Treatment of ingrown toenails in the pediatric population

Background/Purpose

Nail avulsion plus chemical matrixectomy (CM) using NaOH as an alternative to surgical matrixectomy (SM) has recently been used in the treatment of ingrown toenails (IGTNs) in adults. No studies exist to dictate the most effective and safe treatment method in the pediatric population.

Methods

A retrospective review of pediatric IGTNs treated at 2 institutions for 6 years was done, looking at presentation, treatment modality, SM vs CM, and outcomes.

Results

Eight hundred forty-eight IGTNs in 518 patients were reviewed with an average age of 12.5 years. Twenty-three percent were felt to be infected at the time of presentation, and 34% were being treated with antibiotics within the preceding week of surgery. Seventy-nine percent of toenails underwent surgical management with the most common procedure being avulsion plus SM (65%), followed by avulsion plus CM (17%), and avulsion alone (14%). The overall recurrence rate after initial surgery was 19.5%. After adjusting for covariates, recurrence was associated with treatment by avulsion alone (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.5-4.7), avulsion plus CM (OR, 0.3; 95% CI, 0.1-0.7), and treatment with antibiotics within the week before surgery (OR, 0.5; 95% CI, 0.3-0.9; P = .017). The overall postoperative infection rate was 6% and was unrelated to presence of preoperative infection, use of antibiotics, or surgical treatment method.

Conclusions

Ingrown toenails present a significant problem to youth and should be addressed in a diligent fashion. Chemical matrixectomy using NaOH is a safe and effective alternative to SM and maybe associated with a lower rate of recurrence, especially when use in conjunction with preoperative antibiotics.     

The role of preoperative mammography in women considering reduction mammoplasty: a single institution review of 207 patients

Background

Standard use of preoperative mammography is controversial in patients considering reduction mammoplasty. The aim of this study was to determine the utility of mammography before breast reduction.

Methods

The authors conducted a single-center, retrospective chart review examining preoperative mammography in reduction mammoplasty candidates.

Results

Between 2001 and 2005, 207 women with recent screening mammography were evaluated for reduction mammoplasty. Thirty-two patients (16%) were found to have abnormal preoperative mammographic results, all of which were false-positives. Previously, reported risk factors including body mass index, decreasing age, previous breast procedure, and lack of comparative mammogram did not predict abnormal mammographic findings. Abnormal imaging results did not influence the decision to proceed with surgery but did have a trend toward delaying surgery.

Conclusions

Mammography before reduction mammoplasty can result in a high number of false-positive results, and surgeons should counsel their patients as to the possibility of subsequent studies.     

Complications associated with postoperative antibiotic prophylaxis after breast surgery

Background

Evidence supports single-dose preoperative antibiotic (ABX) prophylaxis for breast surgery; however, limited data exist regarding the incidence and type of antibiotic complications postoperatively.

Methods

Breast/axillary surgeries between July 2004 and June 2006 were reviewed. Complications were analyzed by antibiotic group: preoperative prophylaxis, postoperative prophylaxis, and therapeutic intent. The Fisher exact test was used to compare complication rates.

Results

A total of 389 patients underwent breast/axillary surgeries during the study period. A total of 363 (93%) patients received ABX: 353 (91%) received a single preoperative dose, 91 (23%) received postoperative ABX prophylaxis, and 76 (201%) received ABX for therapeutic intent. Among patients receiving ABX, 15 (4%) had an ABX-related complication. The ABX-related complication rate was significantly higher among those receiving postoperative prophylaxis (5.5%; 5 of 91) compared with those receiving preoperative ABX alone (0%; 0 of 214) (P = .002).

Conclusions

Drug-related complications were uncommon with preoperative ABX prophylaxis. Considering the potential complications of ABX after breast surgery, the use of postoperative prophylaxis should be reexamined.     

Midterm outcomes of outfracture of the inferior turbinate

Objective

A variety of medical and surgical treatment alternatives exists for the management of inferior turbinate hypertrophy, indicating a lack of consensus on the optimal technique. The purpose of the present study was to evaluate the inferior turbinate objectively by means of radiologic methodology during the early and late periods in patients treated with inferior turbinate outfracture.

Study Design

Case series with planned data collection.

Setting

Tertiary referral center.

