20G Group Research Articles

Pars plana vitrectomy for the repair of primary, inferior rhegmatogenous retinal detachment associated to inferior breaks. A comparison of a 25-gauge versus a 20-gauge system

BackgroundTo compare anatomical, functional outcomes and complications of high-speed 25-gauge (G) pars plana vitrectomy (PPV) versus 20-G PPV for the management of primary inferior rhegmatogenous retinal detachment (RRD) associated to inferior breaks/holes.MethodsEighty-five eyes from 85 patients with a minimum follow-up of 3 months were retrospectively evaluated. Forty-one patients underwent 25-G and 44 patients underwent 20-G PPV. All patients underwent PPV with fluid-air exchange, sulfur hexafluoride (SF6) 20 % gas tamponade and laser or cryo retinopexy.ResultsThe mean follow-up interval was 6.51(±2.32) and 6.63 (±2.58) months in the 25-G and 20-G groups respectively. Single-operation success rate was 92.7 % for the 25-G group and 81.8 % for the 20-G group (P = 0.24). Post-operative hypotony was observed in no case. Redetachment occurred in 3 eyes operated on with 25-G and in 8 eyes operated on with 20-G system. All retinas were attached at final follow-up. Logarithm of the minimum angle of resolution visual acuity significantly improved from 0.69 ± 0.76 to 0.33 ± 0.37 in the 25-G and from 0.47 ± 0.59 to 0.21 ± 0.28 in the 20-G group (P = 0.0007 and P < 0.0001 respectively).ConclusionsHigh-speed PPV and SF6 gas tamponade using either 25-G or 20-G PPV system, yields similar single operation anatomical success rates for the repair of uncomplicated, primary inferior RRDs associated to inferior breaks.

SUTURELESS 23-GAUGE VERSUS 20-GAUGE VITRECTOMY WITH SILICONE OIL INJECTION IN RHEGMATOGENOUS RETINAL DETACHMENT

To report the efficacy of 23-gauge (G) pars plana vitrectomy with silicone oil injection in rhegmatogenous retinal detachment. Retrospective chart review of consecutive patients with retinal detachment who underwent pars plana vitrectomy by one of two surgeons using distinct and consistent methods. All patients undergoing 23-G pars plana vitrectomy did not have scleral buckling, whereas all patients undergoing surgery by 20-G pars plana vitrectomy had additional 240-band encircling scleral buckle. All patients received silicone oil tamponade. Patients with proliferative vitreoretinopathy Grade D, previous retinal detachment surgery, and penetrating eye injury were excluded. The main outcome measure was the final anatomical reattachment rate. The secondary outcome measures were the improvement in visual acuity and recurrence rate of retinal detachment after primary surgery. Eighteen patients in the 23-G group and 21 patients in the 20-G group were analyzed. The mean age of the patients was 48.05 ± 10.37 years and 42.57 ± 17.84 years in the 23-G and 20-G groups, respectively. The mean follow-up duration was 5.9 months (range, 2-12 months) and 6.2 months (range, 4-9 months) in the 23-G and 20-G groups, respectively. The primary reattachment rate was 83.3% (95% confidence interval, 66.11%-100%) in the 23-G group and 86.8% (95% confidence interval, 67.81%-100%); P = 1.00) in 20-G group. The mean preoperative logarithm of the minimum angle of resolution visual acuity was 1.30 ± 0.57 (Snellen equivalent 20/400) in the 23-G group and 1.27 ± 0.70 (Snellen equivalent 20/400) in the 20-G group (P = 0.80). The mean logarithm of the minimum angle of resolution visual acuity at 1 month after the surgery was 0.66 ± 0.25 (Snellen equivalent 20/100) in the 23-G group and 0.77 ± 0.50 (Snellen equivalent 20/120; P = 0.46) in the 20-G group. The visual acuity at the last visit was 0.80 ± 0.52 (20/125) versus 0.65 ± 0.44 (20/100) in the 23-G and 20-G, respectively (P = 0.32). Silicone oil injection with 23-G system is possible and is associated with favorable anatomical success in cases of rhegmatogenous retinal detachment.

