[Total trans-oral endoscopic thyroidectomy and cervical lymphadenectomy: a human cadavers surgery study].

OBJECTIVE: To find an approach for trans-oral endoscopic thyroidectomy (TOET) and cervical lymphadenectomy using conventional endoscopic surgical instruments on frozen fresh cadavers. METHODS: Six frozen fresh cadavers were used in three groups of trans-oral trocar installation experiments: oral vestibule installation, sublingual region installation, and combined bi-vestibular and sublingual installation. TOET (with pretrachealis method to thyroid fixation removal) and cervical lymphadenectomy were performed experiments on another 6 frozen fresh cadavers using the best access approach found in the aforementioned experiments. RESULTS: In oral vestibule trocar installations, the trocars caused large lacerated wound and damaged air tightness. In sublingual installations, only one trocar could be installed in the sublingual area because the space in sublingual area was limited. In combined bi-vestibular and sublingual installations, no gland, vessel or nerve was damaged. Combined bi-vestibular and sublingual access were selected as the surgical approach on the basic of analysis the merits of each approach. TOET and cervical lymphadenectomy in area III, IV, VI, VII were performed without making any accessory damage through combined bi-vestibular and sublingual access approach. CONCLUSIONS: TOET is feasible. Combined bi-vestibular and sublingual approach is available for TOET. Part of the cervical lymph nodes could be resected. Pretrachealis approach to thyroid fixation removal can still be used.

Clinical anatomy and 3D virtual reconstruction of the lumbar plexus with respect to lumbar surgery.

BACKGROUND: Exposure of the anterior or lateral lumbar via the retroperitoneal approach easily causes injuries to the lumbar plexus. Lumbar plexus injuries which occur during anterior or transpsoas lumbar spine exposure and placement of instruments have been reported. This study aims is to provide more anatomical data and surgical landmarks in operations concerning the lumbar plexus in order to prevent lumbar plexus injuries and to increase the possibility of safety in anterior approach lumbar surgery. METHODS: To study the applied anatomy related to the lumbar plexus of fifteen formaldehyde-preserved cadavers, Five sets of Virtual Human (VH) data set were prepared and used in the study. Three-dimensional (3D) computerized reconstructions of the lumbar plexus and their adjacent structures were conducted from the VH female data set. RESULTS: The order of lumbar nerves is regular. From the anterior view, lumbar plexus nerves are arranged from medial at L5 to lateral at L2. From the lateral view, lumbar nerves are arranged from ventral at L2 to dorsal at L5. The angle of each nerve root exiting outward to the corresponding intervertebral foramen increases from L1 to L5. The lumbar plexus nerves are observed to be in close contact with transverse processes (TP). All parts of the lumbar plexus were located by sectional anatomy in the dorsal third of the psoas muscle. Thus, access to the psoas major muscle at the ventral 2/3 region can safely prevent nerve injuries. 3D reconstruction of the lumbar plexus based on VCH data can clearly show the relationships between the lumbar plexus and the blood vessels, vertebral body, kidney, and psoas muscle. CONCLUSION: The psoas muscle can be considered as a surgical landmark since incision at the ventral 2/3 of the region can prevent lumbar plexus injuries for procedures requiring exposure of the lateral anterior of the lumbar. The transverse process can be considered as a landmark and reference in surgical operations by its relative position to the lumbar plexus. 3D reconstructions of the lumbar plexus based on VCH data provide a virtual morphological basis for anterior lumbar surgery.

[Surgical anatomy of totally trans-oral video-assisted thyroidectomy].

