Effects of thigh extension on the position of the femoral nerve: application to prone lateral transpsoas approaches to the lumbar spine.

Some authors have suggested that thigh extension during the prone lateral transpsoas approach to the lumbar spine provides the theoretical advantage of providing posterior shift of the psoas muscle and plexus and is responsible for its lower rates of nerve injury. We aimed to elucidate the effects of surgical positioning on the femoral nerve within the psoas muscle via a cadaveric study. In the supine position, 10 fresh frozen adult cadavers had a metal wire secured to the pelvic segment of the femoral nerve and then extended proximally along with its L2 contribution. Fluoroscopy was then used to identify the wires on the femoral nerves in a neutral position and with the thigh extended and flexed by 25 and 45°. Additionally, a lateral incision was made in the anterolateral abdominal wall to mimic a lateral transpsoas approach to the lumbar spine, and measurements were made of the amount of movement in the vertical plane of the femoral nerve from neutral to then 25 and 45° of thigh flexion and extension. On fluoroscopy, the femoral nerves moved posteriorly at a mean of 10.1 mm with thigh extension. Femoral nerve movement could not be detected at any degree of this range of flexion of the thigh. Extension of the thigh to about 30° can move the femoral nerve farther away from the dissection plane by approximately one centimeter. This hip extension not only places the femoral nerve in a more advantageous position for lateral lumbar interbody fusion procedures but also helps to promote accentuation of lumbar lordosis.

A comparison of the MOMS trial results to a contemporaneous, single-institution, postnatal closure cohort.

PURPOSE: We evaluate a single-institution cohort of mothers contemporaneous with the Management of Myelomeningocele Study (MOMS) trial to determine the generalizability of MOMS results and compare shunt rates. METHODS: A retrospective chart review identified patients with myelomeningocele born between 2003 and 2009. We applied MOMS eligibility criteria and compared sociodemographic variables between patients at our institution who would have been eligible or ineligible and MOMS participants. Finally, we applied the original MOMS primary outcome and the revised primary outcome to our cohort. RESULTS: Of the 78 patients, 55 (70.5%) were eligible for the MOMS trial. Mean maternal age, race, and marital status were different from both MOMS groups. Comparing our series to MOMS postnatal shows fewer female infants (44.9 vs. 63.8%, p = 0.017) and more thoracic lesions (12.8 vs. 3.8%, p = 0.038). Shunt rates in our cohort (84.6%) were higher than MOMS prenatal and similar to MOMS postnatal (44.0 and 83.7%, respectively). Fewer children met the original primary outcome than the postnatal group (84.6 vs. 97.8%, p = 0.002). There was no significant difference between our cohort and the prenatal group (84.6 vs. 72.5%, p = 0.058). When applying the revised criteria, we find the opposite: a significant difference between local and MOMS prenatal (84.6 vs. 49.5%, p < 0.001) but no difference between the local group and MOMS postnatal (84.6 vs. 87.0%, p = 0.662). CONCLUSIONS: Mothers in our cohort differ from mothers enrolled in MOMS via several sociodemographic factors. Baseline fetal characteristics show a significantly higher functional lesion level in between our cohort and MOMS. Treatment of hydrocephalus in our series tracks almost identically with original MOMS shunt criteria. Revision of the criteria led to greater concordance between meeting criteria and receiving a shunt in MOMS patients, but changes the results in our series.

Ischiopagus and diprosopus in India: two pairs of conjoined twins perceived as incarnations of Hindu deities.

This article briefly reviews two specific types of conjoined twins, ischiopagus and diprosopus, and discusses recent cases of such twins born in India. Some members of the Hindu community worshiped these conjoined twins as incarnations of Hindu deities. In discussing this phenomenon, the authors aim to elucidate certain features of the faith tradition of Hinduism itself. The reception of these conjoined twins as incarnations of Hindu deities can be understood by examining two salient features of Hindu polytheism: the pictorial depiction of Hindu deities with multiple appendages and the concept of an incarnation, or avatar, of a Hindu deity.

Single-Position Prone Transpsoas Lateral Interbody Fusion Including L4L5: Early Postoperative Outcomes.

