207 / 264
underwent surgery 26 months after radiosurgery for
treatment of medically intractable trigeminal neuralgia.
The median time interval between primary treatment
and salvage surgery was 36 months (range 9.6–153
months). The median tumor size at time of salvage sur-
gery was 2.0 cm (range 0.6–4.1 cm), and the median
amount of posttreatment tumor growth was 0.7 cm (range
0.3–1.8 cm). At the time of tumor progression, no patients
had purely intracanalicular tumors; seven (19%) demon-
strated primarily cystic tumor growth; two (5%) had asso-
ciated brainstem edema; and 14 (38%) had varying
degrees of brainstem compression on imaging, which was
not different from controls. Table II summarizes the clini-
cal characteristics of patients at the time of salvage sur-
gery with comparison to matched controls. Patients
presenting for salvage therapy had poorer hearing com-
pared to matched controls (
P
5
0.001); otherwise, there
were no differences between groups prior to microsurgery.
Surgical Salvage
Operative data are summarized in Table III. Previ-
ously radiated patients underwent either a translabyrin-
thine (14; 38%) or retrosigmoid (23; 62%) approach for
surgical salvage. Eighteen (49%) patients underwent
gross total, 10 (27%) near total, and nine (24%) subtotal
resection. The most common indication for near- or sub-
total resection was to preserve facial nerve integrity. In
contrast, the majority of matched controls underwent
GTR (30; 81%), a difference that was statistically signifi-
cant (
P
5
0.01).
Intraoperative facial nerve electroprognostic testing
was performed using proximal minimum stimulation
thresholds or the supramaximal stimulation technique
described previously.
14
Facial nerve dissection was noted
to be subjectively more difficult secondary to adherent
and or poorly defined surgical planes at the nerve–tumor
interface. The facial nerve was anatomically intact at
the end of the operation in 95% (35) of cases following
radiation and in 100% of all control subjects. In two pre-
viously irradiated cases, the anatomical continuity of the
facial nerve was lost while dissecting thinly splayed
nerve fibers. The single patient with a nongrowing
tumor who underwent salvage surgery for intractable
trigeminal neuralgia experienced symptom resolution
following surgery.
Complications
The rate of postoperative cerebrospinal fluid (CSF)
leak requiring reoperation in radiated cases was 11% (n
5
4). One case occurred in a delayed fashion over 12
months following surgery and developed subsequent
meningitis, requiring return to the operating room. Two
additional cases of early postoperative CSF wound leaks
from the craniotomy incision occurred and were success-
fully managed with suture reinforcement of the skin clo-
sure. One patient with prior radiation (3%) suffered
brainstem stroke following salvage surgery, with resid-
ual neurologic deficits including mild hemiparesis and
ataxia, but currently lives independently, whereas none
of the control subjects experienced postoperative stroke.
Overall complication rates were not significantly differ-
ent compared to matched controls (Table III).
Facial Nerve Function and Tumor Control
Following Salvage Surgery
The median length of radiologic follow-up after sal-
vage surgery was 26.4 months (range 3–114 months),
which was not statistically significantly different than
duration of follow-up for controls (
P
5
0.7). At last
follow-up, no recurrences in cases of GTR, or progressive
growth of tumor remnants in less than GTR resection
cases, were diagnosed on imaging in either group. Facial
nerve outcomes are summarized in Table IV and Figure
2. At last follow-up, good facial nerve function (HB I-II)
was observed in 27 (73%) of the patients who underwent
primary radiation therapy compared to 28 (76%) controls
(
P
5
0.8). Notably, when only analyzing patients with
normal preoperative facial nerve function, excluding the
two study subjects with post-SRS facial nerve paresis,
27 of 35 (77%) retained good long-term postoperative
facial nerve function following salvage surgery. After
adjusting for age, tumor size, extent of resection, and
duration of follow-up using logistic regression modeling,
there was no difference in rate of satisfactory facial
TABLE III.
Surgical Approach, Extent of Resection, and Complications
Following Salvage Surgery of Previously Irradiated VS
Compared to Matched Controls.
Feature
Primary
RT n (%)
Matched
Control n (%)
P
Value
Surgical Approach
Retrosigmoid
23 (62%)
30 (81%)
0.1
Translabyrinthine
14 (38%)
7 (19%)
Extent of Resection
Gross total
18 (49%)
30 (81%)
0.01*
Near total
10 (27%)
4 (11%)
Subtotal
9 (24%)
3 (8%)
Complications
Stroke
1 (3%)
0
1.0
Hydrocephalus
0
1 (3%)
1.0
CSF leak
4 (11%)
4 (11%)
1.0
Meningitis
2 (5%)
0
0.5
CSF
5
cerebrospinal fluid. RT
5
radiation therapy; VS
5
vestibular
schwannoma.
TABLE IV.
Surgical outcomes. Postoperative House-Brackmann Score
Feature
Primary RT*
n (%)
Matched Control
n (%)
P
Value
I–II
27 (73%)
28 (76%)
III–IV
8 (22%)
8 (22%)
0.8
V–VI
2 (5%)
1 (3%)
*Includes two patients who had preoperative facial nerve paresis fol-
lowing prior radiation therapy.
RT
5
radiotherapy.
Wise et al.: Surgical Salvage for Recurrent VS
186