Minimal Refractive Change Induced by Sutureless 23- and 25-Gauge Pars Plana Vitrectomy

This study reports the induced refractive error after 23- and 25-gauge (G) pars plana vitrectomy (PPV). In this non-randomized retrospective case series, refractive status was assessed with an autokeratorefractometer 1 week or more before and 6 months after surgery. Patients who had suture placement to close the sclerotomies were excluded from the study. Among the 50 patients (50 eyes), the mean age was 63 years (range: 42 to 76 years) and 57% were female. Thirty eyes underwent 23-G PPV and 20 eyes underwent 25-G PPV. The mean refractive change was +0.50 diopters (D) sphere, +0.25 D cylinders and the mean axis of cylinder change was 6° for the 23-G group; the mean refractive change was +0.12 D sphere, +0.12 D cylinders and the mean axis of cylinder change was 17° for the 25-G group. Following sutureless small-gauge vitrectomy, there were mild and minimally significant refractive changes in the 23-G and 25-G groups from baseline.

Influence of vitrectomy for corneal thickness in diaebetic retinopathy eyes with Pentacam

Background The research of corneal thickness after pars plana vitrectomy in DM patient plays an important role not only theoretically but clinically. Objective Present study was to evaluate the change in corneal thickness after pars plana vitrectomy. Methods A prospective coherent study was designed.Seventy-five eyes of 70 consecutive diabetic retinopathy(DR) patients were collected in Tianjin Medical University Eye Center.Pentacam was used to assess the central and periphery corneal thickness by the same investigator preoperatively and 7 days,1 and 3 months postoperatively,respectively.The thickness values from five corneal zone were obtained,including cornea vertex,the thinnest point of the cornea,periphery cornea near the scleral incision of 4 mm away to vertex of cornea on vertical and 240°,120°,60° meridian ( right eye) or 300°,120°,60° meidian ( left eye ).These results were compared and analyzed with ANOVA of repeated measurement data.Subgroup analysis was performed to evaluate the influence of different corneal positions,the use of conventional 20g or 23g transconjunctival sutureless vitrectomy(TSV) groups,surgery duration,gas or fluid endotamponde on corneal thickness.This study was approved by Ethic Committee of this hospital.Written informed consent was obtained from the subjects before any relative medical procedure. Results The mean corneal thickness was ( 639.9 ± 103.1 ),( 689.5 ± 119.3 ),( 666.5 ±113.7),( 650.8 ± 108.6 ) μm before operation,postperative 7 days,1 and 3 months respectively.As covariates appearing in the model,the corneal thickness change rates were revised as the parameters as following: diabeitc duration =13.0 and age =57.2.The revised corneal thickness was significant different among various time points( F=210.928,P=0.000) and different corneal zones(F=24.843,P=0.000) with the size order in turn P4＞P3＞P1＞P2＞P5.The corneal thickness change rates were less in 23g TSV group compared with conventional 20-g group (F =53.843,P =0.000) and BSS tamponade group compared with gas tamponade group ( F =5.288,P =0.022).But no significant difference was found in the revised corneal thickness among surgery duration ＜ 1 hour group,1-2 hour group and ＞2 hour group( F=1.233,P =0.293). Conclusions Vitrectomy is a safe procedure on the ground of cornea,but TSV and fluid endotamponade appear to be more beneficial to the protection of cornea.Pentacam could offer the reliable data in not only central cornea but also periphery cornea. Key words: Corneal thickness/center, periphery; Transconjunctival sutureless vitrectomy; Diabetic retinopathy

Twenty five-gauge sutureless vitrectomy versus 20-gauge vitrectomy in epiretinal membrane surgery

