- The study examines whether the pre-operative use of a lumbar drain reduces post-operative cerebrospinal fluid leaks in patients undergoing acoustic neuroma resection. - 282 patients were included in the study, with 220 receiving a pre-operative lumbar drain and 62 not receiving one. No significant difference was found in CSF leak rates between the two groups. - While CSF leaks are a common complication, the routine use of pre-operative lumbar drains is not recommended due to the 5.3% complication rate associated with lumbar drain use and no evidence that it decreases CSF leak rates.

1. Preoperative Lumbar Drain Use during Acoustic
Neuroma Surgery and Effect on CSF Leak Incidence
Matthew G. Crowson, MD1; Calhoun D. Cunningham III, MD1; Helen Moses, MD1; Ali Zomorodi, MD2;David Kaylie, MD, MS1
Duke University Medical Center, 1Division of Otolaryngology-HNS, 2Division of Neurosurgery
INTRODUCTION DISCUSSIONRESULTS
Table 1. Descriptive statistics of patient demographics and tumor
factors.
ABSTRACT
METHODS AND MATERIALS
CONCLUSIONS
REFERENCES
CONTACT
Objective: To determine if preoperative
lumbar drain (LD) use reduces the
incidence of postoperative
cerebrospinal fluid (CSF) leak in patients
undergoing acoustic neuroma resection.
Study design: Retrospective Review.
Setting: Tertiary Care Hospital
Patients: 282 patients presenting for
primary acoustic neuroma resection
between 2005-2014.
Interventions: Clinical record review of
tumor characteristics, imaging,
procedures, patient outcomes, CSF
leak incidence, and postoperative
complications.
Main outcome measures: CSF leak
frequency, LD complications, analysis of
patient demographics and diagnosis,
tumor size, surgical approach, and length
of stay.
Results: 282 patients had a mean tumor
size of 19.1 mm +/- 10.2 mm. 29 (10.3%)
patients developed a postoperative CSF
leak. 220 patients (78.0%) received a
preoperative LD, and 20 (9.1%) developed
a CSF leak. 62 (22.0%) patients did not
receive a preoperative LD, and 9 (14.5%)
developed a CSF leak. No significant
difference in CSF leak frequency observed
with use versus no use of a LD (p > 0.05).
15 (5.3%) patients with a LD placed had a
complication related to the LD. No
significant difference in CSF leak
frequency was observed with patient age,
Neurofibromatosis Type-2 diagnosis,
tumor size or sidedness.
Conclusions: Postoperative CSF leaks are
amongst the most common complications
of acoustic neuroma microsurgery. No
formal guidelines exist for the elective
placement of a preoperative LD to lower
the incidence of CSF leaks. Our reported
CSF leak incidence with preoperative LD
placement is not significantly lower than
without LD use, and there is a significant
complication rate associated with LD use.
313 patients underwent resection for an acoustic
neuroma. 282 patients were included in the analysis, and
31 excluded for prior resection attempt, or if they had a
pre-operative external ventricular drain (EVD) placement.
220 (78.0%) patients received a pre-operative lumbar drain
(LD) placed prior to acoustic neuroma resection (Table 3).
Fifteen patients (5.32%) had a complication related to their
LD. Complications included LD falling out early (5), LD leak
(3), over-draining of CSF (2), LD non-functioning (2),
retrained LD tip requiring laminectomy (1), LD clotted off
(1), and positive CSF surveillance cultures (1). The length of
stay was longer for patients who had a LD complication
(6.31 days) vs no complication (5.83 days), however this
was not statistically significant (p = 0.50).
29 patients had a CSF leak (10.3%). 11 patients (3.9% of all
patients; 38.0% of patients with leak at any time) had a
CSF leak during their operative admission. 19 patients
(6.7% of all patients; 65.5% of patients with leak at any
time) had a CSF leak discovered after discharge at a future
encounter. Of the 62 patients who did not have a
preoperative LD placed, 9 (14.5%) developed a CSF Leak.
Of 220 patients who had a preoperative LD, 20 (9.1%)
developed a CSF leak. There was no statistical difference
between the two groups (p = 0.23).
CSF leak after acoustic neuroma resection is a common
complication that carries the potential for significant
morbidity. The objective of this study was to
determine if the preoperative placement of a lumbar
drain reduced the incidence of postoperative CSF leaks
after primary acoustic neuroma resection. We report
that CSF leak incidence with preoperative LD
placement is not significantly lower than without LD
use. Our patient population was unique as most
patients had a LD placed prior to surgery compared to
those who have not.
Reported CSF leak incidences with the use of routine
preoperative lumbar drain placement are limited in
current literature. At time of publication, no
randomized control trial has directly measured the
effect of preoperative lumbar drain placement on
postoperative CSF leak incidence after acoustic
neuroma microsurgery.
Placement of a LD is a relatively simple and commonly
performed procedure. As with any procedure, the
placement and maintenance of a LD is associated with
a clinically significant complication rate. We found that
5.3% of our patients with a pre-operative LD had a
complication related to their LD.
Patients – This retrospective study was completed with
the approval of the IRB at Duke University Medical
Center. The study population consisted of 282 patients
who underwent acoustic neuroma resection at our
institution between 1990 and 2014 at two Duke-affiliated
hospitals.
Patient information collected included gender, age at
presentation, race and ethnicity, acoustic neuroma
sidedness (left or right), tumor size (dimensions reported
in 3 axes), surgical resection procedure type and
approach, neurofibromatosis diagnosis (yes or no), pre-
operative stereotactic radiation (yes or no), pre-operative
lumbar drain use (yes or no), and duration of lumbar
drain placement (days).
Patient outcome variables collected included hospital
stay length (days), post-operative complication type and
frequency, lumbar drain complication type and
frequency, CSF leak rate frequency and timing (same
admission, or delayed), and recurrence on follow-up MRI
imaging (yes or no).
