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PubMed1994

Use of decision analysis in planning a management strategy for the stage N0 neck.

OBJECTIVE: There are three major strategies in the treatment of patients with a stage N0 neck with squamous cell cancer of the head and neck: elective neck dissection, elective neck irradiation, and observation. Each has appropriate salvage strategies in the event of local recurrence. We used decision analysis to determine the optimal strategy for neck treatment as a function of the probability of occult cervical metastasis. DATA SOURCES: We used the bibliographies of current articles and books to access clinical studies of patients with stage N0 neck cancer. STUDY SELECTION: Studies that included large numbers of patients and contained a minimum 2-year follow-up, with results analyzed in terms of outcome as a function of stage of neck disease, were included. DATA EXTRACTION: Specific data points were extracted from the studies independently by multiple observers, and mean values were used in the decision analysis. DATA SYNTHESIS: A decision tree was constructed with use of a computer model to compare the three management strategies. Probabilities of each of the possible events depicted in the trees were inserted into the tree structure. These probabilities were gleaned from the literature as described above. A sensitivity analysis was performed to determine the optimal threshold for treatment of the neck. CONCLUSION: A patient with primary squamous cell carcinoma of the head and neck and stage N0 neck status should be observed if the probability of occult cervical metastasis is less than 20%. If the probability is greater than 20%, treatment of the neck is warranted. The treatment plan should ideally involve a single modality of therapy; both neck dissection and radiation therapy are quite efficacious in the clinical context, and the decision of which one to employ should be driven by the treatment of the primary lesion. Decision analysis is useful in complex clinical situations.

Carcinoma, Squamous Cell↗
PubMed2006

Parotid metastasis--an independent prognostic factor for head and neck cutaneous squamous cell carcinoma.

BACKGROUND: Metastatic parotid cutaneous squamous cell carcinoma (SCC) is the most common parotid gland malignancy in New Zealand and Australia. The current AJCC TNM staging system does not account for the extent of nodal metastasis. A staging system that separates parotid (P stage) from neck disease (N stage) has been proposed recently. AIM: To review the outcome of patients with metastatic head and neck cutaneous SCC treated at our multidisciplinary Head and Neck Service using the proposed staging system. METHOD: Consecutive patients were culled from our Head and Neck/Skull Base Database, 1990-2004. These patients were restaged according to the proposed staging system: P stage: P0 = no disease in the parotid (i.e., neck disease only); P1 = metastatic node < or = 3 cm; P2=metastatic node > 3 cm and < or =6 cm, or multiple nodes; and P3 = metastatic node > 6 cm, or disease involving the facial nerve or skull base. N stage: N0=no disease in the neck (i.e., parotid disease only); N1 = single ipsilateral metastatic node < or = 3 cm; and N2 = multiple metastatic nodes, or any node > 3 cm, or contralateral neck involvement. Loco-regional recurrence and disease-specific survival were calculated using the Kaplan-Meier method and comparison of graphs made with the log-rank test. Multivariate analysis using the Cox regression model was carried out to assess the impact of various parameters. RESULTS: Sixty-seven patients with metastatic head and neck cutaneous SCC were identified. Thirty-seven patients had parotid metastasis (of whom 13 also had neck disease) while 21 had neck metastasis alone. Nine patients had dermal or soft tissue metastasis. These nine patients were excluded from this series, and data analysis was carried out on the remaining 58 (46 men, 12 women, mean age 71 years) patients. Sixty-seven percent of the patients underwent post-operative adjuvant radiotherapy. The five-year disease-specific survival rate was 54%. Among 56 patients followed up to disease recurrence or for a minimum period of 18 months, the loco-regional recurrence rate was 52%. The presence of parotid disease was an independent prognostic factor on survival (p < 0.01), and P3 fared significantly worse than P1 and P2. Those patients who had both parotid and neck disease fared worse than those who had parotid or neck disease alone (p = 0.01). N2 had a significantly poorer outcome compared with N1 (p < 0.01). Immunosuppression (p = 0.01) and a positive surgical margin (p < 0.01) were significant adverse prognostic factors for survival. Adjuvant radiotherapy, extracapsular spread, and perineural and vascular invasion did not influence survival. Our study demonstrates that the extent of parotid disease is an independent prognostic factor for metastatic head and neck cutaneous SCC.

