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Biomedical subjects

K E Bos

Publications and source records attributed to K E Bos.

At least 19 recordsLinked to original sources
PubMed2002

Three-dimensional carpal kinematics in vivo.

OBJECTIVE: The purpose of this study was to accurately quantify three-dimensional in vivo kinematics of all carpal bones in flexion and extension and radial and ulnar deviation. DESIGN AND METHODS: The right wrists of 11 healthy volunteers were imaged by spiral CT with rotational increments of 5 degrees during ulnar-radial deviation and of five of them also during flexion-extension motion. One regular-dose scan was used and the subsequent scans during wrist motion were performed with one-tenth of the regular dose. A three-dimensional matching technique using the internal structure of the bones was developed to trace the relative translations and rotations of the carpal bones very accurately. RESULTS: Most of our results are in concordance with previously published in vitro data. We could, among others, substantiate proof to the statement that there is more than one kinematic pattern of the scaphoid. Furthermore, we could accurately describe small adaptive intercarpal motions in vivo of the distal carpal row. CONCLUSIONS: To our knowledge, this is the first time the three-dimensional in vivo kinematics of all eight carpal bones is quantified accurately and non-invasively. RELEVANCE: Kinematics of an injured wrist can be compared to these reference data. It may become possible that in this way a ligament lesion can be detected with high specificity and sensitivity, and that no other diagnostic modality will be needed. With these data we made animations with which the complex movements of the bones during different motions of the wrist can be viewed. In the future it may become possible that this analysis provides valuable information on the long-term results of operative interventions and possibly predicts results of operative techniques.

Adult↗
PubMed2001

Tension decrease during skin stretching in undermined versus not undermined skin: an experimental study in piglets.

In a controlled study using 15 piglets, the efficacy of skin stretching using a skin stretching device was tested by quantifying the tension decrease during skin stretching in undermined and not undermined wounds. The viability of the skin margins was examined in both situations. Thirty standardized wounds was created: around 15 wounds on one flank, the surrounding skin was undermined; whereas around the 15 wounds on the opposite flank, the surrounding skin was not undermined. The force required to close the 9 x 9 cm defect was measured at the beginning, after undermining, and after 30 minutes of skin stretching. Also examined was the wound healing after 1 day and 1 week. A tension decrease of 3.02 N (13.6 percent reduction of the total force that is required to close the wound at the beginning) was seen due to undermining the surrounding skin. Skin stretching for 30 minutes without undermining the skin showed a tension decrease of 6.10 N (26.5 percent). Therefore, the tension decrease due to skin stretching was twice as high in comparison with undermining the skin margins alone. This has been statistically proven to be significant (-d (difference) = 3.08, 95 percent confidence interval = 2.16; 4.00, p < 0.001). When the undermined skin of the wound was stretched for 30 minutes, we measured a total tension decrease of 7.60 N (34.1 percent). There was a statistically significant but small difference in total tension decrease as a result of undermining combined with skin stretching in comparison with skin stretching without undermining (-d = 1.51, 95 percent confidence interval = 0.77; 2.23, p < 0.001). Undermining the surrounding skin involved cutting musculocutaneous perforating vessels. Looking at the viability of the skin, seven wounds, all found in the undermined group, showed skin necrosis after 1 week. Excessive seroma formation was seen in all wounds around which the skin was undermined. In the not undermined wounds, there were no problems in wound healing. In conclusion, skin stretching for only 30 minutes using a skin stretching device significantly reduces wound closing tension. The additional advantage of skin stretching over that of undermining alone is clearly shown. Undermining the wound margins before skin stretching gives a small additional tension decrease but has well-known complications, such as skin-edge necrosis and seroma formation.

Animals↗
PubMed2001

Minnaar type 1 symptomatic lunotriquetral coalition: a report of nine patients.

Coalition of carpal bones is relatively common. It most frequently involves the lunate and triquetrum. This finding is almost always coincidental and asymptomatic. The fusion also can be incomplete, however, resembling a pseudarthrosis, and these patients can become symptomatic. To the best of our knowledge only 6 patients with a symptomatic Minnaar type 1 lunotriquetral coalition have been described in the literature. We present an additional nine symptomatic patients (12 wrists) with this type of coalition. A lunotriquetral arthrodesis was performed in 5 cases. In 3 cases a proximal row carpectomy was performed.

