Transabdominal motor evoked potential neuromonitoring of lumbosacral spine surgery.

BACKGROUND CONTEXT: Transcranial Motor Evoked Potentials (TcMEPs) can improve intraoperative detection of femoral plexus and nerve root injury during lumbosacral spine surgery. However, even under ideal conditions, TcMEPs are not completely free of false-positive alerts due to the immobilizing effect of general anesthetics, especially in the proximal musculature. The application of transcutaneous stimulation to activate ventral nerve roots directly at the level of the conus medularis (bypassing the brain and spinal cord) has emerged as a method to potentially monitor the motor component of the femoral plexus and lumbosacral nerves free from the blunting effects of general anesthesia. PURPOSE: To evaluate the reliability and efficacy of transabdominal motor evoked potentials (TaMEPs) compared to TcMEPs during lumbosacral spine procedures. DESIGN: We present the findings of a single-center 12-month retrospective experience of all lumbosacral spine surgeries utilizing multimodality intraoperative neuromonitoring (IONM) consisting of TcMEPs, TaMEPs, somatosensory evoked potentials (SSEPs), electromyography (EMG), and electroencephalography. PATIENT SAMPLE: Two hundred and twenty patients having one, or a combination of lumbosacral spine procedures, including anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), posterior spinal fusion (PSF), and/or transforaminal lumbar interbody fusion (TLIF). OUTCOME MEASURES: Intraoperative neuromonitoring data was correlated to immediate post-operative neurologic examinations and chart review. METHODS: Baseline reliability, false positive rate, true positive rate, false negative rate, area under the curve at baseline and at alerts, and detection of pre-operative deficits of TcMEPs and TaMEPs were compared and analyzed for statistical significance. The relationship between transcutaneous stimulation voltage level and patient BMI was also examined. RESULTS: TaMEPs were significantly more reliable than TcMEPs in all muscles except abductor hallucis. Of the 27 false positive alerts, 24 were TcMEPs alone, and 3 were TaMEPs alone. Of the 19 true positives, none were detected by TcMEPs alone, 3 were detected by TaMEPs alone (TcMEPs were not present), and the remaining 16 true positives involved TaMEPs and TcMEPs. TaMEPs had a significantly larger area under the curve (AUC) at baseline than TcMEPs in all muscles except abductor hallucis. The percent decrease in TcMEP and TaMEP AUC during LLIF alerts was not significantly different. Both TcMEPs and TaMEPs reflected three pre-existing motor deficits. Patient BMI and TaMEP stimulation intensity were found to be moderately positively correlated. CONCLUSIONS: These findings demonstrate the high reliability and predictability of TaMEPs and the potential added value when TaMEPs are incorporated into multimodality IONM during lumbosacral spine surgery.

Lateral Lumbar Interbody Fusion Revisited: Complication Avoidance and Outcomes with the Mini-Open Approach.

OBJECTIVE: To discuss lessons learned from an initial lateral lumbar interbody fusion (LLIF) experience with a focus on evolving surgical technique, complication avoidance, and new motor and sensory outcomes after implementation of a modified surgical approach. METHODS: A retrospective analysis of a prospectively collected series of all patients undergoing LLIF by the senior author (A.D.L.) from January 2010 to January 2018 after implementation of a modified surgical mini-open technique, compared with previously reported institutional results with the originally recommended percutaneous technique. LLIF-specific complications examined included groin/thigh sensory dysfunction, flank bulge/pseudohernia, psoas-pattern weakness, and femoral nerve injury. RESULTS: The incidence (19%, n = 98 patients) of groin/thigh sensory dysfunction in our cohort was significantly lower than that of the historical control (60%, n = 59) (P < 0.0001). The incidence of abdominal flank bulge/pseudohernia (2.0%, n = 98 patients) in our cohort was improved but not significantly lower than that of the historical control (4.2%, n = 118) (P = 0.36). The incidence of psoas-pattern weakness (3.1%, n = 98) in our cohort was significantly lower than that of the historical control (23.7%, n = 59) (P = 0.0001). The incidence of femoral nerve injury (0%, n = 98 patients) in our cohort was improved but was not significantly lower than that of the historical control (1.7%, n = 118) (P = 0.20). CONCLUSIONS: The adoption of an exclusive mini-open muscle-splitting approach with first-look inspection of the lumbosacral plexus nerve elements may improve motor and sensory outcomes in general and the incidence of postoperative groin/thigh sensory dysfunction and psoas-pattern weakness in particular.

