ANZ J. Surg.

2003;

73

: 850–852

CONTINUING MEDICAL EDUCATION

CONTINUING MEDICAL EDUCATION

ADRENAL SURGERY: AN UPDATE

C

HRISTOPHER

P. B

AMBACH

Department of Endocrinology, Royal North Shore Hospital, New South Wales, Australia

Key words: adrenalectomy, laparoscopy.

Abbreviations

: ACTH, adrenocorticotropic hormone; CT, computed tomography; MEN–2, multiple endocrine neoplasia;MIBG, methyliodobenzylguanidine; PA, plasma aldosterone; PRA, plasma renin activity.

INTRODUCTION

During the last 20 years most endocrine surgical units have expe-rienced a progressive increase in the numbers of patients under-going adrenalectomy.

1

A marked change has also occurred in therelative numbers being operated on for primary hyperaldos-teronism (Conn’s Syndrome), phaeochromocytoma, hypercorti-solism (Cushing’s Syndrome), malignancy, incidentaloma and astherapy for advanced breast cancer. These changes have occurredbecause of more frequent investigation into the treatable causesof hypertension; the increased accuracy, availability and use ofscans and other modalities to examine the structure and functionof the adrenal glands and the introduction of laparoscopic adrena-lectomy. Laparoscopic adrenalectomy has been rapidly acceptedamong physicians and surgeons as a significant advance in themanagement of hypertension. The present article will look at theinvestigation and management of these common indications foradrenalectomy and discuss the laparoscopic surgical method.

CONN’S SYNDROME

In 1955 Conn described a new syndrome of hypokalaemia,hypernatraemia and excess urinary aldosterone in patients withhypertension.

2

He subsequently proposed that up to 20% ofpeople with essential hypertension might have the syndrome.

3

Primary hyperaldosteronism is suggested by an elevated plasmaaldosterone (PA) to plasma renin activity (PRA) ratio. This ratiohas been used by various investigators to identify normokalaemicprimary hyperaldosteronism in up to 15% of selected groups ofhypertensive patients.

4,5

While the incidence in the general popu-lation of hypertensive patients is likely to be lower

6

there is thepotential to benefit large numbers of patients with early diagnosisand management. In our unit a PA : PRA of

≥

40, an elevatedurinary aldosterone level with appropriate intake and output ofsodium over 24 h, lateralization of markedly elevated aldosteronesecretion on selective adrenal venous sampling, and usually anidentifiable tumour in one adrenal gland on computed tomog-raphy (CT) scan would lead to a recommendation for laparo-scopic adrenalectomy in medically suitable patients. Using thesecriteria, 30–40% of patients will remain normokalaemic and

normotensive on no medication postsurgery. A similar percent-age will have significant improvement in blood pressure controlbut need some medication.

7,8

The pathology found in the adrenalgland is usually a small (10–20 mm) adenoma, which is ideallysuited to the laparoscopic method that can be performed withvery low morbidity, virtually no mortality and thus a very highlevel of patient acceptance.

PHAEOCHROMOCYTOMA

Phaeochromocytoma is the most interesting and challenging ofthe adrenal conditions. It is a rare tumour that can occur either asa sporadic event or as part of a recognized genetic abnormality,in which case bilateral involvement is a possibility. Geneticabnormalities include the multiple endocrine neoplasia (MEN–2)syndrome, the phacomatoses and familial extra adrenal tumour.

9

The presentation and natural history is variable. Phaeochromo-cytoma might be detected during investigation of hypertension orpresent dramatically with life-threatening symptoms – uncon-trolled hypertension and acute heart failure. Occasional patientswill present because of bleeding from the tumour. About 5% ofphaeochromocytomas will behave in a malignant fashion.

Diagnosis is made by estimation of plasma and urinary cata-cholamines and their metabolites, a CT scan and a nuclearmedicine scan with methyliodobenzylguanidine (MIBG). This isconsidered important to confirm the diagnosis, the precise loca-tion of the tumour and to exclude multiple or metastatic lesions.

C. P. Bambach

MB BS, MD, FRACS.

Correspondence: Dr Christopher P. Bambach, North Shore Medical Centre,66 Pacific Highway, St Leonards, NSW 2065, Australia.Email: bamfam@bigpond.com

Accepted for publication 20 May 2003.

Author:

Dr Christopher P. Bambach, MB BS, MD (SYD), FRACS.

ADRENAL SURGERY: AN UPDATE 851

Following diagnosis, careful medical management is thenrequired to control the effect of excessive catecholamine secre-tion using a combination of

α

- and

β

-blockade. Treatment shouldbe given for 2–3 weeks prior to surgery to prevent intraoperativehypertensive crises. Anaesthesia should be supervised by anexperienced anaesthetist, who should monitor urinary output,arterial blood pressure, central venous pressure and, if available,transoesophageal echocardiography.

