in future research on hydrocephalus treatment modalities. Although there are different forms of ciliopathies, we focused in this review on primary ciliary dyskinesia. There is growing evidence of association of other ciliary syndromes and hydrocephalus, such as the reduced generation of multiple motile cilia, which is distinct from primary ciliary dyskinesia. Data for this review were identified by searching PubMed using the search terms 'hydrocephalus,' 'Kartagener syndrome,' 'primary ciliary dyskinesia,' and 'immotile cilia syndrome.' Only articles published in English and reporting human patients were included. Seven studies met our inclusion criteria, reporting 12 cases of hydrocephalus associated with primary ciliary dyskinesia. The patients had variable clinical presentations, genetic backgrounds, and ciliary defects. The ependymal water propelling cilia differ in structure and function from the mucus propelling cilia, and there is a possibility of isolated non-syndromic ependymal ciliopathy causing only hydrocephalus with growing evidence in the literature for the association ependymal ciliary abnormality and hydrocephalus. Abdominal and thoracic situs in children with hydrocephalus can be evaluated, and secondary damage of ependymal cilia causing hydrocephalus in cases with generalized ciliary abnormality can be considered.

Glioblastoma is one of the most aggressive types of cancer with success of therapy being hampered by the existence of treatment resistant populations of stem-like Tumour Initiating Cells (TICs) and poor blood-brain barrier drug penetration. Therapies capable of effectively targeting the TIC population are in high demand. Here, we synthesize spherical diketopyrrolopyrrole-based Conjugated Polymer Nanoparticles (CPNs) with an average diameter of 109 nm. CPNs were designed to include fluorescein-conjugated Hyaluronic Acid (HA), a ligand for the CD44 receptor present on one population of TICs. We demonstrate blood-brain barrier permeability of this system and concentration and cell cycle phase-dependent selective uptake of HA-CPNs in CD44 positive GBM-patient derived cultures. Interestingly, we found that uptake alone regulated the levels and signaling activity of the CD44 receptor, decreasing stemness, invasive properties and proliferation of the CD44-TIC populations in vitro and in a patient-derived xenograft zebrafish model. This work proposes a novel, CPN- based, and surface moiety-driven selective way of targeting of TIC populations in brain cancer.

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications. We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms "vascular injury" and "lateral lumbar surgery." Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0-15.4% and minor vascular injury occurred in 0-6% of lateral lumbar fusions. The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

Butterfly glioblastoma (bGBM) is a grade 4 glioma with a poor prognosis. Surgical treatment of these cancers has been reviewed in the literature with some recent studies supporting resection as a safe and effective treatment instead of biopsy and adjuvant therapy. This meta-analysis was designed to determine whether there are significant differences in overall survival (OS) and postoperative neurologic deficits (motor, speech, and cranial nerve) following intervention in patients who underwent tumor resection as part of their treatment, compared to patients who underwent biopsy without surgical resection. A literature search was conducted using PubMed (National Library of Medicine) and Embase (Elsevier) to identify articles from each database's earliest records to May 25, 2021, that directly compared the outcomes of biopsy and resection in bGBM patients and met predetermined inclusion criteria. A meta-analysis was conducted to compare the effects of the two management strategies on OS and postoperative neurologic deficits. Six articles met our study inclusion criteria. OS was found to be significantly longer for the resection group at 6 months (odds ratio [OR] 2.94, 95% confidence interval [CI] 1.23-7.05) and 12 months (OR 3.75, 95% CI 1.10-12.76) than for the biopsy group. No statistically significant differences were found in OS at 18 and 24 months. Resection was associated with an increased rate of postoperative neurologic deficit (OR 2.05, 95% CI 1.02-4.09). Resection offers greater OS up to 1 year postintervention than biopsy alone; however, this comes at the cost of higher rates of postoperative neurologic deficits.

