Accessing the Basilar Artery Apex: Is the Temporopolar Transcavernous Route an Anatomically Advantageous Alternative?

The restricted operative field, difficulty of obtaining proximal vascular control, and close relationship to important anatomic structures limit approaches to basilar apex aneurysms. We used a cadaveric model to compare three surgical transcavernous routes to the basilar apex in the neutral configuration. Five cadaveric heads were dissected and analyzed. Working areas and length of exposure provided by the transcavernous (TC) approach via pterional, orbitozygomatic, and temporopolar (TP) routes were measured along with assessment of anatomic variation for the basilar apex region. In the pterional TC and orbitozygomatic TC approaches, the mean length of exposure of the basilar artery measured 6.9 and 7.2 mm, respectively (p = NS). The mean length of exposure in a TP TC approach increased to 9.3 mm (p < 0.05). Compared with the pterional and orbitozygomatic approaches, the TP TC approach provided a larger peribasilar area of exposure ipsilaterally and contralaterally (p < 0.05). The multiplanar working area related to the TP TC approach was 77.7 and 69.5% wider than for the pterional TC and orbitozygomatic TC, respectively. For a basilar apex in the neutral position, the TP TC approach may be advantageous, providing a wider working area for the basilar apex region, improving maneuverability for clip application, fine visualization of perforators, and better proximal control.     

Endoscope-assisted supraorbital approach to the retroinfundibular area: a cadaveric study

The purpose of this study is to investigate and evaluate the exposure and maneuverability of this areas provided by an endoscope-assisted supraorbital approach and to compare that to a microscopic supraorbital approach. We exposed microscopically the optico-carotid and the infrachiasmatic windows after a supraorbital craniotomy executed using an eyebrow incision. We then proceeded to explore the retroinfundibular area using these two windows either using the microscope alone or using the endoscope–microscope combination where the microscope was used to (1) guide instrument and endoscope insertion into the surgical field, and (2) explore (with microscopic 3-d vision) subsegments of the endoscopic field of view. We compared the exposure and surgical maneuverability of the approach utilizing the microscopic mode alone with the endoscope-assisted mode. We evaluated the exposure and the surgical maneuverability of key anatomical structures of the retroinfundibular area. The structures evaluated included the diaphragma sellae, the dorsum sellae, the posterior clinoid process, the pituitary stalk, the mammillary bodies, the tuber cinereum, the oculomotor nerves, the basal pons, the upper trunk of the basilar artery, the superior cerebellar arteries, the posterior cerebral arteries, the posterior communicating arteries and the basilar bifurcation. The exposure and the surgical maneuverability were significantly higher in the endoscope-assisted mode (P?<?0.0001). Based on our study, the endoscope-assisted supraorbital retroinfundibular approach is associated with larger exposure and maneuverability than the pure microscopic approach. Further clinical information is required to verify the results of this study.     

Side-Cutting Aspiration Device for Endoscopic and Microscopic Tumor Removal

The authors present a unique side-cutting instrument (NICO Myriad, Indianapolis, IN) with variable aspiration designed specifically for tumor resection. The study included retrospective review of data collected from 10/2009 to 01/2011. We detail the use of the Myriad in 31 patients with the following pathologies: meningioma (n=16), chordoma (n = 3), schwannoma (n = 3), pituitary adenoma (n = 2), metastasis (n = 3), hemangioblastoma (n = 1), craniopharyngioma (n = 1), and nasopharyngeal tumors (n = 2). Surgical approaches included expanded endonasal approach (n = 19), endoscopic brain port (n = 3), supraorbital “eyebrow” craniotomy (n = 3), retrosigmoid suboccipital craniotomy (n = 3), pterional craniotomy (n = 1), extreme far lateral (n = 1), and laminectomy (n = 1). Successful tumor resection was achieved in 30 cases. Instrument failure was noted in only one extremely fibrous meningioma. The design of this instrument facilitated maneuvering through narrow corridors while providing direct visualization of the suction aperture during tumor resection. These features allowed for tumor removal without injury to adjacent neurovascular structures. The side-cutting aspiration device allows safe and effective tumor removal. Its low profile, variable aspiration, and lack of thermal heat energy are particularly useful in tumor resection through narrow corridors, such as endonasal, port, and keyhole approaches. The multifunctional nature of the instrument (suction, scissors, and dissectors) minimizes multiple exchanges, facilitating tumor resection through these minimal access corridors.     

