The history of open surgical treatment of herniated lumbar
discs started over sixty years ago. Williams described Microlumbar Discectomy
in 1978 [31]. This is a small incision technique using an external overhead
microscope. It is, of course, a small open operation which requires a posterior
midline skin incision of at least one inch (for one level), incision of
paravertebral fascia, detachment of muscle, removal of a portion of the
ligamentum flavum, usually bone removal, retraction of the root and dural
sac, and opening of the disc inside the spinal canal.
Minimally invasive methods, performed by passing the scope from
the skin surface, should be differentiated from open surgery. These are puncture
opening (percutaneous) procedures, (with skin openings just large enough
to admit the scope), for internal viewing through scope placement directly
at the tissue, to be addressed as compared to working from an external view,
(either with or without a microscope), through an open incision.
The evolution of these percutaneous methods to the current state-of-the-art
can be traced with an historical overview of the basic approaches:
chemonucleolysis [15], laser [5], manual, and automated percutaneous lumbar
discectomy [21, 24, 25, 27], and arthroscopy [17]. In 1948, Valls, et al.
[30], and in 1956, Craig [3], described the posterior lateral approach for
bone biopsy. Lyman Smith first used Chymopapain to treat a lumbar disc disorder
in 1964 [29]. The posterolateral extradural route to the lumbar disc was
described by Day in 1969 [6]. Percutaneous nucleotomy was developed by Hijikata
in 1975 [12, 13, 14]; Kambin, in 1983 [17], and thereafter, described
arthroscopic techniques and equipment for posterior and posterolateral herniated
disc removal, via intradiscal access [18]. Then, in 1985, Onik [24] developed
the nucleotome for automated percutaneous lumbar discectomy. In 1987, Choy
reported using laser to treat herniated lumbar discs [1]. Subsequently, in
1993, percutaneous endoscopic discectomy with a medium-size, straight, rigid
endoscope, at L4-5 and above, was described by Mayer and Brock [21], in a
prospective, randomized series of cases, using manual and automated tools;
they reported 95% of endoscopic patients returning to their previous occupations,
compared to 72% in their open microdiscectomy group.
More recently, Kambin and others have described larger scope "foraminal access"
approaches [19], but since straight scopes will not go around corners, and
large scopes will not pass into small openings, these efforts have been limited
to working inside the foramen, or perhaps reaching tools though the foramen,
without the advantage of having the entire scope go through in such a way
that the scope itself is directly on the actual herniation.
The small, guided endoscopic, completely transforaminal technique (the subject
of this paper) was described in detail at the AANS meeting in April, 1996
[8], and was commended by Dr. Dunsker, an official of the AANS, as "the surgery
of the future."[9] (pers. comm.)
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