Use of an intraoperative sodium oxychlorosene-based infection prevention protocol to safely decrease postoperative wound infections after spine surgery.

OBJECTIVE: Postoperative infection remains prevalent after spinal surgical procedures. Institutional protocols for infection prevention have improved rates of infection after spine surgery. However, prior studies have focused on only elective surgical patients. The aim of this study was to determine the efficacy of a multiinstitutional intraoperative sodium oxychlorosene-based infection prevention protocol for decreasing rate of infection after instrumented spinal surgery. METHODS: A retrospective analysis was performed at two tertiary care institutions with level I trauma programs, and patients who underwent posterior instrumented spinal fusion between January 1, 2011, and May 31, 2019, were included. Postoperative deep wound infection rates were captured before and after implementation of a multiinstitutional infection prevention protocol. Possible adverse outcomes related to infection prevention techniques were also examined. In addition, consecutive patients treated from January 1, 2018, to May 31, 2019, were prospectively included in a database to collect preoperative and postoperative spine-specific quality of life measures and to assess the impact of postoperative infection on quality of life. RESULTS: A total of 5047 patients fit the inclusion criteria. Of these, 1043 patients underwent surgery prior to protocol implementation. The infection rate of this cohort (3.5%) decreased significantly after protocol implementation (1.2%, p < 0.001). Postoperative sterile seroma rates did not differ between the preprotocol and postprotocol groups (0.7% vs 0.7%, p = 0.5). In the 1031 patients who underwent surgery between January 2018 and May 2019, the fusion rate was 89.2%. Quality of life outcomes between patients with infection and those without infection were similar, although statistical power was limited owing to the low rate of infection. Notably, 2 of 10 patients who developed deep wound infection died of infection-related complications. CONCLUSIONS: An intraoperative sodium oxychlorosene-based infection prevention protocol helped to significantly decrease the rate of infection after spine surgery without negatively impacting other postoperative procedure-related metrics. Postoperative wound infection may be associated with higher-than-expected rate of postoperative mortality.

Segments of the internal carotid artery during endoscopic transnasal and open cranial approaches: can a uniform nomenclature apply to both?

BACKGROUND: The classic anatomic view of the course of the internal carotid artery (ICA) and its segments familiar to neurosurgeons by a 3-dimensional microscopic cranial view may be challenging to understand when seen in the unique 2-dimensional view of transnasal endoscopic surgery. OBJECTIVE: We re-examined our 1996 classification of 7 (C1-C7) segments of the ICA, comparing the arterial course in cadaveric dissections for both a transnasal endoscopic transpenoidal approach and frontotemporal craniotomy. METHODS: Five formalin-fixed cadaveric heads injected with colored silicone underwent thin-cut computed tomographic scanning for bony and vascular analysis. The ICA's intracranial course viewed by transnasal endoscopic dissection was compared with the view of a bilateral frontotemporal crantiotomy, from the petrous (C2) to communicating (C7) segments. RESULTS: Refinement of our 1996 ICA classification provides an anatomical understanding for endoscopic exposures transnasally along an inferior skull base trajectory. The changing course of the ICA, initially termed loop is now termed bend (i.e., implying a change in direction). Four bends are described as the ICA enters into the skull base as C2, C3-C4, C4, and C4-C5. We discuss delineation of certain problematic ICA segments and identify landmarks for endoscopic endonasal approaches. CONCLUSIONS: Our classification of the segments of the ICA achieves consistency without sacrificing either clinical or anatomic accuracy for either transcranial or endoscopic approaches. Universal application of this established nomenclature can avoid new and misleading terms, respects anatomical landmarks delineating segments, and provides a universal language for clear communication between disciplines.

Atypical meningiomas: is postoperative radiotherapy indicated?

OBJECT: The role of postoperative radiation therapy after surgery for atypical meningiomas remains controversial. In this retrospective cohort study, the authors examine the recurrence rates for atypical meningiomas after resection (with or without adjuvant radiotherapy) and identify which factors were associated with recurrence. METHODS: Of 90 patients with atypical meningiomas who underwent surgery between 1999 and 2009, 71 (79%) underwent gross-total resection (GTR) and 19 (21%) underwent subtotal resection (STR); 31 patients received adjuvant radiotherapy. All tumors were pathology-confirmed WHO Grade II atypical meningiomas. Univariate and multivariate analyses were performed to identify factors associated with recurrence-free survival. RESULTS: Among 90 patients, 17 developed tumor recurrence (81% recurrence-free survival at 5 years). In the overall group, adjuvant radiotherapy reduced the recurrence rate to 9% from 19% at 5 years (p = 0.048). After STR, adjuvant radiotherapy significantly reduced recurrence from 91% to 20% (p = 0.0016). However, after GTR, adjuvant radiotherapy did not significantly reduce the recurrence rate (16.7% without radiation therapy vs 11.8% with radiation therapy) (p = 1.00). Five factors independently predictive of tumor recurrence included mitotic index, sheeting, necrosis, nonuse of radiation therapy, and STR. Further recursive partitioning analysis showed significant increases in risk for patients older than 55 years with mitoses and sheeting. CONCLUSIONS: Adjuvant radiotherapy was effective at lowering recurrence rates in patients after STR but delivered no significant improvement in patients after GTR. Given that rates after GTR were similar with or without adjuvant radiotherapy, close observation without postoperative radiation therapy may be a viable option for these patients. Patients older than 55 years and those with mitoses noted during pathological examination had a significant risk of recurrence after GTR; for these patients, postoperative radiotherapy is recommended.

Comparison of coil types in aneurysm recurrence.