Aged↗
PubMed2004

Management of patients with squamous cell carcinoma of the lower lip and N0-neck.

AIM: For lower lip carcinoma, an incidence of 15% of cervical lymph node metastasis at presentation is generally accepted. This is an argument in favour of an expectant approach. The purpose of this study was to compare the results of the different approaches to the clinically negative neck: prophylactic neck dissection, prophylactic neck irradiation and follow-up. MATERIAL AND METHOD: The retrospective study included 200 patients with lower lip carcinoma. The following data were evaluated: (1) the incidence of cervical lymph node metastasis in patients with a clinically negative neck; and (2) pathological confirmation of cervical lymph node metastasis. RESULTS: In the group undergoing prophylactic neck dissection, lymph node metastasis was found microscopically in 20% of the cases. More than half of the patients receiving prophylactic radiotherapy developed bulky neck lymph node metastases. Out of the patients attending the 2-year follow-up 64% developed a clinically positive neck. Cervical lymph node metastases in these patients was proven microscopically in 88% of cases. CONCLUSION: The high incidence of a clinically positive neck, along with the high incidence of neck node metastasis found in neck dissection specimens suggest that elective neck dissection is the treatment of choice for the neck in patients with lower lip carcinoma.

Carcinoma, Squamous Cell↗
PubMed2004

Cervical range of motion associations with subclinical neck pain.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To investigate associations between subclinical neck pain/discomfort, and range of motion and physical dimensions of the cervicothoracic spine. SUMMARY OF BACKGROUND DATA: Despite the high prevalence of neck problems, few studies are available indicating any physical associations with the development of neck pain, or information regarding early signs of pathology from neck pain for subjects not in treatment. METHODS: Forty healthy volunteers, between 19 and 42 years of age (mean age 28 years), were recruited. The dimensions of the cervicothoracic spine measured were as follows: spinal posture, active cervical range of motion, and segment length of the neck. All measurements were taken twice from each subject by different testers, on the same occasion. Cervical muscle endurance was measured by a modified Biering-Sørensen Test. Finally, subjects were questioned about any recurrent neck pain/discomfort. RESULTS: Fourteen subjects reported experiencing low-level neck pain/discomfort on a recurrent basis. Neck muscle endurance time (F1,38 = 6.75, P = 0.01) and left rotation end-of-range (F1,38 = 4.56, P = 0.04) were found to be significantly lower for subjects with neck pain. Extension end-of-range showed a group-specific change at retest, increasing for subjects without pain, but decreasing for those with neck pain (F1,38 = 4.67, P = 0.04). This same group had a greater range of retraction than the asymptomatic group (F1,38 = 4.56, P = 0.04). Subjects overall, irrespective of pain classification, demonstrated greater left rotation than right rotation (F1,38 = 4.34, P = 0.04) and also showed reduced side flexion on the left (F1,38 = 5.10, P = 0.03) and right (F1,38 = 5.27, P = 0.03) with repeated measurement. CONCLUSIONS: Between-groups differences were observed as lower neck muscle endurance time, reduced left rotation, relatively reduced extension at second test, but greater range of retraction, when the subclinical and normal groups were compared. These data suggest that there are early range changes associated with the development of neck pain.

Adult↗
PubMed2006

Level V lymph node dissection in oral and oropharyngeal carcinoma patients with clinically node-positive neck: is it absolutely necessary?

