Monocular and binocular reading performance in children with microstrabismic amblyopia.

AIM: To evaluate if functionally relevant deficits in reading performance exist in children with essential microstrabismic amblyopia by comparing the monocular and binocular reading performance with the reading performance of normal sighted children with full visual acuity in both eyes. METHODS: The reading performance of 40 children (mean age 11.6 (SD 1.4) years) was evaluated monocularly and binocularly in randomised order, using standardised reading charts for the simultaneous determination of reading acuity and speed. 20 of the tested children were under treatment for unilateral microstrabismic amblyopia (visual acuity in the amblyopic eyes: logMAR 0.19 (0.15); fellow eyes -0.1 (0.07)); the others were normal sighted controls (visual acuity in the right eyes -0.04 (0.15); left eyes -0.08 (0.07)). RESULTS: In respect of the binocular maximum reading speed (MRS), significant differences were found between the children with microstrabismic amblyopia and the normal controls (p = 0.03): whereas the controls achieved a binocular MRS of 200.4 (11) wpm (words per minute), the children with unilateral amblyopia achieved only a binocular MRS of 172.9 (43.9) wpm. No significant differences between the two groups were found in respect of the binocular logMAR visual acuity and reading acuity (p>0.05). For the monocular reading performance, significant impairment was found in the amblyopic eyes, whereas no significant differences were found between the sound fellow eyes of the amblyopic children and the control group. CONCLUSION: In binocular MRS, significant differences could be found between children with microstrabismic amblyopia and normal controls. This result indicates the presence of a functionally relevant reading impairment, even though the binocular visual acuity and reading acuity were both comparable with the control group.

Evaluating reading acuity and speed in children with microstrabismic amblyopia using a standardized reading chart system.

BACKGROUND: To examine if standardized reading charts with highly comparable test items can be used for evaluating impairments in the monocular reading performance of children with microstrabismic amblyopia characterized by a small angle of squint with less than 5 degrees. METHODS: The reading performance of 22 children (mean age: 11.7+/-1.6 years) with unilateral microstrabismic amblyopia was evaluated monocularly in both eyes, using standardized reading charts for the simultaneous determination of reading acuity and speed. The print sizes of the highly comparable sentence optotypes were logarithmically graded, providing constant geometric proportions for all testing distances in order to control contour interaction. All children were under continuous amblyopia therapy. RESULTS: In the amblyopic eyes, reading acuity and maximum reading speed were significantly impaired when compared to the sound fellow eyes (P<0.001). In respect of the maximum reading speed, a mean inter-ocular difference of 33+/-19 words per minute was found, revealing functionally relevant deficits in monocular reading performance. The amblyopic eyes achieved only a significantly reduced reading acuity (mean inter-ocular difference: LogRAD 0.5+/-0.24; P<0.001). In eight children, the amblyopic eyes achieved a best-corrected visual acuity of LogMAR 0.0 or better: in respect of the visual acuity, there was no significant inter-ocular difference, but reading acuity and maximum reading speed were significantly impaired when compared to the fellow eyes. CONCLUSIONS: Microstrabismic amblyopia was associated with significant impairment of reading acuity and speed in treated amblyopes, even in those with no persistent acuity deficit. To improve treatment addressing these functional deficits, reading performance should be monitored over time using standardized reading tests, which provide essential information about functionally relevant reading impairments.

[Isolated fractures of the orbital floor]. / Isolierte Orbitabodenfrakturen. Korrelation von CT-Vermessungsdaten und ophthalmologischen Daten.