Statistical Analysis – All analyses were completed using
the JMP Pro 11 software suite (Cary, North Carolina,
USA). Two-by-two contingency tables were created, and
Fisher’s exact tests were performed on all variables . P-
values were reported with statistical significance fixed at
p = 0.05. Patients with insufficient demographic or
outcomes data were excluded from statistical analysis.
• We have found that the pre-operative use of a LD
for acoustic neuroma resection does not
significantly decrease the post-operative CSF leak
rate.
• The use of a LD carries a considerable risk of
complication related to its use that could cause
significant morbidity and increase hospital length of
stay.
• While a CSF leak is a common and potentially
serious complication of acoustic neuroma resection,
we believe that the routine use of a pre-operative
LD with the intent to prevent a CSF leak should be
avoided unless specific case-by-case indications are
present.
1. Mahboubi, H., et al., Complications of surgery for sporadic vestibular schwannoma.
Otolaryngol Head Neck Surg, 2014. 150(2): p. 275-81.
2. Mangus, B.D., et al., Management of cerebrospinal fluid leaks after vestibular
schwannoma surgery. Otol Neurotol, 2011. 32(9): p. 1525-9.
3. Laing, R.J., et al., A study of perioperative lumbar cerebrospinal fluid pressure in
patients undergoing acoustic neuroma surgery. Skull Base Surg, 2000. 10(4): p. 179-
85.
4. Nonaka, Y., et al., Contemporary surgical management of vestibular schwannomas:
analysis of complications and lessons learned over the past decade. Neurosurgery,
2013. 72(2 Suppl Operative): p. 103-15
5. Bien, A.G., et al., Utilization of preoperative cerebrospinal fluid drain in skull base
surgery. Skull Base, 2007. 17(2): p. 133-9
Matthew G. Crowson, MD
Resident Physician
Duke University Medical Center
Division of Otolaryngology-HNS
Durham, NC
Tel.: +1 603 306 1182
E-mail address: matthew.crowson@dm.duke.edu
Post-operative cerebrospinal fluid (CSF) leaks are
amongst the most common major complications of
acoustic neuroma (AN) microsurgery. CSF leaks after AN
microsurgery typically present with otorrhea, headache,
dizziness, and can lead to grave sequellae such as
meningitis, and brain abscess formation.[1] Meticulous
surgical technique and tight wound closure are
cornerstones for CSF leak prevention, but no formal
guidelines exist for the routine use of preoperative
lumbar drain placement to lower the incidence of CSF
leaks following AN microsurgery.
Consistent with basic fluid dynamics, CSF will flow from
the relatively high intracranial pressure region to the
relatively low-pressure regions of the eustachian tube,
middle ear space, or dehiscence in the periosteal or skin
wounds.[2] To characterize the intracranial CSF pressures
following AN microsurgery, Laing et al. measured changes
in CSF pressure and cerebrovascular hemodynamics
following AN microsurgery in humans.[3] All patients
showed a statistically significant rise in CSF pressure from
normal levels with completely reversal within 48 hours of
surgery.
CSF leak incidences with the use of routine preoperative
lumbar drain placement are limited in current literature.
Of the few studies published, CSF leak incidence has
been reported to be within 7.6-12%. [4, 5] The purpose
of this study is to retrospectively compare clinical
outcomes with the preoperative use of lumbar drain
placement during acoustic neuroma microsurgery. Patient Variables No. of patients (% of total)
Mean Age 52.3, range 14-87
Gender 161 female (57.1), 121 male (42.9)
Neurofibromatosis Type 2
Diagnosis 12 (4.3)
Mean Tumor Size (greatest
dimension) 19.1 mm +/- 10.2 mm
Pre-operative stereotactic
radiation 13 (4.6)
Post-operative stereotactic
radiation 12 (4.3)
Duke University Hospital 118 (41.8)
Duke Raleigh Hospital 164 (58.2)
Table 2. Tumor, Surgical factors and CSF Leak rate.
No. of patients (% of row)
Patient and Tumor
Variables
CSF Leak No CSF Leak p-value
No Lumbar Drain 9 (14.5) 53 (85.5)
} 0.24
Lumbar Drain 20 (9.1) 200 (90.9)
Translab. Approach 15 (12.4) 106 (87.6)
Retrosigmoid Approach 12 (9.2) 118 (90.8)
Middle Fossa Approach 2 (6.5) 29 (93.5)
Patient Age, Mean 50.4 years +/- 2.4 52.6 years +/- 0.8 0.4
Length of Stay 9.8 days +/- 0.78 5.7 days +/- 0.16 0.0001
Tumor Size, Mean 18.3 mm +/- 1.92 19.2 mm +/- 0.64 0.67
Tumor Side, Left 15 (11.8) 112 (88.2)
}0.56
Tumor Side, Right 14 (9.0) 141 (91.0)
NF-2, Yes 1 (8.33) 11 (91.7)
}1.00
NF-2, No 28 (10.4) 242 (89.6)
Pre-Operative
Radiation, Yes
1 (7.69) 12 (92.3)
}1.00
Pre-Operative
Radiation, No
28 (10.4) 241 (89.6)
Table 3. Duration of lumbar drain placement by approach
No. of patients
(% of row)
Mean, Mode
(Std. Dev)
Approach LD Placed No LD LD Placement
Duration (Days)
Retrosigmoid 82 (63.1) 48 (37.0) 2.22, 1 (1.44)
Translab. 110 (91.1) 11 (9.1) 2.86, 2 (1.36)
Middle Fossa 28 (90.3) 3 (9.7) 2.00, 2 (0.75)
NF-2: Neurofibromatosis Type 2
Translab: Translabyrinthine