Herniated lumbar disk disease with radicular leg pain is one of the most common pathologies treated by the spinal surgeon. With this condition, the surgical goal is to alleviate radicular symptoms by removing loose herniated disk fragments and decompressing the symptomatic nerve root(s). Microdiscectomy has been shown to be one of the most successful and cost effective procedure in the medical field. Lumbar microdiscectomy can easily be performed through a tubular retractor system which represents the predominant MIS technique at the present time. A small subset of surgeons use a transforaminal technique, employing equipment similar to arthroscopic surgery. For surgeons new to MISS, the lumbar microdiscectomy procedure is a logical starting point in the learning curve.

After the administration of prophylactic antibiotics, lower extremity compression stockings, and anesthesia, the patient is positioned prone on a radiolucent spine frame such as a Jackson table (Mizuho OSI) (Fig. 34.1). The lumbar spine is prepped and draped in a sterile fashion. The surgical technique for lumbar microdiscectomy with a tubular retractor system begins with lateral radiographic localization of the incision (Fig. 34.2A, B). This step is mandatory to ensure that an optimal trajectory to the surgical pathology is taken. The paramedian incision is generally made about 2 to 3 cm lateral to the midline on the side of the herniation. With palpation of the bony landmarks, a spinal needle is introduced lateral to the midline structures, along the proposed trajectory of the tubular retractor system. Lateral fluoroscopy is utilized to adjust the needle as necessary until an optimal position is achieved. After localization, a skin incision is made equal in length to the diameter of the tubular retractor. The incision is made sharply through the skin
and lumbodorsal fascia. Subperiosteal dissection is performed with a small Cobb elevator, elevating muscle tissue off the lamina and preparing a docking site for the tubular retractor. Sequential dilation is then performed to dilate the soft tissues and prepare a path from the skin to the spinal column (Fig. 34.3). After determining the depth from the skin to the lamina, the correct tubular retractor is selected and introduced over the sequential dilators. The tubular retractor is secured to the operating table and a lateral radiographic view is obtained to ensure proper localization of the retractor (Fig. 34.4A, B).

The preferred visualization strategy during surgery involves the use of an operative microscope which provides excellent magnification and illumination of the surgical field. The optics of the operative microscope allow the surgeon to see clearly at the base of a long narrow tube (Fig. 34.5). In contrast, telescopic glasses generally provide less optimal visualization. Endoscopic visualization has been utilized in the past but provides an inferior two-dimensional image. The endoscope is also prone to smudging of the lens during surgery and is not widely used at the current time.

With good visualization and lighting provided by the operative microscope, any residual soft tissue is removed with electrocautery to expose the bony elements. A laminotomy is then performed using instruments analogous to traditional microdiscectomy surgery. The author prefers to use a high-speed burr/drill to thin the bone of the lamina. Next, curved curettes are utilized to demarcate
the plane between the lamina bone and ligamentum flavum. The spinal canal and epidural space are entered by traversing the ligamentum flavum. The bone of the medial portion of the facet joint is trimmed to expose the shoulder of the traversing nerve roots. The pedicle is an important surgical landmark and can be palpated using a small ball-tipped probe. This landmark can be utilized to identify the location of migrated disk fragments which can be correlated to preoperative imaging studies. The ventral epidural space is explored and released with a small ball-tipped probe, and the herniation is generally palpated at this point. A nerve root retractor can be placed allowing the herniated disk to be visualized. Rather than cut the annulus, the author prefers to break the membrane overlying the herniation with a Penfield #4. Working through the already present annular fissure, disk space can be explored. Any loose disk fragments are removed from the spinal canal and disk space. After the surgeon is confident that all loose disk material has been removed, the nerve roots are checked to be sure they are free of any further compression.