The authors have no acknowledgments.

An institutional review board approved this retrospective study (IRB 00060819) of deidentified prospectively collected data.The protocol followed the guidelines approved by the human institutional review board of Adventist Health Lodi Memorial. A written informed consent was obtained from the patients before the procedure.
NOTE: As a representative patient, the clinical course of a 78-year-old male with left hip pain is described. His symptoms included a 2 year history of left groin pain aggravated by activity, night pain not adequately relieved by anti-inflammatory medication, and limitations of daily activities. The Oxford Hip Score at his initial clinic visit was 22 points, and the Hip Disability and Osteoarthritis Outcome Score (HOOS Junior) was 53 points. X-rays revealed primary left hip osteoarthritis (Figure 1).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/63948/63948fig01.jpg" /> 
Figure 1: AP radiograph of the pelvis focused low on the symphysis. The left hip demonstrates typical characteristics of end-stage osteoarthritis. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63948/63948fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
1. Diagnosis, assessment, and plan
<ol>
	<li>Left hip osteoarthritis 
	NOTE: Due to failed conservative treatment, the patient was offered left total hip replacement using the ABMS approach.
	<ol>
		<li>Use the AP-Pelvis x-ray with the 2.5 cm radiographic calibration marker for preoperative planning (Figure 2).</li>
		<li>Measure the distance from the trochanteric fossa to the planned femoral neck resection to restore equal leg length. Fit adequate component sizes to the bony contours to restore femoral offset.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63948/63948fig02.jpg" /> 
Figure 2: Planning THA. The planning of left THA begins with calibrating the radiograph to the metal ball of 2.5 cm diameter. Next, the preoperative leg length difference is measured (0.7 mm in this example). The appropriately sized acetabular component (blue) is positioned to restore the center of rotation. The appropriately sized femoral component with the ideal femoral offset (green) is positioned within the proximal femur to correct for any leg length difference. The distance between the trochanteric fossa and the planned femoral neck resection is measured (5.9 mm in this example). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63948/63948fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
2. Surgical preparation
<ol>
	<li>Starting 5 days before surgery, ask the patient to perform daily skin cleansing using chlorhexidine washing solution. Before surgery, meet the patient in the preoperative holding area and mark the correct hip side with a skin marker.</li>
	<li>After the induction of general anesthesia with inhalation anesthetics and the confirmation of its success by the maintenance of stable vital signs, position the patient in a lateral decubitus position with the operated hip facing up. Perform sterile prepping and draping. Cover the exposed skin with iodine-impregnated adhesive.</li>
	<li>Wrap a sterile elastic bandage around assistant 1&#39;s waist to create a belt. The belt serves to hold a sterile mayo-stand cover, which is attached to the belt with two non-penetrating clamps (= kangaroo bag). The kangaroo bag maintains a sterile environment when the leg is dropped behind the patient.</li>
	<li>Position the surgeon in front of the patient and assistant 1 and assistant 2 behind the patient. Position assistant 1 more distal than assistant 2 to maneuver the leg during surgery.</li>
	<li>Mark the incision:
	<ol>
		<li>Palpate and mark the proximal border or greater trochanter (GT) and the anterior border of the proximal femur. Palpate the anterior border of the gluteus medius (GM) fascia, which is tighter than the fascia overlying the tensor fasciae latae muscle.</li>
		<li>Starting 2 cm distal to the GT, make a line along the anterior border of the proximal femur and then slightly turn anterior along the anterior border of the GM fascia, stopping 6 cm proximal to the GT. The incision length is 8 cm.</li>
	</ol>
	</li>
</ol>
3. Surgical procedure
<ol>
	<li>Instruct assistant 1 to abduct the hip. Incise the skin sharply with a #10-blade following the previously made skin mark. Cut down to the fascia with a knife and use a clean lap sponge to expose the fascia.</li>
	<li>The fascia is pierced by a bundle of vessels (= perforating vessels).&#160;Identify these perforating vessels as they pierce through the fascia. These vessels locate the interval between the GM and tensor fasciae latae (TFL). Distally open the fascia parallel to the orientation of the fascial fibers, and curve anteriorly at the mid-portion of the incision, staying posterior to the perforating vessels.</li>
	<li>Use finger palpation at the greater trochanter to dissect the muscle plane between the TFL anteriorly and the gluteus muscles posteriorly. Run a finger along the GM toward the GT. Then, let the finger drop anteriorly into the space between the GM and TFL. Once the finger is in the space, palpate the femoral neck and posterior portion of the femoral neck by elevating the gluteus medius and minimus posteriorly.</li>
	<li>While assistant 1 is holding the hip abducted, place a curved Hohmann retractor (Nr. 17) over the posterior neck outside the capsule to retract the glutei muscles. Then, place a straight Hohmann retractor (Nr. 7) over the anterior neck outside the capsule under the TFL and the reflected head of the rectus femoris tendon.</li>
	<li>Instruct assistant 1 to slightly externally rotate the hip and make an H-shaped capsulotomy using electrocautery with the bar of the H longitudinally along the femoral neck. Ensure that the distal line of the H is far lateral connecting the tip of the GT and medially around the neck to release the capsule and clean out the trochanteric fossa and intertrochanteric ridge.</li>
	<li>Using electrocautery, go through the entire capsule proximally toward the head and acetabular rim, which is felt as a step with an electrocautery tip. At the acetabular rim, turn the electrocautery 90&#176; and release the capsule along the acetabular rim medially and laterally.</li>
	<li>Reposition the retractors underneath the capsule with the assistant holding the leg in abduction. While assistant 1 increases the external rotation and extension, make a subcapital femoral neck cut oblique from proximal to distal to facilitate the lift of the distal femur once the cut is complete.</li>
	<li>Hold the anterior retractor (Nr. 7 retractor) and, with a key elevator positioned at the osteotomy site, level the femoral neck into the surgical field while assistant 1 hyperextends the hip to &#34;dislodge&#34; the osteotomy. Instruct assistant 1 to place the leg in the kangaroo bag and externally rotate the hip so that the patella is pointing upward and the tibia is perpendicular to the floor.</li>
	<li>Reposition the Nr. 17 retractor over the GT and clean up the trochanteric fossa from the soft tissue using electrocautery.</li>
	<li>Instruct assistant 1 to adduct the hip so that the femoral neck is elevated more out of the wound. Identify the femoral neck cut at the planned level distal to the trochanteric fossa. Ideally, use a template to mark out the neck cut using electrocautery. Then, perform a neck cut using an oscillating saw.</li>
	<li>Cut the medial neck first and then proceed to the lateral neck, paying attention not to violate the GT. Remove the free bone piece of the femoral neck with an osteotome and grasper.</li>
	<li>Remove the Hohmann retractors, and instruct assistant 1 to place the leg out of the bag in a neutral position on the mayo stand to allow hip abduction and slight flexion.</li>
	<li>Place Nr. 15 or Nr. 17 retractors over the posterior acetabulum. The Nr. 15 retractor is wider than the Nr. 17 retractor but with comparable shape and curvature. Then, place the Nr. 7 retractor over the anterior acetabulum. Push through the capsule with the spike.</li>
	<li>Remove the femoral head with the Hohmann retractor and grasper. Push on the inferior part of the head to dislodge it superiorly. Then, use a grasper to remove the head. Remove the labrum using a long knife, and incise the inferior capsule if it is in the hemisphere of the acetabulum.</li>
	<li>Ream the acetabulum to an appropriate size, starting 1 mm smaller than the planned cup diameter. Then, insert the final acetabular component in 40&#176; abduction and 10&#176;-15&#176; anteversion. Insert the final polyethylene liner by manually placing it within the acetabular component and then impacting the liner in the acetabular component to engage the locking mechanism.</li>
	<li>While assistant 1 places the leg in the kangaroo bag and externally rotates the hip to 90&#176;, place a two-prong retractor under the postero-medial aspect of the femoral neck and the Nr. 17 retractor over the GT. Then, instruct assistant 1 to extend and adduct the hip.</li>
	<li>If needed, perform release along the anterior portion of the GT to deliver the femur out of the wound. Then, open the proximal femur with a box cutter and canal finder.</li>
	<li>Broach to an appropriate size and length and place the final stem with templated offset.</li>
	<li>Perform a trial reduction with a trial head. To reduce the hip, instruct assistant 1 to apply slight traction and internally rotate the hip while the surgeon uses a head-pusher to guide the ball into the socket. Check the hip for anterior and posterior stability. Place the Nr. 17 retractor over the posterior acetabulum to visualize the hip. Perform a shuck test in longitudinal and lateral traction.</li>
	<li>To dislocate the hip, place a bone hook around the neck, and instruct assistant 1 to apply traction and external rotation. Remove the trial head. Irrigate the cup, insert the final head, and reduce the hip.</li>
	<li>Replace the Nr. 17 retractor outside the capsule. Reapproximate the capsule with a nonabsorbable suture.</li>
	<li>Repair the gluteal fascia with a synthetic braided absorbable suture while the leg is in slight abduction and external rotation. Close the subcutaneous tissue with a 2-0 braided absorbable suture and skin with sterile skin staples.</li>
</ol>

