Postoperative Adjacent Segment Disease in Minimally Invasive Transforaminal Lumbar Interbody Fusion with Adjacent Laminectomy for Grade I-II Spondylolisthesis and Adjacent Spinal Stenosis.

BACKGROUND AND OBJECTIVES: Studies have demonstrated increased risk of adjacent segment disease (ASD) after open fusion with adjacent-level laminectomy, with rates ranging from 16%-47%, potentially related to disruption of the posterior ligamentous complex. Minimally invasive surgical (MIS) approaches may offer a more durable result. We report institutional outcomes of simultaneous MIS transforaminal lumbar interbody fusion (MISTLIF) and adjacent-level laminectomy for patients with low grade spondylolisthesis and ASD. METHODS: Retrospective analysis was performed on patients who underwent MISTLIF with adjacent level laminectomy to treat grade I-II spondylolisthesis with adjacent stenosis at a single institution from 2007-2022. RESULTS: A total of 34 patients met criteria, with mean follow-up of 23.1 months. In total, 37 levels were fused and 45 laminectomies performed. In this group, 21 patients received a single level laminectomy and single-level MISTLIF, 10 patients received a 2-level laminectomy and single-level MISTLIF, 2 patients received a single-level laminectomy and 2-level MISTLIF, and 1 patient received a 2-level laminectomy and 2-level MISTLIF. Three (8.8%) patients experienced clinically significant postoperative ASD requiring reoperation. Three other patients required reoperation for other reasons. Multiple logistic regression did not reveal any association between development of ASD and surgical covariates. CONCLUSION: MISTLIF with adjacent-level laminectomy demonstrated a favorable safety profile with rates of postoperative ASD lower than published rates after open fusion and on par with the published rates of ASD from MISTLIF alone. Future prospective studies may better elucidate the durability of adjacent-level laminectomies when performed alongside MISTLIF, but retrospective data suggests it is safe and durable.

Risk factors for C5 palsy: a systematic review and multivariate analysis.

OBJECTIVE: Postoperative C5 palsy (C5P) is a known complication in cervical spine surgery. However, its exact pathophysiology is unclear. The authors aimed to provide a review of the current understanding of C5P by performing a comprehensive, systematic review of the existing literature and conducting a critical appraisal of existing evidence to determine the risk factors of C5P. METHODS: A systematic search of PubMed/MEDLINE (January 1, 2019, to July 2, 2021), EMBASE (inception to July 2, 2021), and Cochrane (inception to July 2, 2021) databases was conducted. Preestablished criteria were used to evaluate studies for inclusion. Studies that adjusted for one or more of the following factors were considered: preoperative foraminal diameter (FD) at C4/5, posterior spinal cord shift at C4/5, preoperative anterior-posterior diameter (APD) at C4/5, preoperative spinal cord rotation, and change in C2-7 Cobb angle. Studies were rated as good, fair, or poor based on the Quality in Prognosis Studies (QUIPS) tool. Random effects meta-analyses were done using methods outlined by Cochrane methodologists for pooling of prognostic studies. Overall quality (strength) of evidence was based on Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methods for prognostic studies. The protocol for this review was published on the PROSPERO (CRD264358) website. RESULTS: Of 303 potentially relevant citations of studies, 12 met the inclusion criteria set a priori. These works provide moderate-quality evidence that preoperative FD substantially increases the odds of C5P in patients undergoing posterior cervical surgery. Pooled estimates across 7 studies in which various surgical approaches were used indicate that the odds of C5P approximately triple for each millimeter decrease in preoperative FD (OR 3.05, 95% CI 2.07-4.49). Preoperative APD increases the odds of C5P, but the confidence is low. Across 3 studies, each using different surgical approaches, each millimeter decrease in preoperative APD was associated with a more than 2-fold increased odds of C5P (pooled OR 2.51, 95% CI 1.69-3.73). Confidence that there is an association with postoperative C5P and posterior spinal cord shift, change in sagittal Cobb angle, and preoperative spinal cord rotation is very low. CONCLUSIONS: The exact pathophysiological process resulting in postoperative C5P remains an enigma but there is a clear association with foraminal stenosis, especially when performing posterior procedures. C5P is also related to decreased APD but the association is less clear. The overall quality (strength) of evidence provided by the current literature is low to very low for most factors. Systematic review registration no.: CRD264358 (https://www.crd.york.ac.uk/prospero/).

