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A T Casey

Publications and source records attributed to A T Casey.

At least 37 records · Page 2Linked to original sources
PubMed1997

Variation of the groove in the axis vertebra for the vertebral artery. Implications for instrumentation.

Transarticular screws at the C1 to C2 level of the cervical spine provide rigid fixation, but there is a danger of injury to a vertebral artery. The risk is related to the technical skill of the surgeon and to variations in local anatomy. We studied the grooves for the vertebral artery in 50 dry specimens of the second cervical vertebra (C2). They were often asymmetrical, and in 11 specimens one of the grooves was deep enough to reduce the internal height of the lateral mass at the point of fixation to < or =2.1 mm, and the width of the pedicle on the inferior surface of C2 to < or =2 mm. In such specimens, the placement of a transarticular screw would put the vertebral artery at extreme risk, and there is not enough bone to allow adequate fixation. Before any decision is made concerning the type of fixation to be used at C2 we recommend that a thin CT section be made at the appropriate angle to show both the depth and any asymmetry of the grooves for the vertebral artery.

Anthropometry↗
PubMed1997

Medulloblastoma: is the 5-year survival rate improving? A review of 80 cases from a single institution.

A series of 80 cases of medulloblastomas in children undergoing operation and postoperatively followed between 1980 and 1990 at Great Ormond Street Hospital for Children (GOSH) has been reviewed and compared to an earlier series reported from the same institution by McIntosh. The overall 5-year survival rate for the present series was 50%, although three patients died after surviving 5 years. The operative mortality rate was 5%. Survival analysis revealed that the presence or absence of spinal metastases and the necessity for some form of cerebrospinal fluid diversion within 30 days of the operation independently significantly affected survival in this series. Those patients with no spinal metastasis and total tumor removal had a 5-year survival rate of 73%, making this the most favorable subgroup in the series. Patient age and gender, duration of symptoms, Chang T stages, tumor volume, extent of resection, and postoperative chemotherapy were not significant variables. Although these results are better than those reported in the earlier GOSH series, they are not significantly different from the results of the second 5-year cohort of patients described in that article. Radiotherapy remains the greatest advance in treatment, although it is hoped that further improvement will result from the various chemotherapy protocols now being studied and from increasing knowledge of the biological behavior of these tumors.

Adolescent↗
PubMed1997

Radiological and anatomical evaluation of the atlantoaxial transarticular screw fixation technique.

Sixty-one patients treated with C1-2 transarticular screw fixation for spinal instability participated in a detailed clinical and radiological study to determine outcome and clarify potential hazards. The most common condition was rheumatoid arthritis (37 patients) followed by traumatic instability (15 patients). Twenty-one of these patients (one-third) underwent either surgical revision for a previously failed posterior fusion technique or a combined anteroposterior procedure. Eleven patients underwent transoral odontoidectomy and excision of the arch of C-1 prior to posterior surgery. No patient died, but there were five vertebral artery (VA) injuries and one temporary cranial nerve palsy. Screw malposition (14% of placements) was comparable to another large series reported by Grob, et al. There were five broken screws, and all were associated with incorrect placement. Anatomical measurements were made on 25 axis bones. In 20% the VA groove on one side was large enough to reduce the width of the C-2 pedicle, thus preventing the safe passage of a 3.5-mm diameter screw. In addition to the obvious dangers in patients with damaged or deficient atlantoaxial lateral mass, the following risk factors were identified in this series: 1) incomplete reduction prior to screw placement, accounting for two-thirds of screw complications and all five VA injuries; 2) previous transoral surgery with removal of the anterior tubercle or the arch of the atlas, thus obliterating an important fluoroscopic landmark; and 3) failure to appreciate the size of the VA in the axis pedicle and lateral mass. A low trajectory with screw placement below the atlas tubercle was found in patients with VA laceration. The technique that was associated with an 87% fusion rate requires detailed computerized tomography scanning prior to surgery, very careful attention to local anatomy, and nearly complete atlantoaxial reduction during surgery.

Adolescent↗
PubMed1997

Vertical translocation: the enigma of the disappearing atlantodens interval in patients with myelopathy and rheumatoid arthritis. Part I. Clinical, radiological, and neuropathological features.

