Anton Kerver

The Surgical Anatomy of the Infrapatellar Branch of the Saphenous Nerve in Relation to Incisions for Anteromedial Knee Surgery

BACKGROUND Iatrogenic injury to the infrapatellar branch of the saphenous nerve is a common complication of surgical approaches to the anteromedial side of the knee. A detailed description of the relative anatomic course of the nerve is important to define clinical guidelines and minimize iatrogenic damage during anterior knee surgery. METHODS In twenty embalmed knees, the infrapatellar branch of the saphenous nerve was dissected. With use of a computer-assisted surgical anatomy mapping tool, safe and risk zones, as well as the location-dependent direction of the nerve, were calculated. RESULTS The location of the infrapatellar branch of the saphenous nerve is highly variable, and no definite safe zone could be identified. The infrapatellar branch runs in neither a purely horizontal nor a vertical course. The course of the branch is location-dependent. Medially, it runs a nearly vertical course; medial to the patellar tendon, it has a -45° distal-lateral course; and on the patella and patellar tendon, it runs a close to horizontal-lateral course. Three low risk zones for iatrogenic nerve injury were identified: one is on the medial side of the knee, at the level of the tibial tuberosity, where a -45° oblique incision is least prone to damage the nerves, and two zones are located medial to the patellar apex (cranial and caudal), where close to horizontal incisions are least prone to damage the nerves. CONCLUSIONS The infrapatellar branch of the saphenous nerve is at risk for iatrogenic damage in anteromedial knee surgery, especially when longitudinal incisions are made. There are three low risk zones for a safer anterior approach to the knee. The direction of the infrapatellar branch of the saphenous nerve is location-dependent. To minimize iatrogenic damage to the nerve, the direction of incisions should be parallel to the direction of the nerve when technically possible. CLINICAL RELEVANCE These findings suggest that iatrogenic damage of the infrapatellar branch of the saphenous nerve can be minimized in anteromedial knee surgery when both the location and the location-dependent direction of the nerve are considered when making the skin incision.

The surgical anatomy of the small saphenous vein and adjacent nerves in relation to endovenous thermal ablation.

BACKGROUND Thermal damage to peripheral nerves is a known complication of endovenous thermal ablation (EVA) of the small saphenous vein (SSV). Therefore, the main objective of this anatomic study was to define a safe zone in the lower leg where EVA of the SSV can be performed safely. METHODS The anatomy of the SSV and adjacent nerves was studied in 20 embalmed human specimens. The absolute distances between the SSV and the sural nerve (SN) (closest/nearest branch) were measured over the complete length of the leg (>120 data points per leg), and the presence of the interlaying deep fascia was mapped. The distance between the SSV and the tibial nerve (TN) and the common peroneal nerve was assessed. A new analysis method, computer-assisted surgical anatomy mapping, was used to visualize the gathered data. RESULTS The distance between the SSV and the SN was highly variable. In the proximal one-third of the lower leg, the distance between the vein and the nerve was <5 mm in 70% of the legs. In 95%, the deep fascia was present between the SSV and the SN. In the distal two-thirds of the lower leg, the distance between the vein and the nerve was <5 mm in 90% of the legs. The deep fascia was present between both structures in 15%. In 19 legs, the SN partially ran beneath the deep fascia. In the saphenopopliteal region, the average shortest distance between the SSV and the TN was 4.4 mm. In 20%, the distance was <1 mm. The average, shortest distance between the SSV and the common peroneal nerve was 14.2 mm. The distance was <1 mm in one leg. CONCLUSIONS At the saphenopopliteal region, the TN is at risk during EVA. In the distal two-thirds of the lower leg, the SN is at risk for (thermal) damage due to the small distance to the SSV and the absence of the deep fascia between both structures. The proximal one-third of the lower leg is the optimal region for EVA of the SSV to avoid nerve damage; the fascia between the SSV and the SN is a natural barrier in this region that could preclude (thermal) damage to the nerve.