Simultaneous lateral interbody fusion and pedicle screws (SLIPS) with CT-guided navigation.

OBJECTIVES: The advent of minimally invasive, percutaneous techniques for the placement of pedicle screws has led to the evolution of a popular treatment paradigm: anterior or lateral interbody fusions followed by posterior percutaneous pedicle screw placement. We present the operative technique for anterior-to-psoas lateral interbody fusion (ATP-LIF) with simultaneous posterior lumbar percutaneous pedicle screw fixation using intraoperative CT-guided navigation. PATIENTS AND METHODS: This technique capitalizes both on the more oblique approach used in the ATP-LIF procedure, as well as the anatomic clarity gleaned from intraoperative CT-guided navigation, to allow for simultaneous placement of pedicle screws in the lateral position without the need for guiding fluoroscopy. RESULTS: The parallel execution of both procedures, in the lateral position, reduces operative time, consolidates a two-stage procedure into one stage, and eliminates the need for prone re-positioning. The use of intraoperative CT-guided navigation reduces the need for fluoroscopy and overall radiation exposure while allowing for pedicle screw placement and the-LIF procedure in truly simultaneous fashion. In this pilot study, a total of 14 pedicle screws were placed with two lateral breaches (14%). CONCLUSION: Simultaneous Lateral Interbody and Pedicle Screws (SLIPS) represents a meaningful evolution of the newly reported single-position lateral interbody fusion with posterior percutaneous pedicle screw fixation.

Cerebrospinal Fluid Leak and Symptomatic Pseudomeningocele After Intradural Spine Surgery.

OBJECTIVE: To describe the incidence of and characterize risk factors for cerebrospinal fluid leak and symptomatic pseudomeningocele (CSFL/SP) after intradural spine surgery. METHODS: A retrospective analysis of a prospectively collected and consecutive series of patients undergoing intradural spine surgery by the senior author (A.D.L.) was conducted over a period of 20 years. RESULTS: Data on 460 surgeries performed on 430 consecutive patients were gathered. The incidence of CSFL/SP formation was 2.8% (n = 13). Of the 13 cases complicated by CSFL/SP, 4 were successfully managed nonoperatively (4/13, 31%); 9 postoperative CSFL/SP required surgical repair (9/13, 69%), making for an overall postoperative surgical repair rate of 1.9% (9/460). Factors significantly related to development of postoperative CSFL/SP on the Fisher exact test were surgery located at the craniocervical junction (risk ratio [RR] 2.7, P = 0.03) and use of any external cerebrospinal fluid drain (any drain: RR 2.5, P = 0.02; lumbar drain specifically: RR 2.6, P = 0.02), the latter finding most likely being attributable to selection bias. No significant difference was observed between primary dural closure and closure incorporating the use of one or more dural repair adjuncts. In addition, the total number of dural repair adjuncts used did not significantly influence the development of postoperative CSFL/SP. CONCLUSIONS: We present the largest series of intradural spine surgeries focusing specifically on the risk factors for and management of CSFL/SP. Although craniocervical junction surgery and use of external cerebrospinal fluid drain were associated with CSFL/SP, type of closure and type/number of dural substitutes were not.

Transcavernous Approach to the Basilar Apex: A Cadaveric Prosection.