The Evolving Role of Postgraduate Year 7 in Neurological Surgery Residency.

BACKGROUND AND OBJECTIVES: In 2013, all neurosurgery programs were mandated to adopt a 7-year structure. We sought to characterize how programs use the seventh year of training (postgraduate year 7 [PGY7]). METHODS: We surveyed all accredited neurosurgery programs in the United States regarding the PGY7 residents' primary role and the availability of enfolded fellowships. We compiled responses from different individuals in each program: chair, program director, program coordinator, and current chiefs. RESULTS: Of 120 accredited neurological surgery residency programs within the United States, 91 (76%) submitted responses. At these programs, the primary roles of the PGY7 were chief of service (COS, 71%), enfolded fellowships (EFF, 18%), transition to practice (10%), and elective time (1%). Most residencies have been 7-year programs for >10 years (52, 57%). Sixty-seven programs stated that they offer some form of EFF (73.6%). The most common EFFs were endovascular (57, 62.6%), spine (49, 53.9%), critical care (41, 45.1%), and functional (37, 40.7%). These were also the most common specialties listed as Committee on Advanced Subspecialty Training accredited by survey respondents. Spine and endovascular EFFs were most likely to be restricted to PGY7 (24.2% and 23.1%, respectively), followed by neuro-oncology (12, 13.2%). The most common EFFs reported as Committee on Advanced Subspecialty Training accredited but not restricted to PGY7 were endovascular (24, 26.4%) and critical care (23, 25.3%). CONCLUSION: Most accredited neurological surgery training programs use the COS as the primary PGY7 role. Programs younger in their PGY7 structure seem to maintain the traditional COS role. Those more established seem to be experimenting with various roles the PGY7 year can fill, including enfolded fellowships and transition-to-practice years, predominantly. Most programs offer some form of enfolded fellowship. This serves as a basis for characterization of how neurological surgery training may develop in years to come.

Comparison of Perioperative Complications After Anterior-Posterior Versus Posterior-Anterior-Posterior Cervical Fusion: A Retrospective Review of 153 Consecutive Cases.

BACKGROUND: Although published data support the utilization of circumferential fusion to treat select cervical spine pathologies, it is unclear whether the posterior-anterior-posterior (PAP) fusion has increased risks compared with the anterior-posterior fusion. OBJECTIVE: To evaluate the differences in perioperative complications between the 2 circumferential cervical fusion approaches. METHODS: One hundred fifty-three consecutive adult patients who underwent single-staged circumferential cervical fusion for degenerative pathologies from 2010 to 2021 were retrospectively reviewed. Patients were stratified into the anterior-posterior ( n = 116) and PAP ( n = 37) groups. The primary outcomes assessed were major complications, reoperation, and readmission. RESULTS: Although the PAP group was older ( P = .024), predominantly female ( P = .024), with higher baseline neck disability index ( P = .026), cervical sagittal vertical axis ( P = .001), and previous cervical operation rate ( P < .00001), the major complication, reoperation, and readmission rates were not significantly different from the 360° group. Although the PAP group had higher urinary tract infection ( P = .043) and transfusion ( P = .007) rates, higher estimated blood loss ( P = .034), and longer operative times ( P < .00001), these differences were insignificant after the multivariable analysis. Overall, operative time was associated with older age (odds ratio [OR] 17.72, P = .042), atrial fibrillation (OR 158.30, P = .045), previous cervical operation (OR 5.05, P = .051), and lower baseline C1 - 7 lordosis (OR 0.93, P = .007). Higher estimated blood loss was associated with older age (OR 1.13, P = .005), male gender (OR 323.31, P = .047), and higher baseline cervical sagittal vertical axis (OR 9.65, P = .022). CONCLUSION: Despite some differences in preoperative and intraoperative variables, this study suggests both circumferential approaches have comparable reoperation, readmission, and complication profiles, all of which are high.

Comparison of Fusion versus Nonunion After 4-Level and 5-Level Anterior Cervical Diskectomy and Fusion With Anterior Plate Fixation.

