Complications and results of long adult deformity fusions down to l4, l5, and the sacrum.

STUDY DESIGN: This is a consecutive study of patients having undergone surgical treatment of adult lumbar scoliosis. Follow-up ranged from 2 to 13 years (average 5 years). OBJECTIVES: To assess the complications and outcomes of patients with long fusions to L4 (n=23), L5 (n=21), or the sacrum (n=15) and determine if a "deeply seated" L5 segment is protective. SUMMARY OF BACKGROUND DATA: Few studies assess outcomes and complications in adults fused from the thoracic spine to L4, L5, or the sacrum with minimum 2-year follow-up. METHODS: Fifty-eight patients (59 cases; average age 43 years; range 21 to 60) with minimum 2-year follow-up were analyzed for subsequent spinal degeneration and complications. Outcomes were assessed from questionnaires administered at latest follow-up. RESULTS: Sixteen percent of cases (7 of 44) fused short of the sacrum displayed subsequent postoperative distal spinal degeneration, although only three patients were symptomatic. Compared with the group with no subsequent degeneration, this group had a lower improvement in function and pain relief. Other complications for patients fused short of the sacrum included two cases with crosslink breakage, one with neurologic deficit, three with pseudarthroses, one with hook pullout, and one with L5 screw pullout. For cases fused to the sacrum, two cases with deep wound infections and one with loose iliac screw requiring removal were observed. Because two of four cases fused to L5 with subsequent degeneration at L5-S1 were observed to have "deeply seated" L5 segments and two of the four did not, the authors could conclude only that "deep seating" of L5 is not absolute protection. CONCLUSIONS: Fusions short of the sacrum did not have predictable long-term results. Those fused short of the sacrum who developed distal spinal degeneration had worse outcomes. Patients fused to the sacrum did not have a higher complication rate. A "deeply seated" L5 segment does not necessarily protect the L5-S1 disc.

Long-term complications in adult spinal deformity patients having combined surgery a comparison of primary to revision patients.

STUDY DESIGN: This is a comparison of primary (N = 18) to revision (N = 26) combined (anterior and posterior surgery) adult spinal deformity patients with regard to late (>6 months) complications and radiographic/functional outcomes at a minimum 2-year follow-up. OBJECTIVES: To determine whether revision status increases the risk of late complications or offers a poor prognosis for functional outcome in adult deformity patients. SUMMARY OF BACKGROUND DATA: It is known that patients who have combined surgery for adult deformity have a high incidence of perioperative complications. Long-term complications and the effect of revision status have not been clarified in the literature. The functional outcomes for these patients are unclear as to whether or not there is a difference between primary and revision patients. Outside the arena of adult spinal deformity the functional outcomes for revision cases have been disappointing. METHODS: A consecutive series of 44 patients who underwent combined procedures for adult spinal deformity were followed for a minimum of 2 years (average follow-up 42 months). Clinical data were obtained by chart and radiographic review. Major complications were considered to be deep wound infection, pseudarthrosis, transition syndrome, neurologic deficit, and death. Minor complications considered were asymptomatic instrumentation failure (without loss of correction), instrumentation prominence requiring removal, and proximal or distal junctional segmental kyphosis (5-10 degrees ) or subsequent disc space narrowing of 2-5 mm without clinical symptoms. The patients also completed the AAOS Lumbar/Scoliosis MODEMS questionnaires aimed at assessing pain, function, and satisfaction. RESULTS: Minor complications were comparable in both groups: 4 of 18 (22%) in the primary group and 6 of 26 (23%) in the revision group. Major complications were slightly more frequent in the primary group with five complications in 4 patients (4 of 18 patients) (22%) compared with 3 of 26 patients (12%) in the revision group. The incidence of pseudarthrosis was 22% (4 of 18) for the primary group and 4% (1 of 26) for the revision group (P< 0.14). Forty of 44 patients completed the questionnaires. The primary patients functioned at a slightly higher level after surgery than the revision group. The level of pain was also slightly lower at final follow-up in the primary group. Despite these differences, the revision group had a higher level of patient satisfaction. CONCLUSION: At a minimum 2-year follow-up the late complications were not higher in the revision patients than in the primary group. The rate of major long-term complications, specifically pseudarthroses, was higher in the primary group. Patient satisfaction was higher in the revision patients, probably because they were experiencing a greater level of perceived pain and dysfunction at the time of their reconstruction.

Analysis of titanium mesh cages in adults with minimum two-year follow-up.

