Speculum lumbar extraforaminal microdiscectomy.
BACKGROUND
Public interest, monetary pressures and improving diagnostic techniques have placed an increasing emphasis on minimalism in lumbar disc excision. Current techniques include microlumbar discectomy and minimally invasive spinal surgery. Both are good techniques but may be painful, require a hospital stay and/or are not widely used because of difficulty acquiring the necessary skills. The author therefore developed a less invasive microscopic technique that may be performed on a consistent outpatient basis with easily acquired skills.


OBJECTIVE
The purpose of this study was to describe a variant of minimally invasive lumbar disc excision, while assessing the effects on a small group of patients.


METHODS
The treatment protocol was a prospective community hospital-based case study designed to evaluate a less invasive method of excising herniated lumbar discs residing in the canal, foraminal or far lateral space.


METHODS
This study is comprised of 50 patients with all anatomic forms of lumbar disc herniations, inside or outside the canal, at all levels except the lumbosacral joint.


METHODS
Clinical results were measured by return to work time, the criteria of MacNab and by Prolo et al.'s economic and functional criteria.


METHODS
Selection criteria included adult patients with intractable low back and leg pain, plus an imaging study revealing a lumbar disc herniation consistent with the patient's clinical presentation. Mean patient age was 48 years. The male:female ratio was approximately 2:1. All patients failed at least 3 weeks of conservative therapy. Herniations occurred from the L2-3 space through L4-5, with 30 herniations being within and 20 outside the spinal canal. Both contained and extruded/sequestered herniations were treated. Excluded from the study were patients with herniations inside the spinal canal at the L5-S1 level. Surgical approach was by microscopic speculum transforaminal route for discs residing both within and outside the lumbar canal.


RESULTS
The initial 50 consecutive patients had successful technical operations performed on an outpatient basis by this less invasive technique. By the criteria of MacNab (Table 3), 84% (42 of 50) had an excellent or good result, returning to work at a mean time of 3.5 weeks. Per Prolo et al.'s economic scale, 72% were disabled at levels I and II before surgery. Postoperatively, 92% had improved to levels IV and V. Similarly, on his functional scale, 94% functioned at levels I and II before surgery, whereas 88% achieved levels IV and V after surgery. Eighty percent required no pain medications 1 week after surgery. The only complication was an L3 minor nerve root injury as it exited the L3-4 foramen.


CONCLUSIONS
The author has described a minimally invasive technique for excising herniated discs that is applicable to all types of lumbar herniations, except for those residing in the canal at L5-S1. Clinical outcomes are comparable to those of other forms of discectomy.
Obenchain
T G
TG
Department of Neurological Surgery, Palomar Medical Center, 555 East Valley Parkway, Escondido, CA 92025, USA.
D017586:Diskectomy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D011183:Postoperative Complications; D011446:Prospective Studies; D013525:Surgical Instruments