Unembalmed Cadavers Research Articles

The Peridural Membrane of the Lumbar Spine Has Characteristics of Synovium

Recent investigations have renewed interest in a thin well‐innervated peridural membrane PDM which envelopes the contents of the spinal canal and neural foramen in human. Anatomical relations of the PDM in the neural foramen suggest that the suprapedicular compartment of the neural foramen functions as a joint cavity with PDM as its boundary. Inflamed and sensitized PDM may be a source of common low back pain. The purpose of this investigation is to evaluate PDM in the caudal compartment of the neural foramen of the lumbar spine for histological and immunohistochemical (IHC) characteristics of synovium.Dorsolateral and suprapedicular samples of PDM in the lumbar spine of an unembalmed human cadaver were obtained. Samples were evaluated using hematoxylin and eosin staining (HE) and IHC. Four slices of each sample were analyzed (FDNeurotech). Monoclonal and polyclonal antibodies to CD44 (hyaluronan receptor), CD55 (fibroblast like synoviocyte), CD68 (macrophage like synoviocyte) and HAS2 (hyaluronan synthetase 2) were used. Results were evaluated using A1 Nikon confocal immunofluorescent microscopy.HE staining showed a continuous membrane that contains extensive vascular and lymphatic plexus and duct‐like structures, dense and loose fibrous tissue, adipose tissue and nerve tissue in all samples. CD44 was expressed extensively throughout tissues of PDM in all samples, predominantly in perivascular areas but also in adipose, fibrous and nerve tissue. Numerous CD55 positive cells in layer like formations between and around vessels and in the wall of duct‐like structures and in the outer layers of PDM were seen in all samples. CD68 positive cells were found in all samples, but were sparse and mainly found in the outer layer of the membrane. HAS2 positive cells in layer like distributions between vessels or deep to the outer layer of the membrane were found extensively in all samples. Distributions of CD55 and HAS@ positive columnar cells in walls of duct‐like structures and blood vessels were observed in several samples.The results of this study indicate that PDM has histological and IHC characteristics of synovium. IHC identification of CD68 positive cells in the outer layers of PDM and CD55 throughout the membrane, in conjunction with conventional microscopic evaluation of the membrane, suggests the presence of an intima and subintima in PDM similar to synovium. Indeed, PDM histology similar to synovium has been reported by the author and presence of CD44, CD55, CD68 and HAS2 in synovium has been shown by other investigators. No prior reports on the presence of these markers in PDM are available in the literature. Extensive distribution of HAS2 and CD44 in PDM suggests that PDM plays a role in lubrication and homeostasis of the neural foramen and epidural cavity. Presence of CD68, a marker for macrophages, CD55, a receptor involved in regulation of complement activation and CD44, a receptor for metalloproteinases and other inflammatory mediators, indicates that PDM plays an important role in the inflammatory response to tissue injury and pain originating from the spine.Support or Funding InformationTexas Tech University Endowed professorshipThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Anatomic and Radiologic Study of Renal Avascular Plane (Brödel's Line) and Its Potential Relevance on Percutaneous and Surgical Approaches to the Kidney.

