Yoon Hae Kwak

Tibial Lengthening Over an Intramedullary Nail with Use of the Ilizarov External Fixator for Idiopathic Short Stature

BACKGROUND The details regarding bone formation and complication rates associated with tibial lengthening over an intramedullary nail with use of the Ilizarov external fixator have not been reported, to our knowledge. The purpose of this study was to review our experiences with this procedure, performed in individuals with idiopathic short stature. In addition, we compared the results of lengthening over a nail, in terms of the observed bone formation and the complications, with those of the conventional Ilizarov method. METHODS Eighty-eight tibiae in forty-four individuals with a mean preoperative height (and standard deviation) of 153.7 +/- 7.2 cm were included in the study. Thirty-two tibial lengthening procedures were performed with the conventional method and fifty-six, with a nail. The increase in the length of the tibia, the external fixation index, the healing index, and complications were assessed. Three specific concerns, including mobility during the lengthening procedure, the time interval before the patient could return to previous activities after completion of the lengthening, and physical activities at the time of final follow-up, were also assessed. RESULTS The mean final height was 160.1 +/- 7.0 cm, and the mean gain in tibial length was 6.2 cm (20.0%). There was no difference in the mean gain in tibial length or the healing index between the groups; however, the external fixation index was lower and there were fewer complications per tibia in the group treated with the lengthening over a nail. The individuals treated with lengthening over a nail coped better with outdoor activities during the treatment period than the individuals treated with the conventional Ilizarov method; however, there was no difference in the time until the individual returned to previous activities or in the ability to carry out physical activities at the time of final follow-up between the groups. CONCLUSIONS Tibial lengthening with use of the Ilizarov external fixator over an intramedullary nail results in new bone formation of a quality equal to that obtained with the conventional Ilizarov method; however, it reduces the duration of external fixation and the rate of complications.

Correlation of magnetic resonance diffusion tensor imaging and clinical findings of cervical myelopathy

BACKGROUND CONTEXT Despite significant advances in the development of diagnostic technology, the diagnosis of cervical myelopathy (CM) still remains based on the clinical findings, which do not provide the means for a sufficiently accurate diagnosis. Furthermore, conventional magnetic resonance imaging (MRI) using T1- and T2-weighted sequences lacks sensitivity to detect and characterize spinal cord lesions. Considering these uncertainties, several investigators have assessed the diagnostic value of diffusion tensor imaging (DTI), an advanced MRI technique that measures the diffusion of water molecules. PURPOSE To determine the diagnostic value of DTI in CM in reliably characterizing spinal lesions and in associating them with the clinical findings. STUDY DESIGN/SETTING Prospective cohort study. PATIENT SAMPLE Fifteen CM patients and five healthy volunteers without a history of neurological disorders or of symptoms as controls. OUTCOME MEASURES Symptoms and signs of CM were evaluated by the use of a modified Japanese Orthopedic Score and the other clinical findings. T2-weighed MRI was used to note the number of compressed levels. Diffusion tensor imaging results were measured according to two parameters, fractional anisotropy (FA) and apparent diffusion coefficient (ADC), at anterior, lateral, and posterior regions of interest (ROIs) in each of five cervical vertebrae, C3-C7. METHODS On diagnosis of CM by clinical evaluation and findings from T2-weighted MRI, the 15 subjects were assigned to two subgroups based on complaints, symptoms, and signs. The nine subjects who had typical CM symptoms such as motor weakness, gait disturbance, clumsiness of the hands, and unilateral hypesthesia were assigned to the paralysis subgroup. The other six subjects, whose main symptom was pain and who had vague signs of upper motor neuron injury despite a definitive finding of CM by T2-weighted MRI, were assigned to the pain subgroup. Once assignments had been made, subjects underwent DTI done by the use of the same scanner as for T2-weighted MRI. Results of DTI for each subgroup and controls were averaged, and the mean was used for comparisons. Diffusion tensor imaging results from the paralysis subgroup were sorted into affected and unaffected sides according to the presence or the absence of symptoms. RESULTS The paralysis subgroup and the pain subgroup had similar findings from T2-weighted MRI on presentation. The paralysis subgroup had statistically significantly decreased FA values in the anterior and lateral ROIs on the affected side and in the anterior ROIs on the unaffected side, compared with controls. The paralysis subgroup also had statistically significantly increased ADC values in the anterior ROIs of the affected side, compared with controls. The pain subgroup showed significantly increased ADC values in anterior, lateral, and posterior ROIs. CONCLUSIONS Use of DTI to quantitatively compare compression in the cervical spinal cords of CM subjects and healthy controls explained individual differences in the clinical findings in the subjects. These findings even applied to CM subjects whose compressed spinal cords looked similar on conventional T2-weighted MRI. Therefore, DTI provided more accurate and reliable information than did conventional T2-weighted MRI about the relationship between spinal cord structure and clinical presentation of CM. Based on our DTI findings, we hypothesized that different clinical findings in CM are attributable to the stage of progression and the severity of pathologic change at presentation. We anticipate that the use of DTI to quantify the extent of myelopathological changes in CM could be more reliable than any other existing diagnostic tools and might provide invaluable information about selecting the optimal treatment for CM and predicting surgical outcomes and prognosis.

