Minimally invasive spine surgery: an animal model for endoscopic approach to the anterior cervical and upper thoracic spine

BACKGROUND: Minimally invasive video-assisted techniques are currently used for thoracic and lumbar spine surgery with the aim of reducing the morbidity. Recently, an endoscopic approach has been used for endocrine neck surgery, with reduced pain and improved cosmetic results. PURPOSE: To develop an animal model for an endoscopic neck approach to the anterior cervical and upper thoracic spine. METHODS: Five pigs were used. A combination of one 5- and two 3-mm laparoscopic instruments was used to dissect the spine, and dedicated instrumentation was then used to perform discectomies. Carbon dioxide was insufflated at 10 mm Hg. Dissection was carried out upward and downward on the anterior aspect of the spine; discectomy was performed at various levels and evaluated at autopsy. RESULTS: All pigs tolerated the procedure well. Visibility of the cervical spine was excellent, and exposure from C1 to T3 was obtained. For discectomy, an additional 10-mm trocar was inserted, and discectomy of C3-C4 and C4-C5 was performed. Proper location and adequacy were confirmed at autopsy. CONCLUSION: The endoscopic neck approach allows exposure of the entire cervical spine and the upper thoracic spine in the porcine model. This approach has the potential to reduce the morbidity associated with the open cervical approach and provides a wider view and exposure than conventional open surgery. The availability of the porcine model allows the acquisition of the necessary technical skills before introducing this advanced procedure in humans.     

Minimally invasive video-assisted parathyroidectomy

BACKGROUND: The standard surgical procedure for parathyroidectomy consists of bilateral cervical exploration and the visualization of all four parathyroid glands. However, improved preoperative localization techniques and the availability of intraoperative intact parathyroid hormone (iPTH) monitoring now allow single adenomas to be treated with minimally invasive techniques. METHODS: Patients with primary hyperthyroidism (pHPT), who were found to have one unequivocally enlarged parathyroid gland on preoperative ultrasound and 99mTc-SestaMIBI scintigraphy underwent minimally invasive video-assisted parathyroidectomy by an anterior approach. Intraoperatively, rapid electrochemiluminescense immunoassay was used to measure iPTH levels shortly before and 5, 10, and 15 mins after excision of the adenoma. The operation was considered successful when a >50% decrease in preexcision iPTH levels was observed after 5 min. RESULTS: Between November 1999 and May 2000, 10 of 22 patients with pHPT were deemed eligible for the minimally invasive approach. In all cases, the adenoma was removed successfully. However, in two cases, intraoperative iPTH monitoring did not show a sufficient decrease in iPTH values. Subsequent cervical exploration revealed a double adenoma in one case and hyperplasia in the other. CONCLUSIONS: Even when high-resolution ultrasound and 99mTc-SestaMIBI scintigraphy are used, the presence of multiple glandular desease cannot be ruled out entirely. When the minimally invasive approach is contemplated, intraoperative iPTH monitoring is indispensible to ensure operative success. However, in selected cases, minimally invasive parathyroidectomy represents an excellent alternative to the conventional technique.     

Minimally invasive video-assisted parathyroidectomy and intraoperative parathyroid hormone monitoring. The first 36 cases and some pitfalls

Background: The success of parathyroid surgery depends on the identification and removal of all hyperactive parathyroid tissue. At this writing, bilateral cervical exploration and identification of all parathyroid glands represent the operative standard for primary hyperparathyroidism (pHPT). However, improved preoperative localization techniques and the availability of intraoperative parathyroid hormone monitoring prepare the way for minimally invasive procedures. Methods: Patients with pHPT and one unequivocally enlarged parathyroid gland on preoperative ultrasound and 99mTc-SestaMIBI scintigraphy underwent minimally invasive video-assisted parathyroidectomy by an anterior approach. Intraoperatively, a rapid chemiluminescense immunoassay was used to measure intact parathyroid hormone (iPTH) levels shortly before and then 5, 10, and 15 min after excision of the adenoma. The operation was considered successful when more than a 50% decrease in preexcision iPTH levels was observed after 5 min. Results: Between October 1999 and November 2001, 36 of 82 patients with pHPT were eligible for a minimally invasive approach. A conversion to open surgery became necessary in five patients because of technical problems. In three cases, intraoperative iPTH monitoring showed no sufficient decrease in iPTH values. In these cases, subsequent cervical exploration showed one double adenoma and two hyperplasias, respectively. In two patients we had difficulty interpreting intraoperative iPTH values, resulting in persistent pHPT. Conclusions: Despite the use of high-resolution ultrasound and 99mTc-SestaMIBI scintigraphy, the presence of multiple glandular disease cannot be ruled out completely. Intraoperative iPTH monitoring to ensure operative success is indispensible for a minimally invasive approach. Despite our problems with iPTH monitoring in two patients, we believe that in selected cases, minimally invasive parathyroidectomy represents an attractive alternative to conventional surgery.     

