Bridging the gap between neuroimaging and neurosurgery: a case of epidural arteriovenous fistula with an intradural presentation. Illustrative case.

BACKGROUND: Epidural arteriovenous fistulas (eAVFs) are rare vascular malformations often mistaken for their intradural counterparts due to similar angiographic features. Differentiation between epidural and intradural vascular lesions is crucial as it impacts surgical planning and prognosis. Despite advancements in diagnostic imaging, these entities can be misinterpreted and challenge management. OBSERVATIONS: The authors report the case of a 68-year-old male suspected to have a type I dural arteriovenous fistula based on magnetic resonance angiography and angiographic evaluation. He presented with progressive myelopathy and multiple neurological symptoms exacerbated by recent trauma. A superselective angiogram of the right T10 segmental artery suggested an intradural arteriovenous fistula; however, intraoperatively, the lesion was epidural. The arterialized venous structures were obliterated, and the patient reported significant postoperative symptomatic improvement. LESSONS: This case highlights the critical importance of comprehensive imaging and cautious interpretation in the diagnosis of spinal vascular malformations. It also underscores the need for a multidisciplinary approach to ensure accurate diagnosis and effective treatment. Surgeons must be prepared for intraoperative findings that diverge from preoperative imaging to adapt surgical strategies accordingly. Furthermore, this case contributes to the evolving understanding of eAVFs, suggesting that revised imaging protocols may be required to better distinguish epidural from intradural vascular abnormalities. https://thejns.org/doi/10.3171/CASE24331.

Structure-sparing resection for the management of cervical chordomas: a retrospective institutional series.

OBJECTIVE: Chordomas are a rare and relatively slow-growing malignancy of notochordal origin with a nearly 50% recurrence rate. Chordomas of the cervical spine are particularly challenging tumors given surrounding vital anatomical structures. Although standard in other areas of the spine, en bloc resection of cervical chordomas is exceedingly difficult and carries the risk of significant postoperative morbidity. Here, the authors present their institutional experience with 13 patients treated with a structure-sparing radical resection and adjuvant radiation for cervical chordomas. METHODS: Records of the standing senior author and institutional database of spinal surgeries were retrospectively reviewed for surgically managed cervical and high thoracic chordomas between 1997 and 2022. Chordomas whose epicenter was cervical but touched the clivus or had extension to the thoracic spine were included in this series. Clinical and operative data were gathered and analyzed for the index surgery and any revisions needed. Outcome metrics such as recurrence rates, complication rates, functional status, progression-free interval (PFI) and overall survival (OS) were evaluated. RESULTS: The median patient age at diagnosis was 57 (range 32-80) years. The median modified Rankin Scale (mRS) score at the time of presentation was 1 (range 0-4). Approximately 40% of tumors were located in the upper cervical spine (occiput-C2). The median time from diagnosis to surgery was 74.5 (range 10-483) days. Gross-total resection was achieved in just under 40% of patients. All patients received adjuvant radiotherapy. The mean duration of follow-up was 4.09 years, with a mean PFI of 3.80 (range 1.16-13.1) years. Five patients experienced recurrence (38.5%). The mean OS was 3.44 years. Three patients died during the follow-up period; 2 due to disease progression and 1 died in the immediate postoperative period. One patient was lost to follow-up. A significant positive relationship was identified between high cervical tumor location and disease recurrence (p = 0.021). CONCLUSIONS: While en bloc resection is appropriate and feasible for tumors in the sacral spine, the cervical region poses a significant technical challenge and is associated with increased postoperative morbidity. Radical resection may allow for achievement of negative operative margins and, along with sparing postoperative morbidity following resection of cervical chordomas, maintaining a similar rate of recurrence when compared with en bloc resection while preserving quality of life.

Surgical Management of Thoracolumbar Adjacent Segment Disease: Techniques and Outcomes in 107 Patients Undergoing Surgical Intervention.