Ankle Valgus Deformity Secondary to Proximal Migration of the Fibula in Tibial Lengthening with Use of the Ilizarov External Fixator

BACKGROUND Ankle valgus deformity secondary to proximal migration of the fibula following an Ilizarov tibial lengthening has not been discussed in detail in the literature. The purposes of this study were to determine the underlying mechanism of and to identify factors associated with proximal migration of the fibula that caused ankle valgus deformity after an Ilizarov tibial lengthening. METHODS We reviewed the outcome of seventy-four bilateral Ilizarov tibial lengthenings for short stature in thirty-seven patients. The mean age at the time of surgery was 21.7 years (range, thirteen to thirty-one years), and the mean duration of follow-up was forty-five months. Proximal migration of the fibula was assessed with changes in the malleolar tip distance. A valgus change of ≥ 5° in the tibiotalar angle was regarded as ankle valgus deformity following tibial lengthening. RESULTS The average length gain was 6.9 cm (range, 4.7 to 11.5 cm), and the average lengthening index was 1.5 mo/cm. Valgus deformity developed in six ankles (8%) and fibular nonunion developed in ten (14%). Proximal migration of the lateral malleolus of ≥ 5 mm was related to valgus talar tilting. Bifocal tibial lengthening, rapid distraction rate of the fibula (>1 mm per day), and development of a fibular nonunion were factors associated with proximal migration of the distal end of the fibula of ≥ 5 mm, which suggests that regenerated bone of poor quality in the distraction gap may cause proximal migration of the distal end of the fibula following tibial lengthening. CONCLUSIONS Proximal migration of the distal end of the fibula following tibial lengthening may occur even with the use of an Ilizarov ring fixator. This migration seems to be caused by collapse of regenerated bone of poor quality or fibular nonunion. Proximal migration of ≥ 5 mm is associated with the risk of valgus talar tilting. Surgeons should consider earlier intervention with bone-grafting if there are conditions that compromise regenerated bone formation in the fibular distraction gap, such as can occur with extensive tibial lengthening by bifocal corticotomy.

Is cervical lordosis relevant in laminoplasty

BACKGROUND CONTEXT Laminoplasty aims to decompress the spinal cord and stabilize the cervical spine in patients with multilevel cervical lesions. Not every patient with cervical compressive myelopathy is a good candidate for laminoplasty. Most studies recommend that neutral or kyphotic alignments are contraindications for laminoplasty. However, cervical sagittal alignment does not have a strong and consistent effect on the clinical outcomes of laminoplasty. Moreover, many reports on the effect of cervical sagittal alignment did not designate the ideal definition of alignment and used different definitions of lordosis. PURPOSE To identify the effect of preoperative cervical alignment according to two different definitions after midline splitting double-door laminoplasty. STUDY DESIGN Retrospective cohort study. PATIENT SAMPLE From August 2008 to September 2010, 58 patients were diagnosed with cervical myelopathy and treated with midline splitting double-door laminoplasty. OUTCOME MEASURES The clinical results were assessed with the modified Japanese Orthopedic Association (JOA) score, neck disability index (NDI), and visual analog scale (VAS) and were compared to analyze the rate of change between preoperative and postoperative values. Postoperative radiological results at the final follow-up examinations were compared between groups to obtain the change in range of motion and sagittal alignment. METHOD The effect of cervical alignment on JOA, NDI, and VAS scales and also on change of alignment and change of range of motion (ROM) at the final follow-up examinations was analyzed statistically between two groups according to two different definitions such as Toyama classification and Cobb angle. RESULTS No difference was found between the two groups according to Toyama classification in terms of the postoperative improvement rate of the modified JOA score (p=.086), decreasing rate of the VAS (p=.940) or NDI (p=.211), postoperatively. Additionally, no difference was found for the decreasing rate of ROM (p=.427) or sagittal alignment (p=.864) based on the radiological evaluation results. Also, there was no difference between two groups according to Cobb angle in terms of the modified JOA score (p=.743), VAS (p=.548), or NDI (p=.32), postoperatively. Additionally, no difference was found for the ROM (p=1.000) or sagittal alignment (p=.440) based on the radiological evaluation results. CONCLUSIONS Despite nonlordosis cervical sagittal alignment, double-door laminoplasty would be effective for patients with cervical myelopathy because of cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament. Furthermore, sagittal alignment is not the absolute and sole factor that surgeons should consider when determining the optimal treatment strategy.

