Implications of outgroup selection in the phylogenetic inference of hominoids and fossil hominins.

Understanding the phylogenetic relationships among hominins and other hominoid species is critical to the study of human origins. However, phylogenetic inferences are dependent on both the character data and taxon sampling used. Previous studies of hominin phylogenetics have used Papio and Colobus as outgroups in their analyses; however, these extant monkeys possess many derived traits that may confound the polarities of morphological changes among living apes and hominins. Here, we consider Victoriapithecus and Ekembo as more suitable outgroups. Both Victoriapithecus and Ekembo are anatomically well known and are widely accepted as morphologically primitive stem cercopithecoid and hominoid taxa, respectively, making them more appropriate for inferring polarity for later-occurring hominoid- and hominin-focused analyses. Craniodental characters for both taxa were scored and then added to a previously published matrix of fossil hominin and extant hominoid taxa, replacing outgroups Papio and Colobus over a series of iterative analyses using both parsimony and Bayesian inference methods. Neither the addition nor replacement of outgroup taxa changed tree topology in any analysis. Importantly, however, bootstrap support values and posterior probabilities for nodes supporting their relationships generally increased compared to previous analyses. These increases were the highest at extant hominoid and basal hominin nodes, recovering the molecular ape phylogeny with considerably higher support and strengthening the inferred relationships among basal hominins. Interestingly, however, the inclusion of both extant and fossil outgroups reduced support for the crown hominid node. Our findings suggest that, in addition to improving character polarity estimation, including fossil outgroups generally strengthens confidence in relationships among extant hominoid and basal hominins.

Frontal sinus size in South African Later Stone Age Holocene Khoe-San.

Frontal size variation is comparatively poorly sampled among sub-Saharan African populations. This study assessed frontal sinus size in a sample of Khoe-San skeletal remains from South African Later Stone Age contexts. Volumes were determined from CT scans of 102 adult crania; individual sex could be estimated in 82 cases. Sinus volume is not sexually dimorphic in this sample. The lack of frontal sinus aplasia is concordant with the low incidences recorded for other sub-Saharan African and most other global populations save those that inhabit high latitudes. There is considerable variation in frontal sinus size among global populations, and the Khoe-San possess among the smallest. The Khoe-San have rather diminutive sinuses compared to sub-Saharan Bantu-speaking populations but resemble a northern African (Sudanese) population. Genetic studies indicate the earliest population divergence within Homo sapiens to have been between the Khoe-San and all other living groups, and that this likely occurred in Africa during the span of Marine Isotope Stages 8-6. There is scant information on frontal sinus development among Late Quaternary African fossils that are likely either closely related or attributable to Homo sapiens. Among these, the MIS 3 cranium from Hofmeyr, South Africa, exhibits distinct Khoe-San cranial affinities and despite its large size has a very small frontal sinus. This raises the possibility that the small frontal sinuses of the Holocene South African Khoe-San might be a feature retained from an earlier MIS 3 population.

Sutton's law in epilepsy: because that is where the lesion is.

Successful epilepsy surgery requires unambiguous identification of the epileptogenic zone. This determination may be a challenge when the pre-surgical evaluation yields conflicting data. We evaluated an adult patient with a right insular mass, but a seizure semiology, interictal EEG, and ictal EEG, suggesting left temporal lobe epilepsy. Resection of the mass, a ganglioglioma, resulted in seizure freedom and disappearance of interictal left temporal lobe epileptiform discharges. This case illustrates the principle that in localization-related epilepsy, the money is usually in the mass.

Application-Specific Adaptable Coatings for Sensors: Using a Single Polymer-Plasticizer Pair to Detect Aromatic Hydrocarbons, Mixtures, and Interferents in Water with Single Sensors and Arrays.

