Biomedical subjects

W J Oakes

Publications and source records attributed to W J Oakes.

At least 37 records · Page 2Linked to original sources

PubMed2001

Sagittal suture as an external landmark for the superior sagittal sinus.

OBJECT: Historically, the sagittal suture has been used as an external landmark to indicate the middle portion of the superior sagittal sinus (SSS). The goal of this study was to verify this relationship. METHODS: The authors examined 30 adult cadavers to reveal the location of the SSS with respect to the sagittal suture. Their findings demonstrated that the SSS is deviated to the right of the sagittal suture in the majority of observed specimens, although the maximum displacement to the right side was never more than 11 mm. CONCLUSIONS: This information should be useful to the neurosurgeon who must be aware of the SSS and its relationship with superficial skull landmarks.

Aged↗

PubMed2001

Surgical landmarks for the proximal portion of the axillary nerve.

OBJECT: The proximal segment of the axillary nerve (ANp) is often difficult to identify without extensive dissection deep into the axilla. The present study was performed to find reliable surgical landmarks for this nerve. METHODS: Thirty dissections of human cadavers were performed to determine the relationships between the ANp and specific anatomical structures. The authors found that the ANp is consistently located within an anatomical triangle constructed by lines passing between the coracobrachialis and pectoralis minor muscles and the axillary artery. In addition, the ANp was routinely found 4 cm distal to the coracoid process of the scapula. CONCLUSIONS: These findings should assist the surgeon in locating the ANp during brachial plexus reconstruction.

Aged↗

PubMed2001

The denticulate ligament: anatomy and functional significance.

OBJECT: The authors conducted a study to examine the detailed anatomy of the denticulate ligaments and to assess their classic role in spinal cord stability within the spinal canal. METHODS: Detailed observation of the denticulate ligaments in 12 adult cadavers was performed. Stress was applied in all major planes to discern when the ligaments would become taut, and at the same time, gross motion of the cord was observed at sites distal to the stresses applied. Tension necessary for avulsion of the ligaments in various areas of the spinal cord was also measured. CONCLUSIONS: These results show that the denticulate ligaments do not inhibit cord motion to such discrete areas of the cord as was once thought. The authors have determined that the ligaments are stronger in the cervical region and that they decrease in strength as the spinal cord descends. These findings are demonstrative of the denticulate ligaments being more resistant to caudal compared with cephalad stresses in the cord. Anterior and posterior motion is constrained by these ligaments but to a limited degree, especially as one descends inferiorly along the cord. Further embryological and functional studies of these ligaments is needed in non-formalin fixed tissues.

Aged↗

PubMed2000

Split cord malformations in myelomeningocele patients.

Split cord malformations (SCMs) may occur in conjunction with myelomeningoceles, and are often ignored or misdiagnosed, potentially causing spinal cord tethering. In this paper, we study the incidence and clinical significance of such an association. We have retrospectively reviewed the medical records and radiographs of 20 myelomeningocele patients who had a SCM. These comprised at least 6% of our myelomeningocele patients. Five of the 20 had simultaneous repair of both lesions at birth. The other 15 were diagnosed with the SCM in a delayed fashion (mean age 4.4 years). Clinical presentations that prompted a diagnostic investigation included hypertrichosis (1), pain (2), routine radiographic follow-up (2), neurourological deterioration (10) and progressive scoliosis (5). In 17 of the 20 patients, the SCM involved the placode or was within one level of it. Fifteen of these were in the area of the placode or one segment above it. Five of the 20 patients had hypertrichosis and 15 of the 20 patients had a bony midline septum (i.e. type I SCM). Several accompanying spinal dysraphic lesions also contributed to the tethering: thickened (previously inconspicuous) filum terminale (6), syringohydromyelia (5) and a neurenteric cyst with a benign teratoma (1). Arachnoiditis secondary to the prior myelomeningocele repair was found, as expected, in all 15 patients. However, in virtually all patients, there was also evidence of tethering at the level of the SCM. Long-term follow-up showed stabilization of preoperative symptoms and signs, whereas complications of the operation and clinical evidence of retethering were uncommon. Myelomeningocele patients should be screened with clinical examinations looking for hypertrichosis and with spinal radiographs preoperatively looking for evidence of SCM (bony midline septum and/or interpedicular widening not due to the myelomeningocele). Intraoperatively, the placode and the rostral spinal cord segment should be carefully inspected for an SCM and other dysraphic lesions.

Adolescent↗

PubMed2000

Urological outcome of patients with cervical and upper thoracic myelomeningocele.