The aim of the present anatomic and radiologic study was to evaluate the location, extension, and characteristics of the Brödel's plane and eventually define its different patterns. We evaluated 15 human normal kidneys sampled from unembalmed cadavers without clinical history or anatomical evidence of renal diseases. Kidneys with the surrounding perirenal fat tissue were removed en bloc with the abdominal segment of the aorta. The renal artery was injected with acrylic and radiopaque resins. A CT examination of the injected kidneys was performed. After the imaging acquisition, the specimens were treated with sodium hydroxide for removal of the parenchyma to obtain the vascular casts. All the CT images were elaborated using dedicated three-dimensional (3D) software with the aim to improve the possibility to identify the Brödel's plane. The avascular plane was identified directly on the vascular casts and confirmed on the corresponding 3D images. The avascular plane was located in all cases medially to the lateral convex border of the kidneys. The recorded mean distance was 2.04 cm (range 1.8-2.4 cm). Three patterns of distribution of the Brödel's line were identified. In five (33.3%) cases the avascular plane was extended from the apical to the inferior segment of the kidneys (type 1); in six (40%) from the superior to the inferior segment (type 2); and in four (26.7%) from the apical to the middle segment (type 3). Fourth and fifth order vessels crossing the Brödel's line were detected in all the analyzed cases. The renal avascular plane showed a different extension allowing us to cluster three different patterns. Preoperative identification of the Brödel's line patterns could help surgeons to minimize hemorrhagic complications during percutaneous and surgical procedures requiring an incision of the renal parenchyma such as traditional or robot-assisted nephrolithotomy or partial nephrectomy for endophytic renal tumors. Radiologic studies validated that the described patterns in the clinical practice are strongly needed.

Ultrasound-Guided Posterior Femoral Cutaneous Nerve Block: A Cadaveric Study.

To identify any anatomic barriers to local anesthetic spread between the sciatic nerve (SN) and the posterior femoral cutaneous nerve (PFCN) at the level of the infragluteal crease and to describe a potential technique for an ultrasound (US)-guided subgluteal PFCN block in a cadaveric model. Bilateral US-guided subgluteal injections of a colored latex solution were performed around the SN (15 mL) and PFCN (10 mL) in 4 unembalmed cadavers, for a total of 8 cadaver thighs. The specimens were dissected after latex polymerization to observe the spread of the latex solutions. With US guidance, the PFCN was visualized deep to the gluteus maximus and slightly superficial or lateral to the SN at the level of the infragluteal crease. The SN and PFCN were found on dissection to be coated with their respective colored latex in all 8 thighs. The SN and PFCN were consistently separated by the deep investing muscular fascia of the thigh, with only 2 thighs showing substantial mixing of latex injectates. The deep investing muscular fascia of the thigh appears to impede the spread of injectate between the SN and PFCN in a most unembalmed cadaver specimens. A US-guided subgluteal PFCN blockade may be a feasible technique to complement an SN block when complete anesthesia of the posterior thigh is required.

The mid‐point transverse process to pleura (MTP) block: a new end‐point for thoracic paravertebral block

Current descriptions of thoracic paravertebral block techniques require the needle tip to be anterior to the superior costotransverse ligament. We hypothesised that an injection point midway between the posterior border of the transverse process and the pleura would result in spread to the paravertebral space. We completed bilateral injections of 5 ml methylene blue 0.2% midway between the posterior border of the transverse process and the pleura at T2, T4, T6, T8 and T10 in three unembalmed cadavers. The presence of methylene blue dye at the nerve root in the paravertebral space, the corresponding intercostal nerve and sympathetic chain at the level of injection, and at additional levels, was examined. We identified the superior costotransverse ligament, pleural displacement and spread to the erector spinae plane. We describe two case reports using this technique in patients. Our cadaver results and clinical cases demonstrate that, with the exception of cadaver 1, an injection point midway between the posterior border of the transverse process and pleura consistently achieved spread of dye at least to the paravertebral space at the level of injection, and frequently to adjacent levels. This may be a plausible explanation for the landmark technique's inability to reliably achieve a multilevel block. We describe a new ultrasound-guided technique for a single level paravertebral block.