STUDY DESIGN: This is a study of 66 consecutive adult patients (ages 20-81 years) with sagittal deformities who underwent surgery in which structural titanium mesh cages were implanted into the anterior column during posterior instrumentation and fusion. Follow-up ranged from 24 to 62 months (mean, 33 months). OBJECTIVES: To assess the complications and outcomes of patients with structural cages implanted into the anterior column. SUMMARY OF BACKGROUND DATA: Structural cages for the anterior column are popular in the treatment of adult spinal disorders. Few studies to determine their efficacy have a minimum 2-year follow-up. METHODS: Sixty-six patients with minimum 2-year follow-up were analyzed for cage, spinal fusion, and instrumentation status. Outcomes were assessed by analysis of responses to questionnaires administered to the patients at latest follow-up. RESULTS: No cage failure or extrusion was observed. The average segmental improvement in lordosis with cage implantation was 11 degrees with a loss of correction of less than 1 degrees at latest follow-up. The readability of plain radiographs for assessment of anterior fusions was better than for posterior fusions. The agreement level for judging spines to be fused was two of three for 78% of the anterior levels and 47% of the posterior levels. The remaining posterior fusion levels were unassessable. No statistical difference was found in outcome between the group of patients with suspected nonfused anterior levels and the group with all levels fused. CONCLUSIONS: Structural titanium mesh cages implanted into the anterior column function appropriately to maintain sagittal correction, with rare radiographic complications. Seventy-eight percent of the anterior levels were judged to be fused by observers examining plain radiographs. The outcome at latest follow-up for patients with suspected nonfused anterior levels was similar to that in the group of patients with fusions rated solid at every level.

Radiographic assessment of anterior titanium mesh cages.

Carbon fiber and titanium cage implantation for anterior column support during spinal fusions is an alternative to the use of more traditional structural allografts and autografts. The authors report instrumentation and cage failure for patients who underwent spinal fusion with structural titanium mesh cages implanted into the anterior column a minimum of 2 years after surgery. They wanted to determine whether plain radiographic techniques can be used to critically assess disk space and corpectomy fusions after implantation of these radioopaque cages. Fifty patients having undergone spinal fusions using structural titanium mesh cages in the anterior column had 99 anterior levels fused with at least 1 (maximum of 2) titanium mesh cage, resulting in a total of 131 cages used. The cages were examined for evidence of settling, migration, or failure. The anterior and posterior instrumentation was assessed for evidence of failure, and the spine was examined for evidence of successful fusion. Radiographic cage settling (>2 mm) into the vertebral body end plates was observed, but cage migration or failure were not. An average lordotic correction of 10 degrees was observed, with loss of correction into kyphosis from immediately after operation to final follow-up averaging 2 degrees. As an average of all reviewers, using a strict radiographic fusion assessment, definite or probable anterior fusion was graded at 81% of the levels, probably not or no at 5% of the levels, and could not be assessed at 14% of the levels. Definite or probable posterior fusion as an average of all reviewers was graded at 44% of the posterior fusion levels, questionable at 4%, no at 5%, and could not be assessed at 47%. The use of anterior-only, posterior-only, or anterior and posterior instrumentation with structural titanium mesh cages in the anterior spine along with proper autogenous bone grafting techniques provided anterior column support with a low rate of radiographic complications. Acceptable anterior spinal fusion rates, as assessed by a consensus agreement of reviewers, were observed primarily by evaluation of the fusion mass around the cages (extracage fusion), because intracage fusion was difficult to assess.

Isocitrate dehydrogenase kinase/phosphatase exhibits an intrinsic adenosine triphosphatase activity.

In Escherichia coli, isocitrate dehydrogenase (IDH) is regulated by reversible phosphorylation. The bifunctional enzyme which catalyzes this phosphorylation cycle, IDH kinase/phosphatase, also exhibits a specific ATPase activity. Mutant derivatives of this protein which are nearly devoid of IDH phosphatase activity retain both IDH kinase and ATPase activity, indicating that ATP hydrolysis does not result from the cyclic phosphorylation of IDH. However, the IDH kinase and ATPase activities of these mutant proteins differ significantly from those of the wild-type IDH kinase/phosphatase expressed from the parental allele. This observation suggest that IDH kinase and IDH phosphatase do not reside on structurally independent domains. In contrast to many enzymes which catalyze kinetically unfavorable side reactions, the maximum velocity of the ATPase substantially exceeded those of IDH kinase and IDH phosphatase. ATP hydrolysis was only partially inhibited by phospho- and dephospho-IDH, with saturating levels of phospho-IDH decreasing the rate of ATP hydrolysis by a factor of approximately 5. Even in the presence of near-saturating concentrations of phospho-IDH, the rate of ATP hydrolysis was 4-fold greater than the rate of the cyclic phosphorylation of IDH.