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Biomedical subjects

A H Menezes

Publications and source records attributed to A H Menezes.

At least 19 recordsLinked to original sources
PubMed1998

Occipital calvarial bone graft in posterior occipitocervical fusion.

STUDY DESIGN: Dorsal occipitocervical fusion is associated with a high rate of fusion failure and requires an additional surgical site for donor bone graft harvesting. In this series, an autologous occipital calvarial bone graft obtained from the same occipitocervical incision with contoured metal loops was used in 25 adults to achieve craniovertebral stabilization and fusion. OBJECTIVES: To study the use of autologous occipital calvarial bone grafts in occipitocervical fusion. SUMMARY OF BACKGROUND DATA: Cranial bone grafts have been used successfully in craniofacial reconstruction with good long-term results. In the plastic surgery literature, there are claims that membranous bone grafts are superior to endochondral bone grafts in fusions because of decreased resorption. In recent studies, results have shown successful use of calvarial bone in fusing the upper cervical spine in children. The use of autologous occipital bone in posterior occipitocervical fusions avoids many of the problems associated with traditional donor sites and provides a sufficient quantity of good quality bone for the fusion. This is especially true in the fragile rheumatoid arthritis patient with cranial cervical instability. METHOD: Split-thickness, autologous calvarial bone grafts with contoured loop and cable instrumentation were used for posterior occipitocervical stabilization and fusion in 25 patients, most of whom had rheumatoid arthritis. The calvarial bone graft was harvested from the occipital skull, using a microair impactor, and was secured next to the loop construct. After surgery, all patients were immobilized with external orthoses. RESULTS: None of the patients had hardware failure or complications from the occipital graft procurement. In 22 patients, good alignment, stability, and bony fusion were shown on radiographs. CONCLUSIONS: Occipital calvarial bone graft appears to work as well as other autologous corticocancellous bone grafts routinely used in posterior occipitocervical fusions.

Adolescent↗
PubMed1998

Presentation, management and follow-up of Schilder's disease.

Schilder's diffuse myelinoclastic sclerosis is a rare demyelinating disease which often mimics intracranial neoplasm or abscess. We have treated 3 patients with this disorder in the past 5 years and followed their postoperative course. Certain distinct features of this disease will allow neurosurgeons to preoperatively entertain this diagnosis. We discuss postoperative treatment and propose a new hypothesis regarding the variable prognoses of this disorder. Schilder's disease constitutes an important diagnosis for any neurosurgeon to be aware of (especially those treating the pediatric age group) which has not received adequate coverage in the neurosurgical literature.

Adolescent↗
PubMed1998

A comparative analysis of fusion rates and donor-site morbidity for autogeneic rib and iliac crest bone grafts in posterior cervical fusions.