To compare visual outcomes, intraoperative and postoperative complications of 25-gauge transconjunctival sutureless vitrectomy (25-G TSV) versus conventional 20-gauge vitrectomy in epiretinal membrane (ERM) surgery. A retrospective comparative study was conducted on 200 eyes with idiopathic ERM who underwent either primary 20-gauge vitrectomy (n=95) or 25-G TSV (n=105) with 6 months follow up. The following parameters were collected and compared: age, gender, best corrected visual acuity (BCVA), intraocular pressure (IOP), postoperative anterior chamber inflammation, intraoperative and postoperative complications. Twenty-five gauge group achieved a significantly better vision at the 1(st) postoperative month (p=0.008) and a significantly higher incidence of visual improvement 6 months postoperatively (p=0.04) than 20-gauge group. Intraocular pressure was significantly higher at the 1(st), 3(rd) and 6(th) postoperative months compared with baseline in the 20-G group. However, in the 25-gauge group IOP remained near to the baseline at the same period. Twenty five-gauge group achieved a significantly lower anterior chamber inflammation and a lower incidence of postoperative cystoid macular edema (CME) (p=0.01), hyphema (p=0.000) and after cataract (p=0.000) than 20-gauge group. The 25-gauge sutureless vitrectomy achieves rapid and higher visual improvement, less postoperative inflammation and complications than the 20-gauge vitrectomy in ERM surgery.

25-, 23-, and 20-gauge vitrectomy in epiretinal membrane surgery: a comparative study of 553 cases

To compare the safety and functional outcomes of 25-gauge and 23-gauge (G) micro-incision vitrectomy surgery (MIVS) instrumentation with the standard 20-G vitrectomy system in the treatment of epiretinal membranes (ERM). A retrospective comparative study of 553 consecutive cases with epiretinal membrane who underwent pars plana vitrectomy. Twenty-gauge, 25-gauge and 23-gauge vitrectomy was performed respectively in 347, 91, and 115 eyes. Surgery duration, visual acuity improvement, intraocular pressure variation, intraoperative and postoperative complications were analyzed. The mean surgical time in the 23-G group and in the 25-G group was shorter than in the 20-G group (P < 0.001). Visual improvement was higher 8days postoperatively in the 25-G group than in the 20-G and 23-G groups (P = 0.035), but not at 6weeks postoperatively (P = 0.186). In the 20-G group, the IOP increased significantly on the first day postoperatively (P < 0.001), while in the 23-G group, the IOP decreased on the first day postoperatively (P = 0.073). In the 25-G group, the IOP did not change significantly (P = 0.807). The incidence of complications was not statistically significant between the three groups. Retinal breaks were significantly related to the induction of posterior vitreous detachment, independent of the system gauge. In ERM surgery, 23-G and 25-G (MIVS) systems are as safe and effective as the 20-G system, and significantly reduce surgical time. Although the 25-G system provides an earlier visual improvement, the 23- and 25- gauge systems are comparable, and the selection will depend on the surgeon's preference.

Effects of force magnitude on relapse: An experimental study in rabbits

The aims of this study were to investigate the effects of 2 force levels on the amount of relapse and to determine whether there is a relationship between the rates of tooth movement and relapse. Approximately 20-g (group I) and 60-g (group II) forces were applied to the maxillary central incisors of 25 young adult (14 weeks of age) New Zealand female rabbits. Active tooth movement lasted 20 days. Then, the appliances were removed, and the incisors were released. The distance between the incisors was measured daily from the midlevels of the crowns by using a digital caliper during the active phase of tooth movement for 20 days, and then relapse was measured at the same level for 37 days. Analysis of variance and the Bonferroni multiple range test were used for statistical analyses. After active tooth movement, the mean total opening amounts were 3.98 ± 0.59 mm in group I and 4.82 ± 0.82 mm in group II, and the mean difference was approximately 0.8 mm. A rapid relapse was observed on the initial days in both groups, and its rate decreased with time. Significant relapse was observed in the first 5 and 8 days of the experiment in 20-g and 60-g force groups, respectively. The relapse in group II was significantly greater than in group I only on the first day of experiment. Statistically significant correlations were found between total tooth movement and relapse (R= 0.896, P<0.001). These results showed a close relationship between the amount of relapse and orthodontic force magnitude. Greater relapse occurred during the initial days after appliance removal, and this indicates that retention appliances are needed immediately after the removal of orthodontic appliances.

