Pullout Strength of Pedicle Screws

Study Design: A cadaveric biomechanical study designed to test the pullout strength of pedicle screws. Objective: To evaluate the pullout strength of redirected pedicle screws with a larger diameter following lateral wall breach, redirected pedicle screws of the same diameter following medial wall breach, and redirected pedicle screws with a larger diameter following medial wall breach. Summary of Background Data: Screw malposition is one of the main pitfalls of inserting pedicle screws. Intraoperatively a malpositioned screw is re-directed and inserted along the correct axis. Methods: Forty-seven vertebrae (T9–L5) were harvested from 8 fresh cadaveric spines. The 18 pedicle screws that breached the lateral wall were then removed and redirected using a pedicle screw of 1 mm larger in diameter. The 16 pedicle screws that had breached the medial wall were then removed and redirected using a pedicle screw of the same diameter. The other 13 pedicle screws that had breached the medial wall were then removed and redirected using a pedicle screw of 1 mm larger in diameter. The pullout strength was measured. Results: Following lateral wall breach, mean pullout strength for the larger redirected screws was 46.9% greater than that of the correctly aligned screws. Following medial wall breach, mean pullout strength for the redirected screws of the same diameter was 20.6% less than that of the correctly aligned screws. Mean pullout strength for the larger pedicle screws following medial wall breach was 27.3% more than that of the correctly aligned screws. Conclusion: Redirected pedicle screws of larger diameter after a lateral or medial pedicle breach show recovery of pullout strength. However, the pullout strength of redirected pedicle screws of the same diameter after a medial pedicle breach is significantly less than that of correctly aligned screws.Redirected pedicle screws of larger diameter after a lateral or medial pedicle breach show the recovery of pullout strength. However, the pullout strength of redirected pedicle screws of the same diameter after a medial pedicle breach is significantly less than that of correctly aligned screws

コウコウセイ アスリート ヨウツイ ツイカンバン ヘルニア ニ タイシテ ノ ケイヒテキ ナイシキョウ シカ ツイカンバン ヘルニア テキシュツジュツ PED ノ タンキ セイセキ

Lumbar disc herniation is usually due to age related degeneration of annulus fibrosus, although sometimes lumbar disc herniation is caused by trauma, lifting injuries or sport activities. Percutaneous endoscopic lumbar discectomy （PED） is performed under local anesthesia and is only required ８-mm skin incision. The surgeon accesses the lateral lumber disc “so called transforaminal approach” using small camera and instruments that fit through the ７．５mm diameter cannula. PED is minimally invasive lumbar discectomy, especially for back muscle injury. Although PED is minimally invasive lumbar discectomy for athletes, it is unknown PED available for high school athletes. The purpose of this study is evaluation of the results after PED for high school athletes. Four male and one female high school athletes with lumbar disc herniation were performed PED surgery under local anesthesia. Mean age is １６．５ years old. Time to return to play own sports and the incidents of recurrence of lumber disc herniation were investigated. Visual Analog Scale （VAS） for low back pain at the latest examination was measured. All cases were able to perform the surgery under local anesthesia and return to own sports. Post operative course were successful. Time to return to their sport was from ４ to ８ weeks after surgery. The mean VAS （out of １０） for low back pain at latest examination was１．０. PED for high school athletes is the minimal invasiveness and good short-term clinical results

Spontaneous Rupture and Hemorrhage of Myxopapillary Ependymoma of the Filum Terminale : A Case Report and Literature Review

We present a rare case of acute onset cauda equina syndrome caused by a ruptured myxopapillary ependymoma with accompanying hemorrhage. A 26-year-old healthy woman developed muscle weakness and sensory disturbances in her bilateral lower extremities. Magnetic resonance imaging showed a huge mass from the L1 body to the L2-3 disc level. She was able to ambulate with crutches after the tumor was successfully removed. To prevent recurrence, she received whole brain and spinal cord radiation. No sing of recurrence were detected at the 8 month follow up

ヒト腱・靭帯のプロテオーム解析 : 結合組織における不溶性細胞外マトリックスの可溶化と解析

Connective tissues such as tendon, ligament and cartilage are mostly composed of extracellular matrix (ECM). These tissues are insoluble, mainly due to the highly cross-linked ECM proteins such as collagens. Difficulties obtaining suitable samples for mass spectrometric analysis render the application of modern proteomic technologies difficult. Complete solubilization of them would not only elucidate protein composition of normal tissues but also reveal pathophysiology of pathological tissues. Here we report complete solubilization of human Achilles tendon and yellow ligament, which is achieved by chemical digestion combined with successive protease treatment including elastase. The digestion mixture was subjected to liquid chromatography-mass spectrometry. The low specificity of elastase was overcome by accurate mass analysis achieved using FT-ICR-MS. In addition to the detailed proteome of both tissues, we also quantitatively determine the major protein composition of samples, by measuring peak area of some characteristic peptides detected in tissue samples and in purified proteins. As a result, differences between human Achilles tendon and yellow ligament were elucidated at molecular level

