A separate-dural-incision method of extradural dumbbell spinal schwannoma resection: cumulative experience at a single center.

OBJECTIVE: To present our experience in the surgical management of completely extradural dumbbell spinal schwannomas with a new surgical strategy. METHOD: This study is a case series of patients treated at the Neurosurgery Department of the First Affiliated Hospital of USTC, between January 2018 and June 2021. RESULTS: 24 patients met the inclusion criteria, with cervical and lumbar spines being the most frequent locations. All patients underwent surgical treatment. Total gross resection was accomplished in all patients. Two cases had numbness and no case exhibited motor deficit. There was no postoperative CSF leakage or wound infection. CONCLUSION: Based on a limited number of observations, we conclude that our technique was feasible and effective for the treatment of extradural dumbbell spinal schwannomas. CLINICAL TRIAL: http://www.chictr.org.cn/ , No. ChiCTR2400086171.

Dural arteriovenous fistulas in the falx cerebri: case series and literature review.

Dural arteriovenous fistulas (DAVFs) within the falx cerebri are infrequently documented and may be linked with the falcine sinus/venous plexus. The falcine sinus/venous plexus, often regarded as a normal venous structure, can exhibit pathological characteristics, differing from the persistent fetal falcine sinus. A retrospective analysis was conducted at a single center to identify all cases of DAVFs within the falx cerebri spanning from 2002 to 2022. Demographic data, fistula features, treatment modalities, clinical outcomes, and fistula closure were collected and analyzed. Additionally, relevant literature on DAVFs in this location was reviewed. Ten cases were identified at our center, supplemented by 13 cases reported in the literature. In our cohort, patients had an average age of 49.4 ± 8.1 years, with a male predominance of 90%. Trans-arterial embolization (TAE) alone achieved immediate complete occlusion in eight cases, while conservative treatment was pursued in two cases. No treatment-related complications or fistula recurrences were observed. In the literature, seven patients underwent direct surgery, three underwent TAE, and one underwent both direct surgery and radiosurgery for complete fistula closure. No instances of fistula recurrence or treatment complications were reported. Dural arteriovenous fistulas within the falx cerebri are rare, with limited literature available. They typically present as aggressive lesions. Treatment options include direct surgery or TAE. However, due to a lack of long-term DSA follow-up, the cure and recurrence rates are unknown for endovasdcular therapy. Further investigation is warranted to elucidate the involvement of the falcine sinus/venous plexus in falx cerebri DAVFs.

Subdural Extra-arachnoid Hygroma Because of Occult Distal Durotomy After Minimally Invasive Decompression: A Case Report.

CASE: We present the case of a 59-year-old man who had MIS L4-5 decompression. He presented the next day with intractable back and leg pain. Magnetic resonance imaging revealed ventral displacement of the cauda equina and a subdural collection on the right L3/L4 nerve roots. Revision decompression revealed occult durotomy caudal and contralateral to the index decompression. CONCLUSION: Minimally invasive spine (MIS) surgery leverages shorter operative time and reduced postoperative pain. Yet, decreased exposure can make identification and management complications challenging. This report highlights occult durotomy and spinal subdural extra-arachnoid hygroma in patients with postoperative nerve compression after seemingly uncomplicated MISS.

Oral bacterial genic expression detection in aneurysm wall of a French population sample - preliminary monocentric study.

INTRODUCTION: The etiology of brain aneurysms remains poorly understood. Finnish research suggests that oral bacteria might contribute to the development and rupture of brain aneurysms. Previous studies by our team have not confirmed these findings, likely due to methodological differences. We aimed to replicate the Finnish study with a French population, using the same primers and comparing the results to internal controls. METHODS: We used RT-qPCR to retrospectively analyze the expression of oral bacterial genes in eight patients. During surgical procedures, four tissue types were consistently sampled from each patient: the aneurysmal wall, the superficial temporal artery (STA), the middle meningeal artery (MMA), and the dura mater (DM). Results were expressed as fold differences employing the 2-∆∆Ct method, and statistical analyses were performed accordingly. RESULTS: Our cohort included eight patients, evenly split into ruptured and unruptured groups. The sex distribution was balanced (4 females, 4 males). We observed DNA expression from oral bacteria in all sampled tissues; however, there were no significant differences between the ruptured and unruptured groups. CONCLUSION: We detected oral bacterial gene expression in the aneurysmal wall, STA, MMA, and DM in a sample of French patients. Although limited by the small sample size, our results suggest a potential role for bacterial involvement in vascular invasiveness related to bacteremia. These findings do not definitively link oral bacteria to the pathogenesis of aneurysm development and rupture.