BACKGROUND: Adjacent segment disease (ASD) is a known sequela of thoracolumbar instrumented fusions. Various surgical options are available to address ASD in patients with intractable symptoms who have failed conservative measures. However, the optimal treatment strategy for symptomatic ASD has not been established. We examined several clinical outcomes utilizing different surgical interventions for symptomatic ASD. METHODS: A retrospective review was performed for a consecutive series of patients undergoing revision surgery for thoracolumbar ASD between October 2011 and February 2022. Patients were treated with endoscopic decompression (N = 17), microdiscectomy (N = 9), lateral lumbar interbody fusion (LLIF; N = 26), or open laminectomy and fusion (LF; N = 55). The primary outcomes compared between groups were re-operation rates and numeric pain scores for leg and back at 2 weeks, 10 weeks, 6 months, and 12 months postoperation. Secondary outcomes included time to re-operation, estimated blood loss, and length of stay. RESULTS: Of the 257 patients who underwent revision surgery for symptomatic ASD, 107 patients met inclusion criteria with a minimum of 1-year follow-up. The mean age of all patients was 67.90 ± 10.51 years. There was no statistically significant difference between groups in age, gender, preoperative American Society of Anesthesiologists scoring, number of previously fused levels, or preoperative numeric leg and back pain scores. The re-operation rates were significantly lower in LF (12.7%) and LLIF cohorts (19.2%) compared with microdiscectomy (33%) and endoscopic decompression (52.9%; P = 0.005). Only LF and LLIF cohorts experienced significantly decreased pain scores at all 4 follow-up visits (2 weeks, 10 weeks, 6 months, and 12 months; P < 0.001 and P < 0.05, respectively) relative to preoperative scores. CONCLUSION: Symptomatic ASD often requires treatment with revision surgery. Fusion surgeries (either stand-alone lateral interbody or posterolateral with instrumentation) were most effective and durable with respect to alleviating pain and avoiding additional revisions within the first 12 months following revision surgery. CLINICAL RELEVANCE: This study emphasizes the importance of risk-stratifying patients to identify the least invasive approach that treats their symptoms and reduces the risk of future surgeries.

Predictors of clinical and structural outcomes after surgery for spinal nerve sheath tumor resection: a retrospective analysis.

OBJECTIVE: Resection of spinal nerve sheath tumors (SNSTs) typically necessitates laminectomy, often with facetectomy, for adequate exposure of tumor. While removal of bone affords a greater operative window and extent of resection, it places the patient at greater risk for spinal instability. Although studies have identified risk factors for fusion at the time of tumor resection, there has yet to be a study assessing long-term stability following SNST resection. In this study, the authors sought to identify preoperative and operative risk factors that predispose to long-term spinal instability and investigate clinical variables associated with greater risk for subsequent fusion in the time following initial SNST resection. METHODS: An institutional registry of spinal surgeries was queried at a single institution over a 20-year period. Demographic, clinical, and operative variables were recorded retrospectively and investigated for predictive value of several postoperative sequelae. RESULTS: A total of 122 SNST cases among 112 patients were included. At a mean follow-up time of 27.7 months, patients with a history of neurofibromatosis type 2 (NF2) (p = 0.014) and those who had undergone a laminectomy of ≥ 4 levels at the time of initial SNST resection (p = 0.028) were more likely to present with some degree of structural abnormality or neurological deficit following their initial surgery. The presence of facetectomy, degree of laminectomy, and level of spinal surgery were not found to be predictors of future instability. Ultimately, there was no significant predictor for true spinal instability following index surgery without fusion. A secondary analysis showed that an entirely extradural location (p = 0.044) and facetectomy at index surgery (p = 0.012) were predictive of fusion being performed at the time of tumor resection. Four of the 112 patients required fusion after their index SNST resection, 3 of whom underwent fusion for instability at the level of the index surgery. No variables were identified as predictive for future instrumentation. CONCLUSIONS: Ultimately, the authors conclude that resection of SNSTs does not always necessitate fusion, and good outcomes can be obtained with motion-preserving techniques and minimizing facetectomy when possible. Patients with a history of NF2 and those with SNSTs that required ≥ 4-level laminectomy were more likely to exhibit some degree of structural abnormality and/or neurological deficit localized to the index level defined as either new or worsening spinal instability and/or new or worsening neurological deficit at last follow-up; however, no variable was found to be predictive of true spinal instability. Furthermore, a complete facetectomy at initial SNST resection and entirely extradural tumor location were noted to be associated with fusion at index surgery. Lastly, the authors were unable to identify a clinical predictor for future instrumentation.

Use of intraoperative topical antibiotics to reduce intrathecal baclofen pump surgical site infections: a single institution's experience over 24 years.

