Moderate Traction Research Articles

Canine pillar bone bearing traction method of skull external fixator combined with nickel-titanium memory alloy spring for unilateral cleft lip and palate with severe facial skeletal hypoplasia

Background: For unilateral cleft lip and palate severe midfacial skeletal dysplasia, external skull fixator combined with nickel titanium memory alloy spring was used to treat canine pillar bone bearing traction. Methodology: Patients (n = 200) with unilateral cleft lip and palate and severe midfacial skeletal hypoplasia who were treated in our hospital within three years were divided into control group (treated with trans suture traction osteogenesis) while the observation group was treated with skull external fixator combined with nickel titanium memory alloy spring supporting force traction of canine bone. Results: After applying significantly different traction forces to the maxillary tissues on both sides of the patient, the patient was treated with appropriate traction correction, orthodontic treatment and moderate traction on the facial arch to effectively reduce the recurrence of the disease after surgery. Compared with the control group, the curative effect in all aspects was better and the asymmetry rate was lower. Conclusion: Canine strut bone traction method of external skull fixation combined with nickel-titanium memory alloy spring was applied for severe facial skeletal dysplasia caused by unilateral cleft lip and palate. For this purpose, reasonable and scientific treatment methods were provided for early correction and treatment of the disease. Keywords: External fixator of skull; nickel titanium memory alloy spring; bone bearing traction of canine pillar; unilateral cleft lip and palate; severe midfacial skeletal dysplasia; clinical research.

Office Rigid Laryngoscopy as a Predictor for Glottic Exposure in Microlaryngoscopy.

Good glottic exposure is a prerequisite for a good microlaryngeal surgery. Often this is difficult to predict preoperatively. This study aims to evaluate the utility of office-based rigid laryngoscopy (70°) as a screening tool to predict laryngeal exposure during micro laryngoscopy. Sixty-nine patients underwent office-based rigid laryngeal examination followed by micro laryngoscopic surgery for benign vocal cord lesions. Office-based laryngoscopy was classified as grade 1 when the entire glottis with anterior commissure (AC) was visualized without undue traction of tongue; grade 2 when AC was visualized only during phonation and with some traction of tongue and grade 3 when there is an inability to visualise the glottis adequately despite moderate traction of tongue and the examination was completed using a flexible scope. These were correlated with laryngeal exposure during micro laryngoscopy. 42 patients were categorized as grade 1 out of which 39 (93%) had a favourable laryngeal exposure (class 1) while only 3 (7%) had a partially favourable exposure (class 2). 18 patients were categorized as grade 2 out of which 12(66%) had a favourable exposure (class 1) as against 6 (33%) who had a partially favourable exposure (class 2). Nine of our patients were categorized as grade 3 out of which all 9 (100%) had an unfavourable exposure (class 3) requiring angled tele laryngoscopy to complete the surgery. A strong correlation between office-based laryngoscopic grading and exposure during operative laryngoscopy was obtained statistically (Cramer's V test, V = 0.746). Office examination with a 70° telescope is a good predictor of glottic exposure during micro laryngoscopy. We believe that the ease of performing a micro laryngoscopy in the operating room is directly proportional to the ease of doing laryngoscopy in the office.

Rheology of growing axons

The growth of axons is a key process in neural system development, which relies upon a subtle balance between external mechanical forces and remodeling of cellular constituents. A key problem in the biophysics of axons is therefore to understand the overall response of the axon under stretch, which is often modeled phenomenologically using morphoelastic or viscoelastic models. Here, we develop a microscopic mixture model of growth and remodeling based on protein turnover and damage to obtain the macroscopic rheology of axonal shafts. First, we provide an estimate for the instantaneous elastic response of axons. Second, we predict that under moderate traction velocities, the axonal core behaves like a viscoelastic Maxwell material whose rheological parameters can be expressed in terms of the microscopic properties. Third, for larger velocities, we show that failure takes place due to extensive damage.

Traction Bronchiectasis/Bronchiolectasis on CT Scans in Relationship to Clinical Outcomes and Mortality: The COPDGene Study.