The transcavernous approach to the basilar artery, as initially described by Dolenc, is one of the most common and elegant approaches to the region. It affords a generous working and viewing angle, but it can be technically challenging and requires attention to detail at each step. We investigate this approach in this report via a cadaveric prosection with a focus on the value of each of the component steps in improving surgical view and exposure. The transcavernous approach steps are divided into extradural stages: orbitozygomatic osteotomy (a modern adjunct to Dolenc's original description), drilling of the lesser sphenoid wing, and anterior clinoidectomy; and intradural stages: wide splitting of the Sylvian fissure, unroofing of the oculomotor and trochlear nerves, and posterior clinoidectomy. The surgical windows afforded by each step in the approach are illustrated using microscopic images taken during the cadaveric prosection of a donor who happened to harbor a basilar apex aneurysm. An illustrative case and artist illustrations are used to emphasize the relative value of each step of the transcavernous exposure.

Developmental Considerations in Pediatric Skull Base Surgery.

Objectives To review developmental surgical anatomy and technical nuances related to pediatric skull base surgery. Design Retrospective, single-center case series with literature review. Setting MD Anderson Cancer Center. Participants Patients undergoing pediatric skull base surgery. Main Outcome Measures Review developmental anatomy of the pediatric skull base as it relates to technical nuance of various surgical approaches and insight gained from a 25-year institutional experience with this unique patient population. Results Thirty-nine patients meeting these criteria were identified over a 13-year period from 2003 to 2016 and compared to a previously reported earlier cohort from 1992 to 2002. The most common benign pathologies included nerve sheath tumors (11%), juvenile nasopharyngeal angiofibromas (9.5%), and craniopharyngiomas (4.8%). The most common malignancies were chondrosarcoma (11%), chordoma (11%), and rabdomyosarcoma (11%). Varied surgical approaches were utilized and were similar between the two cohorts save for the increased use of endoscopic surgical techniques in the most recent cohort. The most common sites of tumor origin were the infratemporal fossa, sinonasal cavities, clivus, temporal bone, and parasellar region. Gross total resection and postoperative complication rates were similar between the two patient cohorts. Conclusions Pediatric skull base tumors, while rare, often are treated surgically, necessitating an in depth understanding of the anatomy of the developing skull base.

Feasibility and safety of using thoracic and lumbar cortical bone trajectory pedicle screws in spinal constructs in children: technical note.

Thoracic and lumbar cortical bone trajectory pedicle screws have been described in adult spine surgery. They have likewise been described in pediatric CT-based morphometric studies; however, clinical experience in the pediatric age group is limited. The authors here describe the use of cortical bone trajectory pedicle screws in posterior instrumented spinal fusions from the upper thoracic to the lumbar spine in 12 children. This dedicated study represents the initial use of cortical screws in pediatric spine surgery. The authors retrospectively reviewed the demographics and procedural data of patients who had undergone posterior instrumented fusion using thoracic, lumbar, and sacral cortical screws in children for the following indications: spondylolysis and/or spondylolisthesis (5 patients), unstable thoracolumbar spine trauma (3 patients), scoliosis (2 patients), and tumor (2 patients). Twelve pediatric patients, ranging in age from 11 to 18 years (mean 15.4 years), underwent posterior instrumented fusion. Seventy-six cortical bone trajectory pedicle screws were placed. There were 33 thoracic screws and 43 lumbar screws. Patients underwent surgery between April 29, 2015, and February 1, 2016. Seven (70%) of 10 patients with available imaging achieved a solid fusion, as assessed by CT. Mean follow-up time was 16.8 months (range 13-22 months). There were no intraoperative complications directly related to the cortical bone trajectory screws. One patient required hardware revision for caudal instrumentation failure and screw-head fracture at 3 months after surgery. Mean surgical time was 277 minutes (range 120-542 minutes). Nine of the 12 patients received either a 12- or 24-mg dose of recombinant human bone morphogenic protein 2. Average estimated blood loss was 283 ml (range 25-1100 ml). In our preliminary experience, the cortical bone trajectory pedicle screw technique seems to be a reasonable alternative to the traditional trajectory pedicle screw placement in children. Cortical screws seem to offer satisfactory clinical and radiographic outcomes, with a low complication profile.

Fracture of fusion mass following anterior cervical plate removal: Case report.

