Lateral interbody fusion combined with open posterior surgery for adult spinal deformity

OBJECTIVE Lateral interbody fusion (LIF) with percutaneous screw fixation can treat adult spinal deformity (ASD) in the coronal plane, but sagittal correction is limited. The authors combined LIF with open posterior (OP) surgery using facet osteotomies and a rod-cantilever technique to enhance lumbar lordosis (LL). It is unclear how this hybrid strategy compares to OP surgery alone. The goal of this study was to evaluate the combination of LIF and OP surgery (LIF+OP) for ASD. METHODS All thoracolumbar ASD cases from 2009 to 2014 were reviewed. Patients with < 6 months follow-up, prior fusion, severe sagittal imbalance (sagittal vertical axis > 200 mm or pelvic incidence-LL > 40°), and those undergoing anterior lumbar interbody fusion were excluded. Deformity correction, complications, and outcomes were compared between LIF+OP and OP-only surgery patients. RESULTS LIF+OP (n = 32) and OP-only patients (n = 60) had similar baseline features and posterior fusion levels. On average, 3.8 LIFs were performed. Patients who underwent LIF+OP had less blood loss (1129 vs 1833 ml, p = 0.016) and lower durotomy rates (0% vs 23%, p = 0.002). Patients in the LIF+OP group required less ICU care (0.7 vs 2.8 days, p < 0.001) and inpatient rehabilitation (63% vs 87%, p = 0.015). The incidence of new leg pain, numbness, or weakness was similar between groups (28% vs 22%, p = 0.609). All leg symptoms resolved within 6 months, except in 1 OP-only patient. Follow-up duration was similar (28 vs 25 months, p = 0.462). LIF+OP patients had significantly less pseudarthrosis (6% vs 27%, p = 0.026) and greater improvement in visual analog scale back pain (mean decrease 4.0 vs 1.9, p = 0.046) and Oswestry Disability Index (mean decrease 21 vs 12, p = 0.035) scores. Lumbar coronal correction was greater with LIF+OP surgery (mean [± SD] 22° ± 13° vs 14° ± 13°, p = 0.010). LL restoration was 22° ± 13°, intermediately between OP-only with facet osteotomies (11° ± 7°, p < 0.001) and pedicle subtraction osteotomy (29° ± 10°, p = 0.045). CONCLUSIONS LIF+OP is an effective strategy for ASD of moderate severity. Compared with the authors' OP-only operations, LIF+OP was associated with faster recovery, fewer complications, and greater relief of pain and disability.

Intravenous tissue-type plasminogen activator therapy is an independent risk factor for symptomatic intracerebral hemorrhage after carotid endarterectomy

BACKGROUND

Carotid endarterectomy (CEA) for symptomatic carotid artery stenosis and intravenous tissue-type plasminogen activator (IV-tPA) for acute ischemic stroke are proven therapies; however, the safety of CEA in stroke patients who recently received IV-tPA has not been established.

OBJECTIVE

To evaluate the safety of CEA in stroke patients who recently received IV-tPA.

METHODS

A retrospective review of patients who underwent CEA for symptomatic carotid artery stenosis was performed. The primary end point was postoperative symptomatic intracerebral hemorrhage (sICH). A univariate analysis of potential risk factors for sICH, including IV-tPA therapy, timing of CEA, degree of stenosis, and stroke severity, was performed. Factors with a value of P < .1 on univariate analysis were tested further.

RESULTS

Among 142 patients, 3 suffered sICH after CEA: 2 of 11 patients treated with IV-tPA (18.2%) and 1 of 131 patients not treated with IV-tPA (0.8%). Both IV-tPA patients suffering sICH underwent CEA within 3 days of tPA administration. On univariate analysis, IV-tPA (P = .02), female sex (P = .09), shorter time between ischemic event and CEA (P = .06), and lower mean arterial pressure during the first 48 hours of admission (P = .08) were identified as risk factors for sICH. On multivariate analysis, IV-tPA was the only significant risk factor (P = .002 by stepwise logistic regression; P = .03 by nominal logistic regression).