Background The clinical impact of interstitial lung abnormalities (ILAs) on poor prognosis has been reported in many studies, but risk stratification in ILA will contribute to clinical practice. Purpose To investigate the association of traction bronchiectasis/bronchiolectasis index (TBI) with mortality and clinical outcomes in individuals with ILA by using the COPDGene cohort. Materials and Methods This study was a secondary analysis of prospectively collected data. Chest CT scans of participants with ILA for traction bronchiectasis/bronchiolectasis were evaluated and outcomes were compared with participants without ILA from the COPDGene study (January 2008 to June 2011). TBI was classified as follows: TBI-0, ILA without traction bronchiectasis/bronchiolectasis; TBI-1, ILA with bronchiolectasis but without bronchiectasis or architectural distortion; TBI-2, ILA with mild to moderate traction bronchiectasis; and TBI-3, ILA with severe traction bronchiectasis and/or honeycombing. Clinical outcomes and overall survival were compared among the TBI groups and the non-ILA group by using multivariable linear regression model and Cox proportional hazards model, respectively. Results Overall, 5295 participants (median age, 59 years; IQR, 52-66 years; 2779 men) were included, and 582 participants with ILA and 4713 participants without ILA were identified. TBI groups were associated with poorer clinical outcomes such as quality of life scores in the multivariable linear regression model (TBI-0: coefficient, 3.2 [95% CI: 0.6, 5.7; P = .01]; TBI-1: coefficient, 3.3 [95% CI: 1.1, 5.6; P = .003]; TBI-2: coefficient, 7.6 [95% CI: 4.0, 11; P < .001]; TBI-3: coefficient, 32 [95% CI: 17, 48; P < .001]). The multivariable Cox model demonstrated that ILA without traction bronchiectasis (TBI-0-1) and with traction bronchiectasis (TBI-2-3) were associated with shorter overall survival (TBI-0-1: hazard ratio [HR], 1.4 [95% CI: 1.0, 1.9; P = .049]; TBI-2-3: HR, 3.8 [95% CI: 2.6, 5.6; P < .001]). Conclusion Traction bronchiectasis/bronchiolectasis was associated with poorer clinical outcomes compared with the group without interstitial lung abnormalities; TBI-2 and 3 were associated with shorter survival. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Lee and Im in this issue.

A novel laparoscopic assisted mediastinal dissection with gastric tube inversion technique for gastric tube cancer reconstructed through a retrosternal route.

A median sternotomy is often performed in patients with gastric tube cancer reconstructed through the retrosternal route; however, this procedure is invasive and has the risk of severe infectious complications. To overcome these problems, we created a novel method to perform the reconstructed gastric tube resection using a gastric tube inversion technique combined with a laparoscopic mediastinal approach. After the duodenum was divided, the oral side of the cut end was sutured with silken threads for traction. The gastric tube was dissected from the caudal side under a laparoscopic mediastinal approach, whereas the cervical esophagus was taped. After the adhesion between the middle side of the posterior sternum and the reconstructed gastric tube was dissected to the cervix, the gastric tube was inverted by guiding and pulling the thread toward the cervical side. Sharp dissection was facilitated between the inverted gastric tube and the surrounding organs under moderate traction and a favorable surgical view. We have performed this procedure and evaluated the short‐term outcomes in six cases. The laparoscopic mediastinal approach was completed without a median sternotomy in all six cases. Restorable intraoperative lung injury was observed in one case and no major vessel injuries were observed. The postoperative course was satisfactory with a 29.5‐day median length of hospital stay (range, 16‐60 days). The gastric tube inversion technique combined with the laparoscopic mediastinal approach for patients with retrosternal‐reconstructed gastric tube cancer was shown to be safe and less invasive and should be considered in resection of the reconstructed gastric tube.