Adult↗
PubMed2001

Pisiform kinematics in vivo.

The purpose of this study was to quantify in vivo pisiform kinematics. Wrists of healthy volunteers were imaged by spiral computed tomography during ulnar-radial deviation (n = 11) and during flexion-extension (n = 5). Relative translations and rotations of the carpal bones were determined by using a 3-dimensional matching technique. The error of this registration procedure was less than 0.5 mm for translation and 0.4 degrees for rotation. With radial wrist deviation the pisiform flexes while the triquetrum extends; with ulnar deviation the triquetrum shows more ulnar deviation and extension. With wrist extension the pisiform translates over the distal part of the triquetrum while being pressed against it. With flexion the pisiform moves away from the triquetrum while translating proximally. These in vivo findings provide a further explanation for certain clinical entities, such as degenerative changes of the pisotriquetral joint, and may be used as a reference for normal kinematics of the pisiform.

Adult↗
PubMed2001

Modeling a fibula transplant in mandibular reconstructions: evaluation of the effects of a minimal number of osteotomies on the contour of the jaw.

The fibula osteocutaneous free flap has become the preferred method for most cases of mandibular reconstruction after oncologic surgical ablation. To recreate the parabolic form of the mandible, the fibula has to be divided up into segments using a closed wedge osteotomy technique. The number of osteotomies is preferably kept to a minimum so that segmental periosteal circulation is not compromised and also to keep operating time to a minimum. The limited number of osteotomies creates an angular contour. The aim of this study was to establish the degree to which overcorrection or undercorrection would occur when a subtotal reconstruction from ramus to ramus was simulated using five bony segments and four osteotomies. The study was carried out using 30 preserved jaws; the contour lines of the jaws were transferred onto tracing paper using a cardboard template. The contour of the mandible was divided into five sections (ramus, body, symphysis, body, and ramus). Because of the cutting off of the curvature in the original jaw outline, the lateral side of the body will become narrower and the chin broader. This also results in an underprojection (displacement) of the chin. To follow the original contour of the jaw as accurately as possible, all these anomalies must be minimized. The amount of under- and overprojection is calculated for a displacement of 1.0, 1.5, 2.5, 5.0, 7.5, and 10 mm of the chin. The most accurate reconstruction of the mandibular contour is achieved with a displacement of 1.5 or 2.5 mm. To preserve sufficient periosteal circulation, the minimum width of bone segments must be 15 mm or more. This concerns especially the symphysis section. On the basis of a fibula thickness of 14 mm, the internal bone width of the symphysis section is calculated. With a displacement of 1.5 mm, the average internal width of the bone segment is 14.8 mm, with a range of 9.9 to 23.0 mm (95 percent confidence interval, 12.8 to 16.7 mm). Therefore, a displacement of 2.5 mm with an internal bone width of 16.4 mm is preferred (range, 11.9 to 24.8 mm; 95 percent confidence interval, 15.5 to 18.2 mm). The loss of lateral projection is minimal (5.8 mm) and the resulting chin width is acceptable (average, 35.0 mm). In conclusion, we propose that in a subtotal procedure, an acceptable jaw reconstruction can be achieved with a limited number of osteotomies. The bone length of the symphysis section remains within safe limits. If the defect is of limited dimensions, then the resulting jaw contour is even more accurate.

Anthropometry↗
PubMed2001

Fine motor assessment in chronic wrist pain: the role of adapted motor control.

OBJECTIVE: To show whether a difference in fine motor control exists between patients with chronic, undiagnosed wrist pain (CUWP) and healthy controls. Furthermore, a method to assess fine motor function of the wrist is evaluated. DESIGN: A case-control study. SETTING: The Academic Medical Center in Amsterdam, the Netherlands. SUBJECTS: Twenty-seven CUWP patients were compared with 50 healthy control subjects. INTERVENTIONS: Subjects performed horizontal stroke patterns on a digital writing tablet connected to a computer. The control subjects were tested twice to obtain test-retest reliability. A visual analogue scale was used to assess subjective pain. MAIN OUTCOME MEASURES: Fluency of movement and average velocity were measured. Intraclass correlation, ANOVA repeated measures statistics and Pearson correlation were calculated. RESULTS: There is a significant difference in fluency of motion between patients and controls, possibly due to a disturbed motor control, since there is no relationship between pain and test score, nor do CUWP patients have any abnormality in the wrist that can explain the disturbance in motor function. The test method is reliable (ICC = 0.78) and valid. CONCLUSIONS: The disturbed fine motor control in CUWP patients is suggested to maintain chronic wrist pain through 'strain injury, causing' pain evasive adaptation of the motor control system. This might lead to new perspectives regarding treatment of CUWP patients.

