Meningomyelocele Reconstruction: Comparison of Repair Methods via Systematic Review

PURPOSE

The purpose of this article was to appraise the various methods of reconstruction for meningomyelocele (MMC) defects.

METHODS

A systematic review of the literature was performed to evaluate all reconstructions for MMC. The method of reconstruction was categorized by: primary closure with and without fascial flaps, random pattern flaps, VY advancement flaps (VY), perforator flaps, and myocutaneous flaps. Perforator flaps were subsequently subcategorized based on the type of flap.

RESULTS

Upon systematic review, 567 articles were screened with 104 articles assessed for eligibility. Twenty-nine articles were further reviewed and included for qualitative synthesis. Two hundred seventy patients underwent MMC repair. The lowest rates of major wound complications (MWC) were associated with myocutaneous and random pattern flaps. A majority of MWC was in the lumbrosacral/sacral region (87.5% of MWC). In this region, random patterns and perforator flaps demonstrated the lowest rate of MWC (4.5, 8.1%).

CONCLUSIONS

Plastic surgery consultation should be strongly considered for MMC with defects in the lumbosacral/sacral region. Perforator flaps are excellent options for the reconstruction of these defects.

Preoperative Frontal and Parietal Bone Thickness Assessment to Predict Blood Loss and Transfusion During Extended Suturectomy for Isolated Sagittal Craniosynostosis

OBJECTIVE

To predict the morbidity of sagittal suturectomy using preoperative computer tomographic measurement of frontal and parietal bone thickness in osteotomy sites.

DESIGN

Retrospective analysis.

SETTING

Tertiary children's hospital.

PATIENTS

Fifty infants with nonsyndromic, isolated sagittal craniosynostosis who underwent extended sagittal suturectomy from 2015-2022.

METHODS

Mean thickness of the frontal and parietal bone in regions of osteotomies were determined for each patient from preoperative CT images obtained within 30 days prior to suturectomy. The relationship between bone thickness (mm) and estimated blood loss (mL) was evaluated using Spearman's correlation and a multivariable model that adjusted for patient weight and surgery duration. The association between bone thickness and perioperative blood transfusion was evaluated using a multivariable logistic model controlling for patient weight and surgery duration.

MAIN OUTCOME MEASURES

Estimated blood loss, perioperative blood transfusion.

RESULTS

Frontal and parietal bone thickness in the region of osteotomies were positively correlated with estimated blood loss (p < 0.01). After adjusting for patient weight and duration of operation, both parietal and frontal bone thickness were associated with intraoperative blood loss (R2 = 0.292, p = 0.002 and R2 = 0.216, p = 0.026). Thicker frontal and parietal bone in the line of osteotomies resulted in significantly higher odds of blood transfusion. Bone thickness in the line of parietal osteotomies was 76% accurate at identifying patients who would require blood transfusion (p = 0.004).

CONCLUSIONS

Frontal and parietal bone thickness in the line of osteotomies is associated with blood loss and perioperative blood transfusion for sagittal suturectomy operations.

Long term outcome after surgical treatment for hypothalamic hamartoma

PURPOSE

To determine long-term outcome for seizure control and clinical predictors for seizure freedom in patients undergoing surgical treatment for epilepsy associated with hypothalamic hamartoma (HH).

METHODS

155 patients underwent surgical treatment for HHs and treatment-resistant epilepsy at one center (Barrow Neurological Institute at St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA) between February 2003 and June 2010. Data collection included medical record review and direct follow-up interviews to determine seizure outcome. Statistical analysis included descriptive summaries of patient characteristics and time-to-event analysis for seizure freedom.

RESULTS

Long-term survival with follow-up of at least five years since first surgical treatment was available for 108 patients (69.7% of the treatment cohort). The surgical approach for first HH intervention consisted of transventricular endoscopic resection (n = 57; 52.8%), transcallosal interforniceal resection (n = 35; 32.4%), pterional resection (n = 7; 6.5%), and gamma knife radiosurgery (n = 9; 8.3%). Multiple surgical procedures were required for 39 patients (36.1%). There were 10 known deaths from all causes in the treatment cohort (6.5%). Of these, one (0.6%) was related to immediate complications of HH surgery, three (1.9%) were attributed to Sudden Unexpected Death in Epileptic Persons (SUDEP), and one (0.6%) to complications of status epilepticus. For surviving patients with long-term follow-up, 55 (50.9%) were seizure-free for all seizure types. Univariable analysis showed that seizure-freedom was related to 1) absence of a pre-operative history for central precocious puberty (p = 0.01), and 2) higher percentage of HH lesion disconnection after surgery (p = 0.047). Kaplan-Meier survival analysis shows that long-term seizure outcome following HH surgery is comparable to short-term results.

