Neurosurgical management of acromegaly. Results in 82 patients treated between 1972 and 1977

Growth hormone secreting pituitary adenomas show distinct extrasellar extension patterns compared to nonfunctional pituitary adenomas

PURPOSE

Patterns of extension of pituitary adenomas (PA) may vary according to PA subtype. Understanding extrasellar extension patterns in growth hormone PAs (GHPA) vis-a-vis nonfunctional PAs (NFPAs) may provide insights into the biology of GHPA and future treatment avenues.

METHODS

Preoperative MR imaging (MRI) in 179 consecutive patients treated surgically for NFPA (n = 139) and GHPA (n = 40) were analyzed to determine patterns of extrasellar growth. Extension was divided into two principal directions: cranio-caudal (measured by infrasellar/suprasellar extension), and lateral cavernous sinus invasion (CSI) determined by Knosp grading score of 3-4. Suprasellar extension was defined as tumor extension superior to the tuberculum sellae- dorsum sellae line, and inferior extension as invasion through the sellar floor into the sphenoid sinus or clivus. Categorical analysis was performed using Fisher's exact test.

RESULTS

GHPAs were overall more likely to remain purely intrasellar compared to NFPA (50% vs 26%, p < 0.001). GHPAs, however, were 7 times more likely to exhibit isolated infrasellar extension compared to NFPA (20% vs 2.8%, p = 0.001). Conversely, NFPAs were twice as likely to exhibit isolated suprasellar extension compared to GHPA (60% vs 28%, p < 0.001), as well as combined suprasellar/infrasellar extension (25% vs 3%, p = 0.011). There were no overall differences in CSI between the two subgroups.

DISCUSSION

GHPA and NFPA demonstrate distinct extrasellar extension patterns on MRI. GHPAs show proclivity for inferior extension with bony invasion, whereas NFPAs are more likely to exhibit suprasellar extension through the diaphragmatic aperture. These distinctions may have implications into the biology and future treatment of PAs.

Predictors of postoperative biochemical remission in acromegaly

PURPOSE

Acromegaly is a rare neuroendocrine condition that can lead to significant morbidity. Despite China's vast population size, studies on acromegaly remain sparse. This study aimed to investigate the clinical characteristics and predictors of biochemical remission after surgery for acromegaly using the China Acromegaly Patient Association (CAPA) database.

METHODS

A retrospective nationwide study was conducted using patient-reported data from CAPA database between 1998 and 2018. The principal component analysis (PCA) and logistic regression analysis were employed to determine independent predictors of biochemical remission at 3 months in patients after surgery.

RESULTS

Of the 546 surgical cases (mean age: 36.8 years; 59.5% females), macroadenomas and invasive tumors (Knosp score 3-4) were 83.9% and 64.1%, respectively. Ninety-five percent of patients were treated with endonasal surgery and 36.8% exhibited biochemical remission at 3-months postoperatively. The following independent predictors of biochemical remission were identified: preoperative growth hormone (GH) levels between 12 and 28 μg/L [odds ratio (OR) = 0.58; 95% confidence interval (CI), 0.37-0.92; p = 0.021], preoperative GH levels > 28 μg/L (OR = 0.55; 95% CI, 0.34-0.88; p = 0.013), macroadenoma (OR = 0.56; 95% CI, 0.32-0.96; p = 0.034), giant adenomas (OR = 0.14; 95% CI, 0.05-0.38; p < 0.001), Knosp score 3-4 (OR = 0.37; 95% CI, 0.24-0.57; p < 0.001), and preoperative medication usage (OR = 2.32; 95% CI, 1.46-3.70; p < 0.001).

CONCLUSIONS

In this nationwide study spanning over two decades, we highlight that higher preoperative GH levels, large tumor size, and greater extent of tumor invasiveness are associated with a lower likelihood of biochemical remission at 3-months after surgery, while preoperative medical therapy increases the chance of remission.

Microsurgical versus endoscopic transsphenoidal resection for acromegaly: a systematic review of outcomes and complications

PURPOSE

The aim of this systematic review is to evaluate the long-term endocrine outcomes and postoperative complications following endoscopic vs. microscopic transsphenoidal resection (TSR) for the treatment of acromegaly.

METHODS

A literature review was performed, and studies with at least five patients who underwent TSR for acromegaly, reporting biochemical remission criteria and long-term remission outcomes were included. Data extracted from each study included surgical technique, perioperative complications, biochemical remission criteria, and long-term remission outcomes.

RESULTS

Fifty-two case series from 1976 to 2016 met the inclusion criteria, comprising 4375 patients. Thirty-six reports were microsurgical (n = 3144) and 13 were endoscopic (n = 940). Three studies compared microsurgical (n = 111) to endoscopic TSR outcomes (n = 180). The overall initial and long-term remission rates were 58.2 vs. 57.4% and 69.2 vs. 70.2% for the microsurgical and endoscopic groups, respectively. For microadenomas, the initial and long-term remission rates were 77.6 vs. 82.2% and 76.9 vs. 73.5% for microsurgical and endoscopic approaches, respectively. For macroadenomas, the initial and long-term remission rates were 46.9 vs. 60.0% and 40.2 vs. 61.5% for microsurgical and endoscopic approaches, respectively. The rates of postoperative CSF leak were 3.0 vs. 2.3% for the microscopic and endoscopic groups, respectively. The rates of hypopituitarism and transient diabetes insipidus were 6.7 vs. 6.4% and 9.0 vs. 7.8% for the microscopic and endoscopic groups, respectively.

CONCLUSIONS

Both endoscopic and microsurgical approaches for TSR of growth hormone-secreting adenomas are viable treatment options for patients with acromegaly, and yield similarly high rates of remission under the most current consensus criteria.

Acromegaly: surgical results in 548 patients

PURPOSE

The goal of this study was to quantified the results of microsurgery, in all the patients with acromegaly treated by the same endocrinologist and the same surgeon between 1975 and 2015.

METHODS

A series of 548 patients with acromegaly were operated and followed-up from 6 months to 40 years. Patients were selected according to five criteria: (1) Operated by the same surgeon. (2) No previous treatment. (3) Complete endocrinological preoperative studies including GH, OGTT, IGF-I, PRL test and TC/MRI. (4) Complete postoperative endocrinological evaluation for at least one determination of GH, OGTT, PRL test and IGF-I six months after surgery. (5) All the patients were supervised by the same endocrinologist.

RESULTS

Microadenomas were present in 119 patients and 109 (91,5%) achieved remission. Non invasive macroadenomas were present in 200 patients and 164 achieved remission (82%). Results were worse for invasive macroadenomas but even with great invasions some patients achieved clinical remission. Follow-up range from 6 months to 40 years (mean 3.3 ± 2.3) A long term follow-up of 15 years was achieved in 61 patients. Four of them had a recurrence 4, 7, 8, 12 years after surgery (6.5%). There was not mortality and the rate of complications was low.

CONCLUSIONS

Surgery remains the first line of therapy for a majority of acromegalic patients. This series proves to be very valuable in circumscribed adenomas but also in invasive tumours. Levels of GH and IGF-I were decreased in almost all the patients without remission.