Effect of neurodynamic mobilization on fluid dispersion in median nerve at the level of the carpal tunnel: A cadaveric study

ObjectivesTo evaluate the effect of neurodynamics mobilization (NDM) on an artificially induced edema in the median nerve at the level of the carpal tunnel in unembalmed cadavers and to assess whether NDM tensioning techniques (TT) and NDM sliding techniques (SLT) induce similar effects on intraneural fluid dispersion. DesignFourteen upper extremities of seven unembalmed cadavers were used in this study. A biomimetic solution was injected directly under the epineurium of the median nerve at the level of the proximal transverse carpal ligament. The initial dye spread was allowed to stabilize and measured with a digital caliper. Tensioning and sliding techniques were applied following a randomized crossover design to each upper extremity and were performed for a total of 5 min each. Post-intervention dye spread measurements were taken after each technique. ResultsAfter the first mobilization, the mean longitudinal dye spread (7.5 ± 6.6 mm) was significantly greater (p = 0.024) compared to the stabilized dye spread. There was a significant longitudinal diffusion effect with both, TT (p = 0.018) and SLT (p = 0.016), with no statistically significant difference between techniques (p = 0.976). The order in which techniques were administered did not influence the diffusion. ConclusionFive minute of passive NDM in the form of tensioning or sliding technique induced significant fluid dispersion in the median nerve at the carpal tunnel of unembalmed human cadavers. This study provides support for clinical mechanism of NDM in reducing intraneural edema.

Surgical hip dislocation through a direct lateral approach: A cadaveric study of vascular danger zones.

There is limited information on the potential danger to the vascularity of the femoral head during surgical dislocation of the hip using the direct lateral approach. The objective of this study was to investigate the topographical anatomy of the medial femoral circumflex artery (MFCA), the primary source of blood supply to the femoral head, in relationship to the direct lateral approach. Seven unembalmed cadaver hips had dye injection into either the profunda femoris artery or the MFCA. Surgical hip dislocation was then performed through a direct lateral approach, noting the danger zones to the MFCA branches during each step of the exposure. None of the MFCA branches were found to cross the anterior surgical field superficial to the capsule. The deep (main) branch of the MFCA pierced the inferior capsule at the level of the lesser trochanter after emerging posterior to iliopsoas tendon. Ascending branches up the medial femoral neck were identified at this level. The deep branch then coursed posteriorly terminating in a variable number of vessels ascending the posterior femoral neck. Dislocation of the femoral head did not stretch or alter the course of the deep branch of the MFCA. Safe surgical hip dislocation preserving the MFCA can be performed though a direct lateral approach as long as the inferomedial portion of the anterior capsule is preserved (main branch of the MFCA pierces the capsule at this level). Extracapsular injury is possible from inadvertent dissection at the level of the lesser trochanter or aggressive retraction on the iliopsoas. The posterior capsule should be left intact and instrumentation around the posterior neck should be avoided.

Anatomo-radiological patterns of pancreatic vascularization, with surgical implications: Clinical and anatomical study.

The pancreas receives multiple arterial sources that should be considered in patients undergoing pancreatic surgery. The aim of this study is to describe pancreatic vascularization and to explore the anatomical basis of postoperative complications. Ten specimens from unembalmed cadavers, including the retroperitoneal vessels and organs and spleen, were injected with acrylic resins to obtain vascular casts. Thirty computed tomography angiographies (CTA) of subjects with no pancreatic pathology (mean age 70.9 years) were also analyzed. A paucivascular area at the neck of the pancreas was apparent in all vascular casts. At CTA: (1) the transverse pancreatic artery, the only artery running from the cervicocephalic to the somatocaudal segment, was visible in 76.9% of cases; (2) the splenic artery was suprapancreatic in 66.7% and intrapancreatic with a tortuous course in 33.3%; (3) the posterior superior pancreaticoduodenal artery was visible in 100% of cases, the anterior superior pancreatico-duodenal artery in 92.6%, the anterior inferior pancreaticoduodenal artery in 73.1%, the posterior inferior pancreaticoduodenal artery in 86.4%, the dorsal pancreatic artery in 65.4%, the great pancreatic artery in 73.1%, and the pancreatic arteries to the body and caudal pancreatic arteries in 96.2%. Our study demonstrated great individual variability of the pancreatic vasculature, which can be explored by CTA and could be relevant to surgical procedures. Clin. Anat. 30:614-624, 2017. © 2017 Wiley Periodicals, Inc.

