New techniques must show clear advantage

Over the past 10 years, through the successful collaboration of surgeons and industry, less-invasive techniques have been developed and popularized for treating common orthopaedic conditions. Such procedures, often incorporating arthroscopic techniques, have been successful in areas such as joint reconstruction of the knee and the shoulder.

Theoretically, minimally invasive surgery should provide outcomes that are equivalent to those resulting from traditional alternatives, while enabling a less painful recovery and a faster return to normal function. With the current emphasis on healthcare reform, such procedures should also be cost-competitive with their traditional counterparts.

Tubular lumbar diskectomy was popularized several years ago as a less invasive alternative to standard lumbar microdiskectomy. Its purported benefits include a smaller incision with less tissue dissection, allowing outpatient surgery with less pain and faster recovery. A recent article in The Journal of the American Medical Association (JAMA) by Arts and associates, however, questions these purported benefits.

The authors performed a well-powered, prospective, randomized, double-blinded, multicenter trial directly comparing early and 1-year postoperative clinical outcomes of standard versus tubular lumbar microdiskectomy. Interestingly, the authors were unable to prove a faster, less painful recovery for the newer procedure.

Instead, they found a small but statistically significant difference favoring the open microdiskectomy procedure, including less postoperative leg and back pain, less functional disability, and a higher likelihood of self-reported “good recovery” (79 percent of patients who had open microdiskectomy versus 69 percent of patients who had tubular microdiskectomy). The open procedure took less time and had fewer intraoperative and fewer postoperative complications.

This study does have some weaknesses. Patients in both groups had incisions measuring up to 30 mm, whereas the tubular procedure is designed to be accomplished with an incision half that size. In addition, the primary outcomes were measured at 8 weeks and 1 year. It may be argued that the benefits of MIS would only be seen in the very early postoperative period. The authors reported, however, that patients in both groups felt “fully recovered” at a median of 2 weeks.

Methodologically, this is a strong study. The participating surgeons were all trained and had “broad experience” in the tubular diskectomy technique. Furthermore, the surgeons were blinded to procedure by having patients follow-up with physicians who did not perform the surgery; similarly, the patients were blinded, because the incision size was the same in both groups. As a result, any potential patient bias with regard to feeling like a “winner” (had the tubular procedure) versus feeling like a “loser” (had the traditional microdiskectomy) was eliminated.

In summary, this prospective randomized analysis of tubular versus open microdiskectomy, performed using a careful, double-blinded study design, should raise questions regarding the value and benefit of this newer MIS technique as opposed to the traditional open lumbar microdiskectomy procedure.

Alan S. Hilibrand, MD, is a professor of orthopaedic surgery and neurosurgery as well as the director of medical education for the department of orthopaedic surgery at the Rothman Institute and Jefferson Medical College. He reports the following conflicts: Biomet; Zimmer; Stryker; Aesculap/B.Braun; Amedica; Medtronic; DePuy, A Johnson & Johnson Company; Osteotech; Synthes; Vertiflex; Nexgen; Benvenue Medical; Pioneer Surgical; Lifespine; Paradigm Spine; PSD; and Syndicom. He can be reached at ahilibrand@gmail.com

Comparing effectiveness
“Tubular Diskectomy vs Conventional Microdiskectomy for Sciatica: A Randomized Controlled Trial” appeared in the July 8, 2009, issue of the Journal of the American Medical Association. This report from the Leiden-The Hague Spine Intervention Prognostic Study Group (SIPS) examined the outcomes and time to recovery among 328 patients (ages 18 to 70 years old) who had persistent leg pain (longer than 8 weeks) due to lumbar disk herniations and were randomized for treatment by either conventional microdiskectomy (161 patients) or tubular diskectomy (167 patients).

According to the results of this study, use of tubular diskectomy compared with conventional microdiskectomy did not result in a statistically significant improvement in the Roland-Morris Disability Questionnaire score. Tubular diskectomy resulted in less favorable results for patient self-reported leg pain, back pain, and recovery.

AAOS Now wondered what impact these results might have on minimally invasive spine surgery, and asked two spine surgeons to weigh in on the topic.