OBJECTIVES: Postoperative shoulder dysfunction has been significantly associated with any dissection of level V secondary to traction or with ischemic injury to the spinal accessory nerve. The aim of this study was to determine whether the dissection of level V lymph node pads is absolutely necessary in therapeutic neck dissection as a treatment for oral and oropharyngeal squamous cell carcinoma (OOSCC) patients with clinically N+ neck. STUDY DESIGN: Retrospective chart review. METHODS: We performed a retrospective analysis of 93 OOSCC patients who underwent surgical treatment of the primary lesion along with a simultaneous comprehensive neck dissection from January 1992 to December 2003. Of these, only one patient had a clinically positive neck node at level V. During the neck dissection, the contents of the level V lymph nodes were dissected, labeled, and processed separately from the remainder of the major neck dissection specimen. We studied the incidence of pathologic metastasis to level V lymph nodes. In addition, we also evaluated several potential risk factors for metastatic disease in the level V lymph nodes such as sex, age, T stage, N stage, histologic grade, and presence of other positive lymph nodes. RESULTS: A total of 96 comprehensive neck dissections were performed in this series. The prevalence of metastases in the level V lymph nodes was 5% (5 of 93) in ipsilateral and 0% (0 of 3) in contralateral necks. One case with clinically positive node at level V had a pathologic positive node in level II, III, IV, and V. Occult metastasis rate of ipsilateral level V was 4% (4 of 92). There was a statistically significant association between level V metastases and a positive N stage above N2b (P=.01). The presence of metastasis in other multiple neck levels, particularly the combined neck levels II, III, and IV, also have a statistically significant association with level V metastasis (P=.023). CONCLUSION: Level V lymph node pads may be preserved in modified neck dissections on OOSCC patients with clinically N+ neck below the nodal stage N2a.

Adult↗
PubMed1981

The eleventh nerve in radical neck surgery.

The greatest morbidity associated with the radical neck dissection has been the "shoulder syndrome" due to the sacrifice of the spinal accessory nerve. Despite the fact that the XIth nerve can be spared by a careful dissection of the postcervical triangle, to do so remains a controversial issue. The 125 radical neck dissections performed at the University of Wisconsin Clinical Science Center from 1970 through 1975 were carefully evaluated to determine the incidence of recurrent tumor in the operated-on neck. In 60 cases the spinal accessory nerve was resected with the neck specimen, and in 65 cases the nerve was preserved. A second study was then undertaken involving 245 neck dissections performed from 1975-1978 in the Wisconsin Head and neck Cancer Control Network Hospitals. In 69 instances the spinal accessory nerve was spared. The total number of neck dissections (370 cases) from both studies were analyzed. The overall rate for recurrent tumor in the neck with the classical neck dissection was 12%. When the spinal accessory nerve was spared, the recurrent rate was 6%. On the basis of these observations we propose that the classical neck dissection can be modified to preserve the spinal accessory nerve without jeopardizing the chances for a cure in elective neck dissections and selected therapeutic neck dissections.

Accessory Nerve↗
PubMed1984

Functional neck dissection: an evaluation and review of 843 cases.

After briefly reviewing the principles, indications, and merits of functional neck dissection, the results of 1200 neck dissections performed on 843 patients in the period 1961-1979 are presented. They compare very favorably with those reported for classic (radical) neck dissection by other leading authors; however, a retrospective analysis of data derived from material of different origin is hardly possible and has a disputable value. Therefore, we decided to compare our data on functional neck dissections (FND) with those of classic neck dissections (CND) performed by the same surgical team at the same clinic in the period 1948-1960. The clinical material was largely the same in both cases, and the data were collected and analyzed using the same criteria. In both series, neck dissections were divided into elective and curative. It could be demonstrated that the number of neck recurrences observed in the dissected necks is the same for FND and CND in curative dissections, while it is considerably lower for FND in elective neck dissections. This of course does not prove improved radicality in FND, but only proves that a systematic bilateral elective neck dissection in N0 cases affords improved cancerological safety. This radical bilateral approach to regional lymph nodes is made possible routinely by FND which avoids the problems of unnecessary mutilation. The figures produced speak in favor of a wider adoption of FND especially for expanding the indications to elective treatment of regional lymph nodes in cancer of the head and neck. Elective neck dissection is made practically harmless by this newer technique and averts the dreadful appearance of late metastases in N0 cases.

