Resection of intradural spinal lesions with concomitant instrumented fusion in children: a systematic review and representative cases

OBJECTIVE

More than one-third of pediatric patients who undergo resection of intradural spine lesions develop progressive postoperative deformity, with as many as half of these patients subsequently requiring surgical fusion. Intradural spinal procedures with simultaneous instrumented fusion in children, however, are infrequently performed. Moreover, the rationale for patient selection, outcomes, and safety of this single-stage surgery in children has not been systematically investigated. In this study, the authors review the practice of simultaneous intradural spinal resection and instrumented fusion in pediatric patients and provide two representative case examples from their institution.

METHODS

The authors searched the PubMed and Embase databases and performed a systematic review following the PRISMA protocol. Original articles of pediatric patients (age ≤ 18 years) who underwent intradural spine surgery, regardless of pathology, with concomitant instrumented fusion and reported outcomes were included. An institutional database of all spinal operations with instrumented fusion performed in patients aged ≤ 18 years over a 3-year period was screened to identify those who underwent intradural spine surgery with concomitant fusion.

RESULTS

Nine patients (median age 12 years) from 6 studies who underwent intradural lesion resection and concomitant fusion met inclusion criteria. Among all 11 patients included, primary rationales for concomitant fusion were extensive bone removal (i.e., corpectomy or total facetectomy, 73%), concerns for deformity in the setting of multilevel laminectomy/laminoplasty (18%), and severe baseline deformity (9%). The most represented pathology was neurenteric cyst (55%) followed by schwannoma (18%). Myxopapillary ependymoma, granular cell tumor, and pilocytic astrocytoma each were seen in 1 case. Seven patients (64%) underwent an anterior-approach corpectomy, tumor resection, and fusion, while the remaining 4 patients (36%) underwent a posterior approach. All patients with at least 1 year of follow-up cases achieved bony fusion. CSF leak and new-onset neurological deficit each occurred in 9% (1/11).

CONCLUSIONS

The rationales for performing single-stage intradural resection and fusion in pediatric patients in studies to date include the presence of severe baseline deformity, large extent of bone resection, and multilevel laminectomy/laminoplasty across cervicothoracic or thoracolumbar junctions. As current literature involving this cohort is limited, more data are needed to determine when concomitant fusion in intradural resections is appropriate in pediatric patients and whether its routine implementation is safe or beneficial.

An institutional experience in applying quality improvement measures to pituitary surgery: clinical and resource implications

OBJECTIVE

The aim of this study was to report the authors' experience developing a Lean Six Sigma clinical care pathway (CCP) for endoscopic endonasal transsphenoidal operations.

METHODS

Using Lean Six Sigma quality improvement principles-including the define, measure, analyze, improve, and control framework-the authors developed a CCP for endoscopic endonasal transsphenoidal operations, incorporating preoperative, intraoperative, and inpatient and outpatient postoperative phases of care. Efficacy and quality metrics were defined as postoperative length of stay (LOS), presentation to the emergency department (ED) or readmission within 30 days of discharge, and hospital charges. The study included all adult patients who underwent elective endoscopic endonasal resection for pituitary adenoma, Rathke's cleft cyst, craniopharyngioma, pituicytoma, or arachnoid cyst during the sampling period (April 1, 2018, to December 31, 2022).

RESULTS

Two hundred twenty-eight patients met criteria and were included; 94 were treated before and 134 were treated after implementation of the CCP. Differences between groups in age, gender, race, BMI, American Society of Anesthesiologists classification, geographic distribution, preoperative serum sodium, tumor size, adenoma functional status, and prior surgery were not significant. The mean postoperative LOS significantly decreased from 4.5 to 1.7 days following CCP implementation (p < 0.0001); LOS variability also decreased, with the standard deviation declining from 3.1 to 1.5 days. The proportion of patients discharged on postoperative day (POD) 1 significantly increased from 0% to 61.9% (p < 0.0001). Fewer than one-quarter of the patients (23.4%) were discharged by POD 2 prior to the CCP, while 88.8% of were discharged by POD 2 after CCP implementation (p < 0.0001). Rates of 30-day ED presentations or readmissions were not significantly different (2.1% vs 6.0%, p = 0.20, and 7.5% vs 6.7%, p > 0.99, respectively). Mean per-patient hospital costs declined from $38,326 to $26,289 (p < 0.0001), with an associated change in cost variability from a standard deviation of $16,716 to $12,498.

CONCLUSIONS

CCP implementation significantly improved LOS and costs of endoscopic endonasal resection, without adversely impacting postoperative ED presentations or readmissions.