Progression of traction bronchiectasis/bronchiolectasis in interstitial lung abnormalities is associated with increased all-cause mortality: Age Gene/Environment Susceptibility-Reykjavik Study

PurposeThe aim of this study is to assess the role of traction bronchiectasis/bronchiolectasis and its progression as a predictor for early fibrosis in interstitial lung abnormalities (ILA). MethodsThree hundred twenty-seven ILA participants out of 5764 in the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study who had undergone chest CT twice with an interval of approximately five-years were enrolled in this study. Traction bronchiectasis/bronchiolectasis index (TBI) was classified on a four-point scale: 0, ILA without traction bronchiectasis/bronchiolectasis; 1, ILA with bronchiolectasis but without bronchiectasis or architectural distortion; 2, ILA with mild to moderate traction bronchiectasis; 3, ILA and severe traction bronchiectasis and/or honeycombing. Traction bronchiectasis (TB) progression was classified on a five-point scale: 1, Improved; 2, Probably improved; 3, No change; 4, Probably progressed; 5, Progressed. Overall survival (OS) among participants with different TB Progression Score and between the TB progression group and No TB progression group was also investigated. Hazard radio (HR) was estimated with Cox proportional hazards model. ResultsThe higher the TBI at baseline, the higher TB Progression Score (P < 0.001). All five participants with TBI = 3 at baseline progressed; 46 (90 %) of 51 participants with TBI = 2 progressed. TB progression was also associated with shorter OS with statistically significant difference (adjusted HR = 1.68, P < 0.001). ConclusionTB progression was visualized on chest CT frequently and clearly. It has the potential to be the predictor for poorer prognosis of ILA.

Traction Bronchiectasis/Bronchiolectasis is Associated with Interstitial Lung Abnormality Mortality

PurposeTo investigate if the presence and severity of traction bronchiectasis/bronchiolectasis are associated with poorer survival in subjects with ILA. MethodThe study included 3,594 subjects (378 subjects with ILA and 3,216 subjects without ILA) in AGES-Reykjavik Study. Chest CT scans of 378 subjects with ILA were evaluated for traction bronchiectasis/bronchiolectasis, defined as dilatation of bronchi/bronchioles within areas demonstrating ILA. Traction bronchiectasis/bronchiolectasis Index (TBI) was assigned as: TBI = 0, ILA without traction bronchiectasis/bronchiolectasis: TBI = 1, ILA with bronchiolectasis but without bronchiectasis or architectural distortion: TBI = 2, ILA with mild to moderate traction bronchiectasis: TBI = 3, ILA and severe traction bronchiectasis and/or honeycombing. Overall survival (OS) was compared among the subjects in different TBI groups and those without ILA. ResultsThe median OS was 12.93 years (95%CI; 12.67 – 13.43) in the subjects without ILA; 11.95 years (10.03 – not reached) in TBI-0 group; 8.52 years (7.57 – 9.30) in TBI-1 group; 7.63 years (6.09 – 9.10) in TBI-2 group; 5.40 years (1.85 – 5.98) in TBI-3 group. The multivariable Cox models demonstrated significantly shorter OS of TBI-1, TBI-2, and TBI-3 groups compared to subjects without ILA (P < 0.0001), whereas TBI-0 group had no significant OS difference compared to subjects without ILA, after adjusting for age, sex, and smoking status. ConclusionsThe presence and severity of traction bronchiectasis/bronchiolectasis are associated with shorter survival. The traction bronchiectasis/bronchiolectasis is an important contributor to increased mortality among subjects with ILA.

Suture techniques and patch materials using an in-vitro model for watertight closure of in-utero spina bifida repair

PurposeDespite proven benefits of in-utero spina bifida (SB) repair, ≥30% of children at birth have Chiari II malformation or cerebrospinal fluid (CSF) leakage from the repair site. Our study's purpose was to determine CSF pressures in the myelomeningocele sac during mid-gestation in order to design an in-vitro model for evaluating different surgical methods used for watertight closure during in-utero SB repair. MethodsCSF pressures were measured during in-utero SB repair at mid-gestation. An in-vitro chicken thigh model, simulating fetal tissue, tested watertight closure when attached to the base of a water column. Primary closure methods were evaluated using defect sizes of 20 × 3 mm for minimal traction or 20 × 8 mm for moderate traction. Additionally, 3 common in-utero repair patches were compared using 15 × 15 mm defects. ResultsUsing 6–12.5 cm pre-determined CSF pressures, 165 in-vitro experiments were performed. Regardless of methodology we found that in 66 primary-based closures that minimal versus moderate wound edge traction provided better seals. The locking method was superior to the non-locking technique for watertight closure in 99 patch-based closures. ConclusionsMinimal wound edge traction was best for primary closures, and locking sutures ideal for patch-based closures, however surgical techniques should be individualized to improve upon clinical outcomes.

