C1 Laminectomy Research Articles

Symptomatic Multi-Nodular Fourth Ventricular Choroid Plexus Papillary Fibrosis in the Context of Chiari II Malformation: Case Report and Literature Review

Introduction: Chiari II malformation (CM-II) is a congenital malformation characterized by the caudal displacement of the cerebellar tonsils, inferior cerebellar vermis, and fourth ventricle through the foramen magnum. Although rare, the association between CM-II and the development of a variety of mass lesions within the fourth ventricle and craniocervical junction has been described in the literature. Case Presentation: We present the case of a 9-year-old boy with a history of mid-lumbar myelomeningocele, CM-II, and ventriculoperitoneal shunt-dependent hydrocephalus who was discovered to have a syringomyelia and numerous spherical/ovoid masses within the caudal fourth ventricle and dorsal cervicomedullary subarachnoid space on a surveillance brain MRI. On questioning, the patient endorsed a longstanding history of poor bilateral hand dexterity and grip strength. After further imaging workup, the patient underwent suboccipital craniectomy and C1 laminectomy for resection of the mass lesions arising from the fourth ventricular choroid plexus (CP) and performance of an expansile pericranial duraplasty. The patient tolerated surgery well and had progressive improvement in hand dexterity/strength as well as radiographic improvement in the cervical cord syrinx after surgery. Pathologic analysis of the resected mass lesions demonstrated the lesions to be predominantly characterized by dense nodular fibrosis of the CP stromal cores which we are describing as choroid plexus papillary fibrosis. A minority of the lesional stromal cores were noted to be edematous, imparting a more “reticular” appearance. There were no features to suggest a neoplastic or infectious process. Conclusion: This combination of dysplastic/reactive CP histologic findings has not been previously reported in an extramedullary location. The unique pathology of this patient’s CP lesions will be discussed, and previously reported fourth ventricular mass lesions seen in association with CM-II will be reviewed.

C1 root decompression as a therapeutic target in non-suboccipital non-Valsalva related headache associated with Chiari I malformation

Headache is the most common symptom impacting the quality of life of patients with Chiari I malformation. While headaches typically present in the occipital or suboccipital regions, and induced by Valsalva maneuver, complex migraine-like headaches referring to frontal or orbital regions also occur. Our study explores the therapeutic potential of C1 nerve root decompression in addition to increasing intracranial compliance in patients with Chiari I malformation. We retrospectively analyzed cases operated on for Chiari I malformation, focusing on patients with non-suboccipital, non-Valsalva induced headaches. Preoperative and postoperative visual analog scale (VAS) scores and headache frequency were recorded. Surgical technique involved suboccipital craniectomy, C1 laminectomy, cerebellar tonsil reduction, and C1 root decompression. Twelve patients (10 females, 2 males) aged 22-52 were included. Preoperative mean VAS score was 8, which improved to 2 or less in 11 patients postoperatively. The mean headache frequency decreased significantly. Our findings suggest that C1 root compression contributes to atypical headaches in Chiari I malformation and that C1 root decompression may improve surgical outcomes.

Efficacy and safety of laminoplasty combined with C3 laminectomy for patients with multilevel degenerative cervical myelopathy: a systematic review and meta-analysis.

Laminoplasty (LP) combined with C3 laminectomy (LN) can effectively achieve spinal cord decompression while maintaining the integrity of the posterior ligament-muscle complex, thereby minimizing cervical muscle damage. However, its necessity and safety remain controversial. This study aimed to compare the safety and efficacy of LP and LP combined with C3 LN in the treatment of patients with multilevel degenerative cervical spondylotic myelopathy (DCM). A systematic review and meta-analysis of the literature was performed. A search of PubMed, Web of Science, Embase, and the Cochrane Library databases was conducted from inception through December 2023 and updated in February 2024. Search terms included laminoplasty, laminectomy, C3 and degenerative cervical spondylosis. The literature search yielded 14 studies that met our inclusion criteria. Outcomes included radiographic results, neck pain, neurologic function, surgical parameters, and postoperative complications. We also assessed methodologic quality, publication bias, and quality of evidence. Fourteen studies were identified, including 590 patients who underwent LP combined with C3 LN (modified group, MG) compared to 669 patients who underwent LP (traditional group, TG). The results of the study indicated a statistically significant improvement in cervical range of motion (WMD = 3.62, 95% CI: 0.39 to 6.85) and cervical sagittal angle (WMD = 2.07, 95% CI: 0.40 to 3.74) in the MG compared to the TG at the last follow-up (very low-level evidence). The TG had a higher number of patients with complications, especially C2-3 bone fusion. There was no significant difference found in improvement of neck pain, JOA, NDI, cSVA, T1 slope at latest follow-up. LP combined with C3 LN is an effective and necessary surgical method for multilevel DCM patients to maintain cervical sagittal balance. However, due to the low quality of evidence in existing studies, more and higher quality research on the technology is needed in the future.

