A new minimal-invasive approach for total hip replacement in sheep.

BACKGROUND: Over the last 50 years arthroplasty became the gold-standard treatment for disabling conditions of the coxofemoral joint. Variations of anterior, lateral, and dorsal incision have been applied, but as each approach requires the incision and reflection of various muscles to gain adequate exposure of the joint results are still controversial. OBJECTIVE: The purpose of this study was to develop a minimal-invasive, tissue-sparing approach in sheep with reduced risks in animal testing. METHODS: 12 mature sheep underwent hip surgery as part of a study to evaluate a hip resurfacing system. In line with the preliminary cadaveric tests a modified, minimal-invasive, musclepreserving surgical approach was sought after. RESULTS: We developed a surgical approach to the coxofemoral joint in sheep using only blunt tissue dissection after skin incision without any limitations in joint exposure or increased blood loss/duration of surgery. CONCLUSION: Even though limitations occur and femoral orientation in sheep differs from man, joint forces have similar relative directions to the bone with similar bony and vascular anatomy. Therefore, this minimal-invasive muscle preserving approach might be a safe and comparable alternative in still inevitable animal testing.

Use of a High-Fidelity Training Simulator for Minimally Invasive Lumbar Decompression Increases Working Knowledge and Technical Skills Among Orthopedic and Neurosurgical Trainees.

STUDY DESIGN: Prospective comparative study. OBJECTIVE: To quantify the educational benefit to surgical trainees of using a high-fidelity simulator to perform minimally invasive (MIS) unilateral laminotomy for bilateral decompression (ULBD) for lumbar stenosis. METHODS: Twelve orthopedic and neurologic surgery residents performed three MIS ULBD procedures over 2 weeks on a simulator guided by established AO Spine metrics. Video recording of each surgery was rated by three blinded, independent experts using a global rating scale. The learning curve was evaluated with attention to technical skills, skipped steps, occurrence of errors, and timing. A knowledge gap analysis evaluating participants' current vs desired ability was performed after each trial. RESULTS: From trial 1 to 3, there was a decrease in average procedural time by 31.7 minutes. The cumulative number of skipped steps and surgical errors decreased from 25 to 6 and 24 to 6, respectively. Overall surgical proficiency improved as indicated by video rating of efficiency and smoothness of surgical maneuvers, most notably with knowledge and handling of instruments. The greatest changes were noted in junior rather than senior residents. Average knowledge gap analysis significantly decreased by 30% from the first to last trial (P = .001), signifying trainees performed closer to their desired technical goal. CONCLUSION: Procedural metrics for minimally invasive ULBD in combination with a realistic surgical simulator can be used to improve the skills and confidence of trainees. Surgical simulation may offer an important educational complement to traditional methods of skill acquisition and should be explored further with other MIS techniques.

Lumbar spinal stenosis - surgical outcome and the odds of revision-surgery: Is it all due to the surgeon?