A relatively simple design procedure is presented for new, adaptable chemical sensor coatings made from a single polymer-plasticizer pair to detect single or a mixture of chemical compounds (e.g., BTEX, the small aromatic hydrocarbon family). Affinity between coating components and target analytes, expressed through Hansen solubility parameters and relative energy difference values, describes the sensitivity of the resultant coatings to each analyte. While analyte affinity is paramount for plasticizer selection, for the aqueous-phase sensing application described here, it must be traded off with the permanence in the host polymer, i.e., resistance to leaching into the ambient aqueous phase; deleterious effects including coating creep must also be minimized. By varying the polymer:plasticizer mixing ratio, the physical and chemical properties of the resultant coatings can be tuned across a range of sensing properties, in particular the differential response magnitude and rate, for multiple analytes. Together with the measurement of multiple sensor response parameters (relative sensitivity and response time constant) for each coating, this approach allows for identification and quantification of target analytes not previously separable using commercial off-the-shelf (COTS) polymer sensor coatings. Sensing results using a five-sensor array based on five different mixing ratios of a single plasticizer polymer pair (plasticizer: ditridecyl phthalate; polymer: polystyrene) demonstrate unique identification of mixtures of BTEX analytes, including differentiation of the chemical isomers ethylbenzene and total xylene (or "xylenes"), something not previously feasible for separation-free liquid-phase sensing with commercially available polymer coatings. Ultimately, the response of a single optimized sensor coating identified and quantified the components of various mixtures, including identification of likely interferents, using a customized estimation-theory-based multivariate signal-processing technique.

Identification and Quantitation of Aqueous Single- and Multianalyte Solutions of the Isomers Ethylbenzene, m-, p-, and o-Xylene Using a Single Specifically Tailored Sensor Coating and Estimation Theory-Based Signal Processing.

The isomer-specific detection and quantitation of m-, p-, and o-xylene and ethylbenzene, dissolved singly and as mixtures in aqueous solutions at concentrations from 100 to 1200 ppb by volume, is reported for a specifically designed polymer-plasticizer coating on a shear-horizontal surface acoustic wave (SH-SAW) device. The polystyrene-ditridecyl phthalate-blend coating was designed utilizing Hansen solubility parameters and considering the dipole moment and polarizability of the analytical targets and coating components to optimize the affinity of the sensor coating for the four chemical isomers. The two key coating sorption properties, sensitivity and response time constant, are determined by the (slightly different) dipole moments and polarizabilities of the four target analytes: as analyte dipole moment decreases, coating sensitivity increases; as analyte polarizability decreases, coating response time lengthens. Using the measured sensitivities and time constants for the targets, sensor signals were processed with exponentially weighted recursive-least-squares estimation (EW-RLSE) to identify (with near 100% accuracy) and quantify (with ± 5-7% accuracy) the isomers. This impressive performance was achieved by combining the specifically tailored, high-sensitivity coating and an SH-SAW platform (yielding a detection limit of 5 ppb for the analytes) and using the EW-RLS estimator, which estimates unknown parameters accurately even in the presence of measurement noise and for analytes with only minor differences in response. Identification of the xylene isomers is important for applications including environmental monitoring and chemical manufacturing.

Restoration of Global Sagittal Alignment After Surgical Correction of Cervical Hyperlordosis in a Patient with Emery-Dreifuss Muscular Dystrophy: A Case Report.

CASE: We report a rare cervical hyperlordotic deformity in a 19-year-old woman with Emery-Dreifuss muscular dystrophy and concomitant scoliosis. After standard posterolateral instrumentation and fusion of C2-T1 and extensive soft-tissue release, her neck pain improved and unassisted maintenance of cervical alignment and horizontal gaze were preserved through an 8-year follow-up. More importantly, she exhibited reciprocal correction of compensatory global sagittal malalignment, including lumbar lordosis. CONCLUSIONS: This case highlights the importance of full-spine analysis for all patients with spinal deformity to identify and differentiate primary driver(s) of deformity from compensatory mechanisms to individualize treatment toward what truly drives the patient's disability.

Comparing Predictors of Complications After Anterior Cervical Diskectomy and Fusion, Total Disk Arthroplasty, and Combined Anterior Cervical Diskectomy and Fusion-Total Disk Arthroplasty With a Minimum 2-Year Follow-Up.

