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Biomedical subjects

T M McCulloch

Publications and source records attributed to T M McCulloch.

At least 37 records · Page 2Linked to original sources
PubMed1998

Intra-operative ultrasound-guided drainage of parotid abscess.

Parotitis complicated by parotid abscess remains a potentially life-threatening problem. Conventional surgical treatment involves incising the parotid parenchyma in the direction of the facial nerve until the abscess is located and evacuated. Intra-operative ultrasound greatly assists in localizing the abscess and in ensuring its complete drainage. Expeditious and exact localization of the abscess reduces operative time. Equally importantly, ultrasound-assisted drainage reduces surgical dissection and the potential for facial nerve damage.

Abscess↗
PubMed1998

Medialization laryngoplasty with expanded polytetrafluoroethylene. Surgical technique and preliminary results.

Symptomatic unilateral laryngeal paralysis may be treated successfully by a wide variety of surgical techniques. These techniques share the concept that stabilization of the paralyzed vocal fold in a median position will improve glottic function. Medialization laryngoplasty with expanded polytetrafluoroethylene (ePTFE) incorporates the general principles of established medialization procedures, yet is unique in its simplicity. The technique does not require special instrumentation, employs incremental adjustment of vocal fold position, and utilizes an implantable material with a long history of patient safety. We describe this new technique and report on the outcome of our first 16 patients treated. No surgical or implant-related complications have occurred. Voice results were measured from preoperative and postoperative video and voice recordings by four independent observers using a standardized assessment tool. Voice grade and breathiness were evaluated on a four-point scale (0 = normal and 3 = abnormal, extreme). The mean overall grade improved from 2.3 +/- 0.6 to 1.1 +/- 0.6, and breathiness from 2.0 +/- 0.8 to 0.4 +/- 0.4. The technique is simple, the implant material has been in clinical use for decades, and the voice results are good to excellent.

Adolescent↗
PubMed1998

Role of substance P in the laryngeal chemoreflex.

The laryngeal chemoreflex (LCR) is a potentially life-threatening reflex that is elicited in immature animals by the topical application of water to the laryngeal mucosa. The reflex response is characterized by immediate apnea and laryngeal adduction and delayed cardiovascular instability. The cardiorespiratory changes of the LCR may be life-threatening, particularly in very immature animals such as piglets under 2 weeks of age. The afferent and efferent limbs of the LCR are mediated through the vagus nerve, but the neuromediators responsible for the reflex changes have not yet been clearly elucidated. Previous agonist and antagonist studies in immature dogs demonstrated that substance P, a sensory tachykinin, mediates the life-threatening esophagolaryngeal adductor reflex elicited by distal esophageal sensory nerve stimulation. This study was conducted to determine if substance P also plays a role in mediating the LCR. The LCR response was compared before and after treatment with intravenous substance P antagonist (Pfizer CP-96,345-1) in eight piglets (mean 27.7 days of age). The laryngeal and cardiovascular responses of the animals following intravenous administration of the tachykinins substance P, neurokinin A, and neurokinin B were also assessed. Pretreatment with substance P antagonist did not alter the LCR's duration of apnea (p > .10), laryngeal adductor response, or early change in mean arterial pressure (p > .10), although the early maximal heart rate response was significantly altered (p < .01). Intravenous substance P, neurokinin A, and neurokinin B did not reproduce the laryngeal respiratory response of the LCR. We conclude that substance P, neurokinin A, and neurokinin B are not key neurotransmitters of the LCR.

Animals↗
PubMed1997

Botulinum neurotoxin injection after total laryngectomy.