[Clinical analysis of resection and dura skull base reconstruction of cranionasal communication tumor in 31 cases].

Objective:To explore the methods of resection, dura and skull base repair and reconstruction of cranionasal communication tumor. Methods:Data of 31 patients with cranionasal communication tumor who underwent dura and skull base reconstruction after tumor resection from 2018 to 2022 were collected. Follow-up lasted for 3 to 41 months. Results:A total of 31 patients were enrolled, including 20 males and 11 females. The ages ranged from 19 to 74 years, with a median age of 57 years old. There were 17 benign lesions（one case of hemangioma, one case of Rathke cyst, one case of squamous papilloma, one case of craniopharyngioma, two cases of meningocele, two cases of varus papilloma, two cases of meningioma of grade Ⅰ, three cases of schwannoma, four cases of pituitary tumor） and 14 malignant lesions（one case of osteosarcoma, one case of poorly differentiated carcinoma, two cases of varus papilloma malignancy, two cases of olfactory neuroblastoma, two cases of adenocarcinoma, two cases of adenoid cystic carcinoma, four cases of squamous cell carcinoma） . Sixteen cases underwent nasal endoscopy combined with craniofacial incision and 15 cases underwent nasal endoscopy surgery alone. Complete resection of the mass and dura and skull base reconstruction were performed in all 31 patients, and free graft repair was performed in 8 cases（fascia lata in 5 cases and nasal mucosa in 3 cases）. Twenty-three cases were repaired with pedicled flaps（septal mucosal flap alone in 11 cases, septal mucosal flap combined with free graft in 6 cases, and cap aponeurosis combined with free graft in 6 cases）. Eight out of 31 patients underwent skull base bone repair. Postoperative cerebral hemorrhage occurred in 1 case, cerebrospinal fluid leakage in 1 case, intracranial infection in 2 cases. All patients were successfully treated without severe sequelae. Cerebrospinal fluid leakage and intracranial infection occurred in one patient after radiotherapy, who recovered after conservative treatment. All 17 patients with benign lesions survived. Thirteen out of 14 patients with malignant lesions received radiotherapy after surgery, nine survived without recurrence, five cases recurred, of which 2 survived with tumor, one underwent reoperation and 2 died. Conclusion:Cranionasal communication tumors are high-risk diseases of anterior and middle skull base, and various surgical repair methods could be selected after complete resection of the tumor. Successful reconstruction and multidisciplinary cooperation are crucial for treatment outcome.

[Clinical Evaluation of Dural (Spinal) Membrane Repair Materials].

Objective: To select high-quality and cost-effective dural (spinal) membrane repair materials, in order to reduce the cost of consumables procurement, save medical insurance funds, and optimize hospital operation and management. Methods: Taking the BS06B disease group (spinal cord and spinal canal surgery without extremely severe or severe complications and comorbidities, mainly diagnosed as congenital tethered cord syndrome) as an example, a retrospective analysis was conducted on the relevant data of surgical treatment for congenital tethered cord syndrome conducted in our hospital from January 2021 to June 2023. Safety and efficacy indicators in clinical application (incidence of postoperative epidural hemorrhage, incidence of postoperative purulent cerebrospinal meningitis, incidence of cerebrospinal fluid leakage, surgical duration, and postoperative hospital stay) were compared. Results: There was no difference in safety and effectiveness between different brands of dura mater repair materials. Conclusion: For the repair of small incisions in dura mater surgery, high-quality and cost-effective dura mater repair materials can be selected to reduce hospital costs and control expenses for the disease group.

A robust and biodegradable hydroxyapatite/poly(lactide-co-ε-caprolactone) electrospun membrane for dura repair.

