Joseph V. McDonald

Use of Vicryl (polyglactin 910) mesh to limit epidural scar formation after laminectomy.

A variety of substances have been used at laminectomy sites to prevent postoperative epidural scarring. Free grafts of autologous subcutaneous fat are commonly used both clinically and experimentally. The free fat grafts usually survive, but decrease in size by about 50%. Postoperatively, subcutaneous seroma has been observed with the use of fat grafts, as well as recurrent symptoms of neural compression by the graft that required additional operations. When compared to the use of free grafts after laminectomy in dogs, Vicryl mesh produced slightly more scarring, but consistently less than that observed in control animals. The Vicryl mesh was resorbed by a minimal chronic inflammatory response over about 45 days. Seven of 11 fat-grafted zones showed signs of necrosis, at times with a greater collection of inflammatory cells than that associated with the Vicryl mesh. Of the 4 fat-grafted zones that showed good survival, 2 had gross evidence of neural compression. No surgical zone treated with Vicryl mesh exhibited evidence of neural compression. In view of these results, the use of Vicryl mesh at laminectomy sites may be a safer method of limiting postoperative epidural scar formation.

TRANSIENT HYPOGONADOTROPHIC HYPOGONADISM AFTER HEAD TRAUMA: EFFECTS ON STEROID PRECURSORS AND CORRELATION WITH SYMPATHETIC NERVOUS SYSTEM ACTIVITY

Transient hypogonadotrophic hypogonadism commonly occurs after major medical insults. Because data on testosterone precursors are sparse and because little is known about the aetiology of these changes, we studied the interactions of traumatic brain injury with gonadal steroidogenesis and with sympathetic nervous system activation. Patients were divided into two groups based upon the severity of neurological dysfunction using the Glasgow Coma Score (GCS); Group 1 > 8, Group 2 ≥ 8. Group 1 was further divided into those patients treated (Group 1b) and those not treated with dexamethasone (Group 1a). Plasma levels of testosterone, androstenedione, 17‐hydroxyprogesterone, DHEA sulphate, cortisol, LH, FSH, and the catecholamines noradrenaline (NE), adrenaline (EPI) and dopamine were measured in 31 acutely brain injured men, aged 18–95, shortly after their accident and 4 days later. In all patients, NE and EPI were elevated on admission (NE: 841 ± 105 (SEM) pg/ml; EPI: 191 ± 32 pg/ml and there were highly significant inverse correlations between admission NE (r=−0·52, P > 0·003) and EPI (r=0·44, P > 0·02) levels and day 4 testosterone concentrations. Testosterone fell 53% (P>0·001) in 13 Group la men, but only 25% (P=NS) in the less severely injured. Similar reductions occurred in cortisol and the steroid precursors. However, only testosterone, 17‐hydroxyprogesterone, and DHEA sulphate levels were significantly lower than normal on day 4. LH and FSH levels were also significantly reduced from elevated admission levels. In the eight men treated with dexamethasone (8–40 mg/ml) (Group 1b), the decrease in testosterone, LH and FSH concentrations were similar to those present in Group 1a. Thus, severe traumatic brain injury leads to hypogonadotrophic hypogonadism which affects testosterone and its precursors. The magnitude of the hormonal dysfunction is dependent upon the severity of the neurological insult. Finally, the decrease in testosterone is significantly correlated with admission catecholamine levels, which may suggest a role for the sympathetic nervous system (SNS) in mediating this response in men.

Ventriculoperitoneal Shunts in Children: Factors Affecting Shunt Survival

The survival of ventriculoperitoneal cerebrospinal fluid shunts inserted during the past 11 years at the University of Rochester was reviewed. Half the shunts inserted failed by 23 months after insertion, although shunt survival has improved since 1981. Shunt survival was found to be affected by etiology. For example, children with neural tube defects had longer shunt survival than children with hydrocephalus from other etiologies. Children whose shunts were inserted prior to their first birthday, and children whose shunts were inserted when they weighed less than 3,000 g, had worse shunt survival. The manner in which factors such as age, weight and etiology affect shunt survival are uncertain, yet it is clear that children with hydrocephalus are a heterogeneous group. Studies that fail to consider this heterogeneity may result in invalid conclusions.