<ol>
	<li>Melman, W. P., Mollen, B. P., Kollen, B. J., Verheyen, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=First+experiences+with+the+direct+anterior+approach+in+lateral+decubitus+position:+Learning+curve+and+1+year+complication+rate.">First experiences with the direct anterior approach in lateral decubitus position: Learning curve and 1 year complication rate.</a> Hip International. 25 (3), 251-257 (2015).</li><li>Rottinger, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+MIS+anterolateral+approach+for+THA.">The MIS anterolateral approach for THA.</a> Orthopade. 35 (7), 708-715 (2006).</li><li>Bertin, K. C., R&#246;ttinger, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anterolateral+mini-incision+hip+replacement+surgery:+A+modified+Watson-Jones+approach.">Anterolateral mini-incision hip replacement surgery: A modified Watson-Jones approach.</a> Clinical Orthopaedics and Related Research. 429, 248-255 (2004).</li><li>Civinini, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+anterior-based+muscle-sparing+approach+to+the+hip:+The+&amp;#34;other&amp;#34;+anterior+approach+to+the+hip.">The anterior-based muscle-sparing approach to the hip: The &amp;#34;other&amp;#34; anterior approach to the hip.</a> International Orthopaedics. 43 (1), 47-53 (2019).</li><li>De Geest, T., Fennema, P., Lenaerts, G., De Loore, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adverse+effects+associated+with+the+direct+anterior+approach+for+total+hip+arthroplasty:+A+Bayesian+meta-analysis.">Adverse effects associated with the direct anterior approach for total hip arthroplasty: A Bayesian meta-analysis.</a> Archives of Orthopaedic and Trauma Surgery. 135 (8), 1183-1192 (2015).</li><li>Christensen, C. P., Karthikeyan, T., Jacobs, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Greater+prevalence+of+wound+complications+requiring+reoperation+with+direct+anterior+approach+total+hip+arthroplasty.">Greater prevalence of wound complications requiring reoperation with direct anterior approach total hip arthroplasty.</a> The Journal of Arthroplasty. 29 (9), 1839-1841 (2014).</li><li>Leiberman, J. R., Berry, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Advanced Reconstruction: Hip 2. , (2018).</li><li>Delanois, R. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Rottinger+approach+for+total+hip+arthroplasty:+Technique,+comparison+to+the+direct+lateral+approach+and+review+of+literature.">The Rottinger approach for total hip arthroplasty: Technique, comparison to the direct lateral approach and review of literature.</a> Annals of Translational Medicine. 5, 31 (2017).</li><li>Martin, R., Clayson, P. E., Troussel, S., Fraser, B. P., Docquier, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anterolateral+minimally+invasive+total+hip+arthroplasty:+A+prospective+randomized+controlled+study+with+a+follow-up+of+1+year.">Anterolateral minimally invasive total hip arthroplasty: A prospective randomized controlled study with a follow-up of 1 year.</a> The Journal of Arthroplasty. 26 (8), 1362-1372 (2011).</li><li>Laffosse, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Learning+curve+for+a+modified+Watson-Jones+minimally+invasive+approach+in+primary+total+hip+replacement:+Analysis+of+complications+and+early+results+versus+the+standard-incision+posterior+approach.">Learning curve for a modified Watson-Jones minimally invasive approach in primary total hip replacement: Analysis of complications and early results versus the standard-incision posterior approach.</a> Acta Orthopaedica Belgica. 72 (6), 693 (2006).</li><li>Chen, D., Berger, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Outpatient+minimally+invasive+total+hip+arthroplasty+via+a+modified+Watson-Jones+approach:+Technique+and+results.">Outpatient minimally invasive total hip arthroplasty via a modified Watson-Jones approach: Technique and results.</a> Instructional Course Lectures. 62, 229-236 (2013).</li><li>Rottinger, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimally+invasive+anterolateral+surgical+approach+for+total+hip+arthroplasty:+early+clinical+results.">Minimally invasive anterolateral surgical approach for total hip arthroplasty: early clinical results.</a> Hip International. 16, 42-47 (2006).</li><li>de Jong, L., Klem, T. M., Kuijper, T. M., Roukema, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+minimally+invasive+anterolateral+approach+versus+the+traditional+anterolateral+approach+(Watson-Jones)+for+hip+hemiarthroplasty+after+a+femoral+neck+fracture:+an+analysis+of+clinical+outcomes.">The minimally invasive anterolateral approach versus the traditional anterolateral approach (Watson-Jones) for hip hemiarthroplasty after a femoral neck fracture: an analysis of clinical outcomes.</a> International Orthopaedics. 42 (8), 1943-1948 (2018).</li><li>M&#252;ller, M., Tohtz, S., Dewey, M., Springer, I., Perka, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+of+reduced+muscle+trauma+through+a+minimally+invasive+anterolateral+approach+by+means+of+MRI.">Evidence of reduced muscle trauma through a minimally invasive anterolateral approach by means of MRI.</a> Clinical Orthopaedics and Related Research. 468 (12), 3192-3200 (2010).</li><li>Kawarai, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Does+the+surgical+approach+influence+the+implant+alignment+in+total+hip+arthroplasty?+Comparative+study+between+the+direct+anterior+and+the+anterolateral+approaches+in+the+supine+position.">Does the surgical approach influence the implant alignment in total hip arthroplasty? Comparative study between the direct anterior and the anterolateral approaches in the supine position.</a> International Orthopaedics. 41 (12), 2487-2493 (2017).</li><li>Batailler, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Total+hip+arthroplasty+using+direct+anterior+approach+and+dual+mobility+cup:+safe+and+efficient+strategy+against+post-operative+dislocation.">Total hip arthroplasty using direct anterior approach and dual mobility cup: safe and efficient strategy against post-operative dislocation.</a> International Orthopaedics. 41 (3), 499-506 (2017).</li><li>D'Arrigo, C., Speranza, A., Monaco, E., Carcangiu, A., Ferretti, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Learning+curve+in+tissue+sparing+total+hip+replacement:+Comparison+between+different+approaches.">Learning curve in tissue sparing total hip replacement: Comparison between different approaches.</a> Journal of Orthopaedics and Traumatology. 10 (1), 47-54 (2009).</li><li>Rothwell, A. G., Hooper, G. J., Hobbs, A., Frampton, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+analysis+of+the+Oxford+hip+and+knee+scores+and+their+relationship+to+early+joint+revision+in+the+New+Zealand+Joint+Registry.">An analysis of the Oxford hip and knee scores and their relationship to early joint revision in the New Zealand Joint Registry.</a> The Journal of Bone and Joint Surgery. British Volume. 92 (3), 413-418 (2010).</li><li>Devane, P., Horne, G., Gehling, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxford+hip+scores+at+6+months+and+5+years+are+associated+with+total+hip+revision+within+the+subsequent+2+years.">Oxford hip scores at 6 months and 5 years are associated with total hip revision within the subsequent 2 years.</a> Clinical Orthopaedics and Related Research. 471 (12), 3870-3874 (2013).</li><li>Alexander, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Augmented+reality+for+acetabular+component+placement+in+direct+anterior+total+hip+arthroplasty.">Augmented reality for acetabular component placement in direct anterior total hip arthroplasty.</a> The Journal of Arthroplasty. 35 (6), 1636-1641 (2020).</li></ol>