Head and Neck Neoplasms↗
PubMed2005

Clinical versus computed tomography evaluation in the diagnosis and management of deep neck infection.

CONTEXT: Deep neck infections have high potential for severe complications and even death, if not properly managed. The difference between clinical and computed tomography findings may demonstrate that clinical evaluation alone underestimates disease extent, which may lead to conservative treatment with worse prognosis. OBJECTIVE: To compare clinical and computed tomography findings from neck spaces affected by deep neck infections and to determine the main clinical and radiological features associated with these. TYPE OF STUDY: Non-randomized retrospective study. SETTING: Department of Otolaryngology and Head and Neck, Universidade Estadual de Campinas. METHODS: Medical charts of 65 patients with deep neck infections were evaluated. Age, gender, clinical complaints, physical findings, computed tomography scan and x-ray imaging, microbiology, treatment and outcome were analyzed. All clinical signs and symptoms were evaluated and stratified in order of frequency. The frequency of neck space involvement in such infections was also assessed from the clinical and tomographic evaluation. All clinical and computed tomography findings were compared with surgical observation. RESULTS: The most frequent clinical findings were neck swelling, local pain, erythema and locally increased temperature. Physical evaluation showed that the most affected site was the submandibular triangle (49.2% of cases). However, computed tomography showed this to be the lateropharyngeal space (65% of cases) and that more than one deep cervical space was compromised in 90% of cases, as demonstrated by the extent of swelling and increased contrast signs in soft tissue. DISCUSSION: The most frequent clinical symptoms of deep cervical infections were cervical pain, increased cervical volume and fever. The important signs seen via computed tomography were increased contrast in soft neck tissues and swelling. Such examination is the most important method for correct evaluation of cervical spaces involved in infection, and thus for correct surgical drainage. CONCLUSIONS: The most frequent clinical findings were cervical mass, neck pain, local erythema and locally increased temperature. Computed tomography demonstrated that the lateropharyngeal space was the most affected neck space. More than one deep neck space was compromised in 90% of cases. Clinical evaluation underestimated the extent of deep neck infection in 70% of patients.

Abscess↗
PubMed1991

Penetrating wounds of the neck.

The management of penetrating wounds of the neck provides several decision-making steps that remain controversial. The two basic concepts of management include the idea that all wounds deep to the platysma should be explored and (the more conservative concept) that selective neck exploration should be based on a battery of tests to identify traumatic injuries. The areas of agreement within these two schools of thought include exploration of wounds with obvious injury, exploration of wounds in which patients cannot be stabilized satisfactorily for further testing, and the idea that all patients with wounds deep to the platysma should be admitted to the hospital. The remaining issues, including the need for angiography, barium swallow, or endoscopy, still are contested. Mandatory exploration of neck wounds became popular during World War II. The weapons used, the lack of accurate testing, and delays in treatment caused by transport problems played significant roles in the development of this policy. Proponents of mandatory exploration of neck wounds contend that delays in treatment result in increased mortality rates. Also delays caused by lengthy diagnostic testing have resulted in rapid exsanguination of patients who might otherwise have been surgically salvageable. These factors, along with the potential for undetected injuries and the associated complications (including false aneurysms and mediastinitis) favor mandatory exploration. Advocates of routine neck explorations also note the low morbidity rates associated with a neck exploration. Reported rates of negative exploration are high, however, approaching 45%, and mortality rates vary from 2% to 9%. Selective neck exploration has gained popularity in some centers because of the lower negative exploration rates associated with this treatment, while comparable mortality rates are achieved. May found a negative exploration rate of 12% in his series of selective neck explorations and a mortality rate of approximately 3%. Furthermore, Noyes found that the hospital stay for patients with selective observation management not requiring a neck exploration was 2.8 days, compared with 4.2 days for patients with mandatory but negative neck explorations. A summary of diagnostic techniques and their indications in selecting patients with penetrating neck wounds for surgery is presented in Table 5. It has become apparent that both selective and mandatory explorations of neck wounds play important roles in treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1997

[Spinal accessory nerve and lymphatic neck dissection].

