posterior internal fixation

posterior internal fixation

Proceedings of the NASS 16th Annual Meeting / The Spine Journal 2 (2002) 3S–44S and plastic surgery closure. There were three deaths related to compli...

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Proceedings of the NASS 16th Annual Meeting / The Spine Journal 2 (2002) 3S–44S and plastic surgery closure. There were three deaths related to complications of multiple myeloma and progression of the patients’ underlying metastatic disease. There were no cases of iatrogenic spinal cord injury, progressive neurologic deficit or progressive kyphotic deformity. No cases had failure of the anterior cervical instrumentation, and no anterior cervical construct needed revision. No cases required additional surgery for revision of the instrumented posterior cervical fusions. Discussion: Long anterior cervical plate instrumentation has a high published incidence of failure [1], a 53% pseudarthrosis rate [2], graft displacement in 3 of 33 patients with two-level corpectomy and long plate fixation [3], anterior hardware failure in 11 of 49 patients with anterior plates and anterior hardware failure in 4 of 39 patients who underwent multilevel cervical corpectomy [4]. Posterior segmental fixation with lateral mass plates provides excellent stability and a reliable fixation of the cervical spine in cases of cervical instability involving three or more vertebral levels. Although useful as a stand-alone technique, multilevel posterior cervical lateral mass plating can have a significant protective effect on complex anterior reconstructions, especially those requiring long anterior cervical instrumentation. This series of 66 consecutive patients from three major spinal centers illustrated that posterior lateral mass fixation can be done safely with minimal morbidity while significantly enhancing the stability and durability of complex cervical reconstructions. There was no incidence of postoperative cervical kyphosis or failure of the posterior cervical fusion requiring revision. More importantly, no patient in the study had a failure of his or her anterior cervical constructs. References [1] Emery et al. [2] Vaccaro et al. [3] Pararnore et al.

Cervical spine multilevel decompression/reconstruction with anterior/ posterior internal fixation Michael L. Swank, MD, Cincinnati, OH, USA Introduction: Patients with multilevel cervical stenosis and myelopathy present a difficult decompression and reconstruction challenge. Multilevel (more than three levels) cervical surgery has been associated with a significant number of complications related to nonunions, hardware failure and respiratory complications. Various approaches, anterior only, posterior only, anterior/ posterior, have been used depending on surgeon preference and expertise. Since 1994, we have treated every patient with cervical stenosis requiring multilevel decompression and reconstruction with a combined posterior and anterior approach using lateral mass fixation posteriorly and plating anteriorly. We reviewed our experience with this approach to determine clinical efficacy as well as approach- and device-related complications. Methods: Fifty consecutive patients with cervical spinal stenosis requiring decompression and reconstruction of three or more levels were reviewed. Patients were given the North American Spine Society and Short Form (SF)-36 outcome instruments preoperatively and the SF-36 at 3 months, 1 and 2 years postoperatively as well as analog pain scores at each follow-up interval. All patients were treated by the same technique. Prophylactic methylprednisolone was administered according to the spinal cord injury protocol, and Gardner-Wells tongs were placed with 10 pounds of skull traction. Posterior decompression was then performed at stenotic levels and a posterior arthrodesis performed with local bone graft, instrumented with lateral mass screw fixation using either a plate or rod system and unicortical screw placement. Patients were then placed supine, and a left-sided carotid incision was performed. A multilevel corpectomy was then performed and reconstruction accomplished with either an allograft fibular strut or a titanium mesh cage filled with local bone graft, followed by anterior plating. No neurologic monitoring or drainage tubes were used. Patients were extubated in the recovery room, transferred to the intensive care unit overnight and then placed in a Philadelphia collar for 6 weeks. Results: The underlying pathological condition was congenital spinal stenosis with cervical spondylosis in 30 patients, OPLL in 15 patients,