Minimally invasive lateral mass plating in the treatment of posterior cervical trauma: surgical technique

OBJECTIVE: The technique of lateral mass fixation restores the posterior tension band and provides effective stabilization in patients with many types of traumatic injuries. However, postoperative wound pain is not uncommon. The objective of this work is to describe a modified technique of minimally invasive lateral mass plating for cervical spine trauma. METHODS: Patient 1 was a 64-year-old woman who had been in a motor vehicle accident and sustained bilateral C5-C6 facet dislocation with posterior C5-C6 distraction. She was otherwise neurologically intact, and attempts at closed reduction were not successful. Patient 2 was a 16-year-old girl who had also been in a motor vehicle accident but had an incomplete spinal cord injury. She had an unstable burst fracture of C7 with posterior C5-C6 distraction. Both patients underwent anterior cervical fusion followed by staged minimally invasive posterior fusion with good results. A dilator tubular retractor system (METRX) was used to access the bilateral lateral masses through a small midline incision under fluoroscopic guidance. Lateral mass screws were then placed by using a modified Magerl technique, securing two-hole plates on each side onto the lateral masses, performed through the METRX system. We also successfully performed four-level lateral mass plating in a cadaveric cervical spine using a 2-cm skin incision. CONCLUSIONS: We describe successful placement of lateral mass screw and plate constructs with the use of a minimally invasive approach by means of a tubular dilator retractor system. This approach preserves the integrity of the muscles and ligaments that maintain the posterior tension band of the cervical spine.     

Minimally invasive thyroid and parathyroid surgery is not a question of length of the incision

INTRODUCTION: Postoperative cosmesis in the neck is often a major concern of patients, particularly women, undergoing thyroid or parathyroid surgery. Therefore, a reduction in the length of the cervical incision, and even more so, having no scar in the neck, is particularly appealing to these patients. Over the last years, many different so-called minimally invasive procedures have been proposed for the treatment of thyroid and parathyroid diseases, the primary aim being to improve the cosmetic results. Nevertheless, the concept of surgical invasiveness cannot be limited to the length or to the site of the skin incision. It must be extended to all structures dissected during the procedure. Therefore, minimally invasive thyroidectomy or minimally invasive parathyroidectomy should properly be defined as operations through a short, less than 3 cm, and discrete incision that permits direct access to the thyroid or parathyroid gland, resulting in a focused dissection. In addition, type of anesthesia, duration of the operation, postoperative pain, complication and success rates, and long-term outcome should also be taken into account to assess surgical invasiveness. CONCLUSION: Thyroid and parathyroid operations that minimize the incision but keep it in the neck may be considered minimally invasive not only in respect of the size of the skin incision but also, and above all, in respect of the accessibility of the operative field and extent of dissection. These operations have some advantages over conventional cervicotomy in terms of postoperative pain and cosmetic results. Until now, there is no evidence to state that morbidity of these new approaches is at least equal to the conventional equivalent. Operations that employ an extracervical approach, which have the advantage of leaving no scar in the neck, cannot reasonably be described as minimally invasive, as they require more dissection than conventional open surgery.     

Minimally invasive thyroid surgery for diagnostic excision of solitary thyroid nodules

