Preoperative Evaluation of Craniopagus Twins: Anatomy, Imaging Techniques, and Surgical Management

Craniopagus twins are a rare congenital malformation in which twins are conjoined at the head. Although there is high prenatal and postnatal mortality for craniopagus twins, successful separation has become more common due to advances in neuroimaging, neuroanesthesia, and neurosurgical techniques. Joined brain tissue, shared arteries and veins, and defects in the skull and dura make surgery technically challenging, and neuroimaging plays an important role in preoperative planning. Drawing on our experience from consultation for multiple successful separations of craniopagus twins, we discuss what radiologists need to know about the anatomy, classification, imaging techniques, and surgical management of craniopagus twins.

Diffusion tensor imaging and ventricle volume quantification in patients with chronic shunt-treated hydrocephalus: a matched case-control study

OBJECTIVEThe object of this study was to use diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS) to characterize the long-term effects of hydrocephalus and shunting on white matter integrity and to investigate the relationship of ventricular size and alterations in white matter integrity with headache and quality-of-life outcome measures.METHODSPatients with shunt-treated hydrocephalus and age- and sex-matched healthy controls were recruited into the study and underwent anatomical and DTI imaging on a 3-T MRI scanner. All patients were clinically stable, had undergone CSF shunt placement before 2 years of age, and had a documented history of complaints of headaches. Outcome was scored based on the Headache Disability Inventory and the Hydrocephalus Outcome Questionnaire. Fractional anisotropy (FA) and other DTI-based measures (axial, radial, and mean diffusivity; AD, RD, and MD, respectively) were extracted in the corpus callosum and internal capsule with manual region-of-interest delineation and in other regions with TBSS. Paired t-tests, corrected with a 5% false discovery rate, were used to identify regions with significant differences between patients and controls. Within the patient group, linear regression models were used to investigate the relationship between FA or ventricular volume and outcome, as well as the effect of shunt-related covariates.RESULTSTwenty-one hydrocephalus patients and 21 matched controls completed the study, and their data were used in the final analysis. The authors found significantly lower FA for patients than for controls in 20 of the 48 regions, mostly posterior white matter structures, in periventricular as well as more distal tracts. Of these 20 regions, 17 demonstrated increased RD, while only 5 showed increased MD and 3 showed decreased AD. No areas of increased FA were observed. Higher FA in specific periventricular white matter tracts, tending toward FA in controls, was associated with increased ventricular size, as well as improved clinical outcome.CONCLUSIONSThe study shows that TBSS-based DTI is a sensitive technique for elucidating changes in white matter structures due to hydrocephalus and chronic CSF shunting and provides preliminary evidence that DTI may be a valuable tool for tailoring shunt procedures to monitor ventricular size following shunting and achieve optimal outcome, as well as for guiding the development of alternate therapies for hydrocephalus.

The history of intracranial infections

The 19th and 20th centuries heralded the advancement of our understanding of surgical infections, reducing the risk of morbidity and mortality to patients by overturning long-held dogmas surrounding infections and perioperative care. These advancements impacted the development and establishment of the field of neurological surgery by minimizing surgical risk through aseptic techniques and promoting surgical benefit via improved neurological localization and surgical technique. Infections were significant contributors to morbidity and mortality for all surgical patients, and historically almost half of patients lost their lives as a consequence of perioperative wound contamination. With advancing understanding of germ theory, contagion, antisepsis, and subsequently asepsis, the surgeon began embracing the knowledge and techniques which would hone their craft and allow for a renaissance in the management of neurological disorders in an unprecedented manner.

Neurointerventional participation in craniopagus separation

Craniopagus-type conjoined twins (joined at the head) are exceedingly rare. Separation of craniopagus conjoined twins is a challenging task mainly owing to complex vascular anatomy and limited experience with this disorder. Modern neuroimaging techniques including digital subtraction angiography can be used to preoperatively assess the cerebral vascular system. These techniques can also provide the raw data to fabricate three-dimensional true-scale models. We report a case in which endovascular techniques have been used in the separation of craniopagus conjoined twins. To our knowledge there are no reports of successful incorporation of neurointerventional methods in the disconnection of shared venous channels.

