Bruce M. McCormack

Microsurgical treatment of symptomatic sacral Tarlov cysts.

OBJECTIVE Providing relief of symptomatic radiculopathy resulting from sacral perineural cysts has proven difficult. Our goal was to improve the treatment of these cysts with microsurgical cyst fenestration and imbrication, while minimizing functional damage to neural tissues. METHODS We retrospectively reviewed the records for eight adult patients with large (2-3-cm) sacral perineural cysts who were treated at the University of California, San Francisco, between October 1992 and April 1999. All patients presented with radicular pain that was refractory to medical treatment. Three patients also reported urinary incontinence. We performed sacral laminectomies with microsurgical cyst fenestration and cyst imbrication for all patients, using intraoperative electromyography to minimize damage to the sacral nerve roots. For seven patients, we reinforced the closures with epidural fat or muscle grafts and fibrin glue application. For five patients with cysts that communicated with the subarachnoid space in computed tomographic myelograms, we placed lumbar drains for cerebrospinal fluid diversion for several days postoperatively. We assessed outcomes, using telephone questionnaires and periodic postoperative physical examinations, 3 to 73 months after surgery. RESULTS After surgery, radicular pain improved markedly for four patients and moderately for three patients; one patient with initial improvement experienced pain recurrence 9 months later. Bladder control improved markedly for two of the three patients with bladder dysfunction. There were no cerebrospinal fluid leaks and no new postoperative neurological deficits. CONCLUSION Microsurgical cyst fenestration and imbrication are effective treatments for long-term relief of refractory painful radiculopathy and urinary incontinence associated with large sacral perineural cysts.

Novel instrumentation and technique for tissue sparing posterior cervical fusion

Authors have developed a simple, disposable instrument set for posterior cervical fusion (PCF). The instruments and technique minimize soft tissue disruption and facilitate access for cervical facet joint cartilage decortication. Technique is proposed for select patients not requiring laminectomy.

Length of stay associated with posterior cervical fusion with intervertebral cages: experience from a device registry

Background Using a multi-center medical device registry, we prospectively collected a set of perioperative and clinical outcomes among patients treated with tissue-sparing, posteriorly-placed intervertebral cage fusion used in the management of symptomatic, degenerative neural compressive disorders of the cervical spine. Methods Cervical fusion utilizing posteriorly-placed intervertebral cages offers a tissue-sparing alternative to traditional instrumentation for the treatment of symptomatic cervical radiculopathy. A registry was established to prospectively collect perioperative and clinical data in a real-world clinical practice setting for patients treated via this approach. This study evaluated length of stay as well as estimated blood loss and procedural time in 271 registry patients. Results The median length of stay was 1.1, 1.1 and 1.2 days for patients having a stand-alone arthrodesis, revision of a pseudoarthrosis, and circumferential fusion (360°), respectively, and was not related to number of levels treated. Historical comparison to published literature demonstrated that average lengths of stay associated with open, posterior lateral mass fixation were consistently ≥4 days. Average blood loss (range, 32-75 mL) and procedural time (range, 51-88 min) were also diminished in patients having tissue-sparing, cervical intervertebral cage fusion compared to open posterior lateral mass fixation. Conclusions Adoption of this tissue-sparing procedure may offer substantial cost-constraining benefits by reducing the length of post-operative hospitalization by, at least, 3 days compared to traditional lateral mass fixation.

Anterior Cervical Pseudarthrosis Treated with Bilateral Posterior Cervical Cages

BACKGROUND Pseudarthrosis after anterior cervical discectomy and fusion (ACDF) causes persistent pain and related disability. Posterior revision surgery results in higher healing rates, but is more extensive compared to anterior surgery. OBJECTIVE To evaluate minimally disruptive, tissue sparing posterior fusion via bilateral placement of posterior cages between the facet joints as an alternative treatment option. METHODS A retrospective, multicenter, medical chart review was performed and included 25 patients with symptomatic pseudarthrosis after ACDF treated with posterior cervical cages, and in select cases, anterior revision. Visual analog scale (VAS) for neck and arm pain, Neck Disability Index (NDI), and perioperative metrics were collected. Fusion at 1 yr was determined via assessment of computed tomography (CT) scan and x-rays. RESULTS Mean follow-up was 18 mo. VAS neck and arm scores at last follow-up improved significantly from 7.9 ± 1.5 to 3.8 ± 2.3 and 7.24 ± 2.2 to 3.12 ± 2.5, respectively. NDI scores decreased from 65.1 ± 20.3 to 29.1 ± 17.9 at 18 mo. Fusion at 1 yr was confirmed by CT in all 17 patients with available scans and by x-ray in all 25 patients. CONCLUSION Revision of cervical pseudarthrosis after ACDF using a tissue sparing posterior approach to place cages bilaterally between the facet joints is an effective surgical strategy in select cases. Along with positive clinical and radiological outcomes, the procedure is associated with less blood loss, shorter operating times, and briefer hospital stays compared to revision with lateral mass fixation or interspinous wiring.

Perioperative complications in patients treated with posterior cervical fusion and bilateral cages

Context: Posterior cervical cages have recently become available as an alternative to lateral mass fixation in patients undergoing cervical spine surgery. Aims: The purpose of this study was to quantify the perioperative complications associated with cervical decompression and fusion in patients treated with a posterior cervical fusion (PCF) and bilateral cages. Settings and Design: A retrospective, multicenter review of prospectively collected data was performed at 11 US centers. Subjects and Methods: The charts of 89 consecutive patients with cervical radiculopathy treated surgically at one level with PCF and cages were reviewed. Three cohorts of patients were included standalone primary PCF with cages, circumferential surgery, and patients with postanterior cervical discectomy and fusion pseudarthrosis. Follow-up evaluation included clinical status and pain scale (visual analog scale). Statistical Analysis Used: The Wilcoxon test was used to test the differences for the data. The P level of 0.05 was considered significant. Results: The mean follow-up interval was 7 months (range: 62 weeks - 2 years). The overall postsurgery complication rate was 4.3%. There were two patients with neurological complications (C5 palsy, spinal cord irritation). Two patients had postoperative complications after discharge including one with atrial fibrillation and one with a parietal stroke. After accounting for relatedness to the PCF, the overall complication rate was 3.4%. The average (median) hospital stay for all three groups was 29 h. Conclusions: The results of our study show that PCF with cages can be considered a safe alternative for patients undergoing cervical spine surgery. The procedure has a favorable overall complication profile, short length of stay, and negligible blood loss.