OBJECTIVE: Various techniques for minimally invasive thyroid surgery (MITS), including endoscopic and video-assisted procedures, have now been described. Based on our units experience with minimally invasive parathyroidectomy via a lateral incision, a similar technique for minimally invasive thyroid lobectomy has been developed and assessed. METHODS: The last 203 consecutive thyroid procedures using the MITS technique, performed between July 2002 and June 2006, comprised the study group. Inclusion criteria for initial surgery were: initial nodule < 3.0 cm; no preoperative evidence of malignancy; absence of clinical multinodular change. A 2.5-cm lateral incision, using a headlight illumination, provided optimal exposure. RESULTS: A total of 202 patients underwent 203 MITS procedures over the 4-year period, with one patient undergoing bilateral MITS. The procedures included 155 thyroid lobectomies and 48 nodule excisions; 31 of the patients underwent a minimally invasive parathyroidectomy (MIP) during which an ipsilateral thyroid nodule was removed. The mean tumour size was 17.3 mm, but the mean size of the thyroid lobe removed was 39.5 mm. Final diagnoses included benign multinodular goitre (26%), follicular adenoma (22%) and carcinoma (20%). The complication rate was low, with one permanent recurrent laryngeal nerve (RLN) palsy (anterior division only) (0.5%), four RLN neuropraxias which recovered (2%), and one haematoma not requiring re-operation (0.5%). The rate of complications was not significantly different from 819 conventional open hemithyroidectomies performed over the same period. CONCLUSION: MITS is a safe and feasible alternative to open thyroid surgery in appropriately selected cases. It offers a valuable option for diagnostic excision biopsy in patients with thyroid nodules demonstrating an atypical fine-needle biopsy whilst avoiding the need for a standard cervical "collar" incision.     

Minimally invasive video-assisted thyroidectomy: five years of experience

BACKGROUND: In the last decade, development of videolaparoscopic surgery allowed several operations to be performed with minimally invasive techniques, making them less invasive and painful. Neck surgery was also involved in this effort, in spite of the skepticism shown by some authors. STUDY DESIGN: Minimally invasive video-assisted thyroidectomy was developed in 1998, and since then, about 600 operations have been performed. Access was the same as was previously described for parathyroidectomy; it was based on a small central incision (1.5 cm) and on external retraction without neck insufflation. RESULTS: From July 1998 to October 2003, 579 patients were selected from 5,450 for minimally invasive video-assisted thyroidectomy. The operation consisted of a total thyroidectomy in 312 patients and lobectomy in 267 patients. Mean operative time was 41 +/- 19.5 minutes (range 15 to 120 minutes) for lobectomy and 51.6 +/- 18.8 minutes (range 30 to 140 minutes) for total thyroidectomy. Postoperative hospital stay was 24 hours (overnight discharge) for all patients. Complications were postoperative bleeding (0.1%), recurrent nerve palsy (1.3%), and definitive hypoparathyroidism (0.2%). CONCLUSIONS: After 5 years of experience using this approach for various indications, we achieved a good esthetic result with an operative time comparable to that of conventional open surgery. Minimally invasive video-assisted thyroidectomy was found to be a safe operation, with advantages over traditional procedures represented by better cosmetic outcomes and postoperative course, as demonstrated by visual analogue scales and statistically analyzed numeric scales.     

Minimally invasive videoscopic parathyroidectomy by lateral approach

Methods: A videoscopic parathyroidectomy was performed in 22 patients presenting with primary hyperparathyroidism (PHPT). No patient had undergone previous neck surgery, presented with goiter or had a history of familial PHPT. Ultrasonography and Sestamibi scanning were performed preoperatively. Rapid intact parathormone assay was used during surgery. Through a 15-mm transversal skin incision on the anterior border of the sternocleidomastoid muscle (SCM), the fascia connecting the lateral portion of the strap muscles and the thyroid lobe with the carotid sheath was gently divided, far enough to visualize the prevertebral fascia. Once enough space was created, three trocars were inserted: a 12-mm trocar through the incision and two 2.5-mm trocars on the line of the anterior border of the SCM, above and below the first trocar. Carbon dioxide was insufflated to 8 mmHg. Unilateral video-assisted parathyroid exploration was then carried out using a 10-mm O° endoscope. Once the adenoma had been identified, the trocars were removed. Then, directly through the skin incision, the thyroid lobe was retracted medially and the adenoma was extracted after clipping its pedicle. Results: Among the 23 enlarged glands, 20 (80%) were correctly identified by endoscopic exploration: mean weight 843 mg (100 mg to 5 g). The exploration was unilateral in 17 patients but bilateral in 5. Mean time of unilateral endoscopic exploration was 84 min (40–130 min). Morbidity was represented by two superficial hematomas. All 22 patients were biochemically cured, follow-up ranging from 3 months to 14 months. Conclusions: This preliminary study demonstrates that minimally invasive videoscopic parathyroidectomy by lateral approach is a feasible surgical procedure. Received: 24 November 1998 Accepted: 3 March 1999     

Minimally invasive tubular access for posterior cervical foraminotomy with three-dimensional microscopic visualization and localization with anterior/posterior imaging