Exploring the atlantic part of the vertebral artery in the South Indian population and its implications in spine surgery.

A descriptive, quantitative cross-sectional study of the atlantic part (V3) of the vertebral artery (VA). This study aimed to bridge the research gap in the morphometry of the V3 segment of the VA in the South Indian population. The microsurgical anatomy of this segment of the VA has been explored in various populations, and a thorough understanding of the anatomy and course of the VA, particularly the V3 segment, is essential to prevent iatrogenic complications. Several computed tomography studies but a few cadaveric studies have explored the V3 segment of the VA in the South Indian population. This study examined 40 VAs from 20 embalmed cadavers that were obtained from the voluntary donation program, and Institutional Ethical Clearance was obtained before the study. The length, diameter, and angle of the vertical, horizontal, and exit parts of the V3 segment of the VA were documented after its exposure. The mean lengths of the right and left VAs on each part were nearly similar, except for the mean length of the horizontal part (right: 38.937 mm, left: 40.237 mm) and total length of the V3 segment (right: 66.870 mm, left: 70.350 mm). These morphometric parameters are essential to spine surgeons who intend to operate on a small part (vertical, horizontal, or exit part) of the V3 segment of the VA. The mean values of the parameters obtained in this study give average measurements or safe limits to surgeons for safe surgical procedures such as the occipital condyle screw technique and C1 laminectomy.

Cervicomedullary cavernous malformation of the C1 nerve root: illustrative case.

Cavernous malformations (CMs) originating from spinal nerve roots are rare but can present with rapidly progressing neurological deficits. Therefore, quick identification and treatment are essential. The authors present the case of a 52-year-old male presenting with headaches and gait disturbance, found to have a CM of the C1 nerve root. The patient underwent successful suboccipital craniectomy and C1 laminectomy, with complete resection of the lesion, preservation of the cervical spinal nerve roots, and symptomatic improvement postoperatively. This is the first presentation in the literature of a CM originating from the C1 nerve root. The authors show complete resection of the lesion with preservation of the C1 nerve root. Nerve root lesions usually show insidious symptomatic onset. Quick identification and resection are recommended to prevent permanent neurological disability. https://thejns.org/doi/10.3171/CASE2456.

Safety and Preliminary Efficacy of Cervical Paraspinal Interfascial Plane Block for Postoperative Pain after Pediatric Chiari Decompression.

Surgery for lesions of the posterior fossa is associated with significant postoperative pain in pediatric patients related to extensive manipulation of the suboccipital musculature and bone. In this study, we assess the preliminary safety, effect on neuromonitoring, and analgesic efficacy of applying a cervical paraspinal interfascial plane block in pediatric patients undergoing posterior fossa surgery. In this prospective case series, we enrolled five patients aged 2-18 years undergoing surgery for symptomatic Chiari type I malformation. An ultrasound-guided cervical cervicis plane (CCeP) block was performed prior to the incision. A local anesthetic agent (bupivacaine) and a steroid adjuvant (dexamethasone) were injected into the fascial planes between the cervical semispinalis capitis and cervical semispinalis cervicis muscles at the level of the planned suboccipital decompression and C1 laminectomy. Motor-evoked and somatosensory-evoked potentials were monitored before and after the block. Patients were assessed for complications from the local injection in the intraoperative period and for pain in the postoperative period. No adverse events were noted intraoperatively, and there were no changes in neuromonitoring signals. Pain scores were low in the immediate postoperative period, and rescue medications were minimal. No complaints of incisional pain or need for narcotics were noted at the time of the 3-month postsurgical follow-up. In this study, we demonstrate the preliminary safety and analgesic efficacy of a novel application of a CCeP block to pediatric patients undergoing suboccipital surgery. Larger studies are needed to further validate the use of this block in children.

