Distal Brachial Artery Perforator flap: a new chimeric option for complex hand and digits defects.

INTRODUCTION: Reconstruction of fingers pose unique challenges, as a thin and flexible flap is needed in order to guarantee a good functional outcome. For the first time, in this report, we present the DBAp (distal brachial artery perforator) flap, based on the distal perforator closer to the medial epicondyle. The DBAp flap was used to reconstruct complex digit defects as free flap, and to cover an elbow defect while raised as a propeller. METHODS: Four patients underwent finger reconstruction (free flaps): two patients presented an unstable finger scar following previous surgery, whereas the other two patients presented a terminalized finger at the level of the middle phalanx. A further patient presented a post-traumatic loss of substance at the elbow and was reconstructed using a perforator propeller DBAP flap. RESULTS: Loss of tissues included skin and subcutaneous tissue in all patients and in one patient it included a bone component. Flap dimensions ranged from 48 to 18 cm2 (average: 32 cm2). Among complications, patient n.2 flap presented a marginal flap necrosis requiring a small skin graft after necrosis debridement. CONCLUSION: The DBAp flap provides a slim, glabrous and pliable skin tissue with a well-hidden donor site scar and thanks to the anatomic location of the distal perforator can be designed to include a vascularized bone graft from the medial epicondyle. Despite the low number of cases, we believe that this flap should be considered as a dependable and effective source for complex reconstructions of both soft tissue and bone in fingers.

Endolymphatic sac surgical anatomy and transmastoid decompression of the sac for the management of Ménière's disease.

BACKGROUND: Decompression of the endolymphatic sac for Ménière's disease gives unpredictable results. This may be because the sac is difficult to identify and decompress accurately without causing surgical trauma. METHODS: In order to test this idea, transmastoid decompression was simulated in 5 cadaver half heads and the anatomy of the endolymphatic sac was reviewed in a further 14 specimens. RESULTS: The endolymphatic sac was found and confirmed by histology in all five simulated decompressions. A newly described feature, a trapezoid thickening of dura, was a useful guide. The review showed that the sac was constant proximally, but variable distally. The posterior semicircular canal, posterior fossa dura and sigmoid sinus are at risk during dissection. CONCLUSION: The endolymphatic sac may be identified on inspection by an overlying patch of dura, thereby reducing exploratory dissection. It is best to decompress the sac as far proximally as possible, whilst protecting the posterior semicircular canal.

Applied anatomy of the latissimus dorsi free flap for refinement in one-stage facial reanimation.

BACKGROUND: The face can be reanimated after long-term paralysis by free microneurovascular tissue transfer. Flaps from gracilis and pectoralis minor usually require a two-stage procedure with a cross-face nerve graft. Latissimus dorsi has a much longer muscular nerve, the thoracodorsal nerve, which could avoid the need for a second cross-face nerve graft. Our hypothesis is that the neurovascular pedicles of small segments of latissimus dorsi would be long enough to reach the opposite side of the face and to provide a reliable blood and nerve supply to the flaps. METHOD: To test this hypothesis the thoracodorsal pedicle and its primary branches were dissected in eleven embalmed cadavers. The segmental vessels and nerves were then traced in a series of simulated flaps approximately 8-10 cm × 2-3 cm by micro-dissection, tissue clearing and histology. RESULTS: The thoracodorsal pedicle is 10-14 cm long to where it enters the muscle, and with intra-muscular dissection small chimeric muscle segments 8-10 cm × 2-3 cm can be raised with a clearly defined neurovascular supply. Using micro-dissection the neurovascular pedicle can be lengthened to reach across the face. Segmental arteries and nerves extended to the distal end of all the flaps examined. Artery, vein and nerve run together and are of substantial diameter. CONCLUSION: Small muscle segments of latissimus dorsi can be raised on long neurovascular pedicles. The vessels and nerves are substantial and the likelihood of surgical complications such as flap necrosis and functional disuse on transplantation appear low. Although in our opinion the use of cross-face nerve grafts and transfer of smaller muscle flaps remains the gold standard in facial reanimation in straightforward cases, the micro-dissected latissimus dorsi flap is a useful option in complex cases of facial reanimation. CLINICAL APPLICATION: Facial reanimation using micro-dissected segments of latissimus dorsi has been performed in four complex cases of facial paralysis.

A cadaveric study of auricular lymphatics and implications for sentinel lymph node biopsy.