Biochemical investigations in diagnosis and follow up of acromegaly

Measurements of human growth hormone (GH) and insulin-like growth-factor I (IGF-I) are cornerstones in the diagnosis of acromegaly. Both hormones are also used as biochemical markers in the evaluation of disease activity during treatment. Management of acromegaly is particularly challenging in cases where discordant information is obtained from measurement of GH concentrations following oral glucose load and from measurement of IGF-I. While in some patients biological factors can explain the discrepancy, in many cases issues with the analytical methods seem to be responsible. Assays used by endocrine laboratories to determine concentrations of GH and IGF-I underwent significant changes during the last decades. While generally leading to more sensitive and reproducible methods, these changes also had considerable impact on absolute concentrations measured. This must be reflected by updated decision limits, cut-offs and reference intervals. Since different commercially available assays do not agree very well, method specific interpretation of GH and IGF-I concentrations is required. This complexity in the interpretation of hormone concentrations is not always appropriately reflected in laboratory reports, but also not in clinical guidelines reporting decision limits not related to a specific analytical method. The present review provides an overview about methodological and biological variables affecting the biochemical assessment of acromegaly in diagnosis and follow up.

Multimodal Navigation in Endoscopic Transsphenoidal Resection of Pituitary Tumors Using Image-Based Vascular and Cranial Nerve Segmentation: A Prospective Validation Study

BACKGROUND

Transsphenoidal surgery (TSS) is the most common approach for the treatment of pituitary tumors. However, misdirection, vascular damage, intraoperative cerebrospinal fluid leakage, and optic nerve injuries are all well-known complications, and the risk of adverse events is more likely in less-experienced hands. This prospective study was conducted to validate the accuracy of image-based segmentation coupled with neuronavigation in localizing neurovascular structures during TSS.

METHODS

Twenty-five patients with a pituitary tumor underwent preoperative 3-T magnetic resonance imaging (MRI), and MRI images loaded into the navigation platform were used for segmentation and preoperative planning. After patient registration and subsequent surgical exposure, each segmented neural or vascular element was validated by manual placement of the navigation probe or Doppler probe on or as close as possible to the target.

RESULTS

Preoperative segmentation of the internal carotid artery and cavernous sinus matched with the intraoperative endoscopic and micro-Doppler findings in all cases. Excellent correspondence between image-based segmentation and the endoscopic view was also evident at the surface of the tumor and at the tumor-normal gland interfaces. Image guidance assisted the surgeons in localizing the optic nerve and chiasm in 64% of cases. The mean accuracy of the measurements was 1.20 ± 0.21 mm.

CONCLUSIONS

Image-based preoperative vascular and neural element segmentation, especially with 3-dimensional reconstruction, is highly informative preoperatively and potentially could assist less-experienced neurosurgeons in preventing vascular and neural injury during TSS. In addition, the accuracy found in this study is comparable to previously reported neuronavigation measurements. This preliminary study is encouraging for future prospective intraoperative validation with larger numbers of patients.

Fusiform dilatation of the cavernous carotid artery in acromegalic patients

BACKGROUND

Surgeons undertaking transsphenoidal surgery in patients with acromegaly confront multiple unique challenges secondary to the anatomic alterations caused by growth hormone-secreting tumors. The senior author has noted a fusiform dilatation of the cavernous carotid artery in many acromegalic patients. The authors aim to quantify this dilatation and correlate it with potential contributing factors.

METHODS

Clinical and radiographic data were retrospectively assessed in acromegalic patients undergoing transsphenoidal surgery from 2000 through 2011. Randomly selected patients with nonsecreting pituitary adenomas were used as the control cohort. Demographic information, comorbidities, and preoperative growth hormone and insulin-like growth factor-1 levels were recorded. Magnetic resonance (MR) imaging variables included tumor size, diameters of the petrous, cavernous, and supraclinoid segments of the carotid artery, and extent and location of cavernous sinus invasion. Independent correlations between acromegaly and each variable were assessed with multivariate regression analysis.

RESULTS

Forty randomly selected patients with growth hormone-secreting adenomas who underwent surgery and had MR imaging with thin coronal slices of the pituitary region were enlisted in our study cohort. The mean age was 45.7 years. Forty-two males (52.5 %) were included in the study. Mean carotid artery diameter measurements for acromegalic and control patients, respectively, were 4.2 vs. 3.8 mm (petrous carotid), 5.0 vs. 4.0 mm (cavernous carotid), and 3.3 vs. 2.9 mm (supraclinoid carotid). Multivariate analysis showed only age and cavernous carotid diameter were statistically significant independent variables (p = 0.02, p < 0.001, respectively). Age, tumor size, growth-hormone or insulin-like growth factor-1 levels, and cavernous sinus invasion did not correlate with cavernous carotid artery diameter.

CONCLUSIONS

In patients with acromegaly, there is a fusiform dilatation of the cavernous carotid artery that must be considered when planning transsphenoidal surgery.

Endoscopic endonasal transsphenoidal approach: an additional reason in support of surgery in the management of pituitary lesions

The outcome of endoscopic endonasal transsphenoidal surgery in 10 patients with pituitary adenomas was compared with that of traditional transnasal transsphenoidal approach (TTA) in 20 subjects. Among the 10 individuals subjected to "pure endoscopy," 2 had a microadenoma, 1 an intrasellar macroadenoma, 4 had a macroadenoma with suprasellar expansion, 2 had a macroadenoma with supra-parasellar expansion, and 1 a residual tumor; 5 had acromegaly and 5 had a nonfunctioning adenoma (NFA). Among the patients subjected to TTA, 4 had a microadenoma, 2 had an intrasellar macroadenoma, 6 had a macroadenoma with suprasellar expansion, 4 had a macroadenoma with supra-parasellar expansion, and 4 had a residual tumor; 9 patients had acromegaly, 1 hyperprolactinemia, 1 Cushing's disease, and 9 a NFA. At the macroscopic evaluation, tumor removal was total (100%) after endoscopy in 9 patients and after TTA in 14 patients. Six months after surgery, magnetic resonance imaging (MRI) confirmed the total tumor removal in 21 of 23 patients (91.3%). Circulating growth hormone (GH) and insulin-like growth factor-I (IGF-I) significantly decreased 6 months after surgery in all 14 acromegalic patients: normalization of plasma IGF-I levels was obtained in 4 of 5 patients after the endoscopic procedure and in 4 of 9 patients after TTA. Before surgery, pituitary hormone deficiency was present in 14 out of 30 patients: pituitary function improved in 4 patients, remaining unchanged in the other 10 patients. Visual field defects were present before surgery in 4 patients, and improved in all. Early surgical results in the group of 10 patients who underwent endoscopic pituitary tumor removal were at least equivalent to those of standard TTA, with excellent postoperative course. Postsurgical hospital stay was significantly shorter (3.1 +/- 0.4 vs. 6.2 +/- 0.3 days, p < 0.001) after endoscopy as compared to TTA.

Transsphenoidal surgery in patients with acromegaly: operative strategies for overcoming technically challenging anatomical variations

OBJECT

In addition to difficulties with anesthetic and medical management, transsphenoidal operations in patients with longstanding acromegaly are associated with inherent intraoperative challenges because of anatomical variations that occur frequently in these patients. The object of this study was to review the overall safety profile and anatomical/technical challenges associated with transsphenoidal surgery in patients with acromegaly.

METHODS

The authors performed a retrospective analysis of 169 patients who underwent endoscopic transsphenoidal operations for growth hormone-secreting adenomas to assess the incidence of surgical complications. A review of frequently occurring anatomical challenges and operative strategies employed during each phase of the operation to address these particular issues was performed.