BACKGROUND: Surgical decompression is the intervention of choice for lumbar spinal stenosis (LSS) when non-operative treatment has failed. Apart from acute complications such as hematoma and infections, same-level recurrent lumbar stenosis and adjacent-segment disease (ASD) are factors that can occur after index lumbar spine surgery. OBJECTIVE: The aim of this retrospective case series was to evaluate the outcome of surgery and the odds of necessary revisions. METHODS: Patients who had undergone either decompressive lumbar laminotomy or laminotomy and spinal fusion due to lumbar spinal stenosis (LSS) between 2000 and 2011 were included in this analysis. Demographic, perioperative and radiographic data were collected. Clinical outcome was evaluated using numeric rating scale (NRS), the symptom subscale of the adapted version of the german Spinal Stenosis Measure (SSM) and patient-sreported ability to walk. RESULTS: Within the LSS- cohort of 438 patients, 338 patients underwent decompression surgery only, while instrumentation in addition to decompression was performed in 100 cases (22.3%). 38 patients had prior spinal operations (decompression, disc herniation, fusion) either at our hospital or elsewhere. Thirty-five intraoperative complications were documented with dural tear with CSF leak being the most common (33/35; 94.3%). Postoperative complications were defined as complications that needed surgery and differentiated between immediate postoperative complications (⩽ 3 weeks post operation) and complications that needed revisions surgery at a later date. Within all patients 51 revisions were classified as immediate complications of the index operation with infections, neurological deficits and hematoma being the most common. Within this group only 22 patients had fusion surgery in the first place, while 29 were treated by decompression. Revision surgery was indicated by 53 patients at a later date. While 4 patients decided against surgery, 49 revision surgeries were planned. 28 were performed at the same level, 10 at the same level plus an adjacent level, and 10 were executed at index level with indications of adjacent level spinal stenosis, adjacent level spinal stenosis plus instability and stand-alone instability. Pre- operative VAS score and ability to walk improved significantly in all patients. CONCLUSIONS: While looking for predictors of revision surgery due to re-stenosis, instability or same/adjacent segment disease none of these were found. Within our cohort no significant differences concerning demographic, peri-operative and radiographic data of patients with or without revision wer noted. Patients, who needed revision surgery were older but slightly healthier while more likely to be male and smoking. Surprisingly, significant differences were noted regarding the distribution of intraoperative and early postoperative complications among the 6 main surgeons while these weren't obious within the intial index group of late revisions.

Is the EOS imaging system as accurate as conventional radiography in grading osteoarthritis of the knee?

OBJECTIVES: The EOS imaging system allows for the acquirement of long-leg radiographic images in a standing position without stitching artifacts or projection bias and at a comparatively low-radiation-dose exposure. The aim of our study was to compare the accuracy of EOS images of the lower limb to conventional radiographs (CR) of the knee in a.p. view for the grading of osteoarthritis (OA). METHODS: One hundred forty-two patients who had undergone EOS of the lower limb and radiography of the knee on the same day were included. For the grading of OA, the Kellgren and Lawrence score (KL) score and the Osteoarthritis Research Society International (OARSI) system were used. Additionally, the joint space was measured and compared between the two techniques. EOS images were compared to conventional anteroposterior radiographs of the knee which constitute the gold standard. RESULTS: Measurements of the joint space showed very good intra-class correlation. The calculated weighted kappa for the KL score of EOS versus CR was excellent. The comparison of the different parameters of the OARSI score showed superb weighted kappa scores between 0.9 and 0.96 (α < 0.001) for the parameters osteophytes and joint space narrowing. The parameter deformity showed a good agreement between EOS and radiographs (sensitivity 93.6%; specificity 100%). For the sclerosis parameter, an overall sensitivity of 71.3% and a specificity of 99.3% were calculated. CONCLUSIONS: The grading of OA using the KL score as well as the quantitative assessment of joint space width can be performed on EOS images in a.p. view as reliably as on CR. Subchondral sclerosis of the lateral and medial femur condyle or tibia is sometimes not as evident on EOS images. KEY POINTS: • Grading of OA may be performed as reliably with EOS images in a.p. view as with conventional radiographs in a.p. view. • EOS can be safely used for primary assessment of osteoarthritis of the knee. • In the preoperative setting for knee replacement surgery, conventional radiographs in two or three planes of the knee should still be acquired in addition to long-leg EOS images.

Metrics Development for Minimal Invasive Unilateral Laminotomy for Bilateral Decompression of Lumbar Spinal Stenosis With and Without Spondylolisthesis by an International Expert Panel.

