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Martin H Weiss

Publications and source records attributed to Martin H Weiss.

14 recordsLinked to original sources
PubMed2005

Surgical outcomes in 118 patients with Rathke cleft cysts.

OBJECT: Microscopic Rathke cleft cysts are a common incidental autopsy finding, but some Rathke cleft cysts can become sufficiently large to cause visual impairment, hypothalamic-pituitary dysfunction, and headaches. In this study patients were evaluated pre- and postoperatively to ascertain the clinical significance of surgical intervention on endocrine and visual improvement. Factors correlated with cyst recurrence were also evaluated. METHODS: A retrospective analysis was conducted in 160 patients with Rathke cleft cysts who were treated between 1984 and 1995 and completed at least a 5-year follow-up period. Of these 160 patients, 118 initially exhibited symptoms of visual impairment or endocrine dysfunction, became symptomatic during the follow-up period, or were found to have cyst enlargement. These 118 patients underwent transsphenoidal surgery. Forty-two patients with incidental lesions that demonstrated no growth on magnetic resonance (MR) images were followed up without an operation. Complete resection, as observed on MR images 3 months postoperatively, was obtained in 114 (97%) of 118 patients. Vision improved postoperatively in 57 (98%) of 58 patients. Hypogonadism improved in 11 (18%) of 62 patients, growth hormone deficiency resolved in 14 (18%) of 78 patients, and hypocortisolemia resolved in one (14%) of seven patients. Twenty-two patients (19%) began to exhibit symptoms of diabetes insipidus, which had not been present preoperatively. The total 5-year recurrence rate was 18% (21 of 118 patients), with 12 patients requiring a repeated operation. Surgical and pathological factors that were found to be statistically associated with recurrence were the use of a fat and/or fascial graft for closure (p < 0.01) and the presence of squamous metaplasia in the cyst wall (p < 0.01). The extent of resection of the cyst wall was not associated with an increased rate of recurrence. In 42 (69%) of 61 patients the incidental cysts did not progress on imaging studies or clinically. CONCLUSIONS: This is the largest series of patients with symptomatic Rathke cleft cysts who received operative intervention and participated in the longest postoperative follow up reported in the literature. The high recurrence rate (18%) supports the theory that a relationship exists between a symptomatic Rathke cleft cyst and craniopharyngioma. Improvements in visual and endocrine dysfunction can be expected after surgical decompression of the optic apparatus and the hypothalamic-pituitary axis.

Adolescent↗
PubMed2005

Long-term neurological, visual, and endocrine outcomes following transnasal resection of craniopharyngioma.

OBJECT: The authors report on a cohort of patients with craniopharyngioma treated principally through transnasal (TN) resection and followed up for a minimum of 5 years. More specifically, they evaluate the role of the TN approach in the management of craniopharyngioma. METHODS: Between 1984 and 1994, 68 patients underwent TN resection of craniopharyngiomas at the University of Southern California. The tumor was at least partially cystic in 88% of cases. Four tumors were purely intrasellar, 53 had intra- and suprasellar components, and 11 were exclusively suprasellar. During the same period, 18 patients underwent transcranial (TC) resection of purely suprasellar craniopharyngiomas. Long-term neurological, visual, and endocrine outcomes were reviewed for all patients. In 61 (90%) of 68 patients in the TN group, total resection was achieved, according to 3-month postoperative magnetic resonance images, although four patients suffered a recurrence. Three (43%) of the seven tumors that had been partially resected were enlarged on serial imaging. Fifty-four (87%) of 62 patients with preoperative visual loss experienced improvement in one or both eyes, but two patients (3%) with exclusively suprasellar tumors experienced postoperative visual worsening in one or both eyes. New instances of postoperative endocrinopathy (that is, not present preoperatively) occurred as follows: hypogonadism (eight of 22 cases), growth hormone (GH) deficiency (four of 18 cases), hypothyroidism (11 of 49 cases), hypocortisolemia (nine of 52 cases), and diabetes insipidus (DI; four of 61 cases). One case each of hypocortisolemia and hypothyroidism resolved after surgery. Hyperphagia occurred in 27 (40%) of 68 patients. One patient had short-term memory loss. Postoperative complications included one case of cerebrospinal fluid leak. Among the 18 patients in the TC group, 11 had complete resections. In one case (9%) the tumors recurred. Three (43%) of the seven subtotally resected tumors grew during the follow-up interval. Vision improved in 11 (61%) of 18 cases and worsened in three (17%) as a result of surgery. New instances of postoperative endocrinopathy occurred as follows: hypogonadism (one of six cases), GH deficiency (four of seven cases), hypothyroidism (11 of 14 cases), hypocortisolemia (eight of 15 cases), and DI (nine of 16 cases). No instance of preoperative endocrinopathy was corrected through TC surgery. Four patients (22%) exhibited short-term memory loss and 11 (61%) had hyperphagia after surgery. When compared with those in the TC group, patients in the TN group had shorter hospital stays. CONCLUSIONS: Use of the TN approach can render good outcomes in properly selected patients with craniopharyngioma, particularly when the tumor is cystic. Even in mostly suprasellar cases, an extended TN approach can afford complete resection. Note that endocrine function often worsens after surgery and that postoperative obesity can be a significant problem.