OBJECTIVE: Patients requiring intrathecal baclofen (ITB) therapy are at high risk for surgical site infections (SSIs) given their poor functional status. After years of a nominal infection rate, there was an inexplicable increase in ITB pump infections at the authors' institution and multiple investigations offered no solution. Use of intraoperative topical antibiotics is well-documented in the orthopedic literature and was considered for ITB pump insertion. In this study, the authors investigated whether intraoperative vancomycin and tobramycin powder at the ITB pump site could reduce SSIs. METHODS: Operative and infection data were collected and analyzed retrospectively to determine the efficacy of this change. Patients were stratified into three cohorts (1998-2009, 2010-2012, and 2013-2021) to better understand the trends before and after implementation of intraoperative topical antibiotics. Each cohort had similar demographics. RESULTS: One hundred fifty-four patients underwent 272 ITB pump procedures between 1998 and 2021 (131 in 1998-2009, 49 in 2010-2012, and 92 in 2013-2021) for cerebral palsy (69.5%), spastic quadriparesis due to traumatic brain injury (7.1%), anoxic brain injury (6.5%), and other causes (16.9%). Infection rates were reduced from a high of 32% in 2010-2011 to 3.8% over the last 2.5 years (p = 0.0094). There were no adverse effects from the use of topical antibiotics. CONCLUSIONS: In the setting of an intractable rise in ITB pump infections, the addition of intraoperative topical antibiotics significantly reduced postoperative infections in a high-risk population. One could appreciate a significant drop each year in the rate of infections after the institution of intraoperative topical antibiotics. The reduction in SSIs significantly improved the long-term outcomes for these patients.

Percutaneous Direct Pars Repair in Young Athletes.

BACKGROUND: Lumbar pars defects are common in adolescent athletes and are often due to recurrent axial loading and traumatic stressors. OBJECTIVE: To present an updated case series of young athletes who underwent percutaneous direct pars repair after failure of conservative management. METHODS: A single-center, nonrandomized, retrospective observation study of athletes who were referred for minimally invasive direct pars repair after failure of at least 6 months of conservative management was performed. Summary demographic information, clinical features of presentation, perioperative and intraoperative radiographic imaging, and visual analog scale back pain scores were collected and analyzed. RESULTS: A total of 21 patients were included (mean age [± SD] 17.47 ± 3.02 years, range 14-25 years), 6 of whom were female (29%). All patients presented with bilateral pars fractures, with L5 being the most frequent level involved (n = 13). The average follow-up time was 31.52 ± 9.38 months (range 3-110 months). The visual analog scale score for back pain was significantly reduced from 7.62 ± 1.83 preoperatively to 0.28 ± 0.56 at the final postoperative examination (P < .01). Fusion was noted in 20 of the 21 patients on final follow-up (95%). CONCLUSION: Percutaneous direct pars repair is a safe and effective means in treating young adolescents who have failed conservative management. The advantages included minimized muscle and soft tissue dissection, reduced blood loss, and early mobilization and recovery. In young athletes who desire return to high-level physical activity, this surgical technique is of particular benefit and should be considered in this patient population.

Transdural Approach for Resection of Craniovertebral Junction Cysts: Case Series.

BACKGROUND: Craniovertebral junction (CVJ) cysts, including retro-odontoid pseudotumors, are challenging pathologies to treat and manage effectively. Surgical intervention is indicated when these lesions result in progressive myelopathy, intractable pain, or instability. OBJECTIVE: To present a case series of older patients who underwent successful resection retro-odontoid lesions using transdural approach. METHODS: A single-center, retrospective observation study of older patients who underwent transdural resection of CVJ cysts at a single institution was performed. Summary demographic information, clinical presentation, perioperative and intraoperative imaging, and Nurick scores were collected and analyzed. RESULTS: Eight patients were included (mean age [±SD] 75.88 ± 9.09 years). All patients presented with retro-odontoid lesions resulting in severe cervical stenosis, cord compression, and myelopathy. The mean duration of surgery was 226 ± 83.7 minutes. The average intraoperative blood loss was 181.2 cc. The average hospital stay was 4.5 days ± 1.3 (range, 3-7 days). The average follow-up time was 12.5 ± 9.5 months. No intraoperative complications were encountered. The Nurick classification score for myelopathy improved at the final postoperative examination (2.38 ± 1.06 vs 1 ± 1.07). Three patients demonstrated a pre-existing deformity prompting an instrumented fusion. Both computed tomography and MRI evidence of complete regression of retro-odontoid cyst were noted in all patients on the final follow-up. CONCLUSION: Posterior cervical transdural approach for ventral lesions at the CVJ is a safe and effective means of treating older patients with progressive myelopathy. This technique provides immediate spinal cord decompression while limiting neurological complications commonly associated with open or endoscopic anterior transpharyngeal approaches.