The authors have nothing to disclose.

Minimally invasive surgery (MIS) has gained interest in all fields of surgery due to the faster recovery, lower blood loss, and improved perioperative pain control. THA has adopted MIS to increase hip stability and enhance post-operative mobilization. The ABMS approach utilizes the muscle interval between the tensor fasciae latae and the gluteus medius muscles but without incising or detaching the muscles and tendons. A surgeon considering transitioning to the ABMS approach would be well advised to attend a cadaver course and ideally be accompanied by the first assistant. This will help them to become familiar with the critical surgical steps9. A few critical steps should be outlined: 1) incising the fascia overlying the GM just posterior to the intermuscular plane of the GM and TFL to avoid unnecessary muscle dissection; 2) adequate capsular release during the initial capsulotomy to help expose the acetabulum and femur; and 3) performing an in situ osteotomy instead of dislocating the hip to reduce the risk of femur fractures10. 
Certain steps in the surgical technique can be modified depending on the surgeon's preference. Performing a capsulectomy instead of a capsulotomy does not influence the post-operative stability and does not add post-operative precautions3. Leg length can be restored by measuring the distance from the trochanteric fossa as described in this protocol or by measuring the distance from the lesser trochanter or the intertrochanteric tubercle9,11. As mentioned in the introduction, the ABMS approach can also be performed in the supine position, which requires a surgical table with the option to hyperextend the hips4.
While in the early phase of adapting to the ABMS approach, considerations can be made to limit patient population by body habitus or preoperative hip deformity; increasing comfort with the surgical technique makes the ABMS approach a generally applicable technique without patient selection restrictions10,12. 
Compared to other approaches, clinical studies evaluating the ABMS approach demonstrate better short-term functional outcomes13, less muscle damage14, reliable implant positioning15, a low dislocation rate16, decreased post-operative pain and narcotic requirements, and finally, a shorter learning curve17. The results from the presented study confirm these results. Also, the learning curve in the present study demonstrated a reduction in surgical time over the first 30 THAs. This finding contrasts with previously published data, which showed a persistently long surgical time9. In agreement with the published literature, the present study confirms that the benefit of a muscle-sparing approach diminishes with longer follow-up9. The 6 month OHS indicates that patients do well regardless of the approach, and the risk of revision after ABMS approach is as low as after PA18,19. Further studies will reveal whether the adjunct of intraoperative technologies like navigation or augmented reality will further improve patient outcomes after ABMS approach THA20.
In conclusion, transitioning from PA to the ABMS approach is associated with a learning curve, which implies an increased risk of periprosthetic femur fractures and prolonged surgery times. After 10 THAs have been performed, the risk of femur fractures diminishes, and the surgical time normalizes after the first 20 THAs. Surgeons interested in providing their patients with faster recovery and avoiding post-operative restrictions might find these results valuable when considering changing their THA approach.