Use of allograft in skeletally immature patients for calcaneal neck lengthening osteotomy.

Purpose To date, there have been no studies evaluating the usefulness of allograft as a substitute for autograft in calcaneal neck lengthening osteotomy. This retrospective study examined the results of calcaneal neck lengthening osteotomy using allograft for pathologic flatfoot deformity in children and adolescents with various neuromuscular diseases. Materials and Methods 118 feet in 79 children treated surgically between Mar 2000 and July 2005 were reviewed. The mean age at the time of the operation was 9 + 3 years (range, 3 - 17 years) and follow-up averaged 15.4 months (range, 13 - 21 months) postoperatively. Talo-1st metatarsal angle, talo-calcaneal angle, calcaneal pitch were measured before and after operation and bony union was estimated. Results Bony union was noted at the latest follow-up and there were no postoperative complications such as reduction loss, infection, nonunion, delayed union or graft loss during the follow-up period in all but one foot. All radiographic indices were improved postoperatively in all cases. Conclusion Our results indicate that use of allograft in calcaneal neck lengthening osteotomy is a useful option for correction of the planovalgus deformity in skeletally immature patients whose enough autobone can not be obtained.

Analysis of factors that may influence range of motion after cervical disc arthroplasty.

BACKGROUND CONTEXT Cervical artificial disc replacement is increasingly becoming popular among spine surgeons. Cervical disc arthroplasty aims to afford spinal stability and then balance this with flexibility. One of the fundamental benefits from performing cervical arthroplasty instead of fusion is preservation of motion in both the functional spinal unit (FSU) and the overall cervical spine. Eventually, preservation of segmental motion is believed to prevent the development of adjacent segment degeneration. But to justify its use, disc replacement prosthesis must demonstrate actual motion in vivo and preserve range of motion (ROM) after surgery as long as it allows. Without preservation of motion, disc prosthesis becomes just a functional arthrodesis equivalent. PURPOSE The purpose of this study was to analyze the possible factors affecting cervical spine ROM after single-level cervical disc arthroplasty. STUDY DESIGN/SETTING This is a retrospective radiological study of patients with symptomatic single-level cervical disc disorder who received the cervical disc prosthesis (Bryan Cervical Disc Prosthesis; Medtronic Sofamor Danek, Memphis, TN, USA). PATIENT SAMPLE Procedure was performed in 39 patients. OUTCOME MEASURES The outcome measures were statistical correlation of possible factors and ROM. METHODS We investigated possible factors that could affect cervical ROM after surgical intervention using cervical disc replacement. For this, we focused on two main components, namely, patient factors and technical factors. First, we examined patient factors, such as age, sex, preoperative FSU ROM, and preoperative overall cervical spine (whole cervical spine) ROM. Second, we then investigated technical factors, such as the amount of bone resection, disc insertion angle, and disc insertion depth. Then, our study searched if there was any statistical correlation between these factors and the postoperative cervical ROM. RESULTS Significant correlation was found between the postoperative overall cervical spine ROM and preoperative overall cervical spine ROM (p<.0001, R(2)=0.9062). Postoperative FSU ROM is closely correlated to both the preoperative FSU ROM (p<.0001) and the disc insertion angle (p=.0097). However, no significant correlation was noted between age, sex, disc insertion angle, and disc insertion depth. CONCLUSION Significant correlation was found between the postoperative overall cervical spine ROM and preoperative overall cervical spine ROM. Postoperative FSU ROM is closely correlated to both the preoperative FSU ROM and the disc insertion angle. Careful preoperative evaluation of the patients radiographs and meticulous surgical technique during the surgical procedure could aid in achieving the goals and benefits of cervical disc arthroplasty.

Overlapping intramedullary nailing after failed minimally invasive locked plating for osteoporotic distal femur fractures - Report of 2 cases

Minimally invasive plate osteosynthesis (MIPO) using a locking plate has been widely used for distal femur fractures in the elderly with osteoporosis and yielded favourable results. However, implant failure and subsequent periplate fracture have still occurred owing to the controversy of concepts regarding locked plating. The treatment after failed MIPO in elderly patients is very challenging and has been not yet addressed definitely in the literature, although several options can be considered. We report the successful outcomes of two cases treated with overlapping intramedullary (IM) nailing for implant failure and periplate fracture after MIPO for osteoporotic distal femur fracture, along with simple tips of distal interlocking of IM nail.

Factors influencing functional outcomes in united intertrochanteric hip fractures: a negative effect of lag screw sliding.