The effects of hip abduction on sciatic nerve biomechanics during terminal hip flexion.

Terminal hip flexion contributes to increased strain in peripheral nerves at the level of the hip joint. The effects of hip abduction and femoral version on sciatic nerve biomechanics are not well understood. A decrease in sciatic nerve strain will be observed during terminal hip flexion and hip abduction, independent of femoral version. Six un-embalmed human cadavers were utilized. Three Differential Variable Reluctance Transducers (DVRTs) sensors were placed on the sciatic nerve while the leg was flexed to 70° with a combination of − 10°, 0°, 20° and 40° adduction/abduction. DVRT placement included: (i) under piriformis, (ii) immediately distal to the gemelli/obturator, (iii) four centimeters distal to sensor two. A de-rotational osteotomy to decrease femoral version 10° was performed, and sciatic nerve strain was measured by the same procedure. Data were analyzed with three-way analysis of variance and Bonferroni post-hoc analysis to identify differences in the mean values of sciatic nerve strain between native and decreased version state, hip abduction angle and DVRT sensor location. Significant main effects were observed for femoral version (P = 0.04) and DVRT sensor location (P = 0.01). Sciatic nerve strain decreased during terminal hip flexion and abduction in the decreased version state. An 84.23% decrease in sciatic nerve strain was observed during hip abduction from neutral to 40° in the presence of decreased version at terminal hip flexion. The results obtained from this study confirm the role of decreased femoral version and hip abduction at terminal hip flexion to decrease the strain in the sciatic nerve.

Perforating and deep lymphatic vessels in the knee region: an anatomical study and clinical implications.

To determine the relationship between the perforating and deep lymphatic vessels in the knee region for clinical implications. Four lower limbs from two unembalmed human cadavers were used. Under a surgical microscope, 6% hydrogen peroxide was employed to detect lymph vessels accompanying the small saphenous vein, anterior tibial, posterior tibial and fibular blood vessels all commencing from distal ends of specimens. Each lymphatic vessel was inserted by a 30-gauge needle and injected with a barium sulphate mixture. Each specimen was dissected, radiographed and photographed to determine the perforating and deep lymphatic vessels in the region. A perforating lymph vessel was observed in the popliteal fossa of each specimen. It arose from the superficial popliteal lymph node and terminated in the deep popliteal lymph node. The anterior tibial, posterior tibial and peroneal lymph vessels were discovered in the region travelling with the corresponding vascular bundles. After penetrating the vascular aperture of the interosseous membrane between the tibia and fibula, the anterior tibial lymph vessel entered directly into the deep popliteal lymph node or converged to either the posterior tibial or fibular lymph vessel, before entering the node. The posterior tibial and peroneal lymph vessels entered the deep popliteal lymph node. The efferent lymph vessel of the deep popliteal lymph node travelled with the femoral vascular bundle. The perforating and deep lymphatic vessels in the knee region has been presented and discussed. The information advances our anatomical knowledge and the results will benefit clinical management.

Anatomical Relationships of Burch Colposuspension Sutures.

The prevalent use of minimally invasive midurethral slings for the treatment of stress urinary incontinence in the last several decades has resulted in fewer Burch procedures being performed and diminished surgical experience in performing the Burch colposuspension. However, recent antimesh media has resulted in more patients requesting nonmesh anti-incontinence procedures and a subsequent need for surgeons to refamiliarize themselves with the Burch procedure and its relevant anatomy. The objective of this study was to evaluate the relationships of Burch sutures to surrounding neurovascular anatomic structures in the human cadaver. The retropubic space of 11 unembalmed female cadavers was dissected, and a Burch procedure performed. The distance from the Burch sutures' location through both Cooper's ligament and the vagina to the obturator neurovascular bundle and external iliac vessels was measured. The mean distance from the most lateral stitch in Cooper's ligament to the obturator bundle was 25.9 ± 7.6 mm and to the external iliac vessels was 28.9 ± 9.3 mm, and in some instances, these structures were less than 1.5 cm away. The obturator bundle and external iliac lie, on average, within 3 cm of sutures placed during a Burch colposuspension. Knowledge of these anatomical relationships is valuable when dissecting the space of Retzius and placing sutures for a Burch to avoid injury.