Radical neck dissection was the golden standard of treatment for cervical nodes in head and neck tumors. From the seventies, the preservation of the spinal accessory nerve has become increasingly popular in order to improve the functional result of the neck dissections. The aim of this study was to assess the degree of functional disability associated with each type of neck dissection and the value of anatomical references for dissection of the spinal accessory nerve. One hundred twenty seven patients were evaluated 1 month and 1 year after radical, functional or supraomohyoid neck dissection with a questionnaire and a physical examination. Anatomical measurements of the spinal accessory nerve were performed in 20 patients. We found considerable or severe shoulder dysfunction in 7%, 34% and 51% respectively of patients in whom supraomohyoid, functional and radical neck dissections were performed. Furthermore 49% of patients having undergone a radical neck dissection had little or no symptoms. Sacrifice of the spinal accessory nerve in radical neck dissection may lead to shoulder dysfunction. A functional disability may also be associated, although in a less extent, with any neck dissection in which the spinal accessory nerve is dissected and placed in traction. There is a large variation in the degree of functional disability and pain in patients with similar neck dissections. The course of the spinal accessory nerve in the neck makes it particularly vulnerable to injury during the dissection near the sternocleidomastoid muscle and in the posterior cervical triangle.

Accessory Nerve↗
PubMed2001

The role of neck dissection after chemoradiotherapy for oropharyngeal cancer with advanced nodal disease.

OBJECTIVE: To analyze and compare the effectiveness of sequential platinum-based chemotherapy and radiotherapy with and without selective neck dissection in patients with N2a and greater stage node-positive squamous cell carcinoma of the oropharynx. DESIGN: Nonrandomized controlled trial. SETTING: Tertiary referral center. PATIENTS: Sixty-six patients with squamous cell carcinoma of the oropharynx staged N2a or greater. INTERVENTIONS: Platinum-based induction chemotherapy followed by definitive radiation therapy; and selective neck dissections 6 to 10 weeks following the completion of radiation therapy in patients with radiographic evidence suggesting residual neck disease. MAIN OUTCOME MEASURES: Locoregional recurrence and disease-free survival. RESULTS: Of 66 patients, 24 (36%) had complete responses in the primary local tumor (oropharynx) and regional disease (neck nodes), as assessed clinically and radiographically. These patients had lower rates of locoregional recurrence than did patients showing no or partial responses, but the differences were not significant (P>.05). Of 18 patients undergoing neck dissection, 10 (56%) had pathological evidence of residual tumor. Patients showing a complete response of regional and neck disease had significantly improved disease-specific and overall survival (P = .01 for both) compared with patients showing no or partial responses of their neck disease. Patients with no or partial responses who underwent neck dissections had significantly improved overall survival compared with similar patients who did not undergo neck dissections (P = .002). CONCLUSIONS: Even in patients with bulky nodal disease, a complete response in the neck to sequential chemotherapy and radiotherapy may indicate that neck surgery is not necessary for good locoregional control and improved disease-free survival. Neck dissection is recommended for patients with no or partial radiographic responses.

Adult↗
PubMed2003

Regional tumor recurrence after supraomohyoid neck dissection.