OBJECT: Autogeneic bone graft is often incorporated into posterior cervical stabilization constructs as a fusion substrate. Iliac crest is used frequently, although donor-site morbidity can be substantial. Rib is used rarely, despite its accessibility, expandability, unique curvature, and high bone morphogenetic protein content. The authors present a comparative analysis of autogeneic rib and iliac crest bone grafts, with emphasis on fusion rate and donor-site morbidity. METHODS: A review was conducted of records and radiographs from 600 patients who underwent cervical spinal fusion procedures in which autogeneic bone grafts were used. Three hundred patients underwent rib harvest and posterior cervical fusion. The remaining 300 patients underwent iliac crest harvest (248 for an anterior cervical fusion and 52 for posterior fusion). The analysis of fusion focused on the latter subgroup; donor-site morbidity was determined by evaluating the entire group. Fusion criteria included bony trabeculae traversing the donor-recipient interface and long-term stability on flexion-extension radiographs. Graft morbidity was defined as any untoward event attributable to the graft harvest. Statistical comparisons were facilitated by using Fisher's exact test. CONCLUSIONS: Demographic data obtained in both groups were comparable. Rib constructs were placed in the following regions: occipitocervical (196 patients), atlantoaxial (35 patients), and subaxial cervical spine (69 patients). Iliac crest grafts were placed in the occipitocervical (28 patients), atlantoaxial (10 patients), and subaxial cervical (14 patients) regions. Fusion occurred in 296 (98.8%) of 300 rib graft and 49 (94.2%) of 52 iliac crest graft constructs (p = 0.056). Graft morbidity was greater with iliac crest than with rib (p < 0.00001). Donor-site morbidity for the rib graft was 3.7% and included pneumonia (eight patients), persistent atelectasis (two patients), and superficial wound dehiscence (one patient). Pneumothorax, intercostal neuralgia, and chronic chest wall pain were not encountered. Iliac crest morbidity occurred in 25.3% of the patients and consisted of chronic donor-site pain (52 patients), wound dehiscence (eight patients), pneumonia (seven patients), meralgia paresthetica (four patients), hematoma requiring evacuation (three patients), and iliac spine fracture (two patients). Even when chronic pain was not considered, morbidity encountered in obtaining iliac crest still exceeded that encountered with rib harvest (p = 0.035). The fusion rate and donor-site morbidity for rib autograft compare favorably with those for iliac crest when used in posterior cervical constructs. To the authors' knowledge, this represents the largest series to date in which the safety and efficacy of using autogeneic bone graft materials in spinal surgery are critically analyzed.

Adult↗
PubMed1997

Primary tumors of the spine in children. Natural history, management, and long-term follow-up.

STUDY DESIGN: Patients 16 years of age and younger with primary vertebral neoplasms diagnosed between 1951 and 1996 at The University of Iowa were reviewed retrospectively with specific consideration given to follow-up. OBJECTIVE: Follow-up extending beyond the growth of the axial skeleton was used to establish the natural history, management outcome, and current approach to treatment. SUMMARY OF BACKGROUND DATA: Primary tumors of the spine are uncommon. The treatment of such lesions generally has been based on small series of tumors, or extrapolated from the treatment of tumors in other regions and tumors in adults. Given the unique developing anatomy and dynamic nature of the growing spine in children, delineating appropriate modalities of treatment for these tumors beyond the growth of the axial skeleton is essential. METHODS: Clinical history, radiographs, radiographic reports, and interviews were used to establish this database. Outcome with respect to the various approaches to treatment was then compared in detail. RESULTS: Forty-five patients were identified in which follow-up greater than 10 years was available for 58% of patients. There were 29 histologically benign and 16 malignant tumors. Patients presented most frequently with pain (79%) and neurologic deficits (74%). The duration of symptoms was significantly shorter with malignant tumors (11 weeks) compared with benign tumors (26 weeks). Radiographic abnormalities were demonstrated on plain radiographs in 98% of cases. Tumor excision was achieved in 80%. Follow-up studies were available beyond the growth of the axial skeleton in these patients, with an average follow-up of 14 years. Recurrence was seen in 6 of 45 children, and the overall mortality rate was 6.7%, occurring only with malignant tumors. CONCLUSION: Our current approach to treatment of spinal neoplasms varies from that used in the earlier part of the series and reflects the need for single stage complete resection and stabilization.

Adolescent↗
PubMed1997

Craniovertebral junction anomalies: diagnosis and management.

The craniovertebral junction is the most complex of the axial skeleton, residing between the skull and the upper cervical spine. Congenital, developmental, and acquired bony abnormalities result in compression and distortion of the neural structures, the vertebrobasilar vascular system, and the cerebrospinal fluid channels. The clinical significance of this has only been recently recognized, and mistaken diagnoses have led to a delayed treatment and at times adverse results. A review of the anatomy, the embryology, and the mechanics of this region is essential to the understanding of the pathophysiology encountered.

Atlanto-Axial Joint↗
PubMed1997

Neuromuscular scoliosis: diagnostic and therapeutic considerations.