BACKGROUND: The goal of this retrospective study was quantitative calculation of area and volume of isolated orbital floor fractures from computed tomography (CT) and correlation of these data with post-traumatic ophthalmologic findings. PATIENTS AND METHODS: A total of 76 patients with isolated orbital floor fractures were evaluated radiologically and clinically. CT scanning was performed in coronal sections (1.5-mm to 3.0-mm slice thickness) with contiguous table feed. Orbital floor and fracture area as well as volume of displaced tissue were measured and calculated from the CT dataset. The relation of quantitative CT data to ophthalmologic findings (motility, diplopia, and globe position) was assessed statistically. RESULTS: Calculation of the CT dataset revealed a mean orbital floor area of 6.33+/-1.05 cm(2), a mean fracture area of 2.60+/-1.14 cm(2), and a mean volume of displaced tissue of 1.16+/-0.80 cm(3). Volume of displaced tissue correlated significantly with ophthalmologic findings (p< or =0.01). Fracture area correlated significantly with globe position (p< or =0.01) and was less associated with diplopia and motility disturbances (p<0.10). CONCLUSION: Efficient evaluation of two-dimensional CT data enables quantitative assessment of orbital floor fractures. Position and function of the globe are mainly affected by the volume of displaced periorbital tissue.

Follow-up study of treatment of orbital floor fractures: relation of clinical data and software-based CT-analysis.

This retrospective study quantifies isolated orbital floor fractures using software-based CT-analysis and compares the clinical outcome across surgical and non-surgical treatment groups. Depending on the surgeon's interpretation of the clinical and radiological appearance, 10 fractures were treated non-surgically and 20 fractures surgically, either with antral balloon catheter alone or in combination with an orbital implant. Ophthalmologic findings were evaluated until 12 weeks after injury. Fracture area, and volume of displaced tissue (VDT) were assessed by software-based CT-analysis. VDT was marginally significantly smaller in non-surgically than in surgically-treated patients (P=0.08). Ophthalmologic findings improved in all groups during follow-up and no statistical difference was found between the groups. Diplopia remained moderate in three patients with balloon catheter alone, and minimal in four patients in both surgical groups. In one patient with non-surgical treatment, diplopia remained minimal after 12 weeks. Although CT-analysis revealed no significant difference between both surgical groups, patients treated with balloon catheter alone presented more diplopia after 12 weeks. Using balloon catheters for fracture repair a combined approach should be performed when large fractures involve the orbital floor to achieve sufficient reduction of orbital content and placement of an orbital implant. Software-based CT-analysis is helpful for objective interpretation in managing of orbital fractures.

Orbital floor reconstruction with an alloplastic resorbable polydioxanone sheet.

The orbital floor is frequently reconstructed after blow-out fractures or midface fractures to avoid a relapse of the repositioned orbital tissue and to prevent enophthalmos. A total of 31 patients underwent reconstruction of internal orbital wall fractures with a resorbable 0.25 mm or 0.5 mm-thick polydioxanone implant (PDS). Skeletal and functional outcome was evaluated retrospectively with regard to fracture size. Fracture size was graded as small, moderate or large by CT scans and operating records. Two of the 25 patients with small or moderate defects showed an enophthalmos of 2-3 mm. Five of the six patients with large defects or two orbital wall fractures had enophthalmos. The scar that formed after implant resorption was to weak to provide adequate support of the globe or to compensate the enlarged orbital volume. Endoscopic follow-up examination of 12 patients showed yielding of the scar in the orbital floor already in moderate defects. Eight patients had diplopia in extreme gaze and two had significant diplopia. Blow-out and midfacial fractures with small to moderate defects in the orbital floor (up to a size of 2.5 cm2) can be reconstructed by polydioxanone sheet to avoid enophthalmos. Polydioxanone implants should only be used in cases without massive orbital fat herniation. The scar formed after implant resorption may influence functional outcome.

Experience with indium-111 and yttrium-90-labeled somatostatin analogs.