Surgical resection of pediatric craniocervical junction Rosai-Dorfman histiocytosis-a case report and literature review.

Rosai-Dorfman disease (RDD) with craniocervical junction involvement is a rare clinical entity. We present herein a case of a pediatric patient with craniocervical junction RDD which was surgically treated. A 10-year-old female with a history of B-cell acute lymphoblastic leukemia (B-ALL) in remission and RDD presented with frontal migraine headaches. She previously had a right posterior chest wall lesion which was biopsy-proven RDD. She was found on imaging to have a dural-based right craniocervical junction lesion. Given her history of B-ALL, after a multidisciplinary discussion, the decision was made to proceed with resection with possible initiation of cobimetinib or clofarabine. The patient underwent a suboccipital craniotomy, C1 laminectomy, and resection of the dural-based lesion. Gross total resection was achieved, and histopathology confirmed the diagnosis of RDD. She was discharged home on postoperative day 4. No recurrence was seen on follow-up imaging at 3months. We conducted a systematic literature review examining all cases of pediatric intracranial RDD and all cases of craniocervical junction RDD. This represents, to the best of our knowledge, only the second case of pediatric craniocervical junction RDD. Although RDD is often self-limiting, medical treatment is often considered for intracranial disease, but tissue confirmation is necessary. Surgical resection provides histopathologic diagnosis and can sometimes serve as definitive treatment for a particular lesion.

Modified Atlantoaxial Arthrodesis Technique for Atlantoaxial Instability via Intraarticular Autografting Using Structural Iliac Bone: Technical Nuances and Case Series

ObjectiveThe present study described a modified technique of atlantoaxial arthrodesis in patients with atlantoaxial instability (AAI) along with the postoperative clinical and radiological results. MethodsFive patients underwent this method for their AAI concurrent with C1 arch hypoplasia and/or the development of odontoid pannus causing myelopathy. After thorough exposure of the posterior surface of the C1-2 complex, the bilateral C2 nerve roots were sectioned to allow for easier access to the C1/2 facet joints. To prepare a suitable grafting bed, the C1/2 facet capsule was opened, then the articular cartilaginous and synovial tissues were thoroughly removed. After being properly fashioned to match the gap between the C1/2 facet joint spaces, the structural bone grafts from the iliac crest were directly inserted into the facet joint spaces. To alleviate cord compression caused by concomitant odontoid pannus and/or hypoplastic C1 arch, C1 laminectomy was necessitated in all cases. Subsequently, posterior screw-rod instrumental fixation was conducted. ResultsAll five patients underwent this procedure successfully. Clinical and radiological follow-up data of all patients indicated favorable relief of clinical symptoms and early rigid C1-2 stability. The sequelae of C2 nerve resection were not remarkable. No other neural or vascular damage associated with this technique was observed. ConclusionModified atlantoaxial arthrodesis via intraarticular autografting using the structural iliac bone combined with posterior instrumentation appears to be an efficient alternative treatment method for AAI patients with concurrent pathologies, even when the C1-2 posterior arches are unavailable for the grafting bed.

Predictors of poor functional outcomes in adults with type I Chiari Malformation: Clinical and surgical factors assessed with the Chicago Chiari Outcome Scale over long-term follow-up