Use of a customized 3D "basket" to create a solitary split-thickness cranial graft from numerous split fragments in an infant

While autologous split calvaria remains the preferred material for use in pediatric cranioplasty, it may be difficult to split the bone neatly into two distinct pieces, especially in infants and young children. In this paper, the authors present a technique in which numerous split pieces of bone can be readily joined together and conformed to the shape of the specific defect using a customized template and 3D trellis-like basket.

Successful treatment of post-shunt craniocerebral disproportion by coupling gradual external cranial vault distraction with continuous intracranial pressure monitoring

A subset of hydrocephalic patients in whom shunts are placed at an early age will develop craniocerebral disproportion (CCD), an iatrogenic mismatch between the fixed intracranial volume and the growing brain. The lack of a reliable, reproducible method to diagnose this condition, however, has hampered attempts to treat it appropriately. For those practitioners who acknowledge the need to create more intracranial space in these patients, the lack of agreed-upon therapeutic end points for cranial vault expansion has limited the use of such techniques and has sometimes led to problems of underexpansion. Here, the authors present a definition of CCD based primarily on the temporal correlation of plateau waves on intracranial pressure (ICP) monitoring and headache exacerbation. The authors describe a technique of exploiting continued ICP monitoring during progressive cranial expansion in which the goal of distraction is the cessation of plateau waves. Previously encountered problems of underexpansion may be mitigated through the simultaneous use of ICP monitors and gradual cranial expansion over time.

Infections of the spinal subdural space in children: a series of 11 contemporary cases and review of all published reports. A multinational collaborative effort

INTRODUCTION

Positioned anatomically between the spinal epidural space and the intramedullary compartment, the spinal subdural space remains the least common area of localized infection in the central nervous system. Infectious processes of the subdural spinal space include subdural spinal empyema, subdural spinal abscess, infected spinal subdural cyst, and infectious spinal subdural cyst. To date, there has been no systematic review of these entities in children, with the cumulative knowledge of the pathophysiologic, microbiologic, and demographic characteristics of these infections relegated solely to few small series and case reports.

METHODS

A series of 11 recent cases culled from the collaboration of international authors are presented. In addition, an exhaustive MEDLINE search and manual review of the international literature was performed, identifying a total of 73 cases of spinal subdural infections in patients under the age of 21. Data of interest include the age, sex, signs, and symptoms at presentation, spinal location of infection, presence of spinal dysraphism, and other comorbidities, offending organism, treatment, outcome, and follow-up.

RESULTS

Patients ages ranged from 4 weeks to 20 years (mean, 6.5 years). Males outnumbered females by a ratio of 2:1. Over half (53 %) of spinal subdural infections in children were associated with spinal dysraphism or other congenital abnormalities of the spine. The commonest organism to infect the spinal subdural space in children is mycobacterium tuberculosis and the thoracic spinal region was most commonly infected.

CONCLUSIONS

The disease is usually treated surgically, although a more expectant approach consisting of antibiotics and observation has also been proposed.

Marvelous medicine: the untold story of the Wade-Dahl-Till valve

On December 5, 1960, 4-month-old Theo Dahl, the only son of best-selling author Roald Dahl (1916-1990), had his skull shattered in a horrific traffic accident. What began as a personal tragedy for the Dahl family would soon evolve into a dogged crusade by Dahl to expand upon preexisting valve technology with the goal of developing a shunt that would not become obstructed. Based upon exclusive access to private archives of the Dahl estate, as well as interviews with those involved, this article tells the intricate tale of one famous father's drive to significantly alter the natural history of pediatric hydrocephalus. Dahl's collaboration with British toymaker Stanley Wade and pioneering pediatric neurosurgeons Joseph Ransohoff, Kenneth Shulman, and Kenneth Till to create the Wade-Dahl-Till (WDT) valve is examined in detail. The ensuing rift between the American and British contingents, the valve's multiple design revisions, and the goal of creating an affordable shunt for children in developing countries are among the issues addressed. The development of the WDT valve marked a significant turning point in the surgical management of pediatric hydrocephalus in general and in shunt valve technology in particular.