Anatomical study of renal arterial vasculature and its potential impact on partial nephrectomy.

To validate Graves' classification of the intrarenal arteries and to verify the absence of collateral arterial blood supply between different renal segments, in order to maximize peri-operative and functional outcomes of partial nephrectomy. The study was performed on 15 normal kidneys sampled from eight unembalmed cadavers. Kidneys with the surrounding perirenal fat tissue were removed en bloc with the abdominal segment of the aorta. The renal artery was injected with acrylic and radiopaque resins, with the specimen suspended in water. CT examination of the injected kidneys was performed to analyse the branches located deeply. After imaging acquisition, the specimens were treated with sodium hydroxide for removal of the parenchyma to obtain vascular casts. Ten casts (66.6%) showed the classic subdivision of the main artery into single posterior and anterior branches. With regard to the distribution of the segmental or second-order arteries, only two casts (13%) showed a pattern similar to that described by Graves, characterized by four segmental (second-order) branches coming from the anterior renal artery (apical, superior, middle and inferior). In the remaining 13 kidneys (87%) a different arterial vascular network was detected. In 10 casts (80%) a single renal segment was vascularized by two or more different branches coming from an artery leading to another segment (multiple vascularization). Multiple vascularization was observed in three (20%) apical segments, five (33%) superior segments, six (40%) middle segments, seven (47%) inferior segments and two (13%) posterior segments. This study shows that in the human kidneys the arterial vasculature is frequently different from that described by Graves. Moreover, in a significant percentage of cases, a single renal segment receives two or more branches that originate from an artery leading to another segment.

Intra-pelvic pressure changes after pelvic fracture: A cadaveric study quantifying the effect of a pelvic binder and limb bandaging over a bolster

IntroductionUnstable pelvic fractures can be life-threatening due to catastrophic haemorrhage. Non-invasive methods of reducing and stabilising these injuries include pelvic binder application and also lower limb bandaging over a knee-flexion bolster. Both of these methods help close the pelvic ring and should tamponade bleeding. This study aimed to quantify the intra-pelvic pressure changes that occurred with 3 different manoeuvres: lower limb bandaging over a bolster; a Trauma Pelvic Orthotic Device (T-POD) pelvic binder, and a combination of both. MethodsFollowing a pilot study with 2 soft embalmed cadavers, a formal study with 6 unembalmed cadavers was performed. For each specimen an unstable pelvic injury was created (OA/OTA 61-C1) by dividing the pelvic ring anteriorly and posteriorly. A 3–4cm manometric water-filled balloon was placed in the retropubic space and connected to a 50ml syringe and water manometer via a 3-way tap. A baseline pressure of 8cmH2O (equating to the average central venous pressure) was used for each cadaver. Steady intra-pelvic pressures (more reliably reflecting the pressures achieved following an intervention) were used in the subsequent statistical analysis, using R statistical language and Rstudio. Paired t-test or Wilcoxon’s rank sum test were used (depending on the normality of the dataset) to determine the impact of each intervention on the intra-pelvic pressure. ResultsThe mean steady intra-pelvic pressures were significantly greater than the baseline pressure for each intervention. The binder and limb bandaging over a bolster alone increased the mean steady pelvic pressures significantly to 24 (SE=5) (p<0.036) and 15.5 (SE=2) (p<0.02)cmH2O respectively. Combining these interventions further increased the mean steady pressure to 31 (SE=7)cmH2O. However, this was not significantly greater than pressures for each of the individual interventions. DiscussionBoth lower limb bandaging over a bolster and pelvic binder application significantly increased intra-pelvic pressure above the baseline pressure. This was further increased through combining these interventions, which could be useful clinically to augment haemorrhage control in these fractures. ConclusionLower-limb bandaging over a bolster, and pelvic binder application, both significantly increased intra-pelvic pressures, and were greatest in combination. These findings support the use of these techniques to facilitate non-surgical haemorrhage control.

