Percutaneous Endoscopic Thoracic Discectomy: Posterolateral Transforaminal Approach

OBJECTIVE: Development of diagnostic tools has resulted in early detection of thoracic disc herniations(TDH) even when the herniated disc is soft in consistency. In some of the cases, it is considered better not to opt for surgical treatment due to the unduly high morbidity and potential complications associated with conventional approaches. The authors have applied percutaneous endoscopic thoracic discectomy(PETD) technique to soft TDHs in order to avoid the morbidity associated with conventional approaches. METHODS: Eight consecutive patients (range, 31 to 75 years) with soft lateral or central TDH (from T2-3 to T11-12) underwent PETD between May 2001 and June 2004. The patient was positioned in a prone position with intravenous sedation and local anesthetic infiltration. The authors introduced a cannula into the thoracic intervertebral foramen using endoscopic foraminoplasty technique. Discectomy was performed with mechanical tools and a laser under continuous endoscopic visualization and fluoroscopic guidance. Functional status was assessed preoperatively and postoperatively using the Oswestry Disability Index(ODI). RESULTS: The mean ODI scores improved from 52.8 before the surgery to 25.8 at the final follow-up. In cases of myelopathy, long tract signs showed improvement. The mean operative time was 55 minutes, and no patient required conversion to open surgery. CONCLUSION: The technique allows a smaller incision and less morbidity. Soft TDH is amenable to this minimally invasive approach in selected patients with myeloradiculopathy.

Percutaneous Endoscopic Interlaminar Discectomy for L5-S1 Disc Herniation: Axillary Approach and Preliminary Results

OBJECTIVE: The purpose of this study was to describe a surgical technique of axillary approach of percutaneous endoscopic interlaminar discectomy for L5-S1 disc herniation and its preliminary results. METHODS: From July 2002 to September 2003, 101 patients with lumbar radiculopathy due to L5-S1 disc herniation, who were treated by percutaneous interlaminar endoscopic discectomy, were retrospectively reviewed. There were 57 males and 44 females with a mean age of 44.8 years (range, 18 to 62 years). The surgery consisted of needle insertion into the epidural space via the interlaminar space, sequential dilatation, and endoscopic discectomy through the axillary area of the S1 root. RESULTS: The mean follow-up period was 14.5 months and the average surgical time was 41 min. According to the modified Macnab criteria, 44 patients (43.6%) had excellent outcomes, 49 (48.5%) had good results and only 8 (7.8%) had fair or poor outcomes. Four patients had a revision microdiscectomy due to incomplete removal of disc fragment. There were no major complications related to this surgical approach. CONCLUSION: Axillary approach of percutaneous endoscopic interlaminar discectomy is safe and effective procedure for the treatment of L5-S1 disc herniation. It combines the advantages of MED and conventional percutaneous endoscopic discectomy.

Radiological Evaluation of Percutaneous Endoscopic Lumbar Discectomy: A Three-Year Follow-Up Study

PURPOSE: We wanted to analyze the radiological changes of the patients who underwent percutaneous endoscopic lumbar discectomy (PELD) for treating soft disc herniation. MATERIALS AND METHODS: We retrospectively reviewed 30 patients (32 cases) who were observed for a minimum of 3 years after they underwent PELD. The authors investigated the postoperative radiological changes after PELD and the related clinical outcomes. All the patients received plain X-rays, CT and MRI both preoperatively and at the final follow-up. The radiological parameters were evaluated, including the disc height, the disc signal intensity, the subchondral marrow signal intensity, the sagittal plane instability and the facet joint osteoarthritis. RESULTS: The average amount of removed disc was 1.363 g and a significant correlation was detected between the narrowing of disc height and the amount of removed disc. Although the disc height and the disc height ratio were significantly decreased (-0.97 mm and 86.9%, respectively), the angle of sagittal rotation was well maintained. There were 18 (56.3%) cases of disc signal changes, six cases (18.8%) of subchondral marrow signal changes, and three cases (9.4%) of facet joint osteoarthritis. The success rate was 90.6%. CONCLUSION: Although disc height narrowing was observed, there was no postoperative instability and the overall clinical outcome was satisfactory. Our results show that PELD is a useful and minimal invasive procedure for the selected patients who are suffering with lumbar disc herniation.

Radiologic Measurement of Pelvic Sagittal Incidence and Lordosis in Young Korean Women / 대한정형외과학회잡지

PURPOSE: To determine the normative data for the pelvic morphology parameters in the young Korean female population. MATERIALS AND METHODS: Young Korean female patients in 20s and 30s who had visited the outpatient clinic for a first attack acute sprain underwent a telephone interview at a minimum of 1 year after their last hospital visit. Those who had recovered completely and had no back-related complaints were selected for the pelvic lordosis angle (PRS1)and pelvic angle of incidence (AOI)measurements (n=40 each age group). RESULTS: There was no age difference in both parameters. The PRS1 in the young female population was 38.7+/-8.3 degrees (range: 13.6-52.9 degrees and the AOI was 48.5 +/-9.4 degrees(range: 30.5-74.7 degrees, which shows a close correlation between the two parameters (correlation coefficient, r=-0.965). The linear regression equation obtained is as follow; Equation I: PRS1=79.909-0.850 x AOI, Equation II: AOI=90.902-1.096xPRS1 (linear regression analysis, p=0.000, R2 =0.931). CONCLUSION: The data obtained from the study may be used for future studies related to the sagittal spinopelvic balance.