In total hip arthroplasty (THA), the surgical approach serves to visualize the acetabulum and proximal femur and to prepare the acetabulum and proximal femur for safe and stable implantation of the prosthetic components1. An ideal surgical approach in THA provides adequate exposure while minimizing the risk of damage to the muscles, blood vessels, and nerves and the risk of postoperative instability.
The anterior-based muscle-sparing (ABMS) approach in THA utilizes the muscle interval popularized by Sir Reginald Watson-Jones in 19302. The ABMS approach avails itself of the intermuscular plane between the tensor fasciae latae (TFL) and the gluteus medius (GM) to gain access to the hip joint. The abductor muscles are preserved and not detached during this approach. As the ABMS approach is anterior to the GM and to the greater trochanter (GT), it is similar and shares the advantages of the direct anterior approach (DAA)-being muscle sparing. Even though the ABMS approach can be performed with the patient in a supine position, many surgeons prefer the lateral decubitus position based on its original description3.
The ABMS, like the DAA, has multiple operative and early postoperative benefits. The exposure of the acetabulum is excellent, which facilitates optimal positioning of the acetabular component. Functional recovery is faster in the early postoperative period due to there being less muscle damage and, consequently, lower dislocation rates4.
The reported disadvantages of the DAA are damage to the lateral femoral cutaneous nerve (LFCN), the need for a special operating table, wound healing problems, and more limited exposure to the femur5,6. By avoiding these disadvantages, the ABMS has since its introduction in 2004&#160;routinely been utilized in European countries, and has recently attracted more attention in North America3. Motivated by 1) the concept of a muscle-sparing approach, which negates the necessity of post-operative precautions7, 2) the ability to perform the surgery in a lateral decubitus position, which allows stability evaluation maneuvers familiar to a surgeon performing THA through the posterior approach (PA), 3) avoiding intra-operative fluoroscopy8, 4) the increased anatomical distance to the LFCN in comparison to the DA, and 5) the further lateralized incision, which avoids wound-healing complications caused by overhanging soft-tissue, surgeons might decide to transition to the ABMS approach.
However, surgeons considering transitioning to the ABMS approach for THA are concerned about whether transitioning will ultimately improve patient outcomes and about the learning curve associated with the transition. Accordingly, the first cohort of 30 THAs, which were implanted by a single surgeon using the ABMS approach, was analyzed and compared to results gained from 30 THAs implanted by the same surgeon through the PA immediately before the transition. The present study tested 1) whether early patient-reported outcomes improved in the ABMS group in comparison to the PA group and 2) whether the surgical time and complication rate decreased with the number of THAs performed.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>30&#176; Offset Masterloc Broach handle L</td>
			<td>Medacta</td>
			<td>01.10.10.461</td>
			<td></td>
		</tr>
		<tr>
			<td>30&#176; Offset Masterloc Broach Handle R</td>
			<td>Medacta</td>
			<td>01.10.10.460</td>
			<td></td>
		</tr>
		<tr>
			<td>3D Printed Acetabular Component</td>
			<td>Medacta</td>
			<td>01.38.058DH</td>
			<td></td>
		</tr>
		<tr>
			<td>ACE Wrap 6 in</td>
			<td></td>
			<td>140700</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetabular Liner</td>
			<td>Medacta</td>
			<td>01.32.4048HCT</td>
			<td></td>
		</tr>
		<tr>
			<td>AMIS 2.0 Genera Tray</td>
			<td>Medacta</td>
			<td>01.15.10.0294</td>
			<td>Curved cup impactor</td>
		</tr>
		<tr>
			<td>AMIS 2.0 General Tray</td>
			<td>Medacta</td>
			<td>01.15.10.0293</td>
			<td>Screw driver for cup impactor</td>
		</tr>
		<tr>
			<td>Anterior Auxillery</td>
			<td>Medacta</td>
			<td>ALAUX</td>
			<td></td>
		</tr>
		<tr>
			<td>Biolox Ceramic Head</td>
			<td>Medacta</td>
			<td>01.29.214</td>
			<td></td>
		</tr>
		<tr>
			<td>Chloraprep 26 mL</td>
			<td>BD</td>
			<td>301185</td>
			<td></td>
		</tr>
		<tr>
			<td>Drape Mayostand</td>
			<td>Cardianal</td>
			<td>7999</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethibond Size 5</td>
			<td>Ethicon</td>
			<td>103831</td>
			<td></td>
		</tr>
		<tr>
			<td>Femoral Neck Elevator</td>
			<td></td>
			<td>3006</td>
			<td></td>
		</tr>
		<tr>
			<td>Femoral neck elevator</td>
			<td></td>
			<td>01.15.10.0037</td>
			<td></td>
		</tr>
		<tr>
			<td>Ioban</td>
			<td>3M</td>
			<td>15808</td>
			<td></td>
		</tr>
		<tr>
			<td>Ketorolac 30 mg/mL</td>
			<td>SN</td>
			<td>MED00575</td>
			<td></td>
		</tr>
		<tr>
			<td>Masterloc Inst (MLOCINS)</td>
			<td>Medacta</td>
			<td>01.39S.301US</td>
			<td></td>
		</tr>
		<tr>
			<td>Masterlock Femoral Stem</td>
			<td>Medacta</td>
			<td>01.39.408</td>
			<td></td>
		</tr>
		<tr>
			<td>Mpact General (MPACT)</td>
			<td>Medacta</td>
			<td>01.32S.300US</td>
			<td></td>
		</tr>
		<tr>
			<td>Mpact Liner Trial face changing/offset</td>
			<td>Medacta</td>
			<td>01.325.305</td>
			<td></td>
		</tr>
		<tr>
			<td>Mpact Liner Trial face changing/offset</td>
			<td>Medacta</td>
			<td>01.325.305</td>
			<td></td>
		</tr>
		<tr>
			<td>Mpact liner trial flat/hooded</td>
			<td>Medacta</td>
			<td>01.32S.301</td>
			<td></td>
		</tr>
		<tr>
			<td>Mpact liner trial flat/hooded</td>
			<td>Medacta</td>
			<td>01.32S.301</td>
			<td></td>
		</tr>
		<tr>
			<td>Mpact Reamers (MPACT)</td>
			<td>Medacta</td>
			<td>01.32S.101US</td>
			<td>Regular hemi reamers swapped out for Half-Moon Reamers</td>
		</tr>
		<tr>
			<td>Single Prong Acetabular Retractor, Extra Deep</td>
			<td></td>
			<td>6570-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Single Prong Acetabular Retractor, Standard</td>
			<td></td>
			<td>6570</td>
			<td></td>
		</tr>
		<tr>
			<td>Single Prong Broad Acetabular Retractor</td>
			<td></td>
			<td>6320</td>
			<td></td>
		</tr>
		<tr>
			<td>Stapler Kine Proximate Plus 35 W</td>
			<td>Ethicon</td>
			<td>52686</td>
			<td></td>
		</tr>
		<tr>
			<td>Tranexamic acid 1 g</td>
			<td>SN</td>
			<td>MED01071</td>
			<td></td>
		</tr>
		<tr>
			<td>Unger Narrow Hohmann</td>
			<td></td>
			<td>3002</td>
			<td></td>
		</tr>
		<tr>
			<td>Vicryl 1 CTX</td>
			<td>Ethicon</td>
			<td>143836</td>
			<td></td>
		</tr>
		<tr>
			<td>Vicryl 2-0 CT2</td>
			<td>Ethicon</td>
			<td>9174</td>
			<td></td>
		</tr>
	</tbody>
</table>