We present the case of a delayed pseudoarthrosis resulting from a fracture at the site of a radiographically confirmed anterior cervical fusion following plate removal. In this case, an anterior cervical plate was removed to allow for further surgery at a supra-adjacent level. A modicum of literature exists describing delayed fractures following hardware removal in thoracolumbar fusion constructs. The development of a fracture/pseudoarthrosis following hardware removal at the site of a radiographically confirmed anterior cervical fusion has not been previously reported. We describe the clinical presentation and operative management in the case of this rare and unexpected complication.

Children presenting in delayed fashion after minor head trauma with scalp swelling: do they require further workup?

PURPOSE: It is common to evaluate children who have sustained minor head trauma with computed tomography (CT) of the head. Scalp swelling, in particular, has been associated with intracranial injury. A subset of patients, however, present in delayed fashion, often days after the head trauma, as soft tissue edema progresses and their caregiver notices scalp swelling. We explore the value of further workup in this setting. METHODS: We conducted a retrospective review of a prospectively collected cohort of children ≤24 months of age presenting to the Texas Children's Hospital with scalp swelling more than 24 h following a head trauma. Cases were collected over a 2-year study period from June 1, 2014 to May 31, 2016. RESULTS: Seventy-six patients comprising 78 patient encounters were included in our study. The mean age at presentation was 8.8 months (range 3 days-24 months). All patients had noncontrast CT of the head as part of their evaluation by emergency medicine, as well as screening for nonaccidental trauma (NAT) by the Child Protection Team. The most common finding on CT head was a linear/nondisplaced skull fracture (SF) with associated extra-axial hemorrhage (epidural or subdural hematoma), which was found in 31/78 patient encounters (40%). Of all 78 patient encounters, 43 patients (55%) were discharged from the emergency room (ER), 17 patients (22%) were admitted for neurologic monitoring, and 18 patients (23%) were admitted solely to allow further NAT evaluation. Of those patients admitted, none experienced a neurologic decline and all had nonfocal neurologic exams on discharge. No patient returned to the ER in delayed fashion for a neurologic decline. Of all the patient encounters, no patient required surgery. CONCLUSIONS: Pediatric patients ≤24 months of age presenting to the ER in delayed fashion with scalp swelling after minor head trauma-who were otherwise nonfocal on examination-did not require surgical intervention and did not experience any neurologic decline. Further radiographic investigation did not alter neurosurgical management in these patients; however, it should be noted that workup for child abuse and social care may have been influenced by CT findings, suggesting the need for the future development of a clinical decision-making tool to help safely avoid CT imaging in this setting.

Multicenter retrospective evaluation of the validity of the Thoracolumbar Injury Classification and Severity Score system in children.

OBJECTIVE The Thoracolumbar Injury Classification and Severity Score (TLICS) system was developed to streamline injury assessment and guide surgical decision making. To the best of the authors' knowledge, external validation in the pediatric age group has not been undertaken prior to this report. METHODS This study evaluated the use of the TLICS in a large retrospective series of children and adolescents treated at 4 pediatric medical centers (Texas Children's Hospital, Children's Healthcare of Atlanta, Riley Children's Hospital, and Doernbecher Children's Hospital). A total of 147 patients treated for traumatic thoracic or lumbar spine trauma between February 1, 2002, and September 1, 2015, were included in this study. Clinical and radiographic data were evaluated. Injuries were classified using American Spinal Injury Association (ASIA) status, Denis classification, and TLICS. RESULTS A total of 102 patients (69%) were treated conservatively, and 45 patients (31%) were treated surgically. All patients but one in the conservative group were classified as ASIA E. In this group, 86/102 patients (84%) had Denis type compression injuries. The TLICS in the conservative group ranged from 1 to 10 (mean 1.6). Overall, 93% of patients matched TLICS conservative treatment recommendations (score ≤ 3). No patients crossed over to the surgical group in delayed fashion. In the surgical group, 26/45 (58%) were ASIA E, whereas 19/45 (42%) had neurological deficits (ASIA A, B, C, or D). One of 45 (2%) patients was classified with Denis type compression injuries; 25/45 (56%) were classified with Denis type burst injuries; 14/45 (31%) were classified with Denis type seat belt injuries; and 5/45 (11%) were classified with Denis type fracture-dislocation injuries. The TLICS ranged from 2 to 10 (mean 6.4). Eighty-two percent of patients matched TLICS surgical treatment recommendations (score ≥ 5). No patients crossed over to the conservative management group. Eight patients (8/147, 5%) had a calculated TLICS of 4, which meant they were candidates for surgery or conservative therapy by TLICS criteria. Excluding these patients, the degree of agreement between TLICS and surgeon decision was deemed to be very good (κ = 0.878). CONCLUSIONS The TLICS results and recommendations matched treatment in 96% of conservative group cases. In the surgical group, TLICS recommendations matched treatment in 93% of cases. The TLICS recommendations and surgeon decision making displayed very good concordance. The TLICS appears to be effective in the classification of thoracic and lumbar spine injuries and in guiding treatment in the pediatric age group.