INTRODUCTION: Outcomes after anterior cervical diskectomy and fusion (ACDF) and cervical total disk arthroplasty (TDA) are satisfactory, but related morbidity and revision surgery rates are notable. This study sought to determine complication variations among ACDF, TDA, and combined ACDF-TDA as well as predictors of postoperative complications. METHODS: Patients undergoing 1- to 2-level ACDF and/or TDA with at least a 2-year follow-up from 2009 to 2011 were identified from the Statewide Planning and Research Cooperative System database. Patient demographics, hospital-related parameters, mortality, and postoperative outcomes were compared, and their predictors were identified using multivariate logistic regression. RESULTS: A total of 16,510 and 449 individuals underwent ACDF and cervical TDA, respectively, and 201 underwent ACDF-TDA. ACDF-TDA patients had the highest rates of cardiac complications and pulmonary embolism (PE) (P ≤ 0.006), whereas TDA patients had higher individual surgical and device/implant/internal fixation complications (P ≤ 0.025). ACDF-TDA patients experienced the lowest rate of revisions. Cervical TDA increased the odds of any surgical complications (OR = 2.5, P = 0.002), overall complications (OR = 1.57, P = 0.034), and revisions (OR = 2.29, P < 0.001). Deyo index predicted any medical/surgical complications (OR = 1.43 and 1.19, respectively). Female sex was associated with increased odds of readmission (OR 1.30, P < 0.001) but was protective against medical complications (OR = 0.81, P = 0.013). DISCUSSION: Combined ACDF-TDA procedures were not associated with increases in 2-year individual or overall complications, readmissions, or revisions. LEVEL OF EVIDENCE: Level 3-Therapeutic study.

Motion analysis in the axial plane after realignment surgery for adolescent idiopathic scoliosis.

BACKGROUND: This study aimed to define changes occurring in axial plane motion after scoliosis surgery in patients with adolescent idiopathic scoliosis (AIS) using gait analysis. Pre- and postoperative axial plane motion was compared to healthy/control subjects. This may potentially improve our understanding of how motion is impacted by deformity and subsequent surgical realignment. METHODS: 15 subjects with AIS underwent pre- and postoperative radiographic and gait analysis, with focus on axial plane motion (clockwise [CW] and counterclockwise [CCW]). Age, weight, and gender-matched controls (n = 13) were identified for gait analysis. Control, preoperative and postoperative groups were compared with paired student's t-tests. RESULTS: Surgical realignment resulted in significantly decreased in upper thoracic, thoracic, thoracolumbar and lumbar Cobb angles pre-to-postoperatively (36.7° vs. 15.2°, 60.1° vs. 25.6°, 47.7° vs. 17.7° and 27.2° vs. 4.8°, respectively) (all p < 0.05), with no significant change in thoracic kyphosis, lumbar lordosis, central sacral vertical line, pelvic incidence, and sagittal vertical axis. However, pelvic tilt significantly increased from 4.9° to 8.1° (p = 0.035). Using gait analysis: preoperative thoracic axial rotation differed (mean CW and CCW rotation was 1.9° and 3.1° [p = 0.01]), whereas mean CW & CCW pelvic rotation remained symmetric (2.0° and 3.0°; p = 0.44). Postoperatively, CCW thoracic rotation range of motion decreased (CW: 0.6° and CCW: 1.4°; p = 0.31). No significant difference in postoperative pelvic rotation occurred (1.1° and 3.4°; p = 0.10). Compared to controls, AIS patients demonstrated no significant difference in total CW & CCW thoracic motion relative to the pelvis both pre- (14.9° and 12.3°, respectively; p = 0.45) and postoperatively (12.9° and 12.3°, respectively; p = 0.82). SIGNIFICANCE: AIS patients demonstrated abnormal gait patterns in the axial plane compared to normal controls. After surgical realignment and de-rotation, marked improvement in axial plane motion was observed, highlighting how motion analysis can afford surgeons three-dimensional perspective into the patient's functional status.

Revascularizing the upper basilar circulation with saphenous vein grafts: operative technique and lessons learned.

BACKGROUND: The purpose of this study was to report our operative technique and lessons learned using saphenous vein conduits to revascularize the rostral basilar circulation (ie, bypass to the posterior cerebral or superior cerebellar arteries). We also review the evolution of this technique for the treatment of vertebrobasilar insufficiency (VBI) and complex posterior fossa aneurysms. METHODS: Data were collected retrospectively for 8 consecutive patients undergoing rostral basilar circulation saphenous vein bypass grafts at our institution between 1989 and 2004 for the treatment of VBI or in conjunction with Hunterian ligation of complex posterior circulation aneurysms. The indications for treatment, pre- and postoperative neurologic status, angiographic results, operative complications, and long-term clinical outcomes were analyzed for each patient. RESULTS: With clinical and angiographic follow-up ranging from 3 months to 15 years, 7 of 8 bypasses remained patent, 3 of 3 aneurysms remained obliterated, and 4 of 5 patients with VBI experienced resolution of their preoperative symptoms. There were no surgery-related deaths, but 2 patients did experience major neurologic morbidity. The outcomes for the 217 total patients reported in the literature were as follows: 135 excellent (62%), 26 good (12%), 30 poor (14%), and 26 dead (12%). CONCLUSIONS: Despite the risk of serious neurologic complications with this procedure, when one considers the natural history of untreated patients, saphenous vein revascularization of the rostral basilar circulation remains an acceptable option. Although surgical technique has varied, patient selection criteria, graft patency, and patient outcomes have been relatively constant over the past 25 years.

