Prevalence of symptomatic lumbar disc herniation is 1-3% in the adult population.1 When conservative therapy (e.g., physiotherapy, anti-inflammatories, epidural injections, etc.) fails, open microsurgical discectomy is regarded as the treatment of choice. With this procedure, the incidence of injury to visceral bowel is reported to be 3.8 per 10,000 cases. 2 With the recent advent of tubular retractor systems, an increasing number of surgeons are using this minimally invasive procedure to replace traditional open microsurgical discectomy. The advantages include a smaller skin incision and a muscle splitting rather than muscle incising technique. As a result post-operative pain, blood loss and length of hospital stay may decrease significantly. [3][4][5][6] Multiple studies have compared the two surgical techniques with regards to their clinical outcomes. 6,7 The results of these studies reveal equal if not superior clinical outcomes with the minimally invasive technique. Despite the success of the minimally invasive microdiscectomy, none of the studies reported any intraoperative complications using this novel technique. This report represents the first documented bowel injury using METRx tubular retractors (Medtronic Sofamor-Danek, Memphis, TN) for minimally invasive lumbar microsurgical discectomy.
CASE REPORT
Clinical HistoryA 36 year old female with severe back pain, and right lower limb radicular symptoms referred to Neurosurgery to assess for possible surgical intervention. Magnetic resonance imaging (MRI) of lumbar spine revealed L5-S1 paramedian disc herniation which was consistent with clinical findings (see Figures 1a & 1b). Trial of conservative therapy was not effective hence, patient agreed to have lumbar discectomy done. The less invasive method of using METRx tubular retractors for the discectomy was offered to the patient. The patient agreed to the procedure upon discussion of potential benefits and possible complications.
Minimally Invasive MicrodiscectomyUnder general anesthesia, the patient was placed prone on the Wilson frame. Using fluoroscopy, a Kirschner wire was docked onto the right side of the L5 lamina and a 1.5cm skin incision was made. The METRx tubular retractor was then introduced in standard fashion over sequential dilators and the microscope brought in. Following laminotomy and removal of ligamentum flavum, the anticipated large disc herniation distorting the S1 nerve root was encountered. The disc was incised, and the
THE CANADIAN JOURNAL OF NEUROLOGICAL SCIENCES 485Bowel Injury following Lumbar Discectomy using Minimally Invasive Retractors Aleksa Cenic, Niv Sne, Michael Lisi, Allan Okrainac, Kesava Reddy, Can. J. Neurol. Sci. 2007; 34: 485-487 PEER REVIEWED LETTER fragment removed with pituitary rongeurs. The end-plates of L5 and S1 were scraped using reverse-angled curettes. Copious bacitracin irrigation of the disc space was performed ensuring no residual loose disc pieces. Upon inspection, the nerve root was well decompressed. Hemostasis was achieved with bone wax
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