Background contextPosterior cervical foraminotomy allows decompression of the nerve root with preservation of motion. A previously described endoscopic technique utilizes minimally invasive muscle splitting with routine outpatient discharge.PurposeThe approach allows a modified tubular retraction system to be used with three-dimensional visualization and anterior/posterior fluoroscopic imaging, thus allowing easy visualization even in large patients. This approach also allows safe docking of the retractor system on the lateral mass, thus avoiding the cervical spinal canal during exposure.Study designProne position is utilized, with localization and docking of instrumentation accomplished with anterior/posterior fluoroscopy. Surgery is performed with microscope-facilitated, three-dimensional visualization.MethodsPatients were placed in the prone position. Spinal needle localization was used for initial localization followed by a stab wound and placement of a 14-mm tube using sequentially enlarging dilators. Frequent use of anterior/posterior fluoroscopy avoided inadvertent medial placement of the instruments in the canal. A standard neurocapable operating microscope was used with 10X magnification and 400-mm focal length.ResultsA new minimally invasive posterior cervical approach was performed on 222 patients without dural penetration.ConclusionsPosterior foraminal cervical surgery with three-dimensional access and localization with anterior/posterior fluoroscopic imaging allows safe, reproducible docking on the cervical spine with subsequent exploration of the foramen and routine outpatient discharge. Complications related to difficulty with lateral localization in the lower cervical spine, and with inadvertent entry into the cervical spinal canal with possible catastrophic result are thus avoided.     

Use of single-lumen tube for minimally invasive and hybrid esophagectomies with prone thoracoscopic dissection: case series

Minimally invasive and hybrid minimally invasive esophagectomy (MIE) is a technically challenging procedure. Anesthesia for the same is equally challenging due to special requirements of the video-assisted thoracoscopic technique used and shared operative and respiratory fields. Standard ventilatory strategy for this kind of surgery has been 1-lung ventilation with the help of a double-lumen tube. Prone positioning for thoracoscopic dissection facilitates gravity-dependant collapse of the operative side lung induced by a unilateral capnothorax, thus making the use of single-lumen endotracheal tube a feasible option for this surgery. We report our experience of 10 consecutive cases of minimally invasive esophagectomy conducted in prone position at our center and the use of single-lumen endotracheal tube for ventilation.     

Surgery for sporadic primary hyperparathyroidism: controversies and evidence-based approach

Introduction Sporadic primary hyperparathyroidism is due to single adenoma in over 90–95% of instances. Careful medical history and precise preoperative identification of the enlarged gland by parathyroid Tc-mibi scintigraphy and neck ultrasound allow selecting patients for minimally invasive parathyroidectomy, a focused intervention with minimal skin opening and tissue dissection. Small (<300 mg) adenomas continue to challenge preoperative imaging, and most of them will still require a bilateral exploration. Conclusion Surgery should never be indicated on the basis of positive or negative preoperative localization studies. Intraoperative quick parathyroid hormone measurements seem particularly helpful for cases with equivocal localization studies. The best minimal access approach is still a matter of debate, and options include small central incision, video-assisted parathyroidectomy, minimal lateral open approach, and purely endoscopic access via lateral approach. Radioguided surgery does not seem to have a role in routine cases but may be useful to find adenomas during reintervention on scarred difficult surgical fields.     

Minimally invasive, totally gasless video-assisted thyroid lobectomy.

BACKGROUND: Neck surgery is one of the newest fields of application of video-assisted surgery. We developed a technique for minimally invasive, totally gasless video-assisted thyroid lobectomy. METHODS: The procedure was accepted by a patient with a follicular nodule of the left lobe of the thyroid. We performed a left thyroid lobectomy through a single 20-mm horizontal skin incision, just above the sternal notch, after inserting a 5-mm 30 degrees laparoscope, by using both endoscopic and conventional instrumentation. RESULTS: The recurrent laryngeal nerve and the parathyroid glands were easily identified and preserved. The operating time was 2.5 hours. No complication occurred. The postoperative stay was 2 days. The cosmetic result was excellent CONCLUSIONS: We concluded that our technique is feasible and safe. This makes us optimistic about the future of minimally invasive, video-assisted thyroid surgery.     