Comparative study of 23-gauge vitrectomy versus 20-gauge vitrectomy for the treatment of rhegmatogenous retinal detachment

To compare the safety and efficacy of 20- and 23-gauge pars plana vitrectomy (PPV) for the management of primary rhegmatogenous retinal detachment (RD) with proliferative vitreoretinopathy (PVR) grade B or less. This comparative nested case-control study included 35 consecutive 23-gauge transconjunctival PPV cases matched (1:1) with 35 cases of 20-gauge PPV (from a prospective cohort of 1,150 patients) for the baseline visual acuity (VA), axial length, lens and macular status, the location and number of breaks, and PVR grade. All patients had complete PPV, cryotherapy, fluid-gas exchange, and a minimum follow-up of 6months. The exclusion criteria were eyes with previous vitreoretinal surgery, combined vitrectomy and cataract surgery, RD secondary to trauma or macular hole, diabetic retinopathy, aphakic eyes, giant tears, or posteriorly located breaks precluding treatment using transconjunctival cryotherapy. Baseline examination disclosed pseudophakia in 77.1%, high myopia in 11.4%, 2.7 ± 2.2 retinal breaks/eye, attached macula in 37.1%, and PVR grade B in 24.3% of the cases. The mean operative time and intraoperative complication rate (11.4%) were similar in both groups. In the 23-G group, we noted three cases of iatrogenic retinal tears and one case of choroidal detachment secondary to a dislodgment of the infusion line. Suturing the sclerotomy sites or the conjunctiva was required in 5.7 and 51% of the eyes, respectively. The single reattachment rate was similar in both groups, 74.3% in the 20-G group, and 80% in the 23-G group. The final anatomical success rate was 97% in the two groups. Mean preoperative VA of 1.2 ± 0.9 logMAR improved similarly in both groups to 0.4 ± 0.4 at the 6-month visit. A final vision of 20/40 or better was achieved similarly in 62.9% of the eyes in the 20-G group and 60% in the 23-G group. Twenty-three-gauge PPV provides anatomical and visual results similar to the 20-G technique for the management of uncomplicated rhegmatogenous RD.

799 The Diagnostic Accuracy of 22- and 25-Gauge Needles in EUS-FNA of Solid Pancreatic Lesions: A Meta-Analysis

The Diagnostic Accuracy of 22and 25-Gauge Needles in EUSFNA of Solid Pancreatic Lesions: A Meta-Analysis Mohammad Madhoun, Sachin B. Wani, Dayna S. Early, Srinivas Gaddam, Amit Rastogi, William M. Tierney, John T. Maple Internal Medicine/ Digestive Diseases, University of Oklahoma Health Sciences Center, Oklahoma City, OK; Division of Gastroenterology, Washington University School of Medicine, St Louis, MO; Division of Gastroenterology and Hepatology, Veterans Affairs Medical Center and University of Kansas School of Medicine, Kansas City, MO Background: Several studies have assessed the performance characteristics of 22and 25-gauge needles in endoscopic ultrasound with fine needle aspiration (EUS-FNA) of pancreatic mass lesions, but most have failed to demonstrate superiority of either needle. Aim: Use meta-analysis to more robustly define the diagnostic accuracy of EUS-FNA for pancreatic masses using different gauge FNA needles. Methods: Studies were identified by searching ten medical databases including Ovid MEDLINE and the Cochrane Library Database for reports published between 1994 and 2010, using a reproducible search strategy comprised of relevant terms. References from retrieved articles and national meeting abstracts were also manually reviewed. Only studies comparing the overall diagnostic accuracy of 22-g vs 25-g EUS needles that used surgical histology or at least 6 months clinical follow up for a gold standard were included. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. When required, the original investigators were contacted to provide additional data. Pooling was conducted by both fixed-effects and random-effects models; results are presented from the random effects model when heterogeneity was significant. Diagnostic characteristics (sensitivity, specificity, positive and negative likelihood ratios) with 95% confidence interval (CI) were calculated. Results: Six studies (involving 1064 subjects) met the defined inclusion criteria. Of the 1064 patients, 678 subjects were in the 22-g group and 434 subjects were in the 25-g group (both needles were used in 48 patients). The performance characteristics of the two needles are contrasted in the accompanying table. The bivariate generalized linear random-effect model indicated that the 25-g needle is associated with a higher sensitivity (p 0.001) but comparable specificity (p 0.82) to the 22-g needle. The rate of needle malfunction was similar between the 2 groups (p 0.6). The nature of the data reporting did not allow for evaluation of some variables, such as diagnostic accuracy by anatomic sub-sites (e.g. head, body/ tail) and physician ease of use. Conclusions: This meta-analysis suggests 25gauge needle systems are more sensitive than 22-gauge needles for detecting pancreatic malignancy. Potential explanations include fewer bloody specimens, better needle traversal through firm masses, and technically easier access to lesions in the medial aspect of the pancreatic head and uncinate process while using the smaller caliber needle.