OBJECTIVE: To define the anatomical approach, anatomical planes and related vessels and nerves to create a safe and reproducible combined sublingual and bi-vestibular access for trans-oral video-assisted thyroidectomy. METHODS: From November 2009 to May 2011, twenty-five embalmed human specimens were dissected for anatomical information of the cervical region, the mandible region and the supra-hyoid muscles. On twenty fresh frozen human specimens after an experimental trans-oral endoscopic thyroidectomy, the related vascular, neural structures and muscles were evaluated. RESULTS: The optical access port was placed in the midline sublingual. The geniohyoid muscle, mylohyoid muscle and the anterior belly of the digastric muscle were divided in the midline in order to reach the plane under the platysma muscle. The mucosa was sagittal incised bilaterally in the vestibular of oral cavity for working trocar, at the level of the first molar of the mandible. The working trocar reached directly the periosteum of the mandible, under the facial vessel and the marginal branch of facial nerve, and then passed below the platysma muscle into the infra-laryngeal working area. The distance from mental nerve to mandibular midline and between mental nerve and facial artery were (25.8 ± 0.9) mm and (29.4 ± 0.9) mm respectively. Anatomical dissections showed that after an experimental trans-oral combined sublingual and bi-vestibular access, all muscles of the floor of the oral cavity as well as the related vascular and neural structures are intact. The maximum nodule size of the resected specimens in the totally trans-oral approach was up to 50 mm. CONCLUSION: The combined sublingual and bi-vestibular access of trans-oral video-assisted thyroidectomy is safe and reproducible.

Perirectal fascia and spaces: annular distribution pattern around the mesorectum.

PURPOSE: In view of debate on the optimal surgical planes for total mesorectal excision, this study was designed to explore the regional anatomy of the perirectal fascia and spaces. METHODS: Twenty-one cadavers (15 male and 6 female) were embalmed and their vessels visualized by injection with color dye. From the cadavers, 30 hemipelves and 6 three-quarter pelves were harvested. The perirectal fascia and spaces and the pelvic autonomic nerves were dissected and examined. RESULTS: Three tissue layers were dissected from the inside to the periphery: the proper rectal fascia enveloping the mesorectum, the presacral fascia, and the piriformis fascia fused with the sacral periosteum. The mesorectum comprised 2 parts: posterior, with the classical posterolateral fat covered by the proper rectal fascia; and anterior, with the anterior fat covered by the posterior layer of Denonvilliers fascia. Extending anteriorly to the anterior layer of Denonvilliers fascia, the presacral fascia bisected the space between the mesorectum and the piriformis fascia into the retrorectal space and the presacral space. The retrorectal space extended cranially to the left Toldt's space, anterior to the space between the 2 layers of Denonvilliers fascia. CONCLUSIONS: From the inside to the periphery, the proper rectal fascia, the presacral fascia, and the muscular fascia are distributed in an annular pattern around the mesorectum. The presacral fascia divides the perirectal space into 2 annular parts: the central retrorectal space and the peripheral presacral space. The retrorectal space is the ideal surgical plane for the total mesorectal excision.

Clinical anatomy study of autonomic nerve with respective to the anterior approach lumbar surgery.

INTRODUCTION: Male genital dysfunction was recognized as a complication following anterior approach lumbar surgery. Disruption of efferent sympathetic pathways such as the abdominal aortic plexus (AAP) and superior hypogastric plexus (SHP) which lied pre-abdominal aorta and iliac artery had been thought as the main reason. Though there were some clinical reports of retrograde ejaculation, the applied anatomic study of the autonomic nerve anterior to the lumbar was little. The purpose was to find out a lumbar surgery approach which was ejaculation preservation through the detailed study of the anatomy and histology observation of the autonomic nerve anterior to the lumbar vertebrae. METHODS: The lumbar region of ten male cadavers was dissected and analyzed. We investigated the relationship between the peritoneum and abdominal aorta, iliac artery and sacral promontory fascia, as well as the trend and distribution of the autonomic nerve and SHP anterior to the L5-S1. We also observed the distribution of autonomic nerve at retroperitoneum through hematoxylin and eosin (HE)-stained tissues pre-aorta, para-aorta, and pre-vertebrae sacrales. RESULTS: Superior hypogastric plexus, which deviated to left, located in a triangle formed by the common iliac arteries and its bilateral branches, its truck sited anterior to the lumbarsacral space in seven cases (70%), and anterior to sacrum in three cases (30%); at the aortic bifurcation, SHP strided over left iliac artery from left-hand side, then located in front of sacrum in four cases (40%), and sifted to the left at the lumbar sacral promontory in six cases (60%); from both anatomic and histological view, the autonomic nerve plexus lying in an fascia layer of retroperitoneum. CONCLUSION: At the anterior approach lumbar surgery of trans-peritoneum, we should choose the right-hand side incision; the SHP should be pushed aside carefully from right to left along intervertebral disc. The accurate surgical plane was at the deeper layer of autonomical nerve fascia; we also could lift the complete autonomical nerve layer which lies behind the aorta and lumbar sacral promontory, so that the autonomic nerve could be preserved.