PURPOSE: We determined the incidence of voiding disorders and upper tract deterioration in children with cervical and upper thoracic level myelomeningocele. MATERIALS AND METHODS: We retrospectively reviewed the neurosurgical and urological presentation, evaluation and treatment of 11 patients of whom 8 had cervical and 3 had upper thoracic myelomeningocele. There were 7 female and 4 male patients 10 months to 39 years old (mean age 12 years). All patients were ambulatory and 5 of 11 (45%) had hydrocephalus. Although a voiding history was obtained by a neurosurgeon in all patients, only 9 had undergone a formal urological evaluation, including video urodynamic assessment in 5. RESULTS: No patient had an increased post-void residual and none had ever been placed on intermittent catheterization. Tethered spinal cords from caudal fixation (thickened filum terminale and a lipomyelomeningocele) were present in 2 patients with urinary incontinence of whom 1 had recurrent cystitis. Imaging studies of the upper tracts were normal in all 9 patients and video urodynamics were normal in 3 of 5. No patient has required urological operative intervention. CONCLUSIONS: To our knowledge, this study represents the largest reported series of patients with cervical and upper thoracic myelomeningocele who have undergone urological evaluation. Our experience suggests that patients with cervical and upper thoracic myelomeningocele have a low risk of voiding disorders and upper tract deterioration unless other conditions, such as a congenital tethered cord, are present. Additional reports of children with cervical and upper thoracic myelomeningocele are necessary to confirm these findings.

Adolescent↗

PubMed2000

Neonatal ventriculosubgaleal shunts.

OBJECTIVE: We report on 32 neonates treated with ventriculosubgaleal (VSG) shunts to determine VSG shunt survival and associated complications. METHODS: Between 1993 and 1997, 37 VSG shunts were placed in 32 neonates when the cerebrospinal fluid (CSF) or the abdomen was considered unsuitable for ventriculoperitoneal shunt placement. In each child, a ventricular catheter was attached to 3 cm of a closed-end peritoneal tube via a right-angle connector, which drained into a surgically created subgaleal pocket. RESULTS: The causes of hydrocephalus were as follows: intraventricular hemorrhage (IVH) in 20 neonates, meningitis/ventriculitis in 6, IVH and infection in 2, and other causes in 4. The mean postconception age at the time of VSG shunt insertion was 37.2 weeks (33.1 wk in the IVH group), and the mean weight was 2227 g (1724 g in the IVH group). The average preoperative head circumference was 33.6 cm. The average survival of these 37 VSG shunts (five children had two VSG shunts) was 35.1 days. The complications were as follows: one CSF leakage occurred when sutures were removed; one catheter fell into the ventricle and required removal, and one child died immediately after VSG shunt revision. There were no VSG shunt infections. All surviving children followed for a minimum of 4 months after insertion of a VSG shunt (n = 24) have required a ventriculoperitoneal shunt. Mean follow-up from the time of first VSG shunt insertion was 21.6 months. Four children died as a result of causes unrelated to the VSG shunt. CONCLUSION: VSG shunts offer a simple, effective, and relatively safe means of temporizing hydrocephalus, and they avoid the need for external drainage or frequent CSF aspiration in these medically unstable infants until the CSF characteristics and abdomen are acceptable for ventriculoperitoneal shunting.

Cerebrospinal Fluid Shunts↗

PubMed2000

Genetic studies in neural tube defects. NTD Collaborative Group.

Neural tube defects (NTD) are one of the most common birth defects and are caused by both environmental and genetic factors. The approach to identifying the genes predisposing to NTD, through linkage analysis and candidate gene analysis, is reviewed along with characteristics of a large, nationally ascertained cohort of families. Results from specific assessments of p53, PAX3 and MTHFR failed to suggest that these genes play a major role in NTD development in these families. Advances in genetic laboratory and statistical techniques have made this a prime opportunity for investigation into the causes of complex disorders, such as NTD. However, traditional approaches may prove to be challenging due to the difficulty of ascertaining samplable multiplex families.

Animals↗

PubMed2000

The position of the conus medullaris in children with a Chiari I malformation.

The purpose of this study is to determine whether there is a relationship between the conus level and patients with a Chiari I malformation. This retrospective MRI study evaluated conus levels and degrees of tonsillar ectopia in 26 children ages 5-16 years with a Chiari I malformation. Our results show that there seems to be no relationship between the conus level and the amount of tonsillar ectopia that a child with a Chiari I malformation might have. In fact, there seemed to be an inverse relationship between these two entities. Interestingly, we have also found that of all coni located at the L2-L3 disc space or below, these patients had a syrinx associated with their Chiari I malformation and that all malformations without a syrinx had a 'normally' positioned conus medullaris.