BACKGROUND: The lateral lumbar interbody fusion (LLIF) was a revolutionary approach devised by Luiz Pimenta that allowed the surgeon to access the lumbar spine through the major psoas muscle. Although the traditional LLIF had enabled enormous advances, the technique has its drawbacks. A new concept to perform the traditional LLIF has been proposed, with the patient being prone to decubitus with slightly extended legs. Our study aims to analyze the early outcomes of patients who had undergone the prone transpsoas (PTP) for degenerative spine pathologies including the L4/5 level. METHODS: This study was multicentric, retrospective, nonrandomized, noncomparative, and observational. Only participants who received PTP in L4/5, with no more than 3 levels of intersomatics and fixation no further than S1, were included. The primary outcomes were the onset of new neurologic deficits and postoperative complications. Also, surgery details, such as blood loss and surgery duration, were measured. Neurologic deficits were accessed at the postoperative visit, which ranged from 7 to 14 days after surgery. RESULTS: Twenty-seven patients fulfilled the inclusion and exclusion criteria, with the majority receiving PTP only in L4/5 (66.6%). The mean surgery time was 182, with 29 minutes of mean transpsoas time. Of the patients, only 1 presented the onset of a motor deficit, while 3 patients presented a new sensory deficit. Five complications occurred, none intraoperative and 5 postoperative, with only 1 directly correlated with the access. CONCLUSIONS: The prone transpsoas is safe and feasible for approaching the L4/5 disk, presenting with a low rate of complication and new-onset neurologic deficits.

Initial multi-centre clinical experience with prone transpsoas lateral interbody fusion: Feasibility, perioperative outcomes, and lessons learned.

BACKGROUND: Lateral interbody fusion (LIF) is traditionally performed with the patient in lateral decubitus, requiring repositioning to prone for adjunctive posterior procedures, or modifying traditional posterior techniques to be done while positioned lateral. The benefits of lateral anterior column access may be achievable with the patient prone, allowing for concomitant posterior techniques in a more familiar single-position setting. METHODS: Prone transpsoas (PTP) access was outlined and vetted by a group of LIF-experienced spine surgeons. Early clinical experience included prospectively capturing procedural details and perioperative outcomes across a multi-centre cohort of clinicians to assess feasibility and to identify efficiencies and/or challenges. RESULTS: Perioperative data was prospectively collected from 120 consecutive cases (176 levels) from 22 surgeons. Lateral exposure was achieved in an average 18 min/level, guided by triggered EMG; and retraction time averaged 25 min/level, with continued plexus monitoring via saphenous SSEP. Fixation was via percutaneous pedicle screws (65%), open pedicle screws (24%), other (11%). No re-positioning was required. Concomitant procedures facilitated by prone position included direct decompression (37%), treatment at L5-S1 (18%), posterior instrumentation revision (7%), and osteotomy/bony releases (9%). PTP procedure time, blood loss, and length of stay were consistent with established LIF experience. Challenges included patient movement with lateral instrument forces, retractor sag, stability of access relative to the patient, and surgeon ergonomics of the working channel. These challenges were overcome later in the experience through development of a specialized positioner and retractor system specific to this approach and a prescribed workflow developed by consensus of the surgeons. CONCLUSION: Initial multi-centre clinical experience suggests that PTP is not only feasible but creates efficiencies by allowing for single-position surgery maximizing both anterior and posterior column access and corrective techniques, with perioperative outcomes consistent with lateral decubitus experience. Learnings included the need for development of procedure-specific technologies and technique refinement.

Seizure outcomes after stereotactic radiosurgery for the treatment of cerebral arteriovenous malformations.

OBJECTIVE Patients with cerebral arteriovenous malformations (AVMs) commonly present with seizure. Seizure outcomes in patients treated with stereotactic radiosurgery (SRS) are poorly defined. A case series of patients with cerebral AVMs treated with SRS is presented to evaluate long-term seizure outcome. METHODS A retrospective review of the medical record was performed, identifying 204 consecutive patients with AVMs treated with SRS between January 1991 and June 2012. Clinical and radiographic data were evaluated. Seizure outcome was measured using the Engel Epilepsy Surgery Outcome Scale. Mean duration of follow-up was 37.1 months (SD 38.3 months) with a minimum follow-up period of 1 month. RESULTS Of the 204 patients with cerebral AVMs treated with SRS, 78 patients (38.2%) presented with seizures and 49 of those patients were treated with antiepileptic drugs (AEDs). Following SRS, 63 (80.8%) of the 78 patients who had had seizures prior to SRS were seizure-free at a mean follow-up time of 37.2 months (SD 41.3 months). Of the 49 patients who had been treated with AEDs, 17 were still taking AEDs at last follow-up. Of the 126 patients who did not present with seizures prior to treatment with SRS, only 5 patients (4.0%) had seizures in the post-SRS period. There was no significant correlation between post-SRS seizure status and patient demographic features, comorbidities, AVM characteristics, history of operative intervention, pre- or posttreatment hemorrhage, or radiographic degree of AVM resolution. CONCLUSIONS Stereotactic radiosurgery for treatment of cerebral AVMs is effective at providing long-term control of seizures. A substantial number of patients who were treated with SRS were not only seizure free at their last follow-up, but had been successfully weaned from antiepileptic medications.

Cryptococcus gattii in an Immunocompetent Patient in the Southeastern United States.