Effect of sub-surface hydrogen on intrinsic crack tip plasticity in aluminium

ABSTRACTThe effects of sub-surface hydrogen and mixed mode loading on dislocation emission in aluminium are studied using a combination of techniques including crack simulations with an empirical interatomic potential, generalised stacking fault energy (GSF) calculations, with empirical interactions and Density Functional Theory, and the model by Rice which links the critical stress intensity factor to the unstable stacking energy. The crack orientation is and the loading is composed of a moderate traction along and a shear along , such that Shockley partials are emitted along the crack plane. The role of the relaxations around the H atoms and of the concentration of H in the glide plane, in the GSF calculation, is revealed by comparing Rice's model to the results of brute force simulations. The enhanced GSF is then calculated ab initio. The conclusion is a large decrease of the critical load to emit a dislocation, due to the displacement transverse to the glide direction. The effect of sub-surface hydrogen is negligible with respect to the mechanical one.

SURGICAL MANAGEMENT BY STANDING LAPAROSCOPY AND INGUINAL CELIOTOMY APPROACH OF THE CRYPTORCHID CANADIAN PONY STALLION – CASE REPORT

SURGICAL MANAGEMENT BY STANDING LAPAROSCOPY AND INGUINAL CELIOTOMY APPROACH OF THE CRYPTORCHID CANADIAN PONY STALLION – CASE REPORT Cornel IGNA1*, Roxana DASCALU1, Daniel BUMB1, Bogdan Sicoe1, Larisa SCHUSZLER1 1 Banat’s University of Agricultural Science and Veterinary Medicine, “King Michael I of Romania” from Timisoara, Romania *Corresponding author, e-mail: ignacornel@gmail.com Keywords: cryptorchidectomy, inguinal celiotomy, laparoscopic, stallion pony Introduction: Laparoscopic surgery has become an accepted method of identification and removal of intra-abdominal testes in the horse. Wilson and Madison – 1989 describe the use of laparoscopy to diagnose an abdominal retained testes. Since then numerous laparoscopic cryptorchidectomy techniques have been described. Aims: In the encountered specialty literature there are few reports in which standing laparoscopic cryptorchidectomy could not be performed in stallions including miniature horse too. Because there are no informations regarding laparoscopic surgery in large animals in romanian literature this report describes the surgical management of a Canadian pony diagnosed with partial abdominal unilaterally cryptorchidism at which laparoscopic castration has failed and the removal of the retained testicle has been made through inguinal celiotomy. Materials and Methods: A 4-year-old unilaterally cryptorchid Canadian pony was admitted for castration. The left testis was in the scrotum, but neither the right testis nor the right epididymis could be located by external palpation of the right inguinal canal. The proposed treatment was laparoscopic cryptorchidectomy with pony standing in stock. With a long-handled forceps inserted into the abdominal cavity, the testis cord is gently grasped and moderate traction without success in bringing the testicle into the abdomen - retained testis. After the failure of laparascopic cryptorchidectomy but having an exact diagnosis - partial abdominal unilaterally cryptorchidism, we have proceeded to open cryptorchidectomy via inguinal approach with pony anesthetized and positioned in dorsal recumbency. Results: This case report reveals that the major disadvantage of the cryptorchidectomy by flank approach is the inability to remove an inguinally retained testis. Conclusion: If the location of the testis is unknown, the standing laparoscopic diagnose can be decisive. Cryptorchidectomy via inguinal approach and noninvasive method for identifying and everting the vaginal process by traction of the inguinal extension of the gubernaculum testis are commonly facile procedure.