BACKGROUND: Nonunion remains a concern in multilevel anterior cervical discectomy and fusion (ACDF), yet there are limited data on nonunion after 4 to 5-level ACDF. In fact, the largest series on 4-level or 5-level ACDF focused specifically on the swallowing outcomes. OBJECTIVE: To assess nonunion after 4 to 5-level ACDF. METHODS: Forty-one patients treated with 4 to 5-level ACDF with minimum of 12-month radiographic follow-up were retrospectively reviewed. Nonunion was found in 25 patients (61%) and 42 levels (25%) and complete fusion in 16 (39%) patients and 126 levels (75%). The 2 groups were further compared. RESULTS: One-level nonunion was by far the most common pattern compared with multilevel nonunion. Nonunion occurred more frequently at the caudal than the cranial or middle segments ( P < .0001). There were significantly more subsidence ( P < .0001) and screw fractures/pullouts ( P < .0001) in the nonunion compared with the fusion group. The symptomatic patients were significantly younger than the asymptomatic patients ( P = .044). The symptomatic levels were significantly more than asymptomatic levels ( P = .048). Equal proportion of patients implanted with allograft and polyetheretherketone had nonunion. However, there were markedly more nonunion than fused levels with allograft and more fused than nonunion levels with polyetheretherketone ( P = .023). The reoperation rate was 24.4% and mostly due to nonunion. There were no reoperations within 90 days of the primary surgery. CONCLUSION: The nonunion rate for 4-level and 5-level ACDF may be higher than previously reported. Symptomatic nonunion remains a major reason for reoperation after multilevel ACDF. Baseline characteristics that negatively affect fusion may be obviated by careful patient selection.

Clinical Outcomes After 4- and 5-Level Anterior Cervical Discectomy and Fusion for Treatment of Symptomatic Multilevel Cervical Spondylosis.

OBJECTIVE: There are limited patient-reported outcome measure (PROM) data on 4-level and 5-level anterior cervical discectomy and fusion (ACDF). The largest series to date solely focused on complications. This retrospective series evaluates PROMs after 4-level and 5-level ACDF. METHODS: Pertinent data from adult patients treated with a 4-level or 5-level ACDF in 2011-2019 were analyzed. PROMs and minimal clinically important differences (MCIDs) were assessed. Factors associated with favorable and unfavorable outcomes were identified. RESULTS: There were 34 patients (30 underwent 4-level and 4 underwent 5-level ACDFs) with a mean age of 59.6 years; 55.9% were women. At 3 months, there were significant improvements in PROMs except Short-Form 12-Item Survey (SF-12) mental component subscale, which showed modest improvement. At 12 months, there were significant improvements in PROMs except SF-12 physical component subscale (PCS), which showed moderate improvement. The proportions of patients who met the MCID cutoffs ranged from 35.3% (numeric rating scale [NRS]-neck) to 75% (Veteran RAND 12-Item Survey [VR-12] PCS) at 3 months and 38.2% (NRS-arm) to 65.5% (VR-12 mental component subscale) at 12 months. Shorter symptom duration was associated with significantly reduced postoperative pain and Neck Disability Index scores. Shorter length of stay was associated with significantly improved postoperative functional outcomes. patients undergoing 4-level compared with 5-level ACDF achieved better postoperative PROMs. Shorter procedure duration was associated with improved PROMs at 3 months. No patient returned to the operating room within 30 days. Patients who required reoperation achieved significantly inferior Neck Disability Index, NRS-neck, and SF-12 PCS scores at 3 months. CONCLUSIONS: This study showed satisfactory PROMs up to 12 months after 4-level and 5-level ACDF despite the complication rate. With thorough preoperative planning and meticulous technique, performing this procedure in carefully selected patients may be associated with acceptable PROMs.

Posterior fusion for fragility type 2 odontoid fractures.