RESULTS

Of 169 cases reviewed, there was no perioperative mortality. Internal carotid artery injury occurred in 1 patient (0.6%) with complex sinus anatomy, who remained neurologically intact following endovascular unilateral carotid artery occlusion. Other complications included: significant postoperative epistaxis (5 patients [3%]), transient diabetes insipidus (5 patients [3%]), delayed symptomatic hyponatremia (4 patients [2%]), CSF leak (2 patients [1%]), and pancreatitis (1 patient [0.6%]). Preoperative considerations in patients with acromegaly should include a cardiopulmonary evaluation and planning regarding intubation and other aspects of the anesthetic technique. During the nasal phase of the transsphenoidal operation, primary challenges include maintaining adequate visualization and hemostasis, which is frequently compromised by redundant, edematous nasal mucosa and bony hypertrophy of the septum and the nasal turbinates. During the sphenoid phase, adequate bony removal, optimization of working space, and correlation of imaging studies to intraoperative anatomy are major priorities. The sellar phase is frequently challenged by increased sellar floor thickness, distinct patterns of tumor extension and bony invasion, and anatomical variations in the caliber and course of the internal carotid artery. Specific operative techniques for addressing each of these intraoperative challenges are discussed.

CONCLUSIONS

Transsphenoidal surgery in patients with longstanding acromegaly frequently poses greater challenges than operations for other types of sellar lesions, yet these challenges may be safely and effectively overcome with the anticipation of specific issues and implementation of various intraoperative techniques.

Patterns of extrasellar extension in growth hormone–secreting and nonfunctional pituitary macroadenomas

Object

Growth patterns of pituitary adenomas have been observed to vary by histopathological subtype. The authors aimed to analyze variations in the patterns of extrasellar extension of nonfunctional macroadenomas (NFMAs) and growth hormone (GH)–secreting macroadenomas.

Methods

A retrospective review was conducted of data obtained in 75 patients who underwent transsphenoidal operations for histologically confirmed NFMAs (50 patients) and GH-secreting macroadenomas (25 patients) at the Brigham and Women's Hospital over an 18-month period. Patients with microadenomas and prior operations were excluded from the analysis. Preoperative MR images were reviewed to assess patterns of extrasellar extension in the varying tumor subtypes.

Results

The mean maximal tumor diameter in NFMAs and GH-secreting macroadenomas was 26 and 16 mm, respectively (p < 0.0001). Extension of the NFMAs occurred into the following regions: infrasellar, 23 patients (46%); suprasellar, 41 patients (82%); and cavernous sinus, 20 patients (40%). Extension of GH-macroadenomas occurred into the following regions: infrasellar, 18 patients (72%); suprasellar, 4 patients (16%); and cavernous sinus, 4 patients (16%). Compared with GH-adenomas, NFMAs were more likely to develop suprasellar extension (82% vs 16%, p < 0.0001), cavernous sinus extension (40% vs 16%, p = 0.04), and isolated suprasellar extension (30% vs 4%, p = 0.0145). GH-macroadenomas had higher overall rates of infrasellar extension (72% vs 46%, p < 0.05), and isolated infrasellar extension (52% vs 6%, p < 0.0001). Of the 13 GH-macroadenomas with isolated infrasellar extension, 5 (42%) met WHO criteria for atypical adenomas.

Conclusions

Substantial differences in extrasellar growth patterns were observed among varying histological subtypes of pituitary macroadenomas. Despite smaller tumor diameters, GH-macroadenomas demonstrated a proclivity for infrasellar extension, whereas NFMAs exhibited preferential extension into the suprasellar region.

Normal growth hormone secretion is rare after microsurgical normalization of growth hormone levels in acromegaly

The effect of microsurgery on growth hormone (GH) secretion was studied in 34 patients with acromegaly. All patients showed enlarged sella volumes according to encephalography and macroadenomas at surgery. Preoperative GH levels were elevated in all 34 patients and 14 had concomitant hyperprolactinemia. There was a correlation between basal GH levels and sella size. Visual field defects, suprasellar extension, long duration of the disease, hyperprolactinemia and aneuploidy were noted in patients with low as well as high levels of GH preoperatively. The average reduction of GH levels in the total series was 71 +/- 21% (mean +/- SD). A notably similar reduction of GH levels was seen regardless of preoperative GH levels, concomitant hyperprolactinemia, visual field defects, size of the adenoma, invasive growth or increasing experience of the surgeon. Therefore, normal GH levels after surgery were reached mainly in patients with moderate GH increments preoperatively. GH levels were normalized by surgery in 15 patients but only four of these showed normal GH response to TRH and iota-dopa tests. Thus, only four patients (12%) fulfilled these criteria for cure of GH homeostasis.

Transsphenoidal approaches to the pituitary: a progression in experience in a single centre

BACKGROUND

Evolving of a single centre by means of different transsphenoidal approaches during the survey of methodological advances in pituitary surgery is presented.

MATERIALS AND METHODS

Ninety-three consecutive patients with pituitary adenomas underwent transphenoidal pituitary operations at Gulhane Military Medical Academy from January 1996 to October 2007. Retrospective chart-based analysis of the surgical methods of transsphenoidal pituitary adenoma operations were done. Surgical methods were described. Outcomes and complications were presented. Attention is focused on the methodology of different surgical techniques of pituitary surgery.

FINDINGS

During the evaluation period, 12 Sublabial approaches (1996-1998), 13 transseptal transsphenoidal approaches (1999-2000), 15 endonasal transsphenoidal approaches (2000-2004), 25 endoscopy assisted endonasal approaches (2002-2006) and 28 pure endoscopic endonasal approaches (2006-2007) were performed.

CONCLUSIONS

Technologic advancements in endoscopy and gaining experience in pituitary surgery drives neurosurgeons toward less invasive approaches.

Early postoperative indicators of late outcome in acromegalic patients

OBJECTIVE

According to current criteria, normalised serum IGF-1 and glucose-suppressed GH < 1 ng/ml are indicators of biochemical cure in acromegalic patients. We performed a retrospective study to assess whether the attainment of these values in the early postoperative period was predictive of future IGF-1 normalisation and disease inactivity.

PATIENTS, MEASUREMENTS AND RESULTS

Between 1978 and 1999, 78 acromegalic patients underwent resection for pituitary adenomas. At the end of the mean follow-up period of 7 years, 43 (55.1%) showed normalised IGF-1 levels and no disease activity. In 51 cases, both IGF-1 and glucose-suppressed GH were examined within the first postoperative month. Of this group, all 19 patients who had early glucose-suppressed GH < 1 ng/ml and were treated by surgery alone maintained normal IGF-1 levels throughout the follow-up; four of them demonstrated delayed (i.e. more than 30 days after the operation) IGF-1 normalisation. In 19 patients with early glucose-suppressed GH levels of 1-4 ng/ml, seven of 11 patients with early normalised IGF-1 and two of eight patients with early IGF-1 elevation manifested eventual IGF-1 normalisation. However, none of the 13 patients with early glucose-suppressed GH > 4 ng/ml attained IGF-1 normalisation. Both univariate and multivariate analyses indicated that early glucose-suppressed GH was a significant factor for predicting late normalised IGF-1; the cut-off value was 1.5 ng/ml (sensitivity: 0.97; specificity: 0.75; odds ratio: 90).