the transition to an anterior-based muscle sparing approach improves early postoperative function but is associated with a learning curve

Surgeons considering transitioning to an anterior-based approach for THA are concerned about the learning curve and the reported marginal clinical benefit. Accordingly, the first cohort of THAs, which were implanted by a single surgeon using the anterior-based muscle-sparing approach (ABMS), was analyzed. The goal of the study was to test 1) whether patient-reported outcomes improved and 2) whether the complication rate decreased with the number of THAs performed. A retrospective cohort study on the first 30 primary THA cases (27 patients) of one surgeon (January 2021-April 2021) using the ABMS approach was conducted. These 30 THAs were compared to 30 primary THA cases (30 patients) done immediately prior to the transition by the same surgeon (September 2020-December 2020) using the posterior approach (PA). The Oxford Hip Score (OHS), Hip Disability and Osteoarthritis Outcome Score (HOOS Junior), and Forgotten Joint Score (FJS) obtained 6 weeks and 6 months after surgery were compared. In addition, three consecutive groups based on equal numbers of THAs were compared for the incidence of complications and surgery time. At 6 weeks after THA, the OHS was 6 points higher after the ABMS approach (p = 0.0408), and the OHS was comparable at 6 months. The HOOS Junior and FJS were similar at 6 weeks and 6 months after surgery.&#160;In the first 10 THAs using the ABMS approach, one patient had a greater trochanter fracture, and one patient had an intraoperative proximal femur fracture. No further immediate interoperative or postoperative complications occurred. Surgery time significantly reduced with the number of THAs performed. Transitioning from the PA to the ABMS approach is associated with a learning curve, which is limited to the first 20 cases. The effect of improved clinical outcomes is apparent within the early postoperative period. After 6 months, THA patients do well regardless of the approach.

At 6 weeks after THA, the mean OHS was 35 points after the ABMS approach and 29 after the PA (p = 0.0408). The HOOS and FJS did not differ significantly 6 weeks after THA between the ABMS approach and PA. At 6 months after THA, no differences in outcome scores were observed (Table 1).
In the first 10 THAs using the ABMS approach, one patient had a greater trochanter fracture treated with a tension band suture, and one patient had an intraoperative proximal femur fracture treated with a revision cone femoral stem. No further immediate interoperative or postoperative complications occurred. Surgery time significantly reduced with the number of THAs performed from a mean of 113 min for the first 10 patients to a mean of 67 min for the THAs 21-30 (Table 2).
At 6 weeks, the presented patient had an OHS of 42, HOOS Junior of 85, and FJS of 100. The patient used a walking aid for the first 4 days and could return to his desired activities without restrictions 3 weeks after surgery. His post-operative X-rays demonstrated restored leg length and femoral offset (Figure 3).
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/63948/63948fig03.jpg" /> 
Figure 3: Postoperative AP and lateral radiograph. Composite shows the postoperative AP and lateral radiograph of the pelvis and left hip, respectively. Leg length and femoral offset are restored. The position of the acetabular component is within acceptable ranges. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/63948/63948fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="2"></td>
			<td colspan="2">THA approach</td>
			<td></td>
		</tr>
		<tr>
			<td colspan="2"></td>
			<td>ABMS approach</td>
			<td>PA</td>
			<td>Significance</td>
		</tr>
		<tr>
			<td colspan="2">6 weeks after THA</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Oxford hip score (OHS)</td>
			<td rowspan="2">Mean &#177; SD</td>
			<td rowspan="2">35 &#177; 9.7</td>
			<td rowspan="2">29 &#177; 10.7</td>
			<td rowspan="2">p = 0.0481*</td>
		</tr>
		<tr>
			<td>(48 best, 0 worst)</td>
		</tr>
		<tr>
			<td>Hip Injury and osteoarthritis outcome score (HOOS)&#160;</td>
			<td rowspan="2">Mean &#177; SD</td>
			<td rowspan="2">73 &#177; 14.3</td>
			<td rowspan="2">70 &#177; 16.3</td>
			<td rowspan="2">NS, p = 0.3745*</td>
		</tr>
		<tr>
			<td>(100 best, 0 worst)</td>
		</tr>
		<tr>
			<td>Forgotten joint score (FJS)</td>
			<td rowspan="2">Mean &#177; SD</td>
			<td rowspan="2">51 &#177; 29.7</td>
			<td rowspan="2">44 &#177; 30.5</td>
			<td rowspan="2">NS, p = 0.4008*</td>
		</tr>
		<tr>
			<td>(100 best, 0 worst)</td>
		</tr>
		<tr>
			<td colspan="2">6 months after THA</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Oxford hip score (OHS)</td>
			<td rowspan="2">Mean &#177; SD</td>
			<td rowspan="2">44 &#177; 5.3</td>
			<td rowspan="2">44 &#177; 4.6</td>
			<td rowspan="2">NS, p = 0.8879*</td>
		</tr>
		<tr>
			<td>(48 best, 0 worst)</td>
		</tr>
		<tr>
			<td>Hip Injury and osteoarthritis outcome score (HOOS)&#160;</td>
			<td rowspan="2">Mean &#177; SD</td>
			<td rowspan="2">89 &#177; 14.4</td>
			<td rowspan="2">84 &#177; 13.9</td>
			<td rowspan="2">NS, p = 0.3145*</td>
		</tr>
		<tr>
			<td>(100 best, 0 worst)</td>
		</tr>
		<tr>
			<td>Forgotten joint score (FJS)</td>
			<td rowspan="2">Mean &#177; SD</td>
			<td rowspan="2">86 &#177; 23.4</td>
			<td rowspan="2">83 &#177; 25.2</td>
			<td rowspan="2">NS, p = 0.6994*</td>
		</tr>
		<tr>
			<td>(100 best, 0 worst)</td>
		</tr>
		<tr>
			<td>Standard deviation (SD)&#160;</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>*Student&#39;s T-test</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>
Table 1: Comparison between the anterior-based muscle-sparing (ABMS) approach and the posterior approach (PA). The difference in Oxford Hip Score, Hip Disability and Osteoarthritis Outcome Score (HOOS), and Forgotten Joint Score between the anterior-based muscle-sparing (ABMS) approach and the posterior approach (PA) at 6 weeks and 6 months after THA (Student&#39;s T-test*).
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="2"></td>
			<td colspan="3">Groups of ten patients treated with ABMS approach</td>
			<td></td>
		</tr>
		<tr>
			<td colspan="2"></td>
			<td>1&#8211;10 THAs</td>
			<td>11&#8211;20 THAs</td>
			<td>21&#8211;30 THAs</td>
			<td>Significance&#160;</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td>ANOVA</td>
		</tr>
		<tr>
			<td>Surgical Time (min)</td>
			<td>Mean &#177; SD</td>
			<td>113 &#177; 23.4</td>
			<td>104 &#177; 3.2</td>
			<td>67 &#177; 9.2</td>
			<td>p &#60; 0.0001*</td>
		</tr>
		<tr>
			<td colspan="2" rowspan="2">Post-hoc Tukey&#8217;s test</td>
			<td>vs. 11&#8211;20 THAs</td>
			<td>vs. 21&#8211;30 THAs</td>
			<td>vs. 1&#8211;10 THAs</td>
			<td></td>
		</tr>
		<tr>
			<td>NS, p = 0.4169#</td>
			<td>p = 0.0009#</td>
			<td>p &#60; 0.0001#</td>
			<td></td>
		</tr>
		<tr>
			<td>Standard deviation (SD)</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>*ANOVA</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>#Post-hoc Tukey&#8217;s test</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>
Table 2: Mean surgical time. The difference in the mean surgical time across the three patient groups (ANOVA* and post-hoc Tukey&#39;s test#), indicating a learning curve regarding surgical efficiency.