BACKGROUND: With growing emphasis on high-value care, many institutions have been working on improving surgical efficiency, quality, and complication reduction. Unfortunately, data are limited regarding perioperative factors that may influence length of stay (LOS) following transforaminal lumbar interbody fusion (TLIF). We sought to design a predictive algorithm that determined patients at risk of prolonged LOS after TLIF. The goal was to identify patients who would benefit from preoperative intervention aimed to reduce LOS.

METHODS: We conducted a review of perioperative data for patients who underwent TLIF between 2014 and 2019. Univariate and multivariate stepwise regression models were used to analyze risk factor effects on postoperative LOS.

RESULTS: Two hundred and sixty-nine patients were identified (57.2% women). Mean age at surgery was 61.7 ± 12.3 years. Mean postoperative LOS was 3.08 ± 1.54 days. In multivariate analysis, American Society of Anesthesiologists class (odds ratio [OR] = 1.441, 95% confidence interval [CI] 1.321-1.571), preoperative functional status (OR = 1.237, 95% CI 1.122-1.364), Oswestry Disability Index (OR = 1.010, 95% CI 1.004-1.016), and estimated blood loss (OR = 1.050, 95% CI 1.003-1.101) were independent risk factors for postoperative LOS ≥ 5 days. The final model had an area under the curve of 0.948 with good discrimination and was implemented in the form of an online calculator ( https://spine.shinyapps.io/TLIF_LOS/ ).

CONCLUSION: The prediction tool derived can be useful for assessing likelihood of prolonged LOS in patients undergoing TLIF. With external validation, this calculator may ultimately assist healthcare providers in identifying patients at risk for prolonged hospitalization so preoperative interventions can be undertaken to reduce LOS, thus reducing resource utilization.

BACKGROUND: Persistent opioid utilization after spine surgery is a rising complication among both preoperatively opioid-naïve and opioid-tolerant patients. To our knowledge, this is the first meta-analysis to determine the prevalence and characterize the risk factors that predispose patients to prolonged opioid use (≥3 months) after lumbar fusion.

METHODS: Studies were identified through searches in PubMed and EMBASE from each database's earliest records to February 1, 2022. We included observational studies examining the risk factors and rates of prolonged opioid use following lumbar fusion. Pooled odds ratios (ORs) or standardized mean differences with corresponding 95% confidence intervals (CI) were estimated using inverse-variance methods.

RESULTS: In this meta-analysis of 12 studies encompassing 80,935 patients, 40.2% of patients continued to fill opioid prescriptions ≥3 months after lumbar fusion. Significant sociodemographic predictors included Medicare or Medicaid insurance (OR=1.60, 95% CI 1.36-1.88), African-American ethnicity (OR=1.29, 95% CI 1.18-1.41), being from the Southern United States (OR=1.18, 95% CI 1.11-1.25), or women (OR=1.10, 95% CI 1.01-1.20). Being from the Midwestern United States (OR=0.80, 95% CI 0.75-0.85) was found to be a protective factor. Comorbidities associated with increased risk of prolonged opioid use were preoperative opioid use (OR=5.76, 95% CI 3.52-9.41), drug abuse (OR=3.11, 95% CI 2.37-4.08), alcohol abuse (OR=2.37, 95% CI 2.14-2.64), psychiatric disorders (OR=2.29, 95% CI 1.94-2.70), smoking history (OR=1.81, 95% CI 1.23-2.66), arthritis (OR=1.35, 95% CI 1.29-1.40), and higher American Society of Anesthesiologists score (standardized mean difference=0.72, 95% CI 0.61-0.82).

CONCLUSIONS: The high prevalence of prolonged opioid use after lumbar fusion underscores the importance of screening patients for comorbidities and implementing targeted strategies to minimize opioid misuse.

BACKGROUND: Lateral lumbar interbody fusion has inherent limitations, such as the necessity to reposition the patient. To overcome this limitation, the prone transpsoas (PTP) approach for lateral lumbar interbody fusion has been developed.