Delayed subdural fluid collections after Ommaya reservoir placement.

BACKGROUND: Delayed subdural fluid collections can occur after Ommaya reservoir placement and can cause neurological symptoms and interfere with treatment. We performed a retrospective chart review to study risk factors for delayed subdural fluid collections and clinical outcomes. METHODS: Retrospective chart review was performed for patients undergoing Ommaya reservoir placement between 2010-2019 at our institution. RESULTS: Out of 53 patients who had Ommaya reservoir placement during the study period, 11 developed delayed subdural fluid collections (21%). HIV infection was the only statistically significant risk factor (P=0.001, Fisher's Exact Test). Thrombocytopenia, ventricle size, use of the reservoir, and suboptimal catheter placement were not associated with development of delayed subdural fluid collections. 2 patients, both HIV positive, required surgical evacuation. CONCLUSIONS: Delayed subdural fluid collections occur in a significant minority of patients after Ommaya reservoir placement, and some patients require surgical intervention. HIV infection is associated with a higher risk of development of delayed subdural fluid collections. This patient subpopulation may benefit from closer monitoring or adjustment of management protocols.

Diaphragmatic Hernia With Incarcerated Spleen as a Complication After Lateral Anterior Column Realignment.

BACKGROUND: The creation of sagittal balance of the spine is critical in the treatment adult spinal deformity. Anterior column release (ACR) has gained traction as a minimally invasive alternative to pedicle subtraction osteotomy. By releasing the anterior longitudinal ligament, the anterior column can be lengthened and physiologic lordosis restored. Risks such as transient psoas weakness and thigh numbness have been well documented in the literature; however, diaphragmatic hernia has never been reported. OBJECTIVE: To highlight the difficulties encountered in diagnosing, managing, and treating iatrogenic diaphragmatic hernia in the setting of ACR and stress the relevant retropleural, retroperitoneal, and diaphragmatic structures during the surgical approach. METHODS: In this technical note, we discuss the relevant anatomy in a direct lateral approach to the thoracolumbar junction and the management of an iatrogenic diaphragmatic hernia, which occurred in a patient who underwent a L1 ACR. RESULTS: Three months after surgery, our patient was assessed in clinic and endorsed significant improvements in her pain and mobility. Her 3-month postoperative scoliosis x-rays demonstrated a significant improvement in her sagittal alignment, and she experienced no further negative sequelae from the iatrogenic hernia. CONCLUSION: Iatrogenic diaphragmatic hernia with an intrathoracic spleen after direct lateral ACR is a risk spine surgeons should be aware of and address promptly.

Direct Bypass Surgery for Moyamoya and Steno-occlusive Vasculopathy: Clinical Outcomes, Intraoperative Blood Flow Analysis, Long-term Follow-up, and Long-term Bypass Patency in a Single Surgeon Case Series of 162 Procedures.

BACKGROUND: Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for the treatment of cerebral hypoperfusion secondary to chronic steno-occlusive vasculopathy. We sought to determine clinical outcomes, intraoperative blood flow analysis, long term follow up, and long term patency rates from a single surgeon's series of direct cerebral bypass for moyamoya disease, moyamoya syndrome, and steno-occlusive disease. METHODS: We reviewed clinical, demographic, operative and neuroimaging records for all patients who underwent a direct EC-IC bypass by the senior author between August 1999 and November 2020. Primary outcomes analyzed were functional long-term outcomes (by modified Rankin score [mRS]), surgical complications, and short-term and long-term bypass patency. RESULTS: A total of 162 revascularization procedures in 124 patients were performed. Mean clinical follow up time was 2 years 11 months. The combined immediate and long term postoperative stroke and/or intracerebral hemorrhage rate was 6.2%. There were 17 bypasses (10%) that were found to be occluded at long-term follow-up, all but one were asymptomatic. Long-term graft occlusion was correlated with presence of complete collateralization on preoperative angiography but not cut flow index (CFI). Overall, patients had a significant clinical improvement with a mean mRS score 1.8 preoperatively and 1.2 postoperatively. CONCLUSIONS: In our consecutive series of patients treated with direct EC-IC cerebral bypass, there was significant improvement in functional outcome as measured by the mRS. The long term patency rate was 90%. There was a statistically significant correlation between complete or incomplete angiographic collateralization patterns and long-term bypass occlusion. There was no correlation between bypass type, clinical syndrome, or CFI and long-term occlusions. The role of bypass surgery and the need for surgical expertise remain strong in the treatment of moyamoya variants and a select group of atherosclerotic steno-occlusive patients.