Cadaveric Study of the Articular Branches of the Shoulder Joint.

This cadaveric study investigated the anatomic relationships of the articular branches of the suprascapular (SN), axillary (AN), and lateral pectoral nerves (LPN), which are potential targets for shoulder analgesia. Sixteen embalmed cadavers and 1 unembalmed cadaver, including 33 shoulders total, were dissected. Following dissections, fluoroscopic images were taken to propose an anatomical landmark to be used in shoulder articular branch blockade. Thirty-three shoulders from 17 total cadavers were studied. In a series of 16 shoulders, 16 (100%) of 16 had an intact SN branch innervating the posterior head of the humerus and shoulder capsule. Suprascapular sensory branches coursed laterally from the spinoglenoid notch then toward the glenohumeral joint capsule posteriorly. Axillary nerve articular branches innervated the posterolateral head of the humerus and shoulder capsule in the same 16 (100%) of 16 shoulders. The AN gave branches ascending circumferentially from the quadrangular space to the posterolateral humerus, deep to the deltoid, and inserting at the inferior portion of the posterior joint capsule. In 4 previously dissected and 17 distinct shoulders, intact LPNs could be identified in 14 (67%) of 21 specimens. Of these, 12 (86%) of 14 had articular branches innervating the anterior shoulder joint, and 14 (100%) of 14 LPN articular branches were adjacent to acromial branches of the thoracoacromial blood vessels over the superior aspect of the coracoid process. Articular branches from the SN, AN, and LPN were identified. Articular branches of the SN and AN insert into the capsule overlying the glenohumeral joint posteriorly. Articular branches of the LPN exist and innervate a portion of the anterior shoulder joint.

Vascular anatomical relationships of the retropubic space and the sacrospinous ligament, using three-dimensional imaging

Pelvic anatomy is complex and intimate knowledge of variabilities in anatomical relationships is critical for surgeons to safely perform surgical procedures. Three-dimensional Imaging provides the opportunity to analyze undisturbed anatomical relationships. The authors hypothesized that three-dimensional models created from pelvic computed tomography angiograms could be used to obtain vascular anatomical measurements, and that the measurements obtained from three-dimensional models would be similar to those from cadaver studies. We included all pelvic computed tomography angiograms that were acquired in female patients older than 18years at our institution within the previous 5years. Three-dimensional models were created using the Invivo5 software based on the Digital Imaging and Communications in Medicine files. Structures of interest were virtually dissected and measured replicating previous cadaver studies. Statistical analysis of demographics and measurements was performed. The final analysis included 87 studies. The average age of the subjects was 66.9years and their average BMI was 26.1kg/m2. Of the 87 subjects, 12.6% had a history of hysterectomy, 2.3% a history of a continence procedure, and 1.1% a history of a prolapse procedure. The range of distance between the ischial spine and the pudendal artery was 3-17mm. The closest vessels to the lower edge of the symphysis pubis were the obturator vessels. The aberrant corona mortis vessel was present in 27.9% of the subjects. Prior hysterectomy was associated with changes in the measurements of the obturator arteries with minimal changes in other measurements. Our results indicate that this technology provides similar measurements to those found in previous unembalmed cadaver studies. This technology offers a great opportunity to study anatomical relationships in a native undisturbed state.