Surgical Anatomy of the 10th and 11th Intercostal, and Subcostal Nerves: Prevention of Damage During Lumbotomy

PURPOSE In a descriptive, inventorial anatomical study we mapped the course of the 10th and 11th intercostal nerves, and the subcostal nerve in the abdominal wall to determine a safe zone for lumbotomy. MATERIALS AND METHODS We dissected 11 embalmed cadavers, of which 10 were analyzed. The 10th and 11th intercostal nerves, and the subcostal nerve were dissected from the intercostal space to the rectus sheath. Analysis was done using computer assisted surgical anatomy mapping. A safe zone and an incision line with a minimum of nerve crossings were determined. RESULTS The 10th and 11th intercostal nerves were invariably positioned subcostally. The subcostal nerve lay subcostally but caudal to the rib in 4 specimens. The main branches were located between the internal oblique and transverse abdominal muscles. The nerves branched and extensively varied in the abdominal wall. A straight line extended from the superior surface of the 11th and 12th ribs indicated a zone with lower nerve density. In 5 specimens the 10th and 11th intercostal nerves crossed this line from the superior surface of the 11th rib. In 5 specimens neither the 11th intercostal nerve nor the subcostal nerve crossed this extended line from the superior surface of the 12th rib up to 15 cm from the tip of the rib. CONCLUSIONS Damage is inevitable to branches of the 10th or 11th intercostal nerve, or the subcostal nerve during lumbotomy. However, an incision extending from the superior surface of the 11th or 12th rib is less prone to damage these nerves. Closing the abdominal wall in 3 layers with the transverse abdominal muscle separately might prevent damage to neighboring nerves.

Perforating Veins: An Anatomical Approach to Arteriovenous Fistula Performance in the Forearm

OBJECTIVES Arteriovenous fistulae (AVFs) play a key role for people who rely on chronic haemodialysis. Stenosis in the venous outflow of the AVF will cause an alternative route of the subcutaneous blood flow via the deeper venous pathways by means of side branches and the perforating veins (PVs). The purpose for the present study was to define the number and anatomical localisation of the perforating veins in the forearm. METHODS Twenty forearms were dissected to study the venous anatomy. The localisation, size and connections of the perforators were recorded and stored digitally. RESULTS In total, 189 PVs were defined (mean, 9.5 per arm; range, 6-19), with 60 (32%) PVs connected to the cephalic vein, 97 (51%) connections to the basilic vein and 32 (17%) PVs to the median vein of the forearm. Most PVs originate from the basilic vein and connect with the ulnar venae comitans. The cephalic vein connects equally to the radial venae comitans, interossea veins and the muscles. CONCLUSION The cephalic vein has the fewest PVs and almost a third of them connect to the muscles. This is probably important for the maturation of the AVF, the superficial flow volume and the accessibility for puncture.

An anatomical study of the ECRL and ECRB: feasibility of developing a preoperative test for evaluating the strength of the individual wrist extensors

BACKGROUND Tendon transfers are essential for reconstruction of hand function in tetraplegic patients. To transfer the extensor carpi radialis longus (ECRL), the extensor carpi radialis brevis (ECRB) has to be sufficiently strong. However, there is currently no reliable clinical test to individually analyse both muscles. In order to develop a reliable preoperative clinical test, the anatomy of the muscle (innervation) areas of ECRB, ECRL and brachio-radialis (BR) was examined. METHODS In 20 arms, the ECRB, ECRL and BR were dissected and localised. Subsequently, muscle-innervation points were mapped and categorised. A novel method, computer-assisted surgical anatomy mapping (CASAM), was used to visualise muscle areas and innervation points in a computed arm with average dimensions. RESULTS For both ECRL and ECRB a 100% area could be identified, a specific area in the computed average arm in which the muscle was present for all 20 arms. For the ECRL, this area was situated at 16% of the distance between the lateral epicondyle and the deltoid muscle insertion. The ECRB 100% area was 5 times bigger than that of the ECRL and was located at 40% of the distance between the lateral epicondyle and the radial styloid process. The ECRL and BR showed one to three innervation points, the ECRB one to four. In 47% of the cases, there was a combined nerve branch innervating both the ECRL and the ECRB. CONCLUSIONS It is feasible to develop a preoperative test; the 100% areas can be used for needle electromyography (EMG) or local anaesthetic muscle injections.