STUDY DESIGN: Prospective study. OBJECTIVES: To develop, operationally define, and seek consensus from procedure experts on the metrics that best characterize a reference approach to the performance of a minimally invasive unilateral laminotomy for bilateral decompression (ULBD) for lumbar spinal stenosis. METHODS: A Metrics Group consisting of 3 experienced spine surgeons (2 neurosurgeons, 1 orthopedic surgeon), each with over 25 years of clinical practice, and an educational expert formed the Metrics Group that characterized a lumbar decompression surgery for spinal stenosis as a "reference" procedure. In a modified Delphi panel, 26 spine surgeons from 14 countries critiqued these metrics and their operational definitions before reaching consensus. RESULTS: Performance metrics consisting of 6 phases with 42 steps, 21 errors, and 17 sentinel errors were identified that characterize the procedure. During the peer review, these were evaluated, modified, and agreed. CONCLUSIONS: Surgical procedures can be broken down into elemental tasks necessary for the safe and effective completion of a reference approach to a specified surgical procedure. Spinal experts from 16 countries reached consensus on performance metrics for the procedure. This metric-based characterization can be used in a training curriculum and also for assessment of training and performance in clinical practice.

Tandem Microscopic Slalom Technique: The Use of 2 Microscopes Simultaneously Performing Unilateral Laminotomy for Bilateral Decompression in Multilevel Lumbar Spinal Stenosis.

STUDY DESIGN: Technical note, retrospective case series. OBJECTIVE: Lumbar stenosis can be effectively treated using tubular unilateral laminotomy for bilateral decompression (ULBD). For multilevel stenosis, a multilevel ULBD through separate, alternating crossover approaches has been described as the "slalom technique." To increase efficacy, we introduced this approach with 2 microscopes simultaneously. METHODS: We collected data on 13 patients, with multilevel lumbar stenosis, operated at our institution between 2015 and 2016 by the aforementioned technique. We assessed surgical time (ST), estimated blood loss (EBL), complications, and revision surgeries. Furthermore, we provide a stepwise instruction for performing the tandem microscopic slalom technique in a safe and efficient manner. RESULTS: The mean age of the patients was 68 ± 8 years. The ST per level was 68 ± 19 minutes with an EBL per level of 39 ± 30 mL. We had no intraoperative complications and none of our patients required a revision surgery during a mean follow-up of 12 months. CONCLUSIONS: We have shown that this technique is feasible and can be performed safely for multisegmental lumbar spinal stenosis with minimal tissue trauma and low EBL. Furthermore, randomized controlled studies with a larger sample size may be necessary to drive any final conclusions.

Effects of Whole Body Vibration Therapy and Classic Physiotherapy on Postural Stability in People With Back Pain: A Randomized Trial.

STUDY DESIGN: This 2-step prospective randomized parallel trial evaluated postural stability in 65 back pain participants (61.6±7.9 y) and 50 nonback pain participants (61.2±8.6 y) in a first step using the MFT-S3-Check. In a second step, postural stability and questionnaires were evaluated in back pain participants before and after therapy with either whole body vibration therapy or classic physiotherapy. OBJECTIVE: The first aim was to investigate whether the MFT-S3-Check is suitable to evaluate differences in postural stability in back pain and nonback pain participants. The second aim was to evaluate the effect of whole body vibration therapy and classic physiotherapy on postural stability and the influence of depressive symptoms and pain. SUMMARY OF BACKGROUND DATA: Objective bodily measurement values in chronic back pain are rare; therefore, the evaluation of effectiveness of different therapies is difficult. METHODS: Postural stability was investigated using stability-, sensorimotor-, and symmetry indexes, in standing and seated positions with the MFT-S3-Check. The following standard questionnaires were used to investigate pain and depressive symptoms: HADS, ODI, NASS, SF-36. RESULTS: No significant difference in postural stability was found between back pain participants and the nonback pain group. None of the two training concepts in back pain participants was superior, concerning postural stability and pain. Both treatments showed positive effects, with significant improvements in postural stability in the classic physiotherapy group. Depressive symptoms had a significant correlation with pain intensity in back pain participants. CONCLUSIONS: The MFT-S3-Check could not find a significant difference in postural stability between the back pain and nonback pain group in the study setting. Postural stability improved after treatment.

Slow correction of severe spastic hyperlordosis in an adult by means of magnetically expandable rods.