BACKGROUND: One of several causes of tracheoesophageal puncture (TEP) speech failure after total laryngectomy is disturbance in relaxation of the pharyngoesophageal (PE) segment. We introduce the use of chemical denervation of the PE segment through botulinum neurotoxin (Botox) injection to improve TEP speech. METHODS: An analysis was performed on eight patients who received Botox injections for TEP speech problems after total laryngectomy at the University of Iowa between June 4, 1991 and August 8, 1994. Retrospective chart review identified the evolution of pretreatment evaluation and injection technique which became standardized in April 1992. Prospective evaluation of results was recorded by a single speech pathologist who subjectively identified the response to Botox in all patients and recorded pressure readings at the tracheostoma site during speech in 6 patients. RESULTS: Seven of the eight patients were noted to have improved TEP speech following injection. Five of these seven patients experienced substantially improved speech, three of whom had no ability to produce speech prior to the Botox injection. CONCLUSION: Botox injection is a safe and effective method of improving TEP speech in selected patients with disturbed relaxation of pharyngoesophageal segment.

Adult↗
PubMed1997

Risk factors for pulmonary complications in the postoperative head and neck surgery patient.

BACKGROUND: Pulmonary complications are a primary source of increased cost and morbidity in surgically treated head and neck cancer patients. This study investigates potential risk factors related to postoperative pulmonary complications (pneumonia, adult respiratory distress syndrome (ARDS), and prolonged mechanical ventilation) in head and neck cancer patients. METHODS: Data from 144 major head and neck procedures performed at the University of Washington between 1985 and 1991 were retrospectively reviewed. Univariate and multivariate analysis were used to evaluate preoperative and perioperative variables identified as potential risk factors for postoperative pulmonary complications. RESULTS: Fifteen percent of patients had a postoperative pulmonary complication, (n = 21: 18 postoperative pneumonia; 2 ARDS; and 4 prolonged ventilation). The most common pneumonia pathogen was Staphylococcus aureus (62%). Univariate analysis identified smoking and weight loss as significant factors associated with pulmonary complications. The variables preoperative blood urea nitrogen, white blood cell count, and operative chest flap closure all approached but did not reach significance. Multivariate analysis of a subgroup of patients identified smoking history and perioperative antibiotic choice as the only independently significant variables. CONCLUSIONS: Patient smoking history was the primary variable related to postoperative pulmonary problems, with evidence of increasing risk with increased exposure. Other variables added only limited additional risk association information after multivariate analysis.

Analysis of Variance↗
PubMed1997

Pectoralis major myofascial flap: a valuable tool in contemporary head and neck reconstruction.

BACKGROUND: The pectoralis major myofascial (PMMF) unit is rapidly mobilized, reliable, and extremely useful in a number of clinical situations calling for vascularized soft-tissue coverage in the head and neck. Although free-tissue transfer has emerged as the preferred method of reconstruction for a large variety of defects in the head and neck, the pectoralis major muscle should be considered when vascularized soft-tissue coverage is required in this area. METHODS: A retrospective chart review of 24 PMMF flaps performed at the University of Iowa Hospitals and Clinics between January 1, 1991, and May 1, 1996, was undertaken. Outcomes were evaluated relative to accomplishing the established preoperative surgical goals. RESULTS: Utilization of the PMMF flap was grouped according to four primary indications: (1) protection of threatened great vessels or free flap vascular pedicles in situations of wound breakdown due to fistula or infection (7 cases); (2) vascularized soft-tissue coverage of great vessels or free-flap vascular pedicles and prevention of potential wound breakdown in surgical defects in which compromised healing was anticipated (7 cases); (3) closure of small pharyngeal defects (2 cases); or (4) vascularized coverage of the mandible following debridement for osteoradionecrosis (8 cases). The PMMF flap was 100% successful when the surgical goal was to protect exposed vascular structures and promote wound healing in the presence of fistula or infection. The PMMF flap was 100% successful in the protection of vascular structures and prevention of wound breakdown in cases where compromised wound healing was anticipated. The PMMF flap provided closure, and a vascularized surface for mucosalization, when used to primarily reconstruct small pharyngeal defects. The PMMF flap provided definitive closure in 5 of 8 (62.5%) cases of osteoradionecrosis of the mandible when it was used to invest the remaining mandibular bone. Three of 8 cases (37.5%) required further surgical management and were considered failures. An acceptable cosmetic outcome was obtained in women undergoing this procedure by using an inframammary incision. The preoperative goal of the PMMF flap procedure was met in 21 of 24 (87.5%) cases. There was a major complication rate of 12.5% as well as a minor complication rate of 12.5%. CONCLUSION: In cases requiring the protection of vital vascular structures from infection, salivary secretions or skin flap breakdown, the PMMF flap should be considered. The PMMF flap is an excellent reconstructive option in selected clinical situations, where vascularized soft-tissue coverage is required in the head and neck.