10

Laparoscopic adrenalec-tomy is the method of choice for tumours of up to 60–70 mm.Above this size laparotomy will often be required because oftumour vascularity. Laparoscopic vascular staplers are oftenrequired to control the large supplying vessels. For 24 h post-operative, haemodynamic instability might be present and requirea period of careful monitoring in an intensive care setting. Thepathology report needs careful examination and appropriateadvice should be given to the patient regarding the long-termrisks of malignancy based on tumour size, mitoses, tumour necro-sis and capsular invasion. Catecholamines should be measuredpostoperatively and at follow up.

HYPERCORTISOLISM

Excessive cortisol secretion might be caused by primary adenoma,ectopic adrenocorticotropic hormone (ACTH) production, adrenalhyperplasia and adrenal adenoma or carcinoma. Symptoms andsigns can be subtle or associated with a full-blown Cushing’spicture with hypertension, muscle weakness, trunkal obesity,hirsutism, abdominal striae, acne and menstrual irregularity.

Surgical management is determined by the underlying cause.Bilateral adrenalectomy, laparoscopic or open, is offered topatients with Cushing’s disease who have failed pituitary abla-tion, those with macro or micro nodular hyperplasia and occa-sionally those with ectopic ACTH production.

11

Unilateraladrenalectomy is indicated for a cortical adenoma or carcinoma.In general, the laparoscopic method is preferred for all pathologyexcept larger (>60 mm) cancers.

1,7

The important principle is tocompletely remove the gland with a margin of normal tissue toavoid future recurrence. Large adreno-cortical carcinomas arevery aggressive and are associated with a poor prognosis; how-ever, aggressive removal of all macroscopic tumour via laparot-omy is warranted.

12

INCIDENTALOMA

The incidental or accidental discovery of a tumour in an adrenalgland is a relatively common occurrence nowadays because ofthe widespread use of CT scanning. Once found, appropriateinvestigations are required to: firstly exclude hyperfunction andsecondly to estimate the likely histology and malignant potentialof the lesion. Serial examination of blood pressure, serum elec-trolytes, cortisol, aldosterone and catacholamines should bedetermined, as described previously, after taking a careful historyand performing a thorough physical examination looking for thestigmata of adrenal disease. Adrenal CT scans should be donewith close cuts and then interpreted by a radiologist with specialexpertise in this area. If the CT is consistent with an adrenal mye-lolipoma, cyst or haemorrhage then no further investigation isrequired. Magnetic resonance imaging might provide additionaluseful information. Tumours that are hyperfunctioning, morpho-logically suspicious, greater than 30 mm in size or shown to haveincreased in size on serial CT scans should be removed – usuallyby laparoscopic adrenalectomy.

SURGICAL TECHNIQUE

Laparoscopic adrenalectomy was first described in 1992

13

andhas become the method of choice for resection of benign adrenalpathology

14

and smaller malignant lesions. While the operationcan be carried out using either a transperitoneal or retroperitonealapproach, I prefer the transperitoneal approach. Relative con-traindications to the laparoscopic method include: malignantinvasion of adjacent tissue, coagulopathy, severe cardiopulmo-nary disease likely to be compromised by pneumoperitoneum,and severe intra-abdominal adhesions.

14

Careful preoperative medical preparation, thrombo-emboicprophylaxis, adequate monitoring by an expert anaesthetist andselective postoperative intensive care observation are required,as previously described. The patient is secured with tape onto abeanbag in a 60

°

lateral position with the involved adrenaluppermost. A 10–12-mm Hasson port is placed above andlateral to the umbilicus through the rectus sheath. Three furtherports are placed to the right and two to the left. The additionalright port admits the ‘soft’ inflatable liver retractor. The har-monic scalpel is considered an invaluable tool for most of thedissection. On the left the splenic flexure of colon and spleen ismobilized and falls medially, the tail of the pancreas is visual-ized and the adrenal is identified deep in the sulcus medial tothe left kidney. The main vascular attachments are via the inte-rior phrenic and left renal vessels, which are ligated with clips.On the right the liver and gallbladder are retracted superiorly,the posterior fascia is divided and the anterior surface of theinferior venacava (IVC) is identified. The medial aspect of theadrenal is dissected and once clip ligation of the short, wideadrenal vein is accomplished, removal should be readily feas-ible. Occasionally a vascular stapler is required for this vessel.Meticulous haemostasis is required at all times. The gland itselfshould never be grasped by an instrument. Dissection shouldinclude a margin of fatty tissue all around and the gland shouldbe delivered in an endopouch. High resolution camera andvideo equipment, with both 0 and 30

°

scopes and a high flowinsufflator, are essential. Three hours should be allocated forperforming the procedure and a learning curve of approximately25 cases should be anticipated.

7

Laparoscopic adrenalectomy has been reported in well over1000 instances in the literature of many units. It can be performedwith a very low morbidity and mortality, and has a high level ofpatient acceptance. The question now has become ‘when is thelaparoscopic method not the preferred surgical approach?’.

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