Adaptation, Physiological↗
PubMed2001

Fixation methods in mandibular reconstruction using fibula grafts: a comparative study into the relative strength of three different types of osteosynthesis.

BACKGROUND: Bone staples made of a nickel titanium alloy exert dynamic compression, require little dissection, and may provide an alternative to conventional fixation in mandibular reconstruction with a free vascularized fibula graft. METHODS: To evaluate its stability relative to conventional methods of fixation with interosseous wires or miniplates, an in vitro model using beech dowels was developed. Torsional stiffness and strength and compression stiffness and strength were examined. RESULTS: The compression test results showed that maximum strength of interosseous wires is significantly less than memory staples, which in turn are significantly weaker than titanium miniplates. Miniplates are significantly the most rigid form of fixation. Torsional testing showed no significant difference in strength between staples and miniplates and only a marginal difference in elasticity. Interosseous wires show a rapid decrease of strength and rigidity during torsional stress. CONCLUSION: When considering interosseous wires the least and miniplates the most stable form of fixation by which bone healing can occur, memory staples can provide enough stability to ensure consolidation.

Bone Plates↗
PubMed2000

[Fifty years of plastic surgery in the Netherlands. VI. Microsurgery].

Use of the operating microscope created many new possibilities in plastic, reconstructive and hand surgery. Initially most work was done in digital replantation and, somewhat later, in transfers of toes for reconstruction of amputated thumbs. Microvascular surgery, however, appeared to be a technique suitable for more applications. Anatomical research of the blood supply of skin, fascia, muscle and bone identified flaps that could be carried by pedicle vessels. Transfer of these flaps and revascularization by microvascular anastomoses of the pedicle vessels set the stage for free flaps. In a few decades microsurgical techniques in plastic surgery fully matured. With free flap surgery single-stage and complex reconstructions could be achieved leading to earlier mobilization and better restoration of function with a shorter hospital stay. Today, microvascular free tissue transfer is an essential part of plastic and reconstructive surgery. Further advances in microsurgery and free tissue transfers deserve to be mentioned: pre-fabrication of free flaps, reduction of donor site morbidity, development of artificial conduits and instrumentation and finally homologous transplantations.

Hand Injuries↗
PubMed1999

Tarsal autografts for reconstruction of the scapholunate interosseous ligament: a biomechanical study.

A biomechanical cadaver study was performed to identify a potential bone-ligament-bone autograft from the foot for reconstruction of the scapholunate interosseous ligament (SLIL). In this study the biomechanical properties of 9 dorsal tarsal ligaments and the anterior tibiofibular ligament were investigated and compared with those of the dorsal part of the SLIL. Fifteen fresh-frozen human cadaver feet and 14 fresh-frozen human cadaver wrists were used. In a Monsanto Tensometer testing apparatus (Monsanto Limited Instruments, Dorean Swindon, England) the complexes were uniaxially elongated at a constant velocity of 6.35 mm/min until rupture occurred. The stiffness and strength values for each tarsal ligament were calculated and compared with those of the dorsal part of the SL ligament. Analysis indicated that the third dorsal tarsometatarsal ligament (143 +/- 42 N) and the dorsal calcaneocuboid ligament (149 +/- 41 N) were comparable to the dorsal part of the SL ligament (141 +/- 20 N) while all other ligaments were stronger. The stiffness values of the third dorsal tarsometatarsal ligament (67 +/- 17 N/mm) and the dorsal calcaneocuboid ligament (55 +/- 14 N/mm) were comparable to the dorsal part of the SL ligament (61 +/- 6 N/mm). All the other ligaments had values that were higher than the dorsal part of the SL ligament. The strongest ligament appeared to be the medial dorsal cuneonavicular ligament (479 +/- 65 N), which had a stiffness value of 127 +/- 19 N/mm. Although the third dorsal tarsometatarsal ligament and the dorsal calcaneocuboid ligament are biomechanically most similar to the dorsal part of the SLIL, at present it is unclear how strength and stiffness values of ligaments are sustained following transplantation. From this selection of tarsal ligaments, the medial dorsal cuneonavicular ligament is the strongest ligament and it is therefore concluded that this ligament is the most suitable ligament to be used as an autograft for reconstruction of the SLIL.