OBJECTIVE: To evaluate the recurrence of lymphatic metastases in patients with squamous cell carcinoma of the oral cavity treated with supraomohyoid neck dissection with and without postoperative radiotherapy. DESIGN: A nonrandomized retrospective study. SETTING: Department of Otolaryngology and Head and Neck, State University of Campinas, São Paulo, Brazil, a tertiary referral center. PATIENTS: Thirty-two patients with squamous cell carcinoma of the oral cavity without previous treatment and a minimum follow-up period of 2 years were studied. There were 36 supraomohyoid neck dissections, of which 31 were elective (clinically negative nodes) and 5 therapeutic (clinically positive nodes). INTERVENTION: Resection of the primary tumor and supraomohyoid neck dissection, with or without postoperative radiotherapy. MAIN OUTCOME MEASURES: Evaluation of neck tumor recurrence according to clinical and histopathological findings in the neck and use of postoperative radiotherapy. RESULTS: The overall recurrence rate was 6% (2 patients). Recurrences were seen in 1 clinically negative neck (3%) and 1 clinically positive neck (20%). The presence of clinically or histopathologically positive nodes, number of positive nodes, and use of adjuvant radiotherapy did not influence the rate of neck tumor recurrence with a statistically significant difference. CONCLUSIONS: Neck tumor recurrence in procedures with clinically positive nodes was 6.3 times greater than in those with clinically negative nodes. There was no difference in regional recurrence of histopathologically positive node necks with or without the addition of postoperative radiotherapy. Neck tumor recurrence was not statistically influenced by clinically and histopathologically positive nodes, multiple positive nodes, and use of postoperative radiotherapy.

Carcinoma, Squamous Cell↗
PubMed1997

Comparison of ultrasound-fine needle aspiration and computed tomography in patients undergoing elective neck dissection.

BACKGROUND: Ultrasound of the neck with fine needle aspiration (US-FNA) of suspicious lymph nodes has potential advantages over other radiologic techniques as a screening method for the NO neck in head and neck cancer. METHODS: Twenty-five patients with head and neck cancer who underwent both US of the neck with FNA of any suspicious lymph nodes and neck computed tomography (CT) prior to elective neck dissection were studied. The majority of patients had squamous cell carcinoma (SCC) of the upper aerodigestive tract. Histopathologic results of the neck specimens were compared with each screening technique (palpation, US, US-FNA, CT). RESULTS: Computed tomography (87.9%) and US-FNA (84.9%) had similar overall accuracy in terms of screening the NO neck in our study and were superior to palpation (69.7%) and US alone (72.7%). Specificity was 100% for both CT and US-FNA, with a sensitivity of 60% for CT and 50% for US-FNA. Ultrasound-FNA and CT showed false-negative examinations on virtually the same cases. CONCLUSIONS: Overall, US-FNA was comparable to CT in screening the NO neck in our study. The choice of which modality to employ for imaging the clinically negative neck depends on a number of factors, including the location and clinical extent of the primary tumor as well as the experience and preference of the head and neck surgeon and radiologist.

Biopsy, Needle↗
PubMed2006

Implications for clinical staging of metastatic cutaneous squamous carcinoma of the head and neck based on a multicenter study of treatment outcomes.