Interparietal bone (Os Incae) in craniosynostosis

The interparietal bone, Os Incae, is formed in a persistent mendosal suture. This suture is a normal variant in the human skull, well-known in anatomy and radiology textbooks. We report 11 children with craniosynostosis in the presence of an interparietal bone, five from Children's Hospital at Montefiore and six children from Children's Hospital Boston. The true incidence of an interparietal bone in patients with craniosynostosis or craniofacial anomalies is not known; nor are there recognized sequelae of an interparietal bone (bathrocephaly). Hypotheses regarding mechanisms that may contribute to the formation of an interparietal bone are discussed.

Anatomy, technology, art, and culture: toward a realistic perspective of the brain

In the 15th century, brain illustration began to change from a schematic system that involved scant objective rendering of the brain, to accurate depictions based on anatomical dissections that demanded significant artistic talent. Notable examples of this innovation are the drawings of Leonardo da Vinci (1498–1504), Andreas Vesalius' association with the bottega of Titian to produce the drawings of Vesalius' De humani corporis fabrica (1543), and Christopher Wren's illustrations for Thomas Willis' Cerebri Anatome (1664). These works appeared during the Renaissance and Age of Enlightenment, when advances in brain imaging, or really brain rendering, reflected not only the abilities and dedications of the artists, but also the influences of important cultural and scientific factors. Anatomy and human dissection became popular social phenomena as well as scholarly pursuits, linked with the world of the fine arts. The working philosophy of these artists involved active participation in both anatomical study and illustration, and the belief that their discoveries of the natural world could best be communicated by rendering them in objective form (that is, with realistic perspective). From their studies emerged the beginning of contemporary brain imaging. In this article, the authors examine how the brain began to be imaged in realism within a cultural and scientific milieu that witnessed the emergence of anatomical dissection, the geometry of linear perspective, and the closer confluence of art and science.

Endovascular transvenous embolization of sinus pericranii. Case report

Sinus pericranii (SP) is an abnormal communication between the intra- and extracranial venous drainage pathways. Treatment of this condition has mainly been recommended for reasons of cosmesis and prevention of hemorrhage. The authors report a novel endovascular transvenous route for definitive treatment of SP.

Craniopagus twins

Craniopagus twins represent a rare phenomenon of congenital misfortune. Modern neurosurgical techniques have created opportunities for successful separation and the promise of a normal existence for these children, who in the past were often left as historical footnotes or put on display as oddities of nature. The authors document a brief history of conjoined twinning and discuss the modern science of craniopagus epidemiology, classification, and separation. In particular, the strategies used and the rationale for staged surgical separation are highlighted.

Rare C-6 vertebral involvement in a child with histiocytosis X: case report

The authors present a rare case of C-6 vertebral involvement in a 12-year-old boy with histiocytosis X. The patient presented with limitation in movements of neck and upper extremities. Computed tomography (CT) and magnetic resonance (MRI) imaging were used in the preoperative workup. Surgery was performed via an anterior cervical approach along with stabilization using a fibula strut graft and plate fixation. Pathological assessment showed infiltration of Langerhans cells accompanied by a mixture of many eosinophils, giant cells, neutrophils and foamy cells. The patient went on to make a full recovery with complete resolution of his motor weakness. In an extensive review of the literature there are very few cases of cervical histiocytosis X reported. In addition, surgical management of this type of lesion has rarely been discussed.

The craniopagus malformation: classification and implications for surgical separation

Craniopagus twins (CPT) are an uncommon, highly fascinating accident of nature. The clinical pathology of this complex entity is reviewed and placed in perspective. A logical classification aids understanding of the anomaly, and is essential to gauge outcome from separation attempts. 'Partial forms' lack significant shared dural venous sinuses (SDVS) and 'Total forms' with SDVS also exhibit more severe compressional brain distortion. Our classification consists of Partial Angular (PA), Partial Vertical (PV), Total Angular (TA) and Total Vertical (TV, formerly O'Connell Types I-III). Total vertical has a continuous cranium, and inter-twin axial facial rotation <40 degrees (Type I), 140-180 degrees (Type II) or intermediate (Type III). The term 'Angular' denotes an inter-twin longitudinal angle below 140 degrees , regardless of axial rotation. Our review categorized 64 well-delineated CPT, including 41 operative separation attempts in small children since initial success in 1952. Just over one-half were TV, almost one-third TA, and partial forms accounted for the remaining one-sixth. About 30% of CPT had shared or fused brain tissue, and a similar percentage of TA twins shared a posterior fossa. Partial forms had significantly higher birth weights, were separated at an earlier age (6 versus 11 months) and had lower mortality and better outcome compared with Total forms. A multi-staged surgical separation for Total CPT had a significantly better mortality than single-staged separation. Discussion emphasizes embryological, anatomical and clinical aspects of the malformation, with emphasis upon obstacles to a successful outcome.