SUMMARY

These uncontrolled observational results show that long-term seizure control following HH surgical treatment is comparable to other forms of epilepsy surgery. Late relapse (at least one year after surgery) and SUDEP do occur, but in a relatively small number of treated patients. These results inform clinical practice and serve as a comparable benchmark for newer technologies for HH surgery, such as magnetic resonance imaging-guided laser interstitial thermal therapy, where long-term outcome results are not yet available.

Hydrocephalus surveillance following CSF diversion: a modified Delphi study

OBJECTIVE

Long-term follow-up is often recommended for patients with hydrocephalus, but the frequency of clinical follow-up, timing and modality of imaging, and duration of surveillance have not been clearly defined. Here, the authors used the modified Delphi method to identify areas of consensus regarding the modality, frequency, and duration of hydrocephalus surveillance following surgical treatment.

METHODS

Pediatric neurosurgeons serving as institutional liaisons to the Hydrocephalus Clinical Research Network (HCRN), or its implementation/quality improvement arm (HCRNq), were invited to participate in this modified Delphi study. Thirty-seven consensus statements were generated and distributed via an anonymous electronic survey, with responses structured as a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). A subsequent, virtual meeting offered the opportunity for open discussion and modification of the statements in an effort to reach consensus (defined as ≥ 80% agreement or disagreement).

RESULTS

Nineteen pediatric neurosurgeons participated in the first round, after which 15 statements reached consensus. During the second round, 14 participants met virtually for review and discussion. Some statements were modified and 2 statements were combined, resulting in a total of 36 statements. At the conclusion of the session, consensus was achieved for 17 statements regarding the following: 1) the role of standardization; 2) preferred imaging modalities; 3) postoperative follow-up after shunt surgery (subdivided into immediate postoperative imaging, delayed postoperative imaging, routine clinical surveillance, and routine radiological surveillance); and 4) postoperative follow-up after an endoscopic third ventriculostomy. Consensus could not be achieved for 19 statements.

CONCLUSIONS

Using the modified Delphi method, 17 consensus statements were developed with respect to both clinical and radiological follow-up after a shunt or endoscopic third ventriculostomy. The frequency, modality, and duration of surveillance were addressed, highlighting areas in which no clear data exist to guide clinical practice. Although further studies are needed to evaluate the clinical utility and cost-effectiveness of hydrocephalus surveillance, the current study provides a framework to guide future efforts to develop standardized clinical protocols for the postoperative surveillance of patients with hydrocephalus. Ultimately, the standardization of hydrocephalus surveillance has the potential to improve patient care as well as optimize the use of healthcare resources.

Hydrogel Check-Valves for the Treatment of Hydrocephalic Fluid Retention with Wireless Fully-Passive Sensor for the Intracranial Pressure Measurement

Hydrocephalus (HCP) is a neurological disease resulting from the disruption of the cerebrospinal fluid (CSF) drainage mechanism in the brain. Reliable draining of CSF is necessary to treat hydrocephalus. The current standard of care is an implantable shunt system. However, shunts have a high failure rate caused by mechanical malfunctions, obstructions, infection, blockage, breakage, and over or under drainage. Such shunt failures can be difficult to diagnose due to nonspecific systems and the lack of long-term implantable pressure sensors. Herein, we present the evaluation of a fully realized and passive implantable valve made of hydrogel to restore CSF draining operations within the cranium. The valves are designed to achieve a non-zero cracking pressure and no reverse flow leakage by using hydrogel swelling. The valves were evaluated in a realistic fluidic environment with ex vivo CSF and brain tissue. They display a successful operation across a range of conditions, with negligible reverse flow leakage. Additionally, a novel wireless pressure sensor was incorporated alongside the valve for in situ intracranial pressure measurement. The wireless pressure sensor successfully replicated standard measurements. Those evaluations show the reproducibility of the valve and sensor functions and support the system’s potential as a chronic implant to replace standard shunt systems.