BACKGROUND: We describe a case of severe and progressive lumbar hyperlordosis (160°) in a 28-year-old female university student with cerebral palsy. Her main complaints were abdominal wall pain and increasing inability to sit in her custom wheelchair. METHOD: When deciding on our opinion about the most promising treatment strategy, we contemplated slow continued correction by means of percutaneously expandable magnetic rods (MAGEC) after the index surgery as a key component of a satisfactory correction in this severe and rigid curve. After an initial radical release and partial correction, a release and correction procedure was required for the bilateral hip flexion contracture. A final in situ posterior fusion was performed as a second spinal procedure, once the desired final correction at 66° of lumbar lordosis was achieved. RESULT: Three years after the completion of surgery, the patient has a stable clinical and radiological result as well as a solid posterior fusion on CT. CONCLUSION: This is the first case published in which percutaneous magnetic distraction was successfully used in an adult patient.

"One and a half" minimally invasive transforaminal lumbar interbody fusion: single level transforaminal lumbar interbody fusion with adjacent segment unilateral laminotomy for bilateral decompression for spondylolisthesis with bisegmental stenosis.

Symptomatic lumbar spondylolisthesis is commonly accompanied by spinal stenosis in multiple segments. These pathologies are routinely treated by multilevel decompression and instrumented fusion. However, it was hypothesized that a minimally invasive surgery (MIS) fusion in the unstable segment combined with a unilateral laminotomy for bilateral decompression (ULBD) in the adjacent stenotic segment is a biomechanically feasible alternative to a two-level fusion and superior to open laminectomy adjacent to a fused segment. This concept has demonstrated success in a recently published biomechanical cadaver study performed by our group. The present article offers a detailed step by step technical description for an MIS-TLIF (transforaminal lumbar interbody fusion) with adjacent ULBD.

"Kissing Nail Technique" for the exchange of intramedullary implants in adjacent peri-implant fractures.

One third of the people aged 65 years and over fall every year, and 1-5% of these falls result in a fracture. For these people, history of fracture and surgery become a risk factor for recurrent falls. In osteoporotic patients, repeated fractures often require several osteosynthetic procedures within a short time frame. Despite the lack of biomechanical studies, clinical experience suggests that additional fractures adjacent to implants occur because of the difference in stiffness between the metallic implant and the osteoporotic bone. This requires customized fixation techniques to ensure stability. The technique was first performed in an 81-year old female patient presenting with a dislocated proximal femoral fracture at the tip of a previously implanted distal femoral nail (DFN), and non-union of the old fracture. For this technique, the DFN was advanced until it passed the proximal fracture, thereby reducing both fractures, while a lateral femoral nail (LFN), extra-long and 3 mm thicker than the DFN, was introduced and advanced distally. The LFN was implanted in a "kissing nail technique," meaning the tips of the two nails were touching each other, and all fracture fragments were held in functional reduction. The DFN was slowly pulled backwards and fragment stability was maintained, while both nails passed the distal non-union. The Kissing Nail Technique allows simple, safe and fast reduction of all instable fragments, precise and easy positioning of the proximal entry point by the retrograde guide wire, a minimally invasive procedure, and stable fixation of a periprosthetic fracture. We found this new customized procedure accommodating to the unique anatomical features of a single patient, that can be applied as a strategy especially for osteoporotic patients with periprosthetic fractures.

An intramedullary capillary hemangioma of the spine with an underlying plasmocytoma.