Adult↗
PubMed1997

Resource utilization and patient morbidity in head and neck reconstruction.

Many papers have addressed the technical aspects of free tissue transfer in head and neck cancer patients. However, there has not been a critical assessment of the impact of free tissue transfer on resource utilization and patient morbidity compared with pedicle flap reconstructions. Two cohorts of patients derived from 245 consecutive reconstructions were tightly matched by age, site, stage, and histology, yielding 44 patient pairs differing in method of reconstruction. Patients undergoing free flap reconstruction spent more time in the operating room than those reconstructed with pedicled flaps (993 min vs. 777 min, P < 0.0001). The group with free flap reconstruction spent fewer days in the surgical intensive care unit and hospital (2 days vs. 2.5 days; 18.5 days vs. 22.6 days). This difference is attributed to the paucity of postoperative complications in the group with free flap reconstruction (fistula formation 4.5% vs. 21%, P < 0.04). These data indicate that the continued use of sophisticated reconstructive techniques in head and neck cancer patients is economically sound as assessed by patient morbidity and resource utilization.

Critical Care↗
PubMed1996

Laryngeal activity during swallow, phonation, and the Valsalva maneuver: an electromyographic analysis.

To better understand the mechanisms of airway protection during swallow, the authors of this study performed an electromyographic (EMG) analysis on the thyroarytenoid (TA) and interarytenoid (IA) muscles during a variety of tasks. The tasks included high, low, and comfortable pitch phonation, the Valsalva maneuver, saliva swallow, and 5- and 10-mL water swallows. Raw EMG signals were analyzed to obtain root mean square data, which correspond to a relative magnitude of muscle activation. The data show that both TA and IA muscles generate a similar level of relative activation, with the greatest electrical activity observed during swallow tasks followed by the Valsalva maneuver and phonation. The duration, onset, offset, and pattern of activity during the swallowing tasks also showed close synchronization between the two muscles. These data can be used in designing therapy for voice disorders and pharyngeal dysphagia.

Adult↗
PubMed1995

Free-tissue transfer reconstruction of midfacial and cranio-orbito-facial defects.

OBJECTIVE: To review our results using free-tissue transfer to reconstruct midfacial and cranio-orbito-facial defects. DESIGN: Case series. SETTING: The University of Iowa Hospitals and Clinics, Iowa City. PATIENTS: Fourteen of 21 patients had defects that resulted from ablative oncologic surgery; six had severe mid-facial trauma; and one had Romberg's disease. INTERVENTIONS: Four latissimus dorsi, 11 rectus abdominis, three scapula, and four forearm free-tissue transfer flaps were used. MAIN OUTCOME MEASURES: Adequate flap separation of vital structures (intracranial contents and carotid artery) from the sinonasal or oropharyngeal cavities; restoration of palatal competence, oral diet, and speech intelligibility; maxillary dental rehabilitation; aesthetic results; complications; and the patient's return to social activities outside the home after surgery. RESULTS: The intracranial contents (six cases) or carotid artery (four cases) were protected from sinonasal or oropharyngeal contamination by the reconstructive flap in all cases in which this was required. Functional closure of the palate with the flap or a prosthesis was possible in 12 of the 13 patients with a palatal defect; seven of these 13 patients have had full maxillary dental rehabilitation. Twenty patients take an oral diet. Sixteen patients have normal or easily understood speech. Fourteen patients engage in social activities outside the home, and eight have returned to full-time employment. No vascular flap failures occurred in this series. CONCLUSIONS: The use of free-tissue transfer flaps is a safe and effective technique for repairing large midfacial and cranio-orbito-facial defects resulting from ablative oncologic surgery or trauma.