Transorale endoskopische Thyreoidektomie

ZusammenfassungHintergrundDas Zugangstrauma bei der Thyreoidektomie wurde durch die Entwicklung minimal-invasiver Verfahren verringert. Extrazervikale Zugänge haben zwar die sichtbare Narbe verlagert, sind aber aufgrund der Dissektionen maximal-invasiv. Daher soll mit dem transoralen Zugang zur Thyreoidektomie ein auf das Notwendige reduzierter minimal-invasiver Zugang anhand anatomischer Präparationsebenen etabliert werden.Material und MethodenPräklinisch erfolgten Dissektionen an 3 humanen Präparaten zur Identifikation „sicherer“ Regionen der vorderen Halsregion sowie der Submandibularloge. Die Mundbodenregion wurde auf relevante vaskuläre und nervale Strukturen hin untersucht. Die endoskopische minimal-invasive Thyreoidektomie erfolgte an 5 weiteren Präparaten mit anschließender Dissektion.ErgebnisseFür einen sicheren Zugang wurde ein sublingual in der Mittellinie platzierter Optiktrokar eingesetzt. Die Schilddrüsenregion war ohne Tangierung relevanter vaskulärer oder neuraler Strukturen zu erreichen. Zwei Arbeitstrokare wurden im Mundvorhof positioniert. Zugangs- und Präparationsebene liegen subplatysmal und somit in einer avaskulären Gleitschicht. Auf diese Weise kann das Operationsgebiet schnell, einfach und sicher erreicht werden.SchlussfolgerungMinimale Invasivität, anatomiegerechter Zugang und schichtgerechtes Arbeiten bilden die Rationale für einen transoralen Zugang zur Schilddrüsenloge. Es konnten anhand anatomischer Dissektionen die Grundlagen einer weiteren Prozedur im Rahmen der „natural orifice surgery“ (NOS) gezeigt werden.AbstractBackgroundSurgical access trauma in thyroidectomy has been minimized by the adoption of minimally invasive techniques. Extracervical approaches moved the incision lines outside of the visible neck region. However, because of the extensive dissection they no longer comply with the term minimally invasive. Therefore, our goal was to reduce the access trauma and establish a non-traumatic approach according to surgical planes for endoscopic minimally invasive thyroidectomy: the transoral approach.Material and methodsIn a preclinical investigation anatomical dissection was performed on three human cadavers to visualize anatomical relationships and identify safe zones of access to the anterior neck and the submandibular regions. The investigation focused on relevant vascular and neural structures in the floor of mouth. Endoscopic minimally invasive thyroidectomy was additionally performed in five specimens with anatomical dissections for the evaluation of collateral damage.ResultsFor a safe approach the optic trocar can be placed sublingually in the midline as there are no relevant vascular or neural structures on the way to the thyroid region. The working trocars can be placed bilaterally in the oral vestibule behind the canine teeth. In this way access and dissection plane are placed directly in an avascular subplatysmal area and the pretracheal working space can be reached easily, safe and fast.ConclusionsMinimum impact and a gentle dissection according to anatomical planes are the rational for the transoral route to the thyroid gland. Thus based on anatomical dissections the foundations of a novel procedure in the context of natural orifice surgery (NOS) could be established.BACKGROUND Surgical access trauma in thyroidectomy has been minimized by the adoption of minimally invasive techniques. Extracervical approaches moved the incision lines outside of the visible neck region. However, because of the extensive dissection they no longer comply with the term minimally invasive. Therefore, our goal was to reduce the access trauma and establish a non-traumatic approach according to surgical planes for endoscopic minimally invasive thyroidectomy: the transoral approach. MATERIAL AND METHODS In a preclinical investigation anatomical dissection was performed on three human cadavers to visualize anatomical relationships and identify safe zones of access to the anterior neck and the submandibular regions. The investigation focused on relevant vascular and neural structures in the floor of mouth. Endoscopic minimally invasive thyroidectomy was additionally performed in five specimens with anatomical dissections for the evaluation of collateral damage. RESULTS For a safe approach the optic trocar can be placed sublingually in the midline as there are no relevant vascular or neural structures on the way to the thyroid region. The working trocars can be placed bilaterally in the oral vestibule behind the canine teeth. In this way access and dissection plane are placed directly in an avascular subplatysmal area and the pretracheal working space can be reached easily, safe and fast. CONCLUSIONS Minimum impact and a gentle dissection according to anatomical planes are the rational for the transoral route to the thyroid gland. Thus based on anatomical dissections the foundations of a novel procedure in the context of natural orifice surgery (NOS) could be established.