Clinical and radiographically/neuroimaging documented outcome in transforaminal lumbar interbody fusion.

OBJECT: Although transforaminal lumbar interbody fusion (TLIF) is an increasingly popular surgical technique, there are a limited number of studies in which investigators have stratified outcome data with respect to surgical indications or documented radiographically proven and clinical results with respect to disc space height (DSH). The authors conducted a study to evaluate the long-term outcomes after TLIF with respect to surgical indication and radiographic/neuroimaging results. METHODS: Thirty-three consecutive TLIF-treated patients underwent follow-up investigation for a mean of 37 months. Isthmic spondylolysis was present in eight patients, recurrent disc herniation in 14, and degenerative disc disease (DDD) in 11. The operative technique involved the placement of interbody structural allograft, pedicle screw instrumentation, and morcellized autograft in the anterior interbody space and the contralateral intertransverse gutter. Surgery was performed at L4-5 in 16 patients, L5-S1 in 14, L3-4 in two, and both L4-5 and L5-S1 in one patient. Preoperative symptoms were back pain (in 91% of cases), leg pain (in 94%), sensory loss (in 67%), and motor deficits (in 30%). Postoperatively, back pain was improved in 67% of the patients, unchanged in 27%, and worsened in 7%. Leg pain improved in 80% of patients, was unchanged in 10%, and worsened in 10%. Outcome, as measured using the Prolo Functional and Economic Scales, improved from a score of 4.9 to 7. In patients with spondylolysis and recurrent disc herniation outcomes were better than in those with DDD only. There was no correlation of outcome with symptom duration, patient age, or level of surgery. In an independent review of pre- and late postoperative radiographs no significant differences in lordosis angles, Cobb angles, or DSHs were found. Fusion occurred in all cases. CONCLUSIONS: The TLIF procedure was associated with good clinical outcomes and a high fusion rate but no change in the DSH. Patients who present with spondylolysis and recurrent herniations experience better outcome than those with degenerative disease alone.

Pedicle Reduction Osteotomy in the Upper Cervical Spine: Technique, Case Report and Review of the Literature.

OBJECTIVE: To present a case report of the correction of a degenerative cervical 45-degree kyphosis centered at C4 with a single stage PSO. SUMMARY OF BACKGROUND DATA: Correction of a fixed cervical kyphosis is a surgical challenge that is frequently managed with a combination of anterior and posterior surgical procedures. An alternative the three stage operation is a single stage pedicle subtraction osteotomy (PSO). A PSO releases the posterior, middle and anterior columns of the spine by resecting the facet joints, pedicles, and a portion of the vertebral body at the apex of a kyphosis through a posterior approach. METHODS: This was a case report of a patient who had degenerative cervical 45 degree kyphosis and was corrected with a single stage pedicle subtraction osteotomy. We did a literature review to provide information on current techniques to treat these patients. RESULTS: With careful resection of the lateral mass and decompression of the vertebral artery by removal of the posterior margin of the foramen transversarium the upper cervical pedicles can be accessed and a PSO can be performed. The vertebral arteries were not obstructed or kinked with posterior reduction of the PSO in this case. CONCLUSIONS: A closing wedge PSO is a useful tool for correcting fixed kyphotic deformities in the upper cervical spine. Further studies are necessary to evaluate the long-term outcomes in these patients.

Large cell neuroendocrine carcinoma of the lung metastatic to the cauda equina.