Typically occurring after trauma or neurosurgery treatments, dura mater defect and the ensuing cerebrospinal fluid (CSF) leakage could lead to a number of serious complications and even patient's death. Although numerous natural and synthetic dura mater substitutes have been reported, none of them have been able to fulfill the essential properties, such as anti-adhesion, leakage blockage, and pro-dura rebuilding. In this study, we devised and prepared a series of robust and biodegradable hydroxyapatite/poly(lactide-co-ε-caprolactone) (nHA/PLCL) membranes for dura repair via an electrospinning technique. In particular, PLLA/PCL (80/20) was selected for electrospinning due to its mechanical properties that most closely resembled natural dural tissue. Studies by SEM, XRD, water contact angle and in vitro degradation showed that the introduction of nHA would destroy PLCL's crystalline structure, which would further affect the mechanical properties of the nHA/PLCL membranes. When the amount of nHA added increased, so did the wettability and in vitro degradation rate, which accelerated the release of nHA. In addition, the high biocompatibility of nHA/PLCL membranes was demonstrated by in vitro cytotoxicity data. The in vivo rabbit dura repair model results showed that nHA/PLCL membranes provided a strong physical barrier to stop tissue adhesion at dura defects. Meanwhile, the nHA/PLCL and commercial group's CSF had a significantly lower number of inflammatory cells than the control groups, validating the nHA/PLCL's ability to effectively lower the risk of intracranial infection. Findings from H&E and Masson-trichrome staining verified that the nHA/PLCL electrospun membrane was more favorable for fostering dural defect repair and skull regeneration. Moreover, the relative molecular weight of PLCL declined dramatically after 3 months of implantation, according to the results of the in vivo degradation test, but it retained the fiber network structure and promoted tissue growth, demonstrating the good stability of the nHA/PLCL membranes. Collectively, the nHA/PLCL electrospun membrane presents itself as a viable option for dura repair.

Inadequate Spinal Anesthesia in Lumbar Spine Surgery Is Related to Volume of the Thecal Sac.

BACKGROUND: Spinal anesthesia (SA) is used in lumbar surgery, but initial adequate analgesia fails in some patients. In these cases, spinal redosing or conversion to general endotracheal anesthesia is required, both of which are detrimental to the patient experience and surgical workflow. METHODS: We reviewed cases of lumbar surgery performed under SA from 2017-2021. We identified 12 cases of inadequate first dose and then selected 36 random patients as controls. We used a measurement tool to approximate the volume of the dural sac for each patient using T2-weighted sagittal magnetic resonance imaging sequences. RESULTS: Patients who had an inadequate first dose of anesthesia had a significantly larger dural sac volume, 22.8 ± 7.9 cm3 in the inadequate dose group and 17.4 ± 4.7 cm3 in controls (P = 0.043). The inadequate dose group was significantly younger, 54.2 ± 8.8 years in failed first dose and 66.4 ± 11.9 years in controls (P = 0.001). The groups did not differ by surgical procedure (P = 0.238), level (P = 0.353), American Society of Anesthesia score (P = 0.546), or comorbidities. CONCLUSIONS: We found that age, larger height, and dural sac volume are risk factors for an inadequate first dose of SA. The availability of spinal magnetic resonance imaging in patients undergoing spine surgery allows the preoperative measurement of their thecal sac size. In the future, these data may be used to personalize spinal anesthesia dosing on the basis of individual anatomic variables and potentially reduce the incidence of failed spinal anesthesia in spine surgery.

Preventing Post-incisional Dural Shrink in Craniotomy: Introducing the "Roll-up Technique".