The Influence of Fixation Rigidity on Intervertebral Joints - An Experimental Comparison between a Rigid and a Flexible System

OBJECTIVE: Spinal instrumentation without fusion often fails due to biological failure of intervertebral joints (spontaneous fusion, degeneration, etc). The purpose of this study is to investigate the influence of fixation rigidity on viability of intervertebral joints. METHODS: Twenty pigs in growing period were subjected to posterior segmental fixation. Twelve were fixed with a rigid fixation system(RF) while eight were fixed with a flexible unconstrained implant(FF). At the time of the surgery, a scoliosis was created to monitor fixation adequacy. The pigs were subjected to periodic radiological examinations and 12pigs (six in RF, six in FF) were euthanized at 12-18months postoperatively for analysis. RESULTS: The initial scoliotic curve was reduced from 31+/-5degrees to 27+/-8degrees in RF group (p=0.37) and from 19+/-4degrees to 17+/-5degrees in FF group (p=0.21). Although severe disc degeneration and spontaneous fusion of facet joints were observed in RF group, disc heights of FF group were well maintained without major signs of degeneration. CONCLUSION: The viability of the intervertebral joints depends on motion spinal fixation. Systems allowing intervertebral micromotion may preserve the viability of intervertebral discs and the facet joint articular cartilages while maintaining a reasonably stable fixation.

Early Stress Fracture of the Pelvic Ring Following Proximal Extension of an Instrumented Lumbosacral Fusion to Treat Junctional Kyphosis

We report a case of early stress fracture of the pelvic ring following an extension of a multilevel instrumented lumbosacral fusion in an osteopenic female. Surgeons should be aware of possibilities of pelvic complications in osteopenic patients with lumbosacral arthrodesis and should take care when harvesting iliac bone graft.

The Effect of Segmental Pedicle Screw Instrumentation on Actively Growing Spine: A Long-term Experimental Study

OBJECTIVE: Pedicle screw is gaining popularity in pediatric deformities. However, biological response of actively growing spine to rigid pedicle screw fixation remains unclear. The objective of this study is to determine the biological response of growing spine to rigid segmental fixation. METHODS: Twelve mini pigs in actively growing period were subjected to posterior segmental screw -rod instrumentation spanning nine levels and creation of experimental scoliosis. There was no attempt of posterior arthrodesis. The pigs were subjected to periodic radiological examinations and were euthanized at 18 months for analysis. RESULTS: There was no significant fixation failure despite conspicuous growth of the animals. Initial scoliosis of 31+/-5degrees was reduced to 27+/-8degrees at 18 months, but there was no statistical significance (p=0.37). Though there was no change in length of the implant construct, the vertebrae within the instrumented section showed mean longitudinal growth of 6+/-3 mm (p=0.000). The growth occurred at expense of the disc spaces that progressively narrowed with time. On necropsy, the instrumented region was completely fused posteriorly with crossing of the osseous traberculae across the former facet joints. Intervertebral discs were severely atrophic in all the discs with occasional spontaneous fusion. CONCLUSION: Even in the actively growing spine, the force of growth does not overcome the fixation offered by segmental pedicle screws. Longitudinal growth occurs at the expense of the joint spaces and leads to spontaneous intervertebral fusion. Our results may explain the favorable outcomes in pedicle fixations in pediatric population, showing little implant failure or nonunion.

Percutaneous Endoscopic Lumbar Discectomy for the Treatment of Far Lateral Lumbar Disc Herniation

OBJECTIVE: There are few reports on the clinical outcomes of the percutaneous endoscopic lumbar discectomy(PELD) with laser for the treatment of far lateral lumbar disc herniation. The objective of this study is to assess the safety and efficacy of the PELD with laser for the treatment of far lateral lumbar disc herniation. METHODS: The clinical records of 42 patients who had far lateral lumbar disc herniation and underwent PELD with laser between January 1996 and August 2002 were analyzed retrospectively. There were 24(57.1%) males and 18(42.9%) females, with a mean age of 53(range, 26-73) years. The surgical procedure was performed via a posterolateral approach after induction of a local anesthesis. The clinical outcomes were measured with MacNabO s criteria. The mean follow-up period was 38(range, 5-77) months. RESULTS: Clinical outcomes were revealed as follows: excellent in 28 patients(66.7%); good in 11(26.2%); fair in 2(4.7%); and poor in 1(2.4%). Therefore, the percentage of successful(excellent and good) outcomes was 92.9%. There was no statistically significant variation in the success rates according to age and operation level(p>0.05). Before the introduction of the high resolution endoscope, the success rate was 90.3% but after upgrading to the high resolution endoscope, the success rate was 100%, and there was a statistically significant variation in the success rate(p<0.05). In all cases, there was no complication or recurrence. CONCLUSION: As a minimally invasive surgery, PELD with laser is a safe and efficacious procedure for the treatment of far lateral disc herniation.