Safety of epidural triamcinolone acetonide use during lumbar decompression surgery in pediatric patients: an association with delayed pseudomeningocele formation.

OBJECTIVE The complication profile of epidural triamcinolone acetonide use during lumbar decompression surgery is not known. However, isolated reports of increased risk of delayed CSF leakage with the use of triamcinolone acetonide in adult spinal surgery patients have been published. The purpose of this study was to determine the safety of epidural triamcinolone acetonide use in conjunction with lumbar decompression surgery in pediatric patients. METHODS The medical records of all patients who underwent lumbar decompression surgery with or without discectomy between July 1, 2007, and July 31, 2015, were retrospectively reviewed. RESULTS During the study period, 58 patients underwent 59 spine procedures at Texas Children's Hospital. There were 33 female and 25 male patients. The mean age at surgery was 16.5 years (range 12-24 years). Patients were followed for an average of 38.2 months (range 4-97 months). Triamcinolone acetonide was used in 28 (of 35 total) cases of discectomy; there were no cases of delayed symptomatic CSF leaks (0%) in the minimally invasive and open discectomies. On the other hand, triamcinolone acetonide was used in 14 (of 24 total) cases of multilevel laminectomy, among which there were 10 delayed CSF leaks (71.4%) requiring treatment. The use of triamcinolone acetonide in patients who underwent multilevel laminectomy was significantly associated with an increased risk of delayed CSF leaks or pseudomeningoceles (Fisher's exact test, p < 0.001). CONCLUSIONS There was an unacceptable incidence of delayed postoperative CSF leaks when epidural triamcinolone acetonide was used in patients who underwent multilevel laminectomy.

Utilization of laser interstitial thermotherapy guided by real-time thermal MRI as an alternative to separation surgery in the management of spinal metastasis.

OBJECT: High-grade malignant spinal cord compression is commonly managed with a combination of surgery aimed at removing the epidural tumor, followed by spinal stereotactic radiosurgery (SSRS) aimed at local tumor control. The authors here introduce the use of spinal laser interstitial thermotherapy (SLITT) as an alternative to surgery prior to SSRS. METHODS: Patients with a high degree of epidural malignant compression due to radioresistant tumors were selected for study. Visual analog scale (VAS) scores for pain and quality of life were obtained before and within 30 and 60 days after treatment. A laser probe was percutaneously placed in the epidural space. Real-time thermal MRI was used to monitor tissue damage in the region of interest. All patients received postoperative SSRS. The maximum thickness of the epidural tumor was measured, and the degree of epidural spinal cord compression (ESCC) was scored in pre- and postprocedure MRI. RESULTS: In the 11 patients eligible for study, the mean VAS score for pain decreased from 6.18 in the preoperative period to 4.27 within 30 days and 2.8 within 60 days after the procedure. A similar VAS interrogating the percentage of quality of life demonstrated improvement from 60% preoperatively to 70% within both 30 and 60 days after treatment. Imaging follow-up 2 months after the procedure demonstrated a significant reduction in the mean thickness of the epidural tumor from 8.82 mm (95% CI 7.38-10.25) before treatment to 6.36 mm (95% CI 4.65-8.07) after SLITT and SSRS (p = 0.0001). The median preoperative ESCC Grade 2 was scored as 4, which was significantly higher than the score of 2 for Grade 1b (p = 0.04) on imaging follow-up 2 months after the procedure. CONCLUTIONS: The authors present the first report on an innovative minimally invasive alternative to surgery in the management of spinal metastasis. In their early experience, SLITT has provided local control with low morbidity and improvement in both pain and the quality of life of patients.