Thyroid test abnormalities in traumatic brain Injury: Correlation with neurologic impairment and sympathetic nervous system activation

Acute illness is well known to affect thyroid function, but there are few studies correlating the severity of the underlying medical problem with indexes of thyroid function and little is known about its cause. Traumatically brain-injured patients were selected because they were a relatively homogeneous, previously healthy group with a condition whose severity was readily quantifiable. In 66 such patients, the relationships between changes in thyroid function tests (thyroxine, free thyroxine, triiodothyronine, reverse triiodothyronine, and thyrotropin levels), catecholamine and cortisol concentrations measured on admission and again four days after the accident, and neurologic function assessed by the Glasgow Coma Score (GCS) were studied. Triiodothyronine and thyroxine levels fell significantly within 24 hours of injury. Four days after the accident, patients with the greatest neurologic dysfunction had the lowest triiodothyronine and thyroxine levels; significant correlations were present between the Day 4 GCS and concomitant thyroxine (r = 0.47, p less than 0.0001), free thyroxine (r = 0.32, p less than 0.02), and triiodothyronine (r = 0.50, p less than 0.0001) levels. Reverse triiodothyronine values remained unchanged throughout the study even in the most severely affected patients; the rise in thyrotropin levels was not significant (1.2 +/- 0.2 to 1.7 +/- 0.3 microU/ml, p = NS). Patients who died or remained vegetative had thyroxine and triiodothyronine levels 30 percent to 50 percent lower than those who had a good recovery (p less than 0.05). Highly significant correlations were present between Day 4 thyroxine and triiodothyronine levels and admission and Day 4 norepinephrine and epinephrine concentrations. There was no association between admission or concomitant cortisol levels and thyroid function on Day 4; treatment with high-dose dexamethasone did not influence these indexes. Thus, patients with traumatic brain injury exhibit a gradient of thyroid dysfunction that occurs promptly, is dependent upon the degree of neurologic impairment, and reflects ultimate outcome. The significant association with catecholamine levels suggests a role for sympathetic nervous system activation in its causation, independent of a generalized stress response, since there is no correlation of thyroid test abnormality with the degree of adrenocortical secretion.

Intramedullary melanotic schwannoma of the cervical spinal cord: Report of a case

We present a case report of a patient with an intramedullary tumor of the midcervical cord. At surgery, the lesion was found to be highly pigmented, and pathological analysis revealed a melanotic schwannoma. Intramedullary schwannomas and melanotic schwannomas are exceedingly rare. This is the second reported case of an intramedullary melanotic schwannoma of the central nervous system.

Craniopharyngiomas: fluctuation in cyst size following surgery and radiation therapy

Patients with craniopharyngiomas who demonstrate cyst enlargement after surgery and radiation are often presumed to be treatment failures. Therapeutic approaches in various centers include repetitive cyst aspirations, surgical reexcision, and installation of cytotoxic agents such as methotrexate, 32P, or 198Au. Each intervention has associated severe or even lethal side effects. Not all patients with craniopharyngioma who have cystic enlargement after primary therapy require an intervention, as demonstrated by 4 patients recently managed in the University of Rochester Medical Center. Since 1978, when computed tomography was routinely in use, we have managed 11 patients with craniopharyngiomas who were treated with surgery followed by radiation therapy. Three of these patients demonstrated post-irradiation enlargement of the residual cystic component followed by a decrease in size without surgical intervention. An additional patient showed cystic growth followed by stabilization of size. It is noteworthy that the cyst enlarged within the first 5 months after radiation therapy in the 3 patients who subsequently demonstrated a diminution in the size of their cysts. This suggests that the mechanism for cyst formation remained intact and subsequently abated because of a radiation-induced lesion. We conclude that after treatment with surgery and radiation therapy, the cystic component of craniopharyngiomas may increase and, without intervention, subsequently decrease in size. Thus, in the asymptomatic patient who demonstrates cystic growth soon after primary therapy, close observation alone may be warranted.

Late solitary cerebral metastases from renal cell carcinoma: Report of two cases

We report two cases of solitary cerebral metastases from renal cell carcinoma 15 and 18 years after nephrectomy. In a review of the literature, only two cases of solitary brain metastasis from renal cell carcinoma with latency periods greater than 10 years have been documented. Our two cases represent the longest latency periods reported between nephrectomy and detection of a solitary cerebral metastasis. Histologic examination and immunohistochemical profile of the primary renal tumors and metastatic cranial tumors showed identical morphology and immunophenotype.

Anterior third ventricle meningioma in a child.

A case report of a meningioma in the anterior part of the third ventricle of a 10-year-old boy is presented. The tumor was successfully removed through a right trans-cortical ventricular approach.

Meningeal hemangiopericytoma of the posterior fossa and thoracic spinal epidural space: case report.

The rare combination of spinal and intracranial meningeal hemangiopericytomas in the same patient is reported. The coexistence of cerebral and spinal meningiomas of all histological subtypes is distinctly uncommon with only nine cases found in the literature.

Meningeal Hemangiopericytoma of the Posterior Fossa and Thoracic Spinal Epidural Space

ABSTRACTThe rare combination of spinal and intracranial meningeal hemangiopericytomas in the same patient is reported. The coexistence of cerebral and spinal meningiomas of all histological subtypes is distinctly uncommon with only nine cases found in the literature.