[Transoral endoscopic thyroidectomy : Part 2: Surgical technique].

BACKGROUND Thyroid surgery is one of the newest fields for application of video-assisted surgery. The majority of approaches must choose between optimizing cosmetic results by hiding scars in the chest and axillary region while maximizing tissue dissection and post-operative pain versus having a visible cervical scar with minimal tissue dissection. In an effort to minimize surgical trauma and to achieve an optimal cosmetic result we investigated the transoral approach to the thyroid. MATERIAL AND METHODS In three cadavers the safety and reproducibility to access and resect the thyroid gland were assessed according to a defined road map. The surgical procedure itself was performed on two further cadavers with the help of one 5 mm trocar and two 3 mm trocars which were introduced bilaterally through the floor of mouth and the oral vestibule. A subplatysmal working space was created by blunt dissection and CO(2) insufflation to a pressure of 4-6 mmHg. Division of the median raphe of the neck muscles was followed by exposure of the thyroid gland. In the next step the isthmus was transected, the upper pole arteries dissected and divided and the medial thyroid vein cut close to the gland. Thyroid resection was performed from cranial to caudal and the specimen was removed transorally through the 5 mm midline incision. RESULTS Description of landmarks of the surgical steps and dissection of defined anatomic structures could be achieved. Unilateral subtotal thyroid resection could be successfully performed without any additional skin incisions in 59 min. Postoperatively performed anatomical dissection showed intact surrounding structures. CONCLUSION Our results demonstrate the feasibility and safety of a transoral access for thyroidectomy. In comparison to other minimally invasive thyroidectomy access procedures, the transoral approach is minimally invasive and at the same time cosmetically optimal.

[Transoral endoscopic thyroidectomy. Part 1: rationale and anatomical studies].