脊椎椎弓根スクリュー誤挿入後,再挿入を行った際の引き抜き強度についての研究

Screw malposition, such as lateral wall breach or end-plate breach, is one of the main pitfalls of inserting pedicle screws. Methods: From 17 fresh spines 54 vertebrae were harvested. In each vertebra on one pedicle the screw was inserted correctly down the axis of the pedicle, while on the other pedicle the screw was inserted to breach the lateral wall or the end-plate. The 18 pedicle screws that breached the lateral wall were then removed and re-directed along the correct axis of the pedicle. The 18 pedicle screws that breached the end-plate were removed and re-directed along the correct axis of the pedicle. The 18 other pedicle screws that had breached the end-plate were not removed. The pullout force of pedicle screws was measured. Results: 1) The mean pullout strength for the re-directed screws following lateral wall breach was 24.0% less as compared to the correctly aligned screws; 2) The mean pullout strength for the re-directed screws following end-plate breach was 23.3% less as compared to the correctly aligned screws; 3) The mean pullout strength for the pedicle screws end-plate breach was 7.6% less as compared to the correctly aligned screws. Conclusion: The pullout strength of re-directed pedicle screws after either a lateral pedicle breach or end-plate breach is significantly less than the pullout strength of correctly aligned screw. A pedicle screw that is not re-directed after end-plate breach is weaker than a pedicle screw correctly aligned, however the difference is not significant

Surgery Related Complications in Percutaneous Endoscopic Lumbar Discectomy under Local Anesthesia

The minimally invasive percutaneous endoscopic discectomy (PED) as the postero-lateral approach with the local anesthesia was started in the late 20th century. The procedure only requires 8 mm of skin incision ; thus, it is the least invasive disc surgery presently. The surgery related complications were reviewed in the initial 100 cases from the single surgeon (K.S., first author). Two cases showed exiting nerve irritation, and complained of leg paresthetic pain for 6 to 12 weeks after the surgery (2.0%). The symptoms got better with medicines. One showed post-surgical epidural hematoma, and required surgical removal of the mass (1.0%). Two cases complained neck pain during surgery (2.0%). Surgeons would be aware of the specific complications for the postero-lateral approach of PED procedure

Reconstruction of chronic Achilles tendon rupture using the semitendinosus tendon : a case report

Achilles tendon rupture is a common trauma requiring surgical management. For chronic Achilles tendon rupture in particular, reconstructive surgery is desirable and several methods have been described. Here we present a case of chronic Achilles tendon rupture reconstructed using the semitendinosus tendon because of the difficulty in pulling down the proximal stump to reach the distal stump and due to an insufficient margin for hooking a suture to the distal stump. Postoperatively, the patient had a fully functional tendon and resumed his normal activities of daily living. Using this surgical technique, we expect favorable outcomes in cases of Achilles tendon rupture

Efficacy of hip arthroscopy in the diagnosis and treatment of synovial osteochondromatosis : a case report and literature review

Here we report a rare case of synovial osteochondromatosis of the hip and provide a brief review of the literature. A 37-year-old woman was referred to our department with a 3-year history of right hip pain. At initial consultation, she complained of pain upon standing and when sitting down, occasional pain at rest and nocturnal pain in the right hip, and worsening of the pain at premenstruum. The range of motion of the affected hip was totally limited by pain. Plain radiography revealed a slightly calcified (or ossified) lesion at the acetabular fossa of the right hip. Computed tomography showed clusters of loose bodies filling the acetabular fossa. Synovial osteochondromatosis was suspected and she underwent hip arthroscopic surgery. Complete resection was performed using the lateral and anterior portals. Postoperatively, her symptoms disappeared entirely and she was discharged 4 days after surgery. The patient regained full range of motion of the right hip and follow-up CT revealed no remaining loose bodies in the right hip. Hip arthroscopy is considered to be effective for the diagnosis and treatment of synovial osteochondromatosis of the hip and is minimally invasive

State of the Art : Elbow Arthroscopy : Review of the Literature and Application for Osteochondritis Dissecans of the Capitellum

Elbow arthroscopy has become a safe and effective treatment option for a number of elbow disorders. The most rewarding and successful indication is the removal of loose bodies. Loose bodies are often a result of osteochondritis dissecans (OCD) of the　capitellum, and arthroscopy in this case is useful for performing debridement, thereby eliminating the need for a more extensive open procedure associated with complications. In this review, we describe our arthroscopic technique for OCD of the capitellum. We usually conduct arthroscopy in the supine position, and use 2.9-mm arthroscopes of 30°and 70°. The 70°arthroscope provides a greater operative field than the 30°arthroscope. Arthroscopic treatment for OCD may require 2 anterior and 2 posterior portals. Loose bodies are commonly found in the radial fossa, coronoid fossa, and in the olecranon fossa. Once the loose bodies are removed, all unstable cartilage of the capitellum lesion is removed to create a stable bed. If any sclerotic changes to the lesion bed are observed, we create microfractures in the lesion bed. The most significant complication in arthroplasty is neurovascular injury. However, we have never experienced this devastating complication, which can be avoided by paying careful attention to detail

The state of the art in arthroscopic hip surgery

Hip arthroscopy is among the most rapidly evolving arthroscopic techniques in the last decade and offers the benefits of being both a minimally invasive procedure and an excellent diagnostic tool. Improvements in instrumentation and surgical skills have advanced our ability to accurately diagnose and treat various conditions of the hip joint, and hip arthroscopy has elucidated several pathologies that cause disabling symptoms. Many of these conditions were previously unrecognized and left untreated. The indications for hip arthroscopy include the management of early osteoarthritis, synovial disorders (e.g., synovial osteochondromatosis), labral tears, chondral lesions, and femoroacetabular impingement (FAI), which is increasingly recognized as a disorder that can lead to the development of early cartilage and labral injury. A better understanding of hip arthroscopy, including the anatomy, improved surgical techniques, indications, and complications of the procedure, is essential for its success. This review article discusses the state of the art of arthroscopic hip surgery