This statistical comparison between patients with cervical myelopathy secondary to horizontal atlantoaxial subluxation and those with vertical translocation is designed to elucidate the mechanisms responsible for cranial settling and the effect of translocation on the development of spinal cord compression. In a 10-year study of a cohort of 256 patients, 186 suffered from myelopathy and 116 (62%) of these exhibited vertical translocation according to the Redlund-Johnell criteria. Vertical translocation occurred after a significantly longer period of disease than atlantoaxial subluxation (p < 0.001). Translocation was characterized clinically by a high cervical myelopathy with features of a cruciate paralysis present in 35% of individuals compared with 26% who exhibited horizontal atlantoaxial subluxation (p = 0.29), but there was a surprising paucity of cranial nerve problems. The patients with vertical translocation had a greater degree of neurological disability (p = 0.002) and poorer survival rates (p = 0.04). Radiologically, vertical translocation was secondary to lateral mass collapse and associated with a progressive decrease in the atlantodens interval ([ADI], r = 0.4; p < 0.001) and pannus (p = 0.003). Thirty percent of patients exhibited an ADI of less than 5 mm. This phenomenon has been termed pseudostabilization. The authors' studies emphasize that the ADI (frequently featured in the literature) is totally unreliable as an indicator of neuraxial compromise in the presence of vertical translocation.

Arthritis, Rheumatoid↗
PubMed1997

Vertical translocation. Part II. Outcomes after surgical treatment of rheumatoid cervical myelopathy.

This is a prospective observational study in 116 patients with rheumatoid arthritis and vertical translocation who underwent cervical spine surgery after developing symptomatic myelopathy. These patients, whose mean age was 62 years, had suffered from rheumatoid arthritis for almost 25 years. Surgery was performed via a combination of anterior (67 transoral decompressions) and posterior approaches. Surgical morbidity was recorded in 39% of patients, with a 30-day mortality rate of 10.3%, which was largely related to poor preoperative neurological grade. Neurological improvement of at least one Ranawat class was observed in 55 patients. Univariate analysis revealed the following clinical variables to be associated with a good neurological outcome (Ranawat class): younger age and good preoperative muscle power. Significant radiological variables included the degree of vertical translocation as measured by the Redlund-Johnell method and the preoperative spinal cord area. The degree of transgression in the foramen magnum did not significantly affect neurological outcome. Neither the anterior nor the posterior atlantodens interval predicted neurological recovery. Multiple logistic regression models were constructed based on the preliminary evidence of the authors' univariate analysis and these confirmed the importance of preoperative neurological function, spinal cord area, and the degree of vertical translocation in influencing the final neurological grade.

Age Factors↗
PubMed1996

Surgery on the rheumatoid cervical spine for the non-ambulant myelopathic patient-too much, too late?

BACKGROUND: Opinions differ on the timing of surgery for rheumatoid arthritis patients with atlanto-axial subluxation. Some clinicians wait for development of neurological signs; others favour prophylactic fusion and decompression. We examined the results of surgery in relation to neurological state at the time of operation. METHODS: 134 patients underwent surgery for rheumatoid involvement of the cervical spine, after development of objective signs of myelopathy. Surgical outcomes were examined prospectively in two groups-patients who were still ambulant at the time of presentation (Ranawat class III A) and patients who had lost the ability to walk (Ranawat class III B)-by means of neurological and functional grading systems in conjunction with standard measures of postoperative morbidity and mortality. FINDINGS: 58% of the ambulant patients attained Ranawat neurological grades I or II compared with only 20% of the non-ambulant patients (p<0.0001). The non-ambulant group also fared worse in terms of postoperative complication rate, length of hospital stay, functional outcome, and ultimately survival. Radiologically, the non-ambulant patients were characterised by a smaller cross-sectional spinal cord area. INTERPRETATION: The strong likelihood of surgical complications, the poor survival, and the limited prospects for functional recovery in non-ambulant patients make a strong case for earlier surgical intervention. At a late stage of disease most patients will have irreversible cord damage.

Adult↗
PubMed1996

A novel technique for laminoplasty augmentation of spinal canal area using titanium miniplate stabilization. A computerized morphometric analysis.