ZusammenfassungHintergrundDas Zugangstrauma bei der Thyreoidektomie wurde durch die Entwicklung minimal-invasiver Verfahren verringert. Extrazervikale Zugänge haben zwar die sichtbare Narbe verlagert, sind aber aufgrund der Dissektionen maximal-invasiv. Daher soll mit dem transoralen Zugang zur Thyreoidektomie ein auf das Notwendige reduzierter minimal-invasiver Zugang anhand anatomischer Präparationsebenen etabliert werden.Material und MethodenPräklinisch erfolgten Dissektionen an 3 humanen Präparaten zur Identifikation „sicherer“ Regionen der vorderen Halsregion sowie der Submandibularloge. Die Mundbodenregion wurde auf relevante vaskuläre und nervale Strukturen hin untersucht. Die endoskopische minimal-invasive Thyreoidektomie erfolgte an 5 weiteren Präparaten mit anschließender Dissektion.ErgebnisseFür einen sicheren Zugang wurde ein sublingual in der Mittellinie platzierter Optiktrokar eingesetzt. Die Schilddrüsenregion war ohne Tangierung relevanter vaskulärer oder neuraler Strukturen zu erreichen. Zwei Arbeitstrokare wurden im Mundvorhof positioniert. Zugangs- und Präparationsebene liegen subplatysmal und somit in einer avaskulären Gleitschicht. Auf diese Weise kann das Operationsgebiet schnell, einfach und sicher erreicht werden.SchlussfolgerungMinimale Invasivität, anatomiegerechter Zugang und schichtgerechtes Arbeiten bilden die Rationale für einen transoralen Zugang zur Schilddrüsenloge. Es konnten anhand anatomischer Dissektionen die Grundlagen einer weiteren Prozedur im Rahmen der „natural orifice surgery“ (NOS) gezeigt werden.AbstractBackgroundSurgical access trauma in thyroidectomy has been minimized by the adoption of minimally invasive techniques. Extracervical approaches moved the incision lines outside of the visible neck region. However, because of the extensive dissection they no longer comply with the term minimally invasive. Therefore, our goal was to reduce the access trauma and establish a non-traumatic approach according to surgical planes for endoscopic minimally invasive thyroidectomy: the transoral approach.Material and methodsIn a preclinical investigation anatomical dissection was performed on three human cadavers to visualize anatomical relationships and identify safe zones of access to the anterior neck and the submandibular regions. The investigation focused on relevant vascular and neural structures in the floor of mouth. Endoscopic minimally invasive thyroidectomy was additionally performed in five specimens with anatomical dissections for the evaluation of collateral damage.ResultsFor a safe approach the optic trocar can be placed sublingually in the midline as there are no relevant vascular or neural structures on the way to the thyroid region. The working trocars can be placed bilaterally in the oral vestibule behind the canine teeth. In this way access and dissection plane are placed directly in an avascular subplatysmal area and the pretracheal working space can be reached easily, safe and fast.ConclusionsMinimum impact and a gentle dissection according to anatomical planes are the rational for the transoral route to the thyroid gland. Thus based on anatomical dissections the foundations of a novel procedure in the context of natural orifice surgery (NOS) could be established.BACKGROUND Surgical access trauma in thyroidectomy has been minimized by the adoption of minimally invasive techniques. Extracervical approaches moved the incision lines outside of the visible neck region. However, because of the extensive dissection they no longer comply with the term minimally invasive. Therefore, our goal was to reduce the access trauma and establish a non-traumatic approach according to surgical planes for endoscopic minimally invasive thyroidectomy: the transoral approach. MATERIAL AND METHODS In a preclinical investigation anatomical dissection was performed on three human cadavers to visualize anatomical relationships and identify safe zones of access to the anterior neck and the submandibular regions. The investigation focused on relevant vascular and neural structures in the floor of mouth. Endoscopic minimally invasive thyroidectomy was additionally performed in five specimens with anatomical dissections for the evaluation of collateral damage. RESULTS For a safe approach the optic trocar can be placed sublingually in the midline as there are no relevant vascular or neural structures on the way to the thyroid region. The working trocars can be placed bilaterally in the oral vestibule behind the canine teeth. In this way access and dissection plane are placed directly in an avascular subplatysmal area and the pretracheal working space can be reached easily, safe and fast. CONCLUSIONS Minimum impact and a gentle dissection according to anatomical planes are the rational for the transoral route to the thyroid gland. Thus based on anatomical dissections the foundations of a novel procedure in the context of natural orifice surgery (NOS) could be established.

Transorale endoskopische Thyreoidektomie@@@Transoral endoscopic thyroidectomy: Teil 1: Rationale und anatomische Studien@@@Part 1: Rationale and anatomical studies