Dural dryness makes suturing difficult during dural closure after craniotomy. In this case, dural plasty is often performed using a membrane taken from the surrounding tissue (e.g., fascia or periosteum) or an artificial replacement membrane. Herein, we introduce our novel "roll-up technique" to reduce the utilization of substitute membranes and explore its effectiveness in dural closure. We retrospectively examined the medical records of 50 patients who underwent craniotomy for the first time for supratentorial intracranial lesions between 2015 and 2022. Furthermore, we divided them into two groups: (1) the conventional technique group, which consisted of patients in whom the dura mater was flipped after incision and protected with a moistened gauze (n = 23), and (2) the roll-up technique group, which consisted of patients in whom the dura mater was incised in a U shape, rolled up, and protected with a moist gauze (n = 27). After surgery, we compared the success rates of primary closure, operating time, craniotomy area, and percentage of complications (e.g., cerebrospinal fluid [CSF] leakage or infection) between the groups. Dural closure without dural substitutes using the roll-up technique had a higher success rate than that using the conventional technique (26/27 [96.3%] cases vs. 14/23 [60.9%] cases; P = 0.003). Postoperative CSF leakage or infection did not occur, and no statistically significant difference was observed in the operating time between the groups (P = 0.247). The roll-up technique for dural closure may effectively prevent post-incisional dural shrink after craniotomy.

Application of Dural Suturing in Reconstruction of Sellar Floor for Cerebrospinal Fluid Leakage During Neuroendoscopic Intranasal Approach Surgery: A Meta-Analysis.

AIM: To assess the safety and efficacy of utilizing dural suturing as an adjunctive procedure for saddle floor reconstruction in patients undergoing endoscopic surgery in the sellar region. MATERIAL AND METHODS: According to the PRISMA guidelines, we searched the literature on sellar floor reconstruction in endoscopic sellar surgery. Fixed- or random-effects meta-analysis was used to pool the rate of return to postoperative cerebrospinal fluid (poCSF) leakage, repair operations, postoperative hospitalization, complete resection, infection, lumbar drainage (LD), and operative duration. RESULTS: A total of six studies involving 723 participants were included in the current meta-analysis. The pooled results demonstrated that patients in the dural suturing group had a lower incidence of poCSF leakage [odds ratio (OR), 0.18; 95% confidence interval (CI), 0.07 - 0.44; p=0.0002] and repair operation [OR, 0.24; 95% CI, 0.07 - 0.78; p=0.02], as well as a shorter hospitalization period [standardized mean difference (SMD), -0.45; 95% CI, -0.62 - -0.28; p < 0.00001]. There was no significant difference between the two groups in terms of the complete resection [OR, 1.06; 95% CI, 0.62 - 1.80; p=0.84], postoperative infection [OR, 0.49; 95% CI, 0.21 - 1.15; p=0.10] and lumbar drainage (LD) [OR, 0.28; 95% CI, 0.06 - 1.23; p=0.09]. Additionally, the dural suturing group may require a longer operative duration [SMD, 0.29; 95% CI, 0.02 - 0.56; p=0.03]. CONCLUSION: The results suggest that dural suturing can be advantageous in reducing postoperative complications and shortening postoperative hospitalization following neuroendoscopic surgery in the sellar region without increasing the risk of infection.

Effect of dural puncture epidural block technique on fetal heart rate variability during labor analgesia.

PURPOSE: To explore the effect of dural puncture epidural (DPE) block technique on fetal heart rate variability (HRV) during labor analgesia. METHODS: Sixty full-term primiparas who were in our hospital from April 2021 to October 2021 were selected and randomized into epidural analgesia (CEA) and dural puncture epidural analgesia (DPEA) groups (n = 30). After a successful epidural puncture, routine epidural catheter (EC) was performed in CEA group, and spinal anesthesia needle (as an EC) was used to puncture the dura mater to subarachnoid space in DPE group. Anesthetics were injected through EC. The time when the temperature sensation plane reached T10 (W1) and visual analog pain score (VAS), baseline heart rate score, amplitude variation score, cycle variation score, acceleration score, deceleration score, and total score of the first contraction after W1 were recorded. Apgar scores at 1 min, 5 min, and 10 min of neonates after delivery were recorded. RESULTS: The onset time of anesthesia in CEA group was significantly longer than that in DPEA group (p < .05). However, there are no significant differences in W1, VAS, baseline heart rate score, amplitude variation score, cycle variation score, acceleration score, deceleration score, and total score of the first contraction after W1 between the two groups (p > .05). Moreover, the Apgar scores at 1 min, 5 min and 10 min of neonates after delivery were not notably different between the two groups (p > .05). CONCLUSION: Compared with CEA, DPE block technique in labor analgesia relieves maternal pain without adverse effects on fetal HRV and newborns.