ObjectiveThis study aimed to identify clinical and surgical features associated with poor long-term postoperative outcomes in patients diagnosed with Type I Chiari Malformation (CMI) treated with posterior fossa decompression with duroplasty (PFDD), with or without tonsillar coagulation. MethodsThis retrospective, single-center study included 107 adult patients with CMI surgically treated between 2010 and 2021. The surgical technique involved a midline suboccipital craniectomy, C1 laminectomy, durotomy, arachnoid dissection, duroplasty, and tonsillar coagulation until 2014, after which tonsillar coagulation was discontinued. Postoperative outcomes were assessed using the Chicago Chiari Outcome Scale (CCOS) at a median follow-up of 35 months. Clinical, surgical, and neuroimaging data were analyzed using the Wilcoxon signed-rank test, Cox regression analysis, and Kaplan-Meier survival curves to identify predictors of poor functional outcomes. ResultsOf the 107 patients (mean age 43.9 years, SD 13), 81 (75.5 %) showed functional improvement, 25 (23.4 %) remained unchanged, and 1 (0.9 %) experienced worsened outcomes. Cephalalgia, bilateral motor weakness, and bilateral paresthesia were the most frequent initial symptoms. Tonsillar coagulation was performed in 31 cases (28.9 %) but was clinically associated with higher rates of unfavorable outcomes. The Wilcoxon signed-rank test indicated that long-term follow-up CCOS was significantly higher than postoperative CCOS (Z = −7.678, p < 0.000). Multivariate Cox analysis identified preoperative bilateral motor weakness (HR 6.1, 95 % CI 1.9–18.9; p = 0.002), hydrocephalus (HR 3.01, 95 % CI 1.3–6.9; p = 0.008), and unilateral motor weakness (HR 2.99, 95 % CI 1.1–8.2; p = 0.033) as significant predictors of poor outcomes on a long-term follow-up. ConclusionThis study highlights the high rate of functional improvement in CMI patients following PFDD. Preoperative motor weakness and hydrocephalus were significant predictors of poor long-term outcomes. Tonsillar coagulation did not demonstrate a clear clinical benefit and may be associated with worse outcomes. Our findings suggest that careful preoperative assessment and selection of surgical techniques are crucial for optimizing patient outcomes.

Evaluation of the Bone Union Occurring Subsequent to C1-2 Fusion Combined With C1 Laminectomy for the Surgical Treatment of Retro-Odontoid Pseudotumor.

Introduction Surgical treatments for retro-odontoid pseudotumors (ROPs) include C1 laminectomies and C1-2 and occipitocervical (OC) fusions. When a C1 laminectomy is combined with a C1-2 fusion, concerns arise regarding an increased risk of pseudarthrosis due to decreased bone grafting space. Extension of the fusion area to the OC region may be considered to ensure an adequate bone graft bed. However, this procedure is associated with a risk of complications. Thus, in this study, we investigated the bone fusion and clinical outcomes of C1-2 fusion combined with a C1 laminectomy. Methods Between January 2017 and December 2022, seven patients with ROPs who had undergone C1-2 fusion combined with a C1 laminectomy were included in the study. All patients were followed up for >1 year. Bone fusion was evaluated by computed tomography (CT) at one year postoperatively, while implant failure was assessed by radiography at the final follow-up. Clinical evaluations included preoperative and one-year postoperative Japanese Orthopaedic Association (JOA) scores and recovery rates. Results This study included five male and two female patients, with an average age of 71.9 years. The average follow-up duration was 3.3 years. The primary anchor choices included the C1 lateral mass screw and the C2 pedicle screw. In one case, the transarticular screw was utilized unilaterally, and in another case, a lamina screw was utilized unilaterally. One year postoperatively, CT revealed bone fusion in three of the seven patients. Fusion occurred at the lateral and median atlantoaxial joints in two cases and one case, respectively. Screw loosening was observed in one case. None of the patients required reoperations. The average JOA recovery rate was 34.6%. Conclusion This surgical technique is useful for stabilizing and decompressing the C1-2 region while preserving mobility at the OC joint. However, further long-term follow-up studies are required.

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

BackgroundChiari 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 post-operative discomfort and optimize outcomes. MethodsChiari type 1 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. Results10 patients were treated. Mean age was 43.3 years with 7 females. All patients presented 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) min, with mean blood loss of 88.5 (50-140) mL. 90% of patients were discharged the same surgical day (mean 7.2 [5.3-7.7] hours post-op). No immediate or delayed post-operative complications were evidenced. At 6-months, 90% of patients had mRS 0-1. At last follow-up the VAS mean was 1.5 (range 0-4, p<0.001). ConclusionThe 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 post-operative discomfort, reduce the risk of surgical site infections, and optimize outcomes.

What is the Preferable Method for the C3 and C7 Segments in Unilateral Open-Door Laminoplasty for Patients Diagnosed with Cervical Spondylotic Myelopathy?