Pediatric intracranial arterial injuries by penetrating gunshot wounds: an institutional experience

PURPOSE

Pediatric intracranial injuries due to penetrating gunshot wounds are a rare entity that is often fatal. A subset of patients may experience an intracerebral arterial injury; however, literature on the pediatric population is limited. This study analyzes a large institution's experience with pediatric head gunshot wounds and intracranial arterial injuries.

METHODS

All pediatric patients ≤ 18 years of age who presented to our institution with a penetrating gunshot wound from 2008 to 2018 were retrospectively analyzed.

RESULTS

Thirty-seven patients presented with an intracerebral penetrating gunshot injury. There were 18 deaths (49%) in the cohort. A total of 20 patients (54%) had vascular imaging. Of the remaining 17 patients with no vascular imaging, 13 (35%) died before any vascular studies were obtained. Four (20%) of the 20 patients with vascular imaging experienced an intracerebral arterial injury. Three of these 4 patients died before treatment could be administered. One patient with a firearm injury underwent embolization of a distal middle cerebral artery pseudoaneurysm and was discharged home with a Glasgow Outcome Scale score of 5 on follow-up.

CONCLUSION

Pediatric patients with penetrating intracranial gunshot wounds often die before vascular imaging can be obtained.

Three-Dimensionally Printed Microelectromechanical-System Hydrogel Valve for Communicating Hydrocephalus

Hydrocephalus (HCP) is a chronic neurological brain disorder caused by a malfunction of the cerebrospinal fluid (CSF) drainage mechanism in the brain. The current standard method to treat HCP is a shunt system. Unfortunately, the shunt system suffers from complications including mechanical malfunctions, obstructions, infections, blockage, breakage, overdrainage, and/or underdrainage. Some of these complications may be attributed to the shunts' physically large and lengthy course making them susceptible to external forces, siphoning effects, and risks of infection. Additionally, intracranial catheters artificially traverse the brain and drain the ventricle rather than the subarachnoid space. We report a 3D-printed microelectromechanical system-based implantable valve to improve HCP treatment. This device provides an alternative approach targeting restoration of near-natural CSF dynamics by artificial arachnoid granulations (AGs), natural components for CSF drainage in the brain. The valve, made of hydrogel, aims to regulate the CSF flow between the subarachnoid space and the superior sagittal sinus, in essence, substituting for the obstructed arachnoid granulations. The valve, operating in a fully passive manner, utilizes the hydrogel swelling feature to create nonzero cracking pressure, P_T ≈ 47.4 ± 6.8 mmH₂O, as well as minimize reverse flow leakage, Q_O ≈ 0.7 μL/min on benchtop experiments. The additional measurements performed in realistic experimental setups using a fixed sheep brain also deliver comparable results, P_T ≈ 113.0 ± 9.8 mmH₂O and Q_O ≈ 3.7 μL/min. In automated loop functional tests, the valve maintains functionality for a maximum of 1536 cycles with the P_T variance of 44.5 mmH₂O < P_T < 61.1 mmH₂O and negligible average reverse flow leakage rates of ∼0.3 μL/min.

De Novo Variants Disrupting the HX Repeat Motif of ATN1 Cause a Recognizable Non-Progressive Neurocognitive Syndrome

Polyglutamine expansions in the transcriptional co-repressor Atrophin-1, encoded by ATN1, cause the neurodegenerative condition dentatorubral-pallidoluysian atrophy (DRPLA) via a proposed novel toxic gain of function. We present detailed phenotypic information on eight unrelated individuals who have de novo missense and insertion variants within a conserved 16-amino-acid "HX repeat" motif of ATN1. Each of the affected individuals has severe cognitive impairment and hypotonia, a recognizable facial gestalt, and variable congenital anomalies. However, they lack the progressive symptoms typical of DRPLA neurodegeneration. To distinguish this subset of affected individuals from the DRPLA diagnosis, we suggest using the term CHEDDA (congenital hypotonia, epilepsy, developmental delay, digit abnormalities) to classify the condition. CHEDDA-related variants alter the particular structural features of the HX repeat motif, suggesting that CHEDDA results from perturbation of the structural and functional integrity of the HX repeat. We found several non-homologous human genes containing similar motifs of eight to 10 HX repeat sequences, including RERE, where disruptive variants in this motif have also been linked to a separate condition that causes neurocognitive and congenital anomalies. These findings suggest that perturbation of the HX motif might explain other Mendelian human conditions.