CONCLUSION

This study indicates that IV-tPA is an independent risk factor for sICH after CEA. This suggests that CEA should be pursued cautiously in patients who recently received IV-tPA. Early surgery may be associated with an increased risk for sICH.

ABBREVIATIONS

CEA, carotid endarterectomyIV-tPA, intravenous recombinant tissue-type plasminogen activatorMAP, mean arterial pressureNASCET, North American Symptomatic Carotid Endarterectomy TrialNIHSS, National Institutes of Health Stroke ScaleNINDS, National Institute of Neurological Disorders and StrokesICH, symptomatic intracerebral hemorrhageTIA, transient ischemic attack.

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing syndrome secondary to an epidermoid tumor in the cerebellopontine angle

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) syndrome is classified under trigeminal autonomic cephalalgias. This rare headache syndrome is infrequently associated with secondary pathologies. In this paper the authors report on a patient with paroxysmal left retroorbital pain with associated autonomic symptoms of ipsilateral conjunctival injection and lacrimation, suggestive of SUNCT syndrome. After failed medical treatment an MRI sequence was obtained in this patient, demonstrating an epidermoid tumor in the left cerebellopontine angle. The patient's symptoms completely resolved after a gross-total resection of the tumor. This case demonstrates the effectiveness of resection as definitive treatment for SUNCT syndrome associated with tumoral compression of the trigeminal nerve. Early MRI studies should be considered in all patients with SUNCT, especially those with atypical signs and symptoms.

Lumbar laminectomy and fusion with routine local application of vancomycin powder: decreased infection rate in instrumented and non-instrumented cases

OBJECTIVE

Wound infections are one of the most common and potentially devastating complications of spinal surgery. Intra-wound application of vancomycin powder has been shown to lower the infection risk following posterior instrumented fusion, but little evidence supports use in other spinal operations. The goal of this study is to assess the efficacy of vancomycin powder for lumbar laminectomy and fusion, both instrumented and non-instrumented.

METHODS

All cases of lumbar laminectomy and posterior fusion (with or without pedicle screw fixation) by a single surgeon were reviewed from 2007 to 2011. Routine application of 1g vancomycin powder was started in August 2009. Baseline characteristics and operative data were compared between untreated patients and those who received vancomycin powder. Rates of wound infection were compared for all fusions, and then separately for instrumented and non-instrumented cases.

RESULTS

253 patients underwent lumbar laminectomy and fusion between 2007 and 2011. Baseline and operative variables were similar between untreated patients (n=97) and those who received vancomycin powder (n=156). Patients were followed for at least one year. The infection rate fell significantly following introduction of vancomycin powder (from 11% to 0%, p=0.000018). Subgroup analysis revealed significant infection reduction for both instrumented cases (from 12% to 0%, p=0.000806) and non-instrumented cases (from 10% to 0%, p=0.0496). No complications attributable to vancomycin powder were identified.

CONCLUSION

Local vancomycin powder appears to lower the risk of wound infection following lumbar laminectomy and fusion, both instrumented and non-instrumented. Further studies are needed to optimize dosing of vancomycin powder, assess long-term safety and efficacy, and evaluate use in other spinal operations.

Clinical outcomes after selective dorsal rhizotomy in an adult population

OBJECT

Selective dorsal rhizotomy (SDR) is a highly effective and well-established surgical tool for correction of lower-extremity spasticity in children with spastic diplegia caused by cerebral palsy (CP). Although the literature demonstrates considerable immediate and long-term functional benefits in children treated with SDR, the effects of SDR on adults with spastic diplegia have not been thoroughly investigated. The purpose of this retrospective study was to examine the objective and subjective clinical outcomes of SDR on an adult population.