Cryptococcal infections are seen throughout the United States in both immunocompromised and immunocompetent patients. The most common form is C. neoformans. In the Northwestern United States, C. gattii has received considerable attention secondary to increased virulence resulting in significant morbidity and mortality. There are no cases in the extant literature describing a patient with C. gattii requiring neurosurgical intervention in Alabama. A middle-aged immunocompetent male with no recent travel or identifiable exposure presented with meningitis secondary to C. gattii. The patient underwent 12 lumbar punctures and a ventriculoperitoneal shunt and required 83 days of inpatient therapy with 5-flucytosine and amphotericin B. The patient was found to have multiple intracranial lesions and a large intramedullary spinal cryptococcoma within his conus. Following an almost 3-month hospitalization the patient required treatment with oral voriconazole for one year. In the United States meningitis caused by C. gattii infection is not isolated to the Northwestern region.

Deep Brain Stimulation Battery Longevity: Comparison of Monopolar Versus Bipolar Stimulation Modes.

BACKGROUND: Deep brain stimulation is an effective treatment for movement disorders, but it is relatively complex, invasive, and costly. Little is known about whether stimulation mode alters pulse generator (battery) longevity in routine clinical care. OBJECTIVE: To compare battery longevity during monopolar versus bipolar stimulation in patients who underwent deep brain stimulation for movement disorders. METHODS: We evaluated 2,902 programming adjustments and calculated the average stimulator settings for 393 batteries in 200 unique patients with Parkinson's disease and essential tremor. We classified the pulse generators into different stimulation modes (monopolar, bipolar, tripolar, double monopolar) and compared battery longevity with Kaplan Meier survival analyses using the log rank test. We exclusively implanted the Medtronic 3387 lead with adjacent electrode contacts separated by 1.5 mm. RESULTS: The mean pulse generator longevity was 47.6±1.6 months regardless of diagnosis or stimulation mode. Bipolar stimulation mode was associated with greater longevity than monopolar stimulation (56.1±3.4 versus 44.2±2.1 months, p=0.006). This effect was most pronounced when stimulation parameters were at low to moderate intensity settings. Double monopolar configuration was associated with less pulse generator longevity than conventional stimulation modes (37.8±5.6 versus 49.7±1.9, p=0.014). CONCLUSION: IPGs initially programmed in bipolar mode provided one year of additional battery longevity versus monopolar mode in this large retrospective series of patients with essential tremor and Parkinson's disease. Given satisfactory efficacy for motor symptoms, bipolar stimulation mode is a feasible alternative programming strategy at the initiation of DBS therapy.

Adverse events associated with deep brain stimulation for movement disorders: analysis of 510 consecutive cases.

BACKGROUND: Although numerous studies have focused on the efficacy of deep brain stimulation (DBS) for movement disorders, less is known about surgical adverse events, especially over longer time intervals. OBJECTIVE: Here, we analyze adverse events in 510 consecutive cases from a tertiary movement disorders center at up to 10 years postoperatively. METHODS: We conducted a retrospective review of adverse events from craniotomies between January 2003 and March 2013. The adverse events were categorized into 2 broad categories--immediate perioperative and time-dependent postoperative events. RESULTS: Across all targets, perioperative mental status change occurred in 18 (3.5%) cases, and symptomatic intracranial hemorrhage occurred in 4 (0.78%) cases. The most common hardware-related event was skin erosion in 13 (2.5%) cases. The most frequent stimulation-related event was speech disturbance in 16 (3.1%) cases. There were no significant differences among surgical targets with respect to the incidence of these events. Time-dependent postoperative events leading to the revision of a given DBS electrode for any reason occurred in 4.7% ± 1.0%, 9.3% ± 1.4%, and 12.4% ± 1.5% of electrodes at 1, 4, and 7 years postoperatively, respectively. Staged bilateral DBS was associated with approximately twice the risk of repeat surgery for electrode replacement vs unilateral surgery (P = .020). CONCLUSION: These data provide low incidences for adverse events in a large series of DBS surgeries for movement disorders at up to 10 years follow-up. Accurate estimates of adverse events will better inform patients and caregivers about the potential risks and benefits of surgery and provide normative data for process improvement.

The nonsurgical nature of patients with subarachnoid or intraparenchymal hemorrhage associated with mild traumatic brain injury.

