Clin Orthop Surg.  2017 Mar;9(1):71-76. 10.4055/cios.2017.9.1.71.

Assessment of Anteroposterior Subpedicular Approach and Oblique Scotty Dog Subpedicular Approach for Selective Nerve Root Block

• Kaliya-Perumal AK
• Yeh YC
• Luo CA
• Joey-Tan K

• KMID: 2412306
• DOI: http://doi.org/10.4055/cios.2017.9.1.71

Abstract

BACKGROUND
The technique used to administer a selective nerve root block (SNRB) varies depending on individual expertise. Both the anteroposterior (AP) subpedicular approach and oblique Scotty dog subpedicular approach are widely practiced. However, the literature does not provide a clear consensus regarding which approach is more suitable. Hence, we decided to analyse the procedural parameters and clinical outcomes following SNRBs using these two approaches.
METHODS
Patients diagnosed with a single lumbar herniated intervertebral disc (HIVD) refractory to conservative management but not willing for immediate surgery were selected for a prospective nonrandomized comparative study. An SNRB was administered as a therapeutic alternative using the AP subpedicular approach in one group (n = 25; mean age, 45 ± 5.4 years) and the oblique Scotty dog subpedicular approach in the other group (n = 22; mean age, 43.8 ± 4.7 years). Results were compared in terms of the duration of the procedure, the number of C-arm exposures, accuracy, pain relief, functional outcome and the duration of relief.
RESULTS
Our results suggest that the oblique Scotty dog subpedicular approach took a significantly longer duration (p = 0.02) and a greater number of C-arm exposures (p = 0.001). But, its accuracy of needle placement was 95.5% compared to only 72% using the AP subpedicular approach (p = 0.03). There was no significant difference in terms of clinical outcomes between these approaches.
CONCLUSIONS
The AP subpedicular approach was simple and facile, but the oblique Scotty dog subpedicular approach was more accurate. However, a brief window period of pain relief was achieved irrespective of the approaching technique used.

Keyword

Intervertebral disc displacement; Nerve root compression; Radiculopathy

MeSH Terms

Adult
Female
Humans
Intervertebral Disc Displacement/complications/*diagnostic imaging
Male
Middle Aged
Nerve Block/*methods
Pain Management/*methods
Prospective Studies
Radiography, Interventional/*methods
Sciatica/etiology/*therapy
*Spinal Nerve Roots

Figure

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  Fig. 1 Needle placement using the anteroposterior subpedicular approach.

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  Fig. 2 Needle placement using the oblique Scotty dog subpedicular approach. The needle is visualized almost as a single point just below the neck of the Scotty dog.

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  Fig. 3 Successful attempt characterized by appropriate spread of contrast along the nerve root.

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  Fig. 4 Failed attempt showing vague contrast spread.

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