The purpose of this study was to investigate the factors influencing functional outcomes in elderly patients with united intertrochanteric fractures treated with hip nails and to ascertain whether decreased femoral offset due to lag screw sliding has a negative effect on functional outcomes in these patients. This retrospective study included 65 patients older than 65 years with united intertrochanteric fractures treated with hip nails. Functional outcomes were assessed using the Short Form-36 (SF-36) and a visual analog scale (VAS) 6 months postoperatively. Mean patient age was 77.8 years (range, 65-90 years); mean follow-up was 20.7 months (range, 12-38 months). More lag screw sliding occurred as bone mineral density (BMD) decreased. It was also greater in unstable fractures and acceptable reduction status. Less accurate reduction and greater lag screw sliding showed significant negative effects on most subscales of the SF-36, especially Physical Functioning and Role Physical. A significant positive correlation was observed between the extent of lag screw sliding and VAS. Lag screw sliding affected by fracture type, reduction quality, and BMD has a negative effect on functional outcomes in elderly patients with united intertrochanteric fractures. Therefore, the preservation of anatomical femoral offset as much as possible is needed to obtain better functional outcome through the minimization of lag screw sliding by more accurate reduction, which is a controllable factor, especially in osteoporotic unstable intertrochanteric fractures.

Altered Synthesis of Cartilage-Specific Proteoglycans by Mutant Human Cartilage Oligomeric Matrix Protein

Background The mechanism by which mutant cartilage oligomeric matrix protein (COMP) induces a pseudoachondroplasia phenotype remains unknown, and the reason why a mutation of a minor protein of the growth plate cartilage causes total disruption of endochondral bone formation has not yet been determined. The current study was performed to investigate the effects of mutated COMP on the synthesis of the cartilage-specific major matrix proteins of Swarm rat chondrosarcoma chondrocytes. Methods The Swarm rat chondrosarcoma chondrocytes transfected with a chimeric construct, which consisted of a mutant gene of human COMP and an amino acid FLAG tag sequence, were cultured in agarose gel. Formation of extracellular proteoglycan and type-II collagen by the cells was evaluated by immunohistochemical staining and measuring the 35S-sulfate incorporation. Results No difference was observed for the detection of type-II collagen among the cell lines expressing mutant COMP and the control cell lines. Histochemical staining of sulfated proteoglycans with safranin-O showed that lesser amounts of proteoglycans were incorporated into the extracellular matrix of the chondrocytes transfected with the mutant gene. 35S-sulfate incorporation into the cell/matrix fractions demonstrated markedly lower radiolabel incorporation, as compared to that of the control cells. Conclusions Mutation of COMP has an important impact on the processing of proteoglycans, rather than type-II collagen, in the three-dimensional culture of Swarm rat chondrosarcoma chondrocytes.

The impact of coronal alignment of device on radiographic degeneration in the case of total disc replacement

BACKGROUND CONTEXT Numerous studies have been conducted on the importance of radiographic parameters after a total disc replacement (TDR). Most of them have focused on sagittal alignment. There has been no research on what influence the coronal alignment or tilting of device has on radiographic parameters. PURPOSE The aim was to investigate the influences of coronal tilting of device on radiographic parameters and degeneration. STUDY DESIGN/SETTING This was a prospective comparative study. PATIENT SAMPLE A total of 180 patients with single-level cervical disc disease who underwent TDR were included. OUTCOME MEASURES Overall and functional spinal unit (FSU) sagittal range of motion (ROM), coronal alignment (or tilting) of device, and postoperative radiographic degeneration (RD) were analyzed. METHODS Static anteroposterior, lateral X-rays, and dynamic lateral radiographs were assessed preoperatively, postoperatively, at 1.5, 3, 6, 9, 12, 18, 24 months, and every 6 months thereafter until final follow-up. A correlation with various parameters that could result in RD was investigated, For this, the patients were divided into two groups (Group I, RD; Group II, no RD) and subdivided into Group I-A (<5°; low coronal tilt) and Group I-B (≥5°; high coronal tilt) to analyze whether coronal tilting of device was correlated with RD. RESULTS No statistical differences were found in preoperative overall and FSU ROM, postoperative overall and FSU ROM between Groups I and II. However, there was significant difference in coronal tilting of device between Groups I (4.50±2.83°) and II (2.04±1.15°; p=.001). There were no significant differences in preoperative overall and FSU ROM, postoperative overall and FSU ROM between Group I-A and I-B. But, RD incidence rate at surgical segment in Group I-A was 23.1%, whereas that in Group I-B was 75.0% (p=.001). The influence level of a difference in the incidence rate was found to be 10.0 of the odds ratio. Radiographic degeneration incidence rate at adjacent levels in Group I-A was 8.33%, whereas that in Group I-B was 25.0% (p=.013). The influence level of a difference in the incidence rate was found to be 3.67 of the odds ratio. CONCLUSIONS It is considered that maintaining appropriate coronal alignment of device is important in long-term success after a cervical TDR.