STUDY DESIGN: Titanium miniplates are used to secure the posterior elements in the open position after expansive open-door laminoplasty. Preoperative and postoperative spinal canal dimensions are measured to assess the effectiveness of this technique. OBJECTIVES: To develop a simple yet effective technique to stabilize the posterior elements after laminoplasty and to compare preoperative and postoperative spinal canal dimensions to accepted normal values. SUMMARY OF BACKGROUND DATA: Expansive open-door laminoplasty has been offered as a simple alternative to laminectomy, which has been associated with postoperative kyphosis. Although the technique of laminoplasty is effective, a simple and reliable method of holding the posterior elements open has not been described. METHODS: Ten myelopathic patients with multilevel cervical canal stenosis secondary to spondylosis or ossification of the posterior longitudinal ligament were treated with an expansive open-door laminoplasty. The posterior elements were stabilized in the open position with titanium miniplates. Computer-assisted morphometric analysis was performed on preoperative and postoperative computed tomography scans to obtain spinal canal dimensions. Plain radiographs were used to monitor construct integrity. RESULTS: The preoperative sagittal canal diameter was 8.2 +/- 0.96 mm, and the canal area was 180.6 +/- 33.7 mm2. These dimensions increased after surgery to 16.6 +/- 1.5 mm and 321.9 +/- 29.7 mm2, respectively. The titanium miniplate constructs did not fail during the follow-up period (mean, 26.4 months), and the decompression was maintained. The single significant complication was transient C5 radiculopathy. CONCLUSIONS: Normal canal dimensions can be reestablished with open-door laminoplasty. Achieving and maintaining an increased sagittal canal diameter is probably the most important change in anatomic parameters to facilitate neurologic recovery. The use of titanium miniplates to stabilize the posterior elements after laminoplasty is a simple, durable, and effective technique to maintain the increased sagittal diameter of the spinal canal.

Adult↗
PubMed1996

Does the child with shunted hydrocephalus require long-term neurosurgical follow-up?

A prospective study was initiated to investigate parents' and doctors' attitudes towards how the follow-up of children treated with shunts for hydrocephalus should be undertaken. Twenty-three out of 85 (27%) of families whose children had been treated more than 6 months previously failed to attend for their clinic appointment compared with 15% of those attending for other (non-hydrocephalus-related) problems. The possible reasons for this discrepancy have been analysed together with the results of a questionnaire filled in by both the parents and the clinic doctors at the time of the appointment. Although both parties felt that there was a sizeable group of patients for whom continuing neurosurgical follow-up was no longer required there was little concordance in identifying who these patients actually were. Also taken into account were the economic factors which influence both parental and medical decision-making. In the light of our study, new ways of managing the follow-up of these children have been formulated.

Adolescent↗
PubMed1996

Development of a functional scoring system for rheumatoid arthritis patients with cervical myelopathy.

OBJECTIVE: To be able to measure disability objectively in rheumatoid arthritis complicated by cervical myelopathy. METHODS: The responses to the Stanford health assessment questionnaire disability index were recorded from 250 consecutive patients (group 1) referred to our unit for spinal surgery. Using principal components analysis the questionnaire was reduced from 20 questions to 10 questions. In the second part of the study, the results of the questionnaire for those patients undergoing surgery from the original group of 250 patients were analysed with respect to outcome. RESULTS: The reduction in the number of questions results in no significant loss of information, reliability (internal consistency Cronbach's alpha = 0.968) or sensitivity. The new scale, the myelopathy disability index, measures only one dimension (Eigen value 6.97) and may be more finely tuned to the measurement of disability in these myelopathic patients. When administered to the 194 patients undergoing cervical spine (group 2) surgery the myelopathy disability index was an accurate predictor of neurological and functional outcome, as well as survival following surgery (P < 0.0001). CONCLUSIONS: The myelopathy disability index provides a much needed objective and reliable means of assessing disability in patients with rheumatoid involvement of the cervical spine and also in predicting outcome following surgical intervention. It also provides information for both the patient and surgeon alike, on what to realistically expect from surgery. Its adoption should facilitate comparisons between different forms of surgical intervention.