Adolescent↗

PubMed2000

Coccygeal pits.

BACKGROUND: Congenital dermal sinuses represent cutaneous depressions or tracts that are lined by stratified squamous epithelium. They communicate between the surface of the skin and deeper structures and may occur anywhere along the craniospinal axis. These sinuses are thought to result from abnormal separation of the cutaneous and neural ectoderm between the third and fifth week of intrauterine life. They may be often accompanied by other cutaneous stigmata, various dysraphic abnormalities, or intraspinal tumors. In the sacrococcygeal area, cutaneous congenital abnormalities are relatively common. It is estimated that 2% to 4% of children harbor intergluteal dorsal dermal sinuses. These intergluteal sinuses in the perianal region are frequently referred to as pits or dimples. Their cause is considered similar to other congenital dermal sinuses and appears unrelated to acquired pilonidal conditions observed in adults. They may become susceptible to local recurrent infection from trauma or hirsutism. Controversy regarding the evaluation and management of cutaneous defects in the coccygeal region exists. METHODS: Both a literature review and a career review of clinical material were performed. Databases for articles published in English were surveyed for key words relating to coccygeal sinuses using standard computerized search techniques. The medical records of children presenting to our neurosurgical clinic for evaluation of dorsal dermal sinuses were reviewed to identify those with intergluteal sinuses. RESULTS: In the evaluation of reported cases and of our own, we were unable to identify any children with coccygeal sinuses without other cutaneous markers other than hair with findings suggestive of intraspinal communication. CONCLUSIONS: Intergluteal dorsal dermal sinuses are relatively common lesions that frequently come to neurosurgical attention. They do not seem to be associated with significant risk of spinal cord and intraspinal anomalies. Simple intergluteal dorsal dermal sinuses without other cutaneous findings do not require radiographic or surgical evaluation and treatment. If other markers or neurologic symptoms are present, however, radiographic evaluation may be indicated.

Buttocks↗

PubMed2000

Superficial surgical landmarks for the transverse sinus and torcular herophili.

OBJECT: The purpose of this anatomical study is to identify reliable external landmarks that can be used to determine accurately the lower border of the proximal segment of the transverse sinus (TS). METHODS: The authors used 15 formalin-fixed cadaveric specimens for this project. Various anatomical structures were dissected and measurements of the distance between these structures and the proximal TS were obtained. The data collected in this study demonstrate that the inion is not always a reliable external landmark to use when determining the internal location of the very proximal TS and its drainage into the area of the torcular herophili. In addition, the authors found that the most accurate external landmark to use in reliably estimating the internal placement of the proximal TS is the point of insertion of the musculus semispinalis capitus and not the superior nuchal line. In the present study, this muscle never covered more than 5 mm of the inferior edge of the TS and was found to be a reliable anatomical structure for avoiding the medial segment of the TS. CONCLUSIONS: These findings could aid the surgeon in localizing the TS with various midline approaches to the posterior fossa and the craniocervical junction.

Aged↗

PubMed2000

The apical ligament: anatomy and functional significance.

OBJECT: The authors conducted a study to describe the detailed anatomy of the apical ligament and to acknowledge or refute its historical description as a functionally significant contributor to craniocervical stability. METHODS: In 20 adult human cadavers measurements of the apical ligament were obtained, and its detailed anatomy was observed. Ranges of motion were also assessed to discern the function of the apical ligament. CONCLUSIONS: Results of the study support the concept that the apical ligament is best described as a vestigial structure that offers no significant added stability to the craniocervical junction. In fact, this ligament was absent in 20% of the specimens examined. These data will aid physicians who frequently view images or manage clinical problems of the craniocervical junction because they may focus on other ligaments of this area and not the apical ligament.

Adult↗

PubMed1999

Ventral brain stem compression in pediatric and young adult patients with Chiari I malformations.