Malignant cutaneous tumors of the auricle are known to have a high rate of spread to the regional lymph nodes, and, for this reason, removal of the lymph nodes, for diagnostic or therapeutic purposes, is often required. Recent experience with sentinel node biopsy in cutaneous tumors of the head and neck has questioned the traditional lymphatic pathways and prompted a new study. Lymphatic pathways from the auricle were demonstrated by India ink injection of five auricles in three cadavers followed by block dissection and Spalteholz clearing of en bloc specimens. Lymphatics descend adjacent to the mastoid bone periosteum and lie deep to the insertion of the sternocleidomastoid muscle. There are five different locations for sentinel nodes: superficial parotid, anterior mastoid, infra-auricular parotid, deep to sternocleidomastoid, and lateral mastoid. Two of these nodal locations (anterior and lateral mastoid) may be bypassed by anastomotic pathways. We conclude that, first, echelon lymph nodes lie in five different sites, some bypassed by anastomotic lymphatics. Lymphatics from the ear lie close to the mastoid bone and pass deep to the insertion of sternocleidomastoid where they may be difficult to follow. Sentinel lymph node biopsy for cutaneous tumors of the auricle is possible, but the presence of skip metastases should be considered.

Pressure injection demonstrates points of weakness in the posterior nasal arteries.

OBJECTIVE: To test the hypothesis that potential sites of weakness within normal nasal arteries, when stressed, contribute to the mechanism of epistaxis, we 'stress-tested' nasal arteries in unfixed cadaveric heads, using pressure injection of feeding arteries. MATERIALS AND METHODS: Indian ink with latex was injected into maxillary arteries under high pressure (620 mmHg). Stepwise dissection was carried out and areas showing ink leakage were examined. Control heads were injected at standard embalming pressures (375 mmHg). RESULTS: Ink leakage was found in all heads injected at higher pressure, and was restricted to the nasal mucosa. Histological examination of leakage points demonstrated vessel disruption consistent with dissecting aneurysm formation. DISCUSSION: Results showed that high pressure injection caused leakage from arteries in the posterior nose; the distribution of leakage points was consistent with many clinical investigations. The lesions produced were comparable with our best histopathological model of epistaxis, i.e. dissecting aneurysm formation. This suggests that pre-existing weaknesses in the arterial configuration may exist.

Prevention of paediatric ring avulsions - a cadaveric study.

Finger ring avulsion injuries can be functionally, cosmetically and emotionally devastating for the patient. This cadaveric study assessed a simple way to prevent ring avulsion injuries. Fresh cadaver fingers were used to test the incidence of avulsion injury with ordinary rings and when a single slot was cut in the ring. Intact rings mostly produced significant digital injuries, while the rings with slots did not.

Woodruff's plexus.

OBJECTIVE: To identify the nature of Woodruff's plexus, which has been frequently mentioned in the rhinological literature but has never been properly characterised. STUDY DESIGN AND SETTING: A study using 21 cadaveric specimens, combining microdissection of the mucosa of the posterior part of the inferior meatus, Spalteholz 'clearing' of specimens injected with latex ink, and histological analysis of sections of the inferior meatal mucosa. RESULTS: Microdissection revealed a superficial plexus of thin walled vessels in the inferior meatus, which were also seen in cleared, injected specimens. Histological sections showed these vessels to be large, thin walled veins with very little muscle or fibrous tissue, within a thin mucosa relatively devoid of other structures. CONCLUSION: Woodruff's plexus is a venous plexus in the posterior part of the inferior meatus. SIGNIFICANCE: This is the first time Woodruff's plexus has been properly characterised. Whilst the significance of the plexus itself is uncertain, its long overdue identification as a venous plexus provides a platform for further study and discussion.

Arterial anatomy of the lateral orbital and cheek region and arterial supply to the "peri-zygomatic perforator arteries" flap.

Arterial anatomy of the lateral orbital and cheek region and subsequently of the "peri-zygomatic perforator arteries" flap is described, based upon the dissection of the 24 human cadaver head halves. Each specimen was dissected in subdermal, first fascial and deep level. The subdermal vascular network of lateral orbital and cheek region, its orientation and contributing arteries were studied. Origin, perforation sites and diameters of transverse facial, zygomaticoorbital, zygomaticofacial and zygomaticotemporal arteries were also described and measured. Our findings support the view that the cheek island flap used for lower eyelid is a reverse flow axial pattern flap. It includes arterioles of the transverse facial artery, which are part of the subdermal vascular plexus and are uniformly longitudinally oriented. The flap receives its blood supply via perforators of the zygomaticoorbital, zygomaticofacial and zygomaticotemporal arteries, which are connected via their terminal branches with transverse facial artery.

Blood supply to the first metatarsal head and vessels at risk with a chevron osteotomy.