Microsurgical Management of Vestibular Schwannoma (Acoustic Neuroma): Facial Nerve Outcomes, Radiographic Analysis, Complications, and Long-Term Follow-Up in a Series of 420 Surgeries.

OBJECTIVE: The purpose of this study is to retrospectively evaluate the clinical and surgical outcomes of a large surgical series of vestibular schwannoma from North America over 20 years. METHODS: After institutional review board approval a retrospective review of the senior author's personal case logs to identify patients who had operations for vestibular schwannoma was performed. The clinical notes, operative record, preoperative and postoperative imagings, and long-term clinical follow-up notes were evaluated. RESULTS: A total of 415 patients who underwent 420 surgeries were identified from the years 1998-2021. The average length of follow-up was 3 years and 9 months. Overall, at last follow-up the rate of "good" facial nerve outcomes (House-Brackmann [HB] score I and II) was 86% and "poor" facial nerve outcomes (HB III-VI) was 14%. The amount of cerebellopontine angle extension (P = 0.023), tumor volume (P = 0.015), facial nerve consistency (P < 0.001), preoperative HB score (P < 0.001), and FN stimulation threshold at the end of the procedure (P < 0.001) were correlated to facial nerve function at the last follow-up. CONCLUSIONS: This study represents one of the largest recently reported surgical series of vestibular schwannoma in North American literature with available long term follow-up. Facial nerve outcomes correlated with cerebellopontine angle extension, tumor volume, facial nerve stimulation threshold, facial nerve consistency, preoperative facial nerve function, and history of a prior resection. Tumor recurrence remains significantly higher after subtotal resection. We believe the data supports a continuation of a strategy of general intent of gross total resection, greatly modifiable by intraoperative findings and judgment.

Conservative Management of Post-Operative Cerebrospinal Fluid Leak following Skull Base Surgery: A Pilot Study.

BACKGROUND/AIMS: Iatrogenic CSF leaks after endoscopic endonasal transsphenoidal surgery remain a challenging entity to manage, typically treated with CSF diversion via lumbar drainage. OBJECTIVE: To assess the safety and efficacy of high-volume lumbar puncture (LP) and acetazolamide therapy to manage iatrogenic CSF leaks. METHODS: We performed a prospective pilot study of four patients who developed iatrogenic postoperative CSF leaks after transsphenoidal surgery and analyzed their response to treatment with concomitant high-volume lumbar puncture followed by acetazolamide therapy for 10 days. Data collected included demographics, intra-operative findings, including methodology of skull base repair and type of CSF leak, time to presentation with CSF leak, complications associated with high-volume LP and acetazolamide treatment, and length of follow-up. RESULTS: Mean patient age was 44.28 years, with an average BMI of 27.4. Mean time from surgery to onset of CSF leak was 7.71 days. All four patients had resolution of their CSF leak at two- and four-week follow-up. Mean overall follow-up time was 179 days, with a 100% CSF leak cure rate at the last clinic visit. No patient suffered perioperative complications or complications secondary to treatment. CONCLUSION: Although our pilot case series is small, we demonstrate that a high-volume LP, followed by acetazolamide therapy for 10 days, can be considered in the management of post-operative CSF leaks.

Efficacy of Reverse and Modified Bohlman Technique for Lumbar Spondylolisthesis: A Systematic Review of the Literature.