Clinical anatomic study of the lower lumbar anterolateral vein: with respect to retroperitoneal endoscopic surgery.

OBJECTIVE: To study the anatomy of veins of the lower lumbar spine and provide the anatomic basement for laparoscopic lumbar surgery. METHODS: A total of 15 formaldehyde-preserved cadavers were studied with special attention to the variety and surrounding structure of ascending lumbar vein (ALV) and iliolumbar veins (ILV), and their relationship with lumbar plexus. RESULTS: ALV and ILV can be found on every sides, which have four variants including separate entry and common entry. The ascending vein and iliolumbar vein separately enter common iliac vein in 18 cases, and as a common stem enter the common iliac vein in 12 cases. Retracting common iliac vein medially both the ascending lumbar and the iliolumbar veins are always at risk of avulsion on exposure of the disc space. The injury of obturator nerve and lumbosacral trunk of lumbar plexus should be avoided. CONCLUSION: Awareness of these anatomic variation can prevent the hemorrhage and be helpful for the surgeon in performing a careful ligation of these veins before medial retraction of the common iliac vein. Our findings emphasize the need for proper dissection of ALV and ILV before ligature during exposure of the lower lumbar spine.

[The clinic anatomy of lumbar plexus in the lumbar anterolaterally approach minimally invasive surgery].

OBJECTIVE: To provide anatomic data for reducing lumbar plexus nerve injury. METHODS: The applied anatomy of lumbar plexus was studied by 15 formaldehyde-preserved cadavers, two groups of sectional images of lumbar segment and three series of virtual chinese human dataset. RESULTS: Arrangement of the lumbar nerve was regular. From anterior view, lumbar plexus nerve arranged from lateral to medial from L2 to L5; from lateral view, lumbar nerve arrange from ventral to dorsal from L2 to L5. The angle degree between the lumbar nerve and lumbar increased from L1 to L5. The lumbar plexus nerve was revealed to be in close contact with transverse process. By sectional anatomy, all parts of the lumbar plexus nerve were located in the dorsal third of the psoas major. The safety zone of the psoas major to prevent nerve injuries was ventrally 2/3. CONCLUSIONS: Psoas major can be considered as surgery landmark when expose the lateral anterior of lumbar by incising the psoas muscle. Incising the psoas muscle ventral 2/3 can prevent lumbar plexus injury. Transverse process can be considered as landmark for the position of lumbar plexus in operation.

Anatomical basis of a proximal fasciocutaneous extension of the distal-based posterior interosseous flap that allows exclusion of the proximal posterior interosseous artery.

OBJECTIVE: The objective of this study was to provide anatomical information for the repair of small tissue defects in the hand with posterior interosseous artery chain-link perforator flaps, a proximal fasciocutaneous extension of the distal-based posterior interosseous flap, which allows the exclusion of the proximal posterior interosseous artery. METHODS: Fourteen posterior interosseous artery chain-link perforator flaps taken from human cadavers were studied by the following three methods: latex perfusion for microanatomy analysis, denture material and vinyl chloride mixed packing for cast analysis, and latex perfusion for the production of clearance specimens. Statistical analysis was performed on cutaneous perforators coming from the intermuscular septum of the extensor carpi ulnaris and the extensor digitorum communis. A cluster analysis was conducted to determine the overall distribution of perforators. RESULTS: There are two main clusters of perforators at a relative distance of 21% and 48% along the ulnar head-to-lateral epicondyle interval. On average, the posterior interosseous artery extends six cutaneous perforators through the intermuscular septum of the extensor carpi ulnaris and the extensor digitorum communis. Of these six arteries, two are clinically significant perforators (0.5 mm or more in diameter) and are located 6 ± 2 cm proximal to the head of the ulna and 10 ± 1 cm distal to the lateral epicondyle of the humerus. Their mean diameters are 0.5 ± 0.1 and 0.6 ± 0.1 mm, with pedicle lengths of 16.8 ± 5.1 and 21.2 ± 12.3 mm, respectively. At the two main clusters of perforator-intensive sites, the vessel chains formed by adjacent perforators are parallel to the intermuscular septum of the extensor carpi ulnaris and the extensor digitorum communis. CONCLUSIONS: This study demonstrates that the posterior interosseous artery has two main clusters of perforators in the middle and distal one-fifth of the forearm, which can be used for repairing hand defects with posterior interosseous artery chain-link perforator flaps.