METHODS

We reviewed the charts of 21 consecutive adult patients who underwent SDR for treatment of CP-related spastic diplegia between the years of 1989 and 2007. All patients were treated by a single surgeon (T.S.P.) and underwent formal pre- and postoperative physical therapy assessments to examine joint range of motion (ROM), gross motor function measure (GMFM), and muscle tone. The majority of patients (15/21) exhibited preoperative ambulatory independence without an assistive device. Postoperative assessments were performed at 4 months, but most patients (11/21) had longer follow-up periods (mean, 17.6 ± 30.2 months). All patients were assessed with a telephone survey to estimate pre- and postoperative function with the Katz and Lawton Activities of Daily Living (ADL) Scale.

RESULTS

After SDR surgery, patients experienced significant improvements in lower-extremity passive joint ROM (namely, decreases in hamstring and gastrocnemius tightness) as well as in GMFM crawling and kneeling scores. In addition, spasticity in all measured lower-extremity muscle groups was decreased as compared with preoperative levels. On the basis of our patient self-assessments conducted via telephone, each patient demonstrated subjective improvements in ambulatory ability, spasticity, coordination, joint ROM, pain, overall quality of life, and independence. Also, the Lawton total instrumental ADL scale scores were subjectively improved from preoperative levels. We documented no complications, including postoperative sensory deficits, in any of our patients.

CONCLUSIONS

Our experience suggests that SDR can be an effective treatment for CP-related spastic diplegia in ambulatory adults who are unresponsive to medical therapy and should be considered as a therapeutic option in carefully selected patients. Although our study represents the largest series of adult patients with spastic diplegia to date treated with SDR, the data collected will need to be validated in a larger, prospective clinical trial.

Idiopathic bilateral stenosis of the foramina of Monro treated using endoscopic foraminoplasty and septostomy

Hydrocephalus caused by stenosis of the foramen of Monro is rare. The authors describe a 28-year-old female patient with bilateral foraminal stenosis treated using endoscopic septostomy and unilateral foraminal balloon plasty (foraminoplasty). The patient's hydrocephalus and symptoms resolved postoperatively. Endoscopic strategies may be employed as first-line therapy in this condition.

Craniopharyngioma Clinical Status Scale: a standardized metric of preoperative function and posttreatment outcome

OBJECT

Controversy persists concerning the optimal treatment of craniopharyngiomas in children, and no standard outcome metric exists for comparison across treatment modalities, nor is there one that adequately reflects the multisystem dysfunction that may arise.

METHODS

The authors retrospectively analyzed the records of 86 consecutive children who underwent a uniform treatment paradigm of attempted radical resection performed by a single surgeon. Excluding 3 perioperative deaths and 3 patients with inadequate follow-up, 80 children (34 girls and 46 boys; mean age 9.56 years; mean follow-up 9.6 years) composed the study group (53 primary and 27 previously treated/recurrent tumors). Building on existing classification schemes proposed by De Vile for hypothalamic dysfunction and Wen for overall functional outcome, the authors devised a more nuanced classification system (Craniopharyngioma Clinical Status Scale [CCSS]) that assesses outcome across 5 axes, including neurological examination, visual status, pituitary function, hypothalamic dysfunction, and educational/occupational status at last follow-up (there is a 4-tiered grading scale in each domain, with increasing values reflecting greater dysfunction).

RESULTS

There was a significant increase in pituitary dysfunction following treatment-consistent with the high rates of diabetes insipidus and hypopituitarism common to the surgical management of craniopharyngiomas-and less dramatic deterioration in hypothalamic function or cognitive domains. Significant improvement in vision was also demonstrated, with no significant overall change in neurological status. Preoperative CCSS scores predicted postoperative outcome better than clinical characteristics like patient age, sex, tumor size, and the location or presence of hydrocephalus.

CONCLUSIONS

Preoperative CCSS scores predicted outcome with higher accuracy than clinical or imaging characteristics. In lieu of randomized trials, the CCSS may provide a useful outcome assessment tool for comparison across treatment paradigms and surgical approaches. Long-term follow-up is critical to the analysis of outcomes of craniopharyngioma treatment, given the often-delayed sequelae of all therapies and the high recurrence rates of these tumors.