OBJECTIVE: High-grade lumbar spondylolisthesis (HGLS) remains a challenging surgical entity, and there is no current consensus regarding optimal surgical approach. The purpose of this study was to systematically review the literature for studies utilizing the reverse or modified Bohlman technique for the treatment of HGLS to assess their safety and efficacy. METHODS: The authors performed a literature search of PubMed/MEDLINE electronic databases from their inception according to the PRISMA guidelines. RESULTS: A total of 8 studies were included. The studies comprised a total of 43 patients, with mean age of 41.4 ± 19.8 (range: 9-83) years. The mean follow-up was 38.2 ± 41.7 (range: 3-137) months. Most patients (81.4%) were classified as having grade III or higher spondylolisthesis. The most common presenting symptom was back pain (93%), followed by radiculopathy in roughly half of patients (41.9%). The majority of patients (93%) experienced complete resolution of symptoms as well as successful fusion (90.7%) on follow-up. Complications included cage/graft failure (7%), nerve injury (7%), wound infection (7%), pseudoarthrosis (2.3%), epidural hematoma (2.3%), and deep vein thrombosis (2.3%). Revision surgery was required in 4 (9.3%) patients. Slip percentage (60.2% vs. 43.2%, P < 0.0001) and slip angle (17.1° vs. 6.4°, P < 0.001) both decreased significantly following surgery. CONCLUSIONS: Our data demonstrate that reverse and modified Bohlman techniques appear to be effective in both improving slip angle/percentage and relieving symptoms with low risk of complications. These findings are limited by the small sample size of patients. The authors recommend larger series before formal recommendations can be made.

Fusiform Dilatation of the Internal Carotid Artery in Childhood-Onset Craniopharyngioma: A Systematic Review.

OBJECTIVE: Patients with fusiform dilatation of the carotid artery (FDCA) following pediatric craniopharyngioma resection typically have a benign clinical course. We reviewed the neurosurgical literature for FDCA outcomes after resection of these tumors. METHODS: Using PubMed, Web of Science, and Cochrane databases, we identified surgical series or case reports reporting incidences of FDCA following craniopharyngioma resection. Inclusion criteria included FDCA outcomes reported specifically after craniopharyngioma resection, with at least 6 months of follow-up data. RESULTS: Our literature search yielded 15 full-text articles comprising 799 patients (376 [52.3%] males). The weighted mean follow-up was 74.8 months (range, 9-140 months). Most tumors were suprasellar (62.1%), with traditional microsurgery being more commonly employed than endoscopic endonasal surgery (80.9% vs. 19.1%). Gross total resection was achieved in 42.6% of cases. There were 55 aneurysms reported, most commonly occurring at the terminal internal carotid artery (66.7%). Aneurysmal progression on follow-up occurred in 10 (18.5%) cases, with no reports of rupture. Ten (18.2%) aneurysms were treated with clipping, endovascular, or bypass techniques. CONCLUSIONS: FDCA is a rare complication following pediatric craniopharyngioma resection. The exact cause is unclear, and factors related to tumor invasiveness, size, location, and differences in surgical approach may contribute to FDCA development. Most patients who go on to develop FDCA have an innocuous course on follow-up, with no reports of rupture in the present literature. For this reason, patients rarely require surgical or endovascular intervention for these lesions, and conservative management is favored.

One-donor, two-recipient extracranial-intracranial bypass series for moyamoya and cerebral occlusive disease: rationale, clinical and angiographic outcomes, and intraoperative blood flow analysis.