Miniaturized passive hydrogel check valve for hydrocephalus treatment

Improvements in cerebrospinal fluid (CSF) draining techniques for treatment of hydrocephalus are urgently sought after to substitute for current CSF shunts that are plagued by high failure rates. The passive check valve aims to restore near natural CSF draining operations while mitigating possible failure mechanisms caused by finite leakage or low resilience that frequently constrain practical implementation of miniaturized valves. A simple hydrogel diaphragm structures core passive valve operations and enforce valve sealing properties to substantially lower reverse flow leakage. Experimental measurements demonstrate realization of targeted cracking pressures (PT ≈ 20-110 mmH2O) and operation at -800 <; ΔP <; 600 mmH2O without observable degradation or leakage.

Supracerebellar infratentorial endoscopically controlled resection of pineal lesions: case series and operative technique

OBJECT

The heterogeneous clinical manifestations and operative characteristics of pathological entities in the pineal region represent a significant challenge in terms of patient selection and surgical approach. Traditional surgical options have included endoscopic transventricular resection; open supratentorial microsurgical approaches through the midline, choroidal fissure, lateral ventricle, and tentorium; and supracerebellar infratentorial (SCIT) approaches through the posterior fossa. The object of the current study was to review the preoperative characteristics and outcomes for a cohort of patients treated purely via the novel endoscopically controlled SCIT approach.

METHODS

A single-institution series of 9 consecutive patients (4 male and 5 female patients [10 total cases]; mean age 21 years, range 6-37 years) treated via the endoscopically controlled SCIT approach for a pathological entity in the pineal region was retrospectively reviewed. The mean follow-up time was 13.2 months.

RESULTS

The endoscopically controlled SCIT approach was successfully used to approach a variety of pineal lesions, including pineal cysts (6 patients), epidermoid tumor, WHO Grade II astrocytoma (initial biopsy and recurrence), and malignant mixed germ cell tumor (1 patient each). Gross-total resection and/or adequate cyst fenestration was achieved in 8 cases. Biopsy with conservative debulking was performed for the single case of low-grade astrocytoma and again at the time of recurrence. The mean preoperative tumor and cyst volumes were 9.9 ± 4.4 and 3.7 ± 3.2 cm(3), respectively. The mean operating times were 212 ± 71 minutes for tumor cases and 177 ± 72 minutes for cysts. Estimated blood loss was less than 150 ml for all cases. A single case (pineal cyst) was converted to an open microsurgical approach to enhance visualization. There were no operative complications, as well as no documented CSF leaks, additional CSF diversion procedures, or air emboli. Seven patients underwent concomitant third ventriculostomy into the quadrigeminal cistern. At the time of the last follow-up evaluation, all patients had a stable or improved modified Rankin Scale score.

CONCLUSIONS

The endoscopically controlled SCIT approach may be used for the biopsy and resection of appropriately selected solid tumors of the pineal region, in addition to the fenestration and/or resection of pineal cysts. Preoperative considerations include patient presentation, anticipated disease and vascularity, degree of local venous anatomical distortion, and selection of optimal paramedian trajectory.

Treatment options for third ventricular colloid cysts: comparison of open microsurgical versus endoscopic resection

OBJECTIVE

We retrospectively reviewed our experience treating third ventricular colloid cysts to compare the efficacy of endoscopic and transcallosal approaches.

METHODS

Between September 1994 and March 2004, 55 patients underwent third ventricular colloid cyst resection. The transcallosal approach was used in 27 patients; the endoscopic approach was used in 28 patients. Age, sex, cyst diameter, and presence of hydrocephalus were similar between the two groups.