FASTER VISUAL RECOVERY AFTER 23-GAUGE VITRECTOMY COMPARED WITH 20-GAUGE VITRECTOMY

To evaluate whether 23-gauge (23 G) pars plana vitrectomy is associated with earlier visual recovery compared with standard 20-gauge (20 G) pars plana vitrectomy. Retrospective chart review of patients who underwent pars plana vitrectomy for various indications was performed. Thirty consecutive eyes in each group of 23-G and 20-G pars plana vitrectomy were analyzed. The mean decimal acuity of each patient was recorded at baseline, Day 1, and Weeks 1 and 6. The visual acuity on postoperative Day 1 and Week 1 was calculated as a proportion of the visual acuity at Week 6. The primary outcome measure was the rate of gain in visual acuity. The secondary outcome measures were intraocular pressure and surgical time. The baseline visual acuity between the two groups was similar. The mean visual acuity on Day 1 (0.05 ± 0.09 20 G versus 0.16 ± 0.18 23 G; Snellen equivalent 20/400 versus 20/125; P = 0.004) and Week 1 (0.12 ± 0.20 20 G versus 0.30 ± 0.27 23 G; Snellen equivalent 20/160 versus 20/63; P = 0.002) was significantly better in the 23-G pars plana vitrectomy group. There was no significant difference in best-corrected Snellen visual acuity at Week 6 between the 2 groups. Eighty-three percent of the mean final visual acuity was attained by Week 1 in the 23-G group compared with only 43% in the 20-G group. Twenty-three gauge pars plana vitrectomy is associated with faster visual recovery compared with 20-G pars plana vitrectomy.

Transconjunctival Sutureless 25-Gauge Versus 20-Gauge Standard Vitrectomy: Correlation Between Corneal Topography and Ultrasound Biomicroscopy Measurements of Sclerotomy Sites

To determine the correlation between corneal shape changes and ultrasound biomicroscopy (UBM) findings at the sclerotomy sites in conventional 20-gauge (G) pars plana vitrectomy (PPV) and 25-G transconjunctival sutureless vitrectomy (TSV) and to compare the effectiveness of the two surgical methods. Prospective, comparative, observational case series. Sixty consecutive eyes (60 patients) undergoing primary 3-port PPV. Thirty eyes (30 patients, group 20-G) were treated with 20-G standard PPV and 30 eyes (30 patients, group 25-G) with 25-G TSV. We compared healing of the sclerotomy sites in the two groups. We determined the correlation between corneal shape changes (surgically induced astigmatism) measured by video keratography and the durations of scleral healing cicatrization by UBM within each group. UBM examination showed that the 20-G sclerotomy sites took about 8 weeks to heal, measured as complete opposition, whereas healing of the 25-G TSV sclerotomy was quite rapid, with complete scleral opposition in about 4 weeks. Corneal topography analysis showed, during the early postoperative period, a surgically induced steepening of the cornea in both groups (20 G, 3.08 +/- 0.56 diopters and 25 G, 0.805 +/- 0.61 diopters, P < 0.001, Mann-Whitney test), which then decreased gradually, recovering to the preoperative level within two months in group 20 G (P > 0.05) and 1 month in group 25 G (P > 0.05). We found a strong statistical correlation between the mean surgically induced keratometric astigmatism and the mean UBM measures of scleral healing (r = 0.99 for group 20 G and r = 0.97 for group 25 G). After PPV, astigmatic changes are especially significant in the early postoperative period in 20-G group; the 25-G TSV system results in faster reduction of surgically induced keratometric astigmatism because of rapid cicatrization of the sclerotomy sites.