BACKGROUND CONTEXT: Large cell neuroendocrine carcinoma of the lung is an aggressive tumor with unique histopathological features. It is not known to metastasize to the spine. PURPOSE: To report a metastatic case of this rare tumor to the cauda equina. STUDY DESIGN: Case report. METHODS: Retrospective case review and review of the literature. RESULTS: The authors report a rare case of a large cell neuroendocrine lung metastasis to the lumbar spine, causing right foot drop. Magnetic resonance imaging revealed a heterogeneously enhancing intradural extramedullary mass at L2/L3 level compressing the surrounding nerve roots. During surgery, the identified nerve roots were encased by the tumor, and the dissection was tedious. Postoperatively, the patient reported significantly improved back pain and he had severe foot weakness. The functional outcome was poor because the patient lost entirely his foot function; however, his back pain improved significantly after surgery. CONCLUSIONS: This is the first published study in which the authors described a metastasis of a rather uncommon lung cancer to the cauda equina. When a lesion of the cauda equina presents with a rapid progressive neurological deficit, leptomeningeal metastasis should be in the differential diagnosis.

Transient syringomyelia leading to acute neurological deterioration after repair of a lipomyelomeningocele: case report.

OBJECTIVE: Transient paraplegia in the immediate postoperative period after lipomyelomeningocele repair is uncommon and is not discussed in the literature. We present the unique case of a patient who developed transient paraplegia 48 hours after lipomyelomeningocele repair attributable to the acute development of a thoracic syrinx. CLINICAL PRESENTATION: At birth, the patient was noted to have a large skin-covered mass in the lumbosacral region. On neurological examination, both iliopsoas and quadriceps exhibited 3/5 motor function, and the plantar flexors and dorsiflexors exhibited 1/5 motor function. Urodynamic studies were normal. Magnetic resonance imaging demonstrated the presence of a lipomyelomeningocele associated with tethering of the spinal cord in the lumbosacral region. INTERVENTION: At 5 months of age, the patient underwent repair of the lipomyelomeningocele. After surgery, the patient developed progressive paraplegia along with bowel and bladder dysfunction. Given the concern about a postoperative hematoma resulting in cauda equina syndrome, the patient returned to the operating room for a wound exploration. No compressive lesion such as a hematoma was found at surgery. A postoperative magnetic resonance imaging scan obtained afterward, however, demonstrated the presence of a large thoracic syrinx. CONCLUSION: Syrinx formation can occur as early as 48 hours after lipomyelomeningocele repair, leading to progressive lower extremity weakness and bowel and bladder incontinence. In the immediate postoperative period, an acute syrinx can mimic cauda equina syndrome, and a magnetic resonance imaging scan is necessary to distinguish between these two entities. In this patient, the syrinx was transient and resolved without a shunting procedure.

Minimally invasive atlantoaxial fixation with a polyaxial screw-rod construct: technical case report.

OBJECTIVE AND IMPORTANCE: Posterior C1-C2 fusion with polyaxial screw and rod fixation has become an accepted means of atlanto-axial stabilization. We describe a novel technique for minimally invasive placement of C1 lateral mass screws and C2 pedicle screws for polyaxial screw-rod stabilization. CLINICAL PRESENTATION: The patient presented with a history of chronic neck pain, as well as a 6-month history of weakness and paresthesias involving her left hand. An Os Odontoideum was present on computed tomographic imaging of the cervical spine. Significant instability was noted on flexion-extension imaging, and magnetic resonance imaging demonstrated mild T2 signal change within the spinal cord. TECHNIQUE: Under fluoroscopic guidance, serial dilators were passed through a 2.5 cm paramedian skin incision to allow placement of an expandable tubular retractor. The exposure was centered on the C2 lateral mass. After expansion of the retractor and further subperiosteal dissection, the C1 and C2 lateral masses were visible permitting placement of a polyaxial screw rod construct. This procedure was carried out bilaterally. CONCLUSION: Placement of C1 lateral mass and C2 pedicle screws using minimally invasive techniques is technically feasible.

Unique features of herniated discs at the cervicothoracic junction: clinical presentation, imaging, operative management, and outcome after anterior decompressive operation in 10 patients.