Adolescent↗
PubMed2004

Prolactinomas.

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Antineoplastic Agents↗
PubMed2004

Variations on the standard transsphenoidal approach to the sellar region, with emphasis on the extended approaches and parasellar approaches: surgical experience in 105 cases.

OBJECTIVE: The traditional boundaries of the transsphenoidal approach may be expanded to include the region from the cribriform plate of the anterior cranial base to the inferior clivus in the anteroposterior plane, and laterally to expose the cavernous cranial nerves and the optic canal. We review our combined experience with these variations on the transsphenoidal approach to various lesions of the sellar and parasellar region. METHODS: From 1982 to 2003, we used the extended and parasellar transsphenoidal approaches in 105 patients presenting with a variety of lesions of the parasellar region. This study specifically reviews the breadth of pathological lesions operated and the complications associated with the approaches. RESULTS: Variations of the standard transsphenoidal approach have been used in the following series: 30 cases of pituitary adenomas extending laterally to involve the cavernous sinus, 27 craniopharyngiomas, 11 tuberculum/diaphragma sellae meningiomas, 10 sphenoid sinus mucoceles, 18 clivus chordomas, 4 cases of carcinoma of the sphenoid sinus, 2 cases of breast carcinoma metastatic to the sella, and 3 cases of monostotic fibrous dysplasia involving the clivus. There was no mortality in the series. Permanent neurological complications included one case of monocular blindness, one case of permanent diabetes insipidus, and two permanent cavernous cranial neuropathies. There were four cases of internal carotid artery hemorrhage, one of which required ligation of the cervical internal carotid artery and resulted in hemiparesis. The incidence of postoperative cerebrospinal fluid fistulae was 6% (6 of 105 cases). CONCLUSION: These modifications of the standard transsphenoidal approach are useful for lesions within the boundaries noted above, they offer excellent alternatives to transcranial approaches for these lesions, and they avoid prolonged exposure time and brain retraction. Technical details are discussed and illustrative cases presented.

Adenocarcinoma↗
PubMed2003

Pituitary anatomy and physiology.

The pituitary has been called the master gland of the body because of its central role in governing homeostasis, maintaining the reproductive cycle, and directing the activity of other glands. Housed in the sella turcica of the sphenoid bone at the base of the skull, it has important anatomic relations with the hypothalamus, visual pathways, cavernous sinus, carotid artery, and cranial nerves. The gland originates from two discrete parts of the developing embryo. Rathke's pouch, a dorsal evagination of the stomodeum, forms the anterior and intermediate lobes. The infundibulum, a ventral extension of the diencephalon, forms the posterior lobe. The anterior, intermediate, and posterior lobes of the pituitary gland function as three separate endocrine organs, each characterized by distinct cell populations, secretory products, and regulatory mechanisms. The anterior lobe secretes thyroid stimulating hormone, corticotropin, luteinizing hormone, follicle stimulating hormone, growth hormone, and prolactin. It is regulated by the hypothalamus via the portal vascular system. The posterior lobe releases oxytocin and vasopressin from axon terminals that originate in cell bodies located in the hypothalamus. The intermediate lobe is rudimentary in human beings but produces several hormones whose physiologic significance is only now being established.

Adrenocorticotropic Hormone↗
PubMed2003

Surgical approaches to pituitary tumors.

The transnasal transsphenoidal technique is the preferred approach for pituitary tumors confined primarily to the sella and parasellar regions. In the hands of experienced pituitary surgeons, the rates of morbidity and mortality are extremely low. Extended transsphenoidal approaches have been applied to gain access to the cavernous sinus and suprasellar regions. In some cases, resection via a transcranial approach may be warranted. Endoscopic techniques are being increasingly used and offer a minimally invasive approach and further reduce morbidity associated with the approach to pituitary tumors.

Humans↗
PubMed2003

Role of surgery in the treatment of microprolactinomas.

Prolactinomas are a common cause of reproductive and sexual dysfunction and account for a large proportion of pituitary adenomas. The objectives for treatment of hyperprolactinemia due to microprolactinomas are to suppress excessive hormone secretion, preserve residual pituitary function, and prevent disease recurrence. These objectives may be achieved in most patients harboring microprolactinomas by medical treatment with effective dopamine agonists or microsurgical or endoscopic adenomectomy by an experienced surgeon. The choice of pituitary surgery should be made in consideration of the volume and location of the adenoma, age of the patient, the desire for restoration of fertility, and the efficacy and tolerability of dopamine agonists. The presence of a symptomatic microprolactinoma, especially in a young patient, should remain an indication for micro- or endoscopic tumor removal. This article reviews the emergence of radiosurgery as a treatment for microprolactinomas.