BackgroundTraditional C3–C7 unilateral open-door laminoplasty (UOLP) often lead to various postoperative complications due to damage of cervical posterior muscles and nuchal ligaments. We aimed to thoroughly evaluate postoperative outcomes of following our modified UOLP versus traditional UOLP in treating multilevel cervical spondylotic myelopathy (MCSM). MethodsSeventy-six patients with MCSM who underwent the modified UOLP with C3 laminectomy and C7 upper hemi-laminectomy (40 patients) or traditional C3–C7 UOLP (36 patients) were included. Pre- and postoperative cervical radiological parameters, as well as clinical and surgical outcomes were evaluated. ResultsPostoperatively, JOA scores improved significantly in modified UOLP group than traditional UOLP group (P=0.028), while VAS scores and NDI scores improved similarly in both groups. Follow-up scores for JOA, NDI and VAS were not significantly different between two groups. At final follow-up, C2-7 sagittal vertical axis and T1 slope increased in traditional UOLP group and did not change in modified UOLP group and were unchanged in modified UOLP group. The C2−C7 Cobb angle decreased significantly in traditional UOLP group and did not change in modified UOLP group. The modified UOLP group lost less cervical posterior muscles area compared to traditional UOLP group (3.72±3.54%vs6.67±2.81%, P<0.001). The range of motion in modified UOLP group showed significantly greater than traditional UOLP group at final follow-up (P<0.001). Also, modified UOLP group experienced a notable reduction in operative time, blood loss volume, and postoperative hospital stay. ConclusionWe recommend performing our modified UOLP with C3 laminectomy and C7 upper hemi-laminectomy instead of traditional C3-C7 UOLP.

Anterolateral Foramen Magnum Meningioma: Case Report and Literature Review

Meningiomas are benign tumors dependent on arachnoid cells. Localization to the foramen magnum is rare and represents a surgical challenge. Surgical planning is crucial to choose an optimal approach and to avoid morbidity. We report a case of anterolateral meningioma of the craniocervical junction in a 49-year-old female patient with complaints of progressive weakness of the right arm for the past 6 months. Magnetic resonance imaging showed an extramedullary intradural tumor with dural insertion regarding the body of C1 vertebrae. The patient underwent surgery via suboccipital approach with a C1 laminectomy and a Simpson grade 2 resection was performed. The patient improved postoperatively and returned to her daily activities. We perform a literature review to discuss the considerations for the optimal surgical strategy for the approach of foramen magnum meningiomas.

Multilevel Laminoplasty for CSM: Is C3 Laminectomy Better Than C3 Laminoplasty at the Superior Vertebra?

In a multilevel cervical laminoplasty operation for patients with cervical spondylotic myelopathy (CSM), a partial or complete C3 laminectomy may be performed at the upper level instead of a C3 plated laminoplasty. It is unknown whether C3 technique above the laminoplasty affects loss of cervical lordosis or range of motion. Patients undergoing multilevel laminoplasty of the cervical spine (C3-C6/C7) at a single institution were retrospectively reviewed. Patients were divided into two cohorts based on surgical technique at C3: C3-C6/C7 plated laminoplasty ("C3 laminoplasty only", N = 61), C3 partial or complete laminectomy, plus C4-C6/C7 plated laminoplasty (N = 39). All patients had at least 1-year postoperative X-ray treatment. Of 100 total patients, C3 laminoplasty and C3 laminectomy were equivalent in all demographic data, except for age (66.4 vs. 59.4 years, p = 0.012). None of the preoperative radiographic parameters differed between the C3 laminoplasty and C3 laminectomy cohorts: cervical lordosis (13.1° vs. 11.1°, p = 0.259), T1 slope (32.9° vs. 29.2°, p = 0.072), T1 slope-cervical lordosis (19.8° vs. 18.6°, p = 0.485), or cervical sagittal vertical axis (3.1 cm vs. 2.7 cm, p = 0.193). None of the postoperative radiographic parameters differed between the C3 laminoplasty and C3 laminectomy cohorts: cervical lordosis (9.4° vs. 11.2°, p = 0.369), T1 slope-cervical lordosis (21.7° vs. 18.1°, p = 0.126), to cervical sagittal vertical axis (3.3 cm vs. 3.6 cm, p = 0.479). In the total cohort, 31% had loss of cervical lordosis >5°. Loss of lordosis reached 5-10° (mild change) in 13% of patients and >10° (moderate change) in 18% of patients. C3 laminoplasty and C3 laminectomy cohorts did not differ with respect to no change (<5°: 65.6% vs. 74.3%, respectively), mild change (5-10°: 14.8% vs. 10.3%), and moderate change (>10°: 19.7% vs. 15.4%) in cervical lordosis, p = 0.644. When controlling for age, ordinal regression showed that surgical technique at C3 did not increase the odds of postoperative loss of cervical lordosis. C3 laminectomy versus C3 laminoplasty did not differ in the postoperative range of motion on cervical flexion-extension X-rays (23.9° vs. 21.7°, p = 0.451, N = 91). There was no difference in postoperative loss of cervical lordosis or postoperative range of motion in patients who underwent either C3-C6/C7 plated laminoplasty or C3 laminectomy plus C4-C6/C7 plated laminoplasty.