Comparison of Surgical Freedom and Area of Exposure in Three Endoscopic Transmaxillary Approaches to the Anterolateral Cranial Base

Objective Endoscopic ipsilateral endonasal transmaxillary, contralateral endonasal transseptal transmaxillary, and Caldwell-Luc approaches can access lesions within the retromaxillary space and pterygopalatine fossa. We compared the exposure and surgical freedom of these transmaxillary approaches to assist with surgical decision making. Design Four cadaveric heads were dissected bilaterally using the three approaches just described. Prior to dissection, stereotactic computed tomography (CT) scans were obtained on each head to obtain anatomical measurements. Surgical freedom and area of exposure were determined by stereotaxis. Main Outcome Measures Area of exposure was calculated as the extent of the orbital floor, maxillary sinus floor, nasal floor, and mandibular ramus exposed through each approach. Surgical freedom was the area through which the proximal end of the endoscope could be freely moved while moving the tip of the endoscope to the edges of the exposed area. Results The mean exposed area was similar: 9.9 ± 2.5 cm² (Caldwell-Luc), 10.4 ± 2.6 cm² (ipsilateral endonasal), and 10.1 ± 2.1 cm² (contralateral transseptal) (p > 0.05). The surgical freedom of the Caldwell-Luc approach (113 ± 7 cm²) was greater than for either endonasal approach, 76 cm²± 15 (p = 0.001) (ipsilateral endonasal) and 83 cm² ± 15 (p = 0.003) contralateral transseptal. Conclusions Our work demonstrates that the Caldwell-Luc endonasal approach offers greater surgical freedom than either approach for anterolateral skull base targets, although these approaches offer similar exposure.     

Quantitative Anatomical Study of Tailored Far-Lateral Approach for the VA-PICA Regions

Objective The extent of the far-lateral approach (FLA) has not yet been quantified for the region of the vertebral and posterior inferior cerebellar arteries (VA-PICA). We quantitatively analyzed six main sequential steps of the FLA. Methods A modified small FLA (msFLA) and a classic large FLA (clFLA) were performed sequentially on both sides of five cadaveric heads. A frameless navigational system was used to quantify the angle of attack for the origin (T1) and lateral medullary segment (T2) of the PICA and the surgical area of exposure above and below the vagus nerve (cranial nerve [CN] X). Results The total area of exposure above CN X increased significantly (p < 0.05) from the msFLA to the clFLA. However, the surgical exposure area below CN X did not change (p > 0.05). C1 hemilaminectomy increased (p < 0.05) the vertical angle of attack, and drilling the posteromedial third of the occipital condyle increased (p < 0.05) the horizontal angle of attack to the origin of the PICA. Conclusions For the VA-PICA region, the msFLA offered a similar practical surgical working area and similar angles of attack when compared with the clFLA. The FLA should be tailored based on the location, size, and pathology of lesions and on the exposure required for effective surgical treatment.     

Surgical ablation and free flap reconstruction in children with malignant head and neck tumors

We assessed the feasibility and safety of free flap reconstruction in children undergoing extensive surgical excision of malignant head and neck tumors. We performed a retrospective review in a tertiary referral center of all patients aged 18 years or younger who underwent free flap reconstruction following resection of malignant head and neck tumors at our institution. Main outcome measures included complications at the primary and donor sites, functional and esthetic outcome, and tumor control. Eight of the 237 (3.4%) free flap reconstructions were performed on children. All tumors were malignant sarcomas. Ablative surgery was via a transfacial (n = 4) or a combined approach (n = 4). Transferred free flaps were the rectus abdominis (n = 3), gracilis (n = 3), fibula (n = 1), and anterolateral thigh (n = 1). The mean follow-up was 25.5 months. The overall early and late complication rates were 50% and 25%, respectively. There were no flap losses and no donor site complications. Functional outcome, including mastication, deglutition, and speech, was satisfactory. Local tumor control rate at last follow-up was 87.5%. Free flap reconstruction is an efficient and relatively safe technique for reconstructing surgical defects of the head and neck in children undergoing extensive surgery for malignant disease.     