Subjects and Methods

Eighty inferior turbinates of 40 patients (28 males, 12 females) who underwent surgery because of septum deviation and inferior turbinate hypertrophy were included in this prospective clinical study. All patients were evaluated by paranasal sinus computed tomography preoperatively and at one and six months postsurgery. The angle and the distance between the inferior turbinate and the lateral wall of the nasal fossa and the area lateral to the inferior turbinate bone were measured on the coronal plane anterior posteriorly at five different anatomic levels.

Results

Statistically significant reductions were noted in the angle and distances in all sections one and six months postoperatively when compared with the preoperative measurements (P < 0.005).

Conclusion

Compared with the preoperative status, those patients who underwent turbinate outfracture procedures displayed a reduction in the angle and the distance between the inferior turbinate bone and the lateral wall of the nasal fossa and the area lateral to the inferior turbinate bone one month following surgery. Ongoing outcomes of this treatment method have been objectively shown.     

Spindle epithelial tumor with thymus-like elements of the thyroid: a multi-institutional case series and review of the literature

Background/Purpose

Spindle epithelial tumor with thymus-like elements (SETTLE) is a rare tumor of the thyroid observed in children and adolescents. We present a case series of 3 patients with SETTLE, focusing on the clinical and pathologic features of this rare tumor.

Methods

Three male patients presented at ages 4.5, 6.5, and 7 years with a right thyroid mass. All were treated by standard hemithyroidectomy. None had evidence of distant metastases at presentation. The diagnosis of SETTLE was confirmed at the time of the initial operation in 2 of the 3 patients.

Results

All patients had uneventful postoperative courses. Two patients remain disease-free 4 and 7 years postresection, respectively. One patient presented 10 years after resection with shortness of breath and hemoptysis secondary to multiple bilateral parenchymal lung metastases. This patient received chemotherapy against the epithelial components of the tumor with a 25% response based on imaging studies.

Conclusion

Spindle epithelial tumor with thymus-like elements is rare tumor that should be suspected if spindle elements are observed in the resected thyroid specimen. Because these patients may present with delayed metastases, follow-up is recommended. However, chemotherapy against specific tumor elements is only marginally effective.     

Nasal septum to columella attachment: A major tip support?

Objective

To determine whether surgical section of attachment of the medial crural footplates to the quadrangular cartilage produces loosening of the nasal tip.

Study Design

Prospective, observational, before-and-after study.

Setting

Tertiary care center.

Subjects and Methods

Hispanic patients undergoing septoplasty who required a transfixion incision were included. A six-month postoperative assessment of the nasal tip support was compared with preoperative values. As measures of the nasal tip support, we included tip recoil test, nasolabial angle, tip rotation angle, nasofacial angle, and the Goode method for determining tip projection.

Results

Twenty-seven patients completed the follow-up, and their results are reported. There were no statistically significant differences after septoplasty in any of the five measurements used to assess the nasal tip support (P > 0.05).

Conclusion

In this preliminary cohort of Hispanic patients, surgical section of the attachment of the medial crural footplates to the quadrangular cartilage does not produce significant changes in nasal tip support.     

Addition of epinephrine to epidural bupivacaine infusions following initiation of labor analgesia with epidural fentanyl

Study Objective

To evaluate the analgesic effects of the addition of epinephrine to a bupivacaine epidural infusion in early labor after a fentanyl bolus, following a lidocaine-epinephrine test dose.

Design

Randomized, double-blinded study.

Setting

Labor suite of a tertiary care hospital.

Patients

60 ASA physical status 1 and 2, laboring, nulliparous women.

Interventions

All laboring women received a 3 mL epidural test dose of 1.5% lidocaine with 1:200,000 epinephrine, followed by a fentanyl 100 μg bolus in 10 mL of diluent volume. Patients were randomized to receive one of two continuous epidural infusions: bupivacaine 0.625 mg/mL at 10 mL/hr (control group) or bupivacaine 0.625 mg/mL with epinephrine 5 μg/mL at 10 mL/hr (epinephrine group).

Measurements

Time to re-dose, pain scores, and side effects were recorded.

Main Results

The mean duration of satisfactory analgesia prior to re-dose was 159 ± 62 min for the control group and 221 ± 111 min for the epinephrine group (P < 0.02). Pain scores were significantly higher in the control group than the epinephrine group at two time periods: 2.5 hours and 4.5 hours (P < 0.04).

