Do position and size matter? An analysis of cage and placement variables for optimum lordosis in PLIF reconstruction.

PURPOSE: To examine monosegmental lordosis after posterior lumbar interbody fusion (PLIF) surgery and relate lordosis to cage size, shape, and placement. METHODS: Eighty-three consecutive patients underwent single-level PLIF with paired identical lordotic cages involving a wide decompression and bilateral facetectomies. Cage parameters relating to size (height, lordosis, and length) and placement (expressed as a ratio relative to the length of the inferior vertebral endplate) were recorded. Centre point ratio (CPR) was the distance to the centre of both cages and indicated mean position of both cages. Posterior gap ratio (PGR) was the distance to the most posterior cage and indicated position and cage length indirectly. Relationships between lordosis and cage parameters were explored. RESULTS: Mean lordosis increased by 5.98° (SD 6.86°). The cages used varied in length from 20 to 27 mm, in lordosis from 10° to 18°, and in anterior cage height from 10 to 17 mm. The mean cage placement as determined by CPR was 0.54 and by PGR was 0.16. The significant correlations were: both CPR and PGR with lordosis gain at surgery (r = 0.597 and 0.537, respectively, p < 0.001 both), cage lordosis with the final lordosis (r = 0.234, p < 0.05), and anterior cage height was negatively correlated with a change in lordosis (r = -0.297, p < 0.01). CONCLUSION: Cage size, shape, and position, in addition to surgical technique, determine lordosis during PLIF surgery. Anterior placement with sufficient "clear space" behind the cages is recommended. In addition, cages should be of moderate height and length, so that they act as an effective pivot for lordosis.

Selection of fusion levels in adolescent idiopathic scoliosis using fulcrum bending prediction: a prospective study.

STUDY DESIGN: A prospective study of 50 consecutive patients undergoing selective thoracic fusion for idiopathic scoliosis with minimum 2 year follow-up. OBJECTIVE: We aim to establish the validity and safety of a new strategy using fulcrum bending (FB) radiographs and the inherent flexibility of the curve to select fusion levels for King type 2 and 3 curves (Lenke 1a, 1b, and 1c). The purpose of this new strategy is to preserve motion segments compared to the traditional method of selecting fusion levels. SUMMARY OF BACKGROUND DATA: The aim of fusion in idiopathic scoliosis is to achieve a balanced spine with the shortest fusion preserving motion segments particularly in the lumbar spine. Conventional strategies for choosing fusion levels have been based on the standing radiographs and have not taken into account the flexibility of the curve. METHODS: We followed 50 consecutive patients who underwent selective thoracic fusion for King 2 and 3 curves (Lenke 1a, 1b, and 1c). The fusion levels were chosen based on our new strategy using the FB radiograph. Twenty-five patients were fused using a hook system and 25 with a hybrid system of hooks and screws. All patients were observed until skeletal maturity and a minimum of 2 years. The curve correction, trunk shift, radiographic shoulder height, list were recorded at the preoperative stage, postoperative stage, and final follow-up. RESULTS: The patients had an average age of 15.4 years. The average preoperative Cobb angle was 55.4 degrees and final follow-up Cobb angle for the primary curve was 24.1 degrees, with no difference between the 2 groups. With the new strategy, we were able to save levels in 31 patients (62%), compared to the conventional method of selecting the lowest instrumented vertebra. There was a statistically significant difference in the correction of the fusion mass Cobb angle between the hook and hybrid groups. There was significant improvement in the trunk shift after surgery. Ninety-six percent of patients had balanced or minimally imbalanced shoulders at final follow-up. Three patients had tilting of the vertebra below the fusion mass into the primary curve that did not progress at skeletal maturity. CONCLUSION: The new objective strategy for determining fusion levels using FB radiographs is safe and effective. With considering the flexibility of the curve, we are able to save levels distally in over 60% of patients. This strategy takes into account the power of modern instrumentation.

A brief overview of evidence-informed management of chronic low back pain with surgery.

The management of chronic low back pain (CLBP) has proven to be very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-informed management of chronic low back pain without surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Although this special focus issue was focused on nonoperative care, it was deemed important to provide an overview of the surgical management of CLBP. This is intended to inform stakeholders of surgical options that are available to them should nonsurgical interventions prove ineffective or contraindicated. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.

Painful lumbosacral melorheostosis treated by fusion.

STUDY DESIGN: A case report of low back pain associated with a diagnosis of melorheostosis of the lumbosacral spine. OBJECTIVE: To describe a rare presentation of melorheostosis and subsequent successful surgical treatment. SUMMARY OF BACKGROUND DATA: Melorheostosis is a rare condition and spinal pain has not been described in association with the condition. METHODS: A patient with disabling low back pain and suspected melorheostosis of the lumbosacral spine responded favorably to diagnostic facet joint blocks. Treatment was lumbosacral fusion and biopsy of the abnormal bone. The densely sclerotic bone presented technical difficulties requiring modification of surgical technique. RESULTS: Dramatic pain and disability reduction occurred following lumbosacral fusion. Histologic examination was consistent with melorheostosis. CONCLUSION: Melorheostosis rarely causes severe low back pain that can respond favorably to fusion surgery.