OBJECTIVE: To report clinical and radiographic outcome measures of a series of patients who underwent PTP at our hospital.

METHODS: A retrospective chart review was conducted to identify patients who underwent PTP for degenerative lumbar spine disease between September 2019 and August 2021. A thorough analysis of clinical and radiographic outcome measures for these patients was conducted.

RESULTS: Our search resulted in the identification of 15 consecutive patients. Four patients were operated using the assistance of fluoroscopy-based instrument tracking. Overall, the mean follow-up duration was 11.9 ± 7.9 months. Radiographically, the PTP approach resulted in significant postoperative improvement of lumbar lordosis ( P = .03) and pelvic incidence minus lumbar lordosis ( P < .005). No significant difference was found postoperatively in other regional sagittal alignment parameters, including pelvic tilt, sacral slope, or pelvic incidence. Clinically, the patients' Oswestry Disability Indices ( P = .002) and Short Form Survey-12 Physical Scores improved significantly ( P = .01). The estimated mean blood loss for patients who underwent the PTP procedure was 137.7 ± 96.4 mL, the mean operative time was 212.5 ± 77.1 minutes, and the mean hospital stay was 2.7 ± 1.4 days. One patient each had superficial wound infection, transient paralytic ileus, transient pulmonary embolism, transient urinary retention, or required revision lumbar surgery.

CONCLUSION: This study demonstrates that the PTP approach is associated with significant improvement in radiographic and clinical outcomes.

BACKGROUND CONTEXT: Cage subsidence following transforaminal lumbar interbody fusion (TLIF) has been associated with poor bone quality. Current evidence suggests that the magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score correlates with poor bone quality.

PURPOSE: To our knowledge, this is the first study to assess whether the VBQ score can predict the occurrence of postoperative cage subsidence after TLIF surgery.

DESIGN/SETTING: Retrospective single-center cohort.

PATIENT SAMPLE: Patients undergoing single-level TLIF for degenerative spine disease between February 2014 and October 2021.

OUTCOME MEASURES: Extent of subsidence.

METHODS: Demographic, procedure-related, and radiographic data were collected for study patients. VBQ scores were determined from preoperative T1-weighted MRI. Subsidence was defined as ≥2 mm of migration of the cage into the superior or inferior end plate or both. Univariate and multivariate logistic regression were used to determine the correlation between potential risk factors for subsidence and actual subsidence rates.

RESULTS: Subsidence was observed among 42 of the 74 study patients. The mean VBQ scores were 2.9±0.5 for patients with subsidence and 2.5±0.5 for patients without subsidence. The difference among groups was significant (p=.003). On multivariate logistic regression, a higher VBQ score was significantly associated with an increased risk of subsidence (OR=1.5, 95% CI=1.160-1.973, p=.004) and was the only significant independent predictor of subsidence after TLIF.

CONCLUSION: We found that a higher VBQ score was significantly associated with cage subsidence following TLIF. The MRI-VBQ score may be a valuable tool for assisting in identifying patients at risk of cage subsidence following TLIF.

BACKGROUND: Cerebrospinal fluid (CSF) infection is one of the most common and serious complications of shunt placement. The CSF shunt infections are preferably treated with intravenous antibiotics, infected shunt removal, repeated tapping (infants) or placement of an external ventricular drainage (EVD) device, and placement of a new shunt once the CSF is sterile. The tapping through the anterior fontanelle is commonly used instead of the EVD in developing countries to manage CSF infection in open anterior fontanelle patients. To the best of our knowledge, this would be considered the first reported case of distant epidural hematoma after closed ventricular tapping.

CASE DESCRIPTION: We report a case of 6-months child with Chiari malformation (Type II) presenting to us with a shunt infection with possible obstruction. CSF was aspirated for examination through a tap through the anterior fontanelle followed by the development of extradural hemorrhage far from the tapping site.