OBJECTIVE: The purpose of this study was to evaluate the outcomes of elderly patients with type 2 odontoid fractures treated with an instrumented posterior fusion. METHODS: Ninety-three consecutive patients older than 65 years of age in whom a type 2 odontoid fracture had been treated with a variety of C1-2 posterior screw fixation techniques were retrospectively reviewed. RESULTS: The average age was 78 years (range 65-95 years). Thirty-seven patients had an additional fracture, 30 of which involved C1. Three patients had cervical spinal cord dysfunction due to their injury. All patients had comorbidities. The average total hospitalization was 9.6 days (range 2-37 days). There were 3 deaths and 19 major complications, the most common of which was pneumonia. No patient suffered a vertebral artery injury. Imaging studies were obtained in 64 patients at least 12 months postsurgery (mean 19 months). Fusion was assessed by dynamic radiographs in all cases and with a CT scan in 80% of the cases. Four of the 64 patients did not achieve fusion (6.25% overall). All patients in whom fusion failed had undergone C1 lateral mass fixation and C2 pars (1/29, 3.4%) or laminar (3/9, 33.3%) fixation. CONCLUSIONS: Instrumented posterior cervical fusions may be performed in elderly patients with acceptable morbidity and mortality. The fusion rate is excellent except when bilateral C2 translaminar screws are used for axis fixation.

A retrospective comparison of radiographic and clinical outcomes in single-level degenerative lumbar disease undergoing anterior versus transforaminal lumbar interbody fusion.

BACKGROUND: Single-level lumbar degenerative disc disease (DDD) remains a significant cause of morbidity in adulthood. Anterior lumbar interbody fusion (ALIF) and Transforaminal lumbar interbody fusion (TLIF) are surgical techniques developed to treat this condition. With limited studies on intermediate term outcomes in a single cohort, we compare radiographic and clinical outcomes in patients undergoing ALIF and TLIF. METHODS: A retrospective chart review was performed on 164 patients (111 TLIF; 53 ALIF) over a 60-month period. X-ray radiographs obtained pre-operatively, prior to discharge, and at one year were utilized for radiographic assessment. Segmental lordosis, lumbar lordosis and HRQOL scores were measured preoperatively and at one-year timepoints. RESULTS: Changes in lumbar lordosis and segmental lordosis were significantly greater after ALIF (4.6° vs. -0.6°, P=0.05; 4.7° vs. -0.7°, P<0.05) at one year (mean time, 366±20 days). At one year or greater, there was a greater reduction in mean VAS-leg score in TLIF patients (3.4 vs. 0.6, P<0.05) and ODI score (16.2 vs. 5.4, P<0.05). Similar outcomes were seen for VAS-back, SF-12 Physical Health, and SRS-30 Function/Activity. SF-12 Mental Health scores were found to be lower in patients undergoing TLIF (-3.5 vs. 2.7, P<0.05). CONCLUSIONS: ALIF demonstrated a superior method of increasing lumbar and segmental lordosis. TLIF was utilized more in patients with higher pre-operative VAS-leg pain scores and therefore, showed a greater magnitude of VAS-leg pain improvement. TLIF also demonstrated a greater improvement in ODI scores despite similar baseline scores, suggesting a possible enhanced functional outcome.

Multilevel Minimally Invasive Lumbar Decompression: Clinical Efficacy and Durability to 2 Years.

BACKGROUND: The clinical efficacy of single-level minimally invasive lumbar decompression and/or microdiscectomy is well established, with improved postoperative functional outcome and pain scores. However, there is a paucity of clinical data supporting the use of minimally invasive (MIS) techniques in a single operation to address pathology at multiple lumbar levels, and this study attempts to address this issue. METHODS: A retrospective review of prospectively collected data from patients with symptomatic lumbar stenosis and/or disc herniations who underwent multilevel minimally invasive decompression or microdiscectomy from November 2014 to February 2018 was conducted at a single academic medical center. Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI), visual analog scale (VAS) for back and leg pain, 12-Item Short Form Health Survey (SF-12) Physical Component Summary Score (PCS) and Mental Component Summary Score (MCS), and Scoliosis Research Society survey (SRS-30), were prospectively collected before surgery and at 3 months, 6 months, 1 year, and 2 years postoperatively. RESULTS: During the study period, 92 patients received multilevel (≥2 level) MIS lumbar decompression and/or discectomy (69 two level, 21 three level, 2 four level). The mean age at surgery was 69.7 years, and 23 (25%) patients were women. Patient-reported outcomes were significantly improved both in the short and long term except for the SF-12 MCS. Average improvement from baseline was (at 3 months and 2 years, respectively): VAS back, -3.9 and -2.8; VAS leg, -3.6 and -2.6; ODI, -13 and -14.6; SF-12 MCS, 2.8 and -0.3; SF-12 PCS, 6.9 and 10.1; and SRS-30, 0.57 and 0.55. Minimal clinically important difference for the study population was reached for every PROM except SF-12 MCS. Surgical complications occurred in 16 patients (17.4%), and 8 patients (8.6%) required postoperative fusions within 2 years. CONCLUSION: The use of MIS techniques to perform lumbar decompression and/or discectomy at multiple levels was found to be both clinically effective and durable. Fusion rates remained low 2 years after the index surgery and were consistent with literature data for open procedures. LEVEL OF EVIDENCE: 2.