Conclusions

The administration of 0.625 mg/mL bupivacaine with epinephrine 5 μg/mL at 10 mL/hr, compared with plain 0.625 mg/mL bupivacaine at 10 mL/hr, provided a longer time to re-dose, decreased pain scores at two time intervals, and had no significant difference in duration of labor or side effects.     

Single or Double Arteries in the Remnant Kidney After Donation: Influence on the Long-Term Outcome of the Donor

Background

A kidney with a single artery is preferred for donation. We wondered how often the donor is left with double or triple arteries, and whether this has any implications for long-term kidney function.

Methods

The consecutive living donors from 1984 to 1988 were reevaluated for kidney function and outcome.

Results

In total, 154 donor nephrectomies were performed with an open anterior technique. Ninety-eight patients were left with a single artery to the remnant kidney and 56 (36%) with more than one. Six individuals were left with 3 arteries. The mean age at donation was 48 ± 12 years and mean age at reevaluation was 68 ± SD 12 years. In the group with a remnant single artery, the mean preoperative serum creatinine level was 87 ± 11 μmol/L, at 6 months it was 127 ± 20 μmol/L, and in 2007 it was 90 ± SD 23 μmol/L. The estimated glomerular filtration rate (GFR) was 67 ± 18 mL/min. Thirty-three percent of donors (19/58) had developed hypertension. Among the group with multiple remnant arteries, the mean preoperative serum creatinine level was 87 ± SD 11 μmol/L, at 6 months it was 131 ± 21 μmol/L, and in 2007 it was 100 ± 45 μmol/L. Estimated GFR was 64 ± 16) mL/min. Twenty-eight percent of the donors (10/36) had developed hypertension.

Conclusions

One third of kidney donors were left with double or triple arteries to the remnant kidney. The 20-year follow-up showed no significant difference in the renal function between the 2 groups.     

Parameters of Doppler Ultrasound at Five Days Posttransplantation as Predictors of Histology and Renal Function at One Year

Introduction

In our center, a Doppler ultrasound (DU) is performed at 5 days after transplantation. The normal upper limit of flow velocity (FV) in the renal artery is 200-250 cm/s. The resistance index (RI) is considered elevated when >0.8. Elevation of the RI can be shown in all the forms of graft dysfunction.

Objective

The objective of this study was to evaluate the capacity of the DU to predict the prognosis of graft function and histological damage at 1 year.

Methods

We examined a retrospective cohort of patients undergoing renal transplantation between January 2004 and May 2007. The renal function was evaluated with serum creatinine measurements and glomerular filtration rate (GFR) estimates by the quadratic Modification of Diet in Renal Disease study equation. The biopsy specimen was evaluated according to the Banff 1997 classification.

Results

The overall average age was 35 years, and 58% of the subjects were men. Eight cases (25.8%) showed abnormal DU. The Delta among those with normal DU was −0.94 versus 0.27 ± 0.39 with abnormal DU (P < .005). There was no significance as far as the biopsy at 1 year.

Conclusions

Renal DU allows physicians to suspect complications at the first posttransplantation year. It shows a tendency to elevated blood pressure, as well as increased deterioration of renal function over the first year.     

Diagnosis and treatment of abdominal cocoon: a report of 24 cases

Background

Abdominal cocoon (AC) is a rare disease characterized by total or partial encasement of the small bowel by a thick, fibrous membrane. Twenty-four cases are reported in this article. Our aim was to investigate the methods of diagnosis and treatment for AC.

Methods

The clinical manifestations, diagnoses, surgical treatments, and follow-up results of 24 cases of AC in the Department of General Surgery of the Third Affiliated Hospital of Sun Yat-sen University between January 1997 and September 2007 were retrospectively analyzed.

Results

Main clinical manifestations were partial or complete intestinal obstruction (87.5%) and abdominal mass (54.2%). Three cases were preoperatively diagnosed by computed axial tomography and 1 case by barium x-ray examination. The other 20 cases were diagnosed by laparotomy. All of the patients underwent surgery. In all cases, we found that part of or the entire small bowel was encapsulated in a dense, white, fibrous, cocoon-like membrane. During surgery, excision of the thick membrane and lysis of adhesions were carefully performed to release the small intestine. Postsurgical recovery in most cases was smooth, and there was no recurrence during a follow-up period of 3 months to 9 years (mean 37 months).