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rheumatoid arthritis in 3 patients and postlaminectomy kyphosis in 2 patients. The average age at surgery was 62 years. The average follow-up was 24 months with a minimum 12-month follow-up. No patient was lost to follow-up. An average of 3.5 levels were fused, with an average incision time of 7.5 hours. All patients had a succesful arthrodesis, and no patient has been revised. One patient died during her initial hospitalization secondary to congestive heart failure, and one patient died unexpectedly 6 weeks postoperatively, presumably secondary to a late pulmonary embolism. Of the remaining 48 patients, 40 had at least some improvement in their neurologic condition, SF-36 scores and pain scores. Six remained unchanged in their overall neurologic function. Two had mild deterioration: one with a permanent C5 root injury who developed reflex sympathetic dystrophy in the ipsilateral arm, and one who had worsening gait ataxia after a postoperative hematoma from anticoagulation therapy for a postoperative pulmonary embolism. Neurologic complications included transient C5 root palsies in six patients, an apparent postoperative central cord syndrome in the patient who died from congestive heart failure, and one recurrent laryngeal nerve palsy. Respiratory complications included bilateral pneumothoraces in one patient in the recovery room, one respiratory arrest 3 days postoperatively in the patient who developed a pulmonary embolism and respiratory distress requiring reintubation in two patients on the third postoperative day. All five patients were smokers. Only one of these patients required a temporary tracheotomy. Bleeding complications were limited to the one patient who was anticoagulated with heparin while at a rehabilitation center in the first 2 weeks after surgery. Swallowing complications were experienced in nearly every patient at least transiently, but only four had persistent swallowing difficulties beyond 3 months. No patient has required any specific treatment or has been given a specific diagnosis, but it has been postulated by one otolaryngologist that the dysphagia is likely related to a superior laryngeal nerve palsy in at least two patients. Infections were limited to the posterior incision only and were observed in only one diabetic patient requiring an irrigation and debridement. Hardware complications were limited to one elderly diabetic patient who developed a posterior infection and was treated with debridement and reinstrumentation. This patient subsequently experienced gross fixation failure with loosening of her lateral mass plates but went on to successful arthrodesis. Six other patients had at least one screw loosen, but none required revision. No hardware complications were noted with anterior plate fixation. Conclusion: Multilevel, same-day, posterior-anterior cervical decompression and reconstruction with instrumentation in cervical spinal stenosis is a demanding technique-intensive procedure. However, this procedure can be performed with an operative complication rate that compares with multilevel anterior only or posterior only surgery and has a lower long-term failure rate (ie, no nonunions) than either anterior or posterior surgery alone. Lateral mass fixation in combination with anterior plate fixation can be performed without causing neurologic injury and greatly increases the likelihood of successful arthrodesis in multilevel surgeries, even in smokers. Biochemical comparison of cervical interbody cage versus structural bone graft David Lawrence Greene, MD, Providence, RI, USA; Dennis Crandall, MD, Robert H. Chamberlain, BS, Sung Chan Park, MD, Neil R. Crawford, PhD, Phoenix, AZ, USA Introduction/purpose: With the past decade’s success of threaded lumbar cages in the treatment of chronic disabling low back pain, cages have now been developed for use in cervical interbody fusion. Initial clinical results with the cervical cages display fusion rates equivalent to structural bone grafting and a significantly decreased need for iliac crest bone harvest [1]. Biomechanical comparison between cage and graft has not yet been performed. Fusion union rates in the spine have been shown to have a direct correlation to the mechanical stability of the fusion construct. In this study, immediate in vitro stability was compared between a threaded cervical cage (BAK/C; Sulzer Spine-Tech) and bone-only fusion (ACDF) both with and without anterior plating (Cervi-Lok: Sulzer Spine-Tech). Methods: Sixteen fresh frozen cadaveric specimens (ages 39 to 63 years) were separated into two matched groups based on bone densitometry testing. All soft tissues were dissected (leaving discs and ligaments intact), and the speci-