Humans↗
PubMed2003

Craniopharyngioma.

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Journal Article↗
PubMed2003

Zones of approach for craniofacial resection: minimizing facial incisions for resection of anterior cranial base and paranasal sinus tumors.

OBJECTIVE: Anterior cranial base tumors are surgically resected with combined craniofacial approaches that frequently involve disfiguring facial incisions and facial osteotomies. The authors outline three operative zones of the anterior cranial base and paranasal sinuses in which tumors can be resected with three standard surgical approaches that minimize transfacial incisions and extensive facial osteotomies. METHODS: The zones were defined by performing dissections on 10 cadaveric heads and by evaluating radiographic images of patients with anterior cranial base tumors. The three approaches performed on each cadaver were transbasal, transmaxillary, and extended transsphenoidal. RESULTS: Three zones of approach were defined for accessing tumors of the anterior cranial base, nasal cavity, and paranasal sinuses. Zone 1 is exposed by the transbasal approach, which is limited anteriorly by the supraorbital rim, posteriorly by the optic chiasm and clivus, inferiorly by the palate, and laterally by the medial orbital walls. This approach allows access to the entire anterior cranial base, nasal cavity, and the majority of maxillary sinuses. The limitation imposed by the orbits results in a blind spot in the superolateral extent of the maxillary sinus. Zone 2 is exposed by a sublabial maxillotomy approach and accesses the entire maxillary sinus, including the superolateral blind spot and the ipsilateral anterior cavernous sinus. However, access to the anterior cranial base is limited. Zone 3 is exposed by the transsphenoidal approach. This approach accesses the midline structures but is limited by the lateral nasal walls and intracavernous carotid arteries. An extended transsphenoidal approach allows further exposure to the anterior cranial base, clivus, or cavernous sinuses. The use of the endoscope facilitates tumor resection in the nasal cavity and paranasal sinuses. CONCLUSION: The operative zones outlined offer minimally invasive craniofacial approaches to accessing lesions of the anterior cranial base and paranasal sinuses, obviating facial incisions and facial osteotomies. Case illustrations demonstrating the approach selection paradigm are presented.

Adult↗
PubMed2003

Assessment of long-term remission of acromegaly following surgery.

OBJECT: The criteria for remission of acromegaly following transsphenoidal adenoma resection are in evolution. In the present study the authors evaluate the utility of predicting long-term remission by reference to a single fasting growth hormone (GH) level on the 1st postoperative day. METHODS: A retrospective analysis was conducted on 181 patients with acromegaly who underwent transsphenoidal resection between 1973 and 1990 and completed a 5-year follow-up period. Fasting serum GH levels were obtained in all patients on the 1st postoperative day in the absence of exogenous glucocorticoids. All patients participated in a follow-up evaluation lasting at least 5 years, which included measurements of serum insulin-like growth factor-I (IGF-I) levels as an index of acromegalic activity. Among the 181 patients, GH levels ranged from 0 to 8 ng/ml in 131 (72%) on the 1st postoperative day, suggesting biochemical remission. This group included 107 (84%) of the 127 patients with microadenomas, but only 24 (44%) of the 54 with macroadenomas. Nevertheless, 15 (11%) of the 131 patients who initially had attenuated GH levels displayed recurrent acromegaly within the first 2 years (with elevated levels of IGF-I in all cases, and abnormalities appearing on magnetic resonance images in nine cases). Only one of 116 patients in whom the initial postoperative GH level was lower than 2 ng/ml experienced a recurrence, whereas 14 (93%) of the 15 patients with postoperative GH levels between 2.2 and 8 ng/ml subsequently displayed biochemical evidence of acromegaly. CONCLUSIONS: The findings indicate that a fasting morning serum GH level lower than 2 ng/ml on the 1st postoperative day portends long-term biochemical remission of acromegaly, whereas higher levels are a significant marker for recurrent disease.

Acromegaly↗
PubMed2003

Transsphenoidal microsurgical treatment of Cushing disease: postoperative assessment of surgical efficacy by application of an overnight low-dose dexamethasone suppression test.

