0021-972X/99/$03.00/0
The Journal of Clinical Endocrinology & Metabolism
Copyright © 1999 by The Endocrine Society
Vol. 84, No. 12
Printed in U.S.A.
COMMENTS
Tension Pneumocranium, a Rare Complication of
Transsphenoidal Pituitary Surgery: Mayo Clinic
Experience 1976 –1998
ANNA M. SAWKA, JAROSLAW P. ANISZEWSKI, WILLIAM F. YOUNG, JR.,
TODD B. NIPPOLDT, PAULINO YANEZ, AND MICHAEL J. EBERSOLD
Division of Endocrinology, Metabolism and Nutrition, Internal Medicine (A.M.S., J.P.A., W.F.Y.,
T.B.N.), Division of Hypertension and Internal Medicine (W.F.Y.), Department of Neurosurgery (P.Y.,
M.J.E.), Mayo Clinic, Mayo Foundation, Rochester, Minnesota 55902
ABSTRACT
We describe four cases of symptomatic pneumocranium, a rare, potentially life-threatening complication of transsphenoidal pituitary surgery. Symptomatic pneumocranium manifested as impaired mental status, headaches, and grand mal seizures, early in the postoperative course
after transsphenoidal pituitary surgery. Furthermore, a Cushing response, including systemic hypertension and bradycardia (secondary to
intracranial hypertension) was seen, which has not been previously
described in association with symptomatic pneumocranium. We describe
a previously unreported risk factor for tension pneumocranium, un-
P
NEUMOCRANIUM (pneumocephalus) has been associated with various conditions such as: basilar skull
fracture, facial trauma, neurosurgery, paranasal sinus surgery, mask or nasal continuous positive-airway pressure,
and even lumbar puncture (1–5). Pneumocranium usually
resolves, as air is gradually absorbed, without neurologic
sequelae or need for treatment (6).
Symptomatic pneumocranium after transsphenoidal pituitary surgery is rare (1, 4 – 8). Potential complications include
tension pneumocranium (neurologic dysfunction with increased intracranial pressure) and meningitis, both of which
can be fatal (4, 5). Tension pneumocranium may be manifested clinically by decreased level of consciousness, headache, seizures, decreased visual acuity, visual field defects, or
papilledema (1, 5, 6 – 8). Treatments of pneumocranium include observation, prophylactic therapy with systemically
administered antibiotics, insertion of intracranial drains, and
repair or packing of the floor of the sella (1, 5, 6 – 8). Symptoms of tension pneumocranium may resolve rapidly after
venting and draining the air pocket, repair of the sella, or
both (1, 5, 6). We describe four cases of symptomatic pneumocranium after transsphenoidal surgery, and possible
associations.
Received July 21, 1999. Revision received August 17, 1999. Accepted
August 24, 1999.
Address correspondence and requests for reprints to: William F.
Young, Jr., MD, Division of Endocrinology, Metabolism, Nutrition and
Internal Medicine, Mayo Clinic, 200 First Street Southwest, Rochester,
Minnesota 55905.
treated obstructive sleep apnea. Other factors predisposing to tension
pneumocranium in our patients included: cerebrospinal fluid leaks, postoperative positive-pressure mask ventilation, large pituitary tumors,
and intraoperative lumbar drainage catheters. Surgical drainage of the
pneumocranium and repair of any coexistent cerebrospinal fluid leak
markedly improved neurologic status.
Symptomatic pneumocranium occurring early in the postoperative
course after transsphenoidal pituitary surgery is rare, but prompt
recognition and treatment of this condition can be life-saving. (J Clin
Encocrinol Metab 84: 4731– 4734, 1999)
Subjects and Methods
We reviewed the medical records of patients encountered at Mayo
Clinic Rochester from 1976 to 1998. Cases eligible for analysis were
identified by computer-based cross-index codes for pneumocephalus or
pneumocranium. Four cases were identified of tension pneumocranium
after transsphenoidal surgery.
