Clinical and Radiologic Comparison of Minimally Invasive Surgery With Traditional Open Transforaminal Lumbar Interbody Fusion: A Review of 452 Patients From a Single Center.

STUDY DESIGN: Retrospective analysis of prospective data for parallel, consecutive series of patients (Level III). OBJECTIVE: Compare clinical results and radiographic outcomes of minimally invasive surgery (MIS) versus open techniques for transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA: Minimally invasive techniques allow transforaminal exposure with decreased soft tissue disruption, but the question remains whether surgical and functional outcomes are equivalent to open techniques. MATERIALS AND METHODS: A consecutive series of 452 1 or 2-level TLIF patients at a single institution between 2002 and 2008 were analyzed. A total of 148 were MIS patients and 304 were open. Operative time, estimated blood loss, infection rate, and hospital length of stay were recorded. Oswestry disability index (ODI) and visual analog (VAS) pain scores were documented preoperatively and postoperatively. Fusion was assessed radiologically at a minimum of 1 year follow-up. RESULTS: There were proportionally more 2-level than 1-level procedures in the open group compared with the MIS group; there were more Workers' Compensation patients among 1-level procedures than 2-level. There were more Spondylolisthesis patients and fewer Degenerative Disk Disease patients among one-level procedures compared with 2-level. Blood loss and operative time were lower in the MIS group. Length of hospital stay in the MIS cohort was shorter compared with the open cohort. There were 3 deep wound infections in the open cohort. ODI and VAS (leg and back) scores improved in both groups at 1 year compared with preoperative scores and did not differ between MIS and open cohorts. Fusion rate was similar for both groups (91% overall). One-level procedures and BMP use were associated with higher fusion rate, regardless of approach. CONCLUSIONS: MIS TLIF produces comparable clinical and radiologic outcomes to open TLIF with the benefits of decreased intraoperative blood losses, shorter operative times, shorter hospital stays, and fewer deep wound infections.

Disc space injection with marcaine as a method to evaluate painful nonunion of an interbody fusion device: a case report.

BACKGROUND CONTEXT: Discography has been successfully used to distinguish painful from asymptomatic intervertebral discs. PURPOSE: To report a case of chronic back pain following two-level interbody and posterolateral fusion in the lumbar spine that was evaluated with marcaine injection into the disc space. STUDY DESIGN: Case report. METHODS: A patient with chronic back pain after a two-level anteroposterior lumbar fusion was evaluated. A complete description of the history, physical examination, and relevant radiographic images along with a brief review of the pertinent literature are included. RESULTS: Injection of marcaine into the area of previous interbody fusion resolved the painful symptoms, and surgery confirmed the nonunion. CONCLUSIONS: In cases of interbody lumbar fusion with questionable solidity, marcain injection within the disc space can help in the assessment of the source of pain even at the intervertebral spaces with cages.

Measurement of in vivo intradiscal pressure in healthy thoracic intervertebral discs.

STUDY DESIGN: In vivo pressures were measured in radiologically healthy middle and lower thoracic discs in 6 adult volunteers. OBJECTIVES: To quantify and compare intradiscal pressures from the middle and lower thoracic spine during various body positions and maneuvers, and to investigate the potential variation of these pressures with orientation of the measurement transducer. SUMMARY OF BACKGROUND DATA: In vivo intradiscal pressures have been reported for the lumbar spine; however, the authors are unaware of any studies presenting intradiscal pressures in the thoracic spine. METHODS: A specially constructed pressure-sensing needle was inserted into the nucleus pulposa, and pressures were recorded during a variety of body positions and maneuvers in middle and lower thoracic discs in 6 study participants. In three of the body positions, pressures were measured with the needle in both vertical and horizontal orientations to investigate whether the measured pressures were directionally dependent. RESULTS: Intradiscal pressure varied significantly with body position and maneuver, with pressures being greatest in positions where study participants held 10-kg weights in each hand. Disc level and orientation of the pressure needle did not significantly influence intradiscal pressure. In some body positions, thoracic intradiscal pressures were significantly different from previously reported pressures from the lumbar spine. CONCLUSIONS: Thoracic intradiscal pressure was significantly influenced by body position and maneuver but not disc level. Intradiscal pressures are useful for gaining greater insight into the biomechanics of the thoracic spine.