CONCLUSION: EDH after a transfontanellar ventricular tap can rapidly evolve and lead to patient death. This report raises the awareness of the neurosurgeons to this possible complication that can happen and leads to major complications. Monitoring the conscious level would be needed after ventricular tapping to detect this possible complication.

BACKGROUND: COVID-19 has had a significant impact on the economy, health care, and society as a whole. To prevent the spread of infection, local governments across the United States issued mandatory lockdowns and stay-at-home orders. In the surgical world, elective cases ceased to help "flatten the curve" and prevent the infection from spreading to hospital staff and patients. We explored the effect of the cancellation of these procedures on trainee operative experience at our high-volume, multihospital neurosurgical practice.

METHODS: Our department cancelled all elective cases starting March 16, 2020, and resumed elective surgical and endovascular procedures on May 11, 2020. We retrospectively reviewed case volumes for 54 days prelockdown and 54 days postlockdown to evaluate the extent of the decrease in surgical volume at our institution. Procedure data were collected and then divided into cranial, spine, functional, peripheral nerve, pediatrics, and endovascular categories.

RESULTS: Mean total cases per day in the prelockdown group were 12.26 ± 7.7, whereas in the postlockdown group, this dropped to 7.78 ± 5.5 ( = 0.01). In the spine category, mean cases per day in the prelockdown group were 3.13 ± 2.63; in the postlockdown group, this dropped to 0.96 ± 1.36 ( < 0.001). In the functional category, mean cases per day in the prelockdown group were 1.31 ± 1.51, whereas in the postlockdown group, this dropped to 0.11 ± 0.42 ( < 0.001). For cranial ( = 0.245), peripheral nerve ( = 0.16), pediatrics ( = 0.34), and endovascular ( = 0.48) cases, the volumes dropped but were not statistically significant decreases.

CONCLUSION: The impact of this outbreak on operative training does appear to be significant based solely on statistics. Although the drop in case volumes during this time can be accounted for by the pandemic, it is important to understand that this is a multifactorial effect. Further studies are needed for these results to be generalizable and to fully understand the effect this pandemic has had on trainee operative experience.

BACKGROUND: Postoperative pain after complex revision spine surgery, especially for the treatment of persistent spinal pain syndrome (PSPS), is frequently severe and can be debilitating, requiring the use of intravenous and oral opioids. To the best of our knowledge, the present study is the first to evaluate the effectiveness and safety of a continuous infusion regional anesthesia pump placed after thoracopelvic fusion for the treatment of PSPS.

METHODS: We performed a retrospective comparative study of consecutive patients who had undergone thoracopelvic fusion for PSPS. The patients included in the present study had either had a continuous infusion regional anesthesia pump placed during surgery or had not (control). Demographics, use of preoperative and postoperative opioids, postoperative adverse events, length of hospital stay, and 90-day readmission were recorded.

RESULTS: The patients in the pump group (n = 14) had used fewer opioids during their hospital stay compared with the control group (n = 12; P = 0.6). This difference was greater for postoperative days 1 and 2 (P = 0.3 and P = 0.2, respectively). No significant difference was found in opioid usage during the first 14 days after surgery (P = 0.8) or at the 3-month postoperative follow-up evaluation (P = 0.8). Furthermore, no significant difference was found between the 2 groups in terms of postoperative complications. The pump group had a 1.4-day shorter hospital stay (P = 0.7). The control group had more 90-day readmissions than did the pump group (P = 0.2).

CONCLUSIONS: Despite showing a trend toward less usage of opioids during the first 2 days after surgery and a shorter hospital stay with no increased complications in the pump group, the study data failed to demonstrate a statistically significant difference between the two groups.

BACKGROUND: There is a paucity of data on outcomes following four-level anterior cervical discectomy and fusions (ACDFs), especially the sagittal balance (SB) parameters.

OBJECTIVE: We aimed to review the long-term clinical and radiographic outcomes for 41 consecutive patients that underwent instrumented four-level ACDF.