Watch this Scientific Journal Video about The Transition to an Anterior-Based Muscle Sparing Approach Improves Early Postoperative Function but is Associated with a Learning Curve at JoVE.com

The Transition to an Anterior-Based Muscle Sparing Approach Improves Early Postoperative Function but is Associated with a Learning Curve

The anterior-based muscle-sparing approach for total hip arthroplasty (THA) is associated with a learning curve. However, the improved clinical outcome in the early post-operative phase makes the consideration to transition worthwhile.

Surgeons considering transitioning to an anterior-based approach for THA are concerned about the learning curve and the reported marginal clinical ...

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2.5K Views.  University of Würzburg. The anterior-based muscle-sparing approach for total hip arthroplasty (THA) is associated with a learning curve. However, the improved clinical outcome in the early post-operative phase makes the consideration to transition worthwhile. 

Video: The Transition to an Anterior-Based Muscle Sparing Approach Improves Early Postoperative Function but is Associated with a Learning Curve

Assessing Endothelial Vasodilator Function with the Endo-PAT 2000

The endothelium is a delicate monolayer of cells that lines all blood vessels, and which comprises the systemic and lymphatic capillaries. By virtue of the panoply of paracrine factors that it secretes, the endothelium regulates the contractile and proliferative state of the underlying vascular smooth muscle, as well as the interaction of the vessel wall with circulating blood elements. Because of its central role in mediating vessel tone and growth, its position as gateway to circulating immune cells, and its local regulation of hemostasis and coagulation, the the properly functioning endothelium is the key to cardiovascular health. Conversely, the earliest disorder in most vascular diseases is endothelial dysfunction.
In the arterial circulation, the healthy endothelium generally exerts a vasodilator influence on the vascular smooth muscle. There are a number of methods to assess endothelial vasodilator function. The Endo-PAT 2000 is a new device that is used to assess endothelial vasodilator function in a rapid and non-invasive fashion. Unlike the commonly used technique of duplex ultra-sonography to assess flow-mediated vasodilation, it is totally non-operator-dependent, and the equipment is an order of magnitude less expensive. The device records endothelium-mediated changes in the digital pulse waveform known as the PAT ( peripheral Arterial Tone) signal, measured with a pair of novel modified plethysmographic probes situated on the finger index of each hand. Endothelium-mediated changes in the PAT signal are elicited by creating a downstream hyperemic response. Hyperemia is induced by occluding blood flow through the brachial artery for 5 minutes using an inflatable cuff on one hand. The response to reactive hyperemia is calculated automatically by the system. A PAT ratio is created using the post and pre occlusion values. These values are normalized to measurements from the contra-lateral arm, which serves as control for non-endothelial dependent systemic effects. Most notably, this normalization controls for fluctuations in sympathetic nerve outflow that may induce changes in peripheral arterial tone that are superimposed on the hyperemic response.
In this video we demonstrate how to use the Endo-PAT 2000 to perform a clinically relevant assessment of endothelial vasodilator function.

A noninvasive procedure to assess endothelial function is demonstrated using the Endo-PAT 2000.

The endothelium is a delicate monolayer of cells that lines all blood vessels, and which comprises the systemic and lymphatic capillaries. By virtue of ...