BACKGROUND: Cutaneous squamous cell carcinoma (SCC) of the head and neck is a common cancer that has the potential to metastasize to lymph nodes in the parotid gland and neck. Previous studies have highlighted limitations with the current TNM staging system for metastatic skin carcinoma. The aim of this study was to test a new staging system that may provide better discrimination between patient groups. METHODS: A retrospective multicenter study was conducted on 322 patients from three Australian and three North American institutions. All had metastatic cutaneous SCC involving the parotid gland and/or neck and all were treated for cure with a minimum followup time of 2 years. These patients were restaged using a newly proposed system that separated parotid disease (P stage) from neck disease (N stage) and included subgroups of P and N stage. Metastases involved the parotid in 260 patients (149 P1; 78 P2; 33 P3) and 43 of these had clinical neck disease also (22 N1; 21 N2). Neck metastases alone occurred in 62 patients (26 N1; 36 N2). Ninety percent of patients were treated surgically and 267 of 322 received radiotherapy. RESULTS: Neck nodes were pathologically involved in 32% of patients with parotid metastases. Disease recurred in 105 (33%) of the 322 patients, involving the parotid in 42, neck in 33, and distant sites in 30. Parotid recurrence did not vary significantly with P stage. Disease-specific survival was 74% at 5 years. Survival was significantly worse for patients with advanced P stage: 69% survival at 5 years compared with 82% for those with early P stage (P = 0.02) and for those with both parotid and neck node involvement pathologically: 61% survival compared with 79% for those with parotid disease alone (P = 0.027). Both univariate and multivariate analysis confirmed these findings. Clinical neck involvement among patients with parotid metastases did not significantly worsen survival (P = 0.1). CONCLUSIONS: This study, which included a mixed cohort of patients from six different institutions, provides further information about the clinical behavior of metastatic cutaneous SCC of the head and neck. The hypothesis that separation of parotid and neck disease in a new staging system is supported by the results. The benefit of having subgroups of P and N stage is uncertain, but it is likely to identify patients with unfavorable characteristics that may benefit from further research.

Carcinoma, Squamous Cell↗
PubMed1998

Structural design of the femoral neck in primates.

This study investigates the structural design of the femoral neck with respect to phylogeny, locomotor behavior, and body size in a large comparative sample of primates. Since a bone's strength is determined by the amount and arrangement of its constituent material, the amount and distribution of bone in the femoral neck are the focus of the present study. Two types of data were collected. First, the total distribution of bone across the femoral neck (perpendicular to the femoral neck axis) was examined using image analysis techniques. The distribution of both cortical and trabecular bone are included in this analysis. Secondly, the external dimensions of the femoral neck and the thickness of the superior and inferior cortices, measured from radiographs, were used to calculate femoral neck cross-sectional properties (cortical area and second moment of area). These data were input into a simplified cantilevered beam model that incorporates femoral neck-shaft angle and femoral neck length and is used to predict stress under one unit body mass of loading on the femoral head. The patterns of bone distribution in the femoral neck between taxa are broadly similar for the analysis that includes both trabecular and cortical bone and that which includes only cortical bone. In all cases, there tends to be more bone on the inferior aspect of the femoral neck compared to the superior aspect. However, the non-human hominoids and New World monkeys (e.g., Ateles and Alouatta) have a more even distribution of bone across the femoral neck and have thicker superior cortices relative to inferior cortices compared to the rest of the comparative sample, including humans. It is proposed that the more equal distributional pattern in the non-human hominoids and atelines reflects less stereotypical, more generalized loading orientations. Differences between species in overall strength of the femoral neck are a function of both body size and locomotor mode.

Adult↗
PubMed2000

Cortical bone distribution in the femoral neck of strepsirhine primates.

The thickness of the inferior and superior cortices of the femoral neck was measured on X-rays of 181 strepsirhine primate femora representing 24 species. Neck length, neck depth and neck-shaft angle were also measured. The strength of the femoral neck in frontal bending was estimated by modeling the neck as a hollow cylinder, with neck depth as the outer diameter and cortical thickness representing the superior and inferior shell dimensions. Results indicate that the inferior cortex is always thicker than the superior cortex. The ratio of superior to inferior cortical thickness is highly variable but distinguishes two of the three locomotor groups in the sample. Vertical clingers and leapers have higher ratios (i.e., a more even distribution of cortical bone) than quadrupeds. The slow climbers tend to have the lowest ratios, although they do not differ significantly from the leapers and quadrupeds. These results do not confirm prior theoretical expectations and reported data for anthropoid primates that link greater asymmetry of the cortical shell to more stereotypical hip excursions. The ratio of superior to inferior cortical thickness is unrelated to body mass, femoral neck length, and neck-shaft angle, calling into question whether the short neck of strepsirhine primates acts as a cantilever beam in bending. On the other hand, the estimated section moduli are highly correlated with body mass and neck length, a correlation that is driven primarily by body mass. In conclusion, we believe that an alternative interpretation to the cantilever beam model is needed to explain the asymmetry in bone distribution in the femoral neck, at least in strepsirhine primates (e.g., a thicker inferior cortex is required to reinforce the strongly curved inferior surface). As in prior studies of cross-sectional geometry of long bones, we found slightly positive allometry of cortical dimensions with body mass.