Neuromuscular scoliosis in a child presents as a diagnostic and therapeutic dilemma to the pediatric neurologist, the pediatric neurological surgeon, and the pediatric orthopaedist. Because of its progressive nature, it tends to be refractory to conservative management and requires active intervention. Neuromuscular scoliosis is a symptom, and the diseases leading to the deformity must be addressed together with the spinal abnormality. The framework of the diagnosis and management is addressed in this article.

Case Management↗
PubMed1997

Hemorrhagic complications in association with silastic dural substitute: pediatric and adult case reports with a review of the literature.

OBJECTIVE AND IMPORTANCE: Delayed intracranial hemorrhage is an unusual complication associated with the use of silastic dural substitute. CLINICAL PRESENTATION: We present three patients with this complication. Two adult patients developed subdural and epidural hemorrhages 9 months and 10 years after posterior fossa surgery for Chiari malformations. The remaining patient, a 13-month-old child, is the youngest reported patient to develop an epidural hematoma 8 months after a craniosynostosis repair. INTERVENTION: The hematomas were removed with the silastic dural substitute from all three patients, and the dural defect was repaired with autologous paracervical fascia. CONCLUSION: Silastic dural grafts have an increased incidence of hemorrhage associated with their use. A slight increase in the prevalence of hemorrhagic complications with silastic dural substitute was observed in women. We report our radiographic and surgical findings, including an extensive review of the literature.

Adult↗
PubMed1997

Idiopathic spinal epidural lipomatosis.

OBJECTIVE: Spinal epidural lipomatosis (SEDL) is a rare disorder often associated with the administration of exogenous steroids or the elevation of endogenous steroids. Spinal epidural lipomatosis develops in some patients in the absence of elevated steroid levels. The limited information known about idiopathic SEDL comes predominantly from isolated case reports. We proposed to study our experience with idiopathic SEDL and to review the literature. METHODS: We identified eight symptomatic patients with idiopathic SEDL treated at our institution, which is the largest series reported. All patients were male and obese by body mass index (> 27.5 kg/m2). The mean age of the patients was 35.4 years. Idiopathic SEDL was equally distributed between the thoracic and lumbar spine. Six patients underwent laminectomy and fat debulking with good postoperative results; two patients were treated with a weight loss diet, which resulted in the relief of symptoms after losing > 15 kg each. RESULTS AND CONCLUSION: A review of our patients in conjunction with other reported cases reveals the following: 1) idiopathic SEDL occurs almost exclusively in the obese population; 2) idiopathic SEDL seems to occur with equal frequency between the thoracic and lumber spine; 3) a strong male predominance exists; 4) thoracic SEDL presents at an earlier age compared with lumbar SEDL; 5) surgical decompression remains the treatment of choice for the immediate relief of symptoms. Our experience suggests that idiopathic epidural lipomatosis may be a pathological entity that has been underdiagnosed.

Adolescent↗
PubMed1997

Increased height in patients with medulloblastomas.

OBJECTIVE: Medulloblastomas demonstrate histological features similar to neuroendocrine tumors. Expression of various receptors for growth factors and production of growth hormones have been identified to occur with medulloblastomas. We studied the preoperative height of patients with medulloblastomas. METHODS: We studied 85 patients (64 children and 21 adults) with medulloblastomas and 42 patients (27 children and 15 adults) with cerebellar astrocytomas who served as a control group. All of the patients had their height and weight documented on standardized growth charts. In addition, age, sex, symptoms, radiographic findings, treatment, and survival were examined. RESULTS: Preoperatively, 22.4% of the patients with medulloblastomas were above the 95% curve in height and 80.0% were above the 50% curve for height. Compared with patients with cerebellar astrocytomas, 7.1% were above the 95% curve for height and 54.8% were above the 50% curve for height. The distribution of patients along the weight curves for both tumor types demonstrated a slight prevalence for lower weights but was not significantly different from the national average. A significant number of patients presenting with medulloblastomas attained increased height, which was disproportionate to the weight loss generally observed with neoplasms. To our knowledge, the disproportionate number of patients with medulloblastomas and increased height has not been reported before. A similar deviation in height distribution from the normal population could not be identified in patients with cerebellar astrocytomas. CONCLUSION: This study suggests that medulloblastomas may be influenced by growth hormone production or may produce growth factors in vivo.