Conclusion

The clinical manifestation of AC is nonspecific; therefore, preoperative diagnosis is difficult. However, its manifestations on barium x-ray and contrast computed axial tomography scan are characteristic, and aggregate analysis of the clinic and radiologic data can increase preoperative diagnosis. The main treatment of AC is surgery, and the overall prognosis of these patients is satisfactory.     

Follow-up of acute osteomyelitis in children: the possible role of PET/CT in selected cases

Background

Magnetic resonance imaging (MRI) and/or scintigraphy are commonly used for follow-up in children after treatment of acute osteomyelitis. Regularly, post-treatment imaging reveals pathological findings even if serum inflammatory parameters and clinical presentation are normal. We analyzed combined positron emission tomography and multislice computed tomography (PET/CT) for this condition.

Methods

Six children received PET/CT after treatment of acute osteomyelitis. Post-treatment MRI had revealed suspicious residual and/or additional findings. All patients had physiological serum infection parameters and no clinical symptoms.

Results

Median patient age was 59.5 months (range, 48-156). No increased 18-Fluor-2-deoxy-D-glucose uptake was observed in 3 patients. In 3 patients, there was minimal activity at the site of infection, which, however, did not reach the presumed range of osteomyelitis. All children were taken off antibiotic medication. No clinical symptoms reoccurred in any of them, and repeatedly controlled serum infection parameters were all normal. Median follow-up was 33 months (range, 4-65).

Conclusions

The PET/CT was superior to MRI in distinguishing between infection and reparative activity within the musculoskeletal system in selected children after acute osteomyelitis. The termination of antibiotic treatment for children after acute osteomyelitis seems justified when laboratory parameters as well as clinical presentation are normal, and PET/CT scan is unsuspicious.     

Reoperative parathyroidectomy in 228 patients during the era of minimal-access surgery and intraoperative parathyroid hormone monitoring

Background

Reoperative parathyroidectomy (R-PTX) in primary hyperparathyroidism (1HPT) has increased failure rates and morbidity. This study evaluated R-PTX during the era of minimal-access PTX with intraoperative parathyroid hormone (IOPTH) monitoring.

Methods

Two thousand sixty-five patients with 1HPT who underwent PTX were assessed for R-PTX. Preoperative studies, operative findings, and outcomes were evaluated.

Results

Two hundred twenty-eight patients underwent 236 R-PTX procedures. Imaging performed included sestamibi (89%), ultrasound (US; 56%), computed axial tomography/magnetic resonance imaging (5%), and selective venous sampling (1%). Sestamibi was more sensitive than US (84% vs 68%). Curative surgery was performed in 89% of patients. IOPTH was 99% sensitive. There was no relationship between cure and the following parameters: preoperative calcium or PTH levels, persistent or recurrent disease, or use of IOPTH. Solitary gland disease and a single previous operation were associated with increased likelihood of cure (P = .06). Hypoparathyroidism was decreased using IOPTH monitoring (2% vs 9%). One patient had recurrent laryngeal nerve palsy.

Conclusions

R-PTX can be performed effectively with minimal complications. IOPTH is an accurate predictor of cure and may decrease the frequency of permanent hypoparathyroidism.     

Immune response deviation and enhanced expression of chemokine receptor CCR4 in TBI patients due to unknown serum factors

Background

Severe brain trauma leads to an activation of the immune system. To this date, neither the exact perturbation of the specific immune reaction induced by the traumatic brain injury (TBI), nor the interactions leading to the infiltration of peripheral immune cells into the brain are fully understood.

Patients and methods

Serum was collected from 17 patients with TBI and a long bone fracture, 24 patients with an isolated long bone fracture and from healthy individuals. The effect of the serum on normal human monocytes and T-lymphocytes was tested in vitro by assessing proliferation and expression of surface markers, chemokine receptors and cytokines.

Results

Serum collected from patients with a TBI and a long bone fracture increased the expression of the chemokine receptor CCR4 in monocytes when compared to patients with an isolated long bone fracture. Extending this comparison to T-lymphocytes, the serum from TBI patients induced lower proliferation rates and decreased expression of the pro-inflammatory cytokine TNF-α, while simultaneously increasing the secretion of immune-modulatory cytokines (IL-4, IL-10 and TGF-β) (p < 0.05).