Separation of craniopagus conjoined twins: an evolution in thought

Advances in medicine have enabled more craniopagus twins to survive separation, but the ultimate goal, to have both twins emerge from their separation with full neurologic function and a chance at leading independent and productive lives, remains elusive. The authors were contacted to evaluate craniopagus conjoined male infant twins for separation. Once it was determined that the brains were separate, they reviewed the literature and elected to design an open-ended multistaged separation. Four major stages over 9 and a half months led to the successful separation and preservation of neurologic function. To the authors' knowledge, this is the first such outcome in such a case. This article reviews the pertinent literature and discusses the authors' rationale and methodology.

Contemporary psychosurgery and a look to the future

OBJECT

Despite a long and controversial history, psychosurgery has persisted as a modern treatment option for some severe, medically intractable psychiatric disorders. The goal of this study was to review the current state of psychosurgery.

METHODS

In this review, the definition of psychosurgery, patient selection criteria, and anatomical and physiological rationales for cingulotomy, subcaudate tractotomy, anterior capsulotomy, and limbic leukotomy are discussed. The historical developments, modern procedures, and results of these four contemporary psychosurgical procedures are also reviewed. Examples of recent advances in neuroscience indicating a future role for neurosurgical intervention for psychiatric disease are also mentioned.

CONCLUSIONS

A thorough understanding of contemporary psychosurgery will help neurosurgeons and other physicians face the ethical, social, and technical challenges that are sure to lie ahead as modern science continues to unlock the secrets of the mind and brain.

Psychosurgery: a historical overview

Neurosurgical treatment for psychiatric disorders has a long and controversial history. From the Stone Age use of trephining to release the demons of the spirit to the millimeter accuracy of stereotactic instruments currently used in the operating room, psychosurgery has enjoyed enthusiastic support as well as experiencing scorn. Today, psychosurgery is a minimally invasive and highly selective treatment that is performed for only a few patients with severe, treatment-refractory, affective, anxiety, or obsessive-compulsive disorders. Recent advances in technology and functional neuroanatomic techniques, as well as economic pressures to decrease the costs of caring for chronically ill patients, may provide an opportunity for psychosurgery to become a more attractive option for the treatment of psychiatric diseases. In this historical overview, the rise and fall of psychosurgery are described. A better understanding of the colorful history of this interesting topic should enable modern neurosurgeons and other health care professionals to meet the social, ethical, and technical challenges that are sure to lie ahead.

An annotated history of craniofacial surgery and intentional cranial deformation

The history of craniofacial surgery and the use of intentional cranial deformation is a long and varied one. Researching some of the earliest medical writings and reviews of early terracotta and stone figures from throughout the world clearly revealed that these two forms of treatment were widely extant. Intentional cranial deformation was used for a number of reasons including beautification, tribal identification, and social stature. The development of craniofacial surgery is a more modern practice and its historical evolution is reviewed in the context of techniques and the personalities involved.

A millennium review of skull base surgery

Skull base surgery is a recent development in our history, in as much as most of the surgical techniques involved have been described within the last century. To provide an historical prospective the author reviews the development of this specialty, arbitrarily dating its beginning some five centuries ago with the work of Leonardo da Vinci. By picking this period we include the origin of scientific anatomy and personages interested in developing new ideas and concepts who were able to leave the stagnant period of the Middle Ages behind. In 1900 surgeons worked alone, with the concept of a skull base "team" not yet existing. Endotracheal intubation and controlled respiration was just being introduced. Intraoperative monitoring of blood pressure, pulse rate and respiration was not yet known. Harvey Cushing was to introduce this concept in the first decade of the last century. This survey traces the origins of modern skull base surgery from its antecedents in the Renaissance to the beginning of this century. A paper of this length can only provide a sampling of themes and personalities; nevertheless, it will give the reader an impressive overview of how far we have come and some ideas of what the future holds.

