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Orthopaedic Surgery Spine
Figure 7: Typical Radiographic and Endoscopic Views during Table 1: Clinical Outcomes Using Modified McNab Criteria versus
Transforaminal Decompression Foraminal Zone Classification
AD
Zone
Outcome Entry Zone Exit Zone Middle Zone Total
Excellent Count 3 7 6 16
Expected count 5.6 5.6 4.8 16.0
Within outcome (%) 18.8 43.8 37.5 100.0
Good Count 2 6 5 13
Expected count 4.6 4.6 3.9 13.0
Within outcome (%) 81.8 9.1 9.1 100.0
Poor/Fair Count 9 1 1 11
BE
Expected count 3.9 3.9 3.3 11.0
Within outcome (%) 81.8 9.1 9.1 100.0
Total Count 14 14 12 40
Expected count 14.0 14.0 12.0 40.0
Within outcome (%) 35.0 35.0 30.0 100.0
Chi-Square Tests
Value df Asymp. Sig.
(2-sided)
CF
Pearson chi-square 14.660
a
4 0.005
Likelihood ratio 14.774 4 0.005
Valid cases (n) 40
a. Seven cells (77.8%) have an expected count of less than 5. The minimum expected count is 3.30.
Table 2: Chi-Square Tests
Z Value df Asymp. Sig.
(2-sided)
A–B: intraoperative fluoroscopy images in the AP (Figure 7a) and in the lateral (Figure 7b) plane. Note, the
Over 50 Pearson chi-square 11.606
a
4 0.021
reamer is advanced to the medial interpedicular line on the AP and to the posterior vertebral body wall on the
lateral view; C: typical view of an endoscopic reamer after transforaminal decompression with bone wrapped
Likelihood ratio 14.883 4 0.005
around the instrument; D–F: endoscopic views after transforaminal placement of the endoscope showing Valid cases (n) 18
reamed facet joint (F) and debrided intervertebral disc (D); E: decompressed neuroforamen with F, D, epidural
Under 50 Pearson chi-square 3.858
b
4 0.426
fat (EF) and exiting nerve root (N); and F: application of the radiofrequency probe (RFP) for shrinking disc
material and controlling epidural bleeding.
Likelihood ratio 4.573 4 0.334
Valid cases (n) 22
counts of variable combinations if no association was found between
a. Nine cells (100.0%) have an expected count of less than 5. The minimum expected count is 0.82.
clinical outcome and zone classification of foraminal stenosis and
b. Nine cells (100.0%) have an expected count of less than 5. The minimum expected count is 1.11.
variable distribution was equal. The Pearson chi-square and the
likelihood-ratio chi-square tests were used as statistical measures Fair and poor results were seen in 11 patients and 81.8% of these
of association. occurred in patients with foraminal stenosis in the entry zone (see
Table 1). The differences in clinical outcomes were statistically
Results significant (p<0.005; see Table 1). Age above 50 years was identified
There were 40 patients (26 females and 14 males). The average age was as an additional risk factor for fair to poor outcomes with statistical
52.4 years, ranging from 37 to 86 years. The follow-up period ranged significance (p=0.021; see Table 2 and Figures 8–10). Seven of the 11
from 12 to 15 months. Each patient underwent a single-level operation. patients with foraminal stenosis in the entry zone and fair to poor
Thus, the number of levels equals the number of patients. The L5–S1 clinical outcomes were above 50 years of age.
segment was the most commonly involved level (22 cases, 55.0%)
followed by L4–5 (16 cases, 40.0%) and L3–4 (two cases, 5.0%). Discussion
Stenotic lesions were localised in the entry zone in 14 patients, in the Pre-operative planning is essential in achieving excellent and good
middle zone in 12 patients and in the exit zone in another 14 patients outcomes with the TES for foraminal stenosis. Although the
(see Table 1). According to modified McNab criteria, 16 patients had effectiveness of the procedure has been demonstrated by multiple
excellent outcomes and 13 patients had good outcomes. Eleven patients investigators,
1–12,15–18
clinical data are less favourable for foraminal
had fair to poor outcomes, and nine of these 11 patients required stenosis than for herniated disc, where clinical success rates
re-operation with laminectomy. Complications included transitory upwards of 90% are expected. This is certainly demonstrated by our
neurogenic leg pain in six cases due to dorsal root ganglion (DRG) studies, which showed excellent and good results in 72.5% (29/40) of
irritation. There were no infections. the patients undergoing foraminoplasty in the exit and middle zone
of the neuroforamen.
The mean VAS score decreased from 7.2±1.4 pre-operatively to
2.3±1.6 at final follow-up (p<0.01). According to the modified Since sciatica and neurogenic claudication were the main reasons for
Macnab criteria, excellent and good results were mostly seen in surgical intervention, reduction of leg pain was analysed using a VAS.
patients with middle and exit zone foraminal stenosis (see Table 1). There was a significant improvement in the VAS and the clinical
50 EUROPEAN MUSCULOSKELETAL REVIEW
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