Limits and drawbacks of video-assisted parathyroidectomy

BACKGROUND: Minimally invasive video-assisted parathyroidectomy (MIVAP) is a novel minimally invasive approach to primary hyperparathyroidism (PHPT). It is a gasless operation characterized by a single central incision and external retraction. This paper describes the drawbacks and limitations of this procedure based on a 5-year experience and 260 operations. METHODS: Of 364 patients with PHTP, 260 were selected for MIVAP. In most patients a unilateral minimally invasive exploration was performed. RESULTS: MIVAP was carried out successfully in 239 patients with a mean operating time of 40 (range 20-180) min. Conversion to cervicotomy was required in 21 patients (8.1 per cent). Complications included recurrent nerve palsy in two patients (0.8 per cent), haemorrhage that required reoperation 6 h after parathyroidectomy in one patient (0.4 per cent) and transient hypoparathyroidism in six patients (2.5 per cent). In five patients (2.1 per cent) persistent PHPT developed shortly after surgery. CONCLUSION: After 5 years of experience, MIVAP appears to be feasible, safe and applicable to the majority of patients with PHPT.     

Minimally invasive cervical expansile laminoplasty: an initial cadaveric study

OBJECTIVE: Expansile laminoplasty has been successfully used to treat cervical myelopathy attributable to canal stenosis. However, detachment of the posterior cervical muscles is thought to contribute to postoperative axial neck pain and kyphosis. Minimizing the amount of muscular dissection might reduce the likelihood of these sequelae. METHODS: Six human cadaveric spines were used to assess the feasibility of a minimally invasive laminoplasty technique. A 22-mm tubular dilator port was used to access the lamina-facet junctions from C2 to C7, through bilateral stab incisions at C4-C5 and C5-C6. Troughs at the lamina-facet junctions were drilled bilaterally, and the contiguous laminae were lifted en bloc from one side. Ten-millimeter rib allograft spacers were inserted to maintain a gap on the open side. RESULTS: Exposure of six cervical levels was easily accomplished with two small incisions on each side. Drilling was achieved without dural violations. The midsagittal spinal canal diameter was increased by a mean of 38% and the spinal canal area was increased by an average of 43% at the level of C5. CONCLUSION: A minimally invasive approach for cervical laminoplasty could be performed in human cadavers. The measured increases in spinal canal space approximated those demonstrated to be associated with stabilization or improvement of neurological status.     

Impact of localization studies on feasibility of minimally invasive parathyroidectomy in an endemic goiter region

BACKGROUND: A localized single-gland disease is the basis for minimally invasive parathyroidectomy (MIP) in primary hyperparathyroidism (PHPT). (99m)Tc sestamibi scanning (MIBI) and high-resolution Doppler ultrasonography (US) are well-established techniques used to localize enlarged parathyroid glands. Additionally, US enables physicians to diagnose subclinical thyroid abnormalities. The aim of this study was to optimize localization results, applying a combined interpretation of MIBI and US, and to analyze the influence of these results on the feasibility of MIP (endoscopic/video-assisted and open) in an endemic goiter region. STUDY DESIGN: One hundred fifty consecutive patients with sporadic PHPT were prospectively subjected to MIBI and US to localize parathyroid lesions and to review the morphology of the thyroid gland. Bilateral cervical exploration was performed in all patients. The feasibility of MIP was calculated retrospectively on the basis of surgical findings and biochemical outcomes at least 12 months postoperatively (normocalcemia in 148 of 150 patients [99%]). RESULTS: Forty-five percent of patients (67 of 148) would have been suitable for minimally invasive endoscopic or video-assisted parathyroid exploration. These procedures would have succeeded in 38% of patients (56 of 148). Sixty-four percent (94 of 148) would have been suitable for minimally invasive open parathyroidectomy, which would have succeeded in 55% (82 of 148 patients). CONCLUSIONS: Not all patients are suitable for MIP. A combined interpretation of MIBI and US results is helpful in planning targeted exploration. In an endemic goiter region minimally invasive open parathyroidectomy is applicable in significantly more patients than is endoscopic and video-assisted MIP.     

Minimally invasive video-assisted subtotal parathyroidectomy with thymectomy for secondary hyperparathyroidism

Background  Secondary hyperparathyroidism (sHPT) is common in patients with chronic renal failure. Bilateral cervical exploration is optimal for patients with sHPT. The aims of this clinical trial are to evaluate the feasibility of video-assisted subtotal parathyroidectomy as an alternative surgical treatment for sHPT. Methods  This prospective study included 12 consecutive patients with sHPT. Surgical indications included a high intact parathormone level, enlarged parathyroid glands, high bone turnover and conditions refractory to medical treatment of hypercalcemia and hyperphosphatemia. Results  All patients underwent minimally invasive video-assisted subtotal parathyroidectomy and trans-cervical thymectomy. Four cervical glands were found in all patients and intrathymic glands were identified in three (25%) patients. Conclusion  Minimally invasive video-assisted subtotal parathyroidectomy offers an alternative method, and this technique can be performed safely for sHPT.     