Craniofacial Resection for Sinonasal Malignant Tumors: Statistical Analysis of Surgical Outcome over 17 Years at a Single Institution

We present a retrospective analysis of surgical outcome of sinonasal malignant tumors. Overall survival (OS), disease-specific survival (DSS), local control (LC), and disease-free survival (DFS) were calculated in 32 patients. Prognostic factors for survival and functional outcomes were investigated. The median follow-up period was 70 months. At 5 years, OS, DSS, LC, and DFS rates were 0.722, 0.745, 0.851, and 0.707, respectively. Prognostic factors for poor OS were involvement of the frontal sinus (p = 0.023), T classification (T4, p = 0.025), surgical complications (p = 0.029), chemotherapy (p = 0.035) postsurgical infection (p = 0.043), involvement of the orbit (p = 0.048), histology (squamous cell carcinoma, p = 0.049), and radiotherapy (p = 0.043). Prognostic factors for poor DSS were radiotherapy (p = 0.030), chemotherapy (p = 0.036), positive surgical margin (p = 0.034), and T classification (T4, p = 0.050). LC was adversely influenced by surgical procedure (combined frontotemporal resection, p = 0.035) and positive surgical margin (p = 0.049). DFS was adversely influenced by positive surgical margin (p = 0.001). Prognostic factors for poor functional outcome were postsurgical infection (p = 0.039), postsurgical complications (p = 0.040), tumor location (maxillary sinus, p = 0.042, orbit, p = 0.0002), number of sinuses involved (number of sinuses involved was inversely proportional to functional outcome, p = 0.027), T classification (T4 p = 0.007), pathology (squamous cell carcinoma, p = 0.023), and chemotherapy (p = 0.048). Craniofacial resection was an effective surgical option.     

Comparing Operative Exposures of the Le Fort I Osteotomy and the Expanded Endoscopic Endonasal Approach to the Clivus

Objectives We compare surgical exposures to the clivus by Le Fort I osteotomy (LFO) and the expanded endoscopic endonasal approach (EEEA). Methods Ten cadaveric specimens were imaged with 1.25-mm computed tomography. After stereotactic navigation, EEEA was performed followed by LFO. Clival measurements included lateral and vertical limits to the midline lower extent of exposure (t test). Results For EEFA and LFO, respectively, maximal lateral exposure in millimeters (mean ± standard deviation) was 24.5 ± 3.7 and 24.5 ±  − 3.8 (p = 0.99) at the opticocarotid recess (OCR) and 25.1 ±  − 4.1 and 24.1 ±  − 3.0 (p = 0.53) at the foramen lacerum level; lateral reach at the hypoglossal canals was 39.0 ±  − 5.88 and 56.1 ±   − 5.3 (p = 0.0004); and vertical extension was 56.0 ±  − 4.1 and 56.3 ±  − 3.4 (p = 0.78). Conclusions For clival exposures, LFO and EEEA were similar craniocaudally and laterally at the levels of the OCR and foramen lacerum. LFO achieved greater exposure at the level of the hypoglossal canal.     