MATERIALS AND METHODS: Records of 27 men and 14 women, aged 40-68 years, who underwent instrumented four-level ACDF and plating at C3-C7 (n = 37) or C4-T1 (n = 4) were retrospectively analyzed. Clinical outcomes that were assessed were the visual analog scale (VAS) for pain, neck disability index (NDI), Odom's criteria, improvement of symptoms, intraoperative and postoperative complications, SB, and need for revision surgery.

RESULTS: The mean follow-up was 65 ± 36.3 months. The mean VAS for arm and neck pain significantly improved from 7.7 ± 1.4 to 3.5 ± 1.7 (P < 0.001). The NDI score significantly improved from 31 ± 8.2 to 19.3 ± 8.1 (P < 0.001). Concerning Odom's criteria, the grades were excellent (14), good (17), fair (9), and poor (1). Concerning intraoperative and postoperative complications, 10 cases developed dysphagia, 3 cases developed temporary dysphonia, 2 cases developed a postoperative hematoma, 1 patient developed C5 palsy, 1 vertebral artery (VA) injury, and 1 case had superficial infection. The average length of stay (LOS) was 2.9 ± 3.7 days. Three patients needed another surgery (one adjacent segment and two posterior foraminotomies). Regarding the mean change in SB parameters, Cobb's angle (CA) (C2-C7) was 14° ± 8.3°, fusion angle (FA) was 10.9 ± 10.9°, cervical straight vertical alignment (cSVA) was 0.6 ± 0.5 cm, T1 slope was 2.3° ± 3.4°, and disc height (DH) was 1.3 ± 0.9 mm.

CONCLUSION: Instrumented four-level ACDF is safe with a satisfactory outcome and supplementary posterior fusion was not required in any case.

BACKGROUND: One of the most preventable errors of a surgeon's career is operating on the incorrect surgical site (ICSS). No study in any specialty has ever investigated the incidence of ICSS events in lower-income countries. This study focuses on identifying the occurrence of these events along with an analysis of potential causes leading to these unfortunate events.

METHODS: The authors distributed a survey to neurosurgical colleagues from around the world. These surgeons were first asked to identify details about their practice and incidence and personal experience with ICSS in their own careers. At the end of the survey, they responded to questions about their knowledge of safety checklists.

RESULTS: In this study there was a 63.4% response rate. When combined with those who participated through various social media platforms, there were 178 responses. The incidence rate for every 10,000 cases performed was found to be 22.8 in the cranial group, 88.6 in the cervical group, and 158.8 in the lumbar procedural group. This study identified that 40% of participants had never learned or experienced the ABCD time-out strategy and that 60% of surgeons did not use intraoperative navigation or imaging in their practices. The error has never been disclosed to the patient in 48% of the ICSS cases.

CONCLUSIONS: Due to a lack of application of safety checklist protocol, there is an increased occurrence of ICSS events in lower-income countries. The results of this study demonstrate the necessity of investing time and resources dedicated to avoiding preventable errors.

INTRODUCTION: Primary malignant melanoma of the spinal cord (PSM) is a rare condition with limited evidence regarding its diagnosis (clinical and radiographic), management, and prognosis. Our aim was to report an extremely rare two cases of primary malignant melanoma of the spine one of them is sacral melanoma which represents the second reported case in the literature and to conduct a systematic review of the relevant literature.

METHODS: The diagnosis and management of these cases were retrospectively reviewed. Using the PRISMA guideline, we conducted a systematic review of the literature to analyze different management strategies and the prognosis of such pathology.

RESULTS: All two patients were operated on, and received gross total removal of their tumors, with extended follow up for tumor recurrences. One of the cases involved a sacral tumor, which was resected without adjuvant therapy. The other one was seen by oncology and received post-operative chemo- and radio- therapy. In addition to the aforementioned cases, we present a comprehensive review of the literature on PSM from 1950 to the present, demonstrating that PSM is a very rare tumor, with a limited counted number of cases reported worldwide.