Biomechanical Phenomena↗
PubMed1998

Sensate osteocutaneous fibula flap: anatomic study of the innervation pattern of the skin flap.

BACKGROUND: For oromandibular reconstructions, an osteocutaneous fibula flap provides sufficient bone and pliable skin. Sensory reinnervation could possibly prevent problems in mastication and deglutition. METHODS: In this anatomic study, 33 cadaver limbs were microsurgical dissected. We investigated the lateral sural cutaneous nerve (LSCN), which supplies sensation to the skin of the lateral lower leg, in relation to the fibula skin flap. The fibula is vascularized by the peroneal vessels via the posterior intermuscular septum. Therefore, the posterior septum determines the center line of the flap design. RESULTS: The LSCN runs in 74% of the dissections posterior to the posterior septum, whereas an anterior branch was seen in 26%. In 54% of the dissections, the distance to the posterior septum was within 3 cm from the septum, whereas in 86%, the distance was found to be within 4 cm. CONCLUSION: The skin flap should be designed more posteriorly to achieve maximal reinnervation.

Cadaver↗
PubMed1998

Primary skin closure of a large groin defect after inguinal lymphadenectomy for penile cancer using a skin stretching device.

PURPOSE: We describe a method of primary closure of a large skin defect. MATERIALS AND METHODS: A 44-year-old man was treated for penile cancer. After left inguinal lymphadenectomy a large skin defect in the groin remained that could not be closed primarily. Allowing skin to stretch beyond its inherent extensibility with a skin stretching system (Sure-Closure) the wound edges were closed without tension. RESULTS: Primary closure of a large skin defect was possible after cyclic stretching and relaxation of the skin with a skin stretching device. CONCLUSIONS: Large skin defects can be closed primarily using a skin stretching device. The primary advantage of the procedure are its simplicity and avoidance of the need for more complicated reconstructive surgery.

Adult↗
PubMed1998

Carpal boss: destabilization of the third carpometacarpal joint after a wedge excision.

In a standard carpal boss procedure, the dorsal ligament of the involved carpometacarpal joint is cut in the process of performing a wedge excision. We studied the effect of such a dorsal ligament sectioning on the joint between the capitate and middle metacarpal bone in ten fresh-frozen wrist specimens. The passive range of motion of this joint was measured with the joint loaded into flexion and extension and in the unloaded neutral position. After the dorsal ligament of the carpometacarpal joint was cut, simulating a dorsal wedge excision, the passive range of motion was measured again. Analysis indicated that this simulated wedge excision approximately doubled the passive range of motion of the carpometacarpal joint. This study shows that such a procedure disturbs the normal anatomy and creates instability of the involved joint.

Cadaver↗
PubMed1997

Rupture of a flexor pollicis longus tendon in Scheie's syndrome. Case report.

We describe a case of Scheie's syndrome with a closed rupture of the flexor pollicis longus tendon, probably caused by a combination of extrinsic and intrinsic tendon changes. Early detection of carpal tunnel syndrome in all patients who have some form of mucopolysaccharidosis in which this is a universal occurrence (such as Scheie's syndrome), is recommended. Release of the carpal tunnel prevents long term complications, as described in this case report.

Adult↗
PubMed1996

Activity of the extrinsic finger flexors during mobilization in the Kleinert splint.

This study investigated the activity of the extrinsic finger flexor muscles during active extension in the Kleinert splint. Electromyographic data on the activity of the profundus and superficialis flexor muscles in 10 healthy subjects were recorded with use of fine needle electrodes. The subjects exercised in the original Kleinert splint as well as in several modifications of the splint, which varied with respect to (1) wrist position, (2) position in which extension of the metacarpophalangeal joint was blocked, (3) number of fingers dynamically splinted, (4) nature of the spring mechanism, (5) amount of resistance, and (6) use of a palmar pulley. Persistent flexor muscle activity during active extension was observed in the majority of subjects. This coactivity was more often observed for the superficialis muscle than for the profundus muscle. The least amount of coactivity was found when extension was least resisted. This study does not support the concept that the flexor muscles relax during resisted extension in the Kleinert splint.

Electromyography↗