OBJECTIVE: Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for ischemic vasculopathy. A previously described variation of this technique is to utilize one donor artery to supply two recipient arteries, which the authors designate as 1D2R. The purpose of this study is to present a single surgeon's series of 1D2R direct bypasses for moyamoya and ischemia using detailed clinical, angiographic, and intraoperative blood flow measurement data. To the authors' knowledge, this is the largest series reported to date. METHODS: Hospital, office, and radiographic imaging records for all patients who underwent cerebral revascularization using a 1D2R bypass by the senior author were reviewed. The patients' demographic information, clinical presentation, associated medical conditions, intraoperative information, and postoperative course were obtained from reviewing the medical records. RESULTS: A total of 21 1D2R bypasses were performed in 19 patients during the study period. Immediate bypass patency was 100% and was 90% on delayed follow-up. The mean initial cut flow index (CFI(i)) was 0.64 ± 0.33 prior to the second anastomosis and the mean final value (CFI(f)) was 0.94 ± 0.38 after the second anastomosis (p < 0.001). The overall bypass flow increased on average by 50% (mean 17.9 ml/min, range -10 to 40 ml/min) with the addition of the second anastomosis. There was no significant difference in the overall flow measurements when the end-to-side anastomosis or side-to-side anastomosis was performed first. There was a statistically significant difference in the proportion of patients with a modified Rankin Scale (mRS) score of 0 or 1 postoperatively compared to preoperatively (p < 0.01). Through the application of Poiseuille's law, the authors analyzed flow dynamics, deduced the component vascular resistances based on an analogy to electrical circuits and Ohm's law, and introduced the new concepts of "second anastomosis relative augmentation" and "second anastomosis sink index" in the evaluation of 1D2R bypasses. CONCLUSIONS: The application of the 1D2R technique in a series of 19 consecutive patients undergoing direct EC-IC bypass for flow augmentation demonstrated high patency rates, statistically significantly higher CFIs compared to 1D1R, and improved mRS scores at last clinical follow-up. Additionally, the technique allows a shorter dissection time and preserves blood flow to the scalp. The routine utilization of intraoperative volumetric flow measurements in such surgeries allows a deeper understanding of the hemodynamic impact on individual patients.

Augmented Reality Assisted Endoscopic Transforaminal Lumbar Interbody Fusion: 2-Dimensional Operative Video.

Augmented reality (AR) is a novel technology for spine navigation. This tracking camera-integrated head-mounted display (HMD) represents a novel stereotactic computer navigation modality that has demonstrated excellent precision and accuracy with spinal instrumentation.1 Standard computer-assisted spine navigation systems have two major shortcomings: attention shift and line-of-sight limitations. The HMD allows visualization of the surgical field and navigation data concurrently in the same field of view.2,3 However, the use of AR in spine surgery has been limited to use for instrumentation, not for endoscopy. Fully endoscopic transforaminal interbody fusion under conscious sedation is an effective treatment option for degenerative spondylolisthesis and spinal stenosis. Although this technique has a steep learning curve, the advantages are vast, including preservation of normal tissue, smaller incisional requirement, and reduced postoperative pain, all enabling rapid recovery after surgery. As with other endoscopic spine surgeries, this procedure has a steep learning curve and requires a robust understanding of foraminal anatomy in order to safely access the disc space.4,5 However, with the introduction of AR, the safety and precision of this procedure could be greatly improved upon. In this video, we present a case of a 60-yr-old female who presented with a grade 1 spondylolisthesis and severe spinal stenosis and was treated with an L4-L5 interbody fusion. All instrumentation steps and localization for the endoscopic portion of the case were performed with assistance from the AR-HMD system. Informed written consent was obtained from the patient. The participant and any identifiable individuals consented to the publication of his/her image.

Thoracolumbar Interfascial Plane Block and Transversus Abdominis Plane Block for Postoperative Analgesia: 2-Dimensional Operative Video.

While spinal fusion in properly selected patients has been shown to be effective in improving pain, function, and quality of life, many patients continue to have reservations regarding the historical morbidity associated with surgical intervention.1 Open lumbar fusion surgery traditionally is perceived as an intervention that is associated with significant pain, recovery time, and risk. Even though most patients ultimately recover from this procedure, they are often left scarred with the psychological, economic, and social costs.2 To combat these negative associations with spinal fusion, neurosurgeons have begun to adopt adjunctive treatment modalities, including thoracolumbar interfascial plane (TLIP) blocks and transversus abdominis plane (TAP) blocks to improve pain control and reduce postoperative opiate consumption.3,4 The TLIP block is done after the patient is intubated and prior to skin incision for our posterior lumbar cases. Recently, we have also begun placing TAP blocks for patients undergoing anterior lumbar interbody fusion (ALIF) using exclusively liposomal bupivacaine, as commonly practiced for other abdominopelvic surgeries, to lengthen the duration of analgesia.5 We have found that these blocks have ameliorated both intraoperative and postoperative pain management.6 In this video, we present a case of a 65-yr-old female who presented with a grade 1 spondylolisthesis and neuroforaminal compression from L4 to S1, who was treated with combined TAP and TLIP block followed by a L4 to S1 ALIF with posterolateral instrumentation. Informed written consent was obtained from the patient and her family.