CONCLUSION

The attainment of both normalised IGF-1 and glucose-suppressed GH < 1 ng/ml, even during the early postoperative period, suggests absolute cure in acromegalic patients. However, even in patients who do not meet both criteria within the first postoperative month, glucose-suppressed GH < 1.5 ng/ml, or glucose-suppressed GH < 4 ng/ml coupled with early IGF-1 normalisation indicate the possibility of eventual normalisation of IGF-1 and disease inactivity without adjuvant therapy. These postoperative parameters may be useful for assessing the desirability of further treatment.

Novel closure technique for the endonasal transsphenoidal approach. Technical note

Transsphenoidal microsurgery has been the standard approach to sellar lesions since the repopularization of the technique with modifications by Dott, Guiot, and Hardy. The endonasal transseptal transsphenoidal approach, as introduced by Hirsch, is still commonly used by pituitary surgeons to remove lesions of the sellar and parasellar region. One disadvantage of this approach is that the submucosal dissection requires postoperative nasal packing, which is a source of discomfort in patients who undergo transsphenoidal surgery. The authors describe a novel closure technique for the unilateral endonasal transsphenoidal approach that eliminates the need for full nasal packing, minimizing postoperative rhinological morbidity. This technique has been performed in 67 patients harboring sellar and parasellar lesions. All patients recovered rapidly without significant rhinological sequelae.

Mortality in 154 surgically treated patients with acromegaly--a 10-year follow-up survey

To determine the effects of surgery and adjuvant therapy on the mortality rate of Japanese patients with acromegaly, 154 surgically treated patients were followed until death or December 2000. Mean follow-up period was 10.0 +/- 6.5 (SD) years. Postoperative GH levels, mean values of GH levels measured in the first postoperative month, were <2.5 ng/mL in 73 (47.4%), 2.5-5.0 ng/mL in 50 (32.5%), and >5.0 ng/mL in 31 patients (20.1%). Three of 123 patients with postoperative GH levels <5.0 ng/mL underwent a second transsphenoidal surgery (TSS), the other 120 received no further treatment. Additional treatments, including second TSS, medical treatment, and gamma-knife irradiation for residual tumor, were administered to 25 of 31 patients whose postoperative GH was >5.0 ng/mL. Among the total 154 patients surveyed, 11 (7.1%) died during the follow-up period. The standard mortality ratio (SMR) was 1.17, not different from age- and sex-matched controls. The SMR of the 72 patients with postoperative GH <2.5 ng/mL was better than that of the 51 patients whose postoperative GH was 2.5-5.0 ng/mL (1.09 vs. 1.64); however, the difference was not statistically significant. In conclusion, TSS and adequate adjuvant treatment decreased the excess mortality rate of acromegalics to nearly the same level as that of the general Japanese population.

Growth pattern and rate in residual nonfunctioning pituitary adenomas: correlations among tumor volume doubling time, patient age, and MIB-1 index

OBJECT

Surgical cure can be achieved in pituitary adenomas when they are completely removed. It is controversial whether postoperative radiation therapy should be given to prevent recurrence, and whether an early reoperation should be performed for residual adenomas, because we have little information about the natural history of postoperative residual adenomas.

METHODS

The residual tumor volume was serially measured in 40 nonfunctioning pituitary adenomas (NFPAs) and the tumor volume doubling time (TVDT) was calculated. Correlations between the patients' age, tumor volume, log TVDT, and MIB-1 index were examined. Other factors including the patient's sex, cavernous sinus (CS) invasion by the tumor, or presence of an intratumoral cyst were analyzed to assess their influence on the TVDT. Values are expressed as the means +/- standard deviations. Thirty-eight adenomas increased in volume and two decreased during a follow-up period ranging from 4 to 141 months (mean 52.5 months). Exponentially linear tumor growth was observed in the 38 growing adenomas regardless of the residual tumor volume, with the TVDT ranging from 506 to 5378 days (mean 1836 days). The patients' age was 57.1 +/- 15.7 years (range 15-79 years), the tumor volume at the beginning of the magnetic resonance imaging observation period was 2.5 +/- 2.2 cm3 (range 0.07-14.5 cm3), and the MIB-1 index was 0.73 +/- 0.68% (range 0.1-2.9%). There was a correlation between the log TVDT and patient age (R = 0.73), an inverse correlation between the log TVDT and MIB-1 index (r = -0.49), and an inverse correlation between the MIB-1 index and patient age (r = -0.61). A significant difference (p = 0.0001) was noted between the TVDT (1,106 days) in the 19 patients younger than 61 years of age and the TVDT (2566 days) in the 19 patients who were 61 years of age or older. There was also a significant difference (p = 0.0002) between the age (50.8 +/- 15.3 years) of the patients with rapidly growing tumors (TVDT < 1,836 days, 24 patients) and the age (69.1 +/- 7.6 years) of the patients with slowly growing tumors (TVDT> 1836 days, 14 patients). Other factors including the patients' sex, CS invasion, and intratumoral cyst formation did not affect the TVDT of residual NFPAs.

CONCLUSIONS

The tumor growth rate of residual NFPAs is strongly influenced by the patient's age. The TVDT in elderly patients is much longer than that previously reported. Treatment strategies that take into consideration the natural history of residual adenomas should be established especially in the elderly population.

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.

Comparison of endonasal endoscopic surgery and sublabial microsurgery for prolactinomas

BACKGROUND

Endonasal endoscopy is a promising minimally invasive surgery for the treatment of pituitary adenomas; it is also a good alternative to traditional sublabial microsurgery. In this study, we compared endoscopic surgery with microsurgery and evaluated both for their safety and effectiveness. We chose prolactinomas for study because their hormone and symptomatic changes facilitated the comparison.

METHODS

During the past five years, 44 randomized prolactinoma patients underwent pituitary adenomectomy. Group A (22 patients) underwent endonasal endoscopic surgery for prolactinomas. Group B (22 patients) underwent sublabial transsphenoidal microsurgery for prolactinomas.

RESULTS

In groups A and B, patients with prolactinoma exhibited significantly reduced postoperative prolactin levels, return of menstrual cycle, and relief of galactorrhea, (Wilcoxon signed rank test) (p < 0.001). But there were no statistically significant differences in the effectiveness of the procedures used in group A and group B. Visual improvement in cases of macroadenoma was satisfactory in both groups. Hospital stay in group A ranged from 2-5 days, with a mean of 3.2 days. Hospital stay in group B ranged from 4-8 days with a mean of 5.3 days. The hospital stay for group A patients was shorter (2.1 days) than for group B (Student t test, p < 0.05). The operative time was shorter by 1 hour in Group A (mean: 1.7 hours vs. mean: 2.7 hours, p < 0.05). There were fewer complications in group A (4.5%) than in group B (27%), p < 0.05.

CONCLUSIONS

The endoscopic era of pituitary surgery may be coming. Endonasal endoscopic surgery may have the same effectiveness as traditional microsurgery. However, endoscopic surgery may shorten hospital stay and operative time, and lead to fewer complications. It seems to be a good minimally invasive surgical technique for prolactinomas.