Transzygomatic Approach with Intraoperative Neuromonitoring for Resection of Middle Cranial Fossa Tumors

The authors reviewed the surgical experience and operative technique in a series of 11 patients with middle fossa tumors who underwent surgery using the transzygomatic approach and intraoperative neuromonitoring (IOM) at a single institution. This approach was applied to trigeminal schwannomas (n = 3), cavernous angiomas (n = 3), sphenoid wing meningiomas (n = 3), a petroclival meningioma (n = 1), and a hemangiopericytoma (n = 1). An osteotomy of the zygoma, a low-positioned frontotemporal craniotomy, removal of the remaining squamous temporal bone, and extradural drilling of the sphenoid wing made a flat trajectory to the skull base. Total resection was achieved in 9 of 11 patients. Significant motor pathway damage can be avoided using a change in motor-evoked potentials as an early warning sign. Four patients experienced cranial nerve palsies postoperatively, even though free-running electromyography of cranial nerves showed normal responses during the surgical procedure. A simple transzygomatic approach provides a wide surgical corridor for accessing the cavernous sinus, petrous apex, and subtemporal regions. Knowledge of the middle fossa structures is essential for anatomic orientation and avoiding injuries to neurovascular structures, although a neuronavigation system and IOM helps orient neurosurgeons.     

Factors influencing the accuracy of iliosacral screw placement in trauma patients

Correct placement of iliosacral screws remains a surgical challenge. The aim of this retrospective study was to identify parameters which impact the accuracy of this technically demanding procedure. Eighty-two patients with vertically unstable pelvic injuries treated with a total of 147 iliosacral screws were included. Assessment of postoperative CT scans revealed screw misplacement in 13 cases (8%), of which six occurred following insertion of two unilateral screws into S1. Six screw misplacements occurred in patients with dislocation injuries of the posterior pelvis. Comparison of a navigated and the standard technique revealed a decreased screw misplacement rate in the navigated group (15% standard vs. 3% navigation, p < 0.05). In addition, the malposition rate was influenced by the surgeon’s individual experience (20% for low vs. 3.9% for high volume surgeons, p < 0.05). Overall, the accuracy of iliosacral screw placement depends on the number of screws inserted into S1 and the extent of dislocation. In experienced hands, the use of navigation represents a helpful tool to improve the placement accuracy.     

Direct subcutaneous injection of polyethylene particles over the murine calvaria results in dramatic osteolysis

Purpose

The murine calvarial model has been widely employed for the in vivo study of particle-induced osteolysis, the most frequent cause of aseptic loosening of total joint replacements. Classically, this model uses an open surgical technique in which polyethylene (PE) particles are directly spread over the calvarium for the induction of osteolysis. We evaluated a minimally invasive modification of the calvarial model by using a direct subcutaneous injection of PE particles.

Methods

Polyethylene (PE) particles were injected subcutaneously over the calvaria of C57BL6J ten-week-old mice (“injection” group) or were implanted after surgical exposure of the calvaria (“open” group) (n = 5/group). For each group, five additional mice received no particles and served as controls. Particle-induced osteolysis was evaluated two weeks after the procedure using high-definition microCT imaging.

Results

Polyethylene particle injection over the calvaria resulted in a 40 % ± 1.8 % decrease in the bone volume fraction (BVF), compared to controls. Using the “open surgical technique”, the BVF decreased by 16 % ± 3.8 % as compared to controls (p < 0.0001).

Conclusions

Direct subcutaneous injection of PE particles over the murine calvaria produced more profound resorption of bone. Polyethylene particle implantation by injection is less invasive and reliably induces osteolysis to a greater degree than the open technique. This subcutaneous injection method will prove useful for repetitive injections of particles, and the assessment of potential local or systemic therapies.     

Does the surgical approach in one stage bilateral total hip arthroplasty affect blood loss?

Purpose

It is not clear whether type of surgical approach affects the amount of blood loss in one-stage bilateral total hip arthroplasty (THA). This study therefore aims to examine if type of surgical approach can affect peri-operative blood loss and allogeneic blood transfusion in patients undergoing one-stage bilateral THA.

Methods

Records of 319 patients who underwent one-stage bilateral THA from January 2004 to June 2011 were retrospectively reviewed. Patients were divided into two groups: direct anterior (DA) approach (75 patients) and direct lateral (DL) approach (244 patients). Blood loss was calculated using a previously validated formula. Blood loss and need for allogeneic blood transfusion were compared between the two groups. Additionally, the effects of using cell saver and surgical approach were evaluated in a multivariate analysis.