New insights into autonomic nerve preservation in high ligation of the inferior mesenteric artery in laparoscopic surgery for colorectal cancer.

AIM: To take a deeper insight into the relationship between the root of the inferior mesenteric artery (IMA) and the autonomic nerve plexuses around it by cadaveric anatomy and explore anatomical evidence of autonomic nerve preservation in high ligation of the IMA in laparoscopic surgery for colorectal cancer. METHODS: Anatomical dissection was performed on 11 formalin-fixed cadavers and 12 fresh cadavers. Anatomical evidence-based autonomic nerve preservation in high ligation of the IMA was performed in 22 laparoscopic curative resections of colorectal cancer. RESULTS: As the upward continuation of the presacral nerves, the bilateral trunks of SHP had close but different relationships with the root of the IMA. The right trunk of SHP ran relatively far away from the root of IMA. When the apical lymph nodes were dissected close to the root of the IMA along the fascia space in front of the anterior renal fascia, the right trunk of SHP could be kept in suit under the anterior renal fascia. The left descending branches to SHP constituted a natural and constant anatomical landmark of the relationship between the root of IMA and the left autonomic nerves. Proximal to this, the left autonomic nerves surrounded the root of the IMA. Distally, the left trunk of the SHP departed from the root of IMA under the anterior renal fascia. When high ligation of the IMA was performed distal to it, the left trunk of SHP could be preserved. The distance between the left descending branches to SHP and the origin of IMA varied widely from 1.3 cm to 2.3 cm. CONCLUSIONS: The divergences of the bilateral autonomic nerve preservation around the root of the IMA may contribute to provide anatomical evidence for more precise evaluation of the optimal position of high ligation of the IMA in the future.

An anatomical study on the characteristics of cutaneous branches-chain perforator flap with ulnar artery pedicle.

BACKGROUND: The objective of this study was to provide anatomical information for the repair of small tissue defects in the hands and forearms with ulnar artery pedicle cutaneous branches-chain perforator flaps. METHODS: Twelve ulnar artery pedicle cutaneous branches-chain perforator flaps taken from human cadavers were studied using three methods: latex perfusion for microanatomy analysis, denture material and vinyl chloride mixed packing for cast analysis, and polyvinyl alcohol and bismuth oxide perfusion for molybdenum target x-ray arteriography. Statistical analysis was performed on cutaneous perforators with a diameter of 0.2 mm or greater. Cluster analysis was conducted to determine the overall distribution of perforators. RESULTS: There are two main clusters of perforators at a relative distance of 22.34 percent and 58.73 percent along the pisiform bone to the medial epicondyle. Two thick cutaneous perforators extend through the flexor digitorum superficialis and the flexor carpi ulnaris muscle gap, which are located 4.57 ± 0.59 cm proximal to the pisiform bone and 7.73 ± 1.14 cm distal to the medial epicondyle, with diameters of 0.63 ± 0.09 and 0.75 ± 0.15 mm and pedicle lengths of 1.49 ± 0.34 and 1.46 ± 0.54 cm. At the two main clusters of perforator-intensive sites, vessel chains formed by adjacent perforators were parallel to the flexor digitorum superficialis and the flexor carpi ulnaris muscle gap. CONCLUSION: This study demonstrated that the ulnar artery has two main clusters of perforators in the proximal one-third and distal one-fourth of the forearm, which can be used for ulnar artery pedicle cutaneous branches-chain perforator flaps to repair hand and forearm parenchymal defects.