The history and evolution of transsphenoidal surgery

Initial attempts at transcranial approaches to the pituitary gland in the late 1800s and early 1900s resulted in a mortality rate that was generally considered prohibitive. Schloffer suggested the use of a transsphenoidal route as a safer, alternative approach to the sella turcica. He reported the first successful removal of a pituitary tumor via the transsphenoidal approach in 1906. His procedure underwent a number of modifications by interested surgeons, the culmination of which was A. E. Halstead's description in 1910 of a sublabial gingival incision for the initial stage of exposure. From 1910 to 1925, Cushing, combining a number of suggestions made by previous authors, refined the transsphenoidal approach and used it to operate on 231 pituitary tumors, with a mortality rate of 5.6%. As he developed increasing expertise with transcranial surgery, however, Cushing reduced his mortality rate to 4.5%. With the transcranial approach, he was able to verify suprasellar tumors and achieve better decompression of the optic apparatus, resulting in better recovery of vision and a lower recurrence rate. As a result he and most other neurosurgeons at the time abandoned the transnasal in favor of the transcranial approaches. Norman Dott, a visiting scholar who studied with Cushing in 1923, returned to Edinburgh, Scotland, and continued to use the transsphenoidal procedure while others pursued transcranial approaches. Dott introduced the procedure to Gerard Guiot, who published excellent results with the transsphenoidal approach and revived the interest of many physicians throughout Europe in the early 1960s. Jules Hardy, who used intraoperative fluoroscopy while learning the transsphenoidal approach from Guiot, then introduced the operating microscope to further refine the procedure; he thereby significantly improved its efficacy and decreased surgical morbidity. With the development of antibiotic drugs and modern microinstrumentation, the transsphenoidal approach became the preferred route for the removal of lesions that were confined to the sella turcica. The evolution of the transsphenoidal approaches and their current applications and modifications are discussed.

Outcome of transphenoidal surgery for acromegaly and its relationship to surgical experience

BACKGROUND

A number of surgical series have been reported on the treatment of acromegaly and their results vary widely. The acceptable definition of remission has changed in recent years and it is known, though in a small series, that growth hormone levels of > 5 mU/l are still associated with an increased mortality from the condition. We have analysed data at this centre and examined the outcome of transphenoidal surgery for acromegaly, compared our results with recently published series from other centres and also assessed factors which might effect outcome including whether there is any demonstrable effect of the experience of the surgeon on outcome.

PATIENTS AND METHODS

We have analysed data from all of our 139 patients in whom follow up data are available who have undergone initial transphenoidal surgery for acromegaly by one surgeon at this centre, between 1974 and 1995. Follow up was for a median of 5 years (range 1 month to 17 years).

RESULTS

67% of patients achieved the criterion for remission (mean GH < 5 mU/l). Success was related to tumour size and preoperative growth hormone values. Thus 91% of patients with microadenomas were in remission postoperatively compared to 46% of patients with macroadenomas. Analysis of the results according to the year of operation showed an improvement in success rates with time. More than 15 years ago, the success rate according to the growth hormone criteria set was 48% and the failure rate 52%. In contrast in the last 5 years analysed, the overall success rate was 74% with a failure rate of 26% (P < 0.04). The success rate for microadenomas was 50% initially, then remained 100%. The case mix was analysed and no change was found. We have also demonstrated an improvement in pituitary function (including normalization of preoperative elevated prolactin) with time so that pre 1981 16% of patients' pituitary function improved perioperatively but 10 years later this figure had risen to 34% (P < 0.03). There was no change over time in the development of pituitary hypofunction, complication rate or recurrence rate.

CONCLUSION

Surgical treatment is a safe and effective treatment for acromegaly and remains the first choice of treatment for most acromegalic patients. The results of this centre compare favourably with series from other centres. We have demonstrated improved results, both in terms of post operative growth hormone values and pituitary function tests with time and increasing neurosurgical experience. We conclude that outcome for the surgical treatment for acromegaly is best achieved with one surgeon specialising in pituitary surgery. Improved operative outcome thus achieved has major cost implications and avoids the necessity for consideration of postoperative radiotherapy and the use of expensive growth hormone suppressing drugs in the postoperative period.

Transsphenoidal microsurgery for growth hormone-secreting pituitary adenomas: initial outcome and long-term results

Treatment of acromegaly has long been recognized as necessary to relieve symptoms, halt progression of deformities, and decompress the sella turcica. More recently, treatment strategies have focused on decreasing GH levels to a point at which mortality rates normalize, thereby redefining previous concepts of a cure. No surgical series to date has investigated the long-term effect of treatment on mortality rates. We retrospectively reviewed 254 consecutive patients with acromegaly who underwent transsphenoidal microsurgery of GH-secreting adenomas between 1974-1992. Seventy-six percent of these patients had basal GH levels <5 ng/mL within 30 days of surgery, and 24% had persistent disease. Multivariate analysis revealed that higher stage, grade, and preoperative GH levels were all predictive of persistence (P < 0.01). Long-term follow-up was obtained on 129 of the patients in initial remission. Of these, 9 (7%) had disease recurrence and 120 remained in remission. The incidence of major postoperative complications was 8% (2% permanent diabetes insipidus, 2% cerebrospinal fluid leaks requiring surgery, 2% meningitis, and 2% hypopituitarism), with no mortality. In contrast to the 2.4- to 4.8-fold increased mortality among untreated acromegalics, the mortality rate among patients with posttherapy GH levels <5 ng/mL was equivalent to that of age- and sex-matched controls. Aggressive therapy to normalize GH levels should therefore be instituted at diagnosis.

Effect of surgery and radiotherapy on visual and endocrine function in nonfunctioning pituitary adenomas

The effect of surgery alone or followed by radiotherapy in recovering visual abnormalities, debulking tumor mass and restoring hormone impairments was evaluated in 84 patients with clinical nonfunctioning pituitary adenomas (NFPA) subjected to 1-10 yr follow-up. All patients underwent surgery via transsphenoidal (in 69) or transcranic-pterional approach (in 15). Radiotherapy was performed after surgery in 59 of 72 patients with incomplete tumor removal. The assessment of pituitary function was performed in all patients before and every 1-2 yr after surgery and/or radiotherapy. Radiological and ophthalmologic assessment was performed before and 3, 6 and 12 months after surgery, then yearly. At diagnosis, headache and visual disturbances occurred in 63 and 58 patients, respectively, while deficiency of GH, TSH, ACTH, FSH, LH and ADH was documented in 55, 7, 19 47 and 6 patients, respectively. After surgery, gonadal function recovered in 12 women, visual disturbances improved in 43 patients (15 regained normal vision), pituitary function improved in 8 of 62 patients, worsened in 34 patients. At MRI, complete tumor removal was documented in 12 of 84 patients. After surgery alone, tumor regrowth was observed in 7 patients between 3-7 yr. After radiotherapy, vision improved in 9, remained unchanged in 49 and worsened in 1 of 59 patients. After radiotherapy, tumor regrowth was documented in 9 patients between 2-12 yr and the prevalence of hypopituitarism raised from 28.8% to 92% after 1 and 10 yr. In conclusion, surgery alone is effective only in a minority of patients (14.3%) and radiotherapy causes hypopituitarism in rather the totality of patients after 10 yr. The prevalence of tumor regrowth was similar in irradiated ones (15%) and non irradiated patients (28%; chi(2), p = 0.4). Therefore, a careful radiological followup is suggested after surgery so that radiotherapy can be performed promptly on the basis of clinical data, tumor regrowth and/or invasiveness documented at histology.