OBJECTIVE: The purposes of this study were as follows: 1) to determine the incidence and degree of ventral brain stem compression (VBSC) in pediatric and young adult patients with Chiari I malformations, and 2) to correlate VBSC with other imaging and clinical factors to help determine what amount of VBSC is successfully treated with a posterior decompressive procedure alone. METHODS: The magnetic resonance images and clinical histories of 40 pediatric and young adult patients with Chiari I malformations were analyzed for subjective grade of VBSC, distance of tonsillar descent, odontoid's relation to Chamberlain's and Wackenheim's line, clival length, foramen magnum diameter, syringomyelia, scoliosis, hydrocephalus, presenting clinical status, treatment, and outcome. To objectively measure the amount of ventral cervicomedullary encroachment by the odontoid and its investing tissues into the rostral spinal canal, a line (B-C2) was drawn between the basion and posteroinferior aspect of the C2 body on a sagittal magnetic resonance image. A line perpendicular to this line, pB-C2, was drawn through the odontoid tip to the ventral dura, and a distance (representing the amount of ventral canal encroachment) was measured. RESULTS: Flattening and distortion of the ventral brain stem were present in 48 and 28% of the patients, respectively. Only two patients had basilar invagination by traditional definitions. pB-C2 measurements correlated with the subjective grade of VBSC (P < 0.05), age, and distance of tonsillar descent (P < 0.05). Eye motion abnormalities and upper cervical osseous anomalies were associated with higher pB-C2 measurements. All patients with a pB-C2 measurement of less than 9 mm were treated successfully with posterior fossa decompression alone despite any subjective VBSC. Some patients with pB-C2 measurements greater than 9 mm had either preoperative neurological deficits or neurological worsening after posterior fossa decompression referable to VBSC. CONCLUSION: Patients with a pB-C2 measurement of less than 9 mm do not require treatment directed at VBSC. In select patients with pB-C2 measurements of 9 mm or greater, reduction of VBSC may be prudent before posterior fossa decompression.

Adolescent↗

PubMed1999

Filum terminale fusion and dural sac termination: study in 27 cadavers.

The standard approach for sectioning of the filum terminale for a tethered spinal cord can be achieved via a limited S(1) exposure. This is performed with the commonly believed idea that the filum fuses with the dura at S(2). We dissected 27 cadavers to exclusively look at the level at which the filum pierces/fuses with the dura and also the level at which the dural sac ends. Most of the fila fused at S(2) with a range from L(5) to S(3). The majority of dural sacs ended at S(2) with a range from S(1) to S(3). However, 15% of the fila (4 of 27) fused above the S(1) level. In addition, 11% of the fila (3 of 27) fused off the midline. We hope that this anatomical information may be useful for neurosurgeons when standard approaches fail to identify the filum at its usual level and location.

Aged↗

PubMed1999

Effect of intrauterine myelomeningocele repair on central nervous system structure and function.

BACKGROUND: It has been postulated that intrauterine myelomeningocele repair might improve neurologic outcome in patients with myelomeningocele. A total of 59 such procedures have been performed at Vanderbilt University. Preliminary results suggested that the degree of hindbrain herniation is reduced by intrauterine repair. In an attempt to further quantify the possible benefits of this surgery, a subset of these patients was brought back to Vanderbilt for study. METHODS: A group of 26 patients who had undergone intrauterine myelomeningocele repair underwent an extensive evaluation which included manual muscle testing, MR imaging and precise determination of the anatomic level of their lesions as well as multiple other tests. The results of this analysis were compared to those in 2 groups of historical controls. RESULTS: In this group of patients intrauterine myelomeningocele repair substantially reduced the incidence of moderate to severe hindbrain herniation (4 vs. 50%). The incidence of shunt-dependent hydrocephalus was more modestly reduced (58 vs. 92%). The average level of leg function closely matched the average anatomic level of the lesion in both the fetal surgery and control groups. CONCLUSION: The most dramatic effect of intrauterine repair appears to be on hindbrain herniation. A less dramatic, but significant, reduction in shunt-dependent hydrocephalus is also seen. Prospective patients should be cautioned not to expect improvement in leg function as the result of this surgery. The potential benefits of surgery must be carefully weighed against the potential risks of prematurity.

Cerebrospinal Fluid Shunts↗

PubMed1998

Death in shunted hydrocephalic children in the 1990s.

Using a combined search of the Children's Hospital (Birmingham, Ala., USA) medical records and the Jefferson County Health Department death records, we reviewed all shunt-related deaths that occurred between January 1990 and July 1996. Of these, we excluded patients who died of nonhydrocephalus-related reasons, such as bronchopulmonary dysplasia, as well as patients who had other serious neurological illnesses such as brain tumor and hydranencephaly. Twenty-eight patients died of shunt-related causes in the 6.5-year period. A survival analysis showed that 96% survived 32 months after first shunting. Of 28 patients, 23 were beyond help prior to medical evaluation. However, at least 10 of these patients had symptoms suggestive of shunt failure at least 24 h and as long as 2 weeks prior to their demise. We conclude that hydrocephalic children still die of shunt failure despite the modern technology of the 1990s. Some of these causes may be avoidable through early detection of symptoms. Guidelines to patients, families, and primary caregivers should be emphasized.