Lateral Spinal CSF Leaks in Patients with Spontaneous Intracranial Hypotension: Radiologic-Anatomic Study of Different Variants.

BACKGROUND AND PURPOSE: Spinal CSF leaks cause spontaneous intracranial hypotension. Several types of leaks have been identified, and one of these types is the lateral dural tear. Performing myelography with the patient in the decubitus position allows precise characterization of these leaks. The purpose of the current study was to describe the different variants of spontaneous lateral CSF leaks. MATERIALS AND METHODS: This retrospective cohort study included a consecutive group of patients with spontaneous intracranial hypotension and lateral CSF leaks who underwent digital subtraction myelography in the decubitus position and underwent surgery to repair the CSF leak between July 2018 and June 2023. RESULTS: The mean age of the 53 patients (37 women and 16 men) was 35.5 years. Three different variants of lateral CSF leak could be identified. Forty-nine patients (92.5%) had a lateral dural tear associated with the nerve root sleeve. The dural tear was at the axilla of the nerve root sleeve in 36 patients (67.9%) and at the shoulder in 13 patients (24.5%). Four patients (7.5%) had a lateral dural tear at the level of the pedicle that was not associated with the nerve root sleeve. Findings on digital subtraction myelography were concordant with intraoperative findings in all patients. An extradural CSF collection was seen in all patients with a lateral dural tear associated with the nerve root sleeve but in only 2 of the 4 patients with the pedicular variant of a lateral dural tear. CONCLUSIONS: We identified 3 variants of spontaneous lateral dural tears. Most lateral dural tears are associated with extradural CSF collections and arise from either the axilla (67.9%) or the shoulder (24.5%) of the nerve root sleeve. Lateral dural tears at the level of the pedicle (7.5%) not associated with the nerve root sleeve are uncommon and may require specialized imaging for their detection.

Intentional Dural Resection during en bloc Spinal Resection Could Provide a Secure Surgical Margin for Patients with Recurrent Spinal Tumors.

OBJECTIVE: It is always difficult to obtain a comfortable surgical margin for patients with recurrent malignant or invasive benign spinal tumors. Tumor intraspinal invasion and dural adhesion are the essential reasons. There are always residual tumor cells maintained at the edge of dura. Dural resection is a key point to obtain a comfortable surgical margin for such cases. Whether such patients benefit from this risky surgical procedure is unknown. This study aims to understand better the oncological results, associated risks, and neurological function of this risky surgical procedure. METHODS: We retrospectively reviewed clinical data from six consecutive patients who registered spinal tumors in our institute and underwent dural resection during en bloc spinal resection from June 2013 to May 2020. The demographic and perioperative data, oncological outcomes, complications, and neurological status were collected and analyzed. RESULTS: All six patients were followed up for 24 to 46 months (mean follow-up time: 32.8 months). Local recurrence was detected in one patient (1/6, 16.7%) at 36 months postoperatively and in five patients with no evidence of disease at the last follow up (survival rate 83.3%). Eleven complications occurred in four patients (66.7%), and the dural resection-related complications included only four cases of cerebrospinal fluid leakage (CSFL), which accounted for 36.4% (4/11) of all complications. Neurologic status evaluated by the Frankel grade showed improvement of one grade in one case and deterioration of one to two grades in five patients immediately after surgery. All deterioration cases recovered to the preoperative level 6 months after the operation. CONCLUSION: Dural resection is significant for patients with dura matter invaded by recurrent primary malignant or invasive benign spinal tumors with the purpose of clinical cure. This study demonstrated that in strictly selected cases, intentional dural resection could provide satisfying local control and long-term disease-free survival with acceptable complications and satisfying neurological function.

A novel computed tomography scoring system for evaluating the risk of dural defects in anterior surgery for cervical ossification of the posterior longitudinal ligament.