The high level expression of somatostatin receptors (SSTR) on various tumor cells has provided the molecular basis for successful use of radiolabeled octreotide / lanreotide analogs as tumor tracers in nuclear medicine. Other (nontumoral) potential indications for SSTR scintigraphy are based on an increased lymphocyte binding at sites of inflammatory or immunologic diseases such as thyroid-associated ophthalmology. The vast majority of human tumors seem to over-express the one or the other of five distinct hSSTR subtype receptors. Whereas neuroendocrine tumors frequently overexpress hSSTR2, intestinal adenocarcinomas seem to overexpress more often hSSTR3 or hSSTR4, or both of these hSSTR. In contrast to In-DTPA-DPhe(1)-octreotide (OctreoScan(R)) which binds to hSSTR2 and 5 with high affinity (Kd 0.1-5 nM), to hSSTR3 with moderate affinity (K(d) 10-100 nM) and does not bind to hSSTR1 and hSSTR4, (111)In / (90)Y-DOTA-lanreotide was found to bind to hSSTR2, 3, 4, and 5 with high affinity, and to hSSTR1 with lower affinity (K(d) 200 nM). Based on its unique hSSTR binding profile, (111)In-DOTA-lanreotide was suggested to be a potential radioligand for tumor diagnosis, and (90)Y-DOTA-lanreotide suitable for receptor-mediated radionuclide therapy. As opposed to (111)In-DTPA-DPhe(1)-octreotide and (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide, discrepancies in the scintigraphic results were seen in about one third of (neuroendocrine) tumor patients concerning both the tumor uptake as well as detection of tumor lesions. On a molecular level, these discrepancies seem to be based on a "higherrdquuo; high-affinity binding of (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide to hSSTR2 (K(d) 0.1-1 nM). Other somatostatin analogs with divergent affinity to the five known hSSTR subtype receptors have also found their way into the clinics, such as (99m)Tc-depreotide (NeoSpect(R); NeoTect(R)). Most of the imaging results are reported for neuroendocrine tumors (octreotide analogs) or nonsmall cell lung cancer ((99m)Tc-depreotide), indicating high diagnostic cabability of this type of receptor tracers. Consequently to their use as receptor imaging agents, hSSTR recognizing radioligands have also been implemented for experimental receptor-targeted radionuclide therapy. Beneficial results were reported for high-dose treatment with (111)In-DTPA-DPhe(1)-octreotide, based on the emission of Auger electrons. The Phase IIa study "MAURITIUS" (Multicenter Analysis of a Universal Receptor Imaging and Treatment Initiative, a eUropean Study) showed in progressive cancer patients (therapy entry criteria) with a calculated tumor dose > 10 Gy / GBq (90)Y-DOTA-lanreotide, the proof-of-principle for treating tumor patients with peptide receptor imaging agents. In the "MAURITIUS" study, cummulative treatment doses up to 200 mCi (90)Y-DOTA-lanreotide were given as short-term infusion. Overall treatment results in 70 patients indicated stable tumor disease in 35% of patients and regressive tumor disease in 10% of tumor patients with different tumor entities expressing hSSTR. No acute or chronic severe hematological toxicity, change in renal or liver function parameters due to (90)Y-DOTA-lanreotide treatment, were reported. (90)Y-DOTA-DPhe(1)-Tyr(3)-octreotide may show a higher tumor uptake in neuroendocrine tumor lesions and may therefore be superior for treatment in patients with neuroendocrine tumors. However, there is only limited excess to long-term and survival data at present. Potential indications for (90Y-DOTA-lanreotide are radioiodine-negative thyroid cancer, hepatocellular cancer and lung cancer. Besides newer approaches and recent developments of 188)Re-labeled radioligands, no clinical results on the treatment response are yet available. In conclusion, several radioligands have been implemented on the basis of peptide receptor recognition throughout the last decade. A plentitude of preclinical data and clinical studies confirm their potential use in diagnosis as well as "proof-of-principle" for therapy of cancer patients. However, an optimal radiopeptide formulatioents. However, an optimal radiopeptide formulation does not yet exist for receptor-targeted radionuclide therapy. Ongoing developments may result in peptides more suitable for this kind of receptor-targeted radionuclide therapy.

Morphometric and functional results after CO(2) laser welding of nerve coaptations.