Results

Compared to the DL approach, calculated blood loss was significantly lower in the DA group (2,813.90 ± 804.13 ml vs 3,617.03 ± 1,148.47 ml) and a significantly lower per cent of patients needed allogeneic blood transfusion in the DA group (26.6 vs 52.4 %). Intra-operative cell saver was used in 36 patients. Compared to the non-cell saver group, mean blood loss was significantly higher in the cell saver group (4,061.0 ± 1,285.55 ml vs 3,347.71 ± 1,083.85 ml), whereas the difference between the two groups regarding allogeneic blood transfusion was not statistically significant. The DA approach was an independent predictor of lower peri-operative blood loss and allogeneic blood transfusion while using cell saver was not.

Conclusions

Our results may be explained by the lower extent of muscular dissection performed in the DA approach. Our findings also indicate that intra-operative cell salvage might not be justified in bilateral THA performed expeditiously.     

The safety and efficacy of minimally invasive discectomy: a meta-analysis of prospective randomised controlled trials

Purpose

The objective of this study was to compare the safety and efficacy of minimally invasive discectomy (MID) with standard discectomy (SD) and determine whether the use of the MID technique could decrease the recurrence of lumbar disc herniation (LDH) after the surgery.

Methods

In February 2014, a comprehensive search was performed in PubMed, EMBASE, Web of Science, Cochrane Library and the Chinese Biological Medicine Database. Only randomised controlled trials (RCT) that compared MID with SD for the surgical management of LDH were included. These trials were carefully picked out following the inclusion and exclusion criteria. Using the Cochrane Collaboration guidelines, two authors independently extracted data and assessed these trials’ quality. The age of the patients, size of incision, surgical time, blood loss, visual analogue scale (VAS) score after the surgery, hospital stay, disc herniation recurrence, X-ray exposure and surgical costs in these studies were abstracted and synthesised by a meta-analysis with RevMan 5.2.0 software, and the main results (VAS score after the surgery and disc herniation recurrence) of publication bias were examined by Stata 12.0.

Results

Overall, 16 trials involving 2,139 patients meeting our criteria were included and analysed. Comparing MID and SD, the former was more likely to increase disc herniation recurrence [relative risk (RR) = 1.95, 95 % confidence interval (CI) 1.19–3.19, p = 0.008], and it involved a smaller size of incision [mean difference (MD) = −1.91, 95 % CI −3.33 to −0.50, p = 0.008], shorter hospital stay, longer operating time (MD = 11.03, 95 %C I 6.62–15.44, p < 0.00001) and less blood loss (MD = −13.56, 95 % CI −22.26 to −4.87, p = 0.002), while no statistical difference appeared with regard to the age of the patients, VAS score after the surgery, X-ray exposure, hospital stay and surgical costs.

Conclusions

Based on available evidence, MID results in less suffering for patients during the hospital course with a similar clinical efficacy compared to SD. This makes MID a promising procedure for patients with LDH; however, to popularise it greater effort is required to reduce disc herniation recurrence.     

Working area and angle of attack in three cranial base approaches: pterional, orbitozygomatic, and maxillary extension of the orbitozygomatic approach

OBJECTIVE: This study was designed to quantify the operative exposure obtained in the pterional, orbitozygomatic, and modified orbitozygomatic with maxillary extension surgical approaches. METHODS: The pterional and orbitozygomatic approaches and a variation of the orbitozygomatic osteotomy that included an extra centimeter of bone resection in the inferior direction ("maxillary extension") were performed on cadaveric heads. For each surgical exposure, the working area was determined by using triangles defined with anatomic points. The "angle of attack" of the approaches for the same target point was determined with the use of a robotic microscope. RESULTS: The maximum allowable angle of attack was significantly greater with the orbitozygomatic approach (37.2 +/- 4.7 degrees) than that with the pterional approach (27.1 +/- 4.3 degrees) (P < 0.001). The angle of attack with the maxillary extension (42.0 +/- 4.9 degrees) was significantly greater than that with the orbitozygomatic approach (P < 0.001). The working areas were 281, 343, and 371 mm(2) for the pterional, orbitozygomatic, and maxillary extension approaches, respectively. The orbitozygomatic approach with maxillary extension had a significantly larger working area than the pterional approach (P = 0.011). CONCLUSION: Increments in bony removal open a wider angle in which to work more than they increase the actual amount of working area. Increasing the amount of bone removed by using an orbitozygomatic approach instead of a pterional approach converts a narrow space into a wide portal, allowing surgeons to work closer to the surgical target while decreasing the need for brain retraction. Extending the orbitozygomatic approach into the maxillary region also improves the exposure area and angle, but less significantly.     