Reprint of "Concerning Surgical Intervention for the Intracranial Hemorrhages of the New-born" by Harvey Cushing, M.D. 1905

This paper was first presented at a meeting in 1905 and gives an insight into the problems faced in early neurosurgical operations in newborns and the way they were approached by an adventurous surgeon.

Fronto-ocular syndrome: newly recognized trigonocephaly syndrome

We describe an apparently unique disorder, Fronto-Ocular syndrome, present in a mother and her two daughters, and comprising trigonocephaly due to coronal and metopic craniosynostosis, ocular hypotelorism, ocular proptosis and ptosis, epicanthal folds, hypoplastic supraorbital ridges, elevated nasal bridge, thin philtrum, high-arched palate and a narrow bifrontal region. Both daughters have glabellar capillary hemangiomas, a congenital heart defect and mild developmental disabilities. Review of the literature failed to disclose any syndrome with similar findings. It is likely that this disorder represents an autosomal dominant condition, that arose as a new mutation in the mother. Mutational analysis of fibroblast growth factor receptor (FGFR) 1 and FGFR2 failed to identify the molecular basis of the disorder.

First published record of a neurosurgical procedure on the North American continent, Mexico City, by Pedro Arias de Benavides, 1561: Secretos de Chirurgia, Valladolid, Spain, 1567

The first published account of a neurosurgical intervention performed on the North American continent is described. The operation took place in Mexico City in 1561. The neurosurgical intervention was performed by a Spanish surgeon, Pedro Arias de Benavides, on a 13-year-old boy who had sustained head trauma that caused an open depressed cranial fracture and exposed the cerebrum. A description of this case was first published in Valladolid, Spain, 6 years after the event, in a book entitled Secretos de Chirurgia ("Secrets of Surgery").

The 2-piece Le Fort I osteotomy for cranial base access: an evaluation of 9 patients

PURPOSE

This article discusses the use of the 2-piece Le Fort I osteotomy to gain access to the cranial base and the authors' experiences with this technique.

METHODS

Medical records of patients who required surgical access to the cranial base were retrospectively reviewed, and demographic data, procedures done, postoperative results, and complications were recorded.

RESULTS

Nine patients underwent a 2-piece Le Fort I osteotomy. Complications included development of a pseudoaneurysm of the internal carotid artery in 1 patient, 2 cerebrospinal fluid leaks, both of which resolved, and 1 patient who lost 2 teeth and some associated bone.

CONCLUSION

The 2-piece Le Fort I osteotomy provides excellent access to the clival region of the cranial base with minimal complications.

Endoscopic intracranial craniofacial and monobloc osteotomies with the aid of a malleable high-speed pneumatic drill: a cadaveric and clinical study

Endoscopic techniques are now an accepted part of the surgical armamentarium and are used routinely in a number of aesthetic and reconstructive procedures. Endoscopic techniques are now being used commonly by plastic surgeons in forehead and face lifts. In both craniofacial surgery and in neurosurgery, the application of endoscopy potentially allows the surgical team to perform wide dissection of the dura mater in a minimally invasive fashion, thereby potentially reducing the risk of dural and brain injury. Also reduced by this surgical approach is potential injury to the major venous structures, such as the sagittal sinus, along with overall reduced bleeding. After an extensive laboratory study of 10 cadaveric dissections, the authors have refined a new endoscopic technique for completing an endoscopic intracranial craniofacial osteotomy. This study was conducted in the Department of Pathology at the University of Brno (Czech Republic), and was performed as a cooperative multicenter project between the University of Palermo, the Albert Einstein College of Medicine/ Montefiore Medical Center, the Hospital Infantil de Mexico, "Federico Gomez," and the Medtronic Midas Rex Institute, (Fort Worth, TX). During this cadaveric anatomic study and using small trephinations and skin incisions the authors were able to develop several different craniofacial and endoscopic monobloc procedures. To accomplish intracranial and facial osteotomies, a new malleable high-speed drill was designed for use in the endoscopic craniofacial approach. Using these newly developed cadaveric techniques and instrumentation, the authors performed two intracranial craniofacial procedures on children with congenital craniofacial anomalies. There would appear to be several significant advantages for the craniofacial patient as result of these new techniques: reduced surgical trauma, operative bleeding, surgical time, and hospitalization, along with a reduced risk of infection. It became quickly apparent, as a result of these cadaveric studies, that the learning curve for this endoscopic procedure is quite steep. Tutino M, Chico F, Tutino M, Goodrich JT, Ortiz Monasterio F. Endoscopic intracranial craniofacial and monobloc osteotomies with the aid of a malleable high-speed pneumatic drill: a cadaveric and clinical study.