CONCLUSION: In conclusion, we report an exceedingly rare two cases of primary malignant melanoma of the spine. Early surgical intervention is key to the management of these rare and aggressive tumors. GTR should be attempted if possible.

INTRODUCTION: Primary malignant melanoma of the spinal cord (PSM) is a rare condition with limited evidence regarding its diagnosis (clinical and radiographic), management, and prognosis. Our aim was to report an extremely rare two cases of primary malignant melanoma of the spine one of them is sacral melanoma which represents the second reported case in the literature and to conduct a systematic review of the relevant literature.

METHODS: The diagnosis and management of these cases were retrospectively reviewed. Using the PRISMA guideline, we conducted a systematic review of the literature to analyze different management strategies and the prognosis of such pathology.

RESULTS: All two patients were operated on, and received gross total removal of their tumors, with extended follow up for tumor recurrences. One of the cases involved a sacral tumor, which was resected without adjuvant therapy. The other one was seen by oncology and received post-operative chemo- and radio- therapy. In addition to the aforementioned cases, we present a comprehensive review of the literature on PSM from 1950 to the present, demonstrating that PSM is a very rare tumor, with a limited counted number of cases reported worldwide.

CONCLUSION: In conclusion, we report an exceedingly rare two cases of primary malignant melanoma of the spine. Early surgical intervention is key to the management of these rare and aggressive tumors. GTR should be attempted if possible.

INTRODUCTION: Currently, there are only 3 reported cases of central nervous system malignancies in patients with Noonan syndrome in the literature, all of which are intracranial pathologies. To our knowledge, there are no cases of spinal cord glioblastoma multiforme reported in the literature.

CASE DESCRIPTION: We describe the case of a 12-year-old girl with Noonan syndrome who presented with back pain and new onset neurological deficits and was found to have a spinal cord lesion. T10-L1 laminoplasty with safe maximal resection was done. Postoperative pathological analysis identified this lesion as a high-grade astrocytoma consistent with glioblastoma multiforme.

CONCLUSIONS: Spinal cord glioblastoma multiforme is a rare occurrence in the general population, particularly in a patient with an underlying diagnosis of Noonan syndrome. Patients with spinal cord tumors can present with a multitude of clinical signs and symptoms and treatment should not be delayed.

OBJECTIVE: To report our experience using the scan-and-plan workflow and review current literature on surgical efficiency, safety, and accuracy of next-generation robot-assisted (RA) spine surgery.

METHODS: The records of patients who underwent RA pedicle screw fixation were reviewed. The accuracy of pedicle screw placement was determined based on the Ravi classification system. To evaluate workflow efficiency, 3 demographically matched cohorts were created to analyze differences in time per screw placement (defined as operating room [OR] time divided by number of screws placed). Group A had <4 screws placed, Group B had 4 screws placed, and Group C had >4 screws placed. Intraoperative errors and postoperative complications were collected to elucidate safety.

RESULTS: Eighty-four RA cases (306 pedicle screws) were included for analysis. The mean number of screws placed was 2.1 ± 0.3 in Group A and 6.4 ± 1.2 in Group C; 4 screws were placed in Group B patients. The accuracy rate (Ravi grade I) was 98.4%. Screw placement time was significantly longer in Group A (101 ± 37.7 minutes) than Group B (50.5 ± 25.4 minutes) or C (43.6 ± 14.7 minutes). There were no intraoperative complications, robot failures, or in-hospital complications requiring a return to the OR.

CONCLUSIONS: The scan-and-plan workflow allowed for a high degree of accuracy. It was a safe method that provided a smooth and efficient OR workflow without registration errors or robotic failures. After the placement of 4 pedicle screws, the per-screw time remained constant. Further studies regarding efficiency and utility in multilevel procedures are necessary.