Ligament structures in the tarsal sinus and canal.

BACKGROUND: The concrete anatomy and functional characteristics of the subtalar ligaments have been a matter of debate that some believe has hampered the progress of clinical ligament reconstruction. METHODS: In 32 fresh-frozen cadaver feet, the course of the inferior extensor retinaculum (IER) and other subtalar ligaments was carefully measured and photographed both from the portal of the tarsal sinus and from a posterior view. RESULTS: The IER inserted inside the tarsal sinus and canal by means of 3 roots: a lateral, an intermediate, and a medial one. These roots, along with the tarsal canal, divided the subtalar space into 3 parts. In front of the IER and inside the tarsal sinus, the thick cervical ligament (CL) lay at a 45-degree angle to the calcaneus. Behind the IER and inside the posterior capsule, in most cases (25 of 32 specimens), the posterior capsular ligament (PCaL) lay directly in front of the posterior talocalcaneal facet. Inside the tarsal canal, the fan-shaped medial root of the IER spread from outside upper lateral to lower medial, and the interosseous talocalcaneal ligament (ITCL) ran from upper medial to lower lateral; fibers of these 2 ligaments blended tightly together to form a V-shaped ligament complex. Just anterior to this complex in some cases (20 of 32 specimens), a short narrow upright ligament, the tarsal canal ligament (TCL), was located behind the middle talocalcaneal joint. CONCLUSION: The results of this study show that the CL is the primary ligament in the tarsal sinus and that the ITCL is a thin single band rather than a strong bilaminar ligament located inside the tarsal canal. Instead, the medial root of the IER is the primary ligamentous structure in the tarsal canal. CLINICAL RELEVANCE: The anatomical description provided here may provide a more accurate theoretical foundation for clinical subtalar stability restoration.

[Anatomical observation on surgical spaces related to laparoscopic right hemicolectomy].

OBJECTIVE: To explore regional anatomy of fasciae and spaces related to laparoscopic right hemicolectomy (LRC). METHODS: Seven cadavers and 49 patients undergoing LRC for cancer were observed. Computed tomography (CT) images of patients and healthy individuals were reviewed. RESULTS: Between ascending mesocolon and prerenal fascia (PRF), there was a right retrocolic space (RRCS), which communicated in all directions. Anterior, posterior, medial, lateral, cranial, and caudal boundaries of the RRCS were ascending mesocolon, PRF, superior mesenteric vein, peritoneal reflexion at right paracolic sulcus, inferior margin of transverse part of duodenum, and inferior margin of the mesentery root, respectively. Between transverse mesocolon and pancreas and duodenum, there was a transverse retrocolic space (TRCS), which was bounded cranially by root of transverse mesocolon. On CT images of healthy individuals, PRF was noted as slender line of middle density, continuing to transverse fascia, and the retrocolic spaces were unidentifiable. For patients with right colon cancer, PRF and right retrocolic space might be easier to be identified. CONCLUSIONS: The RRCS and the TRCS are natural surgical spaces. The PRF is natural surgical plane in LRC for cancer.

[Anatomic observation of annular distribution of perirectal fascia and space around the mesorectum].