Activities of Daily Living↗
PubMed1996

Predictors of outcome in the quadriparetic nonambulatory myelopathic patient with rheumatoid arthritis: a prospective study of 55 surgically treated Ranawat class IIIb patients.

The functional results of surgery in patients with myelopathic nonambulatory rheumatoid arthritis (Ranawat Class IIIb) are often disappointing, with high rates of postoperative morbidity and mortality. The authors therefore undertook a detailed investigation of a cohort of 55 Ranawat Class IIIb patients (11 men and 44 women) with a mean age of 64.7 years who were recruited prospectively over a 10-year period (1983-1993), to determine what factors may accurately predict a good surgical outcome. Only 14 patients (25.5%) were judged to have had a favorable outcome as determined by an improvement to Ranawat Class I or II or an improvement of at least 0.5 points in the Stanford Health Assessment Questionnaire disability index. The early postoperative mortality rate was high (12.7%) in this group and almost one-quarter of the patients were dead within 6 months. These poor results mirror those already published in the existing literature. Univariate analysis revealed that age (p = 0.02), degree of vertical translocation (p = 0.05), and, more importantly, spinal cord area (p = 0.006) were significant predictors of outcome. Multiple logistic regression analysis showed that spinal cord area (p = 0.026) was, in fact, the major determinant of outcome and, indeed, of long-term survival (p = 0.001). The mean spinal cord area of those patients not achieving a good outcome was 44 mm2. The atlantodens interval (ADI) was not shown to be a significant outcome determinant, which may be explained by the correlation between an increasing vertical translocation and a decreasing ADI (r = 0.4, p = 0.01). Furthermore, as the degree of vertical translocation increased, the space available for the cord was observed to decrease (p = 0.003) commensurate with a reduction in spinal cord area (p = 0.02). Together, these findings strongly argue for earlier surgical intervention, before the development of vertical translocation, permanent neurological damage, and spinal cord atrophy can occur.

Adult↗
PubMed1996

Use of intracranial pressure monitoring in the management of childhood hydrocephalus and shunt-related problems.

Although the clinical and radiological diagnosis of hydrocephalus in children is usually straightforward, there exists a minority of patients in whom the decision to shunt can be extremely difficult. Similarly, although the diagnosis of shunt malfunction usually presents little difficulty in the context of an acute blockage, a child can present with a confusing and unpredictable constellation of symptoms that might be caused by conditions separate from shunt malfunction. Continuous intraparenchymal intracranial pressure (ICP) monitoring was used to assess 41 patients with hydrocephalus, either as part of the initial diagnostic evaluation of ventriculomegaly (18 patients) or in the assessment of presumed shunt malfunction (23 patients). In 9 of 18 patients with ventriculomegaly, the ICP was within normal limits and surgical insertion of shunts was avoided. Of the 23 patients being assessed for shunt malfunction, the change in ICP profile indicated a siphoning or overdrainage process in 13. In no patient was there significant attendant morbidity, and the process was well tolerated and simple to perform. Clinical and radiological criteria alone can afford insufficient information in the initial evaluation and the subsequent management of the child with hydrocephalus. ICP monitoring provides a safe means of investigating such patients and provides valuable information upon which to base surgical management.

Adolescent↗
PubMed1995

The use of autologous skull bone grafts for posterior fusion of the upper cervical spine in children.