Sciatic Nerve Intercommunications: New Finding

Communicating branches between the tibial and common fibular divisions of the sciatic nerve have not been previously described. The aim of our study was to examine such neural connections. Twenty unembalmed adult cadavers underwent dissection of the sciatic nerve. Observations were made for interneural communications between the tibial and common fibular divisions of this nerve. When present, these were measured and classified. The majority of sides (75%) had neural communications between the parts of the sciatic nerve in the gluteal/posterior thigh regions before the normal bifurcation of the nerve just above the knee. These connections were always within 20 cm of the greater sciatic notch. Most connections were represented by Testut intercommunicating branches types A (14 sides), F (8 sides), and D (2 sides). Most sides were found to have 1 location for sciatic nerve intercommunications. However, 4 sides (13%) had multiple locations (up to 3) for these intercommunications. The mean length of the communications was 4.1 cm, and the mean diameter was 2.4 mm. No statistically significant difference was found between sides or sexes. To our knowledge, neural interconnections between the divisions of the sciatic nerve in the posterior thigh have not been described in the extant literature. Such data might help explain unusual neurologic examinations and alert the surgeon as to the potential for encountering such connections at operation.

Randomized comparison of popliteal-sciatic perineural catheter tip migration and dislocation in a cadaver model using two catheter designs.

BackgroundNew catheter-over-needle (CON) technology for continuous peripheral nerve blockade has emerged, but its effect on the risk of perineural catheter tip dislocation is unknown. Less flexible catheters may be more likely to migrate away from the nerve with simulated patient movement. In the present study, we evaluated catheter tip migration between CON catheters and traditional catheter-through-needle (CTN) catheters during ultrasound-guided short-axis in-plane (SAX-IP) insertion.MethodsWe evaluated the migration of popliteal-sciatic catheters in a prone, unembalmed male cadaver. Thirty catheter placement trials were divided randomly into two groups based on the catheter type: CON or CTN. A single anesthesiology resident placed the catheters by SAX-IP insertion, and the catheters were then examined by ultrasound before and after ipsilateral knee range of motion (ROM) exercises (0°–130° flexion). A blinded expert regional anesthesiologist performed caliper measurements on the ultrasound images before and after the ROM exercises. The primary outcome was the change in distance from the catheter tip to the center of the nerve (cm) between before and after the ROM exercises.ResultsThe change in the tip-to-nerve distance (median [10th–90th percentile]) was 0.06 (−0.16 to 0.23) cm for the CTN catheter and 0.00 (−0.12 to 0.69) for the CON catheter (P = 0.663). However, there was a statistically significant increase in dislocation out of the nerve compartment for the CON catheter (4/15; 0/15 for CTN) (P = 0.043).ConclusionsAlthough the use of different catheter designs had no effect on the change in the measured migration distance of popliteal-sciatic catheters, 27% of the CON catheters were dislocated out of the nerve compartment. These results may influence the choice of catheter design when using SAX-IP perineural catheter insertion.

The dorsal nerve of the clitoris in relation to urinary incontinence sling procedures.

To avoid injury to the perineal branches of the pudendal nerve during urinary incontinence sling procedures, a thorough knowledge of the course of these nerve branches is essential. The dorsal nerve of the clitoris (DNC) may be at risk when performing the retropubic (tension-free vaginal tape) procedure as well as the inside-out and outside-in transobturator tape procedures. The purpose of this study was to identify the anatomical relationships of the DNC to the tapes placed during the procedures mentioned and to determine the influence of body variations. In this cadaveric study, the body mass index (cBMI) of unembalmed cadavers was determined. Suburethral tape procedures were performed by a registered urologist and gynecologist on a sample of 15 female cadavers; six retropubic, seven inside-out and nine outside-in transobturator tapes were inserted. After embalmment, dissections were performed and the distances between the DNC and the tapes measured. In general the trajectory of the outside-in tape was closer to the DNC than that of the other tapes. cBMI was weakly and nonsignificantly correlated with the distance between the trajectory of the tape and the DNC for the inside-out tape and the tension-free vaginal tape, but not for the outside-in tape. The findings suggest that the DNC is less likely to be injured during the inside-out tape procedure than during the outside-in procedure, regardless of BMI. Future studies on larger samples are desirable to confirm these findings.