Cervical video-assisted thoracoscopic surgery using a flexible endoscope for bilateral thoracoscopy

Video-assisted thoracoscopic surgery (VATS) has become the standard of care for pleural evaluation, drainage, and pleurodesis. The major limitations to standard VATS techniques include intercostal pain and the unilateral nature of the procedure. We report on a cervical VATS approach for bilateral thoracoscopy, pleural biopsy, and talc pleurodesis using a flexible video endoscope without any intercostal incision. A 64-year old male with peritoneal carcinomatosis was noted to have significant bilateral pleural effusions. A cervical video-assisted thoracoscopic surgery (C-VATS) procedure was performed through a 2-cm cervical incision using a sterile flexible gastroscope. Bilateral thoracoscopy, pleural drainage, pleural biopsies, lung biopsy, and talc pleurodesis were performed. No thoracic intercostal incisions were performed. Total operative time was 48 minutes. The procedure was successful and the recovery was uneventful. The patient was discharged 4 days after the procedure. C-VATS is an extremely minimally invasive procedure. It avoids intercostal incisions and allows for bilateral pleural procedures through a single small cervical incision.     

Minimally invasive video-assisted parathyroidectomy: lesson learned from 137 cases

Background: Since February 1997, a technique of minimally invasive video-assisted parathyroidectomy (MIVAP) was developed at our institution for the treatment of sporadic primary hyperparathyroidism (sPHPT). In this study we analyzed the entire series of patients who underwent MIVAP during the last 3 years.

Study Design: One hundred thirty-seven patients with sPHPT were selected for MIVAP. Selection criteria were: diagnosis of single adenoma based on preoperative localization studies (ultrasonography, sestamibi scintigraphy, or both), and no previous neck surgery or concomitant large multinodular goiter. The procedure, already described, is performed by a gasless video-assisted technique through a single 1.5-cm central skin incision above the sternal notch. Quick, intraoperative parathyroid hormone assay was used in 134 cases (97.8%) to confirm the complete removal of all hyperfunctioning parathyroid tissue.

Results: Mean operative time was 54.3 ± 22.6 minutes. The conversion rate was 8.8%. One laryngeal nerve palsy was registered (0.7%), as was one case of persistent hyperparathyroidism. In six patients (4.4%) a transient symptomatic postoperative hypocalcemia was observed. Two thyroid lobectomies were associated using the same minimally invasive access. At a mean followup of 15.4 ± 10.6 months, all but two patients were normocalcemic. The cosmetic result was considered excellent by most of the patients (92.8%).

Conclusions: Although not all patients with sPHPT are eligible for MIVAP, this approach can now be proposed in a bigger proportion (67% of patients). As already demonstrated in a previous study, also in a large series of patients, after greater experience has been achieved, the results and the operative time are the same as in traditional surgery, with better cosmetic result and a less painful course.     

Minimally invasive anterior approach to upper cervical spine: surgical technique

OBJECTIVE: The transoral approach of Spetzler is the classic anterior access to the upper cervical spine that provides direct exposure for anterior decompression of the spinal cord. The risks of infection, the limits in extension, and the postoperative recovery difficulties of transmucosal access suggest the use of an alternative anterior extraoral approach in upper cervical surgery. However, this approach results in complications from nerve palsy because of excessive retraction of the hypoglossal and the superior laryngeal nerves. The goal of this work was to provide anatomic data for an anterior retropharyngeal upper cervical approach through a minimally invasive window below the hypoglossal and the superior laryngeal nerves. METHODS: In two adult cadaveric cervical spines, the anterior approach using the Metrx tubular retractor system through a window between the hypoglossal nerve and the superior laryngeal nerve, as well as below these two nerves, is compared in the exposure of C1 and C2 anteriorly with the aid of an operating microscope. RESULTS: A maximum diameter of the internervous window for the tubular retractor is reached beyond which the superior laryngeal nerve will be excessively stretched. Conversely, the tubular retractor can retract the superior laryngeal nerve superiorly without undue tension. Better proximal exposure is also made possible by angling an end-beveled tubular retractor on the mandible without undue compression on the hypoglossal and superior laryngeal nerves, the marginal mandibular branch of the facial nerve, and the submandibular gland. CONCLUSION: This minimally invasive approach can replace transoral surgery, allowing direct anterior access to C1 and C2 while allowing extension to the lower cervical spine.