BACKGROUND: Chevron osteotomy, a commonly performed procedure for the treatment of hallux valgus, results in osteonecrosis of the first metatarsal head in 0% to 20% of cases. The aim of this study was to map out the arrangement of the vascular supply to the first metatarsal head and its relationship to the limbs of the chevron osteotomy. METHODS: Ten cadaveric lower limbs were injected with an India ink-latex mixture, and the feet were dissected to assess the blood supply to the first metatarsal head. The dissection was carried out by tracing the branches of the dorsalis pedis and posterior tibial vessels. A distal chevron osteotomy was mapped, with the limbs of the osteotomy set at an angle of 60 degrees from the geometric center of the first metatarsal head. The relationship of the limbs of the osteotomy to the blood vessels was recorded. RESULTS: The first metatarsal head was found to be supplied by branches from the first dorsal metatarsal, first plantar metatarsal, and medial plantar arteries. The first dorsal metatarsal artery was the dominant vessel among the three arteries in eight specimens. All of the vessels formed a plexus at the plantar-lateral aspect of the metatarsal neck, just proximal to the capsular attachment, with a varying number of branches from the plexus then entering the metatarsal head. The plantar limb of the proposed chevron cuts exited through this plexus of vessels in all specimens. Contrary to the widely held view, only minor vascular branches could be found entering the dorsal aspect of the neck. CONCLUSIONS: The identification of the plantar-lateral corner of the metatarsal neck as the major site of vascular ingress into the first metatarsal head suggests that constructing the chevron osteotomy with a long plantar limb exiting well proximal to the capsular attachment may decrease the postoperative prevalence of osteonecrosis of the first metatarsal head.

The thin circumflex scapular artery perforator flap.

The development of microsurgery has most recently been focused upon the evolution of perforator flaps, with the aim of minimising donor site morbidity, and avoiding the transfer of functionally unnecessary tissues. The vascular basis of perforator flaps also facilitates radical primary thinning prior to flap transfer, when appropriate. Based upon initial clinical observations, cadaveric, and radiological studies, we describe a new, thin, perforator flap based upon the circumflex scapular artery (CSA). A perforator vessel was found to arise within 1.5cm of the CSA bifurcation (arising from the main trunk, or the descending branch). The perforator arborises into the sub-dermal vascular plexus of the dorsal scapular skin, permitting the elevation and primary thinning of a skin flap. This thin flap has been employed in a series of five clinical cases to reconstruct defects of the axilla (two cases of hidradenitis suppurativa; pedicled transfers), and upper limb (one sarcoma, one brachial to radial artery flowthrough revascularisation plus antecubital fossa reconstruction, and one hand reconstruction with a chimeric flap incorporating vascularised bone, fascia, and thin skin flaps; free tissue transfers). No intramuscular perforator dissection is required; pedicle length is 8-10cm and vessel diameter 2-4mm. There was no significant peri-operative complication or flap failure, all donor sites were closed primarily, patient satisfaction was high, and initial reconstructive aims were achieved in all cases. Surgical technique, and the vascular basis of the flap are described. The thin circumflex scapular artery perforator flap requires no intramuscular dissection yet provides high quality skin (whose characteristics can be varied by orientation of the skin paddle), and multiple chimeric options. The donor site is relatively hair-free, has favourable cosmesis and no known functional morbidity. This flap represents a promising addition to the existing range of perforator flaps.

Innervation of vastus lateralis muscle.

The lateral surgical approach to the proximal femur potentially damages the nerve supply to the vastus lateralis (VL) muscle. This study describes the detailed anatomy of the nerve supply to the VL muscle based on dissection of ten cadaveric lower limbs. In all specimens, a single nerve trunk arose from the femoral nerve, which is most subsequently divided into two main divisions. These divisions gave two branches each. These branches coursed from anteriorly and proximally to posteriorly and distally within the muscle. When the muscle was reflected anteriorly from its attachment to the linea aspera, there was no damage to its innervation. Splitting of the VL in the midlateral line of the femur, however, resulted in denervation of the posterior half of the muscle. Precise knowledge of the nerve supply to the VL will help avoid iatrogenic denervation of the muscle in surgical procedures at the proximal femur through the lateral approach.

Effects of thinning the anterolateral thigh flap on the blood supply to the skin.

The anterolateral thigh (ALT) flap is becoming a popular option for reconstructing a variety of soft-tissue defects, especially in the head and neck. Thinning of the flap may extend its usefulness to situations requiring less bulk, and the successful use of this technique has previously been described in the Far East. However, similar results have not yet been produced in the West. To investigate this, it is proposed that 'one-stage thinning of the ALT flap does not disrupt the blood supply to any area of the flap skin'. A series of 10 ALT flaps were raised from Western European cadavers. The arteries of the flaps were injected with Indian ink and latex rubber, and six of the flaps were cleared by the Spalteholz technique. Patterns of dye filling were compared in full-thickness and thinned specimens, and the arterial organisation within the subcutaneous fat was studied. We saw 14 perforators in 10 ALT flap dissections. These arose from the descending branch of the lateral circumflex femoral artery in eight cases and from the transverse branch in two cases. Large branches from the perforator were seen to form an arterial plexus at the level of the deep fascia, which communicates with the subdermal plexus supplying the skin. Further branches arose from the perforator and travelled obliquely through the fat to reach the subdermal plexus. In the thinned cadaver ALT flaps, dye perfusion did not reach the distal portions of the subdermal plexus. There was reduced dye filling in comparison to the full-thickness specimens. Thinning of the ALT flap reduces arterial perfusion in cadaver specimens. This allows rejection of the null hypothesis. The fascial plexus and the oblique vessels supplying the subdermal plexus are likely to be damaged or removed during thinning. This may explain the observed reduction in subdermal-plexus filling in the thinned specimens. In the clinical setting, disruption of the arterial supply in this manner could lead to ischaemia and skin necrosis in thinned flaps. One-stage thinning of the ALT flap may not be advisable in the Western population.