The Edwin Smith Surgical Papyrus

The Edwin Smith Surgical Papyrus is undoubtedly one of the most significant medical texts ever discovered. It is of particular interest to neurosurgeons because of its specific references to ancient neurosurgical cases and is the first written record of many terms of neurosurgical interest. This review describes the colorful and controversial history of the Edwin Smith Papyrus and gives translations of four cases of neurosurgical interest.

Foreign body granuloma mimicking intracranial meningioma: case report and review of the literature

OBJECTIVE AND IMPORTANCE

Intracranial foreign body granulomas are rare. We describe a case of an intracranial foreign body granuloma found in a 17-year-old female patient 9 years after she underwent a craniotomy for a tumor of unknown type. Postoperative imaging of patients who have undergone neurosurgical procedures can often reveal enhancing masses, and foreign body granuloma should be included in the differential diagnosis.

CLINICAL PRESENTATION

The patient presented with a history of developmental delay, panhypopituitarism, and chronic headache. Admission resulted from an acute increase in the severity of her headache.

INTERVENTION

Imaging studies, including computed tomography and magnetic resonance imaging, demonstrated a 1.5 x 2 cm round, enhancing anterior interhemispheric mass, appearing to arise from the falx and causing mild mass effect. A nonenhancing cystic mass was also noted in the suprasellar region but was without mass effect. The patient underwent a craniotomy and removal of the anterior mass without complication, and her headache resolved. A pathological examination of the specimen confirmed the diagnosis of foreign body granuloma.

CONCLUSION

Although rare, foreign body granuloma should be included in the differential diagnosis of previously operated intracranial masses. The importance of accurate historical information and guidelines that may assist in diagnosis are discussed.

Byron Stookey: "the old lion"--an unsung giant of neurosurgery

BYRON POLK STOOKEY, an outstanding clinician and teacher, served as Director and Chief of Neurosurgery at the Neurological Institute of New York Columbia-Presbyterian Medical Center. Highlights of his clinical contributions include improved peripheral nerve and spine surgery and subtemporal trigeminal nerve section for tic douloureux. Through diverse activities in both the political and academic arenas of patient care, education, and research, stookey helped to build and strengthen neurosurgery between the world wars and helped to prepare the foundation for the accomplishments of recent decades.

Management of secondary turricephaly in craniofacial surgery

In children with syndromic craniofacial disorders, such as Crouzon and Apert syndromes, who are managed surgically, a difficult problem that can occur is secondary turricephaly. One of the more widely accepted theories as to why this deformity occurs is that a lack of skull base growth results from fusion of the basal and facial sutures. Despite initial adequate forehead and orbital bandeau advancement, many of these patients require subsequent procedures, which do not always correct the characteristics deformity. We have identified a subset of 11 syndromic children who developed this characteristic deformity of turricephaly after primary reconstruction, 6 of whom required either secondary or tertiary procedures. Only 5 patients had a good outcome with a mean follow up of 4.5 years (range 1-8 years). Our surgical methods, and our rationale for the timing of surgery are discussed, and the literature on the management of this problem is reviewed.