Adolescent↗
PubMed1997

Basilar invagination in osteogenesis imperfecta and related osteochondrodysplasias: medical and surgical management.

Osteogenesis imperfecta (OI) is a heritable disorder of bone development caused by defective collagen synthesis. Basilar invagination is an uncommon but devastating complication of this disease. The authors present a comprehensive strategy for management of craniovertebral anomalies associated with OI and related osteochondrodysplasias. Twenty-five patients with congenital osteochondrodysplasias (18 OI, four Hajdu-Cheney syndrome, and three spondyloepiphyseal dysplasia) and basilar invagination were evaluated between 1985 and 1995. The male/female ratio in this cohort was 1:1. The mean age at presentation was 11.9 years (range 13 months-20 years). Fourteen patients (56%) presented during adolescence (11-15 years of age). Symptoms and signs included headache (76%), lower cranial nerve dysfunction (68%), hyperreflexia (56%), quadriparesis (48%), ataxia (32%), nystagmus (28%), and scoliosis (20%). Four patients (16%) were asymptomatic. Seven (28%) had undergone previous posterior fossa decompression; one had also undergone ventral decompression. Imaging findings included basilar invagination (100%), ventral brainstem compression (84%), hydrocephalus (32%), hindbrain herniation (28%), and syringomyelia/syringobulbia (16%). Patients with hydrocephalus underwent ventricular shunt placement. Reducible basilar invagination (40%) was treated with posterior fossa decompression and occipitocervical fusion. Those with irreducible ventral compression (60%) underwent transoral-transpalatopharyngeal decompression followed by occipitocervical fusion. All patients improved initially. However, basilar invagination progressed radiographically in 80% (symptomatic in 24%) despite successful fusion. Prolonged external orthotic immobilization with the modified Minerva brace afforded symptomatic improvement and arrested progression of the deformity. The mean follow-up period was 5.9 years (range 1.1-10.5 years). Ventral brainstem compression in OI should be treated with ventral decompression, followed by occipitocervical fusion with contoured loop instrumentation to prevent further squamooccipital infolding. Despite fusion, however, basilar invagination tends to progress. Prolonged immobilization (particularly during adolescence) may stabilize symptoms and halt further invagination. This study represents the largest series to date addressing craniovertebral anomalies in OI and related congenital bone softening disorders.

Adolescent↗
PubMed1996

Sudden attacks of head pain in a young child.

In the evaluation of headaches at any age, the clinical features of the episodes are the most important diagnostic information available. In the patient presented, the nature of the headaches suggests the need for further study as well as the most fruitful location in which to look.

Cerebellum↗
PubMed1996

Management strategies for tumors of the axis vertebra.

Primary and metastatic tumors of the axis vertebra pose difficult surgical problems. The authors report 14 cases of patients with axis tumors who underwent surgery between 1970 and 1993. The eight male and six female patients ranged in age from 9 to 70 years (mean 46 years). Presenting symptoms and signs included pain in 12, myelopathy in nine, radiculopathy in four, and cranial nerve deficits in two patients. Preoperative instability of the cervical spine was present in eight patients. The goal of surgery was to achieve diagnosis, decompression, and stabilization; the choice of operative intervention was based on tumor location and patient prognosis. Six transoral-transpalatal resections, two lateral extrapharyngeal approaches, four posterolateral decompressions, and 11 dorsal decompressions were performed. Eleven fusion procedures were required to achieve spinal stability. Patients with aggressive tumors requiring concomitant radiotherapy underwent fusion using contoured loop instrumentation or methyl methacrylate, whereas those with benign lesions underwent fusion using traditional techniques. With maximum medical and surgical intervention, 10 patients are alive and their tumors are in remission. In eight of these 10 patients, gross-total resection was achieved. Four patients died from tumor progression, and in three of these cases gross-total resection was not possible. There were no operative deaths and morbidity was minimal. Development of new surgical approaches to the axis has allowed resection of previously inoperable tumors. The extent of resection correlated with the duration of survival. A classification system for axis tumors is proposed to facilitate selection of appropriate surgical approaches that will maximize the extent of resection while achieving or maintaining spinal stability.