Comparison of complications in second trimester amniocentesis performed with 20G, 21G and 22G needles

to compare short- and long-term complications of amniocentesis performed with 20G, 21G, and 22G needles. this observational study included 793 pregnant women who underwent amniocentesis in the Perinatology Department of Cerrahpasa Medical Faculty, Istanbul University, Turkey. The patients were divided into three groups according to the needle size used for the procedure: 20G (Group 1), 21G (Group 2), and 22G (Group 3). The incidences of early and late complications were compared among groups. fetal loss rates did not differ among groups (Group 1=1.57%, Group 2=1.47%, Group 3=1.61%). Rates of vaginal bleeding (1.57%, 1.10%, and 0.81%, respectively), bloody amniotic fluid (2.32%, 6.23%, and 2.67%, respectively) and amniotic fluid leakage (1.57%, 1.10%, and 1.61%, respectively) were also similar among the three groups. short- and long-term complications did not differ among amniocenteses performed with 20G, 21G, and 22G needles.

A pilot randomised controlled trial comparing the post-operative pain experience following vitrectomy with a 20-gauge system and the 25-gauge transconjunctival system

Aims:To compare post-operative pain following 25-gauge (25G) and 20-gauge (20G) vitrectomy in the first week following surgery.Methods:The study was a pilot randomised controlled trial with patients masked to the treatment...

Comparison between 20G and 22G needle for second trimester amniocentesis in terms of technical aspects and short‐term complications

To compare short-term complications of amniocentesis using 20G versus 22G needle. A total of 200 women referred for mid-trimester amniocentesis were randomized to a 20G (Group I, n = 100) or 22G amniocentesis needle (Group II, n = 100). The primary outcome was intrauterine bleeding at needle insertion. The operator reported technical aspects and patient's reactions immediately after the procedure. Women's perception of discomfort 30 min after the procedure and complications after 2 weeks were recorded. Intrauterine bleeding at needle insertion was similar between groups (4/100 vs 8/100). When only transplacental taps were analyzed, bleeding was significantly lower in Group I (4/20 vs 8/14, p = 0.035). Fluid retrieval was faster in Group I (9.6 vs 26.8 sec, p < 0.001). In all, 65% of women in Group I versus 30% in Group II reported discomfort during the procedure, although discomfort 30 min after the procedure and complications within 2 weeks after the procedure were similar in the two groups. Amniocentesis with 20G needle is associated with lower risk of intrauterine bleeding in case of transplacental needle insertion and allows for faster fluid retrieval, as compared with 22G needle. Nevertheless, 20G needle is associated with more immediate discomfort during the procedure.