Voyager 2 in the uranian system: imaging science results

Voyager 2 images of the southern hemisphere of Uranus indicate that submicrometersize haze particles and particles of a methane condensation cloud produce faint patterns in the atmosphere. The alignment of the cloud bands is similar to that of bands on Jupiter and Saturn, but the zonal winds are nearly opposite. At mid-latitudes (-70 degrees to -27 degrees ), where winds were measured, the atmosphere rotates faster than the magnetic field; however, the rotation rate of the atmosphere decreases toward the equator, so that the two probably corotate at about -20 degrees . Voyager images confirm the extremely low albedo of the ring particles. High phase angle images reveal on the order of 10(2) new ringlike features of very low optical depth and relatively high dust abundance interspersed within the main rings, as well as a broad, diffuse, low optical depth ring just inside the main rings system. Nine of the newly discovered small satellites (40 to 165 kilometers in diameter) orbit between the rings and Miranda; the tenth is within the ring system. Two of these small objects may gravitationally confine the e ring. Oberon and Umbriel have heavily cratered surfaces resembling the ancient cratered highlands of Earth's moon, although Umbriel is almost completely covered with uniform dark material, which perhaps indicates some ongoing process. Titania and Ariel show crater populations different from those on Oberon and Umbriel; these were probably generated by collisions with debris confined to their orbits. Titania and Ariel also show many extensional fault systems; Ariel shows strong evidence for the presence of extrusive material. About halfof Miranda's surface is relatively bland, old, cratered terrain. The remainder comprises three large regions of younger terrain, each rectangular to ovoid in plan, that display complex sets of parallel and intersecting scarps and ridges as well as numerous outcrops of bright and dark materials, perhaps suggesting some exotic composition.

Improved flux limits for neutrinos with energies above 10(22) eV from observations with the Westerbork Synthesis Radio Telescope

Particle cascades initiated by ultrahigh energy neutrinos in the lunar regolith will emit an electromagnetic pulse with a time duration of the order of nanoseconds through a process known as the Askaryan effect. It has been shown that in an observing window around 150 MHz there is a maximum chance for detecting this radiation with radio telescopes commonly used in astronomy. In 50 h of observation time with the Westerbork Synthesis Radio Telescope array we have set a new limit on the flux of neutrinos, summed over all flavors, with energies in excess of 4x10(22) eV.

CRANIAL DURAL ARTERIOVENOUS FISTULAE

OBJECTIVE

Cranial dural arteriovenous fistulae (dAVF) with cortical venous drainage (CVD) (Borden Types 2 and 3) are reported to carry a 15% annual risk of intracranial hemorrhage (ICH) or nonhemorrhagic neurological deficit (NHND). The purpose of this study was to compare the clinical course of Type 2 and 3 dAVFs that present with ICH or NHND with those that do not.

METHODS

Twenty-eight patients with Type 2 or 3 dAVFs were retrospectively evaluated. CVD was classified as asymptomatic (aCVD) if patients presented incidentally or with pulsatile tinnitus or orbital phenomena. CVD was classified as symptomatic (sCVD) if patients presented with ICH or NHND. Occurrence of new ICH or new or worsening NHND between diagnosis and disconnection of CVD or last follow-up (if not disconnected) was noted. Overall frequency of events was compared using Fisher's exact test. Cumulative, event-free survival was compared using Kaplan-Meier analysis with log-rank testing.

RESULTS

Of 17 patients with aCVD, 1 (5.9%) developed ICH and none experienced NHND or death during the median 31.4-month follow-up period. Of 11 patients with sCVD, 2 (18.2%) developed ICH and 3 (27.3%) experienced new or worsened NHND over the median 9.7-month follow-up period. One of these patients subsequently died. Overall frequency of ICH or NHND was significantly lower in patients with aCVD versus sCVD (P = 0.022). Respective annual event rates were 1.4 versus 19.0%. aCVD patients had significantly higher cumulative event-free survival (P = 0.0016).