NCMP-05. INTRACTABLE HEADACHE IN NEWLY DIAGNOSED AML WITH MIGRAINES AND CHIARI MALFORMATION- UNVEILING A COMPLEX SYMPTOM

Abstract Acute Myeloid Leukemia (AML) involvement in central nervous system (CNS) is poorly understood in pathophysiology, with reported incidence rates ranging from 1-33% of patients with relapsed AML. CNS involvement is uncommon in the early stages of AML. FLT3-ITD, chromosome 11 abnormalities, and inv(16) cytogenetics are known to have more potential to invade the CNS. A 28-year-old woman with recently diagnosed AML (FLT D835 mutation with deletion in the long arm of chromosome 11) and migraines was admitted for HIDAC consolidation #3. On day two, she started experiencing headaches in the bifrontal and bitemporal regions associated with photophobia, phonophobia, and nausea. Treatment for status migrainous provided little relief. MRI brain showed progression of Chiari malformation (CM) with tonsillar herniation from 16 to 19 mm, which precluded a lumbar puncture. On day 4, she was noted to have grade III papilledema and bilateral cranial nerve IV palsy with non-enhancing patchy increased FLAIR signal in dorsal pons, bilateral cerebral and middle cerebellar peduncles, without diffuse restriction on imaging. The patient underwent sub-occipital craniotomy and C1 laminectomy for decompression for chiari. On day 5, she developed cranial nerve palsies involving nerves VII, IV, and XII. Lumbar puncture (LP) performed after decompression demonstrated elevated opening pressure and 98% abnormal myeloid blast population, confirming CNS involvement of AML. 4 days before starting intrathecal chemotherapy, the patient was found to be in asystole (unclear etiology). This case highlights the range of differential diagnoses for headaches in a patient with multiple comorbidities, including obesity, migraine, Chiari malformation with tonsillar herniation, and cancer. It underscores the necessity for proactive screening of CNS invasion in AML patients with high-risk mutations and neurological symptoms. Moreover, it emphasizes the need to consider CNS involvement in AML patients with headaches, even if standard imaging does not show typical signs of leptomeningeal spread.

Optimal Treatment of C3 Lamina in Cervical Laminoplasty

Results of C4-C6 laminoplasty with C3 laminectomy and C3-C6 laminoplasty were compared retrospectively. To clarify the difference between C3 laminectomy and C3 laminoplasty in cervical laminoplasty. Intraoperative damage to the semispinalis cervicis has been shown to lead to postoperative axial symptoms and reduced range of motion (ROM). To prevent this event, C3 laminectomy in cervical laminoplasty is considered superior to C3 laminoplasty. A total of 36 patients were included in this study: 20 patients (GroupA) of C3 laminectomy, C4-C6 laminoplasty compared with 16 patients (GroupB) of C3-C6 laminoplasty. We collected patient's background data, operative time, Japanese Orthopaedic Association (JOA) score, VAS score, and radiologic findings such as C2-C7 Cobb angle, ROM, C2 inter-spinous angle, and use of postoperative PRN medication were compared. There was no statistically significant difference in the C2-C7 Cobb angles between the 2 groups before and after surgery (P= 0.315). In ROM, there was a 17.7% decrease from 31.5 preoperatively to 25.9 postoperatively in Group A, and a 6.1% decrease from 29.3 preoperatively to 27.5 postoperatively in Group B. There was no statistically significant difference in ROM (P= 0.683). Postoperative neck pain (VAS) was significantly lower in Group A than in Group B both at 1week (P= 0.015) and 1month (P= 0.035) after surgery. The C2 inter-spinous angle was statistically significantly smaller in Group A than in Group B (P= 0.004). Clinical outcomes and surgical outcomes did not differ significantly between groups. If the C2 interspinous angle is wide and intraoperative semispinalis capitis damage can be minimized, it is worth trying C3 laminoplasty, but if the C2 inter-spinous angle is narrow, C3 laminectomy is recommended from the beginning.

