Thermal osteonecrosis and bone drilling parameters revisited

INTRODUCTION

During the drilling of the bone, the temperature could increase above 47 degrees C and cause irreversible osteonecrosis. The result is weakened contact of implants with bone and possible loss of rigid fixation. The aim of this study was to find an optimal condition where the increase in bone temperature during bone drilling process would be minimal.

MATERIALS AND METHODS

Influence of different drill parameters was evaluated on the increase of bone temperature. Drill diameters were 2.5, 3.2 and 4.5 mm; drill speed 188, 462, 1,140 and 1,820 rpm; feed-rate 24, 56, 84 and 196 mm/min; drill point angle 80 degrees , 100 degrees and 120 degrees and external irrigation with water of 26 degrees C.

RESULTS

Combinations of drill speed and drill diameter with the use of external irrigation produced temperatures far below critical. Without external irrigation, temperature values for the same combination of parameters ranged 31.4-55.5 degrees C. Temperatures above critical were recorded using 4.5 mm drill with higher drill speeds (1,140 and 1,820 rpm). There was no statistical significance of different drill point angles on the increase or decrease of bone temperature. The higher the feed-rate the lower the increase of bone temperature.

CONCLUSIONS

The external irrigation is the most important cooling factor. With all combinations of parameters used, external irrigation maintained the bone temperature below 47 degrees C. The increase in drill diameter and drill speed caused increase in bone temperature. The changes in drill point angle did not show significant influence in the increase of the bone temperature. With the increase in feed-rate, increase in bone temperature is lower.

The periosteum. Part 1: Anatomy, histology and molecular biology

The periosteum is a thin layer of connective tissue that covers the outer surface of a bone in all places except at joints (which are protected by articular cartilage). As opposed to bone itself, it has nociceptive nerve endings, making it very sensitive to manipulation. It also provides nourishment in the form of blood supply to the bone. The periosteum is connected to the bone by strong collagenous fibres called Sharpey's fibres, which extend to the outer circumferential and interstitial lamellae of bone. The periosteum consists of an outer "fibrous layer" and inner "cambium layer". The fibrous layer contains fibroblasts while the cambium layer contains progenitor cells which develop into osteoblasts that are responsible for increasing bone width. After a bone fracture the progenitor cells develop into osteoblasts and chondroblasts which are essential to the healing process. This review discusses the anatomy, histology and molecular biology of the periosteum in detail.

Intestinal duplications--experience in 6 cases

Intestinal duplications are rare congenital anomalies, and most of them are detected in the first 2 years of life or antenatally. The clinical presentation depends on location, size, and the presence of ectopic gastric mucosa. Ultrasound scans during pregnancy result in a higher rate of antenatally detected duplications which allows early treatment and avoidance of possible complications. Resection of the duplication without adjacent bowel should be the treatment of choice. En bloc resection or partial excision with mucosectomy is advised in some cases. We present our experience with 6 patients treated in our institution from February 2002 to October 2005.

The value of cholinesterase activity after Kasai operation

Cholinesterase (ChE) is an enzyme synthesized in the liver. The aim of this study was to determine the value of ChE as an index of liver function. We measured the ChE activity as well as the values of bilirubin, alkaline phosphatase, gamma-glutamyl transpeptidase, aminotransferases and albumin before and 7 days after Kasai operation in 25 infants with biliary atresia. The increased activity of ChE in plasma after Kasai operation was accompanied by a decrease of other measured values ( P<0.0001), except for albumin. We can conclude that the increase of ChE activity together with the decrease of bilirubin, alkaline phosphatase and gamma-glutamyl transpeptidase show early improvement of liver function after Kasai operation. ChE activity can be used to assess liver function in terms of synthesis.

Successful early pyeloplasty in infants

BACKGROUND

Early pyeloplasty for the treatment of congenital ureteropelvic junction obstruction to maximize nephron salvage is justified only if potential hazards of operating on small infants are avoided.

METHODS

The records were analyzed of all infants who underwent pyeloplasty over a 5-year period. Open pyeloplasty was performed if collecting systems had deteriorated or were demonstrated to be obstructed; it was also performed for severe cases of hydronephrosis. Outcome of surgery in the younger infant (patients <2 months of age) was compared with the older infant group (patients >2 months of age). Preoperative evaluation in case of mild or moderate hydronephrosis was directed toward ruling out a non-obstructed collection system and included voiding cystourethrography, and serial ultrasonography and/or dual isotope diuretic renography. Postoperative assessment consisted of serial ultrasonography and/or nuclear imaging to confirm decompression and relief of obstruction.