Decision-Making in Clival Mass Lesions: Risk Factors for Malignant Disease and an Illustrative Case Example

Introduction  Clival tumors are rare and heterogeneous. Although some benign prototypical sellar lesions may present as clival tumors, the likelihood of malignant disease is higher. Here we define a novel algorithm for the workup and management of clival masses through an illustrative case of colorectal adenocarcinoma metastasis to the clivus. Methods  In this case report, the best practice guidelines for managing clival masses are described through a literature review and refined by senior author consensus. We conducted a focused systematic review to characterize the present case in the context of clival metastasis from gastrointestinal malignancy. Results  An 83-year-old woman presented with 4 weeks of headaches and blurry vision. Examination revealed partial right abducens and left oculomotor palsies. Magnetic resonance imaging (MRI) identified a large, weakly enhancing sellar and clival mass with sphenoid sinus extension. An aggressive subtotal endoscopic endonasal resection was performed with removal of all sphenoid, clival, and sellar disease without cavernous sinus wall resection. Pathology confirmed colorectal adenocarcinoma; computed tomography (CT) imaging identified an ascending colon mass with metastases to the liver and mesenteric nodes. Palliative oncologic therapies were recommended, but she elected hospice, and died 3 months after initial presentation. Gastrointestinal clival metastases are exceedingly rare among sellar and clival pathologies, with eight prior cases reported, most of which presented with diplopia from abducens nerve involvement. Conclusion  Clival masses are uncommon skull base lesions that are associated with more aggressive diseases. We present a consolidated framework for decision-making in these challenging patients, alongside an unusual case example that illustrates the importance of increased suspicion for malignant clinical entities in this setting.

Cognitive Heterogeneity Reveals Molecular Signatures of Age-Related Impairment

The greatest risk factor for cognitive decline is aging. The biological mechanisms for this decline remain enigmatic due, in part, to the confounding of normal aging mechanisms and those that contribute to cognitive impairment. Importantly, many individuals exhibit impaired cognition in age, while some retain functionality despite their age. Here, we establish a behavioral testing paradigm to characterize age-related cognitive heterogeneity in inbred aged C57BL/6 mice and reliably separate animals into cognitively ‘intact’ (resilient) and ‘impaired’ subgroups using a high-resolution home-cage testing paradigm for spatial discrimination. RNA sequencing and subsequent pathway analyses of cognitively stratified mice revealed molecular signatures unique to cognitively impaired animals, including transcriptional downregulation of genes involved in mitochondrial oxidative phosphorylation and sirtuin (Sirt1 and Sirt3) expression in the hippocampus. Mitochondrial function assessed using high-resolution respirometry indicated a reduced OXPHOS coupling efficiency in cognitively impaired animals with subsequent hippocampal analyses revealing an increase in the oxidative damage marker (3-nitrotyrosine) and an upregulation of antioxidant enzymes (Sod2, Sod1, Prdx6, etc). Aged-impaired animals also showed increased levels of IL-6 and TNF-α gene expression in the hippocampus and increased serum levels of pro-inflammatory cytokines, including IL-6. These results provide critical insight into the diversity of brain aging in inbred animals and reveal the unique mechanisms that separate cognitive resilience from cognitive impairment. Our data indicate the importance of cognitive stratification of aging animals to delineate the mechanisms underlying cognitive impairment and test the efficacy of therapeutic interventions.

Selective Ablation of Sod2 in Astrocytes Induces Sex-Specific Effects on Cognitive Function, d-Serine Availability, and Astrogliosis

Cognitive decline is a debilitating aspect of aging and neurodegenerative diseases such as Alzheimer's disease are closely associated with mitochondrial dysfunction, increased reactive oxygen species, neuroinflammation, and astrogliosis. This study investigated the effects of decreased mitochondrial antioxidant response specifically in astrocytes on cognitive performance and neuronal function in C57BL/6J mice using a tamoxifen-inducible astrocyte-specific knockout of manganese superoxide dismutase (aSOD2-KO), a mitochondrial matrix antioxidant that detoxifies superoxide generated during mitochondrial respiration. We reduced astrocyte SOD2 levels in male and female mice at 11-12 months of age and tested in an automated home cage (PhenoTyper) apparatus for diurnal patterns, spatial learning, and memory function at 15 months of age. aSOD2-KO impaired hippocampal-dependent spatial working memory and decreased cognitive flexibility in the reversal phase of the testing paradigm in males. Female aSOD2-KO showed no learning and memory deficits compared with age-matched controls despite significant reduction in hippocampal SOD2 expression. aSOD2-KO males further showed decreased hippocampal long-term potentiation, but paired-pulse facilitation was unaffected. Levels of d-serine, an NMDA receptor coagonist, were also reduced in aSOD2-KO mice, but female knockouts showed a compensatory increase in serine racemase expression. Furthermore, aSOD2-KO mice demonstrated increased density of astrocytes, indicative of astrogliosis, in the hippocampus compared with age-matched controls. These data demonstrate that reduction in mitochondrial antioxidant stress response in astrocytes recapitulates age-related deficits in cognitive function, d-serine availability, and astrogliosis. Therefore, improving astrocyte mitochondrial homeostasis may provide a therapeutic target for intervention for cognitive impairment in aging.SIGNIFICANCE STATEMENT Diminished antioxidant response is associated with increased astrogliosis in aging and in Alzheimer's disease. Manganese superoxide dismutase (SOD2) is an antioxidant in the mitochondrial matrix that detoxifies superoxide and maintains mitochondrial homeostasis. We show that astrocytic ablation of SOD2 impairs hippocampal-dependent plasticity in spatial working memory, reduces long-term potentiation of hippocampal neurons and levels of the neuromodulator d-serine, and increases astrogliosis, consistent with defects in advanced aging and Alzheimer's disease. Our data provide strong evidence for sex-specific effects of astrocytic SOD2 functions in age-related cognitive dysfunction.