CONCLUSION

Cranial dAVFs with aCVD may have a less aggressive clinical course than those with sCVD.

Spontaneous isolated convexity subarachnoid hemorrhage: presentation, radiological findings, differential diagnosis, and clinical course

Object

The clinical characteristics and overall outcome in patients with spontaneous isolated convexity subarachnoid hemorrhage (SAH) are not well described in the literature. The purpose of this study was to examine the mode of presentation, common origins, radiographic findings, and clinical course in a large case series of such patients.

Methods

A retrospective single-center chart review of all patients in whom nontraumatic primary convexity SAH was diagnosed between 2002 and 2007 was performed. Twenty patients were identified and analyzed for presenting symptoms, radiological and laboratory findings, hospital course, and outcome.

Results

There were 15 women and 5 men in our series, and the mean age was 52 years (range 18–86 years). The most common presenting symptom was headache, with 15 patients experiencing it as a chief complaint. Other frequent manifestations included altered mental status (8 patients), focal neurological deficits (7), and seizure (4 patients). An underlying cause of the hemorrhage was identified in 13 cases, whereas the remainder went unresolved. Of the known causes, 5 were due to posterior reversible encephalopathy syndrome, 3 were caused by thrombocytopenia or anticoagulation, and the remainder were isolated cases of lupus vasculitis, drug-induced vasculopathy, postpartum cerebral angiopathy, hypertensive microangiopathy, and Call–Fleming syndrome. All patients with unknown disease origins had favorable outcomes, whereas 8 of 13 patients with an identifiable underlying disorder experienced favorable outcomes.

Conclusions

Spontaneous isolated convexity SAH is rarely caused by aneurysm rupture, has a distinct mode of presentation, and generally carries a more favorable prognosis than that of aneurysmal SAH.

Frequency of spinal arteriovenous malformations in patients with unexplained myelopathy

The authors reviewed charts of 78 myelopathy patients who underwent spinal angiography for possible arteriovenous malformations (AVMs). Twenty-two patients had an AVM. No neurologic complications from angiography were observed. MRI findings of increased T2 signal or flow voids were strongly associated with AVMs. Spinal angiography should be performed in all patients with unexplained myelopathy after neurologic evaluation and an MRI demonstrating increased T2 signal or flow voids.

Outburst of Jupiter's synchrotron radiation after the impact of comet Shoemaker-Levy 9

Jupiter's nonthermal microwave emission, as measured by a global network of 11 radio telescopes, increased dramatically during the Shoemaker-Levy 9 impacts. The increase was wavelength-dependent, varying from approximately 10 percent at 70 to 90 centimeters to approximately 45 percent at 6 and 36 centimeters. The radio spectrum hardened (flattened toward shorter wavelengths) considerably during the week of impacts and continued to harden afterward. After the week of cometary impacts, the flux density began to subside at all wavelengths and was still declining 3 months later. Very Large Array and Australia Telescope images of the brightness distribution showed the enhancement to be localized in longitude and concentrated near the magnetic equator. The evidence therefore suggests that the increase in flux density was caused by a change in the resident particle population, for example, through an energization or spatial redistribution of the emitting particles.

The Impact Cratering Record on Triton

Impact craters on Triton are scarce owing to the relatively recent resurfacing by icy melts. The most heavily cratered surface has a crater density about the same as the lunar maria. The transition diameter from simple to complex craters occurs at a diameter of about 11 kilometers, and the depth-diameter relationship is similar to that of other icy satellites when gravity is taken into account. The crater size-frequency distribution has a differential -3 slope (cumulative -2 slope) and is the same as that for the fresh crater population on Miranda. The most heavily cratered region is on the leading hemisphere in Triton's orbit. Triton may have a leading-trailing asymmetry in its crater population. Based primarily on the similarity of size distributions on Triton and Miranda and the relatively young surface on Triton, the source of Triton's craters is probably comets. The very peculiar size distribution of sharp craters on the "cantaloupe" terrain and other evidence suggests they are volcanic explosion craters.