OBJECTIVE: To develop and validate a computed tomography (CT)-based scoring system for evaluating the risk of dural defects (DDs) in anterior surgery for cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: We retrospectively analyzed CT imaging features of 114 OPLL patients in our institute who received anterior decompression surgery. Intraoperative DDs were found in 16 patients. A multivariable logistic regression was used to evaluate the predictors. According to the odd ratio of the included risk factors, we developed a CT scoring system for evaluating the risk of DDs in anterior OPLL surgery. The system was further validated in an independent group of 39 OPLL patients. RESULTS: We developed a CT scoring system as follows: hook sign (2 points), K-line (-) (1 point) and broad base (1 point). Thus, the system comprised 4 total points, and patients were at high risks of dural defects when the score ≥3 points. The operating characteristics of a score ≥3 for predicting DDs in the validation group were: sensitivity of 0.83, specificity of 0.94, LR positive of 13.75, LR negative of 0.18 and AUC of 0.886. The discriminatory ability of the proposed score could be demonstrated in the validation cohort. CONCLUSIONS: The relatively simple and easy-to-use scoring system we propose integrates the 3 most reliable spinal CT findings observed in patients with OPLL and a DD. The likelihood to identify the underlying risks of spinal CSF leaks may be useful to triage patients who may benefit from indirect decompression techniques.

"The novel dura substitute: a revolutionary advancement in neurosurgery".

This Article provides a concise summary of the comprehensive exploration into the dura mater, dural tears, and the groundbreaking medical device, ArtiFascia® Dura Substitute. The neuroanatomy of the dura mater is elucidated, emphasizing its resilience and susceptibility to tears during spinal surgery. Dural repair methods are scrutinized, with research findings revealing the efficacy of primary closure with or without a patch.The introduction of ArtiFascia®, a nanofiber-based resorbable dural repair graft, represents a pivotal moment in neurosurgery. Obtaining 510(k) clearance from the FDA, ArtiFascia® demonstrates exceptional biological benefits, including enhanced cellular adhesion and tissue regeneration. The device's safety is affirmed through chemical analysis and toxicological risk assessment.The NEOART study, a randomized clinical trial involving 85 subjects across prominent European medical centers, validates ArtiFascia®'s superiority over existing dural substitutes. Noteworthy findings include exceptional graft strength, durability, and its ability to withstand physiological pressures.In conclusion, ArtiFascia® marks a revolutionary era in neurosurgery, promising safer and more effective solutions. This innovative device has the potential to elevate standards of care, offering both patients and surgeons an improved experience in navigating the complexities of neurosurgical procedures. The abstract encapsulates the key elements of the research, emphasizing the transformative impact of ArtiFascia® in the field.

[Venous Anatomy of the Superior and Inferior Sagittal Sinuses].

The superior sagittal sinus(SSS)is contained within the dura, which consists of the dura propria and osteal dura at the junction of the falx cerebri, in addition to the attachment of the falx to the cranial vault. The SSS extends anteriorly from the foramen cecum and posteriorly to the torcular Herophili. The superior cerebral veins flow into the SSS, coursing under the lateral venous lacunae via bridging veins. Most of the bridging veins reach the dura and empty directly into the SSS. However, some are attached to the dural or existed in it for some distance before their sinus entrance. The venous structures of the junctional zone between the bridging vein and the SSS existed in the dura are referred to as dural venous channels. The SSS communicates with the lateral venous lacunae connecting the meningeal and diploic veins, as well as the emissary veins. These anatomical variations of the SSS are defined by the embryological processes of fusion and withdrawal of the sagittal plexus and marginal sinus.

An autologous duraplasty in situ technique in the treatment of Chiari malformation Type I: a prospective study.

OBJECTIVE: Our study aims to prospectively compare an autologous duraplasty in situ technique (IS group) with the synthetic dural graft duraplasty (SDG group) to clarify the effectiveness and superiority of the former in the treatment of patients with Chiari malformation type 1 (CM-I). METHOD: 29 patients with CM-I were randomly assigned to either IS or SDG group. In both groups, a dissection from the occipital bone was performed. All procedures were performed by the same surgeon. The two duraplasty methods were compared in terms of surgical factors and complications. Data analysis was done for the baseline material, the neurological outcome and MRI-documented syrinx size at the 6 month follow-up. RESULT: 29 patients were enrolled in this study, 14 in the IS group and 15 in the SDG group. The results showed no significant difference in operation time (P = 0.916), amount of bleeding (P = 0.120), operation complications, hospitalization time (P = 0.854) and prognosis between the two groups. The hospitalization cost of IS group was 15,125 yuan less than that of SDG group (P < 0.05). CONCLUSION: The autogenous duraplasty in situ technique is a novel, simple, effective and economical surgical management for patients with CM-I.