RESULTS

A total of 24 pyeloplasties were performed on 22 patients in the younger infant group (two bilateral) and 30 were performed on 27 infants in the older infant group (three bilateral). The only significant differences between the groups were as follows: patients in the younger infant group were likely to present in utero (75%, p = 2.69), whereas those in the older infant group were more likely to present with a urinary tract infection (48%, p = 4.12). During follow-up examination, 23 renal units in the younger infant group and 24 in the older infant group were judged to be stable or improved. Four kidneys were not salvaged after pyeloplasty, one in the younger infant group and three in the older infant group.

CONCLUSIONS

Good results of pyeloplasties performed in the infants in this series support early correction of ureteropelvic junction obstruction in infants.

[Analysis of results of surgical treatment of malleolar fractures]

Late results of operatively treated malleolar fractures were analyzed. 101 patients were operated on, 58 (57.4%) were available for follow-up. There were 5 patients with A-type fractures according to Weber's classification, 28 with type-B and 25 with type-C fractures. One year or more after the treatment the patients were evaluated on follow-up checks where ranges of ankle dorsiflexion, plantar extension, pronation and supination were recorded, circumference of the injured ankle was measured and the patients were interviewed about subjective complaints. Normal range of motion of the injured ankle (normal range of motion represented by the healthy ankle) was found only in patients with type-A fractures while in other two groups the patients had significantly decreased motility of the injured ankle (P < 0.05). The circumference of the injured ankle was increased in most patients with 25.9% patients ankles being 20 mm or more thicker than the uninjured side. Only seven patients (12.1%) were without subjective complaints while other patients experienced pain with load, pain with weather changes, swelling of the ankle etc. Malleolar fractures still represent a significant surgical problem and only an early operation, anatomic reduction and fixation as well as proper rehabilitation guarantee good results.

[Treatment of pseudarthroses of the olecranon with the anatomical hook plate]

We report the results in seven patients treated surgically for nonunion of the olecranon. Four nonunions occurred after primary treatment with tension band wiring and three nonunions occurred after open reduction internal fixation with plates and screws or lag screws only. All patients were treated with cancellous bone grafting and open reduction internal fixation using anatomical hook plates. All nonunions united within 6 months after the treatment. In all patients the range of motion of the elbow improved significantly.

[Posterior sagittal anorectoplasty (PSARP) in children with high anal atresia]

Anorectal anomalies are highly significant (the incidence of 1:3000 infants). The knowledge of the factors related to fecal continence encouraged the introduction of new surgical approaches in the second half of this century. With high supralevator anorectal anomalies the percentage of incontinence in children was earlier 50-80% although in all surgical procedures efforts were made to reconstruct the normal anatomy of the small pelvis. It was only in 1982 that by the PSARP method the anatomic reconstruction was achieved. In this operation an electric stimulator is used to identify the entire muscle-sphincter complex (external sphincter, the cross-striated muscle complex and the levator musculature) and then by stimulation of muscles a mobilized and modeled rectum is inserted into the muscle-sphincter complex. During the ten-year application of the PSARP method 15 children underwent the operation, of which 14 boys and 1 girl. The girl had rectovaginal fistula and 11 boys had rectourethral fistula. More than 70% of our children showed accompanying anomalies. Control examinations of children older than 3 years show the 67% continence in our children operated by the Pena-de Vries method.

[Laparoscopic cholecystectomy in a child with sickle cell disease]

Laparoscopic cholecystectomy has become the procedure of choice for the removal of the diseased gallbladder in children. Its use in small children and infants is rare. At the Department of Pediatric Surgery of the Medical faculty in Zagreb five children underwent laparoscopic cholecystectomy. One of them was a five year old boy with sickle cell disease and cholelithiasis. Before the advent of laparoscopy, few children with sickle cell disease and cholelithiasis underwent cholecystectomy, because of the high morbidity associated with open cholecystectomy. The authors use the case to present details of the operative procedure of laparoscopic cholecystectomy in small children and infants. Laparoscopic cholecystectomy is the procedure of choice in the management of cholelithiasis in small children and infants, especially those with sickle cell disease.

Urolithiasis in childhood: surgery and lithotripsy

From 1982 through 1993, 174 interventions in 160 infants and children with urolithiasis were performed at our department. There were 101 boys and 59 girls, mean age 8.9 years. The main causes of the interventions were congenital malformations in 62, followed by recurrent urinary tract infections in 29, previous operations in 17, and hypercalciuria in 35 patients. In 17 children, the cause of urolithiasis remained unknown. As a therapeutic option, extracorporeal shock-wave lithotripsy (ESWL) has become available since 1988. The malformations and postoperative conditions are surgically corrected, and the calculi removed in the same act. For post-infectious, idiopathic or hypercalciuric calculi, ESWL has been used in the majority of patients since 1988. Thus, a total of 129 calculi were removed by operation and 47 by ESWL, whereas 18 calculi were endoscopically extracted. There were no complications after either ESWL or open surgery. Calculi in congenital malformations or as a result of operation are still removed by open surgery. In other cases, ESWL is the method of choice.