Factors affecting survival in 43 consecutive patients after surgery for spinal metastases from thyroid carcinoma.

OBJECT: Spinal metastases account for the majority of bone metastases from thyroid cancer. The objective of the current study was to analyze a series of consecutive patients undergoing spinal surgery for thyroid cancer metastases in order to identify factors that influence overall survival. METHODS: The authors retrospectively reviewed the records of all patients who underwent surgery for spinal metastases from thyroid cancer between 1993 and 2010 at the University of Texas MD Anderson Cancer Center. RESULTS: Forty-three patients met the study criteria. Median overall survival was 15.4 months (95% CI 2.8-27.9 months) based on the Kaplan-Meier method. The median follow-up duration for the 4 patients who were alive at the end of the study was 39.4 months (range 1.7-62.6 months). On the multivariate Cox analysis, progressive systemic disease at spine surgery and postoperative complications were associated with worse overall survival (HR 8.98 [95% CI 3.46-23.30], p < 0.001; and HR 2.86 [95% CI 1.30-6.31], p = 0.009, respectively). Additionally, preoperative neurological deficit was significantly associated with worse overall survival on the multivariate analysis (HR 3.01 [95% CI 1.34-6.79], p = 0.008). Conversely, preoperative embolization was significantly associated with improved overall survival on the multivariate analysis (HR 0.43 [95% CI 0.20-0.94], p = 0.04). Preoperative embolization and longer posterior construct length were significantly associated with fewer and greater complications, respectively, on the univariate analysis (OR 0.24 [95% CI 0.06-0.93] p = 0.04; and OR 1.24 [95% CI 1.02-1.52], p = 0.03), but not the multivariate analysis. CONCLUSIONS: Progressive systemic disease, postoperative complications, and preoperative neurological deficits were significantly associated with worse overall survival, while preoperative spinal embolization was associated with improved overall survival. These factors should be taken into consideration when considering such patients for surgery. Preoperative embolization and posterior construct length significantly influenced the incidence of postoperative complications only on the univariate analysis.

Prognostic Factors Influencing the Outcome of 64 Consecutive Patients Undergoing Surgery for Metastatic Melanoma of the Spine.

BACKGROUND: Melanoma metastases to the spine remain a challenge for neurosurgeons. OBJECTIVE: To identify factors associated with survival in a series of patients who underwent spinal surgery for metastatic melanoma. METHODS: We retrospectively reviewed all patients (n = 64) who received surgical intervention for melanoma metastases to the spine at the University of Texas MD Anderson Cancer Center between July 1993 and March 2012. RESULTS: No patients were excluded from the study, and vital status data were available for all patients. Median overall survival was 5.7 months (95% confidence interval, 2.7-28.7). On univariate survival analysis, diagnosis of spinal metastasis after prior diagnosis of systemic metastasis, higher total spinal disease burden (including but not exclusive to the operative site), presence of progressive systemic disease at the moment of spine surgery, and postoperative complications were associated with poorer overall survival, whereas the presence of only bone metastasis at the moment of surgery was associated with improved overall survival. On multivariate survival analysis, both progressive systemic disease at the moment of spine surgery and total spinal disease burden of ≥3 vertebral levels were significantly associated with worse overall survival (hazard ratio, 6.00; 95% confidence interval, 3.19-11.28; P < .001; and hazard ratio, 2.87; 95% confidence interval, 1.62-5.07; P < .001, respectively). CONCLUSION: On multivariate analysis, involvement of ≥3 vertebral bodies and progressive systemic disease were associated with worse overall survival. Consideration of these factors should influence surgical decision making in this patient population.