RESULTS

The operating time and hospital stay were significantly longer in the transcallosal craniotomy group compared with the endoscopic group. Both approaches led to reoperations in three patients. The endoscopic group had two subsequent craniotomies for residual cysts and one repeat endoscopic procedure because of equipment malfunction. The transcallosal craniotomy group had two reoperations for fractured drainage catheters and one operation for epidural hematoma evacuation. The transcallosal craniotomy group had a higher rate of patients requiring a ventriculoperitoneal shunt (five versus two) and a higher infection rate (five versus none). Intermediate follow-up demonstrated more small residual cysts in the endoscopic group than in the transcallosal craniotomy group (seven versus one). Overall neurological outcomes, however, were similar in the two groups.

CONCLUSION

Compared with transcallosal craniotomy, neuroendoscopy is a safe and effective approach for removal of colloid cysts in the third ventricle. The endoscope can be considered a first-line treatment for these lesions, with the understanding that a small number of these patients may need an open craniotomy to remove residual cysts.

The role of neurosurgery in status epilepticus

INTRODUCTION

Status epilepticus remains a life-threatening condition that afflicts both adults and children which although occurs in patients with epilepsy, often presents as new-onset seizure activity also. Refractory status epilepticus poses a management challenge for neurological and neurosurgical teams.

CASE REPORT AND METHODS

Subdural grid electrodes were used to record cortical discharges and guide tumor resection involving eloquent cortex and multiple subpial transections in a 48-year-old man with left hemiparesis in status epilepticus. He had been refractory to multiple medical therapies in persistent epilepsia partialis continua for a prolonged period. As an alternative to higher-dose suppressive medical therapy, the patient elected to proceed with subdural grid mapping after seizure semiology ("negative" scalp electroencephalogram) localized the seizure focus to the right hemisphere, motor cortex. Following tumor removal, multiple subpial transections were subsequently performed over large areas of the motor and sensory strips and successfully resolved the status epilepticus.

RESULTS

The patient made an excellent recovery, became seizure free, had improved left-sided strength and was discharged home shortly after.

CONCLUSION

This case illustrates a potentially life-saving technique for the treatment of refractory status epilepticus. Multiple subpial transections and other neurosurgical intervention should be considered for patients with status epilepticus. When localization with surface electrodes is poor, especially in eloquent cortex, subdural grid recording can be used to direct focal resection and/or multiple subpial transections to minimize neurological deficits. A review and summary of previously published neurosurgery cases for status epilepticus is discussed.

TREATMENT OPTIONS FOR THIRD VENTRICULAR COLLOID CYSTS

OBJECTIVE

We retrospectively reviewed our experience treating third ventricular colloid cysts to compare the efficacy of endoscopic and transcallosal approaches.

METHODS

Between September 1994 and March 2004, 55 patients underwent third ventricular colloid cyst resection. The transcallosal approach was used in 27 patients; the endoscopic approach was used in 28 patients. Age, sex, cyst diameter, and presence of hydrocephalus were similar between the two groups.

RESULTS

The operating time and hospital stay were significantly longer in the transcallosal craniotomy group compared with the endoscopic group. Both approaches led to reoperations in three patients. The endoscopic group had two subsequent craniotomies for residual cysts and one repeat endoscopic procedure because of equipment malfunction. The transcallosal craniotomy group had two reoperations for fractured drainage catheters and one operation for epidural hematoma evacuation. The transcallosal craniotomy group had a higher rate of patients requiring a ventriculoperitoneal shunt (five versus two) and a higher infection rate (five versus none). Intermediate follow-up demonstrated more small residual cysts in the endoscopic group than in the transcallosal craniotomy group (seven versus one). Overall neurological outcomes, however, were similar in the two groups.

CONCLUSION

Compared with transcallosal craniotomy, neuroendoscopy is a safe and effective approach for removal of colloid cysts in the third ventricle. The endoscope can be considered a first-line treatment for these lesions, with the understanding that a small number of these patients may need an open craniotomy to remove residual cysts.

Segmental spinal dysgenesis: report of four cases and proposed management strategy

INTRODUCTION

Segmental spinal dysgenesis, a rare developmental malformation, usually manifests during pregnancy or at birth. The resulting gross spinal instability necessitates spinal stabilization, which is inherently challenging in neonates.