A Cadaveric Study for the Improvement of Thread Carpal Tunnel Release

The thread carpal tunnel release (TCTR) technique has been improved and offers more precise control in dissecting thread placement. The purpose of this cadaveric study was to test the procedure operationally and verify the modified TCTR anatomically. Eleven unembalmed cadaver wrists underwent the transverse carpal ligament (TCL) release by using the modified TCTR technique. An experienced observer dissected each specimen and assessed for completeness of release under direct visual assessment. Injury to the superficial palmar aponeurosis (SupPA), the Berrettini and common digital nerve branches were also recorded as a secondary outcome. Eleven out of 11 wrists (100%) underwent the modified TCTR with complete release of the TCL. All 11 wrists were released without damage to any vital neurovascular structure including the Berrettini branch and the common digital nerves. The SupPA remained intact in all 5 wrists performed with the preservation steps. The modified TCTR technique demonstrated complete division of the TCL while protecting the SupPA as well as the Berrettini and common digital nerve branches. The modified TCTR has the potential to offer a clinically safe and effective minimally invasive procedure for complete carpal tunnel release.

Comparison of Ventilation With One-Handed Mask Seal With an Intraoral Mask Versus Conventional Cuffed Face Mask in a Cadaver Model: A Randomized Crossover Trial

We compare received minute volume with an intraoral mask versus conventional cuffed face mask among medics obtaining a 1-handed mask seal on a cadaver model. This study comprised a randomized crossover trial of adult US Army combat medic volunteers participating in a cadaver laboratory as part of their training. We randomized participants to obtain a 1-handed mask seal during ventilation of a fresh unembalmed cadaver, first using either an intraoral airway device or conventional cuffed face mask. Participants obtained a 1-handed mask seal while a ventilator delivered 10 standardized 750-mL breaths during 1 minute. After a 5-minute rest period, they repeated the study with the alternative mask. The primary outcome measure was received minute volume as measured by a respirometer. Of 27 recruited participants, all completed the study. Median received minute volume was higher with the intraoral mask compared with conventional cuffed mask by 1.7 L (95% confidence interval 1.0 to 1.9 L; P<.001). The intraoral mask resulted in greater received minute volume received compared with conventional cuffed face mask during ventilation with a 1-handed mask seal in a cadaver model. The intraoral mask may prove a useful airway adjunct for ventilation.

Proximity of uterosacral ligament suspension sutures and S3 sacral nerve to pelvic landmarks.

To describe the relationships between pelvic bony landmarks to points along the third sacral nerve and to uterosacral ligament suspension sutures. Three transvaginal uterosacral ligament suspension sutures were placed bilaterally in unembalmed female human cadavers. The third sacral nerve was marked at the foramen (S3a) and at two additional points at 1-cm intervals along its course caudally (S3b, S3c). Three bony pelvic landmarks were identified and marked, including the ischial spine, pubic symphysis, and coccyx. Distances from each landmark to each suture and nerve point were measured. The distance from each landmark to each S3 nerve point was extended radially, encompassing an arbitrary zone in which sutures may be placed and thus where nerve injury may occur. Zones of potential nerve injury included: zone A (closest to the sacral nerve root), zone B, and zone C (closest to the landmark). Descriptive statistics were used and comparisons were made using Student's t test and ANOVA. Ten cadaver specimens were dissected. For the ischial spine, the distances to points S3a, S3b, and S3c were 6.3, 5.4, and 4.6cm respectively. Approximately two thirds of the sutures were noted beyond zone C, indicating a potentially increased risk of nerve injury with suture placement in zones farthest from the ischial spine given their proximity to the sacral nerve. Using the ischial spine as a landmark, increased sacral nerve injury could result from suture placement beyond the mean distance of 4.6cm from the ischial spine. The use of bony landmarks in avoiding sacral nerve injury may be as important as suture depth and angle of suture placement.