Results
This condition is extremely rare. Over 2500 transsphenoidal surgeries were performed at the Mayo Clinic from
1976 to1998, 4 of which were complicated by tension pneumocranium. All 4 patients presented with sudden onset of
decreased level of consciousness in the days after transsphenoidal surgery. Headaches, seizures, and cranial
nerve palsies were present to various degrees. A Cushing
response, consisting of systemic hypertension with or
without bradycardia (secondary to intracranial hypertension) was also seen, which has not previously been reported in association with pneumocranium. CSF leakage
was present in 2 cases, both of which required formal
repair. We describe obstructive sleep apnea (OSA) as a
possible risk factor for symptomatic pneumocranium after
transsphenoidal surgery (seen in 2 cases), which has not
been previously published. Furthermore, positive-pressure bag-valve mask ventilation postoperatively was associated with tension pneumocranium in 1 case. Prompt
drainage of intracranial air (and subsequent repair of CSF
leak, if present) resulted in rapid improvement of neurologic status.
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JCE & M • 1999
Vol 84 • No 12
Case Reports
Case 1
A 74-yr-old man presented with clinical acromegaly, confirmed with
a basal GH level of 74 mg/L (which failed to suppress on oral glucose
tolerance testing), and insulin-like growth factor-1 level of 468 ng/mL
(normal, ,100). He also had untreated OSA (confirmed by consultation
in a sleep disorders center).
The patient underwent transsphenoidal excision of a 1-cm macroadenoma with an unremarkable intraoperative course. On postoperative
day 1, the patient became hypertensive and extremely lethargic. A computed tomographic (CT) scan revealed a large subdural air collection,
consistent with the diagnosis of tension pneumocranium (Fig. 1A). A
right frontal subdural drain was placed via a right frontal burr hole,
immediately releasing a small gush of air. The drain was in place for 6
days, and the patient recovered completely without neurologic sequelae.
Blood pressure normalized, and subdural air gradually resorbed (Fig.
1B).
Case 2
A 56-yr-old woman presented with ACTH-dependent Cushing syndrome. Head magnetic resonance scan showed shift of the pituitary stalk
to the left. OSA was newly diagnosed from symptoms and abnormal
findings on overnight oximetry.
Transsphenoidal dissection was performed without difficulty; however, no discrete pituitary adenoma was identified, and a hypophysectomy was performed. Biochemical cure of the Cushing syndrome was
confirmed postoperatively.
Starting on postoperative day 1, the patient complained of severe
occipital headaches, and nasal drip of CSF was noted. Lethargy, hypertension (up to 180/60 mm Hg), and a generalized tonic-clonic seizure
were noted on postoperative day 3; iv phenytoin and empiric antibiotics
were given. Head CT showed bifrontal pneumocranium (Fig. 2A). A
right frontal subdural drain was placed, and pneumocranium gradually
resolved (Fig. 2B). Blood pressure normalized. The CSF leak was surgically repaired on postoperative day 8; and thereafter, mental status
markedly improved, and no long-term neurologic deficits were noted.
Case 3
A 20-yr-old man presented with headaches, lethargy, and hypogonadotropic hypogonadism. A CT scan of the head showed a large suprasellar calcified mass that extended superiorly and displaced the brain
stem posteriorly.
Transsphenoidal exploration of the sella was performed, and the
large intrasellar component of a craniopharyngioma was removed. A
lumbar spinal catheter was placed intraoperatively. The patient returned
to the operating room on postoperative day 7 for a right frontal craniotomy and gross total removal of his craniopharyngioma. Another intraoperative lumbar spinal drain was inserted. The patient had no new
neurologic deficits postoperatively.
Three days after his craniotomy (10 days after transsphenoidal surgery), the patient developed a left lower lobe nosocomial pneumonia. He
was treated with broad-spectrum antibiotics and aggressive chest physiotherapy, including intermittent positive-pressure ventilation via bagvalve mask. Nasal-tracheal suctioning was strictly avoided.
On day 5 after his craniotomy, the patient became unresponsive, with
dilated pupils. A CT scan of the brain showed a large tension pneumocranium displacing the brainstem posteriorly. A right ventricular
needle was used to release air under pressure and resulted in mild
improvement in level of consciousness. A cerebrospinal fluid (CSF) leak
was then repaired transsphenoidally. Neurologic status markedly improved. No long-term neurologic deficits were attributed to tension
pneumocranium.