METHODS

We report four cases of segmental dysgenesis: three in the thoracolumbar region and one at the cervicothoracic junction. The latter was maintained in a custom orthosis that restricted all craniospinal motion while allowing routine care. Two neonates underwent surgical stabilization. The fourth patient will remain in a brace until 12-14 months old when fusion is planned.

RESULTS

Fusion with rib autografts failed in the two neonates. One patient has been followed for 13 years and is paraplegic. The second patient was lost to follow up. The patient with the cervicothoracic dysgenesis maintained normal neurologic function until his death at 8 months of cardiac failure. The fourth patient is 12 months old and has been maintained in a thoracolumbar orthosis with stable neurologic function.

CONCLUSION

Several factors contribute to the challenge of creating a stable fusion in neonates. Incomplete ossification of the vertebral bodies and poor results with allograft materials restrict fusion options. Neurologic deficits often prevent ambulation and decrease the axial-loading forces that enhance fusion. To allow children to grow and develop, we advocate rigid spinal immobilization for 12-18 months before spinal fusion (preferably, rib or fibular autograft). Given the already narrow spinal canal, the use of instrumentation is controversial. We advocate the use of instrumentation in infants only when a sound construct cannot be obtained with the graft alone.

Arachnoid cysts: spontaneous resolution distinct from traumatic rupture. Case report

Although many arachnoid cysts are discovered incidentally and require no intervention, a small subset has been known to rupture. Note that rupture can occur either spontaneously or in association with trauma. Based on a review of the literature on ruptured arachnoid cysts, it appears that patients with middle fossa cysts are more likely to experience symptomatic traumatic rupture than those with cysts in other locations. Middle fossa cysts are more commonly associated with hemispheric subdural collections and hematomas than are any other cysts. The authors report on two representative cases illustrating the distinct presentation, imaging characteristics, and management of these cysts.

Invasive intracerebral schwannoma mimicking meningioma in a child

CASE REPORT

An 8-year-old boy presented to the emergency department after a generalized tonic-clonic seizure that lasted for 5 min. Magnetic resonance imaging showed a 2x2 cm, intraaxial, contrast-enhanced cortical lesion in the posterior right frontal lobe. On several images the lesion appeared to be dural-based and was presumed to be a meningioma. The patient was placed on dilantin and returned 1 month later for elective surgical resection.

OUTCOME

At surgery, a rim of intact pia was identified between the dura and the tumor. Although initial frozen-section analysis was consistent with meningioma, subsequent immunohistochemical staining and review at an outside institution established the diagnosis of intracerebral schwannoma. The patient's postoperative course was uncomplicated and he remains seizure-free with no sign of recurrence at 18 months.

CONCLUSION

Intracerebral schwannomas are uncommon cortical lesions in children. Imaging characteristics alone can be misleading; neuropathological support is essential for accurate diagnosis.

Surgical management of arteriovenous malformations in children

OBJECT

Children compose 3 to 20% of the patients with arteriovenous malformations (AVMs); however, AVMs are responsible for 30 to 50% of intracranial hemorrhages in children.

METHODS

The medical records of 82 children with 84 AVMs treated surgically between 1983 and 2005 were reviewed. Fifty-two patients (63%) presented with hemorrhage, 13.4% presented with seizures, and AVMs in 12% were found incidentally. Patients with brainstem lesions presented at a significantly younger age (p = 0.002) than those harboring lesions in other locations. Frontal lobe lesions were significantly smaller than those in other locations, and thalamic lesions were significantly larger (p = 0.012 and 0.005, respectively). Most patients with Spetzler-Martin Grades I to III lesions underwent craniotomy only. Half of the patients with Grade IV and V lesions underwent embolization, craniotomy, and radiosurgery. The mean follow-up period was 43 months. Postoperatively, the initial obliteration rate was 65%, with a long-term obliteration rate of 90%. The perioperative mortality rate was 3.7%. Altogether, 81% of patients had excellent outcomes, and patients with Grade I lesions had the best outcomes. Of the 52 patients who presented with hemorrhage, 17% had fair or poor outcomes. The recurrence rate was 5.6%.