Anatomical basis of the risk of injury to the right laryngeal recurrent nerve during thoracic surgery

Despite the intrathoracic part being short, the right laryngeal recurrent nerve is often injured during thoracic surgery. The aim of this cadaver study was to understand the mechanisms of right laryngeal recurrent nerve injuries during thoracic surgery and to describe anatomical landmarks for its preservation. Dissections were performed on 10 fresh human cadavers. A right anterolateral thoracic wall segment was removed, preserving the first rib. Dissections were carried out to identify the following structures: first rib, esophagus, trachea, right main bronchus, right brachiocephalic and subclavian vessels, azygos vein, phrenic nerve, vagus nerve, and right laryngeal recurrent nerve. The distance between the origin of the right laryngeal recurrent nerve and its adjacent structures was assessed. Moderate traction of the thoracic part of the vagus nerve resulted in a downward translation of the right laryngeal recurrent nerve's origin. In such conditions, the right laryngeal recurrent nerve's origin was distant of 14.8 mm (±2.89 mm) from the subclavian artery. Intraoperative incidence of right laryngeal recurrent nerve direct injury could be decreased by understanding the detailed course of its intrathoracic part. Moreover, traction on the intrathoracic part of the right vagus nerve may result in indirect lesions of the right laryngeal recurrent nerve: stretch induced lesions and nerve vasculature's lesions.

Piège en traumatologie : la luxation C1–C2

We reported the case of asymptomatic traumatic atlantoaxial dislocation in a 14-year-old woman. Clinical diagnosis of this uncommon dislocation is difficult and often made late. The early diagnosis by CT scan is necessary to avoid secondary aggravation. Integrity of the transverse ligament of the atlas is a determining factor for atlantoaxial stability and allows orthopaedic treatment after reduction using moderate traction on the head.

The middle layer of lumbar fascia can transmit tensile forces capable of fracturing the lumbar transverse processes: An experimental study

Background Transversus abdominis and its aponeurotic attachment to the lumbar transverse processes via the middle layer of lumbar fascia are of proposed clinical and biomechanical importance. Moderate traction on these structures (simulating submaximal contraction of transversus abdominis) is reported to influence segmental motion, but their tensile capacity is unknown and the effects of sudden, maximal traction on these attachments and the transverse processes are uncertain. Methods In 15 embalmed cadaver abdomens, the middle layer of lumbar fascia was isolated, gripped and rapid tension applied in either a lateral or posteroanterior direction (simulating forces that may produce avulsion and traumatic fractures). Peak forces prior to tissue failure were recorded and the gross effects of traction documented. Findings Lumbar transverse process fractures were produced in all specimens; by transverse traction in 50% of tests and posteroanterior force in 80%. In the remainder the middle layer of lumbar fascia was torn. Mean transverse and posteroanterior peak forces reached in the middle layer of lumbar fascia prior to failure were 82 N (range 20–190 N) and 47 N (range 25–70 N), respectively. Interpretation The middle layer of lumbar fascia can transmit substantial tensile forces to lumbar vertebrae, capable of transverse process fracture under experimental conditions. Tensile capacity is likely to be even greater in-vivo. This suggests tranversus abdominis and the middle layer of lumbar fascia can strongly influence vertebral motion, should be incorporated in biomechanical models of the spine and considered as potential contributors to transverse process fractures by avulsion.

Corrective intra-articular surgery in juvenile femur head epiphysiolysis

Treatment of severely slipped capital femoral epiphysis depends on the individual pathoanatomic and pathophysiologic conditions. Since the femoral neck vessels remain intact in chronic slip, they should be preserved whenever possible. Bilateral chondrolysis developed in 1 of our 9 cervical osteotomy patients. Long-term radiologic and clinical findings after a cervical osteotomy do not differ appreciably from those after an Imhäuser osteotomy, in some cases, with incomplete realignment of the femoral head-acetabulum relation. Apparently, not only the "quantitative" factor but also the "qualitative" factor plays an important role in epiphyseal separation. By contrast, severe acute slip is a severe irritation of the joint accompanied by intra-articular bleeding and rupture of the femoral neck vessels. Good results are achieved after immediate operative decompression, controlled reduction, and stable fixation of the epiphysis, providing anatomic realignment of the femoral head-acetabulum relation is not forced, but rather carried out only to the limit of tolerance without leverage maneuver and under moderate traction and vision. Epiphyseal necrosis developed after conventional open reduction in 2 of our 16 patients with acute slip. No cases of epiphyseal necrosis have been observed to date in any of our patients (N = 5) treated with this new technique of controlled reduction (i.e., partial reduction in "acute chronic slip").