BACKGROUND CONTEXT: In contrast to vertebral hemangiomas, which are very common within the general population, only 3% to 5% of patients with plasma cell dyscrasia show a single osteolytic bone lesion due to plasma cell infiltration without the evidence of generalized myeloma. The vast majority of these hemangiomas are completely asymptomatic and only discovered incidentally. In rare occasions, representing only 1% to 2% of the known lesions, a locally aggressive subtype can cause problems analogous to the ones triggered by a plasmocytoma, ranging from back pain to vertebral compression fractures to neurologic deficit, resulting from nerve root or spinal cord compression. Both entities are extensively discussed in the literature, but finding both lesions in one is rare if not described for the first time. PURPOSE: To advise colleagues that the differential diagnosis between benign and malignant vertebral tumors can be harder than expected and has to be definitely made to avoid severe consequences for the patient. PATIENT SAMPLE: A 46-year-old healthy man presented to the emergency department with an acute onset of thoracic back pain after a trivial incident. Although his medical history included no known diseases and no history of back pain, plain X-rays raised the clear suspicion of a fracture of T6 that was verified in computed tomography scans. OUTCOME MEASURES: Visual analog scale; neurologic status; tumor recurrence. METHODS: The case of the patient was evaluated retrospectively according to standard procedures, clinical outcome, and in review of the literature. RESULTS: Because there is still controversy about the best treatment (local radiation vs. operation vs. combination) of a solitary skeletal plasmocytoma, no gold standard has been established until now. Especially if a patient needs an emergency operation before all test results are obtained, each surgeon has to decide individually. CONCLUSIONS: Capillary hemangiomas can hide underlying plasmocytomas, which might demand totally different treatment strategies. Although our patient did not match the common criteria for a solitary plasmocytoma, one has to discuss whether a stand-alone decompression and biopsy would have been the emergency treatment of choice. Such a strategy would have reduced the risk of tumor spreading and would have made radiotherapy easier, whereas on the other hand requiring a secondary stabilization procedure later on.

The gel box - a testing device for the characterization of cryo- and radiofrequency lesions employed in interventional pain therapy.

BACKGROUND: Radiofrequency (RF) and cryolesioning are established methods for the therapeutic interruption of sensory nerve supply to facet joints and other painful musculoskeletal structures. The varying clinical success rates of these treatments have - among other technical issues - been attributed to the small size of these lesions combined with the limited precision in placing them. Since there are 2 different physical methods for lesioning and a wide range of probes and lesion generators available, it is likely that the lesions generated by them may be of different size. OBJECTIVES: We sought to devise an experimental setup that would allow for the reproducible and comparable evaluation of the size of cryo and RF lesions as they are being used in interventional pain therapy. METHODS: A wide range of potential media was evaluated for this purpose. Based on technical specifications, as well as on preliminary testing, a specific agar agar gel with a gel point of between 32 degrees C and 35 degrees C and a melting point of between 80 degrees C and 85 degrees C was selected for these experiments. Two different testing containers were constructed from transparent acrylic: one with a volume of 1,500 mL and the other with a volume of 12 mL. Each of them allows for the introduction of a cryo or a RF probe and 2 bundles of thermoelements into the gel volume. A water bath was used to maintain the gels at 37 degrees C and bundled, ultrafine NiCr-Ni thermoelements type K were used for measuring the isotherms. A series of RF and cryolesions were performed within these experimental setups to evaluate their suitability for the comparative testing of cryo and RF probes and generators. RESULTS: Both testing setups generated reproducible results and proved to be suitable for measuring RF as well as cryolesions. Visual observation of the lesions was better with the small testing container and rewarming / recooling after performing a cryo / RF lesion was more rapid with the smaller gel volume. LIMITATIONS: Our setup allows for the comparative measurement of RF and cryolesions, but it cannot simulate the realities within living tissue. While convection as a confounding factor was excluded by use of a gel, capillary perfusion and the specific characteristics of different tissues cannot be simulated. CONCLUSIONS: The testing setup described in this manuscript can serve for the comparative and reproducible study of RF and cryolesions that are commonly used in interventional pain therapy.

[Subtrochanteric end-to-side valgus osteotomy for severe infantile coxa vara]. / Die subtrochantäre End-zu-Seit-Valgisation zur Therapie der schweren kindlichen Coxa vara.

OBJECTIVE: Healing of the frequently associated femoral neck pseudarthrosis. Restoration of a proper length-tension relationship of muscles and lever arms of the hip. Regulation of forces acting on the femoral neck. Realignment of the leg length. Adjustment of the greater trochanter apophysis to allow regular growth. INDICATIONS: Severe infantile coxa vara (CCD [collodiaphyseal] angle