CONCLUSIONS

Children with AVMs may be more prone than adults to present with a hemorrhage and to experience recurrence of the lesion after treatment. The authors favor resection for most AVMs in children and use embolization as a preoperative strategy for Grades II to V lesions treated surgically. Prehemorrhagic Grade IV and V lesions may best be treated conservatively and observed carefully for the development of symptoms. Long-term follow up of all patients is essential.

Spinal cord compression from traumatic anterior cervical pseudomeningoceles

✓Pseudomeningoceles rarely develop after cervical trauma; in all reported cases the lesions have extended outside the spinal canal.

The authors report the first known cases of anterior cervical pseudomeningoceles contained entirely within the spinal canal and causing cord compression and neurological injury. The authors retrospectively reviewed the cases of three patients with traumatic cervical spine injuries and concomitant compressive anterior pseudomeningoceles. The lesion was recognized in the first case when the patient’s neurological status declined after he sustained a severe atlantoaxial injury; the pseudomeningocele was identified intraoperatively and decompressed. After the decompressive surgery, the patient’s severe tetraparesis partially resolved. In the other two patients diagnoses of similar pseudomeningoceles were established by magnetic resonance imaging. Both patients were treated conservatively, and their mild to moderate hemiparesis due to the pseudomeningocele-induced compression abated.

The high incidence of anterior cervical pseudomeningoceles seen at the authors’ institution within a relatively brief period suggests that this lesion is not rare. The authors believe that it is important to recognize the compressive nature of these lesions and their potential to cause devastating neurological injury.

Management of cranial base chondrosarcomas

OBJECTIVE

Chondrosarcomas are rare, infiltrative, progressive lesions that occur at the cranial base. Their intimate association with cranial nerves and major vessels of the head and neck often precludes complete surgical resection.

METHODS

Between 1983 and 2003, 23 patients (14 females, 9 males) were treated at our institution with the diagnosis of chondrosarcoma of the cranial base (mean age at presentation, 43 yr). A retrospective chart review was performed to evaluate presentation, management, and adjunctive treatment. All living patients were contacted for a current examination and disease status.

RESULTS

The 23 patients underwent 43 surgical resections. Follow-up ranged from 8 months to 25 years (mean, 97 mo). Ten patients underwent various adjuvant radiation therapies. Five patients have died. Four patients have no evidence of disease, and 13 have residual tumor. One was lost to follow-up. Of 14 patients with 5 years of follow-up, 13 are living. Therefore, the absolute 5 year survival rate is 93%. The 10 year survival rate is 71%.

CONCLUSION

Because of the intricate nature of the cranial base, a team approach is preferable for managing these challenging lesions. Maximum cytoreductive surgery should be pursued as an initial strategy to minimize neurological injury. Adjuvant stereotactic radiosurgery can be used to treat residual disease or small recurrences. This cohort also illustrates that patients with chondrosarcomas have better long-term survival rates than patients with chordomas of the cranial base.

The evolution of endovascular treatment for intracranial arteriovenous malformations

✓ Endovascular therapy for arteriovenous malformations (AVMs) remains a relatively new approach. Beginning in the 1960s with the use of flow-directed techniques for selective embolization, hemodynamic alterations have been used to treat these lesions. In every aspect of treatment, technological advances, including catheters, embolic materials, angiography suites, and pharmacological agents, have improved outcomes while lowering the risk to patients.

In this article, the authors review the technical evolution of endovascular AVM therapy. Developments in embolic materials, beginning with foreign bodies and autografts and continuing through to highly engineered contemporary substances, are discussed. Finally, changes in treatment paradigms that have occurred over the years are traced. Within neurosurgery, this specialty has shown some of the fastest growth and development in recent decades. As minimally invasive approaches are embraced in all areas of medicine, it is clear that this treatment modality will continue to be refined.

Bedside twist drill craniostomy for chronic subdural hematoma: a comparative study

BACKGROUND

Although the bedside twist drill craniostomy is used to treat chronic subdural hematomas, the efficacy of this technique has not been compared with that of standard treatments (operative bur hole or craniotomy).

METHODS

Twist drill craniostomy was compared with operative bur hole or craniotomy in a prospective nonrandomized trial. The inclusion criteria were computed tomographic evidence of chronic subdural hematoma (isodense or hypodense compared with brain) and symptoms indicating the need for drainage. Selection of the procedure depended on the on-call surgeon's preference. Clinical success of the procedure, recurrence, length of hospitalization, complications, and neurologic outcome were compared.