FKBP-12 Exhibits an Inhibitory Activity on Calcium Oxalate Crystal Growth in Vitro

Urolithiasis and calcium oxalate crystal deposition diseases are still significant medical problems. In the course of nephrocalcin cDNA cloning, we have identified FKBP-12 as an inhibitory molecule of calcium oxalate crystal growth. lambdagt 11 cDNA libraries were constructed from renal carcinoma tissues and screened for nephrocalcin cDNA clones using anti-nephrocalcin antibody as a probe. Clones expressing recombinant proteins, which appeared to be antigenically cross-reactive to nephrocalcin, were isolated and their DNA sequences and inhibitory activities on the calcium oxalate crystal growth were determined. One of the clone lambdagt 11 #31-1 had a partial fragment (80 bp) of FKBP-12 cDNA as an insert. Therefore, a full-length FKBP-12 cDNA was PCR-cloned from the lambdagt 11 renal carcinoma cDNA library and was subcloned into an expression vector. The resultant recombinant FKBP-12 exhibited an inhibitory activity on the calcium oxalate crystal growth (Kd=10(-7) M). Physiological effect of the extracellular FKBP-12 was investigated in terms of macrophage activation and proinflammatory cytokine gene induction. Extracellular FKBP-12 failed to activate macrophages even at high concentrations. FKBP-12 seems an anti-stone molecule for the oxalate crystal deposition disease and recurrent stone diseases.

Characterization of a Species-specific Antigen in Rickettsia typhi

Murine typhus is an acute febrile illness caused by Rickettsia typhi. It is one of the four major acute febrile illnesses in Korea during autumn. To study a species-specific antigen of R. typhi, two clinical isolates (87-91 and 87-100) and two reference strains (VR-144 and VR-738) were analyzed by mouse antisera and monoclonal antibodies (MAbs). On SDS- polyacrylamide gel electrophoresis (PAGE), R. typhi showed major antigen bands of 135, 80, 75, 64, 47, 22, and 19 kDa and these bands differed with those of other species. On Western blot analysis, the MAbs reacting only with R. typhi could only detect 135 kDa protein. The 135 kDa protein appeared to be the species-specific antigen. Other MAbs showing cross-reactivity with R. prowazekii reacted with 135 kDa protein in fresh culture supernatant of R. typhi infected host cell. However, the cross-reacting antibody did also react with smaller protein bands, most of which seem to be degradation products of the 135 kDa protein since they increase in old protein stocks purified from R. typhi harvested from infected host cell. These suggest that 135 kDa protein is unstable and the R. typhi specific epitopes are located at the regions of 135 kDa protein that are removed when the protein is degraded. The 135 kDa protein or its specific and stable recombinant protein would serve an important target for the development of vaccine and specific diagnostic antigen.

Study on the Production and Function of Macrophage Migration Inhibitory Factor ( MIF ) : Effect of Recombinant MIF and MIF cDNA on the Induction of Cytokine mRNA / 대한면역학회지

In order to study the functions of migration inhibitory factor (MIF) as macrophage activating cytokine and to investigate the possibility of MIF cDNA as gene therapeutic agent or adjuvant, we produced recombinant MIF (rMIF), anti-MIF antibody and pcDNA I plasmid containing mMIF cDNA (mMIF plasmid). We have investigated the effects of recombinant mMIF or mMIF plasmid on the expression of immune response-related gene in the mouse peritoneal macrophage or splenocyte. Recombinant mMIF produced by Baculovirus expression system was biologically active; it increased mRNA expression of tumor necrosis factor (TNF)-a, Interleukin (IL)-1, IL-6, granulocyte monocyte-colony stimulating factor (GM-CSF), nitric oxide synthase (NOS), Fas and Bcl-x when applied to the cultures of mouse peritoneal macrophage. Anti-mMIF antibody blocked these effects of mMIF on macrophage. Plasmid DNA carrying MIF cDNA inoculated into mouse peritoneal cavity also increased mRNA transcriptions from TNF, IL-1, IL-6, IL-12, GM-CSF, NOS genes of peritoneal macrophage. It enhanced proliferation of splenocyte stimulated with phorbol myristate acetate and IL-2 mRNA expression of splenocytes. Frorn these results, we conclude that rMIF is a strong macrophage activating factor and especially MIF plasmid can be used as an immune potentiating DNA drug in gene therapy for cancer or DNA adjuvant in vaccination in future.