Surgical management of pituitary adenomas

Surgical management of pituitary adenomas continues to be a safe and effective method, suitable for a large number of patients suffering from the effects of these lesions. Frequently surgery is just part of an overall programme that includes medical management and radiation therapy as well. It is important for the physicians and the patients to understand that surgery alone may not be totally successful, but that with careful follow-up and appropriate adjunctive management, patients with pituitary tumours may live normal lives, and may enjoy reversal of the endocrine and visual problems that had been caused by their tumours. Careful study of surgically managed patients has contributed to some of the advances that have occurred in the overall management of pituitary adenomas and in our understanding of their biology, pathophysiology and pathogenesis.

Tension pneumocephalus after transsphenoidal surgery: two case reports

In this paper, a brief information on factors taking role in intracranial air formation and tension pneumocephalus because of two cases epidural air formation and tension pneumocephalus following transsphenoidal operation is presented. Two cases were treated conservatively.

Perioperative management and surgical outcome of the acromegalic patient with sleep apnea

Sleep apnea is a rare complicating factor of acromegaly associated with a high risk of perioperative airway compromise and unclear response to transsphenoidal resection of the underlying pituitary tumor. We reviewed four acromegalic patients with sleep apnea and documented postoperative objective and subjective improvement of their sleep disorders. The pathogenesis of this disorder and safe perioperative airway management are discussed.

Recovery of visual and endocrine function following transsphenoidal surgery of large nonfunctioning pituitary adenomas

A series of 35 patients with non-functioning pituitary adenomas undergoing transsphenoidal surgery is presented. In most cases, the presenting symptoms were related to the mass effect of the tumor. There was no operative mortality. Before surgery, visual field defects were documented in 21 patients (60%). After surgery, excluding 3 patients with preoperative blindness, 28% regained normal vision and 67% showed variable improvement. Preoperatively, 24 patients (69%) had abnormal pituitary function, 24 (69%) had hypogonadism, 7 (20%) adrenal insufficiency, 8 (23%) hypothyroidism and 2 (6%) panhypopituitarism. After pituitary surgery, all but one patient with normal preoperative function retained it. Of the patients with hypopituitarism, 11 (46%) had variable improvement and 13 (54%) had persistent deficits. After surgery, 4 patients (57%) with adrenal insufficiency recovered normal adrenal function, 7 patients (29%) with hypogonadism recovered gonadal function and 1 patient (13%) with hypothyroidism recovered thyroid function. Prior to surgery, the presence of a normal or slightly elevated PRL and a rise in TSH after TRH and in LH after GnRH stimulation were of value in predicting possible recovery of pituitary function after surgery. These observations suggest the presence of viable pituitary tissue in these cases and point out that, in some instances, the mechanism of hypopituitarism may be compression of the portal circulation, rather than destruction of the normal pituitary gland.

Characterization of 24-hour growth hormone secretion in acromegaly: implications for diagnosis and therapy

OBJECTIVE

Early studies of acromegaly undertaken before the general availability of insulin-like growth factor I (IGF-I) assays have used arbitrary and varying growth hormone (GH) threshold levels for diagnosing and assessing outcome of treatment for this disease. We have undertaken a detailed study of GH secretion and its relationship to IGF-I levels to assess the usefulness of GH and IGF-I measurements in the assessment of acromegaly.

PATIENTS

Thirty acromegalic subjects (12 untreated and 16 previously treated) and 30 age and sex-matched normal subjects were studied.

MEASUREMENTS

Twenty-four-hour GH secretion was obtained from 20-minute sampling and serum IGF-I was measured. Comparisons were made of IGF-I, mean 24-hour GH concentration, and of the pulsatile and diurnal characteristics of GH secretion between the two groups.

RESULTS

IGF-I levels in untreated acromegaly were elevated and clearly separated from the normal range. Mean 24-hour GH concentrations in untreated and treated acromegalic subjects with elevated IGF-I (> 40 nmol/l) were greater than (P < 0.01), and showed good separation from, those of normal subjects only after age-matching. From the 24-hour profiles, nadir GH levels in normal subjects fell below the level of detectability while those in untreated acromegalic subjects did not. Pulse amplitude (P < 0.01), ratio of pulsatile to non-pulsatile GH release and the night to daytime GH ratio (P < 0.05) were significantly reduced in acromegaly. In the six patients who attained normal IGF-I levels after surgery, pulsatile characteristics remained abnormal in four. Mean 24-hour GH was significant related (r = 0.57) to IGF-I. A random GH concentration > 2.5 micrograms/l (5 mIU/l) has a sensitivity of 77% and specificity of 95% in identifying acromegalic patients who have biochemically active disease (elevated IGF-I) after treatment.

CONCLUSIONS

Patients with active acromegaly secrete more GH than age-matched normal controls. GH secretion in acromegaly is characterized by marked blunting of pulsatile secretion and, in contrast to normal subjects, the failure of GH to fall to undetectable levels at any time during the 24-hour day. IGF-I measurement is a more practical alternative in the diagnosis of acromegaly and in the assessment of therapeutic outcome. Since abnormalities of GH regulation may persist despite normalization of IGF-I, a distinction between remission and cure should be made. Detailed post-treatment evaluation of GH secretion is necessary to define the nature of underlying GH regulation and to evaluate the risk of disease recurrence.

Relationships between insulin-like growth factor-1 levels and growth hormone concentrations during diurnal profiles and following oral glucose in acromegaly

OBJECTIVE

The aim of this study was to refine the biochemical definition of disease activity in acromegaly by comparing serum growth hormone (GH) measurements during a 10-hour day profile with serum GH values during an oral glucose tolerance test.

DESIGN

Using plasma insulin-like growth factor-1 (IGF-1) levels as a measure of disease activity, serum GH data from a day profile and from an oral glucose tolerance test were compared.

PATIENTS

Thirty-five acromegalic patients were studied, 13 of whom had serum GH measured during a day profile and 22 during an oral glucose tolerance test. In addition, basal plasma IGF-1 levels were estimated in all acromegalic patients, and in 24 normal subjects.

MEASUREMENTS

Following acid-ethanol extraction of the plasma samples, IGF-1 levels were measured by radioimmunoassay using a polyclonal antibody. In a day profile, six to eight blood samples for serum GH estimation were taken at hourly intervals during the day; during an oral glucose tolerance test samples for serum GH estimation were taken in the fasting state and every 30 minutes for 2 hours and measured by a two-site IRMA for GH.

RESULTS

Ninety-four per cent of acromegalic patients with raised plasma IGF-1 levels had serum GH concentrations > 10 mU/l whilst 98% of acromegalic patients with plasma IGF-1 levels in the normal range had serum GH concentrations < 6 mU/l. A highly significant positive correlation was found between the mean serum GH concentrations (r = 0.67), the minimum serum GH concentration (r = 0.65) and the area under the GH curve (r = 0.66) estimated during an oral glucose tolerance test and plasma IGF-1 concentrations. The relations between identical indices of serum GH concentration measured during a day profile and plasma IGF-1 levels, although significant, show a less powerful correlation. The relation between serum GH and plasma IGF-1 levels describes a curvilinear model, plasma IGF-1 levels exhibiting a plateau at serum GH concentrations > 40 mU/l but maintaining a linear relationship with serum GH levels < 20 mU/l.

CONCLUSIONS

A highly significant correlation exists between plasma IGF-1 levels and various parameters of serum GH levels in acromegalic patients. Hormonal assessment of disease activity in acromegaly is more accurately reflected by the serum GH concentration during an oral glucose tolerance test rather than by the serum GH level during a day profile. Normalization of plasma IGF-1 levels is rarely achieved unless the mean serum GH level is reduced to < 6 mU/l.