In Vivo Canine Muscle Function Assay

We describe a minimally-invasive and reproducible method to measure canine pelvic limb muscle strength and muscle response to repeated eccentric 
contractions. The pelvic limb of an anesthetized dog is immobilized in a stereotactic frame to align the tibia at a right angle to the femur. Adhesive wrap affixes the 
paw to a pedal mounted on the shaft of a servomotor to measure torque. Percutaneous nerve stimulation activates pelvic limb muscles of the paw to either push (extend) or 
pull (flex) against the pedal to generate isometric torque. Percutaneous tibial nerve stimulation activates tibiotarsal extensor muscles. Repeated eccentric (lengthening) 
contractions are induced in the tibiotarsal flexor muscles by percutaneous peroneal nerve stimulation. The eccentric protocol consists of an initial isometric contraction 
followed by a forced stretch imposed by the servomotor. The rotation effectively lengthens the muscle while it contracts, e.g., an eccentric contraction. During 
stimulation flexor muscles are subjected to an 800 msec isometric and 200 msec eccentric contraction. This procedure is repeated every 5 sec. To avoid fatigue, 4 min rest 
follows every 10 contractions with a total of 30 contractions performed.

In Vivo Canine Muscle Function Assay

We describe a minimally-invasive and painless method to measure canine hindlimb muscle strength and muscle response to repeated eccentric contractions.

We describe a minimally-invasive and reproducible method to measure canine pelvic limb muscle strength and muscle response to repeated eccentric 
...

A Methodological Approach to Non-invasive Assessments of Vascular Function and Morphology

The endothelium is the innermost lining of the vasculature and is involved in the maintenance of vascular homeostasis. Damage to the endothelium may predispose the vessel to atherosclerosis and increase the risk for cardiovascular disease. Assessments of peripheral endothelial function are good indicators of early abnormalities in the vascular wall and correlate well with assessments of coronary endothelial function. The present manuscript details the important methodological steps necessary for the assessment of microvascular endothelial function using laser Doppler imaging with iontophoresis, large vessel endothelial function using flow-mediated dilatation, and carotid atherosclerosis using carotid artery ultrasound. A discussion on the methodological considerations for each of the techniques is also presented, and recommendations are made for future research.

The present article describes the methodological considerations for several non-invasive assessments of vascular function and morphology that are commonly used in medical research to assess different stages of atherosclerosis.

The endothelium is the innermost lining of the vasculature and is involved in the maintenance of vascular homeostasis.  Damage to the endothelium may ...

Early Detection of Drug-Induced Renal Hemodynamic Dysfunction Using Sonographic Technology in Rats

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is estimated to contribute to 19- 25% of all clinical cases of acute kidney injury (AKI) in critically ill patients. AKI detection has historically relied on metrics such as serum creatinine (sCr) or blood urea nitrogen (BUN) which are demonstrably inadequate in full assessment of nephrotoxicity in the early phase of renal dysfunction. Currently, there is no robust diagnostic method to accurately detect hemodynamic alteration in the early phase of AKI while such alterations might actually precede the rise in serum biomarker levels. Such early detection can help clinicians make an accurate diagnosis and help in in decision making for therapeutic strategy. Rats were treated with Cisplatin to induce AKI. Nephrotoxicity was assessed for six days using high-frequency sonography, sCr measurement and upon histopathology of kidney. Hemodynamic evaluation using 2D and Color-Doppler images were used to serially study nephrotoxicity in rats, using the sonography. Our data showed successful drug-induced kidney injury in adult rats by histological examination. Color-Doppler based sonographic assessment of AKI indicated that resistive-index (RI) and pulsatile-index (PI) were increased in the treatment group; and peak-systolic velocity (mm/s), end-diastolic velocity (mm/s) and velocity-time integral (VTI, mm) were decreased in renal arteries in the same group. Importantly, these hemodynamic changes evaluated by sonography preceded the rise of sCr levels. Sonography-based indices such as RI or PI can thus be useful predictive markers of declining renal function in rodents. From our sonography-based observations in the kidneys of rats that underwent AKI, we showed that these noninvasive hemodynamic measurements may consider as an accurate, sensitive and robust method in detecting early stage kidney dysfunction. This study also underscores the importance of ethical issues associated with animal use in research.

Early stage hemodynamic dysfunction is critical to the development of kidney disease. Yet, detection methodologies are limited. Recent advances in sonography provide a noninvasive, accurate option for early detection of kidney injury. This study outlines a step-by-step, sonographic methodology for detecting kidney dysfunction using a drug-induced nephrotoxicity rat model.

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is ...

Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can improve strength in individuals with MS, however; it remains unclear the duration of RST that is needed to make strength gains and how to adapt hip strengthening exercises for individuals of varying strength using only resistance bands. This paper describes the methodology to set up and implement an adapted resistance strength training program, using resistance bands, for individuals with MS. Directions for pre- and post-strength tests to evaluate efficacy of the strength-training program are included. Safety features and detailed instructions outline the weekly program content and progression. Current evidence is presented showing that significant strength gains can be made within 8 weeks of starting a RST program. Evidence is also presented showing that resistance strength training can be successfully adapted for individuals with MS of varying strength with little equipment.

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis. Isolated muscle strengthening is a useful method to target specific weaknesses. This protocol describes a progressive resistance-training program using exercise bands to increase hip muscle strength.

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can ...

Using Saccadometry with Deep Brain Stimulation to Study Normal and Pathological Brain Function

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including Parkinson's and Huntington's can disrupt it. People with Parkinson's disease, for example, tend to have increased saccadic latencies. Consequently, the quantitative measurement of saccadic eye movements has received considerable attention as a potential biomarker for neurodegenerative conditions. A lot more can be learned about the brain in both health and disease by observing what happens to eye movements when the function of specific brain areas is perturbed. Deep brain stimulation is a surgical intervention used for the management of a range of neurological conditions including Parkinson's disease, in which stimulating electrodes are placed in specific brain areas including several sites in the basal ganglia. Eye movement measurements can then be made with the stimulator systems both off and on and the results compared. With suitable experimental design, this approach can be used to study the pathophysiology of the disease being treated, the mechanism by which DBS exerts it beneficial effects, and even aspects of normal neurophysiology.

This paper describes the use of quantitative measurement of eye movements in conjunction with stimulation of focal areas of the deep brain in order to study physiology, pathophysiology, and the mechanisms of deep brain stimulation.

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including ...