Visual recovery after vitrectomy for macular hole using 25‐gauge instruments

To determine whether vitrectomy with 25-gauge instruments contributes to better postoperative visual recovery after macular hole (MH) surgery. The medical records for 46 consecutive eyes operated for MH by a single surgeon were retrospectively examined. Vitrectomy had been performed with a 25-gauge instrument in 23 eyes (25-G group) and with a 20-gauge instrument in 23 eyes (20-G group). Postoperative visual acuity (VA) in logMAR (logarithm of the minimum angle of resolution) units after 1 week and 1, 3, 6, 9 and 12 months, operating time, and volume of intraocular irrigating fluid were compared between the two groups. Mean preoperative logMAR VA was 0.72 in the 25-G group and 0.68 in the 20-G group (p = 0.282, unpaired t-test). One week after surgery, VA was significantly better in the 25-G group (0.40 +/- 0.34) than in the 20-G group (0.58 +/- 0.30) (p = 0.020). This significant difference was maintained until 9 months after surgery, but was no longer evident at 12 months (p = 0.182). Operating time was significantly shorter in the 25-G group (56 +/- 16 mins) than in the 20-G group (85 +/- 28 mins) (p = 0.003, unpaired t-test). The volume of intraocular irrigating fluid was significantly less in the 25-G group (244 +/- 72 ml) than in the 20-G group (416 +/- 113 ml) (p < 0.0001). The use of 25-gauge vitrectomy instruments leads to better postoperative visual recovery following surgery for MH during the first 9 months, probably as a result of shorter surgical time and a lower volume of intraocular irrigating fluid.

A reply

We would like to thank Drs Hull and Rucklidge for their interest in our article. Our study found that the ‘pop’ was not always felt when using a 27G spinal needle in the term pregnant woman. The study did not compare the safety of a continuous push technique with that of incremental advancement of the spinal needle and so we cannot conclude that the incremental technique is safer. Given the result of our study, we can, however, suggest that a technique that could minimise the extent of needle penetration into the intrathecal space would, logically, lead to a reduced risk of impingement upon neurological tissue. As the incidence of neurological damage from spinal anaesthesia is fortunately very low, it would not be feasible to perform a study that could prove this. We would point out that it was Professor Reynolds' case series that recently highlighted the risks of causing severe neurological damage with a spinal needle and so we do have evidence that damage is caused using current techniques of spinal needle insertion [1]. Both cadaveric and radiological studies have found that Tuffier's line crosses the body of L4 or the L4/5 disc space in 78.6% of people [2, 3]. One space above Tuffier's line should be L3/4, one below L4/5 and two above, L2/3. In our study the first position attempted was one space above Tuffier's line, which should be L3/4 and the second position for spinal needle insertion was one space below Tuffier's line, which should be L4/5. Any space below this, in our experience, is often unsuccessful, as this would be L5/S1. This is especially true in the hands of cautious trainees who are often lower than they think. As for two spaces above Tuffier's line being out of bounds – one of the main points of our article is that you cannot reliably predict which intervertebral space you are using and that you will frequently be at the cord level, so an incremental advancement technique may be the safer option. L2/3 is an option if levels below have been unsuccessful. We feel that is better to insert a spinal needle using as safe a technique as possible at a higher level, rather than persisting at lower levels, failing, and needing to subject a woman to a general anaesthetic with its attendant risk. The gauge of the spinal needle is a compromise between the incidence of postdural puncture headache (PDPH) and failure to locate the subarachnoid space. In the study quoted by Drs Hull and Rucklidge, use of 25G Whitacre needles caused one severe PDPH necessitating blood patch and three mild cases [4]. There were none in the 27G group. Whilst we accept that the 27G has a higher failure rate, PDPH can be devastating for an otherwise well lady who has to care for a newborn infant. The 27G needle is the standard needle in our unit. In our study of elective patients, adequate spinal anaesthesia was provided within 20 min. The incremental technique added, at most, 1–2 min. No undue discomfort was felt by the women. Whilst we cannot extrapolate our data to the emergency situation, we cannot see any reason for our technique to cause undue delay and concern in terms of time to provide adequate anaesthesia. Again, as in all things medical, an assessment of the balance of risk must be made. For most, if not all, emergency category 2 Caesarean sections, an extra minute would be of no consequence. For a category 1 emergency Caesarean section it is always possible to revert to a continuous push technique, possibly utilising a 25G needle, if a spinal anaesthetic is deemed appropriate for that situation.

Needle diameter in outpatient myelography: rates of adverse effects and current practice trends.