OBJECTIVE: Disc herniations at the C7-T1 level are unusual (4% of all herniated cervical discs) and are often incorrectly diagnosed because of unusual neurological findings and suboptimal imaging studies. Furthermore, the anterior approach may be problematic because the manubrium and slope of the vertebral bodies away from the surgeon obscures the end plates. The recurrent laryngeal nerve and the thoracic duct may be injured by respective right- or left-sided approaches. A posterior approach to this level has, therefore, been advocated, but results of C7-T1 herniations treated anteriorly have not been specifically addressed in the literature. We, therefore, reviewed our experience in the operative management of patients undergoing single level anterior cervical discectomy and fusion at the C7-T1 interspace for the 10 years ending June 2004 with regard to clinical presentation, imaging, problems of operative exposure, and neurological outcome. METHODS: Of 268 patients with single level anterior cervical discectomy and fusions (ACDFs), 10 (3.7%) had C7-T1 disc herniations. We retrospectively reviewed the medical records, operative reports, and imaging studies of these 10 patients. RESULTS: All patients presented with C8 motor deficit without myelopathy. The operation was carried out through an anterior approach with a skin incision 3 cm above the clavicle. Visualization of the C7-T1 disc space was achieved in all without difficulty. Eight of 10 patients are neurologically intact. CONCLUSION: The C7-T1 disc herniates laterally because of the absence of Luschka joints at this level. Central herniation with myelopathy is rare. An anterior approach was easily accomplished in all patients. Recovery of motor function was related to duration and severity of preoperative deficit.

Role of uncal resection in optimizing transsylvian access to the basilar apex: cadaveric investigation and preliminary clinical experience in eight patients.

OBJECTIVE: The pretemporal approach has gained popularity for the treatment of basilar apex aneurysms. However, it requires the sacrifice of anterior temporal bridging veins to allow posterior temporal lobe retraction and, for patients with dominant pretemporal venous drainage, has the attendant risk of venous hypertension, hemorrhagic venous infarction, or seizures postoperatively. Alternatively, we have found that splitting the sylvian fissure, resecting the uncus, and applying posterolateral retraction to the medial temporal lobe provides a similar exposure to the basilar apex while preserving the anterior temporal bridging veins. To evaluate the transsylvian, trans-uncal approach to the basilar apex, we report our initial clinical results using this exposure in eight consecutive patients. A morphometric cadaveric analysis comparing this approach with the pretemporal approach was also performed. METHODS: For the clinical study, all hospital charts and imaging studies were retrospectively reviewed for patients undergoing the transsylvian, trans-uncal approach for the treatment of an upper basilar trunk aneurysm between July 2000 and July 2002. In the anatomic study, six formalin-fixed cadaver specimens were used. Two sequential exposures of the basilar apex were performed on each specimen side. First, the pretemporal exposure was performed with anteroposterior temporal lobe retraction. Next, after the temporal lobe had been allowed to return to normal anatomic position, the retractor was repositioned on the medial aspect of the temporal lobe superficial to the uncus, and a 10 x 10 x 15-mm volume of uncus was removed. Morphometric measurements were performed for each exposure. RESULTS: Four basilar bifurcation and four superior cerebellar segment aneurysms in eight consecutive patients were successfully clip-ligated by use of the transsylvian, trans-uncal approach. All patients had temporal bridging veins that were preserved, as documented by angiography and operative reports. No patient developed a venous infarction or new postoperative seizures, with a mean follow-up of 9.75 months (range, 0.5-28 mo). The cadaveric analysis revealed that in addition to providing a similar exposure of the upper basilar complex, the transsylvian, trans-uncal approach provided additional exposure of the ipsilateral posterior cerebral and superior cerebellar arteries compared with the pretemporal approach. CONCLUSION: When approaching the basilar bifurcation, the transsylvian, trans-uncal approach provides superior exposure of the ipsilateral superior cerebellar and posterior cerebral arteries compared with the pretemporal approach, while preserving the anterior temporal bridging veins. This approach is most valuable in patients with dominant temporal venous drainage or when additional exposure of the ipsilateral posterior cerebral or superior cerebellar arteries is required.

An unusual case of cerebrospinal fluid pseudocyst in a previously augmented breast.

Cerebrospinal fluid (CSF) drainage catheters can cause a myriad of complications, in large part because they may migrate from their normal location to almost anywhere in the body. We present the unique case of a female patient who had previously undergone bilateral breast augmentation who experienced sudden painless swelling of her right breast 6 weeks after placement of a ventriculoperitoneal shunt. Radiologic examination demonstrated ensnarement of the distal aspect of the shunt around her implant, with subsequent formation of a CSF pseudocyst. Management of this patient included replacement of the shunt, drainage of the CSF pseudocyst, and preservation of the implant.