Conclusion

Patients with a TBI release currently unknown soluble factors into the circulating blood that up regulate expression of chemokine receptor CCR4 in peripheral blood monocytes whilst concurrently inducing expression of immunosuppressive cytokines by activated T-lymphocytes.     

Do patients undergoing parathyroidectomy for primary hyperparathyroidism in San Francisco, CA, and Bursa, Turkey, differ?

Background

To compare the preoperative clinical symptoms and associated conditions and findings in operations in age- and sex-matched patients with primary hyperparathyroidism (PHPT) living in the two different regions of the world to determine whether PHPT differs in various countries.

Methods

Fifty-two patients from Bursa, Turkey were matched with 52 age and sex matched patients from San Francisco, USA. Patients' preoperative symptoms, biochemical and radiologic findings and surgical procedures were documented.

Results

More patients in the American Group (15%) had preoperatively persistant or recurrent hyperparathyroidism, P = 0.016. Serum parathyroid hormone levels were higher in Turkish group (546 ± 75.33 pg/mL) than in American group (146 ± 75.33 pg/mL). More Turkish patients had osteoporosis (P < 0.05). The size of parathyroid adenomas was significantly greater in Turkish patients (25.2 ± 1.18 mm) than in American patients (17.5 ± 1.18 mm), P < 0.001.

Conclusions

Patients with PHPT from Bursa, Turkey have higher plasma parathyroid hormone levels, larger parathyroid adenomas and more severe bone disease than in age and sex matched patients with PHPT in San Francisco.     

Vertebral osteomyelitis after cardiac surgery

Background

Mediastinitis after open-heart surgery is a serious complication that has a decreasing incidence but still a significantly high mortality rate. Back pain may develop during the course of treatment for mediastinitis, and this should suggest vertebral osteomyelitis in the differential diagnosis. Diagnosis of vertebral osteomyelitis may be difficult because of the insidious onset and delayed diagnosis, and treatment may result in serious neurologic compromise and even death of the patient.

Methods

This retrospective study involves 5 patients who had open-heart surgery and mediastinitis that was further complicated by vertebral osteomyelitis. Average delay in diagnosis was 18 days after the onset of symptoms. Magnetic resonance imaging was the most helpful tool for diagnosis. Methicilline-resistant Staphylococcus aureus was identified as the responsible microorganism in all patients. Neurologic compromise occured (one paraplegia and one paraparesia) in 2 patients during medical treatment.

Results

Along with the medical treatment, all patients were surgically treated due to either one or more of the following reasons: unresolving symptoms, sudden neurologic compromise, or impaired spinal column stability despite appropriate conservative treatment. One patient died 10 days postoperatively. The mean follow-up period for the remaining 4 patients was 47 (12 to 95) months. Complete recovery was achieved, and they were able to return to their routine daily activities.

Conclusions

Vertebral osteomyelitis should be borne in mind when a patient develops back pain during the course of mediastinitis. Suspicion, early diagnosis with appropriate imaging, and proper treatment are crucial to prevent catastrophic complications.     

Cancer-specific and other-cause mortality after radical prostatectomy versus observation in patients with prostate cancer: competing-risks analysis of a large North American population-based cohort

Background

Initial treatment options for low-risk clinically localized prostate cancer (PCa) include radical prostatectomy (RP) or observation.

Objective

To examine cancer-specific mortality (CSM) after accounting for other-cause mortality (OCM) in PCa patients treated with either RP or observation.

Design, setting, and participants

Using the Surveillance Epidemiology and End Results Medicare-linked database, a total of 44 694 patients ≥65 yr with localized (T1/2) PCa were identified (1992-2005).

Intervention

RP and observation.

Measurements

Propensity-score matching was used to adjust for potential selection biases associated with treatment type. The matched cohort was randomly divided into the development and validation sets. Competing-risks regression models were fitted and a competing-risks nomogram was developed and externally validated.

Results and limitations

Overall, 22 244 (49.8%) patients were treated with RP versus 22450 (50.2%) with observation. Propensity score-matched analyses derived 11 669 matched pairs. In the development cohort, the 10-yr CSM rate was 2.8% (2.3-3.5%) for RP versus 5.8% (5.0-6.6%) for observation (absolute risk reduction: 3.0%; relative risk reduction: 0.5%; p < 0.001). In multivariable analyses, the CSM hazard ratio for RP was 0.48 (0.38-0.59) relative to observation (p < 0.001). The competing-risks nomogram discrimination was 73% and 69% for prediction of CSM and OCM, respectively, in external validation. The nature of observational data may have introduced a selection bias.