Voyager 2 at Neptune: Imaging Science Results

Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds of methane ice suspended in an exceptionally clear atmosphere above a lower deck of hydrogen sulfide or ammonia ices. Neptune's atmosphere is dominated by a large anticyclonic storm system that has been named the Great Dark Spot (GDS). About the same size as Earth in extent, the GDS bears both many similarities and some differences to the Great Red Spot of Jupiter. Neptune's zonal wind profile is remarkably similar to that of Uranus. Neptune has three major rings at radii of 42,000, 53,000, and 63,000 kilometers. The outer ring contains three higher density arc-like segments that were apparently responsible for most of the ground-based occultation events observed during the current decade. Like the rings of Uranus, the Neptune rings are composed of very dark material; unlike that of Uranus, the Neptune system is very dusty. Six new regular satellites were found, with dark surfaces and radii ranging from 200 to 25 kilometers. All lie inside the orbit of Triton and the inner four are located within the ring system. Triton is seen to be a differentiated body, with a radius of 1350 kilometers and a density of 2.1 grams per cubic centimeter; it exhibits clear evidence of early episodes of surface melting. A now rigid crust of what is probably water ice is overlain with a brilliant coating of nitrogen frost, slightly darkened and reddened with organic polymer material. Streaks of organic polymer suggest seasonal winds strong enough to move particles of micrometer size or larger, once they become airborne. At least two active plumes were seen, carrying dark material 8 kilometers above the surface before being transported downstream by high level winds. The plumes may be driven by solar heating and the subsequent violent vaporization of subsurface nitrogen.

The Jupiter System Through the Eyes of Voyager 1

The cameras aboard Voyager 1 have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites. On Jupiter itself, atmospheric motions-the interaction of cloud systems-display complex vorticity. On its dark side, lightning and auroras are observed. A ring was discovered surrounding Jupiter. The satellite surfaces display dramatic differences including extensive active volcanismn on Io, complex tectonism on Ganymnede and possibly Europa, and flattened remnants of enormous impact features on Callisto.

Mercury's Surface: Preliminary Description and Interpretation from Mariner 10 Pictures

The surface morphology and optical properties of Mercury resemble those of the moon in remarkable detail and record a very similar sequence of events. Chemical and mineralogical similarity of the outer layers of Mercury and the moon is implied; Mercury is probably a differentiated planet with a large iron-rich core. Differentiation is inferred to have occurred very early. No evidence of atmospheric modification of landforms has been found. Large-scale scarps and ridges unlike lunar or martian features may reflect a unique period of planetary compression near the end of heavy bombardment by small planetesimals.

Mariner 10 Pictures of Mercury: First Results

Mercury has a heavily cratered surface cotntaining basins up to at least 1300 kilometers diameter flooded with mare-like material. Many features are closely similar to those on the moon, but significant structural differences exist. Major chemical differentiation before termination of accretion is implied.

Venus: Atmospheric Motion and Structure from Mariner 10 Pictures

The Mariner 10 television camieras imaged the planet Venus in the visible and near ultraviolet for a period of 8 days at resolutions ranging from 100 meters to 130 kilometers. Tle general pattern of the atmospheric circulation in the upper tropospheric/lower stratospheric region is displayed in the pictures. Atmospheric flow is symmetrical between north and south hemispheres. The equatorial motions are zonal (east-west) at approxiimnately 100 meters per second, consistent with the previously inferred 4-day retrograde rotation. Angular velocity increases with latitude. The subsolar region, and the region downwind from it, show evidence of large-scale convection that persists in spite of the main zonal motion. Dynamical interaction between the zonal motion and the relatively stationary region of convection is evidenced by bowlike waves.