Automatic segmentation of dura for quantitative analysis of lumbar stenosis: A deep learning study with 518 CT myelograms.

BACKGROUND: The diagnosis of lumbar spinal stenosis (LSS) can be challenging because radicular pain is not often present in the culprit-level localization. Accurate segmentation and quantitative analysis of the lumbar dura on radiographic images are key to the accurate differential diagnosis of LSS. The aim of this study is to develop an automatic dura-contouring tool for radiographic quantification on computed tomography myelogram (CTM) for patients with LSS. METHODS: A total of 518 CTM cases with or without lumbar stenosis were included in this study. A deep learning (DL) segmentation algorithm 3-dimensional (3D) U-Net was deployed. A total of 210 labeled cases were used to develop the dura-contouring tool, with the ratio of the training, independent testing, and external validation datasets being 150:30:30. The Dice score (DCS) was the primary measure to evaluate the segmentation performance of the 3D U-Net, which was subsequently developed as the dura-contouring tool to segment another unlabeled 308 CTM cases with LSS. Automatic masks of 446 slices on the stenotic levels were then meticulously reviewed and revised by human experts, and the cross-sectional area (CSA) of the dura was compared. RESULTS: The mean DCS of the 3D U-Net were 0.905 ± 0.080, 0.933 ± 0.018, and 0.928 ± 0.034 in the five-fold cross-validation, the independent testing, and the external validation datasets, respectively. The segmentation performance of the dura-contouring tool was also comparable to that of the second observer (the human expert). With the dura-contouring tool, only 59.0% (263/446) of the automatic masks of the stenotic slices needed to be revised. In the revised cases, there were no significant differences in the dura CSA between automatic masks and corresponding revised masks (p = 0.652). Additionally, a strong correlation of dura CSA was found between the automatic masks and corresponding revised masks (r = 0.805). CONCLUSIONS: A dura-contouring tool was developed that could automatically segment the dural sac on CTM, and it demonstrated high accuracy and generalization ability. Additionally, the dura-contouring tool has the potential to be applied in patients with LSS because it facilitates the quantification of the dural CSA on stenotic slices.

Minimally Invasive Technique for Chiari I Decompression Without Durotomy: Surgical Technique and Preliminary Case Series.

BACKGROUND: Chiari I malformation, marked by severe headaches and potential brainstem/spinal cord issues, often requires surgical intervention when conservative methods fail. This study introduces a minimally invasive surgery (MIS) Chiari decompression technique utilizing a 3-blade retractor, aiming to reduce postoperative discomfort and optimize outcomes. METHODS: Chiari type I malformation patients who underwent a MIS technique were included. Technique consisted of a minimal-soft tissue opening using a 3-blade retractor, suboccipital craniectomy, C1 laminectomy, and resection of the atlantooccipital band without a durotomy. RESULTS: Ten patients were treated. Mean age was 43.3 years, with 7 female patients. All patients presented with occipital headaches; 50% retroorbital pain; 40% neck, upper back, or shoulder pain; and 30% limb paresthesias. Median pre-surgical modified Rankin Scale (mRS) was 3 (2-4) and pain visual analog score (VAS) was 7 (5-9). Mean operative time was 59 (59-71) minutes, with mean blood loss of 88.5 (50-140) mL. In our sample, 90% of patients were discharged the same surgical day (mean 7.2 [5.3-7.7] hours postoperative). No immediate or delayed postoperative complications were evidenced. At 6 months, 90% of patients had mRS 0-1. At last follow-up the mean VAS was 1.5 (range: 0-4, P < 0.001). CONCLUSIONS: The MIS 3-blade flexible retractor technique for Chiari decompression is feasible, provides wide visualization angles of the suboccipital region and C1 arch, allows 2-surgeon work, and minimizes skin and soft tissue disruption. This combination may diminish postoperative discomfort, reduce the risk of surgical site infections, and optimize outcomes.