Prospective, Longitudinal Study of Clinical Outcome and Morphometric Posterior Fossa Changes after Craniocervical Decompression for Symptomatic Chiari I Malformation.

The time course of changes in posterior fossa morphology, quality of life, and neurologic function of patients with Chiari I malformation after craniocervical decompression requires further elaboration. To better understand the pace of these changes, we longitudinally studied patients with Chiari I malformation, with or without syringomyelia, before and after the operation for up to 5 years. Thirty-eight symptomatic adult patients (35 women, 3 men) diagnosed with Chiari I malformation only (n = 15) or Chiari I malformation and syringomyelia (n = 23) and without previous Chiari I malformation surgery were enrolled in a clinical study. Patients underwent outpatient study visits and MR imaging at 7 time points (ie, initial [before the operation], 3 months, 1 year, 2 years, 3 years, 4 years, and 5 years) during 5 years. The surgical procedure for all patients was suboccipital craniectomy, C1 laminectomy, and autologous duraplasty. Morphometric measurements demonstrated an enlargement of the CSF areas posterior to the cerebellar tonsils after the operation, which remained largely stable through the following years. There was a decrease in pain and improved quality of life after the operation, which remained steady during the following years. Reduction in pain and improved quality of life correlated with CSF area morphometrics. Most changes in MR imaging morphometrics and quality of life measures occurred within the first year after the operation. A 1-year follow-up period after Chiari I malformation surgery is usually sufficient for evaluating surgical efficacy and postoperative MR imaging changes.

Impact of C3 laminectomy on cervical sagittal alignment in cervical laminoplasty: a prospective, randomized controlled trial comparing clinical and radiological outcomes between C3 laminectomy with C4–C6 laminoplasty and C3–C6 laminoplasty

Background ContextC3 laminectomy in cervical laminoplasty is a modified laminoplasty technique that can preserve the semispinalis cervicis muscle attached to the C2 spinous process. Several previous studies have shown that this technique can lead to better outcomes of postoperative axial neck pain and C2–C3 range of motion (ROM) than conventional cervical laminoplasty. However, there is still a lack of understanding of total and proportional postoperative cervical sagittal alignment outcomes. PurposeTo assess the effects of C3 laminectomy in cervical laminoplasty on postoperative cervical alignment and clinical outcomes. DesignA single-center, patient-blinded, randomized controlled trial. Patient SampleWe included consecutive 126 patients diagnosed with cervical spondylotic myelopathy (CSM) or ossification of posterior longitudinal ligament (OPLL) who were scheduled for cervical laminoplasty from March 2017 to January 2020. Outcome MeasuresThe primary outcome measures were C2–C7 Cobb angle (CA) and neck disability index (NDI). Secondary outcomes measures included other clinical outcomes and radiographic parameters including segmental Cobb angle and presence of C2–C3 interlaminar fusion. MethodsPatients were randomly allocated to either the C3 laminectomy with C4–C6 laminoplasty group (LN group) or the C3–C6 laminoplasty group (LP group) at a 1:1 ratio. Laminoplasty was performed using a unilateral open-door technique and stabilized with titanium mini plates. A linear mixed model analysis was employed to examine the longitudinal data from postoperative 1-year through 3-year. Additional analysis between three types of cervical sagittal alignment morphology was done. ResultsAmong 122 patients who were randomly allocated to one of two groups (LN group, n=61; LP group, n=61), modified intent-to-treat analysis was done for 109 patients (LN group, n=51, LP group, n=58) who had available at least a year of postoperative data. Postoperative C2–C7 CA was not significantly different between the two groups. However, NDI was significantly different between the two groups (12.8±1.0 in the LN group vs 8.6±1.0 in LP group, p=.005), which exceeded the minimum clinically important difference (MCID). The postoperative C2–C3 CA was significantly greater in the LN group (7.1±0.5° in LN group vs 3.2±0.5° in LP group, p<.001) while C4–C7 CA was significantly smaller in the LN group (3.9±0.8° in LN group vs 7.7±0.7° in LP group, p<.001) with greater cSVA in the LN group (31.6±1.4 mm in LN group vs 25.5±1.3 mm in LP group at postoperative 3-year, p=.002). Postoperative Euro-Quality of Life-5 Dimension (EQ-5D), numerical rating scores for neck pain (NRS-N) were significantly better in the LP group than in the LN group (all p<.05) and only EQ-5D surpassed the MCID. The C2-C3 fusion rate was significantly different between the LN group (9.8%) and the LP group (44.8%) (p<.001). The LN group showed a higher prevalence of a specific cervical alignment morphology characterized by a sigmoid shape with proximal lordosis and distal kyphosis (S curve). This S curve demonstrated significantly unfavorable outcomes across multiple outcome variables. ConclusionThe impact of C3 laminectomy in cervical laminoplasty on postoperative kyphosis among patients with CSM or OPLL did not significantly differ from that of C3–C6 laminoplasty. However, C3 laminectomy in cervical laminoplasty might result in an unfavorable clinical outcome with an unbalanced cervical sagittal alignment characterized by a sigmoid shape with proximal lordosis and distal kyphosis.