Telephone calls were made to 1251 consecutive patients one day following outpatient myelography. Data were available on 518 patients punctured with 22-gauge (g) (large-diameter) and 465 with 25-g (small-diameter) spinal needles. We surveyed 48 academic and private practice groups regarding needle diameter use in myelography; data were obtained from 34 private practice and 14 academic radiology departments. Patients reported adverse effects including mild and severe headache, back pain and nausea. The percentage of total adverse effects was significantly greater in the 22-g than in the 25-g needle group. The percentage of patients with headache was higher in the 22-g than in the 25-g group, but this difference was not statistically significant. Only 19% of private practice groups and 17% of academic centers use 25-g needles; the remainder use 20-g or 22-g needles.

Modification of tumor necrosis factor and interleukin-1 productivity in macrophages from hepatoma-bearing rats by dietary proteins

Changes in tumor necrosis factor (TNF) and interleukin-1 (IL-1) productivity in resident peritoneal macrophages and those in the serum lipid levels were traced for up to 14 days after subcutaneous implantation of hepatoma (AH109A) cells to rats kept on a 20% casein diet (20C). Elevated levels of serum triglyceride and cholesterol were found to be associated with growth of the solid hepatoma. The ability of macrophages to produce TNF and IL-1 rose twice at both the early (days 2–4) and late (day 14) stages. To examine the effects of dietary proteins, hepatoma-free (normal) and -bearing rats were maintained on the 20C or a 20% gluten diet (20G) for 14 days after sham or hepatoma implantation. No significant changes were noticed in the serum lipid levels between the 20C and 20G groups in either hepatoma-free or -bearing rats. TNF and IL-1 production by macrophages from hepatoma-bearing rats was significantly higher in the 20C group than in the 20G group. These results indicate that TNF and IL-1 productivity in macrophages is enhanced by hepatoma implantation and that their productivity may be modified by dietary proteins in the hepatoma-bearing state.

Qualitative and quantitative effects of dietary proteins on hyperlipidemia and proteinuria in nephritic rats

Effects of qualitative and quantitative differences in dietary poteins on hyperlipidemia and proteinuria were studied in rats with nephrotoxic serum nephritis. Dietary proteins examined were milk casein, whole egg protein, soy protein isolate and wheat gluten. Rats were maintained on experimental diets for 14 days after an injection of nephrotoxic serum to induce nephritis. In the qualitative study, almost the same extent of growth and urinary protein excretion was observed in a 20% casein (20C), egg protein (20E) and a soy protein (20S) group. Growth and protein excretion of a 20% gluten (20G) group were suppressed compared with that of the other three groups. The serum lipid levels were highest in the 20E group and lowest in the 20G group. In the quantitative study, 8.5% protein diets, in general, ameliorated hyper lipidemia and proteinuria but retarded the growth of rats compared with the corresponding 20% protein diets, except for an 8.5% egg protein diet that did not suppress the growth. These results suggest that amino acid-balanced low protein diets improve hyperlipidemia and proteinuria without growth retardation in nephritic rats.

A feeding experiment on laboratory-bred male cynomolgus monkeys. I. Morphometrical study

Effects of restricted feeding on the growth of laboratory-bred male cynomolgus monkeys (Macaca fascicularis) aged between one year and four years were studied morphometrically. A series of 11 variables representing physical elements were measured. Before 2.5 years of age, the amount of commercial diet (Type AS, 382kcal/100g and 28.1% of crude protein, Oriental Yeast Co. Ltd.) per day was restricted to 50g (group A), 30g (group B) or 20g (group C) and increased to 100g (group A), 50g (group B) or 40g (group C) respectively at 2.5 years old. Throughout the experimental period ca 100g of apples and oranges per day were provided. Significant differences in body weight between group A and C were detected excepting the early period of the experiment. Although the slight suppression in weight gain was observed in group B during the second trimester of the experiment, body weight increased gradually after increasing the amount of food and no significant difference from A was observed at four years of age. The minimum requirement of diets is judged to be 30g/day before two years old and 50g/day over two years old in the laboratory-bred male cynomolgus monkey. Moreover, the suppressive effects of restricted feeding were most significant on the growth of the limbs and, secondarily, on the growth of the trunk. Practically no effect on the growth of the head was observed.