OBJECTIVE: Coiling of saccular aneurysms may result in recurrence requiring retreatment. Aneurysm recanalization may depend on coil type. Coil variations include bare platinum, polymer coated (Matrix), and hydrophylic gel coated (HydroCoil) coils. The effect of coil type on aneurysm recurrence was evaluated. METHODS: Retrospective analysis of prospectively collected database of 100 consecutive, 4-15mm, coiled, ruptured aneurysms. There were 3 groups based on coil type: (1) bare platinum, (2) HydroCoil, and (3) Matrix. Data collected included age, gender, aneurysm location, follow-up, retreatments and angiographic occlusion and recanalization. RESULTS: There were 42.4% (n=14) anterior and 57.5% (n=19) posterior circulation aneurysms in the bare platinum, 61.5% (n=16) and 38.45% (n=10) in HydroCoil, and 43.9% (n=18) and 56.1% (n=23) in the Matrix groups. Retreatment was required in 4 (12.1%) bare platinum, 9 (21.9%) Matrix, and 3 (11.5%) HydroCoil groups. On follow-up angiography HydroCoil group had the most number of completely occluded and least number of residual aneurysms (P=0.01), HydroCoils showed the least (n=4), bare platinum an intermediate (n=7), and matrix group the greatest tendency (n=15) to recanalize. CONCLUSIONS: Matrix coils were most likely to need retreatment. Retreatment rates were comparable for bare platinum and HydroCoils. Follow-up angiography demonstrated statistically significant attenuation of residual aneurysms for HydroCoils. Matrix group had the greatest and HydroCoils the least tendency to recanalize. Factors other than coil surface-coating may attenuate aneurysm recurrence.

Muller's muscle, no longer vestigial in endoscopic surgery.

BACKGROUND: As a thin filmy covering overlaying the inferior orbital fissure (IOF), Muller's muscle was considered a vestigial structure in humans, and for this reason, its anatomical significance was neglected. Because of increasing interest in endonasal approaches to the skull base that encompasses this region, we re-examined this structure's role as an anatomical landmark from an endoscopic perspective. METHODS: In 10 cadaveric specimens, microanatomical dissections were performed (n = 5); endoscopic dissections were performed (n = 5) via approaches of the middle turbinate or inferior turbinate, and via the Caldwell-Luc approach through the maxillary sinus. Histological examinations were performed in 20 human fetuses (Embryology Institute, Universidad Complutense de Madrid, Madrid, Spain). RESULTS: In cadaveric dissections, Muller's muscle was demonstrated in all specimens, serving as a bridge-like structure that spanned the entire IOF and separated the orbit from the temporal, infratemporal, and pterygopalatine fossas. Depending on which endoscopic corridor was used, a different aspect of the IOF and Muller's muscle was identified. In our endoscopic and microscopic observations, Muller's muscle was extensive, not only spanning the IOF but also extending posteriorly to reach the superior orbital fissure (SOF) and anterior confluence of the cavernous sinus. Histological analysis identified many anastomotic connections between the ophthalmic venous system and pterygoid plexus that may explain how infection or tumor spreads between these regions. CONCLUSIONS: Muller's muscle serves as an anatomical landmark in the IOF and facilitates anatomical orientation in this region for endoscopic skull base approaches. Its recognition during endoscopic approaches allows for a better three-dimensional understanding of this anterior cranial base region.

Tethered cord syndrome: a review of the literature from embryology to adult presentation.

Tethered cord syndrome (TCS) is a clinical condition of various origins that arises from tension on the spinal cord. Radiographic findings may include the conus medullaris in a lower than normal position, fatty infiltration of the filum terminale, lipomyelomeningocele, myelomeningocele, myelocystocele, meningocele, split cord malformations, dermal sinus, anorectal malformations, and intraspinal tumors. The clinical constellation of signs and symptoms associated with TCS may include dermatologic, urological, gastrointestinal, neurological, and orthopedic findings. The current review focuses on TCS by age group of the more common causes of the condition, including myelomeningocele, lipomyelomeningocele, as well as the adult presentation of occult TCS. Pertinent review of the neuroembryology and normal anatomical position of the conus medullaris is included.

ARNT gene multiplicity in amphibians: characterization of ARNT2 from the frog Xenopus laevis.

The aryl hydrocarbon receptor nuclear translocator (ARNT) is a member of the Per-ARNT-Sim (PAS) protein superfamily, transcription factors that mediate the cellular responses to various developmental signals and environmental conditions. A beta-class ("partner") PAS protein, ARNT exhibits the capacity to form transcriptionally active heterodimers with several alpha-class ("sensor") proteins, including the aryl hydrocarbon receptors (AHRs), the hypoxia-inducible factors (HIFs), and the Single minded (Sim) proteins. Two genes encode different forms of ARNT in mammals: ARNT1, which is widely expressed, and ARNT2, which is limited to the brain and kidneys of adults and specific neural and branchial tissues of embryos. In contrast, fish apparently express only a single ARNT gene, although in different species, this may be either ARNT1 or ARNT2. In efforts to understand the evolution of ARNT proteins throughout the vertebrate lineage, we isolated an ARNT cDNA from early life stages of the amphibian Xenopus laevis. The encoded protein binds cognate DNA sequences in concert with mouse AHR. Phylogenetic analysis reveals that this sequence is orthologous to mammalian ARNT2 and paralogous to the recently reported X. laevis ARNT1. ARNT2 mRNA expression begins later than ARNT1 (stage 22 vs. stage 8), suggesting the two proteins play distinct roles during development. Hence, in the expression of two well-conserved ARNT paralogs with distinct expression patterns, X. laevis resembles mammals rather than fish. Diversity in the number and function of PAS proteins, including ARNT, may underlie significant species differences in developmental programming and biochemical response to environmental conditions. The identification of multiple amphibian ARNT paralogs represents an important step in the understanding of evolution and functional variation of ARNT in vertebrates.