BACKGROUND AND OBJECTIVE: Several reports describe nerve coaptations by laser welding in combination with stay sutures and bonding material. This study was undertaken to obtain functional and morphologic information by using a nerve coaptation technique by epineurial CO(2) laser welding only. STUDY DESIGN/MATERIALS AND METHODS: The sciatic nerves of 24 rats were transected and epineurially coapted with the CO(2) laser at 60 mW or with microsutures as a control. Walking track analysis were carried out to evaluate the functional recovery, and the nerves were harvested for histology after 6 months of regeneration. RESULTS: None of the 24 nerves showed dehiscence of the coaptations, and all showed good nerve fiber regeneration. Better results were obtained for the functional evaluation of the sciatic function index (P < 0.02) and the toe spread index (P < 0.04) from the laser nerve coaptations. Likewise, the morphologic evaluations of the fiber density (P < 0.04) and area fraction (P < 0.002) were better in the laser group. CONCLUSION: CO(2) laser welded nerve coaptations are as successful as their sutured counterparts and may become a promising alternative in clinical practice.

External oblique abdominal muscle: a new look on its blood supply and innervation.

Numerous reports have discussed the use of the external oblique abdominal muscle as a pedicled or a free flap for defect coverage. A detailed description of the supplying vessels and nerves is a prerequisite for successful tissue transfer but so far is not available in the literature. A study of the arteries and nerves supplying the external oblique abdominal muscle was carried out in 42 cadavers after injection of a mixture of latex and bariumsulfate. In seven fresh cadavers the motor branches were identified with the Karnovsky technique. Three different groups of arteries were identified as the nurturing vessels. The cranial part of the muscle is supplied by two branches of the intercostal arteries. While the lateral branches run on the outer surface of the muscle together with the nerves, the anterior branches enter the muscle from its inner surface. The caudal part of the muscle derives its main blood supply from one or two branches of the deep circumflex iliac artery (94.7%) or the iliolumbar artery (5.3%). The external oblique abdominal muscle is innervated by motor branches of the lateral cutaneous branches of the anterior spinal nerves in a segmental pattern. With the exception of the subcostal nerve the motor branches enter the outer surface of the muscle digitation arising from the rib above. The results show that the cranial half of the external oblique abdominal muscle has a strictly segmental blood and nerve supply while the caudal half of the muscle derives its main blood supply from one artery but still shows a segmental innervation.

[Nerve coaptation using CO2 milliwatt laser]. / Nervenkoaptation mit dem CO2-Laser im Milliwattbereich.

The technique of laser tissue welding with a low-output CO2 laser has become popular due to the minimal amount of nerve tissue damage caused. The purpose of this study was to ascertain the efficacy of nerve coaptation by laser tissue welding in comparison to micro-sutures. In a first series of 15 rats, peripheral nerves were transsected. 24 nerves were coaptated by laser welding (LW) with different parameters in order to evaluate the optimal laser settings. For comparison, six nerves were coapted (NS) with four 10/0 nylon sutures. Finally, the nerves were removed and the tensile strength of the different coaptations determined. The best results of the laser welds were obtained at laser settings of 40 to 60 mW in the continuous mode resulting in a tensile strength of 9.5 +/- 2.2 g. The tensile strength was 39.3 +/- 7.3 g for the sutured coaptation. In a second series, one sciatic nerve was coapted in thirteen rats by laser welding (LW) (60 mW, cont. mode) and in eleven rats using four 10/0 nylon sutures (NS). After six months, the Sciatic Function Index (SFI) was evaluated and the nerves were harvested for histological examination of transverse and longitudinal sections. All animals showed good regeneration and none of the 24 nerve coaptations showed dehiscence. The SFI was for the NS-group -94 +/- 23 and for the LW-group -77 +/- 20. The mean number of myelinated nerve fibres (NS 10,170 +/- 2512 vs. LW 11,902 +/- 1649) and the fibre diameter (NS 4.30 +/- 0.14 um vs. LW 4.02 +/- 0.59 microns) of the nerves distal to the coaptation were similar in both groups and showed no statistical difference. We conclude that nerve coaptation by CO2-laser welds are as successful as the 10/0 nylon sutures in the animal model. Improvements of welding techniques may in the future reduce nerve damage even further and so yield even better functional results.

Human facial muscles: dimensions, motor endplate distribution, and presence of muscle fibers with multiple motor endplates.