Laser Assistance for Extraction of Chronically Implanted Endocardial Leads: Infectious versus Noninfectious Indications

Powered sheaths, including Excimer laser sheaths, were introduced for the removal of transvenous pacing and defibrillator leads. The purpose of this study was to develop an algorithm to better predict which patients are likely to benefit from these devices. We reviewed 283 consecutive patients in whom a total of 500 leads (302 pacing and 198 defibrillator leads) were extracted over a 5-year period at our operative facilities. Laser assist was utilized whenever moderate traction failed. In 128 patients, 203 leads were removed for noninfectious indication. In 155 patients, 297 leads for infectious indications, including sepsis 22% (111), pocket infection 23% (115), and erosion 14% (71). Laser assistance was required for 6%+/- 5% (+/- 95% confidence interval) of septic leads, 51%+/- 7% of leads associated with erosion or pocket infection and 60%+/- 7% of noninfected leads (P = 0.001). Laser assistance was necessary more often for leads implanted >12 months (53%+/- 5%) than 12 months or less (6%+/- 5%) (P = 0.001) and for ventricular (52%+/- 6%) compared to atrial (35%+/- 7%) leads (P = 0.001). Chronically implanted leads (>12 months), especially noninfected leads and leads associated with erosion or pocket infection, should be referred for extraction with powered sheaths to ensure successful removal. However, leads that are associated with systemic sepsis can generally be removed without powered sheaths.

Characteristics of fetal heart rate changes during the expulsive stage of bovine parturition in relation to fetal outcome

Abstract Objective To characterize fetal heart rate (FHR) patterns of nonacidotic (N-AC) and acidotic (AC) calves during the expulsive stage of parturition. Animals 32 calves born to heifers, either unassisted or by moderate traction. Procedure Cardiotocograms (CTG) evaluated qualitatively (visual) and quantitatively by a moving window technique (width 10, shift 5 minutes) for baseline FHR, variability, and periodic alterations (accelerations and decelerations). Results Significant differences were apparent between increase in baseline FHR of N-AC and AC calves; change in FHR (Δ-FHR), taking into account individual FHR, is a more discriminating parameter. The predominant reaction to uterine contraction is a decrease in FHR; variable decelerations were the most common type in both groups, and late decelerations were seen only in AC calves. Additional characteristics of variable decelerations were more frequently seen in AC calves. Conclusions CTG parameters during expulsion can discriminate between AC and N-AC calves, but specific characteristics are not exclusively restricted to AC or N-AC calves. Clinical Relevance CTG recordings during bovine parturition in cattle provide information on the fetal condition and can be used in the future to study the effects of medication and manipulations to the fetus. (Am J Vet Res 1996;57:1373-1381)

A staged approach to long gap esophageal atresia employing a spiral myotomy and delayed reconstruction of the esophagus: An experimental study

In beagle dogs, the cervical esophagus was divided 5 cm cranial to the thoracic inlet employing a stapler. The distal esophageal stump was attached to the external surface of the trachea. A spiral myotomy (2 1/2 revolutions) was made in a 3-cm long segment constituting the distal end of the proximal esophageal segment. This was twisted on a bias with the muscle edges approximated by interrupted stitches to cover the denuded submucosal layer. With moderate traction, this segment could be elongated to a length of 5 cm. A subcutaneous tunnel was created in the anterior chest to accommodate the reconstructed proximal esophageal segment (under slight traction), with its distal end forming a cutaneous esophagostomy. A gastrostomy was created using a Gauderer button (Bard Interventional Products, Billerica, MA) for feeding. After 3 weeks, the proximal esophageal segment was mobilized and removed from the subcutaneous tunnel. The distal esophageal segment was freed from the trachea and 5 to 8 cm of its proximal end was excised. The proximal (myotomized) esophagus was brought down to the stump of the remaining distal esophagus and an anastomosis formed in an end-to-end fashion. Oral feeding was reestablished within 1 week. Prolonged ingestion, observed soon after operation, gradually improved. During a period of 1 to 6 months after the operation, motility of the myotomized segment was tested by barium swallow and manometry. There was neither diverticulum formation nor stenosis. Transit of contrast material in the myotomized segment was smooth and rapid. Manometry demonstrated preservation of motility in the myotomized segment of the esophagus.(ABSTRACT TRUNCATED AT 250 WORDS)