RESULTS

Between August 2001 and October 2002, 79 consecutive patients with 91 chronic subdural hematomas were treated (67 unilateral and 12 bilateral) at our institution. Fifty-five patients were treated with twist drill craniostomy and 24 with bur hole or craniotomy. There were no differences in the mean age of presentation, thickness of hematoma, length of hospitalization, reoperation rate, mortality rates, or ability to be discharged to home between the 2 groups. There was no difference in the neurologic outcomes in the 57 of the 79 patients available for follow-up.

CONCLUSIONS

Twist drill craniostomy performed at the bedside is just as effective in treating chronic subdural hematomas as bur holes or craniotomy in the operating room. This procedure can most often be the first line of treatment in patients with symptomatic chronic subdural hematomas.

De novo presentation of an arteriovenous malformation. Case report and review of the literature

The authors report the case of a patient with a de novo arteriovenous malformation (AVM), indicating that the origin of these lesions may not always be congenital. A 3-year-old girl who was struck by a car suffered a mild head injury and experienced posttraumatic epilepsy. The initial magnetic resonance (MR) image obtained in this child revealed only a small contusion in the left frontal lobe. Intractable epilepsy subsequently developed. A second MR image obtained almost 4 years after the injury demonstrated an AVM in the right posterior temporal lobe that was verified using angiography. The lesion was classified as a Spetzler-Martin Grade III AVM. The patient underwent embolization of the feeding vessels followed by gamma knife surgery. Fourteen months after treatment she was asymptomatic. Follow-up MR images demonstrate no evidence of an AVM and no changes in the white matter. This case presents a de novo AVM that developed within approximately 4 years. The findings indicate that AVMs may not always be congenital and reinforce the concept that the natural history of AVMs is dynamic. Lesions may appear de novo, grow, and thrombose spontaneously.

The effects of craniosynostosis on the brain with respect to intracranial pressure

Intracranial pressure (ICP) and skull volume are intricately related. Craniosynostosis alters skull volume, and the many forms of craniosynostosis complicate the relationship to ICP even further. Patients with single-suture synostosis are less likely to experience elevated ICP than patients in whom multiple sutures, craniofacial syndromes, or both are involved. Among patients with more than one suture involved, the multifactorial mechanisms underlying elevated ICP include cephalocranial disproportion and venous outflow obstruction. Direct monitoring of ICP for at least 24 hours can aid in the diagnosis and decision making process. The management of craniosynostotic patients is diverse and necessitates a long-term plan for follow-up.

Cognitive impact of craniosynostosis

This article reviews the data on the effects of synostosis on cognitive development and the role of surgical intervention in ameliorating these effects. The literature on children with single-suture craniosynostosis, treated both surgically and conservatively, is reviewed. The evidence for possible pathophysiological mechanisms by which brain restriction might affect cognitive development is also reviewed. Although children with single-suture isolated craniosynostosis may be at risk of developmental delay, learning disability, or both, especially with regard to speech or language skills, available testing methodologies provide no evidence of an association between surgical intervention and ultimate intellectual outcome. Despite the controversies about the role of surgery in addressing the cognitive sequelae of simple craniosynostosis, in the absence of definitive data, the indications for surgery include correction of deformity and minimization of cognitive sequelae. The relative risks of performing surgery early or late must be determined on an individual basis, balancing potential cosmetic and cognitive benefits against the heightened risk of reoperation or perioperative morbidity.

Non-uniformity of contact stress on polyethylene inserts in total knee arthroplasty

This study examined tibiofemoral contact stresses in 15 commercially available TKR designs, using digitally imaged pressure-sensitive film. The objectives were (1) to determine the correlation between minimization of spatial mean contact stress and minimization of the amount of overloaded (>10 MPa) polyethylene contact area, and (2) to ascertain the difference in contact stresses for machined versus moulded polyethylene inserts. The data showed that there was no statistically significant (design rank-order) correlation of spatial mean contact stress with overloaded polyethylene area. The data also showed that machining cutter preparation of the polyethylene insert caused substantial local contact stress non-uniformities that corresponded to the pattern of grossly visible machining marks.