Surgical approaches to the cavernous sinus: a microsurgical study

The surgical approaches to the cavernous sinus were examined in 50 adult cadaveric cavernous sinuses using magnification of X3 to X40. The following approaches were examined: 1) the superior intradural approach directed through a frontotemporal craniotomy and the roof of the cavernous sinus; 2) the superior intradural approach combined with an extradural approach for removing the anterior clinoid process and unroofing the optic canal and orbit; 3) the superomedial approach directed through a supraorbital craniotomy and subfrontal exposure to the wall of the sinus adjacent to the pituitary gland; 4) the lateral intradural approach directed below the temporal lobe to the lateral wall of the sinus; 5) the lateral extradural approach for exposure of the internal carotid artery in the floor of the middle cranial fossa proximal to the sinus; 6) the combined lateral and inferolateral approach, in which the infratemporal fossa was opened and the full course of the petrous carotid artery and the lateral wall of the sinus were exposed and; 7) the inferomedial approach, in which the medial wall of the sinus was exposed by the transnasal-transsphenoidal route. It was clear that a single approach was not capable of providing access to all parts of the sinus. The intracavernous structures best exposed by each route are reviewed. The osseous relationships in the region were examined in dry skulls. Anatomic variants important in exposing the cavernous sinus are reviewed.     

The effect of epineurotomy on the median nerve volume after the carpal tunnel release: a prospective randomised double-blind controlled trial

Purpose

The purpose of this study was to evaluate the effects of epineurotomy on the post-surgical median nerve volume and clinical outcomes in carpal tunnel syndrome (CTS) patients with a prominent nerve narrowing.

Methods

This was a prospective, randomised, double-blind controlled trial. Patients (n = 50) were randomised (1:1) to open-field surgical carpal tunnel release followed by a longitudinal epineurotomy of the nerve (test), or to open-field release without epineurotomy (control).

Results

The nerve volume was slightly larger in the test group 90 days post-surgery (by 10.5 %, p = 0.157) but not 180 days post-surgery. No relevant electropyhsiological or clinical difference between groups and no effect of the nerve volume was observed. The subjective pain reduction was slightly more prominent in the control group at 180 days. Larger post-surgical nerve volume was associated with lower pain, but only in the control group.

Conclusions

Even in selected CTS patients, longitudinal epineurotomy confers no benefit regarding the nerve volume or clinical outcomes over a simple carpal tunnel release.     

Giant Cell Tumor of Tendon Sheath: Case Series and Review of Literature

Recurrence of Giant cell tumor of the tendon sheath (GCTTS) is an unresolved issue, though it is a non malignant condition. The authors operated on fourteen cases of GCTTS, after fine needle aspiration cytology confirmation and using a magnifying loupe for complete excision of the lesion including the satellite nodules. In only one case recurrence was noted which was successfully managed by a second wide excision. Preoperative diagnosis and meticulous surgical technique were found the only predictive factor of recurrence. During the 5 year period from 2002, 12 patients [11 females, 1 male, mean age 29.5, ranging from 10–53 years] underwent excision of giant cell tumor of tendon sheath of the hand. The lesions were found over the thumb [n = 7], ring finger [n = 1], index finger [n = 1], and over the hand [n = 2]. The lesions were classified using the Al-Qattan classification. The most common presentation was with a mass over the hand, with a predilection to the thumb [n = 7]. Radiological changes in the form of bony indentation was seen in only 2 cases. FNAC was inconclusive in 2 out of the 12 cases. Due to the high incidence of recurrence, pre-operative planning aided by a tissue diagnosis with fine needle aspiration cytology, wide surgical exposure, and meticulous dissection with help of magnification are imperative for a successful outcome in GCTTS.     