The modified frailty index and patient outcomes following transforaminal lumbar interbody fusion surgery for single-level degenerative spine disease.

OBJECTIVE: The modified frailty index (mFI) is a simple tool that measures physiological reserve based on a thorough history and physical examination. Its use has been validated in several surgical specialties, including spinal deformity surgery. Prior research has suggested no significant differences in clinical outcomes between elderly and nonelderly patients undergoing posterior lumbar interbody fusion. The authors sought to investigate the use of the mFI in patients undergoing transforaminal lumbar interbody fusion (TLIF) and the relationship between frailty scores and clinical outcomes. METHODS: A retrospective chart review was conducted on 198 patients who underwent a single-level TLIF over a 60-month period at a single institution. For all patients, an mFI score was computed incorporating a set of 11 clinical factors to assess preexisting comorbidities and functional status. Clinical follow-up and health-related quality-of-life (HRQOL) scores were obtained at baseline and regular intervals of 6 weeks, 6 months, and 1 year following surgery. RESULTS: Patients were grouped according to their level of frailty: no frailty (mFI = 0), mild frailty (mFI = 0.09), moderate frailty (mFI = 0.18), and severe frailty (mFI ≥ 0.27). One-way ANOVA revealed increasing levels of frailty to be associated with an increased rate of complications, from 10.3% to 63.6%. In addition, increasing levels of frailty were associated with longer hospital length of stay (LOS), from 3.1 days to 6.5 days, and lower rates of disposition to home. At the 1-year follow-up, increased levels of frailty were associated with worse HRQOL measures. CONCLUSIONS: Increasing mFI score was associated with higher morbidity, longer inpatient LOS, and a lower probability of discharge to home in patients undergoing single-level TLIF. Consideration of the mFI may help surgeons improve decision-making across the spectrum of patients who are at risk from frailty.

Changes in Segmental and Lumbar Lordosis After Lateral Lumbar Interbody Fusion With Different Lordotic Cage Angulations.

BACKGROUND: Lateral lumbar interbody fusion (LLIF) affords a wide operative corridor to allow for a large interbody cage implantation for segmental reconstruction. There is a paucity of data describing segmental lordosis (SL) achieved with lordotic implants of varying angles. Here we compare changes in SL and lumbar lordosis (LL) after implantation of 6°, 10°, and 12° cages. METHODS: We retrospectively reviewed LLIF cases over a 5.5-year period. We derived SL and LL using the standard cobb angle measurement from a standing lateral radiograph. We analyzed mean changes in SL and LL over time using the linear mixed effect model to estimate these longitudinal changes. RESULTS: The most frequently treated level was L3-4, followed by L4-5. Significant increases in mean SL were found at each follow-up time point for all the cohorts. In an intercohort comparison, the mean changes in SL at immediate postoperative and last follow-up were significantly greater in the 10° cohort than 6° ([7.4° versus 3.1°, P = .004], [6.1° versus 2.3°, P = .025] respectively). The 12° cohort had higher mean change in SL at last follow-up than the 6° cohort (5.9° versus 2.3°, P = .022). There was no difference in mean change in SL between the 10° and 12° cohorts. No difference in overall mean LL over time was found. In terms of mean change in LL, no difference was observed except at immediate and 6-month postoperative in the 10° cohort ([9.6°, P = .001], [8.5, P = .003] respectively). By comparing mean change in LL, no difference existed except between the 10° and 6° immediately after surgery (9.6° versus 0.2°, P = .006). CONCLUSIONS: LLIF cages significantly improve SL at the index level. However, this increase in SL is greater for 10° and 12° cages than the standard 6° cage. Use of 10° cages also resulted in overall improved LL than 6° cages. LEVEL OF EVIDENCE: 3. CLINICAL RELEVANCE: Lateral lumbar interbody fusion.