OBJECT: Mild traumatic brain injury (mTBI), as defined by Glasgow Coma Scale (GCS) score of 13 or higher, is a common problem in the United States and worldwide, estimated to affect more than 1 million patients yearly. When associated with intracranial hemorrhage, it is a common reason for neurosurgical consultation and transfer to tertiary care centers. The authors set out to investigate the clinical implications of subarachnoid hemorrhage (SAH) and/or intraparenchymal hemorrhage (IPH) associated with mTBI in hopes of standardization of mTBI clinical care and optimization of resource allocation. METHODS: The authors performed a retrospective review of 500 consecutively treated patients with mTBI and SAH and/or IPH admitted to a Level I trauma center in Alabama between May 2003 and May 2013. They performed a review of medical records to confirm the diagnosis, determine neurological condition at admission, and assess for episodes of neurological decline or brain injury-related complications including altered mental status, seizures, and hyponatremia. RESULTS: Of the 500 patients for whom data were reviewed, 304 (60.8%) were male and 196 (39.2%) were female. Average age was 46.3 years. Overall, 63 patients (12.6%) had isolated IPH, 411 (82.2%) had isolated SAH, and 26 (5.2%) had radiographic evidence of both IPH and SAH. One hundred forty-five patients (29%) were transferred an average distance of 64.5 miles. The authors identified no patients who experienced neurological worsening during their hospital course. Two patients experienced hyponatremia that required treatment with sodium supplementation. CONCLUSIONS: Patients with the constellation of SAH and/or IPH and mTBI do not require neurosurgical consultation, and these findings should not be used as the sole criteria to justify transfer to tertiary referral centers.

Validation and modification of a predictive model of postresection hydrocephalus in pediatric patients with posterior fossa tumors.

OBJECT: Postresection hydrocephalus is observed in approximately 30% of pediatric patients with posterior fossa tumors. However, which patients will develop postresection hydrocephalus is not known. The Canadian Preoperative Prediction Rule for Hydrocephalus (CPPRH) was developed in an attempt to identify this subset of patients, allowing for the optimization of their care. The authors sought to validate and critically appraise the CPPRH. METHODS: The authors conducted a retrospective chart review of 99 consecutive pediatric patients who presented between 2002 and 2010 with posterior fossa tumors and who subsequently underwent resection. The data were then analyzed using bivariate and multivariate analyses, and a modified CPPRH (mCPPRH) was applied. RESULTS: Seventy-six patients were evaluated. Four variables were found to be significant in predicting postresection hydrocephalus: age younger than 2 years, moderate/severe hydrocephalus, preoperative tumor diagnosis, and transependymal edema. The mCPPRH produced observed likelihood ratios of 0.737 (95% CI 0.526-1.032) and 4.688 (95% CI 1.421-15.463) for low- and high-risk groups, respectively. CONCLUSIONS: The mCPPRH utilizes readily obtainable and reliable preoperative variables that together stratify children with posterior fossa tumors into high- and low-risk categories for the development of postresection hydrocephalus. This new predictive model will aid patient counseling and tailor the intensity of postoperative clinical and radiographic monitoring for hydrocephalus, as well as provide evidence-based guidance for the use of prophylactic CSF diversion.

Surgical treatment of rathke cleft cysts in children.

OBJECTIVE: Rathke cleft cysts (RCCs) are cystic epithelial lesions in the sellar and suprasellar regions that are often discovered incidentally. They require surgical fenestration and drainage in a small proportion of patients who develop symptoms or demonstrate progressive enlargement. Our aim was to review our experience with pediatric patients treated surgically for RCCs. METHODS: A retrospective review was conducted of all patients treated surgically for RCCs at Childrens Hospital Los Angeles between 1999 and 2007 after approval by the institutional review board. Clinical notes, operative reports, radiological studies, and pathology reports were reviewed. The median follow-up period was 34 months. RESULTS: Ten patients undergoing surgical treatment of an RCC were identified, making up 20% of the 51 patients with RCCs followed clinically over the same time period. The mean age was 13 years (age range, 2-17 years). There were 6 females and 4 males. Patients requiring surgery presented with the following clinical symptoms: headache (8 patients, 80%), endocrine insufficiency (6 patients, 60%), meningitis followed by visual loss (1 patient, 10%), and incidental finding (1 patient, 10%). The mean cyst diameter was 13.6 mm (range, 8-18 mm). Four patients had strictly sellar lesions, 4 patients had suprasellar extension of an RCC, and 2 patients had primarily suprasellar RCCs. Nine of 10 patients underwent transsphenoidal surgery, and 1 patient underwent a pterional craniotomy. Complete cyst drainage on radiography was noted in 9 of 10 patients (90%), all of whom underwent transsphenoidal surgery. One patient experienced a symptomatic recurrence 6 years after complete surgical drainage. Headaches improved in 7 of 8 patients after surgery. Two patients had complete resolution of a hormonal axis deficit, whereas 3 patients developed new anterior pituitary axis deficits. Two patients developed persistent diabetes insipidus after surgery. CONCLUSION: RCCs are an infrequent cause of symptoms in pediatric patients. The transsphenoidal approach offers an effective means of achieving complete cyst drainage for lesions requiring surgery. Fenestration and aspiration of the cyst are usually sufficient to achieve total resolution of symptoms and signs caused by RCCs. Clinical symptoms such as headaches improved in the majority of patients, whereas hormonal disturbances typically persisted. Patient selection remains of paramount importance when considering surgery for pediatric patients with RCCs.