OBJECTIVE: To explore the regional anatomy of the rectum including the perirectal fasciae and spaces. METHODS: Twenty-one cadavers (15 males and 6 females) were embalmed and their vessels were visualized by injection with color dye. From the cadavers, 30 hemipelvis and 6 three-quarter pelvis were harvested. The perirectal fasciae and spaces and the pelvic autonomic nerves were dissected and examined. RESULTS: Three tissue layers were dissected from the inside to the periphery including the proper rectal fascia enveloping the mesorectum, the presacral fascia, and the piriformis fascia fused with the sacral periosteum. The mesorectum comprised 2 parts with the classical posterolateral fat covered by the proper rectal fascia posteriorly and the anterior fat covered by the posterior layer of Denonvilliers fascia anteriorly. Extending anteriorly to the anterior layer of Denonvilliers fascia, the presacral fascia bisected the space between the mesorectum and the piriformis fascia into the retrorectal space and the presacral space. The retrorectal space extended cranially to the left retrocolic space, anterior to the space between the 2 layers of Denonvilliers fascia(prerectal space). CONCLUSIONS: From the inside to the periphery, the proper rectal fascia, the presacral fascia, and the muscular fascia are distributed in an annular pattern around the mesorectum. The presacral fascia divides the perirectal space into 2 annular parts, the central retrorectal space and the peripheral presacral space. The retrorectal space is the ideal surgical plane for total mesorectal excision.

Retrocolic spaces: anatomy of the surgical planes in laparoscopic right hemicolectomy for cancer.

To explore the regional anatomy of the fasciae and spaces around the right-side colon from laparoscopic perspective, we observed the location, extension, and boundaries of the spaces around the right-side colon in seven cadavers and in 49 patients undergoing laparoscopic right hemicolectomy for cancer, and reviewed computed tomography images from patients and healthy individuals. Between the ascending mesocolon and prerenal fascia (PRF), there was a right retrocolic space (RRCS), which extended in all directions. The anterior, posterior, medial, lateral, cranial, and caudal boundaries of the RRCS were the ascending mesocolon, PRF, superior mesenteric vein, right paracolic sulcus, inferior margin of the duodenum, and inferior margin of the mesentery radix, respectively. Between the transverse mesocolon and the pancreas and duodenum, there was a transverse retrocolic space, which was enclosed cranially by the radix of the transverse mesocolon. In CT images, healthy PRF was noted as slender line of middle density, continuing to the transverse fascia. The retrocolic spaces was unidentifiable, unless they were filled with retroperitoneal lesions. The RRCS and transverse retrocolic space are natural surgical planes for laparoscopic right hemicolectomy for cancer. The boundaries of these fusion fascial spaces are the best access, and the PRF is the best guide.

[Preliminary study of an intracavitary convex array probe for detecting distal extracranial internal carotid artery by transoral carotid ultrasonography].

OBJECTIVE: To explore the feasibility of using an intracavitary convex array probe for detecting the distal extracranial internal carotid artery (ICA) by transoral carotid ultrasonography (TOCU). METHODS: Forty patients underwent examinations with bilateral ICA inspected with an intracavitary convex array probe by TOCU to observe the internal diameter, visible length, peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI). RESULTS: Eight of the 40 patients were excluded from the observation for the presence of carotid plaques. The examination was terminated in two patients due to sensitive throat and severe pharyngeal reflex. The rest of the patients completed the examination of the internal diameter, visible length, PSV, EDV and RI, which showed no statistically significant differences among them (P>0.05). CONCLUSION: Using intracavitary convex array probe, the distal extracranial ICA disease can be diagnosed with higher accuracy.

[Preservation of the autonomic nerve in rectal cancer surgery: anatomical factors in ligation of the inferior mesenteric artery].

OBJECTIVE: To evaluate the regional anatomy between the abdominal autonomic nerves including the abdominal aortic plexus (AAP) and the inferior mesenteric artery (IMA), and explore the safe ligation point on the IMA and the optimal dissection method to avoid autonomic nerve injuries. METHODS AND RESULTS: Dissections and observation were carried out on 16 fixed male cadavers. The AAP located in the thin fascia layer covering the surface of the aorta and its branches. No autonomic nerves were found in the area around the root of the IMA, and the point where the IMA and the left trunk of the AAP intersected was highly variable. The left trunk of the AAP adhered more closely to the IMA than to the aorta. CONCLUSIONS: In view of autonomic nerve preservation, the only safe site for ligation of the IMA is at its origin, and no other such sites are available along the IMA trunk and its branches. The IMA and the posterior fascia layer containing the autonomic nerves constitute the optimal surgical plane for IMA ligation, which should be performed following skeletonization of the IMA with careful preservation of the integrity of the posterior fascia layer.