Case 4
A 56-yr-old male was transferred to the Mayo Clinic with a huge
nonfunctioning pituitary tumor. He had been in a state of coma for 16
days, and a ventriculoatrial shunt had been placed for obstructive hydrocephalus in the weeks preceding transfer. A CT scan of the head
showed a large enhancing mass filling the sella and suprasellar region
FIG. 1. Case 1. A, CT scan of the head, showing tension pneumocranium; B, CT scan of the head, 2 days after drainage of tension pneumocranium.
into the anterior third ventricle, which obstructed the foramen of Munro,
producing obstructive hydrocephalus. Laboratory investigations were
significant for hypogonadotropic hypogonadism.
The patient was given high-dose dexamethasone and underwent
urgent transsphenoidal exploration of the sella. A lumbar spinal needle
was inserted intraoperatively. Massive amounts of a nonfunctioning
pituitary adenoma (5– 6 cm in diameter) were removed. A small CSF leak
occurred intraoperatively. Postoperatively, the patient awakened and
had no gross motor deficits. Bilateral temporal hemianopsia was present.
On postoperative day 10, the patient became extremely lethargic. A
CT scan of the head showed large air collections in the extracerebral
COMMENTS
4733
spaces, with collapse of the brain. Drilling bilateral frontal burr holes and
venting of subdural air with bilateral Jackson-Pratt drains were done
emergently. Level of consciousness improved dramatically. The patient
was dismissed home within a few weeks.
The patient subsequently underwent external beam radiation therapy. However, 6 months after the original transsphenoidal surgery,
symptomatic recurrence of the pituitary tumor with obstruction of the
third ventricle was noted. Repeat transsphenoidal exploration with intraoperative insertion of a lumbar CSF drain was performed.
Clinical course was unremarkable until postoperative day 4, when the
patient suddenly became lethargic, hypertensive (184/110 mm Hg), and
bradycardic (pulse 52 bpm). An emergent CT scan of the head showed
a large amount of air in the third and fourth ventricles. Because the
patient’s level of consciousness seemed to be improving, transsphenoidal reexploration and drainage of intracranial air were deferred. After
a month in hospital, the patient was dismissed home and completed
further radiation therapy as an outpatient.
Discussion
Tension pneumocranium occurs when air enters the cranium but cannot exit, likely secondary to a one-way valve
mechanism. The result is increased intracranial pressure.
After transsphenoidal surgery, the intracranial contents are
in direct continuity with the nasopharynx, providing a potential route for such a one-way valve.
We have noted an association of OSA with symptomatic
pneumocranium following transsphenoidal surgery. OSA is
common in obesity and acromegaly (9 –11). Recurrent upper
airway narrowing or closure during sleep and frequent recurrent elevations in CSF pressure characterize OSA (12, 13).
Such dynamic pressure changes could result in pneumocranium following transsphenoidal surgery. Similarly, positivepressure mask ventilation could insufflate air into the
cranium.
The insertion of lumbar CSF drains has rarely been reported as a cause of pneumocranium (8, 14). Perioperative
CSF drainage, either from a shunt, a leak, or a spinal drainage
catheter could predispose to air entering the diaphragm sella
opening from the transsphenoidal surgery. Resection of a
huge sellar mass may also result in decreased CSF pressure,
predisposing to air accumulation.
In terms of clinical signs of tension pneumocranium, systemic hypertension and bradycardia have not previously
been described in association with intracranial air. Both of
these signs are part of the Cushing response to increased
intracranial pressure (15). The most sensitive sign of tension
pneumocranium in our case series was change in mental
status. Headache was an inconsistent finding, as were seizures and cranial nerve deficits.
Conclusions
FIG. 2. Case 2. A, CT scan of the head showing tension pneumocranium. B, CT scan of the head 4 days after drainage of pneumocranium.
Symptomatic pneumocranium is a rare but life-threatening complication of transsphenoidal pituitary surgery. We
have described several risk factors including OSA, positivepressure mask ventilation, resection of large sellar masses,
postoperative CSF leak, and possibly insertion of a lumbar
subarachnoid drain intraoperatively. Clinical symptoms and
signs of this condition include: altered mental status, headaches, seizures, cranial nerve palsies, hypertension, and bradycardia (as part of the Cushing response). In this age of
short hospital stays, patients and their families should be
alerted to call for medical assistance if such symptoms occur
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in the days following transsphenoidal surgery. Long-term
outcome is generally favorable if this condition is recognized
and treated promptly.
8.
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