OBJECTIVE: Multimodal intraoperative neuromonitoring (IOM) using somatosensory-evoked potentials and motor-evoked potentials is a sensitive and specific tool for detecting intraoperative neurologic injury during spine surgery. This study aimed to evaluate the use of multimodal IOM in a lower-middle-income country (LMIC) during cervical and thoracic spine surgery in order to prevent and predict new postoperative neurologic deficits early on. This is the first report of multimodal IOM application in LMICs.

METHODS: The neurophysiologist raised the cutoff warning criteria of 50 patients who underwent surgery for different cervical and thoracic pathologies to decrease postoperative neurologic deficits. We retrospectively reviewed the medical charts and neuromonitoring traces of these patients followed by calculating the sensitivity, specificity, positive predictive value, and negative predictive value of combined IOM for postoperative neurologic deficit occurrence.

RESULTS: A significant relationship was found between the reversibility of alerts and the development of new postoperative deficits (P < 0.001). There was no relationship between the cause of alerts and the reversibility of those alerts after corrective measures were carried out (P = 0.455), or the frequency of alerts and the development of new deficits postoperatively (P = 0.578). Sensitivity, specificity, positive predictive value, and negative predictive value of combined somatosensory-evoked potential and motor-evoked potential monitoring were 100%, 80%, 62.5%, and 100%, respectively.

CONCLUSION: Because of the limited experience and the many technical difficulties faced in LMICs, we found that this cutoff limit resulted in more false-positive warnings but helped to avoid any false-negative results, thus enhancing the safety of surgery.

OBJECTIVE: Multimodal intraoperative neuromonitoring (IOM) using somatosensory-evoked potentials and motor-evoked potentials is a sensitive and specific tool for detecting intraoperative neurologic injury during spine surgery. This study aimed to evaluate the use of multimodal IOM in a lower-middle-income country (LMIC) during cervical and thoracic spine surgery in order to prevent and predict new postoperative neurologic deficits early on. This is the first report of multimodal IOM application in LMICs.

METHODS: The neurophysiologist raised the cutoff warning criteria of 50 patients who underwent surgery for different cervical and thoracic pathologies to decrease postoperative neurologic deficits. We retrospectively reviewed the medical charts and neuromonitoring traces of these patients followed by calculating the sensitivity, specificity, positive predictive value, and negative predictive value of combined IOM for postoperative neurologic deficit occurrence.

RESULTS: A significant relationship was found between the reversibility of alerts and the development of new postoperative deficits (P < 0.001). There was no relationship between the cause of alerts and the reversibility of those alerts after corrective measures were carried out (P = 0.455), or the frequency of alerts and the development of new deficits postoperatively (P = 0.578). Sensitivity, specificity, positive predictive value, and negative predictive value of combined somatosensory-evoked potential and motor-evoked potential monitoring were 100%, 80%, 62.5%, and 100%, respectively.

CONCLUSION: Because of the limited experience and the many technical difficulties faced in LMICs, we found that this cutoff limit resulted in more false-positive warnings but helped to avoid any false-negative results, thus enhancing the safety of surgery.

BACKGROUND: Spontaneous intracranial hypotension (SIH) is a rare condition that can be very debilitating. SIH is well understood to be due to a CSF leak, however, identifying the source of the leak is still a challenge. We are presenting a case of Type 4 CSF leak and reviewing the related literature. CASE DESCRIPTION: A 46-year-old female presenting with intractable orthostatic headaches was diagnosed with SIH. She was unable to mobilize due to the severity of her symptoms. MRI scans of the brain and spine did not identify a source of the leak. After failing conservative therapy and multiple epidural blood patches, the patient underwent surgery which resulted in significant improvement in symptoms. CONCLUSION: This study has shown that surgical intervention improves symptoms in patients who do not have an identifiable source of CSF leak. Further studies need to be done to fully understand the role of surgery in Type 4 CSF leaks.