Conclusions

On average RP reduces the risk of CSM by half in patients aged ≥65 yr, relative to observation. The individualized protective effect of RP relative to observation may be quantified with our nomogram.     

A 6-Month, Multicenter, Single-Arm Pilot Study to Evaluate the Efficacy and Safety of Generic Tacrolimus (TacroBell) After Primary Renal Transplantation

Objective

Tacrolimus has been shown to be an important immunosuppressive agent in organ and bone marrow transplantation. Previously, we reported that there were no statistically significant differences between the pharmacokinetic parameters of the oral formulation of generic tacrolimus (TacroBell) and the conventional formulation (Prograf). This study was designed to evaluate the efficacy and safety of oral capsules of TacroBell in de novo renal transplantation.

Methods

Ninety-six renal transplant recipients from 9 transplantation centers in South Korea were enrolled between November 2005 and July 2007. De novo renal recipients ranged from 19-65 years old. Ninety-four patients who underwent renal transplantation were administered study drug at least one time in the intent-to-treat (ITT) analysis. This phase 4 clinical trial was a 26-week, open-label, noncomparative, multicenter study.

Results

An acute rejection episode developed in 10/94 recipients (10.6%, 95% confidence interval, 4.4%-16.9%). There were no patient deaths during the study. The 6-month graft survival rate was 96.8%.

Conclusion

Based on this study, treatment with TacroBell is considered to be efficient and safe after primary renal transplantation.     

Bone health in patients with cloacal exstrophy and persistent cloaca after bladder augmentation

Purpose

In this study, the prevalence of osteoporosis was evaluated in patients operated on for cloacal exstrophy or persistent cloaca and who had undergone bladder augmentation.

Methods

Seven patients operated on because of cloacal exstrophy and 3 patients operated on because of persistent cloaca were evaluated. Patients were clinically assessed. Areal bone mineral density for the lumbar spine (L1-L4), femoral neck, and whole body was measured with dual-energy x-ray absorptiometry. Acid-base balance, plasma 25-hydroxyvitamin D (vitamin D), and gonadal function were determined and correlated with dual-energy x-ray absorptiometry results.

Results

The patients were small in height (median, −2.2 SD). According to areal bone mineral density measurements, 40% of the patients had significantly reduced BMD. When the values were adjusted for patient size, only 1 patient had slightly reduced bone mass. Half of the patients had low vitamin D values. The height-corrected bone mineral content values showed a positive correlation with vitamin D values (P = .0072) but were not different in patients with and without hypogonadism (P = .33).

Conclusions

Patients with cloacal exstrophy or complicated cloaca have many risk factors for osteoporosis. However, this study showed good overall bone health in affected adolescents.     

The influence of various registration procedures upon surgical accuracy during navigated controlled petrous bone surgery

Objective

The goal of this study was to investigate the dependence of surgical accuracy with a navigated controlled (NC) drill on selected registration procedures.

Study design

The target registration error of the instrument and the maximum proximity to a typical high-risk structure (facial nerve) were determined within an artificial petrous bone.

Setting

The studies took place in two groups: group 1, navigation bow with six integrated markers and attachment at the upper jaw, and group 2, landmark registration with four titanium microscrews. Measurement of the target registration error took place at three targets (3 titanium screws) with 20 repeated registration procedures via evaluation of the deviation between a target and the indicated position in the navigation data.

Subjects and Methods

For measurement of the conversion accuracy of the planned cavity, 20 petrous bone models were milled by inexperienced test subjects. The evaluation of 20 cavities was conducted via a microscope by five jurors.

Results

Registration accuracy showed a maximum deviation between the actual position achieved and the computed position in the navigation system of 1.73 mm in group 1 and 0.93 mm in group 2. In group 1, the nerve in five of 20 cases was damaged, and a maximum penetration into the nerve of 1.5 mm (0.25 mm SD; milled beyond) was measured. In group 2, the facial nerve was not damaged at all, and a maximum deviation of 0.5 mm (0.63 mm SD; stopped before) was measured.

Conclusion

The results for registration and conversion accuracy are significantly better for the landmark-based registration than with the registration of the patient model with registration bow on the upper jaw.