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Kitahama et al. PLPED with EMG monitoring under general anesthesia

Figure 4: Upper half of the operative field is epidural space, lower half of that is disc spaces, and posterior longitudinal ligament (PLL) is
consisting of the boundary of these spaces (A: PLL locates the tip of bipolar coagulator); (B) sharp dissection of the lateral margin of PLL is
performed by beak forceps; (C) after that total removal of medial type lumbar disc herniation is achieved
dissection of the lateral part of PLL and subsequently The short-term operative outcome was evaluated by
electro-coagulation of the PLL [Figure 4B and C]. NRS score. Post-operatively, NRS score of the affected
leg significantly improved from 6.4 to 0.9 (P < 0.05)
Date analysis [Figure 5]. To evaluate wound pain, we also examined
The operative outcomes were evaluated by two NRS score of operative site on the day following the
methods: (1) the change of pre- and postoperative operation. The mean NRS score was 0.8 in the next
numeric rating scale (NRS) scores of affected leg pain morning [Figure 5].
and NRS score of operative site pain; (2) MacNab’s
[11]
criteria rating activities of daily life at the most recent The long-term operative outcome was evaluated
examination. According to the criteria, the results by MacNab’s criteria. The patient was asked to rate
were described as excellent (completely pain free), the level of well-being at an average of 13.5 months
good (minor intermittent discomfort, not interfering after the operation (range: 1-30 months). “Excellent”
with normal activities), fair (improvement in symptoms or “good” ratings were obtained from 91.5% patients.
but persistent backache or sciatica interfering with “Fair” was obtained from 8.5% patients and no patient
capacity to engage in full normal activities) and poor chose “poor” as per the MacNab’s criteria [Table 2].
(no change in symptoms). Statistical analysis was
[12]
performed with Student’s paired t-test. P values < 0.05 Mean operative time was 66.7 (range 38-152) min and
were considered statistically significant. intraoperative blood loss was negligible in all cases.
Mean time to ambulation was 7.2 (range 2-20) h.
RESULTS Mean hospital stay was 4.4 (range 1-33) days and the
average duration of return to work was 17.2 (range
A single level of PLPED for consecutive 48 cases was 5-56) days [Table 3]. Although no serious complication
examined. The mean age of patients (23 men, 25 occurred, 4 cases had minor transient neurological
women) was 50.7 (range 17-88) years old. One patient deficits. One patient (2.1%) complained of dysesthesia
underwent PLPED at L1-2 level, 3 at L2-3, 7 at L3-4, of affected ENR area, but the dysesthesia has been
29 at L4-5 and 8 at L5-S or L5-6 [Table 1]. gradually improving. Three patients (6.3%) had a
transient paresis that had completely disappeared
after 3 months [Table 4]. No recurrence LDH was

Table 1: Background data of the patients
Characteristics Data
Gender
Male 23
Female 25
Age (years), mean (range) 50.7 (17-88)
Level
L1-2 1
L2-3 3
L3-4 7
L4-5 29
L5-S, L5-6 8
Figure 5: The short term operative outcome evaluated by numeric Type of herniation
rating scale (NRS) score. Left and middle bar show the significant Medial 13
change of NRS score of affected leg pain (*P < 0.05). Right bar is Foraminal 32
NRS score of operative site on the day following the operation Lateral 3
112 Mini-invasive Surgery ¦ Volume 1 ¦ September 30