Factors affecting survival in 37 consecutive patients undergoing de novo stereotactic radiosurgery for contiguous sites of vertebral body metastasis from renal cell carcinoma.

OBJECT: Palliative resection of renal cell carcinoma (RCC) spinal metastasis is indicated in cases of neurological compromise or mechanical instability, whereas conventional external beam radiotherapy (EBRT) is commonly used for pain control. Recently, spinal stereotactic radiosurgery (SRS) has emerged as a safe alternative, delivering higher therapeutic doses of radiation to spinal metastases. To better understand factors affecting survival in patients undergoing spinal SRS for metastatic RCC, the authors performed a retrospective analysis of a consecutive series of cases at a tertiary cancer center. METHODS: Patients harboring contiguous sites of vertebral body involvement from metastatic RCC who received upfront spinal SRS treatment at The University of Texas MD Anderson Cancer Center between 2005 and 2012 were identified. Demographic data, pain scores, radiographic data, overall survival, complications, status of systemic disease, neurological and functional status, and time between primary diagnosis and diagnosis of metastasis (systemic and spinal) were analyzed to determine their influence on survival. RESULTS: Thirty-seven patients receiving treatment for 40 distinct, contiguous sites of disease were included. The median overall survival after spinal SRS was 16.3 months (range 7.4-25.3 months). Univariate analysis revealed several factors significantly associated with improved overall survival. Local progression after spinal SRS was associated with worse overall survival compared with sustained local control (HR 3.4, 95% CI 1.6-7.4, p = 0.002). Median survival in patients with a Karnofsky Performance Scale (KPS) score ≥ 70 was longer than in patients with a KPS score < 70 (HR 4.7, 95% CI 2.1-10.7, p < 0.001). Patients with neurological deficits at the time of spinal SRS had a shorter median survival than those without (HR 4.2, 95% CI 1.4-12.0, p = 0.008). Individuals with nonprogressive systemic disease at the time of spinal SRS had a longer median survival than those with systemic progression at the time of treatment (HR 8.3, 95% CI 3.3-20.7, p < 0.001). Median survival in patients experiencing any metastasis < 12 months after primary RCC diagnosis was shorter than in patients experiencing any metastasis > 12 months after primary diagnosis, a difference that approached but did not attain significance (HR 1.9, 95% CI 0.90-4.1, p = 0.09). On multivariate analysis, local progression of disease after spinal SRS, metastasis < 12 months after primary, KPS score ≤ 70, and progression of systemic disease at time of spinal SRS all remained significant factors influencing survival (respectively, HR 3.7, p = 0.002; HR 2.6, p = 0.026; HR 4.0, p = 0.002; and HR 13.2, p < 0.001). CONCLUSIONS: We identified several factors associated with survival after spinal SRS for RCC metastases, including local progression, time between first metastasis and primary RCC diagnosis, KPS score, presence of neurological deficits, and progressive metastatic disease. These factors should be taken into consideration when considering a patient for spinal SRS for RCC metastases.

Microvascular decompression of a C-2 segmental-type vertebral artery producing trigeminal hypesthesia.

The authors report a case of trigeminal hypesthesia caused by compression of the spinal cord by a C-2 segmental-type vertebral artery (VA) that was successfully treated with microvascular decompression. Aberrant intradural VA loops have been reported as causes of cervical myelopathy, some of which improved with microvascular decompression. A 52-year-old man presented with progressive complaints of headache, dizziness, left facial numbness, and left upper-extremity paresthesia that worsened when turning his head to the right. Magnetic resonance imaging of the cervical spine showed the left VA passing intradurally between the axis and atlas, foregoing the C-1 foramen transversarium, and impinging on the spinal cord. The patient underwent left C-1 and C-2 hemilaminectomies followed by microvascular decompression of an aberrant VA loop compressing the spinal cord. The patient subsequently reported complete resolution of symptoms.

Utility of computed tomography or magnetic resonance imaging evaluation of ventricular morphology in suspected cerebrospinal fluid shunt malfunction.