Pituitary oncocytomas: clinical features, characteristics in cell culture, and treatment recommendations

To determine whether there are significant differences between oncocytomas and pituitary adenomas, we evaluated clinical features, treatment regimens and outcome in 23 males and 9 females (average age 64 years, range 43-81 years) with the histologic diagnosis of pure pituitary oncocytomas (> 95% oncocytes). Symptom duration was six to twelve months in 6 cases (19%) and more than one year in 19 cases (59%). Three patients presented with sudden onset of symptoms, and were found to have hemorrhage within their tumors. Visual loss (69%) and symptoms of hypopituitarism (44%) were the most common presenting complaints. Preoperative endocrine profiles revealed abnormalities in most cases, including pituitary insufficiency in 56% and hyperprolactinemia in 59%. The tumors were typically large at presentation; all but one had suprasellar extension. 28 patients underwent transsphenoidal tumor resections; 4 underwent subfrontal craniotomies. Gross dural invasion was found at surgery in 11 cases. At a mean followup of 31 months (range 2-68 months), recurrent tumor was identified in 4 patients (12.5%). Tumor size, dural invasion, preoperative endocrine profile, and postoperative radiotherapy did not correlate with recurrence. Among seven oncocytomas grown in culture, five demonstrated two distinct cell types consisting of oncocytes and typical adenoma cells, respectively. Oncocytomas often have a different clinical presentation than functional pituitary adenomas.

Transsphenoidal adenomectomy for growth hormone-secreting pituitary adenomas in acromegaly: outcome analysis and determinants of failure

The results of transsphenoidal adenomectomy for growth hormone (GH)-secreting pituitary adenomas in acromegaly performed over a 17-year period were analyzed retrospectively to determine which preoperative factors significantly influenced the long-term surgical outcome. These variables were then used to develop a logistic regression model to determine the probability of surgical failure. The series consisted of 103 patients. Long-term follow-up study (mean duration 102 +/- 64 months) was performed to derive outcome analysis and determinants of failure. Surgical control was defined as a long-term postoperative serum basal GH level of less than 5 micrograms/liter, a long-term postoperative serum somatomedin C (SM-C) level of less than 2.2 U/ml, and a favorable clinical response. Eighteen (17.5%) patients did not meet these criteria. The overall control rate by the GH criteria was 81.3% and by the SM-C criteria 76.2%. By multivariate logistic regression analysis, tumor stage was the strongest predictor of outcome (p < 0.05). The preoperative GH level, tumor grade, and preoperative SM-C level were significant univariate predictors (p < 0.05). There were statistically significant differences in mean preoperative GH and SM-C levels (p < 0.05, t-test) and tumor stage (p < 0.05, chi-squared test) between patients whose acromegaly was controlled by surgery and those whose acromegaly was not. Furthermore, estimates were derived of the probability of surgical failure based on preoperative GH level, preoperative SM-C level, and tumor grade and stage. The authors believe these findings will enhance clinical decision-making for neurosurgeons considering transsphenoidal microsurgery in patients with acromegaly.

Persistent or recurrent acromegaly. Long-term endocrinologic efficacy and neurologic safety of postsurgical radiation therapy

As in other clinics, pituitary surgery was definitive treatment in less than 50% of cases of acromegaly treated at one institution over several decades. From 1965 to 1989, 24 acromegalic patients who had noncurative pituitary surgery received radiation therapy at the National Institutes of Health, with a basal human growth hormone level of greater than 5 ng/ml as the criterion for active disease. Using megavoltage irradiation, more than 60% of these patients stabilized at a normal hormonal range, and the overwhelming majority had decreasing growth hormone levels with time. No major side effects of irradiation were encountered except panhypopituitarism of varying degrees. The authors evolved a policy of surgery as the first option, followed by irradiation for patients with postoperative growth hormone levels more than 5 ng/ml.

Proliferation in pituitary adenomas: measurement by MAb KI 67

The monoclonal antibody MAb KI 67 reacts with a nuclear antigen throughout the entire cell cycle and allows easy evaluation of proliferating tumour cells on routinely prepared smear and frozen sections. 120 pituitary adenomas were investigated by use of the monoclonal antibody KI 67 in a two-step avidin-biotin-peroxidase complex (ABC) technique. The KI 67 labelling index (LI) ranged in all adenomas from 0.2 to 4.6%. In 90 cases of transphenoidally operated adenomas the dura of the sella floor was investigated histologically. Adenomas with histologically proven dural infiltration showed a statistically significant higher KI 67 LI (p less than 0.001) compared to non-invasive adenomas.

Acromegaly in 14 cats

Acromegaly was diagnosed in 14 middle-aged to old cats of mixed breeding. Thirteen (93%) of the cats were male and one was female. The earliest clinical signs in the 14 cats included polyuria, polydipsia, polyphagia, all of which were associated with untreated diabetes mellitus. All developed severe insulin resistance within a few months; peak insulin dosages required to control severe hyperglycemia ranged from 20 to 130 U per day. Other clinical findings weeks to months after diagnosis included enlargement of one or more organs (e.g., liver, heart, kidneys, and tongue) (n = 14), cardiomyopathy (n = 13), increase in body size and weight gain (n = 8), nephropathy associated with azotemia and clinical signs of renal failure (n = 7), degenerative arthropathy (n = 6), and central nervous system signs (i.e., circling and seizures) caused by enlargement of the pituitary tumor (n = 2). The diagnosis of acromegaly was confirmed by demonstration of extremely high basal serum growth hormone concentrations (22 to 131 micrograms/l) in all cats. Computerized tomography disclosed a mass in the region of the pituitary gland and hypothalamus in five of the six cats in which it was performed. Two cats were treated by cobalt radiotherapy followed by administration of a somatostatin analogue (octreotide), whereas two cats were treated with octreotide alone. Treatment had little to no effect in decreasing serum GH concentrations in any of the cats. Eleven of the 14 cats were euthanized or died four to 42 months (median survival time, 20.5 months) after the onset of acromegaly because of renal failure (n = 2), congestive heart failure (n = 1), concomitant renal failure and congestive heart failure (n = 3), progressive neurologic signs (n = 2), persistent anorexia and lethargy of unknown cause (n = 1), the owner's unwillingness to treat the diabetes mellitus (n = 1), or unknown causes (n = 1). Results of necropsy examination in ten cats revealed a large pituitary acidophil adenoma (n = 10), marked left ventricular and septal hypertrophy (n = 7), dilated cardiomyopathy (n = 1), arthropathy affecting the shoulder, elbow, or stifle (n = 5), and glomerulopathy characterized by expansion of the mesangial matrix and variable periglomerular fibrosis (n = 10).