BACKGROUND: Extrafusal muscle fibers of human striated skeletal muscles are known to have a uniform innervation pattern. Motor endplates (MEP) of the "en plaque" type are located near the center of muscle fibers and distributed within the muscles in a narrow band. The aim of this study was to evaluate the innervation pattern of human facial muscles and compare it with that of skeletal muscles. METHODS: Ten facial muscles from 11 human cadavers were dissected, the nerve entrance points located, and the dimensions measured. All muscles were stained in toto for MEPs using Acetylcholinesterase (AChE) and examined under the microscope to determine their location. Single muscle fibers were teased to evaluate the stained MEPs. RESULTS: The length of the different facial muscles varied from 29 to 65 mm, which correlated to the length of the corresponding muscle fibers. MEP zones were found on the muscles in the immediate vicinity of the nerves' entrance points and located eccentrically. Numbers and locations varied from muscle to muscle. Three MEP zone distribution patterns were differentiated: numerous small MEP zones were evenly spread over the muscle, a predominant MEP zone and two to three small zones were spread at random, and two to four MEP zones of equal size were randomly scattered. One MEP of the "en plaque" type was found in 73.8% of the muscle fibers and two to five MEPs were found in 26.2%. The distances between the multiple MEPs on one muscle fiber varied from 10 to 500 microm. CONCLUSIONS: This study suggests that facial muscles differ from skeletal muscles regarding distribution and number of MEPs. The eccentric location of MEP zones and multiple MEPs suggests there is an independent mechanism of neural regulation in the facial muscle system.

The external oblique muscle free flap.

To date, the external oblique muscle has been considered to have a purely segmental vascular supply and therefore has been used surgically only as a pedicled flap. To better define the vascular anatomy and nerve supply of the muscle, we performed arterial injection studies and dissected the nerves that entered the muscle in 35 human cadavers. We found that in addition to the segmental arteries, one or two large branches of the deep circumflex iliac artery contributed significantly to the blood supply of the external oblique muscle in 33 of the 35 cadavers. We also found that the lateral cutaneous branches of the intercostal nerves entered and supplied the muscle near its origin from the rib in a strictly segmental pattern. These anatomic findings enabled us to transplant the external oblique muscle successfully as a free flap based on the deep circumflex iliac vessels in six patients. The muscle flap is thin, pliable, and can be combined with an iliac bone or an abdominal skin transplant. Its vascular pedicle is long (mean 12 cm) and of adequate diameter for microvascular repair. The donor scar of the flap is inconspicuously situated along the inguinal ligament and the iliac crest. Finally, since the muscle has a multiple nerve supply, it has the potential to provide several functional units at the recipient site when transplanted as a functional free flap.

Effect of the CO2 milliwatt laser on neuroma formation in rats.

BACKGROUND AND OBJECTIVE: The purpose of this study was to determine whether the milliwatt laser can suppress neuroma formation at the end of a divided nerve. STUDY DESIGN/MATERIALS AND METHODS: The peripheral nerves of eight rats were transected with microscissors and the cross-sectional area of their proximal ends was irradiated using the CO2 milliwatt laser. The power ranges used were similar to those applied to weld neural tissue. RESULTS: None of the eight irradiated nerve ends formed a neuromatous bulb and only one of them regenerated into the surrounding tissues. Histologically, these nerve ends did not show the disorganized picture of classic neuromas. On morphometric measurements, they contained less connective tissue than the control nerve ends (P < 0.001) and their nerve fibers were larger in diameter (P < 0.001) and better myelinated (P < 0.001). CONCLUSION: These findings in rats show that the CO2 milliwatt laser has the ability to suppress neuroma formation at the end of a divided nerve.

Clinical and electroneurographic evaluation of sensory/motor-differentiated nerve repair in the hand.

In 17 patients acetylcholinesterase activity was used to differentiate between sensory and motor fascicles in median and ulnar nerve repair of the hand. Eleven patients received follow-up evaluation 1 to 11 years after surgery, and at that time clinical and electroneurographic examinations were performed to evaluate the techniques. Clinical examination showed that four patients had regained on average 71.9% of hand function after median nerve repair, one patient had regained 83.6% of hand function after ulnar nerve repair, four patients had regained on average 53.3% of hand function after median and ulnar nerve repair, and two patients had regained on average 43.5% of hand function after median and partial ulnar nerve repair. The contribution of the ulnar nerve to reinnervation of the thenar muscles was 68.5%, whereas the median nerve did not contribute to reinnervation of the hypothenar muscles. Distal latencies for the median nerve showed a delay of 36% of the upper limit of normal value, and those for the ulnar nerve revealed a delay of 21.5%. This study demonstrated that sensory/motor-differentiated nerve repair of the median and ulnar nerves is possible and can be proven electroneurographically.