Nerve-sparing Mid-urethral Obstruction (NeMO) in Female Small Rodents

Partial bladder outlet obstruction (pBOO) has a high prevalence, causes significant patient burden, and immense health care costs. The most common animal model to investigate bladder remodeling in pBOO are female rodents undergoing partial obstruction at the proximal urethra. Variability in the degree of obstruction and animal mortality are major concerns with proximal obstruction. Furthermore, dissecting around the proximal urethra and bladder neck jeopardizes bladder innervation.
We developed a nerve-sparing mid-urethral obstruction (NeMO) model for pBOO avoiding the disadvantages of the traditional model. We approached the urethra just inferior to the pubic symphysis, which obviated the need for laparotomy as well as for dissection in this area; also, the striated urethral sphincter remained untouched. We performed NeMO in female Sprague-Dawley rats (12 obstructions, 6 sham animals) as well as in female C57/bl6 mice (20 obstructions, 18 sham animals). After two weeks, we evaluated bladder function, bladder mass, and body mass.
We had no mortalities among obstructed- or sham-operated female rats; as described for the traditional proximal pBOO-method, we tied the suture around the proximal urethra and a temporarily placed 0.9 mm metal rod. NeMO induced an 85% increase in bladder mass after two weeks, average residual urine volume was 0.4 mL in partially obstructed rats while only 0.03 mL in sham animals. In mice, we tested 3 sizes of cannulas that we placed along the urethra when tying the suture. We found that using a 27-gauge cannula resulted in over 50% animal mortality; placing the 25-gauge cannula did not yield the desired response in increasing bladder mass; utilizing a 26-gauge cannula yielded favorable results with minimal animal mortality (1/8) yet a significant 2-fold increase in bladder mass.

Nerve-sparing Mid-urethral Obstruction NeMO in Female Small Rodents

Traditional modeling of partial bladder outlet obstruction in rodents is fraught with animal mortality. A denervation injury from dissection around the proximal urethra and bladder neck is also of major concern. We developed and evaluated a safe and reliable mid-urethral obstruction model, avoiding the shortcomings of the traditional model.

Partial bladder outlet obstruction (pBOO) has a high prevalence, causes significant patient burden, and immense health care costs. The most common animal ...

A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible

Valid comparisons of postoperative accuracy results in computer-assisted reconstruction of the mandible are difficult due to heterogeneity in imaging modalities, mandibular defect classification, and evaluation methodologies between studies. This guideline uses a step-by-step approach guiding the process of imaging, classification of mandibular defects and volume assessment of three-dimensional (3D) models, after which a legitimized quantitative accuracy evaluation method can be performed between the postoperative clinical situation and the preoperative virtual plan. The condyles and the vertical and horizontal corners of the mandible are used as bony landmarks to define virtual lines in the computer-assisted surgery (CAS) software. Between these lines the axial, coronal, and both sagittal mandibular angles are calculated on both pre- and postoperative 3D models of the (neo)mandible and subsequently the deviations are calculated. By superimposing the postoperative 3D model to the preoperative virtually planned 3D model, which is fixed to the XYZ axis, the deviation between pre- and postoperative virtually planned dental implant positions can be calculated. This protocol continues and specifies an earlier publication of this evaluation guideline.

Here, we propose a practical, feasible and reproducible evaluation guideline for computer-assisted reconstruction of the mandible in order to create uniformity between studies regarding postoperative accuracy evaluation. This protocol continues and specifies an earlier publication of this evaluation guideline.

Valid comparisons of postoperative accuracy results in computer-assisted reconstruction of the mandible are difficult due to heterogeneity in imaging ...

A Non-Invasive Method for Generating the Cyclic Loading-Induced Intra-Articular Cartilage Lesion Model of the Rat Knee

The pathophysiology of primary osteoarthritis (OA) remains unclear. However, a specific subclassification of OA in relatively younger age groups is likely correlated with a history of articular cartilage damage and ligament avulsion. Surgical animal models of OA of the knee play an important role in understanding the onset and progression of post-traumatic OA and aid in the development of novel therapies for this disease. However, non-surgical models have been recently considered to avoid traumatic inflammation that could affect the evaluation of the intervention. 
In this study, an intra-articular cartilage lesion rat model induced by in vivo cyclic compressive loading was developed, which allowed researchers to (1) determine the optimal magnitude, speed, and duration of load that could cause focal cartilage damage; (2) assess post-traumatic spatiotemporal pathological changes in chondrocyte vitality; and (3) evaluate the histological expression of destructive or protective molecules that are involved in the adaptation and repair mechanisms against joint compressive loads. This report describes the experimental protocol for this novel cartilage lesion in a rat model.

Here, we present the cyclic loading-induced intra-articular cartilage lesion model of the rat knee, generated by 60 cyclic compressions over 20 N, resulting in damage to the femoral condylar cartilage in rats.

The pathophysiology of primary osteoarthritis (OA) remains unclear. However, a specific subclassification of OA in relatively younger age groups is likely ...

Vessel-Sparing Microsurgical Longitudinal Intussusception Vasoepididymostomy to Treat Epididymal Obstructive Azoospermia

The epididymis is a common site of obstruction in obstructive azoospermia (OA). Vasoepididymostomy has become an important method for the treatment of epididymal OA since 2000. There are two challenges in classic microscopic vasoepididymostomy. First, anastomosis of the vas deferens and epididymis is performed with double-needle sutures. However, there is a lack of good-quality and cost-effective double-needle sutures in China, which leads to increased difficulty and poor success rates of anastomosis. Second, the separation of the vas deferens does not retain vasculature, although the vas deferens vasculature plays an important role in the blood supply to the vas deferens, epididymis, and testis. This affects the blood supply to the anastomotic area and epididymis.
Therefore, this team has made innovative improvements to address these problems. Good-quality, cost-effective, single-needle sutures, which are easy to purchase in China and other countries, were used in microsurgical longitudinal intussusception vasoepididymostomy. This can optimize the operation procedure and shorten the operation time while ensuring the success rate of the anastomosis. The surgical method of preserving the vas deferens vessels was innovatively proposed because the etiology of epididymal OA is mostly inflammatory in China. The protection of the blood supply to the vas deferens and epididymis is maximized using microsurgical forceps to separate and protect the vasculature. Patency reached 81.7% in the postoperative follow-up, indicating a better surgical treatment effect.

The present protocol describes a vessel-sparing, longitudinal intussusception vasoepididymostomy using readily available single-needle sutures in China, a safe and effective procedure, which may improve patients' patency and natural pregnancy rates.

The epididymis is a common site of obstruction in obstructive azoospermia (OA). Vasoepididymostomy has become an important method for the treatment of ...

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Vessel-Sparing Microsurgical Longitudinal Intussusception Vasoepididymostomy to Treat Epididymal Obstructive Azoospermia