Transthecal digital nerve block. An anatomical appraisal.

Injection studies using methylene blue and latex were used in 60 digits from 40 cadavers to study how anaesthetic fluid injected into the flexor tendon sheath might spread around the proximal part of the finger. The injected solution escaped from the flexor tendon sheath around the vincular vessels which are present near the base and head of the proximal phalanx. Outside the digital canal, the dye flowed smoothly through the perivascular loose areolar tissue and spread alongside the main digital vessels and nerves and their palmar and dorsal branches.

Nerve supply of the breast with special reference to the nipple and areola: Sir Astley Cooper revisited.

Cooper in 1840 described mammary branches from the 2nd-6th intercostal nerves, and noticed that the nipple was supplied by branches which lay close to the surface of the gland. Eckhard (1850) divided the mammary branches into superficial branches to the skin and nipple, and deep branches to the glandular tissue and nipple, but many later authors ignored those findings. After the second World War, cosmetic surgery of the breast made further research critical, as surgeons strove to design operations which would retain its shape and preserve postoperative sensation. Craig and Sykes (1970) described mainly anterior branches from the 3rd, 4th and 5th intercostal nerves passing through the glandular tissue of the breast and along the line of the ducts to the nipple, while Farina et al. (1980) concluded that the nipple was supplied solely by superficial lateral branches of the 4th nerve. Using improvements in dissecting technique learned from microsurgery, Sarhadi et al. (1996) found that the nipple was innervated by the lateral cutaneous branch of the 4th intercostal nerve, by two branches, one passing superficial to the gland, and the other through the retromammary space, and by variable lateral and medial additional branches from the 2nd-5th nerves. These branches came to lie superficially and formed a subdermal plexus under the areola. This account is uncannily close to Cooper's original description; it is a reassuring, if sobering, conclusion that his early account remains one of the most reliable.

An anatomical study of the nerve supply of the breast, including the nipple and areola.

There are widely differing accounts in the literature of the origin, course, and distribution of the nerves to the breast and especially to the nipple and areola. This, together with our own findings at operation, led us to investigate whether the accounts are inaccurate or the nerve supply is very variable or both. 15 breast specimens from dissecting room cadavers, 12 female and 3 male, were dissected to study the nerve supply of the breast in detail. In the female, the breast received its innervation from the lateral and anterior cutaneous branches of the second to the sixth intercostal nerves and from the supraclavicular nerves. On the lateral side in the 12 females, branches from the third (9/12), fourth (12/12) and fifth (4/12), and on the medial side branches from the second (3/12), the third (6/12), the fourth (4/12) and the fifth (2/12) intercostal nerves were traced to a plexus under the areola. Branches from the sixth intercostal nerve supplied the lower part of the breast but there was no direct branch to the nipple. The nerves to the nipple lay in the superficial fascia and passed through the subdermal tissue of the areola to form a plexus under it. The extent of the contribution by each nerve was variable, and it differed even on the left and right of the same cadaver. The nerve often described as passing through the inferolateral part of the breast to reach the nipple is a deep branch from the anterior division of the fourth lateral cutaneous nerve. This was present in 11/12 of the female breasts but it is not the only nerve to reach the plexus under the areola as sometimes claimed. The male breast had a similar nerve supply but the nerves were lying close together, whereas in a female breast they are spread out more widely.

The relative strengths of the rotator cuff muscles. A cadaver study.

We studied five cadaver shoulders to determine the strength relationship of the four rotator cuff muscles. The mean fibre length and volume of each muscle were measured, from which the physiological cross-sectional area was calculated. This value was used to estimate the force which each muscle was capable of generating. The lever arm of each muscle about the humeral head was then measured and the moment exerted was calculated. The strength ratios between the muscles were more or less constant in the five specimens. Subscapularis was the most powerful muscle and contributed 53% of the cuff moment; supraspinatus contributed 14%, infraspinatus 22% and teres minor 10%. The force-generating capacity of the subscapularis was equal to that of the other three muscles combined.