OBJECT: Transsphenoidal adenomectomy with resection of a defined pituitary adenoma has been the treatment of choice for CD for the last 30 years. Surgical resection, however, may not always result in long-term remission of CD. This is particularly important in light of the high risk of morbidity and mortality in patients in the unsuccessfully treated cushingoid state. As such, it is interesting to identify prognostic factors that may predict the likelihood of long-term remission. METHODS: The authors review their series of 174 patients who have undergone transsphenoidal procedures for CD over a period of 20 years with minimum follow-up periods of 5 years. Selection of these patients was based on clinical, imaging, and laboratory criteria that included serum cortisol levels, loss of diurnal variation in serum cortisol levels, urinary free cortisol concentration, and results of a dexamethasone suppression test, petrosal sinus sampling, and corticotroph-releasing hormone stimulation tests as indicated. All patients who met the biochemical criteria underwent transsphenoidal microsurgery. The authors found an overall rate of remission of 74% at 5 years postoperatively. Patients in whom morning serum cortisol concentrations were lower than 3 microg/dl (83 nmol/L) on postoperative Day 3, following an overnight dexamethasone suppression test, had a 93% chance of remission at the 5-year follow-up examination. Patients with cortisol concentrations higher than this level uniformly failed to achieve long-term remission. CONCLUSIONS: Transsphenoidal microsurgery is an effective means of control for patients with adrenocorticotrophic hormone-producing microadenomas. Clinical outcome correlated well with the size of the tumor, as measured on preoperative imaging studies, and with postoperative morning cortisol levels following an overnight dexamethasone suppression test. Postoperative cortisol levels can be used as a useful prognostic indicator of the likelihood of future recurrence following transsphenoidal adenomectomy in CD.

Adenoma↗
PubMed2002

Tamoxifen-induced growth arrest and apoptosis in pituitary tumor cells in vitro via a protein kinase C-independent pathway.

Protein kinase C (PKC), a kinase family involved in cell signal transduction, is overexpressed in most pituitary adenoma cells. We studied the effect of tamoxifen, an estrogen receptor antagonist and also a protein kinase inhibitor, on pituitary tumor cell proliferation and the induction of apoptosis; and we compared its effects with those of another PKC inhibitor, staurosporine. Tamoxifen induced growth arrest and apoptosis in a mouse pituitary adenoma cell line, AtT20, and in low-passage human primary pituitary tumor cell cultures. Staurosporine also inhibited pituitary tumor cell growth. PKC activity in AtT20 cells was inhibited by staurosporine and by prolonged treatment with phorbol myristate acetate, which down-regulates PKC activity, but not by tamoxifen, at the dosages used to induce apoptosis. Our findings suggest that tamoxifen induces apoptosis in AtT20 cells independent of a classical PKC isozyme pathway.

Adenoma↗
PubMed2002

Predictive value of serum prolactin levels measured immediately after transsphenoidal surgery.

OBJECT: Prolactin-secreting pituitary adenomas may be managed by surgery, medication, radiotherapy, or observation. The authors reviewed a consecutive series of patients who were followed for at least 5 years after surgery to assess the prognostic significance of preoperative factors (tumor size and prolactin level) and an immediate postoperative factor (prolactin level obtained the morning after surgery) on long-term hormonal outcome, thereby clarifying the indications for surgical removal of tumor, the definition of successful treatment outcomes, and the nature of "recurrent" tumors. METHODS: Between 1979 and 1991, 241 patients with prolactinomas underwent transsphenoidal resection. Nineteen patients were lost to follow-up review, whereas the remaining 222 patients underwent measurement of their prolactin levels on postoperative Day 1 (POD 1), at 6 and 12 weeks, and every 6 months thereafter for a minimum of 5 years. On POD 1, prolactin levels in 133 patients (Group 1) were lower than 10 ng/ml, in 43 patients (Group 2) between 10 and 20 ng/ml, and in 46 patients (Group 3) higher than 20 ng/ml. At 6 and 12 weeks, normal prolactin levels (< or = 20 ng/ml) were measured in 132 (99%) of the 133 patients in Group 1 but only in 32 (74%) of the 43 patients in Group 2. By 5 years postoperatively, normal levels of prolactin were still measured in 130 patients (98%) in Group 1 compared with only five patients (12%) in Group 2. No patient with a prolactin level lower than 3 ng/ml on POD 1 was found to have an elevated hormone level at 5 years. The likelihood of a long-term chemical cure was greater for patients with microadenomas (91% cure rate) than for those with macroadenomas (33%). Preoperative prolactin levels also correlated with hormonal outcome. CONCLUSIONS: Prolactin levels lower than 10 ng/ml on POD 1 predict a long-term chemical cure in patients with microadenomas (100% cure rate) and those with macroadenomas (93% cure rate). In contrast, a cure is not likely to be obtained in patients with normal levels ranging between 10 and 20 ng/ml on POD 1 if they harbor macroadenomas (0% cure rate). A recurrence reported several years after surgery probably represents the presence of persistent tumor that was not originally removed. If the initial operation was performed by an experienced surgeon, however, reoperation is not likely to yield a chemical cure.

Adolescent↗