OBJECT: It is common to evaluate children with suspected CSF shunt malfunctions using CT of the head or, more recently, "quick brain" MRI. However, the reliability of using ventricular behavior, as assessed on cranial imaging during previous presentations with shunt obstructions, is not well defined. The authors conducted a study to determine if CT or MRI of ventricular morphology added useful clinical information in the evaluation of shunt malfunctions. METHODS: A retrospective chart review of children operated on at Texas Children's Hospital from February 20, 2011, to June 18, 2013, for shunt obstruction was conducted. Inclusion criteria involved age 3 years or older in patients who had undergone two or more shunt revisions for intraoperatively confirmed obstructions. Patients with shunt infection but without shunt obstruction and patients with fourth ventricular shunt failure were excluded from the study. Preoperative CT or MRI results were dichotomized into two distinct categories, as determined by a radiologist's report: either dilation of the ventricular system in comparison with prior scans at points the shunt was deemed functional, or no dilation of the ventricular system in comparison such scans. Determination of the presence of shunt obstruction was assessed by findings documented by the surgeon in the operative report. Each case was then analyzed to see if the patient has a reliable pattern of ventricular dilation, or no dilation, at times of shunt obstruction. RESULTS: Forty-two patients (25 males and 17 females) were included in the study. There were a total of 117 patient encounters analyzed and an average of 2.79 encounters per patient. The mean age at shunt failure presentation was 10.8 years (range 3-23 years). In 4 encounters, patients presented with a CSF leak or pseudomeningocele. Twenty-seven patients (64%) consistently demonstrated dilation of the ventricular system during episodes of shunt obstruction. Four patients (10%) consistently demonstrated no dilation during episodes of shunt obstruction. Eleven patients (26%) demonstrated inconsistent changes in ventricular size at times of shunt obstruction. In those first patient encounters with shunt obstruction presenting with ventricular dilation, 92% (49 of 53) of subsequent encounters demonstrated ventricular dilation with shunt obstruction presentations. CONCLUSIONS: Historical CT or MRI data regarding ventricular morphology patterns seen during prior examinations of shunt obstructions may inform a clinician's judgment of shunt obstruction on subsequent presentations, but they are not conclusive. In the present series, the authors found that changes in the morphology of a given patient's ventricular system when shunt obstruction occurs were often consistent and predictable, but not always. It remains imperative, however, that cranial images obtained to rule out shunt malfunction be compared with prior studies.

Clinical outcomes of the surgical treatment of isolated unilateral facet fractures, subluxations, and dislocations in the pediatric cervical spine: report of eight cases and review of the literature.

PURPOSE: We present a small series consisting of eight children with unilateral facet injury of the cervical spine treated surgically. METHODS: A retrospective review was performed. Injury data, radiographs, surgical data, and outcomes (Neck Disability Index (NDI), Short Form 36 (SF-36), and Visual Analog Scale for Neck Pain (VAS-NP)) were collected from seven patients. A literature review was performed for one additional case. RESULTS: Motor vehicle accidents (62 %, n = 5) and falls (38 %, n = 3) accounted for all injuries. The C6-7 level accounted for most of the injuries (37.5 %, n = 3). The mean NDI score with at least 3 months follow-up was 5.3 (n = 6, range, 1-12; standard deviation, 4.5), corresponding to mild disability. Of the norm-based SF-36 scale scores available (n = 6), the mean physical functioning (PF), role-physical (RP), and role-emotional (RE) scores were significantly less than the adult, age 18-24, norm-based means, with a mean difference of -6.4, -9.13, and -11.3, respectively (p value = 0.03, 0.001, and 0.01, respectively). The mean general health (GH) and vitality (VT) scores, however, were significantly greater than the adult, age 18-24, norm-based mean, with a mean difference of 7.82 and 10.3 (p = 0.04 and 0.02, respectively). VAS-NP showed a return to the "no pain" level at 3 months or more follow-up in all patients. CONCLUSIONS: We suggest that surgical treatment of these injuries in the pediatric age group may lead to satisfactory clinical and radiographic outcomes, but HRQoL analysis suggests that patients remain physically and emotionally disabled to some degree after surgery.