Endoscopic endonasal approaches to the cavernous sinus: surgical approaches

OBJECTIVE: After completion of an earlier endoscopic transsphenoidal anatomic study, we studied various endoscopic transsphenoidal approaches using cadaveric specimens to develop endoscopic endonasal surgical approaches to the cavernous sinus. METHODS: Ten cavernous sinuses in five artery-injected adult cadaveric heads were studied with 0-, 30-, and 70-degree angled 4-mm rod-lens endoscopes. The extent of the surgical exposure, the skewed endoscopic anatomic view, and the maneuverability of surgical instruments through their relative operating spaces were studied after various endoscopic endonasal approaches via one nostril. RESULTS: The paraseptal approach was used between the nasal septum and the middle turbinate and provided exposure at the anteromedial portion of the cavernous sinus. The contralateral paraseptal approach rendered a slightly more medial view at the cavernous sinus than did the ipsilateral approach. This approach offered limited surgical access to the lateral vertical compartment. The middle turbinectomy approach allowed surgical access to the lateral wall of the cavernous sinus, except for the superior orbital fissure and the orbital apex. The middle meatal approach, which was made between the middle turbinate and the lateral nasal wall, revealed the entire lateral vertical compartment of the cavernous sinus, including the orbital apex and the superior orbital fissure. However, its lateral tangential surgical trajectory and the absence of dedicated surgical tools limited the surgeon's surgical maneuverability. A combination of the middle turbinectomy and middle meatal approaches increased the operating space. CONCLUSION: Various endoscopic endonasal surgical approaches to the cavernous sinus were studied using adult cadaveric head specimens.     

Anterior Elongation as a Minimally Invasive Alternative for Sagittal Imbalance—A Case Series

Background

Degenerative and iatrogenic conditions may lead to flat back or even to kyphotic deformity, and sagittal imbalance can cause significant clinical impairment. Minor imbalance cases are usually treated with conservative care. Among currently popular surgical techniques for the correction of sagittal imbalance are posterior-based procedures, which are associated with access-related risks (mostly neurological) and postoperative morbidity risks.

Purpose

This study aims to report a minimally invasive lateral approach using hyperlordotic cages in the treatment of mild sagittal imbalance. Radiological correction, clinical improvement, and safety will be analyzed.

Methods

Eight patients (mean age 71.8 years, SD 7.8; mean BMI 27.5, SD 2.3) with symptomatic sagittal imbalance were retrospectively reviewed. Eight cases were treated by anterior interbody fusion with lordotic cages. A minimally invasive lateral retroperitoneal approach was used in the surgical procedures, with or without percutaneous pedicle screw supplementation.

Results

No major complications occurred and just one case needed revision for direct decompression. Clinical outcomes Visual Analog Scale score changed from 88 at preoperative visit to 51 at 1-week visit, and Oswestry Disability Index score decreased from 82 at preoperative visit to 44 at 6-week visit. The 6-month radiological assessment revealed improvement in spinopelvic parameters: Focal lordosis improved from 2.3° ± 7.7 to 27.1° ± 6.7. Sagittal vertical alignment improved from 11.7 ± 5.3 to 6.2 ± 4.0 cm. Preoperative sacral slope improved from 20.1° ± 5.8 to 29.4° ± 10.3 and preoperative pelvic tilt improved from 35.2° ± 5.2 to 23.8° ± 4.3. Short-term results indicate that the minimally invasive lateral approach can be applied to the treatment of mild sagittal imbalance, with special advantage in elderly patients or those in which posterior approaches are relatively contraindicated.