Adolescent↗

PubMed1998

Pitfalls in the diagnosis of ventricular shunt dysfunction: radiology reports and ventricular size.

INTRODUCTION: The diagnosis of shunt malfunction can be difficult even for the experienced clinician and may lead to disastrous circumstances when misinterpreted. Less experienced physicians may rely more on radiographic reports as a primary diagnostic modality. In this study, we evaluated the reliability of using these reports without accurate clinical assessment. METHODS: All shunt revisions seen at Children's Hospital (Birmingham, AL) between January 1996 and August 1996 were reviewed, excluding patients with brain tumors, supratentorial extraaxial fluid collections, and infections. Sixty-eight patients underwent 100 operations for shunt malfunction. All patients had evidence of shunt blockage, disconnection, catheter malposition, or valve pressure incompatibility. The prospective radiographic interpretation of preoperative computed tomography and magnetic resonance imaging scans was reviewed in each case. RESULTS: Twenty-four percent of the reports made no mention of shunt malfunction. In this group, the ventricular system was described as "unchanged," "stable," "normal," "unremarkable," "small," "smaller," "slit," "negative," and "no hydrocephalus," with no other comment to support a diagnosis of shunt malfunction. An additional 9% of reports contained the same terms, while also hinting at some other clinical or radiographic data that suggest the possibility of shunt failure (e.g., a shunt disconnection seen on plain radiographs), despite the scan findings. In all patients in this group, symptoms improved after surgery. CONCLUSION: We conclude that as many as one third of patients presenting with shunt malfunction will not have the diagnosis of shunt malfunction supported by a prospective radiologic interpretation of brain imaging. Although the neurosurgical community can assess the clinical situation to determine the need for surgery, other clinicians can be easily reassured by a radiographic report that does not mention or diagnose shunt malfunction. Today, more than ever, nonneurosurgeons are being called on to evaluate complex clinical situations and may rely on radiographic reports.

Adolescent↗

PubMed1998

Congenital tethered spinal cord syndrome in adults.

OBJECT: The management of tethered spinal cord syndrome with onset of symptomatology occurring in adulthood remains controversial, although the necessity of early surgery in the pediatric tethered cord syndrome population is well established. To ascertain the results of surgery in adult patients with this anomaly, the authors undertook a retrospective review of 34 cases. METHODS: The authors studied the hospital records of 34 consecutive patients who presented in adulthood with tethered cord syndrome and conducted follow-up phone interviews with 28 of them. The population consisted of 12 men and 22 women, ranging in age from 18 to 70 years (mean 34 years). The most common presenting feature was pain, followed by weakness and incontinence. All patients underwent surgery. The most common operative findings were tight filum terminale, split cord malformation, and lipomyelomeningocele, paralleling those observed in pediatric studies. Long-term surgical results and patient outcome ratings were encouraging. After a mean clinical follow-up period of 4 years, significant improvement occurred in 22 of 27 patients presenting with pain, 13 of 27 patients with motor or sensory dysfunction, and 11 of 18 patients with bowel and bladder disturbance. In addition, telephone interviews were obtained after a period of 8.6 years. Twenty-two (79%) of 28 patients called the operation a long-term success; 21 (75%) of 28 patients believed that they had significant postoperative improvement (and not just stabilization) in pain and/or neurological function. Surgical complications were generally minor. Nineteen (86%) of 22 employed patients returned to work after surgery. Two (33%) of six patients who were not employed before surgery worked full time postoperatively. Only two of the 28 patients interviewed had received Workers' Compensation benefits; both of these had good outcomes and returned to work. CONCLUSIONS: Tethered spinal cord syndrome in adults is an uncommon entity that can become symptomatic. Although surgery in adults involves greater risk of neurological injury than in children, it is a low-risk procedure with encouraging results. Because neurological deficits are generally irreversible, early surgery is recommended.

Adolescent↗

PubMed1998

The resolution of syringohydromyelia without hindbrain herniation after posterior fossa decompression.

OBJECT: To provide more information about this rare condition, the authors describe five cases of syringohydromyelia without hindbrain herniation. Preoperative magnetic resonance imaging with and without gadolinium-diethylenetriamine pentaacetic acid revealed no evidence of spinal cord tumor, arachnoiditis, or spinal dysraphism. METHODS: Craniocervical decompression was performed in all patients, after which there was resolution of the symptoms in the four symptomatic patients, and all five showed marked reduction in the size of the syrinx. CONCLUSIONS: The authors hypothesize the rare occurrence of syringohydromyelia resulting from a Chiari-like pathophysiological condition but lacking a hindbrain hernia. Patients with this condition may benefit from craniocervical decompression.

Adolescent↗