Enhanced Recovery After Surgery Pathway for Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion Decreases Length of Stay and Opioid Consumption.

BACKGROUND: Opioid requirements in the perioperative period in patients undergoing lumbar spine fusion surgery remain problematic. Although minimally invasive surgery (MIS) techniques have been developed, there still remain substantial challenges to reducing length of hospital stay (LOS) because of postoperative opioid requirements. OBJECTIVE: To study the effect of implementing an enhanced recovery after surgery (ERAS) pathway in patients undergoing a 1-level MIS transforaminal lumbar interbody fusion (MIS TLIF) at our institution. METHODS: We implemented an ERAS pathway in patients undergoing an elective single-level MIS TLIF for degenerative changes at a single institution. Consecutive patients were enrolled over a 20-mo period and compared with a pre-ERAS group prior to the implementation of the ERAS protocol. The primary outcome was LOS. Secondary outcomes included reduction in morphine milligram equivalent units (MME), pain scores, postoperative urinary retention (POUR), and incidence of postoperative delirium. Patients were compared using the chi-square and Welch's 2-sample t-tests. RESULTS: A total of 299 patients were evaluated in this study: 87 in the ERAS group and 212 in the pre-ERAS group. In the ERAS group, there was a significant reduction in LOS (3.13 ± 1.53 vs 3.71 ± 2.07 d, P = .019), total admission MME (252.74 ± 317.38 vs 455.91 ± 498.78 MME, P = .001), and the number of patients with POUR (48.3% vs 65.6%, P = .008). There were no differences in pain scores. CONCLUSION: This is the largest ERAS MIS fusion cohort published to date evaluating a single cohort of patients in a generalizable manner. This ERAS pathway has shown a substantial decrease in LOS and opioid requirements in the immediate perioperative and postoperative period. There is further work to be done to evaluate patients undergoing other complex spine surgical interventions.

Total subaxial reconstruction.

Cervical deformity, particularly kyphosis, is frequently encountered in surgical practice. While many cases are asymptomatic, some patients may have significant pain and disability. We provide a brief review of the pathophysiology of cervical deformity and the technical aspects of deformity correction in the cervical spine. Anterior techniques reviewed here include anterior cervical discectomy and fusion (ACDF), anterior corpectomy and fusion (ACCF) and anterior osteotomy (ATO). Posterior techniques include laminectomy and fusion, posterior column osteotomy (PCO) and pedicle subtraction osteotomy (PSO). This is a fast-evolving field as our understanding of cervical deformity matures and longer-term surgical outcomes are available.

Analysis and Temporal Evolution of Extubation Parameters for Patients Undergoing Single-Stage Circumferential Cervical Spine Surgery.

OBJECTIVE: Airway obstruction after postoperative extubation is a dreaded but uncommon complication in patients undergoing circumferential cervical spine surgery (CCSS). The cuff leak test (CLT) has been utilized to assess air leak around the endotracheal tube which may reflect airway swelling. In this prospective observational study, we analyze the temporal evolution of CLT and perioperative factors that may influence it. METHODS: Twenty patients undergoing single-stage CCSS were managed according to our extubation protocol. Patients were maintained intubated overnight following surgery. They were extubated if a CLT > 200 mL and both intensive care unit (ICU) and Neurosurgery teams agreed that it was safe. Patients extubated in the first postoperative day (8 of 20) comprised the early group, and the remaining patients (12 of 20) the delayed group. Patient and operative data were analyzed as a single group and comparing both groups. RESULTS: The main indication for surgery was cervical deformity. Median number of levels fused was 5 anteriorly (range, 1-6) and 6 (range, 1-13) posteriorly. Patients were kept intubated for an average of 73.6 hours (range, 26-222 hours) and stayed in the ICU for 119.1 hours (range, 36-360 hours). There were 4 failed extubations and 3 patients (15%) required a tracheostomy. Patient profiles between both groups were very similar across most patient variables but differed significantly regarding infraglottic luminal area (p < 0.05). Patients with larger preoperative cuff leak values tended to have a shorter intubation period (p = 0.053). CONCLUSION: This study objectively demonstrates the difficulties in airway management following CCSS and provides useful insight for preoperative planning and counseling. Local anatomic factors influence airway outcome more than operative factors. The study format does not allow for testing of interventions but we suggest that patients with favorable anatomy (larger infraglottic luminal area) may benefit from a less strict airway management protocol.