STUDY DESIGN: Traditionally bone grafts used in posterior cervical fusion have been harvested from the iliac crest, rib, tibia, or fibula. Their use is not without significant morbidity, and it is often difficult to harvest suitable quantities of good quality bone in children. We have used autologous calvarial bone secured by sublaminar wires in seven patients with congenital spinal anomalies to achieve craniocervical stabilization and fusion. OBJECTIVES: To detail our experiences with this new method of harvesting autologous bone grafts from the patient's skull for occipitocervical fusion in a pediatric practice. SUMMARY OF BACKGROUND DATA: Calvarial bone has been used extensively in craniofacial reconstructive work with good long-term results and with no significant bone resorption. The use of membranous bone is supported by several basic science studies reported in the plastic surgery literature that claim a superiority over endochondral bone regarding fusion. In the present study, autologous calvarial bone has been used in the treatment of seven cases of congenital upper cervical spine instability associated with neurologic deficit. This method circumvents many of the problems attached to the use of traditional donor sites and provides good quality bone in large quantity that can be specifically tailored to match the contours of the craniocervical junction. METHOD: We used autologous calvarial bone secured by sublaminar wires in seven children with congenital spinal anomalies to achieve craniocervical stabilization and fusion. The ensuing calvarial defect was repaired using split-thickness parietal bone with the bone graft, which was ultimately used for the cervical fusion and acted as a template to obtain a mirror image and exact match to achieve good cosmetic results. The patients were immobilized after surgery in a halo orthosis for 3 months. RESULTS: Satisfactory results (100% fusion) were achieved in all seven cases with no attendant morbidity related to the method of graft procurement. CONCLUSIONS: We recommend this technique as a safe and effective alternative to the more traditional means of graft procurement previously used in cases of craniocervical instability in children.

Adolescent↗
PubMed1995

Stereotactically-guided craniotomy for cavernous angiomas presenting wit epilepsy.

With the wider availability of magnetic resonance imaging cavernous malformations are being recognised with increasing frequency in those patients presenting with intractable epilepsy. Surgical resection is the treatment of choice. However, because these lesions are usually small and may be located in eloquent areas stereotactic resection should be considered. Stereotactically-guided resection of pathologically verified cavernous angiograms was performed in 10 patients in this series presenting with epilepsy (8 males, 2 females, mean age 32 years). Eight patients presented with medically intractable epilepsy (5 complex partial seizures, 3 grand mal seizures). Of the remaining patients one experienced multiple episodes of haemorrhage and the other headaches (with a non-diagnostic scan) both in association with epilepsy. Pre-operative localisation of the motor strip was determined in one case by functional MRI. Following resection of these lesions all patients experienced improved seizure control with a mean follow-up period of 22 months. The mean postoperative hospital stay was 5.1 days with no surgical complications recorded. We conclude that stereotactically-guided resection offers significant advantages in the management of cavernous malformations. Surgical indications for operative resection would include medically refractory epilepsy, repeated haemorrhage and those cases where there is diagnostic uncertainty.

Adolescent↗
PubMed1995

Accurate placement of the atrial catheter in ventriculoatrial shunts. Technical note.

A combined radiological and surgical technique that permits identification of appropriate recipient vessels and accurate placement of the atrial catheter in ventriculoatrial shunts is described. The procedure uses readily available radiological skills and reduces operation time and morbidity related to malpositioning of the distal catheter.

Catheterization↗
PubMed1994

Aspergillosis infection in neurosurgical practice.

Fungal infections including those due to aspergillus are rare in neurosurgical practice despite their possible inclusion in many differential diagnoses. Recently, these diseases have been diagnosed with increasing frequency, principally as opportunistic infections in patients undergoing treatment for diseases resulting in immune compromise. The epidemiology is poorly understood as mycoses are not notifiable diseases. We have recently been involved in the care of seven patients with aspergillosis between 1988 and 1991. Its presentation, with abscess formation, granulomas, the rhinocerebral form, meningitis, hydrocephalus and vascular involvement, is varied. The majority of cases were seen in immunocompromised patients following haematogenous dissemination from a pulmonary or gastro-intestinal focus. Direct spread from sinus infection has also been seen. The prognosis is poor despite modern antifungal treatment, which in part reflects the primary underlying condition.

Adult↗
PubMed1994

A traumatic giant posterior cerebral artery aneurysm mimicking a tentorial edge meningioma.

Traumatic intracranial aneurysms due to non-penetrating trauma are rare. Commonly they are associated with an overlying fracture or secondary to trauma against the falcine edge in the case of the distal anterior cerebral artery. To date, only one case of traumatic posterior cerebral artery aneurysm has been reported associated with a comminuted depressed occipital fracture and lacerated transverse sinus. We report a case of a giant traumatic aneurysm of the posterior cerebral artery P2 branch directly associated with the tentorial edge. Its mechanism of formation is analogous to the falcine distal anterior cerebral artery aneurysms.

Adult↗