Evaluation of selective transsphenoidal adenomectomy by endocrinological testing and somatomedin-C measurement in acromegaly

A series of 29 previously untreated patients with acromegaly underwent transsphenoidal adenomectomy. Pre- and postoperative evaluation consisted of measuring growth hormone (GH) secretory dynamics during an oral glucose tolerance test (OGTT), the insulin hypoglycemia test, and the thyrotropin- and gonadotropin-releasing hormone (TRH/GnRH) test, and by obtaining the basal somatomedin-C level. After surgery, clinical and biochemical amelioration was achieved in all but two patients. In the whole group, basal GH and somatomedin-C levels decreased from a mean (+/- standard error of the mean) of 52.3 +/- 12.7 to 11.1 +/- 6.3 ng/ml and from 7.6 +/- 0.7 to 2.5 +/- 0.5 U/ml, respectively. Application of different criteria of cure revealed that 19 patients (66%) had basal GH levels below 5 ng/ml, 17 patients (59%) had normal somatomedin-C values, 16 patients (55%) had complete GH suppression (less than 1 ng/ml) during OGTT, and 13 patients (45%) met the above-mentioned criteria with disappearance of the paradoxical GH response to TRH/GnRH test. Evaluation of GH secretion by insulin hypoglycemia testing was useless in assessing the outcome after neurosurgery. When only patients with a normal somatomedin-C level and complete GH suppressibility during OGTT were considered "cured," the main favorable prognostic factor was intrasellar tumor localization, since 15 (75%) of 20 patients were "cured," as opposed to only one (11%) of nine with extrasellar extension of the adenoma. During the follow-up period, no tumor recurrence was detected in any of the "cured" patients. In these subjects somatomedin-C levels remained stable in all except two patients, who showed a slow increase within the normal range of somatomedin-C concentration. These data confirm that transsphenoidal surgery is the most effective form of treatment in previously untreated acromegalic patients and that normalization of somatomedin-C levels reflects normal GH secretion. Measurement of somatomedin-C could replace more extensive endocrinological testing during monitoring of treated acromegalic patients.

Role of transsphenoidal operation in the management of pituitary adenomas with suprasellar extension

59 consecutive patients with suprasellar extending pituitary adenomas were operated on by the transsphenoidal approach. The suprasellar tumour extension was in 30 cases stage A (Hardy-Wilson), in 18 stage B and in 11 stage C. 14 patients were above 65 years of age and in this latter group 9 cases had large tumours (B or C). 78% of endocrinologically active tumours did not reach the chiasm (stage A) whereas 72% of functionless adenomas compressed the chiasm or grossly the third ventricle. Visual field defects and loss of visual acuity was both present in roughly 90% of stage B and C tumours. Radical surgical removal with regard to suprasellar extension was possible in all but 6 cases. Four of these patients had tumour remnants large enough to require removal by a second intracranial operation. No patient developed visual deterioration post-operatively. Pre-operative visual dysfunction was normalized or markedly improved in more than 90% of the cases. Failure to normalize vision was closely linked to the presence of pale optic discs. Pre-operative hypersecretion was normalized in 70% of the cases. Addition of permanent pituitary insufficiency occurred in three patients.

Surgical correction of the acromegalic face. A one stage procedure with a team approach

The features of acromegaly are presented with special reference to facial deformity. A one-stage procedure with careful pre-operative planning is advocated. The operating team is composed of a plastic surgeon and an oral surgeon. The frontal protrusion is corrected by osteotomy, the vertical and anteroposterior facial disproportion by bimaxillary procedures, the nasal deformity by rhinoplasty or skull bone grafting, and the macroglossia by tongue resection. This results in an improvement of the patient's psyche and frequently improvement in speech.

Results of transsphenoidal microsurgery for growth hormone-secreting pituitary adenoma in a series of 214 patients

Of 214 patients with acromegaly who underwent transsphenoidal microsurgical resection of a pituitary adenoma, 54% had growth hormone (GH) levels below 5 ng/ml and 74% had levels less than 10 ng/ml immediately after surgery. Among the 174 patients who could be contacted for long-term follow-up review (average duration 76 months), most recent GH determinations were available for 165. Of these 165 patients, 131 (79.4%) have a GH level less than 5 ng/ml and 153 (92.7%) have a level below 10 ng/ml; these represent 75.3% and 87.9%, respectively, of the total 174 patients reviewed. Fifty-two patients received postoperative radiation therapy. Nine patients underwent reoperation. There were five cases of tumor recurrence following an apparent surgical cure (4.3%), nine new instances of anterior pituitary hypofunction (5%), and five failures of multimodality therapy (2.3%). There were no perioperative deaths, five cases of cerebrospinal fluid leak requiring surgical repair (2.2%), and four cases of postoperative meningitis (1.8%). Permanent diabetes insipidus did not occur. Two of 52 patients who were irradiated postoperatively had severe complications; 23 (54.8%) of 42 patients who were available for follow-up evaluation had developed panhypopituitarism; and eight (19%) of 42 had normal pituitary function an average of 44 months postirradiation.

Criteria for the cure of acromegaly: comparison between basal growth hormone and somatomedin C plasma concentrations in active and non-active acromegalic patients

Fasting plasma growth hormone (GH) and somatomedin C (SmC) levels were compared as criteria for the cure of acromegaly in 7 untreated and 16 treated acromegalic patients studied 1 to 16 yr after pituitary surgery and/or radiotherapy. The patients without active disease presented a significant correlation between GH and SmC. Only when basal GH was lower than 2.5 ng/ml were SmC values within the normal range. The subjects with active acromegaly (both treated and untreated) presenting GH higher than 5 ng/ml did not show any correlation between GH and SmC levels.

Investigation of the criteria for assessing the outcome of treatment in acromegaly

The outcome of treatment in acromegaly is usually assessed by measuring plasma concentrations of growth hormone (GH)--either basal spontaneous levels or during hyperglycaemia. There is no consensus on how cure should be defined. Many studies have considered basal plasma growth hormone concentrations below 20 mU/l (10 ng/ml) as proof of cure, although some recent studies have applied lower values. At present a limit of 10 mU/l (5 ng/ml) seems to be accepted as evidence of cure. We have studied 28 acromegalic patients after transsphenoidal adenomectomy. Plasma GH concentrations (basal and during hyperglycaemia) as well as plasma somatomedin C (SMC) concentrations were measured and compared to the clinical symptoms. There was a close correlation between plasma GH and SMC concentrations (except when plasma GH levels were low) and between the clinical assessment and SMC concentrations. Very low plasma GH levels (less than 1 mU/l or 0.5 ng/ml) were associated with normal SMC values and clinical cure, high GH levels (greater than 10 mU/l or 5 ng/ml) with elevated SMC levels and persisting acromegaly. Moderately elevated plasma GH concentrations (1.9-9.6 mU/l) did not allow any conclusions on the outcome of treatment as assessed from SMC determinations and clinical evaluation. It is concluded that the usual criteria for cure in acromegaly may not be sufficiently strict.

Long-term results in transsphenoidal removal of nonfunctioning pituitary adenomas

Little has been written about the long-term results of transsphenoidal treatment for clinically nonfunctioning pituitary adenomas. The records of 100 patients who had undergone a transsphenoidal procedure for excision of such tumors were reviewed. Immunocytology for pituitary hormones was performed in all cases. The group consisted predominantly of null-cell adenomas, although a small number of prolactinomas and gonadotropic tumors were found. The mean diameter of the tumors at the time of detection was slightly more than 2 cm. In most cases, the presenting symptoms were due to the mass effect of the tumor (that is, visual symptoms in 72 patients, hypopituitarism in 61, headache in 36, and cranial nerve disturbance other than visual loss in 10). Radiation therapy was recommended for patients in whom subtotal removal of the adenoma was expected. Six patients developed symptomatic tumor recurrence, and 10 patients demonstrated radiographic recurrence during the 48 to 100 months (mean 73.4 months) of follow-up observation. Only three of 10 deaths during the follow-up period were due to pituitary disease or treatment.