Adult↗
PubMed1995

Blood transfusion as a risk factor for death in stage III and IV operative laryngeal cancer. The Department of Veterans Affairs Laryngeal Cancer Study Group.

OBJECTIVE: To evaluate the role of a blood transfusion in a patient population with head and neck cancer that was treated with combined therapy (surgery and radiation). DESIGN: Retrospective, nonrandomized end point study. Univariate and multivariate analysis of 24 variables, including transfusion status. SETTING: The Veterans Affairs Cooperative Study (Cooperative Studies Program 268). PATIENTS: Patients in the surgical arm of the study (166 patients) underwent surgery and postoperative radiation therapy for advanced (stage III and IV) laryngeal cancer. MAIN OUTCOME MEASURES: Identification of variables related to patient time to death. RESULTS: The univariate analysis identified age, clinical N (lymph node) class, primary tumor site, number of pathologically positive lymph nodes, extracapsular spread, pretreatment screening hematocrit, hematocrit and albumin level at 1 month after treatment, intraoperative fluids and units of blood, and total units of blood as significant (P < .05). The stepwise multivariate models identified independent significance in clinical and pathologic node status, hematocrits at both screening and 1 month, extracapsular spread, albumin level at 1 month, age, and primary site. The position of each variable within the individual regression models varied. CONCLUSIONS: Clinical N class or pathologic node status occupied the first position of predictive significance in all models. Blood transfusion status never retained independent significance in any multivariate assessment.

Aged↗
PubMed1995

The efficacy of routine central venous monitoring in major head and neck surgery: a retrospective review.

STUDY OBJECTIVE: To further define the efficacy of routine central venous catheter placement for major head and neck surgery from the standpoint of fluid and blood administration, and various other parameters of perioperative management. DESIGN: Randomized, retrospective chart review. SETTING: University-affiliated medical center. PATIENTS: 104 patients who had undergone major head and neck surgery (defined as surgery lasting longer than 4 hours with a predicted blood loss of 500 ml or greater) at the University of Iowa Hospitals and Clinics between 1985 and 1992. MEASUREMENTS AND MAIN RESULTS: Central venous monitoring was used in 51 of the 104 (49%) procedures. Patients with and without central monitors did not differ in age, weight, preoperative laboratory values [i.e., hemoglobin (Hb), blood urea nitrogen (BUN), creatinine), incidence of significant cardiac or renal disease, or a smoking history exceeding 30 pack years. In addition, these patients did not differ with respect to the following intraoperative characteristics: general type of anesthetic; duration of surgery; estimate of blood loss; Hb values; lowest urine output per hour; development of oliguria; total urine output; amount of replacement of blood, colloid, or crystalloid; development of systolic blood pressure less than 70 mmHg; or use of a myocutaneous flap. Patients also did not differ with respect to the following postoperative characteristics: duration of stay in the surgical intensive care unit or hospital, BUN or creatinine values on days 1 and 2, total urine output or the development of oliguria on days 1 through 3, incidence of reintubation, fever on days 1 through 5, wound dehiscence, death, myocardial infarction, or the development of pneumonia, pulmonary edema, or sepsis. Patients with central monitors had a greater incidence of having a tracheostomy performed and a slightly lower Hb level on the first postoperative day than those without central monitors. CONCLUSIONS: The study raises doubt about the efficacy of routine central venous catheter placement as a necessary guide for fluid and blood administration for these procedures, or as a necessary adjunct for several other parameters of perioperative management. It suggests the need for a randomized, prospective evaluation.

Blood Urea Nitrogen↗
PubMed1994

A preliminary study of the prognostic role of electromyography in laryngeal paralysis.

Confidence in the reliability of laryngeal electromyography to predict recovery is critical if this tool is to be used to select the type and timing of surgical intervention. The characteristics of electromyography of 14 patients with unilateral vocal fold paralysis were assessed to determine which factor or combination of factors would be most useful in determining prognosis. We examined the duration, amplitude, waveform morphology, root-mean-square, and time interval from onset to electromyography recording. The results supported the concept that electromyography recordings are valuable in determining prognosis if performed before 6 months and preferably within 6 weeks of onset of laryngeal paralysis. A positive prognosis for laryngeal recovery was indicated when the following electromyography features were present in the immobile vocal fold: (1) normal motor unit waveform morphology, (2) overall electromyography activity characterized by a root-mean-square value greater than 40 microV in any one task, and (3) no electrical silence during voluntary tasks. On the basis of this criteria our overall correct prognostic rate was 89%.