Expression of degenerative markers in intervertebral discs of young and elderly asymptomatic individuals.

Intervertebral disc (IVD) degeneration is a remodeling process mediated by several growth factors and cytokines. This process has been extensively studied in vitro and with pathologic specimens obtained during surgery for scoliosis or back pain. However, the occurrence and temporal evolution of these molecules during normal aging, particularly in the cervical segment, is not known. Our objective was to study and compare the presence of putative mediators in the IVD of young (<35 years, G1) and elderly (>65 years, G2) presumably asymptomatic individuals. Thirty C4-5 and C5-6 discs and thirty L4-5 and L5-S1 discs per group were collected during the autopsy of individuals whose family members denied a history of neck or back pain. Discs were divided into anterior, central (lumbar only) and posterior sectors for analysis. Immunohistochemistry for TNF-α, IL-1ß, VEGF, NGF-ß, BDNF, TIMP-1, MMP-1, -2 and -3 was performed and reactivity compared between groups and sectors. All of these molecules were detected in every disc sector of both G1 and G2. Most statistical comparisons (25/45, 55.6%) revealed an increase in mediator expression in G2 in relation to G1. Regional differences in the expression of remodeling enzymes were rare; NGF-ß and BDNF had slightly higher expression in the cervical segment of elderly individuals. A senescent profile with elevated VEGF, MMP-2 and MMP-3 was observed across most G2 disc regions and were generally elevated from G1. In conclusion, the mere presence of any of the studied molecules inside the IVD cannot be considered pathologic. Expression of remodeling enzymes and inflammatory mediators is relatively similar across different vertebral segments and disc regions leading to a common degenerated pattern, while neurotrophins have slightly higher expression in cervical discs. These findings support the concept that disc remodeling in different segments follows a similar pathway that can be potentially mediated to avoid structural failure.

Normal aging in human lumbar discs: An ultrastructural comparison.

The normal aging of the extracellular matrix and collagen content of the human lumbar intervertebral disc (IVD) remains relatively unknown despite vast amounts of basic science research, partly because of the use of inadequate surrogates for a truly normal, human IVD. Our objective in this study was to describe and compare the morphology and ultrastructure of lumbar IVDs in 2 groups of young (G1-<35 years) and elderly (G2->65 years). Thirty L4-5 and L5-S1 discs per group were obtained during autopsies of presumably-asymptomatic individuals and analyzed with magnetic resonance imaging (MRI), a morphological grading scale, light microscopy, scanning electron microscopy (SEM) and immunohistochemistry (IHC) for collagen types I, II, III, IV, V, VI, IX and X. As expected, a mild to moderate degree of degeneration was present in G1 discs and significantly more advanced in G2. The extracellular matrix of G2 discs was significantly more compact with an increase of cartilaginous features such as large chondrocyte clusters. Elastic fibers were abundant in G1 specimens and their presence correlated more with age than with degeneration grade, being very rare in G2. SEM demonstrated persistence of basic structural characteristics such as denser lamellae with Sharpey-type insertions into the endplates despite advanced age or degeneration grades. Immunohistochemistry revealed type II collagen to be the most abundant type followed by collagen IV. All collagen types were detected in every disc sector except for type X collagen. Statistical analysis demonstrated a general decrease in collagen expression from G1 to G2 with an annular- and another nuclear-specific pattern. These results suggest modifications of IVD morphology do not differ between the anterior or posterior annulus but are more advanced or happen earlier in the posterior areas of the disc. This study finally describes the process of extracellular matrix modification during disc degeneration in an unselected, general population and demonstrates it is similar to the same process in the cervical spine as published previously.

Surgical considerations in posterior C1-2 instrumentation in the presence of vertebral artery anomalies: case illustration and review of literature.

Vascular anomalies involving the V3 segment of the vertebral artery are common and may complicate posterior atlantoaxial instrumentation. We report a patient with a fenestrated vertebral artery that underwent successful C1-2 instrumentation and fusion. Various vertebral artery anomalies are discussed with a review of pertinent literature.