Adolescent↗
PubMed1996

Quantitative analysis of cerebrospinal fluid spaces in children with occipital plagiocephaly.

The etiology of occipital plagiocephaly (OP) is not fully understood. The authors have observed that many infants with this condition have external hydrocephalus. This study was undertaken to quantify cerebrospinal fluid (CSF) space caliber in children with OP and to compare these measurements to those derived from normal age-matched controls to further elucidate the pathogenesis of this condition. Thirty-one infants with isolated unilateral OP (mean age 6 months) were studied. Infants with multiple cranial suture abnormalities, impaired neurological function, developmental delay, and associated craniofacial anomalies were excluded. Twenty normal infants were evaluated as controls. The volumes of the sylvian fissures, frontal and occipital subarachnoid spaces, as well as the cross-sectional areas of the suprasellar and perimesencephalic cisterns, were calculated from computerized tomography (CT) studies. Ventricular size was also assessed. Generalized subarachnoid space dilation was observed in 29 (93.5%) of the 31 children with OP. Head circumference was significantly greater in the case group (71.4 vs. 50.8 percentile; p = 0.0002 by analysis of variance). The sylvian fissure volume was significantly larger in the case group (5.8 ml vs. 0.7 ml in controls, p < 0.0001). The volume of the contralateral sylvian fissure was greater than that ipsilateral to the side of OP (7.1 ml vs. 4.5 ml, p = 0.001). Frontal subarachnoid space volume was greater in infants with OP (27.5 ml vs. 0.6 ml in controls, p < 0.0001). Both the suprasellar and perimesencephalic cisterns were of greater caliber in the case group (p = 0.007 and p < 0.0001, respectively). No difference in ventricular size or occipital subarachnoid space volume was noted between groups. The extraventricular CSF spaces in neurologically unimpaired infants with OP are significantly larger than those in age- and sex-matched controls. Enlarged subarachnoid spaces may increase the compliance and malleability of the calvaria and sutures, predisposing to positional deformity. External hydrocephalus may be a fundamental etiological factor in OP.

Cerebrospinal Fluid↗
PubMed1996

Periodontoid calcium pyrophosphate dihydrate deposition disease: "pseudogout" mass lesions of the craniocervical junction.

Between 1984 and 1996, seven patients with symptomatic masses located posterior to the odontoid process and containing calcium pyrophosphate dihydrate crystals were evaluated by the senior author (A.H.M). All patients presented with distal paresthesias and myelopathy and underwent transoral-transpharyngeal resection of the anterior arch of C-I, the odontoid process, and the compressing mass. Histological examination revealed the characteristic changes of calcium pyrophosphate dihydrate (CPPD) deposition disease, with nodular deposits of birefringent rhomboid crystals. On magnetic resonance imaging, the masses appeared predominantly isointense with neural tissue on T1-weighted images and iso-to hyperintense on T2-weighted images. On computerized tomography scans, small area of calcifications within the masses were apparent in all cases. All patients improved postoperatively, with six of seven patients requiring posterior fixation for instability as a second procedure. Calcium pyrophosphate dihydrate deposition causing periodontoid mass lesions is a distinct clinical disease entity that probably is underdiagnosed. In the authors' l opinion, the diagnosis can often be established preoperatively by the distinctive neuroradiological appearance of the masses. Therefore, CPPD deposition disease should be considered in the differential diagnosis of masses of the craniocervical junction, because it is amenable to early surgical intervention. The consulting neuropathologist should be made aware of this diagnostic possibility at the time of surgery.

Aged↗