Electromyography↗
PubMed1992

Head and neck liposarcoma. A histopathologic reevaluation of reported cases.

Head and neck liposarcoma is an extremely rare tumor. As with all rare lesions there is a void in the literature regarding tumor activity and treatment response. It is difficult to make rational treatment plans and advise patients as to probable treatment response and prognosis. To obtain as much information as possible from available data we have reviewed the world literature and reevaluated the descriptive histopathologic findings and treatment response of reported cases. Seventy-six cases have been reported since 1911. We added another case and then reclassified the previously reported lesions according to a current histopathologic system (well-differentiated, myxoid, round-cell, and pleomorphic lesions). We assessed tumor activity and treatment response by histopathologic tumor type. Paralleling tumor activity in other anatomic regions, all patients with myxoid and well-differentiated tumors did well; all were alive at the end of follow-up, eight of eight and 11 of 11, respectively (average follow-up, 5.7 and 4.8 years). This is compared with a 50% mortality rate in the round-cell and pleomorphic groups by the end of 2 years, (two of three and six of 11 patients alive, respectively). The likelihood of recurrence correlated with extent of tumor removal, and metastatic disease was identified almost exclusively with the tumor of the round-cell and pleomorphic variants. Surgical excision remains the primary treatment modality, while radiation and chemotherapy appear to be of limited utility.

Head and Neck Neoplasms↗
PubMed1992

Lidocaine effects on the laryngeal chemoreflex, mechanoreflex, and afferent electrical stimulation reflex.

The use of lidocaine hydrochloride as either a topical or intravenous agent has become a common practice for minimizing laryngospasm and the reflex cardiovascular effects resulting from upper airway manipulation. The efficacy and mechanism of action of lidocaine for this purpose remain unclear. We evaluated the effect of lidocaine on the laryngeal chemoreflex (LCR), mechanoreflex (LMR), and superior laryngeal nerve electrical stimulation adductor reflex (SLN-ESAR) in piglets. Cardiopulmonary responses were used to assess LCR and LMR. Latency following SLN stimulation was used to assess SLN-ESAR. Intravenous lidocaine hydrochloride at 3 mg/kg produced no suppression of the LCR, LMR, or latency (SLN-ESAR onset latency before lidocaine 11.7 +/- 0.7 milliseconds, after lidocaine 12.2 +/- 0.5 milliseconds; peak latency before lidocaine 13.2 +/- 0.2 milliseconds, after lidocaine 13.4 +/- 0.4 milliseconds). Topically applied lidocaine at the same dose eliminated both LCR and LMR responses in all animals, with return of reflex responses 15 minutes after application. No effect on the SLN-ESAR was seen with application of topical lidocaine. This study supports topical lidocaine as a suppressant of laryngeal mucosal neuroreceptors without central neural reflex effects. Intravenous lidocaine did not affect peripheral neuroreceptors, nor did it significantly affect the latency of the SLN-ESAR neural reflex arc. Intravenous and topical lidocaine differ in mechanism of action and efficacy with regard to modulation of reflex effects induced by laryngeal stimulation.

Administration, Topical↗
PubMed1991

Complications of translaryngeal intubation.

The human larynx is complex and serves multiple functions. Unfortunately, endotracheal tubes do not reproduce all these functions. They serve well as air passages but cannot do so without damaging the mucosa of the posterior larynx. It appears that complications secondary to airway problems in the operating room are decreasing as the use of oximetry and capnometry becomes routine. It is hoped that this reduction in complications will carry over into the chronic care setting as such monitoring becomes the standard after intubations. Compared with malposition of the tube, most of the other complications of intubation are minor. However, knowledge of the various complications can ensure avoidance of many and early detection and correction of others.

Humans↗