Retinal Cryoprobe in Orbital Tumor Management

We used the retinal cryoprobe in the surgical management (biopsy and excision) of orbital and ocular adnexal tumors in four patients. The strong bond between the cryoprobe tip and the tumor allowed application of moderate traction to the tumors, facilitating their removal. The amount of traction on the tumor or cyst appeared to be much greater than that caused by forceps or clamps. In one case, however, marked traction with the cryoprobe caused rupture of the tumor capsule. In another case, in which a cyst wall was entered during dissection, we applied the cryoprobe to the opening, sealing the hole with an ice ball, to keep the cyst from collapsing. Histopathologic structure was not altered by cryoprobe applications.

The use of the obstetric forceps

T HE obstetric forceps, like the automobile, may be indispensabIe, if properIy used, in the saving of Iife and human effort and suffering; and, improperIy used, it may be the instrument of many unnecessary deaths. There are six principles essentia1 to the safe and successful use of the forceps: I. The cervix must be fuIIy diIated, that is, its passage must be Iarge enough to shp over the head at the pIane of maximal diameters without retarding pressure. It is very easy to Iet one’s obstetric conscience sIip in this direction untiI, by degrees, it becomes habitua1 to appIy the forceps when the cervica1 passage Iacks 2 or even 4 cm. of compIete diIatation. It shouId be remembered that a rim of cervix I cm. wide diminishes every diameter of the passage by 2 cm. Dragging the head through this inadequate opening resuIts at least in Laceration of the cervix, and at most, in fata intracrania1 strains and resultant hemorrhage. 2. The forceps must be properIy apphed. It may be diIIicuIt (in rare cases, impossibIe) to appIy the forceps symmetricahy to the head, but repeated attempts shouId be made unti1 the sagitta1 suture coincides with the vertical pIane of the forceps. Failure to effect this adjustment accounts for most of the cases of sIipping of the forceps. ProperIy appIied, it is aImost impossibIe (impossible within the justifiabIe Iimits of force of traction) to puI1 the forceps off the head. Improper appIication results in a mechanica maladjustment somewhat Iike using the wrong wrench on a boIthead-the wrench is aImost certain to siip, or to hoId onIy because of damage to the boIt. Pressure injuries to the soft parts of the feta1 head may be inevitabIe; but gashes and tearing off of ears, Iips, etc., shouId never occur. 3. Force in the appIication and adjustment of the forceps is never permissibIe. If diffrcuIty is encountered, something is wrong-the position of the head has changed, the forceps has sIipped outside of the cervix instead of inside it, the blade has caught against an ear or some other prominence, or the whole route of the introduction of the bIade has been wrong. Proper introduction of the forceps involves a knowIedge of the topography and axis of the birth cana1, and requires a technique of Ietting the bIade foIIow the line of Ieast resistance (as in sounding of the urethra). Any attempt at forcibIe steering is apt to Iead the top of the bIade into a hopeIessIy bIocked situation. It is better to dislodge the head and change its position than to attempt to force the forceps past any serious obstacIe. 4. The head shouId never be compressed by squeezing on the handIes of the forceps. It is very easy, in making traction, to appIy great IateraI pressure on the head by invoIuntary squeezing. Once a snug and accurate ht. of the bIades has been accompIished, nothing is gained by further compression : in other words, excessive compression adds no security against sIipping. 3. Force in extraction shouId never be empIoyed. It is diffrcuIt to estimate the tractive force which one employs in actual practice, so that dynamometric figures are of no great practica1 vaIue. Force sufficient to move the patient on the tabIe is excessive. Moderate traction wiI1 cause the peIvis to sIide on the fat of the buttocks, so that, especiaIIy in obese individuaIs, the apparent to-and-fro movement of the peIvis may be quite great; but the buttocks