Animals↗
PubMed1998

Short-term changes in neck muscle and eye movement responses following unilateral vestibular neurectomy in the cat.

The purpose of this study was to investigate changes in neck muscle and eye movement responses during the early stages of vestibular compensation (first 3 weeks after unilateral vestibular neurectomy, UVN). Electromyographic (EMG) activity from antagonist neck extensor (splenius capitis) and flexor (longus capitis) muscles and eye movements were recorded during sinusoidal visual and/or otolith vertical linear stimulations in the 0.05-1 Hz frequency range (corresponding acceleration range 0.003-1.16 g) in the head-fixed alert cat. Preoperative EMG activity from the splenius and longus capitis muscles showed a pattern of alternate activation of the antagonist neck muscles in all the cats. After UVN, two motor strategies were observed. For three of the seven cats, the temporal activation of the individual neck muscles was the same as that recorded before UVN. For the other four cats, UVN resulted in a pattern of coactivation of the flexor and extensor neck muscles because of a phase change of the splenius capitis. In both subgroups, the response patterns of the antagonist neck muscles were consistent for each cat independently of the experimental conditions, throughout the 3 weeks of testing. Cats displaying alternate activation of antagonist neck muscles showed an enhanced gain of the visually induced neck responses, particularly in the high range of stimulus frequency, and a gain decrease in the otolith-induced neck responses at the lowest frequency (0.25 Hz) only. By contrast, for cats with neck muscle coactivation, the gain of the visually induced neck responses was basically unaffected relative to preoperative values, whereas otolith-induced neck responses were considerably decreased in the whole range of stimulation. As concerns oculomotor responses, results in the two subgroups of cats were similar. The optokinetic responses were not affected by the vestibular lesion. On the contrary, otolith-induced eye responses showed a gain reduction and a phase lead. Deficits and short-term changes after UVN of otolith- and semicircular canal-evoked collic and ocular responses are compared.

Animals↗
PubMed2002

Complications of neck dissection for thyroid cancer.

Prophylactic and therapeutic neck dissections are used to control or eliminate local nodal disease in patients with thyroid cancer. The purpose of this study was to evaluate the results and complications of neck dissection. From 1992 to 1999 a series of 115 consecutive neck dissections were performed in 74 patients (32 men, 42 women; mean age 48 years) with thyroid cancer and nodal metastases. Operations included central compartment, lateral modified, and suprahyoid dissection with and without total or completion thyroidectomy. Sixty-four percent of the patients had papillary, 4% follicular, and 32% medullary thyroid cancer. Complications included transient hypocalcemia (23%) defined by a postoperative serum calcium level of <2.0 mmol/L (8.0 mg/dl), one neck hematoma (0.9%), and one cardiac death (0.9%). There were no permanent recurrent nerve palsies. Hypocalcemia occurred more frequently when neck dissection was combined with total thyroidectomy than without it (p <0.005). In this group, the incidence of hypocalcemia was higher after central, than lateral, neck dissection. When neck dissection was performed without thyroidectomy, there was no difference in the rates of hypocalcemia between central, lateral, or central with lateral neck dissection (p = NS). Hypocalcemia did not increase with repeated neck dissections (p = NS). Permanent hypoparathyroidism occurred in 0.9%. There were no complications after suprahyoid dissection. The median duration of hospitalization was 1 day. Therapeutic neck dissection or repeated neck dissection can be performed relatively safely in patients with thyroid cancer. Hypocalcemia occurs most frequently when neck dissection is combined with total thyroidectomy.

Adolescent↗