Peripheral nerve repair in the hand with and without motor sensory differentiation.

To investigate the value of motor sensory differentiated nerve repair, we examined a group of 9 patients with motor sensory differentiated nerve repair and a group of 13 patients without motor sensory differentiated nerve repair. The clinical and electroneurographic findings were compared. For the clinical examination, Millesi's scoring system was used. The hand function after motor sensory differentiated median nerve repair was 72% +/- 16% compared with 57% +/- 14% without motor sensory differentiation. The hand function after motor sensory differentiated median and ulnar nerve repair was 53% +/- 12% compared with 43% +/- 24% without motor sensory differentiation. After ulnar nerve repair the achieved values for hand function were high even without motor sensory differentiation. Our results indicate that intraoperative motor sensory differentiation of injured nerves is helpful to reestablish particularly the sensory function in median nerve injuries.

Clinical application of motorsensory differentiated nerve repair.

Since 1979 acetylcholinesterase has been used in clinical practice for motor sensory differentiation. It was first used for median and ulnar nerve injuries at the wrist. Recently the application was extended to secondary nerve repair, including plexus reconstruction. The aim of this study was to present, for the first time, clinical results of motor sensory differentiated median and ulnar nerve repair and to show the advantage of this method in secondary repair. We compared a group of nine patients with motor sensory differentiated median and ulnar nerve repair with a group of 13 patients without motor sensory differentiation. Sensibility testing, strength measurements, and anatomical examinations were performed. The hand function was expressed in percentage values. Compound muscle action potentials and sensory antidromic conduction velocities were measured electroneurographically. Sensibility recovery was significantly better after motor sensory differentiated median nerve repair (P < 0.05). In secondary nerve repair acetylcholinesterase was used additionally for evaluating the level of resection of the proximal stump. The time required for perioperative histochemical differentiation has now been reduced to 2 hr.

Histochemical mapping and fiber size analysis of mimic muscles.

Fourteen functionally relevant mimic muscles of nine human bodies were analyzed with respect to their muscle fiber sizes and their histochemical fiber type composition. In cryostat sections stained for actomyosin ATPase, type 1 and type 2 fibers were evaluated separately by means of computer-assisted image analysis. The fiber diameters varied between 20.24 and 41.45 microns. According to the proportions of the fiber types, the mimic muscles could be classified into three groups: (1) phasic muscles, with 14 to 15 percent type 1 fibers, (2) intermediate muscles, with 28 to 37 percent type 1 fibers, and (3) tonic muscles, containing 41 to 67 percent type 1 fibers. It is concluded that one has to consider this diversity of mimic muscles when planning the surgical reconstruction of facial paralysis.

Histochemical characteristics of human mimic muscles.

Eight different mimic muscles of 13 human cadavers (7 male, 6 female) were studied by histochemical techniques. In sections stained for myosin ATPase the composition of fibre types was quantitatively evaluated by computer-assisted image analysis. The data were compared to those of 2 muscles in the lower limb of the same individuals. According to the percentage of the type I muscle fibres 3 groups of mimic muscles were distinguished: (1) the orbicularis oculi muscle (15%), (2) the major zygomatic, levator labii superioris, levator anguli oris, depressor anguli oris muscles and platysma (27-38%), and (3) the occipitofrontal and buccinator muscles (57-77%). For comparison, the gracilis and rectus femoris muscles were built up by 36% and 48% of type I fibres. The average diameters of fibres in mimic muscles were significantly less than in the 2 limb muscles. Differences in muscle fibre size between male and female specimens were not significant. The relevance of morphological characteristics of mimic muscles for facial expression and reconstructive surgery is discussed.