Lambdoid stenosis (posterior plagiocephaly) and craniofacial asymmetry: long-term outcomes

We recently reviewed our series of craniofacial cases involving lambdoid stenosis (posterior plagiocephaly) and positional deformation. We now have 22 cases (who underwent surgery) with greater than 1 year follow up (range 1-7 years). We were impressed by the potential severity of the craniofacial deformity that can occur in what is often considered a positional deformation caused either by intrauterine conditions or by postnatal positioning. To decide which children were candidates for craniofacial reconstruction, we reviewed our cases and determined what we considered were appropriate criteria for craniofacial surgery. Among the 22 patients selected for surgery, 16 patients had changes in facial characteristics secondary to skull base and petrous ridge deformation, which often led to mandibular malalignment. In addition, 11 children were found to have developed scolosis of the face, similar to that seen in anterior plagiocephaly. The long-term severity of these selected craniofacial deformities may be markedly reduced if these children are operated on early with craniofacial reconstruction techniques. The removal of the lambdoid sutures, which appears to apply a twisting or torque effect on the facial structures and skull base, assisted in the children's further normal cranial development. In the children that were operated on before 1 year of age, most of the facial asymmetry was corrected. In addition, we observed that several of the children showed correction of the malignment of the ears, a common finding in these cases. Three-dimensional reconstructions have been extremely helpful in documenting the abnormalities of the skull base and sutural patterns and in planning the surgical approaches. All the patients had either a Marchac transposition or a bandeau/forehead type reconstruction. There were no long-term complications, and the esthetic results were considered good to excellent.

Recurrent cerebral arteriovenous malformations after negative postoperative angiograms

Angiography has been considered to be the gold standard to judge the success of treatment for cerebral arteriovenous malformations (AVMs). Patients without residual nidus or early draining veins on postoperative angiograms are considered cured, with the risk of hemorrhage eliminated. A series of five patients with recurrent AVMs after negative postoperative angiography is described. All patients had hemispheric AVMs, presented initially with hemorrhage, and were between 5 and 13 years of age. Recurrence was noted 1 to 9 years later (at 12-16 years of age); after a hemorrhage in three patients, seizures in one, and on follow-up magnetic resonance imaging in one. Four patients underwent angiography that showed recurrence of the AVM at or adjacent to the original site. Three years postsurgery, the fifth patient died from a large intracerebral and intraventricular hemorrhage originating in the previous location of the AVM; however, the patient did not undergo angiography at the time of recurrence. The initial negative angiograms obtained postoperatively in these patients may be explained by postoperative spasm or thrombosis of a small residual malformation. However, in the authors' cumulative experience with 808 patients who have undergone complete surgical removal of AVMs (of whom 667 were older than 18 years of age), no case of recurrent AVM has been observed in an adult. Therefore, actual regrowth of an AVM may occur in children and could be a consequence of their relatively immature cerebral vasculature and may involve active angiogenesis mediated by humoral factors. The present findings argue against the assumption that AVMs are strictly congenital lesions resulting from failure of capillary formation during early embryogenesis. It is concluded that delayed imaging studies should be considered in children at least 1 year after their initial negative postoperative arteriogram to exclude a recurrent AVM.

Mesenchymal chondrosarcoma in anterior skull base: case report

We report the case of a 16-year-old boy who presented with mesenchymal chondrosarcoma involving the ethmoid sinus, right orbit, nasal cavity, and anterior cranial fossa. The tumor was totally resected by craniofacial surgery; the patient's postoperative course was uneventful. Microscopically, the tumor was composed of highly cellular undifferentiated small cells, alternating with zones of cartilaginous tissues. Mesenchymal chondrosarcoma is a rare, aggressive variant of chondrosarcoma, which might be encountered more frequently due to the advances in neuroimaging and surgical procedures.

Mesenchymal chondrosarcoma with secondary orbital invasion

Orbital involvement with mesenchymal chondrosarcoma is rare. Until recently, despite the young age of the affected population, exenteration was the recommended management. We report a patient with orbital invasion by mesenchymal chondrosarcoma managed surgically without exenteration. Adjuvant chemotherapy and radiotherapy were administered. There is no evidence of local or distant tumor recurrence with 30 months of postoperative follow-up. This and other recent case reports suggest that exenteration may not be necessary for local tumor control of mesenchymal chondrosarcoma in the orbit.