P.128 Recurrent subarachnoid hemorrhage secondary to Chiari 1 malformation

Background: We describe a patient with recurrent subarachnoid hemorrhage (SAH) secondary to Chiari 1 malformation. Methods: A retrospective review of the clinical chart was performed. Results: A previously healthy female in her 70’s presented with worst headache of life. CT demonstrated 4th ventricular hemorrhage with SAH extending into the bilateral cerebellomedullary fissures. CTA did not show a vascular etiology and patient was discharged home. Incidental note was made of a right persistent trigeminal artery. The patient then represented 2 weeks later with worst headache of life and decreased level of consciousness. CT demonstrated extensive SAH extending into the 3rd and 4th ventricles. CTA and diagnostic cerebral angiogram did not show a vascular etiology. MRI brain/C-spine revealed Chiari 1 malformation. An external ventricular drain was placed but could not be weaned. She underwent suboccipital craniectomy with C1 laminectomy. Intraoperatively, there was a prominent dorsal spinal vein that appeared under tension as it pierced the arachnoid membrane and subsequently entering the dura as a rudimentary occipital sinus. This vein was coagulated and divided. The patient recovered well and was at neurological baseline at 6 month follow-up. Conclusions: This is the first reported case of recurrent SAH secondary to Chiari 1 malformation.

Resolution of a Focal Pruritic Rash Following Neurosurgical Decompression in an Adolescent With Chiari I and Syringomyelia

BackgroundChiari I malformation (Chiari I) is defined by the downward displacement of one or both cerebellar tonsils below the foramen magnum of the skull with crowding altering cerebrospinal fluid flow. It can be associated with the development of a fluid-filled cavity within the spinal cord, syringomyelia. Neurological deficits or symptoms can occur at the level of anatomic involvement of syringomyelia. Case PresentationA young man presented to dermatology clinic for evaluation of a pruritic rash. Recognizing a unique left “cape-like” distribution of neuropathic itch leading to prurigo nodularis, he was referred for further evaluation by neurology in the local emergency department. After additional history and neurological exam, a magnetic resonance imaging confirmed Chiari I with an associated syringobulbia and a syrinx extending to T10/11 of the spinal cord. Anteriorly the syrinx extended into the left parenchyma of his spinal cord involving the dorsal horn, a lesion explaining his neuropathic itch. The sensation of itch and rash resolved after posterior fossa craniectomy and C1 laminectomy with duraplasty. ConclusionNeuropathic itch, in addition to pain, can be a symptom of Chiari I with syringomyelia. Focal pruritus without an obvious cutaneous trigger should prompt providers to consider a central neurological pathology. While many patients with Chiari I are asymptomatic, the presence of neurological deficits and syringomyelia, are indications for neurosurgical evaluation.