ZusammenfassungHintergrundDas Zugangstrauma bei der Thyreoidektomie wurde durch die Entwicklung minimal-invasiver Verfahren verringert. Extrazervikale Zugänge haben zwar die sichtbare Narbe verlagert, sind aber aufgrund der Dissektionen maximal-invasiv. Daher soll mit dem transoralen Zugang zur Thyreoidektomie ein auf das Notwendige reduzierter minimal-invasiver Zugang anhand anatomischer Präparationsebenen etabliert werden.Material und MethodenPräklinisch erfolgten Dissektionen an 3 humanen Präparaten zur Identifikation „sicherer“ Regionen der vorderen Halsregion sowie der Submandibularloge. Die Mundbodenregion wurde auf relevante vaskuläre und nervale Strukturen hin untersucht. Die endoskopische minimal-invasive Thyreoidektomie erfolgte an 5 weiteren Präparaten mit anschließender Dissektion.ErgebnisseFür einen sicheren Zugang wurde ein sublingual in der Mittellinie platzierter Optiktrokar eingesetzt. Die Schilddrüsenregion war ohne Tangierung relevanter vaskulärer oder neuraler Strukturen zu erreichen. Zwei Arbeitstrokare wurden im Mundvorhof positioniert. Zugangs- und Präparationsebene liegen subplatysmal und somit in einer avaskulären Gleitschicht. Auf diese Weise kann das Operationsgebiet schnell, einfach und sicher erreicht werden.SchlussfolgerungMinimale Invasivität, anatomiegerechter Zugang und schichtgerechtes Arbeiten bilden die Rationale für einen transoralen Zugang zur Schilddrüsenloge. Es konnten anhand anatomischer Dissektionen die Grundlagen einer weiteren Prozedur im Rahmen der „natural orifice surgery“ (NOS) gezeigt werden.AbstractBackgroundSurgical access trauma in thyroidectomy has been minimized by the adoption of minimally invasive techniques. Extracervical approaches moved the incision lines outside of the visible neck region. However, because of the extensive dissection they no longer comply with the term minimally invasive. Therefore, our goal was to reduce the access trauma and establish a non-traumatic approach according to surgical planes for endoscopic minimally invasive thyroidectomy: the transoral approach.Material and methodsIn a preclinical investigation anatomical dissection was performed on three human cadavers to visualize anatomical relationships and identify safe zones of access to the anterior neck and the submandibular regions. The investigation focused on relevant vascular and neural structures in the floor of mouth. Endoscopic minimally invasive thyroidectomy was additionally performed in five specimens with anatomical dissections for the evaluation of collateral damage.ResultsFor a safe approach the optic trocar can be placed sublingually in the midline as there are no relevant vascular or neural structures on the way to the thyroid region. The working trocars can be placed bilaterally in the oral vestibule behind the canine teeth. In this way access and dissection plane are placed directly in an avascular subplatysmal area and the pretracheal working space can be reached easily, safe and fast.ConclusionsMinimum impact and a gentle dissection according to anatomical planes are the rational for the transoral route to the thyroid gland. Thus based on anatomical dissections the foundations of a novel procedure in the context of natural orifice surgery (NOS) could be established.BACKGROUND Surgical access trauma in thyroidectomy has been minimized by the adoption of minimally invasive techniques. Extracervical approaches moved the incision lines outside of the visible neck region. However, because of the extensive dissection they no longer comply with the term minimally invasive. Therefore, our goal was to reduce the access trauma and establish a non-traumatic approach according to surgical planes for endoscopic minimally invasive thyroidectomy: the transoral approach. MATERIAL AND METHODS In a preclinical investigation anatomical dissection was performed on three human cadavers to visualize anatomical relationships and identify safe zones of access to the anterior neck and the submandibular regions. The investigation focused on relevant vascular and neural structures in the floor of mouth. Endoscopic minimally invasive thyroidectomy was additionally performed in five specimens with anatomical dissections for the evaluation of collateral damage. RESULTS For a safe approach the optic trocar can be placed sublingually in the midline as there are no relevant vascular or neural structures on the way to the thyroid region. The working trocars can be placed bilaterally in the oral vestibule behind the canine teeth. In this way access and dissection plane are placed directly in an avascular subplatysmal area and the pretracheal working space can be reached easily, safe and fast. CONCLUSIONS Minimum impact and a gentle dissection according to anatomical planes are the rational for the transoral route to the thyroid gland. Thus based on anatomical dissections the foundations of a novel procedure in the context of natural orifice surgery (NOS) could be established.